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Sample records for blue rubber bleb

  1. Blue rubber bleb nevus syndrome

    Directory of Open Access Journals (Sweden)

    Rodrigues Daleth

    2000-01-01

    Full Text Available The blue rubber nevus syndrome consists of multiple venous malformations in the skin and gastrointestinal tract associated with intestinal hemorrhage and iron deficiency anemia. Other organs may be involved. The causes of this syndrome are unknown. Its most common presentation is in the form of sporadic cases, but dominant autosomal inheritance has been described. It is a condition that affects both sexes equally, and its occurrence is rare in the black race. We present a case of this syndrome diagnosed in a 11-year-old patient. He had severe anemia and a venous swelling on the trunk. Similar lesions were found in the stomach, bowel, and on his foot. We emphasize the main clinical aspects: intestine, eyes, nasopharynx, parotids, lungs, liver, spleen, heart, brain, pleura, peritoneum, pericardium, skeletal muscles, bladder, and penis lesions, systemic complications that may occur to these patients which are thrombosis and calcification, as well as consumptive coagulopathy and thrombocytopenia that may occur within the nevi.

  2. Blue rubber bleb nevus syndrome coexisted with intestinal ...

    African Journals Online (AJOL)

    Blue Rubber Bleb Nevus Syndrome (BRBNS) is an uncommon congenital disorder characterized by sporadic venous malformation which mainly occurs in skin and alimentary canal. Here, we report a BRBNS patient with concomitant intestinal intussusception who diagnosed by intraoperative endoscopy and ultimately ...

  3. Blue rubber bleb naevus syndrome: A rare cause of gastrointestinal ...

    African Journals Online (AJOL)

    Blue rubber bleb naevus syndrome (BRBNS) is characterised by vascular malformations of the skin and gastrointestinal tract. We present the rare case of BRBNS in an African child. She presented with large-volume gastrointestinal bleeding and was managed by on-table colonoscopic identification and surgical excision, ...

  4. Severe Blue Rubber Bleb Nevus Syndrome in a Neonate

    DEFF Research Database (Denmark)

    Hansen, L; Wewer, V; Pedersen, S

    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...... 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...

  5. Blue rubber bleb nevus syndrome: case report Síndrome do blue rubber bleb nevus: relato de caso

    Directory of Open Access Journals (Sweden)

    Magaly Gemio Teixeira

    2003-01-01

    Full Text Available The case of a patient with blue rubber bleb nevus syndrome who is infected by acquired immunodeficiency syndrome virus due to multiple blood transfusions is presented. This case shows that although it is a rare systemic disorder, blue rubber bleb nevus syndrome has to be considered in the differential diagnosis of chronic anemia or gastrointestinal bleeding. Patients should be investigated by endoscopy, which is the most reliable method for detecting these lesions. The patient underwent gastroscopy and enteroscopy via enterotomy with identification of all lesions. Minimal resection of the larger lesions and string-purse suture of the smaller ones involving all the layers of the intestine were performed. The string-purse suture of the lesions detected by enteroscopy proved to be an effective technique for handling these lesions, avoiding extensive intestinal resection and stopping the bleeding. Effective management of these patients demands aggressive treatment and should be initiated as soon as possible to avoid risks involved in blood transfusions, as occurred in this case.É descrito um caso da síndrome do blue rubber bleb nevus associada a infecção pelo vírus da imunodeficiência adquirida em conseqüência de múltiplas transfusões de sangue. Este caso demonstra que, embora rara, esta síndrome deva ser considerada no diagnóstico diferencial da anemia crônica ou sangramento gastrointestinal. O melhor método diagnóstico é a endoscopia. A doente foi operada e submetida a esofagogastroduodenoscopia e endoscopia através de enterotomia com identificação de todas as lesões que foram tratadas, as maiores, por ressecção mínima e as demais por sutura em bolsa ao redor do nevo interessando toda a parede intestinal. A sutura em bolsa das lesões detectadas por enteroscopia demonstrou ser uma técnica efetiva no tratamento destas lesões, evitando assim ressecções intestinais extensas e parando o sangramento. O manuseio destes doentes

  6. 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.

  7. Severe Blue Rubber Bleb Nevus Syndrome in a Neonate

    DEFF Research Database (Denmark)

    Hansen, L; Wewer, V; Pedersen, S

    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...

  8. Sarcolemmal blebs and osmotic fragility as correlates of irreversible ischemic injury in preconditioned isolated rabbit cardiomyocytes.

    Science.gov (United States)

    Armstrong, S C; Shivell, L C; Ganote, C E

    2001-01-01

    The hypothesis that irreversible ischemic injury is related to sub-sarcolemmal blebbing and an inherent osmotic fragility of the blebs was tested by subjecting isolated control and ischemically preconditioned (IPC) or calyculin A (CalA)-pretreated (protected) rabbit cardiomyocytes to ischemic pelleting followed by resuspension in 340, 170 or 85 mosmol medium containing trypan blue. At time points from 0-240 min, osmotic fragility was assessed by the percentage of trypan blue permeable cells. Membrane blebs were visualized with India ink preparations. Bleb formation, following acute hypo-osmotic swelling, developed by 75 min and increased with longer periods of ischemia. Osmotic fragility developed only after 75 min. Cells resuspended in 340 mosmol media did not form blebs and largely retained the ability to exclude trypan blue, even after 240 min ischemia. Although the latent tendency for osmotic blebbing preceded the development of osmotic fragility, most osmotically fragile cells became permeable without evident sarcolemmal bleb formation. The onset of osmotic fragility was delayed in protected cells, but protection did not reduce the bleb formation. It is concluded that blebbing and osmotic fragility are independent manifestations of ischemic injury. The principal locus of irreversible ischemic injury and the protection provided by IPC may lie within the sarcolemma rather than at sarcolemmal attachments to underlying adherens junctions.

  9. 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.

  10. Bleb Revision With Temporalis Fascia Autograft.

    Science.gov (United States)

    Qu-Knafo, Lise; Le Du, Brivael; Boumendil, Julien; Nordmann, Jean-Philippe

    2017-01-01

    We report the first description of temporalis fascia autograft to repair a late leakage bleb with scleral defect that occurred long time after trabeculectomy with mitomycin C. A 65-year-old woman was referred to our hospital with chronic late bleb leakage on her right eye. She had previously undergone a trabeculectomy with mitomycin C 3 years ago for a pigmentary glaucoma. Bleb leakage occurred 1½ year after the initial surgery. She underwent 2 surgical revisions consisting of a conjunctival advancement then an autologous conjunctival with partial scleral grafts without success. The initial best-corrected visual acuity of the right eye was 20/50 (Snellen scale). Slit-lamp examination revealed an avascular filtering bleb with leakage (massive positive Seidel test) and a scleral defect. The anterior chamber was deep and intraocular pressure (IOP) was 9 mm Hg.Faced with the risk of blebitis, endophthalmitis, and with the failure of the previous surgeries announced earlier, a surgical revision with autologous superficial temporalis fascia graft was decided to repair the leaking bleb. After local anesthesia, a sample of superficial temporalis fascia was harvested. The necrotic avascular conjunctiva around the bleb was dissected to separate and excise it from the sclera. The autologous fascia graft was sutured on the scleral defect with 10-0 nylon. Subsequently healthy conjunctiva was sutured above the graft. No bleb leakage occurred postoperatively, best-corrected visual acuity improved to 20/25, and IOP remained within normal levels 6 months after surgery without IOP-lowering medication. Superficial temporalis fascia autograft seems to be an effective, safe, and easy technique for ophthalmologists. It is a new procedure in the management of late-onset bleb leakage.

  11. 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)

    Gupta, V.K.; Gupta, Bina; Rastogi, Arshi; Agarwal, Shilpi; Nayak, Arunima

    2011-01-01

    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.

  12. Hemodynamics before and after bleb formation in cerebral aneurysms

    Science.gov (United States)

    Cebral, Juan R.; Radaelli, Alessandro; Frangi, Alejandro; Putman, Christopher M.

    2007-03-01

    We investigate whether blebs in cerebral aneurysms form in regions of low or high wall shear stress (WSS), and how the intraaneurysmal hemodynamic pattern changes after bleb formation. Seven intracranial aneurysms harboring well defined blebs were selected from our database and subject-specific computational models were constructed from 3D rotational angiography. For each patient, a second anatomical model representing the aneurysm before bleb formation was constructed by smoothing out the bleb. Computational fluid dynamics simulations were performed under pulsatile flow conditions for both models of each aneurysm. In six of the seven aneurysms, the blebs formed in a region of elevated WSS associated to the inflow jet impaction zone. In one, the bleb formed in a region of low WSS associated to the outflow zone. In this case, the inflow jet maintained a fairly concentrated structure all the way to the outflow zone, while in the other six aneurysms it dispersed after impacting the aneurysm wall. In all aneurysms, once the blebs formed, new flow recirculation regions were formed inside the blebs and the blebs progressed to a state of low WSS. Assuming that blebs form due to a focally damaged arterial wall, these results seem to indicate that the localized injury of the vessel wall may be caused by elevated WSS associated with the inflow jet. However, the final shape of the aneurysm is probably also influenced by the peri-aneurysmal environment that can provide extra structural support via contact with structures such as bone or dura matter.

  13. Bleb incarceration following Ahmed valve surgery

    Directory of Open Access Journals (Sweden)

    Gross FJ

    2016-10-01

    Full Text Available Fredric J Gross, Giovanni DiSandro Department of Ophthalmology, Eastern Virginia Medical School, Norfolk, VA, USA Abstract: Globe luxation is a painful and potentially vision-threatening condition in which the globe becomes trapped behind the eyelids requiring physician intervention in the emergency department or eye clinic. On presentation, the patient typically complains of an inability to close their eye, severe foreign body sensation, decreased vision, and significant eye pain. Although most visual symptoms are reversible and primarily result from exposure keratopathy, optic nerve damage, and permanent vision loss can occur from repeat or prolonged episodes of globe luxation. Risk factors include any congenital or acquired conditions that displace the globe anteriorly in the orbit and increased eyelid laxity that allows the globe to prolapse through the lid aperture. Typically, the precipitating event involves eyelid retraction during ophthalmic examination or an event that increases intraorbital pressure such as coughing or sneezing. Once the globe has luxated, the condition is typically worsened by blepharospasm and patients’ attempts to close the eye that worsen the entrapment. In the current case, the patient had a large superotemporal filtering bleb following Ahmed valve surgery for uncontrolled glaucoma. While instilling her glaucoma medication, she retracted her eyelids sufficiently to pull the upper lid over her filtering bleb where it became entrapped causing a similar presentation to globe luxation. Traditional methods of repositioning the globe were unsuccessful. Bleb needling was ultimately required to return the globe to a normal position. Keywords: luxation, globe, glaucoma

  14. 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.

  15. Rescue of failed filtering blebs with ab interno trephination.

    Science.gov (United States)

    Shihadeh, Wisam A; Ritch, Robert; Liebmann, Jeffrey M

    2006-06-01

    We evaluated the effectiveness of ab interno automated trephination as a technique for rescuing failed mature filtering blebs. A retrospective chart review of 40 failed blebs of 38 patients who had a posttrephination follow-up period of at least 3 months was done. With success defined as intraocular pressure (IOP) control with other modalities of management. Complications were few. We believe that ab interno trephination is an excellent option for rescuing selected failed filtering blebs.

  16. 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.

  17. Histopathology and treatment of a huge overhanging filtering bleb.

    Science.gov (United States)

    Ou-Yang, Ping-Bo; Qi, Xin; Duan, Xuan-Chu

    2016-10-06

    The giant filtering bleb encroaching onto the corneal surface is a rare occurrence in our and other's clinical experience (Kapoor and Syed, Int. Ophthalmol 31(5):403-404, 2011), even in patients having had a trabeculectomy with mitomycin C, and how it developed is debated. In this paper, we report a patient who developed a huge overhanging filtering bleb after trabeculectomy, and present our intraoperative photographs, histopathology and immunohistochemistry results. A 62-year-old female visited our hospital due to the giant filtering bleb encroaching onto the corneal surface which was about 6 mm × 8 mm × 3 mm. We dissected the filtering bleb from the cornea and present the histopathology and immunohistochemistry results of it. The results from histopathology and immunohistochemistry in this study are consistent with the filtering cicatrix hypothesis. However, our finding that the overhanging blebs had tight connections with the corneal tissue or corneoscleral limbus, rather than simply leaning on it, might be highly related to their development and still needs to be further studied.

  18. Microtubule-Mediated Inositol Lipid Signaling Plays Critical Roles in Regulation of Blebbing.

    Directory of Open Access Journals (Sweden)

    Tatsuroh Sugiyama

    Full Text Available Cells migrate by extending pseudopods such as lamellipodia and blebs. Although the signals leading to lamellipodia extension have been extensively investigated, those for bleb extension remain unclear. Here, we investigated signals for blebbing in Dictyostelium cells using a newly developed assay to induce blebbing. When cells were cut into two pieces with a microneedle, the anucleate fragments vigorously extended blebs. This assay enabled us to induce blebbing reproducibly, and analyses of knockout mutants and specific inhibitors identified candidate molecules that regulate blebbing. Blebs were also induced in anucleate fragments of leukocytes, indicating that this assay is generally applicable to animal cells. After cutting, microtubules in the anucleate fragments promptly depolymerized, followed by the extension of blebs. Furthermore, when intact cells were treated with a microtubule inhibitor, they frequently extended blebs. The depolymerization of microtubules induced the delocalization of inositol lipid phosphatidylinositol 3,4,5-trisphosphate from the cell membrane. PI3 kinase-null cells frequently extended blebs, whereas PTEN-null cells extended fewer blebs. From these observations, we propose a model in which microtubules play a critical role in bleb regulation via inositol lipid metabolism.

  19. 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.

  20. Prospective study of filtering blebs after XEN45 surgery.

    Science.gov (United States)

    Olate-Pérez, Á; Pérez-Torregrosa, V T; Gargallo-Benedicto, A; Neira-Ibáñez, P; Cerdà-Ibáñez, M; Osorio-Alayo, V; Barreiro-Rego, A; Duch-Samper, A

    2017-08-01

    To qualitatively analyse the evolution of filtering blebs after XEN surgery, by using anterior segment optical coherence tomography (AS-OCT). A prospective study was performed on filtering blebs of 30 eyes with cataracts and glaucoma, surgically operated on using phacoemulsification and XEN45 implantation (PHACO-XEN). AS-OCT was used to analyse bleb morphology and reflectivity at 3, 6, and 12 months after surgery. Functionality was studied considering an intraocular pressure (IOP)≤18mmHg without antihypertensive medication. The IOP enabled the blebs to be classified into non-functional: flat (6.67%) and encapsulated (3.33%); and functional (90%), which were then divide by their morphology into cystic (5/27), diffuse (2/27), and layered (20/27). Cystic types had a mean IOP of 12.8, 12.6, and 14.0mmHg at 3, 6 and 12 months, respectively. In the diffuse type, the mean IOP was 13.0, 11.5 and 13.0mmHg at 3, 6 and 12 months, respectively. In the layers pattern the mean IOP was 14.45, 14.55 and 14.8mmHg at 3, 6 and 12 months respectively. The percentage of blebs with high reflectivity was 48.15%, 62.96%, and 77.78%, at 3, 6 and 12 months, with a mean IOP of 14.23, 14.59, and 15.14mmHg in each time period, respectively. AS-OCT could be a good predictor of bleb functionality in PHACO-XEN surgery. Those with a cystic pattern or low reflectivity seem to have better post-operative success. Nevertheless, more long-term studies are required. Copyright © 2017 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  1. 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

    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...

  2. Random blebbing motion: A simple model linking cell structural properties to migration characteristics

    Science.gov (United States)

    Woolley, Thomas E.; Gaffney, Eamonn A.; Goriely, Alain

    2017-07-01

    If the plasma membrane of a cell is able to delaminate locally from its actin cortex, a cellular bleb can be produced. Blebs are pressure-driven protrusions, which are noteworthy for their ability to produce cellular motion. Starting from a general continuum mechanics description, we restrict ourselves to considering cell and bleb shapes that maintain approximately spherical forms. From this assumption, we obtain a tractable algebraic system for bleb formation. By including cell-substrate adhesions, we can model blebbing cell motility. Further, by considering mechanically isolated blebbing events, which are randomly distributed over the cell, we can derive equations linking the macroscopic migration characteristics to the microscopic structural parameters of the cell. This multiscale modeling framework is then used to provide parameter estimates, which are in agreement with current experimental data. In summary, the construction of the mathematical model provides testable relationships between the bleb size and cell motility.

  3. A Case of Undesired Bleb Developed After Penetrating Injury

    Directory of Open Access Journals (Sweden)

    Cem Ozgonul

    2014-03-01

    Full Text Available Eighty-year-old male patient was admitted to our policlinic with stinging, burning and itching in both eyes. Ophthalmological examination revealed avascular undesired bleb that releated with anterior chamber at 2-3 hour quadrant nasal limbus with the surrounding corneal and conjunctival epithelium was vascularized and the dimension was 3x3x3 mm. Towards these findings, we questioned the patient again and we found that, 40 years ago, a broken part of the shaving razor had injured his eye. After penetrating injury of the eye, because of the sutured wound leakage, undesired bleb formations can be seen. We suggest that kind of patient shold be followed up to prevent late complications of penetrating injury.

  4. Excisional Bleb Revision for Management of Failed Ahmed Glaucoma Valve.

    Science.gov (United States)

    Eslami, Yadollah; Fakhraie, Ghasem; Moghimi, Sasan; Zarei, Reza; Mohammadi, Masoud; Nabavi, Amin; Yaseri, Mehdi; Izadi, Ali

    2017-12-01

    To evaluate the outcome of excisonal bleb revision in patients with failed Ahmed glaucoma valve (AGV). In total, 29 patients with uncontrolled intraocular pressure (IOP) despite of maximal tolerated medical therapy at least 6 months after AGV implantation were enrolled in this prospective interventional case series. Excision of fibrotic tissue around the reservoir with application of mitomycin C 0.02% was performed. IOP, number of glaucoma medications were evaluated at baseline and 1 week and 1, 3, 6, and 12 months postoperatively. Complete and qualified success was defined as IOP≤21 mm Hg with or without glaucoma medications, respectively. Intraoperative and postopervative complications were also recorded. Mean IOP was reduced from 30±4.2 mm Hg at baseline to 19.2±3.1 mm Hg at 12-month follow-up visit (Pglaucoma medications was decrease from 3.2±0.5 at baseline to 1.9±0.7 at 12-month follow-up (Pglaucoma surgeries were significantly associated with the failure of excisonal bleb revision. Excisional bleb revision could be considered as a relatively effective alternative option for management of inadequate IOP control after AGV implantation.

  5. A CROSS-SECTIONAL MORPHOLOGICAL AND FUNCTIONAL EVALUATION OF FILTERING BLEBS FIVE YEARS POST TRABECULECTOMY

    Directory of Open Access Journals (Sweden)

    Jyoti Shetty

    2017-06-01

    Full Text Available BACKGROUND After trabeculectomy, wound remodelling and fibrosis continues lifelong and can affect bleb filtration. Ethnicity plays an important role in wound healing. Wound modulation with Mitomycin C affects the morphology as well as long-term functional success of the bleb. The aim of the study is to assess the morphology of blebs 5 years post trabeculectomy using clinical methods (slit lamp biomicroscopy and Moorfields Bleb Grading System MBGS along with Anterior Segment Optical Coherence Tomography (ASOCT and to correlate it with its functional outcome. MATERIALS AND METHODS This prospective cross-sectional study evaluated 40 eyes of 30 patients who had undergone trabeculectomy with adjuvant mitomycin C and had a postoperative duration of 5 years or more. Following a comprehensive ophthalmic examination, grading of filtering bleb was performed using MBGS. Internal bleb morphology was imaged using AS-OCT. RESULTS At the time of surgery, the age of the patients ranged from 33-71 years. The average postoperative duration was 8.6 ± 3.3 years. Based on slit lamp biomicroscopy, we found that 47% of the total blebs were diffuse, 30% were cystic and 23% were flat. MBGS parameters were studied in relation to bleb type on slit lamp. Bleb height (p=0.001 and central bleb vascularity (p=0.010 were found to have statistically significant association. There is a statistically significant agreement between the bleb type on slit lamp examination and morphological classification based on AS-OCT at p<0.05 (p=0.000. We observed complete success in 90% of eyes and qualified success in 100%. IOP at the time of study was found to have negative correlation with total bleb height on AS-OCT (r: -0.3592; p=0.022909. CONCLUSION This case series with a long-term followup period showed that trabeculectomy augmented with Mitomycin C (MMC can achieve good long-term IOP control. The filtering bleb morphology using clinical methods (slit lamp biomicroscopy and MBGS and

  6. Late-Onset Inadvertent Bleb Formation following Pars Plana M3 Molteno Implant Tube Obstruction

    Directory of Open Access Journals (Sweden)

    Anmar M. Abdul-Rahman

    2017-01-01

    Full Text Available Purpose: To report a case of inadvertent bleb formation presenting 18 months after pars plana M3 Molteno implant tube obstruction in a patient with mixed mechanism glaucoma. Materials and Methods: An 84-year-old Caucasian male with mixed mechanism glaucoma underwent slit-lamp examination, gonioscopy, colour anterior segment photography and anterior segment optical coherence tomography (AS-OCT. Results: An inadvertent bleb developed 18 months after pars plana implant tube re-positioning with a 6/0 Vicryl tie ligature. The bleb was located in the area anterior to the implant plate; it was characterised by a thin, transparent, avascular and multi-cystic wall, with a visible stoma at the posterior edge of the bleb. The bleb was functioning as demonstrated by an intraocular pressure of 6 mm Hg at presentation and a punctate fluorescein uptake pattern of the bleb wall. The bleb over the plate of the Molteno implant was non-functioning, likely secondary to tube obstruction by vitreous in the early postoperative period. AS-OCT showed a tract from the anterior chamber commencing at an entry wound through a corneal tunnel to the posterior stoma at the base of the inadvertent bleb. Conclusions: We hypothesise that the pathophysiologic factors resulting in an inadvertent bleb are a result of a combination of apoptosis, late-onset wound dehiscence and internal gaping of a centrally placed corneal wound. In addition, aqueous hydrodynamic factors may play a role.

  7. Augmentation of filtering blebs with viscoelastics in trabeculectomy.

    Science.gov (United States)

    Jeong, Hyerin; Sung, Kyung Rim

    2014-10-01

    To evaluate the clinical outcome of viscoelastics (VE, sodium hyaluronate)-augmented trabeculectomy (VAT, 66 eyes) and conventional trabeculectomy (CT, 57 eyes) for glaucomatous eyes. In the VAT group, half of the anterior chamber space was filled with VE via the paracentesis site at the end of CT and a balanced salt solution was injected into the anterior chamber. This procedure induced migration of VE from the anterior chamber into the bleb space; thus the bleb was elevated with underlying VE. Follow-up examinations were performed until 1 year after surgery. Success was defined as the attainment of an intraocular pressure (IOP) greater than 5 mmHg and less than 22 mmHg. If IOP was in the range of success without antiglaucoma medication, it was regarded as a complete success. The mean postoperative IOP was significantly lower in the VAT group at postoperative 1 day, 1 week, and 1 month. The complete success rate was significantly higher in the VAT group (89%) than in the CT group (75%), though the qualified success rate was not different between the two groups. The number of IOP-lowering medications at postoperative 1 year was significantly higher in the CT group (1.30 ± 1.08 vs. 0.73 ± 0.98, p = 0.003). Among postoperative procedures, laser suture lysis was required less frequently in the VAT group (p < 0.001). Placing VE within the bleb at the end of surgery may result in better IOP control and less need for IOP-lowering medication without any additional materials, cost, or time.

  8. Rubber compounding and processing

    CSIR Research Space (South Africa)

    John, MJ

    2014-06-01

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

  9. 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.

  10. MRTF transcription and Ezrin-dependent plasma membrane blebbing are required for entotic invasion.

    Science.gov (United States)

    Hinojosa, Laura Soto; Holst, Manuel; Baarlink, Christian; Grosse, Robert

    2017-10-02

    Entosis is a nonapoptotic form of cell death initiated by actomyosin-dependent homotypic cell-in-cell invasion that can be observed in malignant exudates during tumor progression. We previously demonstrated formin-mediated actin dynamics at the rear of the invading cell as well as nonapoptotic plasma membrane (PM) blebbing in this cellular motile process. Although the contractile actin cortex involved in bleb-driven motility is well characterized, a role for transcriptional regulation in this process has not been studied. Here, we explore the impact of the actin-controlled MRTF-SRF (myocardin-related transcription factor-serum response factor) pathway for sustained PM blebbing and entotic invasion. We find that cortical blebbing is tightly coupled to MRTF nuclear shuttling to promote the SRF transcriptional activity required for entosis. Furthermore, PM blebbing triggered SRF-mediated up-regulation of the metastasis-associated ERM protein Ezrin. Notably, Ezrin is sufficient and important to sustain bleb dynamics for cell-in-cell invasion when SRF is suppressed. Our results highlight the critical role of the actin-regulated MRTF transcriptional pathway for bleb-associated invasive motility, such as during entosis. © 2017 Soto Hinojosa et al.

  11. 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.

  12. Bleb Expansion in Migrating Cells Depends on Supply of Membrane from Cell Surface Invaginations.

    Science.gov (United States)

    Goudarzi, Mohammad; Tarbashevich, Katsiaryna; Mildner, Karina; Begemann, Isabell; Garcia, Jamie; Paksa, Azadeh; Reichman-Fried, Michal; Mahabaleshwar, Harsha; Blaser, Heiko; Hartwig, Johannes; Zeuschner, Dagmar; Galic, Milos; Bagnat, Michel; Betz, Timo; Raz, Erez

    2017-12-04

    Cell migration is essential for morphogenesis, organ formation, and homeostasis, with relevance for clinical conditions. The migration of primordial germ cells (PGCs) is a useful model for studying this process in the context of the developing embryo. Zebrafish PGC migration depends on the formation of cellular protrusions in form of blebs, a type of protrusion found in various cell types. Here we report on the mechanisms allowing the inflation of the membrane during bleb formation. We show that the rapid expansion of the protrusion depends on membrane invaginations that are localized preferentially at the cell front. The formation of these invaginations requires the function of Cdc42, and their unfolding allows bleb inflation and dynamic cell-shape changes performed by migrating cells. Inhibiting the formation and release of the invaginations strongly interfered with bleb formation, cell motility, and the ability of the cells to reach their target. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Rubber glove wearing device

    International Nuclear Information System (INIS)

    Nozaki, Tatsuo; Takada, Kaoru.

    1994-01-01

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

  14. Two cases of spontaneous filtering blebs, one idiopathic and one associated with Terrien marginal degeneration.

    Science.gov (United States)

    Munro, Monique; McWhae, John; Romanchuk, Kenneth; Crichton, Andrew; Carter, Gordon; Ball, Arlene

    2014-07-01

    To report a case of an idiopathic unilateral filtering bleb in an otherwise well patient and a case of bilateral spontaneous filtering blebs in association with Terrien marginal degeneration. In this retrospective observational study of 2 cases, clinical notes, ultrasound biomicroscopy and gonioscopy images were reviewed. Case 1: A 32-year-old woman presented with a 1-year history of a gradually growing cyst in her right eye. No changes in vision were reported. The patient had no previous ocular or systemic history, trauma, or surgical interventions. Slit-lamp examination revealed a multilobulated cyst at the supranasal limbus OD. Diagnosis was an idiopathic spontaneous limbal filtering bleb of unclear etiology because there was no inciting event or obvious cause. Case 2: A 31-year-old man, with 2 past episodes of spontaneous filtering bleb development, affecting the left, then the right, eye, presented with his third event in May 2012. The visual acuity was decreased to 20/400 OD. The right eye was hypotonous and ultrasound biomicroscopy confirmed a shallow anterior chamber, a superior peripheral corneal defect, and an echolucent space suggestive of subconjunctival fluid. Limbal thinning was noted bilaterally, consistent with Terrien marginal degeneration. This is a rare case of an idiopathic filtering bleb occurring in a healthy patient with no precipitating cause, other ocular abnormalities, or physical malformations, and the only reported case of bilateral sequential filtering blebs associated with an atypical presentation of Terrien marginal degeneration.

  15. 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...

  16. Prompt 27-gauge sutureless transconjunctival vitrectomy for bleb-associated endophthalmitis.

    Science.gov (United States)

    Xiao, Bo; Yang, Jin; Chu, Yanhua; Han, Quanhong

    2017-10-23

    To summarize the characters of 6 bleb-associated endophthalmitis (BAE) cases and to report the outcomes of prompt 27-gauge sutureless transconjunctival vitrectomy to treat these cases. Retrospective, non-randomized, consecutive case series of patients diagnosed with bleb-associated endophthalmitis who underwent prompt 27-gauge vitrectomy. The interval to get bleb-associated endophthalmitis from previous surgery was variant from 2 weeks to 36 months. Most of the patients experienced eye pain. The visual acuity was affected quickly. All the patients presented with hypopyon, fibrinous reaction, and vitreous wick. The size of the hypopyon was from 2 to 4 mm. Two patients came with intraocular lenses. Prompt 27-gauge sutureless transconjunctival vitrectomy was performed on all patients with bleb-associated endophthalmitis. None of the patients experienced complications of sutureless vitrectomy such as hypotony or wound leak. The improvement of best corrected visual acuity (BCVA) was significant in four of six patients. The improvement of BCVA was statistically calculated by using logMAR VA (p  21 mmHg) and received pressure-lowering agents. BAE is associated with substantial visual morbidity. Prompt 27-gauge sutureless transconjunctival vitrectomy is an effective and safe way for treating bleb-associated endophthalmitis.

  17. Clinical observation of needle revision and 5-fluorouracil subconjunctive injection for the dysfunctional filtering blebs

    Directory of Open Access Journals (Sweden)

    Yan-Hua Gao

    2016-07-01

    Full Text Available AIM:To investigate the efficacy and safety of needle revision with 5-fluorouracil(5-FUon the dysfunctional filtering blebs after trabeculectomy and to assess the factors that may impact the success. METHODS:Eighty-three eyes in 76 patients underwent the needle revision and 5-FU subconjunctive injection for the dysfunctional blebs after trabeculectomy and were followed up for 12mo. The intraocular pressure(IOP, the number of drugs, corneal endothclium, bleb morphology and complications were observed and recorded. RESULTS:IOP decreased significantly from 35.3±5.8mmHg(1kPa=7.5mmHgof pre-needling to 17.0±4.3mmHg of post-needling(PPCI: 10.3-11.6. Statistically, there were no significant difference on needling effect with reference to the types of glaucoma, the use of mitomycin C(MMCduring the previous filtration surgery, the ages of patients, the intervals of needling operation from previous trabeculectomy, while there were significant difference on needling effect with reference to bleb appearance before needling, and the mean number of needling in patients that had surgery within 3mo were less than those who had surgery for more than 3mo. CONCLUSION: The needle revision combined with 5-FU is a safe, effective and simple method. Dysfunctional blebs should be treated early after trabeculectomy.

  18. Hepatocyte membrane injury and bleb formation following low dose comfrey toxicity in rats.

    Science.gov (United States)

    Yeong, M L; Wakefield, S J; Ford, H C

    1993-04-01

    Comfrey, a popular herbal remedy, contains hepatotoxic pyrrolizidine alkaloids and has been implicated in recent human toxicity. Although alkaloids from other plant sources have been extensively researched, studies on the hepatotoxic effects of comfrey alkaloids are scant. The effects of high dose comfrey toxicity have been studied and the present investigation was undertaken to identify changes associated with relatively low dose toxicity. Eight young adult rats were dosed weekly for six weeks with 50 mg/kg of comfrey derived alkaloids. The animals were dissected one week after the last dose and the livers examined by light and electron microscopy. Changes at the light microscopic level showed vascular congestion, mild zone 3 necrosis and loss of definition of hepatocyte cellular membranes. Extensive ultrastructural abnormalities were identified in the form of endothelial sloughing and the loss of hepatocyte microvilli. A striking finding was florid bleb formation on the sinusoidal borders of hepatocytes. Many blebs were shed into the space of Disse and extruded to fill, and sometimes occlude, sinusoidal lumina. Platelets were frequently found in areas of bleb formation. There was evidence of late damage in collagenization of Disse's space. Hepatocyte bleb formation is known to occur under a variety of pathological conditions but there is little to no information in the literature on the effects, if any, of bleb formation on fibrogenesis and the microcirculation and its role in the pathogenesis of liver disease. The pyrrolizidine alkaloids of comfrey may serve as an experimental tool to study the process of bleb formation and the intimate relationship between hepatocyte and sinusoidal injury in the liver.

