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Copper-graphite composites of different compositions sliding against copper are investigated with regards to friction, wear and contact resistance. We find that comprehensive studies including the tribological as well as electrical aspects are rarely found in the literature. We combine friction, wear and contact resistance measurements with thorough surface analysis to complete the understanding. We find that including graphite in the composite greatly reduce the coefficient of friction. However, increasing the vol.% of graphite above 74 will not continue to reduce the friction. We conclude that the coefficient of friction is slightly lower when testing is performed without current than at 5 A current. A comparison of the specific wear rate for the tested composites shows that the one with 74 vol.% of graphite gives the lowest wear rate. In general, the wear rate is higher when tests are performed without current. Chemical analysis of the tribofilm that forms on the copper surface shows that it consists of graphite as well as Cu2O. It is also shown that the amount of graphite in the tribofilm correlates to the composition of the copper-graphite. Novel cross-section images of the tribofilm contribute to a deeper understanding of how sliding electrical contact surfaces are affected by current and sliding motion.

Background and Aims: Significant stenosis is the principal cause of stable angina but its predictors and their variation by geographical region are unclear. Methods and Results: From the European Calcific Coronary Artery Disease (Euro-CCAD) cohort, we retrospectively investigated 5515 symptomatic patients from northern Europe (Denmark, France, Germany), southern Europe (Italy, Spain) and USA. All had conventional cardiovascular risk factor assessment, angiography and CT scanning for coronary artery calcium (CAC) scoring. There were differences in the patient characteristics between the groups, with the USA patients being younger and having more diet and lifestyle-related risk factors, although hypertension may have been better controlled than in Europe. USA patients had a two-fold increase in prevalence of significant stenosis and a three-fold increase in median CAC score. In all three groups, the log CAC score proved to be the strongest predictor of >50% stenosis followed by male gender. In the USA group, there were no additional independently predictive risk factors, although in northern Europe obesity, hypertension, smoking and hypercholesterolaemia remained predictive, with all risk factors other than hypertension proving to be predictive in the southern Europe group. Without the CAC score as a variable, male gender followed by diabetes were the most important predictors in all three regions, with hypertension also proving predictive in northern Europe. Conclusion: In symptomatic patients, the CAC score and male gender were the two most important predictors of significant stenosis in symptomatic patients in northern and southern Europe and the USA.

In order to facilitate data-driven solutions for early detection of atrial fibrillation (AF), the 2017 CinC conference challenge was devoted to automatic AF classification based on short ECG recordings. The proposed solutions concentrated on maximizing the classifiers F-1 score, whereas the complexity of the classifiers was not considered. However, we argue that this must be addressed as complexity places restrictions on the applicability of inexpensive devices for AF monitoring outside hospitals. Therefore, this study investigates the feasibility of complexity reduction by analyzing one of the solutions presented for the challenge.

Background: The heart rate (HR) response to paced deep breathing (DB) is a common test of cardiac autonomic function, where high heart rate variability (HRV) is considered to reflect normal autonomic function. We evaluated the DB test in patients with hereditary transthyretin amyloid (ATTRm) amyloidosis, where autonomic dysregulation and atrial arrhythmias are common.Methods: Paced DB was performed during one minute (six breaths/min) in 165 recordings in adult ATTRm amyloidosis patients with the TTR Val30Met mutation, 42 hypertrophic cardiomyopathy (HCM) patients and 211 healthy subjects. HRV was scored by traditional DB indices and by a novel regularity index, estimating the fraction of the HRV that was coherent with the breathing pattern.Results: Twenty per cent of ATTRm amyloidosis patients presented with age-adjusted HRV scores within normal limits but poor regularity due to subtle atrial arrhythmias and cardiac conduction disturbances. Forty-seven per cent of ATTRm amyloidosis patients presented with HRV scores below normal limits, whereas HCM patients presented with higher HRV than ATTRm amyloidosis patients.Conclusions: Reduced HRV is common in ATTRm amyloidosis patients during DB, however, autonomic function cannot be evaluated in patients presenting with the combination of normal scores and low regularity, since their HR responses often reflects dysrhythmias.

