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This study explores the coupling effect of pond ash (PA) and polypropylene (PP) fiber to control the strength and durability of expansive soil. The PA is used to chemically treat the expansive soil and PP fiber is adopted as reinforcement against tensile cracking. The sustainable use of PA and PP fiber are demonstrated by performing mechanical (i.e. unconfined compressive strength, split tensile strength and ultrasonic pulse velocity), chemical (pH value, electrical conductivity and calcite content), and microstructural analyses before and after 2nd, 4th, 6th, 8th and 10th freezing-thawing (F-T) cycles. Three curing methods with 7 d, 14 d and 28 d curing periods are considered to reinforce the 5%, 10%, 15% and 20% PA-stabilized expansive soil with 0.25%, 0.5% and 1% PP fiber. In order to develop predictive models for mechanical and durability parameters, the experimental data are processed utilizing artificial neural network (ANN), in association with the leave-one-out cross-validation (LOOCV) as a resampling method and three different activation functions. The mechanical and durability properties of the PA-stabilized expansive soil subgrades are increased with PP fiber reinforcement. The results of ANN modeling predict the mechanical properties perfectly, and the correlation coefficient (R) approaches up to 0.96.

Metal additive manufacturing processes offer unique opportunities for the biomedical industry owing to their ability to produce custom-designed implants with near-net shape and intricate geometry. Co–Cr alloys are among the most popular metallic biomaterials due to their excellent resistance to both corrosion and wear. Several studies have been reported in recent years on studying the processing-structure–property relationships in additively manufactured Co–Cr alloys. However, there is a significant gap in knowledge of critical issues such as the microstructural features and properties of additively manufactured parts as well as the role of the processing parameters and post-manufacturing treatments. The performance of the additively manufactured Co–Cr alloys for biomedical applications such as fatigue, wear, corrosion, and the biological response is poorly characterized as yet. This article presents an overview of the existing literature available on additively manufactured Co–Cr alloys and identifies challenges and opportunities for their use in biomedical implants.

The alloy Ti6Al7Nb with the in situ reinforcement of TiB has been processed by selective laser melting (SLM). Premixed Ti6Al7Nb-xTiB2 powders were used for the powder bed. The microstructure of the Ti6Al7Nb alloy was characterized by martensite (αʹ), while the addition of TiB2 led to a bimodal microstructure with refined features as a result of in situ formation of fine TiB phase. A prismatic ││BD fiber texture was evident in all samples, though the texture formation was found to be affected by the change in the phase transformation pathway due to the formation of TiB. Higher hardness and yield strength (YS) in the composites as compared to the base material are attained. The examination of corrosion response revealed a lower corrosion current (Icorr) value for all the specimens in simulated body fluid (SBF) in comparison to Ti6Al4V alloy. The improved mechanical behavior and better corrosion resistance indicate the potential of SLM-processed Ti6Al7Nb/TiB composite as a suitable replacement for Ti6Al4V alloys for bio-implants.

The role of shear strain and deformation temperature on the microstructure and texture evolution in commercially pure (CP) titanium was investigated in the present study. CP titanium samples were s...

This study investigates heterogeneity in the deformation of an annealed sheet of commercially pure titanium (cp-Ti), its variation with loading direction and its influence on dwell fatigue response...

