In this research work, atomic and molecular orbitals based analysis has been made to see electronic structure of platinum halides (platinum dichloride, platinum dibromide, platinum diiodide and platinum difluride). Th...In this research work, atomic and molecular orbitals based analysis has been made to see electronic structure of platinum halides (platinum dichloride, platinum dibromide, platinum diiodide and platinum difluride). The geometry optimization and three dimensional (3D) modeling of the above mentioned species have been made on CAChe pro software. The results show: (i) The involvement of three p atomic orbitals is negligible as their summation values are very low in comparison to d orbital and considerably low with respect to s orbital. (ii) The study well support the Landis concepts of sdn-hybridation (here n = 1) as bond angle and contributions of s-orbital and d-orbital of Pt(II) are maximum with negligible contribution of p-orbitals. (iii) These halides also support the cloud-expanding effect with experimental data and also follow the nephelauxetic effect. The result is in good agreement with experiment results that covalent character increases in the order: PtI2 > PtBr2 > PtCl2 > PtF2. (iv) And thus the study will help to fine tune the existing complexes of these halides.展开更多
AI 5083//10 wt% SiCp nano composites have been synthesized by means of high energy ball milling followed by spark plasma sintering （SPS）. Nano composites produced via this method exhibited near-theoretical density w...AI 5083//10 wt% SiCp nano composites have been synthesized by means of high energy ball milling followed by spark plasma sintering （SPS）. Nano composites produced via this method exhibited near-theoretical density while retaining the nano-grained features. X-ray diffraction （XRD） analysis indicated that the crystalline size of the ball milled AI 5083 matrix was observed to be～25 nm and it was coarsened up to～30 nm after SPS. Nano indentation results of nano composites demonstrated a high hardness of～280 HV with an elastic modulus of 126 GPa. Wear and friction characteristics with addition of SiCp reinforcement exhibited significant improvement in terms of coefficient of friction and specific wear rate to that of nano structured AI 5083 alloy. The reduction in specific wear rate in the nanocomposite was mainly due to the change of wear mechanism from adhesive to abrasive wear with the addition of SiCp which resulted in high hardness associated with nano-grained microstructure.展开更多
Nano silver （Agn） is employed as an active antimicrobial agent, but the environmental impact of Agn released from commercial products is unknown. The quantity of nanomaterial released from consumer products during u...Nano silver （Agn） is employed as an active antimicrobial agent, but the environmental impact of Agn released from commercial products is unknown. The quantity of nanomaterial released from consumer products during use should be determined to assess the environmental risks of advancement of nanotechnology. This work investigated the amount of silver released from three different types of fabric into water during washing. Three different types of fabric were loaded with chemically synthesized Ag nanoparticles and washed repeatedly under simulated washing conditions. Variable leaching rates among fabric types suggest that the manufacturing process may control the release of silver reaching the waste water treatment plants. In an attempt to recover the Agn for reutilization and to save it from polluting water, the effluents from the wash were efficiently treated with bacterial strains. This treatment was based on biosorption and was very efficient for the elimination of silver nanoparticles in the wash water. The process ensured the recovery of the Agn leached into the effluent for reutilization, thus preventing environmental repercussions.展开更多
We report an electrodeposited poly(pyrrole-co-pyrrolepropylic acid) copolymer modified electroactive graphene-carbon nanotubes composite deposited on a glassy carbon electrode to detect the protein antigen(cTnI). The ...We report an electrodeposited poly(pyrrole-co-pyrrolepropylic acid) copolymer modified electroactive graphene-carbon nanotubes composite deposited on a glassy carbon electrode to detect the protein antigen(cTnI). The copolymer provides pendant carboxyl groups for the site-specific covalent immobilization of protein antibody, antitroponin I. The hybrid nanocomposite was used as a transducer for biointerfacial impedance sensing for cTnI detection.The results show that the hybrid exhibits a pseudo capacitive behaviour with a maximum phase angle of 49° near 1 Hz,which is due to the inhomogeneous and porous structure of the hybrid composition. The constant phase element of copolymer is 0.61(n = 0.61), whereas, it is 0.88(n = 0.88) for the hybrid composites, indicating a comparatively homogeneous microstructure after biomolecular functionalization. The transducer shows a linear change in charge transfer characteristic(R_(et)) on cTnI immunoreaction for spiked human serum in the concentration range of 1.0 pg mL^(-1)–10.0 ng mL^(-1). The sensitivity of the transducer is 167.8 ± 14.2 Ω cm^2 per decade, and it also exhibits high specificity and good reproducibility.展开更多
Vehicular emissions are considered one of the major anthropogenic sources of greenhouse gases and poor air quality in metropolitan cities.This study aims to see the correlation of CO_(2),CH_(4),and CO through monitori...Vehicular emissions are considered one of the major anthropogenic sources of greenhouse gases and poor air quality in metropolitan cities.This study aims to see the correlation of CO_(2),CH_(4),and CO through monitoring over a period from December 2020 to October 2021 covering three seasons’winter,summer,and monsoon at two different traffic locations of Delhi having different traffic volumes,road patterns,and traffic management.The annual average morning concentration of CO_(2),CH_(4)and CO was found(533±105),(7.3±3.1),(10.7±3.0)ppm at Najafgarh and(480±70),(5.2±1.8),(7.8±2.8)ppm at Rajendra Place,respectively.A relationship between concentration of all three gases and meteorological parameters such as temperature,humidity,wind speed and wind direction has also been investigated using Pearson correlation coefficient and pollution rose diagram.A comparable pattern in concentration was observed for all three gases in spatial(location)and temporal(diurnal)distribution.The concentration trend of CO_(2)in different seasons is winter>summer>monsoon,while in the case of CH_(4)winter=summer>monsoon but not any seasonal trend was noted in CO case.It is observed that CO_(2)has a good relation with CO(a tracer for vehicular emission)in terms of diurnal variation,whereas,CH_(4)does not represent a relation with CO and CO_(2)diurnally,suggesting that vehicles are the source of CO_(2)but not much contributing to other greenhouse gases like CH_(4).展开更多
