To see the other types of publications on this topic, follow the link: Gravity system.
Dissertations / Theses on the topic 'Gravity system'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Gravity system.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Remmers, Tobias. "Gravity Control System: Realistic Balanced Poses and Animations." Thesis, University of Gävle, Department of Mathematics, Natural and Computer Sciences, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-158.
Full textAbstract:
The Gravity Control for Maya will be extraordinary
beneficial to an animator trying to create realistic
animation, by calculating the center of gravity and area
of balance. This control will provide the animator with
the ability to rotate around the center of gravity and
keep the character in a balanced pose. With that ability,
the animator can easily create accurate poses and
animation, such as mid-air flips. The system also
supports a vast number of characters with different
shapes, sizes and number of limbs.
2
Wu, Lichuan. "Introducing Surface Gravity Waves into Earth System Models." Doctoral thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-314760.
Full textAbstract:
Surface gravity waves alter the turbulence of the bottom atmosphere and the upper ocean. Accordingly, they can affect momentum flux, heat fluxes, gas exchange and atmospheric mixing. However, in most state-of-the-art Earth System Models (ESMs), surface wave influences are not fully considered or even included. Here, applying surface wave influences into ESMs is investigated from different aspects. Tuning parameterisations for including instantaneous wave influences has difficulties to capture wave influences. Increasing the horizontal resolution of models intensifies storm simulations for both atmosphere-wave coupled (considering the influence of instantaneous wave-induced stress) and stand-alone atmospheric models. However, coupled models are more sensitive to the horizontal resolution than stand-alone atmospheric models. Under high winds, wave states have a big impact on the sea spray generation. Introducing a wave-state-dependent sea spray generation function and Charnock coefficient into a wind stress parameterisation improves the model performance concerning wind speed (intensifies storms). Adding sea spray impact on heat fluxes improves the simulation results of air temperature. Adding sea spray impact both on the wind stress and heat fluxes results in better model performance on wind speed and air temperature while compared to adding only one wave influence. Swell impact on atmospheric turbulence closure schemes should be taken into account through three terms: the atmospheric mixing length scale, the swell-induced momentum flux at the surface, and the profile of swell-induced momentum flux. Introducing the swell impact on the three terms into turbulence closure schemes shows a better performance than introducing only one of the influences. Considering all surface wave impacts on the upper-ocean turbulence (wave breaking, Stokes drift interaction with the Coriolis force, Langmuir circulation, and stirring by non-breaking waves), rather than just one effect, significantly improves model performance. The non-breaking-wave-induced mixing and Langmuir circulation are the most important terms when considering the impact of waves on upper-ocean mixing. Accurate climate simulations from ESMs are very important references for social and biological systems to adapt the climate change. Comparing simulation results with measurements shows that adding surface wave influences improves model performance. Thus, an accurate description of all important wave impact processes should be correctly represented in ESMs, which are important tools to describe climate and weather. Reducing the uncertainties of simulation results from ESMs through introducing surface gravity wave influences is necessary.
3
Page, Gary L. "Exploring the weak limit of gravity at solar system scales." Fairfax, VA : George Mason University, 2009. http://hdl.handle.net/1920/4547.
Full textAbstract:
Thesis (Ph.D.)--George Mason University, 2009.Vita: p. 234. Thesis director: John F. Wallin. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computational Sciences and Informatics. Title from PDF t.p. (viewed Oct. 11, 2009). Includes bibliographical references (p. 224-233). Also issued in print.
4
Moss, Andrew M. "Analysis of a Gravity Hinge System for Wind Turbines." Cleveland State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=csu1624479290234317.
Full text
5
Cheng, Quan Jia. "A WLAN location estimation system using center of gravity as an algorithm selector." HKBU Institutional Repository, 2013. http://repository.hkbu.edu.hk/etd_ra/1513.
Full text
6
Li, Xiaopeng. "Moving base INS/GPS vector gravimetry on a land vehicle." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1195677222.
Full text
7
Hollis, Pierre G. "An improved Magnetic, Angle rate, Gravity (MARG) body tracking system." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA397552.
Full textAbstract:
Thesis (Electrical Engineer and M.S. in Electrical Engineering) Naval Postgraduate School, June 2001.Thesis advisors, Xiaoping Yun, Sherif Michael, Eric R. Bachmann. Includes bibliographical references (p. 53-54). Also Available online.
8
Trout, Alvin McKinley. "Further Study of the Gravity Loading Base Test Method." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/35025.
Full textAbstract:
Presently, the industry accepted method for determining the positive moment strength of gravity loaded standing seam metal roof systems is the "Base Test Method". The Base Test Method provides a means for determining the positive moment strength of a multiple span, multiple purlin line standing seam roof system using the results from a set of six single span, simply supported, two-purlin line experimental tests. A set of six base tests must be conducted for each combination of purlin profile, deck panel profile, clip type, and intermediate bracing configuration. The primary objective of this study is to investigate the possibility of eliminating some of the roof system parameters specifically, clip type, purlin flange width, and roof panel thickness.
This study used the results from nine series of tests. Each series consists of 11 to 14 gravity loaded base tests. The first three series were used to examine the effects of clip type on the strength of standing seam roof system. The final six series was used to examine the effects of flange width and roof panel thickness. All nine series were constructed using Z-purlin sections with flanges facing the same direction (like orientation).
Based on the results of this study, clip type, purlin flange width, and roof panel thickness all have an effect on the strength of standing seam roof systems. Although none of the roof components can be completely eliminated from the required test matrix, by using trend relationships an acceptable test protocol was developed that results in a significant reduction in the number of required base tests.
Master of Science
9
Fonte, Daniel John. "Implementing a 50x50 gravity field model in an orbit determination system." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/49587.
Full text
10
Sellers, Ryan J. "A Gravity Gradient, Momentum-Biased Attitude Control System for A CubeSat." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/974.
Full textAbstract:
ExoCube is the latest National Science Foundation (NSF) funded space weather CubeSat and is a collaboration between PolySat, Scientific Solutions Inc. (SSI), the University of Wisconsin, NASA Goddard and SRI International. The 3U will carry a mass spectrometer sensor suite, EXOS, in to low earth orbit (LEO) to measure neutral and ionized particles in the exosphere and thermosphere. Measurements of neutral and ion particles are directly impacted by the angle at which they enter EXOS and which leads to pointing requirements. A combination of a gravity gradient system with a momentum bias wheel is proposed to meet pointing requirements while reducing power requirements and overall system complexity. A MATLAB simulation of dynamic and kinematic behavior of the system in orbit is implemented to guide system design and verify that the pointing requirements will be met. The problem of achieving the required three-axis pointing is broken into four phases: detumbling, initial attitude acquisition, wheel spin-up, and attitude maintenance. Ultimately, this configuration for attitude control in a CubeSat could be applied to many future missions with the simulation serving as a design tool for CubeSat developers.
11
Rye, Maria del Carmen. "Dynamics and Control of a Tensegrity System in Low-Earth Orbit." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/77584.
Full textAbstract:
Tensegrity is the name given to a system of interconnected bars and tendons that can form a flexible self-standing structure. Its flexibility is due to the ability of the bars to move near-independent to each other, movement that can be caused by controlled tension forces in the tendons or external forces such as gravity. However, a balance of sorts must be maintained - if a tendon were to go slack, the entire structure could become unstable and collapse on itself.
This thesis looks at placing a tensegrity structure in orbit around the Earth. As a spacecraft's orbit is moved further away from the Earth, the strength of the Earth's gravity field lessens. Ideally, such a flexible structure would be placed far enough away from the Earth so that the gravity field would have too weak an impact on its individual elements to cause major distortions. However, the author recognizes that altitudes below 2,000 km, where the Earth's gravity field is still very prevalent, are the most common altitudes used by orbiting spacecraft today. The goal of this thesis is to analyze the distortions of the tensegrity structure at these lower altitudes, and also look at methods for controlling these distortions.Ph. D.
12
Hegmann, Mary Jane. "Gravity and magnetic surveys over the Santa Rita Fault System, southeastern Arizona." Thesis, The University of Arizona, 1998. http://hdl.handle.net/10150/278675.
