•A transition mode between conduction and keyhole is utilized for defect free welding of Zr-2.5 wt.% Nb alloy.•Significant change in microstructural morphology across the different weld zones is ...observed.•The residual stress in fusion and heat affected zones is found to be tensile in nature compared to the base metal.•The hardness is found to be changed significantly across different weld zones as result of microstructural modification.•The tensile strength of as welded Zr-2.5 wt.Nb alloy is found to higher than the base metal with poor ductility.
In the present study, Zr-2.5 wt.%Nb alloy plates of thickness 4 mm have been welded using pulsed Nd:YAG laser system at different process parameters and characterized in terms of microstructural evolution, hardness, residual stress, and mechanical properties. It has been observed that heat input plays an important role on mode of welding. The full penetration up to a thickness of 4 mm of the alloy has been achieved at a minimum laser heat input of 800 J mm−1 without any crack and porosity formation. For avoiding the porosity formation in the weld zones, a transition mode between conduction and keyhole has been used by optimizing laser process parameters. The microstructural analysis revealed that the fusion (FZ) is consists of predominant lath type α′ martensitic phase with small amount of randomly distributed acicular type of α′ martensite phase. However, the heat affected zone (HAZ) have lath type α′ martensitic phase together with αZr phase. Further, in the FZ and HAZ regions, the presence of retained βZr phase is higher as compared to the base metal (BM). The change in microstructure and phase field of different weld zones has been explained by evaluating the time-temperature profiles and cooling rates using COMSOL multi-physics simulation. In addition, the FZ and HAZ zones have been found to have tensile residual stress of the order of 280 MPa and 145 MPa as compared to the BM (-70 MPa). The microhardness in the FZ region has been observed to be higher (240–260 HV0.1) as compared to the BM (∼185 HV0.1) due to the formation of martensitic phase. The tensile room temperature testing showed that the mechanical strength of as welded sample is significantly higher than the base metal with lower ductility. The fractography of the fractured surfaces confirmed ductile nature of failure in the as welded samples.
Metal Organic Frameworks (MOFs), a class of crystalline microporous materials have been into research limelight lately due to their commendable physio-chemical properties and easy fabrication ...methods. They have enormous surface area which can be a working ground for innumerable molecule adhesions and site for potential sensor matrices. Their biocompatibility makes them valuable for in vitro detection systems but a compromised conductivity requires a lot of surface engineering of these molecules for their usage in electrochemical biosensors. However, they are not just restricted to a single type of transduction system rather can also be modified to achieve feat as optical (colorimetry, luminescence) and electro-luminescent biosensors. This review emphasizes on recent advancements in the area of MOF-based biosensors with focus on various MOF synthesis methods and their general properties along with selective attention to electrochemical, optical and opto-electrochemical hybrid biosensors. It also summarizes MOF-based biosensors for monitoring free radicals, metal ions, small molecules, macromolecules and cells in a wide range of real matrices. Extensive tables have been included for understanding recent trends in the field of MOF-composite probe fabrication. The article sums up the future scope of these materials in the field of biosensors and enlightens the reader with recent trends for future research scope.
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•MOFs as electrochemical and optical transducers in clinical perspective have been discussed.•An overview of MOFs, their properties and various synthetic routes have been provided.•Alteration in MOF properties through employment of different synthesis routes has been discussed.•Surface engineered MOF-based probes for extensive biomolecular sensing have been elaborated.
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•Effect of laser power density on microstructure and wear properties of laser borided Inconel 718 is studied.•The borided layer is consisting of borides of Ni, Cr and Fe together with ...γ (Ni-Cr-Fe) matrix phase.•Formation of boride phases leads to the significant improvement in hardness (∼5 times) and wear resistance (∼8 times).•In the borided layer, microstructural morphology is changed from cellular to equiaxed dendrites.•The phase stability of borided layer is discussed based on phase equilibria information and thermo-kinetic theory.
Effect of laser power density (LPD) on microstructure and tribological properties of laser borided Inconel 718 is studied. Boriding is carried out using laser powder bed fusion based additive manufacturing process at three LPDs of 17.0, 22.6 and 28.3 kW cm−2. Laser power density played significant role on surface roughness, homogeneity and depth of the borided layer. Higher laser power density led to lower surface roughness, improved homogeneity and higher depth of borided layer. Structural, chemical and microstructural characterization of the borided layer confirmed the formation of Nickel boride (Ni2B/Ni3B), Chromium boride (CrB/Cr2B) and Iron boride (FeB/Fe2B) along with the matrix γ (Ni-Cr-Fe) phase in borided layer. The content of γ phase in borided layer is found to be increased with increase in LPD due to dilution effect. The presence of different boride phases in the borided layer caused significant improvement in hardness (∼5 times) and wear resistance (∼8 times) than the substrate Inconel 718 for LPD of 17.0 kW cm−2. At higher LPD, due to increased content of soft γ phase, both hardness and wear resistance are reduced. Across the borided layer, microstructural morphology is changed from cellular to equiaxed dendrite with a clear columnar to equiaxed transition. The formation of different boride phases and microstructural evolution in the borided layer is discussed in view of available phase equilibria information of Ni-Cr-Fe-B system and thermo-kinetic theory. The findings of present study will be helpful in developing the Ni baser super alloys with improved tribological properties for advanced technological applications under extreme service conditions.
