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Sample records for huge rubber band

  1. Shape memory rubber bands & supramolecular ionic copolymers

    Science.gov (United States)

    Brostowitz, Nicole

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

  2. Rubber Bands as Model Polymers in Couette Flow

    Science.gov (United States)

    Dunstan, Dave E.

    2008-01-01

    We present a simple device for demonstrating the essential aspects of polymers in flow in the classroom. Rubber bands are used as a macroscopic model of polymers to allow direct visual observation of the flow-induced changes in orientation and conformation. A transparent Perspex Couette cell, constructed from two sections of a tube, is used to…

  3. Results of rubber band ligation of esophageal varices.

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    Leszczyszyn, J; Łebski, I; Massopust, R; Skoczylas, M; Janus, W

    2001-05-01

    The aim of the paper is to analyze the results of endoscopic rubber band ligation of esophageal varices performed between 1 January 1998 and 1 November 2000 at the Department of GI Surgery of 4th Military University Hospital. Cases of 50 patients with massive upper GI variceal bleeding present on admission or with the history of such a bleeding were reviewed. A total of 85 endoscopic procedures of rubber band ligation were performed. In 9 (18%) cases ligation was performed due to massive variceal bleeding, in 1 case the complementary obliteration of stomach fundus varices with Aethoxysclerol was performed. In 10 (20%) cases in grade C of Child-Pough scale of liver failure, 3 endoscopic procedures were performed, in 15 (30%) in grade B--2 procedures, in the remaining 25 (50%) cases, also in grade B--1 procedure was performed. Procedures were conducted with Wilson-Cook Multi-Band Ligator SAEED SixShooter. In all cases with non-bleeding esophageal varices the overall good result of treatment was achieved, with collapsing of variceal columns. In 8 (88.8%) of 9 cases treated due to variceal bleeding, good hemostasis was achieved and no reintervention was necessary. In 1 case of massive variceal bleeding endoscopic treatment failed and patient eventually died. In 25 (50%) cases the complementary (1 or 2) rubber band ligations were performed. Follow-up period has ranged from 1 to 34 months. No cases of severe complications after the procedure were noted. In early period after the procedure 43 (86%) patients complained of transient, mild retrosternal pain and mild to moderate dysphagia. Endoscopic rubber band ligation is a safe and effective treatment for esophageal varices both in cases of variceal bleeding and as elective procedure.

  4. Theory of Thermodynamic Variables of Rubber Band Heat Engine

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    Muharayu, Nurhidayah; Widayani; Khairurrijal

    2016-08-01

    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.

  5. Rubber band ligation of hemorrhoids: A guide for complications

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    Albuquerque, Andreia

    2016-01-01

    Rubber band ligation is one of the most important, cost-effective and commonly used treatments for internal hemorrhoids. Different technical approaches were developed mainly to improve efficacy and safety. The technique can be employed using an endoscope with forward-view or retroflexion or without an endoscope, using a suction elastic band ligator or a forceps ligator. Single or multiple ligations can be performed in a single session. Local anaesthetic after ligation can also be used to reduce the post-procedure pain. Mild bleeding, pain, vaso-vagal symptoms, slippage of bands, priapism, difficulty in urination, anal fissure, and chronic longitudinal ulcers are normally considered minor complications, more frequently encountered. Massive bleeding, thrombosed hemorrhoids, severe pain, urinary retention needing catheterization, pelvic sepsis and death are uncommon major complications. Mild pain after rubber band ligation is the most common complication with a high frequency in some studies. Secondary bleeding normally occurs 10 to 14 d after banding and patients taking anti-platelet and/or anti-coagulant medication have a higher risk, with some reports of massive life-threatening haemorrhage. Several infectious complications have also been reported including pelvic sepsis, Fournier’s gangrene, liver abscesses, tetanus and bacterial endocarditis. To date, seven deaths due to these infectious complications were described. Early recognition and immediate treatment of complications are fundamental for a favourable prognosis. PMID:27721924

  6. [Gangrene of the penis due to strangulation by a rubber band: a case report].

    Science.gov (United States)

    Sasaki, Yutaro; Oda, Shinpei; Fujikata, Shiro; Tanimoto, Shuji; Kan, Masaharu

    2014-03-01

    We report a case of strangulation of the penis by a rubber band. A 79-year-old man placed a rubber band tightly around the corona of his glans penis in order to prevent urinary incontinence. After five days, he was taken to our hospital in an ambulance for high temperature and general malaise. We found the rubber band and removed it immediately. Gangrene of the penis continued and he did not recover from sepsis, so we performed partial penectomy. After the operation, he completely recovered. Penile strangulation using a soft constricting object such as a rubber band might result in severe complications and we should be careful.

  7. Infrared coagulation versus rubber band ligation in early stage hemorrhoids

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    P.J. Gupta

    2003-10-01

    Full Text Available The ideal therapy for early stages of hemorrhoids is always debated. Some are more effective but are more painful, others are less painful but their efficacy is also lower. Thus, comfort or efficacy is a major concern. In the present randomized study, a comparison is made between infrared coagulation and rubber band ligation in terms of effectiveness and discomfort. One hundred patients with second degree bleeding piles were randomized prospectively to either rubber band ligation (N = 54 or infrared coagulation (N = 46. Parameters measured included postoperative discomfort and pain, time to return to work, relief in incidence of bleeding, and recurrence rate. The mean age was 38 years (range 19-68 years. The mean duration of disease was 17.5 months (range 12 to 34 months. The number of male patients was double that of females. Postoperative pain during the first week was more intense in the band ligation group (2-5 vs 0-3 on a visual analogue scale. Post-defecation pain was more intense with band ligation and so was rectal tenesmus (P = 0.0059. The patients in the infrared coagulation group resumed their duties earlier (2 vs 4 days, P = 0.03, but also had a higher recurrence or failure rate (P = 0.03. Thus, we conclude that band ligation, although more effective in controlling symptoms and obliterating hemorrhoids, is associated with more pain and discomfort to the patient. As infrared coagulation can be conveniently repeated in case of recurrence, it could be considered to be a suitable alternative office procedure for the treatment of early stage hemorrhoids.

  8. MANAGEMENT OF INTERNAL HEMORRHOID WITH RUBBER BAND LIGATION PROCEDURE

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    I Made Arya Winangun

    2013-10-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Hemorrhoid is regarded as the cases most seen in population. The prevalence of this cases about 4,4% with the incidence 12 of 1.000 patient. The current management of hemorrhoid is lifestyle modification, conservative management such as farmacology, minimally invasive treatment and more aggressive therapy using surgical procedure. Rubber band ligation was one of the minimally invasive procedures. This procedure was easy, inexpensive, and can be done outpatient using simple tools without complicated procedure like hemorrhoidectomy. Some studies explained rubber band ligation effectively done in internal hemorrhoid grade II and grade III even this procedure still had minimal complication such as bleeding and unpleasentness /* 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-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  9. Visual nesting system for irregular cutting-stock problem based on rubber band packing algorithm

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    Xiaoping Liao

    2016-05-01

    Full Text Available This article deals with the packing problem of irregular items allocated into a rectangular sheet to minimize the waste. Conventional solution is not visual during the packing process. It obtains a reasonable and relatively satisfactory solution between the nesting time and nesting solution. This article adopts a physical method that uses rubber band packing algorithm to simulate a rubber band wrapping those packing irregular items. The simulation shows a visual and fast packing process. The resultant rubber band force is applied in the packing items to translate, rotate, and slide them to make the area decrease and obtain a high packing density. An improved analogy QuickHull algorithm is presented to obtain extreme points of rubber band convex hull. An adaptive module could set a variable rubber band force and a variable time step to make a proper convergence and no intersection. A quick convex decomposition method is used to solve the problem of concave polygon. A plural vector expression approach is adopted to calculate the resultant vector of the rubber band force. Several cases are compared with the benchmark problems to prove rubber band packing algorithm performance.

  10. Triple rubber band ligation for hemorrhoids: prospective, randomized trial of use of local anesthetic injection.

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    Law, W L; Chu, K W

    1999-03-01

    Rubber band ligation is a common office procedure for hemorrhoids. Triple rubber band ligation in a single session has been shown to be a safe and economical way of treating hemorrhoids. However, postligation discomfort after triple rubber band ligation is not uncommon. The aim of this study was to evaluate the effectiveness of local anesthetic injection to the banded hemorrhoidal tissue in reducing postligation discomfort. Patients attending an outpatient clinic for symptomatic hemorrhoids suitable for triple rubber band ligation were randomly assigned to two groups. In the treatment group rubber band ligation was performed at three columns of hemorrhoids, and 1 to 2 ml of 2 percent lignocaine was injected into the banded hemorrhoidal tissue. In the control group triple rubber band ligation was performed in a similar manner, but local anesthetic was not given. Patients were followed up by telephone at the second week and in the clinic after six weeks. From April to August 1996, 101 patients entered the trial and were treated with triple rubber band ligation. Sixty-two patients were randomly assigned to the local anesthetic injection group and 39 to the control group. Overall good to excellent results occurred in 89 percent of patients, and there was no difference between the two groups. Postligation pain occurred in 26 and 20 percent of patients in the treatment and control groups, respectively (P > 0.05). Postligation tenesmus occurred in 32 and 41 percent of patients in the treatment and control groups, respectively (P > 0.05). No patients suffered from septic complications or bleeding that required transfusion. Triple rubber band ligation in a single session is a safe, economical, and effective way of treating symptomatic hemorrhoids. Postligation pain and tenesmus occurred in 24 and 37 percent, respectively. Discomfort was usually tolerable. Local anesthetic injection to the banded hemorrhoidal tissue did not help to reduce postligation discomfort.

  11. A prospective randomised study of local anaesthetic injection after multiple rubber band ligation of haemorrhoids.

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    Gokalp, Avni; Baskonus, Ilyas; Maralcan, Gokturk

    2003-01-01

    One hundred and forty-two patients with second and third degree internal haemorrhoids were randomised to rubber band ligation only (n = 72) or rubber band ligation + local anaesthetic injection (n = 70). Pain was assessed by the patients at intervals of 6 hours and 1, 2, 3 and 4 days after banding. Other symptoms, complications, analgesic requirements and patient satisfaction were also recorded for 10 days following the treatment. There was a significant reduction in pain at 60 minutes and 6 hours after the procedure in the rubber band ligation plus local anaesthetic injection patients compared with the rubber band ligation only group (P rubber band ligation only on days 1, 2, 3 and 4 days after ligation. On day 10 after banding, there was no difference between the two groups with respect to symptoms such as nausea, feeling of heaviness and/or tenesmus, fainting; complications, analgesic consumption or overall patient satisfaction. Bupivacaine injection after multiple rubber band ligation may be useful in reducing pain during the first 6 hours of the postbanding period.

  12. [Strangulation of the penis with a rubber band : a case report].

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    Sekii, Yosuke; Katayama, Kinzou; Hayashi, Takuji; Kamoto, Akihito; Kakuta, Youiti; Mori, Naoki; Yoshioka, Toshiaki

    2013-06-01

    We report a case of strangulation of the penis with a rubber band. A 68-year-old man visited our hospital for treatment of a markedly swollen penis. Physical examination revealed one rubber band tightly coiled around the penis. The rubeer band was soon removed, gangrene of the penis continued. A high fever, chills and hypotension were recognized. Sepsis was presumed, and administration of antibiotics was started. Microbiologic cultures revealed streptococcus agalactiae in blood. Since his general condition did not improve, we performed partial penectomy. After the surgery, he showed complete recovery.

  13. A hierarchical layout design method based on rubber band potentialenergy descending

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    Ou Cheng Yi

    2016-01-01

    Full Text Available Strip packing problems is one important sub-problem of the Cutting stock problems. Its application domains include sheet metal, ship making, wood, furniture, garment, shoes and glass. In this paper, a hierarchical layout design method based on rubber band potential-energy descending was proposed. The basic concept of the rubber band enclosing model was described in detail. We divided the layout process into three different stages: initial layout stage, rubber band enclosing stage and local adjustment stage. In different stages, the most efficient strategies were employed for further improving the layout solution. Computational results show that the proposed method performed better than the GLSHA algorithm for three out of nine instances in utilization.

  14. Thermodynamics Fundamental Equation of a "Non-Ideal" Rubber Band from Experiments

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    Ritacco, Herna´n A.; Fortunatti, Juan C.; Devoto, Walter; Ferna´ndez-Miconi, Eugenio; Dominguez, Claudia; Sanchez, Miguel D.

    2014-01-01

    In this paper, we describe laboratory and classroom exercises designed to obtain the "fundamental" equation of a rubber band by combining experiments and theory. The procedure shows students how classical thermodynamics formalism can help to obtain empirical equations of state by constraining and guiding in the construction of the…

  15. Cytotoxicity Comparison of the Nanoparticles Deposited on Latex Rubber Bands between the Original and Stretched State

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    Jung-Hwan Lee

    2014-01-01

    Full Text Available Understanding the biocompatibility of nanoparticles in dental materials is essential for their safe usage in the oral cavity. In this study, we investigated whether nanoparticles deposited on orthodontic latex rubber bands are involved in the induction of cytotoxicity. A method of stretching to three times (“3L” the length of the latex rubber bands was employed to detach the particles using the original length (“L” for comparison. The cytotoxicity tests were performed on extracts with mouse fibroblasts (L929 and human gingival fibroblasts (HGFs. Fourier transform infrared spectroscopy, ion chromatography, elemental analysis, and inductively coupled plasma mass spectrometry (ICP-MS were performed to detect the harmful components in the extracts from rubber bands. There was a significant decrease in the cell viability in the “L” samples compared with the “3L” samples (P<0.05 in the L929 and HGF cells. This was due to the Ni single crystal nanoparticles (~50nm from the inner surface of “L” samples that were detached in the “3L” samples as well as the Zn ion (~9 ppm detected in the extract. This study revealed that the Ni nanoparticles, as well as Zn ions, were involved in the induction of cytotoxicity from the latex rubber bands.

  16. A comparative study of Barron's rubber band ligation with Kshar Sutra ligation in hemorrhoids

    OpenAIRE

    2010-01-01

    Despite a long medical history of identification and treatment, hemorrhoids still pose a challenge to the medical fraternity in terms of finding satisfactory cure of the disease. In this study, Kshar Sutra Ligation (KSL), a modality of treatment described in Ayurveda, was compared with Barron's Rubber Band Ligation (RBL) for grade II and grade III hemorrhoids. This study was conducted in 20 adult patients of either sex with grade II and grade III hemorrhoids at two different hospitals. Patien...

  17. Comparison of rubber band ligation and sclerosant injection for first and second degree haemorrhoids-- a prospective clinical trial.

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    Sim, A J; Murie, J A; Mackenzie, I

    1981-01-01

    Fifty patients with first or mild second degree haemorrhoids were randomly allocated to sclerosant injection (26) or rubber band ligation (24). One year after treatment 24 injection and 22 rubber band ligation patients were assessed. All patients presented with rectal bleeding; injection relieved 14 and rubber band ligation relieved 17 of this symptom (N.S.). Three of seven patients with prolapsing haemorrhoids who had sclerosant injections and five of seven who had rubber band ligation were relieved of this prolapse. However, a further six patients in the injection group developed prolapse for the first time during the one year follow-up period (p less than 0.05). Rubber band ligation relieved anal pain in 10 out of 14 patients whereas injection relieved only one patient of this symptom (p less than 0.05). Neither treatment influenced pruritus ani or faecal soiling. Although rubber band ligation caused more treatment discomfort, it is an effective management for first and mild second degree haemorrhoids and it should be considered as the procedure of choice.

  18. Rubber band motor%橡皮筋发动机

    Institute of Scientific and Technical Information of China (English)

    闵逸萌; 高文莉; 周子恒; 杜立; 王思慧

    2016-01-01

    研究了通过扭转橡皮筋作为驱动力的“发动机”的能量存储与输出。根据观察定义了橡皮筋形变的多阶缠绕,在此基础上建立模型模拟了橡皮筋解旋的能量输出过程。定义了该发动机的各项参量,包括总的旋转时间、有效旋转时间、效率等,探究了能量的分布情况。实验结果表明:橡皮筋发动机的大部分能量转化为螺旋桨的动能和空气动能。%T he properties of a rubber band motor ,a toy motor that stores mechanical energy in a twisted rubber band and releases the energy through an aircraft propeller in an unwinding process , was systematically studied .The strain energy stored in the winded band was converted into three parts:kinetic energy of air ,kinetic energy of propeller ,frictional dissipation of propeller .For each one of them ,a mathematical model was built to account for its contribution to the motor performance . Particularly ,configurations of a twisted rubber band were classified into three types :the primary winding ,the secondary winding and the tertiary winding .Various properties revealed by the experi‐ment were clarified by our theory .

  19. The HubBLe trial: haemorrhoidal artery ligation (HAL versus rubber band ligation (RBL for haemorrhoids

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    Tiernan Jim

    2012-10-01

    Full Text Available Abstract Background Haemorrhoids (piles are a very common condition seen in surgical clinics. After exclusion of more sinister causes of haemorrhoidal symptoms (rectal bleeding, perianal irritation and prolapse, the best option for treatment depends upon persistence and severity of the symptoms. Minor symptoms often respond to conservative treatment such as dietary fibre and reassurance. For more severe symptoms treatment such as rubber band ligation may be therapeutic and is a very commonly performed procedure in the surgical outpatient setting. Surgery is usually reserved for those who have more severe symptoms, as well as those who do not respond to non-operative therapy; surgical techniques include haemorrhoidectomy and haemorrhoidopexy. More recently, haemorrhoidal artery ligation has been introduced as a minimally invasive, non destructive surgical option. There are substantial data in the literature concerning efficacy and safety of 'rubber band ligation including multiple comparisons with other interventions, though there are no studies comparing it to haemorrhoidal artery ligation. A recent overview has been carried out by the National Institute for Health and Clinical Excellence which concludes that current evidence shows haemorrhoidal artery ligation to be a safe alternative to haemorrhoidectomy and haemorrhoidopexy though it also highlights the lack of good quality data as evidence for the advantages of the technique. Methods/design The aim of this study is to establish the clinical effectiveness and cost effectiveness of haemorrhoidal artery ligation compared with conventional rubber band ligation in the treatment of people with symptomatic second or third degree (Grade II or Grade III haemorrhoids. Design: A multi-centre, parallel group randomised controlled trial. Outcomes: The primary outcome is patient-reported symptom recurrence twelve months following the intervention. Secondary outcome measures relate to symptoms

  20. The HubBLe trial: haemorrhoidal artery ligation (HAL) versus rubber band ligation (RBL) for haemorrhoids.

    Science.gov (United States)

    Tiernan, Jim; Hind, Daniel; Watson, Angus; Wailoo, Allan J; Bradburn, Michael; Shephard, Neil; Biggs, Katie; Brown, Steven

    2012-10-25

    Haemorrhoids (piles) are a very common condition seen in surgical clinics. After exclusion of more sinister causes of haemorrhoidal symptoms (rectal bleeding, perianal irritation and prolapse), the best option for treatment depends upon persistence and severity of the symptoms. Minor symptoms often respond to conservative treatment such as dietary fibre and reassurance. For more severe symptoms treatment such as rubber band ligation may be therapeutic and is a very commonly performed procedure in the surgical outpatient setting. Surgery is usually reserved for those who have more severe symptoms, as well as those who do not respond to non-operative therapy; surgical techniques include haemorrhoidectomy and haemorrhoidopexy. More recently, haemorrhoidal artery ligation has been introduced as a minimally invasive, non destructive surgical option.There are substantial data in the literature concerning efficacy and safety of 'rubber band ligation including multiple comparisons with other interventions, though there are no studies comparing it to haemorrhoidal artery ligation. A recent overview has been carried out by the National Institute for Health and Clinical Excellence which concludes that current evidence shows haemorrhoidal artery ligation to be a safe alternative to haemorrhoidectomy and haemorrhoidopexy though it also highlights the lack of good quality data as evidence for the advantages of the technique. The aim of this study is to establish the clinical effectiveness and cost effectiveness of haemorrhoidal artery ligation compared with conventional rubber band ligation in the treatment of people with symptomatic second or third degree (Grade II or Grade III) haemorrhoids. A multi-centre, parallel group randomised controlled trial. The primary outcome is patient-reported symptom recurrence twelve months following the intervention. Secondary outcome measures relate to symptoms, complications, health resource use, health related quality of life and cost

  1. Local anaesthetic infiltration for the rubber band ligation of early symptomatic haemorrhoids: a systematic review and meta-analysis.

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    Sajid, M S; Bhatti, M I; Caswell, J; Sains, P; Baig, M K

    2015-03-01

    The objective of this article is to systematically analyse the randomized, controlled trials evaluating the effectiveness of local anaesthetic infiltration prior to the rubber band ligation of early symptomatic haemorrhoids. Published randomized, controlled trials comparing the use of local anaesthetic (LA) versus no-local anaesthetic (NLA) for the rubber band ligation of early symptomatic haemorrhoids were analysed using RevMan®, and the combined outcomes were expressed as odds ratios (OR) and standardized mean difference (SMD). Four randomized, controlled trials evaluating 387 patients were retrieved from the standard electronic databases. The risk of treatment failure (OR 0.44; 95% CI 0.07, 2.79; z = 0.87; p = 0.39) and post-procedure complications (OR 0.48; 95% CI 0.08, 2.76; z = 0.83; p = 0.41) was similar between two techniques. However, the post-procedure pain score (SMD -5.19; 95% CI -9.08, -1.30; z = 2.62; p rubber band ligation of haemorrhoids under local anaesthetic injection. The use of LA appears to have clinically measurable advantages over NLA in the rubber band ligation of early symptomatic haemorrhoids to lessen post-procedure pain.

  2. Classification of masses on mammograms using rubber-band straightening transform and feature analysis

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    Sahiner, Berkman; Chan, Heang-Ping; Petrick, Nicholas; Helvie, Mark A.; Adler, Dorit D.; Goodsitt, Mitchell M.

    1996-04-01

    A new rubber-band straightening transform (RBST) and texture analysis were developed for classification of masses on mammograms as malignant or benign. A database of 168 mammograms containing biopsy-proven malignant and benign breast masses was digitized at a pixel size of 100 micrometer by 100 micrometer. Regions of interest (ROIs) containing a single mass from each mammogram were extracted by an experienced radiologist. A clustering algorithm was employed for automatic segmentation of each ROI into a mass object and background tissue. A 40-pixel-wide region of the gray-scale image surrounding the mass was transformed onto the Cartesian plane using RBST. The first row of the transformed image contained the pixels along the mass edge. The jth row of the transformed image contained the pixel values at a distance of j pixels from the edge in the normal direction to the edge contour. In the RBST image, mass margins appeared as approximately horizontal edges, and spiculations appeared as approximately vertical lines. Thus, edge sharpness and possible spiculations could be better characterized with directional texture measures. Texture features were extracted from spatial gray-level dependence matrices calculated from the RBST images. Linear discriminant analysis was used for classification, and receiver operating characteristic (ROC) analysis was used to evaluate the classification accuracy. The area Az under the test ROC curve reached 0.87 using cross-validation and 0.89 using the leave-one-case-out method.

  3. A comparative study of Barron's rubber band ligation with Kshar Sutra ligation in hemorrhoids

    Science.gov (United States)

    Singh, Rakhi; Arya, Ramesh C.; Minhas, Satinder S.; Dutt, Anil

    2010-01-01

    Despite a long medical history of identification and treatment, hemorrhoids still pose a challenge to the medical fraternity in terms of finding satisfactory cure of the disease. In this study, Kshar Sutra Ligation (KSL), a modality of treatment described in Ayurveda, was compared with Barron's Rubber Band Ligation (RBL) for grade II and grade III hemorrhoids. This study was conducted in 20 adult patients of either sex with grade II and grade III hemorrhoids at two different hospitals. Patients were randomly allotted to two groups of 10 patients each. Group I patients underwent RBL, whereas patients of group II underwent KSL. Guggul-based Apamarga Kshar Sutra was prepared according to the principles laid down in ancient Ayurvedic texts and methodology standardized by IIIM, Jammu and CDRI, Lucknow. Comparative assessment of RBL and KSL was done according to 16 criteria. Although the two procedures were compared on 15 criteria, treatment outcome of grade II and grade III hemorrhoids was decided chiefly on the basis of patient satisfaction index (subjective criterion) and ability of each procedure to deal with prolapse of internal hemorrhoidal masses (objective criterion): Findings in each case were recorded over a follow-up of four weeks (postoperative days 1, 3, 7, 15 and 30). Statistical analysis was done using Student's t test for parametric data and Chi square test & Mann-Whitney test for non-parametric data. P 0.05). Both the groups were comparable statistically on all other grounds. Kshar Sutra Ligation is a useful form of treatment for Grades II and III internal hemorrhoids. PMID:20814519

  4. Numerical Computation of Electric Field and Potential Along Silicone Rubber Insulators Under Contaminated and Dry Band Conditions

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    Arshad; Nekahi, A.; McMeekin, S. G.; Farzaneh, M.

    2016-09-01

    Electrical field distribution along the insulator surface is considered one of the important parameters for the performance evaluation of outdoor insulators. In this paper numerical simulations were carried out to investigate the electric field and potential distribution along silicone rubber insulators under various polluted and dry band conditions. Simulations were performed using commercially available simulation package Comsol Multiphysics based on the finite element method. Various pollution severity levels were simulated by changing the conductivity of pollution layer. Dry bands of 2 cm width were inserted at the high voltage end, ground end, middle part, shed, sheath, and at the junction of shed and sheath to investigate the effect of dry band location and width on electric field and potential distribution. Partial pollution conditions were simulated by applying pollution layer on the top and bottom surface respectively. It was observed from the simulation results that electric field intensity was higher at the metal electrode ends and at the junction of dry bands. Simulation results showed that potential distribution is nonlinear in the case of clean and partially polluted insulator and linear for uniform pollution layer. Dry band formation effect both potential and electric field distribution. Power dissipated along the insulator surface and the resultant heat generation was also studied. The results of this study could be useful in the selection of polymeric insulators for contaminated environments.

  5. Outcomes of endoscopic treatment of gastroduodenal Dieulafoy's lesion with rubber band ligation and thermal/injection therapy.

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    Mumtaz, Rushda; Shaukat, Masud; Ramirez, Francisco C

    2003-04-01

    Dieulafoy's lesion is a rare but important cause of upper gastrointestinal bleeding. Current endoscopic methods used to treat Dieulafoy's lesion include injection, with or without thermal methods, and mechanical methods. The latter include variceal ligation and hemoclips. There are no studies comparing the outcomes of rubber band ligation and injection with or without thermal therapy. To report the outcomes of Dieulafoy's lesion treated endoscopically with rubber band ligation and injection with or without thermal therapy at a single institution. Patients with the diagnosis of Dieulafoy's lesion treated endoscopically at the Carl T. Hayden VA Medical Center in Phoenix, between August 1994 and August 2002 were analyzed. Demographic data, mode of presentation, risk factors for gastrointestinal bleeding, hemodynamic parameters, blood transfusion requirements, endoscopic findings, details of endoscopic therapy, length of stay in ICU/hospital, complications, recurrence of bleeding, and mortality rates were collected and compared between those receiving endoscopic band ligation (EBL group) and those receiving injection with or without thermal therapy (non-EBL group). Twenty-three patients with Dieulafoy's lesion (14 in the EBL group and nine in the non-EBL group) were studied. All patients were men. The mean age, hemoglobin levels on admission, and the transfusion requirements before therapy were similar in both groups. Fourteen patients (eight in the EBL- and six in the non-EBL groups) presented with hematemesis and the remaining with melena. The majority of Dieulafoy's lesions (91.3%) were located in the stomach and two in the duodenum. Active bleeding at the time of endoscopy was seen in 61% of cases, and immediate hemostasis was achieved with either method in 100% of patients. Early rebleeding (within 72 hours of endoscopic therapy) occurred in only one patient treated with epinephrine plus heater probe therapy. The length of stay in ICU was longer in the non

  6. Comparison and Efficacy of LigaSure and Rubber Band Ligature in Closing the Inflamed Cecal Stump in a Rat Model of Acute Appendicitis

    Directory of Open Access Journals (Sweden)

    Chun-Chieh Yeh

    2015-01-01

    Full Text Available Safety of either LigaSure or rubber band in closing inflamed appendiceal stump in acute appendicitis has been less investigated. In this study, cecal ligation followed by resecting inflamed cecum was performed to mimic appendectomy in a rat model of acute appendicitis. Rats were sacrificed immediately (Group A and 7 days (Group B after cecal resection, respectively. The cecal stumps were closed by silk ligature (S, 5 mm LigaSure (L, or rubber band (R. Seven days after cecal resection, the LigaSure (BL and silk subgroups (BS had significantly less intra-abdominal adhesion and better laparotomy wound healing than rubber band subgroup (BR. The initial bursting pressure at cecal stump was comparable among the three methods; along with tissue healing process, both BL and BS provided a higher bursting pressure than BR 7 days after appendectomy. BL subgroup had more abundant hydroxyproline deposition than BS and BR subgroup. Furthermore, serum TNF-α in BR group kept persistently increasing along with time after cecal resection. Thus, the finding that LigaSure but not rubber band is safe in sealing off the inflamed cecal stump in rat model of acute appendicitis suggests the possibility of applying LigaSure for appendectomy via single port procedure or natural orifice transluminal endoscopic surgery (NOTES.

