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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Florida’s Recycled Water Footprint: A Geospatial Analysis of Distribution (2009 and 2015)

Archer, Jana E., Luffman, Ingrid E., Nandi, Arpita N., Joyner, T. Andrew 01 January 2019 (has links)
Water shortages resulting from increased demand or reduced supply may be addressed, in part, by redirecting recycled water for irrigation, industrial reuse, groundwater recharge, and as effluent discharge returned to streams. Recycled water is an essential component of integrated water management and broader adoption of recycled water will increase water conservation in water-stressed coastal communities. This study examined spatial patterns of recycled water use in Florida in 2009 and 2015 to detect gaps in distribution, quantify temporal change, and identify potential areas for expansion. Databases of recycled water products and distribution centers for Florida in 2009 and 2015 were developed by combining the 2008 and 2012 Clean Water Needs Survey databases with Florida’s 2009 and 2015 Reuse Inventory databases, respectively. Florida increased recycled water production from 674.85 mgd in 2009 to 738.15 mgd in 2015, an increase of 63.30 mgd. The increase was primarily allocated to use in public access areas, groundwater recharge, and industrial reuse, all within the South Florida Water Management District (WMD). In particular, Miami was identified in 2009 as an area of opportunity for recycled water development, and by 2015 it had increased production and reduced the production gap. Overall, South Florida WMD had the largest increase in production of 44.38 mgd (69%), while Southwest Florida WMD decreased production of recycled water by 1.68 mgd, or 3%. Overall increase in use of recycled water may be related to higher demand due to increased population coupled with public programs and policy changes that promote recycled water use at both the municipal and individual level.
172

Mejoramiento de las propiedades mecánicas de un suelo arcilloso de alta plasticidad del Caserío Bello Horizonte, distrito de Curimaná, departamento de Ucayali, adicionando pet reciclado

Alvarez Cabrera, Anthony Robert Jingary, Sosa Gonzales, Jose Antonio 29 September 2020 (has links)
Ante la problemática que presentan los suelos arcillosos de alta plasticidad, como la vulnerabilidad a variaciones de volumen, produciendo asentamientos diferenciales ocasionando daños en las estructuras, es por factores como este que se decidió buscar una alternativa de mejora para sus parámetros como el incremento de la resistencia, ángulo de fricción y cohesión de un suelo arcilloso de alta plasticidad (CH). En la ejecución de una obra civil, estos parámetros generalmente no se ajustan a los requerimientos del proyecto, por tal razón se debe buscar una solución para la estabilidad del suelo implicado en cualquier construcción. La constante búsqueda del mejoramiento de las condiciones ambientales ha llevado a la utilización de los residuos del plástico para reforzar el suelo y mejorar sus propiedades mecánicas y físicas. Es por ello que de acuerdo con nuestra propuesta se intenta incrementar data para el uso de este material alternativo como propuesta de mejoramiento del suelo, obteniéndose resultados interesantes y distintos a lo hallado en otras investigaciones que utilizaron similares materiales. Se optó por la trituración del tereftalato de polietileno (PET) obteniendo un PET reciclado de 3-5 mm de longitud como material de refuerzo para mejorar las propiedades mecánicas del suelo. De acuerdo con los ensayos de proctor estándar y corte directo, se determinó que el porcentaje óptimo de adición sea de 1% debido a que se observó un mejor comportamiento del material de estudio con respecto a las otras mezclas analizadas con 0.5%, 2.5% y 3.5%. / To the problems posed by clay soils of high plasticity, such as vulnerability to variations in volume, producing differential settlements causing damage to structures, it is due to factors such as this it was decided to seek an alternative enhancement to parameters such as increased resistance, friction angle and cohesion of a high plasticity clay soil (CH). In the execution of civil works, these parameters generally do not conform to the requirements of the project, for that reason should seek a solution for the stability of the soil involved in any construction. The constant search for improving environmental conditions has led to the use of waste plastic to reinforce the soil and improve its mechanical and physical properties. That is why according to our proposal we try to increase data for the use of this alternative material as a soil improvement proposal, obtaining interesting and different results to that found in other investigations that used similar materials. We chose crushing polyethylene terephthalate (PET) obtaining a recycled PET 3-5 mm length as a reinforcing material to stabilize and improve the mechanical properties of the soil. According to the standard proctor and direct shear tests, it was determined that the optimal percentage of addition is 1% because a better behavior of the study material was observed with respect to the other mixtures analyzed with 0.5%, 2.5% and 3.5%. / Tesis
173