  19. Blebbing as a physical force in cancer EMT - parallels with mitosis.

    Science.gov (United States)

    Sekyrova, Petra; Östblom, Joel; Andäng, Michael

    2012-10-01

    Epithelial to mesenchymal transition (EMT) during metastasis is initially a two-step process beginning with delamination of cells from the solid tumor followed by acquisition of a migratory phenotype. Several reports indicate that plasma membrane blebbing, associated with cell division, coincides with cell delamination during developmental EMT. This raises a speculative question if blebbing drives EMT in cancer cells in a similar way. Here, we review available data on factors and processes that may support such a connection. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Bilateral idiopathic spontaneous filtering bleb with ectopia lentis: A case report and review of literature

    Directory of Open Access Journals (Sweden)

    Premanand Chandran

    2018-01-01

    Full Text Available A 26-year-old male presented with superior filtering bleb with scleral thinning, dislocated lens, and hypotony in both the eyes. His cornea was normal without any sign of ectasia, and there was no history of recurrent redness, trauma, or surgery in either eye. Anterior segment optical coherence tomography did not reveal communicating fistula between the anterior chamber and subconjunctival space. Physical examination and blood investigations did not reveal any systemic association. He was diagnosed to have spontaneous filtering bleb, which is a rare condition observed with ocular or systemic abnormalities.

  1. Vulcanization of Rubber

    Indian Academy of Sciences (India)

    'Volcanising done here' or some variant of this is a common sign displayed on roadside sheds. We all know that some treatment is done to rubber to improve its properties. But what exactly is the chemical process that is carried out? How does it alter the structure of rubber at the molecular level? How can these changes.

  2. Biodiversity in rubber agroforests

    NARCIS (Netherlands)

    Beukema, Hendrien

    2013-01-01

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

  3. Vulcanization of Rubber

    Indian Academy of Sciences (India)

    development of cracks in rubber, making the resulting products unusable. Once vulcanization begins, it ... polymer chain of rubber in an interesting fashion. Via the formation of a cyclic 6-membered transition state a sulfide unit is transferred to the polymer chain. This. Box 2. The mechanism of vulcanization is fairly complex.

  4. An ezrin-rich, rigid uropod-like structure directs movement of amoeboid blebbing cells.

    Science.gov (United States)

    Lorentzen, Anna; Bamber, Jeffrey; Sadok, Amine; Elson-Schwab, Ilan; Marshall, Christopher J

    2011-04-15

    Melanoma cells can switch between an elongated mesenchymal-type and a rounded amoeboid-type migration mode. The rounded 'amoeboid' form of cell movement is driven by actomyosin contractility resulting in membrane blebbing. Unlike elongated A375 melanoma cells, rounded A375 cells do not display any obvious morphological front-back polarisation, although polarisation is thought to be a prerequisite for cell movement. We show that blebbing A375 cells are polarised, with ezrin (a linker between the plasma membrane and actin cytoskeleton), F-actin, myosin light chain, plasma membrane, phosphatidylinositol (4,5)-bisphosphate and β1-integrin accumulating at the cell rear in a uropod-like structure. This structure does not have the typical protruding shape of classical leukocyte uropods, but, as for those structures, it is regulated by protein kinase C. We show that the ezrin-rich uropod-like structure (ERULS) is an inherent feature of polarised A375 cells and not a consequence of cell migration, and is necessary for cell invasion. Furthermore, we demonstrate that membrane blebbing is reduced at this site, leading to a model in which the rigid ezrin-containing structure determines the direction of a moving cell through localised inhibition of membrane blebbing.

  5. Characterisation of surface blebbing and membrane vesicles produced by Flavobacterium psychrophilum

    DEFF Research Database (Denmark)

    Møller, Jeannette Dan; Barnes, A.C.; Dalsgaard, Inger

    2005-01-01

    (LPS) or lipooligosaccharides (LOS) were associated with the MVs. Only the MVs of the HA+ strain possessed haemagglutinin activity. These findings suggest that the F. psychrophilum may, through surface blebbing, release antigenic MVs that contain some proteolytic activity and may aid the bacterium...... in releasing nutrients from its surrounding environment as well as playing a role in impeding the immune response of its host...

  6. 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

  7. Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy.

    Science.gov (United States)

    Esfandiari, Hamed; Pakravan, Mohammad; Loewen, Nils A; Yaseri, Mehdi

    2017-01-01

    Background : To determine the predictive value of postoperative bleb morphological features and intraocular pressure (IOP) on the success rate of trabeculectomy. Methods : In this prospective interventional case series, we analyzed for one year 80 consecutive primary open angle glaucoma patients who underwent mitomycin-augmented trabeculectomy. Bleb morphology was scored using the Indiana bleb appearance grading scale (IBAGS). Success was defined as IOP ≤15 mmHg at 12 months. We applied a multivariable regression analysis and determined the area under the receiver operating characteristic curve (AUC). Results : The mean age of participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430) with equal gender distribution (P=0.911). IOPs on day 1, 7 and 30 were similar in both (P= 0.193, 0.639, and 0.238, respectively.) The AUC of IOP at day 1, day 7 and 30 for predicting a successful outcome was 0.355, 0.452, and 0.80, respectively. The AUC for bleb morphology parameters of bleb height, extension, and vascularization, on day 14 were 0.368, 0.408, and 0.549, respectively. Values for day 30 were 0.428, 0.563, and 0.654. IOP change from day 1 to day 30 was a good predictor of failure (AUC=0.838, 95% CI: 0.704 to 0.971) with a change of more than 3 mmHg predicting failure with a sensitivity of 82.5% (95% CI: 68 to 91%) and a specificity of 87.5% (95% CI: 53 to 98%). Conclusions : IOP on day 30 had a fair to good accuracy while bleb features failed to predict success except bleb vascularity that had a poor to fair accuracy.  An IOP increase more than 3 mmHg during the first 30 days was a good predictor of failure.

  8. 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

  9. 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.

  10. Volumetric Measurement of Subretinal Blebs Using Microscope-Integrated Optical Coherence Tomography.

    Science.gov (United States)

    Hsu, S Tammy; Gabr, Hesham; Viehland, Christian; Sleiman, Karim; Ngo, Hoan T; Carrasco-Zevallos, Oscar M; Vajzovic, Lejla; McNabb, Ryan P; Stinnett, Sandra S; Izatt, Joseph A; Kuo, Anthony N; Toth, Cynthia A

    2018-04-01

    We advance studies of subretinal treatments by developing a microscope-integrated optical coherence tomography (MIOCT) image-based method for measuring the volume of therapeutics delivered into the subretinal space. A MIOCT image-based volume measurement method was developed and assessed for accuracy and reproducibility by imaging an object of known size in model eyes. This method then was applied to subretinal blebs created by injection of diluted triamcinolone. Bleb volumes obtained from MIOCT were compared to the intended injection volume and the surgeon's estimation of leakage. Validation of the image-based volume measurement method showed accuracy to ±1.0 μL (6.0% of measured volume) with no statistically significant variation under different imaging settings. When this method was applied to subretinal blebs, four of 11 blebs without surgeon-observed leakage yielded a mean volume of 32 ± 12.5 μL, in contrast to the intended 50 μL volume injected from the delivery device. This constituted a mean difference of -18 μL (mean percent error, 36 ± 25%). For all 11 blebs, the surgeon's estimations of leakage were significantly different from and showed no correlation with the volume loss based on image-based volume measurements ( P < 0.001, paired t -test; intraclass correlation = 0). We validated an accurate and reproducible method for measuring subretinal volumes using MIOCT. Use of this method revealed that the intended volume might not be delivered into the subretinal space. MIOCT can allow for accurate assessment of subretinal dose delivered, which may have therapeutic implications in evaluating the efficacy and toxicity of subretinal therapies. Use of MIOCT can provide feedback on the accuracy of subretinal injection volumes delivered.

  11. Boron-Loaded Silicone Rubber Scintillators

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-05-12

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

  12. US rubber markets recover

    International Nuclear Information System (INIS)

    Wood, A.

    1993-01-01

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

  13. 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.

  14. 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

  15. Theory of powdery rubber wear.

    Science.gov (United States)

    Persson, B N J

    2009-12-02

    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.

  16. Theory of powdery rubber wear

    Energy Technology Data Exchange (ETDEWEB)

    Persson, B N J [IFF, FZ-Juelich, 52425 Juelich (Germany)

    2009-12-02

    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 PHI(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.

  17. Pneumoconiosis in rubber workers

    International Nuclear Information System (INIS)

    Shirono, Ryozo; Yoshida, Shusaku

    1987-01-01

    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)

  18. Boron-Loaded Silicone Rubber Scintillators

    CERN Document Server

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

    2003-01-01

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

  19. 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

  20. Blue lesions.

    Science.gov (United States)

    Longo, Caterina; Scope, Alon; Lallas, Aimilios; Zalaudek, Iris; Moscarella, Elvira; Gardini, Stefano; Argenziano, Giuseppe; Pellacani, Giovanni

    2013-10-01

    Blue color is found in a wide range of malignant and benign melanocytic and nonmelanocytic lesions and in lesions that result from penetration of exogenous materials, such as radiation or amalgam tattoo or traumatic penetration of particles. Discriminating between different diagnostic entities that display blue color relies on careful patient examination and lesion assessment. Dermoscopically, the extent, distribution, and patterns created by blue color can help diagnose lesions with specificity and differentiate between benign and malignant entities. This article provides an overview of the main diagnoses whereby blue color can be found, providing simple management rules for these lesions. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Deterioration Assessment of Bridge Rubber Bearings

    OpenAIRE

    Gu, Haosheng; 伊藤, 義人; Itoh, Yoshito

    2005-01-01

    Natural rubber (NR) with lead plugs and high damping rubber (HDR) are often used for base-isolated rubber bearings. However, it is usually known that ageing causes rubber performance to drop. This research is to study the deterioration characteristics of these two kinds of bridge rubber bearings through accelerated thermal oxidation tests. The property variations inside the aged rubber blocks are investigated. For natural rubber bearing, the mechanical properties on the surface change the mos...

  2. Vulcanization of Rubber

    Indian Academy of Sciences (India)

    Vulcanization of Rubber - How to Alter Molecular Structure and Influence Physical Properties. Ch S S R Kumar Avinash M Nijasure. General Article Volume 2 Issue 4 April 1997 pp 55-59. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/04/0055-0059. Author Affiliations.

  3. Lamellipodia and Membrane Blebs Drive Efficient Electrotactic Migration of Rat Walker Carcinosarcoma Cells WC 256.

    Science.gov (United States)

    Sroka, Jolanta; Krecioch, Izabela; Zimolag, Eliza; Lasota, Slawomir; Rak, Monika; Kedracka-Krok, Sylwia; Borowicz, Pawel; Gajek, Marta; Madeja, Zbigniew

    2016-01-01

    The endogenous electric field (EF) may provide an important signal for directional cell migration during wound healing, embryonic development and cancer metastasis but the mechanism of cell electrotaxis is poorly understood. Additionally, there is no research addressing the question on the difference in electrotactic motility of cells representing various strategies of cell movement-specifically blebbing vs. lamellipodial migration. In the current study we constructed a unique experimental model which allowed for the investigation of electrotactic movement of cells of the same origin but representing different modes of cell migration: weakly adherent, spontaneously blebbing (BC) and lamellipodia forming (LC) WC256 cells. We report that both BC and LC sublines show robust cathodal migration in a physiological EF (1-3 V/cm). The directionality of cell movement was completely reversible upon reversing the field polarity. However, the full reversal of cell direction after the change of EF polarity was much faster in the case of BC (10 minutes) than LC cells (30 minutes). We also investigated the distinct requirements for Rac, Cdc42 and Rho pathways and intracellular Ca2+ in electrotaxis of WC256 sublines forming different types of cell protrusions. It was found that Rac1 is required for directional movement of LC to a much greater extent than for BC, but Cdc42 and RhoA are more crucial for BC than for LC cells. The inhibition of ROCK did not affect electrotaxis of LC in contrast to BC cells. The results also showed that intracellular Ca2+ is essential only for the electrotactic reaction of BC cells. Moreover, inhibition of MLCK and myosin II did not affect the electrotaxis of LC in contrast to BC cells. In conclusion, our results revealed that both lamellipodia and membrane blebs can efficiently drive electrotactic migration of WC 256 carcinosarcoma cells, however directional migration is mediated by different signalling pathways.

  4. Lamellipodia and Membrane Blebs Drive Efficient Electrotactic Migration of Rat Walker Carcinosarcoma Cells WC 256.

    Directory of Open Access Journals (Sweden)

    Jolanta Sroka

    Full Text Available The endogenous electric field (EF may provide an important signal for directional cell migration during wound healing, embryonic development and cancer metastasis but the mechanism of cell electrotaxis is poorly understood. Additionally, there is no research addressing the question on the difference in electrotactic motility of cells representing various strategies of cell movement-specifically blebbing vs. lamellipodial migration. In the current study we constructed a unique experimental model which allowed for the investigation of electrotactic movement of cells of the same origin but representing different modes of cell migration: weakly adherent, spontaneously blebbing (BC and lamellipodia forming (LC WC256 cells. We report that both BC and LC sublines show robust cathodal migration in a physiological EF (1-3 V/cm. The directionality of cell movement was completely reversible upon reversing the field polarity. However, the full reversal of cell direction after the change of EF polarity was much faster in the case of BC (10 minutes than LC cells (30 minutes. We also investigated the distinct requirements for Rac, Cdc42 and Rho pathways and intracellular Ca2+ in electrotaxis of WC256 sublines forming different types of cell protrusions. It was found that Rac1 is required for directional movement of LC to a much greater extent than for BC, but Cdc42 and RhoA are more crucial for BC than for LC cells. The inhibition of ROCK did not affect electrotaxis of LC in contrast to BC cells. The results also showed that intracellular Ca2+ is essential only for the electrotactic reaction of BC cells. Moreover, inhibition of MLCK and myosin II did not affect the electrotaxis of LC in contrast to BC cells. In conclusion, our results revealed that both lamellipodia and membrane blebs can efficiently drive electrotactic migration of WC 256 carcinosarcoma cells, however directional migration is mediated by different signalling pathways.

  5. Subcapsular sinus macrophage fragmentation and CD169+ bleb acquisition by closely associated IL-17-committed innate-like lymphocytes.

    Directory of Open Access Journals (Sweden)

    Elizabeth E Gray

    Full Text Available Subcapsular sinus macrophages (SSMs in lymph nodes are rapidly exposed to antigens arriving in afferent lymph and have a role in their capture and display to B cells. In tissue sections SSMs exhibit long cellular processes and express high amounts of CD169. Here, we show that many of the cells present in lymph node cell suspensions that stain for CD169 are not macrophages but lymphocytes that have acquired SSM-derived membrane blebs. The CD169 bleb(+ lymphocytes are enriched for IL-17 committed IL-7Rα(hiCCR6(+ T cells and NK cells. In addition, the CD169 staining detected on small numbers of CD11c(hi dendritic cells is frequently associated with membrane blebs. Counter intuitively the CD169 bleb(+ lymphocytes are mostly CD4 and CD8 negative whereas many SSMs express CD4. In situ, many IL-7Rα(hi cells are present at the subcapsular sinus and interfollicular regions and migrate in close association with CD169(+ macrophages. These findings suggest SSMs undergo fragmentation during tissue preparation and release blebs that are acquired by closely associated cells. They also suggest an intimate crosstalk between SSMs and IL-17 committed innate-like lymphocytes that may help provide early protection of the lymph node against lymph-borne invaders.

  6. Topical Mitomycin-C versus Subconjunctival 5‑Fluorouracil for Management of Bleb Failure

    Directory of Open Access Journals (Sweden)

    Mohammad Pakravan

    2011-01-01

    Full Text Available Purpose: To compare the efficacy and safety of topical mitomycin‑C (MMC drops with that of subconjunctival 5‑fluorouracil (5‑FU injections for management of early bleb failure after trabeculectomy or combined phacoemulsification and trabeculectomy with posterior chamber intraocular lens implantation (PT+PCIOL. Methods: In a randomized comparative study, 37 eyes of 37 patients with impending early bleb failure received MMC 0.02% eye drops for 2 or 4 weeks (19 eyes or subconjunctival 5‑FU injections, 5 mg per dose (18 eyes. Complete success was defined as 5 < IOP ≤ 18 mmHg without medications. Results: Baseline characteristics were comparable between the study groups. However, there were more cases of combined PT+PCIOL in the MMC group [11 (57.9% eyes versus 3 (16.7% eyes, P = 0.017]. Mean preoperative IOP was 20.5΁8.85 mmHg in the MMC group and 25.82΁11.35 mmHg in the 5‑FU group (P = 0.129, which was decreased to 13.2΁6.1 and 10.6΁4.8 mmHg respectively after 12 months (P = 0.159. There was no significant difference between the study groups in terms of bleb extent (P = 0.170, height (P = 0.178 or vascularity (P = 0.366. At the end of the study, complete success was achieved in 13 eyes (68.4% in the MMC group and 14 eyes (77.8% in the 5‑FU group (P = 0.714. The survival of success at 8 months (median follow-up was 89.5% and 86.5% in the MMC and 5‑FU groups respectively; the number of glaucoma medications (P = 0.707 and best-corrected visual acuity (P = 0.550 were also comparable. Complication rates were similar in the study groups (P = 0.140. Conclusion: Topical MMC 0.02% has comparable safety and efficacy to subconjunctival 5‑FU injections for management of early bleb failure. Topical MMC 0.02% drops are more convenient and can be initiated first, while 5‑FU injections may be reserved for eyes with an insufficient response to topical MMC.

  7. Efficacy of autologous conjunctival flap on repairing the late-onset filtering bleb leakage

    Directory of Open Access Journals (Sweden)

    Jian-Gang Xu

    2018-04-01

    Full Text Available AIM: To evaluate the effectiveness of autologous conjunctival flap surgery for repairing the late-onset filtering bleb leakage after trabeculectomy. METHODS: This study retrospectively reviewed 106 eyes from 106 patients with late-onset filtering bleb leakage after trabeculectomy who received autologous conjunctival flap surgery at the Zhongshan Ophthalmic Centre from 2005 to 2015. The basic information was recorded, and the interval time between trabeculectomy and autologous conjunctival flap surgery as well as related risk factors, intraocular pressure (IOP, anterior chamber depth (ACD and best corrected visual acuity (BCVA were analysed. Moreover, 41 patients who completed the 1-year follow up were analysed to determine the IOP and BCVA changes and long-term success rates. RESULTS: The 50 male and 56 female subjects (average age 39.13±17.96y included 47 (44.34% and 33 (31.13% cases of primary open angle and primary angle-closure glaucoma. The mean interval between trabeculectomy and repair surgery was 60.60±56.92 (3-264mo. The mean mitomycin (MMC concentration during trabeculectomy was 0.27±0.04 (0.12-0.4 mg/mL in the fornix-based conjunctival flap group (68 patients and 0.28±0.04 (0.20-0.33 mg/mL in the limbal-based conjunctival flap group (11 patients. After bleb leakage, the patients' vision remained stable while the IOP decreased from 10.25±4.76 (3-20.86 to 9.44±4.33 (2-21 mm Hg (P<0.01. In the 41 analysed patients, the IOP was controlled at 15.68±5.11 (7-40 mm Hg in the 1st year after autologous conjunctival flap surgery and recurrence was not observed, for a long-term success rate of 100%. CONCLUSION: Autologous conjunctival flap repairing surgery is an effective technique for sealing filtering bleb leakages and controlling IOP postoperatively.

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

    Science.gov (United States)

    Valiya Veettil, Mohanan; Sadagopan, Sathish; Kerur, Nagaraj; Chakraborty, Sayan; Chandran, Bala

    2010-12-23

    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 containing c

  9. 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

    2010-12-01

    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

  10. QENS investigation of filled rubbers

    CERN Document Server

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

    2002-01-01

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

  11. Seasonal Variation in the Incidence of Late-onset Bleb-related Infection After Filtering Surgery in Japan: The Japan Glaucoma Society Survey of Bleb-related Infection Report 3.

    Science.gov (United States)

    Sagara, Hideto; Yamamoto, Tetsuya; Sekiryu, Tetsuju; Ogasawara, Masashi; Tango, Toshiro

    2016-01-01

    To investigate seasonal variations in the incidence of late-onset bleb-related infection after filtering surgery in Japan and the relationship between season and other factors. This multicenter, prospective study is part of a 5-year-long Japan Glaucoma Society survey of bleb-related infection. We analyzed 156 cases of first-time infections (106 men, 50 women) encountered over 5 years to determine the seasonal variation using the Roger test and the relationships between season, sex, and age by logistic regression analysis. We noted significant monthly seasonal variation in the incidence of infection, which was the highest in January and February (23 and 18 infections, respectively; P=0.018) and lowest from August to November (9, 9, 11, and 8 infections, in that order). Multiple logistic regression analysis revealed that infections were most frequent among women in spring (odds ratio, 8.43; P=0.005). Staphylococcus aureus and Streptococcus spp. infections were more frequent in warmer seasons than in winter. Less virulent species, namely, coagulase-negative Staphylococcus spp., Corynebacterium spp., and Enterococcus spp., were frequently detected in winter. Coagulase-negative Staphylococcus spp. and Haemophilus influenzae were more frequent in women and men, respectively. The incidence of late-onset bleb-related infection showed significant seasonal variation and sex differences. The climate in Japan may influence the incidence of bleb-related infection. Moreover, besides climate, physical activity level and lifestyle may contribute to the seasonal variation in the incidence and sex differences in the involved bacterial agents of bleb-related infections in Japan.

  12. ROCK-1 mediates diabetes-induced retinal pigment epithelial and endothelial cell blebbing: Contribution to diabetic retinopathy.

    Science.gov (United States)

    Rothschild, Pierre-Raphaël; Salah, Sawsen; Berdugo, Marianne; Gélizé, Emmanuelle; Delaunay, Kimberley; Naud, Marie-Christine; Klein, Christophe; Moulin, Alexandre; Savoldelli, Michèle; Bergin, Ciara; Jeanny, Jean-Claude; Jonet, Laurent; Arsenijevic, Yvan; Behar-Cohen, Francine; Crisanti, Patricia

    2017-08-18

    In diabetic retinopathy, the exact mechanisms leading to retinal capillary closure and to retinal barriers breakdown remain imperfectly understood. Rho-associated kinase (ROCK), an effector of the small GTPase Rho, involved in cytoskeleton dynamic regulation and cell polarity is activated by hyperglycemia. In one year-old Goto Kakizaki (GK) type 2 diabetic rats retina, ROCK-1 activation was assessed by its cellular distribution and by phosphorylation of its substrates, MYPT1 and MLC. In both GK rat and in human type 2 diabetic retinas, ROCK-1 is activated and associated with non-apoptotic membrane blebbing in retinal vessels and in retinal pigment epithelium (RPE) that respectively form the inner and the outer barriers. Activation of ROCK-1 induces focal vascular constrictions, endoluminal blebbing and subsequent retinal hypoxia. In RPE cells, actin cytoskeleton remodeling and membrane blebs in RPE cells contributes to outer barrier breakdown. Intraocular injection of fasudil, significantly reduces both retinal hypoxia and RPE barrier breakdown. Diabetes-induced cell blebbing may contribute to ischemic maculopathy and represent an intervention target.

  13. PROPERTIES TYRE TREAD RUBBERS DEPENDING ON PARTICULARITY OF RUBBER COMPOUND

    Directory of Open Access Journals (Sweden)

    Z. S. Shashok

    2014-01-01

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

  14. Predictive value of early postoperative IOP and bleb morphology in Mitomycin-C augmented trabeculectomy [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Hamed Esfandiari

    2017-12-01

    Full Text Available Background: To determine the predictive value of postoperative bleb morphological features and intraocular pressure (IOP on the success rate of trabeculectomy. Methods: In this prospective interventional case series, we analyzed for one year 80 consecutive primary open angle glaucoma patients who underwent mitomycin-augmented trabeculectomy. Bleb morphology was scored using the Indiana bleb appearance grading scale (IBAGS. Success was defined as IOP ≤15 mmHg at 12 months. We applied a multivariable regression analysis and determined the area under the receiver operating characteristic curve (AUC. Results: The mean age of participants was 62±12.3 years in the success and 63.2±16.3 years in the failure group (P= 0.430 with equal gender distribution (P=0.911. IOPs on day 1, 7 and 30 were similar in both (P= 0.193, 0.639, and 0.238, respectively. The AUC of IOP at day 1, day 7 and 30 for predicting a successful outcome was 0.355, 0.452, and 0.80, respectively. The AUC for bleb morphology parameters of bleb height, extension, and vascularization, on day 14 were 0.368, 0.408, and 0.549, respectively. Values for day 30 were 0.428, 0.563, and 0.654. IOP change from day 1 to day 30 was a good predictor of failure (AUC=0.838, 95% CI: 0.704 to 0.971 with a change of more than 3 mmHg predicting failure with a sensitivity of 82.5% (95% CI: 68 to 91% and a specificity of 87.5% (95% CI: 53 to 98%. Conclusions: IOP on day 30 had a fair to good accuracy while bleb features failed to predict success except bleb vascularity that had a poor to fair accuracy.  An IOP increase more than 3 mmHg during the first 30 days was a good predictor of failure.

  15. Quarter-Shifted Microincisional Sutureless Vitrectomy in Patients with a Glaucoma Drainage Implant or Filtering Bleb.

    Science.gov (United States)

    Song, Ji Hun; Jang, Seran; Cho, Eun Hyung; Ahn, Jaehong

    2017-05-01

    When vitrectomy is performed in eyes that have undergone glaucoma surgery, the site of sclerotomy often overlaps with the previous glaucoma operation site. It can lead to serious complications such as postoperative hypotony, leakage, and/or infection. Our technique involves modification of surgeon's position and two sclerotomy sites 45° away from the original position, with an infusion cannula inserted infranasally to avoid damage to the glaucoma drainage implant or filtering bleb. The modified approach was applied to seven eyes with various indications. Vitrectomy was successfully completed, and there were no sclerotomy site complications, leakage, or hypotony in any case. Good intraocular pressure control was maintained throughout the postoperative course in all cases. © Copyright: Yonsei University College of Medicine 2017.

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    Andrea Hillebrand

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

  18. Robotically enhanced rubber hand illusion.

    Science.gov (United States)

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

    2014-01-01

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

  19. 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.

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

    NARCIS (Netherlands)

    Sarkawi, S.S.

    2013-01-01

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

  1. Solubility Study of Curatives in Various Rubbers

    NARCIS (Netherlands)

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

    2008-01-01

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

  2. Ab Interno Trabeculectomy With the Trabectome as a Valuable Therapeutic Option for Failed Filtering Blebs.

    Science.gov (United States)

    Wecker, Thomas; Neuburger, Matthias; Bryniok, Laura; Bruder, Kathrin; Luebke, Jan; Anton, Alexandra; Jordan, Jens F

    2016-09-01

    Uncontrolled intraocular pressure (IOP) after glaucoma filtration surgery is a challenging problem in the management of glaucoma patients. The Trabectome is a device for selective electroablation of the trabecular meshwork through a clear cornea incision without affecting the conjunctiva. Minimally invasive glaucoma surgery using the Trabectome is safe and effective as primary glaucoma surgery. Here we investigate the results of ab interno trabeculectomy with the Trabectome for IOP control in patients with a failed filtering bleb. A total of 60 eyes of 60 consecutive patients with primary open-angle glaucoma (POAG) or pseudoexfoliative glaucoma (PXG) were enrolled in this single center observational study. Trabectome surgery was performed alone or in combination with phacoemulsification by 2 experienced surgeons. IOP readings and number of IOP lowering medication as primary outcome parameters were taken by an independent examiner. Intraoperative and postoperative medication were recorded systematically. Mean IOP before surgery was 24.5±3.5 mm Hg and decreased to 15.7±3.4 (-36%) after mean follow-up of 415 days. The number of necessary IOP lowering medication dropped from 2.1±1.3 to 1.8±1.2 (14% reduction from baseline). A total of 25% (n=15) of cases reported here needed additional surgery after 517 days (range: 6 to 1563 d). No major complications were observed. After mean follow-up, we found a qualified success rate for PXG of 87% and 50% for POAG as revealed by the Kaplan-Meier analysis according to the definitions for success in advanced glaucoma cases according to the World Glaucoma Association (40% reduction from baseline IOP and maximum IOP of 15 mm Hg). Trabectome surgery for uncontrolled IOP after trabeculectomy is safe and effective especially in PXG patients. Given the demanding subgroup of patients studied here, it is not surprising that success rates are lower compared with previous studies investigating the Trabectome for primary glaucoma surgery

  3. The Cyclization of natural rubber

    International Nuclear Information System (INIS)

    Mirzataheri, M.

    2000-01-01

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

  4. Lignocellulosic fiber reinforced rubber composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available polymerization reaction using Zieglar-Natta- hetergenous catalyst. The important components of NR are given in Table I. Lignocellulosic Fiber Reinforced Rubber Composites -253- Figure 1. Structure of natural rubber NR has a very uniform.... Grafting a second polymer onto the NR backbone Grafting is mostly carried out using vinyl monomers like methyl methacrylate (MMA) and styrene. The commercial available grafted copolymer of NR with poly (methyl methacrylate) (PMMA) is Heveaplus MG...

  5. 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.

  6. 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...

  7. Conservative treatment for late-onset bleb leaks after trabeculectomy with mitomycin C in patients with ocular surface disease

    Directory of Open Access Journals (Sweden)

    Sagara H

    2012-08-01

    Full Text Available Hideto Sagara,1,2 Tomohiro Iida,2,3 Kimimori Saito,4 Hiroki Noji,2 Masashi Ogasawara,2 Hiroshi Oyamada21The Marui Eye Clinic, Fukushima, 2Department of Ophthalmology, Fukushima Medical University School of Medicine, Fukushima, 3Tokyo Women's Medical University, Tokyo, 4Matuki Eye Clinic, Fukushima, JapanBackground: Sodium hyaluronate and autologous serum eye drops are used to treat ocular surface disease (OSD and are reported to prevent and treat late-onset bleb leaks following trabeculectomy with mitomycin C. In this study, we evaluated the efficacy of a combination of sodium hyaluronate and autologous serum eye drops and treatment for obstructive meibomian gland dysfunction as a therapy for late-onset bleb leaks after trabeculectomy with mitomycin C.Methods: This was a retrospective, interventional, nonsimultaneous study of 12 subjects (12 eyes of mean age of 64.3 ± 18.3 years with OSD and apparent late-onset bleb leaks following trabeculectomy with mitomycin C between 1998 and 2008. We compared patients diagnosed with leakages before July 2005, who had been treated with separate eye drop solutions containing 0.1% sodium hyaluronate, 50% autologous serum, and 0.3% ofloxacin (sodium hyaluronate and autologous serum group, n = 7, with patients diagnosed from August 2005 to December 2008, who were treated with a combination of eye drops (0.1% sodium hyaluronate, 50% autologous serum, and 0.08% levofloxacin hydrate and eyelid massage and warm compresses for obstructive meibomian gland dysfunction (combination eye drop group, n = 5.Results: Leakage was resolved in one patient (14.3% in the separately treated sodium hyaluronate and autologous serum eye drop group and in five patients (100% in the combination eye drop group (P = 0.015. The period after resolution of leakage with conservative treatment was 23 months in the one eye in the sodium hyaluronate and autologous serum group and 36–61 (mean 52.4 ± 10.1 months in the five eyes in the

  8. Replacement value of rubber seed ( Hevea brasiliensis ) meal for ...

    African Journals Online (AJOL)

    Rubber seed meal (RSM) contains about 28.63% CP but also high in CF (20%). Rubber seed cake was extruded after the extraction of rubber seed oil from the Rubber Seed oil processing Department of Rubber Research Institute of Nigeria, Benin-City. The rubber seed cake was then milled to produce RSM. Soya bean ...