  7. Thermodynamics of Rubber Elasticity

    Science.gov (United States)

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

    2001-02-01

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

  8. Neurophysiological Correlates of the Rubber Hand Illusion in Late Evoked and Alpha/Beta Band Activity

    Directory of Open Access Journals (Sweden)

    Isa S. Rao

    2017-07-01

    Full Text Available The rubber hand illusion (RHI allows insights into how the brain resolves conflicting multisensory information regarding body position and ownership. Previous neuroimaging studies have reported a variety of neurophysiological correlates of illusory hand ownership, with conflicting results likely originating from differences in experimental parameters and control conditions. Here, we overcome these limitations by using a fully automated and precisely-timed visuo-tactile stimulation setup to record evoked responses and oscillatory responses in participants who felt the RHI. Importantly, we relied on a combination of experimental conditions to rule out confounds of attention, body-stimulus position and stimulus duration and on the combination of two control conditions to identify neurophysiological correlates of illusory hand ownership. In two separate experiments we observed a consistent illusion-related attenuation of ERPs around 330 ms over frontocentral electrodes, as well as decreases of frontal alpha and beta power during the illusion that could not be attributed to changes in attention, body-stimulus position or stimulus duration. Our results reveal neural correlates of illusory hand ownership in late and likely higher-order rather than early sensory processes, and support a role of premotor and possibly intraparietal areas in mediating illusory body ownership.

  9. Local injection of bupivacaine after rubber band ligation of hemorrhoids: prospective, randomized study.

    Science.gov (United States)

    Hooker, G D; Plewes, E A; Rajgopal, C; Taylor, B M

    1999-02-01

    The aim of this study was to determine if local injection of bupivacaine after hemorrhoidal banding causes a decrease in pain and in the incidence of associated symptoms. After hemorrhoidal banding, patients were randomly assigned to receive a local injection of bupivacaine with 1:200,000 epinephrine, an injection of normal saline, or no injection, just superior to each band. Pain was graded by the patient and by the study nurse within 30 minutes, and any associated symptoms were recorded. At intervals 6, 24, and 48 hours postbanding, the patient recorded pain, limitation of activities, and analgesic requirements. Associated symptoms while at home were recorded. Of 115 patients studied, 42 received bupivacaine injection, 42 received normal saline injection, and 31 received no injection. In patients receiving bupivacaine compared with no injection, within 30 minutes postbanding there was a significant reduction in pain graded by the patient (P = 0.000002) and by the nurse (P = 0.000005) and a significant reduction in incidence of nausea (P = 0.01) and shaking (P = 0.008). However, in the bupivacaine group compared with the other two groups, at the intervals of 6, 24, and 48 hours postbanding there was no sustained reduction in the severity of pain and no reduction in analgesic requirements or limitation of normal activities. In the week after banding, there was no difference between groups in symptoms of nausea, shaking, lightheadedness, urinary retention, or bleeding. Bupivacaine injection may be useful for reducing pain and associated symptoms long enough to tolerate a trip home from the outpatient department but does not show a sustained effect.

  10. A randomized trial of rubber band ligation with or without injection sclerotherapy in the treatment of piles.

    Science.gov (United States)

    Ackroyd; Dicks; Shorthouse

    1999-07-01

    Rubber band ligation (RBL) is an effective treatment for piles but may be followed by pain and bleeding. It is postulated that the addition of injection sclerotherapy (IS) may reduce these complications. This trial aims to compare the use of RBL alone with RBL + IS in the treatment of piles.  Sixty patients with piles were randomized to RBL alone (n=30) or RBL + IS (n=30). Each patient was given a pro forma on which to record the amount of pain (on a visual analogue scale) and bleeding (none, slight or heavy) for 10 days following treatment. Patients were subsequently asked to describe the overall symptomatic outcome in the 6-week follow-up clinic (worse, same, slightly better, much better). Long-term outcome was ascertained by a telephone survey.  Symptomatic improvement was similar in both groups (median score (range)=1.5 (0-2) vs 2 (0-2); P=NS), and there was no difference in pain (median score (range)=6 (0-77) vs 6 (0-50); P=NS). However, the amount of bleeding was significantly less in the RBL + IS group (median score (range)=3.5 (0-12) vs 0 (0-10); P < 0.001). The long-term outcome was similar in both groups.  The addition of IS to RBL does not affect procedure-related pain or symptomatic outcome, but significantly reduces the risk of post-bleeding.

  11. Comparative study of hemorrhoidectomy and rubber band ligation in treatment of second and third degree hemorrhoids in kashmir.

    Science.gov (United States)

    Gagloo, Mushtaq A; Hijaz, S Wardul; Nasir, S Aijaz; Reyaz, Arjmand; Bakshi, I H; Chowdary, Nisar A; Naqash, Sameer A; Sharief, Banday M

    2013-10-01

    The diagnosis of hemorrhoids is primarily based on the proctoscopic examination. The study evaluates comparative results of rubber band ligation (RBL) and hemorrhoidectomy. This study was conducted over a period of 1½ year from Jan 2003 to June 2004. It includes 100 patients having second- or third-degree primary hemorrhoids who attended surgical OPD of SMHS Hospital Srinagar, Kashmir. These 100 patients were selected randomly and divided into two groups of 50 patients each (hemorrhoidectomy group and RBL group). Each patient was subjected to sigmoidoscopy to exclude other lesion higher up in rectosigmoid. Patients of fissure, fistulae, and malignancy were excluded. All parameters were recorded and finally analysed. The statistical analysis of the study was done using SPSS statistical package in which we used descriptive statistics and correlation analysis for the final evaluation. Hemorrhoidectomy and RBL are equally effective especially in second-degree hemorrhoids. However, RBL should be considered the first-line treatment in second-degree hemorrhoids because being an outpatient procedure, it is cost effective for the patients, saves many a hospital beds for more sick patients, and takes the pressure off the surgical waiting list. Although RBL is not as effective as hemorrhoidectomy in third-degree hemorrhoid, it does improve bleeding and prolapse and is highly recommended for patients who are unfit for surgery or have concurrent disease that contraindicates anesthesia. RBL should be considered as the first-line treatment for second-degree hemorrhoid. However, in the third-degree hemorrhoids, hemorrhoidectomy achieves better results, and RBL is recommend as the first-line treatment for those patients in whom there is contraindication for surgery or anesthesia.

  12. MANAGEMENT OF HUGE ENCEPHALOCELE

    Directory of Open Access Journals (Sweden)

    Rajeev

    2015-11-01

    Full Text Available Among all neural tube defects, encephalocele incidents are 1 in 5000 live births. (1 Newborn with encephalocele may be associated with other congenital malformations. Encephalocele patient’s management pose many challenge to neurosurgeon due to other associated anomalies that may present like ventriculocele, Dandy Walker and Arnold-Chiari malformation, and difficult positioning airway management to anaesthesiologist. We discuss a case of huge encephalocele and its management

  13. Rubber Reclamation

    Science.gov (United States)

    Williams, Kathryn R.

    2007-01-01

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

  14. ERBU, Expanding Rubber Band Universe

    CERN Document Server

    Soares, Domingos

    2015-01-01

    I put forward a simple unidimensional mechanical analogue of the three-dimensional universe models of modern relativistic cosmology. The main goal of the proposal is the appropriate appreciation of the intrinsic relationship between Hubble's law and the homogeneity of expanding relativistic models.

  15. Material Model Research on Rubber Vibration Isolators

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

  16. Adhesion of yeasts and bacteria to fluoro-alkylsiloxane layers chemisorbed on silicone rubber

    NARCIS (Netherlands)

    Everaert, EPJM; van der Mei, HC; Busscher, HJ

    1998-01-01

    Indwelling voice prostheses are most often made of silicone rubber. However, the silicone rubber surface attracts huge quantities of adhering yeasts and bacteria and their colonization on the valve side of voice prostheses leads to frequent malfunctioning. On average, indwelling voice prostheses hav

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

    Science.gov (United States)

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

    2015-02-01

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

  18. Natural rubber: leather composites

    OpenAIRE

    K. Ravichandran; N. Natchimuthu

    2005-01-01

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

  19. 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...

  20. Mechanochemical modification of natural rubber

    Science.gov (United States)

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

    2016-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Abdullah Siti Radziah

    2016-01-01

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

  2. Rubber-band ligation for hemorrhoids in a Colorectal Unit: A prospective study Ligadura con banda elástica de las hemorroides en una Unidad de Coloproctología: Estudio prospectivo

    Directory of Open Access Journals (Sweden)

    J. C. Bernal

    2005-01-01

    Full Text Available Introduction: nowadays the rubber band ligation technique is one of the most worldwide used and effective treatment of the hemorrhoidal disease. Objectives: our study has as a goal to analyze the success or failure of the rubber band ligation in hemorrhoids grade 1,2 and 3, to analyze their complications and to see if all symptomatic hemorrhoids should be treated with ligation at the first visit. Patients and method: a prospective and descriptive study was designed for patients who came to the Colorectal Unit with hemorrhoidal disease from September 1997 to December 2001. First, second and third degree patients were treated according to the classification of hemorrhoids of St. Mark's Hospital. The technique of ligation after Barron was applied. Results: from 261 patients with a mean age of 48.3 (range: 16-86, 181 (99 M/82 W have been treated with Barron's method and 80 with rich fiber diet and water. Rectal bleeding was the most common symptom (91.16%. Anuscopy showed hemorrhoidal disease in all the cases. From 181 patients, 19.33% were hemorrhoids degree I, 51.93% degree II and 29.83% degree III. Two hundred and eighty-seven ligation sessions were done and the balance of ligations per patient was 2.45 and 1.5 rubber band per session. The 32% of the patients referred pain after ligation. A 13.81% of cases were operated due to persistent rectal bleeding or hemorrhoidal prolapse. Conclusions: symptomatic hemorrhoids degree I and II with a short clinical history should be treated initially with a rich fiber and water diet. The technique of Barron is an effective therapy to treat the hemorrhoids degree 1, 2 and in 74% of success in cases with degree 3.Introducción: la técnica de ligaduras con banda para hemorroides constituye hoy en día uno de los tratamientos más efectivos a nivel mundial. Objetivos: el objetivo de nuestro estudio ha sido valorar el éxito/fracaso terapéutico de las ligaduras en hemorroides grado I-II-III, analizar sus

  3. Intelligent Classification in Huge Heterogeneous Data Sets

    Science.gov (United States)

    2015-06-01

    INTELLIGENT CLASSIFICATION IN HUGE HETEROGENEOUS DATA SETS JUNE 2015 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED...To) JUL 2013 – APR 2015 4. TITLE AND SUBTITLE INTELLIGENT CLASSIFICATION IN HUGE HETEROGENEOUS DATA SETS 5a. CONTRACT NUMBER IN-HOUSE 5b. GRANT...signals and through data dimension reduction, and to develop and tailor algorithms for the extraction of intelligence from several huge heterogeneous

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

    Directory of Open Access Journals (Sweden)

    Yong Yu

    2016-06-01

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

  5. Blue rubber bleb naevus

    Directory of Open Access Journals (Sweden)

    Mittal R

    1995-01-01

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

  6. Biodiversity in rubber agroforests

    NARCIS (Netherlands)

    Beukema, Hendrien

    2013-01-01

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

  7. Natural rubber biosynthesis in plants: rubber transferase.

    Science.gov (United States)

    Cornish, Katrina; Xie, Wenshuang

    2012-01-01

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

  8. The Rubber band and the Ruler

    CERN Document Server

    Frère, Jean-Marie

    2016-01-01

    In this short presentation, we address two somewhat separate issues. The first one deals with the establishment (vs discovery) of what we call "physical laws". The discussion runs on a "successive approximations" approach, suited to our own thinking process, and aiming at the "simplest \\emph{possible} formulation ", as opposed to the idea of pre-existing laws to be discovered. In the second part, we review briefly an approach to the (observed) metric originating from a short distance fractal structure, and remind how a symmetrical situation can arise from mere re-summations.

  9. Multilayer graphene rubber nanocomposites

    Science.gov (United States)

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

    2016-05-01

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

  10. Radiation vulcanization of rubbers

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-02-01

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

  11. Global Synethetic Rubber Industrial Outlook

    Institute of Scientific and Technical Information of China (English)

    Dr.Leon Loh

    2011-01-01

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

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

    Science.gov (United States)

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

  13. Study on the behaviour of rubber aggregates concrete beams using analytical approach

    OpenAIRE

    Asutkar, Priyanka; Shinde, S.B.; Patel, Rakesh

    2017-01-01

    Concrete is one the most extensively used construction material all over the world. Many scientists and researchers are in quest for developing alternate construction material that are environment friendly and contribute towards sustainable development. Huge amount of rubber tyres waste is being generated day by day which creates the disposal problem and has many environmental issues. As this scrap rubber waste is an elastic material having less specific gravity, energy absorbent material can...

  14. Runaway Rubber Removal

    Science.gov (United States)

    1989-01-01

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

  15. Outcome of Hepatectomy for Huge Hepatocellular Carcinoma.

    Science.gov (United States)

    Jo, Sungho

    2011-05-01

    In spite of the recent improved results of hepatectomy for huge hepatocellular carcinomas (HCC), the prognosis of patients with huge HCCs is still poor compared to that of patients with small HCCs. This study was performed to compare the results of hepatectomy between patients with huge HCCs and those with small HCCs, to identify the prognostic factors in patients with huge HCCs, and to determine the preoperative selection criteria. We retrospectively analyzed 51 patients who underwent hepatectomy, between July 1994 and February 2009 at Dankook University Hospital. Patients with HCC≥10 cm were classified in large (L) group and others were classified in small (S) group. The clinicopathological features, operative procedures, and postoperative outcome were compared between both groups and various prognostic factors were investigated in group L. Eleven patients were classified in group L. Tumor size, vascular invasion, and tumor stage were higher in group L. Postoperative morbidity was higher in group L, but mortality was not different between the groups. Disease-free survivals were significantly lower in group L than in group S (36.4%, and 24.2% vs. 72.0%, and 44.0% for 1- and 3-year), but overall survival rates were similar in both groups (45.5%, and 15.2% in group L vs. 60.3%, and 41.3% in group S for 3- and 5-year). Presence of satellite nodules was the only prognostic factor in multivariate analysis after surgery for huge HCC. Regardless of tumor size, huge HCCs deserve consideration for surgery in patients with preserved liver function. Furthermore, the effect of surgery could be maximized with appropriate selection criteria, such as huge HCC without satellite nodules.

  16. 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.

  17. News Girls in Physics: Getting girls engaged with physics Schools Lecture: How to explore the universe: the IOP schools lecture series 2009 Elastomobile Competition: Rubber-band vehicles go for gold Congress: Congress celebrates centenary Outreach Programme: Tales of the Stars inspires young children from around the world Physics Olympiad: BPhO selects top students for International Physics Olympiad Mobile Science: Mobile teaching lab visits rural Turkey China: Inspiration and competition in China

    Science.gov (United States)

    2009-07-01

    Girls in Physics: Getting girls engaged with physics Schools Lecture: How to explore the universe: the IOP schools lecture series 2009 Elastomobile Competition: Rubber-band vehicles go for gold Congress: Congress celebrates centenary Outreach Programme: Tales of the Stars inspires young children from around the world Physics Olympiad: BPhO selects top students for International Physics Olympiad Mobile Science: Mobile teaching lab visits rural Turkey China: Inspiration and competition in China

  18. Connecting slow earthquakes to huge earthquakes.

    Science.gov (United States)

    Obara, Kazushige; Kato, Aitaro

    2016-07-15

    Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of their high sensitivity to stress changes in the seismogenic zone. Episodic stress transfer to megathrust source faults leads to an increased probability of triggering huge earthquakes if the adjacent locked region is critically loaded. Careful and precise monitoring of slow earthquakes may provide new information on the likelihood of impending huge earthquakes.

  19. Connecting slow earthquakes to huge earthquakes

    Science.gov (United States)

    Obara, Kazushige; Kato, Aitaro

    2016-07-01

    Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of their high sensitivity to stress changes in the seismogenic zone. Episodic stress transfer to megathrust source faults leads to an increased probability of triggering huge earthquakes if the adjacent locked region is critically loaded. Careful and precise monitoring of slow earthquakes may provide new information on the likelihood of impending huge earthquakes.

  20. Treatment strategies for huge central neurocytomas.

    Science.gov (United States)

    Xiong, Zhong-wei; Zhang, Jian-jian; Zhang, Ting-bao; Sun, Shou-jia; Wu, Xiao-lin; Wang, Hao; You, Chao; Wang, Yu; Zhang, Hua-qiu; Chen, Jin-cao

    2015-02-01

    Central neurocytomas (CNs), initially asymptomatic, sometimes become huge before detection. We described and analyzed the clinical, radiological, operational and outcome data of 13 cases of huge intraventricular CNs, and discussed the treatment strategies in this study. All huge CNs (n=13) in our study were located in bilateral lateral ventricle with diameter ≥5.0 cm and had a broad-based attachment to at least one side of the ventricle wall. All patients received craniotomy to remove the tumor through transcallosal or transcortical approach and CNs were of typical histologic and immunohistochemical features. Adjuvant therapies including conventional radiation therapy (RT) or gamma knife radiosurgery (GKRS) were also performed postoperatively. Transcallosal and transcortical approaches were used in 8 and 5 patients, respectively. Two patients died within one month after operation and 3 patients with gross total resection (GTR) were additionally given a decompressive craniectomy (DC) and/or ventriculoperitoneal shunt (VPS) as the salvage therapy. Six patients received GTR(+RT) and 7 patients received subtotal resection (STR)(+GKRS). Eight patients suffered serious complications such as hydrocephalus, paralysis and seizure after operation, and patients who underwent GTR showed worse functional outcome [less Karnofsky performance scale (KPS) scores] than those having STR(+GKRS) during the follow-up period. The clinical outcome of huge CNs seemed not to be favorable as that described in previous reports. Surgical resection for huge CNs should be meticulously considered to guarantee the maximum safety. Better results were achieved in STR(+GKRS) compared with GTR(+RT) for huge CNs, suggesting that STR(+GKRS) may be a better treatment choice. The recurrent or residual tumor can be treated with GKRS effectively.

  1. Biodesulfurization of rubber materials

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-01-01

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

  2. A Huge Ancient Schwannoma of the Epiglottis.

    Science.gov (United States)

    Lee, Dong Hoon; Kim, Jo Heon; Yoon, Tae Mi; Lee, Joon Kyoo; Lim, Sang Chul

    2016-03-01

    Ancient schwannoma of the epiglottis is extremely rare. The authors report the first case of a patient with a huge ancient schwannoma of the epiglottis. Clinicians should consider the possibility that ancient schwannoma may originate in the epiglottis mimicking the other more frequently observed lesions.

  3. 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.

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

    Institute of Scientific and Technical Information of China (English)

    ZHANG Haibo; GOU Mifeng; LIU Xiaoxing; GUAN Xuemao

    2014-01-01

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

  5. Control of the low-frequency vibrations of elastic metamaterial shafts with discretized arc-rubber layers

    Science.gov (United States)

    Lixia, Li; Anjiang, Cai

    2016-06-01

    We propose a new kind of elastic metamaterial (EM) shaft with discretized arc-shaped rubber layers, which shows excellent low-frequency vibration properties. The band gaps of the shaft structure were analyzed by employing the finite element method. The proposed EM shaft exhibits much lower band gaps than the corresponding structures with the whole rubber ring. Furthermore, the band gaps can be modulated by tuning the arc angle and the number of the arc-shaped rubbers. Additionally, we observed that the first complete band gap tends to disappear when the arc angle of each arc-shaped rubber section is decreased but the arc number remains fixed because the arc angle more strongly affects the rotational stiffness than the transverse stiffness of the rubber layers. This new type of EM shafts could find potential application as a means to control the low-frequency vibrations of rotor shafts in mechanical engineering.

  6. The HubBLe Trial: haemorrhoidal artery ligation (HAL) versus rubber band ligation (RBL) for symptomatic second- and third-degree haemorrhoids: a multicentre randomised controlled trial and health-economic evaluation.

    Science.gov (United States)

    Brown, Steven; Tiernan, Jim; Biggs, Katie; Hind, Daniel; Shephard, Neil; Bradburn, Mike; Wailoo, Allan; Alshreef, Abualbishr; Swaby, Lizzie; Watson, Angus; Radley, Simon; Jones, Oliver; Skaife, Paul; Agarwal, Anil; Giordano, Pasquale; Lamah, Marc; Cartmell, Mark; Davies, Justin; Faiz, Omar; Nugent, Karen; Clarke, Andrew; MacDonald, Angus; Conaghan, Phillip; Ziprin, Paul; Makhija, Rohit

    2016-11-01

    Optimal surgical intervention for low-grade haemorrhoids is unknown. Rubber band ligation (RBL) is probably the most common intervention. Haemorrhoidal artery ligation (HAL) is a novel alternative that may be more efficacious. The comparison of HAL with RBL for the treatment of grade II/III haemorrhoids. A multicentre, parallel-group randomised controlled trial. UK NHS and Personal Social Services. 17 NHS Trusts. Patients aged ≥ 18 years presenting with grade II/III (second- and third-degree) haemorrhoids, including those who have undergone previous RBL. HAL with Doppler probe compared with RBL. Primary outcome - recurrence at 1 year post procedure; secondary outcomes - recurrence at 6 weeks; haemorrhoid severity score; European Quality of Life-5 Dimensions, 5-level version (EQ-5D-5L); Vaizey incontinence score; pain assessment; complications; and cost-effectiveness. A total of 370 participants entered the trial. At 1 year post procedure, 30% of the HAL group had evidence of recurrence compared with 49% after RBL [adjusted odds ratio (OR) = 2.23, 95% confidence interval (CI) 1.42 to 3.51; p = 0.0005]. The main reason for the difference was the number of extra procedures required to achieve improvement/cure. If a single HAL is compared with multiple RBLs then only 37.5% recurred in the RBL arm (adjusted OR 1.35, 95% CI 0.85 to 2.15; p = 0.20). Persistence of significant symptoms at 6 weeks was lower in both arms than at 1 year (9% HAL and 29% RBL), suggesting significant deterioration in both groups over the year. Symptom score, EQ-5D-5L and Vaizey score improved in both groups compared with baseline, but there was no difference between interventions. Pain was less severe and of shorter duration in the RBL group; most of the HAL group who had pain had mild to moderate pain, resolving by 3 weeks. Complications were low frequency and not significantly different between groups. It appeared that HAL was not cost-effective compared with RBL. In the base

  7. A huge presacral Tarlov cyst. Case report.

    Science.gov (United States)

    Ishii, Kazuhiko; Yuzurihara, Masahito; Asamoto, Shunji; Doi, Hiroshi; Kubota, Motoo

    2007-08-01

    Perineural cysts have become a common incidental finding during lumbosacral magnetic resonance (MR) imaging. Only some of the symptomatic cysts warrant treatment. The authors describe the successful operative treatment of a patient with, to the best of their knowledge, the largest perineural cyst reported to date. A 29-year-old woman had been suffering from long-standing constipation and low-back pain. During an obstetric investigation for infertility, the clinician discovered a huge presacral cystic mass. Computed tomography myelography showed the lesion to be a huge Tarlov cyst arising from the left S-3 nerve root and compressing the ipsilateral S-2 nerve. The cyst was successfully treated by ligation of the cyst neck together with sectioning of the S-3 nerve root. Postoperative improvement in her symptoms and MR imaging findings were noted. Identification of the nerve root involved by the cyst wall, operative indication, operative procedure, and treatment of multiple cysts are important preoperative considerations.

  8. From tiny microalgae to huge biorefineries

    OpenAIRE

    Gouveia, L.

    2014-01-01

    Microalgae are an emerging research field due to their high potential as a source of several biofuels in addition to the fact that they have a high-nutritional value and contain compounds that have health benefits. They are also highly used for water stream bioremediation and carbon dioxide mitigation. Therefore, the tiny microalgae could lead to a huge source of compounds and products, giving a good example of a real biorefinery approach. This work shows and presents examples of experimental...

  9. A rare clinic entity: Huge trichobezoar

    Directory of Open Access Journals (Sweden)

    Hidayatullah Hamidi, Dr, MD

    2016-01-01

    Conclusion: Trichobezoars should be suspected in young females with long standing upper abdominal masses; as the possibility of malignancy is not very common in this age group. While USG is inconclusive, trichobezoar can be accurately diagnosed with CT. In patient with huge trichobezoar, laparotomy can be performed firstly because of big size and location of mass, and psychiatric recommendation should be made to prevent relapse of this entity.

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

    Science.gov (United States)

    Mizuno, Ju; In-Nami, Hiroshi

    2011-01-01

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

  11. Residual stresses in rubber formed thermoplastic composites

    NARCIS (Netherlands)

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

    2003-01-01

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

  12. Laparoscopic Management of Huge Cervical Myoma.

    Science.gov (United States)

    Peker, Nuri; Gündoğan, Savaş; Şendağ, Fatih

    To demonstrate the feasibility of laparoscopic management of a huge cervical myoma. Step-by-step video demonstration of the surgical procedure (Canadian Task Force classification III-C). Uterine myoma is the most common benign neoplasm of the female reproductive tract, with an estimated incidence of 25% to 30% at reproductive age [1,2]. Patients generally have no symptoms; however, those with such symptoms as severe pelvic pain, heavy uterine bleeding, or infertility may be candidates for surgery. The traditional management is surgery; however, uterine artery embolization or hormonal therapy using a gonadotropin-releasing hormone agonist or a selective estrogen receptor modulator should be preferred as the medical approach. Surgical management should be performed via laparoscopy or laparotomy; however, the use of laparoscopic myomectomy is being debated for patients with huge myomas. Difficulties in the excision, removal, and repair of myometrial defects, increased operative time, and blood loss are factors keeping physicians away from laparoscopic myomectomy [1,2]. A 40-year-old gravida 0, para 0 woman was admitted to our clinic with complaints of chronic pelvic pain, dyspareunia, and infertility. Her health history was unremarkable. Ultrasonographic examination revealed a 14 × 10-cm myoma in the cervical region. On bimanual examination, an immobile solid mass originating from the uterine cervix and filling the pouch of Douglas was palpated. The patient was informed of the findings, and laparoscopic myomectomy was recommended because of her desire to preserve her fertility. Abdominopelvic examination revealed a huge myoma filling and enlarging the cervix. Myomectomy was performed using standard technique as described elsewhere. A transverse incision was made using a harmonic scalpel. The myoma was fixed with a corkscrew manipulator and enucleated. Once bleeding was controlled, the myoma bed was filled with Spongostan to prevent possible bleeding from leakage

  13. Huge music archives on mobile devices

    DEFF Research Database (Denmark)

    Blume, H.; Bischl, B.; Botteck, M.

    2011-01-01

    The availability of huge nonvolatile storage capacities such as flash memory allows large music archives to be maintained even in mobile devices. With the increase in size, manual organization of these archives and manual search for specific music becomes very inconvenient. Automated dynamic...... and difficult to tackle on mobile platforms. Against this background, we provided an overview of algorithms for music classification as well as their computation times and other hardware-related aspects, such as power consumption on various hardware architectures. For mobile platforms such as smartphones...

  14. Preparation of Hydrogenated Nitrile Rubber

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  15. QENS investigation of filled rubbers

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-07-01

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

  16. 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.)

  17. QENS investigation of filled rubbers

    Science.gov (United States)

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

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

  18. Preparation of Hydrogenated Nitrile Rubber

    Institute of Scientific and Technical Information of China (English)

    LIU; ZhiCai

    2001-01-01

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

  19. Laboratory performance of asphalt rubber mixtures

    OpenAIRE

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

    2009-01-01

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

  20. CRIA Sians A areement with Rubber Valley

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

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

  1. Laparoscopic Management of Huge Myoma Nascendi.

    Science.gov (United States)

    Peker, Nuri; Gündoğan, Savas; Şendağ, Fatih

    To demonstrate the feasibility of laparoscopic management of a huge myoma nascendi. Step-by-step video demonstration of the surgical procedure (Canadian Task Force classification III-C). Uterine myoma is the most common benign neoplasm of the female reproductive tract, with an estimated incidence of 25% to 30% at reproductive age [1,2]. Patients generally have no symptoms; however, those with such symptoms as severe pelvic pain, heavy uterine bleeding, or infertility may be candidates for surgery. The traditional management is surgery; however, uterine artery embolization or hormonal therapy using a gonadotropin-releasing hormone agonist or a selective estrogen receptor modulator should be preferred as the medical approach. Surgical management should be performed via laparoscopy or laparotomy; however, the use of laparoscopic myomectomy is being debated for patients with huge myomas. Difficulties in the excision, removal, and repair of myometrial defects, increased operative time, and blood loss are factors keeping physicians away from laparoscopic myomectomy [1,2]. A 35-year-old woman was admitted to our clinic with complaints of chronic pelvic pain and heavy menstrual bleeding. Her medical history included multiple hospitalizations for blood transfusions, along with a recently measured hemoglobin level of 9.5 g/dL and a hematocrit value of 29%. She had never been married and had no children. Pelvic ultrasonography revealed a 12 × 10-cm uterine myoma located on the posterior side of the corpus uteri and protruding through to the cervical channel. This was a huge intramural submucous myoma in close proximity to the endometrial cavity and spreading through the myometrium. On vaginal examination, the myoma was found to extend into the vagina through the cervical channel. Laparoscopic myomectomy was planned because of the patient's desire for fertility preservation. Abdominopelvic exploration revealed a huge myoma filling the posterior side of the corpus uteri and

  2. Rubber band ligation and infrared photocoagulation for the outpatient treatment of hemorrhoidal disease Ligadura elástica e fotocoagulação com radiação infravermelha no tratamento ambulatorial da doença hemorroidária

    Directory of Open Access Journals (Sweden)

    Maurício Pichler Ricci

    2008-02-01

    Full Text Available PURPOSE: To compare the results of rubber band ligation and infrared photocoagulation for the treatment of hemorrhoidal disease through the analysis of the incidence of complications after each treatment and respective success rate. METHODS: Forty-eight patients with first, second or third degree hemorrhoidal disease were randomized to recieve treatment with either rubber band ligation (n=23 or infrared photocoagulation (n=25. Each patient was assessed at 1 week and 4 week intervals after treatment. We compared the incidence of complications and efficiency of each treatment modality and Qui-square, Fisher's Exact Test and Student's t Test were used to statistical analysis. RESULTS: Bleeding occured in eigth (34,7% patients treated with rubber band ligation and in four (16,0% after infrared photocoagulation (p=0,243. Thirteen (52,0% patients felt pain during infrared photocoagulation and 9 (39,1% after rubber band ligation (p=0,546. After rubber band ligation, 14 (60,8% required medication for pain relief. One patient (4,0% required medication after infrared photocoagulation (pOBJETIVO: Comparar os resultados da ligadura elástica com os da fotocoagulação com radiação infravermelha no tratamento da doença hemorroidária através da análise de suas respectivas morbidades e eficácia. MÉTODOS: Foi realizado ensaio clínico casualisado com 48 pacientes portadores de doença hemorroidária graus I, II e III. Após randomização, os pacientes foram submetidos à ligadura elástica (n=23 ou fotocoagulação com radiação infravermelha (n=25. Os pacientes compareceram para consulta ambulatorial 1 semana e 4 semanas após o procedimento. A avaliação foi feita através da análise da incidência de morbidades após cada procedimento e eficácia, com quatro semanas de acompanhamento. As análises estatísticas foram realizadas através do teste do Qui-quadrado, Teste Exato de Fisher e Teste t de Student. RESULTADOS: Dos pacientes submetidos

  3. Alternative sources of natural rubber

    NARCIS (Netherlands)

    Mooibroek, H.; Cornish, K.

