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Background: Atrophic gastritis and intestinal metaplasia are precancerous conditions associated with Helicobacter pylori infection. The prevalence of these conditions varies among countries and even among different regions in same country. There is limited data from central Nepal regarding these entities. The primary aim of this study was to assess the prevalence of atrophic gastritis in gastric biopsy of symptomatic patients. Methods: A prospective study which included all consecutive patients undergoing endoscopic gastric biopsy. Biopsies from body and antrum obtained as per Sydney protocol. Histopathological examination was done by a team of histopathologists and reported according to updated Sydney classification. Statistical software SPSS (version 26, SPSS Inc. Chicago, IL) and STATA 14 were used for statistical analysis. Results: Of 113 consecutive patients, 103 were included for final analysis (female: 59.2% and mean age: 46.29 ± 16.54 years). Dyspepsia [EPS: 69 (66.9%) and PDS:19 (18.4%)] followed by GERD in 21 (20.3%) were the commonest presentations. On histology, atrophic gastritis was present in 101 (98.05%) patients with mild-, moderate-, and severe AG seen in 12 (11.8%), 87 (86.1%), and 2 (1.9%) respectively. Prevalence of AG was not different in patients with or without H. pylori infection (p=0.10). Intestinal metaplasia was present in 13 (12.62%). Helicobacter pylori were present in 58 (56.3%) with prevalence in antrum and body being 57 (55.3%) vs. 41 (39.8%), p=0.02. Conclusions: Atrophic gastritis, IM, and H. pylori infection is highly prevalent in symptomatic patients and the prevalence in younger population is equally high compared to older population.

In this study, we have investigated the structural, electrical transport and UV–Visible properties of polycrystalline La0.7Ca0.3−xKxMnO3 (x = 0.0, 0.05, 0.10, 0.20) ceramic samples prepared by conventional solid-state reaction. The structure characterized by X-ray diffraction shows that the samples possess orthorhombic perovskite structure belonging to Pnma space group with some impurity for higher doping level (x = 0.10, 0.20) and cell volume is enlarged with Ca2+ substitution by K1+. The surface morphology was investigated by field emission scanning electron microscope, which indicates that the samples with better crystallization having higher density. The electrical transport properties were measured by the standard four-probe method, which demonstrates that the resistivity decreases non-monotonically and the metal–insulator transition temperature (TP) shifts to higher temperature with increasing K1+ content, the electrical transport behavior for metal and insulator region was explained using Zener double exchange model and small polaron hopping model respectively. Furthermore, the progressive substitution of Ca2+ by K1+ broadens the metal–insulator transition and reduces the temperature coefficient of resistivity. Room temperature UV–Vis studies show that the optical band gap changes with the partial replacement of Ca2+ with K1+. The investigations clearly show the effect of impurity present on structural, electrical transport and UV–visible response of the prepared ceramic samples.

International audience; The objective of this research is to examine how ultrasonication time affects agglomeration, stability, thermal conductivity, and viscosity of CuO nanofluid. Using different reaction conditions, distinct shaped CuO nanoparticles are synthesised and dispersed in an EG: DW (70:30) ratio with 0.3 vol%. Microscopic and TEM images are used to analyze colloidal solutions with varying sizes and shapes of nanoparticles. After 30 days of preparation, the zeta potential is measured to ensure that the suspension is stable. The Bridgman equation is used to compute thermal conductivity using sound velocity values. Viscosity of colloidal suspension is measured by viscometer. All of the studies are performed at 30° ± 2 °C room temperature for ultrasonication times ranging from 30–120 min. At an optimal sonication time of 80 min, there is less agglomeration and more stable particle dispersion. In comparison to other morphological suspensions, CuO spherical shape suspended nanofluid has the lowest viscosity and maximum thermal conductivity, as well as the most stable fluid. At the optimal sonication period, measured results demonstrate thermal increase and decreased viscosity, which could have implications for heat transfer applications.

