A natural ice boom

Energy Technology Data Exchange (ETDEWEB)

Hopper, H.R. [Manitoba Hydro, Winnipeg, MB (Canada)

1998-10-01

Planning for ice jams and ice movements are critical on the Nelson River in northern Manitoba in designing cofferdams. Experience on the St. Lawrence River demonstrated the possibility of exercising some control over ice action by judicious placement of log booms or ice control structures. The success of experiments with man-made controls led to field tests in which an ice sheet of sufficient magnitude and competence was introduced into the open water stream of the Nelson River. The ice sheet was subsequently jammed in a narrow channel, thereby creating a natural ice bridge or boom upstream of a proposed hydro development. Under favourable conditions, this boom would initiate the progression of the ice cover from its location upstream, cutting off the downstream reach from the ice producing potential of the upstream reach. Although ice would still be generated downstream, the length of the reach between the ice boom and the development site would be short enough that ice jamming at the development site would never occur. Although problems in blasting prevented the introduction of a competent ice sheet into the main stream of the river at the location chosen, sufficient confidence in the theory was gained to warrant further consideration. 4 refs., 1 tab., 10 figs.

Domestic Crop Booms, Livelihood Pathways and Nested Transitions: Charting the Implications of Bangladesh’s Pangasius Boom

NARCIS (Netherlands)

Belton, B.; Asseldonk, van I.J.M.; Bush, S.R.

2017-01-01

Rapidly transforming Asian food systems are oriented largely towards domestic markets, yet literature on Asian crop booms deals almost exclusively with commodities produced for export. With reference to pangasius aquaculture in Bangladesh, we argue that ‘domestic crop booms’ - agricultural booms

Testing fire resistant boom in waves and flames

International Nuclear Information System (INIS)

McCourt, J.; Buist, I.; Pratte, B.; Jamieson, W.; Mullin, J.

1997-01-01

A near full-scale screening test to evaluate the durability and ability of refractory-fabric fire resistant booms to contain oil during an in-situ burn without the environmental problems of burning crude oil or the cost of testing offshore, was developed. The boom was first flexed under tension for two hours, then deployed in a U-configuration in an outdoor wave tank. Propane gas was burned in the pocket of the boom to simulate the collection and burning phases of an in-situ burn. Finally, the boom was returned to the indoor wave flume for another two hours of wave action and then inspected for damage. Results indicated damage of the same type as suffered in previously conducted sea trials, although the extent of damage was less severe. These results led to recommendations for improvement of the test protocol which included: (1) increasing the heat flux to the boom, (2) improving the heat flux measurement, (3) increasing the tension in the fire boom during flame testing, and (4) improving the characterization of the waves near the fire boom. 16 refs., 6 figs

Waveforms and Sonic Boom Perception and Response (WSPR): Low-Boom Community Response Program Pilot Test Design, Execution, and Analysis

Science.gov (United States)

Page, Juliet A.; Hodgdon, Kathleen K.; Krecker, Peg; Cowart, Robbie; Hobbs, Chris; Wilmer, Clif; Koening, Carrie; Holmes, Theresa; Gaugler, Trent; Shumway, Durland L.;

Prediction of heat generation in rubber or rubber-metal springs

Directory of Open Access Journals (Sweden)

Banić Milan S.

2012-01-01

Full Text Available The temperature of rubber or rubber-metal springs increases under cyclic loading, due to hysteresis losses and low rubber thermal conductivity. Hysteresis losses correspond to energy dissipation from the rubber, which is primarily converted into heat. This well-known phenomenon, called heat build-up, is the primary reason for rubber aging. Increase in temperature within the rubber compound leads to degradation of its physical and chemical properties, increase in stiffness and loss of damping capability. This paper presents a novel procedure of heat generation prediction in rubber or rubber-metal springs. The procedure encompasses the prediction of hysteresis loss, i. e. dissipated energy within the rubber, by finite element analysis and application of a modern visco-plastic rubber constitutive model. The obtained dissipated energy was used as an input for transient thermal analysis. Verification of the proposed procedure was performed by comparison of simulation results with experimentally obtained data during the dynamic loading of the rubber specimen. The proposed procedure is highly computationally efficient and it enables time integration, which can be problematic in coupled mechanical thermal analysis. [Projekat Ministarstva nauke Republike Srbije, br. TR35005: Research and Development of New Generation of Wind Turbines of High Energy Efficiency

CONFIGURACION DEL FRENTE RIBEREÑO EN QUILLOTA. CONFORMACION DE UN NUEVO FRENTE PACIFICO PARA EL CONTINENTE

OpenAIRE

ARAYA GLADINIER, JEAN CRISTOPHER; ARAYA GLADINIER, JEAN CRISTOPHER

2012-01-01

Este trabajo se inscribe en el plan maestro para Quillota, junto con el desarrollo un barrio sustentable en el nuevo borde del río Aconcagua frente a Quillota. Ubicado esta vez al Poniente del actual puente del Boco. Y desarrollándose como frente de renovación urbana Se toma en cuenta como antecedente de proyecto, el desarrollado por Nuestra Escuela en los años 80, en el que se propone un nuevo borde de frente fluvial para Quíllota, y un modo de abordar el cerro Mayaca con edificios hab...

Rubber mixing process and its relationship with bound rubber and crosslink density

Science.gov (United States)

Hasan, A.; Rochmadi; Sulistyo, H.; Honggokusumo, S.

2017-06-01

This research studied the relationship between bound rubber and crosslink density based on rubber mixing process. Bound rubber was obtained after natural rubber was masticated and mixed with rubber chemicals and filler while crosslink density was collected after rubber compound was vulcanized. Four methods are used and each method refers to four ways of incorporating carbon black during mixing. The first method, after rubber was masticated for 5 minutes, the addition of rubber chemicals and filler was done simultaneously. Rubber was masticated for 1 minute and continued mixing of rubber chemicals and filler where mixing was different from first method. This was the second method. The third method was the same as the second method but the filler used N 660 while in the second method N 330. The last method is not the same as the first and second, the rubber is only masticated for 3 minutes and then mixed with filler and followed by rubber chemicals sequentially. The results showed that bound rubber and crosslink density were influenced by mixing and mastication process. Bound rubber dropped and crosslink density was relatively stable in the first three mixing methods for increasing carbon black at the beginning of the mixing process. Bound rubber and crosslink density stated opposite results in the fourth mixing method. The higher the bound rubber the lower the crosslink density. Without regard to mixing methods, there is a non-linear relationship between bound rubber formation and crosslink density determination

Del Boom y otras onomatopeyas literarias

Directory of Open Access Journals (Sweden)

Jorge Iván Parra Londoño

2016-03-01

Full Text Available Este artículo trata de examinar los alcances literarios del llamado Boom latinoamericano, a medio siglo de su estallido, las cuatro obras más representativas y sus respectivos autores, además de proponer un quinto autor, según la invitación que hiciera en su momento el crítico Ángel Rama. Por otro lado, evalua la respuesta literaria por parte del Post Boom, analizando sus características y su vigencia y, de manera concomitante, los movimientos anejos o posteriores a dicho movimiento, como el Crack y la Generación Granta. A manera de propuesta, se pondrán a consideración treinta autores como integrantes del Post Boom y una novela de Carlos Fuentes como el “crash” del Boom. Por último, presenta un breve vistazo a la narrativa española paralela a los mencionados movimientos.

The Effect of Sonic Booms on Earthquake Warning Systems

Science.gov (United States)

Wurman, Gilead; Haering, Edward A, Jr.; Price, Michael J.

2011-01-01

Several aerospace companies are designing quiet supersonic business jets for service over the United States. These aircraft have the potential to increase the occurrence of mild sonic booms across the country. This leads to interest among earthquake warning (EQW) developers and the general seismological community in characterizing the effect of sonic booms on seismic sensors in the field, their potential impact on EQW systems, and means of discriminating their signatures from those of earthquakes. The SonicBREWS project (Sonic Boom Resistant Earthquake Warning Systems) is a collaborative effort between Seismic Warning Systems, Inc. (SWS) and NASA Dryden Flight Research Center. This project aims to evaluate the effects of sonic booms on EQW sensors. The study consists of exposing high-sample-rate (1000 sps) triaxial accelerometers to sonic booms with overpressures ranging from 10 to 600 Pa in the free field and the built environment. The accelerometers record the coupling of the sonic boom to the ground and surrounding structures, while microphones record the acoustic wave above ground near the sensor. Sonic booms are broadband signals with more high-frequency content than earthquakes. Even a 1000 sps accelerometer will produce a significantly aliased record. Thus the observed peak ground velocity is strongly dependent on the sampling rate, and increases as the sampling rate is reduced. At 1000 sps we observe ground velocities that exceed those of P-waves from ML 3 earthquakes at local distances, suggesting that sonic booms are not negligible for EQW applications. We present the results of several experiments conducted under SonicBREWS showing the effects of typical-case low amplitude sonic booms and worst-case high amplitude booms. We show the effects of various sensor placements and sensor array geometries. Finally, we suggest possible avenues for discriminating sonic booms from earthquakes for the purposes of EQW.

Rubber glove wearing device

International Nuclear Information System (INIS)

Nozaki, Tatsuo; Takada, Kaoru.

1994-01-01

Rubber groves are attached each to an upper end of a glove putting vessel having an air-sucking hole on the bottom by enlarging an opening end of the rubber glove and turning back the inside to the outside. When the sucking device is operated, air in the glove putting device is sucked and the rubber glove is expanded by an atmospheric pressure. After expansion of the rubber glove to some extent, the sucking device is stopped, and presence or absence of failures of the rubber glove is confirmed by shrinkage of the rubber glove and by an indication value of a pressure gauge for detecting the pressure change in the vessel. Then, a hand is inserted to the expanded rubber glove, and a detaching switch in the vessel is pushed by a finger tip. A detaching piece at the upper end of the vessel is protruded outwardly to enlarge the turned-back portion of the rubber glove to easily release the rubber glove from the putting vessel, and the rubber glove is put on. This enables to wear the rubber glove and conduct failure test simultaneously. Further, a user can put on the rubber glove without touching the outside of the rubber glove. (I.N.)

PROPERTIES TYRE TREAD RUBBERS DEPENDING ON PARTICULARITY OF RUBBER COMPOUND

Directory of Open Access Journals (Sweden)

Z. S. Shashok

2014-01-01

Full Text Available Summary. The results of studies of the elastomeric compositions based on natural rubber containing curatives different ratio "curing agent : vulcanization accelerator" listed in this article. Influence of the composition of the vulcanizing group on stress-strain and elastic- deformation properties of tire tread rubber was installed. It has been shown that a significant effect on thermo-oxidative aging of vulcanizates was the composition of the vulcanizing group. Results of studies resistance tread rubber to exposure to elevated temperatures were presented . Vulcanizates differing type and density by varying the cross-linking ratio of "curing agent : vulcanization accelerator" were obtained . Research results in the formation of rubber resistance and crack growth at different temperatures were presented. Revealed that the best education and resistance to tear propagation under normal conditions characterized by rubber ratio "curing agent : vulcanization accelerator" equal to 1.5:1. It has been established that a dynamic endurance study rubbers depends largely on the nature and concentration of the cross-linking cross-links and movable promote increase efficiency due to the grid and reduce the sulfidity rearrangement. During loading mode alternating deformations at elevated temperatures lability of polysulfide bonds negatively affects the performance of rubber, and the decisive role of providing strength and thermal cross-linking. It is shown that the performance of the spatial grid rubbers allow indirectly judge the dynamic vulcanizates endurance and predict performance rubbers at elevated temperatures under conditions of repeated cyclic deformation. Revealed that the vulcanizing system containing sulfur and vulcanization accelerator TBBS 1:2, promotes the formation of the optimal structure of vulcanized rubber , which provides the best resistance to repeated cyclic deformations in the operating temperatures of the tire.

Subjective Response to Simulated Sonic Booms in Homes

Science.gov (United States)

McCurdy, David A.; Brown, Sherilyn A.

1996-01-01

One of the environmental issues affecting the development of a second-generation supersonic commercial transport is the impact of sonic booms on people. Aircraft designers are attempting to design the transport to produce sonic boom signatures that will have minimum impact on the public. Current supersonic commercial aircraft produce an 'N-wave' sonic boom pressure signature that is considered unacceptable by the public. This has resulted in first-generation supersonic transports being banned from flying supersonic over land in the United States, a severe economic constraint. By tailoring aircraft volume and lift distributions, designers hope to produce sonic boom signatures having specific shapes other than 'N-wave' that may be more acceptable to the public. As part of the effort to develop a second-generation supersonic commercial transport, Langley Research Center is conducting research to study people's subjective response to sonic booms. As part of that research, a system was developed for performing studies of the subjective response of people to the occurrence of simulated sonic booms in their homes. The In-Home Noise Generation/Response System (IHONORS) provides a degree of situational realism not available in the laboratory and a degree of control over the noise exposure not found in community surveys. The computer-controlled audio system generates the simulated sonic booms, measures the noise levels, and records the subjects' ratings and can be placed and operated in individual homes for extended periods of time. The system was used to conduct an in-home study of subjective response to simulated sonic booms. The primary objective of the study was to determine the effect on annoyance of the number of sonic boom occurrences in a realistic environment. The effects on annoyance of several other parameters were also examined. Initially, data analyses were based on all the data collected. However, further analyser found that test subjects adapted to the sonic

In-depth proteome analysis of the rubber particle of Hevea brasiliensis (para rubber tree).

Science.gov (United States)

Dai, Longjun; Kang, Guijuan; Li, Yu; Nie, Zhiyi; Duan, Cuifang; Zeng, Rizhong

2013-05-01

The rubber particle is a special organelle in which natural rubber is synthesised and stored in the laticifers of Hevea brasiliensis. To better understand the biological functions of rubber particles and to identify the candidate rubber biosynthesis-related proteins, a comprehensive proteome analysis was performed on H. brasiliensis rubber particles using shotgun tandem mass spectrometry profiling approaches-resulting in a thorough report on the rubber particle proteins. A total of 186 rubber particle proteins were identified, with a range in relative molecular mass of 3.9-194.2 kDa and in isoelectric point values of 4.0-11.2. The rubber particle proteins were analysed for gene ontology and could be categorised into eight major groups according to their functions: including rubber biosynthesis, stress- or defence-related responses, protein processing and folding, signal transduction and cellular transport. In addition to well-known rubber biosynthesis-related proteins such as rubber elongation factor (REF), small rubber particle protein (SRPP) and cis-prenyl transferase (CPT), many proteins were firstly identified to be on the rubber particles, including cyclophilin, phospholipase D, cytochrome P450, small GTP-binding protein, clathrin, eukaryotic translation initiation factor, annexin, ABC transporter, translationally controlled tumour protein, ubiquitin-conjugating enzymes, and several homologues of REF, SRPP and CPT. A procedure of multiple reaction monitoring was established for further protein validation. This comprehensive proteome data of rubber particles would facilitate investigation into molecular mechanisms of biogenesis, self-homeostasis and rubber biosynthesis of the rubber particle, and might serve as valuable biomarkers in molecular breeding studies of H. brasiliensis and other alternative rubber-producing species.

Promoting the use of crumb rubber concrete in developing countries.

Science.gov (United States)

Batayneh, Malek K; Marie, Iqbal; Asi, Ibrahim

2008-11-01

The use of accumulated waste materials in third world countries is still in its early phases. It will take courage for contractors and others in the construction industry to recycle selected types of waste materials in the concrete mixes. This paper addresses the recycling of rubber tires accumulated every year in Jordan to be used in concrete mixes. The main objectives of this research were to provide more scientific evidence to support the use of legislation or incentive-based schemes to promote the reuse of accumulated waste tires. This research focused on using crumb tires as a replacement for a percentage of the local fine aggregates used in the concrete mixes in Jordan. Different concrete specimens were prepared and tested in terms of uniaxial compression and splitting tension. The main variable in the mixture was the volumetric percentage of crumb tires used in the mix. The test results showed that even though the compressive strength is reduced when using the crumb tires, it can meet the strength requirements of light weight concrete. In addition, test results and observations indicated that the addition of crumb rubber to the mix has a limited effect toward reducing the workability of the mixtures. The mechanical test results demonstrated that the tested specimens of the crumb rubber concrete remained relatively intact after failure compared to the conventional concrete specimens. It is also concluded that modified concrete would contribute to the disposal of the non-decaying scrap tires, since the amount being accumulated in third world countries is creating a challenge for proper disposal. Thus, obliging authorities to invest in facilitating the use of waste tires in concrete, a fundamental material to the booming construction industry in theses countries, serves two purposes.

Fracture behavior of rubber powder modified rubber blends applied for conveying belt top covers

OpenAIRE

Euchler, Eric; Stocek, Radek; Gehde, Michael; Bunzel, Jörg-Michael; Saal, Wolfgang; Kipscholl, Reinhold

2016-01-01

The aim of this study is concentrated on the experimental investigation of wear resistance of rubber powder modified rubber blends. Styrene-Butadiene-Rubber (SBR) blends applied for conveying belt top covers have been modified by ground rubber (rubber powder) based on SBR. We theoretically described the rubber wear mechanism due to loading conditions occurring at conveyor belts in the field, to simulate wear behavior of top cover rubber materials. An own developed testing equipment based on g...

Nitrile rubber and carboxylated nitrile rubber resistance to soybean biodiesel

Directory of Open Access Journals (Sweden)

Felipe Nunes Linhares

2018-03-01

Full Text Available Abstract Biodiesel has been considered a suitable substitute for petroleum diesel, but their chemical composition differs greatly. For this reason, biodiesel interacts differently than petroleum diesel with various materials, including rubbers. Therefore, the resistance of some elastomers should be thoroughly evaluated, specifically those which are commonly used in automotive industry. Nitrile rubber (NBR is widely used to produce vehicular parts that are constantly in contact with fuels. This paper aimed to assess the resistance of carboxylated nitrile rubber (XNBR with 28% of acrylonitrile content to soybean biodiesel in comparison with non-carboxylated nitrile rubber samples, with high and medium acrylonitrile content (33 and 45%. NBR with medium acrylonitrile content showed little resistance to biodiesel. However, carboxylated nitrile rubber even with low acrylonitrile content had similar performance to NBR with high acrylonitrile content.

Exposure to rubber fume and rubber process dust in the general rubber goods, tyre manufacturing and retread industries.

Science.gov (United States)

Dost, A A; Redman, D; Cox, G

2000-08-01

This study assesses the current patterns and levels of exposure to rubber fume and rubber process dust in the British rubber industry and compares and contrasts the data obtained from the general rubber goods (GRG), retread tire (RT) and new tire (NT) sectors. A total of 179 rubber companies were visited and data were obtained from 52 general rubber goods, 29 retread tire and 7 new tire manufacturers. The survey was conducted using a questionnaire and included a walk-through inspection of the workplace to assess the extent of use of control measures and the nature of work practices being employed. The most recent (predominantly 1995-97) exposure monitoring data for rubber fume and rubber process dust were obtained from these companies; no additional sampling was conducted for the purpose of this study. In addition to the assessment of exposure data, evaluation of occupational hygiene reports for the quality of information and advice was also carried out.A comparison of the median exposures for processes showed that the order of exposure to rubber fume (E, in mg m(-3)) is: E(moulding) (0.40) approximately E(extrusion) (0.33)>E(milling) (0.18) for GRG; E(press) (0. 32)>E(extrusion) (0.19)>E(autoclave) (0.10) for RT; and E(press) (0. 22) approximately E(all other) (0.22) for NT. The order of exposure to rubber fume between sectors was E(GRG) (0.40)>E(RT) (0.32)>E(NT) (0.22). Median exposures to rubber process dust in the GRG was E(weighing) (4.2)>E(mixing) (1.2) approximately E(milling) (0.8) approximately E(extrusion) (0.8) and no significant difference (P=0. 31) between GRG and NT sectors. The findings compare well with the study carried out in the Netherlands [Kromhout et al. (1994), Annals of Occupational Hygiene 38(1), 3-22], and it is suggested that the factors governing the significant differences noted between the three sectors relate principally to the production and task functions and also to the extent of controls employed. Evaluation of occupational

Full-Carpet Design of a Low-Boom Demonstrator Concept

Science.gov (United States)

Ordaz, Irian; Wintzer, Mathias; Rallabhandi, Sriram K.

2015-01-01

The Cart3D adjoint-based design framework is used to mitigate the undesirable o -track sonic boom properties of a demonstrator concept designed for low-boom directly under the flight path. First, the requirements of a Cart3D design mesh are determined using a high-fidelity mesh adapted to minimize the discretization error of the CFD analysis. Low-boom equivalent area targets are then generated at the under-track and one off-track azimuthal position for the baseline configuration. The under-track target is generated using a trim- feasible low-boom target generation process, ensuring that the final design is not only low-boom, but also trimmed at the specified flight condition. The o -track equivalent area target is generated by minimizing the A-weighted loudness using an efficient adjoint-based approach. The configuration outer mold line is then parameterized and optimized to match the off-body pressure distributions prescribed by the low-boom targets. The numerical optimizer uses design gradients which are calculated using the Cart3D adjoint- based design capability. Optimization constraints are placed on the geometry to satisfy structural feasibility. The low-boom properties of the final design are verified using the adaptive meshing approach. This analysis quantifies the error associated with the CFD mesh that is used for design. Finally, an alternate mesh construction and target positioning approach offering greater computational efficiency is demonstrated and verified.

Spray boom for selectively spraying a herbicidal composition onto dicots

DEFF Research Database (Denmark)

2012-01-01

There is provided a method and spray boom for discriminating cereal crop (monocot) and weeds (dicots). The spray boom includes means for digitally recording an image of a selected area to be treated by a nozzle on the spray boom, whereby a plant material is identified based on a segmentation proc...

Preparation of sulfonic acid-containing rubbers from natural rubber vulcanizates

Science.gov (United States)

Poonsawat, Worapong; Poompradub, Sirilux; Ngamcharussrivichai, Chawalit

2014-06-01

In this work, a series of sulfonic acid-containing rubbers were prepared by aqueous phase oxidation of natural rubber vulcanizates in the presence of hydrogen peroxide (H2O2) and formic acid (HCOOH). The starting vulcanizates were neatly prepared via an efficient vulcanization (EV) system by varying mass ratio of N-cyclohexyl-2-benzothiazole sulfonamide (CBS), as an accelerator, to sulfur. The oxidation conditions were controlled at the molar ratio of H2O2: HCOOH = 1:1, the concentration of H2O2 = 15 wt.%, the temperature = 50 °C, and the reaction time = 3 h. The rubber materials before and after the oxidation were characterized for their physicochemical properties by using Fourier transform infrared spectroscopy, bomb calorimetry, acid-base titration and swelling measurements. The results indicated the presence of sulfonic acid group in the oxidized rubbers, generated by the oxidative cleaves of sulfide crosslinks in the rubber vulcanizates. The oxidation decreased the sulfur content of the rubber in which the level of sulfur loss was determined by the CBS/sulfur ratio. Moreover, the acidity of the oxidized products was correlated with the amount of sulfur remaining.

The Effect of Rubber Mixing Process on The Curing Characteristics of Natural Rubber

Directory of Open Access Journals (Sweden)

Abu Hasan

2013-04-01

Full Text Available This research is aimed at studying the relationship between rubber mixing processes and curing characteristics of natural rubber. The curing characteristic analysis was carried out through a natural rubber formula having been masticated and mixed, followed by curing. As many as four mastication methods were finely applied; each respected four sequences of rubber mixing process. In the first method, rubber was masticated for 5 minutes and then rubber chemicals and carbon black N 330 were  simultaneously added. In the second and the third methods, rubber was masticated for 1 minute and then carbon blacks and rubber chemicals were also simultaneously added but using different type of fillers. In the fourth method, rubber was masticated for 3 minutes and then rubber chemicals and carbon black were subsequently added. The additions of rubber chemicals and carbon blacks to the masticated rubber were distinguished by the sequence and time allocated for each mixing process. The carbon blacks were added in two stages by which 10 phr was added first and the remaining 40 phr was added later along with oil. In another method, ratios of the carbon blacks addition (as done in the first  and the second stages were 20:30, 30:20, and 40:10. The examination results showed that rubber mixing process gave an impact on the changes of curing characteristics. They were much affected by the method of carbon black addition. The mixing temperature also had an effect on both curing time and curing rate in which the higher the mixing temperature, the lower the curing time and curing rate. Vulcanization temperature also affected the curing time and curing rate in which the higher the vulcanization temperature, the lower the curing time and the higher the curing rate. Lastly, particle size of carbon black also gave an impact on the curing time and curing rate in which the smaller the particle size, the lower the curing time and the higher the curing rate.

Development in helicopter tail boom strake applications in the US

Science.gov (United States)

Wilson, John C.; Kelley, Henry L.; Donahue, Cynthia C.; Yenni, Kenneth R.

1988-01-01

The use of a strake or spoiler on a helicopter tail boom to beneficially change helicopter tail boom air loads was suggested in the United States in 1975. The anticipated benefits were a change of tail boom loads to reduce required tail rotor thrust and power and improve directional control. High tail boom air loads experienced by the YAH-64 and described in 1978 led to a wind tunnel investigation of the usefullness of strakes in altering such loads on the AH-64, UH-60, and UH-1 helicopters. The wind tunnel tests of 2-D cross sections of the tail boom of each demonstrated that a strake or strakes would be effective. Several limited test programs with the U.S. Army's OH-58A, AH-64, and UH-60A were conducted which showed the effects of strakes were modest for those helicopters. The most recent flight test program, with a Bell 204B, disclosed that for the 204B the tail boom strake or strakes would provide more than a modest improvement in directional control and reduction in tail rotor power.

Radiation vulcanization of rubbers

Energy Technology Data Exchange (ETDEWEB)

Makuuchi, Keizo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

2002-02-01

An abstract of the radiation process of polymer materials and the polymer reaction by radiation is explained. Main radiation is 250 keV to 10 MeV of electron rays in the industry. Radiation cross-linked rubber has less the tensile strength than that by sulfur and organic peroxide crosslinking. The main origins of low tensile strength are caused by cut of backbone chain and ozone depend on radiation. Acceleration of crosslinking and short time of radiation are necessary to improve these defects. To accelerate crosslinking, we used crosslinking accelerators, for example, three poly-functional monomers (PFM). The maximum tensile strength of styrene-butadiene rubber (SBR) not added crosslinking accelerators showed 3 MPa at 110 kGy, but SBR added A-TMMT (tetramethylolmethane tetraacrylate) showed 5.5 MPa at 110 kGy. Radiation crosslinking of many kinds of rubber: isoprene (IR), SBR, CR, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), butyl rubber (IIR), chlorinated butyl rubber (CIIR), EPM and TPE are explained. (S.Y.)

Radiation vulcanization of rubbers

International Nuclear Information System (INIS)

Makuuchi, Keizo

2002-01-01

An abstract of the radiation process of polymer materials and the polymer reaction by radiation is explained. Main radiation is 250 keV to 10 MeV of electron rays in the industry. Radiation cross-linked rubber has less the tensile strength than that by sulfur and organic peroxide crosslinking. The main origins of low tensile strength are caused by cut of backbone chain and ozone depend on radiation. Acceleration of crosslinking and short time of radiation are necessary to improve these defects. To accelerate crosslinking, we used crosslinking accelerators, for example, three poly-functional monomers (PFM). The maximum tensile strength of styrene-butadiene rubber (SBR) not added crosslinking accelerators showed 3 MPa at 110 kGy, but SBR added A-TMMT (tetramethylolmethane tetraacrylate) showed 5.5 MPa at 110 kGy. Radiation crosslinking of many kinds of rubber: isoprene (IR), SBR, CR, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), butyl rubber (IIR), chlorinated butyl rubber (CIIR), EPM and TPE are explained. (S.Y.)

US rubber markets recover

International Nuclear Information System (INIS)

Wood, A.

1993-01-01

Synthetic rubber markets in North America bounced back in no uncertain terms last year, with demand climbing an impressive 9.5%, to 2.97 million m.t.; and, according to the International Institute of Synthetic Rubber Producers (IIS-RP; Houston) latest five-year forecast, producers can look forward to a 3.3% increase in demand during 1993. This growth rate outpaced out 1992 forecast and demonstrates the resilience of the synthetic rubber industry, says William E. Tessemer, managing director of IISRP. We expect demand in 1993 to surpass 1992 and level off at a 2%/year growth rate for synthetic rubber - 2.5% including thermoplastic elastomers [TPEs]-over the 1993-97 period. The improvement reflects signs of a recovery in North America, especially the pickup in the auto and tire industry. The two major tire rubbers - styrene butadiene and polybutadiene rubber - notched up double-digit gains, and other materials that have autos uses, such as nitrile rubber and many of the specialty elastomers, also advanced strongly

Rubber molds for investment casting

International Nuclear Information System (INIS)

Sibtain, S.N.

2011-01-01

The main objective of the project is to investigate different types of molding rubbers used for investment casting. The level of shape complexity which can be achieved by using these rubber molds is also studied. It was almost impossible to make complex shapes molds using metal molds, in that cases rubber molds are very important because they arc flexible and give accurate and precise part dimensions. Turbine blades are hi-tech components with air-foil geometries that have close dimensional tolerances. They are made of super-alloys and manufactured by investment casting. The final blade profile depends upon the dimensional accuracy in each of the processing steps. In the present work experimental study for the production of high quality low cost castings of turbine blades using rubber molds and injected wax patterns is presented. Natural Rubber molds and wax patterns from these molds were made. Different types of molding rubbers were studied including natural rubber, silicone rubber and liquid silicone rubber. It was found that by using rubber molds we can make most complex shape with very less finishing required. The shrinkage was 12% as compared to original master pattern. Rubber molds were made using laboratory hot press. Three layers of rubber above and below the master pattern. After that vulcanization was done by giving temperature and pressure. (author)

Natural rubber: leather composites

OpenAIRE

Ravichandran,K.; Natchimuthu,N.

2005-01-01

Leather is a fibrous protein consisting of collagen in a three dimensionally crosslinked network. Chrome tanning of leather improves the appearance of leather but at the same time emits both solid and liquid chrome leather wastes. Scrap rubber recycling using untreated and neutralized leather fibrous particles in natural rubber has been studied. Vulcanization, mechanical, morphological and swelling properties of the natural rubber - scrap rubber composites containing neutralized leather have ...

NOFI oil Vee-Sweep and extension boom test at OHMSETT

International Nuclear Information System (INIS)

Bitting, K.R.; Vicedomine, J.

1993-01-01

The NOFI Vee-Sweep is an inflatable oil collection boom held in a V configuration by cross netting attached to the skirt of the boom. The NOFI 600S is an inflatable oil boom used to divert oil into the Vee-Sweep. The lower section of the 600S skirt consists of a feather net and a ballast chain. The booms are designed for open-ocean skimming where a skimmer is placed in the Vee-Sweep apex to remove the collected oil. During testing, the booms were preloaded with oil and towed in the OHMSETT tank at various speeds and wave conditions. Each boom was tested for its first and gross (continuous) oil loss speeds. The Vee-Sweep was also evaluated for wave performance, oil thickness vs tow speed, oil loss rate, and critical tow speed. Finally, a DESMI-250 oil skimmer was placed in the Vee-Sweep apex and oil loss tests were run while the skimmer was operating. During the critical tow speed testing, failures occurred due to apex submergence at ca 3.5 knots in calm water and short-crested waves, and 2.4 knots in harbor chop. The oil loss tests showed that the Vee-Sweep retains oil at speeds significantly higher than conventional booms. First oil loss speeds ranged from 1.3 knots in calm water to 1.0 knot in regular waves. The Vee-Sweep's high buoyancy/weight ratio gave it good wave performance in all conditions tested. The 600S oil loss speeds were higher than those of most conventional booms, and performance was better when the feather net was attached. 1 ref., 4 figs., 4 tabs

Environmental Pollution: Noise Pollution - Sonic Boom

Science.gov (United States)

1977-06-01

UNCLASSIFIED AD-A041 400 DDC/BIB-77/06 ENVIRONMENTAL POLLUTION NOISE POLLUTION SONIC BOOM A DDC BIBLIOGRAPHY DDC-TAS Cameron Station Alexandria, Va...rn7Sttio 658S-A041 400 4 TITLE xand r.VuhtlVlia) 2 TA i b- 1iblog ra ph y ENVIRONMENTAL POLLUTION : --. Apr-l IM59-Jul, 7NOISE POLLUTION -SONIC BOOM. 1,976...BIBLIOGRAPHY SEARCH CONTROL NO. /2OM09 AD- 769 970 20/1 1/3 DEFENSE UOCUMENTATION CENTER ALEXANDRIA VA ENVIRONMENTAL POLLUTION : NOISE POLLUTION

Rubber compounding and processing

CSIR Research Space (South Africa)

John, MJ

2014-06-01

Full Text Available This chapter presents an overview on the compounding and processing techniques of natural rubber compounds. The introductory portion deals with different types of rubbers and principles of rubber compounding. The primary and secondary fillers used...

Natural rubber: leather composites

Directory of Open Access Journals (Sweden)

K. Ravichandran

2005-06-01

Full Text Available Leather is a fibrous protein consisting of collagen in a three dimensionally crosslinked network. Chrome tanning of leather improves the appearance of leather but at the same time emits both solid and liquid chrome leather wastes. Scrap rubber recycling using untreated and neutralized leather fibrous particles in natural rubber has been studied. Vulcanization, mechanical, morphological and swelling properties of the natural rubber - scrap rubber composites containing neutralized leather have been discussed. Use of chrome leather particles has been found to improve the consumption of scrap rubber powder in natural rubber formulations. Polymer composites based on leather wastes as fillers are reported to be useful for many applications such as in construction materials, automobile interior moldings, heat and sound insulating boards, shoe soles, flooring materials and moldings with good anti-static properties, air permeability and good appearances.

Alternative Fuels Data Center: Hybrid and Electric Vehicles Boom Coast to

Science.gov (United States)

Coast Hybrid and Electric Vehicles Boom Coast to Coast to someone by E-mail Share Alternative Fuels Data Center: Hybrid and Electric Vehicles Boom Coast to Coast on Facebook Tweet about Alternative Fuels Data Center: Hybrid and Electric Vehicles Boom Coast to Coast on Twitter Bookmark Alternative

Evaluating a protocol for testing fire-resistant oil-spill containment boom

International Nuclear Information System (INIS)

Walton, W.D.; Twilley, W.H.; Hiltabrand, R.R.; Mullin, J.V.

1998-01-01

A series of experiments were conducted to evaluate a protocol for testing the ability of fire-resistant booms to withstand both fire and waves. Most response plans for in situ burning of oil at sea require the use of a fire-resistant boom to contain the oil during a burn. For this study, a wave tank was designed and constructed to assess the capabilities of a 15 m section of a boom subjected to a 5 m diameter fire with 0.15 m high waves. Five typical fire-resistant oil-spill containment booms were tested. The purpose of the project was to evaluate the test procedure, therefore the overall performance of the boom was not evaluated on a pass-fail criterion. The two most important aspects of the test method were repeatability and reproducibility. Some of the parameters tested included the effect of wind, waves, fire size, and fire duration. Methods to constrain the booms were also tested. 7 refs., 6 tabs., 7 figs

State of the art of sonic boom modeling

Science.gov (United States)

Plotkin, Kenneth J.

2002-01-01

Based on fundamental theory developed through the 1950s and 1960s, sonic boom modeling has evolved into practical tools. Over the past decade, there have been requirements for design tools for an advanced supersonic transport, and for tools for environmental assessment of various military and aerospace activities. This has resulted in a number of advances in the understanding of the physics of sonic booms, including shock wave rise times, propagation through turbulence, and blending sonic boom theory with modern computational fluid dynamics (CFD) aerodynamic design methods. This article reviews the early fundamental theory, recent advances in theory, and the application of these advances to practical models.

Rubber

Science.gov (United States)

Graves, D. F.

The word "rubber" immediately brings to mind materials that are highly flexible and will snap back to their original shape after being stretched. In this chapter a variety of materials are discussed that possess this odd characteristics. There will also be a discussion on the mechanism of this "elastic retractive force." Originally, rubber meant the gum collected from a tree growing in Brazil. The term "rubber" was coined for this material by the English chemist Joseph Priestley, who noted that it was effective for removing pencil marks from paper. Today, in addition to Priestley's natural product, many synthetic materials are made that possess these characteristics and many other properties. The common features of these materials are that they are made up of long-chain molecules that are amorphous (not crystalline), and the chains are above their glass transition temperature at room temperature.

Methodology for the Regulation of Boom Sprayers Operating in Circular Trajectories

Directory of Open Access Journals (Sweden)

Alfredo Serreta

2011-04-01

Full Text Available A methodology for the regulation of boom sprayers working in circular trajectories has been developed. In this type of trajectory, the areas of the plots of land treated by the outer nozzles of the boom are treated at reduced rates, and those treated by the inner nozzles are treated in excess. The goal of this study was to establish the methodology to determine the flow of the individual nozzles on the boom to guarantee that the dose of the product applied per surface unit is similar across the plot. This flow is a function of the position of the equipment (circular trajectory radius and of the displacement velocity such that the treatment applied per surface unit is uniform. GPS technology was proposed as a basis to establish the position and displacement velocity of the tractor. The viability of this methodology was simulated considering two circular plots with radii of 160 m and 310 m, using three sets of equipment with boom widths of 14.5, 24.5 and 29.5 m. Data showed as increasing boom widths produce bigger errors in the surface dose applied (L/m2. Error also increases with decreasing plot surface. As an example, considering the three boom widths of 14.5, 24.5 and 29.5 m working on a circular plot with a radius of 160 m, the percentage of surface with errors in the applied surface dose greater than 5% was 30%, 58% and 65% respectively. Considering a circular plot with radius of 310 m the same errors were 8%, 22% and 31%. To obtain a uniform superficial dose two sprayer regulation alternatives have been simulated considering a 14.5 m boom: the regulation of the pressure of each nozzle and the regulation of the pressure of each boom section. The viability of implementing the proposed methodology on commercial boom sprayers using GPS antennas to establish the position and displacement velocity of the tractor was justified with a field trial in which a self-guiding commercial GPS system was used along with three precision GPS systems located in

A comparative study of natural rubber modified with ground tire rubber of truck

OpenAIRE

Binti Haridan, Ili Liyana

2016-01-01

The recycling of waste rubber has considerable significance in term of environmental protection and energy conservation. Considering that most of the relevant literature is concerned with tire recycling, the aim of this work was to develop and characterize the elastomeric samples of natural rubber (NR) composites filled with ground tire rubber of truck (GTR) devulcanized by microwave (DGTR). The tire rubber was ground under ambient conditions and subjected to microwave exposure for 3, 5 and ...

Stress Analysis of Boom of Special Mobile Crane for Plain Region in Transmission Line

Science.gov (United States)

Qin, Jian; Shao, Tao; Chen, Jun; Wan, Jiancheng; Li, Zhonghuan; Jiang, Ming

2017-10-01

Basis of the boom force analysis of special mobile crane for plain region in transmission line, the load type of boom design is confirmed. According to the different combinations of boom sections, the composite pattern of the different boom length is obtained to suit the actual conditions of boom overlapping. The large deformation model is employed with FEM to simulate the stress distribution of boom, and the calculation results are checked. The performance curves of rated load with different arm length and different working range are obtained, which ensures the lifting capacity of special mobile crane meeting the requirement of tower erection of transmission line. The proposed FEM of boom of mobile crane would provide certain guiding and reference to the boom design.

Design of the De-Orbit Sail Boom Deployment Unit

Science.gov (United States)

Meyer, Sebastian; Hillebrandt, Martin; Straubel, Marco; Huhne, Christian

2014-06-01

The design of the De-Orbit Sail boom deployment unit is strongly driven by volume constraints, which are given by the cubesat container. Four CFRP (carbon fiber reinforced polymer) booms [4] with a cross-sectional shape of a double-omega and a length of 3.6 m are reeled on one spool in the center of the unit. The deployment of the four booms are controlled by an electric motor, which acts on the boom spool. Due to the volume limitation caused by the dimensions of the cubesat deployer the deployment unit has little room for the mechanisms components. With the aim to achieve a robust design, the deployment concept of the unit has greatly changed during the development process. The history of the design as well as the mechanisms are described. Additionally the results of the flight model testing are presented.

Natural Rubber Modification For Upper Layer Of Rubberized Asphalt Paving Block AS Shock Absorber

OpenAIRE

Nasruddin, Nasruddin

2017-01-01

The research of rubber compounding modification for upper layer of rubberized asphalt paving block as shock absorber using natural rubber, styrene butadiene rubber (SBR) as synthetic rubber, fly ash as filler and also vegetable oil as plasticizer has been conducted. The research design was varying the filler Si-69, fly ash and palm oil. The five formulas A, B, C, D, and E designed by varying the amount of Si-69 (48.5; 50.75; 53.00; 55.25; and 57.50) phr; coal fly ash (4.75, 7.00, 9.25, 11.50 ...

Fundamental studies on dynamic wear behavior of SBR rubber compounds modified by SBR rubber powder

OpenAIRE

Euchler, Eric; Heinrich, Gert; Michael, Hannes; Gehde, Michael; Stocek, Radek; Kratina, Ondrej; Kipscholl, Reinhold; Bunzel, Jörg-Michael; Saal, Wolfgang

2016-01-01

The aim of this study is focused on the experimental investigation of dynamic wear behavior of carbon black filled rubber compounds comprising pristine styrene butadiene rubber (SBR) together with incorporated SBR ground rubber (rubber powder). We also analyzed and described quantitatively the service conditions of some dynamically loaded rubber products, which are liable to wear (e.g. conveyor belts, tires). Beside the well-known standard test method to characterize wear resistance at steady...

Applications of flow visualization to the development of an innovative boom system

International Nuclear Information System (INIS)

Wong, K.F.V.; Wolek, A.

1996-01-01

A new oil retention boom system design was developed using a flow visualization technique. Hydrogen bubbles were generated on a fine wire cathode and placed in a stream of moving water with a strong light source to visualize the flow. Observations were made of the flow patterns around some basic shapes and booms modelled as cylinders with and without a skirt. The most effective system design had two booms with skirts in parallel with a submerged airfoil designed to cause the oil to separate and recirculate. Oil was allowed to flow above the airfoil into the recirculation region between the two floating booms. The new system is expected to outperform the conventional boom system only when flow velocity is high. Its most successful application would be in situations where flow is perpendicular to the length of the boom. 1 ref., 6 figs

Hardness measurements of silicon rubber and polyurethane rubber cured by ionizing radiation

International Nuclear Information System (INIS)

Basfar, A.A.

1995-01-01

This work investigates the hardness of both silicon rubber and polyurethane rubber cured by ionizing radiation. Shore A Hardness is used to characterize the subject elastomers in relation to the crosslinking process. Various formulations of both materials have been investigated in order to achieve the optimum cure conditions desired. A small amount of the curing agent has been incorporated in some formulations in order to reduce the required dose to achieve full cure conditions. Silicon rubber has shown improvements in hardness as absorbed dose is increased, whereas hardness remained constant over a range of absorbed doses for polyurethane rubber

The rubber tree genome reveals new insights into rubber production and species adaptation

OpenAIRE

Tang, Chaorong; Yang, Meng; Fang, Yongjun; Luo, Yingfeng; Gao, Shenghan; Xiao, Xiaohu; An, Zewei; Zhou, Binhui; Zhang, Bing; Tan, Xinyu; Yeang, Hoong Yeet; Qin, Yunxia; Yang, Jianghua; Lin, Qiang; Mei, Hailiang

2016-01-01

The Para rubber tree (Hevea brasiliensis) is an economically important tropical tree species that produces natural rubber, an essential industrial raw material. Here we present a high-quality genome assembly of this species (1.37 Gb, scaffold N50 = 1.28 Mb) that covers 93.8% of the genome (1.47 Gb) and harbours 43,792 predicted protein-coding genes. A striking expansion of the REF/SRPP (rubber elongation factor/small rubber particle protein) gene family and its divergence into several laticif...

Radiation-induced deterioration of natural rubber and isoprene rubber vulcanizates

International Nuclear Information System (INIS)

Kohjiya, Shinzo; Matsumura, Yasushige; Yamashita, Shinzo; Matsuyama, Tomochika; Yamaoka, Hitoshi.

1984-01-01

Natural rubber (NR) and isoprene rubber (IR) were cured by sulfur and accelerator to give rubber vulcanizates. Both vulcanizates were subject to solvent extraction to purify them, followed by the γ-ray irradiation in air at room temperature. The deterioration by γ-ray (0-20 Mrad) was investigated by the changes of tensile properties, hardness, swelling, and ATR-IR spectra. The tensile strength decreased much by a few Mrad irradiation, which is elucidated due to the difficulty of stretch-induced crystallization of polyisoprene after the irradiation. Modulus at 50 % elongation, network-chain density, and hardness did not show significant variation with the γ-ray dose. These irradiation results suggest both degradation and crosslinking occur comparably in the rubber vulcanizates and the regularity of polyisoprene chains may be somewhat randomized to prevent them from crystallizing on stretching. (author)

Rubber Reclamation

Science.gov (United States)

Williams, Kathryn R.

2007-01-01

The safety and health hazards related to recycling of used rubber, due to the scarcity and high price of virgin rubber are reported. Various threats like stagnant water pools trapped in tires leading to diseases and ignited tires, which become very difficult to extinguish and generating smoke that is extremely detrimental to the environment, have…

Effect of Recycled Rubber Particles and Silica on Tensile and Tear Properties of Natural Rubber Composites

Directory of Open Access Journals (Sweden)

Velu CHANDRAN

2016-05-01

Full Text Available Application of scrap rubber and worn out tires in natural rubber compounds has been studied. The scrap rubber can, however, be recycled and compounded with natural rubber and thus can be generated as a rubber composite. In this work, recycled rubber particles (RRP were prepared using pulverization process. Then, RRP was blended with natural rubber and silica compounds, and it was synthesized by two- roll mill and hydraulic press at specified operating conditions. The samples ranging from 0 to 40 phr of RRP loaded with silica were used as constant filler. The mechanical properties and morphological analysis were carried out. The results showed that tensile strength and elongation at break gradually decreased with increasing RRP loading in natural rubber and silica compounds. Tensile modulus went down at 10 phr of RRP and then showed an increasing trend. Hardness increased up to 30 phr of RRP and tear strength increased up to 20 phr of RRP. A comparative study was also carried out with virgin natural rubber vulcanizates. The incorporation of RRP and silica up to 20 phr in natural rubber did not lower the performance of rubber articles. Morphological studies revealed that better filler dispersion, interfacial adhesion, and cross link density could increase the tensile and tear strengths.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.7330

Shuttle sonic boom - Technology and predictions. [environmental impact

Science.gov (United States)

Holloway, P. F.; Wilhold, G. A.; Jones, J. H.; Garcia, F., Jr.; Hicks, R. M.

1973-01-01

Because the shuttle differs significantly in both geometric and operational characteristics from conventional supersonic aircraft, estimation of sonic boom characteristics required a new technology base. The prediction procedures thus developed are reviewed. Flight measurements obtained for both the ascent and entry phases of the Apollo 15 and 16 and for the ascent phase only of the Apollo 17 missions are presented which verify the techniques established for application to shuttle. Results of extensive analysis of the sonic boom overpressure characteristics completed to date are presented which indicate that this factor of the shuttle's environmental impact is predictable, localized, of short duration and acceptable. Efforts are continuing to define the shuttle sonic boom characteristics to a fine level of detail based on the final system design.

A ética de lado a lado: Fontes de notícias e jornalistas frente a frente

Directory of Open Access Journals (Sweden)

Francisco José Karam

2010-12-01

Full Text Available O artigo confronta a ética das fontes de notícias com a deontologia dos jornalistas. Os protagonistas são colocados frente a frente para apurar as responsabilidades, os conflitos, direitos, equívocos e, inclusive, as promiscuidades. Além do diálogo entre autores, confere-se nos manuais de redação e ética dos principais jornais brasileiros - Folha de S. Paulo, O Estado de S. Paulo, O Globo e Zero Hora - como tratam essa relação.

High-Speed Research: 1994 Sonic Boom Workshop. Configuration, Design, Analysis and Testing

Science.gov (United States)

McCurdy, David A. (Editor)

1999-01-01

The third High-Speed Research Sonic Boom Workshop was held at NASA Langley Research Center on June 1-3, 1994. The purpose of this workshop was to provide a forum for Government, industry, and university participants to present and discuss progress in their research. The workshop was organized into sessions dealing with atmospheric propagation; acceptability studies; and configuration design, and testing. Attendance at the workshop was by invitation only. The workshop proceedings include papers on design, analysis, and testing of low-boom high-speed civil transport configurations and experimental techniques for measuring sonic booms. Significant progress is noted in these areas in the time since the previous workshop a year earlier. The papers include preliminary results of sonic boom wind tunnel tests conducted during 1993 and 1994 on several low-boom designs. Results of a mission performance analysis of all low-boom designs are also included. Two experimental methods for measuring near-field signatures of airplanes in flight are reported.

USAF Flight Test Investigation of Focused Sonic Booms: Project Have Bears

Science.gov (United States)

Downing, Micah; Zamot, Noel; Moss, Chris; Morin, Daniel; Wolski, Ed; Chung, Sukhwan; Plotkin, Kenneth; Maglieri, Domenic

1996-01-01

Supersonic operations from military aircraft generate sonic booms that can affect people, animals and structures. A substantial experimental data base exists on sonic booms for aircraft in steady flight and confidence in the predictive techniques has been established. All the focus sonic boom data that are in existence today were collected during the 60's and 70's as part of the information base to the US Supersonic Transport program and the French Jericho studies for the Concorde. These experiments formed the data base to develop sonic boom propagation and prediction theories for focusing. There is a renewed interest in high-speed transports for civilian application. Moreover, today's fighter aircraft have better performance capabilities, and supersonic flights ars more common during air combat maneuvers. Most of the existing data on focus booms are related to high-speed civil operations such as transitional linear accelerations and mild turns. However, military aircraft operating in training areas perform more drastic maneuvers such as dives and high-g turns. An update and confirmation of USAF prediction capabilities is required to demonstrate the ability to predict and control sonic boom impacts, especially those produced by air combat maneuvers.

Laboratory hydro-mechanical characterisation of Boom Clay at Essen and Mol

International Nuclear Information System (INIS)

Deng, Y. F.; Tang, A. M.; Cui, Y. J.; Nguyen, X. P.; Li, X. L.; Wouters, L.

2011-01-01

Boom Clay has been selected as a potential host rock formation for the geological disposal of radioactive waste in Belgium. In the present work, the hydro-mechanical behaviour of Boom Clay samples from the borehole Essen-1 at a depth of 220-260 m and from HADES that is the underground rock laboratory at Mol in Belgium, at 223-m depth was investigated in the laboratory by performing low pressure odometer tests (vertical effective stress ranging from 0.05 to 3.2 MPa), high pressure odometer tests (vertical effective stress ranging from 0.125 to 32 MPa), isotropic consolidation tests (confining effective stress ranging from the in situ stress to 20 MPa) and triaxial shear tests. It has been observed that the mineralogy, geotechnical properties and hydro-mechanical behaviour of Boom Clay from Essen at 227-m, 240-m and 248-m depths are similar to that of Boom Clay from Mol. As in the case of Boom Clay at Mol, the failure envelope of Boom Clay at Essen in the p'- q plane is not linear. The slope of the portion beyond the pre-consolidation stress of Boom Clay from Essen is almost the same as that from Mol, suggesting a similar internal friction angle of about 13 deg. The compression curves (void index I v versus logarithm of vertical stress) beyond the pre-consolidation stress are the same for both samples from Mol and Essen, and situated between the intrinsic compression line (ICL) and the sedimentation compression line (SCL). The yield stress determined from odometer tests seems to be stress-path dependent and lower than the pre-consolidation stress. Thus determining the over-consolidation ratio (OCR) using the yield stress value would lead to an incorrect estimate. From a practical point view, the laboratory test results from Essen and their comparison with those from Mol provide important information regarding the transferability of knowledge on Boom Clay at different sites, taking into account the fact that most investigations have been carried out on Boom Clay at

Multilayer graphene rubber nanocomposites

Science.gov (United States)

Schartel, Bernhard; Frasca, Daniele; Schulze, Dietmar; Wachtendorf, Volker; Krafft, Bernd; Morys, Michael; Böhning, Martin; Rybak, Thomas

2016-05-01

Multilayer Graphene (MLG), a nanoparticle with a specific surface of BET = 250 m2/g and thus made of only approximately 10 graphene sheets, is proposed as a nanofiller for rubbers. When homogenously dispersed, it works at low loadings enabling the replacement of carbon black (CB), increase in efficiency, or reduction in filler concentration. Actually the appropriate preparation yielded nanocomposites in which just 3 phr are sufficient to significantly improve the rheological, curing and mechanical properties of different rubbers, as shown for Chlorine-Isobutylene-Isoprene Rubber (CIIR), Nitrile-Butadiene Rubber (NBR), Natural Rubber (NR), and Styrene-Butadiene Rubber (SBR). A mere 3 phr of MLG tripled the Young's modulus of CIIR, an effect equivalent to 20 phr of carbon black. Similar equivalents are observed for MLG/CB mixtures. MLG reduces gas permeability, increases thermal and electrical conductivities, and retards fire behavior. The later shown by the reduction in heat release rate in the cone calorimeter. The higher the nanofiller concentration is (3 phr, 5 phr, and 10 phr was investigated), the greater the improvement in the properties of the nanocomposites. Moreover, the MLG nanocomposites improve stability of mechanical properties against weathering. An increase in UV-absorption as well as a pronounced radical scavenging are proposed and were proved experimentally. To sum up, MLG is interesting as a multifunctional nanofiller and seems to be quite ready for rubber development.

Advances in rubber/halloysite nanotubes nanocomposites.

Science.gov (United States)

Jia, Zhixin; Guo, Baochun; Jia, Demin

2014-02-01

The research advances in rubber/halloysite nanotubes (rubber/HNTs) nanocomposites are reviewed. HNTs are environmentally-friendly natural nanomaterials, which could be used to prepare the rubber-based nanocomposites with high performance and low cost. Unmodified HNTs could be adopted to prepare the rubber/HNTs composites with improved mechanical properties, however, the rubber/HNTs nanocomposites with fine morphology and excellent properties were chiefly prepared with various modifiers by in situ mixing method. A series of rubber/HNTs nanocomposites containing several rubbers (SBR, NR, xSBR, NBR, PU) and different modifiers (ENR, RH, Si69, SA, MAA, ILs) have been investigated. The results showed that all the rubber/HNTs nanocomposites achieved strong interfacial interaction via interfacial covalent bonds, hydrogen bonds or multiple interactions, realized significantly improved dispersion of HNTs at nanoscale and exhibited excellent mechanical performances and other properties.

