Heavy Maintenance Research Articles

A Valorized Scheme for Failure Prediction Using ANFIS: Application to Train Track Breaking System

In the rolling stock sector, the ability to protect passengers, freight and services relies on heavy inborn maintenance. Initiating an accurate model suitable to foresee the change of attitude on components when operating rolling stock systems will assist in reducing lock down and favors heavy productivity. In that light, this paper showcases a suitable methodology to track degradation of components through the blinding of physic laws and artificial intelligent techniques. This model used to foresee failure deterioration rate and remaining useful life (RUL) speculation is case study to showcase its quality and perfection, within which behavioral data are obtained through simulated models initiated in Mathlab. For feature extraction and forecasting issues, different neuro-fuzzy inference systems are designed, learnt and authenticated with powerful outputs gained during this process.

Development of a tool for access worktime estimation in aircraft maintenance

This study was aimed to find a way how to deal with hardly predictable circumstances while performing routine access works during aircraft heavy maintenance and to estimate the time spent with the work. The lack of maintenance data was crucial in dealing with this issue, therefore, additional measurements were necessary. For this purpose, this study was done in cooperation with Czech Airlines Technics Maintenance Repair Organization. The company currently estimates timing of panel manipulation based on the information contained in the manufacturer’s documentation. A database was established with work measurements of maintenance technicians accessing panels during real aircraft maintenance. They should by their nature reflect complications arising during the access panel manipulation and of the specific operational factors in the company. The main importance of the database lies in the creation of additional data to refine the aircraft maintenance planning estimates. Based on the measurements, it was possible to demonstrate that the access panel manipulation times as stated in the manufacturer’s documentation are only indicative. For each measurement performed, the measured overall time of panel manipulation was much higher than the equivalent time estimates by the manufacturer. During the measurements, several other factors were also discovered as causal to differences in the manipulation times. The database served as the basis for a developed software tool providing more accurate estimates of access panel manipulation times and resulting in more accurate estimates in maintenance planning in the Czech Airlines Technics, although the results are well reusable with other Maintenance Repair Organizations.

Program Designing the Improvement of Excavator’s Maintenance Team Competencies (Case Study in a Sandstone Mine Company PT XYZ)

The heavy equipment maintenance system cannot be separated from the problems of Human Resources (HR). Some literature has defined HR as a success factor for the successful implementation of maintenance systems. The Asset Maintenance Division as an organization which responsible to maintain the Company's assets routinely, including the Doosan S500’s 50-tonne class excavator. But in fact, excavators that are currently still operated often breakdown and its physical condition are in a bad condition. From the observation of 9 (nine) units excavators, the Key Performance Indicator (KPI) target was still not achieved, especially on the items Mean Time To Repair (MTTR) and Mean Time Between Failure (MTBF). Mechanic’s technical competencies needed in achieving KPI are divided into four sub competencies: Maintenance, Repair & trouble shooting, Remove & install and Overhaul. This study aims: analyzing mechanic’s competencies against company‘s standards, analyzing the influence of mechanic’s competencies on achieving KPI targets, providing recommendations on the influence of mechanic’s competencies for achieving KPI targets. The primary data used in the study were obtained through interviews and the questionnaires as well as secondary data obtained from various literatures, research results and supporting books. The method of processing and analyzing data uses the method of gap analysis and the Non-Parametric Statistics (Multiple Regression). The results of the gap analysis are known that there are still gaps in the actual competence of employees with competency standards set by the company. Factors that cause the competency gap are generally known because of a lack of understanding of the basic skills required, mastery of work techniques and consistency in applying work quality standards. Recommendations from this study as an effort to improve the skills and knowledge of mechanics to improve work effectiveness that affects MTTR and the quality of work that affects MTBF so that the KPI are consistently achieved

