Predominant Peak Research Articles

Square-Wave and Cyclic Voltammetry of Native Proanthocyanidins Extracted from Grapevine (Vitis vinifera) on the Glassy Carbon Electrode

Condensed tannins are short polymers of flavan-3-ols found in grapes (also known as proanthocyanidins). An investigation on the electrochemical oxidation of grapevine proanthocyanidins (PAs) on glassy carbon electrodes under various conditions was conducted for the first time. To study how the proanthocyanidins were oxidized, square-wave and cyclic voltammetry were used. There is a predominant oxidation peak associated with the extract of proanthocyanidins, and this can be attributed to the oxidation of catechol 3′,4′-dihydroxyl groups, which can form their oxidation peak. There are two electrons and two protons involved in the oxidation of the catechol group, which must be kept in mind when considering the oxidation of the catechol group. On the glassy carbon electrode (GCE), the PAs extracted from grapevine are oxidized by an adsorption-dependent mechanism as they interact with the GCE surface. As a result, it was found that the anodic peak current varied linearly with PAs’ concentrations in the range of 4 to 50 ppm, with a detection limit of 3.07 ppm (S/N = 3). There was a development in the surface concentration of the oxidation products at the GC electrode; as the scans progressed, the surface concentration of oxidation products at the electrode remained at 4.83 × 10−11 mol cm−2, indicating that they were immobilized on the GCE as oxidation products adsorbed on the electrode.

Cobalt nanoparticles synthesizing potential of orange peel aqueous extract and their antimicrobial and antioxidant activity

The ability of cobalt nanoparticles (CoNPs) to absorb electromagnetic waves led to their use as potential biomedical agents in recent years. The properties of magnetic fluid containing cobalt nanoparticles are extraordinary. Hence, this research was designed to evaluate the Co(NO3)2 reducing the potential of orange peel aqueous extract and assessed their antimicrobial and antioxidant activities. The aqueous extract derived from orange peel had the potential to fabricate the CoNPs from 1 M Co(NO3)2 and the synthesized CoNPs were successfully characterized by standard nanoparticles characterization techniques such as UV–vis spectrophotometer, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), and Dynamic light scattering (DLS) analyses. The FTIR analysis revealed that the synthesized CoNPs were capped with active functional groups. It was characterized by predominant peaks corresponding to carbonyl (CO), amide (CO = ), and C–O of alcohols or phenols. The size and shape of CoNPs were found as 14.2–22.7 nm and octahedral, respectively, under SEM analysis. Furthermore, at increased concentration, the CoNPs demonstrated remarkable antimicrobial activity against common bacterial (Escherichia coli, Staphylococcus aureus,Bacillus subtilis, and Klebsiella pneumoniae) and fungal (Aspergillus niger) pathogens. Furthermore, these CoNPs also showed considerable in-vitro antioxidant activities against various free articles such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), and Hydrogen Peroxide (H2O2). These results suggest that OP aqueous extract synthesized CoNPs possess considerable biomedical applications.

Interactions between upstream-propagating guided jet waves and shear-layer instability waves near the nozzle of subsonic and nearly ideally expanded supersonic free jets with laminar boundary layers

The interactions between upstream-propagating guided jet waves and shear-layer instability waves near the nozzle of subsonic and nearly ideally expanded supersonic, isothermal free jets are investigated for jets at Mach numbers between 0.50 and 2 with fully laminar exit boundary layers of different thicknesses. The velocity spectra in the shear layers downstream of the nozzle exhibit strong narrow peaks for the first azimuthal modes, associated with growing Kelvin–Helmholtz instability waves. The frequencies of the predominant peaks are close, but not necessarily equal, to those of the most amplified instability waves predicted from the mean flow fields using linear stability analysis. They also fall in most cases within or very near the allowable frequency bands of the free-stream upstream-propagating guided jet waves obtained using a vortex-sheet model and jump from one band to another as the Mach number increases. At these frequencies, moreover, high levels organized into elongated stripes are found in the jet potential core and standing-wave patterns are visible at the edges of the shear layers in the power spectral densities of pressure and velocity fluctuations. Therefore, the free-stream upstream-propagating guided jet waves appear to interact with and excite the instability waves near the nozzle of the present jets, as in screeching and impinging jets. This explains the disparities of the frequencies and azimuthal modes of the instability waves dominating early on in the shear layers of initially laminar jets and their discontinuous changes and staging behaviours as the jet velocity varies.

