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SSRN 2024年

作者： Wang, Jianbin Teng, Yingxue Chang, Jun Li, Jing Sun, Mingjing School of Materials and Metallurgical Engineering University of Science and Technology Liaoning Anshan China School of Chemical Engineering University of Science and Technology Liaoning Anshan China Faculty of Infrastructure Engineering Dalian University of Technology Liaoning Dalian116024 China

In this paper a novel method was adopted to expedite the hydration process within the MOS cement aim to use MOS mortar in subtropical region projects. The samples were immersed in a distilled water at 60℃ and 20℃，and the cycle was repeated every 12 hours which was conducive to the acceleration of hydration. The results showed that with the increase of humid-heat cycles number, MgO inside the matrix gradually disappeared and the Mg(OH)2content continuously rise, causing a rise in 100mm-level porosity and a reduction in mm-level pore size resulted in the growth of 517 whiskers in 3-6 mm-level, and the continuous filling of nm-level pores. Until 20 cycles, the porosity at the mm-level rises steadily reached a maximum value of 21.05%, the nm-level porosity dropped to its lowest point, and the strength back up to a high. After that, the decomposition of the 517 phase and the carbonization of Mg(OH)2 lead to a rapid increase in pore space, ultimately causing crack formation and a rapid decrease in mechanical properties. As a result, the evolution of 517 phase affects the pore structure of cement, and the concentration of free Mg2+ is the main factor determining the evolution behavior of 517 phase. © 2024, The Authors. All rights reserved.

关键词： Sulfur compounds

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Mechanistic insights into CO2 photoreduction to formic acid using ZnO catalysts

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Chemical engineering Research and Design 2025年 218卷 664-673页

作者： Astuti, Andi Rina Ayu Ariono, Danu Wenten, I. Gede Sasongko, Dwiwahju Saputera, Wibawa Hendra Kurnia, Kiki Adi Department of Chemical Engineering Faculty of Industrial Technology Universitas Muslim Indonesia Jl. Urip Sumoharjo Km. 05 Makassar90231 Indonesia Department of Chemical Engineering Faculty of Industrial Technology Institut Teknologi Bandung Jl. Ganesha 10 Bandung40132 Indonesia Research Center for Nanosciences and Nanotechnology Institut Teknologi Bandung Jl. Ganesha 10 Bandung40132 Indonesia Research Group on Energy and Chemical Engineering Processing System Department of Chemical Engineering Faculty of Industrial Technology Institut Teknologi Bandung Jl. Ganesha 10 Bandung40132 Indonesia Center for Catalysis and Reaction Engineering Institut Teknologi Bandung Jl. Ganesha 10 Bandung40132 Indonesia Research Center for New and Renewable Energy Institut Teknologi Bandung Jl. Ganesha 10 Bandung40132 Indonesia Center of CO2 Utilization and Flare Gas Institut Teknologi Bandung Jl. Ganesha 10 Bandung40132 Indonesia Postgraduate program of Science in Sustainability Faculty of Infrastructure Planning Universitas PERTAMINA Jl. Teuku Nyak Arif Jakarta12220 Indonesia

The conversion of CO2 into formic acid (HCOOH) is vital due to rising atmospheric CO2 levels and the high market value of HCOOH among CO2 utilization products. A photocatalytic technology offers a promising method for this transformation using sustainable energy. However, the lack of the exact mechanism of CO2 reduction into HCOOH using heterogeneous catalyst and light energy remains unclear. Therefore, this study explores the reaction pathways validated with experimental data and density functional theory (DFT) calculation. Based on the experiment, ZnO semiconductor catalysts achieved the highest formic acid production, with a concentration of 345.44 µmol/L·gcat after 4 hours of operation at a gas flow rate of 800 mL/min. Among the four proposed mechanisms, CO₂ photoreduction to HCOOH follows the Eley-Rideal adsorption mechanism, where only reactant of 2H⁺ undergoes chemisorption, while CO₂ remains physisorbed. Additionally, HCOOH exhibits strong adsorption on ZnO surface, as confirmed by experimental data and adsorption energy calculations. DFT calculations using CRYSTAL14 and the B3LYP method support this finding. The weak physisorption energy (less than 0.5 eV) allows CO2 to undergo direct reactions on the catalyst surface. This study elucidates the role of each component in enhancing CO2 photoreduction to HCOOH and provides a foundation for further research on CO2 utilization. © 2025

关键词： Local density approximation

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Performance Variations of Light Burned Magnesium Under Different Calcination Parameters and its Effects On Magnesium Oxysulfate Cement Preparation