  9. 75 FR 57980 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-09-23

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

  10. Nylon fabric reinforced natural rubber compound

    Science.gov (United States)

    Kamal, Mazlina Mustafa; Ismail, Ismaliza

    2017-12-01

    Rubber fabric coated is a unique rubber-textile composite, in which technical textile acts as reinforcing material and strength providing material. In rubber textile composite, rubber to fabric adhesion plays the most critical role for determining assembly process and ultimate strength of product. A vulcanisable adhesive for rubber to fabric fabrication of composite material was developed which compatible with rubber as well as fabric. Evaluation of bonding system with respect to peel strength, shear adhesion strength and weave pattern of fabrics were the major determining criteria for selection and optimization of fabric for rubber hose application. Thus adhesive Cohedure with characteristics of high adhesive strength in Natural Rubber Polyester Fabric compound has been developed.

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

    African Journals Online (AJOL)

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

  12. Electrospinning of PVC with natural rubber

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-27

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

  13. Modeling the Excess Cell Surface Stored in a Complex Morphology of Bleb-Like Protrusions.

    Directory of Open Access Journals (Sweden)

    Maryna Kapustina

    2016-03-01

    Full Text Available Cells transition from spread to rounded morphologies in diverse physiological contexts including mitosis and mesenchymal-to-amoeboid transitions. When these drastic shape changes occur rapidly, cell volume and surface area are approximately conserved. Consequently, the rounded cells are suddenly presented with a several-fold excess of cell surface whose area far exceeds that of a smooth sphere enclosing the cell volume. This excess is stored in a population of bleb-like protrusions (BLiPs, whose size distribution is shown by electron micrographs to be skewed. We introduce three complementary models of rounded cell morphologies with a prescribed excess surface area. A 2D Hamiltonian model provides a mechanistic description of how discrete attachment points between the cell surface and cortex together with surface bending energy can generate a morphology that satisfies a prescribed excess area and BLiP number density. A 3D random seed-and-growth model simulates efficient packing of BLiPs over a primary rounded shape, demonstrating a pathway for skewed BLiP size distributions that recapitulate 3D morphologies. Finally, a phase field model (2D and 3D posits energy-based constitutive laws for the cell membrane, nematic F-actin cortex, interior cytosol, and external aqueous medium. The cell surface is equipped with a spontaneous curvature function, a proxy for the cell surface-cortex couple, that is a priori unknown, which the model "learns" from the thin section transmission electron micrograph image (2D or the "seed and growth" model image (3D. Converged phase field simulations predict self-consistent amplitudes and spatial localization of pressure and stress throughout the cell for any posited stationary morphology target and cell compartment constitutive properties. The models form a general framework for future studies of cell morphological dynamics in a variety of biological contexts.

  14. 75 FR 38119 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-07-01

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

  15. 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.

  16. Blunt needle revision with viscoelastic materials via the anterior chamber for early failed filtering blebs after trabeculectomy

    Directory of Open Access Journals (Sweden)

    Yamagami H

    2012-06-01

    Full Text Available Nozomi Kinoshita, Ayumi Ota, Fumihiko Toyoda, Hiroko Yamagami, Akihiro KakehashiDepartment of Ophthalmology, Saitama Medical Center, Jichi Medical University, Saitama, JapanPurpose: To report a new technique of blunt needle revision with viscoelastic materials via the anterior chamber for the treatment of early failed filtering blebs and elevated intraocular pressure after trabeculectomy, in which digital ocular massage and laser suture lysis have been ineffective.Methods: A 27-gauge blunt needle attached to a syringe containing viscoelastic material was inserted into the anterior chamber from the inferior paracentesis. The needle tip was inserted into the subscleral flap space from the filtering fistula at the anterior chamber side, and the scleral flap was lifted bluntly. The needle tip was then inserted into the subconjunctival space where the viscoelastic agent was injected and the adhesion between the sclera and conjunctiva was separated bluntly. Blunt needle revision via the anterior chamber was performed 14 times in six eyes of six patients at Saitama Medical Center, Jichi Medical University from January 2007 to May 2009. All procedures were performed within 1 month after trabeculectomy.Results: The intraocular pressure remained 21 mmHg or lower for more than 6 months in three of six eyes. Slight bleeding from the iris occurred in one of the 14 procedures, and hypotony (intraocular pressure below 5 mmHg occurred in one of the 14 procedures. No serious complications developed.Conclusion: Blunt needle revision via the anterior chamber for early failed filtering blebs is a new, simple, and safe procedure.Keywords: glaucoma, trabeculectomy, filtering bleb, needle revision, blunt needle

  17. Cryogenic Deflashing for Rubber Products

    Directory of Open Access Journals (Sweden)

    Abhilash M.

    2018-01-01

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

  18. [Anaphylaxis to blue dyes].

    Science.gov (United States)

    Langner-Viviani, F; Chappuis, S; Bergmann, M M; Ribi, C

    2014-04-16

    In medicine, vital blue dyes are mainly used for the evaluation of sentinel lymph nodes in oncologic surgery. Perioperative anaphylaxis to blue dyes is a rare but significant complication. Allergic reactions to blue dyes are supposedly IgE-mediated and mainly caused by triarylmethanes (patent blue and isosulfane blue) and less frequently by methylene blue. These substances usually do not feature on the anesthesia record and should not be omitted from the list of suspects having caused the perioperative reaction, in the same manner as latex and chlorhexidine. The diagnosis of hypersensitivity to vital blue dyes can be established by skin test. We illustrate this topic with three clinical cases.

  19. Prehistoric polymers: rubber processing in ancient mesoamerica

    Science.gov (United States)

    Hosler; Burkett; Tarkanian

    1999-06-18

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

  20. Constructing better roads with asphalt rubber

    Directory of Open Access Journals (Sweden)

    Pais Jorge C.

    2015-12-01

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

  1. Radiation cured silicone rubber articles

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  2. 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.

  3. Thermal endurance tests on silicone rubber specimens

    International Nuclear Information System (INIS)

    Warburton, C.

    1977-07-01

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

  4. Statistical distribution analysis of rubber fatigue data

    Science.gov (United States)

    DeRudder, J. L.

    1981-10-01

    Average rubber fatigue resistance has previously been related to such factors as elastomer type, cure system, cure temperature, and stress history. This paper extends this treatment to a full statistical analysis of rubber fatigue data. Analyses of laboratory fatigue data are used to predict service life. Particular emphasis is given to the prediction of early tire splice failures, and to adaptations of statistical fatigue analysis for the particular service conditions of the rubber industry.

  5. Brittle-tough transition in nylon-rubber blends: effect of rubber concentration and particle size

    NARCIS (Netherlands)

    Borggreve, R.J.M.; Gaymans, R.J.; Schuijer, J.; Ingen Housz, J.F.

    1987-01-01

    Blends of nylon-6 and EPDM-rubber were prepared with various rubber contents (0–20 wt%) and particle sizes (0.3–1.6 μm). The effects of rubber concentration and particle size on the tensile modulus, torsion modulus, yield stress and notched impact strength of the blends were studied. Blend

  6. 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

    Dynamic regulation of the actin-cytoskeleton is essential to cell motility, spreading, and the formation of membrane surface extensions like lamellipodia, ruffles and blebs. The ubiquitous calpains contribute to integrin-mediated cytoskeletal remodelling during cell migration and spreading, by cl...

  7. 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.

  8. 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.

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

    OpenAIRE

    Nasruddin, Nasruddin

    2017-01-01

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

  10. Blue-Green Algae

    Science.gov (United States)

    ... people with hepatitis C or hepatitis B. HIV/AIDS. Research on the effects of blue-green algae in people with HIV/AIDS has been inconsistent. Some early research shows that taking 5 grams of blue-green ...

  11. EPDM rubber reclaim from devulcanized EPDM

    NARCIS (Netherlands)

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

    2006-01-01

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

  12. Why Does a Rubber Ball Bounce? -48 ...

    Indian Academy of Sciences (India)

    Rubber and rubber-like materials are fascinating because they exhibit a unique combination of two characteristics, (a) they can sustain very high elongation without rupture (5-10 times their original length is fairly common) and (b) spontaneous recovery to essentially their original state, with little or no permanent deformation ...

  13. Biorefinery of proteins from rubber plantation residues

    NARCIS (Netherlands)

    Widyarani, R.

    2016-01-01

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

  14. Unraveling the Mystery of Natural Rubber Biosynthesis

    Science.gov (United States)

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

  15. Natural rubber producing plants: An overview

    African Journals Online (AJOL)

    User

    2013-03-20

    Mar 20, 2013 ... rubber tree, are known to produce large amounts of rubber with high molecular weight: a shrub named .... applications. DISTRIBUTION. H. brasiliensis was introduced to tropical Asia in 1876 through Kew garden from the seeds brought from Rio. Tapajo'z ...... However, there is very little molecular data.

  16. Photoinduced orientation in natural rubber

    Science.gov (United States)

    de Souza, Nara C.; Cavalheri, Adriana S.; Brito, Jackeline B.; Job, Aldo E.; Oliveira, Osvaldo N.; Giacometti, José A.; Silva, Josmary R.

    2012-04-01

    Azobenzene molecules and their derivatives have been widely investigated for their potential applications in optical and electrooptical devices. We have prepared a new guest-host system from natural rubber (NR) impregnated with azobenzene derivative Sudan Red B (SRB). The effects of stretching and immersion time on photoinduced orientation were investigated by birefringence signal measurements. We have found that the molecular orientation increase when the samples are stretched and decrease with the increase of immersion time. The first behavior was explained by using the random coil model and the latter was attributed to increase of the aggregation of SRB into NR matrix.

  17. Estimation of genetic parameters in rubber progenies

    Directory of Open Access Journals (Sweden)

    Cecília Khusala Verardi

    2012-09-01

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

  18. Coal Producer's Rubber Waste Processing Development

    Science.gov (United States)

    Makarevich, Evgeniya; Papin, Andrey; Nevedrov, Alexander; Cherkasova, Tatyana; Ignatova, Alla

    2017-11-01

    A large amount of rubber-containing waste, the bulk of which are worn automobile tires and conveyor belts, is produced at coal mining and coal processing enterprises using automobile tires, conveyor belts, etc. The volume of waste generated increases every year and reaches enormous proportions. The methods for processing rubber waste can be divided into three categories: grinding, pyrolysis (high and low temperature), and decomposition by means of chemical solvents. One of the known techniques of processing the worn-out tires is their regeneration, aimed at producing the new rubber substitute used in the production of rubber goods. However, the number of worn tires used for the production of regenerate does not exceed 20% of their total quantity. The new method for processing rubber waste through the pyrolysis process is considered in this article. Experimental data on the upgrading of the carbon residue of pyrolysis by the methods of heavy media separation, magnetic and vibroseparation, and thermal processing are presented.

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

    Directory of Open Access Journals (Sweden)

    Abu Hasan

    2013-04-01

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

  20. Treatment of wastewater from rubber industry in Malaysia ...

    African Journals Online (AJOL)

    Presently, Malaysia is the third largest rubber producer in the world, whereby the rubber industry is an economically and socially significant industry. Rubber industry consumes large volumes of water, uses chemicals and other utilities and produces enormous amounts of wastes and effluent. Discharge of untreated rubber ...

  1. 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.

  2. Cream concentrated latex for foam rubber products

    Science.gov (United States)

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

    2017-12-01

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

  3. Performance of self-compacting rubberized concrete

    Directory of Open Access Journals (Sweden)

    Hamza Bensaci

    2018-01-01

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

  4. Parameters for the analysis of natural rubber drying

    OpenAIRE

    Sangwichien, C.; Tirawanicahkul, Y.; Tirawanichakul, S.; Sanai, S.

    2007-01-01

    The purpose of this research was to study and develop a mathematical model of essential parameters affecting drying process in terms of equilibrium moisture content (EMC), apparent density, percentage ofvoid fraction, specific heat capacity and effective diffusion coefficient (D) for three kinds of natural rubber. Three raw natural rubber samples in this work used crumb rubber, rubber stick and rubber sheet with aninitial moisture content ranging between 30 and 45% wet-basis that were normall...

  5. Fatigue life of automotive rubber jounce bumper

    International Nuclear Information System (INIS)

    Sidhu, R S; Ali, Aidy

    2010-01-01

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

  6. 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.

  7. Construction of Pará rubber tree genome and multi-transcriptome database accelerates rubber researches.

    Science.gov (United States)

    Makita, Yuko; Kawashima, Mika; Lau, Nyok Sean; Othman, Ahmad Sofiman; Matsui, Minami

    2018-01-19

    Natural rubber is an economically important material. Currently the Pará rubber tree, Hevea brasiliensis is the main commercial source. Little is known about rubber biosynthesis at the molecular level. Next-generation sequencing (NGS) technologies brought draft genomes of three rubber cultivars and a variety of RNA sequencing (RNA-seq) data. However, no current genome or transcriptome databases (DB) are organized by gene. A gene-oriented database is a valuable support for rubber research. Based on our original draft genome sequence of H. brasiliensis RRIM600, we constructed a rubber tree genome and transcriptome DB. Our DB provides genome information including gene functional annotations and multi-transcriptome data of RNA-seq, full-length cDNAs including PacBio Isoform sequencing (Iso-Seq), ESTs and genome wide transcription start sites (TSSs) derived from CAGE technology. Using our original and publically available RNA-seq data, we calculated co-expressed genes for identifying functionally related gene sets and/or genes regulated by the same transcription factor (TF). Users can access multi-transcriptome data through both a gene-oriented web page and a genome browser. For the gene searching system, we provide keyword search, sequence homology search and gene expression search; users can also select their expression threshold easily. The rubber genome and transcriptome DB provides rubber tree genome sequence and multi-transcriptomics data. This DB is useful for comprehensive understanding of the rubber transcriptome. This will assist both industrial and academic researchers for rubber and economically important close relatives such as R. communis, M. esculenta and J. curcas. The Rubber Transcriptome DB release 2017.03 is accessible at http://matsui-lab.riken.jp/rubber/ .

  8. Evaluation of crumb rubber as aggregate for automated manufacturing of rubberized long hollow blocks and bricks

    OpenAIRE

    Sodupe-Ortega, E.; Fraile-Garcia, E.; Ferreiro-Cabello, J.; Sanz-Garcia, A.

    2016-01-01

    Waste tire rubber is a promising lightweight aggregate for building products that enhances their thermal and acoustic properties. Even the environmental benefits of its use are evident, higher cost and significant changes in compressive strength and workability hinder its widespread adoption. This article examines the use of crumb rubber (CR) as aggregate in dry-mix mortars to produce rubberized long hollow blocks and bricks using automated brick machines. CR was incorporated over a range of ...

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

    OpenAIRE

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

    2016-01-01

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

  10. Expression of Tau Produces Aberrant Plasma Membrane Blebbing in Glial Cells Through RhoA-ROCK-Dependent F-Actin Remodeling.

    Science.gov (United States)

    Torres-Cruz, Francisco M; Rodríguez-Cruz, Fanny; Escobar-Herrera, Jaime; Barragán-Andrade, Norma; Basurto-Islas, Gustavo; Ripova, Daniela; Ávila, Jesús; Garcia-Sierra, Francisco

    2016-03-21

    Abnormal aggregation of Tau in glial cells has been reported in Alzheimer's disease (AD) and other tauopathies; however, the pathological significance of these aggregates remains unsolved to date. In this study, we evaluated whether full-length Tau (Tau441) and its aspartic acid421-truncated Tau variant (Tau421) produce alterations in the normal organization of the cytoskeleton and plasma membrane (PM) when transiently expressed in cultured C6-glial cells. Forty-eight hours post-transfection, abnormal microtubule bundling was observed in the majority of the cells, which expressed either Tau441 or Tau421. Moreover, both variants of Tau produced extensive PM blebbing associated with cortical redistribution of filamentous actin (F-Actin). These effects were reverted when Tau-expressing cells were incubated with drugs that depolymerize F-Actin. In addition, when glial cells showing Tau-induced PM blebbing were incubated with inhibitors of the Rho-associated protein kinase (ROCK) signaling pathway, both formation of abnormal PM blebs and F-Actin remodeling were avoided. All of these effects were initiated upstream by abnormal Tau-induced microtubule bundling, which may release the microtubule-bound guanine nucleotide exchange factor-H1 (GEF-H1) into the cytoplasm in order to activate its major effector RhoA-GTPase. These results may represent a new mechanism of Tau toxicity in which Tau-induced microtubule bundling produces activation of the Rho-GTPase-ROCK pathway that in turn mediates the remodeling of cortical Actin and PM blebbing. In AD and other tauopathies, these Tau-induced abnormalities may occur and contribute to the impairment of glial activity.

  11. Oils and rubber from arid land plants

    Science.gov (United States)

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

    1980-05-01

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

  12. Radiation stability of plastics and rubbers

    International Nuclear Information System (INIS)

    Hitchon, J.W.

    1983-01-01

    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.)

  13. Plastics and Rubber Products Manufacturing (NAICS 326)

    Science.gov (United States)

    Find environmental regulatory and compliance information for plastics and rubber products manufacturing (which includes the manufacture of cellulose and other fibers) including information about NESHAPs and effluent guidelines for wastewater discharges

  14. Contact allergy to rubber accelerators remains prevalent

    DEFF Research Database (Denmark)

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

    2016-01-01

    INTRODUCTION: Chemicals used for the manufacturing of rubber are known causes of allergic contact dermatitis on the hands. Recent European studies have suggested a decrease in thiuram contact allergy. Moreover, while an association with hand dermatitis is well established, we have recently observed...... several clinical cases with allergic facial dermatitis to rubber. OBJECTIVES: To evaluate temporal trends of contact allergy to rubber accelerators from the European baseline series in a tertiary patch test clinic in Denmark, and examine associations with anatomical locations of dermatitis. METHODS: Patch.......0%, mercaptobenzothiazole 2.0% and mercapto mix 1.0%. RESULTS: The overall prevalence of contact allergy to rubber accelerators was 3.1% with no significant change during the study period (Ptrend = 0.667). Contact allergy to thiuram mix was the most prevalent and was significantly associated with occupational contact...

  15. 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.

  16. Melanosome transfer to keratinocyte in the chicken embryonic skin is mediated by vesicle release associated with Rho-regulated membrane blebbing.

    Science.gov (United States)

    Tadokoro, Ryosuke; Murai, Hidetaka; Sakai, Ken-Ichiro; Okui, Takahiro; Yokota, Yasuhiro; Takahashi, Yoshiko

    2016-12-02

    During skin pigmentation in amniotes, melanin synthesized in the melanocyte is transferred to keratinocytes by a particle called the melanosome. Previous studies, mostly using dissociated cultured cells, have proposed several different models that explain how the melanosome transfer is achieved. Here, using a technique that labels the plasma membrane of melanocytes within a three-dimensional system that mimics natural tissues, we have visualized the plasma membrane of melanocytes with EGFP in chicken embryonic skin. Confocal time-lapse microscopy reveals that the melanosome transfer is mediated, at least in part, by vesicles produced by plasma membrane. Unexpectedly, the vesicle release is accompanied by the membrane blebbing of melanocytes. Blebs that have encapsulated a melanosome are pinched off to become vesicles, and these melanosome-containing vesicles are finally engulfed by neighboring keratinocytes. For both the membrane blebbing and vesicle release, Rho small GTPase is essential. We further show that the membrane vesicle-mediated melanosome transfer plays a significant role in the skin pigmentation. Given that the skin pigmentation in inter-feather spaces in chickens is similar to that in inter-hair spaces of humans, our findings should have important consequences in cosmetic medicine.

  17. Mutations in ASPH cause facial dysmorphism, lens dislocation, anterior-segment abnormalities, and spontaneous filtering blebs, or Traboulsi syndrome.

    Science.gov (United States)

    Patel, Nisha; Khan, Arif O; Mansour, Ahmad; Mohamed, Jawahir Y; Al-Assiri, Abdullah; Haddad, Randa; Jia, Xiaofei; Xiong, Yong; Mégarbané, André; Traboulsi, Elias I; Alkuraya, Fowzan S

    2014-05-01

    We have previously described a syndrome characterized by facial dysmorphism, lens dislocation, anterior-segment abnormalities, and spontaneous filtering blebs (FDLAB, or Traboulsi syndrome). In view of the consanguineous nature of the affected families and the likely autosomal-recessive inheritance pattern of this syndrome, we undertook autozygosity mapping and whole-exome sequencing to identify ASPH as the disease locus, in which we identified two homozygous mutations. ASPH encodes aspartyl/asparaginyl β-hydroxylase (ASPH), which has been found to hydroxylate aspartic acid and asparagine residues on epidermal growth factor (EGF)-domain-containing proteins. The truncating and missense mutations we identified are predicted to severely impair the enzymatic function of ASPH, which suggests a possible link to other forms of ectopia lentis given that many of the genes implicated in this phenotype encode proteins that harbor EGF domains. Developmental analysis of Asph revealed an expression pattern consistent with the proposed link to the human syndrome. Indeed, Asph-knockout mice had a foreshortened snout, which corresponds to the facial abnormalities in individuals with Traboulsi syndrome. These data support a genetic basis for a syndromic form of ectopia lentis and the role of aspartyl hydroxylation in human development. Copyright © 2014 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  18. Compressive modulus of adhesive bonded rubber block

    OpenAIRE

    Wiriya Thongruang; Charoenyut Dechwayukul

    2008-01-01

    The present study examined the effect of a thin adhesive layer on the modulus of an elastic rubber block bonded between two plates. The plates were assumed to be rigid, both in extension and flexure, and subjected to vertical compression loading. The Gent’s approach was used to obtain the analytic deformations of the rubber and adhesive. The analytic deformations were then validated with the finite element model. There was a good agreement between both methods. The modulus of the bonded rubbe...

  19. Blue Ocean Thinking

    Science.gov (United States)

    Orem, Donna

    2016-01-01

    This article describes a concept called the "blue ocean thinking strategy," developed by W. Chan Kim and Renée Mauborgne, professors at INSEAD, an international graduate school of business in France. The "blue ocean" thinking strategy considers opportunities to create new markets for services, rather than focusing solely on…

  20. Aspects of silicone rubber as encapsulant for neurological prostheses. Part 4: Two-part rubbers.

    Science.gov (United States)

    Donaldson, P E

    1997-05-01

    The durability of the adhesion, in the presence of water, of three two-part silicone rubbers to five adherends of practical interest is examined. The results are contrasted with those obtained, in previous work, from single-part material. It is concluded that two-part rubbers promise outstanding performance in particular circumstances.

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

    NARCIS (Netherlands)

    Deladi, E.L.

    2006-01-01

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

  2. Silica-reinforced natural rubber: use of natural rubber grafted with chemical functionalities as compatibilizer

    NARCIS (Netherlands)

    Sengloyluan, K.

    2015-01-01

    Epoxidized natural rubber (ENR) is a modified form of NR bearing polar epoxy groups. This work investigates a silica-reinforced NR tire tread compounds with ENR as a compatibilizer. The ENRs consisting of 10, 38 and 51 mol% epoxide are used in a range of 2.5 to 15.0 parts per hundred parts of rubber

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

    NARCIS (Netherlands)

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

    2017-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Maryam Mansourirad

    2014-12-01

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

  5. 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.

  6. Parameters for the analysis of natural rubber drying

    Directory of Open Access Journals (Sweden)

    Sangwichien, C.

    2007-05-01

    Full Text Available The purpose of this research was to study and develop a mathematical model of essential parameters affecting drying process in terms of equilibrium moisture content (EMC, apparent density, percentage ofvoid fraction, specific heat capacity and effective diffusion coefficient (D for three kinds of natural rubber. Three raw natural rubber samples in this work used crumb rubber, rubber stick and rubber sheet with aninitial moisture content ranging between 30 and 45% wet-basis that were normally used for producing the standardized Thai rubber (STR block rubber and air dried rubber sheet (ADS. The results show that theapparent density and specific heat of all natural rubber samples were linearly dependent on the moisture content whilst the percentage of void fraction of natural rubber was inversely related to moisture content.The isotherm EMC equations formulated by the Herderson model for the crumb rubber and rubber stick were the best fitting with the experimental values, and for the rubber sheet. The isotherm EMC equationusing the Halsey model was the most appropriable to the experimental results. In addition, the effective diffusion coefficients of all natural rubber materials, which were the function of drying temperature and drying time, were in range of 10-6-10-7 m2/hr. However, prediction of the evolution of moisture content ofthin-layer drying under the condition of drying temperatures of 40-70oC (rubber stick and rubber sheet and 100-130oC (crumb rubber could be explained by the empirical model, which was the function of drying temperature and drying time.

  7. Thermodynamically stable blue phases.

    Science.gov (United States)

    Castles, F; Morris, S M; Terentjev, E M; Coles, H J

    2010-04-16

    We show theoretically that flexoelectricity stabilizes blue phases in chiral liquid crystals. Induced internal polarization reduces the elastic energy cost of splay and bend deformations surrounding singular lines in the director field. The energy of regions of double twist is unchanged. This in turn reduces the free energy of the blue phase with respect to that of the chiral nematic phase, leading to stability over a wider temperature range. The theory explains the discovery of large temperature range blue phases in highly flexoelectric "bimesogenic" and "bent-core" materials, and predicts how this range may be increased further.

  8. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1991-01-01

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

  9. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1989-01-01

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

  10. Compressive modulus of adhesive bonded rubber block

    Directory of Open Access Journals (Sweden)

    Wiriya Thongruang

    2008-03-01

    Full Text Available The present study examined the effect of a thin adhesive layer on the modulus of an elastic rubber block bonded between two plates. The plates were assumed to be rigid, both in extension and flexure, and subjected to vertical compression loading. The Gent’s approach was used to obtain the analytic deformations of the rubber and adhesive. The analytic deformations were then validated with the finite element model. There was a good agreement between both methods. The modulus of the bonded rubber block, defined as effective modulus, was then studied. The effective modulus was increased by the factor (1+ (a/2t2(6Grh/Gat+1-1, which is composed of the shape factor of the rubber block (a/2t, ratio of the bonded and unbonded areas, and the shear stiffness factor (Grh/Gat, ratio of modulus and thickness of rubber and adhesive. The effective modulus does not depend on either factors, when the shear stiffness of the joint is high or Grh/Gat >10.

  11. Blue Ribbon Panel Report

    Science.gov (United States)

    An NCI Cancer Currents blog by the NCI acting director thanking the cancer community for contributing to the Cancer Moonshot Blue Ribbon Panel report, which was presented to the National Cancer Advisory Board on September 7.

  12. 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...

  13. 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.

  14. Development of rubber gloves by radiation vulcanization

    International Nuclear Information System (INIS)

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

    1990-01-01

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

  15. Coatings for rubber bonding and paint adhesion

    Science.gov (United States)

    Boulos, M. S.; Petschel, M.

    1997-08-01

    Conversion coatings form an important base for the adhesion of paint to metal substrates and for the bonding of rubber to metal parts. Four types of conversion coatings were assessed as base treatments for the bonding of rubber to steel and for the corrosion protection of metal substrates under paint: amorphous iron phosphate, heavy zinc phosphate, and three types of modified zinc phosphates that utilized one or more metal cations in addition to zinc. When applied, these conversion coatings formed a thin film over the metal substrate that was characterized by scanning electron microscopy, x-ray diffraction, and chemical methods. The performance of the coatings was assessed using physical methods such as dry adhesion, conical mandrel, impact, and stress adhesion for the rubber-bonded parts, and by corrosion resistance methods such as humidity, salt spray, and cyclic corrosion. Coating characterization and performance were correlated.

  16. Mechanical Properties of Graphene-Rubber Nanocomposites

    Science.gov (United States)

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

    2017-11-01

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

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  18. 30 CFR 77.606-1 - Rubber gloves; minimum requirements.

    Science.gov (United States)

    2010-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Glaucio Laun Nacif

    2013-04-01

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

  20. 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

  1. minimum variance estimation of yield parameters of rubber tree

    African Journals Online (AJOL)

    2013-03-01

    Mar 1, 2013 ... year. Kalman filter, a flexible statistical estimator, is used to combine the inexact prediction of the rubber production with an equally inexact rubber yield, tree ... tapping system measurements to obtain an optimal estimate of one year ahead rubber production. ...... tation management prevision gap of 55%.

  2. Modified Silicone-Rubber Tooling For Molding Composite Parts

    Science.gov (United States)

    Baucom, Robert M.; Snoha, John J.; Weiser, Erik S.

    1995-01-01

    Reduced-thermal-expansion, reduced-bulk-modulus silicone rubber for use in mold tooling made by incorporating silica powder into silicone rubber. Pressure exerted by thermal expansion reduced even further by allowing air bubbles to remain in silicone rubber instead of deaerating it. Bubbles reduce bulk modulus of material.

  3. Thermoreversibly Cross-Linked EPM Rubber Nanocomposites with Carbon Nanotubes

    NARCIS (Netherlands)

    Polgar, Lorenzo Massimo; Criscitiello, Francesco; van Essen, Machiel; Araya-Hermosilla, Rodrigo; Migliore, Nicola; Lenti, Mattia; Raffa, Patrizio; Picchioni, Francesco; Pucci, Andrea

    2018-01-01

    Conductive rubber nanocomposites were prepared by dispersing conductive nanotubes (CNT) in thermoreversibly cross-linked ethylene propylene rubbers grafted with furan groups (EPM-g-furan) rubbers. Their features were studied with a strong focus on conductive and mechanical properties relevant for

  4. Color Spectrum Properties of Pure and Non-Pure LATEX in Discriminating Rubber Clone Series

    International Nuclear Information System (INIS)

    Noor Aishah Khairuzzaman; Hadzli Hashim; Nina Korlina Madzhi; Noor Ezan Abdullah; Faridatul Aima Ismail; Ahmad Faiz Sampian; Azhana Fatnin Che Will

    2015-01-01

    A study of color spectrum properties for pure and non-pure latex in discriminating rubber clone series has been presented in this paper. There were five types of clones from the same series being used as samples in this study named RRIM2002, RRIM2007, RRIM2008, RRIM2014, and RRIM3001. The main objective is to identify the significant color spectrum (RGB) from pure and non-pure latex that can discriminate rubber clone series. The significant information of color spectrum properties for pure and non-pure latex is determined by using spectrometer and Statistical Package for the Social Science (SPSS). Visible light spectrum (VIS) is used as a radiation light of the spectrometer to emit light to the surface of the latex sample. By using SPSS software, the further numerical analysis of color spectrum properties is being conducted. As the conclusion, blue color spectrum for non-pure is able to discriminate for all rubber clone series whereas only certain color spectrum can differentiate several clone series for pure latex. (author)

  5. Fluorination of silicone rubber by plasma polymerization

    Science.gov (United States)

    Fielding, Jennifer Chase

    Plasma polymerized fluorocarbon (PPFC) films were deposited onto various silicone rubber substrates, including O-rings, to decrease oil uptake. Depositions were performed using a radio frequency (rf)-powered plasma reactor and various fluorocarbon monomers, such as C2F6, C2F 5H, C3F6, and 1H,1H,2H-perfluoro-1-dodecene. PPFC films which were most promising for inhibiting oil uptake were deposited with 1H,1H,2H-perfluoro-1-dodecene, and were composed predominantly of perfluoromethylene (CF2) species. These films displayed low critical surface energies (as low as 2.7 mJ/m2), and high contact angles with oil (84°), which were correlated with the amount of CF2 species present in the film. For the films with the highest degree of CF2 (up to 67%), CF2 chains may have been oriented slightly perpendicular to the substrate and terminated by CF3 species. Adhesion of the PPFC films directly to silicone rubber was found to be poor. However, when a plasma polymerized hydrocarbon interlayer was deposited on the silicone rubber prior to the fluorocarbon films, adhesion was excellent. O-rings coated with multilayer fluorocarbon films showed 2.6% oil uptake after soaking in oil for 100 hrs at 100°C. Due to variability in data, and the low quality of the industrial grade silicone rubber, the oil uptake mechanism was determined to be from oil flowing through flaws in the film due to defects within the substrate, not from generalized diffusion through the film. This mechanism was confirmed using higher quality silicone rubber, which showed little or no oil diffusion. Therefore, this film may perform well as an oil-repelling barrier when deposited on a high quality silicone rubber.