Full textAbstract:
Gravity and magnetic surveys were performed in the northeast portion of the Santa Rita Experimental Range, in southeastern Arizona, to identify faults and gain a better understanding of the subsurface geology. A total of 234 gravity stations were established, and numerous magnetic data were collected with portable and truck-mounted proton precession magnetometers. In addition, one line of very low frequency electromagnetic data was collected together with magnetic data. Gravity anomalies are used to identify two normal faults that project northward toward a previously identified fault. The gravity data also confirm the location of a second previously interpreted normal fault. Interpretation of magnetic anomaly data indicates the presence of a higher-susceptibility sedimentary unit located beneath lower-susceptibility surficial sediments. Magnetic anomaly data identify a 1-km-wide negative anomaly east of these faults caused by an unknown source and reveal the high variability of susceptibility in the Tertiary intrusive rocks in the area.
13
Wood, Joshua. "Solutions of conformal gravity with dynamical mass generation in the solar system." Thesis, University of Canterbury. Physics and Astronomy, 2000. http://hdl.handle.net/10092/5580.
Full textAbstract:
An investigation is made into the viability of the fourth-order conformal theory of gravity with dynamical mass generation. This is done by considering the analytical behaviour of the equations of motion and using this as a guide to producing numerical solutions to these equations. A review of some criticisms of the fourth-order gravity theory is included.
Numerical solutions of the equations of motion are produced for the domain interior to the source and the exterior region within the solar system, with a variety of source conditions and under different formulations. These are analysed with consideration of reasonable physical and observational requirements, based on the well established solar system gravitational effects. The possibility of extra gravitational effects to explain anomalies in current gravitational theory is investigated. These effects include the possible anomalous acceleration of the Pioneer spacecraft, and could be extended to cover galaxy-scale phenomena such as galactic rotation curves.
Conclusions are then drawn about what formulations and parameter sets are viable for good representation of the physics. The effects of the dynamical mass generation on observed phenomena are discussed, with reference to the potential resolution of gravitational anomalies.
14
Huang, Chuen-Chane. "Biped robot with a vestibular system." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39834.
Full textAbstract:
The kinematics and dynamics of two legged or biped walking is considered. The resulting governing equations include actuator torques for a robot and muscle generated torques for a human. These torques are those necessary at each joint of a leg, including the foot, for a successful stride. The equations are developed from a consistent set variables with respect to a single inertial reference frame. This single reference frame approach has not been used by previous investigators. Control of the joint torques makes biped walking an extraordinary complex problem from a dynamics and control viewpoint. The control scheme that is developed incorporates the use of the direction of gravity as an important element in the overall control. The inclusion of gravity in biped robot walking has not previously been properly considered in other works.
A way is described to separate gravity and acceleration which are measured by an accelerometer which is on the robot. This system incorporates the use of angular motion sensing of the robot segment that contains the linear accelerometers. This system was formulated based on human motion sensing and what probably is present in the human central nervous system for processing these signals.Ph. D.
15
Han, Shin-Chan. "Efficient global gravity field determination from satellite-to-satellite tracking." Columbus, Ohio : Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1061995200.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2003.Title from first page of PDF file. Document formatted into pages; contains xvii, 198 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Christopher Jekeli, Dept. of Geodetic Science and Surveying. Includes bibliographical references (p. 192-198).
16
Smith, Robert K. "The contour-advective semi-Lagrangian hybrid algorithm approach to weather forecasting and freely propagating inertia-gravity waves in the shallow-water system." Thesis, St Andrews, 2009. http://hdl.handle.net/10023/716.
Full text
17
Tulsiani, Deepti. "A Fringe Projection System for Measurement of Condensing Fluid Films in Reduced Gravity." Digital WPI, 2006. https://digitalcommons.wpi.edu/etd-theses/5.
Full textAbstract:
The thesis describes the design of a fringe projection system to study the dynamics of condensation with potential application in a reduced gravity environment. The concept is that an optical system for imaging the condensation layer enables extraction of valuable data from the image because of the ability of the optical system to image the perturbations in the condensation films. By acquiring a sequence of images of the deformed fringe pattern, the change in the surface topology can be observed over time, giving greater understanding of condensation dynamics in reduced gravity.
18
Hatlen, Morten. "On-board, Fourier-Based Image-Analysis System for Satellite Observation of Gravity Waves." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22860.
Full textAbstract:
The main objective of this thesis is obtaining data on gravity waves from images taken by the NTNU Test Satellite (NUTS). The satellite's main payload consists of a camera intended to capture images of gravity waves in the atmosphere. A limitation of the satellite is its ability to transmit data. Two separate approaches have been investigated to limit the amount of data that needs to be sent. One is the degree of image and video compression that can be applied to a series of images before data is corrupted. The second is implementing a 3D-Fast Fourier Transform (FFT) method that obtains the relevant data in the image series directly and only sends these. The NUTS-satellite is a project still in the making with a preliminary launch date in 2014. Currently there are no comparable, usable images of the wave phenomenon captured from space. Ground based images taken with fish-eye lenses are therefore used as a basis to make emulate satellite images. These are used to test how satellite images will be influenced by compression and how the 3D-FFT can extract the data. We found the 3D-FFT able to extract wave parameters from the images, providing significant reduction in the need for transmission of data compared to sending compressed images. In addition we found that the compression-approach corrupts data before a considerable reduction in transmitted data is achieved.
19
Tulsiani, Deepti. "A fringe projection system for measurement of condensing fluid films in reduced gravity." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-010406-234259/.
Full text
20
Chandrashaker, Rajagopalan Carleton University Dissertation Engineering Civil. "Seismic analysis of gravity dam-reservoir-foundation system using an effective hybrid technique." Ottawa, 1992.
Find full text
21
Cañizales, Díaz Jorge (Jorge Luis). "Automatic design of the gravity-reducing propulsion system of the TALARIS Hopper Testbed." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76164.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, September 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 87-93).
This thesis describes a Systems Engineering tool for automatic design, presents the results of its application to the problem of designing Earth-based reduced-gravity simulators, and compares the performance of the found optimal design solutions with that of the MIT TALARIS Hopper Testbed. Earth-based reduced-gravity simulators are platforms that allow hosted vehicles to experience a dynamic environment -from a guidance, navigation, and control perspective- analog to other planetary surfaces. Simulators are used for system development and operator training purposes. Specifically, reduced-gravity simulators produce a constant vertical thrust equal to a fraction of the weight of the studied vehicle, this yielding a perceived gravity equal to the gravity of the celestial body of interest. Planetary hoppers explore planetary surfaces through hopping, i.e. low altitude and short-duration flying. Recently, these systems have gained popularity as cost-effective means for planetary exploration due to their larger operational flexibility compared to other exploration systems. The tool developed as part of this thesis eases the compilation and use of parts catalogs in the design task, includes real-time visualization of the search process, supports the output of multiple solutions that optimize conflicting goals, efficiently calculates Pareto frontiers of solutions, and can integrate external solvers and simulators seamlessly. Chapter 1 overviews the engineering challenges associated with Earth-based reduced-gravity simulators applied to planetary hoppers. Chapter 2 provides the context knowledge required for the development of the individual tasks in this thesis. Chapter 3 discusses the engineering literature covering relevant previous work. Chapter 4 describes the selected approach and the tool that has been developed for the design of the propulsion system of the simulator. Chapter 5 discusses the applicability of the approach and design tool to the case of the MIT TALARIS Hopper Testbed. Chapter 6 summarizes the results and outlines avenues for future research in this field.
by Jorge Cañizales Díaz.
S.M.
22
Mokobodi, Dineo Stephen. "Designing and developing a free fall absolute gravity measuring system using pneumatic actuators." Diss., University of Pretoria, 2005. http://hdl.handle.net/2263/66225.
Full textAbstract:
A gravimeter is an instrument that measures gravitational force Fg (N) or acceleration g (m/s-2). Absolute gravity measurements are preferred in metrology, due to the shortest traceability links to the SI base units of length and time, realising acceleration. The investigation on the suitable method of gravity measurement was performed at the National Metrology Institute of South Africa (NMISA). The free fall gravity measuring system was adopted for development. The metrological need on redefining the kilogramme standard using the watt balance, supported the decision to mandate this project. Free fall gravimeters were researched. The new concept of fully pneumatic controlled vacuum chamber was invented and manufactured. Pneumatic actuators were used on the vacuum chamber to align, launch, capture and reposition the falling test mass. Laser interferometer and high-speed digitiser with embedded accurate clock module, were used in realising displacement and time, through numerical computations. Using stabilised He-Ne Laser red with wavelength =633 nm interferometer, free-falling test mass displacements were traceable to length standard. Interference intensity signal produced from experimental free fall drops were converted to A digital voltage signal enabling processing. Post signal processing algorithms were applied to the signal to extract the displacement and time coordinates of the free-falling object, using a zero-crossing detection method in a LabView environment. The final prototype setup measured the value 9.786041 m/s2 with uncertainty of 0.0000705 m/s2 at the vacuum pressure of 0.05 Pa. It was validated and compared with the Council of Geophysics_ measured value of the site of 9.7860985 m/s2.Dissertation (MEng)--University of Pretoria, 2017.
