71 |
Přesnost nakládky do závěsného vertikálního míchacího krmného vozuKADLEC, Ondřej January 2018 (has links)
The theoretical part features an overview of the historical development of dairy cows feeding and introduces currently used trends in feeding. This part also outlines basic technologies in the production of roughage and describes modern feed distribution machinery. The practical part evaluates the accuracy of loading of individual components and the total weight of a feed ration loaded into a vertical suspension mixer feeder wagon by a front-end loader tractor. The observation was carried out at Mr. Kadlec's family farm in Velký Bor near Netolice and lasted four months. During this period, the actual weight of loaded components (grass-clover haylage, maize silage, grains meal) was being monitored daily. The evaluation came to a conclusion that grass-clover haylage stored in bales is loaded with a greater accuracy than maize silage stored in a clamp silo.
|
72 |
Projekt logické ochrany přípojnic / Project of Logical Busbar ProtectionKulač, Ivan January 2013 (has links)
The main objective of master‘s thesis was creation logical overcurrent busbar protection. The first part of document describes teaching test panels with ABB REF feeder protection´s terminals. These panels are installed in Laboratory of electrical protections at Department of electrical power engineering, Faculty of electrical engineering and communication, Brno University of technology. On these panels we can simulate the real involvement of the distribution station. Were subsequently describes used digital protection´s terminals REF 543. Then was designed configuration of these panels so to achieve logical busbar protection, which will be able to assess the short circuit fault and shut the smallest part of the busbar system. Within the configuration it was necessary to solve the cooperation of protection terminals. This was finally accomplished through connecting wires between each test panel. After the configuration it was necessary make the tests. We used secondary protection tester CMC 256plus. After the tests was analysis fault´s records and has been verified the accuracy of the proposed logical busbar protection.
|
73 |
Vady a vlastnosti masivních odlitků / Defects and properties of heavy castingsSobotka, Petr January 2012 (has links)
A diploma thesis was objected to a figure analyzing and a figure interpretation of ingot processing. The described figures were obtained from samples which were taking from feeder-heads of ingot of lower ram, produced in Vitkovice Machinery Group. The thesis was focused on ingot solidification and segregation processes which were associated with this procedure. The figures obtained from numeric simulation of ingot solidification in defined places were analyzed using statistic method – linear regression, as well as linear regression was used for evaluation of explored samples, their chemical compositions and mechanical properties. In conclusion all acquired results were summarized.
|
74 |
Modeling Biomass Transport in a Compression Screw FeederNathaniel Hall Gasteyer (9234404) 12 August 2020 (has links)
<p>Biorefineries which seek to convert biomass into ethanol face many different challenges, and among them, mechanical failure of equipment is common. Unfortunately, the resulting downtime can significantly reduce the profitability and the viability of bioethanol plants. One important piece of mechanical equipment in this setting is the compression screw feeder, which is used both to convey and compress biomass into pressurized chemical reactors. However, due to the variability of feedstock properties, this feeding operation is challenging. An analytical model for predicting the operational steady-state torque of a compression screw feeder can assist the identification of optimal processing conditions, as well as predict and prevent equipment failure.<br></p>
<p>Since
these models have not yet been proposed, this thesis restricts attention to
milled corn stover and investigates the application of the discrete element
method (DEM) and analytical techniques to develop predictive models for the
stresses and torques developed inside a compression screw feeder. Specifically,
DEM simulations are used to identify and study the stresses within the
different sections of a representative compression screw feeder for three
backpressures, three screw pitches, and three internal friction angles. Using these numerical results, a suite of analytical
models is then developed to predict the operational torque required to drive
the screw feeder. In this thesis, the DEM results are also used in lieu of
experimental data to provide a point of comparison for the models.</p>
<p>The analytical models predict stresses on the correct order
of magnitude and are not prohibitively sensitive to input properties, but the
operational steady-state torque is overpredicted by the model in all cases. The
mispredictions of the model are likely due to the assumption of constant
material properties along the densification process, and the assumption of
