A comprehensive review of radiation effects on solder alloys and solder joints

In the realm of military and defence applications, exposure to radiation significantly challenges the performance and reliability of solder alloys and joints in electronic systems. This comprehensive review examines radiation-induced effects on solder alloys and solder joints in terms of microstructure and mechanical properties. In this paper, we evaluate the existing literature, including experimental studies and fundamental theory, to provide a comprehensive overview of the behavior of solder materials under radiation. A review of the literature highlights key mechanisms that contribute to radiation-induced changes in the microstructure, such as the formation of intermetallic compounds, grain growth,micro-voids and micro-cracks. Radiation is explored as a factor influencing solder alloy hardness,strength, fatigue and ductility. Moreover, the review addresses the challenges and limitations inherent in studying the effects of radiation on solder materials and offers recommendations for future research. It is crucial to understand radiation-induced effects on solder performance to design robust and radiationresistant electronic systems. A review of radiation effects on solder materials and their applications in electronics serves as a valuable resource for researchers, engineers, and practitioners in that field.

Microstructure transformations and improving wear resistance of austenitic stainless steel additively fabricated by arc-based DED process

In this study, austenitic stainless steel(ASS) was additively fabricated by an arc-based direct energy deposition(DED) technique. Macrostructure, microstructure, mechanical characteristics at different spatial orientations(0°, 90°, and 45°), and wear characteristics were evaluated at the deposited structure top, middle, and bottom regions. Results show that austenite(γ) and delta-ferrite(δ) phases make up most of the microstructure of additively fabricated SS316LSi steel. Within γ matrix, δ phase is dispersed both(within and along) grain boundaries, exhibiting a fine vermicular morphology. The bottom, middle,and top regions of WAAM deposited ASS exhibit similar values to those of wrought SS316L in the tensile and impact test findings. Notably, a drop in hardness values is observed as build height increases. During SEM examinations of fractured surfaces from tensile specimen, closed dimples were observed, indicating good ductility of as-built structure. Wear test findings show signs of mild oxidation and usual adhesive wear. By depositing a mechanically mixed composite layer, an increase in the oxidation percentage was discovered to facilitate healing of worn surfaces. The findings of this study will help in design, production and renovation of products/components that are prone to wear. WAAM-deposited ASS has remarkable strength and ability to withstand impacts;it can be used in the production of armour plates for defence applications, mainly military vehicles and aircraft.

A review of extreme condition effects on solder joint reliability:Understanding failure mechanisms

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.

Post-Traumatic Stress Disorder among Defence and Security Forces in Northern Benin (2023)

Introduction: Post-traumatic stress disorder (PTSD) is defined as “actual exposure to death or the threat of death, serious injury or sexual violence”, either directly or indirectly, resulting in a symptomatic procession of repetition, avoidance, neurovegetative hyperactivity and individualized symptoms, with or without negative cognitive and mood changes. It therefore goes without saying that the defence and security forces constitute a high-risk population in need of attention. Objective: To study post-traumatic stress disorder in defence and security forces in the city of Parakou in 2023. Methods: Descriptive cross-sectional study conducted from December 2022 to July 2023. The study population consisted of active military, republican police and firefighters in the city of Parakou in 2023. Non-proportional stratified sampling was used, given the inaccessibility of the source population size for national security reasons. Post-traumatic stress disorder was assessed using the “post-traumatic stress disorder checklist-5 (PCLS-5) scale. Results: A total of 305 subjects participated in the survey. Males dominated 90.2%. The most represented corps was the Republican Police (41.6%), most of whom were non-commissioned officers (46.6%). The majority count between 11 and 20 years of service (48.9%), with 2 to 5 missions completed (67.5%). The calculated prevalence of post-traumatic stress disorder was 11.8%, based on the post-traumatic stress disorder checklist-5 (PCL-5). Of the 36 respondents with post-traumatic stress disorder, 20 (55.6%) had experienced an armed attack, 25 (69.4%) had witnessed a violent death, 18 (50.0%) had witnessed the agony of a colleague, 15 (41.7%) had been exposed to a fire or explosion, while 26 (72.2%) had been traumatized by physical and/or verbal aggression. 5 (13.9%) had consulted a specialist psychiatrist, while 6 (16.7%) were on medication and 26 (72.2%) used sport as a means of maintaining physical and mental health. Respectively 22 (61.1%) and 21 (58.3%) had definite symptoms of anxiety and depression. Multivariate analysis revealed a significant association between post-traumatic stress disorder and the following variables: total number of children ≤ 2 (p = 0.015), comorbidities such as arterial hypertension (p = 0.007), history of hepatitis (p = 0.017), work accidents (p = 0.016), alcohol dependence (p = 0.004), domestic violence (p = 0.004), psychological violence (p = 0.017) and anxiety disorders (p Conclusion: Defence and security personnel can also be prey to post-traumatic stress disorder (PTSD), which needs to be systematically taken into account when they are subjected to trauma in the course of their duties. Mental health should be an integral part of the periodic medical check-up objectives for defence and security forces throughout the country.

