Defence Technology(防务技术)最新文献

A novel detection method for warhead fragment targets in optical images under dynamic strong interference environments 动态强干扰环境下光学图像中弹头碎片目标的新型检测方法

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.08.008

Guoyi Zhang , Hongxiang Zhang , Zhihua Shen , Deren Kong , Chenhao Ning , Fei Shang , Xiaohu Zhang

A measurement system for the scattering characteristics of warhead fragments based on high-speed imaging systems offers advantages such as simple deployment, flexible maneuverability, and high spatiotemporal resolution, enabling the acquisition of full-process data of the fragment scattering process. However, mismatches between camera frame rates and target velocities can lead to long motion blur tails of high-speed fragment targets, resulting in low signal-to-noise ratios and rendering conventional detection algorithms ineffective in dynamic strong interference testing environments. In this study, we propose a detection framework centered on dynamic strong interference disturbance signal separation and suppression. We introduce a mixture Gaussian model constrained under a joint spatial-temporal-transform domain Dirichlet process, combined with total variation regularization to achieve disturbance signal suppression. Experimental results demonstrate that the proposed disturbance suppression method can be integrated with certain conventional motion target detection tasks, enabling adaptation to real-world data to a certain extent. Moreover, we provide a specific implementation of this process, which achieves a detection rate close to 100% with an approximate 0% false alarm rate in multiple sets of real target field test data. This research effectively advances the development of the field of damage parameter testing.

基于高速成像系统的弹头碎片散射特性测量系统具有部署简单、机动灵活、时空分辨率高等优点，能够获取碎片散射过程的全过程数据。然而，摄像机帧率与目标速度之间的不匹配会导致高速碎片目标出现较长的运动模糊尾迹，从而导致信噪比较低，使传统的探测算法在动态强干扰测试环境中失效。在本研究中，我们提出了一种以动态强干扰干扰信号分离和抑制为核心的检测框架。我们引入了空间-时间-变换域联合 Dirichlet 过程约束下的混合高斯模型，并结合总变异正则化实现干扰信号抑制。实验结果表明，所提出的干扰抑制方法可以与某些传统的运动目标检测任务相结合，从而在一定程度上适应真实世界的数据。此外，我们还提供了这一过程的具体实现方法，在多组真实目标现场测试数据中实现了接近 100% 的检测率，误报率约为 0%。这项研究有效地推动了损伤参数测试领域的发展。

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引用次数: 0

Discovering causal models for structural, construction and defense-related engineering phenomena 发现结构、建筑和国防相关工程现象的因果模型

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 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.

因果关系是一门关于因果关系的科学，它使我们有可能创建一系列新的模型。这类模型通常被称为因果模型。与那些数学、数值、实证或机器学习（ML）性质的模型不同，因果模型希望通过因果原则将现象（即数据生成过程）的因果关系联系起来。本文是在结构和建筑工程领域创建因果模型的首批作品之一。为此，本文首先简要回顾了因果关系原理，然后采用四种因果关系发现算法，即 PC（彼得-克拉克）、FCI（快速因果推理）、GES（贪婪等价搜索）和 GRaSP（贪婪松弛最稀疏排列），对四种现象进行了研究，包括预测轴向加载构件的承载能力、结构构件的耐火性、梁的抗剪强度和墙体抗冲击（爆炸）荷载能力。研究结果揭示了发现完整和部分因果模型的可能性和优点。最后，本研究还提出了两个有助于评估因果发现算法性能的简单指标。

