To see the other types of publications on this topic, follow the link: Ammonium chlorides.
Dissertations / Theses on the topic 'Ammonium chlorides'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Ammonium chlorides.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Gudgel, Katherine Ann. "Growth of ammonium chloride dendrites." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/289878.
Full textAbstract:
The ammonium chloride-water system has been used extensively as a transparent metal analog to model solidification in binary metal alloys. In this work, the growth rate and morphology of NH₄Cl dendrites grown from aqueous solutions were studied. Since an accurate knowledge of the materials parameters is essential to predicting the growth behavior, the equilibrium segregation coefficient was measured and a detailed analysis of the other NH₄Cl-H₂O materials properties cited in the literature was conducted. Isothermal experiments on bulk NH₄Cl-H₂O samples confirmed that the previously reported discontinuity in the growth rate as function of undercooling and associated transition from <100> oriented slowly growing dendrites to rapidly growing <111> dendrites are not artifacts of the sample geometry. Directional solidification experiments conducted to study the dendrite growth morphology revealed oscillations in both the growth rate and orientation. Results from these studies show that both the undercooling at which the <100> to <111> transition occurs and the peak velocity vary with composition. However, the observed shifts toward smaller apparent undercoolings and the narrowing of the oscillations at higher drive velocities result from changes in the local composition caused by the velocity and orientation dependencies of the partition coefficient. The oscillatory behavior of the <111> dendrites can be predicted using the residual <100> compositional field and the applied temperature gradient. By using an anisotropic segregation coefficient, the slow and fast growth rates can be separately modeled as a function of undercooling using the standard dendrite growth equations. While the transition to the <111> morphology can be attributed to the anisotropy in the k-value, several modifications need to be made to the existing dendritic growth models in order to describe the critical transition. Due to the complex relationships between the non-equilibrium segregation coefficient, composition, and growth rate, some of these modeling efforts have been left to future researchers. In addition to the inclusion of the overall anisotropy, our experiments indicate that the long-range compositional and thermal field effects must be incorporated into the dendrite growth models to explain the difference in growth rates of <111> Primary branches when <111> or <100> side-branches are present.
2
Lavigne, André. "Oxydations cupro-catalysees des amines aliphatiques : etudes mecanistiques et applications synthetiques." Paris 6, 1987. http://www.theses.fr/1987PA066470.
Full textAbstract:
Preparation de nitriles a partir d'amines primaires et d'alpha -aminoacides. Les acides amines monosubstutitues rch(nh::(2))co::(2)h donnent le nitrile rcn, alors que les acides amines disubstitues rr'c(nh::(2))co::(2)h conduisent a l'azine rr'c=n-n=cr'r. Les mecanismes proposes font intervenir le cuivre (iii), forme in situ a partir du cuivre (i) et de l'oxygene
3
Grigonis, Aidas. "Benzalkonio ir metenamino analogų antimikrobinio aktyvumo nustatymas in vitro ir jo priklausomybė nuo aerozolio dalelių krūvio." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2007. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20070214_152534-59492.
Full textAbstract:
Antibacterial effectiveness in vitro of the original quaternary ammonium compounds that were synthesized in the Laboratory of Biologically active substances was determined and the dependence of this activity upon chemical structure of the compound was established. Also generalisations have been made concerning the regularity of this dependency, the effectiveness of the compounds was compared to benzalkonium chloride, their advantages and disadvantages were discussed. Acute toxicity of the most effective compound was established and compared to that of benzalkonium chloride.
It was found that these compounds showed good antibacterial activity against Gr+ and Gr- bacteria and low toxicity, thus this original data was summarized in the patent Nr. 4712.
For the first time it was found that upon disintegration of quaternary methenamonium compounds new quaternary ammonium compounds, aldehydes and ammonia are produced. The first two of the three show further antimicrobic activity.
Using quaternary ammonium salts and cholrhexydine a biocide for disinfection was created. The created biocide was tested for effectiveness when used for disinfection of air in the premises, horizontal and vertical surfaces. The compound was used in the form of aerosols and electro-aerosols. The research data showed that strong concentrations of Dezinfektas IV are necessary (up to 30%), but small amount of the solution per volume is enough (20-30 ml/m3). Ten times higher concentration is needed for... [to full text]
4
Yang, Jeongwoo. "Fate and effect of alkyl benzyl dimethyl ammonium chloride in mixed aerobic and nitrifying cultures." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19871.
Full textAbstract:
Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2008.Committee Chair: Spyros G. Pavlostathis; Committee Member: Ching-Hua Huang; Committee Member: John A. Pierson.
5
Wills, Peter. "Novel biocidal formulation." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/novel-biocidal-formulation(776ed624-6717-496f-9b31-ad2edce8e24b).html.
Full textAbstract:
In this modern age, society has become much more aware of the danger bacteria can have on people's health. Personal and household antimicrobial formulations are commonly used within the home to lower the levels of harmful bacteria such as E. Coli, Salmonella and Pseudomonas. The active which kills the bacteria within the formulation is described as a biocide. This research looks at the often neglected potential of cationic polyelectrolyte as a biocide, firstly within solution and secondly in creating an antimicrobial surface. The solution properties and antimicrobial activity for a range of commercially available cationic polyelectrolytes (polymeric quaternary ammonium compounds (QAC) and biguanides) of differing molecular weights were investigated. All polyelectrolytes were observed to have some level of antimicrobial activity. The second phase of this research investigated polyelectrolyte/surfactant/water mixture of similar charge (cationic). Two QAC surfactants were investigated: Alkyl (C12 70%; C14 30%) dimethyl benzyl ammonium chloride (BAC) and Didecyldimethylammonium chloride (DDQ). At a critical concentration, these mixtures segregatively phase separate into a surfactant rich upper phase and polyelectrolyte rich lower phase. This phase separation phenomenon was investigated in respect of surfactant and polyelectrolyte type as well as polyelectrolyte molecular weight. Surfactant type was observed to be the dominant factor in determining the onset of phase separation and by mixing different ratios of surfactants the ability to tune this phase separation concentration was shown. Dilute solutions of these mixtures well below their respective phase separation concentration were then deposited onto glass substrates via a drop cast or inkjet printer method. The surfactant/polyelectrolyte film composites left after drop evaporation ranged from an amorphous film to nodular like structures. The ability to order/structure actives onto a surface could alter active adhesion and surface roughness properties of the film. This change in surface property could consequently affect antimicrobial performance.
6
Dorreyatim, Mohammad. "Cyclic Polarization of AA 3102 in Corrosive Electrolytes Containing Sodium Chloride and Ammonium Sulfate." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc955069/.
Full textAbstract:
Corrosion of all aluminum microchannel heat exchangers present a challenge in automotive and heating, ventilation, and air conditioning (HVAC) industries. Reproducibility of Salt Water Acetic Acid Test (SWAAT) has been questioned and a need to new corrosion tests with better reproducibility has risen. Cyclic polarization, that is an electrochemical test, was explored for its suitability for the assessment of AA 3102 tube material that is currently a popular aluminum alloy used in manufacturing of heat exchanger.
Corrosive electrolytes containing 3.5 % sodium chloride with 0.5 % ammonium sulfate (high chloride) or 0.5 % sodium chloride with 3.5 % ammonium sulfate (high sulfate) at their pH or acidic (pH=4) were used to measure corrosion potential (Ecorr), protection potential (Epp), pitting potential (Epit), Tafel constants (βa and βc), corrosion rate (mpy). Corrosive electrolyte used in SWAAT test (4.2% Sea Salt at pH 2.9) was also used to compare corrosion resistance of AA 3102 in SWAAT electrolyte compared to the other electrolytes used in this research. Scanning electron microscopy (SEM) was used to observe and document sample surface corrosion damage after each electrochemical test on all samples.
Results of the cyclic polarization tests indicated that SWAAT electrolytes was the most aggressive electrolyte resulting in highest corrosion rates compared to all other electrolytes used in this investigation. SEM results indicated AA 3102 alloy exhibited higher pitting tendency in electrolytes with high sodium chloride whereas high sulfate electrolytes cause appearance of uniform corrosion surface damage on this alloy. Both high sulfate and SWAAT electrolytes showed intergranular corrosion but high chloride electrolyte showed severe pitting of AA 3102.
Mohammad Navid Dorreyatim- Cyclic Polarization of AA 3102 in Corrosive Electrolytes Containing Sodium Chloride and Ammonium Sulfate. Master of Science (Mechanical and Energy Engineering), December 2016, 98 pp., references, 31 titles.
7
Svensson, David. "Synthesis and characterisation of polyelectrolytes based on polymers of diallyldimethyl ammonium chloride and poly(styrene-co-butadiene)." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-82344.
Full textAbstract:
In printed electronics there are many polyelectrolytes to choose from. While polyelectrolytes such as polystyrene sulfonic acid can fulfill many ofthe desired functionalities of a semiconductor, there is a need for other polyelectrolytes with other functionalities, such as functionality at low airhumidity and better cross-linking possibilities, while still functioning as a good semiconductor.Within this thesis, there is a description of general polyelectrolytes, as well as various usages.The synthesis and characterization of new polyelectrolytes that have been developed, based upon diallyldimethyl ammonium chloride (DADMAC)and a derivative of polystyrene sulfonic acid (PSSH) is described.The study and experimental testing of the polymers as polyelectrolytes under different conditions is described.
8
Duggirala, Ravi Kumar. "Double diffusive convection during solidification of ammonium chloride - water (NH4CL-H20) mixture in a trapezoidal cavity." FIU Digital Commons, 2004. http://digitalcommons.fiu.edu/etd/3095.
Full textAbstract:
The effect of the initial concentration of ammonium chloride (sub eutectic: C < 19.8 wt. % and eutectic Ce= 19.8 wt. %) and boundary temperatures (Tcold = -30 0C to -10 0C) on the solidification process is examined. Particle Image Velocimetry (PIV) is used in this study to measure the velocity fields in the melt during the solidification process. The distributions of temperatures at discrete locations in the solution and the boundary walls were measured. This study focuses on the solidification of an ammonium chloride-water (NH4Cl- H2O) solution in a trapezoidal cavity with one and two inclined cooling walls.
The thermosolutal convective flow strongly influenced the rate of freezing. An increase in thermal driving force increased the rate of freezing. Increased initial concentration retarded the freezing process and primarily affected the structure of the solid and mush regions.
The results of this study will contribute in understanding the phenomena and bridge the gap between the engineering aspect and physics background for the dynamics of solid phase formation during castings, ingots, and polymerization.
9
Oh, Seung Dae. "Metagenomic and metatranscriptomic investigation of microorganisms exposed to benzalkonium chloride disinfectants." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52928.
Full textAbstract:
Benzalkonium chlorides (BACs) are widely used, broad-spectrum disinfectants and frequently detected in the environment, even at toxic levels for life. Since such disinfectants can induce broad resistance capabilities, BACs may fuel the emergence of antibiotic resistance in the environment. A substantial body of literature has reported that exposure to BACs causes antibiotic resistance; yet, other studies suggest that the resistance linkage is rare, unsystematic, and/or clinically insignificant. Accordingly, whether or not disinfectant exposure mediates antibiotic resistance and, if so, what molecular mechanisms underlie the resistance link remains to be clearly elucidated. Further, understanding how microbial communities degrade BACs is important not only for alleviating the possible occurrence of antibiotic resistance but also reducing the potential risks to environmental and public health.
An integrated strategy that combines metagenomics, metatranscriptomics, genetics, and traditional culture-dependent approaches was employed to provide novel insights into these issues. The integrative approach showed that a microbial community exposed to BACs can acquire antibiotic resistance through two mechanisms: i) horizontal transfer of previously uncharacterized efflux pump genes conferring resistance to BACs and antibiotics, which were encoded on a conjugative plasmid and co-selected together upon BACs and ii) selective enrichment of intrinsically multi-drug resistant organisms. Further, a microbial community adapts to BAC exposure via a variety of mechanisms, including selective enrichment of BAC-degrading species and amino acid substitutions and horizontal transfer of genes related to BAC resistance and degradation. The metatranscriptomic data suggests that the BAC-adapted microbial community metabolized BACs by cooperative interactions among its members. More specifically, Pseudomonas nitroreducens cleaved (i.e., dealkylated) BACs, metabolized the alkyl chain (the dealkylated product of BACs), and released benzyldimethylamine (the other product of BACs), which was further metabolized by other community members (e.g., Pseudomonas putida).
Collectively, this study demonstrates the role of BACs in promoting antibiotic resistance and advances current understanding of a microbial community degrading BACs. The results of this work have important implications for (appropriate) usage of disinfectants and for assessing, predicting, and optimizing biological engineering processes treating BAC-bearing waste streams.
10
Galbraith, S. D. "The response of potassium chloride (KCl), ammonium nitrate (AN) solutions and emulsion explosives to plate impact loading." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599271.
Full textAbstract:
The aim of this study was to investigate the dynamic properties of potassium chloride, AN solutions and a commercial emulsion explosive and to understand their response in terms of shock theory and material properties. A plate impact facility was used to shock the KCl, subjecting it to a uni-axial strain state for the duration of the measurements. Stress and strain histories were recorded using piezo-resistive gauges. KCl is an ionic crystal which, when subject to shocks above 2.2 GPa, has a martensitic phase transformation. The stress histories were explained in terms of the shock and release waves. A novel technique was used to record the reverse phase transformation and to calculate the hysteresis. The assumption that a uni-axial strain state exists behind a phase transformation was verified, for the first time, experimentally. Two techniques were demonstrated that reduce and quantify the piezo-electric response of KCl. Conclusions from this investigation were analysed by two different types of computational simulation. Using a similar methodology to the KCl work a technique has been developed to determine experimentally the Hugoniot of liquids up to pressures of 10 GPa. The Hugoniots of a variety of AN solutions of different strengths and temperatures were recorded. The results were shown to agree with the predictions of two simple equations of state. The technique developed for AN solutions was applied to a commercial emulsion explosive (based on an AN solution) and the Hugoniot determined. The explosive was sensitised by adding quantities of glass micro-balloons and the pressures which induced the first stages of reaction for a given sensitisation were deduced.