Hypoxia and oxidative stress:The role of the anaerobic gut,the hepatic arterial buffer response and other defence mechanisms of the liver

The liver is considered a vital organ and is the hub for multiple chemical functions,such as intermediary metabolism and the detoxification of ingested toxins,which are essential for the preservation of life,hence,the origin or the word“liver”.The liver has enormous,highly diversified catalytic potential.This enormous catalytic potential generates massive oxidative stress,which is important for the functions of the liver but is detrimental to the viability of the liver.The liver receives approximately 80%of its blood supply from the portal vein,which brings less saturated blood from the gastrointestinal tract.Hepatocytes operate in a relatively hypoxic microenvironment due to this portal inflow.The development of this hypoxic microenvironment of the liver is an important evolutionary adaptation for its detoxification function that is not recognized in the literature as a defence mechanism against the oxidative stress generated during the detoxification process.This review describes liver function in relation to its oxidative catalytic potential and the oxidative stress generated by it as well as the evolutionary defence mechanisms present in the liver against this oxidative stress to provide new insights into liver function.

Role of mucosal dendritic cells in inflammatory bowel disease

The gastrointestinal innate and adaptive immune system continuously faces the challenge of potent stimuli from the commensal microflora and food constituents. These local immune responses require a tight control, the outcome of which is in most cases the induction of tolerance. Local T cell immunity is an important compartment of the specif ic intestinal immune system. T cell reactivity is programmed during the initial stage of its activation by professional presenting cells. Mucosal dendritic cells (DCs) are assumed to play key roles in regulating immune responses in the antigen-rich gastrointestinal environment. Mucosal DCs are a heterogeneous population that can either initiate (innate and adaptive) immune responses, or control intestinal inflammation and maintain tolerance. Defects in this regulation are supposed to lead to the two major forms of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC). This review will discuss the emerging role of mucosal DCs in regulating intestinal inflammation and immune responses.

Response of testicular antioxidant enzymes to hexachlorocy clohexane is species specific

Aim: To find out whether the response of testicular oxidative stress parameters to hexachlorocyclohexane (HCH) is species specific. Methods: In rats and mice (n=5 in each group), HCH was administered at a dose of 20 mg/kg/day intraperitoneally for 30 days in 0.1 ml of refined groundnut oil. The control groups received equal volume of the vehicle. Animals were sacrificed 24 hours after the last injection and various oxidative stress parameters were measured immediately. Results: The level of both endogenous as well as FeSO_4 and ascorbic acid-stimulated lipid peroxidation was increased significantly in the HCH-treated rats, whereas the pattern was just the reverse in case of mice. Although the level of H_2O_2 content increased in response to HCH in both groups, a totally different trend was observed for the activity of the principal H_2O_2-metabolising enzyme, catalase. In case of rats, a significant decline in the activity of catalase was recorded in response to HCH whereas a sharp augmentation in the enzyme activity was noticed in mice. Similarly, the decreased activity of superoxide dismutase observed in rats remained unaltered in mice. Conclusion: HCH induces oxidative stress in the testis of both rats and mice. However, the pattern of response of testicular oxidative stress parameters seems to be species specific.

