Interfacial Mechanical Strength Characterization in Multilayered Materials via Nanoscale Impact and Nano Mechanical Raman Spectroscopy Experiments

A composite materials strength can significantly depend on the constitutive description of interfaces. A computational model of composite deformation should, therefore, incorporate interface constitutive behavior. These interfaces poses several challenges in studying them due their length scales of micrometer to nanometer as well the coupling of other factors such as confinement during the loading. Thus, separating main phase constitutive behavior from interface constitutive behavior in mechanical property measurement experiments is an arduous task. In this work, an epoxy interface between glass plates is analyzed under quasistatic and dynamic loading conditions to obtain a description of interfacial constitutive response at strain rates from 10-2 to 103 s-1. The experiments were conducted with indenters of radius 1, 10 and 100 µm on the interfaces thicknesses of 1, 10 and 100 µms within the spatial error tolerance of less than 3 µms. The interface thickness was verified with the Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis. The approach relies on describing interfaces as a confined material phase between two unconfined phases. Dynamic microscale impact tests are used to obtain stress-strain response as a function of strain rate for the analyzed interfaces. The data was then subjected to statistical analysis to remove experimental errors. An analytical model was developed to find the confinement effect and the solution was verified by capturing stress maps with Nanomechanical Raman Spectroscopy (NRS) experiments pre and post experiments to analyze the change in the stress distribution around interfaces. Based on the analyses of confinement effects, a constitutive model is proposed to predict the interface deformation behavior with a dependence on both strain rate and confinement effect. This model is further used in the finite element simulations to predict and quantify the role of interfaces in multilayered materials

Investigation into the environment and temperature dependent nanomechanical properties of the shallow water shrimp - (Penaeus spp.) exoskeleton

This investigation focuses on understanding the influence of change in wet to dry environment and change in temperature from room temperature to 80°C on nanomechanical properties of fresh water shrimp exoskeleton. Scanning electron microscopy based measurements suggest that the shrimp exoskeleton has the Bouligand structure in its layers, a key characteristic of the crustaceans. The thickness of the layers and packing density is found to be different than that of lobsters and crabs reported earlier in the literature. As expected, the wet samples are found to be softer than dry samples. The reduced modulus values of dry samples are found to be around 26 GPa as compared to be ~5 GPa in the case of wet samples. Similarly the hardness values are found to be ~1 GPa in the case of dry samples as compared to the corresponding values being ~0.2 GPa in the case of wet samples. In order to simulate the influence of underwater pressure on the exoskeleton strength, constant load creep experiments as a function of wet and dry environment are performed. Effect of increased temperature on the properties is also analyzed in terms of creep mechanisms. Both reduced modulus and hardness values show a decrease with increase in the temperature. The reduced modulus values are found to be around 28 GPa at 30°C that reduces to ~24 GPa at 80°C. The hardness values also decrease from 1.6 GPa at 30°C to ~1.2 GPa at 80°C. The switch in deformation mechanism as function of environment is explained based on the role played by water molecules in assisting interface slip and increased ductility of matrix material in the fiber/matrix and deformation

Prevalence and Genotypes of Mycobacterium Avium Subspecies Paratuberculosis in Large Ruminants of Eastern Uttar Pradesh, North India

Uttar Pradesh is the fourth largest, most populous and leading milk and meat producing state in India. Despite the huge livestock population, information on the status of paratuberculosis homogeneity and heterogeneity of Mycobacterium avium subspecies paratuberculosis (MAP) isolates of eastern Uttar Pradesh is non-existent. Present study was aimed to estimate the presence of MAP in large ruminants (Cattle and Buffaloes) of eastern Uttar Pradesh. A total 108 fecal samples were collected from farmer's herds of large ruminants (cattle and buffaloes) from different geographical regions (Chandauli, Mughalsarai, Gazipur, and Naugarh) of eastern Uttar Pradesh and screened for the presence of MAP infection using microscopic examination, direct IS900 PCR and culture on Herrold egg yolk (HEY) medium. The isolates recovered on HEY medium were subjected to molecular identification and genotyping using IS900 PCR and IS1311 PCR-REA method, respectively. Of the 108 fecal samples, 25 (23.14%) and 11 (10.18%) samples were positive for the presence of acid-fast bacilli and growth on HEY medium, respectively. Species-wise, 17.5, 7.5% and 26.5, 11.7% fecal samples from cattle and buffaloes were found positive for the presence of acid-fast bacilli and growth on HEY medium, respectively. Isolates recovered on HEY medium with mycobactin J were positive for IS900 sequence and genotyped as Bison Type using IS1311 PCR-REA method. Present study is the first report on the presence of MAP infection and ‘Bison Type' genotype of MAP in eastern Uttar Pradesh. These findings will be useful for the intervention of effective control measures in order to reduce the prevalence of MAP infection in domestic livestock species and prevent its spread to the human population in the regions