We have successfully synthesized multi-layer graphene oxide and graphene oxide based magnetic nanocomposite (M/GO) by microwave-assisted modified Hummers’ method for removal of toxic lead (Pb2+) and cadmium (Cd2+) ions from aqueous solution. The X-ray diffraction spectra of synthesized graphene oxide and M/GO confirm increased interlayer spacing along c-axis. Raman spectra revealed the good quality of synthesized GO and M/GO. The wrinkles were seen in the SEM images of synthesized graphene oxide. The presence of conjugated double bond (C C) and carbonyl (C O) were confirmed by using the UV–Vis spectroscopic spectra. Brunauer–Emmett–Teller (BET) analysis showed high (126 m2/g) surface area M/GO composite which accounts for large number of active binding sites for the adsorption of heavy metal ions. The adsorption studies revealed that Pb2+ ions were efficiently adsorbed on GO sheets. Interestingly, M/GO showed better adsorption for cadmium ions.

Inflammatory bowel disease (IBD), once considered a disease of the Western hemisphere, has emerged as a global disease. As the disease prevalence is on a steady rise, management of IBD has come under the spotlight. 5-Aminosalicylates, corticosteroids, immunosuppressive agents and biologics are the backbone of treatment of IBD. With the advent of biologics and small molecules, the need for surgery and hospitalization has decreased. However, economic viability and acceptability is an important determinant of local prescription patterns. Nearly one-third of the patients in West receive biologics as the first/initial therapy. The scenario is different in developing countries where biologics are used only in a small proportion of patients with IBD. Increased risk of reactivation of tuberculosis and high cost of the therapy are limitations to their use. Thiopurines hence become critical for optimal management of patients with IBD in these regions. However, approximately one-third of patients are intolerant or develop adverse effects with their use. This has led to suboptimal use of thiopurines in clinical practice. This review article discusses the clinical aspects of thiopurine use in patients with IBD with the aim of optimizing their use to full therapeutic potential.

Surgery, chemotherapy and radiotherapy, the conventional treatment modalities of cancer though successful are limited by presence of residual tumor cells, toxic side-effects and treatment resistance, thus raising the need for investigating other novel approaches. Here, we have used a cold atmospheric plasma (CAP) jet and assessed the in vitro efficacy in gingivobuccal squamous cell carcinoma (GB-SCC) – ITOC-03, breast adenocarcinoma—MCF7 and HEK293 cells. Cells lines were subjected to varying doses of ionizing radiation (0, 2, 4, 6, 8 Gy) and CAP jet treatment (0, 60, 180, 240, 300 s). CAP jet treatment showed time dependent increase in H2O2 and NO2− concentration. Cell viability assay showed potent effect of CAP jet on all three cell lines in comparison to radiation treatment, while helium gas treatment showed minimal inhibitory effect. Irradiated, CAP jet and helium gas treated cells showed loss of nucleic acid features, 788 cm−1 and 1340 cm−1 in Raman spectra, indicating DNA damage. Principal Component Analysis (PCA) showed distinct classification of CAP-treated and control cells, while Principal Component – Linear Discriminant Analysis (PC-LDA) based classification of Raman spectra showed ITOC-03 and HEK293 cells to be sensitive to CAP jet and radiation treatment in comparison to MCF7 cells. Collectively, cell viability assay and Raman spectroscopy have shown potent effect of CAP jet in GB-SCC and breast adenocarcinoma cells.

Chitosan (CTS) functionalized Halloysite Nanotubes (HNT) have been used as receptive nano-supports for the grafting of copper (Cu) and laccase (Lac) for the degradation of chlorpyrifos. The developed nanocomposite Lac@Cu-CTS-HNT showed 83.4% Lac immobilization which was further characterized by TEM, SEM-EDX, FTIR, XRD, DSC and TGA. The chlorpyrifos degradation studies were performed under constant stirring for 24 h with both free enzyme and Lac@Cu-CTS-HNT and were analysed through HPLC. Percentage degradation of chlorpyrifos with the nanocomposite went as high as 97% for 50 μg/mL chlorpyrifos at neutral pH and room temperature. Variable pesticide and nanocomposite concentration, pH, and temperature studies for pesticide degradation were also performed, followed by reusability studies. The nanocomposite maintained its degradation ability at ~97% even at variable temperature and pH conditions. Reusability study was performed 5 times wherein the degradation percentage remained the same after 5 cycles (~95%). Degradation kinetics were also performed for the nanocomposite in the presence and absence of the immobilized enzyme. Through this study, it is suggested that Lac@Cu-CTS-HNT can be a potential nano-catalyst for the degradation of chlorpyrifos in aqueous environment.

