To see the other types of publications on this topic, follow the link: Rotary drum.
Dissertations / Theses on the topic 'Rotary drum'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 22 dissertations / theses for your research on the topic 'Rotary drum.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Jauhari, Ritika. "Gas-solid mass transfer in a rotary drum." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq21176.pdf.
Full text
2
Stine, Sarah G. "Enhancement of Municipal Wastewater Biosolids Drying through Interfacial Energy Modifying Amendments to Promote Uniform Agglomeration - Bench Scale Testing." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-theses/1269.
Full textAbstract:
Biosolids Drying is the process of producing a fertilizer product for beneficial reuse from solids produced during municipal wastewater treatment. The drying of biosolids involves the evaporation of water to stabilize the material and produce a product for beneficial use. Thermal energy needs to be transferred to the biosolids to evaporate the water and heat the solids. Energy can be provided by combustion of fuels, re-use of waste heat or solar radiation (WEF, 2014). The most common technology for biosolids drying in the United States utilizes rotary drum dryers. In these systems, fines and crushed oversized pellets produced during the drying system are mixed with dewatered biosolids upstream of the dryer to create a 55% - 65% dry biosolid in the form of pellets. Reducing the percentage of fines generated during the drying process can potentially reduce the amount of energy required for drying.
In earlier research completed by Zhang (2018) it was shown that energy modifying amendments, specifically cationic polyelectrolytes, can reduce the zeta potential of biosolids in solution and possibly promote aggregation of the fines. One of the tested amendments, polydiallyldimethylammonium chloride (PDADMAC), was also shown to increase the particle size of the biosolids in solution. In this work, a bench scale drying system was designed and developed to apply the polyelectrolyte amendments to biosolids during the mixing phase, and to gauge the impact on the pellet size distribution and the percentage of fines generated after drying. It was shown that PDADMAC, which is a high charge density cationic polyelectrolyte, had a measurable, though inconsistent, impact on pellet size when applied during the mixing phase. This work also highlights the varying characteristics of biosolids and the recycled biosolids produced during the drying process. Both PDADMAC, and polyallyamine, another cationic polyelectrolyte, when applied to biosolids during the mixing phase limited the increase in fines production as the mixing time was increased prior to drying.
3
Sabatka, Kyle Matthew. "Design and testing of an MR drum rotary device to achieve a variable effective compliance transmission." Connect to resource, 2006. http://hdl.handle.net/1811/5982.
Full textAbstract:
Thesis (Honors)--Ohio State University, 2006.Title from first page of PDF file. Document formattted into pages: contains xi, 86 p.; also includes graphics. Includes bibliographical references (p. 85-86). Available online via Ohio State University's Knowledge Bank.
4
Dick, Graeme. "Development and use of a discrete element model for simulating the bulk strand flow in a rotary drum blender." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/1517.
Full textAbstract:
In 2006 resin accounted for approximately 17% of the direct manufacturing costs for oriented strand board (OSB). Because of their increased dependency on pMDI-resins, this percentage is likely greater for oriented strand lumber (OSL) and laminated strand lumber (LSL). The cost of PF- and pMDI-resins is expected to face upward pressure as the cost of their primary constituents, natural gas and crude oil, continue to reach new highs. Therefore, there is strong economic incentive to optimize the use of resin in the production of these three products. This can be accomplished by addressing two key issues: reducing resin wastage and optimizing resin distribution on the strands. Both issues will be overcome by focusing on the blending process, where resin is applied to the strands.
This work focused on development and use of a discrete element model (DEM) for simulating strand flow in a rotary drum blender using the EDEM software package. EDEM required the input of three material and three interaction properties. Development of the model involved creating the simulated environment (i.e. physical dimensions) and assigning appropriate material and interaction properties given this environment and the assumptions that were made. This was accomplished in two steps, completing baseline bench-top experiments and a literature review to determine appropriate parameters and initial value ranges for these properties, and then fine-tuning these values based on a validation process.
Using the validated model, an exploratory study was conducted to determine the effect of four blender design and operating parameters (flight height, number of flights, blender rotational speed, and blender fill level) on bulk strand flow. The results were analyzed with regards to overall trends and by focusing on two perspectives, end users and blender manufacturers. It was found that there was a strong relationship between these key parameters and bulk strand flow. These results suggest that operating parameters of a blender, namely rotational speed and tilt angle, should be linked directly to the blender feed rate to ensure an optimal blending environment is maintained. In addition, manufacturers of blenders must take into consideration the range in final operating conditions when designing and positioning flights.
