Remaining Useful Life Prediction Method for Multi-Component System Considering Maintenance:Subsea Christmas Tree System as A Case Study

Maintenance is an important technical measure to maintain and restore the performance status of equipment and ensure the safety of the production process in industrial production,and is an indispensable part of prediction and health management.However,most of the existing remaining useful life(RUL)prediction methods assume that there is no maintenance or only perfect maintenance during the whole life cycle;thus,the predicted RUL value of the system is obviously lower than its actual operating value.The complex environment of the system further increases the difficulty of maintenance,and its maintenance nodes and maintenance degree are limited by the construction period and working conditions,which increases the difficulty of RUL prediction.An RUL prediction method for a multi-omponent system based on the Wiener process considering maintenance is proposed.The performance degradation model of components is established by a dynamic Bayesian network as the initial model,which solves the uncertainty of insufficient data problems.Based on the experience of experts,the degree of degradation is divided according to Poisson process simulation random failure,and different maintenance strategies are used to estimate a variety of condition maintenance factors.An example of a subsea tree system is given to verify the effectiveness of the proposed method.

Fasting and Cancer: Practice and Patients’ Quality of Life during Ramadan

Introduction: Ramadan is the ninth lunar month of the Muslim calendar, and fasting during Ramadan is one of the five pillars of Islam. Muslim cancer patients and health professionals are faced with a dilemma between the necessity of fasting and its possible adverse effects during Ramadan on the health status of cancer patients. We believe that addressing the issue of fasting in cancer patients is of global interest. Objectives: Prevalence of fasting in cancer patients during Ramadan;Predictive factors of Ramadan fasting in cancer patients;The effect of fasting during Ramadan on the quality of life of cancer patients. Materials and Methods: A structured questionnaire was used to interview adult cancer patients who received chemotherapy IV—or oral treatment at the medical oncology department at the Hassan II University Hospital in Fez during the month of Ramadan 1443 Hijri (April to May 2022). The quality of cancer patients’ lives during their fasting practice in Ramadan was evaluated via the QLQ-C30 questionnaires. Results: 48% of patients did not fast during Ramadan, 22% and 30% were partial and complete fasters respectively. Patients, with OMS 0 to 1, who receive outpatient treatment, non-metastatic patients and patients on oral treatment were more frequent in the completely fasted group. All these factors showed statistically significant values (p < 0.05). 44% of patients sought advice from the treating oncologist if they could fast, while only 15% of patients during Ramadan asked an imam if they could be excused from fasting. A comparison of the QLQ-C30 data showed a significant improvement in emotional functioning with fasting, however, patients had clinically more but not significantly fatigue after fasting. Conclusion: Female gender, good WHO, non-metastatic disease, and oral or outpatient treatment were more likely to be fasting. This study argues that fasting did not influence the quality of life, and appears to significantly improve emotional functioning in cancer patients during Ramadan.

Investigation into the Methodology and Implementation of Life Cycle Engineering under China’s Carbon Reduction Target in the Process Industry

The industrial sector is the primary source of carbon emissions in China.In pursuit of meeting its carbon reduction targets,China aims to promote resource consumption sustainability,reduce energy consumption,and achieve carbon neutrality within its processing industries.An effective strategy to promote energy savings and carbon reduction throughout the life cycle of materials is by applying life cycle engineering technology.This strategy aims to attain an optimal solution for material performance,resource consumption,and environmental impact.In this study,five types of technologies were considered:raw material replacement,process reengineering,fuel replacement,energy recycling and reutilization,and material recycling and reutilization.The meaning,methodology,and development status of life cycle engineering technology abroad and domestically are discussed in detail.A multidimensional analysis of ecological design was conducted from the perspectives of resource and energy consumption,carbon emissions,product performance,and recycling of secondary resources in a manufacturing process.This coupled with an integrated method to analyze carbon emissions in the entire life cycle of a material process industry was applied to the nonferrous industry,as an example.The results provide effective ideas and solutions for achieving low or zero carbon emission production in the Chinese industry as recycled aluminum and primary aluminum based on advanced technologies had reduced resource consumption and emissions as compared to primary aluminum production.