Novel and simplified bi-layer top-emitting white organic light emitting diodes(OLEDs)with dual co-host emitters have been simulated and analyzed.They consist of yellow-green emitting layer(EML)as electron transport la...Novel and simplified bi-layer top-emitting white organic light emitting diodes(OLEDs)with dual co-host emitters have been simulated and analyzed.They consist of yellow-green emitting layer(EML)as electron transport layer(ETL)and blue EML as hole transport layer(HTL).Novelty of the device lies in simplification of tri-layer white OLED to a bi-layered device which is done by merging yellow-green EML with ETL and blue EML with HTL.The simulated devices show Commission Internationale de L’Eclairage(CIE)colour coordinates well within the emission range of white light.The results show that device A with 5,6,11,12-tetraphenylnaphthacene(rubrene)doped ETL has achieved the lowest luminance but longest excited state lifetime.Device D with tris-(8-hydroxyquinoline)aluminum:4-(dicyanomethylene)-2-t-butyle-6-(1,1,7,7-tetra-methyljulolidyl-9-enyl)4 H-pyran(Alq3:DCJTB)as ETL which emits yellow light and 2,7-bis[N,N-bis(4-methoxy-phenyl)amino]-9,9-spirobifluorene(MS-TPD):bis(2-methyl-8-quninolinato)-4-phenylphenolate alu-minium(BAlq)as HTL which is responsible for blue light emission is found to have best characteristics when compared to other simulated devices.It has a maximum luminance of 10000 cd/m2 and current efficiency of 15.25 cd/A,respectively,and CIE coordinates are at(0.329,0.319).The device is found to be compatible to be used in solid state lighting applications because of the low driving voltage of the device.展开更多
The present study highlights the potential application of zinc peroxide （ZnO2） nanomaterial as an efficient material for the decontamination of cyanide from contaminated water. A process patent for ZnO2 synthesis ha...The present study highlights the potential application of zinc peroxide （ZnO2） nanomaterial as an efficient material for the decontamination of cyanide from contaminated water. A process patent for ZnO2 synthesis has been granted in United States of America （US Patent number 8,715,612; May 2014）, South Africa, Bangladesh, and India. The ZnO2 nanomaterial was capped with polyvinylpyrrolidone （PVP） to control the particle size. The PVP capped ZnO2 nanomaterial （PVP-ZnO2） before and after adsorption of cyanide was characterized by scanning electron microscope, transmission electron microscope, X-ray diffractorneter, Fourier transform infrared spectroscopy and time of flight-secondary ion mass spectrom- etry. The remaining concentration of cyanide after adsorption by PVP-ZnO2 was determined using ion chromatograph. The adsorption of cyanide over PVP-ZnO2 was also studied as a function of pH, adsorbent dose, time and concentration of cyanide. The maximum removal of cyanide was observed in pH range 5.8-7.8 within 15 rain. The adsorption data was fitted to Langmuir and Fruendlich isotherm and it has been observed that data follows both the isotherms and also follows second order kinetics.展开更多
Recognizing the composition and modulation of the microbiome, a viable therapeutic tool for multi-targeted therapy is a new strategy that has recently been explored. Glucosamine (GS) is being studied for its prebiotic...Recognizing the composition and modulation of the microbiome, a viable therapeutic tool for multi-targeted therapy is a new strategy that has recently been explored. Glucosamine (GS) is being studied for its prebiotic potential in addition to being the most abundant and naturally occurring amino monosaccharide. The current study focuses on glucosamine’s prebiotic potential by assessing the stability of various GS concentrations (1% - 5%) in the gastrointestinal tract (GIT) and its ability to be fermented by the gut microbiota. The results showed that GS stimulated the most growth in L. acidophilus even after a longer incubation time than B. bifidum and L. acidophilus growth was concentration-dependent, with maximum growth at 3% with a simultaneous decrease in pH (5.6 - 1.7). The decrease in GS concentration with time also represented the growth of bacterial species, demonstrating the species’ utilization of GS. Furthermore, at 3%, GS also represented the prebiotic index of 1.9. In addition, the concentration of GS in various simulated GIT fluids was estimated in both fast and fed conditions to examine GS stability at various levels in the gut. The results showed that GS remained unaffected and non-digestible in all of the simulated GIT fluids (salivary, gastric, intestinal, and colonic), but there was a slight decrease in GS concentration (2.8%) in the fasted state of gastric fluid due to low pH levels (1.6). As a result, the findings are conclusive and suggest that GS possesses prebiotic properties.展开更多
The coal is contaminated with toxic metals at the trace levels. They are released into the environment during mining, handling and burning of coal. The Korba basin has one of the largest coal exploitation areas in the...The coal is contaminated with toxic metals at the trace levels. They are released into the environment during mining, handling and burning of coal. The Korba basin has one of the largest coal exploitation areas in the country. In this work, contamination and sources of toxic metals i.e. Hg and Pb in the air, soil and sediment of the Korba basin, India are described. The concentration of Hg and Pb in the ambient air was ranged from 7.4 - 29 and 7.0 - 585 ng/m3 with mean value of 18 ± 4 and 129 ± 104 ng/m3 in the winter season. The mean concentration of Hg in the soil and sediment was 0.22 ± 0.03 and 0.44 ± 0.08 mg/kg, respectively. The higher concentration of Pb in the environmental samples was observed.展开更多