Synthesis of a new Cu2MgGeS4 quaternary compound thin film by a low-cost spray method: Structural, Raman and optical properties

• Cu 2 MgGeS 4 thin film was synthesized for the first time. • Tetragonal kesterite structure was confirmed. • Raman measurement was conducted for the first time for Cu 2 MgGeS 4. • An optical band gap of 1.80 eV was obtained. In this work, the new Cu 2 MgGeS 4 quaternary compound thin film was synthesized for the first time by spray-ultrasonic of Cu–Mg–Ge precursors onto glass-substrate followed by a sulfurization for 1 h at 500 °C. The EDX Mapping shows a uniform desitribution of Cu–Mg–Ge–S with a value near to the ideal stoichiometry of 2:1:1:4 of Cu 2 MgGeS 4 . X-ray diffraction displaying typical peaks relating to (1 1 2), (0 0 4), (1 0 5), (2 2 0) and (3 1 2)/(1 1 6) planes of the tetragonal kesterite Cu 2 MgGeS 4 phase ( I 4 ¯ ), the result was confirmed by the presence of all characteristic Raman peak of kesterite structure, especially the predominant peak at (361 cm −1 ). The optical-gap is around 1.80 eV with a high absorption in the visible solar range. These achievements make this new material a potential candidate for solar conversion applications.

Swift Heavy Ion-Induced Reactivity and Surface Modifications in Indium Thin Films.

As an energetic ion traverses a target material, it loses its energy through the processes of electronic energy loss (Se) and nuclear energy loss (Sn). Controlled swift heavy ion (SHI) irradiation on solid targets produces its effects through both of these mechanisms, as a consequence of which modifications occur in the structure, surface morphology, and magnetic and optical properties, apart from ion implantation and ion-induced reactivity. A systematic investigation of these effects can be useful in developing standard protocols for creating desired effects in materials using specific ion beams. In this study, indium films of thickness 25 nm were deposited on silicon substrates and were subjected to 100 MeV O7+ and 100 MeV Si7+ ion irradiation, with the fluences varying from 1 × 1011 to 1 × 1013 ions/cm2. The pristine and SHI-irradiated films were then characterized using glancing incidence X-ray diffraction (GIXRD), Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The motive was to identify the effects of irradiation with different ion species having large variations in electronic and nuclear energy losses. While the RBS results suggest that sputtering is extremely low and that there are no major changes in the film composition due to ion beam-induced mixing, the GIXRD analysis indicates that increasing the ion fluence reduces the crystallinity of the film for both the ions. Ion beam irradiation with O7+ ions, however, results in beam-induced reactivity, as the GIXRD scan shows characteristic peaks from indium oxide (In2O3), which become the predominant peaks at the highest fluence used here. Si7+ ion irradiation results in a narrowing of the particle size distribution on the surface, with no evidence of reactivity. SEM results indicate fusion and fragmentation of grains with the increase in the ion fluences, and AFM images reveal an increase in the surface roughness of a few percent when irradiated with both 100 MeV O7+ and 100 MeV Si7+ ions.

Experimental study of admixture on Bentonite clay reinforced concrete as a partial substitute to cement

The mortar mixtures were prepared in various proportioned with cement to sand ratio of 1:3 and 1:4. The reinforced concretes were cast for the same flow level but different percentages of clay (0, 5, 10 & 15%) dosage. The prepared motor concrete subjected for structural study and mechanical property analysis. In FTIR spectra shows predominant peaks are observed the presence of admixture and clay in the concrete motor. The XRD spectra indicates the formation tetrahedrally arrangement of silicate and octahedrally arrangement of aluminate groups in clay mixed concrete. The surface morphology significantly improved upon adding of different admixture as examined in SEM image. The mechanical study revealed that the compressive strength increases with increase in clay percentages up to C-2 (10 wt %) due to the strong adhesion because of mixture of water reduce and water repellent which makes better compact and reduce porosity. The addition of slump flow improved due to presence of polycarboxylate ether and the evident workability loss started after the resting time of 25 min.

