Modeling the abrasive wear behavior of in-situ synthesized magnesium RZ5/TiB2 metal matrix composites

In the present study, the statistical analysis on tribological behavior of RZ5/TiB2 magnesium-based metal matrix composites is carried out using Taguchi design and analysis of variance (ANOVA) technique. Taguchi analysis using signal-to-noise ratio indicates that the sliding distance and wt.% TiB2 are the most significant factors in evaluating weight loss and coefficient of friction, respectively. The regression equation is formulated utilizing the ANOVA technique to study the output responses based on the input abrasive wear test experimental results. The regression equation is validated through a comprehensive study taking a series of abrasive wear tests and indicates the percentage deviation of regression modeling is in the range of ± 10%. The individual and combined effect of wear parameters on tribological behavior are investigated through the main effect plots and response surface plots. The micrograph of the worn surface of RZ5/TiB2 composites is studied using field emission scanning electron microscope (FESEM), indicating the formation of an oxide layer on the worn surface.

Parameters of Porosity and Compressive Strength-Based Optimization on Reinforced Aluminium from the Recycled Waste Automobile Frames

Automobile industries were ready to recycle the waste old parts as well as the damaged parts of the old vehicles as much as possible. This study mainly focused on the recycling of the waste and damaged aluminium frames of the automobile bodies. These aluminium-based frames only collected the metal matrix composite created by reinforcement of 3% silicon carbide (SiC) and 3% high carbon steel. The stir casting method is chosen to make the composites. Optimization is done by Taguchi ANOVA technique. Three input parameters such as stir speed, time of squeeze, and the temperature of the preheating were considered. The outputs such as compressive strength and porosity were experimentally measured with the combination of nine (L9) experimental trails. The measured experimental results were analyzed and optimized with the help of Taguchi technique with different plots for clear identification. The optimized parameters based on low porosity and high compressive strength were recommended for conclusion.

THE IMPLEMENTATION OF USING QUIZIZZ AND G-FORM DURING THE COVID-19 PANDEMIC BASED ON STUDENTS’ ATTITUDE

This study aims to evaluate the effectiveness of Quizizz and G-Form media based on students' attitudes in learning mathematics. This study used an experimental method with a two-way analysis of variance (ANOVA) technique and Tukey's test. The population is SMAN 3 Sidoarjo grade XI aged 15-17 years as many as 130 students, while the sample is 64 students. Data collection was carried out using test and questionnaire techniques. The results showed that: (a) the mathematics learning outcomes of students who used the G-Form media were higher than those taught using the Quizizz media, (b) there is an interaction between learning media and learning attitudes towards students' mathematics learning outcomes, (c) for students who have positive learning attitudes, there is no significant difference in mathematics learning outcomes of students using G-Form and Quizizz media, and (d) for students who have negative learning attitudes, there are differences in the mathematics learning outcomes of students taught by the G-Form and Quizizz media. We suggest exploring deeper into this media using material that is more authentic to students.

Study of the Surface and Dimensional Quality of the AlSi10Mg Thin-Wall Components Manufactured by Selective Laser Melting

Additive manufacturing (AM), a 3D printing technique that manufactures components by sequential addition of powder, has massively reshaped the manufacturing and engineering sectors from batch production to manufacturing customized, innovative, state-of-the-art, and sustainable products. Additive manufacturing of aluminum alloys by selective laser melting (SLM) is one of the latest research trends in this field due to the fact of its advantages and vast applications in manufacturing industries such as automobiles and aerospace. This paper investigated the surface and dimensional quality of SLM-built AlSi10Mg parts using a response surface method (RSM) and found the influence of the wall thickness and process parameters (i.e., laser power, scanning speed, hatch distance) on the pieces. Thin-walled test specimens of AlSi10Mg alloy were manufactured with different combinations of process parameters at three wall thicknesses: 1.0 mm, 2.0 mm, and 3.0 mm. The Minitab DOE module was used to create 27 different configurations of wall thickness and process parameters. The samples’ surface roughness and dimensional accuracy were investigated, and the findings were evaluated using the ANOVA technique. The regression model and the ANOVA technique showed high precision and had a particular reference value for practical engineering applications.

