Replacement Of Components Research Articles

Development of a novel full-scaled self-centering brace with notched steel tubes

A novel self-centering brace with notched steel tubes (SCB-NST) was developed and experimentally studied. The proposed SCB-NST consists of a novel notched steel tube (NST) for energy dissipation and disc springs for self-centering, respectively. Three full-scaled specimens were tested to investigate the hysteresis behavior under cyclic loading. These specimens include a brace with NST only, a brace with disc spring only, and an SCB-NST. The first two tests were specifically conducted to obtain the contributions of the NST and disc springs alone, respectively. The test results illustrate that the first proposed NST displays excellent energy dissipation and deformation capabilities. The proposed SCB-NST exhibits a stable flag-shaped hysteresis behavior, distinguished self-centering, and significant energy dissipation capacity without residual displacement. Furthermore, experimental findings reveal that the disc spring functions as a secondary defense line of the SCB-NST system upon sudden failure of the NST. The cyclic test of the brace with disc spring only shows that the friction between the disc springs should not be neglected, especially when quantities of large-diameter disc springs are stacked. The modular design of the proposed SCB-NST facilitates the replacement of energy-dissipating components, allowing for efficient maintenance and ultimately achieving the design objective of promoting reusability and resource conservation. The SCB-NST, equipped with two NSTs featuring different ultimate displacements, has been confirmed through finite element analysis to have three defense lines, which improves the reliability and redundancy of the SCB-NST system. The parametric finite element analysis results reveal that the thickness of the energy-dissipation ring has the most significant influence on the load-bearing capacity and energy-dissipation capability of the SCB-NST. Concurrently, the pre-pressed force of the disc spring is crucial for eliminating the residual displacement of the SCB-NST.

Seismic performance of steel braced frames equipped with dissipative replaceable components

The structural performance of steel braced frames equipped with a new typology of dissipative replaceable components (called DRBrC) is analyzed and compared to the one of a traditional Concentrically Braced Frame (CBF) with diagonal-tension-only braces, highlighting pros and cons of the different solutions. The main benefit of the proposed system lies in the easy replacement of the damaged dissipative components after the earthquake, allowing to speed up retrofit operations without stopping the activities inside the building. The results of low-cycle assessment and life cycle cost analysis performed in the framework of the European research project DISSIPABLE confirmed the economic and environmental convenience of the system for repairing operations after seismic events. In the present work, two case study buildings, owing the same geometry and designed for the same loads with and without DRBrC devices, are analyzed and compared in terms of overall seismic performance, relevant parameters versus Intensity Measure (IM) indicators and fragility curves. An in-depth dissertation about design criteria, numerical modelling techniques and analysis procedures in the nonlinear field to be used for the DRBrC frames is provided.

Reclamation potential in the built environment: A method and metric for assessing environmental benefits beyond first use

Direct reuse and recycling of materials can significantly reduce the net environmental impact of the global construction sector. The feasibility of reuse and recyclability of building systems is affected by the materials used and the interfaces between constituent components. Yet there is a lack of quantitative methods for assessing the environmental benefits of alternative recovery strategies for multi-component and multi-material systems over the building lifetime. In this work, a novel assessment method was developed to enable a systematic and quantitative evaluation of the transient environmental reclamation potential (RP). The reclamation potential is a measure of the ability to disassemble and reuse recovered building systems at their end-of-life and is influenced by the constituent components and the interfaces between components. The proposed method accounts for the technical service lifetimes of components, including performance degradation over time, and can thus inform decisions on the most suitable recovery route for new and existing designs. The graphical outputs from the RP assessment are a network diagram which highlights the system components and connections between components, and an RP-graph which illustrates the embodied environmental impact and reclamation potential over time of alternative reuse/recycling strategies. The methodology is demonstrated on a glazed double-skin façade where the influence of component service lifetimes and replacements over time is quantified in terms of embodied energy and embodied carbon. The outcomes of the assessment can guide decision-making in design for disassembly (DfD) strategies and/or aid in the identification of high-value material recovery strategies at the end-of-life stage.

