Maintenance In Order Research Articles

Prognosis of Water Quality Sensors Using Advanced Data Analytics: Application to the Barcelona Drinking Water Network.

Water Utilities (WU) are responsible for supplying water for residential, commercial and industrial use guaranteeing the sanitary and quality standards established by different regulations. To assure the satisfaction of such standards a set of quality sensors that monitor continuously the Water Distribution System (WDS) are used. Unfortunately, those sensors require continuous maintenance in order to guarantee their right and reliable operation. In order to program the maintenance of those sensors taking into account the health state of the sensor, a prognosis system should be deployed. Moreover, before proceeding with the prognosis of the sensors, the data provided with those sensors should be validated using data from other sensors and models. This paper provides an advanced data analytics framework that will allow us to diagnose water quality sensor faults and to detect water quality events. Moreover, a data-driven prognosis module will be able to assess the sensitivity degradation of the chlorine sensors estimating the remaining useful life (RUL), taking into account uncertainty quantification, that allows us to program the maintenance actions based on the state of health of sensors instead on a regular basis. The fault and event detection module is based on a methodology that combines time and spatial models obtained from historical data that are integrated with a discrete-event system and are able to distinguish between a quality event or a sensor fault. The prognosis module analyses the quality sensor time series forecasting the degradation and therefore providing a predictive maintenance plan avoiding unsafe situations in the WDS.

Modelling and solving the multi-quays berth allocation and crane assignment problem with availability constraints

In this work, we are interested in the multi-quays berth allocation and crane assignment problem under availability restrictions. Availability restrictions may arise due weather conditions, or when, for example, cranes must undergo planned maintenance in order to stay in good performance. This problem was inspired by a real-case of a bulk port in Morocco. To solve the problem we propose at first a mixed-integer programming model. Then, in view of the limitations of the proposed model, we investigate a set of heuristics based on general variable neighborhood search with three variants of variable neighborhood descent as a local search. To validate the proposed model and the proposed heuristic approach, real-world instances are used. The computational results reveal that CPLEX MIP solver consumes a lot of CPU time to solve this model, even sometimes failing to guarantee the optimality of the provided solution. On the other hand, the proposed GVNS heuristic turns out to be very efficient in solving the considered problem.

Classification of Faults in Multicore Cable via Time–Frequency Domain Reflectometry

Owing to the increasing complexity of electrical systems, diagnostic techniques of cables used for connecting electrical elements are essential for system maintenance in order to prevent a failure that can cause significant impacts on the overall electrical systems. Multicore structures are typically used as control and instrumentation cables in nuclear power plants, and the failure of the control and instrumentation cables can result in a disaster such as a radiation leak. In this paper, a method for the diagnosis of multicore cables is proposed based on the reflectometry. The diagnosis relates to the classification of defective cores in joint, which is one of the weakest parts in cable systems. The reflected signals obtained through reflectometry are converted into images by an advanced image processing algorithm, and the images are classified using artificial neural networks. The proposed method is demonstrated by experimental data using a real-world multicore cable. In the experiment, the faults are emulated similar to real-world defects using a potentiometer. It is expected that the proposed technique will enhance the stability and reliability of multicore cable systems.

Analytical determination of the availability of a rotary excavator as a part of coal mining system: Case study: Rotary excavator SchRs 800.15/1.5 of the Drmno open pit

Rotary excavators as the basic machines at the open pits of lignite operate in very difficult working conditions, where they are constantly expected to be highly productive, reliable, available and safe as the production carriers. Determining the availability as well as the duration and number of failures using the analytical methods allows to analyze the key influencing factors on their occurrence and values of these parameters and to determine the essential elements of system maintenance and management in order to optimize them.

