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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Estudo comparativo entre o método das tensões admissíveis e o dos estados limites para alvenaria estrutural / Comparative study between the allowable stress method and the limit state method for structural masonry

César Alexandre Varela Ataíde 25 April 2005 (has links)
A norma que prescreve o cálculo de alvenaria estrutural de blocos vazados de concreto, NBR 10837:1989, encontra-se em fase de revisão, sendo que a principal alteração é a introdução do método dos estados limites no dimensionamento e na verificação dos elementos de alvenaria. Neste trabalho, estudam-se duas normas para alvenaria, a NBR 10837:1989 e EC 6:1996, e o texto proposto para revisão da NBR 10837. A escolha do EC 6:1996 se deu pela sua importância em relação à comunidade européia e porque muitas das prescrições contidas nessa norma foram adaptadas para o texto de revisão da NBR 10837. Quando necessárias, são realizadas comparações entre as duas normas e o texto de revisão, com o intuito de auxiliar no entendimento das implicações que a mudança de abordagem causará. Vários exemplos que simulam situações típicas de projeto, como compressão simples, flexão e cisalhamento, são apresentados. Com a variação dos diversos parâmetros envolvidos no dimensionamento dos elementos de alvenaria, é possível a elaboração de gráficos e ábacos. Desta forma consegue-se englobar uma grande variedade de situações, e a comparação entre as respostas obtidas com cada uma das normas e com o texto de revisão torna-se bem mais simples e precisa. Pretende-se, com este trabalho, contribuir para a introdução do método dos estados limites na norma de cálculo de alvenaria estrutural, bem como avaliar as mais importantes adaptações propostas. / The code that regulates the design of concrete blockwork structural masonry, NBR 10837:1989, is under revision phase. The main change is the introduction of limit state method for the design and verification of masonry elements. In this work, two masonry codes (NBR 10837:1989 and EC 6:1996) and a proposed revised text for the NBR 10837 are studied. The choice for EC 6:1996 is justified by its importance to european community and because many clauses of the revised text are adapted from that code. When necessary, comparisons between the two codes and revised text are carried out, to help the understanding of the changes implications. Some examples, that simulate typical design situation, such as axial compression, bending and shear are presented. A parametric study on the masonry elements design is carried out, allowing for the elaboration of graphs and abacus. Thus, various situations are explored, showing different results corresponding to each one of the codes and the revision text, in order to clarify the comparisons. The general aim of this work is help the introduction of the limit state method in the masonry code, and to evaluate the most important changes in the proposed revised text of the brazilian code.
12

Dovolené riziko / Allowable risk

Šorf, David January 2016 (has links)
The topic of this diploma thesis is allowable risk and its impact as a potential circumstance excluding liability. Czech law system takes into account tolerable risk as a circumstance excluding liability which this thesis is substantially focused on. At the beginning of the thesis circumstances excluding liability are defined in order to compare specifics of the tolerable risk institute. Briefly it analyzes some basic criminal law questions related to the thesis subject including concept of crime or errors in circumstances excluding liability. Next chapters deal with legal and general definition of tolerable risk and historical development of this issue in our law environment, including work of August Miřička, probably the first Czech lawyer addressing this issue. Further questions are suggested in these chapters. These questions are derived from legal status of tolerable risk and are thoroughly discussed in separate chapters for each sector. Legislator did not restrict sectors of usage explicitly. If conditions stated in the criminal code are fulfilled, tolerable risk can be always used. Although the thesis focuses on sectors in which risk has been proven usable, potential list of fields of application is not totally exhausting. I also evaluate suitability of the definition of tolerable risk in...
13

Estudo comparativo entre o método das tensões admissíveis e o dos estados limites para alvenaria estrutural / Comparative study between the allowable stress method and the limit state method for structural masonry