An optimization model for determining cost-efficient maintenance policies for multi-component systems with economic and structural dependencies

In most multi-component systems, the cost-efficiency of maintenance policies depends on technical structural dependencies. Motivated by the recognition that these dependencies must be accounted for in the development of optimal maintenance policies, we develop an optimization model to determine cost-efficient maintenance schedules for multi-component systems. Our main contribution is twofold. First, we introduce directed graphs as an expressive tool to represent the economic and structural dependencies of the system, including situations in which the maintenance of a given component may require other components to be disassembled or maintained. Second, we formulate a Markov Decision Process model, which is solved through the modified policy-iteration algorithm to determine the most cost-efficient policy. This policy indicates which maintenance actions consisting of disassembly and component replacement decisions are optimal when mandatory replacements must be made whenever the system fails, or the reliability of the system falls below a predefined reliability threshold. To our knowledge, this is the first model that provides optimal maintenance policies that comply with reliability requirements in the presence of constraints arising from technical structural dependencies. We illustrate the model with a realistic case study on the development of cost-efficient maintenance policies and show that its results compare favorably with heuristic maintenance policies.

Two Distinct Transitions in a Population of Coupled Oscillators with Turnover: Desynchronization and Stochastic Oscillation Quenching.

Synchronization, which is caused by mutual coupling, and turnover, which is the replacement of old components with new ones, are observed in various open systems consisting of many components. Although these phenomena can co-occur, the interplay of coupling and turnover has been overlooked. Here, we analyze coupled phase oscillators with turnover and reveal that two distinct transitions occur, depending on both coupling and turnover: desynchronization and what we name stochastic oscillation quenching. Importantly, the latter requires both the turnover and coupling to be sufficiently intense.

A novel slit damper configuration to enhance ductility and seismic behavior of concentrically braced frames

Steel slit dampers are the specific type of metallic yielding dampers used for the structural passive control. They are constructed by introducing a series of openings or slits in a steel plate to control the seismic behavior of structures. These dampers absorb energy through shear yielding, flexural yielding, or a combination of both. In this paper, a new form of steel slit damper is introduced and examined. The novel damper, called the Zipper-shaped Slit Damper (ZSD), is composed of two nested boxes connected through high-strength bolts. There are several steel strips in an external box and L-shaped profiles to prevent out-of-plane buckling, maximize flexural capacity, and ensure optimal lateral force distribution. Additionally, L-shaped profiles are welded to the ends of the steel strips. To assess the structural capacity and seismic behavior, ZSD is modeled in three dimensions using ABAQUS finite element software. The model is first validated against experimental results and then subjected to cyclic nonlinear static analysis, comprising 15 models with different width-to-thickness and height-to-width ratios of steel strips. The failure index (FI), based on equivalent plastic strain, is employed to predict the moment of failure. The results obtained from the FI were analyzed, and the analysis was limited until the moment of the first failure. On average, the novel damper demonstrated improved durability with an increase in the height-to-width ratio, resulting in enhanced ductility up to 8.75. Additionally, within each width -to-thickness ratio group, a 0.5 unit increase in this ratio corresponded to a reduction of approximately 10 % in energy dissipation efficiency. The equivalent viscous damping in the models averaged 42 %. The analysis indicated that all models exhibited stable hysteresis cycles and had high ductility and energy dissipation. Also, considering the obtained results, it can be concluded that the ZSD, due to its replaceable components, ease of construction, and easy installation, can be utilized in concentrically braced frames. Mechanical models, as well as stiffness and force relationships for design and implementation in braced frames, are presented. The findings provide valuable insights for the utilization of this innovative damper in seismic-resistant structural systems.

Assessing focal spot alignment in clinical linear accelerators: a comprehensive evaluation with triplet phantoms.

