• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 40
  • 19
  • 18
  • 8
  • 4
  • 4
  • 2
  • 2
  • 1
  • Tagged with
  • 127
  • 68
  • 52
  • 36
  • 35
  • 34
  • 27
  • 25
  • 25
  • 18
  • 18
  • 17
  • 13
  • 12
  • 12
  • 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.
61

Effektivisering av lastningsprocessen : En jämförelseanalys av alternativa lastningsmetoder

Mahmood, Ahmed, Abdullahi, Badder January 2020 (has links)
Background Loading efficiency within logistics is a research area which has been given a lot of attention by researchers during recent years. Pallet Loading Problem has been presented as a mean to tackle the loading efficiency issue in this area. Loading efficiency can be measured in terms of fill rate of the load and the number of reclaimed gods. Different loading methods presents advantages and disadvantages regarding the two presented areas fill rate and returned gods.      Purpose The purpose with this study is to examine the different issues related to implementing an efficient pallet loading method, with the help of a comparative study of alternative loading methods. In order to accomplish this, different key factors are located and identified in which the relation between these factors is displayed. Research in this area has highlighted that a streamlining of the loading process has assisted organizations in reducing their costs. The cost reduction is an effect of the reduced transport and reclaimed gods.   Methods In this comparative study of alternative loading methods, key factors in different loading methods were identified and analyzed. The data for the three key factors were collected through archival research, unstructured interviews and observations of the different procedures. The analytic tests of the data where conducted through SPSS with the likes of descriptive statistic, non-parametric t-test, correlation and logistic regression.     Results In the result of this thesis, the differences of studied loading methods are presented based on the defined key factors. Each loading method is individually analysed and later compared to the other alternative loading method in order to decide which method is the most efficient, based on the presented key factors. The analyses in the tests presents a connection between fill rate and claims but also between claims and loading method.     Conclusions Between the two presented loading methods, free pallet loading and standing pallet loading, there’s a significant difference based on the analysed key factors. Free pallet loading is concluded to be the more efficient loading method in each of the analysed categories fill rate, claims and cost of claims. This concludes free pallet loading to be the more sustainable and economically beneficial loading method. / Bakgrund Lastningseffektivitet inom logistiken är ett område som dem senaste år fått mycket uppmärksamhet där pallastning av produkter är ett centralt område. En lastningseffektivitet kan mätas i den totala fyllnadsgraden för lastningen samt vilken skaderisk det medför. Två centrala begrepp vilka studerats för lastning är Pallet Loading Problem samt Reclaimed Gods.            Ovanstående ämnesområden presenterar fördelar samt nackdelar med olika lastningsmetoder.   Syfte Syftet med denna studie är att undersöka problematiken kring att tillämpa en effektiv pallastning med hjälp av en jämförelsestudie kring alternativa lastningsmetoder. Detta då för att identifiera och kartlägga nyckelfaktorer samt sambandet mellan dessa i en lastningsprocess. Forskning visar på att en effektivisering av lastningsprocessen har hjälpt olika företag att reducera sina kostnader, genom en minskning av transport samt minimering av skaderisk för det lastade godset.   Metod Tillvägagångssättet för denna studie var att göra en jämförelsestudie där nyckelfaktorer i olika lastningsmetoder skall analyseras. Tre olika faktorer för lastning analyserades, där underlag för analysen införskaffades ur organisationens datasamling genom arkivforskning, observationer samt ostrukturerade intervjuer. Analyserna gjordes i SPSS genom de olika dataanalystesterna, deskriptiv statistik, icke parametriskt t-test, korrelation samt logistisk regression.   Resultat Resultatet av studien visar hur lastning skiljer sig åt med avseende på de tre olika nyckelkoncepten beroende på vilken metod som ligger till grund. Respektive lastningsmetod analyseras för sig själv för att sedan jämföras, detta då för att identifiera vilken som är effektivast beroende på nyckelfaktorer. Resultatet presenterar ett samband mellan claims och fyllnadsgraden samt mellan claims och metodval.    Slutsats Slutsatsen av denna studie är att bland de två presenterade lastningsmetoderna, löst liggande samt stående pallastning finns en signifikant skillnad sett till nyckelfaktorerna vilka undersökts. Löst liggande pallastning är en effektivare modell sett till samtliga av de undersökta nyckelfaktorerna det vill säga fyllnadsgrad, claims samt kostnaden vilken uppkommer i samband med claims. Detta medför att löst liggande lastning är den mer gynnsamma lastmetoden sett till både ett hållbarhets och ekonomiskt perspektiv.
62