11
Craig, Matthew Rankin. "RT-PCR Localization of Phosphoenolpyruvate Carboxykinase (PEPCK) mRNA in Rat Proximal Tubule Segments During Ammonium Chloride Acidosis." VCU Scholars Compass, 1999. http://scholarscompass.vcu.edu/etd/4493.
Full textAbstract:
In metabolic acidosis, the early increase in PEPCK mRNA and enzyme protein content contributes to the accelerated rates of ammonium and glucose formation. In situ hybridization demonstrated that expression of PEPCK was confined to medullary rays of rat kidney cortex in controls and spread throughout the cortex 10 hours following NH4Cl feeding (Am.J. Physiol., 267: F400, 1994). To identify the specific nephron segments expressing PEPCK in control and acidotic conditions, the mRNA for PEPCK along the nephron of the rat kidney was localized using the technique of reverse transcription and polymerase chain reaction (RT-PCR) in individual microdissected S1, S2 and S3 segments of the rat proximal tubule. Two-millimeter segments of tubule were permeabilized, the mRNA reverse transcribed using oligo-dT as a downstream primer and the eDNA product amplified by PCR (35 cycles). Primers specific for β-actin were used to confirm transfer of tubule, and only tubules positive for β-actin were amplified with primers specific for PEPCK. Both primers were designed to span at least one intron to avoid amplification of genomic DNA. The PCR products were detected using agarose gel electrophoresis and ethidium bromide staining. Verification of PCR product was performed by restriction enzyme digestion.
Under control conditions, the number of tubules expressing PEPCK mRNA as detected by RT-PCR was greatest in the S3 segment, moderate in the S2 segment, and least in the S1 segment of the proximal tubule. Ten hours after gavage feeding of 20- mmol/kg bodyweight NH4Cl, strong signals for PEPCK were detected in all three proximal tubule segments. These data demonstrate the ability of the rat kidney cortex to modulate the expression of PEPCK mRNA along the proximal tubule under physiological conditions, and to increase expression of PEPCK mRNA during metabolic acidosis by the recruitment of additional cells in the proximal nephron.
12
Hajaya, Malek Ghaleb. "Fate and effect of quaternary ammonium antimicrobial compounds on biological nitrogen removal within high-strength wastewater treatment systems." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41113.
Full textAbstract:
High strength wastewater (HSWW) generated in food processing industries is characterized by high organic carbon and nitrogen content, and thus high oxygen demand. Biological nitrogen removal (BNR) is a technology widely used for the treatment of HSWW. Food processing facilities practice sanitation to keep food contact surfaces clean and pathogen-free. Benzalkonium chlorides (BACs) are cationic quaternary ammonium antimicrobial compounds (QACs) common in industrial antimicrobial formulations. BAC-bearing wastewater generated during sanitation applications in food processing facilities is combined with other wastewater streams and typically treated in BNR systems. The poor selectivity and target specificity of the antimicrobial BACs negatively impact the performance of BNR systems due to the susceptibility of BNR microbial populations to BAC. Objectives of the research were: a) assessment and quantification of the inhibitory effect of QACs on the microbial groups, which mediate BNR in HSWW treatment systems while treating QAC-bearing HSWW; b) evaluation of the degree and extent of the contribution of QAC adsorption, inhibition, and biotransformation on the fate and effect of QACs in BNR systems. A laboratory-scale, multi-stage BNR system was continuously fed with real poultry processing wastewater amended with a mixture of three benzalkonium chlorides. The nitrogen removal efficiency initially deteriorated at a BAC feed concentration of 5 mg/L due to complete inhibition of nitrification. However, the system recovered after 27 days of operation achieving high nitrogen removal efficiency, even after the feed BAC concentration was stepwise increased up to120 mg/L. Batch assays performed using the mixed liquors of the BNR system reactors, before, during, and post BAC exposure, showed that the development of BAC biotransformation capacity and the acquisition of resistance to BAC contributed to the recovery of nitrification and nitrogen removal. Kinetic analysis based on sub-models representing BNR processes showed that BAC inhibition of denitrification and nitrification is correlated with BAC liquid-phase and solid-phase concentrations, respectively. Simulations using a comprehensive mathematical BNR model developed for this research showed that BAC degradation and the level of nitrification inhibition by BAC were dynamic brought about by acclimation and enrichment of the heterotrophic and nitrifying microbial populations, respectively. The fate and effect of BACs in the BNR system were accurately described when the interactions between adsorption, inhibition, and resistance/biotransformation were considered within the conditions prevailing in each reactor. This work is the first study on the fate and effect of antimicrobial QACs in a continuous-flow, multi-stage BNR system, and the first study to quantify and report parameter values related to BAC inhibition of nitrification and denitrification. Results of this study enable the rational design and operation of BNR systems for the efficient treatment of QAC-bearing wastewater. The outcome of this research provides information presently lacking, supporting the continuous use of QACs as antimicrobial agents in food processing facilities, when and where needed, while avoiding any negative impacts on biological treatment systems and the environment.
13
Tsai, Tsung-hsun 1961. "Hydrodynamical instability of the mushy layer during directional solidification of ammonium chloride solution in a Hele-Shaw cell." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/282278.
Full textAbstract:
Experiments of directional solidification in a Hele-Shaw cell, 240 mm x 245 mm x 1 mm, were carried out to study the effects of convective flows and the evolution of structure in the "mushy layer", consisting of fluid and crystallites. Three different concentrations of ammonium chloride (NH₄Cl) solution, 26%, 27% and 28%, with a constant bottom cooling temperature ranging from 5°C to -20°C were used as an analogue model for metallic alloy systems. The experimental design included techniques using Peltier heat pumps along with PID feedback control for temperature regulation. A shadowgraphic visualization method made possible the simultaneous observation of the evolution of convection in the liquid region and the phenomena of chimney formation within the mushy layer. More than one hundred runs were carried out. Temperature information and simultaneously acquired digital images were recorded automatically. The time evolution of the solidification process was traced by image processing technique from the digital images. Results show that the phenomenon of intermittent plumes frequently occurs. The number of plumes near the liquid-mush interface decreases from a larger number in the beginning to about the same number of high plumes in the liquid region or chimneys in the mush. The number of chimneys is more static than that of plumes due to the relatively low speed of solidification or dissolution. The mush consists of three different layers. A thin layer of generally upward oriented crystal forms rapidly in the beginning, followed by a second layer aggregate gradually covering it. Finally a third layer of dendritic crystals dominates the top of the growing mush. Preliminary experiments in a Hele-Shaw cell inclined at 21 degrees caused the mush structures to develop differently than in the normal geometry. The significant differences include the dendritic crystal form, the lacunae of the mush, the shape of the chimneys, and the porosity changes of the structures. Directions for future research are suggested.
14
Brooks, Matthew A. "Breakpoint Chlorination as an Alternate means for Ammoia-Nitrogen removal at a Water Reclamation Plant." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/9858.
Full textAbstract:
Numerous wastewater treatment processes are currently available for nitrogen removal or ammonia conversion to nitrate. Those that are economically feasible rely mostly on microbiological processes, which are only effective when the microorganisms remain in a healthy state. If a biological process upset was to occur, due to a toxic shock load or cold weather, it may result in a discharge of ammonia or total nitrogen into the receiving water body. The impact of such a discharge could have deleterious effects on aquatic life or human health. The main objective of the breakpoint pilot study was to define optimum breakpoint pilot plant operating conditions which could then be applied to the design of a full scale breakpoint facility and serve as an emergency backup to biological nitrification.
A pilot study was built on site at the Upper Occoquan Sewage Authority's Regional Water Reclamation Facility in Centreville Virginia. Testing was conducted in two phases (I and II) over a two year period in order to determine the operating conditions at which the breakpoint reaction performed best. Tests were performed during Phase I to determine the optimum operating pH, Cl₂:NH₃-N dose ratio, S0₂:Cl₂ dose ratio, and the minimum detention time for completion of the breakpoint reaction. Other testing done during Phase I included several special studies; including examination of appropriate analytical methods for monitoring breakpoint reactions, and investigation of the breakpoint reaction by-product nitrogen trichloride. Phase II testing examined how varying breakpoint operating temperatures, varying influent ammonia concentrations, higher influent organic nitrogen concentrations, and higher influent nitrite concentrations influenced the performance of the breakpoint pilot operation.
Averages of data from operation at three different rapid mix pHs (7.0, 7.5, and 8.0) showed that pilot performance (i.e., ammonia oxidation) improved and the reaction was more stable at the higher operating pHs 7.5 and 8.0. Examination of dose ratios used during the study showed that the ideal operating ratios for this particular water was around 8:1 Cl₂:NH₃-N for the breakpoint reaction and 1.3:1 S0₂:Cl₂ for the dechlorination reaction. Although detention times for completion of the breakpoint reaction varied with pilot influent temperature, it generally required around 30-35 minutes to reach ammonia concentrations of < 0.2 mg/L NH₃-N at 8-12°C. Completion of the breakpoint reaction was found to be quickest at 20°C (the highest water temperature tested at the pilot).
The tests of varying influent ammonia concentrations showed that although higher influent ammonia concentrations (11.0 mg/L) resulted in faster ammonia oxidation rates initially, the pilot operated better and had the same final performance results when the influent ammonia was lowered.
Increasing the organic nitrogen concentrations (~ 1.0 mg/L) in the pilot influent resulted in a slightly higher Cl₂:NH₃-N dose ratio needed to reach breakpoint, a higher S0₂:Cl₂ dose needed to dechlorinate, and resulted in the formation of numerous disinfection byproducts. Increasing the nitrite concentration in the pilot influent increased the chlorination dose requirement.Master of Science
15
Lang, Christopher M. "Development of quaternary ammonium based electrolytes for rechargeable batteries and fuel cells." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-10262006-140639/.
Full textAbstract:
Thesis (Ph. D.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2007.Kohl, Paul, Committee Chair ; Bottomley, Lawrence, Committee Member ; Eckert, Charles, Committee Member ; Fuller, Tom, Committee Member ; Teja, Amyn, Committee Member.
16
Fuska, Jana. "The effect of ammonium chloride and leupeptin on the concentration of prosaposin in endosomes and lysosomes of Marshall cells." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0025/MQ50770.pdf.
Full text
17
Grimaldos, Osorio Nicolas. "Novel Ammonia Storage Materials for SCR Systems : Carbon Materials – Salt Composites." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-75167.
Full textAbstract:
The emissions of nitrogen oxides (NOx) are a serious environmental problem due to its relationship with the formation of smog, acid rain and because they are dangerous for human and animal health. These gases are produced in high quantities in diesel engines used for automotive applications, and different strategies are being used to reduce them, among which are the Selective Catalytic Reduction (SCR) systems. For its operation, it is necessary a supply of ammonia as NOx reducing agent, but the inefficiency at low temperatures of the systems used nowadays has led to the conception of the solid ammonia storage units (ASS). Unfortunately, the materials currently used, i.e. metal halides, do not meet the ammonia supply requirements at low temperatures and have problems of swelling and agglomeration. In order to find a material with better properties for its application as an ammonia sorbent material, MgCl2 composites with different carbon materials (graphite, graphene, and SWCNTs) were prepared by direct mixing and wet impregnation methods, and characterized in this work. Despite the decrease of total storage capacity, improvements were found in thermal stability and mass retention, as well as in sorption and desorption kinetics, making these materials a first result towards the improvement of the solid ammonia storage units.
18
Buehlmann, Peter Hamilton. "Balancing Bromate Formation, Organics Oxidation, and Pathogen Inactivation: The Impact of Bromate Suppression Techniques on Ozonation System Performance in Reuse Waters." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/93530.
Full textAbstract:
Ozonation is an integral process in ozone-biofiltration treatment systems and is beginning to be widely adopted worldwide for water reuse applications. Ozone is effective for pathogenic inactivation and organics oxidation: both increasing assimilable organic carbon for biofiltration and eliminating trace organic contaminants which may pose a threat to human health. However, ozone can also form disinfection byproducts such as bromate from the oxidation of naturally occurring anion bromide. Bromate is a known human carcinogen and is regulated by the EU, WHO, and USEPA to a maximum limit of 10µg/L. In waters high in bromide, especially above 100µg/L, bromate formation becomes a major concern. In the secondary wastewater effluent studied, bromide concentration may exceed 500µg/L. Several bromate suppression techniques have been devised in previous work, including free ammonia addition, monochloramination, and the chlorine-ammonia process. While free ammonia addition was not found to adequately reduce bromate formation below the required MCL, monochloramine addition and the chlorine-ammonia process were found to be effective. However, the impact of these chemical suppression techniques on organics oxidation and disinfection has not been fully studied. This study explored the impact of these bromate suppression techniques at a wide range of ozone doses on bromate formation, pathogenic inactivation, ozone-refractory organics oxidation through the surrogate 1,4-dioxane, and N-nitrosodimethylamine (NDMA) formation. Additionally, bromate suppression mechanisms of monochloramine were explored further through a variety of different water quality parameters, such as through hydroxyl radical exposure and ultraviolet absorption spectrum measurements, which were correlated and utilized to develop a hydroxyl radical exposure predictive model.Master of Science
Ozone is a powerful oxidant used in water treatment in order to degrade contaminants of emerging concern into less harmful moieties and to inactivate pathogens. Upon application to process water, ozone quickly reacts with constituents in the water to form hydroxyl radicals: the most powerful oxidant in water treatment. These hydroxyl radicals, though with extremely short half-lives, are able to degrade ozone-recalcitrant organics, such as 1,4-dioxane through a process called advanced oxidation. Ozone itself also has the capability of inactivating a multitude of pathogenic organisms, including viruses Giardia and Cryptosporidium parvum when specific contacts times are met. However, ozone does have the potential to form disinfection byproducts such as Nnitrosodimethylamine (NDMA) and bromate. NDMA, though not currently regulated by the United States’ Environmental Protection Agency (USEPA), has a drinking water health advisory limit of 10ng/L in the State of California. Bromate, on the other hand, is a known human carcinogen regulated to 10µg/L by the USEPA. Formed within the ozone system from the naturally occurring ion bromide, bromate can be limited through various chemical treatments such as ammonia addition, pH adjustment, monochloramination, and the chlorine-ammonia process. To date, these methods of bromate suppression have not been comprehensively studied in terms of bromate suppression as well as disinfection and organics oxidation in water reuse systems. The purpose of this research was to minimize bromate formation while ensuring NDMA formation was minimized, and disinfection and organics oxidation were maximized. Through this study, system efficiencies were improved and water quality for future generations will be improved.
