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1
Mokhtar, Mohd Noriznan. "Biocatalytic Production, Preparation and Characterization of Large-ring Cyclodextrins." Doctoral thesis, Universitätsbibliothek Chemnitz, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200900431.
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Cyclodextrins (CD) are cyclic oligosaccharides composed of six to more than sixty
glucose units. Large-ring cyclodextrins (LR-CD) are novel CD comprised of more than eight
glucose units with cavity structures and sizes different from that of commercially available
CD6 – CD8. LR-CD may offer unique molecular recognition properties and can be produced
biocatalytically from starch using cyclodextrin glucanotransferase (CGTase, E.C. 2.4.1.19) in
a short reaction time. LR-CD were isolated from glucose, CD6 – CD8 and other compounds by
complexation of CD6 – CD8 as well as precipitation techniques. The yield of LR-CD (degree
of polymerization from 9 to 21) was optimized using central composite design. Addition of
polar organic solvents to the synthesis resulted in higher yields of LR-CD. LR-CD composed
of 9 to 21 glucose units were successfully separated using reversed-phase of ODS-AQ
chromatography and normal-phase of polyamine II chromatography. Maintaining optimized
reaction conditions aided in a high yield of CD9; it could be separated with reasonable yield
using a single step of polyamine II chromatography. A co-grinding method helped to obtain
higher solubilization levels of glibenclamide, vitamin A acetate and vitamin D3 in CD13, CD10
and CD11, respectively when compared to other CD. Vitamin K1 was solubilized in distilled
water with CD6 – CD13 using a co-precipitation method. When compared with other CD, CD9
was seen to be the best solubilizer. The analysis of complexes using ESI MS showed
spironolactone and glibenclamide complexed with CD9 and CD13, respectively.
2
Hasson, Dhari A. "Mixture preparation and combustion in spark ignition engines." Thesis, Aston University, 1986. http://publications.aston.ac.uk/11867/.
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Janiak, T., I. Cieszykowska, T. Barcikowski, K. Jerzyk, and M. Mielcarski. "Preparation of metallic target of 100Mo for production of 99mTc in cyclotron." Helmholtz-Zentrum Dresden - Rossendorf, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-164572.
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Introduction
Technetium-99m, the daughter of 99Mo is the most commonly used radioisotope in nuclear medicine [1–2]. Current global crisis of 99Mo supply, aging of nuclear reactors and staggering costs force the search for alternative sources of 99mTc. Radioisotope Centre POLATOM joined the IAEA Coordinated Research Project on “Accelerator-based Alternatives to Non-HEU Production of 99Mo/99mTc”. The planned outcome of this project is development of 99mTc production method using the reaction of 100Mo(p,2n)99mTc [3] in Polish cyclotron.
This work presents the results concerning preparation of 100Mo target for irradiation with protons.
Material and Methods
The manufacturing of Mo target was performed using pressing of molybdenum powder into pellets and its sintering in hydrogen atmosphere at 1600 oC [4]. For this purpose a tantalum and stainless steel plates were used as support. Several pellets using molybdenum powder with particles size of 2 µm in diameter were pressed at different values of pressure.
Results and Conclusion
The optimized parameters of pressing molyb-denum pellets with various sizes are given in TABLE 1. It was found that the pellets did not adhere neither to the tantalum nor stainless steel plates but they conducted electricity very well. Pellets prepared with higher pressure were more mechanically resistant, however application, even the highest used pressure did not ensure its satisfactory stability.
In order to improve mechanical strength, pressed Mo pellets were sintered in hydrogen atmosphere at temperature of 1600 °C. As a result of this process dimensions of Mo pellets decreased: diameter by 13 %, thickness by 12 %, weight by 1.5 %, volume by 34 % while density increased by 50 %. The changes of these parameters are associated with reduction of molybdenum oxide and removal of oxygen from intermetallic space. It was confirmed by photos of microscopic cross section of pellets before and after sintering. It was observed, that after sintering Mo pellets got a metallic form with very high hardness and mechanical strength.
4
Johansson, Joel. "Design Automation Systems for Production Preparation : Applied on the Rotary Draw Bending Process." Licentiate thesis, Jönköping University, Jönköping University, JTH, Mechanical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-10673.
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Intensive competition on the global market puts great pressure on manufacturing companies to develop and produce products that meet requirements from customers and investors. One key factor in meeting these requirements is the efficiency of the product development and the production preparation process. Design automation is a powerful tool to increase efficiency in these two processes.
The benefits of automating the production preparation process are shortened led-time, improved product performance, and ultimately decreased cost. Further, automation is beneficial as it increases the ability to adapt products to new product specifications with production preparations done in few or in a single step. During the automation process, knowledge about the production preparation process is collected and stored in central systems, thus allowing full control over the design of production equipments.
Three main topics are addressed in this thesis: the flexibility of design automation systems, knowledge bases containing conflicting rules, and the automation of the finite element analysis process. These three topics are discussed in connection with the production preparation process of rotary draw bending.
One conclusion drawn from the research is that it is possible to apply the concept of design automation to the production preparation process at different levels of automation depending on characteristics of the implemented knowledge. In order to make design automation systems as flexible as possible, the concept of object orientation should be adapted when building the knowledge base and when building the products geometrical representations. It is possible to automate the process of setting up, running, and interpreting finite element analyses to a great extent and making the automated finite element analysis process a part of the global design automation system.
5
Jaafar, Maisarah. "Trace elements in natural water : the impact on quality, food preparation and production." Thesis, University of Surrey, 2018. http://epubs.surrey.ac.uk/846339/.
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The levels of arsenic (total and species) and other trace elements in natural waters of Argentina were analysed using inductively coupled plasma mass spectrometer (ICP-MS). In addition, a method was developed for the determination of Mo in waters using graphite furnace atomic absorption spectrometry (GFAAS) with an added palladium chemical modifier. The analysis of Mo in certified reference materials and water samples using both methods confirmed no statistical difference using a paired t-test (tcal = 0.276; tcrit = 2.160, df: 14 at p<0.05). Arsenic total levels (AsT) in groundwaters followed the order; central-north La Pampa (48.82-1442.60 μg/l) > south-east La Pampa (17.66-319.39 μg/l) > southern Buenos Aires (39.6-189.4 μg/l) > Río Negro/Río Colorado (1.03-38.66 μg/l). The distribution of As species (using a field-based solid phase extraction method) were significantly different between the sampling regions. In most of the study areas the groundwater exceeded 10 μg/l AsT (World Health Organisation guideline for drinking water) and can be deemed to be not fit for human consumption since the calculated hazard quotient (HQ) >1. Apart from As, Mo and V also showed higher levels in groundwaters relating to the historical deposition of volcanic ash within the Chaco-Pampean plain of Argentina. The groundwaters from La Pampa ranged from 10 to 84 μg/l Mo. Surprisingly, one farm well south of Eduardo Castex (central-northern La Pampa) used for cattle drinking water had 1381.66 μg/l Mo. Significant positive correlations were found for As, Mo and V between groundwaters used on agricultural lands and the associated soils and pastures. The arsenic concentrations in groundwaters were found to be statistically correlated (r > 0.5) with the corresponding soils (total and exchangeable fraction) and plants (leaves and roots) at p < 0.01. Based on a sequential extraction method for soils, the uptake of arsenic from the soil exchangeable fraction by plants was found to be statistically correlated (rleaves = 0.5 and rroots = 0.7 at p < 0.01). Furthermore, the use of local groundwaters for food preparation (washing and cooking) alters the elemental composition of local foodstuffs (carrots, potatoes, onions and rice). The transfer of As, Mo, V, Mn, Fe, Cu, Zn from the water to foodstuffs was found to be dependent on the levels in the water, washing steps and the cooking process (time and method). A higher uptake of As, Mo and V by foodstuffs was observed when cooking with highly ̳contaminated‘ groundwaters, especially for rice. This may significantly increase the daily dietary intake of these elements as a function of food consumption. However, drinking water (2 l/day) is still considered the main contributor to the total daily intake of As, Mo and V for the local residents who rely upon groundwater as their source for drinking and cooking due to the lower Argentine food consumption rate (38 - 196 g/day). Similar trends were observed in West Bengal, India involving rice production and preparation (washing and cooking). Elevated levels were observed for As, Mn and Fe for all sample types (plants, soils, raw and prepared rice) in relation to the use of local groundwaters. Consumption of cooked rice (500 - 750 g/day) was observed to be the major contributor to the total daily dietary intake of As, Mn and Fe (depending on the rice variety) in the Indian study area when the local groundwater (94 μg/l AsT) was used in the preparation of rice, especially for local grown rice varieties.
6
Li, Tong. "Production of chitosanase by recombinant Streptomyces Lividans and enzymatic preparation of chitosan oligomers." Mémoire, Université de Sherbrooke, 1993. http://savoirs.usherbrooke.ca/handle/11143/4322.
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Elicitors are molecules which can trigger phytoalexin and pathogenesis-related proteins biosynthesis in plants. Chitosan as an elicitor has important roles in the interaction between pathogenic fungi and plants. Chitosan can inhibit fungal DNA transcription into mRNA, and it can also trigger the specific defensive genes which encode for at least 20 kinds of proteins related to resistant mechanism in plants. Elicitors are molecules which can trigger phytoalexin and pathogenesis-related proteins biosynthesis in plants. Chitosan as an elicitor has important roles in the interaction between pathogenic fungi and plants. Chitosan can inhibit fungal DNA transcription into mRNA, and it can also trigger the specific defensive genes which encode for at least 20 kinds of proteins related to resistant mechanism in plants. Chitosanase is an endoglycosidase that can hydrolyze chitosan into oligosaccharide fragments. Chitosan heptamer-more fractions showed maximal activity in both antifungal properties and induction of plant resistance. In this work, recombinant strains of Streptomyces lividans were used for production of chitosanase, then we used this enzyme to prepare the active chitosan oligomers and to test their antifungal properties and their ability to induce defensive responses in plants. In order to produce large amounts of chitosanase, the chitosanase gene from Streptomyces N174 was cloned in the high copy-number vector pFD666 and transformed into protoplasts of S. lividans TK24 and 10-164. These recombinant strains could produce chitosanase efficiently. The chitosanase activity could reach up to 95 units per millilitre of fermentation liquid on natural substrate (mycelium of Mucor rouxii. When DNA sequences were deleted in upstream or downstream of the chitosanase gene, chitosanase production became lower. Maybe, these sequences have some functions for the chitosanase gene expression and stability. In the chitosan medium, the chitosanase activity of the recombinant strains S. lividans TK24 decreased quickly after 3 days. We have shown that it related to the production of a specific proteolytic enzyme for chitosanase. On the contrary, the chitosanase activity could maintain high level after 3 days in M. rouxii mycelium as fermentation substrate. If S. lividans 10-164 was used as host for carrying the chitosanase gene, chitosanase activity reached high level after 2 days and the same level was maintained for a few days in D-glucosamine medium. The enzyme was recovered by polyacrylic acid precipitation. The enzyme prepared with this method has stable activity for long time. Using chitosanase hydrolysis, the heptamer-more fractions were prepared. These chitosan oligomers could inhibit fungal growth and could induce the production of pathogenesis-related proteins such as [beta]-1,3-glucanase, chitinase and chitosanase by plants.