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引用次数: 0

Study on cook-off characteristics and thermal safety venting area of RBOE charge

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.08.016

Kebin Zhang , Wenbin Li , Changfang Zhao , Zhifang Wei , Shuxia Zhang , Jin Li

RBOE is a new type of DNAN-based high-energy melt-cast mixed explosive, whose safety under thermal stimulation is significantly affected by heating conditions and venting area of the warhead. Based on the thermal decomposition reaction characteristics and combustion characteristics of each component of RBOE explosive, the cook-off calculation models of RBOE warhead before and after ignition were established. In addition, closed and vented warheads were designed, as well as fast and slow cook-off test devices. The cook-off characteristics and thermal safety venting area of RBOE warhead were extensively studied. The results showed that the closed RBOE warhead underwent deflagration reaction under both slow and fast cook-off conditions. The calculation result of the shell wall temperature before slow cook-off ignition response of the warhead was 454.06 K, with an error of +1.75% compared to the test result of 462.15 K, and the temperature rise rate calculated was in good agreement with the test. The calculated ignition time of RBOE warhead under fast cook-off was 161 s, with an error of +8.8% compared to the test result of 148 s, which verified the accuracy of cook-off model of RBOE warhead before ignition. According to the cook-off calculation model of the warhead after ignition and cook-off test of the vented warhead, it was determined that the thermal safety venting area was 1124.61 mm² for fast cook-off and 530.66 mm² for slow cook-off, effectively preventing the reaction of warhead above combustion. Therefore, this study provides a scientific basis for the thermal safety design and evaluation of insensitive warheads.

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引用次数: 0

Critical quality indicators of high-performance polyetherimide (ULTEM) over the MEX 3D printing key generic control parameters: Prospects for personalized equipment in the defense industry 高性能聚醚酰亚胺（ULTEM）对 MEX 3D 打印关键通用控制参数的关键质量指标：国防工业个性化设备的发展前景

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.08.001

Nectarios Vidakis , Markos Petousis , Constantine David , Nektarios K. Nasikas , Dimitrios Sagris , Nikolaos Mountakis , Mariza Spiridaki , Amalia Moutsopoulou , Emmanuel Stratakis

Additive Manufacturing (AM) can provide customized parts that conventional techniques fail to deliver. One important parameter in AM is the quality of the parts, as a result of the material extrusion 3D printing (3D-P) procedure. This can be very important in defense-related applications, where optimum performance needs to be guaranteed. The quality of the Polyetherimide 3D-P specimens was examined by considering six control parameters, namely, infill percentage, layer height, deposition angle, travel speed, nozzle, and bed temperature. The quality indicators were the root mean square (Rq) and average (Ra) roughness, porosity, and the actual to nominal dimensional deviation. The examination was performed with optical profilometry, optical microscopy, and micro-computed tomography scanning. The Taguchi design of experiments was applied, with twenty-five runs, five levels for each control parameter, on five replicas. Two additional confirmation runs were conducted, to ensure reliability. Prediction equations were constructed to express the quality indicators in terms of the control parameters. Three modeling approaches were applied to the experimental data, to compare their efficiency, i.e., Linear Regression Model (LRM), Reduced Quadratic Regression Model, and Quadratic Regression Model (QRM). QRM was the most accurate one, still the differences were not high even considering the simpler LRM model.

快速成型制造（AM）可以提供传统技术无法提供的定制零件。增材制造的一个重要参数是零件的质量，这是材料挤压三维打印（3D-P）程序的结果。这在与国防有关的应用中非常重要，因为这些应用需要保证最佳性能。通过考虑六个控制参数，即填充百分比、层高、沉积角度、移动速度、喷嘴和床层温度，对聚醚酰亚胺 3D-P 试样的质量进行了检测。质量指标包括均方根（q）和平均（a）粗糙度、孔隙率以及实际尺寸与标称尺寸的偏差。检测采用光学轮廓仪、光学显微镜和微型计算机断层扫描。采用田口试验设计法，在五个副本上进行了二十五次试验，每个控制参数分为五个等级。另外还进行了两次确认运行，以确保可靠性。构建了预测方程，用控制参数来表示质量指标。对实验数据采用了三种建模方法来比较其效率，即线性回归模型（LRM）、减二次回归模型和二次回归模型（QRM）。QRM 是最准确的模型，但即使考虑到较简单的 LRM 模型，其差异仍然不大。

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引用次数: 0

Experimental investigation on the anti-detonation performance of composite structure containing foam geopolymer backfill material 含泡沫土工聚合物回填材料的复合结构抗爆性能实验研究

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.08.011

Hang Zhou , Hujun Li , Zhen Wang , Dongming Yan , Wenxin Wang , Guokai Zhang , Zirui Cheng , Song Sun , Mingyang Wang