19
Bezerra, Roseane Madeira. "NÃveis de cloro para codornas japonesas (Coturnix coturnix japonica) nas fases de crescimento e produÃÃo." Universidade Federal do CearÃ, 2010. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=5909.
Full textAbstract:
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorCom o objetivo de avaliar os efeitos dos nÃveis de cloro da raÃÃo nas fases de crescimento e produÃÃo de codornas japonesas foram realizados dois experimentos, nos quais, foram avaliados os nÃveis de 0,07; 0,12; 0,17; 0,22; 0,27 e 0,32% de cloro. No primeiro experimento (fase de crescimento), 384 codornas com um dia de idade distribuÃdas em um delineamento inteiramente casualizado, com seis tratamentos de oito repetiÃÃes de oito aves cada. Conforme os resultados, no perÃodo de 1 a 42 dias, com o acrÃscimo do nÃvel de cloro na raÃÃo houve aumento linear no consumo de raÃÃo (g/ave) e no ganho de peso (g/ave) e reduÃÃo linear na relaÃÃo consumo de Ãgua/consumo de raÃÃo e na umidade das excretas. Entretanto, a conversÃo alimentar (g/g), a ingestÃo de Ãgua (ml/ave/dia), os coeficientes de digestibilidade da matÃria seca (CDMS), do nitrogÃnio (CDN) e da energia bruta (CDEB) e os valores de energia metabolizÃvel aparente (EMA) e aparente corrigida para nitrogÃnio (EMAn) das raÃÃes nÃo foram influenciados pelo nÃvel de cloro Ainda nesse ensaio, observou-se que os nÃveis de cloro recebido pelas codornas na fase de crescimento nÃo afetaram significativamente o desempenho da fase de postura. No segundo experimento, 288 codornas com dezessete semanas de idade foram distribuÃdas em um delineamento inteiramente casualizado, com seis tratamentos, oito repetiÃÃes e seis aves por unidade experimental. Os nÃveis de cloro nÃo influenciaram significativamente o consumo de raÃÃo (g/ave/dia), o consumo de Ãgua (ml/ave/dia), a percentagem de postura (%), o peso do ovo (g), a massa de ovo (g/ave/dia), a conversÃo alimentar (g/g), a umidade das excretas, os coeficientes de digestibilidade da matÃria seca (CDMS), nitrogÃnio (CDN) e energia bruta (CDEB), os valores de energia metabolizÃvel aparente (EMA) e aparente corrigida (EMAn), as Unidades Haugh, as percentagens de albÃmen, gema e casca. Entretanto, a gravidade especÃfica aumentou linearmente com o acrÃscimo de cloro na raÃÃo. Considerando os resultados, podese recomendar que as raÃÃes para codornas japonesas na fase de crescimento (1 a 42 dias) e de produÃÃo formuladas com milho e farelo de soja podem conter nÃveis de cloro de atà 0,32% sem prejuÃzo para os parÃmetros de desempenho e qualidade dos ovos.
In order to evaluate the effects of chlorine levels in the diet of growing and production of Japanese quails were conducted two experiments in which we assessed the levels of 0.07, 0.12, 0.17, 0.22, 0.27 and 0.32% chlorine. In the first experiment (growing phase), 384 quail on a day-old distributed in a completely randomized design with six treatments of eight replicates of eight birds each. According to the results for the period from 1 to 42 days, with the addition of chlorine level in the diet linearly increased feed intake (g/bird) and weight gain (g/bird) and a linear decrease in the ratio of consumption water/feed intake and excreta moisture. However, feed conversion (g/g), water intake (ml/bird/day), the digestibility of dry matter (CDMS), nitrogen (CDN) and gross energy (GEDC) and the values of metabolizable energy (AME) and apparent nitrogen corrected (AME) of feed were not affected by the level of chlorine still in testing, we found that chlorine levels received by the quails in the growing phase did not significantly affect the performance of phase posture. In the second experiment, 288 quail with seventeen weeks of age were distributed in a completely randomized design with six treatments, eight replicates and six birds per experimental unit. Chlorine levels did not significantly influence feed intake (g/bird/day), water consumption (ml/bird/day), the percentage of stance (%), egg weight (g), the mass of egg (g/bird/day), feed conversion (g/g), the moisture of excreta, the digestibility of dry matter (CDMS), nitrogen (CDN) and gross energy (GEDC), the metabolizable energy apparent (AME) and corrected apparent (AME), Haugh Units, the percentages of albumen, yolk and shell. However, the specific gravity increased linearly with the addition of chlorine in the feed. Considering the results, we can recommend diets for Japanese quails in the growing phase (1 to 42 days) and production made with corn and soybean meal can contain chlorine levels up to 0.32% subject to the parameters performance and egg quality
20
Fava, Stefano G. "Effects of chlorine and ammonia compounds on the bioenergetic physiology of rainbow trout, Oncorhynchus mykiss." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0009/MQ31829.pdf.
Full text
21
Mdhlovu, Johan. "Optimisation of water-in-oil microemulsion formulation stabilised by nonylphenol ethoxylated phosphate ester." Diss., Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-03062006-093400.
Full text
22
Rinaldi, Gino. "An X- and Q-band electron paramagnetic resonance study of Mn²§+ in a single crystal of ammonium chloride-iodide in the temperature range 77--295 K." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ64048.pdf.
Full text
23
Moussa, Mariam. "Loading of dendrimer nanoparticles into layer-by-layer assembled Poly(diallyl dimethyl ammonium) chloride-(Poly(acrylic acid))n Multilayer Films : Particle Electrokinetics, Film Structure Dynamics and Elasticity." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0383/document.
Full textAbstract:
Une analyse détaillée des propriétés physico-chimiques des nanoparticules (NP) anthropogéniques est nécessaire pour comprendre à un niveau mécanistique leurs interactions/toxicité potentielle avec/envers les composants biotiques des systèmes aquatiques naturels. Une telle analyse est également requise pour réaliser une évaluation complète et une optimisation de la performance des méthodes d’(ultra)filtration développées pour circonscrire le relargage des NPs dans les milieux aquatiques. Dans ce contexte, l'objectif de cette thèse de doctorat était de déchiffrer les processus physico-chimiques fondamentaux régissant la capture de nanodendrimères carboxylés (PAMAM-COOH) - utilisés fréquemment dans des applications biomédicales – par des films multicouches du type (poly(diallyldiméthylammonium)chlorure-poly(acide acrylique))n ((PDADMAC-PAA)n) assemblés par déposition séquentielle des composantes polymériques cationique et anionique. À cette fin, une étude systématique des propriétés électrohydrodynamiques des NPs PAMAM-COOH a d'abord été effectuée en fonction du pH et de la concentration en sel monovalent du milieu. Sur la base de la théorie électrocinétique de particules molles ayant une fonctionnalité zwitterionique, il est démontré que les caractéristiques électriques interfaciales des NPs considérées sont déterminées à la fois par des contributions électrostatiques de surface et volumique des nanoparticules, lesquelles dependent de l’extension intraparticulaire de la double couche électrique. L’existence de ces deux types de contributions conduit à un changement remarquable de signe de la mobilité des NPs en modifiant la concentration du sel monovalent en solution et à une dépendance prononcé du point de zéro mobilité des NPs avec la concentration de l’électrolyte. En outre, une confrontation quantitative entre résultats expérimentaux et théorie souligne comment les modifications structurales des NPs induites par des changements de pH et de salinité affectent les caractéristiques électrocinétiques des dendrimères. Dans une deuxième partie, la structure, la morphologie et les propriétés mécaniques des films PDADMAC-PAA et leur évolution temporelle dans des conditions de vieillissement naturel ou après traitement thermique ont été déterminées par microscopie à force atomique (AFM) et analyses microspectroscopie Raman. Les résultats démontrent que les films multicouches PDADMAC-PAA de type exponentiel présentent des caractéristiques mécaniques et structurelles typiques de films polyélectrolytes multicouches à croissance linéaire. En particulier, leur relaxation lente vers un état d’équilibre est accélérée après traitement thermique à 60°C et se révèle être intimement liée à l'instabilité de domaines de films riches en PDADMAC, épuisés en eau (faits confirmés par la théorie de la fonctionnelle de la densité) et marqués par la présence de structures caractéristiques en forme de ‘donuts’. Dans une dernière partie, des résultats préliminaires sont donnés pour la dépendance de l'élasticité des films multicouches PDADMAC-PAA avec la concentration en solution de nanodendrimères. Les résultats suggèrent que ces films multicouches complexes constituent une option prometteuse pour la capture et l'élimination de nanodendrimères carboxylés présents en milieux aqueuxA detailed analysis of the physicochemical properties of engineered nanoparticles (NPs) is required to understand on a mechanistic level their interactions/potential toxicity with/towards biotic components of fresh water systems. Such an analysis is further mandatory to achieve a comprehensive evaluation and optimisation of the performance of (ultra)filtration methods developed to prevent NPs release into aquatic media. Within this context, the aim of this PhD thesis was to decipher the basic physico-chemical processes governing the loading of carboxylated-poly(amidoamine) (PAMAM-COOH) nanodendrimers -commonly employed in biomedical applications- into layer-by-layer assembled (poly(diallyl dimethyl ammonium) chloride-poly(acrylic acid))n ((PDADMAC-PAA)n) multilayer films. For that purpose, a systematic investigation of the electrohydrodynamic properties of PAMAM-COOH NPs was first performed as a function of pH and monovalent salt concentration in solution. On the basis of advanced electrokinetic theory for soft particles with zwitterionic functionality, it is demonstrated that the interfacial electrostatic features of the considered NPs are determined both by surface and bulk particle contributions to an extent that depends on electrolyte concentration. This leads to a remarkable NPs mobility reversal with changing monovalent salt concentration and to a marked dependence of the point of zero NPs mobility on electrolyte content. In addition, confrontation between experiments and theory further highlights how pH- and salt-mediated modifications of the NP particle structure affect dendrimer electrokinetic features at large pH and/or low salt concentrations. In a second part, the structure, morphology and mechanical properties of PDADMAC-PAA films, and their evolution over time under natural aging conditions or after thermal treatment, were addressed from atomic force microscopy (AFM) and Raman microspectroscopy analyses. Results evidence that PDADMAC-PAA multilayer films of exponential type exhibit mechanical and structural features that are typical for polyelectrolyte multilayer films with linear growth. In particular, their slow relaxation to equilibrium is accelerated after heating treatment at 60°C and, in line with density functional theory computation, this relaxation dynamics is shown to be intimately connected to instability of film domains rich in PDADMAC, depleted in water and marked by the presence of characteristic donut-like structures. In a final part, the reported dependence of PDADMAC-PAA multilayer films elasticity on concentration of nanodendrimers in bulk solution suggests that these complex multilayer films constitute a promising option to be further investigated for the loading and removal of carboxylated nanodendrimers from aqueous environments
24
Bales, Dustin William. "Optimization of an Advanced Water Treatment Plant: Bromate Control and Biofiltration Improvement." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4286.
Full textAbstract:
The David L. Tippin Water Treatment Facility (DLTWTF) serving the city of Tampa, Florida is an advanced drinking water treatment facility consisting of coagulation/flocculation, ozonation, granular activated carbon biofiltration, and disinfection by chloramine. New regulations and the recent economic crisis pushed the facility to investigate methods to decrease costs and meet regulatory requirements easier.
The two major issues identified as priorities for investigation were the optimization of the biofiltration system and the use of a novel process to reduce the formation of bromate during ozonation.
Optimization of the biofiltration system is needed to remove more of the assorted particles that cause biofilms, nitrification in the distribution system, and high chloramine demand. Previous work improved the removal of particles that cause biofilms and nitrification, but was not able address the removal of particles that cause high chloramine demand to a satisfactory degree. Possible factors affecting this high chloramine decay were identified and evaluated at the pilot scale, including filter depth, chloramination of filter backwash water, media material, and nutrient addition. Non-chlorinated backwash water reduced chloramine demand by approximately 30% for GAC filters, and by approximately 50% for anthracite. Generally, anthracite performed slightly worse than GAC. Nutrient addition showed no effect. Filter depth improved chloramine decay, but not significantly enough to warrant the increased material required
Bromate control is necessary to prevent the formation of bromate, a regulated carcinogen. Traditional bromate control methods use pH depression. While effective, at the DLTWTF, this forces the increased use of more expensive caustic soda over lime for raising the pH of process water. A novel process known as the chlorine-ammonia process was investigated at the bench scale to identify the ideal ratio of chlorine and ammonia to decrease the formation of bromate to ensure regulatory compliance and allow greater use of lime to decrease costs. The best ratio in this study is 0.45 mg/L NH3 to 0.75 mg/L Cl2 which produced 1.09 ppb bromate at a CT of 6.8 min*mg/L, representing a 84% improvement over the control.
25
Tanamati, Fábio Yomei [UNESP]. "Nitrogênio e potássio em cobertura na nutrição e produtividade do alho vernalizado livre de vírus e qualidade do alho minimamente processado." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/146744.