Background: Many telehealth (TH) systems have been designed to identify signs of COPD exacerbations, but few previous studies have reported the nature of recorded lung function data and what variations to expect in stable versus unstable patients. Aims: To evaluate the nature of individual diurnal, day-to-day and long-term variation in important prognostic markers of COPD exacerbations in a heterogeneous patient group by employing a newly developed TH system. Methods: Eight women and five men with COPD performed measurements (FEV1, IC, SpO2 and CAT) three times per week during 4-6 months using the TH system. Feasibility was based on the repeatability and quality of the FEV1 and IC measurements, as defined by ERS/ATS guidelines. Short-term and long-term individual variations were assessed using the relative density and mean (SD) respectively. Results: Close to 1100 FEV1 and IC measurements respectively were performed during a total of 240 patient weeks. The 2SD ranges for intra-individual variation were ± 210 mL and ± 350 mL for FEV1 and IC respectively. The values both increased and decreased without corresponding influence on symptoms (CAT) or SpO2 and no exacerbation was reported. However, it was unusual with a decrease of more than 50 mL per measurement in FEV1 between three consecutive measurement days. Conclusions: This study reveals important and, to our knowledge, previously not reported information about short and long-term variability in lung function measurements in stable patients with COPD, of significance when defining criteria for detecting exacerbations with TH systems.

Objective: Novel minimum-contact vital signs monitoring techniques like textile or capacitive electrocardiogram (ECG) provide new opportunities for health monitoring. These techniques are sensitive to artifacts and require handling of unstable signal quality. Spatio-temporal blind source separation (BSS) is capable of processing suchlike multichannel signals. However, BSS's permutation indeterminacy requires the selection of the cardiac signal (i.e., the component resembling the electric cardiac activity) after its separation from artifacts. This study evaluates different concepts for solving permutation indeterminacy. Methods: Novel automated component selection routines based on heartbeat detections are compared with standard concepts, as using higher order moments or frequency-domain features, for solving permutation indeterminacy in spatio-temporal BSS. BSS was applied to a textile and a capacitive ECG dataset of healthy subjects performing a motion protocol, and to the MIT-BIH Arrhythmia Database. The performance of the subsequent component selection was evaluated by means of the heartbeat detection accuracy (ACC) using an automatically selected single component. Results: The proposed heartbeat-detection-based selection routines significantly outperformed the standard selectors based on Skewness, Kurtosis, and frequency-domain features, especially for datasets containing motion artifacts. For arrhythmia data, beat analysis by sparse coding outperformed simple periodicity tests of the detected heartbeats. Conclusion: Component selection routines based on heartbeat detections are capable of reliably selecting cardiac signals after spatio-temporal BSS in case of severe motion artifacts and arrhythmia. Significance: The availability of robust cardiac component selectors for solving permutation indeterminacy facilitates the usage of spatio-temporal BSS to extract cardiac signals in artifact-sensitive minimum-contact vital signs monitoring techniques.

The heart rate (HR) response to paced deep breathing (DB) is a common test of autonomic function, where the scoring is based on indices reflecting the overall heart rate variability (HRV), where high scores are considered as normal findings but can also reflect arrhythmias. This study presents a method based on hyperdimensional computing for assessment of the similarity between feature vectors derived from the HR and breathing signals. The proposed method was used to identify subjects where HR did not follow the paced breathing pattern in recordings from DB tests in 174 healthy subjects and 135 patients with cardiac autonomic neuropathy. Subjects were classified in 4 similarity classes, where the lowest similiarity class included 35 patients and 3 controls. In general, the autonomic function cannot be evaluated in subjects in the lowest similarity class if they also present with high HRV scores, since this combination is a strong indicator of the presence of arrhythmias. Thus, the proposed vector-based similarity analysis is one tool to identify subjects with high HRV but low cardiorespiratory synchronization during the DB test, which falsely can be interpreted as normal autonomic function.

Top hammer rock drill bits are equipped with cemented carbide inserts. These inserts consist of WC and ~6w% Co binder. Due to the recent classification of Co as a probable carcinogen upon inhalation there is a need to substitute Co. Thus, in the present work the wear of Co, Ni and Fe based cemented carbides are compared in a wear test that mimics the wear surface in real drilling conditions. The inserts are tested against counter surfaces of granite and sandstone using deionised water and synthetic mine water as flushing agents. This with the aim to study the tribo-chemical nature of the wear as well as the impact of different stones. To the authors’ knowledge, the impact of the chemical environment on cemented carbide degradation in a wear test that imitates the field wear scars in rock drilling is not yet known. The work focuses on studying the wear rate differences between the different cemented carbides and test conditions and includes a study of the worn surfaces using SEM and EDS.