Evaluation of maintenance system in emergency installation of Meuraxa Hospital Banda Aceh, Indonesia

Hospital building and all its equipment require regular maintenance in order to avoid heavier damage. The implementation of continuity of optimal hospital building maintenance is expected to reduce the incidence of heavier damage and minimize the cost of existing repair and ensure the readiness of supporting facilities for the implementation of health services to the public in the hospital. The purpose of this research is to know the maintenance system that has been applied and to identify the condition of building emergency installation in Meuraxa Hospital. This research was conducted by distributing questionnaires to 91 respondents who are employees, nurses, doctors, and families of patients who are in the installation of Meuraxa hospital in Banda Aceh. Based on descriptive analysis, obtained the highest mean value is at component of roof maintenance at Building emergency installation (X1) for 3,934. This shows that respondents assess the roof maintenance variable is good. And the lowest mean is on ceramic maintenance component (X2) for 2,894. This indicates that respondents assess ceramic maintenance are less well. The observation results show the same thing with the opinion of the respondents which is the roof conditions on emergency installation Meuraxa is categorized as mild damage and still functioning well but the color of the roof cover has faded. Similarly, in the paint maintenance (X3), window and door frames maintenance (X4), ceiling maintenance (X5), water installation maintenance (X6), electrical installation maintenance (X7), air conditioning installation maintenance (X8), sanitary maintenance (X9) ) is categorized as mild damage but still function well. On the results of these observations by researchers in general about the building emergency installation, it can be concluded that the implementation of building emergency installation maintenance has been done well.

The aspect role of building maintenance on architectural design works (case study: a College Building in West Jakarta)

Architecture design needs to be completed with design criteria and standard knowledge of building maintenance in order to estimate a design quality related to shape and building materials selection. Similarly, a design criterion needs knowledge of building operations, including its maintenance aspects. Building maintenance needs to be done, in order to building lifetime can be extended by making periodic repairs, because utilization of each building component is not the same. Generally after building implementation, began to emerge problems with degradation in quality function of each component, utility and utilization of maintenance costs that were not proportional to the building lifetime. This research was conducted at one of the college buildings in Jakarta. This study aims to observe changes in building structures conditions, determine failure location, both in terms of architecture and maintenance; and an improvements inquiry that have been made to construction components. The method used based on BRE Digest 268. Based on an investigation obtained category value reliability and condition of college building is 86.9 with good treatment condition.

Heuristics for the single machine weighted sum of completion times scheduling problem with periodic maintenance

This paper tackles the single machine scheduling problem with periodic preventive maintenance in order to minimize the weighted sum of completion times. This criterion is certainly less studied than the makespan but it remains nonetheless interesting on the theoretical and practical levels. Indeed, the weights can quantify the holding cost per unit of time of the products to transform. Thus, this criterion can represent the global holding cost. This problem is proved to be NP-hard and a mixed integer linear programming formulation is proposed to solve small size instances of the problem. To solve large instances, we proposed three properties for this problem which generalize already existing works. These properties have been of great use in designing efficient heuristics capable of solving instances with up to 1000 jobs. To evaluate the performances of the proposed heuristics, lower bounds based on special cases of the problem are provided. Computational experiments show that the average percentage error of the best heuristic is less than 10%.

Acquiring and Maintaining Technical Skills Using Simulation: Initial, Maintenance, Booster, and Refresher Training.

Simulation-based education has been shown to be an effective tool to mitigate skill decay. However, many of the strategies reported in the literature have overlapping terminology with little consensus on the timing of the strategy to prevent skill decay. In this review, we propose and provide a standardized nomenclature and framework for simulation strategies used to obtain, maintain, or regain skills that are decaying. This framework delineates four types of training: initial, maintenance, booster, and refresher. The framework differentiates these training types based on the learner competency at the time of the training, as well as the frequency and intensity of the training. Initial training is aimed at “novice” learners with the goal to achieve competency. Once competency is achieved, maintenance training prevents skill deterioration through low-dose high-frequency (LDHF) training. Booster training is used when the learner is still proficient, but competency begins to wane. Booster training occurs less frequently than maintenance training but with greater intensity to overcome the skill decay that occurs over time. Refresher training is aimed at re-establishing skill levels after competency has reached unsatisfactory levels. Refresher training is higher intensity than booster and maintenance training. We describe simulation-based strategies reported in the literature that can be used for each type of training. We conclude that there should be an increased emphasis in medical education towards maintenance and booster training in order to preserve skills before competency is lost.

