• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2665
  • 917
  • 537
  • 301
  • 211
  • 189
  • 141
  • 63
  • 58
  • 48
  • 28
  • 26
  • 17
  • 17
  • 15
  • Tagged with
  • 6158
  • 789
  • 631
  • 551
  • 534
  • 527
  • 496
  • 478
  • 412
  • 365
  • 354
  • 341
  • 332
  • 318
  • 283
  • 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.
121

VLIV PORÁŽKOVÉ HMOTNOSTI A POHLAVÍ NA JATEČNOU HODNOTU PRASAT / The influence of slaughter weight and sex on carcass of pigs.

VONDRUŠKA, Miroslav January 2012 (has links)
The aim of this thesis was to obtain information on the genotype and sex influence on carcass characteristics of pigs of the following final hybrids combinations: (CL x CLW) x CLW ? sire line, (CL x CLW) x (CLW ? sire line x Pn), (CL x CLW) x (D x Pn) and (CL x CLW) x (CLW ? sire line x D) with a balanced sex ratio (barrows: gilts). An influence of the genotype on the lean meat content has been proven, while the (CL x CLW) x (D x Pn) combination reached the highest values, with an average of 57.95 %. A statistical significance of differences was also found between the sexes, when gilts reached 58.06 % average lean meat content, compared to the barrows 54.70 % average lean meat content (3.36 % difference). The back fat thickness showed a high statistical significance in terms of genotype, the lowest back fat thickness was measured in the (CL x CLW) x (D x Pn) combination with value of 21.69 mm. Barrows reached higher values, the average height of gilts was 22.03 mm, 25.25 mm in barrows. In the loin eye area indicator, the genotype influence has not been proven. For gilts, the mean value of 5228 mm2, in barrows value of 4707 mm2. Content of main meat parts, or more precisely hams, presented statistically significant differences in terms of genotype. The (CL x CLW) x (D x Pn) combination reached the highest values, with content of 53.23 %, 21.9 % respectively. A significant statistical difference was determined also between sexes, with an average main meat parts of gilts and barrows 51.32 % and 48.45 %, respectively; in the case of ham 21.07 % and 19.98 %. The slaughter weight in relation to the lean meat content showed a very good value in the mass range less than 100 kg (57.84 %), but the muscle proportion 57.16 % has been positive even in the mass range 100 ? 109.9 kg.
122

Analysis of a Hybrid Energy Storage System and Electri ed Turbocharger in a Performance Vehicle

Stiene, Tyler January 2017 (has links)
This research investigates the effects of both a Hybrid Energy Storage System and an Electrified Turbocharger in a consumer performance vehicle. This research also attempts to support the development of a prototype vehicle containing a Hybrid Energy Storage System currently being developed at McMaster University. Using a custom simulation tool developed in Matlab Simulink, Simulink models of each of the technologies were developed to predict the behavior of these subsystems across multiple physical domains. Control modeling, optimization and testing was completed for both systems. In addition, controls modeling for the Hybrid Energy Storage System was integrated with the development effort for a prototype vehicle considering the specifics of real world components. To assess the impact of these technologies on a performance vehicle platform, the simulation tool tested each technology using multiple vehicle variations. Three vehicle variants were developed, representing: a conventional performance hybrid design, a hybrid vehicle containing an electrified turbocharger, and a vehicle containing a Hybrid Energy Storage System. Electrical system peak output power was the vehicle specification held constant between each vehicle variant. Each vehicle variant was simulated against a number of traditional drive cycles representing everyday driving scenarios in an attempt to compare fuel economy while identifying each technologies individual impact on the vehicles performance. Finally, each vehicle variant was simulated using a custom performance drive cycle in a virtual race. Both technologies as assessed and in comparison to a larger battery variant, did not result in improved fuel economies during conventional vehicle driving. Both the Hybrid Energy Storage System and electrified turbocharger demonstrated improved vehicle performance in particular scenarios. / Thesis / Master of Applied Science (MASc) / Electrified vehicles have not typically been viewed as performance vehicles. A recent trend has seen a growing number of manufacturers turn to hybrid and electric powertrains to produce high performing vehicles. However, a performance vehicle's electrical power is conventionally limited by the size and power of its battery, adding weight and cost. Two technologies offer the ability to increase the power of these electrified components without the need for a large battery. First, Hybrid Energy Storage System combines ultra-capacitors and batteries to increase the power density of the system. Second, an Electrified Turbocharger improves the turbo lag of a turbocharged engine and also recovers waste heat energy from the exhaust gases which is then used to propel the vehicle. This research identifies and demonstrates the potential impact these two technologies have when included in an American Muscle Car.
123

A Theoretical Model for Life Cycle Inventory Analysis using a Disaggregated Hybrid Methodology

Spivak, Alexander January 2011 (has links)
No description available.
124

Modeling, Control and Prototyping of Alternative Energy Storage Systems for Hybrid Vehicles

Samuel Durair Raj, Kingsly Jebakumar 19 June 2012 (has links)
No description available.
125

Design, Implementation, and Testing of a High-Power Electrified Powertrain for an American Muscle Car

