Papers by Keyword: Full Factorial Design

Abstract: The delignification of biomass serves as an important pre-treatment step for the subsequent valorization of the three key lignocellulosic components (i.e. cellulose, hemicellulose, and lignin). Among the delignification methods, much effort on research currently has been on organosolv processes, especially on ethanol organosolv, due to its advantages. This study investigated the effects of solid-to-liquid ratio and solvent concentration on the ethanol organosolv delignification from sugarcane bagasse. The extractives-free bagasse was delignified for 4 hours at 95°C (open reflux) with 1.50% v/v sulfuric acid as catalyst at varied process parameters: 50-80% ethanol concentration, and 1/20 – 1/30 S/L ratio. The experimental results show that for a low ethanol concentration, delignification is more effective when a low S/L ratio is used. Conversely, a high ethanol concentration can be effectively carried out at a higher S/L ratio. Moreover both parameters investigated have a significant (p<0.05) individual effect on delignification, but their combined effect is of greater influence. A maximum lignin fraction yield of 30.28% and a pulp yield of 73.54% was obtained at an S/L ratio of 1:30 and a solvent concentration of 50% ethanol. A time profile study conducted at the best condition chosen showed that time has a positive effect on delignification. Delignification continued as time progressed with a 49.94% lignin fraction yield achieved at pulping time of 8 hours. The ethanol delignification of extractives-free bagasse followed a first-order reaction.

Abstract: Plasma Arc Machining is a metal cutting where conductor metal such as sheets metal are cut with plasma arc. Problem in plasma arc machining is the result of cutting has burr which is quite large due to the heat, resulting the surface roughness on the workpiece. This research aim to minimize the surface roughness of the stainless steel plate uses a design of experiment method with full factorial design. In this research, there are three factors, that are torch height, cutting speed, and electric current. Each factor has three levels. By using full factorial design, the number of treatments are 3³=27 trials. The results of the research on data processing analysis of variance show that the most influential factor on surface roughness is cutting speed with contribution value of 90.76% followed by two other factors, that is height torch with contribution value of 2.42% and electric current with contribution value of 0.23% and contribution value of noise by 6.59%. Then based on data processing robust design the optimum combination of parameters is obtained by using setting 1 mm torch height, 2400 mm/min cutting speed, and 30 A electric current. Based on the confirmation experiments, experiments with optimum parameter combinations can reach a gap noise of 2.283 dB. Therefore, the design of experiment for determining parameter setting plasma arc machining can determine the optimum combination of parameters to minimize the surface roughness.

Abstract: This research aims to identify the optimal condition of the zinc Zamak3 alloys' melting process using 2k full factorial design and its optimizer in Minitab 18 software. The evaluation results of the ANOVA test with a first-order model revealed that the change in both independent variables simultaneously resulted in a statistically significant alteration of the percentage of slag. The independent parameters also had an effect individually on the response. Additionally, the slag percentage reduction was increased significantly due to an elevation of the temperature. However, the change of flux type resulted in an overall alteration of the slag percentage more than the change of melting temperature. The response optimizer demonstrated that the optimal condition was the melting temperature of 500°C coupled with the ZinCrex EP7119 flux achieving the lowest slag percentage of 1.672%, with the 95% confidence interval ranging from 0.643% to 2.701%.

Abstract: Colonic drug delivery systems (CDDS) show several advantages for treatment of inflammatory bowel disease such as improving the clinical outcomes and minimizing side effects of corticosteroids. However, variation of the patient's gastrointestinal tract (GIT) in terms of transit time and pH causes the fluctuation of the drug releasing site in the GIT resulting in low therapeutic efficiency. Consequently, 3D-printing techniques have been applied for preparation of personalized colonic drug delivery systems in this study. Prednisolone was selected as a model drug and prepared in the form of a core tablet. Polylactic acid (PLA) and polyvinyl alcohol (PVA) were printed as a tablet housing and a drug control release plug, respectively. A two-factor full factorial model was utilized to design the experiment and partial least square regression (PLS) models were generated to reveal and predict drug release time of the system. From the results, only thickness of the PVA plug significantly affected the drug release at sampling times of 5, 6, 10, and 24 h. The relations between thickness of the plug and drug releases at 5, 6, and 10 h are quadratic but that of 24 h is linear. The relation between thickness of the plug and drug releases is quadratic. The drug could not be completely released in 24 h because the drug was entrapped by PVA gel. The search results show the possibility to utilize the PLS models to modify drug release time for individual patients. However, alteration of plug polymer is a suggestion to obtain complete drug release.

Abstract: Friction stir welding is most commonly used for joining aluminum alloy parts. After welding, residual stresses occurred in the welded joint caused by non-uniform cooling rate. Friction stir welding usually generates tensile residual stress inside the workpiece which affects the strength in addition to the fatigue life of materials. Compressive residual stress usually is beneficial and it can be introduced by mechanical surface treatment methods such as deep rolling, shot peening, laser shock peening, etc. In this research, deep rolling was used for inducing compressive residual stress on surface of friction stir welded joint. The residual stresses values were obtained from X-ray diffraction machine. Influence of three deep rolling process parameters: rolling pressure, rolling speed and rolling offset on surface residual stresses at the welded joint were investigated. Each factor had 2 levels (2³ full factorial design). The statistical analysis result showed that the rolling pressure, rolling speed, rolling offset, interaction between rolling pressure and rolling speed, interaction between rolling speed and rolling offset were statistically significant factors, with the most compressive residual stress value approximately -391.6 MPa. The appropriated deep rolling process parameters on surface residual stress of AA7075-T651 aluminum alloy friction stir welded joint were 1) rolling pressure about 150 bar 2) rolling speed about 1,400 mm/min 3) rolling offset about 0.1 mm.

Abstract: In this study, there are three machining parameters consist of spindle speed, feed rate and depth of cut which were conducted through full factorial with four center points to determine the effect of machining parameters on the surface roughness and verify whether there is curvature in the model for CNC face milling process in an automotive components manufacturer in Thailand. The workpieces used semi-solid die casted ADC12 aluminum alloy crankcase housing which they were performed by the ARES SEIKI model R5630 3-axis CNC vertical machining center and face milling cutter with diameter of 63 millimeters. The surface roughness of face-milled was measured by the surface roughness tester. It was found that the greatest main effect influence to surface roughness was spindle speed, followed by feed rate and depth of cut at significance level of 0.05.

Abstract: This study aims to investigate the effect of three factors, namely alumina trihydrate (ATH), montmorillonite (MMT) and irradiation dosage on the mechanical properties (tensile strength and elongation at break) of flame-retarded LDPE-EVA composites. In this study, full factorial design analysis was used to examine the effects of factors and their combination interactions on mechanical properties. ATH is the most significant factor in affecting the tensile strength of LDPE-EVA blends due to the poor compatibility effect between ATH particles and LDPE-EVA matrix. However, MMT is the least significant factor on tensile strength of LDPE-EVA composites. ATH was the most significant in affecting the elongation at break of LDPE-EVA blends. This is because the increasing of ATH amount in LDPE-EVA matrix could restrict the mobolity of polymer chains in LDPE-EVA matrix. However, the factor of irradiation dosage was found to be insignificant in affecting the elongation at break of LDPE-EVA blends.