7
Chan, Kent Lep. "A proposed character animation workflow for digital production arts with preparation for cloth dynamics." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1193078947/.
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Beaney, Alison M. "The development and implementation of appropriate standards for the preparation and production of medicines." Thesis, University of Sunderland, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.514221.
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Lim, Zi-Yian. "Preparation, modification, and characterisation of Yolk-shell structure based catalysts for synthetic gas production." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/41666/.
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Hydrogen is an emerging energy carrier for oil refining and fuel cell applications. The development of an efficient and stable catalyst to produce hydrogen gas is required for industrial applications. However critical issues in the catalyst that lead to the deactivation of reactions include active metal particle growth and carbon fouling. Industrial catalysts that are frequently overwhelmed by such issues are substituted or re-treated, which is not time and cost efficient. Therefore, developing durable catalysts that are resistant to sintering and carbon fouling remains an area of interest. A novel and anti-agglomeration Ni@yolk-ZrO2 catalyst is first reported in this thesis. A specific study of the ZrO2 hollow shell showed that the varied porosity of the hollow shell contributed to the catalyst’s ability to inhibit the agglomeration of active Ni particles. The steam reforming of methane was selected as the probe study for this catalyst in this research. Before a thorough analysis of the Ni@yolk-ZrO2 catalyst was performed, the systematic synthesis of Ni@SiO2 was studied. The analysis showed that the Ni particle size can be controlled by tuning the synthesis temperature. Water-to-surfactant ratio in the microemulsion was shown to influence the morphology of the Ni@SiO2 particle. The tetraethyl orthosilicate (TEOS) amount added with fractionated dispensing and the amount of NiCl2 were found to have affected the size and morphology of the Ni@SiO2. For the Ni@yolk-ZrO2 sample, the catalyst was characterised by Transmission Electron Microscopy (TEM) and X-Ray Diffraction. TEM was used for morphology analysis, while X-ray Diffraction was performed for phase analysis and crystallite size measurements. Nitrogen adsorption-desorption isotherm was done to measure specific surface area, total pore volume, and the t-plot micropore volume of the samples. Reducibility analysis of the Nickel species of the Ni@yolk-ZrO2 catalyst was carried out using Temperature Programmed Reduction. The anti-agglomeration property of the Ni@yolk-ZrO2 was established from the TEM and X-ray Photoelectron Spectroscopy analysis. Results showed that the active Ni particles were inside the yolk-shell structured framework, which deterred Ni particles from moving onto the surface of the catalyst. Ni particles were found to be stabilised by the abundant volume of pores in the ZrO2 hollow shell. This result indicates that the Ni particles were anchored by the pores and remained stable during the steam reforming of methane. The Ni@yolk-ZrO2 catalyst was tested by varying the volumes of feed (GHSV) and the steam-to-carbon ratio. This catalyst was also subjected to a recyclability test and proved to be better than conventional impregnated Ni/ZrO2 catalysts. The Temperature Programmed Hydrogenation analysis also proofed that the yolk-shell structure framework inhibited higher order of carbon deposits on the Ni@yolk-ZrO2 catalyst. Varying the porosity of the ZrO2 hollow shell was found to affect the performance of the steam reforming of methane. This varied porosity can be achieved by varying the amount of surfactant during the synthesis of Ni@SiO2@ZrO2. X-ray Photoelectron Spectroscopy analysis results showed that the porosity of the ZrO2 hollow shell contributed to the moderately strong hydrothermal stability of the catalyst for the steam reforming of methane. The hollow shell of the ZrO2 was influenced by the instability of the SiO2. TEM analysis of used BrNi-4.8 catalysts showed that the yolk-shell structure framework of the catalyst collapsed. This result suggests that the shell has weak integrity, and proves that the SiO2 was not able to maintain the yolk-shell framework. The results also suggest that the varied porosity of the ZrO2 hollow shell influences the catalysts’ efficiency even though they share the same yolk-shell structure framework. This is likely due to the differences in the pores of each catalyst configuration, which directly affects the Nickel species involved in the catalytic reaction. Finally, it was demonstrated that the Ni@yolk-ZrO2 catalyst exhibits excellent catalytic performance in comparison to conventional catalysts for the steam reforming of methane. Catalytic activity remained stable and achieved a methane conversion of more than 90 % for 150 hours under operating conditions of GHSV of 50400 mL gcat-1h-1 and S/C = 2.5 at 750 oC.
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Duke, Wendy S. "Experiencing Ionesco’s Nightmare World: The Preparation and Production of Man with Bags." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1289585453.
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Balkin, E. R., K. T. Strong, B. E. Smith, K. Gagnon, E. Dorman, R. Emery, P. Pauzauskie, et al. "Challenges associated with thick target preparation of WO3 for high current production of 186Re via deuteron irradiation." Helmholtz-Zentrum Dresden - Rossendorf, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-163876.
Full textAbstract:
Introduction
Rhenium-186 (t1/2 = 3.72 d) is very attractive for use as a theranostic agent in targeted radionuclide therapy (Eβ max = 1.072 MeV (> 76.6 %); Eγ = 137.2 keV)1. Previously published investigations of high specific activity 186Re production have utilized the 186W(p,n)186Re or 186W(d,2n)186Re reactions2-5. Our group is interested in the refinement and scale-up of the production of high specific activity 186Re by cyclotron irradiations of 186W with deuterons; including investigations of the most suitable target material. WO3 has been successfully used as a target material in proton irradiations by two other groups4,5. Further, the physical properties of WO3, such as the reported monoclinic with Pc space group, body centered cubic crystal structure6 and melting point of 1473 °C, made for an attractive target material as sintered and other more structurally robust pressed pellet target preparations could be explored. Thus, this study reports on the characterization and suitability of WO3 as a full-thickness target material for the deuteron production of 186Re.
Materials and Methods
Assessments of WO3 for target material suitability and structural integrity were made on thick targets (~1 g) prepared using both commercially available and converted WO3 by either uniaxially pressing (13.8 MPa) of powdered WO3 into an aluminum target support or by placing sintered WO3 pellets (1105 °C for 12 hours) into an aluminum target support.
In some experiments, WO3 pellets were prepared by dissolution of Wmetal with H2O2, then treatment with 1.5 M HCl. The recovered hydrated WO3 was calcinated at 800 °C for 4 hours, allowed to cool to ambient temperature, pulverized with a mortar and pestle, uniaxially pressed at 13.8 MPa into pellets with a 13 mm die, and subsequently sintered in a tube furnace under flowing Ar at 1105 °C for 3, 6, and 12 hours. Material characterization and product composition analyses were conducted with SEM, EDS, XRD, Raman spectroscopy, and visible photoluminescence spectroscopy.
Thick WO3 targets were irradiated for 10 min at 10 µA with nominal extracted deuteron energies of 17 MeV. Gamma-ray spectroscopy was per-formed to assess production yields and radionuclidic byproducts at least 24 hours post EOB.
Results
While the color of the commercially available WO3 is slightly different (dull, pale green) than the brighter more yellow color of the chemically processed WO3, X-ray diffraction spectrometry (XRD) indicated the two samples were virtually identical.
Attempts to determine how the duration of the sintering process (at 1105 °C) affects the chemical/physical nature of the pellet yielded surprising results. In contrast to the characteristic annealed appearance of sintered material, grains of the WO3 sample appeared more densely packed, but not sintered to one another as had been seen during higher temperature (1550 °C) reductions of WO3 irrespective of the time interval used.
Full-thickness pressed or sintered pellets of WO3 were found to disintegrate upon irradiation with the deuteron beam, allowing for the direct irradiation of the aluminum target body producing 24Na as a contaminant. Upon retrieval of the target support it was observed that the WO3 had vaporized, discoloring the surface of the well in the target support and coating the walls of ~61 cm (24 inches) of the terminal portion of the beamline, which then required decontamination. We believe that these observations are the result of outgassing oxygen species that subsequently reacted with the aluminum target support. While these findings are in sharp contrast with the successful production yields and isolations previously reported by both Shigeta et al. and Fassbender et al., we believe that these differences are attributable to differences in target design (previous studies utilized an en-closed target with cooling in front of and behind the target) necessitated by the configuration of our target station.
Conclusions.
The physical properties of powdered WO3, including its lower melting point and more suitable compressibility than powdered Wmetal, seemed to enhance the structural integrity of a WO3 pellet (whether pressed or sintered). However, when compared to our recent successes with the use of Wmetal based targets, the disappointing degradation of our WO3 targets when irradiated with the incident deuteron beam has led us to believe that Wmetal is the more viable target material for 186Re production in our facility.
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Лаврега, О. М. "Технологічне підготовлення виробництва деталей маслопреса." Thesis, Чернігів, 2021. http://ir.stu.cn.ua/123456789/25301.
