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.

Enhancement of seal life through carbon composite back-up rings under shock loading conditions in defence applications

The life of Nitrile Butadiene Rubber(NBR) O-ring seal having shore hardness of A70 and A90 under shock loading conditions was investigated by a specially designed pneumo-hydraulic shock test rig. Shock tests have been carried out on bare seals, seal with conventional polytetrafluoroethylene(PTFE) back-up rings and seal with newly developed carbon composite back-up rings to study its behaviour under different operating conditions until failure. Experiments were conducted by varying annular gap ranging from 0.3 to 0.5 mm, oil temperature from 30 ℃ to 70 ℃ and rate of pressure rise from 600 to 2400 MPa/s. Significant enhancement in seal life was observed with carbon composite back-up ring at reduced annular clearances compared to seal life with conventional PTFE back-up ring and without back-up rings.

Defence force activities in marine protected areas:environmental management of Shoalwater Bay Training Area,Queensland,Australia

Environmental management of military activities is of growing global concern by defence forces. As one of the largest landholders in Australia, the Australian Defence Force (ADF) is increasingly concerned with sustainable environmental management. This paper focuses on how the ADF is maintaining effective environmental management, especially in environmentally sensitive marine protected areas. It uses Shoalwater Bay Training Area (SWBTA) as a research example to examine environmental management strategies conducted by the ADF. SWBTA is one of the most significant Defence training areas in Australia, with a large number of single, joint and combined military exercises conducted in the area. With its maritime component contained in the Great Barrier Reef Marine Park (GBRMP), the Great Barrier Reef World Heritage Area (GBRWHA), and abutting Queensland’s State Marine Parks, it has high protection values. It is therefore vital for the ADF to adopt environmentally responsible management while they are conducting military activities. As to various tools employed to manage environmental performance, the ISO 14001 Environmental Management System (EMS) is widely used by the ADF. This paper examines military activities and marine environmental management within SWBTA, using the Talisman Saber (TS) exercise series as an example. These are extensive joint exercises conducted by the ADF and the United States defence forces. The paper outlines relevant legislative framework and environmental policies, analyses how the EMS operates in environmental management of military activities, and how military activities comply with these regulations. It discusses the implementation of the ADF EMS, including risk reduction measures, environmental awareness training, consultation and communication with stakeholders. A number of environmental management actions used in the TS exercises are presented to demonstrate the EMS application. Our investigations to this point indicate that the ADF is complying with all relevant legislation and policies. Further research is required to confirm compliance and conclude that military activities have good accord with environmental management objectives.

Prevalence of Flatfoot and Its Correlation with Age,Gender and BMI among Undergraduates at the Faculty of Allied Health Sciences,General Sir John Kotelawela Defence University

Pes planus or flatfeet is a postural deformity which leads the entire sole of the foot to completely or near-completely touch the ground.Pes planus deformity occurs due to collapse of foot arches which can be congenital or pathological.The objective of this study was to determine the prevalence of flatfoot condition among undergraduates at the Faculty of Allied Health Sciences(FAHS),General Sir John Kotelawala Defence University(KDU)and its correlation with age,gender and BMI.A cross sectional study was conducted among 533 participants(Male=131,Female=402).Interviewer-administered questionnaire was used to collect the demographic data.BMI was calculated by obtaining height and weight measurements.Arch index method was used to determine the foot type taken using the Modified Harris Mat.The data analysis was done using SPSS software version 23.P value of less than 0.05 was considered as statistically significant.The study was done among people aged 19 to 26.The prevalence of flatfoot among this age group was 34.7%(n=185).Most of them are bilateral flat feet(73.5%),only 26.5%are unilateral flat feet.The proportion of patients with flat footedness was significantly higher in women(75%)than in men(25%).BMI in the overweight and obese categories(BMI>23)was statistically significant(p<0.05),which is 164(52.4%).Study shows a statistically significant association between flatfoot and increasing BMI beyond normal(p<0.05).There is no significant association between flatfoot with age and gender.Prevalence of flatfoot among allied health undergraduates was seemingly high requiring screening for early detection and appropriate referral for corrective measures.