A robust real-time damage detection technique of earthquake-excited structures based on a new demodulation technique for nonlinear and non-stationary vibration signals through the identification of signal envelopes in real time is presented. In the present work, the need for the detection of envelope in a vibration signal in real time is addressed by reformulating the concept of Hermitian interpolation functions to a recursive Hermitian polynomial, which is a key entitlement of the present work. Once, the near real-time demodulation is achieved, the proposed framework proceeds to the newly developed error-adapted framework by addressing the errors accrued between the standard and generalized eigen perturbation formulation in the context of real-time estimation of proper orthogonal modes and linear normal modes. In the adaptive framework, the error is modeled as a feedback, which is constructed to account for the truncation in the order of eigen perturbation. In addition to the improved accuracy due to the envelope extraction, the proposed error-adapted eigen perturbation further improves the detectability over the currently available eigen perturbation–based real-time algorithms. To ensure robustness of the proposed algorithm, a new real-time damage indicator based on the maximum of principal eigenvector of the evolving transformed covariance matrix is proposed. The proposed modules together not only improve the detectability of the damage detection in real-time but also enhance the overall performance in presence of non-stationary excitation, that often mask the damage information in the higher energy zones of the amplitude and frequency-modulated response. Simulations for the proposed framework is performed by considering a 5 degrees-of-freedom linear and base-isolated nonlinear structural system driven by non-stationary stochastic excitations with damage simulated at intermediate floor at a particular time instant. Evidence of the near real-time demodulation and/or envelope removal from the signal and improved damage identification is also provided. An examination of the proposed framework using experimental data further validates the robustness of the proposed scheme.

Thermo-mechanical softening forms the basis for hot working of metallic materials. In materials with hierarchical microstructures such as martensite, softening processes can be mediated or restricted by interfaces. In the present study, the operation of three distinct softening mechanisms in P91 martensitic steel during thermo-mechanical processing (TMP) has been investigated. The softening in the present case is found to arise from the interplay between microstructural strain, texture, and phase transformation. Further, softening characteristics vary with the TMP parameters. The manifestation of softening has been explored at the macroscopic, mesoscopic, and microscopic length scales. It has been found that each softening mechanism is differently mediated by the interfaces and is governed by local crystallographic orientation. Thermo-mechanical softening of martensite proceeds through orientation-dependent dynamic recrystallization. The role of specific interfaces in impeding this mechanism has been highlighted. In contrast, TMP of austenite proceeds through interface-mediated softening, combining the phenomena of recrystallization and phase transformation.

A deterministic reaction-diffusion–drift model is used for the time kinetics of bulk gate insulator trap generation in p-channel Field Effect Transistors (FETs) under inversion stress. The consistency of the deterministic and stochastic versions of the model is shown. The model is independently validated using stress-induced leakage current data from various reports. The model is incorporated into the already existing bias temperature instability (BTI) analysis tool framework and validated using negative BTI data. The measured data from FinFETs having different channel material, substrate type, gate insulator process, and fin length, as well as gate-all-around stacked nano sheet (GAA-SNS) FETs are modeled.

Microbially induced calcite precipitation (MICP), a sustainable approach for sand biocementation, was investigated in previous studies based on metabolic activity of individual microorganisms. The individual bacteria, specifically Sporosarcina pasteurii (SP), Bacillus subtilis (BS), and Lysinibacillus sphaericus (LS), were found capable enough for sand biocementation. However, present study investigates synergistic effects of using bacterial-hybrids on cementation and consequent improvement in sand properties. The SP, BS, and LS strains were used in different combinations to create bacterial-hybrids and applied under simulated non-sterile field conditions. Initially, sand biotreatment was carried out in plastic tubes up to 14 days, using bacterial mixtures and 0.5 M cementation solution. Biocemented specimens were tested for calcite precipitation, XRD, FTIR, and SEM. The SP and LS combination (SPLS hybrid) showed maximum calcite precipitation, which is further used for biotreatment to create cylindrical sand samples for testing improved engineering properties. These samples were prepared using 0.5 M cementation solution in three pore volumes (1, 0.75, and 0.5 PV) and treatment cycles (12, 24, and 48 hrs TC) up to 18 days. Biocemented samples were tested for permeability (6th, 12th, and 18th days of biotreatment), unconfined compressive strength (UCS), split tensile strength (STS), ultrasonic pulse velocity (UPV), and consolidated undrained stress-strain response. Durability of biocementation was also investigated by determining reduction in strength and UPV subjected to freeze-thaw (FT) cycles (5, 10, 15, and 20). The results showed maximum UCS of 1902 kPa, STS of 356 kPa, UPV of 2408 m/s, and coefficient of permeability reduction up to 91%. The higher results were achieved with 11.11% calcite content in 1PV-12TC treated samples. The 1PV-12TC treated samples resulted in 4.2%, 8.3%, 17%, and 35% reduction of strength after 5, 10, 15, and 20 FT cycles, respectively. Overall, biocementation using hybrid bacteria is shown significant to improve sand's engineering properties, including potential to mitigate liquefaction.