The compression and energy absorption properties of foam geopolymers increase stress wave attenuation under explosion impacts, reducing the vibration effect on the structure. Explosion tests were conducted using several composite structure models, including a concrete lining structure (CLS) without foam geopolymer and six foam geopolymer composite structures (FGCS) with different backfill parameters, to study the dynamic response and wave dissipation mechanisms of FGCS under explosive loading. Pressure, strain, and vibration responses at different locations were synchronously tested. The damage modes and dynamic responses of different models were compared, and how wave elimination and energy absorption efficiencies were affected by foam geopolymer backfill parameters was analyzed. The results showed that the foam geopolymer absorbed and dissipated the impact energy through continuous compressive deformation under high strain rates and dynamic loading, reducing the strain in the liner structure by 52% and increasing the pressure attenuation rate by 28%. Additionally, the foam geopolymer backfill reduced structural vibration and liner deformation, with the FGCS structure showing 35% less displacement and 70% less acceleration compared to the CLS. The FGCS model with thicker, less dense foam geopolymer backfill, having more pores and higher porosity, demonstrated better compression and energy absorption under dynamic impact, increasing stress wave attenuation efficiency. By analyzing the stress wave propagation and the compression characteristics of the porous medium, it was concluded that the stress transfer ratio of FGCS-ρ-579 was 77% lower than that of CLS, and the transmitted wave energy was 90% lower. The results of this study provide a scientific basis for optimizing underground composite structure interlayer parameters.

泡沫土工聚合物的压缩和吸能特性增加了爆炸冲击下的应力波衰减，降低了对结构的振动影响。利用几种复合结构模型（包括不含泡沫土工聚合物的混凝土衬砌结构（CLS）和六种具有不同回填参数的泡沫土工聚合物复合结构（FGCS））进行了爆炸试验，以研究爆炸荷载下泡沫土工聚合物复合结构的动态响应和消波机制。对不同位置的压力、应变和振动响应进行了同步测试。比较了不同模型的破坏模式和动态响应，分析了泡沫土工聚合物回填参数对消波和能量吸收效率的影响。结果表明，在高应变率和动态加载条件下，泡沫土工聚合物通过连续压缩变形吸收和消散了冲击能量，使衬垫结构的应变降低了 52%，压力衰减率提高了 28%。此外，泡沫土工聚合物回填减少了结构振动和衬垫变形，与 CLS 相比，FGCS 结构的位移减少了 35%，加速度减少了 70%。FGCS 模型的泡沫土工聚合物回填材料更厚、密度更低、孔隙更多和孔隙率更高，在动态冲击下具有更好的压缩和能量吸收能力，提高了应力波衰减效率。通过分析应力波的传播和多孔介质的压缩特性，得出结论：FGCS-ρ-579 的应力传递比比 CLS 低 77%，传递的波能低 90%。该研究结果为优化地下复合结构夹层参数提供了科学依据。

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引用次数: 0

Synergistic effect of nitrocellulose coating on structural and reactivity stabilization of ammonium nitrate oxidizer 硝化纤维素涂层对硝酸铵氧化剂结构和反应活性稳定化的协同效应

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 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 via 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。

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引用次数: 0

Innovative dispersion techniques of graphene nanoplatelets (GNPs) through mechanical stirring and ultrasonication: Impact on morphological, mechanical, and thermal properties of epoxy nanocomposites 通过机械搅拌和超声波处理石墨烯纳米片 (GNP) 的创新分散技术：对环氧纳米复合材料形态、机械和热性能的影响

