Specific Test Research Articles

Understanding the Impact of Childbirth: Postnatal Stress Symptoms in Psychologically Stable Mothers

We investigated the relationship between physical activity and perceived stress levels among pregnant women. A total of 28 pregnant women participated in the study. All participants completed psychological tests to assess stress levels and coping strategies. The physically active (PA) group consisted of 15 women aged 26-40, engaging in moderate physical activity for up to 120 minutes per week across two training sessions. The inactive (NA) group included 13 women aged 24-39 who did not exercise. Unpaired T-test analysis revealed no significant differences in stress-coping strategies between exercising and non-exercising women. However, two coping scales—problem-focused coping and emotion-focused coping—showed tendencies: physically active women leaned slightly more toward religious coping (p = 0.15), while non-physically active women favored restraint coping (p = 0.17). Overall, perceived stress levels did not differ significantly between the groups. The study highlights the importance of using specialized tests for pregnant women due to the unique context of pregnancy. Keywords: physical activity, pregnant women, stress, prenatal maternal stress

Videourodynamics - role, benefits and optimal practice.

Videourodynamics (VUDS) is an advanced diagnostic procedure that simultaneously combines functional and anatomical evaluation of the lower urinary tract. The goal of this synchronous assessment is to promote accurate diagnosis of the aetiology responsible for patient symptoms, improving therapeutic decision-making. Overall, high-quality VUDS is advocated when other tests such as traditional urodynamics might not provide sufficient data to guide therapy, particularly in patients with complex, persistent or recurrent dysfunctions of the lower urinary tract. Additionally, VUDS is often crucial in the follow-up monitoring of many patients with these dysfunctions. A VUDS study is frequently considered a gold standard in patients with neurogenic lower urinary tract dysfunction, female bladder outlet obstruction or congenital anomalies of the lower urinary tract. Nevertheless, this specialized test should be limited to patients in whom VUDS data add value. Particularly, reliable studies comparing the effect of diagnosis with and without imaging on management outcomes are lacking, and no standardized procedures for undertaking VUDS are available. Additionally, patients should be carefully selected for VUDS evaluation, considering the increased cost and risks associated with radiological imaging. In routine practice, clinicians should balance the additional value of synchronous imaging and the enhanced diagnostic precision of VUDS against the limitations of this approach, which mainly include an uncertain effect of VUDS on final treatment outcomes.

A Framework for Best Practices and Readiness in the Advent of Anti-Amyloid Therapy for Early Alzheimer's Disease in Asia.

Advances in biomarker-based diagnostic modalities, recent approval of anti-amyloid monoclonal antibodies for early Alzheimer's disease (AD; mild cognitive impairment or mild dementia due to AD) and late-stage clinical development of other disease-modifying therapies for AD necessitate a significant paradigm shift in the early detection, diagnosis and management of AD. Anti-amyloid monoclonal antibodies target the underlying pathophysiological mechanisms of AD and have demonstrated a significant reduction in the rate of clinical decline in cognitive and functional outcome measures in patients with early AD. With growing recognition of the benefit of early interventions in AD, an increasing number of people may seek diagnosis for their subjective cognitive problems in an already busy medical system. Various factors such as limited examination time, lack of expertise for cognitive assessment and limited access to specialized tests can impact diagnostic accuracy and timely detection of AD. To overcome these challenges, a new model of care will be required. In this paper, we provide practical guidance for institutional readiness for anti-amyloid therapies for early AD in Asia, in terms of best practices for identifying eligible patients and diagnosing them appropriately, safe administration of anti-amyloid monoclonal antibodies and monitoring of treatment, managing potential adverse events such as infusion reactions and amyloid-related imaging abnormalities, and cross-disciplinary collaboration. Education and training will be the cornerstone for the establishment of new pathways of care for the identification of patients with early AD and delivery of anti-amyloid therapies in a safe and efficient manner to eligible patients.

Locating Insulation Defects in HV Substations Using HFCT Sensors and AI Diagnostic Tools.

