Browsing by Subject "Recycling"
Now showing 1 - 9 of 9
Results Per Page
Sort Options
Item An alternative environmentally benign process for printed circuit board recycling(Texas Tech University, 2006-05) Ouyang, Xi; Zhang, Hong-Chao; Li, Guigen; Rivero, Iris V.; Smith, Milton L.; Collins, Terry R.In recent years there has been increasing concern about the growing volume of end-of-life electronic products. As the primary elements in most electronic products, Printed Circuit Board (PCB) is widely used and its recycling becomes a challenge not only to the industry, but also to the society. As an alternative environmentally benign method for PCB recycling, this dissertation adopts a novel processing method to separate the PCB scraps, which would increase the recycling rate and reduce the negative environment impact. Various solvent systems, i.e., carbon dioxide and water, are explored for delaminating PCB scraps at certain high temperature and pressure. For the purpose of finding an optimal condition for PCB delaminating, the experiment facilities were set up at the Advanced Manufacturing Lab (AML) in the Department of Industrial Engineering. Through series designed experiments, input parameters such as temperature, pressure and process time were recorded, and the output parameters, i.e., weight reduction, thickness expansion, impact energy variation were measured to evaluate the PCB delaminating results. Response Surface Method (RSM) was applied for selecting the input parameters. Multiple Objective Optimization method (MOO) was adopted to evaluate the overall delaminating effects. The utility theory was utilized to set up the utility function and figure out the optimal solution. Furthermore, the fundamental mechanism which caused the epoxy resin decomposing was interpreted. The explanation was helpful for selecting various solvents to speed up the reaction and improve the efficiency. In this research, the effectiveness of the alternative method to delaminate waste PCB scraps, that is, utilization of the chemical process was examined. Based on this method, series experiments were designed and implemented to search for an optimal condition. Through the output data analysis, optimization process conditions were determined. Consequently the reaction mechanism was interpreted. Some other solvent systems were tested to hasten the reaction speed, i.e., ternary solvent system of carbon dioxide, water, and ethanol. This alternative printed circuit board recycling process is promising for industrialization in the future.Item An alternative environmentally benign process for printed circuit board recycling(2006-05) Ouyang, Xi; Zhang, Hong-Chao; Collins, Terry R.; Li, Guigen; Rivero, Iris V.; Smith, Milton L.In recent years there has been increasing concern about the growing volume of end-of-life electronic products. As the primary elements in most electronic products, Printed Circuit Board (PCB) is widely used and its recycling becomes a challenge not only to the industry, but also to the society. As an alternative environmentally benign method for PCB recycling, this dissertation adopts a novel processing method to separate the PCB scraps, which would increase the recycling rate and reduce the negative environment impact. Various solvent systems, i.e., carbon dioxide and water, are explored for delaminating PCB scraps at certain high temperature and pressure. For the purpose of finding an optimal condition for PCB delaminating, the experiment facilities were set up at the Advanced Manufacturing Lab (AML) in the Department of Industrial Engineering. Through series designed experiments, input parameters such as temperature, pressure and process time were recorded, and the output parameters, i.e., weight reduction, thickness expansion, impact energy variation were measured to evaluate the PCB delaminating results. Response Surface Method (RSM) was applied for selecting the input parameters. Multiple Objective Optimization method (MOO) was adopted to evaluate the overall delaminating effects. The utility theory was utilized to set up the utility function and figure out the optimal solution. Furthermore, the fundamental mechanism which caused the epoxy resin decomposing was interpreted. The explanation was helpful for selecting various solvents to speed up the reaction and improve the efficiency. In this research, the effectiveness of the alternative method to delaminate waste PCB scraps, that is, utilization of the chemical process was examined. Based on this method, series experiments were designed and implemented to search for an optimal condition. Through the output data analysis, optimization process conditions were determined. Consequently the reaction mechanism was interpreted. Some other solvent systems were tested to hasten the reaction speed, i.e., ternary solvent system of carbon dioxide, water, and ethanol. This alternative printed circuit board recycling process is promising for industrialization in the future.Item Fresh water reduction technologies and strategies for