SSRN

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SSRN 2024年

作者： Zhou, Junfeng Guan, Yan Hu, Zhiqi Bi, Wanli Chang, Jun Zhang, Tingting School of Materials and Metallurgy University of Science and Technology Liaoning Liaoning Anshan114051 China Faculty of Infrastructure Engineering Dalian University of Technology Liaoning Dalian116024 China

This study systematically investigated the impact of different calcination temperatures and holding times on MgO reactivity, as well as the influence of varying MgO characteristic on the properties of magnesium oxysulfate cement (MOSC). Results indicated that at temperatures of 700-900℃, magnesite underwent decomposition, resulting in increased lattice distortion, and heightened reactivity. At temperatures of 1000-1100℃, magnesia began sintering, nucleating, and experienced reduced crystal distortion, leading to decreased reactivity. Notably, the appearance of the pseudomorphic mother rock at calcination temperatures of 900℃ and 1000℃ was associated with decreased magnesia reactivity. Moreover, the compressive strength of MOSC prepared using MgO calcined at 900℃ for 6 h increased to 77 MPa after 28 d of air curing. The hydration reactivity and lattice distortion of MgO could be regulated through changing the calcining temperature and holding time, which provided a theoretical basis for the preparation of magnesium oxysulfate cement with excellent mechanical properties. © 2024, The Authors. All rights reserved.

关键词： Magnesia

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Analysis of Mobile and Internet Network Coverage: Propagation of Electromagnetic Waves and Concept of Digital Divide in Burundi

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Open Journal of Antennas and Propagation 2024年第1期12卷 1-18页

作者： Apollinaire Bigirimana Jérémie Ndikumagenge Sami Tabbane Romeo Nibitanga Hassan Kibeya Center for Research in Infrastructure Environment and Technology (CRIET) Doctoral School of the University of Burundi Bujumbura Burundi Center for Research in Infrastructure Environment and Technology (CRIET) University of Burundi Bujumbura Burundi Higher School of Communications of Tunis Technological City of Communications Ariana Tunisia Faculty of Engineering Sciences Universit du Burundi Bujumbura Burundi

Mobile and Internet network coverage plays an important role in digital transformation and the exploitation of new services. The evolution of mobile networks from the first generation (1G) to the 5th generation is still a long process. 2G networks have developed the messaging service, which complements the already operational voice service. 2G technology has rapidly progressed to the third generation (3G), incorporating multimedia data transmission techniques. It then progressed to fourth generation (4G) and LTE (Long Term Evolution), increasing the transmission speed to improve 3G. Currently, developed countries have already moved to 5G. In developing countries, including Burundi, a member of the East African Community (ECA) where more than 80% are connected to 2G technologies, 40% are connected to the 3G network and 25% to the 4G network and are not yet connected to the 5G network and then still a process. The objective of this article is to analyze the coverage of 2G, 3G and 4G networks in Burundi. This analysis will make it possible to identify possible deficits in order to reduce the digital divide between connected urban areas and remote rural areas. Furthermore, this analysis will draw the attention of decision-makers to the need to deploy networks and coverage to allow the population to access mobile and Internet services and thus enable the digitalization of the population. Finally, this article shows the level of coverage, the digital divide and an overview of the deployment of base stations (BTS) throughout the country to promote the transformation and digital inclusion of services.

关键词： Coverage of Mobile Networks and Internet Digital Divide Rural and Isolated Areas Antenna Connectivity and Digital Inclusion

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Assessment of satellite-based rainfall products for drought monitoring in the Siak Watershed, Indonesia

Environmental Challenges

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Environmental Challenges 2025年 19卷

作者： Mashuri Karlina Sujono, Joko Department of Civil and Environmental Engineering Faculty of Engineering Universitas Gadjah Mada Yogyakarta Indonesia Departement of Civil Engineering Faculty of Infrastructure and Regional Technology Institut Teknologi Sumatera Lampung Selatan Indonesia