Effects of welding defects on the damage evolution of Q245R steel using acoustic emission and infrared thermography

ABSTRACT Detecting welding defects is a key aspect in the safety assessment of pressure vessels. Using non-destructive testing methods to reveal influences of welding defects on the evolution of material damage is of great significance. In this paper, the damage evolution of Q245R steel with different welding defects was monitored by acoustic emission and infrared thermography technology. First, cluster analysis was used to reduce the effects of noise on acoustic emission signals. Then, differences in the characteristic parameters during the damage evolution were compared. Furthermore, the predominant peak frequency and time-frequency spectrum using fast Fourier transform and wavelet transform were investigated for acoustic emission waveforms, and temperature changes were monitored during damage evolution using thermal conductivity. The results indicated that the effects of different welding defects on the damage evolution of Q245R steel can be effectively revealed through the non-destructive testing technology combining acoustic emission and infrared thermography, which can provide a reference for evaluating the overall structural health of pressure vessels and reducing the failure risk.

Time-Series Analysis for the Number of Foot and Mouth Disease Outbreak Episodes in Cattle Farms in Thailand Using Data from 2010-2020.

Thailand is one of the countries where foot and mouth disease outbreaks have resulted in considerable economic losses. Forecasting is an important warning technique that can allow authorities to establish an FMD surveillance and control program. This study aimed to model and forecast the monthly number of FMD outbreak episodes (n-FMD episodes) in Thailand using the time-series methods, including seasonal autoregressive integrated moving average (SARIMA), error trend seasonality (ETS), neural network autoregression (NNAR), and Trigonometric Exponential smoothing state–space model with Box–Cox transformation, ARMA errors, Trend and Seasonal components (TBATS), and hybrid methods. These methods were applied to monthly n-FMD episodes (n = 1209) from January 2010 to December 2020. Results showed that the n-FMD episodes had a stable trend from 2010 to 2020, but they appeared to increase from 2014 to 2020. The outbreak episodes followed a seasonal pattern, with a predominant peak occurring from September to November annually. The single-technique methods yielded the best-fitting time-series models, including , , , and . Moreover, SARIMA-NNAR and NNAR-TBATS were the hybrid models that performed the best on the validation datasets. The models that incorporate seasonality and a non-linear trend performed better than others. The forecasts highlighted the rising trend of n-FMD episodes in Thailand, which shares borders with several FMD endemic countries in which cross-border trading of cattle is found common. Thus, control strategies and effective measures to prevent FMD outbreaks should be strengthened not only in Thailand but also in neighboring countries.

Molecular Epidemiology of Herpangina Children in Tongzhou District, Beijing, China, During 2019-2020.

BackgroundThe changing pattern of pathogen spectrum causing herpangina in the time of coronavirus disease 2019 (COVID-19) pandemic was unknown. The purpose of this study was to investigate the changes on the molecular epidemiology of herpangina children during 2019-2020 in Tongzhou district, Beijing, China.MethodFrom January 2019 to December 2020, children diagnosed with herpangina were recruited by the staff from Tongzhou Center for Disease Control and Prevention (CDC) in Beijing. Viral RNA extraction from pharyngeal swabs was used for enterovirus (EV) detection and the complete VP1 gene was sequenced. The phylogenetic analysis was performed based on all VP1 sequences for EV genotypes.ResultA total of 1,331 herpangina children were identified during 2019-2020 with 1,121 in 2019 and 210 in 2020, respectively. The predominant epidemic peak of herpangina children was in summer and autumn of 2019, but not observed in 2020. Compared to the number of herpangina children reported in 2019, it decreased sharply in 2020. Among 129 samples tested in 2019, 61 (47.3%) children were detected with EV, while 22.5% (20/89) were positive in 2020. The positive rate for EV increased since June 2019, peaked at August 2019, and decreased continuously until February 2020. No cases were observed from February to July in 2020, and the positive rate of EV rebounded to previous level since August 2020. Four genotypes, including coxsackievirus A6 (CV-A6, 9.3%), CV-A4 (7.8%), CV-A10 (2.3%) and CV-A16 (10.1%), were identified in 2019, and only three genotypes, including CV-A6 (9.0%), CV-A10 (6.7%) and CV-A16 (1.1%), were identified in 2020. The phylogenetic analysis showed that all CV-A6 strains from Tongzhou located in Group C, and the predominant strains mainly located in C2-C4 subgroups during 2016-2018 and changed into C1 subgroup during 2018-2020. CV-A16 strains mainly located in Group B, which consisting of strains widely distributed around the world.ConclusionsThe predominant genotypes gradually shifted from CV-A16, CV-A4 and CV-A6 in 2019 to CV-A6 in 2020 under COVID-19 pandemic. Genotype-based surveillance will provide robust evidence and facilitate the development of public health measures.