Mechanical and Aeronautical Engineering
MEng
Unrestricted
23
Flores, Solano Francisco Xavier. "Influence of the Gravity System on the Seismic Performance of Special Steel Moment Frames." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/73143.
Full textAbstract:
This study investigates the influence of the gravity load resisting system on the collapse performance of Special Steel Moment Frames (SMFs). The influence was quantified using the FEMA P-695 methodology. The buildings used for this study were a 2-, 4- and 8-story SMFs taken from the ATC76-1 project where their collapse performance was already evaluated without the gravity system. The main work of this dissertation has been divided in two parts. The first part studies the influence of the gravity system when it is incorporated explicitly as part of the lateral resisting system. Aspects of the gravity frame that were investigated include the contribution of stiffness and strength of beam to column connections, and the location of splices in the gravity columns. Moreover, this research investigates the potential for the development of inelastic deformations in the gravity columns, and the effect of such deformations on structural response. The results show that gravity connections and gravity column's continuity profoundly affect the computed response and collapse probability. The inelastic behavior in gravity columns has a less important effect but should be included in the analysis.
The second part of the investigation looks more in depth at the role of the gravity columns on the collapse performance of SMFs. Using the 2-, 4- and 8-story SMFs, the gravity columns are incorporated using the approach where all the gravity columns are lumped into one elastic, pinned at the base and continuous element. The approach is first validated by checking different aspects such as: strength of gravity connections to induce yielding into gravity columns, difference between the explicit and lumping column approach, and required gravity column's splices to provide continuity. The stiffness of the element representing the gravity columns was varied in order to find the influence of the gravity columns. At the end of the study it was found that they have a significant influence on the collapse performance of SMFs, especially on taller structures like the 8-story model. Moreover it was concluded that an adequate stiffness of the gravity columns could be found by performing nonlinear static pushover analysis.Ph. D.
24
Supak, Kevin Robert. "Reduced gravity Rankine cycle system design and optimization study with passive vortex phase separation." Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2094.
Full textAbstract:
Liquid-metal Rankine power conversion systems (PCS) coupled with a fission reactor
remain an attractive option for space power applications because system specific power
and efficiency is very favorable for plant designs of 100 kW(e) or higher. Potential
drawbacks to the technology in a reduced gravity environment include two-phase fluid
management processes such as liquid-vapor phase separation. The most critical location
for phase separation is at the boiler exit where only vapor must be sent to the turbine
because blade erosion occurs from high velocity liquid droplets entrained by vapor flow.
Previous studies have proposed that rotary separators be used to separate the liquid and
vapor from a two phase mixture. However these devices have complex turbo machinery,
require kilowatts of power and are untested for high vapor flow conditions. The
Interphase Transport Phenomena (ITP) laboratory has developed a low-power, passive
microgravity vortex phase separator (MVS) which has already proven to be an essential
component of two-phase systems operating in low gravity environments.
This thesis presents results from flight experiments where a Rankine cycle was operated
in a reduced gravity environment for the first time by utilizing the MVS for liquid and
vapor phase separation. The MVS was able to operate under saturated conditions and
adjust to system transients as it would in the Rankine cycle by controlling the amount of
liquid and vapor within the device. A new model is developed for the MVS to predict
separation performance at high vapor flow conditions for sizing the separator at the boiler, condenser, and turbine locations within the cycle by using a volume limiting
method. This model factors in the following separator characteristics: mass, pumping
power, and available buffer volume for system transients. The study is concluded with
overall Rankine efficiency and performance changes due to adding vortex phase
separation and a schematic of the Rankine cycle with the integration of the MVS is
presented. The results from this thesis indicate the thermal to electric efficiency and
specific mass of the cycle can be improved by using the MVS to separate the two phases
instead of a rotary separator.
25
Fitzpatrick, Daniel Cash. "Efficacy of gravity-fed chlorination system for community-scale water disinfection in northern Ghana." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43887.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.Includes bibliographical references (p. 84-89).
Although chlorine is one of the lowest cost ways of providing disinfection, currently billions of people lack drinking water that has had this simple treatment. Arch Chemical's Pulsar 1 unit is an innovation in chlorine dosing in that it is a gravity-fed system which does not require electricity while providing relatively accurate dosing. The purpose of this study is to investigate the technical feasibility of the Pulsar 1 unit using high-test hypochlorite (HTH) as a viable chlorination option for community-scale drinking water disinfection in Northern Region, Ghana. In addition, this study compares the Pulsar 1 unit to the household treatment of the Kosim filter plus Aquatabs. The Kosim filter is a pot-shaped Potters for Peace-type ceramic water available in Northern Ghana, while Aquatabs are an alternate chlorine product comprised of sodium dichloroisocyanurate (NaDCC). A pilot study done in Mali in 2005 by EAU Lambda showed the Pulsar's potential to correctly dose a piped water supply with a flow rate of approximately 42 gpm (9.6 m3/hr). The present pilot study has evaluated the Pulsar system in Ghana and Cambridge, MA at flow rates of 18 gpm (4.1 m3/hr) and 9 gpm (2.0 m3/hr), respectively. This was challenging because the Pulsar was designed for swimming pool applications and thus chlorinated at levels higher than appropriate drinking water. As a result, several modifications were made to lower the chlorine concentrations from the Pulsar system into the appropriate drinking water range. Both the Pulsar 1 and Aquatabs systems were found to be technically feasible. The main two advantages of using the Pulsar system over Aquatabs are the vastly reduced operational costs (in $/m3) of disinfection treatment (about 48 times cheaper) and its ability to reach an entire community (compared to just a single household).
(cont.) However, these benefits are gained as a tradeoff for increased system complexity and higher capital costs. Overall there is no "single best option", which means site-specific circumstances should dictate the appropriate technology.
by Daniel Cash Fitzpatrick.
M.Eng.
26
Hopper, Michael W. Lepage Andres. "The John Jay College Expansion Project a study of an Alternative Gravity Load Transfer System /." [University Park, Pa.] : Pennsylvania State University, 2009. http://honors.libraries.psu.edu/theses/approved/WorldWideIndex/EHT-8/index.html.
Full text
27
Baltuch, Edmund George. "A multi tier barcode based system for the construction management of industrial gravity ventilation equipment." Thèse, Montréal : École de technologie supérieure, 2008. http://proquest.umi.com/pqdweb?did=1562129971&sid=1&Fmt=2&clientId=46962&RQT=309&VName=PQD.
Full textAbstract:
Thèse (M. Ing.) -- École de technologie supérieure, Montréal, 2008."Thesis presented to École de technologie supérieure in partial fulfillment of the requirements for the degree of master construction engineering". "by Baltuch, Edmund George" -- p. de t. CaQMUQET CaQMUQET Bibliogr : f. [174-175]. Également disponible en version électronique. CaQMUQET
28
Stoll, John C. (John Christian). "Performance analysis of a GPS interferometric attitude determination system for a gravity gradient stabilized spacecraft." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/49948.
Full text
29
Ostrý, Lubomír. "Návrh elektronického subsystému pro simulátor dopadu ve snížené gravitaci." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417785.
Full textAbstract:
The focus of this thesis is development of an electronic subsystem for reduced gravity impact simulator. The research part of this thesis firstly covers methods used for simulation of microgravity or reduced gravity and compares them. Another part of research focuses on three selected potential approaches to creating the electronic subsystem for this device. The second, practical, part of this thesis describes the design and development of the electronic subsystem. The foundation of the electronic subsystem is a control unit which has been developed on the basis of an STMicroelectronics microcontroller. Using the control unit, the electronic subsystem measures pressure, position, acceleration and force in the system. Another task of the control unit is control of a stepper motor. Integration of individual elements into the electronic subsystem is described both in terms of software and hardware. Furthermore, a graphic user interface program for PC has been developed as a means to interact with the system. In the final part of the thesis, the operation of the electronic subsystem is described and lastly, the electronic subsystem is evaluated.
