Engineering Science and Materials Commons^™

Investigation Of The Production Technology Of Environmentally Safe Urethane Oligomers Based On Local Raw Materials, Bakhtiyor Kudratovich Shaykulov, Dilafruza Ruziboevna Akbarova Gulboeva, Fayzulla Nurmuminovich Nurqulov

Technical science and innovation

This paper investigates the step-by-step poly condensation pathway for synthesizing environmentally friendly, non-isocyanate urethane oligomers derived from local and safe raw materials: urea and ethylene glycol. The influence of thermodynamic parameters on the target product yield was systematically evaluated to determine the optimum technological matrix. Specifically, a 1:2 reactant mass ratio, a stable stationary temperature of 150-155 °C, and a reaction duration of 2 hours under an inert nitrogen atmosphere resulted in a sustainable and reproducible yield of 72%. Thermal degradation and competitive side-product condensations were activated above 160 °C, leading to a sharp drop in overall chemical efficiency. The …

Integrating Gis With Interim Payment Valuation In Road Construction Projects: A Conceptual Framework, Abdulrahman I. Iro, Juma M. Matindana, Julian Ijumulana

Tanzania Journal of Engineering and Technology (TJET)

Abstract

Interim Payment Valuation is a critical process in road construction contract administration, yet conventional valuation practices remain heavily dependent on manual measurements, fragmented documentation, spreadsheets, and professional judgement. These limitations can affect measurement accuracy, transparency, traceability, and the timeliness of payment certification. Although Geographic Information Systems have increasingly been applied to construction planning, quantity measurement, progress monitoring, infrastructure management, and decision support, their integration with contractual and financial processes for interim payment valuation remains insufficiently explored. This study therefore develops a conceptual framework for integrating GIS with Interim Payment Valuation in road construction projects. A PRISMA-guided structured literature review …

Voltage-Related Power Quality Issues And Impacts On Distribution Networks With Sensitive Loads - A Review, Godwin Elinazi Mnkeni, Jackson Justo, Aviti Thadei Mushi, Bakari M. M. Mwinyiwiwa

Tanzania Journal of Engineering and Technology (TJET)

Voltage disturbances are the most important power quality (PQ) complications that customers and power utilities face in this smart era. The growing adoption of sophisticated electronic equipment and integration of renewable energy sources (RES) into power grids has increased the susceptibility of power distribution networks (PDNs) to voltage sags, swells, interruptions, flicker, and voltage imbalance. These disturbances, mainly caused by upstream faults, switching operations, and RES integration, compromise voltage PQ and system reliability. Consequently, they accelerate equipment degradation, increase electronic waste (e-waste), raise reactive power demand and maintenance costs, increase power losses, and impose substantial economic losses on customers and …

Experimental Study On The Behavior Of High-Strength Reinforced Concrete Beams With A Longitudinal Void, With And Without Micro Steel Fibers, At Different Shear Spans, Farah M. Hussein, Saif Altai, Shatha Alasadi, Ayoob A. Ibrahim, Arshad Nadhom Shubber

Journal of Sustainable Construction Materials and Technologies

This study examines the impact of creating a longitudinal void in high-strength reinforced concrete (RC) beams to decrease concrete volume. Testing involved three groups: solid beams (SB), beams with a 75 mm void (VB), and beams with a void incorporating 1.2% micro-steel fibers (VBSF), across various shear spans (a/d) of 1.8, 2.7, and 3.6. Results indicated that increased a/d led to a 54.2% reduction in peak loads and a 119.2% increase in deflection for solid beams. The void negatively affected load-bearing at a/d = 1.8 with a 25% peak load reduction and brittle failure. At a/d = 2.7, effects were …

Efficient Acidic H2O2 Electrosynthesis Over Co Atoms Anchored On Nitrogen-Doped Hierarchical Porous Carbon, Xiao Huang, Zi-Hao Zhan, Hao-Xu Niu, Guan-Yu Luo, Jin-Tao Huang, Bo-Xuan Jin, De-Li Wang

Journal of Electrochemistry

The two-electron oxygen reduction reaction (2e⁻ ORR) presents a promising route for the on-site production of hydrogen peroxide (H₂O₂), offering a green alternative to energy-consuming anthraquinone process. However, the high selectivity toward the competing 4e⁻ ORR over the desired 2e⁻ pathway leads to low Faradaic efficiency for H₂O₂, posing a critical challenge in catalyst design. In this work, a nitrogen-doped hollow hierarchical porous carbon with anchored Co atoms (CoN/HPC) was constructed for high-performance H₂O₂ production. The as-prepared Co-N/HPC catalyst showed excellent 2e⁻ ORR performance, achieving …

