Life Test Research Articles

Konsep Etika Keutamaan dalam Tasawuf Abdul Qadir Al-Jailani dan Pengaruhnya terhadap Terbentuknya Akhlak Manusia

This study aims to explore the concept of ethical virtue in the teachings of Sufism of Abdul Qadir al-Jailani and its relevance in the formation of modern human character. According to al-Jailani, purification of the soul is a key element in achieving moral perfection. This process consists of several spiritual stages, namely repentance, which means returning to Allah with regret and determination to improve oneself; zuhud, freeing oneself from worldly attachments; tawakal, which is surrendering oneself completely to the will of Allah; patience, being steadfast in facing all life's tests; honesty, behaving according to the truth; gratitude, always being grateful for all the blessings given; and ridha, accepting all His decisions sincerely. These stages aim to improve individual morals and guide them towards a better life spiritually and ethically. This study uses a library research method with a qualitative approach, in which content analysis techniques are applied to comprehensively understand al-Jailani's teachings. The results of the study indicate that the concept of ethical virtue taught by al-Jailani is very relevant in the development of human character, both in the past and the present. His teachings can be integrated into the modern ethical and moral education system as an effort to form individuals with noble morals. The appreciation of these values allows humans to live more meaningfully, have good morals, and contribute to creating a more dignified society. In facing modern moral challenges, such as materialism and individualism, al-Jailani's teachings can be a relevant and sustainable ethical guide.

Inferences of accelerated generalized type-I hybrid censoring data under power hazard rate population

In reliability engineering or medical studies, more information about the life expectancy of products or materials is needed. This information under use conditions is more difficult to collect especially under highly reliable case. In this paper, the problem of statistical inference when the lifetime of a product or material has the power failure rate distribution is developed. To save the cost and time induced by units the experiment is designed with respect to partially step-stress accelerated life tests (ALTs) with type-I generalized hybrid censoring scheme (GHCS). The point estimate of the model parameters as well as the accelerated factor are obtained with respect to the maximum likelihood (ML) and Bayes methods. Also, the asymptotic normal properties of ML estimates, two bootstrap techniques and Markov Chain Monte Carlo techniques are used to formulate interval estimators. A real lifetime data set is used to illustrate the application of the proposed model. Finally, a Monte Carlo simulation study is constructed to discuss and assess, the proposed model and estimation methods.

Reliability Assessment for Dual Constant‐Stress Accelerated Life Test Based on Weibull Distribution With Type‐II Censoring

ABSTRACTAccelerated life test (ALT) is a generally feasible and effective approach for evaluating the reliability of highly reliable products at normal operating conditions. This paper considers the reliability assessment for a dual constant‐stress ALT with Type‐II censoring for the Weibull distribution with constant shape parameter and a log‐linear link between the scale parameter and the stress factors. We derive the maximum likelihood estimates, weighted least squares estimates using a certain random variable transformation, and a combined maximum likelihood‐least squares estimates for the unknown parameters. In addition, we construct confidence intervals for the parameters of interest using both asymptotic theory and parametric bootstrap technique. Finally, simulation studies and an illustrative example are presented to demonstrate the effectiveness and feasibility of the proposed methods.

A Bayesian-interference approach to quantify degradation parameters in a water-cooled variable speed screw compressor chiller

Abstract Variable-speed screw chillers can provide effective capacity modulations in commercial buildings to reduce energy consumption, match the load requirements, and contribute to lower equivalent carbon emissions. However, variable-speed operation can also yield to degradation phenomena inside the compressor. Assessing the real-time health status of chillers and detecting anomalies are important aspects to ensure long-term operation and improve reliability. To this end, an automated accelerated life test (ALT) procedure was developed and applied to a 513 kW (145.9 RT) water-cooled variable-speed screw chiller in a laboratory test facility to experimental assess performance degradation over time. After every 1,000 operating hours of ALT, steady-state performance tests at 30%, 50%, 75% and 100% load were conducted according to AHRI Standard 550/590. Additional operating conditions were included while conducting the tests to provide a more complete assessment of the degradation trends compared to the initially measured baseline. The experimental data set was then used to quantify the performance degradation based on the impact on the screw compressor operation. A Bayesian-inference identification approach has been developed to identify changes of sensitive parameters that statistically provide evidence for the likelihood of a performance degradation of the compressor. The information was used to implement the parameters in a dynamic model which was used to perform studies to predict the degradations of a chiller. The outcomes of this study help to improve the maintenance schedule of a compressor and even the whole chiller so that the system can be operated more economically and unplanned downtime can be minimized.

