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In this work, energetic coordination compounds (ECCs) of transition metals (Fe, Ni, Cu, Zn) containing aliphatic amines as ligands were synthesized: ethylenediamine; 1,3-diaminopropane; tris(2-aminoethyl)amine; tris(3-aminopropyl)amine. The compounds were investigated in terms of ignition/explosion temperature, friction and impact sensitivity. For selected compounds, structural characterisation was presented (IR-ATR spectroscopy, Raman spectroscopy) and their morphology was determined (SEM, powder XRD). They were also investigated by differential scanning calorimetry (DSC). In order to assess the potential application of selected ECCs in detonators, underwater explosion tests were carried out, determining energetic performance. The results achieved for detonators containing ECCs were compared with those for reference detonators (containing pentaerythritol tetranitrate, PETN), indicating their potential use as a "green" alternative to nitric acid esters. [ABSTRACT FROM AUTHOR]

Average surface height and maximum amplitude can affect surface functions. In the industry, these parameters can be obtained based on profile measurements. However, variability in maximum profile height is high. A more stable parameter can be obtained from the results of the areal surface topography measurements as the average value of the parallel profiles. The aim of this study is to establish this parameter directly from the result of the areal surface texture by correcting the maximum surface height to material ratios in the range of 0.13–99.87%. This method was tested by measuring 100 surface topographies with a stylus profilometer and a white light interferometer. It can be utilized correctly for deterministic textures and random one- and two-process surfaces for which the correlation between neighboring profile ordinates is not very high. In other cases, the method should be modified. Employing this method, the maximum profile amplitude Pt and parameters characterizing the average profile height Pq, Pa, and the ratios Pq/Pa and Pp/Pt describing the shape of the profile ordinate distribution can be correctly estimated. Pq/Pa and Pp/Pt were more stable than the kurtosis Pku and skewness Psk. The corrected maximum height S±3σ can be adopted as a parameter that characterizes the areal surface texture as more stable than the maximum surface height St. Pq/Pa and Pp/Pt were more steady than kurtosis Pku and skewness Psk. [ABSTRACT FROM AUTHOR]

A novel procedure for the generation of cylinder liner surface texture during finish honing and plateau honing was presented. An idea of surface creation depends on superposition of one-process arbitrary oriented one-directional texture of Gaussian ordinate distribution on machined or modeled base surface. This iterative procedure depended on the type of honing process. In finish honing, in each iteration the vertical distance of the superimposed surface from the base surface increased in the defined step. In the plateau honing process, the mean plane of the superimposed surface was embedded at depth corresponding to the same material ratio of the base surface. The models presented were calibrated and validated by a honing experiment. The relative errors of predicting parameters Spq, Svq, Smq and Sal during plateau honing were less than 20%, in most cases they were smaller than 7%. [Display omitted] • Cylinder liner surfaces created in plateau honing were modeled using superimposition approach. • The models were calibrated and validated by a honing experiment. • The parameters describing honed liner textures using diamond and ceramic stones were correctly anticipated. • Errors of predicted parameters characterizing cylinder liner surface textures were usually less than 10%. • High discrepancy between modeled and experimental values of the peak height Sp occurred. [ABSTRACT FROM AUTHOR]

The paper presents the temperature field effect on the dynamic stability problem of plates with imperfection. The main objective is to conduct numerical investigations which show the relations between the imperfection ratio and plate dynamic response in a thermal environment. The plate is composed of three layers: thin facings and a thicker core. The plate can be loaded mechanically and thermally or only thermally. The facings are mechanically compressed with the forces acting in a plane. The temperature field model is defined by the temperature difference, which occurs between the plate edges. Two plate models are examined as follows: built using the approximation methods – orthogonalization and finite differences – and composed of finite elements. The analytical and numerical solution procedure is the main one, which is the proposal to perform the problem analysis. The plate reaction is described by the obtained values of the critical temperature differences for plates loaded only thermally and by the critical mechanical loads and the corresponding temperature differences for plates loaded mechanically and subjected to the uncoupled temperature field. The effect of the plate imperfection ratio under time-dependent loads is shown by numerous observations and results, which are shown graphically. The importance of the imperfection ratio on the plate's dynamic stability response in complex loading conditions is studied. [ABSTRACT FROM AUTHOR]

Gallstone ileus is a rare disease, arising due to intestinal obstruction caused by cholelith. It affects mainly patients between 60–70 years old and is a consequence of biliary intestinal fistula. Due to its uncommonness and the patients' age and comorbidities there is a lack of precise treatment and diagnostic guidelines. The aim of this article is gallstone ileus literature review and case report from Independent Public Clinical Hospital No. 1 of Pomeranian Medical University in Szczecin, Department of General, Minimally Invasive and Gastroenterological Surgery Department. [ABSTRACT FROM AUTHOR]