Full textAbstract:
Submitted by FÁBIO YOMEI TANAMATI null (fabioyomei@hotmail.com) on 2016-12-21T18:02:23Z
No. of bitstreams: 1
Tese- Fábio Final.pdf: 1752648 bytes, checksum: f9b77e3ee591fdbadfb4e16551e1bfc3 (MD5)Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-22T13:34:23Z (GMT) No. of bitstreams: 1 tanamati_fy_dr_bot.pdf: 1752648 bytes, checksum: f9b77e3ee591fdbadfb4e16551e1bfc3 (MD5)
Made available in DSpace on 2016-12-22T13:34:23Z (GMT). No. of bitstreams: 1 tanamati_fy_dr_bot.pdf: 1752648 bytes, checksum: f9b77e3ee591fdbadfb4e16551e1bfc3 (MD5) Previous issue date: 2016-06-02
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O alho é uma hortaliça utilizada como condimento e como planta medicinal. O Brasil é um importante produtor/consumidor desta hortaliça, entretanto a produção nacional é insuficiente e portanto importa de quase 60% do alho consumido. Práticas precisas de manejo na produção e pós-colheita precisas podem resultar em economia na produção, aumento da produtividade e qualidade. Entre as práticas de manejo destaca-se a fertilização destaca-se pela influência direta na produção do alho e constituir um dos principais itens do custo de produção. Após a colheita a deterioração do alho minimamente processado (produto com maior valor agregado) pode ser diminuída através do armazenamento em temperatura controlada e atmosfera modificada. Com o objetivo de avaliar e documentar as melhores fontes e doses de nitrogênio e fontes potássio, bem como o melhor método para o armazenamento do alho minimamente processado foram conduzidos três ensaios que serão apresentados em três capítulos, sendo o primeiro intitulado “Fontes de nitrogênio e potássio sob a produtividade e nutrição mineral do alho”, o segundo capítulo intitulado “Produtividade e nutrição mineral do alho sob diferentes doses de nitrogênio e fontes de potássio”, e o terceiro capítulo intitulado “Efeito de diferentes temperaturas e atmosfera modificada sob as características qualitativas do alho minimamente processado”. Concluiu- se a) Diferentes fontes de N e K podem ser combinadas para a obtenção de máxima produção de alho comercial, b) o teor de nutrientes do alho não é influenciado pelas fontes de N e K ao ponto de constituir um fator crítico à produtividade do alho, c) Recomenda-se a dose 80 kg ha -1 de N como forma de obtenção de máxima eficiência do fertilizante e produtiva do alho vernalizado livre de vírus cv. Caçador, d) Não houve diferenças significativas na produção do alho acima da dose 80 kg ha -1 de N, a partir desta dose, o acúmulo de nutrientes no bulbo, de forma geral, foi inferior nos tratamentos K2SO4, e) baixa temperatura e atmosfera modificada contribuem significativamente para a manutenção da qualidade do alho minimamente processado, f) embalagem a vácuo mantém uma atmosfera consistentes em uma maior gama de temperaturas, g) as atmosferas modificadas com alto teor de CO2 podem influenciar a diminuição do valor de L* durante o armazenamento, h) a pungência do alho é mais bem conservada em embalagens a vácuo.
Garlic is used as a spice and as a medicinal plant, Brazil is an important producer/ consumer of this herb, however small domestic production stimulates import of about 60% the garlic consumed in this country. Management practices in the production and accurate post-harvest can result in savings in production and increasing in yield and quality. Among the management practices, fertilization is distinguished by its direct influence on the production of garlic and constitute one of the main cost items of production and postharvest deterioration of minimally processed garlic (product with higher added value) can be reduced by storing in controlled and modified atmosphere temperature. In order to assess and document the best sources and doses of nitrogen and potassium sources, as well as the more suitable storage method for fresh-peeled garlic we carried out three tests that will be presented in three chapters, the first entitled "Yield and mineral nutrition of vernalized virus free garlic in response to nitrogen and potassium sources topdressing" the second chapter entitled "Yield and mineral nutrition of garlic in response to nitrogen doses and potassium sources topdressing”, "Quality changes in fresh-peeled garlic cloves in relation to storage temperatures and modified atmospheres". From these assays we concluded that a) Different sources of N and K may be combined to obtain maximum production of commercial garlic, b) the garlic mineral content is not influenced by the sources of N and K to be considered a critical factor to garlic productivity, c) 80 kg ha -1 of N is the best way to obtain both maximum fertilizer efficiency and productive of virus free vernalizated garlic cultivar Caçador, d) from the dose 80 kg ha -1 , the lowest accumulation of nutrients in the bulb in SKO treatments suggests that potassium sulfate, alleviates possible effects of toxicity caused by excess NH4 + and reduces minerals export for bulb and thereby the ground, e) both low temperature and modified atmosphere significantly contribute to the maintenance of the quality of fresh-peeled garlic, f) vacuum packaging maintains an atmosphere consistent across a wider range of temperatures, g) modified atmospheres with high CO2 content can influence the decrease in L* value during storage, h) garlic pungency is better preserved in vacuum packaging.
26
Fagundes, Agnes Afrodite Sumarelli Albuquerque. "Efeito da acidose metabólica crônica sobre a reatividade vascular da artéria carótida e função cardiorrespiratória de ratos." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/17/17137/tde-08112018-141134/.
Full textAbstract:
Introdução: Os distúrbios ácido-base são comuns na prática médica e podem variar desde uma acidose ou alcalose simples até um distúrbio misto complexo e potencialmente fatal. Em situação de acidose ou alcalose, a permeabilidade iônica e as funções enzimáticas celulares se alteram, acarretando disfunção de diversos órgãos e sistemas. A acidose metabólica (MA), uma condição clínica comum, é causada por uma diminuição no pH do sangue e na concentração de bicarbonato. Pode ocorrer agudamente, com duração de algumas horas a um dia, ou como uma condição crônica, quando o pH normal não pode ser totalmente restaurado. Acidose, como um tipo dominante de distúrbio ácido-base, atualmente, é considerada um fator causador de disfunções cardiovasculares. Poucas pesquisas sobre o efeito da acidose metabólica crônica na função cardíaca, in vivo, estão disponíveis. Assim, é de grande interesse estudar a contratilidade cardíaca in vivo e as mudanças elétricas em resposta a acidose metabólica, além da reatividade vascular em artérias de animais acidóticos. Objetivos: O objetivo do presente estudo foi demonstrar os efeitos da acidose metabólica crônica (AMC) induzida pela administração de cloreto de amônio sobre a função cardiovascular e respiratória, assim como os possíveis mecanismos envolvidos. Metodologia: A AMC foi induzida em ratos Wistar pela substituição de água por uma solução do cloreto de amônio 0,50M ad libitum acrescido de 0,02M por gavagem, durante dez dias. Após dez dias os animais foram agrupados para as demais análises. Foi avaliada a reatividade vascular, frente a diversas drogas vasoativas (Acetilcolina, Fenilefrina, Angiotensina II, Endotelina-1 e ionóforo de cálcio - A23137) utilizando a metodologia de banho de órgão isolado. Algumas curvas dose-resposta foram realizadas na presença de L-NAME. Também foi avaliada a função cardíaca, através do ecocardiograma para pequenos animais, analisando os seguintes parâmetros: débito cardíaco, frequência cardíaca, volume sistólico e encurtamento sistólico e diastólico. A função respiratória foi analisada porResumo pletismografia de corpo inteiro e os parâmetros analisados foram ventilação, volume corrente e frequência respiratória. Além das análises principais citadas acima, foram realizadas também, dosagem de óxido nítrico, análise histológica de rins e dosagens de parâmetros associados a função renal (ureia e creatinina). Resultados: A acidose metabólica crônica (1) potencializou o relaxamento induzido pelo ionóforo de cálcio de maneira dependente do óxido nítrico e não foram observadas alterações para os demais agonistas testados; (2) reduziu o débito cardíaco e volume sistólico, sem alteração na frequência cardíaca; (3) reduziu os níveis de nitrito e nitrato plasmático; (4) aumentou a ventilação e o volume corrente, sem alterações na frequência respiratória e (5) não foram observadas alterações na ureia e creatinina e morfologia dos rins. Conclusão: A acidose metabólica promoveu alterações na reatividade vascular, na função cardíaca e na ventilação pulmonar.Introduction: Acid-base disorders are common in medical practice and can range from simple acidosis or alkalosis to a complex and potentially fatal disorder. In a situation of acidosis or alkalosis, the ionic permeability and the cellular enzymatic functions can change, leading to dysfunction of several organs and systems. Metabolic acidosis (MA), a common clinical condition, is caused by a decrease in blood pH and bicarbonate concentration. It can occur acutely, lasting from a few hours to a day, or as a chronic condition, when normal pH cannot be fully restored. Acidosis, as a dominant type of acid-base disorder, is currently considered a factor causing cardiovascular dysfunction. Few researches on the effect of chronic metabolic acidosis on cardiac function, in vivo, are available. Thus, it is of great interest to study cardiac contractility in vivo and electrical changes in response to metabolic acidosis, in addition to vascular reactivity in arteries from acidotic animals. Aim: The aim of the present study was to demonstrate the effects of chronic metabolic acidosis (CMA) induced by the administration of ammonium chloride on cardiovascular and respiratory function, as well as the possible mechanisms involved. Methods: CMA was induced in Wistar rats by replacing water by solution of ammonium chloride 0.50M ad libitum plus 0.02M per gavage, for ten days. After ten days the animals were grouped for the remaining analyzes. Vascular reactivity was evaluated for several vasoactive drugs (Acetylcholine, Phenylephrine, Angiotensin II, Endothelin-1 and calcium ionophore - A23137) using the isolated organ chamber methodology. Some dose-response curves were performed in the presence of L-NAME. Cardiac function was also evaluated through echocardiogram for small animals, analyzing the following parameters: cardiac output, heart rate, systolic volume and systolic and diastolic shortening. The respiratory function was analyzed by plethysmography of the whole body and the parameters analyzed were ventilation, tidal volume and respiratory rate. In addition to the main analyzes mentioned above, nitric oxide analysis, photomiographs of kidneys and urea and creatinine analysis for renal function evaluation, were also performed. Results:Abstract Chronic metabolic acidosis (1) potentiated calcium ionophore-induced relaxation in a nitric oxide-dependent manner and with no changes for the other agonists tested; (2) reduced cardiac output and systolic volume, with no change in heart rate; (3) reduced nitrite and plasma nitrate levels; (4) increased ventilation and tidal volume without changes in respiratory rate and (5) no changes were observed in urea and creatinine and morphology of the kidneys. Conclusion: Metabolic acidosis promoted changes in vascular reactivity, cardiac function and pulmonary ventilation.
27
Bezerra, Raquel Pedrosa. "Influência do tempo de alimentação e da intensidade luminosa no cultivo de \'Spirulina platensis\' sob alimentação com cloreto de amônio." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/9/9134/tde-15122006-124231/.
Full textAbstract:
A Cianobactéria Spirulina platensis representa uma fonte de proteínas e ácidos graxos que a tornam importante como suplemento alimentar. A fonte de nitrogênio é um nutriente que exerce influência em seu metabolismo. Neste trabalho, observou-se o crescimento de S. platensis e a composição da biomassa obtida, com a utilização de cloreto de amônio como fonte de nitrogênio por processo descontínuo alimentado. Com a utilização de planejamento fatorial, foi realizado o estudo do tempo de alimentação do cloreto de amônio e da intensidade luminosa no cultivo da S. platensis. Os resultados foram avaliados com auxílio da metodologia de superfície de resposta. Menores teores de proteínas e lipídios na biomassa final foram encontrados nos cultivos submetidos a maiores intensidades luminosas. A condição ótima calculada, obtida pela análise estatística, para a obtenção da concentração celular máxima (Xm) e fator de conversão de nitrogênio em células (YX/N) foi encontrada no cultivo sob intensidade luminosa de 13 klux e tempo de alimentação de 17,2 dias. Nessas condições foram obtidos Xm igual 1771 ± 2,3 mg/L e YX/N igual a 5,7 ± 0,17 mg/mg, 3,4% e 4,0% menores que os valores máximos estimados pelo modelo matemático, respectivamente. Maiores produtividades foram obtidas nos cultivos submetidos a maiores intensidades luminosas e menores tempos de alimentação.Cyanobacterium Spirulina platensis represents a protein and fatty acid source that becomes it important as food supplement. The nitrogen source is a nutrient that influences in its metabolism. In this work, it was observed the S. platensis growth and biomass composition using ammonium chloride as nitrogen source in fed-batch process. Using factorial experimental design, it was carried out the study of the ammonium chloride feeding time and light intensity in the S. platensis culture. The results were evaluated by response surface methodology (RSM). Lower protein and lipids contents were found in cell cultures cultivated at higher light intensity. The predictive optimal condition, obtained by statistic analysis, for maximum cellular concentration (Xm) and nitrogen-cell conversion factor (YX/N) was obtained in the culture grown at 13 klux and feeding time of 17.2 days. In these conditions, Xm of 1771 ± 2.3 mg/L and YX/N of 5.7 ± 0.17 mg/mg were obtained. These values are 3.4 % and 4.0 % lower than that ones predicted by mathematical model, respectively. Higher productivities were observed in the culture grown at higher intensity light and lower feeding time.
28
Rogers, Jennifer J. "Assessment of Mussel Declines in the Clinch and North Fork Holston Rivers Using Histological Evaluations of Vital Organs." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/63925.