Comparing Data Sources for Condition Monitoring Suitability

In our global competitive markets, industrial companies are forced to strive for the best achievable economic efficiency. This is valid for the whole product life cycle. For machine manufacturers, this often means exploring new and better ways of product maintenance, e.g. moving from scheduled or reactive maintenance towards condition-based maintenance in order to reduce the total cost of ownership. In machines with gearboxes, vibration picked up at the machine housing often serves as input signal for performing condition monitoring. However, other measurable variables such as the loaded transmission error exist, too. Even for one physical dimension such as acceleration, many different types of sensors with different properties are available. This work provides an insight on the suitability of different kinds of measurements and sensors for gear damage detection. It takes into account the specific properties of various kinds of gear damage as well as the operating point of the gearbox to be monitored. Based on the physical properties of real sensors, adequate sensor equipment for condition monitoring is selected.

Line maintenance within transmission expansion planning: a multistage framework

Maintenance in transmission networks is an economical way to reduce upgrading network costs without decreasing its reliability. Hence, new studies regarding transmission expansion planning (TEP) must take into account the effects of maintenance in order to obtain realistic and economic expansion investment plans. This work presents a novel framework for multistage TEP, considering line maintenance, i.e. the expansion cost of the transmission system, network losses, costs of old-line replacement and maintenance, cost of newly constructed line maintenance, and cost of replaced line maintenance, are simultaneously optimised. The advantage of this approach is the fact that the lifetimes of the lines that are replaced, retained, and added to the transmission system are changing during the expansion horizon. These lifetimes have an impact on the maintenance expenses. Annual maintenance costs are also affected by the inflation rate. Hence, both the lifetime and inflation rate roles are integrated into the proposed model. The robustness and effectiveness of the model are tested on the IEEE 24-bus test system, using a particle swarm optimisation algorithm. The results show that the proposed formulation finds more economic investment plans for TEP when compared with those found using static formulations considering the maintenance available in specialised literature.

A service-life cycle approach to maintenance and energy retrofit planning for building portfolios

Residential buildings account for almost a quarter of the total energy use in Sweden and building owners are, therefore, under pressure from policy makers to improve the energy performance of their buildings. Building portfolio owners (BPOs) generally face multiple barriers in energy efficiency investments such as financial constraints and lack of knowledge of the current state when planning energy efficiency measures.This paper presents a method for cost-optimal scheduling of maintenance and retrofit measures on a portfolio level by drawing on research on building stock modeling and maintenance retrofit planning. The method uses a building stock modeling approach to model costs, energy and greenhouse gas emissions (GHG)of a building portfolio and combines this with a method for optimal maintenance and retrofit scheduling in order to forecast and optimize the timing of measures on a building portfolio level. This enables the integrated long-term planning on retrofit investments and reduction of energy demand and GHG emissions for a portfolio of existing buildings.The application to the building portfolio of the municipal housing company of Gothenburg showed that by optimizing the maintenance and retrofit plans, ambitious retrofit measures can be introduced in the majority of the buildings with a positive effect on the service-life cycle costs. Moreover, the method is easily transferable to other building portfolios in Sweden as it builds up on nationally available data sets but is ideally complemented and verified using inspection data and existing maintenance plans of the BPOs in future applications.

