WorldWideScience

Sample records for rubber boom frentes

  1. Booming Sand Dunes

    Science.gov (United States)

    Vriend, Nathalie

    "Booming" sand dunes are able to produce low-frequency sound that resembles a pure note from a music instrument. The sound has a dominant audible frequency (70-105 Hz) and several higher harmonics and may be heard from far distances away. A natural or induced avalanche from a slip face of the booming dune triggers the emission that may last for several minutes. There are various references in travel literature to the phenomenon, but to date no scientific explanation covered all field observations. This thesis introduces a new physical model that describes the phenomenon of booming dunes. The waveguide model explains the selection of the booming frequency and the amplification of the sound in terms of constructive interference in a confined geometry. The frequency of the booming is a direct function of the dimensions and velocities in the waveguide. The higher harmonics are related to the higher modes of propagation in the waveguide. The experimental validation includes quantitative field research at the booming dunes of the Mojave Desert and Death Valley National Park. Microphone and geophone recordings of the acoustic and seismic emission show a variation of booming frequency in space and time. The analysis of the sensor data quantifies wave propagation characteristics such as speed, dispersion, and nonlinear effects and allows the distinction between the source mechanism of the booming and the booming itself. The migration of sand dunes results from a complicated interplay between dune building, wind regime, and precipitation. The morphological and morphodynamical characteristics of two field locations are analyzed with various geophysical techniques. Ground-penetrating radar images the subsurface structure of the dunes and reveal a natural, internal layering that is directly related to the history of dune migration. The seismic velocity increases abruptly with depth and gradually increases with downhill position due to compaction. Sand sampling shows local

  2. 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…

  3. Beyond the Boom

    Institute of Scientific and Technical Information of China (English)

    ANDY XIE

    2006-01-01

    @@ Annual GDP growth has averaged 10 percent in China in the past three years and 8 percent in India. During the same period,the global economy has enjoyed the biggest boom in decades,averaging 4.5 percent growth a year.

  4. Biobased products from rubber, jatropha and sunflower oil

    NARCIS (Netherlands)

    Bin Abu Ghazali, Yusuf

    2015-01-01

    In dit proefschrift wordt onderzoek beschreven naar het identificeren van interessante producten uit de zaden van de rubber boom (Hevea brasiliensis). Deze zaden worden momenteel niet gebruikt en in vele rubberplantages gezien als afval. De zaden bestaan uit een harde schil (39 wt%) en een kern (61

  5. 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.......Internet radio is one of the growth areas of the Internet but, as this article will show, is fraught with difficulties and frustration for both the modestly-funded broadcaster (bitcaster) and the listener. The article will illustrate some of these problems by means of a short case study...

  6. Boom Booom Net Radio

    DEFF Research Database (Denmark)

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

    1999-01-01

    Internet radio is one of the growth areas of the Internet but, as this article will show, is fraught with difficulties and frustration for both the modestly-funded broadcaster (bitcaster) and the listener. The article will illustrate some of these problems by means of a short case study of an exi......Internet radio is one of the growth areas of the Internet but, as this article will show, is fraught with difficulties and frustration for both the modestly-funded broadcaster (bitcaster) and the listener. The article will illustrate some of these problems by means of a short case study...... 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....

  7. Animation of boom failure processes

    Energy Technology Data Exchange (ETDEWEB)

    An, C. F.; Brown, H. M.; Goodman, R. H. [Imperial Oil Resources, Calgary, AB (Canada); Clavelle, E. J. [Calgary Univ., AB (Canada)

    1997-10-01

    Computer animations of oil boom failure mechanisms were discussed. The animations are useful in demonstrating the transient processes of boom failure. They consist of a series of images obtained from the graphical output of a computational fluid dynamics program, FLUENT, while the modeling is based on boom failure experiments carried out in flowing water channels. The animations can be viewed on a PC running under Windows `95. Three types of failures are presented, i. e. drainage failure, droplet entrainment and critical accumulation. 11 refs., 3 figs.

  8. FCC in Viking articulated boom

    Science.gov (United States)

    Hawkins, E. S.

    1972-01-01

    The application requirements and manufacturing techniques for the flat conductor cable used in the Viking Lander Articulated Boom Unit are described. The Viking Boom is a 3-axis device utilized to position a soil sampler and provide digging forces. This application imposed severe restrictions on size, weight, materials, and choice of manufacturing processes. The final cable assembly design resulted in a combination of collated cable and flexible circuits assembled by resistance welding techniques.

  9. Dynamic Analysis of The Intelligent Sprayer Boom

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Maagaard, Jørgen; Terp, Christian Istjord

    As part of the 3 year project “The intelligent Sprayer Boom”, financed by The Danish National Advanced Technology Foundation, the dynamics of the sprayer boom is to be analysed. In order to minimize the amount of herbicides used to kill the weeds in agriculture a new sprayer boom is being developed...... called “The intelligent sprayer boom”. For the sprayer boom the primary challenge is to hit the weeds with precision from a movable platform. Since the sprayer boom is mounted on a tractor the system will react to bumps in the field. The intelligent sprayer boom has an integrated camera technology...... system to work properly. At the University of Southern Denmark (SDU) a patent for an active damping system of the sprayer boom has been obtained. The subject of this paper is analysis of the dynamics of the Sprayer boom. The analysis is based on a Multibody Dynamics model of the sprayer boom and is made...

  10. Real Time Sonic Boom Display

    Science.gov (United States)

    Haering, Ed

    2014-01-01

    This presentation will provide general information about sonic boom mitigation technology to the public in order to supply information to potential partners and licensees. The technology is a combination of flight data, atmospheric data and terrain information implemented into a control room real time display for flight planning. This research is currently being performed and as such, any results and conclusions are ongoing.

  11. Realism Assessment of Sonic Boom Simulators

    Science.gov (United States)

    Sullivan, Brenda M.; Davies, Patrica; Hodgdon, Kthleen K.; Salamone, Joseph A., III; Pilon, Anthony

    2008-01-01

    Developments in small supersonic aircraft design are predicted to result in low-intensity sonic booms. Booms generated by current aircraft are similar to those that led to the ban on commercial supersonic fli ght over the US, so are unsuitable for parametric studies of psychoac oustic response to low-intensity booms. Therefore, simulators have be en used to study the impact of predicted low-intensity sonic booms. H owever, simulators have been criticized because, when simulating conv entional-level booms, the sounds were observed to be unrealistic by p eople experienced in listening to sonic booms. Thus, two studies were conducted to measure the perceived realism of three sonic boom simul ators. Experienced listeners rated the realism of conventional sonic boom signatures when played in these simulators. The effects on percei ved realism of factors such as duration of post-boom noise, exclusion of very low frequency components, inclusion of ground reflections, a nd type of simulator were examined. Duration of post-boom noise was f ound to have a strong effect on perceived realism, while type of simu lator had a weak effect. It was determined that post-boom noise had t o be at least 1.5 seconds long for the sound to be rated very realist ic. Loudness level did not affect realism for the range of sounds pla yed in the tests (80-93 dB ASEL).

  12. Natural rubber: leather composites

    OpenAIRE

    K. Ravichandran; N. Natchimuthu

    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 ...

  13. Oil Palm Boom and Land-Use Dynamics in Indonesia: The Role of Policies and Socioeconomic Factors

    OpenAIRE

    Gatto, Marcel; Wollni, Meike; Qaim, Matin

    2014-01-01

    We investigate land-use dynamics in Jambi, Sumatra, one of the hotspots of Indonesia' recent oil palm boom. Data from a structured village survey are used to analyze the role of socioeconomic and policy factors. Oil palm is partly grown on large plantations, but smallholders are also involved significantly. We find that, in spite of significant oil palm expansion, rubber remains the dominant crop. Most of the oil palm growth takes place on previous fallow and rubber land. Oil palm has not bee...

  14. Developments in rubber technology 2 synthetic rubbers

    CERN Document Server

    Lee, K

    1981-01-01

    This book is intended for those people who have a knowledge or understanding of rubber materials and processes but who wish to update their knowledge. It should be read in conjunction with Developments in Rubber Technology-l as that volume discussed developments in natural rubber and selected special purpose synthetic rubbers as well as additives. The authors have been selected for their expertise in each particular field and we, as editors, would like to express our appreciation to the individual authors and also to their companies. Such a book would be impossible to produce without such active cooperation as we have received. Volumes 1 and 2 of Developments in Rubber Technology cover rubbers which are processed and vulcanised in the traditional manner. It is appreciated that the omission of non-vulcanised rubber materials (the so­ called thermoplastic elastomers) will be unwelcome to many readers but it is intended, because of the size of the subject, to cover these materials in a subsequent volume. A.W. K...

  15. Mechanochemical modification of natural rubber

    Science.gov (United States)

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

    2016-11-01

    Thermomechanochemical changes of SVR 3L natural rubber after the treatment in the internal rubber mixer in the self-heating mode were studied. The effect of the molecular mass and content of the gel fraction of natural rubber is shown. Properties of rubber compounds and vulcanized rubber are presented. Taking into account modern requirements, a new alternative technology of obtaining halogenated elastomers based on the solid-phase (mechanochemical) halide modification is created. New halogen-containing natural rubber produced by this technology proves themselves in the conditions of rubber production. New fluorinated natural rubber produced by this technology proves themselves in the conditions of rubber production.

  16. 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.

  17. Experimental thermal mechanics of deployable boom structures

    Science.gov (United States)

    Predmore, R.

    1972-01-01

    An apparatus was developed for thermal distortion measurements on deployable boom structures. The calibration procedure and thermal static bending plus twist measurements are considered. The thermal mechanics test facility is described. A table is presented for several examples of spacecraft applications of thermal static distortion measurements on 3-m deployable booms.

  18. Dynamic Simulation of the Harvester Boom Cylinder

    Directory of Open Access Journals (Sweden)

    Rongfeng Shen

    2017-04-01

    Full Text Available Based on the complete dynamic calculation method, the layout, force, and strength of harvester boom cylinders were designed and calculated. Closed simulations for the determination of the dynamic responses of the harvester boom during luffing motion considering the cylinder drive system and luffing angle position control have been realized. Using the ADAMS mechanical system dynamics analysis software, six different arm poses were selected and simulated based on the cylinder as the analysis object. A flexible model of the harvester boom luffing motion has been established. The movement of the oil cylinder under different conditions were analyzed, and the main operation dimensions of the harvester boom and the force condition of the oil cylinder were obtained. The calculation results show that the dynamic responses of the boom are more sensitive to the luffing acceleration, in comparison with the luffing velocity. It is seen that this method is very effective and convenient for boom luffing simulation. It is also reasonable to see that the extension of the distance of the bottom of the boom is shortened by adjusting the initial state of the boom in the working process, which can also effectively reduce the workload of the boom—thus improving the mechanical efficiency.

  19. Thermodynamics of Rubber Elasticity

    Science.gov (United States)

    Pellicer, J.; Manzanares, J. A.; Zúñiga, J.; Utrillas, P.; Fernández, J.

    2001-02-01

    A thermodynamic study of an isotropic rubber band under uniaxial stress is presented on the basis of its equation of state. The behavior of the rubber band is compared with both that of an ideal elastomer and that of an ideal gas, considering the generalized Joule's law as the ideality criterion. First, the thermal expansion of rubber at constant stress and the change in the stress with temperature at constant length are described. Thermoelastic inversion is then considered, and the experimental observations are easily rationalized. Finally, the temperature changes observed in the adiabatic stretching of a rubber band are evaluated from the decrease of entropy with length.

  20. Influence of Rubber Size on Properties of Crumb Rubber Mortars

    Directory of Open Access Journals (Sweden)

    Yong Yu

    2016-06-01

    Full Text Available Studies on the properties and applications of rubber cement-based materials are well documented. The sizes of rubbers used in these materials varied. However, information about the effects of rubber size on the properties of rubber cement-based materials, especially pore structure, mechanical strengths, and drying shrinkage properties, remains limited. Three groups of rubber with major particle sizes of 2–4 mm, 1–3 mm, and 0–2 mm were selected in this study. This paper presents experimental studies on the effects of rubber size on the consistency, fresh density, pore structure, mechanical properties, and drying shrinkage properties of crumb rubber mortars (CRMs. Results demonstrated that the consistency and fresh density of CRMs decreased with the rubber size. As to the pore structure, the total pore volume increased with the decrease of the rubber size. By contrast, the influence of the rubber size on the mesopore (<50 nm volume is not as significant as that of the rubber content. The mechanical properties of CRMs decreased with the rubber size. Low rubber stiffness and large pore volumes, especially those of small sized rubbers, contribute to the reduction of CRMs strength. The drying shrinkage of CRM increases as the rubber size decreases. The influences of rubber size on capillary tension are not significant. Thus, the shrinkage increases with the decrease of rubber size mainly because of its function in the deformation modulus reduction of CRMs.

  1. Blue rubber bleb naevus

    Directory of Open Access Journals (Sweden)

    Mittal R

    1995-01-01

    Full Text Available A 35 year old female had multiple progressive painful, tender, soft, bluish compressible nodules with the feel of rubber nipples. There was no evidence of gastrointestinal haemangiomas or other systemic abnormalities. Histopathologically, cavernous haemangioma with prominent smooth muscle outline proved the clinical diagnosis of blue rubber bleb naevus. Only cutaneous lesions were seen in the patient.

  2. 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 v

  3. Dynamic Analysis of The Intelligent Sprayer Boom

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Maagaard, Jørgen; Terp, Christian Istjord

    and not the surroundings. However this requires that the boom movements are predictable and based on data from field tests. At field tests a first version of the newly developed camera system was tested in 2010. At the field test it was found that the vertical boom movements where too big for the camera weed prediction...... system to work properly. At the University of Southern Denmark (SDU) a patent for an active damping system of the sprayer boom has been obtained. The subject of this paper is analysis of the dynamics of the Sprayer boom. The analysis is based on a Multibody Dynamics model of the sprayer boom and is made...... in Matlab. The model is made in order to analyse the boom movements. The purpose of the model is to support the development of the patented active damping system for the sprayer boom. The Multibody Dynamics model has been made based on data retrieved from a CAD model and a Finite Element model...

  4. Natural rubber biosynthesis in plants: rubber transferase.

    Science.gov (United States)

    Cornish, Katrina; Xie, Wenshuang

    2012-01-01

    Rubber biosynthesis in plants is a fascinating biochemical system, which evolved at the dawn of the dicotyledoneae and is present in at least four of the dictolydonous superorders. Rubber biosynthesis is catalyzed by a membrane complex in a monolayer membrane envelope, requires two distinct substrates and a divalent cation cofactor, and produces a high-molecular-weight isoprenoid polymer. A solid understanding of this system underpins valuable papers in the literature. However, the published literature is rife with unreliable reports in which the investigators have fallen into traps created by the current incomplete understanding of the biochemistry of rubber synthesis. In this chapter, we attempt to guide both new and more established researchers around these pitfalls.

  5. 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.

  6. 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.)

  7. Maternal health and the baby boom

    National Research Council Canada - National Science Library

    Albanesi, Stefania; Olivetti, Claudia

    2014-01-01

    .... Our hypothesis is that the improvements in maternal health contributed to the mid‐twentieth century baby boom and generated a rise in women's human capital, ultimately leading to a decline in desired fertility for subsequent cohorts...

  8. Global Synethetic Rubber Industrial Outlook

    Institute of Scientific and Technical Information of China (English)

    Dr.Leon Loh

    2011-01-01

    @@ This paper is to compile and analyze the statistical data of synthetic rubber capacity and consumption to understand its impact of supply/demand on the global synthetic rubber market.Some forecasted consumption data were generated and published by the joint efforts of both IISRP(International Institute of Synthetic Rubber Producers)and IRSG(International Rubber Study group).The report also covers the observed industrial trends as well as some emerging issues in the synthetic rubber industry.

  9. Ericameria Nauseosa (rubber rabbitbrush): a complementary rubber feedstock to augment the guayule rubber production stream

    Science.gov (United States)

    Ericameria nauseosa (rubber rabbitbrush) is a highly prolific desert shrub that produces high quality natural rubber. Over the past several years we have investigated rabbitbrush’s potential as a commercial rubber feedstock. Like guayule, rabbitbrush produces natural rubber within its bark tissues a...

  10. Indian Retail Boom : The Human Perspective

    OpenAIRE

    Maan, Mahima

    2007-01-01

    Abstract The dissertation aims to study the Indian retail boom from the perspective of its people. The people of India have reacted in a negative way by protesting against the recent developments, especially the entry of big foreign (Wal-Mart) and domestic companies. So, it becomes interesting to know the opinion of its different sections of people. The various sections views were studied with respect to the advent of foreign companies, consumer ethnocentrism, the impact of retail boom a...

  11. Activities of the Boom and Chassis Group

    Science.gov (United States)

    dell, Jason Scott; Meeks, Thomas Bayne; Merkel, Kelly; Nelson, Brent; Winchell, Tom

    Group One of the NASA Lunar Enabler Project has designed the primary chassis and boom structures for the lunar vehicle. Both components also feature V-clamps that were adapted to interface connections within the structure. The chassis features a front end, rear end section, middle cross-section, and face plate. The rear section contains an extra compartment for the engine, hydraulic pump, fuel bottles, and oil reservoir necessary for the wheel drives. Each section consists of tubular aluminum 6061-T6. The boom features four degrees of freedom system, where the minimum factor of safety of any part is 1.5 (but, normally much higher). It consists of a tapered upper boom, lower boom, and three elbows that complement the articulation joints. Each section of the boom has been constructed from aluminum 6061-T6. There are four joints and eight V-clamps in the boom assembly. The V-clamps feature support rings that prevent axial rotation. They provide easy adaptability and assembly.

  12. Runaway Rubber Removal

    Science.gov (United States)

    1989-01-01

    High hysteresis Good tract;on characteristic Poor affinity for blending Polyisoprene PI Strong wear resistance Very similar to natural rubber Low...with a "base of cresylic acid and a blend of benzene, with a synthetic detergent for a wetting agent" are recommended [8]. For AC runways, alkaline...you expect the runway to change after rubber is removed? Response Maintenance Operations Pilots Improved Skid Resistance! Brak inq Act ion/Fr ictior 7

  13. Through the Technology Lens: The Expansion of Rubber and its Implications in Montane Mainland Southeast Asia

    Directory of Open Access Journals (Sweden)

    Jefferson Fox

    2014-01-01

    Full Text Available Natural latex from the rubber tree (Hevea brasiliensis is a hot commodity, with consumption increasing worldwide at an average rate of 5.8% per year since 1900. The vast majority of the world′s rubber supply has historically come from the wet-humid tropics of Southeast Asia, but researchers in China have successfully developed new hybrids that grow well in areas with cooler temperatures and a distinct dry season. Today, investors are promoting rubber plantations in non-traditional rubber growing areas of Laos, Cambodia, Myanmar, northeast Thailand, and northwest Vietnam. By critically assessing the impacts of this expansion of rubber and clarifying the relationship between tools and technologies, the paper suggests that the widespread adoption of rubber as a technology leads to loss of natural and agricultural biodiversity; greater use of surface and groundwater supplies; increased use of pesticides, fertilisers, and other chemicals; higher exposure to market booms and busts for smallholders and investors; and for some farmers, the loss of their land to industrial plantations on which they may become labourers. The paper argues that if state authorities recognise the double-edged nature of rubber as a technology, they can act to try to limit its damaging effects through polices that recognise secure tenure and encourage small-scale, diversified agroforestry systems.

  14. Waveform Freezing of Sonic Booms Revisited

    Science.gov (United States)

    Cleveland, Robin O.; Blackstock, David T.

    1996-01-01

    Nonlinear distortion of sonic booms propagating in the atmosphere is strongly affected by stratification and geometrical spreading. For a downward propagating sonic boom in a standard atmosphere, stratification and spreading cause a slowing down of nonlinear distortion. In certain cases a stage is reached where no further distortion takes place. When this happens, the waveform is said to be frozen. In previous work the authors argued that for most HSCT designs and flight conditions being considered, the sonic boom is not frozen when it reaches the ground. The criterion used was the value of the distortion distance x bar is a measure of the nonlinear distortion suffered by the wave (and is closely related to Hayes's E variable). The aircraft must be at an altitude greater than 27 km (80,000 ft) for x bar at the groun be within 95% of its asymptotic value. However, work reported here demonstrates that the ground waveform is much closer to the frozen state than indicated by the previous analysis. In the new analysis, duration of the sonic boom is used as the criterion for judging closeness of approach tz frozen state. In order for the duration of the sonic boom at the ground to be within 95% of its frozen value, the flight altitude of the aircraft needs to be only 15 km (45,000 ft).

  15. Sonic boom focusing prediction and delta wing shape optimization for boom mitigation studies

    Science.gov (United States)

    Khasdeo, Nitin

    Supersonic travel over land would be a reality if new aircraft are designed such that they produce quieter ground sonic booms, no louder than 0.3 psf according to the FAA requirement. An attempt is made to address the challenging goal of predicting the sonic boom focusing effects and mitigate the sonic boom ground overpressure for delta wing geometry. Sonic boom focusing is fundamentally a nonlinear phenomenon and can be predicted by numerically solving the nonlinear Tricomi equation. The conservative time domain scheme is developed to carry out the sonic boom focusing or super boom studies. The computational scheme is a type differencing scheme and is solved using a time-domain scheme, which is called a conservative type difference solution. The finite volume method is used on a structured grid topology. A number of input signals Concorde wave, symmetric and ax symmetric ramp, flat top and typical N wave type are simulated for sonic boom focusing prediction. A parametric study is launched in order to investigate the effects of several key parameters that affect the magnitude of shock wave amplification and location of surface of amplification or "caustics surface." A parametric studies includes the effects of longitudinal and lateral boundaries, footprint and initial shock strength of incoming wave and type of input signal on sonic boom focusing. Another very important aspect to be looked at is the mitigation strategies of sonic boom ground signature. It has been decided that aerodynamic reshaping and geometrical optimization are the main goals for mitigating the ground signal up to the acceptance level of FAA. Biconvex delta wing geometry with a chord length of 60 ft and maximum thickness ratio of 5% of the chord is used as a base line model to carry out the fundamental research focus. The wing is flying at an altitude 40,000 ft with a Mach number of 2.0. Boom mitigation work is focused on investigating the effects of wing thickness ratio, wing camber ratio, wing

  16. Experimental and Computational Sonic Boom Assessment of Lockheed-Martin N+2 Low Boom Models

    Science.gov (United States)

    Cliff, Susan E.; Durston, Donald A.; Elmiligui, Alaa A.; Walker, Eric L.; Carter, Melissa B.

    2015-01-01

    Flight at speeds greater than the speed of sound is not permitted over land, primarily because of the noise and structural damage caused by sonic boom pressure waves of supersonic aircraft. Mitigation of sonic boom is a key focus area of the High Speed Project under NASA's Fundamental Aeronautics Program. The project is focusing on technologies to enable future civilian aircraft to fly efficiently with reduced sonic boom, engine and aircraft noise, and emissions. A major objective of the project is to improve both computational and experimental capabilities for design of low-boom, high-efficiency aircraft. NASA and industry partners are developing improved wind tunnel testing techniques and new pressure instrumentation to measure the weak sonic boom pressure signatures of modern vehicle concepts. In parallel, computational methods are being developed to provide rapid design and analysis of supersonic aircraft with improved meshing techniques that provide efficient, robust, and accurate on- and off-body pressures at several body lengths from vehicles with very low sonic boom overpressures. The maturity of these critical parallel efforts is necessary before low-boom flight can be demonstrated and commercial supersonic flight can be realized.

  17. Ready for the boom; Bereit fuer den Aufschwung

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Valerie

    2011-07-01

    The turnkey production plants of Oerlikon solar and Applied Materials started the thin film boom three years ago. After a period of slack, the boom is now continuing, not only for advanced silicon films but also for CIGS.

  18. Biodesulfurization of rubber materials

    Energy Technology Data Exchange (ETDEWEB)

    Torma, A.E. (EG and G Idaho, Inc., Idaho Falls, ID (USA)); Raghavan, D. (Illinois Univ., Urbana, IL (USA). Dept. of Materials Science and Engineering)

    1990-01-01

    One of the most challenging problems in municipal waste treatment is the recycling of polymeric waste materials. The present study has demonstrated the applicability of biotechnological principles in the desulfurization of rubber using shake flask and Warburg respirometric techniques. In terms of oxygen uptake and specific rate of oxygen uptake, it was found that the mixed culture of Thiobacillus ferrooxidans and Thiobacillus thiooxidans was more efficient in this process than the individual pure cultures of these bacteria. Furthermore, the mixed cultures resulted in ten times higher sulfur removals from rubber relative to those of sterile controls. Additional studies are needed to elucidate the mechanisms of biodesulfurization of rubber. It is expected that the development of this process may provide a solution to recycling of car tire materials. 32 refs., 4 figs., 3 tabs.

  19. Active suspension for a field sprayer boom

    DEFF Research Database (Denmark)

    Nielsen, Henrik Skovsgaard; Sørensen, Paul Haase

    1998-01-01

    The possibilities of implementing an active boom suspension is investigated. The performance improvement of an active suspension over a traditional passive one is studied in simulation, and shows a significant improvement. A closed-loop control system involving two ultrasonic distance transducers...

  20. The Baby Boom--Entering Midlife.

    Science.gov (United States)

    Bouvier, Leon F.; De Vita, Carol J.

    1991-01-01

    The U.S. baby-boom generation, born between 1946 and 1964, is the largest generation in the nations's history. Numbering over 80 million people in 1990, this giant generation has indelibly changed U.S. society, requiring adjustments in schools, labor markets, housing markets, and government programs. Perhaps more than any other institution,…

  1. GLOBAL Auto Shows Boom in 2007

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ China's independent brands have been booming in recent years when the country's auto industry has seen a rapid growth. They have attracted the global attention, but still need to upgrade constantly whether in technology or business performance in order to strengthen their presence in the global market and become internationalized.

  2. Flow distortion on boom mounted cup anemometers

    Energy Technology Data Exchange (ETDEWEB)

    Lindeloew-Marsden, P.; Pedersen, Troels F.; Gottschall, J.; Vesth, A.; Paulsen, R.W.U.; Courtney, M.S.

    2010-08-15

    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 with booms at the same height but pointing in 60 deg. different directions. In the examined case of a 1.9 m wide equilateral triangular lattice tower with booms protruding 4.1 m at 80 m height the measurement errors are observed to reach up to +- 2 %. Errors of this magnitude are severely problematic in the measurement of wind turbine power performance, wind resource assessment and for providing purposeful in-field comparisons between different sensors, e.g. lidar anemometers. With the proposed method, direction dependent errors can be extracted and the mast flow distortion effect on the wind measurements corrected to an uncertainty estimated to better than 0.5%. This level of uncertainty is probably acceptable for the above mentioned applications. (author)

  3. The post-opium scenario and rubber in northern Laos: Alternative Western and Chinese models of development.

    Science.gov (United States)

    Cohen, Paul T

    2009-09-01

    In the past few years rubber planting has spread rapidly throughout northern Laos, especially in Luang Namtha province that borders China. The impetus for this boom has come partly from the spiralling demand for rubber in China (now the world's largest rubber consumer), the high world prices for rubber, and China's promotion of overseas investment through its opium-replacement policy. These economic factors have converged with the desperate need of impoverished highlanders in northern Laos to replace opium as a cash crop as a consequence of a recent opium-eradication campaign and inadequate alternative development. This paper draws upon ethnographic and agro-economic research in northern Laos and neighbouring regions and reports of international development organisations operating in Laos. The rubber boom in northern Laos represents a fundamental clash between Western drug-oriented alternative development, on the one hand, and China's national economic strategies abroad and investment-led narcotics policy, on the other. China's opium-replacement policy has contributed to a type of unregulated frontier capitalism with socio-economic and environmental effects that threaten the principles and goals of alternative development and even to marginalise the role international development organisations in northern Laos.

  4. Effect of Rubber Particle Modification on Properties of Rubberized Concrete

    Institute of Scientific and Technical Information of China (English)

    ZHANG Haibo; GOU Mifeng; LIU Xiaoxing; GUAN Xuemao

    2014-01-01

    To improve the combination of cement matrix and waste tire rubber particles in concrete, the rubber particles were treated with acrylic acid (ACA) and polyethylene glycol (PEG) for grafting hydrophilic groups on their surfaces. The X-Ray photoelectron spectroscopy (XPS) and surface contact angle were used to characterize the hydrophilicity and surface functional group of rubber particles. The effect of rubber particle modification on fresh/hardened properties of rubberized concrete was studied. The experimental results show that the contact angle between rubber particle surface and water decreases when rubber particle is modified. Compared with the unmodified rubberized concrete(RC), the unit weight of modified rubberized concrete(MRC) changes slightly. However, the slump, air-entrainment, compressive strength, flexural strength, and impact performance of MRC are obviously improved. Under good condition of slump, the water-cement ratio of the MRC can be reduced from 0.4 to 0.38. And the compressive strength and flexural strength of the MRC(10%rubber particle content) can be increased by 25.9%and 26.4%, respectively.

  5. 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...... in the measurement of wind turbine power performance, wind resource assessment and for providing purposeful in-field comparisons between different sensors, e.g. lidar anemometers. With the proposed method, direction dependent errors can be extracted and the mast flow distortion effect on the wind measurements...

  6. Residual stresses in rubber formed thermoplastic composites

    NARCIS (Netherlands)

    Wijskamp, Sebastiaan; Lamers, E.A.D.; Akkerman, Remko; Brucato, V.

    2003-01-01

    The rubber pressing process is applied for the rapid production of thermoplastic composite products. However, rubber pressed products show geometrical distortions, such as warpage, due to processinduced residual stresses. An experimental study is performed to measure the curvature after rubber

  7. On The Thermal Consolidation Of Boom Clay

    CERN Document Server

    Delage, Pierre; Cui, Yu-Jun

    2012-01-01

    When a mass of saturated clay is heated, as in the case of host soils surrounding nuclear waste disposals at great depth, the thermal expansion of the constituents generates excess pore pressures. The mass of clay is submitted to gradients of pore pressure and temperature, to hydraulic and thermal flows, and to changes in its mechanical properties. In this work, some of these aspects were experimentally studied in the case of Boom clay, so as to help predicting the response of the soil, in relation with investigations made in the Belgian underground laboratory at Mol. Results of slow heating tests with careful volume change measurements showed that a reasonable prediction of the thermal expansion of the clay-water system was obtained by using the thermal properties of free water. In spite of the density of Boom clay, no significant effect of water adsorption was observed. The thermal consolidation of Boom clay was studied through fast heating tests. A simple analysis shows that the hydraulic and thermal trans...

  8. Preparation of Hydrogenated Nitrile Rubber

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Hydrogenated nitrile rubber is an oil and solvent resistant rubber and particularly give more resistant to heat, ozone, light. It is generally prepared from nitrile rubber by selective hydrogenation using a suitable catalyst system. In the present work a prepared method was adapted for the hydrogenation reaction of nitrile rubber using homogeneous tris(tri-phenlphosphine)chlorhodium(I) catalyst (RhCl(PPh3)) system. The hydrogenation reaction was carriedout at different temperature, pressure, time and catalyst concentration, the concentration, the conditions of hydrogenation are stated in table 1.

  9. QENS investigation of filled rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Triolo, A.; Lechner, R.E.; Desmedt, A.; Pieper, J. [CNR - Istituto per i Processi Chimico-Fisici, sez. Messina, Via La Farina 237, 98123 Messina (Italy); Lo Celso, F.; Triolo, R. [Dip. Chimica Fisica, V. le delle Scienze, Parco d' Orleans, Padiglione 17, Universita di Palermo, 90128 Palermo (Italy); Negroni, F. [Pirelli Pneumatici S.p.A, V. le Sarca 222, 20126 Milano (Italy); Arrighi, V.; Qian, H. [Chemistry School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS Edinburgh (United Kingdom); Frick, B. [Institut Laue-Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble, Cedex 9 (France)

    2002-07-01

    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.)

  10. 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.)

  11. QENS investigation of filled rubbers

    Science.gov (United States)

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

    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.

  12. Preparation of Hydrogenated Nitrile Rubber

    Institute of Scientific and Technical Information of China (English)

    LIU; ZhiCai

    2001-01-01

    Hydrogenated nitrile rubber is an oil and solvent resistant rubber and particularly give more resistant to heat, ozone, light. It is generally prepared from nitrile rubber by selective hydrogenation using a suitable catalyst system. In the present work a prepared method was adapted for the hydrogenation reaction of nitrile rubber using homogeneous tris(tri-phenlphosphine)chlorhodium(I) catalyst (RhCl(PPh3)) system.  The hydrogenation reaction was carriedout at different temperature, pressure, time and catalyst concentration, the concentration, the conditions of hydrogenation are stated in table 1.  ……

  13. Laboratory performance of asphalt rubber mixtures

    OpenAIRE

    Fontes, Liseane; Trichês, Glicério; Pais, Jorge; Pereira, Paulo; Minhoto, Manuel

    2009-01-01

    Asphalt rubber mixtures are one of the most promising techniques to extend the service life of asphalt pavement overlays. Asphalt rubber binder is composed of crumb rubber from reclaimed tires and conventional asphalt. The asphalt rubber binder can be obtained through wet process in two different systems: tire rubber modified asphalt binder (produced at industrial plants) and continuous blending (produced in asphalt plants). This study presents a laboratory evaluation of asphalt rubber mixtur...

  14. CRIA Sians A areement with Rubber Valley

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The signing ceremony of establishing strategic partnership between China Rubber Industry Association and Rubber Valley Co., Ltd. was held in Rubber Valley on September 13. Leaders such as Xu Wenying, Deputy Secretary-General of CRIA, repre-senting CRIA, and Zhang Yan, Deputy Director of Rubber Valley Management Committee and General Manager of Rubber Valley Co., Ltd., representing Rubber Valley, signed on the cooperation agreement. Fan Rende, President of CRIA, Cai Quanji,

  15. 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 r

  16. Warpage of rubber pressed composites

    NARCIS (Netherlands)

    Wijskamp, Sebastiaan; Lamers, E.A.D.; Akkerman, Remko; van de Ven, Erik

    2002-01-01

    The rubber pressing process is applied for the rapid production of thermoplastic composite products. However, rubber pressed products show geometrical distortions, such as warpage, due to process-induced residual stresses. It is believed that these stresses build up as a result of the large thermal

  17. Engineered Plastics Containing Recycled Rubber

    Institute of Scientific and Technical Information of China (English)

    Dong Yang Wu

    2000-01-01

    @@ 1. Introduction In Australia 10.5 million rubber tyres are discarded annually, representing 120,000 tonnes of wasted rubber resource. Growing local and global concern about the impact of this waste on the environment requires action for the management and recycling of this highly valuable resource through the development of recycling technologies and innovative recycled/recyclable products.

  18. Rubber compounding and processing

    CSIR Research Space (South Africa)

    John

    2014-06-01

    Full Text Available stream_source_info John_2014_ABSTRACT ONLY.pdf.txt stream_content_type text/plain stream_size 886 Content-Encoding ISO-8859-1 stream_name John_2014_ABSTRACT ONLY.pdf.txt Content-Type text/plain; charset=ISO-8859...-1 Handbook of Green Materials Processing Technologies, Properties and Applications Chapter 15 RUBBER COMPOUNDING AND PROCESSING MAYA JACOB JOHN1,2 1CSIR Materials Science and Manufacturing, Polymers and Composites Competence Area, P.O. Box 1124...

  19. Multidisciplinary design optimization for sonic boom mitigation

    Science.gov (United States)

    Ozcer, Isik A.

    Automated, parallelized, time-efficient surface definition and grid generation and flow simulation methods are developed for sharp and accurate sonic boom signal computation in three dimensions in the near and mid-field of an aircraft using Euler/Full-Potential unstructured/structured computational fluid dynamics. The full-potential mid-field sonic boom prediction code is an accurate and efficient solver featuring automated grid generation, grid adaptation and shock fitting, and parallel processing. This program quickly marches the solution using a single nonlinear equation for large distances that cannot be covered with Euler solvers due to large memory and long computational time requirements. The solver takes into account variations in temperature and pressure with altitude. The far-field signal prediction is handled using the classical linear Thomas Waveform Parameter Method where the switching altitude from the nonlinear to linear prediction is determined by convergence of the ground signal pressure impulse value. This altitude is determined as r/L ≈ 10 from the source for a simple lifting wing, and r/L ≈ 40 for a real complex aircraft. Unstructured grid adaptation and shock fitting methodology developed for the near-field analysis employs an Hessian based anisotropic grid adaptation based on error equidistribution. A special field scalar is formulated to be used in the computation of the Hessian based error metric which enhances significantly the adaptation scheme for shocks. The entire cross-flow of a complex aircraft is resolved with high fidelity using only 500,000 grid nodes after only about 10 solution/adaptation cycles. Shock fitting is accomplished using Roe's Flux-Difference Splitting scheme which is an approximate Riemann type solver and by proper alignment of the cell faces with respect to shock surfaces. Simple to complex real aircraft geometries are handled with no user-interference required making the simulation methods suitable tools for

  20. Down-regulation of small rubber particle protein expression affects integrity of rubber particles and rubber content in Taraxacum brevicorniculatum.

    Directory of Open Access Journals (Sweden)

    Andrea Hillebrand

    Full Text Available The biosynthesis of rubber is thought to take place on the surface of rubber particles in laticifers, highly specialized cells that are present in more than 40 plant families. The small rubber particle protein (SRPP has been supposed to be involved in rubber biosynthesis, and recently five SRPPs (TbSRPP1-5 were identified in the rubber-producing dandelion species Taraxacum brevicorniculatum. Here, we demonstrate by immunogold labeling that TbSRPPs are localized to rubber particles, and that rubber particles mainly consist of TbSRPP3, 4 and 5 as shown by high-resolution two-dimensional gel electrophoresis and mass spectrometric analysis. We also carried out an RNA-interference approach in transgenic plants to address the function of TbSRPPs in rubber biosynthesis as well as rubber particle morphology and stability. TbSRPP-RNAi transgenic T. brevicorniculatum plants showed a 40-50% reduction in the dry rubber content, but neither the rubber weight average molecular mass nor the polydispersity of the rubber were affected. Although no phenotypical differences to wild-type particles could be observed in vivo, rubber particles from the TbSRPP-RNAi transgenic lines were less stable and tend to rapidly aggregate in expelling latex after wounding of laticifers. Our results prove that TbSRPPs are very crucial for rubber production in T. brevicorniculatum, probably by contributing to a most favourable and stable rubber particle architecture for efficient rubber biosynthesis and eventually storage.

  1. Down-regulation of small rubber particle protein expression affects integrity of rubber particles and rubber content in Taraxacum brevicorniculatum.

    Science.gov (United States)

    Hillebrand, Andrea; Post, Janina J; Wurbs, David; Wahler, Daniela; Lenders, Malte; Krzyzanek, Vladislav; Prüfer, Dirk; Gronover, Christian Schulze

    2012-01-01

    The biosynthesis of rubber is thought to take place on the surface of rubber particles in laticifers, highly specialized cells that are present in more than 40 plant families. The small rubber particle protein (SRPP) has been supposed to be involved in rubber biosynthesis, and recently five SRPPs (TbSRPP1-5) were identified in the rubber-producing dandelion species Taraxacum brevicorniculatum. Here, we demonstrate by immunogold labeling that TbSRPPs are localized to rubber particles, and that rubber particles mainly consist of TbSRPP3, 4 and 5 as shown by high-resolution two-dimensional gel electrophoresis and mass spectrometric analysis. We also carried out an RNA-interference approach in transgenic plants to address the function of TbSRPPs in rubber biosynthesis as well as rubber particle morphology and stability. TbSRPP-RNAi transgenic T. brevicorniculatum plants showed a 40-50% reduction in the dry rubber content, but neither the rubber weight average molecular mass nor the polydispersity of the rubber were affected. Although no phenotypical differences to wild-type particles could be observed in vivo, rubber particles from the TbSRPP-RNAi transgenic lines were less stable and tend to rapidly aggregate in expelling latex after wounding of laticifers. Our results prove that TbSRPPs are very crucial for rubber production in T. brevicorniculatum, probably by contributing to a most favourable and stable rubber particle architecture for efficient rubber biosynthesis and eventually storage.

  2. 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.

  3. 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.; Rosenberger, James L.; Philips, Daisy

    2014-01-01

    The Waveforms and Sonic boom Perception and Response (WSPR) Program was designed to test and demonstrate the applicability and effectiveness of techniques to gather data relating human subjective response to multiple low-amplitude sonic booms. It was in essence a practice session for future wider scale testing on naive communities, using a purpose built low-boom demonstrator aircraft. The low-boom community response pilot experiment was conducted in California in November 2011. The WSPR team acquired sufficient data to assess and evaluate the effectiveness of the various physical and psychological data gathering techniques and analysis methods.

  4. Perspectiva profesional frente a la violencia

    Directory of Open Access Journals (Sweden)

    Vera Bernal Yolanda

    1996-06-01

    Full Text Available

    En este ensayo se analiza el compromiso actual de las ciencias de la salud, específicamente de la Facultad de Enfermería frente a la violencia y algunas consideraciones sobre la manera de enfrentarla. Diariamente los medios de comunicación tocan el tema de la violencia en nuestro país: secuestros, muertes, atentados, terrorismo etc., pero son pocas las ocasiones en que es tratado objetivamente, puesto que lo que prima es la "guerra del rating" y no el llamado a la reflexión y a la propuesta de soluciones frente a este flagelo que cada día azota más seres humanos.

     

  5. 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.

  6. El Partido Comunista y el frente popular

    Directory of Open Access Journals (Sweden)

    Pierre BROUÉ

    2010-02-01

    Full Text Available Tengo que confesar que para mí, siendo profesor en Francia y además en la provincia, no es fácil tratar de hacer un estado de cuestión sobre la guerra civil. Hagan el favor de disculparme si no fui capaz de estudiar todos los libros y revistas históricas. Durante cinco años, el único trabajo que recibí sobre la guerra civil fue el de Aróstegui y Martínez sobre la Junta de Defensa de Madrid1, y las bibliotecas francesas no son ricas en el tema. Sin embargo voy a exponer mi opinión sobre las relaciones entre el Partido Comunista de España y las otras organizaciones obreras de la izquierda, incluyendo en mi estudio no sólo las del Frente popular propiamente dicho, sino también las organizaciones y grupos a su margen, es decir no sólo los anarquistas, FAI y CNT, miembros en 1938 del Frente popular, sino también el POUM que fue uno de los firmantes del programa electoral de las izquierdas del 15 de Enero de 1936, primera forma española del Frente popular.

  7. Nano-reinforcement of tire rubbers: silica-technology for natural rubber : exploring the infuence of non-rubber constituents on the natural rubber-silica system

    NARCIS (Netherlands)

    Sarkawi, S.S.

    2013-01-01

    Natural rubber is a renewable resource material with outstanding properties which offers significant advantages over its counterparts, the fossil-resource synthetic rubbers. In fact, a natural rubber tree is an efficient carbon dioxide sequester. Since natural rubber is a natural product, it is subj

  8. Hydrogenated nitrile rubber for improved durability of automotive rubber parts

    Energy Technology Data Exchange (ETDEWEB)

    Mirza, J.; Leibbrandt, F.; Thoermer, J.

