Durability Of Alkali-Activated Concretes Under 5% Sulfuric Acid Environment,
2025
Department of Civil Engineering, Istanbul Gelisim University, Istanbul, Türkiye
Durability Of Alkali-Activated Concretes Under 5% Sulfuric Acid Environment, Celal Karabaş, Anıl Niş
Journal of Sustainable Construction Materials and Technologies
The investigation focused on the resistance to 5% sulfuric acid degradation of the alkali-activated concretes (AAC). The AAC was manufactured using a blended binder of 50% slag and 50% F-type fly ash. The AAC was activated using a blend of 14 M sodium hydroxide and sodium silicate, with a hydroxide-to-silicate ratio of 1/2,5. Six AAC were produced against a 5% sulfuric acid environment, varying the binder amounts (400–500–600 kg/m3) and activator-binder (A/B) ratios (0,45–0,55). The chemical resistance of AAC was evaluated by visual appearance, variation in weight and compressive strengths. The findings pointed out that more gypsum and higher weight …
Comprehensive Risk Assessment For Construction Site Managers In Kosovo: A Mixed-Method Approach,
2025
Faculty of Civil Engineering and Infrastructure, UBT-Higher Education Institution, 10000 Pristina, Republic of Kosovo
Comprehensive Risk Assessment For Construction Site Managers In Kosovo: A Mixed-Method Approach, Muhamet Ahmeti, Besian Sinani
Journal of Sustainable Construction Materials and Technologies
This study developed and validated a hybrid ISO 31000:2018 Kosovo-compliant risk assessment framework tailored for construction site managers operating within transitional economies. The research employed audits of 20 ISO-certified contractors in Pristina, Kosovo, along with field observations, interviews, and quantitative risk matrices. The findings indicate a critical concentration of risk, with 70% of firms classified as "High" or “Very High” risk. The most prevalent hazards identified were working at height without collective protection, unprotected electrical systems, and manual handling of heavy materials. Regression analysis revealed that firms with a designated safety champion achieved significantly lower risk scores, whereas those with …
Behaviour Of Internally Strengthening Hollow Stainless-Steel Hot-Rolled Circular Columns Filled With Crumb Rubber And Recycled Aggregate Concrete,
2025
Faculty of Engineering, Sohar University, 311 Sohar, Oman
Behaviour Of Internally Strengthening Hollow Stainless-Steel Hot-Rolled Circular Columns Filled With Crumb Rubber And Recycled Aggregate Concrete, Wadhah M. Tawfeeq, Mohammed M. Rasheed, Mithaq Kohees, Ahmed W. Al Zandd, Saif Al-Balushi, Hamed Al Abdul Salam
Journal of Sustainable Construction Materials and Technologies
Stainless-steel sections are increasingly being utilised in favour of their higher durability. Simultaneously, the use of recycled materials in concrete is aligned with the global concern to encourage sustainable and environmentally friendly construction. The paper examined the behaviour of stainless-steel columns filled with concrete with crumb rubber (CR) and recycled aggregate (RA). It analysed the effect of different percentages of CR (0, 15, and 30) and RA (0, 15, and 50) on the compressive strength of the concrete and the performance of the columns using stainless-steel hollow sections. 20 specimens were manufactured, 18 of which were cast with concrete containing …
Piezoelectric Concrete: A Smart Material Approach For Energy-Harvesting Structural Technologies,
2025
School of Civil Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia
Piezoelectric Concrete: A Smart Material Approach For Energy-Harvesting Structural Technologies, Dianah Mazlan, Vynotdni Rathinasamy, Naveen Kumar, Liu Chunpeng, Elango Elango
Journal of Sustainable Construction Materials and Technologies
The rapid growth of urban infrastructure demands innovative materials that not only support structural performance but also contribute to sustainability through energy harvesting. Piezoelectric concrete, which integrates ceramics, polymers, nanomaterials, and bio-based fillers into cementitious matrices, has emerged as a promising solution. This review systematically explores the fundamentals of piezoelectricity in concrete, highlighting how stress-induced electromechanical coupling enables both energy harvesting and structural health monitoring. The paper critically evaluates major material systems including PZT ceramics, PVDF polymers, hybrid nanocomposites, and emerging bio-based materials, alongside their integration strategies such as embedded and surface-mounted approaches. Applications across pavements, bridges, and smart buildings …