Advances in Zika virus vaccines and therapeutics:A systematic review

Zika virus(ZIKV)is the causative agent of a viral infection that causes neurological complications in newborns and adults worldwide.Its wide transmission route and alarming spread rates are of great concern to the scientific community.Numerous trials have been conducted to develop treatment options for ZIKV infection.This review highlights the latest developments in the fields of vaccinology and pharmaceuticals developments for ZIKV infection.A systematic and comprehensive approach was used to gather relevant and up-to-date data so that inferences could be made about the gaps in therapeutic development.The results indicate that several therapeutic interventions are being tested against ZIKV infection,such as DNA vaccines,subunit vaccines,live-attenuated vaccines,virus-vector-based vaccines,inactivated vaccines,virus-like particles,and mRNA-based vaccines.In addition,approved anti-ZIKV drugs that can reduce the global burden are discussed.Although many vaccine candidates for ZIKV are at different stages of development,none of them have received Food and Drug Authority approval for use up to now.The issue of side effects associated with these drugs in vulnerable newborns and pregnant women is a major obstacle in the therapeutic pathway.

Coumarin and eugenol ameliorate LPS-induced inflammation in RAW 264.7 cells via modulating the NLRP3 inflammasome pathway

Objective:To investigate the underlying mechanism of anti-inflammatory action of coumarin and eugenol in lipopolysaccharide(LPS)-stimulated RAW 264.7 cells.Methods:RAW 264.7 cells were treated with 2.5μg/mL of LPS,50μM of coumarin,and 50μM eugenol for 24 h.The viability of the cells was assessed using MTT assay.The production of nitric oxide was determined using Griess reagent and DCFH-DA was used to measure the production of reactive oxygen species.The protein expression of NLRP3,IL-1β,NF-κB,and cyclooxygenase 2 was assessed using Western blot analysis.Results:Coumarin and eugenol showed anti-inflammatory effects against LPS-induced inflammatory response by ameliorating the expression of NLRP3 inflammasome and NF-κB,which further led to a subsequent reduction in IL-1β,nitric oxide,and reactive oxygen species.Conclusions:Coumarin and eugenol exert their anti-inflammatory activities by modulating the NLRP3 inflammasome pathway and NF-κB.These compounds may have promising therapeutic applications for the treatment of various inflammatory diseases.

The effect of reactive plasticizer on viscoelastic and mechanical properties of solid rocket propellants based on different types of HTPB resin

Conventional plasticizers deteriorate mechanical and viscoelastic properties of the propellants due to their migration upon aging and long-term storage,which affects reliability and safety properties during exploitation.To address this issue,conventional plasticizer,dioctyl adipate(DOA),is replaced by reactive one,castor oil(CO).In addition,three different types of HTPB were used to obtain propellants with designed viscoelastic and mechanical properties.The CO increased propellants viscosity,without a significant impact on the propellant processability,regardless to the type of prepolymer.Conversely,mechanical properties were different depending on the type of resin,which were further analyzed by gel permeation chromatography(GPC).Addition of CO formed a denser polymer network and shifted T_(g) to higher values,compared to the compositions with DOA.The tensile strength of CO-containing propellants was lower at +20℃ and +50℃ compared to the reference compositions,while the strain at maximum load and strain at break were significantly increased with pronounced plastic deformation,especially for samples at -30℃.The inclusion of CO in the propellants composition gives more room for adjusting a wide range of mechanical properties.

Velocity equation for grenades while impacting on dry sand media

This paper deals with the collision of sphere shape grenades with sand media.The central issue of the article is the establishing of an empirical velocity equation of the grenade while impacting on sand that is used to solve motion equations of the mechanical mechanism inside the impact grenade fuze.The paper focuses on impact velocities that are lower than 5 m s^(-1).An experiment was conducted to study the velocity of the grenade while impacting on dry sand.A high-speed camera video was used to capture the grenade positions.The grenade velocity in the impact process was generated from these video data.Some types of fitting curves are used to regress the velocity equation of the grenade while interacting with the sand media and the best-fitting model is chosen.The result shows the regression curve has a high correlation with the experiment data for grenade velocities below 5 m s^(-1).The received regression equation is useful for analyzing the working ability of the inertial mechanism inside the impact grenade or analyzing and choosing the appropriate parameters of each part in the inertial mechanism to meet the required characteristics of the mechanism.