The potassium dihydrogen phosphate (KDP) is a popular nonlinear optical material. Optically good quality LiCl doped KDP crystals have been grown by slow solvent evaporation method at room temperatu...

Microstructure evolution and texture development during cold rolling of a Ti15333 alloy were systematically investigated in the present work. Texture was simulated using mean-field [Visco-Plastic Self-Consistent (VPSC) and Taylor] models. Evolution of crystallographic texture was also simulated using the Visco-Plastic Fast Fourier Transform (VPFFT) model. The as-received samples (in the hot-forged and hot-rolled condition) were cold rolled unidirectionally up to 20, 40, 60 and 80 pct thickness reductions. Increase in the cold-rolling reduction resulted in changes in the crystallographic texture as well as grain morphology. The initial hot-rolled sample consisted of in-grain shear bands that were aligned approximately ± 35 to 40 ° with respect to the sample rolling direction. Shear band density gradually increased with the increase in cold-rolling reduction, and these bands usually represent narrow zones of intense strain. α (RD//〈110〉) and γ (ND//〈111〉) fibers were observed in all the cold-rolled samples. The volume fraction of both these fibers was found to be highest for the 80 pct deformed sample. For mean-field simulations, the normalized difference of the texture index (normalized TIdiff) was found to be a good criterion to represent the match between the simulated and experimental texture. The affine model (VPSC) was found to give a good match with the experimental texture compared to the Taylor models. The γ-fiber and α-fiber were always overestimated in mean-field VPSC simulations. Extensive shear band formation could be the possible reason for mismatch between the simulated and experimental texture. For VPFFT simulations, the general texture evolution involved the intensification of the γ-fiber and α-fiber texture. Simulated texture was reasonably well predicted quantitatively with VPFFT, analyzed based on the volume fraction of the different texture fibers/components.

Hot deformation and softening response for the titanium aluminide Ti–48Al–2V–0.2B has been investigated. The deformation response to softening mechanisms has been examined. Deformation experiments were carried out in the strain rate range 0.01–10 s−1 keeping the temperature constant at 1200 °C and in the temperature range 1000–1200 °C at the strain rate 1 s−1. With an increase in strain rate, the microstructural changes associated with the softening mechanism include breaking of the lamellae, spheroidization of the broken laths and dynamic recrystallization. For the strain rate 1 s−1, deformation in the (α2 +γ) phase field leads to fine recrystallized grains, remnant lamellae and cavitation along the grain boundaries (for temperatures 1000 and 1100 °C). Deformation in the (α +γ) phase field leads to dynamic recrystallization at the shear bands, within the lamellae, breaking and rotation of the α phase during the continuous increase in the deformation strain.

The prediction of precipitated graphite nodules size and distribution in a large industrial casting is critical to understand the mechanical behavior of cast iron components used in heavy vehicles. An accurate prediction of the graphite nodules requires a validated and integrated macro-micro modeling framework, which forms the motivation behind the present study. Classical theories in the literature (Lesoult et al. in Acta Mater 46:983–995, 1998) proposed two stages of graphite growth: in (i) liquid stage, after encapsulation by the austenite grain, and in (ii) solid stage, surrounded by only austenite phase. In this work, a new stage of graphite growth was proposed, where a graphite nodule was in direct contact with the liquid metal, existing in the presence of an austenite grain separated from the nodule. The resulting three-stage graphite growth in a microscopic control volume was formulated using a volume-averaged micro-model. This was made to evolve with the help of a macroscopic temperature field obtained from finite-element-based numerical simulation and thus creating a comprehensive modeling framework. Further, for the first time, a diffusion-based deforming-grid micro-model was developed to obtain the exact nature of a single graphite nodule growth based on the position of individual phases in the microscopic control volume. The model predictions were validated with experimental results from the step-casting experiments in the present study, as well as with the observations of single nodule growth from in situ synchrotron X-ray tomography (Bjerre et al. in Model Simul Mater Sci Eng 26:085012, 2018; Azeem et al. in Acta Mater 155:393–401, 2018). The proposed models captured, faithfully, the experimental patterns of graphite growth evolution, number density of the nodules, and the size distribution as a function of cooling rate. This integrated multi-scale modeling approach is envisaged to be effective for determining exact graphite growth behavior of a single nodule and volume-averaged graphite growth in a large casting.

