Temporary Equipment Research Articles

Passenger Route and Departure Time Guidance Under Disruptions in Oversaturated Urban Rail Transit Networks

The urban rail transit (URT) system attracts many commuters with its punctuality and convenience. However, it is vulnerable to disruptions caused by factors such as extreme weather and temporary equipment failures, which greatly affect passengers’ journeys and diminish the system’s service quality. In this study, we propose targeted travel guidance for passengers at different space–time locations by devising passenger rescheduling strategies during disruptions. This guidance not only offers insights into route changes but also provides practical recommendations for delaying departure times when required. We present a novel three-feature four-group passenger classification principle, integrating temporal, spatial, and spatiotemporal features to classify passengers in disrupted URT networks. This approach results in the creation of four distinct solution spaces based on passenger groups. A mixed integer programming model is built based on individual level considering the first-in-first-out rule in oversaturated networks. In addition, we present a two-stage solution approach for handling the complex issues in large-scale networks. Experimental results from both small-scale artificial networks and the real-world Beijing URT network validate the efficacy of our proposed passenger rescheduling strategies in mitigating disruptions. Specifically, when compared to scenarios with no travel guidance during disruptions, our strategies achieve a substantial reduction in total passenger travel times by 29.7% and 50.9%, respectively, underscoring the effectiveness in managing unexpected disruptions.

사무직, 기능직, 단순노무직 건설업 근로자의 유해요인노출시간 및 건강문제 비교

Objective: This study aims to compare the working conditions, exposure time to hazard factors, and health-related issues among office, craft, and elementary construction workers.BRBackground: Construction workers are exposed to hazard factors such as limited space, temporary equipment, high temperatures, dark lighting, and harmful substances due to the changing and complex work environment.BRMethod: This study analyzed data from the 6th Korean Working Conditions Survey (KWCS) in 2022. A total of 1,743 construction workers from different occupations including 883 clerks, 764 craft workers, and 146 elementary workers were analyzed for the general characteristics of their working environment, exposure time to hazard factors, and health-related problems according to occupation.BRResults: The results indicated that the characteristics of on-site craft and elementary workers are different from those of clerks. The on-site workers reported the highest exposure to ergonomic risk factors, and their exposure to physical risk factors was also significant. They reported being exposed to repetitive motions and standing postures for more than four hours a day. In addition, they reported being exposed to awkward postures and vibrations for more than three hours and being exposed to handling heavy materials, noise, high/low temperatures, and fumes and dust for more than two hours. As a result, the incidence of musculoskeletal pain was the highest in the upper limbs while the lower back and lower limbs follow. Furthermore, there were many workers who complained of overall fatigue and depression based on the WHO-5 index.BRConclusion: The incidence of musculoskeletal pains and complaints of overall fatigue and depression suggests the need for comprehensive support to improve the working environment and to prevent psychological health-related hazardous factors for construction workers.BRApplication: This study provides basic data on the hazardous factors and healthrelated issues of on-site construction workers, which can be used as a basis for developing comprehensive measures to improve the working environment and psychological health-related hazardous factors.

An Optimized Proportional Integral Derivative (PID) based Power System Stabilizer (PSS) for Damping of Active Power Oscillations

Rising load demand and possibilities of short interruptions either due to temporary faults or equipment switching may lead to a transient instability in terms of growing oscillations and eventually result into cascaded outages if not being damped properly and timely. To damp out such oscillations, the power system stabilizers (PSS) are invariably being installed to regulate the excitation of synchronous generators. In this research, a comparative analysis among the two design variants of PSS i.e., Lead Lag and PID is performed by comparing the overshoot and settling time of generator active power after distrubance, to observe the effect of each on the system characteristics and nominal conditions. The results obtained show a better performance of PID based PSS having better overshoot response and reduced settling time for symmetrical as well as unsymmetrical faults.

