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Sample records for blue rubber bleb

  1. Severe Blue Rubber Bleb Nevus Syndrome in a Neonate

    DEFF Research Database (Denmark)

    Hansen, L; Wewer, V; Pedersen, S; Matzen, P; Paerregaard, A

    2008-01-01

    We report on a child with blue rubber bleb nevus syndrome (BRBNS) presenting during the first days of life with severe bleeding from the upper gastrointestinal tract. Medical treatment with methylprednisolone, cyklokapron, interferon 1 alpha and numerous blood transfusions were given to control...... problems. The case is unique because 1) it is the first neonatal case with BRBNS and severe gastrointestinal bleeding; 2) the patient was successfully treated by endoscopic electrocoagulation; and 3) the long-term follow-up. The use of electrocoagulation appears to have been effective and ablation of the...... bleeding during the first 3 years of life. Afterwards repeated endoscopic electrocoagulations were performed over a period of one year resulting in a termination of bleeding episodes. At ten years of age the patient developed spastic diplegia with slight walking disabilities, coordination and fine motor...

  2. Blue rubber bleb nevus syndrome: a report of one case associated with recurrent epistaxis

    Institute of Scientific and Technical Information of China (English)

    LIU Qiong; CHEN Yi-peng; LI You-ming

    2007-01-01

    @@ Blue rubber bleb nevus syndrome (BRBNS), or Bean's syndrome, is a rare angiomatosis characterized by distinctive cutaneous and gastrointestinal venous malformations that usually cause massive or occult gastrointestinal hemorrhage and iron deficiency anemia secondary to the bleeding episodes.

  3. Unilateral, Linear Blue Rubber Bleb Nevus Syndrome (Bean's syndrome): An Unfamiliar Presentation: First Case from India

    Science.gov (United States)

    Sancheti, Karan; Podder, Indrashis; Das, Anupam; Choudhury, Sourav; Chandra, Somodyuti; Gharami, Ramesh Chandra

    2015-01-01

    Blue rubber bleb nevus syndrome (BRBNS) also called Bean's syndrome is a rare disorder characterized by multiple cutaneous venous malformations in association with visceral lesions, most commonly affecting the gastrointestinal tract. We report here, a 21-year-old woman patient, who presented with unilateral, blaschkoid distribution of cutaneous venous malformations along with blue rubber bleb nevus and recurrent episodes of hematochezia due to vascular lesions in the sigmoid colon; likely to be a case of BRBNS. The unusual unilateral, blaschkoid distribution of BRBNS prompted this present report. PMID:26677281

  4. The management of ophthalmic involvement in blue rubber bleb nevus syndrome

    Directory of Open Access Journals (Sweden)

    Petek, Bradley

    2014-07-01

    Full Text Available [english] Objective: Blue rubber bleb nevus syndrome is a rare vascular disease most commonly associated with venous malformations of the skin and the gastrointestinal tract. Few ophthalmic cases have been reported to date, and no clear treatment regimen exists. We describe the case of a 59-year-old man, along with a review of literature, to help in the future diagnosis and treatment of patients with the disease. Methods: This paper is an observational case report and a review of medical literature on the syndrome from 1981 to present.Results: Our patient developed a dural arteriovenous fistula in his orbit after being diagnosed with a familial form of blue rubber bleb nevus syndrome. Multiple endovascular embolization procedures eliminated all of his ocular symptoms. Surgical procedures were also successful in other cases reviewed, and similar symptoms were seen across cases.Conclusions: Comparing our case with other ophthalamic reports in literature, surgical intervention appears to be a plausible long-term treatment for optic manifestations of blue rubber bleb nevus syndrome. Systemic therapies, including sirolimus and corticosteroids, have had limited success in the long-term treatment of other forms of blue rubber bleb nevus syndrome, and therefore are not recommended in the treatment of ocular symptoms.

  5. The management of ophthalmic involvement in blue rubber bleb nevus syndrome

    OpenAIRE

    Petek, B; Jones, RL

    2014-01-01

    Objective: Blue rubber bleb nevus syndrome is a rare vascular disease most commonly associated with venous malformations of the skin and the gastrointestinal tract. Few ophthalmic cases have been reported to date, and no clear treatment regimen exists. We describe the case of a 59-year-old man, along with a review of literature, to help in the future diagnosis and treatment of patients with the disease. Methods: This paper is an observational case report and a review of medical literature o...

  6. The management of ophthalmic involvement in blue rubber bleb nevus syndrome

    OpenAIRE

    Petek, Bradley; Jones, Robin L.

    2014-01-01

    [english] Objective: Blue rubber bleb nevus syndrome is a rare vascular disease most commonly associated with venous malformations of the skin and the gastrointestinal tract. Few ophthalmic cases have been reported to date, and no clear treatment regimen exists. We describe the case of a 59-year-old man, along with a review of literature, to help in the future diagnosis and treatment of patients with the disease. Methods: This paper is an observational case report and a review of medical lite...

  7. The value of double balloon enteroscopy in diagnosing blue rubber bleb naevus syndrome: a case report.

    LENUS (Irish Health Repository)

    O'Kelly, Fardod

    2010-01-01

    Blue rubber bleb naevus syndrome is a rare vascular disorder associated with multiple gastrointestinal haemangiomas that have the potential for life-threatening haemorrhage. These may be difficult to diagnose, and have classically been described using computed tomographic studies and\\/or mesenteric angiography. Resected surgical specimens of these lesions, especially in the small bowel, have often been extensive and poorly localized. The recent advent and progressive development of double balloon enteroscopy has allowed the direct visualization and marking of these enteric lesions and serves as a valuable adjunct not only in diagnosis but also planning prior to surgery to allow accurate estimate of the extent of resection.

  8. Unilateral, linear blue rubber bleb nevus syndrome (Bean′s syndrome: An unfamiliar presentation: First case from India

    Directory of Open Access Journals (Sweden)

    Karan Sancheti

    2015-01-01

    Full Text Available Blue rubber bleb nevus syndrome (BRBNS also called Bean′s syndrome is a rare disorder characterized by multiple cutaneous venous malformations in association with visceral lesions, most commonly affecting the gastrointestinal tract. We report here, a 21-year-old woman patient, who presented with unilateral, blaschkoid distribution of cutaneous venous malformations along with blue rubber bleb nevus and recurrent episodes of hematochezia due to vascular lesions in the sigmoid colon; likely to be a case of BRBNS. The unusual unilateral, blaschkoid distribution of BRBNS prompted this present report.

  9. Blue rubber bleb nevus syndrome: a rare presentation of late-onset anemia and lower gastrointestinal bleeding without cutaneous manifestations

    OpenAIRE

    Goud, Aditya; Abdelqader, Abdelhai; Walters, Jamie; Selinger, Stephen

    2016-01-01

    Blue rubber bleb nevus syndrome (BRBNS) is a congenital disorder with characteristic venous anomalies that can present with varying degree of blood loss. The most clinically significant symptoms in adults include gastrointestinal (GI) bleeding and iron deficiency anemia. Severe complications can include intestinal torsion, intussusception, and even perforation, with each leading to significant morbidity and mortality. This report serves to give a brief understanding of this rare disease along...

  10. Blue rubber bleb nevus syndrome: a rare presentation of late-onset anemia and lower gastrointestinal bleeding without cutaneous manifestations

    Science.gov (United States)

    Goud, Aditya; Abdelqader, Abdelhai; Walters, Jamie; Selinger, Stephen

    2016-01-01

    Blue rubber bleb nevus syndrome (BRBNS) is a congenital disorder with characteristic venous anomalies that can present with varying degree of blood loss. The most clinically significant symptoms in adults include gastrointestinal (GI) bleeding and iron deficiency anemia. Severe complications can include intestinal torsion, intussusception, and even perforation, with each leading to significant morbidity and mortality. This report serves to give a brief understanding of this rare disease along with current diagnostic and therapeutic options. PMID:26908380

  11. Blue rubber bleb nevus syndrome: a rare presentation of late-onset anemia and lower gastrointestinal bleeding without cutaneous manifestations

    Directory of Open Access Journals (Sweden)

    Aditya Goud

    2016-02-01

    Full Text Available Blue rubber bleb nevus syndrome (BRBNS is a congenital disorder with characteristic venous anomalies that can present with varying degree of blood loss. The most clinically significant symptoms in adults include gastrointestinal (GI bleeding and iron deficiency anemia. Severe complications can include intestinal torsion, intussusception, and even perforation, with each leading to significant morbidity and mortality. This report serves to give a brief understanding of this rare disease along with current diagnostic and therapeutic options.

  12. [Anesthetic Management of a Pediatric Case of Blue Rubber Bleb Nevi Syndrome Combined with Small-intestinal Intussusception].

    Science.gov (United States)

    Ueno, Takeshi; Komasawa, Nobuyasu; Matsunami, Sayuri; Majima, Nozomi; Kusaka, Yusuke; Minami, Toshiaki

    2016-04-01

    We report the anesthetic management of a pediatric case of blue rubber bleb nevi syndrome combined with small-intestinal intussusception. A 2-year-old girl was transferred to our hospital for small-intestinal intussusception. Emergent ablation of the upper gastrointestinal tract nevus under general anesthesia was planned. Given the presence of several nevi in the oral and pharyngeal space, we utilized the McGRATH MAC (McGRATH; Aircraft Medical Ltd, United Kingdom) laryngoscope for gentle and stress-free tracheal intubation. The venous line was kept patent preoperatively, and rapid-sequence intubation was performed with the McGRATH (size 2 pediatric blade). A 4.5-mm tracheal tube was inserted uneventfully under direct visualization. The trachea was observed and the tube maintained in a proper position with a bronchofiberscope. During the procedure, cuff volume was regulated to avoid excessive increase by upper gastrointestinal endoscope insertion. The girl was extubated in the operating room and showed no postoperative complications such as hemorrhage or hoarseness. PMID:27188112

  13. Severe Blue Rubber Bleb Nevus Syndrome in a Neonate

    DEFF Research Database (Denmark)

    Hansen, L; Wewer, V; Pedersen, S; Matzen, P; Paerregaard, A

    2008-01-01

    bleeding during the first 3 years of life. Afterwards repeated endoscopic electrocoagulations were performed over a period of one year resulting in a termination of bleeding episodes. At ten years of age the patient developed spastic diplegia with slight walking disabilities, coordination and fine motor...... problems. The case is unique because 1) it is the first neonatal case with BRBNS and severe gastrointestinal bleeding; 2) the patient was successfully treated by endoscopic electrocoagulation; and 3) the long-term follow-up. The use of electrocoagulation appears to have been effective and ablation of the...

  14. Bleb Nucleation through Membrane Peeling

    CERN Document Server

    Alert, Ricard

    2016-01-01

    We study the nucleation of blebs, i.e., protrusions arising from a local detachment of the membrane from the cortex of a cell. Based on a simple model of elastic linkers with force-dependent kinetics, we show that bleb nucleation is governed by membrane peeling. By this mechanism, the growth or shrinkage of a detached membrane patch is completely determined by the linker kinetics, regardless of the energetic cost of the detachment. We predict the critical nucleation radius for membrane peeling and the corresponding effective energy barrier. These may be typically smaller than those predicted by classical nucleation theory, implying a much faster nucleation. We also perform simulations of a continuum stochastic model of membrane-cortex adhesion to obtain the statistics of bleb nucleation times as a function of the stress on the membrane. The determinant role of membrane peeling changes our understanding of bleb nucleation and opens new directions in the study of blebs.

  15. Bleb Nucleation through Membrane Peeling

    Science.gov (United States)

    Alert, Ricard; Casademunt, Jaume

    2016-02-01

    We study the nucleation of blebs, i.e., protrusions arising from a local detachment of the membrane from the cortex of a cell. Based on a simple model of elastic linkers with force-dependent kinetics, we show that bleb nucleation is governed by membrane peeling. By this mechanism, the growth or shrinkage of a detached membrane patch is completely determined by the linker kinetics, regardless of the energetic cost of the detachment. We predict the critical nucleation radius for membrane peeling and the corresponding effective energy barrier. These may be typically smaller than those predicted by classical nucleation theory, implying a much faster nucleation. We also perform simulations of a continuum stochastic model of membrane-cortex adhesion to obtain the statistics of bleb nucleation times as a function of the stress on the membrane. The determinant role of membrane peeling changes our understanding of bleb nucleation and opens new directions in the study of blebs.

  16. Three mechanical models for blebbing and multi-blebbing

    KAUST Repository

    Woolley, T. E.

    2014-06-17

    Membrane protrusions known as blebs play important roles in many cellular phenomena. Here we present three mathematical models of the bleb formation, which use biological insights to produce phenotypically accurate pressure-driven expansions. First, we introduce a recently suggested solid mechanics framework that is able to create blebs through stretching the membrane. This framework is then extended to include reference state reconfigurations, which models membrane growth. Finally, the stretching and reconfiguring mechanical models are compared with a much simpler geometrically constrained solution. This allows us to demonstrate that simpler systems are able to capture much of the biological complexity despite more restrictive assumptions. Moreover, the simplicity of the spherical model allows us to consider multiple blebs in a tractable framework. © 2014 The authors 2014. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

  17. A comparative investigation on adsorption performances of mesoporous activated carbon prepared from waste rubber tire and activated carbon for a hazardous azo dye-Acid Blue 113

    International Nuclear Information System (INIS)

    Research highlights: → The system is cheap, efficient and fast for the removal of dyes from waters. → Higher adsorption capacity is due to higher mesoporous volume of the adsorbent. → The rate determining step of the adsorption process is particle diffusion. - Abstract: A mesoporous carbon developed from waste tire rubber, characterized by chemical analysis, FTIR, and SEM studies, was used as an adsorbent for the removal and recovery of a hazardous azo dye, Acid Blue 113. Surface area, porosity, and density were determined. The adsorption of the dye over the prepared adsorbent and a commercial activated carbon was achieved under different pH, adsorbate concentration, sieve size, adsorbent dosage, contact time and temperature conditions. Langmuir and Freundlich adsorption isotherm models were applied and thermodynamic parameters were calculated. Kinetic studies indicated that the adsorption process follow first order kinetics and particle diffusion mechanisms are operative. By percolating the dye solution through fixed-bed columns the bulk removal of the Acid Blue 113 was carried out and necessary parameters were determined to find out the percentage saturation of both the columns. Recovery of the dye was made by eluting 0.1 M NaOH through the column.

  18. Computer simulation of cytoskeleton-induced blebbing in lipid membranes

    DEFF Research Database (Denmark)

    Spangler, E. J.; Harvey, C. W.; Revalee, J. D.;

    2011-01-01

    Blebs are balloon-shaped membrane protrusions that form during many physiological processes. Using computer simulation of a particle-based model for self-assembled lipid bilayers coupled to an elastic meshwork, we investigated the phase behavior and kinetics of blebbing. We found that blebs form ...

  19. Evaluation of filtering blebs using the 'Wuerzburg bleb classification score' compared to clinical findings

    OpenAIRE

    Furrer, Sandra; Menke, Marcel N; Funk, Jens; Töteberg-Harms, Marc

    2012-01-01

    To determine the agreement between intraocular pressure and the 'Wuerzburg bleb classification score', as well as between single items of the score and intraocular pressure. Interobserver variability was analyzed.

  20. Computer Simulation of Cytoskeleton-Induced Blebbing in Lipid Membranes

    CERN Document Server

    Spangler, Eric J; Revalee, Joel D; Kumar, P B Sunil; Laradji, Mohamed

    2011-01-01

    Blebs are balloon-shaped membrane protrusions that form during many physiological processes. Using computer simulation of a particle-based model for self-assembled lipid bilayers coupled to an elastic meshwork, we investigated the phase behavior and kinetics of blebbing. We found that blebs form for large values of the ratio between the areas of the bilayer and the cytoskeleton. We also found that blebbing can be induced when the cytoskeleton is subject to a localized ablation or a uniform compression. The results obtained are qualitatively in agreement with the experimental evidence and the model opens up the possibility to study the kinetics of bleb formation in detail.

  1. Complications and Management of the Filtration Bleb

    Institute of Scientific and Technical Information of China (English)

    Clement; W; N; Chan

    1992-01-01

    Filtration surgery is the commonest operation performed for closed angle or open angle glaucoma when medical treatment or laser trabeculoplasty has failed to control the intraocular pressure. It is characterized by the formation of an artificial drainage fistula between the anterior chamber and subconjunctival space. The successful operation is evidenced by the appearance of a subconjunctival filtration bleb which in turn depends on the patency of this pathway. Despite numerous modification, the procedu...

  2. Cellular blebs: pressure-driven, axisymmetric, membrane protrusions

    KAUST Repository

    Woolley, Thomas E.

    2013-07-16

    Blebs are cellular protrusions that are used by cells for multiple purposes including locomotion. A mechanical model for the problem of pressure-driven blebs based on force and moment balances of an axisymmetric shell model is proposed. The formation of a bleb is initiated by weakening the shell over a small region, and the deformation of the cellular membrane from the cortex is obtained during inflation. However, simply weakening the shell leads to an area increase of more than 4 %, which is physically unrealistic. Thus, the model is extended to include a reconfiguration process that allows large blebs to form with small increases in area. It is observed that both geometric and biomechanical constraints are important in this process. In particular, it is shown that although blebs are driven by a pressure difference across the cellular membrane, it is not the limiting factor in determining bleb size. © 2013 Springer-Verlag Berlin Heidelberg.

  3. Amniotic Membrane Transplantation for Exuberant Bleb Following Filtration Surgery

    Directory of Open Access Journals (Sweden)

    Lan-Hsin Chuang

    2006-08-01

    Full Text Available The use of antimetabolites in filtration surgery, cystic, large, leaking blebs often lead tocomplications. We report a case of glaucoma that received amniotic membrane transplantationfor repairing the exuberant bleb. This female patient had a history of several eye surgeries,including a scleral buckle and cyclocryotherapy for one eye and the other received filteringsurgery. The latter had been revised once with autologous conjunctival advancementafter an episode of bleb leakage. The large bleb, overlaying the cornea 3 mm from the limbus,had caused corneal erosion beneath the bleb and the patient suffered burning sensations.Further conjunctival advancement of the exuberant bleb is difficult to achive, because it hadbeen revised once with this treatment. Amniotic membrane was used for further reconstructionafter the excision of the pre-existing bleb. A normal intraocular pressure was regained.The symptom of burning sensations subsequently subsided. A ten-month follow-up was conducted.Amniotic membrane transplantation is a feasible option for exuberant or late onsetbleb leakage, to prevent further destruction of ocular surface tissue and to maintain theintraocular pressure.

  4. Surgical Repair of Leaking Filtering Blebs Using Two Different Techniques

    Directory of Open Access Journals (Sweden)

    António B Melo

    2012-01-01

    Full Text Available Purpose: To report the outcomes of two different surgical techniques for the repair of late onset bleb leakage following trabeculectomy. Methods: This retrospective study includes 21 eyes of 20 patients with prior trabeculectomy and late-onset bleb leaks; 14 eyes underwent excision of the filtering bleb together with conjunctival advancement while in the other 7 eyes the bleb was retained but de-epithelialized before conjunctival advancement. Success was defined as resolution of leakage with no need for additional glaucoma surgery together with intraocular pressure (IOP of 5-21 mmHg. Complete and qualified success was considered when the above mentioned was achieved without or with glaucoma medications, respectively. Results: Mean duration of follow-up was 20.3΁14.4 months. No significant difference was observed between the two groups in terms of complete, qualified and overall success rates (P>0.05, however more antiglaucoma medications were necessary in the bleb excision group (P=0.02. Conclusions: Both surgical techniques of bleb repair were comparably effective, however the bleb de-epithelialization technique was associated with less need for glaucoma medications after the procedure.

  5. The size, shape, and dynamics of cellular blebs

    OpenAIRE

    Lim, Fong Yin; Chiam, Keng-Hwee; Mahadevan, L.

    2012-01-01

    A cellular bleb grows when a portion of the cell membrane detaches from the underlying cortex under the influence of a cytoplasmic pressure. We develop a quantitative model for the growth and dynamics of these objects in a simple two-dimensional setting. In particular, we first find the minimum cytoplasmic pressure and minimum unsupported membrane length for a stationary bleb to nucleate and grow as a function of the membrane-cortex adhesion. We next show how a bleb may travel around the peri...

  6. Morphology of functioning trabeculectomy blebs using anterior segment optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Mayuri B Khamar

    2014-01-01

    Full Text Available Purpose: To image trabeculectomy blebs using anterior segment optical coherence tomography (AS-OCT, and to correlate the bleb morphologic features at one month postoperatively with bleb function at six months. Materials and Methods: This prospective, observational study included 56 eyes undergoing trabeculectomy with MMC, followed up for minimum of six months. Postoperatively, bleb imaging was done using AS-OCT at one and six month. Bleb morphology was assessed for bleb wall reflectivity, bleb pattern in multiform reflectivity, visibility of drainage route and presence of hyper-reflectivity area. Bleb function was considered successful if IOP was <18 mmHg without medication at six month. Bleb morphology one month postoperatively was correlated with bleb function at six months. Results: At six months successful bleb function was noted in 44 (81.5% eyes. Morphology of bleb at one month showed uniform bleb wall reflectivity in 6 eyes (11% and multiform wall reflectivity in 48 eyes (89%. In eyes with multiform wall reflectivity, microcysts with multiple layers was seen in 26 eyes (48%, microcysts with subconjunctival separation in 12 eyes (22% and only microcyst in 10 eyes (19%. When bleb features at one month were correlated with the bleb function at six months, logistic regression analysis revealed that blebs with multiform reflectivity with multiple internal layers with microcysts were associated with higher chances of success (P < 0.001. Conclusion : AS-OCT demonstrated early bleb morphological features that may be used to predict the functioning of a bleb. Multiform bleb wall reflectivity with a pattern of multiple internal layers and microcysts was associated with increased chances of success of a bleb.

  7. Rubber Dams

    OpenAIRE

    Kumaraswamy, Mohan

    2002-01-01

    One element of the CIVCAL project Web-based resources containing images, tables, texts and associated data on the construction of the Rubber Dams. Rubber dam construction is a relatively recent technological breakthrough. It was introduced to Hong Kong in the early 1960's and to date (Jan '99), 20 rubber dams have been installed in Hong Kong. Most of the dams are used to impound water for irrigation.

  8. Rubber gloves

    International Nuclear Information System (INIS)

    Rubber gloves are made by irradiating rubber latex containing a sensitizer with ionizing radiation to effect cross-linking. A glove shaped former is then dipped into the irradiated material and dried. The sensitizer can be a mono- or di-unsaturated monomer, such as 1,3-butylene glycol diacrylate. The rubber gloves are capable of maintaining stable quality without any time elapsing deterioration and of preventing any pollutive exhaust gases such as SOx, NOx, hydrogen cyanide, carbon monoxide and the like when old rubber gloves are burned in the scrap treatment in an incinerator. (author)

  9. 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…

  10. Intra-bleb hematoma and hyphema following digital ocular compression

    Directory of Open Access Journals (Sweden)

    Sagar Bhargava

    2014-01-01

    Full Text Available We report successful outcome of a huge post- trabeculectomy intra-bleb hematoma and hyphema that occurred following digital ocular compression. The patient was a 64-year-old lady suffering from bilateral primary angle closure glaucoma and cataract. She was on anti-platelet therapy. She underwent single-site phacoemulsification, intra-ocular lens implantation and trabeculectomy with mitomycin C in the right eye. The trabeculectomy was under-filtering. She was asked to perform digital ocular compression thrice daily. On 15 th post-operative day, she presented with a huge intra-bleb hematoma and hyphema. The hematoma did not respond to conservative measures and was drained to prevent bleb failure. We recommend caution in the consideration of digital ocular compression in patients on prophylactic anti-coagulation.

  11. NEEDLE REVISION WITH MITOMYCIN-C IN ENCAPSULATED BLEBS

    Directory of Open Access Journals (Sweden)

    R Zarei

    2008-08-01

    Full Text Available "nThe most common cause of failure during the first trimester after trabeculectomy is encapsulated bleb and needling bleb revision is a less invasive method in the management of refractory cases. The purpose of this study is to determine the efficacy and safety of mitomycin-C (MMC augmented bleb revision of failed filtration surgery. This study is a before-after (paired observation. 33 patients with failed trabeculectomy because of bleb encapsulation, whose intraocular pressure (IOP was not reduced under 21 mmHg despite of medications and digital massage , underwent needling bleb revision and subconjunctival injection of 0.1 ml MMC (0.4 mg/ml.The mean follow-up time was 9.24 ± 5.27 months (1-20 months. Statistical analysis of the data included the paired two-tailed Student's t test for preoperative and postoperative IOP and number of medications. 36 needling procedures (mean, 1.09 ± 0.21 revisions per eye were performed on 33 eyes. Patients were between 10-80 years old (mean, 45.67 ± 22.41 years and mean follow-up was 9.24 ± 5.27 months. IOP decreased from 29.06 ± 5.03 mmHg to 18.21 ± 6.76 mmHg at last follow-up (P= 0.000. Antiglaucoma medications decreased from 2.18 ± 0.58 to 1.36 ± 0.29 at last follow-up (P= 0.000.Overall, 6 (18.2% of 33 cases achieved a complete success and 20 (60.6% of cases achieved a qualified success. The complications of this procedure were subconjunctival hemorrhage (17 cases, hyphema (5 cases and conjunctival button hole (2 cases. Needling bleb revision with mitomycin-C appears to be an effective and relatively safe way to revive failed filtration surgery.

  12. Correlation between hyperthermia-induced membrane blebbing and survival in G/sub 1/ CHO cells

    International Nuclear Information System (INIS)

    G/sub 1/ cells, obtained by mitotic selection, were incubated and heated in suspension culture at 45.50C for 3 - 20 min. Varying degrees of membrane blebbing were induced, ranging from nonblebbed cells indistinguishable from control cells to those with blebs larger than the cell itself. Both the proportion of cells exhibiting blebbing and the mean diameter of the blebs increased with duration of heating. A cell scoring system based on the ratio of the diameter of the largest bleb relative to that of the cell was established. Scoring was done within 30 min after heating, after which time blebs either were released from the cells or were reabsorbed. The percent of heated cells having blebs smaller than 50% of the cell diameter equalled the percent of cells survivivg. This relationship was confirmed by scoring single cells both for blebbing and for their ability to form colonies. Electron microscopy demonstrated that the subcellular organelles, except for ribosomes and microtubules, were absent from the blebs, and found within a juxtanuclear region in the blebbed cells. Freeze fracture replicas revealed no changes in membrane ultrastructure, either on the blebs or cell body. The only exception was a small number of blebs which contained bald patches devoid of membrane particles

  13. Cell Surface Mechanochemistry and the Determinants of Bleb Formation, Healing, and Travel Velocity.

    Science.gov (United States)

    Manakova, Kathryn; Yan, Huaming; Lowengrub, John; Allard, Jun

    2016-04-12

    Blebs are pressure-driven cell protrusions implicated in cellular functions such as cell division, apoptosis, and cell motility, including motility of protease-inhibited cancer cells. Because of their mechanical nature, blebs inform us about general cell-surface mechanics, including membrane dynamics, pressure propagation throughout the cytoplasm, and the architecture and dynamics of the actin cortex. Mathematical models including detailed fluid dynamics have previously been used to understand bleb expansion. Here, we develop mathematical models in two and three dimensions on longer timescales that recapitulate the full bleb life cycle, including both expansion and healing by cortex reformation, in terms of experimentally accessible biophysical parameters such as myosin contractility, osmotic pressure, and turnover of actin and ezrin. The model provides conditions under which blebbing occurs, and naturally gives rise to traveling blebs. The model predicts conditions under which blebs travel or remain stationary, as well as the bleb traveling velocity, a quantity that has remained elusive in previous models. As previous studies have used blebs as reporters of membrane tension and pressure dynamics within the cell, we have used our system to investigate various pressure equilibration models and dynamic, nonuniform membrane tension to account for the shape of a traveling bleb. We also find that traveling blebs tend to expand in all directions unless otherwise constrained. One possible constraint could be provided by spatial heterogeneity in, for example, adhesion density. PMID:27074688

  14. A Pleuroperitoneal Bleb Mimicking an Intrathoracic Mass in a Cirrhotic Patient: Three Case Reports

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun Ho; Lee, Kyung Hee; Cho, Soon Gu; Jeon, Yong Sun [Inha University Hospital, Incheon (Korea, Republic of)

    2009-07-15

    In a cirrhotic patient, an increase in intra-abdominal pressure due to the presence of ascites might lead to a small pleuroperitoneal bleb of the peritoneum from congenital defects in the hemithorax. This lesion may appear as an intrathoracic mass as seen on a simple chest radiograph. A CT image may be helpful to differentiate an ascitic pleuroperitoneal bleb from an intrathoracic mass. We present three cases of a pleuroperitoneal bleb in patients with liver cirrhosis and ascites.

  15. Postpartum Blues

    Medline Plus

    Full Text Available ... baby blues). What are the baby blues? The word "blues" is not really correct since women with ... baby blues). What are the baby blues? The word "blues" is not really correct since women with ...

  16. Bleb Point: Mimicker of Pneumothorax in Bullous Lung Disease

    Directory of Open Access Journals (Sweden)

    Gelabert, Christopher

    2015-05-01

    Full Text Available In patients presenting with severe dyspnea, several diagnostic challenges arise in distinguishing the diagnosis of pneumothorax versus several other pulmonary etiologies like bullous lung disease, pneumonia, interstitial lung disease, and acute respiratory distress syndrome. Distinguishing between large pulmonary bullae and pneumothorax is of the utmost importance, as the acute management is very different. While multiple imaging modalities are available, plain radiographs may be inadequate to make the diagnosis and other advanced imaging may be difficult to obtain. Ultrasound has a very high specificity for pneumothorax. We present a case where a large pulmonary bleb mimics the lung point and therefore inaccurately suggests pneumothorax. [West J Emerg Med. 2015;16(3:447–449.

  17. SH4-domain-induced plasma membrane dynamization promotes bleb-associated cell motility.

    Science.gov (United States)

    Tournaviti, Stella; Hannemann, Sebastian; Terjung, Stefan; Kitzing, Thomas M; Stegmayer, Carolin; Ritzerfeld, Julia; Walther, Paul; Grosse, Robert; Nickel, Walter; Fackler, Oliver T

    2007-11-01

    SH4 domains provide bipartite membrane-targeting signals for oncogenic Src family kinases. Here we report the induction of non-apoptotic plasma membrane (PM) blebbing as a novel and conserved activity of SH4 domains derived from the prototypic Src kinases Src, Fyn, Yes and Lck as well as the HASPB protein of Leishmania parasites. SH4-domain-induced blebbing is highly dynamic, with bleb formation and collapse displaying distinct kinetics. These reorganizations of the PM are controlled by Rho but not Rac or Cdc42 GTPase signalling pathways. SH4-induced membrane blebbing requires the membrane association of the SH4 domain, is regulated by the activities of Rock kinase and myosin II ATPase, and depends on the integrity of F-actin as well as microtubules. Endogenous Src kinase activity is crucial for PM blebbing in SH4-domain-expressing cells, active Src and Rock kinases are enriched in SH4-domain-induced PM blebs, and PM blebbing correlates with enhanced cell invasion in 3D matrices. These results establish a novel link between SH4 domains, Src activity and Rho signalling, and implicate SH4-domain-mediated PM dynamization as a mechanism that influences invasiveness of cells transformed by SH4-domain-containing oncoproteins. PMID:17959630

  18. Rubber glove wearing device

    International Nuclear Information System (INIS)

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

  19. Early cystic bleb needling revision after glaucoma filtering surgery with toxic keratopathy

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2014-01-01

    Full Text Available Clinical case of high thin-wall cystic limited filtering bleb needling revision in the early post-op period after trabeculectomy with sinusotomy accompanied by toxic keratopathy is presented. Optical coherence tomography (OCT demonstrated that filtering bleb height was 2700 μm and bleb wall thickness was 70 μm. Bleb needling revision with its lateralwall dissection and subconjunctival injection of dexamethasone, fluorouracil, and ranibizumab near to the bleb site was performed. In 1.5 hours after the procedure, bleb height decreased to 550 μm (by 5 times while bleb wall thickness increased up to 100 μm. Topical antibacterial, steroid, and non-steroid anti-inflammatory therapy was recommended. The next day IOP level reduced from 11 mm Hg to 4.5 mm Hg. It was accompanied by choroidal effusion that was managed conservatively with cycloplegic agents (drops and injections for 3 days. On day 6, central corneal edema affecting all layers, Descemet’s membrane folds, and ocular hypertension were revealed. Metabolic therapy resolved corneal edema within 3 days. Re-needling bleb revision decreased IOP level to 6.2 mm Hg. This resulted in transient Descemet’s membrane folds. This paper describes filtering bleb needling revision with its lateral wall dissection and anti-inflammatory, cytostatic, and anti-VEGF agents use to prolong glaucoma filtering surgery effect in excessive scarring. The procedure was accompanied by toxic corneal endothelium decompensation with corneal edema and Descemet’s membrane folds treated with active metabolic therapy.

  20. Early cystic bleb needling revision after glaucoma filtering surgery with toxic keratopathy

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2015-01-01

    Full Text Available Clinical case of high thin-wall cystic limited filtering bleb needling revision in the early post-op period after trabeculectomy with sinusotomy accompanied by toxic keratopathy is presented. Optical coherence tomography (OCT demonstrated that filtering bleb height was 2700 μm and bleb wall thickness was 70 μm. Bleb needling revision with its lateralwall dissection and subconjunctival injection of dexamethasone, fluorouracil, and ranibizumab near to the bleb site was performed. In 1.5 hours after the procedure, bleb height decreased to 550 μm (by 5 times while bleb wall thickness increased up to 100 μm. Topical antibacterial, steroid, and non-steroid anti-inflammatory therapy was recommended. The next day IOP level reduced from 11 mm Hg to 4.5 mm Hg. It was accompanied by choroidal effusion that was managed conservatively with cycloplegic agents (drops and injections for 3 days. On day 6, central corneal edema affecting all layers, Descemet’s membrane folds, and ocular hypertension were revealed. Metabolic therapy resolved corneal edema within 3 days. Re-needling bleb revision decreased IOP level to 6.2 mm Hg. This resulted in transient Descemet’s membrane folds. This paper describes filtering bleb needling revision with its lateral wall dissection and anti-inflammatory, cytostatic, and anti-VEGF agents use to prolong glaucoma filtering surgery effect in excessive scarring. The procedure was accompanied by toxic corneal endothelium decompensation with corneal edema and Descemet’s membrane folds treated with active metabolic therapy.

  1. Incidence of bleb-associated endophthalmitis in the United States

    Directory of Open Access Journals (Sweden)

    Vaziri K

    2015-02-01

    Full Text Available Kamyar Vaziri,1 Krishna Kishor,1 Stephen G Schwartz,1 Arindel S Maharaj,1 Darius M Moshfeghi,2 Andrew A Moshfeghi,3 Harry W Flynn Jr1 1Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, USA; 2Department of Ophthalmology, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA; 3USC Eye Institute, Department of Ophthalmology, University of Southern California Keck School of Medicine, Los Angeles, CA, USA Purpose: To evaluate the 5-year incidence rate of blebitis and bleb-associated endophthalmitis in the United States. Methods: In this retrospective cross-sectional study, we utilized a large commercial health insurance claim-based database during 2007–2011 and identified all patients who had a record of trabeculectomy in 2007. These patients were followed until the end of 2011. During the follow-up period, all incidences of blebitis, confirmed bleb-associated endophthalmitis, and presumed bleb-associated endophthalmitis were recorded. Kaplan–Meier survival analysis was utilized to calculate 5-year cumulative incidence rates of blebitis and bleb-associated endophthalmitis following trabeculectomy procedures. Results: Among the 1,461 trabeculectomies included in our analysis, eight cases of blebitis, five cases of confirmed bleb-associated endophthalmitis, and eight cases of presumed bleb-associated endophthalmitis were identified. We found that the 5-year cumulative incidence of blebitis was 0.55%±0.19%. The 5-year cumulative incidence of bleb-associated endophthalmitis was 0.45%±0.2% when only confirmed cases were included and 1.3%±0.34% when presumed cases were also added to the analysis. The mean time from procedure to diagnosis was 45 months for blebitis and 33 months for bleb-associated endophthalmitis. Conclusion: Blebitis and bleb-related endophthalmitis are uncommon in the United States. The 5-year cumulative incidence was 0.55% for blebitis

  2. Natural rubber: leather composites

    OpenAIRE

    Ravichandran, K.; 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 ...