Plant communities on reclaimed surface mines in Northeast Ohio: Effects of succession and nitrogen-fixing autumn olive

Ruggles, Thomas Alan 25 November 2019 (has links)
No description available.
63

Recyklace asfaltových pojiv pomocí oživovacích přísad / Recycling of bituminous binders by using recycling agents

Koudelka, Tomáš Unknown Date (has links)
Increasing the content of Reclaimed Asphalt in hot asphalt mixtures is one of the current issues in road construction, to which society's attention is paid. The higher content of Reclaimed Asphalt brings higher technological demands not only for the production of asphalt mixture plants, but also for the handling of materials in general. The benefit for higher demands on asphalt mixture production is the subsequent reduction of the environmental burden associated with the construction of road infrastructure caused by the mining industry and use of natural resources. The dissertation is focused on studying recycling agents which are used in the production of asphalt mixtures containing Reclaimed Asphalt. Emphasis is put on comparing the properties of recycled binders with paving bitumen and binders from Reclaimed Asphalts whereas the effect of repeated recycling is taken into account. A large part of the thesis is devoted to the design of the optimal dosage of recycling agents. Certain findings were used to draw a methodology describing the design of dosing of these agents. At the same time, the properties and behaviour of the recycling agents themselves were evaluated.
64

Cement Stabilization of Aggregate Base Materials Blended with Reclaimed Asphalt Pavement

Brown, Ashley Vannoy 12 May 2006 (has links) (PDF)
The purpose of this research was to investigate the effects of reclaimed asphalt pavement (RAP) content and cement content on the strength and durability of recycled aggregate base materials. Specifically, the unconfined compressive strength (UCS) and final dielectric value in the Tube Suction Test (TST) were measured in a full-factorial experimental design including five RAP contents, five cement contents, and three replicate specimens of each possible treatment. Specimen mixtures consisted of 0, 25, 50, 75, or 100 percent RAP and 0.0, 0.5, 1.0, 1.5, or 2.0 percent Type I/II Portland cement. Both the RAP and base materials were sampled from the I-84 pavement reconstruction project performed in Weber Canyon near Morgan, Utah, during the summers of 2004 and 2005. The laboratory testing procedures consisted of material characterizations, specimen preparation, and subjection of the specimens to strength and durability testing, and the data were evaluated using analysis of variance (ANOVA) testing. Both the RAP and base materials included in this research were determined to be non-plastic, and the AASHTO and Unified soil classifications for the RAP material were determined to be A-1-a and SM (well-graded sand with gravel), respectively, and for the base material they were A-1-a and SW-SM (well-graded sand with silt and gravel), respectively. The optimum moisture contents (OMCs) for the blended materials were between 5.6 and 6.6 percent, and maximum dry density (MDD) values were between 129.7 and 135.5 lb/ft3. In both cases, decreasing values were associated with increasing RAP contents. The results of the ANOVA performed on the UCS data indicate that UCS decreases from 425 to 208 psi as RAP content increases from 0 to 100 percent and increases from 63 to 564 psi as cement content increases from 0.0 to 2.0 percent. Similarly, the final dielectric value decreases from 14.9 to 6.1 as RAP content increases from 0 to 100 percent and decreases from 14.0 to 5.8 as cement content increases from 0.0 to 2.0 percent. With design criteria requiring 7-day UCS values between 300 and 400 psi and final dielectric values less than 10 in the TST, the results of this research suggest that milling plans should be utilized to achieve RAP contents in the range of 50 to 75 percent, and a cement content of 1.0 percent should be specified for this material. Cement contents less than 1.0 percent are not sufficient to stabilize the material, and greater cement contents may cause cracking. Because control of the actual cement content in the field depends on the contractor's equipment and skill, inspection protocols should be implemented during construction to ensure high-quality work. Additional recommendations are associated with the construction process. The specimens prepared in this research were compacted to relative densities of 100 percent using modified Proctor energy. Therefore, field compaction levels must approach these density values if the same material properties are to be achieved. In addition, all specimens tested in this study were cured at 100 percent relative humidity. Following compaction in the field, cement-treated layers should be moistened frequently during the first few days after construction or promptly sealed with a prime coat or wearing surface to ensure that the cement continues to hydrate. Variability in RAP and cement contents should also be minimized to achieve consistent material properties.
65