La influencia del RAP en la resistencia estructural de un pavimento reciclado en frío para el proyecto de conservación vial de la carretera Binacional Mazocruz – Puente Internacional / The influence of RAP on the structural resistance of a cold recycled pavement for the road conservation Project of the Mazocruz Binational Road – International Bridge

Flores Falcón, Carla Sofía, Saldaña Núñez, Antuanet Yahaira 21 July 2020 (has links)
El Proyecto de “Mejoramiento de la carretera Dv. Humajalso-Desaguadero y Tacna-Tarata-Capazo-Mazocruz por niveles de servicio” se encuentra en los departamentos de Tacna, Puno y Moquegua, Perú. Este proyecto es ejecutado por el Consorcio Vial Santa Rosa. La presente tesis, ubicado en el proyecto en mención, desarrolla el estudio de la influencia el RAP en el paquete de pavimento que será reciclado en frío, consistiendo en el pavimento reciclado; en este caso, al pavimento de asfalto existente más la base granular existente. Por lo que, se plantea el análisis escenarios desde base cero para tener una línea guía de referencia con espesores típicos de reciclados de 15 cm, 20 cm y 25 cm; en donde, se analiza la variación de la influencia del RAP con una proporción de cemento que se le agrega de 1% y 2% para estudiar el comportamiento con ayuda del CBR y del número estructural perteneciente a la fórmula de AASHTO. Se planteará el diseño del pavimento con cemento por medio de AASHTO. Por último, se verá en los resultados la influencia negativa que tiene el RAP en la resistencia estructural y la proporción aproximada de decremento de esta y las recomendaciones del caso. / The Project of “Mejoramiento de la carretera Dv. Humajalso-Desaguadero y Tacna-Tarata-Capazo-Mazocruz por niveles de servicio” is located in the departments of Tacna, Puno and Moquegua, Perú. This project is executed by Consorcio Vial Santa Rosa. This thesis, located in the project in question, develops the study of the influence of the RAP on the pavement package that will be cold recycled, consisting of the recycled pavement; in this case, to the existing asphalt pavement plus the existing granular base. Therefore, it is proposed to analyze scenarios from scratch to have a reference guideline with typical recycled thicknesses of 15 cm, 20 cm and 25 cm; where, the variation of the influence of the RAP is analyzed with a proportion of cement added of 1% and 2% to analyze the behavior with the help of the CBR and the structural number belonging to the AASHTO formula. The design of the pavement with cement through AASHTO will be considered. Finally, the negative influence of the RAP on the structural strength and the approximate proportion of its decrease will be seen in the results and the recommendations of the case. / Tesis
174

Survival of <i>Mycoplasma</i> Species in Recycled Bedding Sand and Possible Implications for Disease Transmission to Ruminants