  3. Cyanoacrylate tissue glue for wound repair in early posttrabeculectomy conjunctival bleb leak: a case series

    OpenAIRE

    Haslinda AR; Azhany Y; Noor-Khairul R; Zunaina E; Liza-Sharmini AT

    2015-01-01

    Abdul-Rahim Haslinda, Yaakub Azhany, Rasid Noor-Khairul, Embong Zunaina, Ahmad-Tajudin Liza-Sharmini Department of Ophthalmology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia Abstract: We demonstrated a noninvasive management of early bleb leak following trabeculectomy using cyanoacrylate tissue glue (CATG). Three patients who underwent augmented trabeculectomy with mitomycin C with early bleb leak between January 2009 and June 2010 ...

  4. Late-Onset Glaucoma-Filtrating Bleb Leak in a Penetrating Keratoplasty Patient: A Case Report

    OpenAIRE

    Zuleyha Yalniz-Akkaya; Ayse Burcu; Firdevs Ornek

    2012-01-01

    Introduction. Late-onset bleb leaks occur more frequently after the use of adjunctive antimetabolites and require surgical management to seal and preserve filtrating bleb. Case Presentation. A 48-year-old female presented with decreased visual acuity for five days in her left eye. She had a left penetrating keratoplasty one year earlier and two trabeculectomies 7 years earlier. Visual acuity was hand motions, intraocular pressure was 3 mmHg, corneal graft was clear, mature cataract was presen...

  5. 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...

  6. Influence of crumb rubber gradation on asphalt-rubber properties

    OpenAIRE

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

    2006-01-01

    Asphalt rubber is a material produced by the incorporation of crumb rubber obtained from ground tires in straight asphalt and its properties are influenced by the components properties. The crumb rubber gradation is one of the variables which have a significant influence on asphalt rubber properties. Thus, this work studies the influence of crumb rubber gradation on the asphalt rubber properties expressed by penetration, rotational viscosity (using the Brookfield viscometer), r...

  7. Office-based Slit-lamp Needle Revision with Adjunctive Mitomycin-C for Late Failed or Encapsulated Filtering Blebs

    OpenAIRE

    Heidar Amini; Alireza Esmaili; Reza Zarei; Nima Amini; Ramin Daneshvar

    2012-01-01

    Purpose: The purpose of this study was to assess the results of bleb needling in glaucomatous patients with late failed filtering blebs. Materials and Methods: A retrospective case series of 27 eyes of 27 patients was considered. All patients underwent needle bleb revision with adjuvant mitomycin-C performed at the slit lamp, during an office visit. Complete success was defined as postneedling intraocular pressure (IOP) ≤ 21 mmHg without any antiglaucoma medications and qualified success w...

  8. Soft Bandage Contact Lenses in Management of Early Bleb Leak Following Trabeculectomy

    Institute of Scientific and Technical Information of China (English)

    Zhenggen Wu; Chukai Huang; Yuqiang Huang; Wanqi Zhang; Di Ma

    2015-01-01

    Purpose:To investigate the efficacy of a soft bandage contact lens in the management of early bleb leak following tra-beculectomy. Methods: Between October 2011 and April 2013, 11 patients with early bleb leak following fornix-based trabeculectomy were instructed to wear a soft bandage contact lens 14 mm in diameter continuously for 1-2 weeks. The daily visual acuity, intraocular pressure (IOP), anterior chamber situation, and healing condition were measured at 1, 3, and 7 d, after con tact lens removal,.and 3 months after trabeculectomy..The con-ditions of blebs,.sensation of wearing contact lens,.and ad-verse events were recorded. Results:.Bleb leaks were observed at 2-8 d after surgery, (4.09±1.10 d on average). The daily LogMAR visual acuity did not significantly differ before and after contact lens wear (P>0.05). The IOP was significantly raised after at 1, 3, and 7 d after lens wear. (all P<0.05).The IOP at 3 months after lens wear did not significantly differ from that measured at lens removal (t=1.191, P=0.089). At 1 d after lens wear, 6 cases had deeper anterior chambers..All patients presented with a significantly deepened anterior chamber at 3 d after lens wear,.and were restored to the preoperative conditions..The bleb leakage was successfully treated at 7 d after lens removal in 10 patients, while 1 patient had to wear the contact lens for another 7 d for full healing of the bleb leak. No ocular infec-tion was noted throughout the management. Conclusion: A soft bandage contact lens of 14 mm diameter is a safe and efficacious therapy for an early bleb leak fol-lowing fornix-based trabeculectomy.

  9. Natural rubber: leather composites

    Directory of Open Access Journals (Sweden)

    K. Ravichandran

    2005-06-01

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

  10. Magnetic rubber inspection (MRI)

    International Nuclear Information System (INIS)

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

  11. Cyanoacrylate tissue glue for wound repair in early posttrabeculectomy conjunctival bleb leak: a case series

    Directory of Open Access Journals (Sweden)

    Haslinda AR

    2015-07-01

    Full Text Available Abdul-Rahim Haslinda, Yaakub Azhany, Rasid Noor-Khairul, Embong Zunaina, Ahmad-Tajudin Liza-Sharmini Department of Ophthalmology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia Abstract: We demonstrated a noninvasive management of early bleb leak following trabeculectomy using cyanoacrylate tissue glue (CATG. Three patients who underwent augmented trabeculectomy with mitomycin C with early bleb leak between January 2009 and June 2010 were reviewed. Case 1 and Case 2 exhibited bleb leak on postoperative Day 1 and Case 3 showed leak on follow-up at postoperative Day 7. Case 1 was successfully sealed with CATG at postoperative Day 3, after failed pressure padding and bandage contact lens. Case 2 was successfully sealed with CATG at postoperative Day 3, after failed pressure padding and conjunctiva flap resuturing. In Case 3, the leaking conjunctival flap was managed with combined techniques of resuturing and applying CATG at postoperative Day 9, after failed pressure padding. During leakage, the intraocular pressure was low (6–8 mmHg in all three cases, with shallow anterior chamber depth and absence of other complications such as choroidal detachment, hypotony maculopathy, or endophthalmitis. Foreign body sensation was the main complaint following the procedure. No clinical allergy reaction was documented. CATG may serve as a potential adjunctive and effective method in the management of posttrabeculectomy early bleb leak. Keywords: cyanoacrylate tissue glue, bleb leak, trabeculectomy, mitomycin C

  12. Late-Onset Glaucoma-Filtrating Bleb Leak in a Penetrating Keratoplasty Patient: A Case Report

    Directory of Open Access Journals (Sweden)

    Zuleyha Yalniz-Akkaya

    2012-01-01

    Full Text Available Introduction. Late-onset bleb leaks occur more frequently after the use of adjunctive antimetabolites and require surgical management to seal and preserve filtrating bleb. Case Presentation. A 48-year-old female presented with decreased visual acuity for five days in her left eye. She had a left penetrating keratoplasty one year earlier and two trabeculectomies 7 years earlier. Visual acuity was hand motions, intraocular pressure was 3 mmHg, corneal graft was clear, mature cataract was present, and axial length was 30.48 mm. The conjunctiva covering the superotemporal sclerotomy was avascular, flat, and partially lost. After heavily painting the bleb with a fluorescein, late-onset point leak was revealed. Overlying conjunctiva was excised. The atrophic, irregular, and partially absent scleral flap was covered by a processed human pericardium graft and conjunctival advancement. Postoperatively, intraocular pressure stabilized around 16 mmHg. After four months, phacoemulsification and intraocular lens implantation were performed. Visual acuity did not exceed 0.1 (in decimal notation due to degenerative myopia-related macular atrophy. Corneal graft remained clear at her 6-month followup period. Conclusion. Surgical bleb revision using a pericardium graft and conjunctival advancement seems to be an effective method for treating late bleb leaks. However, careful follow-up is required for detecting recurrent leaks and elevated intraocular pressure.

  13. Postpartum Blues

    Medline Plus

    Full Text Available ... blues The postpartum blues E-mail to a friend Please fill in all fields. Please enter a ... blues: Talk to your partner or a good friend about how you feel Get plenty of rest ...

  14. Application of 2-octyl-cyanoacrylate for corneal perforation and glaucoma filtering bleb leak

    Directory of Open Access Journals (Sweden)

    Okabe M

    2013-03-01

    Full Text Available Motonori Okabe,1 Kiyotaka Kitagawa,2 Toshiko Yoshida,1 Chika Koike,1 Takeshi Katsumoto,2 Etsuko Fujihara,2 Toshio Nikaido1 1Department of Regenerative Medicine, University of Toyama, Graduate School of Medicine and Pharmaceutical Sciences, Toyama, 2Division of Ophthalmology, Matsue Red Cross Hospital, Japanese Red Cross Society, Shimane, Japan Background: This paper reports on the efficacy of a tissue adhesive, 2-octyl-cyanoacrylate, in the treatment of corneal perforation and glaucoma filtering bleb leak. Methods: Two eyes from two patients with corneal perforation or laceration and two eyes from two patients with bleb leak were included. The patients underwent application of 2-octyl-cyanoacrylate onto the perforated or leaking site, and a hydrogel contact lens was applied as a bandage. We also evaluated the in vitro cell toxicity of 2-octyl-cyanoacrylate in HeLa cells. Results: The two cases of corneal perforation were repaired within 22 days with one application of the tissue adhesive. The two cases of bleb leak were repaired with 2–4 applications of the tissue adhesive over 134 (range 17–134 days. There were no recurrences or adverse effects during a mean follow-up period of 12.7 months. In vitro testing revealed that 2-octyl-cyanoacrylate was markedly toxic to HeLa cells. Conclusion: Four patients with corneal perforation or bleb leak were successfully managed using 2-octyl-cyanoacrylate tissue adhesive. This simple and easy surgical technique may become an alternative therapeutic option for corneal perforation or bleb leak, although several applications of this tissue adhesive may be required. Although 2-octyl-cyanoacrylate was toxic to HeLa cells, no adverse clinical effects were noted using this adhesive. Keywords: corneal perforation, bleb leak, tissue adhesive, 2-octyl-cyanoacrylate

  15. Filtering bleb activation in the early post-operative period after fistulizing surgery

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2014-10-01

    Full Text Available The article presents a case report of a patient with a cystic bleb in the early postoperative period after trabeculectomy. Patient complained of discomfort in a recently (4 weeks operated eye. Medical regimen administered previously had been taken irregularly. Biomicroscopy revealed a high, encapsulated cystic bleb with thin walls and hyperemia. Intraocular pressure at the moment of examination was 27 mmHg. Local hypotensive therapy had been neglected by the patient. A local anti-inflammatory (tobramycin / dexamethasone fixed combination and hypotensive (brimonidine / timolol fixed combination therapy was administered. 24 hours later, when intraocular pressure decreased to 20 mmHg, a needle revision procedure was conducted for partial bleb wall destruction and subconjunctival injection of dexamethasone, fluorouracil and ranibizumab. During the next day examination the bleb was diffuse, with less hyperemia and an abundance of conjunctival microcysts in the central bleb’s zone. Intraocular pressure was 10.2 mmHg. No choroidal detachment was noted during ophthalmoscopy and OCT examination. The patient continued anti-inflammatory therapy. Another needling procedure with the same drug combination was repeated two weeks after due to an increased hyperemia. At the end of the four-week follow-up period the filtering bleb remained diffuse and the intraocular pressure was 13.2 mmHg. Dexamethasone drops were prescribed to be instilled 1‑2 times a day for a month. This case report demonstrates the method of restoring a functioning filtering bleb by the needle revision with antiinflammatory, cytostatic and anti-VEGF therapy for prolonging the hypotensive effect of a trabeculectomy in the presence of wound healing.

  16. Failure studies on rubber and rubber composites

    Science.gov (United States)

    Tao, Zhenghong

    A research study has been conducted to investigate selected failure processes in rubber and rubbery composites. Specific failure modes and materials considered included mechanical tearing of rubber-coated fabrics and mechanical/thermal fatigue of carbon black-filled elastomers. Experimental efforts developed novel evaluation techniques that were used to access failure resistance of the materials, as well as to elucidate molecular structure/physical properties relationships. Results are presented in multi-monograph format consisting of a series of four interdependent papers published in peer-reviewed journals. The first monograph measures the tear resistance of a series of polyester fabrics, of controlled fill-yarn size, coated with a compounded butyl rubber resin. A constrained trouser tear test is used to quantify the role of yarn mobility on crack-tip development and the resultant tear strength. As the area around a propagating crack is constrained, tear strength decreases by several orders of magnitude, indicating that the ability of the composite structure to dissipate energy away from the crack tip contributes more to tear resistance than the intrinsic strength of the concomitant materials. Monograph number two continues the work of the first by developing a novel cutting technique to monitor the role of the fiber/rubber interphase during tear propagation. This approach was applied to five different elastomers coated onto one of the polyester yarns. These data show a threefold increase in strength is possible by proper optimization of the fiber/rubber bond. In the third monograph, five different rubber bushing compounds were evaluated for mechanical/thermal fatigue resistance. Samples were dynamically excited in combined compression and shear loadings using a specially designed test fixture. Results indicated that heat build-up was a major contributing factor to the eventual failure of the materials via a complex fracture mechanism, with epoxidized natural

  17. Lung ultrasound: a valid help in the differential diagnosis between pneumothorax and pulmonary blebs

    Directory of Open Access Journals (Sweden)

    Francesca Sandionigi

    2013-06-01

    Full Text Available Spontaneous pneumothorax is a relatively common disease but its radiological diagnosis can be difficult because of the insufficient sensitivity of chest X-rays. This is even more so when bullous emphysema and acute pneumothorax co-exist. There is evidence that lung ultrasound is a valid instrument to detect a pneumothorax and a valid help in the differential diagnosis between pneumothorax and pulmonary blebs. We present a case which suggests the potential superiority of lung ultrasound on chest radiography in distinguishing free air (pneumothorax from apical blebs, particularly when these are located in the posterior regions and may be easily confused with pneumothorax.

  18. Filtering bleb activation in the early post-operative period after fistulizing surgery

    OpenAIRE

    S. Yu. Petrov; Antonov, A. A.; S. V. Vostrukhin; L. A. Panyushkina; D. M. Safonova

    2014-01-01

    The article presents a case report of a patient with a cystic bleb in the early postoperative period after trabeculectomy. Patient complained of discomfort in a recently (4 weeks) operated eye. Medical regimen administered previously had been taken irregularly. Biomicroscopy revealed a high, encapsulated cystic bleb with thin walls and hyperemia. Intraocular pressure at the moment of examination was 27 mmHg. Local hypotensive therapy had been neglected by the patient. A local anti-inflammator...

  19. Radiation vulcanization of rubbers

    International Nuclear Information System (INIS)

    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.)

  20. US rubber markets recover

    International Nuclear Information System (INIS)

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

  1. Performance of asphalt rubber mixtures

    OpenAIRE

    Thives, Liseane Padilha; Trichês, Glicério; Pereira, Paulo A. A.; Pais, Jorge C.

    2010-01-01

    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: terminal blending (produced at industrial plants) and continuous blending (produced in asphalt plants). This study presents a laboratory evaluation of asphalt rubber mixtures produced with d...

  2. TRAIL promotes membrane blebbing, detachment and migration of cells displaying a dysfunctional intrinsic pathway of apoptosis

    Czech Academy of Sciences Publication Activity Database

    Somasekharan, S.P.; Koc, Michal; Morizot, A.; Micheau, O.; Sorensen, P.H.B.; Gaide, O.; Anděra, Ladislav; Martinou, J.C.

    2013-01-01

    Roč. 18, č. 3 (2013), s. 324-336. ISSN 1360-8185 Institutional support: RVO:68378050 Keywords : TRAIL * membrane blebbing * ROCK1 * HCT116 Bax−/− * cancer cell migration * drug resistance * bortezomib * proteasome Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.614, year: 2013

  3. Thoracoscopic CO laser coagulation shrinkage of blebs in treatment of spontaneous pneumothorax

    Science.gov (United States)

    Sensaki, Koji; Arai, Tsunenori; Kikuchi, Keiichi; Takagi, Keigo; Tanaka, Susumu; Kikuchi, Makoto

    1992-06-01

    Spontaneous pneumothorax is a common disease in young people. Operative intervention has been done in most of the recurrent cases. Recently thoracoscopic treatment has been tested as a less invasive treatment modarity. We adopted carbon monoxide (CO) laser for thoracoscopic treatment of recurrent spontaneous pneumothorax. CO laser (wavelength; 5.4 micrometers ) could be delivered by chalcogenide glass (As - S) covered with a teflon sheath and ZnSe fiber tip. The sterilized flexible bronchoscope was inserted through the thoracoscopic outer sheath under local anesthesia. Shrinkage of blebs was obtained by non-contact method of CO laser irradiation. Laser power at the tip was 2.5 - 5 W and irradiation duration was 0.5 s each. Excellent shrinkage of bleb and bulla could be obtained by CO laser without perforation complication. Advantages of CO laser as a thoracoscopic treatment were: (1) capability of fiber delivery (flexible thoracoscopy was easy to operate and clear to visualize the blebs which were frequently found at the apical portion of the lung, and (2) shallow extinction length (good shrinkage of blebs, low risk of perforation, and thin layer of carbonization). In conclusion, our new technique of thoracoscopic CO laser irradiation was found to be a safe and effective treatment of spontaneous pneumothorax.

  4. Membrane Protein Mobility and Orientation Preserved in Supported Bilayers Created Directly from Cell Plasma Membrane Blebs.

    Science.gov (United States)

    Richards, Mark J; Hsia, Chih-Yun; Singh, Rohit R; Haider, Huma; Kumpf, Julia; Kawate, Toshimitsu; Daniel, Susan

    2016-03-29

    Membrane protein interactions with lipids are crucial for their native biological behavior, yet traditional characterization methods are often carried out on purified protein in the absence of lipids. We present a simple method to transfer membrane proteins expressed in mammalian cells to an assay-friendly, cushioned, supported lipid bilayer platform using cell blebs as an intermediate. Cell blebs, expressing either GPI-linked yellow fluorescent proteins or neon-green fused transmembrane P2X2 receptors, were induced to rupture on glass surfaces using PEGylated lipid vesicles, which resulted in planar supported membranes with over 50% mobility for multipass transmembrane proteins and over 90% for GPI-linked proteins. Fluorescent proteins were tracked, and their diffusion in supported bilayers characterized, using single molecule tracking and moment scaling spectrum (MSS) analysis. Diffusion was characterized for individual proteins as either free or confined, revealing details of the local lipid membrane heterogeneity surrounding the protein. A particularly useful result of our bilayer formation process is the protein orientation in the supported planar bilayer. For both the GPI-linked and transmembrane proteins used here, an enzymatic assay revealed that protein orientation in the planar bilayer results in the extracellular domains facing toward the bulk, and that the dominant mode of bleb rupture is via the "parachute" mechanism. Mobility, orientation, and preservation of the native lipid environment of the proteins using cell blebs offers advantages over proteoliposome reconstitution or disrupted cell membrane preparations, which necessarily result in significant scrambling of protein orientation and typically immobilized membrane proteins in SLBs. The bleb-based bilayer platform presented here is an important step toward integrating membrane proteomic studies on chip, especially for future studies aimed at understanding fundamental effects of lipid interactions

  5. Generation of micronuclei during interphase by coupling between cytoplasmic membrane blebbing and nuclear budding.

    Directory of Open Access Journals (Sweden)

    Koh-ichi Utani

    Full Text Available Micronucleation, mediated by interphase nuclear budding, has been repeatedly suggested, but the process is still enigmatic. In the present study, we confirmed the previous observation that there are lamin B1-negative micronuclei in addition to the positive ones. A large cytoplasmic bleb was found to frequently entrap lamin B1-negative micronuclei, which were connected to the nucleus by a thin chromatin stalk. At the bottom of the stalk, the nuclear lamin B1 structure appeared broken. Chromatin extrusion through lamina breaks has been referred to as herniation or a blister of the nucleus, and has been observed after the expression of viral proteins. A cell line in which extrachromosomal double minutes and lamin B1 protein were simultaneously visualized in different colors in live cells was established. By using these cells, time-lapse microscopy revealed that cytoplasmic membrane blebbing occurred simultaneously with the extrusion of nuclear content, which generated lamin B1-negative micronuclei during interphase. Furthermore, activation of cytoplasmic membrane blebbing by the addition of fresh serum or camptothecin induced nuclear budding within 1 to 10 minutes, which suggested that blebbing might be the cause of the budding. After the induction of blebbing, the frequency of lamin-negative micronuclei increased. The budding was most frequent during S phase and more efficiently entrapped small extrachromosomal chromatin than the large chromosome arm. Based on these results, we suggest a novel mechanism in which cytoplasmic membrane dynamics pulls the chromatin out of the nucleus through the lamina break. Evidence for such a mechanism was obtained in certain cancer cell lines including human COLO 320 and HeLa. The mechanism could significantly perturb the genome and influence cancer cell phenotypes.

  6. Postpartum Blues

    Medline Plus

    Full Text Available ... Quality Collaboratives Launch Prematurity research centers What is team science? More than 75 years of solving problems ... delivery cause the postpartum blues. How can you manage the baby blues? The American College of Obstetricians ...

  7. Postpartum Blues

    Medline Plus

    Full Text Available ... with this condition are happy most of the time. But compared to how she usually feels, the ... the "blues" usually lessens and goes away over time. What causes the baby blues? Medical experts believe ...

  8. Postpartum Blues

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    Full Text Available ... Postpartum care > The postpartum blues The postpartum blues E-mail to a friend Please fill in all fields. Please enter a valid e-mail address. Your information: Your recipient's information: Your ...

  9. Postpartum Blues

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    Full Text Available ... usually lessens and goes away over time. What causes the baby blues? Medical experts believe that changes ... usually lessens and goes away over time. What causes the baby blues? Medical experts believe that changes ...

  10. Postpartum Blues

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    Full Text Available ... Feels sad Feels confused The postpartum blues peak three to five days after delivery. They usually end ... Feels sad Feels confused The postpartum blues peak three to five days after delivery. They usually end ...

  11. Postpartum Blues

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    Full Text Available ... postpartum blues Now playing: E-mail to a friend Please fill in all fields. Please enter a ... blues: Talk to your partner or a good friend about how you feel Get plenty of rest ...

  12. Postpartum Blues

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    Full Text Available ... The postpartum blues The postpartum blues Now playing: E-mail to a friend Please fill in all fields. Please enter a valid e-mail address. Your information: Your recipient's information: Your ...

  13. Postpartum Blues

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    Full Text Available ... of Obstetricians and Gynecologists recommends that women do these things to help relieve the baby blues: Talk ... of Obstetricians and Gynecologists recommends that women do these things to help relieve the baby blues: Talk ...

  14. Postpartum Blues

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    Full Text Available ... Medical experts believe that changes in the woman's hormones after delivery cause the postpartum blues. How can ... Medical experts believe that changes in the woman's hormones after delivery cause the postpartum blues. How can ...

  15. Postpartum Blues

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    Full Text Available ... can you manage the baby blues? The American College of Obstetricians and Gynecologists recommends that women do ... can you manage the baby blues? The American College of Obstetricians and Gynecologists recommends that women do ...

  16. Postpartum Blues

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    Full Text Available ... postpartum blues The postpartum blues E-mail to a friend Please fill in all fields. Please enter ... hear about breakthroughs for babies and families. Ask a question Our health experts can answer questions about ...

  17. Postpartum Blues

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    Full Text Available ... us on Twitter Instagram: behind the scenes Our research Research grants Prematurity research Birth defects research Infant ... postpartum blues are not pleasant, the woman can function normally. The feeling of the "blues" usually lessens ...

  18. Electron beam processing of rubbers

    International Nuclear Information System (INIS)

    At present, the country producing natural rubber most is Malaysia, but the future share of natural rubber production of Malaysia is likely to decrease, while the share of Indonesia is expected to increase because the area of rubber plantation is increasing. Indonesia exports natural rubber as a raw material, and imports natural rubber products such as tires, belts and surgical gloves. Indonesia would obtain more foreign currency if it could export rubber products, and the future success in the export of rubber products is dependent on the development of new rubber technology. In this connection, two electron beam processings of rubbers are discussed in this paper, that is, tire production and the radiation vulcanization of natural rubber latex. Both processings are deeply related to the cross-linking of rubbers. The physical properties of natural rubber change by cross-linking, namely, the solvent resistance, tensile strength and hardness increase, and the elongation at breaking down decreases. About ten medium energy electron beam machines are used for tire production in Japan. The merits of radiation vulcanized natural rubber latex are shown. Its industrial application is explained. (K.I.)

  19. Theory of powdery rubber wear

    Science.gov (United States)

    Persson, B. N. J.

    2009-12-01

    Rubber wear typically involves the removal of small rubber particles from the rubber surface. On surfaces with not too sharp roughness, e.g. most road surfaces, this involves (slow) crack propagation. In this paper I shall present a theory of mild rubber wear. I shall derive the distribution of wear particle sizes Φ(D), which is in excellent agreement with experiment. I shall also show that the calculated wear rate is consistent with experimental data for tire tread block wear.

  20. Theory of powdery rubber wear

    International Nuclear Information System (INIS)

    Rubber wear typically involves the removal of small rubber particles from the rubber surface. On surfaces with not too sharp roughness, e.g. most road surfaces, this involves (slow) crack propagation. In this paper I shall present a theory of mild rubber wear. I shall derive the distribution of wear particle sizes Φ(D), which is in excellent agreement with experiment. I shall also show that the calculated wear rate is consistent with experimental data for tire tread block wear.

  1. Qualitative theory of rubber friction

    OpenAIRE

    Persson, B.N.J.; E. Tosatti

    2000-01-01

    When rubber is slid on a hard, rough substrate, the surface asperities of the substrate exert oscillating forces on the rubber surface leading to energy "dissipation" via the internal friction of the rubber. We present a qualitative discussion of how the resulting friction force depends on the nature of the surface roughness and comment on the origin of the wear of sliding rubber surfaces. (C) 2000 American Institute of Physics. [S0021-9606(00)51404-4].

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

    OpenAIRE

    Asrul M.; Othman M.; Zakaria M; Ahmad-Nazir K.

    2014-01-01

    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 ...

  3. Pneumoconiosis in rubber workers

    International Nuclear Information System (INIS)

    Radiographic survey carried out on rubber workers revealed that 32 % (24/76) of the workers showed pneumoconiosis. The cases of pneumoconiosis were found in workers who had been exposed to dust for more than 10 years. Among the 24 cases of pneumoconiosis, 15 workers had been exposed to talc dust for more than 12 years. Chest radiographs of the rubber workers who had been exposed to dust for more than 10 years demonstrated radiographic findings and incidences as follows; nodular pattern (16 %), fine reticular and granular pattern (52 %), reticular pattern (36 %), irregularity of lung markings (61 %), ground-glass appearance (8 %), and pleural thickening (15 %). Irregular opacities such as fine reticular and granular pattern, reticular pattern and irregularity of lung markings seen to be major radiographic findings of pneumoconiosis of the rubber workers. While, nodular pattern seen in upper and middle lung zones and pleural thickening seen in apices and upper lung zones seen to be minor changes. (author)

  4. Rubber molds for investment casting

    International Nuclear Information System (INIS)

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

  5. Office-based Slit-lamp Needle Revision with Adjunctive Mitomycin-C for Late Failed or Encapsulated Filtering Blebs

    Science.gov (United States)

    Amini, Heidar; Esmaili, Alireza; Zarei, Reza; Amini, Nima; Daneshvar, Ramin

    2012-01-01

    Purpose: The purpose of this study was to assess the results of bleb needling in glaucomatous patients with late failed filtering blebs. Materials and Methods: A retrospective case series of 27 eyes of 27 patients was considered. All patients underwent needle bleb revision with adjuvant mitomycin-C performed at the slit lamp, during an office visit. Complete success was defined as postneedling intraocular pressure (IOP) ≤ 21 mmHg without any antiglaucoma medications and qualified success was IOP ≤ 21 mmHg with topical antiglaucoma medications. Results: There were 12 eyes with encapsulated blebs and 15 eyes with flat blebs. The mean interval between index filtering surgery and bleb revision was 32.74 ± 15.36 months. Mean IOP was 25.07 ± 4.80 mmHg before surgery and 19.66 ± 4.97 mmHg at last postoperative follow-up. The mean follow-up was 20.31 ± 15.63 months. Complete and qualified successes were 7.4% and 51.9%, respectively. Cumulative rates of success at 1, 2, 3, and 4 years were 76%, 65%, 49%, and 37%, respectively. The mean number of antiglaucoma medications was reduced from 3.15 ± 0.36 preoperatively to 2.33 ± 1.21 postoperatively (P<0.001). Conclusion: Slit-lamp needle revision in office is a simple and effective method for treating late encapsulated or flat filtering blebs without significant complications even for late bleb failure. PMID:22623862

  6. Lung ultrasound: a valid help in the differential diagnosis between pneumothorax and pulmonary blebs

    OpenAIRE

    Francesca Sandionigi; Francesca Cortellaro; Elisa Forni; Daniele Coen

    2013-01-01

    Spontaneous pneumothorax is a relatively common disease but its radiological diagnosis can be difficult because of the insufficient sensitivity of chest X-rays. This is even more so when bullous emphysema and acute pneumothorax co-exist. There is evidence that lung ultrasound is a valid instrument to detect a pneumothorax and a valid help in the differential diagnosis between pneumothorax and pulmonary blebs. We present a case which suggests the potential superiority of lung ultrasound on che...

  7. Endovascular coil embolization of aneurysm neck for the treatment of ruptured intracranial aneurysm with bleb formation

    OpenAIRE

    Wan, Jun; Gu, Weijin; Zhang, Xiaolong; Geng, Daoying; Lu, Gang; Huang, Lei; Zhang, Lei; Ge, Liang; Ji, Lihua

    2014-01-01

    Background Ruptured intracranial aneurysm (ICA) with bleb formation (RICABF) is a special type of ruptured ICA. However, the exact role and effectiveness of endovascular coil embolization (ECE) in RICABF is unknown. We aimed to investigate the effectiveness and safety of ECE of aneurysm neck for RICABF treatment. Material/Methods We retrospectively assessed consecutive patients who were hospitalized in our endovascular intervention center between October 2004 and May 2012. Overall, 86 patient...

  8. Good functional recovery following intervention for delayed suprachoroidal haemorrhage post bleb needling: a case report

    Directory of Open Access Journals (Sweden)

    Cannon Paul S

    2008-03-01

    Full Text Available Abstract Introduction Bleb needling is a recognised procedure in the management of patients with failing trabeculectomies. Suprachoroidal haemorrhage can occur as an unusual complication. We report a pseudophakic man who had early surgical intervention for this complication. This intervention may have contributed to the good recovery of his visual acuity and the minimum changes to his visual fields. Case presentation A 79-year-old pseudophakic man with chronic open angle glaucoma presented with further deterioration of his right visual field despite maximum medical therapy and a previous trabeculectomy. The right visual acuity was 6/9 with an intraocular pressure (IOP of 16 mmHg. Bleb needling with 5-fluouracil was performed in a standard manner. His postoperative IOP was 6 mmHg. Thirty-six hours later the visual acuity was reduced to hand movements and two large choroidal detachments where observed clinically, which progressed to suprachoroidal haemorrhages. Five days after the initial needling, the patient had complex surgery involving anterior chamber reformation, a bleb compression suture and drainage of the haemorrhagic suprachoroidal detachments. Subsequently, the patient had a right vitrectomy with endolaser following a vitreous haemorrhage. The final visual acuity was 6/9 with an intraocular pressure of 8 mmHg on travoprost and brinzolamide. The final visual field showed little change when compared with the pre-suprachoroidal haemorrhage visual field. Conclusion It is important to consider the possibility of delayed suprachoroidal haemorrhage as a complication in bleb needling, and early surgical intervention may be beneficial.

  9. Good functional recovery following intervention for delayed suprachoroidal haemorrhage post bleb needling: a case report

    OpenAIRE

    Cannon Paul S; Spencer A; Lavin Michael

    2008-01-01

    Abstract Introduction Bleb needling is a recognised procedure in the management of patients with failing trabeculectomies. Suprachoroidal haemorrhage can occur as an unusual complication. We report a pseudophakic man who had early surgical intervention for this complication. This intervention may have contributed to the good recovery of his visual acuity and the minimum changes to his visual fields. Case presentation A 79-year-old pseudophakic man with chronic open angle glaucoma presented wi...

  10. Management of the late leaking filtration blebs. A report of seven cases and a selective review of the literature.

    Directory of Open Access Journals (Sweden)

    Mandal A

    2001-01-01

    Full Text Available PURPOSE: To describe the outcome of various treatment modalities in the management of late bleb leaks after glaucoma filtering surgery (GFS. MATERIALS AND METHODS: Seven consecutive patients treated for late bleb leaks (Seidel′s positive between July 1990 and June 1999 were were enrolled in the study. The management strategy consisted of initial conservative therapy, and tailored surgery, if necessary. The surgical technique employed was either conjunctival-Tenon′s advancement flap, hinged scleral flap, or fistulectomy with direct suturing. The main outcome measures were bleb characteristics and postoperative intraocular pressure (IOP. The secondary outcome measure was visual acuity. RESULTS: One patient responded to conservative therapy (aqueous suppressants, bandage contact lens and six patients needed surgery. The successful surgical technique was conjunctivo-Tenon′s advancement flap in three, hinged scleral flap in two, and fistulectomy-direct suturing to the wound (combined with cataract surgery and intraocular lens implantation in one patient. The bleb leak stopped in all cases and 5 of the 6 surgical patients sustained functioning filtering blebs. Follow-up ranged from 8 to 56 months (mean = 20.4 +/- 16.2 months. Visual acuity improved to 6/12 or better in 4 cases, 6/36 in 2 cases and it remained at light perception in one case. None of the patients had any intraoperative or postoperative complications. CONCLUSIONS: Late leaking blebs after GFS can be treated successfully. The management decision and selection of surgical technique should be based on the clinical condition.

  11. Water Swollen Natural Rubber

    Directory of Open Access Journals (Sweden)

    Sureurg KHONGTONG

    2008-01-01

    Full Text Available Modification of natural rubber by grafting of maleic anhydride yielded a water absorbable substrate. It was found that water contact angles of treated samples declined as the concentrations of maleic anhydride increased reflecting higher water compatibility in grafted samples. Submergence in water of these samples caused dramatic swelling with the water content up to about 60 wt %.

  12. Water Swollen Natural Rubber

    OpenAIRE

    Sureurg KHONGTONG; Narong FUNGCHONLAJIT

    2008-01-01

    Modification of natural rubber by grafting of maleic anhydride yielded a water absorbable substrate. It was found that water contact angles of treated samples declined as the concentrations of maleic anhydride increased reflecting higher water compatibility in grafted samples. Submergence in water of these samples caused dramatic swelling with the water content up to about 60 wt %.

  13. Etiology and epidemiological analysis of glaucoma-filtering bleb infections in a tertiary eye care hospital in south India

    Directory of Open Access Journals (Sweden)

    R Ramakrishnan

    2011-01-01

    Full Text Available Purpose : To evaluate the microbial etiology and associated risk factors among patients with blebitis following trabeculectomy. Materials and Methods : A retrospective analysis of all culture-proven blebitis was performed in patients who underwent trabeculectomy between January 2004 and December 2008. A standardized form was filled out for each patient, documenting sociodemographic features and information pertaining to risk factors. Swabbing of the infected bleb surface was performed for all suspected cases and further subjected to microbiological analysis. Results : A total of 23 patients with culture-proven blebitis were treated during the study period, with a mean age of 59.2 years (59.2 ± SD: 12.8; range, 30-81 years. Duration of onset was early (≤36 months in six (26% cases and late (> 36 months in 17 (74% cases with a range between 15 and 144 months (mean, 82.91 months; SD: 41.89. All 23 blebs were located superiorly and of which, 21 (91% were microcystic avascular, 1 (4% diffuse avascular, and 1 (4% vascular flattened. The predominant risk factor identified was bleb leak (35%; 8 of 23 followed by thin bleb (22%; 5 of 23 and blepharitis (17%; 4 of 23. Bleb leaks (100% were recorded only in patients with late onset (≥ 9 years of infection (P< 0.001, while the incidence of ocular surface disease (100% occurred early (≤3 years (P< 0.001. Use of topical steroids was associated frequently with cases of thin blebs (80%; 4 of 5 (P< 0.001, while topical antibiotics showed bleb leaks (88%; 7 of 8 (P< 0.001. Coagulase-positive staphylococci were frequently recovered from blebitis with thin blebs (71%; 5 of 7 (P = 0.001, Coagulase-negative staphylococci (CoNS with bleb leak (100%; 8 of 8 (P< 0.001, Corynebacterium with blepharitis (100%; 3 of 3 (P = 0.001, and Streptococci with releasable sutures (75%; 3 of 4 (P = 0.001. Conclusion : Bleb leak is the principal risk factor responsible for late-onset blebitis, while early-onset blebitis could

  14. Force spectroscopy measurements show that cortical neurons exposed to excitotoxic agonists stiffen before showing evidence of bleb damage.