Surface topography in general is not easy to characterize due to a great number of different features that appear on it. It is still more challenging for machined textured surfaces that are of high functional significance for tribological purposes. For practical reasons, there is a need to describe such surfaces using only a small number of parameters. Which of them represent surface details the best is still an open issue. To find out which parameters can be the most suitable in that case, three groups of machined textured surfaces were prepared. They were plateau-honed cylinder surfaces made of gray cast iron, steel, and bronze surfaces with isolated dimples and steel surfaces after abrasive blasting followed by lapping. All of them were measured by means of a white light interferometer. Different parameters and relationships were evaluated and based on them correlation and regression analyses were used. The basic description contained statistically independent parameters that can be used in production control, while the wider description in scientific research. In general, parameters of random surfaces were more intercorrelated than those of surfaces with isolated dimples. As was found for the basic description of random two-process surfaces, five parameters were enough while description of textured surfaces with isolated oil pockets needed six. In wider, scientific description, regardless the surface type seven parameters contained the necessary information about the surface. It was also proved that a pair of parameters, the emptiness coefficient Sp/Sz and Sq/Sa, can describe the shape of the ordinate distribution of machined textured surfaces better than, for example, skewness Ssk and kurtosis Sku, commonly used for that purpose. [ABSTRACT FROM AUTHOR]

Tortuosity of the colon is an important parameter for predicting the course of colonoscopy. Computed tomography scans of the abdominal cavity were performed in 224 (94 female, 130 male) adult subjects. The number of acute (angle not exceeding 90°) bends between adjacent colonic segments was noted and analyzed. Data were analyzed for correlation with gender, age, height and weight. An artificial intelligence algorithm was proposed to predict the course of colonoscopy. We determined the number of acute flexions in females to be 9.74 ± 2.5 (min–max: 4–15) and in males to be 8.7 ± 2.75 (min–max: 4–20). In addition, more acute flexions were found in women than in men and in older women (after 60 years) and men (after 80 years) than in younger ones. We found the greatest variability in the number of acute flexures in the sigmoid colon (0–9), but no correlation was found between the number of acute flexures and age, gender, height or BMI. In the transverse colon, older and female subjects had more flexures than younger and male subjects, respectively. Older subjects had more acute flexures in the descending colon than younger subjects. There are opportunities to use the number of acute flexures (4–7, 8–12, more than 12 flexures) to classify patients into appropriate risk categories for future incomplete colonoscopy. On this basis, we predicted troublesome colonoscopies in 14.9% female and in 6.1% male subjects. [ABSTRACT FROM AUTHOR]

The effect of cylinder liners on engine performance is substantial. Typically, the cylinder surfaces were plateau honed. However, recently additional dimples or grooves were created on them. This work discusses the tribological impacts of textured cylinder liner surfaces based on a review of the literature. The results of the experimental research obtained using test rigs and fired engines were critically reviewed. In addition, the results of the modeling are shown. Circular oil pockets and grooves perpendicular to the sliding direction of piston rings of small depths were typically used. Surface texturing of the cylinder liners governs lubrication between the cylinder liner and the piston ring by an increase in oil film thickness near the reversal points leading to reductions in friction force and wear and in the fired engine to a decrease in fuel consumption and to an increase in power or torque. The correct texturing pattern ensures a decrease in the oil consumption, blow-by, and emissions of the internal combustion engine compared to plateau-honed surfaces. Considerations of future challenges are also addressed. The volume of lubricant reservoir in surface topography, called oil capacity, should be a substantial parameter characterizing textured surfaces. [ABSTRACT FROM AUTHOR]

Surface texture measurement, characterized by areal parameters, is very susceptible to measurement errors. Various types of errors differently affect surface texture parameters. In this paper, two types of measurement errors were investigated. To analyze the impact of the presence of scratches, circular valleys of various diameters were added to surface textures measured by a white light interferometer. Measurement errors were larger for higher scratches. Skewness and kurtosis were mostly affected by the presence in valleys, and changes of spatial parameters were also comparatively high. The difference between the results of measurement of the same surface details two times after a break of three months was also studied. This difference was caused by errors of relocation, spikes and non-measured point presences, high-frequency noise, and surface ageing. Spatial parameters were found to be the most stable. [ABSTRACT FROM AUTHOR]

Giant hiatal hernias with massive displacement of abdominal organs into the thoracic cage are known as non-typical hiatal hernias. They can occur with few clinical symptoms across many years, which often makes the diagnosis difficult. The method of choice for diagnosis is computer tomography. We present 4 cases of a giant hiatal hernia. Three out of 4 patients have been operated on because of an obstruction in the upper digestive system, whereas 1 had elective surgery. In all cases, we performed a fundoplication with good results and no mortality. [ABSTRACT FROM AUTHOR]

This paper presents an evaluation of the static stability of complex, composite annular plates with layers having auxetic properties. The main objective of the numerical investigations is the development of a plate model, which uses an approximate solution based on orthogonalization and finite difference methods. The three-layered plate is composed of auxetic facings and a soft, foam core. The material properties of the facings are characterized by Poisson's ratio, the values of which are variously positive and negative. The results obtained for an auxetic plate were compared on the basis of the results for a plate with traditional facings and a plate model built of finite elements. Additionally, in order to verify the calculation results, an analysis of the homogeneous plate was performed. Two plate models built of finite differences and finite elements were compared. The wide image of buckling responses of the examined plates was created on the basis of the calculation results of both compressed and radially stretched plates. An increase in the values of the critical static loads with increasing absolute value of Poisson's ratio of auxetic facings is one of the observations. [ABSTRACT FROM AUTHOR]