Optimizing Multi-Row Cam Roller Bearing for Long Fatigue Life of Hydraulic Motors

Cam-lobe radial-piston hydraulic motors are widely used as rotation driving units for various marine machinery owing to their ultrahigh output torque(more than 100 kN m).A multi-row cam roller bearing(MCRB)is the key component that directly determines the fatigue life of a cam-lobe radial-piston hydraulic motor.However,compact geometry and complex loads render MCRB susceptible to fatigue failure,highlighting the need for an optimized MCRB to achieve longer fatigue life and higher reliability.Therefore,this study proposes an innovative geometry optimization method for an MCRB to improve its fatigue life.In this method,a quasi-static model was developed to calculate the load distribution,with the fatigue life of the MCRB calculated using both basic dynamic loading and load distribution.Subsequently,a genetic algorithm was used to obtain the optimized geometry parameters,which significantly improved the fatigue life of the MCRB.Finally,a loading test was conducted on a hydraulic motor installed with both the initial and optimized MCRB to validate the effectiveness of the proposed optimization method.This study provides a theoretical guideline for optimizing the design of MCRB,thereby increasing the fatigue life of hydraulic motors.

A method for establishing a bearing residual life prediction model for process enhancement equipment based on rotor imbalance response analysis

A rotating packed bed is a typical chemical process enhancement equipment that can strengthen micromixing and mass transfer.During the operation of the rotating packed bed,the nonreactants and products irregularly adhere to the wire mesh packing in the rotor,thus resulting in an imbalance in the vibration of the rotor,which may cause serious damage to the bearing and material leakage.This study proposes a model prediction for estimating the bearing residual life of a rotating packed bed based on rotor imbalance response analysis.This method is used to determine the influence of the mass on the imbalance in the vibration of the rotor on bearing damage.The major influence on rotor vibration was found to be exerted by the imbalanced mass and its distribution radius,as revealed by the results of orthogonal experiments.Through implementing finite element analysis,the imbalance response curve for the rotating packed bed rotor was obtained,and a correlation among rotor imbalance mass,distribution radius of imbalance mass,and bearing residue life was established via data fitting.The predicted value of the bearing life can be used as the reference basis for an early safety warning of a rotating packed bed to effectively avoid accidents.

A Hybrid Approach for Predicting the Remaining Useful Life of Bearings Based on the RReliefF Algorithm and Extreme Learning Machine

Accurately predicting the remaining useful life(RUL)of bearings in mining rotating equipment is vital for mining enterprises.This research aims to distinguish the features associated with the RUL of bearings and propose a prediction model based on these selected features.This study proposes a hybrid predictive model to assess the RUL of rolling element bearings.The proposed model begins with the pre-processing of bearing vibration signals to reconstruct sixty time-domain features.The hybrid model selects relevant features from the sixty time-domain features of the vibration signal by adopting the RReliefF feature selection algorithm.Subsequently,the extreme learning machine(ELM)approach is applied to develop a predictive model of RUL based on the optimal features.The model is trained by optimizing its parameters via the grid search approach.The training datasets are adjusted to make them most suitable for the regression model using the cross-validation method.The proposed hybrid model is analyzed and validated using the vibration data taken from the public XJTU-SY rolling element-bearing database.The comparison is constructed with other traditional models.The experimental test results demonstrated that the proposed approach can predict the RUL of bearings with a reliable degree of accuracy.

Exploring the frontiers of life research

Introduction Life research serves as the vanguard of scientific exploration,where the intricate symphony of living organisms unfolds,unraveling the mysteries of existence.Encompassing biology,genetics,ecology,and beyond,it weaves a narrative delving into life’s essence,propelling us toward a profound comprehension of our world.In the relentless pursuit of knowledge,life researchers decode fundamental processes,from unraveling DNA’s secrets to probing the delicate balances of ecosystems.The hallmark of contemporary life research lies in its interdisciplinary character,fostering collaboration among biologists,chemists,physicists,and computational scientists.This collaborative synergy embraces a holistic approach,enabling researchers to address intricate biological questions,spur innovation,and redefine the limits of what was once deemed possible.