    2000-01-01

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

  4. Warpage of rubber pressed composites

    NARCIS (Netherlands)

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

    2002-01-01

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

  5. Engineered Plastics Containing Recycled Rubber

    Institute of Scientific and Technical Information of China (English)

    Dong Yang Wu

    2000-01-01

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

  6. Huge Tongue Lipoma: A Case Report

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Damghani

    2015-03-01

    Full Text Available Introduction: Lipomas are among the most common tumors of the human body. However, they are uncommon in the oral cavity and are observed as slow growing, painless, and asymptomatic yellowish submucosal masses. Surgical excision is the treatment of choice and recurrence is not expected.    Case Report: The case of a 30-year-old woman with a huge lipoma on the tip of her tongue since 3 years, is presented. She had difficulty with speech and mastication because the tongue tumor was filling the oral cavity. Clinical examination revealed a yellowish lesion, measuring 8 cm in maximum diameter, protruding from the lingual surface. The tumor was surgically excised with restoration of normal tongue function and histopathological examination of the tumor confirmed that it was a lipoma.   Conclusion:  Tongue lipoma is rarely seen and can be a cause of macroglossia. Surgical excision for lipoma is indicated for symptomatic relief and exclusion of associated malignancy.

  7. Galaxies Collide to Create Hot, Huge Galaxy

    Science.gov (United States)

    2009-01-01

    This image of a pair of colliding galaxies called NGC 6240 shows them in a rare, short-lived phase of their evolution just before they merge into a single, larger galaxy. The prolonged, violent collision has drastically altered the appearance of both galaxies and created huge amounts of heat turning NGC 6240 into an 'infrared luminous' active galaxy. A rich variety of active galaxies, with different shapes, luminosities and radiation profiles exist. These galaxies may be related astronomers have suspected that they may represent an evolutionary sequence. By catching different galaxies in different stages of merging, a story emerges as one type of active galaxy changes into another. NGC 6240 provides an important 'missing link' in this process. This image was created from combined data from the infrared array camera of NASA's Spitzer Space Telescope at 3.6 and 8.0 microns (red) and visible light from NASA's Hubble Space Telescope (green and blue).

  8. A rare clinic entity: Huge trichobezoar.

    Science.gov (United States)

    Hamidi, Hidayatullah; Muhammadi, Marzia; Saberi, Bismillah; Sarwari, Mohammad Arif

    2016-01-01

    Trichobezoar is a rare clinical entity in which a ball of hair amasses within the alimentary tract. It can either be found as isolated mass in the stomach or may extend into the intestine. Trichobezoars mostly occur in young females with psychiatric disorders such as trichophagia and trichotillomania. Authors present a giant trichobezoar in an 18year old female presented with complaints of upper abdominal mass, epigastric area pain, anorexia and weight loss. The patient underwent trans-abdominal ultrasonography (USG), Computed tomography (CT), upper gastrointestinal endoscopy and subsequently laparotomy. USG was inconclusive due to non-specific findings. It revealed a thick echogenic layer with posterior dirty shadowing extending from the left sub-diaphragmatic area to the right sub hepatic region obscuring the adjacent structures. Abdominal CT images revealed a huge, well defined, multi-layered, heterogeneous, solid appearing, non-enhancing mass lesion in the gastric lumen extending from the gastric fundus to the pyloric canal. An endoscopic attempt was performed for removal of this intraluminal mass, but due to its large size, and hard nature, the endoscopic removal was unsuccessful. Finally the large trichobezoar was removed with open laparotomy. Trichobezoars should be suspected in young females with long standing upper abdominal masses; as the possibility of malignancy is not very common in this age group. While USG is inconclusive, trichobezoar can be accurately diagnosed with CT. In patient with huge trichobezoar, laparotomy can be performed firstly because of big size and location of mass, and psychiatric recommendation should be made to prevent relapse of this entity. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Rubber compounding and processing

    CSIR Research Space (South Africa)

    John

    2014-06-01

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

  10. 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.

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

    Science.gov (United States)

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

    2012-01-01

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

  12. 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.

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

    NARCIS (Netherlands)

    Sarkawi, S.S.

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-01-01

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

  15. HUBBLE SPIES HUGE CLUSTERS OF STARS FORMED

    Science.gov (United States)

    2002-01-01

    BY ANCIENT ENCOUNTER This stunningly beautiful image [right] taken with the NASA Hubble Space Telescope shows the heart of the prototypical starburst galaxy M82. The ongoing violent star formation due to an ancient encounter with its large galactic neighbor, M81, gives this galaxy its disturbed appearance. The smaller picture at upper left shows the entire galaxy. The image was taken in December 1994 by the Kitt Peak National Observatory's 0.9-meter telescope. Hubble's view is represented by the white outline in the center. In the Hubble image, taken by the Wide Field and Planetary Camera 2, the huge lanes of dust that crisscross M82's disk are another telltale sign of the flurry of star formation. Below the center and to the right, a strong galactic wind is spewing knotty filaments of hydrogen and nitrogen gas. More than 100 super star clusters -- very bright, compact groupings of about 100,000 stars -- are seen in this detailed Hubble picture as white dots sprinkled throughout M82's central region. The dark region just above the center of the picture is a huge dust cloud. A collaboration of European and American scientists used these clusters to date the ancient interaction between M82 and M81. About 600 million years ago, a region called 'M82 B' (the bright area just below and to the left of the central dust cloud) exploded with new stars. Scientists have discovered that this ancient starburst was triggered by the violent encounter with M81. M82 is a bright (eighth magnitude), nearby (12 million light-years from Earth) galaxy in the constellation Ursa Major (the Great Bear). The Hubble picture was taken Sept. 15, 1997. The natural-color composite was constructed from three Wide Field and Planetary Camera 2 exposures, which were combined in chromatic order: 4,250 seconds through a blue filter (428 nm); 2,800 seconds through a green filter (520 nm); and 2,200 seconds through a red (820 nm) filter. Credits for Hubble image: NASA, ESA, R. de Grijs (Institute of

  16. Rubber friction on (apparently) smooth lubricated surfaces

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-27

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

  17. Rubber friction on (apparently) smooth lubricated surfaces

    Science.gov (United States)

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

    2008-02-01

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

  18. Umbilicoplasty in children with huge umbilical hernia

    Directory of Open Access Journals (Sweden)

    Akakpo-Numado Gamedzi Komlatsè

    2014-01-01

    Full Text Available Background: Huge umbilical hernias (HUH are voluminous umbilical hernia (UH that are frequent in black African children. Several surgical techniques are used in their treatment for umbilical reconstruction, but techniques using skin flaps provide better aesthetic results. In this study, we presented our technique of umbilicoplasty in HUH, and its results. Patients and Methods: It is a retrospective study on children treated for HUH, from January 2012 to December 2013. The UH was called HUH when its basis diameter (BD exceeds 3 cm. Every HUH was characterised by its height, BD and morphology. Our technique was a two lateral flaps technique; the flaps are symmetrical and drawn so as to reconstitute the different parts of the umbilicus. The results were appreciated with criteria, including the peripheral ring and the central depression of the neo-umbilicus. Results : Twelve children were concerned (7 boys and 5 girls. Their mean age was 5 years and 6 months. The mean BD was 5.6 cm (extremes 3 and 8 cm, and the mean height of the HUH was 7.45 cm (extremes 3 and 9 cm. All underwent umbilicoplasty. In early post-operative period, two children presented a transitory subcutaneous hematoma. Late complications were granulation tissue with two children, and cheloid scar with one. With a mean follow-up of 10 months, we had 10 excellent results and two fair results according to our criteria. Conclusion: Our two lateral flaps umbilicoplasty is well-adapted to HUH in children. It is simple and assures a satisfactory anatomical and cosmetic result.

  19. Hepatectomy for huge hepatocellular carcinoma: single institute's experience.

    Science.gov (United States)

    Yang, Lianyue; Xu, Jiangfeng; Ou, Dipeng; Wu, Wei; Zeng, Zhijun

    2013-09-01

    The surgical resection of huge hepatocellular carcinoma (HCC) is still controversial. This study was designed to introduce our experience of liver resection for huge HCC and evaluate the safety and outcomes of hepatectomy for huge HCC. A total of 258 hepatic resections for the patients with huge HCC were analysed retrospectively from December 2002 to December 2011. The operative outcomes were compared with 293 patients with HCC >5.0 cm but huge HCC group and HCC >5.0 cm but huge HCC group has significantly a more longer overall and disease-free survival time than nodular huge HCC (P = 0.026, P = 0.022). Univariate and multivariate analysis revealed that the types of tumour, vascular invasion, and UICC stage were independent prognostic factors for overall survival (P = 0.047, P = 0.037, P = 0.033). Hepatic resection can be performed safely for huge HCC with a low mortality and favorable survival outcomes. Solitary huge HCC has the better surgical outcomes than nodular huge HCC.

  20. Rubberized Concrete Durability Against Abrasion

    Directory of Open Access Journals (Sweden)

    Md Noor Nurazuwa

    2016-01-01

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

  1. Silicone-Rubber Stitching Seal

    Science.gov (United States)

    Wang, D. S.

    1985-01-01

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

  2. Superheated rubber for cold storage

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-04-26

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

  3. A novel composite sound absorber with recycled rubber particles

    Science.gov (United States)

    Hong, Zhou; Bo, Li; Guangsu, Huang; Jia, He

    2007-07-01

    A new kind of composite sound absorber has been fabricated, using recycled rubber particles with good attenuation property as sound energy attenuation layer, low characteristic impedance materials such as polymer porous foam or perforated panel as matching layer. Its' attractive characteristics include: low-cost, broad-band sound absorption, thin in thickness and relatively simple processing. An acoustic transmission analytical model is developed and successfully applied to evaluate the sound absorption of the composite absorber.

  4. Identification of stand age in rubber plantations using time series Landsat and PALSAR-2 data

    Science.gov (United States)

    Chen, B.; Wu, Z.; Xiao, X.; Li, X.; Ma, J.; Lan, G.; Yang, C.; Xie, G.; Dong, J.; Qin, Y.

    2016-12-01

    Stand age of rubber plantation is vital for optimal plantation management such as fertilization, prediction of latex yield and timber production. It is also an important variable for biomass estimation and determining the distribution of carbon pools and fluxes in rubber plantation ecosystem. Benefit from the traits of large coverage, high speed, and low-cost, satellite remote sensing techniques have been serviced as a major approach to map acreage and stand age of forest and plantations. Despite a number of studies working on acreage and stand age mapping, the stand age information of rubber plantation is still poorly available at regional scale. In this study, the 25-m cloud-free Phased Array type L-band Synthetic Aperture Radar 2 (PALSAR-2) mosaic product, together with the 30-m time series images of Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI), were used to map stand age of rubber plantation in China under Google Earth Engine computing platform. Rubber plantation in 2015 were first identified by structural information in PALSAR-2 and phenological and spectral signatures (deciduous, rapid change of canopies during rubber defoliation and foliation periods, and dense canopy in growing season) that derived from time series Landsat ETM+/OLI images. Based on the resultant rubber plantation map, we then successfully identified the stand age of rubber plantation using land cover transfer information during rubber seeding cultivation period, specifically, by yearly composited Land Surface Water Index (LSWI) of Landsat TM/ETM+/OLI images since 1985. The estimated stand age has very high accuracy with Root Square Mean Error (RMSE) less than 2 years. The resultant rubber stand age information are likely to be useful for sustainable plantation management and ecological assessment, and the methodology can be extendable for applications in other regions.

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

    Science.gov (United States)

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

    2017-06-01

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

  6. THERMAL CONDUCTIVITY OF RUBBERIZED GYPSUM BOARD

    Directory of Open Access Journals (Sweden)

    Taher Abu-Lebdeh

    2014-01-01

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

  7. Natural rubber latex allergy

    Directory of Open Access Journals (Sweden)

    Deval Ravi

    2008-01-01

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

  8. Effect of Ingredient Loading on Surface Migration Kinetics of Additives in Vulcanized Natural Rubber Compounds

    Directory of Open Access Journals (Sweden)

    Bryan B. Pajarito

    2014-12-01

    Full Text Available Surface migration kinetics of chemical additives in vulcanized natural rubber compounds were studied as function of ingredient loading. Rubber sheets were compounded according to a 212-8 fractional factorial design of experiment, where ingredients were treated as factors varied at two levels of loading. Amount of migrated additives in surface of rubber sheets was monitored through time at ambient conditions. The maximum amount and estimated rate of additive migration were determined from weight loss kinetic curves. Attenuated total reflection–Fourier transform infrared (ATR-FTIR spectroscopy and optical microscopy were used to characterize the chemical structure and surface morphology of sheet specimens during additive migration. ANOVA results showed that increased loading of reclaimed rubber, CaCO3, and paraffin wax signif icantly decreased the maximum amount of additive migration; by contrast, increased loading of used oil, asphalt, and mercaptobenzothiazole disulphide (MBTS increased the maximum amount. Increased loading of sulfur, diphenylguanidine (DPG, and paraffin wax significantly decreased the additive migration rate; increased loading of used oil, asphalt, and stearic acid elicited an opposite effect. Comparison of ATRFTIR spectra of migrated and cleaned rubber surfaces showed signif icant variation in intensity of specif ic absorbance bands that are also present in infrared spectra of migrating chemicals. Paraffin wax, used oil, stearic acid, MBTS, asphalt, and zinc stearate were identified to bloom and bleed in the rubber sheets. Optical micrographs of migrated rubber surfaces revealed formation of white precipitates due to blooming and of semi-transparent wet patches due to bleeding.

  9. Isoprene Rubber Has Broad Market Potential

    Institute of Scientific and Technical Information of China (English)

    Xu Qingsbeng

    2007-01-01

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

  10. 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...

  11. Advances in rubber/halloysite nanotubes nanocomposites.

    Science.gov (United States)

    Jia, Zhixin; Guo, Baochun; Jia, Demin

    2014-02-01

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

  12. A Case of Huge Retroperitoneal Ganglioneuroma

    Directory of Open Access Journals (Sweden)

    Ali Akbarzadeh Pasha

    2009-01-01

    performed and histopathologic examination confirmed ganglioneuroma. "nDiscussion: Ganglioneuromas are tumors of adolescents and young adults (40-60%. The mean age of occurrence is 7 years. The female to male ratio is 1.5:1. They are considered to be mature tumors and do not have immature elements such as neuroblasts and mitotic activity. The presence of neuroblasts automatically makes the tumor a ganglioneuroblastoma or neuroblastoma, thereby excluding the diagnosis of ganglioneuroma. These neoplasms are rarely larger than 10 cm in diameter. About 30-50% of ganglioneuromas are retroperitoneal and 40% originate in the posterior mediastinum. Roughly 20% of these tumors occur in the adrenal medulla. Cervical lesions constitute only 10% of the cases. "nGanglioneuromas are usually asymptomatic regardless of their size and they are typically discovered on a routine radiograph. These tumors may be hormonally active. Metastasis is rare and the bone is the most common site. US of ganglioneuroma shows a homogeneous, hypoechoic,well-circumscribed mass. CT scan is the imaging modality that is most commonly used to evaluate these tumors. CT scan shows a well-defined mass with punctate calcification in 20% of cases that  tend to grow around major blood vessels but the blood flow remains normal. Nonenhanced CT reveals a homogeneous mass with less attenuation than the muscle. "n  "nGanglioneuromas appear homogeneous on MRI and have relatively low signal intensity on T1. They have characteristic curvilinear bands of low signal intensity on T2; these bands are collagen fibers and intertwined bundles of schwann cells. Low-signal ring is seen in both T1 and T2 images. Ganglioneuroma can accumulate MIBG .Overall, patients with ganglioneuroma have a favorable prognosis. Low-risk tumors are usually treated with surgical resection only. Treatment with chemotherapy before surgery may be indicated in high risk tumors.  

  13. Radiation Induced Grafting of Acrylate onto Waste Rubber: The Effect of Monomer Type

    Directory of Open Access Journals (Sweden)

    Shirajuddin Siti Salwa M.

    2017-01-01

    Full Text Available The effect of three different acrylate group monomers, namely n-butyl acrylate, methacrylic acid and tripropylene glycol diacrylate of radiation induced grafting onto waste rubber was studied. The electron beam accelerator operated at voltage of 2MeV was used to irradiate the waste rubber at 10 kGy and 100 kGy absorbed radiation dose, respectively. The formation of grafting was observed from the increase in the grafting yield and confirmed by Transformed Infra-Red Spectroscopy results. According to the result obtained, only tripropylene glycol diacrylate was selected to graft onto waste rubber. The carbonyl bond from acrylate groups was seen at 1726 cm-1 band which confirmed the presence of TPGDA in the polymer matrix. This indicates the successful preparation of the TPGDA-grafted waste rubber via radiation induced grafting techniques.

  14. Optimization of Dynamically Generated SQL Queries for Tiny-Huge, Huge-Tiny Problem

    Directory of Open Access Journals (Sweden)

    Arjun K Sirohi

    2013-03-01

    Full Text Available In most new commercial business software applications like Customer Relationship Management, the datais stored in the database layer which is usually a Relational Database Management System (RDBMS likeOracle, DB2 UDB or SQL Server. To access data from these databases, Structured Query Language (SQLqueries are used that are generated dynamically at run time based on defined business models and businessrules. One such business rule is visibility- the capability of the application to restrict data access based onthe role and responsibility of the user logged in to the application. This is generally achieved by appendingsecurity predicates in the form of sub-queries to the main query based on the roles and responsibility of theuser. In some cases, the outer query may be more restrictive while in other cases, the security predicatesmay be more restrictive. This often results in a dilemma for the cost-based optimizer (CBO of the backenddatabase whether to drive from the outer query or drive from the security predicate sub-queries. Thisdilemma is sometimes called the “Tiny-Huge, Huge-Tiny” problem and results in serious performancedegradation by way of increased response times on the application User Interface (UI. This paperprovides a case study of a new approach to vastly reduce this CBO dilemma by a combination of denormalizedcolumns and re-writing of the security predicates’ sub-queries at run-time, thereby levelling theouter and security sub-queries. This approach results in more stable execution plans in the database andmuch better performance of such SQLs, effectively leading to higher performance and scalability of theapplication.

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

    OpenAIRE

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

    2016-01-01

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

  16. 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...

  17. 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.

  18. Involvement of two latex-clearing proteins during rubber degradation and insights into the subsequent degradation pathway revealed by the genome sequence of Gordonia polyisoprenivorans strain VH2.

    Science.gov (United States)

    Hiessl, Sebastian; Schuldes, Jörg; Thürmer, Andrea; Halbsguth, Tobias; Bröker, Daniel; Angelov, Angel; Liebl, Wolfgang; Daniel, Rolf; Steinbüchel, Alexander

    2012-04-01

    The increasing production of synthetic and natural poly(cis-1,4-isoprene) rubber leads to huge challenges in waste management. Only a few bacteria are known to degrade rubber, and little is known about the mechanism of microbial rubber degradation. The genome of Gordonia polyisoprenivorans strain VH2, which is one of the most effective rubber-degrading bacteria, was sequenced and annotated to elucidate the degradation pathway and other features of this actinomycete. The genome consists of a circular chromosome of 5,669,805 bp and a circular plasmid of 174,494 bp with average GC contents of 67.0% and 65.7%, respectively. It contains 5,110 putative protein-coding sequences, including many candidate genes responsible for rubber degradation and other biotechnically relevant pathways. Furthermore, we detected two homologues of a latex-clearing protein, which is supposed to be a key enzyme in rubber degradation. The deletion of these two genes for the first time revealed clear evidence that latex-clearing protein is essential for the microbial utilization of rubber. Based on the genome sequence, we predict a pathway for the microbial degradation of rubber which is supported by previous and current data on transposon mutagenesis, deletion mutants, applied comparative genomics, and literature search.

  19. Blue rubber bleb naevus syndrome

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  20. Scarless surgery for a huge liver cyst: A case report.

    Science.gov (United States)

    Kashiwagi, Hiroyuki; Kawachi, Jun; Isogai, Naoko; Ishii, Masanori; Miyake, Katsunori; Shimoyama, Rai; Fukai, Ryota; Ogino, Hidemitsu

    2017-09-01

    Symptomatic or complicated liver cysts sometimes require surgical intervention and laparoscopic fenestration is the definitive treatment for these cysts. We performed minimally invasive surgery, hybrid natural orifice transluminal endoscopic surgery (NOTES) without scarring, for a huge liver cyst. An 82-year-old female presented with a month-long history of right upper abdominal pain. We diagnosed her condition as a huge liver cyst by morphological studies. She denied any history of abdominal trauma. Her serum CEA and CA19-9 were normal and a serum echinococcus serologic test was negative. Laparoscopic fenestration, using a hybrid NOTES procedure via a transvaginal approach, was performed for a huge liver cyst because we anticipated difficulty with an umbilical approach, such as single incision laparoscopic surgery (SILS). Her post-operative course was uneventful and she was discharged from our hospital three days after surgery. Pain killers were not required during and after hospitalization. No recurrence of the liver cyst or bulging was detected by clinical examination two years later. A recent trend of laparoscopic procedure has been towards minimizing the number of incisions to achieve less invasiveness. This hybrid NOTES, with a small incision for abdominal access, along with vaginal access, enabled painless operation for a huge liver cyst. We report a huge liver cyst treated by hybrid NOTES. This approach is safe, less invasive, and may be the first choice for a huge liver cyst. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Effect of urea deproteinization on catalytic hydrogenation of natural rubber latex

    Science.gov (United States)

    Cifriadi, A.; Chalid, M.; Puspitasari, S.

    2017-07-01

    Natural rubber is unsaturated biopolymer which has low resistance to heat, oxygen, and ozone. Chemical modification of natural rubber by catalytic hydrogenation can improve its oxidative property. In this study, the catalytic hydrogenation of natural rubber was investigated in latex phase after reduction of protein content with urea. Hydrogenation of deproteinized natural rubber latex was performed by using diimide which generated insitu from hydrazine hydrate/hydrogen peroxide and catalyst (boric acid, cupric sulfate and cupric acetate) at 70°C for 5 h. The hydrogenation system was stabilized with sodium dodecyl sulphate. The hydrogenation of deproteinized natural rubber (HDPNR) was confirmed by FTIR analysis. The result indicated that cupric sulphate was extremely active catalyst which was showed by the elimination of C=C transmittance bands at 1660 cm-1 on HDPNR spectra and highest degree of hydrogenation. Furthermore, urea deproteinization increased possibility of side reactions during catalytic hydrogenation as seen on the reduction of gel content compared to undeproteinized natural rubber.

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

    Science.gov (United States)

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

    2013-05-01

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

  3. Teach Deflection Concepts with Hacksaw Blades and Rubber Bands

    Science.gov (United States)

    Roman, Harry T.

    2013-01-01

    Technology and engineering educators can use a simple hacksaw blade to help students learn about deflection, as that which occurs in a beam. Here the beam is fixed at one end and allowed to deflect in a manner that is easy to see and measure--the hacksaw blade represents a cantilever, an overhanging structure. This simple and very inexpensive…

  4. Thermomechanical characterisation of cellular rubber

    Science.gov (United States)

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

    2016-09-01

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

  5. 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.

  6. 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.

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

    OpenAIRE

    Wassa Ruayruay; Sureurg Khongtong

    2014-01-01

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

  8. VULCANIZATION KINETICS OF SILICONE RUBBER

    Institute of Scientific and Technical Information of China (English)

    YUAN Qiang; LI Yufu; LI Guangliang

    1988-01-01

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

  9. Chemistry of rubber processing and disposal.

    Science.gov (United States)

    Bebb, R L

    1976-10-01

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

  10. 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.

  11. A case of a huge gastroepiploic arterial aneurysm.

    Science.gov (United States)

    Ikeda, Hirokuni; Takeo, Masahiko; Mikami, Ryuuichi; Yamamoto, Mistuo

    2015-08-05

    An 85-year-old man complaining of vague abdominal discomfort was admitted to our hospital. A pulsatile 8 × 7-cm mass in the right upper abdomen was noticed on clinical examination. Computed tomography of the abdomen showed a huge arterial aneurysm in the right gastroepiploic artery, and the left gastroepiploic artery was meandering and expanding. An image diagnosis of gastroepiploic arterial aneurysm (GEAA) was made. Because of the huge size of the aneurysm and the predicted high risk of perforation, surgical intervention was planned. The aneurysm was identified in the greater curve and was found to adhere firmly to the transverse colon. Partial resection of the stomach, aneurysmectomy and partial resection of the transverse colon were performed. Clinically, splanchnic arterial aneurysms are rare. Among them, GEAA is especially rare. We report a rare case of a huge GEAA that was treated successfully by surgery. Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author 2015.

  12. Microstrip microwave band gap structures

    Indian Academy of Sciences (India)

    V Subramanian

    2008-04-01

    Microwave band gap structures exhibit certain stop band characteristics based on the periodicity, impedance contrast and effective refractive index contrast. These structures though formed in one-, two- and three-dimensional periodicity, are huge in size. In this paper, microstrip-based microwave band gap structures are formed by removing the substrate material in a periodic manner. This paper also demonstrates that these structures can serve as a non-destructive characterization tool for materials, a duplexor and frequency selective coupler. The paper presents both experimental results and theoretical simulation based on a commercially available finite element methodology for comparison.

  13. Chemical modifications of liquid natural rubber

    Science.gov (United States)

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

    2016-11-01

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

  14. Malaria-associated rubber plantations in Thailand.

    Science.gov (United States)

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

    2013-01-01

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

  15. Study on the behaviour of rubber aggregates concrete beams using analytical approach

    Directory of Open Access Journals (Sweden)

    Priyanka Asutkar

    2017-02-01

    Full Text Available Concrete is one the most extensively used construction material all over the world. Many scientists and researchers are in quest for developing alternate construction material that are environment friendly and contribute towards sustainable development. Huge amount of rubber tyres waste is being generated day by day which creates the disposal problem and has many environmental issues. As this scrap rubber waste is an elastic material having less specific gravity, energy absorbent material can be used as a replacement material for obtaining lightweight concrete. In present study an attempt is made to partially replace the rubber aggregates by coarse aggregates in concrete and to study its impact on properties of concrete. A modified concrete is prepared by replacing coarse aggregates in concrete with rubber aggregates by varying the replacement proportion from 0% to 20% with increment of 5%. 3 cubes for each percentage of replacement are casted and tested after 28th days of curing. The physiomechanical properties like density, compressive strength and elastic properties of modified concrete are determined from concrete cubes experimentally and further stresses and displacement at every 50 mm depth of beams are determined analytically by method of initial functions (MIF. MIF is an analytical method in which elastic properties and theoretical loads are used to analyse the beams without conducting any experimental programme. The analytical results by MIF are compared with bending theory.

  16. Anaesthetic management in a case of huge plunging ranula.

    Science.gov (United States)

    Sheet, Jagabandhu; Mandal, Anamitra; Sengupta, Swapnadeep; Jana, Debaleena; Mukherji, Sudakshina; Swaika, Sarbari

    2014-01-01

    Plunging ranula is a rare form of mucous retention cyst arising from submandibular and sublingual salivary glands, which may occasionally become huge occupying the whole of the floor of the mouth and extending into the neck, thus, restricting the neck movement as well as disfiguring the normal airway anatomy. Without fiberoptic assistance, blind or retrograde nasal intubation remains valuable choices in this type of situation. Here, we present a case of successful management of airway by blind nasal intubation in a patient posted for excision of a huge plunging ranula.

  17. Huge Gastric Teratoma in an 8-Year Old Boy.

    Science.gov (United States)

    Sisodiya, Rajpal S; Ratan, Simmi K; Man, Parveen K

    2016-01-01

    Gastric teratoma is very rare tumor and usually presents in early infancy. An 8-year-old boy presented with a huge mass in abdomen extending from epigastrium to the pelvis. Ultrasound and CT scan of abdomen revealed a huge mass with solid and cystic components and internal calcifications. The preoperative diagnosis was a teratoma but not specifically gastric one. At operation, it was found to be gastric teratoma. The mass was excised completely with part of the stomach wall. The histopathology confirmed it to be mature gastric teratoma. The rarity of the teratoma with delayed presentation prompted us to report the case.

  18. Anaesthetic challenges in a patient presenting with huge neck teratoma

    Directory of Open Access Journals (Sweden)

    Gaurav Jain

    2013-01-01

    Full Text Available Paediatric airway management is a great challenge even for an experienced anaesthesiologist. Difficult airway in huge cervical teratoma further exaggerates the complexity. This case report is intended at describing the intubation difficulties that were confronted during the airway management of a three year old girl presenting with huge neck teratoma and respiratory distress. This patient was successfully intubated with uncuffed endotracheal tubes in second attempt under inhalational anaesthesia with halothane and spontaneous ventilation. This case exemplifies the importance of careful preoperative workup of an anticipated difficult airway in paediatric patients with neck swelling to minimize any perioperative complications.