    1987-01-01

    Rubber articles with improved heat resistance and better performance characteristics are becoming of increasing importance for the automotive industry. A new type of elastomer has therefore been developed based on saturated hydrocarbon backbone - for improved heat resistance - with nitrile side groups providing good resistance to swelling. Some of the typical characteristics of hydrogenated nitrile rubber (HNBR) vulcanizates such as good physical properties pattern at elevated low temperatures dynamic properties, ozone resistance and swelling in automotive fluids are discussed. Potential applications are suggested to improve the performance of various rubber parts used in automotive applications such as high performance seals.

  9. Looking for Japan's missing third baby boom.

    Science.gov (United States)

    Baba, Sachiko; Goto, Aya; Reich, Michael R

    2017-10-10

    High-income countries are now experiencing a decline in fertility. After experiencing baby booms in 1947-1949 and 1971-1974, Japan's population has been decreasing since 2015. In an attempt to predict the next baby boom, we searched for any upward demographic trends occurring after 1974. We analyzed time trends of the numbers and rates of live births, stillbirths and induced abortions using Japanese government data from 1975 to 2014. We then selected two birth cohorts: the first baby boomers who were 0-4 years old in 1950, and the second baby boomers who were 0-4 years old in 1975, and analyzed their rates of live births, stillbirths, and abortions by five-year age groups. There was no upswing in the numbers of births, stillbirths, or induced abortions; however, the abortion rate increased during 1996-2002. Compared with the first baby boomer cohort, the second baby boomer cohort had half the peak live birth rate for the same age group (25-29 years old), and half the peak rate of abortions, with a shift toward a younger age group (20-24). This analysis of Japanese fertility trends derived from all pregnancy outcomes showed no upward trend in fertility in Japan since 1974. © 2017 Japan Society of Obstetrics and Gynecology.

  10. Doppler effect induced spin relaxation boom

    Science.gov (United States)

    Zhao, Xinyu; Huang, Peihao; Hu, Xuedong

    2016-03-01

    We study an electron spin qubit confined in a moving quantum dot (QD), with our attention on both spin relaxation, and the product of spin relaxation, the emitted phonons. We find that Doppler effect leads to several interesting phenomena. In particular, spin relaxation rate peaks when the QD motion is in the transonic regime, which we term a spin relaxation boom in analogy to the classical sonic boom. This peak indicates that a moving spin qubit may have even lower relaxation rate than a static qubit, pointing at the possibility of coherence-preserving transport for a spin qubit. We also find that the emitted phonons become strongly directional and narrow in their frequency range as the qubit reaches the supersonic regime, similar to Cherenkov radiation. In other words, fast moving excited spin qubits can act as a source of non-classical phonons. Compared to classical Cherenkov radiation, we show that quantum dot confinement produces a small but important correction on the Cherenkov angle. Taking together, these results have important implications to both spin-based quantum information processing and coherent phonon dynamics in semiconductor nanostructures.

  11. 33 CFR 401.32 - Cargo booms-deck cargo.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Cargo booms-deck cargo. 401.32... OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Seaway Navigation § 401.32 Cargo booms—deck cargo. (a) Every vessel shall have cargo booms secured in a manner that affords maximum...

  12. Baby Boom Equals Career Bust. Monographs on Career Education.

    Science.gov (United States)

    Moore, Charles Guy

    Presenting the Baby Boom (1946-1965) as both a potential social problem and opportunity for American leadership, this monograph discusses the following aspects of this population concern: (1) its immediate and long-term impact on career opportunities for those college graduates who make up the baby boom generation; (2) its impact on those whose…

  13. Physicians workforce: legal immigrants will extend baby boom demands.

    Science.gov (United States)

    2005-10-15

    The baby boom generation will place large demands on the Medicare program and the U.S. health care system. These demands may be extended by a large legal immigrant population that will become Medicare-eligible soon after the baby boom generation does. The U.S. health care system should be prepared for sustained stress from this again population.

  14. Rubber friction on (apparently) smooth lubricated surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mofidi, M; Prakash, B [Division of Machine Elements, Luleaa University of Technology, Luleaa SE-97187 (Sweden); Persson, B N J [IFF, FZ-Juelich, 52425 Juelich (Germany); Albohr, O [Pirelli Deutschland AG, 64733 Hoechst/Odenwald, Postfach 1120 (Germany)

    2008-02-27

    We study rubber sliding friction on hard lubricated surfaces. We show that even if the hard surface appears smooth to the naked eye, it may exhibit short-wavelength roughness, which may make the dominant contribution to rubber friction. That is, the observed sliding friction is mainly due to the viscoelastic deformations of the rubber by the counterface surface asperities. The results presented are of great importance for rubber sealing and other rubber applications involving (apparently) smooth surfaces.

  15. Rubber friction on (apparently) smooth lubricated surfaces

    Science.gov (United States)

    Mofidi, M.; Prakash, B.; Persson, B. N. J.; Albohr, O.

    2008-02-01

    We study rubber sliding friction on hard lubricated surfaces. We show that even if the hard surface appears smooth to the naked eye, it may exhibit short-wavelength roughness, which may make the dominant contribution to rubber friction. That is, the observed sliding friction is mainly due to the viscoelastic deformations of the rubber by the counterface surface asperities. The results presented are of great importance for rubber sealing and other rubber applications involving (apparently) smooth surfaces.

  16. Boom clay borehole water, home of a diverse bacterial community

    Energy Technology Data Exchange (ETDEWEB)

    Wouters, Katinka; Moors, Hugo; Leys, Natalie [Belgian Nuclear Research Centre (SCK-CEN), Mol (Belgium)

    2013-07-01

    For over two decades, Boom Clay has been studied in the framework of geological disposal of nuclear waste thereby mainly addressing its geochemical properties. Today, also the microbiological properties and the possibility of microbes interacting with radionuclides or repository components including the waste form, in a host formation like Boom Clay are considered [2,3]. In the past, a reference composition for synthetic Boom Clay pore water (BCPW) was derived, based on interstitial water sampled from different layers within the Boom clay [1]. Similarly, the primary aim of this microbiological study was to determine the core BCPW bacterial community and identify representative water samples for future microbial directed lab experiments. In this respect, BCPW was sampled from different Boom Clay layers using the Morpheus piezometer and subsequently analysed by microscopy and molecular techniques, in search for overall shared and abundant micro-organisms. (authors)

  17. Juventud y medios de comunicación frente a frente

    OpenAIRE

    C. Naval; Sádaba, Ch. (Charo)

    2005-01-01

    Más que dos realidades frente a frente, juventud y medios de comunicación no sólo se armonizan bien sino que se reclaman mutuamente. Junto a ellos, la sociedad, padres y educadores se preguntan en qué medida esta relación, a veces tan intensa, puede favorecer o perjudicar a la formación de los jóvenes, en pleno desarrollo de la personalidad. Los medios, muchas veces excesivos en sus formas y contenidos, presentan una realidad no siempre ajustada en sus términos. El objetivo de este artícul...

  18. Baby boom generation at the retirement onset

    Directory of Open Access Journals (Sweden)

    Stojilković Jelena

    2010-01-01

    Full Text Available Sudden increase in the number of live births after the Second World War due to an increase in fertility rates has led to the formation of cohorts with specific characteristics or baby boom generation. This generation is unique in the history of the demographic phenomenon that has affected and affects the functioning of many segments of society. The aim of this paper is to assess structure of baby boomers who are few years away from retirement, using demographic data. Impact of baby boomer age structure of current and future retirees is described with a graphical display of current and projected age pyramid of baby boomers. Demographic pattern that women live longer than men is evident in the projected pyramid. In addition, the number of baby boomers will lead to a "younger" old population. The imbalance in the number of men and women pensioners, as well as older cohorts of women and female baby boomers was analyzed. As a result, an increasing trend of women's age pensioners who are members of the baby boom generation was clearly observed, which is opposite to the older cohort of women who often were family pensioners. Different circumstances and conditions in which female boomers lived and worked will form a new "pension model" because they will gain their benefits as well as men, for the first time in significant number, unlike their mothers, which gained the right to retire after they become widows. Number of women age pensioners is getting greater comparing to men, as the result of changes in the economic activities of women in the last half of the 20th century. When baby boomers retire and exit the working population, this will create a vacuum, because the numerically smaller generations will enter working population, while the sudden and very shortly, the number of population older than 60 or 65 will increase, most of them will likely to acquire the right to a pension. It is undeniable that baby boomers had impact on demographic structure

  19. 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.

  20. Rubberized Concrete Durability Against Abrasion

    Directory of Open Access Journals (Sweden)

    Md Noor Nurazuwa

    2016-01-01

    Full Text Available Durability performance of rubberized concrete against abrasion is presented in this paper. Surface depth loss was measured when abrasion load was constantly applied on concrete surface at each 500 interval rotation. Specimen with water-to cement ratio of 0.50 and 0.35 was prepared and tested at 28 days of curing age. In addition, 10% silica fume, SF was added to provide denser concrete and to understand its effectiveness against wear when added with crumb rubber. Results showed that crumb rubber shows good potential in providing abrasion resistance to concrete mix. However, in the case of rubberized concrete with silica fume, abrasion resistance was found to be slightly decreased with compressive strength more than 50N/mm2 due to the lack of low elastic modulus of CR particles to accommodate with denser cement matrix.

  1. Manglares: ecosistema centinela frente al cambio climatico, Golfo de Mexico

    National Research Council Canada - National Science Library

    Yanez-Arancibia, Alejandro; Day, John W; Twilley, Robert R; Day, Richard H

    2014-01-01

    ...): "los manglares como habitat forestado critico de la zona costera presentan respuestas de acomodacion frente a la variabilidad ambiental que induce el cambio global, desarrollando un papel estructural...

  2. Silicone-Rubber Stitching Seal

    Science.gov (United States)

    Wang, D. S.

    1985-01-01

    Fabric products protected from raveling by coating threads and filling stitching holes with silicone rubber. Uncored silicone rubber applied to stitching lines with air-pressurized sealant gun. Next, plastic release film placed on coated side, and blanket flipped over so release film lies underneath. Blanket then bagged and adhesive cured under partial vacuum of about 3.5 psi or under pressure. Applications include balloons, parachutes, ultralight aircraft, sails, rescue harnesses, tents, or other fabric products highly stressed in use.

  3. Superheated rubber for cold storage

    Energy Technology Data Exchange (ETDEWEB)

    Katzenberg, Frank; Heuwers, Benjamin; Tiller, Joerg Christian [Biomaterials and Polymer Science, Department of Biochemical and Chemical Engineering, TU Dortmund, D-44221 Dortmund (Germany)

    2011-04-26

    Highly stretched rubber cools down upon relaxation. A natural rubber material that stores high elongations up to 1000% strain upon strain-induced crystallization at room temperature is reported. The strain recovered and, with this, the stored ''cold'' is released only by a thermal or athermal trigger. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Power outages, power externalities, and baby booms.

    Science.gov (United States)

    Burlando, Alfredo

    2014-08-01

    Determining whether power outages have significant fertility effects is an important policy question in developing countries, where blackouts are common and modern forms of family planning are scarce. Using birth records from Zanzibar, this study shows that a month-long blackout in 2008 caused a significant increase in the number of births 8 to 10 months later. The increase was similar across villages that had electricity, regardless of the level of electrification; villages with no electricity connections saw no changes in birth numbers. The large fertility increase in communities with very low levels of electricity suggests that the outage affected the fertility of households not connected to the grid through some spillover effect. Whether the baby boom is likely to translate to a permanent increase in the population remains unclear, but this article highlights an important hidden consequence of power instability in developing countries. It also suggests that electricity imposes significant externality effects on rural populations that have little exposure to it.

  5. Brazil's sugarcane boom could affect regional temperatures

    Science.gov (United States)

    Schultz, Colin

    2013-04-01

    With the world seeking to cut its dependence on fossil fuels, the use of bioethanol and other biofuels is on the rise. In Brazil, the second largest producer and consumer of bioethanol, this has led to a boom in sugarcane production. Based on new laws and trade agreements, researchers expect Brazil's production of sugarcane-derived ethanol to increase tenfold over the next decade, with considerable land being converted for growing sugarcane. Much of this expansion is expected to come at a loss of some of the country's cerrado savannas. So while a major aim of the turn to biofuels is to reduce the transfer of carbon to the atmosphere and mitigate global climate change, the shifting agricultural activity could have direct consequences on Brazil's climate by changing the region's physical and biogeochemical properties.

  6. Experimental and Computational Sonic Boom Assessment of Boeing N+2 Low Boom Models

    Science.gov (United States)

    Durston, Donald A.; Elmiligui, Alaa; Cliff, Susan E.; Winski, Courtney S.; Carter, Melissa B.; Walker, Eric L.

    2015-01-01

    Near-field pressure signatures were measured and computational predictions made for several sonic boom models representing Boeing's Quiet Experimental Validation Concept (QEVC) supersonic transport, as well as three axisymmetric calibration models. Boeing developed the QEVC under a NASA Research Announcement (NRA) contract for Experimental Systems Validations for N+2 Supersonic Commercial Transport Aircraft, which was led by the NASA High Speed Project under the Fundamental Aeronautics Program. The concept was designed to address environmental and performance goals given in the NRA, specifically for low sonic boom loudness levels and high cruise efficiency, for an aircraft anticipated to enter service in the 2020 timeframe. Wind tunnel tests were conducted on the aircraft and calibration models during Phases I and II of the NRA contract from 2011 to 2013 in the NASA Ames 9- by 7-Foot and NASA Glenn 8- by 6-Foot Supersonic Wind Tunnels. Sonic boom pressure signatures were acquired primarily at Mach 1.6 and 1.8, and force and moment data were acquired from Mach 0.8 to 1.8. The sonic boom test data were obtained using a 2-in. flat-top pressure rail and a 14-in. round-top tapered "reflection factor 1" (RF1) pressure rail. Both rails capture an entire pressure signature in one data point, and successive signatures at varying positions along or above the rail were used to improve data quality through spatial averaging. The sonic boom data obtained by the rails were validated with high-fidelity numerical simulations of off-body pressures using the CFD codes USM3D, Cart3D, and OVERFLOW. The test results from the RF1 rail showed good agreement between the computational and experimental data when a variety of testing techniques including spatial averaging of a series of pressure signatures were employed, however, reflections off the 2-in. flat-top rail caused distortions in the signatures that did not agree with the CFD predictions. The 9 x 7 and 8 x 6 wind tunnels generally

  7. 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

  8. 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...... procedure; and means for detecting the edges and estimating the angles of the edges of the leaves so as to discriminate between dicots and monocots; and means for activating one or more of the spray nozzles in response to detected dicots so as to selectively apply the herbicidal composition onto the sensed...... area containing the dicots....

  9. THERMAL CONDUCTIVITY OF RUBBERIZED GYPSUM BOARD

    Directory of Open Access Journals (Sweden)

    Taher Abu-Lebdeh

    2014-01-01

    Full Text Available The disposal of scrap tires is a challenging task and hence an innovative solution to meet these challenges is needed. Extensive work has been done on the utilization of waste tires in a variety of applications in asphalt pavements and concrete. However, previous investigations focus only on the mechanical properties of the rubberized materials, but few on the thermal performance. This is especially true for rubberized gypsum. Limited or no experimental data on the thermal performance of rubberized gypsum board are available. In this study, an experimental program is established to investigate the effect of amount and size of crumb rubber on the thermal properties of gypsum materials. Gypsum is replaced by four different percentage of crumb rubber: 10, 20, 30 and 40% by weight of gypsum and two sizes of crumb rubber (#30, #10_20 to make eight rubberized gypsum specimens. The prepared specimens were tested for thermal conductivity using an apparatus specially designed and constructed for this purpose. The experimental program was concluded by proposing an empirical equation to predict the thermal conductivity of rubberized gypsum board. Results indicated better thermal performance of the gypsum board due to the addition of crumb rubber. Thermal conductivity of the rubberized gypsum was 18-38% lower than the ordinary gypsum. It is concluded that thermal conductivity of rubberized gypsum decreases with the increase of crumb rubber regardless the size of the rubber and that thermal conductivity of mixtures contained 40% of rubber was about 38% lower than conventional mixture when crumb rubber #10_20 was added, while the thermal conductivity reduced by 22% when crumb rubber #30 was added. The study suggested for future work to investigate the effect of air voids size and ratio on the thermal conductivity of rubberized gypsum.

  10. Natural rubber latex allergy

    Directory of Open Access Journals (Sweden)

    Deval Ravi

    2008-01-01

    Full Text Available Natural rubber latex (NRL is a ubiquitous allergen as it is a component of > 40,000 products in everyday life. Latex allergy might be attributed to skin contact or inhalation of latex particles. Latex allergy is an IgE-mediated hypersensitivity to NRL, presenting a wide range of clinical symptoms such as angioedema, swelling, cough, asthma, and anaphylactic reactions. Until 1979, latex allergy appeared only as type IV delayed hypersensitivity; subsequently, the proportion of different allergy types drifted towards type IV contact allergy reactions. Several risk factors for sensitization to NRL are already known and well documented. Some authors have established a positive correlation between a history of multiple surgical interventions, atopy, spina bifida malformation, and latex allergy incidence. We suspect an increase in latex allergy incidence in association with increased atopy and sensitivity to environmental allergens in the industrial population. It is often postulated in literature that the groups of workers at risk for this allergy are essentially workers in the latex industry and healthcare professionals. In this population, direct internal and mucosal contact with NRL medical devices may be the route of sensitization as factors such as the number of procedures and use of NRL materials (catheters and tubes were associated with increased risk of latex sensitization and allergy.

  11. Elastic Deployable Composite Tubular Roll-Out Boom Project

    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...

  12. Elastic Deployable Composite Tubular Roll-Out Boom Project

    Data.gov (United States)

    National Aeronautics and Space Administration — DSS's innovative Elastic Deployable Composite Tubular Roll-Out Boom will provide revolutionary performance when compared to conventional state-of-the-art...

  13. Confidence Intervals for Laboratory Sonic Boom Annoyance Tests

    Science.gov (United States)

    Rathsam, Jonathan; Christian, Andrew

    2016-01-01

    Commercial supersonic flight is currently forbidden over land because sonic booms have historically caused unacceptable annoyance levels in overflown communities. NASA is providing data and expertise to noise regulators as they consider relaxing the ban for future quiet supersonic aircraft. One deliverable NASA will provide is a predictive model for indoor annoyance to aid in setting an acceptable quiet sonic boom threshold. A laboratory study was conducted to determine how indoor vibrations caused by sonic booms affect annoyance judgments. The test method required finding the point of subjective equality (PSE) between sonic boom signals that cause vibrations and signals not causing vibrations played at various amplitudes. This presentation focuses on a few statistical techniques for estimating the interval around the PSE. The techniques examined are the Delta Method, Parametric and Nonparametric Bootstrapping, and Bayesian Posterior Estimation.

  14. Isoprene Rubber Has Broad Market Potential

    Institute of Scientific and Technical Information of China (English)

    Xu Qingsbeng

    2007-01-01

    @@ Isoprene Rubber (IR) is a macro molecular substance polymerized from isoprene monomer, with a structure and properties that are basically similar to those of natural rubber (NR). It features excellent elasticity, wear resistance,heat resistance, low temperature flexibility, etc.

  15. 75 FR 57980 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-09-23

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Polychloroprene Rubber From Japan AGENCY: United States International Trade Commission. ACTION... whether revocation of the antidumping duty finding on polychloroprene rubber from Japan would be likely to...

  16. 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.

  17. Then and now: Reflections on two Australian mining booms

    OpenAIRE

    2011-01-01

    Australia is experiencing its largest mining boom for more than a century and a half. This paper explores, from a national perspective, important economic differences that arise when a mining boom, such as the current one, is generated by export price increases (trading gains) rather than export volume increases. Terms of trade changes - through their direct trading gain effect and indirect real GDP effect, primarily through increased employment levels - have increased Australian living stand...

  18. Case management for the baby boom generation: a strengths perspective.

    Science.gov (United States)

    Tice, C; Perkins, K

    1998-01-01

    To understand the challenges and opportunities for case management as the turn of the century approaches, we must consider the 76 million individuals born between 1946 and 1964, commonly referred to as the baby boom generation. This article examines the baby boom generation in the context of planning effective case management services. The generation's strengths are highlighted to suggest how case management systems can meet the anticipated service needs of baby boomers as they age.

  19. Tracking the Boom in Queensland’s Gasfields

    Directory of Open Access Journals (Sweden)

    Will Rifkin

    2014-09-01

    The research reported in this paper, though only mid-way to completion, suggests that an action-research approach to developing indicators of cumulative impacts on housing, business, employment, liveability and trust in government shows promise for enabling stakeholders to track the multi-faceted effects of a resource boom.  We hope that such work helps stakeholders to mitigate the ups and downs of the cycle of boom, bust and recovery that can be driven by resource development.

  20. USM3D Simulations for Second Sonic Boom Workshop

    Science.gov (United States)

    Elmiligui, Alaa; Carter, Melissa B.; Nayani, Sudheer N.; Cliff, Susan; Pearl, Jason M.

    2017-01-01

    The NASA Tetrahedral Unstructured Software System with the USM3D flow solver was used to compute test cases for the Second AIAA Sonic Boom Prediction Workshop. The intent of this report is to document the USM3D results for SBPW2 test cases. The test cases included an axisymmetric equivalent area body, a JAXA wing body, a NASA low boom supersonic configuration modeled with flow through nacelles and engine boundary conditions. All simulations were conducted for a free stream Mach number of 1.6, zero degrees angle of attack, and a Reynolds number of 5.7 million per meter. Simulations were conducted on tetrahedral grids provided by the workshop committee, as well as a family of grids generated by an in-house approach for sonic boom analyses known as BoomGrid using current best practices. The near-field pressure signatures were extracted and propagated to the ground with the atmospheric propagation code, sBOOM. The USM3D near-field pressure signatures, corresponding sBOOM ground signatures, and loudness levels on the ground are compared with mean values from other workshop participants.

  1. A revista mexicana Frente a Frente: ambiguidades e tensões entre fotomontagens vanguardistas e gravuras

    OpenAIRE

    Barbosa, Carlos Alberto Sampaio [UNESP

    2015-01-01

    O objetivo desse artigo é refletir sobre a experiência visual da revista mexicana Frente a Frente (1934-1937) publicação da Liga de Escritores y Artistas Revolucionários – LEAR (1933-1938). Após apresentar a trajetória da revista procuramos investigar o projeto visual da publicação e a complexidade de uma revista engajada e a tensão entre propostas de cultura proletária, realismo socialista e vanguarda. Procuramos averiguar a circulação da vanguarda fotográfica entre Europa e México no períod...

  2. 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...

  3. 75 FR 38119 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-07-01

    ... COMMISSION Polychloroprene 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... antidumping duty finding on polychloroprene rubber from Japan would be likely to lead to continuation or...

  4. Morphology, Tensile Strength and Oil Resistance of Gum Rubber Sheets Prepared from Lignin Modified Natural Rubber

    Directory of Open Access Journals (Sweden)

    Asrul M.

    2014-07-01

    Full Text Available The paper describes the preparation of lignin filled natural rubber latex composite and its subsequent use to obtain lignin modified rubber. Two types of lignin i.e.: rubber wood and commercial alkali lignin were used as rubber filler. Gum rubber sheets were prepared from the lignin modified rubber and their properties were compared to Standard Malaysian Rubber (SMR 20 and a type of rubber obtained from the coagulation of high ammonia latex. Rubber morphology was investigated using Scanning Electron Microscope on the cross-sectional area of cryo-fractured samples. Oil resistance of the rubber sheets was determined by measuring the mass change before and after ASTM IRM 903 oil immersion, while the tensile strengths were determined according to ASTM D412 standard. Low values of tensile strength obtained for the commercial alkali lignin modified rubber sheet relative to the rest of the rubber samples was attributed to poor lignin dispersion. This occurrence was substantiated by the SEM analysis of cryo-fractured samples where crazes and inhomogeneity was observed. Nonetheless, both lignin modified rubbers exhibited higher level of oil resistance compared to SMR 20. This is due to the nature of lignin as a hydrophilic component and its presence in the rubber matrix complicates the oil diffusion process into rubber.

  5. Container Boom in the Port of Koper

    Directory of Open Access Journals (Sweden)

    Elen Twrdy

    2012-03-01

    Full Text Available For the Port of Koper the Central and Eastern European market is very important. The Port of Koper is especially interesting for goods flows relating to the exchange of goods on the East – West route (and vice versa and bound for the EU, in particular to the catchment area of the North Adriatic ports.The year 2009 was a difficult year for business, especially due to the uncertain international economic situation. In the first nine months of 2010, 16% more goods were handled in the Port of Koper than in the same period in 2009. The container transport especially exploded in tons (45% increase as well as in container units (40% increase. Within this period they handled 355,000 TEUs (new record in the container terminal (214,000 TEUs in the same period on the seventh pier in Trieste.The growth of container transport in the Port of Koper as well as the beginning of construction on the new container terminal have made the reconstruction and extension of the current container terminal an absolute priority. The extension is in line with the estimated growth of traffic as well as with the exploitation of present and future terminal capacities.This paper aims to present and analyse: (I supply chains of the flow of containerised goods through the Port of Koper to/from the countries of Central and Eastern Europe; (II the changes which enable this boom, current state and strategies to handle even more containers in the future; (iii market potential, current and future investments in new capacities.

  6. Blue rubber bleb naevus syndrome

    DEFF Research Database (Denmark)

    Lybecker, Martin Bell; Stawowy, Marek; Clausen, Niels

    2016-01-01

    Blue rubber bleb naevus syndrome (BRBNS) is a rare vascular disorder with malformed veins, or blebs, appearing in the skin or internal organs. Gastrointestinal tract involvement is the most common feature and often subject to bleeding, potentially resulting in chronic occult blood loss and iron...

  7. 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

  8. Initial Results from the Variable Intensity Sonic Boom Propagation Database

    Science.gov (United States)

    Haering, Edward A., Jr.; Cliatt, Larry J., II; Bunce, Thomas J.; Gabrielson, Thomas B.; Sparrow, Victor W.; Locey, Lance L.

    2008-01-01

    An extensive sonic boom propagation database with low- to normal-intensity booms (overpressures of 0.08 lbf/sq ft to 2.20 lbf/sq ft) was collected for propagation code validation, and initial results and flight research techniques are presented. Several arrays of microphones were used, including a 10 m tall tower to measure shock wave directionality and the effect of height above ground on acoustic level. A sailplane was employed to measure sonic booms above and within the atmospheric turbulent boundary layer, and the sailplane was positioned to intercept the shock waves between the supersonic airplane and the ground sensors. Sailplane and ground-level sonic boom recordings were used to generate atmospheric turbulence filter functions showing excellent agreement with ground measurements. The sonic boom prediction software PCBoom4 was employed as a preflight planning tool using preflight weather data. The measured data of shock wave directionality, arrival time, and overpressure gave excellent agreement with the PCBoom4-calculated results using the measured aircraft and atmospheric data as inputs. C-weighted acoustic levels generally decreased with increasing height above the ground. A-weighted and perceived levels usually were at a minimum for a height where the elevated microphone pressure rise time history was the straightest, which is a result of incident and ground-reflected shock waves interacting.

  9. Research of low boom and low drag supersonic aircraft design

    Institute of Scientific and Technical Information of China (English)

    Feng Xiaoqiang; Li Zhanke; Song Bifeng

    2014-01-01

    Sonic boom reduction will be an issue of utmost importance in future supersonic trans-port, due to strong regulations on acoustic nuisance. The paper describes a new multi-objective optimization method for supersonic aircraft design. The method is developed by coupling Seebass-George-Darden (SGD) inverse design method and multi-objective genetic algorithm. Based on the method, different codes are developed. Using a computational architecture, a concep-tual supersonic aircraft design environment (CSADE) is constructed. The architecture of CSADE includes inner optimization level and out optimization level. The low boom configuration is gener-ated in inner optimization level by matching the target equivalent area distribution and actual equivalent area distribution. And low boom/low drag configuration is generated in outer optimiza-tion level by using NSGA-II multi-objective genetic algorithm to optimize the control parameters of SGD method and aircraft shape. Two objective functions, low sonic boom and low wave drag, are considered in CSADE. Physically reasonable Pareto solutions are obtained from the present optimization. Some supersonic aircraft configurations are selected from Pareto front and the optimization results indicate that the swept forward wing configuration has benefits in both sonic boom reduction and wave drag reduction. The results are validated by using computational fluid dynamics (CFD) analysis.

  10. Research of low boom and low drag supersonic aircraft design

    Directory of Open Access Journals (Sweden)

    Feng Xiaoqiang

    2014-06-01

    Full Text Available Sonic boom reduction will be an issue of utmost importance in future supersonic transport, due to strong regulations on acoustic nuisance. The paper describes a new multi-objective optimization method for supersonic aircraft design. The method is developed by coupling Seebass–George–Darden (SGD inverse design method and multi-objective genetic algorithm. Based on the method, different codes are developed. Using a computational architecture, a conceptual supersonic aircraft design environment (CSADE is constructed. The architecture of CSADE includes inner optimization level and out optimization level. The low boom configuration is generated in inner optimization level by matching the target equivalent area distribution and actual equivalent area distribution. And low boom/low drag configuration is generated in outer optimization level by using NSGA-II multi-objective genetic algorithm to optimize the control parameters of SGD method and aircraft shape. Two objective functions, low sonic boom and low wave drag, are considered in CSADE. Physically reasonable Pareto solutions are obtained from the present optimization. Some supersonic aircraft configurations are selected from Pareto front and the optimization results indicate that the swept forward wing configuration has benefits in both sonic boom reduction and wave drag reduction. The results are validated by using computational fluid dynamics (CFD analysis.

  11. Frente al Envejecimiento en la Mujer

    Directory of Open Access Journals (Sweden)

    Deisy Krzemien

    2007-01-01

    Full Text Available Este trabajo examina la relación entre estilos de personalidad y estilos y estrategias de afrontamiento frente a situaciones críticas del envejecimiento en adultas mayores. Una muestra de 212 participantes fue entrevistada acerca de eventos críticos experimentados en la vejez y evaluada mediante los cuestionarios MIPS y Brief-COPE. La mayoría de los estilos y estrategias de afrontamiento se asoció con determinados estilos de personalidad, en correspondencia a lo esperado según el modelo bipolar de personalidad de Millon. El afrontamiento activo y el apoyo emocional se asociaron positivamente con extraversión, modificación y comunicatividad, y negativamente con retraimiento, acomodación e introversión. El afrontamiento focalizado en el problema se asoció positivamente con intuición, firmeza y control, y negativamente con sensación, vacilación y sometimiento. El afrontamiento evitativo correlacionó positivamente con preservación y negativamente con apertura. Los estilos de personalidad tienen un rol importante en el uso de estrategias de afrontamiento en el envejecimiento femenino.

  12. Empresas familiares frente a las crisis

    Directory of Open Access Journals (Sweden)

    María Guadalupe Serna

    2012-01-01

    Full Text Available En este artículo llevo a cabo una reflexión sobre los efectos de las crisis de 1984-1985 y 1994-1995 en un pequeño grupo de empresas familiares localizadas en la ciudad de Aguascalientes. Exploro el tipo de recursos tangibles e intangibles con los que contaban sus propietarios durante esos periodos, los apoyos que tenían a su disposición, así como las distintas formas en que respondieron y se adaptaron a las condiciones económicas prevalecientes. Analizo las distintas acciones adoptadas por los propietarios para hacer frente a las condiciones económicas prevalecientes, así como la forma en que algunas veces la crisis en puerta impulsó o bien obstaculizó el proyecto empresarial. Para ello empleo el concepto de capital social que resulta de gran utilidad para explicar las diversas condiciones en que surgen y se desarrollan las pequeñas empresas familiares, así como sus distintas posibilidades de éxito en condiciones de crisis.

  13. Lenguas naturales frente a lenguajes artificiales

    Directory of Open Access Journals (Sweden)

    Ramón Trujillo Carreño

    2014-03-01

    Full Text Available Hace ya tiempo que hemos entrado en aquello que Antonio Machado (1936:97 llamaba «ola de ñoñez y de americanismo»1: la trivialización generalizada del saber y de la cultura. Y no es que esa trivialización haya significado nunca ignorancia, sino fundamentalmente la sustitución del humanismo por los métodos de las ciencias físico-matemáticas, entre las cuales se halla la Informática. Hoy «todo se hace científico» en el sentido de sustituir los productos de las culturas tradicionales por complejos «modelos formales», en ese afán por reducirlo todo a fórmulas o a razonamientos matemáticos —o imaginariamente matemáticos—. El humanismo, dentro del que se había situado y desarrollado al menos una parte de la Lingüística, se desacredita2 y se ve como palabrería inútil, frente a la «nueva cientificidad» de quienes ignoran el pensamiento clásico y sus productos fundamentales, como la filosofía o el arte.

  14. Deformation mechanisms in experimentally deformed Boom Clay

    Science.gov (United States)

    Desbois, Guillaume; Schuck, Bernhard; Urai, Janos

    2016-04-01

    Bulk mechanical and transport properties of reference claystones for deep disposal of radioactive waste have been investigated since many years but little is known about microscale deformation mechanisms because accessing the relevant microstructure in these soft, very fine-grained, low permeable and low porous materials remains difficult. Recent development of ion beam polishing methods to prepare high quality damage free surfaces for scanning electron microscope (SEM) is opening new fields of microstructural investigation in claystones towards a better understanding of the deformation behavior transitional between rocks and soils. We present results of Boom Clay deformed in a triaxial cell in a consolidated - undrained test at a confining pressure of 0.375 MPa (i.e. close to natural value), with σ1 perpendicular to the bedding. Experiments stopped at 20 % strain. As a first approximation, the plasticity of the sample can be described by a Mohr-Coulomb type failure envelope with a coefficient of cohesion C = 0.117 MPa and an internal friction angle ϕ = 18.7°. After deformation test, the bulk sample shows a shear zone at an angle of about 35° from the vertical with an offset of about 5 mm. We used the "Lamipeel" method that allows producing a permanent absolutely plane and large size etched micro relief-replica in order to localize and to document the shear zone at the scale of the deformed core. High-resolution imaging of microstructures was mostly done by using the BIB-SEM method on key-regions identified after the "Lamipeel" method. Detailed BIB-SEM investigations of shear zones show the following: the boundaries between the shear zone and the host rock are sharp, clay aggregates and clastic grains are strongly reoriented parallel to the shear direction, and the porosity is significantly reduced in the shear zone and the grain size is smaller in the shear zone than in the host rock but there is no evidence for broken grains. Comparison of microstructures

  15. 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.

  16. 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.

  17. Scattering of sonic booms by anisotropic turbulence in the atmosphere

    Science.gov (United States)

    Kelly; Raspet; Bass

    2000-06-01

    An earlier paper [J. Acoust. Soc. Am. 98, 3412-3417 (1995)] reported on the comparison of rise times and overpressures of sonic booms calculated with a scattering center model of turbulence to measurements of sonic boom propagation through a well-characterized turbulent layer under moderately turbulent conditions. This detailed simulation used spherically symmetric scatterers to calculate the percentage of occurrence histograms of received overpressures and rise times. In this paper the calculation is extended to include distorted ellipsoidal turbules as scatterers and more accurately incorporates the meteorological data into a determination of the number of scatterers per unit volume. The scattering center calculation overpredicts the shifts in rise times for weak turbulence, and still underpredicts the shift under more turbulent conditions. This indicates that a single-scatter center-based model cannot completely describe sonic boom propagation through atmospheric turbulence.

  18. Sonic-boom-induced building structure responses including damage.

    Science.gov (United States)

    Clarkson, B. L.; Mayes, W. H.

    1972-01-01

    Concepts of sonic-boom pressure loading of building structures and the associated responses are reviewed, and results of pertinent theoretical and experimental research programs are summarized. The significance of sonic-boom load time histories, including waveshape effects, are illustrated with the aid of simple structural elements such as beams and plates. Also included are discussions of the significance of such other phenomena as three-dimensional loading effects, air cavity coupling, multimodal responses, and structural nonlinearities. Measured deflection, acceleration, and strain data from laboratory models and full-scale building tests are summarized, and these data are compared, where possible, with predicted values. Damage complaint and claim experience due both to controlled and uncontrolled supersonic flights over communities are summarized with particular reference to residential, commercial, and historic buildings. Sonic-boom-induced building responses are compared with those from other impulsive loadings due to natural and cultural events and from laboratory simulation tests.

  19. 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.

  20. An Experimental Study on the Secondary Deformation of Boom Clay

    OpenAIRE

    2012-01-01

    International audience; Boom clay formation, a deposit of slightly over-consolidated marine clay that belongs to the Oligocene series in the north east of Belgium, has been selected as a possible host material of nuclear waste disposal. In this context, the long-term deformation behaviour of Boom clay is of crucial importance in the performance assessment of the whole storage system. In this study, low and high pressure oedometer tests are carried out; the e-log σ'v (void ratio - logarithm of...

  1. Metering Wheel-Wire Track Wire Boom Deployment Mechanism

    Science.gov (United States)

    Granoff, Mark S.

    2014-01-01

    The NASA MMS Spin Plane Double Probe (SDP) Deployer utilizes a helical path, rotating Metering Wheel and a spring loaded Wire "Holding" Track to pay out a "fixed end" 57 meter x 1.5 mm diameter Wire Boom stored between concentric storage cylinders. Unlike rotating spool type storage devices, the storage cylinders remain stationary, and the boom wire is uncoiled along the length of the cylinder via the rotation of the Metering Wheel. This uncoiling action avoids the need for slip-ring contacts since the ends of the wire can remain stationary. Conventional fixed electrical connectors (Micro-D type) are used to terminate to operational electronics.

  2. CFD prediction of the near-field sonic boom environment for two low boom HSCT configurations. [High Speed Civil Transport

    Science.gov (United States)

    Siclari, M. J.; Darden, C. M.

    1991-01-01

    Current efforts to reduce the sonic boom of a future High Speed Civil Transport (HSCT) by careful shaping have led to the need for more accurate predictions of the near-field flow conditions of the configuration. A fully three-dimensional Euler finite volume code is used to predict sonic boom pressure signatures for two low boom concepts - one designed to cruise at Mach 2 and the other at Mach 3. Calculations were carried out using a grid topology that has been modified to reduce the inaccuracies caused by grid spreading often suffered with CFD methods when calculations several body lengths downstream become necessary. Comparisons of CFD results and experimental wind tunnel signatures are shown. Ground signatures are predicted by extrapolating the pressures predicted by the Euler code with an extrapolation method based on the Whitham theory.

  3. Thermomechanical characterisation of cellular rubber

    Science.gov (United States)

    Seibert, H.; Scheffer, T.; Diebels, S.

    2016-09-01

    This contribution discusses an experimental possibility to characterise a cellular rubber in terms of the influence of multiaxiality, rate dependency under environmental temperature and its behaviour under hydrostatic pressure. In this context, a mixed open and closed cell rubber based on an ethylene propylene diene monomer is investigated exemplarily. The present article intends to give a general idea of the characterisation method and the considerable effects of this special type of material. The main focus lies on the experimental procedure and the used testing devices in combination with the analysis methods such as true three-dimensional digital image correlation. The structural compressibility is taken into account by an approach for a material model using the Theory of Porous Media with additional temperature dependence.

  4. 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.

  5. Prehistoric polymers: rubber processing in ancient mesoamerica

    Science.gov (United States)

    Hosler; Burkett; Tarkanian

    1999-06-18

    Ancient Mesoamerican peoples harvested latex from Castilla elastica, processed it using liquid extracted from Ipomoea alba (a species of morning glory vine), and fashioned rubber balls, hollow rubber figurines, and other rubber artifacts from the resulting material. Chemical and mechanical analyses of the latex and of the processed rubber indicate that the enhanced elastic behavior of the rubber relative to the unprocessed latex is due to purification of the polymer component and to an increase in the strength and number of interchain interactions that are induced by organic compounds present in I. alba. These ancient peoples' control over the properties of latex and processed rubber gave rise to the Mesoamerican ball game, a central ritual element in all ancient Mesoamerican societies.

  6. Impregnation of Natural Rubber into Rubber Wood: A Green Wood Composite

    OpenAIRE

    Wassa Ruayruay; Sureurg Khongtong

    2014-01-01

    A green wood composite material was developed from the two environmentally friendly substrates natural rubber (cis-1,4-polyisoprene) and rubber wood (Hevea brasiliensis). Natural rubber (NR) was introduced into rubber wood by pressurization of NR latex, followed by the removal of the aqueous phase to allow only dry NR to remain inside the wood structure. Scanning electron microscopy images and the weight increase of the dry impregnated samples revealed the retention of dry NR within the rubbe...

  7. VULCANIZATION KINETICS OF SILICONE RUBBER

    Institute of Scientific and Technical Information of China (English)

    YUAN Qiang; LI Yufu; LI Guangliang

    1988-01-01

    Vulcanization rate of silicone rubber with the aid of organic peroxide or hydrosilylation agent was studied by using oscillation disk rheometer. It was found that the process of network formation would take place through one, two or three steps depending on the structure of the reactants. The effect of phenyl group, vinyl terminals on polysiloxane chain and the functionality of silylation agent was also studied.

  8. Chemistry of rubber processing and disposal.

    Science.gov (United States)

    Bebb, R L

    1976-10-01

    The major chemical changes during the processing of rubber occur with the breakdown in mastication and during vulcanization of the molded tire. There is little chemical change during the compounding, calendering, extrusion, and molding steps. Reclaiming is the process of converting scrap rubber into an unsaturated, processible product that can be vulcanized with sulfur. Pyrolysis of scrap rubber yields a complex mixture of liquids, gas, and residue in varying ratios dependent on the nature of the scrap and the conditions of pyrolysis.

  9. Rubber friction: comparison of theory with experiment.

    Science.gov (United States)

    Lorenz, B; Persson, B N J; Dieluweit, S; Tada, T

    2011-12-01

    We have measured the friction force acting on a rubber block slid on a concrete surface. We used both unfilled and filled (with carbon black) styrene butadiene (SB) rubber and have varied the temperature from -10 °C to 100 °C and the sliding velocity from 1 μm/s to 1000 μm/s. We find that the experimental data at different temperatures can be shifted into a smooth master-curve, using the temperature-frequency shifting factors obtained from measurements of the bulk viscoelastic modulus. The experimental data has been analyzed using a theory which takes into account the contributions to the friction from both the substrate asperity-induced viscoelastic deformations of the rubber, and from shearing the area of real contact. For filled SB rubber the frictional shear stress σ(f) in the area of real contact results mainly from the energy dissipation at the opening crack on the exit side of the rubber-asperity contact regions. For unfilled rubber we instead attribute σ(f) to shearing of a thin rubber smear film, which is deposited on the concrete surface during run in. We observe very different rubber wear processes for filled and unfilled SB rubber, which is consistent with the different frictional processes. Thus, the wear of filled SB rubber results in micrometer-sized rubber particles which accumulate as dry dust, which is easily removed by blowing air on the concrete surface. This wear process seams to occur at a steady rate. For unfilled rubber a smear film forms on the concrete surface, which cannot be removed even using a high-pressure air stream. In this case the wear rate appears to slow down after some run in time period.

  10. Studies to Improve Environmental Assessments of Sonic Booms Produced during Air Combat Maneuvering

    Science.gov (United States)

    1983-10-01

    aircraft longitudinal acceleration, (3) Lateral Cutoff booms - commonly heard as a low frequency rumble at ground locations near the edges of the boom...analyzed in this study. The booms corresponding to categories (1) and (2) occurred with aircraft longitudinal accelerations between about 3.7 to 5.1

  11. 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.

