bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the Fracture Toughness KIc for Selected Magnetron Sputtering Coatings by Using the Laugier Model
Authors: Smolik Jerzy , Sowa Sylwia , Kacprzyńska-Gołacka Joanna , Piasek Artur
Published: December 2022

Nanoindentation is one of the methods that allows for determining the fracture properties of brittle materials. In this article, the authors present the possibility of the fracture toughness coefficient calculation of ceramic-based coatings doped by metal (W, Cr) by using the nanoindentation method with the Berkovich diamond indenter. The mechanical properties of selected coatings, such as hardness and Young’s modulus, were investigated from nanohardness experiments. We analyzed the brittle fracture, which includes changes in hardness (H), Young’s modulus (E), plasticity index H/E and resistance to plastic deformation H3/E2, enabled the concentration of tungsten and chromium. Due to the size of the indentation and the size of the initial cracks, it is necessary to use Scanning Electron Microscopy (SEM) to observe and measure the indentations made and the generated cracks. For evaluation of the fracture toughness in mode I, the Laugier model was chosen experimentally. The fracture toughness analysis showed that doping with concentrations of 10% W and 10% Cr causes an increase in the fracture toughness for KIc = 4.98 for TiBW (10%) and KIc = 6.23 for TiBCr (10%).
The Influence of Co Addition on the Structure and Mechanical Properties of Tungsten Heavy Alloys
Authors: Skoczylas Paweł , Kaczorowski Mieczysław
Published: December 2022

This study shows the results of Ni replacement with Co in a W-Ni-Co-type tungsten heavy alloy (WHA) in terms of the structure and mechanical properties. Five alloys containing 92 wt. % of tungsten plus Ni and Co changing in the proportions (Co:Ni) of 1:9, 2:8, 3:7, 4:6, and 5:5 were prepared using liquid phase sintering (LPS). The specimens were studied directly after sintering and after solution heat treatment. The tensile strength, yield strength, and elongation were evaluated. The results of tensile tests were supplemented with microhardness measurements of tungsten grains and matrix. Light microscopy was used for the microstructure, and a scanning electron microscope (SEM) equipped with an EDS attachment was applied for the assessment of the fracture mode and chemical microanalysis. It was concluded that the replacement of Ni with Co led to a tensile property increase that was accompanied by a gradual decrease in elongation that started to be critical for a Co:Ni ratio higher than 4:6.
Prediction Model of Three-Dimensional Machined Potassium Dihydrogen Phosphate Surfaces Based on a Dynamic Response Machining System
Authors: Pang Qilong , Xiong Jianlong
Published: December 2022

To comprehensively obtain the effect of the machining process on the three-dimensional surface topography of machined potassium dihydrogen phosphate crystals, a dynamic response model of a machining system was built to calculate the dynamic displacement variables in the different processing directions. This model includes almost all processing factors, such as cutting parameters, environment vibration, radial and axial runout of the spindle, cutting tool parameters, material parameters, guide way error, fast tool servo and lubrication condition errors, etc. Compared with the experimental results, the three-dimensional topographies and two-dimensional profiles of the simulation surfaces were nearly consistent with those of experimental machined surfaces. As the simulation shows, the cutting parameters, axial runout of the spindle, and the output noise of the fast tool servo can respectively impact the main, low, and high frequencies of the machined surface topography. The main frequency of all the simulated and experimental surfaces in this study was 0.0138 μm−1. The low and high frequencies of the simulation surfaces had slight differences, about 0.003 μm−1 from those of the experimental surfaces. The simulation model, based on dynamic response, can accurately predict the entire machining process and three-dimensional topographies of machined potassium dihydrogen phosphate surfaces.
Effect of Ti3SiC2 and Ti3AlC2 Particles on Microstructure and Wear Resistance of Microarc Oxidation Layers on TC4 Alloy
Authors: Gu Gaoyang , Shang Jian , Lin Dan
Published: December 2022

Microarc oxidation (MAO) layers were prepared using 8g/L Na2SiO3 + 6g/L (NaPO3)6 + 4g/L Na2WO4 electrolyte with the addition of 2g/L Ti3SiC2/Ti3AlC2 particles under constant-current mode. The roughness, porosity, composition, surface/cross-sectional morphology, and frictional behavior of the prepared MAO layers were characterized by 3D real-color electron microscopy, scanning electron microscopy, X-ray energy spectrometry, X-ray diffractometry, and with a tribo-tester. The results showed that the addition of Ti3SiC2 and Ti3AlC2 to the electrolyte reduced the porosity of the prepared layers by 9% compared with that of the MAO layer without added particles. The addition of Ti3SiC2/Ti3AlC2 also reduced the friction coefficient and wear rate of the prepared layers by 35% compared with that of the MAO layer without added particles. It was found that the addition of Ti3AlC2 particles to the electrolyte resulted in the lowest porosity and the lowest wear volume.
Impact of Location and Insulation Material on Energy Performance of Residential Buildings as per Saudi Building Code (SBC) 601/602 in Saudi Arabia
Authors: Alyami Saleh H. , Alqahtany Ali , Ashraf Noman , Osman Abdelbagi , Aldossary Naief Ali , Almutlaqa Ayman , Al-Maziad Faris , Alshammari Maher S. , Al-Gehlani Wadee Ahmed Ghanem
Published: December 2022