A common type of rock drill bits is a steel head studded with cemented carbide buttons. The function of the steel is mainly to hold the buttons in place while the buttons do most of the rock crushing. However, a significant amount of wear also occurs on the steel matrix so also this material must provide adequate wear resistance. Flushing media is provided to the drilling zone. Preferably, the water is fresh water but in certain geographical areas supply of fresh water is scarce. Bringing fresh water in such areas is costly and sea water or mine water can be used instead. This will expose the equipment, and the drill bit in particular, to more or less corrosive media and possibly change the wear mechanisms of the tool. In this four drill bit matrix steels were tested in a lab scale test simulating the rock drilling including supply of cuttings. During the test the contact zone between the button and the rock was flushed with either fresh water or salty water. The wear rate was measured and the wear scar was studied using SEM and EDS to show the influence of salinity on matrix steel wear.

Additive manufacturing is an emerging technique for producing near-net-shape components. It is especially interesting for producing components in materials that are difficult to machine or components made of materials that are difficult or impossible to produce with conventional techniques. Recently, a family of hard wear resistant steel materials, suitable for heavily loaded components or even tools, have been developed for AM production by the company VBN Components. This work reports on the evaluation of the mechanical properties and abrasive wear resistance of such materials. Three body abrasive testing was employed using particles of aluminium oxide and diamond. The results are compared to conventionally produced materials. The worn surfaces were also studied in SEM to discern differences in wear mechanisms related to the specific AM microstructure.

Powder bed additive manufacturing (AM) is a method for producing near-net-shape components by selectively melting metal powder where material is desired, layer by later. This is directly contrary to conventional machining being a solely subtractive process where material is removed from a large work piece. It is well known that AM often results in microstructural anisotropy related to the build direction. In the case of Inconel 718, columnar grains are formed, oriented along the build direction. Furthermore, utilizing different scan strategies such as contouring will result in different grain structures in the near surface region compared to the bulk of the material. The aim of this work was to study the effects of these microstructural anisotropies on the mechanical and tribological properties. Cylindrical test specimens with were built with different build directions and scan strategies and mechanically characterized and tested in a rolling contact fatigue test rig where a specimen was placed between two hard rollers. As the very surface presents a rough topography comprised of partly melted powder particles which hinders any tribological function of the component the samples were grinded prior to the rolling contact fatigue tests. After testing, the contact tracks were analyzed using, SEM and EBSD.

The combination of metal thin coating with polymer films have been studied extensively in e.g. the field of food packing, medical and aerospace application. In such applications the mechanical performance and structural integrity of the coated films are frequently of interest. Depending on the purpose of the coating, there are various characterization methods, for example the peel test, scratch test, indentation test, fragmentation test as well as simulation methods to predict the mechanical performance based on material properties identified by such tests. The first and perhaps most common parameter to characterize is the stiffness of the coating and substrate, which are important input parameters in predictive finite element simulations of failure of brittle coatings, affecting the barrier function. The relatively thick polymer films can be characterized by conventional tensile testing. However, stiffness characterization for the ultrathin coating (nanometer scale) is much more challenging. In this research, three independent experimental test modes have been used to estimate the thickness of thin brittle coatings. The various methods are complementary with different advantages and drawbacks. They are based on (i) Nanoindentation, (ii) strain induced elastic buckling instability, and (iii) AFM peak force measurements. The samples were prepared by atomic layer deposition in 4 types of coating: TiO2 (titanium oxide) of 20 and 6 nm thick and MOX (mixed oxide, TiO2 and Al2O3) of 20 and 4 nm thick. The differences in estimated Young’s moduli are interpreted in terms of the underlying assumptions and test conditions. Their specific advantages and drawbacks are also compared and discussed.