Engineering Small-Sized Cations With Strong Solvation For High-Voltage Supercapacitors, Tong Huo, Pan Liu, Hao Chen, Peng Zhang, Zhen-Lei Chen, Guo-Fu Sun, Zhi-Qiang Shi, Jing Wang

Journal of Electrochemistry

Supercapacitors (SCs) have attracted much attention in the field of energy storage due to their high power density and long cycle life. However, their relatively low energy density limits their application in a wider range of fields. Methods to increase energy density include enhancing specific capacitance and extending operating voltage window. Herein, we report a novel electrolyte salt, tetramethylammonium bis(fluorosulfonyl)imide (TMA-FSI), the resulting electrolyte formed with propylene carbonate (PC), designated as TMF, exhibited a wide electrochemical stability window (ESW) of 5.09 V. On the one hand, we found that the small size of TMA⁺ enables it to enter the …

Dense Platinum Nanoparticles Confined In Mn-N-C Nanocages For Robust Heavy-Duty Pemfcs, Lei Zhao, Zhen-Min Cao, Jia-Yu Zuo, Ming-Liang Yang, Hong-Yan Qiao, Jun-Song Chen, Rui Wu

Journal of Electrochemistry

High-loading Pt cathodes are essential for heavy-duty proton exchange membrane fuel cells but suffer from a critical tradeoff between ionomer sulfonate poisoning and nanoparticle instability. Herein, we report a spatial confinement strategy to encapsulate dense Pt nanoparticles (~51.8 wt%) within Mn/N-co-doped mesoporous carbon nanocages (denoted as Pt-MnNC). This architecture excludes bulky ionomers to create an ionomer-shielded environment against sulfonate poisoning, while Mn-N_x-mediated strong metal-support interactions anchor the Pt nanoparticles to prevent agglomeration and further boost durability. In the 5 × 5 cm² membrane electrode assembly tests, the Pt-MnNC catalyst delivers an exceptional power density of 1.26 W·cm …

Physical Modeling To Represent Molten-Slag Entrapment Behavior Into Molten-Steel Under Simultaneous Similitude Condition Of Multiple Dimensionless Numbers, Yuichi Tsukaguchi, Sho Nakano

Progress in Scale Modeling, an International Journal

Physical model construction and experiment are essential for scientific investigations of flow phenomena such as high temperature two phase flow of molten metal and inert gas. It has been a common method to construct a physical model with a convenient scale then proceed experiments under similitude condition of one or two dimensionless number(s) of dominant forces to represent. It is an ideal experimental method to satisfy the simultaneous similitude condition of multiple dimensionless numbers concerned with the objective flow phenomena but has been considered difficult or impossible to realize for many years. Contrarily, the concept of the simultaneous similitude of …

Aerodynamic Effects Optimisation Of Water-Powered Funicular Car Body Exposed To Headwind And Crosswind, Theodorus Agung Wicaksono, Bagus Wahyudi, Syamsul Hadi, Wirawan Wirawan, Hangga Wicaksono

Journal of Mechanical Engineering Science and Technology (JMEST)

Water-powered funicular railways are an environmentally friendly mode of transport whose efficiency heavily depends on the principle of gravity. However, their operation is vulnerable to natural wind disturbances that can hinder speed or cause a risk of overturning on steep, curved tracks. This study aims to analyse the influence of funicular car model design on the rolling moment exerted on the rails as the car turns to enter a track branch. The research methodology involves aerodynamic simulations using SolidWorks flow simulation, comparing three body models: WAHYUDI, FUNAERO, and AEROFUN. Simulations were conducted with variations in turn angles (10° to 30°) …

Parametric Study On The Plastic Hinge Length Of Precast Concrete Columns With Grouted Sleeve Connections, Rizky Tri Amalia, Harun Alrasyid

Journal of Sustainable Construction Materials and Technologies

The use of precast concrete structures with grouted sleeve (GS) connections has gained significant traction in the acceleration of bridge construction. The plastic hinge length (Lp) is a critical parameter for assessing the seismic performance and deformation capacity of such structural members. The previous study has proposed empirical equations for Lp in monolithic columns; however, a comprehensive understanding of the influential parameters on Lp in precast concrete columns with GS connections remains limited. This study presents a detailed parametric investigation to evaluate the effects of key design parameters on the plastic hinge length of a precast concrete columns with GS …

