• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 183
  • 60
  • 31
  • 31
  • 17
  • 17
  • 8
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 438
  • 82
  • 68
  • 61
  • 33
  • 33
  • 31
  • 31
  • 29
  • 27
  • 26
  • 26
  • 25
  • 24
  • 24
  • 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.
251

Survey of Barbell Trajectory and Kinematics of the Snatch Lift from the 2015 World and 2017 Pan-American Weightlifting Championships

Cunanan, Aaron, Hornsby, W. G., South, Mark A., Ushakova, Kristina P., Mizuguchi, Satoshi, Sato, Kimitake, Pierce, Kyle C., Stone, Michael H. 20 August 2020 (has links)
Analysis of elite performances is important to elucidate the characteristics of effective weightlifting technique contributing to the highest level of achievement. The general technique of the weightlifting movements is well established. However, it is also apparent that weightlifting technique can differ based on athlete characteristics. Thus, existing technical models may not accurately reflect current technique of top performers or be applied generically to athletes of different skill, size, sex, or ability. Therefore, the purpose of this descriptive study was to update the scientific knowledge of snatch technique of top international weightlifters. This study used video analysis to determine barbell trajectory and kinematics of 319 successful snatch attempts from two major international competitions. Relative frequencies of barbell trajectory types differed based on competition, sex, category, and ranking. No statistical differences were observed among the top-three performers for either sex for most kinematic variables, and there were no overall discernible patterns of effect size differences for individual or clusters of kinematic variables. The results of this study indicate that weightlifting success can be achieved with a variety of technique profiles.
252

Temporal Dynamics In Microplastics Within An Indoor Environment: Insights From A Novel Tape-Lifting Method / Mikroplasters temporala dynamik i en inomhusmiljö: insikter från en ny tejplyftsmetod

Wiklund, Matilda January 2022 (has links)
Microplastics (MPs) constitute a risk to both human and environmental health. It is vital to identify sources and pathways to take the necessary action and limit the number of MPs in our environments. However, we currently have a limited understanding regarding MPs' variation with time in urban environments in an indoor setting. This knowledge gap is partly due to the absence of standard sampling procedures, and there is a need to develop reliable sampling techniques. This study evaluates the effectivity of a novel tape-lifting method developed for sampling MPs from various urban surfaces and applies this technique to measure weekly trends in artificial polymer deposition within an indoor environment at Umeå University. Two stone floor surfaces were sampled repeatedly on eight occasions over three weeks. Recovered MPs were identified in a microscope and categorized after shape: fibers or fragments. My developed tape-lifting method showed high MP recoveries (on average 100 ±4%) for the majority of the tested indoor surfaces (floors and tables). However, the method proved less functional for outdoor substrates (asphalt), where the recovery was significantly lower (on average, 48% ± 17). In my monitoring of MPs, I found that the deposition rate of fibers did not significantly differ between the two sampling sites or change over the three weeks. In contrast, MPs of fragment-type varied both between sampling sites and as a function of time. Here, the MP deposition rate was, on average, nearly two times higher at one of the sites, indicating substantial spatial variation. Regarding temporal variation, fragmented MPs showed an overall decrease in the number of deposited fragments over the three-week period. Interestingly the lack of variation in fibrous MPs indicates a dominating input source of fibers that is both homogenous for the room and static with time. In contrast, a specific source that is also time-sensitive appears to influence the dispersal pattern of fragmented MPs. My findings highlight the need to consider the temporal dimension of MP contamination and for research focusing on the relationship between fragmented MPs and their sources in indoor environments.
253

The effects of a combined weight training and running program on body composition in college males

Hesslink, Robert L., Jr. 01 January 1983 (has links)
The present study attempted to investigate whether a combined weight and endurance training program can elicit more favorable changes in body composition than either method of training alone. Body composition parameters (absolute fat and fat-free weight) were evaluated using circumference measurements, skinfolds and hydrostatic weighing. Cardiorespiratory fitness was evaluated via a modified Harvard step-test. All tests were administered before and after 10 weeks of training. Exercises were performed 3 days/week for 40 minutes/day. Male volunteers (n=21) were randomly assigned to one of three treatment groups (weight training only, endurance running only, combined weight training and endurance running).
254

Manipulační vozík pro manipulaci s velkonábalem o nosnosti 1500 kg / Handling truck for manipulation of cone with product, load capacity: 1500 kg

Gavenda, Jiří January 2013 (has links)
The thesis discusses a constructional project of a simple handling truck for an easy taking out of a cone with the product of load capacity of 1500 kg from the line winder and removing it from the line. The aim is to propose a simple construction of the truck including a suggestion of a possible solution of the lift. It deals with its design including processing of important strength construction calculations and lifting parts. There is also a significant part of the work which includes the drawing documentation.
255

Designing and Developing a Lifting Device to Assist People Transfer Independently To and From a Handcycle : A product concept for people with spinal cord injury