Study on stress concentration and fatigue life of tubing with slip indentation

The indentation caused by slip on the outer wall of tubing is a significant contributor to stress concentration and, consequently, fatigue failure in the tubing string. Through an analysis of the interaction between slips and tubing, a mathematical model to predict slip-tubing interaction and slip crushing load is formulated, accounting for external pressure, internal pressure, and axial forces. On this basis, the influence factors and influence rules of slip crushing load are studied, and three-dimensional yield surface and tri-axial stress ellipse of tubing are investigated, considering different transverse load factors and design factors. To accurately forecast the fatigue life of tubing subjected to slip indentation, two models are established: one for fatigue life prediction and the other for tubing string vibration. In order to quantitatively assess the stress concentration arising from slip indentation, a finite element model of tubing featuring slip indentation is established. Finite element analysis reveals that stress concentration and non-uniformity are evident in the vicinity of slip indentation, with their severity intensifying as the indentation depth grows. The initial step in assessing fatigue life involves fatigue life tests on tubing material subjected to varying stress levels. Subsequently, a case study is conducted and the variations of wellhead pressure and axial stress are evaluated. Fatigue life analysis reveals that the fatigue life is notably sensitive to variations in stress amplitude and slip indentation depth. An increase in the magnitude of alternating stress and the depth of slip indentation will result in a significant reduction in the fatigue lifespan. The methodologies employed in this research, along with the resulting findings, offer a robust theoretical framework and a solid practical basis for forecasting and managing stress concentration and fatigue durability in tubing affected by slip indentation.

Comparing experimental designs for parameterizing semi-empirical and deep learning-based lithium-ion battery aging models

Design of Experiment (DOE) methods can be applied to optimize test plans of cycle life aging studies with the aim to efficiently parameterize lithium-ion battery aging models. Since different DOEs exist and their effect on the prediction performance of battery aging models has not yet been investigated, we conducted a cycle life aging study with six commonly used DOEs (One-factor-at-a-time, Taguchi, Box–Behnken, Central Composite, Full Factorial, and D-optimal) and compare their influence on the prediction performance of a semi-empirical and a deep learning-based battery aging model. The results show that the semi-empirical model benefits the most from statistically optimized test plans. Compared to randomly selecting test plans, applying DOE methods helps to consistently achieve one of the lowest possible prediction errors for a given number of test points. Furthermore, it is shown that a D-optimal test plan and the test plans obtained from response surface methods (Box–Behnken and Central Composite) require only half as many test points as a Full Factorial test design, but still result in semi-empirical models with a high prediction accuracy that is similar to the Full Factorial test design. In contrast, deep learning-based battery aging models benefit significantly less from statistically optimized test plans. The highest prediction accuracy is achieved by the Full Factorial test plan and all other DOEs result in higher prediction errors and are even outperformed by several randomly defined test plans. Instead of using static designs, deep-learning-based models profit from a dynamic test optimization, which reduces the number of tested batteries during cycle life testing based on their information gain. We demonstrate that with our proposed dynamic test reduction algorithm, which analyzes the information gain based on aging features extracted after 100 EFC of cycling, up to 50% of all tested batteries of a Full Factorial test plan can be excluded from the cycle life study without deteriorating the prediction accuracy of the resulting deep learning-based battery aging model.

On prediction of future failure times based on bathtub-shaped type-II censoring samples

In this paper, we focus on predicting future failure times under Type-II right censoring samples with bathtub-shaped failure times. We first discuss the point and interval estimation of the unknown parameters using the maximum likelihood estimation and spacing-based methods. Various point predictors for future failure times are derived, using the best unbiased, maximum likelihood, conditional median, and median unbiased methods. Moreover, we establish the corresponding prediction intervals by applying different techniques including pivotal, Wald, highest conditional density, and shortest length methods. A simulation study is performed to assess the performance of the proposed prediction methods. Additionally, two real datasets are analyzed: one representing the survival times of patients treated for stomach cancer (Hand et al., 1994) and another from Lawless (2011), showing the duration in thousands of cycles until electrical appliances failed in a life test. These analyses illustrate the practical application of the proposed methods. Based on these numerical experiments, it is shown that the maximum likelihood predictor based on two-stage procedure and the conditional median predictor are the best point predictors for future failure times. Moreover, the highest conditional density method is identified as a strong candidate for establishing prediction intervals.