Electrospinning of PVC with natural rubber

Science.gov (United States)

Othman, Muhammad Hariz; Mohamed, Mahathir; Abdullah, Ibrahim

2013-11-01

Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber's mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber.

Electrospinning of PVC with natural rubber

International Nuclear Information System (INIS)

Othman, Muhammad Hariz; Abdullah, Ibrahim; Mohamed, Mahathir

2013-01-01

Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber’s mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber

Electrospinning of PVC with natural rubber

Energy Technology Data Exchange (ETDEWEB)

Othman, Muhammad Hariz; Abdullah, Ibrahim [Department of Chemistry, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Mohamed, Mahathir [Radiation Processing Technology Division (BTS), Malaysian Nuclear Agency, Bangi, 43000, Kajang (Malaysia)

2013-11-27

Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber’s mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber.

Degradation of blending vulcanized natural rubber and nitril rubber (NR/NBR) by dimethyl ether through variation of elastomer ratio

Science.gov (United States)

Saputra, A. H.; Juneva, S.; Sari, T. I.; Cifriadi, A.

2018-04-01

Dimethyl ether can cause degradation of the rubber material seal in some applications. In order to use of natural rubber in industry, research about a blending of natural rubber (NR) and nitrile rubber (NBR) to produce rubber to meet the standard seal material application were conducted. This study will observe the degradation mechanisms that occur in the blending natural rubber and nitrile rubber (NR/NBR) by dimethyl ether. Nitrile rubber types used in this study is medium quality nitrile rubber with 33% of acrylonitrile content (NBR33). The observed parameters are percent change in mass, mechanical properties and surface morphology. This study is limited to see the effect of variation vulcanized blending ratio (NR/NBR33) against to swelling. The increase of nitrile rubber (NBR33) ratio of blending rubber vulcanized can reduce the tensile strength and elongation. The best elastomer variation was obtained after comparing with the standard feasibility material of seal is rubber vulcanized blending (NR/NBR33) with ratio 40:60 NR: NBR.

Sonic boom predictions using a modified Euler code

Science.gov (United States)

Siclari, Michael J.

1992-04-01

The environmental impact of a next generation fleet of high-speed civil transports (HSCT) is of great concern in the evaluation of the commercial development of such a transport. One of the potential environmental impacts of a high speed civilian transport is the sonic boom generated by the aircraft and its effects on the population, wildlife, and structures in the vicinity of its flight path. If an HSCT aircraft is restricted from flying overland routes due to excessive booms, the commercial feasibility of such a venture may be questionable. NASA has taken the lead in evaluating and resolving the issues surrounding the development of a high speed civilian transport through its High-Speed Research Program (HSRP). The present paper discusses the usage of a Computational Fluid Dynamics (CFD) nonlinear code in predicting the pressure signature and ultimately the sonic boom generated by a high speed civilian transport. NASA had designed, built, and wind tunnel tested two low boom configurations for flight at Mach 2 and Mach 3. Experimental data was taken at several distances from these models up to a body length from the axis of the aircraft. The near field experimental data serves as a test bed for computational fluid dynamic codes in evaluating their accuracy and reliability for predicting the behavior of future HSCT designs. Sonic boom prediction methodology exists which is based on modified linear theory. These methods can be used reliably if near field signatures are available at distances from the aircraft where nonlinear and three dimensional effects have diminished in importance. Up to the present time, the only reliable method to obtain this data was via the wind tunnel with costly model construction and testing. It is the intent of the present paper to apply a modified three dimensional Euler code to predict the near field signatures of the two low boom configurations recently tested by NASA.

Biological Reclaiming of Recycled Rubber and Its Effect on Mechanical Properties of New Rubber Vulcanizates

Directory of Open Access Journals (Sweden)

Maryam Mansourirad

2014-12-01

Full Text Available Nowadays, due to environmental concerns, there has been great attention to recycling and reclaiming of tires. Different methods have been used for reclaiming or desulfurization of rubber. One of these methods, in which desulfurization of rubber happens with no damage to the polymer structure, is desulfurization by biological microorganisms. In this research the application and performance of thermophilic and sulfur oxidizing bacteria, Acidianus brierleyi for this purpose was investigated. Ground tire rubber was detoxified with organic solvents, and the optimum conditions for growing microorganisms in the existence of rubber powder in the shaker flasks were determined. In order to accelerate the process, the suitable conditions for growth of bacteria and desulfurization in the bioreactor were adopted. Fourier transfer infrared spectroscopy and scanning electron microscopy were employed to characterize desulfurization of bio-treated powder from bioreactor. The results indicated that morphological changes on powder surface and reduction of sulfur bonds have occurred. Samples from bioreactors, with and without bacteria and also untreated rubber powder were compounded with virgin styrene butadiene rubber. Tensile and dynamic properties were investigated using uni-direction tensile test and dynamic-mechanical-thermal analysis, respectively. Although some differences in dynamic-mechanical-thermal properties of samples pointed to stronger interaction between rubber matrix and treated rubber powder, no significant improvements in the mechanical properties of vulcanizates containing A.brierleyi-treated powder were observed. Low concentration of sulfur in rubber vulcanizates, chemical bonds of sulfur, and low efficiency of A. brierleyi in breaking sulfur bonds and reclaiming rubber were considered as the reasons for low efficiency of this treatment process.

Facts and features of radionuclide migration in Boom Clay

International Nuclear Information System (INIS)

De Regge, P.; Henrion, P.; Monsecour, M.; Put, M.

1988-01-01

The evolution which took place during ten years of research on the behaviour of radionuclides in Boom Clay is described. Initially, the Boom Clay was regarded as a chemically inert exchanger and the radiochemical research aimed at determining the distribution of cations between the clay and some liquid phases. The observation that Boom Clay deteriorates in contact with air and loses important intrinsic properties formed a major breakthrough in the research and led to a careful examination of the real in-situ conditions. Efforts devoted to the understanding of the chemical factors pertaining to the pH, the redox potential, the extent of the buffering capacity of FeS 2 and CaCO 3 in equilibrium with the interstitial aqueous phase are reviewed. Also emerging from the overall picture was the role of the organic material present in the Boom Clay. In contrast to the water percolating fractured formations which may not be in equilibrium with the rock, the interstitial aqueous phase is completely in equilibrium with Boom Clay mainly because of its low permeability and the large excesses of buffering components. As the retention mechanisms are better understood, a more coherent picture is obtained from distribution and diffusion experiments and the effects of consolidation are being investigated in detail. 23 refs.; 4 figs.; 3 tabs

Boom Booom Net Radio

DEFF Research Database (Denmark)

Grimshaw, Mark Nicholas; Yong, Louisa; Dobie, Ian

1999-01-01

of an existing Internet radio station; Boom Booom Net Radio. Whilst necessity dictates some use of technology-related terminology, wherever possible we have endeavoured to keep such jargon to a minimum and to either explain it in the text or to provide further explanation in the appended glossary....

Robotically enhanced rubber hand illusion.

Science.gov (United States)

Arata, Jumpei; Hattori, Masashi; Ichikawa, Shohei; Sakaguchi, Masamichi

2014-01-01

The rubber hand illusion is a well-known multisensory illusion. In brief, watching a rubber hand being stroked by a paintbrush while one's own unseen hand is synchronously stroked causes the rubber hand to be attributed to one's own body and to "feel like it's my hand." The rubber hand illusion is thought to be triggered by the synchronized tactile stimulation of both the subject's hand and the fake hand. To extend the conventional rubber hand illusion, we introduce robotic technology in the form of a master-slave telemanipulator. The developed one degree-of-freedom master-slave system consists of an exoskeleton master equipped with an optical encoder that is worn on the subject's index finger and a motor-actuated index finger on the rubber hand, which allows the subject to perform unilateral telemanipulation. The moving rubber hand illusion has been studied by several researchers in the past with mechanically connected rigs between the subject's body and the fake limb. The robotic instruments let us investigate the moving rubber hand illusion with less constraints, thus behaving closer to the classic rubber hand illusion. In addition, the temporal delay between the body and the fake limb can be precisely manipulated. The experimental results revealed that the robotic instruments significantly enhance the rubber hand illusion. The time delay is significantly correlated with the effect of the multisensory illusion, and the effect significantly decreased at time delays over 100 ms. These findings can potentially contribute to the investigations of neural mechanisms in the field of neuroscience and of master-slave systems in the field of robotics.

Structural characterization of rubber from jackfruit and euphorbia as a model of natural rubber.

Science.gov (United States)

Mekkriengkrai, Dararat; Ute, Koiichi; Swiezewska, Ewa; Chojnacki, Tadeusz; Tanaka, Yasuyuki; Sakdapipanich, Jitladda T

2004-01-01

A structural study of low molecular weight rubbers from Jackfruit (Artocarpus heterophyllus) and Painted spurge (Euphorbia heterophylla) was carried out as model compounds of natural rubber from Hevea brasiliensis. The rubber content of latex from Jackfruit was 0.4-0.7%, which is very low compared with that of 30-35% in the latex from Hevea tree. The rubber from Jackfruit latex was low molecular weight with narrow unimodal molecular weight distribution (MWD), whereas that obtained from E. heterophylla showed very broad MWD. The 1H and 13C NMR analyses showed that Jackfruit rubber consists of a dimethylallyl group and two trans-isoprene units connected to a long sequence of cis-isoprene units. The alpha-terminal group of Jackfruit rubber was presumed to be composed of a phosphate group based on the presence of 1H NMR signal at 4.08 ppm corresponding to the terminal =CH-CH2OP group.

Magnetic rubber inspection (MRI)

International Nuclear Information System (INIS)

Carro, L.

1997-01-01

Magnetic Rubber Inspection (MRI) was developed to inspect for small cracks and flaws encountered in high performance aircraft. A formula of very fine magnetic particles immersed in a room temperature curing rubber is catalysed and poured into dams (retainers) on the surface of the part to be inspected. Inducing a magnetic field then causes the particles to be drawn to discontinuities in the component under test. These indicating particles are held to the discontinuity by magnetic attraction, as the rubber cures. The solid rubber cast (Replica) is then removed and examined under a microscope for indicating lines of particle concentrations. 3 refs., 6 figs

Managing Credit Booms and Busts : A Pigouvian Taxation Approach

NARCIS (Netherlands)

Jeanne, O.; Korinek, A.

2010-01-01

We study a dynamic model in which the interaction between debt ac- cumulation and asset prices magni es credit booms and busts. We find that borrowers do not internalize these feedback e¤ects and therefore suf- fer from excessively large booms and busts in both credit flows and asset prices. We show

Comparative studies on the mechanical properties of natural rubber and natural rubber filled with multi-walled carbon nanotubes

Science.gov (United States)

Ismail, R.; Ibrahim, A.; Rusop, M.; Adnan, A.

2018-05-01

The present article compares the mechanical properties of natural rubber (NR) and carbon nanotubes (CNTs) filled natural rubber composites. Four types of nanocomposite specimens are fabricated with different MWCNT loadings: 0 wt% (pure natural rubber), 1 wt%, 3 wt%, and 5 wt%. The specimens are tested for their mechanical properties. It is observed that the tensile strength, hardness and elongation break of CNTs filled rubber composites are remarkably higher than that of raw rubber indicating the inherent reinforcing potential of CNTs. Percentage of the elongation at break of rubber CNTs composites is lower than that of raw rubber.

Inlet Trade Study for a Low-Boom Aircraft Demonstrator

Science.gov (United States)

Heath, Christopher M.; Slater, John W.; Rallabhandi, Sriram K.

2016-01-01

Propulsion integration for low-boom supersonic aircraft requires careful inlet selection, placement, and tailoring to achieve acceptable propulsive and aerodynamic performance, without compromising vehicle sonic boom loudness levels. In this investigation, an inward-turning streamline-traced and axisymmetric spike inlet are designed and independently installed on a conceptual low-boom supersonic demonstrator aircraft. The airframe was pre-shaped to achieve a target ground under-track loudness of 76.4 PLdB at cruise using an adjoint-based design optimization process. Aircraft and inlet performance characteristics were obtained by solution of the steady-state Reynolds-averaged Navier-Stokes equations. Isolated cruise inlet performance including total pressure recovery and distortion were computed and compared against installed inlet performance metrics. Evaluation of vehicle near-field pressure signatures, along with under- and off-track propagated loudness levels is also reported. Results indicate the integrated axisymmetric spike design offers higher inlet pressure recovery, lower fan distortion, and reduced sonic boom. The vehicle with streamline-traced inlet exhibits lower external wave drag, which translates to a higher lift-to-drag ratio and increased range capability.

The Effect of Gamma Irradiation on the Mechanical Properties of vulcanized Natural Rubber and Natural Rubber-Polyethylene Blends

International Nuclear Information System (INIS)

Sudradjat Iskandar

2008-01-01

To enhance the quality of vulcanized natural rubber and natural rubber-polyethylene blends, gamma irradiation has been done. The compound of natural rubber and natural rubber-polyethylene blends made by using roll mill machine. The mixed materials were antioxidant, anti ozon, plasticizer and vulcanisator. The natural rubber and natural rubber-polyethylene blends compound were vulcanizer and made a slab (film of sample) using hot and could press machine. The slabs produced were then gamma irradiated at irradiation dose of 75, 150 and 300 kGy. Before and after irradiation, the slab were characterized using strograph R1 machine. The results showed that the modulus 300 and hardness of vulcanized natural rubber and natural rubber-polyethylene blends were increasing; the tensile strength and tear strength were increasing to maximum level then decreasing with gamma irradiation, while the elongation at break was decreasing. The maximum tensile strength of vulcanized natural rubber and natural rubber-polyethylene blends were found at irradiation dose of 75 kGy. At the irradiation dose of 75 kGy, the tensile strength of vulcanized natural rubber increased from 17.6 MN/m 2 to 21.2 MN/m 2 , while the tensile strength of vulcanized natural rubber-polyethylene blends increased slightly from 18.7 MN/m 2 to 19.4 MN/m 2 . (author)

Vulcanization of Rubber

Indian Academy of Sciences (India)

Temperature 140 -180°C. Sulfur. 2-3 parts per. 100 parts of rubber (phr). Accelerator 0.5-1.0 phr. ZnO ... out an experiment, he spilt a mixture of rubber and sulfur with other ingredients on a hot .... both carbon-sulfur and sulfur-nitrogen bonds -.

Application of gamma irradiation for incorporation of rubber powder in the formulations of EPDM and natural rubber

International Nuclear Information System (INIS)

Kiyan, Ludmila Y.P.; Parra, Duclerc Fernandes; Lugao, Ademar Benevolo

2013-01-01

The objective of this work was to study the behavior of the recycling of rubber burrs in form of powder, of the rubber industry from EPDM rubber powder and natural rubber with SBR. The rubber powder was irradiated and reused in rubber artifacts formulations for classical vulcanization. The processed material was irradiated using a 60 Co source in doses of 50, 100, 150 and 200 kGy and a dose rate of 5 kGy s-1 at room temperature. The radiation created devulcanization active sites for subsequent integration of the material (rubber powder) in formulations of commercial use. The processes were compared and their products characterized by analytical methods of the physical properties such as strength and elongation. Satisfactory results were found, noting a major spin-off of EPDM chain demonstrated by increased elongation

Tribology Aspect of Rubber Shock Absorbers Development

Directory of Open Access Journals (Sweden)

M. Banić

2013-09-01

Full Text Available Rubber is a very flexible material with many desirable properties Which enable its broad use in engineering practice. Rubber or rubber-metal springs are widely used as anti-vibration or anti-shock components in technical systems. Rubber-metal springs are usually realized as a bonded assembly, however especially in shock absorbers, it is possible to realize free contacts between rubber and metal parts. In previous research it authors was observed that friction between rubber and metal in such case have a significant influence on the damping characteristics of shock absorber. This paper analyzes the development process of rubber or rubber-metal shock absorbers realized free contacts between the constitutive parts, starting from the design, construction, testing and operation, with special emphasis on the development of rubber-metal springs for the buffing and draw gear of railway vehicles.

Bust without boom.

Science.gov (United States)

Goldzieher, J W

2000-01-01

Just like injectables, oral contraceptives (OCs), including progestin-only ¿minipill¿ and ¿morning-after¿ pill regimens, have experienced a bust without a boom. Fear of political and religious backlash over emergency contraceptives containing estrogen and progestin prompted large companies not to market these regimens. Another major factor in the bust phase of OC use and acceptance has been a small coterie of English and American epidemiologists focused on the adverse effects of Ocs, including risks of thrombotic events, heart attacks, and strokes. The media played a crucial role in the bust phase of these OCs. In the UK, the alleged increase of cancer risk with pill use, which leaked before publication in London newspapers, resulted in 50,000 additional unintended pregnancies. Nevertheless, there is no doubt that boom-and-bust cycles will continue simply because many of the actors in this drama have too great a vested interest to desist. Groups involved in this field must recognize the hazards that come with the territory and be proactive, anticipatory, and well armed with facts--and get good with media access. Drug companies should think on a long-term basis the potential effects of leaving the field, as they have done, or shooting down competitive innovations.

Analysis of Nozzle Jet Plume Effects on Sonic Boom Signature

Science.gov (United States)

Bui, Trong

2010-01-01

An axisymmetric full Navier-Stokes computational fluid dynamics (CFD) study was conducted to examine nozzle exhaust jet plume effects on the sonic boom signature of a supersonic aircraft. A simplified axisymmetric nozzle geometry, representative of the nozzle on the NASA Dryden NF-15B Lift and Nozzle Change Effects on Tail Shock (LaNCETS) research airplane, was considered. The highly underexpanded nozzle flow is found to provide significantly more reduction in the tail shock strength in the sonic boom N-wave pressure signature than perfectly expanded and overexpanded nozzle flows. A tail shock train in the sonic boom signature, similar to what was observed in the LaNCETS flight data, is observed for the highly underexpanded nozzle flow. The CFD results provide a detailed description of the nozzle flow physics involved in the LaNCETS nozzle at different nozzle expansion conditions and help in interpreting LaNCETS flight data as well as in the eventual CFD analysis of a full LaNCETS aircraft. The current study also provided important information on proper modeling of the LaNCETS aircraft nozzle. The primary objective of the current CFD research effort was to support the LaNCETS flight research data analysis effort by studying the detailed nozzle exhaust jet plume s imperfect expansion effects on the sonic boom signature of a supersonic aircraft. Figure 1 illustrates the primary flow physics present in the interaction between the exhaust jet plume shock and the sonic boom coming off of an axisymmetric body in supersonic flight. The steeper tail shock from highly expanded jet plume reduces the dip of the sonic boom N-wave signature. A structured finite-volume compressible full Navier-Stokes CFD code was used in the current study. This approach is not limited by the simplifying assumptions inherent in previous sonic boom analysis efforts. Also, this study was the first known jet plume sonic boom CFD study in which the full viscous nozzle flow field was modeled, without

Lifetime Analysis of Rubber Gasket Composed of Methyl Vinyl Silicone Rubber with Low-Temperature Resistance

Directory of Open Access Journals (Sweden)

Young-Doo Kwon

2015-01-01

Full Text Available Most machines and instruments constantly require elastomeric materials like rubber for the purposes of shock absorption, noise attenuation, and sealing. The material properties and accurate lifetime prediction of rubber are closely related to the quality of machines, especially their durability and reliability. The properties of rubber-like elastomers are influenced by ambient conditions, such as temperature, environment, and mechanical load. Moreover, the initial properties of rubber gaskets must be sustained under working conditions to satisfy their required function. Because of its technical merits, as well as its low cost, the highly accelerated life test (HALT is used by many researchers to predict the long-term lifetime of rubber materials. Methyl vinyl silicone rubber (VMQ has recently been adopted to improve the lifetime of automobile radiator gaskets. A four-parameter method of determining the recovery ability of the gaskets was recently published, and two revised methods of obtaining the recovery were proposed for polyacrylate (ACM rubber. The recovery rate curves for VMQ were acquired using the successive zooming genetic algorithm (SZGA. The gasket lifetime for the target recovery (60% of a compressed gasket was computed somewhat differently depending on the selected regression model.

The role of linked phospholipids in the rubber-filler interaction in carbon nanotube (CNT) filler natural rubber (NR) composites

NARCIS (Netherlands)

Le, H.H.; Abhijeet, S.; Ilish, S.; Klehm, J.; Henning, S.; Beiner, M.; Sarkawi, S.S.; Dierkes, Wilma K.; Das, A.; Fischer, D.; Stöckelhuber, K.-W.; Wiessner, S.; Khatiwada, S.P.; Adhikari, R.; Pham, T.; Heinrich, G.; Radusch, H.-J.

2014-01-01

The aim of the present work is to evidence the role of the linked phospholipids of natural rubber (NR) in the rubber-carbon nanotube (CNT) interactions in rubber composites. Three rubbers namely NR, deproteinized NR (DPNR) and a synthetic rubber isoprene (IR) were used as matrix for CNTs. The

Silencing the lettuce homologs of small rubber particle protein does not influence natural rubber biosynthesis in lettuce (Lactuca sativa).

Science.gov (United States)

Chakrabarty, Romit; Qu, Yang; Ro, Dae-Kyun

2015-05-01

Natural rubber, cis-1,4-polyisoprene, is an important raw material in chemical industries, but its biosynthetic mechanism remains elusive. Natural rubber is known to be synthesized in rubber particles suspended in laticifer cells in the Brazilian rubber tree (Hevea brasiliensis). In the rubber tree, rubber elongation factor (REF) and its homolog, small rubber particle protein (SRPP), were found to be the most abundant proteins in rubber particles, and they have been implicated in natural rubber biosynthesis. As lettuce (Lactuca sativa) can synthesize natural rubber, we utilized this annual, transformable plant to examine in planta roles of the lettuce REF/SRPP homologs by RNA interference. Among eight lettuce REF/SRPP homologs identified, transcripts of two genes (LsSRPP4 and LsSRPP8) accounted for more than 90% of total transcripts of REF/SRPP homologs in lettuce latex. LsSRPP4 displays a typical primary protein sequence as other REF/SRPP, while LsSRPP8 is twice as long as LsSRPP4. These two major LsSRPP transcripts were individually and simultaneously silenced by RNA interference, and relative abundance, polymer molecular weight, and polydispersity of natural rubber were analyzed from the LsSRPP4- and LsSRPP8-silenced transgenic lettuce. Despite previous data suggesting the implications of REF/SRPP in natural rubber biosynthesis, qualitative and quantitative alterations of natural rubber could not be observed in transgenic lettuce lines. It is concluded that lettuce REF/SRPP homologs are not critically important proteins in natural rubber biosynthesis in lettuce. Copyright © 2014 Elsevier Ltd. All rights reserved.

Raw material boom in an industrial country. Rohstoffboom in einem Industrieland

Energy Technology Data Exchange (ETDEWEB)

Enders, K S

1984-01-01

First of all, a theoretical investigation is carried out to discover under which conditions a raw material boom displaces traditional sectors of industry, and which groups win and lose in the process. Subsequently, the peculiarities of the adaption process induced by the boom are analysed. Particular attention is paid to the possibility of transition (short-term) unemployment (Dutch disease). In conclusion, Norway's experiences in the oil and gas boom in the North Sea ar described and then compared with theoretical statements.

Flow distortion on boom mounted cup anemometers

DEFF Research Database (Denmark)

Lindelöw, Per Jonas Petter; Friis Pedersen, Troels; Gottschall, Julia

In this report we investigate on wind direction dependent errors in the measurement of the horizontal wind speed by boom mounted cup anemometers. The boom mounting on the studied lattice tower is performed according to IEC standard design rules, yet, larger deviations than predicted by flow models...... are observed. The errors on the measurements are likely caused by an underestimation of the flow distortions around the tower. In this paper an experimental method for deriving a correction formula and an in-field calibration is suggested. The method is based on measurements with two cup anemometers mounted...

Sheath-Based Rollable Lenticular-Shaped and Low-Stiction Composite Boom

Science.gov (United States)

Fernandez, Juan M. (Inventor)

2018-01-01

Various embodiments provide rollable and deployable composite booms that may be used in a wide range of applications both for space and terrestrial structural solutions. Various embodiment composite booms may be bistable, i.e. having a stable strain energy minimum in the coiled configuration as well as the in the deployed configuration. In various embodiments, a boom may be fabricated by aligning two independent tape-springs front-to-front encircled by a durable seamless polymer sleeve. The durable seamless polymer sleeve may allow the two tape-springs to slide past each other during the coiling/deployment process so as to reduce, e.g., minimize, shear and its derived problems.

Physico-mecha-nical properties of rubber seed shell carbon – filled natural rubber compounds

Directory of Open Access Journals (Sweden)

L.O. Ekebafe

2010-07-01

Full Text Available Samples of rubber seed shells were carbonized at varying temperatures (100, 200, 300, 400, 500, 600, 700 and 800 °C for three hours each and sieved through a 150 μm screen. The portion of the rubber seed shell carbon that passed through the screen was characterized in terms of loss on ignition, surface area, moisture content, pH, bulk density, and metal content and used in compounding natural rubber. The characterization shows that the pH, conductivity, loss on ignition and the surface area increases with the increases of the heating temperature, unlike the bulk density which decreases. The compound mixes were cured using the efficient vulcanization system. Cure characteristics of compounds and physico-mechanical properties of the vulcanisates were measured as a function of filler loading along with that of N330 carbon-black filled natural rubbers. The results showed that the cure times, scorch times and the torque gradually increased, with increasing the filler content for rubber seed shell carbon-filled natural rubber, with the filler obtained at carbonizing temperature of 600 °C tending to show optimum cure indices. The physicomechanical properties of the vulcanisates increase with filler loading. The reinforcing potential of the carbonized rubber seed shell carbon was found to increase markedly for the filler obtained at the temperature range of 500-600 °C and then decreases with further increase in temperature.

Constructing better roads with asphalt rubber

Directory of Open Access Journals (Sweden)

Pais Jorge C.

2015-12-01

Full Text Available Brazilians mixtures containing asphalt rubber were evaluated by mechanical laboratory tests. A conventional mixture with asphalt CAP-50/70 was produced as a mixture control. With the aim of compare the Brazilians mixtures performance, a Portuguese asphalt rubber mixture was tested as well. The testing set involved the determination of the mechanical properties, fatigue and permanent deformation, of asphalt rubber produced by wet process through two different systems: continuous blend and terminal blend. The asphalt rubber morphology was evaluated in order to determine the compatibility of the systems. The asphalt rubber mixtures exhibit good resistance to permanent deformation and prolonged fatigue life in relation to mixture control. Therefore it is concluded that the application of asphalt rubber alters the characteristics of asphalt mixture in a very beneficial way.

Rubber modification of asphalt binders and mixes

Energy Technology Data Exchange (ETDEWEB)

Morrison, G.; Hesp, S.A.M. [Queen`s Univ., Kingston, ON (Canada). Dept. of Chemistry

1995-12-31

The physical properties of asphalt binders and concrete, modified with waste rubber tire, were examined. In an experiment designed to address the concern of waste disposal of scrap rubber, a control asphalt, devulcanized rubber modified asphalt and a crumb rubber modified asphalt were used to make asphalt concrete mixes. The three mixes were subjected to a thermal stress test to determine their low temperature fracture temperatures and strengths. Results were discussed in terms of the binder material used. At high service temperatures, the addition of 10% devulcanized rubber was found to have no beneficial effect, whereas the addition of 10% 80 mesh crumb rubber produced a modest improvement in performance. At low temperatures, the addition of devulcanized rubber produced increased resistance to cracking up to 90%. The addition of 10% 80 mesh crumb rubber increased fracture toughness by a factor of 3.3 times. 12 refs., 3 tabs.

Solubility Study of Curatives in Various Rubbers

NARCIS (Netherlands)

Guo, R.; Talma, Auke; Datta, Rabin; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

2008-01-01

The previous works on solubility of curatives in rubbers were mainly carried out in natural rubber. Not too much information available on dissimilar rubbers and this is important because most of the compounds today are blends of dissimilar rubbers. Although solubility can be expected to certain

Nitrile rubber and carboxylated nitrile rubber resistance to soybean biodiesel

OpenAIRE

Felipe Nunes Linhares; Cléverson Fernandes Senra Gabriel; Ana Maria Furtado de Sousa; Marcia Christina Amorim Moreira Leite; Cristina Russi Guimarães Furtado

2018-01-01

Abstract Biodiesel has been considered a suitable substitute for petroleum diesel, but their chemical composition differs greatly. For this reason, biodiesel interacts differently than petroleum diesel with various materials, including rubbers. Therefore, the resistance of some elastomers should be thoroughly evaluated, specifically those which are commonly used in automotive industry. Nitrile rubber (NBR) is widely used to produce vehicular parts that are constantly in contact with fuels. T...

QENS investigation of filled rubbers

CERN Document Server

Triolo, A; Desmedt, A; Pieper, J K; Lo Celso, F; Triolo, R; Negroni, F; Arrighi, V; Qian, H; Frick, B

2002-01-01

The polymer segmental dynamics is investigated in a series of silica-filled rubbers. The presence of inert fillers in polymers greatly affects the mechanical and physical performance of the final materials. For example, silica has been proposed as a reinforcing agent of elastomers in tire production. Results from quasielastic neutron scattering and Dynamic Mechanical Thermal Analysis (DMTA) measurements are presented on styrene-ran-butadiene rubber filled with silica. A clear indication is obtained of the existence of a bimodal dynamics, which can be rationalized in terms of the relaxation of bulk rubber and the much slower relaxation of the rubber adsorbed on the filler surface. (orig.)

Carboxy terminated rubber based on natural rubber grafted with acid anhydrides and its adhesion properties

International Nuclear Information System (INIS)

Klinpituksa, P; Kongkalai, P; Kaesaman, A

2014-01-01

The chemical modification of natural rubber by grafting of various polar functional molecules is an essential method, improving the versatility of rubber in applications. This research investigated the preparation of natural rubber-graft-citraconic anhydride (NR-g-CCA), natural rubber-graft-itaconic anhydride (NR-g-ICA), and natural rubber-graft-maleic anhydride (NR-g-MA), with the anhydrides grafted to natural rubber in toluene using benzoyl peroxide as an initiator. Variations of monomer content, initiator content, temperature and reaction time of the grafting copolymerization were investigated. The maximum degrees of grafting were 1.06% for NR-g-CCA, 4.66% for NR-g-ICA, and 5.03% for NR-g-MA, reached using 10 phr citraconic anhydride, 10 phr of itaconic anhydride, or 8 phr of maleic anhydride, 3 phr benzoyl peroxide, at 85, 80 and 80°C for 2, 2 and 3 hrs, respectively. Solvent-based wood adhesives were formulated from these copolymers with various contents of wood resin in the range 10-40 phr. The maximal 289 N/in cleavage peel and 245.7 KPa shear strength for NR-g-MA (5.03% grafting) were obtained at 40 phr wood resin

Dynamic simulation of a planar flexible boom for tokamak in-vessel operations

International Nuclear Information System (INIS)

Ambrosino, G.; Celentano, G.; Garofalo, F.; Maisonnier, D.

1991-01-01

In this paper we present a dynamic model for the analysis of the vibrations of a planar articulated flexible boom to be used for tokamak in-vessel maintenance operations. The peculiarity of the mechanical structure of the boom enables us to consider separately the oscillations in the horizontal and vertical planes so that two separate models can be constructed for describing these phenomena. The results of simulations based on booms like that proposed for NET in-vessel operations are presented. (orig.)

Hyundai plans rubber unit despite overcapacity

International Nuclear Information System (INIS)

Hyoungjin Kim.

1993-01-01

Despite the oversupply of synthetic rubber in South Korea, the government has granted approval to Hyundai Petrochemical (Seoul) to build the country's second synthetic rubber unit, to be located alongside its petrochemical complex at Daesan. The plant is due for startup during second-half 1995, when the local market is expected to be in better balance. Hyundai will use Goodyear Tire ampersand Rubber technology for the plant, which will have annual capacities for 40,000 m.t. of polybutadiene rubber (BR), 30,000 m.t. of styrene butadiene rubber (SBR) and 12,000 m.t. of nitrile rubber (NBR). Styrene and butadiene requirements will be met from Hyundai's own production at Daesan. The current local producer of synthetic rubber is Korea Kumho Petrochemicals (Seoul), which has annual capacities for 150,000 m.t. of SBR, 95,000 m.t. of BR, and 10,000 m.t. of NBR. Korean SBR demand is about 141,000 m.t./year but is expected to increase to 161,000 m.t./year by 1996 and reach 194,000 m.t./year by the end of the decade

Static friction in rubber-metal contacts with application to rubber pad forming processes

NARCIS (Netherlands)

Deladi, E.L.

2006-01-01

A static friction model suitable for rubber-metal contact is presented in this dissertation. In introduction, the motivation and the aims of the research are introduced together with the background regarding the related industrial application, which is the rubber pad forming process.

Studies on the increased heat effect within the rubber tree rows of man-made rubber-tea community

International Nuclear Information System (INIS)

Ma Youxin

1994-01-01

Differences in the various components of thermal balance and the microclimatic factors within lower layers of rubber tree rows between a man-made rubber-tea community(RTC)and a pure rubber garden(PRG)in the coldest month were studied in Xishuangbanna,Yun-nan province

The NET articulated boom: Preliminary investigations and justification for a full scale prototype

International Nuclear Information System (INIS)

Suppan, A.

1990-12-01

The articulated boom system is the favourite in-vessel handling system for NET which will be used to maintain or replace in-vessel components during short term interventions. The testbed EDITH is the prototype of this system and is the logical step between the proof of principle of the system, which is already performed by the JET articulated boom, and the operational equipment for NET. EDITH is required to demonstrate that maintenance of plasma facing components can be carried out with the anticipated reliability and time. To achieve this aim EDITH is based on the experience of the JET boom and will be constructed in full scale, supplemented by a full scale mock-up. A further goal of EDITH is to allow the testing of boom components and subassemblies. The results of preliminary investigations for the boom are summarized, the need of the testbed EDITH and a full scale mock-up is discussed and both EDITH and the mock-up are described. (orig.) [de

Radiation induced graft copolymerization of acrylonitrile on natural rubber

International Nuclear Information System (INIS)

Claramma, N.M.; Mathew, N.M.; Thomas, E.V.

1989-01-01

Acrylonitrile graft natural rubber was prepared by initiating the polymerization of acrylonitrile in natural rubber field latex using γ-rays. The reaction was carried out at different rubber-monomer concentrations and the properties of the modified rubbers were compared with those of natural rubber and nitrile rubber. (author)

Biodiversity in rubber agroforests

NARCIS (Netherlands)

Beukema, Hendrien

2013-01-01

Jungle rubber tuinen zijn extensieve rubber agroforests die qua structuur op secundaire bossen lijken, en waarin wilde soorten door de boer worden getolereerd. Met het verdwijnen van het laaglandregenwoud rijst de vraag of de begroeiing die ervoor in de plaats komt een aantal kenmerken en functies

Enzymatic synthesis of rubber polymer in Hevea brasiliensis

Energy Technology Data Exchange (ETDEWEB)

Tang, F.; Hu, S.; Benedict, C.R. (Texas A and M Univ., College Station (United States))

1991-05-01

Light and Dennis purified serum soluble rubber transferase from Hevea latex to homogeneity. Prenyl transferase co-purified with rubber transferase. In the absence of washed rubber particles (WRP) the prenyl transferase catalyzed the formation of trans FPP from DMAPP and IPP. In the presence of WRP the transferase catalyzed cis additions of IPP to pre-existing rubber chains. Control mixtures of WRP, Mg{sup 2+} and FPP were not included to test for the contributions of the bound rubber transferase on WRP to the incorporation of IPP into polyisoprene. Bound rubber transferase catalyzes the repetitive addition of IPP to allylic-PP starter molecules to form polyisoprene. The order of utilization of allylic-PP starters was GGPP > FPP > GPP > DMAPP. The authors have shown that the polyisoprene enzymatically synthesized on WRP is a bimodal polymer consisting of different mol wt rubber chains similar to the polymeric characteristics of natural rubber. The bound rubber transferase was solubilized with Chaps and purified on DEAE-cellulose. The polymerization reaction catalyzed by the purified preparation showed a 98% requirement for pre-existing rubber chains. Results suggest that the prenyl transferase from Hevea serum may be part of the polymer starter system furnishing allylic-PP for the bound rubber transferase.

MODEL CORRELATION STUDY OF A RETRACTABLE BOOM FOR A SOLAR SAIL SPACECRAFT

Science.gov (United States)

Adetona, O.; Keel, L. H.; Oakley, J. D.; Kappus, K.; Whorton, M. S.; Kim, Y. K.; Rakpczy, J. M.

2005-01-01

To realize design concepts, predict dynamic behavior and develop appropriate control strategies for high performance operation of a solar-sail spacecraft, we developed a simple analytical model that represents dynamic behavior of spacecraft with various sizes. Since motion of the vehicle is dominated by retractable booms that support the structure, our study concentrates on developing and validating a dynamic model of a long retractable boom. Extensive tests with various configurations were conducted for the 30 Meter, light-weight, retractable, lattice boom at NASA MSFC that is structurally and dynamically similar to those of a solar-sail spacecraft currently under construction. Experimental data were then compared with the corresponding response of the analytical model. Though mixed results were obtained, the analytical model emulates several key characteristics of the boom. The paper concludes with a detailed discussion of issues observed during the study.

Performance of self-compacting rubberized concrete

Directory of Open Access Journals (Sweden)

Hamza Bensaci

2018-01-01

Full Text Available Used tyre rubber wastes present a serious environmental problem of pollution and storage. The recycling of this waste in the industry of construction could be an appropriate solution to produce an eco-concrete and could contribute to the improvement of some of its properties. This paper aims to study the possibility of using tyre rubber waste as fine aggregate replacement in self-compacting concrete (SCC. Fines rubber particles of 0-2 mm of waste tyres were added SCC mixtures as a partial substitution of the total volume of sand at different percentages (5, 10, 15, 20 and 30%. The influence of fines rubber of used tyres on fresh and hardened properties of the SCC was investigated. The fresh properties of SCC were performed by using slump-flow, T50 flow time, L-box, V-funnel and segregation resistance tests. Characteristics of the hardened state were obtained by compressive strength and thermal conductivity. The experimental results showed that the inclusion of fines rubber in SCC decreases the workability, reduced its passing capacity and increases the possibility of blocking. A decrease in compressive strength is observed with the increase in rubber content. On the other hand, the incorporation of the rubber fines aggregates enhances in a remarkably way the thermal conductivity.

Icelandic boom and bust - Immigration and the housing market

OpenAIRE

Lúðvík Elíasson

2014-01-01

Possible explanations for the rapid increase in house prices and housing investment in Iceland between 2004 and 2007 and the subsequent market crash are studied. The boom was driven in part by banking liberalisation, international financial conditions, and domestic policies. A simple demand and supply model, based on the study by Elíasson and Pétursson (2009), is fitted to data through the recent boom-bust period. The model is remarkably robust through the cycle despite its unprecedented ampl...

Chlorinated rubbers with advanced properties for tire industry

Science.gov (United States)

Mikhaylov, I. A.; Sukhareva, K. V.; Andriasyan, Yu. O.; Popov, A. A.

2017-12-01

The paper investigates the production and processing of halide-modified chlorinated rubbers, such as isobutylene isoprene rubber and ethylene-propylene-diene-monomer rubber (IIR and EPDM), which are perspective in terms of application in rubber industry. Prospects for their production and application are determined by the specific properties of these rubbers (low gas permeability of IIR, high heat and ozone resistance of EPDM). These properties are governed by the structure of both initial IIR and EPDM and chlorinated rubbers (ChIIR and ChEPDM). A new alternative technology of obtaining chlorinated elastomers based on solid-phase mechanochemical halide modification is proposed. Novel chlorinated polyolefin rubbers obtained by the developed technology show good technological properties under industrial production conditions due to enhanced covulcanization.

Production and performance of desulfurized rubber asphalt binder

Directory of Open Access Journals (Sweden)

Yanping Sheng

2017-05-01

Full Text Available Asphalt rubber binder typically exhibits disadvantages like segregation and high viscosity; however, this can be improved by the incorporation of desulfurized rubber powder. This study examined the swelling principle of desulfurized rubber asphalt (DRA. In addition, it evaluated the performance of DRA fabricated with various rubber powder contents under different shear conditions and development time. Superpave binders tests, including Brookfield viscosity, dynamic shear rheometer (DSR and bending beam rheometer (BBR tests, were applied on three control binders (i.e., neat, 20 mesh asphalt rubber binder, 40 mesh asphalt rubber binder and a DRA binder. Binder testing results indicated that rubber powder swelled into the base binder and resulted in enhanced stability. Optimum performance of the DRA binder was achieved by adding 20% (by weight of rubber powder into the base binder at shear rate, shear temperature, shear time and development time of 7000 r/min, 170 °C, 60 min and 45 min, respectively. Modified ranges of production conditions were also provided to widen the application of DRA in field construction. It appeared that DRA binder benefited from the recovered plasticity and viscosity of the rubber and consequently, exhibited superior performance over the neat and conventional asphalt rubber binders. Preliminary mixture evaluation was also conducted and the DRA binder was found to significantly improve the mixture resistance to permanent deformation and water damage. Overall, the DAR binder is encouraged to be used as a modified binder for flexible pavements. Keywords: Desulfurized rubber asphalt, Swelling model, Production process, Asphalt performance, Rubber asphalt

Chemical modifications of liquid natural rubber

Science.gov (United States)

Azhar, Nur Hanis Adila; Rasid, Hamizah Md; Yusoff, Siti Fairus M.

2016-11-01

Liquid natural rubber (LNR) was synthesized via photosentisized degradation of natural rubber (NR). LNR was modified into epoxidized liquid natural rubber (LENR) and hydroxylated liquid natural rubber (LNR-OH) using Na2WO4/CH3COOH/H2O2 catalytic system. Chemical structures of LNR and modified LNRs were characterized using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and 1H Nuclear Magnetic Resonance (NMR) spectroscopies. Integration of 1H NMR was used to calculate the epoxy content (%) of LENR. 1H NMR detected the formation of LNR-OH after prolonged heating and increased of catalyst in oxidation reaction.

The Cyclization of natural rubber

International Nuclear Information System (INIS)

Mirzataheri, M.

2000-01-01

The effect of solvent, temperature, time, weight percent of catalyst on the rate and mechanism of cyclization of natural rubber was studied in toluene and xylene solutions having tin tetra chloride catalyst (SnCl 4 ). Iodo metric titration show, with 8% SnCl 4 (based on polymer weight) cyclization occurs, leaving 27.4% of the total unsaturation. Infrared spectra of cyclized natural rubber show decreased absorption intensity at 840 and 780 cm -1 which are characteristic bands of the linear polymer and the appearance of absorption band at 890 cm -1 as cycles were formed. By using this chemical modification, natural rubber is transformed into a resinous thermoplastic, hard, non rubbery cyclized material with much less unsaturation than the original rubber, which could find commercial applications ad adhesives, printing inks, industrial and ship paints

Presence and evolution of natural organic matter in the boom clay

International Nuclear Information System (INIS)

Van Geet, M.; Deniau, I.; Largeau, C.; Bruggeman, C.; Maes, A.; Dierckx, A.

2004-01-01

Because of its very low hydraulic conductivity, reducing conditions, slightly alkaline pH, high specific surface, high cation exchange capacity and high plasticity, the Boom Clay is studied as a reference host formation for the deep disposal of high-level long-lived radioactive waste (NIRAS/ONDRAF, 1989). However, Boom Clay also contains up to 5% wt. of organic matter (OM). As radionuclides can form complexes with this organic matter, a detailed characterisation and knowledge of the evolution of the organic matter is necessary. An overview of the characteristics of the organic matter present in Boom Clay is given by Van Geet et al., (2003). The solid phase OM can be up to 5%. The dissolved OM fraction is around 200 mg C per liter of Boom Clay pore water. Both kinds of OM will be discussed. Concerning the solid phase OM the focus will be on the past evolution and its possible future evolution due to a thermal stress. For the dissolved OM, the focus will be on its origin. (author)

Use of rubber crumbs in cement concrete

Science.gov (United States)

Longvinenko, A. A.

2018-03-01

Rubber crumb obtained from worn out tires has been increasingly used over the last 15-20 years, especially in manufacture of asphalt and cement concrete mixtures. This review pays principal attention to application of the rubber crumb to cement concrete mixtures. Use of the rubber crumb in cement concrete is not as successful as in asphalt concrete mixtures, due to incompatibility problems linked to chemical composition and a significant difference in rigidity between the rubber crumb and concrete mixture aggregates. Different methods are proposed and studied to mitigate the adverse influence and increase the beneficial effects of the rubber crumb when added to cement concrete.

Natural rubber (NR) biosynthesis: perspectives from polymer chemistry

Energy Technology Data Exchange (ETDEWEB)

Barkakaty, Balaka [ORNL

2014-01-01

Natural rubber is an important strategic raw material for manufacturing a wide variety of industrial products. There are at least 2,500 different latex-producing plant species; however, only Hevea brasiliensis (the Brazilian rubber tree) is a commercial source. The chemical structure of natural rubber is cis-1,4-polyisoprene, but the exact structure of the head and end groups remains unknown. Since synthetic cis-1,4-polyisoprenes cannot match the superior properties of natural rubber, understanding the chemistry behind the biosynthetic process is key to finding a possible replacement. T his chapter summarizes our current understandings from the perspective of a polymer scientist by comparing synthetic polyisoprenes to natural rubber. The chapter also highlights biomimetic polymerization, research towards a synthetic match of natural rubber and the role of natural rubber in health care.

Modeling and simulation of the agricultural sprayer boom leveling system

KAUST Repository

Sun, Jian

2011-01-01

According to the agricultural precision requirements, the distance from sprayer nozzles to the corps should be kept between 50 cm to 70 cm. The sprayer boom also needs to be kept parallel to the field during the application process. Thus we can guarantee the quality of the chemical droplets distribution on the crops. In this paper we design a sprayer boom leveling system for agricultural sprayer vehicles combined with a four-rod linkage self-leveling suspension and electro-hydraulic auto-leveling system. The dynamic analysis shows that the suspension can realize an excellent self-leveling in a comparative small inclination range. In addition we build compensation controller for the electro-hydraulic system based on the mathematical model. With simulations we can optimize the performance of this controller to make sure a fast leveling response to the inclined sprayer boom. © 2011 IEEE.

Amphiphilic semi-interpenetrating polymer networks using pulverized rubber

Science.gov (United States)

Shahidi, Nima

Scrap rubber materials provide a significant challenge to either reuse or safe disposal. Every year, millions of tires are discarded to landfills in the United States, consuming a staggering amount of land space, creating a high risk for large fires, breeding mosquitoes that spread diseases, and wasting the planet's natural resources. This situation cannot be sustained. The challenge of reusing scrap rubber materials is mainly due to the crosslinked structure of vulcanized rubber that prevent them from melting and further processing for reuse. The most feasible recycling approach is believed to be a process in which the vulcanized rubber is first pulverized into a fine powder and then incorporated into new products. The production of fine rubber particles is generally accomplished through the use of a cryogenic process that is costly. Therefore, development of a cost effective technology that utilizes a large quantity of the scrap rubber materials to produce high value added materials is an essential element in maintaining a sustainable solution to rubber recycling. In this research, a cost effective pulverization process, solid state shear extrusion (SSSE), was modified and used for continuous pulverization of the rubber into fine particles. In the modified SSSE process, pulverization takes place at high compressive shear forces and a controlled temperature. Furthermore, an innovative particle modification process was developed to enhance the chemical structure and surface properties of the rubber particles for manufacturing of high value added products. Modification of rubber particles was accomplished through the polymerization of a hydrophilic monomer mixture within the intermolecular structure of the hydrophobic rubber particles. The resulting composite particles are considered as amphiphilic particulate phase semi-interpenetrating polymer networks (PPSIPNs). The modified rubber particles are water dispersible and suitable for use in a variety of aqueous media

Characterization of the natural rubber from new rubber tree clones of PB 300 series

International Nuclear Information System (INIS)

Silva, Maycon J.; Spinelli, Rafaela O.; Moreno, Rogerio M.B.; Mattoso, Luiz H.C.; Martins, Maria Alice; Scaloppi Junior, Erivaldo J.

2015-01-01

The natural rubber (NR) is present in more than 2500 species of plants, being the Hevea brasiliensis the most commercially exploited. It is a raw material of great importance to the Brazilian economy, but the country faces a production's deficit, having to import about 60% of its consumption. In this work , the latex obtained from rubber tree of new clones of PB series 300 (PB 311, PB 312, PB 314 , PB 326, PB 346 and PB 350 ) and RRIM 600 (control) were characterized by dry rubber content (DRC), total solids content, distribution of particle size, Zeta potential, thermogravimetry, differential scanning calorimetry, infrared in the spectroscopy (FTIR), nuclear magnetic resonance (NMR) and technological properties. The DRC values ranged from 33% to 40%, and total solids of 38% to 44%. All of the clones showed average particle diameter between 180.0 to 192.1 nm, excluding clones PB 326 and PB 346 with 150.0 nm and 157.9 nm, respectively. The NMR spectra and FTIR showed that the structure of the natural rubber from all clones studied is cis -1,4- polyisoprene. Natural rubber from the new clones showed good thermal stability up to 285 °C and glass transition temperature of -64 °C. (author)

SUPPLY-CHAIN OF NATURAL RUBBER IN INDONESIA

Directory of Open Access Journals (Sweden)

Bustanul Arifin

2011-08-01

Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 st1\\:*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} The study examines the supply chain of natural rubber production in Indonesia and assessing the transmission of prices to rubber growers and provides recommendations for a suitable scheme that would help to ensure high production standards and a sustainable return for natural rubber production.  The frameworks to examine the performance of supply chain of rubber marketing rely mostly on the efficiency level of marketing system of natural rubbers, including the value chain principles in marketing margin, and revealed price transmission from consumers to growers. The results show that the roles of subdistrict middlemen are extremely crucial in moving up the slabs from the village level to urban areas, where trader-brokers are expecting the slabs to be forwarded directly to crumb-rubber factories.  Changes in world price, hence the profits being accumulated by traders and rubber factories, are not transmitted properly to rubber farmers and/or sharetappers. Information asymmetry, the access over price information, and immediate response of rubber growers to the change in world price could explain this non-cointegration in price data between growers and exporters.  In the near future, the policy reforms in supply chain of natural rubber marketing in Indonesia should carefully address these issues in a more comprehensive manner.  Finally, in order to contribute to the positive environmental and social benefits, the major challenge for natural rubber

75 FR 38119 - Polychloroprene Rubber From Japan

Science.gov (United States)

2010-07-01

... Rubber From Japan AGENCY: United States International Trade Commission. ACTION: Institution of a five-year review concerning the antidumping duty finding on polychloroprene rubber from Japan. SUMMARY: The... on polychloroprene rubber from Japan would be likely to lead to continuation or recurrence of...

A summary of the lateral cutoff analysis and results from NASA's Farfield Investigation of No-boom Thresholds

Science.gov (United States)

Cliatt, Larry J.; Hill, Michael A.; Haering, Edward A.; Arnac, Sarah R.

2015-10-01

In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, NASA, in partnership with other industry organizations, conducted a flight research experiment to analyze acoustic propagation at the lateral edge of the sonic boom carpet. The name of the effort was the Farfield Investigation of No-boom Thresholds (FaINT). The research from FaINT determined an appropriate metric for sonic boom waveforms in the transition and shadow zones called Perceived Sound Exposure Level, established a value of 65 dB as a limit for the acoustic lateral extent of a sonic boom's noise region, analyzed change in sonic boom levels near lateral cutoff, and compared between real sonic boom measurements and numerical predictions.

Sobre o Boom e outras onomatopeias literárias

OpenAIRE

Londoño, Jorge Iván Parra

2016-01-01

Este artículo trata de examinar los alcances literarios del llamado Boom latinoamericano, a medio siglo de su estallido, las cuatro obras más representativas y sus respectivos autores, además de proponer un quinto autor, según la invitación que hiciera en su momento el crítico Ángel Rama. Por otro lado, evalua la respuesta literaria por parte del Post Boom, analizando sus características y su vigencia y, de manera concomitante, los movimientos anejos o posteriores a dicho movimiento, como el ...

Zinc Leaching from Tire Crumb Rubber

Science.gov (United States)

Rhodes, E. P.; Ren, J.; Mays, D. C.

2010-12-01

Recent estimates indicate that more than 2 billion scrap tires are currently stockpiled in the United States and approximately 280 million more tires are added annually. Various engineering applications utilize recycled tires in the form of shredded tire crumb rubber. However, the use of tire crumb rubber may have negative environmental impacts, especially when the rubber comes into contact with water. A review of the literature indicates that leaching of zinc from tire crumb rubber is the most significant water quality concern associated with using this material. Zinc is generally used in tire manufacturing, representing approximately 1.3% of the final product by mass. This study will report results from the U.S. Environmental Protection Agency’s (EPA’s) Synthetic Precipitation Leaching Procedure, batch leaching tests, and column leaching tests performed to quantify the process by which zinc leaches from tire crumb rubber into water. Results are interpreted with a first-order kinetic attachment/detachment model, implemented with the U.S. Agricultural Research Service software HYDRUS-1D, in order to determine the circumstances when zinc leaching from tire crumb rubber would be expected to comply with the applicable discharge limits. One potential application for recycled tires is replacing sand with tire crumb rubber in granular media filters used for stormwater pollution control. For this to be a viable application, the total zinc in the stormwater discharge must be below the EPA’s benchmark value of 0.117 mg/L.

Measuring and explaining the baby boom in the developed world in the mid-twentieth century

Directory of Open Access Journals (Sweden)

Jesús J. Sánchez-Barricarte

2018-03-01

Full Text Available Background: The early research on the baby boom tried to account for it as a logical recovery following the end of the Second World War (WWII. But it cannot be understood merely as a post-war phenomenon because its origins go back to the 1930s and early 1940s. Objective: I shall describe the methodology used to measure the total and marital baby boom and provide a detailed description of it. I shall attempt to explain the possible reasons that led to the sharp increase in the marital fertility rates and its subsequent decline. Methods: I will use various fertility indices that track the historical development of fertility (total and marital; period and cohort. Results: I show that there are major differences in the measurement of the baby boom depending on the index used. I found that the baby boom is highly heterogeneous in the 25 countries that form part of my study. It represented the logical response that families made to one period of prolonged political, economic, and military crisis (the crash of 1929 and WWII. Conclusions: Researchers who use only the total fertility indices are really analysing only the nuptiality boom, which took place during those years, rather than changes in reproductive behaviour. Contribution: I measure total and marital baby boom for 25 developed countries and perform the calculations to measure the impact of marital fertility and nuptiality on the total baby boom (TBB. I present a new explanation of the origins of the baby boom.

