Gears are among the most crucial components in the transmission systems of machine tools. Gear manufacturing includes a number of processing procedures. The grinding process is an important procedure ...involving high precision and fairly small grinding surfaces. For this reason, this study aimed at developing a quality assessment model for the internal cylindrical grinding process of gears. The Six Sigma quality indices (SSQIs) were used to directly assess the quality of the internal cylindrical grinding process due to their ability to directly reflect quality level and process yield. Since the process may include nominal-the-best (NTB), larger-the-better (LTB) and smaller-the-better (STB) quality characteristics, so we used the variable transformation method to normalise the specifications of each quality characteristic for the convenient and effective management and analysis of process performance for multiple quality characteristics. We then constructed a multi-characteristic process quality analysis chart (MPQAC) to simultaneously assess the quality levels of various quality characteristics. Furthermore, the MPQAC can provide references for process improvement. This ensures the quality of internal cylindrical grinding and enhances the quality of gear and machine tool products. Finally, a real-world application and numerical experiments demonstrate the effectiveness and practical applicability of the proposed method.
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BFBNIB, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Quality in education represents a predictor of education for sustainability development. This article aims to measure: (a) the level of satisfaction perceived by students regarding the development of ...the didactic communication process (OS1) (b) the assessment of the importance given by the student to the organizational and didactic practices necessary to increase the quality of university education (OS2). The research is quantitative, and its specific tools were designed considering the following variables: (a) dependent variables: satisfaction, and knowledge, and (b) independent variables: indicators of effective communication quality, teacher competencies, effective learning practices, quality of training, importance and performance in training professional and transversal skills, indicators of conflict of interest and ethical dilemmas. The data processing aimed at determining the average scores for each dimension investigated and their ranking was based on the values obtained for each provided subsample. The resulting values have an average score of 1.45 and 1.34, respectively, revealing a relatively small distance between those two dimensions. This leads us to appreciate that students know the role, place and importance of the learning environment in increasing academic performance. Providing support services for students is also perceived as important since the average score obtained is 1.23 - not far from the average of those related to the learning environment. Didactic communication contributes to the efficiency of the didactic process; it is appreciated that empathy, personal integrity and expressiveness are the attributes that any teacher must possess; compliance with the rules can be considered a pillar of academic quality and academic success. At the ranking level, those dimensions rank first in importance, followed by “learning autonomy” (second place), ensuring an adequate learning environment (third place) and providing support services for students (fourth place).
•We conducted meta-analysis of preschool professional development (PD) research.•Outcomes for educators: process quality, structural quality, and knowledge.•Outcomes for children: receptive ...vocabulary, phonological awareness, and letter knowledge.•PD yielded gains for process and structural quality in educators.•PD yielded gains for phonological awareness and letter knowledge in children.
Professional development (PD) is increasingly used to improve early childhood educators’ skills and knowledge in providing quality language and emergent literacy environments for children. However, the literature does not clearly indicate the extent to which such efforts reach their goals, or whether improvements in educator outcomes translate to learning gains for children. In the current synthesis, we conducted meta-analyses to evaluate the effects of language- and literacy-focused PD on process quality, structural quality, and educator knowledge as primary outcomes. Furthermore, we estimated effects for three child outcomes: receptive vocabulary, phonological awareness, and alphabet knowledge. PD produced a medium effect for process quality and a large effect for structural quality but no effect for educator knowledge. PD also produced a small to medium effect for phonological awareness and a small effect for alphabet knowledge, but these were not predicted by gains in educator outcomes. Although course and coaching intensity and duration were related to effect sizes, the total number of PD components was the strongest predictor of process quality. The results suggested that PD is a viable method of improving language and literacy processes and structures in preschools, but effects may need to be substantial if they are to translate into higher child outcomes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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•Propose an evaluation index for the distillation process with multiple factors.•Propose three total distillation schemes for separating DMA/HAc/water.•Three heat integrated ...configurations further improve energy efficiency.