The Role of Artificial Intelligence in Modern Software Engineering

Abstract. The rapid advancement of Artificial Intelligence (AI) has significantly influenced various industries, including software engineering. This paper explores the integration of AI into software engineering, focusing on its applications across different stages of the software development life cycle, including design, development, testing, project management, and maintenance. AI's ability to automate tasks, enhance efficiency, and improve code quality is revolutionizing how software is built and maintained. The paper also addresses the challenges and risks associated with AI-driven software engineering, such as dependency on AI tools, ethical concerns, and security vulnerabilities. Finally, the paper highlights future trends in AI-powered software engineering, including adaptive and self-healing systems, AI-enhanced collaboration, and full software automation. The role of AI in shaping the future of software engineering is both profound and transformative, making it a critical area of study.

Optimal Constant-Stress Accelerated Life Tests for the Marshall-Olkin Extended Lindley Distribution under Complete Sampling

This study introduces an extended Lindley distribution utilizing a new family of Marshall-Olkin distributions, providing a more flexible framework for modeling lifetime data. The distribution is examined within the context of complete sampling for k-level constant stress accelerated life testing. A reliability analysis of the proposed model and a discussion on parameter estimation using maximum likelihood estimation are presented. Asymptotic confidence intervals for the parameters are derived through the Fisher information matrix. Bayesian estimation procedures and the Markov Chain Monte Carlo (MCMC) approach are also explored. Real data is analyzed to assess the model’s fit, followed by simulation studies to illustrate its performance. The paper concludes with a summary of findings and implications for future research.

The Effect of Accelerated Storage Temperature Conditions on the Shelf Life of Pasteurized Orange Juice Based on Microbiological, Physicochemical, and Color Attributes

The accelerated life testing (ASLT) method was used to evaluate the effect of increasing the storage temperature from 10 to 40 °C on the aerobic plate count (APC), the pH, and the colorimetric parameters (L*, a*, b*) of pasteurized orange juice during 40 days of storage. For APC growth, a polynomial model was found to fit better, and at the lower temperatures of 10 and 15 °C, the shelf life was longer, as expected. More specifically, 15 and 10 days were needed, respectively, until the rise in the APC population to 1000 cfu/mL. However, for the temperature range of 30–40 °C, only approximately 3 days were needed to reach 1000 cfu/mL APC. Regarding pH, according to an exponential 3P model, a stable trend was apparent at all temperatures until 30 days of storage, followed by a more abrupt decreasing trend at 25 °C. The lightness (L*), redness (a*), and yellowness (b*) of the juice showed a decreasing trend with the temperature increase, and this trend was more profound at higher temperature levels. The multiple regression analysis between the predictors L*, a*, b*, pH, storage temperature, and the APC response showed an increase in APC growth when the colorimetric parameters decreased and the temperature increased.

Bayesian reliability acceptance sampling plan with optional warranty under hybrid censoring

AbstractThis work considers the design of a Bayesian reliability acceptance sampling plan (RASP) under a hybrid censored life test for the products sold under an optional warranty. The consumer and manufacturer agree on a common lifetime distribution of the product. However, they differ in the assessment of the prior distributions because of the adversarial nature of the consumer and manufacturer. The consumer takes a decision based on his/her utility and prior belief without a warranty offer by the manufacturer. If the decision is rejection, the manufacturer provides warranty offer to the consumer. If the consumer rejects the lot with a warranty, the manufacturer conducts a life test under the hybrid censoring scheme (HCS) and provides lifetime information to the consumer. The consumer updates his/her belief based on lifetime information provided by the manufacturer. The consumer then takes a decision of acceptance or rejection of the lot based on updated beliefs. The task of the manufacturer is to determine the optimal life testing plan.