  12. Malaria-associated rubber plantations in Thailand.

    Science.gov (United States)

    Bhumiratana, Adisak; Sorosjinda-Nunthawarasilp, Prapa; Kaewwaen, Wuthichai; Maneekan, Pannamas; Pimnon, Suntorn

    2013-01-01

    Rubber forestry is intentionally used as a land management strategy. The propagation of rubber plantations in tropic and subtropic regions appears to influence the economical, sociological and ecological aspects of sustainable development as well as human well-being and health. Thailand and other Southeast Asian countries are the world's largest producers of natural rubber products; interestingly, agricultural workers on rubber plantations are at risk for malaria and other vector-borne diseases. The idea of malaria-associated rubber plantations (MRPs) encompasses the complex epidemiological settings that result from interactions among human movements and activities, land cover/land use changes, agri-environmental and climatic conditions and vector population dynamics. This paper discusses apparent issues pertaining to the connections between rubber plantations and the populations at high risk for malaria. The following questions are addressed: (i) What are the current and future consequences of rubber plantations in Thailand and Southeast Asia relative to malaria epidemics or outbreaks of other vector-borne diseases? (ii) To what extent is malaria transmission in Thailand related to the forest versus rubber plantations? and (iii) What are the vulnerabilities of rubber agricultural workers to malaria, and how contagious is malaria in these areas?

  13. Inclined boom system with hydrofoil for waters with waves

    Energy Technology Data Exchange (ETDEWEB)

    Wong, K.V.; Miller, M.K.; Boccabella, A. [Miami Univ., Coral Gables, FL (United States)

    2005-07-01

    It is inevitable that spills and accidental discharges of oil will occur while transporting oil in tanker ships. Although marine oil spills have been reduced due to doubled hulled tankers and environmental regulations, oil spills still present a threat to bays, shorelines and marine life. Therefore, oil response must be rapid, effective and thorough. An innovative oil containment boom that can collect oil in waters with waves was designed and constructed. Booms contain the spread of oil after a spill and also concentrate oil into thicker layers, making recovery more effective. They can be used to direct and channel oil slicks along desired paths into skimming equipment. This newly designed boom includes a ramp placed at an angle of 12 degrees from the horizontal. Three collection zones are used in which oil is pumped out to an oil storage tank. The design incorporates a hydrofoil for stability. The hydrofoil counteracts the lift created by the ramp. Results show that the hydrofoils were effective at high flow rates and waves. At low flow rates, the boom units relied mostly on the Styrofoam flotation devices for stability. For experiments without waves, the collection efficiency ranged from 95.9 per cent to 99.6 per cent. At least 3 forward waves were created for the high and intermediate velocities. Five forward waves were created at the low velocity. The collection efficiency ranged from 51.7 per cent to 69.3 per cent. 14 refs., 2 tabs., 10 figs.

  14. Applied and fundamental aspects of BABY BOOM-mediated regeneration

    NARCIS (Netherlands)

    Heidmann, I.A.

    2015-01-01

    Keywords: Somatic embryogenesis, Transcription factor, AINTEGUMENTA-LIKE, BABY BOOM, BBM, Sweet Pepper Transformation Title: Applied and Fundamental Aspects of BBM-mediated Regeneration Author: Iris Heidmann Catergories: Plant regeneration, Plant

  15. The Baby Boom and the Baby Boomette: Two Different Eras.

    Science.gov (United States)

    Caffarella, Edward P.

    1987-01-01

    The "baby boomette," occurring since 1973, differs from the earlier "baby boom" in that the maximum number of births, the rate of growth, and the size of the yearly increase will all be less. Also, the rate of decline will be slower and the length of the boomette will be shorter. (MLF)

  16. Retirement Prospects of the Baby Boom Generation: A Different Perspective.

    Science.gov (United States)

    Easterlin, Richard A.; And Others

    1990-01-01

    Examined average economic status of baby boom cohorts as they approach retirement using data on their life cycle income experience. Findings suggest that baby boomers are likely to enter old age in better economic position than preboom cohorts because of deferred marriages, reduced childbearing, and increased labor force participation of wives…

  17. The Baby Boom Echo: Implications for School Enrollments and Programs.

    Science.gov (United States)

    ERS Spectrum, 1996

    1996-01-01

    Based on NCES statistics, the school-age population (the baby boom echo) will pose major challenges for education. Between 1996 and 2006, total public and private school enrollment will rise from a record 51.7 million to 54.6 million. The nation will need 190,000 additional teachers, 6,000 more schools, and $15 billion in additional annual…

  18. Influence of crumb rubber and digestion time on the asphalt rubber binders

    OpenAIRE

    Neto, Silvrano Adonias Dantas; De Farias, Márcio Muniz; Pais, Jorge C.; Pereira, Paulo A. A.; Sousa, Jorge B.

    2006-01-01

    This paper shows the results of a study about the mechanical behavior of dense graded asphalt-rubber hot mixes prepared with two different types of asphalt-rubber binders. These asphalt-rubber binders were obtained with penetration grade asphalt (AC 50/70) mixed with 21% and 25% of crumb rubber in weight. The rubber was recycled from unserviceable tires using the ambient grinding process. Hot mixes made with the conventional binder AC 50/70 were also studied for comparison. The...

  19. EPDM Rubber Reclaim from Devulcanized EPDM

    NARCIS (Netherlands)

    Sutanto, P.; Picchioni, F.; Janssen, L.P.B.M.; Dijkhuis, K.A.J.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2006-01-01

    Two types of ethylene-propylene-diene monomer (EPDM) rubbers, namely an efficient vulcanized (EV) and a semiefficient vulcanized (SEV), have been used to produce devulcanizates in a continuous setup. The devulcanizates are re-cured using the same recipes as for the virgin rubber. The influence of

  20. EPDM rubber reclaim from devulcanized EPDM

    NARCIS (Netherlands)

    Sutanto, P.; Picchioni, F.; Janssen, L. P. B. M.; Dijkhuis, K. A. J.; Dierkes, W. K.; Noordermeer, J. W. M.

    2006-01-01

    Two types of ethylene-propylene-diene monomer (EPDM) rubbers, namely an efficient vulcanized (EV) and a serniefficient vulcanized (SEV), have been used to produce devulcanizates in a continuous setup. The devulcanizates are re-cured using the same recipes as for the virgin rubber. The influence of

  1. Unraveling the Mystery of Natural Rubber Biosynthesis

    Science.gov (United States)

    Natural rubber (NR) is primarily obtained from Hevea brasiliensis, commonly known as the Brazilian rubber tree. As this species contains little genetic variation, it is susceptible to pathogen-based eradication. Consequently, it is imperative that a biomimetic pathway for NR production be developed....

  2. EPDM rubber reclaim from devulcanized EPDM

    NARCIS (Netherlands)

    Sutanto, P.; Picchioni, F.; Janssen, L. P. B. M.; Dijkhuis, K. A. J.; Dierkes, W. K.; Noordermeer, J. W. M.

    2006-01-01

    Two types of ethylene-propylene-diene monomer (EPDM) rubbers, namely an efficient vulcanized (EV) and a serniefficient vulcanized (SEV), have been used to produce devulcanizates in a continuous setup. The devulcanizates are re-cured using the same recipes as for the virgin rubber. The influence of m

  3. Biorefinery of proteins from rubber plantation residues

    NARCIS (Netherlands)

    Widyarani, R.

    2016-01-01

    Biorefinery of rubber tree side streams could add economic value and income for farmers, who already grow the trees for latex production. The objective of this research was to design a process for the recovery of proteinaceous fractions from rubber tree. The aimed applications were expected to be su

  4. 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...

  5. Biorefinery of proteins from rubber plantation residues

    NARCIS (Netherlands)

    Widyarani, R.

    2016-01-01

    Biorefinery of rubber tree side streams could add economic value and income for farmers, who already grow the trees for latex production. The objective of this research was to design a process for the recovery of proteinaceous fractions from rubber tree. The aimed applications were expected to be su

  6. Better Tomorrow of China Rubber Chemicals Industry

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    I. Development of China Rubber Chemicals Industry During the "11th Five-Year Plan" period, China rubber Chemicals industry fully implemented the development guideline of "Adhering to science and technology development, developing green chemistry with environmental protection, safety and energy conservation as the core, and building enterprise and world brands". With the great support of the state,

  7. Zinc leaching from tire crumb rubber.

    Science.gov (United States)

    Rhodes, Emily P; Ren, Zhiyong; Mays, David C

    2012-12-04

    Because tires contain approximately 1-2% zinc by weight, zinc leaching is an environmental concern associated with civil engineering applications of tire crumb rubber. An assessment of zinc leaching data from 14 studies in the published literature indicates that increasing zinc leaching is associated with lower pH and longer leaching times, but the data display a wide range of zinc concentrations, and do not address the effect of crumb rubber size or the dynamics of zinc leaching during flow through porous crumb rubber. The present study was undertaken to investigate the effect of crumb rubber size using the synthetic precipitation leaching procedure (SPLP), the effect of exposure time using quiescent batch leaching tests, and the dynamics of zinc leaching using column tests. Results indicate that zinc leaching from tire crumb rubber increases with smaller crumb rubber and longer exposure time. Results from SPLP and quiescent batch leaching tests are interpreted with a single-parameter leaching model that predicts a constant rate of zinc leaching up to 96 h. Breakthrough curves from column tests displayed an initial pulse of elevated zinc concentration (~3 mg/L) before settling down to a steady-state value (~0.2 mg/L), and were modeled with the software package HYDRUS-1D. Washing crumb rubber reduces this initial pulse but does not change the steady-state value. No leaching experiment significantly reduced the reservoir of zinc in the crumb rubber.

  8. Amino acid modifiers in guayule rubber compounds

    Science.gov (United States)

    Tire producers are increasingly interested in biobased materials, including rubber but also as compounding chemicals. An alternative natural rubber for tire use is produced by guayule, a woody desert shrub native to North America. Alternative compounding chemicals include naturally-occurring amino a...

  9. Estimation of genetic parameters in rubber progenies

    Directory of Open Access Journals (Sweden)

    Cecília Khusala Verardi

    2012-09-01

    Full Text Available This study was designed to evaluate the genetic variability, the potential for rubber yield and secondary traits of rubber tree progenies at three locations in the state of Sao Paulo. The experiments were conducted in a randomized block design with 22 progenies and 6 replications. At the age of three years, the progenies were evaluated for rubber yield, girth growth and total number of latex vessel rings. The results showed the existence of genetic variability among progenies for each location separately as well as between locations, with differences in the progeny performance for the traits. The individual heritabilities calculated for rubber yield, girth growth and total number of latex vessel rings (0.30, 0.63 and 0.29, respectively, associated with high genetic gains with selection for the traits studied at each site, showed that the populations can be considered suitable for the rubber breeding program, provided that an appropriate selection procedure is used.

  10. Lignocellulosic fiber reinforced rubber composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available stream_source_info John_d1_2009.pdf.txt stream_content_type text/plain stream_size 43167 Content-Encoding UTF-8 stream_name John_d1_2009.pdf.txt Content-Type text/plain; charset=UTF-8 -252- CHAPTER 10: LIGNOCELLULOSIC... FIBER REINFORCED RUBBER COMPOSITES Maya JACOB JOHN1 Rajesh D. ANANDJIWALA2 (1)CSIR Materials Science and Manufacturing, Fibres and Textiles Competence Area, P.O. Box 1124, Port Elizabeth 6000, South Africa, E-mail: mjohn@csir.co.za (2) Department...

  11. Grenville Zircon Fertility, Baby Boom, and Baby Boom Echo; Natural Bias in the Detrital Zircon Record

    Science.gov (United States)

    Moecher, D. P.; Samson, S. D.

    2006-12-01

    Grenville-aged (~1150-1050 Ma) granitoids of eastern Laurentia exposed in Appalachian basement massifs are as much as 20 times more Zr-rich and much more fertile for crystallizing zircon compared to Paleozoic Laurentian granitoids of the Eastern Blue Ridge, Inner Piedmont, and Carolina terranes. Erosion of Grenville source rocks generates disproportionately large numbers and/or sizes of detrital zircon compared to less fertile magmatic sources. The latter are essentially undetectable by standard detrital zircon provenance methods (SHRIMP or LA-ICP-MS analysis of magmatic cores of >100 micron grains). Grenvillian zircon fertility biased the Neoproterozoic to Recent detrital record as a result of: (1) zircon durability and insolubility in aqueous fluids means detrital zircons eroded from Grenville basement terranes are recycled during repeated orogenesis; (2) inertness of zircon below upper amphibolite facies (onset of anatexis), and high Zr resulting from concentration of detrital zircon in sedimentary protoliths, means dominantly metasedimentary terranes will fail to generate sufficient new zircon corresponding in age to the time of accretion of those terranes to Laurentia. Zircon growth under incipient anatectic conditions generates new zircon as overgrowths on detrital magmatic cores; overgrowths are often too thin to analyze by ion or laser beam. In this case, metasedimentary terranes may be rendered essentially undetectable. New `magmatic' zircon may be generated with greater degrees of anatexis, but might be inferred to be of plutonic, not metamorphic, parentage. Grenville modes dominate detrital zircon age distributions for: Laurentian Neoproterozoic rift basins; Neoproterozoic to Lower Ordovician passive margin sequences; Appalachian Paleozoic syn-orogenic clastic sequences; Appalachian metasedimentary terranes; and modern rivers. The latter is surprising since Grenville terranes comprise baby boom' that echoed through later orogenies. The natural Grenville

  12. 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.

  13. Extraction and characterization of latex and natural rubber from rubber-bearing plants.

    Science.gov (United States)

    Buranov, Anvar U; Elmuradov, Burkhon J

    2010-01-27

    Consecutive extraction of latex and natural rubber from the roots of rubber-bearing plants such as Taraxacum kok-saghyz (TKS), Scorzonera tau-saghyz (STS), and Scorzonera Uzbekistanica (SU) were carried out. Latex extraction was carried via two methods: Blender method and Flow method. The results of latex extraction were compared. Cultivated rubber-bearing plants contained slightly higher latex contents compared to those from wild fields. Several creaming agents for latex extraction were compared. About 50% of total natural rubber was extracted as latex. The results of the comparative studies indicated that optimum latex extraction can be achieved with Flow method. The purity of latex extracted by Blender method ( approximately 75%) was significantly lower than that extracted by Flow method (99.5%). When the latex particles were stabilized with casein, the latex was concentrated significantly. Through concentrating latex by flotation, the latex concentration of 35% was obtained. Bagasse contained mostly solid natural rubber. The remaining natural rubber in the bagasse (left after the latex extraction) was extracted using sequential solvent extraction first with acetone and then with several nonpolar solvents. Solid natural rubber was analyzed for gel content and characterized by size exclusion chromatography (SEC) for molecular weight determinations. SEC of solid natural rubber has shown that the molecular weight is about 1.8E6 and they contain less gel compared to TSR20 (Grade 20 Technically Specified Rubber), a commercial natural rubber from Hevea brasiliensis.

  14. Active control of road booming noise in automotive interiors.

    Science.gov (United States)

    Oh, Shi-Hwan; Kim, Hyoun-suk; Park, Youngjin

    2002-01-01

    An active feedforward control system has been developed to reduce the road booming noise that has strong nonlinear characteristics. Four acceleration transducers were attached to the suspension system to detect reference vibration and two loudspeakers were used to attenuate the noise near the headrests of two front seats. A leaky constraint multiple filtered-X LMS algorithm with an IIR-based filter that has fast convergence speed and frequency selective controllability was proposed to increase the control efficiency in computing power and memory usage. During the test drive on the rough asphalt and turtle-back road at a constant speed of 60 km/h, we were able to achieve a reduction of around 6 dB of A-weighted sound pressure level in the road booming noise range with the proposed algorithm, which could not be obtained with the conventional multiple filtered-X LMS algorithm.

  15. Sonic Boom Mitigation Through Aircraft Design and Adjoint Methodology

    Science.gov (United States)

    Rallabhandi, Siriam K.; Diskin, Boris; Nielsen, Eric J.

    2012-01-01

    This paper presents a novel approach to design of the supersonic aircraft outer mold line (OML) by optimizing the A-weighted loudness of sonic boom signature predicted on the ground. The optimization process uses the sensitivity information obtained by coupling the discrete adjoint formulations for the augmented Burgers Equation and Computational Fluid Dynamics (CFD) equations. This coupled formulation links the loudness of the ground boom signature to the aircraft geometry thus allowing efficient shape optimization for the purpose of minimizing the impact of loudness. The accuracy of the adjoint-based sensitivities is verified against sensitivities obtained using an independent complex-variable approach. The adjoint based optimization methodology is applied to a configuration previously optimized using alternative state of the art optimization methods and produces additional loudness reduction. The results of the optimizations are reported and discussed.

  16. Baby booms, busts, and population ageing in the developed world.

    Science.gov (United States)

    Reher, David S

    2015-01-01

    The key challenge facing contemporary society is a process of population ageing rooted mainly in past fertility cycles. The goals of the study reported in this paper were (i) to analyse jointly the post-1930s baby boom and the baby bust that followed, (ii) to consider the specific ways this particular combination influenced the process of ageing in different societies, and (iii) to evaluate some possible implications for policy of different historical experiences. Demographic time series for 27 nations in the developed world were used. The main results confirm the importance of the boom and bust fertility cycle of the second half of the twentieth century for population ageing. Some countries will experience ageing processes driven mainly by the growth of elderly populations while others will age largely as a result of declines in working-age populations. These differences underscore the need to tailor policy priorities for specific patterns of ageing.

  17. Cerveza artesanal : El boom que no para de crecer

    OpenAIRE

    Revista Institucional de la Facultad de Ciencias Económicas

    2015-01-01

    El boom de la cervecería artesanal, que comenzó en Mar del Plata hace ya más de una década, ha tenido un importante epicentro en la ciudad de La Plata, donde la demanda aún supera por amplio margen a la oferta de un mercado en pleno crecimiento. Facultad de Ciencias Económicas

  18. Cerveza artesanal : El boom que no para de crecer

    OpenAIRE

    Revista Institucional de la Facultad de Ciencias Económicas

    2015-01-01

    El boom de la cervecería artesanal, que comenzó en Mar del Plata hace ya más de una década, ha tenido un importante epicentro en la ciudad de La Plata, donde la demanda aún supera por amplio margen a la oferta de un mercado en pleno crecimiento. Facultad de Ciencias Económicas

  19. Research of low boom and low drag supersonic aircraft design

    OpenAIRE

    Feng Xiaoqiang; Li Zhanke; Song Bifeng

    2014-01-01

    Sonic boom reduction will be an issue of utmost importance in future supersonic transport, due to strong regulations on acoustic nuisance. The paper describes a new multi-objective optimization method for supersonic aircraft design. The method is developed by coupling Seebass–George–Darden (SGD) inverse design method and multi-objective genetic algorithm. Based on the method, different codes are developed. Using a computational architecture, a conceptual supersonic aircraft design environment...

  20. How to Develop Rubber Production in Xishuangbanna Dai Autonomous Prefecture?

    Institute of Scientific and Technical Information of China (English)

    Huide; HUANG; Haolun; HUANG; Wanzhen; ZHANG

    2015-01-01

    The natural rubber planting area in Xishuangbanna Dai Autonomous Prefecture accounts for about 30% of rubber planting area in China. At the end of 2013,the rubber planting area in Xishuangbanna Dai Autonomous Prefecture was 29. 4 ha,the tapped rubber plantation area was 17. 49 ha,and the dry rubber production was 317000 t. Currently,the production and management level of rubber plantation has declined in Xishuangbanna Dai Autonomous Prefecture,the tapping technique is outdated,and the tapping technology management system is difficult to implement. Therefore,some ways can be employed to promote the development of rubber industry such as enhancing the operation and management level of rubber industry,organizing the rubber production team,and developing the new rubber farmers’ cooperatives.

  1. Support for baby-boom retirees--not to worry.

    Science.gov (United States)

    Vatter, H G; Walker, J F

    1998-03-01

    Flaws in the discussion of the baby-boom retiree problem make the Social Security problem seem worse than it really is. Problems include the overwhelming emphasis upon fiscal and related financial aspects at the expense of consideration of the output of goods and services, and the almost total neglect of projected real income and productivity rises. Rather, baby-boom retirees can be coped with on the basis of hypothetically reasonable projected magnitudes. It is currently being argued that the future US economy cannot provide Social Security support for the upcoming baby-boom retirees. However, people who support such an argument fail to consider the main determinant of capacity to support. That determinant is the historically established rise in productivity as expressed in per capita output or output per hour of the employed population. Maintaining Social Security pension support through 2030 involves little to no strain upon society, while abolishing such support would cause considerable strain. The authors describe who Social Security supports now and in the future, and explain the capacity of US society to fund Social Security in the decades ahead.

  2. Boom accomodation effects on plasma and field measurements with RPWI

    Science.gov (United States)

    Cervantes Correa, P.; Eriksson, A. I.; Wahlund, J.-E.; Odelstad, E.; Vaivads, A.; Bergman, J.

    2013-09-01

    While the JUICE spacecraft configuration and main contractor are yet to be decided, it is still possible to investigate general issues on the impact of various boom accomodation alternatives for measurements of plasma and electric fields using the Langmuir probe system of the Radio and Plasma Waves Investigation. These probes can be used as classical Langmuir probes, as electric field probes, or for mutual impedance measurements, and the impact of e.g. varying illumination and wake interference are different for each type of measurement. While there is a nominal JUICE trajectory for the main science mission, we have to do assumptions on the spacecraft pointing, e.g. nadir pointing during flybys of the various moons. The detailed spacecraft layout is not known, but we can arrive at general conclusions on the suitability of various boom accomodations by assuming a cube-like spacecraft with solar panels as rectangular wings. For disturbing structures like wakes and photoelectron clouds we use simple models based on previous simulations. Even though the detailed pointing and spacecraft design will quite certainly deviate from our assumptions, and the model has uncertainties also in other respects, we can still give some general conclusions on boom accomodation alternatives.

  3. 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.

  4. 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.

  5. History of Rubber and Its Use

    Science.gov (United States)

    Müller, Ingo; Strehlow, Peter

    Despite its spectacular properties rubber was not much good for anything before the latter part of the 19th century. To be sure the Aztecs had used it to make balls for their ceremonial ball games - or so we are told. But those games died along with the Aztec culture in the 16th century and there is no record of other useful applications until the late 18th century. But then, after that, rubber took off in a small way. After the American inventor Samuel Peal had obtained a patent in 1791 for the production of rubber-coated watertight textiles, the Scottish chemist Charles Macintosh (1766-1843) used such textiles for making rain-coats, and Thomas Hancock (1786-1865) produced rubber boots. At that time it was not really appropriate to speak of a rubber industry. What little material the evil-smelling workshops in New York and London needed, could be satisfied with the import of 30 tons of Caoutchouc1 annually - extracted from the sap of the tree Hevea brasiliensis - and most of that went for making erasers. Indeed, it had been reported by the English minister and scientist Joseph Priestley (1733-1804) that pieces of rubber are well-suited to rub out (sic!) pencil marks. Even today there is nothing better for the purpose and rubber became the English word for Caoutchouc.

  6. Polypropylene–rubber blends: 2. The effect of the rubber content on the deformation and impact behaviour

    NARCIS (Netherlands)

    Wal, van der A.; Nijhof, R.; Gaymans, R.J.

    1999-01-01

    The effect of the rubber content on the deformation and impact behaviour of polypropylene–EPDM rubber blends is studied. The blends are made on a twin screw extruder. The rubber content ranged from 0 to 40 vol.%. The tensile modulus and the yield stress decrease linearly with increasing rubber conte

  7. Effect of Rubberized Bitumen Blending Methods on Permanent Deformation of SMA Rubberized Asphalt Mixtures

    Directory of Open Access Journals (Sweden)

    Herda Yati Katman

    2016-01-01

    Full Text Available This study aims at comparing the permanent deformation of Stone Mastic Asphalt (SMA rubberized asphalt mixtures produced by the wet process. In this study, rubberized binders were prepared using two different blending methods, namely, continuous blend and terminal blend. To study the creep behaviour of control and rubberized asphalt mixtures, the dynamic creep test was performed using Universal Materials Testing Apparatus (UMATTA at different temperatures and stress levels. Zhou three-stage creep model was utilized to evaluate the deformation characteristics of the mixtures. In all test conditions, the highest resistance to permanent deformation is showed by the rubberized mixtures produced with continuous blend binders. This study also reveals that the permanent deformation of rubberized mixtures cannot be predicted based on the characteristics of the rubberized binders.

  8. 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.

  9. 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.

  10. Properties of Nanokaolin and Its Rubber Composites

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-de; LIU Qin-fu; JI Lei-bo; LU Yin-ping

    2005-01-01

    A kind of nanokaolin powder with a thickness of 20-50nm and an average diameter of 300nm is produced through combined procedure of purification, delamination, surface modification and pulverization. The application experiments in butadiene rubber (BR), ethylene-propylene diene methylene (EPDM), and natural rubber (NR) indicates that this nano-kaolin powder material is much better than precipitated silica in reinforcement, while in styrene-butadiene rubber (SBR) it is close to precipitated silica. Nanokaolin is of superiority in elasticity, elongation at break, anti-flexure property.

  11. 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....

  12. Chemistry of rubber processing and disposal.

    Science.gov (United States)

    Bebb, R L

    1976-01-01

    The major chemical changes during the processing of rubber occur with the breakdown in mastication and during vulcanization of the molded tire. There is little chemical change during the compounding, calendering, extrusion, and molding steps. Reclaiming is the process of converting scrap rubber into an unsaturated, processible product that can be vulcanized with sulfur. Pyrolysis of scrap rubber yields a complex mixture of liquids, gas, and residue in varying ratios dependent on the nature of the scrap and the conditions of pyrolysis. PMID:799964

  13. Suitability of rubber concrete for railway sleepers

    Directory of Open Access Journals (Sweden)

    Afia S. Hameed

    2016-09-01

    Full Text Available An experimental investigation by replacing 15% by volume fraction of fine aggregate by crumb rubber was conducted to find the fatigue failure load and impact resistance. The design strength of 50 and 55 MPa was achieved. Test result indicated that there was reduction in compressive strength and modulus values. The fatigue failure and impact resistance were high for rubber concrete when compared with ordinary high strength concrete. The impact strength for railway sleeper with crumb rubber replacement showed increase of about 60% when compared to prestressed concrete sleeper.

  14. Material Model Research on Rubber Vibration Isolators

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A viscohyperelastic constitutive model is proposed to describe the mechanical behaviour of vibration isolation rubber under broad-band vibration. This constitutive model comprises two parts: a component with three parameters to characterize the hyperelastic static properties of rubber materials,and the other component incorporating two relaxation time parameters, corresponding to high and low strain rates, respectively, to describe the dynamic response under vibration and impact loadings. Based on this proposed constitutive model, a series of experiments were performed on two types of rubber materials over a wide strain rate range. The results predicted from this model are in good agreement with the experimental data.

  15. An interactive web-based design system for rubber injection mold: Automotive rubber parts

    OpenAIRE

    Chamnarn Thongmark; Jariyaporn Onwong

    2016-01-01

    This research aims at integrating a knowledge-based system and web-based technology to facilitate the rubber and rubber composite injection mold design. The system integrates both of computer-aided design and web-based management by using the application programming interface. The research processes started with gathering data and knowledge concerning on rubber injection mold design and process, with the designed framework of the system included. An example part was demonstrated i...

  16. An interactive web-based design system for rubber injection mold: Automotive rubber parts

    OpenAIRE

    Chamnarn Thongmark; Jariyaporn Onwong

    2016-01-01

    This research aims at integrating a knowledge-based system and web-based technology to facilitate the rubber and rubber composite injection mold design. The system integrates both of computer-aided design and web-based management by using the application programming interface. The research processes started with gathering data and knowledge concerning on rubber injection mold design and process, with the designed framework of the system included. An example part was demonstrated i...

  17. Micromorphological characterization and label-free quantitation of small rubber particle protein in natural rubber latex.

    Science.gov (United States)

    Wang, Sai; Liu, Jiahui; Wu, Yanxia; You, Yawen; He, Jingyi; Zhang, Jichuan; Zhang, Liqun; Dong, Yiyang

    2016-04-15

    Commercial natural rubber is traditionally supplied by Hevea brasiliensis, but now there is a big energy problem because of the limited resource and increasing demand. Intensive study of key rubber-related substances is urgently needed for further research of in vitro biosynthesis of natural rubber. Natural rubber is biosynthesized on the surface of rubber particles. A membrane protein called small rubber particle protein (SRPP) is a key protein associated closely with rubber biosynthesis; however, SRPP in different plants has been only qualitatively studied, and there are no quantitative reports so far. In this work, H. brasiliensis was chosen as a model plant. The microscopic distribution of SRPP on the rubber particles during the washing process was investigated by transmission electron microscopy-immunogold labeling. A label-free surface plasmon resonance (SPR) immunosensor was developed to quantify SRPP in H. brasiliensis for the first time. The immunosensor was then used to rapidly detect and analyze SRPP in dandelions and prickly lettuce latex samples. The label-free SPR immunosensor can be a desirable tool for rapid quantitation of the membrane protein SRPP, with excellent assay efficiency, high sensitivity, and high specificity. The method lays the foundation for further study of the functional relationship between SRPP and natural rubber content.

  18. Characterization of rubber particles and rubber chain elongation in Taraxacum koksaghyz

    Directory of Open Access Journals (Sweden)

    Prüfer Dirk

    2010-02-01

    Full Text Available Abstract Background Natural rubber is a biopolymer with exceptional qualities that cannot be completely replaced using synthetic alternatives. Although several key enzymes in the rubber biosynthetic pathway have been isolated, mainly from plants such as Hevea brasiliensis, Ficus spec. and the desert shrub Parthenium argentatum, there have been no in planta functional studies, e.g. by RNA interference, due to the absence of efficient and reproducible protocols for genetic engineering. In contrast, the Russian dandelion Taraxacum koksaghyz, which has long been considered as a potential alternative source of low-cost natural rubber, has a rapid life cycle and can be genetically transformed using a simple and reliable procedure. However, there is very little molecular data available for either the rubber polymer itself or its biosynthesis in T. koksaghyz. Results We established a method for the purification of rubber particles - the active sites of rubber biosynthesis - from T. koksaghyz latex. Photon correlation spectroscopy and transmission electron microscopy revealed an average particle size of 320 nm, and 13C nuclear magnetic resonance (NMR spectroscopy confirmed that isolated rubber particles contain poly(cis-1,4-isoprene with a purity >95%. Size exclusion chromatography indicated that the weight average molecular mass (w of T. koksaghyz natural rubber is 4,000-5,000 kDa. Rubber particles showed rubber transferase activity of 0.2 pmol min-1 mg-1. Ex vivo rubber biosynthesis experiments resulted in a skewed unimodal distribution of [1-14C]isopentenyl pyrophosphate (IPP incorporation at a w of 2,500 kDa. Characterization of recently isolated cis-prenyltransferases (CPTs from T. koksaghyz revealed that these enzymes are associated with rubber particles and are able to produce long-chain polyprenols in yeast. Conclusions T. koksaghyz rubber particles are similar to those described for H. brasiliensis. They contain very pure, high molecular mass

  19. Using CFD Surface Solutions to Shape Sonic Boom Signatures Propagated from Off-Body Pressure

    Science.gov (United States)

    Ordaz, Irian; Li, Wu

    2013-01-01

    The conceptual design of a low-boom and low-drag supersonic aircraft remains a challenge despite significant progress in recent years. Inverse design using reversed equivalent area and adjoint methods have been demonstrated to be effective in shaping the ground signature propagated from computational fluid dynamics (CFD) off-body pressure distributions. However, there is still a need to reduce the computational cost in the early stages of design to obtain a baseline that is feasible for low-boom shaping, and in the search for a robust low-boom design over the entire sonic boom footprint. The proposed design method addresses the need to reduce the computational cost for robust low-boom design by using surface pressure distributions from CFD solutions to shape sonic boom ground signatures propagated from CFD off-body pressure.

  20. Statistical and numerical study of the relation between weather and sonic boom characteristics

    Science.gov (United States)

    Yao, Lixin; Bass, Henry E.; Raspet, Richard; McBride, Walton E.

    1992-04-01

    NASA measured sonic boom characteristics near Edwards Air Force Base from 11/66 to 1/67. Thirty four flights by an F-104 were recorded at an altitude of about 31,000 feet and flying speed of Mach 1.3. Forty two microphones were placed on the ground directly under the fight track. Each microphone recorded boom shape, rise time, peak overpressure, total boom duration, positive duration, and positive impulse.

  1. Visual evoked potentials in rubber factory workers.

    Science.gov (United States)

    Tandon, O P; Kumar, V

    1997-01-01

    Pattern reversal visual evoked potentials (pVEP) were studied in 39 male rubber factory workers in the age range of 18-55 years and 20 control subjects (aged 18-46 years) not exposed to the rubber factory environment. Results revealed that 20 (51%) rubber factory workers had abnormal latencies of wave P1 (dominant component of pVEP) as per accepted criteria of 99% tolerance limit set for the control group (i.e. any value above mean +3 SD of control was considered abnormal). The section-wise per cent distribution of abnormalities was vulcanization (83%), tubing (75%), calendering (60%), loading (38%) and mixing (14%). This study provides electrophysiological evidence that rubber factory environments affect the conduction processes in optical pathways from their origin in the retina to striate cortex. However, this study has its limitations in not identifying the specific chemical(s) causing these changes in VEP.

  2. Oils and rubber from arid land plants

    Science.gov (United States)

    Johnson, J. D.; Hinman, C. W.

    1980-05-01

    In this article the economic development potentials of Cucurbita species (buffalo gourd and others), Simmondsia chinensis (jojoba), Euphorbia lathyris (gopher plant), and Parthenium argentatum (guayule) are discussed. All of these plants may become important sources of oils or rubber.

  3. Contact allergy to rubber accelerators remains prevalent

    DEFF Research Database (Denmark)

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

    2016-01-01

    INTRODUCTION: Chemicals used for the manufacturing of rubber are known causes of allergic contact dermatitis on the hands. Recent European studies have suggested a decrease in thiuram contact allergy. Moreover, while an association with hand dermatitis is well established, we have recently observ.......2% (19/54) and 35.4% (17/48) of the cases respectively. CONCLUSION: Contact allergy to rubber accelerators remains prevalent. Clinicians should be aware of the hitherto unexplored clinical association with facial dermatitis....

  4. THERMAL CONDUCTIVITY OF RUBBERIZED GYPSUM BOARD

    OpenAIRE

    Taher Abu-Lebdeh; Ellie Fini; Ashraf Fadiel

    2014-01-01

    The disposal of scrap tires is a challenging task and hence an innovative solution to meet these challenges is needed. Extensive work has been done on the utilization of waste tires in a variety of applications in asphalt pavements and concrete. However, previous investigations focus only on the mechanical properties of the rubberized materials, but few on the thermal performance. This is especially true for rubberized gypsum. Limited or no experimental data on the thermal performance of rubb...

  5. Rubber-Modified Epoxies: Transitions and Morphology.

    Science.gov (United States)

    1980-09-01

    temperatures used for cure (i.e. Tso > Tcure). A low molecular weight liquid diglycidyl ether of bisphenol A ( DGEBA ) epoxy resin, Epon 828, Shell Chemical Co...the rubber damping peak always occurs at or below the Tg of unreacted CTBN even though CTBN is capped with DGEBA (see Ref. 5 which also shows that the...depression of RTg decreases with increasing amounts of rubber modifier in the formulations). DGEBA and CTBN must be incorporated in the domains since

  6. [Detection of pentachlorophenol in natural rubber latex].

    Science.gov (United States)

    Jaworska, E

    1976-01-01

    The method of detection of pentachlorophenol in natural rubber latex is proposed. Pentachlorophenol is isolated from other nonrubber-like substances by thin-layer chromatography and identified by spectroscopic method in UV-light. Isolation of pentachlorophenol is carried out from water extracts obtained from the dry caoutchouc films, so the same method can be used for examination of the rubber articles designed for the medicinetoo.

  7. Predicting transmission of shaped sonic booms into a residential house structure.

    Science.gov (United States)

    Sizov, Natalia V; Plotkin, Kenneth J; Hobbs, Christopher M

    2010-06-01

    Human perception of sonic booms is a major impediment to commercial supersonic flight. Shaping, which reduces the audible shock waves of a boom, can make outdoor perception of booms acceptable. Perception of sonic booms experienced indoors is of concern, and it is not yet established whether shaped booms offer benefit to indoor listeners. A better understanding of the transmission of shaped booms into building structures is needed. In the authors' earlier work the vibration response of house elements subjected to different sonic boom wave shapes was evaluated using a single degree of freedom model. This paper expands that approach with a modal analysis model. The acceleration of building elements and the resulting sound pressure inside a room are computed in the time and frequency domains. Analytical results are compared with experimental data measured by NASA during sonic boom tests conducted at Edwards Air Force Base in 2007. The effects of wave signature parameters on transmission are studied to evaluate the advantages of various kinds of minimized boom shapes.

  8. A dynamic model of mobile concrete pump boom based on discrete time transfer matrix method

    Science.gov (United States)

    Ren, Wu; Wu, Yunxin; Zhang, Zhaowei

    2013-12-01

    Mobile concrete pump boom is typical multibody large-scale motion manipulator. Due to posture constantly change in working process, kinematic rule and dynamic characteristic are difficult to solve. A dynamics model of a mobile concrete pump boom is established based on discrete time transfer matrix method (DTTMM). The boom system is divided into sub-structure A and substructure B. Sub-structure A is composed by the 1st boom and hydraulic actuator as well as the support. And substructure B is consists of the other three booms and corresponding hydraulic actuators. In the model, the booms and links are regarded as rigid elements and the hydraulic cylinders are equivalent to spring-damper. The booms are driven by the controllable hydraulic actuators. The overall dynamic equation and transfer matrix of the model can be assembled by sub-structures A and B. To get a precise result, step size and integration parameters are studied then. Next the tip displacement is calculated and compared with the result of ADAMS software. The displacement and rotation angle curves of the proposed method fit well with the ADAMS model. Besides it is convenient in modeling and saves time. So it is suitable for mobile concrete pump boom real-time monitoring and dynamic analysis. All of these provide reference to boom optimize and engineering application of such mechanisms.

  9. Reactions of Residents to Long-Term Sonic Boom Noise Environments

    Science.gov (United States)

    Fields, James M.

    1997-01-01

    A combined social survey and noise measurement program has been completed in 14 communities in two regions of the western United States that have been regularly exposed to sonic booms for many years. A total of 1,573 interviews were completed. Three aspects of the sonic booms are most disturbing: being startled, noticing rattles or vibrations, and being concerned about the possibility of damage from the booms. Sonic boom annoyance is greater than that in a conventional aircraft environment with the same continuous equivalent noise exposure. The reactions in the two study regions differ in severity.

  10. Establishment of new crops for the production of natural rubber.

    Science.gov (United States)

    van Beilen, Jan B; Poirier, Yves

    2007-11-01

    Natural rubber is a unique biopolymer of strategic importance that, in many of its most significant applications, cannot be replaced by synthetic alternatives. The rubber tree Hevea brasiliensis is the almost exclusive commercial source of natural rubber currently and alternative crops should be developed for several reasons, including: a disease risk to the rubber tree that could potentially decimate current production, a predicted shortage of natural rubber supply, increasing allergic reactions to rubber obtained from the Brazilian rubber tree and a general shift towards renewables. This review summarizes our knowledge of plants that can serve as alternative sources of natural rubber, of rubber biosynthesis and the scientific gaps that must be filled to bring the alternative crops into production.

  11. Microstructure and Properties of Desulfurized Crumb Rubber Modified Bitumen

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The microstructures of general crumb rubber(CR), dynamic desulfurized crumb rubber(DDCR) and high speed agitation desulfurized crumb rubber(HSADCR) modified bitumens were investigated by a fluorescence microscope, and the physical properties of these three modified bitumens were studied.The results show that the dynamic desulfuration can improve the swelling capacity of crumb rubber in bitumen by destroying the sulfuratized bond of the crumb rubber,but the reunion of rubber particles during dynamic desulfuration also makes the swelling and the DDCR in bitumen difficult, so properties of the DDCR modified bitumen are not superior to the general crumb rubber modified bitumen.However,high speed agitation desulfuration can not only improve the swelling capacity of crumb rubber in bitumen,but also avoid the reunion of rubber particles,so some properties of bitumen can be improved by the modification of HSADCR.

  12. Use of waste rubber as concrete additive.

    Science.gov (United States)

    Chou, Liang Hsing; Lu, Chun-Ku; Chang, Jen-Ray; Lee, Maw Tien

    2007-02-01

    For resource reutilization, scrap tyres have long been investigated as an additive to concrete to form 'Rubcrete' for various applications and have shown promising results. However, the addition of rubber particles leads to the degradation of physical properties, particularly, the compressive strength of the concrete. In this study, a theoretical model was proposed to shed light on the mechanisms of decrease in compressive strength due to the addition of rubber particles as well as improvement in compressive strength through modification of particle surfaces. The literature suggests that the compressive strength can be improved by soaking the rubber particles in alkaline solution first to increase the inter-phase bonding between the rubber particles and cement. Instead, we discovered that the loss in compressive strength was due to local imperfections in the hydration of cement, induced by the addition of heterogeneous and hydrophobic rubber particles. Microscopic studies showed that the rubber particles disturbed the water transfer to create channels, which were prone to cracking and led to a loss in the compressive strength. Unexpectedly, no cracking was found along the surfaces of the rubber particles, indicating that the bonding strength between the rubber particles and cement phases was not the critical factor in determining the compressive strength. Therefore, a theoretical model was proposed to describe the water transfer in the Rubcrete specimens to explain the experimental data. In the model, the local water available for hydration (Q) is: Q = -A(slv)/6piv, where Q, A(slv), and v are mass flow rate (kg s(-1)), Hamaker constant (J), and dynamic viscosity (m2 s(-1)), respectively. By maximizing the quantity Q and, in turn, the Hamaker constant A(slv), the compressive strength could be improved. The Hamaker constant A(slv) for water film on rubber particle surfaces was smaller than that for the hydrated cement particles; the water transfer rate was lower in

  13. Effect of non-rubber constituents on guayule and Hevea rubber intrinsic properties

    Science.gov (United States)

    To meet the increasing demand for natural rubber (NR), and address price volatility and steadily increasing labor costs, alternate rubber-producing species are in commercial development. One of these, guayule (Parthenium argentatum), has emerged on the market as a sustainable commercial source of h...

  14. Euphorbia characias latex: micromorphology of rubber particles and rubber transferase activity.

    Science.gov (United States)

    Spanò, Delia; Pintus, Francesca; Esposito, Francesca; Loche, Danilo; Floris, Giovanni; Medda, Rosaria

    2015-02-01

    We have recently characterized a natural rubber in the latex of Euphorbia characias. Following that study, we here investigated the rubber particles and rubber transferase in that Mediterranean shrub. Rubber particles, observed by scanning electron microscopy, are spherical in shape with diameter ranging from 0.02 to 1.2 μm. Washed rubber particles exhibit rubber transferase activity with a rate of radiolabeled [(14)C]IPP incorporation of 4.5 pmol min(-1)mg(-1). Denaturing electrophoresis profile of washed rubber particles reveals a single protein band of 37 kDa that is recognized in western blot analysis by antibodies raised against the synthetic peptide whose sequence, DVVIRTSGETRLSNF, is included in one of the five regions conserved among cis-prenyl chain elongation enzymes. The cDNA nucleotide sequence of E. characias rubber transferase (GenBank JX564541) and the deduced amino acid sequence appear to be highly homologous to the sequence of several plant cis-prenyltransferases.

