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open access

Analyze and Rebuild an Apparatus to Gauge Evaporative Cooling Effectiveness of Micro-Porous Barriers.

Description: The sample used for evaporative cooling system is Fabric defender 750 with Shelltite finish. From the experimental data and equations we have diffusion coefficient of 20.9 ± 3.71 x 10-6 m2/s for fabric with one layer with 17%-20% fluctuations from the theory, 27.8 ± 4.5 x 10-6 m2/s for fabric with two layers with 6%-14% fluctuations from the theory and 24.9 ± 4.1 x 10-6 m2/s for fabric with three layers with 13%-16% fluctuations from the theory. Since the thickness of the fabric increases so… more
Date: December 2008
Creator: Mohiti Asli, Ali
Item Type: Refine your search to only Thesis or Dissertation
open access

Errors in skin temperature measurements.

Description: Numerical simulation is used to investigate the accuracy of a direct-contact device for measuring skin-surface temperature. A variation of thermal conductivity of the foam has greater effect on the error rather than a variation of the blood perfusion rate. For a thermal conductivity of zero, an error of 1.5 oC in temperature was identified. For foam pad conductivities of 0.03 and 0.06 W/m-oC, the errors are 0.5 and 0.15 oC. For the transient study, with k=0 W/m-oC, it takes 4,900 seconds fo… more
Date: December 2008
Creator: Dugay, Murielle
Item Type: Refine your search to only Thesis or Dissertation
open access

Quasi-Three Dimensional Experiments on Liquid-Solid Fluidized Bed of Three Different Particles in Two Different Distributors

Description: This thesis is an experimental study of the fluidization of binary mixture in particulate flows. A fluidized bed with two distributors was built with water being used as carrying fluid. Three types of solid particles of nylon, glass and aluminum of the same size and different densities are used in the experiments. The wall effect on a single particle fluidization, the fluidization of binary mixture of large density difference (nylon and aluminum of density ratio of 0.42), and the fluidization… more
Date: December 2009
Creator: Obuseh, Chukwuyem Charles
Item Type: Refine your search to only Thesis or Dissertation
open access

Ultrafast Laser Sampling of a Plant Tissue and ion Conductivity Measurement for Investigation of Light Stress Generation Mechanisms

Description: In this study we applied ultra-short laser pulses on a biological sample (Arabidopsis), in order to cut it precisely in a square pattern and subsequently use it for studying stress generation mechanisms. For this purpose, we utilized femtosecond laser pulses at 100 fs pulse width and 80 MHz repetition rate. We took two processing parameters into consideration such as laser power, laser exposure time which is related to the stage speed. Therefore, we were able to find the laser optimum condition… more
Date: August 2010
Creator: Abtahi, Seyed Ali
Item Type: Refine your search to only Thesis or Dissertation
open access

Experimental Study on Fluidization of Biomass, Inert Particles, and Biomass/Sand Mixtures

Description: Fluidization of biomass particles is an important process in the gasification, pyrolysis and combustion in order to extract energy from biomass. Studies on the fluidization of biomass particles (corn cob and walnut shell), inert particles (sand, glass bead, and alumina), which are added to facilitate fluidization of biomass, and biomass/sand mixture were performed. Experiments were carried out in a 14.5 cm internal diameter cold flow fluidization bed to determine minimum fluidization velocities… more
Date: May 2011
Creator: Paudel, Basu
Item Type: Refine your search to only Thesis or Dissertation
open access

High-Precision Micropipette Thermal Sensor for Measurement of Thermal Conductivity of Carbon Nanotubes Thin Film

Description: The thesis describes novel glass micropipette thermal sensor fabricated in cost-effective manner and thermal conductivity measurement of carbon nanotubes (CNT) thin film using the developed sensor. Various micrometer-sized sensors, which range from 2 µm to 30 µm, were produced and tested. The capability of the sensor in measuring thermal fluctuation at micro level with an estimated resolution of ±0.002oC is demonstrated. The sensitivity of sensors was recorded from 3.34 to 8.86 µV/oC, which is … more
Date: August 2011
Creator: Shrestha, Ramesh
Item Type: Refine your search to only Thesis or Dissertation
open access