Electric pole failure: A safety concern

A galvanized electric street lamp pole with expected life of 25 years, near a slag dumping area failed from its base after 5 years of service. The base was found to be severely corroded and pole completely covered by mud. Visual inspection revealed no pitting at the inner surface but thinning at the base. 200 μm zinc coating was absent at the fractured region but remained intact at the inner surface. Finite Element Analysis showed that the corroded pole with 1.5 mm thickness (measured in failed zone) would start failing due to high stress exceeding yield strength at a wind speed of 86 km/h, much lower than that prevalent confirming that the pole failed due to corrosion. The soil pH was 8.0–9.0 at which the zinc coating was stable. Resistivity and moisture content of the soil were measured to be 333 Ω and 56% respectively. In order to investigate soil corrosivity for buried structural materials the oxidation reduction potential was measured. At this combination of resistivity, moisture content and ORP the soil was highly corrosive. The decreased resistivity, possibly due to the presence of ions from condensed CO gas hanging and dripping just above the failed pole, enhanced flow of ions thereby making the soil electrolytic resulting in faster formation of Zn2+ ions. The pole thus failed from the base due to accumulation of mud creating an oxygen concentration cell at the interface. Tar based cathodic coating was recommended to combat oxygen concentration cell corrosion along with proper maintenance and mud removal in order to avoid such kind of failure.

Internet of Things enabling condition-based maintenance in elevators service

PurposeThe purpose of this paper is to demonstrate how Internet of Things (IoT) technology can enable highly distributed elevator equipment servicing by using remote-monitoring technology to facilitate a shift from traditional corrective maintenance (CM) and time-based maintenance (TBM) to more predictive, condition-based maintenance (CBM) in order to achieve various benefits.Design/methodology/approachLiterature review indicates that CBM has advantages over conventional CM and TBM from a theoretical perspective, but it depends on continuous monitoring enhancement via advanced IoT technology. An in-depth case study was carried out to provide practical evidence that IoT enables elevator firms to achieve CBM.FindingsFrom a theoretical perspective, the CBM of elevators makes business sense. The challenges lie in data collection, data analysis and decision making in real-world business contexts. The main findings of this study suggest that CBM can be commercialized via IoT in the case of elevators and would improve the safety and reliability of equipment. It would, thus, make sense from technological, process and economic perspectives.Practical implicationsOur longitudinal real-world case study demonstrates a practical way of making the CBM of elevators widespread. Integrating IoT and other advanced technology would improve the safety and reliability of elevator equipment, prolong its useful life, minimize inconvenience and business interruptions due to equipment downtime and reduce or eliminate major repairs, thus greatly reducing maintenance costs.Originality/valueThe main contribution of this paper lies in the empirical demonstration of the benefits and challenges of CBM via IoT relative to conventional CM and TBM in the case of elevators. The authors believe that this study is timely and will be valuable to firms working on similar research or commercialization strategies.

Peningkatan Pengetahuan Ketahanan Ekonomi Melalui Keterampilan Otomotif Pada Siswa Ibnu Sina

Family resilience is crucial to achieving regional or regional resilience, then regional resilience will ultimately determine the achievement of national security. One part of family resilience is family economic resilience. To increase Family Economic Resilience can be by improving skills. Skills in the automotive field are one of the skills that have the potential to improve living standards. We can see this argument from the growth of motorized vehicles that are increasing from year to year which requires routine maintenance in order to operate optimally. This is an opportunity for people who are experts in the field of care. Aliyah Madrasah Ibnu Sina seeks to improve the skills of students in the automotive field, so that students can be independent and can improve the economic resilience of their families. The skills in the automotive field are also trying to be raised as the theme of community service activities involving Ibn Sina Madrasah Aliyah students. This activity is using training methods, lectures and brochures. As a result of this activity, students gain knowledge and insights that automotive skills can improve economic resilience.