Design methodology for a community response questionnaire on sonic boom exposure

Science.gov (United States)

Farbry, John E., Jr.; Fields, James M.; Molino, John A.; Demiranda, Gwendolyn A.

1991-01-01

A preliminary draft questionnaire concerning community response to sonic booms was developed. Interviews were conducted in two communities that had experienced supersonic overflights of the SR-71 airplane for several years. Even though the overflights had ceased about 6 months prior to the interviews, people clearly remembered hearing sonic booms. A total of 22 people living in central Utah and 23 people living along Idaho/Washington state border took part in these interviews. The draft questionnaire was constantly modified during the study in order to evaluate different versions. Questions were developed which related to annoyance, startle, sleep disturbance, building vibration, and building damage. Based on the data collected, a proposed community response survey response instrument was developed for application in a full-scale sonic boom study.

Numerical Predictions of Sonic Boom Signatures for a Straight Line Segmented Leading Edge Model

Science.gov (United States)

Elmiligui, Alaa A.; Wilcox, Floyd J.; Cliff, Susan; Thomas, Scott

2012-01-01

A sonic boom wind tunnel test was conducted on a straight-line segmented leading edge (SLSLE) model in the NASA Langley 4- by 4- Foot Unitary Plan Wind Tunnel (UPWT). The purpose of the test was to determine whether accurate sonic boom measurements could be obtained while continuously moving the SLSLE model past a conical pressure probe. Sonic boom signatures were also obtained using the conventional move-pause data acquisition method for comparison. The continuous data acquisition approach allows for accurate signatures approximately 15 times faster than a move-pause technique. These successful results provide an incentive for future testing with greatly increased efficiency using the continuous model translation technique with the single probe to measure sonic boom signatures. Two widely used NASA codes, USM3D (Navier-Stokes) and CART3D-AERO (Euler, adjoint-based adaptive mesh), were used to compute off-body sonic boom pressure signatures of the SLSLE model at several different altitudes below the model at Mach 2.0. The computed pressure signatures compared well with wind tunnel data. The effect of the different altitude for signature extraction was evaluated by extrapolating the near field signatures to the ground and comparing pressure signatures and sonic boom loudness levels.

27 CFR 21.125 - Rubber hydrocarbon solvent.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Rubber hydrocarbon solvent. 21.125 Section 21.125 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....125 Rubber hydrocarbon solvent. (a) Rubber hydrocarbon solvent is a petroleum derivative. (b...

A Flight Research Overview of WSPR, a Pilot Project for Sonic Boom Community Response

Science.gov (United States)

Cliatt, Larry James; Haering, Ed; Jones, Thomas P.; Waggoner, Erin R.; Flattery, Ashley K.; Wiley, Scott L.

2014-01-01

In support of NASAs ongoing effort to bring supersonic commercial travel to the public, NASA Dryden Flight Research Center and NASA Langley Research Center, in cooperation with other industry organizations, conducted a flight research experiment to identify the methods, tools, and best practices for a large-scale quiet (or low) sonic boom community human response test. The name of the effort was Waveforms and Sonic boom Perception and Response. Such tests will go towards building a dataset that governing agencies like the Federal Aviation Administration and International Civil Aviation Organization will use to establish regulations for acceptable sound levels of overland sonic booms. Until WSPR, there had never been an effort that studied the response of people in their own homes and performing daily activities to non-traditional, low sonic booms.WSPR was a NASA collaborative effort with several industry partners, in response to a NASA Aeronautics Research Mission Directorate Research Opportunities in Aeronautics. The primary contractor was Wyle. Other partners included Gulfstream Aerospace Corporation, Pennsylvania State University, Tetra Tech, and Fidell Associates, Inc.A major objective of the effort included exposing a community with the sonic boom magnitudes and occurrences expected in high-air traffic regions with a network of supersonic commercial aircraft in place. Low-level sonic booms designed to simulate those produced by the next generation of commercial supersonic aircraft were generated over a small residential community. The sonic boom footprint was recorded with an autonomous wireless microphone array that spanned the entire community. Human response data was collected using multiple survey methods. The research focused on essential elements of community response testing including subject recruitment, survey methods, instrumentation systems, flight planning and operations, and data analysis methods.This paper focuses on NASAs role in the efforts

Migrant labor supply in a booming non-renewable resource economy: Cure and transmission mechanism for de-industrialization?

Science.gov (United States)

Nulle, Grant Mark

This paper challenges the determinism that booming resource economies suffer from de-industrialization, the "Dutch Disease". For several decades, economists have attempted to explain how a sudden surge in mineral and energy extraction affects an economy's output and employment from an aggregate and sectoral perspective. Economic theory shows that a "boom" in mineral and energy production is welfare enhancing to the economy experiencing it. However, the phenomenon also induces inter-sectoral adjustments among non-renewable resource (NRR), traditional traded, and non-traded industries that tend to crowd out traditional export sectors such as agriculture and manufacturing. In turn, this paper asks two fundamental questions: 1) Can the inter-sectoral adjustments wrought by a boom in NRR production be mitigated in the resource-abundant economy experiencing it; 2) Can the inter-sectoral adjustments be exported to a neighboring non-resource economy by movements in migrant labor supply? The theoretical model and empirical estimation approach presented in this paper introduces an endogenous migrant labor supply response to booms in NRR output to test the extent traditional tradable sectors shrink in the NRR-abundant economy during the boom and if such effects are exported to a neighboring jurisdiction. Using data at the U.S. county level, the empirical results show that booming economies experience positive and statistically significant rates of real income and traded sector job growth during the boom, attributable to the influx of migrant labor. By contrast, little evidence is found that non-booming counties adjacent to the booming counties experience declines in income or job growth because of labor supply outflows. Instead, the results suggest the larger the number of potential "donor" counties that can supply labor to the booming economies, the more likely the transmission of booming economy effects, namely evidence of de-industrialization, is diffused across all of the

Economic booms and risky sexual behavior: evidence from Zambian copper mining cities.

Science.gov (United States)

Wilson, Nicholas

2012-12-01

Existing studies suggest that individual and household level economic shocks affect the demand for and supply of risky sex. However, little evidence exists on the effects of an aggregate shock on equilibrium risky sexual behavior. This paper examines the effects of the early twenty-first century copper boom on risky sexual behavior in Zambian copper mining cities. The results suggest that the copper boom substantially reduced rates of transactional sex and multiple partnerships in copper mining cities. These effects were partly concentrated among young adults and copper boom induced in-migration to mining cities appears to have contributed to these reductions. Copyright © 2012. Published by Elsevier B.V.

1995 NASA High-Speed Research Program Sonic Boom Workshop. Volume 2; Configuration Design, Analysis, and Testing

Science.gov (United States)

Baize, Daniel G. (Editor)

1999-01-01

The High-Speed Research Program and NASA Langley Research Center sponsored the NASA High-Speed Research Program Sonic Boom Workshop on September 12-13, 1995. The workshop was designed to bring together NASAs scientists and engineers and their counterparts in industry, other Government agencies, and academia working together in the sonic boom element of NASAs High-Speed Research Program. Specific objectives of this workshop were to: (1) report the progress and status of research in sonic boom propagation, acceptability, and design; (2) promote and disseminate this technology within the appropriate technical communities; (3) help promote synergy among the scientists working in the Program; and (4) identify technology pacing, the development C, of viable reduced-boom High-Speed Civil Transport concepts. The Workshop was organized in four sessions: Sessions 1 Sonic Boom Propagation (Theoretical); Session 2 Sonic Boom Propagation (Experimental); Session 3 Acceptability Studies-Human and Animal; and Session 4 - Configuration Design, Analysis, and Testing.

Influence of Chair Vibrations on Indoor Sonic Boom Annoyance

Science.gov (United States)

Rathsam, Jonathan; Klos, Jacob; Loubeau, Alexandra

2015-01-01

One goal of NASA’s Commercial Supersonic Technology Project is to identify candidate noise metrics suitable for regulating quiet sonic boom aircraft. A suitable metric must consider the short duration and pronounced low frequency content of sonic booms. For indoor listeners, rattle and creaking sounds and floor and chair vibrations may also be important. The current study examined the effect of such vibrations on the annoyance of test subjects seated indoors. The study involved two chairs exposed to nearly identical acoustic levels: one placed directly on the floor, and the other isolated from floor vibrations by pneumatic elastomeric mounts. All subjects experienced both chairs, sitting in one chair for the first half of the experiment and the other chair for the remaining half. Each half of the experiment consisted of 80 impulsive noises played at the exterior of the sonic boom simulator. When all annoyance ratings were analyzed together there appeared to be no difference in mean annoyance with isolation condition. When the apparent effect of transfer bias was removed, a subtle but measurable effect of vibration on annoyance was identified.

Application of gamma irradiation for incorporation of rubber powder in the formulations EPDM and NBR rubber

International Nuclear Information System (INIS)

Kiyan, Ludmila de Ysasa Pozzo

2014-01-01

The natural decomposition of rubber is a very slow process due to its three-dimensional network formed by vulcanized crosslinked structures becoming extremely difficult to reprocess this material. The present work aims to study the application of gamma irradiation as devulcanization process for material reuse/recycling. The interactions of elastomers with ionizing radiation of a gamma source were investigated and the changes in physicochemical properties of the materials were evaluated. Formulations of NBR (acrylonitrile - butadiene) and EPDM (ethylene - propylene - diene terpolymer) from the rubber industry were crosslinked by conventional sulfur-based mixing. Master - batch was processed with rubber powder (industrial waste) and virgin rubber. The raw material (master batch) was irradiated in 60 Co source at doses of 50, 100, 150 kGy and dose rate of 5 kGy h -1 at room temperature. The irradiated material was incorporated in classical sulfur-based formulations. The formulations were characterized by: infrared spectroscopy (FTIR), thermal analysis (TG and DTG), tensile strength, elongation at break, hardness, abrasion resistance, rheometry and swelling. The results showed a predominance of chain scission at a dose of 50 kGy for EPDM rubber. For nitrile predominance of chain scission was observed at a dose of 100 kGy. These results show the possibility of the use of gamma radiation for the reuse/recycling of EPDM and nitrile rubbers. (author)

Recycling of rubber tires in electric arc furnace steelmaking: simultaneous combustion of metallurgical coke and rubber tyres blends

Energy Technology Data Exchange (ETDEWEB)

Magdalena Zaharia; Veena Sahajwalla; Byong-Chul Kim; Rita Khanna; N. Saha-Chaudhury; Paul O' Kane; Jonathan Dicker; Catherine Skidmore; David Knights [University of New South Wales, Sydney, NSW (Australia). School of Materials Science and Engineering

2009-05-15

The present study investigates the effect of addition of waste rubber tires on the combustion behavior of its blends with coke for carbon injection in electric arc furnace steelmaking. Waste rubber tires were mixed in different proportions with metallurgical coke (MC) (10:90, 20:80, 30:70) for combustion and pyrolysis at 1473 K in a drop tube furnace (DTF) and thermogravimetric analyzer (TGA), respectively. Under experimental conditions most of the rubber blends indicated higher combustion efficiencies compared to those of the constituent coke. In the early stage of combustion the weight loss rate of the blends is much faster compared to that of the raw coke due to the higher volatile yield of rubber. The presence of rubber in the blends may have had an impact upon the structure during the release and combustion of their high volatile matter (VM) and hence increased char burnout. Measurements of micropore surface area and bulk density of the chars collected after combustion support the higher combustion efficiency of the blends in comparison to coke alone. The surface morphology of the 30% rubber blend revealed pores in the residual char that might be attributed to volatile evolution during high temperature reaction in oxygen atmosphere. Physical properties and VM appear to have a major effect upon the measured combustion efficiency of rubber blends. The study demonstrates that waste rubber tires can be successfully co-injected with metallurgical coke in electric arc furnace steelmaking process to provide additional energy from combustion. 44 refs., 11 figs., 2 tabs.

Natural rubber/nitrile butadiene rubber/hindered phenol composites with high-damping properties

Directory of Open Access Journals (Sweden)

Xiuying Zhao

2015-10-01

Full Text Available New natural rubber (NR/nitrile butadiene rubber (NBR/hindered phenol (AO-80 composites with high-damping properties were prepared in this study. The morphological, structural, and mechanical properties were characterized by atomic force microscopy (AFM, polarized Fourier transform infrared spectrometer (FTIR, dynamic mechanical thermal analyzer (DMTA, and a tensile tester. Each composite consisted of two phases: the NR phase and the NBR/AO-80 phase. There was partial compatibility between the NR phase and the NBR/AO-80 phase, and the NR/NBR/AO-80 (50/50/20 composite exhibited a co-continuous morphology. Strain-induced crystallization occurred in the NR phase at strains higher than 200%, and strain-induced orientation appeared in the NBR/AO-80 phase with the increase of strain from 100% to 500%. The composites had a special stress–strain behavior and mechanical properties because of the simultaneous strain-induced orientation and strain-induced crystallization. In the working temperature range of a seismic isolation bearing, the composites (especially the NR/NBR/AO-80 (50/50/20 composite presented a high loss factor, high area of loss peak (TA, and high hysteresis energy. Therefore, the NR/NBR/AO-80 rubber composites are expected to have important application as a high-performance damping material for rubber bearing.

Lignocellulosic fiber reinforced rubber composites

CSIR Research Space (South Africa)

Jacob John, Maya

2009-04-01

Full Text Available Natural Rubber (NR) is a naturally occurring elastomeric polymer of isoprene (2-methyl-1,3-butadiene). It can be extracted from latex of only one kind of tree, the Hevea braziliensis. Hevea rubber is produced in many tropical regions of Southeast...

76 FR 20532 - Safety Zone; Boom Days, Niagara River, Niagara Falls, NY

Science.gov (United States)

2011-04-13

...-AA00 Safety Zone; Boom Days, Niagara River, Niagara Falls, NY AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on the Niagara River... Marina and a portion of the Niagara River, Niagara Falls, NY during the Boom Days Fireworks on April 16...

A study on creep properties of laminated rubber bearings. Pt. 1. Creep properties and numerical simulations of thick rubber bearings

International Nuclear Information System (INIS)

Matsuda, Akihiro; Yabana, Shuichi

2000-01-01

In this report, to evaluate creep properties and effects of creep deformation on mechanical properties of thick rubber bearings for three-dimensional isolation system, we show results of compression creep test for rubber bearings of various rubber materials and shapes and development of numerical simulation method. Creep properties of thick rubber bearings were obtained from compression creep tests. The creep strain shows steady creep that have logarithmic relationships between strain and time and accelerated creep that have linear relationships. We make numerical model of a rubber material with nonlinear viscoelastic constitutional equations. Mechanical properties after creep loading test are simulated with enough accuracy. (author)

Treatment of wastewater from rubber industry in Malaysia ...

African Journals Online (AJOL)

Treatment of wastewater from rubber industry in Malaysia. ... Discharge of untreated rubber effluent to waterways resulted in water pollution that affected the human health. ... Key words: Rubber industry, effluent, waste management, Malaysia.

Presence of Polycyclic Aromatic Hydrocarbons in Rubber Packaging Materials and in Parenteral Formulations Stored in Bottles With Rubber Stoppers.

Science.gov (United States)

Bohrer, Denise; Viana, Carine; Barichello, Marcia M; de Moura, Juliane F; de Carvalho, Leandro M; Nascimento, Paulo C

2017-08-01

Rubber closures are the primary packaging material for sterile preparations intended for repeated use. Important features of rubber closures are achieved after additives are added to the elastomeric material that compounds the rubber. Among these additives is carbon black. Because of its origin, carbon black may contain polycyclic aromatic hydrocarbons (PAHs). The U.S. Environmental Protection Agency has identified 16 priority PAHs on the basis of concerns that they cause or might cause cancer in animals and humans. Regulatory agencies impose carbon black purity specifications based on limits for total PAHs (0.5 mg/kg) and benzo[a]pyrene (5 μg/kg) or benzo[a]pyrene only (250 μg/kg). PAHs in rubber packaging used for pharmaceutical formulations and in parenteral products stored in containers with rubber stoppers were investigated. To this end, the method proposed by the National Institute for Occupational Safety and Health-based on high-performance liquid chromatography with ultraviolet and fluorescence detection-was adapted to determine the levels of PAHs in rubber stoppers (gray and red) and in lipid emulsions and amino acid solutions stored in bottles with rubber stoppers. The rubber materials were shown to contain 12 PAHs, in concentrations ranging from 0.25-3.31 µg/g. Only 1 of 18 samples (11 amino acid solutions and 7 lipid emulsions) was uncontaminated. The most prevalent contaminants were pyrene, benzo[a]pyrene, and fluoranthene. The total PAH concentrations in the samples ranged from 0.11-5.96 µg/mL. Components of parenteral nutrition may be contaminated with PAHs, and rubber stoppers represent a potential source of these contaminants.

Rubber friction: role of the flash temperature

International Nuclear Information System (INIS)

Persson, B N J

2006-01-01

When a rubber block is sliding on a hard rough substrate, the substrate asperities will exert time-dependent deformations of the rubber surface resulting in viscoelastic energy dissipation in the rubber, which gives a contribution to the sliding friction. Most surfaces of solids have roughness on many different length scales, and when calculating the friction force it is necessary to include the viscoelastic deformations on all length scales. The energy dissipation will result in local heating of the rubber. Since the viscoelastic properties of rubber-like materials are extremely strongly temperature dependent, it is necessary to include the local temperature increase in the analysis. At very low sliding velocity the temperature increase is negligible because of heat diffusion, but already for velocities of order 10 -2 m s -1 the local heating may be very important. Here I study the influence of the local heating on the rubber friction, and I show that in a typical case the temperature increase results in a decrease in rubber friction with increasing sliding velocity for v>0.01 m s -1 . This may result in stick-slip instabilities, and is of crucial importance in many practical applications, e.g. for tyre-road friction and in particular for ABS braking systems

Simulation and controller design for an agricultural sprayer boom leveling system

KAUST Repository

Sun, Jian

2011-01-01

According to the agricultural precision requirements, the distance from sprayer nozzles to the corps should be kept between 50 cm to 70 cm. The sprayer boom also needs to be kept parallel to the field during the operation process. Thus we can guarantee the quality of the chemical droplets distribution on the crops. In this paper we introduced a sprayer boom leveling system for agricultural sprayer vehicles with electro-hydraulic auto-leveling system. The suitable hydraulic actuating cylinder and valve were selected according to the specific systemic specifications. Furthermore, a compensation controller for the electro-hydraulic system was designed based on the mathematical model. With simulations we can optimize the performance of this controller to make sure a fast leveling response to the inclined sprayer boom. © 2011 IEEE.

Design, Construction, and Evaluation of Rubber Friction Tester

Directory of Open Access Journals (Sweden)

Mehdi Razzaghi Kashani

2012-12-01

Full Text Available Coeffcient of  friction  (COF  for  rubber parts  is one of  the key parameters in their interaction with solid rough surfaces (micrometer to millimeter scales,  such  as  tire-road  interactions. COF  of  rubber  depends  on  viscoelastic properties of rubber, roughness characteristics of the counter-part surface, and process variables such as contact nominal pressure and sliding speed. Due to the need for measuring COF  for  rubber,  a  new  friction  tester, with  continuous  variation  of nominal pressure and sliding speed, was designed and constructed in order to assess the effect of above mentioned parameters. Tire tread compounds, as the most common rubber part  in  the feld of  rubber  tribology, was used  for  this purpose. Viscoelastic properties of compounds were varied by changing composition of styrene-butadiene rubber (SBR and butadiene rubber (BR in the blend. Effect of surface roughness was evaluated by using silicon-carbide papers with different roughness parameters. By statistical analysis it was shown that the designed friction tester has high accuracy in measuring the coeffcient of friction of rubber and differentiating the effective parameters. Increasing the nominal pressure led to reduction of COF and increase in sliding speed forced it through a maximum. In conclusion, the loss factor of the compound and asymmetry in roughness distribution of the counter-surface are considered as the most effective parameters on COF of rubber.

Babies Bottom Out--A 'Maybe Boom'

Science.gov (United States)

Science News, 1977

1977-01-01

Data for the period September 1976 through April 1977 indicate a rise in the United States birth rate; however, the rate is still below the replacement level. It is speculated that the increase is an "echo" effect to the post-World War II baby boom which peaked in 1957. (SL)

Cryogenic Deflashing for Rubber Products

Directory of Open Access Journals (Sweden)

Abhilash M.

2018-01-01

Full Text Available Deflashing is the process of removal of excess flashes from the rubber products. Initially deflashing was a manual operation where dozen of workers, seated at small work stations would take each part and trim the excess rubber off with scissors, knives or by grinding. Still the same method is employed in most of the rubber industry. The drawbacks of this method are demand inconsistent and repeatable quality. Work done by hand is often inconsistent. There are commercially available cryogenic deflashing machine but they are too expensive hence cost effectiveness is also a prime factor. The objective of this paper is to develop a technique, to identify the media through which the flashes can be removed easily and effectively. Based on the test results obtained from testing of five different types of media, ABCUT Steel media gave best results. The testing of the ABCUT Steel media on rubber samples like O-rings, grommet tail door, bottom bush etc. shows good results.

Characterization of crumb rubber modified by gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Faldini, Sonia B.; Terence, Mauro C.; Miranda, Leila F.; Munhoz, Antonio H.; Domingues, Leandro S.; Coghetto, Gregory, E-mail: sfaldini@yahoo.com.br, E-mail: mauroterence@yahoo.com.br [Universidade Presbiteriana Mackenzie (UPM), Sao Paulo, SP (Brazil). Escola de Engenharia. Engenharia de Materiais

2013-07-01

The use of crumb rubber from scrap tires has become a common practice in the construction of roads, leading to improved properties of the asphalt and decreasing the environmental pollution. In this study, crumb rubber was modified by gamma radiation to eventually incorporate it into the asphalt and verify potential improvements of their properties. The crumb rubber modified by gamma radiation in the dose 500 kGy and 1000kGy was characterized by thermal analysis, infrared spectroscopy and scanning electron microscopy. The dose of radiation used has no effect on degradation temperatures. It is observed that the IV spectra of untreated rubbers and rubbers irradiated have substantially the same profile. The results indicate that despite small morphological changes in the irradiated rubber, they do not influence its degradation temperature and composition. (author)

Characterization of crumb rubber modified by gamma radiation

International Nuclear Information System (INIS)

Faldini, Sonia B.; Terence, Mauro C.; Miranda, Leila F.; Munhoz, Antonio H.; Domingues, Leandro S.; Coghetto, Gregory

2013-01-01

The use of crumb rubber from scrap tires has become a common practice in the construction of roads, leading to improved properties of the asphalt and decreasing the environmental pollution. In this study, crumb rubber was modified by gamma radiation to eventually incorporate it into the asphalt and verify potential improvements of their properties. The crumb rubber modified by gamma radiation in the dose 500 kGy and 1000kGy was characterized by thermal analysis, infrared spectroscopy and scanning electron microscopy. The dose of radiation used has no effect on degradation temperatures. It is observed that the IV spectra of untreated rubbers and rubbers irradiated have substantially the same profile. The results indicate that despite small morphological changes in the irradiated rubber, they do not influence its degradation temperature and composition. (author)

Silane grafted natural rubber and its compatibilization effect on silica-reinforced rubber tire compounds

NARCIS (Netherlands)

Sengloyluan, K.; Sahakaro, K.; Dierkes, W. K.; Noordermeer, J. W.M.

2017-01-01

Natural Rubber (NR) grafted with 3-octanoylthio-1-propyltriethoxysilane (NXT) was prepared by melt mixing using 1,1′-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane as initiator at 140 °C with NXT contents of 10 and 20 parts per hundred rubber [phr] and initiator 0.1 phr. The silane grafted on NR

Alternative sources of natural rubber

NARCIS (Netherlands)

Mooibroek, H.; Cornish, K.

2000-01-01

Rubber (cis-1,4-polyisoprene) is one of the most important polymers naturally produced by plants because it is a strategic raw material used in more than 40,000 products, including more than 400 medical devices. The sole commercial source, at present, is natural rubber harvested from the Brazilian

A Flight Research Overview of WSPR, a Pilot Project for Sonic Boom Community Response

Science.gov (United States)

Cliatt, Larry J., II; Haering, Edward A., Jr.; Jones, Thomas P.; Waggoner, Erin R.; Flattery, Ashley K.; Wiley, Scott L.

2014-01-01

In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, the NASA Armstrong Flight Research Center and the NASA Langley Research Center, in cooperation with other industry organizations, conducted a flight research experiment to identify the methods, tools, and best practices for a large-scale quiet (or low) sonic boom community human response test. The name of the effort was Waveforms and Sonic boom Perception and Response (WSPR). Such tests will be applied to building a dataset that governing agencies such as the Federal Aviation Administration and the International Civil Aviation Organization will use to establish regulations for acceptable sound levels of overland sonic booms. The WSPR test was the first such effort that studied responses to non-traditional low sonic booms while the subject persons were in their own homes and performing daily activities.The WSPR test was a NASA collaborative effort with several industry partners, in response to a NASA Aeronautics Research Mission Directorate Research Opportunities in Aeronautics. The primary contractor was Wyle (El Segundo, California). Other partners included Gulfstream Aerospace Corporation (Savannah, Georgia); Pennsylvania State University (University Park, Pennsylvania); Tetra Tech, Inc. (Pasadena, California); and Fidell Associates, Inc. (Woodland Hills, California).A major objective of the effort included exposing a community to the sonic boom magnitudes and occurrences that would be expected to occur in high-air traffic regions having a network of supersonic commercial aircraft in place. Low-level sonic booms designed to simulate those produced by the next generation of commercial supersonic aircraft were generated over a small residential community. The sonic boom footprint was recorded with an autonomous wireless microphone array that spanned the entire community. Human response data were collected using multiple

Butyl Rubber: Compound Development and Characterization

National Research Council Canada - National Science Library

Sloan, James

2000-01-01

...), to develop the standard butyl rubber compound. The strategy of this work was to compound- and compression-mold high-quality, uniform butyl rubber experimental sheets and to evaluate their cure properties, mechanical properties...

Geotechnical Properties of Rubber Tires and Sediments Mixtures

Directory of Open Access Journals (Sweden)

H. Sellaf

2014-04-01

Full Text Available An experimental work was undertaken to study the effect of rubber tires on the geotechnical properties of a dredged sediment, using a mixing ratio of large size. For comparison, two types of soil were studied (dredged sediment from Fergoug dam and Tizi Tuff from the north west of Algeria. Taking into account the high compressibility and the low water absorption of the rubber tires, grain size analysis, density, Atterberg limits analysis, chemical composition, direct shear tests, loading-unloading tests, modified Proctor and CBR tests are performed on the two soils and their mixtures with different scrap tire rubber (10, 20, 25 and 50%. The results show that liquid limits and plastic indexes decrease with the scrap tire rubber content and that the decrease is more significant for soil with high plasticity. Cohesion also decreases with scrap tire rubber content when the internal friction angle is vacillating. Compression and recompression indexes increase gradually with the scrap tire rubber content and the variation for compression index is more significant for the two soils. Compaction characteristics and CBR values decrease with scrap tire rubber content. The CBR values for W=3% are important compared to those with W=5% excepted for mixture with (75% tuff and 25% scrap tire rubber. The results show that the scrap tire rubber can be used as a reinforcement material for dredged soil, but with a content that should not highly affect the compressibility.

Crack Velocities in Natural Rubber.

Science.gov (United States)

1982-05-01

vulcanized natural rubber (3). The surprisingly low value for natural rubber was attributed to highly anisotropic elastic behavior at high strains...Dr. R.L. Rabie Hercules Incorporated WX-2, MS-952 Alleghany Ballistic Lab Los Alamos National Lab. P.O. Box 210 P.O. Box 1663 Washington, D.C. 21502

Reconstrucción estética de la frente en carcinoma basocelular

Directory of Open Access Journals (Sweden)

J. De Abullarade

2014-06-01

Full Text Available La frente es una de las áreas más difíciles de reconstruir debido a su propia anatomía, la piel es firme, gruesa, y escasamente elástica. Esto ha supuesto un reto para muchos, y a algunos nos ha llevado a tratar de innovar en la reconstrucción de esta zona anatómica. En este artículo, clasificamos imaginariamente las áreas reconstructivas de la frente de acuerdo a las estructuras vecinas y describimos un tipo de reconstrucción para cada zona en la que movilizamos colgajos rectangulares, siguiendo las líneas naturales de la frente.

Practical application of thermoreversibly Cross-linked rubber products

Science.gov (United States)

Polgar, L. M.; Picchioni, F.; de Ruiter, E.; van Duin, M.

2017-07-01

Currently, rubber products cannot simply be reprocessed after their product life, due to the irreversible cross-linking methods traditionally applied. The purpose of this work is to investigate how thermoreversible cross-linking of rubbers via Diels Alder chemistry can be used for the development of recyclable rubber products. Unfortunately, the applicability of the thermoreversible EPM-g-furan/BM system appears to be limited to room temperature applications, because of the rapid deterioration of the compression set at elevated temperatures compared to irreversibly cross-linked EPM. However, the use of EPM rubber modified with thiophene or cyclopentadiene moieties may extend the temperature application range and results in rubber products with acceptable properties. Finally, rubber products generally comprise fillers such as silica, carbon black or fibers. In this context, the reinforcing effect of short cut aramid fibers on the material properties of the newly developed thermoreversibly cross-linked EPM rubbers was also studied. The material properties of the resulting products were found to be comparable to those of a fiber reinforced, peroxide cured reference sample.

Biodiesel production methods of rubber seed oil: a review

Science.gov (United States)

Ulfah, M.; Mulyazmi; Burmawi; Praputri, E.; Sundari, E.; Firdaus

2018-03-01

The utilization of rubber seed as raw material of biodiesel production is seen highly potential in Indonesia. The availability of rubber seeds in Indonesia is estimated about 5 million tons per annum, which can yield rubber seed oil about 2 million tons per year. Due to the demand of edible oils as a food source is tremendous and the edible oil feedstock costs are far expensive to be used as fuel, production of biodiesel from non-edible oils such as rubber seed is an effective way to overcome all the associated problems with edible oils. Various methods for producing biodiesel from rubber seed oil have been reported. This paper introduces an optimum condition of biodiesel production methods from rubber seed oil. This article was written to be a reference in the selection of methods and the further development of biodiesel production from rubber seed oil. Biodiesel production methods for rubber seed oils has been developed by means of homogeneous catalysts, heterogeneous catalysts, supercritical method, ultrasound, in-situ and enzymatic processes. Production of biodiesel from rubber seed oil using clinker loaded sodium methoxide as catalyst is very interesting to be studied and developed further.

Synergistic effect of plasma-modified halloysite nanotubes and carbon black in natural rubber-butadiene rubber blend

NARCIS (Netherlands)

Poikelispaa, Minna; Das, Amit; Dierkes, Wilma K.; Vuorinen, Jyrki

2013-01-01

Halloysite nanotubes (HNTs) were investigated concerning their suitability for rubber reinforcement. As they have geometrical similarity with carbon nanotubes, they were expected to impart a significant reinforcement effect on the rubber compounds but the dispersion of the nanofillers is difficult.

Butterfly valve of all rubber lining type

International Nuclear Information System (INIS)

Shimada, Shosaku; Nakatsuma, Sumiya; Sasaki, Iwao; Aoki, Naoshi.

1982-01-01

The valves used for the circulating water pipes for condensers in nuclear and thermal power stations have become large with the increase of power output, and their specifications have become strict. The materials for the valves change from cast iron to steel plate construction. To cope with sea water corrosion, rubber lining has been applied to the internal surfaces of valve boxes, and the build-up welding of stainless steel has been made on the edges of valves. However, recently it is desired to develop butterfly valves, of which the whole valve disks are lined with hard rubber. For the purpose of confirming the performance of large bore valves, a 2600 mm bore butterfly valve of all rubber lining type was used, and the opening and closing test of 1100 times was carried out by applying thermal cycle and pressure difference and using artifical sea water. Also the bending test of hard rubber lining was performed with test pieces. Thus, it was confirmed that the butterfly valves of all rubber lining type have the performance exceeding that of the valves with build-up welding. The course of development of the valves of all rubber lining type, the construction and the items of confirmation by tests of these valves, and the tests of the valve and the hard rubber lining described above are reported. (Kako, I.)

RoxB Is a Novel Type of Rubber Oxygenase That Combines Properties of Rubber Oxygenase RoxA and Latex Clearing Protein (Lcp).

Science.gov (United States)

Birke, Jakob; Röther, Wolf; Jendrossek, Dieter

2017-07-15

Only two types of rubber oxygenases, rubber oxygenase (RoxA) and latex clearing protein (Lcp), have been described so far. RoxA proteins (RoxAs) are c -type cytochromes of ≈70 kDa produced by Gram-negative rubber-degrading bacteria, and they cleave polyisoprene into 12-oxo-4,8-dimethyltrideca-4,8-diene-1-al (ODTD), a C 15 oligo-isoprenoid, as the major end product. Lcps are common among Gram-positive rubber degraders and do not share amino acid sequence similarities with RoxAs. Furthermore, Lcps have much smaller molecular masses (≈40 kDa), are b -type cytochromes, and cleave polyisoprene to a mixture of C 20 , C 25 , C 30 , and higher oligo-isoprenoids as end products. In this article, we purified a new type of rubber oxygenase, RoxB Xsp (RoxB of Xanthomonas sp. strain 35Y). RoxB Xsp is distantly related to RoxAs and resembles RoxAs with respect to molecular mass (70.3 kDa for mature protein) and cofactor content (2 c -type hemes). However, RoxB Xsp differs from all currently known RoxAs in having a distinctive product spectrum of C 20 , C 25 , C 30 , and higher oligo-isoprenoids that has been observed only for Lcps so far. Purified RoxB Xsp revealed the highest specific activity of 4.5 U/mg (at 23°C) of all currently known rubber oxygenases and exerts a synergistic effect on the efficiency of polyisoprene cleavage by RoxA Xsp RoxB homologs were identified in several other Gram-negative rubber-degrading species, pointing to a prominent function of RoxB for the biodegradation of rubber in Gram-negative bacteria. IMPORTANCE The enzymatic cleavage of rubber (polyisoprene) is of high environmental importance given that enormous amounts of rubber waste materials are permanently released (e.g., by abrasion of tires). Research from the last decade has discovered rubber oxygenase A, RoxA, and latex clearing protein (Lcp) as being responsible for the primary enzymatic attack on the hydrophobic and water-insoluble biopolymer poly( cis -1,4-isoprene) in Gram

Greenhouse Gas Emissions from Rubber Industry in Thailand

NARCIS (Netherlands)

Jawjit, W.; Kroeze, C.; Rattanapan, S.

2010-01-01

Rubber production has been taking place in Thailand for many decades. Thailand is currently the world's largest natural rubber producer. We present emissions of greenhouse gases associated with the production of fresh latex, and three primary rubber products, including concentrated latex, block

Development of rubber material for high radiation field

International Nuclear Information System (INIS)

Nakatsukasa, Sadayoshi; Tabasaki, Takeshi; Yoshida, Akihiro; Kadowaki, Yoshito

2013-01-01

Generally flexible polymeric materials exposed to radiation can't be used because they soften or harden remarkably in high radiation environment. Aromatic polymers such as PEEK, PI, and PES are also known as radiation-proof polymeric materials. Aromatic polymers are very hard, they can't be used for products like a packing where flexibility is required. We developed a new vulcanized rubber compound by the use of various additives and polymer blend. This developed rubber compound has a high radiation-proof performance by reaction balance of cross-linking and decomposition in this rubber. This rubber compound has a rubber elasticity even if exposed to radiation of MGy level, and its radiation proof is more than 5 times as high as conventional polymeric materials. This rubber compound is much more flexible than the aromatic polymers which are the used as conventional radiation-proof polymers. (author)

Thermal endurance tests on silicone rubber specimens

International Nuclear Information System (INIS)

Warburton, C.

1977-07-01

Thermal endurance tests have been performed on a range of silicone rubber specimens at temperature above 300 0 C. It is suggested that the rubber mix A2426, the compound from which Wylfa sealing rings are manufactured, will fail at temperatures above 300 0 C within weeks. Hardness measurements show that this particular rubber performs in a similar manner to Walker's S.I.L./60. (author)

Crumb Rubber Recycling in Enhancing Damping Properties of Concrete

Science.gov (United States)

Sugapriya, P.; Ramkrishnan, R.

2018-02-01

Damping plays a major role in the design of roadside structures that gets affected due to vibrations transmitted from moving traffic. In this study, fine aggregates were partially replaced with crumb rubber in concrete, at varying percentages of 5, 10, 15 and 20% by weight. Three different sets of concrete, mixed with crumb rubber were prepared using raw rubber, treated rubber and treated rubber with partial replacement of cement. Cement was partially replaced with Ultra-Fine Ground Granulated Blast furnace Slag (UFGGBS) for this study. Samples were cast, cured and tested for various properties on the 7th and 28th day. The damping ratio and frequency of the peak value from a number of waves in rubber incorporated beams were found out using a FFT Analyser along with its Strength, Damping and Sorptivity characteristics. SEM analysis was conducted to analyse the micro structural bonding between rubber and concrete. The mode shapes of pavement slabs were modelled and analysed using a FEM tool, ANSYS. From the results, the behaviour of the three sets of rubberized concrete were compared and analysed, and an optimum percentage for crumb rubber and UFGGBS was proposed to achieve best possible damping without compromising the strength properties.

Cream concentrated latex for foam rubber products

Science.gov (United States)

Suksup, R.; Imkaew, C.; Smitthipong, W.

2017-12-01

Fresh natural latex (around 40% rubber and 60% water) can be transformed to concentrated natural latex (around 60% rubber and 40% water) in order to realise economical transportation and easier latex product’s preparation. The concentrated natural latex is an extremely valuable material. It can be applied for many types of products, for example, foam rubber as pillow and mattress, elastic band, etc. Industrially, the concentrated natural latex can be prepared by centrifugation which requires an enormous expensive machine. From the eco-friendly products point of view, most of rubber entrepreneurs in the world try to develop a green rubber product. So, the main objective of this study is to prepare the cream concentrated latex without any sophisticated machine. Thus, we work on a simple, cheap and green method that does not use any expensive machine but uses water-based chemical as sodium alginate to prepare the cream concentrated latex. The optimal amount of sodium alginate in the latex was studied. The main characteristics of the cream concentrated latex were tested by various technics, such as alkalinity, total solid content (TSC), dry rubber content (DRC), etc. We found that there are no significant differences of results between fresh natural latex and cream concentrated latex, except for the TSC and DRC. The TSC and DRC of cream latex are higher than those of fresh natural latex. Finally, we propose a model of natural rubber particle and sodium alginate to form the cream concentrated latex.

Spill-Overs of a Resource Boom: Evidence from Zambian Copper Mines

OpenAIRE

Alexander Lippert

2014-01-01

Do local populations benefit from resource booms? How strong are market linkages between the mining sector and the regional economy? This paper exploits exogenous variation in mine-level production volumes generated by the recent copper boom in Zambia to shed light on these questions. Using a novel dataset, I find robust evidence that an increase in local copper production improves living standards in the surroundings of the mines even for households not directy employed in the mining sector:...

Compatibilization efficiency of carboxylated nitrile rubber and epoxy pre-polymer in nitrile/acrylic rubber blends

Directory of Open Access Journals (Sweden)

Micheli L. Celestin

2013-01-01

Full Text Available An investigation has been made of the effects from a compatibilizer, viz. carboxylated nitrile rubber (XNBR, on several properties of nitrile rubber (NBR and acrylic rubber (ACM blends, including curing characteristics, mechanical, dynamic mechanical and dielectric properties. The presence of XNBR until 10 phr resulted in an improvement of the ultimate tensile properties, especially elongation at break. The mechanical properties associated to the volume fraction of rubber in the network (Vr and torque values suggest the co-vulcanization phenomenon imparted by the compatibilization. The oil resistance of NBR/ACM (50:50 wt. (% blends (compatibilized and non compatibilized was similar to that observed for pure ACM and significantly higher than NBR. The addition of small amounts of epoxy pre-polymer in combination with XNBR resulted in an additional improvement of the tensile properties. The dynamic mechanical and dielectric properties of the blends were also investigated. The loss modulus values of the compatibilized blends were significantly lower indicating an increase of the elastic characteristics. All blends presented two dielectric relaxation peaks confirming the heterogeneity of the compatibilized blends

Proceedings of the Rubber Association of Canada's 7. biennial 2006 rubber recycling symposium : changing concepts

International Nuclear Information System (INIS)

2006-01-01

Rising energy costs and concerns over the environment have contributed to a renewed focus on recycling for many governments and industries. This conference examined recent trends affecting rubber recycling activities as well as the legislative environment and its impacts on future recycling activities. Major rubber recycling markets were reviewed, and emerging product ideas were evaluated. Industry stewardship model and governance models were discussed. The impacts of new advances in tire technology and manufacturing on the rubber recycling industry were also investigated. Issues concerning fixed tipping fees and incentive structures were discussed, and effective management strategies for the recycling of large off-the-road tires were evaluated. Tire-derived fuel (TDF) is the largest market in North America for scrap tires, and TDF may continue to grow as a result of rising fossil fuel costs. Issues and challenges related to the introduction of TDF to new communities were discussed. New developments in tire derived aggregates (TDA) and ground rubber were also reviewed. Twenty-eight presentations were given at this conference, 3 of which were catalogued separately for inclusion in this database. refs., tabs., figs

Evapotranspiration of rubber ( Hevea brasiliensis ) cultivated at two plantation sites in Southeast Asia: RUBBER EVAPOTRANSPIRATION IN SE ASIA

Energy Technology Data Exchange (ETDEWEB)

Giambelluca, Thomas W. [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya Japan; Mudd, Ryan G. [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Liu, Wen [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Ziegler, Alan D. [Department of Geography, National University of Singapore, Singapore Singapore; Kobayashi, Nakako [Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya Japan; Kumagai, Tomo' omi [Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya Japan; Miyazawa, Yoshiyuki [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Research Institute of East Asia Environments, Kyushu University, Fukuoka Japan; Lim, Tiva Khan [Cambodian Rubber Research Institute, Phnom Penh Cambodia; Huang, Maoyi [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Fox, Jefferson [East-West Center, Honolulu Hawai' i USA; Yin, Song [Cambodian Rubber Research Institute, Phnom Penh Cambodia; Mak, Sophea Veasna [Cambodian Rubber Research Institute, Phnom Penh Cambodia; Kasemsap, Poonpipope [Department of Horticulture, Kasetsart University, Bangkok Thailand

2016-02-01

The expansion of rubber (Hevea brasiliensis) cultivation to higher latitudes and higher elevations in southeast Asia is part of a dramatic shift in the direction of rural land cover change in the region toward more tree covered landscapes. To investigate the possible effects of increasing rubber cultivation in the region on ecosystem services including water cycling, eddy covariance towers were established to measure ecosystem fluxes within two rubber plantations, one each in Bueng Kan, northeastern Thailand, and Kampong Cham, central Cambodia. The results show that evapotranspiration (ET) at both sites is strongly related to variations in available energy and leaf area, and moderately controlled by soil moisture. Measured mean annual ET was 1128 and 1272 mm for the Thailand and Cambodia sites, respectively. After adjustment for energy closure, mean annual was estimated to be 1211 and 1459 mm yr at the Thailand and Cambodia sites, respectively. Based on these estimates and that of another site in Xishuangbanna, southwestern China, it appears that of rubber is higher than that of other tree dominated land covers in the region, including forest. While measurements by others in non rubber tropical ecosystems indicate that at high net radiation sites is at most only slightly higher than for sites with lower net radiation, mean annual rubber increases strongl with increasing net radiation across the three available rubber plantation observation sites. With the continued expansion of tree dominated land covers, including rubber cultivation, in southeast Asia, the possible association between commercially viable, fast growing tree crop species Giambelluca et al. Evapotranspiration of rubber (Havea brasiliensis) cultivated at two sites in southeast Asia and their relatively high water use raises concerns about potential effects on water and food security.

Nylon-6/rubber blends: 6. Notched tensile impact testing of nylon-6(ethylene-propylene rubber) blends

NARCIS (Netherlands)

Dijkstra, Krijn; Dijkstra, K.; ter Laak, J.A.; ter Laak, J.; Gaymans, R.J.

1994-01-01

The deformation and fracture behaviour of nylon-6/EPR (ethylene-propylene rubber) blends is studied as a function of strain rate and rubber content. Therefore, tensile experiments are conducted on notched specimens over a broad range of draw speeds (including strain rates as encountered in normal

Stimuli-responsive cement-reinforced rubber.

Science.gov (United States)

Musso, Simone; Robisson, Agathe; Maheshwar, Sudeep; Ulm, Franz-Josef

2014-05-14

In this work, we report the successful development of a cement-rubber reactive composite with reversible mechanical properties. Initially, the composite behaves like rubber containing inert filler, but when exposed to water, it increases in volume and reaches a stiffness that is intermediate between that of hydrogenated nitrile butadiene rubber (HNBR) and hydrated cement, while maintaining a relatively large ductility characteristic of rubber. After drying, the modulus increases even further up to 400 MPa. Wet/drying cycles prove that the elastic modulus can reversibly change between 150 and 400 MPa. Utilizing attenuated total reflection Fourier transform infrared spectroscopy), we demonstrate that the high pH produced by the hydration of cement triggers the hydrolysis of the rubber nitrile groups into carboxylate anions. Thus, the salt bridges, generated between the carboxylate anions of the elastomer and the cations of the filler, are responsible for the reversible variations in volume and elastic modulus of the composite as a consequence of environmental moisture exposure. These results reveal that cement nanoparticles can successfully be used to accomplish a twofold task: (a) achieve an original postpolymerization modification that allows one to work with carboxylate HNBR (HXNBR) not obtained by direct copolymerization of carboxylate monomers with butadiene, and (b) synthesize a stimuli-responsive polymeric composite. This new type of material, having an ideal behavior for sealing application, could be used as an alternative to cement for oil field zonal isolation applications.

Microbial detoxification of waste rubber material by wood-rotting fungi.

Science.gov (United States)

Bredberg, Katarina; Andersson, B Erik; Landfors, Eva; Holst, Olle

2002-07-01

The extensive use of rubber products, mainly tires, and the difficulties to recycle those products, has resulted in world wide environmental problems. Microbial devulcanisation is a promising way to increase the recycling of rubber materials. One obstacle is that several microorganisms tested for devulcanisation are sensitive to rubber additives. A way to overcome this might be to detoxify the rubber material with fungi prior to the devulcanisation. In this study, 15 species of white-rot and brown-rot fungi have been screened with regard to their capacity to degrade an aromatic model compound in the presence of ground waste tire rubber. The most effective fungus, Resinicium bicolor, was used for detoxification of rubber material. Increase in growth of the desulfurising bacterium Thiobacillus ferrooxidans in presence of the rubber treated with Resinicium bicolor compared to untreated rubber demonstrated that detoxification with fungi is possible.

Natural rubber producing plants: An overview

African Journals Online (AJOL)

User

2013-03-20

Mar 20, 2013 ... Currently, Hevea brasiliensis has been only one resource for commercial natural rubber production. ...... ADVANTAGES AND DISADVANTAGES ... polymer chain. Combinations of an amine antioxidant and a zinc dialkyldithiocarbamate have been used to counter these effects, improving guayule rubber ...

Design of Self-Healing Supramolecular Rubbers by Introducing Ionic Cross-Links into Natural Rubber via a Controlled Vulcanization.

Science.gov (United States)

Xu, Chuanhui; Cao, Liming; Lin, Baofeng; Liang, Xingquan; Chen, Yukun

2016-07-13

Introducing ionic associations is one of the most effective approaches to realize a self-healing behavior for rubbers. However, most of commercial rubbers are nonpolar rubbers without now available functional groups to be converted into ionic groups. In this paper, our strategy was based on a controlled peroxide-induced vulcanization to generate massive ionic cross-links via polymerization of zinc dimethacrylate (ZDMA) in natural rubber (NR) and exploited it as a potential self-healable material. We controlled vulcanization process to retard the formation of covalent cross-link network, and successfully generated a reversible supramolecular network mainly constructed by ionic cross-links. Without the restriction of covalent cross-linkings, the NR chains in ionic supramolecular network had good flexibility and mobility. The nature that the ionic cross-links was easily reconstructed and rearranged facilitating the self-healing behavior, thereby enabling a fully cut sample to rejoin and retain to its original properties after a suitable self-healing process at ambient temperature. This study thus demonstrates a feasible approach to impart an ionic association induced self-healing function to commercial rubbers without ionic functional groups.

[Total analysis of organic rubber additives].

Science.gov (United States)

He, Wen-Xuan; Robert, Shanks; You, Ye-Ming

2010-03-01

In the present paper, after middle pressure chromatograph separation using both positive phase and reversed-phase conditions, the organic additives in ethylene-propylene rubber were identified by infrared spectrometer. At the same time, by using solid phase extraction column to maintain the main component-fuel oil in organic additves to avoid its interfering with minor compounds, other organic additves were separated and analysed by GC/Ms. In addition, the remaining active compound such as benzoyl peroxide was identified by CC/Ms, through analyzing acetone extract directly. Using the above mentioned techniques, soften agents (fuel oil, plant oil and phthalte), curing agent (benzoylperoxide), vulcanizing accelerators (2-mercaptobenzothiazole, ethyl thiuram and butyl thiuram), and antiagers (2, 6-Di-tert-butyl-4-methyl phenol and styrenated phenol) in ethylene-propylene rubber were identified. Although the technique was established in ethylene-propylene rubber system, it can be used in other rubber system.

Vibration characteristics of a deployable controllable-geometry truss boom

Science.gov (United States)

Dorsey, J. T.

1983-01-01

An analytical study was made to evaluate changes in the fundamental frequency of a two dimensional cantilevered truss boom at various stages of deployment. The truss could be axially deployed or retracted and undergo a variety of controlled geometry changes by shortening or lengthening the telescoping diagonal members in each bay. Both untapered and tapered versions of the truss boom were modeled and analyzed by using the finite element method. Large reductions in fundamental frequency occurred for both the untapered and tapered trusses when they were uniformly retracted or maneuvered laterally from their fully deployed position. These frequency reductions can be minimized, however, if truss geometries are selected which maintain cantilever root stiffness during truss maneuvers.

Investigation of surface halide modification of nitrile butadiene rubber

Science.gov (United States)

Sukhareva, K. V.; Mikhailov, I. A.; Andriasyan, Yu O.; Mastalygina, E. E.; Popov, A. A.

2017-12-01

The investigation is devoted to the novel technology of surface halide modification of rubber samples based on nitrile butadiene rubber (NBR). 1,1,2-trifluoro-1,2,2-trichlorethane was used as halide modifier. The developed technology is characterized by production stages reduction to one by means of treating the rubber compound with a halide modifier. The surface halide modification of compounds based on nitrile butadiene rubber (NBR) was determined to result in increase of resistance to thermal oxidation and aggressive media. The conducted research revealed the influence of modification time on chemical resistance and physical-mechanical properties of rubbers under investigation.

Improving rubber concrete by waste organic sulfur compounds.

Science.gov (United States)

Chou, Liang-Hisng; Lin, Chun-Nan; Lu, Chun-Ku; Lee, Cheng-Haw; Lee, Maw-Tien

2010-01-01

In this study, the use of crumb tyres as additives to concrete was investigated. For some time, researchers have been studying the physical properties of concrete to determine why the inclusion of rubber particles causes the concrete to degrade. Several methods have been developed to improve the bonding between rubber particles and cement hydration products (C-S-H) with the hope of creating a product with an improvement in mechanical strength. In this study, the crumb tyres were treated with waste organic sulfur compounds from a petroleum refining factory in order to modify their surface properties. Organic sulfur compounds with amphiphilic properties can enhance the hydrophilic properties of the rubber and increase the intermolecular interaction forces between rubber and C-S-H. In the present study, a colloid probe of C-S-H was prepared to measure these intermolecular interaction forces by utilizing an atomic force microscope. Experimental results showed that rubber particles treated with waste organic sulfur compounds became more hydrophilic. In addition, the intermolecular interaction forces increased with the adsorption of waste organic sulfur compounds on the surface of the rubber particles. The compressive, tensile and flexural strengths of concrete samples that included rubber particles treated with organic sulfur compound also increased significantly.

Circuit racing, track texture, temperature and rubber friction

Science.gov (United States)

Sharp, R. S.; Gruber, P.; Fina, E.

2016-04-01

Some general observations relating to tyre shear forces and road surfaces are followed by more specific considerations from circuit racing. The discussion then focuses on the mechanics of rubber friction. The classical experiments of Grosch are outlined and the interpretations that can be put on them are discussed. The interpretations involve rubber viscoelasticity, so that the vibration properties of rubber need to be considered. Adhesion and deformation mechanisms for energy dissipation at the interface between rubber and road and in the rubber itself are highlighted. The enquiry is concentrated on energy loss by deformation or hysteresis subsequently. Persson's deformation theory is outlined and the material properties necessary to apply the theory to Grosch's experiments are discussed. Predictions of the friction coefficient relating to one particular rubber compound and a rough surface are made using the theory and these are compared with the appropriate results from Grosch. Predictions from Persson's theory of the influence of nominal contact pressure on the friction coefficient are also examined. The extent of the agreement between theory and experiment is discussed. It is concluded that there is value in the theory but that it is far from complete. There is considerable scope for further research on the mechanics of rubber friction.

Determination of the Mechanical Properties of Rubber by FT-NIR

OpenAIRE

Pornprasit, Rattapol; Pornprasit, Philaiwan; Boonma, Pruet; Natwichai, Juggapong

2016-01-01

Mechanical tests, for example, tensile and hardness tests, are usually used to evaluate the properties of rubber materials. In this work, mechanical properties of selected rubber materials, that is, natural rubber (NR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), and ethylene propylene diene monomer (EPDM), were evaluated using a near infrared (NIR) spectroscopy technique. Here, NR/NBR and NR/EPDM blends were first prepared. All of the samples were then scanned using a FT-...