Present study attempts to project extreme precipitation indices over 34 different meteorological subdivisions and six homogeneous regions such as Northwest, Central Northeast, Northeast, West ...Central, Peninsular India and Hilly Region during summer monsoon season in the twenty-first century. For this purpose, the Regional Climate Model version4 (RegCM4) had been run at 50 km horizontal resolution forced with the global model GFDL-ESM2 M, during reference period 1976–2005 for the model validation, and the mid- (2031–2060) and far-future (2070–2099) for projections under RCP8.5 scenario over the South Asia CORDEX domain. In this paper, model simulated precipitation has been validated against IMD, APHRODITE and NCEP/NCAR data sets. The results indicate that RegCM4 captures the important features of seasonal precipitation and various extreme indices over the study area. The RegCM4 has projected an increase in the mean seasonal precipitation by 0.56 mm/day whereas in case of GFDL model the rate is 0.39 mm/day during the far-future relative to the reference period. The heavy precipitation indices are projected to increase more frequently (0.264/decade) than the mean precipitation rate (0.01/decade) over India. The correlations between the extreme precipitation indices and the seasonal mean precipitation are found to be strong. In addition, the consecutive dry days are projected to occur more frequently (3–5 days) over West Central (Telangana, Vidarbha and Marathwada) and west Rajasthan while consecutive wet days are projected to decrease over larger parts of India during far-future. Similarly, 1 day maximum precipitation and the simple daily intensity index are projected to increase consistently from mid- to far- futures over some sub-divisions of West coast, Hilly and Northeast regions. From a spatial probability perspective, model projection indicates more frequent severe drought and flood conditions over India.
Research over the last decade on emerging trace organic contaminants in aquatic systems has largely focused on sources such as treated wastewaters in high income countries, with relatively few ...studies relating to wastewater sources of these contaminants in low and middle income countries. We undertook a longitudinal survey of the Ahar River for a number of emerging organic contaminants (including pharmaceuticals, hormones, personal care products and industrial chemicals) which flows through the city of Udaipur, India. Udaipur is a city of approximately 450,000 people with no wastewater treatment occurring at the time of this survey. We found the concentrations of many of the contaminants within the river water were similar to those commonly reported in untreated wastewater in high income countries. For example, concentrations of pharmaceuticals, such as carbamazepine, antibiotics and non-steroidal anti-inflammatory drugs, ranged up to 1900 ng/L. Other organic contaminants, such as steroid estrogens (up to 124 ng/L), steroid androgens (up to 1560 ng/L), benzotriazoles (up to 11 μg/L), DEET (up to 390 ng/L), BPA (up to 300 ng/L) and caffeine (up to 37.5 μg/L), were all similar to previously reported concentrations in wastewaters in high income countries. An assessment of the population densities in the watersheds feeding into the river showed increasing population density of a watershed led to a corresponding downstream increase in the concentrations of the organic contaminants, with quantifiable concentrations still present up to 10 km downstream of the areas directly adjacent to the highest population densities. Overall, this study highlights how a relatively clean river can be contaminated by untreated wastewater released from an urban centre.
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•Emerging contaminants were detected in a longitudinal survey of a small Indian city’s river receiving untreated wastewater.•Minimal attenuation of contaminants beyond city limits indicated the river is largely composed of untreated wastewater.•A wastewater treatment facility would substantially reduce most contaminant loads within the receiving environment.
Background: Inflammatory bowel disease (IBD) has a typical onset during the peak reproductive years. Evidence of the risk of adverse pregnancy outcomes in IBD is important for the management of ...pregnancy to assist in its management. Aim: To provide a clear assessment of risk of adverse outcomes during pregnancy in women with IBD. Design: The Medline literature was searched to identify studies reporting outcomes of pregnancy in patients with IBD. Random-effect meta-analysis was used to compare outcomes between women with IBD and normal controls. Patients and setting: A total of 3907 patients with IBD (Crohn’s disease 1952 (63%), ulcerative colitis 1113 (36%)) and 320 531 controls were reported in 12 studies that satisfied the inclusion criteria. Results: For women with IBD, there was a 1.87-fold increase in incidence of prematurity (<37 weeks gestation; 95% CI 1.52 to 2.31; p<0.001) compared with controls. The incidence of low birth weight (<2500 g) was over twice that of normal controls (95% CI 1.38 to 3.19; p<0.001). Women with IBD were 1.5 times more likely to undergo caesarean section (95% CI 1.26 to 1.79; p<0.001), and the risk of congenital abnormalities was found to be 2.37-fold increased (95% CI 1.47 to 3.82; p<0.001). Conclusion: The study has shown a higher incidence of adverse pregnancy outcomes in patients with IBD. Further studies are required to clarify which women are at higher risk, as this was not determined in the present study. This has an effect on the management of patients with IBD during pregnancy, who should be treated as a potentially high-risk group.