hydrostatic conditions throughout the compression screw feeder (especially near
the boundaries). Despite these limiting assumptions, the proposed procedure for
calculating the torque provides a first-order estimate of the required screw
torque, demonstrates the sensitivity of the screw feeder to different inputs,
and outlines the necessary steps to improve the model. The DEM simulations
proved an invaluable tool in analyzing the behavior of bulk material within a compression
screw feeder, but more experiments and simulations (possibly using the finite
element method) are needed to further understand the biomass feeding operation.</p>
|
75 |
Great Eggs-pectations: Understanding Markers of Stress and Welfare in Pullets Using Feeder Space and Stocking Density StressorsMeagan E Abraham (14206337) 09 December 2022 (has links)
<p> </p>
<p>Little is known about pullet stress and welfare and even less is known about pullets in cage-free housing. The studies included in this dissertation evaluated bird responses to stocking density, feeder space, and ACTH stressors in pullets. The project and procedures were reviewed and approved by the Purdue University Animal Care and Use Committee (Protocol#:2001002002 and # 1908001938). </p>
<p>Two studies of external stressors and one study of an internal stressor were applied to Lohmann LB-Lite (Brown) and Lohmann LSL-Lite (White) pullets. For both studies of an external stressor, bird-based welfare parameters included evaluation of bird appearance through feather coverage, foot condition, and keel condition; blood parameters, i.e., cholesterol, corticosterone, cortisol, NDV/IBV IgG/IgY titer, and differential WBC (%) and heterophil to lymphocyte ratio; measurements of the spleen, bursa, thymus, and liver; and production values measured through body weight, body weight uniformity, shank length, feed consumption, and feed conversion ratio (FCR). Birds were followed from 2-16 weeks of age (WOA) for the external stressors and were housed on the floor.</p>
<p>The first external stressor was applied through a 2 x 2 factorial randomized complete block design (RCBD) using Brown and White strains and two stocking densities- high (HSD) and low (LSD). Stocking densities were adjusted over time, with the ending density of 670 cm2/bird for HSD and 1352 cm2/bird for LSD at 16 WOA. Density alone affected relative bursal weight (%), with LSD generating heavier bursas. LSD also generated lower, better FCR for both white and brown strains though this difference was not statistically significant. Within a density, opposing strain effects were seen for body weight uniformity and feather coverage. White was improved at HSD while Brown was improved for LSD. </p>
<p>The second external stressor study was a 2 x 2 x 3 factorial RCBD with Brown and White, 2 feeder space allocations (3.5 or 7 cm/bird), and 3 stocking densities. The ending stocking densities were 154.45, 518.76, and 1,247.38 cm2 for the high (HSD), medium (MSD), and low (LSD) stocking density treatments, respectively, at 16 WOA. In this study, less space per bird was associated with poorer feather condition but improved FCR. Reduced feeder space was associated with elevated or worse FCR.</p>
<p>In a study of internal stressors, ten each of Lohmann LSL-Lite hens received either a saline-mannitol or synthetic human ACTH injection at 6, 17, and 26 weeks of age. Blood was collected prior to injection and 1- and 2-hours post-injection. H:L ratio, WBC differential counts, corticosterone, and cortisol were measured in blood. Albumen samples were collected to measure corticosterone and cortisol at 26 WOA only but were unaffected by treatment. Serum corticosterone and H:L ratio were also unaffected by treatment. Serum cortisol was increased 1 hour after ACTH injection at 17 and 26 WOA and percent heterophils and lymphocytes were affected by ACTH at 26 WOA indicating potential utility as a measure of stress for adult birds only. </p>
<p>The results of these studies show that pullets are resilient and resistant to several stressors. Both acute and chronic as well as internal and external stressors were tested in these studies with limited effects on the birds’ physiology, immunity, condition, or production. Feather coverage and bursal size were improved at lower stocking densities and FCR was improved at greater feeder space but the implications of these differences are unclear. Further research is needed to identify why there are reduced stress responses in pullets; it is possible that domestication or preserved evolutionary pathways explain some of the differences between pullet and adult stress responses. And while the majority of parameters were unaffected by the stressors used, the results of this study presented baseline values for Lohmann LB-Lite and Lohmann LSL-Lite pullets that will help guide future research. Additionally, the results of these studies left perhaps more questions than answers but illustrate perfectly that more research will be critical to an understanding of pullet stress and welfare.</p>
|
76 |
The support of undifferentiated human embryonic stem cell lines by different matricesKhadun, Shalinee January 2014 (has links)