  6. Supply of Rubber Wood Log in Malaysia

    OpenAIRE

    Noraida, A. W.; Abdul-Rahim, A. S.

    2014-01-01

    Issue on shortage of raw material for wood processing solved by discovery of rubber wood log as one of the substitutes the natural log. This paper examines the supply of rubber wood log in Malaysia. We employ ARDL Bound Approach Test and time series data from 1980 to 2010 which represented the whole Malaysia are used to achieve the established objectives. The result shown, in the long run harvested area and wages have 1% and 10% significant level respectively. While in the short run, there wa...

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

    Directory of Open Access Journals (Sweden)

    Chamnarn Thongmark

    2016-10-01

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

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

    International Nuclear Information System (INIS)

    Samad, M S A; Ali, Aidy

    2010-01-01

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

  9. Investigation of surface halide modification of nitrile butadiene rubber

    Science.gov (United States)

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

    2017-12-01

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

  10. Analysis of Differentially Expressed Genes Associated with Coronatine-Induced Laticifer Differentiation in the Rubber Tree by Subtractive Hybridization Suppression.

    Directory of Open Access Journals (Sweden)

    Shi-Xin Zhang

    Full Text Available The secondary laticifer in the secondary phloem is differentiated from the vascular cambia of the rubber tree (Hevea brasiliensis Muell. Arg.. The number of secondary laticifers is closely related to the rubber yield potential of Hevea. Pharmacological data show that jasmonic acid and its precursor linolenic acid are effective in inducing secondary laticifer differentiation in epicormic shoots of the rubber tree. In the present study, an experimental system of coronatine-induced laticifer differentiation was developed to perform SSH identification of genes with differential expression. A total of 528 positive clones were obtained by blue-white screening, of which 248 clones came from the forward SSH library while 280 clones came from the reverse SSH library. Approximately 215 of the 248 clones and 171 of the 280 clones contained cDNA inserts by colony PCR screening. A total of 286 of the 386 ESTs were detected to be differentially expressed by reverse northern blot and sequenced. Approximately 147 unigenes with an average length of 497 bp from the forward and 109 unigenes with an average length of 514 bp from the reverse SSH libraries were assembled and annotated. The unigenes were associated with the stress/defense response, plant hormone signal transduction and structure development. It is suggested that Ca2+ signal transduction and redox seem to be involved in differentiation, while PGA and EIF are associated with the division of cambium initials for COR-induced secondary laticifer differentiation in the rubber tree.

  11. Analysis of Differentially Expressed Genes Associated with Coronatine-Induced Laticifer Differentiation in the Rubber Tree by Subtractive Hybridization Suppression.

    Science.gov (United States)

    Zhang, Shi-Xin; Wu, Shao-Hua; Chen, Yue-Yi; Tian, Wei-Min

    2015-01-01

    The secondary laticifer in the secondary phloem is differentiated from the vascular cambia of the rubber tree (Hevea brasiliensis Muell. Arg.). The number of secondary laticifers is closely related to the rubber yield potential of Hevea. Pharmacological data show that jasmonic acid and its precursor linolenic acid are effective in inducing secondary laticifer differentiation in epicormic shoots of the rubber tree. In the present study, an experimental system of coronatine-induced laticifer differentiation was developed to perform SSH identification of genes with differential expression. A total of 528 positive clones were obtained by blue-white screening, of which 248 clones came from the forward SSH library while 280 clones came from the reverse SSH library. Approximately 215 of the 248 clones and 171 of the 280 clones contained cDNA inserts by colony PCR screening. A total of 286 of the 386 ESTs were detected to be differentially expressed by reverse northern blot and sequenced. Approximately 147 unigenes with an average length of 497 bp from the forward and 109 unigenes with an average length of 514 bp from the reverse SSH libraries were assembled and annotated. The unigenes were associated with the stress/defense response, plant hormone signal transduction and structure development. It is suggested that Ca2+ signal transduction and redox seem to be involved in differentiation, while PGA and EIF are associated with the division of cambium initials for COR-induced secondary laticifer differentiation in the rubber tree.

  12. Natural Blue Food Colour

    DEFF Research Database (Denmark)

    Roda-Serrat, Maria Cinta

    In recent years, there has been a growing tendency to avoid the use of artificial colorants and additives in food products, especially after some studies linked their consumption with behavioural changes in children. However, the incorporation of colorants from natural origin remains a challenge...... for food technologists, as these are typically less vivid and less stable than their synthetic alternatives. Regarding blue colorants, phycocyanins from cyanobacteria are currently in the spotlight as promising new natural blue colorants. Phycocyanins are proteins which blue colour results from...... the presence of the chromophore phycocyanobilin (PCB), a covalently attached linear tetrapyrrole. The applications of phycocyanins as food colorants are however limited, as they show poor stability in certain conditions of pH, light and temperature. Cleavage of PCB from the protein followed by careful product...

  13. Valorisation of Proteins from Rubber Tree

    NARCIS (Netherlands)

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

    2017-01-01

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

  14. Boundary lubrication of glass: rubber sliding contacts

    NARCIS (Netherlands)

    Heide, E. van der; Lossie, C.M.; Bommel, K.J.C. van; Reinders, S.A.F.; Lenting, H.B.M.

    2009-01-01

    Polymer brush coatings represent a promising class of coatings for friction control [1], especially in a humid environment [2]. A study on the feasibility of a specific class of polymer brush coatings [5] was done for a sliding system that involves ‘silicon skin L7350’: a silicon rubber used by FIFA

  15. Wettability of silicone rubber maxillofacial prosthetic materials.

    Science.gov (United States)

    Waters, M G; Jagger, R G; Polyzois, G L

    1999-04-01

    Maxillofacial prosthetic materials that contact skin or mucosa should have good wettability. A material that is easily wetted will form a superior lubricating layer between the supporting tissues and, thus, reduce friction and patient discomfort. The surface energy of a maxillofacial prosthetic material will give an indication of the amount of energy available for adhesion and of the susceptibility of the material to bacterial adhesion. This study evaluated the wettability and surface energies of a range of commercially available silicone rubber maxillofacial prosthetic materials. Contact angles and surface energies were measured by using a dynamic contact angle measuring technique. Four commonly used silicone maxillofacial materials were tested and their properties compared with those of an acrylic resin denture base material and a widely used denture soft lining material. There were no significant differences in the wettability of the silicone rubber materials. All materials were significantly less wetted than the denture acrylic resin material. There were no significant differences in the surface energies of the silicone rubber materials, but all were significantly lower than denture acrylic resin material. The Cahn dynamic contact angle analyzer was a quick and reproducible method for determining the contact angles and surface energies of maxillofacial materials. Further work is needed to improve the wettability of silicone rubber materials used for maxillofacial prostheses, thus, reducing their potential to produce friction with tissues.

  16. Reassessment of anoxic storage of ethnographic rubber

    DEFF Research Database (Denmark)

    Dyer, Jo; Ward, Clare; Rode, Nicole

    This paper revisits the 1991–1995 British Museum field trial on anoxic storage, where 23 registered ethnographic rubber objects were enclosed in oxygen barrier film Cryovac BDF200 with sachets of the oxygen absorbent Ageless Z. A unique opportunity for study was presented since most of the enclos...

  17. Rubber Recycling: Chemistry, Processing, and Applications

    NARCIS (Netherlands)

    Myhre, M.; Saiwari, Sitisaiyidah; Dierkes, Wilma K.; Noordermeer, Jacobus 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

  18. 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.

  19. Reassessment of anoxic storage of ethnographic rubber

    DEFF Research Database (Denmark)

    Shashoua, Yvonne; Dyer, Joanne; Ward, Clare

    2011-01-01

    This paper revisits the 1991–1995 British Museum field trial on anoxic storage, where 23 registered ethnographic rubber objects were enclosed in oxygen barrier film Cryovac BDF200 with sachets of the oxygen absorbent Ageless Z. A unique opportunity for study was presented since most of the enclos...

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

    International Nuclear Information System (INIS)

    Kiyan, Ludmila de Ysasa Pozzo

    2014-01-01

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

  1. Preparation of sulfonic acid-containing rubbers from natural rubber vulcanizates

    Science.gov (United States)

    Poonsawat, Worapong; Poompradub, Sirilux; Ngamcharussrivichai, Chawalit

    2014-06-01

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

  2. Chlorinated rubbers with advanced properties for tire industry

    Science.gov (United States)

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

    2017-12-01

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

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

    International Nuclear Information System (INIS)

    Matsuda, Akihiro; Yabana, Shuichi

    2000-01-01

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

  4. A Blue Lagoon Function

    DEFF Research Database (Denmark)

    Markvorsen, Steen

    2007-01-01

    We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$.......We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$....

  5. Assessment of thermal effects in a model of the human head implanted with a wireless active microvalve for the treatment of glaucoma creating a filtering bleb

    Science.gov (United States)

    Schaumburg, F.; Guarnieri, F. A.

    2017-05-01

    A 3D anatomical computational model is developed to assess thermal effects due to exposure to the electromagnetic field required to power a new investigational active implantable microvalve for the treatment of glaucoma. Such a device, located in the temporal superior eye quadrant, produces a filtering bleb, which is included in the geometry of the model, together with the relevant ocular structures. The electromagnetic field source—a planar coil—as well as the microvalve antenna and casing are also included. Exposure to the electromagnetic field source of an implanted and a non-implanted subject are simulated by solving a magnetic potential formulation, using the finite element method. The maximum SAR10 is reached in the eyebrow and remains within the limits suggested by the IEEE and ICNIRP standards. The anterior chamber, filtering bleb, iris and ciliary body are the ocular structures where more absorption occurs. The temperature rise distribution is also obtained by solving the bioheat equation with the finite element method. The numerical results are compared with the in vivo measurements obtained from four rabbits implanted with the microvalve and exposed to the electromagnetic field source.

  6. Prostate-derived sterile 20-like kinase 1-alpha induces apoptosis. JNK- and caspase-dependent nuclear localization is a requirement for membrane blebbing.

    Science.gov (United States)

    Zihni, Ceniz; Mitsopoulos, Costas; Tavares, Ignatius A; Baum, Buzz; Ridley, Anne J; Morris, Jonathan D H

    2007-03-02

    We have demonstrated previously that full-length prostate-derived sterile 20-like kinase 1-alpha (PSK1-alpha) binds to microtubules via its C terminus and regulates their organization and stability independently of its catalytic activity. Here we have shown that apoptotic and microtubule-disrupting agents promote catalytic activation, C-terminal cleavage, and nuclear translocation of endogenous phosphoserine 181 PSK1-alpha and activated N-terminal PSK1-alpha-induced apoptosis. PSK1-alpha, unlike its novel isoform PSK1-beta, stimulated the c-Jun N-terminal kinase (JNK) pathway, and the nuclear localization of PSK1-alpha and its induction of cell contraction, membrane blebbing, and apoptotic body formation were dependent on JNK activity. PSK1-alpha was also a caspase substrate, and the broad spectrum caspase inhibitor benzyloxycarbonyl-VAD-fluoromethyl ketone or mutation of a putative caspase recognition motif ((916)DPGD(919)) blocked nuclear localization of PSK1-alpha and its induction of membrane blebs. Additional inhibition of caspase 9 was needed to prevent cell contraction. PSK1-alpha is therefore a bifunctional kinase that associates with microtubules, and JNK- and caspase-mediated removal of its C-terminal microtubule-binding domain permits nuclear translocation of the N-terminal region of PSK1-alpha and its induction of apoptosis.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2015-05-01

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

  9. 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

  10. The Blue Baby Syndrome

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 10. The Blue Baby Syndrome - Nitrate Poisoning in Humans. Deepanjan Majumdar. General Article Volume 8 Issue 10 October 2003 pp 20-30. Fulltext. Click here to view fulltext PDF. Permanent link:

  11. [Blue light and eye health].

    Science.gov (United States)

    Zou, Leilei; Dai, Jinhui

    2015-01-01

    Blue light, with the wavelength between 400 nm and 500 nm, has caused public concern because of the injury to the retinal cells. Meanwhile, it is important in circadian rhythm regulation, scotopic vision and ocular growth. Is the blue light safe? Should it be eliminated from the daily life? Here we review the effect and safety of the blue light.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  13. Energy recycling of plastic and rubber wastes

    International Nuclear Information System (INIS)

    Hussain, R.

    2003-01-01

    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)

  14. Quantitative Electron Tomography of Rubber Composites

    International Nuclear Information System (INIS)

    Staniewicz, Lech; Midgley, Paul; Vaudey, Thomas; Degrandcourt, Christophe; Couty, Marc; Gaboriaud, Fabien

    2014-01-01

    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

  15. Quantitative Electron Tomography of Rubber Composites

    Science.gov (United States)

    Staniewicz, Lech; Vaudey, Thomas; Degrandcourt, Christophe; Couty, Marc; Gaboriaud, Fabien; Midgley, Paul

    2014-06-01

    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.

  16. Radiation processing of natural rubber latex

    International Nuclear Information System (INIS)

    Makuuchi, K.; Markovic, V.

    1991-01-01

    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

  17. Development of rubber material for high radiation field

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  18. 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.

  19. 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%.

  20. The enzymatic synthesis of rubber polymer in Parthenium argentatum Gray

    International Nuclear Information System (INIS)

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

    1990-01-01

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

  1. 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...... of flaps with voids in chord- or spanwise direction. Development of rubber flaps has involved further design improvements. Non-metallic spring elements and solutions for sealing of continuous extruded rubber profiles have been investigated....

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

    Science.gov (United States)

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

  3. Polypropylene-rubber blends 2: the effect of the rubber content and temperature on the fracture behaviour at low and high test speed

    NARCIS (Netherlands)

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

    1999-01-01

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

  4. Crumb Rubber Recycling in Enhancing Damping Properties of Concrete

    Science.gov (United States)

    Sugapriya, P.; Ramkrishnan, R.

    2018-02-01

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

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

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  6. Biodiesel production methods of rubber seed oil: a review

    Science.gov (United States)

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

    2018-03-01

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

  7. HPSEC Analysis of Ester-Based Polyurethane Rubber Materials

    National Research Council Canada - National Science Library

    Napadensky, Eugene

    2000-01-01

    ... (TACOM) at Picatinny Arsenal, NJ, to evaluate the environmental and operational stability of candidate commercial polyester-polyurethane rubber materials for possible fuel bladder and containment applications...

  8. Radiation vulcanization of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    Dela Rosa, Alumanda M.; Abad, Lucille V.; Sta, Lorna P.; Ana-Relleve; Tranquilan-Aranilla, Charito O.; Pascual, Cristina L.

    1996-01-01

    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

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

    DEFF Research Database (Denmark)

    Pettinari, Matteo; Simone, Andrea

    2015-01-01

    asphalt design. The mix design represents a key phase of the cold mix production. The study of workability and compactability properties combined with a deep laboratory investigation is required. The idea of introducing crumb rubber in the cold mixtures was developed based on the concept of maximizing...... 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...

  10. 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)

    Silva, Andre L.S. da; Lutckmeier, Rafael; Azeredo, Luciane K. de; Jacobi, Marly A.M.

    2011-01-01

    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)

  11. Intoxication of host cells by the T3SS phospholipase ExoU: PI(4,5)P2-associated, cytoskeletal collapse and late phase membrane blebbing.

    Science.gov (United States)

    Sato, Hiromi; Frank, Dara W

    2014-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen that is associated with hospital-acquired infections, ventilator-associated pneumonia, and morbidity of immunocompromised individuals. A subpopulation of P. aeruginosa encodes a protein, ExoU, which exhibits acute cytotoxicity. Toxicity is directly related to the phospholipase A2 activity of the protein after injection into the host cytoplasm via a type III secretion system. ExoU enzymatic activity requires eukaryotic cofactors, ubiquitin or ubiquitin-modified proteins. When administered extracellularly, ExoU is unable to intoxicate epithelial cells in culture, even in the presence of the cofactor. Injection or transfection of ExoU is necessary to observe the acute cytotoxic response. Biochemical approaches indicate that ExoU possesses high affinity to a multifunctional phosphoinositide, phosphatidylinositol 4,5-bisphosphate or PI(4,5)P2 and that it is capable of utilizing this phospholipid as a substrate. In eukaryotic cells, PI(4,5)P2 is mainly located in the cytoplasmic side of the plasma membrane and anchors adaptor proteins that are involved in cytoskeletal structures, focal adhesions, and plasma membranes. Time-lapse fluorescent microscopy analyses of infected live cells demonstrate that ExoU intoxication correlates with intracellular damage in the early phases of infection, such as disruption of focal adhesions, cytoskeletal collapse, actin depolymerization, and cell rounding. At later time points, a membrane blebbing phenotype was prominent prior to the loss of the plasma membrane integrity and barrier function. Membrane blebbing appears to accelerate membrane rupture and the release of intracellular markers. Our data suggest that in eukaryotic host cells, intracellular ExoU targets and hydrolyzes PI(4,5)P2 on the plasma membrane, causing a subsequent disruption of cellular structures and membrane integrity.

  12. 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.

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

    International Nuclear Information System (INIS)

    2006-01-01

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

  14. 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.

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

    Science.gov (United States)

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

    2016-06-14

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

  16. Low surface energy rubber materials : relationship between network architecture and tack of silicone rubbers

    NARCIS (Netherlands)

    Mikrut, M.

    2007-01-01

    The objective of this work was to investigate the relationship between different factors characterizing the network structure on the tackiness of silicone rubber (PDMS). A custom tack testing device was constructed, based on the existing Tel-Tak principle. The experimental work involved testing the

  17. Silica-reinforced natural rubber with epoxidized low molecular weight rubber as a compatibilizer

    NARCIS (Netherlands)

    Saramolee, P.; Sahakaro, Kannika; Lopattananon, N.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2013-01-01

    This work investigates the effect of epoxidized low molecular weight natural rubber (ELMWNR) in silica-filled NR compounds on processing, mechanical and dynamic mechanical properties. The ELMWNRs with mol% epoxide groups varying from 0-50 and molecular weight in a range of 50,000-60,000 g/mol were

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

    Directory of Open Access Journals (Sweden)

    Xiuying Zhao

    2015-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Penny Setyowati

    1995-06-01

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

  20. Allergenicity of latex rubber products used in South African dental ...

    African Journals Online (AJOL)

    Fourteen latex examination gloves (powdered and non-powdered) and five dental rubber dams, representing 6 brands, from five dental academic institutions were analysed for latex allergens and total protein. Total protein content was determined using the BioRad DC protein assay kit and natural rubber allergen levels ...

  1. Polyacrylamide brush coatings preventing microbial adhesion to silicone rubber

    NARCIS (Netherlands)

    Fundeanu, Irina; van der Mei, Henny C.; Schouten, Arend J.; Busscher, Henk J.

    2008-01-01

    Silicone rubber is a frequently used biomaterial in biomedical devices and implants, yet highly prone to microbial adhesion and the development of a biomaterial-centered infection. Effective coating of silicone rubber to discourage microbial adhesion has thus far been impossible due to the

  2. Research and Application Progress of Silicone Rubber Materials in Aviation

    Directory of Open Access Journals (Sweden)

    HUANG Yanhua

    2016-06-01

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

  3. Characterization of weed flora in rubber trees plantations of Bongo ...

    African Journals Online (AJOL)

    Objectives: the main objective of this study is to characterize the weed floristic diversity of the Bongo rubber trees plantation and to provide a map for sustainable weed management. Methodology and results: a floristic survey of the Para rubber plantations of Bongo (Southeast Côte d'Ivoire) was conducted in 2007 and early ...

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

    International Nuclear Information System (INIS)

    Dahlan Mohd; Abdul Ghani Harun

    1993-01-01

    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

  5. Charcoal byproducts as potential styrene-butadiene rubber composte filler

    Science.gov (United States)

    Carbon black, a byproduct of the petroleum industry, is the world's most predominant filler for rubber composites. In this study, various renewable charcoals in the form of pyrolyzed agricultural byproducts were evaluted as potential carbon-based filler for rubber composites made with carboxylated s...

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

    African Journals Online (AJOL)

    The technologies have been developed and only needs to be adapted to our local conditions. It is hoped that this paper will be instructive to rubber farmers, policy makers, executors of policies or citizens wishing to join the Nigerian rubber farmers in their bid to increase their prosperity or alleviate their poverty.

  7. Effects of Dietary Substitution of Rubber Seed Cake for Groundnut ...

    African Journals Online (AJOL)

    Three hundred (300) five weeks old, Anak broilers were used in a 4-week experiment to determine the effect of dietary substitution of rubber seed cake for groundnut cake on the performance of broilers at the finisher phase. Graded levels of rubber seed cake (0, 25, 50, 75 and 100%) substituted corresponding levels of ...

  8. Effect of Rubber Dam on Arterial Oxygen Saturation in Children.

    Science.gov (United States)

    Nara, Asha; Chour, Rashmi; Narasimman, Jamini; Latti, Pooja; Srinidhi, P B

    2015-06-01

    The placement of rubber dam has the potential to alter the airflow through nasal and oral cavities. Pediatric dentist should be aware whether the use of a rubber dam affects the oxygen saturation (SpO2) in children. To assess the effect of rubber dam on arterial blood SpO2 in children of 6-12 years age. Totally, 60 ASA Class I patients of 6-12 years age, randomly allocated in two groups: Group A: Rubber dam isolation of maxilla and Group B: Isolation of the mandible. A pulse oximeter was used to detect SpO2. To establish a baseline, each patient's SpO2 was recorded every 30 s for 2 min. A rubber dam was then placed which extended over the nose. Class I cavity and glass ionomer cements restoration were performed. The rubber dam was cut to expose the nasal cavities SpO2 were recorded every 30 s for 5 min throughout the procedure. A two-way ANOVA test was applied. In both groups there was no significant difference in SpO2 after rubber dam placement with nose covered or uncovered (P > 0.05). There was no significant change in SpO2 after rubber dam isolation with nose covered or uncovered in children of 6-12 years age.

  9. Treatment of wastewater from rubber industry in Malaysia

    African Journals Online (AJOL)

    GREGORY

    2010-09-20

    Sep 20, 2010 ... remove over 95% biological oxygen demand (BOD) from rubber wastewater ... reduction system. (purple non- sulphur photosynthetic bacteria). Optimum growth in latex rubber sheet wastewater with 0.50% ammonium sulphate and 1 mg/l ... and energy costs of surface aerator, all of these factories had ...

  10. Guayule resin detection and influence on guayule rubber

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  12. Reinforcement of latex rubber by the incorporation of amphiphilic particles

    Science.gov (United States)

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

  13. Flexible diamond-like carbon film coated on rubber

    NARCIS (Netherlands)

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

    2013-01-01

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

  14. Flexible protective diamond-like carbon film on rubber

    NARCIS (Netherlands)

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

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

  15. Screening ten genotypes of natural rubber seedlings ( Hevea ...

    African Journals Online (AJOL)

    A field study was conducted in 2012 and 2013 cropping season at the Research Farm of National Root Crops Research Institute, (NRCRI) Umudike, in Abia State, to screen 10 rubber genotypes collected from Rubber Research Institute of Nigeria for tolerant to drought conditions. The aim was to select tolerant genotypes for ...

  16. Differential responses of two rubber tree clones to chilling stress ...

    African Journals Online (AJOL)

    Chilling stress is one of the most important environmental factors that limit the growth, distribution and yield of rubber tree in China. The effects of chilling stress on the grated plants of two rubber trees clones, GT1 and Wenchang217, were studied by physiological methods in controlled light chamber in order to explore the ...

  17. Page 1 UTILISATION OF RUBBER SEED OL IN THE ...

    African Journals Online (AJOL)

    POLYVINYL CHLORIDE AGAINST THERMAL DEGRADATION. F.E. Okieimen. Department of Chemistry, University of Benin, Benin City, Nigeria. ABSTRACT. Thermal degradation studies on polyvinyl chloride in the presence of rubber seed oil, epoxidized rubber seed oil and metal soaps (barium, cadmium and lead) of the ...

  18. Implication of Climate Variability for Latex Exudates F Rubber Tree ...

    African Journals Online (AJOL)

    Two models were developed and all suggested that variable rubber yield was significantly related to the joint influence of climate elements. The most significant variables identified however were rainfall, temperature and sunshine hours. These three elements had significantly negative effects on rubber yield. Analysis of ...

  19. Effluent Discharge and Stream Pollution by a Rubber Factory: A ...

    African Journals Online (AJOL)

    kofimereku

    State (including the rubber factory of Pamol (Nigeria) Limited discharge their effluents into rivers, streams, ... Nigeria hinterland aquatic systems including the Field 20 Stream where rubber effluents are discharge into .... substantial heat pollution (the temperature of the effluent is sometimes as high as 500C ) have made the ...

  20. Rubber composites cured with sulphur and peroxide and ...

    Indian Academy of Sciences (India)

    Sulphur, peroxide and mixed sulphur/peroxide curing systems were introduced in cross-linking of rubber matrices. The aim was to investigate the influence of curing system composition on ... types of rubber compounds with incorporated untraditional fillers as .... ment is based on the analysis of time dependence of thermal.

  1. Radiation response of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    Dela Rosa, A.M.; Abad, L.V.; Ana-Relleve, L.S.; Tranquilan-Aranilla, C.; Pascual, C.L.

    1998-01-01

    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. 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.

  3. Factors Affecting the Adsorption of Trivalent Chromium Ions by Activated Carbon Prepared from Waste Rubber Tyres

    Directory of Open Access Journals (Sweden)

    Sylvia E. Benjamin

    2017-08-01

    Full Text Available Economic gains are generally the outcome of industrialization and consequently urbanization. However, positive fiscal index generates a negative impact on natural environment sources heaving pollutant burden on soil, air and water. Industries throw tones of contaminated water into soil and water bodies without proper treatment and create a potential threat for both living and non-living species. Chromium in trivalent state (Cr3+ is added in water bodies and soil through waste water from tanneries, cooling water systems, chemical and pulp and paper industries. The present research work aims at the preparation of an inexpensive activated carbon prepared from non- degradable waste scrap rubber tyres. The carbon produced from scrap rubber tyres was activated by 5% solution of BaCl2 and 0.4 N solution of HCl and verified by ethylene blue solution. The adsorption capacity of the Tyre activated carbon (TAC was investigated for different parameters i.e., initial chromium (III ion concentration, activated carbon dosage, contact/ stirring time and pH. The adsorption capacity of TAC depends on the initial metal ion concentration and the TAC dose. pH of the chromium solution effects the adsorption capacity of TAC due to the formation of tetra hydroxochromate(III complexes,. The results show that TAC offers a cost effective reclamation process for the removal of Cr3+ from effluent waters.

  4. AC/TiO2/Rubber Composite Sheet Catalysts; Fabrication, Characterization and Photocatalytic Activities

    Directory of Open Access Journals (Sweden)

    Sriwong Chaval

    2015-01-01

    Full Text Available The AC/TiO2/Rubber (ACTR composite sheets weresuccessfully fabricated by a simply mixing of fixed TiO2 suspension and natural rubber latex (60% HA contents withthe varyingamounts of activated carbon (AC suspension, followed by stirring, pouring into apetri dish mold, drying at room temperature (RT, after that taking out from a mold, reversing and drying again at RT. Then, the as-fabricated ACTR composite sheets were characterized by X-ray diffractometer (XRD, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR, energy dispersive X-ray spectroscopy (EDS and scanning electron microscopy (SEMtechniques. The photocatalytic efficiencies of all ACTR composite sheet samples were evaluated by photo degrading of methylene blue (MB dye solution under UV light irradiation. The results showed that the photocatalytic activity of ACTR sheet with10.0wt%AC loading has the highest efficiency for the photo degradation of MB dye than the other sheets. This is due to the fact that it is relatively with the synergistic effect of well-combined titanium dioxide catalyst and activated carbon adsorbent.

  5. 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.

  6. Hacking Experiment Using USB Rubber Ducky Scripting

    Directory of Open Access Journals (Sweden)

    Benjamin Cannoles

    2017-04-01

    Full Text Available By leaving your computer unlocked while you are away for seconds can give hackers all the time they need to obtain your personal information from your computer. This paper aims to detail the necessary research and development of a USB Rubber Ducky script, to obtain clear text logon id and passwords from a Windows machine, in mere seconds. Each stage is laid out in sections discussing Ducky script, powershell, Mimikatz, and reenabling the vulnerability by breaking down the attack into two parts for Windows 7 and up operating systems.

  7. Filled liquid silicone rubbers: Possibilities and challenges

    DEFF Research Database (Denmark)

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

    2014-01-01

    to ensure better particle dispersion as well as folllowing for film formation properties. We show that the mechanical properties of the films as well as the electrical breakdown strength can be affected, and that the control of the amount of solvent throughout the coating process is essential for solvent......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...

  8. Design, Construction, and Evaluation of Rubber Friction Tester

    Directory of Open Access Journals (Sweden)

    Mehdi Razzaghi Kashani

    2012-12-01

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

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

    NARCIS (Netherlands)

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

    1994-01-01

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

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  12. [Mites (Acari) from rubber trees (Hevea brasiliensis Muell. Arg., Euphorbiaceae) and spontaneous euphorbiaceous in rubber trees cultivation].

    Science.gov (United States)

    Bellini, Marcos R; Feres, Reinaldo J F; Buosi, Renato

    2008-01-01

    Quarterly samples were done in 2001 on three rubber tree plantation in the northwest of the state of São Paulo. Three rubber trees of each locality were sampled. Between the rows of rubber tree four species of spontaneous euphorbiaceous were collected: Chamaesyce hirta, C. hyssopifolia, Euphorbia heterophylla and Phyllanthus tenellus. A total of 8.954 mites of 38 species, belonging to 31 genera of 11 families were collected. Tydeidae and Phytoseiidae had the highest diversity of species, 9 and 7, respectively. The most abundant families were Eriophyidae (3.594), Tydeidae (2.825) and Tenuipalpidae (1.027). The most abundant species on the rubber trees were: phytophagous - Calacarus heveae Feres, Tenuipalpus heveae Baker, Lorryia sp.2, Lorryia formosa Cooreman and Lorryia sp.1; predators - Zetzellia quasagistemas Hernandes & Feres, Pronematus sp., Iphiseiodes zuluagai Denmark & Muma and Euseius citrifolius Denmark & Muma. Among the spontaneous euphorbiaceous, predatory mites were abundantly found on C. hirta and E. heterophylla, mainly Pronematus sp. and E. citrifolius, suggesting that these plants could be important in the maintenance of these predators in the rubber tree cultivation areas. However, plants that can shelter predators and at the same time exert strong competition (nutrients, water etc) to rubber trees, can not be recommended for pest management programs. Studies about competition between rubber trees and spontaneous plants need to be conducted for feasible efficient programs of environmental management, aiming at the control of pest mites of rubber tree.