30
Bedada, Tullu Besha. "Absolute geopotential height system for Ethiopia." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4726.
Full textAbstract:
This study used airborne gravity data, the 2008 Earth Gravity Model (EGM08) and Shuttle Radar Topographic Mission (SRTM) digital elevation data in a ‘Remove-Compute-Restore’ process to determine absolute vertical reference system for Ethiopia. This gives a geopotential height at any isolated field point where there is a Global Navigation Satellite System (GNSS) measurement without reference to a vertical network or a regional datum point. Previously, height was determined conventionally by connecting the desired field point physically to a nearby bench mark of a vertical network using co-located measurements of gravity and spirit levelling. With the use of precise GNSS positioning and a gravity model this method becomes obsolesce. The new approach uses the ‘Remove-Restore’ process to eliminate longer to shorter wavelengths from the measured gravity data using EGM08 and geometrical and condensed gravity models of the SRTM data. This provides small, smooth and localised residuals so that the interpolation and integration involved is reliable and the Stokes-like integral can be legitimately restricted to a spherical cap. A very fast, stable and accurate computational algorithm has been formulated by combining ‘hedgehog’ and ‘multipoint’ models in order to make tractable an unavoidably huge computational task required to remove the effects of about 1.5 billion! SRTM topographic mass elements representing Ethiopia and its immediate surroundings at 92433 point airborne gravity observations. The compute stage first uses an iterative Fast Fourier Transform (FFT) to predict residual gravity at aircraft height as a regular grid on to the surface of the ellipsoidal Earth and then it used a Fourier operation equivalent to Stokes’ integral to transform the localised gravity disturbance to residual potential. The restore process determines the geopotential number on or above the Earth’s surface where practitioners need it by restoring the potential effects of the removed masses. The accuracy of the geopotential number computed from gravity and topography was evaluated by comparing it with the one derived directly from EGM08 and precise geodetic levelling. The new model is in a good agreement across 100 km baseline with a standard deviation of 56 10−2 2 −2 × m s and 39 10−2 2 −2 × m s relative to EGM08 and levelling, respectively ( 10−2 2 −2 m s is approximately equivalent to 1mm of height). The new method provides an absolute geopotential height of a point on or above the Earth’s surface in a global sense by interpolating from geopotential models prepared as the digital grids carried in a chip for use with the GNSS receiver in the field.
31
Sridhar, Siddharth. "Spacesuit and Portable Life Support System Center of Gravity Influence on Astronaut Kinematics, Exertion and Efficiency." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1447690750.
Full text
32
Hopkins, Michael. "Critical Node Analysis for Water Distribution System Using Flow Distribution." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/722.
Full textAbstract:
The expansive nature of water distribution system makes them susceptible to threats such as natural disasters and man-made destructions. Vulnerability assessment research efforts have increased since the passing of “Bioterrorism Preparedness and Response Act” in 2002 to harden WDS. This study aimed to develop a method that locates critical nodes without hydraulic analysis of every failure scenario, applicable for any size WDS, incorporates critical infrastructure, and capable of verifying method accuracy. The Flow Distribution method is the application of the gravity model, typically used to predict traffic flows in transportation engineering, to a distribution system. Flow distribution predicts the amount of demand and population that would be affected if any node in the system were disabled by solving for the distribution of each node’s outflow. Flow Distribution is applied to the hypothetical city, Anytown, USA using the computer simulation program WaterCAD to model two different disaster scenarios. Results were verified by analyzing sixteen failure scenarios (one for each node) to measure the actual demand and population effect, which was then compared to the nodes predicted by Flow Distribution. Flow Distribution predicted the critical nodes with 70% accuracy and can still be improved with future work.
33
Loo, James. "A proposed microwave system for on-line measurement of specific gravity and moisture content of dimension lumber." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26721.
Full textAbstract:
A 10 GHz microwave bridge measurement system has been developed to automatically measure the electromagnetic field parameters transmitted through a dielectric material. These parameters are used to calculate the complex dielectric constant with the free-space transmission technique. The system is used to measure the field parameters transmitted through dimension lumber and a correlation is made with two strength determining factors of lumber: specific gravity and moisture content. Hemlock and Douglas Fir wood samples were tested and a grading technique was implemented. The system is capable of estimating the specific gravity to ±0.05 accuracy and the moisture content to ±3.0% accuracy.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
34
Sharma, Anupa. "Three Essays on the Generalized System of (Trade) Preferences." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/78619.
Full textAbstract:
The Generalized System of Preferences (GSP) is a unilateral trade liberalization program in which developed countries offer non-reciprocal tariff reductions (tariff preferences) on certain products imported from designated developing and least developed countries. GSP is considered an important tool in the World Trade Organization's approach to development. This dissertation--composed of three essays--explores whether low-income countries have achieved an increased access to high-income markets as a result of these non-reciprocal tariff preferences offered to their exports. The first essay provides an overview of the GSP program. The second essay presents an evaluation of the GSP program by considering the products and markets where low-income countries' exports are concentrated. Using a theoretically consistent gravity equation for primary and processed agri-food trade over the period 1962-2010, the results illustrate that the GSP program and modifications of it have delivered significant positive effects in developing countries' exports to developed country markets in agricultural trade but not necessarily so in non-agricultural goods. The third essay develops two theoretically founded novel indices to measure preference margins offered by high-income countries to low-income countries through tariff reduction. One index captures the restrictions bilateral tariff rates impose on market access conditions of a country as compared to the most favored nation rate, called the Exponential Trade Restrictiveness Index (ETRI). The other index captures the relative ease with which a country can access foreign markets compared to its competing suppliers, called the Exponential Relative Preferential Margin (ERPM). Then, these two bilateral indices are used to develop a model of sector-based bilateral trade to re-evaluate the Generalized System of Preferences (GSP) in terms of relative market access preferences. The results show that the GSP has increased relative market accessibility for low-income countries and in turn boosted exports from these countries by 26 to 28 percent.Ph. D.
35
Zhang, Meng. "Satellite observations and numerical simulations of jet-front gravity waves over North America and North Atlantic Ocean." Texas A&M University, 2008. http://hdl.handle.net/1969.1/85995.
Full textAbstract:
In this study, a month-long simulation of gravity waves over North America and
North Atlantic Ocean is performed using the mesoscale model MM5 for January 2003,
verified with Advanced Microwave Sounding Unit-A (AMSU-A) radiance observations
in the upper troposphere and lower stratosphere. According to the monthly mean
statistics, four regions of strong gravity wave activities are found both in the simulation
and the AMSU-A observations: northwestern Atlantic, Appalachian Mountains, Rocky
Mountains and Greenland, respectively. Those over the northwestern Atlantic Ocean are
strongly associated with the midlatitude baroclinic jet-front systems, while the other
three regions are apparently collocated with high topography.
Imbalance diagnosis and numerical sensitivity experiments of a strong gravity
wave event during January 18-22 show that the gravity waves are strongly linked to the
unbalanced flow in the baroclinic jet-front system. The gravity waves are usually
radiated from the upper tropospheric jet exit region with maximum nonlinear balance
equation residual ( Δ NBE; key indicator of flow imbalance), distinctly different from other surface sources. Flow imbalance related strongly to tropopause folding and
frontogenesis of the large-scale background flow. Similar wave characteristics are
simulated in experiments with different microphysics and grid resolutions. The Δ NBE is
again shown to be a good predictor for jet-front related gravity waves, suggesting its
potential application to gravity wave parameterizations for global and climate models.
36
Boston, Megan. "Reducing Residual Drift in Buckling-Restrained Braced Frames by Using Gravity Columns as Part of a Dual System." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3204.