hydraulic fracturing : case study of the Eagle Ford shale play, Texas(2013-12) Leseberg, Megan Patrice; Fisher, W. L. (William Lawrence), 1932-; Nicot, Jean-Philippe, 1958-Hydraulic fracturing has unlocked a tremendous resource across the United States and around the world—shale. However, these processes have also come with a myriad of potential environmental effects, including a substantial demand for water. Hydraulic fracturing can require anywhere between two and four million gallons per well. The need for such large quantities of water can produce severe stresses on local water resources. In response to this issue, operators have developed several ways to alleviate some of the stresses brought on by the extensive water use such as alternative sourcing and reuse technologies. Companies are driven to exercise these options and decrease their fresh water usage for hydraulic fracturing processes for multiple reasons, including changes in regulation, to gain support of local communities, and to increase efficiencies of operations. Whatever the motivation may be, there are a variety of options companies have at their disposal to reduce fresh water demands—dependent on specific formation characteristics, the qualities and quantities of available water, among others. The Eagle Ford shale is one of the most rapidly growing shale plays in the country. However, this formation is located in a fairly arid part of the country. Because of meager average rainfall totals, water availability to meet demand is an issue of great concern. Due to nearly exponential increases in shale production, stresses on local water supplies have dramatically increased as well. The objectives of this thesis are as follows: 1) to establish the enormous resource that has become available; while still recognizing the environmental impacts associated with development processes, focusing primarily on water requirements and associated wastewater production; 2) to break down current water demand for shale development, as well as wastewater management practices in the Eagle Ford, with a brief comparison to other shale plays across the country; 3) to obtain an understanding of operator motivation—what factors affect wastewater management strategies; and 4) to analyze techniques operators presently have at their disposal to reduce fresh water demands, specifically through the use of brackish waters and recycling/reuse efforts, and finally to quantify these efforts to evaluate potential fresh water savings.Item Public space recycling : the study of a Capital Metro pilot program for transit stop recycling(2014-12) Larrick, Alden Hall; Moore, Steven A., 1945-Over the course of the last several decades, an increase in the level of concern surrounding the various health and environmental consequences of current, popular waste disposal methods, including landfilling and incineration, have resulted in an increase in municipal recycling efforts. These efforts take place primarily at the residential and commercial levels, while the availability of recycling in public spaces like sidewalks, transit stops, parks and other areas is not something that is often encountered in cities around the United States. This thesis studies the implications and opportunities for public space recycling through the action research process during which I conducted case study research of existing public space recycling programs in Portland, Oregon, and New York, New York, alongside the planning and implementation of a pilot program for transit stop recycling in Austin, Texas. The aim of this thesis is to examine and establish various goals and common strategies for the implementation of public space recycling programs and ultimately make a case for this arguably invaluable, yet often overlooked, recycling initiative. Working under the theoretical framework of the urban metabolism and Karl Marx’s theory of the metabolic rift, the reimagining of waste disposal practices to include widespread materials recycling is one avenue for the restructuring of the relationship between the city and the natural environment. The expansion of recycling practices into public spaces forwards the overall mission to make recycling an integral part of daily life. If implemented properly, the widespread implementation of recycling programs like public space recycling could begin to heal the fragmented urban metabolism and ensure the longevity of the ever-evolving urban and natural environments. The conclusions of this research revolve around the importance of context for public space (and other) recycling practices. This research shows that for public space recycling to succeed as a strategy for the mainstreaming of recycling practices and the reparation of the metabolic rift, the unique characteristics of each individual public space must be taken into consideration upon the implementation of a public space recycling program.Item Quantity and quality of runoff from two biosolids-amended Chihuahuan Desert grassland soils(Texas Tech University, 1997-05) Moffet, Corey