Ataíde, César Alexandre Varela 25 April 2005 (has links)
A norma que prescreve o cálculo de alvenaria estrutural de blocos vazados de concreto, NBR 10837:1989, encontra-se em fase de revisão, sendo que a principal alteração é a introdução do método dos estados limites no dimensionamento e na verificação dos elementos de alvenaria. Neste trabalho, estudam-se duas normas para alvenaria, a NBR 10837:1989 e EC 6:1996, e o texto proposto para revisão da NBR 10837. A escolha do EC 6:1996 se deu pela sua importância em relação à comunidade européia e porque muitas das prescrições contidas nessa norma foram adaptadas para o texto de revisão da NBR 10837. Quando necessárias, são realizadas comparações entre as duas normas e o texto de revisão, com o intuito de auxiliar no entendimento das implicações que a mudança de abordagem causará. Vários exemplos que simulam situações típicas de projeto, como compressão simples, flexão e cisalhamento, são apresentados. Com a variação dos diversos parâmetros envolvidos no dimensionamento dos elementos de alvenaria, é possível a elaboração de gráficos e ábacos. Desta forma consegue-se englobar uma grande variedade de situações, e a comparação entre as respostas obtidas com cada uma das normas e com o texto de revisão torna-se bem mais simples e precisa. Pretende-se, com este trabalho, contribuir para a introdução do método dos estados limites na norma de cálculo de alvenaria estrutural, bem como avaliar as mais importantes adaptações propostas. / The code that regulates the design of concrete blockwork structural masonry, NBR 10837:1989, is under revision phase. The main change is the introduction of limit state method for the design and verification of masonry elements. In this work, two masonry codes (NBR 10837:1989 and EC 6:1996) and a proposed revised text for the NBR 10837 are studied. The choice for EC 6:1996 is justified by its importance to european community and because many clauses of the revised text are adapted from that code. When necessary, comparisons between the two codes and revised text are carried out, to help the understanding of the changes implications. Some examples, that simulate typical design situation, such as axial compression, bending and shear are presented. A parametric study on the masonry elements design is carried out, allowing for the elaboration of graphs and abacus. Thus, various situations are explored, showing different results corresponding to each one of the codes and the revision text, in order to clarify the comparisons. The general aim of this work is help the introduction of the limit state method in the masonry code, and to evaluate the most important changes in the proposed revised text of the brazilian code.
14

Irrigation and nitrogen management of African (Siphonochilus aethiopicus (Schweinf.) B.L. Burtt) and commercial ginger (Zingiber officinale Roscoe)

Gatabazi, Auges January 2019 (has links)
Medicinal plants are important and valuable natural resources. South Africa is well-endowed with very diverse flora and fauna that include a considerable number of medicinal plant species. Most medicinal plants have gained popularity for the treatment or prevention of various ailments. Ginger species (Zingiber officinale and Siphonochilus aethiopicus) are essential natural resources, which provide many useful products for use in food as a spice or as medicine. The two species contain beneficial secondary metabolites useful for treating many diseases and numerous digestive imbalances such as indigestion, vomiting, heartburn, diarrhoea and pregnancy-related nausea. However, the role of different agronomic practices such as irrigation, water stress and nutrient management are crucial for enhancing the yield and quality of ginger species. Due to climate change, rainfall is often less while more erratic, putting more pressure on irrigation resources in agriculture to sustain or even increase food production for a growing population. The major plant factors negatively affected by water limitations are plant growth, quality and crop yield. The second most constraining factor in plant growth and quality is the lack of plant nutrients. Macronutrients, such as N, P and K are most important in plants to complete their life cycle and play a significant role in the growth and development of plants. This study investigated the growth, yield and phytochemical profiling of two ginger species under different maximum allowable depletion levels of soil water content and nutrient management. The soil water study was conducted under a rain-shelter at the Experimental Farm on the Hillcrest campus of the University of Pretoria, South Africa. The experiment was laid out in a randomized complete block design (RCBD) with two factors (ginger species and water regimes) and three replicates per treatment. The two experimental factors included the two species of ginger (commercial and African ginger) and four water levels (irrigated as soon as 20-25% of available soil water (ASW) was depleted, 40-45% of ASW depleted, 60-65% of ASW depleted and 80-85% of ASW depleted). Growth and development parameters such as height, leaf number and stem number were evaluated and varied between species and irrigation treatments. Irrigation treatment effects on plant growth and development were dependent on plant species. Leaf area index and fractional interception of photosynthetically active radiation (FIpar) values were higher in African ginger than commercial ginger in both seasons. Scanning electron microscopy images showed that both ginger species had more stomatal pores and open stomata under well-watered than stressed conditions. The study demonstrated that fresh and dry yields were higher for commercial ginger, compared to African ginger. The fresh and dry matter yields for severely water stressed plants were higher for commercial ginger than for African ginger. Water use efficiency in terms of fresh commercial ginger yield was highest for the moderately water-stressed treatment. The severely water-stressed irrigation regime (i.e. 80-85 MAD) resulted in higher production of total flavonoid content, phenolic content and increased antioxidant activity in both species. / Thesis (PhD)--University of Pretoria, 2019. / Plant Production and Soil Science / PhD / Unrestricted
15