Joint tank container demurrage policy and flow optimisation using a progressive hedging algorithm with expanded time-space network

A key feature of the tank container (TC) operating industry is that customers overhold TCs to provide temporary storage equipment for their contents rather than provide their own storage facilities. TC operators charge a very profitable fee (demurrage charge) for this service making it an attractive business proposition, but it can be detrimental to holistic network flows and fleet sizing. This paper addresses the problem of jointly optimising TC demurrage policy and TC flow, in the face of uncertain TC maintenance times, to maximise profits. A progressive hedging algorithm with expanded time-space network (PHA-ETSN) is designed to tackle this tactical level optimisation problem as other established techniques struggle with this optimisation in terms of computational time and memory requirements. Experiments are performed to illustrate how the optimisation tool can be used to investigate how demurrage policy affects different operational costs and TC hire revenue and thereby profit. These experiments demonstrate how the optimisation tool can be used by managers not only to optimise demurrage policy but also to explore and to understand more deeply the costs and profits in their operations.

Analysis of Major Temporary Electrical Equipment Consumption and Usage Patterns in Educational Buildings: Case Study

The energy use patterns of electrical appliances are more difficult to predict than energy use for heating, ventilation, and air-conditioning (HVAC) and lighting, as: (1) there are large varieties of electrical equipment (e.g., appliances, vending machines, etc.) in buildings and each serves a different function; thus, their energy consumption patterns are difficult to predict; (2) electrical appliances are scattered across buildings, most are not permanently fixed to a location, and they consume much energy. Appliances are also not centrally controlled, such as HVAC and lighting. Thus, energy consumption patterns are more difficult to predict. In addition, electrical appliances consume significant amounts of energy to influence energy consumption volatility. This case study focuses on understanding the energy consumption patterns of electrical appliances in educational buildings. This research analyzes the electrical appliances and energy consumption data from institutional buildings and the factors that drive energy consumption. The analyses show that: (1) energy consumption patterns are dependent on building characteristics and use; (2) the number of appliances in a building influences the peak electricity consumption; (3) vending machines and fridges consume significant amounts of electricity; it has been proven (by minimum building energy loads) that buildings that have more vending machines have significantly higher minimum loads than no or fewer vending machines; and (4) the energy-saving potential from desktops and monitors rose to 60 kWh during lunchtime and 500 kWh at night.

Suggestion of Safety Certification Standards and Performance Evaluation Methods for Fabricated Mobile Scaffold in South Korea.

At construction sites, various types of temporary equipment and structures are used for safety and work efficiency. However, various temporary equipment-related accidents frequently occur for many reasons, including inappropriate installation, usage, and material and structural imperfections. A mobile scaffold is one of the most commonly used indoor temporary equipment for work in high places. In general, the main structural members of the mobile scaffold, such as the mainframes, horizontal members, braces, caster wheels, outriggers, and handrails, are installed on the construction site for this purpose. This means that the load-carrying capacity of the equipment can vary depending on the assembly details. In Korea, there are safety certification standards applied for frequently used temporary equipment, such as scaffolds and shoring. However, the standards concern the strength criteria for the member itself, rather than the global load-carrying capacity. Therefore, it is difficult to review whether the fabricated mobile scaffold has sufficient load-carrying capacity, or to confirm the structural safety considering the various uncertainties affecting the structural performance. In this study, rational safety certification standards and evaluation methods are suggested for fabricated mobile scaffolds. The suggested safety certification standards present structure-level criteria for checking the load-carrying capacity, horizontal stiffness of the structure, and overturning risk. It is expected that the structural performance for safety can be directly checked based on the suggested safety certification standards and performance evaluation methods during the safety certification stage.

Internet of things application for smart construction assets

Internet of things (IoT) devices allow data to be communicated efficiently using low power to a central server to report location, movement, temperature and environmental attributes. With improvements in device connectivity distance, improved link margins, reductions in IoT hardware platform costs and the availability of higher-capacity batteries, non-powered temporary construction equipment (e.g. concrete barriers) can become smart and trackable. For this study, a long-range (LoRa) sensor platform is connected through an IoT low-power wide-area network (LPWAN) to test the feasibility of tracking construction equipment related to transportation. The signal strength relative to distance is analysed along with the radio-frequency signal attenuation of the signal strength through construction materials. The preliminary results show that a commercially available LoRa sensor with an omnidirectional antenna operating on an LPWAN can transmit up to 1310 m at grade. It is expected that these types of sensor platforms can be applied to other types of non-powered construction equipment to introduce smart functionalities. From the study, it was determined that it is feasible to deploy a LoRa-based sensor network to track non-powered temporary construction equipment. The study also demonstrated that a cost-effective poly(vinyl chloride) housing could be effective after 300 freeze–thaw cycles.