Full textAbstract:
The Clinch River (CR) and North Fork Holston River (NFHR) contain some of the most diverse freshwater mussel assemblages in the United States; however, both rivers are experiencing declines in mussel populations. The first component of this study used histological evaluations and water quality data to determine whether mussels were negatively impacted in the CR zone of decline (ZD) and to inform future management of freshwater mussels in the river. In the 91 kilometer (km) section from Carbo, Virginia (CRKM 431) downstream to Speers Ferry, Virginia (CRKM 340), referred to as the ZD, mussel density decreased >90% from 1979 to 2014 at key sites such as Semones Island (CRKM 378.3) and Pendleton Island (CRKM 364.2). Laboratory propagated mussels were placed in cages in the river for one year from June 2012 to May 2013 at four sites within the ZD and four sites in reaches where mussel populations remain stable or are increasing, a zone of stability (ZS). The survival, growth and histological results indicated that there are continuing impacts to mussels in the ZD. Research investigating impacts to the ZD and methods to improve water quality in this zone are needed.
The laboratory component of this study examined sublethal effects of potassium (K+), chloride (Cl-), and un-ionized ammonia (NH3-N) on mussel tissues at concentrations relevant to those found in the NFHR. Historical industrial activities at Saltville, Virginia, as well as continued pollution of the NFHR from chemical waste ponds at this location, are believed to be significant contributors to mussel declines. Contaminant seepages from the waste ponds that include Cl-, K+, and NH3-N have been shown to be toxic to adult and juvenile mussels.
A three-month laboratory study was conducted to assess impacts to organ tissues (gills, digestive glands, kidneys, and gonads) of adult Villosa iris exposed to environmentally relevant concentrations of K+ (4 and 8 mg/L), Cl- (230 and 705 mg/L), and NH3-N (0.014 and 0.15 mg/L) using histological evaluations. No detectable differences were observed among the histological endpoints from mussels held in treatments and control (p>0.05). The study design was modified and repeated
using increased concentrations of K+ (8, 16, and 32 mg/L) and Cl- (705, 1410, and 2820 mg/L) for a two-month exposure period. Due to issues with maintaining NH3-N in mussel holding chambers, the second study did not the second study did not include NH3-N exposures. Control mussels in both studies had a higher abundance of lipofuscin in kidneys and degraded cytoplasm in the digestive gland diverticula compared to baseline mussels, indicating that captivity influenced mussel tissues. Future studies are needed to more thoroughly address these captivity effects. Both survival and histological data in the second test showed a significant negative effect of the increased concentrations of Cl- and K+, which were representative of those found at some sites in the NFHR downstream of Saltville, Virginia.Master of Science
29
Guillot, Benjamin. "Etude de procédés de préparation de surface avant nitruration - fiabilité du procédé." Thesis, Paris, ENSAM, 2016. http://www.theses.fr/2016ENAM0068/document.
Full textAbstract:
La nitruration gazeuse de pièces en acier de construction est un procédé thermochimique permettant de générer un gradient de propriétés mécaniques à la surface des pièces par diffusion d’atomes d’azote. Les pièces traitées présentent un fort gradient de contraintes résiduelles et de dureté, optimales pour les applications de transmission de puissance utilisées dans les domaines de l’aéronautique ou l’automobile de compétition. L’enrichissement en azote est issu de la décomposition catalytique de l’ammoniac à la surface des pièces en acier. Cependant, le procédé reste extrêmement sensible à l’état de surface des pièces, qui inclue les caractéristiques géométriques, mécaniques mais également chimique, pouvant inhiber les propriétés de décomposition catalytique ainsi que la diffusion de l’azote. Cette désactivation peut avoir différentes origines, comme l’adsorption d’un élément poison de la réaction ou l’encrassement de la surface des pièces. Le phénomène de désactivation catalytique est étudié depuis quelques dizaines d’années. Cependant, peu de publications sont disponibles au sujet de son application dans le cas particulier de la nitruration d’aciers de construction. Comprendre l’inhibition de la nitruration permettrait d’améliorer la fiabilité industrielle de ce procédé. Afin de répondre à cette demande, une démarche expérimentale, basée sur des études de cas industriels et sur une étude bibliographique, a été mis en place. Une étude de pollution issue de résidus d’huile de coupe, de dépôt de carbone et d’empoisonnement au soufre est proposée. De plus, une démarche expérimentale visant à déterminer l’impact de pollutions mécaniques (état mécanique initial) sur le procédé de nitruration est proposée. Des analyses thermogravimétriques couplées à des observations et à la détermination des propriétés mécaniques générées par nitruration permettent d’approfondir la compréhension de ces phénomènes de désactivation des surfaces nitrurées. Suite à cette étude, la capacité d’activation de surface de trois éléments de préparation in-situ, que sont l’oxydation, l’urée et le chlorure d’ammonium, a été déterminé sur les pollutions précédemment étudiéesThe gaseous nitriding of steel parts is a thermochemical process that generates a mechanical properties gradient at the surface by nitrogen diffusion. The treated parts indicate an important residual stress and hardness gradient, optimized for power transmission applications used in aeronautics and motor sports. The increase of nitrogen concentration is due to the catalytic decomposition of ammonia at the iron-based surface of parts. However, the process is extremely sensitive to the surface state of parts that includes geometrical, mechanical but also chemical properties. This state can inhibit the catalytic decomposition properties and the nitrogen diffusion. This deactivation can have different origins, such as the adsorption of a poisoning element or the fouling of the surface of the parts. The catalytic deactivation phenomenon is studied since decades. However, few publications are available in the case of its application in the specific case of the gaseous nitriding of steel. A better understanding of the nitriding inhibition would improve the reliability of this industrial process. In order to answer this demand, an experimental approach, based on industrial case and bibliographical study, is proposed. A pollution study obtained from machining oil residues, carbon deposit, or sulfur poisoning is proposed. Moreover, an experimental approach, aiming to determine the impact of initial mechanical properties on the nitriding process is proposed. Thermogravimetric analyses coupled to observations and mechanical properties analyses enable to develop the knowledge of the nitrided surfaces deactivation processes. After this study, the surface activation capacity of three in-situ processes, namely oxidation, urea and ammonium chloride, over the previously studied contaminations is determined
30
Bezerra, Roseane Madeira. "Níveis de cloro para codornas japonesas (Coturnix coturnix japonica) nas fases de crescimento e produção." reponame:Repositório Institucional da UFC, 2010. http://www.repositorio.ufc.br/handle/riufc/19047.
Full textAbstract:
BEZERRA, Roseane Madeira. Níveis de cloro para codornas japonesas (Coturnix coturnix japonica) nas fases de crescimento e produção. 2010. 64 f. : Dissertação (Mestrado) - Universidade Federal do Ceará, Centro de Ciências, Departamento de Zootecnia, Programa de Pós-Graduação em Zootecnia. Fortaleza-CE, 2010.Submitted by Eric Santiago (erichhcl@gmail.com) on 2016-08-10T13:32:30Z No. of bitstreams: 1 2010_dis_rmbezerra.pdf: 314058 bytes, checksum: 7b30479bbaf907c17b54b3a8a3526f71 (MD5)
Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-10T15:17:51Z (GMT) No. of bitstreams: 1 2010_dis_rmbezerra.pdf: 314058 bytes, checksum: 7b30479bbaf907c17b54b3a8a3526f71 (MD5)
Made available in DSpace on 2016-08-10T15:17:51Z (GMT). No. of bitstreams: 1 2010_dis_rmbezerra.pdf: 314058 bytes, checksum: 7b30479bbaf907c17b54b3a8a3526f71 (MD5) Previous issue date: 2010
In order to evaluate the effects of chlorine levels in the diet of growing and production of Japanese quails were conducted two experiments in which we assessed the levels of 0.07, 0.12, 0.17, 0.22, 0.27 and 0.32% chlorine. In the first experiment (growing phase), 384 quail on a day-old distributed in a completely randomized design with six treatments of eight replicates of eight birds each. According to the results for the period from 1 to 42 days, with the addition of chlorine level in the diet linearly increased feed intake (g/bird) and weight gain (g/bird) and a linear decrease in the ratio of consumption water/feed intake and excreta moisture. However, feed conversion (g/g), water intake (ml/bird/day), the digestibility of dry matter (CDMS), nitrogen (CDN) and gross energy (GEDC) and the values of metabolizable energy (AME) and apparent nitrogen corrected (AME) of feed were not affected by the level of chlorine still in testing, we found that chlorine levels received by the quails in the growing phase did not significantly affect the performance of phase posture. In the second experiment, 288 quail with seventeen weeks of age were distributed in a completely randomized design with six treatments, eight replicates and six birds per experimental unit. Chlorine levels did not significantly influence feed intake (g/bird/day), water consumption (ml/bird/day), the percentage of stance (%), egg weight (g), the mass of egg (g/bird/day), feed conversion (g/g), the moisture of excreta, the digestibility of dry matter (CDMS), nitrogen (CDN) and gross energy (GEDC), the metabolizable energy apparent (AME) and corrected apparent (AME), Haugh Units, the percentages of albumen, yolk and shell. However, the specific gravity increased linearly with the addition of chlorine in the feed. Considering the results, we can recommend diets for Japanese quails in the growing phase (1 to 42 days) and production made with corn and soybean meal can contain chlorine levels up to 0.32% subject to the parameters performance and egg quality
Com o objetivo de avaliar os efeitos dos níveis de cloro da ração nas fases de crescimento e produção de codornas japonesas foram realizados dois experimentos, nos quais, foram avaliados os níveis de 0,07; 0,12; 0,17; 0,22; 0,27 e 0,32% de cloro. No primeiro experimento (fase de crescimento), 384 codornas com um dia de idade distribuídas em um delineamento inteiramente casualizado, com seis tratamentos de oito repetições de oito aves cada. Conforme os resultados, no período de 1 a 42 dias, com o acréscimo do nível de cloro na ração houve aumento linear no consumo de ração (g/ave) e no ganho de peso (g/ave) e redução linear na relação consumo de água/consumo de ração e na umidade das excretas. Entretanto, a conversão alimentar (g/g), a ingestão de água (ml/ave/dia), os coeficientes de digestibilidade da matéria seca (CDMS), do nitrogênio (CDN) e da energia bruta (CDEB) e os valores de energia metabolizável aparente (EMA) e aparente corrigida para nitrogênio (EMAn) das rações não foram influenciados pelo nível de cloro Ainda nesse ensaio, observou-se que os níveis de cloro recebido pelas codornas na fase de crescimento não afetaram significativamente o desempenho da fase de postura. No segundo experimento, 288 codornas com dezessete semanas de idade foram distribuídas em um delineamento inteiramente casualizado, com seis tratamentos, oito repetições e seis aves por unidade experimental. Os níveis de cloro não influenciaram significativamente o consumo de ração (g/ave/dia), o consumo de água (ml/ave/dia), a percentagem de postura (%), o peso do ovo (g), a massa de ovo (g/ave/dia), a conversão alimentar (g/g), a umidade das excretas, os coeficientes de digestibilidade da matéria seca (CDMS), nitrogênio (CDN) e energia bruta (CDEB), os valores de energia metabolizável aparente (EMA) e aparente corrigida (EMAn), as Unidades Haugh, as percentagens de albúmen, gema e casca. Entretanto, a gravidade específica aumentou linearmente com o acréscimo de cloro na ração. Considerando os resultados, podese recomendar que as rações para codornas japonesas na fase de crescimento (1 a 42 dias) e de produção formuladas com milho e farelo de soja podem conter níveis de cloro de até 0,32% sem prejuízo para os parâmetros de desempenho e qualidade dos ovos.
31
Lorenz, Tom. "Recycling Seltener Erden aus Permanentmagneten und Leuchtstoffabfällen mittels Feststoffchlorierung." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2018. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-237116.
Full textAbstract:
Die 17 Elemente der Seltenen Erden sind Bestandteil vieler Hochtechnologieprodukte, wie Elektromotoren, Spezialgläsern oder Katalysatoren, dennoch liegt die Recyclingrate aus End-of-Life-Produkten derzeit unter 1 %. Mit der Feststoffchlorierung wurde im Rahmen dieser Arbeit eine chemikalien- und kostensparende Methode für den Aufschluss Seltener Erden aus Leuchtstoff- und Magnetabfällen untersucht. Dabei wurden die gemahlenen Edukte mit NH4Cl vermischt und anschließend im Drehrohrofen erhitzt. Durch thermische Zersetzung des NH4Cl wird HCl- und NH3-Gas freigesetzt. Ersteres überführt die Seltenen Erden in die wasserlöslichen Metallchloride, während der NH3 im Prozess als Lösung in 5N-Reinheit anfiel. Die Seltenerdausbeuten lagen je nach Ausgangsstoff zwischen 83,9 und 99,9 %. Die Optimierung der Feststoffchlorierung erfolgte anhand statistischer Versuchspläne, wodurch neue, überraschende Erkenntnisse im Hinblick auf Reaktionsverläufe, Selektivitäten und Prozessführung gewonnen werden konnten.
32
Demoliner, Fernanda. "Formação de biofilme e perfil de resistência antimicrobiana e a sanitizantes de isolados de Pseudomonas spp e Listeria spp. de corte de carne de frango e bubalino." Universidade Federal de Pelotas, 2015. http://repositorio.ufpel.edu.br:8080/handle/prefix/3884.