    Science.gov (United States)

    Zou, Shan; Chisholm, Roderick; Tauskela, Joseph S; Mealing, Geoff A; Johnston, Linda J; Morris, Catherine E

    2013-01-01

    In ischemic and traumatic brain injury, hyperactivated glutamate (N-methyl-D-aspartic acid, NMDA) and sodium (Nav) channels trigger excitotoxic neuron death. Na(+), Ca(++) and H2O influx into affected neurons elicits swelling (increased cell volume) and pathological blebbing (disassociation of the plasma membrane's bilayer from its spectrin-actomyosin matrix). Though usually conflated in injured tissue, cell swelling and blebbing are distinct processes. Around an injury core, salvageable neurons could be mildly swollen without yet having suffered the bleb-type membrane damage that, by rendering channels leaky and pumps dysfunctional, exacerbates the excitotoxic positive feedback spiral. Recognizing when neuronal inflation signifies non-lethal osmotic swelling versus blebbing should further efforts to salvage injury-penumbra neurons. To assess whether the mechanical properties of osmotically-swollen versus excitotoxically-blebbing neurons might be cytomechanically distinguishable, we measured cortical neuron elasticity (gauged via atomic force microscopy (AFM)-based force spectroscopy) upon brief exposure to hypotonicity or to excitotoxic agonists (glutamate and Nav channel activators, NMDA and veratridine). Though unperturbed by solution exchange per se, elasticity increased abruptly with hypotonicity, with NMDA and with veratridine. Neurons then invariably softened towards or below the pre-treatment level, sometimes starting before the washout. The initial channel-mediated stiffening bespeaks an abrupt elevation of hydrostatic pressure linked to NMDA or Nav channel-mediated ion/H2O fluxes, together with increased [Ca(++)]int-mediated submembrane actomyosin contractility. The subsequent softening to below-control levels is consistent with the onset of a lethal level of bleb damage. These findings indicate that dissection/identification of molecular events during the excitotoxic transition from stiff/swollen to soft/blebbing is warranted and should be feasible. PMID

  15. Force spectroscopy measurements show that cortical neurons exposed to excitotoxic agonists stiffen before showing evidence of bleb damage.

    Directory of Open Access Journals (Sweden)

    Shan Zou

    Full Text Available In ischemic and traumatic brain injury, hyperactivated glutamate (N-methyl-D-aspartic acid, NMDA and sodium (Nav channels trigger excitotoxic neuron death. Na(+, Ca(++ and H2O influx into affected neurons elicits swelling (increased cell volume and pathological blebbing (disassociation of the plasma membrane's bilayer from its spectrin-actomyosin matrix. Though usually conflated in injured tissue, cell swelling and blebbing are distinct processes. Around an injury core, salvageable neurons could be mildly swollen without yet having suffered the bleb-type membrane damage that, by rendering channels leaky and pumps dysfunctional, exacerbates the excitotoxic positive feedback spiral. Recognizing when neuronal inflation signifies non-lethal osmotic swelling versus blebbing should further efforts to salvage injury-penumbra neurons. To assess whether the mechanical properties of osmotically-swollen versus excitotoxically-blebbing neurons might be cytomechanically distinguishable, we measured cortical neuron elasticity (gauged via atomic force microscopy (AFM-based force spectroscopy upon brief exposure to hypotonicity or to excitotoxic agonists (glutamate and Nav channel activators, NMDA and veratridine. Though unperturbed by solution exchange per se, elasticity increased abruptly with hypotonicity, with NMDA and with veratridine. Neurons then invariably softened towards or below the pre-treatment level, sometimes starting before the washout. The initial channel-mediated stiffening bespeaks an abrupt elevation of hydrostatic pressure linked to NMDA or Nav channel-mediated ion/H2O fluxes, together with increased [Ca(++]int-mediated submembrane actomyosin contractility. The subsequent softening to below-control levels is consistent with the onset of a lethal level of bleb damage. These findings indicate that dissection/identification of molecular events during the excitotoxic transition from stiff/swollen to soft/blebbing is warranted and should be

  16. Elastic instabilities in rubber

    Science.gov (United States)

    Gent, Alan

    2009-03-01

    Materials that undergo large elastic deformations can exhibit novel instabilities. Several examples are described: development of an aneurysm on inflating a rubber tube; non-uniform stretching on inflating a spherical balloon; formation of internal cracks in rubber blocks at a critical level of triaxial tension or when supersaturated with a dissolved gas; surface wrinkling of a block at a critical amount of compression; debonding or fracture of constrained films on swelling, and formation of ``knots'' on twisting stretched cylindrical rods. These various deformations are analyzed in terms of a simple strain energy function, using Rivlin's theory of large elastic deformations, and the results are compared with experimental measurements of the onset of unstable states. Such comparisons provide new tests of Rivlin's theory and, at least in principle, critical tests of proposed strain energy functions for rubber. Moreover the onset of highly non-uniform deformations has serious implications for the fatigue life and fracture resistance of rubber components. [4pt] References: [0pt] R. S. Rivlin, Philos. Trans. Roy. Soc. Lond. Ser. A241 (1948) 379--397. [0pt] A. Mallock, Proc. Roy. Soc. Lond. 49 (1890--1891) 458--463. [0pt] M. A. Biot, ``Mechanics of Incremental Deformations'', Wiley, New York, 1965. [0pt] A. N. Gent and P. B. Lindley, Proc. Roy. Soc. Lond. A 249 (1958) 195--205. [0pt] A. N. Gent, W. J. Hung and M. F. Tse, Rubb. Chem. Technol. 74 (2001) 89--99. [0pt] A. N. Gent, Internatl. J. Non-Linear Mech. 40 (2005) 165--175.

  17. Office-based slit-lamp needle revision with adjunctive Mitomycin-C for late failed or encapsulated filtering blebs

    Directory of Open Access Journals (Sweden)

    Heidar Amini

    2012-01-01

    Results: There were 12 eyes with encapsulated blebs and 15 eyes with flat blebs. The mean interval between index filtering surgery and bleb revision was 32.74 ± 15.36 months. Mean IOP was 25.07 ± 4.80 mmHg before surgery and 19.66 ± 4.97 mmHg at last postoperative follow-up. The mean follow-up was 20.31 ± 15.63 months. Complete and qualified successes were 7.4% and 51.9%, respectively. Cumulative rates of success at 1, 2, 3, and 4 years were 76%, 65%, 49%, and 37%, respectively. The mean number of antiglaucoma medications was reduced from 3.15 ± 0.36 preoperatively to 2.33 ± 1.21 postoperatively (P<0.001. Conclusion: Slit-lamp needle revision in office is a simple and effective method for treating late encapsulated or flat filtering blebs without significant complications even for late bleb failure.

  18. CHARACTERIZATION OF RUBBER DEGRADING ISOLATES

    Directory of Open Access Journals (Sweden)

    M. D. Chengalroyen

    2012-12-01

    Full Text Available Sixteen soil samples were screened for the presence of rubber degrading strains. Twenty-five strains displaying clear zone formation on latex agar plates were purified. Identification revealed that twenty three of these isolates were Streptomyces species, one Pseudonocardia species and one Methylibium species. The addition of carbon sources with the exception of tween 80 enhanced extracellular rubber biodegradation. Scanning electron microscopy revealed that the isolates were able to colonize and penetrate vulcanized glove rubber.

  19. 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.)

  20. QENS investigation of filled rubbers

    International Nuclear Information System (INIS)

    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.)

  1. 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.  ……

  2. 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.

  3. Postpartum Blues

    Medline Plus

    Full Text Available ... leader Partner Spotlight Become a partner World Prematurity Day Your support helps babies We are determined to ... confused The postpartum blues peak three to five days after delivery. They usually end by the tenth ...

  4. Postpartum Blues

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    Full Text Available ... Saving Just a moment, please. You've saved this page It's been added to your dashboard . After ... blues" is not really correct since women with this condition are happy most of the time. But ...

  5. Postpartum Blues

    Medline Plus

    Full Text Available ... dashboard . After the baby is born, many new mothers have the postpartum blues (also called the baby ... compared to how she usually feels, the new mother: Is more irritable Cries more easily Feels sad ...

  6. Postpartum Blues

    Medline Plus

    Full Text Available ... articles March of Dimes Premature Birth Report Card Grades Cities, Counties; Focuses on Racial and Ethnic Disparities ... baby blues: Talk to your partner or a good friend about how you feel Get plenty of ...

  7. Postpartum Blues

    Medline Plus

    Full Text Available ... leader Partner Spotlight Become a partner World Prematurity Day World Prematurity Your support helps babies We are ... confused The postpartum blues peak three to five days after delivery. They usually end by the tenth ...

  8. Postpartum Blues

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    Full Text Available ... for your baby Feeding your baby Common illnesses New parents Family health & safety Complications & Loss Pregnancy complications ... your dashboard . After the baby is born, many new mothers have the postpartum blues (also called the ...

  9. Laboratory optimization of continuous blend asphalt rubber

    OpenAIRE

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

    2008-01-01

    Asphalt rubber from wet process requires batching blending and reaction time associated to blending rubber and conventional asphalt to produce asphalt rubber. The ideal blending of these materials depends on the combination of very important variables, such as the amount of rubber, reaction time and temperature reaction. This paper intends to optimize the laboratory production of asphalt rubber using the continuous blend process. The rubber from waste tyres was reduced by ambient grinding and...

  10. 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...

  11. Study on the properties of blend rubber prepared with grafted rubber and irradiated rubber by Gamma Rays

    International Nuclear Information System (INIS)

    The blend rubbers were prepared by mixing γ-rays irradiated and monomer grafted rubbers. The monomers, methyl methacrylate (MMA) and styrene were used separately to prepare grafted rubber by exposure to radiation. The physico-chemical properties of the blend rubbers were evaluated. The tensile strength and elongation at break of the blend rubbers decrease whereas modulus at 500% elongation, swelling ratio and permanent set increase with the increased proportion of grafted rubber in the blend. The tear strength of the blend between irradiated and styrene grafted rubbers increases with the increased proportion of grafted rubber but that of the blend of irradiated and MMA grafted rubbers remains almost constant. The blend rubber could be used for special type of application like rubber thread, tube, catheter etc

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

    OpenAIRE

    Velu CHANDRAN; Thomas MANVEL RAJ; Thangavelu LAKSHMANAN

    2016-01-01

    Application of scrap rubber and worn out tires in natural rubber compounds has been studied. The scrap rubber can, however, be recycled and compounded with natural rubber and thus can be generated as a rubber composite. In this work, recycled rubber particles (RRP) were prepared using pulverization process. Then, RRP was blended with natural rubber and silica compounds, and it was synthesized by two- roll mill and hydraulic press at specified operating conditions. The samples ranging from 0 t...

  13. Blood flow drives lumen formation by inverse membrane blebbing during angiogenesis in vivo.

    Science.gov (United States)

    Gebala, Véronique; Collins, Russell; Geudens, Ilse; Phng, Li-Kun; Gerhardt, Holger

    2016-04-01

    How vascular tubes build, maintain and adapt continuously perfused lumens to meet local metabolic needs remains poorly understood. Recent studies showed that blood flow itself plays a critical role in the remodelling of vascular networks, and suggested it is also required for the lumenization of new vascular connections. However, it is still unknown how haemodynamic forces contribute to the formation of new vascular lumens during blood vessel morphogenesis. Here we report that blood flow drives lumen expansion during sprouting angiogenesis in vivo by inducing spherical deformations of the apical membrane of endothelial cells, in a process that we have termed inverse blebbing. We show that endothelial cells react to these membrane intrusions by local and transient recruitment and contraction of actomyosin, and that this mechanism is required for single, unidirectional lumen expansion in angiogenic sprouts. Our work identifies inverse membrane blebbing as a cellular response to high external pressure. We show that in the case of blood vessels such membrane dynamics can drive local cell shape changes required for global tissue morphogenesis, shedding light on a pressure-driven mechanism of lumen formation in vertebrates. PMID:26928868

  14. Case of late-onset bleb associated endophthalmitis caused by Rothia mucilaginosa.

    Science.gov (United States)

    Oie, Shinya; Mochizuki, Kiyofumi; Ishida, Kyoko; Nakayama, Asami; Ohkusu, Kiyofumi

    2016-09-01

    Rothia mucilaginosa is a gram-positive coagulase-negative coccus of the family Micrococcaceae. Although R. mucilaginosa forms part of the oropharyngeal microflora, it has only recently been isolated in ocular infections. We report a case of a 41-year-old man who developed late-onset bleb-related endophthalmitis (BRE). He had undergone glaucoma surgery 21 years earlier and had a thin-walled cystic bleb prior to the development of endophthalmitis in his right eye. He immediately received intravitreal injections of ceftazidime and vancomycin, topical levofloxacin and cefmenoxime, and intravenous cefozopran. Culture of the aqueous humor specimen identified R. mucilaginosa by 16S rRNA sequence analysis. To our knowledge, this is the first report of late-onset BRE caused by R. mucilaginosa. Our case indicates that R. mucilaginosa can be a cause of late-onset BRE, and that molecular analysis is an accurate method to identify R. mucilaginosa. PMID:27008920

  15. Interaction of c-Cbl with myosin IIA regulates Bleb associated macropinocytosis of Kaposi's sarcoma-associated herpesvirus.

    Directory of Open Access Journals (Sweden)

    Mohanan Valiya Veettil

    Full Text Available KSHV is etiologically associated with Kaposi's sarcoma (KS, an angioproliferative endothelial cell malignancy. Macropinocytosis is the predominant mode of in vitro entry of KSHV into its natural target cells, human dermal microvascular endothelial (HMVEC-d cells. Although macropinocytosis is known to be a major route of entry for many viruses, the molecule(s involved in the recruitment and integration of signaling early during macropinosome formation is less well studied. Here we demonstrate that tyrosine phosphorylation of the adaptor protein c-Cbl is required for KSHV induced membrane blebbing and macropinocytosis. KSHV induced the tyrosine phosphorylation of c-Cbl as early as 1 min post-infection and was recruited to the sites of bleb formation. Infection also led to an increase in the interaction of c-Cbl with PI3-K p85 in a time dependent manner. c-Cbl shRNA decreased the formation of KSHV induced membrane blebs and macropinocytosis as well as virus entry. Immunoprecipitation of c-Cbl followed by mass spectrometry identified the interaction of c-Cbl with a novel molecular partner, non-muscle myosin heavy chain IIA (myosin IIA, in bleb associated macropinocytosis. Phosphorylated c-Cbl colocalized with phospho-myosin light chain II in the interior of blebs of infected cells and this interaction was abolished by c-Cbl shRNA. Studies with the myosin II inhibitor blebbistatin demonstrated that myosin IIA is a biologically significant component of the c-Cbl signaling pathway and c-Cbl plays a new role in the recruitment of myosin IIA to the blebs during KSHV infection. Myosin II associates with actin in KSHV induced blebs and the absence of actin and myosin ubiquitination in c-Cbl ShRNA cells suggested that c-Cbl is also responsible for the ubiquitination of these proteins in the infected cells. This is the first study demonstrating the role of c-Cbl in viral entry as well as macropinocytosis, and provides the evidence that a signaling complex

  16. 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.

  17. Rubber composition compatible with hydrazine

    Science.gov (United States)

    Repar, J.

    1973-01-01

    Formulation improves compatibility of butyl rubbers with hydrazine while reducing permeation to low levels necessary for prolonged storage in space. This is accomplished by replacing carbon-black filler with inert materials such as hydrated silica or clay. Pressure increases suggest that hydrazine is decomposed only slightly by new type of rubber.

  18. Blue gods, blue oil, and blue people.

    Science.gov (United States)

    Fairbanks, V F

    1994-09-01

    Studies of the composition of coal tar, which began in Prussia in 1834, profoundly affected the economies of Germany, Great Britain, India, and the rest of the world, as well as medicine and surgery. Such effects include the collapse of the profits of the British indigo monopoly, the growth in economic power of Germany based on coal tar chemistry, and an economic crisis in India that led to more humane tax laws and, ultimately, the independence of India and the end of the British Empire. Additional consequences were the development of antiseptic surgery and the synthesis of a wide variety of useful drugs that have eradicated infections and alleviated pain. Many of these drugs, particularly the commonly used analgesics, sulfonamides, sulfones, and local anesthetics, are derivatives of aniline, originally called "blue oil" or "kyanol." Some of these aniline derivatives, however, have also caused aplastic anemia, agranulocytosis, and methemoglobinemia (that is, "blue people"). Exposure to aniline drugs, particularly when two or three aniline drugs are taken concurrently, seems to be the commonest cause of methemoglobinemia today. PMID:8065194

  19. Postoperative Changes in Aqueous Monocyte Chemotactic Protein-1 Levels and Bleb Morphology after Trabeculectomy vs. Ex-PRESS Shunt Surgery.

    Directory of Open Access Journals (Sweden)

    Kohei Shobayashi

    Full Text Available To evaluate the postoperative changes in blebs and levels of aqueous monocyte chemotactic protein-1 (MCP-1 after trabeculectomy vs. Ex-PRESS tube shunt surgery.Rabbits were subjected to trabeculectomy or Ex-PRESS tube shunt surgery and observed for up to 3 months. Intraocular pressure (IOP was measured using a rebound tonometer. The MCP-1 level was measured by enzyme-linked immunosorbent assay (ELISA. Bleb morphology was evaluated using photos and anterior-segment optical coherence tomography (OCT.There were no differences in bleb appearance or IOP at any time between the groups. Bleb wall density in the anterior-segment OCT image was significantly lower 1 week after surgery in the Ex-PRESS group than the trabeculectomy group. The MCP-1 level in control eyes was 304.1 ± 45.2 pg/mL. In the trabeculectomy group, the mean aqueous MCP-1 level was 1444.9, 1914.3, 1899.8, 516.4, 398.3, 427.3, 609.5, 1612.7, 386.2, and 167.9 pg/mL at 3, 6, and 12 h, and 1, 2, 5, 7, 14, 30, and 90 days after surgery, respectively. In the Ex-PRESS group, the corresponding values were 1744.0, 1372.0, 932.5, 711.7, 396.1, 487.3, 799.5, 1327.9, 293.6, and 184.0 pg/mL. There were no significant differences in the aqueous MCP-1 level between the groups at any time point.The postoperative changes were similar in the Ex-PRESS and trabeculectomy groups, except for bleb wall density in the anterior-segment OCT image. The postoperative aqueous MCP-1 level had bimodal peaks in both groups.

  20. Blue Nile

    OpenAIRE

    Ramos, Manuel João

    2000-01-01

    The Blue Nile, whose source lies in highland Ethiopia, is known as “Al-Bahr al- Azraq” in Arabic, and as “Abbay” in Amharic. Along with the Atbara, it contributes more than 80 per cent of the Nile’s total water supply, the remainder coming mainly from the White Nile that stretches down to the Great Lakes plateau in Central Africa.

  1. The Cyclization of natural rubber

    International Nuclear Information System (INIS)

    The effect of solvent, temperature, time, weight percent of catalyst on the rate and mechanism of cyclization of natural rubber was studied in toluene and xylene solutions having tin tetra chloride catalyst (SnCl4). Iodo metric titration show, with 8% SnCl4 (based on polymer weight) cyclization occurs, leaving 27.4% of the total unsaturation. Infrared spectra of cyclized natural rubber show decreased absorption intensity at 840 and 780 cm-1 which are characteristic bands of the linear polymer and the appearance of absorption band at 890 cm-1 as cycles were formed. By using this chemical modification, natural rubber is transformed into a resinous thermoplastic, hard, non rubbery cyclized material with much less unsaturation than the original rubber, which could find commercial applications ad adhesives, printing inks, industrial and ship paints

  2. SILICONE RUBBER MOULDS FOR FOOTWEAR

    Directory of Open Access Journals (Sweden)

    Cornelia LUCA

    2013-05-01

    Full Text Available The leather confections industry uses the silicone rubber moulds for the symbols,notices and models stamping on the footwear or morocco goods parts. The paper presents somecontributions in this kind of devices manufacturing technology

  3. SILICONE RUBBER MOULDS FOR FOOTWEAR

    OpenAIRE

    LUCA Cornelia; Rãzvan MOCANU

    2013-01-01

    The leather confections industry uses the silicone rubber moulds for the symbols,notices and models stamping on the footwear or morocco goods parts. The paper presents somecontributions in this kind of devices manufacturing technology

  4. CHARACTERIZATION OF RUBBER DEGRADING ISOLATES

    OpenAIRE

    M. D. Chengalroyen; Dabbs, E R

    2012-01-01

    Sixteen soil samples were screened for the presence of rubber degrading strains. Twenty-five strains displaying clear zone formation on latex agar plates were purified. Identification revealed that twenty three of these isolates were Streptomyces species, one Pseudonocardia species and one Methylibium species. The addition of carbon sources with the exception of tween 80 enhanced extracellular rubber biodegradation. Scanning electron microscopy revealed that the isolates were able to colonize...

  5. Rubber friction on smooth surfaces

    OpenAIRE

    Persson, B.N.J.; Volokitin, A. I.

    2006-01-01

    We study the sliding friction for viscoelastic solids, e.g., rubber, on hard flat substrate surfaces. We consider first the fluctuating shear stress inside a viscoelastic solid which results from the thermal motion of the atoms or molecules in the solid. At the nanoscale the thermal fluctuations are very strong and give rise to stress fluctuations in the MPa-range, which is similar to the depinning stresses which typically occur at solid-rubber interfaces, indicating the crucial importance of...

  6. 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.

  7. Tribology Aspect of Rubber Shock Absorbers Development

    Directory of Open Access Journals (Sweden)

    M. Banić

    2013-09-01

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

  8. Posthuman blues

    CERN Document Server

    Tonnies, Mac

    2013-01-01

    Posthuman Blues, Vol. I is first volume of the edited version of the popular weblog maintained by author Mac Tonnies from 2003 until his tragic death in 2009. Tonnies' blog was a pastiche of his original fiction, reflections on his day-to-day life, trenchant observations of current events, and thoughts on an eclectic range of material he culled from the Internet. What resulted was a remarkably broad portrait of a thoughtful man and the complex times in which he lived, rendered with intellige...

  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. Electrospinning of PVC with natural rubber

    International Nuclear Information System (INIS)

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

  11. 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.

  12. Tear fluid signs associated with filtration blebs, as demonstrated by three-dimensional anterior segment optical coherence tomography

    OpenAIRE

    Kojima S; Inoue T.; Kawaji T; Tanihara H

    2014-01-01

    Sachi Kojima, Toshihiro Inoue, Takahiro Kawaji, Hidenobu TaniharaDepartment of Ophthalmology, Faculty of Life Sciences, Kumamoto University, Chuo-ku, Kumamoto, JapanPurpose: To determine the clinical features of tear fluid signs associated with filtration blebs via three-dimensional anterior segment optical coherence tomography (3D AS-OCT).Methods: In total, 152 eyes (130 patients) with glaucoma that underwent trabeculectomy with mitomycin C were evaluated retrospectively. We investigated tea...

  13. Bleb formation is induced by alkaline but not acidic pH in estrogen receptor silenced breast cancer cells.

    Science.gov (United States)

    Khajah, Maitham A; Mathew, Princy M; Alam-Eldin, Nada S; Luqmani, Yunus A

    2015-04-01

    De novo and acquired resistance to endocrine-based therapies in breast cancer occurs in parallel with epithelial to mesenchymal transition (EMT), which is associated with enhanced proliferative and metastatic potential, and poor clinical outcome. We have established several endocrine insensitive breast cancer lines by shRNA-induced depletion of estrogen receptor (ER) by transfection of MCF7 cells. All of these exhibit EMT. We have previously reported that brief exposure of specifically ER- breast cancer cells, to extracellular alkaline pH, results in cell rounding and segregation, and leads to enhanced invasive potential. In this study we describe more detailed morphological changes and compare these with cell exposure to acidic pH. Morphological changes and localization of various molecules critical for cell adhesion and motility, associated with pH effects, were assessed by live cell microscopy, electron microscopy, and immunofluorescence. Exposure of either ER- or ER+ breast cancer cells to extracellular acidic pH did not induce significant changes in morphological appearance. Conversely, brief exposure of specifically ER silenced cells, to alkaline pH, resulted in cell contractolation and formation of bleb-like actin-rich structures which were evenly distributed on the outer membrane. Integrin α2, FAK, and JAM-1 were found in the cytoplasm streaming into the newly formed blebs. These blebs appear to be related to cell polarity and movement. Pre-treatment with cytochalasin-D or inhibitors of Rho or MLCK prevented both contractolation and bleb formation. Our data suggest that the effect of pH on the microenvironment of endocrine resistant breast cancer cells needs to be more extensively investigated. Alkaline, rather than acidic pH, appears to induce dramatic morphological changes, and enhances their invasive capabilities, through re-organization of cortical actin. PMID:25672508

  14. Microbial Degradation of Natural Rubber Vulcanizates

    OpenAIRE

    Tsuchii, Akio; Suzuki, Tomoo; Takeda, Kiyoshi

    1985-01-01

    An actinomycete, Nocardia sp. strain 835A, grows well on unvulcanized natural rubber and synthetic isoprene rubber, but not on other types of synthetic rubber. Not only unvulcanized but also various kinds of vulcanized natural rubber products were more or less utilized by the organism as the sole source of carbon and energy. The thin film from a latex glove was rapidly degraded, and the weight loss reached 75% after a 2-week cultivation period. Oligomers with molecular weights from 104 to 103...

  15. Rubber friction and tire dynamics

    Science.gov (United States)

    Persson, B. N. J.

    2011-01-01

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

  16. Fire safety of rubber bearings

    International Nuclear Information System (INIS)

    The objective of the study is to experimentally evaluate the fire resistance of the natural-rubber bearings to be incorporated into a Fast Reactor (FBR) under study. Four experiments were performed to look at the effect of bearing diameters and heating conditions on the performance. The full-scale specimen sustained the design-basis load for more than 3.5 hours under 'standard fire.' Medium-size bearings showed resistance for 2-4 hours, according to heating temperatures. The paper also summarizes the methods and the results of simulation analyses of rubber bearings subjected to load/temperature conditions under fire. The vertical deformation of the bearings can be calculated very well, using the temperature profiles obtained from testing. However, the heat transfer analyses did not give good results, especially in the cases/portions where heat was generated due to rubber combustion. (author)

  17. Rubber friction and tire dynamics

    International Nuclear Information System (INIS)

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

  18. Screening of Natural Rubber-Degrading Microorganisms from Rubber Processing Factory Waste in Vietnam

    OpenAIRE

    Nguyen Lan Huong; To Kim Anh; Phan Trung Nghia; Dao Viet Linh; Bui Thi Trang; Masao Fukuda

    2013-01-01

    Natural rubber-degrading microorganisms were isolated from waste of rubber processing factory in Cam Thuy of Vietnam. Four of them belong to Streptomyces sp. that showed the higher abilities for natural rubber degradation than the others. They are able to use both deproteinised natural rubber (DPNR) and synthetic rubber cis-1,4-polyisoprene (SR) as a sole source of carbon. Gel permeation chromatography (GPC) analysis revealed that these strains degraded DPNR and SR to low-molecular-weight pro...

  19. 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.

  20. Improved rubber nanofillers

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, T. J.

    2012-03-01

    During this task, Silane functionalized TiO2 and HK3Ti4O4(SiO4)3 were sent to Goodyear (GY) for testing. These materials were characterized based on their interaction with the model elastomer, squalene. The Van der Waals interactions and Hamaker Constants for ZnO particles in squalene and rubber materials were characterized and it was determined that a 10-20 nm spacing was necessary between primary filler particles to maintain a stable nanocomposite. Contact angle measurements on the ZnO and ZnO-silane materials indicated that the solvent should wet the particles, and solvophobic attractions should not be present. These studies showed that the surface modification with sulfosilane coupling agents was successful, and high levels of dispersion of the particles remained possible. Further, a novel surface charging phenomenon where negative surface charging is developed in the squalene environment was observed and corroborated by measurements of particle size and of the surface modified materials in squalene. This impacts the dispersion of the particles according to the traditional colloidal interpretation of electrostatic repulsive forces between particles. Additionally, thin nanocomposite fibers were developed using electrospinning. The size and shape of the oxides did not change during the electrospinning process, although the shape of the fiber and the distribution of the particles, particularly for ZnO, was not ideal. There was an obvious increase in elastic modulus and hardness from the addition of the oxides, but differentiating the oxides, and particularly the surfactants, was difficult. The A-1289 lead to the greatest dispersion of the filler particles, while the A-1589 and the NXT produced clustered particle aggregates. This agrees with previous study of these materials in low molecular weight squalene solvent studies reported earlier. The behavior of the nanoparticle ZnO and the microparticle silica is different as well, with the ZnO being contained within

  1. Chemicals used in the rubber industry.

    Science.gov (United States)

    Fishbein, L

    1991-01-01

    Hundreds of chemicals and mixtures illustrative of many structural and use categories are employed in the rubber industry. Global utilization of natural rubber and synthetic elastomers as well as rubber-processing chemicals are projected to increase in the foreseeable future. Primary focus is centered on the major rubber processing chemicals and elastomer monomers in regard to their utility, production trends, structural characteristics, nature of potential impurities, and toxicology (primarily carcinogenicity and genotoxicity). Additionally, areas of specific exposure concern and epidemiology in the rubber industry are considered. PMID:2057768

  2. Analisa Kadar Nitrogen Dalam Crumb Rubber Mutu Sir 20 Dan Crumb Rubber Mutu Sir 3 Metode Kjeldhal

    OpenAIRE

    Singarimbun, William Prodis

    2011-01-01

    Was done compare analysis titrates nitrogen in rubber SIR 20 by rubber SIR 3 at PT. Bridgestone Sumatra Rubber Estate Dolok Melangir, where does analysis need is done to know rubber rate compare SIR 20 by rubber SIR 30. Compare analysis so effective is done in determine top-grade crumb rubber quality bases classification among SIR'S quality 20 by SIR'S qualities 3. Parameter that is utilized is know to titrate greater or smaller nitrogen bases Standart Indonesian Rubber (SIR) already been det...

  3. Imaging of filtering blebs after implantation of the Ex-PRESS shunt with the use of the Visante optical coherence tomography

    Institute of Scientific and Technical Information of China (English)

    Aristeidis; Konstantinidis; Georgios; D; Panos; Magdalini; Triantafylla; Georgios; Labiris; Efthimia; Tsaragli; Zisis; Gatzioufas; Vassilios; Kozobolis

    2015-01-01

    AIM: To analyze the features of the filtering blebs following implantation of the Ex-PRESS glaucoma device(model P-50) with the aid of the Visante anterior segment optical coherence tomography(AS-OCT)METHODS: Five patients with open angle glaucomas were included in the study. They all underwent implantation of the Ex-PRESS device under a scleral flap. The surgical procedure was augmented with the use of mitomycin C subconjunctivally. The filtering blebs were analyzed with the Visante AS-OCT with the scans taken along the axis of the implantation of the glaucoma device.RESULTS: All filtering blebs were graded as diffuse functioning. The morphological characteristics of the blebs were similar to those of the trabeculectomy.However the use of the Ex-PRESS implant tend to form a characteristic episcleral lake at the site of the plate of the implant. CONCLUSION: The use of the Ex-PRESS implant produces filtering blebs similar to those of the trabeculectomy with the formation of a characteristic episcleral lake at the site of the plate of the implant.

  4. Thermomechanical characterisation of cellular rubber

    Science.gov (United States)

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

    2016-01-01

    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.

  5. Railway Time and Rubber Time

    OpenAIRE

    Tsuji, Yohko

    2006-01-01

    Abstract This article addresses the co-existence of rigid punctuality and a rubber-like flexibility in the Japanese conception of time. It examines how the clock and social norms shape the everyday use of time related to railways, work, and appointments in Japan. It demonstrates that multiple discourses of time and the complicated interactions among them create temporal complexity in which the seeming ...

  6. Innovative synthetic rubbers via ruthenium catalyst systems

    OpenAIRE

    Tuba, Robert; Grubbs, Robert H.

    2013-01-01

    The trans-polypentenamer has unique relevance among the synthetic rubbers since it has similar phys. properties to the natural rubber. The polypentenamer additives have propitious effect on the tire properties and have been studied extensively for this application. Polypentenamer synthetic rubber was synthesized by ringopening metathesis polymn. (ROMP) using ruthenium catalyst systems. It was found that the cyclopentene conversion does not depend on the catalyst activity and catal...

  7. 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. PMID:22139094

  8. Radiation curing of natural rubber latex

    International Nuclear Information System (INIS)

    Natural rubber latex (60% solids) was irradiated with Cobalt-60 gamma radiation upto 30 megarads. It was observed that 90% of the rubber was cross-linked at a cumulative dose of 2 megarads to 12 megarads. In case of the coagulated latex 74% of the rubber was cross-linked at the same dose. Thereafter the percentage cross-linked polymer decreased continuously upto 16 megarads in both the cases but increased again. (auth.)

  9. PERILAKU MEKANIK BETON DENGAN CRUMB RUBBER

    OpenAIRE

    MUHAIMIN, AHMAD AKI

    2015-01-01

    Kebutuhan produksi ban di Indonesia terus meningkat, namun pemanfaatan limbah ban yang tidak terpakai sangat terbatas. Sehingga perlu memikirkan alternatif penggunaan limbah ban untuk pekerjaan konstruksi beton. Berkaitan dengan ini, diadakan penelitian yang menggunakan crumb rubber sebagai limbah ban dengan variasi subtitusi crumb rubber terhadap pasir dalam beton yaitu 0%, 10%, 20%, dan 30%. Selain itu untuk meningkatkan ikatan crumb rubber terhadap campuran beton maka digunakan larutan NaO...

  10. Autoantibodies from mice exposed to Libby amphibole asbestos bind SSA/Ro52-enriched apoptotic blebs of murine macrophages

    International Nuclear Information System (INIS)

    Asbestos exposure is associated with increased autoimmune responses in humans. For example, in Libby, MT where significant asbestos exposure has occurred due to an asbestos-contaminated vermiculite mine near the community, residents have developed increased autoimmune responses compared to an unexposed population. However, the exact mechanism by which Libby amphibole asbestos generates autoimmune responses is unclear. A murine model of amphibole asbestos-induced autoimmunity was recently established, and one of the targets of the autoantibodies (AAs) was the SSA/Ro52 autoantigen. The purpose of this study was to determine whether the SSA/Ro52 autoantigen is exposed at the surface of cells as a result of asbestos exposure as a possible mechanism leading to antigenicity. Our results indicate that Libby asbestos induces apoptosis in murine macrophages as determined by phosphatidylserine exposure, cleavage of poly(ADP-ribose) polymerase and morphological changes such as nuclear condensation. Moreover, asbestos-induced apoptosis results in the formation of apoptotic cell surface blebs enriched in SSA/Ro52 as determined by confocal microscopy. Most importantly, apoptotic cell surface blebs are recognized by AAs from mice exposed to amphibole asbestos suggesting that these cell surface structures may be antigenic when presented in a pro-inflammatory context. This study supports the hypothesis that the induction of apoptosis plays a key role in environmentally induced autoimmunity through cell surface exposure of a known autoantigen

  11. The effect of phacoemulsification on late bleb failure or intraocular pressure in patients with glaucoma: a systematic review

    Directory of Open Access Journals (Sweden)

    Peponis VG

    2012-07-01

    Full Text Available Vasileios G Peponis,* Spyridon E Chalkiadakis,* Michail C Katzakis, Efstratios A ParikakisOphthalmiatreio Athens Eye Hospital, Second Ophthalmology Department, Athens, Greece*These authors contributed equally in writing the manuscriptAbstract: The purpose of our systematic review is to document the adverse events that follow phacoemulsification in eyes with trabeculectomy due to glaucoma and to determine whether phacoemulsification jeopardizes the survival of the trabeculectomy. Our research was based on English- and non-English-language articles obtained using the Medline, Embase, Web of Science and Scopus databases. Additional studies were identified by searching bibliographies in the British Library and abstracts presented at the Association for Research in Vision and Ophthalmology annual meetings. Search terms included randomized controlled trial, controlled clinical trial, random allocation, double-blind method, matched studies and trabeculectomy failure, glaucoma-filtering operation failure, bleb failure and cataract surgery or phacoemulsification. Only prospective or retrospective matched studies testing the survival of a trabeculectomy alone versus clear corneal phacoemulsification after a trabeculectomy in patients with glaucoma were included. Data were independently extracted by two authors using predefined data fields. PubMed yielded 152 results, Scopus 235, Embase 222, and Web of Science (science citation index 216. We read the abstracts of all the trials, and after reading the full text of 31 studies, we decided that 13 studies should be comprehensively evaluated. Current evidence does not allow us to draw safe conclusions on the scientific question so far.Keywords: bleb failure, cataract, glaucoma, phacoemulsification, trabeculectomy

  12. Genetic disruption of calpain correlates with loss of membrane blebbing and differential expression of RhoGDI-1, cofilin and tropomyosin

    DEFF Research Database (Denmark)

    Larsen, Anna Karina; Lametsch, Rene; Elce, John S.;

    2008-01-01

    cleavage of focal adhesion components and signalling molecules. In this study, the live-cell morphology of calpain-knockout and wild type cells was examined by time-lapse fluorescence microscopy and a role of calpain in mediating formation of sporadic membrane blebs was established. Membrane blebbing was...... role of calpain in regulating membrane extensions involving these proteins. RhoGDI, cofilin and tropomyosin are known regulators of actin filament dymamics and membrane extensions. The reduced levels of RhoGDI-1 in calpain-knockout cells observed by proteome analysis were confirmed by immunoblotting...