Aim: We conducted this network meta-analysis to compare the efficacy and safety of targeted pharmacotherapies and fecal microbial transplantation (FMT). Patients & methods: Nineteen studies were included and there was only one head-to-head randomized controlled trial (adalimumab vs vedolizumab). Results: All interventions, including FMT, were superior to a placebo in inducing clinical remission (except adalimumab – odds ratio 1.66; 95% CI: 0.97–2.85), clinical response and endoscopic remission. FMT was comparable with other agents in achieving all efficacy outcomes. Infliximab was ranked highest in inducing clinical remission (surface under the cumulative ranking, 0.8). There was no difference in safety outcomes between FMT and other targeted therapies. Conclusion: FMT is as efficacious and as safe as other targeted therapies in inducing clinical remission, clinical response and endoscopic remission. Further studies to assess the long-term benefits are needed in order to reach a definitive conclusion.

In the present work, nanostructured functionalized silica is coated on an aluminum (Al) substrate by the spray pyrolysis method to create a stable and effective super-hydrophobic substrate for water harvesting via moist air. Substrate characterization reveals that (1) major diffraction peaks corresponding to crystoballite SiO2 (C-SiO2), quartz (Q-SiO2), Al2O3, and Al2SiO5 are to be found at SiO2/Al interface; (2) strong chemically bonded methyl functionalized silica is confirmed on the Al surface by Fourier-transform infrared spectroscopy (FT-IR) and x-ray photoelectron spectrometry (XPS) shows the presence of Al-O-Si bond at the interface; and (3) the equilibrium contact angle of the water droplet on the coated substrate is measured to be 156° ± 5° with a hysteresis of 10° ± 3°. The coating is found to be stable for more than 365 days in a humid atmosphere. Finally, moist air condensation experiments confirm substantial augmentation of condensate collected ranging from 188 ml/m2-h over an untreated aluminum substrate to 750 ml/m2-h over the coated substrate. Hence, it is concluded that nanostructured silica-coated Al substrate is highly effective for enhancing the condensation of water vapor from a moist air environment.

The study aims to examine the clustering of infant deaths in India and the relative contribution of infant death clustering after accounting for the socio-economic and biodemographic factors that explain the decline in infant deaths. The study utilized 10 years of birth history data from three rounds of the National Family Health Survey (NFHS). The random effects dynamic probit model was used to decompose the decline in infant deaths into the contributions by the socio-economic and demographic factors, including the lagged independent variable, the previous infant death measuring the clustering of infant deaths in families. The study found that there has been a decline in the clustering of infant deaths among families during the past two and half decades. The simulation result shows that if the clustering of infant deaths in families in India was completely removed, there would be a decline of nearly 30 percent in the infant mortality rate (IMR). A decomposition analysis based on the dynamic probit model shows that for NFHS-1 and NFHS-3, in the total change of the probability of infant deaths, the rate of change for a given population composition contributed around 45 percent, and about 44 percent was explained by a compositional shift. Between NFHS-3 and NFHS-4, the rate of change for a given population composition contributed 86%, and the population composition for a given rate contributed 10% to the total change in the probability of infant deaths. Within this rate, the contribution of a previous infant was 0.8% and the mother’s age was 10%; nearly 31% was contributed by the region of residence, 69% by the mother’s education, and around 20% was contributed by the wealth index and around 8.7% by the sex of the child. The mother’s unobserved factors contributed more than 50 percent to the variability of infant deaths in all the survey rounds and was also statistically significant (p < 0.01). Bivariate analysis suggests that women with two or more infant losses were much less likely to have full immunization (10%) than women with no infant loss (62%), although institutional delivery was high among both groups of women.