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Лаврега, О. М. Технологічне підготовлення виробництва деталей маслопреса : випускна кваліфікаційна робота : 131 "Прикладна механіка" / О. М. Лаврега ; керівник роботи А. М. Єрошенко ; НУ "Чернігівська політехніка", кафедра технологій машинобудування та деревообробки. – Чернігів, 2021. – 239 с.Стратегічним напрямком збільшення виробництва продуктів харчування є розвиток прогресивної технології, що забезпечує високу якість готової продукції на основі впровадження нової техніки, що сприяє економії вихідної сировини, енергії, матеріалів. Створення й впровадження в промисловість сучасної, високоефективної техніки, прогресивної технології й матеріалів, що підвищують продуктивність, що поліпшує умови роботи, економію матеріальних і трудових ресурсів, а також спрямованих на охорону навколишнього середовища – головне завдання розвитку машинобудування. У зв'язку зі зростанням виробництва харчових продуктів процеси інтенсифікації й підвищення економічності обробки харчової сировини, одержання науково обґрунтованих вихідних даних для проектування й методики розрахунку встаткування стають ще актуальніше. Значна питома вага фізично й морально застарілого обладнання на харчових підприємствах, необхідність його корінного відновлення обумовлюють потребу у фахівцях, здатних розраховувати й проектувати нове прогресивне обладнання, засноване на використанні нових технологій, одержанні готового продукту високої якості й підвищенні технічного рівня виробництва. Найважливішими умовами створення прогресивного устаткування, що дозволяє ефективно вирішувати проблему комплексної переробки сільськогосподарської сировини й виробництва продуктів харчування, є: - всіляке зниження вартості нових конструкцій машин на одиницю продуктивності (потужності); - підвищення до оптимальних меж одиничної потужності машин при одночасному зменшенні їх габаритів; - зниження енергоспоживання, питомої металоємності; - забезпечення економічності в експлуатації, надійності й безпеці конструкцій машин. Реалізацію цих заходів можна здійснити за рахунок використання нових конструкційних рішень, автоматизованих методів розрахунку перспективних матеріалів підвищеної міцності, нових економічних профілів прокату й т.п. Застосування методів раціонального проектування технологічного встаткування, заснованих на використанні математичного моделювання на ЕОМ, дозволить в значній мірі автоматизувати процес розрахунку й конструювання машин і вибрати найбільш оптимальний варіант пропонованих рішень. Виходячи з усього вищевикладеного, тема кваліфікаційної роботи «Технологічна підготовка виробництва деталей маслопресу», досить актуальна.
The strategic direction of increasing food production is the development of advanced technology that provides high quality finished products based on the introduction of new technology, which saves raw materials, energy and materials. Creation and introduction in the industry of modern, highly effective equipment, advanced technology and materials that increase productivity, improve working conditions, save material and labor resources, as well as aimed at protecting the environment - the main task of mechanical engineering. In connection with the growth of food production, the processes of intensification and efficiency of processing of food raw materials, obtaining scientifically sound initial data for the design and calculation of equipment are becoming even more relevant. Significant share of physically and morally obsolete equipment in food companies, the need for its radical restoration determine the need for specialists who can calculate and design new advanced equipment based on the use of new technologies, obtaining high quality finished product and improving the technical level of production. The most important conditions for the creation of advanced equipment that can effectively solve the problem of integrated processing of agricultural raw materials and food production are: - a reduction in the cost of new machine designs per unit of productivity (capacity); - increase to the optimal limits of unit capacity of machines while reducing their size; - reduction of energy consumption, specific metal content; - maintenance of economy in operation, reliability and safety of designs of cars. The implementation of these measures can be carried out through the use of new design solutions, automated methods for calculating promising materials of high strength, new economic profiles of rolled products, etc. The use of methods of rational design of technological equipment, based on the use of mathematical modeling on a computer, will greatly automate the process of calculation and design of machines and choose the best option for the proposed solutions. Based on all of the above, the topic of the qualification work "Technological preparation for the production of parts of the oil press" is quite relevant.
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Bouhjar, Feriel. "Preparation et performance d'une cellule photocatalytique à base d'hématite pour la génération d'hydrogène." Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/106345.
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El hidrógeno es un portador de energía que ya ha demostrado su capacidad para reemplazar el
petróleo como combustible. Sin embargo, los medios de producción actualmente en uso
siguen siendo altamente emisores de gases de efecto invernadero. La foto-electrólisis del agua
es un proceso que, a partir de la energía solar, separa los compuestos elementales del agua
como el hidrógeno y el oxígeno utilizando un semiconductor con propiedades físicas
adecuadas. La hematita (¿-Fe2O3) es un material prometedor para esta aplicación debido a su
estabilidad química y su capacidad para absorber una porción significativa de la luz (con una
banda prohibida entre 2.0 - 2.2 eV). A pesar de estas propiedades ventajosas, existen
limitaciones intrínsecas al uso de óxido de hierro para la descomposición fotoelectroquímica
del agua. La primera restricción es la posición de su banda de conducción que es menor que el
potencial de reducción de agua. Esta limitación se puede superar mediante la adición en serie
de un segundo material, en tándem, que absorberá una parte complementaria del espectro
solar y llevar a los electrones a un nivel de energía más alto que el potencial para la liberación
de hidrógeno. El segundo obstáculo proviene del desacuerdo entre la corta longitud de
difusión de los portadores de carga y la profundidad de penetración larga de la luz. Por lo
tanto, es necesario controlar la morfología de los electrodos de hematita en una escala de
tamaño similar a la longitud de transporte del orificio.
En esta tesis, se introduce un nuevo concepto para mejorar el rendimiento fotoelectroquímico
de la hematita. Usando el método hidrotermal depositamos capas delgadas de hematita dopada
con Cr en sustratos de vidrio conductivo. También se ha preparado por medios
electroquímicos una heterounión del tipo p-CuSCN/n-Fe2O3 depositando secuencialmente una
capa de ¿-Fe2O3 y una película de CuSCNsobre sustratos de FTO (SnO2: F).Finalmente, se ha
preparado células solares de perovskitas y óxido de hierro. Para ello se depositó una capa
delgada, densa y uniformede óxido de hierro (¿-Fe2O3) como capa de transporte de electrones
(ETL) en lugar de dióxido de titanio (TiO2) que se utiliza convencionalmente en las células
fotovoltaicas perovskitastipoCH3NH3PbI3 (SGP). Este último dispositivo mostró un aumento
en la fotocorriente del 20% y un IPCE30 veces mayor que la hematita simple, lo que sugiere
una mejor conversión de las longitudes de onda por encima de 500 nm.
Palabras clave:
Fotoelectroquímica, división de agua, producción de hidrógeno, evolución de oxígeno,
semiconductores de óxido de metal, hematita, óxido de hierro, nanoestructurasHydrogen is an energy carrier that has already demonstrated its ability to replace oil as a fuel. However, the means of production currently used remain highly emitting greenhouse gases. Photo-electrolysis of water is a process that uses solar energy to separate the elemental compounds of water such as hydrogen and oxygen using a semiconductor with adequate physical properties. Hematite (¿-Fe2O3) is a promising material for this application because of its chemical stability and ability to absorb a significant portion of light (with a band-gap between 2.0 - 2.2 eV). Despite these advantageous properties, there are intrinsic limitations to the use of iron oxide for the photoelectrochemical cracking of water. The first constraint is the position of its conduction band, which is lower than the water reduction potential. This constraint can be overcome by the addition in series of a second material, in tandem, which will absorb a complementary part of the solar spectrum and bring the electrons to a higher energy level than the potential of hydrogen release. The second obstacle comes from the disagreement between the short diffusion length of the charge carriers and the long light penetration depth. It is therefore necessary to control the morphology of the hematite electrodes on a scale of similar size to the transport length of the hole. In this thesis a new concept is introduced to improve the photoelectrochemical performances. Using the hydrothermal method we deposited thin layers of Cr-doped hematite on conductive glass substrates. We also electrochemically prepared a p-CuSCN / n-Fe2O3 heterojunction by sequentially depositing ¿-Fe2O3 and CuSCN films on FTO (SnO2: F) substrates. Finally, we have used uniform and dense thin layers of iron oxide (¿-Fe2O3) as an electron transport layer (ETL) in place of titanium dioxide (TiO2) conventionally used in photovoltaic cells based on perovskites CH3NH3PbI3 (PSC). This latter concept showed a 20% increase of the photocurrent and an IPCE 30 times greater than the simple hematite, suggesting better conversion of high wavelengths (> 500 nm). Keywords: Photoelectrochemistry, Water Splitting, Hydrogen Production, Oxygen Evolution, MetalOxide Semiconductors, Hematite, Iron Oxide, Nanostructures, Surface.
L'hidrogen és un proveïdor d'energia que ja ha demostrat la seva capacitat per reemplaçar el petroli com a combustible, però els mitjans de producció actuals continuen essent fortament emissors dels gasos responsables d'efecte hivernacle. La fotoelectròlisi de l'aigua és un procés que, a partir de l'energia solar, separa els compostos elementals d'aigua com l'hidrogen i l'oxigen utilitzant un semiconductor amb propietats físiques adequades. La hematita (¿-Fe2O3) és un material prometedor per a aquesta aplicació a causa de la seva estabilitat química i capacitat d'absorbir una porció significativa de la llum (amb un gap entre 2,0 i 2,2 eV). Malgrat aquestes propietats avantatjoses, hi ha limitacions intrínseques per a l'ús d'òxid de ferro per a la descomposició fotoelectroquímica de l'aigua. La primera restricció és la posició de la seva banda de conducció que és inferior al potencial de reducció d'aigua. Aquesta limitació es pot superar mitjançant l'addició en sèrie d'un segon material, en tàndem, que absorbirà una part complementària de l'espectre solar i portar els electrons a un nivell d'energia més alt que el potencial per a l'alliberament d'hidrogen. El segon obstacle prové del desacord entre la curta durada de la difusió dels portadors de càrrega i la llarga profunditat de penetració de la llum. Per tant, és necessari controlar la morfologia dels elèctrodes d'hematita en una escala de mida similar a la longitud del forat del transport. En aquesta tesi, es presenta un nou concepte per millorar el rendiment fotoelectroquímic. Mitjançant el mètode hidrotermal es van dipositar capes primes de hematita Cr-doped sobre substrats de vidre conductor. També s'han preparat electroquímicamentheterounions de tipus p-CuSCN/n-Fe2O3 dipositant seqüencialment una capa de ¿-Fe2O3 i altra de CuSCN sobre substrats FTO (SnO2: F).Finalment, s'han produït cél·lules solars de perovskitesi óxid de ferro. Per això es va depositaruna capa prima,densai uniforme d'òxid de ferro (¿-Fe2O3) com a capa de transport d'electrons (ETL) en lloc de diòxid de titani (TiO2) que s'utilitza convencionalment en les cèl·lules fotovoltaiques de perovskita híbrida del tipus CH3NH3PbI3 (SGP). Aquest últim dispositiu va mostrar un augment del fotocorrent del 20% i una IPCE30 vegades superior a la hematita simple, la qual cosa suggereix una millor conversió a longitud d'ones per sobre de 500 nm. Paraules clau:Fotoelectroquímica, divisió d'aigua, producció d'hidrogen, evolució d'oxigen, semiconductors d'òxids metàl·lics, hematita, òxid de ferro, nanoestructures.
Bouhjar, F. (2018). Preparation et performance d'une cellule photocatalytique à base d'hématite pour la génération d'hydrogène [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/106345
TESIS
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Biyela, Busisiwe Nokukhanya E. "Evaluating the effect of different winemaking techniques on ethanol production." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/2493.
