Global ETD Search

1	Laboratory, semi-pilot and room scale control of H2S emission from swine barns using nitrite and molybdate Moreno, Lyman Denis Ordiz 15 December 2009 Emission of odorous and gaseous compounds such as hydrogen sulphide (H2S) from livestock facilities can be a major impediment to its daily operations and potential expansion. Occupational and environmental concerns require the control of H2S emissions. A treatment approach used in the oil industry in which nitrite and/or molybdate are used as metabolic inhibitors to control the production of H2S in oil reservoirs was shown to be effective in controlling H2S emissions from swine manure.<p> The addition of nitrite and molybdate to swine manure was investigated in closed laboratory scale systems and then evaluated in semi-pilot scale open systems and in specifically designed chambers aiming to simulate an actual swine barn. The effect of manure age (extent of storage) on H2S emissions and the levels of nitrite and molybdate required for effective control of these emissions were assessed. Laboratory scale tests showed that emission of H2S was dependent on manure age. Fresh manure emitted the highest level of H2S and the level of emission decreased as manure age (1-6 months) increased. With fresh 1, 3, and 6-month old manures average H2S concentration in the headspace gas of the closed systems were 4856b460, 3431b208, 1037b98 ppm, and non-detectable (<0.4 ppm), respectively. This translated to lower levels of nitrite or molybdate required to control H2S emission with increase in manure age. When compared to molybdate, the addition of nitrite initially led to lower levels of H2S but its effect was only temporary and not as persistent as molybdate. In the semi-pilot and room scale tests H2S levels emitted from untreated fresh manure (831¡Ó26 ppm and 88.4 ppm, respectively), were significantly lower than those observed in the laboratory system (4856¡Ó460 ppm). Moreover, the levels of molybdate required to control the emission of H2S were much lower in both the semi-pilot system and in the room scale chamber than in the closed system (0.1-0.25 mM as opposed to 2 mM).<p> Small scale land application of manure treated with 0.1 mM molybdate did not raise the level of molybdenum in the soil that could cause potential toxicity to plants and animals. No major differences in the nutrient properties of the soils exposed to the treated and untreated manure were observed. Finally, a preliminary feasibility study of this treatment approach showed that the cost associated with this control approach was less than 1% of the total production cost. H2S swine manure nitrite molybdate emission control room scale test
2	Laboratory, semi-pilot and room scale control of H2S emission from swine barns using nitrite and molybdate Moreno, Lyman Denis Ordiz 15 December 2009 (has links) Emission of odorous and gaseous compounds such as hydrogen sulphide (H2S) from livestock facilities can be a major impediment to its daily operations and potential expansion. Occupational and environmental concerns require the control of H2S emissions. A treatment approach used in the oil industry in which nitrite and/or molybdate are used as metabolic inhibitors to control the production of H2S in oil reservoirs was shown to be effective in controlling H2S emissions from swine manure.<p> The addition of nitrite and molybdate to swine manure was investigated in closed laboratory scale systems and then evaluated in semi-pilot scale open systems and in specifically designed chambers aiming to simulate an actual swine barn. The effect of manure age (extent of storage) on H2S emissions and the levels of nitrite and molybdate required for effective control of these emissions were assessed. Laboratory scale tests showed that emission of H2S was dependent on manure age. Fresh manure emitted the highest level of H2S and the level of emission decreased as manure age (1-6 months) increased. With fresh 1, 3, and 6-month old manures average H2S concentration in the headspace gas of the closed systems were 4856b460, 3431b208, 1037b98 ppm, and non-detectable (<0.4 ppm), respectively. This translated to lower levels of nitrite or molybdate required to control H2S emission with increase in manure age. When compared to molybdate, the addition of nitrite initially led to lower levels of H2S but its effect was only temporary and not as persistent as molybdate. In the semi-pilot and room scale tests H2S levels emitted from untreated fresh manure (831¡Ó26 ppm and 88.4 ppm, respectively), were significantly lower than those observed in the laboratory system (4856¡Ó460 ppm). Moreover, the levels of molybdate required to control the emission of H2S were much lower in both the semi-pilot system and in the room scale chamber than in the closed system (0.1-0.25 mM as opposed to 2 mM).<p> Small scale land application of manure treated with 0.1 mM molybdate did not raise the level of molybdenum in the soil that could cause potential toxicity to plants and animals. No major differences in the nutrient properties of the soils exposed to the treated and untreated manure were observed. Finally, a preliminary feasibility study of this treatment approach showed that the cost associated with this control approach was less than 1% of the total production cost. H2S swine manure nitrite molybdate emission control room scale test