Ultraviolet curing of acrylated liquid natural rubber for surface coating application

OpenAIRE

Kannikar Kwanming; Pairote Klinpituksa; Wae-asae Waehamad

2009-01-01

Ultraviolet curable acrylated liquid natural rubber was prepared by grafting of photosensitive molecule onto liquid natural rubber for surface coating application. The liquid natural rubber (LNR) was firstly obtained by degradation of natural rubber latex with hydrogen peroxide and cobalt acetylacetonate at 65oC for 72 hrs. The preparation of acrylated natural rubber was carried out by the reaction of acrylic acid and epoxidized liquid natural rubber (ELNR) prior obtained from LNR with formic...

ATLAS IV in situ heating test in Boom Clay

International Nuclear Information System (INIS)

Chen, Guangjing; Li, Xiangling; Verstricht, Jan; Sillen, Xavier

2012-01-01

Document available in extended abstract form only. The small scale in-situ ATLAS (Admissible Thermal Loading for Argillaceous Storage) tests are performed to assess the hydro-mechanical effects of a thermal transient on the host Boom clay at the HADES underground research facility in Mol, Belgium. The initial test set-up, consisting of a heater borehole and two observation boreholes, was installed in 1991-1992. The first test (later named 'ATLAS I') was then performed from July 1993 to June 1996; during this time, the heater dissipated a constant power of 900 W. During the second phase ('ATLAS II'), the heating power was doubled (1800 W) and maintained constant from June 1996 to May 1997. This was followed by shutdown and natural cooling starting from June 1997 on. To broaden the THM characterization of the Boom clay at a larger scale and at different temperature levels, the test set-up was extended in 2006 by drilling two additional instrumented boreholes (AT97E and AT98E). The heater was switched on again from April 2007 to April 2008 with a stepwise power increase, followed by an instantaneous shutdown. This phase is called 'ATLAS III'. The above tests have provided a large set of good quality and well documented data on temperature, pore water pressure and total stress; these data allowed to make several interesting observations regarding the thermal anisotropy and THM coupling in the Boom clay. The straightforward geometry and well defined boundary conditions of the tests facilitate the comparison between measurement and numerical modeling studies. Based on the three dimensional coupled THM modeling of the ATLAS III test, the good agreement between measurement and numerical modeling of temperature and pore water pressure yields a set of THM parameters and confirms the thermo-mechanical anisotropy of the Boom clay. To get a better insight in the anisotropic THM behavior of the Boom clay, a new upward instrumented borehole was drilled above the ATLAS heater at

Some Tribological Characterization of “EPDM” Rubber

Directory of Open Access Journals (Sweden)

A. Mukhopadhyay

2014-06-01

Full Text Available Ethylene Propylene Diene Monomer (EPDM rubber emerges as a dominant elastomer for major engineering applications. The major properties of EPDM are its outstanding heat, ozone and weather resistance ability. It has a good resistance to polar substances and steam condition too. In automobiles EPDM rubber has a common use as seals. This includes door seals, window seals, trunk seals and sometimes hood seals. Frequently these seals are the source of noise due to the movement of the door versus the car body. This is due to friction between the EPDM rubber parts and the mating surfaces. Thus, the contact iteration between the rubber sealing and the indenting object must be known to optimize the performance of rubber sealing. However, it is need less to mention that the behaviour of any viscoelastic material is very difficult to be predicted. In the present work various tribo-characteristics of EPDM rubber of different hardness have been evaluated utilizing the available laboratory test facilities in the Jadavpur University, Kolkata, India. Compression tests have been carried out using ‘Instron’ to determine the flow behaviour of EPDM rubber of different hardness both in dry as well as under different conditions of lubrication. The flow behaviour like load -vs.- elongation curves, true stress -vs.- elongation curves and true stress -vs.- true strain curves have been drawn from the experimental data. Abrasive wear behaviour has been evaluated using a two-body abrasion tester and the pattern abrasion has been appraised through SEM/EDAX study. Experimental results reveal that the hardness of EPDM rubber has significant effect on the flow behaviour and wear characteristics. The hardness, again, depends on the proportion of carbon black (CB content. Thus it can be stated that the flow behaviour can be governed by controlling the CB concentration in the EPDM rubber. Based on the experimental results conclusion has been drawn accordingly. Some of the

Elastic Deployable Composite Tubular Roll-Out Boom, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Deployable Space Systems (DSS) has developed an affordable and ultra-lightweight elastically self-deployable Roll-Out Boom technology that provides affordability and...

Energy usage in the rubber industry

Energy Technology Data Exchange (ETDEWEB)

Soederstroem, M.

1980-01-01

The rubber industry has several energy-intensive steps, such as mastication of natural rubber, mixing and extrusion, and vulcanization. Opportunities for energy savings would be available with a continuous mixing process, heat recovery from cooling waters, and abandonment of thermal conduction in vulcanization. 6 figures. (DCK)

Reinforcing effect of plasma modified halloysite nanotubes in a carbon black filled natural rubber-butadien rubber matrix

NARCIS (Netherlands)

Poikelispaa, Minna; Das, Amit; Dierkes, Wilma K.; Vuorinen, Jyrki

2011-01-01

Rubber composites are generally produced by the direct incorporation of fillers like carbon black and/or silica into the rubber matrix. The incorporation of different types of nanofillers is the subject of recent research with the aim of preparing composites with special compositions and properties.

The enzymatic synthesis of rubber polymer in Parthenium argentatum Gray

International Nuclear Information System (INIS)

Benedict, C.R.; Madhavan, S.; Greenblatt, G.A.; Venkatachalam, K.V.; Foster, M.A.

1990-01-01

Washed rubber particles isolated from stem homogenates of Parthenium argentatum Gray by ultracentrifugation and gel filtration on columns of LKB Ultrogel AcA34 contain rubber transferase which catalyzes the polymerization of isopentenyl pyrophosphate into rubber polymer. The polymerization reaction requires Mg 2+ isopentenyl pyrophosphate, and an allylic pyrophosphate. The K m values for Mg 2+ , isopentenyl pyrophosphate, and dimethylallyl pyrophosphate were 5.2 x 10 -4 molar, 8.3 x 10 -5 molar, and 9.6 x 10 -5 molar, respectively. The molecular characteristics of the rubber polymer synthesized from [ 14 C]isopentenyl pyrophosphate were examined by gel permeation chromatography. The peak molecular weight of the radioactive polymer increased from 70,000 in 15 minutes to 750,000 in 3 hours. The weight average molecular weight of the polymer synthesized over a 3 hour period was 1.17 x 10 6 compared to 1.49 x 10 6 for the natural rubber polymer extracted from the rubber particles. Over 90% of the in vitro formation of the rubber polymer was de novo from dimethylallyl pyrophosphate and isopentenyl pyrophosphate. Treatment of the washed rubber particles with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate solubilized the rubber transferase. The solubilized enzyme(s) catalyzed the polymerization of isopentenyl pyrophosphate into rubber polymer with a peak molecular weight of 1 x 10 5 after 3 hours of incubation with Mg 2+ and dimethylallyl pyrophosphate. The data support the conclusion that the soluble preparation of rubber transferase is capable of catalyzing the formation of a high molecular weight rubber polymer from an allylic pyrophosphate initiator and isopentenyl pyrophosphate monomer

Fabrication of shape memory natural rubber using palmitic acid

Directory of Open Access Journals (Sweden)

Jeff Sze-Hua Wee

2017-10-01

Full Text Available This paper investigates the practicability of fabricating a shape memory natural rubber with the use of palmitic acid as the swelling agent. Strips of natural rubber samples were swollen in molten palmitic acid at 75 °C. Equilibrium swelling of natural rubber with palmitic acid was found to occur at approximately 50 min of swelling time. Under cooling effect, the palmitic acid crystallized to form a percolated crystalline platelet network. These networks allow fabricated shape memory natural rubber (SMNR to deform and recover its shape at a temperature above the melting point of palmitic acid. Under controlled uniaxial stress, the natural rubber sample with 0 parts per hundred rubber (phr carbon black loading exhibits fixity and recovery of 80 ± 10%. Motivation of this research is primarily on practicability of palmitic acid to be used as a swelling agent for shape memory properties. Results show that palmitic acid is a relatively good swelling agent to induce shape memory properties into natural rubber.

Fabrication of Wood-Rubber Composites Using Rubber Compound as a Bonding Agent Instead of Adhesives

Directory of Open Access Journals (Sweden)

Dongwei Shao

2016-06-01

Full Text Available Differing from the hot-pressing method in the manufacturing of traditional wood-rubber composites (WRCs, this study was aimed at fabricating WRCs using rubber processing to improve water resistance and mechanical properties. Three steps were used to make WRCs, namely, fiber-rubber mixing, tabletting, and the vulcanization molding process. Ninety-six WRC panels were made with wood fiber contents of 0%–50% at rotor rotational speeds of 15–45 rpm and filled coefficients of 0.55–0.75. Four regression equations, i.e., the tensile strength (Ts, elongation at break (Eb, hardness (Ha and rebound resilience (Rr as functions of fiber contents, rotational speed and filled coefficient, were derived and a nonlinear programming model were developed to obtain the optimum composite properties. Although the Ts, Eb and Rr of the panels were reduced, Ha was considerably increased by 17%–58% because of the wood fiber addition. Scanning electron microscope images indicated that fibers were well embedded in rubber matrix. The 24 h water absorption was only 1%–3%, which was much lower than commercial wood-based composites.

Fabrication of Wood-Rubber Composites Using Rubber Compound as a Bonding Agent Instead of Adhesives.

Science.gov (United States)

Shao, Dongwei; Xu, Min; Cai, Liping; Shi, Sheldon Q

2016-06-14

Differing from the hot-pressing method in the manufacturing of traditional wood-rubber composites (WRCs), this study was aimed at fabricating WRCs using rubber processing to improve water resistance and mechanical properties. Three steps were used to make WRCs, namely, fiber-rubber mixing, tabletting, and the vulcanization molding process. Ninety-six WRC panels were made with wood fiber contents of 0%-50% at rotor rotational speeds of 15-45 rpm and filled coefficients of 0.55-0.75. Four regression equations, i.e. , the tensile strength ( T s), elongation at break ( E b), hardness ( H a) and rebound resilience ( R r) as functions of fiber contents, rotational speed and filled coefficient, were derived and a nonlinear programming model were developed to obtain the optimum composite properties. Although the T s, E b and R r of the panels were reduced, H a was considerably increased by 17%-58% because of the wood fiber addition. Scanning electron microscope images indicated that fibers were well embedded in rubber matrix. The 24 h water absorption was only 1%-3%, which was much lower than commercial wood-based composites.

Seismic isolation rubber bearings for nuclear facilities

International Nuclear Information System (INIS)

Fujita, Takafumi

1991-01-01

This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial-stress-shear-strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of FBR plants. It also discusses the protection method against aging and the quality control which are important for implementation. (orig./HP)

Seismic isolation rubber bearings for nuclear facilities

International Nuclear Information System (INIS)

Fujita, Takafumi

1989-01-01

This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial stress-shear strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of fast breeder reactor (FBR) plants. The paper also discusses the protection method against aging and the quality control which are important for implementation

Review of food toxicological issues associated in rubber products

OpenAIRE

Ng, Mei Xiang; Ong, S.P.; Hii, C.L.; Chuah, L.A.; Law, C.L.

2014-01-01

Over the centuries, rubber latex gained its popularity in machinery application due to its unique thermal properties, high elasticity and excellent impact resistance. It is widely accepted in food industry as rubber has good resistance to chemicals, including acids, alkalis and salts. For instance, rubber components comprise of couplings, shields, dust covers, gaskets and seals exist as group or standalone component in food manufacturing equipments or machinery. Even though most of the rubber...

Rubber friction and tire dynamics

International Nuclear Information System (INIS)

Persson, B N J

2011-01-01

We propose a simple rubber friction law, which can be used, for example, in models of tire (and vehicle) dynamics. The friction law is tested by comparing numerical results to the full rubber friction theory (Persson 2006 J. Phys.: Condens. Matter 18 7789). Good agreement is found between the two theories. We describe a two-dimensional (2D) tire model which combines the rubber friction model with a simple mass-spring description of the tire body. The tire model is very flexible and can be used to accurately calculate μ-slip curves (and the self-aligning torque) for braking and cornering or combined motion (e.g. braking during cornering). We present numerical results which illustrate the theory. Simulations of anti-blocking system (ABS) braking are performed using two simple control algorithms.

Rubber friction and tire dynamics.

Science.gov (United States)

Persson, B N J

2011-01-12

We propose a simple rubber friction law, which can be used, for example, in models of tire (and vehicle) dynamics. The friction law is tested by comparing numerical results to the full rubber friction theory (Persson 2006 J. Phys.: Condens. Matter 18 7789). Good agreement is found between the two theories. We describe a two-dimensional (2D) tire model which combines the rubber friction model with a simple mass-spring description of the tire body. The tire model is very flexible and can be used to accurately calculate μ-slip curves (and the self-aligning torque) for braking and cornering or combined motion (e.g. braking during cornering). We present numerical results which illustrate the theory. Simulations of anti-blocking system (ABS) braking are performed using two simple control algorithms.

The marriage boom and marriage bust in the United States: An age-period-cohort analysis.

Science.gov (United States)

Schellekens, Jona

2017-03-01

In the 1950s and 1960s there was an unprecedented marriage boom in the United States. This was followed in the 1970s by a marriage bust. Some argue that both phenomena are cohort effects, while others argue that they are period effects. The study reported here tested the major period and cohort theories of the marriage boom and bust, by estimating an age-period-cohort model of first marriage for the years 1925-79 using census microdata. The results of the analysis indicate that the marriage boom was mostly a period effect, although there were also cohort influences. More specifically, the hypothesis that the marriage boom was mostly a response to rising wages is shown to be consistent with the data. However, much of the marriage bust can be accounted for by unidentified cohort influences, at least until 1980.

Forecasting Natural Rubber Price In Malaysia Using Arima

Science.gov (United States)

Zahari, Fatin Z.; Khalid, Kamil; Roslan, Rozaini; Sufahani, Suliadi; Mohamad, Mahathir; Saifullah Rusiman, Mohd; Ali, Maselan

2018-04-01

This paper contains introduction, materials and methods, results and discussions, conclusions and references. Based on the title mentioned, high volatility of the price of natural rubber nowadays will give the significant risk to the producers, traders, consumers, and others parties involved in the production of natural rubber. To help them in making decisions, forecasting is needed to predict the price of natural rubber. The main objective of the research is to forecast the upcoming price of natural rubber by using the reliable statistical method. The data are gathered from Malaysia Rubber Board which the data are from January 2000 until December 2015. In this research, average monthly price of Standard Malaysia Rubber 20 (SMR20) will be forecast by using Box-Jenkins approach. Time series plot is used to determine the pattern of the data. The data have trend pattern which indicates the data is non-stationary data and the data need to be transformed. By using the Box-Jenkins method, the best fit model for the time series data is ARIMA (1, 1, 0) which this model satisfy all the criteria needed. Hence, ARIMA (1, 1, 0) is the best fitted model and the model will be used to forecast the average monthly price of Standard Malaysia Rubber 20 (SMR20) for twelve months ahead.

Fatigue life of automotive rubber jounce bumper

International Nuclear Information System (INIS)

Sidhu, R S; Ali, Aidy

2010-01-01

It is evident that most rubber components in the automotive industry are subjected to repetitive loading. Vigorous research is needed towards improving the safety and reliability of the components. The study was done on an automotive rubber jounce bumper with a rubber hardness of 60 IRHD. The test was conducted in displacement-controlled environment under compressive load. The existing models by Kim, Harbour, Woo and Li were adopted to predict the fatigue life. The experimental results show strong similarities with the predicted models.

30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

Science.gov (United States)

2010-07-01

...-voltage lines. 77.807-2 Section 77.807-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-2 Booms and masts; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of any...

Determination of the Mechanical Properties of Rubber by FT-NIR

Directory of Open Access Journals (Sweden)

Rattapol Pornprasit

2016-01-01

Full Text Available Mechanical tests, for example, tensile and hardness tests, are usually used to evaluate the properties of rubber materials. In this work, mechanical properties of selected rubber materials, that is, natural rubber (NR, styrene butadiene rubber (SBR, nitrile butadiene rubber (NBR, and ethylene propylene diene monomer (EPDM, were evaluated using a near infrared (NIR spectroscopy technique. Here, NR/NBR and NR/EPDM blends were first prepared. All of the samples were then scanned using a FT-NIR spectrometer and fitted with an integration sphere working in a diffused reflectance mode. The spectra were correlated with hardness and tensile properties. Partial least square (PLS calibration models were built from the spectra datasets with preprocessing techniques, that is, smoothing and second derivative. This indicated that reasonably accurate models, that is, with a coefficient of determination [R2] of the validation greater than 0.9, could be achieved for the hardness and tensile properties of rubber materials. This study demonstrated that FT-NIR analysis can be applied to determine hardness and tensile values in rubbers and rubber blends effectively.

Characterization of groundwater flow in the environment of the Boom Clay (Campine, Belgium)

International Nuclear Information System (INIS)

Gedeon, M.; Labat, S.; Wemaere, I.; Wouters, L.

2010-01-01

Document available in extended abstract form only. In Belgium, the Boom Clay formation is considered as reference host rock for the geological disposal of radioactive waste. Aquifers surrounding the Boom Clay play a passive role in the context of the disposal safety whereby the radionuclides are diluted by groundwater flow. The groundwater flow in these aquifers has been studied since decades. This research involves observations of groundwater levels in the regional and local piezo-metric networks, several site investigations including geophysics and core-drilled boreholes and groundwater modelling. In this context, groundwater modelling represents the integration of the site characterization efforts and provides a comprehensive tool for constraining the models used in the safety assessment of the geological disposal. Since 1985, groundwater levels are observed monthly in the regional piezo-metric network. It consists of 142 filters monitoring the groundwater levels at 45 sites. Along with the observed groundwater levels from the local piezo-metric network (concentrated around the Mol-Dessel site for surface disposal), these data provide an excellent insight into the evolution of the groundwater levels. Moreover, they represent a calibration (validation) dataset for groundwater flow modelling. The groundwater system forming the environment of the Boom Clay host rock was characterized during several site investigation campaigns, within which seven core-drilled boreholes were realized, whereby hydraulic parameters and hydro-stratigraphy of the groundwater system could be collected. The dataset obtained from the above mentioned campaigns was complemented by archived data on hydraulic testing in the aquifers in order to build a comprehensive groundwater model integrating these data into a single numerical representation of the groundwater system. Three regional groundwater models have been developed integrating the site characterization data collected in the north

Application of gamma irradiation for incorporation of rubber powder in the formulations of acrylonitrile-butadiene rubber (NBR)

International Nuclear Information System (INIS)

Kiyan, Ludmila Y.P.; Parra, Duclerc Fernandes

2013-01-01

Full text: Polymeric materials do not decompose easily, disposal of waste polymers is a major environmental problem of global character. Recycling is an economical alternative and environmentally recommended for polymers consumed and discarded by society. As regards the rubber in object, its natural decomposition is much slower due to their highly crosslinked, in three-dimensional networks, structures which makes it an infusible and insoluble material. Moreover, these three dimensional structures entails several problems for their recovery and reprocessing. The aim of this paper was to study the behavior of NBR rubber recycle. It was used rubber powder from industry. The powder was irradiated in master-batch composition and used directly in classical formulations for rubber vulcanization. The master-batch processed was irradiated at doses of 50, 100 and 150kGy in 60 Co source at 5 kGy s -1 rate, at room temperature. Gamma radiation created active sites during devulcanization that promoted further integration of the rubber powder in formulations for commercial use. The processes were compared and their products were characterized by analytical methods of the physical properties such as tensile strength and elongation. The greatest change in the properties of polymeric materials by exposure to ionizing radiation resulted mainly of two main reactions occurring in the polymer molecule: chains scission (degradation) and crosslinking. Although these two processes occur simultaneously in all the polymers, the predominance of one or other effect depends mainly of the chemical structure of each polymer, and the irradiation conditions. In the results was observed the behavior of nitrile rubber under different doses and radiation improvement of the mechanical properties. (author)

Application of gamma irradiation for incorporation of rubber powder in the formulations of acrylonitrile-butadiene rubber (NBR)

Energy Technology Data Exchange (ETDEWEB)

Kiyan, Ludmila Y.P.; Parra, Duclerc Fernandes, E-mail: ludmilapozzo@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente (CQMA)

2013-07-01

Full text: Polymeric materials do not decompose easily, disposal of waste polymers is a major environmental problem of global character. Recycling is an economical alternative and environmentally recommended for polymers consumed and discarded by society. As regards the rubber in object, its natural decomposition is much slower due to their highly crosslinked, in three-dimensional networks, structures which makes it an infusible and insoluble material. Moreover, these three dimensional structures entails several problems for their recovery and reprocessing. The aim of this paper was to study the behavior of NBR rubber recycle. It was used rubber powder from industry. The powder was irradiated in master-batch composition and used directly in classical formulations for rubber vulcanization. The master-batch processed was irradiated at doses of 50, 100 and 150kGy in {sup 60}Co source at 5 kGy s{sup -1} rate, at room temperature. Gamma radiation created active sites during devulcanization that promoted further integration of the rubber powder in formulations for commercial use. The processes were compared and their products were characterized by analytical methods of the physical properties such as tensile strength and elongation. The greatest change in the properties of polymeric materials by exposure to ionizing radiation resulted mainly of two main reactions occurring in the polymer molecule: chains scission (degradation) and crosslinking. Although these two processes occur simultaneously in all the polymers, the predominance of one or other effect depends mainly of the chemical structure of each polymer, and the irradiation conditions. In the results was observed the behavior of nitrile rubber under different doses and radiation improvement of the mechanical properties. (author)

Properties of tire rubber with zinc-containing technological additives

Directory of Open Access Journals (Sweden)

S. N. Kayushnikov

2017-01-01

Full Text Available In this paper, we studied the influence of zinc-containing technological additives on partial replacement of zinc oxide and stearic acid on deformation-strength and performance properties of tire elastomeric compositions based on polyisoprene rubber and combination of oil-filled butadiene-styrene and polybutadiene rubbers. It was revealed that partial replacement of zinc oxide and stearic acid with zinc-containing technological additives does not significantly affect the basic physico-mechanical properties of rubbers based on synthetic rubbers of general use. It was determined that the introduction of zinc-containing technological additives SCC2 in combination with zinc oxide in all the studied ratios and SCC3 in combination with zinc oxide in 4: 1 and 3: 1 ratios leads to increase (up to 10.4% of the resistance of these rubbers under the action of temperature-force fields, which is probably due to a more even distribution of polar components of curing system in non-polar elastomeric matrix, as well as the type of cross-links formed during vulcanization under the action of surface-active additives. It has been found that the introduction of zinc-containing additives into the elastomeric compositions based on SRMS-30 ARKM-15 + SRD in combination with zinc oxide leads to increase to 6.3% of wear resistance of rubbers, which may be due to a lower defectiveness of vulcanization structure of these rubbers, concentration of stress centers in the material. For rubbers based on SRI-3, preservation of bond strength of rubber with a textile cord at a sufficiently high level is shown.

Development of rubberized geopolymer interlocking bricks

Directory of Open Access Journals (Sweden)

Bashar S Mohammed

2018-06-01

Full Text Available Waste tires contribute badly to the environment on a huge scale as they are bulky, non-biodegradable, and prone to fire and being a shelter for mosquitos and other insects. This paper reports on a novel approach towards the development of rubberized brick by utilizing crumb rubber as the sole fine aggregate in the production of geopolymer interlocking bricks. The response surface methodology (RSM from Design Experts software has been used to determine the numbers of trial mixes and their corresponding ingredients. A total of thirteen trial mixes were carried out and tested for compressive strength and the RSM model was developed to predict the design mix based on the targeted compressive strength. The mix design was obtained to be an 18 M for NaOH and 0.8 solution to fly ash ratio. The geopolymer interlocking rubberized bricks were then produced and tested for compressive strength, dimension, modulus of rupture, water absorption, initial rate of absorption, and efflorescence. The geopolymer interlocking rubberised bricks presented a low compressive and flexural strength and a high-water absorption capacity. The bricks were rated as non-effloresced and classified as 3rd class bricks which can be used as non-load bearing material. It is recommended to utilize nano silica in order to increase the strength of the brick. Keywords: Rubberized bricks, Crumb rubber, Interlocking bricks, Geopolymer, Response surface methodology

Correlatos valorativos de atitudes frente à tatuagem Value correlates of attitudes toward tattoo

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Valdiney V Gouveia

2010-12-01

Full Text Available Este estudo objetivou conhecer em que medida os valores explicam as atitudes frente à tatuagem e estas, por sua vez, predizem a intenção de tatuar-se. Participaram 263 estudantes universitários de João Pessoa, com idade média de 20,7 anos, a maioria homem (54,7% e solteira (91%. Estes responderam a Escala de Atitudes frente à Tatuagem, o Questionário dos Valores Básicos e perguntas demográficas (idade, sexo, religiosidade. Os resultados indicaram atitudes dos participantes mais negativas frente à tatuagem, sobretudo aqueles de ciências exatas e naturais. Comprovou-se a adequação de um modelo triádico, onde os valores predisseram as atitudes frente à tatuagem e, estas, a intenção de tatuar-se. Especificamente, a subfunção normativa promoveu atitudes negativas frente à tatuagem, enquanto a subfunção experimentação favoreceu aquelas mais positivas. Conclui-se que as atitudes frente à tatuagem têm base valorativa, explicando a intenção de tatuar-se. Sugeriram-se pesquisas futuras que contribuam para explicar as atitudes frente à tatuagem.This study investigated the extent to which values explain the attitudes towards tattoos and these, in turn, predict the intention of tattooing. Participants were 263 undergraduate students from João Pessoa (Brazil, with mean age of 20.7 years, mostly men (54.7% and unmarried (91%. They answered the Attitudes toward Tattoo Scale, the Basic Values Survey and demographic questions (age, gender, and religiosity. Results indicated that the participants' attitudes toward tattooing were predominantly negatives, especially among students of natural and exact sciences. The adequacy of a triadic model was proved, where human values predicted attitudes toward tattooing and these, the intention of getting tattooed. Specifically, the value subfunction normative promoted negative attitudes toward tattooing, while the subfunction excitement favored more positive attitudes. In conclusion, attitudes

Modification of rubber surface by UV surface grafting

International Nuclear Information System (INIS)

Shanmugharaj, A.M.; Kim, Jin Kuk; Ryu, Sung Hun

2006-01-01

Rubber surface is subjected to ultraviolet radiation (UV) in the presence of allylamine and radiation sensitizer benzophenone (BP). Fourier transform infrared spectral studies reveal the presence of allylamine on the surface. The presence of irregular needle shapes on the surface as observed in scanning electron micrographs also confirms the polymerized allylamine on the surface. Allylamine coatings have been further confirmed from atomic force microscopy (AFM) analysis. Thermogravimetric analysis (TGA) reveals that allylamine coating on the rubber surface lowers the thermal degradation rate. The contact angle between the water and rubber surface decreases for the modified rubber surface confirming the surface modification due to UV surface grafting

Life assessment of rubber articles in fuels

OpenAIRE

Selldén, Emmy

2013-01-01

The choice of rubber material for use in sealings and hoses in the fuel system is of great importance. If a wrong type of rubber is used, premature failure during service may occur. This impacts the environmental performance, the safety during driving, uptime and economy of the transport. In this diploma work, rubbers for use in sealing and hoses in the fuel system have been evaluated to assess which materials have the potential to be used under long-term use in contact with commercial fuels....

Research Progress in Graphene/Rubber Conducting Nanocomposites

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DONG Hui-min

2017-03-01

Full Text Available The conductive mechanism of graphene/rubber nanocomposites was introduced.Advances in the synthesis and properties of graphene and its derivatives, modifications of graphene, along with its hybrid fillers, as well as fabrication of related rubber conducting nanocomposites were reviewed.Many factors affecting the electrical properties, such as fabrication method, vulcanization, temperature, pressure, frequency and media etc. were also summarized.It was pointed out that the further research should be focused on multi-component graphene/rubber nanocomposites and its double percolation phenomenon.

Boron-Loaded Silicone Rubber Scintillators

Energy Technology Data Exchange (ETDEWEB)

Bell, Z.W.; Maya, L.; Brown, G.M.; Sloop, F.V.Jr

2003-05-12

Silicone rubber received attention as an alternative to polyvinyltoluene in applications in which the scintillator is exposed to high doses because of the increased resistance of the rubber to the formation of blue-absorbing color centers. Work by Bowen, et al., and Harmon, et al., demonstrated their properties under gamma/x-ray irradiation, and Bell, et al. have shown their response to thermal neutrons. This last work, however, provided an example of a silicone in which both the boron and the scintillator were contained in the rubber as solutes, a formulation which led to the precipitation of solids and sublimation of the boron component. In the present work we describe a scintillator in which the boron is chemically bonded to the siloxane and so avoids the problem of precipitation and loss of boron to sublimation. Material containing up to 18% boron, by weight, was prepared, mounted on photomultipliers, and exposed to both neutron and gamma fluxes. Pulse height spectra showing the neutron and photon response were obtained, and although the light output was found to be much poorer than from samples in which boron was dissolved, the higher boron concentrations enabled essentially 100% neutron absorption in only a few millimeters' thickness of rubber.

An evaluation of propane as a fuel for testing fire-resistant oil spill containment booms

International Nuclear Information System (INIS)

Walton, W. D.; Twilley, W. H.

1997-01-01

A series of experiments have been conducted to measure and compare the thermal exposure to a fire-resistant boom from liquid hydrocarbon fuel and propane fires. The objective was to test the potential of propane fueled fires as a fire source for testing fire-resistant oil spill containment booms.Thermal exposure from propane fires have been measured with and without waves. Results indicated that although propane diffusion flames on water look like liquid hydrocarbon fuel flames and produce very little smoke, the heat flux at the boom location from propane fires is about 60 per cent of that from liquid hydrocarbon fuel fires. Despite the attractive features in terms of ease of application, control and smoke emissions, it was concluded that the low heat flux would preclude the application of propane as a fuel for evaluating fire resistant containment booms. 2 refs., 7 figs

Asphalt concrete modified by rubber crumbs in transport construction.

Science.gov (United States)

Duhovny, G. S.; Karpenko, AV

2018-03-01

High-temperature and low-temperature characteristics of the rubber-bitumen binder and rubber asphalt concrete based on it are researched. The determination method of binder’s low-temperature characteristics is offered. The estimation of binder’s and pavement’s stability against technological and operational aging is evaluated. Estimation of environmental and economic aspects of using rubber crumbs is made. The possibility of using rubber crumbs as modifier of organic binder for production of asphalt concrete on its base is justified.

Economic Booms and Risky Sexual Behavior: Evidence from Zambian Copper Mining Cities

OpenAIRE

Nicholas Wilson

2010-01-01

Existing studies suggest that individual and household level economic shocks affect the demand for and supply of risky sex. However, little evidence exists on the effects of an aggregate shock on equilibrium risky sexual behavior. This paper examines the effects of the early twenty-first century copper boom on risky sexual behavior in Zambian copper mining cities. The results indicate that the copper boom substantially reduced rates of transactional sex and multiple partnerships in copper min...

On the response of rubbers at high strain rates.

Energy Technology Data Exchange (ETDEWEB)

Niemczura, Johnathan Greenberg (University of Texas-Austin)

2010-02-01

In this report, we examine the propagation of tensile waves of finite deformation in rubbers through experiments and analysis. Attention is focused on the propagation of one-dimensional dispersive and shock waves in strips of latex and nitrile rubber. Tensile wave propagation experiments were conducted at high strain-rates by holding one end fixed and displacing the other end at a constant velocity. A high-speed video camera was used to monitor the motion and to determine the evolution of strain and particle velocity in the rubber strips. Analysis of the response through the theory of finite waves and quantitative matching between the experimental observations and analytical predictions was used to determine an appropriate instantaneous elastic response for the rubbers. This analysis also yields the tensile shock adiabat for rubber. Dispersive waves as well as shock waves are also observed in free-retraction experiments; these are used to quantify hysteretic effects in rubber.

Biodiesel Production from Rubber Seed Oil via Esterification Process

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W Widayat

2012-07-01

Full Text Available One promise source of alternative energy is biodiesel from rubber seed oil, because the raw materials available in plentiful quantities and can be renewed. In addition, the rubber seed is still lack of utilization, and Indonesia is one of the largest rubbers producing country in the world. The objective of this research is to studied on biodiesel production by esterification process. Parameters used in this study are the ratio of catalyst and temperature and its influence on the characteristics of the resulting biodiesel product. Characterization of rubber seed include acid content number analysis, saponification numbers, density, viscosity, iodine number, type of free fatty acids and triglyceride oils. The results of analysis showed that rubber seed oil content obtained is 50.5%. The results of the GCMS analysis showed that a free fatty acid level in rubber seed is very high. Conversion into bio-diesel oil is obtained by at most 59.91% and lowest 48.24%.

The Rubber Hand Illusion Revisited: Visuotactile Integration and Self-Attribution

Science.gov (United States)

Tsakiris, Manos; Haggard, Patrick

2005-01-01

Watching a rubber hand being stroked, while one's own unseen hand is synchronously stroked, may cause the rubber hand to be attributed to one's own body, to "feel like it's my hand." A behavioral measure of the rubber hand illusion (RHI) is a drift of the perceived position of one's own hand toward the rubber hand. The authors investigated (a) the…

Real estate boom and export performance bust in Croatia

Directory of Open Access Journals (Sweden)

Marina Tkalec

2014-06-01

Full Text Available The goal of this research is to estimate the effect of resource reallocation from the manufacturing to the real estate economic sector on exporting activity in Croatia, a small open post-transition country that experienced a real estate boom during the previous decade. This paper follows the work by Égert and Kierzenkowski (2014 as we test the hypothesis that the real estate boom had an adverse impact on country’s export performance. For that purpose we use quarterly data ranging from 1Q1998 to 3Q2013, and estimate export equations using maximum likelihood and dynamic ordinary least squares estimators of cointegration. Our results indicate that the distortion of relative prices in favor of non-tradable sectors (construction and real estate, which is a direct by-product of the real estate boom, has had stifling effects on export performance. Our results also suggest that ailing cost competitiveness and governments’ inability to implement policies promoting private sector economic development adversely influenced export performance during the period analyzed. The basic conclusion of our research is that the expansion of a non-tradable sector in a country with limited supply of production factors can have a detrimental effect on the ability of the tradable sector to increase its output and compete in international markets.

Research on a haptic sensor made using MCF conductive rubber

International Nuclear Information System (INIS)

Zheng Yaoyang; Shimada, Kunio

2008-01-01

To provide a new composite material having a high electrical sensitivity in the fields of robotics and sensing, a magnetic rubber having network-like magnetic clusters was developed by utilizing a magnetic compound fluid (MCF). MCF rubber with small deformations can provide an effective sensor. In this paper, we report many experiments in which changes of the MCF rubber's resistance were observed when the rubber was compressed and a deformation was generated; we then made a trial haptic sensor using the MCF conductive rubber and performed many experiments to observe changes of the electrical resistance of the sensor. The results of experiments showed that the proposed sensor made with MCF conductive rubber is useful for sensing small amounts of pressure or small deformations

Research on a haptic sensor made using MCF conductive rubber

Energy Technology Data Exchange (ETDEWEB)

Zheng Yaoyang; Shimada, Kunio [Faculty of Symbiotic Systems Science Fukushima University, 1 Kanayakawa, Fukushima 960-1296 (Japan)], E-mail: tei@sss.fukushima-u.ac.jp, E-mail: shimadakun@sss.fukushima-u.ac.jp

2008-05-21

To provide a new composite material having a high electrical sensitivity in the fields of robotics and sensing, a magnetic rubber having network-like magnetic clusters was developed by utilizing a magnetic compound fluid (MCF). MCF rubber with small deformations can provide an effective sensor. In this paper, we report many experiments in which changes of the MCF rubber's resistance were observed when the rubber was compressed and a deformation was generated; we then made a trial haptic sensor using the MCF conductive rubber and performed many experiments to observe changes of the electrical resistance of the sensor. The results of experiments showed that the proposed sensor made with MCF conductive rubber is useful for sensing small amounts of pressure or small deformations.

Research on a haptic sensor made using MCF conductive rubber

Science.gov (United States)

Zheng, Yaoyang; Shimada, Kunio

2008-05-01

To provide a new composite material having a high electrical sensitivity in the fields of robotics and sensing, a magnetic rubber having network-like magnetic clusters was developed by utilizing a magnetic compound fluid (MCF). MCF rubber with small deformations can provide an effective sensor. In this paper, we report many experiments in which changes of the MCF rubber's resistance were observed when the rubber was compressed and a deformation was generated; we then made a trial haptic sensor using the MCF conductive rubber and performed many experiments to observe changes of the electrical resistance of the sensor. The results of experiments showed that the proposed sensor made with MCF conductive rubber is useful for sensing small amounts of pressure or small deformations.

Bearings for the biomass boom

Energy Technology Data Exchange (ETDEWEB)

MacQueen, Duncan

2011-03-15

Biomass energy is booming –– more than two billion people depend on biomass for their energy and the International Energy Agency predicts that biomass' share of the global energy supply will treble by 2050. But in many developing countries it is still regarded as a traditional and dirty solution that is often criminalised, unsustainable and poorly paid. A more sophisticated approach that legalises and secures sustainable production by and for local people could help improve energy security, cut carbon emissions, protect forests and reduce poverty.

The research and application of electricity economic boom model under the constraint of energy conservation and emission reduction

Science.gov (United States)

Chen, Guangyan; Xia, Huaijian; Chen, Meiling; Wang, Dong; Jia, Sujin

2017-10-01

Energy saving and emission reduction policies affects the development of high power industry, thereby affecting electricity demand, so the study of the electricity industry boom helps to master the national economy. This paper analyses the influence of energy saving and emission reduction on power generation structure and pollutant emission in power industry. Through the construction of electricity market composite boom index to indicate electricity boom, using boom index to study volatility characteristics and trend of electricity market. Here we provide a method for the enterprise and the government, that it can infer the overall operation of the national economy situation from power data.

Contact allergy to rubber accelerators remains prevalent

DEFF Research Database (Denmark)

Schwensen, J F; Menné, T; Johansen, J D

2016-01-01

several clinical cases with allergic facial dermatitis to rubber. OBJECTIVES: To evaluate temporal trends of contact allergy to rubber accelerators from the European baseline series in a tertiary patch test clinic in Denmark, and examine associations with anatomical locations of dermatitis. METHODS: Patch...... test and clinical data collected in a Danish tertiary dermatology clinic in Gentofte, Herlev, Copenhagen between 1 January 2005 and 31 December 2014 were analysed. The following rubber accelerators or mixtures in petrolatum from the European baseline patch test series were included: thiuram mix 1.......0%, mercaptobenzothiazole 2.0% and mercapto mix 1.0%. RESULTS: The overall prevalence of contact allergy to rubber accelerators was 3.1% with no significant change during the study period (Ptrend = 0.667). Contact allergy to thiuram mix was the most prevalent and was significantly associated with occupational contact...

Rural North Dakota's oil boom and its impact on social services.

Science.gov (United States)

Weber, Bret A; Geigle, Julia; Barkdull, Carenlee

2014-01-01

Over the last five years, North Dakota has experienced an oil boom based on high oil prices and hydraulic fracturing technologies. This has brought economic expansion and population growth to rural communities that had previously experienced decades of depopulation and economic struggle. Although the state has enjoyed many benefits--especially in juxtaposition to a sluggish national economy--the boom has also meant the arrival of economic refugees and dramatic impacts on largely rural social service systems. In the midst of a rapidly changing situation, available information tends to swing between euphoria over economic success and hysteria about rising crime and shifting cultures. In response, the authors used a primary focus group with county social service directors from across the state and a followup focus group with social workers operating on the edge of oil activity. Grounded in resilience theory, qualitative analysis of the primary focus group, and triangulation of data from other sources, this study provides a more objective report of the housing and social challenges, the benefits of the boom, and the challenges to solutions.

Sugarcane bagasse ash: new filler to natural rubber composite

Directory of Open Access Journals (Sweden)

Renivaldo José dos Santos

2014-12-01

Full Text Available Waste recycling has been the subject of numerous scientific researches regarding the environmental care. This paper reports the redirecting of sugarcane bagasse ash (SBA as new filler to natural rubber (NR/SBA. The NR/SBA composites were prepared using an opened cylinder mixer to incorporate the vulcanization agents and different proportions of residue (SBA. The ash contains about 70-90% of inorganic compounds, with silica (SiO2 being the main compound. The SBA incorporation improved the mechanical properties of the vulcanized rubber. Based on these results, a new use is proposed for the agro-industry organic waste to be implemented in the rubber vulcanization process, aimed at improving the rubber physical properties as well as decreasing the prices of natural rubber composites.

Research and Application Progress of Silicone Rubber Materials in Aviation

Directory of Open Access Journals (Sweden)

HUANG Yanhua

2016-06-01

Full Text Available The research progress of heat resistance, cold resistance, electrical conductivity and damping properties of aviation silicone rubber were reviewed in this article. The heat resistance properties of silicone rubber can be enhanced by changing the molecular structure (main chain, end-group, side chain and molecular weight of the gum and adding special heat-resistance filler. The cold resistance of aviation silicone rubber can be enhanced by adjusting the side chain molecular structure of the gum and the content of different gum chain. The electrical conductivity of silicone rubber can be improved by optimizing, blending and dispersing of conductive particles. The damping property of silicone rubber can be improved by designing and synthesizing of high-molecular polysiloxane damping agent. Furthermore, the application of aviation silicone rubber used in high-low temperature seal, electrical conduction and vibration damping technology are also summarized, and the high performance (for example long-term high temperature resistance, ultralow temperature resistance, high electromagnetic shelding, long-term fatigue resistance vibration damping, quasi constant modulus and so on of special silicone rubber is the future direction of aviation silicone rubber.

Thermal properties of hydrogenated liquid natural rubber

Science.gov (United States)

Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

2015-09-01

Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion.

Thermal properties of hydrogenated liquid natural rubber

International Nuclear Information System (INIS)

Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

2015-01-01

Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion

Thermal properties of hydrogenated liquid natural rubber

Energy Technology Data Exchange (ETDEWEB)

Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

2015-09-25

Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion.

Natural rubber producing plants: An overview | Venkatachalam ...

African Journals Online (AJOL)

... Hevea and also other natural rubber producing species for alternative source of latex production in the near future. Keywords: Alternative rubber sources, biotechnology, breeding, Hevea brasiliensis, Parthenium argentatum, Taraxacum koksaghyz, Ficus bengalensis, Lactuca serriola. African Journal of Biotechnology Vol.

UTILISATION OF RUBBER SEED OL IN THE

African Journals Online (AJOL)

Thermal degradation studies on polyvinyl chloride in the presence of rubber seed oil, epoxidized rubber seed oil and metal ... Epoxidation of RSO was carried out at 29°C using peractic acid ..... impurities such as pigments, Vitamins, sterols ...

Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

Science.gov (United States)

Xu, Tiwen; Jia, Zhixin; Luo, Yuanfang; Jia, Demin; Peng, Zheng

2015-02-01

The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress-strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

Mechanistic study of the rubber-brass adhesion interphase

Science.gov (United States)

Ashirgade, Akshay

Brass-plated steel tire cords form an essential strengthening component of a radial automobile tire. Adhesion between rubber compound and brass-plated steel tire cord is crucial in governing the overall performance of tires. The rubber-brass interfacial adhesion is influenced by the chemical composition and thickness of the interfacial layer. It has been shown that the interfacial layer consists mainly of sulfides and oxides of copper and zinc. This thesis discusses the effect of changes in the chemical composition and the structure of the interfacial layers due to addition of adhesion promoter resins. Grazing incidence X-Ray Diffraction (GIXRD) experiments were run on sulfidized polished brass coupons previously bonded to six experimental rubber compounds. It was confirmed that heat and humidity conditions lead to physical and chemical changes of the rubber-steel tire cord interfacial layer, closely related to the degree of rubber-brass adhesion. Morphological transformation of the interfacial layer led to loss of adhesion after aging. The adhesion promoter resins inhibit unfavorable morphological changes in the interfacial layer thus stabilizing it during aging and prolonging failure. Tire cord adhesion tests illustrated that the one-component resins improved adhesion after aging using a rubber compound with lower cobalt loading. Based on the acquired diffraction profiles, these resins were also found to impede crystallization of the sulfide layer after aging leading to improved adhesion. Secondary Ion Mass Spectrometry (SIMS) depth profiles, SEM micrographs and AFM images strongly corroborated the findings from GIXRD. FTIR was utilized in a novel way to understand the degradation mechanism due to aging. A model for rubber and interfacial layer degradation is proposed to illustrate the effect of aging and the one-component resins. This interfacial analysis adds valuable new information to our understanding of the complex nature of the rubber-brass bonding

Environmental Pollution: Noise Pollution - Sonic Boom. Volume I.

Science.gov (United States)

Defense Documentation Center, Alexandria, VA.

The unclassified, annotated bibliography is Volume I of a two-volume set on Noise Pollution - Sonic Boom in a series of scheduled bibliographies on Environmental Pollution. Volume II is Confidential. Corporate author-monitoring agency, subject, title, contract, and report number indexes are included. (Author/JR)

75 FR 57980 - Polychloroprene Rubber From Japan

Science.gov (United States)

2010-09-23

... INTERNATIONAL TRADE COMMISSION [Investigation No. AA1921-129 (Third Review)] Polychloroprene Rubber From Japan AGENCY: United States International Trade Commission. ACTION: Termination of five-year... of the antidumping duty finding on polychloroprene rubber from Japan would be likely to lead to...

Effects of temperature and thermally-induced microstructure change on hydraulic conductivity of Boom Clay

Directory of Open Access Journals (Sweden)

W.Z. Chen

2017-06-01

Full Text Available Boom Clay is one of the potential host rocks for deep geological disposal of high-level radioactive nuclear waste in Belgium. In order to investigate the mechanism of hydraulic conductivity variation under complex thermo-mechanical coupling conditions and to better understand the thermo-hydro-mechanical (THM coupling behaviour of Boom Clay, a series of permeability tests using temperature-controlled triaxial cell has been carried out on the Boom Clay samples taken from Belgian underground research laboratory (URL HADES. Due to its sedimentary nature, Boom Clay presents across-anisotropy with respect to its sub-horizontal bedding plane. Direct measurements of the vertical (Kv and horizontal (Kh hydraulic conductivities show that the hydraulic conductivity at 80 °C is about 2.4 times larger than that at room temperature (23 °C, and the hydraulic conductivity variation with temperature is basically reversible during heating–cooling cycle. The anisotropic property of Boom Clay is studied by scanning electron microscope (SEM tests, which highlight the transversely isotropic characteristics of intact Boom Clay. It is shown that the sub-horizontal bedding feature accounts for the horizontal permeability higher than the vertical one. The measured increment in hydraulic conductivity with temperature is lower than the calculated one when merely considering the changes in water kinematic viscosity and density with temperature. The nuclear magnetic resonance (NMR tests have also been carried out to investigate the impact of microstructure variation on the THM properties of clay. The results show that heating under unconstrained boundary condition will produce larger size of pores and weaken the microstructure. The discrepancy between the hydraulic conductivity experimentally measured and predicted (considering water viscosity and density changes with temperature can be attributed to the microstructural weakening effect on the thermal volume change

Experimental Investigation of the Mechanical and Durability Properties of Crumb Rubber Concrete.

Science.gov (United States)

Liu, Hanbing; Wang, Xianqiang; Jiao, Yubo; Sha, Tao

2016-03-07

Recycling waste tire rubber by incorporating it into concrete has become the preferred solution to dispose of waste tires. In this study, the effect of the volume content of crumb rubber and pretreatment methods on the performances of concrete was evaluated. Firstly, the fine aggregate and mixture were partly replaced by crumb rubber to produce crumb rubber concrete. Secondly, the mechanical and durability properties of crumb rubber concrete with different replacement forms and volume contents had been investigated. Finally, the crumb rubber after pretreatment by six modifiers was introduced into the concrete mixture. Corresponding tests were conducted to verify the effectiveness of pretreatment methods as compared to the concrete containing untreated crumb rubber. It was observed that the mechanical strength of crumb rubber concrete was reduced, while durability was improved with the increasing of crumb rubber content. 20% replacement of fine aggregate and 5% replacement of the total mixture exhibited acceptable properties for practical applications. In addition, the results indicated that the modifiers had a positive impact on the mechanical and durability properties of crumb rubber concrete. It avoided the disadvantage of crumb rubber concrete having lower strength and provides a reference for the production of modified crumb rubber concrete.

Experimental Investigation of the Mechanical and Durability Properties of Crumb Rubber Concrete

Directory of Open Access Journals (Sweden)

Hanbing Liu

2016-03-01

Full Text Available Recycling waste tire rubber by incorporating it into concrete has become the preferred solution to dispose of waste tires. In this study, the effect of the volume content of crumb rubber and pretreatment methods on the performances of concrete was evaluated. Firstly, the fine aggregate and mixture were partly replaced by crumb rubber to produce crumb rubber concrete. Secondly, the mechanical and durability properties of crumb rubber concrete with different replacement forms and volume contents had been investigated. Finally, the crumb rubber after pretreatment by six modifiers was introduced into the concrete mixture. Corresponding tests were conducted to verify the effectiveness of pretreatment methods as compared to the concrete containing untreated crumb rubber. It was observed that the mechanical strength of crumb rubber concrete was reduced, while durability was improved with the increasing of crumb rubber content. 20% replacement of fine aggregate and 5% replacement of the total mixture exhibited acceptable properties for practical applications. In addition, the results indicated that the modifiers had a positive impact on the mechanical and durability properties of crumb rubber concrete. It avoided the disadvantage of crumb rubber concrete having lower strength and provides a reference for the production of modified crumb rubber concrete.

Simulation work of fatigue life prediction of rubber automotive components

International Nuclear Information System (INIS)

Samad, M S A; Ali, Aidy

2010-01-01

The usage of rubbers has always been so important, especially in automotive industries. Rubbers have a hyper elastic behaviour which is the ability to withstand very large strain without failure. The normal applications for rubbers are used for shock absorption, sound isolation and mounting. In this study, the predictions of fatigue life of an engine mount of rubber automotive components were presented. The finite element analysis was performed to predict the critical part and the strain output were incorporated into fatigue model for prediction. The predicted result shows agreement in term of failure location of rubber mount.

Performance Study of the Natural Rubber Composite with Clay Minerals

International Nuclear Information System (INIS)

Nyo Nyo Myint; Tin Tin Aye; Kyaw Myo Naing; Nyunt Wynn

2008-03-01

The preparation, characterization and some applications of natural rubber clay composite have been studied. This study investigated the possibility of natural rubber latex to replace some part of natural clays. In formulation of rubber clay composite from natural rubber latex and various clay minerals, three main steps were involved (i) preparation of latex cream (ii) prevulcanization of latex cream (iii) mixing vulcanized latex compound, with other ingredients. In each step, several parameters have been carefully investigated to optimize the performance of natural rubber clay composite production. The composite products were of better quality and can be considered to be more cost effective.

Use of rubber crumb for preparation of asphalt-concrete mixtures

Directory of Open Access Journals (Sweden)

Yerbol Tileuberdi

2012-03-01

Full Text Available In this article use of rubber crumb from spent tire for preparation of rubber-bitumen compounds is investigated. Then the rubber-bitumen compositions are used in composition of asphalt concrete mixes .

Proceedings of the Rubber Association of Canada's 7. biennial 2006 rubber recycling symposium : changing concepts

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

Rising energy costs and concerns over the environment have contributed to a renewed focus on recycling for many governments and industries. This conference examined recent trends affecting rubber recycling activities as well as the legislative environment and its impacts on future recycling activities. Major rubber recycling markets were reviewed, and emerging product ideas were evaluated. Industry stewardship model and governance models were discussed. The impacts of new advances in tire technology and manufacturing on the rubber recycling industry were also investigated. Issues concerning fixed tipping fees and incentive structures were discussed, and effective management strategies for the recycling of large off-the-road tires were evaluated. Tire-derived fuel (TDF) is the largest market in North America for scrap tires, and TDF may continue to grow as a result of rising fossil fuel costs. Issues and challenges related to the introduction of TDF to new communities were discussed. New developments in tire derived aggregates (TDA) and ground rubber were also reviewed. Twenty-eight presentations were given at this conference, 3 of which were catalogued separately for inclusion in this database. refs., tabs., figs.

The geochemical behaviour of selenium in the Boom Clay system - a XANES and EXAFS study

International Nuclear Information System (INIS)

2S, KULeuven, B-3001Leuven (Belgium))" data-affiliation=" (Center for surface Chemistry and Catalysis - M2S, KULeuven, B-3001Leuven (Belgium))" >Breynaert, Eric; 2S, KULeuven, B-3001Leuven (Belgium))" data-affiliation=" (Center for surface Chemistry and Catalysis - M2S, KULeuven, B-3001Leuven (Belgium))" >Dom, Dirk; 2S, KULeuven, B-3001Leuven (Belgium))" data-affiliation=" (Center for surface Chemistry and Catalysis - M2S, KULeuven, B-3001Leuven (Belgium))" >Vancluysen, Jacqueline; 2S, KULeuven, B-3001Leuven (Belgium))" data-affiliation=" (Center for surface Chemistry and Catalysis - M2S, KULeuven, B-3001Leuven (Belgium))" >Kirschhock, Christine E.A.; 2S, KULeuven, B-3001Leuven (Belgium))" data-affiliation=" (Center for surface Chemistry and Catalysis - M2S, KULeuven, B-3001Leuven (Belgium))" >Maes, Andre; Scheinost, Andreas C.

