Linear-nonlinear stiffness responses of carbon fiber-reinforced polymer composite materials and structures: a numerical study

The stiffness response or load-deformation/displacement behavior is the most important mechanical behavior that frequently being utilized for validation of the mathematical-physical models representing the mechanical behavior of solid objects in numerical method, compared to actual experimental data. This numerical study aims to investigate the linear-nonlinear stiffness behavior of carbon fiber-reinforced polymer (CFRP) composites at material and structural levels, and its dependency to the sets of individual/group elastic and damage model parameters. In this regard, a validated constitutive damage model, elastic-damage properties as reference data, and simulation process, that account for elastic, yielding, and damage evolution, are considered in the finite element model development process. The linear-nonlinear stiffness responses of four cases are examined, including a unidirectional CFRP composite laminate (material level) under tensile load, and also three multidirectional composite structures under flexural loads. The result indicated a direct dependency of the stiffness response at the material level to the elastic properties. However, the stiffness behavior of the composite structures depends both on the structural configuration, geometry, lay-ups as well as the mechanical properties of the CFRP composite. The value of maximum reaction force and displacement of the composite structures, as well as the nonlinear response of the structures are highly dependent not only to the mechanical properties, but also to the geometry and the configuration of the structures

The Development Of High Temperature Recirculating Pump (HTRP) For Energy Savings In An Incinerator.

Tremendous increase ingeneration of Municipal Solid Waste (MSW) has become a major concern for the Malaysian government as the country experiencing rapid development. It was estimated about 16000 tones/day MSW is produced at national level and in Kuala Lumpur alone about 2500 tones/day

A new degree six modified chordal ring network topology

The performance of a parallel or distributed network depends on the design of its interconnection topology. One good network interconnection topology that has been the focus of various researchers is the chordal ring. In this paper, a new degree six modified chordal ring is presented, the optimised degree six 3-modified chordal ring (CHR6o3), with the aim of comparing its performance parameters in terms of optimal diameter and optimal average path length to existing degree six chordal rings. Formulae to generate the data for each different chordal ring were derived from its corresponding tree visualisation or used from previous work. Network sizes tested were from 1200 to 12000 nodes. Large networks of CHR6o3 were shown to perform better than those of previous degree six chordal rings. This gives CHR6o3 an added advantage for its implementation in large distributive networks, such as Fibre to the Home (FTTH) networks, since it offers redundancies at higher network layers

Locus of control, attributions and impression management in the selection interview

Surprisingly little is known about the ways in which candidates create positive impressions during employment interviews. Three studies are presented which investigate how candidate and interviewer locus of control influence preferences for three categories of explanations proffered by candidates during graduate recruitment interviews. In Study 1, we asked 139 undergraduate students and 37 personnel managers to rate internal-controllable, internal-uncontrollable and externaluncontrollable candidate attributions for hypothetical past events according to the likelihood of each producing a positive impression during a selection interview. Students also completed Rotter's Locus of Control questionnaire and the Interview Behaviour Scales. Students and personnel managers rated internal-controllable attributions most likely to create a positive impression. However, students with an external LoC rated external-uncontrollable explanations and internal-controllable explanations as being equally likely to convey a positive impression. In Study 2 a group of 62 candidates applying for actual positions with a company completed the same attribution questionnaire prior to first-stage interviews. Interviewer ratings of candidate performance correlated positively with ratings of internal-controllable explanations (r =.36, p< .001). In Study 3, a sample of 103 experienced interviewers completed the attribution questionnaire and the WLOC. All interviewers rated internal-controllable attributions most likely to convey a positive impression of a candidate. However, locus of control mediated preference for candidate attributions such that ‘External’ interviewers rated external-uncontrollable attributions significantly more likely to convey a positive impression than ‘Internal’ interviewers. The implications of these findings for impression management and interview selection decisions are discussed

Radiation grafted natural fibres functionalized with alkalised amine for transesterification of cottonseed oil to biodiesel

Poly(glycidyl methacrylate) grafted Linum usitatissimum (flax) fibers functionalized with diethylamine (DEA) groups followed by alkalisation were prepared and used as a heterogeneous catalyst for production of biodiesel. Particularly, the new basic catalyst was used for transesterification of cottonseed oil using different molar ratios with methanol and various reaction temperatures. The gas chromatography analysis was used to confirm the conversion of the cottonseed oil to biodiesel. The transesterification reaction temperature affected the conversion percentage significantly. The highest conversion was obtained at 60 °C. In addition, the oil/methanol ratio in the reaction mixture of 1:33 resulted in the highest conversion ratio reaching about 97 %. These results suggest that the alkaline organic catalyst prepared in this study has a potential for application in biodiesel production

Modeling of Tyre-Clay Soil Interaction via Quasi-Static Moving Boundary Displacement Method

A vehicle mobility model has been developed using energy principles and a quasi-static moving boundary displacement method. For a given condition of both tyre and terrain characteristics, the model calculates the contact length, the slip rate, the traction efficiency and the drawbar pull. The effect of tread configuration is also included in calculating the slip rate. A numerical example is given to demonstrate the capability of the new developed mode. The model's predictions are also compared with the experimental results in the laboratory tests and a good agreement is obtained