The future of human embryonic stem cell (hESC) research with regards to their applicability in a therapeutic setting, relies on the development and standardisation of consistent and robust methods to demonstrate their defining characteristics; their pluripotent ability to form all three germ layers and their capacity for self-renewal. Although much research has been carried out to investigate new methods of culturing hESCs, many of these studies have not robustly concluded the impact of prolonged culture on genetic and genomic stability nor have they examined in any comparative detail the impact of the culture conditions such as differences in feeders used or the media composition in which the stem cells are cultured in. The aim of this thesis therefore was to investigate and evaluate methods for improving the uniform and robust culture and characterisation of hESCs over prolonged periods in culture. Four hESC lines ( RH5, HUES9, SHEF1 and NCL5) were chosen on the basis that they had not previously been well characterised and therefore could potentially benefit the wider stem cell community by increasing diversity, rather than continue to use the already small subset of well publicised lines. The RH5, HUES9, SHEF1 and NCL5 cells were subjected to long term passaging using recombinant enzyme TrypLE™ Express, on human feeders, mouse feeders and feeder free matrix Matrigel in combination with defined media mTeSR1, for uniform scale up. Changes in characteristic stem cell surface markers were compared using two techniques; flow cytometry and quantitative in situ fluorescence microscopy. Genomic stability was assessed by real time PCR. Chromosomal integrity was monitored using array genomic hybridisation (aCGH). Array genomic hybridisation analysis of cells cultured for 20 passages by enzymatic passaging revealed changes in copy number variations in all the stem cell lines. Aberrations on chromosomes 12, 17 and 20, appeared most commonly as a result of long term culture. Although no significant differences were seen between hESCs cultured on mouse and human feeders, cultures on Matrigel showed fewer detected chromosomal aberrations. Expression of cell surface stemness markers SSEA3, SSEA4, TRA1-60 and TRA1-81 were maintained by hESC cultured on all matrices and confirmed by the use of flow cytometry and high throughput quantitative immunofluorescence imaging using the TissueFaxs™ cell analysis microscopy system. In depth imaging revealed subtle but important differences in the way in which hESCs attach and proliferate on different matrices. Genetic profiling of each of the stem cell lines using Taqman Low density array cards to assess the expression of 96 genes by Real Time PCR, demonstrated the continued expression of stemness genes 21 at late passage, and low level expression of differentiation genes, inherent to particular stem cell lines. Although both mouse and human feeders and Matrigel support the undifferentiated growth of hESCs, subtle differences from the hESCs were seen as a result of their use, most obviously, changes in morphology and how they proliferate. This was further explored in the stem cell line NCL5, as it demonstrated a readiness to adapt to new matrices, better chromosomal stability and higher expression of cell surface markers compared with the other hESC lines. Using in vitro differentiation assays to all three germ layers, NCL5 cultured to late passage (p+20) on human feeder iMRC5, mouse feeder iMEF and feeder free matrix Matrigel, demonstrated the ability to differentiate to ectoderm, endoderm and mesoderm progenitors after induction using three 7 day flat based directed differentiation protocols. Altered differentiation patterns were detected by Real Time PCR and TissueFaxs™ imaging and quantitative analysis, as a consequence of the prolonged culture on the specific matrices used. Such key findings allude to the strong influences of microenvironment and will help to improve the standardisation of in vitro differentiation assays. From these studies, chromosomal changes had no impact on NCL5 stem cell lines‘ ability to form progenitors, however small genetic instabilities may still play a role in terminal differentiation of germ lineage specific cell types. The findings of the programme of work described has led to the successful culture methods and characterisation testing validated in this project being incorporated into routine culture and banking of research grade hESCs at the UK Stem Cell Bank. These protocols will now be made more widely available and should assist stem cell researchers in adopting the most suitable and optimum conditions for culturing stem cells in the undifferentiated and stable state. With the huge surge in stem cell research over the past decade, the development of robust characterisation and culture methods will undoubtedly have significant impact on the exploitation of these cells for regenerative medicine and to assist with this a future aim of the stem cell bank will be to standardise methodologies for clinical grade banking.
