Pub Date : 2024-05-30DOI: 10.1016/j.dt.2024.05.015
G. Murali, Anoop Kallamalayil Nassar, Madhumitha Swaminathan, Parthiban Kathirvel, Leong Sing Wong
Solid waste recycling is an economically sound strategy for preserving the environment, safeguarding natural resources, and diminishing the reliance on raw material consumption. Geopolymer technology offers a significant advantage by enabling the reuse and recycling of diverse materials. This research assesses how including silica fume and glass powder enhances the impact resistance of ultra-high-performance geopolymer concrete (UHPGC). In total, 18 distinct mixtures were formulated by substituting ground granulated blast furnace slag with varying proportions of silica fume and glass powder, ranging from 10% to 40%. Similarly, for each of the mixtures above, steel fibre was added at a dosage of 1.5% to address the inherent brittleness of UHPGC. The mixtures were activated by combining sodium hydroxide and sodium silicate solution to generate geopolymer binders. The specimens were subjected to drop-weight impact testing, wherein an examination was carried out to evaluate various parameters, including flowability, density at fresh and hardened state, compressive strength, impact numbers indicative of cracking and failure occurrences, ductility index, and analysis of failure modes. Additionally, the variations in the impact test outcomes were analyzed using the Weibull distribution, and the findings corresponding to survival probability were offered. Furthermore, the microstructure of UHPGC was scrutinized through scanning electron microscopy. Findings reveal that the specimens incorporating glass powder exhibited lower cracking impact number values than those utilizing silica fume, with reductions ranging from 18.63% to 34.31%. Similarly, failure impact number values decreased from 8.26% to 28.46% across glass powder contents. The maximum compressive and impact strength was recorded in UHPGC, comprising 10% silica fume with fibres.
{"title":"Effect of silica fume and glass powder for enhanced impact resistance in GGBFS-based ultra high-performance geopolymer fibrous concrete: An experimental and statistical analysis","authors":"G. Murali, Anoop Kallamalayil Nassar, Madhumitha Swaminathan, Parthiban Kathirvel, Leong Sing Wong","doi":"10.1016/j.dt.2024.05.015","DOIUrl":"https://doi.org/10.1016/j.dt.2024.05.015","url":null,"abstract":"Solid waste recycling is an economically sound strategy for preserving the environment, safeguarding natural resources, and diminishing the reliance on raw material consumption. Geopolymer technology offers a significant advantage by enabling the reuse and recycling of diverse materials. This research assesses how including silica fume and glass powder enhances the impact resistance of ultra-high-performance geopolymer concrete (UHPGC). In total, 18 distinct mixtures were formulated by substituting ground granulated blast furnace slag with varying proportions of silica fume and glass powder, ranging from 10% to 40%. Similarly, for each of the mixtures above, steel fibre was added at a dosage of 1.5% to address the inherent brittleness of UHPGC. The mixtures were activated by combining sodium hydroxide and sodium silicate solution to generate geopolymer binders. The specimens were subjected to drop-weight impact testing, wherein an examination was carried out to evaluate various parameters, including flowability, density at fresh and hardened state, compressive strength, impact numbers indicative of cracking and failure occurrences, ductility index, and analysis of failure modes. Additionally, the variations in the impact test outcomes were analyzed using the Weibull distribution, and the findings corresponding to survival probability were offered. Furthermore, the microstructure of UHPGC was scrutinized through scanning electron microscopy. Findings reveal that the specimens incorporating glass powder exhibited lower cracking impact number values than those utilizing silica fume, with reductions ranging from 18.63% to 34.31%. Similarly, failure impact number values decreased from 8.26% to 28.46% across glass powder contents. The maximum compressive and impact strength was recorded in UHPGC, comprising 10% silica fume with fibres.","PeriodicalId":10986,"journal":{"name":"Defence Technology","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141508136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-28DOI: 10.1016/j.dt.2024.05.013
Norliza Ismail, Wan Yusmawati Wan Yusoff, Azuraida Amat, Nor Azlian Abdul Manaf, Nurazlin Ahmad
Solder joint, crucial component in electronic systems, face significant challenges when exposed to extreme conditions during applications. The solder joint reliability involving microstructure and mechanical properties will be affected by extreme conditions. Understanding the behaviour of solder joints under extreme conditions is vital to determine the durability and reliability of solder joint. This review paper aims to comprehensively explore the underlying failure mechanism affecting solder joint reliability under extreme conditions. This study covers an in-depth analysis of effect extreme temperature, mechanical stress, and radiation conditions towards solder joint. Impact of each condition to the microstructure including solder matrix and intermetallic compound layer, and mechanical properties such as fatigue, shear strength, creep, and hardness was thoroughly discussed. The failure mechanisms were illustrated in graphical diagrams to ensure clarity and understanding. Furthermore, the paper highlighted mitigation strategies that enhancing solder joint reliability under challenging operating conditions. The findings offer valuable guidance for researchers, engineers, and practitioners involved in electronics, engineering, and related fields, fostering advancements in solder joint reliability and performance.