In general, a high voltage (HV) substation can be made up of multiple insulation subsystems: an air insulation subsystem (AIS), gas insulation subsystem (GIS), liquid insulation subsystem (power transformers), and solid insulation subsystem (power cables), all of them with their grounding structures interconnected and linked to the substation earth. Partial discharge (PD) pulses, which are generated in a HV apparatus belonging to a subsystem, travel through the grounding structures of the others. PD analyzers using high-frequency current transformer (HFCT) sensors, which are installed at the connections between the grounding structures, are sensitive to these traveling pulses. In a substation made up of an AIS, several non-critical PD sources can be detected, such as possible corona, air surface, or floating discharges. To perform the correct diagnosis, non-critical PD sources must be separated from critical PD sources related to insulation defects, such as a cavity in a solid dielectric material, mobile particles in SF6, or surface discharges in oil. Powerful diagnostic tools using PD clustering and phase-resolved PD (PRPD) pattern recognition have been developed to check the insulation condition of HV substations. However, a common issue is how to determine the subsystem in which a critical PD source is located when there are several PD sources, and a critical one is near the boundary between two HV subsystems, e.g., a cavity defect located between a cable end and a GIS. The traveling direction of the detected PD is valuable information to determine the subsystem in which the insulation defect is located. However, incorrect diagnostics are usually due to the constraints of PD measuring systems and inadequate PD diagnostic procedures. This paper presents a diagnostic procedure using an appropriate PD analyzer with multiple HFCT sensors to carry out efficient insulation condition diagnoses. This PD procedure has been developed on the basis of laboratory tests, transient signal modeling, and validation tests. The validation tests were carried out in a special test bench developed for the characterization of PD analyzers. To demonstrate the effectiveness of the procedure, a real case is also presented, where satisfactory results are shown.

KAJI NUMERIK GROUND PAD SHOE KENDARAAN TEMPUR DENGAN MODEL MATERIAL HYPERELASTIC

One of the important components on a combat vehicle is the ground pad shoe (GPS) or track pad. GPS that has been developed at this time mostly uses rubber material. Rubber raw materials themselves are found in Indonesia in large amount. Indonesia left 3 million tonnes of natural rubber unprocessed in 2018. On the other hand, natural rubber research is quite expensive and takes a long time to become a product. To make rubber products is needed special molds and tests. To solve the high costs and long time involved in rubber research, it is necessary to carry out numerical research. In this study, a numerical study of GPS rubber for combat vehicles was carried out with a hyperelastic material model. The research was conducted experimentally and numerically. Tensile testing is carried out on imported GPS samples which are then used as comparison data for numerical studies. The Mooney-Rivlin, Neo-Hookean, Yeoh, and Ogden hyperelastic models were varied to get the stress and strain values ​​closest to the experimental test. The results of the numerical study show that the best hyperelastic model for the imported GPS rubber model is the Neo-Hookean model. The tensile strength of GPS according to the experimental tensile test results is 16.93 MPa, while the result of the finite element method (FEM) is 16.75 MPa. The GPS modulus 200% according to the experimental tensile test results is 14.7 mm/mm, while the FEM result is 15.3 mm/mm. The difference between the FEM and experimental test values ​​for tensile strength and modulus 200% are below 5%. Maximum stress on GPS is 4,4 MPa and safety factor 3,8.

Exploring the Relationship between CD66c Expression and Clinico-Haematological Parameters in Pediatric B-Cell Acute Lymphoblastic Leukemia (ALL)