Ritonavir sulfate is a protease inhibitor widely used in the treatment of acquired immunodeficiency syndrome. In order to elucidate the inherent stability and sensitivity characteristics of ritonavir sulfate, it was i...Ritonavir sulfate is a protease inhibitor widely used in the treatment of acquired immunodeficiency syndrome. In order to elucidate the inherent stability and sensitivity characteristics of ritonavir sulfate, it was investigated under forced thermal and hydration stress conditions as recommended by the Inter- national Conference on Harmonization guidelines. In addition, competency of vibrational （infrared and Raman） spectroscopy was assessed to identify structural changes of the drug symbolizing its stress degradation. High performance liquid chromatography was used as a confirmatory technique for both thermal and hydration stress study, while thermogravimetric analysis]differential thermal analysis and atomic force microscopy substantiated the implementation of vibrational spectroscopy in this frame- work. The results exhibited high thermal stability of the drug as significant variations were observed in the diffuse reflectance infrared Fourier transform spectra only after the drug exposure to thermal radiations at 100 ℃. Hydration behavior of ritonavir sulfate was evaluated using Raman spectroscopy and the value of critical relative humidity was found to be 〉 67%. An important aspect of this study was to utilize vibrational spectroscopic technique to address stability issues of pharmacological molecules, not only for their processing in pharmaceutical industry, but also for predicting their shelf lives and suitable storage conditions.展开更多
Trace metals associated with PM10 aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested5 PCs,which accounted for 86.8% cu...Trace metals associated with PM10 aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested5 PCs,which accounted for 86.8% cumulative variance. PC1 accounted for 30% with a significant loading of metals of anthropogenic origin,while PC2 showed 28% variance with the loading of metals of crustal origin. These trace metals showed seasonal distinct day and night time characteristics. The concentrations of Cu,Pb,and Cd were found to be higher during nighttime in all the seasons. Only Fe was observed with significantly higher mean concentrations during daytime of all seasons except monsoon. The highest mean values of Cu,Cd,Zn,and Pb during post-monsoon might be attributed to winds advection over the regions of waste/biomass burning and industrial activities in Punjab and Haryana regions.Furthermore,concentration weighted trajectory analysis suggested that metals of crustal origin were contributed by long-range transport while metals of anthropogenic and industrial activities were contributed by regional/local source regions.展开更多
In the contemporary days, non-linear optical materials(NLO) are getting higher attention as per the increasing demand in optical communication and data storage technology. Consequently, they explore various physical p...In the contemporary days, non-linear optical materials(NLO) are getting higher attention as per the increasing demand in optical communication and data storage technology. Consequently, they explore various physical properties of the NLO material for their industrial applications. In current report, l-arginine p-nitrobenzoate monohydrate(LANB) single crystals were obtained by adopting slow cooling technique. The structural confirmation of grown single crystal was carried out using single crystal X-Ray diffractometer. Presence of strain within single crystal was deduced using Hall–Williamson relation. Various defects associated within single crystal were assessed using high resolution XRD. Additionally, its crystalline quality was again confirmed by time resolved photoluminescence spectroscopy(TRPL). Using transmission spectra, the cut off wavelength and band gap of the host material was determined to be nearly 420 nm and 2.9 e V respectively. The dielectric property has been recorded by varying the frequency ranging from 50 Hz to 100 k Hz. The curve suggests that dielectric loss value is less at high frequency ensures the suitability of crystal in photonics and NLO based devices.The laser damage threshold values were also measured for single and multiple shots. Thermal parameters of the titled compound were calculated using PPE. In photoconductivity measurement, negative photoconductivity has been observed in titled compound. Microhardness studies were also performed on single crystal to explore its mechanical properties.展开更多
In-situ growth of CdS nanorods (NRs) has been demonstrated via solvothermal, in a low band gap polymer, poly [[4,8-bis[(2-ethylhexyl)oxy] benzo [1,2-b:4,5-b’] dithiophene-2,6-diyl] [3-fluoro-2-[(2-ethylhexyl) carbony...In-situ growth of CdS nanorods (NRs) has been demonstrated via solvothermal, in a low band gap polymer, poly [[4,8-bis[(2-ethylhexyl)oxy] benzo [1,2-b:4,5-b’] dithiophene-2,6-diyl] [3-fluoro-2-[(2-ethylhexyl) carbonyl] thieno [3,4-b] thiophenediyl]] (PTB7). It is a high yielding, green approach as it removes use of volatile and hazardous chemicals such as pyridine as ligand which are conventionally used to synthesize precursors of CdS (NRs). Moreover the solvothermal process is a zero emission process being a close vessel synthesis and hence no material leaching into the atmosphere during the synthesis. The PTB7:CdS nanocomposite has been characterized by SEM, XRD, FTIR, UV-visible spectroscopy techniques. The photoluminescence (PL) spectroscopy study of PTB7 with CdS NRs has shown significant PL quenching by the incorporation of CdS NRs in PTB7;this shows that CdS NRs are efficient electron acceptors with the PTB7. The PTB7:CdS is used as active layer in the fabrication of hybrid solar cells (HSC) as donor-acceptor combination in the bulk heterojunction (BHJ) geometry. The HSCs fabricated using this active layer without any additional supporting fullerene based electron acceptor has given power conversion efficiency of above 1%.展开更多
