scholarly journals Reduction of Cracks in Marble Appeared at Hydro-Abrasive Jet Cutting Using Taguchi Method

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 486
Author(s):  
Sorin Barabas ◽  
Adriana Florescu

The appearance of cracks in brittle materials in general and in marble, in particular, is a problem in the hydro-abrasive jet cutting process. In this paper is presented a method to reduce the appearance of cracks when cutting with a hydro-abrasive jet of marble by using statistical analysis. The Taguchi method was used, establishing the main parameters that influence the process. Research design was based on performing experiments by modifying the parameters that influence the process. In this way, it has been shown that the stochastic effects resulting from the marble structure can be reduced. A careful study was made of the behavior of marble under the action of the hydro-abrasive jet, and of the behavior of the whole process in the processing of brittle materials. Results of experiments confirmed the hypothesis that statistical analysis is a procedure that can lead to a decrease in the number of cracks in processing. The measurement was performed with precise instruments and analyzed with recognized software and according to the results obtained, the reduction of the number of cracks is achieved through use of low pressure, a minimum stand-off distance and a small tube diameter. In this way, the paper presents a new and effective tool for optimizing the cutting with a hydro-abrasive jet of marble.

2001 ◽  
Vol 6 (3) ◽  
pp. 187-193 ◽  
Author(s):  
John R. Nesselroade

A focus on the study of development and other kinds of changes in the whole individual has been one of the hallmarks of research by Magnusson and his colleagues. A number of different approaches emphasize this individual focus in their respective ways. This presentation focuses on intraindividual variability stemming from Cattell's P-technique factor analytic proposals, making several refinements to make it more tractable from a research design standpoint and more appropriate from a statistical analysis perspective. The associated methods make it possible to study intraindividual variability both within and between individuals. An empirical example is used to illustrate the procedure.


Author(s):  
Muataz Al Hazza ◽  
Khadijah Muhammad

High speed machining has many advantages in reducing time to the market by increasing the material removal rate. However, final surface quality is one of the main challenges for manufacturers in high speed machining due to the increasing of flank wear rate. In high speed machining, the cutting zone is under high pressure associated with high temperature that lead to increasing of the flank wear rate in which affect the final quality of the machined surface. Therefore, one of the main concerns to the manufacturer is to predict the flank wear to estimate and predict the surface roughness as one of the main outputs of the machining processes. The aim of this study is to determine experimentally the optimum cutting parameters: depth of cut, cutting speed (Vc) and feed rate (f) that maintaining low flank wear (Vb). Taguchi method has been applied in this experiment. The Taguchi method has been universally used in engineering analysis.  JMP statistical analysis software is used to analyse statically the development of flank wear rate during high speed milling of hardened steel AISI D2 to 60 HRD. The experiment was conducted in the following boundaries: cutting speed 200-400 m/min, feed rate of 0.01-0.05 mm/tooth and depth of cut of 0.1-0.2 mm. Analysis of variance ANOVA was conducted as one of important tool for statistical analysis. The result showed that cutting speed is the most influential input factors with 70.04% contribution on flank wear.


2010 ◽  
Vol 3 (2) ◽  
pp. 96-97
Author(s):  
Lindsey E. Eberman ◽  
Kimberly J. Bodey ◽  
Rebecca Zakrajsek ◽  
Madeline McGuire ◽  
Adam Simpson

Background:The National Standards for Sport Coaches (2006) acknowledges that differences exist in athletes’ ability to tolerate heat. As such, Domain 2: Safety and Injury Prevention (S7-10), Domain 3: Physical Conditioning (S12-13), and Domain 7: Organization and Administration (S34) list expectations for coaches’ ability to recognize and respond to heat illness. However, only the American Red Cross of Greater Indianapolis (Domain 2 specific) and 13 programs are accredited by NCACE. Moreover, on-line trainings frequently used to educate novice interscholastic and recreational sport coaches provide only a cursory review of heat illness precautions, symptoms, and remedies.Objective:The purpose of this exploratory study is to identify changes in coaches’ actual and perceived knowledge after an on-line educational intervention, as well as determine whether the educational intervention will decrease the knowledge gap.Research Design:A pre-test/post-test design was used to identify the effect of an educational intervention on perceived and actual knowledge of sport coaches.Participants:Coaches (n=19; male=14, female=5) were solicited via email made available by the Indiana High School Athletic Association and the Indiana Youth Soccer Association – Olympic Development Program.Instrumentation:The Perceived Knowledge Questionnaire (five-item survey) and an actual knowledge assessment (two versions of 19-item quiz) were used to measure the coaches’ perceived and actual knowledge about the prevention, recognition, and treatment of exertional heat illnesses. Participants completed the “Beat the Heat: Be a Better Coach in Extreme Environmental Conditions” educational intervention.Procedures:Coaches completed the on-line educational module including pre-test and post-tests evaluations of actual and perceived knowledge.Statistical Analysis:Researchers performed three separate paired t-tests to identify the effect of the educational intervention on the dependent variables: actual knowledge, perceived knowledge, and knowledge gap. Significance was set a-prior at p<0.05.Results:Participants demonstrated a significant 18.1% improvement (t18=-4.877, p<0.001, ES=0.62) in actual knowledge scores. Perceived knowledge also significantly improved (t18=-2.585, p=0.019, ES=0.25). Knowledge gap, the difference between actual knowledge and perceived knowledge, became significantly smaller (t18=4.850, p<0.001, ES=0.63).Conclusions:Results indicate the on-line educational intervention improved actual knowledge, perceived knowledge, and decreased the knowledge gap. Additional large scale study of this intervention is warranted.