Full textAbstract:
Submitted by Aline Batista (alinehb.ufpel@gmail.com) on 2018-05-16T14:30:50Z
No. of bitstreams: 2
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Dissertacao_Fernanda_Demoliner.pdf: 883689 bytes, checksum: 17b2361f24d2dcbcf6fa64f2b8eb26cc (MD5)Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-05-16T20:23:53Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Fernanda_Demoliner.pdf: 883689 bytes, checksum: 17b2361f24d2dcbcf6fa64f2b8eb26cc (MD5)
Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-05-16T20:24:07Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Fernanda_Demoliner.pdf: 883689 bytes, checksum: 17b2361f24d2dcbcf6fa64f2b8eb26cc (MD5)
Made available in DSpace on 2018-05-16T20:24:07Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Fernanda_Demoliner.pdf: 883689 bytes, checksum: 17b2361f24d2dcbcf6fa64f2b8eb26cc (MD5) Previous issue date: 2015-03-20
Sem bolsa
A adesão e formação de biofilmes de micro-organismos a superfícies de equipamentos e utensílios no processamento de alimentos resulta em grave problema para a indústria, pois atua como fonte de contaminação do alimento, por serem mais resistentes a ação de sanitizantes e antimicrobianos. O objetivo deste trabalho foi avaliar a capacidade de Pseudomonas spp. e Listeria spp., provenientes de cortes de carnes de frango e de búfalo de frigoríficos e do comércio varejista da região sul do Rio Grande do Sul, de formar biofilmes em superfície de placas de poliestireno e aço inoxidável, bem como verificar a resistência destes a sanificantes e a antimicrobianos. Foram utilizados 69 isolados bacterianos provenientes de cortes de carnes de frango e de búfalo, sendo 19 de espécies de Listeria e 50 de Pseudomonas spp. Os isolados foram avaliados quanto à formação de biofilme em microplacas de poliestireno e em corpos de prova de aço inoxidável. Os isolados formadores de biofilme em aço inoxidável foram testados quanto à ação de sanitizantes: cloro orgânico e quaternário de amônio (200 ppm) e submetidos ao teste de resistência antimicrobiana. A formação biofilme em microplacas de poliestireno foi de 73,7 % para isolados de Listeria spp. e de 32 % para isolados de Pseudomonas spp. Todos os isolados de Listeria spp. e 72% dos isolados de Pseudomonas spp. formaram biofilmes em corpos de prova de aço inoxidável. O quaternário de amônio foi mais eficaz que o cloro orgânico na redução de biofilme de Listeria spp. e Pseudomonas spp. Os isolados pertencentes ao gênero Listeria apresentaram maior resistência à penicilina (94,7 %), à clindamicina (84,2 %), à oxacilina (73,7 %) e à cefepime (57,9 %), sendo que 94,7 % foram resistentes a dois ou mais antimicrobianos. Meropenem foi o antimicrobano menos efetivo para Pseudomonas spp. Também foram encontrados 84% dos isolados de Pseudomonas spp. multirresistentes a antimicrobianos. Conclui-se que os isolados provenientes de cortes de carnes de frango e de bubalino foram formadores de biofilme em poliestireno e aço inoxidável e apresentaram resistência a antimicrobianos, o que confere riscos a saúde do consumidor.
The adhesion and microorganisms biofilm formation on surfaces of equipment and utensilsin food processingresults inserious problem for the industry because it actsas a source of contamination are less resistant to sanitizers and antimicrobial action. The objective of this study was to evaluate the ability of Pseudomonas spp. and Listeria spp. present in chicken and buffalo meat, to form biofilms on the surface of polystyrene plates and stainless steel as well as verify their resistance to sanitizers and antimicrobials. Sixty nine bacterial isolates were used, 19 species of Listeria and 50 species of Pseudomonas spp. The isolates were evaluated to their biofilm formation capacity in polystyrene microplates and stainless steel. Isolated stainless steel biofilm formers were tested for sanitizing action of organic chlorine and quaternary ammonium (200 ppm) and submitted antimicrobial resistance testing. The ability to form biofilmon polystyrene microplates was 73,7 % in isolates of Listeria spp. and 32 % for Pseudomonas spp. All isolates of Listeria spp. and 72 % of Pseudomonas spp. showed the ability to form biofilm on stainless steel specimens. The sanitizing organic chlorine and quaternary ammonium were effective to reduce Listeria spp. and Pseudomonas spp. biofilm formation in stainless steel. Quaternary ammonium was more effective than organic chlorine to reduce Listeria spp. biofilm formation from buffalo meat. Isolates belonging to the Listeria generous showed greater resistance to penicillin (94.7 %), clindamycin (84.2 %), oxacillin (73.7 %) and cefepime (57.9 %), and 94.7 % were resistant to two or more antimicrobial. Meropenem was the less effective antimicroban of or Pseudomonas spp. It was also found that 84 % of isolates of Pseudomonas spp. were multirresistentes to antimicrobianos. The isolates from chicken meat cuts and buffalo were biofilm-forming polystyrene and stainless steel and were resistant to antimicrobials, which gives risk to consumer health.
33
Oliveira, Carlos Rafaell Correia de. "Ingestão de bicarbonato de sódio e cloreto de amônio e seus efeitos sobre o ritmo de prova, desempenho e equilíbrio ácido-base em um teste contrarrelógio de ciclismo de 4km." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/39/39132/tde-25082016-133341/.
Full textAbstract:
Nós determinamos a influência da alcalose e acidose metabólica induzida sobre o ritmo de prova, gasto energético e desempenho durante um teste contrarrelógio de ciclismo de 4 km (TCR). Após um estudo preliminar (N=7) determinando as doses ótimas de cloreto de amônio (NH4Cl), bicarbonato de sódio (NaHCO3) e placebo (carbonato de cálcio, CaCO3), 11 ciclistas amadores realizaram um TCR de 4 km 100 min após ingerirem 0,15 g·kg-1 de NH4Cl, 0,3 g·kg-1 de NaHCO3 ou 0,15 g·kg-1 de CaCO3 (desenho de medidas repetidas, contrabalançado e duplo-cego). Comparado com placebo, a ingestão de NaHCO3 resultou em uma alcalose sanguínea pré-exercício (pH: + 0,06 ± 0,04, [HCO3-]: + 4,7 ± 2,6 mmol?L-1, excess de base: + 4,6 ± 2,4 mmol?L-1, P<0,05), enquanto que o NH4Cl resultou em uma acidose sanguínea (pH: - 0,05 ± 0,04, [HCO3-]: - 5,5 ± 2,9 mmol?L-1, excesso de base: - 5,3 ± 2,5 mmol?L-1, P<0.05), com essas diferenças permanecendo durante todo o teste. Apesar de nenhum desconforto gastrointestinal severo, os participantes adotaram um ritmo de prova significativamente mais conservador em NH4Cl comparado com placebo e NaHCO3, que foi acompanhado por uma redução na taxa de gasto energético anaeróbio (~ -14 %, P<0,05) e menor trabalho anaeróbio total (~ -13 %, P<0,05). Consequentemente, o desempenho foi prejudicado em NH4Cl (~ -7 %) comparado com as demais condições (P<0,05). O lactato plasmático, VCO2 e a PetCO2 foram menores e a VE/VCO2 maior durante o TCR em acidose do que em placebo e alcalose (P<0,05). Entretanto, não houve diferença para essas variáveis entre placebo e NaHCO3 (P<0,05). A acidose metabólica induzida diminuiu o ritmo de prova e o metabolismo anaeróbio, além de prejudicar o desempenho durante um TCR de 4 km, independente de desconforto gastrointestinalWe determined the influence of induced metabolic alkalosis and metabolic acidosis on pacing, energy expenditure and performance during a 4-km cycling time trial (TT). After a preliminary study (N=7) determining the optimal ammonium chloride (NH4Cl), sodium bicarbonate (NaHCO3), and placebo (calcium carbonate, CaCO3) doses, 11 amateur cyclists performed a 4-km TT 100 min after ingesting either 0.15 g·kg-1 of body mass of NH4Cl, 0.3 g·kg-1 of NaHCO3 or 0.15 g·kg-1 of CaCO3 (double-blind, counterbalanced and repeated-measures design). Compared with placebo, the NaHCO3 ingestion resulted in a pre exercise blood alkalosis (pH: +0.06 ± 0.04, [HCO3-]: +4.7 ± 2.6 mmol?L-1, base excess: +4.6 ± 2.4 mmol?L-1, P<0.05), while NH4Cl resulted in a blood acidosis (pH: -0.05 ± 0.04, [HCO3-]: -5.5 ± 2.9 mmol?L-1, base excess: -5.3 ± 2.5 mmol?L-1, P<0.05), with these differences remaining throughout the trial. Despite no gastrointestinal distress, participants adopted a significant more conservative pacing in NH4Cl compared with placebo and NaHCO3, which was accompanied by a reduced anaerobic energy expenditure rate (~ -14 %, P<0.05) and lower total anaerobic work (~ -13 %, P<0.05). Consequently, the performance was less in NH4Cl (~ -7 %) compared with other conditions (P<0.05). Plasma lactate, VCO2 and PetCO2 were lower and the VE/VCO2 higher during the TT in acidosis than in placebo and alkalosis (P<0.05). However, there was no difference for these variables between placebo and NaHCO3 (P>0.05). Induced metabolic acidosis slows pacing, decreases anaerobic metabolism and impairs performance during a 4-km TT, independent of gastrointestinal distress
34
Atifi, Abdelghani el. "Application des composés d'insertion du graphite au stockage chimique de l'énergie thermique." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0072.
Full textAbstract:
Etude de l'action de l'ammoniac sur les composes d'insertion graphite-chlorures metalliques. Suivie de la reaction in sistu en temps reel par diffraction des neutrons. Formation de microcristallites d'ammoniacates au sein du reseau cristallin du graphite. Avantage de cette texture par rapport a l'ammoniacate seul en vue de son application aux procedes de conversion thermochimique de l'energie. L'etude cinetique des reactions mises en jeu
35
Saleem, Saima. "A method of chemical aftertreatment for the reduction of free formaldehyde release of a durable flame retardant finished cotton fabric." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-360.
Full textAbstract:
This thesis aims at developing a method of chemical aftertreatment for reduction of free formaldehyde release of a tetrakis (hydroxymethyl) phosphonium chloride (THPC) urea precondensate, ammonia cured durable flame retardant finished cotton fabric, by preventing the formation of free formaldehyde. Formaldehyde is toxic and carcinogenic. According to the worldwide standards, acceptable limit of free formaldehyde release, for the fabrics that have skin contact, is only 75 ppm (measured by water extraction method). In this research, a cotton fabric flame retardant finished in an industrial plant in Pakistan is used. Fabric is finished by the application of THPC urea precondensate and ammonia cured, oxidized and washed. After finishing, it is not aftertreated with sodium metabisulfite that is a commonly used aftertreatment method for the reduction of free formaldehyde release. Aftertreatment with sodium metabisulfite has various problems that include large number of hot washings and there is an increase in the formaldehyde release during fabric storage. If the fabric has 75 ppm of free formaldehyde, there is often an increase in free formaldehyde release during fabric storage. There is a very limited research on the aftertreatment methods and few reports of application of these aftertreatments on flame retardant fabrics have been published. In this research, two methods of aftertreatments are developed to reduce the free formaldehyde contents to 75 ppm or less. One is the aftertreatment with a combination of resorcinol 1% and diethylene glycol 4%. The other is the combination of resorcinol 1% and boric acid 6%. For both these aftertreatments, ammonium acetate 0.5% is used as a catalyst. Fabric is padded with the solution and then dried at 130̊ C for 8 minutes. After drying, fabric is rinsed with water at 40̊ C. The aftertreatment methods developed in this research have shown a long term effect in keeping the formaldehyde release below 75 ppm during fabric storage that is not available with other conventional aftertreatment methods. These aftertreatment methods have no adverse effect on the flame retardancy of the THPC ammonia cured finished fabric and the fabric is soft as compared to the original flame retardant finished fabric and to the fabric after treated with existing methods. These new developed methods have industrial application because there is no use of any solvent and there is no use of any special equipment for the aftertreatment.
36
Boumaraf, Latra. "Etude des réactions chimiques dans les ammoniacates solides : application du système BaCl2/NH3 à la réfrigération solaire." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0026.
Full textAbstract:
Conception d'un dispositif experimental dans le but d'etudier les proprietes physiques et cinetiques des systemes bacl::(2)/nh::(3) et cacl::(2)/nh::(3). Mesures de vitesses de desorption et d'absorption. Modele d'optimisation des processus et experimentation d'un prototype de refrigeration a capteur solaire plan
37
PIRES, LUIZ E. B. "Avaliação e identificação da toxidade (Toxicity Identification Evaluation - TIE) do efluente líquido do pólo industrial de Belford Roxo, RJ, e sua contribuição na qualidade das águas do curso inferior do Rio Sarapuí, sub-bacia do Rio Iguaçú, bacia da Baía da Guanabara, RJ, Brasil." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11476.
Full textAbstract:
Made available in DSpace on 2014-10-09T12:52:19Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:00:49Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
38
Megda, Michele Xavier Vieira. "Transformações do N derivado do fertilizante no solo e a eficiência de utilização pela cultura da cana-de-açúcar cultivada em solo coberto por palha." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-23082013-163619/.