Tin and its derivatives are extensively used in modern technology tools which lead requirement for development of green methods for its waste management and profitable recycling. Presence of tin in water bodies causes...Tin and its derivatives are extensively used in modern technology tools which lead requirement for development of green methods for its waste management and profitable recycling. Presence of tin in water bodies causes enormous environmental concern due to its acute toxicity to living beings. We demonstrate a simple and zero emission process for extraction of tin ions from aqueous solution using dithiocarbamate-based copolymer and its single step quantitative recovery and transformation into SnS nanoparticles. The polymer shows high metal extraction capacity, 1.06 g SnCl2 per gram of polymer. The polymer metal composite and SnS nanoparticles are analyzed using TEM, FTIR, XRD spectroscopy techniques. The FTIR shows formation of Sn-S bonding in the polymer metal composite. This study has implication for cost effective and green approach for purification of water and waste management.展开更多
We propose a new ion-trap geometry to carry out accurate measurements of the quadrupole shifts in the （171）Yb ion.This trap will minimize the quadrupole shift due to the harmonic component of the confining potential...We propose a new ion-trap geometry to carry out accurate measurements of the quadrupole shifts in the （171）Yb ion.This trap will minimize the quadrupole shift due to the harmonic component of the confining potential by an order of magnitude.This will be useful to reduce the uncertainties in the clock frequency measurements of the 6s 2S（1/2）→4f（13）6s2 2F（7/2）and 6s 2S（1/2）→5d2D（3/2） transitions,from which we can deduce the precise values of the quadrupole moments（0s） of the 4f（13）6s2 2F（7/2） and 5d2D（3/2） states.Moreover,it may be able to affirm the validity of the measured 0 value of the4f（13）6s22F（7/2） state,for which three independent theoretical studies defer almost by one order of magnitude from the measurement.We also calculate 0s using the relativistic coupled-cluster（RCC） method.We use these 0 values to estimate the quadrupole shift that can be measured in our proposed ion trap experiment.展开更多
Crop phenotyping plays a critical role in precision agriculture by enabling the accurate assessment of plant traits,supporting improved crop management,breeding programs,and yield optimization.However,cowpea leaves pr...Crop phenotyping plays a critical role in precision agriculture by enabling the accurate assessment of plant traits,supporting improved crop management,breeding programs,and yield optimization.However,cowpea leaves present unique challenges for automated phenotyping due to their diverse shapes,complex vein structures,and variations caused by environmental conditions.This research presents a deep learning-based approach for the classification of cowpea leaf images to support crop phenotyping tasks.Given the limited availability of annotated datasets,data augmentation techniques were employed to artificially expand the original small dataset while preserving essential leaf characteristics.Various image processing methods were applied to enrich the dataset,ensuring better feature representation without significant information loss.A deep neural network,specifically the MobileNet architecture,was utilized for its efficiency in capturing multi-scale features and handling image data with limited computational resources.The performance of the model trained on the augmented dataset was evaluated,achieving an accuracy of 94.12%on the cowpea leaf classification task.These results demonstrate the effectiveness of data augmentation in enhancing model generalization and learning capabilities.展开更多
Gallium nitride(GaN)nanostructures are highly promising for photoelectrochemical(PEC)water splitting due to their excellent electron mobility,chemical stability,and large surface area.However,the wide bandgap(~3.4 eV)...Gallium nitride(GaN)nanostructures are highly promising for photoelectrochemical(PEC)water splitting due to their excellent electron mobility,chemical stability,and large surface area.However,the wide bandgap(~3.4 eV)of GaN limits its ability to absorb a broad spectrum of solar radiation,restricting its PEC performance.To address this limitation,MoS_(2)/GaN nanorods(NRs)heterostructures for enhanced PEC applications were fabricated on thin tungsten foil using a combination of atmospheric pressure chemical vapor deposition(CVD)and laser molecular beam epitaxy(LMBE).The Raman spectroscopy and X-ray diffraction revealed the hexagonal phase of GaN and MoS_(2).X-ray photoelectron spectroscopy examined the electronic states of the GaN and MoS_(2).PEC measurements revealed that the MoS_(2)-decorated GaN NRs exhibited a photocurrent density of approximately172μA/cm_(2),nearly 2.5-fold compared to bare GaN NRs(~70μA/cm_(2)).The increased photocurrent density is ascribed to the Type II band alignment between MoS_(2)and GaN,which promotes effective charge separation,the decrease in charge transfer resistance,and the increase in active sites.The findings of this work underscore that the CVD and LMBE technique fabricated MoS_(2)/GaN heterostructures on W metal foil substrate can provide the vital strategy to raise the PEC efficiency toward solar water splitting.展开更多
ZrCoSb based half-Heusler(HH)alloys have been widely studied as a p-type thermoelectric(TE)material for power generation applications in the mid-temperature regime.However,their intrinsically high thermal conductivity...ZrCoSb based half-Heusler(HH)alloys have been widely studied as a p-type thermoelectric(TE)material for power generation applications in the mid-temperature regime.However,their intrinsically high thermal conductivity has been found to be detrimental for the improvement in their thermoelectric figure-of-merit(ZT),which presently is far below unity.In the current work,a state-of-the-art ZT~1.1 at 873 K was realized in an optimized composition of nanostructured Zr1-xHfxCoSb_(0.9)Sn_(0.1) HH alloys by employing compositional modulation i.e.grain-by-grain compositional variations,which leads to a substantial increase in its power factor coupled with a concurrent decrease in its thermal conductivity.Significant reduction in the phonon mean-free-path is observed on Hf substitution,which is comparable to the average crystallite size(~25 nm),thus leading to a very low thermal conductivity of~2.2Wm^(-1)K^(-1) at 873 K,which is amongst the lowest reported in HH alloys.The TE device characteristics,estimated using cumulative temperature dependence model for quantitative evaluation of TE performance,yielded an output power density of~10 Wcm2 with a leg efficiency of~10%in the optimized composition of nanostructured Zr_(1-x)Hf_(x)CoSb_(0.9)Sn_(0.1) HH alloys,which is comparable to the reported efficiencies of other state-of-the-art TE materials.展开更多