Recent applications of carbon-based composites in defence industry: A review

Carbon-based composites, including carbon reinforced composites and carbon-matrix composites, in defence technologies have raised a lot of attention due to its significant physical capabilities, superior thermal and mechanical stability, and its eco-friendly nature. Carbon-based composite which incorporating with various carbonaceous materials such as coke, char, black carbon, activated carbon, carbon fibre and other carbon nanomaterials (carbon nanotubes, carbon nanofibres, graphene and graphite) are the greatest viable option for the development of advanced defence technologies. In this review article the characteristics of carbon-based materials and its composites are discussed for their distinct application in defence sectors;aeronautics, maritime, automotive, electronics, energy storage, electromagnetic interference (EMI) shielding and structures. The origin of carbonaceous materials and its production techniques were discussed. Carbon-based composites have a promising future in defence technology, particularly in chemical sensors, drug delivery agents, radar technologies, and nanocomposites due to their low cost, easy availability, flexibility in design and processing.

Protective and defensive roles of non-glandular trichomes against multiple stresses:structure-function coordination

As superficial structures,non-glandular trichomes,protect plant organs against multiple biotic and abiotic stresses.The protective and defensive roles of these epidermal appendages are crucial to developing organs and can be attributed to the excellent combination of suitable structural traits and chemical reinforcement in the form of phenolic compounds,primarily fl avonoids.Both the formation of trichomes and the accumulation of phenolics are interrelated at the molecular level.During the early stages of development,non-glandular trichomes show strong morphological similarities to glandular ones such as the balloon-like apical cells with numerous phenolics.At later developmental stages,and during secondary wall thickening,phenolics are transferred to the cell walls of the trichomes.Due to the diff use deposition of phenolics in the cell walls,trichomes provide protection against UV-B radiation by behaving as optical fi lters,screening out wavelengths that could damage sensitive tissues.Protection from strong visible radiation is also aff orded by increased surface light refl ectance.Moreover,the mixtures of trichome phenolics represent a superfi-cial chemical barrier that provides protection against biotic stress factors such as herbivores and pathogens.Although the cells of some trichomes die at maturity,they can modulate their quantitative and qualitative characteristics during development,depending on the prevailing conditions of the external biotic or abiotic environment.In fact,the structure and chemical constituents of trichomes may change due to the particular light regime,herbivore damage,wounding,water stress,salinity and the presence of heavy metals.Hence,trichomes represent dynamic protective structures that may greatly aff ect the outcome of many plant–environment interactions.

The Arabidopsis homologs of CCR4-associated factor 1 show mRNA deadenylation activity and play a role in plant defence responses

Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 and CCR4- associated factor 1 （CAF1）, two components of the well-characterised protein complex named CCR4-NOT. We report here that AtCAF1a and AtCAF1b, putative Arabidopsis homologs of the yeast CAF1 gene, partially complement the growth defect of the yeast call mutant in the presence of caffeine or at high temperatures. The expression of At-CAF1a and AtCAFlb is induced by multiple stress-related hormones and stimuli. Both AtCAF1a and AtCAFlb show deadenylation activity in vitro and point mutations in the predicted active sites disrupt this activity. T-DNA insertion mutants disrupting the expression of AtCAF1a and/or AtCAF1b are defective in deadenylation of stress-related mRNAs, indicating that the two AtCAF1 proteins are involved in regulated mRNA deadenylation in vivo. Interestingly, the single and double mutants of AtCAF1a and AtCAFlb show reduced expression of pathogenesis-related （PR） genes PR1 and PR2 and are more susceptible to Pseudomonas syringae pv tomato DC3000 （Pst DC3000） infection, whereas transgenic plants over-expressing AtCAFla show elevated expression of PR1 and PR2 and increased resis-tance to the same pathogen. Our results suggest roles of the AtCAF1 proteins in regulated mRNA deadenylation and defence responses to pathogen infections.