  15. Boom in boarfish abundance: insight from otolith analysis

    DEFF Research Database (Denmark)

    Coad, Julie Olivia; Hüssy, Karin

    2012-01-01

    for this increase in stock size. Based on annual otolith growth increments, we developed a growth chronology as a proxy for stock fecundity. Growth patterns were similar between geographically separate areas west and south of Ireland, with distinct years of good and bad growth. Good growth was observed in 2004...... of fish are only aged 4–6 years. These age classes correspond to the year with exceptionally high recruitment. This study has demonstrated that both adult growth as a proxy for reproductive potential and environmental conditions favouring early life stage survival may be the cause for the boom in boarfish...

  16. Mass Boom Versus Big Bang Einstein was Right

    CERN Document Server

    Alfonso-Faus, A

    2003-01-01

    When considering possible time variations of fundamental physical constants one has to keep firm well established principles. Following this approach we keep firm the Action Principle, General Relativity (the Equivalence Principle), and Mach's Principle. Also we introduce a new principle under the name of "TOTAL INTERACTION" and reconsider Weinberg's relation with a new approach. Consistent with all these principles we find that all masses increase linearly with cosmological time (THE MASS BOOM) and that Planck's constant decreases also with this time.Then the whole quantum world shrinks with time too. This is the cause of the red shift

  17. Elastomers for Tracked Vehicles: 1980-1997 Program to Improve Durability of Rubber Tank Pads for Army Tracked Vehicles

    Science.gov (United States)

    2015-06-01

    blends of the polymers styrene butadiene rubber , natural rubber , and... Natural -SBR-PBD rubber blends : formulations .........................................................50 Table 15b Natural -SBR-PBD rubber blends ...properties .............................................................53 Table 16a SBR blends with natural and polybutadiene rubber

  18. 21 CFR 801.437 - User labeling for devices that contain natural rubber.

    Science.gov (United States)

    2010-04-01

    ... User labeling for devices that contain natural rubber. (a) Data in the Medical Device Reporting System..., natural rubber that contacts humans. The term “natural rubber” includes natural rubber latex, dry natural rubber, and synthetic latex or synthetic rubber that contains natural rubber in its......

  19. Micro-Ramps for External Compression Low-Boom Inlets

    Science.gov (United States)

    Rybalko, Michael; Loth, Eric; Chima, Rodrick V.; Hirt, Stefanie M.; DeBonis, James R.

    2010-01-01

    The application of vortex generators for flow control in an external compression, axisymmetric, low-boom concept inlet was investigated using RANS simulations with three-dimensional (3-D), structured, chimera (overset) grids and the WIND-US code. The low-boom inlet design is based on previous scale model 1- by 1-ft wind tunnel tests and features a zero-angle cowl and relaxed isentropic compression centerbody spike, resulting in defocused oblique shocks and a weak terminating normal shock. Validation of the methodology was first performed for micro-ramps in supersonic flow on a flat plate with and without oblique shocks. For the inlet configuration, simulations with several types of vortex generators were conducted for positions both upstream and downstream of the terminating normal shock. The performance parameters included incompressible axisymmetric shape factor, separation area, inlet pressure recovery, and massflow ratio. The design of experiments (DOE) methodology was used to select device size and location, analyze the resulting data, and determine the optimal choice of device geometry. The optimum upstream configuration was found to substantially reduce the post-shock separation area but did not significantly impact recovery at the aerodynamic interface plane (AIP). Downstream device placement allowed for fuller boundary layer velocity profiles and reduced distortion. This resulted in an improved pressure recovery and massflow ratio at the AIP compared to the baseline solid-wall configuration.

  20. Instability study of oil slicks contained by a single boom

    Energy Technology Data Exchange (ETDEWEB)

    Fang, J.; Wong, K.-F.V. [Miami Univ., Coral Gables, FL (United States). Dept. of Mechanical Engineering

    2000-07-01

    The different hydrodynamic instabilities that occur in the water-oil-boom systems were discussed. These instabilities are referred to as failures. The three major types of oil containment failures have been identified as being entrainment failure, drainage failure and critical accumulation failure. The primary factors which control instability are gravity, surface tension, current velocity, current depth, boom draft, oil viscosity and oil density. The impact that velocity has on the fluid flow at the water-oil interface was also discussed. This paper focused on a systematic study of the drainage failure and the critical accumulation failure. A numerical model was developed where two-dimensional flow was assumed. Two results were presented. One was characteristic of the interface movement, the other was the coefficient of collected oil and the critical containment conditions. Stability was found to be sensitive to the Froude number. It was also determined that the critical reduced gravity is more appropriate than the critical Froude number. 19 refs., 1 tab., 19 figs.

  1. Boom bomer boomste en die idiolek van Elsabe Steenberg

    Directory of Open Access Journals (Sweden)

    Elizabeth S. van der Westhuizen

    2014-06-01

    Full Text Available Boom bomer boomste and the idiolect of Elsabe Steenberg. Elsabe Steenberg’s oeuvre,consisting among others of 42 narratives in book format, is richly textured and represents a notable depth of insight into the complexities of life. It is clear that, from an intertextual point of view, considering the entire body of her work is a way of accumulating evidence in order to discern aspects of her distinctive idiolect. This idiolect, however, also emerges when contemplating a representative work from her oeuvre. The text selected for this article, a youth novel in which the symbolism of trees manifests itself in various semantic permutations,communicating the author’s intrinsic life and world view, is Boom bomer boomste, also available in English under the title Tree-more, tree-most. The tree as object and how it functions in the narrative to become part of the theme, as well as the vision of life in this youth novel, can be scrutinised minutely if the effort is aimed at finding frequent recurring signs that maybe regarded as representative of the author’s idiolect. The use of the tree symbolism in the narrative worlds of Elsabe Steenberg points toward the most prolific sign contributing to this author’s idiolect: God is the Origin and the regenerating Force in the universe of Elsabe Steenberg’s life and work.

  2. Suction effects in deep Boom clay block samples

    CERN Document Server

    Delage, Pierre; Tang, Anh-Minh; Cui, Yu-Jun; Li, Xiang-Ling

    2008-01-01

    Extensive investigations have been and are being carried out on a stiff clay from an underground research laboratory located at Mol (Belgium) called Boom clay, in the context of research into deep nuclear waste disposal. Suction effects in deep Boom clay block samples were investigated through the characterisation of the water retention and of the swelling properties of the clay. The data obtained allowed an estimation of the sample initial suction that was reasonably compatible with the in-situ state of stress at a depth of 223 m. The relationship between suction and stress changes during loading and unloading sequences were also examined by running oedometer tests with suction measurements. A rather wide range of the ratio s/sigma 'v (being s the suction and sigma 'v the effective vertical stress) was obtained (0.61 - 1), different from that proposed by Bishop et al; (1974). Finally, the effect of suction release under an isotropic stress close to the estimated sample suction was investigated. A slight swel...

  3. Passive diver detection and localization using hydrophones suspended under a boom

    NARCIS (Netherlands)

    Hunter, A.J.; Fillinger, L.; Clarijs, M.C.

    2013-01-01

    A boom is a line of floats that constitutes a physical barrier for providing abovewater stopping power. However, it does not provide any situation awareness. In order to overcome this shortcoming, an integrated “booms and sensors” solution using passive sonar was conceived and tested experimentally

  4. 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...

  5. Trends, Issues, Perspectives, and Values for the Aging of the Baby Boom Cohorts.

    Science.gov (United States)

    Cornman, John M.; Kingson, Eric R.

    1996-01-01

    Discusses the contours of population aging, especially the baby boom generation, and the political and economic changes in regard to the rapidly aging U.S. population. Focuses on entitlements such as social security and Medicare. Seeks to broaden national discourse on the aging of the baby boom cohorts through basic questions and clarification of…

  6. What Do We Know: The Impact of the Baby Boom Echo.

    Science.gov (United States)

    Mid-Atlantic Lab. for Student Success, Philadelphia, PA.

    The dramatic increase in the number of births after World War II, the "baby boom," lasted until the early 1960s. Another surge in births was recorded in 1977, the start of the baby boom echo. However, the number of births is not expected to decline again, with long-range projections indicating a rising number of births over the coming…

  7. Invited Commentary: The Baby Boom Echo Goes to College--by the Millions.

    Science.gov (United States)

    Riley, Richard W.

    2000-01-01

    The "Projections" report finds that the population surge of children of the baby boom ("baby boom echo") has moved into the high school and postsecondary education spheres. To be effective, education policies at all levels must reflect the changes in student enrollment predicted in the "Projections." Focuses on…

  8. America's Baby Boom Generation: The Fateful Bulge. Population Bulletin. Vol. 35, No. 1. April 1980.

    Science.gov (United States)

    Bouvier, Leon F.

    This bulletin examines the baby boom, its causes, its size, and its impact on U.S. society. Nearly 42 million births occurred in the U.S. from 1955 to 1964. Several reasons are given for this baby boom which interrupted a century long fertility decline. Demographically the primary causes were more people marrying and having at least two children…

  9. On America’s Baby Boom Generation and It’s Social Problems

    Institute of Scientific and Technical Information of China (English)

    杨娜

    2014-01-01

    Baby boom generation is the larger than expected generation in U.S born shortly after World War II. This post- World War II phenomenon upsets the phenomenon which had been a century-long decline in the U.S fertility rate. This paper simply analyzed America’s baby boom generation from three aspects.

  10. 76 FR 20532 - Safety Zone; Boom Days, Niagara River, Niagara Falls, NY

    Science.gov (United States)

    2011-04-13

    ..., 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, Niagara Falls, NY for the Boom... Niagara River, Niagara Falls, NY during the Boom Days Fireworks on April 16, 2011. This temporary...

  11. Rubber Tree (Hevea brasiliensis Muell. Arg).

    Science.gov (United States)

    Venkatachalam, Perumal; Jayashree, Radha; Rekha, Karumamkandathil; Sushmakumari, Sreedharannair; Sobha, Sankaren; Kumari Jayasree, Parukkuttyamma; Kala, Radha Gopikkuttanunithan; Thulaseedharan, Arjunan

    2006-01-01

    Rubber tree (Hevea brasiliensis Muell. Arg.) is an important industrial crop for natural rubber production. At present, more than 9.5 million hectares in about 40 countries are devoted to rubber tree cultivation with a production about 6.5 million tons of dry rubber each year. The world supply of natural rubber is barely keeping up with a global demand for 12 million tons of natural rubber in 2020. Tapping panel dryness (TPD) is a complex physiological syndrome widely found in rubber tree plantations, which causes severe yield and crop losses in natural rubber producing countries. Currently, there is no effective prevention or treatment for this serious malady. As it is a perennial tree crop, the integration of specific desired traits through conventional breeding is both time-consuming and labour-intensive. Genetic transformation with conventional breeding is certainly a more promising tool for incorporation of agronomically important genes that could improve existing Hevea genotype. This chapter provides an Agrobacterium-mediated transformation protocol for rubber tree using immature anther-derived calli as initial explants. We have applied this protocol to generate genetically engineered plants from a high yielding Indian clone RRII 105 of Hevea brasiliensis (Hb). Calli were co-cultured with Agrobacterium tumefaciens harboring a plasmid vector containing the Hb superoxide dismutase (SOD) gene and the reporter gene used was beta-glucuronidase (GUS) gene (uidA). The selectable marker gene used was neomycin phosphotransferase (nptII) and kanamycin was used as selection agent. We found that a suitable transformation protocol for Hevea consists of a 3-d co-cultivation with Agrobacterium in the presence of 20 mM acetosyringone, 15 mM betaine HCl, and 11.55 mM proline followed by selection on medium containing 300 mg/L kanamycin. Transformed calli surviving on medium containing 300 mg/L kanamycin showed a strong GUS-positive reaction. Upon subsequent subculture into

  12. Comparative analysis of rubber seed methyl ester with other methyl ...

    African Journals Online (AJOL)

    Comparative analysis of rubber seed methyl ester with other methyl esters. ... In order to achieve a two-step transesterification process was developed to convert rubber seed oil to its methyl esters. The first step, acid catalyzed ... Article Metrics.

  13. A crumb rubber modified syntactic foam

    Energy Technology Data Exchange (ETDEWEB)

    Li Guoqiang [Department of Mechanical Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Mechanical Engineering, Southern University, Baton Rouge, LA 70813 (United States)], E-mail: guoli@me.lsu.edu; John, Manu [Department of Mechanical Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States)

    2008-02-15

    In this study, the impact response and residual strength of a crumb rubber modified syntactic foam, which contained up to 20% by volume of crumb rubbers, were investigated. The foam had a hybrid microstructure bridging over several length scales. It was formed by dispersing hollow glass beads and crumb rubber particles into a microfiber and nanoclay filled epoxy matrix. Sandwich beam specimens were prepared using the hybrid foam as core and fiber reinforced epoxy as facings. A low velocity impact test using an instrumented drop tower impact machine was conducted on the sandwich beams and control beams made of the foam only. Four-point bending tests were conducted on the impact damaged specimens and control specimens without impact damage. The effect of the hybrid foam on the low velocity impact response and residual strength was evaluated based on the test results. The stress field interaction was evaluated using a finite element analysis. It was found that the rubberized syntactic foam possessed a higher capacity to dissipate impact energy and to retain bending strength. There was a positive composite action between the hollow glass bead particles and crumb rubber particles by means of stress field interaction and reduction in stress concentration.

  14. Removal Water Turbidity by Crumb Rubber Media

    Directory of Open Access Journals (Sweden)

    Abeer I. Alwared

    2014-06-01

    Full Text Available The removal of water turbidity by using crumb rubber filter was investigated .The present study was conducted to evaluate the effect of variation of influent water turbidity (10, 25 and 50 NTU, media size (0.6and 1.14mm, filtration rate (25, 45 and 65 l/hr and bed depth (30 and 60 cm on the performance of mono crumb rubber filter in response to the effluent filtered water turbidity and head loss development, and compare it with that of conventional sand filter. Results revealed that 25 l/hr flow rate and 25 NTU influent turbidity were the best operating conditions. smaller media size and higher bed depth gave the best removal efficiency while higher media size and small bed depth gave lower head loss. The optimum results show that 92.7% removal efficiency and 8.3 mm head loss. The comparison results show that at constant operating conditions, pressure drop for crumb rubber filter is lower than conventional sand filter; about 42% reduction in pressure drop than sand filter and the conventional sand filter has a little enhancement in removal efficiency than crumb rubber filter, 96.8% for sand while for crumb rubber 92.7%.

  15. 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.

  16. Dynamic response analysis of a moored crane-ship with a flexible boom

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The dynamic response of moored crane-ship is studied. Governing equations for the dynamic response of a crane-ship coupled with the pendulum motion of the payload are derived based on Lagrange's equations. The boom is modeled based on finite element method, while the payload is modeled as a planar pendulum of point mass. The dynamic response was studied using numerical method. The calculation results show that the large-amplitude responses occur at wave periods near the natural period of the payload. Load swing angle is smaller for crane-ship with flexible boom, in comparison with rigid boom. The ship surge motions have large vibrations for crane-ship with flexible boom, which were not observed for a rigid boom. The an alysis identifies the significance of key parameters and reveals how the system design can be adjusted to avoid critical conditions.

  17. Isolation of Microorganisms Able To Metabolize Purified Natural Rubber

    OpenAIRE

    Heisey, R. M.; Papadatos, S

    1995-01-01

    Bacteria able to grow on purified natural rubber in the absence of other organic carbon sources were isolated from soil. Ten isolates reduced the weight of vulcanized rubber from latex gloves by >10% in 6 weeks. Scanning electron microscopy clearly revealed the ability of the microorganisms to colonize, penetrate, and dramatically alter the physical structure of the rubber. The rubber-metabolizing bacteria were identified on the basis of fatty acid profiles and cell wall characteristics. Seve...

  18. Study on Production of Rubber Sealing Strips with Steel Bones

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Rubber sealing strips with steel bones are used in car manufacturing that produced in large quantities. Cutting processes, such as milling and punching, are needed when the strips are produced. Accuracy, smoothness and flatness of the machined surface have to be guaranteed in the cutting process; moreover, deformation of the steel bone and peeling-off of the rubber must be avoided. Therefore cutting action of rubber/steel strips differs from that of rubber or metal workpiece separately. In this paper, milli...

  19. 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.

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

    NARCIS (Netherlands)

    Poikelispaa, Minna; Das, Amit; Dierkes, Wilma; 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.

  1. Food Preferences of the Rubber Plantation Litter Beetle, Luprops tristis, a Nuisance Pest in Rubber Tree Plantations

    National Research Council Canada - National Science Library

    Thomas K. Sabu; K.V. Vinod

    2009-01-01

    .... Ready availability of the preferred, prematurely fallen, tender rubber tree leaves as a food resource is suggested as being responsible for the exceptionally high abundance of L. tristis in rubber tree plantation belts.

  2. 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 rubb

  3. Guayule and Russian dandelion as alternative sources of natural rubber.

    Science.gov (United States)

    van Beilen, Jan B; Poirier, Yves

    2007-01-01

    Natural rubber, obtained almost exclusively from the Para rubber tree (Hevea brasiliensis), is a unique biopolymer of strategic importance that, in many of its most significant applications, cannot be replaced by synthetic rubber alternatives. Several pressing motives lead to the search for alternative sources of natural rubber. These include increased evidence of allergenic reactions to Hevea rubber, the danger that the fungal pathogen Microcyclus ulei, causative agent of South American Leaf Blight (SALB), might spread to Southeast Asia, which would severely disrupt rubber production, potential shortages of supply due to increasing demand and changes in land use, and a general trend towards the replacement of petroleum-derived chemicals with renewables. Two plant species have received considerable attention as potential alternative sources of natural rubber: the Mexican shrub Guayule (Parthenium argentatum Gray) and the Russian dandelion (Taraxacum koksaghyz). This review will summarize the current production methods and applications of natural rubber (dry rubber and latex), the threats to the production of natural rubber from the rubber tree, and describe the current knowledge of the production of natural rubber from guayule and Russian dandelion.

  4. Interface interactions of natural rubber and protein/fiber aggregates

    Science.gov (United States)

    Mechanical properties of natural rubber are improved with a renewable filler for rubber applications. Aggregates of protein and fiber that constitute soy protein concentrate were shear-reduced and used to enhance the tensile modulus of the natural rubber. The aqueous dispersion of the shear-reduced ...

  5. 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

  6. 21 CFR 872.6300 - Rubber dam and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rubber dam and accessories. 872.6300 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6300 Rubber dam and accessories. (a) Identification. A rubber dam and accessories is a device composed of a thin sheet of latex with a hole in...

  7. 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....

  8. 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... be used and tested in accordance with the provisions of §§ 77.704-6 through 77.704-8. (b)...

  9. 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. ... waste minimization, utilization of waste, resource recovery and recycling of ... Key words: Rubber industry, effluent, waste management, Malaysia.

  10. Investigations on cementitious composites based on rubber particle waste additions

    Directory of Open Access Journals (Sweden)

    Glaucio Laun Nacif

    2013-04-01

    Full Text Available The amount of waste rubber has gradually increased over recent years because of over-growing use of rubber products. The disposal of waste rubber has caused serious environmental problems. The incorporation of recycled materials into cementitious composites is a feasible alternative that has gained ground in civil construction. The performance of such materials is much affected not only by the rubber addition, but also the particle size which has been controversially reported in the literature. In order to investigate the single effect of rubber particles into cement based materials, rubber cementitious composites were prepared with no silica particle additions. A full factorial design has been conducted to assess the influence of the rubber particle size (0.84/0.58 mm and 0.28/0.18 mm; mass fraction used (5, 15 and 30%; and water/cement ratio (0.35 and 0.50 on the physic-mechanical properties of the composites. The materials were characterized through apparent density, porosity, compressive strength, flexural strength, modulus of elasticity and microstructural analysis. The interactions of rubber particle size, rubber fraction and water/cement ratio affected significantly the density and compressive strength of the composites. The apparent porosity was influenced mainly by the rubber particle size. The flexural strength was affected by the main factors and the modulus of elasticity was affected by the interaction factors rubber particle size and fraction, and rubber fraction and w/c ratio.

  11. Development of rubber gloves by radiation vulcanization

    Science.gov (United States)

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

    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.

  12. The Properties of Sulfur Rubber Concrete (SRC)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mix designs and specimen preparation for the dry process and wet process of sulfur rubber concrete (SRC) were investigated.The compressive strength, corrosion-resistance and toughness were studied and discussed.The results show that SRC is corrosion-resistanct.Although the compressive strength of SRC decreases with increasing rubber content, the toughness increases instead.Adding micro-filler will improve the compressive strength of SRC. There is a threshold value for the sulfur content, at which the compressive strength and the work ability of SRC reach an optimum balanc e.The bond between rubber particles and surrounding sulfur is strong due to the vulcanization process that generates cross-links through S-C bonds.

  13. Supply of Rubber Wood Log in Malaysia

    Directory of Open Access Journals (Sweden)

    A. W. Noraida

    2014-06-01

    Full Text Available 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 was only harvested area having an impact with 1% significant level. This result indicates that, the harvested area become the most impact towards supply of rubber wood log either in short run or in the long run. While wages as input cost gave less impact in another word it become unburden to the producers.

  14. Effect of crumb rubber gradation on a rubberized cold recycled mixture for road pavements

    DEFF Research Database (Denmark)

    Pettinari, Matteo; Simone, Andrea

    2015-01-01

    asphalt design. The mix design represents a key phase of the cold mix production. The study of workability and compactability properties combined with a deep laboratory investigation is required. The idea of introducing crumb rubber in the cold mixtures was developed based on the concept of maximizing...... and cement. The spring-back effects of the rubber particles, which occur after compaction, together with the Indirect Tensile Strength and the Indirect Tensile Stiffness Modulus have been studied. The results show that the gradation of the adopted crumb rubber sensibly affects the compaction and mechanical...

  15. Oxygen exchange in silicone rubber capillaries.

    Science.gov (United States)

    Heineken, F G; Predecki, P K; Filley, G F

    1978-06-01

    Capillaries of 7 and 12.5 mu diameter have been fabricated in silicone rubber. Whole blood treated with heparin has been perfused through these capillaries. Under flowing conditions, no clotting or other clumping effects have been observed and red cells appear to maintain a constant velocity. Oxygen transfer data to and from saline perfusing the 12.5 mu diameter capillaries have been obtained in order to determine how rapidly O2 will permeate the silicone rubber film. The data indicate that the capillaries simulate lung tissue oxygen exchange and will allow for the first time the experimental determination of oxygen exchange kinetics in flowing whole blood.

  16. Clomipramina frente a fenelzina en el trastorno obsesivo-compulsivo

    OpenAIRE

    Vallejo Ruiloba, Julio; Olivares Gadea, Julia; Marcos, Teodor; Bulbena Vilarrasa, Antonio; Menchón Magriñá, José Manuel

    1994-01-01

    Un estudio clínico doble ciego con clomipramina frente a fenelzina fue llevado a cabo en 30 pacientes con trastorno obsesivo-compulsivo según el DSM-III. El período de estudio fue de 12 semanas, y las dosis máximas (a partir de la 5a semana) fueron 225 mg/día para clomipramina (14 pacientes) y 75 mg/día para fenelzina (12 pacientes); 4 pacientes abandonaron. Los síntomas obsesivos mejoraron significativamente en los dos grupos, pero no fiubo diferencia significativa entre ambos. Los síntomas ...

  17. La España del Frente Popular

    OpenAIRE

    Álvarez Chillida, Gonzalo; Alvarez Roblin, David; Bahamonde Magro, Ángel; Barraqué, Jean-Pierre; Béhar, Roland; Bernard, Gwladys; Branciforte, Laura; Brassous, Laurent; Ceamanos Llorens, Roberto; Coulon, Damien; Duarte Montserrat, Ángel; Ealham, Chris; Franco Mata, Ángela; García-Arenal, Mercedes; Godicheau, François

    2013-01-01

    El dossier aprovecha la conmemoración del 75º Aniversario del triunfo electoral del Frente Popular para hacer balance de algunos aspectos clave de una crisis social, política y de Estado tan decisiva para España como la de la primavera de 1936. Se aborda el uso y el abuso del concepto desde su acuñación como fórmula unitaria hasta su trasformación en arma retórica durante la guerra ; las manifestaciones de la violencia política en su vertiente cuantitativa y su tratamiento discursivo en el se...

  18. Rnas inhibidores frente al virus de la inmunodeficiencia humana

    OpenAIRE

    S??nchez Luque, Francisco Jos??

    2012-01-01

    En la presente tesis se describe la generaci??n de peque??as mol??culas de RNA con funci??n inhibidora frente al Virus de la Inmunodeficiencia Humana de Tipo 1 (VIH-1). Este virus es el agente causal del S??ndrome de Inmunodeficiencia Adquirida y perteneciente al g??nero Lentivirus de la familia Retroviridae. El virus presenta una alternancia en cuanto al tipo de material gen??tico en su ciclo de vida, siendo RNA en las part??culas virales y DNA en el provirus (durante la fase de latencia o e...

  19. A smart-hose for concrete displacing booms

    Science.gov (United States)

    Ripamonti, Francesco; Bucca, Giuseppe; Fava, Victor; Resta, Ferruccio

    2016-04-01

    During the last years, continuum robots have been used in many applications. They are smart structures with continuous curving, similar to a worm or an elephant trunk, characterized by a very high number of sub-actuated degrees of freedom (dof). They need a robust control system, aiming at both positioning the robot and suppressing induced vibrations. The idea is to adopt such a robot on a construction machine for the concrete distribution, substituting the reinforced rubber hose with the robotic smart solution. Particular attention has been paid to a control strategy able to reduce vibrations induced by the pumping procedure.

  20. Vibration measurement and modal analysis of boom type tunneller

    Energy Technology Data Exchange (ETDEWEB)

    Min, H.; Gong, L.; Miao, W.; Wei, A. [China University of Mining & Technology, Jiangsu (China)

    2003-04-01

    The vibrations of an AM50 boom tunnelling machine have been measured in real time when cutting a man-made and a real coal bed. The vibration characteristics were similar in these working conditions, i.e. the man-made coal bed can be used as a realistic simulation of real cutting conditions. A modal model of the machine was then established and the intrinsic vibration characteristics were investigated by experimental modal analysis. Vibration response simulations under a set of measured load spectra and structural dynamics modification were also carried out using structural analysis software. The results not only facilitate the structural dynamics modification of the AM50 tunneller but also provide a foundation for optimising the design of new types of tunnelling machine.

  1. Active control of shocks and sonic boom ground signal

    Science.gov (United States)

    Yagiz, Bedri

    The manipulation of a flow field to obtain a desired change is a much heightened subject. Active flow control has been the subject of the major research areas in fluid mechanics for the past two decades. It offers new solutions for mitigation of shock strength, sonic boom alleviation, drag minimization, reducing blade-vortex interaction noise in helicopters, stall control and the performance maximization of existing designs to meet the increasing requirements of the aircraft industries. Despite the wide variety of the potential applications of active flow control, the majority of studies have been performed at subsonic speeds. The active flow control cases were investigated in transonic speed in this study. Although the active flow control provides significant improvements, the sensibility of aerodynamic performance to design parameters makes it a nontrivial and expensive problem, so the designer has to optimize a number of different parameters. For the purpose of gaining understanding of the active flow control concepts, an automated optimization cycle process was generated. Also, the optimization cycle reduces cost and turnaround time. The mass flow coefficient, location, width and angle were chosen as design parameters to maximize the aerodynamic performance of an aircraft. As the main contribution of this study, a detailed parametric study and optimization process were presented. The second step is to appraise the practicability of weakening the shock wave and thereby reducing the wave drag in transonic flight regime using flow control devices such as two dimensional contour bump, individual jet actuator, and also the hybrid control which includes both control devices together, thereby gaining the desired improvements in aerodynamic performance of the air-vehicle. After this study, to improve the aerodynamic performance, the flow control and shape parameters are optimized separately, combined, and in a serial combination. The remarkable part of all these

  2. Tracking the Boom in Queensland’s Gasfields

    Directory of Open Access Journals (Sweden)

    Will Rifkin

    2014-09-01

    Full Text Available During rapid resource development in a highly contested arena, effective processes for characterising cumulative, social and economic impacts are needed. In this article, we explain a strategy that uses an iterative process involving stakeholders to identify indicators of impacts of onshore natural gas development. The aim of the strategy is to arrive at a small set of indicators that those in the community, government and industry agree are salient and credible.Four major joint ventures are investing more than A$60 billion to tap Queensland, Australia’s onshore natural gas resources. Thousands of wells are reaching into natural gas in seams of coal that lie below aquifers that residents refer to as essential for their heavily agricultural region. The magnitude of these developments has been depicted as threatening the traditional base of political power that has rested with farmers. Nearby coal mining has given some communities the experience of the boomtown cycle, but it is placing unfamiliar strains on municipal resources in other towns. Gas companies provide funds in attempts to mitigate impacts, satisfying requirements of their elaborate social impact management plans (SIMPs.The research reported in this paper, though only mid-way to completion, suggests that an action-research approach to developing indicators of cumulative impacts on housing, business, employment, liveability and trust in government shows promise for enabling stakeholders to track the multi-faceted effects of a resource boom.  We hope that such work helps stakeholders to mitigate the ups and downs of the cycle of boom, bust and recovery that can be driven by resource development.

  3. Simulation Process Analysis of Rubber Shock Absorber for Machine Tool

    Directory of Open Access Journals (Sweden)

    Chai Rong Xia

    2016-01-01

    Full Text Available The simulation on rubber shock absorber of machine tool was studied. The simple material model of rubber was obtained by through the finite element analysis software ABAQUS. The compression speed and the hardness of rubber material were considered to obtain the deformation law of rubber shock absorber. The location of fatigue were confirmed from the simulation results. The results shown that the fatigue position is distributed in the corner of shock absorber. The degree of deformation is increased with increasing of compress speed, and the hardness of rubber material is proportional to deformation.

  4. An interactive web-based design system for rubber injection mold: Automotive rubber parts

    Directory of Open Access Journals (Sweden)

    Chamnarn Thongmark

    2016-10-01

    Full Text Available This research aims at integrating a knowledge-based system and web-based technology to facilitate the rubber and rubber composite injection mold design. The system integrates both of computer-aided design and web-based management by using the application programming interface. The research processes started with gathering data and knowledge concerning on rubber injection mold design and process, with the designed framework of the system included. An example part was demonstrated in order to validate the developed system. Based on standardized procedures, the system provides counseling that is able to resolve relevant issues at the early stage of the mold design. The system can be used for both designing and training in rubber mold fabrication.

  5. Prediction of booming sensation and its difference limen for just noticeable change in frequency

    Science.gov (United States)

    Shin, Sung-Hwan; Ih, Jeong-Guon

    2003-10-01

    Among many auditory feelings for the car interior noise, the booming sensation is considered the most important nuisance to the passengers. Although there are many origins for the booming noise of vehicles in general, the most important one is the engine boom that consists of tonal components related to fundamental engine rotation and its harmonics including the firing frequency. Because the degree of booming sensation is increased when these tonal components are dominating in car interior noise, it is demanded to extract the aurally relevant tonal components only. Although the pitch extraction model based on the place theory enables to find aurally relevant tonal components, there is a difference between booming sensation and pitch perception according to a frequency change of the tonal component. In this study, a subjective listening test using a tracking method is performed to find the difference limen for just a noticeable change of booming sensation in frequency. By applying the resultant data and also the empirical data by Zwicker, the existing pitch extraction model is modified. This refined model and loudness analysis can be used for predicting the degree of booming sensation. [Work supported by the BK21 project and NRL.

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

    OpenAIRE

    A.B. Moustafa; Rania Mounir; A.A. El Miligy; Maysa A. Mohamed

    2016-01-01

    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 u...

  7. Behaviour of asphalt rubber mixtures with different crumb rubber and asphalt binder sources

    OpenAIRE

    Fontes, Liseane P. T. L.; Pereira, Paulo A. A.; Pais, Jorge C.; Trichês, Glicério

    2006-01-01

    This study evaluates the performance in laboratory of gap graded mixture prepared with different crumb rubber types and different conventional grade asphalt binders. The asphalt rubbers were prepared via wet process (continuous blend) and their properties were measured through the current tests: (i) penetration;(ii) softening point: (iii) resilience; (iv) apparent viscosity using a Brookfield viscometer. The rheological properties for conventional asphalts were measured too, in order to evalu...

  8. El impacto del TLC frente al derecho comunitario andino

    Directory of Open Access Journals (Sweden)

    Marcel Tangarife Torres

    2006-01-01

    Full Text Available En esta conferencia analiza el impacto del Tratado de Libre Comercio que se celebrará entre la República de Colombia y los Estados Unidos de Norteamérica frente al Derecho Comunitario Andino, con gran importancia en los temas relacionados con la propiedad intelectual. Adicional a lo anterior se suma un aspecto trascendental y es la supervivencia de la Comunidad Andina de Naciones y en este sentido se cuestiona la coexistencia de las normas comunitarias en relación con las previstas en el Tratado de Libre Comercio. De esta manera, se examina el marco constitucional del Tratado de Libre Comercio y del Acuerdo de Cartagena, para así determinar las características que tienen esta clase de tratados y con ello establecer el nivel jerárquico que le corresponden dentro del ordenamiento jurídico Colombiano. Finalmente se observa la prevalencía de las normas del Acuerdo de Cartagena y el Tratado de Libre Comercio o viceversa, para con ello encontrar soluciones frente a los posibles conflictos de normas que se pueden presentar por la coexistencia de dichas normatividades.

  9. El impacto del TLC frente al derecho comunitario andino

    Directory of Open Access Journals (Sweden)

    Marcel Tangarife Torres

    2006-11-01

    Full Text Available En esta conferencia analiza el impacto del Tratado de Libre Comercio que se celebrará entre la República de Colombia y los Estados Unidos de Norteamérica frente al Derecho Comunitario Andino, con gran importancia en los temas relacionados con la propiedad intelectual. Adicional a lo anterior se suma un aspecto trascendental y es la supervivencia de la Comunidad Andina de Naciones y en este sentido se cuestiona la coexistencia de las normas comunitarias en relación con las previstas en el Tratado de Libre Comercio. De esta manera, se examina el marco constitucional del Tratado de Libre Comercio y del Acuerdo de Cartagena, para así determinar las características que tienen esta clase de tratados y con ello establecer el nivel jerárquico que le corresponden dentro del ordenamiento jurídico Colombiano. Finalmente se observa la prevalencía de las normas del Acuerdo de Cartagena y el Tratado de Libre Comercio o viceversa, para con ello encontrar soluciones frente a los posibles conflictos de normas que se pueden presentar por la coexistencia de dichas normatividades.

  10. El médico frente a la muerte

    Directory of Open Access Journals (Sweden)

    Rosa Gómez Esteban

    2012-01-01

    Full Text Available Se plantean los cambios en relación a la muerte a lo largo de la historia. Se recoge el discurso más significativo del proceso de un grupo de médicos cos cuya tarea era trabajar sobre la relación médico-paciente, analizando los emergentes surgidos en relación a la problemática de la muerte. Se evidencian en los médicos mecanismos defensivos de negación muy intensos frente a la muerte de los pacientes, ma-yores cuanto más compleja es su propia vinculación con la muerte. Se trabajan estas ansiedades y meca-nismos defensivos en grupo operativo observando que es un instrumento de gran utilidad para la elaboración de estas dificultades de los médicos frente a la problemática de la muerte de los pacientes.

  11. 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.

  12. Rubber recovery from centrifuged natural rubber latex residue using sulfuric acid

    Directory of Open Access Journals (Sweden)

    Wirach Taweepreda

    2013-04-01

    Full Text Available Waste latex sludge from centrifuged residue, which is a null by-product of concentrated latex manufacturing, wasdigested to retrieve the rubber by using sulfuric acid. It was found that the acid concentration and digestion time have aneffect on the amount and purity of the retrieved rubber. Sulfuric acid at concentrations of more than 10% by weight with adigestion time of 48 hours completely digested waste latex sludge and gave rubber 10% by weight. The quality of the retrievedrubber was examined for Mooney viscosity (MV, plasticity retention index, nitrogen content, and ash content. The averagemolecular weight of the retrieved rubber, using gel permeation chromatography, was lower than that of normal natural rubber(NR which corresponds with the MV and initial plasticity (Po. The molecular structure from Fourier transform infraredspectroscopy (FT-IR indicated that the retrieved rubber surface is wet composed with hydroxyl functional ended group.The residue solution was evaporated and crystallized. The structure of crystals was determined using power X-ray diffractometer.

  13. Hardness and compression resistance of natural rubber and synthetic rubber mixtures

    Science.gov (United States)

    Arguello, J. M.; Santos, A.

    2016-02-01

    This project aims to mechanically characterize through compression resistance and shore hardness tests, the mixture of hevea brasiliensis natural rubber with butadiene synthetic rubber (BR), styrene-butadiene rubber (SBR) and ethylene-propylene-diene monomer rubber (EPDM). For each of the studied mixtures were performed 10 tests, each of which increased by 10% the content of synthetic rubber in the mixture; each test consisted of carrying out five tests of compression resistance and five tests of shore hardness. The specimens were vulcanized on a temperature of 160°C, during an approximate time of 15 minutes, and the equipment used in the performance of the mechanical tests were a Shimadzu universal machine and a digital durometer. The results show that the A shore hardness increases directly proportional, with a linear trend, with the content of synthetic BR, SBR or EPDM rubber present in the mixture, being the EPDM the most influential. With respect to the compression resistance is observed that the content of BR or SBR increase this property directly proportional through a linear trend; while the EPDM content also increases but with a polynomial trend.

  14. 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.

  15. Reinforcement of graphene in natural rubber nanocomposite

    Science.gov (United States)

    Azira, A. A.; Kamal, M. M.; Rusop, M.

    2016-07-01

    In the present work, we report the use of graphene as multi-functional nanofiller for natural rubber (NR). Dispersion of reduced graphene into natural rubber (NR) was found to enhance the mechanical and electrical properties of NR. Through a facile approach rubber molecules are successfully grafted onto the surface of graphene. Stable graphene suspension with NR afforded a weblike morphology consisting of platelet networks between the rubber particles, while internal mixer processing broke down this structure, yielding a homogeneous and improved dispersion. The resulting graphene can be dispersed in NR via dry mixing. It is found that graphene is prominent in improving the mechanical properties of NR at low filler loading. The percolation point of graphene in the nanocomposites takes place at a content of less than 0.1 wt%. With incorporation of as low as 0.1 wt% of graphene, an increase in the tensile strength and improvement in the tensile modulus achieved. The improvement in the mechanical properties of NR nanocomposites at such low filler loading is attributed to the strong interfacial interaction and the molecular-level dispersion of graphene in the NR matrix. .

  16. Valorisation of Proteins from Rubber Tree

    NARCIS (Netherlands)

    Widyarani,; Coulen, Stef C.W.; Sanders, Johan P.M.; Bruins, Marieke E.

    2016-01-01

    Purpose: The objective of this study was to identify the availability, possible applications, and economic potential of proteins that are present in different parts of the rubber tree. Proteins from non-food sources can be used in e.g. animal feed or biochemicals production with no or little competi

  17. Rubber Recycling: Chemistry, Processing, and Applications

    NARCIS (Netherlands)

    Myhre, M.; Saiwari, S.; Dierkes, W.K.; Noordermeer, J.W.M.

    2012-01-01

    For both environmental and economic reasons, there is broad interest in recycling rubber and in the continued development of recycling technologies. The use of postindustrial materials is a fairly well-established and documented business. Much effort over the past decade has been put into dealing wi

  18. NUTRITIVE VALUE OF RUBBER SEED (Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Md. Emran HOSSAIN

    2016-01-01

    Full Text Available The study was undertaken to find out the chemical composition of rubber seeds (Hevea brasiliensis available in Bangladesh. Hevea brasiliensis seeds were collected directly from 200 rubber trees of the rubber garden in the Bandarban area under standard random sampling technique. Seeds were decorticated, ground and dried in hot air oven. Chemical analyses of the samples were carried out in triplicate for moisture, dry matter (DM, crude protein (CP, crude fiber (CF, nitrogen free extract (NFE, ether extract (EE and ash in the animal nutrition laboratory, Chittagong Veterinary and Animal Sciences University, Chittagong, Bangladesh. Metabolizable energy (ME was calculated mathematically by using standard mathematical formula. Results indicated that, decorticated Hevea brasiliensis seeds contained 85.7% DM, 26.1% CP, 43.0% CF, 13.8% NFE, 11.0% EE and 1.8% ash. ME contents in in the seeds was 2101.1 kcal/kg DM. Since, decorticated rubber seeds contained substantial amount of metabolizable energy and proximate components, therefore it could be assumed that, like other unconventional feeds, it might be a promising feed resource for livestock.

  19. Numerical modelling of rubber vibration isolators

    NARCIS (Netherlands)

    Beijers, Clemens A.J.; Boer, de André; Nilsson, A.; Boden, H.

    2003-01-01

    An important cause for interior noise in vehicles is structure-borne sound from the engine. The vibrations of the source (engine) are transmitted to the receiver structure (the vehicle) causing interior noise in the vehicle. For this reason the engine is supported by rubber isolators for passive iso

  20. Rubber Impact on 3D Textile Composites

    Science.gov (United States)

    Heimbs, Sebastian; Van Den Broucke, Björn; Duplessis Kergomard, Yann; Dau, Frederic; Malherbe, Benoit

    2012-06-01

    A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools.

  1. Filled liquid silicone rubbers: Possibilities and challenges

    DEFF Research Database (Denmark)

    Yu, Liyun; Vudayagiri, Sindhu; Zakaria, Shamsul Bin

    2014-01-01

    Liquid silicone rubbers (LSRs) have been shown to possess very favorable properties as dielectric electroactive polymers due to their very high breakdown strengths (up to 170 V/μm) combined with their fast response, relatively high tear strength, acceptable Young’s modulus as well as they can...

  2. Identification and Waste Reduction on Rubber Industry

    Science.gov (United States)

    Syahputri, K.; Sari, R. M.; Rizkya, I.; Siregar, I.

    2017-03-01

    Lots of activities in production process can be lead to waste activities. The waste may cause a degree of efficiency of an industry to be low. This research was conducted in the rubber industry. In the rubber industry has been a decline in the level of efficiency. Decreased levels of efficiency occurs because many inefficient activities that take place during the production process. Activities that were not contributed to the value of the product lead to waste during the production process. Identification by the activity is a way to minimize the waste that occurs so that the efficiency of the production process can be improved. Process activity mapping in the rubber industry used to identify the activities that take place on the floor of production in order to reduce waste and propose improvements that can be done to improve efficiency. The total waste that occurs in crumb rubber industry amounted to 94 minutes or 1.56 hours. For the proposed improvements in order to reduce waste are based on two activities, such as transport and unnecessary motion. Transport activities proposed use of material handling in their daily activities and to unnecessary motion by doing a variety of work on the operator.