2010-01-01

Document available in extended abstract form only. In Belgium, the Boom Clay formation is studied as a reference host formation for the geological disposal of high-level and long-lived radioactive waste for more than 30 years. This formation mainly consists of mixed clay minerals (illite, inter-stratified illite-smectite), pyrite and immobile and dissolved natural organic matter. Since it provides good sorption capacities, very low permeability, and chemically reducing conditions due to the presence of pyrite (FeS 2 ), the Boom clay formation itself is considered to be the main barrier preventing radionuclide migration from the geological repository. Within this concept for geological storage Se 79 has been identified as one of the critical elements contributing to the final dose to man. Although the sorption and migration behaviour of Se in the Boom Clay system has been thoroughly studied, the speciation of Se in the Boom Clay system has never been identified spectroscopically. In all previous studies, the interpretation of the behaviour of Se in Boom Clay conditions has always been based on circumstantial evidence such as solubility measurements or comparison with the spectroscopically identified speciation of Se in model systems. Based on the XANES analysis, selenite is transformed into Se 0 confirming the previously proposed reduction of selenite in the Boom Clay system. Combination of the mass-balance for Se with the results from linear combination analysis of the XANES spectra provided new evidence for the sorption-reduction mechanism proposed to explain the interaction between Se(IV) and the BC solid phase. In addition, evidence was found that that the fate of Se(IV) in the BC system is completely dominated by its interaction with pyrite present in the Boom Clay. The combined EXAFS analysis of Se in Se 0 reference phases (hexagonal, monoclinic, Se-loaded pyrite) allowed to elucidate further details on the short-range structure of the reaction products formed

The water-food nexus of natural rubber production

Science.gov (United States)

Chiarelli, D. D.; Rosa, L.; Rulli, M. C.; D'Odorico, P.

2017-12-01

The increasing global demand for natural rubber (100% increase in the last 15 years) is for most part met by Malaysia and Indonesia, and - to a lesser extent - other countries in south-east Asia and Africa. The consequent expansion of rubber plantation has often occurred at the expenses of agricultural land for staple food, particularly in southeast Asia, where most of the land suitable for agriculture is already harvested for food crops or other uses. Here we investigate the extent to which the ongoing increase in rubber production is competing with the food system and affecting the livelihoods of rural communities in the areas of production and their appropriation of natural resources, such as water. We also investigate to what extent the expansion of rubber plantations is taking place through large scale land acquisitions (LSLAs) and evaluate the impacts on rural communities. Our results show how rubber production has strong environmental, social and economic impacts. Despite their ability to bring employment and increase the average income of economically disadvantaged areas, rubber plantations may threaten the local water and food security and induce a loss of rural livelihoods, particularly when the new plantations result from LSLAs that displace semi-subsistence forms of production thereby forcing the local populations to depend on global markets.

Aging Depth Test of Rubber Blocks by Accelerated Thermal Oxidation Test

International Nuclear Information System (INIS)

Park, Junhee; Choun, Young-Sun; Kim, Min Kyu

2015-01-01

In this study, the accelerated thermal oxidation tests of rubber block were performed to investigate the aging depth of rubber bearing. From the tests, it was found the critical aging depth in rubber block. Also the property variation of rubber was investigated along the depth. The deterioration pattern from the aging depth tests was found from surface to inside and the critical aging depth was to be about 10 mm. The analytical model for rubber bearing with aging can be developed based on the relationship between the property variation and aging depth investigated from this study. The mechanical properties of rubber bearings were changed with time. Because the aging effect of rubber material was generally higher than that of other structure materials it is needed that the aging properties of seismically isolators should be evaluated to ensure the safety of seismically isolated nuclear power plants (NPPs) over the lifetime. NRC and ASCE required the tests of seismically isolators for investigating the aging properties. JNES also required the seismic response analysis for the seismically isolated NPPs when the properties of seismically isolators were extremely changed. If the aging properties of seismically isolators such as rubber bearings are evaluated by analysis the analytical model of seismically isolators should be developed considering aging effect of rubber material. From the previous research, it was reported that the behavior of aged rubber material mainly affected by temperature and oxidation. The material properties between surface and inside can be different by the oxidation of rubber. Therefore, the aging depth should be investigated for exactly evaluating the seismic behavior of aged rubber bearing. The aging depth of rubber baring was not influenced by the size of seismically isolators but environment condition. Therefore, the detail analysis considering aging depth was not required for NPPs with large seismically isolators. But the seismic response

30 CFR 77.606-1 - Rubber gloves; minimum requirements.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Rubber gloves; minimum requirements. 77.606-1... COAL MINES Trailing Cables § 77.606-1 Rubber gloves; minimum requirements. (a) Rubber gloves (lineman's gloves) worn while handling high-voltage trailing cables shall be rated at least 20,000 volts and shall...

Características del ambiente marino frente a la costa peruana

OpenAIRE

Morón Antonio, Octavio

2000-01-01

El ambiente marino frente al Perú es modificado considerablemente por eventos transcendentes de características opuestas: El Niño y La Niña, los mismos que se presentan alternadamente, con diferente intensidad y duración. La temperatura presenta sus máximos y mínimos valores en verano e invierno, respectivamente;ambos E:xtremos dela salinidad se registran en el verano; los nutrientes presentan sus mínimos valores en verano y máximos en el invierno, intensificándose el afloramiento. Frente...

Boom in boarfish abundance: insight from otolith analysis

DEFF Research Database (Denmark)

Coad, Julie Olivia; Hüssy, Karin

2012-01-01

The boarfish Capros aper is a pelagic shoaling species widely distributed along the Northeast Atlantic continental shelf. In recent years, this species has experienced a dramatic boom in abundance in the Bay of Biscay and Celtic Sea. This study aims at resolving the mechanisms responsible for thi...

Recycling of rubber tires in asphalt paving materials

Energy Technology Data Exchange (ETDEWEB)

Piggott, M.R.; Woodhams, R.T.

1979-01-01

It has been known that the addition of rubber to asphalt used in paving will produced markedly superior road surfaces. Partly because of cost and because of the nonconventional paving techniques necessary, rubber has been largely ignored as a practical paving additive except in special cases. However, the large accumulation of old tires existing today provides a ready source for suitable rubber. If ground into a fine powder, this rubber can be mixed in a conventional pug mill along with sand, stone and asphalt to produce a hot mix which can be aplied in the normal manner without any special techniques. The extra cost of such modification is only 1% of a typical paving contract, whereas the advantages include lower maintenance cost, more durable road surface, and elimination of unwanted waste tires. This report has been prepared to assist civic and other authorities in the development of improved road surfacing formulations through the reuse of old tires. It includes the results of paving trials in Toronto and laboratory evaluations. These tests show that the addition of powdered rubber to asphalt paving materials markedly improves the durability and crack resistance, particularly at low temperatures. Additives in the rubber impart good strength retention in the presence of moisture. The toughness increases with age due to a slow interaction of the rubber with the asphalt which is accompanied by an increase in viscosity. As a result, performance is also enhanced at high temperatures and helps to minimize pavement distortions due to hot weather and traffic. 16 refs., 18 figs., 2 tabs.

Chrome-tanned leather shavings as a filler of butadiene-acrylonitrile rubber.

Science.gov (United States)

Przepiórkowska, A; Chrońska, K; Zaborski, M

2007-03-06

The noxious wastes from the tanning industry such as chrome-tanned leather shavings were used as the only filler of rubber mixes containing carboxylated butadiene-acrylonitrile rubber (XNBR) or butadiene-acrylonitrile rubber (NBR), and a dispersing agent Limanol PEV (Schill & Seilacher). The best form addition of leather powder to the rubber mixes is mixed the waste protein with zinc oxide. The leather powder added to the rubber mixes improves the mechanical properties: tensile strength (T(s)), elongation at break (epsilon(b)) and increase the cross-linking density of carboxylated XNBR and NBR rubber mixes. Satisfactory results of these studies are presented in this work.

Soft matter: rubber and networks

Science.gov (United States)

McKenna, Gregory B.

2018-06-01

Rubber networks are important and form the basis for materials with properties ranging from rubber tires to super absorbents and contact lenses. The development of the entropy ideas of rubber deformation thermodynamics provides a powerful framework from which to understand and to use these materials. In addition, swelling of the rubber in the presence of small molecule liquids or solvents leads to materials that are very soft and ‘gel’ like in nature. The review covers the thermodynamics of polymer networks and gels from the perspective of the thermodynamics and mechanics of the strain energy density function. Important relationships are presented and experimental results show that the continuum ideas contained in the phenomenological thermodynamics are valid, but that the molecular bases for some of them remain to be fully elucidated. This is particularly so in the case of the entropic gels or swollen networks. The review is concluded with some perspectives on other networks, ranging from entropic polymer networks such as thermoplastic elastomers to physical gels in which cross-link points are formed by glassy or crystalline domains. A discussion is provided for other physical gels in which the network forms a spinodal-like decomposition, both in thermoplastic polymers that form a glassy network upon phase separation and for colloidal gels that seem to have a similar behavior.

Optical and Thermal Stability of Oligofluorene/Rubber Luminescent Blend.

Science.gov (United States)

Barbosa, Camila G; Faez, Roselena; Péres, Laura O

2016-09-01

This paper proposes to obtain homogeneous and stable blends of oligo(9,9-dioctylfluorene)-co-phenylene (OF), a conjugated oligomer with strong tendency of formation of excimers in the solid state, and nitrile rubber (NBR). This rubber protection reduces the formation of polymer excimers in the films. The fluorene oligomer was synthesized via Suzuki reaction and incorporated in the nitrile rubber. The films were formed by spin coating and casting techniques on the proportions of 1, 5, 10, 20 and 50 % (w/w) of OF in the nitrile rubber (NBR). The structural, optical and thermal properties of the films were evaluated with infrared, UV-Vis, fluorescence and thermogravimetry, respectively. The nitrile rubber proved to be essential for the preparation of homogeneous and stable films, since it was not possible to obtain films with only fluorene using the above-mentioned techniques. Furthermore, luminescent properties of OF are unchanged and the excimers formation in the solid state decrease suggesting the efficiency of nitrile rubber as the matrix for making films.

Gamma-radiation effect on thermal ageing of butyl rubber compounds

Energy Technology Data Exchange (ETDEWEB)

Scagliusi, Sandra R.; Cardoso, Elizabeth C.L.; Lugao, Ademar B., E-mail: srscagliusi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

Butyl rubber has a comprehensive use in sealing systems, especially in tires inner tubes, due to their low permeability to gases. So, it is required that butyl rubber compounds show a better performance, more and more. Butyl rubber is provided with excellent mechanical properties and oxidation resistance. Besides showing these properties, radiation exposures impart modifications in physical-chemical and morphological properties on butyl rubber materials. When exposed to gamma-radiation, rubbers suffer changes in their mechanical and physical properties, caused by material degradation. The major radiation effect in butyl rubbers is chain scission; besides, ageing promotes too the same effect with further build-up of free radicals. This work aims to the study of gamma-radiation in physical-chemical properties of butyl rubber subjected to thermal ageing. Doses used herein were: 25 kGy, 50 kGy, 100 kGy, 150 kGy and 200 KGy. Samples were evaluated before and after ageing according to traditional essays, such as: hardness, tensile strength and elongation at break. From accomplished assessments it is possible to affirm that at doses higher than 50 kGy it was observed a sharp decreasing in butyl rubber physical-chemical properties, before and after exposure to ageing. (author)

Gamma-radiation effect on thermal ageing of butyl rubber compounds

International Nuclear Information System (INIS)

Scagliusi, Sandra R.; Cardoso, Elizabeth C.L.; Lugao, Ademar B.

2015-01-01

Butyl rubber has a comprehensive use in sealing systems, especially in tires inner tubes, due to their low permeability to gases. So, it is required that butyl rubber compounds show a better performance, more and more. Butyl rubber is provided with excellent mechanical properties and oxidation resistance. Besides showing these properties, radiation exposures impart modifications in physical-chemical and morphological properties on butyl rubber materials. When exposed to gamma-radiation, rubbers suffer changes in their mechanical and physical properties, caused by material degradation. The major radiation effect in butyl rubbers is chain scission; besides, ageing promotes too the same effect with further build-up of free radicals. This work aims to the study of gamma-radiation in physical-chemical properties of butyl rubber subjected to thermal ageing. Doses used herein were: 25 kGy, 50 kGy, 100 kGy, 150 kGy and 200 KGy. Samples were evaluated before and after ageing according to traditional essays, such as: hardness, tensile strength and elongation at break. From accomplished assessments it is possible to affirm that at doses higher than 50 kGy it was observed a sharp decreasing in butyl rubber physical-chemical properties, before and after exposure to ageing. (author)

Preparation of vinyl acetate grafted natural rubber by irradiation method

Energy Technology Data Exchange (ETDEWEB)

Porntrairat, A.; Pattamaprom, C. [Center of Excellence on Natural Rubber Technology, Department of Chemical Engineering, Faculty of Engineering, Thammasat University, Pathumthani 12120 (Thailand)

2016-03-09

Improvement in properties of natural rubber could be done by several methods. In this research, gamma radiation technique, which is simple, accurate, easy to control and clean, was applied to enhance the properties of natural rubber (NR) in latex state. The purpose of this research is to study the appropriate condition for preparing grafted natural rubber latex by using irradiation method. Vinyl acetate monomers (VAc) were grafted onto natural rubber latex (NR-g-PVAc) at 0-10 kGys by gamma radiation from Cobalt-60 source at room temperature. Physical properties of grafted natural rubber such as chloroform number, swelling ratio and gel content were measured. The VAc content of NR-g-PVAc was investigated by titration and visualized by FTIR spectroscopy. The FTIR spectra of NR-g-PVAc prepared at 0-10 kGys showed characteristic peaks of the vinyl acetate confirming that VAc could be grafted onto natural rubber molecular chains effectively under appropriate irradiation conditions. From the result, radiation grafting was found to be a useful technique for grafting of vinyl acetate onto natural rubber.

Rheological testing of crumb rubber modified bitumen

CSIR Research Space (South Africa)

Mturi, GAJ

2011-08-01

Full Text Available used to analyse crumb rubber modified (CRM) bitumen is that the specified gap setting in the configuration of the DSR between the upper and lower test platens is too small to accommodate crumb rubber particles. DSR testing of CRM bitumen therefore...

New type of liquid rubber and compositions based on it.

Science.gov (United States)

Semikolenov, S V; Nartova, A V; Voronchikhin, V D; Dubkov, K A

2014-11-01

The new method for producing the functionalized polymers and oligomers containing carbonyl C=O groups is developed. The method is based on the noncatalytic oxidation of unsaturated rubbers by nitrous oxide (N2O) at 180-230 °С. The proposed method allows obtaining the new type of functionalized rubbers-liquid unsaturated polyketones with regulated molecular weight and concentration of C=O groups. The influence of the liquid polyketone addition on properties of rubber-based composites is investigated. The study indicates good prospects of using the liquid polyketones for the improvement of properties and operating characteristics of the various types of rubbers and the rubber-cord systems.

Adaptive neuro-fuzzy inference system for forecasting rubber milk production

Science.gov (United States)

Rahmat, R. F.; Nurmawan; Sembiring, S.; Syahputra, M. F.; Fadli

2018-02-01

Natural Rubber is classified as the top export commodity in Indonesia. Its high production leads to a significant contribution to Indonesia’s foreign exchange. Before natural rubber ready to be exported to another country, the production of rubber milk becomes the primary concern. In this research, we use adaptive neuro-fuzzy inference system (ANFIS) to do rubber milk production forecasting. The data presented here is taken from PT. Anglo Eastern Plantation (AEP), which has high data variance and range for rubber milk production. Our data will span from January 2009 until December 2015. The best forecasting result is 1,182% in term of Mean Absolute Percentage Error (MAPE).

Shear modulus and damping ratio of natural rubber containing carbon nanotubes

Science.gov (United States)

Ismail, R.; Ibrahim, A.; Rusop, M.; Adnan, A.

2018-05-01

This paper presents the results of an investigation into the potential application of Natural rubber (NR) containing Carbon Nanotubes (CNTs) by measuring its shear modulus and damping ratio. Four different types of rubber specimens which fabricated with different MWCNT loadings: 0 wt% (pure natural rubber), 1 wt%, 3 wt%, and 5 wt%. It is observed that the shear modulus and damping ratio of CNTs filled rubber composites are remarkably higher than that of raw rubber indicating the inherent reinforcing potential of CNTs.

Use of Diels-Alder Chemistry for Thermoreversible Cross-Linking of Rubbers : The Next Step toward Recycling of Rubber Products?

NARCIS (Netherlands)

Polgar, L. M.; van Duin, M.; Broekhuis, A. A.; Picchioni, F.

2015-01-01

A proof of principle for the use of Diels-Alder chemistry as a thermoreversible cross-linking tool for rubber products is demonstrated. A commercial ethylene-propylene rubber grafted with maleic anhydride has been thermoreversibly cross-linked in two steps. The pending anhydride rings were first

Evaluation of rubber seal products for gamma facilities

International Nuclear Information System (INIS)

Sobhy, M.S.; Shafy, M.A.; Shahin, F.

2005-01-01

Ageing behavior by employing the prolonged exposures of high-energy radiation such as gamma-rays on the physicomechanical properties of some rubber seal products are studied. The proposed binary-rubber blends, SBR/NBR, EPDM/NBR and EPDM/EPM. have overcome their problem of inhomogeneity and incompatibility between the two rubber phases. Such enhancements are acquired by either the replacement of part of NBR by SBR during mastication, or the incorporation of maleic anhydride. Results show that the EPDM/EPM rubber blend has possessed the radiation resistance property towards the deterioration due to higher gamma-irradiation dose. The SEM images have c early observed the role of the used antioxidant, where a thin film is usually produced, degraded; with the appearance of surface cracks, and repaired with further gamma-irradiation up to high doses. Such enhancement is necessary for the definition of the requirements to be put on rubber seal materials. Finally, these products ought to assure the quality control in production and evaluate their application suitability that may employ in the pneumatic system in gamma facility

Radiation cured silicone rubber articles

International Nuclear Information System (INIS)

DuPont, J.G.; Goodwin, P.A.

1984-01-01

A process for making radiation cured silicone rubber articles is disclosed wherein a hydroxyl-terminated polysilaxane having a molecular weight from about 50,000 to about 2,000,000, optionally modified by mixing with up to 85% of an end-stopped silicone rubber, is mixed with from about 10 to about 70 parts per hundred of rubber of a finely divided silica filler with a particle size in the reinforcing range and other inert fillers as determined by desired final properties; the composition so prepared is formed into the desired shape at room temperature; the article so formed is precured to improve the mechanical properties of the material with which it is made by exposure to ammonia gas, ammonium hydroxide, or to the vapors or solutions of a volatile amine at room temperature; and the precured article is irradiated with high energy electrons or gamma radiation to effect a permanent cure of the material from which the article is formed

Strength of mortar containing rubber tire particle

Science.gov (United States)

Jusoh, M. A.; Abdullah, S. R.; Adnan, S. H.

2018-04-01

The main focus in this investigation is to determine the strength consist compressive and tensile strength of mortar containing rubber tire particle. In fact, from the previous study, the strength of mortar containing waste rubber tire in mortar has a slightly decreases compare to normal mortar. In this study, rubber tire particle was replacing on volume of fine aggregate with 6%. 9% and 12%. The sample were indicated M0 (0%), M6 (6%), M9 (9%) and M12 (12%). In this study, two different size of sample used with cube 100mm x 100mm x 100mm for compressive strength and 40mm x 40mm x 160mm for flexural strength. Morphology test was conducted by using Scanning electron microscopic (SEM) were done after testing compressive strength test. The concrete sample were cured for day 3, 7 and 28 before testing. Results compressive strength and flexural strength of rubber mortar shown improved compare to normal mortar.

A Boom in Boomerangs

Science.gov (United States)

1992-01-01

Ted Bailey, a highly-ranked international boomerang designer and thrower, used information from a variety of NASA technical reports on aerodynamics and low-speed airfoils to design more competitive boomerangs. Because the boomerang is essentially an airfoil like an airplane wing, the technology transferred effectively and even contributed to the 1981 American victory over Australian throwers. In 1985, using four NASA reports, Bailey designed a new MTA (maximum time aloft) boomerang that broke the one-minute barrier, enabled throwers to throw and catch in less than three minutes and allowed competitors to complete the difficult "Super Catch" - five throw/catch sequences after launching the original boom while it is still aloft. Bailey is now considering other boomerang applications.

Effects of preparation process on performance of rubber modified asphalt

Science.gov (United States)

Liu, Hanbing; Luo, Guobao; Wang, Xianqiang; Jiao, Yubo

2015-06-01

The rational utilization of waste rubber tire is essential for the environmental protection. Utilizing rubber particles to modify asphalt can not only improve asphalt performance, but also help the recycling of waste materials. Considering the effect of different preparation process parameters on the performance of rubber modified asphalt, this paper analyzes the effects of the shear temperature, shear time and shear rate on the performance of rubber modified asphalt, and provided a reference for its preparation.

Use of rubber shreds to enhance attenuation of railway sub-ballast layers made of unbound aggregates; Uso de partículas de caucho para mejorar la capacidad de atenuación de capas granulares de subbalasto en ferrocarriles

Energy Technology Data Exchange (ETDEWEB)

Hidalgo-Signes, C.; Garzón-Roca, J.; Grima-Palop, J.M.; Insa-Franco, R.

2017-07-01

One of the approaches for solving the problem of induced vibrations in railways is by slightly modifying the materials that form the track. A study is presented of the attenuation capacity of mixes composed of granular soil and rubber shreds when used as sub-ballast (the layer located immediately below the ballast layer). Rubber shreds are obtained from scrap tyres, a troublesome waste material whose reuse and recycling is necessary. A series of mixes of granular soil and rubber shreds with rubber contents of between 1% and 10% are submitted to hammer impact tests to study their response to dynamic excitation. Results reveal that mixing rubber shreds with granular soil increases damping ratios, thus demonstrating the potential of the proposed mixes for attenuating vibration. [Spanish] Una de las posibles formas de resolver el problema de las vibraciones inducidas por el ferrocarril es llevando a cabo una ligera modificación de los materiales que forman la vía. En este artículo, se presenta un estudio de la capacidad de atenuación de mezclas compuestas por zahorras y partículas de caucho para ser usadas como sub-balasto (capa localizada bajo el balasto). Las partículas de caucho se obtienen a partir de neumáticos fuera de uso, un material problemático cuya reutilización y reciclaje es cada vez más necesario. Las mezclas de zahorra-caucho, con un contenido entre el 1% y 10%, se someten a una serie de ensayos dinámicos mediante impacto con martillo, estudiando su respuesta frente a la excitación dinámica. Los resultados revelan que la mezcla de partículas de caucho con zahorras aumenta el coeficiente de amortiguamiento, lo que muestra el potencial que poseen las mezclas propuestas para la atenuación de vibraciones.

Characterizing Tire Crumb Rubber for Exposure Assessment

Science.gov (United States)

Tire crumb rubber derived from recycled tires is widely used as infill material in synthetic turf fields in the United States. An estimated 95% of the over 12,000 installed fields in the U.S. use tire crumb rubber infill alone or mixed with sand or alternative materials. Concerns...

Endurance test report of rubber sealing materials for the containment vessel

International Nuclear Information System (INIS)

Yamamoto, R.; Watanabe, K.; Hanashima, K.

2015-01-01

In the event of a nuclear power plant accident such as a core meltdown and a cooling system failure, the containment contains radioactive materials released from the reactor pressure vessel to reduce the activity of the radioactive materials and the effects of radiation in the vicinity of the plant. Since high sealing performance and high pressure resistance are required of the containment, a silicone or EPDM rubber gasket with high heat and radiation resistance is used for the sealing of the sealing boundary of the containment. In recent years, it has been shown that a large amount of steam is released into the containment in the case of a severe accident. Consequently, radiation resistance at high temperature as well as steam resistance is required of the rubber gasket placed at the sealing boundary. However, the steam resistance of silicone rubber is not necessarily as good as that of EPDM rubber. Therefore, it is necessary to evaluate the sealing characteristics of rubber gaskets in such a degrading environment in a severe accident. O. Kato et al. [1] conducted a study on the degradation status of rubber gaskets and their application limits at high temperature. However, few studies have evaluated rubber gaskets in high-temperature radiation and steam environments. In this study, we degraded silicone rubber and EPDM rubber used for the containment in the high-temperature radiation and steam environments expected to occur in a severe accident and evaluated the useful life of the rubber as a sealing material by estimating the change in its performance as a sealing material from the change in permanent compressive strain in the rubber. (author)

On the thermal behaviour of Boom clay

International Nuclear Information System (INIS)

Delage, P.; Cui Yu Jun; Sultan, N.

2004-01-01

When temperature is increased, the various phenomena that occur in a saturated natural potential host clay for nuclear waste disposal (Boom clay from SCK-CEN in Mol, Belgium) were experimentally investigated in a temperature controlled high stress triaxial cell. Firstly, the pore pressure build-up due to the difference in thermal dilation of both water and minerals was investigated through thermal consolidation tests. Interesting information was obtained about the dissipation of thermally induced pore pressure in Boom clay, based on the standard Terzaghi consolidation theory. Secondly, the volume change behaviour in drained conditions (i.e. under a very slow temperature increase) confirmed that the clay overconsolidation ratio (OCR) controlled the nature of the volume changes. Whereas overconsolidated soils use to dilate as any material when temperature is elevated, normally consolidated soils present a decrease in volume, which is less common. The principles of a coupled thermo-elasto-plastic model that was specifically developed to model this particular behaviour are finally presented. Obviously, it appears necessary to account in detail for these thermal phenomena in order to properly understand the response of the geological barrier in the near field once nuclear waste has been stored. (orig.)

Analysis of Offshore Knuckle Boom Crane - Part Two: Motion Control

Directory of Open Access Journals (Sweden)

Morten K. Bak

2013-10-01

Full Text Available In this paper design of electro-hydraulic motion control systems for offshore knuckle boom cranes is discussed. The influence of the control valve bandwidth along with the ramp time for the control signal are investigated both analytically with simplified system models and numerically with an experimentally verified crane model. The results of both types of investigations are related to general design rules for selection of control valves and ramp times and the relevance of these design rules is discussed. Generally, they are useful but may be too conservative for offshore knuckle boom cranes. However, as demonstrated in the paper, the only proper way to determine this is to evaluate the motion control system design by means of simulation.

Caltrans use of scrap tires in asphalt rubber products: a comprehensive review

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Haiping Zhou

2014-02-01

Full Text Available The California Department of Transportation (Caltrans has been using scrap tire rubber in asphalt pavements since the 1970s in chip seals and the 1980s in rubberized hot mix asphalt(RHMA. Both the wet (field blend and dry processes were used in early trials. Caltrans has also used rubber modified binders containing both crumb rubber modifier and polymer modifier that could be manufactured at a refinery facility, a terminal blend wet process. Since the beginning of this century, Caltrans increased the use of scrap tire rubber in paving projects and invested considerable resources in developing technically sound, cost effective, and environmentally friendly strategies for using scrap tire rubber in roadway applications. By the end of year 2010, approximately 31%of all hot mix asphalt (HMA placed by Caltrans was rubberized HMA, roughly 1.2 million tons. Caltrans efforts in using asphalt rubber products were also demonstrated in its research and technology development. These included the construction of two full-scale field experiments, five warranty projects, and an accelerated pavement study using a heavy vehicle simulator. Additionally, terminal blend asphalt rubber and rubberized warm mix asphalts began to be experimented on trial basis. This paper provides a comprehensive review of Caltrans experience over four decades with asphalt rubber products. Current practices and future outlook are also discussed.

Devulcanization of Waste Tire Rubber Using Amine Based Solvents and Ultrasonic Energy

Directory of Open Access Journals (Sweden)

Walvekar Rashmi

2018-01-01

Full Text Available This research project focuses on an alternative pathway of devulcanizing waste tire rubber by using amine based chemicals. Waste tire rubbers are known to be as toxic, non-degradable material due to their vulcanized crosslink carbon structure, and disposing of such waste could impose hazardous impacts on the environment. The current rubber recycling methods that are practiced today are rather uneconomical, non-environmentally friendly, and also producing recycled rubber with low quality due to the alteration in the main polymeric chains of waste rubber. This project aims to answer the question of whether the usage of amine can produce high quality rubber, where the properties of recycled rubber is almost the same as new/virgin rubber. With known potential of amine, it is a challenge for the chemical to selectively cleave the sulfur bonds without affecting the main carbon backbone chain in the rubber structure and diminishing much of the rubber properties. To study this research, amine-treated rubber must undergo devulcanisation process by applying heat and sonication energy. Then, the properties of the amine-treated rubber were determined through a set of characterization tests and analysis which are: gel content test to determine the weight of rubber before and after devulcanization, the thermogravimetric analysis (TGA to determine the thermal degradation and stability of rubber, and Fourier Transform Infrared Spectroscopy (FTIR to determine any structural change of the rubber. In this research so far, the first two preliminary analysis tests have been performed. The gel content test has shown that tertiary amine samples possessed a lower gel content (% of (77 – 63 %, compared to primary amine samples (falls within the range of 80%, as well as the TGA test in which tertiary amine samples degrade faster than primary amine samples (suggesting a higher degree of rubber structure breakdown. For each type of amine, the concertation of amine did

Effect of Graphite on the Properties of Natural Rubber

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Auda jabber Braihi

2016-09-01

Full Text Available Natural rubber-graphite composites (0, 1, 2, 3, 4 pphr graphite were prepared on a laboratory two-roll mill. Swelling measurements were used to evaluate the impacts of graphite on the properties of natural rubber. Swelling results showed that the volume fraction of natural rubber in the swollen gel, the interaction parameter, and the cross-link density decreased by increasing graphite loadings, while the average molecular weight of natural rubber between cross-links increased. Vulcanization results showed that only scorch time parameter increased with increasing graphite loadings, while other parameters (Max. torque, Min. torque, cure rate and cure rate index decreased. Both thermal and AC conductivities increased.

Pilot Test of a Novel Method for Assessing Community Response to Low-Amplitude Sonic Booms

Science.gov (United States)

Fidell, Sanford; Horonjeff, Richard D.; Harris, Michael

2012-01-01

A pilot test of a novel method for assessing residents annoyance to sonic booms was performed. During a two-week period, residents of the base housing area at Edwards Air Force Base provided data on their reactions to sonic booms using Smartphone-based interviews. Noise measurements were conducted at the same time. The report presents information about data collection methods and about test participants reactions to low-amplitude sonic booms. The latter information should not be viewed as definitive for several reasons. It may not be reliably generalized to the wider U.S. residential population (because it was not derived from a representative random sample) and the sample itself was not large.

Rheological Properties of Rubber Compounds with Finely Divided Carbon Additives

Science.gov (United States)

Shashok, Zh. S.; Prokopchuk, N. R.; Vishnevskii, K. V.; Krauklis, A. V.; Borisevich, K. O.; Borisevich, I. O.

2018-01-01

A study has been made of the influence of three different nanomaterials: of the starting material, and also of those functionalized by amine and oxygen-containing groups, on the properties of elastomer compositions based on rubbers for special purposes. As the elastomer matrix, use was made in one case of a rubber compound based on BNKS-18 butadiene-nitrile rubber and in the other, of a combination of two grades of butadiene-nitrile rubber (BNKS-18 + BNKS-28 in a 50:50 ratio), which differed by the amount of the bound nitrile of acrylic acid. To determine the degree of interaction between the additives and the elastomer matrix, the authors carried out multiple tests of the rubber compounds. The indices of plastoelastic properties of the rubber compounds and the qualitative characteristics of distribution of the filler (elastic modulus at small deformation amplitudes and the shear modulus under large deformation) and the difference in these indices (complex dynamic modulus) alike have been determined.

Comparative Proteomics of Rubber Latex Revealed Multiple Protein Species of REF/SRPP Family Respond Diversely to Ethylene Stimulation among Different Rubber Tree Clones

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Zheng Tong

2017-05-01

Full Text Available Rubber elongation factor (REF and small rubber particle protein (SRPP are two key factors for natural rubber biosynthesis. To further understand the roles of these proteins in rubber formation, six different genes for latex abundant REF or SRPP proteins, including REF138,175,258 and SRPP117,204,243, were characterized from Hevea brasiliensis Reyan (RY 7-33-97. Sequence analysis showed that REFs have a variable and long N-terminal, whereas SRPPs have a variable and long C-terminal beyond the REF domain, and REF258 has a β subunit of ATPase in its N-terminal. Through two-dimensional electrophoresis (2-DE, each REF/SRPP protein was separated into multiple protein spots on 2-DE gels, indicating they have multiple protein species. The abundance of REF/SRPP proteins was compared between ethylene and control treatments or among rubber tree clones with different levels of latex productivity by analyzing 2-DE gels. The total abundance of each REF/SRPP protein decreased or changed a little upon ethylene stimulation, whereas the abundance of multiple protein species of the same REF/SRPP changed diversely. Among the three rubber tree clones, the abundance of the protein species also differed significantly. Especially, two protein species of REF175 or REF258 were ethylene-responsive only in the high latex productivity clone RY 8-79 instead of in RY 7-33-97 and PR 107. Some individual protein species were positively related to ethylene stimulation and latex productivity. These results suggested that the specific protein species could be more important than others for rubber production and post-translational modifications might play important roles in rubber biosynthesis.

FTIR spectra and mechanical strength analysis of some selected rubber derivatives

Science.gov (United States)

Gunasekaran, S.; Natarajan, R. K.; Kala, A.

2007-10-01

Rubber materials have wide range of commercial applications such as, infant diapers, famine hygiene products, drug delivery devices and incontinency products such as rubber tubes, tyres, etc. In the present work, studies on mechanical properties of some selected rubber materials viz., natural rubber (NR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR) and ethylene propylene diene monomer (EPDM) have been carried out in three states viz., raw, vulcanized and reinforced. To enhance the quality of rubber elastomers, an attempt is made to prepare new elastomers called polyblends. In the present study an attempt is made to blend NR with NBR and with EPDM. We here report, a novel approach for the evaluation of various physico-mechanical properties such as mechanical strength, tensile strength, elongation and hardness. The method is simple, direct and fast and involves infrared spectral measurements for the evaluation of these properties. With the applications of modern infrared spectroscopy, the mechanical strength of these rubber materials have been analyzed by calculating the internal standards among the methyl and methylene group vibrational frequencies obtained from FTIR spectroscopy. Also the tensile strength measurements carried out by universal testing machine. The results pertaining physico-mechanical properties of the rubber derivatives undertaken in the present study obtained by IR-based method are in good agreement with data resulted from the standard methods.

Study of the Properties of Polyurethane-waste Rubber Granulate Composites

Institute of Scientific and Technical Information of China (English)

W.W.Sulkowski; M.Moczy′ski; A.Sulkowska; A.Danch; J.Borek; S.Mistarz

2007-01-01

1 Results The production of rubber is very high and rises every year. Among other things it is directly connected with the growth of car production. Therefore, the processing of waste rubber and its management must be treated as a global problem. Used rubber may replace conventional fuel and, owing to its low price, can improve the economic effectiveness of combustion. Energy recovery by combustion of car tyres allows for rapid management of rubber waste. However, it is well-known that all kinds of wast...

Simplified High-Performance Roll Out Composite Magnetometer Boom, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In response to NASA's need for compact, low-cost deployable magnetometer booms for CubeSats, Roccor proposes to develop a Simple High-performance Roll-Out Composite...

Buffing dust as a filler of carboxylated butadiene-acrylonitrile rubber and butadiene-acrylonitrile rubber.

Science.gov (United States)

Chronska, K; Przepiorkowska, A

2008-03-01

Buffing dust from chrome tanned leather is one of the difficult tannery wastes to manage. It is also hazardous to both human health and the environment. The scientific literature rarely reports studies on dust management, especially on its utilization as a filler for elastomers. In this connection we have made an attempt to use this leather waste as a filler for rubbers such as XNBR and NBR. The addition of the buffing dust to rubber mixes brought improvement in mechanical properties, and increase in resistance to thermal ageing as well as in electric conductivity and crosslink density of vulcalizates.

Responses of rubber leaf phenology to climatic variations in Southwest China

Science.gov (United States)

Zhai, De-Li; Yu, Haiying; Chen, Si-Chong; Ranjitkar, Sailesh; Xu, Jianchu

2017-11-01

The phenology of rubber trees (Hevea brasiliensis) could be influenced by meteorological factors and exhibits significant changes under different geoclimates. In the sub-optimal environment in Xishuangbanna, rubber trees undergo lengthy periods of defoliation and refoliation. The timing of refoliation from budburst to leaf aging could be affected by powdery mildew disease (Oidium heveae), which negatively impacts seed and latex production. Rubber trees are most susceptible to powdery mildew disease at the copper and leaf changing stages. Understanding and predicting leaf phenology of rubber trees are helpful to develop effective means of controlling the disease. This research investigated the effect of several meteorological factors on different leaf phenological stages in a sub-optimal environment for rubber cultivation in Jinghong, Yunnan in Southwest China. Partial least square regression was used to quantify the relationship between meteorological factors and recorded rubber phenologies from 2003 to 2011. Minimum temperature in December was found to be the critical factor for the leaf phenology development of rubber trees. Comparing the delayed effects of minimum temperature, the maximum temperature, diurnal temperature range, and sunshine hours were found to advancing leaf phenologies. A comparatively lower minimum temperature in December would facilitate the advancing of leaf phenologies of rubber trees. Higher levels of precipitation in February delayed the light green and the entire process of leaf aging. Delayed leaf phenology was found to be related to severe rubber powdery mildew disease. These results were used to build predictive models that could be applied to early warning systems of rubber powdery mildew disease.

Passenger Spaceplanes and Airplanes that Have Variable Configuration for Sonic Boom Reduction

Directory of Open Access Journals (Sweden)

Constantin SANDU

2018-06-01

Full Text Available In the last time, the interest for passenger space plane, supersonic passenger aircraft and supersonic business jets is increasing. For reducing sonic boom effects at ground level, some companies proposed airplanes having fuselage with small traversal section or having curved fuselage. This paper presents a new practical method for exciting vibrations in the leading edge of wing, tail and airplane's nose surfaces in order to scatter the shock wave and to reduce the sonic boom impact at ground level. The leading edges of wing, tail and airplane nose are covered with thin elastic fairings made of carbon fiber composite material which are separated through small gaps by the adjacent surfaces of wing, tail and nose. When the aircraft flies over populated areas, compressed air bleed from the engine compressors excites the vibration of carbon fiber fairings. The air is released through calibrated nozzles and directly impinges on the fairing surface generating their vibration. Thus, the shock waves are scattered and the impact of sonic boom on ground is much reduced.

Recycling of Gamma Irradiated Inner Tubes in Butyl Based Rubber Compound

International Nuclear Information System (INIS)

Karaagac, B.

2006-01-01

Crosslinked elastomeric materials, such as tyres are of great challenge concerning the environmental and ecological reasons. Ionizing radiation seems to offer unique opportunities to tackle the problem of recycling of polymers and rubbers on account of its ability to cause chain scission and/or cross-linking of polymeric materials. There is only limited amount of work reported on the irradiation-induced degradation of rubbers. Unlike the majority of the elastomers with high levels of unsaturation, butyl rubber exhibits significant degradation by ionizing radiation action. In this study, recycling of gamma irradiated inner tubes made of butyl rubber in butyl based rubber compounds was studied. Used inner tubes were irradiated with gamma rays in air at 100 and 120 kGy absorbed doses. The compatibility of irradiated inner tubes with virgin butyl rubber was first investigated. Gamma irradiated inner tube wastes were replaced with butyl rubber up to 15 phr in the compound recipe. Similar recipes were also prepared by using the same quantity of commercial butyl rubber crumbs devulcanized by conventional methods. The rheological and mechanical properties and carbon black dispersion degree for both types of compounds prepared by using inner tubes scraps and commercial butyl crumbs were measured and were compared to the values of virgin butyl rubber compound. It is well known that mechanical properties are deteriorated when rubber crumb is added to the virgin compound. It was observed that the decrease in the mechanical properties was much lower for the compounds prepared from the tubes irradiated at 120 kGy than irradiated at 100 kGy. The better mechanical properties were obtained for the compounds prepared by recycling of irradiated inner tubes at 120 kGy than the compounds prepared by using commercial butyl crumbs. Almost similar carbon black distributions were observed for the all compounds studied. It has been concluded that gamma irradiated inner tubes are compatible

Method of Obtaining High Resolution Intrinsic Wire Boom Damping Parameters for Multi-Body Dynamics Simulations

Science.gov (United States)

Yew, Alvin G.; Chai, Dean J.; Olney, David J.

2010-01-01

The goal of NASA's Magnetospheric MultiScale (MMS) mission is to understand magnetic reconnection with sensor measurements from four spinning satellites flown in a tight tetrahedron formation. Four of the six electric field sensors on each satellite are located at the end of 60- meter wire booms to increase measurement sensitivity in the spin plane and to minimize motion coupling from perturbations on the main body. A propulsion burn however, might induce boom oscillations that could impact science measurements if oscillations do not damp to values on the order of 0.1 degree in a timely fashion. Large damping time constants could also adversely affect flight dynamics and attitude control performance. In this paper, we will discuss the implementation of a high resolution method for calculating the boom's intrinsic damping, which was used in multi-body dynamics simulations. In summary, experimental data was obtained with a scaled-down boom, which was suspended as a pendulum in vacuum. Optical techniques were designed to accurately measure the natural decay of angular position and subsequently, data processing algorithms resulted in excellent spatial and temporal resolutions. This method was repeated in a parametric study for various lengths, root tensions and vacuum levels. For all data sets, regression models for damping were applied, including: nonlinear viscous, frequency-independent hysteretic, coulomb and some combination of them. Our data analysis and dynamics models have shown that the intrinsic damping for the baseline boom is insufficient, thereby forcing project management to explore mitigation strategies.

Soil methane and CO2 fluxes in rainforest and rubber plantations

Science.gov (United States)

Lang, Rong; Blagodatsky, Sergey; Goldberg, Stefanie; Xu, Jianchu

2017-04-01

Expansion of rubber plantations in South-East Asia has been a land use transformation trend leading to losses of natural forest cover in the region. Besides impact on ecosystem carbon stocks, this conversion influences the dynamics of greenhouse gas fluxes from soil driven by microbial activity, which has been insufficiently studied. Aimed to understand how land use change affects the soil CO2 and CH4 fluxes, we measured surface gas fluxes, gas concentration gradient, and 13C signature in CH4 and soil organic matter in profiles in a transect in Xishuangbanna, including a rainforest site and three rubber plantation sites with age gradient. Gas fluxes were measured by static chamber method and open chamber respiration system. Soil gases were sampled from installed gas samplers at 5, 10, 30, and 75cm depth at representative time in dry and rainy season. The soil CO2 flux was comparable in rainforest and old rubber plantations, while young rubber plantation had the lowest rate. Total carbon content in the surface soil well explained the difference of soil CO2 flux between sites. All sites were CH4 sinks in dry season and uptake decreased in the order of rainforest, old rubber plantations and young rubber plantation. From dry season to rainy season, CH4 consumption decreased with increasing CH4 concentration in the soil profile at all depths. The enrichment of methane by 13CH4 shifted towards to lowerδ13C, being the evidence of enhanced CH4 production process while net surface methane flux reflected the consumption in wet condition. Increment of CH4 concentration in the profile from dry to rainy season was higher in old rubber plantation compared to rainforest, while the shifting of δ13CH4 was larger in rainforest than rubber sites. Turnover rates of soil CO2 and CH4 suggested that the 0-5 cm surface soil was the most active layer for gaseous carbon exchange. δ13C in soil organic matter and soil moisture increased from rainforest, young rubber plantation to old

A study of sonic boom overpressure trends with respect to weight, altitude, Mach number, and vehicle shaping

Science.gov (United States)

Needleman, Kathy E.; Mack, Robert J.

1990-01-01

This paper presents and discusses trends in nose shock overpressure generated by two conceptual Mach 2.0 configurations. One configuration was designed for high aerodynamic efficiency, while the other was designed to produce a low boom, shaped-overpressure signature. Aerodynamic lift, sonic boom minimization, and Mach-sliced/area-rule codes were used to analyze and compute the sonic boom characteristics of both configurations with respect to cruise Mach number, weight, and altitude. The influence of these parameters on the overpressure and the overpressure trends are discussed and conclusions are given.

Liquefaction of ground tire rubber at low temperature.

Science.gov (United States)

Cheng, Xiangyun; Song, Pan; Zhao, Xinyu; Peng, Zonglin; Wang, Shifeng

2018-01-01

Low-temperature liquefaction has been investigated as a novel method for recycling ground tire rubber (GTR) into liquid using an environmentally benign process. The liquefaction was carried out at different temperatures (140, 160 and 180 °C) over variable time ranges (2-24 h) by blending the GTR with aromatic oil in a range from 0 to 100 parts per hundred rubber (phr). The liquefied GTR was separated into sol (the soluble fraction of rubber which can be extracted with toluene) and gel fractions (the solid fraction obtained after extraction) to evaluate the reclaiming efficiency. It was discovered that the percentage of the sol fraction increased with time, swelling ratio and temperature. Liquefied rubber was obtained with a high sol fraction (68.34 wt%) at 140 °C. Simultaneously, separation of nano-sized carbon black from the rubber networks occurred. The separation of carbon black from the network is the result of significant damage to the cross-linked-network that occurs throughout the liquefaction process. During liquefaction, a competitive reaction between main chain scission and cross-link bond breakage takes place. Copyright © 2017 Elsevier Ltd. All rights reserved.

Properties of concrete containing scrap-tire rubber--an overview.

Science.gov (United States)

Siddique, Rafat; Naik, Tarun R

2004-01-01

Solid waste management is one of the major environmental concerns in the United States. Over 5 billion tons of non-hazardous solid waste materials are generated in USA each year. Of these, more than 270 million scrap-tires (approximately 3.6 million tons) are generated each year. In addition to this, about 300 million scrap-tires have been stockpiled. Several studies have been carried out to reuse scrap-tires in a variety of rubber and plastic products, incineration for production of electricity, or as fuel for cement kilns, as well as in asphalt concrete. Studies show that workable rubberized concrete mixtures can be made with scrap-tire rubber. This paper presents an overview of some of the research published regarding the use of scrap-tires in portland cement concrete. The benefits of using magnesium oxychloride cement as a binder for rubberized concrete mixtures are also presented. The paper details the likely uses of rubberized concrete.

3D silicone rubber interfaces for individually tailored implants.

Science.gov (United States)

Stieghorst, Jan; Bondarenkova, Alexandra; Burblies, Niklas; Behrens, Peter; Doll, Theodor

2015-01-01

For the fabrication of customized silicone rubber based implants, e.g. cochlear implants or electrocortical grid arrays, it is required to develop high speed curing systems, which vulcanize the silicone rubber before it runs due to a heating related viscosity drop. Therefore, we present an infrared radiation based cross-linking approach for the 3D-printing of silicone rubber bulk and carbon nanotube based silicone rubber electrode materials. Composite materials were cured in less than 120 s and material interfaces were evaluated with scanning electron microscopy. Furthermore, curing related changes in the mechanical and cell-biological behaviour were investigated with tensile and WST-1 cell biocompatibility tests. The infrared absorption properties of the silicone rubber materials were analysed with fourier transform infrared spectroscopy in transmission and attenuated total reflection mode. The heat flux was calculated by using the FTIR data, emissivity data from the infrared source manufacturer and the geometrical view factor of the system.

Degrading radiation effects on properties of bromobutyl rubber compounds

Energy Technology Data Exchange (ETDEWEB)

Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Pozenato, Cristina A.; Lugao, Ademar B., E-mail: srscagliusi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

The understanding of chemistry involved in degradation induced radiation is becoming more and more relevant in the re-use of polymeric materials, as well in beneficial radiation uses. Degrading radiation effects have been considered from viewpoint of controlled degradation for isoprene/isobutene in rubbers for recycling purposes. Bromobutyl rubber (BIIR) is an isobutylene/isoprene copolymer comprising 1.9 to 2.1% bromine and has a lot of applications including in tires air-chambers. In this work there were evaluated gamma-irradiation effects for re-use or recycling objectives in elastomeric bromobutyl compositions irradiated at 5, 15, 25, 50, 100,150 and 200 kGy. Mechanical properties, hardness and swelling were assessed in non-vulcanized and vulcanized rubber, non-irradiated and irradiated at different doses. The major gamma radiation effect in butyl rubber is the generation of free radicals along changes in mechanical properties. Irradiation effects in bromobutyl rubber compounds were comprehensively investigated, demonstrated and discussed. (author)

Degrading radiation effects on properties of bromobutyl rubber compounds

International Nuclear Information System (INIS)

Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Pozenato, Cristina A.; Lugao, Ademar B.

2013-01-01

The understanding of chemistry involved in degradation induced radiation is becoming more and more relevant in the re-use of polymeric materials, as well in beneficial radiation uses. Degrading radiation effects have been considered from viewpoint of controlled degradation for isoprene/isobutene in rubbers for recycling purposes. Bromobutyl rubber (BIIR) is an isobutylene/isoprene copolymer comprising 1.9 to 2.1% bromine and has a lot of applications including in tires air-chambers. In this work there were evaluated gamma-irradiation effects for re-use or recycling objectives in elastomeric bromobutyl compositions irradiated at 5, 15, 25, 50, 100,150 and 200 kGy. Mechanical properties, hardness and swelling were assessed in non-vulcanized and vulcanized rubber, non-irradiated and irradiated at different doses. The major gamma radiation effect in butyl rubber is the generation of free radicals along changes in mechanical properties. Irradiation effects in bromobutyl rubber compounds were comprehensively investigated, demonstrated and discussed. (author)

HERBERT HOOVER, GREAT BRITAIN, AND THE RUBBER CRISIS, 1923-1926

Directory of Open Access Journals (Sweden)

Silvano A. Wueschner

2000-01-01

Full Text Available This paper examines the controversy arising out of Great Britain’s decision to implement the Stevenson plan. It examines, in particular, the role played by Herbert Hoover, both behind the scenes and in an effort to affect the repeal of the Stevenson scheme and at the same time to encourage and support the development of new sources of rubber under the control of American producers. During the period 1920-1922 rubber producing countries were confronted by the specter of overproduction. The existence of even a short term oversupply coupled with the business slump, a reaction from the war, led to a decline in the price of rubber. British producers succeeded in inducing the British Colonial authorities to support a scheme whereby rubber exports would be regulated in order to bring about an increase in the price of rubber. This plan, developed by the Stevenson Committee, called for a small minimum tax on all exports. Moreover, it soughtto limit production by establishing a quota based on the actual production of rubber during the 1919-1920 growing season. A progressive tax was applied to exports beyond standard production. American reaction to the scheme was varied. Secretary of Commerce Hoover, while publicly stating that the price of rubber had been low and was supportive of efforts to regulate production, behind the scenes showed a great deal of concern about the actions of the British government in regulating a commodity of which the United States was the single largest consumer. He was also linked, by some, to the idea that Great Britain sought to pay its war debt to the United States through the application of this tax. Much was made in American newspapers and the British press about Hoover’s criticism of British rubber restrictions. He was not opposed to regulating the supply of rubber, but only to the involvement of a government in the process, especially when it affected American producers and consumers. In response he proposed a scheme

STUDY ON HEAT DYNAMIC LOADING OF RUBBER

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T. I. Igumenova

2015-01-01

Full Text Available A number of studies on heat buildup in tire rubber surface scan method samples using a thermal imaging camera. Investigated the exothermic chemical reaction mechanical destruction rubber when loading designs permanent cyclic stretching with deformation of the working zone 50%. Percentage of deformation of the working zone was chosen on the basis of the actual data on the stretch-compression zone "Rusk" tires, which is the maximum level difference of deformation during run-in. Experiment plan provided for periodic relaxation samples of at least 72 hours for more accurate simulation of operation process of structural products. Created and processed data on temperature changes in samples for bar and line profile for rubber compounds with the introduction of nanomodifiers (fulleren technical carbon in comparison with the control sample without him. The data obtained reflect the nature of heat depending on the composition of the compound. Identified common patterns of thermal nature of physico-chemical process mechanical destruction rubbers. For rubber with nanomodifikatorom there has been an increase in the temperature interval reaction from a minimum to a maximum 2 degrees that is also linked to the rise in the average temperature of the reaction on the histogram also at 2-3 degrees of deformation under the same conditions and the level of cyclic loading. However, the temperature in the control sample that is associated with the beginning of the formation of hardened rubber structures, economies of Mallinz-Petrikeev, occurs with delay twice compared with modified Fullerenes. Measurement of physic-mechanical indicators selected in the course of testing of samples showed the beginning of formation of structure with increased strength of samples in the sample temperature zone that corresponds to the thermal effect of èndotermičeskomu recombination reactions of macromolecules.

Mechanical Properties of Graphene-Rubber Nanocomposites

Science.gov (United States)

Anhar, N. A. M.; Ramli, M. M.; Hambali, N. A. M. A.; Aziz, A. A.; Mat Isa, S. S.; Danial, N. S.; Abdullah, M. M. A. B.

2017-11-01

This research focused on development of wearable sensor device by using Prevulcanized Natural Rubber (PV) and Epoxidized Natural Rubber (ENR 50) latex incorporated with graphene oxide (GO), graphene paste, graphene powder and reduced graphene oxide (rGO) powder. The compounding formulation and calculation were based on phr (parts per hundred rubber) and all the samples were then tested for mechanical properties using Instron 5565 machine. It was found that the sonication effects on tensile strength may have better quality of tensile strength compared to non-sonicated GO. For PV incorporate GO, the optimum loading was best determined at loading 1.5 phr with or without sonication and similar result was recorded for PV/G. For ENR 50 incorporate graphene paste and rGO powder nanocomposite shows the best optimum was at 3.0 phr with 24 hours’ sonication.

Chemi-microbial processing of waste tire rubber: A project overview

International Nuclear Information System (INIS)

Romine, R.A.; Snowden-Swan, L.

1993-12-01

PNL is developing a method to use thiophillic microorganisms to devulcanize (biodesulfurize) the surface of ground rubber particles, which will improve the bonding and adhesion of the ground tire rubber into the virgin tire rubber matrix. The Chemi-microbial processing approach, introduced in this paper, is targeted at alleviating the waste tire problem in an environmentally conscious manner; it may also be applied to improve asphaltic materials and rubber and polymeric wastes to facilite their recycling. This paper outlines the logic and technical methods that will be used

Utilization of waste tire rubber in manufacture of oriented strandboard.