A review on lightweight materials for defence applications:Present and future developments

The defence sector is now at an advanced level,catering to the global scenario,and countries also invest heavily in research and development.Countries around the world have spent a lot of money on research and development over the years in order to stay ahead of their competitors.Lightweight materials are critical in defence applications because they allow components to be lighter without sacrificing strength.This review provides an overview of the research related to defence applications.The book provides comprehensive details on current trends in the application of lightweight materials in defence.This review also includes historical and current perspectives on defence technologies.It discusses uses of lightweight materials such as metal matrix composites,polymer composites,ceramic matrix composites,fiber composites in defence sectors Finally,the review paper also emphasizes future military applications of lightweight materials.

Induction of defence gene expression by oligogalacturonic acid requires in-creases in both cytosolic calcium and hydrogen peroxide in Arabidopsis thaliana

Responses to oligogalacturonic acid (OGA) were determined in transgenic Arabidopsis thaliana seedlings expressing the calcium reporter protein aequorin. OGA stimulated a rapid, substantial and transient increase in the concentration of cytosolic calcium ([Ca2+]cyt) that peaked after ca. 15 s. This increase was dose-dependent, saturating at ca. 50 μg Gal equiv/ml of OGA. OGA also stimulated a rapid generation of H2O2. A small, rapid increase in H2O2 content was followed by a much larger oxidative burst, with H2O2 content peaking after ca. 60 min and declining thereafter. Induction of the oxidative burst by OGA was also dose-dependent, with a maximum response again being achieved at ca. 50 μg Gal equiv/mL. Inhibitors of calcium fluxes inhibited both increases in [Ca2+]cyt and [H2O2], whereas inhibitors of NADPH oxidase blocked only the oxidative burst. OGA increased strongly the expression of the defence-related genes CHS,GST, PAL and PR-1. This induction was suppressed by inhibitors of calcium flux or NADPH oxidase, indicating that increases in both cytosolic calcium and H2O2 are required for OGA-induced gene expression.

Security Defence Policy Selection Method Using the Incomplete Information Game Model

Nowadays, the network defence policy selection using game model of incomplete information ignores the type of the defender, which quantifies cost simply, resulting in unreasonable defence policies selection. Aiming at the problem, we use Bayesian game theory to model the active defence policy selection. We take the types of both the attacker and the defender into consideration. Besides, the traditional quantization method is enhanced. Then, we calculate the equilibrium of static Bayesian game. Based on the analysis of the equilibrium, we select the optimal defence policy through the prediction for attackers' actions. The paper calculates the defence effectiveness of defence policies and provides a defence policies selection algorithm. Ultimately, we present an example to verify the effectiveness of the method and model proposed in the paper.

Optimal Active Defence Using Dynamic Multi-Stage Signalling Game

Nowadays, security defence of network uses the game theory, which mostly applies complete information game model or even the static game model. To get closer to the actual network and defend actively, we propose a network attack-defence game model by using signalling game, which is modelled in the way of dynamic and incomplete information. We improve the traditional attack-defence strategies quantization method to meet the needs of the network signalling game model. Moreover, we give the calculation of the game equilibrium and analyse the optimal defence scheme. Finally, we analyse and verify effectiveness of the model and method through a simulation experiment.

