In this study, we investigate the mechanical behavior of each skin layer, in terms of the nominal stress-strain curve by uniaxial tensile tests using specimens of porcine skin in two forms: dermis containing epidermis, and all three layers. All tests were performed under cyclic loading at the constant strain rate of 10–3 s–1 at ambient temperature. To measure the precise initial cross-sectional areas of each layer, the thickness of each skin layer was quantified by counting the number of pixels on the photo-image using image-processing software. In the tensile test, force-strain curves of the total skin and dermis with epidermis were obtained. Subsequently, a rule of mixtures was applied to determine the nonlinear mechanical properties of the hypodermis layer. In conclusion, we could define the uniaxial tensile behavior of the hypodermis, and additionally predict the weight effect of the dermis and hypodermis layers in the tensile test.
Uniaxial tensile tests were performed on porcine skin to investigate the tensile stress-strain constitutive characteristic at quasistatic deformations using uniaxial tensile tests. Experimental results were then used to determine the parameters of the various constitutive model types for rubber, including the Mooney-Rivlin, Yeoh, Ogden, and others. The Prony series viscoelastic model was also calibrated based on the stress relaxation test. To investigate the calibrated constitutive equations (visco-hyperelastic), the falling impact test was conducted. From the viewpoint of the maximum impact load, the error was approximately 15.87%. Overall, the Ogden model predicted the experimental measurements most reasonably. The calibrated constitutive model is expected to be of practical use in describing the mechanical properties of porcine skin.
The paper presents a procedure for correction of the error of an ECG signal, introduced by the skin-electrode interface. This procedure involves three main measuring-calculating stages: parametrical identification of the mathematical model of the interface, realized directly before the diagnostic measurements, registration of the signal at the output of electrodes as well as reconstruction of the input signal of the interface.
The first two stages are realized in the on-line mode, whereas the operation of signal reconstruction presents a numerical task of digital signal processing and is realized in the off-line mode through deconvolution of the registered signal with the transfer function of the skin-electrode interface.
The aim of the paper is to discuss in detail the procedure of parametric identification of the skin-electrode interface with the use of a computer system equipped with a DAQ card and LabVIEW software. The algorithm for error correction introduced by this interface is also presented.
In this article, we present a comprehensive measurement system to determine the level of user emotional arousal by the analysis of electrodermal activity (EDA). A number of EDA measurements were collected, while emotions were elicited using specially selected movie sequences. Data collected from 16 participants of the experiment, in conjunction with those from personal questionnaires, were used to determine a large number of 20 features of the EDA, to assess the emotional state of a user. Feature selection was performed using signal processing and analysis methods, while considering user declarations. The suitability of the designed system for detecting the level of emotional arousal was fully confirmed, throughout the number of experiments. The average classification accuracy for two classes of the least and the most stimulating movies varies within the range of 61‒72%.
During drilling through aquifers using the rotary drilling method with drilling fluid application, the phenomenon of formation clogging in near-well zone takes place. This leads to physical changes in pore spaces in consequence of the deposition solid phase particles originating from the drilling fluid. Due to this fact, filtration velocity in the clogged zones of the aquifer formation decreases, which results in increased pressure drawdown and decreased well hydraulic efficiency. Therefore, it causes a reduction of the well total capacity. The article consists of studies connected to the development of the mud which will constitute the basis for a complex mud system intended for hydrogeological drilling in different encountered geological conditions. In the framework of laboratory research, technological parameters of six, commonly applied in oil and gas industry, polymer agents as well as new agent developed at the Drilling, Oil and Gas Faculty AGH-UST in Krakow were examined. The undertaken studies showed that the new agent, marked as CAGEx, provides the required technological parameters and can be applied as a base for drilling muds intended for hydrogeological drilling. The undertaken industrial research of the new CAGEx drilling mud carried out while drilling water intake well, confirmed the great stability of its technological parameters as well as insignificant influence on rock permeability damage in filter zone. The water intake well is characterized by high hydraulic efficiency and does not require additional activation treatment.
Skin dynamic termography supplemented by a mathematical model is presented as an objective and sensitive indicator of the skin prick test result. Termographic measurements were performed simultaneously with routine skin prick tests. The IR images were acquired every 70 s up to 910 s after skin prick. In the model histamine is treated as the principal mediator of the allergic reaction. Histamine produces vasolidation and the engorged vessels are responsible for an increase in skin temperature. The model parameters were determined by fitting the analytical solutions to the spatio-temporal distributions of the differences between measured and baseline temperatures. The model reproduces experimental data very well (coefficient of determination = 0.805÷0.995). The method offers a set of parameters to describe separately skin allergic reaction and skin reactivity. The release of histamine after allergen injection is the best indicator of allergic response. The diagnostic parameter better correlates with the standard evaluation of a skin prick test (correlation coefficient = 0.98) than the result of the thermographic planimetric method based on temperature and heated area determination (0.81). The high sensitivity of the method allows for determination of the allergic response in patients with the reduced skin reactivity.