Static and dynamic fracture experiments are performed using fatigue pre-cracked three-point bend specimens of a rolled AZ31 Mg alloy on a servo-hydraulic universal testing machine and a Hopkinson bar setup, respectively. The results are interpreted using in-situ optical imaging along with digital image correlation analysis. Microstructural analysis reveals that the fracture mechanism changes from twin-induced quasi-brittle cracking for static loading to micro-void growth and coalescence under dynamic loading accompanied by decrease in tensile twinning near the tip with loading rate. By contrast, the density of twins near the far-edge of the ligament and associated texture change enhance strongly with loading rate. The fracture toughness increases dramatically at high loading rates which is attributed to enhanced work of separation and dissipation in the background plastic zone.

In this research work, a mathematical model was formulated to establish a relationship between thermal conductivity and other physical parameters with the aim of improving thermal conductivity and thermal stability for heat sink applications. The proposed model was validated considering three composite materials namely aluminium graphene, aluminium graphite and copper graphite. This proposed model provides some dominating parameters that affect the thermal efficiency of the composite. The results obtained with this model are in close agreement with the experimental data. The variables considered in the model were converted to dimensionless number by employing Buckingham pi theorem which gave rise to dimensionless efficiency parameter (Y) and process parameter (X). Thus, model establishes unique exponent for each material in identifying distinct features and physical significance in selection of heat sink material.

The present study investigates the structural, electronic and thermoelectric properties of Uranium Monocarbide using Density Functional Theory based on first principles calculation. The electronic structure of UC was calculated using the Quantum Espresso code and the Thermoelectric properties were evaluated using the BoltzTrap code based on the semiclassical Boltzmann transport theory. The dependence of strain on the thermoelectric properties such as electrical and thermal conductivity, Seebeck coefficient and thermoelectric figure of merit (ZT) is calculated. At room temperature, the Thermoelectric figure of merit (ZT) decreases under compressive strain whereas it increases over tensile strain.

The electronic and optical properties of rare-earth based half-Heusler ErPdSb compound are investigated by the using of first-principle density functional theory. The generalized gradient approximation (GGA) with spin–orbit coupling (SOC) and Hubbard parameter (U) have been used for exchange and correlation effect. Our calculations of electronic band structure show the half metallic nature of ErPdSb compound. The majority spin (up) states found semiconductor nature with a narrow indirect band gap 0.25 eV. While minority spin (down) states found metallic with no gap. The optical properties are investigated via optical conductivity, reflectivity along with other related optical constants such as absorption coefficient and refractive index.

The unique structural features and advantageous pore distributions of alumina hollow fibers can be exploited to tune the selectivity in heterogeneous catalysis. Formation of a finger-like cavity structure is the unique characteristic of the phase inversion method, which provides a larger surface area to volume ratio desirable for catalytic reactions. This feature, along with a highly porous sandwiched skin layer, makes this architecture superior to conventional powder catalysts or other structured catalyst forms like monoliths. Alumina hollow fibers are prepared by the modified phase inversion method and characterized for their pore size and distribution. Ni metal nanoparticles are uniformly deposited in the Al2O3 hollow fibers to prepare a Ni/Al2O3 catalyst and tested for the CO2 methanation reaction. Suitable reactor and catalyst loading methods are designed and optimized to achieve higher CO2 to methane conversion in a temperature range of 225 to 400 °C. The α-alumina phase, which is usually reported to be a poor support for Ni in CO2 methanation in the conventional fixed bed configuration, showed high activity when modulated as hollow fibers. Also, the selectivity to CH4 is enhanced and minimal CO formation is observed. The kinetic rate expressions are simulated for the prediction of methane and CO gas evolution at the outlet with temperature. The experimental results for the gas composition are in good agreement with the model predictions. The advantage of such a module reactor is explained based on the mass transfer limitations and consequently the reaction time constants arrived at from the predicted gas compositions.

