Designing a Medical Supply Chain Network Considering the Risk of Supply and Flexible Production in Two-Stage Uncertain Conditions

In the green supply chain approach, all the links that are put together to provide a product or service are considered, and strategic and operational decisions are made to increase the efficiency and effectiveness of the entire chain. At the same time, the environmental effects should be minimized. In this research, a nonlinear mixed-integer multiobjective model is developed to design a green closed-loop supply chain for medical products. In this supply chain, the echelons include supplier, manufacturer, warehouse, and customer in the forward supply chain and collection centers, repair services, and disposal centers in the reverse supply chain. In the proposed model, four objectives of customer satisfaction, environmental effects, supply risk, and total costs of the supply chain were considered. The developed model is implemented in a supply chain of medical products, and after optimizing the model, the main results including location and capacity of facilities, planning for flexible production, purchase of materials, service and maintenance plan, product transfer, and inventory level are determined and analyzed.

PLANNING AND SCHEDULE OF MAINTENANCE WORKS FOR INJECTION MACHINES

Keeping the equipment and machinery in working order is a very important activity in the field of industrial production, being specific to the maintenance department within an enterprise. Ensuring an optimal in operation of the manufacturing systems is closely related to the prevention of defects, an action that must be found in a planning and scheduling of preventive-planned maintenance works. In the paper, in addition to the introductory part on the main objectives and implementation of the maintenance system and maintenance-specific operations, a case study is conducted for the planning and organization of maintenance in a company equipped with plastic injection machines. The main stages developed consisted in elaborating the maintenance plan, establishing the optimal moment for replacing the machine tools, choosing the optimal type of machine tool and establishing the elements of random wear of the machine tools. It is concluded that the optimal type of injection molding machine that will be chosen to replace the T10 injection molding machine is T14, because it has a minimum average cost of acquisition, maintenance and repair, respectively 42.286 UV.

Optimal Policies of Social Infrastructures Maintenance using Shock and Damage Model

Social infrastructures such as roads and bridges are indispensable for our lives. They have to be maintained continuously and such maintenance has become a big issue in Japan. Social infrastructures are maintained under strict restrictions such as decreasing in local finance revenue and scarcity of skilful engineers. Various kinds of factors such as inspection periods, maintenance costs, and degradation levels, are necessary to consider in establishing efficient maintenance plans of social infrastructures. Furthermore, the special circumstances of social infrastructures such as the delay of constructions which is caused by the scarcity of budget, must be discussed for the efficient maintenance plan. For such discussion, the stochastic cost model which contains preventive and corrective maintenances is useful. Although these models have been studied in mechanical and electronic systems, unique characteristics of social infrastructures such as their enormous scale and delays due to maintenance budget restrictions must be considered when such social infrastructure models are discussed. In this paper, we establish maintenance models of infrastructures which some of preventive maintenance must be prolonged. The expected maintenance cost rate is established using the cumulative damage model and optimal policies which minimizes them are considered. Three basic models and their extended models which consider natural disasters are discussed.

RCM 3 Methodology Application to Armored Military Vehicle Cooling System

The ultimate goal of developing the future of Reliability Centered Maintenance is to introduce the RCM3 methodology, applied in this article to the cooling system of high-performance military armored vehicles fleet, used in current operation theaters. This methodology is not only more advanced and aligned with the international standards for physical asset management and risk management, but also allows users to fully understand and quantify the associated risks, focused on the reliability of the systems. The case study aims to obtain a proposed maintenance plan to the vehicle’s cooling system. Methods such as the distribution of Weibull applied to reliability and Right Censored Data, were used for the calculation of MTBF (Mean Time Between Failures). The results of the study confirm the possibility of using the proposed methodology to evaluate the operational reliability of the high-performance military armored vehicles fleet in any armed forces. The maintenance plan obtained with RCM3 proves to be more suitable and capable of reducing the risk associated with the system failure modes.

Analysis of the Repair Time of Finishing Works Using a Probabilistic Approach for Efficient Residential Buildings Maintenance Strategies