A fundamental parameter to evaluate the beam delivery precision and stability on a clinical linear accelerator (linac) is the focal spot position (FSP) measured relative to the collimator axis of the radiation head. The aims of this work were to evaluate comprehensive data on FSP acquired on linacs in clinical use and to establish the ability of alternative phantoms to detect effects on patient plan delivery related to FSP. FSP measurements were conducted using a rigid phantom holding two ball-bearings at two different distances from the radiation source. Images of these ball-bearings were acquired using the electronic portal imaging device (EPID) integrated with each linac. Machine QA was assessed using a radiation head-mounted PTW STARCHECK phantom. Patient plan QA was investigated using the SNC ArcCHECK phantom positioned on the treatment couch, irradiated with VMAT plans across a complete 360° gantry rotation and three X-ray energies. This study covered eight Elekta linacs, including those with 6 MV, 18 MV, and 6 MV flattening-filter-free (FFF) beams. The largest range in the FSP was found for 6 MV FFF. The FSP of one linac, retrofitted with 6 MV FFF, displayed substantial differences in FSP compared to 6 MV FFF beams on other linacs, which all had FSP ranges less than 0.50mm and 0.25mm in the lateral and longitudinal directions, respectively. The PTW STARCHECK phantom proved effective in characterising the FSP, while the SNC ArcCHECK measurements could not discern FSP-related features. Minor variations in FSP may be attributed to adjustments in linac parameters, component replacements necessary for beam delivery, and the wear and tear of various linac components, including the magnetron and gun filament. Consideration should be given to the ability of any particular phantom to detect a subsequent impact on the accuracy of patient plan delivery.

Beta diversity of restored river dike grasslands is strongly influenced by uncontrolled spatio‐temporal variability

AbstractAimsUnderstanding the spatio‐temporal patterns of restoration outcomes is crucial to improve predictability of restoration. High beta diversity of species‐rich communities is sought because it increases overall biodiversity and improves ecosystem stability and multifunctionality. For predictive restoration, it is important to identify the significance of drivers like site characteristics but also uncontrolled factors such as spatial effects, historical factors, and year effects.LocationDikes at river Danube, SE Germany.MethodsWe studied dike grasslands 4–19 years after restoration over five years (2017–2021, 41 plots in 12 sites). We calculated beta diversity indices to describe spatial variation and temporal turnover, including their additive components ‘replacement’ and ‘nestedness’, or ‘gains’ and ‘losses’. We analysed the main drivers of beta diversity like local site characteristics, landscape, and historical factors.ResultsSpatial variation of the restored dike grasslands was dominated by the replacement component and showed no homogenisation despite a significant temporal turnover. The replacement drivers changed over time, although replacement was mainly affected by slope aspect and landscape factors. Historical factors were inconsistent over time, and no statistically clear drivers of nestedness were found. The dike grasslands exhibited a year‐to‐year turnover in species composition of 37 ± 11%. Gains and losses were balanced over time, although the ratio changed and was most pronounced on south‐facing slopes.ConclusionsThe restored grasslands exhibited spatial variation by site characteristics but also by spatial factors which were not controlled by restorations. Moreover, high non‐directional temporal turnover occurred, caused most likely by weather fluctuations, slightly varying management, and stochastic biotic dynamics. Thus, flexible targets are recommended for restoration monitoring, by defining a set of desired states within a certain range. Furthermore, the dominance of the replacement component of spatial variation should move the focus from defining one precise restoration approach to defining a set of possible methods which together would foster beta diversity.

Incremental minimum distortion embedding for online structural damage classification.

The damage detection problem in structures diminishes the maintenance cost and extends the life of the structures. Online structural damage classification is a relevant topic in structural health monitoring since monitoring the structure using sensors can help decision-makers can rely on empirical evidence for making informed choices regarding the maintenance, repair, or replacement of structural components. Sensors generate high-dimensional data. To address this challenge, employing dimensionality reduction methods becomes essential. These methods help obtain a low-dimensional representation of the data. Traditional dimensionality reduction methods are trained on a fixed data set, and incorporating new data may require retraining the entire model. This study employed the Minimum Distortion Embedding (MDE) method incrementally, ensuring the maintenance of a consistent embedding as new data becomes available. This incremental embedding took advantage of an anchor constraint to pin the existing embedding in place, then embed the new points. An online structural classification methodology was developed using the incremental MDE and a stream based hoeffding tree classifier. Stream data processing differs from batch processing, as it involves the real-time consumption of each incoming data. The developed methodology was tested with data obtained by accelerometers in a laboratory scaled jacket-type wind turbine foundation. The structural damage classification problems had 5 different classes including the undamaged class and 4 different damage classes. The damage corresponded to a 5mm crack in four different structural elements of the wind turbine foundation. The results indicate the good behavior of the damage classification methodology supported by the high values of the classification metrics obtained.