Background: Pediatric B-cell Acute Lymphoblastic Leukemia presents with diverse clinical and hematological manifestations. Understanding these characteristics is crucial for effective management and prognostication.  Methods: This study conducted as prospective observational study at Lady Hardinge Medical College and Kalawati Saran Children Hospital, New Delhi, from November 2017 to March 2019. This study enrolled 30 pediatric patients with B-cell ALL who underwent comprehensive evaluations including routine and specialized hematological tests, bone marrow aspiration (BMA), cytochemistry, and immunophenotyping. Clinical features, hematological parameters, and CD66c expression on lymphoblasts were assessed.  Results: Immunophenotyping revealed that 28 cases (93.3%) were CALLA positive (CD10 positive), while 2 cases (6.7%) were CALLA negative (CD10 negative). The age ranged from 1.5 to 12 years, with a 2:1 male to female ratio. The mean age was 4.8 years.. Common presenting complaints included fever (93.3%) and pallor (60.0%). Hepato-splenomegaly (60.0%) and lymphadenopathy (60.0%) were the most frequent clinical findings. Hematological findings showed moderate to severe anemia (mean hemoglobin 7.19 g/dL), with 56.7% of patients having hemoglobin levels between 4.0-7.9 g/dL. Leukocytosis (>10,000/cumm) was observed in 53.3% of cases, with 20% having total leukocyte counts >50,000/cumm. Thrombocytopenia (platelet count ≤ 25,000/cumm) was noted in 56.7% of patients. Immunophenotyping revealed CD66c expression >20% gated in 46.7% of cases, correlating with more severe clinical features and poorer hematological parameters.  Conclusion: Pediatric B-cell ALL exhibits a spectrum of clinical and hematological features. Elevated CD66c expression correlates with aggressive disease presentation and worse clinical outcomes, suggesting its potential utility as a prognostic marker. Early identification of these parameters can aid in risk stratification and tailored therapeutic approaches.

КОНСТРУКТОРСКО-ТЕХНОЛОГИЧЕСКОЕ ОБЕСПЕЧЕНИЕ ТРИБОТЕХНИЧЕСКИХ ПАРАМЕТРОВ СОЕДИНЕНИЙ ТРЕНИЯ СКОЛЬЖЕНИЯ В ПРОЦЕССЕ ПРИРАБОТКИ ПРИ СТУПЕНЧАТОМ НАГРУЖЕНИИ

The paper deals with the issues of technological support to provide the load capacity index of cylindrical sliding friction joints during running-in under step stress. The load capacity of sliding friction joints is one of the tribological characteristics, depending on design and technological factors. The results of studying tribotechnical characteristics of cylindrical sliding friction pairs operating under boundary friction conditions are presented. The working surfaces of these triboelements after preliminary finishing (turning with composite 10 or grinding with the periphery of an abrasive wheel) were subjected to various technological methods of antifriction treatment. In particular, the following methods are considered: 1) application of break-in soft films on the surface of triboelements (shafts) by plating methods; 2) application of break-in soft copper-containing films on the surface of the triboelement (shafts) by friction brassing or chemical copper plating; 3) modification of the surfaces of triboelements with solid nitride-containing coatings (combined treatment) in combination with soft break-in films followed by finishing and hardening surface treatment by surface plastic deformation methods. The shafts were made of 45 steel with subsequent hardening, and the inserts were made of bearing materials recommended in the reference literature (antifriction cast iron ASF-1; babbit B -88; bronze BrOCC -5-5-5 ). Logical models of antifriction treatment methods under consideration and the rationale for their application are presented. Experimental studies were carried out by methods of active experiment on a special test bench having a wide range of changes in stresses on the model of the tested compound and relative sliding velocities of triboelements. Statistical treatment of experimental results made it possible to find out the influence of the studied design and technological factors and running-in conditions on the tribotechnical characteristics of the compounds. The research results are analyzed and on their basis practical recommendations for their use are given. Adequate models of forming the load capacity of joints are obtained, which are recommended to be taken into account at the stages of their design (selection of materials and coatings), machining and running-in.