Esophagoenteral anastomotic leaks are one of the most serious complications of gastric cancer surgeries. Leaking anastomosis has a negative impact on patient's prognosis as it translates into increased reoperation rates, direct and indirect mortality, as well as increased risk of cancer recurrence. Literature contains reports on the use of additional measures aimed at preventing anastomotic leaks. Collagen matrices with tissue adhesives used to prevent anastomotic leaks following D2 gastrectomy with Roux-en-Y anastomosis have not been described well in Polish literature. However, international reports on such use of these materials are available. Collagen matrices have been successfully applied in selected patients undergoing total or subtotal gastrectomy at the Department of General, Minimally Invasive, and Gastroenterological Surgery. We hereby present our experience in a group of 6 patients presenting with anastomotic leak risk factors. [ABSTRACT FROM AUTHOR]

The surface of cylinder liner is tribologically important. In most cases, it has a two-process cross-hatched structure created by the plateau honing process. Because the surface topography of cylinder liners is complicated, its analysis is challenging. Special methods have been used to analyse the textures. In this article, first, the parameters in the standard are reviewed. Next, the methods for selecting the reference elements are presented. Other comprehensive methods of cylinder surface analysis are described. Finally, methods of cylinder texture modelling are analysed. • Characterisation of a plateau-honed cylinder surface. • Standard parameters for a plateau-honed surface. • Reference elements. • Non-standards approach to a plateau-honed surface. • Cylinder liner texture modelling. [ABSTRACT FROM AUTHOR]

The main objective of this work is to model wear of a disc which was subjected to dry contact with a ball in unidirectional sliding. Tribological tests of sliding pairs were carried out using a tribological tester T-11 in a ball-on disc configuration. Stationary balls made of 100Cr6 steel with a hardness of 62 ± 2 HRC co-acted with rotating discs with 42CrMo4 steel with a hardness of 40 ± 2HRC. Discs were machined by lapping, grinding, milling, and vapour blasting. The values of the Sq parameter of disc surfaces were between 0.1 and 5.86 µm. Wear volumes of the discs were lower for bigger roughness heights. The simulation of disc wear was conducted on the basis of the repetitive contact between sliding surfaces. Strong correlation was achieved between the modeled and measured volumetric wear levels. [ABSTRACT FROM AUTHOR]

• Types of errors in surface metrology. • Analysis of characteristic errors for the stylus method. • Analysis of errors typical for optical methods. • Comparison of results obtained by contact and optical methods. • Analysis of sensitivity of parameters to various measurement errors. The surface texture is functionally important. It can be characterised using a set of parameters. The errors in determining the parameters should be small. In this paper, areal surface texture parameters are presented. The errors in the determination of areal parameters are studied, with focusing on the field parameters. Inaccuracies typical for stylus and optical methods are considered. Errors caused by the digitisation process, errors created during data processing, and parameter variations on typical surfaces are studied. The relations between measurement errors and surface texture parameters are analysed and discussed. On the basis of this review, parameters of considerable changes due to measurement errors and stable parameters are selected. Spatial parameters are robust, while the skewness and kurtosis are susceptible to measurement errors. Feature parameters with high sensitivity to measurement errors should not be used during routine measurements. [ABSTRACT FROM AUTHOR]

The paper presents a solution to the dynamic response of three-layered, annular plates that are thermo-mechanically loaded. Time-dependent forces are considered to act on the facings of the plate. The thermal loading is defined by a flat, axisymmetric temperature field whose profile is expressed by the stationary or increase in time temperature differences between the plate edges. The cases of the plates loaded only thermally or mechanically have been examined. The problem has been solved analytically and numerically using the approximation methods: orthogonalization and finite difference. The selected reactions of an exemplar plate have been compared with the results obtained for the plate analyzed by the finite element method (FEM). The critical temperature differences and critical loads and corresponding dynamic buckling modes have been analyzed in detail. The numerous results presented for the dynamic responses have an important and practical meaning in the design process of plate structures subjected to complex thermo-mechanical loads. [ABSTRACT FROM AUTHOR]

4-methyl-3-heptanol, a monohydroxy alcohol with a relatively small dielectric Debye process, is studied in wide ranges of temperature (143 K < T < 308 K) and pressure (0.1 MPa < p < 864 MPa). When monitored under isochronous conditions, i.e., focusing on constant relaxation times, as well as under isothermal conditions, the Debye process gains significant intensity upon pressure application. This behavior contrasts with that of the previously studied octanol 2-ethyl-1-hexanol, which features a large Debye process. These experimentally observed, clearly distinguishable pressure evolutions are discussed to reflect differences in the formation of hydrogen-bonded supramolecular structures. [ABSTRACT FROM AUTHOR]