  3. Thermo-hydro-mechanical behaviour of Boom clay; Comportement thermo-hydro-mecanique de l'argile de Boom

    Energy Technology Data Exchange (ETDEWEB)

    Le, T.T

    2008-01-15

    This thesis studied the thermo-hydro-mechanical properties of Boom clay, which was chosen to be the host material for the radioactive waste disposal in Mol, Belgium. Firstly, the research was concentrated on the soil water retention properties and the hydro-mechanical coupling by carrying out axial compression tests with suction monitoring. The results obtained permitted elaborating a rational experimental procedure for triaxial tests. Secondly, the systems for high pressure triaxial test at controlled temperature were developed to carry out compression, heating, and shearing tests at different temperatures. The obtained results showed clear visco-elasto-plastic behaviour of the soil. This behaviour was modelled by extending the thermo-elasto-plastic model of Cui et al. (2000) to creep effect. (author)

  4. Remediation of floating, open water oil spills: Comparative efficacy of commercially available polypropylene sorbent booms

    Science.gov (United States)

    Schrader, Ed L.

    1991-03-01

    Several complex methods of remediation are applied to open water oil spills. Sorbing the liquid hydrocarbons with polypropylene booms is an effective and less complex means of treating such events. There are, however, a variety of commercially available booms which display different performances in sorbing different viscosity hydrocarbons. There is no acceptable A.S.T.M. protocol to evaluate these booms for performance efficiency in various weather and hydrocarbon viscosity scenarios. The current paper proposes such a protocol and evaluates the most commonly used sorbent products with the new test procedures. Nine specific performance criteria, based on actual field applications, are demonstrated.

  5. Cancer mortality and morbidity among rubber workers.

    Science.gov (United States)

    Monson, R R; Fine, L J

    1978-10-01

    Mortality and morbidity from cancer among a cohort of 13,570 white male rubber workers were examined. Each man worked for at least 5 years at the Akron, Ohio, plant of the B. F. Goodrich Company. The potential period of follow-up was from January 1, 1940 to June 30, 1976. Departmental work histories were based primarily on records maintained by Local no. 5, United Rubber Workers. The occurrence of cancer was measured by death certificates and by a survey of Akron-area hospital tumor registries from 1964 to 1974. Two types of analyses were made: 1) an external comparison of mortality rates of rubber workers versus rates of U.S. white males, and 2) an internal comparison of cancer morbidity rates among persons who were employed in various work areas of the plant. Excess cases of specific cancers (observed/expected numbers) among workers in specific work areas included: stomach and intestine: rubber making (30/14.4); lung: tire curing (31/14.1), fuel cells and/or deicers (46/29.1); bladder: chemical plant (6/2.4), and tire building (16/10.7); skin cancer: tire assembly (12/1.9); brain cancer: tire assembly (8/2.0); lymphatic cancer: tire building (8/3.2); and leukemia: calendering (8/2.2), tire curing (8/2.6), tire building (12/7.5), elevators (4/1.4), tubes (4/1.6), and rubber fabrics (4/1.1). Agents that may be responsible for these excesses were considered.

  6. 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.

  7. Sonic Boom Vibro-Acoustic Simulations using Multiple Point Sources Project

    Data.gov (United States)

    National Aeronautics and Space Administration — AVEC proposes an innovative concept for the evaluation of human response studies to sonic booms inside realistic structures. The approach proposed is to simulate the...

  8. A study of the limitations of linear theory methods as applied to sonic boom calculations

    Science.gov (United States)

    Darden, Christine M.

    1990-01-01

    Current sonic boom minimization theories have been reviewed to emphasize the capabilities and flexibilities of the methods. Flexibility is important because it is necessary for the designer to meet optimized area constraints while reducing the impact on vehicle aerodynamic performance. Preliminary comparisons of sonic booms predicted for two Mach 3 concepts illustrate the benefits of shaping. Finally, for very simple bodies of revolution, sonic boom predictions were made using two methods - a modified linear theory method and a nonlinear method - for signature shapes which were both farfield N-waves and midfield waves. Preliminary analysis on these simple bodies verified that current modified linear theory prediction methods become inadequate for predicting midfield signatures for Mach numbers above 3. The importance of impulse is sonic boom disturbance and the importance of three-dimensional effects which could not be simulated with the bodies of revolution will determine the validity of current modified linear theory methods in predicting midfield signatures at lower Mach numbers.

  9. An ElectroAdhesive "Stick Boom" for Mars Sample Return Orbiting Sample Capture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Electroadhesive "Sticky Boom", an innovative method for rendezvous and docking, is proposed for the Orbiting Sample Capture (OSC) portion of the Mars...

  10. Research on rigid–flexible coupling dynamic characteristics of boom system in concrete pump truck

    Directory of Open Access Journals (Sweden)

    Hongbin Tang

    2015-03-01

    Full Text Available Concrete pump truck plays an important role in infrastructure construction and national economic development. In recent years, its boom system becomes longer, and its dynamic and control become more complicated. In order to study the dynamic characteristics of boom system, three dynamic models such as multi-rigid-body model, rigid–flexible coupling model, and rigid–flexible coupling model with equivalent hydraulic cylinder were built in this work. Simulation analysis and experimental analysis were done, and they show that we should not only consider the large-range motion but also consider the small flexible deformation to study the dynamic characteristics of boom system precisely. It provides the theoretical basis to vibration control, trajectory prediction, and life assessment for boom system and such structures.

  11. Development of Multiobjective Optimization Techniques for Sonic Boom Minimization

    Science.gov (United States)

    Chattopadhyay, Aditi; Rajadas, John Narayan; Pagaldipti, Naryanan S.

    1996-01-01

    improve the aerodynamic, the sonic boom and the structural characteristics of the aircraft. The flow solution is obtained using a comprehensive parabolized Navier Stokes solver. Sonic boom analysis is performed using an extrapolation procedure. The aircraft wing load carrying member is modeled as either an isotropic or a composite box beam. The isotropic box beam is analyzed using thin wall theory. The composite box beam is analyzed using a finite element procedure. The developed optimization procedures yield significant improvements in all the performance criteria and provide interesting design trade-offs. The semi-analytical sensitivity analysis techniques offer significant computational savings and allow the use of comprehensive analysis procedures within design optimization studies.

  12. Numerical modelling and experimentation of oil-spill curtain booms: Application to a harbor

    Science.gov (United States)

    Muttin, F.; Campbell, R.; Ouansafi, A.; Benelmostafa, Y.

    2017-01-01

    Oil-spill curtain booms are an important response device dedicated to containing and deviating floating pollutants. The hydrodynamic and structural limitations of curtain booms necessitate numerical modelling for efficient usage assessment. A four step model is proposed and applied during an exercise performed in the Galician region of Spain. Experimental results are used to produce a re-analysis of the model and improve contingency planning.

  13. Living standards, terms of trade and foreign ownership: reflections on the Australian mining boom

    OpenAIRE

    2012-01-01

    Australia is experiencing its largest mining boom for more than a century and a half. This paper explores, from a national perspective, important economic differences that arise when a mining boom, such as the current one, is generated by sustained export price increases (trading gains) rather than export volume increases. Since 2003, the terms of trade changes – through their direct trading gain effect and indirect real GDP effects – have increased Australian living standards. The increase, ...

  14. Booming far: the long-range vocal strategy of a lekking bird.

    Science.gov (United States)

    Cornec, C; Hingrat, Y; Aubin, T; Rybak, F

    2017-08-01

    The pressures of selection acting on transmission of information by acoustic signals are particularly high in long-distance communication networks. Males of the North African houbara bustard (Chlamydotis undulata undulata) produce extremely low-frequency vocalizations called 'booms' as a component of their courtship displays. These displays are performed on sites separated by a distance of on average 550 m, constituting exploded leks. Here, we investigate the acoustic features of booms involved in species-specific identity. We first assessed the modifications of acoustic parameters during boom transmission at long range within the natural habitat of the species, finding that the frequency content of booms was reliably transmitted up to 600 m. Additionally, by testing males' behavioural responses to playbacks of modified signals, we found that the presence of the second harmonic and the frequency modulation are the key parameters for species identification, and also that a sequence of booms elicited stronger responses than a single boom. Thus, the coding-decoding process relies on redundant and propagation-resistant features, making the booms particularly well adapted for the long-range transmission of information between males. Moreover, by experimentally disentangling the presentation of visual and acoustic signals, we showed that during the booming phase of courtship, the two sensory modalities act in synergy. The acoustic component is dominant in the context of intra-sexual competition. While the visual component is not necessary to induce agonistic response, it acts as an amplifier and reduces the time of detection of the signaller. The utilization of these adaptive strategies allows houbara males to maximize the active space of vocalizations emitted in exploded leks.

  15. Prediction of Fatigue Life of Boom Nose End Casting Using Linear Elastic Fracture Mechanics

    OpenAIRE

    Nitin D.Ghongade; Rajesh.M. Metkar

    2014-01-01

    The main objective of this study is to get the life estimation of Boom nose end casting using theoretical approach and compaired it with finite element method. Therefore, this study consists of three major sections : (1) dynamic load analysis (2) FEM and stress analysis (3) prediction of fatigue life for Boom nose end casting. In this study a dynamic loads were obtained from cyclic loading at different time. Finite element analysis was performed to obtain the variation of stress...

  16. Effects of Aircraft Noise and Sonic Booms on Domestic Animals and Wildlife: A Literature Synthesis

    Science.gov (United States)

    1988-06-01

    Aquatic mammals: Beluga whale Boat traffic (Acoustical Easily displaced Society of America 1980) Pinnepeds Sonic booms (80-89 dBA SPL) Startle...Arctic mammals are limited. Beluga whales (Delphinapterus leucas) are more easily displaced by boat traffic when feeding, and bowhead whales (Balaena...population of ravens (Corvus corax) to a sonic boom in central Wales Three or four ravens were idling in the upcurrents over a high rock spur between

  17. El médico frente a la muerte

    OpenAIRE

    2012-01-01

    Se plantean los cambios en relación a la muerte a lo largo de la historia. Se recoge el discurso más significativo del proceso de un grupo de médicos cos cuya tarea era trabajar sobre la relación médico-paciente, analizando los emergentes surgidos en relación a la problemática de la muerte. Se evidencian en los médicos mecanismos defensivos de negación muy intensos frente a la muerte de los pacientes, ma-yores cuanto más compleja es su propia vinculación con la muerte. Se trabajan estas ansie...

  18. La responsabilidad de los medios frente a los usuarios

    Directory of Open Access Journals (Sweden)

    Germán Suárez Castillo

    2005-01-01

    Full Text Available El autor analiza la reciente experiencia dejada por las sentencias judiciales dictadas en las acciones populares interpuestas contra cuatro programas radiales en Colombia, que demostró que el consumidor y el usuario anónimo están en capacidad de exigir un mínimo de condiciones frente a la programación que diariamente reciben del medio de comunicación. Las decisiones adoptadas por las corporaciones judiciales contra el sistema radial plantean a los demás medios de comunicación la necesidad de revisar, por cuenta propia, las políticas aplicadas a sus relaciones con los consumidores y usuarios, especialmente sobre la calidad de sus productos.

  19. El Frente Nacional: una historia de enemistad social

    Directory of Open Access Journals (Sweden)

    Mauricio Archila Neira

    2010-07-01

    Full Text Available El régimen de coalición bipartidista que gobernó a Colombia entre 1958 y 1974 tuvo el mérito de atenuar la confrontación por colores políticos pero ahondó la brecha social que produjo nuevas enemistades en el país. El contraste entre las anteriores apreciaciones de personajes claves en la historia contemporánea nacional así lo indica. A lo largo del Frente Nacional diversos actores sociales también fueron percibiendo dicha transformación y sacando sus propias conclusiones para la acción concreta. Algunos de ellos en forma muy temprana.

  20. 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.

  1. An Analysis of Measured Pressure Signatures From Two Theory-Validation Low-Boom Models

    Science.gov (United States)

    Mack, Robert J.

    2003-01-01

    Two wing/fuselage/nacelle/fin concepts were designed to check the validity and the applicability of sonic-boom minimization theory, sonic-boom analysis methods, and low-boom design methodology in use at the end of the 1980is. Models of these concepts were built, and the pressure signatures they generated were measured in the wind-tunnel. The results of these measurements lead to three conclusions: (1) the existing methods could adequately predict sonic-boom characteristics of wing/fuselage/fin(s) configurations if the equivalent area distributions of each component were smooth and continuous; (2) these methods needed revision so the engine-nacelle volume and the nacelle-wing interference lift disturbances could be accurately predicted; and (3) current nacelle-configuration integration methods had to be updated. With these changes in place, the existing sonic-boom analysis and minimization methods could be effectively applied to supersonic-cruise concepts for acceptable/tolerable sonic-boom overpressures during cruise.

  2. SCAMP: Rapid Focused Sonic Boom Waypoint Flight Planning Methods, Execution, and Results

    Science.gov (United States)

    Haering, Edward A., Jr.; Cliatt, Larry J., II; Delaney, Michael M., Jr.; Plotkin, Kenneth J.; Maglieri, Domenic J.; Brown, Jacob C.

    2012-01-01

    Successful execution of the flight phase of the Superboom Caustic Analysis and Measurement Project (SCAMP) required accurate placement of focused sonic booms on an array of prepositioned ground sensors. While the array was spread over a 10,000-ft-long area, this is a relatively small region when considering the speed of a supersonic aircraft and sonic boom ray path variability due to shifting atmospheric conditions and aircraft trajectories. Another requirement of the project was to determine the proper position for a microphone-equipped motorized glider to intercept the sonic boom caustic, adding critical timing to the constraints. Variability in several inputs to these calculations caused some shifts of the focus away from the optimal location. Reports of the sonic booms heard by persons positioned amongst the array were used to shift the focus closer to the optimal location for subsequent passes. This paper describes the methods and computations used to place the focused sonic boom on the SCAMP array and gives recommendations for their accurate placement by future quiet supersonic aircraft. For the SCAMP flights, 67% of the foci were placed on the ground array with measured positions within a few thousand feet of computed positions. Among those foci with large caustic elevation angles, 96% of foci were placed on the array, and measured positions were within a few hundred feet of computed positions. The motorized glider captured sonic booms on 59% of the passes when the instrumentation was operating properly.

  3. Modeling and Analysis of Truck Mounted Concrete Pump Boom by Virtual Prototyping

    Directory of Open Access Journals (Sweden)

    Wu Ren

    2017-01-01

    Full Text Available By far there is lack of research on different working conditions between rigid and flexible dynamics of truck mounted concrete pump booms. First a 3D model has been established by using virtual prototyping technology of a 37 m long boom in Pro/Engineering software. Then the rigid body simulation model has been built. Next modal superimposition method is adopted to change the 4 rigid body booms into flexible ones. Kinematics law and dynamic characteristics of 4 common working conditions had been studied then. Next tip displacement and the first boom hydraulic cylinder force of the 4 working conditions between rigid and flexible models have been researched. Furthermore the first natural frequencies of the structure have been calculated. The results show that the frequency of the horizontal condition has the lowest of all and the roof condition has the largest of all. Besides the cylinder forces of the flexible model are larger than the corresponding rigid ones because of the flexible boom vibration. Finally an experiment has been done on a boom test rig which proved that the established simulation model is reasonable and the frequency results are correct. All of these provide design reference to mechanical manipulator as well as reducing product development cost of such mechanism.

  4. Morphogenic Regulators Baby boom and Wuschel Improve Monocot Transformation.

    Science.gov (United States)

    Lowe, Keith; Wu, Emily; Wang, Ning; Hoerster, George; Hastings, Craig; Cho, Myeong-Je; Scelonge, Chris; Lenderts, Brian; Chamberlin, Mark; Cushatt, Josh; Wang, Lijuan; Ryan, Larisa; Khan, Tanveer; Chow-Yiu, Julia; Hua, Wei; Yu, Maryanne; Banh, Jenny; Bao, Zhongmeng; Brink, Kent; Igo, Elizabeth; Rudrappa, Bhojaraja; Shamseer, P M; Bruce, Wes; Newman, Lisa; Shen, Bo; Zheng, Peizhong; Bidney, Dennis; Falco, S Carl; RegisterIII, James C; Zhao, Zuo-Yu; Xu, Deping; Jones, Todd J; Gordon-Kamm, William James

    2016-09-06

    While transformation of the major monocot crops is currently possible, the process typically remains confined to one or two genotypes per species, often with poor agronomics, and efficiencies that place these methods beyond the reach of most academic laboratories. Here, we report a transformation approach involving overexpression of the maize (Zea mays) Baby boom (Bbm) and maize Wuschel2 (Wus2) genes, which produced high transformation frequencies in numerous previously non-transformable maize inbred lines. For example, the Pioneer inbred PHH5G is recalcitrant to biolistic and Agrobacterium transformation. However, when Bbm and Wus2 were expressed, transgenic calli were recovered from over 40% of the starting explants, with most producing healthy, fertile plants. Another limitation for many monocots is the intensive labor and greenhouse space required to supply immature embryos for transformation. This problem could be alleviated by using alternative target tissues that could be supplied consistently with automated preparation. As a major step toward this objective, we transformed Bbm and Wus2 directly into either embryo slices from mature seed or leaf segments from seedlings in a variety of Pioneer inbred lines, routinely recovering healthy, fertile T0 plants. Finally, we demonstrated that the maize Bbm and Wus2 genes stimulate transformation in sorghum (Sorghum bicolor) immature embryos, sugarcane (Saccharum officinarum) callus, and indica rice (Oryza sativa var. indica) callus. {copyright, serif} 2016 American Society of Plant Biologists. All rights reserved.

  5. Boom, Bust and Beyond: Arts and Sustainability in Calumet, Michigan

    Directory of Open Access Journals (Sweden)

    Richelle Winkler

    2016-03-01

    Full Text Available Cycles of boom and bust plague mining communities around the globe, and decades after the bust the skeletons of shrunken cities remain. This article evaluates strategies for how former mining communities cope and strive for sustainability in the decades well beyond the bust, using a case study of Calumet, Michigan. In 1910, Calumet was at the center of the mining industry in the Upper Peninsula of Michigan, but in the century since its peak, mining employment steadily declined until the last mine closed in 1968, and the population declined by over 80%. This paper explores challenges, opportunities, and progress toward sustainability associated with arts-related development in this context. Methods are mixed, including observation, interviews, document review, a survey, and secondary data analysis. We follow Flora and Flora’s Community Capitals Framework to analyze progress toward sustainability. Despite key challenges associated with the shrunken city context (degraded tax base, overbuilt and aging infrastructure, diminished human capital, and a rather limited set of volunteers and political actors, we find the shrunken city also offers advantages for arts development, including low rents, less risk of gentrification, access to space, and political incentive. In Calumet, we see evidence of a spiraling up pattern toward social sustainability resulting from arts development; however impacts on environmental and economic sustainability are limited.

  6. Pultrusion Process Development for Long Space Boom Model

    Science.gov (United States)

    Wilson, Maywood L.; Miserentino, Robert

    1988-01-01

    Long flexible-boom models were required to develop ground-vibration test methods for very-low-frequency space structures with applications to the proposed Space Station. Pultruded quasi-isotropic composite beams were selected as an option over extruded aluminum alloy structures because of the lower cost potential, the higher specific strength, the flexural properties, and the dynamic similarity considerations. The reinforcement material that was used was biaxial (0 deg/90 deg) fiberglass roving held in place with knitted polyester yarn such that equal fiber volume in 0 deg and 90 deg orientations provided nearly equal strength in both longitudinal and transverse directions. An isophthalic polyester resin system was used as the matrix. Continuous lengths up to 270 ft were easily pultruded with biaxial fabric. Tracking problems were encountered with similar unidirectional fabrics. Analyses of processing problems were conducted to determine causes for delamination, scaling, and sloughing. Ultrasonic C-scanning and scanning electron microscope examinations were conducted as well as mechanical testing to failure. Test results indicate that pultrusion processes can be used to produce quasi-isotropic composite structures.

  7. A sonic boom propagation model including mean flow atmospheric effects

    Science.gov (United States)

    Salamone, Joe; Sparrow, Victor W.

    2012-09-01

    This paper presents a time domain formulation of nonlinear lossy propagation in onedimension that also includes the effects of non-collinear mean flow in the acoustic medium. The model equation utilized is an augmented Burgers equation that includes the effects of nonlinearity, geometric spreading, atmospheric stratification, and also absorption and dispersion due to thermoviscous and molecular relaxation effects. All elements of the propagation are implemented in the time domain and the effects of non-collinear mean flow are accounted for in each term of the model equation. Previous authors have presented methods limited to showing the effects of wind on ray tracing and/or using an effective speed of sound in their model equation. The present work includes the effects of mean flow for all terms included in the augmented Burgers equation with all of the calculations performed in the time-domain. The capability to include the effects of mean flow in the acoustic medium allows one to make predictions more representative of real-world atmospheric conditions. Examples are presented for nonlinear propagation of N-waves and shaped sonic booms. [Work supported by Gulfstream Aerospace Corporation.

  8. Shape memory rubber bands & supramolecular ionic copolymers

    Science.gov (United States)

    Brostowitz, Nicole

    The primary focus of this dissertation is to understand the thermo-mechanical properties that govern shape memory in rubber blends. An ideal shape memory polymer (SMP) has a large entropic component that drives shape recovery with a distinct transition mechanism to control the recovery conditions. Polyisoprene rubber is highly elastic and shows shape memory behavior through strain induced crystallization above its glass transition temperature. However, this transition temperature is below 0°C and not suitable for most applications. Shape memory blends can tailor the transition temperature through selection of the switching phase. Most SMP blends require complicated synthesis routes or intensive compounding which would be inhibitive for production. A facile method was developed for fabrication of a robust shape memory polymer by swelling cross-linked natural rubber with stearic acid. Thermal, microscopic studies showed that stearic acid formed a percolated network of crystalline platelets within the natural rubber. Further investigation of the material interactions was carried out with a low molecular weight polyisoprene analog, squalene, and stearic acid gel. Tensile tests on the rubber band demonstrated the thermo-mechanical effect of swelling with stearic acid. Low hysteresis was observed under cyclic loading which indicated viability for the stearic acid swollen rubber band as an SMP. The microscopic crystals and the cross-linked rubber produce a temporary network and a permanent network, respectively. These two networks allow thermal shape memory cycling with deformation and recovery above the melting point of stearic acidand fixation below that point. Under manual, strain-controlled tensile deformation, the shape memory rubber bands exhibited fixity and recovery of 100% +/- 10%. The recovery properties of the SMP were studied under various loading conditions and a model was fit to describe the potential recovery with relation to the fixation. An additional

  9. Occupational disease in the rubber industry.

    Science.gov (United States)

    Peters, J M; Monson, R R; Burgess, W A; Fine, L J

    1976-10-01

    We have studied mortality patterns in a large cohort of rubber workers. We have examined workers exposed to curing fumes, processing dusts, and industrial talc and have begun to evaluate exposures of these workers in detail. Gastrointestinal (especially stomach) cancer appears in excess in processing workers. Lung cancer is excessive in curing workers. Leukemia is increased generally. All three groups studied for respiratory disease have an increase in disease prevalence which is related to intensity and duration of exposure. Since both an increase in stomach cancer and respiratory disease is seen in processing workers, exposures in this area must be controlled. Since both lung cancer and chronic respiratory disease is excessive in curing rooms, this exposure must be controlled. The leukemia risk is probably related to solvents. Whether this is all explainable by past benzene exposure is unknown. Further studies are planned to refine our knowledge concerning these risks so that occupational disease in the rubber industry can be prevented.

  10. Synthetic rubbers prepared by lanthanide coordination catalysts

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China is rich in rare earth resources. Rare earth elements, also named lanthanides, are number 58 to number 81 elements in the elemental periodic table. They have unique electronic structures and may form various coordination compounds. In the early 1960s, researchers at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (CIAC) found the catalytic activities of lanthanide compounds in stereospecific polymerization of conjugated dienes, and published the first paper on this topic in 1964. On the basis of this finding, CIAC launched extensive research activities on lanthanide compounds as diene polymerization catalysts, from a series of fundamental research to the efforts of industrializing the rare earth catalyzed cis-1,4-polybutatine rubber and cis-1,4-polyisoprene rubber. This review aims to summarize the progress in this field in the past half century.

  11. Synthetic rubbers prepared by lanthanide coordination catalysts

    Institute of Scientific and Technical Information of China (English)

    CHEN WenQi; WANG FoSong

    2009-01-01

    China is rich in rare earth resources. Rare earth elements, also named Ianthanides, are number 58 to number 81 elements in the elemental periodic table. They have unique electronic structures and may form various coordination compounds. In the early 1960s, researchers at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (CIAC) found the catalytic activities of lanthanide compounds in stereospecific polymerization of conjugated dienes, and published the first paper on this topic in 1964. On the basis of this finding, CIAC launched extensive research activities on lanthanide compounds as diene polymerization catalysts, from a series of fundamental research to the efforts of industrializing the rare earth catalyzed cis~(-1),4-polybutatine rubber and cis~(-1),4-polyisoprene rubber. This review aims to summarize the progress in this field in the past half century.

  12. 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.

  13. Biodiesel Production from Rubber Seed Oil via Esterification Process

    Directory of Open Access Journals (Sweden)

    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%.

  14. MODIFYING V-14 RUBBER WITH CARBON FIBERS

    Directory of Open Access Journals (Sweden)

    Shadrinov N. V.

    2016-01-01

    Full Text Available The influence of carbon fibers and modified carbon fibers on properties of industrially produced V-14 rubber is examined. The dependences of physical and mechanical properties, hardness, abrasion resistance and resistance in aggressive environment on few amount of filled fiber are established. Structural properties of reinforced elastomeric composites are studied by scanning electron microscopy. Elastomeric layer on the surface of modified carbon fiber, confirmed with high adhesion is identified

  15. Magnesium affects rubber biosynthesis and particle stability in Ficus elastica, Hevea brasiliensis and Parthenium argentatum

    Science.gov (United States)

    Natural rubber biosynthesis occurs in laticifers of Ficus elastica and Hevea brasiliensis, and in parenchyma cells of Parthenium argentatum. Natural rubber is synthesized by rubber transferase using allylic pyrophosphates as initiators, isopentenyl pyrophosphate as monomeric substrate and magnesium ...

  16. 75 FR 36472 - Goodyear Tire and Rubber Company, Receipt of Petition for Decision of Inconsequential Noncompliance

    Science.gov (United States)

    2010-06-25

    ... National Highway Traffic Safety Administration Goodyear Tire and Rubber Company, Receipt of Petition for Decision of Inconsequential Noncompliance Goodyear Tire and Rubber Company, (Goodyear),\\1\\ has determined... 573, Defect and Noncompliance Responsibility and Reports. \\1\\ Goodyear Tire and Rubber...

  17. 78 FR 9775 - Cooper Tire & Rubber Company, Receipt of Petition for Decision of Inconsequential Noncompliance

    Science.gov (United States)

    2013-02-11

    ... National Highway Traffic Safety Administration Cooper Tire & Rubber Company, Receipt of Petition for.... ACTION: Receipt of Petition. SUMMARY: Cooper Tire & Rubber Company (Cooper),\\1\\ has determined that..., Defect and Noncompliance Responsibility and Reports. \\1\\ Cooper Tire & Rubber Company, is a...

  18. 76 FR 28502 - Cooper Tire & Rubber Tire Company, Receipt of Petition for Decision of Inconsequential Noncompliance

    Science.gov (United States)

    2011-05-17

    ... National Highway Traffic Safety Administration Cooper Tire & Rubber Tire Company, Receipt of Petition for Decision of Inconsequential Noncompliance Cooper Tire & Rubber Tire Company, (Cooper),\\1\\ has determined...\\ Cooper Tire & Rubber Tire Company (Cooper) is a replacement equipment manufacturer incorporated in...

  19. 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 .

  20. Use of rubber crumb for preparation of asphalt-concrete mixtures

    OpenAIRE

    Yerbol Tileuberdi; S. Kozbakarova; Yerdos Ongarbayev; B. Tuleutaev; Zulkhair Mansurov

    2012-01-01

    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 .

  1. Tensile Strength of PHBV/Natural Rubber Latex Mixtures

    OpenAIRE

    Promkotra Sarunya; Kangsadan Tawiwan

    2015-01-01

    A polyhydroxybutyrate-co-hydroxyvalerate (PHBV) is mingled with natural rubber latex (R) to develop its mechanical property of the blend. Normally, substantial effects of the PHBV are hard, fragile, and inelastic, whereas the natural rubber is represented itself as very high elastic matter. The mixtures between the PHBV and natural rubber latex (R) are considered in different proportions. The PHBV solutions (w/v) are defined suitability at 1% (P1), 2% (P2), and 3% (P3). Their liquid mixtures ...

  2. Impact resistance of concrete – using slit rubber from tyres

    OpenAIRE

    Coventry, Kathryn; Richardson, Alan; Diaz, Eli

    2015-01-01

    This paper examines recycled tyre rubber, which was machine cut into slits and these were added to Portland cement concrete mixes in different percentages, based on specimen volume. They were then tested to determine the impact performance of each mix in comparison to a plain non-rubberised mix. \\ud The results indicated that concrete samples containing recycled rubber, exhibited a loss in compressive strength when compared to the plain concrete mix, however, the rubber modified samples were ...

  3. The improvement of pavement performance using asphalt rubber hot mixes

    OpenAIRE

    Pais, Jorge C.; Pereira, Paulo A. A.

    2007-01-01

    The need of a better pavement performance has led researchers to develop new road materials, mainly for the asphalt layers, where the modification of the asphalt is the main example. This modification usually forces the use of polymers and fibers and, more recently, the use of crumb rubber from ground tires, where the modified asphalt is known as asphalt rubber. This asphalt rubber used in asphalt mixtures produces a superior performance if compared to the asphalt mixtures with...

  4. Effect of base bitumen composition on asphalt rubber binder properties

    OpenAIRE

    Partl, M.N.; Ould-Henia, M.; Dumont, A.-G.

    2008-01-01

    The asphalt rubber blend properties are strongly related to its base components properties. The base bitumen composition is considered as a key factor influencing the final rheological properties of asphalt rubber binder. This paper describes results from a laboratory investigation of the interaction between crumb rubber and different composition bitumen according to the wet process. The bitumen composition is determined according to the SARA decomposition approac...

  5. Design, manufacturing and testing of Controllable Rubber Trailing Edge Flaps

    DEFF Research Database (Denmark)

    Løgstrup Andersen, Tom; Aagaard Madsen, Helge; Barlas, Thanasis K

    The overall goal for the INDUFLAP project was realization of a test facility for development and test of Controllable Rubber Trailing Edge Flaps (CRTEF) for wind turbines. This report covers experimental work at DTU Wind Energy including design, manufacture and test of different configurations...... of flaps with voids in chord- or spanwise direction. Development of rubber flaps has involved further design improvements. Non-metallic spring elements and solutions for sealing of continuous extruded rubber profiles have been investigated....

  6. Impact resistance of concrete – using slit rubber from tyres

    OpenAIRE

    Coventry, Kathryn; Richardson, Alan; Diaz, Eli

    2015-01-01

    This paper examines recycled tyre rubber, which was machine cut into slits and these were added to Portland cement concrete mixes in different percentages, based on specimen volume. They were then tested to determine the impact performance of each mix in comparison to a plain non-rubberised mix. \\ud The results indicated that concrete samples containing recycled rubber, exhibited a loss in compressive strength when compared to the plain concrete mix, however, the rubber modified samples were ...

  7. Mortality among rubber workers: V. processing workers.

    Science.gov (United States)

    Delzell, E; Monson, R R

    1982-07-01

    Cause-specific mortality was evaluated among 2,666 men employed in the processing division of a rubber manufacturing plant. The division was divided into two sections: front processing (compounding, mixing and milling operations) and back processing (extrusion, calendering, cement mixing and rubberized fabrics operations). Mortality rates for all processing workers combined and for men in each section were compared with rates for U.S. White males or for workers employed in other divisions of the same plant. Compared with either referent group, men in the processing division had increased mortality from leukemia, emphysema, and cancers of the stomach, large intestine, and biliary passages and liver. An excess number of deaths from stomach and larger intestine cancer was found predominantly among men in the front processing section (33 observed vs. 17.7 expected deaths, based on rates in nonprocessing workers). Increased mortality from leukemia (14 observed vs. 7.3 expected) and from emphysema (22 observed vs. 11.0 expected) was present among men employed in the back processing section. Examination of mortality from these causes according to age and the year starting work, duration of employment, and years since starting work in the relevant sections of the processing division suggested that observed excesses of stomach cancer, large intestine cancer, leukemia, and emphysema among processing workers are related to occupational exposures. These results are consistent with the findings of studies of other groups of rubber workers.

  8. Boron-Loaded Silicone Rubber Scintillators

    CERN Document Server

    Bell, Z W; Maya, L; Sloop, F V J

    2003-01-01

    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 respons...

  9. Elucidation of filler-to-filler and filler-to-rubber interactions in silica-reinforced natural rubber by TEM Network Visualization

    NARCIS (Netherlands)

    Sarkawi, S.S.; Dierkes, W.K.; Noordermeer, J.W.M.

    2014-01-01

    Filler-to-rubber interaction is a key parameter in the reinforcement of rubber. This paper presents an investigation into filler-to-filler and filler-to-rubber interactions in silica-reinforced natural rubber (NR) in the presence and absence of a silane coupling agent. Using a special network visual

  10. Barrierity of hydrogenated butadiene-acrylonitrile rubber and butyl rubber after exposure to organic solvents.

    Science.gov (United States)

    Krzemińska, Sylwia; Rzymski, Władysław M

    2011-01-01

    Resistance of antichemical clothing primarily depends on the type of material it is made from, in particular on the type of polymer used for coating the fabric carrier. This paper reports on systematic investigations on the influence of the cross-linking density of an elastomer and the composition of a cross-linked elastomer on its resistance to permeation of selected organic solvents. Tests of barrier material samples made from nonpolar butyl rubber (IIR) and polar hydrogenated butadiene-acrylonitrile rubber (HNBR) showed that (a) in rubber-solvent systems with medium thermodynamic affinity, cross-linking density influenced resistance to permeation and (b) the polarity of the system had a significant influence on barrierity.

  11. 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.

  12. [Contamination of solid-cast rubber tires by microscopic fungi].

    Science.gov (United States)

    Chuienko, A I; Subbota, A H; Olishevs'ka, S V; Zaslavs'kyĭ, V A; Zhdanova, N M

    2010-01-01

    The main peculiarities of fungal resistance of two types of unit cast rubber tires of domestic manufacture have been investigated. Rubber tires which contained synthetic plasticizer were non-resistant to fungal contamination in contrast to ones with natural plasticizer. Using the method of confocal laser-scanning microscopy, it was shown that inner layers of two types of rubber tires were contaminated with fungal mycelium. Our findings indicate that the investigation of microscopic fungi resistance of new materials is necessary for general mechanical rubber goods, especially exported to tropical climate countries.

  13. 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

  14. Research on the sound absorption performance of metal rubber material

    Institute of Scientific and Technical Information of China (English)

    XIA Yuhong; JIANG Hongyuan; WU Guoqi; E.A. Izzheurov

    2009-01-01

    The sound absorption performance of Metal Rubber material was studied theoreti-cally and experimentally. The acoustic impedance rate and the sound absorption coefficient were derived based on the acoustic parameters of metal rubber material. The relation of structure constant, compressibility modulus and structural parameters was investigated experimentally. The results showed that the specimen of metal rubber with the same mean porosity diame-ter had the same structure constant. For the same structural parameters, the compressibility modulus of metal rubber material was approximately constant in certain frequency range. The calculated acoustic parameters are in good agreement with the experimental results, demon-strating the effectiveness of theoretical models.

  15. Effect of Chipped Rubber Aggregates on Performance of Concrete

    Directory of Open Access Journals (Sweden)

    Sunil N. Shah

    2014-12-01

    Full Text Available Due to rapid growth in automobile industry, use of tyre increases day to day and there is no reuse of the same to decrease the environmental pollution. The decomposition and disposing of waste tyre rubber is harmful to environment. This research reflects the reuse of waste tyre rubber into concrete after observing their properties. In that experimental work chipped rubber aggregates replaced to the natural coarse aggregates by varying percentage of 3, 6, 9 and 12 with comparison of 0% replacement. Silica fume is replaced in 10% with cement for improving the bond properties between cement paste and rubber. In evaluation, test has been carried out to determine the properties of concrete such as workability, unit weight, flexural strength and split tensile strength. The workability of fresh concrete is observed with the help of compaction factor test. From the test of compaction factor, workability is decrease with increasing percentage of chipped rubber. The specific gravity of chipped rubber aggregates is lower as compared to natural aggregates therefore decrease the unit weight of rubber mix concrete. Increasing chipped rubber aggregates as partial replacement into concrete reduces compressive strength. So these can use in non-primary structural applications of medium to low strength requirements. The overall results of study show that it is possible to use recycled rubber tyre aggregates in concrete construction as partial replacement to natural coarse aggregates.

  16. Comparative thermal analysis of the Space Station Freedom photovoltaic deployable boom structure using TRASYS, NEVADA, and SINDA programs

    Science.gov (United States)

    Baumeister, Joseph F.; Beach, Duane E.; Armand, Sasan C.

    1989-01-01

    The proposed Space Station Photovoltaic Deployable Boom was analyzed for operating temperatures. The boom glass/epoxy structure design needs protective shielding from environmental degradation. The protective shielding optical properties (solar absorptivity and emissivity) dictate the operating temperatures of the boom components. The Space Station Boom protective shielding must also withstand the effects of the extendible/retractable coiling acting within the mast canister. A thermal analysis method was developed for the Space Station Deployable Boom to predict transient temperatures for a variety of surface properties. The modeling procedures used to evaluate temperatures within the boom structure incorporated the TRASYS, NEVADA, and SINDA thermal analysis programs. Use of these programs led to a comparison between TRASYS and NEVADA analysis methods. Comparing TRASYS and NEVADA results exposed differences in the environmental solar flux predictions.

  17. 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.

  18. Influence of temperature changes on torsional rigidity and damping coefficient of rubber torsional vibration damper

    OpenAIRE

    Wojciech HOMIK

    2011-01-01

    The short explanation of usefulness of rubber torsional dampers in crankshaft in multi-cylinder engines is presented. The description of the construction and operation of rubber torsional damper is also included. In the rubber torsional damper, the damping is achieved as the effect of internal friction resulting from the deformation of the rubber material. This deformation appears while the internal rubber elasticity is overloaded. Both the physical and mechanical rubber properties depend on ...

  19. Advanced Deployable Shell-Based Composite Booms for Small Satellite Structural Applications Including Solar Sails

    Science.gov (United States)

    Fernandez, Juan M.

    2017-01-01

    State of the art deployable structures are mainly being designed for medium to large size satellites. The lack of reliable deployable structural systems for low cost, small volume, rideshare-class spacecraft severely constrains the potential for using small satellite platforms for affordable deep space science and exploration precursor missions that could be realized with solar sails. There is thus a need for reliable, lightweight, high packaging efficiency deployable booms that can serve as the supporting structure for a wide range of small satellite systems including solar sails for propulsion. The National Air and Space Administration (NASA) is currently investing in the development of a new class of advanced deployable shell-based composite booms to support future deep space small satellite missions using solar sails. The concepts are being designed to: meet the unique requirements of small satellites, maximize ground testability, permit the use of low-cost manufacturing processes that will benefit scalability, be scalable for use as elements of hierarchical structures (e.g. trusses), allow long duration storage, have high deployment reliability, and have controlled deployment behavior and predictable deployed dynamics. This paper will present the various rollable boom concepts that are being developed for 5-20 m class size deployable structures that include solar sails with the so-called High Strain Composites (HSC) materials. The deployable composite booms to be presented are being developed to expand the portfolio of available rollable booms for small satellites and maximize their length for a given packaged volume. Given that solar sails are a great example of volume and mass optimization, the booms were designed to comply with nominal solar sail system requirements for 6U CubeSats, which are a good compromise between those of smaller form factors (1U, 2U and 3U CubeSats) and larger ones (12 U and 27 U future CubeSats, and ESPA-class microsatellites). Solar

  20. Design of Experiments for Both Experimental and Analytical Study of Exhaust Plume Effects on Sonic Boom

    Science.gov (United States)

    Castner, Raymond S.

    2009-01-01

    Computational fluid dynamics (CFD) analysis has been performed to study the plume effects on sonic boom signature for isolated nozzle configurations. The objectives of these analyses were to provide comparison to past work using modern CFD analysis tools, to investigate the differences of high aspect ratio nozzles to circular (axisymmetric) nozzles, and to report the effects of under expanded nozzle operation on boom signature. CFD analysis was used to address the plume effects on sonic boom signature from a baseline exhaust nozzle. Nearfield pressure signatures were collected for nozzle pressure ratios (NPRs) between 6 and 10. A computer code was used to extrapolate these signatures to a ground-observed sonic boom N-wave. Trends show that there is a reduction in sonic boom N-wave signature as NPR is increased from 6 to 10. As low boom designs are developed and improved, there will be a need for understanding the interaction between the aircraft boat tail shocks and the exhaust nozzle plume. These CFD analyses will provide a baseline study for future analysis efforts. For further study, a design of experiments has been conducted to develop a hybrid method where both CFD and small scale wind tunnel testing will validate the observed trends. The CFD and testing will be used to screen a number of factors which are important to low boom propulsion integration, including boat tail angle, nozzle geometry, and the effect of spacing and stagger on nozzle pairs. To design the wind tunnel experiment, CFD was instrumental in developing a model which would provide adequate space to observe the nozzle and boat tail shock structure without interference from the wind tunnel walls.

  1. Inverse Design of Low-Boom Supersonic Concepts Using Reversed Equivalent-Area Targets

    Science.gov (United States)

    Li, Wu; Rallabhand, Sriam

    2011-01-01

    A promising path for developing a low-boom configuration is a multifidelity approach that (1) starts from a low-fidelity low-boom design, (2) refines the low-fidelity design with computational fluid dynamics (CFD) equivalent-area (Ae) analysis, and (3) improves the design with sonic-boom analysis by using CFD off-body pressure distributions. The focus of this paper is on the third step of this approach, in which the design is improved with sonic-boom analysis through the use of CFD calculations. A new inverse design process for off-body pressure tailoring is formulated and demonstrated with a low-boom supersonic configuration that was developed by using the mixed-fidelity design method with CFD Ae analysis. The new inverse design process uses the reverse propagation of the pressure distribution (dp/p) from a mid-field location to a near-field location, converts the near-field dp/p into an equivalent-area distribution, generates a low-boom target for the reversed equivalent area (Ae,r) of the configuration, and modifies the configuration to minimize the differences between the configuration s Ae,r and the low-boom target. The new inverse design process is used to modify a supersonic demonstrator concept for a cruise Mach number of 1.6 and a cruise weight of 30,000 lb. The modified configuration has a fully shaped ground signature that has a perceived loudness (PLdB) value of 78.5, while the original configuration has a partially shaped aft signature with a PLdB of 82.3.

