Engineering Science and Materials Commons^™

Significantly Enhanced Oxygen Reduction Reaction Activity In Co-N-C Catalysts Through Synergistic Boron Doping, Chang Lan, Jing-Sen Bai, Xin Guan, Shuo Wang, Nan-Shu Zhang, Yu-Qing Cheng, Jin-Jing Tao, Yu-Yi Chu, Mei-Ling Xiao, Chang-Peng Liu, Wei Xing

Journal of Electrochemistry

The weak adsorption energy of oxygen-containing intermediates on Co center leads to a considerable performance disparity between Co-N-C and costly Pt benchmark in catalyzing oxygen reduction reaction (ORR). In this work, we strategically engineer the active site structure of Co-N-C via B substitution, which is accomplished by the pyrolysis of ammonium borate. During this process, the in-situ generated NH₃ gas plays a critical role in creating surface defects and boron atoms substituting nitrogen atoms in the carbon structure. The well-designed CoB₁N₃ active site endows Co with higher charge density and stronger adsorption energy toward oxygen species, …

Influence On Shot Peening And Blast Polishing For Rotating Bending Fatigue Strength Of Vacuum Carburized Steel With Circumferential Notch, Yuji Kobayashi, Hayato Taniguchi, Kiyotaka Masaki

15th International Conference on Shot Peening

In order to improve fuel efficiency in automobiles, weight reduction is necessary as well as improving engine efficiency. For transmission gears, thickness reduction is necessary for weight reduction. When the thickness is reduced, the cross-sectional area becomes smaller, and the load stress increases. Therefore, higher fatigue strength is required. Most gears carry out carburizing. Shot peening is often used to improve the fatigue strength of carburized heat-treated parts. After shot peening, compressive residual stress is introduced, but at the same time, surface roughness is increased. Therefore, the processing conditions of shot peening are very important. Blast polishing is a processing …

Investigations On The Fatigue Strength Of Threads Produced By Different Fabrication Techniques, Philippe Du Maire, Jürgen Hoffmeister, Andreas Öchsner, Michael Johlitz

15th International Conference on Shot Peening

The increasing importance of sustainability in engineering demands the development of long-lasting, high-performance components that reduce material and energy consumption over time. This study investigates how different thread manufacturing processes, i.e., cutting, rolling, and deep rolling, affect the fatigue strength of bolts made from 42CrMo4+QT steel. Cylindrical specimens with M12 threads were subjected to cyclic tensile loading with constant mean stress. Fatigue strength was evaluated using the staircase method, and supporting analyses included X-ray diffraction for residual stress, and full width half maximum examination and Vickers microhardness measurements. Results show that thread rolling significantly improves fatigue strength, achieving 113.8 MPa …

Numerical Assessment Of Shot Peening Contribution To The Fatigue Strength Of Gear Tooth Root, Gurutz Cortabitarte Laucirica, Xuban Telleria, Iñigo Llavori, Ibai Ulacia, Miren Larrañaga, Jon Ander Esnaola

15th International Conference on Shot Peening

Gears are commonly treated with shot peening (SP) and/or case hardening to enhance fatigue resistance. However, their effects are often conservatively assessed using standardized methods, which can limit their optimal application in industrial components. Particularly, the effect of SP over case-hardened gears remains insufficiently explored. Therefore, the present study evaluates the contribution of SP on single tooth bending fatigue (STBF) strength of raw and case-hardened spur gears, commonly used in automotive and heavy machinery industries. In the study four conditions are addressed: (i) untreated, (ii) case-hardened, (iii) shot-peened, and (iv) case-hardened and shot-peened. First, the residual stress field of the …

Enhancing The Fatigue Strength Of Am Materials Via Mechanical Surface Treatment, Fabian Keil, Jan Schubnell, Sascha Fliegener, Alexander Heiss

15th International Conference on Shot Peening

Additive manufacturing (AM) processes, while enabling the production of intricate geometries, frequently result in suboptimal surface quality, which can significantly restrict the fatigue strength of components when compared to those manufactured using traditional methods. This study explores the effectiveness of mechanical surface treatment (MST) techniques, specifically shot peening and deep rolling, in enhancing the fatigue performance of additively manufactured AlSi10Mg and 316L alloys. A combination of experimental investigations and finite element simulations was employed to evaluate the influence of these treatments on surface integrity, microstructure, and fatigue life. The results reveal that both MST approaches lead to substantial improvements in …