Accelerated Life Tests for Time-Dependent Response Characterization of Functionalized Piezoelectric Microcantilever-Based Gas Sensors

This article explores the accelerated lifetime test approach to characterize the time-dependent response of a piezoelectrically driven microcantilever (PD-MC) based gas sensor. The novelty here relies on demonstrating how accelerated lifetime tests can be useful to differentiate sensing mechanisms for non-linear gas sensors. The results show the determination of the sensor’s optimum operation time while maintaining result validity. The approach is demonstrated for 1,5-diaminopentane (cadaverine), a volatile organic compound (VOC) whose concentration in meat and fish products has been proven viable for determining the shelf life. A PD-MC functionalized with a cadaverine-specific binder was therefore incorporated into a hand-held electronic nose, and the response was found to be highly reliable within a specific resonance frequency shift, enabling the accurate prediction of meat and fish expiration dates. To identify the limits of detection in terms of cadaverine concentration and sensor lifetime, this study applies the results of accelerated life tests into a Weibull distribution analysis to extract the expected time to failure. For the accelerated life tests, a functionalized PD-MC was exposed to high concentrations of cadaverine, i.e., 252.3 mg/kg, 335.82 mg/kg, and 421.08 mg/kg, compared to the nominal concentration of 33 mg/kg observed in meat and fish samples. Furthermore, we demonstrate the differentiation of the response mechanisms of the system accruing from the concentration-dependent interaction of cadaverine with the binder. This enables the determination of the upper limit of the analyte concentration for a stable response. The findings suggest that the functionalized PD-MC sensor exhibits a linear and predictable response when exposed to a standard cadaverine concentration of 33 mg/kg for up to 93.01 min.

Effect of Hydrogen on High Cycle Fatigue Properties of L360 Pipeline Steel Notched Specimens.

The fatigue characteristics of notched specimens of L360 pipeline steel in hydrogen and nitrogen environments were investigated by high cycle fatigue life tests and fatigue crack growth rate tests. The fracture morphology in the nitrogen environment was dominated by microcracks and fatigue strips. The fatigue fracture had distinctly different regions in the hydrogen environment. The outer region of the fracture in the hydrogen environment was similar to the nitrogen environment, but a large number of hydrogen embrittlement features were found in the inner region. The fatigue crack growth rate tests were analyzed in conjunction with fatigue life tests. It was found that more fatigue cycles were required to achieve the stress intensity factor ΔK for rapid hydrogen-promoted crack propagation at lower stress. The region with hydrogen embrittlement features increases with decreasing stress.

Proton-Pump Inhibitors and Fat Absorption in Cystic Fibrosis and Pancreatic Insufficiency: A Randomized Crossover Pilot Trial.

Dietary fat malabsorption contributes to poor nutritional status in patients with cystic fibrosis (CF) and exocrine pancreatic insufficiency (EPI). Prescribing gastric acid-reducing agents such as proton-pump inhibitors (PPI) as an adjunct to pancreatic enzyme replacement therapy (PERT) to improve dietary fat absorption has been accepted in clinical practice despite limited evidence. This was a pilot randomized, double-blind, placebo-controlled crossover trial of subjects aged 12 and older with CF and EPI assessed on placebo and omeprazole to determine if PPI improved the efficacy of PERT as indicated by measures of dietary fat absorption. Fat malabsorption via stool coefficient of fat absorption (CFA) and malabsorption blood test (MBT), gastrointestinal pH (wireless motility capsule [WMC]), and quality of life (QOL) were assessed after 14days on both placebo or PPI (omeprazole). Total 19 subjects enrolled, 13 were randomized, and 9 provided paired results on placebo and PPI. The 3 subject results for CFA were as follows: 1 increased, 1 decreased, and 1 was within the reference range in both tests for fat absorption. For 9 MBT subjects, 7 decreased and 2 increased fat absorption. For the 4 WMC studies, no change in transit times, nor in pH profiles were noted. No differences were seen in the domains of the two QOL questionnaires comparing placebo and PPI. These limited descriptive pilot study results in participants with CF and EPI on PERT evaluated by stool, blood, and QOL tests did not suggest improvement in fat absorption attributable to PPI.