Evaluation of Full-depth Reclamation on Strength and Durability of Pavement Base Layers

Griggs, Benjamin Earl 24 March 2009 (has links) (PDF)
The purpose of this research was to determine the effect of full-depth reclamation (FDR) on the strength and durability of aggregate base layers in a coordinated approach involving both field and laboratory testing. Field comparisons between the pre-reclamation neat base and post-reclamation blended base were supplemented with laboratory experiments conducted to determine the effects of reclaimed asphalt pavement (RAP) content, compaction effort, and heating on the strength and durability of roadways reconstructed using FDR with a portable asphalt recycling machine (PARM). Also, the effect of reclamation on the spatial uniformity of the pavement structures was explored by comparing variability in the pre- and post-reclamation material properties. Test sites in Orem, Utah; San Marcos, Texas; and South Jordan, Utah, were selected for this research. The results of field testing indicate that the FDR process significantly increased the stiffness and/or strength of the base material at two of the test locations and did not significantly change the third base material. An evaluation of spatial variability indicated that the FDR process produced equivalent or lower spatial variability with respect to both base modulus and California bearing ratio (CBR) values at one site, while the other two sites exhibited equivalent or higher spatial variability after FDR. The results of laboratory testing for all three locations indicate that specimens compacted using the modified Proctor method exhibit significantly higher CBR values and dry densities than specimens compacted using the standard Proctor method. Also, the CBR values for specimens tested in the dry condition were significantly higher than those obtained from specimens tested at optimum moisture content. These results demonstrate the value of achieving a high level of compaction during construction and preventing water ingress into the pavement over time. The blended material exhibited a significantly lower CBR value than that of the neat material at only one location; the addition of RAP to materials at the other locations did not significantly change the CBR values of those materials. In the tube suction test (TST), most of the specimens were classified as marginally or highly moisture-susceptible, and the effect of RAP on the dielectric value in the TST was of no practical importance. The use of PARMs in the FDR process is an acceptable, economical, and environmentally friendly approach to reconstruction of flexible pavements. To ensure satisfactory performance of FDR projects, engineers and managers should carefully follow recommended guidelines for project selection, pavement testing, material characterization, design, construction, and quality assurance testing.
66

Effect of High Percentages of Reclaimed Asphalt Pavement on Mechanical Properties of Cement-Treated Base Material

Tolbert, Jacob Clark 10 July 2014 (has links) (PDF)
Full-depth reclamation (FDR) is an increasingly common technique that is used to rehabilitate flexible pavements. Implementation of FDR on rehabilitation projects produces several desirable benefits. However, these benefits are not fully realized due to the fact that state department of transportation specifications typically limit the reclaimed asphalt pavement (RAP) content of pavement base material to 50 percent. The objective of this research was to evaluate the effects of RAP content, cement content, temperature, curing time, curing condition, and moisture state on the strength, stiffness, and deformation characteristics of cement-treated base (CTB) mixtures containing high percentages of RAP.For this research, one aggregate base material and one RAP material were used for all samples. RAP content ranged from 0 to 100 percent in increments of 25 percent, and low, medium, and high cement levels corresponding to 7-day unconfined compressive strength (UCS) values of 200, 400, and 600 psi, respectively, were selected for testing. Moisture-density, UCS, resilient modulus, and permanent deformation tests were performed for various combinations of factors, and several statistical analyses were utilized to evaluate the results of the UCS, resilient modulus, and permanent deformation testing.The results of this work show that CTB containing RAP can be made to achieve 7-day UCS values approaching 600 psi regardless of RAP content. With regards to stiffness, the data collected in this study indicate that the resilient modulus of CTB containing RAP is affected by temperature in the range from 72 to 140°F for the low cement level. Permanent deformation of CTB containing RAP is significantly affected by RAP content and cement level at the test temperature of 140°F. At the low cement level, temperature is also a significant variable. As the 7-day UCS reaches approximately 400 psi, permanent deformation is reduced to negligible quantities. The results of this research indicate that the inverse relationship observed between permanent deformation and 7-day UCS is statistically significant.Given that the principle conclusion from this work is that CTB with high RAP contents can perform satisfactorily as a base material when a sufficient amount of cement is applied, agencies currently specifying limits on the percentage of RAP that can be used as a part of reclaimed base material in the FDR process should reevaluate their policies and specifications with the goal of allowing the use of high RAP contents where appropriate.
67