2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Endang Mahpudin Made Panji Syamsul

The implementation of good governance is a prerequisite condition for every government to achieve people's aspirations. Every work unit is determined to reach agency accountability as the consequence of the mandate/responsibility it carries. This is done through considering the resources it manages in order to make government and development run effectively and efficiently, clean and responsibly.� The research aims to find out and analyze the influence of performance-based budgeting performance on the accountability of government agencies within Karawang Regency. This research uses descriptive quantitative method in the form of statistical analysis, where the data is sourced from primary and secondary data coming from local government of Karawang Regency or other institutions related to this research. Descriptive method is a method that describes and presents an object as it is. Quantitative analysis in research design is intended to know the influence between independent variables with dependent variable. Based on the results of analysis and discussion, a conclusion can be drawn, that the implementation of performance-based budgeting affects the accountability of local government agencies within Karawang Regency. Improved implementation of performance-based budgeting will be followed by increased accountability of local government agencies. �Keywords:� Performance-based Budgeting, Accountability, Local Government


2019 ◽  
Vol 2 ◽  
pp. 25-31
Author(s):  
REENA BAJPAI ◽  
CHANDRA P. KHOKHAR

The life situations are always changing. Everyone is unique and our philosophies of life, abilities and attitudes are totally different from others. Adjustment is essential for successful life and it is a lifelong process, which never ends. The aim of the study was designed to study the effect of Sankeertan on level of adjustment of adolescent girls. Forty adolescent girls of 16 to 19 years were taken through accidental sampling. Quasi experimental research design was applied for this research and t-test was used for statistical analysis. Obtained result was significant at 0.01 level of confidence. It concludes that Sankeertan plays a vital role in improving the adjustment level of the adolescent girls. 


2020 ◽  
Author(s):  
Jan Walleczek ◽  
Von Stillfried

A general commentary by Walleczek and von Stillfried (2020) was recently published in Frontiers in Psychology. The present work provides an account of (i) the detailed research record and (ii) the main arguments behind the commentary for the purpose of full transparency and disclosure. For historical overview, Walleczek and von Stillfried (2019) had previously reported (i) the absence of any true-positive effects and (ii) the presence of one false-positive effect in a commissioned replication study of the Radin double-slit (DS) experiment on observer consciousness. In their subsequent misrepresentations, Radin et al. (2019, 2020) regrettably used the malpractice of undisclosed HARKing, i.e., undisclosed hypothesizing after the results are known. HARKing can increase greatly the risk of false-negative or false-positive conclusions. Specifically, Radin et al. (2019, 2020) deviated in two major ways from the pre-specified protocol for this commissioned study, which (i) was agreed to by Radin before data collection was started (Radin, 2011) and (ii) included data encryption to prevent the use of p-hacking and HARKing. First, Radin et al. (2019) violate the original research design by reporting a so-called “true-positive outcome of a secondary planned hypothesis”. Contrary to the claim by Radin et al. (2019, 2020), that hypothesis was not, however, part of the planned test strategy, but, instead, the associated statistical analysis – a chi-square test – was chosen by Radin sometime after the planned statistical analysis had been completed and the data unblinded. Second, Radin et al. (2019, 2020) violate the funder-approved research design in an additional way by falsely claiming that the newly developed protocol, i.e., the advanced meta-experimental protocol (AMP), implements a non-predictive test strategy when – in fact – the AMP-based test strategy is strictly predictive. Put simply, Radin et al. (2019, 2020) are mistaken that the funder-approved hypotheses posited the random occurrence of effects for the test categories in this replication experiment; instead, a different specific prediction was tested in each of the eight planned test categories, and true-positive effects were predicted to occur for only two (12.5%) of the 16 possible measurement outcomes of the eight planned single-test categories. Therefore, in the predictive single-testing regime, a statistical correction for non-predictive, i.e., random, multiple testing would not be appropriate and would thus violate the AMP-based strategy, which was implemented in the commissioned study based upon the planned outcome predictions as pre-specified in Radin (2011). Neither of these post-hoc changes by Radin et al. (on the basis of HARKing) were disclosed in Radin et al. (2019, 2020) and both these changes violate the funder-approved, original methodology agreed upon in Radin (2011) and pre-specified in the research contract. In summary, the present work reconfirms that – exactly as reported in Walleczek and von Stillfried (2019) – “the false-positive effect, which would be indistinguishable from the predicted true-positive effect, was significant at p = 0.021 (σ = −2.02; N = 1,250 test trials)” and “no statistically significant effects could be identified” in those two groups for which true-positives were predicted to occur. These observations are consistent also with an independent statistical reanalysis of the Radin DS-experiment by Tremblay (2019) and a replication attempt by Guerrer (2019). Tremblay reported significant false-positives in control groups and Guerrer found significant effects with post-hoc analyses only, but null results only when using the planned confirmatory analysis. As a general recommendation, the authors call for the implementation of advanced control-test strategies, including novel approaches from the metascience reform movement, for empirically detecting and preventing uncontrolled false-positive effects in parapsychological research.


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