Industrial wastewater containing N,N-Dimethylacetamide (DMA) and acetic acid (HAC) will be produced in the production of DMA by acetic acid method. The binary mixture of HAc and DMA has maximum-boiling azeotropic point, and the relative volatility of HAc and water is small. Therefore, high purity separation cannot be realized by traditional distillation. By analyzing the separation methods of binary mixture, three processes of extractive-pressure swing distillation, azeotropic-pressure swing distillation, and azeotropic-extractive distillation are proposed to separate DMA-HAc-water ternary mixtures. The heat integration enhancement configuration is completed according to the process characteristics. The results show that compared with the conventional processes, the TAC of the three heat integration processes is reduced by more than 25%, and the energy consumption is reduced by more than 40%. The process quality index (PQI), which integrates TAC, energy consumption, environment and thermodynamic efficiency, is proposed and applied to the evaluation of all processes. The results indicate that the heat integrated azeotropic-extractive distillation (HIAED) process shows more significant industrial application potential.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A novel asymptotic optimization strategy is proposed to adjust the operational conditions iteratively based on the Bayesian optimization method.•The specified quality target is incorporated into the ...GP framework and EI acquisition function to improve the convergence property.•The improved EI is further combined with BOBYQA to accelerate the convergence, and an efficient warm start rule is developed when switching from BO to BOBYQA.•The comparison results in case studies show that the proposed quality control method can efficiently achieve the specified quality target.
How to take as few experiments as possible to achieve the desired quality target is a challenging and essential topic of process quality control, especially for complex and expensive manufacturing processes with high-dimensional quality outputs. This paper proposes a Bayesian optimization (BO)-based strategy utilizing quality information with adaptive local convergence. First, a series of pretreatment setting rules of the Gaussian process model is proposed to reduce the uncertainty of BO. Then, the quality target is adopted into the Gaussian process model, and the acquisition function is improved. Finally, to balance global exploration and local exploitation and reduce the experimental cost, an adaptive criterion is designed to switch global BO search to local search. The operating conditions can be efficiently updated until the quality target is reached. Two applications with high-dimensional quality outputs are presented to demonstrate the effectiveness of the proposed method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study investigates the degree of concordance between fifteen measures of audit quality used in academia and two measures of audit process quality determined either by audit firms’ internal ...inspections or by Public Company Accounting Oversight Board inspections of individual engagements. Using two confidential datasets of these assessments of audit process quality, I find that three of the measures of audit quality used by academics have significant associations with both measures of audit process deficiencies used by auditors and regulators: (i) the propensity to restate financial statements, (ii) the propensity to meet or beat the zero earnings threshold, and (iii) audit fees. Seven academic proxies are significantly associated with only one audit process quality measure, and five have insignificant associations with both practitioner assessments. Overall, the significant associations indicate that practitioners and academics share common ground in identifying low-quality audits. These findings can provide guidance for future studies in selecting audit-quality proxies suitable for different research questions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The purpose of this paper is to empirically examine a theoretical model which identifies the effect of process quality improvement and lean practices on competitive performance in the healthcare ...industry in the United Arab Emirates (UAE). The study uses a quantitative research technique with convenient cluster sampling through applying a descriptive, causal and analytical research design. A valid sample size of 270 respondents is used for analysis by linear regression and hypothesis testing using SPSS. The results indicate a direct significant relationship between process quality improvement and a direct significant relationship between lean practices and competitive performance. Given the substantial resources spent and efforts to improve healthcare quality, the absence of studies demonstrating the impact of quality-related operations and activities would require future research. Hospitals in one city in UAE have access that limits the research results. It is recommended that future research assess more variables dependency on the healthcare sector that can affect increase competitiveness. The research provides some managerial implications that could help hospital managerial members improve their healthcare delivery system's leanness and quality improvement to get competitiveness. Quality improvement and lean practices help increase competitive performance and can assist the healthcare sector in providing better service using these practices that have never been considered in research.