Comparison of Long-Term Recovery Between Managed and Unmanaged Reclaimed Mine Lands

Macy, Taylor 29 August 2014 (has links)
No description available.
68

hiResilient response and performance of bitumen stabilized materials with foam incorporating reclaimed asphalt

Dal Ben, Matteo 04 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The increased use of reclaimed asphalt (RA) in Bitumen Stabilised Materials (BSMs), shortcomings in the existing design guidelines and manuals and ongoing developments in the concepts and understanding of these materials require further research into the fundamental properties and behaviour of BSMs. The state-of-the-art of foamed bitumen techniques is reviewed in the literature study. Current best practices in the design of BSMs and pavements incorporating such materials are also included in this literature study. Shortcomings and areas for further improvement of the design practice have been identified. With new environmental legislation, the importance of BSM technology including RA as an environmentally-friendlier and more sustainable construction technique is set to increase in the coming years. Changes in the behaviour of materials and failure mechanisms of BSM mixes are long-term phenomena. This implies that the study of the physico-chemical and mechanical properties of the mixes with increasing amount of RA is vital. Therefore, fundamental understandings of moisture damage and thermo-physical characteristics, which are related to material properties, are required. The main objective of this study is to advance BSM technology by assessing the influence of the selected materials on durability behaviour, temperature distribution and long-term performance in all phases of application (i.e. mix design, construction, and in-service condition). This study begins with a comprehensive literature review of research dealing with the interactions between RA and mineral aggregates. The properties of RA and mineral aggregates were reviewed. This was followed by a review into the mechanical properties of BSM-foam mixes with high percentage of RA and its durability performance. Factors influencing the temperature gradient of BSMs were then identified. Achieving a better understanding of the fundamental performance properties and temperature influence on the behaviour of BSMs with high percentage of RA is one of the key factors of this research, with a view to using the extended knowledge for improvements to current mix design and structural design practices. Finally, the fundamental theories on thermo-conductivity and the mechanical properties of the BSM were used to create a relationship between temperature and mechanical properties in a pavement section. A laboratory testing programme was set up to study the properties and behaviour of BSMs and to establish links with the compositional factors, i.e. the type of binder used, the percentage of RA in the mix and the addition of a small amount of cement as active filler. BSMs were blended in three different proportions of RA and good quality crushed stone materials: 100% RA (with 2 % bitumen content), 50% RA and 50% G2 Hornfels crushed stone (with 2.1% bitumen content) and 100% G2 (with 2.3 % bitumen content). Tri-axial testing was carried out to determine shear parameters, resilient modulus and permanent deformation behaviour, while brushing testing was carried out to determine the possible durability performance of the BSMs. The mixture durability in terms of moisture damage was investigated. Temperature data were collected and a model to accurately simulate the temperature distribution in the BSMs was identified and proposed for further investigation and validation. It was found from the laboratory temperature data collected in this study that the temperature gradient varied according to the depth of the BSMs. A considerable part of the efforts of this study were dedicated to characterise and model the temperature distribution in a pavement section, taking into account the mechanical properties and performance of the BSMs at different temperature layers. The study provides