In this paper, we developed highly accurate ensemble machine learning models integrating Reduced Error Pruning Tree (REPT) as a base classifier with the Bagging (B), Decorate (D), and Random Subspa...

We have studied the effect of iron-iron oxide particles on the trans-cis isomerization of azobenzene moieties in the novel polyethylene glycol itaconate-azobenzene based side chain liquid crystalline polymer (PEGIA). Langmuir monolayers of the PEGIA molecules are spread at air-water interface, with water subphase containing different concentrations of iron-iron oxide particles. The kinetics of the isomerization of azobenzene moieties in the polymer was studied by surface manometry technique. We find that the presence of iron-iron oxide particles in the subphase affects the rate constant of trans-cis photoisomerization and it decreases exponentially as a function of concentration of particles in the subphase. The critical concentration of iron-iron oxide particles above which the rate constant of photoisomerization negligibly changed was found to be about 2.468 μg cm− 3.

In the present investigation, the evolution of texture and microstructure during incremental sheet forming was investigated. Hot-rolled sheets of commercially pure titanium were subjected to single-point incremental forming to obtain truncated pyramid geometries. It was observed from texture measurements that there was splitting of basal poles along the transverse direction. Moreover, a significant number of twins was observed in the deformed microstructure with the fraction of extension twins being highest compared to other variants. The crossing of deformation twins, formation of twin lamellar structure and formation of secondary extension twins within primary contraction twins were additionally observed. The state of deformation in the pyramid walls was analyzed via finite element method which in turn was used as input for carrying out crystallographic texture simulations via visco-plastic self-consistent simulations. It was observed that the state of deformation in the wall regions is plain strain compression plus through-thickness shear.

A stochastic reaction–diffusion drift model is used to simulate the time kinetics of interface and bulk oxide traps responsible for bias temperature instability (BTI), stress-induced leakage current (SILC), and time-dependent dielectric breakdown (TDDB) in MOSFETs. Trap generation and passivation are calculated using dissociation and repassivation of trap precursors and simultaneous diffusion and/or drift of atomic, molecular, and/or ionic species. The average of multiple stochastic simulations is used to qualitatively explain the measured BTI and SILC data. The difference in BTI and SILC time kinetics, variation in SILC time kinetics across reports, and oxide thickness dependence of TDDB Weibull slope variation are also qualitatively explained.

The thermoelectric efficiency of skutterudite materials can be improved by lowering the lattice thermal conductivity via the uniform dispersion of a nanosized second phase in the matrix of filled C...

Optimum maturity and ripeness at the time of harvest is highly important to maintain the nutritional parameters of fruits. Maturity and ripeness of most of the fruit samples depends on various physiochemical parameters such as color, shape, size, total soluble solid and many more. Several state-of-the-art solutions such as GC–MS, Electronic Nose, Spectrometer and many more are available to measure various fruit quality parameters but most of the solutions available in the market are bulky, time consuming, lab-level and requires skilled manpower for operation. Presented manuscript reports a battery operated, smartphone spectrometer based solution to carry out the variety of activities in the field. Overall device uses UV–Vis-NIR led array as source and collection of spectral sensors (AS7262 and OPT101) to acquire overall UV–Vis-NIR spectrum over the range of 400–1000 nm with the resolution of 40 nm. Designed source and detector modules have been interfaced with designed triggering, filter and amplification circuit. A low power wireless solution along with on-board microcontroller facility has been designed and interfaced with circuits, source and detectors. All essential components such as source, detectors, filters, lens and all circuits have been assembled in a housing of dimensions 18.0 × 9.0 × 6.0 (in cm) and the entire device weighs 183.35 g. Different statistical and neural network based modelling techniques have been explored to design prediction models for total soluble solids, weight, volume, chlorophyll, sugar content and acidity. Models have been evaluated based on accuracy, memory and time usage. Best performed models have been used to train handheld smartphone based spectrometer device to predict various quality parameters for citrus samples. System communicates data to smartphone based android app to display various parameters. Android app also provides facility to save data on cloud with tree and orchard ID to monitor overall yield and harvesting time.