5
Gruber, Jan. "Sušení biomasy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231660.
Full textAbstract:
This thesis deals with the drying of biomass, especially drying of small wood mass. The various drying methods, such as belt drying, fluidized bed drying and drum drying are compared including their advantages and disadvantages. It is suggested basic technological scheme of drying line. The last part of the thesis deals with a calculation of drum dryer of specified performance and economic balance is made.
6
Karali, Mohamed Ahmed Mahmoud [Verfasser], Eckehard [Akademischer Betreuer] Specht, and Fabian [Akademischer Betreuer] Herz. "Analysis study of the axial transport and heat transfer of a flighted rotary drum operated at optimum loading / Mohamed Ahmed Mahmoud Karali. Betreuer: Eckehard Specht ; Fabian Herz." Magdeburg : Universitätsbibliothek, 2015. http://d-nb.info/1076590195/34.
Full text
7
Karali, Mohamed Ahmed Mahmoud Verfasser], Eckehard [Akademischer Betreuer] [Specht, and Fabian [Akademischer Betreuer] Herz. "Analysis study of the axial transport and heat transfer of a flighted rotary drum operated at optimum loading / Mohamed Ahmed Mahmoud Karali. Betreuer: Eckehard Specht ; Fabian Herz." Magdeburg : Universitätsbibliothek, 2015. http://nbn-resolving.de/urn:nbn:de:gbv:ma9:1-6740.
Full text
8
Salles, Poline. "Avaliação de um reator tipo tambor rotativo para hidrólise enzimática do bagaço da cana-de-açúcar." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18146/tde-25112013-103920/.
Full textAbstract:
A conversão biológica de biomassa celulósica em combustíveis e produtos químicos oferece elevados rendimentos de produtos para a o sucesso da economia e futuramente o potencial de custos muito baixos. A hidrólise enzimática, que converte a biomassa lignocelulósica a açúcares fermentáveis é uma etapa complexa do processo. Um requisito importante no custo-eficiente no processamento de biomassa lignocelulósica é empregar um reator que assegure, ou até mesmo promova uma elevada conversão de celulose para glicose com uma mínima dosagem de enzima. O objetivo da utilização do reator é também de processar um elevado teor de matéria seca e, consequentemente, elevados níveis de celulose que conduzem a um aumento na concentração do produto. No entanto, nos processos que empregam altas cargas de sólidos, além da viscosidade elevada do meio reacional, outros fatores afetam o processo, além da inibição do produto, sendo estes as limitações decorrentes da transferência de massa e a agitação e mistura do meio. Dentro deste contexto, o objetivo deste trabalho foi projetar um biorreator do tipo tambor rotativo para ser empregado no processo, em grande escala, de hidrólise enzimática do bagaço de cana-de-açúcar. Para alcançar este objetivo foram realizados experimentos, em escala de bancada, em um protótipo já existente no laboratório. Neste equipamento foi adicionado uma carga de sólidos de 10% (p/v) (bagaço de cana de açúcar, in natura e pré-tratado) e enzima celulase (Accellerase 1500® (Danisco)). Os resultados dos experimentos no reator mostraram um aumento na concentração de glicose (L⁻¹) convertida quando comparado com os realizados em frascos Erlenmeyer (controle). Isto ocorreu devido a melhor transferência de massa e de mistura no reator, sendo este mais eficiente, pois permite uma maior área de contacto da enzima com o substrato (bagaço).The biological conversion of cellulosic biomass to fuels and chemicals offers high yields of products for the success of the economy and future the potential for very low costs. Enzymatic hydrolysis that converts fermentable sugars in lignocellulosic biomass is a complex step in this process. An important requirement in cost-efficient in the processing of lignocellulosic biomass is to employ a reactor that will ensure, or even promote, maximal conversion of cellulose to glucose with a minimum dosage of enzyme. The purpose of using the reactor is also for to process of high dry matter contents and therefore higher levels of cellulose that will also drive up the product concentration. However, the processes that emply high solid loadings, in addition to the high viscosity of the reaction mixture and other factors than product inhibition, notably mixing and mass transfer limitations. Within this context, the aim of this work was to design a bioreactor rotary drum to be used in the process, with largescale enzymatic hydrolysis from sugarcane bagasse. To achieve this objective were performed in a bench scale, with prototype already existing in the laboratory. In this equipment was added a solids loading of 10% (w/v) (sugar cane bagasse, raw and pretreated) and cellulose enzyme (Accellerase 1500® (Danisco)). The results of the reactor experiments showed an increase in glucose concentration (L⁻¹) converted when compared with those realized in Erlenmeyer flasks (control). This occurred because the mass transfer and mixing in the reactor is more efficient because it allows greater contact area of the enzyme with the substrate (sugarcane bagasse).