Background Since 2005, India has experienced an impressive 77% reduction in maternal mortality compared to the global average of 43%. What explains this impressive performance in terms of reduction in maternal mortality and improvement in maternal health outcomes? This paper evaluates the effect of household wealth status on maternal mortality in India, and also separates out the performance of the Empowered Action Group (EAG) states and the Southern states of India. The results are discussed in the light of various pro-poor programmes and policies designed to reduce maternal mortality and the existing supply side gaps in the healthcare system of India. Using multiple sources of data, this study aims to understand the trends in maternal mortality (1997–2017) between EAG and non EAG states in India and explore various household, economic and policy factors that may explain reduction in maternal mortality and improvement in maternal health outcomes in India. Methods This study triangulates data from different rounds of Sample Registration Systems to assess the trend in maternal mortality in India. It further analysed the National Family Health Surveys (NFHS). NFHS-4, 2015–16 has gathered information on maternal mortality and pregnancy-related deaths from 601,509 households. Using logistic regression, we estimate the association of various socio-economic variables on maternal deaths in the various states of India. Results On an average, wealth status of the households did not have a statistically significant association with maternal mortality in India. However, our disaggregate analysis reveals, the gains in terms of maternal mortality have been unevenly distributed. Although the rich-poor gap in maternal mortality has reduced in EAG states such as Bihar, Odisha, Assam, Rajasthan, the maternal mortality has remained above the national average for many of these states. The EAG states also experience supply side shortfalls in terms of availability of PHC and PHC doctors; and availability of specialist doctors. Conclusions The novel contribution of the present paper is that the association of household wealth status and place of residence with maternal mortality is statistically not significant implying financial barriers to access maternal health services have been minimised. This result, and India’s impressive performance with respect to maternal health outcomes, can be attributed to the various pro-poor policies and cash incentive schemes successfully launched in recent years. Community-level involvement with pivotal role played by community health workers has been one of the major reasons for the success of many ongoing policies. Policy makers need to prioritise the underperforming states and socio-economic groups within the states by addressing both demand-side and supply-side measures simultaneously mediated by contextual factors.

The polycrystalline M-type barium hexaferrite (BaFe12−xAlxO19) with x = 0.0, 1.0, 2.0, and 3.0 have been prepared by the sol–gel Method. The crystal structure of all the samples is found to be in hexagonal symmetry with P63/mmc space group. The impedance was studied over a range of frequencies (1 Hz–1 MHz) for all the compositions. Direct current (DC) electrical resistivity measurements of all the samples were carried out in the temperature range of 303–775 K. All the samples exhibit the semiconducting behavior. The resistivity increases with the increase in Al3+ substitution. The impedance along with DC resistivity results established the electron hopping conduction mechanism in the Al3+ substituted barium hexaferrites. The electrical conductivity has been well explained by the Mott variable-range hopping mechanism of localized polarons. The dielectric dipoles are frozen at low temperature and activated at high temperature as observed two transition temperatures in temperature versus impedance plot. A correlation between ac impedance and DC resistivity has been established in the M-type hexaferrite magnetic semiconductor.

The condensation transport coefficients are higher on the metallic surface because of the high thermal conductivity of metallic surfaces. However, the metallic surfaces have a higher affinity to water in the condensation process which leads to corrosion and results in damage to the condensing metallic surface. Low surface energy and low wettability surfaces promote efficient condensation in drop mode. Therefore, several surface modification techniques have been adopted for modifying the surface wettability of the metallic surfaces. Teflon coating on the metallic surface has been an economically viable and simple method for fabricating low surface energy coating on metallic surfaces. In this work, Cu coil is coated with PTFE film for fabricating hydrophobicity on Cu helical coil. Moist air condensation experiments are carried out on Teflon coated and bare Cu coil to investigate the effect of Teflon coating on the coil. In addition, the effect of moist ambient conditions on the Teflon coated coil is addressed to examine the aging of the Teflon coating on the Cu coil. The results show that the characteristics of hydrophobic Teflon coating deplete with increases in exposure time so the dropwise condensation transits into mixed condensation and ultimately in film mode as the coil is exposed to repeated condensation cycles. The results of the present study are useful to appropriately investigating in which all applications the Teflon coating can be implemented such that all its properties are retained in that time duration.