ФЛОРА ГАЗОНОВ ГОРОДА УФЫ

The paper presents a study in the flora of lawns in Ufa. The lawn flora is represented by 192 species belonging to 31 families. Based on coenotic and ecological characteristics, four ecological coenotic groups of species were singled out that were described in the lawn designated areas. The ecological coenotic groups were analysed for life form spectra, hemeroby, species activity. Among the plant communities of typical low-trampled and well-maintained urban lawns (the ecological coenotic group of Festuca pratensis) Poaceae, Asteraceae, Fabaceae, Rosaceae, Apiaceae families were the leading ones, where hemicryptophytes and oligo-meso-αeuhemerobes dominated. The lawns subjected to significant anthropogenic impact (trampling, salinization) (the ecological coenotic group of Taraxacum officinale) had a large number of species that belonged to the «ruderal» Polygonaceae, Asteraceae, Fabaceae, Brassicaceae, Lamiaceae families, where hemicryptophytes and meso-euhemerobes dominated. Ruderal species of Asteraceae, Poaceae, Amaranthaceae, Lamiaceae, Malvaceae, Polygonaceae families prevailed, with a large share of ruderal and semi-ruderal annual and biennial plants, β-eupolyhemerobes, in the lawn designated areas where gramineous plant community did not develop after soil disturbance (the ecological coenotic group of Chenopodium album). Ruderal species of Poaceae, Chenopodiaceae, Polygonaceae families with a large portion of ruderal annual and biennial β-eupolyhemerobes also dominated in humid and waterlogged lawn areas. The ecological ecoenotic groups of Taraxacum officinale, Chenopodium album and Bidens tripartita had a large number of neophyte species. The lawn areas with the ecological coenotic groups of Taraxacum officinale, Chenopodium album and Bidens tripartite were found as most colonized with ruderal plants. A number of measures are required to build dense grass covering: reconstruction and heavy maintenance of lawns combined with sowing quality lawn grass mixtures, regular mowing practices to reduce the number of ruderal hemytherophytes and therophytes, timely plant nutrition and watering.

A robust ink deposition system for binder jetting and material jetting

The adaptation of inkjet technology for additive manufacturing (AM) enabled the highest standards of print speed and print resolution in the industry. However, inkjet printheads impose strict limitations on ink properties. Ink compositions ex volatility, rehydration, surface tension, chemical stability, abrasiveness, and electrical properties that deviate from printhead specifications shorten its service life. Frequent and complex maintenance procedures are necessary, but replacement is the only solution to declining print quality, accruing heavy maintenance costs. This is especially limiting for AM as part quality and properties are closely dependent on ink composition. We propose an ink deposition system designed for robustness by implementing modular and dedicated components. The system deposits ink in a continuous jet. We find optimal process parameters and evaluate system performance in comparison to inkjet and material extrusion (ME). The system produces line widths between 0.3-0.5mm, indicating print resolution capabilities are comparable to commercial ME systems.

Secure Auditing and Intelligent Compression in Cloud

As the cloud computing technology develops throughout the decennary, externalising data to store using cloud resource becomes a trend, which is benefited in heavy data management and maintenance. Notwithstanding, since the externalized cloud depository is not fully reliable, while achieving integrity auditing it elevate security treat on how to realize single instance storage in cloud. In this work, we study the problem of integrity auditing and secure intelligent compression on cloud data. Peculiarly, directing at attaining both eliminating duplicate copies of repeating data i.e., secure deduplication and integrity of data in cloud, we propose an auditing entity with a perpetuation of a MapReduce cloud, which helps audit the integrity as well as uploading of data after clients generate data tags having been collected in cloud.

Is it Possible to Build a Profitable Maintenance Business in the Market of Heavy Medical Equipment in the B2G Segment?

