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Pearlitic steels containing from some 0,8 to 0,95% C belong to the group of unalloyed steels intended for cold drawing or rolling. One of the problems discussed in literature is cracking of pearlitic steel subjected to plastic working, caused by high brittleness of the lamellar precipitations of hard cementite. This issue is extremely important because it affects significantly reduce fatigue strength. The paper presents proposals to modify the process of heat treatment, results in getting a steel with spheroidal structure characterized by better plastic properties, in order to eliminate this problem.

Walls used to fill a frame structure may serve non-load bearing (visual, acoustic or fire separation) or load bearing and stiffening functions which provide geometrical stability of a structure. They are shear walls without any vertical load from higher floors. This paper proposes an algorithm for determining stiffness of a singular frame area, taking into account standards CSA S304.1-04, FEMA 306 and FEMA 274. An attempt was made to cover all valid standards (EN 1996-1-1:2010 and prEN 1996-1-1:2017) applied for designs.

This paper describes principles of verifying load capacity of reinforced masonry walls subjected to horizontal and vertical loading in accordance with EN 1996-1-1:2010 and the draft version of Eurocode 6 (prEN 1996-1-1:2017), These standards specify three methods for positioning reinforcement: the V method only for vertical reinforcement, the VH method that includes both vertical and horizontal reinforcement, and the H method only for horizontal reinforcement. Each of them can be subdivided into cases a, b, and c which differ in the course of standard stresses at the wall edges. This paper focuses on the V method which refers to reinforcement that is positioned vertically. It also presents equations required to determine load-carrying capacity of cross-section against vertical load NEd with neglected vertical reinforcement. Examples of VRd – NEd interaction diagrams are included.

A large number of hydraulic devices and systems are started in low ambient temperatures. A good example of such a device is the hoisting winch on the ship. Starting hydraulic drive units in thermal shock conditions (rapid supply of hot oil to the cold unit) may lead to incorrect operation of the actuating system, for instance, due to the loss of clearance between cooperating elements. The article presents methods to prevent the disappearance of effective clearance in a hydraulic motor started in thermal shock conditions. For this reason, the structure of the hydraulic satellite motor was complemented by elements creating special channels through which hot oil could flow and additionally heat fixed parts of the motor. This solution ensures faster heating of motor housing, thus decreasing the temperature difference between the housing and the satellites during motor start-up in thermal shock conditions.

The article presents research on the morphological architecture of feet and foot structure in rock climbers. A group of climbers is compared to a control group of non-climbers. Examinations determined that the rock climbers had normal structure of the longitudinal arch, but had more disorders of the transversal arch structure than did the control group.

Designers of hydraulically driven machines and devices are obliged to ensure during design process their high service life with taking into account their operational conditions. Some of the machines may be started in low ambient temperature and even in thermal shock conditions (due to delivering hot working medium to cold components). In order to put such devices into operation appropriate investigations, including experimental ones - usually very expensive and time-consuming, are carried out. For this reason numerical calculations can be used to determine serviceability of a hydraulic component or system operating in thermal shock conditions. Application of numerical calculation methods is much less expensive in comparison to experimental ones. This paper presents a numerical calculation method which makes it possible to solve issues of heat exchange in elements of investigated hydraulic components by using finite elements method. For performing the simulations the following data are necessary: ambient temperature, oil temperature, heat transfer coefficient between oil and surfaces of elements, as well as areas of surfaces being in contact with oil. By means of computer simulation method values of clearance between cooperating elements as well as ranges of parameters of correct and incorrect operation of hydraulic components have been determined. In this paper results of computer simulation of some experimentally tested hydraulic components such as axial piston pump and proportional spool valve, are presented. The computer simulation results were compared with the experimental ones and high conformity was obtained.