Justice-Allen, Anne E. 01 May 2010 (has links)
Mycoplasmas are a group of bacteria which are small in size, lack a cell wall, and have small genomes in comparison to other bacteria. The members of the group that are pathogenic utilize several mechanisms to evade the host's immune system. These processes affect surveillance and control mechanisms such as serologic testing and vaccination. Many of these organisms cause diseases of livestock, which heavily impact production parameters such as weight gain, milk yield, and egg production. Mycoplasmas also cause disease in people. Mycoplasma spp. can cause mastitis, metritis, pneumonia, and arthritis. The currently documented routes of transmission of Mycoplasma spp. are through fomites and by direct animal contact. The existence of environmental sources for Mycoplasma spp. and their role in transmission are poorly characterized. Mycoplasma spp. (confirmed as M. bovis using PCR) was found in recycled bedding sand from a dairy experiencing an outbreak of mycoplasma mastitis. The possibility of a persistent environmental source of Mycoplasma spp. in recycled bedding sand was further investigated using recycled sand from the dairy. Study objectives included determining factors associated with the persistence of Mycoplasma spp. in recycled bedding sand and the duration of survival of mycoplasmas in the sand. We also evaluated 2 disinfectants at 2 different concentrations each for the elimination of Mycoplasma spp. from contaminated sand. Mycoplasma spp. survived in the sand pile intermittently over a period of 8 months. The concentration of Mycoplasma spp. within the sand pile was directly related to temperature and precipitation. The survival of Mycoplasma spp. at a greater than expected range of temperatures suggests the formation of a biofilm. Ideal temperatures for replication of Mycoplasma spp. occurred between 15 °C and 20 °C. Moisture in the sand and movement of the sand pile also appeared to play a role in replication of mycoplasmas. Sodium hypochlorite (0.5%) and chlorhexidine (2%) were efficacious in eliminating Mycoplasma spp. from contaminated bedding sand. Recycled bedding sand could be an environmental source of Mycoplasma spp. infections, including M. bovis, in dairy cows. Future studies should investigate the contribution of this environmental source to the epidemiology of mycoplasma infections in dairy cattle and other ruminants.
175

Durability characteristics of asphalt mixtures containing bioditives

Hufft, Amanda 13 December 2019 (has links)
This thesis is focused on determining the durability characteristics of asphalt mixtures containing bio-based additives for the purpose of more effective use of recycled materials. Fifty mixtures were evaluated by Cantabro Mass Loss testing in their virgin state, after 1 year of field aging, and after laboratory conditioning to determine the effectiveness of bioditives in dense graded asphalt and sand asphalt mixtures. Key findings from this work demonstrated that considerable amounts of recycled asphalt shingles (i.e. 5% of the total mixture) significantly affect the brittleness of dense graded asphalt mixtures when used in conjunction with reclaimed asphalt pavement (RAP). Furthermore, brittleness was not improved with the use of bioditives at high dosages (e.g. greater than 7.5% of the total binder content), but was improved in some cases at lower dosage rates (e.g. 2.5-5%). Additional testing of similar mixtures and bioditives evaluated in this thesis are recommended.
176

Effect of Recycled Asphalt Shingles (RAS) on Physical and Chemical Properties of Asphalt Binders

Mannan, Umme Amina 31 August 2012 (has links)
No description available.
177

Development of Commercial Applications for Recycled Plastics Using Finite Element Analysis

Narasimhamurthy, Nanjunda 15 November 2005 (has links) (PDF)
This thesis investigates the suitability of thermo-kinetically recycled plastics for use in commercial product applications using finite element analysis and statistics. Different recycled material blends were tested and evaluated for their use in commercial product applications. There are six different blends of thermo-kinetically recycled plastics used for testing and CATIA is used for finite element analysis. The different types of thermo-kinetically recycled plastics blends are: pop bottles made of PolyethyleneTeraphthalate (PET), milk jugs made of High-Density Polyethylene (HDPE), Vinyl seats made of Poly Vinyl Chloride (PVC) and small amount of Polypropylene (PP) and Urethane, electronic scrap made of engineering resins like Acrylo-Nitrile-Butadiene Styrene (ABS), Polystyrene (PS) and Polycarbonate (PC), agriculture waste consisting of Low Density Polyethylene (LDPE), industrial waste consisting of Nylon (PA66) and PolyethyleneTeraphthalate (PET), household waste consisting of Polystyrene (PS). The methods employed during the study include three phases for each of six blends available: 1.Density, tensile and impact testing of each blend 2.Correlation of mechanical properties to blend 3.Finite element analysis of the service performance of a product made from each thermo-kinetically recycled plastic blend This thesis shows that some of the recycled plastics materials that were tested are qualified to be used in the pallet. Those materials that qualified were Industrial waste consisting of Nylon and PolyethyleneTeraphthalate, household waste consisting of Polystyrene.
178

