Thermoelastic properties nanocomposite chloroprene of rubber with montmorilonit

The problem that arises during the operation of tires is cyclic deformation, in which there is a conversion of mechanical energy into heat. However, due to the low thermal conductivity of rubber, repeated cyclic loads of products based on them lead to heating, which is due to the phenomenon of mechanical hysteresis. The consequence is a deterioration of their performance over time and, as a consequence, a reduction in service life. The main method for increasing the interfacial interaction for ceramic fillers is to ensure the penetration of rubber molecules into the interplanar space (gallery) formed by the filler particles (intercalation), and the subsequent distribution of these nanoplates (exfoliation) to a thickness of several nanometers throughout the field. The aim of this work is to study the thermoelastic properties of rubbers made on the basis of nanosized mineral filler montmorillonite, which may indicate a way to solve the problem of their durability. It was investigate the influence of modified nanosize montmorilonit on thermoelastic properties of rubber composites on it basis. It is rotined that thermoelastic properties described a model, which takes into account holdings of local increase of tension for a rubber matrix and destruction of spatial net of nanoparticles with the increase of strein, which results in exotherms which show up as a result of friction between the filler particles. Quantitative analysis of the thermoelastic properties of rubber nanocomposites provides additional confirmation of the concept of the reinforcement factor, which depends on the deformation, and determines the thermoelastic properties of nanocomposites for the whole range of relative elongations.

Numerical Modeling of the Effects of Fiber Packing and Reinforcement Volume Ratio on the Transverse Elasticity Modulus of a Unidirectional Composite Material Glass / Epoxy

Composite materials are very widely used in the manufacturing of structures because of their specific mechanical properties. However, they are characterized by heterogeneity and anisotropy and they present great challenges in designing and also in predicting their behavior by using the numerical simulation. The unidirectional composite material has a more relevant property which is the transverse elasticity modulus E2. The determination of E2 is still interesting researchers because of the diversity of results obtained by several models and approaches. This study aims to predict the transverse elasticity modulus E2 of a unidirectional Glass/Epoxy composite material, the effect of the arrangement fibers on the transverse elasticity modulus and predict the values of the reinforcement factor used in the Halpin-Tsai model. To do so first we adopted the micromechanical approach, which is accurate but requires much computing, and we used a calculation code based on FEM method and considered two parameters to vary, which are the volume fraction of fibers and the distribution of fibers. The obtained results of numerical modeling were tightly compared to those obtained by the available analytical models and the adopted approach can be used to predict the transverse elasticity modulus E2 and the reinforcement factor ξ.

Analisis Perilaku Pekerja Gondola PT. Waringin Megah Proyek Springhill Condotel Lampung

<p>This research was conducted at Springhill Condotel Lampung to find out and dig deeper into the behavior of gondola workers. This study used a qualitative study approach. Information collection and retrieval is obtained through observation, in-depth interviews, and document studies. The supporting factors that have not supported the gondolier workers to behave safely are knowledge of the hazards, the bad perception about Personal Protective Equipment (PPE), and the undisciplined attitude of the workers Using PPE. On the enabling factor, it was found out that the availability of PPE and the existing rules in the project enables gondola workers to behave safely, but still found unsafe acts. And on the reinforcement factor, less supervision was found from supervisors and safety. Company to provide information about hazards of gondolas, tighten the control of PPE, and provide safe behavior training. Gondola workers to ask supervisors and OSH sections on things they do not know, change poor perceptions better about the use of PPE, and to improve negative attitudes in the use of PPE and regulations.</p>

Experimental Research for Scour Resistance of Basalt and Carbon Fiber Hydraulic Concrete

According to a series scour resistance experiment of basalt fiber and carbon fiber hydraulic concrete, in which different length and different volume ratio of basalt fiber and carbon fiber to compare to cement volume are mixed in the concrete, the scour resistance characteristics of hydraulic fiber concrete are analyzed in this paper. Experimental results show that basalt fiber and carbon fiber may enhance scour resistance of hydraulic concrete, and the volume ratio of fiber to compare to cement volume in concrete is the main reinforcement factor, but the influence of fiber length in concrete on the scour resistance of concrete is not obvious.