Development of a procedure for analysis and design of access scaffold

AbstractThe European design code for temporary work equipment and especially for scaffolding, NF EN 12811‐1, defines the cross‐section non‐linear plastic resistance criterion, which requires including initial imperfections in the global analysis of the structure. At the same time, the European design code for steel structures, Eurocode 3 Part 1‐1, establishes the buckling resistance criteria enabling to free ourselves from the modeling of initial imperfections. However, they do not offer the opportunity to exploit the non‐linear plastic resistance capacities of the cross‐section. Moreover, these buckling resistance criteria are often based on hypotheses and lead to inconsistencies between the verification with cross‐section criteria or with buckling criteria. The objective is to develop a procedure for analysis and design of access scaffold. The developed approach takes into account the interaction between section resistance and instability phenomena, and includes the influence of initial imperfections, such as initial defect of aplomb, lack of straightness and residual stresses. As far as possible, these effects will be decoupled. In order to verify the efficiency of the proposed procedure, several examples of typical scaffolding structures have been studied and the results prove the performance of proposed formulations.

Experimental Investigations on Ultimate Behavior of Fabricated Mobile Scaffolds

A fabricated mobile scaffold has various components, including vertical members, horizontal members, braces, work plates, and castor wheels. In Korea, the structural performance of each member must be validated based on member-level structural safety criteria; this means that rigorous evaluation methods are required to secure the system-level structural safety of the fabricated mobile scaffold. To suggest rational system-level structural safety criteria and effective evaluation methods, the characteristics of the structural behaviors of the assembled structure must be investigated first. Unlike other temporary equipment, it is a product that requires convenience of use and ease of movement. Therefore, to secure the safety and usability of the structure, it is necessary to evaluate the ultimate behavior of a mobile scaffold fabricated with various material and structural types. In an experimental study, the ultimate mode and load-bearing capacity were investigated, and the appropriateness of the required performance of the mobile scaffold was reviewed. Three types of experimental test models with different materials (steel and aluminum) and stories (single-story and three-story erection) were selected and examined for vertical loads. Based on the experimental results, the ultimate behavior characteristics of the fabricated mobile scaffold were analyzed, and the ultimate load was identified.

Opportunistic Network Algorithms for Internet Traffic Offloading in Music Festival Scenarios.

Constant Internet connectivity has become a necessity in our lives. Hence, music festival organizers allocate part of their budget for temporary Wi-Fi equipment in order to sustain the high network traffic generated in such a small geographical area, but this naturally leads to high costs that need to be decreased. Thus, in this paper, we propose a solution that can help offload some of that traffic to an opportunistic network created with the attendees’ smartphones, therefore minimizing the costs of the temporary network infrastructure. Using a music festival-based mobility model that we propose and analyze, we introduce two routing algorithms which can enable end-to-end message delivery between participants. The key factors for high performance are social metrics and limiting the number of message copies at any given time. We show that the proposed solutions are able to offer high delivery rates and low delivery delays for various scenarios at a music festival.

Validity Estimation and Improvement Scheme of Safety Certification System for Temporary Equipment and Materials in South Korea

In this study, safety certification system of temporary equipment and materials established in domestic and foreign countries are compared and how to improve it and how to secure the safety are suggested.

Mixed integer programming for dynamic tower crane and storage area optimization on construction sites

Construction site layout planning, the arrangement of temporary facilities and equipment on site, is a fundamental part of construction preparation. In construction, the operation of tower cranes has a great impact on construction process execution and preparation costs. Therefore, tower cranes should be chosen and placed such that they enable smooth construction processes at minimal cost. Since the majority of loads on site are transported either from or to a storage area, the transport routes taken between tower cranes and storage areas have a high impact. This paper presents a mathematical model that computes cost-optimal positions for both tower cranes and storage areas. The model consists of two linked mixed integer programs, allowing for the detailed quality assessment of the obtained solutions. Time dependency is considered by subdividing the construction process into several construction phases. Conditions on site and construction elements can be retrieved from a building information model. Particular advantages of our approach include the close approximation of complex shapes via convex hulls. Available positions on site are represented by a fine grid and calculated during runtime, which allows for freer placement instead of restricting to a fixed number of possible locations given as input. Using mixed integer programming offers tremendous modeling possibilities and a rigorous quality guarantee for the obtained solutions. In contrast to existing heuristic approaches, the returned solutions are provably optimal up to the chosen optimality gap. A case study is provided to demonstrate the practical applicability of the proposed model.