  13. Behavior of asphalt-rubber hot mixes obtained with high crumb rubber contents

    OpenAIRE

    Dantas Neto, Silvrano A.; Farias, Márcio Muniz de; Pais, Jorge C.; Pereira, Paulo A. A.; Santos, Luís Picado

    2003-01-01

    This paper shows the results of a study about the mechanical behavior of dense graded asphalt-rubber hot mixes (grading envelope C of DNER-ES 313/97) 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 5...

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

    OpenAIRE

    Neto, Silvrano Adonias Dantas; Farias, Márcio Muniz de; 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...

  15. Blue cures blue but be cautious

    Directory of Open Access Journals (Sweden)

    Pranav Sikka

    2011-01-01

    Full Text Available Methemoglobinemia is a disorder characterized by the presence of >1% methemoglobin (metHb in the blood. Spontaneous formation of methemoglobin is normally counteracted by protective enzyme systems, for example, nicotinamide adenine dinucleotide phosphate (NADPH methemoglobin reductase. Methemoglobinemia is treated with supplemental oxygen and methylene blue (1-2 mg/kg administered slow intravenously, which acts by providing an artificial electron acceptor for NADPH methemoglobin reductase. But known or suspected glucose-6-phosphate dehydrogenase (G6PD deficiency is a relative contraindication to the use of methylene blue because G6PD is the key enzyme in the formation of NADPH through pentose phosphate pathway and G6PD-deficient individuals generate insufficient NADPH to efficiently reduce methylene blue to leukomethylene blue, which is necessary for the activation of the NADPH-dependent methemoglobin reductase system. So, we should be careful using methylene blue in methemoglobinemia patient before G6PD levels.

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

    Directory of Open Access Journals (Sweden)

    Velu CHANDRAN

    2016-05-01

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

  17. Prediction of heat generation in rubber or rubber-metal springs

    Directory of Open Access Journals (Sweden)

    Banić Milan S.

    2012-01-01

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

  18. Innovative Neutron Shielding Material Composing of Natural Rubber-Styrene Butadiene Rubber Blends Diboron Trioxide

    International Nuclear Information System (INIS)

    The optimized flexible and lightweight neutron shielding materials were designed using the Monte Carlo N-Particle (MCNP) code. The neutron shielding materials thickness for 10 mm and 100 mm were considered for the neutron shielding performance. Results indicated that 10 mm shielding material of rubber compound between natural rubber (NR) and styrene butadiene rubber (SBR) blend (1:1) compose with diboron trioxide 60 phr and 100 mm shielding material for 4 layers structure of rubber compound between natural rubber (NR) and styrene butadiene rubber (SBR) blend compose with diboron trioxide 10 phr and rubber compound with iron oxide 100 phr offered advantages on neutron shielding compared to other designs. Experimental for these shielding material results verified the correctness of the optimal design and fabrication. The designed shielding materials are highly suitable for applications in nuclear science and technology.

  19. 75 FR 38119 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-07-01

    ... from Japan (38 FR 33593). Following five-year reviews by the Department of Commerce (``Commerce'') and... imports of polychloroprene rubber from Japan (64 FR 47765, September 1, 1999). Following second five-year... antidumping duty finding on imports of polychloroprene rubber from Japan (70 FR 44893). The Commission is...

  20. 75 FR 57980 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-09-23

    ... interested parties did not participate in this sunset review * * *.'' (75 FR 51981). Accordingly, pursuant to... 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...

  1. Zinc leaching from tire crumb rubber.

    Science.gov (United States)

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

    2012-12-01

    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. PMID:23145882

  2. THE RUBBER SHOWCASE IN SUMATRA

    OpenAIRE

    Penot, Eric

    2004-01-01

    As with cocoa a combination of available land and centres with fairly dense population is a prerequisite for a boom. But in the case of rubber the boom has been far more progressive than that for cocoa due to 3 main factors. Firstly, Sumatra and Kalimantan islands were almost empty at the turn of the century with population density inferior to 5 inhabitants/km². It took time for migrants (mainly from neighbouring Java in the case of Sumatra) as well as indigenous population (local Dayak and ...

  3. Assessment of Filtration Bleb and Endplate Positioning Using Magnetic Resonance Imaging in Eyes Implanted with Long-Tube Glaucoma Drainage Devices.

    Directory of Open Access Journals (Sweden)

    Ichiya Sano

    Full Text Available To evaluate ocular fluid filtration and endplate positioning in glaucomatous eyes with long-tube glaucoma drainage devices (GDDs using magnetic resonance imaging (MRI and the effects of various factors on postoperative intraocular pressure (IOP.This observational case series included 27 consecutive glaucomatous eyes (18 men, 7 women; mean age ± standard error, 63.0±2.0 years who underwent GDD implantation (n = 8 Ahmed Glaucoma Valves [AGV] and n = 19 Baerveldt Glaucoma Implants [BGI]. Tubes were inserted into the pars plana in 23 eyes and anterior chamber in 4 eyes. Six months postoperatively, high-resolution orbital images were obtained using 3-Tesla MRI with head-array coils, and the filtering bleb volume, bleb height, and distances between the anterior endplate edge and corneal center or limbus or between the endplate and orbital wall were measured.In MR images obtained by three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA sequences, the shunt endplate was identified as low-intensity signal, and the filtering bleb was identified as high-intensity signals above and below the endplate in all eyes. The 6-month-postoperative IOP level was correlated negatively with bleb volume (r = -0.4510, P = 0.0182 and bleb height (r = -0.3954, P = 0.0412. The postoperative IOP was significantly (P = 0.0026 lower in BGI-implanted eyes (12.2±0.7 mmHg than AGV-implanted eyes (16.7±1.2 mmHg; bleb volume was significantly (P = 0.0093 larger in BGI-implanted eyes (478.8±84.2 mm3 than AGV-implanted eyes (161.1±52.3 mm3. Other parameters did not differ.The presence of intraorbital/periocular accumulation of ocular fluid affects postoperative IOP levels in eyes implanted with long-tube GDDs. Larger filtering blebs after BGI than AGI implantations explain lower postoperative IOP levels achieved with BGI than AGV. The findings will contribute to better understanding of IOP reducing mechanism of long-tube GDDs.

  4. Myotonic dystrophy protein kinase (DMPK) induces actin cytoskeletal reorganization and apoptotic-like blebbing in lens cells

    Science.gov (United States)

    Jin, S.; Shimizu, M.; Balasubramanyam, A.; Epstein, H. F.

    2000-01-01

    DMPK, the product of the DM locus, is a member of the same family of serine-threonine protein kinases as the Rho-associated enzymes. In DM, membrane inclusions accumulate in lens fiber cells producing cataracts. Overexpression of DMPK in cultured lens epithelial cells led to apoptotic-like blebbing of the plasma membrane and reorganization of the actin cytoskeleton. Enzymatically active DMPK was necessary for both effects; inactive mutant DMPK protein did not produce either effect. Active RhoA but not constitutive GDP-state mutant protein produced similar effects as DMPK. The similar actions of DMPK and RhoA suggest that they may function in the same regulatory network. The observed effects of DMPK may be relevant to the removal of membrane organelles during normal lens differentiation and the retention of intracellular membranes in DM lenses. Copyright 2000 Wiley-Liss, Inc.

  5. Restoration of pretrabeculectomy visual acuity and a functioning filtering bleb in an eye with delayed suprachoroidal haemorrhage following trabeculectomy.

    Science.gov (United States)

    Senthil, Sirisha; Gupta, Supriya; Balijepalli, Pasyanthi

    2015-01-01

    A 35-year-old myopic man with juvenile open angle glaucoma was referred to us with fluctuating intraocular pressure (IOP) and progression in his only seeing left eye. He had systemic features suggestive of Marfan's syndrome. He underwent trabeculectomy with low dose mitomycin-C with operative precautions to prevent postoperative hypotony in view of high myopia and scleral thinning. On the second postoperative day, he had severe pain in his left eye, with vomiting, and presented with decreased vision, high IOP and a flat anterior chamber. Ultrasound B scan revealed 360° haemorrhagic choroidal detachment. He was conservatively managed and monitored over the next 1 month with appropriate medical treatment. He not only recovered his pretrabeculectomy visual acuity but also had a well functioning bleb at the end of 2 months. PMID:26661281

  6. Preparation and characterization of activated carbon from rubber-seed shell by physical activation with steam

    International Nuclear Information System (INIS)

    The use of rubber-seed shell as a raw material for the production of activated carbon with physical activation was investigated. The produced activated carbons were characterized by Nitrogen adsorption isotherms, Scanning electron microscope, Thermo-gravimetric and Differential scanning calorimetric in order to understand the rubber-seed shell activated carbon. The results showed that rubber-seed shell is a good precursor for activated carbon. The optimal activation condition is: temperature 880 oC, steam flow 6 kg h-1, residence time 60 min. Characteristics of activated carbon with a high yield (30.5%) are: specific surface area (SBET) 948 m2 g-1, total volume 0.988 m3 kg-1, iodine number of adsorbent (qiodine) 1.326 g g-1, amount of methylene blue adsorption of adsorbent (qmb) 265 mg g-1, hardness 94.7%. It is demonstrated that rubber-seed shell is an attractive source of raw material for producing high capacity activated carbon by physical activation with steam.

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

    Science.gov (United States)

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

    2000-08-01

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

  8. 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.

  9. 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.

  10. 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.

  11. Butterfly valve of all rubber lining type

    International Nuclear Information System (INIS)

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

  12. A study on existing rubber elasticity theories for stress-strain behavior of rubber-like networks

    Czech Academy of Sciences Publication Activity Database

    Meissner, Bohumil

    2003-01-01

    Roč. 38, č. 2 (2003), s. 157-166. [International Rubber Conference. Prague, 01.07.2002-04.07.2002] R&D Projects: GA AV ČR KSK4050111 Keywords : rubber elasticity theory * natural rubber * isoprene rubber Subject RIV: CD - Macromolecular Chemistry

  13. Thermal properties of hydrogenated liquid natural rubber

    Science.gov (United States)

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

    2015-09-01

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

  14. 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

  15. Fatigue life of automotive rubber jounce bumper

    International Nuclear Information System (INIS)

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

  16. Thermal properties of hydrogenated liquid natural rubber

    International Nuclear Information System (INIS)

    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

  17. Fatigue life of automotive rubber jounce bumper

    Energy Technology Data Exchange (ETDEWEB)

    Sidhu, R S [Automotive Engineering Unit, Institute of Advanced Technology, University Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia); Ali, Aidy, E-mail: aidy@eng.upm.edu.my [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM, Serdang Selangor (Malaysia)

    2010-05-15

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

  18. Modification of rubber by ion bombardment

    International Nuclear Information System (INIS)

    The paper presents selected effects of surface modification of rubber vulcanizates upon irradiation with He+, O+ or Ar+ ions. Changes to chemical composition and physical structure of rubber macromolecules are discussed in terms of influence of the treatment on functional properties of the vulcanizates, like friction and wettability. Hydrogen release, responsible for further crosslinking and oxidation of surface layer can protect bulk of the materials from action of external chemical factors. Effectiveness of a protective layer being formed due to ion bombardment has been examined from the point of view of thermal and ozone aging, as well as fuel resistance of the rubber vulcanizates.

  19. 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....

  20. 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.

  1. Analysis of rubber supply in Sri Lanka

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, M.J.; Nerlove, M.; Peters, R.K. Jr.

    1987-11-01

    An analysis of the supply response for perennial crops is undertaken for rubber in Sir Lanka, focusing on the uprooting-replanting decision and disaggregating the typical reduced-form supply response equation into several structural relationships. This approach is compared and contrasted with Dowling's analysis of supply response for rubber in Thailand, which is based upon a sophisticated reduced-form supply function developed by Wickens and Greenfield for Brazilian coffee. Because the uprooting-replanting decision is central to understanding rubber supply response in Sri Lanka and for other perennial crops where replanting activities dominate new planting, the standard approaches do not adequately capture supply response.

  2. Effect of crumb rubber origin on asphalt rubber hot mix laboratory performance

    OpenAIRE

    Pais, Jorge C.; Sousa, Jorge B.; Saim, Rachid; Pereira, Paulo A. A.

    2001-01-01

    Asphalt rubber traditionally has been produced with crumb rubber coming from an ambient grinding process and mostly from car tires. With this product and the binders used in Arizona and California the specifications currently present in ASTM D 6114 have been established. Nowadays relatively new types of crumb rubber are available in the markets namely those that have been produced by cryogenic methods and can then be reprocessed if desired by a further ambient step such as through a crack...

  3. 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

  4. Failure tests of laminated rubber bearings

    International Nuclear Information System (INIS)

    Three different types of rubber bearing - natural rubber bearing (NRB), lead-rubber bearing (LRB), and high-damping rubber bearing (HRB) - were tested up to failure under various combinations of axial and shear forces. The test results are summarized as follows: 1) Offset shear strain greatly affects tensile behavior and failure. 2) Axial stress or strain does not so greatly affect shear behavior and failure. 3) The characteristics of NBR and LRB are almost independent of strain rate, but those of HRB depend greatly on it. 4) Cyclic loading affects large-deformation behavior and failure to some extent. 5) failure limits which include the interaction between axial stress and shear strain were quantitatively evaluated. 6) A lead plug of LRB has no bad influence on failure. These will be very useful for developing an ultimate response prediction technique, which is necessary to establish rational design philosophy of base isolation systems for FBR plants. (author)

  5. Radiation stability of plastics and rubbers

    International Nuclear Information System (INIS)

    Physical radiation effects of #betta# particles, #betta#-radiation, x rays and accelerated electrons on thermosets, thermoplastics and rubbers are charted. Modifications to the information due to composition, shape and environment are noted. (U.K.)

  6. Rubber smallholders' flexibility No windfall, no crisis

    OpenAIRE

    Penot, E.,; F. Ruf

    2001-01-01

    A few decades ago rubber was one of the first tree crops to be characterized by a spectacular breakthrough, the production of new, highly productive clonal material. With regard to rubber, the adoption of clonal planting materials led to a spectacular improvement in labour-productivity and revenues. It requires also different cropping patterns during immature period. An increase in return to labour costs is usually the first priority of smallholders. As this adoption of clones by smallholders...

  7. 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...

  8. Use of Recycled Tire Rubber in Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    More than 250 million scrap tires weighing more than 3 million tons are generated each year in the United States. This is considered as one of the major environmental challenges facing municipalities around the world because waste rubber is not easily biodegradable even after a long period of landfill treatment. One of the solutions suggested is the use of tire rubber particles as additives in cement-based materials. Experiments under the laboratory environments commonly presented that the us...

  9. Exploring the thermodynamics of a rubber band

    Science.gov (United States)

    Roundy, David; Rogers, Michael

    2013-01-01

    We describe an upper-division experiment in thermal physics where students measure the tension of a rubber band as a function of temperature and length and use a Maxwell relation to find the change in internal energy and entropy for an isothermal stretch. This allows students to experimentally check the predictions of the entropic spring model for elastomers and observe that the entropy does indeed decrease as a rubber band is stretched.

  10. Long-term mechanical properties of rubber

    OpenAIRE

    Bin Kamaruddin, Shamsul

    2013-01-01

    Natural rubber has a good potential to be used as a material for the development of wave energy converters (WECs). Generally, rubber has the ability to withstand very large strains without permanent deformation or fracture and is not much affected by exposure to water. This makes it ideal for applications related to wave energy converter (WECs). However, there is a need to predict the efficiency of performance over the full lifetime of such an application given that WECs will represent large,...

  11. Feeling blue? Blue phosphors for OLEDs

    Directory of Open Access Journals (Sweden)

    Hungshin Fu

    2011-10-01

    Full Text Available Research on organic light emitting diodes (OLEDs has been revitalized, partly due to the debut of the OLED TV by SONY in 2008. While there is still plenty of room for improvement in efficiency, cost-effectiveness and longevity, it is timely to report on the advances of light emitting materials, the core of OLEDs, and their future perspectives. The focus of this account is primarily to chronicle the blue phosphors developed in our laboratory. Special attention is paid to the design strategy, synthetic novelty, and their OLED performance. The report also underscores the importance of the interplay between chemistry and photophysics en route to true-blue phosphors.

  12. Adding crumb rubber into exterior wall materials.

    Science.gov (United States)

    Zhu, Han; Thong-On, Norasit; Zhang, Xiong

    2002-10-01

    In Arizona US, most houses are built with walls covered by stuccos/coatings/mortars. This paper presents an explorative investigation of adding crumb rubber into stuccos/coatings/mortars. A series of experiments are conducted to examine the thermal and mechanical performance of the crumb rubber mixes. The results show that, the mixes with crumb rubber do exhibit more desirable performances like being high in crack-resistance and thermal insulation, and low in thermal expansion/contraction. The drawback for the crumb rubber mixes is the reduction in compressive strength, but which can be compensated by other means. As a site experiment, an area of 100 square-feet of crumb rubber coatings for two mix designs is sprayed on a tire-adobe wall. After being sprayed more than 14 months, the coatings apparently are in good condition. Significance of this study is that this practice, if accepted, will yield improved products that consume large quantities of crumb rubber. PMID:12498477

  13. Blue-green algae

    Science.gov (United States)

    ... Lac Klamath, Anabaena, Aphanizomenon flos-aquae, Arthrospira maxima, Arthrospira platensis, BGA, Blue Green Algae, Blue-Green Micro-Algae, Cyanobacteria, Cyanobactérie, Cyanophycée, Dihe, Espirulina, Hawaiian Spirulina, Klamath, Klamath Lake Algae, Lyngbya wollei, Microcystis aeruginosa, ...

  14. Blue-green algae

    Science.gov (United States)

    ... unresponsive to other treatments, taking 500 mg of spirulina blue-green algae by mouth 3 times daily for 6 months ... was seen in undernourished children who were given spirulina blue-green algae with a combination of millet, soy and peanut ...

  15. Templated blue phases.

    Science.gov (United States)

    Ravnik, Miha; Fukuda, Jun-ichi

    2015-11-21

    Cholesteric blue phases of a chiral liquid crystal are interesting examples of self-organised three-dimensional nanostructures formed by soft matter. Recently it was demonstrated that a polymer matrix introduced by photopolymerization inside a bulk blue phase not only stabilises the host blue phase significantly, but also serves as a template for blue phase ordering. We show with numerical modelling that the transfer of the orientational order of the blue phase to the surfaces of the polymer matrix, together with the resulting surface anchoring, can account for the templating behaviour of the polymer matrix inducing the blue phase ordering of an achiral nematic liquid crystal. Furthermore, tailoring the anchoring conditions of the polymer matrix surfaces can bring about orientational ordering different from those of bulk blue phases, including an intertwined complex of the polymer matrix and topological line defects of orientational order. Optical Kerr response of templated blue phases is explored, finding large Kerr constants in the range of K = 2-10 × 10(-9) m V(-2) and notable dependence on the surface anchoring strength. More generally, the presented numerical approach is aimed to clarify the role and actions of templating polymer matrices in complex chiral nematic fluids, and further to help design novel template-based materials from chiral liquid crystals. PMID:26412643

  16. Application of 5-Fluorouracil-Polycaprolactone Sustained-Release Film in Ahmed Glaucoma Valve Implantation Inhibits Postoperative Bleb Scarring in Rabbit Eyes

    OpenAIRE

    Xiu-Zeng Bi; Wei-Hua Pan; Xin-Ping Yu; Zong-Ming Song; Zeng-Jin Ren; Min Sun; Cong-Hui Li; Kai-Hui Nan

    2015-01-01

    This study was designed to investigate whether 5-fluorouracil (5-Fu)-polycaprolactone sustained-release film in Ahmed glaucoma valve implantation inhibits postoperative bleb scarring in rabbit eyes. Eighteen New Zealand white rabbits were randomly divided into three groups (A, B and C; n = 6 per group). Group A received combined 5-Fu-polycaprolactone sustained-release film application and Ahmed glaucoma valve implantation, group B received local infiltration of 5-Fu and Ahmed glaucoma valve i...

  17. Radiation resistant modification of rubber blends with silicone-ethylene-propylene rubber of silicone-fluorine-contained rubber

    International Nuclear Information System (INIS)

    To improve the radiation resistance of dimethyl silicone rubber (DMS), the effects of blending with ethylene-propylene-diene terpolymer (EPDM) or tetrafluoroethylene-propylene copolymer (Copoly(TFE-P)) were studied. DMS was mixed mechanically with one of the above rubbers and a radical initiator. The mixture was molded at 1600C under a pressure of 100kg/cm2 for 30 min. Radiation resistances of these rubber blends were evaluated by measuring tensile and viscoelastic (torsion pendulum method) properties of sample sheets irradiated by cobalt 60 up to 200 Mrad (Dose rate, 0.5 Mrad/h) in air at room temperature. In DMS-EPDM blends, the radiation resistance increased monotonously with increasing volume content of EPDM because of the contribution of the higher radiation resistivity of EPDM. On the other hand, DMS-Copoly(TFE-P) blend had its maximum radiation resistance at 1:1 volume ratio. When irradiated separately, DMS was hardened by cross-linking, and Copoly(TFE-P) was softened by oxidative degradation. The appearance of maximum radiation resistance in the blend DMS-Copoly (TFE-P) rubber was attributed to the balancing of properties due to the radiation effects due to crosslinking or chain scission occuring in the component rubbers. (author)

  18. Substance P induces rapid and transient membrane blebbing in U373MG cells in a p21-activated kinase-dependent manner.

    Directory of Open Access Journals (Sweden)

    John Meshki

    Full Text Available U373MG astrocytoma cells endogenously express the full-length neurokinin 1 receptor (NK1R. Substance P (SP, the natural ligand for NK1R, triggers rapid and transient membrane blebbing and we report that these morphological changes have different dynamics and intracellular signaling as compared to the changes that we have previously described in HEK293-NK1R cells. In both cell lines, the SP-induced morphological changes are Gq-independent, and they require the Rho, Rho-associated coiled-coil kinase (ROCK signaling pathway. Using confocal microscopy we have demonstrated that tubulin is phosphorylated subsequent to cell stimulation with SP and that tubulin accumulates inside the blebs. Colchicine, a tubulin polymerization inhibitor, blocked SP-induced blebbing in U373MG but not in HEK293-NK1R cells. Although p21-activated kinase (PAK is expressed in both cell lines, SP induced rapid phosphorylation of PAK in U373MG, but failed to phosphorylate PAK in HEK293-NK1R cells. The cell-permeable Rho inhibitor C3 transferase inhibited SP-induced PAK phosphorylation, but the ROCK inhibitor Y27632 had no effect on PAK phosphorylation, suggesting that Rho activates PAK in a ROCK-independent manner. Our study demonstrates that SP triggers rapid changes in cell morphology mediated by distinct intracellular signaling mechanisms in U373MG versus HEK293-NK1R cells.

  19. Blue ocean strategy.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades. PMID:15559577

  20. Radiation degradation of spent butyl rubbers

    Science.gov (United States)

    Telnov, A. V.; Zavyalov, N. V.; Khokhlov, Yu. A.; Sitnikov, N. P.; Smetanin, M. L.; Tarantasov, V. P.; Shadrin, D. N.; Shorikov, I. V.; Liakumovich, A. L.; Miryasova, F. K.

    2002-03-01

    Radiation methods of materials modification applied in technological chains can have significant economical and ecological advantages as compared to the established chemical, thermal and mechanical methods. Each year the problems of nature resources economy through the use of production and consumption wastes acquire a more significant value, as it allows to solve also ecological issues along with economical ones. This is mostly acute in relation to polymeric systems based on saturated rubbers, for example butyl rubber (BR) used in the tyre industry, as due to their high resistance to the action of oxygen, ozone, solar radiation and bacteria, they contaminate the environment for rather a long period. At VNIIEF and KSPU experiments were carried out on application of electron beams with energy from 6 to 10 MeV for radiation destruction of spent rubber based on BR. The radiation-degraded material was tested for re-use in the formulation of initial diaphragm mixture, rubber mixture for producing rubberized fabric and roofing.

  1. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

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

  2. Improvements of natural rubber for flame resistance

    Directory of Open Access Journals (Sweden)

    Orasa Patarapaiboolchai

    2010-07-01

    Full Text Available The present invention provides a process for treating natural rubber to increase its flame retardant capability. Theprocess comprises a mixture of a natural rubber with, (a halogenated free flame retardant agent (zinc hydroxystannate;STORFLAM ZHS and (b halogenated flame retardant agent (decabromodiphenyl; Great Lake DE-83R and chlorinatedparaffins; Plastoil 152 and another material like antimony trioxide and aluminium hydroxide in appropriate amount, with ratio of halogenated flame retardant agent: antimony trioxide 3:1. In the resulting product with halogen flame retardant showed a more efficient flame retardant property than halogen free flame retardant, i.e. brominated flame retardant provide higher efficiency than chlorinated and ZHS, respectively. The minimum requirement ratio for being flame retardant of antimonytrioxide: brominated or chlorinated agent is 7:21 or 10:30 phr while aluminium hydroxide: ZHS is 10: 150 phr. It was found thatburning rate was zero for brominated and chlorinated agent used but not for zinc hydroxyl stannate system. Average time of burning (ATB was 135, 118 and 41 second for brominated, chlorinated and ZHS flame retardant, respectively. Average extent of burning (AEB was 24, 19 and 14 millimeters, respectively. An advantage of this invention is that chemicals (antimony trioxide and either brominated or chlorinated agent added to natural rubber have the effect of rendering the natural rubber flame-resistant like synthetic rubbers, chloroprene.

  3. 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. PMID:24734968

  4. Radiation degradation of spent butyl rubbers

    International Nuclear Information System (INIS)

    Radiation methods of materials modification applied in technological chains can have significant economical and ecological advantages as compared to the established chemical, thermal and mechanical methods. Each year the problems of nature resources economy through the use of production and consumption wastes acquire a more significant value, as it allows to solve also ecological issues along with economical ones. This is mostly acute in relation to polymeric systems based on saturated rubbers, for example butyl rubber (BR) used in the tyre industry, as due to their high resistance to the action of oxygen, ozone, solar radiation and bacteria, they contaminate the environment for rather a long period. At VNIIEF and KSPU experiments were carried out on application of electron beams with energy from 6 to 10 MeV for radiation destruction of spent rubber based on BR. The radiation-degraded material was tested for re-use in the formulation of initial diaphragm mixture, rubber mixture for producing rubberized fabric and roofing

  5. 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.

  6. Use of scrap rubber in asphalt pavement surfaces

    Science.gov (United States)

    Eaton, Robert A.; Roberts, Richard J.; Blackburn, Robert R.

    1991-12-01

    Scrap tire rubber was mixed into an asphalt concrete wearing course to study the effect of ice disbonding from the pavement surface under traffic. Rubber contents of 0, 3, 6, and 12 percent by weight were studied. Initial laboratory ice disbonding test results led to the development of a new paving material, Chunk Rubber Asphalt Concrete (CRAC), that uses larger pieces of rubber in a much denser asphalt concrete mix. Strength values doubled and ice disbonding performance was enhanced.

  7. Effects of preparation process on performance of rubber modified asphalt

    Science.gov (United States)

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

    2015-06-01

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

  8. INVESTIGATION OF ASPHALT PAVEMENT WITH ADDED CRUMB RUBBER

    OpenAIRE

    Mandula, Jan; Olexa, Tomaš; Holubka, Mariya; Salaiova, Brigita

    2014-01-01

    Waste tires must be recycled in environmentally safe ways that meet civil engineering concerns while fulfilling standards for construction materials. Used tires can be processed into rubber powders with particle sizes of 0–2 mm, a suitable fine aggregate for mixing into road pavements. We tested asphalt mixtures with rubber added using the dry method, comparing their properties with a traditional mixture. We tested asphalt–rubber mixtures with rubber incorporated at either ambient temperature...

  9. New York Blue

    Data.gov (United States)

    Federal Laboratory Consortium — New York Blue is used cooperatively by the Laboratory and Stony Brook University as part of the New York Center for Computation Sciences. Ranked as the 28th fastest...

  10. Code blue: seizures.

    Science.gov (United States)

    Hoerth, Matthew T; Drazkowski, Joseph F; Noe, Katherine H; Sirven, Joseph I

    2011-06-01

    Eyewitnesses frequently perceive seizures as life threatening. If an event occurs on the hospital premises, a "code blue" can be called which consumes considerable resources. The purpose of this study was to determine the frequency and characteristics of code blue calls for seizures and seizure mimickers. A retrospective review of a code blue log from 2001 through 2008 identified 50 seizure-like events, representing 5.3% of all codes. Twenty-eight (54%) occurred in inpatients; the other 22 (44%) events involved visitors or employees on the hospital premises. Eighty-six percent of the events were epileptic seizures. Seizure mimickers, particularly psychogenic nonepileptic seizures, were more common in the nonhospitalized group. Only five (17.9%) inpatients had a known diagnosis of epilepsy, compared with 17 (77.3%) of the nonhospitalized patients. This retrospective survey provides insights into how code blues are called on hospitalized versus nonhospitalized patients for seizure-like events. PMID:21546315

  11. 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.

  12. Anaerobic desulfurization of ground rubber with the thermophilic archaeon Pyrococcus furiosus--a new method for rubber recycling.

    Science.gov (United States)

    Bredberg, K; Persson, J; Christiansson, M; Stenberg, B; Holst, O

    2001-01-01

    The anaerobic sulfur-reducing archaeon Pyrococcus furiosus was investigated regarding its capacity to desulfurize rubber material. The microorganism's sensitivity towards common rubber elastomers and additives was tested and several were shown to be toxic to P. furiosus. The microorganism was shown to utilize sulfur in vulcanized natural rubber and an increase in cell density was obtained when cultivated in the presence of spent tire rubber. Ethanol-leached cryo-ground tire rubber treated with P. furiosus for 10 days was vulcanized together with virgin rubber material (15% w/w) and the mechanical properties of the resulting material were determined. The increase in the stress at break value and the decrease in swell ratio and stress relaxation rate obtained for material containing microbially treated rubber (compared to untreated material) show the positive effects of microbial desulfurization on rubber. PMID:11234957

  13. [Contemporary state of work conditions and occupational morbidity of workers engaged into rubber, mechanical rubber and tire industries].

    Science.gov (United States)

    Stepanov, E G; Galiullina, É F; Samsonov, V M; Kudriavtsev, V P; Davletgareeva, G R; Shakirova, É D; Khasanov, B G; Buliakov, R T; Kamilov, R F; Shakirov, D F

    2014-01-01

    Based on analysis of materials provided by occupational safety department PC "UZEMiK" and JSC "Kauchuk", the authors evaluate contemporary work conditions and occupational morbidity in workers engaged into rubber, mechanical rubber and tyre industries. PMID:25335420

  14. Anomalous crack propagation in reinforced natural rubber

    Science.gov (United States)

    Sotta, Paul; Gabrielle, Brice; Long, Didier; Vanel, Loic; Albouy, Pierre-Antoine; Peditto, Francesca

    2009-03-01

    In reinforced natural rubber, crack propagation in mode I exhibits rotation of the tear in a direction perpendicular to the usual one. Our objective is, first, to understand the impact of this phenomenon on fracture toughness of the material, and, secondly, to understand how this phenomenon is related to the specific properties of reinforced natural rubber. To this aim, we combine measurements of ultimate properties, measurements of the number and length of tear rotations as a function of loading velocity and temperature, and investigation of material heterogeneities at sub-micrometric scales, originating both from fillers and strain-induced crystallites (strain-induced crystallinity is measured up to failure by X ray diffraction), in natural rubber samples reinforced by nanometric aggregates. Observations suggest that tear rotation is related both to the mechanical anisotropy induced by strain-induced crystallinity and to the dissipative properties of the material at high strain.

  15. Crack propagation in rubber-like materials

    International Nuclear Information System (INIS)

    Crack propagation in rubber-like materials is of great practical importance but still not well understood. We study the contribution to the crack propagation energy (per unit area) G from the viscoelastic deformations of the rubber in front of the propagating crack tip. We show that G takes the standard form G(v,T) = G0[1+f(v,T)] where G0 is associated with the (complex) bond-breaking processes at the crack tip while f(v,T) is determined by the viscoelastic energy dissipation in front of the crack tip. As applications, we discuss the role of crack propagation for adhesion, rolling resistance and sliding friction for smooth surfaces, and for rubber wear. (topical review)

  16. Development of rubber gloves by radiation vulcanization

    International Nuclear Information System (INIS)

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

  17. 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.

  18. 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.

  19. 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.

  20. A sustainability review of domestic rubber from the guayule plant

    Science.gov (United States)

    Guayule (Parthenium argentatum Gray) is an arid-adapted, low-input perennial shrub native to Mexico and southern Texas that has received considerable attention as an alternative source of natural rubber. It has potential to replace the most common types of rubbers, including synthetic rubber derived...

  1. 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

  2. Naturally occurring amino acid: Novel curatives for chloroprene rubber

    NARCIS (Netherlands)

    Das, A.; Naskar, N.; Datta, R.N.; Bose, P.P.; Debnath, S.C.

    2006-01-01

    Polychloroprene is a diene rubber, but unlike other diene rubbers, its compounding with various additives and curing mechanisms is different. A derivative of thiourea, ethylene thiourea (ETU), is widely used to vulcanize chloroprene rubber (CR), and the vulcanizates thus obtained exhibit excellent m

  3. 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....

  4. 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)...

  5. Rapid determination of dry rubber content in natural rubber latex by low-resolution pulsed NMR technique

    International Nuclear Information System (INIS)

    The dry rubber content (DRC) of rubber latex varies considerably depending upon genetic and environmental conditions. To facilitate speedy evaluation of yield of experimental trees and quick payment to latex tappers on the basis of rubber content, there is need of a rapid and accurate method of determination of DRC in rubber latex. In the present paper a rapid, reliable and easy method for DRC determination using proton low resolution NMR is reported. 6 refs., 1 tab

  6. Characteristics of natural rubber latex from Indonesia

    International Nuclear Information System (INIS)

    Five field latexes from different clones have been characterized. The total solid content increases and the protein content decreases with increasing the age of rubber trees. The average particle size is between 190 and 234 nm. The number average molecular weight varies from 160,000 to 700,000 while the weight average molecular weight varies from 1,000,000 to 500,000. Negligivle difference was observed in the physical properties of rubber films prepared from the irradiated field latexes. (author)

  7. Economic Efficiency in Indian Rubber Industry

    OpenAIRE

    Sarba Priya Ray

    2011-01-01

    The article tries to assess the utilization efficiency of capacity of Indian rubber industry in terms of econometric framework for the period,1979-80 to 2008-09.Capacity output has been  obtained at the minimum point of short run average cost curve. The result suggests that there has been declining growth rate of capacity utilization in rubber industry of India during the post reforms period accompanied by declining output growth as well as capacity growth. There exists some excess capacity i...