Treatment of uveitis and scleritis patients in Malaysia

●AIM:To determine the common causes and visual outcome after treatment among uveitis and scleritis patients.●METHODS:This is a retrospective cohort observational study.All consecutive clinical records of patients with newly diagnosed uveitis and scleritis over a 4-year period,from Jan.1,2017 to Dec.31,2020,were analysed.Data was collected at the presentation and included a follow-up period of one year.●RESULTS:A total of 288 patients were recruited during the study period.Anterior uveitis was the most common anatomical diagnosis(50.0%)followed by panuveitis(25.0%),scleritis(13.5%),posterior uveitis(6.9%),and intermediate uveitis(4.5%).Viral Herpes was the most common cause of infectious cases,while Vogt-Koyanagi-Harada(VKH)disease and human leucocyte antigen(HLA)B27 spondyloarthropathy were the leading causes of identifiable non-infectious cases.Majority of patients presented with unilateral,non-granulomatous uveitis with an absence of hypopyon.Anatomical locations like posterior uveitis and panuveitis,and visual acuity worse than 3/60 at presentation were the factors associated with poor visual outcomes(P<0.05).About 60%of patients had an identifiable cause for the uveitis and scleritis,with nearly equal distribution of infectious(n=85,29.5%)and noninfectious causes(n=84,29.2%).About 14.5%of patients were clinically blind at 1y of follow-up.The most common complication in our uveitis patients was glaucoma(47.5%),followed by cystoid macula oedema(18.9%)and cataract(13.9%).●CONCLUSION:Uveitis and scleritis are important causes of ocular morbidity.They are potentially blinding diseases which can have a good outcome if diagnosed and treated early.

Study of relationship between motion of mechanisms in gas operated weapon and its shock absorber

The article deals with the motion of the breech block carrier and the weapon casing of an automatic weapon mounted on a flexible carriage and the base of the weapon.Earlier works,which did not consider the dynamic properties of the base of the weapon,did not allow to reconcile the calculated and experimental results of the weapon casing displacement when shooting from firing rests.For the analysis of the motion of individual parts,the methods of mathematical modelling and firing experiments using a high-speed camera were chosen.Calculations show the best accord with experiment when modelling the system with 4 degrees of freedom.The oscillation of the system regarding the movement of the breech block carrier and the weapon casing was investigated under changed conditions of rate of fire,the use of a muzzle brake and different types of shock absorbers.The velocities and displacements of the weapon casing and the breech block carrier at different values of the impulse of the gases to the breech block carrier were determined.

Target acquisition performance in the presence of JPEG image compression

This paper presents an investigation on the effect of JPEG compression on the similarity between the target image and the background,where the similarity is further used to determine the degree of clutter in the image.Four new clutter metrics based on image quality assessment are introduced,among which the Haar wavelet-based perceptual similarity index,known as HaarPSI,provides the best target acquisition prediction results.It is shown that the similarity between the target and the background at the boundary between visually lossless and visually lossy compression does not change significantly compared to the case when an uncompressed image is used.In future work,through subjective tests,it is necessary to check whether this presence of compression at the threshold of just noticeable differences will affect the human target acquisition performance.Similarity values are compared with the results of subjective tests of the well-known target Search_2 database,where the degree of agreement between objective and subjective scores,measured through linear correlation,reached a value of 90%.

Neoadjuvant treatment of pancreatic ductal adenocarcinoma:Whom,when and how

Pancreatic ductal adenocarcinoma(PDAC),which is notorious for its aggressiveness and poor prognosis,remains an area of great unmet medical need,with a 5-year survival rate of 10%-the lowest of all solid tumours.At diagnosis,only 20%of patients have resectable pancreatic cancer(RPC)or borderline RPC(BRPC)disease,while 80%of patients have unresectable tumours that are locally advanced pancreatic cancer(LAPC)or have distant metastases.Nearly 60%of patients who undergo upfront surgery for RPC are unable to receive adequate adjuvant chemotherapy(CHT)because of postoperative complications and early cancer recurrence.An important paradigm shift to achieve better outcomes has been the sequence of therapy,with neoadjuvant CHT preceding surgery.Three surgical stages have emerged for the preoperative assessment of nonmetastatic pancreatic cancers:RPC,BRPC,and LAPC.The main goal of neoadjuvant treatment(NAT)is to improve postoperative outcomes through enhanced selection of candidates for curative-intent surgery by identifying patients with aggressive or metastatic disease during initial CHT,reducing tumour volume before surgery to improve the rate of margin-negative resection(R0 resection,a microscopic margin-negative resection),reducing the rate of positive lymph node occurrence at surgery,providing early treatment of occult micrometastatic disease,and assessing tumour chemosensitivity and tolerance to treatment as potential surgical criteria.In this editorial,we summarize evidence concerning NAT of PDAC,providing insights into future practice and study design.Future research is needed to establish predictive biomarkers,measures of therapeutic response,and multidisciplinary stra tegies to improve patient-centered outcomes.