|
77 |
Theoretical modeling of single-phase power electronics loads to predict harmonic distortion at a distribution feeder network using a reverse optimization solutionKapur, Virat 21 June 2010 (has links)
Proliferation of non-linear, single-phase power electronics loads, such as personal computers, television sets, CFLs, has resulted in thousands of individual small harmonic current injectors connected to a distribution feeder network. Harmonic standard: IEC 1000-3-2 classifies such loads as Class D, “low-voltage” equipment with current emissions limited to 16A/Phase. Individual harmonic contributions of such loads appear insignificant; their collective contribution, however, is a matter of concern. The average order of voltage distortion usually varies between 4-6%; current distortion, however, is usually of the order of 100%. Limitations and high-costs associated with conventional harmonic mitigation measures, has furthered the need for regulation and alternative strategies. The objective of this research is to predict, and mitigate the effects of harmonic proliferation in the main supply current measured at the point of common coupling (PCC). An equivalent circuit model – an aggregation of single phase power electronics loads connected to the distribution feeder network is proposed as a part of a forward solution. Each load, individually, behaves as a harmonic current source; the proposed model combines these individual harmonic current injectors into a single harmonic source connected at the PCC and their collective contribution as a single composite harmonic signal. It represents harmonic conditions at the PCC and provides a theoretical measure of harmonic distortion in the supply current. Such a model finds application during harmonic compliance testing for single-phase power electronics loads; it simulates and predicts the harmonic response of such loads using a theoretical pure 60 Hz sine wave as the supply voltage diffcult to obtain physically, yet critical to such tests. The accuracy of the equivalent circuit model in predicting a harmonic response is pivotal to a successful forward solution. A feed-backwards mechanism is proposed. For a given harmonic supply voltage and circuit configuration of the equivalent circuit model, the feed-backwards method generates the modeled response and compares it to a reference physical response. Finally, it optimizes the circuit configuration to a unique Correction Factor that facilitates an accurate modeled response. Three optimization algorithms, labeled as Response Optimization algorithms have been developed to execute the feed-backwards mechanism. These algorithms are written in FORTRAN-90. / text
|
78 |
Využití "Amodal completion" při rozpoznávání predátorů: vliv na riskování / The use of amodal completion inpredators recognition: effect on risk takingSedláčková, Kristýna January 2012 (has links)
Amodal completion enables animals (birds, mammals, but also fish) to perceive partly occluded objects as whole. Most of the studies focusing on the occlusion phenomenon were carried out in a laboratory and were based on either operant conditioning or filial imprinting techniques. This study concentrates on behavior of untrained animals in their natural habitat. Pairwise preferential experiments were used to reveal responses of tits (the great tit, Parus major; the blue tit, Cyanistes caeruleus; the marsh tit, Poecile palustris) to two dummies placed near an experimental and an alternative feeder. The dummies used were the complete dummy of a sparrowhawk and a pigeon, and partly occluded (the lower or upper torso hidden in shrubs) and amputated (only lower or upper torso on the perch) models of sparrowhawks - 15 combinations altogether. The tits considered all variants of torsos to be predators. The great tit and the blue tit perceived the model with occluded lower torso as more dangerous than the one with amputated lower torso. Such discrimination between these torsos requires the ability of amodal completion. The great tit also confirms this ability as it regarded the complete sparrowhawk and the model with occluded lower torso as equally dangerous. In the remaining cases, the number of arrivals...
|
79 |
Jsou velikost těla a druhově specifické zbarvení důležitými znaky pro rozpoznávání predátorů potenciální kořistí? / Are body size and specific species colouration important cues for predator recognition by their potencial prey? Diplomová práceAntonová, Kateřina January 2018 (has links)
I tested influence of a body size and overal colouration in feeders experiments on recognition of sparrowhawk (Accipiter nisus) by chosen species of passerine. Experiments were conducted in years 2015 ̶ 2018. I used a plush dummies which carried a specific featuress of raptor (hooked beak, claws) and specific features of genus Accipiter (yellow eyes, respectively yellow eyes and overal colouration). As a control, dummy of harmless pigeon was used. Smaller dummies (size of a great tit) were not recognized as a raptor regardless of colouration. Large dummies with colouration of great tit and pigeon were not recognized as a raptor as well. On a contrary, large dummy with colouration of robin was recognized as a raptor, respectively sparrowhawk. Most birds who were flying to the feeders, at first payed attention to global features (size, overal colouration). If these features belong to well-known harmless bird, then local features (particular) which characterize raptor or sparrowhawk had no effect. Birds did not pay attention to them. Therefore it depends on a context, in which potential local key features occure.
