Process Related Characteristic-Based Topography Evaluation of Wear Conditions On Grinding Wheels

Non-productive auxiliary processes affect the single part and small badge production of milling tools. The key production process grinding is inevitably linked to the auxiliary conditioning process. The time demand of those process steps decreases the overall productivity of the manufacturing process. However, today the machine operator decides on conditioning cycles individually by the use of experience. Until today, there is no objective data based approach available that supports the initiation of these conditioning processes or the adaption of the grinding process itself in order to improve its process efficiency. For this purpose, a process related topography evaluation method of the grinding wheel surface is developed within this study. For the measurement an optical method based on laser triangulation is used. The measurement system is implemented into a common tool grinding machine tool. In addition, characteristic topography values are defined that show the wear conditions of the grinding tool. Moreover, the data is summarized in a database of wear conditions. The developed measurement method can save grinding and dressing tool resources, process times and minimizes scrap parts. In addition, an adaptation of the process and a targeted launch of auxiliary processes can be enabled. The novel characteristic-based topography measurement creates the opportunity to enhance the tool life of the grinding wheels up to 30 % without losing productivity.

The relative effect of student, family and school-related factors on math achievement by location of the school

This study aims to examine the relative effects of student, family and school-related characteristics on 4th grade students’ math achievement according to location of the school in Turkey. The data of 6435 students studying at 260 primary schools were analyzed using TIMSS-2015 database. The dependent variable of the study was students’ math scores and 19 factors constituting the student, family and school-related characteristics were the independent variables. The location of the school was classified as urban, suburban, medium-size city and village. The data was analyzed via single level multiple linear regression. The results revealed that the entire models explained the largest amount of variance (52%) in the schools located in the villages and the least amount of variance (44%) in those located in the urban area. Although all of the student, family and school-related characteristic sets were found to be significantly related with the achievement, the student-related characteristics explained the largest amount of variance in achievement. Students’ confidence in math contributed almost the highest amount of variance, and the early numeracy tasks, absenteeism in school, parents’ highest education level, parents’ highest occupation level, early numeric activities before school explained small amounts of variance in students’ math achievement in the schools of all locations.

Study on the Relationship between Combustion Parameters and Cylinder Head Vibration Signal in Time Domain

Combustion-related characteristic parameters, such as the start of combustion (SoC) and the timing of the peak pressure increase rate (PIR), can be used as the feedback signals for the closed-loop control of combustion. A dynamic Finite Element Method (FEM) model was firstly developed to confirm the closely related time period between combustion pressure and vibration. On this basis, a fast processing method was developed to estimate the timings of SoC and the peak PIR in the closely related time period. This method was verified on a twelve-cylinder heavy-duty diesel engine at various engine speed and load. Results showed that the maximum deviation of the two parameters were within 2 °CA and 1.5 °CA, respectively, which suggested that the proposed method had an adequate accuracy.

Age-related characteristic of human intervertebral discs from normal anatomy’s point of view

Aim. To compare morphological characteristics between anterior and posterior parts of human intervertebral discs, taking into account age. Methods. Fragments of 36 intervertebral discs C5C6, D5D6, L5S1 anterior parts taken from deceased persons aged 34 to 94 years, median age 61.0 (50.5; 71.8) years were examined. The comparison group consists of histopathological material obtained from 12 patients with radicular syndrome during planned L5S1 microdiscectomies aged 3577 years, median age 48.5 (43.0; 58.8) years. There were no statistically significant differences in age between the studied groups (p=0.126023). All materials were divided into subgroups depending on the age of the deceased/operated: 3452 and 6094 years for material obtained from the deceased; 3551 and 5877 years for material obtained after surgery. The differences between the three groups were examined by the KruskalWallis test, and quantitative indicators in the two groups were compared by MannWhitney U-test. Results. In the anterior part of the intervertebral discs, signs of degenerative-dystrophic changes were noted in all studied samples. All samples of nucleus pulposus and annulus fibrosus were fibrocartilage with no inflammation. Statistically significant differences (р=0.0283) were obtained in the number of isogenous groups of chondrocytes in intervertebral discs C5C6 anterior part compared with D5D6, L5S1 in individuals aged 3452. Age subgroups (3452 and 6094 years old) differed significantly (р=0.0219) in the number of single chondrocytes according to results of morphometry of anterior part of intervertebral discs L5S1. Anterior and posterior parts of intervertebral discs L5S1 differed statistically significant in the number of isogenous groups of chondrocytes when comparing the subgroup of operated patients aged 3551 years (р=0.008475) with the subgroup of deceased persons aged 3452 years and the subgroup of operated patients aged 5877 years (р=0.033753) with the subgroup of deceased aged 6094 years. Conclusion. Anterior and posterior part of intervertebral discs L5S1 had similar qualitative histological characteristics; however, the number of isogenous groups of chondrocytes in the posterior part of intervertebral discs L5S1 samples indicated a greater effect of compression loading compared to anterior part of the same spinal motion segment.