Recently developed lead-free double perovskite nanocrystals(NCs)have been proposed for the possible application in solutionprocessed optoelectronic devices.However,the optoelectronic applications of double perovskite ...Recently developed lead-free double perovskite nanocrystals(NCs)have been proposed for the possible application in solutionprocessed optoelectronic devices.However,the optoelectronic applications of double perovskite NCs have been hampered due to the structural and chemical instability in the presence of polar molecules.Here,we report a facile strategy for the synthesis and purification of Cs_(2)AgBiBr_(6)double perovskite NCs that remained stable even after washing with polar solvent.This is realized with our efficient colloidal route to synthesize Cs_(2)AgBiBr_(6)NCs that involve stable and strongly coordinated precursor such as silvertrioctyl phosphine complex together with bismuth neodecanoate,which leads to a significantly improved chemical and colloidal stability.Using layer-by-layer solid-state ligand exchange technique,a compact and crack-free thin film of Cs_(2)AgBiBr_(6)NCs were fabricated.Finally,perovskite solar cells consisting of Cs_(2)AgBiBr_(6)as an absorber layer were fabricated and tested.展开更多
文摘In this research work, atomic and molecular orbitals based analysis has been made to see electronic structure of platinum halides (platinum dichloride, platinum dibromide, platinum diiodide and platinum difluride). The geometry optimization and three dimensional (3D) modeling of the above mentioned species have been made on CAChe pro software. The results show: (i) The involvement of three p atomic orbitals is negligible as their summation values are very low in comparison to d orbital and considerably low with respect to s orbital. (ii) The study well support the Landis concepts of sdn-hybridation (here n = 1) as bond angle and contributions of s-orbital and d-orbital of Pt(II) are maximum with negligible contribution of p-orbitals. (iii) These halides also support the cloud-expanding effect with experimental data and also follow the nephelauxetic effect. The result is in good agreement with experiment results that covalent character increases in the order: PtI2 > PtBr2 > PtCl2 > PtF2. (iv) And thus the study will help to fine tune the existing complexes of these halides.
基金supported by Council of Scientific and Industrial Research(CSIR)under its network project(CSIR-NWP-51)entitled"Nanostructured Advanced Materials(NAM)"
文摘AI 5083//10 wt% SiCp nano composites have been synthesized by means of high energy ball milling followed by spark plasma sintering （SPS）. Nano composites produced via this method exhibited near-theoretical density while retaining the nano-grained features. X-ray diffraction （XRD） analysis indicated that the crystalline size of the ball milled AI 5083 matrix was observed to be～25 nm and it was coarsened up to～30 nm after SPS. Nano indentation results of nano composites demonstrated a high hardness of～280 HV with an elastic modulus of 126 GPa. Wear and friction characteristics with addition of SiCp reinforcement exhibited significant improvement in terms of coefficient of friction and specific wear rate to that of nano structured AI 5083 alloy. The reduction in specific wear rate in the nanocomposite was mainly due to the change of wear mechanism from adhesive to abrasive wear with the addition of SiCp which resulted in high hardness associated with nano-grained microstructure.
文摘Nano silver （Agn） is employed as an active antimicrobial agent, but the environmental impact of Agn released from commercial products is unknown. The quantity of nanomaterial released from consumer products during use should be determined to assess the environmental risks of advancement of nanotechnology. This work investigated the amount of silver released from three different types of fabric into water during washing. Three different types of fabric were loaded with chemically synthesized Ag nanoparticles and washed repeatedly under simulated washing conditions. Variable leaching rates among fabric types suggest that the manufacturing process may control the release of silver reaching the waste water treatment plants. In an attempt to recover the Agn for reutilization and to save it from polluting water, the effluents from the wash were efficiently treated with bacterial strains. This treatment was based on biosorption and was very efficient for the elimination of silver nanoparticles in the wash water. The process ensured the recovery of the Agn leached into the effluent for reutilization, thus preventing environmental repercussions.
文摘We report an electrodeposited poly(pyrrole-co-pyrrolepropylic acid) copolymer modified electroactive graphene-carbon nanotubes composite deposited on a glassy carbon electrode to detect the protein antigen(cTnI). The copolymer provides pendant carboxyl groups for the site-specific covalent immobilization of protein antibody, antitroponin I. The hybrid nanocomposite was used as a transducer for biointerfacial impedance sensing for cTnI detection.The results show that the hybrid exhibits a pseudo capacitive behaviour with a maximum phase angle of 49° near 1 Hz,which is due to the inhomogeneous and porous structure of the hybrid composition. The constant phase element of copolymer is 0.61(n = 0.61), whereas, it is 0.88(n = 0.88) for the hybrid composites, indicating a comparatively homogeneous microstructure after biomolecular functionalization. The transducer shows a linear change in charge transfer characteristic(R_(et)) on cTnI immunoreaction for spiked human serum in the concentration range of 1.0 pg mL^(-1)–10.0 ng mL^(-1). The sensitivity of the transducer is 167.8 ± 14.2 Ω cm^2 per decade, and it also exhibits high specificity and good reproducibility.