Synthesis Of Fe-Doped Porous Carbon Catalyst Derived From Coconut Shell Waste Using Ferric Nitrate Nonahydrate (Fe(No3)3.9h2o) As An Iron Precursor, Ilham Lestadi Putra, Sukarni Sukarni, Heru Suryanto

Journal of Mechanical Engineering Science and Technology (JMEST)

Renewable energy from lignocellulosic biomass is a promising alternative to fossil fuels. Coconut shell (CS) waste is a favorable precursor for porous carbon due to its high carbon content, abundance, and non-food nature. However, conventional biochar often has limited surface area and catalytic active sites, hindering its effectiveness as a catalyst. While Fe-based modifications are promising, the use of ferric nitrate-assisted activation of coconut-shell-derived porous carbon remains underexplored. This research focused on developing an Fe-doped porous carbon catalyst from CS via ultrasound-assisted impregnation, followed by activation in a tube furnace. CS biochar was produced through pyrolysis at 550 °C and …

In Situ Electrochemical Characterization Techniques For Active Hydrogen In Electrocatalytic Nitrate Reduction To Ammonia, Hong-Mei Li, Mei Yi, Zhao-Yu Jin, Ming-Hao Xie, Khalid M. Omer, Yong Guo, Pan-Pan Li

Journal of Electrochemistry

Electrocatalytic nitrate reduction to ammonia (NitRR) represents a sustainable pathway that integrates environmental remediation with the production of high-value ammonia. However, the activity and selectivity of this process are limited by the generation, consumption, and dynamic equilibrium of the key transient intermediate—active hydrogen (*H). Precise modulation of *H necessitates a comprehensive understanding of its behavior, which relies fundamentally on advanced in situ electrochemical characterization techniques. However, a systematic review dedicated to the rational selection and application of in situ electrochemical techniques for the specific characterization of *H in NitRR, with clear definitions of each technique's "detectable targets, quantitative accuracy, and …

Neural Network Driven By Electrochemical Performance Data For Predicting The Discharge Termination Time Of Seawater Electrolyte-Based Metal-Air Batteries, Peng-Peng Shen, Yi-Chi Pan, Yu-Rong Liu, Lu-Dan Zhang, Ning Niu, Guan-Jun Wang, De-Kun Yang, Xin-Long Tian, Peng Rao

Journal of Electrochemistry

Seawater electrolyte-based metal-air batteries exhibit great promise for marine energy supply systems. However, conventional statistical analysis methods, though applicable to seawater metal-air battery lifetime prediction, have inherent limitations of insufficient prediction accuracy and large error. Herein, a deep time-series regression framework based on InceptionTime and incorporating prior-biased attention pooling is proposed to construct a nonlinear mapping between electrochemical performance sequences and the discharge termination time of catalysts. Specifically, chronoamperometric profiles are employed to extract long-term stability features, while prior knowledge derived from linear sweep voltammetry is introduced to strengthen the attention weighting over critical potential regions. Under a nested leave-one-catalyst-out …

Microwave-Assisted Synthesis Of Core-Shell Structured Pd@Pdptcufe Recessed Truncated Octahedral Nanocrystals For Multifunctional Electrocatalysis, De-Zhong Hu, Wen-Dan Jiang, Wei Keat Ng, Jun Yang, Xiong-Wu Kang

Journal of Electrochemistry

Developing cost-efficient and durable multifunctional electrocatalysts of hydrogen evolution reaction, oxygen reduction reaction and oxygen evolution reaction is crucial for improving energy conversion efficiency in electrolytic water splitting electrolyzer and advancing rechargeable zinc-air batteries. Polyhedral shaped nanocrystals with well-defined crystal facets represent a type of model catalysts that enables the exploration of structure-activity relationships. However, it is still very challenging to prepare alloy nanocrystals with multiple metal components due to their complicated redox potentials and mixing enthalpy. Herein, we report a rapid microwave-assisted polyol reduction method for syntheses of core-shell Pd@PdPtCu, Pd@PdPtCuNi, Pd@PdPtCuCo and Pd@PdPtCuZn octahedral nanocrystals, and recessed truncated-octahedral …

Techno-Economic Analysis Of The Utilization Of Waste-To-Energy In Jakarta Industrial Estate Pulogadung, Wahyu Punjung Pesonagrata, Mohammad Akita Indianto

