Journal of Applied Engineering Science

ROBUSTNESS OF PRESTRESSED REINFORCED CONCRETE STRUCTURES UNDER SPECIAL IMPACTS

Natalia Fedorova, Tatiana Iliushchenko — Thu, 12 Sep 2024 00:00:00 +0200

The purpose of the study was to develop the principles of the theory of robustness of reinforced concrete structural systems of buildings and structures with prestressed elements and methods of protecting them from progressive collapse under special impacts. To achieve this, the article presents the results of studies of monolithic reinforced concrete frames of multi-storey buildings and reinforced concrete frames, with prestressed elements in transcendent states caused by special effects, are given in the article. The current state of the problem of robustness of building frames under special impacts is considered. A method for calculating the reinforced concrete frame of a multi-storey building with prestressed elements has been developed and its static-dynamic deformation has been studied to determine the robustness parameter. The parameters of deformation and destruction of prestressed reinforced concrete multi-story frame frames of buildings under design and beyond design impacts are experimentally determined. The results of the experimental study of frame structures are compared with the results of studies of similar structures without prestressing. The obtained results of the study can be used in the development of methods for protecting the frames of multi-storey buildings from progressive collapse.

APPLICABILITY OF BITUMINOUS-BASED INHIBITOR AS CORROSION PREVENTION METHOD IN REINFORCED CONCRETE

Pinta Astuti — Mon, 24 Jun 2024 00:00:00 +0200

Corrosion is the most common cause of structural and material degradation in reinforced concrete (RC) constructions. A well-constructed structure protects the embedded steel bar from chloride ions both physically and chemically, which is particularly important for constructions exposed to seawater. Given the significant economic losses caused by corrosion, suitable measures to reduce corrosion in concrete are required. In this study, three-layer of bituminous-based inhibitor was applied to the surface of two steel bars embedded (steel coating) in mortar cement with 3 cm and 5 cm of concrete cover. Portland composite cement (PCC) and Portland pozzolan cement (PPC) was used as a binder material of mortar cement. The cubical mortar cement specimens were fabricated, and exposed to three conditions (e.g., wet condition, dry condition, and dry-wet cycle) until 60 days after 28 days of immersed water curing. The results demonstrated that corrosion prevention employing steel coating techniques by using bituminous-based inhibitor gives superior protection as seen by a higher positive corrosion potential value when compared to non-coating specimens, implying that the coating method may be used to prevent corrosion. This is because the coating process by using bituminous-based inhibitor may prevent ions from entering the reinforcing steel. In all exposure circumstances and with all preventive procedures, a concrete cover with a thickness of 5 cm has a lower corrosion risk, as shown by a higher corrosion potential value, than a concrete cover with a thickness of 3 cm. The larger the thickness of the concrete cover, the more the surrounding ecosystem is protected. The utilization of PPC as binder in concrete maintained the stable corrosion potential value when the coating method applied.

INTELLIGENT RADIOACTIVE WASTE INACTIVATION AUTOMATION SYSTEM

Apostolos Tsagaris, Margarita Taousani , Georgios Mylonas — Sun, 18 Aug 2024 00:00:00 +0200

The paper deals with the implementation of an intelligent automation system that ensures the smooth operation of a radioactive waste inactivation system as well as the SCADA system responsible for monitoring the entire automation system. It includes the inspection of five radioactive waste management tanks and a central radioactive waste collection pit of a Nuclear Medicine laboratory. The purpose was to create an intelligent automation system with PLC with the possibility of the future expansion of the reservoirs after an increase in hospitalized patients. Object-oriented programming was used with modern control code development techniques, but also visualization of all necessary information. The states tested for system operation are Collection, Treatment, and Wastewater Waiting. Each of the 5 collection tanks has a level sensor, safety float, sewage agitation system, sewage inlet and outlet valves, wash valve, and sampling valve. The system has a central valve that directs wastewater from patient rooms receiving radioactive iodine treatment either to the quench tank system via a central sump or to the central sewer system. Active sewage is collected in the central well and pumped to the collection tank. The central well has a level sensor to activate the pumps and a safety float.