A nanosectioning (cutting) method was used to test the local shear yield stress and fracture toughness (specific work of surface formation) of multiwall carbon nanotube (MWCNT) poly(methyl methacrylate) (PMMA) composites, and the effects of MWCNT content on the yield stress and toughness were investigated. The composites were prepared by a solution casting method, with MWCNT content varying from 0.05 to 1.0 wt%. Above 0.1 wt% MWCNT content, the yield stress reduced by the addition of MWCNTs. The fracture toughness of the composite was effectively enhanced by the addition of MWCNTs, ranging from 17 J/m2 for the neat PMMA to 25 J/m2 for the 1.0 wt% composite. The shear yield stresses obtained by nanosectioning were correlated to nanoindentation measurement, and possible contributions from the MWCNTs to the fracture toughness of the composite were analysed.

Material transferred from steel work materials onto the cutting tools largely affects tool life and machining performance. This material transfer is strongly influenced by the steel composition, and different alloying can have very different effects. Crossed cylinders sliding tests can be used to simulate the contact between the chip and the tool in machining. In this work such a test is used to evaluate material transfer and friction characteristics of a TiN coated tool sliding against five model steels. These model steels are especially designed to study the effects from specific combination of alloy elements, i.e. the steels, containing 0.55 mass% C and 1 mass% Si, are alloyed with one or more of 1 mass% Mn, Cr and Al. When using the steels alloyed without Al, Si-rich oxide layers are formed on the coating, resulting in a low friction coefficient. When using the steels alloyed with Al, almost pure Al–O layers are formed, resulting in a higher friction coefficient and rapid coating cracking. Essentially, the most easily oxidized alloy element is most strongly enriched in the oxide and decides the main mechanism of the material transfer and friction behavior.

Suspension plasma spray is a relatively new thermal spray technique which enables feeding of fine powder to produce advanced coatings for varied applications. This work investigates the difference in structure and performance of Al2O3 coatings manufactured using conventional micron-sized powder feedstock and a suspension of sub-micron to few micron sized powder. Axial injection was implemented for deposition in both cases. The effect of feedstock size and processing on the tribological performance of the two coatings was of specific interest. The coatings were characterized by Optical and Scanning Electron Microscopy, micro-hardness and scratch resistance testing, and their dry sliding wear performance evaluated. The suspension sprayed coatings yielded significantly higher scratch resistance, lower friction coefficient and reduced wear rate compared to conventional coatings. The improved tribological behaviour of the former is attributable to finer porosity, smaller splat sizes, and improved interlamellar bonding.

Aims: To evaluate the role of the autonomic nervous system (ANS) in the development of insulin resistance (IR) and assess the relationship between IR and activity of ANS using power spectrum analysis of heart rate variability (HRV). Subjects and methods: Twenty-three healthy first-degree relatives of patients with type 2 diabetes (R) and 24 control subjects without family history of diabetes (C) group-matched for age, BMI and sex were included. Insulin sensitivity (M value) was assessed by hyperinsulinemic (56 mU/m2/min) euglycemic clamp. Activity of the ANS was assessed using power spectrum analysis of HRV in long-term recordings, i.e., 24-h ECG monitoring, and in short-term recordings during manoeuvres activating the ANS. Computed tomography was performed to estimate the amount and distribution of abdominal adipose tissue. Results: Insulin sensitivity (M value, mg/kg lbm/min) did not differ significantly between the R and C groups. Total spectral power (Ptot) and very low-frequency (PVLF) power was lower in R than C during 24 h ECG-recordings (p = 0.02 and p = 0.03). The best fit multiple variable linear regression model (r2 = 0.37, p < 0.001 for model) indicated that body composition (BMI) and long-term low to high frequency (LF/HF) power ratio (std β = −0.46, p = 0.001 and std β = −0.28, p = 0.003, respectively) were significantly and independently associated with the M value. Conclusion: Altered heart rate variability, assessed by power spectrum analysis, during everyday life is linked to insulin resistance. The data suggest that an increased ratio of sympathetic to parasympathetic nerve activity, occurring via both inherited and acquired mechanisms, could potentially contribute to the development of type 2 diabetes.