In hot and humid climates, a significant part of the energy is used to cool the building. There are several ways to reduce this air conditioning load, but one standout is through the selection and design of the right building envelope and its components. The thermal characteristics of the building envelope, in particular the thermal resistance of the insulation used, have an impact on the thermal and energy performance of building structures. Thermal conductivity, which indicates the ability of heat to move through a material given a temperature difference, is the primary factor affecting the performance of a thermal insulation material. Both temperature and humidity changes can affect a material’s thermal conductivity value, which can then change. In fact, due to the fluctuating ambient air temperature and solar radiation, thermal insulation in buildings is susceptible to significant and continuous temperature variations. Thermal insulation used in building walls and roofs helps to reduce the energy demand of the building. It improves thermal comfort and, if used correctly, reduces the operational cost of the building. The present study has focused on the effects of location and insulation material on the energy performance of a residential building by considering five climatic locations in the Kingdom of Saudi Arabia (KSA). Five commonly used insulation materials with different thermal characteristics, namely polyurethane board (PU), expanded polystyrene (EPS), glass wool (GW), urea-formaldehyde foam (UFF), and expanded perlite (EP), were analyzed under various climatic zones as per the Saudi Building Code 601/602. The selected cities were categorized based on cooling degree days (CDD) and outdoor dry bulb temperature (DBT) as hot, very hot, and extremely hot climatic zones. Insulation improves thermal comfort and, if used correctly, reduces running costs. Experiments were conducted to determine the thermal conductivity, and the energy simulation was performed by employing IES-VE software for various insulation options. The findings indicate that the location has a significant impact on the energy performance of the insulating materials. The energy saving potential of polyurethane board (PU) insulation is more attractive in cities with higher DBTs and CDDs than in cities with lower DBTs and CDDs. The benefit of installing insulation ranged from a 2 to 14% decrease in energy demand for the climate zones studied. The sensitivity analysis showed that the energy saving potential of the insulation materials is sensitive to the set-point temperature (ST) band.
On the Use of Multi-Step Dies for Improving the Performance against Hydrogen Embrittlement of Cold Drawn Prestressing Steel Wires
Authors: Toribio Jesús , Lorenzo Miguel
Published: December 2022

The main cause of in-service failure of cold drawn wires in aggressive environments is hydrogen embrittlement (HE). The non-uniform plastic strains and residual stresses generated after cold drawing play a significant role in the matter of HE susceptibility of prestressing steels. In this paper, a new and innovative design of the drawing scheme is developed, geared towards the reduction in both manufacturing-induced residual stresses and plastic strains. To achieve this goal, three innovative cold drawing chains (consisting in diverse multi-step dies where multiple diameter reductions are progressively carried out in a single die) are numerically simulated by the finite element (FE) method. From the residual stress and plastic strain fields revealed from FE numerical simulations, hydrogen accumulation for diverse times of exposure is obtained by means of FE simulations of the hydrogen diffusion assisted by stress and strains. Thus, an estimation of the HE susceptibility of the cold drawn wires after each process was obtained. Results reveal that cold drawn wire using multi-step dies exhibits lower stress and strain states nearby the wire surface. This reduction causes a decrease in the hydrogen concentration at the prospective damage zones, thereby improving the performance of the prestressing steel wires in hydrogenating environments promoting HE. Thus, the optimal wire drawing process design is carried out using special dies with several reductions per die.
Non-Volatile Memory and Synaptic Characteristics of TiN/CeOx/Pt RRAM Devices
Authors: Ha Hoesung , Pyo Juyeong , Lee Yunseok , Kim Sungjun
Published: December 2022

In this study, we investigate the synaptic characteristics and the non-volatile memory characteristics of TiN/CeOx/Pt RRAM devices for a neuromorphic system. The thickness and chemical properties of the CeOx are confirmed through TEM, EDS, and XPS analysis. A lot of oxygen vacancies (ions) in CeOx film enhance resistive switching. The stable bipolar resistive switching characteristics, endurance cycling (>100 cycles), and non-volatile properties in the retention test (>10,000 s) are assessed through DC sweep. The filamentary switching model and Schottky emission-based conduction model are presented for TiN/CeOx/Pt RRAM devices in the LRS and HRS. The compliance current (1~5 mA) and reset stop voltage (−1.3~−2.2 V) are used in the set and reset processes, respectively, to implement multi-level cell (MLC) in DC sweep mode. Based on neural activity, a neuromorphic system is performed by electrical stimulation. Accordingly, the pulse responses achieve longer endurance cycling (>10,000 cycles), MLC (potentiation and depression), spike-timing dependent plasticity (STDP), and excitatory postsynaptic current (EPSC) to mimic synapse using TiN/CeOx/Pt RRAM devices.
Control of Trajectory Tracking for Mobile Manipulator Robot with Kinematic Limitations and Self-Collision Avoidance
Authors: Qiao Lijun , Luo Xiao , Luo Qingsheng
Published: December 2022