Evaluation of the Quality of Life of Patients Suffering from Chronic Rhinosinusitis in a Hospital Setting in Kinshasa

Background and objective: Chronic rhinosinusitis (CRS), a common disease worldwide, has a major impact on patients’ quality of life (QoL). In recent years, the measurement of health-related QoL has made it possible to assess the patient’s state of health, the severity of the CRS and the treatment. The aim of this study was to assess the QoL of patients with CRS in a hospital setting in Kinshasa. Methods: This was a cross-sectional analytical study conducted from June 2020 to May 2021 in the ENT service of the Kinshasa University Hospital and the Monkole Hospital Center. The study involved 113 patients aged at least 18 years, whose QOL was compared with that of a control group consisting of 100 non-patients. QOL was assessed using the Sino-Nasal Outcome Test (SNOT-22) Questionnaire. Results: The mean age of the patients was 41.0 years (18 - 74 years) and that of the controls was 39.1 years (19 - 77 years). More than half of the participants were university graduates. The median SNOT-22 score was 44 (14 - 78) in patients and 7 (1 - 40) in controls. Compared with subjects without CRS, patients with CRS had significantly higher scores in all four domains of the SNOT-22. Around 9 out of 10 patients had a severely impaired QoL compared with 2 out of 10 controls. Considering mildly impaired QoL, we found that in the otological and sleep domains, scores were not significantly different between patients and controls. In the case of severely impaired QoL, however, only the otological domain showed a non-significant difference in scores between the two groups. Conclusion: CRS is a real public health problem in our environment and significantly alters the QoL of patients suffering from it, with repercussions on their professional productivity;hence the need for better management.

ON POTENT ELEMENTS AND PSEUDO CLEAN RINGS

In this paper,potent index of an element and pseudo clean rings are considered.Some properties and examples of pseudo clean rings are given.We also show that Zm is pseudo clean for every 2≤m∈Z and pseudo clean rings are clean.Furthermore,we prove pseudo clean rings are directly finite and have stable range one.

Exploring the Impact of Narrative Nursing on Anxiety, Depression, and Quality of Life in Middle-aged and Young Dialysis Patients

Objective:To explore the impact of narrative nursing on anxiety,depression,and quality of life in middle-aged and young dialysis patients.Method:Eighty-six middle-aged and young dialysis patients admitted from January 2023 to December 2023 were selected and divided into a control group and a study group,with 43 patients in each group.The control group received general nursing interventions,while the study group received narrative nursing in addition to the general interventions.The levels of anxiety and depression before and after the intervention were compared,and the quality-of-life scores of the two groups were analyzed.Results:After comprehensive intervention,the scores of both groups significantly decreased(P<0.05).After intervention,the scores of the study group were more significant compared to the control group(P<0.05).Compared with the control group,the quality-of-life score of the study group showed a significant upward trend,and this difference was statistically significant(P<0.05).Conclusion:Comprehensive narrative nursing can effectively reduce anxiety in middle-aged and young dialysis patients,further enhance their quality of life,and is worth promoting in clinical practice.

Mapping the landscape of gastric signet ring cell carcinoma:Overcoming hurdles and charting new paths for advancement

BACKGROUND In recent years,the global prevalence of gastric cancer(GC)has witnessed a progressive decrease,accompanied by a step-growth in the incidence of gastric signet ring cell carcinoma(GSRCC).As precision medicine concepts progress,GSRCC,a distinct sub-type of GC,has drawn considerable attention from researchers.However,there still persist some controversies regarding the associated research findings.AIM To summarize the current obstacles and potential future directions for research on GSRCC.METHODS To begin with,all literature related to GSRCC published from January 1,2004 to December 31,2023 was subjected to bibliometric analysis in this article.Additionally,this paper analyzed the research data using CiteSpace,GraphPad Prism v8.0.2,and VOSviewer,which was obtained from the Web of Science Core Collection database.The analysis results were visually represented.RESULTS This study provided a comprehensive overview of the statistical characteristics of the 995 English articles related to GSRCC,including cited references,authors,journals,countries,institutions,and keywords.The popular keywords and clusters contain"prognosis","survival","expression","histology",and"chemotherapy".CONCLUSION The prognosis,precise definition and classification,as well as chemoresistance of GSRCC,continue to be crucial areas of ongoing research,whose directions are closely tied to advancements in molecular biology research on GSRCC.