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.04.018

Vasi Uddin Siddiqui , S.M. Sapuan , Mohd Roshdi Hassan

Graphene nanoplatelets (GNPs) have attracted tremendous interest due to their unique properties and bonding capabilities. This study focuses on the effect of GNP dispersion on the mechanical, thermal, and morphological behavior of GNP/epoxy nanocomposites. This study aims to understand how the dispersion of GNPs affects the properties of epoxy nanocomposite and to identify the best dispersion approach for improving mechanical performance. A solvent mixing technique that includes mechanical stirring and ultrasonication was used for producing the nanocomposites. Fourier transform infrared spectroscopy was used to investigate the interaction between GNPs and the epoxy matrix. The measurements of density and moisture content were used to confirm that GNPs were successfully incorporated into the nanocomposite. The findings showed that GNPs are successfully dispersed in the epoxy matrix by combining mechanical stirring and ultrasonication in a single step, producing well-dispersed nanocomposites with improved mechanical properties. Particularly, the nanocomposites at a low GNP loading of 0.1 wt%, demonstrate superior mechanical strength, as shown by increased tensile properties, including improved Young's modulus (1.86 GPa), strength (57.31 MPa), and elongation at break (4.98). The nanocomposite with 0.25 wt% GNP loading performs better, according to the viscoelastic analysis and flexural properties (113.18 MPa). Except for the nanocomposite with a 0.5 wt% GNP loading, which has a higher thermal breakdown temperature, the thermal characteristics do not significantly alter. The effective dispersion of GNPs in the epoxy matrix and low agglomeration is confirmed by the morphological characterization. The findings help with filler selection and identifying the best dispersion approach, which improves mechanical performance. The effective integration of GNPs and their interaction with the epoxy matrix provides the doorway for additional investigation and the development of sophisticated nanocomposites. In fields like aerospace, automotive, and electronics where higher mechanical performance and functionality are required, GNPs' improved mechanical properties and successful dispersion present exciting potential.

{"title":"Innovative dispersion techniques of graphene nanoplatelets (GNPs) through mechanical stirring and ultrasonication: Impact on morphological, mechanical, and thermal properties of epoxy nanocomposites","authors":"Vasi Uddin Siddiqui , S.M. Sapuan , Mohd Roshdi Hassan","doi":"10.1016/j.dt.2024.04.018","DOIUrl":"10.1016/j.dt.2024.04.018","url":null,"abstract":"<div><div>Graphene nanoplatelets (GNPs) have attracted tremendous interest due to their unique properties and bonding capabilities. This study focuses on the effect of GNP dispersion on the mechanical, thermal, and morphological behavior of GNP/epoxy nanocomposites. This study aims to understand how the dispersion of GNPs affects the properties of epoxy nanocomposite and to identify the best dispersion approach for improving mechanical performance. A solvent mixing technique that includes mechanical stirring and ultrasonication was used for producing the nanocomposites. Fourier transform infrared spectroscopy was used to investigate the interaction between GNPs and the epoxy matrix. The measurements of density and moisture content were used to confirm that GNPs were successfully incorporated into the nanocomposite. The findings showed that GNPs are successfully dispersed in the epoxy matrix by combining mechanical stirring and ultrasonication in a single step, producing well-dispersed nanocomposites with improved mechanical properties. Particularly, the nanocomposites at a low GNP loading of 0.1 wt%, demonstrate superior mechanical strength, as shown by increased tensile properties, including improved Young's modulus (1.86 GPa), strength (57.31 MPa), and elongation at break (4.98). The nanocomposite with 0.25 wt% GNP loading performs better, according to the viscoelastic analysis and flexural properties (113.18 MPa). Except for the nanocomposite with a 0.5 wt% GNP loading, which has a higher thermal breakdown temperature, the thermal characteristics do not significantly alter. The effective dispersion of GNPs in the epoxy matrix and low agglomeration is confirmed by the morphological characterization. The findings help with filler selection and identifying the best dispersion approach, which improves mechanical performance. The effective integration of GNPs and their interaction with the epoxy matrix provides the doorway for additional investigation and the development of sophisticated nanocomposites. In fields like aerospace, automotive, and electronics where higher mechanical performance and functionality are required, GNPs' improved mechanical properties and successful dispersion present exciting potential.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"43 ","pages":"Pages 13-25"},"PeriodicalIF":5.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141050493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Perspectives on additive manufacturing for warhead applications 增材制造在弹头应用中的前景

