CNC Milling of Medical-Grade PMMA

This study evaluates CNC milling parameters (spindle speed, depth of cut, and feed rate) on medical-grade PMMA. A single objective analysis conducted showed that the optimal material removal rate (MRR) occurs at a spindle speed of 1250 rpm, a depth of cut of 1.2 mm, and a feed rate of 350 mm/min. The ANOVA showed that feed rate is the most significant factor towards the MRR, and spindle speed (11.83%) is the least contributing. The optimal surface roughness (Ra) occurred at spindle speed of 500 rpm, depth of cut of 1.2 mm, and feed rate of 200 mm/min. The milling factors were insignificant. A regression analysis for prediction was also conducted. Further, a multi-objective optimization was conducted using the Grey Relational Analysis. It showed that the best trade-off between the MRR and the Ra could be obtained from a combination of 1250 rpm (spindle speed), 1.2 mm (depth of cut), and 350 mm/min (feed rate). The depth of cut was the largest contributor towards the grey relational grade (54.48%), followed by the feed rate (10.36%), and finally, the spindle speed (4.28%).

A Novel Color Recognition Model for Improvement on Color Differences in Products via Grey Relational Grade

ED light, a green energy-saving light source, can cause color cast. For this reason, LED light is seldom favored by designers. The purpose of the paper is to provide shoppers who are observing product colors in an LED-lighted setting with an innovative color identification model. Based on designers’ product color comparison, the paper employs high-reliability mechanic visual perception in combination with grey relational grade. Grey relational grade is applied to eliminate electrical fault pertaining to mechanic visual perception, whereby appropriate LED parameters and color cast inclination can be obtained. The paper first mimics retail store display windows. The color temperature and illuminance of LED light sources are adjustable. Two degrees of illuminance, including high illuminance (1500 lux) and low illuminance (500 lux), and two light source color temperatures, including yellow light (2700 K) and white light (4000 K), were assigned for study. Four colors, including red, yellow, blue and green of the natural color system, were selected as product colors. The mechanic visual perception sensor was used to identify the object (product) color, which is then converted into an RGB color model to serve as research data of color cast measurement, and the grey relational grade was applied to obtain the most appropriate LED light parameters and the color cast of the four colors. The data analysis reveals that green shows the least color cast when it is lighted by a yellow LED light source with low illuminance, yellow and blue have the least color cast when it is lighted by a white LED light source with high illuminance and red displays the least color cast when it is lighted by a white LED light source with low-illuminance. The analysis also indicates each color’s cast inclination in blackness, chromaticness and hue. As a result, LED light that is more acceptable to designers is suggested for display windows, thus reducing problems with product color cast.

Optimization of Laser Parameters and Dimple Geometry Using PCA-Coupled GRG

Stainless steel (SS316L) is applied in numerous fields due to its intrinsic properties. In this study, micro-dimples were fabricated on SS316L. The effects of laser process parameters, such as frequency, average power, and pulse duration, on the average dimple diameter, dimple distance, and dimple depth were studied using an L9 orthogonal array. The analysis of variance (ANOVA) and multi-objective optimization technique, principal-component-analysis-coupled grey relational grade (GRG), was used to optimize laser process parameters on output responses. The optimal machining parameter settings obtained for the highest GRG peak value of 0.2642 are 15 kHz (frequency), 12 W (average power), and 1500 ns (pulse duration). The ANOVA results showed that average power is the most influential factor, contributing 86.40 % to performance measures (average dimple diameter (φ), dimple distance (d), and depth (l). Moreover, the effect of process parameters was studied using mean effect plots, and the micro-dimple quality was analysed using SEM micrographs.

Correlation between experimental and analytic approaches to study the erosion rate of aluminum-metal matrix composites

The incorporation of a ceramic particles like SiC, Al2O3, and TiO2 into aluminum matrices results in Aluminum composite better mechanical and physical properties that make them attractive for various applications such as Aircraft, Helicopter, High-speed automobile, and Submarine. In this study, the erosion properties of the aluminum composite were studied in dry conditions using sand blast-erosion test rig. Impact velocity, standoff distance, particle size, particulate (wt. %), and impingement angle were preferred as control factors. Taguchi method, Grey relational and regression analysis were considered for optimizing the erosion process parameters. L27 orthogonal array was determined for the experimental trials. The most significant factors in the process were identified. Nonlinear regression model has been developed for Grey Relational Grade in relation to the different erosion parameters. An optimization schema is established based on a correlation between analytic and experimental results.

Excavating Future Challenges: An Analysis of Health Systems of One Hundred-Six Countries

Purpose: Health system of a country is backbone of economy. It has fundamental importance in sustainable development of a country. Aim of this article is to excavate future challenges to health system of selected 106 countries. Design/Methodology/Approach: It is a country level comparative analysis of health risk factors. Design of the study includes review of literature, data extraction and analysis. The cross-sectional secondary data has been drawn from website of World Development Indicators (WDI) 2020. Grey relational analysis is used as technique of investigation. Findings: Results show that majorly, member countries of Organization for Economic Co-operation and Development (OECD) have exceptionally high grey relational grade, therefore, are considered to be countries having less future health risks, whereas, Southern African Development Community (SADC) have exceptionally low grey relational grade, therefore, have high future health risk. Implications/Originality/Value: It is a unique study using different dataset and methods that provides valuable insights to political governments, researchers and health system managers.