9
Mesnier, Aline. "Étude expérimentale et simulation de la ségrégation mécanique et thermique de billes millimétriques dans un séchoir de type tambour tournant." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1046/document.
Full textAbstract:
La problématique de l’homogénéité de traitement mécanique et thermique d’un lit particulaire bi-disperse en tailles ou en densités dans un tambour tournant horizontal a été abordée. Dans la première partie, le mélange des billes sphériques millimétriques dans un tambour de type ‘tranche’ a été observé expérimentalement à l’aide des maquettes originales et simulé numériquement à l’aide d’un code commercial de type DEM. En ajustant le coefficient de frottement entre les billes, un accord satisfaisant a été obtenu entre les résultats des simulations et des expériences. Le lit a été globalement caractérisé par l’indice de ségrégation radial, la répartition des billes dans la couche frontale et l’angle de talus dynamique. Des phénomènes importants de ségrégation radiale et axiale ont été mis en évidence. Une réduction très significative de l’indice de ségrégation radiale a été obtenue dans le cas des ailettes multiples et longues par rapport au cas avec peu d’ailettes courtes ou pas d’ailettes. Dans la deuxième partie, le chauffage des billes par contact avec la paroi périphérique du tambour a été simulé par la méthode DEM. Des lits mono-disperse, bi-disperse (comme dans la partie 1), et à dispersion gaussienne ont été considérés. Les indices de ségrégation mécanique et thermique ont été comparés pour les différents types de lits et différentes configurations d’ailettes. L’intensité de la ségrégation thermique a été renforcée, dans l’ensemble, par la ségrégation mécanique et a été la plus forte pour le lit bi-disperses en densités. L’augmentation de la hauteur et du nombre des ailettes a considérablement amélioré l’homogénéité thermique du lit et la vitesse globale de chauffageProduct homogeneity issue during mechanical and thermal processing of a bi-dispersed bed with two particles’ sizes or two particles’ densities in a horizontal rotary drum was considered. In the first part, the mixing of milli-metric size spherical beads in a two-dimensional drum was simulated by means of a commercial discrete element software and optically observed in a specially designed laboratory scale device. The spatial distribution of the particles in the front bed section, the radial mechanical segregation index and the dynamic slope angle were analyzed. After adjusting the friction coefficient, the simulation results were close to the experimental ones. Important phenomena of radial and axial segregation have been highlighted. The radial segregation index was found to be significantly decreased by applying an important number of long baffles, while using few short baffles had practically no influence on segregation intensity. In the second part, the heating of the bed of spherical beads in a 2D drum with hot peripheral wall was simulated by means of the discrete element software. Mono-dispersed, gaussian-dispersed and bi-dispersed beds (same as in part 1) were considered. The mechanical segregation and the thermal segregation indexes were calculated for the different types of bed and for different baffles configurations. The thermal segregation was found to be generally enhanced by the mechanical segregation and reached its highest values for the bi-density bed. Increasing the number and the length of the baffles considerably improved the overall heating rate and the thermal homogeneity of the considered beds
10
Pečenka, Tomáš. "Rotační manipulátor pro ruční svařování bubnů zakladače EXYZ." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318636.
Full textAbstract:
The main aim of this diploma thesis is to design rotary manipulator for manual welding of hoist drums for EXYZ storage machine. The rotary manipulator is designed for improving of the quality of welds, which have been made in the static bearing welding process of hoist drum. The first part is concerned on the critical research of welding manipulators, which could be founded on the market. In the next part, there are sketched possible construction designs of welding manipulator based on the market offer. The main part of the diploma thesis is own construction design, which is made on the base of suggested concept of construction design.