Full textAbstract:
Thesis (MscAgric (Viticulture and Oenology))--Stellenbosch University, 2008.Over the years, different techniques have been used to legally reduce the ethanol content of wines. Several physical processes are available for producing wines with less alcohol. Despite their efficacy, these treatments have a capital and operational cost influence. They can also affect the concentration of other wine components. On the other hand, vast amount of research has been conducted through genetic modification of wine yeast strains in order to reduce the ethanol yield of Saccharomyces cerevisiae by diverting sugar metabolism towards various byproducts. However, genetically modified yeasts are not currently accepted in most wine industries worldwide, including South Africa. Therefore, other approaches need to be envisaged. Commercial enzymes are commonly added during winemaking. Most enzymes essential for vinification naturally occur in grapes, but are inefficient under pH and sulphur levels associated with winemaking. Enzymes of fungal origin are resistant to such conditions. The most widely used commercial enzymes include pectinases, hemicellulases, glucanases and glycosidases. With the exception of glucanases, produced by Trichoderma harzianium, all the other enzymes are produced by Aspergillus niger. In this study, the possibility of using Gluzyme Mono® 10.000 BG (Gluzyme) (Novozymes, South Africa) to reduce the glucose content of synthetic grape must and grape must before fermentation in order to produce wine with a reduced alcohol content was investigated. Gluzyme is a glucose oxidase preparation from Aspergillus oryzae, currently being used in the baking industry. Glucose oxidase catalyses the oxidation of glucose to gluconic acid and hydrogen peroxide in the presence of molecular oxygen. Gluzyme was initially used in synthetic grape must where different enzyme concentrations and factors influencing its activity were investigated for its use in winemaking. The results showed that up to 0.5% v/v less alcohol were obtained using an enzyme concentration of 20 kU compared to the control. This reduction in alcohol was increased to 1 and 1.3% v/v alcohol at pH 3.5 and pH 5.5 respectively in aerated synthetic grape must using 30 kU enzyme. Secondly, Gluzyme trials were carried out using Pinotage grape must. Gluzyme treated wines after fermentation contained 0.68% v/v less alcohol than the control samples at 30 kU enzyme. Colour and volatile flavour compounds of treated wine did not differ significantly from the untreated samples. Lower free anthocyanin and total phenol concentrations in treated than control samples were observed, possibly due to the hydrogen peroxide oxidation which could have led to polymerisation. The present study has clearly demonstrated that Gluzyme may be used in winemaking to produce reduced-alcohol wine without affecting its colour and aroma compounds. The enzyme in its current form is however, not ideal for winemaking; other forms such as liquid or powder form should be considered if the enzyme is to be used under winemaking conditions. Future work should focus on evaluating the potential new form of the enzyme and studying the effects of Gluzyme in various grape must in semi-industrial scale. A tasting panel should also evaluate its impact on the organoleptic properties and the overall quality of the resulting wines.
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Balkin, E. R., K. Gagnon, E. Dorman, R. Emery, B. E. Smith, K. T. Strong, P. Pauzauskie, et al. "Thick target preparation and isolation of 186Re from high current production via the 186W(d,2n)186Re reaction." Helmholtz-Zentrum Dresden - Rossendorf, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-163779.
Full textAbstract:
Rhenium-186 has a half-life (t1/2 = 3.72 days) and emission of both gamma and beta particles that make it very attractive for use as a theranostic agent in targeted radionuclide therapy. 186Re can be readily prepared by the 185Re(n,γ)186Re reac-tion1. However, that reaction results in low specific activity, severely limiting the use of reactor produced 186Re in radiopharmaceuticals. It has previously been shown that high specific activity 186Re can be produced by cyclotron irradiations of 186W with protons and deuterons2,3. In this investigation we evaluated the 186W(d,2n)186Re reaction using thick target irradiations at higher incident deuteron energies and beam currents than previously reported. We elected not to use copper or aluminum foils in the preparation of our 186W targets due to their activation in the deuteron beam, so part of the investigation was an evaluation of an alternate method for preparing thick targets that withstand μA beam currents. Irradiation of 186W. Initial thick targets (~600-1100 mg) were prepared using 96.86% enriched 186W by hydraulic pressing (6.9 MPa) of tungsten metal powder into an aluminum target support. Those thick targets were irradiated for 10 minu-tes at 10 µA with nominal extracted deuteron energies of 15, 17, 20, 22, and 24 MeV.
Isolation of 186Re. Irradiated targets were dissolved with H2O2 and basified with (NH4)2CO3 prior to separation using column(s) of ~100–300 mg Analig Tc-02 resin. Columns were washed with (NH4)2CO3 and the rhenium was eluted with ~80˚C H2O. Gamma-ray spectroscopy was per-formed to assess production yields, extraction yields, and radionuclidic byproducts.
Recycling target material. When tested on a natural abundance W target, recovery of the oxidized WO4- target material from the resin was found to proceed rapidly with the addition of 4M HCl in the form of hydrated WO3. The excess water in the WO3 was then removed by calcination at 800 °C for 4 hours. This material was found to undergo reduction to metallic W at elevated temperatures (~1550 °C) in a tube furnace under an inert atmosphere (Ar). Quanti-fication of % reduction and composition analyses were accomplished with SEM, EDS, and XRD and were used to characterize and compare both the WO3 and reduced Wmetal products to a sample of commercially available material. Structural enhancement by surface annealing. In some experiments ~1 g WO3 pellets were prepared from Wmetal that had been chemically treated to simulate the target material recovery process described above. Following calcination, the WO3 was allowed to cool to ambient temperature, pulverized with a mortar and pestle and then uniaxially pressed at 13.8 MPa into 13 mm pellets. Conversion of the WO3 back to Wmetal in pellet form was accomplished in a tube furnace under flowing Ar at 1550 °C for 8 hours. Material characterization and product composition analyses were conducted with SEM, EDS, and XRD spectroscopy. Graphite-encased W targets. Irradiations were conducted at 20 μA with a nominal extracted deuteron energy of 17 MeV using thick targets (~750 mg) of natural abundance tungsten metal powder uniaxially pressed into an aluminum target support between layers of graphite pow-der (100 mg on top, 50 mg on the bottom). Targets were then dissolved as previously described and preliminary radiochemical isola-tion yields obtained by counting in a dose calibrator. Although irradiations of W targets were possible at 10 μA currents, difficulties were encountered in maintaining the structural integrity of the full-thickness pressed target pellets under higher beam currents. This led to further investigation of the target design for irradiations conducted at higher beam currents. Comprehensive target material characterization via analysis by SEM, EDS, XRD, and Raman Spectroscopy allowed for a complete redesign of the target maximizing the structural integrity of the pressed target pellet without impacting production or isolation. At the 10 A current, target mass loss following irradiation of an enriched 186W target was < 1 % and typical separation yields in excess of 70 % were observed. Saturated yields and percent of both 183Re (t½ = 70 days) and 184gRe (t½ = 35 days) relative to 186gRe (decay corrected to EOB) are reported in TABLE 1 below. The reason for the anomalously low yield at 24 MeV is unknown, but might be explained by poor beam alignment and/or rhenium volatility during irradiation. Under these irradiation conditions, recovery yields of the W target material from the recycling process were found to be in excess of 90% with no discernable differences noted when compared to commercially available Wmetal and WO3. Conceptually, increasing the structural integrity of pressed WO3 targets by high temperature heat treatment under an inert atmosphere is intriguing. However, the treated pellets lacked both density and structural stability resulting in disintegration upon manipulation , despite the initially encouraging energy dispersive X-ray spectroscopy (EDS) determination that 94.9% percent of the WO3 material in each pellet had been reduced to metallic W.
The use of powdered graphite as a target stabi-lizing agent provided successful irradiation of natural abundance W under conditions where non-stabilized targets failed (20 µA at 17 MeV for 10 minutes). Target mass loss following irradiation of a natW target was < 1 % and a separation yield in excess of 97 % was obtained. In conclusion, the theranostic radionuclide 186Re was produced in thick targets via the 186W(d,2n) reaction. It was found that pressed W metal could be used for beam currents of 10 μA or less. For deuteron irradiations at higher beam currents, a method involving pressing W metal between two layers of graphite provides increased target stability. Both target configurations allow high recovery of radioactivity from the W target material, and a solid phase extraction method allows good recovery of 186Re. An effective approach to the recycling of enriched W has been developed using elevated temperature under an inert atmosphere. Further studies are underway with 186W targets sandwiched by graphite to assess 186Re production yields, levels of contaminant radiorhenium, power deposition, and enriched 186W material requirements under escalated irradiation conditions (20 µA and 17 MeV for up to 2 hours).
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Lamamy, Julien-Alexandre 1978. "Enhancing the science return of Mars missions via sample preparation, robotic surface exploration and in orbit fuel production." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17776.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004.Includes bibliographical references (p. 225-230).
The future of Mars exploration is challenging from multiple points of view. To enhance their science return, future surface probes will most likely be equipped with complex Sample Preparation And Transfer (SPAT) facilities. Future rovers will need to be able to perform longer traverses and delicate sample acquisition operations. Mars return missions would benefit from a new propulsion system, with better fuel and travel time efficiencies than chemical and electric propulsions, respectively. A model was developed that optimizes SPAT facilities in terms of productivity and system mass. The SPAT model especially investigates two trade-offs: shared versus specific preparation, and warm versus cold redundancy for SPAT elements. A Mars Surface Exploration (MSE) framework was created to help designers perform preliminary studies on rover missions. MSE applies multidisciplinary design optimization techniques for the analysis of design trade-offs relevant to the rover design community. The Propellant Production In Mars Orbit (PPIMO) is presented as a promising solution for performing return travels to Mars. PPIMO uses the concept of regenerative aerobraking to produce fuel in-situ. The SPAT model shows that warm redundancy improves productivity by both reducing risk and removing sample throughput bottlenecks. A method is presented for determining the economy of scale the shared preparation architecture must exhibit for it to be competitive in comparison to the distributed architecture. MSE is used to budget the future development costs of rover autonomy, in addition to assessing: the benefits of oversized suspensions, the practicality of solar versus nuclear power for future missions, and the advantages of multi-rover missions. When compared
(cont.) to chemical and electric propulsions, PPIMO propulsion shows a better performance in terms of transportation ratio for payloads larger than 1000 kilograms.
by Julien-Alexandre Lamamy.
S.M.
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Schaer, Éric. "Conception d'un procédé pour la production de microparticules filtrables et redispersables." Vandoeuvre-les-Nancy, INPL, 1997. http://docnum.univ-lorraine.fr/public/INPL_T_1997_SCHAER_E.pdf.