Development Of A 3-camera Vision System And The Saddle Motion Analysis Of Horses Via This System

Dogan, Gozde 01 September 2009 (has links) (PDF)
One of the purposes of this study is to develop a vision system consisting of 3 inexpensive, commercial cameras. The system is intended to be used for tracking the motion of objects in a large calibration volume, typically 6.5 m. wide and 0.7 m. high. Hence, a mechanism is designed and constructed for the calibration of the cameras. The second purpose of the study is to develop an algorithm, which can be used to obtain the kinematic data associated with a rigid body, using a vision system. Special filters are implemented in the algorithm to identify the 3 markers attached on the body. Optimal curves are fitted to the position data of the markers after smoothing the data appropriately. The outputs of the algorithm are the position, velocity and acceleration of any point (visible or invisible) on the body and the angular velocity and acceleration of the body. The singularities associated with the algorithm are also determined. Using the vision setup and the developed algorithm for tracking the kinematics of a rigid body, the motions of the saddles of different horses are investigated for different gaits. Similarities and differences between horses and/or gaits are analyzed to lead to quantitative results. Using the limits induced by the whole body vibration of humans, for the first time in the world, daily, allowable riding time and riding distances are determined for different horses and gaits. Furthermore, novel, quantitative horse comfort indicators are proposed. Via the experiments performed, these indicators are shown to be consistent with the comfort assessment of experienced riders. Finally, in order to implement the algorithms proposed in this study, a computer code is developed using MATLAB&reg / .
16

Mechanism Design For The Optimal Allocation Of Quotas And The Determination Of The Total Allowable Catch For Eu Fisheries Under An Age-structured Model

Kanik, Zafer 01 September 2012 (has links) (PDF)
In this study, we consider the mechanism design problem for the optimal allocation of fishing quotas at different total allowable catch (TAC) levels. An age-structured fish population model is employed. Fishing technologies are embedded in the economic model as a key determinant. As a result, we showed that the quota allocation mechanism is important to minimize the impact of fishing on total fish biomass or achieve maximum sustainable yield (MSY). Moreover, we indicated technology-based optimality conditions for allocation of quotas at different TAC levels, which minimize the impact of fishing on total fish biomass or enable us to achieve MSY. Under the consideration that the fishermen fulfill their remaining quotas through capturing untargeted (less revenue-generating) fish after the targeted fish population is fully caught, the fix ratio of the catch of targeted fish to untargeted fish is not valid anymore. Concordantly, we indicated technology-based optimal quota levels, including the interior solutions. In the EU, TACs are distributed among states according to the principle of &lsquo / relative stability&rsquo / which prescribes that the fishing quotas should be allocated based on historical catches of the EU states. In this context, rather than allocating the quotas based on historical catches, our main suggestion is that the structure of the fishing industry should be considered for allocation of quotas to provide the sustainability of EU fisheries and achieve responsible and effective management of the fishing industry in the EU.
17

Potential compliance impact of reduced permissible exposure limit for hexavalent chromium in an aerospace production and maintenance facility

Shamhart, Andrew Bradley. January 2006 (has links) (PDF)
Thesis--University of Oklahoma. / Bibliography: leaves 36-37.
18

Avaliação e diagnóstico de vias urbanas expressas de Manaus: condições estruturais e funcionais