Expansion Of Laser Peening Application With A High-Power Microchip Laser On A Robotic Arm, Yuji Sano, Yoshio Mizuta, Satoshi Tamaki, Tomonao Hosokai, Tomoharu Kato, Yoshihiro Sakino, Volker Schneidau, Sebastian Holz, Jörg Behler

15th International Conference on Shot Peening

Laser peening (LP) introduces compressive residual stress (RS) onto the surface of metallic materials using nanosecond laser pulses irradiated through a water layer, thereby effectively suppressing fatigue crack initiation. However, conventional LP systems require large, stationary setups, restricting their use to indoor environments. To overcome this limitation, a portable LP device featuring a finger-sized microchip laser mounted on a collaborative robot arm has been developed. Equipped with a compact power supply and a water circulation/recovery system, the device can operate on-site with minimal setup. Successful processing across various materials has confirmed both compressive RS induction and fatigue life extension. Notably, …

Effects Of Laser Peening On Fatigue Properties Of Welded Aluminum Thin Plates, Kiyotaka Masaki, Yoshio Mizuta, Satoshi Tamaki, Yuji Sano

15th International Conference on Shot Peening

To improve the fatigue properties of welded aluminum alloy thin plates used in transportation machinery, handheld laser peening (HH-LP) was applied to 2 mm-thick A5083-O specimens prepared by bead-on TIG welding. Conventional laser peening often causes warping in thin plates, but the HH-LP treatment using low-energy laser pulses avoids this problem. The HH-LP treatment introduced compressive residual stresses of over 200 MPa on the heat-affected zone (HAZ) of the welded specimens. Fatigue tests under plane bending conditions revealed that the HH-LP treatment significantly improved the fatigue strength of the welded specimens, achieving a level comparable to that of the base …

Nonlinear Analytical Models Of The Seismically Isolated ``Frame-Boiler'' System With Cantilever-Type Hysteresis Dampers, Aleksandr Mikhailovich Anushchenko, Dmitrii Evgenievich Bondarev, Aleksandr Yurievich Schukin

Journal of Sustainable Construction Materials and Technologies

This study shows results of development of the ``frame-boiler'' system with hysteresis dampers analytical model. Hysteresis dampers are used as boiler antiseismic bracing. It is noted that simplified analytical models are necessary at the stage of preliminary iterative calculations, when a CAE-modeling is impractical due to significant time costs. The authors have proposed 2 options of analytical models: 2-mass model and 3-mass model. The differential equations of motion for each model are written below. The results of the calculation for seismic impacts are compared with the finite element model. It is shown that 3-mass model gives good match of results …

Advancing Sustainable Structural Solutions: Hemp Fiber-Reinforced Polymer (Hfrp) Reinforcement Bars For Concrete Applications Through Material Selection, Simulation, And Pathways For Future Development, Thomas Cadenazzi, Busra Keles

Journal of Sustainable Construction Materials and Technologies

This paper investigates innovative Hemp Fiber-Reinforced Polymer (HFRP) rebars as a sustainable alternative to conventional Carbon Steel (CS) and Glass Fiber-Reinforced Polymer (GFRP) rebars used as reinforcement in concrete structures. The feasibility of HFRP rebars is assessed, focusing on mechanical properties and sustainability advantages. A virtual tensile test on a modeled M19 HFRP rebar, conducted using Autodesk's Fusion 360, demonstrates tensile strength comparable to CS 235 and greater environmental sustainability than GFRP, despite a slight reduction in stiffness. The study also considers the potential of graphene fiber integration to enhance mechanical properties, underscoring HFRP's adaptability. Findings suggest that HFRP rebars, …

Comparative Analysis Of Life Cycle Assessment Of Traditional And Contemporary Timber Buildings, Sadık Akşar, Gökçe Tuna

Journal of Sustainable Construction Materials and Technologies

Wood has long been used as a primary building material, but with the Industrial Revolution and the spread of multi-story structures, its structural limitations became evident. In the 21st century, engineered timber products have reintroduced wood as a sustainable alternative, offering advantages such as lightness, rapid assembly, and recyclability. At the same time, buildings are responsible for significant environmental impacts, making assessment methods essential. Life Cycle Assessment (LCA) is one of the most widely used tools for evaluating these impacts across all stages of a building’s life cycle. This study applies LCA to timber construction systems, focusing on both traditional …