an insight into fundamental mechanical performance, material durability properties, and the thermal capacity and conductivity of the BSM-foam mixes with high percentage of RA. This will assist in improving the current procedure for selection, combining and formulation of the mix matrices for BSMs. In addition, the study provides guidelines that will enable practitioners to confidently understand the relationship between temperature gradient and mechanical behaviours of BSM-foam pavement section. The specific durability-related issues addressed in this study are substance for future research. / AFRIKAANSE OPSOMMING: Die toenemende gebruik van herwonne asfalt (Engels: reclaimed asphalt (RA)) in bitumen gestabiliseerde materiaal (Engels: Bitumen Stabilised Materials (BSMs)), tekortkominge in die bestaande ontwerpriglyne- en handleidings en deurlopende verbeteringe in die konsepte en begrip van hierdie material vereis verdere navorsing oor die fundamentele eienskappe en gedrag van BSM. In die literatuurstudie word die huidige stand van kennis van die ontwerp van skuimbitumentegnieke ondersoek. Die literatuurstudie dek ook die huidige beste praktyke in die ontwerp van BSM en plaveisels wat hierdie materiale insluit. Tekortkominge en areas van verdere verbetering in die ontwerppraktyke is geïdentifiseer. Onlangse omgewingswetgewing verhoog die belangrikheid van BSM tegnologie, insluitend RA, as ‘n meer omgewingsvriendelike en volhoubare konstruksie-tegniek. Hierdie faktor sal in die toekoms al hoe belangriker word. Die verandering in die gedrag van materiaal en die falingsmeganismes van BSM mengsels is langtermynverskynsels. Dit impliseer dat die studie van die fisio-chemiese en meganiese eienskappe van mengsels met toenemende verhoudings van RA van kardinale belang is’n Fundamentele begrip van die vogskade en temo-fisiese eienskappe, wat verwant is aan die materiale se eienskappe, word vereis. Die primêre doelwit van die studie is die bevordering van BSM tegnologie deur die invloed van die geselekteerde materiale op duursaamheid, temperatuurverspreiding en langtermyn gedrag in al die fases van toepassing (mengselontwerp, konstruksie en in-dienstoestand) te bepaal. Die verhandeling begin met ‘n omvattende literatuuroorsig van navorsing oor die interaksie tussen RA en mineraalaggregate. Die eienskappe van RA en die mineraalaggregate word bespreek. Dit word gevolg deur ‘n oorsig van die meganiese eienskappe van die BSM-skuimbitumenmengsels met ‘n hoë persentasie RA en die duursaamheidgedrag daarvan. Faktore wat die temperatuurgradient van BSM beïnvloed word dan aangetoon. ‘n Beter begrip van die fundamentele gedragseienskappe en die invloed van temperatuur op die gedrag van BSM met ‘n hoë persentasie RA is een van die sleutelfaktore van hierdie navorsing. Dit het ten doel om die uitgebreide kennis te gebruik om huidige mengselontwerp en strukturele ontwerppraktyke te verbeter. Laastens is die fundamentele teorie van termogeleiding en die meganiese eienskappe van BSM gebruik om ‘n verhouding tussen temperature en meganiese eienskappe in ‘n plaveiselsnit te ontwikkel. ‘n Laboratoriumtoetsprogram is opgestel om die eienskappe en gedrag van BSM te bestudeer en om verwantskappe tussen samestellende faktore soos die tipe bindmiddel gebruik, die persentasie RA in die mengsel en die toediening van klein hoeveelhede sement as aktiewe vuller te bepaal. BSM is in drie verskillende verhoudings van RA en goeie gehalte gebreekte klipmateriaal vermeng: 100% RA met 2 % bitumen, 50% RA en 50 % G2 Hornfels gebreekte klip met 2.1 % bitumen en 100% G2 met 2.3 % bitumen. Drie-assige druktoetse is gebruik om skuifsterkteparameters, elastiese modulus en permanente vervormingsgedrag te bepaal. Borseltoetse is gebruik om die duursaamheidgedrag van BSM te bepaal. Die mengsels se duursaamheid is ook in terme van vogskade ondersoek.
69

Pós-tratamento e desinfecção de efluentes de reatores UASB e de lagoas de estabilização visando ao uso agrícola. / Post-treatment and disinfection of effluent from UASB reactors and of stabilization ponds, aiming to use in agricultural soils.