  13. INDUSTRIAL SAFETY IN THE PRODUCTION OF RUBBER

    Directory of Open Access Journals (Sweden)

    S. V. Danilova

    2015-01-01

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

  14. Multiscale physics of rubber-ice friction

    Science.gov (United States)

    Tuononen, Ari J.; Kriston, András; Persson, Bo

    2016-09-01

    Ice friction plays an important role in many engineering applications, e.g., tires on icy roads, ice breaker ship motion, or winter sports equipment. Although numerous experiments have already been performed to understand the effect of various conditions on ice friction, to reveal the fundamental frictional mechanisms is still a challenging task. This study uses in situ white light interferometry to analyze ice surface topography during linear friction testing with a rubber slider. The method helps to provide an understanding of the link between changes in the surface topography and the friction coefficient through direct visualization and quantitative measurement of the morphologies of the ice surface at different length scales. Besides surface polishing and scratching, it was found that ice melts locally even after one sweep showing the refrozen droplets. A multi-scale rubber friction theory was also applied to study the contribution of viscoelasticity to the total friction coefficient, which showed a significant level with respect to the smoothness of the ice; furthermore, the theory also confirmed the possibility of local ice melting.

  15. Evaluation of polybutadiene rubbers using FTIR spectra

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, L.N.; Schimidt, F., E-mail: lucas@ifg.edu.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Goias (IFG), Goiania, GO (Brazil); Antonio, P.L.; Caldas, L.V.E. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Vieira, S.L. [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Instituto de Fisica

    2017-09-01

    Radiation dosimetry for medical and industrial purposes has increasingly evolved over the last few decades with the introduction of various new detectors. Depending on the properties exhibited for radiation dosimetry, some detectors present their applications in a specific area. From a physics point of view, an ideal dosimeter should be able to measure absorbed dose. In this work, synthetic materials based on polybutadiene rubbers (PBR) were proposed as a new class of radiation detectors. The influence of radiation dose on their properties has been investigated for application in radiation dosimetry. The rubber samples were exposed to absorbed doses from 10 Gy up to 250 Gy, using a {sup 60}Co Gamma Cell-220 system. Their responses were carried out with a Fourier Transform Infrared (FTIR) Spectrometer to investigate the presence of absorbance peaks. The results suggested the existence of a relationship between the absorbed doses and the absorbance peaks associated with stretching (1300-1200 cm{sup -1}), deformation (1450-1340 cm{sup -1}) and vibration (1500-1400 cm{sup -1}) processes in the material. (author)

  16. Synthesis biolubricant from rubber seed oil

    Science.gov (United States)

    Hung, Nguyen Tran Dong; Tuyen, Dang Thi Hong; Viet, Tran Tan

    2017-09-01

    The objective was biolubricant preparation from rubber seed oil (RSO) using polymerization reactor with/without catalyst in batch reactor. Before become reactant in polymerization reaction, a non-edible rubber seed oil was converted into methyl ester by esterification/tranesterification reaction with methanol and acid/base catalyst. The polymerization reaction parameters investigated were reaction time, temperature and weight ratio (catalyst with feed), and their effect on the bio lubricant formation. The result show significant conversion of methyl ester to bio lubricant in the temperature reaction of 160°C, reaction time of 2h min and ratio of super acid catalyst (tetrafluoroboric acid-sHBF4) of 3 %w/w. The resulting products were confirmed by GC-MS, FTIR spectroscopy and also analyzed for the viscosity. The best viscosity value of RSOFAME polymer was 110.6 cSt when the condition polymerization reaction were 160 °C, reaction time 3h, 6 wt% mass ratio of oil:catalyst.

  17. 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.

  18. Performance characteristics of rubber seed oil biodiesel

    Science.gov (United States)

    Liu, P.; Qin, M.; Wu, J.; Chen, B. S.

    2018-01-01

    The lubricity, ignition quality, oxidative stability, low temperature flow property and elastomeric compatibility of rubber seed oil biodiesel(RSM) were evaluated and compared with conventional petro-diesel. The results indicated that RSM and its blends with petro-diesel possessed outstanding lubricity manifested by sharp decrease in wear scar diameters in the high-frequency reciprocating rig(HFRR) testing. They also provided acceptable flammability and cold flow property,although the cetane numbers (CN) and cold filter plugging points(CFPP) of biodiesel blends slightly decreased with increasing contents of petro-diesel. However, RSM proved to be very susceptible to oxidation at elevated temperatures during prolonged oxidation durations, characterized by increased peroxide values, viscosity, acid values and isooctane insolubles. The oxidation stability of RSM could be significantly improved by antioxidants such as BD100, a phenol antioxidant produced by Ciba corporation. Furthermore, RSM provided poor compatibility with some elastomeric rubbers such as polyacrylate, nitrile-butadiene and chloroprene, but was well compatible with the hydrogenated nitrile-butadiene elastomer.

  19. Laterality in the rubber hand illusion.

    Science.gov (United States)

    Ocklenburg, Sebastian; Rüther, Naima; Peterburs, Jutta; Pinnow, Marlies; Güntürkün, Onur

    2011-03-01

    In patient studies, impairments of sense of body ownership have repeatedly been linked to right-hemispheric brain damage. To test whether a right-hemispheric dominance for sense of body ownership could also be observed in healthy adults, the rubber hand illusion was elicited on both hands of 21 left-handers and 22 right-handers. In this illusion, a participant's real hand is stroked while hidden from view behind an occluder, and a nearby visible hand prosthesis is repeatedly stroked in synchrony. Most participants experience the illusionary perception of touch sensations arising from the prosthesis. The vividness of the illusion was measured by subjective self-reports as well as by skin conductance responses to watching the rubber hand being harmed. Handedness did not affect the vividness of the illusion, but a stronger skin conductance response was observed, when the illusion was elicited on the left hand. These findings suggest a right-hemispheric dominance for sense of body ownership in healthy adults.

  20. Evaluation of polybutadiene rubbers using FTIR spectra

    International Nuclear Information System (INIS)

    Oliveira, L.N.; Schimidt, F.; Antonio, P.L.; Caldas, L.V.E.; Vieira, S.L.

    2017-01-01

    Radiation dosimetry for medical and industrial purposes has increasingly evolved over the last few decades with the introduction of various new detectors. Depending on the properties exhibited for radiation dosimetry, some detectors present their applications in a specific area. From a physics point of view, an ideal dosimeter should be able to measure absorbed dose. In this work, synthetic materials based on polybutadiene rubbers (PBR) were proposed as a new class of radiation detectors. The influence of radiation dose on their properties has been investigated for application in radiation dosimetry. The rubber samples were exposed to absorbed doses from 10 Gy up to 250 Gy, using a 60 Co Gamma Cell-220 system. Their responses were carried out with a Fourier Transform Infrared (FTIR) Spectrometer to investigate the presence of absorbance peaks. The results suggested the existence of a relationship between the absorbed doses and the absorbance peaks associated with stretching (1300-1200 cm -1 ), deformation (1450-1340 cm -1 ) and vibration (1500-1400 cm -1 ) processes in the material. (author)

  1. Pyrolysis of Rubber in a Screw Reactor

    Science.gov (United States)

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

    2016-11-01

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

  2. Curing of natural rubber and epoxy adhesive

    International Nuclear Information System (INIS)

    Matawie, A.M.; Sadek, E.M.

    2001-01-01

    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)

  3. 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

  4. Blue phases as photonic crystals

    Science.gov (United States)

    Bohley, Christian; Scharf, Toralf

    2003-12-01

    The Liquid Crystalline Blue Phases (LC BPs) and their diffraction patterns were investigated experimentally and theoretically. We stabilized Blue Phases and measured their diffraction pattern for different wavelengths of monochromatic light with the help of a conoscopic setup of a polarization microscope. Moreover, the diffraction patterns were calculated with the help of a 4x4 matrix method which allows amplitude and phase investigations.

  5. 40 CFR 428.30 - Applicability; description of the solution crumb rubber subcategory.

    Science.gov (United States)

    2010-07-01

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

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

    NARCIS (Netherlands)

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

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

    Tsakiris, Manos; Haggard, Patrick

    2005-01-01

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

  9. Reinforcement effect of soy protein nanoparticles in amine-modified natural rubber latex

    Science.gov (United States)

    Mechanical properties of natural rubber reinforced with soy protein nanoparticles are useful for various rubber applications. However, the properties is further improved by improving interactions between soy protein and rubber. A novel method is used to modify particle surface of natural rubber late...

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

    Directory of Open Access Journals (Sweden)

    Wojciech HOMIK

    2011-01-01

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

  11. Effect of superhydrophobicity on surface damage of silicone rubber under AC voltage

    Directory of Open Access Journals (Sweden)

    Yufeng Li

    2018-03-01

    Full Text Available In this paper, the influence of superhydrophobicity on the surface damage of silicone rubber is studied. On a common silicone rubber surface, a droplet can become elongated, and arc discharge induced by the droplet can cause tracking on the silicone rubber surface. However, for a superhydrophobic silicone rubber surface, a droplet can leave the silicone rubber due to the low adhesion of the superhydrophobic surface. Accordingly, arc discharge caused by the droplet does not occur, and the surface of the silicone rubber is not affected. Results demonstrate that using a superhydrophobic surface has a significant effect on limiting the surface damage of silicone rubber.

  12. Utilization of waste tire rubber in manufacture of oriented strandboard.

    Science.gov (United States)

    Ayrilmis, Nadir; Buyuksari, Umit; Avci, Erkan

    2009-09-01

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

  13. their use as Accelerator in Curing Process of Rubber Compounds

    Directory of Open Access Journals (Sweden)

    S. taghvaee

    2007-06-01

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

  14. Volume Changes in Filled Rubber Under Uniaxial Cyclic Loading

    Directory of Open Access Journals (Sweden)

    Elina KAZINA

    2011-09-01

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

  15. Improving rubber concrete by waste organic sulfur compounds.

    Science.gov (United States)

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

    2010-01-01

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

  16. The optimum content of rubber ash in concrete: flexural strength

    Science.gov (United States)

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

    2017-11-01

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

  17. Fabrication of shape memory natural rubber using palmitic acid

    Directory of Open Access Journals (Sweden)

    Jeff Sze-Hua Wee

    2017-10-01

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

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    A.B. Moustafa

    2016-09-01

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

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

    OpenAIRE

    Salni Salni; Poedji Loekitowati Hariani; Hanifa Marisa Hanifa

    2017-01-01

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

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

    OpenAIRE

    Salni, Salni; Hariani, Poedji Loekitowati; Hanifa, Hanifa Marisa

    2017-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Yan He

    2015-01-01

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

  3. 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.

  4. SUPPLY-CHAIN OF NATURAL RUBBER IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Bustanul Arifin

    2011-08-01

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

  5. 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.

  6. The influence of natural rubber - butadiene rubber and carbon black type on the mechanical properties of tread compound

    Science.gov (United States)

    Wisojodharmo, L. A.; Fidyaningsih, R.; Fitriani, D. A.; Arti, D. K.; Indriasari; Susanto, H.

    2017-07-01

    The objective of this study is to optimize the performance of the tread compound, by mixing of specified ingredients, such as Natural Rubber (NR) and Butadiene Rubber (BR) at various compositions, and also the type of carbon black as filler. The composition of NR and BR are used as follows 100:0; 95:5 and 85:15. Other materials used as rubber additives are peptizer, ZnO, stearic acid, additives, processing oil, and curatives. Two types of carbon black namely N220 and N234 are used in this research. The un-vulcanized rubber from each formula was characterized of curing characteristics and Mooney viscosity. The vulcanized rubber was then characterized its mechanical and thermal properties. It is clear from the research that, the addition of BR into the NR compound increases the abrasion resistance, rebound resilience and hardness, yet the glass transition temperature of the rubber compounds decreases. On the other hand, it seems that the rubber compound reinforced N220 or N234 gives comparable results on both mechanical and thermal properties.

  7. Revisión con agujas y uso de mitomicina C en bulas de filtración encapsuladas Needle revision and use of Mitomycin-C to manage encapsulated filtering blebs

    Directory of Open Access Journals (Sweden)

    Francisco Fumero González

    2012-01-01

    Full Text Available La trabeculectomía es uno de los tratamientos de elección en los pacientes con glaucoma. La causa más común de fallo de esta cirugía en su primer trimestre es la bula de filtración encapsulada. Usualmente es resultado de la proliferación fibrótica subconjuntival que lleva a fallo de la bula, como por ejemplo en los glaucomas traumáticos. La revisión con agujas y la mitomicina C constituyen una opción efectiva y relativamente segura para restaurar la función de la cirugía de filtración. Se presenta un paciente donde se restableció el flujo de humor acuso con este proceder.Trabeculectomy is the surgical treatment of choice for many patients with glaucoma. The most common cause of failure during the first trimester after trabeculectomy is encapsulated bleb. Generally, that results from scarring in the subconjunctival space with a resultant intrableb fibrosis and the development of a failed bleb, for example in traumatic glaucoma. Needling bleb revision with mitomycin-C appears to be an effective and relatively safe way to revive the function of the filtration surgery. This was the case report of a patient whose aqueous humor flow was reestablished with this treatment.

  8. Blue moons and Martian sunsets.

    Science.gov (United States)

    Ehlers, Kurt; Chakrabarty, Rajan; Moosmüller, Hans

    2014-03-20

    The familiar yellow or orange disks of the moon and sun, especially when they are low in the sky, and brilliant red sunsets are a result of the selective extinction (scattering plus absorption) of blue light by atmospheric gas molecules and small aerosols, a phenomenon explainable using the Rayleigh scattering approximation. On rare occasions, dust or smoke aerosols can cause the extinction of red light to exceed that for blue, resulting in the disks of the sun and moon to appear as blue. Unlike Earth, the atmosphere of Mars is dominated by micron-size dust aerosols, and the sky during sunset takes on a bluish glow. Here we investigate the role of dust aerosols in the blue Martian sunsets and the occasional blue moons and suns on Earth. We use the Mie theory and the Debye series to calculate the wavelength-dependent optical properties of dust aerosols most commonly found on Mars. Our findings show that while wavelength selective extinction can cause the sun's disk to appear blue, the color of the glow surrounding the sun as observed from Mars is due to the dominance of near-forward scattering of blue light by dust particles and cannot be explained by a simple, Rayleigh-like selective extinction explanation.

  9. Superhydrophobic RTV silicone rubber insulator coatings

    Science.gov (United States)

    Seyedmehdi, Seyed Amirhossein; Zhang, Hui; Zhu, Jesse

    2012-01-01

    On wet days, environmental contamination of outdoor insulation surfaces can reduce the reliability of electrical transmission systems and lead to flashover and arcing over the entire insulator. The use of superhydrophobic coatings would resolve this problem due to their self-cleaning effect. Water droplets can pick up dirt particles and remove contamination from the surfaces of insulators. This paper reports on a study to make a superhydrophobic RTV silicone rubber coating that has contact angles of higher than 145° and good UV durability. The Inclined Plane Test, water durability test and adhesion test are presented to show the effectiveness of this coating and the best formulations. The results of tracking and erosion resistance test (Inclined Plane Test) showed that formulations with at least 35 wt% ATH can be used for superhydrophobic RTV insulator coatings.

  10. The rubber hand illusion in a mirror.

    Science.gov (United States)

    Bertamini, Marco; Berselli, Nausicaa; Bode, Carole; Lawson, Rebecca; Wong, Li Ting

    2011-12-01

    In the rubber hand illusion (RHI) one's hand is hidden, and a fake hand is visible. We explored the situation in which visual information was available indirectly in a mirror. In the mirror condition, compared to the standard condition (fake hand visible directly), we found no reduction of the RHI following synchronised stimulation, as measured by crossmanual pointing and by a questionnaire. We replicated the finding with a smaller mirror that prevented visibility of the face. The RHI was eliminated when a wooden block replaced the fake hand, or when the hand belonged to another person or mannequin. We conclude that awareness of the reflection is the critical variable, despite the distant visual localisation of the hand in a mirror and the third-person perspective. Stimuli seen in a mirror activate the same response as stimuli seen in peripersonal space, through knowledge that they are near one's body. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. 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

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

    Science.gov (United States)

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

  13. 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...

  14. Lightweight Metal RubberTM Sensors and Interconnects, Phase II

    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...

  15. Experimental Study and Dynamic Modeling of Metal Rubber Isolating Bearing

    International Nuclear Information System (INIS)

    Zhang, Ke; Zhou, Yanguo; Jiang, Jian

    2015-01-01

    In this paper, dynamic shear mechanical properties of a new metal rubber isolating bearing is tested and studied. The mixed damping model is provided for theoretical modeling of MR isolating bearing, the shear stiffness and damping characteristics of the MR bearing can be analyzed separately and easily discussed, and the mixed damping model is proved to be an rather effective approach. The test results indicate that loading frequency bears little impact over shear property of metal rubber isolating bearing, the total energy consumption of metal rubber isolating bearing increases with the increase in loading amplitude. With the increase in loading amplitude, the stiffness of the isolating bearing will reduce showing its “soft property”; and the type of damping force gradually changes to be close to dry friction. The features of “soft property” and dry friction energy consumption of metal rubber isolating bearing are very useful in practical engineering application. (paper)

  16. Polyacrylamide brush coatings preventing microbial adhesion to silicone rubber.

    Science.gov (United States)

    Fundeanu, Irina; van der Mei, Henny C; Schouten, Arend J; Busscher, Henk J

    2008-07-15

    Silicone rubber is a frequently used biomaterial in biomedical devices and implants, yet highly prone to microbial adhesion and the development of a biomaterial-centered infection. Effective coating of silicone rubber to discourage microbial adhesion has thus far been impossible due to the hydrophobic character of its surface, surface deterioration upon treatment and instability of coatings under physiological conditions. Here we present a method to successfully grow polyacrylamide (PAAm) brushes from silicone rubber surfaces after removal of low molecular weight organic molecules (LMWOM), such as silane oligomers. PAAm brush coating did not cause any surface deterioration and discouraged microbial adhesion, even after 1-month exposure to physiological fluids. The method presented opens many new avenues for the use of silicone rubber as a biomaterial, without the risk of developing a biomaterial-centered infection.

  17. 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.

  18. Metal Rubber Sensor Appliqus for Rotor Blade Air, Phase II

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2017-06-01

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

  20. Method for Molding Structural Parts Utilizing Modified Silicone Rubber

    Science.gov (United States)

    Weiser, Erik S. (Inventor); Baucom, Robert M. (Inventor); Snoha, John J. (Inventor)

    1998-01-01

    This invention improves upon a method for molding structural parts from preform material. Preform material to be used for the part is provided. A silicone rubber composition containing entrained air voids is prepared. The silicone rubber and preform material assembly is situated within a rigid mold cavity used to shape the preform material to die desired shape. The entire assembly is heated in a standard heating device so that the thermal expansion of the silicone rubber exerts the pressure necessary to force the preform material into contact with the mold container. The introduction of discrete air voids into the silicone rubber allows for accurately controlled pressure application on the preform material at the cure temperature.

  1. Permeation Behavior and Physical Properties of Natural Rubber Nanocomposites

    National Research Council Canada - National Science Library

    Zukas, Walter; Sennett, Michael; Welsh, Elizabeth; Rodriguez, Axel; Ziegler, David; Touchet, Paul

    2004-01-01

    .... A study was carried out to examine the effects of varying nanoparticle morphology and composition on the mechanical and barrier properties of polymer nanocomposites made with natural rubber (NR...

  2. 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...

  3. 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

  4. Photometry of faint blue stars

    International Nuclear Information System (INIS)

    Kilkenny, D.; Hill, P.W.; Brown, A.

    1977-01-01

    Photometry on the uvby system is given for 61 faint blue stars. The stars are classified by means of the Stromgren indices, using criteria described in a previous paper (Kilkenny and Hill (1975)). (author)

  5. Ecology of blue straggler stars

    CERN Document Server

    Carraro, Giovanni; Beccari, Giacomo

    2015-01-01

    The existence of blue straggler stars, which appear younger, hotter, and more massive than their siblings, is at odds with a simple picture of stellar evolution. Such stars should have exhausted their nuclear fuel and evolved long ago to become cooling white dwarfs. They are found to exist in globular clusters, open clusters, dwarf spheroidal galaxies of the Local Group, OB associations and as field stars. This book summarises the many advances in observational and theoretical work dedicated to blue straggler stars. Carefully edited extended contributions by well-known experts in the field cover all the relevant aspects of blue straggler stars research: Observations of blue straggler stars in their various environments; Binary stars and formation channels; Dynamics of globular clusters; Interpretation of observational data and comparison with models. The book also offers an introductory chapter on stellar evolution written by the editors of the book.

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

    OpenAIRE

    K. Sridharan; R. Sivaramakrishnan

    2013-01-01

    The Elastomeric materials have found use in a wide range of applications, including hoses, tires, gaskets, seals, vibration isolators, bearings and dock fenders. The analysis of rubber blocks for its compression and shear behavior has been carried out using the imaging techniques. The dynamic stressing and its associated change in shape of the rubber blocks during large compression are very limited as their measurements were difficult. A newly developed Machine Vision based image processing t...

  7. Purification and Some Properties of Rubber Seed Lipoxygenase ...

    African Journals Online (AJOL)

    ... 49,000 and 107,000 daltons. The rubber seed lipoxygenase had two ionizing groups at the pK values of 4.8 and 7.3. It also had pK values of 5.2 and 7.5 as the ionization constants of the free enzyme. The activation energy (Ea) of the rubber seed lipoxygenase was 7.2 kcal/mole and the enthalpy (DH) was 5.3 kcal/mole.

  8. Studies on Hydrogenation of Liquid Natural Rubber Using Diimide

    Directory of Open Access Journals (Sweden)

    Nur Hanis Adila Azhar

    2015-01-01

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

  9. Neutron absorbing room temperature vulcanizable silicone rubber compositions

    International Nuclear Information System (INIS)

    Zoch, H.L.

    1979-01-01

    A neutron absorbing composition is described and consists of a one-component room temperature vulcanizable silicone rubber composition or a two-component room temperature vulcanizable silicone rubber composition in which the composition contains from 25 to 300 parts by weight based on the base silanol or vinyl containing diorganopolysiloxane polymer of a boron compound or boron powder as the neutron absorbing ingredient. An especially useful boron compound in this application is boron carbide. 20 claims

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Florina Carmen Ciornei

    2016-12-01

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

  12. The water-food nexus of natural rubber production

    Science.gov (United States)

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

    2017-12-01

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

  13. 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.

  14. 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.

  15. Rheological Properties of Rubber Compounds with Finely Divided Carbon Additives

    Science.gov (United States)

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

    2018-01-01

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

  16. Laboratory Evaluation of Ground Tire Rubber in Stone Mastic Asphalt

    Directory of Open Access Journals (Sweden)

    R. Muniandy

    2004-12-01

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

  17. [Acute blue urticaria following subcutaneous injection of patent blue dye].

    Science.gov (United States)

    Hamelin, A; Vial-Dupuy, A; Lebrun-Vignes, B; Francès, C; Soria, A; Barete, S

    2015-11-01

    Patent blue (PB) is a lymphatic vessel dye commonly used in France for sentinel lymph node detection in breast cancer, and less frequently in melanoma, and which may induce hypersensitivity reactions. We report a case of acute blue urticaria occurring within minutes of PB injection. Ten minutes after PB injection for sentinel lymph node detection during breast cancer surgery, a 49-year-old woman developed generalised acute blue urticaria and eyelid angioedema without bronchospasm or haemodynamic disturbance, but requiring discontinuation of surgery. Skin testing using PB and the anaesthetics given were run 6 weeks after the episode and confirmed PB allergy. PB was formally contra-indicated. Immediate hypersensitivity reactions to PB have been reported for between 0.24 and 2.2% of procedures. Such reactions are on occasion severe, chiefly involving anaphylactic shock. Two mechanisms are probably associated: non-specific histamine release and/or an IgE-mediated mechanism. Skin tests are helpful in confirming the diagnosis of PB allergy. Blue acute urticaria is one of the clinical manifestations of immediate hypersensitivity reactions to patent blue dye. Skin tests must be performed 6 weeks after the reaction in order to confirm the diagnosis and formally contra-indicate this substance. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  18. Studies on gamma irradiated rubber materials

    Science.gov (United States)

    Lungu, I. B.; Stelescu, M. D.; Cutrubinis, M.

    2018-01-01

    Due to the increase in use and production of polymer materials, there is a constant pressure of finding a solution to more environmental friendly composites. Beside the constant effort of recycling used materials, it seems more appropriate to manufacture and use biodegradable and renewable row materials. Natural polymers like starch, cellulose, lignin etc are ideal for preparing biodegradable composites. Some of the dynamic markets that use polymer materials are the food and pharmaceutical industries. Because of their desinfastation and sometimes sterility requirements, different treatment processes are applied, one of it being radiation treatment. The scope of this paper is to analyze the mechanical behaviour of rubber based materials irradiated with gamma rays at four medium doses, 30.1 kGy, 60.6 kGy, 91 kGy and 121.8 kGy. The objectives are the following: to identify the optimum radiation dose in order to obtain a good mechanical behaviour and to identify the mechanical behaviour of the material when adding different quantities of natural filler (20 phr, 60 phr and 100 phr).

  19. Electrical properties of filled silicone rubber

    Science.gov (United States)

    Tuncer, Enis; Gubanski, Stanislaw M.

    2000-02-01

    Rubber materials for high-voltage outdoor applications have been studied. They were prepared as mixtures of silicone polymer with different concentrations of powdered aluminium trihydrate as a filler. The dielectric properties, icons/Journals/Common/chi" ALT="chi" ALIGN="TOP"/> *(icons/Journals/Common/omega" ALT="omega" ALIGN="TOP"/> ) = icons/Journals/Common/chi" ALT="chi" ALIGN="TOP"/> ´-iicons/Journals/Common/chi" ALT="chi" ALIGN="TOP"/> ´´, were measured at different temperatures using a low-frequency dielectric spectroscopy technique. Without any filler a classical interfacial relaxation was pronounced with dominating direct-current (dc) conduction in the losses, icons/Journals/Common/chi" ALT="chi" ALIGN="TOP"/> ´´. On increasing the concentration of filler, a low-frequency dispersion mechanism started to dominate the relaxation behaviour. On adding the filler, the dc conduction first decreased and then increased again after a certain concentration level was passed. This behaviour showed that the filler particles acted like scattering centres or traps for conduction when the concentration was low. As the concentration increased, the conductivity of the filler particles and of the interface (between the filler particles and the polymer matrix) started to dominate the conduction. Master curve shifts of the data showed an Arrhenius type of activation. The data were modelled by superposition of three different processes, Havriliak-Negami dipolar relaxation, dc conduction and low-frequency dispersion (hopping conduction) contributions, using a nonlinear least-squares fitting method.

  20. Ultrafast crosslinking of styrene-butadiene rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Decker, C.; Trieu, N.T.V. [CNRS, Mulhouse (France). Dept. de Photochimie

    2000-07-01

    Thermoplastic elastomers, like styrene-butadiene rubbers (SBS), are usually made of triblock copolymers which form segregated glassy and elastomeric domains. These polymeric materials exhibit a high elasticity and resiliency, but a poor resistance to organic solvents. Moreover, they start to flow upon heating above 80 C, the polystyrene glass transition temperature, when the physical network loses its cohesion. An effective way to make these polymers more resistant to solvents and elevated temperatures, as required for hot-melt adhesive applications, is to create covalent bonds between the elastomeric chains. Such a chemical network can be readily formed by photoinitiated crosslinking through the vinyl and butene double bonds located on the polybutadiene chain. Upon UV-curing, the shear adhesion failure temperature (SAFT) was found to rise from 80 C to over 160 C, while the polymer remained tacky and became completely insoluble. The main advantage of photoinitiation is that crosslinking is achieved within seconds at ambient temperature, selectively in the illuminated areas, by a solvent-free process. This technology is therefore of great interest for adhesives and sealants applications, as well as for the manufacture of flexographic printing plates. We report here how the curing performance of photosensitive SBS-based resins can be substantially improved by using a trifunctional thiol as crosslinking agent. (orig.)

  1. Blue-emitting laser diodes

    Science.gov (United States)

    Nakano, K.; Ishibashi, A.

    This paper reviews the recent results of blue-emitting laser diodes. These devices are based on ZnMgSSe alloy II-VI semiconductors. Recently we have achieved room temperature continuous-wave operation of ZnMgSSe blue lasers for the first time. ZnMgSSe alloys offer a wide range of band-gap energy from 2.8 to 4.5 eV, while maintaining lattice matching to GaAs substrates. These characteristics make ZnMgSSe suitable for cladding layers of blue lasers. In this article, the feasibilities of ZnMgSSe will be reviewed. The laser structures and characteristics will be also mentioned.

  2. 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

  3. Synthesis and characterization of silver nanoparticles in natural rubber

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  4. Viscoelasticity evaluation of rubber by surface reflection of supersonic wave.

    Science.gov (United States)

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

    2006-12-22

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

  5. Natural Rubber Nanocomposite with Human-Tissue-Like Mechanical Characteristic

    Science.gov (United States)

    Murniati, Riri; Novita, Nanda; Sutisna; Wibowo, Edy; Iskandar, Ferry; Abdullah, Mikrajuddin

    2017-07-01

    The blends of synthetic rubber and natural rubber with nanosilica were prepared using a blending technique in presence of different filler volume fraction. The effect of filler on morphological and mechanical characteristics was studied. Utilization of human cadaver in means of medical study has been commonly used primarily as tools of medical teaching and training such as surgery. Nonetheless, human cadaver brought inevitable problems. So it is necessary to find a substitute material that can be used to replace cadavers. In orthopaedics, the materials that resemble in mechanical properties to biological tissues are elastomers such as natural rubber (latex) and synthetic rubber (polyurethanes, silicones). This substitution material needs to consider the potential of Indonesia to help the development of the nation. Indonesia is the second largest country producer of natural rubber in the world. This paper aims to contribute to adjusting the mechanical properties of tissue-mimicking materials (TMMs) to the recommended range of biological tissue value and thus allow the development of phantoms with greater stability and similarity to human tissues. Repeatability for the phantom fabrication process was also explored. Characteristics were then compared to the control and mechanical characteristics of different human body part tissue. Nanosilica is the best filler to produce the best nanocomposite similarities with human tissue. We produced composites that approaching the properties of human internal tissues.

  6. EVALUATION OF TIRE RUBBER DISPOSAL IN CONCRETE FOR PAVEMENTS

    Directory of Open Access Journals (Sweden)

    Rosa Cristina Cecche Lintz

    2009-01-01

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

  7. 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.

  8. Alexithymia Modulates the Experience of the Rubber Hand Illusion

    Directory of Open Access Journals (Sweden)

    Delphine eGrynberg

    2015-06-01

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

  9. Degrading radiation effects on properties of bromobutyl rubber compounds

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  10. Tensile Strength of PHBV/Natural Rubber Latex Mixtures

    Directory of Open Access Journals (Sweden)

    Promkotra Sarunya

    2015-01-01

    Full Text Available A polyhydroxybutyrate-co-hydroxyvalerate (PHBV is mingled with natural rubber latex (R to develop its mechanical property of the blend. Normally, substantial effects of the PHBV are hard, fragile, and inelastic, whereas the natural rubber is represented itself as very high elastic matter. The mixtures between the PHBV and natural rubber latex (R are considered in different proportions. The PHBV solutions (w/v are defined suitability at 1% (P1, 2% (P2, and 3% (P3. Their liquid mixtures of the PHBV to natural rubber latex (P:R are fabricated the blended films in three different ratios of 2:3, 1:1 and 3:2, respectively. The PHBV blended films are characterized the crystallinity form by x-ray diffractometry (XRD, which are appeared their identity crystals at 13.30 and 16.68 degree (2θ. Mechanical characterizations of the blends are examined by a universal testing machine (UTM. The average elastic moduli of P1, P2, and P3 mixtures are indicated as 773, 955, and 1,007 kPa, respectively. Their tensile strengths, similarly to elastic moduli, enhance with the PHBV concentrations. The effects of mechanical behaviors and crystallinity reveal that the PHBV blends can be improved their properties by more flexible with natural rubber latex.