Full textAbstract:
Ce travail concerne la précipitation de la silice, et plus précisément, la production d'un précipité de haute surface spécifique, filtrable et redispersable. Plusieurs processus sont alors à maitriser pour aboutir à ces caractéristiques : les vitesses de nucléation et de croissance modifient le nombre et la taille des nanoparticules constituant la silice précipitée. Elles auront donc une influence directe sur la surface spécifique. Les conditions d'agrégation et d'agglomération modifient quant à elles la taille et la cohésion finale du précipité. Elles auront alors une influence sur la filtrabilité et la redispersibilité du produit final. En vue de comprendre le déroulement de ces différentes étapes, nous les avons étudiées séparément. En mode semi-ferme, les mécanismes de nucléation et de croissance ont été analysés. La vitesse de nucléation a pu être estimée ; la vitesse de croissance a été mesurée, et une loi de croissance a été établie. En mode ferme, les phénomènes d'agrégation ont été étudiés, et les mécanismes d'agrégation ont pu être décrits par une cinétique en deux étapes. Les paramètres hydrodynamiques et physico-chimiques modifiant ce processus ont de plus été mis en évidence. Afin de maitriser les conditions de mélange des réactifs, un système original de mise en contact des réactifs par jets d'impact a été développé. Il permet de contrôler le déroulement des vitesses de nucléation et de croissance au cours de la précipitation, et constitue un critère de choix pour l'extrapolation du procédé à plus grande échelle. En mode semi-ferme, les jets d'impact ont permis l'optimisation de la surface spécifique et de la structure des agglomérats de silice, ainsi que l'obtention d'un produit aisément filtrable. La transposition du mode opératoire en continu nous a permis de nous affranchir du renforcement des agrégats observé en mode semi-ferme et nous a conduit à l'obtention d'un précipité de haute surface spécifique, filtrable et redispersable.
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Прокопенко, Ольга Володимирівна, Ольга Владимировна Прокопенко, Olha Volodymyrivna Prokopenko, J. Cebula, and M. Robert. "The trends in intensification of biogas production in France, Poland and in Germany." Thesis, Sumy State University, 2017. http://essuir.sumdu.edu.ua/handle/123456789/64685.
Full textAbstract:
Costs of substrates preparation for the methane fermentation are
crucial for the commercial success of using lignocellulosic material for the
production of biogas. Different procedural requirements exist for each substrate,
which can reduce the economic success. Thus, the choice of the technique
for pretreating substrate for different raw materials has basic meaning up in
individual countries.
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Willis-Fisher, Linda Salome Richard A. "A survey of the inclusion of aesthetics, art criticism, art history, and art production in art teacher preparation programs." Normal, Ill. Illinois State University, 1991. http://wwwlib.umi.com/cr/ilstu/fullcit?p9203045.
Full textAbstract:
Thesis (Ed. D.)--Illinois State University, 1991.Title from title page screen, viewed December 21, 2005. Dissertation Committee: Richard A. Salome (chair), Jack Hobbs, Noreen Michael, Marilyn P. Newby, Fred A. Taylor. Includes bibliographical references (leaves 112-115) and abstract. Also available in print.
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Růžička, Pavel. "Studie řízení výrobního procesu u vybraných produktů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231744.
Full textAbstract:
The thesis focuses on the process of production of castings in the company ŽĎAS, a.s. and its methods for implementing customer's requirements. The goal was to create a Work Flow diagram of technical preparation of production based on the company's internal directives. The next step was to compare it with the actual situation represented by a case job and to make a conclusion. The customer's requirements for the case production order included increased level of control and purchasing weld-on parts. The incorporation process for these requirements was not described by the original Work Flow and was the subject of its new revision. For its better practical application the Study contains business and organizational structures of ŽĎAS, a.s.
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Ankerfors, Mikael. "Microfibrillated cellulose : Energy-efficient preparation techniques and key properties." Licentiate thesis, KTH, Fiberteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102949.
Full textAbstract:
This work describes three alternative processes for producing microfibrillated cellulose (MFC) in which pulp fibres are first pre-treated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated with a combined enzymatic and mechanical pre-treatment. In the two other processes, cell wall delamination was facilitated by pre-treatments that introduced anionically charged groups into the fibre wall, by means of either a carboxymethylation reaction or irreversibly attaching carboxymethyl cellulose (CMC) onto the fibres. All three processes are industrially feasible and enable production with low energy consumption. Using these methods, MFC can be produced with an energy consumption of 500–2300 kWh/tonne, which corresponds to a 91–98% reduction in energy consumption from that presented in earlier studies. These materials have been characterized in various ways and it has been demonstrated that the produced MFCs are approximately 5–30 nm wide and up to several microns long.QC 20120928
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Bacela, Bandile Sakhekile. "An evaluation of changes in capital investment by automotive companies in preparation for the Automotive Production and Development Programme (APDP)." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1016075.
Full textAbstract:
To thrive, developing countries depend on high levels of protection being given to key industries such as manufacturing; specifically the automotive and textile industries. South Africa, as a developing country and especially under the emergence of globalisation, has followed suit in terms of developing policies and structures to protect certain critical industries. During an era (1980 to 1989) of high political instability, South Africa experienced isolation from the rest of the world, which resulted in declines in industrial revenues as well as the country’s automotive industry undergoing a stage of perilous stagnation. It was through a protection regime that the automotive industry realised growth, a regime which started slowly in 1989 and accelerated in 1995 with the introduction of the Motor Industry Development Programme (MIDP) (Black, 2001). Through this regime the South African government sought to integrate the South African automotive industry into the global market by improving the competitiveness of this industry (The DTI, 2010). This led to the automotive industry becoming one of the most successful export sectors in South African manufacturing and a large net consumer of foreign currency, totalling R20 billion and R10 billion in imports and exports respectively by 1998 (Damoense and Simon, 2004). Reviews of the government legislation called the MIDP were held in year 1999 and 2002 and in 2008, a successor to the MIDP was named, the Automotive Production Development Programme (APDP) and is set to commence in year 2013 until 2020. Unlike its predecessor, the APDP policy promises to bring greater and more inclusive benefits to the automotive industry as a whole, provided organisations have prepared well to receive it. This study investigated whether organisations have prepared for the upcoming 2013 - 2020 APDP, with specific reference to capital investment in equipment. It determined whether automotive organisations have spent and are going to spend resources in securing equipment and technology in preparation for the introduction of the APDP.
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Ankerfors, Mikael. "Microfibrillated cellulose: Energy-efficient preparation techniques and applications in paper." Doctoral thesis, KTH, Fiberteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159222.
Full textAbstract:
This work describes three alternative processes for producing microfibrillated cellulose (MFC; also referred to as cellulose nanofibrils, CNF) in which bleached pulp fibres are first pretreated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated by a combined enzymatic and mechanical pretreatment. In the two other processes, cell wall delamination was facilitated by pretreatments that introduced anionically charged groups into the fibre wall, by means of either a carboxymethylation reaction or irreversibly attaching carboxymethylcellulose (CMC) to the fibres. All three processes are industrially feasible and enable energy-efficient production of MFC. Using these processes, MFC can be produced with an energy consumption of 500–2300 kWh/tonne. These materials have been characterized in various ways and it has been demonstrated that the produced MFCs are approximately 5–30 nm wide and up to several microns long. The MFCs were also evaluated in a number of applications in paper. The carboxymethylated MFC was used to prepare strong free-standing barrier films and to coat wood-containing papers to improve the surface strength and reduce the linting propensity of the papers. MFC, produced with an enzymatic pretreatment, was also produced at pilot scale and was studied in a pilot-scale paper making trial as a strength agent added at the wet-end for highly filled papers.QC 20150126
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Keprt, Michal. "Technologie výroby součásti těleso klapky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230099.
Full textAbstract:
The goal of the work is to design the manufacturing process of the flap closure body weldment, which is to be produced with company Sevcik - Water Equipment Ltd. First, the flap closure is modelled with the 3D SolidWorks, according to technical documentation from the company. Furthermore, the welded construction has been analysed. In this work, the body weldment production technology and complete fabrication technological process of individual components and final assembly is described. The technical and economic evaluations are calculated and the cost of production has been quantified. The production of individual components, machining costs, and other relevant costs are included into the consideration. These calculations predict a compatible production.
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Kalina, Adam. "Technologie výroby zadané součásti." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231748.
Full textAbstract:
This document describes the design of new production technology specific part in an engineering company. The specific part is manufactured on a machining center by milling method. To create model was used SolidWorks software and to create CNC program was used SolidCAM program. There is production process created with new and old technologies. There is a comparison of both technologies in conclusion.
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Бурдейна, В. М., and А. Р. Тріщ. "Нормування полів розсіювання координованих розмірів глибоких отворів на етапі технологічної підготовки виробництва." Thesis, Сумський державний університет, 2016. http://essuir.sumdu.edu.ua/handle/123456789/47250.
Full textAbstract:
Оцінювання якості глибоких координованих отворів на етапі
проектування, тобто на етапі прийняття рішення про можливість
забезпечення їх повної взаємозамінності, враховуючи існуюче обладнання,
інструмент, матеріал та оснащення являється актуальною задачею. Рішення
таких питань потребує комплексу теоретичних і експериментальних
досліджень. Під координованими (взаємопов'язаними) отворами вважаємо
групи отворів, в яких задані міжосьові розміри або розміри від базової
поверхні до осей отвору. Під точністю розмірів координованих отворів
мається на увазі точність відстаней між отвором і базою та між двома або
декількома отворами (позиційне відхилення). Вимоги до точності отворів
задаються кресленнями.
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Johnson, Matthew C. "Identifying key factors in two-dimensional crystal production and sample preparation for structure-function studies of membrane proteins by cryo-EM." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52974.
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Electron crystallography of two-dimensional crystals is a structure-determination method well suited to the study of membrane protein structure-function. Two-dimensional crystals consist of ordered arrays of protein within reconstituted lipid bilayers, an arrangement that mimics the natural membrane environment. In this work we describe our recent progress in the use of this method with three different proteins, each providing a window into a separate paradigm in the electron crystallographic pipeline. Specific crystallization conditions for human leukotriene C₄ synthase (LTC₄S) have previously been determined, but our continued refinement of purification and crystallization has identified a number of additional parameters that greatly affect crystal size and quality, and we have developed a protocol to rapidly and reproducibly grow large, non-mosaic crystals of LTC₄S. The human gamma-glutamyl carboxylase (GGCX) has also been crystallized, but is sensitive to cryo-EM sample preparation conditions and we present here the successful reproduction of crystallization and refinement of cryo-EM sample preparation conditions. Lastly, we describe our crystallization screens with the Vibrio cholerae sodium-pumping NADH:ubiquinone reductase complex (Na⁺-NQR), and identify the factors critical to membrane reconstitution of the complex, a necessary first step towards crystallization. We also describe a semi-quantitative crystal screening protocol we have developed that provides quick and accurate method to assess two- dimensional crystallization trials, and discuss some general observations in optimization of membrane protein purification and two-dimensional crystallization for electron crystallography.