This study deals with the analysis and usefulness of the material ratio curve. The parameters obtained from this curve are presented. The most popular of these parameters include two groups that are derived from this curve and provided in the ISO 13565–2 (Rk) and ISO 13565–3 (Rq) standards. They are compared by considering their practical significance and sensitivity to measurement errors. The parameters in the Rk family can easily be calculated but are ambiguous, which leads to errors in their calculation. The Rq group, which is based more on theoretical logic, must be applied with great care because of the problems with the Rpq parameter calculation and approximation of the material ratio probability plot. The methods of obtaining the correct oil capacity and its relation with the transition point between the central and valley surface parts are presented. The application of the material ratio curve in low-wear assessment is discussed. • Relationship among surface topography, manufacturing, and function. • Parameters obtained from the material ratio curve. • Comparison of the parameters from the Rk and Rq groups. • Oil-capacity determination. • Low-wear assessment. [ABSTRACT FROM AUTHOR]

Like the skin, our hair shows striking changes with age, producing hairs with altered diameter, lustre and texture. The biology of hair aging has focused predominately on various aspects of the hair cycle, follicle size and the fibre produced, but surprisingly the impact of the aging scalp dermal environment on the hair follicle and fibre has been generally overlooked. Hair loss affects both sexes with incidence increasing with age. In men, male pattern‐balding (androgenetic alopecia) is driven by androgens and follows a specific pattern of frontotemporal and vertex regression. Women also experience female pattern hair loss (FPHL), presenting as more general, diffuse hair thinning. Hair thinning in women is commonly associated with the menopause, corresponding with other age‐related changes in skin. The rapidly growing hair follicle undergoes continued renewal throughout the life span of an individual, where it is exposed to a substantial number of extrinsic and intrinsic stressors. As the hair follicle sits deep within the dermis with its bulb residing in the hypodermis, detrimental age‐related changes in the surrounding scalp skin may likely disrupt the hair follicle machinery. The impacts of these changes are unknown, but evidence suggests that scalp skin aging and hair follicle aging go hand‐in‐hand. Herein, we summarize the evidence that the age‐related changes observed in sun‐exposed human skin also occur in scalp skin and that these changes are likely to play a contributing role in the aging hair phenotype. [ABSTRACT FROM AUTHOR]

In this paper, applying the density scaling idea to an associated liquid 4-methyl-2-pentanol used as an example, we identify different pressure-volume-temperature ranges within which molecular dynamics is dominated by either complex H-bonded networks most probably leading to supramolecular structures or non-specific intermolecular interactions like van der Waals forces. In this way, we show that the density scaling law for molecular dynamics near the glass transition provides a sensitive tool to detect thermodynamic regions characterized by intermolecular interactions of different type and complexity for a given material in the wide pressure-volume-temperature domain even if its typical form with constant scaling exponent is not obeyed. Moreover, we quantify the observed decoupling between dielectric and mechanical relaxations of the material in the density scaling regime. The suggested methods of analyses and their interpretations open new prospects for formulating models based on proper effective intermolecular potentials describing physicochemical phenomena near the glass transition. [ABSTRACT FROM AUTHOR]

Electrical impedance of bismuth manganite ceramics was studied under ambient and high hydrostatic pressure. Local disorder of crystal lattice was confirmed using XRD and DSC. Two relaxation processes were discerned. One was attributed to small polarons, which showed a changeover from variable range hopping features related to Fermi glass and structural disorder to the nearest neighbor hopping behavior in higher temperature range related to uniform distribution of energy levels. Hydrostatic pressure shortened relaxation times that would be interesting for applications. The second process, which was assigned to the nearest neighbor hopping of polarons, also exhibited a changeover to glassy features in a high‐temperature range. [ABSTRACT FROM AUTHOR]

The complex relative permittivity of a non-crystallizable secondary alcohol, 5-methyl-2-hexanol, is measured over a wide range of temperatures and pressures up to 1750 MPa (17.5 kbar). The data at atmospheric pressure (P = 0.101 MPa) are analyzed in terms of three processes, and the results are in complete agreement with that of O. E. Kalinovskaya and J. K. Vij [J. Chem. Phys. 112, 3262 (2000)]. Process I is of the Debye type and process II is of the Davidson-Cole type, whereas process III is identified as the Johari-Goldstein relaxation process. For pressures of ∼500 MPa and higher, processes I and II are seen to merge into each other to form a single dominant process which unambiguously cannot be resolved into more than one process. The dielectric relaxation strength of process I decreases slightly initially with pressure and when the two processes have merged at elevated pressures, the total relaxation strength increases with increase in pressure. Process III is better resolvable at higher pressures especially above Tg in the supercooled liquid state for the reason that the separation in the time scales between the dominant and the JG relaxation process increases at elevated pressures. Surprisingly we find a change in the slope in the plot of log τJG vs. 1/T for P = 1750 MPa. The results for the relaxation time of alcohols are compared with the Kirkwood correlation factor, g, and it is found that higher is the g, lower is the relaxation time for process I, and it is more of the Debye type. On a reduction in g brought about by an increase in pressure at lower temperatures, the dominant process becomes non-Debye though extensive hydrogen bonding is still present. The dielectric strength of the merged processes increases with increase in pressure. The values of the steepness index, m = |d log τ/d(Tg/T)|T = Tg for processes I and II are different for P = 0.1 MPa. However the value of m, for the composite process, which is a merger of processes I and II, for P = 1750 MPa is almost the same for process II at P = 0.1 MPa. From the results of the activation volume, activation enthalpy, and a comparison of the relaxation times with the g factor, we conclude that both processes I and II are significantly affected by hydrogen bonding and both contribute to the structural relaxation. [ABSTRACT FROM AUTHOR]