Electrochemical Degradation of DSW Using Fe- Fe and Al- Al Electrodes Taguchi and Anova Approach

Expulsion of toxins from distillery spent wash (DSW) was applied by utilizing a blend of matched aluminum and iron electrodes in a clump method of activity utilizing electrochemical procedure. The refinery spent wash was described diagnostically utilizing standard strategy for examination and the treatment results were dissected as far as COD and Colour. The examinations were directed to consider the impact of working boundaries, for example, voltage, separation between the electrodes and electrolysis time and were optimized by utilizing Taguchi and ANOVA technique. pH and stirring speed were kept constant as 7 and 500 rpm. The most extreme expulsion efficiencies of COD and Colour were monitored by considering total of 16 experiments each with three trials. The Taguchi method led to COD of 95% and color removal of 94%, optimized with Al-Al electrodes at the voltage of 25V, distance of electrodes 2 cm and the electrolysis time of 150 minutes. The most extreme COD and Colour removal efficiencies found to be 92% and 89% from Fe-Fe electrodes at the indistinguishable working conditions. In any case, the aluminum electrodes seen progressively appropriate for the deprivation of DSW when contrasted with iron electrodes.

Does Reward Affect the Accuracy of Pupil Perception?

<p style="text-align: justify;">Accuracy of perception is the ability of individuals to recognize, organize, and interpret input from the environment and it is influenced by the level of individuals’ concentration on observing an object. When we can find out the causes of individual perceptual accuracy, we can design a learning instrument to enhance this ability. The purpose of this study is to examine the effect of r`eward on the accuracy of pupils' perceptions. The study employs a comparative experimental approach, in which 20 subjects are divided into two groups: 10 subjects were promised rewards and 10 subjects were not. The accuracy of perception is measured by the length of time used by subjects when completing two different levels of tests. The more time required by subjects to complete the test, the more inaccurate perceptions of research subjects. To test hypotheses, the researcher performed the Split-Plot Anova technique on the subject's length of time completing the tests. The result shows that the p-value is 0.115, greater than 0.05 which means that there was no influence of giving rewards on the accuracy of perception.</p><p style="text-align: justify;"><em>Kecermatan persepsi merupakan kemampuan individu dalam mengenali, mengorganisasikan, serta memaknai hal-hal yang berada di lingkungan sekitar dan dipengaruhi oleh tingkat konsentrasi individu dalam mengamati suatu objek. </em><em>Ketika kita dapat mengetahui penyebab kecermatan persepsi yang dimiliki individu, kita dapat merancang sebuah instrumen pembelajaran untuk meningkatkan kemampuan ini.</em><em> Oleh karena itu penelitian ini bertujuan untuk menguji pengaruh pemberian </em><em>penghargaan </em><em>terhadap kecermatan persepsi peserta didik. Penelitian yang menggunakan kaidah kuantitatif dengan pendekatan eksperimen komparasi ini membagi 20 subyek ke dalam dua kelompok yaitu 10 subyek yang dijanjikan reward dan 10 subyek tidak dijanjikan reward. </em><em>K</em><em>ecermatan persepsi </em><em>subyek </em><em>diukur dengan tes </em><em>yang</em><em> diberikan sebanyak dua kali menggunakan instrumen yang berbeda dengan memperhatikan lama waktu subyek menyelesaikan tes. Semakin banyak waktu yang dibutuhkan oleh subyek</em><em> dalam menyelesaikan tes</em><em>, semakin tidak cermat persepsi subyek penelitian</em><em>.</em><em> Data rentang waktu subyek dalam mengerjakan tes dianalisis dengan teknik Split-Plot Anova. Hasil penelitian menunjukkan bahwa nilai signifikansi yang diperoleh adalah 0,115 lebih besar dari 0,05 sehingga dapat disimpulkan bahwa tidak ada pengaruh antara pemberian </em><em>penghargaan</em><em> dengan kecermatan persepsi yang dimiliki subyek</em><em>.</em></p>