Women in anesthesiology: Gender stereotypes and prejudice: Women in anesthesiology

Introduction: Women make up an increasing portion of the physician workforce in anesthesia, but they are consistently under-represented in academic anesthesiology and leadership positions. The objective of this study is to provide a current update on the role of women in anesthesiology in Belgrade, Serbia. Methods: A cross-sectional observational study was conducted during September and October 2013 amongst anesthesiologists at ten tertiary health care institutions in Belgrade. The study population was 272 anesthesiologists. Participants' consent and ethical approval were obtained. The questionnaire captured basic sociodemographic and work-related characteristic information: age, sex, level of academic and professional postgraduate education, the managerial position of the section or department. Sociodemographic characteristics were tested in relation to sex by Pearson's chi-squared test. Results: The response rate was 76.2%. Over two-thirds (70.7%) of respondents were women. One-third of female participants (34.5%) and 23.3% of male participants had obtained additional academic achievements; 35.2% of female participants and 40.0 % of male participants had been in managerial positions. Statistically significant gender discrepancies in the additional academic education and upper-rank leadership positions were not detected. Conclusion: Female anesthesiologists in Serbia have achieved parity with men in the highest academic ranks and leadership positions. These women may play an important role in mentoring future generations of female physicians and inspiring them to achieve their professional goals.

Parents’ Creative Self-Beliefs and Creative Activity as Predictors of Family Lifestyle

Family rules, routines, and resources shape children’s creativity. However, little is known about how parents’ creative self-beliefs and creative activity are related to the lifestyle adults create in their families. Family lifestyle might be operationalized as referring to domain-general dimensions of family functioning (cohesion, flexibility, communication, and family satisfaction) and domain-specific factors related to creativity (encouragement to experience novelty and varieties; encouragement to nonconformism; support of perseverance in creative efforts; encouragement to fantasize). To explore the link between parents’ creativity-related characteristic and family lifestyle, 303 Polish parents (57% mothers) of children aged between 6 and 10 (M = 7.99; SD = 1.38) reported on their creative self-beliefs, creative activity, overall family characteristics, and climate for creativity in their families. We found that both parents’ creative self-beliefs (creative self-efficacy and creative personal identity) and their creative activity predict support for creativity in the family and more general balanced and satisfying family relationships. We discuss these findings, point new paths for future research, and suggest interventions in regards to the family creativity-fostering environment.

Stability and Hopf Bifurcation of Nearest-Neighbor Coupled Neural Networks With Delays

In this paper, a high-dimensional system of nearest-neighbor coupled neural networks with multiple delays is proposed. Nowadays, most present researches about neural networks have studied the connection between adjacent nodes. However, in practical applications, neural networks are extremely complicated. This paper further considers that there are still connection relationships between nonadjacent nodes, which reflect the intrinsic characteristics of neural networks more accurately because of the complexity of its topology. The influences of multiple delays on the local stability and Hopf bifurcation of the system are explored by selecting the sum of delays as bifurcation parameter and discussing the related characteristic equations. It is found that the dynamic behaviors of the system depend on the critical value of bifurcation. In addition, the conditions that ensure the stability of the system and the criteria of Hopf bifurcation are given. Finally, the correctness of the theoretical analyses is verified by numerical simulation.

The Relative Importance of Auditor Characteristics Versus Client Factors in Explaining Audit Quality

The U.K. listed firms are used to investigate whether auditor attributes (fixed effects for audit firms, audit offices, and audit partners) add incrementally to baseline models with client controls in explaining audit quality. We document that accounting firm fixed effects add significantly to baseline models. To the extent an accounting firm can standardize its audits, there should be no differences across engagements. However, we find significant interoffice differences, and also significant inter-partner differences within offices. R2 analyses, hierarchical linear models, LASSO (least absolute shrinkage and selection operator) regressions, and R2 decomposition analyses all show that partners are the most important auditor-related characteristic. To better understand the cause of partner variation, we test a set of partner demographic variables (in lieu of partner fixed effects), but we find that they explain little variation, once we control for firm and office differences. We conclude that partner variation is important in explaining audit quality, but understanding the causes requires going beyond existing publicly available demographic data.

Investigation of the Effects of Charging Processes on Lithium-Ion Cells with SiC Anodes at Low Temperatures

Lithium-ion cells with a silicon-graphite (SiC) anode and a nickel-rich cathode are potential candidates for use in electric vehicles (EVs) as this material combination offers high energy densities and low costs. Another desired cell specification that results from an intended short charging time for EVs is the robustness against high charge rates. However, high charge rates can lead to the critical aging mechanism of lithium plating, especially at low temperatures. Investigating this issue, this paper presents a test series on cyclic aging with varying charge rates from 0.2C to 1.5C at ambient temperatures of 0 °C and 10 °C applied to a nickel-rich SiC cell candidate. The resulting effects on cell aging are analyzed with a stripping method, whereby reversible lithium plating can be detected, and a differential voltage analysis (DVA), whereby the overall loss of capacity can be attributed to changes in individual characteristic capacities. The results indicate a degradation sensitivity of SiC anodes at elevated charge rates, evidenced by the loss in the silicon-related characteristic capacity, and question the aging robustness of this material combination.