Full textAbstract:
A adição ao solo de resíduo vegetal de elevada relação C/N no sistema \"cana crua\", afeta o equilíbrio entre os processos de entrada e saída do N no sistema solo-planta-atmosfera. Assim, a presença da palhada modifica o agrossistema fazendo-se necessários ajustes no manejo da fertilização nitrogenada. Nesse sentido, quatro estudos foram desenvolvidos com os seguintes objetivos: (i) Avaliar as características produtivas e nutricionais da cultura da cana-de-açúcar de modo a identificar a fonte e a dose de N de maior eficiência agronômica; (ii) Quantificar a recuperação do N proveniente do fertilizante pela cana-de-açúcar; (iii) avaliar o potencial de inibição do íon cloreto na nitrificação no solo; (iv) avaliar as taxas de mineralização e imobilização do N-fertilizante e a sua interação com o Nnativo do solo. Em campo, foi conduzido um experimento em Latossolo Vermelho distróficocom cana-de-açúcar. O delineamento experimental foi o de blocos casualizados, com quatro repetições e nove tratamentos, com as fontes nitrogenadas: sulfato de amônio, YaraBela NitromagTM, nitrato de amônio e ureia na dose de 100kg ha-1 de N, cloreto de amônio, nas doses de N: 50, 100, 150 e 200 kg ha-1, e controle. Foram instaladas microparcelas com aplicação das fontes marcadas no isótopo 15N na dose de 100 kg ha-1 de N. Os fertilizantes nitrogenados foram aplicados manualmente, sobre a palhada. Posteriormente, amostras do solo coletadas previamente foram incubadas aerobiamente por um período de 21 dias. O delineamento experimental foi o inteiramente casualizado com quatro repetições e os tratamentos constaram da combinação de sulfato de amônio ou cloreto de amônio, na dose de 100 mg kg-1 de nitrogênio, com cloreto de potássio na dose de 100 ou 200 mg kg-1 de cloro. Avaliou-se, também, doses de cloreto de amônio (50, 100 e 200 mg kg-1 de N). As formas de N-mineral foram determinadas por meio de sistema de análise por injeção em fluxo. Amostras de solo foram, também, incubadas aerobiamente por um período de 20 semanas. O delineamento experimental foi o inteiramente casualizado com três repetições e seis tratamentos, constituindo-se um fatorial 3x2 (Namídico, N-amoniacal ou sem N versus com ou sem resíduo de cana). As fontes nitrogenadas (enriquecidas com 2% em átomos de 15N) foram aplicadas superficialmente no solo na dose de 100 mg kg-1 de N e o resíduo de cana-de-açúcar incorporado na dose de 5,2 g kg-1. O fornecimento de doses de N na forma de cloreto de amônio resultou em decréscimo de produtividade de colmos e açúcar. As fontes nítrico/amoniacais promoveram maior atividade da enzima redutase do nitrato nas folhas da cana-de-açúcar, porém, não apresentaram influência no acúmulo total de N. O aproveitamento do N-fertilizante pela cana-de-açúcar foi da ordem de 60% nos estádios iniciais, reduzindo-se para aproximadamente 20% próximo à fase de maturação. O íon cloreto reduziu a concentração de nitrato no solo devido a ação do ânion na reação de nitrificação. A incorporação de resíduo de cana-de-açúcar ao solo promoveu maiores taxas de imobilização do N e a aplicação de sulfato de amônio resultou em maior mineralização do N nativo do solo comparado a ureia.The addition of plant residue with high C/N ratio to the soil in a \"green cane\" system affects the balance of input/output processes of N in a soil-plant-atmosphere system. Thus, the presence of straw modifies the agroecosystem requiring adjustments in management of nitrogen fertilization. Accordingly, four studies were developed to: (i) evaluate the nutritional and productive characteristics of sugarcane crops to identify the source and N rates of greater agronomic efficiency; (ii) quantify the sugarcane N recovery from fertilizers; (iii) assess the potential inhibition of chloride ion in reaction to soil nitrification, (iv) evaluate mineralization and immobilization rates of fertilizer-N and their interaction with the native soil N. We conducted a field experiment on a Typic Hapludox with sugarcane, in the 2009/2010 harvest. The experimental design was a randomized block with four replications and nine treatments with nitrogen sources: ammonium sulfate, YaraBela NitromagTM, ammonium nitrate and urea at 100 kg N ha-1, ammonium chloride at N doses: 50, 100, 150 and 200 kg ha-1 and control. Microplots were installed with application of nitrogen sources labeled 15N at 100 kg N ha-1. Nitrogen fertilizers were applied manually over straw. Subsequently, previously collected soil samples were incubated aerobically for 21 days. The experimental design was completely randomized with four replications and the treatments consisted of ammonium sulfate or ammonium chloride at 100 mg N kg-1 with potassium chloride at a chlorine dose 100 or 200 mg kg-1. We also evaluated doses of ammonium chloride (50, 100, and 200 mg N kg-1). Forms of mineral-N were determined by Flow Injection Analysis (FIA) system. Soil samples were incubated aerobically for 20 weeks. The experimental design was completely randomized with three replications and six treatments, comprising a 3x2 factorial (amidic-N, ammonium- N or without N versus with or without cane residue). Nitrogen sources (enriched with 2 atom% 15N) were applied to the soil surface at a N dose of 100 mg kg-1 and residue sugarcane incorporated at 5.2 g kg-1. The N supply in ammonium chloride form resulted in decreased yield of sugar and stalks. Nitric-ammonium sources promoted higher activity of nitrate reductase in sugarcane leave; however, they did not affect total N accumulation. The sugarcane recovery of fertilizer-N was approximately 60% in early stages, dropping to about 20% near the maturity stage. The chloride ion reduced nitrate concentration in soil due to the anion action in the nitrification reaction. The sugarcane residue incorporation to the soil showed higher N immobilization rates and the use of ammonium sulfate resulted in higher N mineralization rates of native soil N compared to urea.
39
Pokapanich, Wandared. "Solvent–Solute Interaction : Studied by Synchrotron Radiation Based Photo and Auger Electron Spectroscopies." Doctoral thesis, Uppsala universitet, Yt- och gränsskiktsvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-138749.
Full textAbstract:
Aqueous solutions were studied using photoelectron and Auger spectroscopy, based on synchrotron radiation and a liquid micro-jet setup. By varying the photon energy in photoelectron spectra, we depth profiled an aqueous tetrabutylammonium iodide (TBAI) solution. Assuming uniform angular emission from the core levels, we found that the TBA+ ions were oriented at the surface with the hydrophobic butyl arms sticking into the liquid. We investigated the association between ions and their neighbors in aqueous solutions by studying the electronic decay after core ionization. The (2p)−1 decay of solvated K+ and Ca2+ ions was studied. The main features in the investigated decay spectra corresponded to two-hole final states localized on the ions. The spectra also showed additional features, related to delocalized two-hole final states with vacancies on a cation and a neighboring water molecule. These two processes compete, and by comparing relative intensities and using the known rate for the localized decay, we determined the time-scale for the delocalized process for the two ions. We compared to delocalized electronic decay processes in Na+, Mg2+, and Al3+, and found that they were slower in K+ and Ca2+, due to different internal decay mechanisms of the ions, as well as external differences in the ion-solute distances and interactions. In the O 1s Auger spectra of aqueous metal halide solutions, we observed features related to delocalized two-hole final states with vacancies on a water molecule and a neighboring solvated anion. The relative intensity of these feature indicated that the strength of the interaction between the halide ions and water correlated with ionic size. The delocalized decay was also used to investigate contact ion pair formation in high concentrated potassium halide solutions, but no concrete evidence of contact ion pairs was observed.Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 726
40
Allan, Shawn Michael. "Reactive replacement and addition of cations in bioclastic silica and calcite." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/19239.
Full textAbstract:
Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2005.Committee Chair: Kenneth Sandhage; Committee Members: Joe Cochran, Robert Snyder and Tom Sanders. Part of the SMARTech Electronic Thesis and Dissertation Collection.
41
Nyström, Stephanie, and Elias Bäckström. "Ämnestransport i Tomtaåns avrinningsområde : Inverkan av Hovgårdens avfallsanläggning och diffusa utsläpp." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-296195.
Full textAbstract:
The chemistry of a stream is the result of different transport routes of the precipitation and the processes it undergoes in the catchment area to the stream. The transport route can involve natural processes in the ground, called diffuse sources, or some more anthropogenic sources titled point sources. In the stream, this chemistry is affected by dilution and different sources and sinks of substances. From Hovgårdens waste facility, a point source situated in Tomtaåns water catchment (20 km NE of Uppsala), waste water is released in the nearby Hovgårdsbäcken stream, bringing various metals, salts and nutrient salts. This is then transported to Lissån stream and further on to Tomtaån stream. Before connecting to Lissån, Tomtaån flows through a rural landscape without known larger point sources. This project has two purposes, one is to investigate if substance concentrations in the water changes on its transport along Hovgårdsbäcken, Lissån and Tomtaån streams and why. The other is to determine whether the mass transport from Tomtaån stream is significant for the water chemistry compared to Lissån stream. This project is based on substance concentrations measured by Uppsala Vatten AB from 2009-2014 and the writers’ own measurements from spring of 2016. The substances concerned in this project are N-tot, P-tot, NH4+, PO43-, Fe, SO42-, NO3-. The samplings made by Uppsala Vatten AB does not include Tomtaån upstream the inflow from Lissån. To obtain the size of the mass transport of Tomtaån, modelled substance concentrations along with surface types from GIS have been used. A mass balance was then calculated. The reliability of these values are then discussed. The own measurements included discharge measurements and water sampling to carry out analysis of pH, alkalinity as well as anions Cl-, SO42- and NO3-. The results showed that for Fe, P-tot and PO43-, the values were peaking after the inflow of Lissån to Tomtaån, meaning that these ones come in higher values from Tomtaån than Hovgården. N-tot, NH4+ and SO42- decrease in concentration along the transport which indicates the opposite for Fe, P-tot and PO43-. The mass transport calculated with the modelled values indicates an absurd deficit, which brings the conclusion that these are not reliable.Ett vattendrags kemi är ett resultat av nederbördens olika transportvägar och dess processer i avrinningsområdet. Transportvägen kan innefatta naturliga processer i mark, så kallade diffusa utsläpp, och mer antropogena källor som har en bestämd utsläppspunkt, vilka benämns som punktkällor. Väl i vattendraget påverkar utspädning, källor och sänkor ämnenas halter. Från Hovgårdens avfallsanläggning, en punktkälla som ligger i Tomtaåns avrinningsområde (2 mil nordost om Uppsala), rinner avfallsvatten ut i den närliggande Hovgårdsbäcken med en rad olika typer av metaller, salter och närsalter. Detta transporteras vidare till Lissån vars flöde går ihop med Tomtaån. Tomtaån rinner innan sammanflöde med Lissån genom ett jordbrukslandskap utan större kända punktkällor men där diffusa utsläppskällor kommer till uttryck. Projektet har två syften, det ena är att undersöka om ämneshalterna i vattnet på sin transport längsmed Hovgårdsbäcken, Lissån och Tomtaån förändras och varför. Det andra är att slå fast om masstransporten från Tomtaån är betydande för vattenkemin jämfört med Lissån. Till grund för projektet ligger ämneshalter tagna vid olika punkter av Uppsala Vatten AB år 2009-2014 respektive prover tagna av författarna våren 2016. Ämnen som ligger i fokus är; N-tot, P-tot, NH4+, PO43-, Fe, SO42-, NO3-. Uppsala Vattens provtagningar innefattar inte Tomtaån uppströms. För att få fram storleken på Tomtaåns masstransport, har istället schablonvärden och markanvändningsareor tagna ur GIS använts. Med dessa schablonvärden och de empiriskt uppmätta halterna från Uppsala Vatten har massbalansberäkningen sedan gjorts. Vi kommer föra en diskussion om denna metod var tillförlitlig eller ej. Av författarna mättes vattenföring och vattenprover togs, vilka analyserades för pH och alkalinitet såväl som anjonerna: Cl-, SO42- and NO3-. Resultatet visade att ämneshalterna för Fe, P-tot and PO43- var högst efter Lissåns inflöde med Tomtaån. Vilken betyder att vattenkemin påverkas mer av Tomtaån än Hovgården. Resterande ämnen minskar i halt längsmed transporten, Hovgården bidrar med högst ämneshalt och Tomtaån påverkar vattenkemin genom utspädning. Masstransporten beräknad med schablonvärden indikerar ett massivt orimligt underskott, bedömningen är att schablonhalter ej är tillförlitliga.
42
Ralaiarisoa, Maryline. "Electronic properties of hybrid organic-inorganic perovskite films: effects of composition and environment." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20194.
Full textAbstract:
Der Schwerpunkt der vorliegenden Arbeit liegt in der Charakterisierung der elektronischen Eigenschaften von hybriden organisch-anorganischen Perowskit (HOIP)-Schichten während der Schichtbildung und in verschiedenen Umgebungen mittels Photoelektronenspektroskopie (PES). Insbesondere wird der Methylammonium-Blei-Iodid-Chlorid-Perowskit (MAPbI3-xClx) untersucht.
Als erstes werden Änderungen in den elektronischen Eigenschaften, der Zusammensetzung, sowie der Kristallstruktur mittels PES, Flugzeit-Sekundärionenmassenspektrometrie, sowie Röntgendiffraktometrie mit streifendem Einfall analysiert. Die Resultate weisen auf die entscheidende Rolle von Chlor im texturierten Wachstum der Perowskitschicht hin. Die auskristallisierte Perowskitschicht weist eine stärkere n-Typ Eigenschaft auf, welche auf die Änderung der Zusammensetzung während der Schichtbildung zurückgeführt werden kann. Außerdem beweisen die Ergebnisse eindeutig die Ablagerung von Chlor an der Grenzfläche zwischen der Perowskitschicht und dem Substrat. Zweitens werden die separaten Einflüsse von Wasser, Sauerstoff, und Umgebungsluft auf die elektronischen Eigenschaften von MAPbI3-xClx-Schichtoberflächen untersucht. Bereits geringste Wassermengen ähnlich wie im Hochvakuum oder in inerter Umgebung können eine reversible Reduzierung der Austrittsarbeit hervorrufen. Höherer Wasserdampf-Partialdruck führt zu einer Verschiebung des Valenzbandmaximums (VBM) weit vom Fermi-Niveau, sowie zu einer Reduzierung der Austrittsarbeit. Im Gegensatz dazu führt eine Sauerstoffexposition zu einer Verschiebung des VBM in Richtung des Fermi-Niveaus und zu einer Steigerung der Austrittsarbeit. Analog kommt es zu einer Verschiebung von bis zu 0.6 eV bei einer Exposition gegenüber Umgebungsluft, was den vorwiegenden Einfluss von Sauerstoff demonstriert.