Sustainable Paving Block Development: Utilizing Rejected Coal As Filler And Assessing Its Impact On Paving Block’S Properties, Siti Nikmatin, Allen Kurniawan, Heriansyah Putra, Rima Fitria Adiati, Riawan Ma’Ruf, Dwi Arso Yedi Irwanto

Journal of Sustainable Construction Materials and Technologies

This study investigated the potential use of rejected coal as a fine aggregate filler in paving block production. Comprehensive characterization of the rejected coal was conducted, including toxicity, physical, chemical, and mineralogical analyses of the coal. The results showed that the rejected coal met environmental safety standards (TCLP) and had suitable properties as an aggregate. Paving blocks were produced by incorporating different proportions of rejected coal fillers and were tested for compressive strength, water absorption, and density. The optimal mix with 35% rejected coal filler as a replacement of stone ash achieved a compressive strength of 14.61 MPa, water absorption …

Numerical Comparative Study Of The Thermal Performance And Load-Bearing Capacity Of Hollow Clay Bricks Used In Construction In Libya, Osama Lawej, Mahmoud Ahmed, Ismael Ehtiwesh

Journal of Sustainable Construction Materials and Technologies

The optimization of structural and thermal performance in building components is a key challenge in sustainable construction, particularly in hot climate regions like Libya. Hollow clay bricks are widely used due to their local availability and affordability; however, their internal geometry is often not optimized for thermal resistance or mechanical integrity. This study addresses this gap by numerically investigating the effect of cavity geometry on the load-bearing capacity and thermal insulation performance of hollow clay bricks. Three configurations were analyzed, including two commercial designs from the Libyan market and a newly proposed arched cavity design. Finite Element Method (FEM) simulations …

Developing A Modular Circular Wall Over-Clad System For Facade Thermal Upgrade In Deep Energy Retrofit, Patrick Daly

Journal of Sustainable Construction Materials and Technologies

The EU has implemented several policy and legislative initiatives aimed at decarbonisation and circularity transition of the Built Environment including a strategy for large scale renovation of the building / housing stock. Modularised construction solutions are argued to be a potential acceleration pathway toward this objective. Yet there remains issues and challenges in implementing such strategies in a complex and heterogeneous stock and sector. This research investigates this decarbonisation pathway, examining the feasibility and potential of applying a modularised construction over-clad system, based on advanced circularity, in the deep energy retrofit of social housing. The research is based on a …

Effect Of Gelam Wood And Rice Husk Composition With Molding Pressure On The Combustion Performance Of Biopellets, Rachmat Subagyo, Rudi Siswanto, Ma’Ruf Ma’Ruf, Mastiadi Tamjidillah, Abdul Ghofur, Femiana Gapsari, M. Zainul Rusdi, Azie Aprianto, Wardoyo Wardoyo, Naila Salsabila

Journal of Mechanical Engineering Science and Technology (JMEST)

This study investigates the effects of gelam wood (Melaleuca leucadendron) and rice husk composition in biopellet production, focusing on compaction pressures of 60, 80, and 100 kg/cm². Five biomass ratios (G100–RH0, G80–RH20, G60–RH40, G50–RH50, G0–RH100) were tested for moisture, ash, fixed carbon, volatile matter, calorific value, ignition time, burning rate, and combustion temperature. Results showed that moisture content ranged from 0.98% (G0–RH100, 60 kg/cm²) to 12.28% (G100–RH0, 80 kg/cm²), while ash content varied between 2.47% (G100–RH0, 60 kg/cm²) and 20.93% (G0–RH100, 80 kg/cm²). The highest calorific value reached 3968 cal/g (G100–RH0, 60–80 kg/cm²), though below the SNI 8675:2018 minimum of …

Experimental And Numerical Investigation On The Effect Of Projectile Mass And Apex Angle On Penetration Depth Into Sandy Soils, Abdul-Rahman K. Osman, Ahmed Elshesheny Dr, Mohamed S. Zahran Dr, Nabil M. Nagy Prof.