In this paper, we propose an optimized differential evolution algorithm based on kinematic limitations and structural complexity constraints to solve the trajectory tracking problem for a mobile manipulator robot. The traditional method mainly involves obtaining the speed of the control variable based on the Jacobian inverse or linearization of the robot’s kinematic model, which cannot avoid the singularity position and/or self-collision phenomena. To address these problems, we directly design an optimized differential evolution algorithm to solve the trajectory planning problem for mobile manipulator robots. First, we analyze various constraints on the actual movement and describe them specifically using various equations or inequalities, including non-holonomic constraints on the mobile platform, the physical limitations of the driving motors, self-collision avoidance restriction, and smoothly traversing the singularity position. Next, we re-define the trajectory tracking of a mobile manipulator robot as an optimization problem under multiple constraints, including the trajectory tracking task and various constraints simultaneously. Then, we propose a new differential evolution (DE) algorithm by optimizing some critical operations to solve the optimization problem, such as improving the population’s distribution, limiting the population distribution range, and adding a success index. Additionally, we design two simple trajectories and two complex trajectories to determine the performance of the optimized DE algorithm in solving the trajectory tracking problem. The results demonstrate that the optimized DE algorithm can effectively realize the high-precision trajectory tracking task of a differential wheeled mobile manipulator robot through the consideration of kinematic limitations and self-collision avoidance.
Thermal Properties Prediction of Large-Scale Machine Tool in Vacuum Environment Based on the Parameter Identification of Fluid–Thermal Coupling Model
Authors: Li Tianjian , Xi Guobin , Wang Han , Tang Wa , Shao Zhongxi , Sun Xizhi
Published: December 2022

A high vacuum environment safeguards the performance of special processing technologies and high-precision parts such as nanosecond laser processing, chip packaging, and optical components. However, it poses higher requirements for the machine tool, which makes the temperature control of machine tools an important goal in design and development. In this paper, the thermal properties of a large-scale 5-axis laser processing machine tool in a vacuum environment were investigated. The thermal contact resistance between parts is identified by the parametric simulation and experiment. The whole machine temperature field was then obtained based on the fluid–thermal coupling model and verified by experiment. The results showed that the thermal contact resistance of the motor and reducer with the water cold plate was 560 W/(m2∙°C) and 510 W/(m2∙°C), respectively, and the maximum temperature increase of the machine was 3 °C. Based on the results, the machine tool’s temperature increase prediction chart was obtained by simulation under different processing conditions such as cooling water flow rate, cooling water temperature, motor speed, and ambient temperature. It provides technical and data references for the research on the thermal stability of the machine tool in processing.
Mask-Guided Generation Method for Industrial Defect Images with Non-uniform Structures
Authors: Wei Jing , Zhang Zhengtao , Shen Fei , Lv Chengkan
Published: December 2022

Defect generation is a crucial method for solving data problems in industrial defect detection. However, the current defect generation methods suffer from the problems of background information loss, insufficient consideration of complex defects, and lack of accurate annotations, which limits their application in defect segmentation tasks. To tackle these problems, we proposed a mask-guided background-preserving defect generation method, MDGAN (mask-guided defect generation adversarial networks). First, to preserve the normal background and provide accurate annotations for the generated defect samples, we proposed a background replacement module (BRM), to add real background information to the generator and guide the generator to only focus on the generation of defect content in specified regions. Second, to guarantee the quality of the generated complex texture defects, we proposed a double discrimination module (DDM), to assist the discriminator in measuring the realism of the input image and distinguishing whether or not the defects were distributed at specified locations. The experimental results on metal, fabric, and plastic products showed that MDGAN could generate diversified and high-quality defect samples, demonstrating an improvement in detection over the traditional augmented samples. In addition, MDGAN can transfer defects between datasets with similar defect contents, thus achieving zero-shot defect detection.
Solitary Wave Solutions for the Stochastic Fractional-Space KdV in the Sense of the M-Truncated Derivative
Authors: Mohammed Wael W. , Cesarano Clemente , Al-Askar Farah M. , El-Morshedy Mahmoud
Published: December 2022

The stochastic fractional-space Korteweg–de Vries equation (SFSKdVE) in the sense of the M-truncated derivative is examined in this article. In the Itô sense, the SFSKdVE is forced by multiplicative white noise. To produce new trigonometric, hyperbolic, rational, and elliptic stochastic fractional solutions, the tanh–coth and Jacobi elliptic function methods are used. The obtained solutions are useful in interpreting certain fascinating physical phenomena because the KdV equation is essential for understanding the behavior of waves in shallow water. To demonstrate how the multiplicative noise and the M-truncated derivative impact the precise solutions of the SFSKdVE, different 3D and 2D graphical representations are plotted.
Deep Multi-Task Learning for an Autoencoder-Regularized Semantic Segmentation of Fundus Retina Images
Authors: Jin Ge , Chen Xu , Ying Long
Published: December 2022

Automated segmentation of retinal blood vessels is necessary for the diagnosis, monitoring, and treatment planning of the disease. Although current U-shaped structure models have achieved outstanding performance, some challenges still emerge due to the nature of this problem and mainstream models. (1) There does not exist an effective framework to obtain and incorporate features with different spatial and semantic information at multiple levels. (2) The fundus retina images coupled with high-quality blood vessel segmentation are relatively rare. (3) The information on edge regions, which are the most difficult parts to segment, has not received adequate attention. In this work, we propose a novel encoder–decoder architecture based on the multi-task learning paradigm to tackle these challenges. The shared image encoder is regularized by conducting the reconstruction task in the VQ-VAE (Vector Quantized Variational AutoEncoder) module branch to improve the generalization ability. Meanwhile, hierarchical representations are generated and integrated to complement the input image. The edge attention module is designed to make the model capture edge-focused feature representations via deep supervision, focusing on the target edge regions that are most difficult to recognize. Extensive evaluations of three publicly accessible datasets demonstrate that the proposed model outperforms the current state-of-the-art methods.
Hölder Space Theory for the Rotation Problem of a Two-Phase Drop
Authors: Denisova Irina V. , Solonnikov Vsevolod A.
Published: December 2022