Full textAbstract:
Severe earthquakes cause damage to buildings. One measure of damage is the residual drift. Large residual drifts suggest expensive repairs and could lead to complete loss of the building. As such, research has been conducted on how to reduce the residual drift. Recent research has focused on self-centering frames and dual systems, both of which increase the post-yield stiffness of the building during and after an earthquake. Self-centering systems have yet to be adopted into standard practice but dual systems are used regularly. Dual systems in steel buildings typically combine two types of traditional lateral force resisting systems such as bucking restrained braced frames (BRBFs) and moment resisting frames (MRFs). However, the cost of making the moment connections for the MRFs can make dual systems costly. An alternative to MRFs is to use gravity columns as the secondary system in a dual system. The gravity columns can be used to help resist the lateral loads and limit the residual drifts if the lateral stiffness of the gravity columns can be activated. By restraining the displacement of the gravity columns, the stiffness of the columns adds to the stiffness of the brace frame, thus engaging the lateral stiffness of the gravity columns. Three methods of engaging the stiffness of the gravity columns are investigated in this thesis; one, fixed ground connections, two, a heavy elastic brace in the top story, and three, a heavy elastic brace in the middle bay. Single and multiple degree of freedom models were analyzed to determine if gravity columns can be effective in reducing residual drift. In the single degree of freedom system (SDOF) models, the brace size was varied to get a range of periods. The column size was varied based on a predetermined range of post-yield stiffness to determine if the residual drift decreased with higher post-yield stiffness. Three and five story models were analyzed with a variety of brace and column sizes and with three different configurations to activate the gravity columns. Using gravity columns as part of a dual system decreases the residual drift in buildings. The results from the SDOF system show that the residual drift decreased with increased post-yield stiffness. The three and five story models showed similar results with less residual drift when larger columns were used. Further, the models with a heavy gravity column in the top story had the best results.
37
Lippa, Magdalena Anna [Verfasser], and Reinhard [Akademischer Betreuer] Genzel. "Interferometry in astronomy : the GRAVITY metrology system and galaxy evolution with the IRAM interferometer / Magdalena Anna Lippa ; Betreuer: Reinhard Genzel." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2018. http://d-nb.info/1168590817/34.
Full text
38
Roy, Michelle. "Investigation of Future Flow Reducer Sizes in Houses Added to an Existing Gravity Flow Water System to Ensure its Sustainability." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6580.
Full textAbstract:
Goal 6 of the United Nations Development Program’s new Sustainable Development Goals aims to ensure availability of clean water and sustainable management practices to all by the year 2030. Peace Corps Panama partners with communities in order to help provide sustainable water solutions to communities in need. Water, Sanitation, and Hygiene (WASH) Volunteers spend at least two years living in a community to identify and implement solutions to water problems and train local water committees on how to maintain their improved systems. A common solution for unequal distribution of flow in the distribution network of a gravity flow water system is through the installation of flow reducers before each faucet. These can be sized with the help of NeatWork, a free, downloadable compute software. In Panama, flow reducers (also referred to as orifices) are manufactured to create a perforated plastic diaphragm fitting placed in the distribution pipe or union section upstream of a faucet. They help ensure longevity of the aqueduct by balancing the flows between houses, thus, enabling continuous water flow for all users. An important characteristic of flow reducers is that while they can be installed in new water sys-tems, they can also be installed in existing systems to fix inequalities from inadequate original designs or extensions to the systems. However, little guidance exists for volunteers or commu-nities to ensure the sustainability of these projects. Accordingly, the object of this thesis was to investigate how adding houses to existing aqueducts would affect its serviceability and how to determine a way for communities to size the flow reducers for future houses.
The existing gravity flow water system in Santa Cruz, Panamá was surveyed including all the potential houses which were then analyzed using NeatWork. The results demonstrate that while it is better to include all potential locations during the initial survey, if it expands at an average growth rate, additional houses may decrease serviceability, but in a negligible way that will not affect the overall reliability of the distribution system.
Utilizing NeatWork, this research showed it is able to determine ideal sizes of flow reducers for additional houses that could be added. Patterns were identified and used to simplify flow reducer sizing so that community members could do it themselves. While most of the time, the ideal flow reducer size for a new house will be the same size as the flow reducer size that is installed in the closest house that is already connected to the aqueduct, sometimes this is not the case. This typically occurs towards the end of branches and in areas where not all flow reducer sizes are present. These areas are clearly identified to the water committee on a map of the distribution system that was provided to various water committee members. With this map and simple instructions, the Santa Cruz water committee can continue correctly adding flow reducers to new houses.
Through the research of this thesis, fabricating and installing flow reducers in the Santa Cruz water distribution system, and working alongside community members many lessons were learned about flow reducers and best practices. This knowledge has been converted into a guide about sustainable flow reducer projects. It has been left with current volunteers and the director of training for the WASH sector of Peace Corps Panama so that the volunteers can adapt the developed tools in their own communities.
39
Zhang, Yang. "Design and synthesis of mechanical systems with coupled units." Thesis, Rennes, INSA, 2019. http://www.theses.fr/2019ISAR0004/document.
Full textAbstract:
Ce mémoire traite de nouveaux principes de conception qui sont inspirés par le couplage de deux unités représentant les différentes structures mécaniques. Les critères de conception optimale et les types d'unités combinées sont différents. Cependant, toutes les tâches sont considérées dans le couplage de ces unités. L'examen critique présenté dans le premier chapitre est divisé en trois sections en raison de la nature des problèmes traités: les robots marcheurs, les compensateurs de gravité et les robots collaboratifs. Le deuxième chapitre traite du développement de robots marcheurs à actionneur unique, conçus par couplage de deux mécanismes ayant les fonctionnants de jambe. Basée sur l'algorithme génétique, la synthèse proposée permet d'assurer la reproduction de la trajectoire obtenue à partir de la marche humaine. Par l'ajustement des paramètres géométriques des unités conçues, il devient possible non seulement d'assurer une marche du robot à des pas variables, mais également de monter les escaliers. Ensuite la conception et la synthèse des équilibreurs pour les robots sont considérés. Un costume robotisé type exosquelette permettant d'aider aux personnes transportant des charges lourdes est examiné dans le chapitre suivant La conception proposée présente une symbiose d'un support rigide et léger et d'un système de câbles monté sur ce support. L'étude et l'optimisation statique et dynamique ont conduit aux tests sur un mannequin. Le dernier chapitre propose l'étude et 'optimisation d'un système couplé, comprenant un manipulateur équilibré à commande manuelle et un robot collaboratif. Le but d'une telle coopération est de manipuler de lourdes charges avec un cobotThis thesis deals with the design principles, which arc based on the coupling of two mechanical structures. The criteria for optimal design and the types of combined units are different. However, all the tasks are considered in coupling of given mechanical units. The critical review given in the first chapter is divided into three sections due to the nature of the examined problems: legged walking robots, gravity compensators used in robots and collaborative robots. Chapter two deals with the development of single actuator walking robots designed by coupling of two mechanisms. Based on the Genetic Algorithm, the synthesis allows one to ensure the reproduction of prescribed points of the given trajectory obtained from the walking gait. By adjusting the geometric parameters of the designed units, it becomes possible not only to operate the robot at variable steps, but also to climb the stairs. The next chapter deals with the design and synthesis of gravity balancers. A robotic exosuit that can help people carrying heavy load is the subject of chapter four. The proposed exosuit presents a symbiosis of two systems: rigid lightweight support and cable system. Static and dynamic studies and optimization are considered. Experiments are also carried out on a mannequin test bench. The last chapter presents a coupled system including a hand-operated balanced manipulator and a collaborative robot. The aim of such a cooperation is to manipulate heavy payloads with less powerful robots. Dynamic analysis of the coupled system is perfonned and methods for reducing the oscillation of the HOBM at the final phase of the prescribed trajectories are proposed
40
Pereira, De Sa Rui Carlos. "Respiration and cardio-respiratory interactions during sleep in space: influence of gravity." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210416.
Full textAbstract:
Le principal objectif de ce travail est l’étude de l’influence de la pesanteur sur la mécanique respiratoire et le contrôle de la respiration, ainsi que sur les interactions cardio-respiratoires pendant les différents stades du sommeil.
Le chapitre introductif présente le contexte général et les objectifs de la thèse. Des sections abordant le sommeil, la respiration, et l’interaction cardio-respiratoire y sont présentées, résumant l’état actuel des connaissances sur les effets de la pesanteur sur chacun de ces systèmes.
Dans le deuxième chapitre, l’expérience “Sleep and Breathing in microgravity”, qui constitue la source des données à la base de ce travail, est présentée en détail.
L’étude des signaux de longue durée requiert avant tout de disposer d’outils performants
d’analyse des signaux. La première partie de la thèse présente en détail deux algorithmes :un
algorithme de détection automatique d’événements respiratoires (inspiration / expiration)
basé sur des réseaux neuronaux artificiels, et un algorithme de quantification de l’amplitude
et de la phase de l’arythmie sinusale pendant le sommeil, utilisant la méthode des ondelettes.