Study of Isolated Bacteria from Burn Wound of Patients Attended Plastic Surgery and Burns Unit

Burns are one of the most public forms of trauma. Patients with severe thermal damage need instant focused maintenance in order to reduce morbidity and mortality. The aim of this study was to determine the prevalence of bacteria causing burin infection and their antibiotic resistance in Kirkuk city. This study carried out at the Plastic Surgery and Burns Unit in Azadi teaching hospital, Kirkuk-Iraq from January 2017- March, 2019. The study included 80 burned patient (50 females and 30 males), with age range 10-60 years. Swabs were taken from areas that seemed deep, with discharge, and the swabs were directly transported to the Microbiology Unit of the hospital. Data on age, gender and type of burn were also collected from the patients’ clinical folder. The wound swabs were instantly cultured, then the isolated bacteria were subcultured for antibiotic sensitivity. The study showed that 82.5% (66 of 80) of patients enrolled in the study had positive culture of wound swab and 17.5% was negative. The highest rate of isolated bacteria from burn infection (38.75%) were from patients within the age group 29-29 year, followed by 23.75% in patient within the age group 1019 year while the lowest rate (7.5%) was within the age group 50-60 year. The study presented that 62.5% (50 of 80) of patients enrolled were females and 37.5% (30 of 50) were males. In this study, bacterial culture was positive in 66 of 80 cases, with the predominant bacteria being Staphylococcus aureus (33.33%) (Table 3), followed by Pseudomonas aeruginosa (31.81%), E. coli (15.15 %), Klebsiella sp. (13.64%), Proteus sp. (3.03%) and (1.52%) for each of Acinetobacter sp. and Enterobacter sp. The study showed that most of S. aureus isolates were resistant to ampicillin, trimethoprim, ciprofloxacin, gentamicin and cefotaxime, most of Pseudomonas aeruginosa isolates were resistant to ampicillin, trimethoprim, ciprofloxacin and Augmentin, most of E. coli isolates were resistant to ampicillin, trimethoprim, Augmentin, trimethoprim, ciprofloxacin, ceftriaxone and tetracycline

Integrated Maintenance-Quality strategies taking into account the impact of the system degradation on the quality of output products

This paper deals with integrated models joining maintenance and quality. We consider a manufacturing system composed of a single machine subject to an increased random failure rate and producing conforming and non-conforming items. In order to decrease the random failure rate and its impact on the quality of output products, a bloc type preventive maintenance strategy with minimal repair is considered. Our study consists in developing integrated analytical models joining maintenance and quality in order to determine the optimal preventive maintenance plan taking into account the progressive quality perturbation and the economic impact of reworking activities. Two strategies are developed. In fact, for the first strategy, we propose reworking activities for all non-conforming products in order to improve their quality condition and to sell all batches at the best price Pmax. The aim of this strategy is to found the optimal number of batches produced and reworked N* before each preventive maintenance action, maximizing the total net profit per time unit PT1. For the second strategy, the same problem is studied but for a finite horizon. Two mathematical models are developed in order to find the optimal value of the decision variable N* for both strategies. Numerical examples are presented in order to illustrate proposed models and a sensitivity study is developed to evaluate the influence of the variation of some parameters.

ВПЛИВ ОРГАНІЗАЦІЇ ТЕХНІЧНОГО ОБСЛУГОВУВАННЯ НА ЕФЕКТИВНІСТЬ ЕКСПЛУАТАЦІЇ ТЯГОВОГО РУХОМОГО СКЛАДУ

During the existence of railways, schedule preventive maintenance system of different levels has been established (M-i, where i – maintenance number, current repair (CR-j, where j – repair number and overhaul (O-m, where m – overhaul number). Frequency and amount of maintenance, CR are regulated by manufacturers and in the process of operation are partially adjusted according to the data from equipment failures. At the same time, the time between failures under different failure distribution laws has a large variance, which can lead to spreading of the timing of M, CR for a specific traction rolling stock (TRS). Under these conditions, against the background of the general deterioration of the technical state of TRS equipment, it is advisable to change to a mixed maintenance system, CR, which provides the organization of continuous monitoring of changes in the status of TRS equipment and the implementation of a TRC equipment maintenance system according to this condition. This article deals with the issues of the impact of maintenance organization under various laws of failures development on the traction rolling stock operation efficiency. Based on the choice of reliability parameters for various failure distribution laws of equipment, the values of reliability parameters are determined and the influence of the type of failure distribution law on the reliability parameters is analysed, for the evaluation of the effectiveness of the TRS equipment maintenance organization. The ratios obtained at the same time make it possible to determine not only the reliability indicators of the system, but also to calculate the optimal frequency and timing of maintenance in order to maintain the reliability of the system.