A Study on the Antagonistic Action of some Bacterial isolates against some common Soil Fungi

Three bacterial species (bbrd sp., bprd sp., bsrd sp.) and five fungal species (frd1 sp., ard2 sp., prd3 sp., rrd4 sp. and trd5 sp.) were isolated from the soil sample collected from various place of garden of School of Environmental Science and agricultural field near B.B.A. University, Lucknow, India. Basic aim of the isolation of fungi and bacteria was to evaluate the antifungal capacity of some bacterial species. Bacterial species inhibit the growth of fungi by the process of antagonium. Antagonism is the phenomenon in which one microorganism destroys the other interacting partner to ensure its own survival. Three bacterial stains bbrd sp., bprd sp., bsrd sp. showed to be excellent producers of antifungal metabolites. The present data exhibit the antifungal activity of the bacterial strain indicate the possibility to use it as biological agents against some plant’s pathogenic fungi by the antimicrobial activity of the microbial metabolites. Antagonistic interaction between microbes were studied by the measurement of the zone of inhibition on agar plate, that allow for repeated observation of numerous sites and inhibition with a minimum disturbance of the cells and soil particles

A Study on the Antagonistic Action of some Bacterial isolates against some common Soil Fungi

Three bacterial species (bbrd sp., bprd sp., bsrd sp.) and five fungal species (frd1 sp., ard2 sp., prd3 sp., rrd4 sp. and trd5 sp.) were isolated from the soil sample collected from various place of garden of School of Environmental Science and agricultural field near B.B.A. University, Lucknow, India. Basic aim of the isolation of fungi and bacteria was to evaluate the antifungal capacity of some bacterial species. Bacterial species inhibit the growth of fungi by the process of antagonium. Antagonism is the phenomenon in which one microorganism destroys the other interacting partner to ensure its own survival. Three bacterial stains bbrd sp., bprd sp., bsrd sp. showed to be excellent producers of antifungal metabolites. The present data exhibit the antifungal activity of the bacterial strain indicate the possibility to use it as biological agents against some plant’s pathogenic fungi by the antimicrobial activity of the microbial metabolites. Antagonistic interaction between microbes were studied by the measurement of the zone of inhibition on agar plate, that allow for repeated observation of numerous sites and inhibition with a minimum disturbance of the cells and soil particles

To Improve Quality and Reduce Rejection Level through Quality Control

Organization now a days need to improve their product/process/services continuously and progressively for that lean six sigma is the holistic approach that address multiple aspect of organization competitiveness it is only tool to achieve overall operational excellence.CNC Cutting involves various processes which include machine setting, blade speed, machine parameter, clamping, cooling, etc. It is very difficult to produce defect free cutting. Occurrence of the defect may involve single or multiple causes. These causes can be minimized through systematic procedure of applying various tools and technique .This paper represents analyses and investigation of cutting defects and identification of remedial measures carried out at specific industry. Diagnostic study carried out on overall process of cutting. Cutting products revealed that the contribution of the five prominent defects in cutting rejections were found and they are taper cutting, over size, under size, rough surface and burr. It was noticed that these defects were frequently occurring at different locations. Systematic analyses were carried out to understand the reasons for defects occurrence and suitable remedial measures were identified and implementation of process

Perioperative Haemostatic Management in a Patient Undergoing Craniotomy for Excision of Meningioma: Role of Thromboelastography