{"title":"A review of extreme condition effects on solder joint reliability: Understanding failure mechanisms","authors":"Norliza Ismail, Wan Yusmawati Wan Yusoff, Azuraida Amat, Nor Azlian Abdul Manaf, Nurazlin Ahmad","doi":"10.1016/j.dt.2024.05.013","DOIUrl":"https://doi.org/10.1016/j.dt.2024.05.013","url":null,"abstract":"Solder joint, crucial component in electronic systems, face significant challenges when exposed to extreme conditions during applications. The solder joint reliability involving microstructure and mechanical properties will be affected by extreme conditions. Understanding the behaviour of solder joints under extreme conditions is vital to determine the durability and reliability of solder joint. This review paper aims to comprehensively explore the underlying failure mechanism affecting solder joint reliability under extreme conditions. This study covers an in-depth analysis of effect extreme temperature, mechanical stress, and radiation conditions towards solder joint. Impact of each condition to the microstructure including solder matrix and intermetallic compound layer, and mechanical properties such as fatigue, shear strength, creep, and hardness was thoroughly discussed. The failure mechanisms were illustrated in graphical diagrams to ensure clarity and understanding. Furthermore, the paper highlighted mitigation strategies that enhancing solder joint reliability under challenging operating conditions. The findings offer valuable guidance for researchers, engineers, and practitioners involved in electronics, engineering, and related fields, fostering advancements in solder joint reliability and performance.","PeriodicalId":10986,"journal":{"name":"Defence Technology","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141508323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-30DOI: 10.1016/j.dt.2024.04.017
Amir Abdelaziz, Djalal Trache, Ahmed Fouzi Tarchoun, Hani Boukeciat, Yash Pal, Sourbh Thakur, Weiqiang Pang, Thomas M. Klapötke
The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate (AN) particles utilizing a microencapsulation technique, which involves solvent/non-solvent in which nitrocellulose (NC) has been employed as a coating agent. The SEM micrographs revealed distinct features of both pure AN and NC, contrasting with the irregular granular surface topography of the coated AN particles, demonstrating the adherence of NC on the AN surface. Structural analysis infrared spectroscopy (IR) demonstrated a successful association of AN and NC, with slight shifts observed in IR bands indicating interfacial interactions. Powder X-ray Diffraction (PXRD) analysis further elucidated the structural changes induced by the coating process, revealing that the NC coating altered the crystallization pattern of its pure form. Thermal analysis demonstrates distinct profiles for pure and coated AN, for which the coated sample exhibits a temperature increase and an enthalpy decrease of the room temperature allotropic transition by 6 °C, and 36%, respectively. Furthermore, the presence of NC coating alters the intermolecular forces within the composite system, leading to a reduction in melting enthalpy of coated AN by ∼39% compared to pure AN. The thermal decomposition analysis shows a two-step thermolysis process for coated AN, with a significant increase in the released heat by about 78% accompanied by an increase in the activation barrier of NC and AN thermolysis, demonstrating a stabilized reactivity of the AN-NC particles. These findings highlight the synergistic effect of NC coating on AN particles, which contributed to a structural and reactive stabilization of both AN and NC, proving the potential application of NC-coated AN as a strategically advantageous oxidizer in composite solid propellant formulations.