Aleksandra Skomudek,1,2 Iwona Gilowska,1,3 Ryszard Jasiński,4 Krystyna Rożek-Piechura4 1Department of Physical Education and Physiotherapy, Opole University of Technology, Opolskie, 2Department of Clinical Physiotherapy, 3Department of Biochemistry and Physiology, 4Department of Physiotherapy and Occupational Therapy in Conservative and Interventional Medicine, University of Physical Education in Wroclaw, Wroclaw, Poland Objective: The elderly are particularly vulnerable to degenerative diseases, such as circulatory and respiratory system and vascular system diseases. The objective of this study was therefore to evaluate the distribution of temperature and the dynamics of venous blood flow in the lower limbs (LLs) and to assess the interdependence of these parameters in terms of the somatic components in males and females participating in activities at the University of the Third Age. Materials and methods: The study included 60 females (mean age 67.4 years) and 40 males (mean age 67.5 years). A body composition assessment was performed using the bioimpedance technique – Tanita BC-418MA. The following parameters were examined: fat%, fat mass, fat-free mass, and total body water. The minimal, maximal, and mean temperature values and their distributions were examined using infrared thermographic camera VarioCAM Head. Measurements of the venous refilling time and the work of the LL venous pump were examined using a Rheo Dopplex II PPG. Results: In males, the mean value of the right LL temperature was 30.58 and the mean value of the left LL was 30.28; the P-value was 0.805769. In females, the mean value of the right LL temperature was 29.58 and the mean value of the left limb was 29.52; the P-value was 0.864773. In males, the right limb blood flow was 34.17 and the left limb blood flow was 34.67; the P-value was 0.359137. In females, the right limb blood flow was 26.89 and the left limb blood flow was 26.09; the P-value was 0.796348. Conclusion: Research results showed that the temperature distribution and the dynamics of blood flow are not significantly different between the right and left extremities in both males and females. However, significant temperature differences were found between the gender groups. Significantly higher temperature values in both the right and left extremities were recorded in males than in females. Keywords: thermovision, lower limb, blood circulation

Tests of a full-scale model of slab with the dimensions of 6.30x6.30m, built of TerivaPanel panels were carried out under short-term and long-term load. TerivaPanel panels are partial precast, pre-tensioned concrete slabs with ribs connected at the bottom. The panels have a specially shaped cross-connection (shear key) enabling loads to be transferred between the panels. The tests were carried out under a load placed on the top of the slab. Additionally, the load was applied sequentially. Measurements were made by an electronic method. In one of the stages, long-term testing, the load was applied to one half of the slab to examine the possibility of faulting. The measurements were carried out at monthly intervals, using a geodetic method. The values of vertical displacements at the panel joints (in the middle of the slab) and for central panels along the entire length of the joint were measured.

A letter to the editor is presented in response to the article "Conjugated nitroalkenes in cycloaddition reaction" in the October 2012 issue, which discusses the the quantum-chemical calculation results of the reaction using a fourfold molar excess of the nitroalkene with toluene as solvent.

The article presents the results of particles measurements from a jet engine. Engine parameters were analysed during the actual flight and an attempt was made to map it in stationary tests. Research results were supported by correlation analysis. Based on measurements of particulate matter it was found that the most favourable conditions for particle formation occur during taxiing. Mass distributions were presented and emission factors were determined for three basic phases: taxiing, take-off and approach. The applied research methodology was based on the latest guidelines and was expanded to include propositions related to the analysis of engine operation in real flight conditions.

Particles are products of burning fossil fuels and the basic mechanisms of their formation are widely known. The above issue draws more and more attention of scientists due to the negative impact of solid particles on human health and climate. The emission of particles from aircraft is considered mainly in the case of near airport operations, which results from the applicable homologation regulations. However, due to the impact of exhaust emissions on the climate, it is planned to extend the regulations on limiting exhaust gases at cruising altitudes. The measurement of exhaust emissions in real flight conditions is very difficult to perform from a technical point of view, which is why modelling the environmental effects of air operations and laboratory measurements is very important. The article presents the results of jet engine tests made on the engine dynamometer and the measurements results of particle number concentration in the air during the landing of an aircraft equipped with the same engine as on the dynamometer.

The article compares driving test data using the latest legislative proposals applicable to passenger cars. Several measurements were performed on the same test route in accordance with the RDE test guidelines, which requires a number of criteria to be met. These criteria include: the length of the measuring segments, their overall test time share, and the dynamic characteristics of the drive. A mobile device for reading the EOBD System information was used to record the engine and vehicle operating parameters during tests. This allowed for the monitoring of parameters such as: load value, engine speed and vehicle velocity. The obtained results were then analyzed for their compatibility with the RDE procedure requirements. Despite the same research route, the obtained results were not the same. The analysis also uses the two-dimensional operating time share characteristics expressed in vehicle velocity and acceleration co-ordinates. As a result it was possible to compare the dynamic properties, share of operating time and, consequently, to check the validity of conducted drive tests in terms of their practicability and emission values.

Exhaust emissions from aircraft is a complex issue because of the limited possibility of measurements in flight conditions. Most of the studies on this subject were performed on the basis of stationary test. Engine certification data is used to calculate total emissions generated by air transport. However, it doesnt provide any information about the local effects of air traffic. The main threat to local communities is particulate matter emissions, which adversely affects human health. Emissions from air transport affect air quality, particularly in the vicinity of the airports; it also contributes to the greenhouse effect. The article presents the measurement results of the concentration and size distribution of particles emitted during aircraft landing operation. Measurements were carried out during the landings of aircraft at a civilian airport. It was found that a single landing operation causes particle number concentration value increase of several ten-fold in a short period of time. Using aircraft engine certification data, the methodology for determination of the total number of particles emitted during a single landing operation was introduced.