Widespread uptake of Carbon Fiber Reinforced Plastics (CFRP) in the aerospace and automotive industries over the past two decades has highlighted the importance of machining composites in large ...production environments. The abrasive nature of carbon fibers and inherently heterogeneous structure of CFRP laminates create tool wear conditions that are unlike those typical of metal machining. The present work quantifies thrust force, tool flank wear and push-out delamination (POD) for drilling of 8 mm thick CFRP laminates with 8 mm high-speed steel drill bits. Thrust force, directly responsible for delamination effects, is found to increase with feed rate and cutting speed, while flank wear increases at lower feed rate and higher cutting speed. POD is found to increase with feed rate and tool wear, with excessive values of the latter found to change the material removal mechanism from cutting to tearing of fibers resulting in increases in local workpiece temperature and matrix degradation. A quality monitoring and control strategy for drilling of CFRP laminates is then proposed based on these observations by exploiting a fuzzy logic algorithm to predict POD based on thrust force and flank wear measurements. Feed rate, in turn, is controlled based on the POD to ensure acceptable machining quality over the entire lifespan of the tool. The developed approach offers an effective and simple way of maximizing throughput and tool duration while guaranteeing part quality.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Group size and children-to-teacher ratio do not predict process quality.•Teacher formal education weakly predicts process quality.•Use of an education program predicts process quality with a medium ...effect size.•Professional development activities strongly predict process quality.
The relationship between structural quality and process quality in early childhood education and care (ECEC) has been addressed in several studies. However, the findings are not conclusive. The present study was conducted in the Netherlands, which has a strongly regulated mid-quality ECEC system regarding structural aspects, with still considerable variation in process quality. The study employed a multi-method approach and extended the existing research in two ways. First, both observations of teacher–child interactions as well as teacher-reported developmental and educational activities were included as indicators of comprehensive emotional and educational process quality constructs. Second, to examine the relation between process quality and structural quality, commonly studied structural quality characteristics were complemented by less frequently studied measures of the professional development activities and education programs implemented at the centers. Results indicate that group size and child-to-teacher ratio are not related to emotional and educational process quality in the Dutch ECEC system. Teachers’ formal pre-service education has a positive, but small association with emotional process quality. The use of an education program and professional development activities at the center show the strongest associations with emotional and educational process quality. Implications for policy and practice are discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Self-piercing riveting (SPR) process has been widely applied in different industrial fields to join similar or dissimilar materials. This paper aims to investigate the SPR joinability of ...aluminium–steelhybrid sheets and obtain the design range of material strength and thickness distribution. A 2D axisymmetric numerical model is constructed based on r-adaptivity method to simulate the SPR process. The accuracy of the numerical model is validated by comparing the cross-sectional shape of SPR joint between test and simulation Parametric study is performed to explore the effects of material strength and sheet thickness on the SPR joinability and process quality indexes. The results show that (i) SPR joinability of aluminium–steel hybrid sheets can be improved by setting the softer and thicker sheet as the lower sheet when the flow stress of upper sheet is equal from 183MPa to 517MPa; (ii) Undercut decreases with an increase of sheet flow stress ratio, while the opposite trend is observed for minimum thickness. Undercut and minimum thickness decrease with an increase of sheet thickness ratio. (iii) a qualified SPR joint with good connection strength can be obtained when sheet flow stress ratio is equal from 0.27 to 1.84 and sheet thickness ratio is equal from 0.77 to 1.78. This study provides an available reference for determining the material strength and thickness distribution in the application of SPR of aluminium–steel hybrid sheets.
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•A numerical model of SPR of aluminium-steel hybrid sheets process is constructed.•SPR joinability is improved by setting thicker sheet softer sheet as lower sheet.•A qualified SPR joint with good connection strength is obtained.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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