11
Black, Jennifer May. "Particle motion and heat transfer in rotary drums." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/11987.
Full text
12
Altiparmak, Duran. "Factors affecting the swirl at entry to the balance drum in a centrifugal pump." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1466.
Full text
13
Rotan, Olga [Verfasser], and Matthias [Akademischer Betreuer] Epple. "Calcium phosphate nanoparticles for medical application : drug and vaccine delivery / Olga Rotan. Betreuer: Matthias Epple." Duisburg, 2016. http://d-nb.info/1099910277/34.
Full text
14
Arantes, Fabricio Soares. "Comparação das duas principais rotas de obtenção do megazol." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/9/9135/tde-07122007-101051/.
Full textAbstract:
Este trabalho tem como meta o estudo comparativo de duas rotas de síntese do megazol, tomando como base estudos feitos na Faculdade de Ciências Farmacêuticas da USP. Nestes foram observados que a obtenção do megazol pode ser feita por diferentes caminhos sintéticos, modificando processos e reagentes envolvidos na química de heterocíclicos, em particular os imidazóis. Foram avaliadas condições experimentais, rendimentos parciais e globais bem como as características de reagentes envolvidos nos processos indicados.The scope of the present work is the analogy study over the two main routes on megazol synthesis, based on studies previously accomplished at the College of Pharmaceutical Sciences of USP. In the results of the above referred studies, it was observed that the obtaining of the megazol can be achieved by different synthetic ways, by modifying processes and reagents related to the chemical properties of heterocyclic compounds, particularly with the imidazoles. Experimental conditions, both partial and final yields as well as the characteristics of the reagents evolved in the indicated processes were evaluated.
15
Martins, Pedro Raphaël. "Fibrillation atriale : des mécanismes physiopathologiques à la prise en charge thérapeutique." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1B010/document.
Full textAbstract:
La fibrillation atriale (FA) est l’arythmie soutenue la plus fréquente ; elle entraine une majoration significative de la morbidité et de la mortalité. Les mécanismes qui en sont responsables sont encore incomplètement connus, et sa prise en charge n’est pas optimale. Afin de mieux comprendre la physiopathologie de la FA, nous avons mené différents travaux sur des coeurs de moutons isolés et perfusés par un système de Langendorff mais également en créant un modèle chronique de FA persistante de longue durée. Dans un modèle ovin de FA persistante, nous avons ainsi démontré que la fréquence dominante (DF) de la FA augmentait progressivement pendant les premières semaines de l’arythmie, alors que les épisodes étaient paroxystiques, phénomène en rapport avec le raccourcissement de la durée du potentiel d’action secondaire au remodelage électrophysiologique. La DF se stabilisait dès lors que la FA devenait persistante, une fois le remodelage électrophysiologique maximal. L’accélération de la DF (dDF/dt) était significativement corrélée au temps nécessaire à la transition vers la FA persistante. Le remodelage structurel n’apparaissait que secondairement, une fois l’arythmie devenue persistante. Sur le plan thérapeutique, nous avons étudié les mécanismes anti-arythmiques de la chloroquine (bloqueur d’IK1) et de la ranolazine (bloqueur d’INa), molécules entrainant un ralentissement de la fréquence de rotation des rotors, une diminution de la DF et un retour en rythme sinusal. Ces travaux nous ont permis de mieux appréhender le rôle des ces courants ioniques dans le maintien de la FA. Enfin, nous avons démontré l’efficacité de l’ablation de la FA en utilisant le cryoballon (CB) de deuxième génération, efficacité grevée d’un taux de parésie du nerf phrénique élevé, dont nous avons pu prédire la survenue à l’aide d’un prédicteur simple, la distance entre le bord du CB et la cathéter permettant de stimuler le nerf phrénique pendant l’application. Une meilleure compréhension des mécanismes à l’origine de l’initiation et du maintien de cette arythmie, ainsi qu’une meilleure prise en charge thérapeutique permettraient d’améliorer la qualité de vie des patients et d’en diminuer le taux de complicationsAtrial fibrillation (AF) is the most common sustained arrhythmia, significantly increasing patients’ morbidity and mortality. The mechanisms explaining the initiation and maintenance of the arrhythmia are incompletely understood, and the current treatment strategy is suboptimal. To better understand the pathophysiology of AF, we conducted various projects using Langendorff-perfused sheep hearts and a chronic model of long-standing persistent AF. In the model of persistent AF, we demonstrated that dominant frequency (DF) progressively increases during the first weeks of the arrhythmia, during its paroxysmal stage, due to the electrophysiological