  11. Surface improvement of EPDM rubber by plasma treatment

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  12. Flashover Characteristics of Silicone Rubber Sheets under Various Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Arshad

    2016-08-01

    Full Text Available Silicone rubber insulators are replacing the conventional ceramic and porcelain insulators rapidly in power transmission and distribution industry. Very limited field knowledge is available about the performance of silicone rubber insulators in polluted and contaminated environments and therefore need further investigation. A comprehensive analysis of silicone rubber sheets (intended for coating outdoor insulators was carried out in this paper based on experimental results. The main performance parameters analyzed were arc inception voltage and flashover voltage. Dependence of these parameters on equivalent salt deposit density (ESDD, non-soluble salt deposit density (NSDD, relative humidity, ambient temperature, fog rate, dry band formation, dry band location and number of dry bands were investigated extensively. Insulator orientation and its effect on performance were also studied. The authors believe that this paper will provide a comprehensive knowledge about the flashover characteristics of silicone rubber insulators under humid, contaminated and dry band conditions. These results could be used in the selection and design of silicone rubber insulators for polluted environments.

  13. 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.

  14. Vulcanization Kinetics of Natural Rubber Based On Free Sulfur Determination

    Directory of Open Access Journals (Sweden)

    Abu Hasan

    2013-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Fábio Luiz Partelli

    2014-11-01

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

  16. Behaviour of Steel Fibre Reinforced Rubberized Continuous Deep Beams

    Science.gov (United States)

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

    2018-03-01

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

  17. Blue light emitting thiogallate phosphor

    Science.gov (United States)

    Dye, Robert C.; Smith, David C.; King, Christopher N.; Tuenge, Richard T.

    1998-01-01

    A crystalline blue emitting thiogallate phosphor of the formula RGa.sub.2 S.sub.4 :Ce.sub.x where R is selected from the group consisting of calcium, strontium, barium and zinc, and x is from about 1 to 10 atomic percent, the phosphor characterized as having a crystalline microstructure on the size order of from about 100 .ANG. to about 10,000 .ANG. is provided together with a process of preparing a crystalline blue emitting thiogallate phosphor by depositing on a substrate by CVD and resultant thin film electroluminescent devices including a layer of such deposited phosphor on an ordinary glass substrate.

  18. 75 FR 17827 - Goodyear Tire & Rubber Company, Grant of Petition for Decision of Inconsequential Noncompliance

    Science.gov (United States)

    2010-04-07

    ... National Highway Traffic Safety Administration Goodyear Tire & Rubber Company, Grant of Petition for Decision of Inconsequential Noncompliance Goodyear Tire & Rubber Company (Goodyear), has determined that... recycling industries must also be considered. Although tire construction affects the strength and durability...

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

    Science.gov (United States)

    Zhang, Tao; Cai, Guojun; Duan, Weihong

    2018-02-01

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

  20. Acceleration on the Growth of Rubber Planting Materials by Using Foliar Application of Humic Acid

    OpenAIRE

    Cahyo, Andi Nur; Ardika, Risal; Saputra, Jamin; Wijaya, Thomas

    2014-01-01

    The best rubber planting materials are needed to build the best rubber plantation. Humic acids could be used to improve the growth of rubber planting materials. Humic acid plays a role as a hormone-like substance. This research was aimed to determine the optimal concentration of foliar application of humic acid in order to enhance the growth of rubber tree planting materials. This research was arranged in a completely randomized block design with five treatments and four replicates. The treat...

  1. The Changes of Carbon Stocks on Rejuvenation of Smallholder Rubber Plantation

    OpenAIRE

    Supriadi, Handi; Ferry, Yulius

    2014-01-01

    Rejuvenation of rubber tree (Hevea Brasiliensis) can lead to a reduction of carbon stocks. Therefore, appropriate methods are needed to minimize such losses. The objective of this study was to analyze the changes on carbon stocks in the rejuvenation of rubber with logging system of 30%, 50%, 70%, and 100% and intercrops between the young rubber plantation (maize and peanuts). The research was conducted from January to December 2013 at smallholder rubber plantation in Way Tuba District, Way Ka...

  2. Investigation of contamination caused by rubber compactor in arsine purified in gas centrifuge

    OpenAIRE

    Zaykov, А. А.; Zyryanov, S. М.; Kulinich, Yu. А.; Pulnikov, I. I.; Skorynin, G. М.; Vlasov, V. А.

    2007-01-01

    In the process of studying the application of gas centrifuges for deep purification of arsine from impurities sulphur was found. Estimation of quantitative content of sulphur in pure arsine showed the value -10-4 wt. %. The sources of sulphur was stated to be rubber compactors forming gas centrifuge complex and made from rubber on the basis of butadiene_nitrile caoutchouc using sulfur cure. Using rubber compactors made from rubber produced from fluoroelastomers, not undergoing to sulfur cure ...

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

    OpenAIRE

    Yue Lian-yong; Li Wei; Zu Xu-dong; Huang Zheng-xiang; Gao Zhen-yu

    2016-01-01

    Natural rubber is reinforced with carbon fiber; the protective performances of the carbonfiber reinforced rubber composite armour to shaped charge jet have been studied based on the depth of penetration experiments. The craters on the witness blocks, the nature rubber based composite plates’ deformation and the Scanning Electron Microscopy for the hybrid fiber reinforced rubber plate also is analyzed. The results showed that the composite armour can affect the stability of the jet and made pa...

  4. Study on Load-displacement Test of Rubber Pads of Coal Mine Roadway Constructed by Shield

    Science.gov (United States)

    Yang, Yue; Chen, Xiaoguo; Yang, Liyun

    2017-12-01

    Shield method construction of coal mine roadway is the future trend of the development of deep coal mining. The main shaft supporting is the segment. There is rubber pads between segment and segment. The performance of compression deformation of rubber pad is essential for the overall stability of lining. Through load test, displacement of the rubber pad under load, the thrust force law of the rubber pad deformation, and provide a theoretical basis for the stability analysis of coal mine tunnel shield construction.

  5. Rubber property: compression set induced by nuclear radiation

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The methods cover the testing of vulcanized rubber parts that are to be assembled in such a manner that the rubber will remain subjected to compressive stresses or shear during continuous exposure to high energy radiation. Three methods are covered: compression set under constant load with measurements performed at or near the site of irradiation; compression set under constant deflection with measurements performed at or near the site of irradiation; compression set under constant deflection with measurements performed at a site remote from irradiation facility. Each method includes a discussion of the compression device, test specimens, procedure, calculation, and report. The compression set tests are intended to measure the ability of vulcanized rubber compounds to retain elastic properties during prolonged periods of static loading in a field of high energy radiation

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

    International Nuclear Information System (INIS)

    Atia, M.K.

    2010-01-01

    Styrene-butadiene rubber/lead oxide composites were prepared as γ-radiation shields.The composites were prepared with different concentration of red lead oxide (Pb 3 O 4 ) .The assessment of the linear attenuation coefficient of the SBR/lead oxide composites for γ -rays from 137 Cs 137 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.

  7. 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.

  8. ASSESSMENT OF THE DYNAMIC PROPERTIES OF PLAIN AND RUBBERIZED CONCRETE

    Directory of Open Access Journals (Sweden)

    Ionuţ Ovidiu TOMA

    2015-11-01

    Full Text Available The use of rubber from discarded car tires as an alternative to natural aggregates in concrete may help preventing the complete depletion of natural resources and work towards a sustainable future. Moreover it can significantly reduce the environmental footprint of the construction industry. The assessment of the dynamic properties of a material are very important from the point of view of the energy dissipation capability of the investigated material. This can be determined from the dynamic modulus of elasticity, damping and the loss coefficients of the material. The paper presents the results obtained during an experimental program aimed at assessing the dynamic characteristics of plain and rubberized concrete containing rubber crumbs from discarded car tires. The theoretical background and the investigation methodology are presented with particular application to cylindrical concrete specimens.

  9. Direct molding of pavement tiles made of ground tire rubber

    Science.gov (United States)

    Quadrini, Fabrizio; Gagliardi, Donatella; Tedde, Giovanni Matteo; Santo, Loredana; Musacchi, Ettore

    2016-10-01

    Large rubber products can be molded by using only ground tire rubber (GTR) without any additive or binder due to a new technology called "direct molding". Rubber granules and powders from tire recycling are compression molded at elevated temperatures and pressures. The feasibility of this process was clearly shown in laboratory but the step to the industrial scale was missing. Thanks to an European Project (SMART "Sustainable Molding of Articles from Recycled Tires") this step has been made and some results are reported in this study. The press used for compression molding is described. Some tests were made to measure the energy consumption so as to evaluate costs for production in comparison with conventional technologies for GTR molding (by using binders). Results show that 1 m2 tiles can be easily molded with several thicknesses in a reasonable low time. Energy consumption is higher than conventional technologies but it is lower than the cost for binders.

  10. Nonlinear Viscoelastic Mechanics of Cross-linked Rubbers

    Science.gov (United States)

    Freed, Alan D.; Leonov, Arkady I.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    The paper develops a general theory for finite rubber viscoelasticity, and specifies it in the form, convenient for solving problems important for rubber, tire and space industries. Based on the quasi-linear approach of non-equilibrium thermodynamics, a general nonlinear theory has been developed for arbitrary nonisothermal deformations of viscoelastic solids. In this theory, the constitutive equations are presented as the sum of known equilibrium (rubber elastic) and non-equilibrium (liquid polymer viscoelastic) terms. These equations are then simplified using several modeling arguments. Stability constraints for the proposed constitutive equations are also discussed. It is shown that only strong ellipticity criteria are applicable for assessing stability of the equations governing viscoelastic solids.

  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. Rubber Oxygenase and Latex Clearing Protein Cleave Rubber to Different Products and Use Different Cleavage Mechanisms

    Science.gov (United States)

    Birke, Jakob

    2014-01-01

    Two types of enzyme for oxidative cleavage of poly(cis-1,4-isoprene) are known. One is rubber oxygenase (RoxA) that is secreted by Xanthomonas sp. strain 35Y and a few other Gram-negative rubber-degrading bacteria during growth on polyisoprene. RoxA was studied in the past, and the recently solved structure showed a structural relationship to bacterial cytochrome c peroxidases (J. Seidel et al., Proc. Natl. Acad. Sci. U. S. A. 110:13833–13838, 2013, http://dx.doi.org/10.1073/pnas.1305560110). The other enzyme is latex-clearing protein (Lcp) that is secreted by rubber-degrading actinomycetes, but Lcp has not yet been purified. Here, we expressed Lcp of Streptomyces sp. strain K30 in a ΔroxA background of Xanthomonas sp. strain 35Y and purified native (untagged) Lcp. The specific activities of Lcp and RoxA were 0.70 and 0.48 U/mg, respectively. Lcp differed from RoxA in the absence of heme groups and other characteristics. Notably, Lcp degraded polyisoprene via endo-type cleavage to tetra-C20 and higher oligo-isoprenoids with aldehyde and keto end groups, whereas RoxA used an exo-type cleavage mechanism to give the main end product 12-oxo-4,8-dimethyltrideca-4,8-diene-1-al (ODTD). RoxA was able to cleave isolated Lcp-derived oligo-isoprenoid molecules to ODTD. Inhibitor studies, spectroscopic investigations and metal analysis gave no indication for the presence of iron, other metals, or cofactors in Lcp. Our results suggest that Lcp could be a member of the growing group of cofactor-independent oxygenases and differs in the cleavage mechanism from heme-dependent RoxA. In conclusion, RoxA and Lcp represent two different answers to the same biochemical problem, the cleavage of polyisoprene, a polymer that has carbon-carbon double bonds as the only functional groups for enzymatic attack. PMID:24907333

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

    Directory of Open Access Journals (Sweden)

    Hanbing Liu

    2016-03-01

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

  14. Biorefinery methods for separation of protein and oil fractions from rubber seed kernel

    NARCIS (Netherlands)

    Widyarani, R.; Ratnaningsih, E.; Sanders, J.P.M.; Bruins, M.E.

    2014-01-01

    Biorefinery of rubber seeds can generate additional income for farmers, who already grow rubber trees for latex production. The aim of this study was to find the best method for protein and oil production from rubber seed kernel, with focus on protein recovery. Different pre-treatments and oil

  15. On cavitation, post-cavitation and yield in amorphous polymer-rubber blends

    NARCIS (Netherlands)

    Steenbrink, A.C.; Giessen, E. van der

    1999-01-01

    The deformation behaviour of amorphous polymer-rubber blends is investigated in terms of an axisymmetric unit cell model containing an initially spherical rubber particle. The behaviour of the rubber is described by an incompressible non-Gaussian network theory, while for the matrix we adopt a

  16. 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.

  17. 40 CFR 428.40 - Applicability; description of the latex rubber subcategory.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the latex rubber subcategory. 428.40 Section 428.40 Protection of Environment ENVIRONMENTAL PROTECTION... Rubber Subcategory § 428.40 Applicability; description of the latex rubber subcategory. The provisions of...

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

    Directory of Open Access Journals (Sweden)

    Y. A. Anisimov

    2015-02-01

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

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

    Science.gov (United States)

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

    2016-01-01

    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 contents had been investigated. Finally, the crumb rubber after pretreatment by six modifiers was introduced into the concrete mixture. Corresponding tests were conducted to verify the effectiveness of pretreatment methods as compared to the concrete containing untreated crumb rubber. It was observed that the mechanical strength of crumb rubber concrete was reduced, while durability was improved with the increasing of crumb rubber content. 20% replacement of fine aggregate and 5% replacement of the total mixture exhibited acceptable properties for practical applications. In addition, the results indicated that the modifiers had a positive impact on the mechanical and durability properties of crumb rubber concrete. It avoided the disadvantage of crumb rubber concrete having lower strength and provides a reference for the production of modified crumb rubber concrete. PMID:28773298

  20. Studies on ethylene-propylene-diene rubber modification by N-chlorothio-N-butyl-benzenesulfonamide

    NARCIS (Netherlands)

    Zhang, Hongmei; Datta, Rabin; Talma, Auke; Noordermeer, Jacobus W.M.

    2009-01-01

    N-Chlorothiosulfonamides have been used to modify ethylene-propylene-diene rubber (EPDM) to enhance the compatibility of EPDM in, e.g., natural rubber (NR)/butadiene rubber (BR)/EPDM blends for ozone resistance. N-Chlorothio-N-butyl-benzenesulfonamide (CTBBS) was selected as a representative for

  1. Morphology of Silica-Reinforced Natural Rubber: Effect of Silane Coupling Agent

    NARCIS (Netherlands)

    Sarkawi, S.S.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2015-01-01

    A good dispersion of silica in a rubber vulcanizate is important as it influences the filler-to-rubber interaction and consequently the final properties. This article presents an investigation into the morphology of silica-reinforced natural rubber (NR) in the presence and absence of a silane

  2. Co-extraction of high-quality RNA and DNA from rubber tree (Hevea ...

    African Journals Online (AJOL)

    DR TONUKARI NYEROVWO

    2012-05-15

    May 15, 2012 ... Amazon basin of South American. More than 98% of commercial source of nature rubber (NR) comes from H. brasiliensis. Today, rubber tree is extensively cultivated in. Southeast Asia, where it covers more than 90% of the world's nature rubber production (Priyadarshan and. Goncalves, 2003). Due to the ...

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

    Science.gov (United States)

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

    2016-03-07

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

  4. Preparation of magnetic rubber with high mechanical properties by latex compounding method

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Chunlin [Shanxi Province Key Laboratory of Functional Nanocomposites, North University of China, Taiyuan 030051 (China); College of Materials Science and Engineering, North University of China, Taiyuan 030051 (China); Gao, Li; Yu, Hailing [Shanxi Province Key Laboratory of Functional Nanocomposites, North University of China, Taiyuan 030051 (China); Sun, Youyi, E-mail: syyi@pku.edu.cn [Shanxi Province Key Laboratory of Functional Nanocomposites, North University of China, Taiyuan 030051 (China); College of Materials Science and Engineering, North University of China, Taiyuan 030051 (China); Yao, Junru; Zhao, Guizhe [Shanxi Province Key Laboratory of Functional Nanocomposites, North University of China, Taiyuan 030051 (China); Liu, Yaqing, E-mail: lyqzgz2010@163.com [Shanxi Province Key Laboratory of Functional Nanocomposites, North University of China, Taiyuan 030051 (China); College of Materials Science and Engineering, North University of China, Taiyuan 030051 (China)

    2016-06-01

    the magnetic rubber based on Fe{sub 3}O{sub 4} nanoparticles and nature rubber were prepared by latex compounding method, in which stable Fe{sub 3}O{sub 4} aqueous solutions were mixed with natural rubber latex and additives. This process was fast, versatile, reliable, safe, environmentally friendly and inexpensive. What’s more, it was found that the magnetic and mechanical properties of magnetic rubber increased together with increase in doping content of Fe{sub 3}O{sub 4} nanoparticles. Especially, it was demonstrated that the tensile strength (25.0 Mpa) of magnetic rubber was improved to be 478.0% comparing to neat natural rubber (5.2 Mpa), which was 5 times higher than maximal value reported in previous work. At the same time, the magnetic rubber revealed better thermal stability and solvent resistance comparing to the neat natural rubber, too. The work dose not only provides a new way to environmentally friendly preparation of magnetic rubber at low temperature, but also improve the mechanical and magnetic properties of magnetic rubber applied in industry. - Highlights: • The magnetic rubber was prepared by a latex compounding method. • The magnetic rubber exhibited high mechanical properties. • The mechanism of high mechanical properties was investigated by the NMR.

  5. 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. ...

  6. 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...

  7. No consistent cooling of the real hand in the rubber hand illusion

    NARCIS (Netherlands)

    de Haan, Alyanne M; Van Stralen, Haike E; Smit, Miranda; Keizer, Anouk; Van der Stigchel, Stefan; Dijkerman, H Chris

    In the rubber hand illusion (RHI), participants view a rubber hand that is stroked synchronously with their real, hidden hand. This procedure results in experiencing an increased sense of ownership over the rubber hand and demonstrates how multisensory information (vision, touch) can influence the

  8. Toughness of natural rubber composites reinforced with hydrolyzed and modified wheat gluten aggregates

    Science.gov (United States)

    The toughness of natural rubber can be improved by using fillers for various rubber applications. Dry wheat gluten is a protein from wheat flour and is sufficiently rigid for rubber reinforcement. The wheat gluten was hydrolyzed to reduce its particle size and microfluidized to reduce and homogenize...

  9. Evaluation of bitumen-rubber asphalt manufactured from modified binder at lower viscosity

    CSIR Research Space (South Africa)

    O'Connell, Johannes S

    2010-08-01

    Full Text Available ', the viscosity of the bitumen-rubber binder inevitably falls below the minimum specification, and such binder is contractually unacceptable for use. A bitumen rubber asphalt mix was manufactured using a single aggregate grading and bitumen-rubber binder...

  10. The Blue Revolution in Asia

    DEFF Research Database (Denmark)

    Ponte, Stefano; Kelling, Ingrid; Jespersen, Karen Sau

    2014-01-01

    In this article, we examine the upgrading trajectories of selected aquaculture value chains in four Asian countries and the links between upgrading and three factors of value chain governance: coordination mechanisms; types of drivers; and domestic regulation. We find instances of improving produ...... of upgrading the "blue revolution" in Asia...

  11. Blue Ocean vs. Five Forces

    NARCIS (Netherlands)

    A.E. Burke (Andrew); A.J. van Stel (André); A.R. 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

  12. Mobilizing investors for blue growth

    NARCIS (Netherlands)

    Burg, van den Sander W.K.; Stuiver, Marian; Bolman, Bas C.; Wijnen, Roland; Selnes, Trond; Dalton, Gordon

    2017-01-01

    The European Union's Blue Growth Strategy is a long term strategy to support sustainable growth in the marine and maritime sectors, aiming to contribute to innovation and economic growth (European Commission, 2012). The EU sees the financial sector as a key partner to bring about transition to

  13. Nobel Prize for blue LEDs

    International Nuclear Information System (INIS)

    Kraftmakher, Yaakov

    2015-01-01

    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. (paper)

  14. 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.

  15. 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.

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

    International Nuclear Information System (INIS)

    Lugao, A.B.; Miranda, A.; Mindrisz, A.C.; Andrade e Silva, L.G. de

    1996-01-01

    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

  17. Studies on Properties of Short Fiber Reinforced Natural Rubber Composites

    Directory of Open Access Journals (Sweden)

    M.H.R. Ghoreishy

    2008-12-01

    Full Text Available Natural rubber/fiber composites were prepared in a laboratory mixer using new and waste short nylon fiber by a one-step mixing process. Fiber loading and bonding agent effects on the microstructure and mechanical properties of the composites were studied. The cure characteristics of composites were investigated by using rheometer. Cure and scorching times of the composites decreased while maximum torques increased with increasing fiber loading. The mechanical properties of the composites improved with increasing the short fibers. The adhesion between the fiber and the rubber was enhanced by the addition of a dry bonding system consisting of resorcinol, hexamethylene tetramine and hydrated silica (HRH.

  18. FE Prediction of Hysteretic Component of Rubber Friction

    OpenAIRE

    L. Pálfi; T. Goda; K. Váradi; E. Garbayo; J. M. Bielsa; M. A. Jiménez

    2012-01-01

    The hysteretic part of the friction coefficient for rubber sliding on an ideal rigid, rough surface has been investigated by FE technique. The FE models were created by using two different FE softwares, ABAQUS and MSC.MARC. The surface roughness has been considered by using two different sine waves having a wavelength of 100 μm and 11.11 μm, as well as their superposition. Parameters of the viscoelastic material models of the rubber were gained, firstly from a fit to the measured storage modu...

  19. Radiation processing of natural rubber and its applications

    International Nuclear Information System (INIS)

    Dahlan Hj. Mohd

    2007-01-01

    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)

  20. 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...

  1. DEB-silicone rubber hydrogen absorbing Raman detection technology research

    International Nuclear Information System (INIS)

    Yang Suolong; Zhong Jingrong; Wang Huang; Yang Kaixu; Xiao Jiqun; Liu Jiaxi; Liao Junsheng

    2012-01-01

    The DEB-Pd/C hydrogen getter powder and DEB-Pd/C-silicone rubber getter film were prepared and used for hydrogen detection in close systems by laser Raman method. The DEB alkanes Raman peak intensity changes with the getter time were monitored by Raman spectrometer. As a result, silicone rubber has good compatibility with DEB getter, slow access to hydrogen and good flexible. The alkanes peak intensity-getter time followed a exponential rule. DEB getter films are suitable for Raman on-line monitor of cumulative hydrogen of a closed system at long time. (authors)

  2. Epoxidation of polybutadiene rubber in non polar solvent

    International Nuclear Information System (INIS)

    Schneider, Luciane K. de A.; Jacobi, Marly A.M.

    2005-01-01

    The epoxidation of polybutadiene rubber in cyclohexane, at 50 deg C, by the method of performic acid generated in situ, at different reagent concentration was investigated. The epoxy degree was determined by 1 H-RMN, and because of the gelation and coagulation of modified rubber during the reaction, only a maximum of 30 mol % of epoxy degree could be achieved. The reaction followed a first order kinetic in relation to hydrogen peroxide and acid concentration showing a rate constant of 4,0 (± 0,5) x 10 -5 L.mol-1.seg -1 . (author)

  3. Complex processing of rubber waste through energy recovery

    Directory of Open Access Journals (Sweden)

    Roman Smelík

    2015-12-01

    Full Text Available 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 process is also the separation of metals, which can be returned to the metallurgical secondary production.

  4. 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.

  5. 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)

  6. 21 CFR 133.106 - Blue cheese.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Blue cheese. 133.106 Section 133.106 Food and... CONSUMPTION CHEESES AND RELATED CHEESE PRODUCTS Requirements for Specific Standardized Cheese and Related Products § 133.106 Blue cheese. (a) Description. (1) Blue cheese is the food prepared by the procedure set...

  7. Biolubricant induced phase inversion and superhydrophobicity in rubber-toughened biopolymer/organoclay nanocomposites

    Science.gov (United States)

    Bayer, Ilker S.; Steele, Adam; Martorana, Philip; Loth, Eric; Robinson, Scott J.; Stevenson, Darren

    2009-08-01

    We present a simple technique to fabricate rubber-toughened biopolymer/organoclay nanocomposite coatings with highly water repellent surface wetting characteristics and strong adhesion to metal surfaces. The technique combines the principles of phase inversion and atomization of multicomponent polymer/organoclay suspensions containing a biolubricant as the nonsolvent. The biolubricant was a blend of cyclomethicone/dimethiconol oil with fruit kernel oils. The ternary system of cellulose nitrate/solvent/biolubricant was blended with rubber dispersed organoclay nanofluids. Natural, synthetic, and fluoroacrylic latex rubbers were used for the purpose. Self-cleaning superhydrophobic coatings were obtained from synthetic and fluoroacrylic rubbers whereas natural rubber containing formulations resulted in sticky superhydrophobic coatings.

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

    International Nuclear Information System (INIS)

    Kadima, T.H.

    2011-01-01

    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

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

    DEFF Research Database (Denmark)

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

    1997-01-01

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

  10. Adaptive neuro-fuzzy inference system for forecasting rubber milk production

    Science.gov (United States)

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

    2018-02-01

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

  11. Pengaruh Penggunaan Nitril Butadiene Rubber Dan Pale Crepe Pada Pembuatan Sol Karet Untuk Sepatu Pengaman

    OpenAIRE

    Yuniari, Arum

    2010-01-01

    Rubber sole for safety shoes was different on physical specification with general sole, especially on abrasion resistance and oil resistance. The objective of the study was to determine the effect of nitril butadiene rubber and pale crepe on physical properties of vulcanized rubber sole for safety shoes. Rubber sole for safety shoes was produced by blending pale crepe and nitril butadiene rubber with ratio of : 50/50; 60/40; 70/30 and 80/20 phr, respectively. Carbon black as filler was also v...

  12. Pengaruh penggunaan nitril butadiene rubber dan pale crepe pada pembuatan sol karet untuk sepatu pengaman

    OpenAIRE

    Arum Yuniari

    2010-01-01

    Abstract Rubber sole for safety shoes was different on physical specification with general sole, especially on abrasion resistance and oil resistance. The objective of the study was to determine the effect of nitril butadiene rubber and pale crepe on physical properties of vulcanized rubber sole for safety shoes. Rubber sole for safety shoes was produced by blending pale crepe and nitril butadiene rubber with ratio of : 50/50; 60/40; 70/30 and 80/20 phr, respectively. Carbon black as fill...

  13. 75 FR 65525 - Anthem Blue Cross Blue Shield, Claim Management Services, Inc. Operations, a Division of...

    Science.gov (United States)

    2010-10-25

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-74,327] Anthem Blue Cross Blue Shield, Claim Management Services, Inc. Operations, a Division of Wellpoint, Inc., Green Bay, WI; Notice... former workers of Anthem Blue Cross Blue Shield, Claim Management Services, Inc. Operations, a Division...

  14. 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.

  15. The attitude of Czech dental patients to the use of rubber dam.

    Science.gov (United States)

    Kapitan, Martin; Hodacova, Lenka; Jagelska, Julie; Kaplan, Jiri; Ivancakova, Romana; Sustova, Zdenka

    2015-10-01

    The most frequent arguments against rubber dam are that patients generally do not like it and the prolonged time of treatment. However, according to several studies, the attitude of patients towards rubber dam is rather positive. To find out the attitudes of patients to treatment with rubber dam; to determine influence of the circumstances of treatment or factors about patients; and to establish a mean time needed for rubber dam placement. A questionnaire survey. Patients of general dental practitioners, university clinical specialists and undergraduate dental students. A total of 179 questionnaires were distributed, from which 150 were returned. The mean time needed for rubber dam placement was 4 min for students and dam. A total of 77% of patients indicated a higher level of comfort during treatment with rubber dam. A preference to the future rubber dam usage was indicated by 86% of patients. The preference to the further rubber dam usage was statistically significantly affected by the level of comfort during the treatment with rubber dam (P dam usage (P dam usage. The attitude of patients to rubber dam was rather positive in our study. The time needed for rubber dam application was rather short. © 2013 John Wiley & Sons Ltd.

  16. Temperature dependence of the dielectric properties of rubber wood

    Science.gov (United States)

    Mohammed Firoz Kabir; Wan M. Daud; Kaida B. Khalid; Haji A.A. Sidek

    2001-01-01

    The effect of temperature on the dielectric properties of rubber wood was investigated in three anisotropic directions—longitudinal, radial, and tangential, and at different measurement frequencies. Low frequency measurements were conducted with a dielectric spectrometer, and high frequencies used microwave applied with open-ended coaxial probe sensors. Dielectric...

  17. Dynamic response of fly ash reinforced functionally graded rubber ...

    African Journals Online (AJOL)

    The dynamic analysis of jute-epoxy sandwiches with fly ash reinforced functionally gradient (FG) flexible, compliant rubber core is presented. FG samples are prepared using conventional casting technique. Presence of gradation is quantified by weight method. An attempt is made to study the influence of fly ash weight ...

  18. Characterization of weed flora in rubber trees plantations of Bongo ...

    African Journals Online (AJOL)

    SARAH

    2013-10-31

    Ivoire). 5544. Characterization of weed flora in rubber trees plantations of Bongo (Côte d'Ivoire). TUO Korna F. André1, OREGA Youppo Barthélémy2, KOUAME Koffi Badou Jérémie2, ABO. Kouabenan2, AGNEROH Thérèse ...

  19. adoption of improved rubber production technologies by farmers in ...

    African Journals Online (AJOL)

    PROF. BARTH EKWEME

    1987-09-23

    Sep 23, 1987 ... Campbell (2000), natural rubber became popular in. Europe after the invention of pheumatic tyre for bicycles and cars. The discovery of waterproof garments by ..... The enterprise however was highly profitable and holds a strong prospect for household income generation, export and youth empowerment if ...

  20. High concentrations of natural rubber latex allergens in gloves used ...

    African Journals Online (AJOL)

    Introduction. Gloves made of natural rubber latex (NRL) are commonly used by healthcare workers because of their good qualities. However, allergic reactions to latex allergens are still commonly reported. Objective. To measure the concentrations of Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 allergens in gloves used by a ...

  1. Investigations of surface characterization of silicone rubber due to ...

    Indian Academy of Sciences (India)

    Unknown

    thoroughly understood especially in silicone rubber, as it is used as a best construction material for a.c. applica- tions. A separate experimental methodology has been adapted, to understand the influence of acids on the sur- face condition of the polymeric material and on tracking phenomena. In addition residues formed ...

  2. Rubber contact mechanics: adhesion, friction and leakage of seals.

    Science.gov (United States)

    Tiwari, A; Dorogin, L; Tahir, M; Stöckelhuber, K W; Heinrich, G; Espallargas, N; Persson, B N J

    2017-12-13

    We study the adhesion, friction and leak rate of seals for four different elastomers: Acrylonitrile Butadiene Rubber (NBR), Ethylene Propylene Diene (EPDM), Polyepichlorohydrin (GECO) and Polydimethylsiloxane (PDMS). Adhesion between smooth clean glass balls and all the elastomers is studied both in the dry state and in water. In water, adhesion is observed for the NBR and PDMS elastomers, but not for the EPDM and GECO elastomers, which we attribute to the differences in surface energy and dewetting. The leakage of water is studied with rubber square-ring seals squeezed against sandblasted glass surfaces. Here we observe a strongly non-linear dependence of the leak rate on the water pressure ΔP for the elastomers exhibiting adhesion in water, while the leak rate depends nearly linearly on ΔP for the other elastomers. We attribute the non-linearity to some adhesion-related phenomena, such as dewetting or the (time-dependent) formation of gas bubbles, which blocks fluid flow channels. Finally, rubber friction is studied at low sliding speeds using smooth glass and sandblasted glass as substrates, both in the dry state and in water. The measured friction coefficients are compared to theory, and the origin of the frictional shear stress acting in the area of real contact is discussed. The NBR rubber, which exhibits the strongest adhesion both in the dry state and in water, also shows the highest friction both in the dry state and in water.