Perianal fistula is one of the most challenging complications of Crohn’s disease (CD). We aimed to describe treatment response with surgical and medical therapies, and long-term complications. We retrospectively analyzed records of patients with perianal fistulizing CD who were prospectively followed from January 2005 to December 2018. Among 807 patients, 81 (10%) had perianal fistula and 65 were included in the final analysis. The mean age of presentation was 27.4 ± 10.3 years, and 78.5% were males with a median duration of follow-up of 45 (IQR, 24–66) months. 75.4% (n = 49) had complex fistulae. 55.4% (n = 36) of patients received multiple courses (> 5 courses) of antibiotics. Complete response rates with immunomodulators, fistula surgery, biologicals, and diversion were 25%, 42.8%, 39.5%, and 45.4%, respectively. The relapse rate was highest after fistula surgery (52.6%). 44.6% of patients received medical (immunomodulators—21 and biologicals—8) whereas 46.1% received surgery as the first-line therapy. The absence of perianal abscess was associated with complete fistula closure. One patient developed malignancy and 4 (6.1%) died at the end of follow-up. Among the patients (n = 28) who received biologicals, TB reactivation occurred in one patient (3.5%). Medical therapy should be offered as first-line therapy, and immunomodulators can be considered when patients cannot afford biologicals. Surgery offers temporary improvement and is associated with high relapse rates. Absence of perianal abscess predicts long-term complete fistula closure.

Fabrication of highly dense conical nanostructures and their subsequent controlled metallization make them ideal candidates for enhancing cold cathode electron emission efficiency. For instance, hierarchical growth of self-assembled noble metal nanoparticles on self-organized nanostructured materials offers the advantage of fabricating low threshold cold cathode electron emitters. However, the fabrication of stable Si nanostructure-based cold cathode electron emitters with ultra-low threshold fields is a challenging task. This report presents cold cathode electron emission from Au-NP-decorated ensembles of self-organized silicon nanofacets (Si-NFs) having fascinating ultralow turn-on fields (as low as 0.27 V μm−1) and remarkably low threshold electric fields (as low as 0.37 V μm−1) with outstanding stability. It is interesting to note that even as-prepared Si-NFs offer hitherto unseen low turn-on fields (as low as 0.58 V μm−1) and threshold electric fields (0.66 V μm−1) – so far as silicon-based nanostructures are concerned. Kelvin probe force microscopy studies reveal that tunability in the work function of Au-NP-decorated Si-NF samples depends on the dimension and growth-angle of gold nanoparticles (Au-NPs). In addition, in-depth dual pass tunnelling current microscopy measurements demonstrate that the Au-NPs on the apexes and sidewalls of Si-NFs act as cold cathode electron emission sites which help to improve the turn-on and threshold fields for Au-NP-decorated Si-NFs in comparison to their as-prepared counterparts where electron emission takes place mostly from their sidewalls and valleys. Furthermore, finite element electrostatic field-based simulations reinforce the experimental observations. The present investigation paves the pathway to the fabrication of self-organized Si nanostructure-based highly stable cold cathode electron emitting devices having fascinating low turn-on and threshold fields along with extremely high field enhancement factors and high stability for use in nanoscale electronic devices.

Ion beam sputtering, known as potential technique for producing nanoripple on various surfaces having wide range of applications. Along with nanoripple, triangular features are also superimposed, limiting their use for some potential applications. Here we are reporting evolution of triangular features on Ge (100) surfaces under low energy (300–1000 eV) Xe ion irradiation at room temperature for angles of incidence (61°–80°) and ion fluences of (5.34 × 1017−8.01 × 1018 ions cm−2). Triangular features appear with the onset of ripple formation and disappear when the ripple periodicity is lost. These features formation depend not only on material but also depend on the ratio of the ion/target mass. In comparison with numerical simulations based on modified anisotropic Kuramoto-Sivanshinsky equation, we find good agreement for the evolution of base angle and lateral length for the triangular features with ion incidence angle. The dynamics of triangular feature with ion incidence angle and ion fluence have been reported. Ion-incidence angle dependency is adequately replicated in numerical simulations. Experimentally the base angle and lateral length increases with increase in ion incidence angle, similar trend is observed in numerical simulation.