The current study analyzes the tree diversity and regeneration status of species between repeated forest fires and unburned areas of the tropical dry deciduous forest of Panna Tiger Reserve (PTR), ...

The Ni modified samples ZnFe2-xNixO4 with x = 0, 0.05, and 0.10 were synthesized using the sol-gel combustion method at 60 °C. The phase of obtained samples was determined using X-ray powder diffraction and found that it crystallized into a cubic spinel group. The lattice parameter of samples was decreased with increasing Ni concentration. However, the local symmetry of samples was explored using Raman spectroscopy. The presence of Raman band at 655 cm−1 was assigned to the vibration of Fe-O; found to be shifted towards higher wavenumber reconfirm the incorporation of Ni. The optical bandgap of the samples was determined using the Tauc plot and found to be in the range of 2.50 to 2.95 eV, which reflects the inorganic semiconducting nature of samples. Dielectric properties of samples were studied as a function of frequency and temperature show the presence of interfacial and orientational polarization in the sample. The resistivity of samples has been studied using Arrhenius model, and found three different regions of conduction within investigated temperature range. The first region assigned to the hopping of electron, while the second region to the hopping of polaron via the orientation of dipole ( 2 Ni Fe ' - 2 h . ) , or ( 2 Ni Fe ' - V o . . ) , and the third region assigned to migration of V o . . or e ' / h . . The conductivity of samples found in range of (0.85–8.95) S-cm−1 higher than conventional electrolytes used in IT-SOFCs. Based on these studies, the present materials can be used as a potential candidate for semiconductor devices and electrolytes in IT-SOFCs applications.

CuFe2O4/β–SiC and CuFe2O4/SiO2 catalysts were prepared by wet impregnation method, following the high temperature solid state route and their catalytic performance is evaluated in the SO3 decomposition reaction of the Sulfur–Iodine (S–I) cycle for hydrogen production. The synthesized catalysts are characterized by XRD, FT–IR, TGA, XPS, N2–BET, TEM, HR–TEM, FESEM–EDS and elemental mapping. CuFe2O4/β–SiC catalyst shows higher activity and stability while sintering is observed in the spent CuFe2O4/SiO2 whose activity decreased during the reaction time on stream. Kinetic studies were performed over CuFe2O4/β-SiC in the temperature range of 800–900 °C using wide range of space time, 6.54–44.40 kg h kmol−1. A heterogeneous kinetic model was developed based on the product distribution and the reaction rates determined by the model fitted well with the experimental rates at different temperatures.

Mixed-mode (I/II) fracture experiments on rolled AZ31 Mg alloy are conducted using notched four point bend specimens along with in-situ imaging. Digital Image Correlation (DIC) technique is used to analyze the images and map out the deformation and strain fields. With increase in mode II component of loading, a monotonic reduction in the notched fracture toughness (Jc) is observed. Fractographs reveal that the fracture mechanism transitions first from (ductile) micro-void growth and coalescence to twin induced quasi-brittle failure and then to shear cracking as the loading changes from mode I to II. Detailed optical micrographs and EBSD maps show profuse tensile twinning in the ligament, especially near the far-edge of the specimen leading to pronounced texture changes. However, the micro void size near the notch tip as well as the twin density in the ligament reduce with higher mode II component. The pronounced drop in fracture toughness and the changes in the associated mechanism with increase in mode-mixity are rationalized from the combined effects of hydrostatic stress, plastic strain localization and tensile twinning.