We investigate a uniformly rotating finite mass consisting of two immiscible, viscous, incompressible self-gravitating fluids which is governed by an interface problem for the Navier–Stokes system with mass forces and the gradient of the Newton potential on the right-hand sides. The interface between the liquids is assumed to be closed. Surface tension acts on the interface and on the exterior free boundary. A study of this problem is performed in the Hölder spaces of functions. The global unique solvability of the problem is obtained under the smallness of the initial data, external forces and rotation speed, and the proximity of the given initial surfaces to some axisymmetric equilibrium figures. It is proved that if the second variation of the energy functional is positive and mass forces decrease exponentially, then small perturbations of the axisymmetric figures of equilibrium tend exponentially to zero as the time t→∞, and the motion of liquid mass passes into the rotation of the two-phase drop as a solid body.
Reclamation of a Resource Extraction Site Model with Random Components
Authors: Gromova Ekaterina , Zaremba Anastasiia , Masoudi Nahid
Published: December 2022

We compute the cooperative and the Nash equilibrium solutions for the discounted optimal control problem in a two-player differential game of reclamation of a resource extraction site, where each firm’s planning horizon presents the period that extraction of the resources from their site is economically viable. Hence, the planning horizon is defined by a random duration determined on the infinite time horizon. The comparison of the cooperative and Nash solutions and also the comparative statics are provided numerically. We also define the concept of “normalized value of cooperation” and explain how this concept could help us to better characterize the losses the players will face if they continue to refrain from cooperation.
Classification of Driver Distraction Risk Levels: Based on Driver’s Gaze and Secondary Driving Tasks
Authors: Zheng Lili , Zhang Yanlin , Ding Tongqiang , Meng Fanyun , Li Yanlin , Cao Shiyu
Published: December 2022

Driver distraction is one of the significant causes of traffic accidents. To improve the accuracy of accident occurrence prediction under driver distraction and to provide graded warnings, it is necessary to classify the level of driver distraction. Based on naturalistic driving study data, distraction risk levels are classified using the driver’s gaze and secondary driving tasks in this paper. The classification results are then combined with road environment factors for accident occurrence prediction. Two ways are suggested to classify driver distraction risk levels in this study: one is to divide it into three levels based on the driver’s gaze and the AttenD algorithm, and the other is to divide it into six levels based on secondary driving tasks and odds ratio. Random Forest, AdaBoost, and XGBoost are used to predict accident occurrence by combining the classification results, driver characteristics, and road environment factors. The results show that the classification of distraction risk levels helps improve the model prediction accuracy. The classification based on the driver’s gaze is better than that based on secondary driving tasks. The classification method can be applied to accident risk prediction and further driving risk warning.
Advanced Algorithms in Automatic Generation Control of Hydroelectric Power Plants
Authors: Kazantsev Yury V. , Glazyrin Gleb V. , Khalyasmaa Alexandra I. , Shayk Sergey M. , Kuparev Mihail A.
Published: December 2022

The problem of load distribution between hydraulic units at hydropower plants is a difficult task due to the nonlinearity of hydro turbine characteristics and individual peculiarities of the generation units, in which operating conditions are often different. It is necessary to apply the most up-to-date optimization methods that take into account the nonlinearity of the turbine characteristics. The methods must also consider strict constraints on the operation conditions of the power equipment when searching for the extremum of the objective function specified in the form of equalities and inequalities. When solving the aforementioned optimization problem, the constraints on computing capacities of the digital automatic generation control systems that must operate in real-time mode were taken into account. To solve the optimization task, the interior point method was analyzed and the method of Lagrange multipliers was modified so that it could minimize turbine discharge and active energy losses in the windings of the power generators and unit power transformers. The article presents the simulation results of the developed optimization algorithms and the results of the field tests of the automatic generation control system executing the proposed algorithms. All of the tests showed a fairly high efficiency of the proposed optimization methods in real operation conditions.
A Semiparametric Bayesian Joint Modelling of Skewed Longitudinal and Competing Risks Failure Time Data: With Application to Chronic Kidney Disease
Authors: Ferede Melkamu Molla , Mwalili Samuel , Dagne Getachew , Karanja Simon , Hailu Workagegnehu , El-Morshedy Mahmoud , Al-Bossly Afrah
Published: December 2022