Characteristics, source apportionment and long-range transport of black carbon at a high-altitude urban centre in the Kashmir valley, North-western Himalaya

Six years of data (2012–2017) at an urban site-Srinagar in the Northwest Himalaya were used to investigate temporal variability, meteorological influences, source apportionment and potential source regions of BC. The daily BC concentration varies from 0.56 to 40.16 μg/m3 with an inter-annual variation of 4.20–7.04 μg/m3 and is higher than majority of the Himalayan urban locations. High mean annual BC concentration (6.06 μg/m3) is attributed to the high BC observations during winter (8.60 μg/m3) and autumn (8.31 μg/m3) with a major contribution from Nov (13.88 μg/m3) to Dec (13.4 μg/m3). A considerable inter-month and inter-seasonal BC variability was observed owing to the large changes in synoptic meteorology. Low BC concentrations were observed in spring and summer (3.14 μg/m3 and 3.21 μg/m3), corresponding to high minimum temperatures (6.6 °C and 15.7 °C), wind speed (2.4 and 1.6 m/s), ventilation coefficient (2262 and 2616 m2/s), precipitation (316.7 mm and 173.3 mm) and low relative humidity (68% and 62%). However, during late autumn and winter, frequent temperature inversions, shallow PBL (173–1042 m), stagnant and dry weather conditions cause BC to accumulate in the valley. Through the observation period, two predominant diurnal BC peaks were observed at ⁓9:00 h (7.75 μg/m3) and ⁓21:00 h (6.67 μg/m3). Morning peak concentration in autumn (11.28 μg/m3) is ⁓2–2.5 times greater than spring (4.32 μg/m3) and summer (5.23 μg/m3), owing to the emission source peaks and diurnal boundary layer height. Diurnal BC concentration during autumn and winter is 65% and 60% higher than spring and summer respectively. During autumn and winter, biomass burning contributes approximately 50% of the BC concentration compared to only 10% during the summer. Air masses transport considerable BC from the Middle East and northern portions of South Asia, especially the Indo-Gangetic Plains, to Srinagar, with serious consequences for climate, human health, and the environment.

Multimodal brain deficits shared in early-onset and adult-onset schizophrenia predict positive symptoms regardless of illness stage.

Incidence of schizophrenia (SZ) has two predominant peaks, in adolescent and young adult. Early‐onset schizophrenia provides an opportunity to explore the neuropathology of SZ early in the disorder and without the confound of antipsychotic mediation. However, it remains unexplored what deficits are shared or differ between adolescent early‐onset (EOS) and adult‐onset schizophrenia (AOS) patients. Here, based on 529 participants recruited from three independent cohorts, we explored AOS and EOS common and unique co‐varying patterns by jointly analyzing three MRI features: fractional amplitude of low‐frequency fluctuations (fALFF), gray matter (GM), and functional network connectivity (FNC). Furthermore, a prediction model was built to evaluate whether the common deficits in drug‐naive SZ could be replicated in chronic patients. Results demonstrated that (1) both EOS and AOS patients showed decreased fALFF and GM in default mode network, increased fALFF and GM in the sub‐cortical network, and aberrant FNC primarily related to middle temporal gyrus; (2) the commonly identified regions in drug‐naive SZ correlate with PANSS positive significantly, which can also predict PANSS positive in chronic SZ with longer duration of illness. Collectively, results suggest that multimodal imaging signatures shared by two types of drug‐naive SZ are also associated with positive symptom severity in chronic SZ and may be vital for understanding the progressive schizophrenic brain structural and functional deficits.