Sliding between crossed cylinders, one large work material cylinder and one smaller coated tool cylinder, can be used to simulate the contact between a chip and the rake face of a cutting tool. However accurate simulations require the mode of material transfer in the test to match that in real machining. The mode is strongly dependent on normal load and sliding speed, and it is classified into four types; negligible oxide, only iron oxide, iron oxide and alloy oxide, and metallic transfer with coating cracking. A high load proved to be most important to accurately simulate the mode and area of material transfer occurring in milling. The diameter of the work material cylinder influences the shape of the contact mark, but has no influence on the mode of transfer. This means smaller work material diameters can favorably be used, reducing costs and facilitating handling during both tests and analysis.

To understand how the energy requirements of the mechanical pulping process can be reduced, the fundamental mechanisms behind fiber separation in Norway spruce were studied experimentally and analytically. Single tip scratching in heated water was used to reproduce initial defibration mechanisms found industrially. The resulting scratches were then compared with surfaces ground in a real industrial process. Moreover, the mechanical behavior of the wood microstructure was monitored with X-ray computed microtomography as a single hard tip was pressed into it. Subsequent digital image correlation was applied to estimate the strain field in the region around the indenting tip. Regions in the wood with high tensile or shear strains were identified, i.e. where cracking and fiber separation is believed to initiate.

A crossed cylinders sliding test, simulating the contact between the chip and the cutting tool, is used to evaluate material transfer, friction characteristics and coating damage of a TiN coated high speed steel against specifically designed model steels. These steels include one reference with C as the only alloy element (Base steel), and two alloyed also with 1 mass% Mn or Al. When sliding against the Base steel, an Fe–O layer forms on the coating and protects it from wear. Against the Mn alloyed steel, Fe–Mn–O forms, which has no protective effect. Against the Al alloyed steel, an almost pure Al–O layer forms. This leads to the highest friction, rapidly causing substrate softening and coating fracture.

Wearable sensor technology like textile electrodes provides novel ambulatory health monitoring solutions but most often goes along with low signal quality. Blind Source Separation (BSS) is capable of extracting the Electrocardiogram (ECG) out of heavily distorted multichannel recordings. However, permutation indeterminacy has to be solved, i.e. the automated selection of the desired BSS output. To that end we propose to exploit the sparsity of the ECG modeled as a spike train of successive heartbeats. A binary code derived from a two-item dictionary {peak, no peak} and physiological a-priori information temporally represents every BSS output component. The (best) ECG component is automatically selected based on a modified Hamming distance comparing the components' code with the expected code behavior. Non-standard ECG recordings from ten healthy subjects performing common motions while wearing a sensor garment were subsequently processed in 10 s segments with spatio-temporal BSS. Our sparsity-based selection RCODE achieved 98.1% heart beat detection accuracy (ACC) by selecting a single component each after BSS. Traditional component selection based on higher-order statistics (e.g. skewness) achieved only 67.6% ACC.

Gastric bypass (GBP) surgery, one of the most common bariatric procedures, induces weight loss and metabolic effects. The mechanisms are not fully understood, but reduced food intake and effects on gastrointestinal hormones are thought to contribute. We recently observed that GBP patients have lowered glucose levels and frequent asymptomatic hypoglycemic episodes. Here, we subjected patients before and after undergoing GBP surgery to hypoglycemia and examined symptoms and hormonal and autonomic nerve responses. Twelve obese patients without diabetes (8 women, mean age 43.1 years [SD 10.8] and BMI 40.6 kg/m(2) [SD 3.1]) were examined before and 23 weeks (range 19-25) after GBP surgery with hyperinsulinemic-hypoglycemic clamp (stepwise to plasma glucose 2.7 mmol/L). The mean change in Edinburgh Hypoglycemia Score during clamp was attenuated from 10.7 (6.4) before surgery to 5.2 (4.9) after surgery. There were also marked postsurgery reductions in levels of glucagon, cortisol, and catecholamine and the sympathetic nerve responses to hypoglycemia. In addition, growth hormone displayed a delayed response but to a higher peak level. Levels of glucagon-like peptide 1 and gastric inhibitory polypeptide rose during hypoglycemia but rose less postsurgery compared with presurgery. Thus, GBP surgery causes a resetting of glucose homeostasis, which reduces symptoms and neurohormonal responses to hypoglycemia. Further studies should address the underlying mechanisms as well as their impact on the overall metabolic effects of GBP surgery.

