A method of predicting the best conditions for large-size workpiece clamping to reduce vibration in the face milling process

The paper presents an innovative method of solving the problem of vibration suppression during milling of large-size details. It consists in searching for the best conditions for clamping the workpiece based on a rapid modal identification of the dominant natural frequencies only and requires repetitive changes in the tightening torque of the clamping screws. Then, by estimating the minimum work of the cutting forces acting in the direction of the width of the cutting layer, it is possible to predict the best fixing of the workpiece. Application of the method does not require the creation and identification of a computational model of the process or preliminary numerical simulations. The effectiveness of this method was confirmed by the evaluation of the Root Mean Square (RMS) of the vibration level in the time domain observed during the actual face milling process. The worst results were obtained for the configuration of supports tightened with a torque of 90–110 Nm, and the best—with a torque of 50 Nm.

Morphometry of Cerebral Arterial Bifurcations Harbouring Aneurysms: A Case-Control Study On 253 Patients

Background Conclusions from studies evaluating vessel dimensions and their deviations from the values resulting from the principle of minimum work (PMW) on the formation of intracranial aneurysms (IAs) are still inconclusive. The aim of our study was the morphometric analysis of cerebral arterial bifurcations harbouring aneurysms. Methods The study comprised 147 patients with basilar artery (BA) and middle cerebral artery (MCA) aneurysms, and 106 patients constituting the control group. The following morphometric parameters were evaluated: the radii of vessels forming the bifurcation, the junction exponent, the values of the bifurcation angles (Φ1 and Φ2 angles between the parent vessel trunk axis and the larger or smaller branches, respectively; α angle, total bifurcation angle) and the difference between the predicted optimal and observed branch angles. Results The analysed parameters for internal carotid artery (ICA) bifurcations were not significantly different among the groups. MCA and BA bifurcation angles and the radii of the parent MCA and BA vessels with aneurysms were significantly higher compared to the control group. The differences between the predicted optimal and observed branch angles were significantly higher for BA and MCA bifurcations with aneurysms compared to the control group. The mean junction exponent for bifurcations in the circle of Willis (i.e., ICA and BA bifurcations, respectively) and MCA bifurcations with aneurysms was significantly lower than the theoretical optimum and not significantly different among the groups. In a multilevel multivariate logistic regression analysis, the branch angles and the radius from the parent vessel were significant independent predictors of the presence of IAs. The ROC analysis indicated that the α angle was the best performer in discriminating between aneurysmal and non-aneurysmal bifurcations. Conclusions The dimensions of the arteries forming the circle of Willis do not follow the PMW. The deviation from optimum bifurcation geometry for bifurcations beyond the circle of Willis (particularly a wider radius of the parent artery and a wider total bifurcation angle) may lead to the formation of IAs. Further studies are warranted to investigate the significance of vessel dimensions and the bifurcation angle on the magnitude of the shear stress in the walls of arterial bifurcations.

A Method of Predicting The Best Conditions for Clamping a Large-Size Workpiece in Order To Reduce Vibrations in The Milling Process

The paper presents an innovative method of solving the problem of vibration suppression during milling of large-size details. It consists in searching for the best conditions for clamping the workpiece based on a rapid modal identification of the dominant natural frequencies only and requires repetitive changes in the tightening torque of the clamping screws. Then, by estimating the minimum work of the cutting forces acting in the direction of the width of the cutting layer, it is possible to predict the best fixing of the workpiece. Application of the method does not require the creation and identification of a computational model of the process or preliminary numerical simulations. The effectiveness of this method was confirmed by the evaluation of the Root Mean Square (RMS) of the vibration level in the time domain observed during the actual face milling process.

Description the Importance of Developing a Self-Reliance Instrument for Schizophrenic Patients in the Hospital Setting

Background: The level of independence among schizophrenia patients is still a problem that must be resolved. The development of appropriate relevant instruments is needed. This study aims to develop a nursing rehabilitation therapy instrument to increase the independence of schizophrenia patients in the hospital setting. Methods: This study used a research and development study design. The study was conducted in a Psychiatric Hospital in Surabaya, Indonesia from August to December 2020. The total sample in this study consisted of 100 nurses determined by a simple random sampling technique. In addition, 50 medical records were observed. The inclusion criteria were nurses who cared for patients with schizophrenia with a minimum work experience of 1 year. Respondents were excluded from the study if they did not follow the study through to completion. The data collection process was done online by filling in a Google form. The data was analysed using descriptive statistics and a FGD followed with 10 nurses to discuss the new instrument. Results: The data found that a rehabilitation therapy instrument is not currently available (53%). The FGD results show that it is necessary to develop the nurse’s knowledge and to provide adequate facilities and rooms, as well as to develop instruments to use as measuring tools in order to evaluate the rehabilitation therapy given. Conclusion: Rehabilitation therapy instruments are important to develop for schizophrenia patients. It is hoped that the development of the instrument in this study will optimise the rehabilitation of schizophrenia patients.