Sundefeld Júnior, Gilberto Carlos 25 July 2012 (has links)
Estudaram-se soluções para o pós-tratamento de efluentes de reatores UASB e de lagoas de estabilização visando à utilização em irrigação de culturas agrícolas. Nesta aplicação, normalmente são desejáveis bons níveis de remoção de sólidos em suspensão e graus elevados de desinfecção, além da conservação dos principais nutrientes. No caso do efluente de reatores UASB em escala real, foram construídas unidades em escala piloto envolvendo sedimentação, filtração e radiação UV. No primeiro experimento, o efluente dos reatores UASB passou por filtro de areia pressurizado em alta taxa e por reator UV de fluxo contínuo. Nesta etapa a concentração de sólidos em suspensão (SST) no efluente dos reatores UASB teve média de 233 mg/L, devido a problemas operacionais, sendo que o filtro apresentou eficiência média de 60% de remoção de sólidos em suspensão. Porém, como o filtrado apresentou absorbância ainda elevada, média de 0,476 cm-¹, a desinfecção UV resultou ineficiente e a contagem de coliformes do efluente final incompatível com o uso agronômico pretendido. No segundo experimento, o efluente dos reatores UASB recebeu tratamento complementar passando por decantador de alta taxa e filtração em leito de manta geotêxtil, seguindo finalmente para a desinfecção UV. A concentração de SST no efluente dos reatores UASB, sanados os problemas operacionais da ETE teve valor médio de 82 mg/L. Com essa concentração afluente relativamente baixa, o decantador lamelar demonstrou-se pouco eficiente e apresentou efluente com SST médio de 67 mg/L. No entanto, foi bastante útil para conter picos de concentração de sólidos no efluente dos reatores UASB, protegendo a etapa posterior de filtração. No efluente do filtro de manta geotêxtil, o SST médio foi de apenas 7 mg/L., ABS (254nm) de 0,245 cm-1 e Turbidez de 11 UNT. A desinfecção do efluente por radiação ultravioleta com dose recebida de 2,44 W.h/m³, resultou satisfatória com média geométrica de 1,12x101 NMP/100mL de E coli. No caso do efluente de sistema de lagoas de estabilização em escala real, aplicou-se pós-tratamento em escala piloto composto de filtro de areia pressurizado de alta taxa seguido de desinfecção por hipoclorito de sódio. A concentração de SST no efluente da lagoa facultativa teve média de 117 mg/L, enquanto que a média no efluente do filtro foi de 87 mg/L. Para concentrações de cloro dosado de 2,9; 6,2 e 11,7 mg/L, as médias geométricas das densidades de E coli no efluente final resultaram 1,13x10² NMP/100mL, 1,01x101 NMP/100mL e valor não detectado pelo método, respectivamente. Concluiu-se que é possível aplicar pós-tratamentos relativamente simples aos efluentes de reatores UASB e de lagoas de estabilização, quando se deseja uso agronômico e as principais condições operacionais destas unidades puderam ser avaliadas. / It was studied the application of a simple and economical post-treatment of effluent from wastewater treatment plant for the purpose of use on irrigation of agricultural crops. The research was conducted in two different wastewater treatment plants, (1) WTP UASB reactors with two application of post-treatment: (1.1) Post treatment with a sand bed filter pressurized at high-rate followed by ultraviolet disinfection. In this step, the concentration of suspended solids (TSS) in the effluent from the UASB reactor was 233 mg/L, the filter had efficiencies of 60% removal of suspended solids in the effluent from the UASB reactor, however, was not an appropriate result for effective disinfection of the effluent in the ultraviolet reactor. Absorbance values reached an average of 0.476 cm-¹. (1.2) Post-treatment at a high rate clarifier and on geotextile bed filtration to apply the ultraviolet disinfection. The concentration of TSS in the UASB reactor effluent has an average value of 82 mg/L, the concentration of the same parameter in the effluent from the clarifier was 67 mg/L and effluent of the filter geotextile, 7 mg/L. The system removed 91% of TSS in the effluent of the UASB reactor. In this experiment there was obtained a post-treated effluent with ABS (254nm) of 0.245 cm-1 and a turbidity of 11 NTU. The disinfection of the effluent by ultraviolet radiation with a dose received of 2.44 W.h/m³, obtained satisfactory results with geometric mean of 1.12x101 NMP/100mL E coli. (2) WTP by stabilization ponds with post-treatment in a pressurized sand filter followed by highrate disinfection by sodium hypochlorite solution. A TSS concentration in the effluent from facultative pond had an averaged 117 mg/L, the concentration of the same parameter in the effluent of the filter was 87 mg/L. With application of 2.88 mgCl2/L resulted in 1.13x10² NMP/100mL E coli, for the application of 6.2 and 11.7 mg/L chlorine was obtained 1.01x101 NMP/100mL E coli and ND, respectively.
70