Dental implants - are they better than natural teeth?

Nowadays, patients find much information on dental treatment from the Internet. There is a vast amount of information on dental implants, in contrast to the limited information available on natural teeth. This review addresses research on survival of natural teeth and dental implants, and discusses factors affecting the survival rate of implants, as well as certain dogmas in implant dentistry. To simplify treatment planning, the article presents a classification system in which teeth are classified as secure, doubtful, or irrational to treat. Secure teeth should last for a long period of time without need for complex treatment. Doubtful teeth are teeth that might need complicated treatment and additional maintenance in order to be maintained. Teeth irrational to treat are teeth that cannot be saved and for which extraction is the only treatment option. Multiple risk factors might decrease the survival probability of teeth. The survival and success rates of dental implants will never succeed the survival rates of healthy, clean teeth. Dental implants and implant-supported restorations are an excellent treatment modality, but it must always be kept in mind that it is associated with a risk of biological and technical complications. Implants are supposed to replace missing teeth - they are not supposed to replace teeth.

ANALISIS EFESIENSI DAN IDENTIFIKASI FAKTOR SOSIAL, EKONOMI DAN TEKNIS YANG MEMPENGARUHI KONVERSI USAHATANI JERUK KE USAHATANI KOPI DI KECAMATAN BARUSJAHE KABUPATEN KARO

The aim of this study are; a) to determine the efficiency level of citrus farming and conversion to coffee farming in Barusjahe District, b) to identify social, economic and technical factors affecting conversion of citrus farming to coffee farming in Barusjahe District, and this research uses descriptive data analysis method. The results of research are; a) average income level of citrus farming Rp. 14,867,110/ha/ year < average income of coffee farming Rp.17.675.996 /ha/ year, and efficiency of citrus farming (R/ C: 2.52) < efficiency of coffee farming (R/C: 4,43), b) Social factor that is public acknowledgment is the main reason of 33% of respondents to convert citrus farming to coffee farming. And the economic factor that is the price is the main reason 33.3% respondents, the conversion of citrus farming to coffee farming. As well as technical factors namely the maintenance process is the main reason for 56.67% of farmers respondents to convert citrus farming to coffee farming in Barusjahe District. Based on the research results suggested; a) for the government to conduct continuous counseling for farmers of coffee farming so that its production is increasing, b) so that citrus farmers do better maintenance and maintenance in order to optimize their production, c) so that farmers use pesticide in accordance with recommended dosage, to reduce the cost pesticides, d) for farmers to pay attention to the concept of sustainable agriculture in converting land from citrus farming to coffee farming in Barusjahe District so farmers' income can be sustainable.

Analysis of dissemination methods for remote sensing information in maritime field to support the local government

The demand for remote sensing imagery data has been increasing in recent years in Remote Sensing Technology and Data Center LAPAN, especially the utilization of such data for the maritime field. Data request is recorded increasing trend from 808 scenes in 2015 to become 6773 scenes in 2016. Therefore, Remote Sensing Technology and Data Center should improve its services so that information provided to users could be delivered as fast as possible. The objective of this research was to find the best alternatives dissemination from the current method of data distribution and remote sensing information in terms of speed, scalability, functionality and data maintenance in order to support government program on maritime sectors. Alternative to be examined was based on Web-GIS which means that access to data and remote sensing information could be done online through internet. The used of Web-GIS in this study due to the utilization of the internet already prevalent in the present day. Through this method, users could have obtained data and information from anywhere and anytime. As an example, this paper uses mangrove distribution data in Banten as remote sensing data provided. Results are easily obtained mangrove information; the government can overcome the problems that has emerged as the reduced area of mangrove forest which resulted in causing chain actions such as floods and other disasters. Using Web-GIS can be an effective means of dissemination to speed up service.