Energy Usage While Maintaining Thermal Comfort : A Case Study of a UNT Dormitory

Description: Campus dormitories for the University of North Texas house over 5500 students per year; each one of them requires certain comfortable living conditions while they live there. There is an inherit amount of money required in order to achieve minimal comfort levels; the cost is mostly natural gas for water and room heating and electricity for cooling, lighting and peripherals. The US Department of Energy has developed several programs to aid in performing energy simulations to help those interest… more
Date: December 2011
Creator: Gambrell, Dusten
Item Type: Refine your search to only Thesis or Dissertation
open access

Analysis of Sources Affecting Ambient Particulate Matter in Brownsville, Texas

Description: Texas is the second largest state in U.S.A. based on geographical area, population and the economy. It is home to several large coastal urban areas with major industries and infrastructure supporting the fossil-fuel based energy sector. Most of the major cities on the state have been impacted by significant air pollution events over the past decade. Studies conducted in the southern coastal region of TX have identified long range transport as a major contributor of particulate matter (PM) pol… more
Date: May 2012
Creator: Diaz Poueriet, Pablo
Item Type: Refine your search to only Thesis or Dissertation
open access

Evaluation of Fine Particulate Matter Pollution Sources Affecting Dallas, Texas

Description: Dallas is the third largest growing industrialized city in the state of Texas. the prevailing air quality here is highly influenced by the industrialization and particulate matter 2.5µm (PM2.5) has been found to be one of the main pollutants in this region. Exposure to PM2.5 in elevated levels could cause respiratory problems and other health issues, some of which could be fatal. the current study dealt with the quantification and analysis of the sources of emission of PM2.5 and an emission inv… more
Date: May 2012
Creator: Puthenparampil Koruth, Joseph
Item Type: Refine your search to only Thesis or Dissertation
open access

Laminar Natural Convection From Isothermal Vertical Cylinders

Description: Laminar natural convection heat transfer from the vertical surface of a cylinder is a classical subject, which has been studied extensively. Furthermore, this subject has generated some recent interest in the literature. In the present investigation, numerical experiments were performed to determine average Nusselt numbers for isothermal vertical cylinders (103 < RaL < 109, 0.5 < L/D <10, and Pr = 0.7) with and without an adiabatic top in a quiescent ambient environment which will allow for plu… more
Date: August 2012
Creator: Day, Jerod
Item Type: Refine your search to only Thesis or Dissertation
open access

Simulation Study of Tremor Suppression and Experiment of Energy Harvesting with Piezoelectric Materials

Description: The objective of this research is to develop a wearable device that could harvest waste mechanical energy of the human hand movement and utilize this energy to suppress wrist tremors. Piezoelectric material is used to measure the hand movement signals, and the signal of wrist tremor is filtered to be utilized to suppress the tremor. In order to conduct the experiment of energy harvesting and tremor suppression, an experimental rig was fabricated. Two types of piezoelectric materials, PVDF (poly… more
Date: August 2012
Creator: Ou, Jianqiang
Item Type: Refine your search to only Thesis or Dissertation
open access

Estimation of Aircraft Emissions for the Corpus Christi International Airport, Corpus Christi, Texas

Description: Commercial aviation is a vital part of the United States economy. It generates over $1 trillion annually, which is more than 5% of the U.S. GDP, and produces approximately 10 million jobs. Every year there is an increase in commercial air traffic. This is attributed to expanding trade between states and other countries, which requires larger amounts of cargo aircraft in operation, and also catering to the growing number of middle and upper class passengers who travel for business and pleasure p… more
Date: May 2013
Creator: Thomas, Gregson Johann
Item Type: Refine your search to only Thesis or Dissertation
open access