EXPLORING PRE-SERVICE CHEMISTRY TEACHERS’ PROBLEM SOLVING SKILLS ON VOCATIONAL CONTEXT-BASED LEARNING

Problem-solving skill is an important component in achieving a successful 21st-century learning system. This research aimed to explore Pre-service Chemistry Teacher’ (PsCT’) problem-solving skill after CBL (Context-based learning) implementation with vocational case on petroleum and polymer topic of chemistry. A descriptive study on the CBL implementation was adopted in this research. The study focused on the exploration of PsCT’ problem-solving skill. Through convenient sampling technique, the sample covered a total of 34 PsCT (10 males and 24 females) who enrolled in vocational chemistry course were selected in this study. The data of PsCT’ problem-solving skill were collected through Rubric for Problem-solving skill (RPSS). There were four aspects of problem-solving skill used in this research, namely problems identification skills, information collection skills, skills to provide possible solution, and skills of communicating the possible solution. These data were analysed according to descriptive quantity and one-way ANOVA technique. Three open-ended questions were used to explore PsCT’s view about the relevance, usefulness, and effectiveness of the CBL implementation. There was a significant difference on PsCT’ problems solving skills among petroleum and polymer topic. The result of this study indicated that PsCT’ problem-solving skill still in sufficient category. Hence, these skills should be improved especially on the skills to analyse the problem comprehensively and make an appropriate conclusion. The PsCT have positive view toward CBL implementation about the relevance, usefulness, and effectiveness. The implementation of CBL with vocational case is promising since it could improve PsCT’ problem-solving skills.

EARNINGS ANNOUNCEMENTS AND THE SECURITY TRADE VOLUMES OF LISTED COMPANIES IN KENYA

Purpose: This study investigated the decline in the NSE N20, Kenya share index by examining the effects of Earnings announcements on the security trade volumes of companies listed on the NSE, Kenya, from 2013 to 2017. The study formulated a hypothesis that Earnings announcements did not significantly affect the security trade volumes of companies listed on the NSE, Kenya, applied Signaling theory, efficient market hypothesis, and Market expectation theory.Methodology: The study used the event study methodology, a mixed research design, and the ANOVA technique from 25 listed companies, collected secondary data using schedules and primary data using questionnaires.Findings: The study found the effect of Earnings announcements on the trade volumes to be insignificant. Hence, it concluded that earnings announcements did not affect the security trade volumes of companies listed on NSE, Kenya.Unique Contribution to Practice and Policy: The finding of this study will provide the market players with a better understanding of how Earnings announcements affect the security trade volumes; provide the policymakers with a basis of designing policies, regulating and controlling financial markets, complement existing studies in this area and strengthen the foundation for further research.

The Effect of Problem-Based Learning Model of Food Cutting Competency Toward the Student Learning Outcomes of Class X at SMK YPM 2 Taman

This study aims to: analyze the student learning outcomes using the problem-based learning model, compare to the student learning outcomes using the direct learning model. The type of this study is experimental research that is the factorial design. The study population is all of the students in class X. Therefore, the research sa DLMes are the students of Class X of Culinary Art 1 as the experimental class and the students of Class X of Culinary Art 2 as the control class. The researcher analyzed the data using the analysis of variance (ANOVA) two-way Anova after accoDLMishing the normality and homogeneity test requirement. Based on the result of hypothesis test using ANOVA technique, the researcher found that: (1) the student learning outcomes of cognitive aspects using problem-based learning model was significantly higher than the student learning outcomes using the direct learning model.

Awareness Level of Airline Pilots on Flight-Associated Venous Thromboembolism

INTRODUCTION: Studies have identified a great number of physiological conditions, including venous thromboembolism and hypoxia, that may give rise to medical disqualifications and in-flight incapacitations that can be costly to individuals and organizations. Over the past three decades, much attention has been focused on venous thromboembolism among passengers. However, studies on venous thromboembolism among commercial airline pilots are very scarce. With this consideration in mind, differently from the literature, this study set out to examine pilots' awareness of venous thromboembolism signs, symptoms, risk factors, and countermeasures.METHODS: For this purpose, a venous thromboembolism questionnaire was developed and applied to collect data. There were 427 airline pilots who participated in the questionnaire. The analysis of variance (ANOVA) technique was used to analyze the results of the questionnaire.RESULTS: According to the results of this study, approximately one-half (57.1%) of the participants had just heard of this particular health issue and 63.9% of the participants were unaware of flight-associated venous thromboembolism. Airline pilots between 20 and 40 yr of age were much less aware of venous thromboembolism in comparison to pilots 41 yr or older, and pilots flying more than 90 h/mo were at a greater risk.DISCUSSION: Airline pilots between 20 and 40 yr have less knowledge about venous thromboembolism and preventive measures against it in comparison to older pilots. Therefore they may be more vulnerable to possible risk factors. The findings of this study will contribute to increasing pilots’ awareness on flight-related venous thromboembolism and can improve the overall safety of civil aviation.Kilic B, Soran S. Awareness level of airline pilots on flight-associated venous thromboembolism. Aerosp Med Hum Perform. 2020; 91(4):343–347.