CYCLIC BEHAVIOR AND CRITICAL PART OF ECCENTRIC BRACED FRAMES WITH VERTICAL LINKS

Lilya Susanti, Ming Narto Wijaya, I Gde Eka Wiranatha, Abdourahim Jallow — Mon, 29 Jul 2024 00:00:00 +0200

A vertical shear link-equipped reinforced concrete eccentric braced frame (RC-EBF) exhibits a unique behavior that has yet to receive much research. The vertical shear link is located separately from the main beam, so it does not interfere with its performance. Moreover, it gives structural retrofitting flexibility. To comprehend the structural strength of EBF compared to Concentric Braced Frames (CBF), the current work explored the cyclic deformation history of RC-EBF type Y (vertical shear links). It also sought to identify the critical frame components contributing to structural failure. The investigation involves nine specimens comprising CBF and EBF with 15 cm and 25 cm vertical linkages. Cyclic load-displacement histories revealed that the CBF configuration is the stiffest and most reliable one. The CBF structure exhibits equal deformation at higher cyclic loads than the EBF. Shear stress is the critical factor contributing to the structure's collapse, as demonstrated by the diagonal main crack in the current EBF samples.

NUMERICAL ANALYSIS OF AN AUTOMOTIVE CAGE USED IN THE PERUVIAN MINing SECTOR

Mon, 19 Aug 2024 00:00:00 +0200

A comparative analysis was conducted between the two structural formats employed in crafting internal roll cages in the Peruvian domestic market (Tubular and Laminar). The aim was to discern the protective effectiveness of each design. The examined cage design pertains to the most prevalent light utility vehicle used within the national mining sector. The computational analysis sought to derive Von Mises forces, resultant deformations, safety factors, and displacement along the applied force direction. This simulation was executed through finite element analysis, incorporating regulations sourced from the International Automobile Federation (FIA) and the Federal Motor Vehicle Safety Standards (FMVSS), which were adapted via analysis of Roll Over Protective Structures (ROPS). The results demonstrate a substantial safety factor in the laminar cage and a lesser concentration of Von Mises stresses in the tubular cage. Nonetheless, both structures experience significant deformations when subjected to lateral loads and at their respective joints. As a conclusion, it can be deduced that both structural configurations adopted in the crafting of interior roll cages adhere to specified standards. Notably, the laminar cage presents aesthetic and mechanical advantages. How-ever, the necessity for experimental testing to comprehend the structure's dynamic behaviour is underscored.

MECHANICAL ANALYSIS ON TEST SAMPLES MADE IN CONCRETE REINFORCED WITH STEEL FIBERS

Sun, 18 Aug 2024 00:00:00 +0200

Steel fibers have been used for improving the behavior of structural concrete elements for a long time ago. This paper shows the main results from the flexural test of steel fiber reinforced concrete beams, that is to say, flexural strength and toughness. The results were compared with those from the flexural test of reinforced concrete beams with steel bars and plain concrete beams. Steel fiber did not increase the flexural strength and toughness of beams when compare with reinforced beams with steel bars but it does improve the behavior of steel fiber reinforced concrete beams for failure control and gradual mechanics which allows caution about upcoming collapse.

THE EFFECT OF FUEL PREHEATING ON THE PERFORMANCE OF USED OIL FUEL STOVES

Sudarno Sudarno, Fadelan Fadelan, Wisnu Aji Setyatinika, Yoyok Winardi — Tue, 30 Jul 2024 00:00:00 +0200

This research explores the utilization of used oil as an alternative fuel and investigates the impact of preheating on its performance in combustion chambers. The study employs an experimental approach to vary preheating methods, utilizing two models: a ring placed in the combustion chamber and a ring combined with a spiral between the inner and outer stove walls. A comparative analysis is conducted against conventional stoves. The investigation focuses on efficiency and flame temperature distribution. Results reveal that the stove incorporating the spiral-ring preheating model demonstrates the highest efficiency at 55.52%, marking a 9.76% increase over conventional stoves. Additionally, this model generates the largest average heat area and the highest temperatures, notably reaching 1077°C, with a broader area above 1000°C compared to other models. The preheating process aids in reducing fuel viscosity and enhancing evaporation, facilitating a more homogeneous air-fuel mixture, thereby promoting more complete combustion.