In clinical and epidemiological studies, when the time-to-event(s) and the longitudinal outcomes are associated, modelling them separately may give biased estimates. A joint modelling approach is required to obtain unbiased results and to evaluate their association. In the joint model, a subject may be exposed to more than one type of failure event (competing risks). Considering the competing event as an independent censoring of the time-to-event process may underestimate the true survival probability and give biased results. Within the joint model, longitudinal outcomes may have nonlinear (irregular) trajectories over time and exhibit skewness with heavy tails. Accordingly, fully parametric mixed-effect models may not be flexible enough to model this type of complex longitudinal data. In addition, assuming a Gaussian distribution for model errors may be too restrictive to adequately represent within-individual variations and may lack robustness against deviation from distributional assumptions. To simultaneously overcome these issues, in this paper, we presented semiparametric joint models for competing risks failure time and skewed-longitudinal data by using a smoothing spline approach and a multivariate skew-t distribution. We also considered different parameterization approaches in the formulation of joint models and used a Bayesian approach to make the statistical inference. We illustrated the proposed methods by analyzing real data on a chronic kidney disease. To evaluate the performance of the methods, we also carried out simulation studies. The results of both the application and simulation studies revealed that the joint modelling approach proposed in this study performed well when the semiparametric, random-effects parameterization, and skew-t distribution specifications were taken into account.
About Some Monge–Kantovorich Type Norm and Their Applications to the Theory of Fractals
Authors: Mierluș-Mazilu Ion , Niță Lucian
Published: December 2022

If X is a Hilbert space, one can consider the space cabv(X) of X valued measures defined on the Borel sets of a compact metric space, having a bounded variation. On this vector measures space was already introduced a Monge–Kantorovich type norm. Our first goal was to introduce a Monge–Kantorovich type norm on cabv(X), where X is a Banach space, but not necessarily a Hilbert space. Thus, we introduced here the Monge–Kantorovich type norm on cabvLq([0,1]),(1<q<∞). We obtained some properties of this norm and provided some examples. Then, we used the Monge–Kantorovich norm on cabvKn(K being R or C) to obtain convergence properties for sequences of fractal sets and fractal vector measures associated to a sequence of iterated function systems.
Predictive Factors for the Prognosis of Alcoholic Liver Cirrhosis
Authors: Trifan Anca , Minea Horia , Rotaru Adrian , Stanciu Carol , Stafie Remus , Stratina Ermina , Zenovia Sebastian , Nastasa Robert , Singeap Ana-Maria , Girleanu Irina , Muzica Cristina , Huiban Laura , Cuciureanu Tudor , Chiriac Stefan , Sfarti Catalin , Cojocariu Camelia
Published: December 2022

Alcoholic liver cirrhosis (ALC) is a disease with multiple complications and is associated with poor prognosis and significant mortality. Identifying risk factors associated with a poor outcome is important to ensure effective treatment and increase life expectancy. We aimed to evaluate the predictive values of complications regarding mortality in ALC. We retrospectively analyzed 1429 patients with ALC hospitalized between January 2019 and April 2022 at the Institute of Gastroenterology and Hepatology Iasi. The electronic medical records were interrogated to obtain information about demographic data, complications, comorbidities, and prognostic scores: MELD-Na (model for end-stage liver disease-sodium) and CTP (Child–Turcotte–Pugh). Based on uni- and multivariate analysis, independent predictors of mortality were identified. The mean age at diagnosis was 56.15 ± 11.49 years with a ratio of 2:1 in favor of males. There were 296 deaths (20.8%), most of them during the first hospitalization (208/14.6%). It was observed during the univariate analysis that complications of the disease negatively affected the survival rate, significant values being related to infections (sepsis; OR = 21.98; p < 0.001; spontaneous bacterial peritonitis (SBP) (OR = 11.94; p < 0.001) and hepatorenal syndrome (HRS) (OR = 9.35; p < 0.001). The independent predictors, confirmed by multivariate analysis, were the association of variceal bleeding, infections, and hepatic encephalopathy or ascites, each combination being responsible for two out of 10 of the deaths during the first admission. The prognosis of the disease was negatively influenced by the worsening of liver dysfunction and the appearance of complications. The main predictors of mortality were infections, hepatic encephalopathy, variceal bleeding, and hepatorenal syndrome. Improving compliance and strict application of specific follow-up and treatment strategies could contribute to a better prognosis of patients with alcoholic liver cirrhosis.
Efficacy Comparison between Kegel Exercises and Extracorporeal Magnetic Innervation in Treatment of Female Stress Urinary Incontinence: A Randomized Clinical Trial
Authors: Mikuš Mislav , Kalafatić Držislav , Vrbanić Adam , Šprem Goldštajn Marina , Herman Mislav , Živković Njavro Marta , Živković Klara , Marić Goran , Ćorić Mario
Published: December 2022