A crossed cylinders sliding test, simulating the contact between the chip and the tool in machining, is used to evaluate material transfer and friction characteristics of a TiN coating against specifically designed model steels. These include one base reference, only alloyed with C (Base steel) and two alloyed also with 1 mass% Si or Cr. When sliding against the Base steel, an Fe-O layer is formed on the coating. Against the Si and Cr alloyed steels, Fe-Si-O and Fe-Cr-O layers are formed. In these oxides, Si and Cr are enriched, i.e. preferentially transferred from the steels. Compared to the Base steel, the friction coefficient is significantly lower against the Si alloyed steel and higher against the Cr alloyed steel.

Aims: In this retrospective study we assessed the predictive value of the coronary calcium score for significant (>50%) stenosis relative to conventional risk factors. Methods and Results: We investigated 5515 symptomatic patients from Denmark, France, Germany, Italy, Spain and the USA. All had risk factor assessment, computed tomographic coronary angiogram (CTCA) or conventional angiography and a CT scan for coronary artery calcium (CAC) scoring. 1539 (27.9%) patients had significant stenosis, 5.50 of whom had zero CAC. In 5074 patients, multiple binary regression showed the most important predictor of significant stenosis to be male gender (B = 1.07) followed by diabetes mellitus (B = 0.70) smoking, hypercholesterolaemia, hypertension, family history of CAD and age but not obesity. When the log transformed CAC score was included, it became the most powerful predictor (B = 1.25), followed by male gender (B = 0.48), diabetes, smoking, family history and age but hypercholesterolaemia and hypertension lost significance. The CAC score is a more accurate predictor of >50% stenosis than risk factors regardless of the means of assessment of stenosis. The sensitivity of risk factors, CAC score and the combination for prediction of >50% stenosis when measured by conventional angiogram was considerably higher than when assessed by CTCA but the specificity was considerably higher when assessed by CTCA. The accuracy of CTCA for predicting >50% stenosis using the CAC score alone was higher (AUC 0.85) than using a combination of the CAC score and risk factors with conventional angiography (AUC 0.81). Conclusion: In symptomatic patients, the CAC score is a more accurate predictor of significant coronary stenosis than conventional risk factors.

Background and aims: The influence of gender and age on risk factor prediction of coronary artery calcification (CAC) presence in symptomatic patients is unclear. Methods: From the European Calcific Coronary Artery Disease (EURO-CCAD) cohort, we retrospectively investigated 6309 symptomatic patients, 62% male, from Denmark, France, Germany, Italy, Spain and USA. All had risk factor assessment and CT scanning for CAC scoring. Results: The prevalence of CAC among females was lower than among males in all age groups. Using multivariate logistic regression, age, dyslipidaemia, hypertension, diabetes and smoking were independently predictive of CAC presence in both genders. In addition to a progressive increase in CAC with age, the most important predictors of CAC presence were dyslipidaemia and diabetes (β = 0.64 and 0.63 respectively) in males and diabetes (β = 1.08) followed by smoking (β = 0.68) in females; these same risk factors were also important in predicting increasing CAC scores. There was no difference in the predictive ability of diabetes, hypertension and dyslipidaemia in either gender for CAC presence in patients aged <50 and 50-70 years. However, in patients aged >70, only dyslipidaemia predicted CAC presence in males and only smoking and diabetes were predictive in females. Conclusion: In symptomatic patients, there are significant differences in the ability of conventional risk factors to predict CAC presence between genders and between patients aged <70 and ≥70, indicating the important role of age in predicting CAC presence.

Background and aims: Although much has been written about the risk factor predictors of CAC extent, few studies have been carried out on symptomatic patients. Similarly, no study has directly compared predictors of CAC extent and zero CAC. Methods: From the European Calcific Coronary Artery Disease (Euro-CCAD) cohort, we retrospectively investigated 6309 symptomatic patients, 62% male, from Denmark, France, Germany, Italy, Spain and USA. All had risk factor assessment and CT scanning for CAC scoring. Results: Among all patients, male gender (β = 1.36, p<0.001) and diabetes (β = 0.47, p<0.001) were the most important risk factors of CAC extent, with age, diabetes (DM), obesity, family history of CAD and number of risk factors also being predictive. Among patients with CAC, DM, hypertension (HT) and dyslipidaemia (DL) were predictors of an increasing CAC score in males and females, with DM being the strongest (p<0.001 for both). These results were echoed in quantile regression, where DM was consistently the most important predictor of CAC extent in every quantile in both males and females. HT and DL were also predictive but to a lesser extent, with HT being predictive in the high CAC quantiles and DL in the low CAC quantiles. Conclusion: In addition to male gender, DM is the most important predictor of CAC extent in both genders.