REVERSE ENGINEERING MODELING PROCESSING AND FABRICATION OF VORONOI PERFORATED ANKLE-FOOT ORTHOSIS

Sun, 04 Aug 2024 00:00:00 +0200

The ankle may not function optimally because of an ankle foot injury due to torn ligaments or foot drop, a post-stroke effect of hemiplegia. One treatment that can be done for sufferers of ankle foot injury and foot drop is using an ankle foot orthosis (AFO). Reverse engineering (RE) and additive manufacturing (AM) technologies can be utilized within the medical domain, specifically for producing prosthetic devices and orthoses that include optimal fit, lightweight characteristics, and cost-effectiveness. This study aims to create an optimized design for an ankle-foot orthosis by utilizing reverse engineering techniques, followed by an analysis of its performance using finite element simulation. The research process involved several key steps, namely 3D Scanning, CAD modeling, model analysis, and 3D printing. The findings of the model study after the implementation of Voronoi ventilation holes indicated that the highest equivalent stress observed in the model, with a shell element thickness of 1.4 mm, amounted to 21.12 MPa. This result represented an elevation of 11.74% compared to the model before introducing Voronoi ventilation holes. Nevertheless, there was a reduction in the model's mass by 20.3%, specifically from an initial weight of 400.86 grams to a final weight of 319.51 grams. On the contrary, despite a fall in the safety factor, it continues to be considered safe, with a value of 2.84.

COMPARISON OF THE IMPACT OF THE COVID-19 PANDEMIC AND TECHNOLOGICAL DEVELOPMENTS ON EMISSIONS OF CO2 IN THE AIR TRANSPORT

Marija Čubić, Adam Török — Fri, 13 Sep 2024 00:00:00 +0200

Air transport is a complex and intricate mode of transportation that has both benefits and consequences resulting from the operations of planes. Air travel offers the advantage of saving time during journeys or business visits, but it also has the disadvantage of contributing to carbon dioxide emissions caused by aircraft operations. These emissions present potential risks to both human health and the environment. In order to reduce the negative impacts, new technical advancements can be utilized to limit emissions and, consequently, the discharge of carbon dioxide. The COVID-19 epidemic caused an unprecedented situation where flights were temporarily suspended and aircraft were grounded, leading to a significant decrease in emissions from airline operations. This research utilizes graphical representations to clarify the main factors that lead to reduced carbon dioxide emissions. Moreover, it examines the effects of particular advancements in air transportation and assesses the impact of the pandemic on the overall decrease in emissions.

SIMULATION MODELING OF LOGGING HARVESTER MOVEMENTS DURING SELECTIVE LOGGING

Konstantin Rukomojnikov, Tatiana Sergeeva — Wed, 24 Jul 2024 00:00:00 +0200

The purpose of this research is to substantiate the mathematical regularities of the harvester operation, allowing for rapid technical calculations of labor costs with a sufficient level of reliability when performing various logging operations. The article describes the simulation model of harvester movement in the cutting area, created by the authors to analyze the operation of the harvester at various logging sites. Examples of visualization of the program and the results obtained with its use are given. Four-factor experimental plan was drawn up with varying factors at four levels. The results obtained during the simulation have been statistically processed. The analyzed elements of the cycle time are: the average time of pointing the manipulator at a tree, the average time of moving a fallen tree to the processing zone and the average time of moving the harvester between working positions per felled tree. The regression dependencies obtained as a result of the analysis are based on four indicators. Such indicators are: the total stock of wood per hectare, the share of the felled component of the stand, the amount of undergrowth (rowan, bird cherry, willow, etc.) in the cutting area, the average volume of the tree in the cutting area. The found patterns give the researcher a general idea of the effectiveness of the equipment in specific natural conditions of cutting areas. The use of the acquired knowledge in the analysis of harvester performance will improve the accuracy of planning the work of logging crews.