Synergistic modification of Ti/PbO2 electrodes with metal ions (Nd, Al, Bi) and STAB surfactant for electrocatalytic treatment of desulfurization wastewater

In this study, PbO2 electrodes are modified by co-doping with different metallic elements (Nd, Al, Bi) and stearyl trimethyl ammonium bromide (STAB) using the electrodeposition method. The modified electrodes, designated as Ti/PbO2-Nd-STAB, Ti/PbO2-Al-STAB, and Ti/PbO2-Bi-STAB, are then applied in the electrochemical degradation of desulfurization wastewater. The surface morphology, crystal structure, and elemental valence of the prepared electrodes are analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Their electrochemical performance and stability are assessed by linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and accelerated life testing (ALT). The results reveal that modification with metallic elements and STAB significantly enhances the physicochemical and electrocatalytic performance of the Ti/PbO2 electrode. Among the modified electrodes, the Ti/PbO2-Nd-STAB electrode exhibits the most compact and homogeneous surface morphology, the highest oxygen evolution potential (OEP, 2.33 V vs. SCE), the lowest chlorine evolution potential (CEP, 1.44 V vs. SCE), the largest electrochemically active surface area, the lowest charge transfer resistance, the highest electrochemical stability, and a prolonged accelerated life (65 h, which is 17 h longer than that of the unmodified electrode). Further, the optimal electrochemical oxidation process parameters for desulfurization wastewater are determined as follows: current density = 50 mA/cm2, temperature = 35 ℃, electrode spacing = 3.0 cm, and stirring rate = 300 rpm. After 300 min of electrolysis, the Ti/PbO2-Nd-STAB electrode achieves a Cl− removal rate of 86.9 % and a chemical oxygen demand (COD) removal rate of 71.2 %. After 10 cycles, the Cl− and COD removal rates decrease by 2.8 % and 1.8 %, respectively. Besides, Tafel curve analysis indicates that the chlorine evolution reaction follows the Volmer-Tafel mechanism, with the recombination of adsorbed Cl− ions on the surface oxidation film being the rate-determining step. Overall, the Ti/PbO2-Nd-STAB anode exhibits immense application potential in the treatment of desulfurization wastewater.

A Cross-Sectional Study Investigating the Role of Meaning and Purpose in Life Among Older Individuals (≥50-Years Old) in Recovery from Alcohol Use Disorder/Problem Drinking

ABSTRACT Meaning and purpose in life (MPL) is an important domain of the recovery capital model. Yet, this important recovery support mechanism has received scant attention, particularly in relation to older individuals recovering from alcohol use disorder (AUD)/problem drinking. Framed within Viktor Frankl’s theory of meaning, the study used two measures, the Purpose in Life Test and the Meaning in Life Questionnaire, to collect the data of 381 older individuals (≥50-years old) in recovery. The data was analyzed against four independent variables: onset age of problem drinking (early- and late-onset), gender, continuous years in recovery and recovery pathways. The study found a significant relationship between MPL and continuous years in recovery, suggesting that as the length of time in recovery increases, so too, do levels of MPL.

Study on type of magnetic suspension rotor groove and wear of drop touchdown bearing

The active magnetic bearing (AMB) is widely used in the field of flywheel energy storage system (FESS) in wind power generation. This study mainly studies the magnetic suspension rotor groove (MSRG) of FESS and the wear of drop touchdown bearing (DTB). The mathematical model of air gap magnetic field waveform on stator surface and Plath equation of control in air gap region were established. Contrastive analysis of conventional, second harmonic and third harmonic ‘petal-shaped’ MSRG in AMB. The life test of DTB on magnetic suspension rotor was carried out for 24000r/min and lasted for 1500 h. The second harmonic ‘petal-shaped’ MSRG could not only generate reluctance torque and increased the torque density of the motor, but also increased the fundamental component and excitation torque component by reducing the peak value of the magnetic field. The temperature ranges of front and rear DTB were ‘30℃–46℃’ and ‘26℃–40℃’, respectively. After service, the maximum thickness of metamorphic layer in the DTB raceway was 6 μm. After service, the content of Fe in the metamorphic layer of DTB raceway decreased by 10.11% and the content of C increased by 2.41%. Raceway hardness of DTB after service was 59.67 HV higher than that before service.