In-Situ Investigations Of Calcium-Magnesium-Aluminosilicates (Cmas) Infiltration Effects On Thermal Barrier Coatings Under Extreme Environments Replicating Jet Engines,
2025
Embry-Riddle Aeronautical University
In-Situ Investigations Of Calcium-Magnesium-Aluminosilicates (Cmas) Infiltration Effects On Thermal Barrier Coatings Under Extreme Environments Replicating Jet Engines, Zachary Stein
Doctoral Dissertations and Master's Theses
Calcium-magnesium-aluminosilicate (CMAS) particulates, such as sand or volcanic ash, are ingested by gas turbine jet engines during operation. When operating within high abundance regions, these particulates negatively interact and degrade the high temperature thermal barrier coatings (TBC) protecting underlying superalloy turbine blades vital to engine operation. These CMAS particulates melt within the engine and infiltrate into the ceramic coatings. In electron-beam physical vapor deposited (EB-PVD) TBCs, the CMAS within the intercolumnar gaps stiffens the coatings and causes thermomechanical induced high stress concentrations, risking crack formation. While molten, the CMAS thermochemically alters and destabilizes the coating, also risking coating failure. Premature, …
(R2122) Analysis Of Halo Orbits In The Elliptical R3bp With Mass Variation,
2025
AND College, University of Delhi, India
(R2122) Analysis Of Halo Orbits In The Elliptical R3bp With Mass Variation, Majhar Ali, Abdullah .
Applications and Applied Mathematics: An International Journal (AAM)
The elliptic restricted three-body problem investigates the motion behaviour of the variable mass infinitesimal body under the gravitational forces of the radiated oblate primary and dipole secondary. The equations of motion of the infinitesimal body are determined using Jeans law and Meshcherskii space time transformations. Using the Lindstedt-Poincaré method, we perform the solutions of the equations of motion. With the use of these solutions and the equations of motion, we numerically illustrate the time series, phase spaces, projections and the Halo orbits.
Powder Degradation Analysis In Reused Pure Tungsten For Electron Beam Melting (Ebm),
2025
University of Texas at El Paso
Powder Degradation Analysis In Reused Pure Tungsten For Electron Beam Melting (Ebm), Hernan Valenzuela
Open Access Theses & Dissertations
Additive manufacturing (AM) enables unparalleled design freedom and geometric complexity, driving its adoption in aerospace and medical fields. A major advantage of metal powder AM technologies, such as Electron Beam Melting (EBM), is its ability to reuse unused metal powder, reducing material waste and costs. However, reusing powder repeatedly alters its properties, affecting the final product. Despite its significance, research on powder degradation remains limited, primarily focusing on alloys like Ti-6Al-4V. This thesis investigates the degradation of pure tungsten powder reused over multiple Electron Beam Melting (EBM) cycles. A literature review revealed general powder-reuse mechanisms across additive manufacturing (AM) technologies …
Coupling Material Formulation Strategies To Tailor Piezoelectric Properties Of Ceramic Lattices,
2025
University of Texas at El Paso
Coupling Material Formulation Strategies To Tailor Piezoelectric Properties Of Ceramic Lattices, Amanda Lauren Borgaro
Open Access Theses & Dissertations
This thesis examines the material formulation and infiltration processes required to create interpenetrating ceramic composites with a particular focus on developing piezoelectric ceramic-epoxy lattice structures (PCELS). Following this, a high–solid loading barium titanite photopolymer resin (BT40) was developed to produce BTO scaffolds with controlled porosity suitable for metal infusion. The resin’s shear-thinning behavior and scattering-dominated curing response enabled the formation of stable, uniform ceramic structures whose pore networks directly influence infiltration behavior. Building on this foundation, a low-temperature Field’s Metal (FM) infiltration method was established using controlled thermal equilibration and the melting of pre-formed alloy rods. By maintaining the ceramic …
Development Of Oxide And Oxynitride Thin Films For Advanced Optical Applications,
2025
University of Texas at El Paso
Development Of Oxide And Oxynitride Thin Films For Advanced Optical Applications, Nathan Christopher Episcopo
Open Access Theses & Dissertations