Determination of the possibilities of using the universal low-temperature rotary apparatus for the production of meat and vegetable products under the conditions of providing uniform heat supply

The object of research is the process of frying a meat-vegetable product in the developed universal low-temperature rotary apparatus. The problem of ensuring the uniformity of the temperature field during low-temperature processing of meat and vegetable products is solved in the developed universal low-temperature rotary apparatus. The expected effect during the approbation of the apparatus is predicted under the condition of eliminating high-temperature intermediate coolants (hot air, etc.) due to the use of a film-like resistive electronic heater of the radiating type. The temperature field is established, which confirms the uniformity of the temperature effect on meat and vegetable products, and a slight deviation within the limits of autonomous exhaust fans is not critical and within the permissible error. Also, the introduction of Peltier elements into the design of the rotary apparatus will allow converting thermal energy into a low-voltage supply voltage (3–6 W) and, already at 20 °C, ensure autonomous operation of fans. The obtained results in the form of practical implementation of the developed apparatus will allow to implement low-temperature processing of meat and vegetable products. This allows to maximally preserve the functional properties of meat raw materials and the physiological properties of vegetable semi-finished products with a high degree of readiness. The practical implementation of the universal low-temperature rotary apparatus from the side of constructive implementation due to the use of functional containers makes it possible to obtain a wide range of assortment of meat products, both in the shell and without the shell. The elimination of high-temperature intermediate heat carriers (hot air, steam, etc.), their technical networks and generating apparatuss ensures energy and metal-intensive resource savings. In addition, the introduction of multicomponent vegetable semi-finished products of a high degree of readiness (powders, pastes, etc.) into the recipes of meat products will lead to a partial replacement of the main recipe components and an increase in the functional properties of the finished products.

RESEARCH OF AEROSOL APPLICATION SYSTEMS FOR APPLYING LUBRICATING MATERIAL IN THE «WHEEL-RACK» CONTACT

The article discusses various methods of lubricating the «wheel-rail» contact zone aimed at reducing friction coefficient and improving the efficiency of energy resource utilization, safety of movement, and environmental indicators. Technologies for delivering lubricating materials to this zone, such as lubricating rods, stationary systems using brushes, or railhead applicators, are outlined. The article highlights issues with existing technologies, including excessive lubrication, the need for component replacements, high lubricant material consumption, and uneven or incorrect application. It is emphasized that precision in the application and dosage of lubricating material is crucial to prevent its transfer onto the wheel and rail surfaces, which could reduce traction. The aerosol method of applying lubricant to the wheel edge is stated to be more accurate and cost-effective. The article mentions the company «SKF» and their EasyRail systems utilizing nozzles with the SP9-2 and SP9-2-S7 metering valves. Schematic representations of the nozzle and its working principle are provided. Sécheron is also mentioned, offering a nozzle for spraying lubricant onto the wheel edge through a two-tube system for oil and oxygen supply. An image of this company's nozzle is included. The text delves into the equipment of the lubrication system by Sécheron, specifically detailing the product's technical characteristics. Information about the development and manufacturing of the locomotive wheel flange lubrication system by the company "Scientific and Production Firm «Yugtekhnotrans» is presented. The article introduces the TrainSys-AL system for lubricating the rail head/running surface, providing a detailed description of its features and technical specifications, including the use of friction modifiers «HeadLub 90» and «RailLub». The products of the company Dropsa are mentioned, specifically the spray valve of the 1132330 series for the lubrication system of railway rolling stock and tracks. The overall context of the text is oriented towards the technical aspects and features of modern lubrication systems in railway transport.The study reviews existing designs of rail and wheel lubrication devices, revealing that there is no ideal design that meets all requirements for material consumption and precision in applying lubricating material. Consequently, a new nozzle for aerosolized oil spray is developed, and a laboratory setup for researching this process is manufactured. The setup operates on compressed air and includes a compressor with a reservoir tank for stabilizing nozzle operation. The hydraulic scheme of the setup is described, with key elements such as a ball valve, pressure reducing valve, pressure gauge, tank, and nozzle. The preparation of the setup for operation and its functioning principle are demonstrated. Research results indicate that the developed setup effectively sprays both dense and liquid lubricants depending on the air pressure and nozzle diameter. Graphs illustrating lubricant consumption for different types of lubricants and various nozzle parameters are provided.