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.02.010

Hao Xue , Qiang Zhou , Chuan Xiao , Guangyan Huang

According to different damage modes, warheads are roughly divided into three types: fragmentation warheads, shaped charge warheads, and penetrating warheads. Due to limitations in material and structural manufacturing, traditional manufacturing methods make it difficult to fully utilize the damage ability of the warhead. Additive manufacturing (AM) technology can fabricate complex structures, with classified materials composition and customized components, while achieving low cost, high accuracy, and rapid production of the parts. The maturity of AM technology has brought about a new round of revolution in the field of warheads. In this paper, we first review the principles, classifications, and characteristics of different AM technologies. The development trends of AM technologies are pointed out, including multi-material AM technology, hybrid AM technology, and smart AM technology. From our survey, PBF, DED, and EBM technologies are mainly used to manufacture warhead damage elements. FDM and DIW technologies are mainly used to manufacture warhead charges. Then, the research on the application of AM technology in three types of warhead and warhead charges was reviewed and the existing problems and progress of AM technologies in each warhead were analyzed. Finally, we summarized the typical applications and look forward to the application prospects of AM technology in the field of warheads.

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引用次数: 0

Continuous-flow columns packed with zero-valent iron and iron sulfide as a feasible strategy to remediate the persistent contaminant nitroguanidine 用零价铁和硫化铁填料填装的连续流动色谱柱作为补救持久性污染物硝基胍的可行策略

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.06.001

Youngjae Yu , Erika E. Rios-Valenciana , Robert A. Root , Reyes Sierra-Alvarez , Jon Chorover , Jim A. Field

The insensitive munitions compound nitroguanidine (NQ) is used by the U.S. Army to avoid unintended explosions. However, NQ also represents an emerging contaminant whose environmental emissions can cause toxicity toward aquatic organisms, indicating the need for effective remediation strategies. Thus, we investigated the feasibility of treating water contaminated with NQ in continuous-flow columns packed with zero-valent iron (ZVI) or iron sulfide (FeS). Initially, the impact of pH on NQ transformation by ZVI or FeS was evaluated in batch experiments. The pseudo first-order rate constant for NQ transformation (k_{1, NQ}) by ZVI was 8–10 times higher at pH 3.0 compared to pH 5.5 and 7.0, whereas similar k_{1, NQ} values were obtained for FeS at pH 5.5–10.0. Based on these findings, the influent pH fed to the ZVI- and FeS-packed columns was adjusted to 3.0 and 5.5, respectively. Both reactors transformed NQ into nitrosoguanidine (NsoQ). Further transformation of NsoQ by ZVI produced aminoguanidine, guanidine, and cyanamide, whereas NsoQ transformation by FeS produced guanidine, ammonium, and traces of urea. ZVI outperformed FeS as a reactive material to remove NQ. The ZVI-packed column effectively removed NQ below detection even after 45 d of operation (490 pore volumes, PV). In contrast, NQ breakthrough (removal efficiency <85%) was observed after 18 d (180 PV) in the FeS-packed column. The high NQ removal efficiency and long service life of the ZVI-packed column (>490 PV) suggest that the technology is a promising approach for NQ treatment in packed-bed reactors and in situ remediation.

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引用次数: 0

Experimental and numerical simulation of the attenuation effect of blast shock waves in tunnels at different altitudes 不同高度隧道中爆炸冲击波衰减效应的实验和数值模拟

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.07.005

Changjiang Liu , Hujun Li , Zhen Wang , Yong He , Guokai Zhang , Mingyang Wang

Traffic engineering such as tunnels in various altitudinal gradient zone are at risk of accidental explosion, which can damage personnel and equipment. Accurate prediction of the distribution pattern of explosive loads and shock wave propagation process in semi-enclosed structures at various altitude environment is key research focus in the fields of explosion shock and fluid dynamics. The effect of altitude on the propagation of shock waves in tunnels was investigated by conducting explosion test and numerical simulation. Based on the experimental and numerical simulation results, a prediction model for the attenuation of the peak overpressure of tunnel shock waves at different altitudes was established. The results showed that the peak overpressure decreased at the same measurement points in the tunnel entrance under the high altitude condition. In contrast, an increase in altitude accelerated the propagation speed of the shock wave in the tunnel. The average error between the peak shock wave overpressure obtained using the overpressure prediction formula and the measured test data was less than 15%, the average error between the propagation velocity of shock waves predicted values and the test data is less than 10%. The method can effectively predict the overpressure attenuation of blast wave in tunnel at various altitudes.

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引用次数: 0