  3. Adhesion enhancement for liquid silicone rubber and different ...

    Indian Academy of Sciences (India)

    Abstract. Surface modification of aluminum, glass, epoxy resin, polypropylene and polyethylene via corona dis- charge pretreatment and platinum catalyst addition to promote their adhesion with liquid silicone rubber is reported. The corona-pretreated substrate surface was silanized with vinyltrimethoxysilane to generate ...

  4. Influence of the Diene Monomer on Devulcanization of EPDM Rubber

    NARCIS (Netherlands)

    Verbruggen, M.A.L.; van der Does, L.; Noordermeer, Jacobus W.M.; van Duin, M.

    2008-01-01

    Ethylene–propylene–diene rubbers (EPDM) with 2-ethylidene-5-norbornene (ENB), dicyclopentadiene (DCPD), and 1,4-hexadiene (HD) as third monomers have been vulcanized with peroxide and with a conventional sulfur vulcanization recipe, and their devulcanization was subsequently investigated for

  5. [Preparation of Rubber Accelerator Zinc Diethyldithiocarbamate and Its Spectral Analysis].

    Science.gov (United States)

    Zhang, Zhi-liang; Jia, Tai-xuan; Jiang, Yue-hua; Peng, Hong-yan; Xu, Guang-pu; Li, Hong-liang

    2015-08-01

    In the study, rubber accelerator Zinc diethyldithiocarbamate (EZ) was synthesized firstly. Complex EZ of single crystal was cultivated by solvent evaporation method. EZ was detected and characterized by XRD single crystal diffraction, FTIR and TG-DSC. The micro-structure and intrinsic regularity were revealed. Its highly efficient performance of rubber vulcanization promotion was decided due to its orientation structure? and high order. The result of TG-DSC showed that complex EZ was possessed with a little CS2. The chemical bond types in EZ were revealed by FTIR, the same as single crystal? diffraction testing by different way. The decomposition temperature of EZ was very high. It could provided reference with research on rubber vulcanizing properties by EZ on rubber vulcanizing machine. This study can help the enterprises to designate the working standard tracing detection of EZ industrialized production. Performance index of EZ was judged. The project of EZ industry standard can be declared by the enterprises, written a draft standard on the basis experimental data.

  6. The challenges of silica-silane reinforcement of natural rubber

    NARCIS (Netherlands)

    Dierkes, Wilma K.; Sarkawi, S.S.; Noordermeer, Jacobus W.M.

    2012-01-01

    In recent years, highly-dispersible silica has become the preferred alternative to carbon-black as reinforcing filler for low rolling-resistance tires. However, the application of this filler system is so far limited to passenger car tires, as their treads contain styrene butadiene rubber (SBR). In

  7. 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

  8. Investigations of surface characterization of silicone rubber due to ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. In the present work, tracking phenomena has been studied with silicone rubber material under the. a.c. and d.c. voltages following IEC-587 standards. The surface condition of the tracked zone was analysed using wide angle X-ray diffraction (WAXD) and thermogravimetric differential thermal analysis (TG–DTA).

  9. Economic Analysis of Intercropping Rubber (Hevea brasiliensis) in ...

    African Journals Online (AJOL)

    Mr D.Y. Giroh

    rubber-based intercrop for 2007 / 2008 planting season. Data analysis: Data collected were analyzed using descriptive statistics, budgetary technique and the production function analysis. Four functional forms (linear, semi-log, exponential and power function) were fitted to the data. Exponential function gave the best fit and ...

  10. Marine bacterial prodigiosin as dye for rubber latex, polymethyl ...

    African Journals Online (AJOL)

    Prodigiosin is known for its immunomodulatory, antibacterial, antimycotic, antimalarial, algicidal and anticancer activities. Here, we reported the evaluation of prodigiosin pigment as a dyeing agent in rubber latex, paper and polymethyl methacrylate (PMMA) so that it can be considered as an alternative to synthetic pigments.

  11. Application of methylol urea/natural rubber copolymer composite for ...

    African Journals Online (AJOL)

    This work is a follow up to our quest to develop emulsion paint from amino resin. Both pure urea methylol (MU) and methylol urea/Nature rubber (MU/NR) blend were prepared. Some physico-chemical properties such as viscosity, melting point, moisture uptake, refractive index, density, elongation at break and formaldehyde ...

  12. Biobased products from rubber, jatropha and sunflower oil

    NARCIS (Netherlands)

    Bin Abu Ghazali, Yusuf

    2015-01-01

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

  13. Experience with rubber band ligation of hemorrhoids in northern ...

    African Journals Online (AJOL)

    Background: Treatment of hemorrhoids in Nigeria is usually done by the traditional open method that requires hospital admission; anesthesia and is associated with high morbidity. Rubber band ligation is a suitable alternative to open hemorrhoidectomy and has the potential to reduce the need for hospital admission.

  14. Rubber composites cured with sulphur and peroxide and ...

    Indian Academy of Sciences (India)

    ... KRUŽELÁK1 RASTISLAV DOSOUDIL2 RICHARD SÝKORA1 IVAN HUDEC1. Department of Plastics and Rubber, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava, Slovakia; Department of Electromagnetic Theory, Faculty of Electrical Engineering and Information Technology, ...

  15. Tailoring magnetic and dielectric properties of rubber ferrite ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Rubber ferrite composites containing various mixed ferrites were prepared for different compositions and various loadings. The magnetic and dielectric properties of the fillers as well as the ferrite filled matrixes were evaluated separately. The results are correlated. Simple equations are proposed to predetermine ...

  16. No Pain Relief with the Rubber Hand Illusion

    Science.gov (United States)

    Petkova, Valeria I.; Dey, Abishikta; Barnsley, Nadia; Ingvar, Martin; McAuley, James H.; Moseley, G. Lorimer; Ehrsson, Henrik H.

    2012-01-01

    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 (pillusion does not induce analgesia. PMID:23285026

  17. Linear motion feed through with thin wall rubber sealing element

    Science.gov (United States)

    Mikhailov, V. P.; Deulin, E. A.

    2017-07-01

    The patented linear motion feedthrough is based on elastic thin rubber walls usage being reinforced with analeptic string fixed in the middle part of the walls. The pneumatic or hydro actuators create linear movement of stock. The length of this movement is two times more the rubber wall length. This flexible wall is a sealing element of feedthrough. The main advantage of device is negligible resistance force that is less then mentioned one in sealing bellows that leads to positioning error decreasing. Nevertheless, the thin wall rubber sealing element (TRE) of the feedthrough is the main unreliable element that was the reason of this element longevity research. The theory and experimental results help to create equation for TRE longevity calculation under vacuum or extra high pressure difference action. The equation was used for TRE longevity determination for hydraulic or vacuum equipment realization also as it helps for gas flow being leaking through the cracks in thin walls of rubber sealing element of linear motion feedthrough calculation.

  18. Small scale industrial application of rubber seed oil in soap ...

    African Journals Online (AJOL)

    The oil, which was extracted from the rubber seed using the mechanical pressing method, was of high acid value, that is, the free fatty acid content is high and the oil is not edible, with an average saponification value. Its pH was slightly basic which makes it suitable for use in soap manufacture. It was, therefore, used as a ...

  19. Another Demo of the Unusual Thermal Properties of Rubber

    Science.gov (United States)

    Liff, Mark I.

    2010-01-01

    The unusual thermal behavior of rubbers, though discovered a long time ago, can still be mind-boggling for students and teachers who encounter this class of polymeric systems. Unlike other solids, stretched elastic polymers shrink upon heating. This is a manifestation of the Gough-Joule (G-J) effect. Joule in the 1850s studied the thermal behavior…

  20. Application of Recycled Rubber from Scrap Tyres in the Adsorption ...

    African Journals Online (AJOL)

    The adsorption of toluene from aqueous solution using waste tyre rubber granules (WTRG) was investigated in a batch system. The effect of various factors such as contact time, amount of adsorbent, size of adsorbent particles, and temperature of solution on the adsorption capacity of WTRG was determined.

  1. Cutting height effects on guayule latex, rubber and resin yields

    Science.gov (United States)

    Guayule (Parthenium argentatum Gray) is a perennial shrub native to the Chihuahuan Desert. While guayule traditionally has been cultivated for rubber, more recently it is being cultivated for its hypoallergenic latex. Other uses including termite resistant wood products and as an energy source have ...

  2. Tribological behavior of W-DLC coated rubber seals

    NARCIS (Netherlands)

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

    2008-01-01

    Tungsten-containing diamond-like carbon (W-DLC) coatings have been deposited on FKM (fluorocarbon) and HNBR (hydrogenated nitrile butadiene) rubbers via unbalanced magnetron reactive sputtering from a WC target in a C2H2/Ar plasma. The surface morphology and fracture cross sections of uncoated and

  3. Adoption of improved rubber production technologies by farmers in ...

    African Journals Online (AJOL)

    Adoption of improved rubber production technologies by farmers in Akwa Ibom state, Nigeria. ... Global Journal of Agricultural Sciences ... Primary data generated from the survey were analyzed using descriptive statistics such as percentages, frequencies, averages, paired t-test analysis and grading scale models.

  4. 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…

  5. Modelling of static friction in rubber-metal contact

    NARCIS (Netherlands)

    Deladi, E.L.; de Rooij, Matthias B.; Schipper, Dirk J.

    2007-01-01

    A static friction model for contact between rough rubber and metal surfaces is developed. This model is based on the contact of a viscoelastic–rigid asperity couple. Single asperity contact is modelled in such a way that the asperities stick together in a central region and slip over an annulus at

  6. Static friction of stainless steel wire rope–rubber contacts.

    NARCIS (Netherlands)

    Loeve, A.J.; Krijger, T.; Mugge, W.; Breedveld, P.; Dodou, D.; Dankelman, J.

    2014-01-01

    Little is known about static friction of stainless-steel wire ropes ('cables') in contact with soft rubbers, an interface of potential importance for rigidifiable medical instruments. Although friction theories imply that the size and profile of the cables affect static friction, there are no

  7. 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.

  8. Rubber composites cured with sulphur and peroxide and ...

    Indian Academy of Sciences (India)

    2Department of Electromagnetic Theory, Faculty of Electrical Engineering and Information Technology, Slovak. University of Technology, 812 19 Bratislava, Slovakia. MS received 18 March 2016; accepted 30 May 2016. Abstract. In the present work, rubber magnetic composites were prepared by incorporation of strontium ...

  9. Positron Annihilation in a Rubber Modified Epoxy Resin

    DEFF Research Database (Denmark)

    Mogensen, O. E.; Jacobsen, F. M.; Pethrick, R. A.

    1979-01-01

    Positron annihilation data is reported on a rubber-modified epoxy resin. Studies of the temperature dependence of the o-positronium lifetime indicated the existence of three distinct regions; the associated transition temperatures by comparison with dilatometric data can be ascribed respectively...

  10. comparative analysis of rubber seed methyl ester with other methyl ...

    African Journals Online (AJOL)

    DJFLEX

    (2004). The RSO oil is heated to about 60oC and the mixture is stirred at the speed of 360 rpm. The temperature range of 50 – 60oC is maintained during this experiment. RESULTS AND DISCUSSION. The fatty acid composition and the important properties of rubber seed oil in comparison with other oils is given in Table 1.

  11. Nanocomposites of natural rubber and polyaniline-modified cellulose nanofibrils

    Science.gov (United States)

    Cellulose nanofibrils (CNF) were isolated from cotton microfibrils (CM) by acid hydrolysis and coated with polyaniline (PANI) by in situ polymerization of aniline onto CNF in the presence of hydrochloride acid and ammonium peroxydisulfate to produce CNF/PANI. Nanocomposites of natural rubber (NR) re...

  12. Numerical Modelling of Rubber Vibration Isolators: identification of material parameters

    NARCIS (Netherlands)

    Beijers, C.A.J.; Noordman, Bram; de Boer, Andries; Ivanov, N.I.; Crocker, M.J.

    2004-01-01

    Rubber vibration isolators are used for vibration isolation of engines at high frequencies. To make a good prediction regarding the characteristics of a vibration isolator in the design process, numerical models can be used. However, for a reliable prediction of the dynamic behavior of the isolator,

  13. Tailoring magnetic and dielectric properties of rubber ferrite ...

    Indian Academy of Sciences (India)

    Unknown

    Safari Ardi M, Dick W and McQueen D H 1995 Plastics,. Rubber and Composites – Processing and Applications 24 157. Soshin Chikazumi 1964 Physics of magnetism (New York: John. Wiley & Sons Inc.) Smit J and Wijn H P G 1959 Ferrites (The Netherlands: Phillips. Technical Library). Sung Soo Kim and Dae Hee Han ...

  14. The Physics of the Blues

    Science.gov (United States)

    Gibson, J. Murray

    2009-03-01

    In looking at the commonalities between music and science, one sees that the musician's palette is based on the principles of physics. The pitch of a musical note is determined by the frequency of the sound wave. The scales that musicians use to create and play music can be viewed as a set of rules. What makes music interesting is how musicians develop those rules and create ambiguity with them. I will discuss the evolution of western musical scales in this context. As a particular example, ``Blue'' notes are very harmonic notes that are missing from the equal temperament scale. The techniques of piano blues and jazz represent the melding of African and Western music into something totally new and exciting. Live keyboard demonstrations will be used. Beyond any redeeming entertainment value the talk will emphasize the serious connections between science and art in music. Nevertheless tips will be accepted.

  15. Thermoluminescence (TL) of Egyptian Blue

    Energy Technology Data Exchange (ETDEWEB)

    Schvoerer, M.; Delavergne, M.-C.; Chapoulie, R.

    1988-01-01

    Egyptian Blue is a synthesized crystalline pictorial pigment with formula CaCuSi/sub 4/O/sub 10/. It has been used in Egypt and Mesopotamia from the 3rd millenium B.C. A preliminary experiment on a recently synthesized sample showed that this pigment is thermoluminescent after ..beta.. irradiation (/sup 90/Sr). As the signal intensity grows linearly with the administered dose within the temperature range commonly used in TL dating, we have been looking for this phenomenon from archaeological pigments. It was encountered with two samples found in excavation. From its intensity and stability we concluded that Egyptian Blue can be dated using TL. This first and positive result encouraged us to extend the method to other types of mineral pigments synthesized by early man, and to suggest that it may be used for direct dating of ancient murals.

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

    Directory of Open Access Journals (Sweden)

    Gang Xue

    2017-01-01

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

  17. 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.

  18. 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.

  19. Cumulative Effect of Crumb Rubber and Steel Fiber on the Flexural Toughness of Concrete

    Directory of Open Access Journals (Sweden)

    B. H. Abu Bakar

    2017-02-01

    Full Text Available Concrete properties, such as toughness and ductility, are enhanced to resist different impacts or blast loads. Rubberized concrete, which could be considered a green material, is produced from recycled waste tires grinded into different crumb rubber particle sizes and mixed with concrete. In this study, the behavior of rubberized steel fiber-reinforced concrete is investigated. Flexural performance of concrete beams (400×100×100 mm manufactured from plain, steel fiber, crumb rubber and combination crumb rubber and steel fiber are also evaluated. Similarly, concrete slabs (500×500×50 mm are also tested under flexural loading. Flexural performance of the SFRRC mixtures was significantly enhanced. The toughness and maximum deflection of specimens with rubber were considerably improved. Steel fiber/crumb rubber-reinforced concrete can be used for practical application, which requires further studies.

  20. 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.

  1. Blue breath holding is benign.

    OpenAIRE

    Stephenson, J B

    1991-01-01

    In their recent publication in this journal, Southall et al described typical cyanotic breath holding spells, both in otherwise healthy children and in those with brainstem lesions and other malformations. Their suggestions regarding possible autonomic disturbances may require further study, but they have adduced no scientific evidence to contradict the accepted view that in the intact child blue breath holding spells are benign. Those families in which an infant suffers an 'apparently life t...

  2. Galaxies on the Blue Edge

    OpenAIRE

    Cabanela, J. E.; Dickey, J. M.

    2002-01-01

    We have successfully constructed a catalog of HI-rich galaxies selected from the Minnesota Automated Plate Scanner Catalog of the Palomar Observatory Sky Survey (POSS I) based solely on optical criteria. We identify HI-rich candidates by selecting the bluest galaxies at a given apparent magnitude, those galaxies on the "blue edge" of POSS I color-magnitude parameter space. Subsequent 21-cm observations on the upgraded Arecibo 305m dish detected over 50% of the observed candidates. The detecte...

  3. Blue light regulated shade avoidance.

    Science.gov (United States)

    Keuskamp, Diederik H; Keller, Mercedes M; Ballaré, Carlos L; Pierik, Ronald

    2012-04-01

    Most plants grow in dense vegetation with the risk of being out-competed by neighboring plants. These neighbors can be detected not only through the depletion in light quantity that they cause, but also through the change in light quality, which plants perceive using specific photoreceptors. Both the reduction of the red:far-red ratio and the depletion of blue light are signals that induce a set of phenotypic traits, such as shoot elongation and leaf hyponasty, which increase the likelihood of light capture in dense plant stands. This set of phenotypic responses are part of the so called shade avoidance syndrome (SAS). This addendum discusses recent findings on the regulation of the SAS of Arabidopsis thaliana upon blue light depletion. Keller et al. and Keuskamp et al. show that the low blue light attenuation induced shade avoidance response of seedling and rosette-stage A. thaliana plants differ in their hormonal regulation. These studies also show there is a regulatory overlap with the R:FR-regulated SAS.

  4. Comparative proteome analysis of rubber latex serum from pathogenic fungi tolerant and susceptible rubber tree (Hevea brasiliensis).

    Science.gov (United States)

    Havanapan, Phattara-Orn; Bourchookarn, Apichai; Ketterman, Albert J; Krittanai, Chartchai

    2016-01-10

    Many cultivated rubber trees (Hevea brasiliensis) are invaded by various Phytophthora species fungi, especially in tropical regions which result in crop yield losses. Comparative proteome analysis coupled with liquid chromatography electrospray/ionization (LC-ESI) mass spectrometry identification was employed to investigate the relative abundance of defense related proteins in Phytophthora sp. susceptible (RRIM600) and tolerant (BPM24) clones of rubber tree. Proteome maps of non-rubber constituent of these two model clones show similar protein counts, although some proteins show significant alterations in their abundance. Most of the differentially abundant proteins found in the serum of BPM24 illustrate the accumulation of defense related proteins that participate in plant defense mechanisms such as beta-1,3-glucanase, chitinase, and lectin. SDS-PAGE and 2-D Western blot analysis showed greater level of accumulation of beta-1,3-glucanase and chitinase in latex serum of BPM24 when compared to RRIM600. A functional study of these two enzymes showed that BPM24 serum had greater beta-1,3-glucanase and chitinase activities than that of RRIM600. These up-regulated proteins are constitutively expressed and would serve to protect the rubber tree BPM24 from any fungal invader. The information obtained from this work is valuable for understanding of defense mechanisms and plantation improvement of H. brasiliensis. Non-rubber constituents (latex serum) have almost no value and are treated as waste in the rubber agricultural industry. However, the serum of natural rubber latex contains biochemical substances. The comparative proteomics analysis of latex serum between tolerant and susceptible clones reveals that the tolerant BPM24 clone contained a high abundance of several classes of fungal pathogen-responsive proteins, such as glucanase and chitinase. Moreover, other proteins identified highlighted the accumulation of defensive-associated proteins participating in plant

  5. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles

    Directory of Open Access Journals (Sweden)

    Solairaj Dhananasekaran

    2016-01-01

    Full Text Available Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB, Bromophenol Blue (BPB and Coomassie Brilliant Blue (CBB by α-chitin nanoparticles (CNP prepared from Penaeus monodon (Fabricius, 1798 shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R2 values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes and pseudo second order kinetics (R2 values were 0.996, 0.999 and 0.996 for MB, BPB and CBB more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents.

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

    Directory of Open Access Journals (Sweden)

    Weili Kou

    2015-01-01

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

  7. Responses of rubber leaf phenology to climatic variations in Southwest China.

    Science.gov (United States)

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

    2017-11-13

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

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

    Science.gov (United States)

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

    2017-11-01

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

  9. Responses of rubber leaf phenology to climatic variations in Southwest China

    Science.gov (United States)

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

    2017-11-01

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

  10. SOLUTION TO THE PROBLEM WASTE RUBBER PRODUCTS BY MODIFYING THE ROAD BINDERS

    Directory of Open Access Journals (Sweden)

    P. S. Beliaev

    2014-01-01

    Full Text Available Summary. The article considers the problem of waste rubber industry through their recycling, compelling stakeholders to keep stocks of valuable raw rubber and improve our environment. The questions of the processes of thermal devulcanization of rubber crumb rubber products, and then use the resulting material (reclaimed rubber crumb as a modifier to improve the quality of road binder. The effect of technological parameters devulcanisation thermal (temperature and exposure time on the degree of devulcanization of crumb rubber. The question of the choice of environmentally friendly agents and emollients devulcanisation to speed the process flow. Researches modifications road binder Reclaimed rubber crumbs obtained under different conditions. The degree of influence of the content of reclaimed rubber crumb on the physico-mechanical properties of road binder bitumen BND 60/90. Studies have shown that the physical and mechanical properties of modified bitumen conform to standards of rubber bitumen binders in accordance with the recommendations of the firm "BITREK": introduction regeneration rata crumb rubber binder in the road leads to an increase in the softening temperature and the appearance of elasticity in the binder compared to the original bitumen and the values of penetration and elongation are within acceptable limits. Thus, the use of recycled materials, reduces the cost of producing a binder for pavement compared to peers.

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

    Science.gov (United States)

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

    2008-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Chrysochoos A.

    2010-06-01

    Full Text Available Owing to their high molecular mobility, stressed rubber chains can easily change their conformations and get orientated. This phenomena leads to so high reversible draw ratio that this behaviour is called rubber elasticity [1-3]. The analogy with ideal gases leads to an internal energy independent of elongation, the stress being attributed to a so-called configuration entropy. However, this analysis cannot take thermal expansion into account and moreover prohibits predicting standard thermo-elastic effect noticed at small elongations and the thermoelastic inversion effects [4]. This paper aims at : observing and quantifying dissipative and coupling effects associated with deformation energy, generated when Natural Rubber is stretched. re-examine the thermomechanical behaviour model of rubberlike materials, under the generalised standard material concept. From an experimental viewpoint, energy balance is created using infrared and quantitative imaging techniques. Digital Image Correlation (DIC provides in-the-plane displacement fields and, after derivation, strain and strain-rate fields. We have used those techniques to evidence the thermoelastic inversion effect as shown on Figure 1 where different weights have been fixed to warmed specimen and we monitored the sample deformation while it recovers room temperature. But we have also used those techniques to perform energy balance : analysis of the mechanical equilibrium allows estimates of the stress pattern and computation of deformation energy rates under a plane stress hypothesis [5]. Infrared Thermography (IRT gives the surface temperature of the sample. To estimate the distribution of heat sources, image processing with a local heat equation and a minimal set of approximation functions (image filtering was used. The time courses of deformation energy and heat associated with cyclic process are plotted in Figure 2. The time derivatives of both forms of energy are approximately similar. This

  13. Numerical simulations of rubber bearing tests and shaking table tests

    International Nuclear Information System (INIS)

    Hirata, K.; Matsuda, A.; Yabana, S.

    2002-01-01

    Test data concerning rubber bearing tests and shaking table tests of base-isolated model conducted by CRIEPI are provided to the participants of Coordinated Research Program (CRP) on 'Intercomparison of Analysis Methods for predicting the behaviour of Seismically Isolated Nuclear Structure', which is organized by International Atomic Energy Agency (IAEA), for the comparison study of numerical simulation of base-isolated structure. In this paper outlines of the test data provided and the numerical simulations of bearing tests and shaking table tests are described. Using computer code ABAQUS, numerical simulations of rubber bearing tests are conducted for NRBs, LRBs (data provided by CRIEPI) and for HDRs (data provided by ENEA/ENEL and KAERI). Several strain energy functions are specified according to the rubber material test corresponding to each rubber bearing. As for lead plug material in LRB, mechanical characteristics are reevaluated and are made use of. Simulation results for these rubber bearings show satisfactory agreement with the test results. Shaking table test conducted by CRIEPI is of a base isolated rigid mass supported by LRB. Acceleration time histories, displacement time histories of the isolators as well as cyclic loading test data of the LRB used for the shaking table test are provided to the participants of the CRP. Simulations of shaking table tests are conducted for this rigid mass, and also for the steel frame model which is conducted by ENEL/ENEA. In the simulation of the rigid mass model test, where LRBs are used, isolators are modeled either by bilinear model or polylinear model. In both cases of modeling of isolators, simulation results show good agreement with the test results. In the case of the steel frame model, where HDRs are used as isolators, bilinear model and polylinear model are also used for modeling isolators. The response of the model is simulated comparatively well in the low frequency range of the floor response, however, in

  14. Thermomyces lanuginosus STm: a source of thermostable hydrolytic enzymes for novel application in extraction of high-quality natural rubber from Taraxacum kok-saghyz (rubber dandelion)

    Science.gov (United States)

    Hydrolytic enzymes from a newly isolated strain of the thermophilic fungus Thermomyces lanuginosus were used to extract rubber from Taraxacum kok-saghyz commonly known as rubber (or Russian or Kazak(h)) dandelion. The fungus was isolated from garden soil and identified as Thermomyces lanuginosus STm...

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

    NARCIS (Netherlands)

    Guo, R.

    2009-01-01

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

  16. Polypropylene-rubber blends 4: the effect of the rubber particle size on the fracture behaviour at low and high test speed

    NARCIS (Netherlands)

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

    1999-01-01

    The effect of the rubber particle size and rubber content on the fracture behaviour of polypropylene–EPR blends was studied at low and high test speeds. The particle size was varied by changing the molecular weight of the EPR phase, and ranged from about 0.5 to around 4.0 μm. The fracture behaviour

  17. Blue breath holding is benign.

    Science.gov (United States)

    Stephenson, J B

    1991-01-01

    In their recent publication in this journal, Southall et al described typical cyanotic breath holding spells, both in otherwise healthy children and in those with brainstem lesions and other malformations. Their suggestions regarding possible autonomic disturbances may require further study, but they have adduced no scientific evidence to contradict the accepted view that in the intact child blue breath holding spells are benign. Those families in which an infant suffers an 'apparently life threatening event' deserve immense understanding and help, and it behoves investigators to exercise extreme care and self criticism in the presentation of new knowledge which may bear upon their management and their morale. PMID:2001115

  18. Investigation of Mechanical Properties of Magneto-Rheological Ethylene Propylene Diene Monomer and Natural Rubber Type Synthetic Rubbers for Both Isotropic and Anisotropic Situations

    Directory of Open Access Journals (Sweden)

    Uğur Mazlum

    2015-12-01

    Full Text Available Magneto-rheological (MR materials are in a smart material class that has the rheological properties to be quickly and reversibly controlled with the external magnetic field applications. Considering the technological developments the rubber-like smart materials has had a more functional usage area with magneto- rheological effect. This study investigates the axial mechanical properties of magneto-rheological Ethylene Propylene Diene Monomer (EPDM and Natural Rubber (NR type synthetic rubbers for isotropic and anisotropic situations. Also, these composite materials were built by means of hot press systems as either isotropic or anisotropic using magnetic field application after addition of ferromagnetic powders. The influence of magnetic field was investigated. In this study, NR rubber was found to be more susceptible in terms of smart material properties unlike EPDM synthetic rubber.

  19. Micro-organisms in latex and natural rubber coagula of Hevea brasiliensis and their impact on rubber composition, structure and properties.

    Science.gov (United States)

    Salomez, M; Subileau, M; Intapun, J; Bonfils, F; Sainte-Beuve, J; Vaysse, L; Dubreucq, E

    2014-10-01

    Natural rubber, produced by coagulation of the latex from the tree Hevea brasiliensis, is an important biopolymer used in many applications for its outstanding properties. Besides polyisoprene, latex is rich in many nonisoprene components such as carbohydrates, proteins and lipids and thereby constitutes a favourable medium for the development of micro-organisms. The fresh rubber coagula obtained by latex coagulation are not immediately processed, allowing the development of various microbial communities. The time period between tree tapping and coagula processing is called maturation, during which an evolution of the properties of the corresponding dry natural rubber occurs. This evolution is partly related to the activity of micro-organisms and to the modification of the biochemical composition. This review synthesizes the current knowledge on microbial populations in latex and natural rubber coagula of H. brasiliensis and the changes they induce on the biochemistry and technical properties of natural rubber during maturation. © 2014 The Society for Applied Microbiology.

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

    Directory of Open Access Journals (Sweden)

    Salni Salni

    2017-06-01

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

  1. Electronic properties of blue phosphorene/graphene and blue phosphorene/graphene-like gallium nitride heterostructures.

    Science.gov (United States)

    Sun, Minglei; Chou, Jyh-Pin; Yu, Jin; Tang, Wencheng

    2017-07-05

    Blue phosphorene (BlueP) is a graphene-like phosphorus nanosheet which was synthesized very recently for the first time [Nano Lett., 2016, 16, 4903-4908]. The combination of electronic properties of two different two-dimensional materials in an ultrathin van der Waals (vdW) vertical heterostructure has been proved to be an effective approach to the design of novel electronic and optoelectronic devices. Therefore, we used density functional theory to investigate the structural and electronic properties of two BlueP-based heterostructures - BlueP/graphene (BlueP/G) and BlueP/graphene-like gallium nitride (BlueP/g-GaN). Our results showed that the semiconducting nature of BlueP and the Dirac cone of G are well preserved in the BlueP/G vdW heterostructure. Moreover, by applying a perpendicular electric field, it is possible to tune the position of the Dirac cone of G with respect to the band edge of BlueP, resulting in the ability to control the Schottky barrier height. For the BlueP/g-GaN vdW heterostructure, BlueP forms an interface with g-GaN with a type-II band alignment, which is a promising feature for unipolar electronic device applications. Furthermore, we discovered that both G and g-GaN can be used as an active layer for BlueP to facilitate charge injection and enhance the device performance.

  2. Popping balloons: formation of a crack network in rubber membranes

    Science.gov (United States)

    Moulinet, Sebastien; Adda-Bedia, Mokhtar; Equipe Morphogenèse et phénomènes multi-échelle Team

    2015-03-01

    Everyone can make the observation: a rubber balloon inflated until it spontaneously pop breaks into a large number of shreds. In contrast, a balloon pierced with a needle at an early stage of its inflation breaks into two large pieces. Using model latex balloons, we have experimentally investigated the transition between these two breaking regimes. We have showed that, above a threshold stress in the latex membrane, a single crack become unstable and separates into two new cracks. Then, a cascade of tip-splitting generates a network of cracks that eventually form a large number of fragments. We have observed that the instability of the crack occurs when it reaches a limit velocity that could the speed of sound. By studying the energy balance during the explosion, we can determine the intrinsic fracture energy of rubber, a measurement difficult to achieve with usual tensile testing.

  3. Rubber curing chemistry governing the orientation of layered silicate

    Directory of Open Access Journals (Sweden)

    2007-11-01

    Full Text Available The effect of curing systems on the orientation and the dispersion of the layered silicates in acrylonitrile butadiene rubber nanocomposite is reported. Significant differences in X-ray diffraction pattern between peroxide curing and sulfur curing was observed. Intense X-ray scattering values in the XRD experiments from peroxide cured vulcanizates indicate an orientation of the layers in a preferred direction as evinced by transmission electron micrographs. However, sulfur cured vulcanizates show no preferential orientation of the silicate particles. Nevertheless, a closer inspection of transmission electron microscopy (TEM images of peroxide and sulfur cured samples shows exfoliated silicate layers in the acrylonitrile butadiene rubber (NBR matrix. It was revealed in the prevailing study that the use of an excess amount of stearic acid in the formulation of the sulfur curing package leads to almost exfoliated type X-ray scattering pattern.