  2. A Review on the Effect of Crumb Rubber Addition to the Rheology of Crumb Rubber Modified Bitumen

    Directory of Open Access Journals (Sweden)

    Mohd Rasdan Ibrahim

    2013-01-01

    Full Text Available Crumb rubber modification has been proven to enhance the properties of pure bitumen. This paper looks at some of the international standards for producing crumb rubber modified bitumen (CRMB and reviews the effect of crumb rubber to the rheology of crumb rubber modified bitumen. The review shows that the rheology of CRMB depends on internal factors such as crumb rubber quantity, particle size, and pure bitumen composition, and external factors such as the mixing time, temperature, and also the modification technique. These factors govern the swelling process of crumb rubber particles that lead to the increase of viscosity of the modified bitumen. However, the mixing temperature and duration can cause rubber particles to depolymerize and subsequently cause loss of viscosity. Crumb rubber modification also improves the properties of bitumen by increasing the storage and loss modulus and enhancing the high and low temperature susceptibility. The effect of crumb rubber to aging properties of CRMB is also discussed. Finally several techniques of chemical modification to terminal blends of CRMB and the subsequent improvement to the settling property of CRMB are explained.

  3. Health care in Costa Rica: boom and crisis.

    Science.gov (United States)

    Mesa-Lago, C

    1985-01-01

    In 1960-1980 Costa Rica experienced a health boom, achieving significant improvements which moved that country into the number two position in Latin America for indicators such as population coverage, infant mortality, life expectancy and health services. In addition, there was a gradual process of integration of health services. But in the same period, the cost of health care as a percentage of GNP increased almost 5-fold and in 1980 was the fourth highest in the region. The economic crisis of the 1980s aggravated the financial difficulties; to cope with them, the government introduced an austere program to reduce costs and plans to transform the current model of health care into a more efficient one capable of maintaining Costa Rica's high health standards in the future. The paper is divided into five sections: summary of the historical development of health care, and description of its current organization and of its gradual process of integration; estimation of population coverage and its trends, evaluation of inequalities in coverage, and identification of the non-covered group; analysis of health-care financing and its sources, as well of the recent financial desequilibrium, its causes and measures to restore the equilibrium; description of health care benefits and their differences among groups and regions, analysis of the country's advances in health-care facilities and standards, and measurement of the impact of the health care system in income distribution; and description of the rising cost of health care and the current crisis, analysis of the causes of both phenomena, and review of the measures that have been and should be implemented to solve these problems.

  4. Frentes de brisa en el Levante español

    Directory of Open Access Journals (Sweden)

    Olcina Cantos, Jorge

    2004-03-01

    Full Text Available Breeze regimes are main winds circulation during warm period of the year (April-September in the East of the Iberian Peninsula. This analysis offers a typology of sea breeze fronts in Spanish Mediterranean area and considers its close relationship with thermal features in Mediterranean sea all year along. The paper studies meteorological causes connected with this atmospheric phenomenon and emphasizes about pluviometric importance in contact with origin of instable sea breeze fronts in mountain areas near to Mediterranean coast.

    [es] Los regímenes de brisas constituyen la principal circulación de vientos durante el semestre cálido del año (abril-septiembre en el Levante español. El presente estudio establece una tipología de frentes de brisa que se desarrollan en este espacio geográfico ibérico y su estrecha relación con los rasgos térmicos del mar Mediterráneo a lo largo del año. Se analizan las causas atmosféricas asociadas a este fenómeno meteorológico y se enfatiza en la importancia pluviométrica ligada al estallido de frentes de brisa inestables en las áreas montañosas próximas al litoral mediterráneo. [fr] Les circulations de brises constitue le mécanisme principal de vents pendant le semestre chaud de l'année (avril - septembre sur le Levant Espagnol. L'étude présente établit une typologie de fronts de brise qui développent dans cet espace géographique et son la relation étroite avec les caractéristiques thermales de la mer Méditerranée pendant l'année. Là sont analysé les raisons atmosphériques associées à ce phénomène météorologique et il est souligné dans l'importance pluviométrica lié à la formation de fronts instables de brise dans les secteurs montagneux près le littoral méditerranée espagnol.

  5. Inmunidad frente a infecciones: bacterias, virus, hongos y parásitos

    OpenAIRE

    Sen Fernández, María Luz de la; Sempere Ortells, José Miguel; Marco de la Calle, Francisco Manuel; Vázquez Araujo, Begoña

    2012-01-01

    Respuesta inmune frente a la infección: Bacterias extracelulares, bacterias intracelulares, hongos, virus, parásitos. Inmunidad innata, inmunidad adaptativa, mecanismos de evasión, consecuencias perjudiciales de la respuesta inmune.

  6. New application of crystalline cellulose in rubber composites

    Science.gov (United States)

    Bai, Wen

    Rubber without reinforcement has limited applications. The strength of reinforced rubber composites can be ten times stronger than that of unreinforced rubbers. Therefore, rubber composites are widely used in various applications ranging from automobile tires to seals, valves, and gaskets because of their excellent mechanical elastic properties. Silica and carbon black are the two most commonly used reinforcing materials in rubber tires. They are derived from non-renewable materials and are expensive. Silica also contributes to a large amount of ash when used tires are disposed of by incineration. There is a need for a new reinforcing filler that is inexpensive, renewable and easily disposable. Cellulose is the most abundant natural polymer. Native cellulose includes crystalline regions and amorphous regions. Crystalline cellulose can be obtained by removing the amorphous regions with the acid hydrolysis of cellulose because the amorphous cellulose can be hydrolyzed faster than crystalline cellulose. We recently discovered that the partial replacement of silica with microcrystalline cellulose (MCC) provided numerous benefits: (1) low energy consumption for compounding, (2) good processability, (3) strong tensile properties, (4) good heat resistance, and (5) potential for good fuel efficiency in the application of rubber tires. Strong bonding between fillers and a rubber matrix is essential for imparting rubber composites with the desired properties for many specific applications. The bonding between hydrophilic MCC and the hydrophobic rubber matrix is weak and can be improved by addition of a coupling agent or surface modifications of MCC. In this study, MCC was surface-modified with acryloyl chloride or alkenyl ketene dimer (AnKD) to form acrylated MCC (A-MCC) and AnKD-modified MCC (AnKD-MCC). The surface modifications of MCC did not change the integrity and mechanical properties of MCC, but provided functional groups that were able to form covalent linkages with

  7. Sonic booms produced by US Air Force and US Navy aircraft: Measured data

    Science.gov (United States)

    Lee, R. A.; Downing, J. M.

    1991-01-01

    A sonic measurement program was conducted at Edwards Air Force Base. Sonic boom signatures, produced by F-4, F-14, F-15, F-16, F-18, F-111, SR-71, and T-38 aircraft, were obtained under the flight track and at various lateral sites which were located up to 18 miles off-track. Thirteen monitors developed by Det 1 AL/BBE were used to collect full sonic boom waveforms, and nine modified dosimeters were used to collect supplemental peak overpressures and the C-weighted Sound Exposure Levels (CSEL) for 43 near steady supersonic flights of the above United States Air Force and United States Navy aircraft. This report describes the measured database (BOOMFILE) that contains sonic boom signatures and overpressures, aircraft tracking, and local weather data. These measured data highlight the major influences on sonic boom propagation and generation. The data from this study show that a constant offset of 26 from the peak overpressure expressed in dB gives a good estimate of the CSEL of a sonic boom.

  8. Innovative Escapement-Based Mechanism for Micro-Antenna Boom Deployment

    Science.gov (United States)

    Tokarz, Marta; Grygorczuk, Jerzy; Jarzynka, Stanislaw; Gut, Henryk

    2014-01-01

    This paper presents the prototype of a tubular boom antenna developed for the Polish BRITE-PL satellite by the Space Research Center of the Polish Academy of Sciences (CBK PAN). What is unique about our work is that we developed an original type of the tubular boom antenna deployment mechanism that can be used widely as a basic solution for compact electrical antennas, booms deploying sensitive instruments, ultra-light planetary manipulators etc. The invented electromagnetic driving unit provides a dual complementary action - it adds extra energy to the driving spring, making the system more reliable, and at the same time it moderates the deployment speed acting as a kind of damper. That distinguishing feature predetermines the mechanism to be applied wherever the dynamic nature of a spring drive introducing dangerous vibrations and inducing severe local stress in the structure needs to be mitigated. Moreover, the paper reveals a product unique in Europe - a miniature beryllium bronze tubular boom free of geometry and strain defects, which is essential for stiffness and fatigue resistance. Both the deployment mechanism and the technology of tubular boom manufacturing are protected by patent rights.

  9. TRABAJADORES ARGENTINOS: respuestas y propuestas frente a la ofensiva neoliberal

    Directory of Open Access Journals (Sweden)

    Santiago Duhalde

    Full Text Available El objetivo de este artículo es examinar algunas experiencias de trabajadores argentinos que no cedieron frente al avance del neoliberalismo en los años 1990, sino que, al contrario, se organizaron y lograron resistir y en algunos casos contrarrestar la ofensiva política de aquella década. Nos referimos a tres experiencias clave para entender este proceso histórico. En primer lugar, la organización y acción de los trabajadores desocupados, hecho que rompe con cualquier lógica explicativa de la sociología clásica; en segundo lugar, la construcción de un sindicalismo alternativo por parte de los empleados del Estado, en un contexto de fuerte embestida contra este último; y, finalmente, el proceso de organización político de un grupo de trabajadores del transporte, que fue y sigue siendo testimonio insoslayable para todos aquellos obreros que deseen organizarse y luchar en un contexto de repliegue sindical. En definitiva, este artículo muestra las construcciones políticas de las que son capaces los trabajadores aun en momentos de pérdida o ausencia de referencias identitarias e institucionales.

  10. Hydrogeology of Pico Frentes Karst system (Iberian range, Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Rosas, P.; Sanz, E.; Menendez-Pidal, I.

    2016-07-01

    The karst system of Pico Frentes has developed within an Upper Cretaceous calcareous series whose welldefined folded geometry determines that its aquifer reserves are held mainly in three hydraulically-connected synclines, with a groundwater capacity of between 5 and 7 hm3 . The recharge to this unconfined peneplain aquifer is autogenous and diffuse. On a large scale, groundwater flow is directed by the base of the synclines, while on a small scale, it flows along groundwater conduits towards the Fuentetoba Spring (210 l/s) and source of the River Mazos (50 l/s), following a highly variable flow regime of low inertia, with other smaller discharges emanating during periods of high water. Analysis of hydrographs of these springs indicates a very variable rate system and little power regulating natural, characteristic of a typical karstic aquifer, with great capacity for renewal and low residence time. Using hydrogram simulations of these upwellings using a mathematical rainfall-runoff model, a detailed quantification of the average water balance was made for a twenty-year time series. This water balance consists of 16,86 hm3 rainfall (100%); natural recharge, 8,35 hm3 (49,53%); EVT 8,50 hm3 (50,41%); pumped groundwater abstractions, 0,01hm3 (0,06%); surface runoff, 0 hm3, groundwater transfers to other aquifer, 0 hm3. (Author)

  11. Experimental study of temperature distribution in rubber material during microwave heating and vulcanization process

    Science.gov (United States)

    Chen, Hai-Long; Li, Tao; Liang, Yun; Sun, Bin; Li, Qing-Ling

    2017-03-01

    Microwave technology has been employed to heat sheet rubber, the optical fiber temperature online monitor and optical fiber temperature sensor have been employed to measure the temperature in sheet rubber. The temperature of sheet rubber increased with increase of heating time during microwave heating process in which the maximum of temperature was rubber was higher than the rate of temperature rising in marginal zone of sheet rubber, and the final temperature in central zone of sheet rubber was also higher than the final temperature in marginal zone of sheet rubber. In the microwave heating and vulcanization process of sheet rubber, the maximum of rate of temperature rising and the maximum of temperature belong to the central zone of sheet rubber, so the distribution of electric field was uneven in heating chamber, which led to the uneven temperature distribution of sheet rubber. The higher electric field intensity value converges on the central zone of sheet rubber.

  12. 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.

  13. Penelitian penggunaan campuran karet alam RSS dengan stiren butadien rubber (SBR dalam pembuatan soft rubber lining

    Directory of Open Access Journals (Sweden)

    Penny Setyowati

    1995-06-01

    Full Text Available The objective of this research is to obtain optimum composition of RSS and SBR compound for making soft rubber lining compound. Based on seven combination of trials in compound formulation proved that formulation with composition of RSS 50 parts and SBR 50 parts give the best physical properties and highly cemented on steel by using “Desmodur R” adhesive solution.

  14. Creep Characteristics of Crumb Rubber Modified Asphalt Binder

    Institute of Scientific and Technical Information of China (English)

    WANG Lan; CHANG Chunqing; XING Yongming

    2011-01-01

    Crumb rubber modified asphalt containing 20 percent crumb rubber particles of 30mesh has been examined by Scanning Electron Microscope (SEM) to observe the microcosmic appearance and the characteristic distribution of crumb rubber particles in asphalt. The SEM pictures reveal that the crumb rubber particles distribute evenly in the asphalt and they are compatible well with asphalt. The shear creep test of crumb rubber modified asphalt was carried out at - 10 ℃ and 40 ℃ by Dynamic Shear Rheology (DSR). The shearing deformation at different temperature and creep stiffness modulus curve at loading stage of crumb rubber modified asphalt have been measured. The stiffness modulus of crumb rubber modified asphalt is much temperature sensitive and it decays much quick at the early stage of loading than normal asphalt. The rate of decay of stiffness modulus is slow at the subsequent stage and stiffness modulus approaches to a stable value at the final stage at a higher temperature. In addition, Burgers model is suitable to describe and simulate experimental results of viscoelastic properties of the crumb rubber modified asphalt.

  15. PHA-rubber blends: synthesis, characterization and biodegradation.

    Science.gov (United States)

    Bhatt, Rachana; Shah, Dishma; Patel, K C; Trivedi, Ujjval

    2008-07-01

    Medium chain length polyhydroxyalkanoates (mcl-PHA) and different rubbers; namely natural rubber, nitrile rubber and butadiene rubber were blended at room temperature using solution blending technique. Blends constituted 5%, 10% and 15% of mcl-PHA in different rubbers. Thermogravimetric analysis of mcl-PHA showed the melting temperature of the polymer around 50 degrees C. Thermal properties of the synthesized blend were studied by Differential Scanning Calorimetry which confirmed effective blending between the polymers. Blending of mcl-PHA with natural rubber led to the synthesis of a different polymer having the melting point of 90 degrees C. Degradation studies of the blends were carried out using a soil isolate, Pseudomonas sp. 202 for 30 days. Extracellular protein concentration as well as OD660 due to the growth of Pseudomonas sp. 202 was studied. The degradation of blended plastic material, as evidenced by % weight loss after degradation and increase in the growth of organism correlated with the amount of mcl-PHA present in the sample. Growth of Pseudomonas sp. 202 resulted in 14.63%, 16.12% and 3.84% weight loss of PHA:rubber blends (natural, nitrile and butadiene rubber). Scanning electron microscopic studies after 30 days of incubation further confirmed biodegradation of the films.

  16. Blends of guayule natural rubber latex with commercial latex polymers

    Science.gov (United States)

    Guayule (Parthenium argentatum) is a woody desert shrub that produces natural rubber, cis-1,4 polyisoprene, by biosynthesis. It is currently cultivated in the southwestern United States as a source of latex and rubber for commercial development. Guayule latex is similar to Hevea latex in polymer mo...

  17. A study of amino acid modifiers in guayule natural rubber

    Science.gov (United States)

    Natural rubber from the Hevea tree is a critical agricultural material vital to United States industry, medicine, and defense, yet the country is dependent on imports to meet domestic needs. Guayule, a desert shrub indigenous to the US, is under development as an alternative source of natural rubber...

  18. 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

  19. Flexible protective diamond-like carbon film on rubber

    NARCIS (Netherlands)

    Pei, Y.T.; Bui, X.L.; Hosson, J.Th.M. De

    2010-01-01

    In this paper we report an experimental approach to deposit flexible diamond-like carbon (DLC) films on rubber via self-segmentation. By making use of the substantial thermal mismatch between the DLC film and rubber substrate a dense network of cracks forms in the DLC film, contributing to its flexi

  20. 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.

  1. Top 10 News of China Rubber Industry in 2011

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    1 Price of Rubber Raw Materials Greatly Fluctuated, Cost of Enterprises Hard to Be Controlled In 2011, the price of raw materials such as rubber fluctuated greatly. In the first quarter, NR hit the highest historical record of 43,500 yuan/ton.

  2. Influence of Plasma Treatments on the Frictional Performance of Rubbers

    NARCIS (Netherlands)

    Wolthuizen, D.J.; Martinez-Martinez, D.; Pei, Y.T.; Hosson, J.Th.M. De

    2012-01-01

    The frictional performance of several rubbers after pulsed-DC plasma treatments has been examined. In all cases, the treated rubbers showed better performance than the corresponding untreated ones. Stronger treatments, in terms of longer process time and/or higher substrate bias voltage, led to larg

  3. Viscoelastic properties of short aramid fibres-reinforced rubbers

    NARCIS (Netherlands)

    Sadatshirazi, S.; Talma, Auke; Noordermeer, Jacobus W.M.

    2013-01-01

    Among short fiber-reinforced composites, those with rubber matrices have gained great importance due to the advantages they have in processing and low cost, coupled with high strength. These composites combine the elastic behavior of rubbers with strength and stiffness of fibers. Reinforcement with

  4. Reinforcement of latex rubber by the incorporation of amphiphilic nanoparticles

    Science.gov (United States)

    Latex rubbers are fabricated from latex suspensions. During the fabrication process, latex particles are bound together while water is removed from the suspension. This report shows the mechanical properties of latex rubbers can be improved by incorporating a small amount of amphiphilic nanoparticle...

  5. An overview of the potentials of natural rubber (Hevea brasiliensis ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-29

    Dec 29, 2009 ... Rubber grows well in deciduous rain-forest regions of lowland tropics with temperature ranges of between 21. - 35°C and a well distributed .... In the bark of the rubber tree is a complex network of laticifers, or latex vessels, ... develop into embryo-like structures that go on to form plantlets. MULTIPLYING ...

  6. Guayule resin detection and influence on guayule rubber

    Science.gov (United States)

    Guayule (Parthenium argentatum) is a natural rubber (cis-1,4-polyisoprene) producing crop, native to North America. Guayule also produces organic resins, complex mixtures of terpenes, triglycerides, guayulins, triterpenoids and other components. During natural rubber extraction, guayule resins can b...

  7. Lifetime of metal rubber isolator with different vibration amplitudes

    Institute of Scientific and Technical Information of China (English)

    JIANG Hong-yuan; XIA Yu-hong; AO Hong-rui; DONG Chun-fang; A.M.Ulanov

    2005-01-01

    The lifetime of metal rubber isolator and its characteristics during lifetime experiment were studied. The stepped-up test principle was adopted to study the lifetime of resonant frequency, the breakage form of metal rubber isolator was obtained, and the relation between the energy dissipation, resonant frequency and stiffness was obtained in available lifetime of the isolator. Furthermore, the reason for the changes of properties of metal rubber isolator was analyzed with contact model of metal rubber material. The results show that if the resonant amplitude is large, the stiffness of metal rubber isolator will be kept steadily for a long time, its resonant frequency will be stable and the effective working time in the protecting area will be long. The lifetime of metal rubber isolator is more than 1 376 h in the experiment. The main failure forms of metal rubber isolator are accumulative wear and breaking of metal wires and spirals. In protecting area the metal rubber isolator can work effectively for a long time, and the effective working time depends on the concrete working condition.

  8. Viscoelastic properties of short aramid fibres-reinforced rubbers

    NARCIS (Netherlands)

    Shirazi, S.; Talma, A.G.; Noordermeer, J.W.M.

    2013-01-01

    Among short fiber-reinforced composites, those with rubber matrices have gained great importance due to the advantages they have in processing and low cost, coupled with high strength. These composites combine the elastic behavior of rubbers with strength and stiffness of fibers. Reinforcement with

  9. Cohesion in crumb rubber modified bitumen

    Directory of Open Access Journals (Sweden)

    Páez Dueñas, A.

    2006-12-01

    Full Text Available This article reports on a study of crumb rubber-mediated improvement in bitumen cohesion, analyzed with the UCL method. UCL, a procedure developed to characterize bituminous binders, evaluates the cohesion obtained by adding a certain amount of bitumen or bituminous mastic to a standard mix aggregate. This method was chosen because it can be used to assess bitumen containing crumb rubber added by either the wet or the dry mix process. In the dry mix process crumb rubber is combined with the mix as if it were a fine aggregate; i.e., crumb rubber and binder are blended during mix manufacture, laying and compaction. In the wet mix process, the binder is blended with the crumb rubber prior to mixing with the aggregate; i.e., when added to the mix, it has already been modified. The effect of digesting this dry mixed material prior to use was also analyzed in the present study. A comparison of the dry (with and without digestion and wet mix processes showed the latter to be more effective, particularly when the crumb rubber was blended with the binder via microscopic dispersion.El objetivo de este artículo es estudiar la influencia del polvo de neumático en la mejora de la cohesión proporcionada por la adición del polvo de neumático al betún mediante el método UCL. El método UCL es un procedimiento desarrollado para caracterizar ligantes bituminosos, basado en la evaluación de la cohesión dada por una cantidad determinada de un betún o un mástico bituminoso a unos áridos de granulometría establecida (mezcla patrón. Se ha empleado este método porque permite valorar al mismo tiempo los dos procedimientos de incorporación del polvo de neumático al betún: vía seca y vía húmeda.El procedimiento seco se lleva a cabo añadiendo el polvo de neumático a la mezcla como si fuera un filler, de modo que el polvo de neumático y el ligante se mezclan durante la fabricación, extendido y compactación de la mezcla. En el procedimiento h

  10. COMPRESSIVE AND SHEAR ANALYSIS OF RUBBER BLOCK UNDER LARGE STRAIN

    Directory of Open Access Journals (Sweden)

    K. Sridharan

    2013-01-01

    Full Text Available The Elastomeric materials have found use in a wide range of applications, including hoses, tires, gaskets, seals, vibration isolators, bearings and dock fenders. The analysis of rubber blocks for its compression and shear behavior has been carried out using the imaging techniques. The dynamic stressing and its associated change in shape of the rubber blocks during large compression are very limited as their measurements were difficult. A newly developed Machine Vision based image processing test has been effectively used to study the deformation characteristics of the rubber blocks under large strains. An extended analysis on the rubber blocks has been carried out to understand the compression and deformation behavior in static and dynamic condition and the nonlinear behavior were also characterized. The rubber blocks of distinguished geometries have shown diverse change in shape and nonlinear deformation behavior under compression/shear loading.

  11. Dynamic simulation on rubber spring supporting equipment of vibrating screen

    Institute of Scientific and Technical Information of China (English)

    SU Rong-hua; PENG Chen-yu

    2011-01-01

    By ANSYS, dynamic simulation analysis of rubber spring supporting equipment used in vibrating screen was made. The modal frequency, mode, and harmonic displacement under working frequency were obtained. Variation of rubber spring supporting equipment's dynamic performance was discussed first, which is under the condition of existing spring stiffness difference and exciting force bias. Also, the quantitative calculation formulas were given. The results indicate that the performance of vibrating screen is closely related with rubber spring supporting equipment's dynamic performance. Differences of springs' stiffness coefficients reduce the modal frequency reduced, decrease the dynamic stiffness, and increase vibration displacement. Exciting force bias induces a larger lateral displacement. When rubber springs' stiffness coefficients exist, differences and lateral force accounts for 5% in total exciting force; rubber spring supporting equipment's side swing is larger than 1 mm, exceeding the side swing limit.

  12. Analysis of impact of suspension rubber mounts on ride comfort

    Science.gov (United States)

    Chen, Bao; Chen, Zheming; Lei, Gang

    2017-01-01

    Two multi-body car models with rubber mounts and without rubber mounts have been built up to research how the suspension rubber mounts impact ride comfort. The comfort mount was used to simulate the impact process. Two scenarios have been set up, and time integrations have been performed to get the acceleration-time histories of seat surface in the x-, y-, and z-direction. A MATLAB program was compiled to calculate the weighted RMS acceleration. For the first scenario, the relative difference of weighted RMS acceleration between the car models with rubber mounts and without rubber mounts gradually decreases as the road roughness increases. For the second scenario, the relative difference increases as the driving speed increases. The conclusion shows that the change of driving speed or road roughness impacts ride comfort. Especially for high driving speed this impact is quite obvious.

  13. 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.

  14. 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.

  15. Performance of the Cement Matrix Composite Material With Rubber Powder

    Institute of Scientific and Technical Information of China (English)

    SONG Shao-min; LIU Juan-hong; ZHANG Xi-qing

    2004-01-01

    The effect of the deferent rubber content substituted for fine aggregate on the mortar performancewas studied. The effects of the rubber coated with the coating materials on the mortar compressive strength, bendingstrength and impact work were discussed. The optimum rubber powder content and the suitable coating materialwere found. Through the electrical probe test- BEI, SEI and calcium ion distribution, and the slight crack and theinterface between the rubber and cement matrix are analyzed. The results show that the rubber powder coated withthe surface treatment materials A, B and C bas the capability of absorbing a large amount of energy under thecompressive and flexural load and the slight cracks of R- C were controlled and restrained.

  16. Reinforcement of rubber by fractal aggregates

    Science.gov (United States)

    Witten, T. A.; Rubinstein, M.; Colby, R. H.

    1993-03-01

    Rubber is commonly reinforced with colloidal aggregates of carbon or silica, whose structure has the scale invariance of a fractal object. Reinforced rubbers support large stresses, which often grow faster than linearly with the strain. We argue that under strong elongation the stress arises through lateral compression of the aggregates, driven by the large bulk modulus of the rubber. We derive a power-law relationship between stress and elongation λ when λgg 1. The predicted power p depends on the fractal dimension D and a second structural scaling exponent C. For diffusion-controlled aggregates this power p should lie beween 0.9 and 1.1 ; for reaction-controlled aggregates p should lie between 1.8 and 2.4. For uniaxial compression the analogous powers lie near 4. Practical rubbers filled with fractal aggregates should approach the conditions of validity for these scaling laws. On renforce souvent le caoutchouc avec des agrégats de carbone ou de silice dont la structure a l'invariance par dilatation d'un objet fractal. Les caoutchoucs ainsi renforcés supportent de grandes contraintes qui croissent souvent plus vite que l'élongation. Nous prétendons que, sous élongation forte, cette contrainte apparaît à cause d'une compression latérale des agrégats induite par le module volumique important du caoutchouc. Nous établissons une loi de puissance reliant la contrainte et l'élongation λ quand λgg 1. Cet exposant p dépend de la dimension fractale D et d'un deuxième exposant structural C. Pour des agrégats dont la cinétique de formation est limitée par diffusion, p vaut entre 0,9 et 1,1. Si la cinétique est limitée par le soudage local des particules, p vaut entre 1,8 et 2,4. Sous compression uniaxiale, les puissances homologues valent environ 4. Des caoutchoucs pratiques chargés de tels agrégats devraient approcher des conditions où ces lois d'échelle sont valables.

  17. On the inflation of a rubber balloon

    Science.gov (United States)

    Vandermarlière, Julien

    2016-12-01

    It is a well-known fact that it is difficult to start a balloon inflating. But after a pressure peak that occurs initially, it becomes far easier to do it! The purpose of this article is to establish the experimental pressure-radius chart for a rubber balloon and to compare it to the theoretical one. We will demonstrate that the barometer of a smartphone is a very suitable tool to reach this goal. We hope that this phenomenon will help students realize that sometimes very simple questions can lead to very interesting and counterintuitive science.

  18. Demotivating factors influencing rubber production workers

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Iravani

    2012-01-01

    Full Text Available Motivation is one of the most important factors influencing workers' productivity. An increase in workers' motivation could add more value to organizations' structure and influence the profitability, significantly. In this paper, we study different factors on demotivating workers using questionnaire consist of various questions. The questionnaire is distributed among some employees who work for rubber production units located in Esfahan, Iran. The results of this survey indicate that discrimination on annual job compensation, entrusting responsibilities and unpleasant relationship with family partner are some of the most important factors influencing employees' motivation. While financial factors play important role on increasing employees' motivation, non-financial factors are considered more important.

  19. Characterization of Hexsyn, a polyolefin rubber.

    Science.gov (United States)

    McMillin, C R

    1987-07-01

    Hexsyn is the Goodyear Tire and Rubber Company tradename for a polyolefin rubber synthesized from 1-hexene with 3-5% methylhexadiene as the source of residual double bonds for vulcanization. Under license from Goodyear, this same polymer has been manufactured by Lord Corporation for the hinge portion of finger joint prostheses using the tradename Bion. This rubber is currently licensed to the University of Akron and to the Cleveland Clinic Foundation for use in biomedical applications, and is being used primarily for biocompatible and highly fatigue resistant rubber components in ventricular assist and artificial heart systems. Results are presented from the physical, mechanical, and biological characterization of Hexsyn. Procedures are described for the synthesis, compounding, and post-molding extraction for Hexsyn. The physical testing of Hexsyn reported includes determinations of its density at 23 and 37 degrees C, initial hardness and hardness after aging in oxygen, blood, pseudoextracellular fluid and polyethylene glycol 600, typical molecular weights determined by gel permeation chromatography/low angle laser light scattering and intrinsic viscosity, thermal analyses by differential scanning calorimetry of Hexsyn gum, and vulcanized Hexsyn after exposure to blood and blood/fatigue conditions. Also reported are results of differential thermal analyses, thermomechanical analyses of virgin and annealed samples, and thermogravimetric analyses conducted in helium and in air. Dynamic mechanical analyses of Hexsyn include Clash-Berg and Rheovibron tests. Swelling was conducted to determine lot-to-lot and sheet-to-sheet variation for quality control and also a number of solvents were used so that the polymer-solvent interaction parameters could be determined. The permeability of Hexsyn to water, water vapor, and a variety of gases is reported. The permeability by contact angle measurements, refractive index, residual solvent analyses, migration of blood components

  20. 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.

  1. Bending and torsional vibrations of open tube booms on spinning spacecraft

    Science.gov (United States)

    Juang, J. N.; Davis, R.

    1977-01-01

    The mathematical formulation is presented of the coupled bending and twisting equations of motion for open tube booms in spinning spacecraft. The equations are applicable to a general class of open tube booms whose shear center does not coincide with the centroid of the cross section. The emphasis in this paper is on the treatment of the coupled bending and twisting motions. The equations of motion of the center of mass are provided in other references. The results of a simulation of the bending and twisting motion of a circular cross-section boom having a small longitudinal slot on a spinning spacecraft is provided. The simulation demonstrates that the centrifugal forces will induce twisting motion due to offset shear center.

  2. A Numerical Method of Large-Scale Concrete Displacing Boom Dynamic and Experimental Validation

    Directory of Open Access Journals (Sweden)

    Wu Ren

    2014-01-01

    Full Text Available Concrete displacing boom is large-scale motion manipulator. During the long distance pouring the postures needs to frequently change. This makes the real-time dynamic analysis and health monitoring difficult. Virtual spring-damper method is adopted to establish the equivalent hydraulic actuator model. Besides boom cylinder joint clearance is taken into account. Then transfer matrix method is used to build the multibody concrete placing boom model by dividing the system into two substructures. Next typical working conditions displacements and accelerations during the pouring process are studied. The results of the numerical method are correct and feasible compared with Recurdyn software and the experimental ones. So it provides reference to the real-time monitoring and structure design for such light weight large scale motion manipulators.

  3. 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.

  4. Properties of Concrete Containing Scrap-Tire Rubber

    Directory of Open Access Journals (Sweden)

    Mazyad Al-Fadhli

    2017-03-01

    Full Text Available Solid waste management is one of the major environmental concerns all over the world and in Kuwait. Over 5 billion tons of non-hazardous solid waste materials are generated in Kuwait each year. Of these, more than 2 million scrap-tires (approximately 2 million tons are generated each year. In addition to this, about seven million scrap-tires have been stockpiled. 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 10%, 15%, 20%, and 25% 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.

  5. Statistical Discrimination of Latex between Healthy and White Root Infected Rubber Tree based on Dry Rubber Content

    Science.gov (United States)

    Suhaimi Sulaiman, Mohd; Hashim, Hadzli; Faiz Mohd Sampian, Ahmad; Korlina Madzhi, Nina; Faris Mohd Azmi, Azrie; Aishah Khairuzzaman, Noor; Aima Ismail, Faridatul

    2015-11-01

    Dry rubber content (DRC) is one of main material existing inside latex. It is usually in ranged of 25% - 45% of rubber latex. Statistical analysis are done to determine the discrimination of dry rubber content of latex between healthy and white root infected rubber tree. Based on 150 rubber trees and 10 clones tested, parametric test which include normality test, error-bar plot, and paired samples test are done. The result outcomes have shown that both data of dry rubber content of latex for healthy and white root infected rubber tree are normally distributed. Error-bar plot test is clearly indicated that there is visible discrimination between both cases. Paired samples test are done to reinforce this findings in terms of numerical p- value which is found to be less than 0.05. Thus, this indicate overwhelming evidence that healthy group can be discriminated from white root. Conclusively, changes in DRC content in latex can be correlated with white root disease infections of rubber tree.

  6. 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; 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.

  7. Flexible diamond-like carbon films on rubber : Friction and the effect of viscoelastic deformation of rubber substrates

    NARCIS (Netherlands)

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

    2012-01-01

    This paper focuses on the frictional behavior of flexible diamond-like carbon (DLC) film-coated hydrogenated nitrile butadiene rubber. By making use of the substantial thermal mismatch between DLC film and rubber substrate, a dense network of cracks forms in the DLC films and contributes to flexibil

  8. CAPITAL FLOWS, CONSUMPTION BOOMS AND ASSET BUBBLES: A BEHAVIOURAL ALTERNATIVE TO THE SAVINGS GLUT HYPOTHESIS.

    Science.gov (United States)

    Laibson, David; Mollerstrom, Johanna

    2010-05-01

    Bernanke (2005) hypothesized that a "global savings glut" was causing large trade imbalances. However, we show that the global savings rates did not show a robust upward trend during the relevant period. Moreover, if there had been a global savings glut there should have been a large investment boom in the countries that imported capital. Instead, those countries experienced consumption booms. National asset bubbles explain the international imbalances. The bubbles raised consumption, resulting in large trade deficits. In a sample of 18 OECD countries plus China, movements in home prices alone explain half of the variation in trade deficits.

  9. Design of Rail Instrumentation for Wind Tunnel Sonic Boom Measurements and Computational-Experimental Comparisons

    Science.gov (United States)

    Cliff, Susan E.; Elmiligui, A.; Aftosmis, M.; Morgenstern, J.; Durston, D.; Thomas, S.

    2012-01-01

    An innovative pressure rail concept for wind tunnel sonic boom testing of modern aircraft configurations with very low overpressures was designed with an adjoint-based solution-adapted Cartesian grid method. The computational method requires accurate free-air calculations of a test article as well as solutions modeling the influence of rail and tunnel walls. Specialized grids for accurate Euler and Navier-Stokes sonic boom computations were used on several test articles including complete aircraft models with flow-through nacelles. The computed pressure signatures are compared with recent results from the NASA 9- x 7-foot Supersonic Wind Tunnel using the advanced rail design.

  10. The secret of neuroscience boom: Are there secret human experiments in Latin América?

    Directory of Open Access Journals (Sweden)

    David Salinas Flores

    2016-01-01

    Full Text Available About 6 years ago there sparked a phenomenon in science called the neuroscientific boom. Neurologists underpin this phenomenon to cost reduction techniques such as electroencephalograms and to improved noninvasive technology such as functional MRI. But the human brain, the most complex organ in the universe, has not yet been fully investigated with the existing noninvasive technologies. Thus, there is a suspicion that the real reason for this boom is a secret, forced, and illicit human experimentation in Latin America. Physicians should investigate, be alert, and report these potential unethical human experiments to prevent any further damage to the public health of the citizens of Latin societies.

  11. Specialized CFD Grid Generation Methods for Near-Field Sonic Boom Prediction

    Science.gov (United States)

    Park, Michael A.; Campbell, Richard L.; Elmiligui, Alaa; Cliff, Susan E.; Nayani, Sudheer N.

    2014-01-01

    Ongoing interest in analysis and design of low sonic boom supersonic transports re- quires accurate and ecient Computational Fluid Dynamics (CFD) tools. Specialized grid generation techniques are employed to predict near- eld acoustic signatures of these con- gurations. A fundamental examination of grid properties is performed including grid alignment with ow characteristics and element type. The issues a ecting the robustness of cylindrical surface extrusion are illustrated. This study will compare three methods in the extrusion family of grid generation methods that produce grids aligned with the freestream Mach angle. These methods are applied to con gurations from the First AIAA Sonic Boom Prediction Workshop.

  12. Characterization of the wine boom in Mendoza (Argentina), 1904-1912

    OpenAIRE

    Barrio de Villanueva, Patricia

    2009-01-01

    En consonancia con el ritmo de crecimiento de la economía nacional, la vitivinicultura mendocina vivió, entre 1904 y 1912, un verdadero boom económico-productivo. En este artículo se presenta información de dicho fenómeno a través de algunas variables representativas del sector. En segundo lugar, se intenta reconstruir los costos de producción de uva y vino, y la probable rentabilidad de los actores vitivinícolas. Mendocinean viticulture experimented between 1904 and 1912 a booming economi...

  13. Understanding the expansion of energy crops beyond the global biofuel boom : evidence from oil palm expansion in Colombia

    NARCIS (Netherlands)

    Marin-Burgos, Victoria; Clancy, Joy S.

    2017-01-01

    Background: The global palm oil market experienced a remarkable boom since the year 2000. Since palm oil can be used for biodiesel production, the global expansion of oil palm cultivation has been associated with the global biofuel boom. Biofuel policies—especially those adopted in the European

  14. Characterization of the wine boom in Mendoza (Argentina, 1904-1912 Caracterización del boom vitivinícola en Mendoza (Argentina, 1904-1912

    Directory of Open Access Journals (Sweden)

    Patricia Barrio de Villanueva

    2009-01-01

    Full Text Available Mendocinean viticulture experimented between 1904 and 1912 a booming economical growth consistent with the national average growth. In this article we present the values of some variables that illustrate some representative indicators of that section of the economy. We attempt to reconstruct the production costs of grapes and wines and the possible revenues of the viticulture actorsEn consonancia con el ritmo de crecimiento de la economía nacional, la vitivinicultura mendocina vivió, entre 1904 y 1912, un verdadero boom económico-productivo. En este artículo se presenta información de dicho fenómeno a través de algunas variables representativas del sector. En segundo lugar, se intenta reconstruir los costos de producción de uva y vino, y la probable rentabilidad de los actores vitivinícolas

  15. Rubber hand illusion affects joint angle perception.

    Directory of Open Access Journals (Sweden)

    Martin V Butz

    Full Text Available The Rubber Hand Illusion (RHI is a well-established experimental paradigm. It has been shown that the RHI can affect hand location estimates, arm and hand motion towards goals, the subjective visual appearance of the own hand, and the feeling of body ownership. Several studies also indicate that the peri-hand space is partially remapped around the rubber hand. Nonetheless, the question remains if and to what extent the RHI can affect the perception of other body parts. In this study we ask if the RHI can alter the perception of the elbow joint. Participants had to adjust an angular representation on a screen according to their proprioceptive perception of their own elbow joint angle. The results show that the RHI does indeed alter the elbow joint estimation, increasing the agreement with the position and orientation of the artificial hand. Thus, the results show that the brain does not only adjust the perception of the hand in body-relative space, but it also modifies the perception of other body parts. In conclusion, we propose that the brain continuously strives to maintain a consistent internal body image and that this image can be influenced by the available sensory information sources, which are mediated and mapped onto each other by means of a postural, kinematic body model.

  16. INDUSTRIAL SAFETY IN THE PRODUCTION OF RUBBER

    Directory of Open Access Journals (Sweden)

    S. V. Danilova

    2015-01-01

    Full Text Available Russian industry of synthetic rubber, is one of the most competitive and occupies a prominent place in the global petrochemical industry. However, the company production of synthetic rubber are among the most hazardous industrial facilities. The main operational risks are to fire and explosion hazards of raw materials used. Accidents in such establishments can damage not only the equipment, materials or buildings, but also cause serious environmental and economic consequences for the region. For the prevention of accidents, mitigation and elimination of losses, it is necessary to apply a set of measures aimed at the management and control of industrial safety. The legal basis of industrial safety in the Russian Federation is the Federal Law № 116-FZ dated 21.07.97 "On industrial safety of hazardous production facilities." Industrial Safety at work an important part of its normal functioning. The most important condition of industrial safety of hazardous production facilities is the examination of industrial safety. Federal rules and regulations in the field of industrial safety "rules of examination of industrial safety", approved by Order of RTN on November 14, 2013 N 538 established: the procedure of examination of industrial safety requirements for the design of expert opinions and requirements for experts.

  17. Pyrolysis of Rubber in a Screw Reactor

    Science.gov (United States)

    Lozhechnik, A. V.; Savchin, V. V.

    2016-11-01

    On the basis of an analysis of thermal methods described in the literature and from the results of experimental investigations of steam conversion, the authors have developed and created a facility for thermal processing of rubber waste. Rubber crumb was used as the raw material; the temperature in the reactor was 500°C; nitrogen, steam, and a mixture of light hydrocarbons (noncondensable part of pyrolysis products) represented the working medium. The pyrolysis yielded 36-38% of a solid fraction, 54-56% of a liquid hydrocarbon fraction, and 6-9% of noncondensable gases. Changes in the composition of the gas mixture have been determined at different stages of processing. Gas chromatography of pyrolysis gases has shown that the basic gases produced by pyrolysis are H2 and hydrocarbons C2H4, C3H6, C3H8, C4H8, C2H6, C3H6O2, and C4H10, and a small amount of H2S, CO, and CO2. Noncondensable gases will be used as a fuel to heat the reactor and to implement the process.

  18. Plant and bird diversity in rubber agroforests in the lowlands of Sumatra, Indonesia

    NARCIS (Netherlands)

    Beukema, Hendrien; Danielsen, Finn; Vincent, Gregoire; Hardiwinoto, Suryo; van Andel, Jelte

    Plant and bird diversity in the Indonesian jungle rubber agroforestry system was compared to that in primary forest and rubber plantations by integrating new and existing data from a lowland rain forest area in Sumatra. Jungle rubber gardens are low-input rubber (Hevea brasiliensis) agroforests that

  19. Plant and bird diversity in rubber agroforests in the lowlands of Sumatra, Indonesia

    NARCIS (Netherlands)

    Beukema, Hendrien; Danielsen, Finn; Vincent, Gregoire; Hardiwinoto, Suryo; van Andel, Jelte

    2007-01-01

    Plant and bird diversity in the Indonesian jungle rubber agroforestry system was compared to that in primary forest and rubber plantations by integrating new and existing data from a lowland rain forest area in Sumatra. Jungle rubber gardens are low-input rubber (Hevea brasiliensis) agroforests that

  20. 40 CFR 428.30 - Applicability; description of the solution crumb rubber subcategory.

    Science.gov (United States)

    2010-07-01

    ... solution crumb rubber subcategory. 428.30 Section 428.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Solution Crumb Rubber Subcategory § 428.30 Applicability; description of the solution crumb rubber...

  1. 75 FR 51981 - Polychloroprene Rubber from Japan: Final Results of Sunset Review and Revocation of Finding

    Science.gov (United States)

    2010-08-24

    ... International Trade Administration Polychloroprene Rubber from Japan: Final Results of Sunset Review and... review of the antidumping finding on polychloroprene rubber from Japan. Because the domestic interested... polychloroprene rubber from Japan. See Polychloroprene Rubber from Japan, 38 FR 33593 (December 6, 1973)....