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Cromer, Cynthia Eckles. "Preparation and characterization of vanadium oxides on carbon fiber paper as electrodes for pseudocapacitors." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47623.
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Supercapacitors are important electrochemical energy storage devices for microelectronic and telecommunication systems, electric cars, and smart grids. However, the energy densities of existing supercapacitors are still inadequate for many applications. Vanadium oxides have been studied as viable supercapacitor alternatives, with varying results. Methods are often complicated or time-consuming, and electrode fabrication often includes carbon powder and binder. The objective of this work was to study the effect of processing conditions on specific capacitance of supercapacitors based on vanadium oxides coated on carbon fiber papers.
This study was conducted to form easily-fabricated compounds of vanadium oxides which could offer promise as pseudocapacitor material, and to nucleate these compounds directly onto inexpensive carbon fiber without binder. The incipient wetness impregnation technique was used to fabricate the electrodes. Electrochemical performance of the resulting electrodes was tested in a Swagelok-type electrochemical two-electrode cell, and the electrodes were characterized by XRD and SEM. Interesting nanofeatures were formed and the vanadium oxides exhibited pseudocapacitance at a respectable level.
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Максименко, О. М. "Технологічне підготовлення виробництва синусних пристроїв." Thesis, Чернігів, 2021. http://ir.stu.cn.ua/123456789/25303.
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Максименко, О. М. Технологічне підготовлення виробництва синусних пристроїв : випускна кваліфікаційна робота : 131 "Прикладна механіка" / О. М. Максименко ; керівник роботи С. П. Сапон ; НУ "Чернігівська політехніка", кафедра технологій машинобудування та деревообробки. – Чернігів, 2021. – 126 с.В випускній роботі розроблено технологічне підготовлення виробництва синусних пристроїв. В роботі здійснено розрахунки та проектування технологічного процесу механічної обробки плити та технологічний процес складання синусного пристрою. Розроблено планування дільниці механічної обробки плити з всіма необхідними розрахунками. Визначена площа дільниці, кількість обладнання та чисельність працюючих, енергетичні витрати необхідні для забезпечення діяльності дільниці. В конструкторському розділі спроектовано спеціальний пристрій для механічної обробки плити синусного пристрою. Запропоновані інженерні рішення з питань охорони праці та безпеки в надзвичайних ситуаціях. Наведено розрахунки техніко-економічної ефективності проектних розробок, умовно-змінних витрат на виробництво та обсягу початкових капіталовкладень.
In the final work, the technological preparation of the production of sinus devices was developed. In the work, calculations and design of the technological process of machining the plate and the technological process of assembling a sinus device were made. The layout of the slab machining area has been developed with all the necessary calculations. The area of the site, the number of equipment and the number of employees, the energy costs required to support the activities of the site have been determined. In the design section, a special device for machining the plate of the sinus device has been developed. Engineering solutions for labor protection and safety are proposed. Calculations of the technical and economic efficiency of design developments, conditionally variable costs of production and the volume of initial investment are presented.
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Höldrich, Markus [Verfasser], and Michael [Akademischer Betreuer] Lämmerhofer. "Nanoparticle-based Sample Preparation and High- Resolution Mass Spectrometry for Bioprocess and Quality Control in Biopharmaceutical Production / Markus Höldrich ; Betreuer: Michael Lämmerhofer." Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/1206173181/34.
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Cavusoglu, Gülperi [Verfasser], and J. D. [Akademischer Betreuer] Grunwaldt. "Preparation and Characterization of Catalysts for Efficient Hydrogen Production via the High Temperature Water Gas Shift Reaction / Gülperi Cavusoglu ; Betreuer: J.-D. Grunwaldt." Karlsruhe : KIT-Bibliothek, 2018. http://d-nb.info/1151938599/34.
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Yu, Wei. "Development of an elongational-flow microprocess for the production of size-controlled nanoemulsions : application to the preparation of composite and hybrid polymeric microparticles." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE027/document.
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L’objectif de ce travail fut de développer et d’étudier les performances d’un microprocédé basse pression à écoulement élongationnel pour la production de nanoémulsions polymérisables de tailles contrôlées et de distributions de taille étroites. Le diamètre des nanogouttelettes a pu être précisément ajusté dans la gamme 50-300 nm en modifiant simplement les paramètres de procédé : le débit réciproque au travers du micromélangeur, le nombre de cycles et la dimension caractéristique du microcanal. Les nanoémulsions produites furent, dans une seconde étape, polymérisées par voie thermique ou par irradiation UV afin de générer des suspensions colloïdales de nanoparticules de polymère de tailles également contrôlées (87-360 nm). Un monomère, un agent de réticulation ainsi qu’un amorceur thermique ou photochimique appropriés furent par la suite ajoutés au milieu continu de ces nanosuspensions. Les solutions résultantes servirent comme phases dispersées dans des générateurs microfluidiques de gouttelettes à capillaires. Les microgouttelettes de taille contrôlée ainsi produites furent polymérisées en ligne par irradiation UV pour donner lieu à des microsphères ou à des microparticules coeur-écorce composites de polymère toutes deux dopées avec des nanoparticules de polymère. Des microparticles composites et hydrides comportant des nanoparticules d’or dans le coeur et d’argent dans l’écorce furent également obtenues grâce à la réduction photochimique in situ des sels précurseurs lors de la photopolymérisation des microgouttelettes. Ce travail a démontré l’efficacité d’un nouveau dispositif microfluidique basse énergie pour la production de nanoémulsions et leur emploi pour la synthèse de matériaux polymères morphologiquement complexesThe aim of this work was to develop and to study the performances of a low pressure elongational-flow microprocess for the production of size-controlled polymerizable nanoemulsions with narrow size distributions. Nanodroplets diameter was easily tuned in the size range 50-300 nm by varying the process parameters, namely the reciprocating flow rate through the micromixer, the number of cycles and the characteristic dimension of the microchannel. Obtained nanoemulsions were in a second step thermally or UV-assisted polymerized to give colloidal suspensions of size-tunable polymer nanoparticles (87-360 nm). Then, a proper monomer, crosslinker and thermal- or photo-initiator were added to the continuous phase of these nanosupensions. The resulting mixtures were used as the dispersed phases of two different capillaries-based microfluidic droplet generators. The produced sizecontrolled microdroplets were finally UV polymerized online and plain as well as core-shell composite polymeric microparticles doped with lower scale polymer nanoparticles were obtained. Composite/hybrid polymeric core-shell microparticles were also synthesized for which gold nanoparticles in the core and silver nanoparticles in the shell were synthesized in situ from their salt precursors during microdroplets polymerization. This work has demonstrated the high efficiency of a novel low energy microfluidic emulsification device for the production of nanoemulsions which were used for the synthesis of morphologically complex polymeric materials
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SILVA, NESTOR C. da. "Estudo e otimizacao das condicoes de preparo do gel de molibdato de zirconio usado nos geradores de sup(99) Mo - sup(99m) Tc." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10966.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Полухина, С. Ю., Т. М. Осина, and В. Т. Прохоров. "Автоматизация технологической подготовки производства заготовок верха обуви." Thesis, Сумский государственный университет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/48082.
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Фактором конкурентоспособности продукции является сменяемость моделей. Она достигается путём совершенствования методов конструкторско-технологической подготовки производства. В условиях формирования рыночных отношений перед обувными предприятиями особую значимость приобретают вопросы технологичности изделия и сроки подготовки их к запуску при постоянном обновлении ассортиментного ряда выпускаемой продукции.
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Fisher, Daniel C. "PREPARATION AND APPLICATION OF CATALYSTS FOR THE STEREOSPECIFIC REDUCTION AND PHOTOOXYGENATION OF OLEFINS IN CONTINUOUS OPERATIONS: A NOVEL METHOD FOR THE PRODUCTION OF ARTEMISININ." VCU Scholars Compass, 2017. https://scholarscompass.vcu.edu/etd/5159.
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Over the last two centuries, the discovery and application of catalysts has had a substantial impact on how and what chemicals are produced.Given their broad significance, our group has focused on developing new catalyst systems that are recoverable and reusable, in an attempt to reduce concomitant costs.
Our efforts have centered on constructing a recyclable chiral heterogeneous catalyst capable of effecting asymmetric hydrogenations of olefins with high stereoselectivity. A class of phosphinoimidazoline ligands, developed by researchers at Boehringer-Ingelheim, known as BIPI ligands, have proven efficacious in the asymmetric reduction of alkenes. However, these chiral ligands are homogeneous and coordinated to precious metals, rendering them irrecoverable and expensive. To address these issues, our group has derivatized the BIPI ligand-metal complex and immobilized it to the surface of graphene oxide as well as polystyrene. Their efficacy and recyclability toward the asymmetric hydrogenation of a functionalized olefin have been evaluated.
Another facet of our work has included developing a cost effective synthetic process to artemisinin, the gold standard drug in the treatment of malaria.As a natural product, artemisinin’s worldwide supply remains highly unpredictable, contributing to great price volatility.Combining the benefits of catalysis and the advantages of continuous flow chemistry, our research has sought to develop an economical approach to convert a biosynthetic precursor, artemisinic acid, to artemisinin in three chemical transformations.
High-throughput experimentation allowed us to screen a prodigious number of catalysts and identify those effective in the asymmetric hydrogenation artemisinic acid to dihydroartemisinic acid, the first step in the transformation. This screening directed us to an inexpensive, heterogeneous ruthenium catalyst. The second step of the process includes the photooxygenation of dihydroartemisinic acid, which involves photochemically generated singlet oxygen. We have evaluated a commercially available heterogeneous photocatalyst packed in a transparent bed, surrounded by light emitting diodes in the continuous photooxygenation of dihydroartemisinic acid to dihydroartemisinic acid hydroperoxide. The third and final step, an acid induced hock cleavage, initiates an intricate cascading reaction that installs an endoperoxide bridge to deliver artemisinin. Our process afforded a 57% yield from dihydroartemisinic acid to artemisinin.