Power overwhelming: the one with the oscilloscopes

Visualization as a discipline has to investigate its practical implications in a world steadily moving toward greener computing methods. Quantifying the power consumption of visualization algorithms is thus essential, given the ever-increasing energy needs of GPUs. Previous approaches rely on integrated sensors or invasive methods that require modifications and special test setups. However, they still suffer from imprecision from low sampling rates and integration over time. Using a high-precision, high-frequency setup via steerable oscilloscopes, we can objectively measure the resulting quality of previous approaches. This is essential to establish a ground truth, pave the way for improved modeling of power consumption in general, and enable better estimates based on the output of lower-quality sensors. We finally discuss benefits that can be drawn from the additional insight of the higher-precision setup and which additional use cases can justify the incurred costs.Graphical abstract

The Influence of Weld Interface Characteristics on the Bond Strength of Collision Welded Aluminium-Steel Joints.

Collision welding is a promising approach for joining conventional materials in identical or dissimilar combinations without heat-related strength loss, thereby opening up new lightweight potential. Widespread application of this technology is still limited by an insufficient state of knowledge with respect to the underlying joining mechanisms. This paper applies collision welding to a material combination of DC04 steel and EN AW 6016 aluminium alloy. Firstly, the welding process window for the combination is determined by varying the collision speed and the collision angle, the two main influencing variables in collision welding, using a special model test rig. The process window area with the highest shear tensile strength of the welded joint is then determined using shear tensile tests and SEM images of the weld zone. The SEM investigations reveal four distinct metallographic structures in the weld zones, the area fractions of which are determined and correlated with collision angle and shear tensile strength.

Eagle’s syndrome: Modern systematic review and presentation of radiographic cases

Introduction: The styloid process is a bony structure of the base of the skull, which can undergo pathological structural changes. So, its elongation may possibly provoke Eagle’s syndrome, also known as stylohyoid syndrome, which is a head and neck pathological condition that rarely manifests with severely painful symptomatology. Objective: The present literature review aims to deal with the understanding of the pathophysiology, as well as the investigation of the diagnostic and therapeutic facts regarding Eagle’s syndrome. Materials – Methods: An extended research of modern literature through papers published in scientific journals has been conducted, deploying the databases PubMed and Google Scholar. Results: Eagle’s syndrome is a rare pathological condition, whose prevalence is approximately 4% of general population. In the literature, several pathogenetic patterns have been reported and they are divided into acquired and idiopathic biochemical mechanisms. In order to diagnose the disease, one should take the painful symptoms referred by the patient into consideration, in conjunction with specific clinical tests. However, the final diagnosis is set after the radiological evaluation. Eagle’s syndrome manifests with non-specific symptomatology, thus it should be differentiated from other diseases and conditions of the head and neck anatomical area. Regarding the therapy of the syndrome, a vast range of conservative choices is available nowadays, mainly basedon drugs, while at the same time there are surgical techniques with comparatively better long-term outcome. Conclusions: There is an expressively increased interest, regarding the diagnosis and the therapeutics of Eagle’s syndrome. Modern medical sciences attempt to gradually advance the diagnostic methodology and constantly improve the therapeutic choices of this disease. The ultimate purpose is the more effective management of the patients and the enhancement of their life quality.

Effect of multiple injection optimization on combustion characteristics of low-pressure EGR system engine

Abstract In recent years, reducing oil consumption and pollutant discharge in transportation industry has become an important measure to alleviate energy crisis and environmental pollution. Therefore, the fuel economy and emission characteristics of the engine have become an important index to evaluate the quality of an engine, so EGR technology has gradually become the standard of gasoline engines. But EGR is not always good. In order to alleviate the adverse effects of EGR on combustion, further research on engine combustion is needed. In order to study the effect of multiple injection strategy on engine combustion characteristics, this paper takes a high pressure direct injection gasoline engine equipped with low pressure EGR system as the research object, and verifies the designed multiple injection strategy on special test equipment. A large amount of combustion data of the engine under the same load, different fuel injection stages and fuel injection ratios were collected. By comparing the evaluation indexes of main pollutant emission, fuel consumption and combustion stability, it is found that with the increase of injection times, the combustion characteristics and knock of the engine show a trend of improvement. After using multiple injection strategies at 2000r/min, it can be seen that the optimized injection strategy has better emission characteristics and lower fuel consumption lower knock intensity than that before the injection mode optimization without affecting the power performance.