Er3+-doped tellurite glass containing silver nanoparticles (NPs) has been synthesized. Detailed structural and optical characterizations have been carried out. Infrared to visible frequency ...upconversion (UC) emission has been observed in Er3+-doped tellurite glass on pumping with the 976nm radiation. Further, an enhancement in UC emission intensity of green bands of Er3+ ion has been observed up to four times in presence of silver NPs in the glass annealed at 240 degree C for 40h. Though, there is enhancement in intensity in the red band also but it is smaller. The enhancement in fluorescence intensity is attributed to local field effect due to the silver NPs. Display Omitted
The Global Burden of Diseases, Injuries, and Risk Factors (GBD) Study 2015 provides an up-to-date analysis of the burden of lower respiratory tract infections (LRIs) in 195 countries. This study ...assesses cases, deaths, and aetiologies spanning the past 25 years and shows how the burden of LRI has changed in people of all ages.
We estimated LRI mortality by age, sex, geography, and year using a modelling platform shared across most causes of death in the GBD 2015 study called the Cause of Death Ensemble model. We modelled LRI morbidity, including incidence and prevalence, using a meta-regression platform called DisMod-MR. We estimated aetiologies for LRI using two different counterfactual approaches, the first for viral pathogens, which incorporates the aetiology-specific risk of LRI and the prevalence of the aetiology in LRI episodes, and the second for bacterial pathogens, which uses a vaccine-probe approach. We used the Socio-demographic Index, which is a summary indicator derived from measures of income per capita, educational attainment, and fertility, to assess trends in LRI-related mortality. The two leading risk factors for LRI disability-adjusted life-years (DALYs), childhood undernutrition and air pollution, were used in a decomposition analysis to establish the relative contribution of changes in LRI DALYs.
In 2015, we estimated that LRIs caused 2·74 million deaths (95% uncertainty interval UI 2·50 million to 2·86 million) and 103·0 million DALYs (95% UI 96·1 million to 109·1 million). LRIs have a disproportionate effect on children younger than 5 years, responsible for 704 000 deaths (95% UI 651 000–763 000) and 60.6 million DALYs (95ÙI 56·0–65·6). Between 2005 and 2015, the number of deaths due to LRI decreased by 36·9% (95% UI 31·6 to 42·0) in children younger than 5 years, and by 3·2% (95% UI −0·4 to 6·9) in all ages. Pneumococcal pneumonia caused 55·4% of LRI deaths in all ages, totalling 1 517 388 deaths (95% UI 857 940–2 183 791). Between 2005 and 2015, improvements in air pollution exposure were responsible for a 4·3% reduction in LRI DALYs and improvements in childhood undernutrition were responsible for an 8·9% reduction.
LRIs are the leading infectious cause of death and the fifth-leading cause of death overall; they are the second-leading cause of DALYs. At the global level, the burden of LRIs has decreased dramatically in the last 10 years in children younger than 5 years, although the burden in people older than 70 years has increased in many regions. LRI remains a largely preventable disease and cause of death, and continued efforts to decrease indoor and ambient air pollution, improve childhood nutrition, and scale up the use of the pneumococcal conjugate vaccine in children and adults will be essential in reducing the global burden of LRI.
Bill & Melinda Gates Foundation.
•Nannochloropsis sp. illustrates high capacity of biodiesel production.•FA profile and lipid productivity credited alga as an excellent energy resource.•Nannochloropsis sp. exhibited terrific ...tolerance against arsenic at 100μM As(III).•Nannochloropsis sp. accumulated maximum 2019.04μg/gdw As.
The present study was conducted with microalga Nannochloropsis sp. to evaluate its tolerance responses and biofuel perspectives under different arsenic regime (0–1000μM As(III)). Results showed that optimal biomass (61.00±3.72mg/L/d) and lipid productivity (20.27mg/L/d) were obtained in culture treated with 100μM As(III) in comparison to other treatments. In addition, fatty acid profile of alga was in accordance with European biodiesel standards (EN 14214), which reflects good oxidative stability of oil. High antioxidants viz., ascorbic acid, GSH and cysteine tolerance responses as well as lipid yield at 100μM As(III), opens a new insight in the field of algal biology. Thus, microalgae Nannochloropsis sp. may be employ in remediation as well as biodiesel production.
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