In general, the long-term maintenance planning of residential buildings is performed based on uniform repair times. However, in fact, various factors, such as the quality and user patterns, affect the performance of residential building components in the Operation and Maintenance (O&M) phase. Hence, various residential building components are repaired at uncertain times, acting as a risk for the residential building maintenance plan. Therefore, an efficient maintenance plan should be established considering maintenance uncertainty. In this regard, this study aims to analyze the uncertainty of repair times for various finishing works in residential buildings based on a probabilistic methodology and outline the implications for the establishment of efficient maintenance strategies in these buildings. Hence, 47,344 repair data for 63 buildings in 12 public residential building complexes completed between 1991 and 2001 in the Republic of Korea were used for analysis. Before the analysis, a repair time matrix was constructed by classifying the finishing works in 25 types and setting service life times to 6–26 years. The repair time distribution for each finishing work was then derived. Results confirmed that basic repair time setting can be performed and various information for reasonable maintenance decision making regarding each finishing work can be provided through a probabilistic approach. The probabilistic approach can be used as a critical decision-making method because there is uncertainty associated with the repair time of each finishing work owing to the performance degradations of various finishing works due to complex causes. Although this study focused on repair time owing to data collection limitations, maintenance strategies with strategic flexibility can be established by developing probabilistic methods that simultaneously consider frequency and cost by securing additional high-quality cost data.

Improving quality of maintenance task for milk powder manufacturing unit through TOPSIS

PurposeThe purpose of this paper is to explore the possibilities of improving the quality of existing maintenance task of the atomizer of milk powder manufacturing unit of a dairy plant. Looking to the past business volume and expected growth, the milk powder manufacturing unit forms a noticeable sector of processing plant. The lack of quality in maintenance standards leads to reliability losses of about 20–25% with low productivity and profit. Such facts and challenges of keeping the system in ready-state motivate a definite maintenance plan to be modeled based on a live failure analysis to be executed during shutdown or scheduled period.Design/methodology/approachThe deliverables are achieved by collecting the historical failure data i.e. downtime and failure frequencies; from January 2020 to July 2020 at Dudhsagar dairy, Gujarat, India. Reliability modeling is done in a view to understand the failure pattern behavior of the milk powder manufacturing unit. The atomizer is discriminated as a critical component based on these data and their functional failures, failure causes, effects and repercussions of failures with existing control and maintenance practices has been modeled based on live shop-floor study. Scores are assigned on 1 to 10 levels by analyzing attributes effects from lowest to highest concern respectively for every modes of failure through realistic brain-storming among maintenance team by incorporating some advanced attributes like maintainability, economic safety, economic cost and spares with basic criteria in this study. The maintainability criticality index (MCI) is narrated by these score values through multi-attribute decision-making (MADM) based failure analysis models like Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS).FindingsThe primary findings of this research work are to propose improvements in the quality of the maintenance plan of critical component like; atomizer of a milk powder manufacturing unit which is commonly representing critical component in a major range of industrial processes. The case study recommended four silent maintenance strategies i.e. scheduled maintenance scheduled discard, scheduled failure finding and redesign as a qualified maintenance plan for the atomizer based on MCI and rankings of its potential failure causes. The results are helpful in upgrading quality standards for the maintenance activities of a process industry of alike or of dissimilar kinds in accordance with the failure analysis.Originality/valueOriginality mainly consists of investigating the scope of enhancing the existing maintenance practices through actual failure analysis with the help of TOPSIS. The criteria employed in this study are probability of chances of failure, degree of detectability and degree of severity as basic criteria along with some advanced criteria like; maintainability, spare parts, economic cost, economic safety are selected based on the outcome of shop-floor study and reliability modeling. The notable past failure statistics (downtime, frequency of failures) of a milk powder manufacturing unit were recorded and these data are analyzed based on reliability to extract an explicative component i.e. atomizer.

Structural Soundness of Carpio Hall and Federizo Hall: Inputs for planning and renovation of buildings in Bulacan State University

The study focused on determining the structural soundness of Carpio Hall and Federizo Hall in Bulacan State University-Main Campus. The parameters used were the age of the building, material used, existing condition, and the compressive strength of the beams, columns, and slabs of the two buildings. The processes and tests that involve include visual inspection, non – destructive testing, hypothesis testing, and interview. The performance of non-destructive testing, particularly Hammer Rebound Test is to determine the compressive strength of each structural member followed by hypothesis testing to establish the significance of the compressive strength in each floor level. Based on the results, a Structural Audit Plan for Carpio Hall and Federizo Hall was proposed. It may be used as a basis in allocating a budget for the repair, retrofitting, and renovation. Some of the structural members of Carpio Hall and Federizo Hall already manifest signs of deterioration due to its age and improper maintenance. It is necessary to conduct visual/tapping observation to monitor the changes in the building and easily determine what members need repair. The use of non – destructive equipment like hammer rebound test is efficient in providing immediate test result and advisable to be of use as it will not contribute in the further damage of members. It is advisable to conduct a structural audit of buildings regularly or as needed to avoid more damage. Structural Audit Management Plan is also necessary as it will help in providing preventive maintenance plan to increase the service life of a building.