Life Cycle Assessment of an Office Building in Finland Using a Custom Assessment Tool

Life cycle analysis (LCA) is a crucial instrument in the construction industry, offering a comprehensive evaluation of the environmental impacts at every stage of a building’s lifecycle. Recently introduced into Finnish construction legislation, this approach has not yet been thoroughly researched in relation to the Finnish Ministry of the Environment (FMoE) assessment method, nor have new calculation techniques been proposed to address its shortcomings. Furthermore, Finnish research on environmental impact assessment has predominantly focused on residential buildings, leaving a scarcity of studies on office buildings. This paper aims to fill these gaps in the literature, considering LCA, carbon footprint, and carbon handprint assessment tools of concrete-, timber-, and steel-framed cases. Our results are as follows: (1) the majority of the carbon footprint of a concrete-framed case originated from emissions associated with energy use and second largest share of total emissions occurred during the product phase of the building and within this phase, the building services contribute the most to product-related emissions; (2) a significant portion of these emissions came from facades and floor structures; (3) the carbon footprint of the timber-framed option was significantly lower than that of its concrete- and steel-framed counterparts; (4) steel-framed option’s carbon footprint was nearly equivalent to that of the concrete-framed option; (5) estimated carbon handprint of the timber-framed option was considerably higher than that of the concrete- and steel-framed options, primarily due to the carbon storage capacity of the timber components; (6) steel-framed option’s carbon handprint surpassed that of the concrete-framed option because of the high recycling and reuse potential of steel components; (7) the LCA method used by FMoE has some unclear areas. These ambiguities include how to assess the impacts of carbonation in cement-based products and the replacement of building components.

Sensing area-variable electrode for wide-range droplet size detection

Microfluidic droplets of various sizes are applied in a broad spectrum of biological and chemical processes and require high uniformity for reliable outcomes. Although various droplet detection methods have been employed to achieve monodisperse droplets, the capacitive method stands out for its ease of use and rapid response, enabling real-time feedback control. However, this method has limitations in terms of significantly altering the droplet size, resulting in increased continuous phase consumption and the need for microchannel and sensing component replacements. In response, we present the Sensing Area-Variable Electrode (SAVE), which is designed to produce monodisperse droplets across a broad size range without excessive continuous phase consumption and without requiring the frequent replacement of sensing components. The experimental results demonstrate that using the SAVE electrode enables the generation of monodisperse 0.2, 0.4, and 1.0 nL droplets by simply replacing the disposable microchannel while reusing the sensing components. Moreover, the adaptable number of droplets achieved by microchannel replacement allows the SAVE electrode to be effectively utilized in droplet digital polymerase chain reaction (ddPCR) assays, providing a balance between sensitivity and throughput. Consequently, the SAVE electrode addresses the limitations of the capacitive detection method and offers a versatile solution for various droplet-based biological and chemical processes, including ddPCR assays.

Optimizing the decarbonization of a geographically dispersed building portfolio

Many organizations are actively pursuing decarbonization goals to help mitigate the effects of climate change. This situation often requires capital replacement of building components with different fuel or higher efficiency variants to reduce emissions. However, this problem is complicated when an organization operates across a wide geographic area due to regional differences in weather, utility costs, and electrical grid emissions. This paper develops a framework for this problem by implementing energy, emissions, cost, and decision models that can scale across large organizations. The resulting decisions show the ability to reach decarbonization goals with lower costs and better rates of return. Compared to condition or unit-capacity ranking strategies, case studies show that the developed model reduces emissions by as much as 68.99 % or costs by as much as 47.08 %, depending on organizational goals.