  19. Huge pelvic mass secondary to wear debris causing ureteral obstruction.

    Science.gov (United States)

    Hananouchi, Takehito; Saito, Masanobu; Nakamura, Nobuo; Yamamoto, Tetsuya; Yonenobu, Kazuo

    2005-10-01

    We report an unusual granulomatous reaction of wear debris that produced a huge pelvic mass causing ureteral obstruction. A 72-year-old woman, who received a cemented total hip arthroplasty 30 years ago, was referred to the department of gynecology for examination of a pelvic mass. A computed tomography scan revealed a huge homogenous mass, measuring approximately 20 x 16 x 12 cm, including extensive osteolysis of the left pelvis around the acetabular component. Intravenous pyelogram revealed complete obstruction of the left ureter resulting in hydronephrosis of the left kidney. Histological examination from the biopsy specimen detected polyethylene wear debris in the mass.

  20. Anaesthetic management in a case of huge plunging ranula

    Science.gov (United States)

    Sheet, Jagabandhu; Mandal, Anamitra; Sengupta, Swapnadeep; Jana, Debaleena; Mukherji, Sudakshina; Swaika, Sarbari

    2014-01-01

    Plunging ranula is a rare form of mucous retention cyst arising from submandibular and sublingual salivary glands, which may occasionally become huge occupying the whole of the floor of the mouth and extending into the neck, thus, restricting the neck movement as well as disfiguring the normal airway anatomy. Without fiberoptic assistance, blind or retrograde nasal intubation remains valuable choices in this type of situation. Here, we present a case of successful management of airway by blind nasal intubation in a patient posted for excision of a huge plunging ranula. PMID:25886120

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

    OpenAIRE

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

    2006-01-01

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

  2. Imaging of huge lingual thyroid gland with goitre

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.C.; Chen, C.Y.; Chen, F.H.; Lee, G.W.; Hsiao, H.S. [Nat. Defense Medical Centre, Taipei (Taiwan, Province of China). Dept. of Diagnostic Radiol.; Zimmermann, R.A. [Department of Radiology, The Children`s Hospital of Philadelphia, 34th St. and Civic Blvd., Philadelphia, PA 19014 (United States)

    1998-05-01

    We present the CT and MRI findings in a 75-year-old woman with a huge pathologically proven lingual thyroid which underwent goitrous degeneration. CT and MRI showed a midline, tongue-based, exophytic mass with areas of necrosis and heterogeneous contrast enhancement, as seen in large goitres in the normal thyroid gland. (orig.) With 1 fig., 7 refs.

  3. Smart Cities as Support and Legacy of Huge Sport Events

    Directory of Open Access Journals (Sweden)

    TAURION, C.

    2012-12-01

    Full Text Available In this paper we discuss the concept of a smart city and the importance of huge Sport events as an incentive to the creation of the infrastructure necessary for the development of cities that provide quality of life for all its citizens using information technology.

  4. The big, large and huge case of state-building

    DEFF Research Database (Denmark)

    Harste, Gorm

      Using communication theory as point of departure, it is not evident how to study macro phenomena. Michel Foucault limited his studies to a non-Grand Theory when studying discursive events. At the same time, Charles Tilly wrote about Big Structures, Large Processes, Huge Comparisons when trying...

  5. [Experience of surgical treatment of huge mediastinal tumors].

    Science.gov (United States)

    Li, Yuanbo; Zhang, Yi; Xu, Qingsheng; Su, Lei; Zhi, Xiuyi; Wang, Ruotian; Qian, Kun; Hu, Mu; Liu, Lei

    2014-09-23

    The diagnosis and surgical treatment of 36 huge mediastinal tumors were summarized in order to evaluate the effect and safety of the operation. Thirty-six huge mediastinal tumor patients treated in our department from June 2006 to June 2013 were retrospective analyzed, of whom clinical manifestations, diagnosis, surgical treatment and prognosis were carefully collected. Twenty-three cases were men and 13 were women. The average age was 39.2 years old. The pathology turned out to be benign in 23 cases and malignant in 13 cases. Complete resection was achieved in 34 cases while palliative resection in 2 cases with no perioperative death. Six cases had developed postoperative complications but all recovered after active treatment. Patients who had been diagnosed with benign tumors were all alive after follow-up periods of 6 months to 7 years. Nine malignat tumor patients developed recurrence or metastasis, including seven deaths. Surgery played a vital role in the diagnosis and treatment of huge mediastinal tumors. Preoperative diagnosis, accurate surgical approach and careful operation were the key to successful treatment. Benign huge mediastinal tumors had excellent prognosis with surgery.

  6. A Huge Ovarian Dermoid Cyst: Successful Laparoscopic Total Excision.

    Science.gov (United States)

    Uyanikoglu, Hacer; Dusak, Abdurrahim

    2017-08-01

    Giant ovarian cysts, ≥15 cm in diameter, are quite rare in women of reproductive age. Here, we present a case of ovarian cyst with unusual presentation treated by laparoscopic surgery. On histology, mass was found to be mature cystic teratoma. The diagnostic and management challenges posed by this huge ovarian cyst were discussed in the light of the literature.

  7. Huge mediastinal liposarcoma resected by clamshell thoracotomy: a case report.

    Science.gov (United States)

    Toda, Michihito; Izumi, Nobuhiro; Tsukioka, Takuma; Komatsu, Hiroaki; Okada, Satoshi; Hara, Kantaro; Ito, Ryuichi; Shibata, Toshihiko; Nishiyama, Noritoshi

    2017-12-01

    Liposarcoma is the single most common soft tissue sarcoma. Because mediastinal liposarcomas often grow rapidly and frequently recur locally despite adjuvant chemotherapy and radiotherapy, they require complete excision. Therefore, the feasibility of achieving complete surgical excision must be carefully considered. We here report a case of a huge mediastinal liposarcoma resected via clamshell thoracotomy. A 64-year-old man presented with dyspnea on effort. Cardiomegaly had been diagnosed 6 years previously, but had been left untreated. A computed tomography scan showed a huge (36 cm diameter) anterior mediastinal tumor expanding into the pleural cavities bilaterally. The tumor comprised mostly fatty tissue but contained two solid areas. Echo-guided needle biopsies were performed and a diagnosis of an atypical lipomatous tumor was established by pathological examination of the biopsy samples. Surgical resection was performed via a clamshell incision, enabling en bloc resection of this huge tumor. Although there was no invasion of surrounding organs, the left brachiocephalic vein was resected because it was circumferentially surrounded by tumor and could not be preserved. The tumor weighed 3500 g. Pathologic examination of the resected tumor resulted in a diagnosis of a biphasic tumor comprising dedifferentiated liposarcoma and non-adipocytic sarcoma with necrotic areas. The patient remains free of recurrent tumor 20 months postoperatively. Clamshell incision provides an excellent surgical field and can be performed safely in patients with huge mediastinal liposarcomas.

  8. EPDM Rubber Reclaim from Devulcanized EPDM

    NARCIS (Netherlands)

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

    2006-01-01

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

  9. 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

  10. 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....

  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 m

  12. Biorefinery of proteins from rubber plantation residues

    NARCIS (Netherlands)

    Widyarani, R.

    2016-01-01

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

  13. Rheological testing of crumb rubber modified bitumen

    CSIR Research Space (South Africa)

    Mturi, GAJ

    2011-08-01

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

  14. Biorefinery of proteins from rubber plantation residues

    NARCIS (Netherlands)

    Widyarani, R.

    2016-01-01

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

  15. Better Tomorrow of China Rubber Chemicals Industry

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

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

  16. Zinc leaching from tire crumb rubber.

    Science.gov (United States)

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

    2012-12-04

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

  17. Amino acid modifiers in guayule rubber compounds

    Science.gov (United States)

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

  18. Characterization of crumbe rubber and modified asphalt from brazilian petroleum; Caracterizacao de borracha de pneu moido e de asfalto modificado oriundo de petroleo brasileiro

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Expedito F. dos; Feitosa, Judith P.A. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica]. E-mail: judith@dqoi.ufc.br, expeditoflavio@uol.com.br; Soares, Jorge B. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Engenharia de Transporte; Leite, Leni F.M. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2003-07-01

    Initially it was made an evaluation of the thermal behavior, grain composition and elastomer content of a crumb rubber sample. It was verified a thermal resistance of the crumb rubber and an elastomer content ranging from 56 to 68 %. The asphalt binders were obtained from Brazilian CAP (Fazenda Alegre, State of Espirito Santo) and blended with crumb rubber from 2 to 22 %. The asphalt binder presented smaller penetration than pure CAP. The pure asphalt and binder was aged by the RTFOT system. It was observed a C=O band due oxidation. In the asphalt binder with 2 and 5 % of crumb rubber was verified a smaller effect of the oxygen than in the pure asphalt, which suggests larger aging resistance. Apparent viscosity analysis showed that the pure asphalt has a Newtonian behavior in temperature higher than 150 deg C, while a pseudoplastic behavior of the asphalt binder increases with crumb rubber concentration. (author)

  19. 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.

  20. Lignocellulosic fiber reinforced rubber composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

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

  1. Estimation of Carbon Storage in Para Rubber Plantation in Eastern Thailand

    Science.gov (United States)

    Charoenjit, K.; Zuddas, P.; Allemand, P.

    2012-12-01

    This study aims to estimate the carbon stock and sequestration in Para rubber plantation of East Thailand using the THAICHOTE (Thailand Earth Observation System data). For that purpose we identify the area of every stage class Para rubber plantation by the analysis of different image objects (i.e., rule base and multiple regression classifications) and we map the carbon stock and sequestration of each Para rubber class using biomass allometric regressions and carbon content equations. THAICHOTE data include Multispectral image (4 bands at 15x15 m spatial resolution), Panchromatic image (2x2 m spatial resolution) and Stereo image, data acquisition from December 2011-April 2012. The preliminary investigated area is located in Wangchun, (Eastern, Thailand) and covers about 20 Km2. Calibrating the class stage, by image analysis that integrated edge-based segmentation, reflectance, remote sensing indices, texture analysis and canopy height model (CHM), we found that best classification was obtained by multiple regression (accuracy of 80%) compared to rule base logical operation (accuracy 70%) suggesting that manual 3D stereo measurements or Light Detection And Ranging (LiDAR) both are able to construct the CHM. The results of this study indicate that for a total Para rubber biomass of 14,651 tons, the amount of stored carbon is of 7,326 tons. Mature stage of Para rubber plantations exhibits the highest capacity of sequestering with a global flux of 0.21 tons C/ Km2/year.

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

    Science.gov (United States)

    Buranov, Anvar U; Elmuradov, Burkhon J

    2010-01-27

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

  3. Huge uterine-cervical diverticulum mimicking as a cyst

    Directory of Open Access Journals (Sweden)

    S Chufal

    2012-01-01

    Full Text Available Here we report an incidental huge uterine-cervical diverticulum from a total abdominal hysterectomy specimen in a perimenopausal woman who presented with acute abdominal pain. The diverticulum was mimicking with various cysts present in the lateral side of the female genital tract. Histopathological examination confirmed this to be a cervical diverticulum with communication to uterine cavity through two different openings. They can attain huge size if left ignored for long duration and present a diagnostic challenge to clinicians, radiologists, as well as pathologists because of its extreme rarity. Therefore, diverticula should also be included as a differential diagnosis. Its histopathological confirmation also highlights that diverticula can present as an acute abdomen, requiring early diagnosis with appropriate timely intervention. Immunohistochemistry CD 10 has also been used to differentiate it from a mesonephric cyst.

  4. Huge uterine-cervical diverticulum mimicking as a cyst.

    Science.gov (United States)

    Chufal, S; Thapliyal, Naveen; Gupta, Manoj; Pangtey, Nirmal

    2012-01-01

    Here we report an incidental huge uterine-cervical diverticulum from a total abdominal hysterectomy specimen in a perimenopausal woman who presented with acute abdominal pain. The diverticulum was mimicking with various cysts present in the lateral side of the female genital tract. Histopathological examination confirmed this to be a cervical diverticulum with communication to uterine cavity through two different openings. They can attain huge size if left ignored for long duration and present a diagnostic challenge to clinicians, radiologists, as well as pathologists because of its extreme rarity. Therefore, diverticula should also be included as a differential diagnosis. Its histopathological confirmation also highlights that diverticula can present as an acute abdomen, requiring early diagnosis with appropriate timely intervention. Immunohistochemistry CD 10 has also been used to differentiate it from a mesonephric cyst.

  5. A case of huge primary liposarcoma in the liver

    Institute of Scientific and Technical Information of China (English)

    Liang-Mou Kuo; Hong-Shiue Chou; Kun-Ming Chan; Ming-Chin Yu; Wei-Chen Lee

    2006-01-01

    Primary liver liposarcoma is a rare disease. Because of its rarity, the knowledge of the clinical course, management, and prognosis of primary liver liposarcoma are all limited for clinicians. A 61-year-old female patient who suffered from a huge primary liposarcoma in the central portion of the liver had the clinical presentations of fever, nausea, vomiting, jaundice, and body weight loss.The huge tumor was resected successfully. However,the tumor recurred repeatedly and she had repeated hepatectomies to remove the tumor. Thetumor became aggravating after repeated surgeries. Eventually, the patient had cervical spinal metastasis of liposarcoma and she survived for 26 months after liver liposarcoma was diagnosed. Although the tumor may become aggravating after repeated surgeries, repeated hepatectomies are still the best policy to achieve a long-term survival for the patients.

  6. Black Hole Firewalls Require Huge Energy of Measurement

    CERN Document Server

    Hotta, Masahiro; Funo, Ken

    2013-01-01

    The unitary moving mirror model is one of the best quantum systems for checking the reasoning of the firewall paradox in quantum black holes. The reasoning of Almheiri et al. inevitably raises a firewall paradox in the model. We resolve this paradox from the viewpoint of the energy cost of quantum measurements. No firewall with a deadly, huge energy flux appears, as long as the energy for the measurement is much smaller than the ultraviolet cutoff scale.

  7. Severe microphthalmos with cyst and unusually huge dermolipoma.

    Science.gov (United States)

    Li, Weidong; Zhang, Ping; Chen, Qiwen; Ye, Xuelian; Li, Jianqun; Yan, Jianhua

    2015-03-01

    The purpose of this study was to report an unusual case of severe microphthalmos, together with an orbital cyst and huge ocular surface dermolipoma. This is a clinical report relating clinical features as well as imaging and histopathologic findings, along with surgical management of the patient. A 5-month-old Chinese male infant was referred, with 2 large masses in the left eye that were present since birth. Ocular examination results revealed a complete absence of any eye structures in the left orbit. In its place were 2 large masses between the left upper and lower palpebral fissure. One was a 3 × 3 × 2.5-cm spherical red tumor with a smooth surface. The other was a large solid spherical tumor, 4 × 4 × 5 cm, covered with normal skin located in the temporal region and attached to the red mass by a pedicle. Orbital magnetic resonance imaging examination findings confirmed that no eye structures were present in the left orbit. However, a cystic lesion was found in the left orbit, with a low signal on T1-weighted imaging and high signal on T2-weighted imaging, and another huge spherical heterogeneous mass was located "outside" the left orbit. Anterior orbitotomy by conjunctival incision was performed under general anesthesia. A spherical cystic mass of 1.5 × 1.5 × 1.6 cm, a small eye of 0.7 × 0.7 × 0.6 cm, and a huge dermolipoma were removed completely. Pathologic examination results confirmed the diagnosis of severe microphthalmos, together with orbital dermoid cyst and dermolipoma. This rare case demonstrates that severe microphthalmos with a cyst may be completely covered by conjunctiva and associated with an unusually huge dermolipoma.

  8. Huge plastic bezoar: a rare cause of gastrointestinal obstruction.

    Science.gov (United States)

    Yaka, Mbarek; Ehirchiou, Abdelkader; Alkandry, Tariq Tajdin Sifeddine; Sair, Khalid

    2015-01-01

    Bezoars are rare causes of gastrointestinal obstruction. Basically, they are of four types: trichobezoars, phytobezoars, pharmacobezoars, and lactobezoars. Some rare types of bezoars are also known. In this article a unique case of plastic bezoars is presented. We describe a girl aged 14 years who ingested large amounts of plastic material used for knitting chairs and charpoys. The conglomerate of plastic threads, entrapped food material and other debris, formed a huge mass occupying the whole stomach and extended into small bowel.

  9. A Huge Cystic Retroperitoneal Lymphangioma Presenting with Back Pain

    Science.gov (United States)

    Kubachev, Kubach; Abdullaev, Elbrus; Babyshin, Valentin; Neronov, Dmitriy; Abdullaev, Abakar

    2016-01-01

    Retroperitoneal lymphangioma is a rare location and type of benign abdominal tumors. The clinical presentation of this rare disease is nonspecific, ranging from abdominal distention to sepsis. Here we present a 73-year-old female patient with 3-month history of back pain. USG and CT revealed a huge cystic mass which was surgically excised and appeared to be lymphangioma on histopathology. PMID:27843456

  10. Huge Left Atrium Accompanied by Normally Functioning Prosthetic Valve.

    Science.gov (United States)

    Sabzi, Feridoun

    2015-01-01

    Giant left atria are defined as those measuring larger than 8 cm and are typically found in patients who have rheumatic mitral valve disease with severe regurgitation. Enlargement of the left atrium may create compression of the surrounding structures such as the esophagus, pulmonary veins, respiratory tract, lung, inferior vena cava, recurrent laryngeal nerve, and thoracic vertebrae and lead to dysphagia, respiratory dysfunction, peripheral edema, hoarse voice, or back pain. However, a huge left atrium is usually associated with rheumatic mitral valve disease but is very rare in a normally functioning prosthetic mitral valve, as was the case in our patient. A 46-year-old woman with a past medical history of mitral valve replacement and chronic atrial fibrillation was admitted to our hospital with a chief complaint of cough and shortness of breath, worsened in the last month. Physical examination showed elevated jugular venous pressure, respiratory distress, cardiac cachexia, heart failure, hepatomegaly, and severe edema in the legs. Chest radiography revealed an inconceivably huge cardiac sell-out. Transthoracic echocardiography demonstrated a huge left atrium, associated with thrombosis, and normal function of the prosthetic mitral valve. Cardiac surgery with left atrial exploration for the extraction of the huge thrombosis and De Vega annuloplasty for tricuspid regurgitation were carried out. The postoperative course was eventful due to right ventricular failure and low cardiac output syndrome; and after two days, the patient expired with multiple organ failure. Thorough literature review showed that our case was the largest left atrium (20 × 22 cm) reported thus far in adults with a normal prosthetic mitral valve function.

  11. Huge Left Atrium Accompanied by Normally Function- ing Prosthetic Valve

    Directory of Open Access Journals (Sweden)

    Feridoun Sabzi

    2015-10-01

    Full Text Available Giant left atria are defined as those measuring larger than 8 cm and are typically found in patients who have rheumatic mitral valve disease with severe regurgitation. Enlargement of the left atrium may create compression of the surrounding structures such as the esophagus, pulmonary veins, respiratory tract, lung, inferior vena cava, recurrent laryngeal nerve, and thoracic vertebrae and lead to dysphagia, respiratory dysfunction, peripheral edema, hoarse voice, or back pain. However, a huge left atrium is usually associated with rheumatic mitral valve disease but is very rare in a normally functioning prosthetic mitral valve, as was the case in our patient. A 46-year-old woman with a past medical history of mitral valve replacement and chronic atrial fibrillation was admitted to our hospital with a chief complaint of cough and shortness of breath, worsened in the last month. Physical examination showed elevated jugular venous pressure, respiratory distress, cardiac cachexia, heart failure, hepatomegaly, and severe edema in the legs. Chest radiography revealed an inconceivably huge cardiac sell-out. Transthoracic echocardiography demonstrated a huge left atrium, associated with thrombosis, and normal function of the prosthetic mitral valve. Cardiac surgery with left atrial exploration for the extraction of the huge thrombosis and De Vega annuloplasty for tricuspid regurgitation were carried out. The postoperative course was eventful due to right ventricular failure and low cardiac output syndrome; and after two days, the patient expired with multiple organ failure. Thorough literature review showed that our case was the largest left atrium (20 × 22 cm reported thus far in adults with a normal prosthetic mitral valve function.

  12. Huge Nevus Lipomatosus Cutaneous Superficialis on Back: An Unusual Presentation.

    Science.gov (United States)

    Das, Dipti; Das, Anupam; Bandyopadhyay, Debabrata; Kumar, Dhiraj

    2015-01-01

    Nevus lipomatosus cutaneous superficialis (NLCS) is a benign dermatosis, histologically characterized by the presence of mature ectopic adipocytes in the dermis. We hereby report a case of a 10-year-old boy who presented with multiple huge swellings on the scapular regions and lower back. The lesions were surmounted by small papules, along with peau-d orange appearance at places. Histology showed features consistent with NLCS. The case is being reported for the unusual clinical presentation.

  13. Huge nevus lipomatosus cutaneous superficialis on back: An unusual presentation

    Directory of Open Access Journals (Sweden)

    Dipti Das

    2015-01-01

    Full Text Available Nevus lipomatosus cutaneous superficialis (NLCS is a benign dermatosis, histologically characterized by the presence of mature ectopic adipocytes in the dermis. We hereby report a case of a 10-year-old boy who presented with multiple huge swellings on the scapular regions and lower back. The lesions were surmounted by small papules, along with peau-d orange appearance at places. Histology showed features consistent with NLCS. The case is being reported for the unusual clinical presentation.

  14. Link and Network Layers Design for Ultra-High-Speed Terahertz-Band Communications Networks

    Science.gov (United States)

    2017-01-01

    MATYJAS Work Unit Manager Technical Advisor, Computing & Communications Division Information Directorate This report is published in the...technological advantage. Second, the huge transmission bandwidth associated with the THz-band can satisfy demand for higher data rates in communication ...technological advantage. Second, the huge transmission bandwidth associated with the THz-band can satisfy demand for higher data rates in communication

  15. Huge Intravascular Tumor Extending to the Heart: Leiomyomatosis

    Directory of Open Access Journals (Sweden)

    Suat Doganci

    2015-01-01

    Full Text Available Intravenous leiomyomatosis (IVL is a rare neoplasm characterized by histologically benign-looking smooth muscle cell tumor mass, which is growing within the intrauterine and extrauterine venous system. In this report we aimed to present an unusual case of IVL, which is originating from iliac vein and extended throughout to right cardiac chambers. A 49-year-old female patient, who was treated with warfarin sodium due to right iliac vein thrombosis, was admitted to our department with intermittent dyspnea, palpitation, and dizziness. Physical examination was almost normal except bilateral pretibial edema. On magnetic resonance venography, there was an intravenous mass, which is originated from right internal iliac vein and extended into the inferior vena cava. Transthoracic echocardiography and transesophageal echocardiography revealed a huge mass extending from the inferior vena cava through the right atrium, with obvious venous occlusion. Thoracic, abdominal, and pelvic MR showed an intravascular mass, which is concordant with leiomyomatosis. Surgery was performed through median sternotomy. A huge mass with 25-cm length and 186-gr weight was excised through right atrial oblique incision, on beating heart with cardiopulmonary bypass. Histopathologic assessment was compatible with IVL. Exact strategy for the surgical treatment of IVL is still controversial. We used one-stage approach, with complete resection of a huge IVL extending from right atrium to right iliac vein. In such cases, high recurrence rate is a significant problem; therefore it should be kept in mind.

  16. Multimodality treatment with radiotherapy for huge hepatocellular carcinoma.

    Science.gov (United States)

    Han, Hee Ji; Kim, Mi Sun; Cha, Jihye; Choi, Jin Sub; Han, Kwang Hyub; Seong, Jinsil

    2014-01-01

    For huge hepatocellular carcinoma (HCC), therapeutic decisions have varied from local therapy to systemic therapy, with radiotherapy (RT) playing only a palliative role. In this study, we investigated whether multimodality treatment involving RT could be effective in huge HCC. This study was performed in 116 patients with HCC >10 cm. The number of patients in stage II, III and IV was 12, 54 and 50, respectively. RT was given as a combined modality in most patients. The median dose was 45 Gy, with 1.8 Gy per fraction. The median overall survival (OS) and progression-free survival (PFS) were 14.8 and 6.5 months, respectively. The median infield PFS was not reached. Infield failure, outfield intrahepatic and extrahepatic failure were observed in 8.6, 18.1, and 12.1% of patients, respectively. For OS and PFS, number of tumors, initial alpha-fetoprotein (AFP) level, treatment response, percent AFP decrement, and hepatic resection were significant prognostic factors. Tumor characteristics and treatment response were significantly different between long-term survivors and the other patients. Although huge HCC presents an aggressive clinical course, multimodality approaches involving RT can offer an opportunity for prolonged survival. © 2014 S. Karger AG, Basel.

  17. Huge Intravascular Tumor Extending to the Heart: Leiomyomatosis.

    Science.gov (United States)

    Doganci, Suat; Kaya, Erkan; Kadan, Murat; Karabacak, Kubilay; Erol, Gökhan; Demirkilic, Ufuk

    2015-01-01

    Intravenous leiomyomatosis (IVL) is a rare neoplasm characterized by histologically benign-looking smooth muscle cell tumor mass, which is growing within the intrauterine and extrauterine venous system. In this report we aimed to present an unusual case of IVL, which is originating from iliac vein and extended throughout to right cardiac chambers. A 49-year-old female patient, who was treated with warfarin sodium due to right iliac vein thrombosis, was admitted to our department with intermittent dyspnea, palpitation, and dizziness. Physical examination was almost normal except bilateral pretibial edema. On magnetic resonance venography, there was an intravenous mass, which is originated from right internal iliac vein and extended into the inferior vena cava. Transthoracic echocardiography and transesophageal echocardiography revealed a huge mass extending from the inferior vena cava through the right atrium, with obvious venous occlusion. Thoracic, abdominal, and pelvic MR showed an intravascular mass, which is concordant with leiomyomatosis. Surgery was performed through median sternotomy. A huge mass with 25-cm length and 186-gr weight was excised through right atrial oblique incision, on beating heart with cardiopulmonary bypass. Histopathologic assessment was compatible with IVL. Exact strategy for the surgical treatment of IVL is still controversial. We used one-stage approach, with complete resection of a huge IVL extending from right atrium to right iliac vein. In such cases, high recurrence rate is a significant problem; therefore it should be kept in mind.

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

    Institute of Scientific and Technical Information of China (English)

    Huide; HUANG; Haolun; HUANG; Wanzhen; ZHANG

    2015-01-01

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

  19. 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.

  20. History of Rubber and Its Use

    Science.gov (United States)

    Müller, Ingo; Strehlow, Peter

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

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

    NARCIS (Netherlands)

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

    1999-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Herda Yati Katman

    2016-01-01

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

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

    Science.gov (United States)

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

    2004-01-01

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

  4. Thermal properties of hydrogenated liquid natural rubber

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-25

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

  5. Properties of Nanokaolin and Its Rubber Composites

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  6. Life assessment of rubber articles in fuels

    OpenAIRE

    Selldén, Emmy

    2013-01-01

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

  7. Chemistry of rubber processing and disposal.

    Science.gov (United States)

    Bebb, R L

    1976-01-01

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

  8. Suitability of rubber concrete for railway sleepers

    Directory of Open Access Journals (Sweden)

    Afia S. Hameed

    2016-09-01

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

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

    OpenAIRE

    Chamnarn Thongmark; Jariyaporn Onwong

    2016-01-01

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

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

    OpenAIRE

    Chamnarn Thongmark; Jariyaporn Onwong

    2016-01-01

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

  11. Endoscopic banding ligation can effectively resect hyperplastic Polyps of stomach

    Institute of Scientific and Technical Information of China (English)

    Ching-Chu Lo; Wen-Chi Chen; E-Ming Wang; Kwok-Hung Lai; Ping-I Hsu; Gin-Ho Lo; Hui-Hwa Tseng; Hui-Chun Chen; Ping-Ning Hsu; Chiun-Ku Lin; Hoi-Hung Chan; Wei-Lun Tsai

    2003-01-01

    AIM: Bleeding and perforation are the major and serious complications associated with endoscopic polypectomy. To develop a safe and effective method to resect hyperplastic polyps of the stomach, we employed rubber bands to strangulate hyperplastic polyps and to determine the possibility of inducing avascular necrosis in these lesions.METHODS: Forty-seven patients with 72 hyperplastic polyps were treated with endoscopic banding ligation (EBL). On 14 days after endoscopic ligation, follow-up endoscopies were performed to assess the outcomes of the strangulated polyps.RESULTS: After being strangulated by the rubber bands,all of the polyps immediately became congested (100 %),and then developed cyanotic changes (100 %) approximately 4 minutes later. On follow-up endoscopy 2 weeks later, all the polyps except one had dropped off. The only one residual polyp shrank with a rubber band in its base, and it also dropped off spontaneously during subsequent follow-up.No complications occurred during or following the ligation procedures.CONCLUSION: Gastric polyps develop avascular necrosis following ligation by rubber bands. Employing suction equipment, EBL can easily capture sessile polyps. It is an easy, safe and effective method to eradicate hyperplastic polyps of the stomach.

