J. Cañavate, P. Casas, F. Carrillo, F. Nogués and X. Colom
Disposal of end of life tyres is regulated in many countries. The enormous amount produced every year needs the research of new ways of recycling. A common practice previous to…
Abstract
Disposal of end of life tyres is regulated in many countries. The enormous amount produced every year needs the research of new ways of recycling. A common practice previous to any treatment is the grinding of the tyres by specialized companies producing ground tyre rubber powder. Several attempts to include this powder in polymeric matrixes have been developed, mainly resulting in a lack of compatibility of the components. In this paper we propose a new composite including GTR and EPDM in a HDPE matrix. The use of peroxides to produce crosslinking produces a thermoelastomeric material suitable for industrial applications.
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Yutian Yao, Qiusheng Song, Xiansu Cheng, Yonghai Song and Ben Liu
The purpose of this study is to investigate the effect of chlorination on the structure and properties of reclaimed rubber and to discuss the feasibility of a novel method to…
Abstract
Purpose
The purpose of this study is to investigate the effect of chlorination on the structure and properties of reclaimed rubber and to discuss the feasibility of a novel method to chlorinate reclaimed rubber.
Design/methodology/approach
A series of chlorinated reclaimed rubber with different chlorination degrees (CD) was prepared by suspension chlorination in aqueous phase (SCAP). Their structure and performance were characterized by Fourier transform infrared spectrometer, energy dispersive spectroscopy, scanning electron microscopy, thermogravimetric and mechanical property test.
Findings
The chemistry structure, mechanical performance and heat resistance of CRR is affected greatly by its CD.
Research limitations/implications
Although in the present work only chlorination of reclaimed rubber is researched, but this method can be used to modify other recycled rubber.
Practical implications
SCAP is a useful method to produce CRR, and it is feasible for production of chlorinated recycled rubber in large scale. The present work provides a new strategy to fabricate new materials based on recycled rubber.
Social implications
Chlorination of reclaimed rubber by SCAP is useful to convert waste rubber into new materials, and it is useful to decrease environment pollution.
Originality/value
SCAP method provides a new technology to chlorinate waste rubber with many merits, such as chlorination rate of RR is accelerated and the reaction can be controlled or adjusted easily. Moreover, conversion of chlorine is increased remarkably.
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Qing Bao, Baojin Wang, Manman Li, Chao Li and Jin Gao
A section of in-service PE gas pipeline in Guocun, Beijing, was found to appear gas leaking at the electrofusion (EF) joint. This study is dedicated to reveal the material cause…
Abstract
Purpose
A section of in-service PE gas pipeline in Guocun, Beijing, was found to appear gas leaking at the electrofusion (EF) joint. This study is dedicated to reveal the material cause of EF joint failure to help with a more accurate prediction of service life of PE gas pipe and further normalize the construction of PE gas pipeline.
Design/methodology/approach
Defect detection was carried out on the leaking EF joint using ultrasonic phased array. The mechanical degradation and structural aging behavior was studied by tension test, FTIR technology, TG test and DSC test. The organic components in the soil surrounding the PE gas pipe failure area were qualitatively identified.
Findings
The results showed that the organic surfactants in the soil environment could accelerate the aging behavior of PE material, leading to a deterioration of mechanical properties and a serious reduction in the ability of the PE pipe and EF joint, especially at the welding defect, to resist external force.
Originality/value
A novel study was conducted to investigate the failure cause of the EF joint of in-service PE gas pipe, incorporating the analysis of environmental factors and structural deterioration.
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Queli Regina Fritsch Denes, Rosana de Cassia de Souza Schneider and Liane Mahlmann Kipper
The objective of the present research was to carry out a scientific map about life cycle assessment (LCA) and triple bottom line (TBL) at slaughterhouse areas, looking for Cleaner…
Abstract
Purpose
The objective of the present research was to carry out a scientific map about life cycle assessment (LCA) and triple bottom line (TBL) at slaughterhouse areas, looking for Cleaner Production practices aiming at recognizing strategic themes for maintaining the sustainability of productive systems, according to the development of sustainable practices and production evolution in slaughterhouse areas.
Design/methodology/approach
The literature analysis was based on general approach, with steps adapted of study phases and activities of preferred reporting items for systematic review and meta-analyses (PRISMA) recommendation guide to do systematic literature review. Activities were subdivided to discuss the results in two kinds of analysis: quantitative and qualitative.
Findings
The main findings of our study reinforce the LCA importance in slaughterhouses to promote Cleaner Production, so that the main measures suggested and/or adopted by different authors include the substitution of raw materials by feeding, with the adoption of grains, protein supplements with less environmental impact in the composition of the feed and changes in the processes seeking for better energy efficiency and optimization of water consumption in meat processing.
Research limitations/implications
There is another action of sustainability considering LCA and Cleaner Production practices in the industrial meat area that should also be considered. These actions are restricted to documents of business circulation, with limited access since they involve issues regarding innovations in economic and technological aspects of slaughterhouses, as well as industrial confidentiality. Furthermore, in patent bases it is possible to advance the studies looking for how the digital transformation has been carried out in this industrial branch, since the 4.0 transformation industry tends to use clean technologies.