Satellite-based rainfall products (SRPs) provide critical precipitation data, particularly in regions with limited or absent rainfall measurement stations. The accuracy of these products necessitates rigorous validation against observed rainfall data. This study evaluates four SRPs—CHIRPS, GPM IMERG F, PERSIANN CCS CDR, and GSMaP—in the Siak Watershed, Riau Province, Indonesia, and investigates their utility in drought monitoring. Bias correction methods, including Modified Linear Correction (MLC), Distribution Mapping (DM), and Modified Linear Correction – Rainfall Intensity Characteristics (MLC-RIC), were applied during calibration and validation phases to enhance SRP accuracy. Validation was performed using data from four rainfall measurement stations spanning 2003 to 2020, with the best-performing SRPs identified through a ranking system based on 34 test parameters at daily, monthly, and annual time scales. The findings indicate that the MLC-RIC method, which introduces six correction factors based on rainfall intensity characteristics, outperforms other bias correction approaches. Among the SRPs, GSMaP demonstrated superior accuracy at daily and annual time scales, while GPM IMERG F excelled in capturing monthly rainfall patterns. Overall, GSMaP emerged as the most reliable product for rainfall estimation and drought monitoring, with GPM IMERG F and PERSIANN CCS CDR ranking second and third, respectively. These results were consistent across pre- and post-correction analyses. Beyond drought analysis, GSMaP shows potential for applications in hydrology, flood forecasting, and meteorology, underscoring its versatility in representing observed rainfall patterns. © 2025

关键词： Bias correction Drought Rainfall measurements Satellite rainfall estimates Siak watershed

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Investigation of factors and their dynamic influences on multi-party collaboration in bim-based prefabricated buildings

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KSCE Journal of Civil engineering 2025年第1期29卷

作者： Luo, Lan Wan, Piao Zhong, Zhiwen Bo, Qiushi Yan, Xueya Chen, Yonghong School of Public Policy and Administration Nanchang University Nanchang330031 China School of Infrastructure Engineering Nanchang University Nanchang330031 China Faculty of Civil Engineering and Mechanics Kunming University of Science and Technology Kunming650500 China

Prefabricated buildings offer numerous benefits such as high-quality construction, energy efficiency, and eco-friendliness. The emergence of building information modeling (BIM) has greatly accelerated the popularization of prefabricated buildings. Nevertheless, the development of BIM-based prefabricated buildings is still immature, requiring the cooperation of multi-parties. How to coordinate the working relationship among multi-parties and improve work efficiency in each stage has become a challenge. In this study, six factors affecting multi-party collaboration in BIM-based prefabricated buildings are identified through a literature review combined with the Delphi method, including information collaboration C1, resource collaboration C2, organization collaboration C3, environment collaboration C4, process collaboration C5, and goal collaboration C6. Then, with the method of fuzzy cognitive map (FCM), a multi-party collaboration FCM model is constructed to explore the dynamic influence of six factors on collaborative efficiency. The results show that (1) six collaborative factors are positively correlated with collaborative efficiency, among which C3 and C6 have the highest positive correlation;(2) when collaborative efficiency changes, C1 and C3 are most affected;and (3) without considering the uncontrollable factors in construction, the collaborative efficiency is most sensitive to the change of C3 and C6. The findings of this study are of great significance in improving the efficiency of multi-party collaboration and ensuring the high-quality construction of BIM-based prefabricated building projects. © 2024

关键词： Fuzzy inference

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Evaluation of effectiveness of polymer coatings in reducing blastinduced deformation of steel plates

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Defence technology（防务技术） 2021年第6期17卷 1895-1904页

作者： Damith Mohotti P.L.N.Fernando Dakshitha Weerasinghe Alex Remennikov School of Engineering and Information Technology The University of New South WalesCanberraACT2600Australia Department of Civil Engineering Faculty of EngineeringGeneral Sir John Kotelawala Defence UniversityRatmalanaSri Lanka School of Civil Engineering Faculty of EngineeringThe University of SydneyDarlingtonNSW2006Australia Centre for Infrastructure Protection and Mining Safety University of WollongongWollongongNSW2522Australia

Incorporating elastomers such as polymers in protective structures to withstand high energetic dynamic loads,has gained significant *** main objective of this study is to investigate the influence of a Polyurea coating towards the blast-induced response in steel *** such,Polyurea coated steel plates were tested under near-field blast loads,produced by the detonation of 1 kg of spherical nitromethane charges,at a standoff distance of 150 *** steel(XLERPLATE 350)and high-strength steel(BIS80)plates with thicknesses of 10 mm were Polyurea coated with thicknesses of 6 mm and 12 mm on either the front(facing the charge)or the back *** deformation profiles were measured using 3D *** simulations were performed using the non-linear finite element code *** strain-dependent behaviour of the steel and Polyurea were represented by Johnson-cook and Money-Rivlin constitutive models,*** numerical models were validated by comparing the plate deflection results obtained from the experiments and were then used in the subsequent parametric study to investigate the optimum thickness of the Polyurea *** results indicate that back face coating contributes towards an approximately 20%reduction in the residual deformation as well as the absence of melting of the Polyurea layer,while the front-face coating can be used a means of providing additional standoff distance to the steel plates.