  8. Asphalt rubber mixtures in Portugal: fatigue resistance

    OpenAIRE

    Miranda, Henrique; Batista, Fátima; Neves, José; Antunes, Maria de Lurdes; Fonseca, Paulo

    2009-01-01

    This paper presents a study concerning the fatigue behaviour of asphalt mixtures with bitumen modified with high content of crumb rubber used in Portugal. For assessing the fatigue behaviour of this type of mixtures, four asphalt mixtures with high content of crumb rubber were used: two field bituminous mixtures – an open-graded and a gap-graded – both with granite aggregates; and two laboratory manufactured bituminous mixtures – an open-graded mixture with granite aggregates and a gap-graded...

  9. The Dynamic Characteristics of Silicone Rubber Isolator

    Institute of Scientific and Technical Information of China (English)

    YU Lianjiang; LIU Suling; YE Linming; HUANG Guangsu; XU Yuntao

    2012-01-01

    The dynamic stiffness and the specific damping energy,as well as the vibration response characteristics of a silicone rubber isolator were researched.The results of the vibration test showed that the silicone rubber isolator was excellent in the performance of vibration control.The dynamic stiffness and the damping characteristics were non-linear.From the comparison between experimental results and simulation analysis,the displacement transmissibility characteristics of the isolator were obtained.As a result,the dynamic characteristics of the isolator could be accurately described by the quadratic type non-linear terms at small amplitude.

  10. Removal Water Turbidity by Crumb Rubber Media

    OpenAIRE

    Abeer I. Alwared; Muna Yousif Abdul-Ahad; Abbas H. Sulaymon

    2014-01-01

    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/...

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

    International Nuclear Information System (INIS)

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

  12. The role of the small rubber particle protein in determining rubber yields and polymer length in Russian dandelion

    Science.gov (United States)

    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 s...

  13. Simulation work of fatigue life prediction of rubber automotive components

    International Nuclear Information System (INIS)

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

  14. Simulation work of fatigue life prediction of rubber automotive components

    Energy Technology Data Exchange (ETDEWEB)

    Samad, M S A [Automotive Engineering Unit, Institute of Advanced Technology, University Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia); Ali, Aidy, E-mail: aidy@eng.upm.edu.my [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM, Serdang Selangor (Malaysia)

    2010-05-15

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

  15. Performance Study of the Natural Rubber Composite with Clay Minerals

    International Nuclear Information System (INIS)

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

  16. The Blues of David Lynch

    OpenAIRE

    Roche, David

    2009-01-01

    This article is an attempt to elaborate a typology of the color blue in the color films of David Lynch up to and including Mulholland Drive (2001). The color blue is considered alternately as light, matter or verbal language. The author studies the use, function, value and meaning of blue lighting, divided into static and flashing light, and of the blue objects in Blue Velvet (1986) and Mulholland Drive. The author shows how Lynch appropriates connotations Western culture, under the influence...

  17. 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...

  18. Properties of asphalt-rubber binders related to characteristics of the incorporated crumb rubber

    OpenAIRE

    Dantas Neto, Silvrano A.; Farias, Márcio Muniz de; Pais, Jorge C.; Pereira, Paulo A. A.; Santos, Luís Picado

    2003-01-01

    The behavior of asphalt binders modified with recycled crumb rubber depends on several factors, such as: rubber contents and type, temperature and time employed during the digestion process. This paper shows the results of a series of tests performed on asphaltrubber produced via the wet process. The tests included standard penetration, softening point, Brookfield viscosity and resilience. The results show that the limiting variable in the digestion process is the Brookfield vi...

  19. The potential for sunflower as a rubber-producing crop for the United States

    OpenAIRE

    Cornish K.; Pearson C.H.; Rath D.J.; Dong N.; Mcmahan C.M.; Whalen M.

    2007-01-01

    There are strategic as well as economic incentives to develop a renewable, United States-based supply of natural rubber. Currently, nearly all commercial natural rubber comes from a single species, the Brazilian rubber tree (Hevea brasiliensis) and the US is almost completely dependent on imports from distant countries. Global natural rubber production will be best served in the future by multiple natural rubber crops. However, for most rubber crops, the ability to produce rubber that is econ...

  20. 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.

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

    International Nuclear Information System (INIS)

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

  2. The rubber tree genome shows expansion of gene family associated with rubber biosynthesis

    Science.gov (United States)

    Lau, Nyok-Sean; Makita, Yuko; Kawashima, Mika; Taylor, Todd D.; Kondo, Shinji; Othman, Ahmad Sofiman; Shu-Chien, Alexander Chong; Matsui, Minami

    2016-01-01

    Hevea brasiliensis Muell. Arg, a member of the family Euphorbiaceae, is the sole natural resource exploited for commercial production of high-quality natural rubber. The properties of natural rubber latex are almost irreplaceable by synthetic counterparts for many industrial applications. A paucity of knowledge on the molecular mechanisms of rubber biosynthesis in high yield traits still persists. Here we report the comprehensive genome-wide analysis of the widely planted H. brasiliensis clone, RRIM 600. The genome was assembled based on ~155-fold combined coverage with Illumina and PacBio sequence data and has a total length of 1.55 Gb with 72.5% comprising repetitive DNA sequences. A total of 84,440 high-confidence protein-coding genes were predicted. Comparative genomic analysis revealed strong synteny between H. brasiliensis and other Euphorbiaceae genomes. Our data suggest that H. brasiliensis’s capacity to produce high levels of latex can be attributed to the expansion of rubber biosynthesis-related genes in its genome and the high expression of these genes in latex. Using cap analysis gene expression data, we illustrate the tissue-specific transcription profiles of rubber biosynthesis-related genes, revealing alternative means of transcriptional regulation. Our study adds to the understanding of H. brasiliensis biology and provides valuable genomic resources for future agronomic-related improvement of the rubber tree. PMID:27339202

  3. 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

  4. Economic Efficiency in Indian Rubber Industry

    Directory of Open Access Journals (Sweden)

    Sarba Priya Ray

    2011-12-01

    Full Text Available The article tries to assess the utilization efficiency of capacity of Indian rubber industry in terms of econometric framework for the period,1979-80 to 2008-09.Capacity output has been  obtained at the minimum point of short run average cost curve. The result suggests that there has been declining growth rate of capacity utilization in rubber industry of India during the post reforms period accompanied by declining output growth as well as capacity growth. There exists some excess capacity in the rubber industry which remains unutilized during our study period. The result exhibits that  high correlation coefficient between actual output and capacity output for Indian rubber sector implies that  major part of under utilization of capacity is intended and low correlation  between capacity expansion (CE and past utilization(CUL seems to suggest that under utilization, if any, is mainly of the unintended nature, capacity expansions do not  move in line with past utilization rates and it also indicates that abolition of restrictions on licensing due to trade liberalization do not  help industry to expand capacity. On the other hand, low correlation between capacity expansion (CE and lagged output (QL indicates that unintended excess capacity is varying from year to year in an unsystematic matter.

  5. FTIR investigation into Degradation of Natural Rubber

    Science.gov (United States)

    Rich, Ryan; Waldek Zerda, T.

    2006-10-01

    The aging of tires is of the highest concerns to the automotive industry, due to its implications in fuel economy and automobile safety. Previously, the high absorption rate of carbon black filled polymers has hindered the use of Fourier Transform Infrared Spectroscopy (FTIR) in studying this occurrence. However, recent developments in attenuated total reflection (ATR) techniques have provided a means for spectroscopically monitoring the composition changes induced in rubber blends by heat, exposure to ultra-violet radiation, and mechanical strain. The ATR apparatus, employing a germanium crystal, collected high quality infrared spectra at a reduced penetration depth of less than one micron. This research analyzed natural polymer blends with varied aggregate size and concentration of carbon black. The samples were analyzed as a function of exposure time to 70 C heat and UV radiation, as well elongation by mechanical strain. In these spectra, growth of the 1740cm-1 peak is assigned to increase populations of the C=O band. Carbon black filler rubber is shown to slow the rate of oxidation in pure natural rubber. Crystallization of rubber composites under strain is characterized by changes in the shapes of the CH stretch bands.

  6. 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.

  7. 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.

  8. 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. .

  9. Radiation modification of silicone rubber with glycidylmethacrylate

    International Nuclear Information System (INIS)

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

  10. Applications of irradiation to the rubber industry

    International Nuclear Information System (INIS)

    Free radicals are created in polymers by irradiation: macroscopic properties of these polymers are then modified by chemical reactions initiated by these radicals. Technological and economical characteristic of irradiation means are recalled, processes used for rubber are described. Specific advantages of irradiation are pointed out and future trends of the technique are forecasted

  11. 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...

  12. Rubber - application of radiation to tire manufacture

    International Nuclear Information System (INIS)

    Since the advent of commercial accelerators during the last several years capable of producing controllable electron beams of high energy, Firestone has devoted a considerable effort to the better understanding of the possible applications of such radiation to the production of tires or tire components. A number of chemical reactions can occur when elastomeric compounds are exposed to high energy waves, but crosslinking and degradation are the most important. The degree to which the crosslinking reaction predominates depends upon the nature of the rubber, compounding ingredients and the dosage. In general then, the effects achieved by the radiation of a rubber are quite similar to those resulting from heat. However, radiation cure or precure of compounds offers the advantage that the degree of crosslinking can be better controlled. Uniform crosslinking is possible since the high speed electrons penetrate uniformly throughout the sample. Curing with heat on the other hand may result in a greater degree of crosslinking on the surface of the sample than the center because of low heat conductivity. In general, radiation can be used to advantage to crosslink partially rubber tire components so that they retain better their shape and dimension during tire assembly and final cure or vulcanization. Added advantages of radiation precure include: a reduction of material usage, substitution of synthetic for natural rubber without loss in strength and the fact that partially crosslinked components will not thin out or become displaced during construction and vulcanization of the tire. (author)

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

    International Nuclear Information System (INIS)

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

  14. Beyond Deep Blue

    CERN Document Server

    Newborn, Monty

    2011-01-01

    More than a decade has passed since IBM's Deep Blue computer stunned the world by defeating Garry Kasparov, the world chess champion at that time. Beyond Deep Blue tells the continuing story of the chess engine and its steady improvement. The book provides analysis of the games alongside a detailed examination of the remarkable technological progress made by the engines - asking which one is best, how good is it, and how much better can it get. Features: presents a total of 118 games, played by 17 different chess engines, collected together for the first time in a single reference; details the

  15. The Blue Collar Brain

    Directory of Open Access Journals (Sweden)

    Guy eVan Orden

    2012-06-01

    Full Text Available Much effort has gone into elucidating control of the body by the brain, less so the role of the body in controlling the brain. This essay develops the idea that the brain does a great deal of work in the service of behavior that is controlled by the body, a blue collar role compared to the white collar control exercised by the body. The argument that supports a blue collar role for the brain is also consistent with recent discoveries clarifying the white collar role of synergies across the body's tensegrity structure, and the evidence of critical phenomena in brain and behavior.

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

    International Nuclear Information System (INIS)

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

  17. The "Blue Banana" Revisited

    NARCIS (Netherlands)

    Faludi, A.K.F.

    2015-01-01

    This essay is about the “Blue Banana”. Banana is the name given subsequently by others to a Dorsale européenne (European backbone) identified empirically by Roger Brunet. In a background study to the Communication of the European Commission ‘Europe 2000’, Klaus Kunzmann and Michael Wegener put forwa

  18. Blue spectral inflation

    CERN Document Server

    Schunck, Franz E

    2008-01-01

    We reconsider the nonlinear second order Abel equation of Stewart and Lyth, which follows from a nonlinear second order slow-roll approximation. We find a new eigenvalue spectrum in the blue regime. Some of the discrete values of the spectral index n_s have consistent fits to the cumulative COBE data as well as to recent ground-base CMB experiments.

  19. MAGNESIUM ION REGULATION OF THE IN VITRO RUBBER BIOSYNTHESIS BY PARTHENIUM ARGENTATUM GRAY

    Science.gov (United States)

    Natural rubber is produced by a rubber transferase (a cis-preny transferase). Rubber transferase uses allylic pyrophosphate to initiate the rubber molecule and isopentenyl pyrophosphate (IPP) to form the polymer. Rubber biosynthesis also requires a divalent metal cation. Understanding how molecular ...

  20. Properties of Waste Tire Rubber Powder

    Directory of Open Access Journals (Sweden)

    M. Bekhiti

    2014-08-01

    Full Text Available Scrap tires are abundant and alarming waste. The aggregates resulting from the crushing of the waste tires are more and more used in the field of civil engineering (geotechnical, hydraulic works, light concretes, asphaltic concretes, etc.. Depending on the type of the used tires, dimensions and possible separations and treatment, the physical and mechanical characteristics of these aggregates might change. Some physical, chemical and direct shear tests were performed on three gradation classes of waste tire rubber powder. The tests results were combined with data from previous studies to generate empirical relationships between cohesion, friction angle and particle size of waste tire powder rubber. A cubic (third order regression model seems to be more appropriate compared to linear and quadratic models.

  1. Raman technique application for rubber blends characterization

    Directory of Open Access Journals (Sweden)

    Smitthipong, W.

    2007-11-01

    Full Text Available Raman spectroscopy has been employed in a number of studies to examine the morphological changes in a variety of materials. It is a non-destructive analysis method and an equally useful method for the investigation of material structure. Recently, Raman spectroscopy has been developed to employ as an imaging instrumentation. Sample surface scanning in X- and Y-axis and sample depth (Z-axis can be carried out by modifying the focus of the laser beam from the Raman microscope. Therefore, three-dimensional images can be thus built by using special software. The surface and bulk properties of immiscible rubber blend were investigated by Raman spectroscopy. The results obtained by Raman spectroscopy were in good agreement with those of Scanning Electron Microscope (SEM. The combination of Raman spectrometry and SEM clearly elucidates the identification of phases between the dispersed phase and the matrix (continuous phase of the immiscible rubber blends.

  2. Crumb Rubber in cold recycled bituminous mixes

    DEFF Research Database (Denmark)

    Dondi, Giulio; Tataranni, Piergiorgio; Pettinari, Matteo;

    2014-01-01

    . Cold recycling is, among the recycling techniques, certainly the most studied and developed: it allows the recovering of bituminous material from an existing pavement without the addition of heat, whilst ensuring the creation of high quality bound base layers. A wide range of materials have been tested...... together with Reclaimed Asphalt Pavement (RAP) and, consequently, there is a large number of variables that can be considered in the mix-design process of new eco-friendly Cold Recycled Mixes. In particular, the present research involves the use of Crumb Rubber within a mixture containing 100% Reclaimed...... Asphalt Pavement, cold recycled with bitumen emulsion and cement. Two different Crumb Rubbers were adopted: one from the ambient production method, and one produced with the cryogenic process. The goal of this research project was to analyze and evaluate the different physical and mechanical...

  3. 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.

  4. 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.

  5. Quantitative Electron Tomography of Rubber Composites

    International Nuclear Information System (INIS)

    Rubber composite materials have many applications, one example being tyre manufacture. The presence of a filler material in the composite (such as carbon black or silica) causes its mechanical properties to differ in several ways when compared to pure rubber such as viscoelastic behaviour (the Payne effect), increased tensile strength and improved wear resistance. To fully understand these properties, it is necessary to characterise how the filler material is organised on the nanoscale. Using composite materials representative of those found in tyres, this work illustrates the use of electron tomography and machine learning methods as tools to describe the percolation behaviour of the filler; in this case, we focus on the largest proportion of particles absorbed into one single object as a function of particle spacing

  6. Energy recycling of plastic and rubber wastes

    International Nuclear Information System (INIS)

    Major areas for applications of plastics and rubbers are building and construction, packaging, transportation, automobiles, furniture, house wares, appliances, electrical and electronics. Approximately 20% of all the plastics produced are utilized by the building and construction industry/sup (1-3)/. Categories of polymers mostly used in the above industries include poly (vinyl chloride), polypropylene, polyethylene, polystyrene phenolics, acrylics and urethanes. Tyres and tubes are almost exclusively made up of rubbers. One third of total consumption of plastics finds applications, like films, bottles and packaging, in food-products that have a maximum life-span of two years, after which these find way to waste dumps. As the polymer industry in Pakistan is set to grow very rapidly in the near future the increase in utilization of plastic products in synchronous with the advent of computers and information technology. About 0.60 Kg per capita of waste generated daily in Lahore /(7.14)/ contains considerable quantity of plastics. (AB)

  7. Radiation Sterilization of Naturual Rubber Examination Gloves

    International Nuclear Information System (INIS)

    The sterilization dose setting by ISO 11137 method 1 was conducted for natural rubber examination gloves provided by a local factory. The suitable sterilization dose for an average product bioburden falls between 20 - 25 kilogray. Maximum dose of 25 or 50 kilogray results in no changes of tensile s and elongation at break. Samples of examination glove were irradiated using various doses between 10 - 50 kilogray. Analysis of soluble protein content using modified Lowry method was carried out and the results revealed that irradiation did not affect the decrement of soluble protein content in this case. However, thin film samples were prepared in laboratory and treated in the same procedure. The results were also the same. The results did not show any correlation. Two factors are possibly presumed : un consistency of samples and the irradiation of finished products could not affect those soluble proteins in rubber gloves

  8. Sizing solar-assisted natural rubber dryers

    Energy Technology Data Exchange (ETDEWEB)

    Pratoto, A.; Daguenet, M. [Universite de Perpignan (France). Laboratoire de Thermodynamique et Energetique; Zeghmati, B. [IUT Belfort-Montbeliard (France). Laboratoire de Metrologie des Interfaces Techniques

    1997-10-01

    Due to the lack of firewood, the use of solar energy in drying of natural rubber has been envisaged and it has been the subject of several works. The present work is concerned with the design of solar-assisted natural rubber dryers. The system performance is estimated using the average day method. The possibility of heat dumping and the configuration of the collector array are taken into account. To facilitate the user in making a rapid estimation on the collector area required, a simplified sizing method is developed. To this end, an empirical relation is performed by correlating the results of short-cut simulation to design parameters which are easily determined. (author)

  9. Compositions of Magmatic and Impact Melt Sulfides in Tissint And EETA79001: Precursors of Immiscible Sulfide Melt Blebs in Shergottite Impact Melts

    Science.gov (United States)

    Ross, D. K.; Rao, M. N.; Nyquist, L.; Agee, C.; Sutton, S.

    2013-01-01

    Immiscible sulfide melt spherules are locally very abundant in shergottite impact melts. These melts can also contain samples of Martian atmospheric gases [1], and cosmogenic nuclides [2] that are present in impact melt, but not in the host shergottite, indicating some components in the melt resided at the Martian surface. These observations show that some regolith components are, at least locally, present in the impact melts. This view also suggests that one source of the over-abundant sulfur in these impact melts could be sulfates that are major constituents of Martian regolith, and that the sulfates were reduced during shock heating to sulfide. An alternative view is that sulfide spherules in impact melts are produced solely by melting the crystalline sulfide minerals (dominantly pyrrhotite, Fe(1-x)S) that are present in shergottites [3]. In this abstract we report new analyses of the compositions of sulfide immiscible melt spherules and pyrrhotite in the shergottites Tissint, and EETA79001,507, and we use these data to investigate the possible origins of the immiscible sulfide melt spherules. In particular, we use the metal/S ratios determined in these blebs as potential diagnostic criteria for tracking the source material from which the numerous sulfide blebs were generated by shock in these melts.

  10. 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%.

  11. Characterization of crumb rubber modified by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  12. Optical Characterization of Semiconducting Natural Rubber Nanoparticles and its Composites

    Science.gov (United States)

    Neena, P.; Mathew, Anisha Mary

    2011-10-01

    The present work explains optical properties of semiconducting natural rubber nanoparticles from pristine natural rubber by doping. The studies give evidence that the SbCl5 is an efficient dopant for natural rubber. The mechanism of conduction predominantly involves the formation of conjugated sequence of unsaturated double bond in the polymer backbone. Examination of the UV/Vis study reveals the formation of charge transfer complexes in the polymer back bone. Particle filled elastomeric composites have become attractive owing to their low cost and widespread industrial applications. The arrival of nanometer fillers to polymer materials is a promising channel for their property modification. Natural rubber composite is prepared by mixing the pristine natural rubber with semiconducting natural rubber powder.

  13. Development of rubber material for high radiation field

    International Nuclear Information System (INIS)

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

  14. Research on a haptic sensor made using MCF conductive rubber

    International Nuclear Information System (INIS)

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

  15. Characterization of crumb rubber modified by gamma radiation

    International Nuclear Information System (INIS)

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

  16. 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.

  17. PENANGGULANGAN KERUSAKAN PERIODONTAL AKIBAT PEMAKAIAN RUBBER LIGATURE

    OpenAIRE

    Oktawati, Sri

    2008-01-01

    Orthodontic Treatment become more popular and interest by the people. Therefore a sufficient knowledge of dentist is very necessary. Improper planning and treatment or using unsuitable equipment will be damage periodontal tissue. If it's happened and untreated carefully as soon as possible, the teeth will fell out. A boy with eight years old got an inflammation and hardly mobility teeth (O4). The condition is happen after using orthodontic rubber ligature on overcome central diastema. Inflamm...

  18. Radiation resistant modification of silicone rubber

    International Nuclear Information System (INIS)

    For the use in the light-water nuclear power generation plants, wires and cables are required to keep flame retardancy and superior resistivity against heat and radiation throughout the whole period of service. They are expected, further, to fulfill their functions even under LOCA conditions. A new technology to give flame and radiation resistancy to insulating materials for general use in the nuclear power facilities was already reported in JAERI-M 82-057. The present study aimed subsequently to provide a method to give high radiation resistancy to dimethylsilicone rubber (DMS) which is used as highly heat resistant insulating materials (thermal tolerance, 1800C). For the improvement of radiation resistancy, the effects of polymer blending were examined by blending DMS with other rubbers, e.g., ethylene-propylene diene rubber (EPDM) or tetrafluoroethylene-propylene copolymer (Copoly (TFE-P)), which show different degradation behavior each other when exposed to radiation. After detailed experimental works, it was elucidated that the blended rubbers show higher radiation resistance (150 -- 200 Mrad) than DMS. In particular when DMS-Copoly (TFE-P) blend was incorporated with a small amount of CeO2, high heat and radiation resistivity and satisfactory electrical performance were shown in the sequential tests (heat aging (2200C, 4 days) → radiation (200 Mrad) → super heated steam (1500C, 1 day)) according to IEEE standards for simulated LOCA on wire specimen. On the other hand, DMS without any modification lost its performance as insulator by the irradiation (200 Mrad). (author)

  19. Commercial irradiation of natural rubber latex

    International Nuclear Information System (INIS)

    Cost of irradiation is one of the important factor to expand industrial application of radiation vulcanized natural rubber latex (RVNRL). The irradiation cost was studied under the RCA project, RAS/8/061/1109, and reasonable cost was reported by use of single purpose latex irradiation facility of 1500 ton/year. For a market development of RVNRL, irradiation of latex of the order of 100 ton/year may be required. Construction of the single purpose pilot plant of this scale is not commercially feasible. In this stage use of contract irradiation facilities which are familiar world wide gives a solution. Radia Industry Co., Ltd. have two irradiation facilities with 1.4 MCi of Co-60 and irradiate natural rubber latex for Okamoto Industries, Inc. with use of the incremental dose irradiator which is commonly used for sterilization of medical supplies. Natural rubber latex filled in standard 20 liter plastic bags are loaded on the hanger of trolley conveyer, and irradiated without agitation. The dose uniformity was around 2, and properties of the RVNRL was reported satisfactory. The dose uniformity can be improved if special container is applied. In future it is expected to construct a larger single purpose irradiation plant to provide low cost irradiation for multi-client, or import RVNRL from RCA countries provided transportation test is successful. We have interest in electron beam valcanization. Radia Industry Co., Ltd. put an order 5 MeV, 150 kW electron beam machine and it will be operational in 1990. High penetration of 5 MeV electron beam is useful for radiation processing in the condensed media like natural rubber latex. (author)

  20. Rubber Impact on 3D Textile Composites

    OpenAIRE

    Heimbs, Sebastian; Van Den Broucke, Björn; DUPLESSIS KERGOMARD, Yann; Dau, Frédéric; MALHERBE, Benoit

    2012-01-01

    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 o...

  1. Radiation processing of natural rubber latex

    International Nuclear Information System (INIS)

    Significant progress has been made in the last 5 years in developing new rubber material using radiation technology that holds important benefits for industries in Southeast Asia and the Pacific. A driving force behind its development has been co-ordinated research through an international programme of the IAEA and United Nations Development Programme (UNDP) known as the Regional Co-operative Agreement (RCA). The technology is called radiation vulcanization of natural rubber latex, or RVNRL. It uses high-energy gamma radiation (it also can use electron beams) to initiate vulcanization, a process that chemically bonds molecules to produce rubber elasticity and strength. As with other radiation industrial processes, products are not radioactive. In the RVNRL process, radiation energy replaces the use of a sulphur-based process and produces a material that retains all properties of the conventional product. However, it has some additional remarkable qualities: the absence of carcinogenic nitrosoamines; extremely low cytotoxicity; absence of sulphur and zinc oxide; and high transparency and softness. Rubber products for medical and hygienic uses are obviously the most promising applications of RVNRL technology because of the absence of carcinogenic and toxic products. These essential requirements are easily met by the radiation technology, and at the moment, by no other alternative. Within the technology development programme, test production of various products such as condoms, gloves, nipples, pacifiers, and toy balloons are now being carried out at different centers participating in the programme. Pilot production of condoms and gloves for medical examinations is done in Indonesia. Products are tested extensively in various field locations. Low-cost irradiators have been specifically designed for vulcanization applications, and the main parameters for estimating production costs and for conducting feasibility studies have been developed

  2. Radiation vulcanization of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    The response of Philippine natural rubber latex to irradiation vulcanization and the stability of the irradiated natural rubber latex (INRL) upon storage and aging were investigated. Commercially available high ammonia (HA) concentrated latices obtained from various rubber plantations in Mindanao island were treated with 5 phr of n-butyl acrylate (nBA), and gamma-irradiated at the PNRI 60Co irradiation facility at a dose rate of 2.57 kGy/hr. Unirradiated cast latex films gave different green strengths which varied from 2-11 MPa. Cast films from INRL exhibited maximum tensile strengths were obtained from cast films with low Mg and high nitrogen contents. Thermal analysis using thermogravimetry (TG) revealed one major decomposition product at 374o-377oC. Its rate of decomposition decreased to a minimum at 15 kGy, then increased as radiation dose was increased. This trend correlated well with the tensile strength measurements. The stability of the INRL upon storage and aging is an essential parameter to the rubbe latex industry. For storage studies, INRL was stored for various periods of time. It was found that the pH and total solids content of the stored INRL did not change significantly after 12 months of storage; the MST values remained at above 1000 seconds, and the viscosity decreased with time. The cast films exhibited a decline in tensile strength, modulus300%, and crosslinking density upon storage. While there were observed changes in the physical properties of the INRL during the storage period, the data indicate that these properties were within values acceptable to the latex industry. Tests on the aging properties of INRL films were undertaken. It was shown that among the chemical antioxidants presently used by the latex industry, TNPP demonstrated the highest antioxidant property, followed by Antage DAHQ and Vulcanox BKF. Our data indicate that the natural rubber latex produced and processed in the Philippines is suited for radiation vulcanization

  3. Evaluating permanent deformation in asphalt rubber mixtures

    OpenAIRE

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

    2009-01-01

    Permanent deformation or rutting, one of the most important distresses inflexible pavements, has long been a problem in asphalt mixtures. Throughout the years, researchers have used different test methods lo estimate the performance of asphalt mixtures in relation to rutting. One of the alternatives to reduce permanent deformation in asphalt pavement layers is through the use of mixtures produced with asphalt rubber This work aims at comparing the performance of a conventional dense graded mi...

  4. Microstructural characterisation of rubber modified asphalt mixtures

    OpenAIRE

    Abdul Hassan, Norhidayah

    2013-01-01

    Research to improve the performance of asphalt mixtures through the addition of crumb rubber using the dry process has continued worldwide because of its potential as a recycling option for used tires. For decades, dry mixed rubberised asphalt mixtures have performed inconsistently in field trials and laboratory evaluations. However, current research has revealed that the performance of asphalt mixtures is highly dependent on the characteristics of its internal structure or phase constituents...

  5. Friction of Pneumatic Rubber Tyres on Snow

    Directory of Open Access Journals (Sweden)

    H. D. Sharma

    1967-10-01

    Full Text Available The paper describes a new apparatus for determination of the friction of pneumatic rubber tyres on snow at different loads for different inflation pressures. It is found that the friction decreases with increase of tyre size. It is also noted that the friction increases with decreasing the temperature below zero degree centigrade. Friction is found dependent on density and bearing capacity of snow. The results refer only to measurements at very slow speed.

  6. MODIFYING V-14 RUBBER WITH CARBON FIBERS

    OpenAIRE

    Shadrinov N. V.; Nartakhova S. I.

    2016-01-01

    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

  7. 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. 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 w...

  8. Modification of Asphalt by the Use of Crumb Rubber

    OpenAIRE

    Shah Room; Muhammad Aleem; Muhammad Ahmad Rana; Umair Anwar Awan; Sajjad Ali

    2014-01-01

    Health aspects enforced to ponder a study on asphalt which incorporate rubber crumbs to increase strength and flexibility of asphalt. Disposal of waste tires is a menace and it’s a serious problem globally because it is not easily biodegradable as these tires consume large spaces, open burning cause serious problems. By the use of rubber tires, this scrap is utilized efficiently and reduces the cost of asphalt to produce economical system. The asphalt is absorbed by the rubber par...

  9. Comparison between asphalt rubber and conventional mixtures in overlay design

    OpenAIRE

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

    2008-01-01

    Asphalt modified with crumb rubber has been used to produce asphalt rubber mixtures for pavement overlays subjected to heavy loads and high temperatures. Under severe conditions, these mixtures are capable of resisting permanent deformations, having an extended fatigue life and resisting crack propagation in comparison to conventional ones. A laboratory research was conducted to determine the performance properties of overlays with asphalt rubber mixtures produced through wet processes using ...

  10. 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...

  11. 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...

  12. Laboratory Study on Properties of Rubber-Soils

    OpenAIRE

    Ahmed, Imtiaz

    1993-01-01

    The waste tire problem in the United States is of great magnitude and has far reaching environmental and economic implications. This study investigates the feasibility of using tire chips, alone and mixed with soils, as lightweight material in highway embankments . The report contains: synthesis of all available information and results from laboratory testing of tire chips, rubber-Ottawa sand, and rubber-Crosby till. It is found that rubber-sand with chip/mix ratios of 33% or less exhibits ex...

  13. 21 CFR 801.437 - User labeling for devices that contain natural rubber.

    Science.gov (United States)

    2010-04-01

    ... rubber, and synthetic latex or synthetic rubber that contains natural rubber in its formulation. (1) The... displayed in conformance with section 502(c) of the Federal Food, Drug, and Cosmetic Act (the act) (21...

  14. 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 .

  15. 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 .

  16. The Blue Emu

    Science.gov (United States)

    Descalzi, Doug; Gillett, John; Gordon, Carlton; Keener, ED; Novak, Ken; Puente, Laura

    1993-01-01

    The primary goal in designing the Blue Emu was to provide an airline with a cost efficient and profitable means of transporting passengers between the major cities in Aeroworld. The design attacks the market where a demand for inexpensive transportation exists and for this reason the Blue Emu is an attractive investment for any airline. In order to provide a profitable aircraft, special attention was paid to cost and economics. For example, in manufacturing, simplicity was stressed in structural design to reduce construction time and cost. Aerodynamic design employed a tapered wing which reduced the induced drag coefficient while also reducing the weight of the wing. Even the propulsion system was selected with cost effectiveness in mind, yet also to maintain the marketability of the aircraft. Thus, in every aspect of the design, consideration was given to economics and marketability of the final product.

  17. Synthesizing a Blue Ocean

    OpenAIRE

    Vester, Daniel

    2012-01-01

    The purpose of this Master thesis was to determine how electronic musical instrument companies could utilize innovation strategies to add value to their products and create new business markets beyond their core. The theoretical framework was established by outlining competitive strategies suitable for adoption by electronic musical instrument companies. The Blue Ocean Strategy was compared to traditional competitive strategies such as Porter’s Five Forces, and subsequently chosen because of ...

  18. 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.

  19. The use of radiotracers in natural rubber research in Malaysia

    International Nuclear Information System (INIS)

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

  20. Production of liquid epoxidised natural rubber (ENR) by photochemical technique

    International Nuclear Information System (INIS)

    Controlled reduction of molecular weight of solid-form epoxidised natural rubber (ENR) by a 17 photochemical technique has been studied. The product would be used for preparing rubber-based resin for radiation curing. The technique studied the effects of hydrogen peroxide on the rate of molecular weight reduction of the solid rubber as well as its combination with reducing agent such as sodium nitrite. Analysis by IR spectroscopic technique suggests the formation of hydroxyl and carbonyl groups as a result of the ring-opening of the epoxy groups of rubber. NMR as well as IR spectra show the possible formation of furan-like species. (Author)

  1. 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.

  2. 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

  3. A quinozolinone derivative as a novel rubber additive

    Energy Technology Data Exchange (ETDEWEB)

    Roy, B.C.; Khanra, T.K.; Maiti, S.; Adhikari, B. [Indian Institute of Technology, Kharagpur (India)

    1993-12-31

    A new quinozolinone derivative containing -NH and -SH functional sites has been developed as a novel antioxidant for diene rubbers. A sulfenamide derivative was prepared from the above compound which acts as an excellent accelerator cum antioxidant for natural rubber. This sulfenamide compound even when used at 50% concentration of the combined amount of commercial accelerator (CBS) and antioxidant (MBI) exhibits comparable accelerating characteristics and superior antiaging performance in the vulcanization of natural rubber. This dual function sulfenamide promises to offer better dispersion in the rubber matrix than two separate chemicals - one accelerator and the other antioxidant - used commercially.

  4. Coupled Thermo-Mechanical Analyses of Dynamically Loaded Rubber Cylinders

    Science.gov (United States)

    Johnson, Arthur R.; Chen, Tzi-Kang

    2000-01-01

    A procedure that models coupled thermo-mechanical deformations of viscoelastic rubber cylinders by employing the ABAQUS finite element code is described. Computational simulations of hysteretic heating are presented for several tall and short rubber cylinders both with and without a steel disk at their centers. The cylinders are compressed axially and are then cyclically loaded about the compressed state. The non-uniform hysteretic heating of the rubber cylinders containing a steel disk is presented. The analyses performed suggest that the coupling procedure should be considered for further development as a design tool for rubber degradation studies.

  5. Radiation vulcanization of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    The response of Philippine natural rubber latex to radiation vulcanization and the stability of the irradiated natural rubber latex (INRL) upon storage and aging were investigated. Commercially available high ammonia (HA) concentrated lattices obtained from various rubber plantations in Mindanao Island were treated with 5 phr of n-butyl acrylate (nBA), and gamma-irradiated at the PNRI sup 60 Co irradiation facility at dose rate of 2.57 KGy/hr. Unirradiated cast latex films gave different green strength which varied from 2 - 11 MPa. Cast films from INRL exhibited maximum tensile strengths of 25 - 32 MPa at a radiation dose of 15 kGy. Higher tensile strengths were obtained from cast films with low Mg and high nitrogen contents. Thermal analysis using thermogravimetry (TG) revealed one major decomposition product at 374 degree C - 377 degree C. Its rate of decomposition decreased to a minimum at 15 kGy, then increased as radiation dose increased. This trend correlated well with the tensile strength measurements. The stability of the INRL upon storage and aging is an essential parameter to the rubber latex industry. For storage studies, INRL was stored for various periods of time. It was found that the pH and total solids content of the stored INRL did not change significantly after 12 months of storage; the MST values remained at above 100 seconds, and the viscosity decreased with time. The cast films exhibited a decline in tensile strength, modulus 300% and crosslinking density upon storage. While there were observed changes in the physical properties of the IRNL during the storage period, the data indicate that these properties were within values acceptable to the latex industry. Tests on the aging properties of INRL film were undertaken. It was shown that among the chemical antioxidants presently used by the latex industry. TNPP demonstrated the highest antioxidant property, followed by Antage DAHQ and Vulcanox BKF. Our data indicate that the natural rubber latex

  6. Influence of the incorporation process of clay as filler on the properties of natural rubber and epoxidized natural vulcanized rubber

    International Nuclear Information System (INIS)

    Vulcanizates of natural rubber and epoxidized natural rubber, having clay as filler were prepared by different process. The degree of exfoliation of the clay was evaluated by X-ray analysis and mechanical properties were determined by stress-strain. The crosslink density was evaluated by swelling measurements. It could be observed that the use of epoxidized rubber improves significantly the mechanical properties of the vulcanizates. (author)

  7. Stress-strain determination in rubber-cord and rubber-metal structures by the frozen inset method

    Science.gov (United States)

    Ushakov, B. N.; Tartakover, E. I.