Lau, Robert January 2017 (has links)
This thesis outlines the design and implementation process of an electrified powertrain for use in an American muscle car. Designed as McMaster University's entrant to the EcoCAR 3 Advanced Vehicle Technology Competition (AVTC), an electrified powertrain was developed to provide a Chevrolet Camaro with the performance expected by the American muscle car market while maintaining ever increasing fuel economy regulations. A background of current trends in vehicle electrification, including the prominent market segments experiencing these trends, will be explored along with the history of the classic and modern American muscle car's technical specifications. Following an investigation into existing vehicle electrification trends, the selected hybrid architecture will be discussed. The process of converting a conventional combustion powertrain into a series-parallel hybrid electric powertrain will be explored from the component-level through to full system design. Following a review of the design process for the powertrain, a high-level testing plan will be proposed using a number of test cells available within the facility. This plan will begin at the component-level exploring specific areas of potential complication and move up to complete system-level testing of powertrain functionality. / Thesis / Master of Applied Science (MASc) / Until recently, hybrid electric vehicles have tended to be available in a fairly limited market segment with few offerings for performance-oriented vehicle customers. The introduction of high performance hybrid vehicles suggests that this trend is likely to change. Increasingly more stringent fuel economy and emissions standards means that performance vehicle segments such as American muscle cars must adopt new technologies to retain their performance characteristics. Hybrid powertrains are one solution to providing and improving on the iconic performance of American muscle while meeting future regulatory changes. The addition of a number of electrified components to a gasoline powertrain can assist in achieving desired performance while reducing fuel economy. This thesis investigates the detailed design process adopted to make these modifications while maintaining the functionality expected by muscle car owners. After the design and assembly of the hybrid muscle car powertrain, a specific testing plan was laid out to ensure that the system is capable of sustaining the expected power output. This design and testing process can help introduce new hybrid vehicles to the market which are capable of meeting both the upcoming fuel economy regulations as well as the ongoing performance expectations of the muscle car market.
126

Initiation and Termination of a Hybrid Atom Transfer Radical Polymerization System / Initiation and Termination of a Hybrid ATRP System

Machado, Mark 06 1900 (has links)
Atom transfer radical polymerization (ATRP) is a controlled/living polymerization process used to synthesize polymers with controlled molecular weight and narrow polymer distributions. Control of these key parameters allows for the fabrication of well-defined macromolecular structures, a necessary tool for the synthesis of advanced materials. Since its discovery in 1995, ATRP has received considerable interest and widespread adoption from the academic community. Unfortunately, it faces several complex challenges which have hindered its full scale commercialization, mainly its high catalyst loadings to obtain fast reaction kinetics. One of the premises of this research project was to augment the slow reaction rates of ATRP while using extremely low catalyst concentrations. A hybrid ATRP system was employed which encompassed the fast reaction kinetics associated with conventional free radical processes, with the attractive control features of ATRP. When high free radical initiator concentrations in the range of 0.1 M to 0.2 M were used in concert with ATRP, fast reaction rates were realized, while maintaining a polymerization with living characteristics. Conversions of 81% (0.117M) and 91% (0.234M) were achieved within 2 hours as compared to typical ATRPs where achieving such conversions would take up to 24 hours. For those same free radical initiator loadings (0.117M and 0.234M) the reaction demonstrated living characteristics with molecular weight growing in a linear fashion with respect to increasing monomer conversion. Despite the high free radical initiator concentration, the polymer distribution remained relatively narrow, not exceeding a polydispersity of 1.30. Chain extension experiments from a synthesized macroinitiator were successful which demonstrated the living characteristics of the hybrid ATRP process. The aforementioned polymerizations were conducted with various copper concentrations. Catalyst concentrations as low as 16 ppm (0.234mM) were found to be effective, i.e. one catalyst mediated the growth of over 100 polymer chains, and thus saving post polymerization purification. Moreover, the expensive ligand cost could be cut dramatically through a nearly 100 time reduction in the ligand concentration for these polymerizations. A hybrid ATRP system was used as a unique method to determine termination rate coefficients of MMA at 70°C as a function of both conversion and chain length. A three dimensional composite map was developed to elucidate the coupling effects of both conversion and chain length on the termination rate coefficient over a total range of data which can be used for modelling systems of this nature. / Thesis / Master of Applied Science (MASc)
127

On the Concept of the Reconfigurable Multi-Source Inverter for Electrified Vehicle Powertrains with a Hybrid Energy Storage System

