Abstract: This research studies the impact of maximum allowable stopping time for machining tools on the production-inventory policy under a variable tools lifespan and demand. A mathematical model is developed to determine the optimal maximal allowing stopping time, the inventory level, and the replenishment interval. A numerical example was conducted using an exhaustive searching method to show the implementation of our model. The results indicate that, compared to the traditional policy which only repairs and replace the broken tools, adopting a maximum allowable stopping time dramatically reduced the total production cost.
Abstract: MRE provides great potential for Malaysia, an emerging economy, to diversify its primary energy mix and ensuring the security of its energy supply. In this paper, the state-of-the-art of each MRE type is studied alongside hydrographical and geographical conditions of Malaysian waters. It is based upon this knowledge that an MRE scheme is proposed for Malaysia. However, introducing a complex MRE system into Malaysia’s energy pool requires in-depth understanding of key governing factors and the dynamic behaviours of its implementation using a systemic approach. Results from system dynamics modelling have identified key-enablers to fast-track the implementation of MRE in Malaysia.
Abstract: In this study, the principal component analysis (PCA) was used to analyze and classify the electric arc furnace oxidizing slag based on physical properties. The results indicated that about 91.44 % information could be explained using the previous four PC. The Los Angeles abrasion test (LAAT) and loss of sodium sulfate soundness test (LSSST) mainly contributed to the first PC, meanwhile the saturated surface-dry specific gravity (SSDSG) contributed mainly to the second PC. The significant physical properties of EAF slag including LAAT, LSSST, and SSDSG could be identified according to PCA. According to the two dimension classification using PC1 and PC2, the 60 samples could be approximately classified into two groups. They could be also classified into two groups in three dimension classification.
Abstract: In the last few years, the automotive industry has adopted the Six Sigma program aiming the performance increasing in the competition market. This tool is used as basis of quality control and strategic planning for production, providing significant improvements in direct and indirect costs of production. This paper provides a successful result obtained in an automotive industry in which the quality had been improved through the strategy proposed by Six Sigma. This company, after applying the Six Sigma methodology, had successfully reduces the amount of defects in the automotive seats in the assembly line. After the implementation, the company achieved higher quality process and its costs decreased, reducing to less than 50 % the number of seats with defects. The study contributes to the management practices, by identifying new applications with Six Sigma and further analysis of manufacturing with financial performance as well as to discuss the implications of these findings for practice and for future research.
Abstract: The objective of this paper is aimed at determining the sequential pattern of a newly mixed-models assembled cars entering into the final inspection lines so that the required production rate of each model can be obtained as specified. The inspection lines are consisted of three parallel conveyor lines and each line is designed to be able to inspect any car models. One can imagine that each model with different inspection details will definitely consume different lead time to complete the job. As a result, the model with short lead time can be finished faster than one with longer lead time. Thus, by the end of each inspection hour, it is difficult to maintain the exact production rate of each product. The unfinished model will become a back order and will be completed in the next hour and therefore the rest of the schedule will be affected. Without knowing of the fixed rate launching algorithm, the exact production rate of each model for each working hour can not be met.
Abstract: Small type gasoline engine has the advantage of lightweight and low energy, but its emissions of carbon dioxide will lead to global greenhouse gas growing. This study aims to test the performance of the cultivator between different soil and tools. Comparative test electric and gasoline engine type cultivator contains the following items: energy consumption, carbon dioxide emissions in the job and the operator heart rate change. The results show that the width of 60 cm and depth of 3 cm operating conditions weeding, electric cultivators and gasoline engine cultivator average turn time was 2.9 seconds and 3.3 seconds, with an average forward speed were 0.535 and 0.515 m/s. Comparison of the time and forward speed cornering, the electric cultivator superior gasoline engine cultivator, and can successfully achieve high torque output characteristics weeding needed. Energy consumption and carbon emissions test data show that the loam fields, the average power consumption cost of NT $ 21.2/ha; carbon dioxide emissions by an average of 26 kg/ha. This result shows that energy consumption in the consideration of the performance of carbon dioxide emissions, electric cultivators have lower costs. The test results are displayed in the field; the electric cultivator operator heart rate is lower than the gasoline engine cultivator and has significant difference statistically. Therefore, in the field of long-term operating conditions, the electric cultivator helps reduce physical exertion and operator fatigue.
Abstract: Using system dynamics, this paper investigates the feasibility of implementing an integrated infrastructure for Electric Cars (EC) in Malaysia by understanding the intrinsic relationships, compounded effects and dynamics of policies, public knowledge, technology maturity, private investment and network of support infrastructure required upon its deployment in Malaysia. All key enablers are assumed to have a feedback relationship with the demand and the scale of overall EC sold. From the results, it can be concluded that governmental subsidies, environmental policies and effective marketing strategies are needed to support the EC market along technological advancements such as improvement in the EC's battery life.
Abstract: To eliminate the introduction of invasive marine species and the disadvantages of ballast water (BW) treatment systems a new concept in ship design was developed to be alternative of ballast water system. Non-Ballast ships were rarely mentioned in China even they were studied widely worldwide. In this paper, the different types of non-ballast water ship were reviewed, to be classified in order to facilitate the study of such types of vessels and serve as a base for the development.
Abstract: This paper describes the work performed on a small-scale dryer designed to allow agricultural product to be dried by farmers via usage of slanted plates for grains transportation. This work involves the prototype design, computational simulation using Comsol Multiphysics and study of the results. The computational simulation results are plotted in temperature contour-plots based on the prototype modelling and boundary conditions. The results illustrate the difference in opening and closing of grains inlet and also effects of the temperature distribution within the dryer. Air-flow relative humidity is also introduced to allow observation of the drying air-flow on the grains. The simulation results are shown and elaborated here. From the results, it is evident the grains can be dried as the injected heated air-flow is projected onto the plates. It can also be concluded here that farmers may need to close the grains inlet of the dryer to prevent heat loss and non-uniform distribution of heat.
Abstract: The article deals with the concept of solar photovoltaic systems use in power supply systems. An analysis of local solar resources potential has been carried out, and optimal orientation points of radiant heat absorbing photovoltaic panels have been chosen to achieve maximum energy performance. Simulation of electric power systems having different configurations has been implemented using the software program Homer. It has been stated that a combination of solar and diesel energy systems is considered to be an optimal solution under the weather conditions of Montenegro. The systems working together make it possible to reduce maintenance costs significantly and adjust capacity generation schedule with due account for energy consumption features to a maximum extent. This allows generating electric power at less cost and results in a more reliable and continuous power supply without failures for a consumer chosen.