Online motion accuracy compensation of industrial servomechanisms using machine learning approaches

This paper addresses the crucial aspect of position error modeling and compensation in industrial servomechanisms with the aim to achieve accurate control and high-performance operation in industrial robots and automated production systems. The inherent complexity and nonlinear behavior of these modules, usually consisting of a servomotor and a speed reducer, often challenge traditional analytical modeling approaches. In response, the study extensively explores the design and implementation of Machine Learning (ML) algorithms to obtain a comprehensive model of the Transmission Error (TE) in rotating vector reducers, which is a main source of robot motion accuracy errors. The ML models are trained with experimental data obtained from a special purpose test rig, where the reducer is tested under different combinations of input speed, applied load and oil temperature. In the second part of the work, the resulting predictive model, tailored to capture the intricate dynamics of the analyzed reducer, is imported into a programmable logic controller to enable online compensation strategies during the execution of custom motion profiles. Experimental tests are conducted using two distinct motion profiles: one generated with a cycloidal law, typical of industrial machinery, and the other extrapolated from the joints of an industrial robot during a pick-and-place task. The results demonstrate the effectiveness of the proposed approach, enabling accurate prediction and substantial reductions (over 90%) in the overall reducer TE through the implemented predictive model.

Issues of ensuring the resistance of high-voltage solar arrays of spacecraft to the effects of secondary arc discharges

We have considered the issues of ensuring the resistance of high-voltage solar battery (SB) of spacecraft to the effects of secondary arc discharges. Research in this area has been going on for more than 50 years, but the answer to all the questions has not yet been found. First of all, this is due to the complexity of the electrophysical processes occurring on the surface of the spacecraft in space and in laboratory conditions. The second reason is the random nature of secondary vacuum arc discharges, which requires the use of special test methods to confirm the effectiveness and reliability of selected design and technological solutions. Tests in conditions close to full-scale conditions do not allow us to solve this problem. We have given a retrospective review of publications on the physical features of secondary arcs arising on SB of spacecraft, the mechanisms of their initiation, experimental research and testing methods. We paid considerable attention to the issues of the occurrence of secondary arc discharges SB of the spacecraft in the conditions of ionospheric plasma and plasma generated by electric propulsion thrusters. We have shown that despite the large amount of accumulated data and knowledge, the transition from low-voltage SB to high-voltage SB remains a difficult scientific and technical problem, which requires additional research to solve. In addition, it is already necessary to start training personnel who possess a wide range of knowledge and are able to work on this topic. To do this, it seems advisable to organize sectoral research, as well as the allocation of targeted funds for the training of highly qualified specialists and their independent research. This approach will make it possible to solve the problem of creating high-voltage SB in the shortest possible time and prepare personnel for the development of this technology.

Special Exercises to Develop Some Visual Abilities and Defensive Movement Skills for Players of the Middle Euphrates Education Handball Teams

The purpose of this paper is to preparing special exercises to develop some visual abilities and the skill of defensive movements for the players of the educational teams of the Middle Euphrates in handball, preparing tests for some visual abilities for the players of the educational teams of the Middle Euphrates in handball, and identifying some visual abilities and defensive movement skills of players of the Middle Euphrates handball teams. The research objectives addressed by the researchers are what determine the nature of the method used, so the researchers used the experimental method in the style of two equivalent groups (control and experimental) with pre- and post-tests to suit the research objectives. The research community was determined by handball players for the teams of the Middle Euphrates region's education affiliated to the general education directorates in the governorates, distributed according to the governorates (Karbala, Najaf, Babylon, Muthanna, Diwaniyah), totaling (150) players. The research sample was chosen randomly and represented the players of the Karbala Education team affiliated to the holy Karbala Governorate, numbering (30) players who represent if the goalkeepers were excluded due to the specificity of the exercises, numbering (2) and (4) players were absent from performing the exercises, and the total number of the sample became (24) where they were randomly divided into two equal groups (control and experimental) with (12) players for each group, thus representing the research community, its sample and the percentage. The exploratory sample was 8 players from the Education of Babylon Governorate. One of the most important results reached by the researcher is that: The tests prepared by the researchers gave real results for visual abilities in handball, and the special exercises contributed to developing visual abilities and the skill of various defensive movements better among the members of the experimental group. One of the most important recommendations recommended by the researchers is that: Necessity of using special exercises to develop special visual abilities and the skill of defensive movements that were not studied with the same sample and other samples, and preparing special tests for visual abilities for each game according to the nature of its performance and needs