Optical Transparent Pmma Composite Reinforced By Coaxial Electrospun Pan Hollow Nanofibers

Description: Electrospinning has been recognized as an efficient technique for the fabrication of polymer fibers. These electrospun fibers have many applications across a broad range of industries. In this research, optical transparent composites were successfully fabricated by embedding polyacrylonitrile (PAN) hollow nanofibers into poly (methyl methacrylate) (PMMA) matrix. The hollow PAN nanofibers were prepared by coaxial electrospinning. The PAN was used as the shell solution, and the mineral oil was us… more
Date: May 2013
Creator: Antoine, Donley
Item Type: Refine your search to only Thesis or Dissertation
open access

Thermal Characterization of Austenite Stainless Steel (304) and Cnt Films of Varying Thickness Using Micropipette Thermal Sensors

Description: Thermal transport behavior of austenite stainless steel stripe (304) and the carbon nano-tubes (CNTs) films of varying thickness are studied using a micropipette thermal sensor. Micropipette sensors of various tip sizes were fabricated and tested for the sensitivity and reliability. The sensitivity deviated by 0.11 for a batch of pipette coated under same physical vapor deposition (PVD) setting without being affected by a tip size. Annealing, rubber coating and the vertical landing test of the … more
Date: May 2013
Creator: Dangol, Ashesh
Item Type: Refine your search to only Thesis or Dissertation
open access

Using a Multimodal Sensing Approach to Characterize Human Responses to Affective and Deceptive States

Description: Different ways to measure human affective and deceptive reactions to stimulus have been developed. One method is a multimodal approach using web camera, thermal imaging camera and physiological sensors data to extract different features in the human face (verbal and non-verbal behavior) such as breathing rate, heart rate, face temperature, skin conductance, eye tracking, language analysis and facial expressions among others. Human subjects from different ages and ethnicity were exposed to two d… more
Date: May 2013
Creator: Narvaez-Valle, Alexis
Item Type: Refine your search to only Thesis or Dissertation
open access

Effect of Dispersed Particles and Branching on the Performance of a Medium Temperature Thermal Energy Storage System

Description: The main objective of my thesis is to develop a numerical model for small-scale thermal energy storage system and to see the effect of dispersing nano-particles and using fractal-like branching heat exchanger in phase change material for our proposed thermal energy storage system. The associated research problems investigated for phase change material (PCM) are the low thermal conductivity and low rate of heat transfer from heat transfer fluid to PCM in thermal energy storage system. In this st… more
Date: August 2013
Creator: Hasib, A. M. M. Golam
Item Type: Refine your search to only Thesis or Dissertation
open access

Investigation of an Investment Casting Method Combined with Additive Manufacturing Methods for Manufacturing Lattice Structures

Description: Cellular metals exhibit combinations of mechanical, thermal and acoustic properties that provide opportunities for various implementations and applications; light weight aerospace and automobile structures, impact and noise absorption, heat dissipation, and heat exchange. Engineered cell topologies enable one to control mechanical, thermal, and acoustic properties of the gross cell structures. A possible way to manufacture complex 3D metallic cellular solids for mass production with a relativel… more
Date: August 2013
Creator: Kodira, Ganapathy D.
Item Type: Refine your search to only Thesis or Dissertation
open access

A Performance Analysis of Solar Chimney Passive Ventilation System in the Unt Zero Energy Lab

Description: The purpose of this investigation is to find out suitability of the solar chimney natural ventilation system in a Zero Energy Lab located at the University of North Texas campus, to figure out performance of the solar chimney. Reduction in the heating and ventilation and air conditioning energy consumption of the house has been also analyzed. The parameters which are considered for investigation are volumetric flow rate of outlet of chimney, the absorber wall temperature and glass wall tempera… more
Date: August 2013
Creator: Talele, Suraj H.
Item Type: Refine your search to only Thesis or Dissertation
open access