Minimizing equipment shutdowns in oil and gas campaign maintenance

This paper considers the problem of scheduling periodic maintenance items for oil and gas plants. Each maintenance item involves various maintenance tasks and may require temporary equipment shutdowns, which are costly and highly disruptive to production. The aim is to minimise equipment shutdowns by grouping maintenance items with similar shutdown requirements into short-term maintenance operations called campaigns. Real plants can involve tens of thousands of maintenance items and thus manually scheduling the campaigns is an extreme challenge. In this paper, we develop a mixed-integer linear programming model for optimally allocating maintenance items to campaigns so that total shutdown cost is minimised. The model incorporates constraints on maintenance deadlines, campaign times, maintenance item suppression and labour hours per campaign. We solve the model for realistic scenarios involving data for Karratha Gas Plant in Western Australia, which is the main processing plant for the massive North West Shelf oil and gas project.

The sustainable development of coal mines by new cutting roof technology.

China consumes more than 3.6 billion tons of coal every year. In the meanwhile, coal accounts for over 60% of the energy consumption sector. Therefore, the sustainable development of coal mines is a problem that needed to be solved by the Chinese government. During the coal resources recovery process, the protective coal pillars between the adjacent working faces lead to a vast waste of coal resources. In order to mitigate the resource-wasting issue, a new technology of roof cutting with chain arm retaining roadway was put forward in this paper. First, the procedures of retaining roadway, roof-cutting parameters and the damage ranges of roadway surrounding rock induced by roof cutting with chain arm were analysed. Then, the working resistance of the temporary support equipment is given when using the new technology to retain the roadway. Next, the roof-cutting height, the temporary support equipment selection, working resistance of portal support and support parameters of the bolt and anchor cables were optimized based on the numerical calculation. The industrial experiment of retaining roadway by roof cutting with chain arm was carried out in a working face. The surrounding rock damage was lowered and controlled with the application of chain arm roof-cutting technology. Also, it was found that the variation range of the uniaxial compressive strength was only 5%, resulting in the roof damage range of 82 mm. The new technology has proved a potentially wide application in the coal mining industry with prosperous economic and safety improvement.

Operation of Battery Storage as a Temporary Equipment During Grid Reinforcement Caused by Electric Vehicles

Electric vehicle charging stresses distribution grids significantly with high penetrations of electric vehicles. This will lead to grid reinforcement works in several distribution grids. Battery storage is a possible solution to bypass times of grid reinforcement due to electric vehicle charging. In this paper, different operation strategies for such a battery storage are tested at first in simulations. The main difference between the strategies is the necessary input data. Following the simulations, selected strategies are tested in reality in the project ”Netzlabor E-Mobility-Allee”. It is proved that battery storage is a functioning possibility to bypass times of grid reinforcement.

MODERN MEANS OF TRANSPORT IMMOBILIZATION AS A METHOD OF ELIMINATING LIFE-THREATENING CONSEQUENCES AND PREVENTION OF SEVERE COMPLICATIONS IN INJURIES OF THE PELVIS AND EXTREMITIES

Analysis of application of temporary immobilization equipment in case of injuries of lower extremities and pelvis. Considered the main characteristics temporary immobilization equipment in case of injuries of lower extremities and pelvis and features of their use in the provision of specialized emergency medical care.

Border Alert System for Fisherman using RSSI

Increasing strains across the ocean fringes caused extensive destruction between two countries. Anglers from any nation are being snatched for the perimeter by the service force, which is accidental to the bulk of the circumstances. Following the domain of watercraft victimization RSSI, the feasible generation of this system works, provides strong transcription path and temporary arrangement equipment for total shoppers on an identical substructure all told climate, day associate degree night on or near Earth and initiate an exhortation signal once the city district is taken closer or passed.Withal, in further organizing, the understanding of RSSI is transferred to the bone fence and thus the speed of the engine of the watercraft takes off the engine by managing the fuel supply. Later on, sentinels on the coast will profit and provide the anglers with additional profit and not travel near the district of the town.