STUDY OF TECHNOLOGY FOR THE RELIABILITY AND SURVIVABILITY MODELLING OF ONBOARD CONTROL SYSTEM OF SMALL SPACECRAFT OPERATING IN COMPLEX MODES

Tue, 30 Jul 2024 00:00:00 +0200

The technology of system modeling of reliability and survivability of the onboard control system (OCS) of the spacecraft is presented in the study of various options for the activation of operating modes. The technology of spacecraft functioning based on the concept of digital twins currently takes a leading position. That’s concept allows you to create realistic virtual copies of spacecraft, to simulate not only the objects themselves, but also the processes of their design and operation in various conditions of a priori uncertainty. Such conditions, first of all, should include the destructive effects of an aggressive external environment (outer space) and the multi-mode nature (sequence and intensity of the modes involved) of the functioning of onboard spacecraft systems. The implementation of the requirements of multi-purpose and multi-mode control in these conditions is closely related to the study of the reliability and survivability of such objects from the standpoint of considering their structural construction. The proposed article discusses an approach to assessing the reliability and survivability of onboard systems of small spacecraft (SS), which is based on the concept of a parametric genome structure, taking into account the multi-mode operation in an aggregated form.

EFFECT OF GAS NITRIDING PARAMETERS ON THE MICRO-HARDNESS OF HIGH-SPEED STEEL-CUTTING TOOLS

Falah Mustafa Al-Saraireh, Shatha Suhymat — Tue, 30 Jul 2024 00:00:00 +0200

In this study, the nitriding parameters, such as nitriding time, nitrogen flow, and cooling type, were regularly modified to assess the effects of each on the microhardness of tools constructed of high-speed steel designed for commercial usage. The nitriding temperature was maintained at 670 °С for all of the tools. The tools were designed to measure microhardness. With a maximum value of 2000 HV at a time of 42 hours, direct nitriding with a nitrogen flow of 20 l/h and air cooling exhibits an apparent relationship between nitriding time and microhardness. The maximum microhardness value (1555.44 HV) was achieved by quenching after nitriding for 72 hours with a nitrogen flow rate of 20 l/h. The relationship between nitrogen flow and microhardness is semi-direct for direct nitriding at a nitriding duration of 30 hours and furnace cooling, with a maximum value of 1566.65 HV at a nitrogen flow of 110 l/h. The maximum microhardness was 2000 HV, with a 1.63% increase. The microstructure of the tools was improved by increasing the concentration of iron nitride in the ferrite cell, which means that the gas nitriding process increases the efficiency of cutting operations and reduces workpiece material surface roughness, based on the results of this study, it is advised to use high-purity nitrogen rather than ammonia. high-purity nitrogen gives better results than traditional nitriding using ammonia gas.

INFLUENCE OF EXHAUST FAN POSITION AND THE ADDITION OF SECONDARY EXHAUST FAN TO CONTROL INDOOR AIR POLLUTION (IAP) INSIDE A PARKING GARAGE

Pramadhony Pramadhony, Dewi Puspitasari, Muhammad Said, Kaprawi Sahim — Tue, 10 Sep 2024 00:00:00 +0200

Air pollution has significantly deteriorated air quality in many urban areas, leading to numerous health issues. This pollution is not confined to outdoor environments but also affects indoor spaces, such as parking garages in basements. One major concern is cold-start emissions from idling cars, which produce higher concentrations of pollutants compared to normal hot emissions. Internal Combustion Engine Vehicles (ICEVs) emit cold-start emissions during the first few minutes after ignition. To mitigate this impact, parking operators typically use exhaust fans to replace polluted air with fresh air. However, the design and placement of the exhaust fan should be optimized to ensure a healthy indoor environment and efficient energy use. This research examines the concentration of air pollutants in a parking garage with three idling cars, focusing on the effectiveness of an exhaust fan installed in two different positions: near the parking spaces and near the pathway. Additionally, the research evaluates the impact of the exhaust fan's position and the inclusion of a secondary exhaust fan on carbon monoxide (CO) concentration during cold-start emissions. The results indicate that the primary exhaust fan should be installed in Position A, as it provides better airflow distribution and effectively extracts air pollutants. Improper airflow distribution, observed when the exhaust fan is installed in Position B, results in some measurement points showing high CO concentrations, with the highest average concentration reaching 68.9 ppm. Furthermore, the addition of a secondary exhaust fan helps reduce the average CO concentration and shortens the duration of the cold-start emission effect.