Background and Objectives: To estimate the effectiveness of Kegel exercises versus extracorporeal magnetic innervation (EMI) in the treatment of stress urinary incontinence (SUI). Materials and Methods: A parallel group, randomized clinical trial was conducted in the Department of Obstetrics and Gynecology, Clinical Hospital Centre Zagreb, Croatia. After assessing the inclusion/exclusion criteria, each eligible participant was randomized to one of the two observed groups by flipping a coin: the first group underwent treatment with Kegel exercises for 8 weeks, while the second group underwent EMI during the same time interval. The primary outcome was the effectiveness of treatment as measured by the ICIQ-UI-SF overall score, eight weeks after the commencement of treatment. Results: During the study period, 117 consecutive patients with SUI symptoms were assessed for eligibility. A total of 94 women constituted the study population, randomized into two groups: Group Kegel (N = 48) and Group EMI (N = 46). After 8 weeks of follow-up, intravaginal pressure values in the EMI group were 30.45 cmH2O vs. the Kegel group, whose values were 23.50 cmH2O (p = 0.001). After 3 months of follow-up, the difference was still observed between the groups (p = 0.001). After the end of treatment and 3 months of follow-up, the values of the ICIQ-UI SF and ICIQ-LUTSqol questionnaires in the EMI group were lower than in the Kegel group (p < 0.001). Treatment satisfaction was overall better in the EMI group than in the Kegel group (p < 0.001). Conclusions: Patients treated with EMI had a lower number of incontinence episodes, a better quality of life, and higher overall satisfaction with treatment than patients who performed Kegel exercises.
Oxidative Stress and Inflammatory Biomarkers in Patients with Diabetic Foot
Authors: Vujčić Sanja , Kotur-Stevuljević Jelena , Vekić Jelena , Perović-Blagojević Iva , Stefanović Tatjana , Ilić-Mijailović Sanja , Koprivica Uzelac Branka , Bosić Srećko , Antonić Tamara , Guzonjić Azra , Mastilović Ana-Marija , Marković Zorica , Rizzo Manfredi
Published: December 2022

Background and Objectives: Diabetic foot (DF) development is driven by complex interactions of hyperglycemia, inflammation, and oxidative stress (OS). We aimed to investigate OS and inflammatory biomarkers in patients with DF and their potential to improve early diagnosis and management of DF. Materials and Methods: The prooxidant–antioxidant balance (PAB), superoxide dismutase (SOD), total oxidative status (TOS), total sulfhydryl groups (SHG), routine biochemical parameters, and complete blood count were determined in 42 patients with type-2 DM, of which 23 patients had DF, while 19 patients were without DF complications. The neutrophils-to-lymphocyte ratio (NLR) was evaluated as a biomarker of inflammation. Results: Patients with DF had significantly higher (p < 0.05) PAB levels (170 ± 33.9 U/L) compared to those without DF complications (142 ± 31.3 U/L). In addition, patients with DF had significantly reduced SOD activities (p < 0.01). NLR values were significantly higher in the DF group (median: 2.8; interquartile range: 2.0–4.3) than in the group without DF (median: 1.4; interquartile range: 1.4–2.1; p < 0.01). A positive correlation was found between the PAB and NLR index (r = 0.449; p < 0.05). The diagnostic accuracy of both PAB (AUC = 0.741; p < 0.01) and NLR (AUC = 0.760; p < 0.01) was estimated as acceptable. Conclusions: In conclusion, the development of DF is associated with enhanced OS and inflammation processes. PAB and NLR could be useful non-invasive biomarkers of DF development.
Urologic Complication after Laparoscopic Hysterectomy in Gynecology Oncology: A Single-Center Analysis and Narrative Review of the Literature
Authors: Capozzi Vito Andrea , Monfardini Luciano , Scarpelli Elisa , Barresi Giuseppe , Rotondella Isabella , De Finis Alessandra , Scebba Davide , Maglietta Giuseppe , Cianci Stefano , Ghi Tullio , Berretta Roberto
Published: December 2022

Background and Objectives: Minimally invasive surgery (MIS) has recently increased its application in the treatment of gynecological malignancies. Despite technological and surgical advances, urologic complications (UC) are still the main concern in gynecology surgery. Current literature reports a wide range of urinary tract injuries, and consistent scientific evidence is still lacking or dated. This study aims to report a large single-center experience of urinary complications during laparoscopic hysterectomy for gynecologic oncologic disease. Materials and Methods: All patients who underwent laparoscopic hysterectomy for gynecologic malignancy at the Department of Medicine and Surgery of the University Hospital of Parma from 2017 to 2021 were retrospectively included. Women with endometrial cancer, cervical cancer, ovarian cancer, uterine sarcoma, or borderline ovarian tumors were included. Patients undergoing robotic surgery with incomplete anatomopathological data or patients lost during follow-up were excluded from the analysis. Intraoperative and postoperative UC were analyzed and ranked according to the Clavien-Dindo classification. Results: Two hundred-sixty patients were included in the study: 180 endometrial cancer, 18 cervical cancer, nine ovarian cancer, two uterine sarcomas, and 60 borderline ovarian tumors. Nine (3.5%) UCs were reported (five intraoperative and four postoperative complications). No anamnestic variables showed a statistical correlation with the surgical complication in the univariable analyses. C1 radical hysterectomy, a higher FIGO stage, and postoperative adjuvant treatment (p-value = 0.001, p-value = 0.046, and p-value = 0.046, respectively) were independent risk factors associated with the occurrence of UC. Conclusions: The urological complication rates in patients with oncological disease are relatively rare events in the expert hands of dedicated surgeons. Radical hysterectomy, FIGO stage, and adjuvant treatment are independent factors associated with urinary complications.
Interaction between Dexamethasone, Ropivacaine, and Contrast Media Used in Interventional Pain Treatment: Considerations in Safety
Authors: Kim Yeon Ju , Kim Yeon-Dong , Kim Hyungtae , Ahn Dong Ji , Kim Ha-Jung , Koh Won Uk , Ro Young-Jin
Published: December 2022