关键词： Polyurea coating Near-field blast LS-DYNA Plate deformation ALE

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Unlocking Power Transformer Reliability: DGA in Mineral Oil and Natural Esters

Unlocking Power Transformer Reliability: DGA in Mineral Oil ...

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IEEE Students' Conference on Electrical, Electronics and Computer Science (SCEECS)

作者： Sarathkumar D Raymon Antony Raj Srinivasan Murugesan Leo John Baptist Andrews Annamalai Alagappan Sivadasan J Department of Electrical and Electronics Engineering Kongu Engineering College Tamil Nadu India Department of Information Technology Faculty of Engineering and Technology Botho University Gaborone Botswana Department of Network and Infrastructure Management Faculty of Engineering and Technology Botho University Gaborone Botswana Department of Electronics and Communication Engineering PSR Engineering College Sivakasi Tamil Nadu India

The crucial factor in ensuring the reliability of any power transformer lies in thoroughly examining the analysis of dissolved gases (DG). However, there have been instances where the DG of the insulating oil alone has not been sufficient to assess its suitability. This study focuses on a posteriority analysis of the DG for both Mineral Oil (MO) and Natural Ester (NE). The DG analysis (DGA) results of MO and Natural Esters are compared based on the standards outlined in ASTM D3612-02. Key gases, grouped as group 1 (H 2 , CO, and CO 2 ) and group 2 (CH 4 , C 2 H 4 , C 2 H 6 , and C 2 H 2 ), are examined in terms of their retention time to determine the oil's suitability under actual transformer conditions. By segregating and interpreting the data of these Key Gases (KG) groups, a comprehensive understanding of their impact is gained, contributing to a deeper comprehension of the subject - UNDERSTANDING KEY GASES. Throughout the analysis, it is observed that the sum of key gases in both MO and natural esters remains below 1000 ppm, which is the safe limit for combustion. Consequently, the significance of this analysis underscores the importance of monitoring key gas proportions in insulating fluids to ensure transformer safety and performance.

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A Near-Wall Acoustic Wave-Based Localization Method for Broken Wires in a Large Diameter Pccp Using an Fbg Sensor Array

SSRN

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SSRN 2022年

作者： Liu, Xudu Feng, Xin Faculty of Infrastructure Engineering Dalian University of Technology Dalian116024 China

Wire breakage induced by corrosion is the main cause of pipe bursts for prestressed cylinder concrete pipes (PCCPs). The current Rayleigh-based acoustic fiber optic methods can only locate the broken wires in 1D manner with the accuracy of pipe diameter. This paper proposed a three-dimensional localization method of broken wires in large dimeter PCCP. According to the acoustic emission characteristic of broken wires, the near-wall acoustic wave was extracted as wire-breakage sensitive feature, and the monitoring scheme based on an array of fiber Bragg grating (FBG) sensors was proposed by integrating with genetic algorithms. The feasibility of the method was verified by numerical simulations and experimental investigations. The maximum errors of the circumferential angle and longitudinal distance were 2.23° and 0.01 m, respectively, in the model test. The novel approach pertains to monitoring the broken wires in PCCPs at the high-risk and high-consequence zones for risk-informed operation & maintenance management. © 2022, The Authors. All rights reserved.

关键词： Prestressed concrete

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Experimental Study of Structural Vibration Control of 10-Mw Jacket Offshore Wind Turbines Using Tuned Mass Damper Under Wind and Wave Loads

SSRN

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SSRN 2023年

作者： Lu, Dongzhe Wang, Wenhua Li, Xin State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian China Institute of Earthquake Engineering Faculty of Infrastructure Engineering Dalian University of Technology Dalian China

As high slender structures, offshore wind turbines (OWTs) are prone to vibration and deformation under winds and waves. Tuned mass dampers (TMDs) have become among the most promising vibration-mitigation methods owing to their simplicity and practicability. To study the vibration control effect of a TMD on a jacket OWT under winds and waves, we conducted a fully coupled vibration-reduction test using a 1/75 scale test model with and without a TMD. The physical model of the jacket OWT included scaled rotor-nacelle assembly (RNA) and support structure models. For the scaled RNA model, a redesigned blade model was used to ensure the similarity of the aerodynamic thrust loads without modifying the scaled test winds. The drivetrain and pitch-control system models were designed to simulate the operating state of an actual OWT. The support structure model was established based on the hydro-structural elastic similarity. Furthermore, based on the first mode of the scaled OWT model, a TMD model was independently designed and manufactured. A fully coupled vibration control test of a 10 MW jacket OWT under winds and waves was performed, and the vibration suppression performance of the designed TMD model on the structural response of the scaled OWT model was evaluated. © 2023, The Authors. All rights reserved.

关键词： Vibration control

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