Pinto Filho, Washington Luiz 29 November 2013 (has links)
Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-09-30T14:23:40Z No. of bitstreams: 1 Dissertação - Washington Luiz Pinto Filho.pdf: 8211076 bytes, checksum: 5b0146ee71fe71f4ffea30a9fca0f822 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-02T20:44:54Z (GMT) No. of bitstreams: 1 Dissertação - Washington Luiz Pinto Filho.pdf: 8211076 bytes, checksum: 5b0146ee71fe71f4ffea30a9fca0f822 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-10-06T19:53:40Z (GMT) No. of bitstreams: 1 Dissertação - Washington Luiz Pinto Filho.pdf: 8211076 bytes, checksum: 5b0146ee71fe71f4ffea30a9fca0f822 (MD5) / Made available in DSpace on 2015-10-06T19:53:40Z (GMT). No. of bitstreams: 1 Dissertação - Washington Luiz Pinto Filho.pdf: 8211076 bytes, checksum: 5b0146ee71fe71f4ffea30a9fca0f822 (MD5) Previous issue date: 2013-11-29 / Não informada / The city of Manaus has the highest average growth rates of the fleet, according to the DENATRAN. Over the past 10 years, the fleet of cars rose from 124,840 (2003) to 297,473 cars (2013) and 3,179 buses (2003) to 7,398 buses (2013). This equates to a 138% increase. Moreover, although, according to DENATRAN in 2003, Manaus was 220,816 vehicles. In 2013, Manaus already has 551,455 registered vehicles in its municipal fleet, which equates to an increase of almost 150%. As a result of this growth, the city roads are presented with its ability to flow and dead, visually, with their decks completely deformed. In this sense, we tried to carry this research, a structural evaluation of pavements of the main streets of the town (Av. Constantino Nery, Avenida Djalma Batista, Recife Av, Av and Av Efigênio Sales Paraíba), employing the technique FWD (Falling Weight Deflectometer) in the diagnosis of the pavement structures of these pathways. The results showed that the structures of those decks still have the condition to withstand the demands of traffic load applied to them, since their structural quality obtained by the mentioned technique, presented in good condition, according to the floors they presented deflections smaller than the allowed maximum, and radii of curvature much greater than 100 m. In addition, analysis was performed of the safety of the coating with respect to tire-pavement grip, which presented values for microtexture and macrotexture well outside the ranges recommended by the standards. / A cidade de Manaus apresenta uma das maiores taxas de crescimento médio da frota de veículos, segundo dados do DENATRAN. Nos últimos 10 anos, a frota de automóveis aumentou de 124.840 (2003) para 297.473 automóveis (2013) e 3.179 ônibus (2003) para 7.398 ônibus (2013). Isto equivale a um aumento de 138 %. Ademais, ainda, segundo o DENATRAN, em 2003, Manaus tinha 220.816 veículos. Em 2013, Manaus já possui 551.455 veículos registrados na sua frota municipal, o que equivale a um aumento de quase 150 %. Como consequência deste crescimento, as vias da cidade apresentam-se com sua capacidade de fluxo inoperante e, visualmente, com seus pavimentos totalmente deformados. Neste sentido, procurou-se realizar, nesta pesquisa, uma avaliação estrutural dos pavimentos das principais vias da cidade (Av. Constantino Nery, Av. Djalma Batista, Av. Recife, Av. Paraíba e Av. Efigênio Sales), empregando a técnica FWD (Falling Weight Deflectometer) no diagnóstico das estruturas dos pavimentos das referidas vias. Os resultados obtidos mostraram que as estruturas daqueles pavimentos ainda apresentam a condição de suportar as solicitações de carga de tráfego a elas aplicadas, visto que sua qualidade estrutural, obtida pela técnica mencionada, apresentou-se em boas condições, em função dos pavimentos terem apresentado deflexões máximas inferiores às admissíveis, bem como raios de curvatura muito superiores a 100 m. Como complemento à análise estrutural, realizou-se análise das condições funcionais do revestimento com relação à aderência pneu-pavimento, a qual apresentou valores para microtextura e macrotextura bem fora dos intervalos recomendados pelas normas.
19

Bookkeeping Procedures for the Application of the Concept of Pre-Allocation of Total Float