AllenWater is a precious resource in the arid west. Communities, both plant and animal, depend on it for basic life functions. Land application of biosoHds on arid and semi-arid rangeland has led to growing interest in determining the hydrologic consequences of this practice. Water, in the form of precipitation, is partitioned into runoff, interception, or infiltration at the active surface. Because the application of biosolids alters the active surface it may be expected that biosolids also will affect infiltration, runoff and erosion. The objectives of this work were to: (1) evaluate the effects of varied rates of biosolids on infiltration, and erosion; (2) examine some of the mechanisms whereby biosolids application affect infiltration and erosion; and (3) find environmental conditions that maximize or minimize the response of infiltration or erosion to biosolids application. A portable single-nozzle rainfall simulator was used to simulate rainfall on 0.5 m^ plots to determine infiltration and erosion. Many factors are considered including soil type; season of simulation; the period of time biosolids are in plots before simulation; vegetative cover: the rate of biosolids applied; and antecedent soil water. Measurements recorded to characterize each plot included canopy cover, surface cover, surface roughness, plot standing crop and liter, and soil morphology to 35 cm depth. Experimentally manipulated factors included soil type, vegetation cover, rate of biosolids applied, and antecedent soil water. Application of biosolids affects infiltration rate, cumulative infiltration and erosion. Biosolids provides ground cover and adds organic matter to the soil. The hydrologic response to biosolids depends on site factors, including soil type and cover and biosolids factors such as rate and batch. Topical application of biosolids has important hydrologic consequences in desert grasslands that depend upon the rate of biosolids applied and is modified by the environment to which the biosolids are applied.Item Recycling behavior in the home environment: A comparative approach between Daegu, South Korea and Lubbock, Texas, United States(2009-05) Jurng, Youjin; Amor, Cherif; Curry, Zane D.; Shroyer, Jo Ann L.In 2005, Americans generated about 245.7 million tons of solid waste (USEPA, 2008). Hattam (2005) mentioned that only 30% of the waste is recycled and most trash is produced from households. Oskamp et al. (1991) suggested that one vital method to reduce solid waste is recycling in the household. Thus, interior designers can play a vital role of increasing recycling by designing areas for recycling in homes. The purpose of this research is to first, investigate the readiness to recycle in the home environment, and second, design an appropriate location for bins for recycling to promote recycling behavior, and finally, identify an appropriate design for bins for recycling to also promote recycling behavior. The intention of comparing two cultures is to evaluate recycling behavior in the home environment from two distinct settings to understand the reasons why people’s behaviors towards recycling are different. The results will help designers implement recycling in homes and create a recycling environment within the community. A quantitative research approach was used in this investigation to identify how people perceive the idea of recycling in their homes in two different cities, Daegu, South Korea and Lubbock, Texas, United States. A total sample of 200, which consists of 100 samples from Daegu and 100 samples from Lubbock were used. The questionnaire for this study was developed to research how people perceive the idea of recycling in their homes in order to determine the most convenient area to place bins for recycling in homes and the design of the recycling bin to promote recycling behavior. The responses were then analyzed using frequency distribution, analysis, percentages, bivariate correlations, and ANOVA using SPSS Statistical Package. Some results and correlations between the two cities corresponded to one another and some differed. Conclusions were examined with the determinants of household waste recycling as outlined in the literature review. Other correlations were also formulated to understand the relationship between recycling behavior and categories including socio-demographics, psychological aspects of recycling behavior, recycling activity, and location and design of recycling bin. This study demonstrated the readiness of individuals to recycle in the home environment as many factors directly corresponded to recycling behavior. Also, the comparison of the two cities supported that the determinants of household recycling behavior are closely congruent multi-nationally. In addition, the study of two distinct cultures clearly portrayed that the location for bins for recycling is distinct and clear for each culture as it relates to their home environment. Overall, the results of this study have proven to be valuable, but limitations exist as these