本研究旨在利用微胶囊技术稳定硝酸铵（AN）颗粒的室温各向同性转变，该技术涉及溶剂/非溶剂，其中采用硝化纤维素（NC）作为涂层剂。扫描电镜显微照片显示了纯 AN 和 NC 的明显特征，与涂覆 AN 颗粒的不规则颗粒表面形貌形成鲜明对比，表明 NC 附着在 AN 表面。红外光谱（IR）结构分析表明 AN 和 NC 成功地结合在一起，观察到的红外波段有轻微偏移，表明存在界面相互作用。粉末 X 射线衍射 (PXRD) 分析进一步阐明了涂层过程引起的结构变化，显示出 NC 涂层改变了其纯形式的结晶模式。热分析显示了纯 AN 和涂层 AN 的不同曲线，其中涂层样品的室温各向同性转变温度和焓值分别提高了 6 ℃ 和降低了 36%。此外，NC 涂层的存在改变了复合体系内的分子间作用力，导致涂层 AN 的熔化焓比纯 AN 降低了 39%。热分解分析表明，包覆 AN 的热分解过程分为两步，释放的热量显著增加了约 78%，同时 NC 和 AN 的热分解活化势垒也有所提高，这表明 AN-NC 颗粒的反应活性趋于稳定。这些发现凸显了数控涂层对 AN 粒子的协同效应，有助于 AN 和数控的结构和反应稳定化，证明了数控涂层 AN 作为一种具有战略优势的氧化剂在复合固体推进剂配方中的潜在应用。
{"title":"Synergistic effect of nitrocellulose coating on structural and reactivity stabilization of ammonium nitrate oxidizer","authors":"Amir Abdelaziz, Djalal Trache, Ahmed Fouzi Tarchoun, Hani Boukeciat, Yash Pal, Sourbh Thakur, Weiqiang Pang, Thomas M. Klapötke","doi":"10.1016/j.dt.2024.04.017","DOIUrl":"https://doi.org/10.1016/j.dt.2024.04.017","url":null,"abstract":"The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate (AN) particles utilizing a microencapsulation technique, which involves solvent/non-solvent in which nitrocellulose (NC) has been employed as a coating agent. The SEM micrographs revealed distinct features of both pure AN and NC, contrasting with the irregular granular surface topography of the coated AN particles, demonstrating the adherence of NC on the AN surface. Structural analysis infrared spectroscopy (IR) demonstrated a successful association of AN and NC, with slight shifts observed in IR bands indicating interfacial interactions. Powder X-ray Diffraction (PXRD) analysis further elucidated the structural changes induced by the coating process, revealing that the NC coating altered the crystallization pattern of its pure form. Thermal analysis demonstrates distinct profiles for pure and coated AN, for which the coated sample exhibits a temperature increase and an enthalpy decrease of the room temperature allotropic transition by 6 °C, and 36%, respectively. Furthermore, the presence of NC coating alters the intermolecular forces within the composite system, leading to a reduction in melting enthalpy of coated AN by ∼39% compared to pure AN. The thermal decomposition analysis shows a two-step thermolysis process for coated AN, with a significant increase in the released heat by about 78% accompanied by an increase in the activation barrier of NC and AN thermolysis, demonstrating a stabilized reactivity of the AN-NC particles. These findings highlight the synergistic effect of NC coating on AN particles, which contributed to a structural and reactive stabilization of both AN and NC, proving the potential application of NC-coated AN as a strategically advantageous oxidizer in composite solid propellant formulations.","PeriodicalId":10986,"journal":{"name":"Defence Technology","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-27DOI: 10.1016/j.dt.2024.04.007
M.Z. Naser
Causality, the science of cause and effect, has made it possible to create a new family of models. Such models are often referred to as causal models. Unlike those of mathematical, numerical, empirical, or machine learning (ML) nature, causal models hope to tie the cause(s) to the effect(s) pertaining to a phenomenon (i.e., data generating process) through causal principles. This paper presents one of the first works at creating causal models in the area of structural and construction engineering. To this end, this paper starts with a brief review of the principles of causality and then adopts four causal discovery algorithms, namely, PC (Peter-Clark), FCI (fast causal inference), GES (greedy equivalence search), and GRaSP (greedy relaxation of the sparsest permutation), have been used to examine four phenomena, including predicting the load-bearing capacity of axially loaded members, fire resistance of structural members, shear strength of beams, and resistance of walls against impulsive (blast) loading. Findings from this study reveal the possibility and merit of discovering complete and partial causal models. Finally, this study also proposes two simple metrics that can help assess the performance of causal discovery algorithms.