Pengaruh Kepuasan Kerja dan Kontrak Psikologis Terhadap Intention To Quit dengan Komitmen Organisasi Sebagai Variabel Intervening (Studi Pada Pt. Krakatau Steel, Tbk)

The purpose of this study is to analyze the effect of job satisfaction and psychological contracts on intention to quit with organizational commitment as an intervening variable. The population used in this study are operational employees of PT Krakatau Steel Tbk. who have become permanent employees with a minimum work period of 1 year and a minimum education level of high school and equivalent. The number of samples used in this study were 190 respondents. Data collection using a questionnaire. This study uses structural equation modeling (SEM) analysis with AMOS software as an analysis tool. The results showed that job satisfaction had a negative and significant effect on intention to quit, psychological contracts had a negative and insignificant effect on intention to quit, job satisfaction had a positive and significant effect on organizational commitment, psychological contracts had a positive and significant effect on organizational commitment and organizational commitment had a significant effect on organizational commitment. negative and significant on the intention to quit.

Prison breakthrough

There is a consensus among researchers that information systems brought and continue to bring a fourth revolution in organisations around the world. These systems made an immense contribution by incorporating various functions into one system, thus enhancing the capabilities of organisations with minimum work effort. Correctional facilities have also made the break to add information systems in prisons for better decision-making. This study utilised literature review to critically examine the use of information systems within the correctional facilities in African countries with a view to determine how the resultant records from the system are managed. Findings reveals that information systems used in prisons have simplified the flow of information and the records management functions in correctional facilities in some African countries. However, the majority of correctional facilities in countries such as South Africa are still using the traditional method of records management mostly because of financial constraints and lack of support from the government. The study recommends that correctional facilities should consider exploring the possibility of benchmarking and collaborating with other key sectors for effective implementation of information systems and management of resultant records.

A robust measure of event isotropy at colliders

We introduce a new event shape observable — event isotropy — that quantifies how close the radiation pattern of a collider event is to a uniform distribution. This observable is based on a normalized version of the energy mover’s distance, which is the minimum “work” needed to rearrange one radiation pattern into another of equal energy. We investigate the utility of event isotropy both at electron-positron colliders, where events are compared to a perfectly spherical radiation pattern, as well as at proton-proton colliders, where the natural comparison is to either cylindrical or ring-like patterns. Compared to traditional event shape observables like sphericity and thrust, event isotropy exhibits a larger dynamic range for high-multiplicity events. This enables event isotropy to not only distinguish between dijet and multijet processes but also separate uniform N-body phase space configurations for different values of N. As a key application of this new observable, we study its performance to characterize strongly-coupled new physics scenarios with isotropic collider signatures.

Pengukuran produktivitas lini produksi gula rafinasi dengan pendekatan Objective Matrix (OMAX)

Productivity measurement has an important role in evaluating and establishing the next strategy in increasing productivity levels. This study aims to determine the level of productivity of a refined sugar company and provide suggestions for improvements to increase the level of productivity. This research uses the Objective Matrix (OMAX) method with five ratio indicators, namely yield achievement, actual production achievement criteria, boiler natural gas consumption criteria, electricity consumption criteria, and employee absenteeism criteria. This study uses company data for 2018 in accordance with company recommendations. The results showed that for one year, the productivity values and performance index differed each month. The performance index with the highest point was in February, which reached 426.3% and in May, which reached 306%. Based on the traffic light system, ratio 1 has six minimum performance periods, ratio 2 has eight minimum performance periods, ratio 3 has four minimum performance periods, ratio 4 has four minimum work periods, and ratio 5 has five minimum work periods. Improvement steps that can be done to improve the actual achievement of production are the provision of regular training to enhance skills and cooperation between operators, improvement of maintenance management systems, development of air circulation, and supplier evaluation. The OMAX method can identify performances that have below standard production, and recommendations for improvement can be prioritized on the ratio that experiences the most substandard performance.

ENERGY BALANCE DURING FREIGHT ELECTRIC LOCOMOTIVE OPERATION

The purpose of this work consists in obtaining power indices of a freight electric locomotive at the specified schedule of motion, but at different laws of speed changes and on different track profiles. CAD methods are used, at that, the further comparison of the results obtained with the records of the locomotive crew recorder has shown an actually complete coincidence. As expected, a minimum work performed for a train hauling is achieved in an ideal case – at the motion without stops at a constant speed on a straight horizontal track. When moving along an actual profiled track a work performed for hauling changes by a difference of potential energy of gravity in the initial and end points. Often accelerations and slowdowns result in the work increase for hauling, for that there are obtained quantity values. In order to avoid excess power waste it is necessary to move possibly without sharp accelerations and hard braking. To support motion uniformity it is expedient to use a speed controller. There are obtained the values of a specific work for train hauling in different cases which define limits for a purpose index on the

TEACHER PERFORMANCE MANAGEMENT CYCLE BASED ON EMPLOYEE’S TARGET

The purpose of this study is to know how teacher performance management as a continuous performance process to equalize individual teacher goals and educational institutions also teacher performance series starting from the planning, implementation and evaluation phase which are oriented to minimum work standards in order to obtain income eligibility, benefits, and promotion or rank only which resulting in the performance of teachers dwelling on matters of an administrative nature and setting aside performance processes that produce output and outcome according to the objectives of educational institutions. This research used a qualitative research design by concerning to a phenomenon approach. Data collection techniques used by some steps such as observation, interviews and documentation. Data analysis included single site analysis and cross-site analysis with data analysis techniques; data reduction, data presentation, and conclusions. This research produced four main findings among others; first, in pre-cycle stage with preparation for assessment and creating a teacher performance assessment team; second, the phase of planning with the phase of defining, discussing roles, responsibilities, and measurable expectations; third, the phase of coaching with the phase of observation, monitoring, support, feedback, and appreciation; the four phase of the teacher performance management cycle are performance evaluations.