Seismic fragility and resilience assessment of steel frame with replaceable T-stub connection components

Based on a rational design, steel beam-column joints with replaceable T-stub connection components (SBCJ-RTCCs) possess superior structural fuse performance and seismic resilience performance. To further evaluate the benefits of steel frames using RTCCs in terms of dynamic response, structural and non-structural components damage as well as seismic resilience, a 12-story steel frame equipped with RTCCs (SF-RTCCs) and a steel moment resisting frame (SMRF) were designed and established. On the basis of validating the simulation results with the experimental findings, the nonlinear dynamic analyses and incremental dynamic analysis (IDA) based seismic fragility analysis was performed. The results confirm that the introducing RTCCs into steel frames can significantly mitigate base shear and floor acceleration as well as produce a more uniform inter-story deformation and a more rational yielding mechanism. Meanwhile, the SF-RTCCs can obtain comparable collapse-resistant performance compared to SMRF, and both frames possess sufficient redundancy to resist structural collapse. Thanks to the lower floor acceleration responses, the SF-RTCCSs performs much better than SMRF in controlling non-structural components damage. After DBE excitations, the probabilities of RTCCs can be replaced by 1st class and 2nd class was 17.2 % and 84.9 %, respectively. After MCE excitations, RTCCs has about 29.3 % and 67.2 % probability that it can be replaced by 2nd class and 3rd class, respectively. Considering the lower economic losses, short repair time and fewer casualties, the rating of seismic resilience of SF-RTCCs was enhanced from one-star of SMRF to two-star.

Dissimilarity in flea and host assemblages and their interaction networks along a spatial distance gradient: different patterns revealed by different network dissimilarity metrics.

We investigated the distance-decay pattern (an increase in dissimilarity with increasing geographic distance) in regional assemblages of fleas and their small mammalian hosts, as well as their interaction networks, in four biogeographic realms. Dissimilarity of assemblages (βtotal) was partitioned into species richness differences (βrich) and species replacement (βrepl) components. Dissimilarity of networks was assessed using two metrics: (a) whole network dissimilarity (βWN) partitioned into species replacement (βST) and interaction rewiring (βOS) components and (b) D statistics, measuring dissimilarity in the pure structure of the networks, without using information on species identities and calculated for hosts-shared-by-fleas networks (Dh) and fleas-shared-by-hosts networks (Df). We asked whether the distance-decay pattern (a) occurs among interactor assemblages or their interaction networks; (b) depends on the network dissimilarity metric used; and (c) differs between realms. The βtotal and βrepl of flea and host assemblages increased with distance in all realms except for host assemblages in the Afrotropics. βrich for flea and host assemblages increased with distance in the Nearctic only. In networks, βWN and βST demonstrated a distance-decay pattern, whereas βOS was mainly spatially invariant except in the Neotropics. Correlations of Dh or Df and geographic distance were mostly non-significant. We conclude that investigations of dissimilarity in interaction networks should include both types of dissimilarity metrics (those that consider partner identities and those that consider the pure structure of networks). This will allow elucidating the predictability of some facets of network dissimilarity and the unpredictability of other facets.

Particle swarm optimization for a hybrid freight train powered by hydrogen or ammonia solid oxide fuel cells

All diesel-only trains in the UK will be phased out by 2040. Hydrogen and ammonia emerge as alternative zero-carbon fuel for greener railway. Solid Oxide Fuel Cells (SOFCs) provide an alternative prime mover option, which efficiently convert zero-carbon fuels into electricity without emitting nitrogen oxides (NOx), unlike traditional engines. Superior to Proton Exchange Membrane Fuel Cells (PEMFCs) in efficiency, SOFCs fulfil MW-scale power needs and can use ammonia directly. This study investigates innovative strategies for integrating SOFCs into hybrid rail powertrains using hydrogen or ammonia. Utilizing an optimization framework incorporating Particle Swarm Optimization (PSO), the study aims to minimize operational costs while considering capital and replacement expenditures, powertrain performance, and component sizing. The findings suggest that hybrid powertrains based on ammonia-fueled SOFCs may potentially reduce costs by 30% compared to their hydrogen counterparts, albeit requiring additional space for engine compartments. Ammonia-fueled SOFCs trains also exhibit a 5% higher efficiency at End-of-Life (EoL), showing less performance degradation than those powered by hydrogen. The State of Charge (SoC) of the batteries in range of 30–70% for both cases is identified as most cost-effective.