La validation de chaque algorithme est présentée, et leur performance évaluée. Cette partie
inclut aussi des courtes introductions théoriques aux réseaux de neurones artificiels ainsi
qu’aux méthodes d’analyse temps–fréquence (Fourier et ondelettes).
Une approche similaire à celle utilisée pour la détection automatique d’événements respiratoires a été appliquée à la détection d’événements dans des signaux de vitesse du sang
dans l’artère cérébrale moyenne, mesures obtenues par Doppler transcrânien. Ceci est le
sujet de la thèse annexe.
Ces deux algorithmes ont été appliqués aux données expérimentales pour extraire des
informations physiologiques quant à l’impact de la pesanteur sur la mécanique respiratoire et
l’interaction cardio-respiratoire. Ceci constitue la deuxième partie de la thèse. Un chapitre
est consacré aux effets de l’apesanteur sur la mécanique respiratoire pendant le sommeil.
Ce chapitre a mis en évidence, pour tous les stades de sommeil, une augmentation de la
contribution abdominale en microgravité, suivi d’un retour progressif vers des valeurs observées avant le vol. L’augmentation initiale était attendue, mais l’adaptation progressive
observée ne peut pas être expliquée par un effet purement mécanique, et nous suggère la
présence d’un mécanisme d’adaptation central. Un deuxième chapitre présente les résultats
comparant l’arythmie sinusale pendant le sommeil avant le vol, en apesanteur et après le retour sur terre. Le rythme cardiaque pendant le sommeil dans l’espace présente une moindre
variabilité. Les différences NREM–REM observées sur terre pour les influences vagales et sympathiques sont accentuées dans l’espace. Aucun changement significatif n’est présent pour
le gain et la différence de phase entre les les signaux cardiaque et respiratoire en comparant
le sommeil sur terre et en apesanteur.
La dissertation termine par une discussion générale du travail effectué, incluant les prin-
cipales conclusions ainsi que les perspectives qui en découlent.
Doctorat en Sciences biomédicales et pharmaceutiques
info:eu-repo/semantics/nonPublished
41
Ge, Shengjie. "GPS radio occultation and the role of atmospheric pressure on spaceborne gravity estimation over Antarctica." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1149070384.
Full text
42
Kumar, Neela Shiva. "Cellular Mechanisms of Gravitropism in ARG1 (Altered Response to Gravity) Mutants of Arabidopsis Thaliana." Oxford, Ohio : Miami University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1218220626.
Full text
43
Le, gall Anne. "Influence de la graviception vestibulaire sur le développement et les fonctions cognitivo-motrices à l'âge adulte : étude longitudinale chez un modèle murin vestibulo-déficient." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC421.
Full textAbstract:
La gravité terrestre est une contrainte mécanique fondamentale exercée sur les organismes vivants et contre laquelle nous avons adapté nos stratégies de posture et de locomotion ainsi que toutes les régulations métaboliques et cardiovasculaires. Outre le stimulus mécanique direct, la gravité est mesurée par l'organe vestibulaire, premier système sensoriel à émerger chez les protochordés il y a environ 500 millions d'années, aussi précocement que le système visuel. Le système vestibulaire a alors été asservi aux fonctions d'équilibre et de stabilisation du regard, par des réflexes posturaux et oculaires, fonctions récemment enrichies d’un rôle clé dans la cognition spatiale et sociale chez l’adulte. Ses capacités d’encodage des mouvements de la tête, des accélérations du corps et de la gravité terrestre font de ce système un acteur majeur dans la perception de la verticalité, la navigation, l’orientation et la mémorisation spatiale. Nous avons émis l'hypothèse que la perception sensorielle vestibulaire de la gravité via les otolithes pourrait jouer un rôle crucial non seulement chez l’adulte mais également dans les premières étapes du développement des fonctions sensorimotrices et cognitives. Pour la première fois, nous avons étudié un modèle de souris original (souris Head-tilt, B6Ei.GL-Nox3Het / J) présentant une absence congénitale sélective de gravisenseurs vestibulaires. Les souris présentaient un retard dans l'acquisition des réflexes sensorimoteurs, des capacités d’orientation spatiale par guidage olfactif, d'une communication mère-petits par ultrasons alors que les soins maternels étaient normaux. Un retard dans la locomotion et des troubles hyperactifs avec stéréotypies ont également été montré. Nous démontrons ainsi que le développement des individus sur Terre possède une période critique dépendante de la perception sensorielle vestibulaire de la gravité, au moins entre les jours post-nataux 6 à 10 chez les rongeurs. Les informations otolithiques jouent également un rôle clé chez l’adulte dans les fonctions motrices, les processus mnésiques spatiaux et non spatiaux et dans la régulation émotionnelle. Une corrélation entre ces troubles et le retard développemental a été mis en évidence. Nous travaillons actuellement sur les effets de stimulations sensorielles précoces sur le développement et les fonctions adultes chez la souris Het ainsi que sur la caractérisation structurale et fonctionnelle au niveau cérébral des atteintes développementales et comportementales observées. Les observations chez les souris Het corroborent les symptômes rapportés chez les enfants vestibulo-déficients, soutenant le besoin d'un meilleur dépistage des maladies vestibulaires pendant l'enfance. De manière intéressante, les symptômes de ces souris correspondent à ceux présentés par des modèles murins validés d'autisme et réactualiseraient l’importance de la graviception vestibulaire dans la physiopathologie et la thérapie des troubles du spectre autistique (TSA) et autres maladies neurodégénératives au cours du développementEarth’s gravity is a fundamental mechanical constraint for living organisms against which we have adapted our strategies of posture and locomotion as well as all metabolic and cardiovascular regulations. Beyond the mechanical stimulus, the vestibular organ is the first sensory system to emerge in protochordates about 500 million years ago, as early as the visual system, encoding the gravity strength into the brain. The vestibular system has since then been devoted to balance and gaze stabilization supported by postural and ocular reflexes, recently fortified with a key role in spatial and social cognition in adults. Its encoding abilities of head movements, body accelerations and Earth's gravity make this system a major player in the perception of verticality, navigation, orientation and spatial memorization. We have hypothesized that vestibular sensory perception of gravity might play a crucial role not only in adults, but also during the first stages of development in both sensorimotor and cognitive functions. For the first time, we have investigated an original mouse model (Head-Tilt mice, B6Ei.GL-Nox3Het/J) with selective congenital absence of vestibular gravisensors. Our data highlights that mouse pups suffered from a delay in the acquisition of sensorimotor reflexes, spatial olfactive guidance, path integration and ultrasonic communication while maternal care remained normal. In addition, a delay in locomotor development and the appearance of were observed during the late stage of development. We demonstrate that development on Earth has a critical period dependent on the vestibular sensory perception of gravity, at least between postnatal days 6 to 10 in rodents. We have shown that otolithic information plays a key role in the adult motor functions, spatial and non-spatial memory processes, reference frames choice but also in emotional regulation. These disorders have been correlated with early developmental delay. We are currently working on the effects of early sensory stimulation on development and adult functions in our Het mouse model as well as on the structural and functional characterization at the cerebral level of observed developmental and behavioral impairments. Observations in Het mice corroborate with symptoms reported in vestibulo-deficient children, supporting the need for better screening of vestibular diseases during childhood. Remarkably, the symptoms of our vestibulo-congenital deficient mice investigated here matched with the profile of validated mouse models of autism and re-update the significance of vestibular graviception in the physiopathology and therapy of autism spectrum disorders during its development
44
Kolář, Tomáš. "Studie odkanalizování vybrané obce." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-371960.
Full textAbstract:
The subject of this diploma thesis is a study of two variants of sewer network of Cetechovice. Variant solutions include the use of existing segments supplemented by new gravitational or pressure sections. The proposed variant solutions are then economically assessed.
45
Wilson, Earle Anthony. "Investigation of renewable, coupled solar-hydrogen fuel generation with thermal management systems suitable for equatorial regions." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4508.