Investigation on the Overall Performance of Recycled Concrete Affected by Alkali-Silica Reaction

Ziapourrazlighi, Rouzbeh 17 April 2023 (has links)
Pressure is mounting in the concrete industry to adopt eco-efficient methods to reduce CO₂ emissions. Portland cement (PC), an essential concrete ingredient, is responsible for over two-thirds of the embodied energy of the concrete, generating about 8% of global greenhouse gas emissions. Extraction and transportation of aggregates and raw materials that comprise concrete mixes are also directly linked to their embodied energy; thus, recycled concrete aggregates (RCA) have been proposed as a promising alternative to increase sustainability in new construction. In this context, many studies have been conducted over the past decades on the properties of RCA concrete. Recent studies have shown that suitable fresh (i.e., flowability) and short-term hardened (i.e., compressive strength) properties might be achieved when the unique microstructural features of RCA are accounted for in the mix-design process of the recycled concrete. However, manufacturing RCA from construction demolition waste (CDW) or returned concrete (RC) presents its unique challenges. Amongst others, the variation in the source of RCA and the presence of damage due to several deterioration mechanisms causes major concern. Due to the presence of reactive aggregates in many quarries in Canada, alkali-silica reaction (ASR) is one of the most common deterioration mechanisms. The durability and long-term performance of RCA concrete are not fully understood and should be further investigated, especially in regards to a) the potential of further (secondary) deterioration of recycled concrete bearing coarse and fine alkali-silica reactive aggregates b) the impact of the severity of the initial reaction on mechanical properties and kinetics of expansion in recycled concrete and c) the impact of using sound and alkali-silica reaction (ASR) affected RCA on the chloride diffusivity (and thus corrosion initiation) of concrete. This work aims to appraise the durability performance of RCA concrete made of 100% coarse RCA, particularly two families of RCA selected (i.e., returned concrete RCA, demolished concrete RCA) to represent waste currently being generated. Furthermore, two types of reactive aggregates are selected to investigate the impact of the source of the reaction (i.e. reactive coarse aggregate as original virgin aggregate - OVA and reactive sand within the residual mortar - RM) within the RCA. ASR is the distress mechanism used to introduce damage to the manufactured RCA. A new mix design technique was used to produce recycled concrete mixtures to increase eco-efficiency, improve fresh-state properties, and reduce cement use in RCA concrete. In conclusion, the initial reaction's location and severity significantly impact the compressive strength, SDT parameters, chloride diffusion rate, and shear strength of concrete specimens. Specifically, the location of the initial reaction can influence the distribution and extension of damage within the various parts of recycled concrete, while the severity of the initial reaction can affect the overall integrity of the aggregates as well as the availability of silica and alkalis for secondary reaction. These results demonstrate the importance of assessing the severity of the initial reaction and its source in order to ensure the durability and long-term performance of recycled concrete made with reactive RCA.
179