Enhancing the clinical relevance of haemorrhage prediction models in trauma

We read with interest the recent systematic reviewaArtificial intelligence and machine learning for hemorrhagic trauma careoby Peng et al.[1],which evaluated literature on machine learning(ML)in the management of traumatic haemorrhage.We thank the authors for their contribution to the role of ML in trauma.

Parameter-Free Shifted Laplacian Reconstruction for Multiple Kernel Clustering

Dear Editor,This letter proposes a parameter-free multiple kernel clustering(MKC)method by using shifted Laplacian reconstruction.Traditional MKC can effectively cluster nonlinear data,but it faces two main challenges:1)As an unsupervised method,it is up against parameter problems which makes the parameters intractable to tune and is unfeasible in real-life applications;2)Only considers the clustering information,but ignores the interference of noise within Laplacian.

Evolutionary fingerprint, phylogenetic and forest structure of tropical montane Atlantic cloud forests along an elevation gradient

Environmental conditions can change markedly over geographical distances along elevation gradients,making them natural laboratories to study the processes that structure communities.This work aimed to assess the influences of elevation on Tropical Montane Cloud Forest plant communities in the Brazilian Atlantic Forest,a historically neglected ecoregion.We evaluated the phylogenetic structure,forest structure(tree basal area and tree density)and species richness along an elevation gradient,as well as the evolutionary fingerprints of elevation-success on phylogenetic lineages from the tree communities.To do so,we assessed nine communities along an elevation gradient from 1210 to 2310 m a.s.l.without large elevation gaps.The relationships between elevation and phylogenetic structure,forest structure and species richness were investigated through Linear Models.The occurrence of evolutionary fingerprint on phylogenetic lineages was investigated by quantifying the extent of phylogenetic signal of elevation-success using a genus-level molecular phylogeny.Our results showed decreased species richness at higher elevations and independence between forest structure,phylogenetic structure and elevation.We also verified that there is a phylogenetic signal associated with elevation-success by lineages.We concluded that the elevation is associated with species richness and the occurrence of phylogenetic lineages in the tree communities evaluated in Mantiqueira Range.On the other hand,elevation is not associated with forest structure or phylogenetic structure.Furthermore,closely related taxa tend to have their higher ecological success in similar elevations.Finally,we highlight the fragility of the tropical montane cloud forests in the Mantiqueira Range in face of environmental changes(i.e.global warming)due to the occurrence of exclusive phylogenetic lineages evolutionarily adapted to environmental conditions(i.e.minimum temperature)associated with each elevation range.

Feature extraction and learning approaches for cancellable biometrics:A survey

Biometric recognition is a widely used technology for user authentication.In the application of this technology,biometric security and recognition accuracy are two important issues that should be considered.In terms of biometric security,cancellable biometrics is an effective technique for protecting biometric data.Regarding recognition accuracy,feature representation plays a significant role in the performance and reliability of cancellable biometric systems.How to design good feature representations for cancellable biometrics is a challenging topic that has attracted a great deal of attention from the computer vision community,especially from researchers of cancellable biometrics.Feature extraction and learning in cancellable biometrics is to find suitable feature representations with a view to achieving satisfactory recognition performance,while the privacy of biometric data is protected.This survey informs the progress,trend and challenges of feature extraction and learning for cancellable biometrics,thus shedding light on the latest developments and future research of this area.