The molecular dynamics of hydrogen-bonded liquids usually does not satisfy the thermodynamic scaling. However, very recently, two opposite conclusions about validity of thermodynamical scaling in monohydroxy alcohol, 2-ethyl-1-hexanol, were presented by Reiser et al. [J. Chem. Phys. 132, 181101 (2010)] and Fragiadakis et al. [J. Chem. Phys. 132, 144505 (2010)]. In this communication we present new experimental results that can explain this ostensible contradiction. [ABSTRACT FROM AUTHOR]

Despite extensive efforts in experimental and computational studies,the microscopic understanding of dynamics of biologicalmacromolecules remains a great challenge. It is known that hydratedproteins, DNA and RNA, exhibit a so-called “dynamic transition.” It appears as a sharp rise of their mean-squared atomic displacements ≤r2≥ at temperatures above 200–230 K. Even after a long history of studies, this sudden activation of biomolecular dynamics remains a puzzle and many contradicting models have been proposed. By combining neutron and dielectric spectroscopy data, we were able to follow protein dynamics over an extremely broad frequency range. Our results show that there is no sudden change in the dynamics of the protein at temperatures around ∼200–230 K. The protein’s relaxation time exhibits a smooth temperature variation over the temperature range of 180–300 K. Thus the experimentally observed sharp rise in ≤r2≥ is just a result of the protein’s structural relaxation reaching the limit of the experimental frequency window. The microscopic mechanism of the protein’s structural relaxation remains unclear. [ABSTRACT FROM AUTHOR]

The primary α and the secondary Johari–Goldstein (JG) β relaxations of supercooled glass-forming neat epoxy resin and 2-picoline in mixture with tristyrene are monitored by broadband dielectric relaxation spectroscopy at ambient pressure and elevated pressures. For different combinations of pressure and temperature that maintain the α-relaxation time constant, the frequency dispersion of the α relaxation is unchanged, as previously found in other glass-formers, but remarkably the JG β-relaxation time remains constant. This is more clear evidence of a strong connection between the α- and JG β-relaxation times, a fact that should be taken into account in the construction of a viable theory of glass transition. [ABSTRACT FROM AUTHOR]

Dielectric relaxation spectra of two closely related glass formers, dipropylene glycol [H–(C3H6O)2–OH] and dipropylene glycol dimethyl ether [CH3–O–(C3H6O)2–CH3], were measured at ambient and elevated pressures in the supercooled and the glassy states are presented. Hydrogen bonds formed in dipropylene glycol are removed when its ends are replaced by two methyl groups to become dipropylene glycol dimethyl ether. In the process, the primary relaxation, the excess wing, and the resolved secondary relaxation of dipropylene glycol are all modified when the structure is transformed to become dipropylene glycol dimethyl ether. The modifications include the pressure and temperature dependences of these relaxation processes and their interrelations. Thus, by comparing the dielectric spectra of these two closely related glass formers at ambient and elevated pressures, the differences in the relaxation dynamics and properties in the presence and absence of hydrogen bonding are identified. [ABSTRACT FROM AUTHOR]

A combined positronium annihilation lifetime spectroscopy (PALS) and dielectric spectroscopy (DS) study on a typical van der Waals glass-former diethyl phthalate (DEP) was performed and the results were compared. From phenomenological point of view, the mutual relationships between the characteristic PALS temperatures, the glass temperature TgPALS, and the crossover temperatures Tb1L and Tb2L on the ortho-positronium (o-Ps) lifetime versus the temperature plot, have been discussed with respect to the characteristic DS temperatures, the glass temperature TgDS and the dynamic crossover temperature TBST, concerning the crossover behavior of primary α-relaxation times. Next, simultaneous application of the extended free volume (EFV) model by Cohen-Grest on the temperature dependence of both the mean free volume hole size data as extracted from PALS and the dielectric α-relaxation time revealed a good agreement between the experimental Tb1L and the characteristic EFV temperatures T0DS and T0PALS at which a free volume percolation should occur. These results indicate the important role of free volume in control of the primary (α) dynamics of supercooled DEP. [ABSTRACT FROM AUTHOR]

Wear leads to loss of functions of machines and to a decrease in their efficiencies. Controlling wear through wear resistance tests is a very important task. Wear tests aim to obtain wear levels of the elements of assemblies in contact. The profilometric method is very helpful. In this paper, measurements of wear scars using the profilometric method are reviewed. Volumetric wear determinations in various configurations, including ball-on-disc tests, block-on-ring tests, reciprocating ball-on-plate tests, and scratch tests were studied. The measurement of the volumetric wear of balls or rounded pins was also analysed. Possible errors in wear levels determinations were discussed. Limitations of profiloemtric measurement methods were considered. • The best practice is to perform a complete areal surface measurement of wear scar. • The profilometric measurement of wear scar is subjected to errors. • Areal surface measurement of wear scar leads to more precise results than approximate methods. • Existing standards related to wear scar measurements should be modified. [ABSTRACT FROM AUTHOR]