IMPROVED ROAD PERFORMANCE THROUGH THE IMPLEMENTATION OF ROUTINE ROAD MAINTENANCE MANAGEMENT SYSTEM

Wed, 31 Jul 2024 00:00:00 +0200

Road infrastructure development is carried out to be able to serve the flow of goods and passengers smoothly, safely, and comfortably. Infrastructure maintenance is needed to keep roads always in good condition. The road infrastructure consumes a significant amount of budget, both for road maintenance and improvement. The Central Java Provincial Government, through the Public Works Service for Highways and Civil Works, has a prioritization sequence to maintain road conditions to facilitate smooth, safe, and comfortable traffic. Continuous and sustainable maintenance of constructed roads is necessary to ensure their stability. Therefore, a large budget is required to carry out this maintenance. In 2023, the budget requirement for routine road maintenance amounted to IDR 441.246.000.000,00. However, the actual budget realization for 2023 was only IDR 125.686.108.000,00, fulfilling just 28,48% of the calculation model using from using analysis for Planning, Programming, and Budgeting (P/KRMS analysis) application. Analysis results indicate that the budget realization for routine road maintenance in 2023 did not meet the requirement to maintain a stable road surface, as evidenced by a 1,61% decrease in road surface condition from 2022. The Central Java Provincial Public Works Service for Highways and Civil Works faces this challenge by maximizing the involvement of the Community Group for Highways Development (Mas BIMA) in expediting the handling process.

RESEARCH OF WEAR AND INCREASING WEAR RESISTANCE OF THE WORKING PART OF BUSBAR PUNCHING TOOLS BY SURFACING METHOD

Sun, 18 Aug 2024 00:00:00 +0200

This article aims to establish the cause of wear and select a surfacing method to increase the wear resistance of the working part of the busbar punching tool. A study was carried out on existing methods for increasing the wear resistance of working surfaces of parts and tools operating under heavily loaded thermodynamic conditions, as well as under high contact and impact loads. As a result of the data analysis, the ESAB OK Tubrodur 35GM surfacing wire and the mechanized surfacing method using a protective gas environment were selected for surfacing the working part of the busbar punching tool. An experiment was planned to determine the number and parameters of experiments that will allow achieving the required level of accuracy to obtain the necessary information about the object of study. Calculations made during the experiment's planning resulted in a multiple regression equation that determines the dependence of the deposited layer's hardness on the current strength, welding voltage, and the speed of movement of the welding torch. The optimal operating parameters for surfacing samples in shielding gases were determined using the MATLAB software package. The research, the results of which are presented in this article, is funded by the Committee on Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan (grant № AP19578884 "Increasing wear resistance and improving the design of the tool of the busbar punching machine").

LONGITUDINAL VIBRATION ANALYSIS OF STRAIN GRADIENT ELASTIC BAR WITH VARIOUS BOUNDARY CONDITIONS

Vlasios Dimosthenis — Tue, 03 Sep 2024 00:00:00 +0200

In this paper, strain gradient elasticity (GradEla) is employed to investigate bar's longitudinal free vibration (LFV) behavior with several boundary conditions (BCs). The governing differential equation of motion for the bar is derived using Hamilton's principle. Various combinations of clamped, free, attached mass and/or spring BCs are used to solve it analytically. Notably, many of these solutions are the first in the literature for the gradient elastic bars. The effect of the internal length parameter, the modes, the attachments, the BCs, and the length of the bar is identified and assessed. It is concluded that the GradEla bar shows size-dependent and stiffer mechanical behavior compared with the classical one. Also, the presence of mass mainly decreases the longitudinal frequencies (LF) of bars, while the presence of the spring increases them. In addition, GradEla is applied to model a literature experiment demonstrating its applicability in real problems. Presenting these novel solutions and showcasing their effectiveness through experimental validation contributes to the advancement of understanding the use of GradEla theory in a wide range of longitudinal vibration (LV) problems of structural mechanics.