Background and Objectives: Although epidural steroid injections are used as an effective treatment, this technique is associated with rare but serious ischemic complications, especially when particulate steroids are used. However, recent studies have reported that even if non-particulate steroids are used, particulates are formed by the interaction with some local anesthetics (LA), causing ischemic complications. This observational study evaluated commonly used combinations of non-particulate steroids and LA with contrast media via microscopic analysis and analyzed the chemical properties of each mixture to identify the correlation of particulate formation. Materials and Methods: Commonly used clinical non-particulate and particulate steroids, contrast media, and LA agent combinations were evaluated macroscopically and microscopically. The pH values were also measured at both room temperature (26 °C) and body temperature (36 °C). Where particulates were observed, the particulate size was measured. Results: Macroscopically, the mixture of non-particulate steroid and ropivacaine had a slightly cloudy appearance at all concentrations, but there was no visible particulate. However, when observed under a microscope, the pH-dependent particulate formation was observed at all concentration combinations tested. (0.1% ropivacaine: from 19 μm to 70 μm, and 0.2% ropivacaine: from 37 μm to 108 μm at room temperature (26 °C)). When contrast media was mixed or the temperature was raised to body temperature (36 °C), the number and size of the particulates decreased or dissolved. Conclusions: The combination of ropivacaine and dexamethasone, a non-particulate steroid, mainly used in epidural injections, forms particulates. However, when mixed with contrast media, particulates are dissolved because of changes in pH and factors affecting particulate formation. In fluoroscopy-guided injections, the use of contrast media could resolve particulate formation.
Structural Role of Plasma Membrane Sterols in Osmotic Stress Tolerance of Yeast Saccharomyces cerevisiae
Authors: Sokolov Svyatoslav S. , Popova Marina M. , Pohl Peter , Horner Andreas , Akimov Sergey A. , Kireeva Natalia A. , Knorre Dmitry A. , Batishchev Oleg V. , Severin Fedor F.
Published: December 2022

Yeast S. cerevisiae has been shown to suppress a sterol biosynthesis as a response to hyperosmotic stress. In the case of sodium stress, the failure to suppress biosynthesis leads to an increase in cytosolic sodium. The major yeast sterol, ergosterol, is known to regulate functioning of plasma membrane proteins. Therefore, it has been suggested that the suppression of its biosynthesis is needed to adjust the activity of the plasma membrane sodium pumps and channels. However, as the sterol concentration is in the range of thirty to forty percent of total plasma membrane lipids, it is believed that its primary biological role is not regulatory but structural. Here we studied how lowering the sterol content affects the response of a lipid bilayer to an osmotic stress. In accordance with previous observations, we found that a decrease of the sterol fraction increases a water permeability of the liposomal membranes. Yet, we also found that sterol-free giant unilamellar vesicles reduced their volume during transient application of the hyperosmotic stress to a greater extent than the sterol-rich ones. Furthermore, our data suggest that lowering the sterol content in yeast cells allows the shrinkage to prevent the osmotic pressure-induced plasma membrane rupture. We also found that mutant yeast cells with the elevated level of sterol accumulated propidium iodide when exposed to mild hyperosmotic conditions followed by hypoosmotic stress. It is likely that the decrease in a plasma membrane sterol content stimulates a drop in cell volume under hyperosmotic stress, which is beneficial in the case of a subsequent hypo-osmotic one.
Seeded Synthesis of AlPO4-5 Membrane in Diluted Mother Liquor
Authors: Wang Jing , Ji Chao
Published: December 2022

AlPO4-5 with an AFI topology membrane on an a-alumina substrate has been fabricated continuously, without defects, and with high intergrowth. By using traditional hydrothermal methods in diluted mother liquor, an AlPO4-5 membrane has been produced by a simple second growth synthesis. Scanning electron microscopy (SEM) revealed no defects in the prepared supporting film, and X-ray (XRD) diffraction confirmed the layer of molecular sieve AlPO4-5 on the porous support of α-alumina. In this study, various synthesis parameters were systematically examined. Based on H2, He, N2, CO2, and SF6 permeance results, the supported membranes display Knudsen diffusion behavior, and the membrane’s pervaporation properties of organic compounds (n-hexane, o-xylene, and TIPB) show minimized defects, verifying their high quality.
Electrochemical Performance and Conductivity of N-Doped Carbon Nanotubes Annealed under Various Temperatures as Cathode for Lithium-Ion Batteries
Authors: Zhong Zhengjun , Mahmoodi Soroosh , Li Dong , Zhong Shengwen
Published: December 2022

Nitrogen-doped carbon nanotubes (NCNTs) are obtained using a post-treatment method under different sintering temperatures. The catalysts can be removed from the Carbon Nanotubes (CNTs) within an acid treatment process. Then, the purified CNTs can be employed as a nitrogen doping basis. This research adds melamine as a nitrogen source during the sintering procedure under different temperatures to achieve NCNTs, which are applied to the cathodes. LiMn2O4 (LMO) cathode slurries are prepared using pristine CNTs and NCNTs samples as conductive additives. Coin cell lithium-ion batteries (LIBs) are fabricated using slurry samples. X-ray photoelectron spectroscopical analysis shows the nitrogen doping degree is up to 5 atom%, and graphitic-N nitrogen groups are the dominating species present on the NCNT’s surface while being treated at 800 °C. Graphitic-N nitrogen groups improve the conductivity and surface area of the NCNTs, which increases the rate capacity (106.8 mA h g−1 at 5 C) and cyclic retention (92.45% of initial capacity after 200 cycles at 5 C) of the lithium-ion batteries. The morphology of the NCNTs, the concentration of NCNTs elements, and the electrochemical performances of coin cell batteries are extensively discussed.
Understanding the Influencing Mechanism of CNTs on the Microstructures and Wear Characterization of Semi-Solid Stir Casting Al-Cu-Mg-Si Alloys
Authors: Wang Li , Zhang Zhenlin , Luo Yajun , Xiao Ying , Tan Fengliang , Liu Kecai
Published: December 2022