Accurate wear measurement is an important task. In this paper, measurements of wear levels within the limits of the original surface topography using profilometric methods were presented and discussed. The relocation methods, allowing measurements of surface fragments in the same place prior and after tests, were presented. Profilometric methodologies without sample relocation were discussed. Methods of quantitative wear assessment were shown. Qualitative wear characterisations were studied. Future trends in low-wear profilometric measurement were discussed. • To measure surface before and after wear, precise surface relocation is needed. • The wear level can be estimated based on changes in parameters describing maximum surface height. • Methods of assessing low wear are usually related to the material ratio curve. • Low wear measurement is sensitive to measurement errors. [ABSTRACT FROM AUTHOR]

Broadband dielectric measurements were carried out at isobaric and isothermal conditions up to 1.75 GPa for reconsidering the relaxation dynamics of decahydroisoquinoline, previously investigated by Richert et al. [R. Richert, K. Duvvuri, and L.-T. Duong, J. Chem. Phys. 118, 1828 (2003)] at atmospheric pressure. The relaxation time of the intense secondary relaxation τβ seems to be insensitive to applied pressure, contrary to the α-relaxation times τα. Moreover, the separation of the α- and β-relaxation times lacks correlation between shapes of the α-process and β-relaxation times, predicted by the coupling model [see for example, K. L. Ngai, J. Phys.: Condens. Matter 15, S1107 (2003)], suggesting that the β process is not a true Johari–Goldstein (JG) relaxation. From the other side, by performing measurements under favorable conditions, we are able to reveal a new secondary relaxation process, otherwise suppressed by the intense β process, and to determine the temperature dependence of its relaxation times, which is in agreement with that of the JG relaxation. [ABSTRACT FROM AUTHOR]

Applications of morphological filters for two-process profiles were analysed. Dilation, closing and alternating sequential (closing + opening) filters were used with a circle (disk) as a structuring element. An original method of a disk radius selection was elaborated for two-process profiles. This procedure was applied for many simulated and measured profiles. Behaviors of morphological filters were compared with those of double Gaussian (Rk) filter. Robust filter was also taken into consideration. In calculation, TalyMap software was used. The proposed procedure was found to be very useful. It was developed for 2D profiles but it can be easily extended for an areal (3D) surface topography filtering. From among morphological filters, the alternate sequential filter is suggested. [ABSTRACT FROM AUTHOR]

The paper presents the response of a three-layered annular plate with damaged laminated facings to the loads acting in their planes. The presented problem concerns the analysis of the combination of global plate failure in the form of buckling with the local micro defects, like fibre or matrix cracks, located in the laminas. The plate structure consists of thin laminated, fibre-reinforced composite facings and a thicker foam core. The matrix and fibre cracks of facings laminas can be transversally symmetrically or asymmetrically located in plate structure. Critical static and dynamic stability analyses were carried out solving the problem numerically and analytically. The numerical results show the static and dynamic stability state of the composite plate with different combinations of damages. The final results are compared with those for undamaged structure of the plate and treated as quasi-isotropic ones. The analysed problem makes it possible to evaluate the use of the non-ideal composite plate structure in practical applications. [ABSTRACT FROM AUTHOR]

Highlights • The application of the original ISO procedure can cause overestimation of the Rpq parameter. • Two methods of an error reduction are proposed and were found to be very useful. • Errors can be diminished by the modification of the lower plateau limit by dividing the γ angle twofold or threefold. • The other procedure consists of connecting plateau portions and calculation of the Rq parameter from obtained profile. Abstract The standard deviation of the plateau height Rpq is a very important tribological parameter. However, the serious errors of its determination are possible when original procedure included in the ISO 13565-3 standard is used, because details from the valley region can be included in the plateau profile portion. Due to this error, the standard deviation of the plateau height can be overestimated. Two ways to improve the Rpq parameter calculations are proposed. The first of them depends on a modification of the procedure from the standard, while the second one recognises the starting and the finishing point of each plateau portion in a two-process profile. [ABSTRACT FROM AUTHOR]

A reduction in frictional loss is an important aspect of efficiency in high-performance internal combustion engines. This can be achieved by the well-designed surface texturing of the cylinder bore, which can reduce friction at the ring/bore interface. In this work, dimples were created using plastic deformation on the cylinder surfaces of high-performance motorcycle engines. Prior to texturing, these cylinders had Nikasil coating. One cylinder was subjected to the deposition of DLC coating and then surface texturing. The results of the functional performance of internal combustion engines with textured cylinder surfaces were compared to untextured ones. The engine performance was analysed in terms of maximum power and maximum torque output. The results showed that cylinder surface texturing improved the functional properties of internal combustion engines. The maximum power increased by up to 5.8%. Best performance was achieved for internal combustion engines with textured cylinders and DLC coating. Such surface modification allows the powering of the motorbike with higher maximum speed and provides better vehicle dynamics at high speeds. [ABSTRACT FROM AUTHOR]

