Effect of Interface Crack and Corner Singularity in Bimaterial System – Experimental and Numerical Investigation

It is of great importance to study behavior of adhesively bonded dissimilar materials as they are widely used in electronic packaging, plastic integrated circuit, welded joints of dissimilar materials, composite materials etc. Due to mechanical loading, cyclic variation in climate or changes in moisture content of ambience leads to high stress at corners or interface, where discontinuities of geometry or material property is present. In this study an attempt has been made to study the behavior of small crack at the interface of aluminum/epoxy bimaterial system. Initially stress intensity factors are estimated experimentally by digital photoelasticity and then compared numerically with a finite element model. Experimentally, ten-step phase shifting technique is used to get isochromatic phase map without ambiguity and later it is unwrapped to get the total fringe order over the model domain. Three fringe photoelasticity technique is also used to get total fringe order. From this information stress intensity factor at interface crack tip is determined using simplified multi-parameter stress field equation of Deng involving over-deterministic least square approach. Numerically stress intensity factors are evaluated by virtual crack closure integral method. Numerically J-integral method is also used for evaluating stress intensity factors for interface crack. We may have to account for the effect of material mismatch as well as temperatute effect at material interfaces. A bimaterial wedge corner can also act as a source for high stress concentration, and it’s singularity is different from crack tip. In the present work, analytically order of singularity is found out for the aluminium/epoxy bimaterial system and using this, stress fields around the corner is predicted. For finding the order of singularity modified stress field equations of Seweryn has been used with appropriate boundary conditions. A linear elastic fracture mechanics frame work is applied for the entire study

Increases in salience of ethnic identity at work: the roles of ethnic assignation and ethnic identification

To better understand how ethnicity is actually experienced within organisations, we examined reported increases in ethnic identity salience at work and responses to such increases. Thirty British black Caribbean graduate employees were interviewed about how and when they experienced their ethnic identity at work. The findings demonstrated that increased salience in ethnic identity was experienced in two key ways: through ‘ethnic assignation’ (a ‘push’ towards ethnic identity) and ‘ethnic identification’ (a ‘pull’ towards ethnic identity). We explore how and when ethnic assignation and ethnic identification occur at work, and their relevance to how workplaces are experienced by this group of minority ethnic employees. The findings suggest the need for further research attention to the dynamic and episodic nature of social identity, including ethnic identity, within organisations, and to the impact of such increases in salience of social identities on behaviour at work

Experimental Study and Optimization of Machining Parameters in Turning of AISI 1040 Steel with Micro-grooved WC Cutting Tools

In dry turning, control over chip formation and the need for the automated machining lead to an advancement in cutting tools. Such concern towards chip breakability is necessary in reducing tool wear, tool tip temperatures and surface roughness of workpiece material. The present study proposes a new development in the traditionally available cutting tools, which acts like a chip breaker. A series of micro-grooves are machined on the rake face of Tungsten carbide (WC) cutting tools using sinker Electric Discharge Machine (EDM). These micro-grooved tools are used to dissolve long continuous chips and heat from the cutting zone in the dry machining of AISI 1040 steel. The results of micro-grooved cutting tools have shown improvement in reducing the tool tip temperatures and surface roughness compared to the conventional cutting tools. The consolidated chip flow phenomenon of plain WC tools is used to decide the location of micro-grooves on the tool rake face. A Taguchi orthogonal array is used to design an experimental layout with minimum number of repetitions in the experiments. Signal-to-noise  ratios and ANOVA is used to understand and identify the significant factors & their level among the input variables on responses.From the results, it is identified that the cutting speed is the most influencing parameter for tool tip temperature at level 1 (i.e. 112 m/min) and surface roughness at level 5 (i.e. 720 m/min)

Emission Characteristics of the Projectile Fragments at Relativistic Energy

A projectile (84^Kr_36) having kinetic energy around 1 A GeV was used to expose NIKFI BR-2 emulsion target. A total of 700 inelastic events are used in the present studies on projectile fragments. The emission angle of the projectile fragments are strongly affected by charge of the other projectile fragments emitted at same time with different emission angle is observed. The angular distribution studies show symmetrical nature for lighter charge projectile fragments. The symmetrical nature decreased with the charge of projectile fragments. At ~4o of emission angle for double charge projectile fragments, the momentum transfer during interaction is similar for various target species of emulsion were observed. We also observed a small but significant amplitude peaks on both side of the big peak for almost all light charge projectile fragments having different delta angle values. It reflects that there are few percent of projectile fragments that are coming from the decay of heavy projectile fragments or any other process.Comment: 32 pages, 17 Figure

Hypothermia for encephalopathy in low-income and middle-income countries: feasibility of whole-body cooling using a low-cost servo-controlled device