Reevaluating health metrics:Unraveling the limitations of disabilityadjusted life years as an indicator in disease burden assessment

In 1993,the World Bank released a global report on the efficacy of health promotion,introducing the disability-adjusted life years(DALY)as a novel indicator.The DALY,a composite metric incorporating temporal and qualitative data,is grounded in preferences regarding disability status.This review delineates the algorithm used to calculate the value of the proposed DALY synthetic indicator and elucidates key methodological challenges associated with its application.In contrast to the quality-adjusted life years approach,derived from multi-attribute utility theory,the DALY stands as an independent synthetic indicator that adopts the assumptions of the Time Trade Off utility technique to define Disability Weights.Claiming to rely on no mathematical or economic theory,DALY users appear to have exempted themselves from verifying whether this indicator meets the classical properties required of all indicators,notably content validity,reliability,specificity,and sensitivity.The DALY concept emerged primarily to facilitate comparisons of the health impacts of various diseases globally within the framework of the Global Burden of Disease initiative,leading to numerous publications in international literature.Despite widespread adoption,the DALY synthetic indicator has prompted significant methodological concerns since its inception,manifesting in inconsistent and non-reproducible results.Given the substantial diffusion of the DALY indicator and its critical role in health impact assessments,a reassessment is warranted.This reconsideration is imperative for enhancing the robustness and reliability of public health decisionmaking processes.

Experimental study of water aging on asphalt during service life of pavements

In order to further simulate the real condition of pavements during the service life,moisture is considered in long-term aging tests based on the existing researches about thermal aging and oxidation aging of asphalt.Water is injected into the pressure aging vessel（PAV）to simulate the aging process during the service life.The performance-based strategic highway research program（SHRP）parameters G/sinδ and S（t）are adopted to evaluate the high-temperature properties and low-temperature properties of the aged asphalt,respectively.The Thailand 90# asphalt,the modified Thailand 90# asphalt and the Shell 70# asphalt are used in the test.It is found that the moisture has a significant influence on parameter G/sinδ when combined with heat and oxygen,so water aging makes high-temperature performance decay more seriously.But the low-temperature performance does not change remarkably after water aging.Since the influences of temperature,oxygen and water are taken into account in the PAV test,the accuracy of asphalt aging tests can be improved and the long-term aging process of asphalt pavement can be exactly simulated.

Optimum Constant-stress Plan for Accelerated Life Test with Censoring Ⅱ

In this paper, we obtain the optimum plan by discussing a constant-stress accelerated life test (ALT) satisfying the condition (3.3) at k stresses under an exponential distribution.

A fatigue life prediction method of rolling bearing under elliptical contact elastohydrodynamic lubrication

In order to more accurately predict the contact fatigue life of rolling bearing, a prediction method of fatigue life of rolling bearing is proposed based on elastohydrodynamic lubrication （EHL）, the 3-paameter Weibull distribution ad fatigue strength. First,the contact stress considering elliptical EHL is obtained by mapping film pressure onto the Hertz zone. Then,the basic strength model of rolling bearing based on the 3-parameter Weibull distribution is deduced by the series connection reliability theory. Considering the effect of the type of stress, variation of shape and fuctuation of load, the mathematical models of the 尸 -tS-TV curve of the minimum life and the characteristic life for rolling bearing are established, respectively, and thus the prediction model of fatigue life of rolling bearing based on the 3-paameter Weibull distribution and fatigue strength is further deduced. Finally, the contact fatigue life obtained by the proposed method ad the latest international standard （IS0281： 2007） about the fatigue life prediction of rolling bearing are compared with those obtained by the statistical method. Results show that the proposed prediction method is effective and its relative error is smaier than that of the latest international standard （IS0281： 2007） with reliability R 〉 0. 93.

