This thesis investigates the design of a strip tension regulator by analytical techniques. The tension transfer function is non-linear and is derived for two conditions, first with only elastic deformation in the strip, and second with plastic flow in the strip resulting from reduction in the roll bite. The resulting transfer function consists of the one developed for elastic deformation with a degenerative feedback around it. This feedback is a result of reduction in the roll gap. The block diagram of the tension system reduces to a form containing two non-linear expressions. One is a second order equation describing the load and the other is third order equation describing the motor and the load effect on it. The motor is linearized by the addition of a high response armature current regulator. The tension regulator then reduces to a type I third order system. To compensate for the second order non-linearity in the regulator, a non-linear second order lead circuit is developed. This lead is modified continually as a function of strip velocity as well as coil radius and inertia. With the addition of this compensation, the tension regulator can be analyzed as a type I, first order system. / M.S.

AC main drives, such as cycloconverters, offer the possibility of higher speed and torque response over their DC counterparts. The price to be paid, however, is torque ripple which is a function of the operating frequency. Even a small value of ripple, at an underdamped plant resonant frequency, may be multiplied by the plant "Q" to a large enough value to cause trouble. Typical classical approaches used in the rolling mill industry to deal with mechanical resonance tend to fall apart with large values of time lag. We investigate a modified LQR/LQE approach using a torque sensor as the feedback element. The result is a low order SISO filter that suppresses the effects of the torque ripple on the underdamped plant. / Master of Science

The problem is to determine the status of the methods of inventory valuation in Texas Cotton Mills. This study is also conducted to determine how much uniformity, if any, exists in this particular industry.

No / The University of Bradford was constructed in the 1960s, following the demolition of Victorian streets, houses, and local community buildings. An on-campus archaeological excavation took place in 2021 as a result of Covid-19 restrictions. Using a variety of archive sources, the results of the Dig led to an armchair exploration of both former Victorian residents and also the social history of the former community. This reflective piece documents the archive journey taken by someone who is not an archaeologist and touches upon the experiences of heritage attachment. / University of Bradford, School of Social Sciences Research Fund

No description available.

At the end of 16th century an unique document had been preparing on the Rozmberk's estates. The Description of Mills from the year 1590 registers all Rozmberk's water mills in the south part of Bohemia. Thanks to this Description Jaroslav Honc published in 1959 an article that dealt with the concept of zoning of Rozmberk's milling in 1590. The main goal of the master's thesis is presentation of this very interesting source and comparison reformative Rozmberk's officers' ideas with the fact emerged from the study of accounting books of Třeboň estate between years 1550 and 1615.

M.Sc. / The lower Thukela River catchment supports the highly industrialised Mandini/Sundumbili Industrial Complex, which in turn supports Tugela Rail, a textile factory, a vegetable-oil factory, as well as the Sundumbili Sewerage Treatment works. All of these industries release their wastes into the Mandini River that leads into the lower Thukela River. Another major potential impacting factor on the lower Thukela River is the Sappi Tugela pulp and paper mill that has both abstraction and discharge points in the same region. In 2004 the Department of Water Affairs and Forestry completed a comprehensive Reserve Determination study for the Thukela River. Upon reviewing the results it was clear that many of the variables assessed were of low confidence or there was not sufficient data collected within the region of the Mandini and Thukela River confluence and further downstream (Resource Unit K). Therefore the previous studies were not able to determine the degree to which the industries in the lower Thukela system impacted upon the integrity of the system. The aim of this study was therefore to assess the contributing impacts of the Tugela pulp and paper mill and other industrial activities on the ecological integrity of the lower Thukela River. This was done by through a toxicity assessment of the potential