Science.gov (United States)

Ayrilmis, Nadir; Buyuksari, Umit; Avci, Erkan

2009-09-01

Some physical and mechanical properties of oriented strandboards (OSBs) containing waste tire rubber at various addition levels based on the oven-dry strand weight, using the same method as that used in the manufacture of OSB. Two resin types, phenol-formaldehyde (PF) and polyisocyanate, were used in the experiments. The manufacturing parameters were: a specific gravity of 0.65 and waste tire rubber content (10/90, 20/80 and 30/70 by wt.% of waste tire rubber/wood strand). Average internal bond values of PF-bonded OSB panels with rubber chips were between 17.6% and 48.5% lower than the average of the control samples while polyisocyanate bonded OSBs were 16.5-50.6%. However, water resistance and mechanical properties of OSBs made using polyisocyanate resin were found to comply with general-purpose OSB minimum property requirements of EN 300 Type 1 (1997) values for use in dry conditions at the lowest tire rubber loading level (10%) based on the oven-dry panel weight. The tire rubber improved water resistance of the OSB panel due to its almost hydrophobic property. Based on the findings obtained from this study, we concluded that waste tire rubber could be used for general-purpose OSB manufacturing up to 10% ratio based on the oven-dry panel weight.

their use as Accelerator in Curing Process of Rubber Compounds

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S. taghvaee

2007-06-01

Full Text Available In some special cases, rubber compounds with high amounts of unsaturated elastomer are recommended with organic sulfur donors instead of mineral sulfurs. In this condition, activated sulfur is produced in situ and curingprocess is facilitated without accelerators. Organic sulfur donor compounds have low thermal stability and in the vulcanization temperature produce free and activated sulfurs. The advantages of these compounds are:1. High effectiveness of curing agent in low quantities in rubber compounds manufacturing.2. Producing activated sulfurs in controlled condition and avoiding the over curing of rubber compounds.In this report the novel synthesis of some derivatives of diamino-disulfides which can be applied as sulfur donors in vulcanization of special rubber compounds is introduced. The key process is reaction of sulfurmonochloride with amines in petroleum ether as solvent in low temperature. Dithio-dimorpholine(DTDM, dithio-dipipyridyl (DTDP, dithio-bis dibutylamine (DTBDB and dithio-bisdiisopropyl amine (DTBDI were prepared according to this method. All products thus obtained were characterized by 1H and 13C-NMR spectroscopies. The effects of accelerating and sulfur donoring of all prepared agents were detected in rubber compounds with natural and synthetic rubber bases. All physical, chemical, reological and mechanical properties of rubber compounds based on prepared sulfur donors were characterized.

The optimum content of rubber ash in concrete: flexural strength

Science.gov (United States)

Senin, M. S.; Shahidan, S.; Shamsuddin, S. M.; Ariffin, S. F. A.; Othman, N. H.; Rahman, R.; Khalid, F. S.; Nazri, F. M.

2017-11-01

Discarded scrap tyres have become one of the major environmental problems nowadays. Several studies have been carried out to reuse waste tires as an additive or sand replacement in concrete with appropriate percentages of tire rubber, called as rubberized concrete to solve this problem. The main objectives of this study are to investigate the flexural strength performance of concrete when adding the rubber ash and also to analyse the optimum content of rubber ash in concrete prisms. The performance total of 30 number of concrete prisms in size of 100mm x 100mm x 500 mm were investigated, by partially replacement of rubber ash with percentage of 0%, 3%, 5%, 7% and 9% from the volume of the sand. The flexural strength is increased when percentage of rubber ash is added 3% from control concrete prism, RA 0 for both concrete prism age, 7 days and 28 days with value 1.21% and 0.976% respectively. However, for RA 5, RA 7 and RA 9, the flexural strength was decreased compared to the control for both age, 7 days and 28 days. In conclusion, 3% is the optimum content of rubber ash in concrete prism for both concrete age

Synthesis, characterization and degradation behavior of admicelled polyacrylate-natural rubber

International Nuclear Information System (INIS)

Pongpilaipruet, Angkana; Magaraphan, Rathanawan

2015-01-01

In order to improve weatherability of the cured natural rubber, the novel introduction of good ozone resistant polymers such as polyacrylates (poly(methyl acrylate) (PMA) or poly(methyl methacrylate) (PMMA)) into natural rubber (NR) by admicellar polymerization was investigated in this work. The admicellar polymerization to synthesize polyacrylate layer over the surface of NR latex particles was performed with varying monomer type (PMA and PMMA) and content (50 and 100 mM). The admicelled PMMA showed higher molecular weight than PMA. Fourier transform infrared spectra of the admicellar synthesized natural rubbers exhibited characteristic peaks of those polyacrylates. Micrographs from transmission electron and field emission scanning electron microscopes (FE-SEM) revealed the coatings of PMA and PMMA over the rubber particles, suggesting a core-shell structure. Thermogravimetric analysis revealed that the admicelled rubbers not only showed an improvement in heat stability but also a single decomposition temperature. After vulcanization, FE-SEM results showed the cured admicelled rubbers had phase transformation from core-shell to phase separation (aggregate domains of polyacrylate-rich phase) with smooth interface. This agreed well to their one glass transition temperature (∼−48 °C) which indicated good miscibility between NR and each polyacrylate. The cracks generated after exposure to ozone found in the admicelled rubbers were smaller than those in NR, suggesting better ozone resistance was achieved. Increasing monomer concentration led to less cracks or much better ozone resistance. Furthermore, changes in mechanical properties after ozone exposure of the admicelled PMA-NR were less than those of the admicelled PMMA-NR (having the same shell content) and the NR, respectively. - Highlights: • We use admicellar technique to add polyacrylates to NR in form of core-shell rubber. • This core-shell structure was physically formed as seen by the phase

Synthesis, characterization and degradation behavior of admicelled polyacrylate-natural rubber

Energy Technology Data Exchange (ETDEWEB)

Pongpilaipruet, Angkana; Magaraphan, Rathanawan, E-mail: rathanawan.k@chula.ac.th

2015-06-15

In order to improve weatherability of the cured natural rubber, the novel introduction of good ozone resistant polymers such as polyacrylates (poly(methyl acrylate) (PMA) or poly(methyl methacrylate) (PMMA)) into natural rubber (NR) by admicellar polymerization was investigated in this work. The admicellar polymerization to synthesize polyacrylate layer over the surface of NR latex particles was performed with varying monomer type (PMA and PMMA) and content (50 and 100 mM). The admicelled PMMA showed higher molecular weight than PMA. Fourier transform infrared spectra of the admicellar synthesized natural rubbers exhibited characteristic peaks of those polyacrylates. Micrographs from transmission electron and field emission scanning electron microscopes (FE-SEM) revealed the coatings of PMA and PMMA over the rubber particles, suggesting a core-shell structure. Thermogravimetric analysis revealed that the admicelled rubbers not only showed an improvement in heat stability but also a single decomposition temperature. After vulcanization, FE-SEM results showed the cured admicelled rubbers had phase transformation from core-shell to phase separation (aggregate domains of polyacrylate-rich phase) with smooth interface. This agreed well to their one glass transition temperature (∼−48 °C) which indicated good miscibility between NR and each polyacrylate. The cracks generated after exposure to ozone found in the admicelled rubbers were smaller than those in NR, suggesting better ozone resistance was achieved. Increasing monomer concentration led to less cracks or much better ozone resistance. Furthermore, changes in mechanical properties after ozone exposure of the admicelled PMA-NR were less than those of the admicelled PMMA-NR (having the same shell content) and the NR, respectively. - Highlights: • We use admicellar technique to add polyacrylates to NR in form of core-shell rubber. • This core-shell structure was physically formed as seen by the phase

The Control of Welding Deformation of the Three-Section Arm of Placing Boom of HB48B Pump Truck

Science.gov (United States)

Wang, Zhi-ling

2018-02-01

The concrete pump truck is the construction equipment of conveying concrete with self contained base plate and distributing boom. It integrates the pump transport mechanism of the concrete pump, and the hydraulic roll-folding type distributing boom used to distribute materials, and the supporting mechanism into the automobile chassis, and it is the concrete conveying equipment with high efficient and the functions of driving, pumping, and distributing materials. The placing boom of the concrete pump truck is the main force member in the pump parts with bearing great pressure, and its stress condition is complex. Taking the HB48B placing boom as an example, this paper analyzes and studies the deformation produced by placing boom of pump truck, and then obtains some main factors affecting the welding deformation. Through the riveter “joint” size, we controlled the process parameters, post-welding processing, and other aspects. These measures had some practical significance to prevent, control, and reduce the deformation of welding.

Model fire tests on polyphosphazene rubber and polyvinyl chloride (PVC)/nitrile rubber foams

Science.gov (United States)

Widenor, W. M.

1978-01-01

A video tape record of model room fire tests was shown, comparing polyphosphazene (P-N) rubber and polyvinyl chloride (PVC)/nitrile rubber closed-cell foams as interior finish thermal insulation under conditions directly translatable to an actual fire situation. Flashover did not occur with the P-N foam and only moderate amounts of low density smoke were formed, whereas with the PVC/nitrile foam, flashover occurred quickly and large volumes of high density smoke were emitted. The P-N foam was produced in a pilot plant under carefully controlled conditions. The PVC/nitrile foam was a commercial product. A major phase of the overall program involved fire tests on P-N open-cell foam cushioning.

El Frente Popular: Representaciones sobre la ciudadanía en Chile, 1930-1950

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Bárbara Silva

2017-05-01

Full Text Available The Frente Popular: Representations of Citizenship in Chile, 1930-1950This article seeks to characterize the representations of citizenship as promoted by the political actors of the Frente Popular (Popular Front, a centre-left coalition of parties in Chile around 1940. Citizenship was understood as being a combination of discourses and practices that formed a complex balance which enabled the continuance of those representations far into the twentieth century, despite the Frente Popular’s short existence. We identify and define the main characteristics of this citizenship as a voter citizen, a learning citizenry, a fulfilled citizenry, and a consumer citizen. Our premise is that, in contrast to projects of contemporary ‘populist fronts’, these representations were able to materialize in institutional practices that were visible in the public space. This allowed for the consolidation of the political project of the Frente Popular beyond its termination as a coalition in 1941 up to the end of the national leadership of the Partido Radical in 1952.ResumenEl objetivo de este artículo es caracterizar las representaciones de la ciudadanía promovidas por los actores que formaron parte del Frente Popular, una alianza política de centro izquierda en el Chile en torno a 1940. La ciudadanía se comprendió como una suma de discursos y prácticas que formaron un complejo equilibrio que permitió, a pesar de su breve duración, la permanencia de esas representaciones a lo largo del siglo XX. Las principales características que identificamos de esa ciudadanía fueron la definición de un ciudadano elector; una ciudadanía que se educa; una ciudadanía redimida y un ciudadano consumidor. El argumento que se propone es que, a diferencia de otros proyectos ‘frentepopulistas’ contemporáneos, estas representaciones pudieron materializarse en prácticas institucionales visibles en el espacio público. Ello permitió consolidar el proyecto pol

Mechanical properties of concrete containing a high volume of tire-rubber particles.

Science.gov (United States)

Khaloo, Ali R; Dehestani, M; Rahmatabadi, P

2008-12-01

Due to the increasingly serious environmental problems presented by waste tires, the feasibility of using elastic and flexible tire-rubber particles as aggregate in concrete is investigated in this study. Tire-rubber particles composed of tire chips, crumb rubber, and a combination of tire chips and crumb rubber, were used to replace mineral aggregates in concrete. These particles were used to replace 12.5%, 25%, 37.5%, and 50% of the total mineral aggregate's volume in concrete. Cylindrical shape concrete specimens 15 cm in diameter and 30 cm in height were fabricated and cured. The fresh rubberized concrete exhibited lower unit weight and acceptable workability compared to plain concrete. The results of a uniaxial compressive strain control test conducted on hardened concrete specimens indicate large reductions in the strength and tangential modulus of elasticity. A significant decrease in the brittle behavior of concrete with increasing rubber content is also demonstrated using nonlinearity indices. The maximum toughness index, indicating the post failure strength of concrete, occurs in concretes with 25% rubber content. Unlike plain concrete, the failure state in rubberized concrete occurs gently and uniformly, and does not cause any separation in the specimen. Crack width and its propagation velocity in rubberized concrete are lower than those of plain concrete. Ultrasonic analysis reveals large reductions in the ultrasonic modulus and high sound absorption for tire-rubber concrete.

Radiation vulcanization of natural rubber latex sensitized with commercial gases

International Nuclear Information System (INIS)

Chirinos, H.; Lugao, A.

2002-01-01

The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

Radiation vulcanization of natural rubber latex sensitized with commercial gases

Energy Technology Data Exchange (ETDEWEB)

Chirinos, H.; Lugao, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

2002-07-01

The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

Radionuclide solubilities in boom clay. Final report, part 2 : a report produced for ONDRAF/NIRAS

International Nuclear Information System (INIS)

Baker, S.; Baston, G.M.N.; Boult, K.A.

2000-01-01

The release of radionuclides from a High Level Radioactive Waste repository situated in the Boom Clay at Mol would depend, in part, on their retardation within the Boom Clay. A number of parameters are required to assess such retardation; these include the solubilities of key radionuclides and their sorption behaviour. ONDRAF/NIRAS has identified neptunium, technetium, selenium, uranium and plutonium as elements for study. AEA Technology plc was requested to undertake a joint experimental and modelling study to determine the solubilities of these five elements under conditions representative of those in the Boom Clay (the in situ chemical conditions are pH∼8, Eh ∼ -230 mV). The work programme was carried out over three years, and for completeness this final report includes all the results

Ultraviolet curing of acrylated liquid natural rubber for surface coating application

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Kannikar Kwanming

2009-01-01

Full Text Available Ultraviolet curable acrylated liquid natural rubber was prepared by grafting of photosensitive molecule onto liquid natural rubber for surface coating application. The liquid natural rubber (LNR was firstly obtained by degradation of natural rubber latex with hydrogen peroxide and cobalt acetylacetonate at 65oC for 72 hrs. The preparation of acrylated natural rubber was carried out by the reaction of acrylic acid and epoxidized liquid natural rubber (ELNR prior obtained from LNR with formic acid and hydrogen peroxide in the ratio of 2:1 by weight in toluene at 80oC for 6, 9, 12, 18, and 24 hrs. It was found that the percentage of acrylate grafted onto liquid natural rubber depended on the reaction time. Surface coating was performed by using acrylated liquid natural rubber and 1,6-hexanediol diacrylate (HDDA or tripropylene glycol diacrylate (TPGDA as a crosslinker and Irgarcure 184 or Irgarcure 651 as a photoinitiator under UV exposure for 30, 60, and 90 seconds. The hardness test of cured products was investigated using the Pencil hardness test at pencil level of 2B to 6H. It was found that the highest hardness of surface coating was at pencil level of 4H for the product using TPGDA and Irgacure 651 in the ratio of 80:10 parts per hundred of rubber (phr. The cured products were able to resist to 2% H2SO4 and distilled water for more than 24 hrs.

Experimental Investigation on Damping Property of Coarse Aggregate Replaced Rubber Concrete

Science.gov (United States)

Sugapriya, P.; Ramkrishnan, R.; Keerthana, G.; Saravanamurugan, S.

2018-02-01

Rubber has good damping and vibrational characteristics and can reduce cracking significantly due to its elastic nature. This property of rubber can be incorporated in concrete to control vibrations and create better pavements. Crumb Rubber on being dumped in landfills has serious repercussions and causes soil and land pollution. An innovative use of waste tires is shredding them into small pieces and using them as a replacement for coarse aggregate. Crumb rubber is obtained by chopping scrap tires, and in this study it was added in two different sets named SET 1 - Treated Crumb Rubber and concrete, and SET 2 - Treated Crumb rubber with Ultra Fine GGBS as admixture in concrete. Coarse aggregate replaces Rubber in each of the 2 SET’s in proportions of 5, 10, 15 and 20%. Properties like Compressive Strength, Young’s Modulus, Direct and Semi direct Ultrasonic Pulse Velocity, Sorptivity, Damping ratio and Frequency were found out. Deformation and mode shape were studied with modal analysis and static analysis by applying a uniform pressure corresponding to the highest compressive strength of the slab, using ANSYS.

Laboratory Evaluation of Ground Tire Rubber in Stone Mastic Asphalt

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R. Muniandy

2004-12-01

Full Text Available Stone mastic asphalt (SMA is a gap-graded mix whereby stiffer asphalt cement is required to bind the stone matrix or arrangement of stones together. Although various asphalt additives are traditionally available, the use of rubber crumbs in SMA is still a new rresearch endeavor. Many countries around the world are facing serious problems on what to do with reject or discarded tires. In the present study, commercial truck tires, containing 70% natural rubber, were ground and pre-blended in 80-100 penetration asphalt for use in SMA mixtures. An assessment was made of the laboratory performance of rubberized SMA in terms of stability, resilent modulus, dynamic creep and tensile strength ratio. It was observed that the performance of SMA with ground tire rubber was for superior as compared to SMA mix with unmodified asphalt. Sulfur and Styrene Butadeline Rubber (SBR were used in rubberized SMA mixes as additives to test the sensitivity of SMA mixtures. As standard practice a 0.3% newly developed cellulose oil palm fiber was used in SMA to minimize the asphalt drain-down effects.

Improved properties of dissimilar rubber-rubber blends using plasma polymer encapsulated curatives : a novel surface modification method to improve co-vulcanization

NARCIS (Netherlands)

Guo, R.

2009-01-01

In industrial applications, different rubber types are often blended to fine-tune or optimize the property portfolio required for successful performance of articles. Considering the complexity of a rubber blend compound, wherein numerous additives are involved, vulcanization or cure mismatch often

Strength and microstructure characteristics of the recycled rubber tire-sand mixtures as lightweight backfill.

Science.gov (United States)

Zhang, Tao; Cai, Guojun; Duan, Weihong

2018-02-01

The disposal of scrap rubber tires has induced critical environmental issue worldwide due to the rapid increase in the number of vehicles. Recycled scrap tires as a construction material in civil engineering have significant environmental benefits from a waste management perspective. A systematic study that deals with strength and microstructure characteristics of the rubber-sand mixtures is initiated, and mechanical response of the mixtures is discussed in this investigation. Experiments were conducted to evaluate the effects of rubber fraction on the basic properties including mass density (ρ), stress-strain characteristics, shear strength, and unconfined compression strength (q u ) of the rubber-sand mixtures. Additionally, scanning electron microscopy (SEM) was carried out to reveal the microstructure characteristics of the mixtures with various rubber fractions. A discussion on the micromechanics of the mixtures also was conducted. This study demonstrates that the ρ, friction angle, and q u decrease linearly with an increase in rubber fraction, whereas shear strain at peak increases. The stress-strain characteristics of the rubber-sand mixtures shift from brittle to ductile as the rubber fraction increase. These changes are attributed to remarkably lower stiffness and higher compressibility of the rubber particle compared with those of the conventional mineral aggregates. With an increase in the rubber fraction, the mechanical response of rubber-sand mixtures exhibits two types: sand-like material and rubber-like material. Rubber particle possesses the capacity to prevent the contacted sand particles from sliding at lower rubber fraction, whereas it transmits the applied loadings as the rubber fraction increased. This outcome reinforces the practicability of using recycled rubber tire-sand mixtures as a lightweight backfill in subbase/base applications.

A review on fatigue life prediction methods for anti-vibration rubber materials

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Xiaoli WANG

2016-08-01

Full Text Available Anti-vibration rubber, because of its superior elasticity, plasticity, waterproof and trapping characteristics, is widely used in the automotive industry, national defense, construction and other fields. The theory and technology of predicting fatigue life is of great significance to improve the durability design and manufacturing of anti-vibration rubber products. According to the characteristics of the anti-vibration rubber products in service, the technical difficulties for analyzing fatigue properties of anti-vibration rubber materials are pointed out. The research progress of the fatigue properties of rubber materials is reviewed from three angles including methods of fatigue crack initiation, fatigue crack propagation and fatigue damage accumulation. It is put forward that some nonlinear characteristics of rubber under fatigue loading, including the Mullins effect, permanent deformation and cyclic stress softening, should be considered in the further study of rubber materials. Meanwhile, it is indicated that the fatigue damage accumulation method based on continuum damage mechanics might be more appropriate to solve fatigue damage and life prediction problems for complex rubber materials and structures under fatigue loading.

Time series analysis of the behavior of brazilian natural rubber

Directory of Open Access Journals (Sweden)

Antônio Donizette de Oliveira

2009-03-01

Full Text Available The natural rubber is a non-wood product obtained of the coagulation of some lattices of forest species, being Hevea brasiliensis the main one. Native from the Amazon Region, this species was already known by the Indians before the discovery of America. The natural rubber became a product globally valued due to its multiple applications in the economy, being its almost perfect substitute the synthetic rubber derived from the petroleum. Similarly to what happens with other countless products the forecast of future prices of the natural rubber has been object of many studies. The use of models of forecast of univariate timeseries stands out as the more accurate and useful to reduce the uncertainty in the economic decision making process. This studyanalyzed the historical series of prices of the Brazilian natural rubber (R$/kg, in the Jan/99 - Jun/2006 period, in order tocharacterize the rubber price behavior in the domestic market; estimated a model for the time series of monthly natural rubberprices; and foresaw the domestic prices of the natural rubber, in the Jul/2006 - Jun/2007 period, based on the estimated models.The studied models were the ones belonging to the ARIMA family. The main results were: the domestic market of the natural rubberis expanding due to the growth of the world economy; among the adjusted models, the ARIMA (1,1,1 model provided the bestadjustment of the time series of prices of the natural rubber (R$/kg; the prognosis accomplished for the series supplied statistically adequate fittings.

Application of gamma irradiation for incorporation of rubber powder in the formulations

International Nuclear Information System (INIS)

Kiyan, Ludmila Y.P.; Lugao, Ademar B.; Parra, Duclerc F.; Zaharescu, Traian

2013-01-01

The aim of this paper was to study the behavior of rubber recycle, in powder form of rubber industry. It was used EPDM rubber powder. The rubber powder was irradiated and used directly in classical formulations of rubber vulcanizate. The master-batch processed material was irradiated at doses of 50, 100 and 150kGy in 60 Co source at 5kGy s -1 rate, at room temperature. Gamma radiation created active sites devulcanization for further integration of the material (rubber powder) with facilities in formulations of commercial use. The processes were compared and their products were characterized by analytical methods of the physical properties such as tensile strength, elongation, hardness, rheology and abrasion tests. (author)

Preparation of Natural Rubber (NR) Based Nano-Sized Materials Using Sol-Gel Technique

International Nuclear Information System (INIS)

Dahlan Mohd; Mahathir Mohamed

2011-01-01

The objectives of this project are to prepare nano-sized natural rubber-based hybrid coating material by sol-gel technique; to explore the possibility of producing ENR-Si (epoxidized natural rubber-silica) cramer with toughening effects; and to use it in radiation curing of surface coating. Since early 1960s Malaysia has introduced various forms of value-added natural rubber such as Standard Malaysian Rubber (SMR), methylmethacrylate-grafted natural rubber (MG rubber), followed by liquid natural rubber and epoxidized natural rubber (ENR). Products such as liquid epoxidized natural rubber acrylate (LENRA) and thermoplastic natural rubber (TPNR) are still on-going research projects in Nuclear Malaysia. The former has strong possibility to be used as radiation-sensitive comparabilities in TPNR blends, besides its original purpose for example in radiation curing of surface coating. But earlier findings indicated that, to make it (as for surface coating) more effective, reinforcement system is needed to be introduced. Strong candidate is silica by sol-gel technique, since common reinforcement filler for example carbon black has drawbacks in this particular case. This technique was introduced in late 1960s to produce metal oxides such as silica and titanium oxides in solution. (author)

The use of radiotracers in natural rubber research in Malaysia

International Nuclear Information System (INIS)

Lai, P.F.; Singh, M.M.

1981-01-01

Five main areas where radiotracers have been used in research on natural rubber are on studies on the uptake of plant nutrients by Hevea brasiliensis using 32 P, 86 Rb and 45 Ca as tracers; biosynthesis of Hevea rubber using 14 C or 3 H labelled intermediates; translocation and metabolism of 14 C. Ethephon in Hevea brasiliensis; use of radiotracers as analytical tools and adsorption of labelled fatty acid soaps on natural rubber lattices. These studies are discussed to show the powerful tool that radiotracers provide in agricultural, biochemical and chemical research on natural rubber. (author)

Competitiveness and Exports Sustainability of the Indonesian Natural Rubber

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Rumbiati Kamaludin

2018-03-01

Full Text Available This paper examines Indonesian competitiveness in export of natural rubber commodities by employing set of revealed comparative advantage (RCA and Export competitive index (ECI with respect to global trade. The market structure that is formed on natural rubber commodities is calculated using Herfindahl Index and Concentration Ratio analysis tools shows the oligopoly-shaped market structure. Calculation of comparative advantage with RCA analysis shows that the four countries exporting natural rubber, namely Thailand, Indonesia, Malaysia and Vietnam each have a comparative advantage. Where Indonesia has a better comparative advantage than Thailand in the period 2011 to 2015. This result is different from the calculations made on competitive advantage (ECI in which Indonesia's natural rubber commodities are not more competitive than Thailand

Leading the next boom? competitive Eastern limb platinum supply

CSIR Research Space (South Africa)

McGill, JE

2010-07-01

Full Text Available in USD/troy oz (Data source: Johnson Matthey) Figure 4. Variation in nominal PGEs spot price from July 1992 till July 2010 in USD/troy oz (Data source: Johnson Matthey) PLATINUM IN TRANSITION ?BOOM OR BUST?4 each. In 1996 and 2003 merger attempts...

Drilling Down: An Examination of the Boom-Crime Relationship in Resource Based Boom Counties

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Rick Ruddell

2017-03-01

Full Text Available Objective to examine the boomcrime relationship in resourcebased boom counties and to propose socioeconomic and legal measures to reduce the boomtown effect. Methods dialectical approach to cognition of social phenomena allowing to analyze them in historical development and functioning in the context of the totality of objective and subjective factors that determined the choice of the following research methods formallogical comparativelegal survey interview focus groups generalized least squares method. Results The expansion in natural resource development in rural communities has led to a number of social problems in these places. The media community stakeholders as well as law enforcement and human service personnel have reported that the rapid growth in these communities leads to increased crime and other social ills. In order to better understand the boomcrime relationship index crimes in oil and natural gas producing counties in Montana and North Dakota were examined. Comparison of 2012 crime rates in a matched sample of counties revealed that crime rates were higher in oilimpacted counties. A prepost analysis found that violent crime in boom counties increased 18.5 between 2006 and 2012 while decreasing 25.6 in a matched sample of counties that had no oil or gas production. Inconsistent with the media portrayal of these communities as a new quotwild westquot we did not find a significant association between oil or natural gas production and property or violent crime in a series of OLS regression models. Scientific novelty for the first time the article uses index crimes in oil and natural gas producing counties in Montana and North Dakota to reveal the association between the rapid growth of towns and the crime rates. Practical significance the main provisions and conclusions of the article can be used in research and educational activity as well as for predicting the socialeconomic development of boomtowns.

Rubber friction on road surfaces: Experiment and theory for low sliding speeds

Energy Technology Data Exchange (ETDEWEB)

Lorenz, B.; Persson, B. N. J. [PGI, FZ Jülich, 52425 Jülich (Germany); Oh, Y. R.; Nam, S. K.; Jeon, S. H. [Hankook Tire Co. LTD., 112 Gajeongbuk-ro, Yuseong-gu, Daejeon 305-725 (Korea, Republic of)

2015-05-21

We study rubber friction for tire tread compounds on asphalt road surfaces. The road surface topographies are measured using a stylus instrument and atomic force microscopy, and the surface roughness power spectra are calculated. The rubber viscoelastic modulus mastercurves are obtained from dynamic mechanical analysis measurements and the large-strain effective modulus is obtained from strain sweep data. The rubber friction is measured at different temperatures and sliding velocities, and is compared to the calculated data obtained using the Persson contact mechanics theory. We conclude that in addition to the viscoelastic deformations of the rubber surface by the road asperities, there is an important contribution to the rubber friction from shear processes in the area of contact. The analysis shows that the latter contribution may arise from rubber molecules (or patches of rubber) undergoing bonding-stretching-debonding cycles as discussed in a classic paper by Schallamach.

Effect of electron beam irradiation on the properties of crosslinked rubbers

Science.gov (United States)

Banik, Indranil; Bhowmick, Anil K.

2000-05-01

Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature ( Tg) and storage modulus increased, while the elongation at the break and the loss tangent (tan δ) Tg decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy.

Particle reinforced composites from acrylamide modified blend of styrene-butadiene and natural rubber

Science.gov (United States)

Blends of styrene-butadiene rubber and natural rubber that provide balanced properties were modified with acrylamide and reinforced with soy protein particles. The rubber composites show improved mechanical properties. Both modified rubber and composites showed a faster curing rate. The crosslinking...

A review on the suitability of rubberized concrete for concrete bridge decks

Science.gov (United States)

Syamir Senin, Mohamad; Shahidan, Shahiron; Radziah Abdullah, Siti; Anting Guntor, Nickholas; Syazani Leman, Alif

2017-11-01

Road authorities manage a large population of ageing bridges, a substantial number of which fail to meet the current requirements either due to deterioration and other structural deficiencies or as a result of the escalating demands imposed by increased traffic. This problem is related to the dynamic load from vehicles. This problem can be solved by producing a type of concrete that can reduce the amplitude of oscillation or vibration such as rubberized concrete. Green construction has been a very important aspect in concrete production field in the last decade. One of the most problematic waste materials is scrap tires. The use of scrap tires in civil engineering is increasing by producing rubberized concrete. Rubberized concrete is a type of concrete that is mixed with rubber. The purpose of this review is to justify the suitability of rubberized concrete for concrete bridge decks. Several parameters named physical, chemical and mechanical properties were measured to ensure the suitability of rubberized concrete for concrete bridge decks. Rubberized concrete has similar workability to normal concrete. The rubber reduced the density and compressive strength of the concrete while increased the flexural strength, water absorption and damping ratio. The used of rubber in concrete beyond 20% is not recommended due to decreasing in compressive strength. Rubberized concrete recommended to be used in circumstances where vibration damping was required such as in bridge construction as shock-wave absorber.

Surface improvement of EPDM rubber by plasma treatment

Energy Technology Data Exchange (ETDEWEB)

Moraes, J H [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Silva Sobrinho, A S da [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Maciel, H S [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Dutra, J C N [EBO, Chemistry Division, IAE, CTA, Pca Mal Eduardo Gomes 50, 12228-904 Sao Jose dos Campos, S.P. (Brazil); Massi, M [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Mello, S A C [EBO, Chemistry Division, IAE, CTA, Pca Mal Eduardo Gomes 50, 12228-904 Sao Jose dos Campos, S.P. (Brazil); Schreiner, W H [Physics Department, UFPR, Centro Politecnico, 80060-000 Curitiba, P.R. (Brazil)

2007-12-21

The surface of ethylene-propylene-diene monomer (EPDM) rubber was treated in N{sub 2}/Ar and N{sub 2}/H{sub 2}/Ar RF plasmas in order to achieve similar or better adhesion properties than NBR (acrylonitrile-butadiene) rubber, nowadays used as thermal protection of rocket chambers. The surface properties were studied by contact angle measurements and by x-ray photoelectron spectroscopy (XPS). The treated surfaces of the EPDM samples show a significant reduction in the contact angle measurement, indicating an increase in the surface energy. XPS analyses show the incorporation of polar nitrogen- and oxygen-containing groups on the rubber surface. After plasma treatment the presence of oxygen is observed due to surface oxidation which occurs when the samples are exposed to the air. Atomic force microscopy and scanning electron microscopy analyses indicate a decrease in the EPDM rubber surface roughness, promoted by surface etching during the plasma treatment. Strength tests indicate improvement of about 30% and 110% in the adhesion strength for the plasma treated EPDM/polyurethane liner interface and for the EPDM/epoxy adhesive interface, respectively. The adhesion strength of the EPDM/liner is similar to that obtained for the NBR/liner, which indicates that EPDM rubber can safely be used as thermal protection of the solid propellant rocket chamber.

Surface improvement of EPDM rubber by plasma treatment

International Nuclear Information System (INIS)

Moraes, J H; Silva Sobrinho, A S da; Maciel, H S; Dutra, J C N; Massi, M; Mello, S A C; Schreiner, W H

2007-01-01

The surface of ethylene-propylene-diene monomer (EPDM) rubber was treated in N 2 /Ar and N 2 /H 2 /Ar RF plasmas in order to achieve similar or better adhesion properties than NBR (acrylonitrile-butadiene) rubber, nowadays used as thermal protection of rocket chambers. The surface properties were studied by contact angle measurements and by x-ray photoelectron spectroscopy (XPS). The treated surfaces of the EPDM samples show a significant reduction in the contact angle measurement, indicating an increase in the surface energy. XPS analyses show the incorporation of polar nitrogen- and oxygen-containing groups on the rubber surface. After plasma treatment the presence of oxygen is observed due to surface oxidation which occurs when the samples are exposed to the air. Atomic force microscopy and scanning electron microscopy analyses indicate a decrease in the EPDM rubber surface roughness, promoted by surface etching during the plasma treatment. Strength tests indicate improvement of about 30% and 110% in the adhesion strength for the plasma treated EPDM/polyurethane liner interface and for the EPDM/epoxy adhesive interface, respectively. The adhesion strength of the EPDM/liner is similar to that obtained for the NBR/liner, which indicates that EPDM rubber can safely be used as thermal protection of the solid propellant rocket chamber

Surface improvement of EPDM rubber by plasma treatment

Science.gov (United States)

Moraes, J. H.; da Silva Sobrinho, A. S.; Maciel, H. S.; Dutra, J. C. N.; Massi, M.; Mello, S. A. C.; Schreiner, W. H.

2007-12-01

The surface of ethylene-propylene-diene monomer (EPDM) rubber was treated in N2/Ar and N2/H2/Ar RF plasmas in order to achieve similar or better adhesion properties than NBR (acrylonitrile-butadiene) rubber, nowadays used as thermal protection of rocket chambers. The surface properties were studied by contact angle measurements and by x-ray photoelectron spectroscopy (XPS). The treated surfaces of the EPDM samples show a significant reduction in the contact angle measurement, indicating an increase in the surface energy. XPS analyses show the incorporation of polar nitrogen- and oxygen-containing groups on the rubber surface. After plasma treatment the presence of oxygen is observed due to surface oxidation which occurs when the samples are exposed to the air. Atomic force microscopy and scanning electron microscopy analyses indicate a decrease in the EPDM rubber surface roughness, promoted by surface etching during the plasma treatment. Strength tests indicate improvement of about 30% and 110% in the adhesion strength for the plasma treated EPDM/polyurethane liner interface and for the EPDM/epoxy adhesive interface, respectively. The adhesion strength of the EPDM/liner is similar to that obtained for the NBR/liner, which indicates that EPDM rubber can safely be used as thermal protection of the solid propellant rocket chamber.

RTV Silicone Rubber Degradation Induced by Temperature Cycling

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Xishan Wen

2017-07-01

Full Text Available Room temperature vulcanized (RTV silicone rubber is extensively used in power system due to its hydrophobicity and hydrophobicity transfer ability. Temperature has been proven to markedly affect the performance of silicone rubbers. This research investigated the degradation of RTV silicone rubber under temperature cycling treatment. Hydrophobicity and its transfer ability, hardness, functional groups, microscopic appearance, and thermal stability were analyzed using the static contact angle method, a Shore A durometer, Fourier transform infrared spectroscopy (FTIR, scanning electron microscopy (SEM, and thermogravimetry (TG, respectively. Some significant conclusions were drawn. After the temperature was cycled between −25 °C and 70 °C, the hydrophobicity changed modestly, but its transfer ability changed remarkably, which may result from the competition between the formation of more channels for the transfer of low molecular weight (LMW silicone fluid and the reduction of LMW silicone fluid in the bulk. A hardness analysis and FTIR analysis demonstrated that further cross-linking reactions occurred during the treatment. SEM images showed the changes in roughness of the RTV silicone rubber surfaces. TG analysis also demonstrated the degradation of RTV silicone rubber by presenting evidence that the content of organic materials decreased during the temperature cycling treatment.

Development of rubber gloves by radiation vulcanization

International Nuclear Information System (INIS)

Makuuchi, K.; Yoshii, F.; Ishigaki, I.; Mogi, M.; Saito, T.

1990-01-01

The processes of radiation vulcanization and production of protective rubber gloves for radioactive contamination are described. A newly developed sensitizing system consisting of 5 phr 2-ethylhexyl acrylate and 1 phr carbon tetrachloride was used to vulcanize natural rubber latex at 12 kGy. Transparent and soft gloves were obtained from the radiation vulcanized latex by a coagulant dipping process. The mechanical properties of the gloves meet Japanese Industrial Standard specification for protective gloves. Combustion analysis of the gloves revealed that the amount of evolved sulfur dioxide and remaining ashes are less than those from commercially available rubber gloves. A trial usage of the gloves at a nuclear power plant showed that the gloves were easy to use for delicate work without undergoing fatigue. (author)

Synthesis and characterization of silver nanoparticles in natural rubber

International Nuclear Information System (INIS)

Abu Bakar, N.H.H.; Ismail, J.; Abu Bakar, M.

2007-01-01

Silver nanoparticles are formed in natural rubber matrix via photo reduction of film cast from natural rubber latex (NRL) containing silver salt. The resulting NR-Ag nanocomposite is characterized using TEM, XRD and UV spectroscopic techniques. The nanoparticles, diameter ranging between 4 and 10 nm, are dispersed within distinct interfaces which correspond to the inter-particle boundaries of the NRL particles that form the matrix. The average width of the interfaces is 8 nm. X-ray diffraction (XRD) analysis confirms the nanoparticles as metallic silver of the face-centered cubic type. UV-vis absorption spectra show peaks characteristic of the surface plasmon resonance of nano-sized silver. A comparison with the results of formation of silver, obtained under similar reduction condition, in a series of matrices namely de-proteinized natural rubber latex (DNRL), NRL containing sodium dodecyl sulfate (SDS), aqueous solutions of bovain serum albumin and SDS, suggests that the protein in natural rubber is responsible for the formation of stable silver nanoparticles in the natural rubber (NR) matrix

Analysis of load monitoring system in hydraulic mobile cranes

Science.gov (United States)

Kalairassan, G.; Boopathi, M.; Mohan, Rijo Mathew

2017-11-01

Load moment limiters or safe load control systems or are very important in crane safety. The system detects the moment of lifting load and compares this actual moment with the rated moment. The system uses multiple sensors such as boom angle sensor, boom length sensor for telescopic booms, pressure transducers for measuring the load, anti-two block switch and roller switches. The system works both on rubber and on outriggers. The sensors measure the boom extension, boom angle and load to give as inputs to the central processing, which calculate the safe working load range for that particular configuration of the crane and compare it with the predetermined safe load. If the load exceeds the safe load, actions will be taken which will reduce the load moment, which is boom telescopic retraction and boom lifting. Anti-two block switch is used to prevent the two blocking condition. The system is calibrated and load tested for at most precision.

Review on Parameters Influencing the Rice Breakage and Rubber Roll Wear in Sheller

Directory of Open Access Journals (Sweden)

Prabhakaran P.

2017-09-01

Full Text Available The present review deals with parameters influencing the rice breakage during rice milling operations and the effect of rubber roll Sheller in rice husk removal process. The main objective of rice milling system is to remove the husk and bran layer to produce the white rice. In this process, rubber roll sheller is used to remove husk from the grains by friction process. If the rubber material is too soft, there may not be sufficient shear force to husk the paddy. Wear will be minimum for rubber material with high hardness but indeed it pronounce the breakage of rice. Hence, for efficient husking the rubber roll material should possess the balance of physico-mechanical properties. Rice breakage depends on several other parameters like the type of harvest, drying temperature, drying methods, physical characteristics of paddy, husking characteristics, paddy moisture content, rubber roller speed, rubber roll pressure, paddy feed rate and fissures. Rubber roll wear depends on the type of rubber material attached to the roller, feed rate, roller speed, pressure etc.

The Iron Law of Financial Markets: Self-fulfilling Prophecies and Speculative Booms and Busts

Directory of Open Access Journals (Sweden)

Ognjen Radonjić

2016-02-01

Full Text Available This paper discusses the factors which, in the absence of strong financial regulation, sustain the Iron Law of the Financial Markets asserting that speculative booms and busts occur more or less regularly from 17 century to the present. The first factor is that financial markets are self-fulfilling system. The second is that human nature does not change and is based on egoism, materialism, loss aversion, exaggerated hopes and fears, emulation, propensity to gamble, herd behavior and so on. Lastly, there is the extreme brevity of the financial memory. In order to enable economic authorities and/or individuals to detect timely that the unsustainable boom is under the way, we have identified the common features of historically recorded speculative episodes. Stages through which the system passes on its way from unsustainable rise to inevitable fall are: displacement, boom, overtrading, financial distress and discredit or revulsion.

Polybutadiene and Styrene-Butadiene rubbers for high-dose dosimetry

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Lucas N. [Instituto Federal de Educacao, Ciencia e Tecnologia de Goias-IFG,Campus Goiania, Goiania -GO (Brazil); Instituto de Pesquisas Energeticas e Nucleares -IPEN, Sao Paulo-SP (Brazil); Vieira, Silvio L. [Instituto de Fisica, Universidade Federal de Goias-UFG, Campus Samambaia, Goiania-GO (Brazil); Schimidt, Fernando [Instituto Federal de Educacao, Ciencia e Tecnologia de Goias-IFG,Campus Inhumas, Inhumas-GO (Brazil); Antonio, Patricia L.; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares -IPEN, Sao Paulo-SP (Brazil)

2015-07-01

Polybutadiene and Styrene-Butadiene are synthetical rubbers used widely for pneumatic tires manufacturing. In this research, the dosimeter characteristics of those rubbers were studied for application in high-dose dosimetry. The rubber samples were irradiated with doses of 10 Gy up to 10 kGy, using a {sup 60}Co Gamma Cell-220 system (dose rate of 1.089 kGy/h) and their readings were taken on a Fourier Transform Infrared Spectroscopy-FTIR system (model Frontier/Perkin Elmer). The ratios of two absorbance peaks were taken for each kind of rubber spectrum, Polybutadiene (1306/1130 cm{sup -1}) and Styrene-Butadiene (1449/1306 cm{sup -1}). The ratio calculated was used as the response to the irradiation, and is not uniform across the sample. From the results, it can be concluded for both rubbers: a) the dose-response curves may be useful for high-dose dosimetry (greater than 250 Gy); b) their response for reproducibility presented standard deviations lower than 2.5%; c) the relative sensitivity was higher for Styrene-Butadiene (1.86 kGy{sup -1}) than for Polybutadiene (1.81 kGy{sup -1}), d) for doses of 10 kGy to 200 kGy, there was no variation in the dosimetric response. Both types of rubber samples showed usefulness as high-dose dosimeters. (authors)

Radionuclide solubilities in boom clay. Final report, part 2 : a report produced for ONDRAF/NIRAS

Energy Technology Data Exchange (ETDEWEB)

Baker, S.; Baston, G.M.N.; Boult, K.A. [and others

2000-07-01

The release of radionuclides from a High Level Radioactive Waste repository situated in the Boom Clay at Mol would depend, in part, on their retardation within the Boom Clay. A number of parameters are required to assess such retardation; these include the solubilities of key radionuclides and their sorption behaviour. ONDRAF/NIRAS has identified neptunium, technetium, selenium, uranium and plutonium as elements for study. AEA Technology plc was requested to undertake a joint experimental and modelling study to determine the solubilities of these five elements under conditions representative of those in the Boom Clay (the in situ chemical conditions are pH{approx}8, Eh {approx} -230 mV). The work programme was carried out over three years, and for completeness this final report includes all the results.

Study on a Haptic Sensor Using MCF (Magnetic Compound Fluid) Electric Conductive Rubber

Science.gov (United States)

Zheng, Yaoyang; Shimada, Kunio

To provide a new composite material having a high degree of sensitivity regarding both electrical conduction and temperature for the field of robotics or sensing, we have developed magnetic rubber that contains a network-like magnetic cluster. We compared the temperature response of MCF rubber with others rubbers made under various experimental conditions, allowing us to find an optimum condition for making MCF rubber. The temperature response was obtained by an experimental equation. We also compared the electric conductivity of MCF rubber with that of ordinary electric conductive rubber and found that its electric sensitivity was lower at a small deformation, but increased at larger deformations. Therefore, MCF rubber has proven itself effective as a switching sensor when a small deformation is applied.

Rubber lining design for grinding mills: influence on economy and capacity

Energy Technology Data Exchange (ETDEWEB)

Nillson, G

1979-11-01

There is a difference in design parameters between steel linings and rubber linings for grinding mills. The basic design parameters for rubber are described and a comparison is made between steel and rubber in different applications. If a rubber lining is correctly designed, it will give at least the same capacity as any other type of lining. A rubber lining can often be made thinner than other types of lining and, in such cases, the increased mill diameter will increase the capacity. What has been said above regarding capacity applies equally to grinding efficiency. The grind can sometimes be changed by altering the lifter height and lifter profile. Rubber linings of the correct quality and design will always give improved lining economy, except for large primary ball mills. We trust that new designs and rubber qualities will change the picture in the future. What is said about lining economy is especially true when taking reduced downtime and maintenance into consideration. The lining must be designed to reduce sliding over the shell, which leads to heavy wear. When used for dry grinding, the adverse effects of temperature must be observed.

Effect of electron beam irradiation on the properties of crosslinked rubbers

Energy Technology Data Exchange (ETDEWEB)

Banik, Indranil; Bhowmick, Anil K. E-mail: anilkb@rtc.iitkgp.ernet.in

2000-05-01

Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature (T{sub g}) and storage modulus increased, while the elongation at the break and the loss tangent (tan {delta}){sub T{sub g}} decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy. (author)

Effect of electron beam irradiation on the properties of crosslinked rubbers

International Nuclear Information System (INIS)

Banik, Indranil; Bhowmick, Anil K.

2000-01-01

Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature (T g ) and storage modulus increased, while the elongation at the break and the loss tangent (tan δ) T g decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy. (author)

Fagoterapia frente a infecciones por Staphylococcus aureus meticilino resistente en ratones

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Jesús H Tamariz

Full Text Available Objetivos: Evaluar la actividad de los bacteriófagos frente a infecciones localizadas y sistémicas producidas por Staphylococcus aureus resistente a meticilina (MRSA Materiales y métodos. Se realizó un estudio de tipo experimental en 45 ratones de la cepa Balb/c divididos en nueve grupos de cinco individuos. Se aislaron diez bacteriófagos nativos a partir de muestras clínicas y efluentes hospitalarios, se evaluó su capacidad lítica y su espectro de actividad, en base a lo cual se seleccionaron seis fagos para los ensayos de fagoterapia. Adicionalmente, se empleó un bacteriófago de origen comercial. La fagoterapia fue evaluada mediante profilaxis y terapia de infecciones localizadas y sistémicas causadas por la inoculación de MRSA por vía subcutánea y endovenosa respectivamente. Se probó la efectividad de tres esquemas terapéuticos: monoterapia, cóctel de fagos en múltiples dosis y de cóctel de fagos en una sola dosis. También se comparó la actividad terapéutica de los fagos frente a vancomicina y clindamicina. Resultados. El cóctel de fagos y la terapia a diversas dosis fueron efectivos para prevenir y controlar infecciones localizadas por MRSA, su actividad fue similar a la de vancomicina y clindamicina. La dosis única del cóctel de fagos no logró controlar la infección localizada; asimismo, la fagoterapia no resultó efectiva en infecciones sistémicas. Conclusiones. La fagoterapia se proyecta como una alternativa viable frente a infecciones causadas por MRSA. Se requieren estudios que evalúen aspectos relacionados con la inocuidad de los fagos frente al paciente

Unraveling the mystery of natural rubber biosynthesis. Part II. Composition and growth of in vitro natural rubber using high-resolution size exclusion chromatography

Energy Technology Data Exchange (ETDEWEB)

Chiang, Cheng Ching K. [Univ. of Akron, OH (United States); Barkakaty, Balaka [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Puskas, Judit E. [Univ. of Akron, OH (United States); Xie, Wenshuang [The Ohio State Univ., Wooster, OH (United States); Cornish, Katrina [The Ohio State Univ., Wooster, OH (United States); Peruch, Federic [Univ. of Bordeaux, Pessac Cedex (France); Deffieux, Alain [Univ. of Bordeaux, Pessac Cedex (France)

2014-09-01

The superior properties of natural rubber (cis-1,4-polyisoprene [NR]) are a function of its structure and composition, properties that still remain a mystery and that are irreplaceable by any synthetic rubber. NR from guayule (Parthenium argentatum) has been gaining special interest for its hypoallergenic properties while maintaining superior mechanical properties that are commonly associated with the Brazilian rubber tree (Hevea brasiliensis), the most common source of NR. Techniques exist to isolate washed rubber particles (WRPs) that contain enzymatically active rubber transferase, to study NR biosynthesis, and previous work on the in vitroNRgrowth in Hevea has demonstrated the presence of around 50wt%of a low molecular weight ([MW], Mn <10 000 g/mol) fraction. Structural and compositional analyses of this low MW fraction in Hevea are challenging due to the high protein content. Here, we discuss the analysis and composition of guayule latex and WRPs using high-resolution Size Exclusion Chromatography. We also discuss the composition of the soluble fraction of inactive guayule latex using matrix-assisted laser desorption ionization/time of flight mass spectrometry.

Effect of Modified Rubber Particles Mixing Amount on Properties of Cement Mortar

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Gang Xue

2017-01-01

Full Text Available The crumb rubber cement mortar is prepared by the crumb rubber aggregates in 60 mesh which are modified by 1% polyvinyl alcohol (PVA solution. Some mechanical properties of cement mortar with different crumb rubber aggregate amounts are researched including compressive strength, flexural strength, the ratio of compressive strength to flexural strength, impact resistance, and dry contraction percentage. In our tests, we consider six kinds of the rubber contents, 0%, 7.5%, 15%, 19%, 22.5%, and 30%, respectively. The optimal mixing amount of crumb rubber is determined by measuring three indices, the ratio of compressive strength to flexural strength, impact resistance, and dry contraction percentage. It is shown by test that the ratio of compressive strength to flexural strength is the smallest when the mixing amount of rubber is 19%; meanwhile high impact resistance and rational drying shrinkage are observed. The optimal mixing amount of the rubber particles is 19% determined by this test.

Epoxidação "in situ" aplicada ao látex de borracha natural "In situ" epoxidation of natural rubber latex

Directory of Open Access Journals (Sweden)

Cristiane K. Santin

2012-01-01

Full Text Available O comportamento da borracha natural na forma látex frente à reação de epoxidação foi avaliado visando estabelecer as melhores condições reacionais sem a ocorrência de reações laterais, que promovem a coagulação do látex e o desenvolvimento de um aglomerado de borracha. Grupos epóxidos foram gerados através da reação de epoxidação a partir da formação in situ do ácido perfórmico. As amostras foram caracterizadas qualitativamente por espectroscopia de infravermelho (FTIR e o grau de modificação determinado por ressonância magnética nuclear de hidrogênio (1H-RMN. Análises de calorimetria exploratória diferencial (DSC demonstraram que a mobilidade da cadeia polimérica foi influenciada pela presença de grupos epóxidos, com aumento linear na temperatura de transição vítrea (Tg. Os resultados indicaram que a epoxidação do látex de borracha natural, sem a ocorrência de reações laterais, é possível e dependente das condições reacionais.Natural rubber latex was submitted to epoxidation reaction to establish the best reaction conditions without the occurrence of side reactions, which promote coagulation of the latex and development of an agglomerate of rubber. Epoxy groups were produced by in situ epoxidation with formic acid and hydrogen peroxide. The samples were characterized qualitatively by Fourier Transform Infrared (FTIR analysis and the degree of modification determined by Hydrogen Nuclear Magnetic Resonance Spectroscopy (1H-NMR analysis. A linear increase in the glass transition temperature (Tg was observed. The results show that the epoxidation of natural rubber latex is possible and depends on the reaction conditions.

Radiation modification of silicone rubber with glycidylmethacrylate

International Nuclear Information System (INIS)

Segura, Tania; Burillo, Guillermina

2013-01-01

The grafting of glycidilmethacrylate(GMA) was grafted onto silicone rubber (SR) by using the γ-ray pre-irradiation grafting method under different conditions. The effect of reaction time, total dose, reaction temperature and monomer concentration on the graft yield was studied. It was found that the degree of grafting can be controlled by adjusting these parameters. The chemical structure of SR before and after grafting was characterized using FTIR-ATR and SEM–EDS. The analysis revealed that the surface of the SR was uniformly covered by GMA and the cross-section analysis indicated that the grafting occurred in the bulk. Thermogravimetric analysis (TGA) showed that the graft copolymer was more thermally stable than polyglycidylmethacrylate but less stable than SR, and the DSC confirmed that the GMA was grafting onto silicone rubber. - Highlights: • A graft copolymer with silicone rubber was synthesized by gamma pre-irradiation method. • SEM–EDS analysis showed that the surface and the bulk of the new copolymer were grafted. • The thermal properties of the silicone rubber used were modified with grafting. • The new copolymer could be used to immobilize nucleophilic biomolecules

Rubber hand illusion under delayed visual feedback.

Directory of Open Access Journals (Sweden)

Sotaro Shimada

Full Text Available BACKGROUND: Rubber hand illusion (RHI is a subject's illusion of the self-ownership of a rubber hand that was touched synchronously with their own hand. Although previous studies have confirmed that this illusion disappears when the rubber hand was touched asynchronously with the subject's hand, the minimum temporal discrepancy of these two events for attenuation of RHI has not been examined. METHODOLOGY/PRINCIPAL FINDINGS: In this study, various temporal discrepancies between visual and tactile stimulations were introduced by using a visual feedback delay experimental setup, and RHI effects in each temporal discrepancy condition were systematically tested. The results showed that subjects felt significantly greater RHI effects with temporal discrepancies of less than 300 ms compared with longer temporal discrepancies. The RHI effects on reaching performance (proprioceptive drift showed similar conditional differences. CONCLUSIONS/SIGNIFICANCE: Our results first demonstrated that a temporal discrepancy of less than 300 ms between visual stimulation of the rubber hand and tactile stimulation to the subject's own hand is preferable to induce strong sensation of RHI. We suggest that the time window of less than 300 ms is critical for multi-sensory integration processes constituting the self-body image.

On some peculiarities of oil-resisting rubbers production from nitrile rubber of different composition by the use of Co60 gamma irradiation

International Nuclear Information System (INIS)

Mamedov, Sh.M.; Nelikzade, M.M.; Mamedov, A.A.