Performance Analysis of Two Alternative Hvac Systems for the Unt Zero Energy Lab

Description: This paper covers the simulation and comparison among three different HVAC (heating, ventilation & air conditioning)systems to achieve the goal of finding the most effective HVAC among these three in terms of human comfort, efficiency and cost considering North Texas climate. In the Zero Energy Lab at the University of North Texas, Denton, TX, the HVAC system of the building assembles with geothermal heat source. Here, water to water heat pump with radiant floor and water to air heat pump with … more
Date: August 2013
Creator: Hasib, Naimee
Item Type: Refine your search to only Thesis or Dissertation
open access

Sensitivity and Uncertainty Analysis of Occupancy-related Parameters in Energy Modeling of Unt Zero Energy Lab

Description: The study focuses on the sensitivity and uncertainty analysis of occupancy-related parameters using Energyplus modeling method. The model is based on a real building Zero Energy Lab in Discovery Park, at University of North Texas. Four categories of parameters are analyzed: heating/cooling setpoint, lighting, equipment and occupancy. Influence coefficient (IC) is applied in the sensitivity study, in order to compare the impact of individual parameter on the overall building energy consumption. … more
Date: August 2013
Creator: Xiong, Guangyuan
Item Type: Refine your search to only Thesis or Dissertation
open access

Characterization of Viscoelastic Properties of a Material Used for an Additive Manufacturing Method

Description: Recent development of additive manufacturing technologies has led to lack of information on the base materials being used. A need arises to know the mechanical behaviors of these base materials so that it can be linked with macroscopic mechanical behaviors of 3D network structures manufactured from the 3D printer. The main objectives of my research are to characterize properties of a material for an additive manufacturing method (commonly referred to as 3D printing). Also, to model viscoelasti… more
Date: December 2013
Creator: Iqbal, Shaheer
Item Type: Refine your search to only Thesis or Dissertation
open access

Multi-year Operation Effect of Geothermal Heat Exchanger on Soil Temperature for Unt Zero Energy Lab

Description: Ground source heat pump (GSHP) uses earth’s heat to heat or cool space. Absorbing heat from earth or rejecting heat to the earth, changes soil’s constant temperature over the multiple years. In this report we have studied about Soil temperature change over multiple years due to Ground loop heat exchanger (GLHE) for Zero Energy Research Laboratory (ZØE) which is located in Discovery Park, University of North Texas, Denton, TX. We did 2D thermal analysis GLHP at particular Depth. For simulation w… more
Date: December 2013
Creator: Walikar, Vinayak P.
Item Type: Refine your search to only Thesis or Dissertation
open access

Using a Multimodal Sensing Approach to Characterize Human Thermal Comfort Level

Description: A method to distinguish human level of comfort has been developed by using a thermal camera, physiological sensors, and a surroundings sensor. The method has successfully collected data from hominal facial features, breathing rate, skin temperature, room temperature, blood volume pressure, relative humidity, and air velocity. Participants from all genders and races were involved in two sessions of a human comfort experiment including a psychology survey session. The variables, such as room temp… more
Date: December 2013
Creator: Wicaksono, Cakra Aditya
Item Type: Refine your search to only Thesis or Dissertation
open access

Development of a Cost Effective Wireless Sensor System for Indoor Air Quality Monitoring Applications

Description: Poor air quality can greatly affect the public health. Research studies indicate that indoor air can be more polluted than the outdoor air. An indoor air quality monitoring system will help to create an awareness of the quality of air inside which will eventually help in improving it. The objective of this research is to develop a low cost wireless sensor system for indoor air quality monitoring. The major cost reduction of the system is achieved by using low priced sensors. Interface circuits … more
Date: May 2014
Creator: Abraham, Sherin
Item Type: Refine your search to only Thesis or Dissertation
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