Although there is a general predisposition towards hyper-coagulability during brain tumour surgery, hypocoagulability may exist in certain cases even before surgery, detectable only when the physical characteristics of clot formation are studied by viscoelastic point-of-care tests like thromboelastography (TEG). Herein we present a case of a 66-year old male patient with left frontal convexity meningioma, scheduled for craniotomy and excision of tumor. Patient’s preoperative coagulation profile (as assessed by conventional tests) was within normal limits but he was bleeding profusely from the beginning of the surgery and there was massive bleeding during tumour resection. Based on findings of TEG which revealed a severe hypocoagulable picture (low α angle, MA value and CI value with high K value), 10 units of cryoprecipitate and 4 units of random donor platelets were transfused intra-operatively in addition to 2 units of PRBCs.Haemodynamic stability was achieved and subsequent intra-operative course was better. One more unit of PRBC was transfused in the immediate post-operative period and a repeat TEG after 4 hours showed a trend towards normalization of TEG parameters suggesting a restoration of coagulation competency which also correlated with improved clinical condition of the patient

Micro-fabrication of Carbon Structures by Pattern Miniaturization in Resorcinol-Formaldehyde Gel

A simple and novel method to fabricate and miniaturize surface and sub-surface micro-structures and micro-patterns in glassy carbon is proposed and demonstrated. An aqueous resorcinol-formaldehyde (RF) sol is employed for micro-molding of the master-pattern to be replicated, followed by controlled drying and pyrolysis of the gel to reproduce an isotropically shrunk replica in carbon. The miniaturized version of the master-pattern thus replicated in carbon is about one order of magnitude smaller than original master by repeating three times the above cycle of molding and drying. The micro-fabrication method proposed will greatly enhance the toolbox for a facile fabrication of a variety of Carbon-MEMS and C-microfluidic devices.Comment: 16 pages, 5 figure

QCA and CMOS Nanotechnology Based Design and Development of Nanoelectronic Security Devices with Encryption Schemes

In WiMAX/WiFi Wireless Environment the Transfer of Data/Information is vulnerable to external attacks as it takes place through an open-air medium. The Data/Information is vulnerable to Jamming, Detection, Interception, Network Injection, Interruption, Modification, Packet Scrambling, Fabrication, Unauthorised forwarding and Denial-of-Service (DoS). Our Research Work focuses on ‘QCA & CMOS Nanotechnology based Design & Development of Nanoelectronic Security Devices with Encryption Schemes to provide/enhance Security and Privacy for WiMAX/WiFi/Satellite Wireless Communication Systems. The Schemes are based on Dynamic Channel Hopping, Random Channel Selection, Cryptography and Encryption of Information/Data/Control Codes. DOI: http://dx.doi.org/10.11591/telkomnika.v14i2.748

Synthesis, characterization and applications of chitosan based metallic nanoparticles: A review

Chitosan as a natural biopolymer has been produced to be the important host for the preparation of metallic nanoparticles (MNPs) because of its excellent characteristics like:- good stabilizing and capping ability, biocompatibility, biodegradability, eco-friendly and non-toxicity properties. Chitosan can play a very important role for synthesis of metallic nanoparticles, as chitosan is a cationic polymer. It attracts metal ions and reduces them and also Capps and stabilizes. So basically chitosan can be responsible for the controlled synthesis of metallic nanoparticle. Chitosan has a very good chelating property. This property is due to its –NH2 and –OH functional groups. Size and shape of metallic nanoparticles are much affected by chitosan concentration, molecular weight, time of reaction, degree of acetylation of chitosan, pH of the medium, method of synthesis and type of derivative of chitosan etc. Metallic nanoparticles`s properties and applications are much associated with their size and shape. Optimization of the metallic nanoparticle size and shape has been the subject of curiosity for nanotechnology scientist. Chitosan can solve this problem by applying the optimization conditions. But a very little work is reported about: - how chitosan can affect the size and shape of metallic nanoparticles and how can it reduce metal salts to prepare metallic nanoparticle, stablilized in chitosan metrics. This is very first report as a review article highlighting the effect of chitosan on synthesis of metallic nanoparticles and optimization conditions. This review will also be beneficial for scientist working on food sensing application of nanoparticles.  Various synthesis methods and applications of chitosan based metallic nanoparticles have also been reported in details