  2. 40 CFR 428.40 - Applicability; description of the latex rubber subcategory.

    Science.gov (United States)

    2010-07-01

    ... latex rubber subcategory. 428.40 Section 428.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex Rubber Subcategory § 428.40 Applicability; description of the latex rubber subcategory. The provisions...

  3. 40 CFR 428.20 - Applicability; description of the emulsion crumb rubber subcategory.

    Science.gov (United States)

    2010-07-01

    ... emulsion crumb rubber subcategory. 428.20 Section 428.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Emulsion Crumb Rubber Subcategory § 428.20 Applicability; description of the emulsion crumb rubber...

  4. 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

  5. The dynamics and optimal control of spinning spacecraft with movable telescoping appendages. Part C: Effect of flexibility during boom deployment

    Science.gov (United States)

    Bainum, P. M.; James, P. K.

    1977-01-01

    The dynamics of a spinning symmetrical spacecraft system during the deployment (or retraction) of flexible boom-type appendages were investigated. The effect of flexibility during boom deployment is treated by modelling the deployable members as compound spherical pendula of varying length (according to a control law). The orientation of the flexible booms with respect to the hub, is described by a sequence of two Euler angles. The boom members contain a flexural stiffness which can be related to an assumed effective restoring linear spring constant, and structural damping which effects the entire system. Linearized equations of motion for this system, when the boom length is constant, involve periodic coefficients with the frequency of the hub spin. A bounded transformation is found which converts this system into a kinematically equivalent one involving only constant coefficients.

  6. Influence of temperature changes on torsional rigidity and damping coefficient of rubber torsional vibration damper

    Directory of Open Access Journals (Sweden)

    Wojciech HOMIK

    2011-01-01

    Full Text Available The short explanation of usefulness of rubber torsional dampers in crankshaft in multi-cylinder engines is presented. The description of the construction and operation of rubber torsional damper is also included. In the rubber torsional damper, the damping is achieved as the effect of internal friction resulting from the deformation of the rubber material. This deformation appears while the internal rubber elasticity is overloaded. Both the physical and mechanical rubber properties depend on temperature change. In cooperation with rubber dampers manufacturer the experimental investigations are made in order to establish the influence of temperature change on torsional stiffness and damping.

  7. Enhancement of Adhesion between EPDM and Polyester Fabric by Using Natural Rubber Modified by Maleic Anhydride

    Directory of Open Access Journals (Sweden)

    A. A. El-Wakil

    2011-01-01

    Full Text Available This study presents a new method for improving adhesion between ethylene propylene diene monomer (EPDM rubber and polyester fabric. In this work, natural rubber was modified by maleic anhydride in order to improve the adhesion force between ethylene propylene diene monomer rubber and polyester fabric. The effect of thermal aging and ionizing radiation on the stability of the rubber mix as well as on the peel strength of the rubber-coated fabric was investigated. It was observed that the natural rubber modified by maleic anhydride improved the peel strength of the EPDM rubber-coated polyester fabric.

  8. Comparative studies on crosslinked and uncrosslinked natural rubber biodegradation by Pseudomonas sp.

    Science.gov (United States)

    Roy, Ram Vinod; Das, Mithu; Banerjee, Rintu; Bhowmick, Anil K

    2006-12-01

    A comparative study on biodegradation of di-cumyl peroxide (DCP) crosslinked and uncrosslinked natural rubber by Pseudomonas sp. was carried out. Decrease in organic carbon content along with the changes in tensile strength of the treated rubber, both DCP crosslinked and uncrosslinked natural rubber, indicated rubber hydrocarbon utilization by the Pseudomonas sp. A decrease in 60.88% MPa and 41.66% MPa was observed after five month's old treated uncrosslinked natural rubber and DCP crosslinked rubber, respectively. Biodegradation was more pronounced in natural uncrosslinked rubber, which was further confirmed by the formation of aldehydic compounds with decrease in CH2 stretching frequencies.

  9. Material and Flexural Properties of Fiber-reinforced Rubber Concrete

    Science.gov (United States)

    Helminger, Nicholas P.

    The purpose of this research is to determine the material properties of rubber concrete with the addition of fibers, and to determine optimal mixture dosages of rubber and fiber in concrete for structural applications. Fiber-reinforced concrete and rubberized concrete have been researched separately extensively, but this research intends to combine both rubber and fiber in a concrete matrix in order to create a composite material, fiber-reinforced rubber concrete (FRRC). Sustainability has long been important in engineering design, but much of the previous research performed on sustainable concrete does not result in a material that can be used for practical purposes. While still achieving a material that can be used for structural applications, economical considerations were given when choosing the proportions and types of constituents in the concrete mix. Concrete mixtures were designed, placed, and tested in accordance with common procedures and standards, with an emphasis on practicality. Properties that were investigated include compressive strength, tensile strength, modulus of elasticity, toughness, and ductility. The basis for determining the optimal concrete mixture is one that is economical, practical, and exhibits ductile properties with a significant strength. Results show that increasing percentages of rubber tend to decrease workability, unit weight, compressive strength, split tensile strength, and modulus of elasticity while the toughness is increased. The addition of steel needle fibers to rubber concrete increases unit weight, compressive strength, split tensile strength, modulus of elasticity, toughness, and ductility of the composite material.

  10. Mechanical properties and durability of crumb rubber concrete

    Science.gov (United States)

    Chylík, Roman; Trtík, Tomáš; Fládr, Josef; Bílý, Petr

    2017-09-01

    This paper is focused on concrete with admixture of rubber powder, generally called crumb rubber concrete (CRC). The inspiration was found in Arizona, where one of the first CRCs has been created. However, Arizona has completely different climates than Central Europe. Could we use the crumb rubber concrete on construction applications in the Central European climate too? The paper evaluates the influence of the rubber powder on material characteristics and durability of CRC. CRCs with various contents of fine and coarse crumb powder were compared. The tested parameters were slump, air content, permeability, resistance of concrete to water with deicing chemicals, compressive and splitting tensile strength. The tests showed that workability, compressive strength and permeability decreased as the amount of rubber increased, but the air content increased as the rubber content increased. Photos of air voids in cement matrix from electron microscope were captured. The results of laboratory tests showed that admixture of rubber powder in concrete could have a positive impact on durability of concrete and concurrently contribute to sustainable development. Considering the lower compressive strength, CRC is recommended for use in applications where the high strength of concrete is not required.

  11. Characterization of associated proteins and phospholipids in natural rubber latex.

    Science.gov (United States)

    Sansatsadeekul, Jitlada; Sakdapipanich, Jitladda; Rojruthai, Porntip

    2011-06-01

    Non-rubber components present in natural rubber (NR) latex, such as proteins and phospholipids, are presumed to be distributed in the serum fraction as well as surrounding the rubber particle surface. The phospholipid-protein layers covering the rubber particle surface are especially interesting due to their ability to enhance the colloidal stability of NR latex. In this study, we have characterized the components surrounding the NR particle surface and investigated their role in the colloidal stability of NR particles. Proteins from the cream fraction were proteolytically removed from the NR latex and compare to those from the serum fractions using SDS-polyacrylamide gel electrophoresis revealing that both fractions contained similar proteins in certain molecular weights such as 14.5, 25 and 27 kDa. Phospholipids removed from latex by treatment with NaOH were analyzed using (1)H-NMR spectroscopy and several major signals were assignable to -(CH(2))(n)-, -CH(2)OP, -CH(2)OC═O and -OCH(2)CH(2)NH-. These signals are important evidence that indicates phospholipids associate with the rubber chain. The colloidal behavior of rubber lattices before and after removal of protein-lipid membrane was evaluated by zeta potential analysis and scanning electron microscope (SEM). The lowest zeta potential value of NR particles was observed at pH 10, consequently leading to the highest stability of rubber particles. Additionally, SEM micrographs clearly displayed a gray ring near the particle surface corresponding to the protein-lipid membrane layer.

  12. Microcellular foaming of silicone rubber with supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hong, In-Kwon; Lee, Sangmook [Dankook University, Youngin (Korea, Republic of)

    2014-01-15

    In spite of great concern on the industrial application of microcellular silicone rubber foams, such as in electric and medical devices, only a few works can be found about the foaming of silicone rubber. In this study, microcellular silicone rubber foams with a cell size of 12 µm were successfully prepared with curing by heat and foaming by supercritical CO{sub 2} as a green blowing agent. The microcellular silicone rubber foams exhibited a well-defined cell structure and a uniform cell size distribution. The crosslinking and foaming of silicone rubber was carried out separately. After foaming, the silicone rubber foam was cross-linked again to stabilize the foam structure and further improve its mechanical properties. Foaming process of cross-linked silicone rubber should be designed carefully based on the viscoelastic properties because of its elastic volume recovery in the atmosphere. The basic crosslinking condition for small cell size and high cell density was obtained after investigating the rheological behavior during crosslinking.

  13. Volume Changes in Filled Rubber Under Uniaxial Cyclic Loading

    Directory of Open Access Journals (Sweden)

    Elina KAZINA

    2011-09-01

    Full Text Available Styrene-butadiene rubber, neat and filled with different silica content was investigated under uniaxial cyclic loading under a constant crosshead speed, with increasing deformation amplitude in subsequent loading cycles. Rubber was investigated in order to evaluate the reversibility of structure rearrangements, occurring in rubber when subjected to cyclic loading. Volume uniformly increases with growing strain and shows hysteresis at unloading. After complete unloading, no residual strain changes are observed. These data are in good conformity with the data of density measurements, which were made on specimens before and after the tests. By correlating data, obtained from volume changes and kinetics of hysteresis losses there were made assumptions on deformation mechanisms at different elongations. Deformational mechanisms, responsible for volume changes in rubber are reversible. Volume changes in specimen occur due to voids formation caused by filler microstructure breakage, rubber chains disentanglement, spaces between rubber macromolecular chains shrinkage, and chain slippage under higher elongations. Voids formation and deformation of rubber macromolecular chain reaches equilibrium state after certain elongation.http://dx.doi.org/10.5755/j01.ms.17.3.592

  14. The Abrasion-resistance Investigation of Rubberized Concrete

    Institute of Scientific and Technical Information of China (English)

    KANG Jingfu; ZHANG Bo; LI Guangyu

    2012-01-01

    The abrasion resistance properties of rubberized concrete were comparatively studied by taking silica fume and crumb tire rubber as the additives.The abrasion tests were conducted in accordance with the Chinese standard test method DL/T 5150-2001,two recommended test methods:under water method and ring method,were used.The crumb tire rubbers with the sieve size of 8-mesh and 16-mesh were incorporated into the concrete by replacing same volume of sand and as an additive.The abrasion resistance of concrete was evaluated according to the abrasion resistance strength and the mass loss.Test results show that the addition of silica fume enhanced both compressive strength and abrasion resistance of concrete,and the addition of crumb rubber reduced the compressive strength but increased notably the abrasion resistance of the concrete.Silica fume concrete performed a better abrasion resistance than control concrete,and the rubberized concrete performed a much better abrasion resistance than silica fume concrete.The abrasion resistance of rubberized concrete increased with the increase of rubber content.

  15. 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.

  16. 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.

  17. [Netherlands Fertility Survey 1982: women from the postwar baby boom].

    Science.gov (United States)

    Beets Gcn; Zakee, F P

    1984-10-01

    This article comprises some results of the Netherlands Fertility Survey 1982 (NFS '82) but only for those women born between 1945-49. For the most part, these women, about age 35 at the time of interview, are the result of a postwar baby boom. Of all the respondents (the entire survey comprised a sample of women born between 1945-64), this generation had the greatest demographic experience. Thus the survey provides additional information on differentials of cohabitation, nuptiality, fertility, and birth control which are not available readily from the integral population statistics. Population statistics have shown that in the Netherlands, women from the 1945-49 generation stood on the brink of a number of structural changes in the fields of relationship formation and childbearing. Marriage has lost some of its popularity; voluntary childlessness has been on the rise. In 1982, this generation numbered about 573,500 women in the Netherlands. Scheme 1 shows that by that time, 467,000 women (81%) were married for the 1st time; 11,000 (2%) for the 2nd time; 4000 were widowed; and 36,000 divorced. In all, 529,000 marriages had been contracted and 55,000 (10%) dissolved. The NFS '82 results further indicate that 73,000 women (13%) had ever cohabited. At the end of the interviews, 8000 never-married as well as 7000 formerly married women were cohabiting. From text table 3 it can be concluded that premarital cohabitation is no guarantee that marriage will be a success. The table (column 4) and graph 2 give information on the percentage of 1st marriages and the age at 1st marriage by background variables. Until 1982, these women had given birth to over 1 million children. About 90,000 women (16%) had not yet had a child. Graphs 3 and 4 present the age at childbearing by parity and background variables. As is the case for 1st marriages, the differentiation by education and parental family size is noteworthy. Almost all women had ever had a job but most of them stopped when

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

    OpenAIRE

    Hanbing Liu; Xianqiang Wang; Yubo Jiao; Tao Sha

    2016-01-01

    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 content...

  19. Experimental Investigation into Mechanical Properties of Nanomaterial-reinforced Table Tennis Rubber

    Directory of Open Access Journals (Sweden)

    Yu-Fen Chen

    2016-10-01

    Full Text Available A new table tennis rubber is prepared consisting of carbon nanotubes, zinc oxide and titanium oxide added to a mixture of natural and synthesized rubber. The Nano-reinforced rubber is attached to wooden table tennis blades and patterned with four different surface structures, namely flat, long pimples, short pimples and medium pimples. The results show that of the five rubbers, the Nano-reinforced rubber with a flat surface offers a significantly improved elastic and mechanical performance

  20. Interplanting banana at high densities with immature rubber crop for improved water use

    OpenAIRE

    Harischandra Lakshman Rodrigo, Vitharanage; Maeve Stirling, Clare; Teklehaimanot, Zewge; Kusum Samarasekera, Renuka; Dharmasiri Pathirana, Pathiranage

    2005-01-01

    International audience; Consumptive water use of the rubber/banana intercropping systems was assessed. Five systems were tested; sole rubber (R) and banana (B) crops and three intercrops comprising additive series of one (BR), two (BBR) and three (BBBR) rows banana to one row of rubber. Planting density of rubber remained constant across the treatments, hence the rate of transpiration associated closely with the planting density of banana with ca. 140% increase from banana-rubber to banana-ba...

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

    OpenAIRE

    Hanbing Liu; Xianqiang Wang; Yubo Jiao; Tao Sha

    2016-01-01

    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 content...

  2. 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.

  3. 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.

  4. 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.

  5. Radiation crosslinking of styrene-butadiene rubber containing waste tire rubber and polyfunctional monomers

    Science.gov (United States)

    Yasin, Tariq; Khan, Sara; Shafiq, Muhammad; Gill, Rohama

    2015-01-01

    The objective of this study was to investigate the influence of polyfunctional monomers (PFMs) and absorbed dose on the final characteristics of styrene-butadiene rubber (SBR) mixed with waste tire rubber (WTR). A series of SBR/WTR blends were prepared by varying the ratios of WTR in the presence of PFMs, namely trimethylolpropane trimethacrylate (TMPTMA) and trimethylolpropane triacrylate (TMPTA) and crosslinked using gamma rays. The physicochemical characteristics of the prepared blends were investigated. It was observed that tensile strength, hardness and gel content of the blends increased with absorbed dose while the blends containing TMPTA showed higher tensile strength, gel content and thermal stability as compared to the blends containing TMPTMA. Higher thermal stability was observed in the blends which were crosslinked by radiation as compared to the blends crosslinked by sulfur. These blends exhibited higher rate of swelling in organic solvents, whereas negligible swelling was observed in acidic and basic environment.

  6. 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.

  7. Development of a Method to Fingerprint Rubber Fuel Hose Materials

    Science.gov (United States)

    1990-10-01

    ASTM Method D297 . The EPA method was chosen because it is commonly performed in 89293.01F:RWT Page 1-7 these laboratories and is of a larger scale...5746, March, 1987. 3 Method for Rubber Products - Chemical Analysis, Annual Book of ASTM Standards, ASTM D297 -81, v. 09.01, 1984. 4 Method for Rubber...composition and materials of construction. 2. Applicable Documents 2.1 ASTM Standards D297 - Rubber Products - Chemical Analysis, Sec 16-18 D3421

  8. Short Fibre and Particulate-reinforced Rubber Composites

    Directory of Open Access Journals (Sweden)

    Kavita Agarwal

    2002-07-01

    Full Text Available Particulate fillers (carbon black and silica and short fibre (aromatic polyamide, Kevlar have been utilised to produce rubber composites based on acrylonitrile-co-butadiene rubber (NBR. Mechanical properties of these composites have been determined and compared with unfilled rubber vulcanisate. The effect of surface treatment on the improvement of strength, in case of Kevlar, has also been considered. The influence of elevated temperature on tear strength, an important failure criterion, has been evaluated. Scanning electron microscopy has been used as a tool to correlate the topographical features associated with changes in the tear strength of the composites.

  9. Shear Flow Induced Alignment of Carbon Nanotubes in Natural Rubber

    Directory of Open Access Journals (Sweden)

    Yan He

    2015-01-01

    Full Text Available A new procedure for the fabrication of natural rubber composite with aligned carbon nanotubes is provided in this study. The two-step approach is based on (i the preparation of mixture latex of natural rubber, multiwalled carbon nanotubes, and other components and (ii the orientation of carbon nanotubes by a flow field. Rubber composite sheets filled with variable volume fraction of aligned carbon nanotubes were fabricated and then confirmed by transmission electron microscopy and Raman spectroscopy studies. An obvious increase in thermal conductivity has been obtained after the alignment of carbon nanotubes. The dynamic mechanical analysis was carried out in a tear mode for the composite.

  10. 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

  11. Thermal and mechanical behavior of rubber systems

    Science.gov (United States)

    Macon, David James

    The study of the physical behavior of rubbery materials is motivated by the desire to use these materials in a variety of environments, different mechanical conditions, and at different temperatures. For this to be possible, accurate testing conditions and modeling schemes need to be devised. These tests can be difficult to perform and existing mathematical models often neglect several basic physical requirements. One model is the statistical thermodynamic approach for calculating the thermoelastic behavior of an ideal rubber network, which assumes affine deformation of crosslinked junctions and no internal energy change with isothermal deformation. Yet, when the same relations have been manipulated according to the laws of thermodynamics, an internal energy contribution is revealed. This result is an artifact of improperly referencing strain measures and elasticity coefficients with regard to temperature. When a proper strain reference state is selected, thermoelastic stress-strain-temperature relations result that are totally entropic yet reduce to the usual isothermal conditions. This work proposes a phenomenological model that accurately models existing thermoelastic data. Experimental methods to determine the entropic and energetic contributions to rubber elasticity usually focus on the force-temperature behavior of a uniaxial sample held at constant length. Ideally, these thermoelastic measurements would be made at constant volume. Measurements are made at constant pressure and require complex corrections. It is demonstrated that two dimensionally constrained membrane samples can overcome these difficulties. By using time-average vibrational holographic interferometry, the two principal stresses of a membrane in anisotropic biaxial extension can be directly determined as a function of temperature. This two dimensionally constrained stress-temperature response greatly simplifies the resulting mathematical relations and yields no difference between constant

  12. The role of pressure in rubber elasticity

    Science.gov (United States)

    Bower, A. F.; Weiner, J. H.

    2004-06-01

    We describe a series of molecular dynamics computations that reveal an intimate connection at the atomic scale between difference stress (which resists stretches) and pressure (which resists volume changes) in an idealized elastomer, in contrast to the classical theory of rubber elasticity. Our simulations idealize the elastomer as a "pearl necklace," in which the covalent bonds are stiff linear springs, while nonbonded atoms interact through a Lennard-Jones potential with energy εLJ and radius σLJ. We calculate the difference stress t11-(t22+t33)/2 and mean stress (t11+t22+t33)/3 induced by a constant volume extension in the x1 direction, as a function of temperature T and reduced density ρ*=NσIJ3/ν. Here, N is the number of atoms in the simulation cell and ν is the cell volume. Results show that for ρ*rubber elasticity, which neglects nonbonded interactions. However, data presented by van Krevelen [Properties of Polymers, 3rd ed. (Elsevier, Amsterdam, 1990), p. 79] indicate that rubber at standard conditions corresponds to ρ*=1.2. For ρ*>1, the system is entropic for kT/εLJ>2, but at lower temperatures the difference stress contains an additional energy component, which increases as ρ* increases and temperature decreases. Finally, the model exhibits a glass transition for ρ*=1.2 and kT/εLJ≈2. The atomic-scale processes responsible for generating stress are explored in detail. Simulations demonstrate that the repulsive portion of the Lennard-Jones potential provides a contribution σnbr>0 to the difference stress, the attractive portion provides σnba≈0, while the covalent bonds provide σb0, and Πb, σb=BΠb, where is a measure of the anisotropy of the orientation of the covalent bonds, and A and B are coefficients that depend weakly on ρ* and temperature. For high values of ρ*, we find that |σnbr|≫|σb|, and in this regime our model predicts behavior that is in good agreement with experimental data of D.L. Quested et al. [J. Appl. Phys. 52

  13. Prediction of sonic boom from experimental near-field overpressure data. Volume 2: Data base construction

    Science.gov (United States)

    Glatt, C. R.; Reiners, S. J.; Hague, D. S.

    1975-01-01

    A computerized method for storing, updating and augmenting experimentally determined overpressure signatures has been developed. A data base of pressure signatures for a shuttle type vehicle has been stored. The data base has been used for the prediction of sonic boom with the program described in Volume I.

  14. Changing Fortunes: How China’s Boom Caused the Financial Crisis

    NARCIS (Netherlands)

    H. Mees (Heleen)

    2012-01-01

    textabstractThis dissertation includes five academic papers that – one way or the other – all relate to China. The first paper delivers proof for the central thesis of this thesis, which is that China’s boom caused the 2008 financial crisis and ensuing recession. As much as I hoped from the outset

  15. 75 FR 49843 - Regulated Navigation Area; Boom Deployment Strategy Testing, Great Bay, NH

    Science.gov (United States)

    2010-08-16

    ... must reach the Coast Guard on or before September 15, 2010. ADDRESSES: You may submit comments... designed to protect sensitive environmental areas in the event of an oil or chemical spill in navigable... could be ordered to wait until the current has subsided and the boom removed to allow for safe...

  16. The gravitational potential energy regeneration system with closed-circuit of boom of hydraulic excavator

    Science.gov (United States)

    Chen, Mingdong; Zhao, Dingxuan

    2017-01-01

    Considering the disadvantage of higher throttling loss for the open-circuit hydrostatic transmission at present, a novel gravitational potential energy regeneration system (GPERS) of the boom of hydraulic excavator, namely the closed-circuit GPERS, is proposed in this paper. The closed-circuit GPERS is based on a closed-circuit hydrostatic transmission and adopts a hydraulic accumulator as main energy storage element fabricated in novel configuration to recover the entire gravitational potential energy of the boom of hydraulic excavator. The matching parameter and control system design are carried out for the proposed system, and the system is modeled based on its physical attributes. Simulation and experiments are performed to validate the employed mathematical models, and then, the velocity and the pressure performance of system are analyzed. It is observed that the closed-circuit GPERS shows better velocity control of the boom and response characteristics. After that, the average working efficiency of the closed-circuit GPERS of boom is estimated under different load conditions. The results indicate that the proposed system is highly effective and that the average working efficiency in different load conditions varied from 60% to 68.2% for the experiment platform.

  17. Summary of the 2008 NASA Fundamental Aeronautics Program Sonic Boom Prediction Workshop

    Science.gov (United States)

    Park, Michael A.; Aftosmis, Michael J.; Campbell, Richard L.; Carter, Melissa B.; Cliff, Susan; Nangert, Linda S.

    2013-01-01

    The Supersonics Project of the NASA Fundamental Aeronautics Program organized an internal sonic boom workshop to evaluate near- and mid-field sonic boom prediction capability at the Fundamental Aeronautics Annual Meeting in Atlanta, Georgia on October 8, 2008. Workshop participants computed sonic boom signatures for three non-lifting bodies and two lifting configurations. A cone-cylinder, parabolic, and quartic bodies of revolution comprised the non-lifting cases. The lifting configurations were a simple 69-degree delta wing body and a complete low-boom transport configuration designed during the High Speed Research Project in the 1990s with wing, body, tail, nacelle, and boundary layer diverter components. The AIRPLANE, Cart3D, FUN3D, and USM3D ow solvers were employed with the ANET signature propagation tool, output-based adaptation, and a priori adaptation based on freestream Mach number and angle of attack. Results were presented orally at the workshop. This article documents the workshop, results, and provides context on previously available and recently developed methods.

  18. Equity in an Educational Boom: Lessons from the Expansion and Marketisation of Tertiary Schooling in Poland

    Science.gov (United States)

    Herbst, Mikolaj; Rok, Jakub

    2014-01-01

    This article shows how the probability of enrolment in tertiary schools has evolved for different social groups in Poland during the period of the educational boom. It also analyses how the socio-economic status influences the choices between full-time and part-time studies (the latter being of relatively low quality), and the probability of…

  19. The Baby Boom Generation and the Labor Market in the Next Decade.

    Science.gov (United States)

    Russell, Louise B.

    1983-01-01

    Despite alarming predictions, the worklife expectations of America's "baby boom" generation may not be much different from those of other age cohorts. Besides demography, factors like technological change, industrial structures, and methods of management have a great influence on job availability. Employment trends remain difficult to…

  20. BABY BOOM (BBM) ChIP-seq in Arabidopsis somatic embryo tissue

    NARCIS (Netherlands)

    Horstman, A.; Muino Acuna, J.M.; Boutilier, K.A.

    2014-01-01

    After fertilization, a plant's life relies on progression through embryogenesis and maintenance of the stem cell niches from which all post-embryonic organs arise. BABY BOOM (BBM) and other members of the AINTEGUMENTA-LIKE (AIL)/PLETHORA (PLT) clade of the AP2-type transcription factor family play

  1. BABY BOOM target genes provide diverse entry points into cell proliferation and cell growth pathways

    NARCIS (Netherlands)

    Passarinho, P.A.; Ketelaar, M.J.; Xing, M.; Arkel, van J.; Maliepaard, C.A.; Weemen, W.M.J.; Joosen, R.V.L.; Lammers, M.; Herdies, L.; Boer, de B.; Geest, van der A.H.M.; Boutilier, K.A.

    2008-01-01

    Ectopic expression of the Brassica napus BABY BOOM (BBM) AP2/ERF transcription factor is sufficient to induce spontaneous cell proliferation leading primarily to somatic embryogenesis, but also to organogenesis and callus formation. We used DNA microarray analysis in combination with a

  2. The Baby Boom Generation and the Labor Market in the Next Decade.

    Science.gov (United States)

    Russell, Louise B.

    1983-01-01

    Despite alarming predictions, the worklife expectations of America's "baby boom" generation may not be much different from those of other age cohorts. Besides demography, factors like technological change, industrial structures, and methods of management have a great influence on job availability. Employment trends remain difficult to…

  3. Population Bulletin, Vol. 35, No. 1. America's Baby Boom Generation: The Fateful Bulge.

    Science.gov (United States)

    Bouvier, Leon F.

    During 1955 to 1964, nearly 42 million births occurred in the United States. This established a record unequaled to then and unlikely to soon be repeated. This bulletin explores the roots of the baby boom and its lasting impact on U.S. society; an impact accentuated by the unexpected interruption of a century-long fertility decline and the…

  4. Was Lates late? A null model for the Nile perch boom in Lake Victoria.

    Directory of Open Access Journals (Sweden)

    Andrea S Downing

    Full Text Available Nile perch (Lates niloticus suddenly invaded Lake Victoria between 1979 and 1987, 25 years after its introduction in the Ugandan side of the lake. Nile perch then replaced the native fish diversity and irreversibly altered the ecosystem and its role to lakeshore societies: it is now a prised export product that supports millions of livelihoods. The delay in the Nile perch boom led to a hunt for triggers of the sudden boom and generated several hypotheses regarding its growth at low abundances--all hypotheses having important implications for the management of Nile perch stocks. We use logistic growth as a parsimonious null model to predict when the Nile perch invasion should have been expected, given its growth rate, initial stock size and introduction year. We find the first exponential growth phase can explain the timing of the perch boom at the scale of Lake Victoria, suggesting that complex mechanisms are not necessary to explain the Nile perch invasion or its timing. However, the boom started in Kenya before Uganda, indicating perhaps that Allee effects act at smaller scales than that of the whole Lake. The Nile perch invasion of other lakes indicates that habitat differences may also have an effect on invasion success. Our results suggest there is probably no single management strategy applicable to the whole lake that would lead to both efficient and sustainable exploitation of its resources.

  5. BOOM: A Computer-Aided Engineering Tool for Exterior Ballistics of Smart Projectiles

    Science.gov (United States)

    2011-06-01

    run on PC, Unix, or Mac systems. 15. SUBJECT TERMS projectiles, trajectory , aeroballistics, flight mechanics, smart projectiles 16. SECURITY...system model are provided. The procedure for running BOOM is also outlined, with input data files described in the appendices. Example trajectories ...in equation 9, the aerodynamic forces on the projectile are split into standard steady (SA) and Magnus (MA) terms as follows

  6. Amsterdam Book Design: Irma Boom, Hansje van Halem, Lesley Moore = Amsterdamskij knižnyj dizajn

    NARCIS (Netherlands)

    M. Lommen

    2012-01-01

    Published on the occasion of the exhibition 'Amsterdam Book Design : Irma Boom, Hansje van Halem, Lesley Moore', from May 26th until June 17th 2012 in the creative platform Taiga Space, Saint Petersburg. In cooperation with Netherlands Institute Saint-Petersburg.

  7. An exploratory examination of medical gas booms versus traditional headwalls in intensive care unit design.

    Science.gov (United States)

    Pati, Debajyoti; Evans, Jennie; Waggener, Laurie; Harvey, Tom

    2008-01-01

    Should power, medical gases, and monitoring and communications systems be located in a headwall or a ceiling-mounted boom in intensive care unit (ICU) rooms? Often, only the financial costs could be determined for the options, whereas data regarding its potential influence on teamwork, safety, and efficiency are lacking. Hence, purchase decisions are more arbitrary than evidence based. This study simulated care delivery in settings with a traditional headwall and a ceiling boom. Observed were the way the following elements were managed and the extent either system affected flexibility, ergonomics, and teamwork: tubing for intravenous fluids, medical gases, and suction drainage; monitoring leads and equipment power cords; and the medical equipment itself. Simulation runs involving 6 scenarios were conducted with the voluntary participation of 2 physicians, 2 nurse practitioners, 2 respiratory therapists, and 4 registered nurses at a children's tertiary care center in December 2007. Analysis suggests that booms have an advantage over headwalls in case of high-acuity ICU patients and when procedures are performed inside patient rooms. However, in case of lower-acuity ICU patients, as well as when procedures are not typically conducted in the patient room, booms may not provide a proportionate level of advantage when compared with the additional cost involved in its procurement.

  8. Economic news through the magnifying glass : How the media cover economic boom and bust

    NARCIS (Netherlands)

    van Dalen, A.; de Vreese, C.; Albæk, E.

    2017-01-01

    One of the normative functions of economic news is surveillance, making monitorial citizens aware of significant economic developments. In this light, it is important to look at the way economic news covers periods of recession and economic boom. Previous studies have focused on how the media cover

  9. Equity in an Educational Boom: Lessons from the Expansion and Marketisation of Tertiary Schooling in Poland

    Science.gov (United States)

    Herbst, Mikolaj; Rok, Jakub

    2014-01-01

    This article shows how the probability of enrolment in tertiary schools has evolved for different social groups in Poland during the period of the educational boom. It also analyses how the socio-economic status influences the choices between full-time and part-time studies (the latter being of relatively low quality), and the probability of…

  10. Preliminary work about the reproduction of sonic boom signals for perception studies

    Science.gov (United States)

    Epain, N.; Herzog, P.; Rabau, G.; Friot, E.

    2006-05-01

    As part of a French research program, a sound restitution cabin was designed for investigating the annoyance of sonic boom signals. The first goal was to reproduce the boom spectrum and temporal waveform: this required linear generation of high pressure levels at infrasonic frequencies (110 SPL dB around 3 Hz), and response equalization over the full frequency range (1 Hz-20 kHz). At this stage the pressure inside the cabin was almost uniform around the listener, emulating an outdoor situation. A psychoacoustic study was then conducted which confirmed that the loudness (related to annoyance) of N-waves is roughly governed by the peak pressure, the rise/fall time, and the wave duration. A longer-term goal is to reproduce other aspects of an indoor situation including rattle noise, ground vibrations, and a more realistic spatial repartition of pressure. This latter point has been addressed through an Active Noise Control study aiming at monitoring the low-frequency acoustic pressure on a surface enclosing a listener. Frequency and time-domain numerical simulations of boom reproduction via ANC are given, including a sensitivity study of the coupling between a listener's head and the incident boom wave which combine into the effective sound-field to be reproduced.

  11. Interactions between Eurozone and US Booms and Busts: A Bayesian Panel Markov-switching VAR Model

    NARCIS (Netherlands)

    M. Billio (Monica); R. Casarin (Roberto); F. Ravazzolo (Francesco); H.K. van Dijk (Herman)

    2013-01-01

    markdownabstract__Abstract__ Interactions between the eurozone and US booms and busts and among major eurozone economies are analyzed by introducing a panel Markov-switching VAR model well suitable for a multi-country cyclical analysis. The model accommodates changes in low and high data frequencie

  12. 78 FR 39610 - Safety Zone; Big Bay Boom, San Diego Bay; San Diego, CA

    Science.gov (United States)

    2013-07-02

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Big Bay Boom, San Diego Bay; San Diego, CA... temporary safety zones upon the navigable waters of the San Diego Bay for the annual Port of San Diego... Sector San Diego, Coast Guard; telephone 619-278-7261, email d11marineeventssd@uscg.mil . If you have...

  13. 78 FR 29289 - Safety Zone; Big Bay Boom, San Diego Bay, San Diego, CA

    Science.gov (United States)

    2013-05-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Big Bay Boom, San Diego Bay, San Diego, CA... establish four temporary safety zones upon the navigable waters of San Diego ] Bay for the Port of San Diego... Management, U.S. Coast Guard Sector San Diego; telephone (619) 278-7261, email John.E.Bannon@uscg.mil . If...

  14. Numerical Simulation for sonic boom propagation through an Inhomogeneous atmosphere with winds

    Science.gov (United States)

    Yamamoto, Masafumi; Hashimoto, Atsushi; Takahashi, Takashi; Kamakura, Tomoo; Sakai, Takeharu

    2012-09-01

    Noise annoyance due to sonic boom is one of the serious problems for development of next-generation supersonic transport. To decrease this sonic boom noise, the design and analysis techniques are developed at Japan Aerospace eXploration Agency (JAXA). To predict the sonic boom on the ground accurately, we have developed a numerical code (Xnoise) using the augmented Burgers equation combined with the ray tracing. In this method, effects of nonlinearity, geometrical spreading, inhomogeneity of atmosphere, thermoviscous attenuation, molecular vibration relaxation and winds are taken into account. This method gives an estimation of the rise times of ground signatures without resorting to the weak shock theory and area balancing techniques. The nonlinear term is evaluated by the finite difference scheme in this method. In ray-path calculation, an explicit updating methodology is adopted. The augmented Burgers equation is numerically solved by using the operator split method entirely in the time domain. As for the effects of nonlinearity, geometrical spreading, and atmospheric inhomogeneity, the result obtained with the augmented Burgers equation agrees well with that obtained with the waveform parameter method (Thomas' method). For the effects of absorption and dispersion, the calculation based on the augmented Burgers equation is verified by comparing with a detailed one-dimensional CFD analysis. Moreover, we show calculations which account the effect of winds on the propagation of a sonic boom. The validation of model is a future work.

  15. Self-healing properties of carbon nanotube filled natural rubber/bromobutyl rubber blends

    Directory of Open Access Journals (Sweden)

    H. H. Le

    2017-03-01

    Full Text Available In the present work, the development and characterization of an intrinsically self-healable material based on butyl imidazole modified bromobutyl rubber (BIIR/natural rubber (NR blends, which are filled with carbon nanotubes (CNTs are reported. It was found that the addition of CNTs and the blending with NR significantly enhance the tensile strength of the BIIR composites. The use of butyl imidazole as physical cross-linker for the BIIR phase provides the blend composites the non-covalent bondings, which are responsible for their self-healing properties. Owing to the increase of the viscosity of the BIIR phase upon its physical crosslinking the island-matrix morphology of the blend changes over to a co-continuous structure. The preferential wetting of the CNT surface by the low-loading NR phase in the NR/BIIR blends can be explained by the good rubber-filler interaction between the linked phospholipids of the NR molecules and the π-electrons of the CNT surface. As a result, the favored localization of the CNTs in the NR phase strongly improves the electrical properties of the blends according to the double percolation theory. On the other hand it does not deteriorate the self-healing of the BIIR phase. The high electrical conductivity provides us a possibility to heat the blend by application of an electrical voltage in order to accelerate the self-healing process.

  16. 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.

  17. 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

  18. Interactive Inverse Design Optimization of Fuselage Shape for Low-Boom Supersonic Concepts

    Science.gov (United States)

    Li, Wu; Shields, Elwood; Le, Daniel

    2008-01-01

    This paper introduces a tool called BOSS (Boom Optimization using Smoothest Shape modifications). BOSS utilizes interactive inverse design optimization to develop a fuselage shape that yields a low-boom aircraft configuration. A fundamental reason for developing BOSS is the need to generate feasible low-boom conceptual designs that are appropriate for further refinement using computational fluid dynamics (CFD) based preliminary design methods. BOSS was not developed to provide a numerical solution to the inverse design problem. Instead, BOSS was intended to help designers find the right configuration among an infinite number of possible configurations that are equally good using any numerical figure of merit. BOSS uses the smoothest shape modification strategy for modifying the fuselage radius distribution at 100 or more longitudinal locations to find a smooth fuselage shape that reduces the discrepancies between the design and target equivalent area distributions over any specified range of effective distance. For any given supersonic concept (with wing, fuselage, nacelles, tails, and/or canards), a designer can examine the differences between the design and target equivalent areas, decide which part of the design equivalent area curve needs to be modified, choose a desirable rate for the reduction of the discrepancies over the specified range, and select a parameter for smoothness control of the fuselage shape. BOSS will then generate a fuselage shape based on the designer's inputs in a matter of seconds. Using BOSS, within a few hours, a designer can either generate a realistic fuselage shape that yields a supersonic configuration with a low-boom ground signature or quickly eliminate any configuration that cannot achieve low-boom characteristics with fuselage shaping alone. A conceptual design case study is documented to demonstrate how BOSS can be used to develop a low-boom supersonic concept from a low-drag supersonic concept. The paper also contains a study

  19. Unraveling the mystery of natural rubber biosythesis part I: investigation of the composition and growth of in vitro natural rubber using high resolution size exclusion chromatography

    Science.gov (United States)

    Monitoring the growth of in vitro natural rubberwas accomplished by high resolution size exclusion chromatography, SEC.Washed rubber particles isolated from H. brasiliensis latex, containing the rubber transferase enzyme, were used to catalyze the polymerization of synthetic isopentenyl pyrophosphat...

  20. Allergenic proteins of natural rubber latex.

    Science.gov (United States)

    Yeang, H Y; Arif, Siti Arija M; Yusof, Faridah; Sunderasan, E

    2002-05-01

    As the living cytoplasm of laticiferous cells, Hevea brasiliensis latex is a rich blend of organic substances that include a mélange of proteins. A small number of these proteins have given rise to the problem of latex allergy. The salient characteristics of H. brasiliensis latex allergens that are recognized by the International Union of Immunological Societies (IUIS) are reviewed. These are the proteins associated with the rubber particles, the cytosolic C-serum proteins and the B-serum proteins that originate mainly from the lutoids. Procedures for the isolation and purification of latex allergens are discussed, from latex collection in the field to various preparative approaches adopted in the laboratory. As interest in recombinant latex allergens increases, there is a need to validate recombinant proteins to ascertain equivalence with their native counterparts when used in immunological studies, diagnostics, and immunotherapy.

  1. Cellulose nanocrystal reinforced oxidized natural rubber nanocomposites.

    Science.gov (United States)

    Mariano, Marcos; El Kissi, Nadia; Dufresne, Alain

    2016-02-10

    Natural rubber (NR) latex particles were oxidized using KMnO4 as oxidant to promote the insertion of hydroxyl groups in the surface polyisoprene chains. Different degrees of oxidation were investigated. Both unoxidized and oxidized NR (ONR) latex were used to prepare nanocomposite films reinforced with cellulose nanocrystals (CNCs) by casting/evaporation. The oxidation of NR was carried out to promote chemical interactions between the hydroxyl groups of ONR with those of CNCs through hydrogen bonding. The effect of the degree of oxidation of the NR latex on the rheological behavior of CNC/NR and CNC/ONR suspensions, as well as on the mechanical, swelling and thermal properties of ensuing nanocomposites was investigated. Improved properties were observed for intermediate degrees of oxidation but they were found to degrade for higher oxidation levels.

  2. Silicone-Rubber Microvalves Actuated by Paraffin

    Science.gov (United States)

    Svelha, Danielle; Feldman, Sabrina; Barsic, David

    2004-01-01

    Microvalves containing silicone-rubber seals actuated by heating and cooling of paraffin have been proposed for development as integral components of microfluidic systems. In comparison with other microvalves actuated by various means (electrostatic, electromagnetic, piezoelectric, pneumatic, and others), the proposed valves (1) would contain simpler structures that could be fabricated at lower cost and (2) could be actuated by simpler (and thus less expensive) control systems. Each valve according to the proposal would include a flow channel bounded on one side by a flat surface and on the other side by a curved surface defined by an arched-cross-section, elastic seal made of silicone rubber [polydimethylsilane (PDMS)]. The seal would be sized and shaped so that the elasticity of the PDMS would hold the channel open except when the seal was pressed down onto the flat surface to close the channel. The principle of actuation would exploit the fact that upon melting or freezing, the volume of a typical paraffin increases or decreases, respectively, by about 15 percent. In a valve according to the proposal, the seal face opposite that of the channel would be in contact with a piston-like plug of paraffin. In the case of a valve designed to be normally open at ambient temperature, one would use a paraffin having a melting temperature above ambient. The seal would be pushed against the flat surface to close the channel by heating the paraffin above its melting temperature. In the case of a valve designed to be normally closed at ambient temperature, one would use a paraffin having a melting temperature below ambient. The seal would be allowed to spring away from the flat surface to open the channel by cooling the paraffin below its melting temperature. The availability of paraffins that have melting temperatures from 70 to +80 C should make it possible to develop a variety of normally closed and normally open valves. The figure depicts examples of prototype normally

  3. Polybenzoxazole-filled nitrile butadiene rubber compositions

    Science.gov (United States)

    Gajiwala, Himansu M. (Inventor); Guillot, David G. (Inventor)

    2008-01-01

    An insulation composition that comprises at least one nitrile butadiene rubber (NBR) having an acrylonitrile content that ranges from approximately 26% by weight to approximately 35% by weight and polybenzoxazole (PBO) fibers. The NBR may be a copolymer of acrylonitrile and butadiene and may be present in the insulation composition in a range of from approximately 45% by weight to approximately 56% by weight of a total weight of the insulation composition. The PBO fibers may be present in a range of from approximately 3% by weight to approximately 10% by weight of a total weight of the insulation composition. A rocket motor including the insulation composition and a method of insulating a rocket motor are also disclosed.