Hydrogen annealing induced physical properties of ZnTe thin films

The ZnTe material has an unprecedented role in the fabrication of high efficiency CdTe thin film solar cells and optimization of hydrogen annealing induced physical properties of ZnTe films is next required step. Consequently, in the present work, the impact of Hydrogen annealing temperature on the structural, optical, electrical, topographical, morphological, and compositional properties of ZnTe films is explored. The ZnTe thin films (having 300 nm thickness) are grown via electron-beam evaporation technique on glass and ITO substrates followed by annealing at different temperatures under a Hydrogen atmosphere. The ZnTe films are found to crystallize in cubic phase with (111) predominant peak having crystallite size in the range of 19–28 nm, whereas annealed films demonstrated lower optical transmittance vis-à-vis to pristine films. The PL spectra exhibit two luminescence peaks with a stronger band at ∼351 nm and a weaker band at ∼450 nm. Ohmic behavior of ZnTe films is assured through I–V characteristics, while the AFM images revealed hill-like surface topographies. The FESEM image of pristine films demonstrated a homogeneous surface comprising spherical grains whereas annealed films have spherical, stone, and blisters like morphologies. The EDS patterns assured the Te element richness as well as successful ZnTe films deposition. The observed findings signify that the Hydrogen annealing at different temperatures notably modified the physical properties of ZnTe films. • Hydrogen annealing induced physical properties of ZnTe films are investigated. • The crystallite size is augmented from 19 to 28 nm for hydrogenated ZnTe films. • The straight lines to I–V characteristics ensure formation of Ohmic contacts. • Direct optical energy band gap is found within range of 2.00–2.51 eV for ZnTe films. • Surface topography revealed hill-like structures with varied surface roughness.

Mosquito Larvicidal Activity of DNA Capped Colloidal Silver Nanoparticles

Mosquitoes spread terrible diseases like chikungunya, yellow fever, malaria, dengue, Japan encephalitis and lymphatic filariasis in human beings even causes many deaths in every year. Chemical insecticides cause adverse effect in human beings, also to the environment. In this work, we sought a credible, eco friendly tool to control the vector mosquitoes at their larva stage. It reveals an eco-friendly and effective larvicidal activity of the Deoxyribonucleic acid (DNA) capped colloidal Silver nanoparticles. Characterizations of the Silver nanoparticles were done using absorption spectra and SEM. Spectra shows a predominant peak at 425nm and the SEM image shows the particles size is about 45nm. The third instars of Culex larvae were treated using these colloidal Silver nanoparticles, also the mortality rate for 24 hours was observed with 100% mortality rate at 10 ppm. The LC50, LC90 and confidence interval at 95% were investigated. Colour analysis and the SEM image of the treated larva were performed and confirm that the colloidal Silver nanoparticles were accumulated all over the skin surface of the larva which causes death.

Control of leading-edge separation on bioinspired airfoil with fluttering coverts.

In this work, the aerodynamic role of the artificial covert feathers (i.e., coverts) on an airfoil is experimentally studied in a wind tunnel to investigate the flow control effect on the leading-edge separation. We apply flexible featherlike devices on a high-angle-of-attack airfoil. We use a hot-wire anemometer to measure the velocity profiles and turbulent fluctuations in the downstream wake flow. As a baseline of flow separation, a two-dimensional NACA 0018 airfoil model is set at the angle of attack of 15 ° at the chord-based Reynolds number of 1.0×10^{5}, causing strong leading-edge and trailing-edge shear layers and a low-speed wake flow area in between as large as 0.35 chord length. When deployed on the upper wing surface, the flexible coverts adaptively flutter under the influence of the local unsteady airflow. Hot-wire measurement results show that the leading-edge coverts effectively suppress the flow separation and reduce the size of the wake flow area. The change of power spectral density shows that the predominant peaks as the fundamental and harmonic frequencies are both attenuated due to the suppression of unsteady motions of the shear layers. On the other hand, the fluttering coverts at the trailing edge modify the trailing-edge shear layer by redistributing the turbulent kinetic energy to the high-frequency components. By simultaneous double-point measurement, we find that the leading-edge and trailing-edge shear layers are drawn closer to each other, and the two shear layers show an increased peak in the coherence spectrum. Further multiscale wavelet analysis shows that the perturbations at the 60% chord length increase the large-scale amplitude modulation of small-scale turbulence and therefore they stabilize the leading-edge and trailing-edge shear layers. Meanwhile, the flow intermittency outside of the wake flow area is attenuated as well. The effective flow control effects in the present work are in good agreement with the previous direct observations of bird flight in literature that the coverts on the upper wing surface play an important role in flow separation control during high-angle-of-attack flight. These findings advance the understanding of aerodynamic contribution of the covers on bird wings and reveal the engineering potential of bioinspired coverts for flow separation control of aircrafts and unmanned air vehicles.