Texture evaluation in AZ31/AZ31 multilayer and AZ31/AA5068 laminar composite during accumulative roll bonding

This article presents the texture development of magnesium AZ31 alloy in the accumulative roll bonded(ARB) AZ31/AZ31 multilayer and AZ31/AA5086 laminate composite.The comparative study demonstrates that the texture evolution in AZ31 in a multilayer system is strongly influenced by the interfaces.A typical basal texture of AZ31 has been observed in AZ31/AZ31 multilayer with texture intensity increased with the rolling deformation.Presence of AZ31/AA5086 interface in the laminate composite leads to a tilted basal texture along the rolling direction(RD) in AZ31 alloy.The texture intensity of composite increased initially with rolling reduction and weakened at the higher rolling strain.Weakening of texture in AZ31 during the laminate processing at higher strain has been attributed to the development of wavy interfaces in AZ31/AA5086 laminate.

Overexpression of Toll-like receptor 4 contributes to the internalization and elimination of Escherichia coli in sheep by enhancing caveolae-dependent endocytosis

Background:Gram-negative bacterial infections have a major economic impact on both the livestock industry and public health.Toll-like receptor 4(TLR4)plays a crucial role in host defence against Gram-negative bacteria.Exploring the defence mechanism regulated by TLR4 may provide new targets for treatment of inflammation and control of bacterial infections.In a previous study,we generated transgenic sheep overexpressing TLR4 by microinjection to improve disease resistance.The defence mechanism through which TLR4 overexpression protected these sheep against pathogens is still not fully understood.Results:In the present study,we used Escherichia coli to infect monocytes isolated from peripheral blood of the animal model.The overexpression of TLR4 strongly enhanced the percentage of endocytosis and capacity of elimination in monocytes during the early stages of infection.This phenomenon was mainly due to overexpression of TLR4 promoting caveolae-mediated endocytosis.Pretreatment of the transgenic sheep monocytes with inhibitors of TLR4,Src signalling,or the caveolae-mediated endocytosis pathway reduced the internalization of bacteria,weakened the ability of the monocytes to eliminate the bacteria,and increased the pH of the endosomes.Conclusion:Together,our results reveal the effects of TLR4 on the control of E.coli infection in the innate immunity of sheep and provide crucial evidence of the caveolae-mediated endocytosis pathway required for host resistance to invading bacteria in a large animal model,providing theoretical support for breeding disease resistance in the future.Furthermore,Src and caveolin 1(CAV1)could be potentially valuable targets for the control of infectious diseases.

Sex differences and effects of oestrogen in rat gastric mucosal defence

AIM To evaluate sex differences and the effects of oestrogen administration in rat gastric mucosal defence.METHODS Sex differences in gastric mucus thickness and accumulation rate, absolute gastric mucosal blood flow using microspheres, the integrity of the gastric mucosal epithelium in response to a chemical irritant and the effects of oestrogen administration on relative gastric mucosal blood flow in an acute setting was assessed in an in vivo rat experimental model. Subsequently, sex differences in the distribution of oestrogen receptors and calcitonin gene related peptide in the gastric mucosa of animals exposed to oestrogen in the above experiments was evaluated using immunohistochemistry.RESULTS The absolute blood flow in the GI-tract was generally higher in males, but only significantly different in the corpus part of the stomach (1.12 ± 0.12 m L/min·g in males and 0.51 ± 0.03 m L/min·g in females) (P = 0.002). After removal of the loosely adherent mucus layer the thickness of the firmly adherent mucus layer in males and females was 79 ± 1 μm and 80 ± 3 μm respectively. After 60 min the mucus thickness increased to 113 ± 3 μm in males and 121 ± 3 μm in females with no statistically significant difference seen between the sexes. Following oestrogen administration(0.1 followed by 1 μg/kg·min), mean blood flow in the gastric mucosa decreased by 31% [68 ± 13 perfusion units (PFU)] in males which was significantly different compared to baseline(P = 0.02). In females however, mean blood flow remained largely unchanged with a 4% (5 ± 33 PFU) reduction. The permeability of the gastric mucosa increased to a higher level in females than in males (P = 0.01) after taurocholate challenge. However, the calculated mean clearance increase did not significantly differ between the sexes [0.1 ± 0.04 to 1.1 ± 0.1 m L/min·100 g in males and 0.4 ± 0.3 to 2.1 ± 0.3 m L/min·100 g in females(P = 0.065)]. There were no significant differences between 17β-Estradiol treated males (mean ratio of positive staining ± SEM)(0.06 ± 0.07) and females(0.11 ± 0.11) in the staining of ERα (P = 0.24). Also, there were no significant differences between 17β-Estradiol treated males (0.18 ± 0.21) and females (0.06 ± 0.12) in the staining of ERβ (P = 0.11). Finally, there were no significant differences between 17β-Estradiol treated males (0.04 ± 0.05) and females (0.11 ± 0.10) in the staining of CGRP(P = 0.14).CONCLUSION Gastric mucosal blood flow is higher in male than in female rats and is reduced in male rats by oestrogen administration.

