Influence of Surface Condition, Duration of Molding, Pressure and Temperature upon Bond Strength between Components of Tire Casings

1959 ◽  
Vol 32 (2) ◽  
pp. 503-512
Author(s):  
V. A. Pinegin ◽  
S. A. Vasil'eva ◽  
L. M. Kepersha

Abstract As a result of the above experiments it is shown that the bond strength between components of casings where 100% synthetic rubber is used, may be significantly increased: 1) by maintaining the freshness of the surfaces being plied up by keeping standing to a minimum, by freshening the surfaces by fine (‘velvet’) buffing, and by applying a thin and uniform layer of bonding agent to the previously heated surfaces; 2) by increasing the specific molding pressure during plying up; 3) by increasing the specific pressure upon the constructions during vulcanization; 4) by increasing the duration of action of the specific molding pressure during plying up; 5) by raising the temperature of the components being plied up. The rational exploitation of these points undoubtedly has an important effect and will ensure the improvement of the quality of the finished articles, particularly where 100% synthetic rubber is used.

2020 ◽  
Vol 8 (02) ◽  
pp. 49-54
Author(s):  
Salil Mehra ◽  
Ashu K. Gupta ◽  
Bhanu Pratap Singh ◽  
Mandeep Kaur ◽  
Ashwath Kumar

Abstract Introduction The aim of the current study was to evaluate shear bond strength of resin composite bonded to Theracal LC, Biodentine, and resin-modified glass ionomer cement (RMGIC) using universal adhesive and mode of fracture. Materials and Methods A total of 50 caries-free maxillary and mandibular molars extracted were taken; occlusal cavities were prepared, mounted in acrylic blocks, and divided into five groups based on the liner used. Group 1: Biodentine liner placed into the cavity and bonding agent and resin composite applied after 12 minutes. Group 2: Biodentine liner placed into the cavity and bonding agent and resin composite applied after 14 days. Group 3: RMGIC liner placed into the cavity and bonding agent and resin composite applied immediately. Group 4: RMGIC liner placed into the cavity and bonding agent and resin composite applied after 7 days. Group 5: Theracal LC liner placed into the cavity and bonding agent and resin composite applied immediately. Each sample was bonded to resin composite using universal adhesive. Shear bond strength analysis was performed at a cross-head speed of 0.1 mm/min. Statistical Analysis  Statistical analysis was performed with one-way analysis of variance and posthoc Bonferroni test using SPSS version 22.0. Results and Conclusion Biodentine liner when bonded immediately to resin composite showed minimum shear bond strength. RMGIC when bonded to resin composite after 7 days showed maximum shear bond strength. Mode of fracture was predominantly cohesive in groups having Biodentine and Theracal LC as liner.


2020 ◽  
Vol 124 (6) ◽  
pp. 738.e1-738.e8
Author(s):  
Rafael S. Assis ◽  
Fabiane Carneiro Lopes ◽  
Renato Roperto ◽  
Yara Teresinha Corrêa Silva Sousa ◽  
Elisabeth Helena Brazão ◽  
...  

2017 ◽  
Vol 6 (3) ◽  
pp. 26-32
Author(s):  
G P Deo ◽  
S K Shrestha ◽  
I N Shrestha

To compare the efficacy of epidural butorphanol and tramadol for post operative analgesia in lower limb surgeries. Randomized, controlled, double blind, prospective study conducted at Department of Anaesthesia and Critical Care, Chitwan Medical College from September 1st 2015 to August 31st 2016. 60 patients of ASA Grade I and II of either sex, aged between 18-65 years willing for epidural analgesia for post operative analgesia were included in the study. They were divided into two groups: Group B- Butorphanol group and Group T- Tramadol group. Subjects of Group B received 2mg of Butorphanol and 0.25% Bupivacaine making a total volume of 10 ml and that of Group T received 100mg of Tramadol and 0.25% Bupivacaine also making a total volume of 10 ml. Analgesic efficacy was assessed by Visual Analogue Scale (VAS). The onset and duration of analgesia along with side effects were also assessed. The quality of analgesia was studied using time to independent mobilization and overall patient satisfaction. Total number of patients was 60, of ASA Grade I and II, aged between 18-65 years. The mean age of patients in Group B was 42.6±11.7 years and 46.1±11.2 years in Group T. Time of onset of analgesia after epidural injection was 7.4±0.9 minutes in Group B and 12.7±1.5 minutes in Group T and the difference was found to be statistically significant. Duration of analgesia was 317.1±99.1 minutes and 438.8±136.6 minutes in Butorphanol and Tramadol groups respectively which was also statistically significant. Sedation was significantly higher in butorphanol group whereas nausea and vomiting was higher in tramadol group. Quality of analgesia in terms of patient satisfaction was better with epidural butorphanol. Both epidural tramadol and butorphanol were effective in relieving post operative pain however butorphanol had lesser side effects and greater patient satisfaction compared to tramadol but the duration of action was relatively short.


2019 ◽  
Vol 809 ◽  
pp. 341-346 ◽  
Author(s):  
Torsten Thäsler ◽  
Jens Holtmannspötter ◽  
Hans Joachim Gudladt

The surface condition of carbon fibre reinforced plastic (CFRP) substrates is decisive to obtain high bond strength and lifetime of adhesively bonded parts. Those surfaces were adjusted in terms of their microscopic topography by means of peel plies and release foils. The subsequent surface treatment via atmospheric pressure plasma jet or vacuum blasting allowed the modification of the microscopic roughness as well as the surface chemistry. Those configuration were assessed using surface analytic methods as well as quasi-static and cyclic fracture tests on single lap shear specimens. The microscopic surface roughness, if at all, only showed a small influence on the bond strength. Despite release agent residues, fracture was found within the fiber-matrix interface, which caused difficulties in evaluating the effect of surface pretreatments on the adhesion strength. Fatigue tests revealed a lifetime reduction of uneven microscopic rough surfaces, which was assigned to stress concentrations at the tip of asperities. The crack propagation was accelerated in case of release agent residues. If surfaces were free of contaminations, no differences between microscopically smooth and slightly structured surfaces were found. Overall, fatigue testing on single lap shear specimens showed an increased sensitivity with regard to the assessment of surface morphology.


1959 ◽  
Vol 32 (3) ◽  
pp. 898-906
Author(s):  
R. V. Uzina ◽  
L. S. Gromova ◽  
S. A. Vasil'eva

Abstract In selecting methods for determination of rubber to cord bond strength it is necessary to consider the factors which are subject to variation in the system— the type of cord, the composition of the vulcanized rubber, or the composition of the impregnant. The selection (composition) of the methods of assessment of bond strength was carried out in the present study while keeping the type of cord and the rubber compositions constant ; only the composition of the impregnant was varied. Up to the present there has been no single laboratory method for evaluating rubber to cord bond strength for the determination of the service quality of rubber-fabric structures. The bond strength in such a system is assessed in the majority of cases by the use of a series of methods. The existing methods may be systematized according to the nature of the deformation (static or dynamic), the nature of the specimen (with single thread of cord or with cord fabric) and so on. We adopted the following classification of methods: 1). Determination of bond strength of a single thread of cord with the rubber; 2). Determination of bond strength of rubber to fabric model specimens. Determination of bond strength of a single thread of cord with rubber is an exceptionally widely used type of testing in the rubber industry. It is based either on the principle of stripping of a single thread of cord from the rubber under pressure, or on the principle of pull-out of a thread of cord from a rubber specimen.


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