The relevance of the study is defined by the dramatic situation associated with the new high-margin medical device market in Russian Federation. The study shows the industry practice of heavy medical equipment maintenance2 and challenges in shaping the business model in conditions of legislative and regulatory gaps, an objective deficit of qualified technical experts and the poor quality of maintenance at public healthcare. The relevance of the article is formed by the absence of formal and informal rules of market performance. There is no consentience neither in the legislative, executive and judicial authorities, nor among the healthcare managers, suppliers (including Company’s subsidiary in Russia) and consumers (healthcare sites) of complex medical equipment. The problem is also dramatized by the black-market spare parts supply in Russia and the trend to its validation by the authorities. It’s difficult to embrace the phenomenon, to define values and goals, and specify ethical and practical results. Low development of theoretical economy rules at the new market cause the uncertainty of business compliance in the Russian Federation. The purpose of the study is to identify the basic theoretical foundations at the emerging market of heavy medical equipment that have an impact on the development of this innovative sector of the economy. The research item is presented as a KeyKis and defined as follows: Is it possible to build a profitable maintenance business at the market of heavy medical equipment (HME) in the B2G segment and guarantee its high-quality in the situation of legislative loophole? The answers could serve as a basis for development the legislative provision and maintenance guidelines, as well for forming managerial and marketing strategies for the company. The research methods consist in examining this phenomenon in a particular challenging situation in time, space and interrelation of key participants of the emerging industry market, including public and private stakeholders, domestic and foreign businesses, responsible and irresponsible characters. The case study (KeyKis) is based on authoring tools of academic economy that are applied in practice: the product matrix, the market carotid (3-D economy model), the amplified marketing strategy matrix. The research results show the mutual influence of stakeholders on the new market branch of medical technologies and business development opportunities at the heavy medical equipment maintenance market in Russian Federation. The practical importance of the paper is to facilitate the definition of difficult economic situation, provide guidelines for strategic processing and apply these tools to practical management.

Maintrainenance: Keeping Heavy Rail Maintenance on Track

Infrastructure management is an important aspect of transportation engineering. Contrasting views have emerged on feasible best practice in asset management for various transportation modes. The differences in current practice can provide insight into best practices and lessons learned. This paper focuses on heavy rail maintenance state of practice in the United States and compares the maintenance practices, strategies, and procedures implemented by four transit agencies across the country. The objective of the paper is to provide guidance and examples for other transit agencies in the United States to meet the short-term challenges they face and provide recommendations to improve services nationwide. This paper examines rail maintenance practices at the Metropolitan Atlanta Rapid Transit Authority (MARTA), Bay Area Rapid Transit (BART), Washington Metropolitan Area Transit Authority (WMATA), and the New York Metropolitan Transit Authority (MTA). The paper found that out of the four agencies studied, MARTA has the highest maintenance to operations budget ratio, and most of the maintenance expenditure is on labor. WMATA found that automation of inspection improved maintenance efficiency, and BART is working toward adopting more automated processes. New York City’s MTA shows an example of the importance of clear governance in effective budgeting.

Evaluating Working Time and Work Capacity of Aircraft Cabin Line Maintenance Services

Along with the development of modernization and technology, high mobility has been transformed into the basic needs of each individual. To achieve high mobility, various kinds of transportation are highly needed, ranging from land, sea to air transportation. Aircraft as one of the main transportation, requires high maintenance costs to anticipate and minimize the risk of air accidents. Generally, aircraft maintenance can be divided into line maintenance that handles light (minor) maintenance and base maintenance that consist of heavy maintenance. One of the focuses on line maintenance beside of navigation and communication systems is Cabin maintenance. Cabin Maintenance Services usually perform the transit check, 24 hours check, daily check, weekly check, up to A Check. One of the focus of cabin maintenance is cabin standard check. Cabin standard check that consist of several checks from passanger aircraft entrance door, service door, cockpit interior, galley, lavatory, pessanger seats is currently allocated 150 minutes. However, it was found that with an allocation of 150 minutes by 1 man power, it was not possible to complete the cabin standard check for A330 series aircraft. Therefore, measurements of standard times andrestandardization for several types of aircraft is needed. Data collection is done by using a stopwatch time study to get the actual cycle time, then interview with mechanics on duty to get things that require an allowance, and consider the capacity of man hours and man powers available in the Maintenance Control Center (MCC). After measurement and recalculation, it was proposed to add another man power to the A330 series and proposed cabin standard check processing time for B737 series aircraft by 130 minutes, CRJ1000 by 95 minutes, and B777 and A330 using 2 manpowers each of 220 and 160 minutes to finish the Cabin Standard Check during cabin maintenance in various series of aircraft.