Functional characterization of(E)-β-caryophyllene synthase from lima bean and its up-regulation by spider mites and alamethicin

（E）-β-Caryophyllene is a sesquiterpene compound widely distributed in plants and functions in plant defence. However, little is known about the sequence and function of （E）-β-caryophyllene synthase in lima bean （Phaseolus lunatus）. Here, we report a new full-length cDNA （PICAHS） encoding （E）-β-caryophyllene synthase, a possible key enzyme of plant defence. The cDNA of PICAHS contains an open reading frame of 1 761 bp, encoding a protein of 586 amino acids with a predicted mass of 67.95 kDa. The deduced amino acid sequence shows 52% identity with sesquiterpene synthase MtCAHS of Med- icago truncatula. Based on phylogenetic analysis, PICAHS is classified as the terpene synthases （TPS）-a subfamily. The recombinant enzyme, expressed in Escherichia coil, catalysed the formation of a major product （E）-β-caryophyllene （82%） and a minor product a-humulene （18%） from farnesyl dJphosphate. Real-time quantitative PCR （qRT-PCR） analysis found that the PICAHS transcript was significantly up-regulated in leaves after treatment with spider mites and alamethicin （ALA）, suggesting its ecological function in plant defence.

Protection of armoured vehicles against chemical, biological and radiological contamination

The article presents problems related to mechanical protection of vehicles with different add-on armours against chemical,biological and radiological contamination.This applies to vehicles with additional passive,reactive and hybrid protection in the form of cassettes against piercing with anti-tank projectiles,piercing with their kinetic energy of impact,and as a result of chemical energy of shaped charges as well as explosively formed projectiles.It has been shown how increased ballistic protection of these vehicles at the same time reduces their decontaminability in various places of the vehicle due to the increased additional surface of the vehicle with cassettes.Prevention of contamination of these cassettes has been presented as a way of reducing hard to reach surface for decontamination and a method of insulating construction elements(stands),fixing these cassettes to the vehicle,from the environment to prevent contact with contaminated liquids and dusts.The selection of appropriate materials is shown,which may affect the improvement of the decontamination efficiency of the vehicle with such cassettes.This applies to the use of materials with low absorption of chemical warfare agents,which prevent the accumulation of large amounts of these agents on contaminated surfaces and improve the effectiveness of decontamination.It also shows how to ensure better access of the disinfectant to as much of the vehicle surface as possible,covered with cassettes that have been contaminated.It shows how a vehicle,in particular with such cassettes,can provide protection against radar detection when Radar Absorbent Material is used on vehicle cassettes.

Tidal Forecast for Final Closure of Saemangeum Tidal Dike

The Saemangeum project includes well-developed tidal flats, two estuaries of the Mankyeong and Dongjin rivers, and a chain of small iskands in the outer area off the dike by reclaiming a surface area of 40100 ha. A long sea dike of 30 km has been constructed in the mid-west area of Korea. This paper describes the construction of tidal dikes focusing on the final closure operation performed in April, 2006 employing intermediate technology. Predictive modelling was also carried out to predict the real-time flow fields during the gradual closure operation of the final stage.