    1996-06-01

    The new experimental method for determination of stresses inside of real rubber, rubber-cord and rubber-metal structures using frozen insets and photoelasticity is considered. This method is based on analogy between the elasticity and viscoelasticity problems for polymers during polymerization. The photoelastic materials of cold polymerization for insets making are developed and testing technology is reported. The results of stress analysis in automobile tires under interior pressure and radial loads are presented.

  8. 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.

  9. 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

  10. Agronomic and Natural Rubber Characteristics of Sunflower as a Rubber-Producing Plant

    Science.gov (United States)

    Sunflower (Helianthus annuus L., Asteraceae) is a genus native to North American and is a potential natural rubber (NR) producing crop. The objectives of the study were to: 1) evaluate commercial sunflower cultivars to determine biomass production and how they partition biomass into leaves, stems, ...

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

    Directory of Open Access Journals (Sweden)

    Dongwei Shao

    2016-06-01

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

  12. Photopheresis with UV-A light and 8-methoxypsoralen leads to cell death and to release of blebs with anti-inflammatory phenotype in activated and non-activated lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Stadler, K. [Department for Internal Medicine 3, University Hospital Erlangen (Germany); Frey, B. [Department of Radiation Oncology, University Hospital Erlangen, Universitaetsstr. 27, 91054 Erlangen (Germany); Munoz, L.E.; Finzel, S.; Rech, J. [Department for Internal Medicine 3, University Hospital Erlangen (Germany); Fietkau, R. [Department of Radiation Oncology, University Hospital Erlangen, Universitaetsstr. 27, 91054 Erlangen (Germany); Herrmann, M. [Department for Internal Medicine 3, University Hospital Erlangen (Germany); Hueber, A. [Centre for Rheumatic Diseases, University of Glasgow (United Kingdom); Gaipl, U.S., E-mail: udo.gaipl@uk-erlangen.de [Department of Radiation Oncology, University Hospital Erlangen, Universitaetsstr. 27, 91054 Erlangen (Germany)

    2009-08-14

    Background: Extracorporeal photopheresis is a therapy for treatment of autoimmune diseases, cutaneous T-cell lymphoma, organ graft rejection as well as graft-versus-host diseases. The exact mechanism how the combination of 8-methoxypsoralen plus UV-A irradiation (PUVA) acts is still unclear. We investigated the cell death of activated and non-activated lymphocytes after PUVA treatment as well as the rate of released blebs and their antigen composition. Results: In presence of 8-MOP, UV-A light highly significantly increased the cell death of activated lymphocytes. The same was observed to a lesser extent in non-activated cells. Blebs derived from activated lymphocytes after PUVA treatment showed the highest surface exposition of phosphatidylserine. These blebs also displayed a high exposure of the antigens CD5 and CD8 as well as a low exposure of CD28 and CD86. Conclusion: PUVA treatment exerts anti-inflammatory effects by inducing apoptosis and apoptotic cell-derived blebs with immune suppressive surface composition.

  13. Our Blue Gene Experience

    Czech Academy of Sciences Publication Activity Database

    Jakl, Ondřej; Starý, Jiří

    Ostrava : Ústav geoniky AV ČR, 2009 - (Blaheta, R.; Starý, J.), s. 50-54 ISBN 978-80-86407-60-9. [SNA '09 - Seminar on numerical analysis: modelling and simulation of challenging engineering problems. Ostrava (CZ), 02.02.2009-06.02.2009] R&D Projects: GA ČR(CZ) GA105/09/1830 Institutional research plan: CEZ:AV0Z30860518 Keywords : IBM Blue Gene/P * finite element solver * parallel scalability Subject RIV: BA - General Mathematics

  14. Estruturas fundamentais no blues

    OpenAIRE

    Silva, Rafael Palmeira da

    2012-01-01

    Resumo: Esta pesquisa tem como objeto de estudo a aplicação e adaptação da teoria de Schenker como ferramenta analítica aplicada ao jazz, tendo em vista a possibilidade de encontrar estruturas fundamentais distintas na música popular. Tendo como base as análises feitas por Larson (1998; 2009), Forte (2011) e Stock (1993) a pesquisa abordará, em um primeiro momento, as origens do jazz (blues e ragtime) como parte essencial para sua abordagem analítica, através da ótica etno-schenkeriana propos...

  15. 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.

  16. Some possible uses of radioisotopes in the rubber industry

    International Nuclear Information System (INIS)

    A method is described for using beta-emitters (Tl204 and S35) for measuring the wearing qualities of motor-vehicle tyres, checking the homogeneity of tyre rubber, and non-contact thickness-gauging of rubberized fabrics. (author)

  17. Development of radiation-curable resin based on natural rubber

    International Nuclear Information System (INIS)

    A new radiation curable resin based on natural rubber has been developed. The resin was based on the reaction between low molecular weight epoxidised natural rubber and acrylic acid. When formulated with reactive monomers and photoinitiator, it solidified upon irradiation with UV light. The resin may find applications in coating for cellulosic-based substrates and pressure-sensitive adhesive

  18. Reinforcement Effect of Corn Flour in Rubber Composites

    Science.gov (United States)

    Corn flour is an economical renewable material and investigated in this study as filler for rubber composites. The composites were prepared by mixing an aqueous dispersion of corn flour with rubber latex, followed by freeze-drying and compression molding. The small strain elastic modulus and the str...

  19. Natural Rubber Quantification in Sunflower Using an Automated Solvent Extractor

    Science.gov (United States)

    Leaves of sunflower (Helianthus annuus) produce a small amount of low molecular weight natural rubber (NR) and this species has potential as a rubber-producing crop plant. Quantifying NR in plant tissue has traditionally been accomplished using Soxhlet or gravimetric methodologies. Accelerated solve...

  20. Leaching of nitroso rubber material removes uncured polymer

    Science.gov (United States)

    Bratfisch, W. A.; Gonzalez, R.

    1972-01-01

    New leaching process removes uncured polymer from nitroso rubber, elastomer used in presence of nitrogen tetroxide. Uncured portion is removed by controlled soaking of polymer slab in Freon TF. Leaching with Freon TF prevents nitroso rubber from adhering to adjoining surfaces and limiting its usefulness in either static or dynamic applications.

  1. Radiation response of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    Our earlier work has shown that the natural rubber latex (NRL) produced and processed in the Philippines is suited for radiation vulcanization. The cast films from NRL with 50% TSC exhibited maximum tensile strengths of 25-32 MPa at 15 kGy, which is the vulcanization dose or Dv. In the manufacture of dipped NRL products, certain specifications such as %TSC, protein content and tensile properties, must be met to ensure an acceptable product. For radiation vulcanization of natural rubber latex (RVNRL) to be accepted as an alternative process, it must also meet the requirements. Thus, this paper presents additional data on the radiation response of local NRL at different total solids contents (TSC), leachable proteins from NRL films as a function of dose, and the thermal activities of irradiated natural rubber latex (INRL). Different formulations of NRL showed varying tolerances to nBA. Data showed that as %TSC increases, the maximum concentration of nBA that can be added without affecting the stability of the latex decreases. The Dv increases as the %TSC increases and the nBA content decreases. This difference in response may be attributed to a lower concentration of nBA in formulations with higher %TSC. These data indicate that the parameters in the radiation treatment will be dictated by the intended applications of INRL. The thermogravimetric data showed greater stability of INRL to thermal oxidation relative to the unirradiated NRL, which correlates directly with the tensile properties of the INRL. A radiation dose of 10 kGy increased the amount of proteins leached from cast latex films. The amount of extractable proteins did not increase significantly at higher doses. The SDS PAGE analysis of the extractable proteins from unirradiated latex film showed distinct bands. An additional band at 60 Kda appeared at 10 kGy. All these bands became diffuse at higher doses, indicating the radiolysis of the proteins

  2. 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.

  3. Radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    This paper describes the experimental techniques and the results of radiation vulcanization of natural rubber latex carried out on several high ammonia latices available in the country. The efficiency of various sensitisers and stabilisers used were evaluated in terms of the gamma radiation dose required to produce the maximum tensile strengths. The extent of crosslinking of RVNRL sample films were estimated by equilibrium swelling ratio measurements. The stability of pre-irradiated and post-irradiated samples were monitored using viscosity measurements as the parameter

  4. Radiation stability of plastics and rubbers

    International Nuclear Information System (INIS)

    The accompanying bar charts have been prepared from several sources in response to many requests for information on the effect of ionising radiation on organic polymers. The bar charts give some indications of the radiation life of the three main divisions of useful organic polymers; in descending order of radiation stability, thermosets, thermoplastics and rubbers. They are based on change in mechanical properties when the materials are irradiated at room temperature in air and are applicable to #betta#, #betta#-radiation, x-rays and accelerated electrons. (author)

  5. Determination of permeating performances for rubber gloves

    International Nuclear Information System (INIS)

    The determination of permeating performances of rubber gloves used in handling radioisotope is described. The gaseous permeating coefficient Pg and the permeating capacities Qg were measured by pressure methods; As well as the Pv, Qv for vapour and the Pw, Qw for water were measured by a weight method. The permeating quantities Ga and the permeating capcities Qa for radionuclide (such as 210Po ect.) solution were measured by a permeating cup method. Some curves characterized the relationship of the permeating parameters were given in this paper

  6. 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.

  7. Improvement of hydrophilic property of rubber dipping former surface with Ni/B/TiO2 nano-composite film

    International Nuclear Information System (INIS)

    The objective of this study is to explore a method to improve hydrophilicity of the surface of formers that could be more easily dipped to produce high quality dipped rubber products. Photocatalytic TiO2 composite films were prepared by sol-gel method. Glass formers were coated with the Ni/B/TiO2 nano-composite film by dipping method and annealed at 400 °C for 1 h. Phase formation of TiO2 was characterized by XRD. Morphology of the TiO2 films was observed by using atomic force microscopy (AFM). Optical absorption of the films and degradation concentration of methylene blue had been measured employing UV-vis spectrophotometer. The hydrophilicity of the thin films was determined in terms of the contact angles of water and NR rubber latex droplets on the coated TiO2 composite films with and without UV irradiation. It was found from the experimental study that the Ni/B/TiO2 nano-composite film can improve wet-ability of the coated former surfaces, leading to enhancement of tensile strengths of the vulcanized natural rubber (NR) latex films.

  8. Radiation vulcanization of natural rubber latex sensitized with commercial gases

    International Nuclear Information System (INIS)

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

  9. Sugarcane bagasse ash: new filler to natural rubber composite

    Directory of Open Access Journals (Sweden)

    Renivaldo José dos Santos

    2014-12-01

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

  10. 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.

  11. Blue emitting undecaplatinum clusters

    Science.gov (United States)

    Chakraborty, Indranath; Bhuin, Radha Gobinda; Bhat, Shridevi; Pradeep, T.

    2014-07-01

    A blue luminescent 11-atom platinum cluster showing step-like optical features and the absence of plasmon absorption was synthesized. The cluster was purified using high performance liquid chromatography (HPLC). Electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS) suggest a composition, Pt11(BBS)8, which was confirmed by a range of other experimental tools. The cluster is highly stable and compatible with many organic solvents.A blue luminescent 11-atom platinum cluster showing step-like optical features and the absence of plasmon absorption was synthesized. The cluster was purified using high performance liquid chromatography (HPLC). Electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS) suggest a composition, Pt11(BBS)8, which was confirmed by a range of other experimental tools. The cluster is highly stable and compatible with many organic solvents. Electronic supplementary information (ESI) available: Details of experimental procedures, instrumentation, chromatogram of the crude cluster; SEM/EDAX, DLS, PXRD, TEM, FT-IR, and XPS of the isolated Pt11 cluster; UV/Vis, MALDI MS and SEM/EDAX of isolated 2 and 3; and 195Pt NMR of the K2PtCl6 standard. See DOI: 10.1039/c4nr02778g

  12. Blue ocean leadership.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2014-05-01

    Ten years ago, two INSEAD professors broke ground by introducing "blue ocean strategy," a new model for discovering uncontested markets that are ripe for growth. In this article, they apply their concepts and tools to what is perhaps the greatest challenge of leadership: closing the gulf between the potential and the realized talent and energy of employees. Research indicates that this gulf is vast: According to Gallup, 70% of workers are disengaged from their jobs. If companies could find a way to convert them into engaged employees, the results could be transformative. The trouble is, managers lack a clear understanding of what changes they could make to bring out the best in everyone. Here, Kim and Mauborgne offer a solution to that problem: a systematic approach to uncovering, at each level of the organization, which leadership acts and activities will inspire employees to give their all, and a process for getting managers throughout the company to start doing them. Blue ocean leadership works because the managers' "customers"-that is, the people managers oversee and report to-are involved in identifying what's effective and what isn't. Moreover, the approach doesn't require leaders to alter who they are, just to undertake a different set of tasks. And that kind of change is much easier to implement and track than changes to values and mind-sets. PMID:24956870

  13. Blue tits are ultraviolet tits

    OpenAIRE

    Hunt, S; Bennett, A.T.D.; Cuthill, I. C.; Griffiths, R.

    1998-01-01

    The blue tit (Parus caeruleus) has been classified as sexually monochromatic. This classification is based on human colour perception yet, unlike humans, most birds have four spectrally distinct classes of cone and are visually sensitive to wavelengths in the near-ultraviolet (300 to 400 nm). Reflectance spectrophotometry reveals that blue tit plumage shows considerable reflection of UV light. For example, the blue crest shows peak reflectance at wavelengths around 352 nm. Furthermore, the bl...

  14. Postpartum Blues and Postpartum Depression

    OpenAIRE

    Erdem Ö et al.

    2009-01-01

    Postpartum blues which is seen during the postpartum period is a transient psychological state. Most of the mothers experience maternity blues in postpartum period. It remains usually unrecognized by the others. Some sensitive families can misattribute these feelings as depression. In this article, we tried to review the characteristics of maternity blues and its differences from depression. We defined depression and presented the incidence and diagnostic criteria, of major depression as well...

  15. Detection of blebs and bullae in patients with primary spontaneous pneumothorax by multi-detector CT reconstruction using different slice thicknesses

    International Nuclear Information System (INIS)

    The aim of this study was to compare the diagnostic performances of multi-detector computed tomography (MDCT) reconstruction at two different slice thicknesses (1mm, 'high resolution' vs. 5mm, 'routine') with respect to the detection of blebs and bullae (BBs) in patients with primary spontaneous pneumothorax (PSP). Thirty-one patients underwent wedge resection of BBs (29 unilateral and 2 bilateral) for PSP from January 2010 to January 2013. Two observers assessed the presence and locations of BBs independently using high-resolution CT (HRCT) and routine CT reconstruction, and compared the sensitivities of each reconstruction method for BB detection using operative findings as a standard reference. In addition, the number of BBs in each CT image set was recorded and inter-observer agreements were evaluated. Sensitivity for the detection of BBs was significantly better for HRCT than routine CT (97.0% vs. 63.6% for observer 1 and 94.0% vs. 57.6% for observer 2, respectively, both P-values<0.001). On a per-bleb and a per-bulla basis, inter-observer agreements regarding BBs by HRCT were good and very good (k=0.66 and 0.94, respectively) and superior to those determined by routine CT (k=0.59 and 0.60, respectively). Different slice thickness reconstructions influence the diagnostic efficacy of MDCT for the detection of BBs in patients with PSP. High-resolution thin slice CT reconstruction was found to have a significantly greater sensitivity than routine thicker slice thickness reconstruction for the detection of BBs.

  16. CT findings for blebs and bullae in children with spontaneous pneumothorax and comparison with findings in normal age-matched controls

    International Nuclear Information System (INIS)

    Spontaneous pneumothorax (SPTX) is a relatively common condition. In patients with SPTX, CT has been advocated to identify blebs and bullae (BB) to help in management planning. The study was designed to assess our experience with CT evaluation for underlying BB in children with SPTX as compared to normal controls. Forty-three children (mean age 16 years, range 13-19 years) with 50 SPTX events with both chest radiographs and CT scans were reviewed. CT findings were compared with those seen in 29 age- and gender-matched controls without SPTX. The parameters evaluated included size, number, location, and ipsi-/contralateral BB; apical lines; and surgical correlation. In the study group, BB were identified in 14 imaged events (28%) (size 2.5-45 mm, one to six BB) with contralateral BB in 11 of the 14 (78.6%). All BB were confined to the apices. BB were sometimes difficult to differentiate from ''apical lines'' - a suspected normal variant seen in 28 imaged events (56%). Of blebs seen at surgery, 59% were identified on CT, and there were no false-positive CT findings. In the control group, no BB were identified but ''apical lines'' were seen in eight children (28%). BB were seen by CT in 28% of imaged events in children with SPTX and were always confined to the apices. When present, BB were commonly bilateral (78.6%). BB should not be confused with ''apical lines,'' which were not only seen in 56% of imaged events in the SPTX group but also in 28% of the normal controls. (orig.)

  17. CT findings for blebs and bullae in children with spontaneous pneumothorax and comparison with findings in normal age-matched controls

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Carolina V.A.; Donnelly, Lane F. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Warner, Brad W. [Cincinnati Children' s Hospital Medical Center, Department of Surgery, Cincinnati, OH (United States)

    2007-09-15

    Spontaneous pneumothorax (SPTX) is a relatively common condition. In patients with SPTX, CT has been advocated to identify blebs and bullae (BB) to help in management planning. The study was designed to assess our experience with CT evaluation for underlying BB in children with SPTX as compared to normal controls. Forty-three children (mean age 16 years, range 13-19 years) with 50 SPTX events with both chest radiographs and CT scans were reviewed. CT findings were compared with those seen in 29 age- and gender-matched controls without SPTX. The parameters evaluated included size, number, location, and ipsi-/contralateral BB; apical lines; and surgical correlation. In the study group, BB were identified in 14 imaged events (28%) (size 2.5-45 mm, one to six BB) with contralateral BB in 11 of the 14 (78.6%). All BB were confined to the apices. BB were sometimes difficult to differentiate from ''apical lines'' - a suspected normal variant seen in 28 imaged events (56%). Of blebs seen at surgery, 59% were identified on CT, and there were no false-positive CT findings. In the control group, no BB were identified but ''apical lines'' were seen in eight children (28%). BB were seen by CT in 28% of imaged events in children with SPTX and were always confined to the apices. When present, BB were commonly bilateral (78.6%). BB should not be confused with ''apical lines,'' which were not only seen in 56% of imaged events in the SPTX group but also in 28% of the normal controls. (orig.)

  18. 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.

  19. 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.

  20. Radiation graft modification of EPDM rubber

    Science.gov (United States)

    Katbab, A. A.; Burford, R. P.; Garnett, J. L.

    N-Vinyl pyrrolidone (NVP), 2-hydroxyethylmethacrylate (HEMA) and acrylamide (AAm) have been grafted to the surface of rubber vulcanizates based on ethylene-propylene-terpolymer (EPDM) using the simultaneous radiation method to alter surface properties such as wettability and therefore biocompatibility. The effect of monomer concentration, solvent and EPDM structural factors on the grafting behavior have been investigated. The inhibitory effect upon homopolymerization of various salts has also been evaluated for the three monomers. NVP and HEMA could be grafted onto EPDM rubber in the presence of aqueous solutions of cupric nitrate at 0.005 M and 1.0 M concentrations respectively. Aqueous solutions of Mohr's salt (ammonium ferrous sulphate) at 0.05 M not only suppressed the homopolymerization of AAm but also increased grafting yield. The percentage grafting also increased with increasing AAm concentration. A mechanism has been proposed to explain the behaviour of these monomers. The inclusion of multifunctional acrylates in additive amounts (1.0 vol%) enhanced the graft degree. Modified samples were able to be efficiently stained, allowing the depth of the graft copolymerization to be determined by light microscopy. Water was found to have an accelerating effect on the polymerization of these monomers, but methanol prevented their polymerization completely. The effect of EPDM structural factors upon degree of grafting was found to vary, depending upon the monomer type.

  1. Curing of natural rubber and epoxy adhesive

    International Nuclear Information System (INIS)

    Low molecular weight epoxy resin based on diglycidyl ether of bisphenol A was synthesized and mixed at constant percentages with natural rubber. The rubber epoxy system was cured with various types of curing agents such as ethylene diamine, maleic anhydride as well as the prepared resole phenol formaldehyde. A study of the photo-induced crosslinking of the prepared elastic adhesives and film samples was carried out by exposure to ultraviolet lamp (300 w) for 2 weeks at 20 deg. C. Samples containing ethylene diamine were cured at 25 + - 1 deg. C. for 24 h while samples containing maleic anhydride or resole phenol formaldehyde resins were thermally cured at 150-170 deg. C. for 10 min. Cured adhesive compositions were tested mechanically and physically and evaluated as wood adhesives. While hardness, chemical resistance as well as heat stability of the prepared cured film sample were investigated. The obtained data indicate that the highest epoxy resin content and the presence of resole phenol formaldehyde resin in composition improve the tensile strength and adhesion properties on wood. While their cured film sample have the best hardness properties, chemical resistance and heat stability. (author)

  2. 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.

  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. Instant BlueStacks

    CERN Document Server

    Judge, Gary

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A fast-paced, example-based approach guide for learning BlueStacks.This book is for anyone with a Mac or PC who wants to run Android apps on their computer. Whether you want to play games that are freely available for Android but not your computer, or you want to try apps before you install them on a physical device or use it as a development tool, this book will show you how. No previous experience is needed as this is written in plain English

  5. 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.

  6. Accelerated Thermal Aging Studies on Natural Rubber in Seismic Isolation Bearings

    International Nuclear Information System (INIS)

    Most rubbers harden and eventually become brittle owing to the aging process. The thermal aging is known to be the most significant factor in the deterioration of rubber materials. The ambient temperature substantially increases the stiffness and damping of the rubber bearings, even at room temperature. Under low temperature, a long duration of exposure increases both quantities. High temperatures have a significant effect on the mechanical properties of rubber bearings. This study focuses on the aging behavior of natural rubber material used in seismic isolation bearings by accelerated heat exposure tests. Accelerated thermal aging tests were carried out for a natural rubber material, and its lifetime was predicted. The deterioration of the rubber material is more significant at high ambient temperature. In addition, the deterioration of rubber influences the adhesion between the rubber and the steel plates. Dynamic properties of the rubber will be a critical factor for defining the service time of seismic isolation bearings

  7. 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.

  8. 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.

  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. Failure mechanisms in thin rubber sheet composites under static solicitation

    Directory of Open Access Journals (Sweden)

    E. Bayraktar

    2007-03-01

    Full Text Available Purpose: Mechanical behaviour and damage mechanisms in thin rubber sheet composites were investigated under static solicitation at room temperature. Two types of rubber are used in this study; Natural rubber, NR vulcanised and reinforced by carbon black and Synthetic rubber (styrene-butadiene-rubber, SBR.Design/methodology/approach: A comprehensive study has been carried out in order to identify a threshold criterion for the damage mechanism to explain a tearing criterion for the concept of tearing energy of the elastomers and also to give a detail for the damage mechanism depending on the loading conditions. A typical type of specimen geometry of thin sheet rubber composite materials was studied under static tensile tests conducted on the smooth and notched specimens with variable depths. In this way, the effects of the plane stress on the damage mechanism are characterized depending on the rubber materials.Findings: Damage mechanisms during tensile test have been described for both of rubber types and the criteria which characterize the tearing resistance, characteristic energy for tearing (T was explained. Damage in the specimens were evaluated just at the beginning of the tearing by means of the observations in the scanning electron microscopy (SEM.Practical implications: A tearing criterion was suggested in the case of simple tension conditions by assuming large strain. In the next step of this study, a finite element analysis (FEA will be applied under the same conditions of this part in order to obtain the agreement between experimental and FEA results.Originality/value: This study propses a threshold criterion for the damage just at the beginning of the tearing for thin sheet rubber composites and gives a detail discussion for explaining the damage mechanisms by SEM results. This type of study gives many facilities for the sake of simplicity in industrial application.

  11. 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.

  12. 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

    Cold recycling technique represents the most environmental friendly solution for pavement rehabilitation nowadays. In fact, this technique allows the use of the highest percentage of reclaimed asphalt avoiding the energy consumption related to aggregates heating required by the traditional hot mix...... 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...... the valorization of recycled materials together with the goal of achieving high performance. In the present research project, two different gradations of crumb rubber, processed with the traditional grading method, have been adopted for the production of a cold recycled mixture stabilized with bitumen emulsion...

  13. Studies on Microbial Degradation of Natural Rubber Using Dilute Solution Viscosity Measurement and Weight Loss Techniques

    OpenAIRE

    G. N. Onyeagoro; E. G. Ohaeri; U. J. Timothy

    2012-01-01

    Reduction of molecular weight of rubber polymers for easy absorption of compounding ingredients is critical in every rubber compounding operation. Yet, rubber mastication which is the current practice of achieving this is expensive, requiring high energy and equipment cost. To address this problem, microbial degradation of natural rubber (NR) and waste rubber tire (WRT) by Nocardia sp. strain 385A was studied using dilute solution viscosity measurement and weight loss methods. Solutions of NR...

  14. Effect of cryogenic and ambient crushed rubber on the mechanical properties of hot mixes asphalts

    OpenAIRE

    Neto, Silvrano Adonias Dantas; Farias, Márcio Muniz de; Pais, Jorge C.

    2009-01-01

    The crumb rubber used to produce asphalt rubber binders can be obtained either through the ambient grinding or the cryogenic processes. The final product obtained usually presents significant differences which influence the physical properties of asphalt rubber binders and, consequently, the mechanical properties of the asphalt rubber hot mixes produced with these modified binders. The objective of the study presented in this paper is to learn about the influence that the type of crumb rubber...

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

    OpenAIRE

    A. A. El-Wakil

    2011-01-01

    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 natu...

  16. 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-...

  17. 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...

  18. Radiation facility for vulcanization of synthetic leather and rubbers

    International Nuclear Information System (INIS)

    Advisability of applying γ-radiation and accelerated electrons in fabrication of rubber technical products is considered. Advantages and shortcomings of using installations with γ-sources and electron accelerators in fabrication of rubber technical products are pointed out. Specifications are given, design and performance of specially developed pilot-plant equipment for vulcanization of synthetic leather and rubbers with ELV-2 electron accelerator, are described. The equipment permits to carry out and optimize the process of radiation vulcanization in a continuous regime in a general processing line

  19. 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.

  20. Impact tests on rubber compression springs for airplane landing gears

    Science.gov (United States)

    Hohenemser, K

    1930-01-01

    The present report gives the results of tests which were made for the purpose of solving the problem of whether diagrams obtained from pressure tests could be conclusive for the determination of the safe impact coefficients. It is first established that the rubber rings adhere firmly to the compression surfaces during deformation. Suggestions are thus obtained for a constructive simplification of the rubber rings. The hysteresis phenomenon is ascribed to external and internal friction forces. A device for falling tests is then described with which the process of shock absorption with rubber rings was tested.

  1. 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.

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

    International Nuclear Information System (INIS)

    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

  3. Radiation crosslinking of styrene–butadiene rubber containing waste tire rubber and polyfunctional monomers

    International Nuclear Information System (INIS)

    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. - Highlights: • The effect of γ radiation on SBR blended with waste tire rubber was studied. • Two polyfunctional monomers were used to increase the crosslinking. • Mechanical properties of the blends were increased with absorbed dose. • TMPTA containing blend showed higher tensile strength and thermal stability. • Comparison with sulfur crosslinking was also done

  4. 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.

  5. Effect of Nanoclay on Natural Rubber Microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Carretero-Gonzalez,J.; Retsos, H.; Verdejo, R.; Toki, S.; Hsiao, B.; Giannelis, E.; Lopez-Manchado, M.

    2008-01-01

    The inclusion of highly anisotropic clay nanoparticles (nanoclays) in cross-linked natural rubber (NR) provides a more homogeneous distributed network structure and induces an early onset as well as enhancement of crystallization under uniaxial deformation. The molecular structure of the polymer network and its morphological changes during deformation were characterized by using broadband dielectric spectroscopy and in situ synchrotron wide-angle X-ray diffraction, respectively. It was found that the presence of nanoclay introduces a dual crystallization mechanism due to the alignment of nanoparticles during stretching. The improved properties in NR-nanoclay nanocomposites can be attributed to both microstructural and morphological changes induced by nanoclay as well as to the nanoclay mobility in the NR matrix during crystallization. The interplay of these factors during deformation contributes to the formation of a supernetwork structure containing cross-linked chemical chains, nanofiller, and crystallizable networks with similar length scales.

  6. Thermal stability of radiation vulcanized EPDM rubber

    International Nuclear Information System (INIS)

    Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) have been used to study the thermal stability of gamma- ray vulcanized ethylene-propylene diene rubber (EPDM) stabilized with various types of antioxidants. The antioxidants used were penta erythrityl tetrakis(3,5- di-tert-butyl(-4-hydroxyphenyl)propionate (Irganox 1010), Irganox 1035, Irganox 1520 D, as primary antioxidants; Irganox B 561 and Irganox B 900, as synergistic blends; hindered amine light stabilizer (HALS), i.e. Tinuvin 622 LD; N-isopropyl-N-phenyl-p-phenylene diamine (IPPD) and Trimethyl quinoline (TMQ) and their mixtures. The measurements were carried out under atmospheric conditions. The effect of antioxidant type, selected concentration and mechanism of reaction were determined

  7. 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.

  8. Improved styrene butadiene rubber by radiation processing

    International Nuclear Information System (INIS)

    Premature failure of elastomeric materials used in US Army tank components such as track pads, bushings, and roadwheels occurs through age, wear, hardening and cracking, softening by solvents, or permanent deformation by compression set. Millions of dollars are spent annually in effort, materials, and maintenance costs. A combination of a sulfur precure during molding and an electron beam postcure of SBR has shown to be an effective method for the manufacture of much improved vulcanizates. This work demonstrates their greater hot tear strength, as well as exceptional resistance to attack by ozone. It is also shown that the rubber has 10 times the resistance to crack initiation and less than one-third the crack growth. US Army field tests on the SBR pads for M60 tanks demonstrates their clear superiority over conventional sulfur-cured SBR

  9. Energy functions for rubber from microscopic potentials

    Science.gov (United States)

    Johal, A. S.; Dunstan, D. J.

    2007-04-01

    The finite deformation theory of rubber and related materials is based on energy functions that describe the macroscopic response of these materials under deformation. Energy functions and elastic constants are here derived from a simple microscopic (ball-and-spring) model. Exact uniaxial force-extension relationships are given for Hooke's Law and for the thermodynamic entropy-based microscopic model using the Gaussian and the inverse Langevin statistical approximations. Methods are given for finding the energy functions as expansions of tensor invariants of deformation, with exact solutions for functions that can be expressed as expansions in even powers of the extension. Comparison with experiment shows good agreement with the neo-Hookean energy function and we show how this derives directly from the simple Gaussian statistical model with a small modification.

  10. 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

  11. 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.

  12. System identification methods for metal rubber devices

    Science.gov (United States)

    Zhang, B.; Lang, Z. Q.; Billings, S. A.; Tomlinson, G. R.; Rongong, J. A.

    2013-08-01

    Metal rubber (MR) devices, a new wire mesh material, have been extensively used in recent years due to several unique properties especially in adverse environments. Although many practical studies have been completed, the related theoretical research on metal rubber is still in its infancy. In this paper, a semi-constitutive dynamic model that involves nonlinear elastic stiffness, nonlinear viscous damping and bilinear hysteresis Coulomb damping is adopted to model MR devices. The model is first approximated by representing the bilinear hysteresis damping as Chebyshev polynomials of the first kind and then generalised by taking into account the effects of noises. A very efficient systematic procedure based on the orthogonal least squares (OLS) algorithm, the adjustable prediction error sum of squares (APRESS) criterion and the nonlinear model validity tests is proposed for model structure detection and parameter estimation of MR devices for the first time. The OLS algorithm provides a powerful tool to effectively select the significant model terms step by step, one at a time, by orthogonalising the associated terms and maximising the error reduction ratio, in a forward stepwise manner. The APRESS statistic regularises the OLS algorithm to facilitate the determination of the optimal number of model terms that should be included into the model. And whether the final identified dynamic model is adequate and acceptable is determined by the model validity tests. Because of the orthogonal property of the OLS algorithm, the selection of the dynamic model terms and noise model terms are totally decoupled and the approach also leads to a parsimonious model. Numerical ill-conditioning problems which can arise in the conventional least squares algorithm can be avoided as well. The methods of choosing the sampling interval for nonlinear systems are also incorporated into the approach. Finally by utilising the response of a cylindrical MR specimen, it is shown how the model

  13. Blue-sky thinking

    International Nuclear Information System (INIS)

    Global environmental problems - such as the greenhouse effect, the depletion of natural resources and the accumulation of wastes - have been recognized as common international issues affecting humanity since the 1990s. Sustainable development on a global scale is now sought, for instance, with the establishment of the targets for greenhouse gas reduction in the 1997 Kyoto Protocol, and with the adoption of the Declaration on Sustainable Development at the 2002 Johannesburg Summit. Honda launched the slogan 'Blue Sky for Children' in the 1960s when environmental pollution became a highly visible issue. During that decade we started an aggressive approach aimed at substantial environmental improvement, and unveiled the Compound Vortex Controlled Combustion (CVCC) engine - which used unique low-emission technology - in the United States and Japan. Since then, we have developed the Variable Valve Timing and Lift Electric Control System (VTEC) and the i-VTEC series with innovative engine technology, permitting global production of vehicles that combine high performance with state-of-the-art low-emission technologies. And we continued to work to preserve the global environment by releasing a hybrid vehicle, the Insight, which achieved the most efficient fuel consumption in the world at the time of its introduction in 1998

  14. Blue Angel for green electronics

    Energy Technology Data Exchange (ETDEWEB)

    Boettcher-Tiedemann, C.; Jacobs, B. [Federal Environmental Agency, Berlin (Germany)

    2004-07-01

    The Blue Angel was the first eco-label worldwide. It has been in existence for 26 years. For the last 12 years, modern electronic office and communications equipment has been among the products that are eligible for award of the Blue Angel. The Blue Angel eco-label is an important element of integrated product policy and is aimed towards environmentally sound product design. In addition, health aspects are increasingly being taken into account in criteria development. The use of the label gives innovative companies better market opportunities for products so labelled. For consumers and for purchasers in businesses and public administrations, it gives valuable guidance for product purchase. (orig.)

  15. Amplitude-temperature analysis of hard rubber by torsional vibration

    Czech Academy of Sciences Publication Activity Database

    Šulc, Petr; Pešek, Luděk; Bula, Vítězslav; Cibulka, Jan; Košina, Jan

    2016-01-01

    Roč. 821, č. 2016 (2016), s. 295-302. ISSN 1660-9336 Institutional support: RVO:61388998 Keywords : hard rubber * torsion vibration * finite deformation * parameter identification Subject RIV: BI - Acoustics

  16. 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...

  17. 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...

  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. 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...

  20. Rubber Characterization with Fatigue and Crack Growth Analysis

    Science.gov (United States)

    Perier, Laurent; Favier, Arnaud

    2010-06-01

    Dynamic Mechanical Analysis brings advanced capabilities to generate quantitative dynamic property data of rubber compounds for modelers and end users. Additionally to the recognized DMA testing benefits, a new METRAVIB Analyzer DMA+300 includes new testing solutions for analyzing rubbers mechanical property data under extended testing conditions closer to the real product's life conditions. The DMA+300 is specifically designed and dimensioned for fatigue tests on elastomers and crack growth tests. Combined with new MULTITEST software, DMA+300 makes possible to generate multi harmonics excitation and to control the application of a specific wave form to the specimen of rubber. This paper presents the main benefits available with this machine in the domain of rubber and elastomer applications.