Heavy maintenance of concrete paved roads using the regional roads No. 102 and No. 142 as an example

The paper describes heavy maintenance projects carried out on two regional roads located in the West Pomerania region of Poland. The projects started in 2017 on two sections of these roads. Completely different methods were used on these two sections. On the regional road No. 142 in-place crushing, specifically the rubblizing technique was used over an almost 20 km long stretch of pavement. In the second case the old pavement was left in place and a layer of bituminous-aggregate mixture was placed to control reflective cracking. Pros and cons of these methods are presented in the paper, together with the problems noted during the works.

A Genetic Algorithm for Assigning Train Arrival Dates at a Maintenance Centre

Abstract The paper is concerned with planning heavy maintenance of train-sets at a maintenance centre. The heavy maintenance process is complex and, for each train-set, the actual duration of maintenance is uncertain at the time of planning. The allocation of the dates when train-sets should arrive at the maintenance centre is crucial phase of the planning procedure. The objective function is a weighted sum of two components, the expected total penalty for not meeting the required number of train-sets in active service and the total cost for the deviation (earliness and tardiness) from the desired dates of arrival. A genetic algorithm is presented for the considered problem and its effectiveness is demonstrated by the computational experiments that used real-world data provided by a big maintenance centre.

Research on Paraffin Deposition Law and Paraffin Removal-Prevention Technology of Rodless Lifting Wellbore

The rodless lifting technology can overcome the shortcomings of rod and tube wear, high energy consumption and heavy maintenance workload in the lifting process of rod pumps, which is gradually being developed and adopted by major oil fields around the world. However, the paraffin deposition is coming more and more serious duo to non-sucker rod disturbance in wellbore and the relatively slow flow rate of well fluid, the production and maintenance cost are increasing, the pump inspection cycle is shortened, which creates a bottleneck for the further popularization of rodless lifting technology. Therefore, the research and development of rodless lifting oil well paraffin removal-prevention technology is great significance to the application and promotion of rodless lifting technology. Based on the study of paraffin deposition in oil wells, the effects of paraffin content, fluid flow rate, gelatin, wall temperature and other factors on paraffin deposition in crude oil are analyzed, to discuss the internal relationship. By the laboratory tests, the mathematical model of paraffin deposition in rodless lifting wellbore is obtained. Field tests were carried out to verify the paraffin control effect of the developed solid paraffin inhibitor matched with the paraffin deposition law and mathematical model of rodless lifting wellbore. Field tests show that the period of heat-free washing of rodless lifting wells is more than half a year after the application of solid paraffin inhibitors, and the effect of paraffin control is obvious. The research and development of paraffin removal and prevention technology is of great significance to the popularization and application of rodless lifting technology. The research and development of paraffin removal-prevention technology is important for the popularization and application of rodless lifting technology.

A mathematical model and algorithms for the aircraft hangar maintenance scheduling problem

An aircraft hangar maintenance scheduling problem is studied, motivated by the aircraft heavy maintenance conducted in a hangar operated by an independent maintenance service company. The aircraft hangar maintenance scheduling problem in such context consists of determining a maintenance schedule with minimum penalty costs in fulfilling maintenance requests, and a series of hangar parking plans aligned with the maintenance schedule through the planning period. A mixed-integer linear programming (MILP) mathematical model, integrating the interrelations between the maintenance schedule and aircraft parking layout plans, is presented at first. In the model, the variation of parking capacity of the maintenance hangar and the blocking of the aircraft rolling in and out path are considered. Secondly, the model is enhanced by narrowing down the domain of the time-related decision variables to the possible rolling in and out operations time of each maintenance request. Thirdly, to obtain good quality feasible solutions for large scale instances, a rolling horizon approach incorporating the enhanced mathematical model is presented. The results of computational experiments are reported, showing: (i) the effectiveness of the event-based discrete time MILP model and (ii) the scalability of the rolling horizon approach that is able to provide good feasible solutions for large size instances covering a long planning period.