remodeling resulting in atrial action potential shortening. DF stabilizes once the electrophysiological remodeling is maximal, and the arrhythmia becomes persitent. The rate of DF increase (dDF/dt) was strongly correlated with the time to persistent AF. Structural remodeling appears secondarily, once transition has occured. We also studied the anti-arrhythmic mechanisms of chloroquine (IK1 blocker) and ranolazine (INa blocker), which slow the frequency of rotation of rotors, decrease the DF and favor reversal to sinus rhythm. These projects helped us to better understand the importance of these currents in AF dynamics. Lastly, we demonstrated the increased efficacy of AF ablation when using the second generation cryoballoon (CB), which regrettably increases the occurrence of phrenic nerve palsy. A simple, reliable predictor of this complication was found, the distance between the lateral edge of the CB and the phrenic nerve stimulating catheter. A better understanding of the mechanisms underlying the initiation and maintenance of AF, in conjunction with better therapeutic strategies will help to improve patients’ quality of life and decrease the complications of the arrhythmia
16
Hansen, Tarrant William. "Evaluation of molecular methods used for the rapid detection of multi-drug resistant Mycobacterium tuberculosis." Queensland University of Technology, 2008. http://eprints.qut.edu.au/20723/.
Full textAbstract:
Tuberculosis remains a major public health issue globally, with an estimated 9.2 million new cases in 2006. A new threat to TB control is the emergence of drug resistant strains. These strains are harder to cure as standard anti-tuberculosis first line treatments are ineffective. Multi Drug Resistant Tuberculosis (MDR-TB) is defined as Mycobacterium tuberculosis that has developed resistance to at least rifampicin and isoniazid, and these strains now account for greater than 5% of worldwide cases. Mutations within the Rifampicin Resistance Determining Region (RRDR) of the rpoB gene are present in greater than 95% of strains that show rifampicin resistance by conventional drug susceptibility testing. As rifampicin mono resistance is extremely rare, and rifampicin resistance is usually associated with isoniaizd resistance, the RRDR region of the rpoB gene is a very useful surrogate marker for MDR-TB. Many molecular assays have been attempted based on this theory and have had varied levels of success. The three methods evaluated in this study are DNA sequencing of the rpoB, katG and inhA genes, the Genotype MTBDRplus line probe assay (Hain Lifesciences) and a novel method incorporating Real-Time PCR with High Resolution Melt analysis targeted at the RRDR using the Rotorgene 6000 (Corbett Lifesciences). The sensitivity for the detection of rifampicin resistance was far better using DNA sequencing or the commercially available line probe assay than detection by the Real-Time PCR method developed in this study.
17
"Heat Transfer in a Rotary Drum Using Infrared Camera Temperature Measurement." Master's thesis, 2019. http://hdl.handle.net/2286/R.I.53613.
Full textAbstract:
abstract: Rotary drums are commonly used for their high heat and mass transfer rates in the manufacture of cement, pharmaceuticals, food, and other particulate products. These processes are difficult to model because the particulate behavior is governed by the process conditions such as particle size, particle size distribution, shape, composition, and operating parameters, such as fill level and rotation rate. More research on heat transfer in rotary drums will increase operating efficiency, leading to significant energy savings on a global scale.
This research utilizes infrared imaging to investigate the effects of fill level and rotation rate on the particle bed hydrodynamics and the average wall-particle heat transfer coefficient. 3 mm silica beads and a stainless steel rotary drum with a diameter of 6 in and a length of 3 in were used at fill levels of 10 %, 17.5 %, and 25 %, and rotation rates of 2 rpm, 6 rpm, and 10 rpm. Two full factorial designs of experiments were completed to understand the effects of these factors in the presence of conduction only (Case 1) and conduction with forced convection (Case 2). Particle-particle friction caused the particle bed to stagnate at elevated temperatures in Case 1, while the inlet air velocity in Case 2 dominated the particle friction effects to maintain the flow profile. The maximum heat transfer coefficient was achieved at a high rotation rate and low fill level in Case 1, and at a high rotation rate and high fill level in Case 2. Heat losses from the system were dominated by natural convection between the hot air in the drum and the external surroundings.Dissertation/Thesis
Masters Thesis Chemical Engineering 2019
18
HUI-HUNG, CHENG, and 鄭惠宏. "Development and Study of a Drum Rotary Dryer for Pangola Grass." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/96872972269837191033.