To develop Ga2O3 and TiOₓNᵧ thin films for optical applications, the process–structure–properties relationship was investigated using a comprehensive set of characterization techniques to establish the atomic structure and composition of the films in relation to the deposition conditions. The results provide critical insights into how deposition parameters influence the atomic structure and composition during magnetron sputtering. Furthermore, the correlation between atomic structure and composition with the optical and electrical properties of the films was examined to determine how variations in these factors affect functional performance. Collectively, these findings offer the necessary information to target desirable optical properties for Ga2O3 and …
Microstructure Evolution During Annealing Of Cryogenically Processed Cantor High Entropy Alloy,
2025
University of Texas at El Paso
Microstructure Evolution During Annealing Of Cryogenically Processed Cantor High Entropy Alloy, Mynel Gomez
Open Access Theses & Dissertations
This work focuses on the annealing behavior of a cryogenically processed Cantor high entropy alloy over a wide temperature range of 500–800°C. Scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), and transmission electron microscopy (TEM) were employed to analyze the microstructural evolution, with particular emphasis on twinning. Hardness and grain size were measured to correlate these microstructural changes with mechanical properties. The cryogenically processed alloy exhibited a high density of twin bundles, resulting in an initial hardness of 338 HV. Upon annealing at 500 °C, 550 °C, and 600 °C, the material showed only a limited degree …
Decoupling Piezoelectric And Pyroelectric Effects In Anisotropic Polymer-Ceramic Lattices Produced Via Fused Filament Fabrication,
2025
University of Texas at El Paso
Decoupling Piezoelectric And Pyroelectric Effects In Anisotropic Polymer-Ceramic Lattices Produced Via Fused Filament Fabrication, Sofia Alexandra Perez
Open Access Theses & Dissertations
This thesis investigates how multi-material fused filament fabrication (FFF) can be used to engineer lattice structures that decouple piezoelectric and pyroelectric responses within a single polymer–ceramic composite. A hybrid ABS–BaTiO3/PLA lattice—referred to as the Hybrid PIZCAL—was designed to direct mechanical strain along the Z-axis while suppressing deformation in the transverse directions. After thermal poling, the lattice exhibited a 293% increase in Z-axis voltage sensitivity compared to a monolithic ABS–BaTiO3 cube and significantly reduced off-axis electromechanical output. Finite element simulations and directional compression testing confirmed that geometric anisotropy and material zoning produce strong, axis-selective piezoelectric behavior. The second part of this …
Spray Angle On The Performance Of Split-Type Ac Condenser Installed On Concrete Rooftop In Tropical Climate,
2025
Department of Mechanical Engineering, Tadulako University, Jl. Soekarno Hatta Km.9, Palu, 94118, Indonesia
Spray Angle On The Performance Of Split-Type Ac Condenser Installed On Concrete Rooftop In Tropical Climate, Kennedy Kennedy, I N Frenki Aryana, Basri Basri
Journal of Mechanical Engineering Science and Technology (JMEST)
This study investigated the influence of different water spray angles (0°, 15°, and 30°) on the thermal and energy performance of a split-type air-conditioning (AC) condenser installed on a concrete rooftop in a tropical climate. An experimental setup was designed to replicate actual concrete rooftop conditions, focusing on the condenser inlet temperature, compressor power consumption, and system coefficient of performance (COP). A 6-minute ON and 6-minute OFF intermittent spray cycle was employed to optimise water usage and minimise excessive humidity. Experimental measurements were conducted on a 9,000 Btu/h split-type unit equipped with a nozzle system connected to a 200 L …
Effect Of Argon Gas Flow Rate On Crystal Structure, Morphology, And Optical Properties Of Cigs Film For Photodetector Applications,
2025
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Malang 65145, Indonesia
Effect Of Argon Gas Flow Rate On Crystal Structure, Morphology, And Optical Properties Of Cigs Film For Photodetector Applications, Nurul Lathi’I Fatul Chamidah, Fadilah Wulan Cahyani, I Gusti Ayu Isnaini Fatha Ramadhani, Erma Surya Yuliana, Nasikhudin Nasikhudin, Safwan Abd. Aziz, Nandang Mufti
Journal of Mechanical Engineering Science and Technology (JMEST)