1976-01-01

The physicomechanical properties and swelling of vulcanizates were studied by means of radiation vulcanization. The test samples were preheated and formed by a press at 154 deg C for 3 min. Irradiation was performed in atmosphere on 60 Co (dosage 0.48 Mrad/hr). Irradiation caused decrease in tensile strength, as well as relative and permanent elongation; at the same time it considerably strengthened rubber hardness. All the rubber samples showed greater strength after irradiation under 5.7-13.8 Mrad. Depending on the dosage (3.6-13.8 Mrad), the relative and permanent elongation of vulcanizates obtained with the aid of altax was found to decrease, while strength and swelling increased. The swelling of rubber samples obtained with thiurad and thiuradaltax compounds decreased. Hence the advisability of using that rubber for manufacture of petroleum-resistant products

Effects of forests, roads and mistletoe on bird diversity in monoculture rubber plantations.

Science.gov (United States)

Sreekar, Rachakonda; Huang, Guohualing; Yasuda, Mika; Quan, Rui-Chang; Goodale, Eben; Corlett, Richard T; Tomlinson, Kyle W

2016-02-23

Rising global demand for natural rubber is expanding monoculture rubber (Hevea brasilensis) at the expense of natural forests in the Old World tropics. Conversion of forests into rubber plantations has a devastating impact on biodiversity and we have yet to identify management strategies that can mitigate this. We determined the life-history traits that best predict bird species occurrence in rubber plantations in SW China and investigated the effects of surrounding forest cover and distance to roads on bird diversity. Mistletoes provide nectar and fruit resources in rubber so we examined mistletoe densities and the relationship with forest cover and rubber tree diameter. In rubber plantations, we recorded less than half of all bird species extant in the surrounding area. Birds with wider habitat breadths and low conservation value had a higher probability of occurrence. Species richness and diversity increased logarithmically with surrounding forest cover, but roads had little effect. Mistletoe density increased exponentially with rubber tree diameters, but was unrelated to forest cover. To maximize bird diversity in rubber-dominated landscapes it is therefore necessary to preserve as much forest as possible, construct roads through plantations and not forest, and retain some large rubber trees with mistletoes during crop rotations.

Physical model of a floating trash boom to control aquatic weeds at the TVA Widows Creek Fossil Plant

International Nuclear Information System (INIS)

Hopping, P.N.

1991-01-01

This paper reports that the Tennessee Valley Authority (TVA) Widows Creek Fossil plant seasonally encounters adverse accumulations of aquatic weeds at the intakes of the condenser cooling water pumps. To reduce the accumulations, a floating trash boom has been proposed for the intakes. To evaluate the hydraulic feasibility of a boom, a physical model of the intakes has been built at the TVA Engineering Laboratory. The model was used to determine the boom alignment and depth of skimming needed to successfully deflect weeds away from the intakes and provide self-cleaning

Electromechanical responses of poly(3-thiopheneacetic acid/acrylonitrile-butadiene rubbers

Directory of Open Access Journals (Sweden)

2008-12-01

Full Text Available Acrylonitrile-butadiene rubber (NBR and blends of poly(3-thiopheneacetic acid/ acrylonitrile-butadiene rubber, P3TAA/NBR, were fabricated, and the electrorheological properties, dielectric, and electrical conductivities were investigated . The electrorheological properties were determined under an oscillatory shear mode in a frequency range of 0.1 to 100 rad/s at various electric field strengths, from 0 to 2 kV/mm, at a fixed 27°C to observe the effects of acrylonitrile content (ACN in the rubber systems and the conductive particle concentration in the blends. For the pure rubber systems, the storage modulus response (ΔG′ is linearly dependent on its dielectric constant (ε′, and increases with the ACN content. For the NBR/P3TAA blends, the storage modulus response varies nonlinearly with the dielectric constant. The bending responses of the rubbers and the blends were investigated in a vertical cantilever fixture. For the pure rubber system, the bending angle and the dielectrophoresis force vary linearly with electric field strength. For the blend system, the bending angle and the dielectrophoresis force vary nonlinearly with electric field strength.

Long rotation swidden systems maintain higher carbon stocks than rubber plantations

DEFF Research Database (Denmark)

Bruun, Thilde Bech; Berry, Nicholas; De Neergaard, Andreas

2018-01-01

in fallows were 1.5 ± 0.12 Mg C ha−1 yr−1 and 1.9 ± 0.14 Mg C ha−1 yr−1 in rubber plantations. When comparing time-averaged carbon stocks of swidden systems to rubber plantations with 30 year rotation periods, the stocks of swidden systems with rotation times of 5 and 10 years were 19% and 13% lower......Conversion of shifting cultivation to rubber (Hevea brasiliensis) plantations is one of the dominant land use changes in montane mainland areas of Southeast Asia, with the area of rubber expected to quadruple by 2050. However, the impacts of this transition on total ecosystem carbon stocks...... are poorly quantified. We undertook a chronosequence study to quantify changes in ecosystem carbon stocks following conversion from swidden agriculture to rubber plantations in Northern Laos. We measured above-ground biomass stocks and collected volume specific soil samples across rubber plantations...

Control Systems of Rubber Dryer Machinery Components Using Programmable Logic Control (PLC)

Science.gov (United States)

Hendra; Yulianto, A. S.; Indriani, A.; Hernadewita; Hermiyetti

2018-02-01

Application of programmable logic control (PLC) is widely used on the control systems in the many field engineering such as automotive, aviation, food processing and other industries [1-2]. PLC is simply program to control many automatic activity, easy to use, flexible and others. PLC using the ladder program to solve and regulated the control system component. In previous research, PLC was used for control system of rotary dryer machine. In this paper PLC are used for control system of motion component in the rubber dryer machinery. Component of rubber dryer machine is motors, gearbox, sprocket, heater, drying chamber and bearing. Principle working of rubber dryer machinery is wet rubber moving into the drying chamber by sprocket. Sprocket is driven by motors that conducted by PLC to moving and set of wet rubber on the drying chamber. Drying system uses greenhouse effect by making hanger dryer design in the form of line path. In this paper focused on motion control system motors and sensors drying rubber using PLC. The results show that control system of rubber dryer machinery can work in accordance control input and the time required to dry the rubber.

Prisons as Panacea or Pariah? The Countervailing Consequences of the Prison Boom on the Political Economy of Rural Towns

Directory of Open Access Journals (Sweden)

John M. Eason

2017-01-01

Full Text Available The nascent literature on prison proliferation in the United States typically reveals negative impacts for communities of color. Given that Southern rural communities were the most likely to build during the prison boom (1970–2010, however, a more nuanced understanding of prison impact is warranted. Using a dataset matching and geocoding all 1663 U.S. prisons with their Census-appointed place, this study explores the countervailing consequences of the prison boom on rural towns across multiple periods. For example, locales that adopted prisons at earlier stages of the prison boom era received a short-term boom compared to those that did not, but these effects were not lasting. Furthermore, later in the boom, prison-building protected towns against additional economic decline. Thus, neither entirely pariah nor panacea, the prison functions as a state-sponsored public works program for disadvantaged rural communities but also supports perverse economic incentives for prison proliferation. Methodological, substantive, theoretical, and policy implications regarding the intersection of race and punishment are explored.

Investigating the pore-water chemistry effects on the volume change behaviour of Boom clay

Science.gov (United States)

Deng, Y. F.; Cui, Y. J.; Tang, A. M.; Nguyen, X. P.; Li, X. L.; Van Geet, M.

The Essen site has been chosen as an alternative site for nuclear waste disposal in Belgium. The soil formation involved at this site is the same as at Mol site: Boom clay. However, owing to its geographical situation closer to the sea, Boom clay at Essen presents a pore water salinity 4-5 times higher than Boom clay at Mol. This study aims at studying the effects of pore water salinity on the hydro-mechanical behaviour of Boom clay. Specific oedometer cells were used allowing “flushing” the pore water in soil specimen by synthetic pore water or distilled water. The synthetic pore water used was prepared with the chemistry as that for the site water: 5.037 g/L for core Ess83 and 5.578 g/L for core Ess96. Mechanical loading was then carried out on the soil specimen after flushing. The results show that water salinity effect on the liquid limit is negligible. The saturation or pore water replacement under the in situ effective stress of 2.4 MPa does not induce significant volume change. For Ess83, hydro-mechanical behaviour was found to be slightly influenced by the water salinity; on the contrary, no obvious effect was identified on the hydro-mechanical behaviour of Ess96. This can be attributed to the higher smectite content in Ess83 than in Ess96.

Utilization of surface-treated rubber particles from waste tires

Energy Technology Data Exchange (ETDEWEB)

Smith, F.G. [Argonne National Lab., IL (United States). Energy Systems Div.]|[Environmental Technologies Alternatives, Inc., Lima, OH (United States)

1994-12-01

During a 12-month program, the author successfully demonstrated commercial applications for surface-treated rubber particles in two major markets: footwear (shoe soles and components) and urethane-foam carpet underlay (padding). In these markets, he has clearly demonstrated the ease of using R-4080 and R-4030 surface-treated rubber particles in existing manufacturing plants and processes and have shown that the material meets or exceeds existing standards for performance, quality, and cost-effectiveness. To produce R-4080 and R-4030, vulcanized rubber, whole-tire material is finely ground to particles of nominal 80 and mesh size respectively. Surface treatment is achieved by reacting these rubber particles with chlorine gas. In this report, the author describes the actual test and evaluations of the participant companies, and identifies other potential end uses.

New rubber qualification for the igniter adapter

Science.gov (United States)

Humpherys, Mark A.

1994-01-01

Kirkhill Rubber Company (KRC) has informed Thiokol Corporation that two raw materials used in the asbestos and silica filled acrylonitrile butadience rubber (NBR) formulation per STW 2621 are no longer available from their vendors. Agerite White (Di-beta-naphthyl-paraphenylene diamine), manufactured by B. F. Goodrich, is an antioxidant used in NBR. This raw material makes up roughly 1-2 percent of the finished product. KRC proposed that this raw material be replaced by Agerite Stalite S (mixture of octylated diphenylamines) distributed by R. T. Vanderbilt Co. Protox-166 zinc oxide, manufactured by Zinc Corporation of America, is an activator currently used in NBR. This material also makes up about 1-2 percent of the finished material. Protox-166 is an American process grade zinc oxide. It is proposed by KRC to replace Protox-166 with Kadox-930C, a French process grade zinc oxide. American process grades have an ASTM minimum purity of 99.0 percent; the French process grades have a minimum purity of 99.5 percent. Previous testing per WTP-0270 has demonstrated that the mechanical and thermal properties of the rubber with the new ingredients are comparable to the 'old' rubber. The test results are reported in TWR-61790. One igniter adapter, Part no. 7U77562-02 serial no. 2 was insulated per ETP-1206 using the new rubber formulation and a modified lay up and cure method to demonstrate that there is no impact on this process. The results of this demonstration are reported.

Natural rubber/high density polyethylene/ground rubber composites vulcanized by gamma irradiation

International Nuclear Information System (INIS)

Shaltout, N.A.; Abou zeid, M.M.; Khalil, A.M.; El Miligy, A.A.

2010-01-01

Natural rubber (NR) was blended mechanically with 50 phr high density polyethylene (HDPE). the mechanical, physical and thermal properties of NR/HDPE blend and its composites with different contents of ground tire rubber (GTR) before and after exposure to gamma irradiation to various doses up to 250 kGy were studied. Also, the change in structure morphology of irradiated NR/HDPE blend as well as NR/HDPE/GTR composites was examined by scanning electron microscope (SEM). The results showed that the substitution of a part of virgin NR with GTR decreases the mechanical and physical properties but not to the extent of deterioration . However, it was found that the mechanical and physical properties were improved after gamma irradiation . Composite of NR/GTR/HDPE (75/25/50) showed good properties. Scanning electron microscope showed homogeneity between the irradiated composites ingredients.

Performance of carbon fiber reinforced rubber composite armour against shaped charge jet penetration

Directory of Open Access Journals (Sweden)

Yue Lian-yong

2016-01-01

Full Text Available Natural rubber is reinforced with carbon fiber; the protective performances of the carbonfiber reinforced rubber composite armour to shaped charge jet have been studied based on the depth of penetration experiments. The craters on the witness blocks, the nature rubber based composite plates’ deformation and the Scanning Electron Microscopy for the hybrid fiber reinforced rubber plate also is analyzed. The results showed that the composite armour can affect the stability of the jet and made part of the jet fracture. The carbon fiber reinforced rubber composite armour has good defence ablity especially when the nature rubber plate hybrid 15% volume percentage carbonfiber and the obliquity angle is 68°. The hybrid fiber reinforced rubber composite armour can be used as a new kind of light protective armour.

Functionalization of Liquid Natural Rubber via Oxidative Degradation of Natural Rubber

Directory of Open Access Journals (Sweden)

Suhawati Ibrahim

2014-12-01

Full Text Available Natural rubber (NR is a high molecular weight natural polymer and can be degraded to liquid natural rubber (LNR leaving certain functional groups at the end of chains. In this study, LNR samples prepared via oxidative degradation using H2O2 and NaNO2 as reagents were found to have different end groups depending on the pH of the reaction medium. In an acidic medium, LNR with hydroxyl terminal groups was formed as the degradation reaction was initiated by hydroxyl radicals produced from decomposition of peroxynitrite acid. In contrast, a redox reaction took place in an alkaline medium to yield LNR with carbonyl terminal groups. The mechanisms of reaction are discussed and proposed to explain the formation of different end groups when reaction carried out in acidic and alkaline media. Chain degradation in an acidic medium seems to be more effective than in an alkaline medium, and thus yields LNR with lower Mn.

Effect of rubber polarity on selective wetting of carbon nanotubes in ternary blends

OpenAIRE

Le, H.H.; Parsaker, M.; Sriharish, M.N.; Henning, S.; Menzel, M.; Wiessner, S.; Das, A.; Do, Q.K.; Heinrich, G.; Radusch, H.J.

2015-01-01

Based on atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) analysis of the rubber-filler gel (wetting concept) the kinetics of selective wetting of carbon nanotubes (CNTs) in ternary styrene butadiene rubber (SBR)/butadiene rubber (BR)/natural rubber (NR) blends was qualitatively and quantitatively characterized. Almost all CNTs are found to be wetted by the non-polar NR but not by the other non-polar rubber like BR or weakly polar SBR. It was proposed that phos...

[Rubber band ligation in treatment of hemorrhoids: our experience].

Science.gov (United States)

Gaj, F; Biviano, I; Sportelli, G; Candeloro, L

2015-01-01

Hemorrhoids are a very common condition. The treatment depends upon persistence and severity of symptoms. For hemorrhoids of II and III grade the rubber band ligation may be therapeutic. Our aim is to report the outcomes of rubber band ligation of hemorrhoids, with a follow up of 6 months. A total of 50 patients underwent rubber band ligation for symptomatic hemorrhoids (grade II and III) without prolapse, between June 2012 and June 2014. All patients underwent plug test to rule out presence of rectal mucosal prolapse and were classified according to PATE classification (1). Each hemorrhoid was ligated with one rubber band through a ligator. All patients were evaluated immediately at the end of the procedure, after ten days and six months after the treatment. Patient's demographic and operative data were collected and analyzed. The mean patients age was 47.6±12.3 years (range 24-72). All procedures were performed without complications. Before rubber band ligation, 42 patients had rectal bleeding, 38 had perineal discomfort and 27 had itching. Ten days after the treatment, 12 patients presented self-limited rectal bleeding, but 10 of these had more hemorrhoids and underwent a second rubber band ligation. No patients complained perineal discomfort, and 8 patients had itching; 78% and 16% of patients respectively, experienced feeling of a foreign body inside the canal anal and anal pain. After 6 months, only 13 patients were occasionally symptomatic: 4 patients had rectal bleeding, 2 had perineal discomfort and 4 had itching. Three more patients presented both perineal discomfort and hitching. None had the feeling of a foreign body in anal canal or anal pain. Rubber band ligation is an efficacious, cost-effective and simple treatment for the second and third degree hemorrhoids without rectal mucosal prolapsed. In our hands, no severe complications developed and minor complications could be handled with ease.

Use of rubber asphalt binder with graded aggregate for seal coats

Energy Technology Data Exchange (ETDEWEB)

1979-01-01

It has been known that incorporating rubber particles into asphalt can improve highway pavement performance. This paper describes a test program on pavement construction using asphalts containing recycled rubber. During the summer 1978, eight test sections were constructed in parts of the Saskatchewan road system to evaluate seal coats using rubber-asphalt as a binder membrane and a graded aggregate as protective cover. Test sections were chosen to represent typical road surface types and different states of repair for each type. These types included prime subgrade, cold-mix on subgrade, primed granular base course, asphaltic concrete on granular base, and full depth asphaltic concrete. Problems with construction materials, techniques, and equipment are discussed. Performance and economics were evaluated to determine whether low cost cold mix and current seal coat surfaces could be replaced successfully and economically by this method of construction. It was shown that use of reclaimed rubber for rubberized asphalt seal coats on Saskatechewan highways is a practical construction application. The economic justification for rubber asphalt seals will be determined after a full assessment of performance. Initial indications are that Saskatchewan graded aggregates are a suitable cover material for the rubberized asphalt membranes used in the trials. 8 refs., 16 figs., 7 tabs.

Polymer Electrolyte Prepared from Highly Deproteinized Natural Rubber Having Epoxy Group

Science.gov (United States)

Klinklai, W.; Kawahara, S.; Isono, Y.; Mizumo, T.; Yoshizawa, M.; Ohno, H.

Deproteinized natural rubber having epoxy group (EDPNR) was applied to transport Li+ as a solid polymer electrolyte. The deproteinized natural rubber, incubated with proteolytic enzyme and surfactant, was subjected to epoxidation followed by oxidative depolymerization in latex stage. The resulting rubber was proved to be a liquid deproteinized natural rubber (LEDPNR) having polar epoxy groups, low Tg, low Mn and well-defined terminal units. Ionic conductivity of LEDPNR mixed with alkali metal salts was investigated through impedance analysis to clarify an effect of proteins present in the rubber. The ionic conductivity of the resulting LEDPNR depended on the kind of salts, their concentrations and temperature. The ionic conductivity of LEDPNR/lithium bis(trifluoromethan sulfonyl)imide (LiTFSI) was higher than that of LEDPNR/ lithium perchlorate (LiClO4). The difference in the ionic conductivity was attributed to the solubility of the salts as results of both high-resolution solid-state 13C-NMR spectroscopy and measurements of spin-lattice relaxation time. The conductivity of LEDPNR/LiTFSI was also dependent upon concentrations of LiTFSI and it reached the highest value at 20 wt%, which was different from the monotonic increase in the Li+ conductivity of liquid epoxidized natural rubber prepared from untreated natural rubber.

Características das Frentes Frias Causadoras de Chuvas Intensas no Leste de Santa Catarina

Directory of Open Access Journals (Sweden)

Marcelo Seluchi

Full Text Available Resumo O presente trabalho analisa as características principais das frentes frias causadoras de chuvas intensas no litoral do Estado de Santa Catarina, com a finalidade de melhorar o conhecimento e a previsão desse tipo de situação. Para isso, foi feita uma climatologia sinótica das frentes frias, utilizando reanálises CFSR do NCEP e dados de precipitação do CPTEC/INPE no período 1998-2010, a partir dos quais foram separados 5% das frentes frias mais chuvosas da série. Os resultados mostram que as frentes frias que provocam chuvas mais volumosas ocorrem ao longo de todo o ano, associadas à penetração de cavados frios, intensos e pouco baroclínicos nos níveis médios e altos da atmosfera. A lenta evolução da situação meteorológica permite a intensificação de um cavado na baixa troposfera, que provoca a gradativa intensificação da instabilidade termodinâmica sobre o leste de Santa Catarina, através da advecção de calor e umidade desde a Amazônia. A frente fria que dispara a precipitação apresenta forte inclinação nos baixos níveis e lento deslocamento. Em geral, a situação meteorológica apresenta poucas variações sazonais e pode ser identificada, em média, com pelo menos 48 h de antecedência.

Flexible diamond-like carbon film coated on rubber

NARCIS (Netherlands)

Pei, Y.T.; Bui, X.L.; Pal, J.P. van der; Martinez-Martinez, D.; Hosson, J.Th.M. De

2013-01-01

Dynamic rubber seals are major sources of friction of lubrication systems and bearings, which may take up to 70% of the total friction. The solution we present is to coat rubbers with diamond-like carbon (DLC) thin films by which the coefficient of friction is reduced to less than one tenth. Coating

Effect of concentrated epoxidised natural rubber and silica masterbatch for tyre application

Energy Technology Data Exchange (ETDEWEB)

Azira, A. A., E-mail: azira@lgm.gov.my; Kamal, M. M., E-mail: mazlina@lgm.gov.my [High Value Added Rubber Products and Nanostructured Materials, Stesen Penyelidikan RRIM, LGM 47000 Sungai Buloh, Selangor (Malaysia); Verasamy, D., E-mail: devaraj@lgm.gov.my [Environmental Technology & Sustainability, Technology & Engineering Division, Malaysian Rubber Board, Stesen Penyelidikan RRIM, LGM 47000 Sungai Buloh, Selangor (Malaysia)

2016-07-06

The availability of concentrated epoxidised natural rubber (ENR-LC) has provided a better opportunity for using epoxidised natural rubber (ENR) with silica to reinforce natural rubber for tyre application. ENR-LC mixed directly with silica to rubber by high speed stirrer without using any coupling agent. Some rubber compounds were prepared by mixing a large amount of precipitated amorphous white silica with natural rubber. The silica was prepared in aqueous dispersion and the filler was perfectly dispersed in the ENR-LC. The performance of the composites was evaluated in this work for the viability of ENR-LC/Si in tyre compounding. Compounding was carried out on a two roll mill, where the additives and curing agents was later mixed. Characterization of these composites was performed by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) for dispersion as well as mechanical testing. C-ENR/Si showed efficient as primary reinforcing filler in ENR with regard to modulus and tensile strength, resulting on an increase in the stiffness of the rubbers compared to ENR latex. Overall improvement in the mechanical properties for the ENR-LC over the control crosslinked rubber sample was probably due to synergisms of silica reinforcement and crosslinking of the polymeric matrix phase.

USE OF CRUMB RUBBER FROM USED CAR TIRES IN MINERAL ASPHALT MIXES

Directory of Open Access Journals (Sweden)

Andrzej Plewa

2014-11-01

Full Text Available With the development of the automotive industry the disposal of used tires is constantly growing problem. Storage of waste rubber is associated with a very long period of decomposition of rubber in the natural conditions. Simultaneously new technologies are developed every year, which in the future may significantly promote recycling of this type of materials. The crumb rubbery modification of the road bitumen is the one of the environmentally safe solutions of rubbery decomposition. Improvement of resistance of the crumb rubbery modification of the road asphalt mixtures is the very important ecological aspect of the future. The article presents the results of research on the fatigue life resistance of asphalt concretes AC16P and AC22P with asphalt-rubber binders. The above analyses have been based on the results of tests of fatigue life of mineral-rubber-asphalt mixes determined by the method of prismatic four-point bending (4PB-PR. Mineral-rubber -asphalt mixes have been diversified according to the amount of the additive of rubber fines in asphalt-rubber binder. On the basis of the test results have been proven improvements functional properties mineral-rubber-asphalt mixes compared with mineral-asphalt mixes with unmodified asphalt.

Ground rubber: Sorption media for ground water containing benzene and O-xylene

International Nuclear Information System (INIS)

Kershaw, D.S.; Pamukcu, S.

1997-01-01

The purpose of the current study is to examine the ability of ground rubber to sorb benzene and O-xylene from water contained with aromatic hydrocarbons. The study consisted of running both batch and packed bed column tests to determine the sorption capacity, the required sorption equilibration time, and the flow through utilization efficiency of ground rubber under various contact times when exposed to water contaminated with various amounts of benzene or O-xylene. Initial batch test results indicate that ground rubber can attain equilibrium sorption capacities up to 1.3 or 8.2 mg of benzene or O-xylene, respectively, per gram of tire rubber at solution equilibrium concentrations of 10 mg/L. Packed bed column tests indicate that ground tire rubber has on the average a 40% utilization rate when a hydraulic residence time of 15 min is used. Possible future uses of round rubber as a sorption media could include, but are not limited to, the use of ground rubber as an aggregate in slurry cutoff walls that are in contact with petroleum products. Ground rubber could also be used as a sorption media in pump-and-treat methodologies or as a sorption media in in-situ reactive permeable barriers

Effect of concentrated epoxidised natural rubber and silica masterbatch for tyre application

International Nuclear Information System (INIS)

Azira, A. A.; Kamal, M. M.; Verasamy, D.

2016-01-01

The availability of concentrated epoxidised natural rubber (ENR-LC) has provided a better opportunity for using epoxidised natural rubber (ENR) with silica to reinforce natural rubber for tyre application. ENR-LC mixed directly with silica to rubber by high speed stirrer without using any coupling agent. Some rubber compounds were prepared by mixing a large amount of precipitated amorphous white silica with natural rubber. The silica was prepared in aqueous dispersion and the filler was perfectly dispersed in the ENR-LC. The performance of the composites was evaluated in this work for the viability of ENR-LC/Si in tyre compounding. Compounding was carried out on a two roll mill, where the additives and curing agents was later mixed. Characterization of these composites was performed by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) for dispersion as well as mechanical testing. C-ENR/Si showed efficient as primary reinforcing filler in ENR with regard to modulus and tensile strength, resulting on an increase in the stiffness of the rubbers compared to ENR latex. Overall improvement in the mechanical properties for the ENR-LC over the control crosslinked rubber sample was probably due to synergisms of silica reinforcement and crosslinking of the polymeric matrix phase.

Radioisotopic determination methods of sulphur dispersion and sulphur blooming in rubber compounds

International Nuclear Information System (INIS)

Goraczka, W.; Koczorowska, E.

1997-01-01

It is well known that the concentration of sulphur in rubber compounds essentially effects the structure of the vulkanizate network. But there are no efficient and accurate methods to estimate the dispersion and migration (blooming) of curatives in raw rubber. In the work radioisotope methods have been analyzed to study the dispersion of curatives, physical and chemical processes in rubber and to optimize technical conditions of tire production. The radioactivity of the 35 S isotope introduced into rubber compounds has been measured by volumetric and surface methods. It was proved that the radioisotopic methods can be used in the studies. Experimental data of the effect of selected technological factors on these processes are presented. Rubber compounds containing soluble sulphur were made for such investigations. These methods permit detection of concentrations 10 -6 g of the radioactive isotope per 0.1 g of rubber compound. The sensitivity of these methods enables the investigation of radioisotope behaviour in rubber compounds during processing on an industrial scale without any hazards for workers

Enhancing the thermal stability of natural rubber/recycled ethylene–propylene–diene rubber blends by means of introducing pre-vulcanised ethylene–propylene–diene rubber and electron beam irradiation

International Nuclear Information System (INIS)

Nabil, H.; Ismail, H.

2014-01-01

Highlights: • New route of processing was introduced to optimise the thermal stability of NR/R-EPDM blends. • Pre-vulcanised EPDM and EB irradiation were introduced into NR/R-EPDM blends. • Thermal stability is obviously enhanced by applying these two techniques. • Applying new route of processing methods is clearly successful to NR/R-EPDM blends. - Abstract: Most rubber materials are subjected to oxidation. The rate of oxidation depends on the type of rubber, processing method, and end-use conditions. The oxidation of rubber can result in the loss of physical properties, such as tensile strength, elongation, and flexibility. Hence, the service life is determined by oxidation stability. Thermal properties are relevant to the potential use of polymeric materials in many consumer oriented applications. Thermo-oxidative ageing and thermogravimetric analysis (TGA) have been proven to be successful techniques in determining the thermal stability of polymers and polymer blends. In this article, preparation of a series of natural rubber/recycled ethylene–propylene–diene rubber (NR/R-EPDM) blends is described. Processing of the blends, by means of introducing pre-vulcanised EPDM and electron beam (EB) irradiation, was carried out. Two thermal analysis methods, namely thermo-oxidative ageing and thermogravimetric analysis, were conducted. The results indicated that pre-vulcanising EPDM for 1.45 min (ts − 2) is sufficient to gain the optimum retained tensile and elongation at break. It was simultaneously observed that the introduction of pre-vulcanised EPDM increased decomposition temperature and activation energy by showing optimum values at a pre-vulcanising time of 3.45 min (ts). In the latter study, the retained properties increased after EB irradiation. The results can be verified by the thermal decomposition temperature and their activation energy. The obtained TG profiles and the calculated kinetic parameters indicated that introducing EB irradiation

A Review on Using Crumb Rubber in Reinforcement of Asphalt Pavement

Science.gov (United States)

Mashaan, Nuha Salim; Ali, Asim Hassan; Karim, Mohamed Rehan; Abdelaziz, Mahrez

2014-01-01

An immense problem affecting environmental pollution is the increase of waste tyre vehicles. In an attempt to decrease the magnitude of this issue, crumb rubber modifier (CRM) obtained from waste tyre rubber has gained interest in asphalt reinforcement. The use of crumb rubber in the reinforcement of asphalt is considered as a smart solution for sustainable development by reusing waste materials, and it is believed that crumb rubber modifier (CRM) could be an alternative polymer material in improving hot mix asphalt performance properties. In this paper, a critical review on the use of crumb rubber in reinforcement of asphalt pavement will be presented and discussed. It will also include a review on the effects of CRM on the stiffness, rutting, and fatigue resistance of road pavement construction. PMID:24688369

A Review on Using Crumb Rubber in Reinforcement of Asphalt Pavement

Directory of Open Access Journals (Sweden)

Nuha Salim Mashaan

2014-01-01

Full Text Available An immense problem affecting environmental pollution is the increase of waste tyre vehicles. In an attempt to decrease the magnitude of this issue, crumb rubber modifier (CRM obtained from waste tyre rubber has gained interest in asphalt reinforcement. The use of crumb rubber in the reinforcement of asphalt is considered as a smart solution for sustainable development by reusing waste materials, and it is believed that crumb rubber modifier (CRM could be an alternative polymer material in improving hot mix asphalt performance properties. In this paper, a critical review on the use of crumb rubber in reinforcement of asphalt pavement will be presented and discussed. It will also include a review on the effects of CRM on the stiffness, rutting, and fatigue resistance of road pavement construction.

Seagrass Control Project: Containment Boom Evaluation. A Method to Protect Seawater Intakes from Seagrass Accumulation.

Science.gov (United States)

1983-10-01

containment booms at other mooring sites with significantly different physical and environ- mental conditions is recommended before full-scale application...deployment pattern for the different ship types. Modified procedures may also be needed to deploy the boom under a different set of physical and environmental... STPM Press Publ. New York, 353pp. 1980. Pulich, W., S. Barnes and P. Parker. Trace metal cycles in seagrass communities. pp 493-506 in M. Wiley, ed

Modeling and simulation of the agricultural sprayer boom leveling system

KAUST Repository

Sun, Jian; Miao, Yubin

2011-01-01

According to the agricultural precision requirements, the distance from sprayer nozzles to the corps should be kept between 50 cm to 70 cm. The sprayer boom also needs to be kept parallel to the field during the application process. Thus we can

Devulcanization of Waste Tire Rubber Using Amine Based Solvents and Ultrasonic Energy

OpenAIRE

Walvekar Rashmi; Afiq Zulkefly Mohammad.; Ramarad Suganti; Khalid Siddiqui

2018-01-01

This research project focuses on an alternative pathway of devulcanizing waste tire rubber by using amine based chemicals. Waste tire rubbers are known to be as toxic, non-degradable material due to their vulcanized crosslink carbon structure, and disposing of such waste could impose hazardous impacts on the environment. The current rubber recycling methods that are practiced today are rather uneconomical, non-environmentally friendly, and also producing recycled rubber with low quality due t...

Waste tyre rubberized concrete: properties at fresh and hardened state.

Science.gov (United States)

Aiello, M A; Leuzzi, F

2010-01-01

The main objective of this paper is to investigate the properties of various concrete mixtures at fresh and hardened state, obtained by a partial substitution of coarse and fine aggregate with different volume percentages of waste tyres rubber particles, having the same dimensions of the replaced aggregate. Workability, unit weight, compressive and flexural strength and post-cracking behaviour were evaluated and a comparison of the results for the different rubcrete mixtures were proposed in order to define the better mix proportions in terms of mechanical properties of the rubberized concrete. Results showed in this paper were also compared to data reported in literature. Moreover, a preliminary geometrical, physical and mechanical characterization on scrap tyre rubber shreds was made. The rubberized concrete mixtures showed lower unit weight compared to plain concrete and good workability. The results of compressive and flexural tests indicated a larger reduction of mechanical properties of rubcrete when replacing coarse aggregate rather than fine aggregate. On the other hand, the post-cracking behaviour of rubberized concrete was positively affected by the substitution of coarse aggregate with rubber shreds, showing a good energy absorption and ductility indexes in the range observed for fibrous concrete, as suggested by standard (ASTM C1018-97, 1997). 2010 Elsevier Ltd. All rights reserved.

Effect of vulcanization temperature and humidity on the properties of RTV silicone rubber

Science.gov (United States)

Wu, Xutao; Li, Xiuguang; Hao, Lu; Wen, Xishan; Lan, Lei; Yuan, Xiaoqing; Zhang, Qingping

2017-06-01

In order to study the difference in performance of room temperature vulcanized (RTV) silicone rubber in vulcanization environment with different temperature and humidity, static contact angle method, FTIR and TG is utilized to depict the properties of hydrophobicity, transfer of hydrophobicity, functional groups and thermal stability of RTV silicone rubber. It is found that different vulcanization conditions have effects on the characteristics of RTV silicone rubber, which shows that the hydrophobicity of RTV silicone rubber changes little with the vulcanization temperature but a slight increase with the vulcanization humidity. Temperature and humidity have obvious effects on the hydrophobicity transfer ability of RTV silicone rubber, which is better when vulcanization temperature is 5°C or vulcanization humidity is 95%. From the Fourier transform infrared spectroscopy, it can be concluded that humidity and temperature of vulcanization conditions have great effect on the functional groups of silicone rubber, and vulcanization conditions also have effect on thermal stability of RTV silicone rubber. When vulcanization temperature is 5°C or vulcanization humidity is 15% or 95%, the thermal stability of silicone rubber becomes worse.

Development of design method of thick rubber bearings for three-dimensional base isolation

International Nuclear Information System (INIS)

Yabana, Shuichi; Matuda, Akihiro

2000-01-01

Thick rubber bearings as 3-dimensional base isolators have been developed to reduce both horizontal and vertical seismic loads especially for equipment in Fast Breeder Reactors. In this report, a design method of thick rubber bearings is presented. To consider nonlinearity of vertical stiffness affected by vertical stress in the design of thick rubber bearings, Lindley's evaluation method of vertical stiffness is modified as an explicit form of vertical stress. We confirm that the presented method is efficient for design of the thick rubber bearings from comparing between test results and predicted values. Furthermore, rubber bearing tests are conducted with 1/3 scale models to evaluate mechanical properties of thick rubber bearings including ultimate limits. In the tests, horizontal and vertical characteristics of 1/3 scale model are compared with those of 1/6 scale model to discuss scale effect of test specimen. Ultimate limits such as failure shear strain of thick rubber bearings are obtained under various loading conditions. From the test results, we confirm that full scale thick rubber bearing to satisfy requirements is feasible. (author)

Experimental Investigation of a Large-Scale Low-Boom Inlet Concept

Science.gov (United States)

Hirt, Stefanie M.; Chima, Rodrick V.; Vyas, Manan A.; Wayman, Thomas R.; Conners, Timothy R.; Reger, Robert W.

2011-01-01

A large-scale low-boom inlet concept was tested in the NASA Glenn Research Center 8- x 6- foot Supersonic Wind Tunnel. The purpose of this test was to assess inlet performance, stability and operability at various Mach numbers and angles of attack. During this effort, two models were tested: a dual stream inlet designed to mimic potential aircraft flight hardware integrating a high-flow bypass stream; and a single stream inlet designed to study a configuration with a zero-degree external cowl angle and to permit surface visualization of the vortex generator flow on the internal centerbody surface. During the course of the test, the low-boom inlet concept was demonstrated to have high recovery, excellent buzz margin, and high operability. This paper will provide an overview of the setup, show a brief comparison of the dual stream and single stream inlet results, and examine the dual stream inlet characteristics.

Thermomechanical behaviour of boom clay

International Nuclear Information System (INIS)

Sultan, N.; Delage, P.; Cui, Y.J.

2000-01-01

Special attention has been recently paid on temperature effects on the behaviour of deep saturated clays, in relation with nuclear deep waste storage. However, few experimental data are presently available, and existing constitutive models need to be completed. This note is aimed at completing, both experimentally and theoretically, the understanding of the effects of the over-consolidation ration on the thermal volume changes of Boom clay (Belgium). The experimental data obtained here are in a good agreement with existing data. As a complement to existing data, they are used to develop a new elastoplastic model. The adoption of a second coupled plastic mechanism provides good simulations on a complex thermo-mechanical path. (authors)

Study on heat under dynamic loading of rubber

Directory of Open Access Journals (Sweden)

T. I. Igumenova

2016-01-01

Full Text Available A number of studies on heat buildup in tire rubber surface scan method samples using a thermal imaging camera. Investigated the exothermic chemical reaction mechanical destruction rubber when loading designs permanent cyclic stretching with deformation of the working zone 50%. Percentage of deformation of the working zone was chosen on the basis of the actual data on the stretch-compression zone "Rusk" tires, which is the maximum level difference of deformation during run-in. Experiment plan provided for periodic relaxation samples of at least 72 hours for more accurate simulation of operation process of structural products. Created and processed data on temperature changes in samples for bar and line profile for rubber compounds with the introduction of nanomodificator (fullerene-containing technical carbon in comparison with the control sample without him. The data obtained reflect the nature of heat depending on the composition of the compound. Identified common patterns of thermal nature of physicochemical process mechanical destruction rubbers. For rubber with nanomodifikatorom there has been an increase in the temperature interval reaction from a minimum to a maximum 2 degrees that is also linked to the rise in the average temperature of the reaction on the histogram also at 2-3 degrees of deformation under the same conditions and the level of cyclic loading. However, the temperature in the control sample that is associated with the beginning of the formation of hardened rubber structures, economies of Mallinza-Petrikeeva, occurs with delay twice compared with modified Fullerenes. Measurement of physic-mechanical indicators selected in the course of testing of samples showed the beginning of formation of structure with increased strength of samples in the sample temperature zone that corresponds to the thermal effect of èndotermičeskomu recombination reactions of macromolecules.

Impact Resistance of Rubberized Self-Compacting Concrete

Directory of Open Access Journals (Sweden)

Eehab Khalil

2015-04-01

Full Text Available Impact loads due to ship collision on irrigation structures is significantly decreasing their durability. Loss of material and degradation are quite common problems facing lock walls and piers. In the current research, rubberized self-compacting concrete (SCC was used to investigate problems associated with impact. SCC with cement kiln dust cement replacement was used for that purpose. Concrete specimens were prepared with different crumb rubber ratios of 10% (RSCC-10, 20% (RSCC-20, 30% (RSCC-30, and 40% (RSCC-40 sand replacement by volume. Standard compressive, flexure, and splitting strength tests were conducted to monitor the effect of the added rubber on concrete behavior. Moreover, impact testing program was applied to specific specimens, cylinder of diameter 200 mm and thickness 50 mm, according to ACI committee 544 procedures. The number of blows to first and ultimate cracks was determined. The relationship between the mechanical properties and impact resilience is also presented. With the increase in rubber percentage the resistance to impact increased, but there was a decrease in specimen strength and modulus of elasticity. The variation in results was discussed and mix RSCC-30 exhibited the best impact resistance, 3 times over control mix with 40% reduction of compressive strength.

The cross linking of EPDM and NBR rubber

Directory of Open Access Journals (Sweden)

Samardžija-Jovanović Suzana

2005-01-01

Full Text Available In the process of macromolecule cross linking, the choice of type and quantity of the components and the experimental conditions are important to obtain the new cross linked materials with better mechanical and chemical characteristics. The cross linking method depends on the rubber type and structure. Intermolecular cross linking results in the formation elastomer network. The basis of the cross linking process, between ethylene propylene diene rubber (EPDM and acrylonitrile butadiene rubber (NBR, is a chemical reaction. Fillers and other additives are present in different mass ratios in the material. The exploitation properties of the cross linked materials depend on the quantity of additive in the cross linked systems.

In situ chemical osmosis experiment in the Boom Clay at the Mol underground research laboratory

Science.gov (United States)

Garavito, A. M.; De Cannière, P.; Kooi, H.

Studies on the compatibility of Boom Clay with large amounts of nitrate- bearing bituminized radioactive waste have recently raised a particular interest for osmosis-induced effects in this reference formation in Belgium. Indeed, water flow and solute transport may be associated with several types of driving forces, or gradients (chemical, electrical, thermal), in addition to the hydraulic forces, resulting in the so-called coupled flows. Fluid flow caused by driving forces different than hydraulic gradients is referred to as osmosis. Chemical osmosis, the water flow induced by a chemical gradient across a semi-permeable membrane, can generate pressure increase. The question thus arises if there is a risk to create high pore pressures that could damage the near-field of medium-level waste (MLW) galleries, if osmotically driven water flows towards the galleries are produced by the release of large amounts of NaNO 3 (750 t) in the formation. To what extent a low-permeability clay formation such as the Boom Clay acts as an osmotic membrane is thus a key issue to assess the relevance of osmosis phenomena for the disposal of medium-level waste. An in situ osmosis experiment has been conducted at the H ADES underground research laboratory to determine the osmotic efficiency of Boom Clay at the field scale. A recently developed chemical osmosis flow continuum model has been used to design the osmosis experiment, and to interpret the water pressure measurements. Experimental data could be reproduced quite accurately by the model, and the inferred parameter values are consistent with independent determinations for Boom Clay. A rapid water pressure increase (but limited to about a 2 m water column) was observed after 12 h in the filter containing the more saline water. Then, the osmotically induced water pressure slowly decays on several months. So, the experimental results obtained in situ confirm the occurrence of non-hydraulic flow phenomena (chemical osmosis) in a low

Mapping Deciduous Rubber Plantation Areas and Stand Ages with PALSAR and Landsat Images

Directory of Open Access Journals (Sweden)

Weili Kou

2015-01-01

Full Text Available Accurate and updated finer resolution maps of rubber plantations and stand ages are needed to understand and assess the impacts of rubber plantations on regional ecosystem processes. This study presented a simple method for mapping rubber plantation areas and their stand ages by integration of PALSAR 50-m mosaic images and multi-temporal Landsat TM/ETM+ images. The L-band PALSAR 50-m mosaic images were used to map forests (including both natural forests and rubber trees and non-forests. For those PALSAR-based forest pixels, we analyzed the multi-temporal Landsat TM/ETM+ images from 2000 to 2009. We first studied phenological signatures of deciduous rubber plantations (defoliation and foliation and natural forests through analysis of surface reflectance, Normal Difference Vegetation Index (NDVI, Enhanced Vegetation Index (EVI, and Land Surface Water Index (LSWI and generated a map of rubber plantations in 2009. We then analyzed phenological signatures of rubber plantations with different stand ages and generated a map, in 2009, of rubber plantation stand ages (≤5, 6–10, >10 years-old based on multi-temporal Landsat images. The resultant maps clearly illustrated how rubber plantations have expanded into the mountains in the study area over the years. The results in this study demonstrate the potential of integrating microwave (e.g., PALSAR and optical remote sensing in the characterization of rubber plantations and their expansion over time.

Ground tire rubber as a stabilizer for subgrade soils.

Science.gov (United States)

2014-05-01

Over 250 million scrap tires are generated annually in the U.S. Historically, a significant portion of these tires : have been processed into finely ground tire rubber (GTR), or crumb rubber, for use as an additive in hot mix asphalt : (HMA) pavement...

Oxygen Plasma Treatment of Rubber Surface by the Atmospheric Pressure Cold Plasma Torch

DEFF Research Database (Denmark)

Lee, Bong-ju; Kusano, Yukihiro; Kato, Nobuko

1997-01-01

adhesive. The adhesion property was improved by treatment of the rubber compound with plasma containing oxygen radicals. Physical and chemical changes of the rubber surface as a result of the plasma treatment were analyzed by field emission scanning electron microscopy (FE-SEM) and fourier transform......A new application of the atmospheric cold plasma torch has been investigated. Namely, the surface treatment of an air-exposed vulcanized rubber compound. The effect of plasma treatment was evaluated by the bondability of the treated rubber compound with another rubber compound using a polyurethane...

Effect of gamma irradiation on the properties of natural rubber/styrene butadiene rubber blends

Directory of Open Access Journals (Sweden)

A.B. Moustafa

2016-09-01

Full Text Available Blends of natural rubber (NR with styrene butadiene rubber (SBR with varying ratios have been prepared. Vulcanization of the prepared blends has been induced by irradiation of gamma rays with varying doses up to 250 kGy. Mechanical properties, namely tensile strength, tensile modulus at 100% elongation, elongation at break have been followed up as a function of irradiation dose as well as blend composition. Physical properties, namely gel fraction and swelling number have been followed up using benzene as a solvent. Thermal measurements namely thermogravimetric analysis were carried out. The results indicated that the addition of NR has improved the properties of NR / SBR blends. Also NR/SBR blend is thermally stable than NR alone.

Design of an Indoor Sonic Boom Simulator at NASA Langley Research Center

Science.gov (United States)

Klos, Jacob; Sullivan, Brenda M.; Shepherd, Kevin P.

2008-01-01

Construction of a simulator to recreate the soundscape inside residential buildings exposed to sonic booms is scheduled to start during the summer of 2008 at NASA Langley Research Center. The new facility should be complete by the end of the year. The design of the simulator allows independent control of several factors that create the indoor soundscape. Variables that will be isolated include such factors as boom duration, overpressure, rise time, spectral shape, level of rattle, level of squeak, source of rattle and squeak, level of vibration and source of vibration. Test subjects inside the simulator will be asked to judge the simulated soundscape, which will represent realistic indoor boom exposure. Ultimately, this simulator will be used to develop a functional relationship between human response and the sound characteristics creating the indoor soundscape. A conceptual design has been developed by NASA personnel, and is currently being vetted through small-scale risk reduction tests that are being performed in-house. The purpose of this document is to introduce the conceptual design, identify how the indoor response will be simulated, briefly outline some of the risk reduction tests that have been completed to vet the design, and discuss the impact of these tests on the simulator design.

Influence the Rubber Seed Type and Altitude on Characteristic of Seed, Oil and Biodiesel

Directory of Open Access Journals (Sweden)

Salni Salni

2017-06-01

Full Text Available This research studies the influence of the type of rubber seed that is superior and local, altitude plant in South Sumatra province to the characteristic of seed, oil and biodiesel (methyl ester. Rubber plants planted from local rubber seed by seeds seedlings and superior rubber seed by selected clones. In the study, rubber plants planted at a different altitude, namely in Banyuasin district (18 m above sea level, Prabumulih District (176 m above sea level and Lahat District (627 m above sea level. The results showed that the weight of the flour, the water content and ash content in the local rubber seeds larger than the superior rubber seed for all altitude, but oil content a large in the superior rubber seeds. The major of fatty acids in the rubber seed oil in all types and altitude are a linoleic acid with a different percentage except local rubber seed oil from Lahat district with the large percentage of octadecanoic acid. Free fatty acids in the oil from the superior seeds rubber of 13.897-15.494 % large than local rubber seed oil was found 9.786-10.399 % for all altitude. By esterification process using sulfuric acid catalyst, Free Fatty Acid (FFA can be reduced to ≤ 2 %. The methyl ester made from the transesterification process of rubber seed oil after esterification using methanol and sodium hydroxide as catalyst. Analysis of methyl esters includes cetane index, flash point, kinematic viscosity, carbon residue, density, moisture content, water and sediment content and distillation compared with SNI 7182 and ASTM 6751-02.  The result indicated that the quality of methyl ester from superior rubber seed oil in the Banyuasin and Prabumulih district better than another methyl ester. The types of rubber seed altitude affect the characteristics of the seed, oil and methyl ester  but the altitude are not significantly different. Keywords: rubber seed, type, altitude, oil, biodiesel Article History: Received March 21st 2017; Received in

Behavior of Rubber Materials under Exposure to High Electric Fields

DEFF Research Database (Denmark)

Candela Garolera, Anna; Holbøll, Joachim; Henriksen, M,

2013-01-01

The effect of high electrical stress on rubber materials is investigated by performing breakdown tests and tracking resistance tests on selected samples. The study is focused on the relationship between the dielectric strength and the thickness of the samples, as well as the influence of the inte......The effect of high electrical stress on rubber materials is investigated by performing breakdown tests and tracking resistance tests on selected samples. The study is focused on the relationship between the dielectric strength and the thickness of the samples, as well as the influence...... of the interfaces between different layers of material. Tracking resistance tests are also performed on the rubber material. The purpose is to provide a complete study of the applicability of the rubber material in thunderstorm environments....

High damping properties of magnetic particles doped rubber composites at wide frequency

Energy Technology Data Exchange (ETDEWEB)

Tian, Ye, E-mail: schtiany@163.com [Research Center for Engineering Technology of Polymeric Composites of Shanxi Province, North University of China, Taiyuan 030051 (China); College of Material Science and Engineering, North University of China, Taiyuan 030051 (China); Liu, Yaqing, E-mail: lyq@nuc.edu.cn [Research Center for Engineering Technology of Polymeric Composites of Shanxi Province, North University of China, Taiyuan 030051 (China); College of Material Science and Engineering, North University of China, Taiyuan 030051 (China); He, Minhong; Zhao, Guizhe; Sun, Youyi [Research Center for Engineering Technology of Polymeric Composites of Shanxi Province, North University of China, Taiyuan 030051 (China); College of Material Science and Engineering, North University of China, Taiyuan 030051 (China)

2013-05-15

Highlights: ► A new kind of permanent magnetic rubber was prepared. ► The microstructure and magnetic properties were investigated. ► The mechanical and damping properties were discussed. ► The new material is expected to be an isolator material to a changed frequency. - Abstract: A new kind of rubber composite was prepared by doping SrFe{sub 12}O{sub 19} nanoparticles coated with silane coupling agents (Si-69) into nitrile butadiene rubber (NBR) matrix, which was characterized by the scanning electron microscopy and X-ray spectroscopy. The results showed that the SrFe{sub 12}O{sub 19} nanoparticles were well dispersed in rubber matrix. Furthermore, the mechanical and magnetic properties of the rubber composites were investigated, in which the high tensile strength (15.8 MPa) and high saturation magnetization (22.9 emu/g) were observed. What is more, the high loss factor of the rubber composites was also obtained in a wide frequency range (0–100 Hz) at high loading (80 phr). The result is attributed to that the permanent magnetic field in rubber nanocomposites can absorb shock energy. These results indicate that the new kind of permanent magnetic rubber is expected to be a smart isolator material, in which the isolator will be able to adapt to a changed frequency.

Irradiating rubber laminate containing sensitive agent in layer

International Nuclear Information System (INIS)

Bohm, G.G.A.

1979-01-01

Rubber compounds may be sensitized to cure or partially cure when subjected to irradiation. If certain layers of a rubber laminate are treated with sensitizing materials and other layers wth densensitizing materials a composite is produced having cured and uncured layers after it has been subjected to irradiation. This technique enables the production of composite laminates in which predetermined layers have predetermined physical characteristics which are desirable in the manufacture of the ultimate end product, for example, automotive tires. Several chemicals have been found to accelerate the cure of rubber compounds by irradiation and several have been found which inhibit the cure. Paradichlorobenzene (PDCB) and certain of the thioetherpolythiols are effective cure promotors. Effective retarders include aromatic oils, sulfur, sulfur cure accelerators and some rubber antioxidants and/or antiozonants of the substituted diphenylamine type. The dosage of irradiation is dependent upon several variables: the type of rubber, the promotor or retarder utilized, the level of the promotor or retarder, the thickness of the layer of material, the thickness of adjacent layers of materials, the sequence of the layers of material, the number of the layers of material and whether the irradiation is applied to one or both sides of the composite strip. The dosage may be controlled by the amount of energy employed so that the electrons do not completely penetrate the entire strip. This results in the irradiaton of part of the strip, but not the entire strip. (LL)

No pain relief with the rubber hand illusion.

Directory of Open Access Journals (Sweden)

Rahul Mohan

Full Text Available The sense of body ownership can be easily disrupted during illusions and the most common illusion is the rubber hand illusion. An idea that is rapidly gaining popularity in clinical pain medicine is that body ownership illusions can be used to modify pathological pain sensations and induce analgesia. However, this idea has not been empirically evaluated. Two separate research laboratories undertook independent randomized repeated measures experiments, both designed to detect an effect of the rubber hand illusion on experimentally induced hand pain. In Experiment 1, 16 healthy volunteers rated the pain evoked by noxious heat stimuli (5 s duration; interstimulus interval 25 s of set temperatures (47°, 48° and 49°C during the rubber hand illusion or during a control condition. There was a main effect of stimulus temperature on pain ratings, but no main effect of condition (p = 0.32, nor a condition x temperature interaction (p = 0.31. In Experiment 2, 20 healthy volunteers underwent quantitative sensory testing to determine heat and cold pain thresholds during the rubber hand illusion or during a control condition. Secondary analyses involved heat and cold detection thresholds and paradoxical heat sensations. Again, there was no main effect of condition on heat pain threshold (p = 0.17, nor on cold pain threshold (p = 0.65, nor on any of the secondary measures (p<0.56 for all. We conclude that the rubber hand illusion does not induce analgesia.

GRAFT COPOLYMERIZATION OF OLYGOESTERACRYLATES WITH LIQUID RUBBER AND COPOLYMER’S CHARACTERISTICS

Directory of Open Access Journals (Sweden)

Y. A. Anisimov

2015-02-01

Full Text Available The kinetic of graft copolymerization of threeethyleneglicoldimethacrylate and di threeethyleneglicolftalatedimethacrylate with liquid buthadiene rubber have been studied as a function of the olygomers composition. The experimental constants of copolymerization rate and efficiency olygoesteracrylates graft to liquid rubber were determined. The ihfluence of olygoesteracrylates’ nature on the grafting efficiency to olygomer rubber is determined and the strength characteristics are found.

Development of SBR-Nano clay Composites with Epoxidized Natural Rubber as Compatibilizer

International Nuclear Information System (INIS)

Rajasekar, R.; Das, Ch.K.; Gert Heinrich, G.; Das, A.