Full textAbstract:
碩士國立屏東科技大學
機械工程系
89
The purpose of this research was to investigate the drum rotary dryer for pangola grass drying. The forage variety used was pangola grass A254. The objectives of this study were to elucidate the characteristics of this specific drum rotary dryer. The drying machine is consisted of burner, dryer, blower, cyclone, convey or et al. Experiments were proceeded according to the characteristics of the machine. The operating parameters were feed rate, particle size and excess air. Besides the drying efficiency and collection efficiency of pangola grass, analysis were carried out on the composition of crude protein, crude fat, crude fiber and trace elements of Phosphorus, Potassium, Calcium, as well as ash content of panagola grass after drying. The primary objective was set at improving the operating efficiency of this drying machine. The results showed that drying efficiency could be enhanced, if the panagola grass was pre-cut. Moreover it can increase the drying efficiency and avoid the forage clogging in the drying machine. The optimum conditions found that air velocity is about 7.1~8.3 m/s, panagola grass size 6 cm, and feed rate 10 kg/min. There was no significant difference on the approximate compositions when compared with used solar drying. It shows the potential of applying machine drying in replacing solar drying.
19
Chang, Wei Gy, and 張維吉. "On the Design for the Tape Loading Mechanism of Rotary Drum Type Deck." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/80695995378025194333.
Full text
20
"Statistical Analysis of 3D-DEM for Steady State Conduction Heat Transfer in a Rotary Drum." Master's thesis, 2020. http://hdl.handle.net/2286/R.I.62678.
Full textAbstract:
abstract: The current research is based on the principles of three-dimensional discrete element method (3D – DEM) through simulations, by using heat transfer models in EDEM, to investigate the effects of fill level, rotation rate and particle size on the steady-state conduction heat transfer in rotary drums. The high heat and mass transfer rates obtained through rotary drums make them very useful for powder mixing and heating processes in metallurgical, cement, mining, pharmaceutical, detergent and other particulate processing applications. However, these complex processes are difficult to model and operate since the particles can have a wide range of properties, and there is currently no way to predict the optimal operating conditions for a given material.
Steady-state heat transfer by conduction forms the basis for understanding other steady-state and unsteady-state heat transfer in a rotary drum – conduction, convection and radiation. Statistical analysis is carried out to determine the effects of these process parameters and find optimal operating conditions, which will thereby improve the heat transfer efficiency in rotary drums. A stainless-steel drum with a diameter of 6 inches and a length of 3 inches was modeled in EDEM with silica beads of sizes 2 mm, 3 mm and 4 mm at fill levels of 10%, 17.5% and 25%, and at rotation rates of 2 rpm, 5 rpm and 10 rpm. It was found that the heating uniformity increased with decreasing particle size, decreasing fill level and increasing rotation rate. This research is the first step towards studying the other heat transfer modes and various other process parameters. Better understanding of the various heat transfer modes, when used in combination for heating the particles, will be beneficial in improving the operating efficiency, reducing material costs and leading to significant energy conservation on a global scale.Dissertation/Thesis
Masters Thesis Chemical Engineering 2020
21
"Numerical Modeling and Experimental Studies on the Hydrodynamics and Heat Transfer of Silica Glass Particles." Doctoral diss., 2020. http://hdl.handle.net/2286/R.I.57399.