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

    Science.gov (United States)

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

    2016-04-15

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

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

    Directory of Open Access Journals (Sweden)

    Prüfer Dirk

    2010-02-01

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

  14. Analyzing huge pathology images with open source software.

    Science.gov (United States)

    Deroulers, Christophe; Ameisen, David; Badoual, Mathilde; Gerin, Chloé; Granier, Alexandre; Lartaud, Marc

    2013-06-06

    Digital pathology images are increasingly used both for diagnosis and research, because slide scanners are nowadays broadly available and because the quantitative study of these images yields new insights in systems biology. However, such virtual slides build up a technical challenge since the images occupy often several gigabytes and cannot be fully opened in a computer's memory. Moreover, there is no standard format. Therefore, most common open source tools such as ImageJ fail at treating them, and the others require expensive hardware while still being prohibitively slow. We have developed several cross-platform open source software tools to overcome these limitations. The NDPITools provide a way to transform microscopy images initially in the loosely supported NDPI format into one or several standard TIFF files, and to create mosaics (division of huge images into small ones, with or without overlap) in various TIFF and JPEG formats. They can be driven through ImageJ plugins. The LargeTIFFTools achieve similar functionality for huge TIFF images which do not fit into RAM. We test the performance of these tools on several digital slides and compare them, when applicable, to standard software. A statistical study of the cells in a tissue sample from an oligodendroglioma was performed on an average laptop computer to demonstrate the efficiency of the tools. Our open source software enables dealing with huge images with standard software on average computers. They are cross-platform, independent of proprietary libraries and very modular, allowing them to be used in other open source projects. They have excellent performance in terms of execution speed and RAM requirements. They open promising perspectives both to the clinician who wants to study a single slide and to the research team or data centre who do image analysis of many slides on a computer cluster. The virtual slide(s) for this article can be found here

  15. Visual evoked potentials in rubber factory workers.

    Science.gov (United States)

    Tandon, O P; Kumar, V

    1997-01-01

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

  16. 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.

  17. A NOVEL APPROACH FOR PATTERN ANALYSIS FROM HUGE DATAWAREHOUSE

    Directory of Open Access Journals (Sweden)

    BABITA

    2014-05-01

    Full Text Available Due to the tremendous growth of data and large databases, efficient extraction of required data has become a challenging task. This paper propose a novel approach for knowledge discovery from huge unlabeled temporal databases by employing a combination of HMM and K-means technique. We propose to recursively divide the entire database into clusters having similar characteristics, this process is repeated until we get the cluster’s where no further diversification is possible. Thereafter, the clusters are labeled for knowledge extraction for various purposes.

  18. A young woman with a huge paratubal cyst

    Directory of Open Access Journals (Sweden)

    Ceren Golbasi

    2016-09-01

    Full Text Available Paratubal cysts are asymptomatic embryological remnants. These cysts are usually diagnosed during adolescence and reproductive age. In general, their sizes are small but can be complicated by rupture, torsion, or hemorrhage. Paratubal cysts are often discovered fortuitously on routine ultrasound examination. We report a 19-year-old female patient who presented with irregular menses and abdominal pain. Ultrasound examination revealed a huge cystic mass at the right adnexial area. The diagnosis was confirmed as paratubal cyst during laporotomy and, hence, cystectomy and right salpingectomy were performed. [Cukurova Med J 2016; 41(3.000: 573-576

  19. Modeling huge sound sources in a room acoustical calculation program

    DEFF Research Database (Denmark)

    Christensen, Claus Lynge

    1999-01-01

    A room acoustical model capable of modeling point sources, line sources, and surface sources is presented. Line and surface sources are modeled using a special ray-tracing algorithm detecting the radiation pattern of the surfaces of the room. Point sources are modeled using a hybrid calculation...... method combining this ray-tracing method with image source modeling. With these three source types it is possible to model huge and complex sound sources in industrial environments. Compared to a calculation with only point sources, the use of extended sound sources is shown to improve the agreement...

  20. A huge renal capsular leiomyoma mimicking retroperitoneal sarcoma

    Directory of Open Access Journals (Sweden)

    Lal Anupam

    2009-01-01

    Full Text Available A huge left renal capsular leiomyoma mimicking retroperitoneal sarcoma presented in a patient as an abdominal mass. Computed tomography displayed a large heterogeneous retro-peritoneal mass in the left side of the abdomen with inferior and medial displacement as well as loss of fat plane with the left kidney. Surgical exploration revealed a capsulated mass that was tightly adherent to the left kidney; therefore, total tumor resection with radical left nephrectomy was performed. Histopathology ultimately confirmed the benign nature of the mass. This is the largest leiomyoma reported in literature to the best of our knowledge.

  1. Huge pyometra in a postmenopausal age: a diagnostic dilemma

    Directory of Open Access Journals (Sweden)

    Pramila Yadav

    2015-10-01

    Full Text Available Pyometra in postmenopausal women is an extremely rare disease that hardly responds to the usual treatment of antibiotics therapy. Our case presented as a postmenopausal woman with a huge pyometra. Pyometra drainage was done with great difficulty after a blind biopsy. Endometrial and cervical biopsy followed by endometrial curettage was done. An intrauterine foley's catheter was kept for seven days and Histopathological report was suggestive of squamous cell carcinoma of cervix. [Int J Reprod Contracept Obstet Gynecol 2015; 4(5.000: 1549-1551

  2. Contact allergy to rubber accelerators remains prevalent

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  3. THERMAL CONDUCTIVITY OF RUBBERIZED GYPSUM BOARD

    OpenAIRE

    Taher Abu-Lebdeh; Ellie Fini; Ashraf Fadiel

    2014-01-01

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

  4. Rubber-Modified Epoxies: Transitions and Morphology.

    Science.gov (United States)

    1980-09-01

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

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

    Science.gov (United States)

    Jaworska, E

    1976-01-01

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

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

    Science.gov (United States)

    van Beilen, Jan B; Poirier, Yves

    2007-11-01

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

  7. Microstructure and Properties of Desulfurized Crumb Rubber Modified Bitumen

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

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

  8. Use of waste rubber as concrete additive.

    Science.gov (United States)

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

    2007-02-01

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

    2015-06-01

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

  11. Errors in Seismic Hazard Assessment are Creating Huge Human Losses

    Science.gov (United States)

    Bela, J.

    2015-12-01

    The current practice of representing earthquake hazards to the public based upon their perceived likelihood or probability of occurrence is proven now by the global record of actual earthquakes to be not only erroneous and unreliable, but also too deadly! Earthquake occurrence is sporadic and therefore assumptions of earthquake frequency and return-period are both not only misleading, but also categorically false. More than 700,000 people have now lost their lives (2000-2011), wherein 11 of the World's Deadliest Earthquakes have occurred in locations where probability-based seismic hazard assessments had predicted only low seismic low hazard. Unless seismic hazard assessment and the setting of minimum earthquake design safety standards for buildings and bridges are based on a more realistic deterministic recognition of "what can happen" rather than on what mathematical models suggest is "most likely to happen" such future huge human losses can only be expected to continue! The actual earthquake events that did occur were at or near the maximum potential-size event that either already had occurred in the past; or were geologically known to be possible. Haiti's M7 earthquake, 2010 (with > 222,000 fatalities) meant the dead could not even be buried with dignity. Japan's catastrophic Tohoku earthquake, 2011; a M9 Megathrust earthquake, unleashed a tsunami that not only obliterated coastal communities along the northern Japanese coast, but also claimed > 20,000 lives. This tsunami flooded nuclear reactors at Fukushima, causing 4 explosions and 3 reactors to melt down. But while this history of huge human losses due to erroneous and misleading seismic hazard estimates, despite its wrenching pain, cannot be unlived; if faced with courage and a more realistic deterministic estimate of "what is possible", it need not be lived again. An objective testing of the results of global probability based seismic hazard maps against real occurrences has never been done by the

  12. 21 CFR 801.437 - User labeling for devices that contain natural rubber.

    Science.gov (United States)

    2010-04-01

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

  13. Extractable protein of radiation vulcanized natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

    Soebianto, Y.S. [Center for Research and Development of Isotopes and Radiation Technology, BATAN, Jakarta (Indonesia); Upul, R.M. [Rubber Research Institute of Sri Lanka, Ratmalana (Sri Lanka); Makuuchi, K.; Yoshii, F.; Kume, T. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    A new method to reduce the protein level in the latex products by irradiation is reported. Water soluble protein (WSP) solution (10%) was added into radiation vulcanized NR latex (RVNRL) as much as 3 phr in three different processes: added to RVNRL, added to re-centrifuged RVNRL, and added to RVNRL followed by centrifugation. The protein content was determined by enhanced BCA method, and identified by SDS-PAGE analysis. Addition of WSP followed by centrifugation reduces EP up to the minimum protein detection, and shortens the leaching time to 20-30 min. SDS-PAGE analysis confirms the reduction of soluble protein in the serum phase, and disappearance of protein bands in the rubber extract. Protein-WSP interaction produces water soluble complex, and removed by centrifugation. The molecular weight of WSP dictates the efficiency of protein removal. (author)

  14. Distributed and parallel approach for handle and perform huge datasets

    Science.gov (United States)

    Konopko, Joanna

    2015-12-01

    Big Data refers to the dynamic, large and disparate volumes of data comes from many different sources (tools, machines, sensors, mobile devices) uncorrelated with each others. It requires new, innovative and scalable technology to collect, host and analytically process the vast amount of data. Proper architecture of the system that perform huge data sets is needed. In this paper, the comparison of distributed and parallel system architecture is presented on the example of MapReduce (MR) Hadoop platform and parallel database platform (DBMS). This paper also analyzes the problem of performing and handling valuable information from petabytes of data. The both paradigms: MapReduce and parallel DBMS are described and compared. The hybrid architecture approach is also proposed and could be used to solve the analyzed problem of storing and processing Big Data.

  15. Anaethetic management of a neonate with huge cystic hygroma.

    Directory of Open Access Journals (Sweden)

    Bindi Palkhiwala

    2013-01-01

    Full Text Available We discuss here the case of a 7 day old neonate with huge cystic hygroma on the left side of the neck invading the major vessels of neck, facial nerve, strap muscles and sternocleidomastoid. Anasethtic implications in this case were maintaining airway patency after induction, difficult intubation, risk perioperative dislodgement of tube and judgement of proper time for extubation. Following gaseous induction and adequate mask ventilation, patient was intubated with muscle relaxant. peroperatively to avoid accidental extubation, we choose to manually hold the ET tube after fixing it. At the end of relatively uneventful surgery, we could extubate the patient in OT. patient was shifted to NICU for observation. Post operatively on 3rd day, facial palsy was observed. Ptient was discharged on 21st day.

  16. Huge Intracanal lumbar Disc Herniation: a Review of Four Cases

    Directory of Open Access Journals (Sweden)

    Farzad Omidi-Kashani

    2016-01-01

    Full Text Available Lumbar disc herniation (LDH is the most common cause of sciatica and only in about 10% of the affected patients, surgical intervention is necessary. The side of the patient (the side of most prominent clinical complaints is usually consistent with the side of imaging (the side with most prominent disc herniation on imaging scans. In this case series, we presented our experience in four cases with huge intracanal LDH that a mismatch between the patient’s side and the imaging’s side was present. In these cases, for deciding to do the operation, the physicians need to rely more on clinical findings, but for deciding the side of discectomy, imaging characteristic (imaging side may be a more important criterion.

  17. A parallel solver for huge dense linear systems

    Science.gov (United States)

    Badia, J. M.; Movilla, J. L.; Climente, J. I.; Castillo, M.; Marqués, M.; Mayo, R.; Quintana-Ortí, E. S.; Planelles, J.

    2011-11-01

    HDSS (Huge Dense Linear System Solver) is a Fortran Application Programming Interface (API) to facilitate the parallel solution of very large dense systems to scientists and engineers. The API makes use of parallelism to yield an efficient solution of the systems on a wide range of parallel platforms, from clusters of processors to massively parallel multiprocessors. It exploits out-of-core strategies to leverage the secondary memory in order to solve huge linear systems O(100.000). The API is based on the parallel linear algebra library PLAPACK, and on its Out-Of-Core (OOC) extension POOCLAPACK. Both PLAPACK and POOCLAPACK use the Message Passing Interface (MPI) as the communication layer and BLAS to perform the local matrix operations. The API provides a friendly interface to the users, hiding almost all the technical aspects related to the parallel execution of the code and the use of the secondary memory to solve the systems. In particular, the API can automatically select the best way to store and solve the systems, depending of the dimension of the system, the number of processes and the main memory of the platform. Experimental results on several parallel platforms report high performance, reaching more than 1 TFLOP with 64 cores to solve a system with more than 200 000 equations and more than 10 000 right-hand side vectors. New version program summaryProgram title: Huge Dense System Solver (HDSS) Catalogue identifier: AEHU_v1_1 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEHU_v1_1.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 87 062 No. of bytes in distributed program, including test data, etc.: 1 069 110 Distribution format: tar.gz Programming language: Fortran90, C Computer: Parallel architectures: multiprocessors, computer clusters Operating system

  18. A huge glandular odontogenic cyst occurring at posterior mandible

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Gi Chung; Han, Won Jeong; Kim, Eun Kyung [Dankook University College of Medicine, Seoul (Korea, Republic of)

    2004-12-15

    The glandular odontogenic cyst is a rare lesion described in 1987. It generally occurs at anterior region of mandible in adults over the age of 40 and has a slight tendency to recur. Histopathologically, a cystic cavity lined by a nonkeratinized, stratified squamous, or cuboidal epithelium varying in thickness is found including a superficial layer with glandular or pseudoglandular structures. A 21-year-old male visited Dankook University Dental Hospital with a chief complaint of swelling of the left posterior mandible. Radiographically, a huge multilocular radiolucent lesion involving impacted 3rd molar at the posterior mandible was observed. Buccolingual cortical expansion with partial perforation of buccal cortical bone was also shown. Histopathologically, this lesion was lined by stratified squamous epithelium with glandular structures in areas of plaque-like thickening. The final diagnosis was made as a glandular odontogenic cyst.

  19. Does China's Huge External Surplus Imply an Undervalued Renminbi?

    Institute of Scientific and Technical Information of China (English)

    Anthony J. Makin

    2007-01-01

    A pegged exchange rate regime has been pivotal to China's export-led development strategy. However, its huge trade surpluses and massive build up of international reserves have been matched by large deficits for major trading partners, creating acute policy concerns abroad, especially in the USA. This paper provides a straightforward conceptual framework for interpreting the effect of China's exchange rate policy on its own trade balance and that of trading partners in the context of discrepant economic growth rates. It shows how pegging the exchange rate when output is outstripping expenditure induces China's trade surpluses and counterpart deficits for its trading partners. An important corollary is that given its strictly regulated capital account, China's persistently large surpluses imply a significantly undervalued renminbi, which should gradually become more flexible.

  20. Recycling of Chrome Tanned Leather Dust in Acrylonitrile Butadiene Rubber

    Science.gov (United States)

    El-Sabbagh, Salwa H.; Mohamed, Ola A.

    2010-06-01

    Concerns on environmental waste problem caused by chrome tanned leather wastes in huge amount have caused an increasing interest in developing this wastes in many composite formation. This leather dust was used as filler in acrylonitrile butadiene rubber (NBR) before treatment and after treatment with ammonia solution and sod. formate. Different formulations of NBR/ leather dust (untreated-treated with ammonia solution—treated with sod. formate) composites are prepared. The formed composite exhibit a considerable improvement in some of their properties such as rheometric characteristics especially with composites loaded with treated leather dust. Tensile strength, modulus at 100% elongation, hardness and youngs modulus were improved then by further loading start to be steady or decrease. Cross linking density in toluene were increased by incorporation of leather dust treated or untreated resulting in decreases in equilibrium swelling. Distinct increase in the ageing coefficient of both treated and untreated leather with drop in NBR vulcanizates without leather dust. Addition of leather dust treated or untreated exhibit better thermal stability.

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

    Science.gov (United States)

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

    2006-01-01

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

  2. Band structures in the nematic elastomers phononic crystals

    Science.gov (United States)

    Yang, Shuai; Liu, Ying; Liang, Tianshu

    2017-02-01

    As one kind of new intelligent materials, nematic elastomers (NEs) represent an exciting physical system that combines the local orientational symmetry breaking and the entropic rubber elasticity, producing a number of unique physical phenomena. In this paper, the potential application of NEs in the band tuning is explored. The band structures in two kinds of NE phononic crystals (PCs) are investigated. Through changing NE intrinsic parameters, the influence of the porosity, director rotation and relaxation on the band structures in NE PCs are analyzed. This work is a meaningful try for application of NEs in acoustic field and proposes a new intelligent strategy in band turning.

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

    African Journals Online (AJOL)

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

  4. A crumb rubber modified syntactic foam

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-15

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

  5. Removal Water Turbidity by Crumb Rubber Media

    Directory of Open Access Journals (Sweden)

    Abeer I. Alwared

    2014-06-01

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

  6. Stimuli-responsive cement-reinforced rubber.

    Science.gov (United States)

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

    2014-05-14

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

  7. Generalized thermoelastic wave band gaps in phononic crystals without energy dissipation

    Science.gov (United States)

    Wu, Ying; Yu, Kaiping; Li, Xiao; Zhou, Haotian

    2016-01-01

    We present a theoretical investigation of the thermoelastic wave propagation in the phononic crystals in the context of Green-Nagdhi theory by taking thermoelastic coupling into account. The thermal field is assumed to be steady. Thermoelastic wave band structures of 3D and 2D are derived by using the plane wave expansion method. For the 2D problem, the anti-plane shear mode is not affected by the temperature difference. Thermoelastic wave bands of the in-plane x-y mode are calculated for lead/silicone rubber, aluminium/silicone rubber, and aurum/silicone rubber phononic crystals. The new findings in the numerical results indicate that the thermoelastic wave bands are composed of the pure elastic wave bands and the thermal wave bands, and that the thermal wave bands can serve as the low boundary of the first band gap when the filling ratio is low. In addition, for the lead/silicone rubber phononic crystals the effects of lattice type (square, rectangle, regular triangle, and hexagon) and inclusion shape (circle, oval, and square) on the normalized thermoelastic bandwidth and the upper/lower gap boundaries are analysed and discussed. It is concluded that their effects on the thermoelastic wave band structure are remarkable.

  8. Isolation of Microorganisms Able To Metabolize Purified Natural Rubber

    OpenAIRE

    Heisey, R. M.; Papadatos, S

    1995-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

  10. 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.

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    National Research Council Canada - National Science Library

    Thomas K. Sabu; K.V. Vinod

    2009-01-01

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

  13. Greenhouse Gas Emissions from Rubber Industry in Thailand

    NARCIS (Netherlands)

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

    2010-01-01

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

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

    Science.gov (United States)

    van Beilen, Jan B; Poirier, Yves

    2007-01-01

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

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

    Science.gov (United States)

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

  16. 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

  17. 21 CFR 872.6300 - Rubber dam and accessories.

    Science.gov (United States)

    2010-04-01

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

  18. 27 CFR 21.125 - Rubber hydrocarbon solvent.

    Science.gov (United States)

    2010-04-01

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

  19. 30 CFR 77.606-1 - Rubber gloves; minimum requirements.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Rubber gloves; minimum requirements. 77.606-1... COAL MINES Trailing Cables § 77.606-1 Rubber gloves; minimum requirements. (a) Rubber gloves (lineman's... be used and tested in accordance with the provisions of §§ 77.704-6 through 77.704-8. (b)...

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

    African Journals Online (AJOL)

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

  1. 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.

  2. Development of rubber gloves by radiation vulcanization

    Science.gov (United States)

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

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

  3. The Properties of Sulfur Rubber Concrete (SRC)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

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

  4. Supply of Rubber Wood Log in Malaysia

    Directory of Open Access Journals (Sweden)

    A. W. Noraida

    2014-06-01

    Full Text Available Issue on shortage of raw material for wood processing solved by discovery of rubber wood log as one of the substitutes the natural log. This paper examines the supply of rubber wood log in Malaysia. We employ ARDL Bound Approach Test and time series data from 1980 to 2010 which represented the whole Malaysia are used to achieve the established objectives. The result shown, in the long run harvested area and wages have 1% and 10% significant level respectively. While in the short run, there was only harvested area having an impact with 1% significant level. This result indicates that, the harvested area become the most impact towards supply of rubber wood log either in short run or in the long run. While wages as input cost gave less impact in another word it become unburden to the producers.

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

    DEFF Research Database (Denmark)

    Pettinari, Matteo; Simone, Andrea

    2015-01-01

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

  6. Oxygen exchange in silicone rubber capillaries.

    Science.gov (United States)

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

    1978-06-01

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

  7. The band gap variation of a two dimensional binary locally resonant structure in thermal environment

    Science.gov (United States)

    Li, Zhen; Wang, Xian; Li, Yue-ming

    2017-01-01

    In this study, the numerical investigation of thermal effect on band gap dynamical characteristic for a two-dimensional binary structure composed of aluminum plate periodically filled with nitrile rubber cylinder is presented. Initially, the band gap of the binary structure variation trend with increasing temperature is studied by taking the softening effect of thermal stress into account. A breakthrough is made which found the band gap being narrower and shifting to lower frequency in thermal environment. The complete band gap which in higher frequency is more sensitive to temperature that it disappears with temperature increasing. Then some new transformed models are created by changing the height of nitrile rubber cylinder from 1mm to 7mm. Simulations show that transformed model can produce a wider band gap (either flexure or complete band gap). A proper forbidden gap of elastic wave can be utilized in thermal environment although both flexure and complete band gaps become narrower with temperature. Besides that, there is a zero-frequency flat band appearing in the first flexure band, and it becomes broader with temperature increasing. The band gap width decreases trend in thermal environment, as well as the wider band gap induced by the transformed model with higher nitrile rubber cylinder is useful for the design and application of phononic crystal structures in thermal environment.

  8. The band gap variation of a two dimensional binary locally resonant structure in thermal environment

    Directory of Open Access Journals (Sweden)

    Zhen Li

    2017-01-01

    Full Text Available In this study, the numerical investigation of thermal effect on band gap dynamical characteristic for a two-dimensional binary structure composed of aluminum plate periodically filled with nitrile rubber cylinder is presented. Initially, the band gap of the binary structure variation trend with increasing temperature is studied by taking the softening effect of thermal stress into account. A breakthrough is made which found the band gap being narrower and shifting to lower frequency in thermal environment. The complete band gap which in higher frequency is more sensitive to temperature that it disappears with temperature increasing. Then some new transformed models are created by changing the height of nitrile rubber cylinder from 1mm to 7mm. Simulations show that transformed model can produce a wider band gap (either flexure or complete band gap. A proper forbidden gap of elastic wave can be utilized in thermal environment although both flexure and complete band gaps become narrower with temperature. Besides that, there is a zero-frequency flat band appearing in the first flexure band, and it becomes broader with temperature increasing. The band gap width decreases trend in thermal environment, as well as the wider band gap induced by the transformed model with higher nitrile rubber cylinder is useful for the design and application of phononic crystal structures in thermal environment.

  9. Late Intervention-Related Complication - A Huge Subepicardial Hematoma.

    Science.gov (United States)

    Ko, Po-Yen; Chang, Chih-Ping; Yang, Chen-Chia; Lin, Jen-Jyh

    2013-05-01

    A 75-year-old man had a history of triple vessel coronary artery disease. In August 2009, he had undergone successful percutaneous coronary intervention to the left circumflex coronary artery (LCX) for management of an in-stent restenosis (ISR) lesion. However, in September 2010, he began experiencing recurrent episodes of exertional chest pain. Chest radiography showed the left cardiac border bulging upwards. Transthoracic echocardiography and chest computed tomography revealed a huge oval mass of about 10.4 cm × 7.9 cm × 8.6 cm, which showed calcification and was obliterating the LCX. Subsequent coronary angiography revealed significant instent restenosis, with extravasation of a small amount of contrast material at the stent location, suggesting that the coronary artery had ruptured. We implanted a polytetrafluoroethylene-covered stent to seal the coronary perforation and to release the occlusion. The patient was symptom-free and had an uneventful outcome until the 1-year follow up. Coronary artery perforation; Covered stent; Hematoma.

  10. A huge posteromedial mediastinal cyst complicated with vertebral dislodgment

    Directory of Open Access Journals (Sweden)

    Manoussaridis Jordan T

    2006-08-01

    Full Text Available Abstract Background Mediastinal cysts compromise almost 20% of all mediastinal masses with bronchogenic subtype accounting for 60% of all cystic lesions. Although compression of adjoining soft tissues is usual, spinal complications and neurological symptoms are outmost rare and tend to characterize almost exclusively the neuroenteric cysts. Case presentation A young patient with intermittent, dull pain in his back and free medical history presented in the orthopaedic department of our hospital. There, the initial clinical and radiologic evaluation revealed a mediastinal mass and the patient was referred to the thoracic surgery department for further exploration. The following computed tomography (CT and magnetic resonance imaging (MRI shown a huge mediastinal cyst compressing the T4-T6 vertebral bodies. The neurological symptoms of the patient were attributed to this specific pathology due to the complete agreement between the location of the cyst and the nervous rule area of the compressed thoracic vertebrae. Despite our strongly suggestions for surgery the patient denied any treatment. Conclusion In controversy with the common faith that the spine plays the role of the natural barrier to the further expansion of cystic lesions, our case clearly indicates that, exceptionally, mediastinal cysts may cause severe vertebral complications. Therefore, early excision should be considered especially in young patients or where close follow up is uncertain.

  11. A probabilistic algorithm for interactive huge genome comparison.

    Science.gov (United States)

    Courtois, P R; Moncany, M L

    1995-12-01

    We designed a new probabilistic algorithm, named PAGEC (probabilistic algorithm for genome comparison), which allowed a highly interactive study of long genomic strings. The comparison between two nucleic acid sequences is based on the creation of multiple index tables, which drastically reduces processing time for huge genomes, e.g. 13 min for a 4 Mb/4 Mb comparison. PAGEC lowered the need for memory when compared with other types of algorithm and took into account the low resolution of the final representation (paper or computer screen). Considering that standard printers permit a 300 d.p.i. resolution, the loss of computed information due to the probabilistic conception of the algorithm was not usually noticeable in the present study, mainly due to increased genomic sizes. Refinement was possible through an interactive zooming system, which enabled the visualization of the lexical base sequences of a considered part of both of the studied genomes. Biological examples of computation based on yeast and animal nucleic acid sequences presented in this paper reveal the flexibility of the PAGEC program, which is a valuable tool for genetic studies as it offers a solution to an important problem that will become even more important as time passes.

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

    Directory of Open Access Journals (Sweden)

    Chai Rong Xia

    2016-01-01

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

  13. 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.

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

    OpenAIRE

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

    2016-01-01

    Blends of natural rubber (NR) with styrene butadiene rubber (SBR) with varying ratios have been prepared. Vulcanization of the prepared blends has been induced by irradiation of gamma rays with varying doses up to 250 kGy. Mechanical properties, namely tensile strength, tensile modulus at 100% elongation, elongation at break have been followed up as a function of irradiation dose as well as blend composition. Physical properties, namely gel fraction and swelling number have been followed up u...

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

    OpenAIRE

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

    2006-01-01

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

  16. Natural rubber (NR) biosynthesis: perspectives from polymer chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Barkakaty, Balaka [ORNL

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Wirach Taweepreda

    2013-04-01

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

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

    Science.gov (United States)

    Arguello, J. M.; Santos, A.

    2016-02-01

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

  19. 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.

  20. MRI Verification of a Case of Huge Infantile Rhabdomyoma

    Science.gov (United States)

    Ramadani, Naser; Kreshnike, Kreshnike Dedushi; Muçaj, Sefedin; Kabashi, Serbeze; Hoxhaj, Astrit; Jerliu, Naim; Bejiçi, Ramush

    2016-01-01

    Introduction: Cardiac rhabdomyoma is type of benign myocardial tumor that is the most common fetal cardiac tumor. Cardiac rhabdomyomas are usually detected before birth or during the first year of life. They account for over 60% of all primary cardiac tumors. Case report: A 6 month old child with coughing and obstruction in breathing, was hospitalized in the Pediatric Clinic in UCCK, Pristine. The difficulty of breathing was heard and the pathological noise of the heart was noticed from the pediatrician. In the echo of the heart at the posterior and apico-lateral part of the left ventricle a tumoral mass was presented with the dimensions of 56 × 54 mm that forwarded the contractions of the left ventricle, the mass involved also the left ventricle wall and was not vascularized. The right ventricle was deformed and with the shifting of the SIV on the right the contractility was preserved. Aorta, the left arch and AP were normal with laminar circulation. The pericard was presented free. Radiography of thoracic organs was made; it resulted on cardiomegaly and significant bronchovascular drawing. It was completed with an MRI and it resulted on: Cardiomegaly due to large tumoral mass lesion (60×34 mm) involving lateral wall of left ventricle. It was isointense to the muscle on T1W images, markedly hyperintense on T2W images. There were a few septa or bant like hypointensities within lesion. On postcontrast study it showed avid enhancement. The left ventricle volume was decreased. Mild pericardial effusion was also noted. Surgical intervention was performed and it resulted on the histopathological aspect as a huge infantile rhadbomyoma. Conclusion: In most cases no treatment is required and these lesions regress spontaneously. Patients with left ventricular outflow tract obstruction or refractory arrhythmias respond well to surgical excision. Rhabdomyomas are frequently diagnosed by means of fetal echocardiography during the prenatal period. PMID:27147810

  1. Single-Path Sigma from a Huge Dataset in Taiwan

    Science.gov (United States)

    Sung, Chih-Hsuan; Lee, Chyi-Tyi

    2014-05-01

    Ground-motion variability, which was used in the probabilistic seismic hazard analysis (PSHA) in computing annual exceedence probability, is composed of random variability (aleatory uncertainty) and model uncertainty (epistemic uncertainty). Finding random variability of ground motions has become an important issue in PSHA, and only the random variability can be used in deriving the annual exceedence probability of ground-motion. Epistemic uncertainty will be put in the logic tree to estimate the total uncertainty of ground-motion. In the present study, we used about 18,859 records from 158 shallow earthquakes (Mw > 3.0, focal depth ≤ 35 km, each station has at least 20 records) form the Taiwan Strong-Motion Instrumentation Program (TSMIP) network to analyse the random variability of ground-motion. First, a new ground-motion attenuation model was established by using this huge data set. Second, the residuals from the median attenuation were analysed by direct observation on inter-event variability and site-specific variability. Finally, the single-path variability was found by a moving-window method on either single-earthquake residuals or single-station residuals. A variogram method was also used to find minimum variability for intra-event residuals and inter-event residuals, respectively. Results reveal that 90% of the single-path sigma σSP are ranging from 0.219 to 0.254 (ln unit) and are 58% to 64% smaller than the total sigma (σT =0.601). The single-site sigma (σSS) are also 39%-43% smaller. If we use only random variability (single-path sigma) in PSHA, then the resultant hazard level would be 28% and 25% lower than the traditional one (using total sigma) in 475-year and in 2475-year return period, respectively, in Taipei.