3	Efektivní využití omezeného herního prostoru / Effective Use of Limited Game Space Brestič, Tomáš January 2018 (has links) Current generation of consumer electronics products for virtual reality (VR) allows to track user motion in physical play area which can be converted into a corresponding change of their position in a virtual environment. There are, however, some potential pitfalls with using this approach as the main method of user motion in the virtual space. Therefore, vast majority of contemporary applications is based on different methods that do not take advantage of the available play area and the possibilities of the input devices in their entirity. The main goal of this thesis is to propose and demonstrate a feasible way of implementation allowing the use of available physical space and to try to evaluate whether basing the user motion in an application on the described approach can result in an increase of user interest, attract more users and offer them better experience, and whether it therefore can be profitable in spite of all the related disadvantages.
4	ManiLoco: A Locomotion Method to Aid Concurrent Object Manipulation in Virtual Reality Dayu Wan (13104111) 15 July 2022 (has links) <p>In Virtual Reality (VR), users often need to explore a large virtual space within a limited physical space. However, as one of the most popular and commonly-used methods for such room-scale problems, teleport always relies on hand-based controllers. In applications that require consistent hand interaction, such teleport methods may conflict with the users' hand operation, and make them uncomfortable, thus affecting their experience. </p> <p>To alleviate these limitations, this research designs and implements a new interactive object-based VR locomotion method, ManiLoco, as an eye- and foot-based low-cost method. This research also evaluates ManiLoco and compares it with state-of-the-art Point & Teleport and Gaze Teleport methods in a within-subject experiment with 14 participants.</p> <p>The results confirm the viability of the method and its possibility in such applications. ManiLoco makes the users feel much more comfortable with their hands and focus more on the hand interaction in the application while maintaining efficiency and presence. Further, the users' trajectory maps indicate that ManiLoco, despite the introduction of walking, can be applicable to room-scale tracking space. Finally, as a locomotion method only relied on VR head-mounted display (HMD) and software detection, ManiLoco can be easily applied to any VR applications as a plugin.</p> Virtual and mixed reality Virtual Reality Locomotion Object Manipulation Room-Scale VR
5	Virtual Reality Locomotion : Four Evaluated Locomotion Methods / Rörelse inom Virtuell Verklighet : Utvärdering av Fyra Rörelsemetoder Karlsson, Rasmus, Sveninge, Alvar January 2017 (has links) Virtual Reality consumer hardware is now available for the masses through the HTC Vive, Oculus Rift and PlayStation VR. Locomotion or virtual travel inside immersive experiences is an area which is yet to be fully solved due to space constraints, problems with retaining immersion and potential sickness. This thesis had the goal of evaluating user preferences for four locomotion methods in Virtual Reality with a first generation HTC Vive through the gaming platform Steam. The theoretical framework provides an elementary understanding of the field of Virtual Reality and how humans interact and get affected by locomotion in that context. To contextualize the experience of evaluating the locomotion systems the Hedonic-Motivation System Adoption Model is used as it covers intrinsic motivation which is common in video games, social networking and virtual worlds. An extensive process for games selection has been performed which has resulted in four locomotion methods with four games per method. Sixteen participants got to test one locomotion method each where their gameplay got recorded for later