Synthesis and characterization of electrical properties of nanostructured zinc oxide film prepared by spray coated seed layer based hydrothermal method

The aim of study was to investigate the carrier transport properties of seed layer assisted nanostructured ZnO thin film. The structural analysis by XRD showed the predominant peak at 34.63° (2θ) corresponding to <002> plane. From the SEM image, it was found that the particles grown vertical nanoparticles on the glass substrate. The optical bandgap of the material was calculated from UV-Visible absorption spectrum which was found as 3.28 eV. The I-V characteristics showed that the film possess semiconducting nature. The electron mobility was determined as 1.60×102cm2/Vs and the resistivity was around 1.99×10−4 Ω.cm and the carrier concentration of the film was 7.54×1020cm−3 by Hall effect measurement. The seed assisted nanostructured film exhibited good electron transport properties which can be applied in many electrical applications like a solar cells, sensors and optoelectronic devices.

Fabrication of Er, Tb doped CuO thin films using nebulizer spray pyrolysis technique for photosensing applications

CuO-based high-performance photo-sensors are a key area of research and challenge in today's scenario. In view of this, we study undoped, CuO:Er (1%),CuO:Tb (1%), and Er(1%),Tb(1%) dual doped CuO thin films for photodetector applications using the nebulizer spray pyrolysis technique. The structural, morphological, and optical features of the coated samples were systematically studied using few techniques such as X-ray diffraction (XRD), Scanning electron microscope (SEM), UV–Vis spectra, Photoluminescence (PL) and two probes. According to the XRD analysis, all the doped thin films show a good crystalline structure with a predominant peak exhibition (002) plane and the doping process enlarged the crystallite size value and obtained a maximum of 44 nm for Er,Tb dual doped CuO film. SEM photo shows the formation of a flaky nanoparticle structure. In the case of light absorption, the absorption level depends on dopant materials such as Er and Tb and the UV absorption level is improved for the dual doped film. The photo-luminescence shows that all the prepared samples exhibit defect-related peaks around 412, 450, 475, 525 nm and the doping process significantly improves the luminescence properties of CuO films. According to Hall effect analysis all prepared samples show the p-type characteristics whose film resistance and mobility are increased and the highest value is noted for Er(1%),Tb(1%) doped CuO thin film. The photo-detection capacity was studied by the analysis of optoelectronic properties for these doped CuO thin films. The UV sensing study indicates, high responsivity (4.85⨯10−1AW−1), external quantum efficiency (113%), and detectivity (1.89⨯1010 Jones) values for the Er, Tb dual doped CuO photodetector. The work also discusses a possible mechanism of ultraviolet photo-detector performance. These findings share a guideline to develop a high-performance photodetector.

Mesoporous Weaved Turbostratic Nanodomains Enable Stable Na+ Ion Storage and Micropore Filling is Revealed to be More Unsafe than Adsorption and Deintercalation.

Advanced wave-shape non-graphitizable carbon sheets are derived, comprising mesoporous weaved turbostratic micropore enabled stable Na+ ion storage. The non-graphitizable amorphous characteristics are determined from the obtained two broad diffraction peaks at 22.7° and 43.8°. The observed D-band at 1325 cm-1 and G-band at 1586 cm-1 confirm the disordered graphitic structure, attributed to the measured specific surface area of 54 m2 g-1. Mesoporous weaved wave-shape carbon sheet architecture is confirmed by surface morphological studies, showing lattice fringes of disordered graphitic structures and dispersed ring patterns for the non-crystalline characteristics. The predominant stable redox peak at 0.014 V/0.185 V and the broader rectangular shape between 0.9 and 0.15 V depict the adsorption-micropore filling mechanism. The mesoporous hard carbon sheet delivers discharge-charge capacities of 450/311 mAh g-1 (1st cycle) and 263/267 mAh g-1 (250th cycle) at 25 mA g-1, exhibiting a superior anode for sodium-ion batteries. Besides, in situ multimode calorimetry results disclose that the micropore filling Na+ ion storage shows a higher released total heat energy of 721 J g-1 than the adsorption (471 J g-1). Ultimately, differential scanning calorimetry analysis of micropore filling Na+ ion storage (discharged state at 0.01 V) has revealed a predominant exothermic peak at 156 °C with the highest released total heat energy of 2183 J g-1 compared to adsorption (553 J g-1) and deintercalation (85 J g-1), indicating that micropore filling status is more unsafe than the adsorption and deintercalation for SIBs.