EXPERIMENTAL VERIFICATION OF PREDICTED FAILURES IN THE USE OF RUSSIAN VERB TYPES BY CHINESE STUDENTS

In Chinese, verb aspect is expressed by verbs in combination with various linguistic means. Based on the difference between the verb aspect system of Russian and Chinese languages and the possible expressions of verb aspect in Russian, this paper aims to predict possible errors in the use of Russian verb aspect. In order to check the correctness of our analysis, a special diagnostic test was conducted. The test results show that the errors made by Chinese students primarily do not stem from the influence of their native language, but from the fact that students are not able to assess the situation, cannot find or even see certain reference points, available signals, directly indicating the use of this or that verb aspect. Errors are explained by elementary ignorance of the verb forms, especially in such cases as брать — взять, ловить — поймать and ignorance of the formation of the verb form itself, for example, the formation of the imperative form, etc. This is the result of insufficient training of students. In this case, the problem is not in students, but, firstly, in the complexity of the topic itself, and, secondly, in the method of teaching. We believe that it is necessary to give students a clear scheme of verb aspect meanings and identify those signals that can help students choose the type of a verb adequate to the situation of communication; the course of studying the verb aspect should be long enough, because strong and stable skills of the correct use of verb aspect are formed only as a result of gradual and regular work on the types of the verb, made over a long period of time. The results of this work can also serve as a starting point for determining not only the content of verb types teaching exercises, but also for developing methodological recommendations for them.

Recoverable and plastic strains generated by forward and reverse martensitic transformations under external stress in NiTi SMA wires

Although superelastic NiTi shape memory alloy wire displays very high resistance to plastic deformation in austenite and martensite phases, incremental plastic strains are recorded whenever the cubic to monoclinic martensitic transformation (MT) proceeds under external stress leading to functional fatigue degradation. Therefore, special closed-loop thermomechanical loading tests were performed to shed light on the mechanism by which the incremental plastic strain are generated. These tests revealed that both forward and reverse MTs occurring above certain stress thresholds generate plastic strains specific for the [temperature, stress] conditions under which the MTs occurred. While the forward MT upon cooling does not produce plastic strain or permanent lattice defects up to 500 MPa stress, the reverse MT upon heating starts to generate them from 100 MPa. While plastic strain generated by the forward MT merely elongates the wire, plastic strain generated by the reverse MT also reduces the recoverable strain. Since the reverse MT upon heating generates plastic strains at lower external stresses than the forward MT upon cooling, it is largely responsible for cyclic instability of NiTi actuators. The characteristic thresholds and magnitudes of plastic strains generated by the forward and reverse MTs define the functional fatigue limits for specific NiTi wires.

Digital transformation of enterprises empowers the development of new productive forces of enterprises

Based on the data of financial statements of A-share listed companies from 2015 to 2022 and ESG index data of Huazheng Company, this paper empirically analyzes the effect and mechanism of digital transformation on the new quality productive forces of enterprises. The results show that digital transformation can significantly promote the improvement of the new quality productive forces of enterprises, and the results are still valid after dealing with endogenous problems, eliminating special years and changing cluster test. Heterogeneity analysis shows that from the perspective of enterprise nature, the digital transformation of state-owned enterprises and high-tech enterprises has a more significant role in promoting the new quality productive forces of enterprises. The mechanism research shows that digital transformation can promote ESG practice of enterprises, and then promote the improvement of new quality productive forces level of enterprises. Therefore, it is proposed to accelerate the green transformation of enterprise development mode, promote the digital transformation of enterprises and corporate social responsibility governance by institutional supply, and strengthen the empowerment effect of internal governance of digital technology, hoping to provide useful reference for the development of new quality productive forces of enterprises.