Originality/value
There are LCA models with a systemic approach to measure the level of sustainability of a process, comprising analysis of impacts related to different areas: environmental, social and economic although in terms of the meat production chain, the impact analysis focuses mainly on the environmental area. So, future works should be developed in meat production chain to assess social and economic impacts, i.e. a sustainable LCA addressing the three areas to consolidate models and standardize metrics with a scientific basis.
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Upendra S. Gupta, Sudhir Tiwari and Uttam Sharma
The incompatibility of natural fibers with polymer matrices is one of the key obstacles restricting their use in polymer composites. The interfacial connection between the fibers…
Abstract
Purpose
The incompatibility of natural fibers with polymer matrices is one of the key obstacles restricting their use in polymer composites. The interfacial connection between the fibers and the matrix was weak resulting in a lack of mechanical properties in the composites. Chemical treatments are often used to change the surface features of plant fibers, yet these treatments have significant drawbacks such as using substantial amounts of liquid and chemicals. Plasma modification has recently become very popular as a viable option as it is easy, dry, ecologically friendly, time-saving and reduces energy consumption. This paper aims to explore plasma treatment for improving the surface adhesion characteristics of sisal fibers (SFs) without compromising the mechanical attributes of the fiber.
Design/methodology/approach
A cold glow discharge plasma (CGDP) modification using N2 gas at varied power densities of 80 W and 120 W for 0.5 h was conducted to improve the surface morphology and interfacial compatibility of SF. The mechanical characteristics of unmodified and CGDP-modified SF-reinforced epoxy composite (SFREC) were examined as per the American Society for Testing and Materials standards.
Findings
The cold glow discharge nitrogen plasma treatment of SF at 120 W (30 min) enhanced the SFREC by nearly 122.75% superior interlaminar shear strength, 71.09% greater flexural strength, 84.22% higher tensile strength and 109.74% higher elongation. The combination of improved surface roughness and more effective lignocellulosic exposure has been responsible for the increase in the mechanical characteristics of treated composites. The development of hydrophobicity in the SF had been induced by CGDP N2 modification and enhanced the size of crystals and crystalline structure by removing some unwanted constituents of the SF and etching the smooth lignin-rich surface layer of the SF particularly revealed via FTIR and XRD.
Research limitations/implications
Chemical and physical treatments have been identified as the most efficient ways of treating the fiber surface. However, the huge amounts of liquids and chemicals needed in chemical methods and their exorbitant performance in terms of energy expenditure have limited their applicability in the past decades. The use of appropriate cohesion in addition to stimulating the biopolymer texture without changing its bulk polymer properties leads to the formation and establishment of plasma surface treatments that offer a unified, repeatable, cost-effective and environmentally benign replacement.
Originality/value
The authors are sure that this technology will be adopted by the polymer industry, aerospace, automotive and related sectors in the future.
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C.D. Pérez‐Segarra, A. Oliva, M. Costa and F. Escanes
In this paper a numerical simulation, based on finite differencetechniques, has been developed in order to analyse turbulent natural andmixed convection of air in internal flows…
Abstract
In this paper a numerical simulation, based on finite difference techniques, has been developed in order to analyse turbulent natural and mixed convection of air in internal flows. The study has been restricted to two‐dimensional cavities with the possibility of inlet and outlet ports, and with internal heat sources. Turbulence is modelled by means of two‐equation k‐ε turbulence models, both in the simplest form using wall functions and in the more general form of low‐Reynolds‐number k‐ε models. The couple time average governing equations (continuity, momentum, energy, and turbulence quantities) are solved in a segregated manner using the SIMPLEX method. An implicit control volume formulation of the differential equations has been employed. Some illustrative numerical results are presented to study the influence of geometry and boundary conditions in cavities. A comparison of different k‐ε turbulence models has also been presented.
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H. Schweiger, A. Oliva, M. Costa, C.D. Pérez Segarra and A. Ivancić
Two‐dimensional finite difference calculations are carried out tostudy laminar flow in longitudinal and transverse convection rolls for threedifferent geometries: a single…
Abstract
Two‐dimensional finite difference calculations are carried out to study laminar flow in longitudinal and transverse convection rolls for three different geometries: a single rectangular cavity with high aspect ratio; a double cavity with a thin separation sheet; and a double cavity with a separation sheet and a honeycomb structure. The equations for the convection‐diffusion in the fluid and conduction in the solid region are solved simultaneously. Good agreement with experimental data is achieved for Rayleigh numbers not too high above the critical value for the onset of secondary convection rolls (Ra < 8500 for vertical and Ra < 2700 for horizontal cavities filled with air). Simulation fails for inclined cavities, where the flow structure is essentially three‐dimensional.
