Analysis of influencing factors for the dressing process in double side face grinding

In grinding, the design of the dressing process is an essential part of work preparation and restoration of the grinding wheel’s profile and cutting ability. In contrast to most grinding processes, the choice of dressing parameters in double face grinding with planetary kinematics has so far only been experience-based. As a consequence, the dressing process causes a higher degree of tool wear than the machining of the workpieces. A focused design of the dressing process based on a scientific data could help to improve the ecological and the economic efficiency by reducing tool wear and the amount of dressing tools used. In this paper, methods for determining the wear condition and the result of the dressing process, including macro- and microscopic characteristic are presented. This includes a correlation analysis between parameters of wear characteristics and workpiece surface quality. Furthermore, technological investigations are carried out in order to systematically limit the main influencing factors on the dressing process. As a result, the parameters dresser grain size dgd, rotational speed ratio nld and the machined dresser height ∆hd are identified as significant for dressing. The knowledge about their principal influence on the dressing result could provide the basis for further research.

Sexual Dimorphism in Osteoclasts

Osteoclasts are the principal mediators of bone resorption. They form through the fusion of mononuclear precursor cells under the principal influence of the cytokines macrophage colony stimulating factor (M-CSF, aka CSF-1) and receptor activator of NF-κB ligand (RANKL, aka TNFSF11). Sexual dimorphism in the development of the skeleton and in the incidence of skeletal diseases is well described. In general, females, at any given age, have a lower bone mass than males. The reasons for the differences in the bone mass of the skeleton between women and men at various ages, and the incidence of certain metabolic bone diseases, are multitude, and include the actions of sex steroids, genetics, age, environment and behavior. All of these influence the rate that osteoclasts form, resorb and die, and frequently produce different effects in females and males. Hence, a variety of factors are responsible for the sexual dimorphism of the skeleton and the activity of osteoclasts in bone. This review will provide an overview of what is currently known about these factors and their effects on osteoclasts.

Influence of box type and heights on movement strategies of thoracolumbar region and knee in load handling activities

Introduction: Handling activities which includes tasks like lifting, loading, pushing and pulling heavy loads have still been used by workers, in general, this activities are characterized for theirs no corporal limits respect; where the overload in the movements herewith theirs duration and intensity may lead to musculoskeletal diseases, which mainly affect the knee joint and thoracolumbar region of the trunk. Objective: This study intends to evaluate the movement strategies of the spine and knee joint of healthy subjects during a load manual handling course verifying the frequency of these strategies and by what they are influenced (handling high and kind of box). Methods: 42 healthy subjects participated in this study, which had to perform a manual box handling task and unload it in three highs: on the level of the floor, on trochanter’s measured level and shoulder’s measured level. There were utilized four kinds of boxes with variations in: size, material, and presence or not of handles. The conditions (kind of the box and high) were randomized for the subjects. The analysis was made using the unload of the boxes as a reference. Results: the results showed that the characteristics of the boxes (size, material and kind of box, with or without handles) made little influence on the strategies of knee and spine. The principal influence on the posture changes was the difference between the removals and unloads highs. Conclusions: it seems the strategies adopted by the subjects were independent of the characteristics of the load, but dependent of the task demands (i.e., handling high).

The effective thermal conductivity of double-reinforced composites

Polymer based composite materials have a great potential for applications in tribology as dry lubricants since the components comprising the composition may be chosen to fit to various tribological requirements. It is however well known that heat transfer and thermal effects are important for such systems. Systematic experimental studies of temperature effects are time consuming and expensive. In this work, we use a numerical homogenization approach in order to study the principal influence of key composite descriptors of fiber and particle reinforced PEEK on the homogenized heat conductivity. It turns out that the sensitivity of this key parameter on the descriptors can be nicely fitted to a regression model and thus allows for interpolation in the sense of a structure-property-relationship.

Research of the Fatigue Life of Welded Joints of High Strength Steel S960 QL Created Using Laser and Electron Beams

This study investigated the fatigue life of welded joints, in particular, the welds of the high-strength steel S960 QL. The welds were created using unconventional technologies by utilising laser and electron beams. The direct application of the research is intended to be carried out through implementing the results towards the design of tracks for the track-wheel chassis of the demining system Božena 5. The producer’s experience shows the damage found in the current track design. The damage occurred during reversing the vehicle on a sand surface. Our goal was to solve this problem. The information acquired in this research will be a very important input factor for further designs of the track made of the tested material and its welds. The analysis of the residual stresses was also part of this study. The experimental research of the tested material’s fatigue life and welded joints was realised on the specimens loaded using cyclic bending and cyclic torsion. These loads were dominant during the track operation. The fatigue life of the tested material was detected using a device designed by us. The measurement results were processed in the form of the Wöhler’s S–N curves (alternating stress versus number cycles to failure) and compared with the current regulations issued by the International Institute of Welding (IIW) in the form of the FAT curves (IIW fatigue class). The achieved research results indicate that the modern welding technologies (laser and electron beams) used on the high-strength steel had no principal influence on the fatigue life of the tested material.