impacts of effluent and wastewater using the Direct Estimation of Ecological Effect Potential (DEEEP) methodologies. The toxicity of pulp and paper effluent from the Thukela mill and the receiving water body was compared to effluents from two other mills (Stanger and Ngodwana), assessing the water quality in relation to the input of different industrial effluents in the lower Thukela River. The general integrity of the lower Thukela River in relation to the input of different industrial effluents was assessed using the Habitat Quality Index (HQI), Habitat Assessment Index (HAI), macroinvertebrate and fish population studies. These studies were integrated to derive the Ecostatus of the lower Thukela River using the Macro-invertebrate and Fish Response Assessment Indices (MIRAI and FAII respectively). The toxicity testing (DEEEP) showed the paper mill effluent in the Mandini River was the least hazardous whilst Ngodwana effluent showed the highest potential to elicit a harmful impact on the receiving water body. The latter effluent displayed the highest LC50 values for the fish and the Daphnia toxicity tests, as well as an extremely high base-pair substitution mutagen activity. Toxicity was also found in algae at 100% raw effluent exposure. Tugela and Stanger mill effluent samples were very similar in their toxicity, except that Stanger effluent showed greater mutagenicity potential with exceptionally high values of revertants. The Tugela effluent samples showed no concerning levels of mutagenicity. The fish showed lower levels of response to the Tugela sample when compared to the Stanger sample. Thus comparatively the Thukela system is regarded to be the least at risk with regards to effluent discharge into the receiving water body. The lower Thukela River integrity assessment showed a sharp increase in temperature below the discharge point of the pulp and paper mill effluent. This was attributed to the excessive temperatures recorded in the pulp and paper effluent itself. There was further decrease in dissolved oxygen, which was due a combination of the industrial waste water in the Mandini River and the pulp and paper effluent. The increased organic content in the sediments of the lowest site situated downstream (TR5) is a combination of both reduced velocity of the stream flow entering the upper reaches of the estuary as well as increased organic material entering the river via the pulp and paper effluent and the Mandini River above TR3-D. This was accompanied by increased contribution of fine particle size sediments to the overall sediment composition. Habitat conditions were near natural at sites upstream of the Mandini River and effluent discharge confluences with the Thukela River. The exception was at TR1 as the weir results in unnatural inundation of biotopes upstream. The habitat conditions around the confluences of the Mandini River and pulp and paper mill effluent discharge are diminished with a recovery noted further downstream at TR4 and TR5. Invertebrate assessment shows the upstream sites to be natural, while the impact sites were largely to seriously modified. Once again the downstream sites (TR4 and TR5) show an improvement to recover to a moderately modified state. The fish assessment also shows a decrease in the FAII score below the impacts when compared to the integrity above the impacts. However these results are of low confidence due to insufficient sampling effort as only electronarcosis, seine and cast nets were used. The Ecoclassification assessment indicated a clear decrease in Ecostatus between the sites that are upstream of the impacts caused by the industrial effluent from the Mandini River and the pulp and paper mill effluent from the effluent discharge stream. The MIRAI also clearly indicated that the major impacts are caused by the combination of the Mandini River and the pulp and paper effluent. However there was a recovery in the river further downstream from the impacts.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Alguns aspectos não perturbativos das teorias de Yang-Mills puras em quatro dimensões Euclideanas, quantizadas no calibre de Landau, são estudados analiticamente. Por pura entendemos a teoria na ausência de matéria (férmions). Em particular, ivestigamos a geração dinâmica de massa para os gluons devido a presença de condensados de dimensão dois. Este estudo é feito utilizando a técnica de operadores locais compostos no caso da ação de Yang-Mills, bem como, no caso da ação de Gribov-Zwanziger. Além deste estudo, uma investigação sobre as ambigüidades de Gribov nos calibres lineares covariantes é apresentada. No caso da ação de Yang-Mills, fizemos uma análise detalhada da técnica de opera-dores locais compostos