Multiple Response Optimization of machining parameters on turning of AA 6063 T6 aluminum alloy which established on Taguchi L9 orthogonal array coupled with Grey relational analysis

With numerous responses established on Taguchi L9, orthogonal array coupled with current work proposes a novel methodology for optimizing machining parameters on turning of AA 6063 T6 aluminum alloy. Experimental assessments are accomplished on AA 6063 T6 aluminum alloy. Turning trails are carried out under dry cutting conditions using an uncoated carbide insert. Cutting parameters such as cutting speed, feed rate, and depth of cut are optimized in this effort while numerous responses such as surface roughness(Ra) and material removal rate are taken into consideration (MRR). From the grey analysis, a grey relational grade(GRG) is calculated. The optimal amounts of parameters have been identified based on the values of grey relational grade, and then ANOVA is used to determine the significant influence of parameters. To authenticate the test result, a confirmation test is executed. The result of the experiments shows that by using this method. the turning process responses can be significantly improved.

Influence of Tool Nose Radius and Cutting Performance during Face Milling of Magnesium Alloy for Output Responses by Taguchi based Grey Relation Analysis

In order to take advantage of the machining characteristics of magnesium, it is useful to consider recommended tool design and angles. The geometry of the tool can have a large influence on the machining process. Tool geometry can be used to aid with chip flow and clearance, reduce excessive heat generation, reduce tool build up, enable greater feed rates to be employed and improved tool life. This paper presents a new approach for the optimization of machining parameters on face milling of ZE41 with multiple responses based on orthogonal array with grey relational analysis. Machining tests are carried out by inserting 12 mm diameter of insert having 1 flute under dry condition. In this study, machining parameters namely cutting speed, feed and depth of cut and tool node radius are optimized with the considerations of multi responses such as surface roughness, material removal rate, tool wear and thrust force. A grey relational grade is obtained from the grey analysis. Based on the grey relational grade, optimum levels of parameters have been identified and significant contribution of parameters is determined by ANOVA. Confirmation test is conducted to validate the test result. Experimental results have shown that the responses in Machining process can be improved effectively through the new approach.

A Country-Level Analysis of Worldwide Official Financing by International Financial Institutions

This study aims to evaluate worldwide official financial flows by international financial institutions to selected 123 countries of the world. The design of the study is composed of a review of literature elicited from research databases, extraction of secondary data of World Development Indicators (WDI) 2020, and mathematical analysis. In real time, cross-sectional country-level data, a classical process of Grey Relational Analysis (GRA) has been applied. Results of the study show that Argentina, Ethiopia, Bangladesh, India, Egypt, Arab Rep., Kenya, Costa Rica, Vietnam, Chad, Tanzania, Colombia, Uzbekistan, Nepal, Indonesia, Nigeria, Rwanda, Cameroon, and Uganda have exceptionally high grey relational grade meaning thereby, having an effective system of obtaining official international financial flows. Zimbabwe, Russian Federation, Botswana, Afghanistan, Bulgaria, South Africa, Burundi, Belarus, Kazakhstan, Armenia, Pakistan, Peru, Romania, and Ukraine have poor grey relational grade meaning thereby, having a relatively weak system of obtaining official financial flows. It is a unique study that provides extensive information on the official financial flows of more than a hundred countries of the world and provides the basis for the informed opinion of policymakers, political governments, economic policymakers, researchers, and academia. It also provides valuable information useful for international financial institutions.

Wear Resistivity of Al7075/6wt.%Sic Composite by using Grey-Fuzzy Optimization Technique

Application of SiC particulate reinforcement impact greatly for making aluminium matrix composite because of its superb heat conductivity, oxidation stability and highly resistance to mechanical erosion. Present work based on dry sliding wear analysis of Al7075/6wt.%SiC composite fabricated by liquid state stir casting method. To acquire a productive wear rate, three major process parameters viz. load, sliding speed and covering sliding distance were compared four different levels. ANOVA analysis showed that the probability rate of load is less than 0.05 that revealed their significant factor. From the study, the highest GRG and GFG values are found 0.914 and 0.854 respectively for the optimal operating parameters of 10 Newton load, 2 metre/second sliding speed and 500 metre sliding distance. Finally, it is revealed that the grey-fuzzy technique effectively authenticate the decision making of wear performance characteristics rather than a plain grey relational grade.

Taguchi Grey Relational Analysis on the Mechanical Properties of Natural Hydroxyapatite: Effect of Sintering Parameters

Our previous study have reported synthesis and mechanical properties of natural hydroxyapatite (HA), but optimization of the measured hardness and compressive strength has not been examined. This paper presents optimization of mechanical characteristics (hardness and compressive strength), using Taguchi-grey relational analysis design. In the design, three factors with mixed levels (2 and 3) is employed with the consideration of sintering parameters (0 and 500 Pa compaction pressure, and 900, 1000 and 1100 oC sintering temperature), reported in the previous study. The orthogonal array L18 having 18 rows corresponding to the number of tests and the required columns was selected. Results obtained shows that HA with good hardness and compressive strength is feasible with less or no compaction pressure sintering parameter. An optimum grey relational grade (GRG) of the synthesized HA is 0.7171 and has experimental value within 95% confidence interval.The optimal sintering parameters are gotten to be 500Pa compaction pressure and 1100 oC sintering temperature. Result shows that sintering temperature having 99.90 percentage of contribution is the most significant factor, while compaction pressure and error are insignificant on the overall hardness and compressive strength of the synthesized HA.