Although therapeutic hypothermia (TH) is the standard of care for hypoxic ischaemic encephalopathy in high-income countries, the safety and efficacy of this therapy in low-income and middle-income countries (LMICs) is unknown. We aimed to describe the feasibility of TH using a low-cost servo-controlled cooling device and the short-term outcomes of the cooled babies in LMIC. Design: We recruited babies with moderate or severe hypoxic ischaemic encephalopathy (aged <6 hours) admitted to public sector tertiary neonatal units in India over a 28-month period. We administered whole-body cooling (set core temperature 33.5°C) using a servo-controlled device for 72 hours, followed by passive rewarming. We collected the data on short-term neonatal outcomes prior to hospital discharge. Results: Eighty-two babies were included-61 (74%) had moderate and 21 (26%) had severe encephalopathy. Mean (SD) hypothermia cooling induction time was 1.7 hour (1.5) and the effective cooling time 95% (0.08). The mean (SD) hypothermia induction time was 1.7 hour (1.5 hour), core temperature during cooling was 33.4°C (0.2), rewarming rate was 0.34°C (0.16°C) per hour and the effective cooling time was 95% (8%). Twenty-five (51%) babies had gastric bleeds, 6 (12%) had pulmonary bleeds and 21 (27%) had meconium on delivery. Fifteen (18%) babies died before discharge from hospital. Heart rate more than 120 bpm during cooling (P=0.01) and gastric bleeds (P<0.001) were associated with neonatal mortality. Conclusions: The low-cost servo-controlled cooling device maintained the core temperature well within the target range. Adequately powered clinical trials are required to establish the safety and efficacy of TH in LMICs. Clinical trial registration number: NCT01760629

Transcriptomic profile of adverse neurodevelopmental outcomes after neonatal encephalopathy

A rapid and early diagnostic test to identify the encephalopathic babies at risk of adverse outcome may accelerate the development of neuroprotectants. We examined if a whole blood transcriptomic signature measured soon after birth,predicts adverse neurodevelopmental outcomeeighteenmonths after neonatal encephalopathy.We performed next generation sequencing on whole blood ribonucleic acid obtained within sixhours of birth from the first 47encephalopathic babies recruited to the Hypothermia for Encephalopathy in Low and middle-income countries (HELIX)trial. Two infants with blood culture positive sepsis were excluded, and the data from remaining 45 were analysed. A total of 855genes were significantly differentially expressed between the good and adverse outcome groups, of which RGS1and SMC4 werethe most significant. Biological pathway analysis adjusted for gender, trial randomisation allocation (cooling therapy versus usual care) and estimated blood leukocyte proportions revealed over-representation of genes from pathways related to melatoninand polo-like kinase in babieswith adverse outcome. These preliminary data suggest that transcriptomic profiling may be a promising tool for rapid risk stratification in neonatal encephalopathy. It may provide insights into biological mechanismsand identify novel therapeutic targetsfor neuroprotection

Impact of organised programs on colorectal cancer screening

<p>Abstract</p> <p>Purpose</p> <p>Colorectal cancer (CRC) screening has been shown to decrease CRC mortality. Organised mass screening programs are being implemented in France. Its perception in the general population and by general practitioners is not well known.</p> <p>Methods</p> <p>Two nationwide observational telephone surveys were conducted in early 2005. First among a representative sample of subjects living in France and aged between 50 and 74 years that covered both geographical departments with and without implemented screening services. Second among General Practionners (Gps). Descriptive and multiple logistic regression was carried out.</p> <p>Results</p> <p>Twenty-five percent of the persons(N = 1509) reported having undergone at least one CRC screening, 18% of the 600 interviewed GPs reported recommending a screening test for CRC systematically to their patients aged 50–74 years. The odds ratio (OR) of having undergone a screening test using FOBT was 3.91 (95% CI: 2.49–6.16) for those living in organised departments (referent group living in departments without organised screening), almost twice as high as impact educational level (OR = 2.03; 95% CI: 1.19–3.47).</p> <p>Conclusion</p> <p>CRC screening is improved in geographical departments where it is organised by health authorities. In France, an organised screening programs decrease inequalities for CRC screening.</p

Hypothermia for encephalopathy in low and middle-income countries (HELIX): Study protocol for a randomised controlled trial

BACKGROUND: Therapeutic hypothermia reduces death and disability after moderate or severe neonatal encephalopathy in high-income countries and is used as standard therapy in these settings. However, the safety and efficacy of cooling therapy in low- and middle-income countries (LMICs), where 99% of the disease burden occurs, remains unclear. We will examine whether whole body cooling reduces death or neurodisability at 18-22 months after neonatal encephalopathy, in LMICs. METHODS: We will randomly allocate 408 term or near-term babies (aged ≤ 6 h) with moderate or severe neonatal encephalopathy admitted to public sector neonatal units in LMIC countries (India, Bangladesh or Sri Lanka), to either usual care alone or whole-body cooling with usual care. Babies allocated to the cooling arm will have core body temperature maintained at 33.5 °C using a servo-controlled cooling device for 72 h, followed by re-warming at 0.5 °C per hour. All babies will have detailed infection screening at the time of recruitment and 3 Telsa cerebral magnetic resonance imaging and spectroscopy at 1-2 weeks after birth. Our primary endpoint is death or moderate or severe disability at the age of 18 months. DISCUSSION: Upon completion, HELIX will be the largest cooling trial in neonatal encephalopathy and will provide a definitive answer regarding the safety and efficacy of cooling therapy for neonatal encephalopathy in LMICs. The trial will also provide important data about the influence of co-existent perinatal infection on the efficacy of hypothermic neuroprotection. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02387385. Registered on 27 February 2015