Dynamic fuzzy comprehensive evaluation of wet friction components performance degradation based on G1-CRITIC

High power density wet friction components are crucial in heavy equipment transmission systems, directly influencing equipment reliability. This paper proposes a fuzzy comprehensive evaluation method with combined weighting, which dynamically divides the performance degradation of wet friction components into three stages. It constructs a multi-indicator, multi-level evaluation system, in which the performance degradation data is obtained from the wet clutch accelerated life test. Additionally, we utilize the combined weighting method to dynamically allocate weights for evaluation indicators at different stages and introduce the trapezoidal distribution membership function. The accuracy of the fuzzy comprehensive evaluation model is then verified by using two prediction models as a comparison method. The results indicate that the model achieves an average relative error of 14.79% and a correlation coefficient R2 of 0.9580, indicating higher usability and accuracy than the prediction models. Furthermore, the evaluation indicator weights are more sensitive to pressure variations.

Effect of ultrasonic vibration on fatigue life of Inconel 718 machined by high-speed milling: Physics-enhanced machine learning approach

Ultrasonic assisted high-speed machining (UAHSM) can be served as a thermomechanical surface sever plastic deformation (SSPD), because of the high-frequency impact load exerting to the sample together with thermomechanical loads due to shearing and plowing. Despite existing of few works which studied the impact of ultrasonic vibration on fatigue life assessment of difficult-to-cut material by experimental approach, they couldn’t provide an in-depth analysis to identify the underlying mechanisms of fatigue due time-consuming and costly fatigue life tests. Hence, elucidating the role of ultrasonic vibration in UAHSM on variation of fatigue life needs further studies. In order to do so, in the present work, a hybrid predictive approach based using ANFIS-based machine learning model and micromechanical Navaro-Rios (NR) fatigue crack propagation model has been introduced to directly correlates the UAHSM’s parameters to fatigue life. Here the former correlates feed rate, cutting velocity and vibration amplitude as process inputs, to surface integrity aspects (SIA) viz residual stress, roughness and grain size as output. Then, the modeled SIA are correlated to fatigue life using the former. The introduced hybrid model was then verified through series of UAHSM by examining the fatigue lives of milled Inconel 718 using four-point bending fatigue tests. Upon confirmation of the developed model, a comprehensive study was carried out to find how the process factors impact variation of SIA and subsequently fatigue. It was found from the results of developed models and confirmatory experiments that the role of ultrasonic vibration on improved fatigue life is mainly due to inducing compressive residual stress and more refined microstructure than the roughness.

Impacts of zinc enriched spirulina as an adjunct to conventional treatment of patients with Chronic Obstructive Pulmonary Disease: Study protocol for a North African randomized controlled trial (SPIRICOPD).

Chronic Obstructive Pulmonary Disease (COPD) is a respiratory condition strongly related to oxidative stress. Recent studies have explored the potential benefits of nutritional supplementation in managing several conditions. To investigate the effects of zinc-enriched Spirulina Supplementation (ZSS) on patients with COPD. This study is a monocentric randomized controlled clinical trial. COPD-eligible adult male patients under 65 years of age, receiving regular medical treatment, will be included. They will continue their conventional medical treatment following the GOLD 2023 guidelines for COPD. Ninety subjects will be randomly assigned to either the experimental group (G1) or the control group (G2) in a 1:1 ratio. G1 will receive ZSS (1 g/day) for 2 months, while G2 will continue only basic medical treatment. The study will assess oxidant-antioxidant balance, lung function through pulmonary function tests, functional capacity via the 6-minute walking test, lipid profile, dyspnea, and health-related quality of life. All outcomes will be measured at baseline and two months later after supplementation completion. After the 8-week treatment, patients will be followed up for an additional 4 weeks. Ethics approval was obtained from the faculty of medicine of Sousse ethics committee. It is expected that ZSS can positively impact the oxidant/antioxidant balance in patients with COPD after two months of supplementation. The authors anticipate that ZSS may improve various physiological parameters, such as lung function, exercise capacity, endothelial function, and metabolic profile, leading to an overall improvement in the quality of life of patients with COPD.