基金Council of Scientific and Industrial Research(CSIR)for providing the fellowship under CSIR-SRF scheme(P81101)。
文摘Vehicular emissions are considered one of the major anthropogenic sources of greenhouse gases and poor air quality in metropolitan cities.This study aims to see the correlation of CO_(2),CH_(4),and CO through monitoring over a period from December 2020 to October 2021 covering three seasons’winter,summer,and monsoon at two different traffic locations of Delhi having different traffic volumes,road patterns,and traffic management.The annual average morning concentration of CO_(2),CH_(4)and CO was found(533±105),(7.3±3.1),(10.7±3.0)ppm at Najafgarh and(480±70),(5.2±1.8),(7.8±2.8)ppm at Rajendra Place,respectively.A relationship between concentration of all three gases and meteorological parameters such as temperature,humidity,wind speed and wind direction has also been investigated using Pearson correlation coefficient and pollution rose diagram.A comparable pattern in concentration was observed for all three gases in spatial(location)and temporal(diurnal)distribution.The concentration trend of CO_(2)in different seasons is winter>summer>monsoon,while in the case of CH_(4)winter=summer>monsoon but not any seasonal trend was noted in CO case.It is observed that CO_(2)has a good relation with CO(a tracer for vehicular emission)in terms of diurnal variation,whereas,CH_(4)does not represent a relation with CO and CO_(2)diurnally,suggesting that vehicles are the source of CO_(2)but not much contributing to other greenhouse gases like CH_(4).
文摘Novel and simplified bi-layer top-emitting white organic light emitting diodes(OLEDs)with dual co-host emitters have been simulated and analyzed.They consist of yellow-green emitting layer(EML)as electron transport layer(ETL)and blue EML as hole transport layer(HTL).Novelty of the device lies in simplification of tri-layer white OLED to a bi-layered device which is done by merging yellow-green EML with ETL and blue EML with HTL.The simulated devices show Commission Internationale de L’Eclairage(CIE)colour coordinates well within the emission range of white light.The results show that device A with 5,6,11,12-tetraphenylnaphthacene(rubrene)doped ETL has achieved the lowest luminance but longest excited state lifetime.Device D with tris-(8-hydroxyquinoline)aluminum:4-(dicyanomethylene)-2-t-butyle-6-(1,1,7,7-tetra-methyljulolidyl-9-enyl)4 H-pyran(Alq3:DCJTB)as ETL which emits yellow light and 2,7-bis[N,N-bis(4-methoxy-phenyl)amino]-9,9-spirobifluorene(MS-TPD):bis(2-methyl-8-quninolinato)-4-phenylphenolate alu-minium(BAlq)as HTL which is responsible for blue light emission is found to have best characteristics when compared to other simulated devices.It has a maximum luminance of 10000 cd/m2 and current efficiency of 15.25 cd/A,respectively,and CIE coordinates are at(0.329,0.319).The device is found to be compatible to be used in solid state lighting applications because of the low driving voltage of the device.
基金U.G.C New Delhi for the financial support through JRF(No.116459)
文摘The present study highlights the potential application of zinc peroxide （ZnO2） nanomaterial as an efficient material for the decontamination of cyanide from contaminated water. A process patent for ZnO2 synthesis has been granted in United States of America （US Patent number 8,715,612; May 2014）, South Africa, Bangladesh, and India. The ZnO2 nanomaterial was capped with polyvinylpyrrolidone （PVP） to control the particle size. The PVP capped ZnO2 nanomaterial （PVP-ZnO2） before and after adsorption of cyanide was characterized by scanning electron microscope, transmission electron microscope, X-ray diffractorneter, Fourier transform infrared spectroscopy and time of flight-secondary ion mass spectrom- etry. The remaining concentration of cyanide after adsorption by PVP-ZnO2 was determined using ion chromatograph. The adsorption of cyanide over PVP-ZnO2 was also studied as a function of pH, adsorbent dose, time and concentration of cyanide. The maximum removal of cyanide was observed in pH range 5.8-7.8 within 15 rain. The adsorption data was fitted to Langmuir and Fruendlich isotherm and it has been observed that data follows both the isotherms and also follows second order kinetics.
文摘Recognizing the composition and modulation of the microbiome, a viable therapeutic tool for multi-targeted therapy is a new strategy that has recently been explored. Glucosamine (GS) is being studied for its prebiotic potential in addition to being the most abundant and naturally occurring amino monosaccharide. The current study focuses on glucosamine’s prebiotic potential by assessing the stability of various GS concentrations (1% - 5%) in the gastrointestinal tract (GIT) and its ability to be fermented by the gut microbiota. The results showed that GS stimulated the most growth in L. acidophilus even after a longer incubation time than B. bifidum and L. acidophilus growth was concentration-dependent, with maximum growth at 3% with a simultaneous decrease in pH (5.6 - 1.7). The decrease in GS concentration with time also represented the growth of bacterial species, demonstrating the species’ utilization of GS. Furthermore, at 3%, GS also represented the prebiotic index of 1.9. In addition, the concentration of GS in various simulated GIT fluids was estimated in both fast and fed conditions to examine GS stability at various levels in the gut. The results showed that GS remained unaffected and non-digestible in all of the simulated GIT fluids (salivary, gastric, intestinal, and colonic), but there was a slight decrease in GS concentration (2.8%) in the fasted state of gastric fluid due to low pH levels (1.6). As a result, the findings are conclusive and suggest that GS possesses prebiotic properties.
文摘The coal is contaminated with toxic metals at the trace levels. They are released into the environment during mining, handling and burning of coal. The Korba basin has one of the largest coal exploitation areas in the country. In this work, contamination and sources of toxic metals i.e. Hg and Pb in the air, soil and sediment of the Korba basin, India are described. The concentration of Hg and Pb in the ambient air was ranged from 7.4 - 29 and 7.0 - 585 ng/m3 with mean value of 18 ± 4 and 129 ± 104 ng/m3 in the winter season. The mean concentration of Hg in the soil and sediment was 0.22 ± 0.03 and 0.44 ± 0.08 mg/kg, respectively. The higher concentration of Pb in the environmental samples was observed.