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Jarvis, Terence C. "The preparation of intermediates for the production of etoposide by the use of bio-transformations with plant cell cultures and plant cell culture extracts." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30929.
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This thesis investigates the use of plant cell cultures in combination with synthetic chemistry to provide a new and inexpensive route to etoposide, an anti-cancer drug (1). Two facets of plant cell culture technology were investigated The first of these involved the use of cell cultures as a reaction medium in which synthetic precursors were added to the cultures and the bio-transformation products analyzed. The second facet investigated was the use of cell cultures of Podophyllum peltatwn to directly produce podophyllotoxin (3) and 4'-demethylpodophyllotoxin (5) in the culture medium. These compounds could then be utilized as intermediates in the production of etoposide (1).
The synthetic studies involved the use of the readily available aromatic aldehydes, for example 3, 4-dihydroxybenzaldehyde (89), as starting materials. In an efficient route employing a tandem conjugate addition of 86 and 88 to the butenolide 87, the precursor 85 was prepared. By a similar route an efficient synthesis of the precursors 63 and 64 were performed.
Biotransformation of the precursors 62, 63 and 64 with the whole cell culture of Catharanthus roseus resulted in the production of 71 as the only identified product.
Compounds 62, 63 and 64 were treated with horseradish peroxidase (HRP) to compare plant cell enzymatic processes, with a commercially available peroxidase enzyme. The compound 63 was found to undergo bio-transformation to give the cyclized product 69 in 15-19% yield. Bio-transformation of the precursor 63 using a CFE (cell free extract) prepared from the cell culture of Catharanthus roseus.also produced the compound 69. Optimization of the conditions for this cyclization afforded 69 in 70% yield.
The bio-transformation of (62) with the CFE prepared from the cell culture of Catharanthus roseus afforded 79.
The precursor 85 was treated with the CFE prepared from the cell culture of Catharanthus roseus and found to cyclize to yield the product 115. The same cyclization was achieved by treatment of the precursor 85 with the CFE prepared from the cell culture of Podophyllum peltatum.
The precursor 116 was bio-transformed using both Podophyllum peltatum whole cells and the CFE of Catharanthus roseus to produce the compound 118. The compounds 69, 115 and 118 all have the necessary fused ring structure present in the podophyllotoxins, however they do not have the correct stereochemistry at position 1. Further work is in progress in our laboratory to address this problem.
The second part of this thesis is concerned with the hydroxylation of the butanolide 69 and deoxypodophyllotoxin (6) to produce an intermediate suitable for conversion into etoposide (1). Reactions were carried out with the CFE prepared from the cell culture of Catharanthus roseus using various co-factors. Procedures were employed to stabilize and characterize the enzyme preparations. Hydroxylation experiments were carried out with the cell culture of Tripterygium wilfordii using the precursors 6 and 69. Hydroxylation, using the CFE prepared from the cell cultures of Catharanthus roseus, of the precursors 133 and 134 obtained fron 6, afforded the hydroxylated product 139.
The final part of the thesis involves the isolation of the lignans podophyllotoxin (3), deoxypodophyllotoxin (6), podophyllotoxone (60) and 4'-demethylpodophyllotoxin (5), from the cell suspension culture of Podophyllum peltatum. This is the first time that these lignans have been isolated from the cell cultures of Podophyllum peltatum.Science, Faculty of
Chemistry, Department of
Graduate
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Pinto, Alberjan de Jesus Jean. "Eventos Kaizen aplicados no processo de linha de montagem SMT para redução de tempo de set-up: estudo de caso." Universidade Federal do Amazonas, 2011. http://tede.ufam.edu.br/handle/tede/3597.
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Previous issue date: 2011-07-15Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This work was aimed at applying the tools of the PRS System (Lean Production), whose primary tool was crafted VSM (Value Stream Mapping), a process known as SMT (Surface Mount Technology). Principles for lean production, eliminating waste and creating value stream in a real situation through kaizen events, were used to obtain results of this application, showing a lean transformation, with significant reductions in waste generated in the process. The study period was eight months into a private company located in PIM, where through the use of tools of this system and methodology of action research, it was possible to identify the critical process - setup - where focused improvement actions. With the change in the system setup, the standard work and creating a setup program using visual aid, favoring the continuous flow in this process. During the research, trainings were conducted in the factory with the operators, leaders, supervisors and engineers responsible, who participated actively in the improvement actions. Therefore, through value stream mapping, we propose to draw the current state of the stream, offering a future state, identifying and eliminating everything does not add value. To quantify the increase in productivity on the factory floor and total earnings of areas in the factory.
Este trabalho teve como objetivo a aplicação das ferramentas do Sistema de Produção Enxuta (SPE), cuja principal ferramenta trabalhada foi o Mapeamento da cadeia de valor (VSM), num processo denominado Tecnologia em Montagem de Superfície (SMT). Princípios que regem a produção enxuta, eliminação de desperdícios e a criação do fluxo de valor em uma situação real, através de eventos kaizen, foram utilizados para a obtenção de resultados dessa aplicação, evidenciando uma transformação enxuta, com expressivas reduções dos desperdícios gerados no processo. O período da pesquisa foi de oito meses em uma empresa privada situada no PIM, onde por meio da utilização de ferramentas desse sistema e a metodologia da pesquisa-ação, foi possível identificar o processo crítico setup para onde se concentraram as ações de melhorias. Com a mudança na sistemática de setup, no trabalho padronizado e criação de um setup programado, utilizando indicações visuais, favorecendo o fluxo contínuo nesta cadeia produtiva. No desenvolvimento da pesquisa, foram realizados treinamentos in loco com os operadores, líderes, supervisores e os engenheiros responsáveis, os quais participavam ativamente nas ações de melhoria. Portanto, através do mapeamento da cadeia de valor, propõem-se desenhar o estado atual da cadeia, propondo um estado futuro, identificando e eliminando aquilo que não agrega valor. Com isso, quantificar o aumento na produtividade no chão de fábrica e ganhos totais de áreas na fábrica.
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Paděra, Radek. "Zefektivnění výroby držáku jehelní tyče." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241146.
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This diploma thesis deals with the manufacturing of the needle bar holder for the company MINERVA BOSKOVICE, a.s. to propose the efficient production. The first part of diploma thesis is dedicated to the analysis of the technologies used for manufacturing the component. The second part of the thesis is focused on the analysis of the component and its current production. The third part suggests a design for a manufacturing process innovation containing the description of a new machine used for manufacturing, tool selection, technological process and mechanical calculations. The last part evaluates the current and a newly designed production and makes a comparison between the two ways.
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Švec, Michal. "Zefektivnění výroby součásti z šicího stroje." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417554.
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The diploma thesis deals with the proposal of more effective production process of the feeder holder component in the company MINERVA BOSKOVICE, a.s. The first part of diploma thesis dedicated to the technologies which are used in the production of components. The second part deals with the analysis of the component and its current production process. The third part contains a proposal for a new production process, which contains a description of the machines used for production, a new jig, selected tools, mechanical calculations and technological method. The last part evaluates the current and newly proposed variant of production with their comparison.
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Alyassin, Waleed. "The influence of heat production relative to drill wear during osteotomy preparation by different implant drill systems a comparison study between ceramic and conventional implant drill systems /." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/11068.
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Thesis (M.S.)--West Virginia University, 2010.Title from document title page. Document formatted into pages; contains vi, 41 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 37-41).
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Knight, James Jr. "COMMERCIALIZATION OF A METHOD FOR THE PREPARATION OF GLUCOSE SYRUP FROM WHOLE CASSAVA FOR USE AS A FIXED CARBON SOURCE FOR THE FERMENTATIVE PRODUCTION OF ALGAL OIL." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1291333498.
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Carvalho, Rodrigo Pinto de. "Proposta de modelagem da gestão da produção baseada no processo de preparação de urnas eletrônicas no TRE-AM." Universidade Federal do Amazonas, 2010. http://tede.ufam.edu.br/handle/tede/3494.
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Previous issue date: 2010-01-28The possibility of simulating in the computer a productive process makes it easier for managers to make decisions and also represents a substantial profit in allocations of resources for any company. Based on that, this project has as main goal develop a simulate model, based on operational research, that represents a generic production system. The preparation of electronic voting machines from The Regional Elections Court of Amazonas, TRE-AM, bureau responsible for planning and executing of elections in the state of Amazonas, Brazil, was used as emplacement of this model. Similarities between the election preparations and any productive process were observed by following the preparation of the electronic voting machines from 1996 to 2006 and specific tests were run in 2007. Information collected in these events based the necessity of building a simulation model contextualized for the construction of the information system. The simulation tool will have a very easy interface and it will provide validated results in real environments, allowing elaboration of production plans an statistic treatment to every need of the user. The outputs, as reports, graphics and database formats will offer abutment for decision making and will allow a wide and current systematic view of the corporations business strategy.
A possibilidade de simular computacionalmente um processo produtivo facilita a tomada de decisão por parte do gestor e representa um ganho substancial em alocação de recursos para qualquer empresa. Baseado neste princípio, este trabalho teve como objetivo propor um modelo de simulação que represente um sistema de produção genérico. Foi utilizado como base para construção desse modelo, o processo de preparação de urnas eletrônicas no TRE-AM, Tribunal Regional Eleitoral do Amazonas, órgão responsável pelo planejamento e execução das eleições no Estado. Similaridades entre a preparação eleitoral e um processo produtivo qualquer foram observadas por meio do acompanhamento das preparações das urnas entre os anos de 1996 e 2006 e de experimentos específicos realizados em 2007. Os dados coletados nestes eventos basearam a necessidade da construção de um modelo de simulação contextualizado para a construção do sistema de informações. Esse modelo servirá de base para futuro desenvolvimento de ferramenta computadorizada com interface facilitada e possibilidade de obter resultados validados em ambientes reais, permitindo elaboração de planos de produção e tratamento estatístico adequado às necessidades do usuário. As saídas do simulador, em formato de relatórios, gráficos e bases de dados, oferecerão respaldo para a tomada de decisão e permitirão uma visão sistemática ampla e atualizada da estratégia de negócio da corporação.
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Campos, Telmo Ribeiro de. "Proposta de um método de participação da produção utilizando o desenvolvimento enxuto de produto." Universidade Federal de São Carlos, 2008. https://repositorio.ufscar.br/handle/ufscar/3591.