The application of GO-Fe3O4 nanocomposite for chromium adsorption from tannery industry wastewater

The discharge of untreated tannery industrial wastewater into the environment has resulted in an adverse effect on the ecosystem and public health. Therefore, this work aimed to remove chromium ions from tannery wastewater through magnetite graphene oxide-nanocomposite (GO-Fe3O4). The experimental design of the study was a full factorial 24 approach using pH, adsorbent dose, contact time, and initial chromium concentrations. The results of FTIR analysis revealed the presence of functional groups such as hydroxyl (3438 cm−1), alcohol (1230 cm−1), aromatic (1467 cm−1), ketone (1629 cm−1), and ether (1120 cm−1). Similarly, GO-Fe3O4 acquired a high surface area of 296.2 m2/g whereas the XRD analysis showed the presence of predominant peaks which are attributed to the magnetite component. Moreover, the SEM image showed many ups and downs on the surface of the adsorbent. These cracks of morphology can create a conducive environment for the interaction of adsorbent and adsorbate. The maximum chromium removal of 95.9% was achieved at the optimum conditions of the initial chromium concentration of 40 mg/L, pH 4, adsorbent dose 1 g/100 mL, and contact time of 120 min whereas the removal of chromium from real tannery wastewater was found to be 90.3%. Based on the adsorption isotherm, the Langmuir model was the best fit for experimental data at R2 0.99, indicating homogeneous and monolayer adsorption. Finally, it can be concluded that GO-Fe3O4 was effective for chromium removal, which is a promising technology to be scaled up at the industrial level for wastewater treatment.

Reducing the nanoparticles generated at the wheel\u2013rail contact by applying tap water lubricant at subway train operational velocities

The formation characteristics and the reduction of nanoparticles emitted from wheel–rail contacts at subway-train velocities of 73, 90, and 113 km/h under dry and water-lubricated conditions (using tap water) were studied using a twin-disk rig. The resulting number concentration (NC) of ultrafine and fine particles increased with train velocity under both conditions. Particle generation varied with slip rate under both conditions in both the particle categories. Furthermore, the formation characteristics at 113 km/h under dry conditions showed a notable deviation from those under water-lubricated conditions in three aspects: (i) The maximum NC of ultrafine particles was higher than that of fine particles, (ii) the predominant peak diameter was in the ultrafine particles category, and (iii) the proportion of ultrafine particles was much higher than those of the fine particles. Applying water decreased the NC of ultrafine and fine particles significantly at all tested velocities (by 54–69% and 87–91%, respectively). Adding water increased the NC of particles ≤ 35 nm in diameter, possibly owing to the increase in water vapor and mineral crystals from tap water. Overall, this study provides a reference for researchers aiming to minimize nanoparticle formation at the wheel–rail contacts by applying a lubricant.

Structural and optical characterization of nanostructured undoped CuO and cobalt - doped CuO thin films

The undoped CuO and CuO:Co films are grown using spray pyrolysis technique(SPT). The deposited films undergo a clear morphological change due to an increase in Cobalt dopant from 0 to 4 %. The predominant peak was (200) plane has been confirmed by Xray diffraction. Maximum crystalline size was at the (CuO: 4% Co) film, and the strain decreases from 2.98 to 2.59. Study of the morphology specifies the presence of homogeneous grains, these grains were not homogeneous and had different sizes by adding Co atom. AFM images a reduction in roughness from (7.06 to 3.64) nm. The crystallite size was in the area of 41.35 nm to 32.46 nm as calculated by Scherrer’s formula. The average transmittance values for the films were (77, 74 and 71) % for Undoped CuO, CuO: 2% Co and CuO: 4% Co respectively. The optical energy gaps of the films were calculated. the absorption coefficient increased with an increase at 2% or 4% Cobalt dopant, the band gap of Undoped CuO sample was 2.12 eV, and then decreased slightly with Cobalt content to become 2.04 eV for CuO: 2% Co and 2.04 eV for CuO: 4% Co. also The refractive index and extinction coefficient increased via Cobalt contents.