Advanced Materials Research Vols. 622-623

Abstract: This study aimed to apply Taguchi method and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to optimize multiple qualities of needlepunched nonwoven fabrics with the fewest experiments. The quality characteristics are tear strength of machine direction (MD)/ cross machine direction (TD) and tensile strength of MD/TD. From nine experiments based on the L9 orthogonal array, the swing rate of the cross-lapper machine is 1500 rpm, the delivery rate of the cross-lapper machine is 15 cm/min, the depth of the needle penetration is 14 mm, and the punch density is 60 punches/cm2 were found to be the optimal processing parameters. Finally, ten confirmation experiments were executed to ensure the reliability and reproducibility of the TOPSIS predicted optimal conditions with a 95% confidence interval for the needlepunched nonwoven fabrics.

Abstract: Nowadays, step reduction in the manufacturing process is an important issue because it reduces both the cost and time. The objective of this research is to reduce the steps used in the cold forging process of a socket head screw from 3 steps (existing design) to 2 steps (new design). The commercial FEM (Finite Element Method) software was used for simulating the values of flow line, forging force and die stress, which were then used to determine part quality and tool life. The results have shown that the simulated values of 2-step design are similar to 3-step design.

Abstract: The appearance of pilotage system has brought unprecedented convenience and innovation to ship pilotage. however, these systems also brought some potential risks, such as the limitations of these data timeliness, reliability, stability of the system and so on. Pilotage is a system engineering ,which related to both human influence and external factor .A sole factor is likely to generate enormous losses, safety is most important part of pilotage. In order to ensure the safety of the ship’s pilotage .Comprehensive assessment of the pilotage system is necessary, of the ship. Forthputting the fuzzy comprehensive evaluation method,this paper establish the assessment system, and take comprehensive performance assessment of the pilot system, which entitled us a digital evaluation of the pilot system.

Abstract: Oil palm empty fruit bunch (OPEFB) is a potential source of cellulose which can serve as a promising raw material for the production of ethanol. The increasing interest on use of lignocellulosic waste for bioconversion to fuels and chemicals are justifiable as these materials are low cost, renewable and widespread sources of sugars. The objective of the present study was to determine the effect of NaOH concentration, reaction temperature and reaction time for alkali pretreatment to increase the amount of cellulose for hydrolysis to achieve high glucose yield. Batch reactions were carried out under various reaction temperature, reaction time and NaOH concentration. Response Surface Methodology (RSM) was followed to optimize the alkali pretreatment in order to obtain high amount of cellulose (%). The optimum reaction temperature, reaction time and NaOH concentration were found to be 130 ˚c, 40 min and 15% (w/v), respectively. The maximum value of cellulose was obtained 68.8% by using the above condition. 19.96 g/L glucose was achieved when reaction was carried out at 130 ˚c for time period of 90 min when 6% (w/v) of H₂SO₄ concentration maintained.

Abstract: This research is study of the air conditioning by used fuzzy logic control to analysis. It will take into account the energy savings and the room temperature remained in range of comfort zone for the resident's satisfaction. To control % AC compressor and fan speed. The system was simulated and designed simulation model of fuzzy logic controlled on Matlab program to monitor energy consumption and temperature of the room. The results indicate that thermal comfort of the room together with energy saving can be obtained through fuzzy logic controlled .At a temperature setting of 25 °C and defined heat load in the room, the energy saving for the system is calculated to 30.77 % for fuzzy controllers when compared with on-off condition.

Abstract: Thermal stress points in an inductor can cause insulation deterioration and ageing, leading to winding faults, while high magnetic flux causes interference. In this paper, the thermal and magnetic behaviors of inductors with different winding geometries are investigated using the Finite Element Method (FEM) based on 2-Dimension and 3-Dimension model of an inductor. Inductors with different winding geometries have different thermal envelopes and the geometry with the slowest thermal transition has fewer thermal stress points potentially reducing winding faults at the conductor. Furthermore, slow thermal transition would result in greater magnetic field coverage with no magnetic flux outside boundary of the inductor.

Abstract: Due to the pressure in a shop floor to complete a set of jobs within due date, all the materials are to be processed within a minimum possible time. This is linked to the problem of finding an optimal sequence in terms of total completion time (Make Span) for processing ‘n’ jobs in ‘m’ processing centers in the shop floor. The problem is NP hard as the total number of sequences is (n!) for a permutation flow shop scheduling problem. In the shop floor, due to the limitation in the computing capabilities and computer knowledge, still the Classical heuristics are popular because of their simplicity. However, in most of the cases, we get only one sequence except in CDS algorithm where the best sequence is selected from (m-1) alternatives. This paper deals with optimization of total material processing time in a manufacturing flow shop using the concept of Dummy Machine in one Heuristics proposed by the authors, based on the Pascal’s triangle. In such cases, more sequences having make spans which may be optimal/ near optimal can be obtained. This results in optimization of total material processing time and enables the shop floor supervisor to complete the jobs within a minimum possible time.

Abstract: Study of the guided waves in piezoelectric cylinders based on a semi-analytical finite element method is presented. In the study, the dispersion equation was formulated as a generalized eigenvalue problem by treating mechanical displacements and electric potential with one dimensional quadratic finite element model through the thickness of the cylinder. Here the general eigenvalue problem is depended on three parameters, namely, the frequency, the axial wave number and the circumferential wave. A non-integer circumferential wave is introduced here for studying the guided spiral wave. A wave spectrum surface is generated to incorporate the guided spiral waves. Cylinders having different geometry and electric boundary conditions are studied but only the results for a thin cylinder with closed electric boundary conditions are presented.

Abstract: Besides relying on electronically actuated valves, there is a need to have a mechanically actuated valve and a warning system as second layer of safety in-case of electronic malfunction. The specific process for which optimization is carried out, is the process of nitrous oxide generation from ammonium nitrate. The key challenge in the process was maintaining temperatures below 200°C, as above this temperature ammonium nitrate becomes explosive and hence safety risks are involved. The secondary objective was to maintain temperatures above 170°C, as below this temperature the reaction does not proceed. In this paper we have tried to fulfill these objectives by employing a bi-metallic valve and a warning system having bi-metallic strip which will bend at higher temperatures, thus serving our primary purpose of self-actuation. However the key constraint in determining the dimensions of the valve and the warning system is a desirable deflection of bi-metallic strip. To optimize these parameters we have employed non-linear FEA and thermo-structural coupled FEA, and this paper reflects on the process employed in achieving the same.

Abstract: The semiconductor final testing scheduling problem (SFTSP) is a variation of the complex scheduling problem, which deals with the arrangement of the job sequence for the final testing process. In this paper, we present an actual SFTSP case includes almost all the flow-shop factors as reentry characteristic, serial and batch processing stages, lot-clusters and parallel machines. Since the critical equipment needs to be utilized efficiently at a specific testing stage, the scheduling arrangement is then playing an important role in order to reduce both the makespan and penalty cost of all late products in total final testing progress. On account of the difficulty and long time it takes to solve this problem, we propose a multi-objective optimization approach, which uses a lot-merging procedure, a new job-based encoding method, and an adjustment to the non-dominated sorting genetic algorithm II (NSGA-II). Simulation results of the adjusted NSGA-II on this SFTSP problem are compared with its traditional algorithm and much better performance of the adjusted one is observed.