In the present study, the Fe-Al-based compositions developed as low-density steel are subjected to addition of Cr and Mn to increase the elastic modulus. In this regard, Fe-3.7Al-3.1Mn and Fe-6.5Al-6.3Cr steels are produced via melting and casting. The steels are cold-rolled to 98% thickness reduction followed by subsequent annealing at 750 °C. A detailed characterization based on x-ray diffraction and electron back-scattering diffraction shows the stabilization of ferrite phase upon the addition of Cr and Mn with a further reduction in density. The expansion of the lattice is observed after ternary alloying additions. The increase in the yield stress and ultimate tensile strength is noticed upon ternary alloying additions. The Cr and Mn addition also led to an increase in the elastic modulus compared to binary Fe-Al low-density steels.

This manuscript introduces a handheld machine vision based system design that is capable of standalone operation using touch screen based user interface and also can operate through smartphone based android app. System uses 8.0 Megapixel, 1080p CMOS camera interfaced with quad-core ARM Cortex-A53 processor based computing platform (Raspberry Pi computing platform) for real time image acquisition and processing. Multi-spectral led array has been used to compensate the effect of external illumination and also to increase the accuracy of measurement. System stores acquired images on interfaced 16.0 G.B. external memory card with date and time information. Various segmentation methods have been explored to extract region of interest in acquired images and compared based on the capability of segmentation in real-time. Segmented images have been used to extract different features such as color, shape, size and texture using various image processing algorithms. Extracted features have been fused together and undergone through different statistical and neural network based modelling methods to correlate features dataset generated using handheld system with standard quality parameters of collected citrus samples. Performance of the established correlation models for various quality parameters such as chlorophyll, sugar content, TSS, weight, pH and volume have been evaluated and best performed models for each quality parameter has been used to train the developed handheld machine vision based system. Overall system is battery operated and also enables cloud connectivity using on-board Wi-Fi facility or smartphone based android app. Overall device has dimensions of 12.0 × 6.0 × 4.0 (in cm), weighs 139.07 g and runs with 5-V rechargeable battery.

Ti-Nb-based low modulus metastable β-titanium alloys are popular choice for orthopedic implant materials. The performance of these materials could be affected by variation in crystallographic texture developed during processing. In the present study, texture evolution during unidirectional rolling and multi-step cross-rolling of the alloys Ti-34Nb-2Ta-3Zr-0.5O (TNTZO) and Ti-34Nb-2Ta-0.5O (TNTO) (in wt pct) has been studied. In both the alloys, the rolling texture is characterized by the absence of RD∥〈110〉 fiber, and cross-rolling leads to a stronger texture than unidirectional rolling. However, the prominent texture components in the cross-rolled condition are different for the two alloys. The TNTZO alloy shows the formation of a strong γ-fiber (ND∥〈111〉) along with {001}〈110〉 components while in TNTO, the texture is dominated by strong {001}〈110〉 component. These experimental results have been analyzed by simulations using viscoplastic self-consistent model and further validated by microstructural analysis using electron back scattered diffraction (EBSD). The deformation texture evolution has been attributed to a predominantly $$ \left\{ {11\overline{2} } \right\}\left\langle {111} \right\rangle $$ slip. The simulated texture of Ti-34Nb-2Ta-0.5O alloy shows a minor deviation from the experimental texture, which can be related to the reduced stability of this alloy due to the absence of Zr.

We study the effect of molecular conformation on the electronic coupling between the donor amines and acceptor 1,8-naphthalimide (NPI) in a series of D-A systems 1-4 (A = NPI; D = phenothiazine, phenoxazine, carbazole, diphenylamine, respectively, for 1, 2, 3, and 4). Weakly coupled systems show dual emission in the solution state, while strongly coupled systems show single emission bands. The energy of transitions and photoluminescence (PL) quantum yield are sensitive to the molecular conformation and donor strength. These compounds show delayed emission in the solutions and aggregated state and phosphorescence in the solid state. Compounds 3 and 4 with weak donors exhibit intermolecular slipped π···π interactions in the solid state and consequently exhibit dual (intra- and inter-) phosphorescence at low temperature. Steady state and time-resolved PL studies at variable temperature together with computational and crystal structure analysis were used to rationalize the optical properties of these compounds. The delayed emission of these compounds is sensitive to molecular oxygen; accordingly, these molecules are utilized for differential imaging of normoxia and hypoxia cancer cells.