Evaluating The Use Of Recycled Concrete Aggregate In French Drain Applications

Behring, Zachary 01 January 2013 (has links)
Recycled concrete aggregate (RCA) is often used as a replacement of virgin aggregate in road foundations (base course), embankments, hot-mix asphalt, and Portland cement concrete. However, the use of RCA in exfiltration drainage systems, such as French drains, is currently prohibited in many states of the U.S. The French drain system collects water runoff from the road pavement and transfers to slotted pipes underground and then filters through coarse aggregate and geotextile. The primary concerns with using RCA as a drainage media are the fines content and the precipitation of calcium carbonate to cause a reducing in filter fabric permittivity. Additional concerns include the potential for rehydration of RCA fines. The performance of RCA as drainage material has not been evaluated by many researchers and the limited information limits its use. A literature review has been conducted on the available information related to RCA as drainage material. A survey was issued to the Departments of Transportation across the nation in regards to using RCA particularly in French drains. Some state highway agencies have reported the use of RCA as base course; however, no state reports the use of RCA in exfiltration drainage systems. This thesis describes the investigations on the performance of RCA as backfill material in French drains. RCA was tested for its physical properties including, specific gravity, unit weight, percent voids, absorption, and abrasion resistance. RCA cleaning/washing methods were also applied to evaluate the fines removal processes. The potential for RCA rehydration was iv evaluated by means of heat of hydration, pH, compressive strength, and setting time. The permeability of RCA was tested using the No. 4 gradation. Long term permeability testing was conducted to evaluate the tendency for geotextile clogging from RCA fines. Calcium carbonate precipitation was also evaluated and a procedure to accelerate the precipitation process was developed. The results show that RCA has a high abrasion value, that is, it is very susceptible to break down from abrasion during aggregate handling such as transportation, stockpiling, or placing. The most effective cleaning method was found to be pressure washing with agitation. RCA has not demonstrated the tendency to rehydrate and harden when mixed with water. The permeability test results show that the No. 4 gradation does not restrict the flow of water; the flow rate is highly dependent on the hydraulic system itself, however excessive fines can cause large reductions in permeability over time. It has been determined that No. 4 gradation of RCA can provide a suitable drainage media providing the RCA is properly treated before its use.
180

Effects of Recycled Water on Landscape Plants

Miranda, Casey R 01 June 2010 (has links) (PDF)
ABSTRACT EFFECTS OF RECYCLED WATER ON LANDSCAPE PLANTS Casey Ray Miranda Recycled water is water that has been previously used, has suffered a loss of quality, and has been properly treated for redistribution (Wu et al. 2001). The use of recycled water as an alternative to fresh water in the landscape can have positive and negative effects. Experimentation on 40 different plant species during a 32 week period (2 phases of 16 weeks), was conducted to analyze the effects of recycled water irrigation on the appearance of landscape plants. Each species of plant was planted into 10 individual number 2 pots and irrigated with recycled water daily. Media and water were tested for nutrients and other constituents. In phase I there were four different species of grasses and grass-like plants, five different perennials, five species of shrubs, and four annuals tested; while phase II tested four species of herbaceous perennials, eight different species of shrubs, six species of groundcovers, and four species of annuals. All tests were conducted at the Paso Robles Waste Water Treatment Plant. Of the grasses and grass like species Yucca spp. and Buchloe spp. performed best. Osteospermum fruticosum, Lavandula angustifolia, Rosmarinus officinalis, Phormium tenax, and Pennisetum setaceum had the best appearance of the herbaceous perennials tested. For the shrubs, Coprosma repens, Cistus purpureus, Dodonea viscosa, Eleagnus pungens, Baccharis pilularis, Ceanothus thysiflorus, Thuja orientalis, and Nerium oleander had the best appearance when irrigated with recycled water. The best annuals were Senecio cineraria, Antirrhinum majus, Primula spp., Viola spp., and Calendula officinalis. Of the groundcovers Heuchera spp., Lonicera japonica, Vinca major, Hedera helix, and Ceanothus griseus had the best results. From the experiment a list of tolerant and non-tolerant plants was compiled (Appendices 1 and 2). While many plants were capable of developing and growing normally, other plants were sensitive to recycled water irrigation. In order to prevent salt damage to plants and expand the use of recycled water, salt tolerance of landscape plant material must be identified (Niu et.al, 2006).

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