2009-01-01

The significant factor that determines the improvement of properties in rubber by the incorporation of nano clay is its distribution in the rubber matrix. The simple mixing of nonpolar rubber and organically modified nano clay will not contribute for the good dispersion of nano filler in the rubbery matrix. Hence a polar rubber like epoxidized natural rubber (ENR) can be used as a compatibilizer in order to obtain a better dispersion of the nano clay in the matrix polymer. Epoxidized natural rubber and organically modified nano clay composites (EC) were prepared by solution mixing. The nano clay employed in this study is Cloisite 20A. The obtained nano composites were incorporated in styrene butadiene-rubber (SBR) compounds with sulphur as a curing agent. The morphology observed through X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) shows that the nano clay is highly intercalated in ENR, and further incorporation of EC in SBR matrix leads to partial exfoliation of the nano clay. Dynamic mechanical thermal analysis showed an increase in storage modulus and lesser damping characteristics for the compounds containing EC loading in SBR matrix. In addition, these compounds showed improvement in the mechanical properties.

Study on mechanical properties of laminated rubber bearing with small shape factor

International Nuclear Information System (INIS)

Mazda, T.; Ootori, Y.; Yabana, S.; Hirata, K.; Ishida, K.

1995-01-01

Laminated rubber bearings with a small shape factor are regarded as one of the most promising isolation devices to reduce the vertical seismic load of a nuclear power plant. In this study, three types of natural rubber bearings with different aspect ratios (diameter/total thickness of rubber) and one high-damping rubber bearing are tested under varied loading conditions. Basic characteristics and ultimate characteristics of the bearings are made clear, and applicability of estimation formula and analysis method are verified

Viscoelasticity evaluation of rubber by surface reflection of supersonic wave.

Science.gov (United States)

Omata, Nobuaki; Suga, Takahiro; Furusawa, Hirokazu; Urabe, Shinichi; Kondo, Takeru; Ni, Qing-Qing

2006-12-22

The main characteristic of rubber is a viscoelasticity. So it is important to research the characteristic of the viscoelasticity of the high frequency band for the friction between a rubber material and the hard one with roughness, for instance, the tire and the road. As for the measurement of the viscoelasticity of rubber, DMA (dynamic mechanical analysis) is general. However, some problems are pointed out to the measurement of the high frequency band by DMA. Then, we evaluated the viscoelasticity characteristic by the supersonic wave measurement. However, attenuation of rubber is large, and when the viscoelasticity is measured by the supersonic wave therefore, it is inconvenient and limited in a past method by means of bottom reflection. In this report, we tried the viscoelasticity evaluation by the method of using complex surface reflection coefficient and we compared with the friction coefficient under wide-range friction velocity. As a result, some relationships had been found for two properties. We report the result that character of viscoelasticity of rubber was comparable to friction coefficient.

Microclimate and development of 'Conilon' coffee intercropped with rubber trees

Directory of Open Access Journals (Sweden)

Fábio Luiz Partelli

2014-11-01

Full Text Available The objective of this work was to evaluate the influence of intercropping 'Conilon' coffee (Coffea canephora with rubber trees on coffee tree microclimate, nutrition, growth, and yield. Rubber trees were planted in two double rows 33 m apart, with 4x2.3 m spacing between plants. Treatments consisted of the distances from the coffee plants to the rubber trees: 3, 6, 9, 12, and 15 m. Measurements of atmospheric variables (temperature, irradiance, and relative humidity, leaf nutrient concentration, internode length of plagiotropic and orthotropic branches, individual leaf area, chlorophyll content, and yield were performed. Intercropping promotes changes in the microclimatic conditions of coffee plants close to rubber trees, with reduction of temperature and irradiance level and increase in air relative humidity. The proximity of the coffee tree to the rubber trees promotes the elongation of the plagiotropic and orthotropic branches and increases the individual leaf area; however, it does not affect leaf concentrations of N, K, Mg, Fe, Zn, and B in 'Conilon' coffee and does not have a negative impact on yield.

Vulcanization Kinetics of Natural Rubber Based On Free Sulfur Determination

Directory of Open Access Journals (Sweden)

Abu Hasan

2013-05-01

Full Text Available The determination of free sulfur in the rubber vulcanizates provided significant representation of vulcanization reaction. In this research, the effects of vulcanization temperature, the mixing method of carbon black into rubber, the ingredients mixing sequence and the type of carbon black were studied on masticated and milled natural rubber in which the reaction was observed by un-reacted sulfur determination. The results showed that higher vulcanization temperature provided faster vulcanization reaction and greater reaction rate constant. Similarly, the mixing sequence of ingredient and carbon black into rubber influenced the rate of vulcanization reaction. The subsequent ingredients mixing sequence, in this case, resulted in higher vulcanization rate compared to that of the simultaneous one. However, the mixing method of carbon black into rubber brought small effect on the rate of vulcanization reaction. The type of carbon black applied was observed to influence the reaction rate of vulcanization. Smaller particle sizes of carbon black gave larger reaction rate constant. In this case, the type of carbon black N 330 gave faster vulcanization rate than that of N 660.

EPDM Rubber Modified by Nitrogen Plasma Immersion Ion Implantation.

Science.gov (United States)

Kondyurin, Alexey

2018-04-24

Ethylene-propylene diene monomer rubber (EPDM) was treated by plasma immersion ion implantation (PIII) with nitrogen ions of 20 keV energy and fluence from 10 13 to 10 16 ions/cm². The Fourier-transform infrared attenuated total reflection spectra, atomic force microscopy and optical microscopy showed significant structure changes of the surface. The analysis of an interface of PIII treated EPDM rubber with polyurethane binder showed a cohesive character of the adhesion joint fracture at the presence of solvent and interpreted as covalent bond network formation between the PIII treated rubber and the adhesive.

EPDM Rubber Modified by Nitrogen Plasma Immersion Ion Implantation

Directory of Open Access Journals (Sweden)

Alexey Kondyurin

2018-04-01

Full Text Available Ethylene-propylene diene monomer rubber (EPDM was treated by plasma immersion ion implantation (PIII with nitrogen ions of 20 keV energy and fluence from 1013 to 1016 ions/cm2. The Fourier-transform infrared attenuated total reflection spectra, atomic force microscopy and optical microscopy showed significant structure changes of the surface. The analysis of an interface of PIII treated EPDM rubber with polyurethane binder showed a cohesive character of the adhesion joint fracture at the presence of solvent and interpreted as covalent bond network formation between the PIII treated rubber and the adhesive.

Effect of rubber polarity on selective wetting of carbon nanotubes in ternary blends

Directory of Open Access Journals (Sweden)

H. H. Le

2015-11-01

Full Text Available Based on atomic force microscopy (AFM and Fourier transform infrared spectroscopy (FTIR analysis of the rubber-filler gel (wetting concept the kinetics of selective wetting of carbon nanotubes (CNTs in ternary styrene butadiene rubber (SBR/butadiene rubber (BR/natural rubber (NR blends was qualitatively and quantitatively characterized. Almost all CNTs are found to be wetted by the non-polar NR but not by the other non-polar rubber like BR or weakly polar SBR. It was proposed that phospholipids, which are linked to the α-terminal of NR can interact with the CNT surface through cation-π interactions forming strong bonding between NR and CNTs. Using the corrected surface tension value of NR, which involves the effect of phospholipids found in our previous work the selective wetting of CNTs in ternary rubber blends can be well predicted using the Z-model for a thermodynamic equilibrium state. By replacing the non-polar BR by a polar rubber like nitrile butadiene rubber (NBR as a blend component CNTs are wetted by NBR slightly more than by NR thanks to the strong interaction between CNTs and nitrile groups of NBR. SBR remains unbound to CNTs in both blends.

EVALUATION OF TIRE RUBBER DISPOSAL IN CONCRETE FOR PAVEMENTS

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Rosa Cristina Cecche Lintz

2009-01-01

Full Text Available The production of waste by the tire industry has been a growing problem, indicating the need for its reuse. More than thirty million tires are discharged per year in Brazil, where regulation for the environment states that for each four new tires, five unusable ones must be adequately disposed by manufacturers and importers. Paving consumes an extremely large quantity of materials, which can be the source of rational application of waste and rejected materials. Research shows that tire rubber can be added to asphalt, which increases its durability and improves pavement quality and safety conditions by absorbing the rubber elastic properties, and also be used for architectural applications, among others. This study deals with the addition of rubber fibers from tire crushing in concrete for roadway pavements in order to provide proper indication about the alternative material disposal through an evaluation of the mechanical behavior of the modified concrete. Different concrete mixes were produced, within which, part of fine aggregates were substituted by tire rubber and mechanical experiment tests were performed, which show that, due to great resistance losses, the disposal of this alternative material in concrete should be considered for light traffic pavements, with the addition of rubber ranging up to 10% in mass.

EVALUATION OF TIRE RUBBER DISPOSAL IN CONCRETE FOR PAVEMENTS

Directory of Open Access Journals (Sweden)

Rosa Cristina Cecche Lintz

2009-12-01

Full Text Available The production of waste by the tire industry has been a growing problem, indicating the need for its reuse. More than thirty million tires are discharged per year in Brazil, where regulation for the environment states that for each four new tires, five unusable ones must be adequately disposed by manufacturers and importers. Paving consumes an extremely large quantity of materials, which can be the source of rational application of waste and rejected materials. Research shows that tire rubber can be added to asphalt, which increases its durability and improves pavement quality and safety conditions by absorbing the rubber elastic properties, and also be used for architectural applications, among others. This study deals with the addition of rubber fibers from tire crushing in concrete for roadway pavements in order to provide proper indication about the alternative material disposal through an evaluation of the mechanical behavior of the modified concrete. Different concrete mixes were produced, within which, part of fine aggregates were substituted by tire rubber and mechanical experiment tests were performed, which show that, due to great resistance losses, the disposal of this alternative material in concrete should be considered for light traffic pavements, with the addition of rubber ranging up to 10% in mass.

Behaviour of Steel Fibre Reinforced Rubberized Continuous Deep Beams

Science.gov (United States)

Sandeep, MS; Nagarajan, Praveen; Shashikala, A. P.

2018-03-01

Transfer girders and pier caps, which are in fact deep beams, are critical structural elements present in high-rise buildings and bridges respectively. During an earthquake, failure of lifeline structures like bridges and critical structural members like transfer girders will result in severe catastrophes. Ductility is the key factor that influences the resistance of any structural member against seismic action. Structural members cast using materials having higher ductility will possess higher seismic resistance. Previous research shows that concrete having rubber particles (rubcrete) possess better ductility and low density in comparison to ordinary concrete. The main hindrance to the use of rubcrete is the reduction in compressive and tensile strength of concrete due to the presence of rubber. If these undesirable properties of rubcrete can be controlled, a new cementitious composite with better ductility, seismic performance and economy can be developed. A combination of rubber particles and steel fibre has the potential to reduce the undesirable effect of rubcrete. In this paper, the effect of rubber particles and steel fibre in the behaviour of two-span continuous deep beams is studied experimentally. Based on the results, optimum proportions of steel fibre and rubber particles for getting good ductile behaviour with less reduction in collapse load is found out.

Nutrient cycling in a RRIM 600 clone rubber plantation

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Murbach Marcos Roberto

2003-01-01

Full Text Available Few reports have been presented on nutrient cycling in rubber tree plantations (Hevea brasiliensis Muell. Arg.. This experiment was carried out to evaluate: the effect of K rates on the amount of nutrients transfered to the soil in a 13-year old Hevea brasilensis RRIM 600 clone plantation, nutrient retranslocation from the leaves before falling to the soil, and nutrient loss by dry rubber export. The experiment started in 1998 and potassium was applied at the rates of 0, 40, 80 and 160 kg ha-1 of K2O under the crowns of 40 rubber trees of each plot. Literfall collectors, five per plot, were randomly distributed within the plots under the trees. The accumulated literfall was collected monthly during one year. The coagulated rubber latex from each plot was weighed, and samples were analyzed for nutrient content. Increasing K fertilization rates also increased the K content in leaf literfall. Calcium and N were the most recycled leaf nutrients to the soil via litterfall. Potassium, followed by P were the nutrients with the highest retranslocation rates. Potassium was the most exported nutrient by the harvested rubber, and this amount was higher than that transfered to the soil by the leaf literfall.

Alexithymia Modulates the Experience of the Rubber Hand Illusion

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Delphine eGrynberg

2015-06-01

Full Text Available Alexithymia is associated with lower awareness of emotional and non-emotional internal bodily signals. However, evidence suggesting that alexithymia modulates body awareness at an external level is scarce. This study aimed to investigate whether alexithymia is associated with disrupted multisensory integration by using the rubber hand illusion task.Fifty healthy individuals completed the Toronto Alexithymia Scale and underwent the rubber hand illusion measure. In this measure, one watches a rubber hand being stroked synchronously or asynchronously with one’s own hand, which is hidden from view. Compared to the asynchronous stimulation, the synchronous stimulation results in the illusion that the rubber hand and the participant’s hand are closer together than they really are and that the rubber hand belongs to them. Results revealed that higher levels of alexithymia are associated with a lower ownership illusion. In conclusion, our findings demonstrate that high alexithymia scorers integrate two simultaneous sensory and proprioceptive events into a single experience (lower multisensory integration to a lesser extent than low alexithymia scorers. Higher susceptibility to the illusion in high alexithymia scorers may -indicate that alexithymia is associated with impaired multisensory integration and that this association results from an abnormal focus of one's own body.

EB-promoted recycling of waste tire rubber with polyolefins

International Nuclear Information System (INIS)

Mészáros, László; Bárány, Tamás; Czvikovszky, Tibor

2012-01-01

Despite the fact that more and more methods and solutions are used in the recycling of polymers, there are still some problems, especially in the recycling of cross-linked materials such as rubber. Usually the biggest problem is the lack of compatibility between the cross-linked rubber and the thermoplastic matrix. In this study we applied ground tire rubber (GTR) as recycled material. The GTR was embedded into polyethylene (PE) and polyethylene/ethylene-vinyl acetate copolymer (PE/EVA) matrices. In order to increase the compatibility of the components electron beam (EB) irradiation was applied. The results showed that the irradiation has a beneficial effect on the polymer–GTR interfacial connection. The EB treatment increased not only the tensile strength but also the elongation at break. The irradiation had also positive effect on the impact strength properties. - Highlights: ► In this study ground tire rubber was incorporated into polyethylene (LDPE) matrix. ► Compatibilizing effects of irradiation and ethylene-vinyl acetate were investigated. ► The samples were manufactured by twin-screw extrusion and injection molding. ► Both compatibilizing methods improved the rubber-like properties of the blends. ► This improvement was especially significant when they were applied together.

Effect of Rubber Nanoparticle Agglomeration on Properties of Thermoplastic Vulcanizates during Dynamic Vulcanization

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Hanguang Wu

2016-04-01

Full Text Available We previously reported that the dispersed rubber microparticles in ethylene-propylene-diene monomer (EPDM/polypropylene (PP thermoplastic vulcanizates (TPVs are actually agglomerates of rubber nanoparticles. In this study, based on this new understanding of the microstructure of TPV, we further revealed the microstructure-properties relationship of EPDM/PP TPV during dynamic vulcanization, especially the effect of the size of rubber nanoparticle agglomerates (dn, the thicknesses of PP ligaments (IDpoly and the rubber network on the properties of EPDM/PP TPV. We were able to simultaneously obtain a high tensile strength, elongation at break, elastic modulus, and elasticity for the EPDM/PP TPV by the achievement of a smaller dn, a thinner IDpoly and a denser rubber network. Interestingly, the effect of dn and IDpoly on the elastic modulus of EPDM/PP TPV composed of rubber nanoparticle agglomerates is different from that of EPDM/PP TPVs composed of rubber microparticles reported previously. The deformation behavior of the TPVs during stretching was studied to understand the mechanism for the achievement of good mechanical properties. Interestingly, the rubber nanoparticle agglomerates are oriented along the tensile direction during stretching. The TPV samples with smaller and more numerous rubber nanoparticle agglomerates can slow down the development of voids and cracks more effectively, thus leading to increase in tensile strength and elongation at break of the EPDM/PP TPV.

Case study of rutting performance of HMA modified with waste rubber powder

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G.H. Shafabakhsh

2014-01-01

Full Text Available Low resistance against dynamic loads and short service life of pavement are the most significant problems in the conservation and maintenance of roads, to the extent that, annually enormous costs are spent in order to improve capabilities of road services in the country. Research shows that the use of some wastes such as waste rubber powder in asphalt mixtures not only increase its serves life but also cause to reduce production costs; furthermore, recycling the crumb rubber has also considerably environmental benefits environmental benefits such as reduced need for landfill, less atmospheric pollution from burning. In this paper, the effect of adding waste rubber powder on the rutting performance of asphalt mixtures has been studied. In order to compare the performance of rubberized asphalt mixtures and conventional asphalt, wheel track test has been used. The results of this study show that the use of rubber powder caused a significant decrease in the rate of rutting depth of rubber asphalt mixtures compared to control samples.

Rubber friction: The contribution from the area of real contact.

Science.gov (United States)

Tiwari, A; Miyashita, N; Espallargas, N; Persson, B N J

2018-06-14

There are two contributions to the friction force when a rubber block is sliding on a hard and rough substrate surface, namely, a contribution F ad = τ f A from the area of real contact A and a viscoelastic contribution F visc from the pulsating forces exerted by the substrate asperities on the rubber block. Here we present experimental results obtained at different sliding speeds and temperatures, and we show that the temperature dependency of the shear stress τ f , for temperatures above the rubber glass transition temperature T g , is weaker than that of the bulk viscoelastic modulus. The physical origin of τ f for T > T g is discussed, and we propose that its temperature dependency is determined by the rubber molecule segment mobility at the sliding interface, which is higher than in the bulk because of increased free-volume effect due to the short-wavelength surface roughness. This is consistent with the often observed reduction in the glass transition temperature in nanometer-thick surface layers of glassy polymers. For temperatures T contact regions and the contact area is determined by the rubber penetration hardness. For this case, we propose that the frictional shear stress is due to slip at the interface between the rubber and a transfer film adsorbed on the concrete surface.

Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

Energy Technology Data Exchange (ETDEWEB)

Xu, Tiwen [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Jia, Zhixin, E-mail: zxjia@scut.edu.cn [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Yuanfang; Jia, Demin [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Peng, Zheng [Agricultural Product Processing Research Institute, Chinese Academy of Tropical Agriculture Sciences, Zhanjiang 524001 (China)

2015-02-15

Highlights: • Substantiate the ring open reaction between Si-OH of silica and epoxy groups of ENR. • ENR can act as a bridge between NR and silica to enhance the interfacial interaction. • As a modifier, ENR gets the potential to be used in the tread of green tire for improving the wet skid resistance apparently. - Abstract: The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress–strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

Preparation and Characterisation of Crosslinked Natural Rubber (SMR CV 60 and Epoxidised Natural Rubber (ENR-50 Blends

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M. SASITARAN

2018-04-01

Full Text Available In this sudy, the influenceof di(tert-butylperoxyisopropylbenzene (DTBPIB on the properties of natural rubber (NR blend with epoxidized natural rubber (ENR was determined. Fourier transform infrared spectroscopy with attenuated total refletance analysis and gel content confired crosslinking occurred in the rubber blends in the presence of peroxide DTBPIB percentage. Studies including tensile properties, dynamic mechanical properties, thermogravimetric analysis (TGA and water absorptivity showed the changes in properties of the crosslinked NR/ENR blends. Tensile properties analysis disclosed the improvements in the modulus at 300% elongation and tensile stength with increasing NR ratios. Dynamic mechanical analysis revealed the blends to be incompatible and immiscible, with ENR showing a more viscous behaviour compared to the polymer blends. Thermal properties improved by blending NR with ENR as the onset temperature of NR/ENR: 50/50 was higher than pure NR by approximately 10oC and ENR by approximately 2oC. Water absorptivity experiment revealed a two-fold reduction in the presence of crosslinking for all blend ratios.

Study on the Secant Segmentation Algorithm of Rubber Tree

Science.gov (United States)

Li, Shute; Zhang, Jie; Zhang, Jian; Sun, Liang; Liu, Yongna

2018-04-01

Natural rubber is one of the most important materials in the national defense and industry, and the tapping panel dryness (TPD) of the rubber tree is one of the most serious diseases that affect the production of rubber. Although considerable progress has been made in the more than 100 years of research on the TPD, there are still many areas to be improved. At present, the method of artificial observation is widely used to identify TPD, but the diversity of rubber tree secant symptoms leads to the inaccurate judgement of the level of TPD. In this paper, image processing technology is used to separate the secant and latex, so that we can get rid of the interference factors, get the exact secant and latex binary image. By calculating the area ratio of the corresponding binary images, the grade of TPD can be classified accurately. and can also provide an objective basis for the accurate identification of the tapping panel dryness (TPD) level.

Nanostructured magnesium oxide as cure activator for polychloroprene rubber.

Science.gov (United States)

Kar, Sritama; Bhowmick, Anil K

2009-05-01

The aim of this research was to synthesize magnesium oxide nanoparticles and to use them as cure activator for polychloroprene rubber (CR). The effects of counterions of magnesium salts on the homogeneous phase precipitation reaction to control size, monodispersity, crystallinity, and morphology of Mg(OH)2 nanoparticles were also investigated. Magnesium oxide nanoparticles were synthesized by optimizing the calcination temperature of Mg(OH)2 nanoparticles. Finally, the MgO nanoparticles were dispersed in polychloroprene rubber (CR) solution along with zinc oxide (ZnO) powder. The influence of MgO nanoparticles on the mechanical, dynamic mechanical and thermal properties of the resulting nanocomposites was quantified. The modulus and strength of ZnO-cured polychloroprene rubber with 4% MgO nanoparticles appeared to be superior to those with ZnO particles or ZnO with rubber grade MgO particles. These composites were further characterized by transmission electron microscopy and infrared spectroscopy in order to understand the morphology of the resulting system and the load transfer mechanism.

Piezoelectric ribbons printed onto rubber for flexible energy conversion.

Science.gov (United States)

Qi, Yi; Jafferis, Noah T; Lyons, Kenneth; Lee, Christine M; Ahmad, Habib; McAlpine, Michael C

2010-02-10

The development of a method for integrating highly efficient energy conversion materials onto stretchable, biocompatible rubbers could yield breakthroughs in implantable or wearable energy harvesting systems. Being electromechanically coupled, piezoelectric crystals represent a particularly interesting subset of smart materials that function as sensors/actuators, bioMEMS devices, and energy converters. Yet, the crystallization of these materials generally requires high temperatures for maximally efficient performance, rendering them incompatible with temperature-sensitive plastics and rubbers. Here, we overcome these limitations by presenting a scalable and parallel process for transferring crystalline piezoelectric nanothick ribbons of lead zirconate titanate from host substrates onto flexible rubbers over macroscopic areas. Fundamental characterization of the ribbons by piezo-force microscopy indicates that their electromechanical energy conversion metrics are among the highest reported on a flexible medium. The excellent performance of the piezo-ribbon assemblies coupled with stretchable, biocompatible rubber may enable a host of exciting avenues in fundamental research and novel applications.

Physical, mechanical and thermal properties of Crushed Sand Concrete containing Rubber Waste

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Mohamed Guendouz

2018-01-01

Full Text Available Over the past twenty years, the rubber wastes are an important part of municipal solid waste. This work focuses on the recycling of rubber waste, specifically rubber waste of used shoes discharged into the nature and added in the mass of crushed sand concrete with percentage (10%, 20%, 30% and 40%. The physical (workability, fresh density, mechanical (compressive and flexural strength and thermal (thermal conductivity of different crushed sand concrete made are analyzed and compared to the respective controls. The use of rubber waste in crushed sand concrete contributes to reduce the bulk density and performance of sand concrete. Nevertheless, the use of rubber aggregate leads to a significant reduction in thermal conductivity, which improves the thermal insulation of crushed sand concrete.

Credit Booms and Busts in Emerging Markets: The Role of Bank Governance and Risk Management

OpenAIRE

Brown, Martin; Andries, Alin Marius

2014-01-01

This paper investigates to what extent risk management and corporate governance mitigate the involvement of banks in credit boom and bust cycles. Using a unique, hand-collected dataset on 156 banks from Central and Eastern Europe during 2005-2012, we assess whether banks with stronger risk management and corporate governance display more moderate credit growth in the pre-crisis credit boom as well as a smaller credit contraction and fewer credit losses in the crisis period. With respect to ba...

Preparation of irradiated natural rubber latex-styrene copolymer for electrical gloves

International Nuclear Information System (INIS)

Made Sumarti Kardha

2010-01-01

Research on irradiated natural rubber latex-styrene copolymer to prepare electrical glove have been done. Vulcanization of natural rubber latex (NRL) was done by mixing 2 phr (per hundred of rubber) of normal butyl acrylate (n-BA) emulsion then irradiated with ã-ray "6"0Co at the dose of 30 kGy producing irradiated natural rubber latex (INRL). Natural rubber latex-styrene copolymers (SC) were prepared by mixing NRL and styrene monomer at styrene concentrations of 50 phr, 75 phr, 100 phr, 500 phr and irradiated at the doses of 15 kGy, 30 kGy and 45 kGy, then characterized their latex and film properties to obtain optimum SC of SC50. This optimum SC, SC50 then mixed with IRNL at the weight ratio of 0/100, 30/70, 50/50, 70/30 and 100/0, to produce irradiated natural rubber latex-styrene copolymer. The properties of copolymer rubber films made by dipping process i.e., % conversion, total solid content, latex viscosity, tensile strength, modulus 300 %, elongation at break, electrical resistance and dielectric constant were then characterized. Characterization result showed that (INRL-SC50) with 50/50 ratio irradiated at the dose of 30 kGy, have % conversion of 80.93 %, electrical resistivity of 1.73 x 10"1"4 Ohm cm and dielectric constant of 2.76 which fulfill the requirement as material for electrical gloves. (author)

Low-Boom and Low-Drag Optimization of the Twin Engine Version of Silent Supersonic Business Jet

Science.gov (United States)

Sato, Koma; Kumano, Takayasu; Yonezawa, Masahito; Yamashita, Hiroshi; Jeong, Shinkyu; Obayashi, Shigeru

Multi-Objective Optimization has been applied to a design problem of the twin engine concept for Silent Supersonic Business Jet (SSBJ). This problem aims to find main wing, body, tail wing and engine nacelle configurations, which can minimize both sonic boom and drag in a supersonic cruising flight. The multi-objective genetic algorithm (MOGA) coupled with the Kriging model has been used to globally and effectively search for optimal design candidates in the multi-objective problem. The drag and the sonic boom have been evaluated by the computational fluid dynamics (CFD) simulation and the waveform parameter method. As a result, the present optimization has successfully obtained low-boom and low-drag design candidates, which are better than the baseline design by more than 40% regarding each performance. Moreover, the structure of design space has been visualized by the self-organizing map (SOM).

Influence the Rubber Seed Type and Altitude on Characteristic of Seed, Oil and Biodiesel

OpenAIRE

Salni Salni; Poedji Loekitowati Hariani; Hanifa Marisa Hanifa

2017-01-01

This research studies the influence of the type of rubber seed that is superior and local, altitude plant in South Sumatra province to the characteristic of seed, oil and biodiesel (methyl ester). Rubber plants planted from local rubber seed by seeds seedlings and superior rubber seed by selected clones. In the study, rubber plants planted at a different altitude, namely in Banyuasin district (18 m above sea level), Prabumulih District (176 m above sea level) and Lahat District (627 m above s...

From rubber tree homeland to rubber tree plantation: Jacques Huber and his studies on the culture of heveas in the East (1911-1912

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Anna Raquel de Matos Castro

2009-12-01

Full Text Available The paper deals with the trip of the Swiss botanist Jacques Huber (1867-1914 to the main eastern rubber producing countries between 1911 and 1912. This trip was intended to develop studies on the cultivation of Hevea brasiliensis in that region. Huber was commissioned with the task by the State of Pará governor João Coelho, who wanted to find solutions to the downfall of the regional economy. The economy of Amazonia was primarily based on rubber extractivism and was seriously endangered due the market controlled by England from eastern plantations. Back to Brazil, Huber published a report with information about the society, economy and environment where the rubber trees were cultivated. The report compiles scientific observations and the topics that motivated the regional elites in that context. In addition to the brief analyses of the report, photographs took by Huber in the East of rubber trees plantations, tree tapping and local workers are published.

Study of a 30-M Boom For Solar Sail-Craft: Model Extendibility and Control Strategy

Science.gov (United States)

Keel, Leehyun

2005-01-01

Space travel propelled by solar sails is motivated by the fact that the momentum exchange that occurs when photons are reflected and/or absorbed by a large solar sail generates a small but constant acceleration. This acceleration can induce a constant thrust in very large sails that is sufficient to maintain a polar observing satellite in a constant position relative to the Sun or Earth. For long distance propulsion, square sails (with side length greater than 150 meters) can reach Jupiter in two years and Pluto in less than ten years. Converting such design concepts to real-world systems will require accurate analytical models and model parameters. This requires extensive structural dynamics tests. However, the low mass and high flexibility of large and light weight structures such as solar sails makes them unsuitable for ground testing. As a result, validating analytical models is an extremely difficult problem. On the other hand, a fundamental question can be asked. That is whether an analytical model that represents a small-scale version of a solar-sail boom can be extended to much larger versions of the same boom. To answer this question, we considered a long deployable boom that will be used to support the solar sails of the sail-craft. The length of fully deployed booms of the actual solar sail-craft will exceed 100 meters. However, the test-bed we used in our study is a 30 meter retractable boom at MSFC. We first develop analytical models based on Lagrange s equations and the standard Euler-Bernoulli beam. Then the response of the models will be compared with test data of the 30 meter boom at various deployed lengths. For this stage of study, our analysis was limited to experimental data obtained at 12ft and 18ft deployment lengths. The comparison results are positive but speculative. To observe properly validate the analytic model, experiments at longer deployment lengths, up to the full 30 meter, have been requested. We expect the study to answer the

O SENTIMENTO DO PACIENTE FRENTE AO CANCELAMENTO DA CIRURGIA

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Fernanda Aparecida Silva

2017-02-01

Full Text Available O paciente, frente ao cancelamento da cirurgia, pode apresentar sentimentos: tristeza, agressividade, revolta, e perder a confiança da equipe cirúrgica. Objetivo: Identificar o sentimento do paciente internado frente ao cancelamento de sua cirurgia. Método: Pesquisa descritiva e quali-quantitativa. A coleta de dados ocorreu após aprovação do Comitê de Ética sob o n0 45/11, com 20 pacientes internados em um hospital do vale do Paraíba paulista. Resultados: Predominou:80% do sexo masculino, 30% de 51 a 60 anos. Principal causa cancelamento: 35% material, 10% vaga na Unidade de Terapia Intensiva (UTI, e 55% médicos, exames, vaga no centro cirúrgico ou infecção. Os sentimentos foram agrupados em quatro categorias: tristeza; estresse; conformismo e sentimentos variados.Conclusão: O perfil predominante dos pacientes foi de homens, entre 51 a 60 anos. A principal causa do cancelamento foi a falta de material; o sentimento de maior destaque foi a tristeza.

Factors affecting Thai rubber farmer production and marketing in the western province of Kanchanaburi

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Narisa Thongtrai

2016-04-01

Full Text Available This research aimed to study the factors affecting the production and marketing of rubber farmers in the western Thai province of Kanchanaburi. The sample group included 30 farmers involved in rubber production. From the questionnaire and statistical analysis by SPSS, 15 observed variables were determined to be factors affecting the production and marketing of rubber farmers. The conclusion from the researchers determined that 1 The area planted is not appropriate and is still expanding plantations without any control was found that the rubber plantations are expanding at high plains area flooding. 2 Farmers of rubber technology farmers are not valid and do not conform to the instructions of the Rubber Research Institute study found that the cause is the opportunity to access technology and lack of knowledge regarding the management, production, and marketing. 3 Use rubber tree tapping of the system to high frequency screaming systems correctly. Does not comply with the instructions of the Rubber Research Institute found that of rubber farmers and farmers opening tapped the tire rubber accelerator before opening a huge size tapped that affect productivity and the income of farmers depressed farmers. 4 Problems with the labor of producing rubber of the household. It was found that labor households in the production system are lower 5 Farmers of Thailand are not yet aware of the concept of livelihood along the sufficiency economy as should farmers be life according to the way of life that is not adjusted to prepare 6 Group integration it was found that is not yet strong.

Frentes de ondas (wavefronts e limites da visão humana Parte 1: fundamentos

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Jankov Mirko

2002-01-01

Full Text Available A luz se propaga uniformemente a partir de um ponto luminoso na mesma velocidade em todas as direções. Sua posição em cada determinado momento é uma esfera formada juntando-se todos os pontos em uma mesma fase e tendo como centro a sua própria fonte. Tais superfícies esféricas imaginárias chamam-se frentes de luz ou frentes de ondas. Há três fatores limitadores de detalhes mais finos para o olho humano: óptico (por causa da dispersão, difração, aberração cromática e aberração monocrom��tica, retínico e neural (limitação máxima de acuidade visual de aproximadamente 2,0 ou 20/10.Um sistema de equações matemáticas, polinômios de Zernike, pode definir superfícies geométricas para descrever aberrações ópticas monocromáticas, tanto as de baixa ordem ('prisma', 'esfera' e 'astigmatismo', quanto às de alta ordem ('coma', 'aberração esférica' e outros. Medida das aberrações ópticas nos dá informação sobre o desempenho total de todos os elementos ópticos do olho em conjunto. Dois sistemas descritos aqui, o aberrômetro baseado no princípio de Tscherning e o originado do sensor Hartmann-Shack, têm a mesma lógica: comparar a posição atual das frentes de onda com a ideal, calcular matematicamente qual é a superfície geométrica que descreve essa discrepância e representá-la em termos de polinômios de Zernike. A topografia corneana computadorizada também pode, com "software" adequado, descrever as frentes de ondas definidas por irregularidades corneanas com polinômios de Zernike, porém tal caracterização representa somente a superfície anterior da córnea. Em conclusão, a tecnologia de frentes de ondas oferece nova maneira de quantificar e classificar os erros de imagem óptica do olho humano. O próximo artigo abordará as peculiaridades da análise de frentes de ondas, bem como algumas aplicações clínicas e cirúrgicas no dia-a-dia da prática oftalmológica.

Pembuatan Alur Pelayaran dalam Rencana Pelabuhan Marina Pantai Boom, Banyuwangi

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Muhammad Didi Darmawan

2017-01-01

Full Text Available Pantai Boom merupakan pantai yang ada di Kabupaten Banyuwangi. Pantai ini terletak di Kelurahan Kampung Mandar, Kecamatan Banyuwangi, Banyuwangi, Jawa Timur. Pantai tersebut rencananya akan dibangun pelabuhan marina. Pelabuhan harus dilengkapi dengan beberapa fasilitas untuk mendukung rencana tersebut seperti salah satunya adalah alur pelayaran. Untuk membuat alur pelayaran diperlukan penelitian mengenai pasang surut, topografi dasar laut, serta jenis kapal yang melintas untuk memastikan kapal yang berlayar aman dari kemungkinan kecelakaan. Penelitian ini menggunakan data hasil pemeruman, data pasang surut yang diperoleh dari pengamatan langsung, serta berbagai jenis kapal yacht. Hasil dari penelitian ini didapatkan bahwa rencana dermaga sebaiknya dibangun 60 meter menjorok ke arah laut dengan panjang dermaga 25 meter. Dalam keadaan air rendah terendah (LLWL, ketiga jenis kapal yang ditentukan dapat merapat ke rencana Dermaga Pelabuhan Marina Pantai Boom, Banyuwangi. Daerah yang tidak bisa dilewati pada saat LLWL, pada saat MSL daerah tersebut sudah dapat dilewati oleh ketiga jenis kapal tersebut. Pada keadaan muka air tinggi tertinggi (HHWL, Kapal Yacht Class 8 dan 6 dapat melewati sebagian perairan sungai Pantai Boom.         Waktu yang tidak tepat untuk melakukan pelayaran pada saat LLWL dari alur pelayaran yang telah dibuat yaitu antara pukul 04:00 – 06:00 WIB pada saat bulan November 2015-Februari 2016 dan pukul 16:00-18:00 pada saat bulan Juni-Agustus 2016. Sedangkan Waktu yang tepat untuk melakukan pelayaran pada saat HHWL yaitu antara pukul 20:00–23:00 WIB pada saat bulan Desember 2015- Maret 2016 dan pukul 8:00-11:00 pada saat bulan Juni-September 2016.

Advantages of Concrete Mixing with Tyre Rubber

OpenAIRE

Mazyad Al-Fadhli *

2017-01-01

Strong waste administration is one of the major natural concerns everywhere throughout the world. Tire-rubber particles made out of tire chips, piece elastic, and a mix of tire chips and scrap elastic, where utilized to supplant mineral totals in cement. These particles were utilized to supplant 10% , 15% , 20%, and 25% of the aggregate mineral totals volume in cement.Using rubber aggregates in such applications can help to prevent pollution and overcome the problem of storing used tyres. Adv...

The use of styrene-butadiene rubber waste as a potential filler in nitrile rubber: order of addition and size of waste particles

Directory of Open Access Journals (Sweden)

D. A. Baeta

2009-03-01

Full Text Available Styrene-butadiene rubber (SBR has large applications in the shoe industry, especially as expanded sheets used to produce insoles and inner soles. According to TG analysis, the rubber content in SBR residues (SBR-r was found to be around 26-wt%. Based on that data, a cost-effective technique for the reuse of SBR-r in Nitrile rubber (NBR was developed. Later, the effect of SBR-r on the cure behavior, mechanical performance, swelling, and crosslink density of reused rubber was investigated, with more emphasis placed on the effect of both particle size and loading of waste filler. Cure characteristics such as optimum cure time and scorch time were then reduced by the increasing amount of SBR-r filler. Owing to the reinforced nature of the largest particle size SBR-r, the best results for the mechanical properties of NBR were those in which SBR-r was added at the end of the cure process. The study has thus shown that SBR residue (SBR-r can be used as an economical alternative filler in NBR.

Studies of chemical interactions between chlorosulphonated polyethylene and nit rile rubber

Directory of Open Access Journals (Sweden)

Marković Gordana

2005-01-01

Full Text Available Highly polar rubbers interact with each other through their active functional groups via condensation or substitution reactions at high temperature. Chlorosulphonated polyethylene (CSM rubber is a highly reactive rubber, the reactivity of with is due to the -SO2CI groups. When CSM reacts with nit rile rubber (NBR, a chemical reaction takes place between the two rubbers at high temperature. Fourier transform infrared (FTIR studies support that CSM/NBR (50/50 w/w isothermally induces a self cross-linking blend, when cross-linking takes place via the acrylonitrile groups of NBR and the SO2CI groups or the insitu generated allyl chloride moieties of CSM. There is a loss of some -CN groups during cross-linking. This may be due to an attack on the -CN groups by HCI (produced during the heating of CSM in the presence of inherent moisture in the polymers. Amid type of linkage is formed due to cross-linking.

Study on cord/rubber interface at elevated temperatures by H-pull test method

Science.gov (United States)

Jamshidi, M.; Afshar, F.; Mohammadi, N.; Pourmahdian, S.

2005-08-01

Cords are used as reinforcing materials in rubber compounds. To increase cord/rubber interfacial adhesion, they are coated by an adhesive (usually based on resorcinol-formaldehyde-latex). These composites are used in many sectors such as tire and belt industries. Cord/rubber adhesion strength is an important aspect to determine the durability of system. Due to temperature increase during running tires, the adhesion energy becomes different from initial one. To study cord/rubber interface at elevated temperatures, H-adhesion test method was used. H-pull test is a simple method for adhesion evaluation at ambient temperature, so it is usually used for material quality control. In this research, cord/rubber systems were vulcanized at different temperatures and H-adhesion of samples were evaluated at elevated temperatures. Also cord/rubber interface was studied by ATR analyze to determine interfacial interactions kind.

Experience of rubber band ligation for haemorrhoidal disease

International Nuclear Information System (INIS)

Hadi, A.; Aman, Z.; Anwar, F.; Khan, M.; Iqbal, Z.

2011-01-01

Objectives: To assess symptomatic relief in haemorrhoidal disease using rubber band ligation. Settings and duration: Surgical unit, Hayatabad Medical Complex, Peshawar from July 2007 to June 2009. Patients and Methods: All patients presenting with rectal bleeding or prolapse underwent proto copy to determine the cause of bleeding. Only patients with first, second and third degree haemorrhoids (bleeding and prolapse) were selected for the study and they underwent rubber band ligation in two sessions, 6 weeks apart. Patients were followed in the OPD at 3 months and one year when their subjective and objective symptoms were noted followed by rectal examination and proctoscopy. Therapeutic response was assessed by symptomatic improvement in bleeding and prolapse of hemorrhoids and any complications. Results: A total of 105 patients underwent rubber band ligation. There were 65(62%) males and 40(38%) females with a male to female ratio of 1.6:1. Age of the patients ranged from 21-65 years (+- 2.4 SD). Twenty three (21.9%) patients had first degree, 50(47.6%) had second degree and 32(30.5%) had third degree haemorrhoids. Forty-eight patients (45.7%) presented with degree, 50(47.6%) had second prolapse, 33(31.4%) had both bleeding and prolapse and 23(21.9%) had bleeding only. At 3 months of follow up rubber band ligation cured 76(72.4%) patients, improved 13(12.4%) and failed in 7(6.7%) patients. At one year follow up, recurrence of bleeding and prolapse occurred in 16(15.2%) patients having third degree haemorrhoids. Overall success was third achieved in 89(84.8%) cases. Complications were seen in 20(19.1%) patients which were of mild to moderate nature and no serious/ life threatening complications were noted. Conclusion: Rubber band legislation is a rapid and safe procedure for testing first, second and and early third degree Conclusions: Rubber band ligation is a rapid and safe non operative procedure for treating first, second and third degree haemorrhoids on out

Influence of the surface treatment of tire rubber residues added in mortars

Directory of Open Access Journals (Sweden)

A. C. Marques

Full Text Available In this work it was evaluated the influence tire rubber addition in mortars in order to replace part of the sand (12% by volume. It was also intended to verify if the tire rubber treatment with NaOH saturated aqueous solution causes interference on the mechanical properties of the mixture. Compressive strength, splitting tensile strength, water absorption, modulus of elasticity, and flow test were made in specimens of 5cmx10cm and the tests were carried out to 7, 28, 56, 90, and 180 days. The results show reduction on mechanical properties values after addition of tire rubber and decrease of the workability. It was also observed that the tire rubber treatment does not cause any alteration on the results compared to the rubber without treatment.

Current-driven plasmonic boom instability in three-dimensional gated periodic ballistic nanostructures

Science.gov (United States)

Aizin, G. R.; Mikalopas, J.; Shur, M.

2016-05-01

An alternative approach of using a distributed transmission line analogy for solving transport equations for ballistic nanostructures is applied for solving the three-dimensional problem of electron transport in gated ballistic nanostructures with periodically changing width. The structures with varying width allow for modulation of the electron drift velocity while keeping the plasma velocity constant. We predict that in such structures biased by a constant current, a periodic modulation of the electron drift velocity due to the varying width results in the instability of the plasma waves if the electron drift velocity to plasma wave velocity ratio changes from below to above unity. The physics of such instability is similar to that of the sonic boom, but, in the periodically modulated structures, this analog of the sonic boom is repeated many times leading to a larger increment of the instability. The constant plasma velocity in the sections of different width leads to resonant excitation of the unstable plasma modes with varying bias current. This effect (that we refer to as the superplasmonic boom condition) results in a strong enhancement of the instability. The predicted instability involves the oscillating dipole charge carried by the plasma waves. The plasmons can be efficiently coupled to the terahertz electromagnetic radiation due to the periodic geometry of the gated structure. Our estimates show that the analyzed instability should enable powerful tunable terahertz electronic sources.

Load Absorption Characteristics of Tyre Production Waste Rubber for Playground Floor Systems

Directory of Open Access Journals (Sweden)

Abdul Ghani A.N.

2014-01-01

Full Text Available The floor surfaces where slides and swings are placed in parks and playrooms should be soft and thick to ensure that whenever a child falls, the surface can withstand the impact and minimize injuries to the child. Shredded tyres from waste tyres or waste rubber from tyre manufacturing could become beneficial as shock absorber material which can be used as a playground floor. In this study, rubber cubes and rubber pads with 5%, 8% and 10% SBR mixes were prepared for mechanical testing. Two types of floor design surfaces with and without plywood on the surface were assembled for the shock test. Gmax and HIC of this waste rubber flooring system were investigated using the compression test for the rubber cube and the drop test for the rubber pad. The criteria of general protection standards are 200g for optimum acceleration and 1000 for HIC. The Gmax and HIC results indicated that the material and system could ensure a safe fall from up to 1.0m height.

Fundamentals of the knowledge about chemical additives present in rubber gloves.

Science.gov (United States)

Oliveira, Hegles Rosa de; Alchorne, Alice de Oliveira de Avelar

2011-01-01

One of the most frequent causes of allergic contact dermatitis of occupational origin are rubber additives, which are present in Personal Protective Equipment (PPE). The most allergenic additives of natural and synthetic gloves are thiurams, carbamates and mercapto group. To investigate the state of knowledge about the chemical additives used in the manufacture of synthetic rubber gloves. This was a qualitative research study in which professionals working in the manufacture, research, prescription and commercialization of gloves answered an open questionnaire. 30 individuals were interviewed: 4 researchers in occupational medicine, 5 occupational physicians, 2 occupational safety technicians, a rubber workers' union physician, an occupational safety engineer, a pro duction engineer of rubber gloves, 4 importers of gloves, a manufacturer of gloves, 3 businessmen who sell PPE, 3 salesclerks working in stores that sell PPE, 2 businessmen who own stores that sell products for allergic individuals, and 3 dermatologists. Knowledge of the chemical composition of rubber gloves is scant. The labeling of gloves, with the description of their chemical composition, would facilitate choosing the best type of glove for each person. This low-cost action to businesses would be a gain from the standpoint of public health, with huge repercussions for users of rubber gloves.

Exposure to aged crumb rubber reduces survival time during a stress test in earthworms (Eisenia fetida).

Science.gov (United States)

Pochron, Sharon; Nikakis, Jacqueline; Illuzzi, Kyra; Baatz, Andrea; Demirciyan, Loriana; Dhillon, Amritjot; Gaylor, Thomas; Manganaro, Alexa; Maritato, Nicholas; Moawad, Michael; Singh, Rajwinder; Tucker, Clara; Vaughan, Daniel

2018-04-01

Solid waste management struggles with the sustainable disposal of used tires. One solution involves shredding used tires into crumb rubber and using the material as infill for artificial turf. However, crumb rubber contains hydrocarbons, organic compounds, and heavy metals, and it travels into the environment. Earthworms living in soil contaminated with virgin crumb rubber gained 14% less body weight than did earthworms living in uncontaminated soil, but the impact of aged crumb rubber on the earthworms is unknown. Since many athletic fields contain aged crumb rubber, we compared the body weight, survivorship, and longevity in heat and light stress for earthworms living in clean topsoil to those living in topsoil contaminated with aged crumb rubber. We also characterized levels of metals, nutrients, and micronutrients of both soil treatments and compared those to published values for soil contaminated with virgin crumb rubber. Consistent with earlier research, we found that contaminated soil did not inhibit microbial respiration rates. Aged crumb rubber, like new crumb rubber, had high levels of zinc. However, while exposure to aged crumb rubber did not reduce earthworm body weight as did exposure to new crumb rubber, exposure to aged crumb rubber reduced earthworm survival time during a stress test by a statistically significant 38 min (16.2%) relative to the survival time for worms that had lived in clean soil. Aged crumb rubber and new crumb rubber appear to pose similar toxic risks to earthworms. This study suggests an environmental cost associated with the current tire-recycling solution.

Boom clay pore water, home of a diverse microbial community

International Nuclear Information System (INIS)

Wouters, Katinka; Moors, Hugo; Leys, Natalie

2012-01-01

Document available in extended abstract form only. Boom Clay pore water (BCPW) has been studied in the framework of geological disposal of nuclear waste for over two decades, thereby mainly addressing its geochemical properties. A reference composition for synthetic clay water has been derived earlier by modelling and spatial calibration efforts, mainly based on interstitial water sampled from different layers within the Boom clay. However, since microbial activity is found in a range of extreme circumstances, the possibility of microbes interacting with future radioactive waste in a host formation like Boom Clay, cannot be ignored. In this respect, BCPW was sampled from different Boom Clay layers using the Morpheus piezometer and subsequently analysed by a complementary set of microbiological and molecular techniques, in search for overall shared and abundant microorganisms. Similar to the previous characterization of the 'average' BCPW chemical composition, the primary aim of this microbiological study is to determine a representative BCPW microbial community which can be used in laboratory studies. Secondly, the in situ activity and the metabolic properties of members of this community were addressed, aiming to assess their survival and proliferation chances in repository conditions. In a first approach, total microbial DNA of the community was extracted from the BCPW samples. This molecular approach allows a broad insight in the total microbial ecology of the BCPW samples. By polymerase chain reaction (PCR) on the highly conserved 16S rRNA genes in this DNA pool and subsequent sequencing and bio-informatics analysis, operational taxonomic units (OTUs) could be assigned to the microbial community. The bacterial community was found to be quite diverse, with OTUs belonging to 8 different phyla (Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Chlorobi, Spirochetes, Chloroflexi and Deinococcus-Thermus). These results provide an overall view of the

Boom clay pore water, home of a diverse microbial community

Energy Technology Data Exchange (ETDEWEB)

Wouters, Katinka; Moors, Hugo; Leys, Natalie [SCK.CEN, Environment, Health and Safety Institute, B-2400 Mol (Belgium)

2012-10-15

Document available in extended abstract form only. Boom Clay pore water (BCPW) has been studied in the framework of geological disposal of nuclear waste for over two decades, thereby mainly addressing its geochemical properties. A reference composition for synthetic clay water has been derived earlier by modelling and spatial calibration efforts, mainly based on interstitial water sampled from different layers within the Boom clay. However, since microbial activity is found in a range of extreme circumstances, the possibility of microbes interacting with future radioactive waste in a host formation like Boom Clay, cannot be ignored. In this respect, BCPW was sampled from different Boom Clay layers using the Morpheus piezometer and subsequently analysed by a complementary set of microbiological and molecular techniques, in search for overall shared and abundant microorganisms. Similar to the previous characterization of the 'average' BCPW chemical composition, the primary aim of this microbiological study is to determine a representative BCPW microbial community which can be used in laboratory studies. Secondly, the in situ activity and the metabolic properties of members of this community were addressed, aiming to assess their survival and proliferation chances in repository conditions. In a first approach, total microbial DNA of the community was extracted from the BCPW samples. This molecular approach allows a broad insight in the total microbial ecology of the BCPW samples. By polymerase chain reaction (PCR) on the highly conserved 16S rRNA genes in this DNA pool and subsequent sequencing and bio-informatics analysis, operational taxonomic units (OTUs) could be assigned to the microbial community. The bacterial community was found to be quite diverse, with OTUs belonging to 8 different phyla (Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Chlorobi, Spirochetes, Chloroflexi and Deinococcus-Thermus). These results provide an overall view of the

Performance of carbon fiber reinforced rubber composite armour against shaped charge jet penetration

OpenAIRE

Yue Lian-yong; Li Wei; Zu Xu-dong; Huang Zheng-xiang; Gao Zhen-yu

2016-01-01

Natural rubber is reinforced with carbon fiber; the protective performances of the carbonfiber reinforced rubber composite armour to shaped charge jet have been studied based on the depth of penetration experiments. The craters on the witness blocks, the nature rubber based composite plates’ deformation and the Scanning Electron Microscopy for the hybrid fiber reinforced rubber plate also is analyzed. The results showed that the composite armour can affect the stability of the jet and made pa...

Supply of Rubber Wood Log in Malaysia

OpenAIRE

Noraida, A. W.; Abdul-Rahim, A. S.

2014-01-01

Issue on shortage of raw material for wood processing solved by discovery of rubber wood log as one of the substitutes the natural log. This paper examines the supply of rubber wood log in Malaysia. We employ ARDL Bound Approach Test and time series data from 1980 to 2010 which represented the whole Malaysia are used to achieve the established objectives. The result shown, in the long run harvested area and wages have 1% and 10% significant level respectively. While in the short run, there wa...

Simulation and controller design for an agricultural sprayer boom leveling system

KAUST Repository

Sun, Jian; Miao, Yubin

2011-01-01

According to the agricultural precision requirements, the distance from sprayer nozzles to the corps should be kept between 50 cm to 70 cm. The sprayer boom also needs to be kept parallel to the field during the operation process. Thus we can

Potential of scrap tire rubber as lightweight aggregate in flowable fill.

Science.gov (United States)

Pierce, C E; Blackwell, M C

2003-01-01

Flowable fill is a self-leveling and self-compacting material that is rapidly gaining acceptance and application in construction, particularly in transportation and utility earthworks. When mixed with concrete sand, standard flowable fill produces a mass density ranging from 1.8 to 2.3 g/cm(3) (115-145 pcf). Scrap tires can be granulated to produce crumb rubber, which has a granular texture and ranges in size from very fine powder to coarse sand-sized particles. Due to its low specific gravity, crumb rubber can be considered a lightweight aggregate. This paper describes an experimental study on replacing sand with crumb rubber in flowable fill to produce a lightweight material. To assess the technical feasibility of using crumb rubber, the fluid- and hardened-state properties of nine flowable fill mixtures were measured. Mixture proportions were varied to investigate the effects of water-to-cement ratio and crumb rubber content on fill properties. Experimental results indicate that crumb rubber can be successfully used to produce a lightweight flowable fill (1.2-1.6 g/cm(3) [73-98 pcf]) with excavatable 28-day compressive strengths ranging from 269 to 1194 kPa (39-173 psi). Using a lightweight fill reduces the applied stress on underlying soils, thereby reducing the potential for bearing capacity failure and minimizing soil settlement. Based on these results, a crumb rubber-based flowable fill can be used in a substantial number of construction applications, such as bridge abutment fills, trench fills, and foundation support fills.

Pemanfaatan Silika Abu Sekam Padi sebagai Bahan Pengisi Rubber Membrane Filter Press untuk Memisahkan Minyak Inti Sawit

OpenAIRE

Nasruddin

2012-01-01

This research was aimed to obtain rubber membrane filter press (RMFP) from natural rubber (NR) as well as synthetic rubber (chloroprene rubber and nytrike butadiene rubber). The research method was done my vulcanizing natural rubber, synthetic rubber, and filler to shape RMFP. Research formulation was done with 8 units of experiments using variations of mixers that have been pre-determined. The examination to the RMFP was done with ASTM test methods that cover parameters such as viscometer mo...

Mechanical properties of irradiated rubber-blends