A comparative study is carried out to observe the effect of dispersing Zinc Oxide (ZnO) nanoparticles in two different host matrices of Polyvinylalcohol (PVA)—Polyvinylpyrrolidone (PVP)—Polyvinylalcohol (PVA)—Carboymethyl Cellulose (CMC) on their structural, optical and electrical properties. The concentration of ZnO in the blend films was kept low. The XRD diffractogram of both the polymer nanocomposite films (PNCs) exhibited characteristic peaks of ZnO confirming the dispersion of nanoparticles in blended films. The SEM micrographs of these PNC films had shown uniform dispersion of ZnO nanoparticles in both matrices. The analysis of optical and electrical properties indicates appreciable modification in these properties on inclusion of small amount of ZnO in both the matrices. ZnO dispersed PVA–CMC film shows enhanced absorption in UV region with decreased band gap and higher σdc values as compared to ZnO dispersed PVA–PVP film suggesting PVA–CMC–ZnO film to be a promising material in the area of green electronics and optoelectronics.

Aluminide coatings with a top alumina layer on 9Cr steels are considered candidates for fusion blanket applications. One of the critical issues associated with such coating is the fabrication sequence. It is therefore important to investigate the effect of aluminide coating on weld properties of 9Cr steels. This work is a preliminary investigation of the weldability of aluminide coated 9Cr-1Mo steels using bead-on-plate welding experiments. Alumina coated GRADE 91 steel samples by hot dip aluminizing followed by normalizing and plasma tempering were generated. Bead-on-plate welding studies were conducted at different heat inputs by varying the weld speed (100,125,150 mm/min) and using a constant current of 200 A by autogenous tungsten inert gas (TIG) welding process. The effect of coating on the weld microstructure was investigated using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive x-rays (SEM-EDX) and microhardness tests. It was observed that the presence of alumina (Al2O3) on the top of coated samples resulted in improved depth of penetration (DOP) due to arc constriction. The presence of Al rich inclusions (AlN) in the weld bead were also observed. The marginal increase in Al concentration of the weld bead appears to reduce the grain size of weld metal for coated sample and microhardness was enhanced compared to the uncoated 9Cr-1Mo steels.

In recent work, CuO nanofluid is prepared with and without PVA (poly(vinyl alcohol)) coated surfactant nanoparticles suspension in distilled water: ethylene glycol (DW:EG) (60:40) ratio for 0.1 wt% and 0.5 wt% concentration of fluid by two-step technique. Our work describes a simple and cost effective chemical precipitation method to synthesis CuO nanoparticles with the addition of synthetic polymer (PVA) allows the modification of physical properties of copper oxide (CuO) nanoparticles. The scanning electron microscopy (SEM) shows the morphological difference in nanocrystallite size and shape between without surfactant coated nanoparticles and with PVA coated particles. XRD pattern of CuO particles reveal that high crystal quality with the monoclinic crystal structure where PVA coated particles have crystallite size 15 nm and without coating it is 31 nm. UV-Vis (ultraviolet absorption spectroscopy) spectra confirmed that the CuO absorption peak at 292 nm and 445 nm for CuO+ PVA. Fourier transform infrared spectra (FTIR) spectroscopy studies show the interaction between PVA and CuO nanoparticles. Experimental results concluded that for CuO + PVA nanofluid, particle size is smaller and showing more stable fluid from zeta potential values. Thermal conductivity results are carried from sound velocity of fluid by Bridgman's equation. As the particle concentration increases in fluid, thermal enhancement is noted. It was found that the viscosity of nanofluid is lower with a larger size particle at the same temperature and for the same concentration. Therefore, our result shows that CuO nanofluids have good potential for effective heat transfer application.

Background: India and many of its bigger states could not achieve the national goal related with child health based on 4th UN Millennium Development Goal. There is a need to look for different approaches which deal with infant mortality. Literature emphasizes clustering of infant deaths in families has implications on infant mortality. Objective: The present study attempts to examine the levels, trends, and differentials of clustering of infant deaths in families in India using National Family Health Survey (NFHS) dataset and how they changed over the years. Materials and Methods: Study used bivariate analysis and multilevel random effects logit model based intraclass correlation coefficient and median odds ratio to examine the clustering of deaths in families, in India. Results: There has been a consistent decline in both infant mortality rate (IMR) and clustering of infant deaths in families in India between 1992 and 2016. However, the pace of decline was faster after 2005. States such as Uttar Pradesh, Madhya Pradesh, and Bihar are the major contributors in clustering of infant deaths in families. In Kerala, clustering of infant deaths has been disappeared in families while among relatively more developed states such as Maharashtra and Tamil Nadu have experienced a reduction in clustering of infant deaths in families by an amount of 30 years and for mothers who have received higher education. IMR can be reduced to a greater extent if government policies and health resources are directed toward the families experiencing the clustering of infant deaths.