Journal of Engineering Research

Projectile penetration in granular soils remains a critical concern in defense engineering and ballistics research. This study presents an experimental and numerical investigation of rigid cone-tip projectile penetration into very dense sand, examining the influence of apex angle and projectile weight on penetration depth. Laboratory experiments were conducted using metallic projectiles with apex angles of 10°, 30°, 60°, and 90° and weights of 2.445, 3.87, 5.33, and 6.81 kg, dropped from a height of 4.295 m into a 500×500×500 mm wooden tank filled with sand to 400 mm height at 95% relative density. Through systematic testing, two empirical correlation …

A Polar Turbulence Invariant Map With Applicability To Realisable Machine Learning Turbulence Models, James G. Wnek, Christopher Schrock, Eric M. Wolf, Mitch Wolff

Mechanical and Materials Engineering Faculty Publications

Invariant maps are a useful tool for turbulence modelling, and the rapid growth of machine learning-based turbulence modelling research has led to renewed interest in them. They allow different turbulent states to be visualised in an interpretable manner and provide a mathematical framework to analyse or enforce realisability. Current invariant maps, however, are limited in machine learning models by the need for costly coordinate transformations and eigendecomposition at each point in the flow field. This paper introduces a new polar invariant map based on an angle that parametrises the relationship of the principal anisotropic stresses, and a scalar that describes …

Detecting Electrical Submersible Pump (Esp) Failures And Estimating Run Life Using Artificial Neural Networks, Mostafa Ahmed Sobhy

Theses and Dissertations

Electric Submersible Pumps (ESPs) are one of the important artificial lift methods for sustaining production in mature and high-water-cut wells; but may suffer frequent failures due to mechanical, electrical, hydraulic, chemical, and operational failures. These failures can yield substantial deferred production and intervention costs. Plenty of ESP installations are fitted with downhole sensors. Yet, it is observed that the current industry practice underutilizes the wealth of available sensor and operational data and lacks standardized, explainable failure-type identification and classification.

In this thesis, a comprehensive Machine Learning (ML) and Deep Learning (DL) framework was introduced for ESPs that simultaneously estimates remaining …

Tensile Creep Of A Hybrid Polymer-Matrix/Ceramic-Matrix Composite At Elevated Temperature, Waleed S. Alshehri

Theses and Dissertations

Advanced aerospace systems require structural materials that can perform reliably in high-temperature environments for long durations. The performance of standard polymer matrix composites (PMCs) in these conditions is often limited by their susceptibility to time-dependent deformation, such as creep. The objective of this research is to characterize the high-temperature creep behavior of a novel unitized material system comprising a polymer matrix composite (PMC) and a ceramic matrix composite (CMC) co-cured together. The PMC part consists of the polyimide matrix reinforced with laminated carbon fibers woven in an eight harness satin weave (8HSW). The CMC part consists of a zirconia-based ceramic …

A Green Concrete Mixture Using Rice Husk As Partially Cement Replacement, Khloud Khalid Eldamshiry, Zeina Salama, Amany Micheal, Rania Rushdy Moussa, Ayatallah Raafat

Architectural Engineering

Egypt's agricultural waste production has increased significantly in recent decades, leading to improper disposal methods and environmental pollution. Rice husks are the most common agricultural solid waste in Egypt, contributing to "black clouds" and causing health issues. On the other hand, Cement, a crucial component of construction materials, generates unsound residues and greenhouse gas emissions. Green concrete with rice husks could be a profitable solution for environmentally sound construction, reducing cement consumption and increasing the durability and integrity of new materials. This study investigates the use untreated rice husk fibres with a concrete mixture, avoiding burning and contributing to environmental …

Superhydrophilic Porous Coooh Nano-Architecture With Abundant Oxygen Vacancies For Enhanced Urea Electrooxidation At Ampere-Level Current Densities, Wen-Jing Lv, Xiao-Man Tang, Xue-Tong Wang, Wen-Cai Liu, Jian-Wen Zhu, Guo-Jing Wang, Yuan-Zhi Zhu

Journal of Electrochemistry

The conversion of urea-containing wastewater into clean hydrogen energy has gained increasing attention. However, challenges remain, particularly with sluggish catalytic kinetics and limited long-term stability of urea oxidation reaction (UOR). Herein, we report the loosely porous CoOOH nano-architecture (CoOOH LPNAs) with hydrophilic surface and abundant oxygen vacancies (O_v) on carbon fiber paper (CFP) by electrochemical reconstruction of the CoP nanoneedles precursor. The resulting three-dimensional electrode exhibited an impressively low potential of 1.38 V at 1000 mA·cm⁻² and excellent durability for UOR. Furthermore, when tested in an anion exchange membrane (AEM) electrolyzer, it required only 1.53 V at …