Life Cycle Assessment of Green Buildings Based on Grey Clustering Method

To promote and develop green buildings,a standardized,applicable and easily operable index system for the assessment of such buildings was established on the basis of life cycle cost effectiveness.From the perspectives of environment-friendly materials,water resource environment,energy and environment,quality of indoor and outdoor environment,operation and management,and economical efficiency of life cycle,a modified index system was built,AHP was applied to obtain weights of indexes,evaluation methods of the grey system were used to evaluate green buildings,case study was adopted to verify the practicability and scientificity of the method.The results showed that Grey Clustering Method was an objective and reliable tool to evaluate green buildings,the calculation was simple,practical and easily operable,and moreover,the assessment process could be optimized by computer programming to improve its efficiency and precision.

深水采油树Spring-Seal密封圈接触模型构建与实验测试

为提高深水采油树在高压、高温、低温等工况下长时间工作的稳定性,对采油树密封圈进行重新设计,提出Spring-Seal密封圈(以下简称S密封圈);基于赫兹接触理论、填料密封接触理论,重新构建S密封圈接触力学模型;建立有限元仿真分析模型,分析不同条件下S密封圈的密封性能,同时验证新建接触模型的合理性;利用实验测试S密封圈的实际密封效果。研究结果表明:S密封圈在高压、高温、低温等工况下能够长时间稳定工作且密封性能良好。研究结果可为S密封圈的接触研究及工程运用提供理论参考。

Raising medium function of environmental engineering by using life rubbish to produce carpet turf

Abundant material with low cost was utilized to raise medium function of producing carpet turf by life rubbish. The results showed that the material used could strikingly raise water retentiveness and ventilating of medium. Through the determination of the effect of each growth index of several turfgrass, emergence density, plant height, root growth and individual plant′s net primary production were all positively related to the material′s amount mixed, showing that the mixture of material could promote turfgrass growth, further proving that the material used raised medium function of producing carpet turf by life rubbish and made most use of life rubbish resources. It provided a scientific base is for application of environmental engineering by using life rubbish to produce carpet turf. So the study had both important theoretic meaning and applied value.

Reliability estimation and remaining useful lifetime prediction for bearing based on proportional hazard model

As the central component of rotating machine,the performance reliability assessment and remaining useful lifetime prediction of bearing are of crucial importance in condition-based maintenance to reduce the maintenance cost and improve the reliability.A prognostic algorithm to assess the reliability and forecast the remaining useful lifetime(RUL) of bearings was proposed,consisting of three phases.Online vibration and temperature signals of bearings in normal state were measured during the manufacturing process and the most useful time-dependent features of vibration signals were extracted based on correlation analysis(feature selection step).Time series analysis based on neural network,as an identification model,was used to predict the features of bearing vibration signals at any horizons(feature prediction step).Furthermore,according to the features,degradation factor was defined.The proportional hazard model was generated to estimate the survival function and forecast the RUL of the bearing(RUL prediction step).The positive results show that the plausibility and effectiveness of the proposed approach can facilitate bearing reliability estimation and RUL prediction.

High Pressure Treatment Changes Spoilage Characteristics and Shelf Life of Pacific Oysters(Crassostrea gigas)During Refrigerated Storage

The effects of high pressure(HP) treatment on spoilage characteristic and shelf life extension of Pacific oysters(Crassostrea gigas) during refrigerated storage were studied.Results showed that HP treatment of 275 MPa for 3 min or 300 MPa for 2 min could achieve 100% full release of oyster adductor muscle,pressures higher than 350 MPa caused excessive release as the shells of oysters were broken,thus use of higher pressures should be cautious in oyster processing industry because of its adverse impact on the appearance of shells.HP treatment(300 MPa,2 min) was proper for the shucking of Pacific oyster(Crassostrea gigas) in China.This treatment caused no organoleptic disadvantage.Moreover,HP treatment resulted in obvious differences in biochemical spoilage indicators(p H,TVB-N and TBARS) changes and volatile compounds profile determined by electronic nose during storage.HP treatment(300 MPa,2 min) also led to a reduction of aerobic bacterial count(APC) by 1.27 log cycles.Furthermore,the APC values of oysters treated by HP were always lower than those of the control samples during storage.Based on the organoleptic,biochemical and microbiological indicators,shelf life of 6-8 d for control and 12 d for HP-treated oysters could be expected.HP treatment showed great potential in oyster processing and preservation.