|
80 |
Bem-estar animal na cadeia produtiva: avaliação de sistemas de alojamento na gestação da suinocultura e percepção do consumidor / Animal welfare in the production chain: evaluation of sow housing systems during gestation and consumers\' attitudesSato, Patrycia 07 April 2017 (has links)
A exigência de consumidores por alimentos originados de sistemas que forneçam boas condições de vida aos animais de produção consiste numa realidade em inevitável crescimento. Legislações internacionais elaboradas por demanda de mercado pressionam os produtores e a indústria brasileira a cumprir normas que estabelecem padrões mínimos de bem-estar animal (BEA). No caso específico da suinocultura, um dos aspectos mais polêmicos é o alojamento das matrizes durante a gestação. As gaiolas individuais, sistema convencional no Brasil, promove limitação física e social, além de predispor a distúrbios locomotores e comportamentais. Por outro lado, o sistema proposto para melhorar o BEA, as baias coletivas, provocam outros problemas, como as brigas por disputa hierárquica e por alimento, e o baixo controle individual, que poderiam prejudicar o desempenho reprodutivo. Dessa forma, um equipamento individual de arraçoamento automatizado (ESF) foi desenvolvido para amenizar essa situação. Para descobrir o efeito do alojamento em grupo com o ESF no desempenho reprodutivo das matrizes, foi realizada uma comparação de dados reprodutivos dos dois sistemas, localizados numa mesma propriedade. Dados mensais de três anos foram coletados dos registros das granjas e analisados por teste T-Student para as variáveis paramétricas e por teste de Mann-Whitney para as não paramétricas. De acordo com os resultados, o desempenho das matrizes alojadas em baias foi superior. Apenas a média do peso do leitão ao nascimento foi significantemente inferior em relação ao sistema individual, sugerindo que a conversão de sistemas é não apenas favorável ao BEA e ao mercado exigente, mas também para a produtividade. Além da questão do produtor, é essencial avaliar a percepção do consumidor brasileiro quanto ao BEA, visto que seu poder de compra é uma forte influência no mercado, e que apenas as exigências internacionais não são suficientes para provocar mudanças em todos os sistemas de produção do país. Por isso, também foi realizado um levantamento com consumidores. Utilizou-se dois métodos de coleta: online e em campo (pontos de comércio), para uma maior abrangência e representatividade. Os dados coletados foram analisados por estatística descritiva, e o teste Qui-quadrado foi aplicado para avaliar se houve associação entre a distribuição das respostas e o perfil dos participantes. Ambas as pesquisas demonstraram que o consumidor reconhece a senciência dos animais de produção, sente que é dada pouca importância ao tema no Brasil, enquanto consideram o governo como principal responsável por promover melhorias. Concordam que consumir produtos com certificação em BEA pode contribuir para melhorar as condições dos animais, apesar de não conseguirem identificar o selo nas embalagens. Além disso, apesar dos participantes alegarem não conhecer os sistemas de produção atuais, demonstraram interesse sobre o assunto e disposição para pagar mais por produtos certificados. No entanto, algumas respostas devem ser indagadas quando pareadas com o real comportamento do consumidor. / Consumer\'s demand for animal-friendly food is an inevitably growing reality. International legislation drawn up by market demand pressure Brazilian farmers and the industry to comply with minimum animal welfare standards. Specifically in pig production, one of the most controversial aspects is the housing of sows during gestation. Individual crates, which is the conventional system in Brazil, promote physical and social restriction, and predispose to lameness and behavioural disorders. On the other hand, group pens were proposed system to improve animal welfare, but bring other problems, such as hierarchical and food competition aggression, and low individual control, which could impair reproductive performance. In this way, electronic sow feeder (ESF) was developed to mitigate this situation. So, to find out the effect of group housing with ESF system on reproductive performance of sows, a comparison of reproductive data of both systems, located in the same farm, was performed. Monthly data of three years were collected from the farm records and analyzed by T-Student Test for parametric variables and Mann-Whitney Test for the non-parametric variables. According to the results, group housing showed better performance. Only piglet weight at birth was significantly higher in individual housing, suggesting that the conversion of housing systems is not only favourable to farm animal welfare (FAW) and to demanding market, but also to productivity. In addition to the farmer issue, it is essential to evaluate Brazilian consumer\'s perception of FAW, since his/her purchasing power causes strong impact on market. Besides, international legislation is not enough to bring about changes in all Brazilian farms and food industries. Therefore, a consumer survey was conducted. Two data collection methods were used: online and in loco (marketplaces). for greater number of answers and representativeness. Collected data were analyzed by descriptive statistics, and chi-square Test was applied to evaluate if there was association between answers\' distribution and participants\' profile. Both surveys have shown that consumer recognizes farm animals\' sentience, feels that little importance is given to the subject in Brazil, while he/she considers the government as the main responsible for promoting FAW. They agree that consuming animal-friendly products can help improve animals\' conditions, even though they cannot identify certification seal. In addition, while participants claim they are not familiar to farming systems, they have shown interest in the topic and willingness to pay more for certified products. However, some answers should be analyzed when paired with actual consumer behaviour.
|
Page generated in 0.0351 seconds