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Previous issue date: 2008-12-16Lean manufacturing tools are well known and implemented to eliminate waste and improve materials flow throughout a production process. These lean principles are now studied and applied to product development process (PDP), aligned to the company s needs to develop and launch new products with lower cost and increased speed. Therefore, the objective of the present dissertation is to propose a production preparation procedure, that emphasizes: the significance of the manufacturing team s participation from project inception by sharing its experience, requirements and constraints; the vision of operational value stream delivery as a result of PDP and value creation related to customer and other stakeholders perception. To validate this proposal, a comparative application took place using a previous project from the company that was studied. Procedure comprehensiveness was assessed by questionnaire sent to professionals from other divisions, in addition to the division team. It was concluded that the proposed procedure is: feasible, updated and applicable; capable of contributing to waste, rework and project time reduction and helpful for sharing manufacturing lean concepts knowledge and expertise with other team members and product development stakeholders.
Atualmente, técnicas da manufatura enxuta são conhecidas e implementadas para eliminar desperdício e melhorar o fluxo de materiais ao longo de um processo de produção. Estes mesmos princípios enxutos são agora estudados e aplicados no processo de desenvolvimento de produto (PDP), alinhados à necessidade das empresas de desenvolverem e lançarem novos produtos com custo competitivo e no menor tempo possível. Portanto, o objetivo deste trabalho é propor um método para a produção, que enfatize: a importância da participação da manufatura desde o início do projeto para compartilhar sua experiência, necessidades e restrições; a visão de entrega de todo o fluxo operacional como resultado do PDP e a criação de valor segundo a percepção do cliente e demais interessados no projeto. Para validar a proposta, ela foi aplicada de forma comparativa em um projeto anteriormente realizado na empresa estudada; sua abrangência foi verificada mediante envio de questionário de avaliação do método a profissionais de outras divisões da empresa, além dos envolvidos no projeto avaliado. Como resultado, concluiu-se pela: viabilidade, atualidade e aplicabilidade do método; capacidade em contribuir para redução de desperdícios, de retrabalhos e do tempo de projeto; possibilidade de compartilhar o conhecimento e experiência da manufatura nos conceitos enxutos com os demais integrantes e interessados do projeto de desenvolvimento de produto.
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Габор, М. О. "Типові методи проектування металообробних інструментів із використанням інтернет - технологій." Thesis, Сумський державний університет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/39678.
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Основною метою технологічної підготовки виробництва (ТПВ) є досягнення під час виготовлення продукції оптимального співвідношення між витратами на виробництво та його результатами. Тенденція до збільшення частки малосерійного виробництва призводить до необхідності
підвищення якості та ефективності ТПВ та документування цього процесу. Технологічна підготовка виробництва, яке характеризується гнучкістю, повинна сама мати високий ступінь гнучкості. Одним з напрямків, що забезпечує підвищення ефективності технологічної підготовки виробництва є
автоматизація проектування засобів технологічного оснащення металорізальних верстатів і верстатних комплексів. Впровадження в проектування засобів технологічного оснащення комп'ютерних технологій суттєво зменшує безпосередні витрати на проектування та опосередковано –
витрати на виготовлення оснастки. Об’єктом дослідження є процес проектування засобів технологічного оснащення металорізальних верстатів і верстатних комплексів для дрібносерійного виробництва.
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Balhar, David. "Technologická příprava výroby stírací desky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378858.
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The main aim of this master's thesis is to propose a technological preparation of the wiping plate production. Elaboration is divided into four chapters. The first chapter describes forming tool (function and construction). In the second chapter is technologies overview, which are used for the wiping plate production. The most important is the third chapter, because it deals with the main output, and the actual proposal of technological preparation of the production. In the fourth chapter, production is reviewed economically.
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BARRIO, GRACIELA. "Desenvolvimento de tecnologias de preparo de geradores de sup(90)Sr/sup(90)Y na Diretoria de Radiofarmacia do IPEN/CNEN-SP." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9600.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Moudrá, Michaela. "Příprava a řízení stavební zakázky ve stavebním podniku." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240352.
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The aim of the thesis is to describe the preparation and management of construction contracts in terms of suppliers. In the thesis there are explained the basic terminology related to the preparation and management of construction contracts in terms of suppliers. The outcome of the thesis is the preparation of construction documentation from the supplier's perspective for the construction contract Agroturistika Kojatín.
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Багрій, Ярослав Вадимович, Ярослав Вадимович Багрий, Yaroslav Vadymovych Bahrii, Віталій Олександрович Іванов, Виталий Александрович Иванов, Vitalii Oleksandrovych Ivanov, and М. Едл. "Вдосконалення технологічної підготовки виробництва шляхом автоматизації проектування верстатних пристроїв." Thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/67404.
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Bassil, Siréna. "Procédé propre de production de chaleur et d'électricité à partir d'un biogaz produit à l'échelle domestique : exemples de matériaux catalytiques de reformage du méthane." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10055.
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Le reformage catalytique du méthane en hydrogène, vecteur d'énergie pour les piles à combustibles de type Solid Oxide Fuel Cell (SOFC), a été étudié sur des matériaux d'anode à base de métaux supportés (NiO/CeO2, NiO-Y2O3-ZrO2) et également sur des catalyseurs de structure définie (La0,8Sr0,2TiO3+δ). La première famille de catalyseurs a été synthétisée par deux méthodes de préparation : la technique d'imprégnation en milieu aqueux et en milieu organique sur des supports du commerce CeO2 et Y2O3-ZrO2 ou préparés au laboratoire, et par le procédé sol-gel. Le titanate de lanthane dopé au strontium a été préparé par la méthode de co-précipitation et également par la méthode sol-gel. La méthode de préparation a un effet important sur les propriétés physico-chimiques des catalyseurs synthétisés et par conséquent affecte à la fois leur activité catalytique en reformage du méthane et leur résistance à l'empoisonnement par le dépôt de carbone. Les catalyseurs à base de nickel supporté sur cérine ont été par la suite dopés avec l'oxyde de magnésium (formation d'une solution solide MgO-NiO) ainsi qu'avec l'oxyde de lanthane (La2O3-NiO) en vue de limiter la formation de carbone sur la surface catalytique et augmenter ainsi la durée de vie des catalyseurs lors du reformage du méthane. Les résultats obtenus montrent que l'effet de promotion de la phase active NiO par MgO ou La2O3 diminue à la fois le dépôt de carbone mais également les performances catalytiques. Les propriétés physico-chimiques et les performances catalytiques de NiO-Y2O3-ZrO2 préparé par le procédé sol-gel ont été comparées à celles de matériaux commerciaux (Aldrich & Jülich) de même composition. Les résultats expérimentaux montrent que les matériaux synthétisés par la méthode sol-gel sont plus actifs en vaporeformage du méthane que ceux du commerce (dans le domaine de fonctionnement d'une pile SOFC) alors qu'ils présentent une activité similaire à ces derniers en reformage à sec du méthane. La quantité de carbone graphitique formée, quoique supérieure à celle observée dans le cas des catalyseurs commerciaux, demeure faible (< 2%). Ce dépôt de carbone ne provoque qu'une légère diminution des performances catalytiques en reformage à sec du méthane. Ceci est probablement lié à la diminution des sites actifsThe catalytic reforming of methane into hydrogen, for direct operation of Solid Oxide Fuel Cells (SOFCs) on methane, was studied on anode materials such as NiO/CeO2, NiO-Y2O3-ZrO2 and La0.8Sr0.2TiO3+δ. The first group of catalysts was synthesized by two methods: the impregnation technique both in aqueous and organic media (commercial and laboratory made CeO2 and Y2O3-ZrO2), and also using sol-gel process. Lanthanumtitanium oxide host structure doped with strontium was prepared both by co-precipitation and sol-gel process. The method of preparation has an important effect on the physico-chemical properties of the synthesized catalysts and affects consequently both their catalytic performances in methane reforming and their resistance to poisoning by carbon deposition. In order to limit carbon formation on the catalytic surface and to increase the lifetime of catalysts during the catalytic reforming of methane, ceria supported nickel based-catalysts were doped with magnesium oxide (forming MgO-NiO solid solution) as well as with lanthanum oxide (La2O3-NiO). The obtained results show that the effect of promotion of NiO active phase by MgO and La2O3 decreases carbon deposition but also the catalytic performances. Physico-chemical properties and catalytic performances of NiO-Y2O3-ZrO2 (Ni-YSZ) prepared by the sol-gel process were compared with those of commercial (Aldrich and Jülich) materials having the same composition. The experimental results showed that materials synthesized by the sol gel method are more active in methane steam reforming than commercial catalysts while sol gel and commercial samples show similar performances in methane dry reforming. Amounts of graphitic carbon, although being higher for sol gel samples compared to commercial ones, remain low (< 2%). This carbon deposit provokes only a slight decrease of catalytic performances of sol gel prepared materials in methane dry reforming, probably by decreasing the number of active sites
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Nääs, Julia, and Michaela Martinez. "Svensk ull i textilproduktion. : En studie om vilka för- och nackdelar svenska textilföretag stött på i produktion med svensk ull." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-23502.
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Majoriteten av den ull som produceras av svenska får har under flera år slängts eller bränts upp. Samtidigt importerar svenska textilföretag tonvis med ull för miljoner kronor varje år. Detta problem uppmärksammades för några år sedan och ett antal svenska företag har sedandess börjat producera produkter av den svenska ullen. I denna kvalitativa studie har en undersökning gjorts för att sammanställa för- och nackdelar med att producera textilprodukter i svensk ull. Semistrukturerade intervjuer har genomförts med tio olika företag som idag jobbar med materialet. Resultatet av studien visar att det största problemet med ullproduktion inom Sverige är bristen på en strukturerad infrastruktur inom inköp och produktion. Fördelar med att producera textila produkter i svensk ull är att det är ett materialmed goda egenskaper för flera användningsområden. Det är ett hållbart materialval då ullen annars går till spillo. Närheten till materialet underlättar även kontrollen över att helavärdekedjan sköts på ett etiskt och hållbart sätt.The majority of the wool produced by Swedish sheep has been discarded or burned for several years. At the same time, Swedish textile companies import tons of wool for millions of swedish crowns each year. This problem was brought to attention a few years ago and a number of Swedish companies have since started to produce products from the Swedish wool. In this qualitative study, an investigation was conducted to compile the pros and cons of producing textile products in Swedish wool. Semi-structured interviews have been conducted with ten different companies that are currently working with the material. The results of the study show that the biggest problem with wool production in Sweden is the lack of an organized infrastructure in purchasing and production. The advantage of producing textile products in Swedish wool is that it is a material with good properties for several applications. It is a sustainable choice of material as the wool is otherwise wasted. The proximity to the material also facilitates the control of the entire value chain being managed in an ethical and sustainable way.