CFD modeling to study the effect of particle size on dispersion in 20l explosion chamber: An overview

Mine disasters occur predominantly due to methane or coal dust explosion or a combination of both.Among the top ten worst coal mine disasters in India, nine are due to coal dust explosion. The current paper describes a general overview of the parameters causing dispersion leading to coal dust explosion,and computational fluid dynamics(CFD) simulation study to observe the effects of particle size on dispersion in Indian coal mines. Turbulent kinetic energy(TKE) and velocity vector path of dust-air mixture and dust-free air were simulated to understand their effects on coal dust dispersion. The TKE contours and velocity vector paths for dust-free air were uniform and symmetrical due to resistance-free path available. The TKE contours and velocity vector paths for dust-air mixture shows the asymmetrical distribution of contours, due to entrainment of air with dust particles. Vortices were observed in velocity vector paths which gradually diminish on increment of time sequence. These vortices are dead centres where velocity and coal dust particles concentration are both zero.

Generating A New Shilling Attack for Recommendation Systems

A collaborative filtering-based recommendation system has been an integral part of e-commerce and e-servicing.To keep the recommendation systems reliable,authentic,and superior,the security of these systems is very crucial.Though the existing shilling attack detection methods in collaborative filtering are able to detect the standard attacks,in this paper,we prove that they fail to detect a new or unknown attack.We develop a new attack model,named Obscure attack,with unknown features and observed that it has been successful in biasing the overall top-N list of the target users as intended.The Obscure attack is able to push target items to the top-N list as well as remove the actual rated items from the list.Our proposed attack is more effective at a smaller number of k in top-k similar user as compared to other existing attacks.The effectivity of the proposed attack model is tested on the MovieLens dataset,where various classifiers like SVM,J48,random forest,and naïve Bayes are utilized.

Pattern of injuries due to wild animal attack among patients presenting to the emergency department:A retrospective observational study

Purpose:The human-wildlife conflicts(HWCs)causing nuisances and injuries are becoming a growing public health concern over recent years worldwide.We aimed to study the demographic profile,mode of injury,pattern of injury,and outcome of wild animal attack victims presented to the emergency department.Methods:This retrospective cross-sectional study was conducted in the emergency department of a tertiary-care hospital in Eastern India.Data were retrieved from the medical records from May 2017 to May 2021.Patients of all ages and genders attacked by wild animals and secondary injuries were included in this study.Patients with incomplete data,injuries due to the attack of stray and domestic animals and trauma due to other causes were excluded.Demographic profile,mode of injury,the pattern of injury,injury severity score(ISS),radiological pattern,and outcome were recorded.Statistical analysis with R(version 3.6.1.)was conducted.Results:A total of 411 wild animal attack victims were studied,of which 374(90.9%)were snakebite injuries and 37(9.1%)were wild mammalian(WM)attack injuries.The mean age of WM attack victims was 46 years,and the male-to-female ratio was 4:1.Elephant attack injury(40.5%)was the most common WM attack injury reported.Most WM attacks(43.2%)occurred between 4:00 a.m.to 8:00 a.m.The median ISS was 18.5(13-28),where 54.2%of patients had polytrauma(ISS>15).Elephant attack was associated with a higher ISS,but the difference was not significant compared to other animal types(p=0.2).Blunt trauma was common pattern of injury in the elephant attack injury cases.Lacerations and soft tissue injuries were common patterns in other animal attacks.Among snakebites,neurotoxic was the most common type(55.4%),and lower extremity was the most common site involved.Conclusion:The young male population is the major victim of HWCs;and elephant is the most common animal involved.There is a need to design scientifically sound preventive strategies for HWCs and to strengthen the preparedness in health establishments to manage victims effectively.

Injuries in survivors of elephant attack:Report of three cases

Human-elephant conflict(HEC)in India is becoming a growing health problem causing many fatalities every year.Elephants produce injuries by trampling,stomping,squeezing,tossing in the air,or crushing/targeting the head and chest commonly.The adult elephants are most aggressive in their mating season,leading to maximum incidences of HECs in this period.These attacks are mostly unprovoked,though most HECs are provoked.In this case series,the authors described the injuries sustained by three survivors in a short span of one month due to the sudden and unprovoked elephant attack.All the injuries were mild to moderate in severity and involved the chest in common.Timely rescue and prompt initiation of treatment were pivotal in their survival.The authors also want to create awareness about the mating season of elephants to minimize these unfortunate events in the future.