A hierarchical location service architecture for VANET with aggregated location update

For Vehicular Ad-Hoc Network (VANET) location services, scalability toward the extensive network scale and high mobility of vehicles is a key issue. Furthermore, minimization of signaling overhead is another important issue for emerging applications such as IoV (Internet of vehicles) which require frequent and continuous collection of location information. Some of the VANET location service mechanisms solely rely on per-vehicle server assignment and location updates, and thus, impose heavy server maintenance complexity and/or signaling overhead. On the other hand, there exist mechanisms that perform aggregated location updates based on hierarchical architecture. The legacy mechanisms with aggregated location update, though, either suffer lack of service reliability or cannot take full advantage of the location update aggregation in reducing the location update overhead. Accordingly, we propose a dynamic Mobile Group-based Location Service (MoGLS), a scalable VANET location service, which is robust to the mobility in terms of both reliability and overhead. MoGLS is based on a hierarchical structure of servers. The lower level is composed of dynamic groups of vehicles with similar trajectories, and one of the vehicles in each group takes the role of lower level location server. Higher level is comprised of the unit areas with an infrastructure-based fixed server. For the location update from the lower to the higher level server, aggregation of information is applied. By the leverage of characteristics that lower level servers move together with their member vehicles, mechanisms to prevent the deterioration of service reliability due to aggregated location update are proposed while taking full advantage of the aggregated location update in reducing the signaling overhead. MoGLS includes dynamic group management, location update and discovery, and a group merge algorithm for the optimal group formation. Through the performance comparisons via simulation, it is shown that MoGLS provides satisfactory service reliability with smaller signaling overhead compared to the existing hierarchical VANET location service mechanisms with aggregated location update. Furthermore, the performance of MoGLS is shown to be more stable toward the increase of density and speed of vehicles.

Removal and/or prevention of limescale in plumbing tubes by a radio-frequency alternating electric field inductance device

Fouling problems due to limescale formation are of major concern to many industries. Deterioration of heat transfer equipment performance and substantial increase of pressure drop across piping systems comprise the main problems, resulting in high machinery-maintenance cost and decreased productivity. Limescale removal techniques, like scraping, hydro-blasting, and the use of aggressive chemicals, shorten the life of pipes and machinery. Furthermore, limescale prevention techniques in industrial scale, like ion-exchange or reverse osmosis, require expensive equipment and heavy maintenance. In this paper, an electronic antifouling device is presented which, not only prevents limescale formation, but also removes existing scale in plumbing tubes, at insignificant energy consumption. Induction of a Radio-Frequency Alternating Electric Field (RFAEF) in water at a specific range of frequency and antenna voltage, along with its distinct sinewave waveform, changes the way minerals precipitate, minimizing hard-lime scale by producing instead a non-adherent mineral powder in the bulk water. Moreover, the unsaturated solution that is created, along with enhanced carbon dioxide production, dissolves gradually the existing scale in plumbing tubes. Furthermore, the RFAEF inductance device demonstrates a major improvement over other pulsed-power systems, proving this electronic antifouling technique suitable for both hard and soft waters, as well as for large-scale applications.

The Tunnel Structural Mode Frequency Characteristics Identification and Analysis Based on a Modified Stochastic Subspace Identification Method

With the rapid development of underground engineering in China, the heavy structural maintenance work followed is expected to be a great challenge in the future. The development also provides a promising application prospect for the newly developed vibration‐based health assessment and monitoring methods. However, the fact that tunnels are embedded in soil makes collecting and identifying the vibration characteristics more difficult, especially for the online monitoring. In this paper, a new identification method that combines the natural excitation technique (NExT) and stochastic subspace identification (SSI) method is developed. The new method is compared with the traditional SSI method, and mode frequency analysis is made based on a series of field tests carried out at the subway and power tunnel. It is found that both stability and efficiency of the mode frequency identification have been greatly improved, and it more suitable for online monitoring. Meanwhile, a mathematical model is used to analyze the original mode characteristics and the influence of soil coupling. The results are also compared with the field tests results by using the NExT‐SSI method, and some recommendations are also made for how to choose the vibration modals for vibration‐based monitoring in the tunnel.