Investigating human emotions empirically is still considered to be challenging, mostly due to the questionable validity of the results obtained when employing individual types of measures. Among the most frequently used methods to study emotional reactions are self-report, autonomic, neurophysiological, and behavioral measures. Importantly, previous studies on emotional responding have rarely triangulated the aforementioned research methods. In this paper we discuss main methodological considerations related to the use of physiological and self-report measures in emotion studies, based on our previous research on the processing of emotionally-laden narratives in the native and non-native language, where we employed the SUPIN S30 questionnaire as a self-report tool, and galvanic skin response (GSR) as a physiological measure (Jankowiak & Korpal, 2018). The findings revealed a more pronounced reaction to stimuli presented in the native relative to the non-native language, which was however reflected only in GSR patterns. The lack of correlation between GSR and SUPIN scores might have resulted from a number of methodological considerations, such as social desirability bias, sensitive questions, lack of emotional self-awareness, compromised ecological validity, and laboratory anxiety, all of which are thoroughly discussed in the article.
Measurement of the perfusion coefficient and thermal parameters of skin tissue using dynamic thermography is presented in this paper. A novel approach based on cold provocation and thermal modelling of skin tissue is presented. The measurement was performed on a person’s forearm using a special cooling device equipped with the Peltier module. The proposed method first cools the skin, and then measures the changes of its temperature matching the measurement results with a heat transfer model to estimate the skin perfusion and other thermal parameters. In order to assess correctness of the proposed approach, the uncertainty analysis was performed.
Trophic disorders like reduced skin blood circulation are well−known epiphenomenon of cerebral palsy (CP). They can influence quality of life and can lead to skin damages and, as a consequence, to decubitus. Therefore, it is important to analyse temperature regulation in patients with CP. Thermal imaging camera FLIR BCAM SD was used to study the dependency of skin blood circulation in upper extremities of patients with CP on hand dominance, hand force and hand volume. The hand force was evaluated using a conventional dynamometer. The hand volume was measured with a volumeter. A cold stress test for hands was applied in 22 patients with CP and 6 healthy subjects. The warming up process after the test was recorded with the thermal camera. It was confirmed that the hands of patients warm up slower comparing to healthy persons. The patients’ working hands warm up faster than non−working ones. A slight correlation was established between the hand grip force of the working hands and their warm up time. No correlation was found between the warming up time and the volume of the hand. The results confirm our assumption that there is a connection of peripheral blood circulation to upper limb motor functions.
In the last few years, a great attention was paid to the deep learning Techniques used for image analysis because of their ability to use machine learning techniques to transform input data into high level presentation. For the sake of accurate diagnosis, the medical field has a steadily growing interest in such technology especially in the diagnosis of melanoma. These deep learning networks work through making coarse segmentation, conventional filters and pooling layers. However, this segmentation of the skin lesions results in image of lower resolution than the original skin image. In this paper, we present deep learning based approaches to solve the problems in skin lesion analysis using a dermoscopic image containing skin tumor. The proposed models are trained and evaluated on standard benchmark datasets from the International Skin Imaging Collaboration (ISIC) 2018 Challenge. The proposed method achieves an accuracy of 96.67% for the validation set .The experimental tests carried out on a clinical dataset show that the classification performance using deep learning-based features performs better than the state-of-the-art techniques.
Allergic skin diseases in cats are amongst the most prevalent dermatological conditions in this species. The objectives of this study were to evaluate different types of skin barrier measurements in healthy cats and cats with non-flea non-food hypersensitivity dermatitis (NFNFHD). 24 clinically healthy and 19 NFNFHD cats were included in this clinical trial. In each animal, the transepidermal water loss (TEWL) and skin hydration (SH) were assessed on six clipped body sites by VapoMeter SWL 4605 and Corneometer ®CM 825, respectively. Results of TEWL measurement were , significantly higher in one of the six examined body sites, namely on the lumbar area (p=0.0049). Furthermore, a statistically significant difference was found between the average TEWL values (p=0.019). Statistically notable differences were mea- sured at least in one certain body site for SH: in the groin (p=0.02), where the values in the affect- ed cats were lower than in the healthy individuals. These results may suggest that in NFNFHD cats transepidermal water loss is higher than in healthy cats. Skin hydration is, at least, in certain body sites, lower in atopic feline patients than in healthy individuals.