This paper presents the results of the tribological experiments conducted using an oscillating wear tester under lubricated conditions. Specimen from piston ring slid against counter-specimen from cylinder liner. Various surface textures of cylinder liners resulted from honing and/or plateau honing. Tests were carried out for two normal loads of 100 and 300 N at a temperature of 80 °C, the stroke was 3 mm, the frequency was 10 Hz. Each experiment was divided into four time intervals. During breaks between the particular parts of the test, the surface topography of cylinder liners was measured by a white light interferometer. It was found that an increase in the normal load led to an increase in changes of the liner surface textures. [ABSTRACT FROM AUTHOR]

Surface texture can affect corrosion resistance, wear resistance, and contact stiffness. Modelling and prediction of textures after abrasive machining processes are useful in describing the quality of machined surfaces, leading to reduction in the production cost. In this paper, methods of modelling surface textures created by abrasive processes are critically reviewed. The modelling procedures take into account methods of surface creation. The models can be divided into physical process models based on machining theory and empirical models based on experimental design, or artificial intelligence. This paper is focused on physical process models. Special attention is paid to grinding, honing and polishing processes, but other treatments are considered. The state-of-the-art and future research directions are recognised. Although new numerical models allow one to generate areal surface topography, typically only amplitude parameters of modelled and measured textures are compared. Modelling methods should be validated on a larger number of surface texture parameters. Modelled and measured surfaces should be compared based on differences between their ordinates. [ABSTRACT FROM AUTHOR]

The results of surface texture measurements obtained with the stylus equipment, white light interferometer and confocal profilometer of the same samples were compared. Machined isotropic and anisotropic surfaces, of symmetric and asymmetric ordinate distribution were measured. Forms were removed using polynomials. Sampling intervals and measuring areas during computations of parameters were the same. Discrepancies between the results obtained with various methods were observed and discussed. It was found that errors of surface texture measurement with the optical methods depend on the type of surface topography. [ABSTRACT FROM AUTHOR]

The experiments were carried out using an Optimol SRV5 oscillating wear tester under lubrication. Specimens were cut from gray cast iron cylinder liners honed and/or plateau honed with diamond or ceramic stones. Counter-specimens were cut from chromium-coated compression ring. Short time tests of 30 min duration were conducted at a temperature of −20 °C, with a stroke of 3 mm. In addition, for a few sliding assemblies, durations of tests at the low temperature were extended to 24 h. For comparison, similar tests for a smaller number of sliding pairs were carried out at a temperature of 80 °C. Before and after tests cylinder liner surface topographies were measured by a white light interferometer Talysurf CCI Lite. It was found that the changes of liner height and frictional resistance at the low temperature were smaller from those tested at the elevated temperature. Two-process textures tested at the low temperature led to a smaller final coefficient of friction, compared to one-process surfaces; opposed results were obtained at the high temperature. [ABSTRACT FROM AUTHOR]

The paper presents the dynamic behaviour of three-layer annular plates with damaged facings. The plate is composed of thin laminated, fibre-reinforced composite facings and thicker, foam core. Failure of the plate facings is modelled as fibre or matrix cracks. The plate loaded in the plane of facings with quickly increasing radially compressed forces loses its dynamic stability. Evaluation of the critical state of the plate with failures was carried out using both analytical and numerical solutions. The comparison of results between plates with material properties treated as isotropic, quasi-isotropic and composite has been conducted. Presented tables and figures create the image of dynamic responses of examined composite plates with structure failures. [ABSTRACT FROM AUTHOR]

The new vibrational and computational studies on bis(2-aminopiridinium) fumarate -- fumaric acid (1:1) complex have been made. The molecular geometry, vibrational frequencies and intensities of vibrational bands have been interpreted with the aid of structure optimization based on density functional theory (B3LYP) method with 6-311++G(d,p) basis set. The highly occupied-lowly unoccupied molecular orbital energies and chemical reactivity of the molecule have been calculated with time-dependent density functional theory approach. Stability energies of the molecule have been studied using natural bond orbital analysis. The predicted nonlinear optical properties of the title compound are much greater that those of urea. In addition, the molecular electrostatic potential surfaces and thermodynamic properties were calculated. [ABSTRACT FROM AUTHOR]

The paper presents the dynamic response of annular three-layered plate subjected to loads variable in time. The plate is loaded in the plane of outer layers. The plate core has the electrorheological properties expressed by the Bingham body model. The dynamic stability loss of plate with elastic core is determined by the critical state parameters, particularly by the critical stresses. Numerous numerical observations show the influence of the values of viscosity constant and critical shear stresses, being the Bingham body parameters, on the supercritical viscous fluid plate behaviour. The problem has been solved analytically and numerically using the orthogonalization method and finite difference method. The solution includes both axisymmetric and asymmetric plate dynamic modes. [ABSTRACT FROM AUTHOR]