observation. After each game session answers were provided by the participants based on surveys and after completion of all games a questionnaire gauged their sickness level. The conclusion proved inconclusive. While the results without interpretation showed the locomotion method Artificial as the overall winner a range of potential problems were found with the study in general. Some problems included observations which did not provide the expected results, introducing doubt into either how the study was conducted or the reliability of certain users. A larger sampler size along with a better study procedure could possibly have provided a more conclusive answer. VR Virtual Reality Locomotion HTC Vive Steam SteamVR Games Room-Scale Information Systems, Social aspects
6	Implementation and Analysis of Co-Located Virtual Reality for Scientific Data Visualization Jordan M McGraw (8803076) 07 May 2020 (has links) <div>Advancements in virtual reality (VR) technologies have led to overwhelming critique and acclaim in recent years. Academic researchers have already begun to take advantage of these immersive technologies across all manner of settings. Using immersive technologies, educators are able to more easily interpret complex information with students and colleagues. Despite the advantages these technologies bring, some drawbacks still remain. One particular drawback is the difficulty of engaging in immersive environments with others in a shared physical space (i.e., with a shared virtual environment). A common strategy for improving collaborative data exploration has been to use technological substitutions to make distant users feel they are collaborating in the same space. This research, however, is focused on how virtual reality can be used to build upon real-world interactions which take place in the same physical space (i.e., collaborative, co-located, multi-user virtual reality).</div><div><br></div><div>In this study we address two primary dimensions of collaborative data visualization and analysis as follows: [1] we detail the implementation of a novel co-located VR hardware and software system, [2] we conduct a formal user experience study of the novel system using the NASA Task Load Index (Hart, 1986) and introduce the Modified User Experience Inventory, a new user study inventory based upon the Unified User Experience Inventory, (Tcha-Tokey, Christmann, Loup-Escande, Richir, 2016) to empirically observe the dependent measures of Workload, Presence, Engagement, Consequence, and Immersion. A total of 77 participants volunteered to join a demonstration of this technology at Purdue University. In groups ranging from two to four, participants shared a co-located virtual environment built to visualize point cloud measurements of exploded supernovae. This study is not experimental but observational. We found there to be moderately high levels of user experience and moderate levels of workload demand in our results. We describe the implementation of the software platform and present user reactions to the technology that was created. These are described in detail within this manuscript.</div> Software Engineering Computer Software Computer Graphics Simulation and Modelling Virtual Reality and Related Simulation Mobile Technologies Networking and Communications Computer-Human Interaction Collaborative Virtual Reality Virtual Reality Collaborative Virtual Reality Networking Networked VR Mulitplayer Multiplayer VR Data Visualization Data Exploration Head Mounted Display Cyberspace Augmented Reality Emerging Technologies Consumer Devices Virtual Environment Virtual Aesthetics Collaborative VR Simulation Training Simulation and Training Colocated Colocated Virtual Environment Immersive Media Immersive Technology Collaborative Tools Educational Virtual Environment Point Cloud Representations Isosurface Representations Mesh Smoothng Supernova Supernovae Supernova Remnant Modeling Astronomy and Astrophysics Cassiopeia N132D E0102 Crab Nebula CAVE CAVE Theater Mobile VR Virtual Classrooms STEM Workload Workload Assessment Tool Presence Engagement Immersion Experience Consequence Simulator sickness Simulator Sickness Questionnaire NASA TLX NASA Task Load Index Unified User Experience Quesionnaire Modified User Experience Questionnaire Oculus Oculus Go Oculus Quest Novel Solutions Optitrack Motive Motion Capture Mocap User Experience Unity3D Game Engine Lidgren Room Scale VR Hall Scale VR Co-location Colocation Virtual Training Collaborative Virtual Environments Shared Virtual Environments Collaboration Whiteboard Mobile Virtual Reality VR HMD LAN UX CSCL UXQ TLX AR VE CVE 3D UI EVE

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