Análise de impactos ambientais da restauração de um pavimento asfáltico pela Avaliação do Ciclo de Vida / Environmental impact analysis of asphalt pavements rehabilitation by Life Cycle Assessment

Savietto, Júlia Panzarin 07 July 2017 (has links)
A infraestrutura de transportes traz benefícios sociais e econômicos, porém traz também inevitáveis impactos ambientais que não podem ser negligenciados, como supressão da vegetação local e poluição atmosférica. Esses impactos ambientais podem ser quantificados e analisados pela técnica Avaliação do Ciclo de Vida (ACV), que cria a possibilidade de contemplar o aspecto ambiental na tomada de decisões e pode trazer melhor compreensão da cadeia produtiva. Na última década, é crescente a utilização dessa técnica na área de pavimentação, entretanto ainda é pouco usual no Brasil. O objetivo dessa dissertação é avaliar os impactos ambientais produzidos por duas técnicas de restauração de pavimentos asfálticos, comparando-se os resultados de ACV que observaram as fases de produção de materiais e de transportes. Dois cenários de restauração foram estudados, o primeiro considerou uma mistura asfáltica composta exclusivamente por materiais virgens (restauração convencional), e o segundo, considerou uma mistura asfáltica composta por 35% de Reciclado de Pavimento Asfáltico (RPA). As ACV foram procedidas de três maneiras distintas: (a) com o banco de dados e software alemão GaBi e o método EDIP 1997, (b) com o banco de dados da USLCI e pelo método do EDIP 1997, e (c) com software PavementLCA e o método TRACI. Os resultados obtidos a partir dos três diferentes procedimentos indicaram que a restauração com RPA apresentou redução dos impactos ambientais potencias quando comparada com a restauração convencional. Observou-se também que, para a maioria das análises, a atividade que mais contribuiu para os impactos das duas estratégias de restauração foi a de produção dos materiais. A análise de sensibilidade dos resultados obtidos com o GaBi e com o USLCI mostrou diferenças consideráveis, causadas pelas diferentes fontes de dados. Apesar de ser uma técnica em crescimento, a ACV ainda apresenta limitações quando aplicada a pavimentos, sobretudo, pela complexidade de seu ciclo de vida e pelas incertezas que envolvem sua elaboração, assim, estudos sobre ACV devem continuar, a fim de padronizar a técnica para a área e, com o tempo, obter resultados cada vez mais precisos. / Transportation infrastructure brings social and economic benefits, but it also brings unavoidable environmental impacts that can not be neglected, such as suppression of local vegetation and air pollution. These environmental impacts can be quantified and analyzed by the Life Cycle Assessment (LCA) technique, which creates the possibility of contemplating the environmental aspect in decision making and can provide a better understanding of the production chain. In the last decade, the use of this technique in the area of pavement is increasing, although not very usual in Brazil. The goal of this thesis is to analyze the environmental impacts produced by two asphalt pavement rehabilitation techniques, comparing the LCA results of material production and transportation phases. Two rehabilitation scenarios were studied, the first one considering an asphalt mixture composed exclusively by raw materials (conventional rehabilitation), and the second one considered an asphalt mixture composed by 35% of Reclaimed Asphalt Pavement (RAP). The LCA was done in three different ways: (a) with the German database and software GaBi and the EDIP 1997 method, (b) with the USLCI database and the EDIP 1997 method, and (c) with PavementLCA software and the TRACI method. The results obtained from the three different procedures indicated that the rehabilitation with RPA showed reduction of the potential environmental impacts when compared with the conventional rehabilitation. It was also observed that for the majority of the analysis, the activity that contributed the most to the impacts of the two rehabilitation strategies was the material production one. The sensitivity analysis of the results obtained with GaBi and with USLCI showed considerable differences in their values, caused by the different data sources. Although it is a growing technique, LCA still presents limitations when applied to pavements, mainly due to the complexity of its life cycle and the uncertainties involved in its elaboration, so studies about LCA should continue with the aim of standardizing the technique for the area and, over time, achieve increasingly more accurate results.

Page generated in 0.0333 seconds