Delta (δ) ferrite phase has several detrimental effects on mechanical properties such as toughness, creep, impact and ductility. It is necessary to examine δ-ferrite content in the weld zone of aluminized coated steels. This manuscript presents the investigation of δ-ferrite formation in the weld of aluminized P91 steels. The welds were prepared with different heat inputs by varying the weld speed at constant current by autogenous Tungsten Inert Gas (TIG) welding process. The concentration of Al in the weld zone may favor δ-ferrite formation during the welding as Al is a ferrite former. Hence, the weld zone prepared at maximum heat inputs was compared for both coated and bare P91 samples. Microstructures were examined and correlated with the temperatures and cooling curve measured during welding. The various empirical formulae such as Schneider, Schaeffler, Newhouse, and Kaltenhauser were used to predict the δ-ferrite formation based on the chemical composition of weld metal obtained with the help of spark emission spectroscopy. Among these, Kaltenhauser’s equation is more accurate for aluminized coated P91 steels. X-ray diffraction, optical microscopy, scanning electron microscopy, and microhardness measurement were done to analyze and predict the shape and morphology of δ-ferrite for coated steel and bare P91 steels. The investigation indicates that higher heat input (~ 2.12 kJ/mm) for coated steel and Al concentration (~ 0.19%) in the weld zone caused the formation of δ-ferrites in various shapes such as polygonal and isolate islands and it has an average volume fraction of ~ 5.09%. The average microhardness values were ~ 396–410 Hv for martensitic laths, while it was ~ 192–198 Hv for delta ferrite which is 52% lower.

An effective method has been proposed for controlling the size distributions of metallic nanoparticles produced through laser ablation in liquid by employing physical boundaries in the vicinity of the ablation site. An Nd:YAG laser (1064 nm, FWHM 6 ns) has been used to ablate the copper target immersed in two different liquid medium, water and isopropyl alcohol. Water and isopropyl alcohol have been chosen because of the significant differences in their densities while the optical properties are nearly comparable. To demonstrate the efficacy of the method, experiments have been conducted in both the configurations, that is, with and without confining boundaries. To ascertain the observed effect, select experiments have also been carried out with gold as the target material to ensure that the size distribution is not influenced because of oxide-layer formation. The size of the particles were estimated from the SEM images and analysing these images using an indigenously developed code. It has been observed that there are significant differences in the size distributions in the cases of nanoparticles produced with and without confining boundaries. For any given medium, a consistent increase in the mean size of the nanoparticles produced with the targets fitted with physical boundary has been observed as compared to those produced with flat targets. The observed trend has been attributed to the plausible role of the shock wave reflection from the physical boundaries, which alters the plasma parameters. Reflected shock wave–plasma interactions prolonging the thermalisation time of the plasma plume in confined geometry facilitate the particle growth, resulting in the formation of bigger particles. The proposed method, which can be applied to any metallic target, is one of the greener methods for producing nanoparticles and is also relatively simple and cost effective.

In this study, we have demonstrated the fabrication of one of the few lead-free perovskite photodetectors reported to date. In particular, we fabricated the photodetector based on a methylammonium bismuth iodide, MA3Bi2I9 (MABI), structure that works under a self-powered mode of operation. The optoelectronic properties of the photodetector were investigated systematically. The photoresponse of the photodetector was carefully studied and compared with the literature, which demonstrated the capability of the MABI structure for detecting light at a very low incident irradiance of 10 μW cm-2. Also, it exhibited a fast and reproducible response speed along with high photosensitivity (∼105) and detectivity (∼1012 Jones) at low operating voltages (0 V and 0.8 V) through the large effective device area. It was also revealed that the MABI photodetector had good stability after storage for two months at ambient conditions. It is therefore concluded that our photodetector fabricated with a MABI perovskite structure using a simple geometry has great potential to further improve the optoelectronic properties when proper electron/hole-transporting layers are fused for proper charge extraction. This will have significant benefits for next-generation cost-competitive optoelectronic technology to address the scalability issue.