The (1 − x )Pb(Zr 0.70 Ti 0.30 )O 3 – x BiMn 2 O 5 ceramics (PZT-BM), where x = 0, 0.02, 0.055, 0.11, 0.15, 0.22 and 1, were studied. We determined how addition of nonpolar BM influenced electrical properties of the ferroelectric PZT ceramics. Impedance spectroscopy measurements in broad frequency and temperature ranges were performed and several contributions to impedance response were identified. A crossover to the relaxor state was observed in the PZT-BM ceramics by doping with Bi and Mn ions. The relaxation times for the electric conductivity relaxation and dipole relaxation were estimated from electric modulus representation of the data. Activation energy values of the conductivity process, estimated for T > 510 K, decreased from 0.82 to 0.37 eV when BM content increased. The occurrence of the high-frequency dipole relaxation was assigned to the charge transfer of Ti 3+ /Ti 4+ , Zr 3+ /Zr 4+ and Mn 3+ /Mn 4+ ions. Occurrence of the ferroelectric relaxor features were deduced from the non-Arrhenius dependence of the relaxation times. Superposition of the relaxor features and electric relaxations provides high value permittivity (ε′ > 1000) in wide temperature range (~ 250–573 K). This effect corresponds to the disorder and precipitation of ions that were shown using x-ray photoelectron spectroscopy and the time of flight–secondary ion mass spectrometry. [ABSTRACT FROM AUTHOR]

The experiments were conducted using an oscillating wear tester under lubricated conditions. Specimens were cut from cylinder liners made of gray cast iron. As the results of honing and/or plateau honing various surface textures of cylinder liners were obtained. Counter-specimens were cut from chromium-coated compression ring. Short time tests were carried out at temperature of 80 °C, stroke was 3 mm. The other operating parameters, like normal load and frequency varied. Before and after tests surface topographies of liners were measured by a white light interferometer. It was found that one-process textures led to smaller coefficients of friction than two-process topographies for test duration of 0.5 h. The frictional resistance increased when honing angle increased. [ABSTRACT FROM AUTHOR]

The ability of an electric powertrain to perform according to mechanical specifications is equally important as assessing its thermal protection limits, which are affected by its electrical and thermal properties. Although rated parameters (such as power, torque, etc.) are easily accessible in catalogs of equipment producers, more specific properties like mass/length of copper winding, heat dissipation factor, etc., are not available to customers. Therefore, an effective selection of drivetrain components is limited due to the lack of sufficient data and the need to consult critical design decisions with suppliers. To overcome this limitation, we propose a method to estimate the temperature rise of motor drives based on popular loadability curves, which are provided in catalogs. A simple first-order thermal model is applied to represent heating/cooling phenomenon of motor drives. The parameters’ identification process is formulated as a nonlinear optimization problem and solved using commercial software products. Within the proposed approach, it becomes possible to include the effect of reduced torque availability at low speeds in self-ventilated motors during design of electric actuation systems. Contrary to using a discrete set of permissible overload conditions from the catalogs, the current methodology allows for evaluating a temperature rise of a motor drive for any overload magnitude, duty cycle, and ambient temperature. This greatly improves flexibility of the design process and facilitates communication in a supplier–customer dialog. The discussed method is verified against reference overload recommendations, yielding the same thermal protection levels, and validated using the experimental results, producing identical motor temperature rise profiles as the ones measured on the laboratory test bench. [ABSTRACT FROM AUTHOR]

This work is focused on the issue of non-measured points - one of the most important problems in surface texture measurements using optical methods. The fundamental aim of this research is to analyse errors of surface texture measurements caused by the presence of non-measured points. This study is divided into two parts. In the first part, circles with non-measured points were artificially created on peak portions of measured surfaces. In the second part - the results of measurement by a Talysurf CCI Lite interferometer were analysed. A measurement area of 3.3 × 3.3 mm contained 1024 × 1024 points. The measurements were performed with different intensity of light. Changes of parameters regarding the analysed errors depended on a surface type. The following parameters are susceptible to errors: skewness Ssk, areal material ratio Smr, as well as the following feature parameters: Spd, Sda, Sdv, Sha and Shv. Inaccuracies of measurement in valley parts of two-process textures led usually to larger errors of parameter computations compared with deviations in peak portions. [ABSTRACT FROM AUTHOR]

This paper describes the tribological influence of surface topography on friction and wear under dry fretting gross slip regime in a point contact. Experiments were made using ball-on-disc tribotester in oscillatory motion. 100Cr6 sphere co-acted with a disc made of 42CrMo4 steel. During tests, the friction force was monitored as a function of time. Wear of discs and balls was measured after the tests using white light interferometer. Disc surfaces were prepared by various techniques, including milling, vapour blasting, polishing, lapping and grinding. Initial surface roughness height of discs, determined by the Sq parameter was in the range: 0.01–9 μm. During tests, normal load was kept constant at 45 N within the contact with frequency of 20 Hz. Tests were carried out with different displacement amplitudes: 0.02, 0.05 and 0.075 mm. It was found that initial surface roughness height had a significant influence on friction and wear. [ABSTRACT FROM AUTHOR]