  4. Use of silicone rubber to facilitate shunt takedown.

    Science.gov (United States)

    Laks, H

    1981-07-01

    The takedown of systemic-pulmonary artery shunts at the time of corrective operation is time-consuming and potentially dangerous because of adhesions at the previous operative site. A method of facilitating shunt takedown is described in which a strip of silicone rubber is used to surround the subclavian artery or polytetrafluoroethylene graft interposed between the subclavian artery and the pulmonary artery. The ends of the strip are left loosely attached to the anterior mediastinum so that an adhesion-free plane is left between the strips down to the shunt. The experience of the Yale University School of Medicine with this technique in 14 patients is described. Five underwent reoperation, at which time the silicone rubber strip facilitated access to the shunt and shunt takedown.

  5. Epoxidized natural rubber and hydrotalcite compounds: rheological and thermal characterization

    Directory of Open Access Journals (Sweden)

    Vanessa Macedo da Silva

    2017-09-01

    Full Text Available Abstract Epoxidized natural rubber (ENR and synthetic non-modified hydrotalcite (HT compounds were prepared and evaluated. Natural rubber (NR was epoxidized with 20.6% of epoxy groups from a chemical modification of the latex. A sulfur-based curing system formulation with accelerators was used. The amounts of HT in the ENR-HT compositions was varied between 0, 2, 3 and 5 phr. All compositions were evaluated as to cure parameters, rheological properties, thermal resistance and crosslink density. The results showed that the mineral filler does not have a significant influence on the cure parameters. Different methods of crosslink density determination were used (swelling at equilibrium and elastic modulus. The results turn out to be equivalent and rise as the amount of filler is increased. The best results were found for the 5 phr hydrotalcite compound (ENR-HT5.

  6. Silicone Rubber Superstrate Loaded Patch Antenna Design Using Slotting Technique

    Science.gov (United States)

    Kaur, Bhupinder; Saini, Garima; Saini, Ashish

    2016-09-01

    For the protection of antenna from external environmental conditions, there is a need that antenna should be covered with a stable, non-reactive, highly durable and weather resistive material which is insensitive to changing external environment. Hence, in this paper silicone rubber is proposed as a superstrate layer for patch antenna for its protection. The electrical properties of silicon rubber sealant are experimentally found out and its effect of using as superstrate on coaxial fed microstrip patch antenna using transmission line model is observed. The overall performance is degraded by slightly after the use of superstrate. Further to improve the performance of superstrate loaded antenna, patch slots and ground defects have been proposed. The proposed design achieves the wideband of 790 MHz (13.59 %), gain of 7.12 dB, VSWR of 1.12 and efficiency of 83.02 %.

  7. Applications of Raman spectroscopy to the analysis of natural rubber

    Science.gov (United States)

    Hendra, Patrick J.; Jackson, Kevin D. O.

    1994-10-01

    The technique of Raman spectroscopy has been available for over 60 years but the analysis of elastomers has been dogged by problems of fluorescence. The introduction of Fourier transform collection techniques and spectral accumulation, coupled with the advantages of using a near-IR laser as an excitation source, have removed many of the barriers to the application of this technique within a routine laboratory environment. This paper describes some of the areas related to the analysis of natural rubber which have been investigated using this technique. Of particular interest is the observation of main chain modifications during vulcanization and the ability to observe the conversion of insoluble to soluble sulphur under conditions appropriate to compounding and vulcanization. The influence of crystallization, both temperature and strain induced, on the FT-Raman spectrum of natural rubber is also demonstrated.

  8. Motor imagery enhancement paradigm using moving rubber hand illusion system.

    Science.gov (United States)

    Minsu Song; Jonghyun Kim

    2017-07-01

    Motor imagery (MI) has been widely used in neurorehabilitation and brain computer interface. The size of event-related desynchronization (ERD) is a key parameter for successful motor imaginary rehabilitation and BCI adaptation. Many studies have used visual guidance for enhancement/ amplification of motor imagery ERD amplitude, but their enhancements were not significant. We propose a novel ERD enhancing paradigm using body-ownership illusion, or also known as rubber hand illusion (RHI). The system was made by motorized, moving rubber hand which can simulate wrist extension. The amplifying effects of the proposed RHI paradigm were evaluated by comparing ERD sizes of the proposed paradigm with motor imagery and actual motor execution paradigms. The comparison result shows that the improvement of ERD size due to the proposed paradigm was statistically significant (pparadigms.

  9. Nonlinear Conductive Behaviour of Silver Nanowires/Silicone Rubber Composites

    Science.gov (United States)

    Lu, Pin; Qu, Zhaoming; Wang, Qingguo; Bai, Liyun; Zhao, Shiyang

    2018-01-01

    Silver nanowires with an average length of 10 μm and diameter of about 90 nm have been synthesized by polyol reduction of silver nitrate in the presence of polyvinylpyrrolidone(PVP). Silver nanowires (AgNWs)/silicone rubber (SR) composites have been made by mixing silver nanowires into silicone rubber. The nonlinear response of AgNWs/SR composites under high electric field is investigated. The nonlinear Conductive behavior of composites is considered as a competitive process of several effects. From the perspective of the microstructure of composites, the conductive path is established by the quantum tunnel effect between silver nanowires. The influence factors on the conductivity of composites are discussed and analyzed. The results show that the AgNWs/SR composites with nonlinear conductive properties are of great potential application in electromagnetic protection of electron device and system.

  10. Theory of Thermodynamic Variables of Rubber Band Heat Engine

    International Nuclear Information System (INIS)

    Muharayu, Nurhidayah; Widayani; Khairurrijal

    2016-01-01

    Rubber band heat engine is a heat engine that is easily applied in the experiment. However, to get the data from the experimental results are required a formulation that is able to accommodate the data, so that it will be obtained an accurate value. We show and analyze the variables thermodynamic formulation of rubber band heat engine to accommodate the experimental data, so that the equation of state, heat, work and efficiency are not only studied theoretically but also experimentally. The engine's efficiency is calculated for an idealized but reasonable model. The engine's work cycle is compared with a Carnot cycle, and it is shown to be equivalent to the Carnot cycle as an extremely ideal limiting case. We measured the force law parameters for a working model, and we obtained the efficiency of this model. (paper)

  11. EARLY DOWNHOME BLUES IN AMERICAN CULTURE

    OpenAIRE

    Muhni, Djuhertati Imam

    2012-01-01

    People's traditional music and the way people behave when performing it are symbolic expressions of broad cultural pattern and social organization . In other words music is a part of men's learned heritage . Hence this study is about music in a given culture, specifically blues in American culture . Allen Trachtenberg stated that blues songs are inheritance from the American past for negotiating black people's lives as Americans . In the experience of blues the African-Americans find themselv...

  12. The Red-Blue Transportation Problem

    OpenAIRE

    Vancroonenburg, Wim; Della Croce, Federico; Goossens, Dries; Spieksma, Frits

    2014-01-01

    This paper considers the Red-Blue Transportation Problem (Red-Blue TP), a generalization of the transportation problem where supply nodes are partitioned into two sets and so-called exclusionary constraints are imposed. We encountered a special case of this problem in a hospital context, where patients need to be assigned to rooms. We establish the problem's complexity, and we compare two integer programming formulations. Furthermore, a maximization variant of Red-Blue TP is presented, for...

  13. Interesting green elastomeric composites: silk textile reinforced natural rubber

    OpenAIRE

    Smitthipong, Wirasak; Suethao, Sukontip; Shah, Darshil Upendra; Vollrath, Fritz

    2016-01-01

    © 2016 Elsevier LtdThe reinforcement of natural rubber (NR) with particles and fibres enables their use in even high performance applications, such as in road-racing bicycle tire casings. Here, for the first time, we examine the potential of silk textiles as reinforcements in NR to produce a fully-green, flexible yet strengthened elastomeric composite material. Various material properties were evaluated and compared with similar nylon textile reinforced NR composites. Two types of NR were use...

  14. Radiation vulcanized natural rubber latex is not cytotoxic

    International Nuclear Information System (INIS)

    Nakamura, Akitada; Ikarashi, Y.; Tsuchiya, T.; Kaniwa, M.

    1990-01-01

    It has been reported that urethritis and/or urethral strictures caused by urinary catheters relates to cytotoxicities of their materials, and that natural rubber latex (NRL) materials often show the strong cytotoxicities. This paper reports the cytotoxicity testing method using chinese hamster V79 cultured cells, clarifies that the toxicities of NRLs vulcanized by the conventional processes are due mainly to the contents of zinc dialkyldithiocarbamates in the materials, and that the cytotoxicity of radiation vulcanized NRL (RVNRL) is very weak. (author)

  15. Radiation vulcanised natural rubber latex (RVNRL) market and challenges

    International Nuclear Information System (INIS)

    Wan Manshol Wan Zin; Najib Mohamad Zakey; Chai Chee Keong

    2000-01-01

    RVNRL has the required properties and proven useful for the manufacturing of examination gloves, balloons and finger cots at industrial scale. To date only RVNRL finger cots are available in the market. Problems and challenges for the market of other products are identified. Further success in the on going research activities will be the reference for more applications of RVNRL in the relevant industry to produce natural rubber latex products of more competitive values

  16. Silver nanoparticles delivery system based on natural rubber latex membranes

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, Eder Jose, E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo/FFCLRP-DF (Brazil); Kinoshita, Angela [Universidade do Sagrado Coracao (Brazil); Ramos, Ana Paula [Universidade de Sao Paulo/FFCLRP-DQ (Brazil); Baffa, Oswaldo [Universidade de Sao Paulo/FFCLRP-DF (Brazil)

    2013-04-15

    The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV-Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane ({approx}0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are

  17. Cercosporiose progression in the agroforestry consortium coffee-rubber trees

    Directory of Open Access Journals (Sweden)

    Humberto Godoy Androcioli

    2015-12-01

    Full Text Available Cercospora coffeicola is one of the primary diseases that affect coffee plants. Studies indicate that shaded coffee plants reduce the incidence of this disease and that the management of trees and coffee plants arrangement influence in the dissemination of cercospora. The objective of this study was to evaluate the incidence and severity of C. coffeicola at different distances from double rows of rubber trees (Hevea brasiliensis muell. arg. at two different sunlight exposures (north and south. This study was conducted in Londrina, Parana, between 2008 and 2010, with adult plants of the IAPAR 59 cultivar (Coffea arabica L. grown at a spacing of 2.5 m x 1.0 m. The distances between the double rows of rubber trees were 13, 16 and 22 m, compared to plants grown under full sun. The disease incidence was assessed monthly by using a non-destructive method. This analysis was conducted on coffee leaves from the third and fourth pairs of two plagiotropic branches, on eight plants per plot, with five replications. These data were used to calculate the area under the curve for the incidence of the brown eye spot. The highest disease incidence occurred in the coffee plants grown under full sun, whereas lowest disease occurred on plants located at up to two meters away from double rows of rubber trees. The incidence of Cercospora leaf spot increased with the distance from the double rows of rubber trees. The results demonstrate that the mapping of cercospora incidence in shaded coffee plants is essential to determinate the best spacing and plants arrangement.

  18. EVALUATION OF TIRE RUBBER DISPOSAL IN CONCRETE FOR PAVEMENTS

    OpenAIRE

    Rosa Cristina Cecche Lintz; Maria Rachel Russo Seydell

    2009-01-01

    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...

  19. Shape memory alloy wire-based smart natural rubber bearing

    International Nuclear Information System (INIS)

    Hedayati Dezfuli, F; Shahria Alam, M

    2013-01-01

    In this study, two types of smart elastomeric bearings are presented using shape memory alloy (SMA) wires. Due to the unique characteristics of SMAs, such as the superelastic effect and the recentering capability, the residual deformation in SMA-based natural rubber bearings (SMA-NRBs) is significantly reduced whereas the energy dissipation capacity is increased. Two different configurations of SMA wires incorporated in elastomeric bearings are considered. The effect of several parameters, including the shear strain amplitude, the type of SMA, the aspect ratio of the base isolator, the thickness of SMA wire, and the amount of pre-strain in the wires on the performance of SMA-NRBs is investigated. Rubber bearings are composed of natural rubber layers bonded to steel shims as reinforcement. Results show that ferrous SMA wire, FeNiCuAlTaB, with 13.5% superelastic strain and a very low austenite finish temperature (−62 °C), is the best candidate to be used in SMA-NRBs subjected to high shear strain amplitudes. In terms of the lateral flexibility and wire strain level, the smart rubber bearing with a cross configuration of SMA wires is more efficient. Moreover, the cross configuration can be implemented in high-aspect-ratio elastomeric bearings since the strain induced in the wire does not exceed the superelastic range. When cross SMA wires with 2% pre-strain are used in a smart NRB, the dissipated energy is increased by 74% and the residual deformation is decreased by 15%. (paper)

  20. Analysis of Work Design in Rubber Processing Plant

    OpenAIRE

    Wahyuni Dini; Nasution Harmein; Budiman Irwan; Wijaya Khairini

    2018-01-01

    The work design illustrates how structured jobs, tasks, and roles are defined and modified and their impact on individuals, groups, and organizations. If the work is not designed well, the company must pay greater costs for workers’ health, longer production processes or even penalties for not being able to meet the delivery schedule. This is visible to the condition in a rubber processing factory in North Sumatra. Work design aspects such as layouts, machinery and equipment, worker's physica...

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2005-08-01

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

  3. Study on determination of durability analysis process and fatigue damage parameter for rubber component

    International Nuclear Information System (INIS)

    Moon, Seong In; Cho, Il Je; Woo, Chang Su; Kim, Wan Doo

    2011-01-01

    Rubber components, which have been widely used in the automotive industry as anti-vibration components for many years, are subjected to fluctuating loads, often failing due to the nucleation and growth of defects or cracks. To prevent such failures, it is necessary to understand the fatigue failure mechanism for rubber materials and to evaluate the fatigue life for rubber components. The objective of this study is to develop a durability analysis process for vulcanized rubber components, that can predict fatigue life at the initial product design step. The determination method of nonlinear material constants for FE analysis was proposed. Also, to investigate the applicability of the commonly used damage parameters, fatigue tests and corresponding finite element analyses were carried out and normal and shear strain was proposed as the fatigue damage parameter for rubber components. Fatigue analysis for automotive rubber components was performed and the durability analysis process was reviewed

  4. Radiation shielding rubber blend and radiation ray shielding packing material molded therefrom

    International Nuclear Information System (INIS)

    Takechi, Sanjuro; Urakami, Masamichi.

    1996-01-01

    The present invention concerns a flexible radiation shielding packing material having a good molding fabricability in a not cross-linked state, and having excellent tensile strength, stretchability and tearing resistance. The blend is formed by blending ethylene/propylene rubber (EPR (copolymer of ethylene and propylene), EPDM (terpolymer of ethylene, propylene and a slight amount of dienic ingredient)) and isopropylene rubber (IR) with lead oxide. The blending ratio is preferably from 30 to 100 parts by weight of a lead oxide powder based on 100 parts by weight of a rubber comprising ethylene/propylene rubber and isopropylene rubber at a weight ratio of from 3:7 to 7:3. If ethylene/propylene rubber is EPDM, it is more preferable. (T.M.)

  5. Variable blue straggler stars in NGC 5466

    International Nuclear Information System (INIS)

    Harris, H.C.; Mateo, M.; Olszewski, E.W.; Nemec, J.M.

    1990-01-01

    Nine variable blue stragglers have been found in the globular cluster NGC 5466. The six dwarf Cepheids in this cluster coexist in the instability strip with other nonvariable stars. The three eclipsing binaries are among the hottest of the blue stragglers. The hypothesis is discussed that all blue stragglers in this cluster have undergone mass transfer in close binaries. Under this hypothesis, rotation and spin-down play important roles in controlling the evolution of blue stragglers in old clusters and in affecting some of their observational properties. 14 refs

  6. Morphological responses of wheat to blue light

    Science.gov (United States)

    Barnes, C.; Bugbee, B.

    1992-01-01

    Blue light significantly increased tillering in wheat (Triticum aestivum L.) plants grown at the same photosynthetic photon flux (PPF). Plants were grown under two levels of blue light (400-500 nm) in a controlled environment with continuous irradiation. Plants received either 50 micromoles m-2 s-1 of blue light or 2 micromoles m-2 s-1 blue light from filtered metal halide lamps at a total irradiance of 200 micromoles m-2 s-1 PPF (400-700 nm). Plants tillered an average of 25% more under the higher level of blue light. Blue light also caused a small, but consistent, increase in main culm development, measured as Haun stage. Leaf length was reduced by higher levels of blue light, while plant dry-mass was not significantly affected by blue light. Applying the principle of equivalent light action, the results suggest that tillering and leaf elongation are mediated by the blue-UV light receptor(s) because phytochrome photoequilibrium for each treatment were nearly identical.

  7. Why Blue-Collar Blacks Help Less

    OpenAIRE

    Smith, Sandra Susan; Young, Kara Alexis

    2013-01-01

    Why are blue-collar blacks less likely to help jobseekers than jobholders from other ethnoracial groups or even than more affluent blacks? Drawing from in-depth, semi-structured interviews with 97 black and Latino workers at one large, public sector employer, we find that blue-collar black workers both helped less proactively and rejected more requests for assistance than did blue-collar Latino and white-collar black workers. We attribute blue-collar blacks’ more passive engagement to their...

  8. Effect of chain extender on properties of silicone rubber sealant

    Science.gov (United States)

    Liu, Jiesheng; Wu, Shaopeng; Mi, Yixuan; Zhu, Guojun; Zheng, Shaoping

    2010-03-01

    The room-temperature vulcanizing silicone rubber sealant was prepared with chain extender. The effect of chain extender on the properties of silicone rubber sealant was discussed. The composite samples with chain extender were investigated from the aspects of tack-free time, cross-linkage density, hardness (penetration number) and adhesive strength with the concrete slab. It was found that the adding of the chain extender effectively makes the molecular chain length increase and causes the mechanical properties improvement. In addition, the increase in the amount of the chain extender reduces the cross-linkage density and hardness of silicone rubber sealant, which is accompanied with a decrease in the tack-free time. Adhesive strength is one of the most important requirements for sealant. The effect of chain extender on the adhesive strength was also investigated in this study. It was found that the increase in the amount of the chain extender makes the adhesive strength between the sealant and the concrete slab decrease.

  9. Recycling rubber tyres and waste plastics in EAF steelmaking

    Energy Technology Data Exchange (ETDEWEB)

    Sahajwalla, V.; Zaharia, M.; Rahman, M.; Khanna, R.; Saha-Chaudhury, N. [Centre for Sustainable Materials Research and Technology, University of New South Wales, Sydney (Australia); O' Kane, P.; Dicker, J.; Skidmore, C.; Knights, D. [OneSteel, Rooty Hill, Sydney (Australia)

    2011-05-15

    Electric Arc Furnace (EAF) steelmaking uses different carbon based materials as foaming agents. Depending on cost and availability, anthracite and metallurgical coke are among the conventional injecting materials. Considering the energy and green house gas emissions requirements, alternative carbon sources are put on the spot to replace, at least partially, the conventional materials, i.e. waste materials such as rubber and high density polyethylene (HDPE) plastics may react with gas and slag phases resulting in devolatilization, combustion and iron oxide reduction reactions. The addition of waste tyres and waste plastics in EAF steelmaking has been studied in detail by our groups at UNSW and OneSteel is developing a method for EAFs to use blends of different proportions of rubber/HDPE plastics and coke as a slag foaming agent. Initially, laboratory investigations were carried out to establish the feasibility of carbon and polymer blends as foaming agents. The enhanced slag foaming performance compared to coke was found to be in good accordance with the results obtained in the laboratory indicating an increased slag volume when using polymeric blends. Following the successful installation of materials handling systems at both plants, the use of a rubber and coke blend is no longer considered a trial and is instead standard practice. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Microwave induced fast pyrolysis of scrap rubber tires

    Science.gov (United States)

    Ani, Farid Nasir; Mat Nor, Nor Syarizan

    2012-06-01

    Pyrolysis is the thermal degradation of carbonaceous solid by heat in the absence of oxygen. The feedstocks, such as biomass or solid wastes are heated to a temperature between 400 and 600°C, without introducing oxygen to support the reaction. The reaction produces three products: gas, pyro-fuel oil and char. This paper presents the techniques of producing pyro-oil from waste tires, as well as investigation of the fuel properties suitable for diesel engine applications. In this study, microwave heating technique is employed to pyrolyse the used rubber tires into pyro-oil. Thermal treatment of as received used rubber tires is carried out in a modified domestic microwave heated fixed bed technology. It has been found that, rubber tires, previously used by various researchers, are poor microwave absorbers. Studies have shown that an appropriate microwave-absorbing material, such as biomass char or activated carbon, could be added to enhance the pyrolysis process; thus producing the pyro-oil. The characteristics of pyro-oil, as well as the effect of microwave absorber on its yield, are briefly described in this paper. The temperature profiles during the microwave heating process are also illustratively emphasized. The study provides a means of converting scrap tires into pyro-oil and pyrolytic carbon black production. The proposed microwave thermal conversion process therefore has the potentials of substantially saving time and energy.

  11. Mechanistic and Economical Characteristics of Asphalt Rubber Mixtures

    Directory of Open Access Journals (Sweden)

    Mena I. Souliman

    2016-01-01

    Full Text Available Load associated fatigue cracking is one of the major distress types occurring in flexible pavement systems. Flexural bending beam fatigue laboratory test has been used for several decades and is considered to be an integral part of the new superpave advanced characterization procedure. One of the most significant solutions to prolong the fatigue life for an asphaltic mixture is to utilize flexible materials as rubber. A laboratory testing program was performed on a conventional and Asphalt Rubber- (AR- gap-graded mixtures to investigate the impact of added rubber on the mechanical, mechanistic, and economical attributes of asphaltic mixtures. Strain controlled fatigue tests were conducted according to American Association of State Highway and Transportation Officials (AASHTO procedures. The results from the beam fatigue tests indicated that the AR-gap-graded mixtures would have much longer fatigue life compared with the reference (conventional mixtures. In addition, a mechanistic analysis using 3D-Move software coupled with a cost analysis study based on the fatigue performance on the two mixtures was performed. Overall, analysis showed that AR modified asphalt mixtures exhibited significantly lower cost of pavement per 1000 cycles of fatigue life per mile compared to conventional HMA mixture.

  12. Investigation of cement based composites made with recycled rubber aggregate

    Directory of Open Access Journals (Sweden)

    Jevtić Dragica Lj.

    2012-01-01

    Full Text Available The results of experimental investigations performed on cement based composites made with addition of recycled rubber as a partial replacement of natural river aggregate are presented in this paper. Different properties of cement based mortar were analyzed, both in fresh and in hardened state. Tested properties in the fresh state included: density, consistency and volume of entrained air. In the hardened state, the following properties were tested: density, mechanical properties (compressive and flexural strength, modulus of elasticity, adhesion to concrete substrate, water absorption, freeze-thaw resistance and ultrasonic pulse velocity. The obtained results indicate that recycled rubber can be successfully applied as a partial replacement of natural river aggregate in cement based composites, in accordance with the sustainable development concept. The investigation showed that physical-mechanical properties of cementituous composites depend to a great extent on the percentage of replacement of natural river aggregate with recycled rubber, especially when the density, strength, adhesion and freeze-thaw resistance are concerned. The best results were obtained in the freeze-thaw resistance of such composites.

  13. Modification of (DGEBA epoxy resin with maleated depolymerised natural rubber

    Directory of Open Access Journals (Sweden)

    2008-04-01

    Full Text Available In this work, diglycidyl ether of bisphenol A (DEGBA type epoxy resin has been modified with maleated depolymerised natural rubber (MDPR. MDPR was prepared by grafting maleic anhydride onto depolymerised natural rubber. MDPR has been characterized by Fourier transform infrared (FT-IR spectroscopy and nuclear magnetic resonance spectroscopy. MDPR was blended with epoxy resin at three different ratios (97/3, 98/2 and 99/1, by keeping the epoxy resin component as the major phase and maleated depolymerised natural rubber component as the minor phase. The reaction between the two blend components took place between the acid/anhydride group in the MDPR and the epoxide group of the epoxy resin. The proposed reaction schemes were supported by the FT-IR spectrum of the uncured Epoxy/MDPR blends. The neat epoxy resin and Epoxy/MDPR blends were cured by methylene dianiline (DDM at 100°C for three hours. Thermal, morphological and mechanical properties of the neat epoxy and the blends were investigated. Free volume studies of the cured, neat epoxy and Epoxy/MDPR blends were correlated with the morphological and mechanical properties of the same systems using Positron Annihilation Lifetime Studies.

  14. FE Prediction of Hysteretic Component of Rubber Friction

    Directory of Open Access Journals (Sweden)

    L. Pálfi

    2012-01-01

    Full Text Available The hysteretic part of the friction coefficient for rubber sliding on an ideal rigid, rough surface has been investigated by FE technique. The FE models were created by using two different FE softwares, ABAQUS and MSC.MARC. The surface roughness has been considered by using two different sine waves having a wavelength of 100 μm and 11.11 μm, as well as their superposition. Parameters of the viscoelastic material models of the rubber were gained, firstly from a fit to the measured storage modulus, secondly from a fit to the measured loss factor master curve of the rubber. The effect of viscoelastic material models, comparing 10-term and 40-term generalized Maxwell models was also considered together with the temperature effect between −50 and 150°C. According to the results, both postprocessing methods, namely, the reaction force and the energy-based approach, show very similar coefficients of friction. The 40-term Maxwell model fitted to both the storage modulus and loss factor curve provided the most realistic results. The tendency of the FE results has been explained by semianalytical theory.

  15. Functional buckling behavior of silicone rubber shells for biomedical use.

    Science.gov (United States)

    van der Houwen, E B; Kuiper, L H; Burgerhof, J G M; van der Laan, B F A M; Verkerke, G J

    2013-12-01

    The use of soft elastic biomaterials in medical devices enables substantial function integration. The consequent increased simplification in design can improve reliability at a lower cost in comparison to traditional (hard) biomaterials. Functional bi-stable buckling is one of the many new mechanisms made possible by soft materials. The buckling behavior of shells, however, is typically described from a structural failure point of view: the collapse of arches or rupture of steam vessels, for example. There is little or no literature about the functional elastic buckling of small-sized silicone rubber shells, and it is unknown whether or not theory can predict their behavior. Is functional buckling possible within the scale, material and pressure normally associated with physiological applications? An automatic speech valve is used as an example application. Silicone rubber spherical shells (diameter 30mm) with hinged and double-hinged boundaries were subjected to air pressure loading. Twelve different geometrical configurations were tested for buckling and reverse buckling pressures. Data were compared with the theory. Buckling pressure increases linearly with shell thickness and shell height. Reverse buckling shows these same relations, with pressures always below normal buckling pressure. Secondary hinges change normal/reverse buckling pressure ratios and promote symmetrical buckling. All tested configurations buckled within or closely around physiological pressures. Functional bi-stable buckling of silicone rubber shells is possible with adjustable properties in the physiological pressure range. Results can be predicted using the proposed relations and equations. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Pushing the Limits: The Pattern and Dynamics of Rubber Monoculture Expansion in Xishuangbanna, SW China.

    Directory of Open Access Journals (Sweden)

    Huafang Chen

    Full Text Available The rapidly growing car industry in China has led to an equally rapid expansion of monoculture rubber in many regions of South East Asia. Xishuangbanna, the second largest rubber planting area in China, located in the Indo-Burma biodiversity hotspot, supplies about 37% of the domestic natural rubber production. There, high income possibilities from rubber drive a dramatic expansion of monoculture plantations which poses a threat to natural forests. For the first time we mapped rubber plantations in and outside protected areas and their net present value for the years 1988, 2002 (Landsat, 30 m resolution and 2010 (RapidEye, 5 m resolution. The purpose of our study was to better understand the pattern and dynamics of the expansion of rubber plantations in Xishuangbanna, as well as its economic prospects and conservation impacts. We found that 1 the area of rubber plantations was 4.5% of the total area of Xishuangbanna in 1988, 9.9% in 2002, and 22.2% in 2010; 2 rubber monoculture expanded to higher elevations and onto steeper slopes between 1988 and 2010; 3 the proportion of rubber plantations with medium economic potential dropped from 57% between 1988 and 2002 to 47% in 2010, while the proportion of plantations with lower economic potential had increased from 30% to 40%; and 4 nearly 10% of the total area of nature reserves within Xishuangbanna has been converted to rubber monoculture by 2010. On the basis of our findings, we conclude that the rapid expansion of rubber plantations into higher elevations, steeper terrain, and into nature reserves (where most of the remaining forests of Xishuangbanna are located poses a serious threat to biodiversity and environmental services while not producing the expected economic returns. Therefore, it is essential that local governments develop long-term land use strategies for balancing economic benefits with environmental sustainability, as well as for assisting farmers with the selection of land suitable

  17. Periodic Visuotactile Stimulation Slowly Enhances the Rubber Hand Illusion in Individuals with High Autistic Traits

    OpenAIRE

    Ide, Masakazu; Wada, Makoto

    2016-01-01

    In a rubber hand illusion (RHI) task, synchronous brush stroking of a rubber hand and a participant's hidden hand induces body ownership of the rubber hand. The effects of spatial distances and temporal lags on the RHI have been extensively examined; however, the effect of periodicity of the stimuli on illusory body ownership has not been examined. Meanwhile, the occurrence of RHI tends to be weak in individuals with autism-spectrum disorders (ASD) and high autistic traits. Preference for sti...

  18. Design of the Nonlinear Pin Rubber Forming Equipment Integrating the Functions of Extruding, Dewatering, Drying & Expanding

    OpenAIRE

    Yuefeng Yuan; Yue Zheng; Wenying Zhang; Guoping Liu; Nengjun Yuan; Honghui Shi

    2014-01-01

    The top priority of car-tire suppliers is to improve wetland grip force of the using tires, reduce the rolling resistance and the rolling noise of tires. It is urgent for the tire industry to research and develop high-performance tires to solve the above problems. They must use the high- performance synthetic rubber and auxiliary rubber to develop the most advanced manufacturing technologies and equipment. Silica, a kind of important tire auxiliary rubber, can significantly reduce the rolling...

  19. Effect of quaternary ammonium salts in the process of extracting oil filled rubber from latex

    Directory of Open Access Journals (Sweden)

    N. S. Nikulina

    2016-01-01

    Full Text Available Currently, much attention is paid to the improvement of production technology of synthetic rubber. Much attention is given to rubber is produced by emulsion polymerization. This is due to the fact that rubbers produced by emulsion polymerization have a number of positive characteristics, and are widely used in the tire and rubber industry, in composite formulations for various purposes. In recent years, the technology of production of synthetic rubbers are widely used quaternary ammonium salts which are produced on an industrial scale. Application low and high molecular weight quaternary ammonium salts to reduce pollution of environ-mental protection, exclude the use of mineral salts without significant changes in the process flowsheet. It is found that quaternary ammonium salts react with the components of the emulsion system to form insoluble complexes, which are captured produced rubber crumb. However, Applications, quaternary salts in the manufacture of oil-filled rubber in the literature sources have not been given due attention. The study presents the results of research on the effect of the concentration of a coagulating agent, tempera tours and concentration of the dispersed phase in the process of coagulation of latex in the preparation of oil-filled rubber stamps SCS-30 ARKM-15. The concentration of the coagulating agent does not significantly affect the process of separation of the rubber from the latex. The process of isolation rubber latex is advantageously carried out at a reduced temperature. The concentration of the dispersed phase also provides material effect on the coagulation process. The lead researches mouthestablished that produced rubber, rubber compounds and vulcanizates based on these indicators correspond to their requirements.

  20. Electric Field and Potential Distributions along Surface of Silicone Rubber Polymer Insulators Using Finite Element Method

    OpenAIRE

    B. Marungsri; W. Onchantuek; A. Oonsivilai

    2008-01-01

    This paper presents the simulation the results of electric field and potential distributions along surface of silicone rubber polymer insulators. Near the same leakage distance subjected to 15 kV in 50 cycle salt fog ageing test, alternate sheds silicone rubber polymer insulator showed better contamination performance than straight sheds silicone rubber polymer insulator. Severe surface ageing was observed on the straight sheds insulator. The objective of this work is to ...