TIG brazing technology for zinc-coated sheet steel for bodywork

We propose a method for the assessment of the state of welded joints in terms of arc voltage signals and feed rate appraisal. The signals were recorded during laboratory tests. For the appraisal of the signals, we applied numerical parameters such as, for instance, kurtosis. On the basis of analysis results, we developed diagnostic rules which were written in the binary diagnostic matrix. The proposed method has been implemented in the form of software, the correctness of which has been verified on experimental data.     

Application of averaged instantaneous power spectrum for diagnostics of machinery operating under non-stationary operational conditions

Vibration analysis of machines operating under non-stationary operational conditions requires special attention. This refers to the necessity of use of order tracking algorithms together with additional advanced signal processing methods, especially when faults indicators of interest are located in resonance frequency ranges.     

Physico-chemical properties and antibacterial activity of modified egg white—lysozyme

Lysozyme (N-acetyl-muramyl-hydrolase E.C. 3.2.1.17) is a low-molecular enzyme (14,400 Da) found in body secretions, systemic fluids and tissues of humans and animals. Antibacterial activity of lysozyme monomer is limited first of all to Gram-positive bacteria, which is connected with the structure of the cell wall. This enzyme catalyzes hydrolysis of β-glycoside bonds (1–4), releasing N-acetylglucosamine and N-acetylmuramic acid. The spectrum of antibacterial activity of lysozyme may be extended thanks to modifications of the enzyme. The aim of the study was to assess antibacterial activity, hydrolytic activity and surface hydrophobicity of different forms of lysozyme. Chemical and thermo-chemical modification of lysozyme was performed, and the antibacterial action of lysozyme monomer and modified preparations were compared. It was found that in comparison with monomer and the control, all modified preparations exhibit effective action against Gram (−) bacteria Pseudomonas fluorescens. A particularly effective action was found in case of lysozyme subjected to thermo-chemical modification, which was characterized by the highest proportion of oligomeric forms and the highest hydrophobicity.     

The impact of liberalisation of the electricity market on the hard coal mining sector in Poland

The liberalisation of the electricity market changed the conditions of operation not only for the power industry, but also for related sectors. One of the particularly sensitive industries in Poland is coal mining, which is the result of coal-based structure of electricity generation. As it is more difficult, in the liberalised market, to burden consumers with all the costs, electricity producers are eager to transfer the risk of operation to the suppliers. That increases uncertainty about the future of the hard coal industry. The aim of this paper was to quantitatively estimate the impact that liberalisation of the electricity markets may have on the coal mining sector in Poland. First of all, the possible areas of that impact were identified. Then the model, which involved detailed relations in the impact areas identified, was developed and employed to evaluate the performance of the mining sector. The comparison of scenarios of a monopolistic electricity sector with a liberalised one enabled an estimation of the scale of the impact on the mining sector to be made. The results showed that liberalisation causes decreased coal consumption and decreased operating profits in coal companies. However, some savings in electricity costs are possible for coal producers.     

XPS studies of perovskites surface instability caused by Ar+ ion and electron bombardment and metal deposition

X-ray Photoelectron Spectroscopy (XPS) was used to study the influence of low energy Ar⁺ ion bombardment, electron bombardment and Pt deposition on the SrTiO₃ (STO) single crystal electronic structure. Atomic composition changes were found and attributed to chemical reconstruction of the STO surface. A clear correlation between the presence of conducting, low Ti oxidation states in valence band and core level changes was detected. A strong effect caused by electron irradiation was ascribed to the electroreduction process. The influence of lanthanum doping on surface instability of STO was also discussed. The La doped sample (STO: 3,75% La) was found to be modified upon Pt metal deposition to a higher degree than pure STO crystal.     

Technical foundations for noninvasive assessment of changes in the width of the subarachnoid space with near-infrared transillumination-backscattering sounding (NIR-TBSS)

This paper presents technical foundations for a new technique of near-infrared transillumination-backscattering sounding, which is designed to enable noninvasive detection and monitoring of changes in the width of the subarachnoid space (SAS) and magnitude of cerebrovascular pulsation in humans. The key novelty of the technique is elimination of influence of blood flow in the scalp on the signals received from two infrared sensors-proximal and distal. A dedicated digital algorithm is used to estimate on line the ratio of the powers of received signals, referred to as two-sensor distal-to-proximal received power quotient, TQ (t). The propagation duct for NIR radiation reaching the distal sensor is the SAS filled with translucent cerebrospinal fluid. Information on slow fluctuations of the average width of the SAS is contained in the slow-variable part of the TQ (t), called the subcardiac component, and in TQ itself. Variations in frequency and magnitude of faster oscillations of the width of that space around the baseline value, dependent on cerebrovascular pulsation, are reflected in instantaneous frequency and envelope of the fast-variable component. Frequency and magnitude of the cerebrovascular pulsation depend on the action of the heart, so this fast-variable component is referred to as the cardiac component.     

How to get the most out of two phosphorus chemistries. Studies on H-phosphonates

The biological importance and practical significance of phosphate esters and their analogues have been the major driving forces for research in various areas of synthetic organic phosphorus chemistry. In this Account, the authors' studies on the development of a comprehensive H-phosphonate methodology and the underlying chemistry for the preparation of biologically important phosphate esters and their analogues are briefly discussed.     

Effects of the abdominal belt on muscle-generated spinal stability and L4/L5 joint compression force

The goals of this study were (1) to determine the effects of abdominal belts on muscle-generated active lumbar spine stability, (2) to determine their effect on the subsequent joint compression force at L4/L5 and (3) to determine whether the effective stability of the spine could be predicted by the active spine stability and belt condition. Electromyographic (EMG) and trunk stiffness data from a previously reported experiment in which 10 subjects performed quick-release tasks (perturbation) with and without an abdominal belt were used as inputs to biomechanical models to estimate the active spine stability and effective stability of the spine, respectively. The subjects exerted isometric trunk flexion, extension and lateral bending trials at 0 and 80% of maximum intra-abdominal pressure when the resisted force was suddenly released. Wearing an abdominal belt had no significant effect on either the muscle-generated lumbar spine stability or the L4/L5 joint compression force in any direction. The effective stability of the spine was adequately predicted by the active spine stability and the effect of the belt, which accounted for approximately 34% of the effective spine stability. The study demonstrated that the abdominal belt contributed to the passive stability of the lumbar spine and did not change the active stability for tests performed within the same experimental session.