Full textAbstract:
abstract: Granular material can be found in many industries and undergo process steps like drying, transportation, coating, chemical, and physical conversions. Understanding and optimizing such processes can save energy as well as material costs, leading to improved products. Silica beads are one such granular material encountered in many industries as a catalyst support material. The present research aims to obtain a fundamental understanding of the hydrodynamics and heat transfer mechanisms in silica beads. Studies are carried out using a hopper discharge bin and a rotary drum, which are some of the most common process equipment found in various industries. Two types of micro-glass beads with distinct size distributions are used to fill the hopper in two possible packing arrangements with varying mass ratios. For the well-mixed configuration, the fine particles clustered at the hopper bottom towards the end of the discharge. For the layered configuration, the coarse particles packed at the hopper bottom discharge first, opening a channel for the fine particles on the top. Also, parameters such as wall roughness (WR) and particle roughness (PR) are studied by etching the particles. The discharge rate is found to increase with WR, and found to be proportional to (Root mean square of PR)^(-0.58). Furthermore, the drum is used to study the conduction and convection heat transfer behavior of the particle bed with varying process conditions. A new non-invasive temperature measurement technique is developed using infrared thermography, which replaced the traditional thermocouples, to record the temperatures of the particles and the drum wall. This setup is used to understand the flow regimes of the particle bed inside the drum and the heat transfer mechanisms with varying process conditions. The conduction heat transfer rate is found to increase with decreasing particle size, decreasing fill level, and increasing rotation speed. The convection heat transfer rate increased with increasing fill level and decreasing particle size, and rotation speed had no significant effect. Due to the complexities in these systems, it is not always possible to conduct experiments, therefore, heat transfer models in Discrete Element Method codes (MFIX-DEM: open-source code, and EDEM: commercial code) are adopted, validated, and the effects of model parameters are studied using these codes.Dissertation/Thesis
Doctoral Dissertation Chemical Engineering 2020
22
Sousa, Sílvia Maria Ferreira. "Tráfico internacional de estupefacientes Portugal e Espanha como portas de entrada na Europa: as «entregas controladas» como estratégia conjunta na investigação criminal." Master's thesis, 2019. http://hdl.handle.net/11328/2711.
Full textAbstract:
O objetivo da presente dissertação de mestrado tem como finalidade, em primeira análise, realizar uma abordagem a nível global à temática do tráfico de estupefacientes, para demonstrar a relevância que este problema tem e que afeta todos os países, especificamente ao nível ibérico.
Far-se-á uma alusão à importância da livre circulação no âmbito do espaço Schengen, não esquecendo, de igual modo, as implicações decorrentes da livre circulação na União Europeia bem como o seu reflexo na cooperação judiciária internacional no âmbito criminal.
Identificam-se as principais rotas internacionais de tráfico de estupefacientes que utilizam Portugal e Espanha como portas de entrada para o território europeu.
Explicitam-se as técnicas especiais de investigação e a sua relevância no âmbito da investigação criminal neste tipo de crimes, incidindo especificamente o estudo no âmbito dos meios excecionais de obtenção de prova, mais concretamente nas entregas controladas.
Neste sentido efetua-se uma análise do conteúdo normativo daquele meio de prova na Convenção de Nova Iorque demonstrando a relevância das entregas controladas como instrumento normativo a nível processual no âmbito internacional.
Por último, analisamos o regime jurídico de Portugal e Espanha, encontrando, naturalmente, pontos de encontro e de harmonia legislativa no que às entregas controladas e técnicas de investigação diz respeito, confirmando a relevância daqueles meios de obtenção de prova no âmbito da cooperação em matéria penal entre os dois países.The purpose of this Master's thesis is to analyze the issue of drug trafficking at the global level in order to demonstrate the relevance of this problem to all countries. So, later, we can focus on the Iberian level. As a result of this, we will allude to the importance of the Schengen area in the development of this study, not forgetting also the implications arising from it in the European Union reflected in international judicial cooperation in criminal matters. In a subsequent phase, we removed from the most recent annual report of the “Polícia Judiciária”, in this case relative to 2017, the main international drug trafficking routes that use Portugal and Spain as gateways to European territory. This will lead to an exposition of the special techniques of criminal investigation in order to deal with this delinquency, essentially proof, prohibited proof, and of course, the means of proof admitted in our legal system. Then we will study the subject of exceptional means of obtaining proof, more specifically to controlled deliveries, with the other exceptional means of obtaining proof being excluded for reasons of work dimension, thus allowing to maintain focus exclusively on controlled deliveries. Consequently, we will outline the content of the “Convenção de Nova Iorque” demonstrating that it has as its primordial objective the procedural regulation of controlled deliveries. Finally, we analyze the legal regime of Portugal and Spain, finding, naturally, points of convergence and legislative harmony in terms of controlled deliveries and research techniques, resulting in genuine cooperation in criminal matters.