The effect of the type of lubrication oil on the vibration of industrial planetary gearboxes

The paper presents the results of experimental studies on the effect of the type of oil on the value of vibrations of gearbox housings. There were analysed 4 types of lubricating oils, including 2 types of mineral oils and two types of synthetic oils. All the oils analysed had the same nominal kinematic viscosity of 320 mm²/s at the temperature of 40 °C. The tests were carried out at a testing station for the constant torque load of 2250 Nm and 15 different values of the rotational speed, which allowed obtaining vibration velocity plots as a function of the rotational speed. Based on these plots, it has been found that the results of the measurements of the vibration velocity were very similar for all the lubricating oils in the rotational speed range up to 800 rpm. Above this value, there was observed an impact of resonance phenomena and the measured values of the vibration parameters were changing significantly for different types of oils – higher values of these parameters were characteristic of the plots obtained for gearboxes lubricated with synthetic oils

Prossibilities of increasing the wear resistance of steel chain wheels as a result of changes in their manufacturing process

The paper describes the problems of the operation of chain wheels of armoured face conveyors and the related assurance of the required wear resistance. An analysis of the current methods of manufacturing the chain wheels used in armoured face conveyors has also been performed. It has been found that a dynamic surface treatment can be used in the process of manufacture of these elements. As a part of the study, the results of wear tests for the standard and modernized variants of chain barrels have been presented, which confirmed the validity of the changes made in the process

Advantages and disadvantages of composite pistons for small power combustion engines

The results of technological and metallographic investigations of small dimensions, low power combustion engines piston has been presented. Semi-finished pistons has been produced by gravitations casting of composite material with EN-AC-47000 alloy matrix +15% Al2O3P and EN-AW-6061 alloy matrix +22% Al2O3P. Some small casting defects have been detected during the cutting process of piston made of composite material with EN-AC-47000 alloy matrix +15% Al2O3P. These defects were sources of micro perforations. In the piston made of EN-AW-6061 alloy matrix has been any defects detected

Effects of atorvastatin dose and concomitant use of angiotensin-converting enzyme inhibitors on renal function changes over time in patients with stable coronary artery disease : a prospective observational study

Angiotensin-converting enzyme inhibitors (ACEI) and statins are widely used in patients with coronary artery disease (CAD). Our aim was to compare changes in glomerular filtration rate (GFR) over time in subjects with stable CAD according to atorvastatin dose and concomitant use of ACEI. We studied 78 men with stable CAD referred for an elective coronary angiography who attained the then-current guideline-recommended target level of low-density lipoproteins (LDL) cholesterol below 2.5 mmol/L in a routine fasting lipid panel on admission and were receiving atorvastatin at a daily dose of 10–40 mg for ≥3 months preceding the index hospitalization. Due to an observational study design, atorvastatin dosage was not intentionally modified for other reasons. GFR was estimated during index hospitalization and at about one year after discharge from our center. Irrespective of ACEI use, a prevention of kidney function loss was observed only in those treated with the highest atorvastatin dose. In 38 subjects on ACEI, both of the higher atorvastatin doses were associated with increasing beneficial effects on GFR changes (mean ± SEM: −4.2 ± 2.4, 1.1 ± 1.6, 5.2 ± 2.4 mL/min per 1.73 m2 for the 10-mg, 20-mg and 40-mg atorvastatin group, respectively, p = 0.02 by ANOVA; Spearman’s rho = 0.50, p = 0.001 for trend). In sharp contrast, in 40 patients without ACEI, no significant trend effect was observed across increasing atorvastatin dosage (respective GFR changes: −1.3 ± 1.0, −4.7 ± 2.1, 4.8 ± 3.6 mL/min per 1.73 m2, p = 0.02 by ANOVA; rho = 0.08, p = 0.6 for trend). The results were substantially unchanged after adjustment for baseline GFR or time-dependent variations of LDL cholesterol. Thus, concomitant ACEI use appears to facilitate the ability of increasing atorvastatin doses to beneficially modulate time-dependent changes in GFR in men with stable CAD

The Relationships Between Leadership and Corporate Social Responsibility: Systematic Literature Review

The issues of leadership and corporate social respon-sibility have been thoroughly investigated and widely discussed in the literature but these two concepts have been seldom studied together. The aim of the paper is to identify the key research prob-lems and approaches related to the relationships between leader-ship and CSR manifested in quality publications. The systematic literature survey methodology is applied to identify and analyse key publications in the field. The research sample includes the quality papers retrieved from the Web of Science Core Collec-tion database. The paper discusses main research problems and issues related to the study of relationships between leadership and CSR, research approaches, methods and study contexts. Finally, the paper provides recommendations for further studies related to relationships between the concepts of leadership and corporate social responsibility

Thermal Stability of Austempered Ductile Iron Evaluated in a Temperature Range of 20-300K

The aim of this article was to determine through changes in magnetic properties the stability of the austempered ductile iron (ADI) microstructure during temperature changes in a range of 20 – 300 K. The measurements were taken in a vibrating sample magnetometer (VSM) using Fe27Ni2TiMoAlNb austenitic stainless steel and four types of austempered ductile iron obtained under various heat treatment conditions. The plotted curves showing changes in the magnetisation degree as a function of temperature had a number of characteristic points illustrating changes taking place in the microstructure. For each of the materials examined, the martensite start temperature Ms and the temperature range within which the martensitic transformation takes place were identified

Modern trends in diagnostics of technical condition of material handling equipment drives

This study presents problems of material handling equipment drives as objects of vibration diagnostics, as well as the concept of sensors integrated with a surface exposed to damage on an example of a DiaForce sensor integrated with the surface of the inner race of a rolling bearing according to the solution proposed by Fraunhofer Institute in Braunschweig