  4. Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites.

    Science.gov (United States)

    Chen, Yukun; Zhang, Yuanbing; Xu, Chuanhui; Cao, Xiaodong

    2015-10-05

    Research on foamed nitrile rubber (NBR)/cellulose nanocrystals (CNs) nanocomposites is rarely found in the literatures. In this paper, CNs suspension and NBR latex was mixed to prepared the foamed NBR/CNs nanocomposites. We found that the CNs mainly located in the cell walls, effectively reinforcing the foamed NBR. The strong interaction between the CNs and NBR matrix restricted the mobility of NBR chains surrounding the CNs, hence increasing the crosslink density of the NBR matrix. CNs exhibited excellent reinforcement on the foamed NBR: a remarkable increase nearly 76% in the tensile strength of the foamed nanocomposites was achieved with a load of only 15 phr CNs. Enhanced mechanical properties make the foamed NBR/CNs nanocomposites a promising damping material for industrial applications with a potential to reduce the petroleum consumption.

  5. HYDROPHOBICITY OF CONTAMINATED SILICONE RUBBER SURFACES

    Institute of Scientific and Technical Information of China (English)

    Zhi-min Zheng; Cai-hong Xu; Jian Jiang; Chang-yu Ren; Wei Gao; Ze-min Xie

    2002-01-01

    Silicone rubber (SIR) shows superior performance when used outdoors, but its surface can be transformed frominherently hydrophobic to hydrophilic by the adsorption of contaminants. Al(OH)3, Al2O3, quartz powder and active carbonwere selected as authentic contaminants. Hydrophobicity of the surface was determined using contact angle measurement.The results indicate that the adsorbability of the contaminants can strongly affect the hydrophobicity of contaminated SIRsurface. The increasing rate of contact angle of specimens contaminated by Al(OH)3 was much faster than that by Al2O3 andquartz due to the adsorption of migrated low molecular weight (LMW) polydimethylsiloxanes. Specimens contaminated byactive carbon could achieve surface hydrophobicity within 15 min because active carbon has high adsorbability. Surfaces ofcontaminated ultrapure SIR, polytetrafluoroethylene (PTFE) and glass remain hydrophilic because they contain no mobileLMW components. The addition of oligomeric polydimethylsiloxanes has little effect on the hydrophobicity of contaminantscovered on SIR surface.

  6. Mach Cutoff Analysis and Results from NASA's Farfield Investigation of No-Boom Thresholds

    Science.gov (United States)

    Cliatt, Larry J., II; Hill, Michael A.; Haering, Edward A., Jr.

    2016-01-01

    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 partnership with other industry organizations and academia, conducted a flight research experiment to analyze acoustic propagation in the Mach cutoff shadow zone. The effort was conducted in the fall of 2012 and named the Farfield Investigation of No-boom Thresholds (FaINT). The test helped to build a dataset that will go toward further understanding of the unique acoustic propagation characteristics below Mach cutoff altitude. FaINT was able to correlate sonic boom noise levels measured below cutoff altitude with precise airplane flight conditions, potentially increasing the accuracy over previous studies. A NASA F-18B airplane made supersonic passes such that its Mach cutoff caustic would be at varying distances above a linear 60-microphone, 7375-ft (2247.9 m) long array. A TG-14 motor glider equipped with a microphone on its wing-tip also attempted to capture the same sonic boom waves above ground, but below the Mach cutoff altitude. This paper identified an appropriate metric for sonic boom waveforms in the Mach cutoff shadow zone called Perceived Sound Exposure Level; derived an empirical relationship between Mach cutoff flight conditions and noise levels in the shadow zone; validated a safe cutoff altitude theory presented by previous studies; analyzed the sensitivity of flight below Mach cutoff to unsteady atmospheric conditions and realistic aircraft perturbations; and demonstrated the ability to record sonic boom measurements over 5000 ft (1524.0 m) above ground level, but below Mach cutoff altitude.

  7. minimum variance estimation of yield parameters of rubber tree with ...

    African Journals Online (AJOL)

    2013-03-01

    Mar 1, 2013 ... STAMP, an OxMetric modular software system for time series analysis, was used to estimate the yield ... derlying regression techniques. .... Kalman Filter Minimum Variance Estimation of Rubber Tree Yield Parameters. 83.

  8. Thermo-Mechanical Analyses of Dynamically Loaded Rubber Cylinders

    Science.gov (United States)

    Johnson, Arthur R.; Chen, Tzi-Kang

    2002-01-01

    Thick rubber components are employed by the Army to carry large loads. In tanks, rubber covers road wheels and track systems to protect roadways. It is difficult for design engineers to simulate the details of the hysteretic heating for large strain viscoelastic deformations. In this study, an approximation to the viscoelastic energy dissipated per unit time is investigated for use in estimating mechanically induced viscoelastic heating. Coupled thermo-mechanical simulations of large cyclic deformations of rubber cylinders are presented. The cylinders are first compressed axially and then cyclically loaded about the compressed state. Details of the algorithm and some computational issues are discussed. The coupled analyses are conducted for tall and short rubber cylinders both with and without imbedded metal disks.

  9. Metal Rubber Sensor Appliquis for Rotor Blade Air Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thin film Metal RubberTM sensor appliqus have the potential to reduce the time, complexity and cost of measuring air flow-induced skin friction during the...

  10. Prevention of Fungal Growth on Rubber Earpads of Telecommunication Equipments

    Directory of Open Access Journals (Sweden)

    B. P. Uniyal

    1971-01-01

    Full Text Available This paper recommends an addition of 100% zinc oxide to the rubber composition during its manufacture to effectively prevent fungal growth on the earpads without producing any adverse on its materials/performance or the user.

  11. Super Lightweight, Metal Rubber Fabric for Extreme Space Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NanoSonic has fabricated revolutionary nanostructured, yet macroscale, multifunctional Metal RubberTM films via layer-by-layer, molecular self-assembly, which...

  12. Radiation Resistant, Reconfigurable, Shape Memory Metal Rubber Space Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NanoSonic has demonstrated that Shape Memory Metal RubberTM (SM-MR) adaptive skins exhibit reconfigurable and durable RF properties. It is hypothesized that such...

  13. Sand - rubber mixtures submitted to isotropic loading: a minimal model

    Science.gov (United States)

    Platzer, Auriane; Rouhanifar, Salman; Richard, Patrick; Cazacliu, Bogdan; Ibraim, Erdin

    2017-06-01

    The volume of scrap tyres, an undesired urban waste, is increasing rapidly in every country. Mixing sand and rubber particles as a lightweight backfill is one of the possible alternatives to avoid stockpiling them in the environment. This paper presents a minimal model aiming to capture the evolution of the void ratio of sand-rubber mixtures undergoing an isotropic compression loading. It is based on the idea that, submitted to a pressure, the rubber chips deform and partially fill the porous space of the system, leading to a decrease of the void ratio with increasing pressure. Our simple approach is capable of reproducing experimental data for two types of sand (a rounded one and a sub-angular one) and up to mixtures composed of 50% of rubber.

  14. Ciprofloxacin Release Using Natural Rubber Latex Membranes as Carrier

    National Research Council Canada - National Science Library

    Dias Murbach, Heitor; Jaques Ogawa, Guilherme; Azevedo Borges, Felipe; Romeiro Miranda, Matheus Carlos; Lopes, Rute; Roberto de Barros, Natan; Guedes Mazalli, Alexandre Vinicius; Gonçalves da Silva, Rosângela; Ferreira Cinman, José Luiz; de Camargo Drago, Bruno; Donizetti Herculano, Rondinelli

    2014-01-01

      Natural rubber latex (NRL) from Hevea brasiliensis is easily manipulated, low cost, is of can stimulate natural angiogenesis and cellular adhesion, is a biocompatible, material and presents high mechanical resistance. Ciprofloxacin (CIP...

  15. Radiation Vulcanised Natural Rubber Latex: safer than conventionally processed latex?

    NARCIS (Netherlands)

    Geertsma RE; Orzechowski TJH; Jonker M; Dorpema JW; Asten JAAM van; LGM

    1996-01-01

    Door middel van cytotoxiciteitstesten is aangetoond dat RVNRL (straling-gevulcaniseerde natuurlijke latex rubber) materialen aanzienlijk minder cytotoxisch zijn dan zwavel-gevulcaniseerde materialen. Dit is een sterke aanwijzing dat een deel van de allergieproblemen, namelijk de zogeheten Type

  16. 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.

  17. Multifunctional, Nanostructured Metal Rubber Protective Films for Space Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NanoSonic has developed revolutionary nanostructured, yet macroscale, multifunctional Metal RubberTM films. In support of NASA's Vision for Space Exploration, low...

  18. Lightweight Metal RubberTM Sensors and Interconnects Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this NASA Phase II program is to develop and increase the Technology Readiness Level of multifunctional Metal RubberTM (MRTM) materials that can be...

  19. Advanced Metal Rubber Sensors for Hypersonic Decelerator Entry Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NanoSonic proposes to design and develop light-weight, low-modulus, and durable Metal Rubber™ sensors for aeroelastic analysis of Hypersonic Decelerator Entry...

  20. Strength of Concrete Containing Rubber Particle as Partial Cement Replacement

    Directory of Open Access Journals (Sweden)

    Abdullah Siti Radziah

    2016-01-01

    Full Text Available Uncontrolled issues of disposal waste tire rubber create huge environmental impact and health hazards. An alternative viable solution to minimize these problems is by utilizing the waste rubber tires in construction materials, which in turn can reduce the use of natural resources and eventually lessen the cost of construction. This paper mainly focuses on the use of waste rubber tires particles in concrete with different set of composition ranging from 3 to 12% of cement replacement. Concrete cubes size of 150mm x 150mm x 150mm were prepared for compressive strength test, and concrete cylinders size of 150m x 300mm were prepared for splitting tensile test. The result shows that the compressive and split tensile strength of concrete with rubber as cement replacements is 6-21% lower than the normal concrete.

  1. Tribological Aspect of Rubber Based Parts used in Engineering

    Directory of Open Access Journals (Sweden)

    D. Stamenković

    2014-03-01

    Full Text Available In most of the cases, the friction is considered as a negative side-effect concerning energy loss following every process of the power transmission. However, the friction has significant positive side effects, because it is an indispensable prerequisite for the movement of people, machines, transportation means and others. Efficiency of these movements mostly depends on the friction between rubber and different materials such as metals, concrete, earth, wood, plastic, etc. Certain standards relating to measurement and determination of the friction characteristics of rubber were established. However considering that tribology of the rubber is very complex problem, numerous studies around the world are conducted. This paper gives an overview of some of the existing standards and conducted researches in this area. The paper also provides an overview of theoretical and experimental studies of friction the rubber and the other materials, which are done at Faculty of Mechanical Engineering in Niš.

  2. Altered levels of the Taraxacum kok-saghyz (Russian dandelion) small rubber particle protein, TkSRPP3, result in qualitative and quantitative changes in rubber metabolism.

    Science.gov (United States)

    Collins-Silva, Jillian; Nural, Aise Taban; Skaggs, Amanda; Scott, Deborah; Hathwaik, Upul; Woolsey, Rebekah; Schegg, Kathleen; McMahan, Colleen; Whalen, Maureen; Cornish, Katrina; Shintani, David

    2012-07-01

    Several proteins have been identified and implicated in natural rubber biosynthesis, one of which, the small rubber particle protein (SRPP), was originally identified in Hevea brasiliensis as an abundant protein associated with cytosolic vesicles known as rubber particles. While previous in vitro studies suggest that SRPP plays a role in rubber biosynthesis, in vivo evidence is lacking to support this hypothesis. To address this issue, a transgene approach was taken in Taraxacum kok-saghyz (Russian dandelion or Tk) to determine if altered SRPP levels would influence rubber biosynthesis. Three dandelion SRPPs were found to be highly abundant on dandelion rubber particles. The most abundant particle associated SRPP, TkSRPP3, showed temporal and spatial patterns of expression consistent with patterns of natural rubber accumulation in dandelion. To confirm its role in rubber biosynthesis, TkSRPP3 expression was altered in Russian dandelion using over-expression and RNAi methods. While TkSRPP3 over-expressing lines had slightly higher levels of rubber in their roots, relative to the control, TkSRPP3 RNAi lines showed significant decreases in root rubber content and produced dramatically lower molecular weight rubber than the control line. Not only do results here provide in vivo evidence of TkSRPP proteins affecting the amount of rubber in dandelion root, but they also suggest a function in regulating the molecular weight of the cis-1, 4-polyisoprene polymer.

  3. 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.

  4. Thermomechanical analysis of Natural Rubber behaviour stressed at room temperature.

    OpenAIRE

    Chrysochoos A.; Wattrisse B.; Muracciole J.M.; Caborgan R.

    2010-01-01

    Owing to their high molecular mobility, stressed rubber chains can easily change their conformations and get orientated. This phenomena leads to so high reversible draw ratio that this behaviour is called rubber elasticity [1-3]. The analogy with ideal gases leads to an internal energy independent of elongation, the stress being attributed to a so-called configuration entropy. However, this analysis cannot take thermal expansion into account and moreover prohibits predicting standard th...

  5. Dalian Rubber & Plastics Hong Kong Company Acquired a Rubber Machinery Enterprise of the Czech Republic%Dalian Rubber & Plastics Hong Kong Company Acquired a Rubber Machinery Enterprise of the Czech Republic

    Institute of Scientific and Technical Information of China (English)

    FengPei

    2011-01-01

    To further widen the international market, improve the technical content of products and boost the profitability of the enterprise, Dalian Rubber & Plastics Hong Kong Company, jointly invested and established by Dalian State-owned Assets Investment and Management Group Co., Ltd. and Dalian Rubber & Plastics Machinery Co., Ltd., plans to invest about EUR 12.50 million to acquire 90% stock fight of Buzuluk Company of the Czech Republic.

  6. Serbia: A new process for waste rubber and plastic recycling

    Directory of Open Access Journals (Sweden)

    Ozren Ocic

    2010-02-01

    Full Text Available This paper intends to describe a new technological process for waste rubber and plastic recycling up to the commercial components in safe environmental friendly way. Researches and all relevant technical-technological data related to this process are checked at constructed pilot plant. The future construction of these units for waste rubber and plastic recycling will allow interested parties to achieve the environmental effectiveness and economic efficiency.

  7. Studies on Hydrogenation of Liquid Natural Rubber Using Diimide

    Directory of Open Access Journals (Sweden)

    Nur Hanis Adila Azhar

    2015-01-01

    Full Text Available Liquid natural rubber (LNR is a depolymerized natural rubber (NR which consists of shorter polymeric chains and lower molecular weight (Mw90% was achieved by manipulating the reaction parameters such as sources of diimide, TSH concentration, solvent, and reaction time. The optimum condition was 3 : 1 weight ratio of TSH/LNR in o-xylene at 130°C in 4-hour reaction period.

  8. The toughening mechanism of rubber particles in polypropylene composite

    Science.gov (United States)

    Shi, L.; Xiao, J. M.

    2017-01-01

    Filling polypropylene materials with rubber particles can effectively increase the toughness of PP material and improve its cushioning properties. In this paper, we used the two kinds of method of the finite element analysis and experiment to study the rubber particles toughening mechanism, got the deformation process of particles when polypropylene material compressed and the yield stress of polypropylene after compression with particles filled or not.

  9. Characterization of Rubbers from Spherical Punch - Plate Indentation Tests

    Directory of Open Access Journals (Sweden)

    Florina Carmen Ciornei

    2016-12-01

    Full Text Available Rubber plates with different compositions and hardness were tested by continuous indentation, using a spherical punch and hysteretic phenomenon was evidenced. The experimental data interpolation with polynomial functions is accurate and permits estimation of the lost work during loading cycles. The interpolation by power law functions is more convenient by using less parameters and having a form accepted in literature. From the rubbers tested, two were considered to present good damping properties.

  10. Actitudes y prácticas frente a la sexualidad de los homosexuales

    OpenAIRE

    Patricia Vélez-Laguado; Yessenia Rojas-Dodino; Andrea Marcela Mogollón-González

    2015-01-01

    Objetivo: evaluar las actitudes y prácticas frente a la sexualidad de la comunidad de lesbianas, gais, bisexuales, transexuales, intersexuales y como estas influyen en su salud sexual y reproductiva. Materiales y Métodos: estudio cuantitativo, descriptivo de corte transversal. La población estudio fueron 335 homosexuales pertenecientes a una fundación X, la muestra correspondió a 180, a quienes se aplico el instrumento Actitudes y Prácticas frente a la Sexualidad de los Homosexuales. Los cri...

  11. Perfil dos pais frente ao atendimento odontológico na primeira infância

    OpenAIRE

    Renata Mesquita e OLIVEIRA

    2007-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Odontologia. O presente estudo objetivou conhecer a perfil dos pais frente à saúde bucal de seus filhos, avaliando sua percepção frente ao atendimento odontológico na primeira infância e conhecendo a opinião dos mesmos quanto às técnicas de manejo de comportamento utilizadas em bebês. Foi realizado um estudo descritivo transversal. A amostra foi composta por 40 pais d...

  12. Vacuna frente a infestaciones provocadas por artrópodos hematófagos

    OpenAIRE

    Fuente García, José de la; Villar, Margarita; Prudencio,Carlos Roberto; Pérez de Lastra, José Manuel

    2012-01-01

    La presente invención describe una vacuna frente a infestaciones provocadas por artrópodos hematófagos preferentemente garrapatas, mosquitos, flebótomos, ácaros rojos de las gallinas, pulgas, piojos, piojos de mar, etc. Así mismo, se protege un péptido capaz de inducir una respuesta inmune protectora y de reacción cruzada frente a una infestación provocada por artrópodos hematófagos, un polinucleótido, un vector de expresión, una célula hospedadora, un animal no hum...

  13. Vacuna frente a infestaciones provocadas por artrópodos hematófagos

    OpenAIRE

    Fuente García, José de la; Villar, Margarita; Prudencio,Carlos Roberto; Pérez de Lastra, José Manuel

    2012-01-01

    [ES] La presente invención describe una vacuna frente a infestaciones provocadas por artrópodos hematófagos preferentemente garrapatas, mosquitos, flebótomos, ácaros rojos de las gallinas, pulgas, piojos, piojos de mar, etc. Así mismo, se protege un péptido capaz de inducir una respuesta inmune protectora y de reacción cruzada frente a una infestación provocada por artrópodos hematófagos, un polinucleótido, un vector de expresión, una célula hospedadora, un animal no humano, un anticuerpo, y ...

  14. Comportamiento frente a la oxidación de aleaciones de titanio alfa + beta

    OpenAIRE

    Vicente Escuder, Ángel; Schalht, A.; Amigó Mata, Angèlica; Amigó Borrás, Vicente

    2014-01-01

    Las aleaciones +, presentan excelentes propiedades mecánicas y frente a la corrosión lo que las hace excelentes candidatas para su aplicación en la industria química y aeronáutica, pero es importante mejorar su comportamiento frente a elevadas temperaturas, sobre todo su oxidación a esas temperaturas. En el presente trabajo se estudia la obtención de aleaciones + del tipo Ti-3%at. X (Nb, Mo, Ta) por vía pulvimetalúrgica a partir de mezcla elemental de polvos...

  15. Criteria for asphalt-rubber concrete in civil airport pavements: Mixture design

    Science.gov (United States)

    Roberts, F. L.; Lytton, R. L.; Hoyt, D.

    1986-07-01

    A mixture design procedure is developed to allow the use of asphalt-rubber binders in concrete for flexible airport pavement. The asphalt-rubber is produced by reacting asphalt with ground, scrap tire rubber to produce the binder for the asphalt-rubber concrete. Procedures for laboratory preparation of alsphalt-rubber binders using an equipment setup that was found by researchers to produce laboratory binders with similar properties to field processes are included. The rubber-asphalt concrete mixture design procedure includes adjustments to the aggregate gradation to permit space for the rubber particles in the asphalt-rubber binder as well as suggested mixing and compaction temperatures, and compaction efforts. While the procedure was used in the laboratory to successfully produce asphalt-rubber concrete mixtures, it should be evaluated in the field to ensure that consistent results can be achieved in a production environment.

  16. 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).

  17. Dielectric Properties of Compatibilised EPDM/Silicone rubber Nanocomposites

    Directory of Open Access Journals (Sweden)

    Vijayalekshmi Vijayakumar

    2017-06-01

    Full Text Available EPDM/Silicone rubber nanocomposites are prepared by incorporating various phr of organically modified montmorillonite (OMMT nanoclay onto compatibilised and uncompatibilised EPDM/Silicone rubber blends using two roll mill. Compatibilisation of EPDM and Silicone rubber blend is achieved through insitu grafting of silane onto EPDM during mixing of rubbers. Effect of OMMT content and compatibilisation of blend system on electrical, mechanical and thermal properties of the nanocomposites are investigated. The results obtained for various properties indicate that the compatibilised EPDM/Silicone rubber nanocomposites have improved dielectric, mechanical and thermal properties compared to that of uncompatibilised blend nanocomposites. It is observed that, the addition of OMMT upto 5 phr onto both compatibilised and uncompatibilised blends of EPDM/Silicone offers significant improvement in the above mentioned properties. Increasing content of OMMT onto the blends cause marked enhancement in thermal stability of the nanocomposties. Transmission electron micrographs shows the compatibility between EPDM and silicone rubbers in the blend and the exfoliation of OMMT layers in the matrix phase. The present work reveals that the compatibilised EPDM/ Silicone/ OMMT nanocomposite can be a better candidate for high voltage electrical insulation due to its enhanced dielectric, mechanical and themal characteristics.

  18. Effects of rubberized flooring on Asian elephant behavior in captivity.

    Science.gov (United States)

    Meller, Camie L; Croney, Candace C; Shepherdson, David

    2007-01-01

    Six Asian elephants at the Oregon Zoo were observed to determine the effects of a poured rubber flooring substrate on captive Asian elephant behavior. Room utilization also was evaluated in seven rooms used for indoor housing, including Front and Back observation areas. Data were collected in three phases. Phase I (Baseline Phase) examined elephant behavior on old concrete floors. In Phase II (Choice Phase), elephant behavior was observed in the Back observation area where room sizes were comparable and when a choice of flooring substrates was available. Phase III (Final Phase) examined elephant behavior when all rooms in both observation areas, Front and Back, were converted to rubberized flooring. Room use in both observation areas remained stable throughout the study, suggesting that flooring substrate did not affect room use choice. However, there was a clear pattern of decreased discomfort behaviors on the new rubber flooring. Normal locomotion as well as stereotypic locomotion increased on the new rubber flooring. In addition, resting behavior changed to more closely reflect the resting behavior of wild elephants, which typically sleep standing up, and spend very little time in lateral recumbence. Overall, these findings suggest that the rubber flooring may have provided a more comfortable surface for locomotion as well as standing resting behavior. It is suggested that poured rubber flooring may be a beneficial addition to similar animal facilities. Zoo Biol 0:1-11, 2007. (c) 2007 Wiley-Liss, Inc.

  19. [Allergic contact dermatitis to synthetic rubber, neoprene in compression stockings].

    Science.gov (United States)

    Mizuno, Ju; In-Nami, Hiroshi

    2011-01-01

    Compression stockings are used for patients under general anesthesia to prevent occurrence of deep venous thrombosis. We report a case of allergic contact dermatitis to synthetic rubber, neoprene in compression stockings. A 53-year-old house wife had a history of sensitivity like skin eruption and disstasis to rubber products such as rubber band. Left nephrectomy for rupture of renal angiomyolipoma was scheduled under general and epidural anesthesia. Further examination for gum allergy was not performed before the operation, although latex allergy was suspected. The operation was performed uneventfully under latex-safe environment in the operating room under guideline for latex allergy. Postoperatively, ringed edematous erythema and wheal occurred in her bilateral thighs compressed with the upper part of compression stockings. The skin symptoms continued for more than four days. After disappearance of the skin symptoms, she was discharged from the hospital on the ninth day after the operation. Synthetic rubber, neoprene, in the upper part of compression stockings to prevent slipping down might cause allergic contact dermatitis. We should take care of occurrence of allergic contact dermatitis to synthetic rubber, neoprene in compression stockings in patients with rubber allergy.

  20. COORDINATION CROSSLINKING OF NITRILE RUBBER FILLED WITH COPPER SULFATE PARTICLES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    By incorporating copper sulfate (CuSO4) particles into acrylonitrile butadiene rubber (NBR) followed by heat pressing.a novel vulcanization method is developed in rubber through the formation of coordination crosslinking.This method totally differs from traditional covalent or non-covalent vulcanization approaches of rubber.No other vulcanizing agent or additional additive is involved in this process.By analyzing the results of DMA,XPS and FT-IR,it is found that the crosslinking of CuSO4 particles filled NBR was induced by in situ coordination between nitrogen atoms of nitrile groups (-CN) and copper ions (Cu2+) from CuSO4.SEM and EDX results revealed the generation of a core (CuSO4 solid particle) shell (adherent NBR) structure,which leads to a result that the crosslinked rubber has excellent mechanical properties.Moreover,poly (vinyl chloride)(PVC) and liquid acrylonitrile-butadiene rubber (LNBR) were used as mobilizer to improve the coordination crosslinking of CuSO4/NBR.The addition of PVC or LNBR could lead to higher crosslink density and better mechanical properties of coordination vulcanization.In addition,crystal water in CuSO4 played a positive role to coordination crosslinking of rubber because it decreased the metal point of CuSO4 and promoted the metal ionization.

  1. Effect of rubber dam on mercury exposure during amalgam removal.

    Science.gov (United States)

    Kremers, L; Halbach, S; Willruth, H; Mehl, A; Welzl, G; Wack, F X; Hickel, R; Greim, H

    1999-06-01

    It was the aim of this investigation to treat 20 volunteers with maximally 5 amalgam fillings by the same comprehensive protocol in which all removals with (n = 8) and without (n = 12) rubber dam had been performed within a few months. Nine amalgam-related parameters indicated a close matching of both groups before removal. In the group without rubber dam, mercury (Hg) levels in plasma increased significantly above preremoval values at days 1 and 3 after removal; they decreased significantly below preremoval values at day 30 in the rubber-dam group and at day 100 in both groups. Excretion rates did not increase significantly in either group, but decreased significantly at day 100 in the protected group. Peak plasma-Hg was 0.6 ng/mL on average at day one and decreased with halftimes of 3 and 43 d in subjects protected by rubber dam. The results indicated that concentrations of total mercury in plasma responded rapidly to changes in the amalgam status and reflected the actual absorption most reliably. Notably, plasma-Hg levels were sensitive enough to detect a transient attenuation of the additional exposure by using rubber dam during the removal of only a few fillings. However, being small in magnitude and lasting 100 d at best, the rubber-dam effect had minor toxicological relevance.

  2. Genotoxic risk in rubber manufacturing industry: a systematic review.

    Science.gov (United States)

    Bolognesi, Claudia; Moretto, Angelo

    2014-10-15

    A large body of evidence from epidemiological studies among workers employed in the rubber manufacturing industry has indicated a significant excess cancer risk in a variety of sites. The International Agency for Research on Cancer has recently classified the "Occupational exposures in the rubber-manufacturing industry" as carcinogenic to humans (Group 1). A genotoxic mechanism for the increased cancer risk was suggested on the basis of the evidence from the scientific literature. Exposure assessment studies have shown that workers in the rubber manufacturing industry may be exposed to different airborne carcinogenic and/or genotoxic chemicals, such as certain aromatic amines, polycyclic aromatic hydrocarbons, N-nitrosamines, although the available information does not allow to establish a causal association of cancer or genotoxic risk with particular substances/classes of chemicals or specific jobs. The aim of this paper is to critically evaluate, by conducting a systematic review, the available biomonitoring studies using genotoxicity biomarkers in rubber manufacturing industry. This systematic review suggests that a genotoxic hazard may still be present in certain rubber manufacturing industries. A quantitative risk assessment needs further studies addressing the different, processes and chemicals in the rubber manufacturing industries.

  3. DAMAGE OF SILICONE RUBBER INDUCED BY PROTON IRRADIATION

    Institute of Scientific and Technical Information of China (English)

    Li-xin Zhang; Shi-qin Yang; Shi-yu He

    2003-01-01

    In this paper, the damage to methyl silicone rubber induced by irradiation with protons of 150 keV energy was studied. The surface morphology, tensile strength, Shore hardness, cross-linking density and glass transition temperature were examined. Positron annihilation lifetime spectrum analysis (PALS) was perfomed to reveal the damage mechanisms of the rubber. The results showed that tensile strength and Shore hardness of the rubber increased first and then decreased with increasing irradiation fluence. The PALS characteristics τ3 and I3, as well as the free volume Vf, decreased with increasing irradiation fluence up to 1015 cm-2, and then increased slowly. It indicates that proton irradiation causes a decrease of free volume in the methyl silicone rubber when the fluence is less than l015 cm-2, while the free volume increases when the fluence is greater than 1015 cm-2. The results on cross-linking density indicate that the cross-linking induced by proton irradiation is dominant at smaller proton fluences, increasing the tensile strength and Shore hardness of the rubber, while the degradation of rubber dominates at greater fluence, leading to a decrease of tensile strength and Shore hardness.

  4. Effect of filler water absorption on water swelling properties of natural rubber

    Science.gov (United States)

    Trakuldee, J.; Boonkerd, K.

    2017-07-01

    The efficient water swelling rubber can be obtained by using high hydrophilic rubber such as chloroprene rubber. However, chloroprene rubber is synthetic rubber developed from the petroleum. Recently, many researches try to replace the usage of synthetic rubber with natural rubber. This is not only due to the concerning of environment but the cost reduction as well. However, natural rubber is hydrophobic, thus not absorbing water. To develop the water swelling rubber from natural rubber, the addition of water absorption filler is needed. The study was aimed to formulate water swelling rubber from natural rubber filled with sodium polyacrylate (SA)/sodium bentonite clay (SBC) hybrid filler used to water absorbent. The filler loading was kept constantly at 150 phr. The effect of SA/SBC ratio varied from 1:0, 1:1, 1:2 and 1:3 on the water absorption of the hybrid filled natural rubber was determined. The obtained result showed that the water adsorption proportionally increased with increasing SA loading but decreased with increasing SBC loading. The effect of glycidyl methacrylate (GM) and poly ethylene glycol (PEG) on the water absorption was studied later. The result from a scanning electron microscope depicted that the presence of GM can depress the falling out of SA from the rubber matrix while the presence of PEG increased water absorption.

  5. STUDY ON THE PROPERTIES OF BLEND OF NATURAL RUBBER LATEX/METHYL METHACRYLATE GRAFTED RUBBER LATEX BY GAMMA RADIATION

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Natural rubber latex (NRL) and methyl methacrylate (MMA) grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature.The tensile properties,swelling ratio and permanent set were measured.The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy.Modulus increases from 6.99 Mpa to 9.87 Mpa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose.Elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends.The decreasing trend of permanent set is high up to 5 kGy absorbed dose, and beyond that dose,it becomes almost flat.

  6. Rubber and rubber-like materials, finite-element analyses and simulations, an addendum: a bibliography (1997 2003)

    Science.gov (United States)

    Mackerle, Jaroslav

    2004-09-01

    This paper gives a bibliographical review of the finite-element methods (FEMs) applied to the analysis and simulation of rubber and rubber-like materials. It is a continuation of the author's paper 'Rubber and Rubber-Like Materials, Finite-Element Analyses and Simulations: a Bibliography (1976-1997)' published in 1998 Modelling Simul. Mater. Sci. Eng. 6 171-98. The added bibliography at the end of this article contains 510 references to papers and conference proceedings on the subject that were published in 1997-2003. The following topics are included: incompressible elasticity problems in general, mechanical and material properties, a finite-element library for incompressible materials, contact problems, fracture mechanics, machine elements/structures, material processing and other topics.

  7. Professores homossexuais: suas vivências frente à comunidade escolar

    Directory of Open Access Journals (Sweden)

    Luana Molina

    2012-10-01

    Full Text Available Este trabalho tem como objetivo apresentar uma discussão referente à problemática da vivência diária do professor/professora homossexual frente à instituição escolar, cujo pressuposto inicial parte da premissa que estes professores sofreram e vem sofrendo, algum tipo de preconceito devido sua orientação sexual. No desenvolvimento, partimos para uma abordagem qualitativa e fundamentando-se na análise de discurso, ou seja, conhecendo as experiências de professores e professoras por meio de suas narrativas. Para isso foram entrevistados dois professores gays e uma professora lésbica, todos com ensino superior, que atuam ou atuaram no Ensino Fundamental II e no Ensino Médio. Nossa estratégia metodológica acontece em duas situações: A primeira, por meio de um questionário prévio composto de dez questões de identificação pessoal no intuito de traçar um perfil dos entrevistados. No segundo momento, entrevistas semi – estruturadas, com perguntas que focaram mais especificamente a percepção dos professores/professoras sobre a homofobia na escola. Nosso resultado é composto por relatos onde pudemos identificar a escola como um ambiente que reflete o sexismo que perpassa toda a sociedade, reproduzindo com frequência, as estruturas sociais, reforçando os preconceitos e privilégios de um sexo sobre o outro. Desta forma, percebemos que o heterossexismo está tão arraigado na cultura, que se torna invisível em muitas de suas atitudes quase sutis, como por exemplo, em brincadeiras e piadas. O universo escolar reproduz os preconceitos da sociedade e, na tentativa de evitar o convívio dos alunos heterossexuais, com pessoas homossexuais, faz da homossexualidade o maior alvo da discriminação. Concluímos, portanto, que as desigualdades entre os sexos e a marginalização dos homossexuais acabam gerando vítimas de uma sociedade inacabada, de repressão, opressão e desinformação. Por fim, está sociedade esta em constante

  8. Panorama de las Academias frente al Siglo XXI

    Directory of Open Access Journals (Sweden)

    Zoilo Cuellar Montoya

    1996-12-01

    nombramiento, en ese importante lugar de la salubridad pública, de una persona sin experiencia en esos temas. Las consecuencias de esta decisión no se hicieron esperar y hoy son muy grandes los conflictos existentes en los programas de salud del pueblo colombiano.

    Este hecho, por lo menos en Colombia, marca claramente la posición de los estamentos oficiales y políticos frente al médico y a sus posibilidades como administrador en salud. Más tarde, otro economista, que estuvo casi dos años al mando del Ministerio mencionado, contra viento y marea, engañando con su agilidad verbal a quienes ya al final de su período intentaron intervenir, cohonestado por el silencio cómplice del médico y, porque no decirlo, el de nuestra Academia, logró la puesta en marcha de una nueva ley de seguridad social con una filosofía sana, pero totalmente economicista, y en cuyo desarrollo nunca se tuvo en cuenta al médico: ley que busca el cubrimiento universal en salud del pueblo colombiano, loable sin lugar a dudas, pero impracticable por fallas conceptuales básicas, económicas, operacionales y profesionales (desconocimiento del recurso humano en salud...

  9. Biodegradation of a blended starch/natural rubber foam biopolymer and rubber gloves by Streptomyces coelicolor CH13

    OpenAIRE

    2012-01-01

    Background: The growing problem of environmental pollution caused by synthetic plastics has led to the search for alternative materials such as biodegradable plastics. Of the biopolymers presently under development, starch/natural rubber is one promising alternative. Several species of bacteria and fungi are capable of degrading natural rubber and many can degrade starch. Results: Streptomyces coelicolor CH13 was isolated from soil according to its ability to produce translucent halos on a mi...

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

    OpenAIRE

    Poikelispaa, Minna; Das, Amit; Dierkes, Wilma; 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. A successful application of such composites depends mainly on the degree of dispersion of the nano-sized fillers. Recently, a naturally occurring clay mineral, halloysite nanotubes (HNTs), is inve...

  11. 40 CFR 428.90 - Applicability; description of the pan, dry digestion, and mechanical reclaimed rubber subcategory.

    Science.gov (United States)

    2010-07-01

    ..., dry digestion, and mechanical reclaimed rubber subcategory. 428.90 Section 428.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Pan, Dry Digestion, and Mechanical Reclaimed Rubber Subcategory §...

  12. Predicting the glass transition temperature as function of crosslink density and polymer interactions in rubber compounds

    Science.gov (United States)

    D'Escamard, Gabriella; De Rosa, Claudio; Auriemma, Finizia

    2016-05-01

    Crosslink sulfur density in rubber compounds and interactions in polymer blends are two of the composition elements that affect the rubber compound properties and glass transition temperature (Tg), which is a marker of polymer properties related to its applications. Natural rubber (NR), butadiene rubber (BR) and styrene-butadiene rubber (SBR) compounds were investigated using calorimetry (DSC) and dynamic mechanical analysis (DMA). The results indicate that the Di Marzio's and Schneider's Models predict with accuracy the dependence of Tg on crosslink density and composition in miscible blends, respectively, and that the two model may represent the base to study the relevant "in service" properties of real rubber compounds.

  13. Dynamically vulcanized biobased polylactide/natural rubber blend material with continuous cross-linked rubber phase.

    Science.gov (United States)

    Chen, Yukun; Yuan, Daosheng; Xu, Chuanhui

    2014-03-26

    We prepared a biobased material, dynamically vulcanized polylactide (PLA)/natural rubber (NR) blend in which the cross-linked NR phase owned a continuous network-like dispersion. This finding breaks the traditional concept of a sea-island morphology formed after dynamic vulcanization of the blends. The scan electron microscopy and dissolution/swell experiments provided the direct proof of the continuous cross-linked NR phase. This new biobased PLA/NR blend material with the novel structure is reported for the first time in the field of dynamic vulcanization and shows promise for development for various functional applications.

  14. La jornada anualizada como medio para hacer frente a las variaciones de la demanda.

    OpenAIRE

    2001-01-01

    Se presenta la anualización de la jornada laboral (distribución irregular de la jornada laboral a lo largo del año, sometida a diversas restricciones), como fuente de flexibilidad de los recursoshumanos, para hacer frente a las variaciones en la cantidad

  15. SINTESIS DE DERIVADOS DE FENILALQUILAMINAS CON POSIBLE ACTIVIDAD INHIBITORIA FRENTE A MAO A Y MAO B.

    OpenAIRE

    OSORIO OLIVARES, MAURICIO ENRIQUE

    2004-01-01

    La flavoenzima monoaminooxidasa es la encargada de la desaminación oxidativa de monoaminas endogenas y exogenas. Existen dos ¡soformas de esta enzima la MAO A y la MAO B, las que se diferencian tanto en la selectividad como en la afinidad frente a sus sub 98p.

  16. The unique processing of rubber-insulated wires by radiation

    Science.gov (United States)

    Ishitani, Hayao; Saito, Eisuke; Sasaki, Yasushi

    Ethylene-propylene rubbers are able to be crosslinked (vulcanized) by high energy radiation. The radiation-induced crosslinking of ethylene-propylene copolymer or ethylene-propylene-diene terpolymer depends upon the ethylene/propylene ratio, the molecular weight of the polymer, the unsaturating degree of terpolymer and kinds of tercomponents. The mechanical properties of the crosslinked rubber were affected mainly by the E/P ratio and the molecular weight, and improved by blending of low density polyethylene or ethylene-vinylacetate copolymer. Aging of the rubber, due to kinds and contents of tercomponents, was mostly determined by addition of antioxidants to the compound. We developed EP rubber compounds for wire insulation crosslinked by electron beam radiation and applied to the insulation cores of the ship's cables, in the place of the wire vulcanized conventionally by the pressurized steam in the continuous vulcanizer. The rubber compounds are consisted of ethylene-propylene-diene terpolymer with high ethylene contents, ethylene-vinylacetate copolymer and antioxidants. The high-ethylene polymers are supplied in the shape of pellets, and antioxidants were added to the compounds by means of dry blending of concentrates in which antioxidants are mixed into pellets of ethylene copolymer. The EP rubbers were covered on the copper wire by the extruder, used to plastic material, and irradiated with the electron beam from an accelerator. These insulated cores manufactured on radiation processing had the excellent properties, particularly aging and electrical properties. Further, they are more simply colored. Therefore, they will be considered to be used to other applications. This method of manufacturing of the rubber-insulated wires made it possible to reduce both the material costs by simple compounding and the operating costs by radiation-induced crosslinking, to compare with the conventional compounding and vulcanizing process, in which the materials are

  17. Interaction of Chloroprene and Nitrile- Butadiene Rubber with Lubricating Greases and Base Oils

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The present communication addresses compatibility of two synthetic rubber types, chloroprene and nitrilebutadiene ones, with a number of base oils of petroleum origin and lubricating greases produced thereof. Four base oils,including three naphthenic products with varying degrees of refining and one paraffinic product,were compared with each other in terms of their effect on the rubbers. Degenerative changes occurring in the rubbers on contact with the oils and greases were studied using accelerated ageing tests. Alterations in rubber parameters, such as hardness, weight and glass transition temperature, caused by interaction with oil were monitored. The main physicochemical mechanisms standing behind the changes observed in the rubber properties were found to be (i) migration of plasticizer from rubber into the oil phase, (ii) absorption of oil by rubber,and (iii) oxidation of rubber. An increase in glass transition temperature (Tg) of rubber aged in a base oil or grease was considered as an indirect indication that the plasticizer had migrated out of rubber;the plasticizer accumulation in the oil phase being directly confirmed by gas chromatography. In order to suppress the plasticizer migration, oil additivation with dioctyl adipate (DOA), a common plasticizer used in rubber formulations, was attempted. However, the BOA-additivated oils, while reducing plasticizer migration, were found to cause more swelling than the original oils in the case of chloroprene rubber. As an alternative, replacement of BOA by an alkylated aryl phosphate in nitrile- butadiene rubber formulations was considered, but it did not solve the problem either.The results of this study suggest conclusively that the type of rubber, the plasticizer, and the base oil are all the crucial parameters that should be considered when matching rubber with oil in real- life applications. Interaction of rubber with base oils and with greases produced thereof is largely controlled by (i) solvency of the

  18. 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

  19. A unified approach to an augmented Burgers equation for the propagation of sonic booms.

    Science.gov (United States)

    Yamamoto, Masafumi; Hashimoto, Atsushi; Aoyama, Takashi; Sakai, Takeharu

    2015-04-01

    Nonlinear propagation through a relaxing atmosphere of pressure disturbances extracted from a computational fluid dynamics (CFD) solution of the flow around a supersonic aircraft is simulated using an augmented Burgers equation. The effects of nonlinearity, geometrical spreading, atmospheric inhomogeneity, thermoviscous attenuation, and molecular vibration relaxation are taken into account. The augmented Burgers equation used for sonic boom propagation calculations is often solved by the operator splitting method, but numerical difficulties arise with this approach when dissipation is not effective. By re-examining the solution algorithms for the augmented Burgers equation, a stable method for handling the relaxation effect has been developed. This approach can handle the Burgers equation in a unified manner without operator splitting and, therefore, the resulting scheme is twice as fast as the original one. The approach is validated by comparing it with an analytical solution and a detailed CFD of dispersed plane wave propagation. In addition, a rise time prediction of low-boom supersonic aircraft is demonstrated.

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

    Directory of Open Access Journals (Sweden)

    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