samples cannot be used to generalize the entire South Korean and American culture. Even so, the outcome of this study can be used for future research activities that investigate how the determinants of household recycling behavior identified in this study relate to household recycling behaviors in other cultures.Item The recyclists : bikes, borders and basura(2009-12) Melanson, Michael P., 1978-; Dahlby, Tracy; Minutaglio, Bill; Cash, WandaIn January, 2009, I joined Bikes Across Borders, a local grassroots organization, on their yearly bike caravan to Mexico. The group works to promote bicycles, both here and in Mexico, as an environmentally and financially sound alternative to motorized transportation. Each winter, members ride bicycles they build out of salvaged parts to border cities in Mexico. They give these bicycles to maquiladora workers who would otherwise spend a large portion of their income on transportation. These workers make a fraction of what they would in the U.S. and live in shacks amid the pollution from the factories they work in. This is the story of one group’s attempt at making a difference in the lives of these workers.Item The Copolymerization of CO_(2) and Cyclic Ethers and Their Degradation Pathways(2013-07-24) Wei, Sheng-HsuanPolycarbonates are found in a variety of common products in daily life due to their favorable mechanical and electrical properties. In addition, they are widely used in biomedical areas due to their stability and biological inertness. Therefore, the production of polycarbonates became an important industrial process in the past decades. However, the current industrial process usually requires toxic phosgene gas as a starting material. Thus, the environmentally benign route by using metal catalyzed couplings of epoxides and CO_(2) to produce polycarbonates has received attention from researchers. In this dissertation, metal catalyzed CO_(2)/cyclic ether copolymerization, depolymerization of polycarbonates, and the equilibria between polycarbonate and corresponding six-membered cyclic carbonate will be investigated. First, the Co(III) catalyzed copolymerizations of CO_(2) and various epoxides with electron-withdrawing substituents to afford polycarbonates are examined. Comparative kinetic studies were performed via in situ infrared measurements as a function of temperature to assess the activation barriers for the production of cyclic carbonate versus copolymer involving electronically different epoxides: styrene oxide, epichlorohydrin, and propylene oxide. Thermodynamically stable cyclic carbonate byproducts are produced during the course of the reaction from the degradations of propagating polymer chains. The depolymerization reactions of several polycarbonates produced from the completely alternating copolymerization of styrene oxide, epichlorohydrin, propylene oxide, cyclohexene oxide, indene oxide, and cyclopentene oxide with carbon dioxide have been investigated. Various reaction pathways can be found under different reaction conditions, including process involving chain-end backbiting and radical intermediates. Temperature-dependent kinetic studies have provided energy of activation barriers for cyclic carbonate formation. In addition, the generated monomeric materials from the degradation of select polycarbonates show the possibility of chemical recycling of plastic waste. For the copolymers made from CO_(2) and oxetane derivatives, this study focuses on the influence of steric hindrance in the 3-position of the monomer oxetane. The (salen)CrCl/onium salt catalyzed coupling reactions of these oxetane derivatives and carbon dioxide are reported. Depolymerizations of copolymers to their corresponding cyclic carbonates were also studied. In addition, several six-membered cyclic carbonates were synthesized to examine their equilibria between monomeric cyclic carbonates and their corresponding polycarbonates.Item The research and development of an air separation conveyor for obsolete electronic products recycling(Texas Tech University, 2003-05) Campbell, John SElectronics are a rapidly evolving industry with continuous development of new and progressive technology. The ceaseless flux of high-technology products into the marketplace is creating a serious environmental dilemma. Most electronic components contain a significant amount or material reources which have the potential to be recovered but instead are stored indefinitely or are dumped in landfills. Research and development in the electronics recycling industry must keep pace with electronics manufacturers if we are to avert a major environmental crisis. In this thesis, a new separation process was developed and a prototype unit constructed. The machine described in this paper illustrates yet another method of material separation in the electronics recycling industry. Continued research and development in recycling technology is essential to ensure that the very electronics we seek today are not the same ones which bring on the environmental demise of tomorrow.