quando introduzidos, simultaneamente, os operadores A&#956;aA&#956;a e fabcc*bcc. Através da teoria da renormalização algébrica, provamos a renormalizabilidade do modelo a todas as ordens em teoria de perturbações. Com o auxílio das equações do grupo de renormalização uma ação quântica efetiva é construída para os condensados <A&#956;aA&#956;a> e <fabcc*bcc>. Esta construção é feita utilizando a regularização dimensional em conjunto com o esquema de renormalização MS. Mostramos que um valor não trivial para estes condensados é favorecido dinamicamente, independentemente da escala escolhida. Cálculos explícitos, a um laço, são apresentados fornecendo estimativas numéricas para estes condensados e para a energia do vácuo. Através de um estudo via identidades de Ward, somos capazes de mostrar formalmente que a presença do condensado Overhauser, <fabcc*bcc>, é responsável pela quebra de transversalidade da polarização do vácuo. Contudo, o propagador do glúon permanece transverso, a todas as ordens em teorias de perturbações. Finalmente, esta análise é terminada com o cálculo explícito da correção, a um laço, à massa do glúon, devido a presença destes condensados. O resultado é que existe uma quebra na degenerescência da massa entre gluons Abelianos e não Abelianos. Esta quebra, devido a massa não Abeliana ser maior que a Abeliana, pode ser interpretada como uma evidência da dominância Abeliana no calibre de Landau. Com relação à ação de Gribov-Zwanziger sem a inclusão de condensados, começamos por efetuar cálculos explícitos. Mostramos formalmente que, a um laço, a energia do vácuo será sempre positiva, independentemente do esquema de renormalização escolhido e da escala. Apresentamos uma discussão sobre a procura de soluções da condição de horizonte no esquema MS, a um e dois laços, e as respectivas dificuldades encontradas. Em seguida, mostramos, através da teoria de renormalização algébrica, que a inclusão do operador A&#956;aA&#956;a na ação de Gribov-Zwanziger via o formalismo LCO é renormalizável a todas as ordens em teoria de perturbações. Tentativas de resolver as equações de gap são apresentadas no esquema de renormalização MS a um laço. Mostramos formalmente que, para a condição de horizonte, não existem soluções para <A&#956;aA&#956;a> < 0 e somente uma solução para <A&#956;aA&#956;a> > 0 pode existir. Contudo, no esquema MS, não fomos capazes de encontrar esta solução explicitamente. Desta forma, uma aprimoração do esquema de renormalização é feita de forma a minimizar a dependência no esquema escolhido. Nesta otimização encontramos a solução no limite MS bem como para o caso em que a dependência no esquema de renormalização é mínima. Em ambos os casos, a energia do vácuo se mostra positiva e o condensado <A&#956;aA&#956;a> > 0. Após os cálculos explícitos, uma discussão sobre as conseqüências físicas de um parâmetro de Gribov não nulo é apresentada. Finalmente, apresentamos um estudo das ambiguidades de Gribov nos calibres lineares covariantes para o caso em que &#945;<<1, onde &#945; é o parâmetro de calibre. Após identificar uma região no espaço funcional das configurações na qual não existem cópias de Gribov próximas, efetuamos a respectiva restrição da integral de caminho. Como efeito no nível árvore, o propagador do glúon transverso se torna suprimido no limite infravermelho devido a presença do horizonte de Gribov. A componente longitudinal se mostra suprimida devido a geração dinâmica de massa, associada ao condensado <A&#956;aA&#956;a>. Ainda, diferentemente do calibre de Landau, o propagador dos campos fantasmas não apresenta conexão com forças de longo alcance. Em contrapartida, uma função de Green singular no infravermelho, relacionada ao horizonte, é identificada e pode ser associada a forças de longo alcance. Por fim, todos os resultados do calibre de Landau são recuperados no limite &#945;&#8594;0.. / Some nonperturbative aspects of Euclidean Yang-Mills theories in four dimensions,quantized in the Landau gauge, are analytically studied. In particular, we investigate the dynamical mass generation for the gluons due to the presence of dimension two condensates. This study is performed in the framework of the local composite operator technique in the case of the Yang-Mills action as well as in the case of the Gribov-Zwanziger action. Further, an investigation of the Gribov ambiguities in the linear covariant gauges is presented. In the case of the Yang-Mills action, we perform a detailed analysis of the local composite operator formalism when the operators AaAa and fabccbcc are simultaneously introduced. Using the algebraic renormalization theory, we prove the renormalizability of the model trough all orders in perturbation theory. With