The article presents the results of studies conducted in the area adjacent to the airport located in Poznan, to determine the impact of aircraft landing operation on the concentration of particulate matter. Measurements were carried out using Engine Exhaust Particle Sizer Spectrometer 3090, enabling the measurement of the particle size distribution. The research allowed to determine the nature of the emitted particles and adds to the evaluation of impact on air quality. The tests were carried out during four aircraft landing operations. In each of the four cases total concentration of particulates number before landing (reference level) and during the landing of the aircraft was measured. In addition, the size distribution of reference level particles and its change after the landing operation was measured. Based on the conducted research, it was found that landing aircrafts have a significant impact on the concentration of particulate matter in the area adjacent to the airport. A single landing operation causes an substantially increase of the value of particle number concentration.

The introduction of new emission limits for exhaust emissions of ship engines contributes to the development of new powertrain solutions. New solutions in the simplest approach concern the reduction of the concentration of sulfur in motor fuels. Typically, the aforementioned fuels have a lower value of viscosity which causes a number of supply system problems. It is becoming more and more common to use fuel cells in engine rooms of various types of marine vessels. Unlike conventional systems that use internal combustion engines, these systems have zero exhaust emissions. Hydrogen, methanol, methane and other substances may be used as a fuel in fuel cells. However, so far the best operating parameters are manifested by cells powered by hydrogen, which is associated with difficulties in obtaining and storing this fuel. Therefore, the use of turbine engines allows the obtaining of large operating and environmental advantages. The paper presents a comparison of the ecological parameters of turbine and piston engines.

The article presents a study on emission measurements in passenger cars in tests conducted under real traffic conditions – Real Driving Emissions using a Portable Emission Measurement System type of equipment. A special feature of the outlined RDE tests is that they were performed in Polish road conditions, and thus their parameters may differ from their counterparts adopted in most European Union countries. Based on the findings vehicle emission conformity factors were developed, characterized as the fractional increase (or decrease) of traffic emissions during the homologation test or under normal operation conditions in relation to the emission limit standards (for chosen emission class) of the vehicle. Conducted research and the calculated conformity factors allowed for the environmental impact assessment of the vehicles of various emission classes, while also allowing early actions to restrict the emissions of selected components in passenger vehicles. The methods and measures used can also be applied to other types of vehicles (e.g. heavy duty or off-road vehicles) or vehicles powered by other fuels.

Regioselectivity and the molecular mechanism of the [3+2] cycloaddition reaction between nitro-substituted formonitrile N-oxide 1 and electron-rich alkenes were explored on the basis of the wb97xd/6-311+G(d) (PCM) quantum chemical calculations. It was established that the thermodynamic factors allow for the formation of stable cycloadducts along all considered models. The analysis of the kinetic parameters of the main processes show that all [3+2] cycloadditions should be realized with full regioselectivity. In all cases, the formation of 5-substituted 3-nitro-2-isoxazolidines is clearly preferred. It is interesting that regiodirection is not determined by the local electrophile/nucleophile interactions but by steric effects. From a mechanistic point of view, all considered reactions should be treated as polar, one-step reactions. All attempts to locate the hypothetical zwitterionic intermediates along the cycloaddition paths were, however, not successful.

This technique-focused observational study explores the impact of a 6-week Nordic Walking (NW) program on physiological and biomechanical aspects in ischemic heart disease (IHD) patients. Twelve male IHD patients (66.2 ± 5.2 years, 12.2 ± 7.5 years of disease duration) were evaluated pre- and post-training for (i) gait parameters, (ii) exercise tolerance using electrocardiographic (ECG) stress test, (iii) a 6-min walk test (6MWT). The NW training, adhering to IHD patient guidelines, involved a 100-m walk at a self-selected, preferred speed without sticks, with classic NW sticks and mechatronic sticks. A mechatronic measuring system, specifically engineered for measuring, diagnosing and monitoring the patient's gait, was integrated into mechatronic sticks. Post-training, significant enhancements were observed in ECG stress test duration, metabolic equivalency, and 6MWT distance, irrespective of the stick type. However, no significant changes were noted in spatiotemporal parameters concerning the measured side, stick utilisation, or type. The results suggest that NW training boosts exercise capacity and refines gait mechanics in male IHD patients. However, the improvement in exercise capacity was not linked to changes in gait mechanics from NW training but rather to the movement during NW gait. Hence, the key to enhancing exercise capacity in IHD patients is the movement during NW gait, not the quality of gait mechanics., (© 2024. The Author(s).)