Accurate prediction of power loss distribution within an electrical device is highly desirable as it allows thermal behavior to be evaluated at the early design stage. Three-dimensional (3-D) and two-dimensional (2-D) finite element analysis (FEA) is applied to calculate dc and ac copper losses in the armature winding at high-frequency sinusoidal currents. The main goal of this paper is showing the end-winding effect on copper losses. Copper losses at high frequency are dominated by the skin and proximity effects. A time-varying current has a tendency to concentrate near the surfaces of conductors, and if the frequency is very high, the current is restricted to a very thin layer near the conductor surface. This phenomenon of nonuniform distribution of time-varying currents in conductors is known as the skin effect. The term proximity effect refers to the influence of alternating current in one conductor on the current distribution in another, nearby conductor. To evaluate the ac copper loss within the analyzed machine a simplified approach is adopted using one segment of stator core. To demonstrate an enhanced copper loss due to ac operation, the dc and ac resistances are calculated. The resistances ratio ac to dc is strongly dependent on frequency, temperature, shape of slot and size of slot opening.
The aim of this paper is to derive an analytical equations for the temperature dependent optimum winding size of inductors conducting high frequency ac sinusoidal currents. Derived analytical equations are useful designing tool for research and development engineers because windings made of foil, square-wire, and solid-round-wire windings are considered. Temperature dependent Dowell’s equation for the ac-to-dc winding resistance ratio is given and approximated. Thermally dependent analytical equations for the optimum foil thickness, as well as valley thickness and diameter of the square-wire and solid-round-wire windings are derived from approximated thermally dependent ac-to-dc winding resistance ratios. Minimum winding ac resistance of the foil winding and local minimum of the winding ac resistance of the solid-round-wire winding are verified with Maxwell 3D Finite Element Method simulations.
This paper expands the M-K curve theory with examples of the most commonly mentioned pile-soil mechanics behaviours in the literature and their corresponding κ2 variations. A brief introduction shows the history of the Meyer-Kowalow theory and its basic assumptions. This is followed by the relationship between in situ investigation CPT results, with parameters C1, C2, Ct used to approximate the load-settlement curve according to the M-K theory. The Meyer-Kowalow curve satisfies asymptotic behaviour for small loads, where linear theory applies, and for limit loads, when pile displacement is out of control. Essential in the description are constant parameters C, which refer to the aggregated Winklers modulus, Ngr limit loads and k, which is crucial for static load test results. For this reason, the authors sought to calculate the κ value based upon soil mechanics principles. This article shows methods for checking statistical mathematical calculations, published earlier by Meyer using CPT investigations. It presents real case calculations and directions for future planned research.
The paper presents a research concerning the issue of visualization of blood vessels in the human body. In the initial phase of the investigations the focus was on understanding the optical properties of human body tissues. Optical transmittance of human skin was measured. Skin transmittance reaches the maximum at around 670–850 nm and 970–1100 nm. The optimal wavelength suitable for work in reflected and transmitted light was chosen. It was based on extracting blood vessels from the image for using them further in a developed system. A unique measuring system with an integrated illuminator and highly sensitive light detectors for medical imaging and stereoscopic observation was created. The high usable value of the developed system was largely gained by the original numerical program for development of measurement results. The elaborated system of blood vessels’ visualization is a mobile device. It was tested for imaging subcutaneous blood vessels. Three-dimensional observation of circulation and microcirculation in subcutaneous breast tissues is possible. Practical tests of the elaborated device for blood vessels’ medical stereoscopic observations were presented. Tests at a wavelength of 850 nm were performed. It is planned to conduct patient tests in the future at the Maria Skłodowska-Curie Institute - Oncology Center (MSCI), the Branch in Gliwice, Poland.
Due to the skin effect of eddy currents, the depth of cracks which can be detected by the traditional eddy current probe is very limited. In order to improve the ability of eddy current probes to inspect deep cracks in metal thick-walled structures, a new eddy current probe using an excitation system with phase shifted fields was proposed. Its feasibility for detecting deep cracks was verified by simulation and experiments. The results showed that the penetration depth of eddy currents in austenitic stainless steel is effectively enhanced by using the new probe.
Staphylococcus pseudintermedius (SP) and methicillin-resistant SP (MRSP) is one of the most important veterinary pathogens in the dog. Herein, from a total of 126 S. pseudintermedius strains, 23 MRSP (18%) were identified. Multi-Locus Sequence Typing (MLST) revealed that most of MRSP strains belonged to ST71 (26%), which have been already reported in Italy and other countries. Interestingly, nine new sequence types (39%), from 1053 up to 1061, were described for the first time. Moreover, the isolated MRSP strains showed relevant antibiotic resistance profiles. This report highlights the circulation of new sequence types of MRSP in Italy and underlines the need of a global epidemiological surveillance to limit the increasing spread of multidrug-resistant MRSP strains worldwide, since they may represent a considerable concern for dog’s health.