Journal of Materials Exploration and Findings

Indonesia has a serious waste problem, which ranking second in marine pollution. Due to significant environmental impacts, a solution to overcome the complexity of waste problems is needed. This study took sample on waste management in Jakarta Industrial Estate Pulogadung (JIEP). JIEP is an Industrial area which covers 443 hectares of land in East Jakarta. This study aims to address Indonesia's serious waste problem by exploring the potential utilization of waste in the Jakarta Industrial Estate Pulogadung (JIEP) as Refuse-Derived Fuel (RDF) for a waste-to-energy (WtE) power plant. The proposed method used a steam power plant with RDF as fuel …

Percolation-Induced Thermo-Rheological Transitions In Biobased Graphene Nanoplatelet Nanofluids, Abiodun A. Saka, Tobechukwu K. Abor, Anthony C. Okafor, Monday U. Okoronkwo

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Biobased lubricants with thermally responsive rheology are increasingly needed for high-efficiency mechanical systems. Graphene nanoplatelet (GnP) nanofluids in vegetable oils are promising candidates, yet their percolation-driven thermo-rheological transitions remain insufficiently understood. In particular, the coupled concentration–temperature landscape controlling network-mediated flow transitions has not previously been established. Here, surfactant-free GnP nanofluids were prepared in high-oleic soybean oil (HOSO) at concentrations of 0.025–2.15% v/v (ϕ), and their rheological response was mapped between 25°C and 80 °C under steady-shear and oscillatory conditions. Below the percolation threshold (ɸ ≤ 0.1% v/v), the nanofluids exhibit near-Newtonian behavior, moderate reversible viscosity enhancement, and classical Arrhenius-type temperature …

Improving The Concrete Compressive And Flexural Strength With A Low Fraction Addition Of Carboxylated Nitro-Oxidized Cellulose Nanofibrils From Banana Rachis, Ngesa Ezekiel Mushi, Emmanuel Kagya

Tanzania Journal of Science

Conventionally, concrete strength depends on the bonding interface, especially in hydrated products such as calcium silicate hydrate (CSH). As a result, concrete is sensitive to tensile load. With its unique properties, a low fraction of carboxylated nitro-oxidized cellulose nanofibrils (NOCNF) from the banana rachis is employed to improve the mechanical performance of the concrete nanostructurally. Compressive and flexural strength using the NOCNF content at 0, 0.05, and 0.1 wt.%, cured for 7 and 28 days, were evaluated. Notably, the compressive strength increased by 16 % and the flexural strength by 13 % at 0.1 wt.% NOCNF compared to plain concrete …

Quantification Of Uncertainty Propagation For Transient Heat Transfer In A Hollow Sphere, Rama Subba Reddy Gorla, Lochlan Joyce, Elie John Barbari

Faculty Publications

Uncertainty propagation and transient heat transfer for a hollow sphere are analyzed. The stochastic Biot number, stochastic linear non-dimensional initial conditions, and various boundary conditions are introduced to define uncertainty propagation influencing the temperature distribution throughout the hollow sphere. The resulting uncertainty amplitude was observed to have transient evolution in time. The uncertainty can either increase or decrease depending on the stochastic parameters. Results are presented for the variation in temperature due to uncertainties in the initial conditions and particular boundary conditions.

Restoration And Instrumentation Of A Cantilever Beam Model Using Strain Gauge Measurement, Ana Paula Guevara

Discovery Day - Daytona Beach

This project aims to restore and modernize an instructional cantilever beam model with a C‑shaped cross‑section used in Aerospace Structures courses, addressing the need for updated, hands‑on teaching tools that connect theoretical stress–strain concepts to real experimental data. The existing model, previously limited to qualitative demonstrations, is being rehabilitated and instrumented with a bonded strain gauge capable of detecting resistance changes under applied bending loads. These signals are processed through an Arduino‑based data acquisition system, which converts electrical resistance into strain values and displays them in real time on an LCD interface. The project’s objectives are to return the beam …

Additive Manufacturing Of Metals: Mechanical Properties And Their Implications, Sean Chih

Discovery Day - Daytona Beach

Additive manufacturing of metals is a relatively new and groundbreaking approach to manufacturing high-performance components. However, variability in mechanical properties from the process creates a barrier before this manufacturing technique can be widely applied. Understanding when and where to use this manufacturing is also important to create components with efficiency and without harmful defects. The objective of this research is to evaluate the effects of build orientation, printing parameters, internal defects, thermal history, and residual stresses, post-processing heat treatments, and fatigue behavior on additively manufactured components. Literature-based research is conducted on commonly used metals for additive manufacturing, such as stainless …