{"title":"Discovering causal models for structural, construction and defense-related engineering phenomena","authors":"M.Z. Naser","doi":"10.1016/j.dt.2024.04.007","DOIUrl":"https://doi.org/10.1016/j.dt.2024.04.007","url":null,"abstract":"Causality, the science of cause and effect, has made it possible to create a new family of models. Such models are often referred to as causal models. Unlike those of mathematical, numerical, empirical, or machine learning (ML) nature, causal models hope to tie the cause(s) to the effect(s) pertaining to a phenomenon (i.e., data generating process) through causal principles. This paper presents one of the first works at creating causal models in the area of structural and construction engineering. To this end, this paper starts with a brief review of the principles of causality and then adopts four causal discovery algorithms, namely, PC (Peter-Clark), FCI (fast causal inference), GES (greedy equivalence search), and GRaSP (greedy relaxation of the sparsest permutation), have been used to examine four phenomena, including predicting the load-bearing capacity of axially loaded members, fire resistance of structural members, shear strength of beams, and resistance of walls against impulsive (blast) loading. Findings from this study reveal the possibility and merit of discovering complete and partial causal models. Finally, this study also proposes two simple metrics that can help assess the performance of causal discovery algorithms.","PeriodicalId":10986,"journal":{"name":"Defence Technology","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-22DOI: 10.1016/j.dt.2023.12.005
Ya Yang, Xiangzhen Kong, Qin Fang
Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage. However, stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast load. To investigate this interesting phenomenon, a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov method. The difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress enhancement. The difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads, stress–strain relation and length of foam concrete are considered. In particular, the concept of minimum thickness of foam concrete to avoid stress enhancement is proposed. Finally, non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data, which can provide a reference for the application of foam concrete in defense engineering.
{"title":"Non-dimensional analysis on blast wave propagation in foam concrete: Minimum thickness to avoid stress enhancement","authors":"Ya Yang, Xiangzhen Kong, Qin Fang","doi":"10.1016/j.dt.2023.12.005","DOIUrl":"https://doi.org/10.1016/j.dt.2023.12.005","url":null,"abstract":"<p>Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage. However, stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast load. To investigate this interesting phenomenon, a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov method. The difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress enhancement. The difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads, stress–strain relation and length of foam concrete are considered. In particular, the concept of minimum thickness of foam concrete to avoid stress enhancement is proposed. Finally, non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data, which can provide a reference for the application of foam concrete in defense engineering.</p>","PeriodicalId":10986,"journal":{"name":"Defence Technology","volume":null,"pages":null},"PeriodicalIF":5.1,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139029879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1134/S106345412302005X
M. Ermakov, D. Kapatsa
{"title":"On Uniform Consistency of Neyman’s Type Nonparametric Tests","authors":"M. Ermakov, D. Kapatsa","doi":"10.1134/S106345412302005X","DOIUrl":"https://doi.org/10.1134/S106345412302005X","url":null,"abstract":"","PeriodicalId":10986,"journal":{"name":"Defence Technology","volume":null,"pages":null},"PeriodicalIF":0.2,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75888247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.1016/j.dt.2023.02.025
S. Siengchin
{"title":"A review on lightweight materials for defence applications: A present and future developments","authors":"S. Siengchin","doi":"10.1016/j.dt.2023.02.025","DOIUrl":"https://doi.org/10.1016/j.dt.2023.02.025","url":null,"abstract":"","PeriodicalId":10986,"journal":{"name":"Defence Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42159345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1016/j.dt.2023.02.008
Wenhuan Wang, Bin Wang, Jun Fan, Fulin Zhou, K. Zhao, Zhou Jiang
{"title":"A simulation method on target strength and circular SAS imaging of X-rudder UUV including multiple acoustic scattering","authors":"Wenhuan Wang, Bin Wang, Jun Fan, Fulin Zhou, K. Zhao, Zhou Jiang","doi":"10.1016/j.dt.2023.02.008","DOIUrl":"https://doi.org/10.1016/j.dt.2023.02.008","url":null,"abstract":"","PeriodicalId":10986,"journal":{"name":"Defence Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54060552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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