  2. Reinforcement of graphene in natural rubber nanocomposite

    Science.gov (United States)

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

    2016-07-01

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

  3. Valorisation of Proteins from Rubber Tree

    NARCIS (Netherlands)

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

    2016-01-01

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

  4. Rubber Recycling: Chemistry, Processing, and Applications

    NARCIS (Netherlands)

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

    2012-01-01

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

  5. NUTRITIVE VALUE OF RUBBER SEED (Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Md. Emran HOSSAIN

    2016-01-01

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

  6. Numerical modelling of rubber vibration isolators

    NARCIS (Netherlands)

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

    2003-01-01

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

  7. Rubber Impact on 3D Textile Composites

    Science.gov (United States)

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

    2012-06-01

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

  8. Filled liquid silicone rubbers: Possibilities and challenges

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  9. Identification and Waste Reduction on Rubber Industry

    Science.gov (United States)

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

    2017-03-01

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

  10. Cancer mortality and morbidity among rubber workers.

    Science.gov (United States)

    Monson, R R; Fine, L J

    1978-10-01

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

  11. 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.

  12. Changes in rubber plantation in the cross-border area of mainland Southeast Asia through analysis of PALSAR and time series Landsat images

    Science.gov (United States)

    Dong, J.; Xiao, X.; Qin, Y.; Chen, B.; Kou, W.; Zhai, D.; Zhang, G.; Zhang, Y.; Zhou, Y.; Wang, J.

    2015-12-01

    With the increasing demand of natural rubber products in the world market, rubber plantations have dramatically expanded into northern areas of tropical and subtropical zones in Southeast Asia, which have been affecting ecosystem services and human wellbeing. In the cross-border area of five countries (China, Vietnam, Laos, Thailand, and Myanmar), the rubber plantation dynamics varied substantially due to the differences in socioeconomic conditions from local to national scales. However, no spatially explicit information available for this region due to very limited efforts in research and monitoring. Our previous studies have proposed a phenology- and multisensor-based approach to map rubber plantation according to its deciduous feature; however, it is still uncertain that whether the approach can be used for the cross-border area. In this study, we aim to assess the potential of the previous algorithm in the study area by integrating a base forest map from 25-m phase-array L-band synthetic aperture radar (PALSAR) orthorectified mosaic imagery and defoliation information from all the available 30-m Landsat archive imagery. Furthermore, we would compare the changes in the rubber plantation pattern in the five countries from 2007 to 2014. The rubber plantation dynamics in individual countries will be analyzed by considering policies and other factors in different countries. The study would provide valuable information for a broad scientific community (e.g., carbon cycle, biodiversity) and forest management departments.

  13. Pulmonary hypertension with a huge thrombosis in main stem of pulmonary artery

    Institute of Scientific and Technical Information of China (English)

    杨萍; 曾红; 孟繁波; 赵林阳

    2001-01-01

    @@A huge thrombosis in the main stem of the pulmonary artery (PA) with pulmonary hypertension has rarely been reported. We present two cases diagnosed and treated in our hospital. One suffered from polyarteritis with a huge thrombus in PA revealed at autopsy. The second case had congenital heart disease of the patent artery duct; and the huge thrombus was found on echocardiogram and extirpated in surgery.

  14. Huge ascending aortic aneurysm with an intraluminal thrombus in an embolic event-free patient.

    Science.gov (United States)

    Parato, Vito Maurizio; Prifti, Edvin; Pezzuoli, Franco; Labanti, Benedetto; Baboci, Arben

    2015-03-01

    We present a case of an 87-year-old male patient with a huge ascending aortic aneurysm, filled by a huge thrombus most probably due to previous dissection. This finding was detected by two-dimensional transthoracic echocardiography and contrast-enhanced computed tomography (CT) angiography scan. The patient refused surgical treatment and was medically treated. Despite the huge and mobile intraluminal thrombus, the patient remained embolic event-free up to 6 years later, and this makes the case unique.

  15. Band Together!

    Science.gov (United States)

    Olson, Cathy Applefeld

    2011-01-01

    After nearly a decade as band director at St. James High School in St. James, Missouri, Derek Limback knows that the key to building a successful program is putting the program itself above everything else. Limback strives to augment not only his students' musical prowess, but also their leadership skills. Key to his philosophy is instilling a…

  16. Efficacy of hepatic resection for huge (≥ 10 cm) hepatocellular carcinoma: good prognosis associated with the uninodular subtype.

    Science.gov (United States)

    Zhu, Shao-Liang; Chen, Jie; Li, Hang; Li, Le-Qun; Zhong, Jian-Hong

    2015-01-01

    The value of hepatic resection (HR) for huge hepatocellular carcinomas (HCC) (≥ 10 cm in diameter) remains controversial. The aim of this study is to evaluate the efficacy of hepatic resection (HR) for patients with huge HCC. A total of 739 patients with huge HCC (≥ 10 cm in diameter) (huge HCC group, n = 244) or small HCC (huge HCC were identified based on Cox regression analyses. The hospital mortality of these two groups were similar (P = 0.252). The 5-year OS of huge HCC group and small HCC group were 30.3% and 51.9%, respectively (P huge HCC had a significant higher 5-year OS (50.6%) than mutinodular huge HCC (26.9%) (P = 0.016). Multivariate analysis revealed that uninodular huge HCC and absence of PVTT independently predicted better OS for huge HCC patients. HR is a safe and effective approach for the treatment of huge HCC, especially for the uninodular subtype.

  17. Mapping tropical forests and deciduous rubber plantations in Hainan Island, China by integrating PALSAR 25-m and multi-temporal Landsat images

    Science.gov (United States)

    Chen, Bangqian; Li, Xiangping; Xiao, Xiangming; Zhao, Bin; Dong, Jinwei; Kou, Weili; Qin, Yuanwei; Yang, Chuan; Wu, Zhixiang; Sun, Rui; Lan, Guoyu; Xie, Guishui

    2016-08-01

    Updated and accurate maps of tropical forests and industrial plantations, like rubber plantations, are essential for understanding carbon cycle and optimal forest management practices, but existing optical-imagery-based efforts are greatly limited by frequent cloud cover. Here we explored the potential utility of integrating 25-m cloud-free Phased Array type L-band Synthetic Aperture Radar (PALSAR) mosaic product and multi-temporal Landsat images to map forests and rubber plantations in Hainan Island, China. Based on structure information detected by PALSAR and yearly maximum Normalized Difference Vegetation Index (NDVI), we first identified and mapped forests with a producer accuracy (PA) of 96% and user accuracy (UA) of 98%. The resultant forest map showed reasonable spatial and areal agreements with the optical-based forest maps of Fine Resolution Observation and Monitoring Global Land Clover (FROM-GLC) and GlobalLand30. We then extracted rubber plantations from the forest map according to their deciduous features (using minimum Land Surface Water Index, LSWI) and rapid changes in canopies during Rubber Defoliation and Foliation (RDF) period (using standard deviation of LSWI) and dense canopy in growing season (using maximum NDVI). The rubber plantation map yielded a high accuracy when validated by ground truth-based data (PA/UA > 86%) and evaluated with three farm-scale rubber plantation maps (PA/UA >88%). It is estimated that in 2010, Hainan Island had 2.11 × 106 ha of forest and 5.15 × 105 ha of rubber plantations. This study has demonstrated the potential of integrating 25-m PALSAR-based structure information, and Landsat-based spectral and phenology information for mapping tropical forests and rubber plantations.

  18. Efficient visualization of unsteady and huge scalar and vector fields

    Science.gov (United States)

    Vetter, Michael; Olbrich, Stephan

    2016-04-01

    The simulation of climate data tends to produce very large data sets, which hardly can be processed in classical post-processing visualization applications. Within the most traditional post-processing scenarios the visualization pipeline consisting of the processes data generation, visualization mapping and rendering is distributed into two parts over the network or separated via file transfer: the data generation on a supercomputer on the one hand and the other tasks on a special visualization system on the other hand. That way either temporary data sets with huge volume have to be transferred over the network, which leads to bandwidth bottlenecks and volume limitations. As an alternative all simulation and visualization processes are integrated in a monolithic application, where just 2D pixel data is stored, which reduces the user's possibilities for 3D interaction with visualization to frame skipping. Within the Climate Visualization Lab - as part of the Cluster of Excellence "Integrated Climate System Analysis and Prediction" (CliSAP at the University of Hamburg, in cooperation with the German Climate Computing Center (DKRZ) - we plan to integrate a different approach, which has been proven to be successful in former meteorology applications, e.g. PALM (Parallel Large Eddy Simulation Model). Our software framework DSVR is based on the separation of the process chain between the mapping and the rendering processes. We have developed a parallelized visualization library based on MPI and evaluated on various supercomputers. DSVR can be used to integrate the visualization into a parallel simulation model to support in-situ processing, resulting in a sequence of time-based geometric 3D objects which can be interactively rendered in a separate 3D viewer application. To meet the actual requirements (a) to visualize existing data sets, (b) to support more than rectilinear grids, and (c) to integrate in-situ processing in the ICON model, all based on our DSVR framework

  19. Occupational disease in the rubber industry.

    Science.gov (United States)

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

    1976-10-01

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

  20. Synthetic rubbers prepared by lanthanide coordination catalysts

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

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

  1. Synthetic rubbers prepared by lanthanide coordination catalysts

    Institute of Scientific and Technical Information of China (English)

    CHEN WenQi; WANG FoSong

    2009-01-01

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

  2. 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.

  3. 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%.

  4. The influence of natural rubber/Au nanoparticle membranes on the physiology of Leishmania brasiliensis.

    Science.gov (United States)

    Barboza-Filho, Carlos G; Cabrera, Flávio C; Dos Santos, Renivaldo J; De Saja Saez, Jose Antonio; Job, Aldo E

    2012-02-01

    The development of nanotechnology has generated new means of disease diagnosis and treatment. Infectious diseases, including leishmaniasis, malaria, etc., have benefited from the advent of new nanomaterials and/or nanodevices capable of detecting specific antigens and antibodies with high specificity and low cost. In this paper, we present an investigation on a single-celled protozoan Leishmaniasis parasite, a disease considered of standard infectivity, given the high degree of immunological specificity. Natural rubber (NR) membranes incorporating gold nanoparticles (GNPs) were placed in the culture medium and the physiological behavior of Leishmania brasiliensis promastigotes was evaluated. The natural rubber membranes containing GNPs decreased the population growth rate, showing a lower index of living promastigotes (attached to the membrane surface) depending on the amount of nanoparticles deposited in the membrane surface. Such membranes may be used to develop a flexible band-aid for skin lesions from degenerative infection state, inhibiting the population growth of parasites in the lesions. In addition, natural rubber membranes would also stimulate angiogenesis in damaged tissues.

  5. MODIFYING V-14 RUBBER WITH CARBON FIBERS

    Directory of Open Access Journals (Sweden)

    Shadrinov N. V.

    2016-01-01

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

  6. 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 ...

  7. 75 FR 36472 - Goodyear Tire and Rubber Company, Receipt of Petition for Decision of Inconsequential Noncompliance

    Science.gov (United States)

    2010-06-25

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

  8. 78 FR 9775 - Cooper Tire & Rubber Company, Receipt of Petition for Decision of Inconsequential Noncompliance

    Science.gov (United States)

    2013-02-11

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

  9. 76 FR 28502 - Cooper Tire & Rubber Tire Company, Receipt of Petition for Decision of Inconsequential Noncompliance

    Science.gov (United States)

    2011-05-17

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

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

    Directory of Open Access Journals (Sweden)

    Yerbol Tileuberdi

    2012-03-01

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

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

    OpenAIRE

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

    2012-01-01

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

  12. Tensile Strength of PHBV/Natural Rubber Latex Mixtures

    OpenAIRE

    Promkotra Sarunya; Kangsadan Tawiwan

    2015-01-01

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

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

    OpenAIRE

    Coventry, Kathryn; Richardson, Alan; Diaz, Eli

    2015-01-01

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

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

    OpenAIRE

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

    2007-01-01

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

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

    OpenAIRE

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

    2008-01-01

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

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

    DEFF Research Database (Denmark)

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

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

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

    OpenAIRE

    Coventry, Kathryn; Richardson, Alan; Diaz, Eli

    2015-01-01

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

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

    Science.gov (United States)

    Delzell, E; Monson, R R

    1982-07-01

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

  19. 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...

  20. Fibrous dysplasia of the rib presenting as a huge chest wall tumor: report of a case.

    Science.gov (United States)

    Chang, B S; Lee, S C; Harn, H J

    1994-07-01

    Fibrous dysplasia of the rib is not uncommon, but is rarely demonstrated as a huge chest wall mass with severe clinical symptoms. A 59-year-old patient, presenting with a huge, rapidly expanding chest wall tumor compressing the lung, liver and heart accompanied by chest pain and dyspnea, is reported. The tumor was success-fully excised by local radical resection.

  1. Huge van Bordeeus : een ridder van Karel de Grote op avontuur in het Oosten

    NARCIS (Netherlands)

    Lens, Maria Johanna

    2004-01-01

    'Huge van Bordeeus' is de dissertatie van Maria Lens. Hierin doet zij verslag van haar onderzoek naar de Middelnederlandse overlevering van een Franse tekst, 'Huon de Bordeaux', over de ridder Huge van Bordeeus. Deze veertiende-eeuwse ridder, leenman van Karel de Grote, moet de baard en vier tanden

  2. Insulation of nonlinear and random vibrations in the mining industry. [elastodynamic response of rubber insulator

    Science.gov (United States)

    Zeveleanu, C.

    1974-01-01

    The insulation of nonlinear and random vibrations is considered for some ore preparing and sorting implements: rotary crushers, resonance screens, hammer mills, etc. The appearance of subharmonic vibrations is analyzed, and the conditions for their appearance are determined. A method is given for calculating the insulation of these vibrations by means of elastic elements made of rubber. The insulation of the random vibrations produced by Symons crushers is calculated by determining the transmissability and deformation of the insulation system for a narrow band random response.

  3. Electromagnetic properties of carbonyl iron and their microwave absorbing characterization as filler in silicone rubber

    Indian Academy of Sciences (India)

    Yuping Duan; Guofang Li; Lidong Liu; Shunhua Liu

    2010-10-01

    The complex permittivity, permeability and microwave-absorbing properties of rubber composites filled with carbonyl iron are measured at frequencies from 2–18 GHz. The results indicate that the reflection loss peak shifts towards low frequency region with increasing layer thickness or increasing weight concentration. The minimum reflection loss value of –23.06 dB was obtained at 3.3 GHz for the composites with 80% wt. These results show that the composites possess good microwave absorbing ability in both low- and highfrequency bands.

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

    NARCIS (Netherlands)

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

    2014-01-01

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

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

    Science.gov (United States)

    Krzemińska, Sylwia; Rzymski, Władysław M

    2011-01-01

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

  6. Geotechnical Properties of Rubber Tires and Sediments Mixtures

    Directory of Open Access Journals (Sweden)

    H. Sellaf

    2014-04-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

  8. Amphiphilic semi-interpenetrating polymer networks using pulverized rubber

    Science.gov (United States)

    Shahidi, Nima

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  10. Effect of Chipped Rubber Aggregates on Performance of Concrete

    Directory of Open Access Journals (Sweden)

    Sunil N. Shah

    2014-12-01

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

  11. Transarterial chemoembolization for huge hepatocellular carcinoma with diameter over ten centimeters: a large cohort study.

    Science.gov (United States)

    Xue, Tongchun; Le, Fan; Chen, Rongxin; Xie, Xiaoying; Zhang, Lan; Ge, Ningling; Chen, Yi; Wang, Yanhong; Zhang, Boheng; Ye, Shenglong; Ren, Zhenggang

    2015-03-01

    Patients with huge hepatocellular carcinoma >10 cm in diameter represent a special subgroup for treatment. To date, there are few data and little consensus on treatment strategies for huge hepatocellular carcinoma. In this study, we summarized the effects and safety of transarterial chemoembolization for huge hepatocellular carcinoma. A retrospective study was performed based on a large cohort of patients (n = 511) with huge hepatocellular carcinoma who underwent serial transarterial chemoembolization between January 2008 to December 2011 and were followed up until March 2013. We found median survival time was 6.5 months. On multivariate analysis, Child-Pugh class (A versus B) (p huge hepatocellular carcinoma and is recommended as a component of combination therapy. In addition, patients with good liver function and low alpha-fetoprotein levels may acquire greater survival benefits from transarterial chemoembolization.

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

    OpenAIRE

    Wojciech HOMIK

    2011-01-01

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

  13. Male Parent Identification of Triploid Rubber Trees (Hevea brasiliensis and the Mechanism of 2n Gametes Formation

    Directory of Open Access Journals (Sweden)

    Peng-Qiang Yao

    2016-12-01

    Full Text Available Eight triploids were screened among offspring of the rubber tree clone GT1 × different clones by flow cytometry and chromosome counting. Twenty-five simple sequence repeat (SSR markers were screened to identify the origin of 2n gametes, to determine the male parents of these triploids, and to evaluate the mechanism of 2n gamete formation using band configurations and microsatellite DNA allele counting peak ratios (MAC-PR. The results showed that 2n gametes originated from the maternal rubber tree clone GT1, contributing the extra genome copy present in the triploids. It was confirmed that GT1 is able to produce a 2n megagametophyte spontaneously. Many male parents were shown to provide pollen for formation of triploid rubber trees, including clones RRIC 103, Yunyan 277-5, and three other clones. The second division restitution (SDR was likely the main mechanism involved in formation of megagametophytes in GT1, as the rate of maternal heterozygosity restitution (HR of all eight triploids varied from 27.78% to 75.00%, with a mean of 51.46%, and all 25 markers varied from 0% to 100%, with a mean of 51.69%. Elucidation of the origin and formation of 2n gametes will help optimize further sexual hybridization of polyploid rubber trees.

  14. 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.

  15. New application of crystalline cellulose in rubber composites

    Science.gov (United States)

    Bai, Wen

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

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

    Science.gov (United States)

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

    2017-03-01

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

  17. 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.

  18. 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.

  19. Creep Characteristics of Crumb Rubber Modified Asphalt Binder

    Institute of Scientific and Technical Information of China (English)

    WANG Lan; CHANG Chunqing; XING Yongming

    2011-01-01

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

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

    Science.gov (United States)

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

    2008-07-01

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

  1. 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...

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

    Science.gov (United States)

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

  3. 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

  4. Flexible protective diamond-like carbon film on rubber

    NARCIS (Netherlands)

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

    2010-01-01

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

  5. 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.

  6. Top 10 News of China Rubber Industry in 2011

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  8. Viscoelastic properties of short aramid fibres-reinforced rubbers

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    Science.gov (United States)

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

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

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-29

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

  11. 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...

  12. Lifetime of metal rubber isolator with different vibration amplitudes

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  13. Viscoelastic properties of short aramid fibres-reinforced rubbers

    NARCIS (Netherlands)

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

    2013-01-01

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

  14. Cohesion in crumb rubber modified bitumen

    Directory of Open Access Journals (Sweden)

    Páez Dueñas, A.

    2006-12-01

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

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

    Directory of Open Access Journals (Sweden)

    K. Sridharan

    2013-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    SU Rong-hua; PENG Chen-yu

    2011-01-01

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

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

    Science.gov (United States)

    Chen, Bao; Chen, Zheming; Lei, Gang

    2017-01-01

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

  18. 3D silicone rubber interfaces for individually tailored implants.

    Science.gov (United States)

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

    2015-01-01

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

  19. New type of liquid rubber and compositions based on it.

    Science.gov (United States)

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

    2014-11-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  1. Reinforcement of rubber by fractal aggregates

    Science.gov (United States)

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

    1993-03-01

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

  2. On the inflation of a rubber balloon

    Science.gov (United States)

    Vandermarlière, Julien

    2016-12-01

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

  3. 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.

  4. Characterization of Hexsyn, a polyolefin rubber.

    Science.gov (United States)

    McMillin, C R

    1987-07-01

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

  5. Properties of Concrete Containing Scrap-Tire Rubber

    Directory of Open Access Journals (Sweden)

    Mazyad Al-Fadhli

    2017-03-01

    Full Text Available Solid waste management is one of the major environmental concerns all over the world and in Kuwait. Over 5 billion tons of non-hazardous solid waste materials are generated in Kuwait each year. Of these, more than 2 million scrap-tires (approximately 2 million tons are generated each year. In addition to this, about seven million scrap-tires have been stockpiled. Due to the increasingly serious environmental problems presented by waste tires, the feasibility of using elastic and flexible tire–rubber particles as aggregate in concrete is investigated in this study. Tire–rubber particles composed of tire chips, crumb rubber, and a combination of tire chips and crumb rubber, were used to replace mineral aggregates in concrete. These particles were used to replace 10%, 15%, 20%, and 25% of the total mineral aggregate’s volume in concrete. Cylindrical shape concrete specimens 15 cm in diameter and 30 cm in height were fabricated and cured. The fresh rubberized concrete exhibited lower unit weight and acceptable workability compared to plain concrete. The results of a uniaxial compressive strain control test conducted on hardened concrete specimens indicate large reductions in the strength and tangential modulus of elasticity. A significant decrease in the brittle behavior of concrete with increasing rubber content is also demonstrated using nonlinearity indices. The maximum toughness index, indicating the post failure strength of concrete, occurs in concretes with 25% rubber content. Unlike plain concrete, the failure state in rubberized concrete occurs gently and uniformly, and does not cause any separation in the specimen. Crack width and its propagation velocity in rubberized concrete are lower than those of plain concrete. Ultrasonic analysis reveals large reductions in the ultrasonic modulus and high sound absorption for tire–rubber concrete.

  6. Huge hepatocellular carcinoma with multiple intrahepatic metastases: An aggressive multimodal treatment

    Directory of Open Access Journals (Sweden)

    Satoshi Yasuda

    2015-01-01

    Conclusion: Multimodal treatment involving hepatectomy and TACE might be a good treatment strategy for patients with huge HCC with multiple intrahepatic metastases if the tumors are localized in the liver without distant or peritoneal metastasis.

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

    Science.gov (United States)

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

    2015-11-01

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

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  10. Organic acids and protein compounds causing the photoluminescence properties of natural rubber membranes and the quenching phenomena from Au nanoparticle incorporation.

    Science.gov (United States)

    Cabrera, Flávio C; Agostini, Deuber L S; Dos Santos, Renivaldo J; Guimarães, Francisco E G; Guerrero, Ariel R; Aroca, Ricardo F; Job, Aldo E

    2014-12-01

    Natural rubber membranes were fabricated using latex from Hevea brasiliensis trees (clone RRIM 600) by casting, and controlling the time and temperature of thermal treatment. Three temperatures were used: 65, 80 and 120 °C and the corresponding annealing times of 6, 8, 10 and 12 h. The centrifugation of the latex produces the constituent phases: solid rubber (F1), serum or protein components (F2) and bottom fraction (F3). The photoluminescence properties could be correlated with organic acid components of latex. Natural rubber membranes were used as the active substrate (reducing agent) for the incorporation of colloidal Au nanoparticles synthesized by in situ reduction at different times. The intensity of photoluminescence bands assigned to the natural rubber decreases with the increase in amount of nanoparticles present on the membrane surface. It can be assumed that Au nanoparticles may be formed by reduction of the Au cation reacting with functional groups that are directly related to photoluminescence properties. However, the quenching of fluorescence may be attributed to the formation of a large amount of metal nanostructures on the natural rubber surface. Copyright © 2014 John Wiley & Sons, Ltd.

  11. A huge ovarian mucinous cystadenoma causing virilization, preterm labor, and persistent supine hypotensive syndrome during pregnancy.

    Science.gov (United States)

    Kucur, Suna Kabil; Acar, Canan; Temizkan, Osman; Ozagari, Aysim; Gozukara, Ilay; Akyol, Atif

    2016-01-01

    Mucinous cystadenoma (MC) of the ovary is an unilateral, multilocular cystic benign epithelial tumor. Supposed to be hormone responsive, MC reaches huge sizes during pregnancy. Aortocaval compression is common during pregnancy, especially when the pregnant woman is in the supine position. However, the compression recovers with a change in position. The authors report the first case of a huge mucinous cystadenoma of the ovary complicating pregnancy and causing virilization, premature labor, and persistent supine hypotensive syndrome.

  12. Robot-assisted laparoscopic resection of a huge pelvic tumor: A case report.

    Science.gov (United States)

    Jia, Zhuomin; Lyu, Xiangjun; Xu, Yong; Leonardi, Rosario; Zhang, Xu

    2016-07-04

    The traditional open surgery, for the treatment of huge tumor in the narrow space of pelvic cavity and in close proximity to pelvic organs and neurovascular structures, is very difficult and challenging. We report a case of huge neurilemmoma operated using the robot-assisted laparoscopy. We used interventional pre-operation embolization to control blood supply of tumor because MRI showed the tumor had a sufficient blood supply.

  13. Amniotic constriction bands

    Science.gov (United States)

    ... of function of an arm or a leg. Congenital bands affecting the hand often cause the most problems. Alternative Names Pseudo-ainhum; Streeter dysplasia; Amniotic band sequence; Amniotic constriction bands; Constriction band ...

  14. The HUGE formula (hematocrit, urea and gender): association with cardiovascular risk.

    Science.gov (United States)

    Robles, N R; Felix, F J; Fernandez-Berges, D; Perez-Castán, J; Zaro, M J; Lozano, L; Alvarez-Palacios, P; Garcia-Trigo, A; Tejero, V; Morcillo, Y; Hidalgo, A B

    2013-07-01

    To evaluate the relationship between chronic renal failure (CFR) defined through HUGE (hematocrit, urea and gender) formula score and the patient's cardiovascular risk measured through cardiovascular disease antecedents such as ischemic cardiopathy, cerebrovascular disease and peripheral arterial disease. The sample consisted of 2,831 subjects. Mean age was 51.2±14.7 years and 53.5% were female. Serum creatinine, urea, hematocrit and 24h proteinuria were analyzed. HUGE score was calculated from gender, urea and hematocrit. GFR was estimated from uncalibrated serum creatinine using the abbreviated Modification of Diet in Renal Disease equation (MDRD-4). UAE was measured in first morning urine sample. Using HUGE formula 2.2% (n = 61) of subjects had CRF. Of them, 12 (19.7%) had cardiovascular disease history. Among patients without CRF (n = 2770), 194 subjects had history of previous cardiovascular diseases (0.07%; p HUGE definition of CRF was 3.25 (p = 0.001, Mantel-Haenszel test). CFR was associated to higher pulse pressure (PP) and increased urinary albumin excretion. A significant cardiovascular risk was associated to the diagnosis of CRF through HUGE formula. This relation was closer than the obtained using MDRD estimated GFR in spite of a bigger sample. HUGE formula seems to be a useful tool for diagnosing CRF and evaluate the cardiovascular risk of these patients.

  15. Rubber hand illusion affects joint angle perception.

    Directory of Open Access Journals (Sweden)

    Martin V Butz

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

  16. INDUSTRIAL SAFETY IN THE PRODUCTION OF RUBBER

    Directory of Open Access Journals (Sweden)

    S. V. Danilova

    2015-01-01

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

  17. Pyrolysis of Rubber in a Screw Reactor

    Science.gov (United States)

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

    2016-11-01

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

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

    NARCIS (Netherlands)

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

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

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

    NARCIS (Netherlands)

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

    2007-01-01

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

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

    Science.gov (United States)

    2010-07-01

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

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

    Science.gov (United States)

    2010-08-24

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

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

    Science.gov (United States)

    2010-07-01

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

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

    Science.gov (United States)

    2010-07-01

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

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    A. A. El-Wakil

    2011-01-01

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

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

    Science.gov (United States)

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

    2006-12-01

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

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

    Science.gov (United States)

    Helminger, Nicholas P.

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

  8. Mechanical properties and durability of crumb rubber concrete

    Science.gov (United States)

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

    2017-09-01

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

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

    Science.gov (United States)

    Sansatsadeekul, Jitlada; Sakdapipanich, Jitladda; Rojruthai, Porntip

    2011-06-01

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

  10. Microcellular foaming of silicone rubber with supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-15

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

  11. 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

  12. The Abrasion-resistance Investigation of Rubberized Concrete

    Institute of Scientific and Technical Information of China (English)

    KANG Jingfu; ZHANG Bo; LI Guangyu

    2012-01-01

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

  13. Circuit racing, track texture, temperature and rubber friction

    Science.gov (United States)

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

    2016-04-01

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

  14. 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.

  15. Lamb wave band gaps in locally resonant phononic crystal strip waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Yuanwei, E-mail: yaoyw@scut.edu.cn [Department of Physics, Guangdong University of Technology, Guangzhou 510006 (China); Wu, Fugen [Experiment and Educational Center, Guangdong University of Technology, Guangzhou 510006 (China); Zhang, Xin [Department of Physics, Guangdong University of Technology, Guangzhou 510006 (China); Hou, Zhilin [Department of Physics, South China University of Technology, Guangzhou 510640 (China)

    2012-01-09

    Using finite element method, we have made a theoretically study of the band structure of Lamb wave in a locally resonant phononic crystal strip waveguide with periodic soft rubber attached on the two sides of epoxy main plate. The numerical results show that the Lamb wave band gap based on local resonant mechanism can be opened up in the stub strip waveguides, and the width of the local resonant band gap is narrower than that based on the Bragg scattering mechanism. The results also show that the stub shape and width have influence on the frequency and width of the Lamb wave band gap. -- Highlights: ► The local resonant Lamb wave band gap can be opened up in a stub strip waveguides. ► The width of the local resonant band gap is narrower than that Bragg scattering band gap. ► The shape and width of the stub have strongly influence on the local resonant band gap.