the help of the renormalization group equations, a quantum efective action for the condensates <AaAa> and <fabccbcc> is constructed. This construction is performed by means of the dimensional regularization in the MS renormalization scheme. We show that non vanishing condensates values are dynamically favored, independently of the chosen scale. Explicit one loop computations are then presented, providing estimates for the condensates as well as for the vacuum energy. With the help of suitable Ward identities, we are able to normally show that the presence of the condensate <fabccbcc> is responsible for the breaking of the transversality of the vacuum polarization. However, the gluon propagator remains transverse, trough all orders in perturbation theory. Finally, we end this analysis with the explicit computation of the one loop correction to the efective gluon mass. The result is that, due to the condensate <fabccbcc>, the Abelian and the non Abelian sectors acquire diferent masses. Since the non Abelian mass is larger than the Abelian one, this feature can be interpreted as an evidence for the Abelian dominance principle in the Landau gauge. With respect to the Gribov-Zwanziger action, we start our analysis without taking into account the condensate. We show that, at one loop order, the vacuum energy is always positive, independently of the renormalization scheme and scale. We also present attempts to solve the one and two loops horizon condition in the MS scheme, and also the respective obstacles of it. Later, using the algebraic renormalization theory, we show, to all orders in perturbation theory, the renormalizability of the Gribov-Zwanziger action when the composite operator AaAa is included in the framework of the local composite operator technique. Attempts to solve the one loop gap equations in the MS scheme are then presented. We show that there are no solutions for <AaAa> < 0 while for <AaAai> 0 there is only one possible solution for the horizon condition. However, in the MS scheme, we were not able to find explicitly that solution. As an improvement, an optimization of the renormalization scheme is performed in the sense of minimizing the renormalization scheme dependence. In that approach the MS limit solution was found as well as the solution with minimal dependence on the renormalization scheme. In both cases, the vacuum energy shows itself to be positive while the condensate <AaAa> > 0. A discussion of the consequences of a nonvanishing Gribov parameter is then provided. Finally, we present a study of the Gribov ambiguities in the linear covariant gauges for the case &#945;<<1, where &#945; is the gauge parameter. After the identification of a region in field space where there are no close Gribov copies, we perform the respective restriction in the path integral. As a tree level efect, the transverse gluon propagator turns out to be infrared suppressed, due to the presence of the Gribov horizon. The longitudinal component shows itself to be infrared suppressed due to the dynamical mass, associated with the condensate <AaAa>. Further, diferently of the Landau gauge, the ghost propagator is not related to the appearance of long range forces. Instead, an infrared singular Green function related to the Gribov horizon is identifed. This Green function can be associated with long range forces. At the end, all Landau gauge results can be recovered taking the limit &#945;&#8594;0.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta tese estudamos uma extensão supersimétrica do mecanismo de Gribov no caso N = 1 em supercampos. Abordamos as teorias de super Yang-Mills em D = 4 e super Yang-Mills-Chern-Simons em D = 3. E verificamos como nestes casos o princípio de calibre leva ao cenário de confinamento de Gribov. / In this thesis we study a supersymmetric extension of the Gribov mechanism in the case of N = 1 with superfields. We approached the theories of super Yang-Mills in D = 4 and super Yang-Mills-Chern-Simons in D = 3. And we verify how in these cases the gauge principle leads to Gribov confinement scenario.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta tese estudamos uma extensão supersimétrica do mecanismo de Gribov no caso N = 1 em supercampos. Abordamos as teorias de super Yang-Mills em D = 4 e super Yang-Mills-Chern-Simons em D = 3. E verificamos como nestes casos o princípio de calibre leva ao cenário de confinamento de Gribov. / In this thesis we study a supersymmetric extension of the Gribov mechanism in the case of N = 1 with superfields. We approached the theories of super Yang-Mills in D = 4 and super Yang-Mills-Chern-Simons in D = 3. And we verify how in these cases the gauge principle leads to Gribov confinement scenario.