Ekonomska analiza pojačanog održavanja državnog puta IB21, deonica Irig - Ruma

Ekonomska analiza pojačanog održavanja državnog puta IB21, deonica Irig - Ruma

Advanced imaging processing for extracting dynamic features of gas turbine combustion chamber

Many industrial and transportation applications use combustion in dedicated chambers. Combustion implies, depending upon the nature and the amount of precursors, production of carbon dioxide, pollutants and dusts in terms of particulate matters. With the aim of reducing emission, lean combustion is of great interest. However flame stability within the combustor chamber is a key issue under lean conditions. In fact under lean conditions burners exhibit flame instability, flashback or lean blow out, until the flame extinction. Hence the online monitoring of these phenomena related to combustion instability is essential. One the most used techniques is to check temperature and flame stability by means of sensing probes resisting to high temperatures. Increasing the number of probes, it is possible to perform a 2D and 3D monitoring. However since these probes are costly and require heavy maintenance procedures, it could be wise to exploit imaging processing through cameras directed to portholes across which we can see inner parts, and atmosphere of the furnace/chamber. This paper illustrates findings related to monitoring the flame behaviour different operating conditions chamber by an advanced image processing. A specific algorithm has been developed to characterize the flame, hence, to perform measurements. Myriad filters have been utilized to enhance flame features.

The challenges and limitations of magnetic resonance imaging technique in veterinary curriculum and clinical practice in Nigeria

As veterinary practice advances globally, the outcome of most treatments depends largely upon appropriate definitive diagnosis. Over the years projection radiography was the main imaging technique being utilised for radio-diagnosis of clinical conditions that would give the 2D images of a 3D structure and had narrow exposure latitude. However, with the advent of modern diagnostic techniques, such problems have been largely resolved. There are a number of imaging techniques like ultrasonography, computed tomography, nuclear medicine scintigraphy and magnetic resonance imaging that are currently available for clinical veterinary diagnosis. Each with its strengths and weaknesses. More than one technique therefore, may be used to compliment or supplement the findings of other techniques to arrive at a final diagnosis. The modern imaging diagnosis though well established in developed countries across the globe, it is yet to be embraced or remains in its infancy stage in veterinary curriculum and practice in Nigeria; due to heavy initial investment and maintenance costs, lack of professionals, requirements of specialized skilled technical staff to manage the machines and the need for adjustable machines to accommodate the different species of animal. This study presents a brief review and update of the development, challenges and status of a diagnostic imaging technique – Magnetic Resonance Imaging in veterinary medical curriculum and practice in Nigeria. Keywords : Clinical practice, Challenges, Limitation, Magnetic resonance imaging, Nigeria

Aircraft maintenance checks using critical chain project path

PurposeAircraft operators incur significant costs when an aircraft is taken out of service for maintenance. The purpose of this paper is to present a method for reducing time duration of aircraft maintenance checks using critical chain project management (CCPM) principle.Design/methodology/approachA case study of a typical heavy maintenance check performed on an Airbus 320 aircraft is undertaken for the analysis. The critical chain method is applied to develop a plan with a reduced duration and a survey and field observations to validate the findings have also been carried out as a part of this paper.FindingsThe paper compares the traditional project management method with CCPM in view of reducing the aircraft down time duration for maintenance. This paper repositions buffers and other techniques to shorten the chain path and a reduction in the total duration of the project by five days is achieved.Research limitations/implicationsIt is argued that the application of CCPM principle can reduce the duration of an aircraft maintenance check, but this paper is done in a single project situation focusing on project planning and execution. Therefore, additional study may be required to examine other issues.Originality/valueCost of the maintenance is second highest expenditure factor for an airline operator. Therefore, it is necessary to drive the maintenance cost down. The paper demonstrates that the duration of a maintenance check can be reduced by 8.9 per cent using the method suggested in this paper.