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

    OpenAIRE

    Hanbing Liu; Xianqiang Wang; Yubo Jiao; Tao Sha

    2016-01-01

    Recycling waste tire rubber by incorporating it into concrete has become the preferred solution to dispose of waste tires. In this study, the effect of the volume content of crumb rubber and pretreatment methods on the performances of concrete was evaluated. Firstly, the fine aggregate and mixture were partly replaced by crumb rubber to produce crumb rubber concrete. Secondly, the mechanical and durability properties of crumb rubber concrete with different replacement forms and volume content...

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

    Directory of Open Access Journals (Sweden)

    Yu-Fen Chen

    2016-10-01

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

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

    OpenAIRE

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

    2005-01-01

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

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

    OpenAIRE

    Hanbing Liu; Xianqiang Wang; Yubo Jiao; Tao Sha

    2016-01-01

    Recycling waste tire rubber by incorporating it into concrete has become the preferred solution to dispose of waste tires. In this study, the effect of the volume content of crumb rubber and pretreatment methods on the performances of concrete was evaluated. Firstly, the fine aggregate and mixture were partly replaced by crumb rubber to produce crumb rubber concrete. Secondly, the mechanical and durability properties of crumb rubber concrete with different replacement forms and volume content...

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

    Science.gov (United States)

    Widenor, W. M.

    1978-01-01

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

  1. 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.

  2. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  4. 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.

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

    Science.gov (United States)

    1990-10-01

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

  6. Short Fibre and Particulate-reinforced Rubber Composites

    Directory of Open Access Journals (Sweden)

    Kavita Agarwal

    2002-07-01

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

  7. 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.

  8. 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

  9. Thermal and mechanical behavior of rubber systems

    Science.gov (United States)

    Macon, David James

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

  10. The role of pressure in rubber elasticity

    Science.gov (United States)

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

    2004-06-01

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

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

    Directory of Open Access Journals (Sweden)

    H. H. Le

    2017-03-01

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

  12. 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.

  13. Newtonian self-gravitating system in a relativistic huge void universe model

    Science.gov (United States)

    Nishikawa, Ryusuke; Nakao, Ken-ichi; Yoo, Chul-Moon

    2016-12-01

    We consider a test of the Copernican Principle through observations of the large-scale structures, and for this purpose we study the self-gravitating system in a relativistic huge void universe model which does not invoke the Copernican Principle. If we focus on the the weakly self-gravitating and slowly evolving system whose spatial extent is much smaller than the scale of the cosmological horizon in the homogeneous and isotropic background universe model, the cosmological Newtonian approximation is available. Also in the huge void universe model, the same kind of approximation as the cosmological Newtonian approximation is available for the analysis of the perturbations contained in a region whose spatial size is much smaller than the scale of the huge void: the effects of the huge void are taken into account in a perturbative manner by using the Fermi-normal coordinates. By using this approximation, we derive the equations of motion for the weakly self-gravitating perturbations whose elements have relative velocities much smaller than the speed of light, and show the derived equations can be significantly different from those in the homogeneous and isotropic universe model, due to the anisotropic volume expansion in the huge void. We linearize the derived equations of motion and solve them. The solutions show that the behaviors of linear density perturbations are very different from those in the homogeneous and isotropic universe model.

  14. 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...

  15. Allergenic proteins of natural rubber latex.

    Science.gov (United States)

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

    2002-05-01

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

  16. Cellulose nanocrystal reinforced oxidized natural rubber nanocomposites.

    Science.gov (United States)

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

    2016-02-10

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

  17. Silicone-Rubber Microvalves Actuated by Paraffin

    Science.gov (United States)

    Svelha, Danielle; Feldman, Sabrina; Barsic, David

    2004-01-01

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

  18. Polybenzoxazole-filled nitrile butadiene rubber compositions

    Science.gov (United States)

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

    2008-01-01

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

  19. Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites.

    Science.gov (United States)

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

    2015-10-05

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

  20. HYDROPHOBICITY OF CONTAMINATED SILICONE RUBBER SURFACES

    Institute of Scientific and Technical Information of China (English)

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

    2002-01-01

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

  1. Colonic Angiodysplasia with a Huge Submucosal Hematoma in the Sigmoid Colon.

    Science.gov (United States)

    Shimizu, Takayuki; Koike, Daisuke; Nomura, Yukihiro; Ooe, Kenji

    2016-01-01

    Colonic angiodysplasia (AD) with bleeding as a comorbidity in the aging population is being increasingly reported. However, to our knowledge, there is no report on colonic AD accompanied by a huge hematoma. Herein, we report a case of colonic AD with a huge submucosal hematoma. A 75-year-old man with sudden melena was referred to our hospital. Helical computed tomographic angiography (CTA) revealed bleeding from the sigmoid colon. Additionally, colonoscopy showed a huge submucosal hematoma with bleeding in the sigmoid colon. As endoscopic hemostasis was difficult, sigmoidectomy was performed. The pathological diagnosis was colonic AD. The present case indicates that colonic AD should be considered in the differential diagnosis for melena. In addition, the case shows that helical CTA, which is a noninvasive imaging modality, is useful for the diagnosis of colonic AD and is as effective as colonoscopy and angiography for diagnosis.

  2. Robotic resection of huge presacral tumors: case series and comparison with an open resection.

    Science.gov (United States)

    Oh, Jae Keun; Yang, Moon Sool; Yoon, Do Heum; Rha, Koon Ho; Kim, Keung Nyun; Yi, Seong; Ha, Yoon

    2014-06-01

    Clinical case series and analysis. The purpose of the present study is to evaluate the advantages and disadvantages of robotic presacral tumor resection compared with conventional open approach. Conventional open approach for huge presacral tumors in the retroperitoneal space often demands excessive hospitalization and poor cosmesis. Furthermore, narrow surgical field sometimes interrupt delicate procedures. Nine patients with huge (diameter >10 cm) presacral tumors underwent surgery. Five patients among them had robotic procedure and the others had open transperitoneal tumor resection. Operation time, blood loss, hospitalization, and complications were analyzed. Robotic presacral tumor resection showed shorter operation time, less bleeding, and shorter hospitalization. Moreover, there was no complication related to abdominal adhesion. Although robotic resection for presacral tumor still has limitations technically and economically, robotic resection for huge presacral tumors demonstrated advantages over open resection specifically for benign neurogenic tumors.

  3. Giant pulmonary teratoma with huge splenic lymphangiomatosis: a very rare case.

    Science.gov (United States)

    Alsubaie, Hemail M; Alsubaie, Khaled M; Mahfouz, Mohammed Eid

    2017-09-01

    Teratomas are tumors composed of tissues derived from more than one germ cell line. They manifested with a great variety of clinical and radiological features. We report a case of a giant left hemithorax teratoma in a female with huge spleen tumor and review the relevant literature. A 38-year-old female with progressively aggravating dyspnea at rest from a mild trauma. Absent breath sounds on the left side. There was splenomegaly. Computed tomography scan revealed a huge mass (20 × 15 × 18 cm), containing elements of heterogeneous density in the left hemithorax. The spleen tumor was occupying most of the spleen without any other abdominal manifestations. The patient underwent left thoracotomy and laparoscopic splenectomy. Histopathological examination revealed a benign mature teratoma and cystic lymphangiomatosis of the spleen. To the best of our knowledge and after reviewing the available literature this is the first case of huge mature pulmonary teratoma with large cystic spleen lymphangiomatosis.

  4. Huge splenic epidermoid cyst with elevation of serum CA19-9 level.

    Science.gov (United States)

    Matsumoto, Sayo; Mori, Toshifumi; Miyoshi, Jinsei; Imoto, Yoshitaka; Shinomiya, Hirohiko; Wada, Satoshi; Nakao, Toshihiro; Shinohara, Hisamitsu; Yoshida, Sadahiro; Izumi, Keisuke; Okazaki, Jun; Muguruma, Naoki; Takayama, Tetsuji

    2015-01-01

    A 30-year-old female was referred to our hospital for further examination of liver dysfunction. A huge, soft mass was noted in her left upper quadrant on physical examination. Abdominal ultrasonography and computed tomography revealed a huge cystic tumor of 20 cm in the hilus of the spleen. Serum CA19-9 was 491 U/ml, and splenectomy was performed under suspicion of a malignant cystic tumor. The inner surface of the cyst was lined by squamous epithelial cells that were immunohistochemically positive for CA19-9. Serum CA19-9 level was normalized after the surgery. Our case of a very rare, huge epidermoid cyst of the spleen suggests that measurement of the serum CA19-9 level is useful for evaluating therapeutic efficacy of a splenic epidermoid cyst.

  5. Endovascular Treatment of a Huge Hepatic Artery Aneurysm by Coil Embolization Method: A Case Report.

    Science.gov (United States)

    Hemmati, Hossein; Karimian, Mehdi; Moradi, Habibollah; Farid Marandi, Kambiz; Haghdoost, Afrooz

    2015-07-01

    Hepatic artery aneurysms are rare but potentially life threatening. We describe a novel case of a successful endovascular coil embolization of a huge hepatic artery aneurysm. A 67-year-old woman presented with recent abdominal pain that had begun from 2 weeks before referring to our hospital. Sonographic and computerized tomographic (CT) findings revealed a huge hepatic artery aneurysm with 95 mm × 83 mm diameter. The patient underwent an endovascular technique. In aortic angiography, the celiac artery orifice and superior mesenteric artery were so narrow, so sonography was used in order to determine the exact position of the catheter in the celiac artery orifice. The aneurysm was thrombosed using coil embolization. Pulsation of the aneurysm immediately disappeared. Huge hepatic artery aneurysm can be safely treated using coil embolization.

  6. Collaborative treatment of huge intrathoracic meningoceles associated with neurofibromatosis type 1: a case report.

    Science.gov (United States)

    Cho, Deog Gon; Chang, Yong Jin; Cho, Kyu Do; Hong, Jae Taek

    2015-11-10

    An intrathoracic meningocele is a relatively rare disease, and it commonly accompanies neurofibromatosis type 1. Patients tend to have no symptom but if its size is too large and compresses a lung and neighboring organs, it needs shunt drainage or surgical resection. Herein, we present the case of a 52 year-old female patient with huge intrathoracic meningoceles associated with neurofibromatosis type 1, who has complained about chest discomfort and dyspnea at rest. As for a preliminary treatment, a neurosurgeon had performed a cystoperitoneal shunt, but the symptoms continued and the size of mass and the amount of pleural effusion did not change significantly. Therefore, the huge thoracic meningoceles were successfully treated through the thoracotomic approach in combination with lumbar puncture and cerebrospinal fluid drainage. It is reported that double huge intrathoracic meningoceles associated with neurofibromatosis type 1 was successfully treated by a shunting procedure followed by thoracotomic resection with collaboration of a neurosurgeon.

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

    African Journals Online (AJOL)

    2013-03-01

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

  8. Thermo-Mechanical Analyses of Dynamically Loaded Rubber Cylinders

    Science.gov (United States)

    Johnson, Arthur R.; Chen, Tzi-Kang

    2002-01-01

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

  9. Metal Rubber Sensor Appliquis for Rotor Blade Air Project

    Data.gov (United States)

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

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

    Directory of Open Access Journals (Sweden)

    B. P. Uniyal

    1971-01-01

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2017-06-01

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

  14. Ciprofloxacin Release Using Natural Rubber Latex Membranes as Carrier

    National Research Council Canada - National Science Library

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

    2014-01-01

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

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

    NARCIS (Netherlands)

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

    1996-01-01

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

  16. Utilization of surface-treated rubber particles from waste tires

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-01

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

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

    Data.gov (United States)

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

  18. Lightweight Metal RubberTM Sensors and Interconnects Project

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  20. Tribological Aspect of Rubber Based Parts used in Engineering

    Directory of Open Access Journals (Sweden)

    D. Stamenković

    2014-03-01

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

  1. HYBASE : HYperspectral BAnd SElection

    NARCIS (Netherlands)

    Schwering, P.B.W.; Bekman, H.H.P.T.; Seijen, H.H. van

    2009-01-01

    Band selection is essential in the design of multispectral sensor systems. This paper describes the TNO hyperspectral band selection tool HYBASE. It calculates the optimum band positions given the number of bands and the width of the spectral bands. HYBASE is used to assess the minimum number of spe

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

    Science.gov (United States)

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

    2012-07-01

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

  3. Time series analysis of the behavior of brazilian natural rubber

    Directory of Open Access Journals (Sweden)

    Antônio Donizette de Oliveira

    2009-03-01

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

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

    OpenAIRE

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

    2010-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    FengPei

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ozren Ocic

    2010-02-01

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

  7. Studies on Hydrogenation of Liquid Natural Rubber Using Diimide

    Directory of Open Access Journals (Sweden)

    Nur Hanis Adila Azhar

    2015-01-01

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

  8. The toughening mechanism of rubber particles in polypropylene composite

    Science.gov (United States)

    Shi, L.; Xiao, J. M.

    2017-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Florina Carmen Ciornei

    2016-12-01

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

  10. Huge Bilateral Paramesonephric Cysts in a 25 year old Nulliparous woman

    Science.gov (United States)

    Sagili, Haritha; Krishnan, Manikandan; Dasari, Papa

    2013-01-01

    Paraovarian cysts are uncommon adnexal masses which are usually asymptomatic. We describe a case of bilateral huge paramesonephric cysts in a nulliparous woman. A 25-year-old lady presented with abdominal distension for one year duration. Examination and imaging revealed large abdominopelvic cystic masses with no solid areas or septations. Intraoperatively there were huge bilateral paraovarian cysts which were excised. Histopathology revealed low cuboidal to ciliated columnar epithelium with no evidence of ovarian parenchyma suggestive of paramesonephric cyst. Paraovarian cyst should be included in the differential diagnosis of a cystic mass visualised on ultrasound. PMID:24392412

  11. Huge dissected ascending aorta associated with pseudo aneurysm and aortic coarctation feridoun.

    Science.gov (United States)

    Sabzi, Feridoun; Khosravi, Donya

    2015-07-01

    We report a unique case of chronic dissection of the ascending aorta complicated with huge and thrombotic pseudoaneurysm in a patient with coarctation of descending aorta. Preoperative investigations such as transesophageal echocardiography (TEE) confirmed the diagnosis of dissection. Intraoperative findings included a12 cm eccentric bulge of the right lateral side of dilated the ascending aorta filled with the clot and a circular shaped intimal tear communicating with an extended hematoma and dissection of the media layer. The rarity of the report is an association of the chronic dissection with huge pseudoaneurysm and coarctation. The patient underwent staged repair of an aneurysm and coarctation and had an uneventful postoperative recovery period.

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

    Science.gov (United States)

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

    1986-07-01

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

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

    Science.gov (United States)

    Aiello, M A; Leuzzi, F

    2010-01-01

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

  14. Dielectric Properties of Compatibilised EPDM/Silicone rubber Nanocomposites

    Directory of Open Access Journals (Sweden)

    Vijayalekshmi Vijayakumar

    2017-06-01

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

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

    Science.gov (United States)

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

    2007-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

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

    Science.gov (United States)

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

    1999-06-01

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

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

    Science.gov (United States)

    Bolognesi, Claudia; Moretto, Angelo

    2014-10-15

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

  19. DAMAGE OF SILICONE RUBBER INDUCED BY PROTON IRRADIATION

    Institute of Scientific and Technical Information of China (English)

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

    2003-01-01

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

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

    Science.gov (United States)

    Trakuldee, J.; Boonkerd, K.

    2017-07-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

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

    Science.gov (United States)

    Mackerle, Jaroslav

    2004-09-01

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

  3. Green synthesis of colloidal silver nanoparticles using natural rubber latex extracted from Hevea brasiliensis.

    Science.gov (United States)

    Guidelli, Eder José; Ramos, Ana Paula; Zaniquelli, Maria Elisabete D; Baffa, Oswaldo

    2011-11-01

    Colloidal silver nanoparticles were synthesized by an easy green method using thermal treatment of aqueous solutions of silver nitrate and natural rubber latex (NRL) extracted from Hevea brasiliensis. The UV-Vis spectra detected the characteristic surface plasmonic absorption band around 435 nm. Both NRL and AgNO(3) contents in the reaction medium have influence in the Ag nanoparticles formation. Lower AgNO(3) concentration led to decreased particle size. The silver nanoparticles presented diameters ranging from 2 nm to 100 nm and had spherical shape. The selected area electron diffraction (SAED) patterns indicated that the silver nanoparticles have face centered cubic (fcc) crystalline structure. FTIR spectra suggest that reduction of the silver ions are facilitated by their interaction with the amine groups from ammonia, which is used for conservation of the NRL, whereas the stability of the particles results from cis-isoprene binding onto the surface of nanoparticles. Therefore natural rubber latex extracted from H. brasiliensis can be employed in the preparation of stable aqueous dispersions of silver nanoparticles acting as a dispersing and/or capping agent. Moreover, this work provides a new method for the synthesis of silver nanoparticles that is simple, easy to perform, pollutant free and inexpensive.

  4. Image Analysis Determination of the Influence of Surface Structure of Silicone Rubbers on Biofouling

    Directory of Open Access Journals (Sweden)

    Sevil Atarijabarzadeh

    2015-01-01

    Full Text Available This study focuses on how the texture of the silicone rubber material affects the distribution of microbial growth on the surface of materials used for high voltage insulation. The analysis of surface wetting properties showed that the textured surfaces provide higher receding contact angles and therefore lower contact angle hysteresis. The textured surfaces decrease the risk for dry band formation and thus preserve the electrical properties of the material due to a more homogeneous distribution of water on the surface, which, however, promotes the formation of more extensive biofilms. The samples were inoculated with fungal suspension and incubated in a microenvironment chamber simulating authentic conditions in the field. The extent and distribution of microbial growth on the textured and plane surface samples representing the different parts of the insulator housing that is shank and shed were determined by visual inspection and image analysis methods. The results showed that the microbial growth was evenly distributed on the surface of the textured samples but restricted to limited areas on the plane samples. More intensive microbial growth was determined on the textured samples representing sheds. It would therefore be preferable to use the textured surface silicone rubber for the shank of the insulator.

  5. Chromium removal from water by activated carbon developed from waste rubber tires.

    Science.gov (United States)

    Gupta, Vinod Kumar; Ali, Imran; Saleh, Tawfik A; Siddiqui, M N; Agarwal, Shilpi

    2013-03-01

    Because of the continuous production of large amount of waste tires, the disposal of waste tires represents a major environmental issue throughout the world. This paper reports the utilization of waste tires (hard-to-dispose waste) as a precursor in the production of activated carbons (pollution-cleaning adsorbent). In the preparation of activated carbon (AC), waste rubber tire (WRT) was thermally treated and activated. The tire-derived activated carbon was characterized by means of scanning electron microscope, energy-dispersive X-ray spectroscopy, FTIR spectrophotometer, and X-ray diffraction. In the IR spectrum, a number of bands centred at about 3409, 2350, 1710, 1650, and 1300-1000 cm(-1) prove the present of hydroxyl and carboxyl groups on the surface of AC in addition to C═C double bonds. The developed AC was tested and evaluated as potential adsorbent removal of chromium (III). Experimental parameters, such as contact time, initial concentration, adsorbent dosage and pH were optimized. A rapid uptake of chromium ions was observed and the equilibrium is achieved in 1 h. It was also found that the adsorption process is pH dependent. This work adds to the global discussion of the cost-effective utilization of waste rubber tires for waste water treatment.

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

    OpenAIRE

    2012-01-01

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

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

    OpenAIRE

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

    2011-01-01

    Rubber composites are generally produced by the direct incorporation of fillers like carbon black and/or silica into the rubber matrix. The incorporation of different types of nanofillers is the subject of recent research with the aim of preparing composites with special compositions and properties. A successful application of such composites depends mainly on the degree of dispersion of the nano-sized fillers. Recently, a naturally occurring clay mineral, halloysite nanotubes (HNTs), is inve...

  8. A novel application of ADC/K-foaming agent-loaded NBR rubber composites as pressure sensor

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, W E [Physics Department, Faculty of Science, Suez Canal University, Ismailia (Egypt); El-Eraki, M H I [Physics Department, Faculty of Science, Suez Canal University, Ismailia (Egypt); El-Lawindy, A M Y [Physics Department, Faculty of Science, Suez Canal University, Ismailia (Egypt); Hassan, H H [Physics Department, Faculty of Science, Cairo University, Giza (Egypt)

    2006-02-07

    Nitrile butadiene rubber (NBR) structure foam of different apparent densities was obtained by using different concentrations of foaming agent, azodicarbonamide, ADC/K. The true stress-strain characteristics, in case of compression, of foamed samples were measured. It was found that the theoretical values predicted from the simple blending model are in more agreement with the experimental results than those from the square-relationship model. The effect of cyclic loading-unloading and dissipation energy of rubber foams was studied. The results also indicated that foams with low density exhibited a small hysteresis. The electrical properties were found dependent on the foaming agent concentration. This study was assisted by Mott and Gurney equation. The effect of compressive strain on the electrical conductivity of rubber foams was studied. The free current carrier mobility and the equilibrium concentration of charge carrier in the conduction band were produced as functions of compressive strain. The results also indicate that there is a linear variation between pressure and conductivity for all samples, which means that these samples can be used as a pressure sensor. At a certain concentration of foaming agent (5 phr) a change of electrical conductivity by more than three orders is observed at 20% compression strain.

  9. 40 CFR 428.90 - Applicability; description of the pan, dry digestion, and mechanical reclaimed rubber subcategory.

    Science.gov (United States)

    2010-07-01

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

  10. Predicting the glass transition temperature as function of crosslink density and polymer interactions in rubber compounds

    Science.gov (United States)

    D'Escamard, Gabriella; De Rosa, Claudio; Auriemma, Finizia

    2016-05-01

    Crosslink sulfur density in rubber compounds and interactions in polymer blends are two of the composition elements that affect the rubber compound properties and glass transition temperature (Tg), which is a marker of polymer properties related to its applications. Natural rubber (NR), butadiene rubber (BR) and styrene-butadiene rubber (SBR) compounds were investigated using calorimetry (DSC) and dynamic mechanical analysis (DMA). The results indicate that the Di Marzio's and Schneider's Models predict with accuracy the dependence of Tg on crosslink density and composition in miscible blends, respectively, and that the two model may represent the base to study the relevant "in service" properties of real rubber compounds.

  11. Endovascular repair for a huge vertebral artery pseudoaneurysm caused by Behcet's disease

    Institute of Scientific and Technical Information of China (English)

    DONG Zhi-hui; FU Wei-guo; GUO Da-qiao; XU Xin; CHEN Bin; JIANG Jun-hao; YANG Jue; SHI Zheng-yu; WANG Yu-qi

    2006-01-01

    @@ Behcet's disease (BD), a multisystem chronic autoimmune process of unknown etiology,usually leads to arterial impairment. Isolated case reports have described BD-related arterial dissections, pseudoaneurysms or aneurysms.1-4 Recently, we successfully treated a huge vertebral artery pseudoaneurysm (VAPA) in a patient with BD by stent-grafting with preservation of the affected vertebral artery.

  12. Unusual Huge Keratoacanthoma in Sites of in the Previous Split-Thickness Skin Grafted Area

    Directory of Open Access Journals (Sweden)

    Fatih Uygur

    2009-09-01

    Full Text Available Keratoacanthoma (KA is a fairly common keratinizing, squamous neoplasm. The exact etiology of KA is unknown. However, ultraviolet radiation, trauma, chemical carcinogens, viral infections, immunosuppression, genetic factors, radiation and thermal burns have been accused of pathogenesis. In here, we represent an unusual huge KA arising from the previous reconstructed with split-thickness skin graft on the dorsal foot.

  13. Constructing Optimal Coarse-Grained Sites of Huge Biomolecules by Fluctuation Maximization.

    Science.gov (United States)

    Li, Min; Zhang, John Zenghui; Xia, Fei

    2016-04-12

    Coarse-grained (CG) models are valuable tools for the study of functions of large biomolecules on large length and time scales. The definition of CG representations for huge biomolecules is always a formidable challenge. In this work, we propose a new method called fluctuation maximization coarse-graining (FM-CG) to construct the CG sites of biomolecules. The defined residual in FM-CG converges to a maximal value as the number of CG sites increases, allowing an optimal CG model to be rigorously defined on the basis of the maximum. More importantly, we developed a robust algorithm called stepwise local iterative optimization (SLIO) to accelerate the process of coarse-graining large biomolecules. By means of the efficient SLIO algorithm, the computational cost of coarse-graining large biomolecules is reduced to within the time scale of seconds, which is far lower than that of conventional simulated annealing. The coarse-graining of two huge systems, chaperonin GroEL and lengsin, indicates that our new methods can coarse-grain huge biomolecular systems with up to 10,000 residues within the time scale of minutes. The further parametrization of CG sites derived from FM-CG allows us to construct the corresponding CG models for studies of the functions of huge biomolecular systems.

  14. Anatomic trisegmentectomy: An alternative treatment for huge or multiple hepatocellular carcinoma of right liver.

    Science.gov (United States)

    Jia, Changku; Weng, Jie; Qin, Qifan; Chen, Youke; Huang, Xiaolong; Fu, Yu

    2017-04-01

    The patients with huge (≥10cm) or multiple hepatocellular carcinoma (HCC) in the right liver and insufficient size of the remnant left liver can not be performed an operation of right hemihepatectomy because of that liver failure will occur post operation. We designed anatomic trisegmentectomy in right liver to increase the ratio of future liver remnant volume (%FLRV), thus increasing resectability of huge or multiple HCC. Thirteen patients were analyzed by preoperative CT scan for liver and tumor volumetries. If the right hemihepatectomy was done, %FLRV would be at the range of 29.6%-37.5%. However, if trisegmentectomy was done, %FLRV would increase by an average of 14.0%. So patients will not undergo postoperative liver failure due to sufficient %FLRV. Therefore, we designed anatomic trisegmentectomy, with retention of segment 5 or segment 8, to increase %FLRV and increase the resectability for huge or multiple HCC. After trisegmentectomy, the inflow and outflow of remnant liver were maintained well. Severe complications and mortality were not happened post operation. Of the 13 patients, 10 survived up to now. Of the 10 living cases, postoperative lung metastasis was found in 2 and intrahepatic recurrence was found in 1. These 3 patients survive with tumor after comprehensive therapies including oral administration of Sorafenib. Compared to right hemihepatectomy, anatomic trisegmentectomy in right liver guarantees the maximum preservation of %FLRV to increase the resectability of huge or multiple HCC, thus improving the overall resection rate. Copyright © 2017. Published by Elsevier Masson SAS.

  15. Huge hepatocellular carcinoma with multiple intrahepatic metastases: An aggressive multimodal treatment.

    Science.gov (United States)

    Yasuda, Satoshi; Nomi, Takeo; Hokuto, Daisuke; Yamato, Ichiro; Obara, Shinsaku; Yamada, Takatsugu; Kanehiro, Hiromichi; Nakajima, Yoshiyuki

    2015-01-01

    Huge hepatocellular carcinoma (HCC) possesses a potential risk for spontaneous rupture, which leads to a life-threatening complication with a high mortality rate. In addition, a large HCC is frequently accompanied by intrahepatic metastases. We describe, the case of a 74-year-old woman with a huge extrahepatically expanding HCC with multiple intrahepatic metastases who was treated by liver resection with repeated transcatheter arterial chemoembolization (TACE). To prevent tumor rupture or bleeding, we performed right hepatectomy. After the operation, TACE was applied for multiple intrahepatic metastases in the remnant liver. Furthermore, the elevated protein induced vitamin K absence (PIVKA II) level had decreased to limits within the normal range. Three months after the first TACE, computed tomography revealed several recurrences in the liver. TACE was applied for the second and third time and the tumors were well controlled. Although, liver resection is occasionally performed for patients with huge HCC to avoid spontaneous tumor rupture, only surgical approach might not be sufficient for such advanced HCC. To achieve long-term survival, it is necessary to control the residual intrahepatic tumors. We could control multiple intrahepatic metastases with repeated TACEs after hepatectomy. Multimodal treatment involving hepatectomy and TACE might be a good treatment strategy for patients with huge HCC with multiple intrahepatic metastases if the tumors are localized in the liver without distant or peritoneal metastasis. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Hepatic arterial infusion chemotherapy for patients with huge unresectable hepatocellular carcinoma.

    Science.gov (United States)

    Tsai, Wei-Lun; Lai, Kwok-Hung; Liang, Huei-Lung; Hsu, Ping-I; Chan, Hoi-Hung; Chen, Wen-Chi; Yu, Hsien-Chung; Tsay, Feng-Woei; Wang, Huay-Min; Tsai, Hung-Chih; Cheng, Jin-Shiung

    2014-01-01

    The optimal treatment for huge unresectable hepatocellular carcinoma (HCC) remains controversial. The outcome of transcatheter arterial chemoembolization (TACE) for patients huge unresectable HCC is generally poor and the survival benefit of TACE in these patients is unclear. The aim of the study is to compare the effect of hepatic arterial infusion chemotherapy (HAIC) versus symptomatic treatment in patients with huge unresectable HCC. Since 2000 to 2005, patients with huge (size >8 cm) unresectable HCC were enrolled. Fifty-eight patients received HAIC and 44 patients received symptomatic treatment. In the HAIC group, each patient received 2.4+1.4 (range: 1-6) courses of HAIC. Baseline characteristics and survival were compared between the HAIC and symptomatic treatment groups. The HAIC group and the symptomatic treatment group were similar in baseline characteristics and tumor stages. The overall survival rates at one and two years were 29% and 14% in the HAIC group and 7% and 5% in the symptomatic treatment group, respectively. The patients in the HAIC group had significantly better overall survival than the symptomatic treatment group (Phuge unresectable HCC.