OPTIMIZING CONSTRUCTION PROJECT LIFESPAN VALUE USING TOTAL QUALITY MANAGEMENT PRINCIPLES

Ramy El-Messiery, Emad Elsherbiny, Tarek Nasr Eldin — Tue, 03 Sep 2024 00:00:00 +0200

An effective strategy aligning costs and quality is pivotal for augmenting project value in the construction industry. This study develops and applies a model to evaluate the impact of Total Quality Management (TQM) principles on Egyptian construction projects. Objectives include identifying key TQM principles, quantifying their value, and validating outcomes through a case study. Methodologically, a TQM evaluation model, utilizing the Relative Importance Index (RII) method and validated via Cronbach’s alpha, is formulated. A value formula estimates the financial impact of top TQM principles compared to construction project life cycle costs. Applied to a 2023 Egyptian construction project case study, the formula demonstrates cost savings surpassing the required investment. Specifically, project value improved 2.77 times using the created Value Engineering Business Approach (VEBA) formula, translating to an estimated 12.8% reduction in total life cycle costs. This research advocates a data-driven approach to prioritize TQM principles, showcasing positive financial returns for firms and endorsing TQM as an effective framework for the Egyptian construction sector.

THE MODEL FOR INTEGRATING ROAD FUNCTION, ROAD STATUS, AND ROAD CLASS IN THE ROAD NETWORK SYSTEM

Herry Kurniawan, Latif Budi Suparma, Suryo Hapsoro Tri Utomo — Thu, 12 Sep 2024 00:00:00 +0200

The lack of synchronization between road categories in Indonesia, which includes road function, road status, road infrastructure class, and road load class, results in negative impacts on roads, including air pollution, traffic accidents, congestion, and road deterioration that occurs more rapidly than the planned road lifespan. Another consequence is that the lack of synchronization between logistics transport trips and road function and classifications can lead to violations of the maximum axle load limits for goods vehicles. The objective of this research is to establish an analytical correlation between the identification of road segments based on road function, road status, road load class, and road infrastructure class, as well as the impact variables. Additionally, the aim is to develop a model for determining road function, road status, road infrastructure class, and road load class, along with their impact variables. The primary areas studied in this research are the road networks in Lampung, DIY, East Java, South Kalimantan, West Papua, Maluku, and Southeast Sulawesi. The research employs two quantitative techniques: Importance Performance Analysis (IPA) and Structural Equation Modelling (SEM). Data and information have been gathered through questionnaire surveys, desk studies, and interviews, which confirm Law No. 2 of 2022 concerning Roads, which explains that road function are derived from road status, while road infrastructure class and road load class are also derived from road function. The findings reveal that how roads are classified by their function has a major effect on traffic outcomes. This emphasizes the importance of categorizing roads based on their intended use. Consequently, it is crucial for planners to focus on functional classifications when designing and managing road infrastructure to tackle traffic issues effectively.

REVIEW OF THE ADAPTIVE SWEDISH TRAFFIC CONFLICT TECHNIQUE: APPLICATIONS AND IMPLICATIONS FOR ROAD TRAFFIC SAFETY

Wahyu Arif Pratama, Noor Mahmudah — Tue, 30 Jul 2024 00:00:00 +0200

The Swedish Traffic Conflicts Technique (STCT) is a systematic approach used to examine traffic conflicts, specifically emphasising the correlation between severe conflicts and accidents. It uses safety indicators such as average speed, post-encroachment time, deceleration rate, time to collision, and traffic flow size to evaluate the gravity of interactions between pedestrian and motorised vehicles. The development of the TCT has been significant, with studies highlighting the impact of speeding, inattentiveness, inadequate following distance, signal violations, drowsiness, excessive alcohol consumption, and reckless driving on road safety. The Adaptive STCT for road traffic safety is a significant area of research and development, aiming to enhance understanding of the global implementation and efficacy of the Adaptive Swedish TCT in enhancing road traffic safety. The STCT has been applied in various countries, including Sao Carlos, Nanjing, Ho Chi Minh City, and Qatar, and has shown significant development in identifying hazardous manoeuvres at urban intersections, facilitating the adoption of safer designs and efficient risk management measures. Nevertheless, research on the STCT's implementation on rural roads is limited; it highlights the need for further investigation and implementation in rural environments due to varying road safety issues.