Dynamic swatch testing of liquid aerosols in a laboratory-sized recirculating wind tunnel

Chemical warfare agents (CWAs) pose a threat as gaseous substances and as liquid aerosols, necessitating chemical warfare-protective clothing for soldiers. The paramount consideration lies in the effectiveness of the clothing as a barrier against the pertinent CWAs. This paper presents a dynamic swatch test method aimed at evaluating the performance of such clothing against liquid-phase aerosol penetration. Central to the methodology is a specialized test cell designed to rotate to the left and right, integrated within a laboratory wind tunnel, replicating mission-relevant conditions with varying wind speeds. Utilizing di(2-ethylhexyl) sebacate particles as liquid aerosols, tests were conducted at wind speeds of 1.0, 3.0, and 5.0 m/s. Penetration assessment relied on analyzing particle counts downstream and upstream of the fabric, with preliminary studies showing that higher wind speeds and fabric air permeabilities increase penetration at an equivalent face velocity of 5.0 cm/s. Interestingly, penetration decreased when fabric samples were subjected to rotation. The system and methodology devised demonstrated consistent and repeatable results, offering valuable insights into optimizing the effectiveness of chemical warfare-protective clothing. This research contributes to advancing methodologies for testing protective clothing, crucial for ensuring the safety of military personnel in hazardous environments.

Guided Wave Behavior in Type IV Composite Overwrapped Pressure Vessels Under Fatigue Loading

Innovative Ultrasonic Guided Wave Approach for Structural Health Monitoring of Type IV Composite Overwrapped Pressure Vessels Seyedreza Hashemi, Jan Heimann, Amir Charmi, Eric Duffner, Jens Prager Abstract: The digitalization of quality control processes and the use of digital data infrastructures is a novel idea that can be applied for ensuring the operational safety and reliability of pressure vessels, particularly in the context of hydrogen storage at high pressure. Despite the critical role these pressure vessels play, current safety regulations lack an established concept for Structural Health Monitoring (SHM). This research addresses this gap by presenting a study on the application of ultrasonic guided waves (GWs) for SHM of Type IV Composite Overwrapped Pressure Vessels (COPVs). The study focuses on the development of a reliable measurement system to transition from conventional periodic inspections to SHM and predictive maintenance, prolonging the remaining lifetime of the vessels. A sensor network is employed, consisting of fifteen piezoelectric wafers arranged in three rings, which are mounted on the outer surface of the COPV. Deploying GWs, known for their long-distance propagation and ability to cover complex structures, the study explores GW behavior under different environmental and operational conditions, including periodic pressure fluctuations and temperature loadings. Meticulous analysis of GW signals by utilizing various features and damage indices, underscores their suitability for an effective SHM under realistic working conditions. The project aims to localize defects by considering temperature, and internal pressure. Mimicking the continuous monitoring of Type IV COPVs in H2 refueling gas stations under authentic operational conditions, the COPV underwent thousands of pressure load cycles in our special test facility . The implemented methodology facilitates early damage detection, showcasing the efficacy of the designed method in effective safety assurance.

The Prediction of Failure in the Gas Filtration System in Low-Pressure Carburising Furnaces

Predictive maintenance is one of the key aspects of Industry 4.0. The article presents the results of experimental tests of nitrogen purification filters in the installation of a low-pressure, metal processing device. The aim of the research was to develop a predictive algorithm for making decisions regarding the replacement of used filters, based on flow analysis and measurement of the pressure difference in front of and behind the tested filter. For the purposes of the research, a special test stand was constructed, which made it possible to determine the operating characteristics of three selected filters. Based on the tests carried out, the limit characteristics of the parameters measured were determined, identifying the need to replace filters in the gas installation.