  17. A Computational Method for Enabling Teaching-Learning Process in Huge Online Courses and Communities

    Science.gov (United States)

    Mora, Higinio; Ferrández, Antonio; Gil, David; Peral, Jesús

    2017-01-01

    Massive Open Online Courses and e-learning represent the future of the teaching-learning processes through the development of Information and Communication Technologies. They are the response to the new education needs of society. However, this future also presents many challenges such as the processing of online forums when a huge number of…

  18. A Huge Subcutaneous Hematoma in an Adult with Kasabach-Merritt Syndrome.

    Science.gov (United States)

    Wu, Kuan-Lin; Liao, Chiung-Ying; Chang, Chen-Kuang; Ho, Shang-Yun; Tyan, Yeu-Sheng; Huang, Yuan-Chun

    2017-06-19

    BACKGROUND Kasabach-Merritt syndrome is a potentially fatal disease that consists of hemangioma(s) with thrombocytopenia, microangiopathic hemolytic anemia, and coagulopathy. Extensive hemangiomatosis is rare. We present the radiological features and treatment strategy of a young adult suffering from Kasabach-Merritt syndrome with widespread hemangiomas and an infected huge hematoma in the right thigh. CASE REPORT A 33-year-old Taiwanese male presented with a painful 20-cm mass over his right thigh and gross hematuria for 2 days. Hemangiomatosis was bioptically proven in infancy and the patient was under regular follow-up. Physical examination revealed normal heart rate, respiratory rate, and body temperature. Multiple palpable lumps with brown and purple areas of skin over the neck, trunk, and right thigh were noted. Laboratory examinations revealed thrombocytopenia anemia and elevated fibrin degradation products. There were no signs of sepsis. Blood transfusion and steroid therapy were executed. Computed tomography showed a huge complicated subcutaneous hematoma in the right thigh. Drainage of the huge hematoma was performed and antibiotics were prescribed. After the local infection in the right thigh and the bleeding tendency were controlled, the patient was discharged in a stable condition two weeks later. CONCLUSIONS A huge infected hematoma and widespread hemangiomas are extremely rare complications of Kasabach-Merritt syndrome. There are no known treatment guidelines currently available. Our patient was successfully treated with steroids, drainage, and antibiotics.

  19. A Huge Ovarian Cyst in a Middle-Aged Iranian Female

    Directory of Open Access Journals (Sweden)

    Mohammad Kazem Moslemi

    2010-05-01

    Full Text Available A 38-year-old Iranian woman was found to have a huge ovarian cystic mass. Her presenting symptom was vague abdominal pain and severe abdominal distention. She underwent laparotomy and after surgical removal, the mass was found to be mucinous cystadenoma on histology.

  20. Huge right atrial myxoma causing fixed tricuspid stenosis with constitutional symptoms.

    Science.gov (United States)

    Kuralay, Erkan; Cingöz, Faruk; Günay, Celalettin; Demirkiliç, Ufuk; Tatar, Harun

    2003-01-01

    Nonspecific constitutional symptoms are reported mostly in patients with left-atrial myxomas, which occur five times as often as its right-atrial counterpart. We present huge right-atrial myxoma, which obstructs tricuspid orifice with nonspecific constitutional symptoms without any pulmonary embolism attack.

  1. Preserving stability of huge agriculture machines with internal mobilities: Application to a grape harvester

    OpenAIRE

    Dieumet, D.; Thuilot, B.; Lenain, R.; Berducat, M.

    2012-01-01

    International audience; This paper proposes an algorithm for estimating on-line the rollover risk of huge machine moving on natural ground. The approach is based on the reconstruction of lateral load transfer thanks to an observer, able to take into account terrain specificities (grip conditions and geometry). Capabilities are tested through experiments on a grape harvester.

  2. Dynamically vulcanized biobased polylactide/natural rubber blend material with continuous cross-linked rubber phase.

    Science.gov (United States)

    Chen, Yukun; Yuan, Daosheng; Xu, Chuanhui

    2014-03-26

    We prepared a biobased material, dynamically vulcanized polylactide (PLA)/natural rubber (NR) blend in which the cross-linked NR phase owned a continuous network-like dispersion. This finding breaks the traditional concept of a sea-island morphology formed after dynamic vulcanization of the blends. The scan electron microscopy and dissolution/swell experiments provided the direct proof of the continuous cross-linked NR phase. This new biobased PLA/NR blend material with the novel structure is reported for the first time in the field of dynamic vulcanization and shows promise for development for various functional applications.

  3. Burlap bands as a sampling technique for green anoles (Anolis carolinensis) and other reptiles commonly found in tree boles

    Science.gov (United States)

    Scott Horn; James L. Hanula

    2006-01-01

    A variety of methods have been used to study lizard populations including rubber bands, active searching and noosing (Campbell and Christman 1982; Karns 1986; Simmons 1987), pitfall traps (Fair and Henke 1997; Moseley 2004; Sutton et al. 1999), glue boards (Bauer and Sadlier 1992; Downes and Borges 1998; Durtsche 1996; Moseley 2004;...

  4. Burlap bands as a sampling technique for green anoles (Anolis carolinensis) and other reptiles commonly found on tree boles

    Science.gov (United States)

    Scott Horn; James L. Hanula

    2006-01-01

    A variety of methods have been used to study lizard populations including rubber bands, active searching and noosing (Campbell and Christman 1982; Karns 1986; Simmons 1987), pitfall traps (Fair and Henke 1997; Moseley 2004; Sutton et al. 1999), glue boards (Bauer and Sadlier 1992; Downes and Borges 1998; Durtsche 1996; Moseley 2004; Whiting 1998), extraction by hook (...

  5. Biliary obstruction due to a huge simple hepatic cyst treated with laparoscopic resection.

    Science.gov (United States)

    Kaneya, Yohei; Yoshida, Hiroshi; Matsutani, Takeshi; Hirakata, Atsushi; Matsushita, Akira; Suzuki, Seiji; Yokoyama, Tadashi; Maruyama, Hiroshi; Sasajima, Koji; Uchida, Eiji

    2011-01-01

    Most hepatic cysts are asymptomatic, but complications occasionally occur. We describe a patient with biliary obstruction due to a huge simple hepatic cyst treated with laparoscopic resection. A 60-year-old Japanese woman was admitted to our hospital because of a nontender mass in the right upper quadrant of the abdomen. Laboratory tests revealed the following: serum total bilirubin, 0.6 mg/dL; serum aspartate aminotransferase, 100 IU/L; serum alanine aminotransferase, 78 IU/L; serum alkaline phosphatase, 521 IU/L; and serum gamma glutamic transpeptidase, 298 IU/L. Abdominal computed tomography, ultrasonography, and magnetic resonance cholangiopancreatography revealed a huge hepatic cyst, 13 cm in diameter, at the hepatic hilum, accompanied by dilatation of the intrahepatic bile duct and obstruction of the common bile duct. We diagnosed biliary obstruction due to a huge hepatic cyst at the hepatic hilum, and laparoscopic surgery was performed. A huge hepatic cyst was seen at the hepatic hilum. After needle puncture of the huge cyst, the anterior wall of the cyst was unroofed, and cholecystectomy was done. Intraoperative cholangiography through a cystic duct revealed stenosis of the duct. Subsequent decapsulation of the cyst was performed in front of the common bile duct. After this procedure, cholangiography revealed that the stenosis of the common bile duct had resolved. Histopathological examination of the surgical specimen confirmed the hepatic cyst was benign. The postoperative course was uneventful, and the results of liver function tests normalized. The patient was discharged 7 days after operation. Computed tomography 3 months after operation revealed disappearance of the hepatic cyst and no dilatation of the intrahepatic bile duct.

  6. The unique processing of rubber-insulated wires by radiation

    Science.gov (United States)

    Ishitani, Hayao; Saito, Eisuke; Sasaki, Yasushi

    Ethylene-propylene rubbers are able to be crosslinked (vulcanized) by high energy radiation. The radiation-induced crosslinking of ethylene-propylene copolymer or ethylene-propylene-diene terpolymer depends upon the ethylene/propylene ratio, the molecular weight of the polymer, the unsaturating degree of terpolymer and kinds of tercomponents. The mechanical properties of the crosslinked rubber were affected mainly by the E/P ratio and the molecular weight, and improved by blending of low density polyethylene or ethylene-vinylacetate copolymer. Aging of the rubber, due to kinds and contents of tercomponents, was mostly determined by addition of antioxidants to the compound. We developed EP rubber compounds for wire insulation crosslinked by electron beam radiation and applied to the insulation cores of the ship's cables, in the place of the wire vulcanized conventionally by the pressurized steam in the continuous vulcanizer. The rubber compounds are consisted of ethylene-propylene-diene terpolymer with high ethylene contents, ethylene-vinylacetate copolymer and antioxidants. The high-ethylene polymers are supplied in the shape of pellets, and antioxidants were added to the compounds by means of dry blending of concentrates in which antioxidants are mixed into pellets of ethylene copolymer. The EP rubbers were covered on the copper wire by the extruder, used to plastic material, and irradiated with the electron beam from an accelerator. These insulated cores manufactured on radiation processing had the excellent properties, particularly aging and electrical properties. Further, they are more simply colored. Therefore, they will be considered to be used to other applications. This method of manufacturing of the rubber-insulated wires made it possible to reduce both the material costs by simple compounding and the operating costs by radiation-induced crosslinking, to compare with the conventional compounding and vulcanizing process, in which the materials are

  7. Interaction of Chloroprene and Nitrile- Butadiene Rubber with Lubricating Greases and Base Oils

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The present communication addresses compatibility of two synthetic rubber types, chloroprene and nitrilebutadiene ones, with a number of base oils of petroleum origin and lubricating greases produced thereof. Four base oils,including three naphthenic products with varying degrees of refining and one paraffinic product,were compared with each other in terms of their effect on the rubbers. Degenerative changes occurring in the rubbers on contact with the oils and greases were studied using accelerated ageing tests. Alterations in rubber parameters, such as hardness, weight and glass transition temperature, caused by interaction with oil were monitored. The main physicochemical mechanisms standing behind the changes observed in the rubber properties were found to be (i) migration of plasticizer from rubber into the oil phase, (ii) absorption of oil by rubber,and (iii) oxidation of rubber. An increase in glass transition temperature (Tg) of rubber aged in a base oil or grease was considered as an indirect indication that the plasticizer had migrated out of rubber;the plasticizer accumulation in the oil phase being directly confirmed by gas chromatography. In order to suppress the plasticizer migration, oil additivation with dioctyl adipate (DOA), a common plasticizer used in rubber formulations, was attempted. However, the BOA-additivated oils, while reducing plasticizer migration, were found to cause more swelling than the original oils in the case of chloroprene rubber. As an alternative, replacement of BOA by an alkylated aryl phosphate in nitrile- butadiene rubber formulations was considered, but it did not solve the problem either.The results of this study suggest conclusively that the type of rubber, the plasticizer, and the base oil are all the crucial parameters that should be considered when matching rubber with oil in real- life applications. Interaction of rubber with base oils and with greases produced thereof is largely controlled by (i) solvency of the

  8. Negative pressures during swing phase in below-knee prostheses with rubber sleeve suspension.

    Science.gov (United States)

    Chino, N; Pearson, J R; Cockrell, J L; Mikishko, H A; Koepke, G H

    1975-01-01

    Negative pressures in the small space between the distal stump and the below-knee prosthetic socket were measured during swing phase for a series of nine subjects. A molded rubber sleeve connecting the prosthesis and the thigh was found to enhance this effect so that suction suspension occurred during the entire swing phase. Deterioration of the suction occurred when the sleeve was intentionally pierced, and when other suspensions such as a suprapatellar cuff or thigh band were tested. The findings indicate that the total-contact socket, gel liner and elastic sleeve combine to create suction in the below-knee socket which improves overall comfort and function for the patient in using the prosthesis.

  9. Random parking, Euclidean functionals, and rubber elasticity

    CERN Document Server

    Gloria, Antoine

    2012-01-01

    We study subadditive functions of the random parking model previously analyzed by the second author. In particular, we consider local functions $S$ of subsets of $\\mathbb{R}^d$ and of point sets that are (almost) subadditive in their first variable. Denoting by $\\xi$ the random parking measure in $\\mathbb{R}^d$, and by $\\xi^R$ the random parking measure in the cube $Q_R=(-R,R)^d$, we show, under some natural assumptions on $S$, that there exists a constant $\\bar{S}\\in \\mathbb{R}$ such that % $$ \\lim_{R\\to +\\infty} \\frac{S(Q_R,\\xi)}{|Q_R|}\\,=\\,\\lim_{R\\to +\\infty}\\frac{S(Q_R,\\xi^R)}{|Q_R|}\\,=\\,\\bar{S} $$ % almost surely. If $\\zeta \\mapsto S(Q_R,\\zeta)$ is the counting measure of $\\zeta$ in $Q_R$, then we retrieve the result by the second author on the existence of the jamming limit. The present work generalizes this result to a wide class of (almost) subadditive functions. In particular, classical Euclidean optimization problems as well as the discrete model for rubber previously studied by Alicandro, Cicalese,...

  10. Oil Gels Based on Styrene Butadiene Rubber

    Institute of Scientific and Technical Information of China (English)

    ZHOU Mei-hua (周美华); XU Jing-bo(徐静波); Won-jei CHO

    2004-01-01

    Four oil absorbents based on styrene butadiene (SBR),i. e., pure SBR (PS), 4- tert-butylstyrene-SBR (PBS),EPDM-SBR network (PES) and 4-tert-butylstyrene-EPDMSBR ( PBES ), were produced from crosslinking polymerization of uncured styrene butadiene rubber (SBR),4- tert-butylstyrene ( tBS ) and ethylene-propylene-diene terpolymer (EPDM). The reaction took place in toluene using benzoyl peroxide (BPO) as an initiator. Uncured SBR was used as both a pre-polymer and a crosslink agent in this work, and the crosslinked polymer was identified by IR spectroscopy. The oil absorbency of the crosslinked polymer was evaluated with the method ASTM (F726 - 81). The order of maximum oil absorbency was PBES > PBS >PES > PS. The maximum values of oil absorbency of PBES and PBS were 74.0g/g and 69.5g/g, respectively. Gel fractions and swelling kinetic constants, however, had the opposite sequences. The swelling kinetic constant of PS evaluated by an experimental equation was 49. 97 ×10-2h-1.

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

    Science.gov (United States)

    Mansilla, M. A.; Marzocca, A. J.

    2012-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-08-15

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

  13. DEPENDENCE OF DAMPING CHARACTERISTICS OF A BEAM WITH DAMPING RUBBER MAGNETIC POWDER ON RUBBER PROPERTY

    Institute of Scientific and Technical Information of China (English)

    Ming Li; Zeng He; Huiming Zheng; Ning Zhang

    2008-01-01

    A cantilever beam with Damping Material Applying Rubber Magnetic Powder (DRM)has been investigated.Two methods are selected to hold DRM to a vibrating steel beam,one is to attach DRM by the magnetic attractive force (called DRM beam) and the other by adhesive bonding (called AB-DRM beam).Different from the damping property of AB-DRM beam caused by shear deformation of damping material,the damping property of DRM beam is characterized by the sliding frictional loss together with the internal loss of damping material.The authors established a formulation to predict the damping characteristics of DRM beam,which was validated experimentally.It is found that rubber material loss factor/β has a decisive influence on damping improvement of DRM beam versus AB-DRM beam.If/β is smaller than the critical value around 0.8255,a valid range of vibratory amplitude always exists in which DRM beam can achieve better damping than AB-DRM beam;conversely,if/β is bigger than the critical value,the valid range does not exist when slide occurs.Such results are used to determine the merits and limitations of DRM and develop design guidelines.

  14. 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

  15. VARIATION OF PHYSICO-CHEMICAL PROPERTIES OF RADIATION CROSSLINKED RUBBER WITH STORAGE TIME

    Institute of Scientific and Technical Information of China (English)

    N.C. Dafader; M.E. Haque; F. Akhtar

    2005-01-01

    The effect of storage on physico-chemical properties of non-irradiated natural rubber and radiation vulcanized natural rubber (RVNR) were evaluated. The rubber films were stored under two different conditions, namely in open air and sealed polyethylene bags. The antioxidant, tris(nonylated phenyl) phosphite (TNPP) was used for preventing degradation of RVNR films. Gel content, cross-link density, tensile strength at break and 500% elongation of rubber films were measured.The results show that the retention (%) of tensile properties of rubber films with TNPP is higher than that of rubber films without antioxidants. The rubber films stored in polyethylene bags also show better retention of tensile properties than those of rubber films stored in open air.

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

    Institute of Scientific and Technical Information of China (English)

    程廷海; 高焓; 包钢

    2011-01-01

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

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

    National Research Council Canada - National Science Library

    Zhou, Haiping; Holikatti, Sri; Vacura, Peter

    2014-01-01

    ...) 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Hoeprich, Paul D.; Whalen, Maureen

    2016-04-05

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

  19. Microclimate, development and productivity of robusta coffee shaded by rubber trees and at full sun

    National Research Council Canada - National Science Library

    André Vasconcellos Araújo; Fábio Luiz Partelli; Gleison Oliosi; José Ricardo Macedo Pezzopane

    2016-01-01

      There are few studies about the shading of Robusta coffee with rubber trees. The aim of this study was evaluate the microclimate, development and yield of Coffea canephora grown at full sun and shaded by rubber trees...

  20. Patch testing with rubber series in Europe : a critical review and recommendation

    NARCIS (Netherlands)

    Warburton, Katharine L; Uter, Wolfgang; Geier, Johannes; Spiewak, Radoslaw; Mahler, Vera; Crépy, Marie-Noëlle; Schuttelaar, Marie-Louise; Bauer, Andrea; Wilkinson, Mark

    2016-01-01

    BACKGROUND: Rubber additives constitute an important group of contact allergens, particularly in certain occupations. OBJECTIVES: To collect information regarding the current practice of using a 'rubber series' in Europe, and discuss this against the background of evidence concerning the prevalence

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

    Energy Technology Data Exchange (ETDEWEB)

    Kanazawa, Kenji; Matsuda, Akihiro; Hirata, Kazuta [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Abiko Research Lab.

    1997-08-01

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

  2. Taxonomic revision and phylogenetic analyses of rubber powdery mildew fungi.

    Science.gov (United States)

    Liyanage, K K; Khan, Sehroon; Brooks, Siraprapa; Mortimer, Peter E; Karunarathna, Samantha C; Xu, Jianchu; Hyde, Kevin D

    2017-02-09

    Powdery mildew is a fungal disease that infects a wide range of plants, including rubber trees, which results in a reduction of latex yields of up to 45%. The causal agent of powdery mildew of rubber was first described as Oidium heveae, but later morpho-molecular research suggested that in the past, O. heveae has been confused with Erysiphe quercicola. However, it is still under debate whether the causal agent should be classified as a species of the genus Erysiphe emend. or Golovinomyces and Podosphaera, respectively. Therefore, the aim of this study was to undertake the morpho-molecular characterization of powdery mildew species associated with rubber trees, thus resolving these taxonomic issues. Morphological observation under light and scanning electron microscopes (SEM) clearly identified two morphotypes of the rubber powdery mildew. With the support of morphological and phylogenetic data, one of the two morphotypes was identified as the asexual morph of E. quercicola, while the second morphotype is still insufficiently known and according to the morphological results obtained we assume that it might belong to the genus Golovinomyces. More collections and additional molecular data are required for final conclusions regarding the exact taxonomic position of the second morphotype of rubber powdery mildew and its relation to the name O. heveae. The haplotype analysis identified eight haplotype groups of E. quercicola indicating the high genetic diversity of the species.

  3. 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.

  4. Relaxation phenomena in rubber/layered silicate nanocomposites

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available Broadband Dielectric Spectroscopy (BDS is employed in order to investigate relaxation phenomena occurring in natural rubber (NR, polyurethane rubber (PUR and PUR/NR blend based nanocomposites, reinforced by 10 parts per hundred (phr Layered Silicates (LS. Nanocomposites and matrices were examined under identical conditions in a wide frequency (10–1 to 106 Hz and temperature (–100 to 50°C range. Experimental data are analyzed in terms of electric modulus formalism. The recorded relaxation phenomena include contributions from both the polymer matrices and the nanofiller. Natural rubber is a non-polar material and its performance is only slightly affected by the presence of layered silicates. Polyurethane rubber exhibits four distinct relaxation processes attributed, with ascending relaxation rate, to Interfacial Polarization (IP, glass/rubber transition (α-mode, local motions of polar side groups and small segments of the polymer chain (β, γ-mode. The same processes have been detected in all systems containing PUR. IP is present in all nanocomposites being the slowest recorded process. Finally, pronounced interfacial relaxation phenomena, occurring in the PUR+10 phr LS spectra, are attributed to nanoscale effects of intercalation and exfoliation.

  5. Mechanochromism of a luminescent natural rubber under tensile deformation

    Science.gov (United States)

    Ha, Jimin; Park, Minwook; Jeong, Kwang-Un; Nah, Changwoon

    2016-09-01

    Various examples are reported of chromogenic materials composed of a functional dye covalently linked to the polymer chains or physically dispersed in the continuous macromolecular matrix, the latter appears to be a more sustainable route for the industrial scale-up of these materials. In this study, a mechanochromic elastomer was prepared by physically dispersing dye materials into a rubber matrix by solution mixing technique. The employed rubber is natural rubber (NR). The NR was chosen because of its ability of strain-induced crystallization. Perylene diimide I is selected after considering its aggregachromic nature and affinity with rubber matrix. The optimum composition of dye in rubber composites was determined based on the mechanochromic performance characterized with ultraviolet/visible (UV/Vis) spectrometer, x-ray diffraction (XRD) and spectrofluorometer (FL). The UV/Vis spectrometer and FL monitor the optical responses, such as absorbance and emission property, under tensile deformation due to the breakage of dye aggregates. Spectroscopic analysis with polarization monitors the breakage of dye aggregates and anisotropic property of the sample. The XRD monitors the change in size of dye aggregates. With polarization filtering, the breakage of dye aggregates are clearly observed and anisotropic property of the sample is also confirmed. The XRD results indicate that dye aggregates were broken during stretching because the shear force is applied to dye aggregates.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. China Rubber Chemicals Production and Market Situation Analysis

    Institute of Scientific and Technical Information of China (English)

    Liang Cheng

    2011-01-01

    Because the stimulus driven impact of the rapid growth of tire and other rubber products' output,in recent years,the production and marketing of domestic rubber chemicals appear to increase,and the specific production and marketing conditions are as follows: 1.Rapid Growth of Chemicals Output From 2009 to 2010,in China an upsurge of expanding or building new rubber chemicals equipment was raised.These equipment were planned to be put into production in 2010 with newly increased production capacity of about 120,000 tons,among which there were 40,000 tons antioxidant 4020,50,000tons accelerator M,and about 40,000 tons other Chemicals.In 2010,the total output was 701,000 tons,with year-on-year growth of 17.8% or so.In 2010,the total sales volume of domestic rubber chemicals were 13 billion yuan,and the export volume was about 180,000 tons,basically the same with that in 2009.See the statistics of domestic rubber chemicals output from 2009 to 2010 in Table 1.

  11. Air quality measurements-From rubber bands to tapping the rainbow.

    Science.gov (United States)

    Hidy, George M; Mueller, Peter K; Altshuler, Samuel L; Chow, Judith C; Watson, John G

    2017-06-01

    It is axiomatic that good measurements are integral to good public policy for environmental protection. The generalized term for "measurements" includes sampling and quantitation, data integrity, documentation, network design, sponsorship, operations, archiving, and accessing for applications. Each of these components has evolved and advanced over the last 200 years as knowledge of atmospheric chemistry and physics has matured. Air quality was first detected by what people could see and smell in contaminated air. Gaseous pollutants were found to react with certain materials or chemicals, changing the color of dissolved reagents such that their light absorption at selected wavelengths could be related to both the pollutant chemistry and its concentration. Airborne particles have challenged the development of a variety of sensory devices and laboratory assays for characterization of their enormous range of physical and chemical properties. Advanced electronics made possible the sampling, concentration, and detection of gases and particles, both in situ and in laboratory analysis of collected samples. Accurate and precise measurements by these methods have made possible advanced air quality management practices that led to decreasing concentrations over time. New technologies are leading to smaller and cheaper measurement systems that can further expand and enhance current air pollution monitoring networks. Ambient air quality measurement systems have a large influence on air quality management by determining compliance, tracking trends, elucidating pollutant transport and transformation, and relating concentrations to adverse effects. These systems consist of more than just instrumentation, and involve extensive support efforts for siting, maintenance, calibration, auditing, data validation, data management and access, and data interpretation. These requirements have largely been attained for criteria pollutants regulated by National Ambient Air Quality Standards, but they are rarely attained for nonroutine measurements and research studies.

  12. A Rubber Band Ethics Model for Computing and Information Technology Practices

    Directory of Open Access Journals (Sweden)

    Mahmoud Mahmoud

    2006-01-01

    Full Text Available An innovative model for analyzing and describing the role of ethics and the manner in which it is applied in the general field of information technology is presented. Current practices and existing behavior rules that are related to economical and social issues are discussed with specific reference to computing technologies such as the internet. A theoretical model for computing and controlling drifts in ethical practices is then delivered to account for continuously changing socio-economical factors. The circle-ellipse model used proved to be a new and innovative yet simple way for predicting and analyzing ethics in an ever developing environment.

  13. Is the universe really made of tiny rubber bands? a kid's exploration of string theory

    CERN Document Server

    Lane, Shaun-Michael

    2014-01-01

    This book explores the fascinating world of string theory and quantum physics from a kid’s perspective. Originally published as an interactive text, it soon became an international best seller on Apple’s iBooks store and has been number one in the category of string theory on iTunes for the past two years. It is now available for the first time in print form. Fully illustrated and annotated. This is the black and white version.

  14. Devulcanization of ground tire rubber: Physical and chemical changes after different microwave exposure times

    OpenAIRE

    P. S. Garcia; F. D. B. de Sousa; J.A. Lima; S. A. Cruz; C. H. Scuracchio

    2015-01-01

    Microwave devulcanization is known to be a promising and an efficient rubber recycling method which makes possible for the rubber to regain its fluidity, and makes it capable of being remolded and revulcanized. The focus of this work is to understand the physical and chemical changes that occur in the ground tire rubber after different microwave exposure periods. For this purpose chemical, thermal, rheological and morphological analyses were performed on the tire rubber, which contains natura...

  15. Optimisation of rubberised concrete with high rubber content: an experimental investigation

    OpenAIRE

    Raffoul, S.; Garcia, R; Pilakoutas, K.; Guadagnini, M.; Flores Medina, N.

    2016-01-01

    This article investigates experimentally the behaviour of rubberised concrete (RuC) with high rubber content so as to fully utilise the mechanical properties of vulcanised rubber. The fresh properties and short-term uniaxial compressive strength of 40 rubberised concrete mixes were assessed. The parameters examined included the volume (0–100%) and type of mineral aggregate replacement (fine or coarse), water or admixture contents, type of binder, rubber particle properties, and rubber surface...

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

    OpenAIRE

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

    2011-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Akihiro; Ohtori, Yasuki; Yabana, Shuichi; Hirata, Kazuta [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Abiko Research Lab

    1999-04-01

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

  18. Performances Evaluation of a Novel Hadoop and Spark Based System of Image Retrieval for Huge Collections

    Directory of Open Access Journals (Sweden)

    Luca Costantini

    2015-01-01

    Full Text Available A novel system of image retrieval, based on Hadoop and Spark, is presented. Managing and extracting information from Big Data is a challenging and fundamental task. For these reasons, the system is scalable and it is designed to be able to manage small collections of images as well as huge collections of images. Hadoop and Spark are based on the MapReduce framework, but they have different characteristics. The proposed system is designed to take advantage of these two technologies. The performances of the proposed system are evaluated and analysed in terms of computational cost in order to understand in which context it could be successfully used. The experimental results show that the proposed system is efficient for both small and huge collections.

  19. A New Pixels Flipping Method for Huge Watermarking Capacity of the Invoice Font Image

    Directory of Open Access Journals (Sweden)

    Li Li

    2014-01-01

    Full Text Available Invoice printing just has two-color printing, so invoice font image can be seen as binary image. To embed watermarks into invoice image, the pixels need to be flipped. The more huge the watermark is, the more the pixels need to be flipped. We proposed a new pixels flipping method in invoice image for huge watermarking capacity. The pixels flipping method includes one novel interpolation method for binary image, one flippable pixels evaluation mechanism, and one denoising method based on gravity center and chaos degree. The proposed interpolation method ensures that the invoice image keeps features well after scaling. The flippable pixels evaluation mechanism ensures that the pixels keep better connectivity and smoothness and the pattern has highest structural similarity after flipping. The proposed denoising method makes invoice font image smoother and fiter for human vision. Experiments show that the proposed flipping method not only keeps the invoice font structure well but also improves watermarking capacity.

  20. Huge mucinous cystadenoma of ovary, describing a young patient: case report

    Directory of Open Access Journals (Sweden)

    Soheila Aminimoghaddam

    2017-08-01

    Conclusion: Ovarian cysts in young women who are associated with elevated levels of tumor markers and ascites require careful evaluation. Management of ovarian cysts depends on patient's age, size of the cyst, and its histopathological nature. Conservative surgery such as ovarian cystectomy or salpingo-oophorectomy is adequate in mucinous tumors of ovary. Multiple frozen sections are very important to know the malignant variation of this tumor and helps accurate patient management. Surgical expertise is required to prevent complications in huge tumors has distorted the anatomy, so gynecologic oncologist plays a prominent role in management. In this case, beside of the huge tumor and massive ascites uterine and ovaries were preserved by gynecologist oncologist and patient is well up to now.