Effect of Cooling Medium on Fracture Toughness of Rotomoulded Product

In day-to-day life, usage of plastics is numerous. It offers variety of benefits compared to other materials in various sectors like house hold applications, agricultural industry, and packaging, etc. There are numerous methods for processing plastics. These include: blow moulding, injection moulding, rotational moulding, transfer moulding and thermoforming. Rotational moulding is a competitive alternative to other plastic manufacturing process, since it offers designers an opportunity to achieve an economic production of stress free products. Many products made by rotational moulding process using linear low density polyethylene (LLDPE) are widely used in outdoor applications such as boats, over head tanks, and car body parts etc. In such applications, fracture properties are considered to be critical from the quality characterization point of view. Selection of appropriate cooling medium plays vital role to enhance the quality of rotomolded products. In this paper, an attempt has been made to investigate the effect of cooling medium on fracture toughness of the rotationally moulded products. Fracture tests are carried out on a compact tension (CT) test specimens prepared as per the ASTM D 6068 (2012). The tests are performed on a universal testing machine. R-curve method is used to determine the fracture toughness (JIC) of rotomoulded products. From the experimental results it is found that rapid cooling method favours better fracture toughness of rotomoulded products. Therefore, it is recommended to use faster cooling aids like water cooling in rotational moulding process to achieve highest fracture toughness.</jats:p

Investigation of Melt Flow Index and Impact Strength of Foamed LLDPE for Rotational Moulding Process

AbstractRotational molding of foamed polyethylene has increasingly become an important process in industry because of its thicker walls, low sound transfer, high stiffness and good thermal insulation. However, the foaming process of polyethylene during rotational molding has not been well studied. The focus of thisarticle is to assess the rotomoldability of foamed polyethylene and to investigate how LLDPE foam influence the process of rotational molding and the final product quality. Rotational molding experiments are carriedout in a laboratory scale biaxial machine. Impact tests and melt flow property are performed on the rotationally molded parts. It is found that the MFI and impact strength of rotomoulded product increases as the foam percentage increases up to 6% after which both decreases. Therefore it is concluded that 6% of foam is the optimum level to obtain sufficient melt flow index and better impact strength

Flattening is an Improvement

) James Riely 1 and Jan Prins 2 1 DePaul University 2 University of North Carolina at Chapel Hill Abstract. Flattening is a program transformation that eliminates nested parallel constructs, introducing flat parallel (vector) operations in their place. We define a sufficient syntactic condition for the correctness of flattening, providing a static approximation of Blelloch&apos;s &quot;containment&quot;. This is acheived using a typing system that tracks the control flow of programs. Using a weak improvement preorder, we then show that the flattening transformations are intensionally correct for all well-typed programs. 1 Introduction The study of program transformations has largely been concerned with functional correctness, i.e. whether program transformations preserve program meaning. However, if we include an execution cost-model as part of the programming language semantics, then we can ask whether program transformations additionally preserve or &quot;improve&quot; program performance. One progra..