  1. 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...

  2. 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.

  3. 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 Rubber[HTML_REMOVED]TM[HTML_REMOVED] films. In support of NASA's Vision...

  4. 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...

  5. 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.

  6. 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.

  7. Geotechnical Properties of Rubber Tires and Sediments Mixtures

    OpenAIRE

    Sellaf, H.; H. Trouzine; M. Hamhami; Asroun, A.

    2014-01-01

    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-unlo...

  8. Complex processing of rubber waste through energy recovery

    OpenAIRE

    2015-01-01

    This article deals with the applied energy recovery solutions for complex processing of rubber waste for energy recovery. It deals specifically with the solution that could maximize possible use of all rubber waste and does not create no additional waste that disposal would be expensive and dangerous for the environment. The project is economically viable and energy self-sufficient. The outputs of the process could replace natural gas and crude oil products. The other part of the pro...

  9. 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.

  10. 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.

  11. Evaluation of asphalt-rubber membrane field performance

    Science.gov (United States)

    Shuler, S.; Gallaway, B. M.; Epps, J. A.

    1982-05-01

    This report presents a record of asphalt-rubber membrane field performance in Texas. An evaluation of performance is presented for forty-five separate projects in thirteen state highway districts. Approximately 850 lane miles of highways are represented by materials constructed as stress absorbing membranes (asphalt-rubber seal coats beneath asphalt concrete overlay). All projects reviewed were constructed between June, 1976 and September, 1981.

  12. New experimental methods to monitor and characterize asphalt rubber binders

    OpenAIRE

    Peralta, J.; Silva, Hugo Manuel Ribeiro Dias da; Pais, Jorge C.

    2010-01-01

    The need for continuous quality improvement of the road pavements, leads to the development of new binders, such as asphalt rubber (AR). AR is produced by the digestion of crumb rubber from used tires on bitumen. The resulting AR is a heterogeneous material with high viscosity. The study of this product during its production is essential due to the sudden and sharp increase in the volume of AR in this phase. Knowledge of the extent of this phenomenon has obvious implications in...

  13. An Example of a Human Topological Rubber Glove Act

    Science.gov (United States)

    Chai Toong, Yock; Yung Wang, Shih

    1997-04-01

    A hitherto unreported human body narcissistic inversion which is an example of the rubber glove act has been uncovered from a Chinese acrobatic performance. This inversion is related to the unimolecular enantiomerizations of chiral molecules, a topological figure and a rubber glove via chiral pathway. The possible mechanism of enantiomerization of an unknown cyclopolypetide based on this finding is suggested. The importance of chemical topology in biomolecules is stressed.

  14. Identification of Swelling cause on Rubber Gaskets

    OpenAIRE

    Fagerland, Jenny

    2011-01-01

    The aim of this master thesis was to develop an analysis method which identifies the swelling cause of EPDM rubber gaskets. The method shall facilitate failure investigation of rubber gaskets used in plate heat exchangers which require both determinations of volatile and involatile compounds as well as polar and non-polar compounds. To achieve this goal a combination analysis method of Headspace Gas chromatography Mass spectrometry (GC-MS) and liquid-liquid extraction Fourier Transform Infrar...

  15. Mycorrhizae on dipterocarps in rubber agroforests (RAF) in Sumatra

    OpenAIRE

    Tata, M.H.L.

    2008-01-01

    In tropical lowland forests, which dominated by trees of Dipterocarpaceae family, trees and fungi are strongly linked, through ectomycorrhiza (EcM) formation. However, as part of rapid deforestation and forest transformation, mixed dipterocarp forests have been replaced by other vegetation and land use types. Considerable areas of the lowland tropical forest in Sumatra have been turned into Rubber Agroforests (RAF). RAF is a land use type in which rubber trees are planted, while allowing spon...

  16. Preparation, thermal and flow properties of epoxidised natural rubber

    OpenAIRE

    Nakason, C.; Sainumsai, W.; Kaesaman, A.; Klinpituksa, P.

    2001-01-01

    Epoxidised natural rubber (ENR) was prepared using high ammonia concentrated latex, performic acid and non-ionic surfactant (Emulwin W). The presence and quantity of epoxide groups in the natural rubber molecules were analysed using infrared spectroscopy. The characteristic peaks of epoxide groups at the wave numbers 870 and 1140 cm-1 were observed. The quantities of epoxide groups were found to depend on reaction temperature and reaction time. Glass transition temperature (Tg) of epoxidised ...

  17. 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.

  18. FEA based Dissipation Energy and Temperature Distribution of Rubber Bushing

    Directory of Open Access Journals (Sweden)

    Zhengui Zhanga ,

    2016-01-01

    Full Text Available Rubber bushings used in the vehicle or aerospace can reduce the noise and vibration and absorb the shocks. The heat accumulation in the rubber components is attributed to the nonlinear mechanical behavior of rubber and leads to degeneration of mechanical properties. The viscoelastic damping is treated as the major mechanism of dissipation energy, which is heat source of temperature rising in bushing. A finite element method is expanded from elastic structure to viscoelastic structure and computes the dissipation energy distribution in the rubber core. Based on that heat source, the temperature distribution of rubber bushing under radial harmonic excitation has been calculated using finite volume method. The frequency and amplitude effect on dissipation energy and temperature distribution are described. The radial dynamic testing is carried out and the temperature is recorded using thermal imager to evaluate the simulation. As complement, the dynamic torsional testing is also carried out explore the possible failure zone of rubber bushing under different types of loading.

  19. 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.

  20. Fossil rubber in brown coal deposits: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Mahlberg, P.G.; Stoerr, M. (Indiana University, Bloomington (USA))

    1989-01-01

    Fossil rubber strands of middle Eocene from Geiseltal and Harpke brown coal deposits in the GDR are angiospermous remains of the branched nonarticulated laticifer cell. The cis-1,4-polyisoprene rubber was cribriform in appearance indicating possibly that it polymerized around protoplasmic components during fossilization. Cell morphology and thermal analyses of rubber hydrocarbons indicate that the deposits were not subjected to high pressure or temperatures during fossilization. The similarity of profiles for hydrocarbons extractable only from the rubber indicates their presence in the original living cell and identifies the samples to be derived from the same species. Sulfur accumulated nearly all as organic sulfur to higher levels in the rubber than in the gel. Morphological and chemical data show the laticifer to be a highly specialized cell already in the Eocene and provide new insight for interpreting the age of Angiosperms. Presence of predominantly organic sulfur with greater deposition in rubber than gel indicates the unique environmental condition related to sulfur deposition and provides the basis for a better understanding of sulfur fixation in brown coal. 23 refs., 12 figs., 2 tabs.

  1. Application of asphalt rubber technology to recreational trails

    Science.gov (United States)

    Ni, Haifeng

    Crumb rubber aggregate was employed instead of stone/sand aggregate in asphalt pavement that was modified by fine rubber particles. Crumb rubber aggregate forms an elastic network in the asphalt, which improves the pavement's susceptibility to low-temperature cracking, and absorb more stress at the crack tips than the conventional asphalt pavement. Laboratory tests were conducted to evaluate the tension/compression performance of a blend of asphalt rubber with rubber aggregate (ARRA). An optimum design methodology was introduced by examining the effect of asphalt source, curing temperature, curing time, rubber content, aggregate size, compaction pressure, and the effect of certain additives. At ambient temperature, the ARRA with equal amount of binder and aggregate exhibits good mechanical properties. Vestenamer helps improve the pavement's strength, stiffness, and fracture resistance to low temperature cracking. It was demonstrated that such pavement meets the mechanical requirements for recreational trails, such as bicycle, or pedestrian trails. ARRA is a viscoelastic material which exhibits time-dependent and loading rate-dependent behavior. Temperature is a key issue to its response to an external load. Both temperature and rate dependences were investigated. A series of uniaxial compression relaxation tests on ARRA or Vestenamer modified ARRA were conducted at room temperature to study the time-dependent performance of ARRA. Schapery's theory was applied to characterize the nonlinear viscoelastic behavior of ARRA.

  2. General theory of frictional heating with application to rubber friction

    Science.gov (United States)

    Fortunato, G.; Ciaravola, V.; Furno, A.; Lorenz, B.; Persson, B. N. J.

    2015-05-01

    The energy dissipation in the contact regions between solids in sliding contact can result in high local temperatures which may strongly effect friction and wear. This is the case for rubber sliding on road surfaces at speeds above 1 mm s-1. We derive equations which describe the frictional heating for solids with arbitrary thermal properties. The theory is applied to rubber friction on road surfaces and we take into account that the frictional energy is partly produced inside the rubber due to the internal friction of rubber and in a thin (nanometer) interfacial layer at the rubber-road contact region. The heat transfer between the rubber and the road surface is described by a heat transfer coefficient which depends on the sliding speed. Numerical results are presented and compared to experimental data. We find that frictional heating results in a kinetic friction force which depends on the orientation of the sliding block, thus violating one of the two basic Leonardo da Vinci ‘laws’ of friction.

  3. General theory of frictional heating with application to rubber friction

    International Nuclear Information System (INIS)

    The energy dissipation in the contact regions between solids in sliding contact can result in high local temperatures which may strongly effect friction and wear. This is the case for rubber sliding on road surfaces at speeds above 1 mm s−1. We derive equations which describe the frictional heating for solids with arbitrary thermal properties. The theory is applied to rubber friction on road surfaces and we take into account that the frictional energy is partly produced inside the rubber due to the internal friction of rubber and in a thin (nanometer) interfacial layer at the rubber-road contact region. The heat transfer between the rubber and the road surface is described by a heat transfer coefficient which depends on the sliding speed. Numerical results are presented and compared to experimental data. We find that frictional heating results in a kinetic friction force which depends on the orientation of the sliding block, thus violating one of the two basic Leonardo da Vinci ‘laws’ of friction. (paper)

  4. 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.

  5. Karner Blue Butterfly Recovery Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This recovery plan has been prepared by the Karner Blue Butterfly Recovery Team under the leadership of Dr. David Andow, University of Minnesota-St. Paul. Dr. John...

  6. 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.

  7. Blue Ocean vs. Five Forces

    OpenAIRE

    Burke, Andrew; Stel, André; Thurik, Roy

    2010-01-01

    textabstractThe article reports on the authors' research in the Netherlands which focused on a profit model in Dutch retail stores and a so-called blue-ocean approach which requires a new market that attracts consumers and increases profits. Topics include the competitive strategy approach to increasing profits. The authors conclude that the blue-ocean strategy or innovation approach is sustainable.

  8. From shifting agriculture to sustainable rubber agroforestry systems (jungle rubber) in Indonesia: a history of innovations processes.

    OpenAIRE

    Penot, Eric,

    2004-01-01

    The aim of this chapter is to describe changes in the Indonesian jungle rubber system from the angle of the production of innovation by farmers themselves (indigenous knowledge) and the process of integration of external technical innovations in an overall process of creation of innovation. In other words, the integration of indigenous knowledge at different stages of history with rubber has enabled, and continues to enable farmers to rely on the sustainable cropping and farming systems repre...

  9. 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...

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

    Science.gov (United States)

    Przepiórkowska, A; Chrońska, K; Zaborski, M

    2007-03-01

    The noxious wastes from the tanning industry such as chrome-tanned leather shavings were used as the only filler of rubber mixes containing carboxylated butadiene-acrylonitrile rubber (XNBR) or butadiene-acrylonitrile rubber (NBR), and a dispersing agent Limanol PEV (Schill & Seilacher). The best form addition of leather powder to the rubber mixes is mixed the waste protein with zinc oxide. The leather powder added to the rubber mixes improves the mechanical properties: tensile strength (T(s)), elongation at break (epsilon(b)) and increase the cross-linking density of carboxylated XNBR and NBR rubber mixes. Satisfactory results of these studies are presented in this work. PMID:16942836

  11. 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.

  12. Wortmannin induces MCF-7 breast cancer cell death via the apoptotic pathway, involving chromatin condensation, generation of reactive oxygen species, and membrane blebbing

    Directory of Open Access Journals (Sweden)

    Akter R

    2012-07-01

    Full Text Available Rozina Akter,1 Md. Zakir Hossain,2 Maurice G Kleve,3 Michael A Gealt31Applied Biosciences Emphasis, Department of Applied Science, 2Graduate Institute of Technology, 3Department of Biology, College of Science and of Mathematics, University Arkansas at Little Rock, Little Rock, AR, USABackground: Apoptosis can be used as a reliable marker for evaluating potential chemotherapeutic agents. Because wortmannin is a microbial steroidal metabolite, it specifically inhibits the phosphatidyl inositol 3-kinase pathway, and could be used as a promising apoptosis-based therapeutic agent in the treatment of cancer. The objective of this study was to investigate the biomolecular mechanisms involved in wortmannin-induced cell death of breast cancer-derived MCF-7 cells.Methods and results: Our experimental results demonstrate that wortmannin has strong apoptotic effects through a combination of different actions, including reduction of cell viability in a dose-dependent manner, inhibition of proliferation, and enhanced generation of intracellular reactive oxygen species.Conclusion: Our findings suggest that wortmannin induces MCF-7 cell death via a programmed pathway showing chromatin condensation, nuclear fragmentation, reactive oxygen species, and membrane blebbing, which are characteristics typical of apoptosis.Keywords: wortmannin, human breast adenocarcinoma, apoptosis, reactive oxygen species, flow cytometry

  13. Maillard Reaction in Natural Rubber Latex: Characterization and Physical Properties of Solid Natural Rubber

    OpenAIRE

    Montha, S.; P. Suwandittakul; A. Poonsrisawat; Oungeun, P.; Kongkaew, C.

    2016-01-01

    Maillard reaction in Natural Rubber (NR) latex was investigated by treating fresh NR latex with glutaraldehyde (C5H8O2) in amounts of 0, 50, 100, and 200 mmol/kg of latex. Protein cross-linking in fresh NR latex and solid NR was confirmed by using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and attenuated total reflection infrared (ATR-IR) spectroscopy, respectively. It was found that degree of protein cross-linking in NR increased with increasing C5H8O2 concentration....

  14. 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. PMID:24621374

  15. Characterisation of biodiversity in improved rubber agroforests in West-Kalimantan, Indonesia. Real and Potential uses for spontaneous plants

    OpenAIRE

    Diaz-Novellon, S.; Penot, E.,; Arnaud, M.

    2004-01-01

    Since the introduction of rubber at the turn of the 20th century smallholders have developed an original complex agroforestry system called jungle rubber in which non selected young rubber trees (seedlings) are managed extensively alongside secondary forest re-growth. The issue of improving smallholder rubber productivity at affordable capital investments and levels of inputs while maintaining the environmental benefits of jungle rubber has been addressed by the Smallholder Rubber Agroforestr...

  16. Quantification of the effects of crumb rubber in CRM binders

    Science.gov (United States)

    Putman, Bradley James

    Since the mid-1960s, crumb rubber has been used to modify asphalt binders. The crumb rubber, also referred to as crumb rubber modifier (CRM), is produced by grinding scrap tires into fine powders with particulate sizes generally smaller than 2 mm. In most cases, CRM is incorporated into binder using the "wet" method, where the crumb rubber is blended with the asphalt binder. The binder modification that occurs during this blending process is physical in nature, where the lighter oils of the binder diffuse into the CRM particles. As the rubber particles absorb the oils, the particles swell; therefore, increasing the viscosity and stiffness of the CRM binder. This research evaluated the viscosity and complex shear modulus (G*) of 36 different laboratory-produced CRM binder combinations (two CRM processing methods, two CRM contents, three CRM sizes, and three binder sources) and three base binders. From this investigation, a method was developed to quantify the effects of the crumb rubber modification. These effects were identified as the interaction effect (IE) resulting from the diffusion of the lighter binder factions into the rubber particles and the particle effect (PE), which is the result of the change in the rheological properties due to the filling effect of the particulate CRM. Following statistical analyses of the results, it was determined that CRM binders had greater viscosity and complex shear modulus (G*) values than the base binders. These values increased with CRM content. The CRMs having higher surface area (i.e., ambient ground and finer CRM) generally had higher IE values, while the PE generally increased with particle size. HP-GPC testing indicated that the CRM binders also had higher large molecular size (LMS) fractions and lower small molecular size (SMS) fractions as determined from the HP-GPC profiles. As the LMS increased and the SMS decreased, the IE increased. Two of the three binder sources followed this trend, indicating that those

  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. About the cure kinetics in natural rubber/styrene Butadiene rubber blends at 433 K

    Energy Technology Data Exchange (ETDEWEB)

    Mansilla, M.A., E-mail: mmansilla@df.uba.ar [Laboratorio de Polimeros y Materiales Compuestos, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1, C1428EGA Buenos Aires (Argentina); Marzocca, A.J. [Laboratorio de Polimeros y Materiales Compuestos, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1, C1428EGA Buenos Aires (Argentina)

    2012-08-15

    Vulcanized blends of elastomers are employed in several goods mainly to improve physical properties and reduce costs. One of the most used blends of this kind is that composed by natural rubber (NR) and styrene butadiene rubber (SBR). The cure kinetic of these blends depends mainly on the compound formulation and the cure temperature and time. The preparation method of the blends can influence the mechanical properties of the vulcanized compounds. In this work the cure kinetic at 433 K of NR/SBR blends vulcanized with the system sulfur/TBBS (N-t-butyl-2-benzothiazole sulfenamide) is analyzed in samples prepared by mechanical mixing and solution blending. The two methods produce elastomer domains of NR and SBR, which present different microstructure due to the cure level attained during vulcanization. The cure kinetics is studied by means of rheometer tests and the model proposed by Kamal and Sourour. The analysis of the cure rate is presented and is related to the structure obtained during the vulcanization process.

  19. Some Tribological Characterization of “EPDM” Rubber

    Directory of Open Access Journals (Sweden)

    A. Mukhopadhyay

    2014-06-01

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

  20. Bitumen-rubber mixture for effective vibration damping sheet

    Directory of Open Access Journals (Sweden)

    V.D. Cherkasov

    2013-12-01

    Full Text Available The results of researches of a bitumen-rubber mixture design for the damping sheet are presented. Application of vibration damping sheet in thin-walled construction designs allows reducing negative vibrations considerably. Existent bituminous and bituminous-rubber materials have insufficient vibration damping in the range of negative temperatures that is inadmissible in Russian climate conditions. Selection of structure bitumen-rubber mixture and regularity establishment of its properties will allow receiving a material with a wide temperature range of application. As an object of research there was chosen the polymeric matrix representing a mix of two materials – butyl rubber and bitumen, plasticized by industrial oil I-20A; the filler – swept of MTD-2 brands. The dependence of physical and mechanical properties of a material on the contents of bitumen-butyl rubber in a mix was established. The material based on the received mixture has effective vibration damping in the range of temperatures from -40 to +40 °C.

  1. Degrading radiation effects on properties of bromobutyl rubber compounds

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  2. No pain relief with the rubber hand illusion.

    Directory of Open Access Journals (Sweden)

    Rahul Mohan

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

  3. Three dimensional base isolation system on laminated thick rubber bearings

    International Nuclear Information System (INIS)

    In order to reduce horizontal and vertical earthquake response of internal equipments in the nuclear power plants, we evaluated the performance of three dimensional base isolation system using laminated thick rubber bearings. From the loading test of scaled model of laminated thick rubber bearing, it was found that the natural rubber bearing was able to be extended to thick rubber bearings, and the difference of mechanical characteristics was only the dependency of the vertical stiffness on the horizontal displacement. Second, we carried out shaking table test for scaled model of base isolated structure. The results showed that horizontal characteristics of thick rubber bearing was almost the same as the thin one, and the vertical stiffness was able to be determined according to the resonance period of internal equipments. After the test, we carried out the numerical analysis on the shaking table test. Numerical results showed that the response of the model for earthquake input motion and its response spectra were in good agreement with the experiment, and the resonance peak of the floor response spectra can be reduced when the damping coefficient of the vertical damper increases. (author)

  4. Evaluation of rubber seal products for gamma facilities

    International Nuclear Information System (INIS)

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

  5. EVALUATION OF TIRE RUBBER DISPOSAL IN CONCRETE FOR PAVEMENTS

    Directory of Open Access Journals (Sweden)

    Rosa Cristina Cecche Lintz

    2009-12-01

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

  6. Cancer mortality among male workers in the Polish rubber industry.

    Science.gov (United States)

    Szeszenia-Dabrowska, N; Wilczyńska, U; Kaczmarek, T; Szymczak, W

    1991-01-01

    The rubber industry, acknowledged by the International Agency for Research on Cancer (IARC) to be a cancer risk technology is, because of difficulty in identifying causal factors, the subject of intensive epidemiological studies in many countries. In the presented study, cancer risk in the rubber industry was evaluated on the basis of long-term observation (1945-1985) of a cohort of 6978 male workers employed in a rubber goods factory, predominantly engaged in producing rubber footwear. The reference group was the general male population of Poland. Standardized mortality ratios (SMRs), calculated by means of the person-years method, were used in the evaluation of death risk. The observation of a whole cohort indicated an excess of cancer, in general (approx 12%), lung cancer (approx 40%) and gallbladder cancer (approx fourfold). In the subcohorts, distinguished according to peculiarities of individual production sections, cancer risk of the large intestine and larynx was significantly increased. The highest cancer risk was found in compounding, mixing, milling and vulcanizing sections. Hence, beta-naphthylamine, benzidine and solvents (benzene) were used in technological processes in the past, bladder cancer and leukemia were considered as most specific for the rubber industry. In the cohort observed, the risk of death from bladder cancer was significantly increased only in those who had been employed during the years 1945-1953, namely during the period when beta-naphthylamine was in use. No excess of deaths from leukemia was observed. PMID:1799640

  7. EB-promoted recycling of waste tire rubber with polyolefins

    International Nuclear Information System (INIS)

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

  8. Nanolipoprotein particles comprising a natural rubber biosynthetic enzyme complex and related products, methods and systems

    Energy Technology Data Exchange (ETDEWEB)

    Hoeprich, Paul D.; Whalen, Maureen

    2016-04-05

    Provided herein are nanolipoprotein particles that comprise a biosynthetic enzyme more particularly an enzyme capable of catalyzing rubber or other rubbers polymerization, and related assemblies, devices, methods and systems.

  9. Influence of Ultrasonic Vibrations on the Static Friction Characteristics of a Rubber/Aluminum Couple

    Institute of Scientific and Technical Information of China (English)

    程廷海; 高焓; 包钢

    2011-01-01

    A novel ultrasonic vibration approach is introduced into a chloroprene rubber/aluminum friction couple for improving the static friction properties betwesn rubber and metal.Compared to the test results without vibrations,the static friction force of a chloroprene rubber/aluminum couple decreases observably,leading to the ultimate displacement of rubber.The values of the static friction force and ultimate displacement can be ultimately reduced to 23.1% and 50% of those without ultrasonic vibrations,respectively.%A novel ultrasonic vibration approach is introduced into a chioroprene rubber/aluminum friction couple for improving the static friction properties between rubber and metal. Compared to the test results without vibrations, the static friction force of a chioroprene rubber/aluminum couple decreases observably, leading to the ultimate displacement of rubber. The values of the static friction force and ultimate displacement can be ultimately reduced to 23.1% and 50% of those without ultrasonic vibrations, respectively.

  10. Methylene blue related sterile endophthalmitis.

    Science.gov (United States)

    Lim, A K E; Ulagantheran V, V; Siow, Y C; Lim, K S

    2008-08-01

    To report a case of methylene blue related endophthalmitis. Observational case report. Review of clinical record, photographs. A 60 year old man developed endophthalmitis after methylene blue was accidentally used to stain the anterior capsule during phacoemulsification of cataract. His left visual acuity deteriorated from 6/12 to 6/36 two weeks after the operation. Despite intensive treatment with topical and intravitreal antibiotics, his condition deteriorated. A vitrectomy and silicone oil injection eventually managed to control the progression of the disease and salvage the eye. However the visual outcome remained poor due to corneal decompensation and retinal ischemia. Both vitreous tap and vitreous biopsy were negative for any organism. Methylene blue is extremely toxic to ocular structures and should not be used intraocularly. PMID:19248701

  11. Why Do Proteins Glow Blue?

    CERN Document Server

    Sarkar, Sohini; Hazra, Partha; Mandal, Pankaj

    2014-01-01

    Recent literatures reported blue-green emission from amyloid fibril as exclusive signature of fibril formation. This unusual visible luminescence is regularly used to monitor fibril growth. Blue-green emission has also been observed in crystalline protein and in solution. However, the origin of this emission is not known exactly. Our spectroscopic study of serum proteins reveals that the blue-green emission is a property of protein monomer. Evidences suggest that semiconductor-like band structure of proteins with the optical band-gap in the visible region is possibly the origin of this phenomenon. We show here that the band structure of proteins is primarily the result of electron delocalization through the peptide chain, rather than through the hydrogen bond network in secondary structure.

  12. The blue-collar brain.

    Science.gov (United States)

    Van Orden, Guy; Hollis, Geoff; Wallot, Sebastian

    2012-01-01

    Much effort has gone into elucidating control of the body by the brain, less so the role of the body in controlling the brain. This essay develops the idea that the brain does a great deal of work in the service of behavior that is controlled by the body, a blue-collar role compared to the white-collar control exercised by the body. The argument that supports a blue-collar role for the brain is also consistent with recent discoveries clarifying the white-collar role of synergies across the body's tensegrity structure, and the evidence of critical phenomena in brain and behavior. PMID:22719730

  13. Rubber Composites Based on Polar Elastomers with Incorporated Modified and Unmodified Magnetic Filler

    OpenAIRE

    Kruželák, Ján; Sýkora, Richard; Dosoudil, Rastislav; Hudec, Ivan

    2016-01-01

    Rubber magnetic composites were prepared by incorporation of unmodified and surface modified strontium ferrite into rubber matrices based on NBR and NBR/PVC. Strontium ferrite was dosed to the rubber matrices in concentration scale ranging from 0 to 100 phr. The main goal was to investigate the influence of the type of ferrite on the curing process, physical-mechanical and magnetic properties of composites. The mutual interactions between the filler and rubber matrices were investigated by de...

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

    OpenAIRE

    Haiping Zhou; Sri Holikatti; Peter Vacura

    2014-01-01

    The California Department of Transportation (Caltrans) has been using scrap tire rubber in asphalt pavements since the 1970s in chip seals and the 1980s in rubberized hot mix asphalt(RHMA). Both the wet (field blend) and dry processes were used in early trials. Caltrans has also used rubber modified binders containing both crumb rubber modifier and polymer modifier that could be manufactured at a refinery facility, a terminal blend wet process. Since the beginning of this century, Caltrans in...

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

    International Nuclear Information System (INIS)

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

  16. Situation of wastewater treatment of natural rubber latex processing in the Southeastern region, Vietnam

    OpenAIRE

    Nguyen, Nhu Hien; Luong, Thanh Thao

    2012-01-01

    Rubber tree is one of the main plants which play an important role in the economy of Southeastern region, Vietnam. Approximately 90% of Vietnamese natural rubber latex is exported as raw products. The preliminary process of natural rubber latex discharges a large amount of wastewater to the environment. In Vietnam, there are many available technologies set up and operated for treatment wastewater of rubber latex processing. However, the effluent quality is still poor and the concentration of ...

  17. Effect of electron beam irradiation on the properties of crosslinked rubbers

    International Nuclear Information System (INIS)

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

  18. The influence of temperature and reaction time in the degradation of natural rubber latex

    International Nuclear Information System (INIS)

    Liquid natural rubber (LNR /LENR) should be considered as a new material instead of a new type of rubber though they have the same configuration as the rubber used. In this work, thermal degradation of natural rubber latex was carried out to obtain LNR/LENR by varying the reaction time at different temperatures. The degraded polymers were characterized structurally using FTIR and NMR spectroscopies and the average molecular weights were determined by membrane-osmometry and viscometry. (author)

  19. A Review on Using Crumb Rubber in Reinforcement of Asphalt Pavement

    OpenAIRE

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

    2014-01-01

    An immense problem affecting environmental pollution is the increase of waste tyre vehicles. In an attempt to decrease the magnitude of this issue, crumb rubber modifier (CRM) obtained from waste tyre rubber has gained interest in asphalt reinforcement. The use of crumb rubber in the reinforcement of asphalt is considered as a smart solution for sustainable development by reusing waste materials, and it is believed that crumb rubber modifier (CRM) could be an alternative polymer material in i...

  20. Optimization of asphalt rubber hot mixes based on performance laboratory tests

    OpenAIRE

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

    2003-01-01

    Asphalt binders modified with crumb rubber recycled from ground tires have been successfully used in asphalt mixtures improving the mechanical and functional behaviour of the pavements. This paper shows the influence of several factors that affect the behaviour of asphalt-rubber (AR) and of hot mixes made with this material. Modified binders were prepared using a straight binder with 35/50 penetration and rubber obtained by the environmental process. Samples of asphalt-rubber w...

  1. Recycled tyre rubber modified bitumens for road asphalt mixtures: a literature review

    OpenAIRE

    Lo Presti, Davide

    2013-01-01

    Nowadays, only a small percentage of waste tyres are being land-filled. The Recycled Tyre Rubber is being used in new tyres, in tyre-derived fuel, in civil engineering applications and products, in moulded rubber products, in agricultural uses, recreational and sports applications and in rubber modified asphalt applications. The benefits of using rubber modified asphalts are being more widely experienced and recognized, and the incorporation of tyres into asphalt is likely to increase. The te...

  2. Strength and deformability of waste tyre rubber-filled reinforced concrete columns

    OpenAIRE

    Son, K.S.; Hajirasouliha, I.; PILAKOUTAS, K

    2011-01-01

    This study aims to investigate the efficiency of waste tyre rubber-filled concrete to improve the deformability and energy absorption capacity of RC columns by considering different concrete compressive strength, size of waste tyre rubber particles and rubber content. Twelve column specimens were tested using concrete of compressive strength 24 and 28 MPa mixed with 0.6 and 1 mm tyre rubber particles. For each concrete batch, 27 control specimens were prepared to examine the concrete properti...

  3. Effect of electron beam irradiation on the properties of crosslinked rubbers

    Science.gov (United States)

    Banik, Indranil; Bhowmick, Anil K.

    2000-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Mazda, T. [Kyushu Univ., Fukuoka (Japan); Ootori, Y.; Yabana, S.; Hirata, K.; Ishida, K. [Central Research Inst. of Electric Power Industry, Chiba (Japan)

    1995-12-01

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

  5. A study on nonlinear finite element analysis of laminated rubber bearings. Pt.1. Development of evaluation method for mechanical properties of laminated rubber bearings for horizontal base isolation system considering volumetric deformation of rubber material

    International Nuclear Information System (INIS)

    The purpose of this research is to develop the evaluation method for mechanical properties of laminated rubber bearings by nonlinear finite element method (FEM) considering the volumetric deformation of natural rubber material. Relationship between pressure and volumetric strain of the natural rubber is obtained from the volumetric tests and is introduced into user-subroutine of the FEM code (ABAQUS). Finite element analyses of natural rubber bearings (NRB) and the natural rubber bearing with lead plug (LRB) are carried out. The results may be summarized as follows; 1) Horizontal, vertical stiffness and effect of shear deformation on vertical stiffness of natural rubber bearings that have various shape are simulated with enough accuracy. 2) Horizontal and vertical stiffness of LRB are also simulated well. (author)

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

    Science.gov (United States)

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

    2016-07-13

    Introducing ionic associations is one of the most effective approaches to realize a self-healing behavior for rubbers. However, most of commercial rubbers are nonpolar rubbers without now available functional groups to be converted into ionic groups. In this paper, our strategy was based on a controlled peroxide-induced vulcanization to generate massive ionic cross-links via polymerization of zinc dimethacrylate (ZDMA) in natural rubber (NR) and exploited it as a potential self-healable material. We controlled vulcanization process to retard the formation of covalent cross-link network, and successfully generated a reversible supramolecular network mainly constructed by ionic cross-links. Without the restriction of covalent cross-linkings, the NR chains in ionic supramolecular network had good flexibility and mobility. The nature that the ionic cross-links was easily reconstructed and rearranged facilitating the self-healing behavior, thereby enabling a fully cut sample to rejoin and retain to its original properties after a suitable self-healing process at ambient temperature. This study thus demonstrates a feasible approach to impart an ionic association induced self-healing function to commercial rubbers without ionic functional groups. PMID:27337545

  7. Effect of expanded graphite and modified graphite flakes on the physical and thermo-mechanical properties of styrene butadiene rubber/polybutadiene rubber (SBR/BR) blends

    International Nuclear Information System (INIS)

    Highlights: • Modified graphite flakes/carbon black filled SBR and SBR/BR blend were synthesized. • Mechanical and thermomechanical properties of the composites were widely studied. • Composites with improved antiskid property and low rolling resistance were obtained. - Abstract: The aim of the present research work is to develop expanded graphite (EG) and isocyanate modified graphite nanoplatelets (i-MG) filled SBR/BR blends, which can substitute natural rubber (NR) in some application areas. The present study investigated the effect of i-MG on the physical, mechanical and thermo-mechanical properties of polybutadiene rubber (BR), styrene butadiene rubber (SBR) and SBR/BR blends in the presence of carbon black (CB). Graphite sheets were modified to enhance its dispersion in the rubber matrices, which resulting in an improvement in the overall physical and mechanical properties of the rubber vulcanizates. Compounds based on 50:50 of BR and SBR with ∼3 wt% nanofillers with CB were fabricated by melt mixing. The morphology of the filled rubber blends was investigated by wide angle X-ray diffraction (WAXD) and high resolution transmission electron microscopic (HR-TEM) analyses. The intercalated and delaminated structures of the nanofiller loaded rubber blends were observed. Scanning electron microscopic (SEM) analysis of the cryo-fractured surfaces of the rubber compounds showed more rough and tortuous pathway of the fractured surfaces compared to the fractured surfaces of the only CB loaded rubber composites. Filled rubber compounds exhibit increase in the ΔS (torque difference) value, reduced scorch and cure time compared to their respective controls. Dynamic mechanical thermal analysis (DMTA) of the filled rubber compounds shows an increase in the storage modulus compared to the controls. Isocyanate modified graphite nanoplatelets (i-MG) containing rubber compounds in the presence of CB showed an increase in the mechanical, dynamic mechanical, hardness

  8. Rheological behavior of raw natural rubber coagulated by microorganisms

    Directory of Open Access Journals (Sweden)

    Zhifen Wang

    2014-01-01

    Full Text Available Tests of the strain sweep, frequency sweep and stress relaxation for raw natural rubber coagulated by microorganisms (NR-m and raw natural rubber coagulated by acid (NR-a were carried out with the use of a rubber process analyzer (RPA. The results showed that the storage torque, complex viscosity of NR-m were higher than those of NR-a while the loss factor was lower. The effect of temperature on viscosity of raw NR was studied following the Arrhenious-Frenkel-Eyring model. The viscous flow behavior of NR-m was poorer than those of NR-a. Furthermore, stress relaxation measurements of raw NR showed a longer period of relaxation for NR-m.

  9. Testing of rubber O-rings for R-5 reactor

    International Nuclear Information System (INIS)

    This paper summarises the results of various experiments and tests conducted for the selection of suitable O-rings to be used in R-5 reactor. O-rings of various elastomeric compositions obtained from different manufacturers were tested for heat aging, fluid aging, radiation stability and specific gravity. They were irradiated to various dose levels at Apsara Reactor. The changes in axial thickness and hardness, after each test, were measured and results were correlated. The tests reveal that O-rings made of ethylene-propylene rubber are the best suited for the use in R-5 reactor. The O-rings made of nitrile rubber are also good. Neoprene rubber O-rings were found unsuitable mainly because of their low radiation resistance. (author)

  10. Dynamic Viscoelasticity of Polyester/Rubber Composites under Cyclic Loading

    Institute of Scientific and Technical Information of China (English)

    Yuyan LIU; Zhenhui TIAN; Zhimin XIE; Xingwen DU

    2005-01-01

    This paper focuses on the influence of dynamic viscoelasticity and surface temperature on the fatigue mechanism and fatigue lifetime of polyester/rubber composites. Rubber composites show significant viscoelasticity during fatigue process. The variations of dynamic elastic modulus, mechanical loss angle, loss energy per cycle exhibit different trend in fatigue initial stage and final stage. Due to high viscoelasticity high heat generation occurs under cyclic loading, which leads to a high surface temperature. It is found that the variation of specimen surface temperaturedepends strongly on cycling frequency and stress amplitude. SEM (scanning electron microscopy) observation and static residual stiffness studies reveal that the surface temperature affects fracture morphology and fatigue lifetime of rubber composites strongly because of heat aging.