Die vorliegenden Untersuchungen betonen den kritischen Einfluss der Schichtbildung, der Zusammensetzung, sowie der Umgebungsbedingungen auf die elektronischen Eigenschaften von HOIP.The present thesis aims at characterizing the electronic properties of solution-processed hybrid organic-inorganic perovskites (HOIPs) in general, and the HOIP methyl ammonium (MA) lead iodide-chloride (MAPbI3-xClx) films, in particular, at different stages, namely from its formation to its degradation, by means of photoelectron spectroscopy (PES). Firstly, the formation of MAPbI3-xClx films upon thermal annealing is monitored by a combination of PES, time-of-flight secondary ion mass spectrometry, and grazing incidence X-ray diffraction for disclosing changes in electronic properties, film composition, and crystal structure, respectively. Overall, the results point to the essential mediating role of chlorine in the formation of a highly textured perovskite film. The film formation is accompanied by a change of composition which leads to the film becoming more n-type. The accumulation of chlorine at the interface between perovskite and the underlying substrate is also unambiguously revealed. Secondly, the separate effects of water and oxygen on the electronic properties of MAPbI3-xClx film surfaces are investigated by PES. Already low water exposure – as encountered in high vacuum or inert conditions – appears to reversibly impact the work function of the film surfaces. Water vapor in the mbar range induces a shift of the valence band maximum (VBM) away from the Fermi level accompanied by a decrease of the work function. In contrast, oxygen leads to a VBM shift towards the Fermi level and a concomitant increase of the work function. The effect of oxygen is found to predominate in ambient air with an associated shift of the energy levels by up to 0.6 eV. Overall, the findings contribute to an improved understanding of the structure-property relationships of HOIPs and emphasize the impact of least variation in the environmental conditions on the reproducibility of the electronic properties of perovskite materials.
43
Pires, Luiz Eduardo Botelho. "Avaliação e identificação da toxicidade (Toxicity Identification Evaluation - TIE) do efluente líquido do pólo industrial de Belford Roxo, RJ e sua contribuição na qualidade das águas do corso inferior do Rio Sarapuí, sub-bacia do Rio Iguaçú, Bacia da Baía da Guanabara, RJ, Brasil." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-16052012-080425/.
Full textAbstract:
A qualidade dos efluentes líquidos do Pólo Industrial de Belford Roxo e das águas do Rio Sarapuí foram avaliadas por meio de ensaios de toxicidade aguda com Daphnia similis, Ceríodaphnia dúbia e Danio rerio e ensaios de toxicidade crônica com Ceriodaphnia dúbia e Selenastrum capricornutum. Em associação ao monitoramento ecotoxicológico, foram realizados os procedimentos de Avaliação e Identificação da Toxicidade - AIT (Toxicity Identification Evaluation - TIE) os quais possibilitaram a identificação dos agentes tóxicos para as duas matrizes. Para o efluente, foi identificado o íon cloreto como principal agente tóxico, complementado por efeitos aditivos de metais, amônia e sulfeto. As águas do Rio Sarapuí apresentam os nutrientes fósforo e nitrogênio como principais agentes tóxicos, com toxicidade aditiva de metais, amônia e sulfeto. Embora a Estimativa de Impactos Ambientais a partir dos dados de toxicidade do efluente sugira impactos mínimos por parte do lançamento de efluentes do Pólo no compartimento água superficial, a qualidade das águas desse rio já apresenta por si só um impedimento à manutenção da vida aquática. O constante lançamento de esgoto não tratado compromete a qualidade das águas do rio Sarapuí, culminando num quadro de completa degradação devido ao aumento da concentração de nutrientes e matéria orgânica, que acaba por inviabilizar o correto equilíbrio desse ecossistema e suas interações ecológicas naturais.The quality of Belford Roxo Industrial Plant effluent and water from Sarapuí River were evaluated with Daphnia similis, Ceriodaphnia dubia and Danio rerio acute and chronic toxicity tests. In association with the ecotoxicological monitoring, the Toxicity Identification Evaluation procedure were performed and the identification of the toxic compounds was possible. The Chloride ion was identified as the major toxic compound in the effluent with additional effects of Metals, Ammonium and Sulfide. For the Sarapuí River, the compounds of Phosphorus and Nitrogen were identified as the major toxic compounds with addictive effects of Metals, Ammonium and Sulfide. Although the environmental impact estimation based on the effluent toxicity suggests a minor impact on the water quality of Sarapuí River, this was already sufficiently contaminated to make impracticable the establishment of an aquatic community. The constant discharge of untreated sludge promotes the eutrophication of this water body and makes impossible the equilibrium of this ecosystem.
44
Hassiotis, Panayiotis. "The production of nitrous oxide by chloride catalysed decomposition of ammonium nitrate in aqueous solutions." Thesis, 2015. http://hdl.handle.net/10539/16738.
Full text
45
Kennedy, Matthew joseph. "Influence of varying levels of ammonium chloride on urine pH and specific gravity, overall feed conversion, and water consumption in mature wether goats." 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2641.
Full textAbstract:
The objective of this study was to evaluate the effect of orally administered
ammonium chloride (NH4CL) on pH and specific gravity of urine, overall gain, and
water consumption in mature wethers on a grower/finisher ration. Obstructive
urolithiasis, or urinary calculi, is a common problem in sheep and goat production
systems utilizing a high grain diet, particularly one high in magnesium. Maintaining
animals on a 70 to 90% concentrate ration is most conducive to the formation of urinary
calculi. Boer cross wethers (n = 24) were stratified by body weight and randomly
assigned within strata to one of three treatment groups. Wethers were placed on a
common diet containing 2% NH4Cl during the three week collection period. Treatment
consisted of daily oral dosages of 0g NH4CL (CON), 5.85 g NH4CL (TRT 1), or 13.8g
NH4CL (TRT 2). Urine collected from TRT2 tested more acidic on the second and
fourth collections before coming back linear constant with both the control (CON) and
TRT1 . There was no effect of treatment (P < 0.001) on specific gravity of urine.
Weight gain was greater (P < 0.01) in TRT1 (4.15 kg) and TRT2 (4.48 kg) as compared
to CON wethers (2.95 kg). Water consumption was the most variable of all investigated objectives; all groups began with a linear increase for the first 4 d. Treatment 2 (P <
0.001) then showed significant increase at collections 2 and 4. Treatment 1 stayed more
linear with the control with minimal increases (P < 0.001) occurring at periods of more
acidic urine.
This study indicates that administration of NA4Cl had minimal effect on urine
pH, water consumption, and overall gain, but no effect on specific gravity.
46
Bull, Jennifer Patricia. "Immunoassays for two quaternary ammonium compounds, benzyldimethyldodecylammonium chloride (BDD12AC) and didecyldimethylammonium chloride (DDAC)." Thesis, 1997. http://hdl.handle.net/2429/7604.
Full textAbstract:
A competitive enzyme-linked immunosorbent assay (CELISA), based on polyclonal
antibodies, was developed to measure benzyldimethyldodecylammonium chloride
(BDD₁₂AC), a component of benzalkonium chloride (BAK). The polyclonal antibodies
recognized free benzyldimethyldodecylammonium bromide (BDD₁₂AB), with a 50%
inhibition (IC₅₀) of 0.66 µg/mL and a detection limit of 0.043 µg/mL. The two other
components of BAK, benzyldimethyltetradecylammonium chloride (BDT₁₄AC) and
benzyldimethylhexadecyl-ammonium chloride (BDH₁₆AC), as well as other
alkyldimethylbenzylammonium compounds (ADBACs), were recognized to varying degrees
by the antibodies. The antibodies also recognized a commercial BAK compound (77% C₁₂:
23% C₁₄). The antibodies cross-reacted minimally with other compounds such as fatty acids
and alcohols, amino acids, amines, and short-chain quaternary ammonium compounds.
CELISA and HPLC were used to quantify BDD₁₂AB and BAK (Aldrich) spikes in milk
solutions. BDD₁₂AC was also measured in five commercial products containing BAK, using
both analyses. HPLC analysis correlated well with CELISA analysis for these commercial
products.
CELISAs were also developed for didecyldimethylammonium chloride (DDAC)
using three novel haptens. The three resulting antisera recognized DDAC to different
degrees, with IC₅₀'s ranging from 0.05 µg/mL to 17.2 µg/mL. Cross-reactivity with
compounds representing DDAC's different epitopes were observed for the three sera at
varying degrees. The antisera also showed varying degrees of susceptibility to detergent
effects, where one serum cross-reacted more with sodium dodecyl sulfate (SDS) than DDAC. Performance of one of the sera raised against DDAC was a marked improvement
over a previously described anti-DDAC serum, produced by Chen et al. (1995). This new
antiserum could be used to detect DDAC in environmental samples since the IC₅₀ is 50 ppb,
well under the discharge limit of 700 ppb.
47
Sprake, Philippa May. "The Effect of Continuous and Pulse Dose Ammonium Chloride Regimens on the Urine pH of Goats." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11515.
Full textAbstract:
Ammonium chloride (NH4Cl) has been the primary preventive modality for struvite urolithiasis in goats. This study investigated the effect of continuous and pulse dose NH4Cl therapeutic regimens on urine pH in ten goats.
The initial regimen (feed additive) consisted of 0.007% NH4Cl as a feed additive. Following this week long regime, the two treatment regimens were designed as a standard ten goat cross-over design. The first treatment regimen (continuous) consisted of daily administration of a titrated dosage of NH4Cl for ten days, followed by four days without treatment. The third treatment regimen (pulse) used daily administration of a titrated dose of NH4Cl for three consecutive days followed by four days without treatment for three treatment periods. Ammonium chloride dosages were titrated to result in a urine pH of < 6.5 (target level) prior to commencing treatment regimens. Urine pH was evaluated once daily during feed additive regimen and twice daily during the treatment regimens.
A Bayesian methodology was used to determine the daily odds ratios for production of target urine pH during treatment regimens. The odds ratios were also calculated between pulse dosages during the pulse regimen. The feed additive regimen did not result in target urine pH within 7 days. Treatment with the continuous regimen resulted in target pH, however, pH returned to >6.5 within five days, (odds ratio 0.23-1.56 at Treatment Time 10). The odds ratios for each pulse period of the pulse dose regimen were 2.20-7.45, 0.41-1.68 and 1.59-5.62 respectively. The results of this study indicate that variability in response to therapy warrants titrating individual dosages of NH4Cl, continuous therapy results in a loss of effectiveness, and pulse dosage is effective in repeatedly producing a urine pH of <6.5.
48
Huang, Sing-Hao, and 黃星豪. "Effect of Ammonium-nitrogen, Sulfate, and Chloride on biohydrogen production." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/64637805411401742180.
Full textAbstract:
碩士國立高雄第一科技大學
環境與安全衛生工程所
97
Nutrients provide necessary elements for microbial metabolism. As the chemical nutrients exceed certain concentrations, they cause inhibition even toxicity to microorganisms. Three popular substances, NH4+、SO42- and Cl-, were selected for the investigation of their mutual effect on biohydrogen production This study was conducted by batch experiments which were operated in a constant temperature room controlled at 41±1℃. Molasses at 10 % was used as feed substrate and cultivated sludge was employed as seeding material. The initial NH4+、SO42- and Cl- concentration were in the range of 0 to 30,000 mg/L with five concentrations for each substance. pH was controlled at 7 for SO42- and Cl- while NH4+ was studied at pH between 5 to 9. Full Factorial Central Composite Design Method was applied for experimental design. Grompertz equation, multiple regression, and inhibition model were used for data analyzing and predicting effect of NH4+、SO42- and Cl- on biohydrogen production . For the effect of combination of two substances, the results based on kinetic and response analysis indicated that stimulation should happen under the following four conditions: NH4+ less than 1,000 mg/L and SO42- greater than 3,000 mg/L, Cl- less than 400 mg/L and SO42- greater than 3,500 mg/L, SO42- less than 1,500 mg/L and Cl- greater than 1800 mg/L, and NH4+ in the range of 700 to 1,500 mg/L while Cl- between 600 and 1300 mg/L However, inhibition should happen under the following four conditions: NH4+ in the range of 200 to 800 mg/L as SO42- around 1500 mg/L, Cl- less than 300 mg/L and SO42- less than 1,500 mg/L, Cl- greater than 1,700 mg/L and SO42- greater than 4,500 mg/L, and NH4+ greater than 2,500 mg/L and Cl- greater than 2,500 mg/L. Overall, it demonstrated that SO42- had more impact than either NH4+ or Cl- and Cl- showed the least effect among these three substances. Consistently, the results based on the non-competitive and non-linear inhibition model analysis indicated that the specific hydrogen production rate decreased reversely with SO42- while NH4+ greater than 1,800 mg/L or Cl- greater than 3,500 mg/L. As to the effect of combination of the three substances, the results based on the analysis model implied that the microbial activity increased with SO42-. It should be caused by mutual balance among coexisting microorganisms.
49
Wang, Chun-Chieh, and 王俊傑. "The Effect of Adding Ammonium Chloride on Special Phosphate Optical Glass." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/87437268318715686560.
Full textAbstract:
碩士清雲科技大學
電機工程所
100
This experiment uses 5Na2O-5MgO-5Al2O3-5La2O3-15ZnO-60P2O5-5Yb2O3 phosphate glasses doped with 1%, 3%, 5% and 7% of NH4Cl that are specifically used in optics field as the main body, and investigates characteristic changes in melted optical phosphate glasses. In this study, structure of glass was discussed and its physical/chemical property, thermal property, optical property and spectroscopic property were determined. This study discovers that when NH4Cl is added, characteristics of Na2O-MgO-Al2O3-La2O3-ZnO-P2O5-Yb2O3 as the main body main be effectively adjusted. When NH4Cl is between 3 – 5 %, refractive index is the highest and dissolution rate is the lowest. In other words, when 3 – 5 % of NH4Cl are added, it will make the structure of Na2O-MgO-Al2O3-La2O3-ZnO-P2O5-Yb2O3 glass system more complete, refractive index will reach 1.5476 and dissolution rate will be reduced to 1.39(*10-6 g/cm2-hr).We successfully add NH4Cl that allow properties of system to be adjusted. The result may be used as a reference for optical glass development in the future.
50
Silva, Maria Antónia Sousa Correia da. "Microparticles Loaded with Benzyldimethyldodecyl Ammonium Chloride to Control Adapted Resistant Bacteria." Dissertação, 2016. https://hdl.handle.net/10216/89618.
Full text