A Cross-Sectional Study on the Impact of Operation Triple Zero (OTZ) Program on Viral Load Suppression amongst Members of the Adolescent Club in 68 Nigerian Army Reference Hospital Yaba Lagos, Nigeria

Background: In Nigeria, adolescents and young people (AYP) aged 10 - 24, comprise 22.3% of the population and with HIV prevalence of 3.5%. The AYP living with HIV enrolled at the 68 NARHY, Lagos reflects the national challenges with poor viral suppression. The OTZ program aligns with the UNAIDS 95-95-95 goals. It seeks to empower AYPLHIV to be in charge of their treatment and commit to triple zero outcomeszero missed appointments, zero missed drugs, and zero viral loads. The purpose of the study was to assess the impact of the OTZ program on viral load suppression among members of the adolescent club in 68 NARHY, Lagos. Method: A cross-sectional retrospective study to evaluate the impact of the OTZ program on the viral load of 53 AYP enrolled in the OTZ program between March 2019 to December 2019 was analyzed. The Percentage of viral load suppression before enrollment compared with 6 and 12 months after enrollment into the OTZ program. The AYP is grouped into 10 - 14, 15 - 19, and 20 - 24 years. Activities conducted were peer driven monthly meetings with the AYP during which the adolescents interacted on issues relating to improving their treatment outcomes, healthcare workers reviewed their clinical status, viral load result, provider peer counseling, and caregivers engagement to support adherence to medication and ARV refills. Results: Before OTZ, 81% aged 10 - 14 years, 75% aged 15 - 19 years, and 25% aged 20 - 24 years were virally suppressed (VL less than 1000 copies/ml). Six months after enrollment, 94% were virally suppressed95% aged 10 - 14 years, 96% aged 15 - 19 years, and 66% aged 20-24 years. Twelve months after enrollment, 96% of AYP were virally suppressed100% aged 10-14 years, 93% aged 15 - 19 years, and 100% aged 20 - 24 years. Males viral load (VL) suppression improved from 79% to 96% and 92%, while females VL suppression improved from 69% to 93% and 100% at 6 and 12 months respectively. Conclusion: The OTZ activities contributed to improved viral load suppression in the AYP of the facility.

First-Principles Investigation of Charge Transfer Mechanism of B-Doped 3C-SiC Semiconductor Material

This study delves into the charge transfer mechanism of boron (B)-doped 3C-SiC through first-principles investigations. We explore the effects of B doping on the electronic properties of 3C-SiC, focusing on a 12.5% impurity concentration. Our comprehensive analysis encompasses structural properties, electronic band structures, and charge density distributions. The optimized lattice constant and band gap energy of 3C-SiC were found to be 4.373 Å and 1.36 eV respectively, which is in agreement with previous research (Bui, 2012;Muchiri et al., 2018). Our results show that B doping narrows the band gap, enhances electrical conductivity, and influences charge transfer interactions. The charge density analysis reveals substantial interactions between B dopants and surrounding carbon atoms. This work not only enhances our understanding of the material’s electronic properties, but also highlights the importance of charge density analysis for characterizing charge transfer mechanisms and their implications in the 3C-SiC semiconductors.

Artificial intelligence and machine learning for hemorrhagic trauma care

Artificial intelligence(AI),a branch of machine learning(ML)has been increasingly employed in the research of trauma in various aspects.Hemorrhage is the most common cause of trauma-related death.To better elucidate the current role of AI and contribute to future development of ML in trauma care,we conducted a review focused on the use of ML in the diagnosis or treatment strategy of traumatic hemorrhage.A literature search was carried out on PubMed and Google scholar.Titles and abstracts were screened and,if deemed appropriate,the full articles were reviewed.We included 89 studies in the review.These studies could be grouped into five areas:(1)prediction of outcomes;(2)risk assessment and injury severity for triage;(3)prediction of transfusions;(4)detection of hemorrhage;and(5)prediction of coagulopathy.Performance analysis of ML in comparison with current standards for trauma care showed that most studies demonstrated the benefits of ML models.However,most studies were retrospective,focused on prediction of mortality,and development of patient outcome scoring systems.Few studies performed model assessment via test datasets obtained from different sources.Prediction models for transfusions and coagulopathy have been developed,but none is in widespread use.AI-enabled ML-driven technology is becoming integral part of the whole course of trauma care.Comparison and application of ML algorithms using different datasets from initial training,testing and validation in prospective and randomized controlled trials are warranted for provision of decision support for individualized patient care as far forward as possible.