Pedersen, Ida Marie Palmgren, Shakeeb, Mohammad January 2023 (has links)
Introduction: Handcycling is an excellent exercise for people with spinal cord injuries. However, some users experience barriers to transferring to the handcycle. The most common barriers are the height difference between the handcycle and sitting surface and dependence on others. Purpose: This thesis aims to develop an assistive technology to help users independently transfer in and out of a handcycle. Methods: The framework for the thesis is the double-diamond, guiding the designing of the products concepts. Users, professionals, and manufacturers were interviewed regarding the facilitators and barriers while transferring in and out of the handcycle and the product needs to help prevent the barriers. A content analysis was performed to find the facilitators and barriers, and a need analysis was performed to find the needs for the product. The needs were translated into target specifications to have measurable characteristics. Benchmarking was performed, and the products were evaluated in regard to the target specifications. The market segment, personas, mood board, and design brief served to inspire and inform the specifications for the product. Brainstorming and sketching were performed to generate four concepts. The participants evaluated these concepts, and the top-ranked concept was further developed. A computer-aided model was created and rendered to better illustrate the product. A guide on how to use the product was developed based on TAI 4.0, which also was used to find limitations in the transfer technique of the new product. An evaluation regarding the target specifications was also performed. Result: The final product concept allows height transfer and can be used independently. It fulfills seven out of the seventeen target specifications in the current state. However, six target specifications cannot be defined yet as they should be developed further in other iterations. Conclusion: A lifting device concept for transferring was developed. It would still need further iterations to keep improving the product before it would be able to be released for users.
256

Development of Lifting Line Theory for the FanWing Propulsion System

Kaminski, Christopher 01 January 2021 (has links)
The FanWing propulsion system is a novel propulsion system which aerodynamically behaves as a hybrid between a helicopter and a fixed wing aircraft, and if the knowledge base with regards to this novel concept can be fully explored, there could be a new class of aircraft developed. In the current research, only 2D CFD studies have been done for the FanWing, hence the 3D lift characteristics of the FanWing have been unknown thus far, at least in the theoretical domain. Therefore, it was proposed to develop a modified Prandtl's Lifting Line Theory numerical solution and a CFD solution, comparing the results of each. A new variable was introduced into the classical Lifting Line Theory solution, αi,FW, to account for the additional lift produced by the FanWing as opposed to a traditional airfoil. This variable, αi,FW, is a function of the wing angle and the velocities taken at three-quarter chord length on the FanWing. The introduction of this variable was informed by other papers which superimposed velocities when developing Lifting Line Theory for unconventional airfoil planforms. After introducing a correction factor, the numerical model aligned with the 3D CFD results where LLT assumptions were valid. For the 3D simulation, it was observed that the lift per unit span rapidly increases from quarter span to wingtip, which is different from traditional wing planforms. This study provides a valuable first step towards documenting the 3D lift characteristics of the novel FanWing propulsion system.
257

Energy saving in the process of gas pipeline overhaul

Mitrokhin, Alexey January 2014 (has links)
The problem of energy saving during overhaul of a linear part of gas trunkline is regarded in this paper. This issue has been analyzed from different perspectives. Thermodynamic analysis of gas evacuation from a string that is off operation for the overhaul to a parallel or adjacent string with the use of mobile compressor systems was made. Economical attractiveness of mobile compressor systems applications was proved. Various methods of gas trunklines linear parts overhaul have been considered. For each of the methods problems of minimization of necessary for the overhaul amount of energy consuming machines have been solved. The results can be used in the development of overhaul projects of the gas trunklines linear parts.
258

Utveckling av lyftverktyg vid monteringen av statorer i elektriska motorer / Development of lifting tools for the assembly of stators in electric motors

Svensson, Martin, Himreus, Axel January 2023 (has links)
The main purpose of this thesis is to develop an efficient and safe lifting device that can make the manufacturing process of electrical motors efficient but also make the work environment safer. The process of the product development has been following steps taught at Universities around the world. These steps go from identifying the problem and making requirements to generating concepts and developing the most suitable one. In order to learn the operators’ opinions, a survey for choosing the right concept was applied at the production line that will use the lifting tool. A choice of concepts and a lifting tool was developed based on the survey results. This development includes calculations of forces, strength of materials simulations and detailed design of the different subfunctions. The result is a developed concept consisting of a physical prototype and drawings for manufacturing.
259

Parallel Computation of the Interleaved Fast Fourier Transform with MPI

Mirza, Ameen Baig January 2008 (has links)
No description available.
260

Novel silviculture practices for non-industrial private forest landowners

Collins, Darcey Alyce 09 August 2022 (has links) (PDF)
Many landowners in the southeastern United States have invested in southern yellow pine plantations and managed them using traditional management schemes. However, non-industrial private forest landowners often have goals and challenges that make traditional management less desirable or possible. This thesis contains two projects that offer potential solutions for these landowners. The first project is a management option for landowners with small parcels that wish to manage pine plantations and proposes low-density management paired with crown lifting for the production of saw logs without commercial thinning entries. The second proposes a method for incorporating mixed-species management into already existing plantations. This increases biodiversity and could be more ecologically stable than single-species plantations. These options present opportunities for non-industrial private forest landowners who do not fit into the traditional management framework due to differences in management goals or economic constraints on management.

Page generated in 0.0442 seconds