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Wasif Latif, Abdul Basit, Zulfiqar Ali and Sajjad Ahmad Baig
The purpose of this paper is to study the 100 percent pure cotton and 50:50 cotton and regenerated fibers (tencel, modal, bamboo, viscose) blends. The blends of regenerated fibers…
Abstract
Purpose
The purpose of this paper is to study the 100 percent pure cotton and 50:50 cotton and regenerated fibers (tencel, modal, bamboo, viscose) blends. The blends of regenerated fibers with cotton are studied so as to replace 100 percent cotton fabrics with the cotton blends as cotton cannot fulfill the demand of clothing due to the increasing population.
Design/methodology/approach
In order to conduct this study, cotton, as natural cellulose fiber, was used. Regenerated fibers include viscose, tencel, modal and bamboo. Five yarn samples of Ne 30/1 of 100 percent cotton and blends (50:50) of cotton with tencel, modal, bamboo and viscose fibers were produced. The blending was done in the Blow-room, and yarn samples were produced by employing the ring spinning technique. Plain woven fabrics samples with Ends (76) and Picks (68) per inch of 120 gsm were prepared. The fabric samples were tested for mechanical (warp and weft tensile and tear strengths) and comfort properties (air permeability, moisture management and thermal resistance).
Findings
Cotton:tencel fabric has the excellent mechanical (tensile and tear strength) as well as comfort properties (air permeability, moisture management and thermal resistance). It means that the most suitable blend that cotton can make with the regenerated fibers is the tencel. Therefore, to have more comfortable fabrics, the fabrics which are being made by 100 percent cotton can be replaced with the cotton:tencel.
Originality/value
To the authors’ information, no study has been reported in which all the regenerated fibers blended with cotton were studied. Hence, the aim of this work is to study the mechanical and comfort properties of the regenerated fibers (modal, tencel, viscose and bamboo) blended with cotton. The blends of cotton with regenerated fibers might replace 100 percent cotton in clothing applications as cotton cannot fulfill the increasing demanding of clothing.
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Heba Raslan, Khaled El-Nemr, Magdy Ali and Medhat Hassan
This study aims to investigate the influences of polyester fabric layers on the mechanical properties of SBR and devulcanized waste rubber composite materials, as well as the…
Abstract
Purpose
This study aims to investigate the influences of polyester fabric layers on the mechanical properties of SBR and devulcanized waste rubber composite materials, as well as the effect of gamma irradiation dose.
Design/methodology/approach
The devulcanized waste rubbers (DWR) were carried out by different methods. First, chemically, by two different reclaiming agents such as tetramethylthiuram disulfide (TMTD) and 2-mercapto benzothiazole disulfide (MBTS). Secondary by a physical method like microwave (MW). The devulcanized rubbers were mixed with virgin styrene butadiene rubber (SBR) in different ratios, as follows: SBR-DWR (TMTD) 50 / 50, SBR-DWR (MBTS) 80 / 20 and SBR-DWR (MW) 80 / 20. A series of sandwich polyester tire cord fabrics were used as reinforcement for making SBR and devulcanized waste rubber composite materials and molded on a hot press into rubber sheet films, then subjected to gamma radiation at different doses ranging from 100 up to 200 kGy.
Findings
The experimental results indicate that increasing the layer number improves the mechanical properties of composites. The tensile strength, tearing, hardness and elastic modulus of the rubber composites increased with the rise of the fiber layers and by increasing the irradiation dose up to 200 kGy. The reclaiming agent TMTD gave the best results for mechanical properties, followed by MW and then MBTS.
Originality/value
This phenomenon can be detailed based on the fact that when the fiber-reinforced composites are subjected to loading, the fibers act as load carriers, depending on the population and orientation of the fibers. Also, scanning electron microscopy (SEM) reveals that adhesion was caused by tire cord fabrics and rubber blend matrix.
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F. Escanes, C. D. Pérez‐Segarra and A. Oliva
This paper deals with a numerical simulation of the thermal andfluid‐dynamic behaviour of double‐pipe condensers and evaporators. Thegoverning equations of the fluid flow…
Abstract
This paper deals with a numerical simulation of the thermal and fluid‐dynamic behaviour of double‐pipe condensers and evaporators. The governing equations of the fluid flow (continuity, momentum and energy) in both the tube (evaporating or condensing flow) and the annulus (single‐phase flow), together with the energy equation in the tube wall, are solved iteratively in a segregated manner using a one‐dimensional, transient formulation, based on an implicit step by step numerical scheme in the zones with fluid flow (tube and annulus), and an implicit central difference numerical scheme in the tube wall, solved by means of the Tri‐Diagonal Matrix Algorithm (TDMA). This formulation requires the use of empirical information for the evaluation of convective heat transfer, shear stress and void fraction. Two criteria to calculate the location of the points of transition between single‐phase and two‐phase flow are tested. An analysis of the different parameters used in the discretization is made. Some illustrative results corresponding to the solution of a condenser and an evaporator using two different working fluids (R–12 and R–134a) are presented.