文摘Ritonavir sulfate is a protease inhibitor widely used in the treatment of acquired immunodeficiency syndrome. In order to elucidate the inherent stability and sensitivity characteristics of ritonavir sulfate, it was investigated under forced thermal and hydration stress conditions as recommended by the Inter- national Conference on Harmonization guidelines. In addition, competency of vibrational （infrared and Raman） spectroscopy was assessed to identify structural changes of the drug symbolizing its stress degradation. High performance liquid chromatography was used as a confirmatory technique for both thermal and hydration stress study, while thermogravimetric analysis]differential thermal analysis and atomic force microscopy substantiated the implementation of vibrational spectroscopy in this frame- work. The results exhibited high thermal stability of the drug as significant variations were observed in the diffuse reflectance infrared Fourier transform spectra only after the drug exposure to thermal radiations at 100 ℃. Hydration behavior of ritonavir sulfate was evaluated using Raman spectroscopy and the value of critical relative humidity was found to be 〉 67%. An important aspect of this study was to utilize vibrational spectroscopic technique to address stability issues of pharmacological molecules, not only for their processing in pharmaceutical industry, but also for predicting their shelf lives and suitable storage conditions.
基金Partial financial support from the CSIR network project(PSC 0112)CSIR fellowship to Subhash Chandra,SRF
文摘Trace metals associated with PM10 aerosols and their variation during day and nighttime as well as during different seasons have been studied for the year 2012. PCA analysis suggested5 PCs,which accounted for 86.8% cumulative variance. PC1 accounted for 30% with a significant loading of metals of anthropogenic origin,while PC2 showed 28% variance with the loading of metals of crustal origin. These trace metals showed seasonal distinct day and night time characteristics. The concentrations of Cu,Pb,and Cd were found to be higher during nighttime in all the seasons. Only Fe was observed with significantly higher mean concentrations during daytime of all seasons except monsoon. The highest mean values of Cu,Cd,Zn,and Pb during post-monsoon might be attributed to winds advection over the regions of waste/biomass burning and industrial activities in Punjab and Haryana regions.Furthermore,concentration weighted trajectory analysis suggested that metals of crustal origin were contributed by long-range transport while metals of anthropogenic and industrial activities were contributed by regional/local source regions.
文摘In the contemporary days, non-linear optical materials(NLO) are getting higher attention as per the increasing demand in optical communication and data storage technology. Consequently, they explore various physical properties of the NLO material for their industrial applications. In current report, l-arginine p-nitrobenzoate monohydrate(LANB) single crystals were obtained by adopting slow cooling technique. The structural confirmation of grown single crystal was carried out using single crystal X-Ray diffractometer. Presence of strain within single crystal was deduced using Hall–Williamson relation. Various defects associated within single crystal were assessed using high resolution XRD. Additionally, its crystalline quality was again confirmed by time resolved photoluminescence spectroscopy(TRPL). Using transmission spectra, the cut off wavelength and band gap of the host material was determined to be nearly 420 nm and 2.9 e V respectively. The dielectric property has been recorded by varying the frequency ranging from 50 Hz to 100 k Hz. The curve suggests that dielectric loss value is less at high frequency ensures the suitability of crystal in photonics and NLO based devices.The laser damage threshold values were also measured for single and multiple shots. Thermal parameters of the titled compound were calculated using PPE. In photoconductivity measurement, negative photoconductivity has been observed in titled compound. Microhardness studies were also performed on single crystal to explore its mechanical properties.
文摘In-situ growth of CdS nanorods (NRs) has been demonstrated via solvothermal, in a low band gap polymer, poly [[4,8-bis[(2-ethylhexyl)oxy] benzo [1,2-b:4,5-b’] dithiophene-2,6-diyl] [3-fluoro-2-[(2-ethylhexyl) carbonyl] thieno [3,4-b] thiophenediyl]] (PTB7). It is a high yielding, green approach as it removes use of volatile and hazardous chemicals such as pyridine as ligand which are conventionally used to synthesize precursors of CdS (NRs). Moreover the solvothermal process is a zero emission process being a close vessel synthesis and hence no material leaching into the atmosphere during the synthesis. The PTB7:CdS nanocomposite has been characterized by SEM, XRD, FTIR, UV-visible spectroscopy techniques. The photoluminescence (PL) spectroscopy study of PTB7 with CdS NRs has shown significant PL quenching by the incorporation of CdS NRs in PTB7;this shows that CdS NRs are efficient electron acceptors with the PTB7. The PTB7:CdS is used as active layer in the fabrication of hybrid solar cells (HSC) as donor-acceptor combination in the bulk heterojunction (BHJ) geometry. The HSCs fabricated using this active layer without any additional supporting fullerene based electron acceptor has given power conversion efficiency of above 1%.
文摘Tin and its derivatives are extensively used in modern technology tools which lead requirement for development of green methods for its waste management and profitable recycling. Presence of tin in water bodies causes enormous environmental concern due to its acute toxicity to living beings. We demonstrate a simple and zero emission process for extraction of tin ions from aqueous solution using dithiocarbamate-based copolymer and its single step quantitative recovery and transformation into SnS nanoparticles. The polymer shows high metal extraction capacity, 1.06 g SnCl2 per gram of polymer. The polymer metal composite and SnS nanoparticles are analyzed using TEM, FTIR, XRD spectroscopy techniques. The FTIR shows formation of Sn-S bonding in the polymer metal composite. This study has implication for cost effective and green approach for purification of water and waste management.