  11. Draft genome sequence of the rubber tree Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Rahman Ahmad Yamin Abdul

    2013-02-01

    Full Text Available Abstract Background Hevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR. NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876. Results Here, we report the draft genome sequence of H. brasiliensis. The assembly spans ~1.1 Gb of the estimated 2.15 Gb haploid genome. Overall, ~78% of the genome was identified as repetitive DNA. Gene prediction shows 68,955 gene models, of which 12.7% are unique to Hevea. Most of the key genes associated with rubber biosynthesis, rubberwood formation, disease resistance, and allergenicity have been identified. Conclusions The knowledge gained from this genome sequence will aid in the future development of high-yielding clones to keep up with the ever increasing need for natural rubber.

  12. Evaluation of rubber composites as shielding materials against ionizing radiation

    International Nuclear Information System (INIS)

    Styrene-butadiene rubber/lead oxide composites were prepared as γ-radiation shields.The composites were prepared with different concentration of red lead oxide (Pb3O4) .The assessment of the linear attenuation coefficient of the SBR/lead oxide composites for γ -rays from 137 Cs137 γ-radiation point source was studied . The factors affecting the mechanical properties and shielding capacity of the composites were also studied. These factors include the lead oxide concentration, the type of monomers added and the irradiation dose. The styrene-butadiene rubber/lead oxide composites can attain up to about 43% of the shielding capacity of pure lead. The incorporation of high concentrations of lead oxide and the effect of accumulative irradiation doses up to 3000 kGy on the physico-mechanical properties of the composites were studied . These led to hardening of the SBR rubber/lead oxide composites.

  13. Polysiloxane Functionalized Carbon Dots and Their Cross-Linked Flexible Silicone Rubbers for Color Conversion and Encapsulation of White LEDs.

    Science.gov (United States)

    Wang, Yunfeng; Yin, Zhengmao; Xie, Zheng; Zhao, Xinxin; Zhou, Chuanjian; Zhou, Shuyun; Chen, Ping

    2016-04-20

    In this work, aminopropylmethylpolysiloxane (AMS) functionalized luminescent carbon dots (AMS-CDs) were prepared via a one-step solvothermal method. AMS-CDs could be self- or co-cross-linking with AMS to form 3D flexible transparent silicone rubbers (SRs) where CDs acted as cross-linking points, so the loading fraction of AMS-CDs could be adjusted from 10 to 100 wt %, thus modulating fluorescence properties and flexibility of silicone rubbers. Because of the self-curing property and high thermal stability, AMS-CDs were also studied in white LEDs (WLEDs), serving as a color conversion and encapsulation layer of GaN based blue LEDs simultaneously that would avoid the traditional problem of poor compatibility between emitting and packaging materials. And the color coordinate of AMS-CDs based WLEDs (0.33, 0.28) was very close to the pure white light. In addition, the obtained CDs cross-linked SRs had good transparency (T > 80%) at 510-1400 nm and high refractive indexes (1.33-1.54) that could meet the need of commercial packaging materials and optical application. AMS-CDs were also promising to be used in the UV LEDs based WLEDs according to their wide wavelength emission and flexible optoelectronic device. PMID:27035213

  14. Alternative vulcanization process of natural rubber latex induced by ionizing radiation

    International Nuclear Information System (INIS)

    The natural rubber latex was vulcanized by two different process: a) thermal process in the presence of sulfur; b) alternative process using radiation (gamma rays and electrons beam). The comparative study of rubber goods quality (surgical gloves and balloons) was carried out by physical and chemical properties of pre vulcanized latex and physical and mechanics properties of rubber goods for two process. (author)

  15. Breakthroughs of Low-temperature Direct Rubber Mixing in Low-carbon Technology

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Rubber mixing is the most energy-consuming procedure in tire production, covering about 40% energy of the whole tire producing workflow. The process of low temperature direct rubber mixing, developed by Triangle Group Co., Ltd., MESNAC Co., Ltd., Yiyang Rubber and Plastics Co., Ltd., TTA (Qingdao) Tire Technology Co., Ltd., Guangzhou SCUT Bestry Technology Co., Ltd., etc.

  16. Turbidimetric behavior of Butadiene Rubber (BR) solutions in toluene and dichloromethane after heating at open air

    International Nuclear Information System (INIS)

    This paper deals with the turbidimetric behavior of Butadiene Rubber BR solutions, a synthetic rubber, in two solvents (toluene and dichloromethane), after heating at open air till 180 Deg Celsius for optimal polymer cracking conditions. Concentration, solvent and temperature effects have been studied using methanol as precipitant. Butadiene rubber exhibits a high sensitivity to autoxidation with high tendency to reticulation.

  17. Occupational vitiligo due to unsuspected presence of phenolic antioxidant byproducts in commercial bulk rubber

    Energy Technology Data Exchange (ETDEWEB)

    O' Malley, M.A.; Mathias, C.G.; Priddy, M.; Molina, D.; Grote, A.A.; Halperin, W.E.

    1988-06-01

    We investigated the occurrence of cutaneous depigmentation (vitiligo) among employees of a company that manufactured hydraulic pumps. The interiors of these pumps were injection-molded with rubber. We identified a small but significant cluster of vitiligo cases among a group of employees who frequently handled the rubber used in this injection molding process. Although none of the additives specified in the rubber formulations was a phenolic or catecholic derivative, known to be potential causes of chemically induced vitiligo, gas chromatographic analysis identified a para-substituted phenol (2,4-di-tert-butylphenol, DTBP) in solid samples of the most frequently used rubber. Surface wipe analysis confirmed that workers could be exposed to DTBP from simple handling of the rubber. We subsequently established that the solid bulk rubber used as the base in these stock rubber formulations contained both DTBP and smaller quantities of p-tert-butylphenol. Both had formed as unsuspected byproducts during chemical synthesis of two antioxidants added to the solid bulk rubber by a major rubber supplier. We conclude that the unsuspected presence of potential chemical depigmenting agents in solid bulk rubber, from which industrial rubber products are formulated, may contribute to the occurrence of occupational vitiligo, and that a simple review of ingredients in rubber formulations is inadequate to detect their presence.

  18. 78 FR 58520 - Extruded Rubber Thread From Malaysia; Notice of Amended Final Results of Antidumping Duty...

    Science.gov (United States)

    2013-09-24

    ... International Trade Administration Extruded Rubber Thread From Malaysia; Notice of Amended Final Results of... review of the antidumping duty order on extruded rubber thread from Malaysia.\\1\\ The period of review (POR) is October 1, 1995, through September 30, 1996. \\1\\ See Extruded Rubber Thread From...

  19. 40 CFR 428.80 - Applicability; description of the wet digestion reclaimed rubber subcategory.

    Science.gov (United States)

    2010-07-01

    ... digestion reclaimed rubber subcategory. 428.80 Section 428.80 Protection of Environment ENVIRONMENTAL... Wet Digestion Reclaimed Rubber Subcategory § 428.80 Applicability; description of the wet digestion... discharges resulting from the production of reclaimed rubber by use of the wet digestion process....

  20. Improvement of hydrophilic property of rubber dipping former surface with Ni/B/TiO{sub 2} nano-composite film

    Energy Technology Data Exchange (ETDEWEB)

    Sikong, L., E-mail: lek.s@psu.ac.th [Department of Mining and Materials Engineering, Faculty of Engineering, Prince of Songkla University, Songkhla (Thailand); Masae, M.; Kooptarnond, K. [Department of Mining and Materials Engineering, Faculty of Engineering, Prince of Songkla University, Songkhla (Thailand); Taweepreda, W. [Department of Materials Science and Technology, Faculty of Science, Prince of Songkla University, Songkhla (Thailand); Saito, F. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai (Japan)

    2012-03-01

    The objective of this study is to explore a method to improve hydrophilicity of the surface of formers that could be more easily dipped to produce high quality dipped rubber products. Photocatalytic TiO{sub 2} composite films were prepared by sol-gel method. Glass formers were coated with the Ni/B/TiO{sub 2} nano-composite film by dipping method and annealed at 400 Degree-Sign C for 1 h. Phase formation of TiO{sub 2} was characterized by XRD. Morphology of the TiO{sub 2} films was observed by using atomic force microscopy (AFM). Optical absorption of the films and degradation concentration of methylene blue had been measured employing UV-vis spectrophotometer. The hydrophilicity of the thin films was determined in terms of the contact angles of water and NR rubber latex droplets on the coated TiO{sub 2} composite films with and without UV irradiation. It was found from the experimental study that the Ni/B/TiO{sub 2} nano-composite film can improve wet-ability of the coated former surfaces, leading to enhancement of tensile strengths of the vulcanized natural rubber (NR) latex films.

  1. Fracture Behavior of Silica- and Rubber-Nanoparticle-Toughed Epoxies

    Science.gov (United States)

    Labak, Amelia K.

    Particle-toughened crosslinked epoxies are popular materials for a variety of applications, including the microelectronics industry. For this application, the properties of these materials, such as a high fracture toughness and a low coefficient of thermal expansion, are highly appealing. In order to achieve these properties, inorganic particles are often added into the matrix. For this study, both inorganic and organic particles-toughened epoxies are investigated in the hopes of finding an optimized system. In particular, in this study, micron-sized silica and nano-sized rubbery block copolymers are added to an amine-cured epoxy matrix. A series of rubber-only and silica-only systems are investigated for their contribution to the fracture toughness. Then, a series of hybrid systems are investigated. The hypothesis is that the rubber will contribute toughness through rubber particle cavitation and matrix void growth and the silica will contribute toughness through crack pinning and bridging and particle debonding. In the hybrid systems, these mechanisms will take place at a different scale. Therefore, the nanoscale mechanisms of the rubber will be able to function at the same time as the micron sized mechanisms of the silica and the resultant toughness will be synergistically higher. The results from this study show an interesting contribution from the rubber particles both in the rubber-only systems and the hybrid system. Ultimately, there was a marked increase in the fracture toughness of the hybrid systems, although not synergistic. This increase indicates that it would be possible to create an optimized hybrid system from the combined addition of these particles.

  2. Natural rubber latex: past, present and future in Latin America

    International Nuclear Information System (INIS)

    The origin of the Hevea braziliensis tree was the Amazonian region in South America, particularly the Brazilian jungle. The rubber expansion at the end of 9th century brought prosperity and determined the borders of Amazonian countries. In spite of that, the Brazilian government has failed in establishing a successful policy for improving the NR production in the jungle. However, rubber plantations were successfully introduced recently near marginal areas of the humid forest in the Amazon due to the absence of the fungus Microcyclos ulei. Both, extraction of wild rubber and plantation have a key role in the maintenance of the forest health. The market for dipping products is small but is growing very fast and is expected to follow this pattern as the sanitary conditions are improved by the health authority. The history of the Brazilian NR products industry is contemporary and is based on the policy of market protection and on the lack of investments due to extremely high interest rates. As a result, the industry was not competitive. It was concluded that, in order to cope with the future challenge, the industry is required to invest in very modern technologies to produce first class goods with international acceptance. Latin America would follow the world trend for nitrosamine and protein free products. The radiation vulcanization of natural rubber latex could prove itself as a profitable solution and not only a quality solution. It was also concluded that both wild rubber and rubber plantations in Brazil have their future coupled with the future of a regional dipping industry. Moreover, the buildup of the dipping industry will be beneficial to the protection of the humid forest and the recovery of degraded areas

  3. Radiation processing of natural rubber and its applications

    International Nuclear Information System (INIS)

    Research in natural rubber (NR) is still offering good and exciting opportunities especially in making NR into superior products and as a source for new chemicals by modification of its structure. As in the case of liquid epoxidised natural rubber acrylic (LENRA), it has been shown that it has the ability to induce the interfacial interaction between NR and polyolefin i.e. High-density polyethylene (HDPE) as demonstrated by Transmission Electron Microscopy (TEM) and small angle neutron scattering (SANS) techniques. For NR/HDPE blend, without deuteration technique, SANS was also to induce some scattering data leading to fruitful information on the interfacial interaction between the blend compositions. (author)

  4. Recent developments in radiation vulcanisation of natural rubber latex

    International Nuclear Information System (INIS)

    Natural rubber latex, an important industrial raw material, is cross linked using energy of gamma radiation. To reduce the energy of radiation, sensitizers like n-butyl acrylate are used. The product so obtained is called radiation vulcanized natural rubber latex (RVNRL). This product is found to have many superior properties in comparison to the conventionally cross linked latexes. Because of the very low levels of cytotoxicity and nitrosamines in RVNRL, it is expected to be the future raw material for producing products like nipples, catheters, balloons and gloves. (author)

  5. Behavior of Rubber Materials under Exposure to High Electric Fields

    DEFF Research Database (Denmark)

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

    2013-01-01

    The effect of high electrical stress on rubber materials is investigated by performing breakdown tests and tracking resistance tests on selected samples. The study is focused on the relationship between the dielectric strength and the thickness of the samples, as well as the influence of the inte......The effect of high electrical stress on rubber materials is investigated by performing breakdown tests and tracking resistance tests on selected samples. The study is focused on the relationship between the dielectric strength and the thickness of the samples, as well as the influence...

  6. Permeability of irradiated silicon rubber membranes to gases

    International Nuclear Information System (INIS)

    This paper investigates the effect of irradiation on the permeability of silicone rubber membranes to gases. Commercial medical-grade silicone rubber membranes were used, and the irradiation was by 60Co in air or under vacuum. A permeation apparatus equipped with a Pirani gauge was developed. The permeability, diffusion, and solubility coefficients for helium, krypton, nitorgen, oxygen, carbon dioxide, and propane were measured over the temperature range of 0 to 700C. It is concluded that the irradiation effects are negligibly small compared with these in polyethylene

  7. Nobel Prize for blue LEDs

    Science.gov (United States)

    Kraftmakher, Yaakov

    2015-05-01

    A brief review of lighting technologies is presented. Unavoidable restrictions for incandescent light bulbs caused by the Planck distribution and properties of the human eye are illustrated. The efficiency and luminous efficacy of thermal radiation are calculated for various temperatures; the results clearly show the limitations for thermal radiators. The only way to overcome these limitations is using non-thermal radiators, such as fluorescent lamps and light-emitting diodes (LEDs). Unique advantages of LEDs undoubtedly made a revolution in this field. A crucial element of this progress is the blue LEDs (Nobel Prize 2014). Some experiments with a blue and a green LED are described: (i) the luminescence triggered in a green-yellow phosphor inside a white LED by the blue LED; (ii) radiant spectra and ‘efficiency droop’ in the LEDs; (iii) modulation of the blue LED up to 4 MHz; and (iv) the h/e ratio from the turn-on voltage of the green LED. The experiments are suitable for undergraduate laboratories and usable as classroom demonstrations.

  8. Maillard Reaction in Natural Rubber Latex: Characterization and Physical Properties of Solid Natural Rubber

    Directory of Open Access Journals (Sweden)

    S. Montha

    2016-01-01

    Full Text Available Maillard reaction in Natural Rubber (NR latex was investigated by treating fresh NR latex with glutaraldehyde (C5H8O2 in amounts of 0, 50, 100, and 200 mmol/kg of latex. Protein cross-linking in fresh NR latex and solid NR was confirmed by using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE and attenuated total reflection infrared (ATR-IR spectroscopy, respectively. It was found that degree of protein cross-linking in NR increased with increasing C5H8O2 concentration. Physical properties of untreated and treated NR substances in terms of gel content, initial Wallace plasticity (P0, plasticity retention index (PRI, Mooney viscosity, and tensile strength were carefully explored. Results clearly showed that the Maillard cross-linking of proteins had remarkable effect on bulk NR properties, that is, solvent resistance, hardness, resistance to oxidation, rheological behavior, and resistance to stretching out.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

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

    DEFF Research Database (Denmark)

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

    1997-01-01

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

  12. Cooking time harmonization attempts for main rubbers in a truck tyre-III. Activation energy evaluation

    International Nuclear Information System (INIS)

    The harmonization of optimum cooking time of rubbers containing in a tyre is became possible. This occurrence is the result of the knowledge about the respective function of each element containing in the rubber. Many kind of rubbers are been studied. The obtained results demonstrate the realization of the harmonization of optimum cooking time in different rubbers at some conditions by modifying either a kind of vulcanization accelerator or a quantity of vulcanization activator. So, accelerator or activator modifies need of energy during cooking. In this paper, we are estimated activation energy for all new rubbers obtained

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

    OpenAIRE

    Guo, Rui

    2009-01-01

    In industrial applications, different rubber types are often blended to fine-tune or optimize the property portfolio required for successful performance of articles. Considering the complexity of a rubber blend compound, wherein numerous additives are involved, vulcanization or cure mismatch often occurs as an outcome of inhomogeneous distribution of the curatives or imbalanced reactivities of the different rubber phases towards the curatives. The solubility study of various curatives in diff...

  14. Genome-wide identification of rubber tree (Hevea brasiliensis Muell. Arg.) aquaporin genes and their response to ethephon stimulation in the laticifer, a rubber-producing tissue

    OpenAIRE

    Zou, Zhi; Gong, Jun; An, Feng; Xie, Guishui; Wang, Jikun; Mo, Yeyong; Yang, Lifu

    2015-01-01

    Background Natural rubber, an important industrial raw material, is specifically synthesized in laticifers located inside the rubber tree (Hevea brasiliensis Muell. Arg.) trunk. Due to the absence of plasmodesmata, the laticifer water balance is mediated by aquaporins (AQPs). However, to date, the characterization of H. brasiliensis AQPs (HbAQPs) is still in its infancy. Results In this study, 51 full-length AQP genes were identified from the rubber tree genome. The phylogenetic analysis assi...

  15. Flavour production of Stilton blue cheese microflora

    OpenAIRE

    Gkatzionis, Konstantinos

    2010-01-01

    In the blue cheese Stilton the starter mould Penicillium roqueforti grows and sporulates during the ripening period and is considered to be responsible for the unique blue cheese aroma. However, the sporulation of the mould, which results in the formation of blue veins, takes place in a fraction of the Stilton matrix which overall is very heterogeneous. Most blue cheeses develop a secondary microflora of yeasts which may affect their aroma. The aim of this study was to investigate the yeast f...

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

    Directory of Open Access Journals (Sweden)

    Haiping Zhou

    2014-02-01

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

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

    OpenAIRE

    D. A. Baeta; J. A. Zattera; M. G. Oliveira; Oliveira, P J

    2009-01-01

    Styrene-butadiene rubber (SBR) has large applications in the shoe industry, especially as expanded sheets used to produce insoles and inner soles. According to TG analysis, the rubber content in SBR residues (SBR-r) was found to be around 26-wt%. Based on that data, a cost-effective technique for the reuse of SBR-r in Nitrile rubber (NBR) was developed. Later, the effect of SBR-r on the cure behavior, mechanical performance, swelling, and crosslink density of reused rubber was investigated, w...

  18. Genetic and biochemical evaluation of natural rubber from Eastern Washington prickly lettuce (Lactuca serriola L.).

    Science.gov (United States)

    Bell, Jared L; Burke, Ian C; Neff, Michael M

    2015-01-21

    Alternative sources of natural rubber are of importance due to economic, biological, and political threats that could diminish supplies of this resource. Prickly lettuce (Lactuca serriola L.) synthesizes long-chain natural rubber and was studied to determine underlying genetic and phenotypic characteristics of rubber biosynthesis. Genotypic and phenotypic analysis of an F2 segregating population using EST-SSR markers led to the discovery of genetic regions linked to natural rubber production. Interval mapping (IM) and multiple QTL mapping (MQM) identified several QTL in the mapping population that had significance based on LOD score thresholds. The discovered QTL and the corresponding local markers are genetic resources for understanding rubber biosynthesis in prickly lettuce and could be used in marker-assisted selection (MAS) breeding. Prickly lettuce is an excellent candidate for elucidating the rubber synthesis mechanism and has potential as a crop plant for rubber production. PMID:25513853

  19. Study on grafting of different types of acrylic monomers onto natural rubber by {gamma}-rays

    Energy Technology Data Exchange (ETDEWEB)

    Dafader, N.C. [Nuclear and Radiation Chemistry Division, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, P.O. Box 3787, Dhaka (Bangladesh)]. E-mail: nrcd@instaere.com; Haque, M.E. [Nuclear and Radiation Chemistry Division, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, P.O. Box 3787, Dhaka (Bangladesh)]. E-mail: nrcd@instaere.com; Akhtar, F. [Nuclear and Radiation Chemistry Division, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, P.O. Box 3787, Dhaka (Bangladesh)]. E-mail: nrcd@instaere.com; Ahmad, M.U. [Department of Chemistry, Jahangirnagar University, Savar, Dhaka (Bangladesh)]. E-mail: mesbah_ahmad@hotmail.com

    2006-01-15

    A comparative study of various acrylic monomers for grafting onto natural rubber was done. The stability of natural rubber latex (NRL) against coagulum with monomer, mechanical properties of grafted rubbers and percent of grafting were investigated. The NRL with monomers, methylacrylate (MA), ethylacrylate (EA) and n-butylacrylate (n-BA), is unstable but it is stable with methyl methacrylate (MMA), n-butyl methacrylate (BMA) and cyclohexyl methacrylate (CHMA). The mechanical properties and degree of grafting attained a maximum at a total radiation dose of 4 kGy. The values of tensile properties of MMA and CHMA grafted rubbers are almost similar, and higher than those of BMA grafted rubbers. On the other hand, the degree of grafting for CHMA is higher than those of MMA and BMA grafted rubbers. The infrared (IR) spectra of monomer grafted natural rubber were also studied.

  20. Effect of tire rubber particles on crack propagation in cement paste

    Directory of Open Access Journals (Sweden)

    Nadia Segre

    2006-09-01

    Full Text Available Tire rubber particles (NaOH-treated and untreated were investigated as possible crack stabilizer and toughness enhancer when added to cement paste through in situ crack propagation measurements using two different types of cement, type I/II and an Interground polypropylene Fiber Cement (IFC. Crack deflection and crack bridging were observed in specimens with untreated rubber in cement type I/II. Crack tip mechanisms associated with crack pinning and acrack arrest were present in type I/II cement and IFC with treated rubber particles. Crack tip mechanisms in IFC with treated rubber lead to the increase in CMOD at the ultimate load level. Crack wake mechanisms in IFC with untreated or treated rubber lead to strain hardening and strain softening behavior. Crack wake bridging mechanisms were replaced by multiple cracking mechanisms in the IFC specimens with treated rubber. The IFC specimens with untreated rubber inclusions provided the best results with respect to toughness enhancement.

  1. Formulation of tearing energy for fatigue life evaluation of rubber material

    International Nuclear Information System (INIS)

    Fatigue life of metal material can be predicted by the use of fracture theory and experimental database. Although prediction of fatigue life of rubber material uses the same way as metal, there are many reasons to make it almost impossible. One of the reasons is that there is not currently used fracture criteria for rubber material because of non-standardization, various way of composition process of rubber and so on. Tearing energy is one of the fracture criteria which can be applied to a rubber. Even if tearing energy relaxes the restriction of rubber composition, it is also not currently used because of complication to apply in. Research material about failure process of rubber and tearing energy was reviewed to define the process of fatigue failure and the applicability of tearing energy in estimation of fatigue life for rubber. Also, finite element formulation of tearing energy which can be used in FE analysis was developed

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-21

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

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

    Directory of Open Access Journals (Sweden)

    Yue Lian-yong

    2016-01-01

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

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

    International Nuclear Information System (INIS)

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

  5. Plasma melting of miscellaneous solid waste containing rubber

    International Nuclear Information System (INIS)

    Miscellaneous solid waste contains burnable and/or non-burnable materials besides metallic waste. When non-metallic waste is treated by transferred arc plasma, plasma stability may be decreased by the low electrical conductivity of the materials. This paper describes the result of an experiment in which rubber as a typical burnable waste was fed into the crucible of an operating experimental plasma furnace. The power of the plasma was 20 to 50 kW. The base materials of the simulated waste were 10 kg of iron and 3 kg of fly-ash. Up to 10 g of rubber was fed after the base materials had melted. The voltage of the arc plasma increased just after the feed, and the increase was almost proportional to the weight of the fed rubber. The intrusion of thermally decomposed products of the rubber into the plasma dominated the voltage increase. The voltage increase was investigated for several operating conditions of the furnace. The increase of air injection into the furnace and that of arc current controlled the voltage increase during feeding, but the increase of plasma working gas aggravated it. (author)

  6. Tissue-Culture Method of Cloning Rubber Plants

    Science.gov (United States)

    Ball, E. A.

    1983-01-01

    Guayule plant, a high-yield rubber plant cloned by tissue-culture method to produce multiple new plants that mature quickly. By adjusting culture medium, excised shoot tip produces up to 50 identical guayule plants. Varying concentration of cytokinin, single excised tip produces either 1 or several (up to 50) new plants.

  7. Development and Capacity Forecast of China Rubber Raw Materials

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The "1 lth Five-Year Plan" period is the most glorious period in the history of China raw materials such as NR and SR. During the "12th Five-Year Plan" period, the rubber raw materials will enter an important period of great development in technology, product and output.

  8. Rubber Tire Dozer Operator. Open Pit Mining Job Training Series.

    Science.gov (United States)

    British Columbia Dept. of Education, Victoria.

    This training outline for rubber tire dozer operators, one in a series of eight outlines, is designed primarily for company training foremen or supervisors and for trainers to use as an industry-wide guideline for heavy equipment operator training in open pit mining in British Columbia. Intended as a guide for preparation of lesson plans both for…

  9. Radiation Copolymerization of Styrene Monomer Onto Natural Rubber Film

    International Nuclear Information System (INIS)

    Studies on the effect of radiation copolymerization of styrene monomer onto natural rubber film on physical and chemical properties of natural rubber-polystyrene copolymer (NPC) have been done. Natural rubber film firstly immersed in styrene monomer in certain time, then it was wrapped with Mylar film, and then it was irradiated with gamma rays in various doses from 10,25, 50 up to 100 kGy. The styrene monomer content was also varying from 25, 50 and 100 phr (part per hundred part of rubber). Using tensile tester and hardness tester carried out physical characterization of NPC such as modulus-30G, modulus-600, elongation at break, permanent set and hardness. While chemical characterization was carried out by extraction method. The solvent used was acetone and tetrahydrofuran. The experimental results showed that by increasing the styrene monomer at the same irradiation dose, the molecule crosslinked fraction of NPC decreased, while the molecule grafted fraction was increased. But at the saine styrene monomer content, increasing irradiation dose was increasing the molecule crosslinked fraction and decreasing the molecule grafted fraction of NPC. The increasing of molecule crosslinked fraction was effected on the increasing of tensile strength, modulus, hardness, and decreasing of elongation at break of NPC. The tensile strength, modulus, aJId baldness ofNPC were achieved 195 kg/cm2, 108 kg/cm2 and 63 shore respectively at monomer content I00 phr and irradiation dose was 100 kGy

  10. Modification of Asphalt by the Use of Crumb Rubber

    Directory of Open Access Journals (Sweden)

    Shah Room

    2014-01-01

    Full Text Available Health aspects enforced to ponder a study on asphalt which incorporate rubber crumbs to increase strength and flexibility of asphalt. Disposal of waste tires is a menace and it’s a serious problem globally because it is not easily biodegradable as these tires consume large spaces, open burning cause serious problems. By the use of rubber tires, this scrap is utilized efficiently and reduces the cost of asphalt to produce economical system. The asphalt is absorbed by the rubber particles which swells at high temperature allowing greater concentration of liquid asphalt. The partial replacement of crumb rubber in asphalt is 5%, 10%, 15%, and 20% (D05, D10, D15, and D20. The analysis of incorporated asphalt was done in hot mix asphalt. The generated results showed that the value for resilient modulus and creep stiffness is more as compared to the conventional asphalt and in the accumulated strain the values are much lesser which is positive approach.

  11. Feasibility study of a soil-based rubberized CLSM.

    Science.gov (United States)

    Wu, Jason Y; Tsai, Mufan

    2009-02-01

    The development of beneficial uses of recycled scrap tires is always in great demand around the world. The disposal of on-site surplus excavated soil and the production of standard engineering aggregates have also been facing increasing environmental and ecological challenges in congested islands, such as Taiwan. This paper presents an experimental study using recycled crumb rubber and native silty sand to produce a lightweight, soil-based, rubberized controlled low strength material (CLSM) for a bridge approach repair. To assess the technical feasibility of this material, the effects of weight ratios of cement-to-water (C/W) and water-to-solid (W/S), and of rubber content on the engineering properties for different mixtures were investigated. The presented test results include flowability, unit weight, strength, settlement potential, and bearing capacity. Based on the findings, we conclude that a soil-based rubberized CLSM with 40% sand by weight and an optimal design ratio of 0.7 for C/W and 0.35 for W/S can be used for the proposed bridge approach repair. Such a mixture has demonstrated acceptable flowability, strength, and bearing capacity. Its lower unit weight, negligible compressibility, and hydrocollapse potential also help ensure that detrimental settlement is unlikely to occur. The results illustrate a novel scheme of CLSM production, and suggest a beneficial alternative for the reduction of scrap tires as well as conservation of resources and environment. PMID:18678479

  12. Rubber-coated bellows improves vibration damping in vacuum lines

    Science.gov (United States)

    Hegland, D. E.; Smith, R. J.

    1966-01-01

    Compact-vibration damping systems, consisting of rubber-coated metal bellows with a sliding O-ring connector, are used in vacuum lines. The device presents a metallic surface to the vacuum system and combines flexibility with the necessary stiffness. It protects against physical damage, reduces fatigue failure, and provides easy mating of nonparallel lines.

  13. Effect of gamma irradiation on sulfur-cured chlorobutyl rubber

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

    Chlorobutyl rubber (CIIR) is similarly manufactured to butyl rubber (IIR). The insertion of chlorine atom in isoprene group represents an improvement in its properties, such as: high vulcanizing speed, low permanent stress and compatibility with other types of rubber. The presence of reactive chlorine in butyl chlorate allows a variety of vulcanizing techniques, being the cure via sulfur, the most conventional. In these compounds carbon-halogen bonds are weaker than carbon-carbon and carbon-hydrogen bonds, and the main effect of radiation is to break the carbon-halogen bond to give an organic free radical. Irradiations of certain alkyl chlorides can bring about isomerism in which the location of the halogen atom is changed, the carbon skeleton of molecule remaining unaltered. Irradiation of n-butyl chlorides gives high yields of tertiary carbon. The major effect of high energy photon, such as gamma rays, in organic polymers is the generation of free radicals, along changes in mechanical properties. This work aims to the study of irradiation effect on mechanical properties of a sulfur cured chlorobutyl rubber compound, gamma irradiated within 25, 50, 100, 150 e 200 kGy doses range. The techniques used in their characterization were: strength - stress analysis and elasticity modulus. Results obtained were investigated, demonstrated and discussed. (author)

  14. 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...

  15. Pyrolysis of rubber gloves in integral pyrolysis test plant

    International Nuclear Information System (INIS)

    Previously, pyrolysis of rubber gloves in laboratory study was described. In order to visualize the practical application of rubber gloves pyrolysis in terms of treating rubber gloves in medical waste, a new test plant was designed and constructed. The semi-continuous test plant was designed to accommodate rubber gloves that were not cut or shredded. The test plant has a capacity of 2kg/ hr and employed auxiliary fuel instead of the conventional electrical power for heating. The concept was based on moving bed reactor, but additional feature of sand jacket feature was also introduced in the design. Pyrolysis of the gloves was conducted at three temperatures, namely 350 degree Celsius, 400 degree Celsius and 450 degree Celsius. Oxygen presents inside of the reactor due to the combined effect of imperfect sealing and suction effect. This study addresses the performance of this test plant covering the time temperature profile, gas evolution profile and product yield. Comparison between the yield of the liquid, gas and char pyrolyzate was made against the laboratory study. It was found that the oil yield was less than the one obtained from bench scale study. Water formation was more pronounced. The presence of the oxygen also altered the tail gas composition but eliminate the sticky nature of solid residue, making it easier to handle. The chemical composition of the oil was determined and the main compounds in the oil were esters and phtalic acid. (author)

  16. CURING AND MECHANICAL PROPERTIES OF CHLOROSULPHONATED POLYETHYLENE RUBBER BLEND

    Directory of Open Access Journals (Sweden)

    Jaroslava Budinski-Simendić

    2011-09-01

    Full Text Available In this paper, the curing and mechanical properties of two series of prepared blends, i.e., chlorosulphonated polyethylene (CSM/isobutylene-co-isoprene (IIR rubber blends and chlorosulphonated polyethylene (CSM/chlorinated isobutylene-co-isoprene (CIIR rubber blends were carried out. Blends were prepared using a two-roll mill at a temperature of 40-50 °C. The curing was assessed using a Monsanto oscillating disc rheometer R-100. The process of vulcanization accelerated sulfur of pure rubbers and their blends was carried out in an electrically heated laboratory hydraulic press under a pressure of about 4 MPa and 160 °C. The stress-strain experiments were performed using a tensile tester machine (Zwick 1425. Results indicate that the scorch time, ts2, and optimum cure time, tc90, increase with increasing CSM content in both blends. The value of modulus at 100 and 300% elongation and tensile strength increases with increasing CSM content, whereas elongation at break shows a decreasing trend. The enhancement in mechanical properties was supported by data of crosslink density in these samples obtained from swelling measurement and scanning electron microscopy studies of the rubber blends fractured surfaces

  17. Vibrations of turbine blades bundles model with rubber damping elements

    Czech Academy of Sciences Publication Activity Database

    Půst, Ladislav; Pešek, Luděk

    2014-01-01

    Roč. 21, č. 1 (2014), s. 45-52. ISSN 1802-1484 R&D Projects: GA ČR GA101/09/1166 Institutional support: RVO:61388998 Keywords : mathematical model * bundle of five blades * rubber damping elements * eigenmodes Subject RIV: BI - Acoustics http://www.engineeringmechanics.cz/obsahy.html?R=21&C=1

  18. Maleic anhydride grafting on EPDM rubber in the melt

    NARCIS (Netherlands)

    Oostenbrink, A.J.; Gaymans, R.J.

    1992-01-01

    The grafting of maleic anhydride on a EPDM rubber was studied with a twin screw extruder. The effect of barrel temperatures, throughput, maleic anhydride concentration and peroxide concentration [bis(t-butyl peroxy isopropyl)benzene] on the degree of grafting and melt viscosity was studied. The male

  19. Rapid Field Measurement of Rubber Content in Russian Dandelion

    Science.gov (United States)

    Natural rubber is a critical and strategic raw material for industrial manufacturing and national defense. In 2008, 10 million tons of NR were produced for commercial use, most of it from Hevea brasiliensis in tropical countries. The annual US import deficit for NR is approximately $1 billion. Devel...

  20. Degradation of nitrile rubber fuel hose by biodiesel use

    International Nuclear Information System (INIS)

    Nowadays biodiesel is becoming an increasingly important and popular fuel, obtained from renewable sources, and contributes to pollutant emissions reduction and decreasing fossil fuels dependence. However, its easier oxidation and faster degradation in comparison to diesel led to compatibility problems between biodiesel and various metallic and polymeric materials contacted. Therefore, the objective of this work is to investigate the effect of different mixtures diesel–biodiesel (fuel type B5, B10, B20) used in Baja California, Mexico on the resistance of nitrile rubber fuel hoses at temperatures of 25 °C and 70 °C applying gravimetric tests, tensile strength measurements and scanning electron microscopy analysis. The factors affecting the material mass change were identified using an experimental design analysis. It was found that the fuel temperature did not conduct to significant mass loss of nitrile rubber fuel hose, while biodiesel concentration affected the properties of the elastomer, causing the phenomenon of swelling. The exposure of hoses to fuel with increasing concentrations of biodiesel led to tensile strength decrease. - Highlights: • The biodiesel oxidation led to problems with polymeric materials. • The degradation of a nitrile rubber fuel hose in biodiesel blends was assessed. • The nitrile rubber showed greater affinity for biodiesel than diesel. • The elastomer swelled, cracked and lost its mechanical properties by biodiesel. • SEM analysis confirmed surface morphology changes in higher biodiesel blends