CIGS material can be used as a material for photodetector applications. The deposition of CIGS thin films remains challenging. Generally, argon is used as a gas to bombard the CIGS material through the sputtering method. This study fabricated photodetectors by varying the argon gas flow rate (50-80 sccm) to investigate its effect on device performance. XRD, SEM, UV-Vis, and photoresponse tests were characterized. Structural analysis using XRD showed a weak (112) diffraction peak, indicating that the resulting film was not fully crystalline, but rather consisted of a nanocrystalline phase, even partly amorphous, with small crystallite sizes. According to the SEM …
Numerical Analysis Of The Effect Of Vortex Generator On The Aerodynamic Performance Of Naca 6412 Airfoils Using Large Eddy Simulation,
2025
Mechanical Engineering, Adisutjipto Institute of Aerospace Technology, Jl. Janti / Jl. Majapahit Blok-R Yogyakarta 55198, Indonesia
Numerical Analysis Of The Effect Of Vortex Generator On The Aerodynamic Performance Of Naca 6412 Airfoils Using Large Eddy Simulation, Dedet Hermawan Setiabudi, Joan Bayuaji Nugroho, Eli Kumolosari, Lazuardy Rahendra Pinandhita, Okto Dinaryanto
Journal of Mechanical Engineering Science and Technology (JMEST)
Aerodynamic performance of an airfoil is significantly affected by flow separation, especially at high angles of attack. One common strategy to control flow separation is adding a triangular vortex generator (VG), which creates small vortices that help keep the airflow attached. The present study investigated the impact of triangular vortex generators on a NACA 6412 airfoil using Computational Fluid Dynamics (CFD) method. Large Eddy Simulation (LES) was applied due to its ability to show the vortices more clearly than other methods. It can also accurately capture the flow separation. To obtain the lift, drag, and lift-to-drag ratio (CL/CD) data, four …
Impact Of Cpo And B35 On Diesel Engine Rocker Arm Wear During Long-Term Operation,
2025
Mechanical Engineering, Faculty of Engineering, UPN Veteran Jawa Timur, Surabaya, 60294
Impact Of Cpo And B35 On Diesel Engine Rocker Arm Wear During Long-Term Operation, Fawwaz Aqilah Nurmansyah, Nur Fadilah Rizky Supramono, Muhammad Ikhsan, Erwan Adi Saputro, Wiliandi Saputro
Journal of Mechanical Engineering Science and Technology (JMEST)
The increasing number of motor vehicles has led to higher fossil fuel consumption, contributing to greenhouse gas emissions, climate change, and environmental degradation. As a renewable alternative, biodiesel offers a way to reduce these impacts. Indonesia, with its abundant natural resources, has significant potential for biodiesel production. Crude palm oil (CPO) is a promising feedstock due to its availability and relatively low environmental impact. However, the high costs associated with the transesterification process make direct use of pre-heated CPO an area worth exploring. This study investigates the impact of pre-heated pure CPO compared to B35 ("Dexlite") on rocker arm wear …
The Effect Of Heat Treatment Duration On The Psychochemical, Mechanical, And Biodegradability Of Polyvinyl Alcohol/Gambir Extract Biocomposite Films,
2025
Department of Mechanical and Industrial Engineering, Universitas Negeri Malang, Indonesia
The Effect Of Heat Treatment Duration On The Psychochemical, Mechanical, And Biodegradability Of Polyvinyl Alcohol/Gambir Extract Biocomposite Films, Ainul Kahfi Muhlasin, Poppy Puspitasari, Heru Suryanto, Diki Dwi Pramono, Dieter Rahmadiawan, Billie Jack Pasion
Journal of Mechanical Engineering Science and Technology (JMEST)
This study investigates PVA-based films with the addition of gambir and heat treatment to improve the characteristics of the film. Methods include the synthesis of PVA film with gambir addition (0.5%), treated by heat treatment for 40 minutes and 60 minutes. The film was characterised by physicochemical, mechanical properties, and biodegradability. Data was analyzed using ANOVA with a significance of 95%. Results indicate that the surface of PVA/gambir films is smoother and more homogeneous as the heat treatment duration increases. New peaks of functional groups were identified after the addition of gambir at the C-C and C-O groups. After heat …
Surface Modification Of Local Natural Fibers Via Alkali Treatment For Improved Mechanical And Molecular Properties Of Bamboo Fiber, Pineapple Leaf Fiber, And Sisal Fiber,
2025
Department of Manufacturing Engineering Technology, Universitas Negeri Malang, Semarang Street No. 5,
Malang, East Java, 65145, Indonesia