The Implementation Of Innovation Program Report: 3 In 1 Anion Bed Operating Pattern For Water Efficiency And Water Pollution Loads Improvement

In Tuban Regency, East Java, Indonesia, PT PLN Nusantara Power Unit Tanjung Awar-Awar Power Plant was built. There are two 350 MW coal-fired plants in operation. This project was built based on Presidential Regulation of the Republic of Indonesia No 71 of 2006 dated July 5, 2006 concerning assignment to PT PLN. The company is committed to the environment. They hire a highly skilled team of technicians and engineers to run water treatment plants (WTP). The PT PLN Nusantara Power Unit Tanjung Awar-Awar was able to solve many problems that were caused by the WTP by analyzing data and observing actual conditions. Specially to address concerns such as efficiency, safety, and saving money. A challenge of WTP operation is the limited ability of ion exchange resin (Anion) to remove impure ions from raw water. Hence, PLN introduced an innovative program called "THE IMPLEMENTATION OF 3 IN 1 ANION OPERATION PATTERN". We developed this program because anion beds need to be replaced every so often. The program reduces anion bed component replacement frequency. Due to the WTP's two anion beds, this operating method is possible. The first three days of operation are spent using Anion Bed-A, while Anion Bed-B remains on standby. We're contributing to 1) the anion bed replacement has been cut from once a month to once every three months, 2) significant reductions in waste water pollution load in 2022 of TSS=0,000624 tonnes and CL=0.00000714 tonnes.

Planning maintenance when resources are limited: a study of periodic opportunistic replacement

Abstract Accepted by: M. Zied Babai We study an aged-based replacement policy with two control limits. The first triggers opportunistic replacement and the second triggers a guaranteed replacement. The policy is novel because: the instances for component replacement are restricted to instances of time, which we call slots, that arise periodically; and a slot provides an opportunity for replacement with a particular probability. The policy models contexts in which maintenance is periodic, and resources are limited or execution of maintenance is not guaranteed. The policy is important for practice because it is simple and reflects the common reality of time-based maintenance planning. Long-run cost per unit time and average availability are calculated in a renewal-reward framework. Numerical study indicates that, if opportunities are rare, guaranteed replacement is beneficial and opportunities should be taken early in the life of a system. Using the policy, a maintainer can evaluate the cost–benefit of investing more resources to reduce the time between slots. Specific analysis and policy comparisons can be carried out using a web-application developed by the authors.

Rehabilitative outcomes with preparatory suction prostheses following traumatic Gritti-Stokes amputation: A case series.

Gritti-Stokes amputation (GSA) is a knee disarticulation variant, where the femur is transected at the level of the epicondyle and the patella is fixated to the distal end. GSA results in a long residual limb with little postoperative swelling and less potential for muscular atrophy, so stable limb volume may allow the use of seal-in suction for suspension for preparatory prostheses. The purpose of this case series was to report on the efficacy of seal-in suction preparatory prostheses for 2 adults with traumatic GSA. Between October and December of 2021, 2 participants with unilateral traumatic Gritti-Stokes amputation, who had received seal-in suction suspension for their preparatory prostheses, were recruited. Information was extracted from medical charts regarding prosthetic care and mobility at preparatory and definitive prosthesis evaluation, and participants underwent standardized measurement of their residual limb and prosthesis. Duration of preparatory prosthesis use was >6 months; neither participant reported loss of suspension nor significant complications with socket fit. Participant 1 required socket replacement because of residual limb pain secondary to osteophyte formation, and Participant 2 required component replacement because of weight gain. At definitive prosthesis evaluations, both participants were unlimited community ambulators; both successfully returned to work before provision of their definitive prostheses. Results indicate that seal-in suction suspension may be viable for preparatory prostheses among adults with traumatic GSA, but knee center height discrepancies persist. GSA may yield highly functional outcomes for adults with traumatic amputation. Further research is required to substantiate these findings.