基金CSIR-National Physical Laboratory,Depaitment of Science and Technology(Grant No.SB/S2/LOP/033/2013)the Board of Research in Nuclear Sciences(Grant No. 34/14/ 19/2014-BRNS/0309) for supporting
文摘We propose a new ion-trap geometry to carry out accurate measurements of the quadrupole shifts in the （171）Yb ion.This trap will minimize the quadrupole shift due to the harmonic component of the confining potential by an order of magnitude.This will be useful to reduce the uncertainties in the clock frequency measurements of the 6s 2S（1/2）→4f（13）6s2 2F（7/2）and 6s 2S（1/2）→5d2D（3/2） transitions,from which we can deduce the precise values of the quadrupole moments（0s） of the 4f（13）6s2 2F（7/2） and 5d2D（3/2） states.Moreover,it may be able to affirm the validity of the measured 0 value of the4f（13）6s22F（7/2） state,for which three independent theoretical studies defer almost by one order of magnitude from the measurement.We also calculate 0s using the relativistic coupled-cluster（RCC） method.We use these 0 values to estimate the quadrupole shift that can be measured in our proposed ion trap experiment.
文摘Crop phenotyping plays a critical role in precision agriculture by enabling the accurate assessment of plant traits,supporting improved crop management,breeding programs,and yield optimization.However,cowpea leaves present unique challenges for automated phenotyping due to their diverse shapes,complex vein structures,and variations caused by environmental conditions.This research presents a deep learning-based approach for the classification of cowpea leaf images to support crop phenotyping tasks.Given the limited availability of annotated datasets,data augmentation techniques were employed to artificially expand the original small dataset while preserving essential leaf characteristics.Various image processing methods were applied to enrich the dataset,ensuring better feature representation without significant information loss.A deep neural network,specifically the MobileNet architecture,was utilized for its efficiency in capturing multi-scale features and handling image data with limited computational resources.The performance of the model trained on the augmented dataset was evaluated,achieving an accuracy of 94.12%on the cowpea leaf classification task.These results demonstrate the effectiveness of data augmentation in enhancing model generalization and learning capabilities.
基金funded by the CSIR-FIRST(MLP211732)SAMMARTH(HCP-55).
文摘Gallium nitride(GaN)nanostructures are highly promising for photoelectrochemical(PEC)water splitting due to their excellent electron mobility,chemical stability,and large surface area.However,the wide bandgap(~3.4 eV)of GaN limits its ability to absorb a broad spectrum of solar radiation,restricting its PEC performance.To address this limitation,MoS_(2)/GaN nanorods(NRs)heterostructures for enhanced PEC applications were fabricated on thin tungsten foil using a combination of atmospheric pressure chemical vapor deposition(CVD)and laser molecular beam epitaxy(LMBE).The Raman spectroscopy and X-ray diffraction revealed the hexagonal phase of GaN and MoS_(2).X-ray photoelectron spectroscopy examined the electronic states of the GaN and MoS_(2).PEC measurements revealed that the MoS_(2)-decorated GaN NRs exhibited a photocurrent density of approximately172μA/cm_(2),nearly 2.5-fold compared to bare GaN NRs(~70μA/cm_(2)).The increased photocurrent density is ascribed to the Type II band alignment between MoS_(2)and GaN,which promotes effective charge separation,the decrease in charge transfer resistance,and the increase in active sites.The findings of this work underscore that the CVD and LMBE technique fabricated MoS_(2)/GaN heterostructures on W metal foil substrate can provide the vital strategy to raise the PEC efficiency toward solar water splitting.
基金the Board of Research in Nuclear Sciences,India for the financial support under the Scheme:37(3)/14/22/2016-BRNS with BSC.Nagendra S.Chauhan acknowledges CSIR-Senior Research Fellowship.(Grant No:31/001(0430)/2014-EMR-1)The technical support rendered by Dr.Vidya Nand Singh,Mr.Radhey Shyam,and Mr.Naval Kishor Upadhyay is also gratefully acknowledged.
文摘ZrCoSb based half-Heusler(HH)alloys have been widely studied as a p-type thermoelectric(TE)material for power generation applications in the mid-temperature regime.However,their intrinsically high thermal conductivity has been found to be detrimental for the improvement in their thermoelectric figure-of-merit(ZT),which presently is far below unity.In the current work,a state-of-the-art ZT~1.1 at 873 K was realized in an optimized composition of nanostructured Zr1-xHfxCoSb_(0.9)Sn_(0.1) HH alloys by employing compositional modulation i.e.grain-by-grain compositional variations,which leads to a substantial increase in its power factor coupled with a concurrent decrease in its thermal conductivity.Significant reduction in the phonon mean-free-path is observed on Hf substitution,which is comparable to the average crystallite size(~25 nm),thus leading to a very low thermal conductivity of~2.2Wm^(-1)K^(-1) at 873 K,which is amongst the lowest reported in HH alloys.The TE device characteristics,estimated using cumulative temperature dependence model for quantitative evaluation of TE performance,yielded an output power density of~10 Wcm2 with a leg efficiency of~10%in the optimized composition of nanostructured Zr_(1-x)Hf_(x)CoSb_(0.9)Sn_(0.1) HH alloys,which is comparable to the reported efficiencies of other state-of-the-art TE materials.
文摘Recently developed lead-free double perovskite nanocrystals(NCs)have been proposed for the possible application in solutionprocessed optoelectronic devices.However,the optoelectronic applications of double perovskite NCs have been hampered due to the structural and chemical instability in the presence of polar molecules.Here,we report a facile strategy for the synthesis and purification of Cs_(2)AgBiBr_(6)double perovskite NCs that remained stable even after washing with polar solvent.This is realized with our efficient colloidal route to synthesize Cs_(2)AgBiBr_(6)NCs that involve stable and strongly coordinated precursor such as silvertrioctyl phosphine complex together with bismuth neodecanoate,which leads to a significantly improved chemical and colloidal stability.Using layer-by-layer solid-state ligand exchange technique,a compact and crack-free thin film of Cs_(2)AgBiBr_(6)NCs were fabricated.Finally,perovskite solar cells consisting of Cs_(2)AgBiBr_(6)as an absorber layer were fabricated and tested.