Principal Influence: A Catalyst for Positive School Climate

This investigation explores the relationships between principal influence and four facets of organizational climate: institutional vulnerability, collegial leadership, achievement press, and professional teacher behavior. Data were collected from 2,033 teachers at 112 elementary schools in two states from the Southern and Midwestern United States. The results of multiple linear regression analyses show that the independent variables of principal influence, SES, and school size combinedto form a significant portion of the variance in organizational climate. The four facets of organizational climate explored in this study provide insight into specific mechanisms through which influential principals can positively affect schools.

Can Placental Thickness predict Fetal Weight?

Background The placenta is the principal influence on fetal birth weight, and it is thought that abnormalities of placental growth may precede abnormalities in fetal growth. Because the placenta may be the first organ to manifest changes of disease in pregnancy, placental features may have a role in screening for pregnancy complications. Aim of the Work The aim this study is to assess the accuracy of placental thickness (estimated by ultrasonography) in predicting fetal weight. Patients and Methods This prospective observational study was conducted at Ain Shams University Maternity Hospital November, 15th, 2016 to November, 1st, 2017. 100 Normal antenatal pregnant women at 24-28 weeks of pregnancy who attended antenatal clinic at the department of obstetrics and gynecology, Ain Shams University Maternity Hospital were recruited, after fulfilling the inclusion and exclusion criteria. Results The predictive rule could estimate actual birth weight with an accuracy of ± 0.450 kg (SEest = 0.450 kg). In visits 1 and 2; ± 0.448 kg (SEest = 0.448 kg) in visit 3. Conclusion The actual birth weight was regressed on the placental thickness using simple linear regression to obtain a predictive rule. There is very weak correlation between the actual neonatal weight and placental thickness. The current study deduced a new formula for correction of EFW using placental thickness which has a promising role to offer in the prediction of birth weight.

Investigation into the mechanism of thin filament regulation by transient kinetics and equilibrium binding: Is there a conflict?

Striated muscle contraction occurs when myosin undergoes a lever-type structural change. This process (the power stroke) requires ATP and is governed by the thin filament, a complex of actin, tropomyosin, and troponin. The authors have used a fast-mixing instrument to investigate the mechanism of regulation. Such (pre–steady-state kinetic) experiments allow biochemical intermediates in a working actomyosin cycle to be monitored. The regulatory focal point is demonstrated to be the step that involves the departure of inorganic phosphate (i.e., AM-ADP-Pi → AM-ADP). This part of the cycle, which lies on the main kinetic pathway and coincides with the drive stroke, is maximally accelerated ∼100-fold by the combined association of ligands (Ca[II] and rigor myosin heads) with the thin filament. However, the observed ligand dependencies of the rates of Pi dissociation that are reported herein are at variance with predictions of models derived from experiments where ATP hydrolysis is not taking place (and myosin exists in a nonphysiological form). It is concluded that the principal influence of the thin filament is in setting the rate of Pi dissociation and that physiological levels of regulation are dependent upon the liganded state of the thin filament as well as the conformation of myosin.

Gerard, Alexander (1728–95)

Alexander Gerard was Professor of Moral Philosophy and Logic (1752) and Professor of Divinity (1759) at Marischal College, and Professor of Divinity (1773) at King’s College, Aberdeen. A leading member of the Aberdeen Philosophical Society, he wrote a new plan of education for Marischal College as well as works on divinity. He is best known, however, for his Essay on Taste (1759). In 1774, he returned to the subject with An Essay on Genius. Gerard was associated with Thomas Reid (1710–96) in the Philosophical Society until Reid’s transfer to Glasgow in 1764. The work of David Hume (1711–76) was a principal influence.

PENGARUH KEPEMIMPINAN TERHADAP KINERJA GURU PADA SEKOLAH MAN 1 MEDAN

This study aims to determine whether the leadership the principal influence on Teacher Performance in School MAN 1 Medan . To determine the influence of independent variables on the dependent variable we used the coefficient of determination ( R2 ) . It is also used partial test (t test) to determine whether it is still the independent variables significantly influencing variables . Filing is done at the 95% confidence level or confidence level α = 0.05 % error ( 5 % ) . The number of objects or samples of multiple linear regression. The coefficient of determination (R2) obtained at 0.082 or 8.2% indicates that the variable Leadership able to explain the variations that occur in the performance of teachers in the School of MAN 1 Medan, while the remaining 91.8% is explained by other variables not examined in this study , Based on hypothesis testing (test T) obtained tcount Leadership for smaller 0.847 leadership variables in the appeal ttabel 1.671 and 0.421 significance value greater than 0.05, then H0 is accepted and H1 is declined, thus partially leadership variable does not affect the performance of teachers in school MAN 1 Medan