Wood, Megan January 2020 (has links)
This thesis focuses on the concept, design, and simulation of the Reconfigurable Multi-Source Inverter for EV applications and its effectiveness when combined with a HESS. The current trends in the automotive market, including different vehicle types, and the adoption of electrified vehicles by the public are discussed. The benefits and logistics of different vehicle architectures are analyzed and compared. Hybrid vehicles will be essential in helping transition society from conventional internal combustion engine vehicles to purely electric vehicles. The individual components of these electrified vehicles are reviewed, and common topologies are discussed with the benefits of each system compared. The batteries required for these electric vehicles are costly and require many individual cells in order to operate efficiently. Many hybrids vehicles make use of expensive power electronics, such as DC/DC converters to help boost the operating voltage of the battery pack without adding additional cells. A Reconfigurable Multi-Source Inverter in introduced and its switching structure is explained in depth. Its’ ability to make use of multiple DC sources to create four different voltage levels is outlined and possible modulation techniques are presented. This thesis aims to introduce a novel Reconfigurable Multi-Source Inverter using a Space Vector Pulse Width Modulation (SVPWM) scheme and is further investigated through simulations and with plans for experimental validation on an R-L load. / Thesis / Master of Applied Science (MASc) / One of the main factors affecting the cost of electrified vehicles is the expense of building a high voltage battery pack. Motor’s used in electric vehicle applications typically operate at higher voltages and therefore require large battery pack or costly power electronics to step the voltage of the pack up to a suitable operating level. A Reconfigurable Multi-Source Inverter uses a combination of two sources to create different voltage levels. This novel inverter can be used to maximize the voltage of smaller packs to help reduce the overall cost of vehicle electrification.
128

Exploring Educational Technology in Hybrid Learning Environments: A Study on Usage, Support, and Challenges in a Swedish University / Utforska Utbildningsteknik i Hybrida Inlärningsmiljöer:En Studie om Användning, Stöd och Utmaningar, vid ett Svenskt Universitet

Palan, Sona January 2024 (has links)
To use technology creatively in classroom the instructor needs to have knowledge and skills to use digital technology. Teacher education program including training and workshop in using education technology by university is essential, to improve digital skills of a teacher, which helps to share knowledge, use tools that build collaboration and be a guide for students. Technology changes rapidly where newer education technology replaces the older ones. So, a teacher faces challenges in using technology and need support in using it better. Hence it is important for teachers to update their skills in using technology. As hybrid learning environment became common after pandemic situation, teachers’ preference changed from classroom teaching to a mix of online and classroom forms of teaching. This research is about studying the use of, difficulties and support needed in using education technology in hybrid environment in a Swedish university. The instrument of data collection in this study is a questionnaire sent to the respondents via email. The research findings show that the teachers in a Swedish university, teaching in hybrid learning environment have good digital skills for teaching. However, the results also show the problems faced, support needed to improve digital skills and preference to teach in hybrid environment over online only or classroom only environment. The aim of this study is to investigate from constructivist approach a) what education technology does a teacher use for teaching in hybrid learning environment in a Swedish university b) what support does the teacher need for teaching in hybrid learning environment and c) what are the issues faced by teachers in using education technology in hybrid learning environment. This research shows what education technology is used by teachers for teaching in hybrid teaching and learning environment in a Swedish university, their skills in using technology, what support is needed and what problems are faced in using technology for teaching. The findings of the study conclude that while educational technology offers significant benefits for hybrid teaching, ongoing support and addressing technical challenges are crucial for maximizing its effectiveness.
129

Modeling rate of planting, date of planting and hybrid maturity effects on yield of grain sorghum (Sorghum bicolor, (L.) Moench)

Baker, Daniel Myron January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
130

INTERKULTURELL BILDPEDAGOGIK FÖR SVERIGE I TIDEN : ämnesdidaktik i ett mångkulturellt klassrum

Leib, Linda January 2015 (has links)
Sverige har sedan slutet av 1960-talet gått mot en allt mer internationaliserad kultur som påverkats både av inre och yttre förändringar. Denna studie utgår ifrån den svenska skolans monokulturella praktik och söker ge alternativ till majoritetsnormen för att inkludera alla elever. Samma tendens till konservering återfinns i konstvärlden och bildpedagogiken vilket blir synligt då den västerländska konstkanon undersöks. I denna studie ställs frågor om hur bildläraren kan möta det allt mer heterogena och mångkulturella klassrummet och hur en anpassning efter elevunderlaget kan avspeglas i lektionsinnehållet. Studien tar också upp frågor om vilka etiska, didaktiska och kunskapsmässiga resurser som kan utvecklas med en inkluderande bildpedagogik. Det har i Sverige forskats och skrivits mycket kring interkulturell pedagogik, men obefintligt då det kommer till det bildpedagogiska fältet. Denna studie har skrivits med ambitionen att bidra med konkreta idéer om hur interkulturell bildpedagogik kan ta sig i uttryck, med en tydlig förankring till en undervisningspraktik. Studien inleds med teorier som ligger till grund för interkulturell bildpedagogik, formerande forskning från USA, Kanada och England, dessa exemplifieras sedan konkret genom en presentation av ett konsthistorieprojekt som bedrevs i år 9 på Bredbyskolan i Rinkeby 2013. Dokumentation av planering och genomförande av projektet redovisas, materialet har bearbetats efter fallstudien som metod. Syftet var att skapa förutsättningar för att använda både elevernas och föräldrarnas egna erfarenheter som resurs. Genom att presentera elevernas alster och deras tankar bakom blir det synligt att projektet möjliggjort inkludering. Studien visar på hur man medvetet kan arbeta för att eleverna blir inkluderade i lektionsinnehållet.

Page generated in 0.0481 seconds