Ambani, Nikhil 03 December 2004 (has links)
With the increasing complexity in construction projects, monitoring project schedule and managing projects effectively is becoming increasingly important. Most projects being deadline oriented, timely completion becomes a must. Like every industry, the construction industry too lays a lot of emphasis on timely completion which makes it necessary to monitor the project schedule very closely. A schedule overrun is never predicted at the start of the project but during the course of the project, even the slightest change can result in delays. As per the current scheduling practices, float is considered free. It is an expiring resource and hence the party to the use the float first owns the float. The concept endorsed by the court for analyzing delay claims is the proximate cause concept. As per this concept, the party which is the immediate cause to a particular delay is held responsible for that delay irrespective of what has happened before in the project. Due the ambiguous nature of its interpretation, the present concept on float management has now become one the primary reasons for disputes amongst the participating parties. Parties in contract are always trying to appropriate float to suit their interests. This is why total float management has gained this level of importance in today's industry. To handle this issue of total float management more efficiently, Dr. Prateapusanond (2003) proposes a new concept of total float management as an effort towards a more fair and equitable system. This concept respects the dynamic nature of construction projects and recognizes float to be an asset for both parties. The new concept proposes to allocate float in the ratio 50:50 between the parties at the start of the project. This pre-allocated float owned by each party is called the Allowable Total Float (ATF). The implementation of this concept ensures that the parties are now aware that consumption of float in a way that it affects critical activities will expose them potential damages. This concept is an effort towards a more fair and equitable system for total float management. It appears impressive on paper but its practicality and applicability remains a major concern. This research is aimed at testing the practicality of the proposed concept of pre-allocation of total float. It introduces bookkeeping procedures that will facilitate the application of the concept of Pre-allocation of total float. These procedures have been developed and tested on certain case studies to make sure that they are robust. Once their ability to handle scheduling issues is determined, the bookkeeping procedure along with the concept of pre-allocation of total float is applied to a real construction project. This research presents an in depth analysis of the nature of the proposed concept of pre-allocation of total float, the scheduling issues which this concept does not address to, and certain assumptions which could be used in conjunction with the present concept to make it robust in nature. / Master of Science
20

Litteraturplaceringens möjligheter : En studie om litteraturens placering i förskolans miljö / The Possibilities of the Placement of the Literature : A study about the placement of the literature in the preschool environment

Matilde, Lindh January 2017 (has links)
Syftet med denna studie är att undersöka hur tillåtande, tillgänglig och föränderlig litteraturen är i förskolans miljö. Undersökningen har genomförts genom intervjuer med förskollärare, samt genom observation och dokumentation av litteraturens placering med hjälp av foton. Resultatet visar att förskolorna har litteraturen nära platsen för vila, för att litteraturen ska vara tillgänglig och nära till hands när barnen och pedagogerna ska läsa. Litteraturen är i barnens höjd vilket gör att de kan plocka till sig litteraturen när de önskar. Utöver litteraturen i samband med platsen för vila, har några avdelningar fördelat litteratur på resten av avdelningen. Två av avdelningarna har litteratur i näst intill alla rum för att den ska vara tillgänglig för barnen överallt, även i leken. På några förskolor är litteraturens miljö ständigt i förändring, medan de på andra nästan aldrig förändrar miljön. Förskollärarna är medvetna om litteraturens och miljöns betydelse för barnen, dock speglas detta inte alltid i verksamheten. Förskollärarna är alltså medvetna om syftet till litteraturplaceringen i olika grad. / The main purpose with this survey is to review how variable, available and allowable the literature is in the preschool environment. When having interviews with preschool teachers and through observation and documentation of the placement of the literature by photos, the answers to the main questions have been answered. The result showed that the preschools have literature next to the place for rest because it´s supposed to be close while reading for the children. The literature is in available height for the children so they can reach the literature. Except the literature by the resting place some of the preschool teachers have placed the literature in every room so it is available everywhere in the preschool, even in the children’s play environment. The preschool teachers were aware of the meaning of the surrounding and the literature for the children, unfortunately this didn´t always reflect in the preschool environment. The preschool teachers were aware of the purpose and the placement of the literature in different degrees.

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