Surface Modification Of Local Natural Fibers Via Alkali Treatment For Improved Mechanical And Molecular Properties Of Bamboo Fiber, Pineapple Leaf Fiber, And Sisal Fiber, Jibril Maulana, Muhammad Ilman Nur Sasongko, Dewi Izzatus Tsamroh, Muchammad Yafis, Syekhan Maulana
Journal of Mechanical Engineering Science and Technology (JMEST)
A major development in materials science toward reinforcement materials in biopolymer composites has been caused by a worldwide trend toward sustainable manufacturing and the rise of the circular economy. However, their mechanical properties can often be affected by their hydrophilic properties, lack of surface compatibility, and their presence of molecular bonding, such as lignin and hemicellulose. Alkaline surface modification has been widely reported as an effective technique to increase structural stability and fibermatrix adhesion. This study evaluated the effects of alkalizing three types of local natural fibers—bamboo fiber (BF), pineapple leaf fiber (PALF), and sisal (SF)—with sodium hydroxide (NaOH) at …
Thermophysical, Rheological And Wear Resistance Of Canola Oil Biolubricant With Calcium Carbonate Additive Nanoparticle As Coolant In Cnc Machining,
2025
Department of Mechanical and Industrial Engineering, Universitas Negeri Malang, Indonesia
Thermophysical, Rheological And Wear Resistance Of Canola Oil Biolubricant With Calcium Carbonate Additive Nanoparticle As Coolant In Cnc Machining, Alfandi Jaelani, Poppy Puspitasari, Diki Dwi Pramono, Alief Muhammad, Muhammad Kozin, Muhammad Kashif
Journal of Mechanical Engineering Science and Technology (JMEST)
Vegetable oil-based cutting fluids are of great importance in supporting green and sustainable manufacturing. This research introduces a new groundbreaking vegetable lubricant formulated with canola oil as the base material, coupled with CaCO3 nanoparticles synthesized from scallop shell waste and used as a cutting fluid in the AISI 1045 CNC machining process steel sprayed with minimum quantity lubrication (MQL). This investigation delves into the thermophysical, rheological, and wear resistance of the developed bio-lubricant. The results of this analysis show density value increased in the canola + CaCO3 0.15% sample by 3.28% of the pure canola sample, as did the viscosity …
Improvement Of Thermal Energy Storage Performance In Al-Al2o3 Composites Through Additions Of Copper: Evaluation Of Microstructure And Thermal Properties,
2025
Department of Mechanical Engineering, Tadulako University, Soekarno Hatta Street, Palu, 94119, Indonesia
Improvement Of Thermal Energy Storage Performance In Al-Al2o3 Composites Through Additions Of Copper: Evaluation Of Microstructure And Thermal Properties, Muhammad Hasan Basri, Ramang Magga, Muhammad Syaiful Fadly, Zikri Arifansyah Djaba, Muhammad Iqbal Ibrahim, Hidayat Hidayat, Yandi Yandi
Journal of Mechanical Engineering Science and Technology (JMEST)
The study aims to evaluate the influence of adding copper aluminum–alumina composite (Al–Al₂O₃) against characteristic thermal properties through metallurgical powder. Three variations of the composition of weight copper were used, namely 5%, 10%, and 15%, with aluminum as the matrix and alumina as the reinforcement. Thermal test covering analysis of thermal conductivity, specific heat, and microstructure characterization using SEM-EDX. The results show that adding Cu increases thermal conductivity significantly, with the highest mark achieved in the 15% Cu composite (6.47 W/m.°C). However, the increase in Cu content above 10% causes the agglomeration of particles and enhancements in porosity, which harms …
Optimizing Zeolite Catalysts For Efficient Ldpe Plastic Waste Pyrolysis,
2025
Mechanical Engineering, Jambi Polytechnic, Alam Barajo, Jambi, 36361, Indonesia
Optimizing Zeolite Catalysts For Efficient Ldpe Plastic Waste Pyrolysis, Hilda Porawati, Mazwan Mazwan, Sukadi Sukadi
Journal of Mechanical Engineering Science and Technology (JMEST)
The problem of plastic waste, particularly from low-density polyethylene (LDPE) plastic bags, poses a significant challenge in environmental management due to its non-biodegradable nature and widespread use in daily life. This study evaluates the influence of catalyst types on the characteristics and energy efficiency of liquid fuel products produced from LDPE waste pyrolysis. The three treatments compared were no catalysts, natural zeolite catalyst, and synthetic zeolite catalysts, each subjected to three different temperature variations: 250°C, 300°C, and 350°C. The observed parameters in this study were volume, product mass, cetane index, density, sulfur content, viscosity, flash point, calorific value, and energy …