A combinatorial approach is applied to rapidly deposit and screen Ag-Al thin films-to evaluate the mechanical, tribological, and electrical properties as a function of chemical composition. Ag-Al thin films with large continuous composition gradients (6-60 atom % Al) were deposited by a custom-designed combinatorial magnetron sputtering system. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning and transmission electron microscopy (SEM and TEM), X-ray photoelectron spectroscopy (XPS), nanoindentation, and four-point electrical resistance screening were employed to characterize the chemical composition, structure, and physical properties of the films in a time-efficient way. For low Al contents (<13 atom %), a highly (111)-textured fcc phase was formed. At higher Al contents, a (002)-textured hcp solid solution phase was formed followed by a fcc phase in the most At-rich regions. No indication of a mu phase was observed. The Ag-Al films with fcc-Ag matrix is prone to adhesive material transfer leading to a high friction coefficient (>1) and adhesive wear, similar to the behavior of pure Ag. In contrast, the hexagonal solid solution phase (from ca. 15 atom %Al) exhibited dramatically reduced friction coefficients (about 15% of that of the fcc phase) and dramatically reduced adhesive wear when tested against the pure Ag counter surface. The increase in contact resistance of the Ag Al films is limited to only 50% higher than a pure Ag reference sample at the low friction and low wear region (19-27 atom %). This suggests that a hcp Ag Al alloy can have a potential use in sliding electrical contact applications and in the future will replace pure Ag in specific electromechanical applications.

Material transfer from the work materials to the tools strongly influences machining performance and tool life. The influence of Si and Al additions to carbon steel on the material transfer and coating wear in turning with CVD coated carbide tools is investigated. Three model steels are specifically designed to separately study the effects of the individual alloying elements: one reference steel with C as the only alloying element (Base steel), and two steels alloyed also with 1 mass% Si or Al. In the region around the depth of cut on the rake face, where the outside edge of the chip passes over the tool surface, the coating is worn mainly by abrasion when cutting the Base steel. When cutting the Si alloyed steel, an almost pure Si–O transfer layer covers the coating surface, which protects it from wear. When cutting the Al alloyed steel, an almost pure Al–O transfer layer forms on the coating. This layer promotes steel transfer and associated adhesive wear of the coating, which rapidly results in coating detachment and eventually causes notch wear. In the crater region, only the Al alloyed steel results in a transfer layer, an AlN layer that reduces the crater wear.

The main contribution of this paper is a study of the applicability of data smashing - a recently proposed data mining method - for vehicle classification according to the "Nordic system for intelligent classification of vehicles" standard, using measurements of road surface vibrations and magnetic field disturbances caused by passing vehicles. The main advantage of the studied classification approach is that it, in contrast to the most of traditional machine learning algorithms, does not require the extraction of features from raw signals. The proposed classification approach was evaluated on a large dataset consisting of signals from 3074 vehicles. Hence, a good estimate of the actual classification rate was obtained. The performance was compared to the previously reported results on the same problem for logistic regression. Our results show the potential trade-off between classification accuracy and classification method's development efforts could be achieved.

The pulp and paper industry is a large global industry producing millions of tons of paper each year. To produce pulp for this paper, only a handful of processes are used. One of these is the mechanical pulping process, called Pressure Ground Wood (PGW). Although commonly used, the tribological details of the mechanisms behind the stochastic fiber separation are not well known. In order to study these mechanisms, and the influence of geometries at the tool surface, a test equipment allowing testing in a similar, but more controlled, environment is needed. For this purpose, a lab scale rig has been designed, capable of grinding at temperatures and pressures at industrially relevant conditions. The tools used are made of CVD-diamond thin films, structured into different well defined patterns of sharp edges. Samples of Norway spruce have been ground both using these tools and a conventional grinding stone surface. The fibers produces are compared and the possibility of controlling the fiber characteristics using the designed tools is discussed.