Structural health monitoring of the Ferrara University before and after the 2012 Emilia (Italy) earthquake, and after the damage repairs

In this article, a framework of building monitoring is developed and transient and permanent variations of the fundamental period of vibration caused by both damage and repair interventions are investigated. The buildings of the University of Ferrara (Emilia-Romagna Region, Northern Italy), struck by the 2012 Emilia seismic sequence, were monitored using both temporary and permanent equipment: the first one to perform ambient vibration tests and the second one to implement permanent real-time monitoring for earthquake recording. Three on-demand ambient vibration tests were performed at each floor of the buildings: the first dataset was acquired a few months before the mainshock occurred on 20 May 2012 (ML = 5.9, 6.8 km depth and 30 km epicentral distance); the second was acquired right after the end of the sequence, when the building showed slight damage (degree 1 according to the European Macroseismic Scale 98); finally, the third dataset was acquired in 2016 after the repair intervention. The data analysis clearly documented the permanent drop of the first vibration frequency as a symptom of the damage and its partial recovery that followed the repairs. The permanent real-time monitoring system, despite the fact that it was implemented using low-cost sensors, provided an insight into the intra-event frequency variation, allowing in turn a preliminary damage assessment.

The High-risk Groups According to the Trends and Characteristics of Fatal Occupational Injuries in Korean Workers Aged 50 Years and Above

BackgroundDue to an increasing number of workers aged 50 years and above, the number of those employed is also on the rise, and those workers aged 50 and over has exceeded 50% of the total fatal occupational injuries. Therefore, it is necessary to implement the selection and concentration by identifying the characteristics of high-risk groups necessary for an effective prevention against and reduction of fatal occupational injuries.MethodsThis study analyzed the characteristics of high-risk groups and the occupational injury fatality rate per 10,000 workers among the workers aged 50 and over through a multi-dimensional analysis by sex, employment status of workers, industry and occupation by targeting 4,079 persons who died in fatal occupational injuries from January 2007 to December 12.ResultsThe share of the workers aged 50 years and above is increasing every year in the total fatal occupational injuries occurrence, and the high-risk groups include 'male workers' by sex, ‘daily workers’ by worker’s status, ‘craft and related-trades workers’ by occupation, and ‘mining’ by industry.ConclusionThe most frequent causal objects of fatal occupational injuries of the workers aged 50 years and above are found out to be ‘installment and dismantlement of temporary equipment and material on work platforms including scaffold’ in the construction industry and ‘mobile crane, conveyor belt and fork lifts’ in the manufacturing industry.

Full scale optimisation of sludge dewatering and phosphate removal at Harnaschpolder wwtp (The Hague, NL)

Abstract At Harnaschpolder wwtp phosphate removal from wastewater and sludge dewatering is optimised by dosing magnesium hydroxide to digested sludge. To optimise sludge dewatering and phosphate removal, a full-scale test has been executed since August 2015 using temporary equipment. In this test magnesium hydroxide is added to the digested sludge buffer. Significant positive results are achieved. An excellent quality of the reject water is obtained, through which the phosphorus load in this reject water returned to head of works is negligible. This decrease in combination with other optimisations are beneficial for the biological phosphorus removal process. In 2016 the phosphorus effluent quality remained constant, while 42% less iron chloride was added to meet the legal phosphorus effluent quality requirements (yearly moving average Ptotal < 1.0 mg P/l). The polymer usage decreased by 25% and the year average dry matter content of the dewatered sludge increased from 22% in 2014 to 24% in 2016. Struvite scaling or blockage is avoided in piping, pumps or dewatering equipment, through optimised control of dosage of magnesium hydroxide. The full-scale test results prove that the addition of magnesium hydroxide to digested sludge leads to a significant cost reduction and major environmental benefits. In 2017 a permanent installation will be realised. The magnesium hydroxide dosage will be further optimised based on lessons learnt. Also an improved operation control of sludge dewatering is possible through additional in-line measurements for dry solids content of dewatered sludge. It is therefore expected that results will further improve concerning the use of iron chloride and polymers, dry solids content of dewatered sludge and phosphate effluent quality. Through this optimisation, the operating costs1 of Harnaschpolder wwtp are reduced by over 4%. The return on investment is estimated at 1.5 years.