Full textAbstract:
Solar Energy and Hydrogen (energy carrier) are possible replacement options for fossil fuel and its associated problems of availability and high prices which are devastating small, developing, oil-importing economies. But a major drawback to the full implementation of solar energy, in particular photovoltaic (PV), is the lowering of conversion efficiency of PV cells due to elevated cell temperatures while in operation. Also, hydrogen as an energy carrier must be produced in gaseous or liquid form before it can be used as fuel; but its‟ present major conversion process produces an abundance of carbon dioxide which is harming the environment through global warming. In search of resolutions to these issues, this research investigated the application of Thermal Management to Photovoltaic (PV) modules in an attempt to reverse the effects of elevated cell temperature. The investigation also examined the effects of coupling the thermally managed PV modules to a proton exchange membrane (PEM) Hydrogen Generator for the production of hydrogen gas in an environmentally friendly and renewable way. The research took place in Kingston, Jamaica. The thermal management involved the application of two cooling systems which are Gravity-Fed Cooling (GFC) and Solar-Powered Adsorption Cooling (SPAC) systems. In both systems Mathematical Models were developed as predictive tools for critical aspects of the systems. The models were validated by the results of experiments. The results of the investigation showed that both cooling systems stopped the cells temperatures from rising, reversed the negative effects on conversion efficiency, and increased the power output of the module by as much as 39%. The results also showed that the thermally managed PV module when coupled to the hydrogen generator impacted positively with an appreciably increase of up to 32% in hydrogen gas production. The results of this work can be applied to the equatorial belt but also to other regions with suitable solar irradiation. The research has contributed to the wider community by the development of practical, environmentally friendly, cost effective Thermal Management Systems that guarantee improvement in photovoltaic power output, by introducing a novel way to use renewable energy that has potential to be used by individual household and/or as cottage industry, and by the development of Mathematical Tools to aid in photovoltaic power systems designs.
46
Klíma, Aleš. "Odkanalizování obce do 2 tisíc obyvatel." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226151.
Full textAbstract:
In this thesis I deal with the drainage of Hněvošice village (the village up to 2000 inhabitants). I made a technical and economic evaluation of three possible drainage systems (gravity sewers, vacuum sewers, pressure sewers). After assessing I have chosen one of them, the gravity sewers. Then I made a complete design of the sewers including design sewerage treatment plant.
47
Briones, Maria. "Validating the Accuracy of Neatwork, a Rural Gravity Fed Water Distribution System Design Program, Using Field Data in the Comarca Ngöbe-Bugle, Panama." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7268.
Full textAbstract:
Despite the sustainable development goals to increase access to improved water there are still 884 million people in the world without access to an improved water source (WHO, 2017). One method to improve access to water in rural, mountainous areas, is through construction of gravity fed water distribution systems. These systems should be designed based upon fundamental principles of hydraulics. One method of doing so in a time efficient manner with minimal engineering knowledge is to utilize a downloadable computer program such as Neatwork, which aids in design of rural, gravity fed water distribution systems and has been used by volunteers in Peace Corps Panama for years. It was the goal of this research to validate the results of the Neatwork program by comparing the flow results produced in the simulation program with flow results measured at tap stands of a rural gravity fed water distribution system in the community of Alto Nube, Comarca Ngöbe Bugle, Panama.
The author measured flow under default Neatwork conditions of 40% faucets open in the system (in the field an equivalent of 8 taps) to have an initial basis as to whether the Neatwork program and field conditions yielded corresponding flows. The second objective would be to vary the number of taps open if the default condition did not produce comparable results between the field and the simulation, to pinpoint if under a certain condition of open faucets in the system the two methods would agree. The author did this by measuring flow at varying combinations from 10-100% of the open taps in the system (2-20 taps). Lastly the author observed the flow differences in the Neatwork program against the field flows, when the elevation of water in the water reservoir is set to the Neatwork default, where elevation of water is the tank outlet (at the bottom of the tank) versus when the elevation is established at the overflow at the tank (at the top of the tank) for the case of two taps open.
The author used paired t-tests to test for statistical difference between Neatwork and field produced flows. She found that for the default condition of 40% taps open and all other combinations executed between 30-80% taps open, the field and Neatwork flows did not produce statistically similar results and, in fact, had the tendency to overestimate flows. The author also found that the change in water elevation in the storage tank from outlet to overflow increased the flow at the two taps measured by 0.140 l/s and 0.145 l/s and in this case, did not change whether the flows at these taps were within desired range (0.1 -0.3 l/s). Changing the elevation of the water level in the tank in the Neatwork program to correspond to a “full” tank condition is not recommended, as assuming an empty tank will account for seasonal changes or other imperfections in topographical surveying that could reduce available head at each tap. The author also found that the orifice coefficients, θ, of 0.62 and 0.68, did not demonstrate more or less accurate results that coincided with field measurements, but rather showed the tendency of particular faucets to prefer one coefficient over the other, regardless of combination of other taps open in the system.
This study demonstrates a consistent overestimation in flow using the computer program Neatwork. Further analysis on comparisons made show that between field and flow results across each individual faucet, variations between Neatwork and the field were a result of variables dependent upon the tap, such as flow reducers or errors in surveying. Flow reducers are installed before taps to distribute flow equally amongst homes over varying distances and elevations and are fabricated using different diameter orifices depending on the location of the tap. While Neatwork allows the user to simulate the effect of these flow reducers on tap flow, it may not account for the imperfect orifices made by the simple methods used in the field to make such flow reducers.
The author recommends further investigation to be done on the results of field flow versus Neatwork simulated flow using other methods of flow reducer fabrication which produce varying degrees of accuracy in orifice sizing. The author also recommends executing these field measurements over a greater sample size of faucets and more randomized combination of open/closed taps to verify the results of this research. More work should be done to come up with a practical solution for poor and rural communities to fabricate and/or obtain more precisely sized flow reducers. A full sensitivity analysis of the input variables into the Neatwork program should be performed to understand the sensitivity of varying each input.
48
Pazinatto, Flavia Bittencourt. "Influência do posicionamento do espécime na resistência adesiva à dentina e na espessura da camada de sistemas adesivos." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/25/25131/tde-07022007-144601/.
Full textAbstract:
Investigou-se a influência da inclinação das paredes de dentina (paralela ou perpendicular à ação da gravidade) e da variação regional dos espécimes (terços cervical ou oclusal) na resistência adesiva e na espessura da camada de adesivo. Vinte e cinco molares humanos foram seccionados no sentido mésio-distal e paralelamente ao seu longo eixo, obtendo-se secções vestibulares e linguais, as quais foram lixadas produzindo-se superfícies planas de dentina. Sistemas adesivos (Adper Single Bond-SB e Prime & Bond 2.1- PB2.1) foram aplicados na dentina, ora paralelamente ora perpendicularmente à ação da gravidade, padronizando-se o volume de adesivo (3,5 µl por gota) através do uso de uma micropipeta e seguindo-se as instruções dos fabricantes. Os grupos de estudo foram: 1A (SB, paralelo), 1B (SB, perpendicular), 2A (PB2.1, paralelo) e 2B (PB2.1, perpendicular). Após 24h de armazenamento em água deionizada a 37°C, espécimes foram preparados na forma de palitos de dentina com área adesiva de 0,8 mm2, aproximadamente. Na seqüência, foi determinada a espessura do adesivo de cada espécime, em micrômetros (µm), sob microscopia óptica (200X de aumento) e auxílio do programa Image Pro-Plus 4.5. Posteriormente, os espécimes foram submetidos à microtração sob velocidade de 0,5 mm/min. Todos os espécimes fraturados foram examinados sob microscopia óptica (40X de aumento) para a determinação dos planos de fratura. Os dados coletados foram submetidos aos testes ANOVA a 1 e 2 critérios e SNK (? = 0,05). Para determinação da correlação entre resistência adesiva e espessura do adesivo foi utilizado o teste de Correlação de Pearson. Os valores médios (MPa±d.p.) de resistência adesiva dos grupos 2A (52,93±15,19) e 2B (52,27±16,54) foram superiores àqueles dos grupos 1A (39,09±12,90) e 1B (32,94±12,42), independente