In this study, CNTs-reinforced Al-Cu-Mg-Si nanocomposites were successfully fabricated by high-energy ball milling (HEBM) combined with semi-solid stir casting. Then, the composites were subjected to hot extrusion. The Microstructure and Phase analysis of the CNT/Al-Cu-Mg-Si composites were characterized by an Optical microscope, Scanning Electron Microscope (SEM), and XRD. Additionally, density, hardness, and wear were measured. The results revealed that the addition of CNTs effectively inhibited the growth of α-Al grains, and the grains were dramatically refined. Additionally, the dynamic recrystallization degree of the composite extruded rod gradually increased from 1.3% to 68.4%, with the content of CNTs from 0 wt% to 3.0 wt%. The hardness values of the composite increased with an increase in CNTs. Moreover, the friction factor and wear rate of the composites first decreased and then increased as the content of CNTs increased. When 1.5CNTs were added, the friction coefficient (COF) and wear rate of composites reached the minimum of 0.3577 and 3.42 mg/km, which were reduced by 30.09% and 73.03% compared with Al-Cu-Mg-Si alloy, respectively.
A Creep Constitutive Model, Based on Deformation Mechanisms and Its Application to Creep Crack Growth
Authors: Zhang Jingwei , Li Jie , Zan Jingyi , Guo Zijian , Liu Kanglin
Published: December 2022

In this paper, a constitutive model, based on the creep deformation mechanism in P91 steel, under a wide range of stress levels, was established and embedded into finite element software. The accuracy and reliability of the model was verified by comparing the simulation of uniaxial creep tensile test results and the experimental data under different stress levels for P91 steel at 600 °C. The creep crack growth behavior of P91 steel, under a wide range of stress levels was simulated using a ductility-exhaustion-based damage model, combined with the stress-dependent creep ductility model, and the predicted creep crack growth (CCG) rates were compared with the experimental data. Finally, the established model was used to predict the CCG behavior for the pressurized pipes with axial surface cracks. The results show that the constitutive model, established on the basis of the creep deformation mechanism, agrees better with the experimental data than other constitutive models. The CCG rate varies at different direction angles θ for the axial surface cracks. The direction angle θ corresponding to the maximum creep crack length is about 33°, when the internal pressure exceeds 10 MPa. The initial crack shape (a0/c0) = 1, and it does not change with different initial crack depth ratios (a0/t). The established constitutive model can be well used in CCG life analyses and designs of high-temperature structures.
Progress and Perspective of Ultra-High-Strength Martensitic Steels for Automobile
Authors: Chen Hao , Zhao Linlin , Lu Shenghai , Lin Zhangguo , Wen Tong , Chen Zejun
Published: December 2022

With the background of emission peaks and carbon neutrality, light weight has become an irreversible trend in the development of the automobile industry. It is an inevitable choice to use a large amount of ultra-high-strength steels to realize light weight and safety of automobiles. Ultra-high-strength martensitic steels can be divided into hot-formed steels and cold-formed steels according to the forming process. In recent years, ultra-high-strength martensitic steels have been rapidly developed in automotive battery pack frameworks, door guard beams, bumpers, A-pillars, etc., depending on their good plasticity and advanced forming technology. In this paper, the recent progress of ultra-high-strength martensitic steels for automobiles is systematically reviewed, the mechanisms of alloying, strengthening, and toughening are emphatically expounded, and the hydrogen embrittlement problems in application are summarized. Finally, the prospects of manufacture and application of ultra-high-strength martensitic steels for automobiles in the future are forecasted.
Effect of Pre-Strain on Crack Growth Behavior of Zr702/TA2/Q345R Composite Plate
Authors: Zhou Binbin , Zhou Chao , Zhang Yawen , Chang Le , Zhou Changyu , Ye Cheng , Zhang Bojun
Published: December 2022

The influence of pre-strain on the fatigue crack growth behavior of Zr702/TA2/Q345R composite plate is studied by experiments and the finite element method. The crack perpendicular to the interface and the through-wall crack are considered at the same time. For the crack perpendicular to the interface, the monotonic plastic zone and cyclic plastic zone at the crack tip are used to study the influence of pre-strain on the plastic zone. Furthermore, the influence of pre-strain on the evolution of the plastic damage at the crack tip is analyzed in detail by studying the variation in the initial plastic energy and equivalent plastic strain. For the through-wall crack, the effect of pre-strain on the propagation behavior of cracks on both sides and the whole crack is studied systematically. The results show that the strengthening of the cracks on the Zr702 side is significantly higher than that on the Q345R side, so the inhibitory effect of pre-strain on the whole crack of the through-wall specimen is mainly due to the increase in the resistance to crack growth on the Zr702 side.