da inclinação das paredes de dentina dos mesmos. Não houve diferença nos valores de resistência adesiva à dentina, independente da variação regional do espécime. Os valores médios (µm±d.p.) de espessura da camada de adesivo dos grupos 1A (11,24±2,92) e 1B (18,11±7,31) foram superiores àqueles dos grupos 2A (4,20±1,81) e 2B (3,87±1,29) (p > 0,05). O grupo 1B promoveu os maiores valores de espessura de adesivo, seguido do grupo 1A. As espessuras do adesivo nos grupos 2A e 2B apresentaram-se similares entre si. Houve influência da variação regional do espécime na espessura de adesivo somente para o grupo 1B. Não houve correlação entre resistência adesiva e espessura de adesivos para ambos SB e PB2.1 (r = -0,224, p = 0,112 e r = 0,099, p = 0,491, respectivamente). Conclui-se que a influência da inclinação das paredes de dentina e da variação regional dos espécimes na espessura da camada de adesivo é material-dependente, porém não influem na resistência adesiva dos sistemas adesivos à dentina.To determine the effect of the inclination of dentin surfaces (parallel or perpendicular to the force of gravity) and the regional variation of specimens (cervical or occlusal thirds) on the dentin bond strength and adhesive layer thickness. Twenty-five extracted human molars were sectioned in a mesio-distal direction to expose flat dentin. Standardized drop volumes of adhesive systems (Single Bond-SB and Prime & Bond 2.1-PB2.1) were applied to dentin according to manufacturers instructions. Teeth were randomly divided into the following groups: 1A (SB, parallel), 1B (SB, perpendicular), 2A (PB2.1, parallel) and 2B (PB2.1, perpendicular). Teeth were stored in 37°C distilled water for 24h and then serially sectioned to obtain sticks with cross-sectional area of approximately 0.8 mm2 for microtensile bond strength test (MTBS). The thickness of adhesive layer of the MTBS specimen was determined in a light microscope at 200X magnification. Forty-eight hours after adhesion procedures the specimens were subjected to MTBS at a crosshead speed of 0.5 mm/min. After testing, the fracture modes of each specimen were determined by examination under a 40X magnification. One and two-way ANOVA and Student- Newman-Keuls-SNK tests were performed do determine differences in MTBS and in adhesive layer thickness among groups. The correlation between MTBS and adhesive layer thickness was compared with Pearson Product Moment Correlation ('alfa' = 0.05). Mean values (MPa±s.d.) for bond strength were higher for groups 2A (52.93±15.19) and 2B (52.27±16.54) than for groups 1A (39.09±12.90) and 1B (32.94±12.42), regardless of the position of dentin surfaces. There was no difference in MTBS, despite the regional variation of specimens. The thickness of adhesive systems (µm±s.d.) was higher for groups 1A (11.24±2.92) and 1B (18.11±7.31) than those for groups 2A (4.20±1.81) and 2B (3.87±1.29). Group 1B provided the greater mean values of adhesive thickness followed by the Group 1A. Similar adhesive thicknesses were found for Groups 2A and 2B, but significantly lower than the other groups. There was a significant influence of the regional variation of specimens on the adhesive thickness of group 1B. No correlation was found between bond strength and adhesive layer thickness for both SB and PB 2.1 (r = -0.224, p = 0.112 and r = 0.099, p = 0.491, respectively). The inclination of dentin surface and the regional variation of specimens on the adhesive layer thickness are materialdependent. These variables do not influence the adhesive systems bond strength to dentin.
49
Dahllöf, Karin. "Trycksatt avloppssystem och självfallssystem i Fredrikstad kommun. En jämförande fallstudie." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-229810.
Full textAbstract:
Krav om förbättrad spillvattenrening och städer som förgrenar sig över större områden är några av anledningarna till att dagens avloppsledningsnät får allt längre ledningssträckor. Att med gravitationens hjälp föra avloppsvatten framåt kräver ett kontinuerligt fall som vid långa avstånd kan innebära mycket schaktning, den ekonomiskt mest belastande delen vid nyinstallation av avloppsledningsnät. Ett fördelaktigt alternativ kan vara trycksatt avloppssystem, som sedan 70-talet har kompletterat de traditionella självfallssystem i kuperade och bergiga områden. På senare tid har trycksatt avloppsystem fått större användningsområde utanför sina etablerade bruksområden med anledning av skärpta krav på rening och kostnadseffektivitet. Självfallssystem är dock det mest använda avloppssystemet i urbana områden. För ett bostadsområde i utkanten av centrum, utanför de båda systemens vedertagna användningsområden, vore det därför intressant att undersöka vilket av avloppssystemen som är bäst lämpat. För VA-branschen generellt vore det också intressant att utreda hur de båda systemen står sig vid en jämförelse. Med anledning av detta var syftet med examensarbetet att jämföra trycksatt avloppssystem med självfallssystem på grundval av ekonomi, miljö och kapacitet. I tillägg undersöktes om några generella slutsatser kunde fastställas utifrån fallstudien. Undersökningen baserades på ett bostadsområde i utkanten av Fredrikstad centrum, som nyligen projekterats med självfall. Ett teoretiskt trycksatt avloppssystem projekterades. Ekonomi värderades utifrån drift- och underhållskostnader samt grund- och reinvesteringskostnader. Kapaciteten jämfördes numeriskt och via dimensioneringsmodeller. Vad gäller den miljömässiga jämförelsen utvärderades systemet med hjälp av rapporter utgivna av Svenskt Vatten och Norsk Vann. Det planerades en utbyggnad för området till dubbla antalet fastigheter vilket visade sig bli avgörande för det ekonomiska resultatet. Den vitala faktorn var de höga investerings- och driftskostnaderna för pumpenheterna vilket gjorde självfallssystemet mer ekonomiskt lämpligt. Även ur ett miljömässigt perspektiv var självfallssystemet marginellt bättre, givet att riskeffekterna inte rankades inbördes. Kapacitetsmässigt dimensioneras självfallssystem för nästan det dubbla flödet jämfört med trycksatt system, vilket ger det trycksatta systemet en kapacitet mer anpassad till behovet. Generellt sett antydde resultatet att trycksatt system var mer gynnsamt vid glesare bebyggelse.As a result of stricter treatment requirements and city expantion the length of the sewer network is steadily increasing. To drain wastewater by gravity requires a continuous slope which often results in great excavation - a very costly part in the process. An advantageous alternative could be a pressurized sewer system, which has been a useful complement to traditional gravity systems in hilly or rocky areas since the 70’s. Even though pressurized sewer systems lately have tended to be more frequently used outside their common application area due to stricter requirements on treatment and cost-efficiency, gravity systems are still the most common sewer system in urban areas. Concerning this, it would be intresting to investigate which of the two systems that suites a residental area on the outskirts of a city center best, since the area is outside the traditional usage of the two established systems. In addition it would be interesting for the wastewater industry in general to investigate how the two systems compare. For this reason the aim of this master thesis was to compare pressure sewer systems with gravity systems on the basis of economy, environment and capacity. In addition, it was examined whether any general conclusions could be determined from the case study. The survey was based on a residental area in the outskirts of Fredrikstad city center, recently designed with a gravity system. A theoretical pressure sewer system was designed. Economy was evaluated based on the operating and maintenance costs and basic and reinvestment costs. The capacity was compared numerically and through design templates. As for the environmental comparison, an evaluation was done on the basis of reports from the Swedish Water & Wastewater Association and Norwegian Water BA. An expansion to double the number of real properties was planned for the area of study, which proved to be crucial to the financial results. The gravity system was most appropriate from an economic standpoint and the vital factor was the high investment and operating costs for the pumping units. Even from an environmental point of view, the gravity system was maginally better. Given that the risk effects are not ranked relative to each other. In terms of capacity the gravity system was dimensioned for almost twice the flow compared to the pressure sewer systems, which gave the pressure sewer system a more adusted capacity. The result indicated that the pressure sewer system is favorable in densely built flexible areas.
50
Hudson, Donna Louise. "The Effects of Lower Body Negative Pressure on the Cardiovascular System: The Relationships of Gender and Aerobic Fitness." Thesis, North Texas State University, 1986. https://digital.library.unt.edu/ark:/67531/metadc935602/.
Full textAbstract:
Sixteen males and sixteen females were recruited for this study; eight of each gender were aerobically trained athletes; the remaining eight were untrained control subjects. Each subject performed a maximal exercise stress test for aerobic capacity (VO2max). On a separate day the blood volume and the cardiovascular responses to progressive (0 to -50 torr) lower body negative pressure (LBNP) were determined. The female subjects were observed to be significantly more tolerant of the LBNP than the male subjects. No differences between groups were observed in changes in leg volume, cardiac index, blood pressure, or heart rate during LBNP. However, the females, in comparison to the males, maintained stroke index at a higher level, and increased regional vasoconstriction more, during the LBNP induced hypotensive stress. These findings suggest that female subjects withstand LBNP to -50 torr better than male subjects.