The evolution of deformation texture and microstructure in commercially pure Al (cp-Al) and two Al–Mg alloys (Al–4Mg and Al–6Mg) during cold rolling to a very large strain (true strain et ≈ 3.9) w...

In this study, mechanical properties and microstructural investigation of Ti64 at high strain rate are studied using a split-Hopkinson pressure bar method under compression for temperatures up to 800 °C. Flow softening in the mechanical response of material to such loading conditions hints at instability in compression, which increases with an increase in temperature. Microstructural characterization of the deformed material is characterized using the electron-backscattered diffraction technique. It reveals the presence of instabilities in Ti64 in the form of a fine network of shear bands. The shear band width grows with an increase in temperature along with the area fraction of shear band in the material, displaying its improved capacity to contain microstructural instabilities at higher temperature. After a detailed microstructural investigation, a mechanism for shear band widening is proposed. Based on this mechanism, a path generating nuclei within shear bands is discussed.

Mushroom is considered as a functional food rich in both nutrients and medicinal properties. Over the years due to increased recognition of its medicinal and nutritional values and income generating potential the demand for mushrooms has been on the rise. However, mushroom have shorter shelf-life because of their high respiration rate and lack barriers to prevent water loss and microbial attack. Various physico-chemical changes takes place in mushroom during postharvest period like moisture loss, discoloration, texture loss, nutrient loss, microbial spoilage, etc. In order to improve self-life and preserve quality of mushroom, various preservation methods are used which involve thermal, physical and chemical processes. This article highlights recent methods and techniques of preservation of postharvest mushrooms.

The Indian Himalayan region has been severely affected by landslides causing an immense loss in terms of human lives and economic loss. The landslides are usually induced by rainfall which can be slow and continuous or heavy downpour. The incidences of landslide events in Indian Himalayas have been further aggravated due to the rapid increase in urbanization and thus its increasing impact on socio-economic aspects. There is a dire need for understanding landslide phenomena, estimating its occurrence potential and formulating strategies to minimize the damage caused by them. One of the most affected area is Kalimpong of Darjeeling Himalayas where significant studies have been conducted on zonation, threshold estimation and other related aspects. However, a comprehensive study in terms of temporal prediction for this region remains unattended. The paper deals with assessing landslide hazard using a rainfall threshold model involving daily and cumulative antecedent rainfall values for landslide events. The threshold values were determined using daily rainfall and antecedent rainfall using precipitation and landslide records for 2010–2016. The results show that 20-day antecedent rainfall provides the best fit for landslide occurrences in the region. The rainfall thresholds were further validated using rainfall and landslide data of 2017, which was not considered for threshold estimation. Finally, the results were used to determine the temporal probability for landslide incidence using a Poisson probability model. The validated results suggest that the model has the potential to be used as a preliminary early warning system.

The major bottleneck of first principle based beyond Born–Oppenheimer (BBO) treatment originates from large number and complicated expressions of adiabatic to diabatic transformation (ADT) equation...

Variation in tree biomass and carbon (C) stocks in tropical dry forests is important at both regional and global scale to know their contribution in global C cycle. In Indian tropical forests, the ...

Filling the voids of cage forming compounds with loosely bound electropositive elements and by incorporating nano-sized secondary phases are promising approaches to enhance the thermoelectric figure of merit of these materials. Hence, in this work, by combining these two approaches-inserting In into the voids of skutterudite Co4Sb12 as well as dispersing nanoparticles (GaSb)-we have synthesized various samples via ball-milling and spark plasma sintering. InSb as the secondary phase of the matrix, mixed with GaSb, forms the solid solution Ga1-xInxSb. Nanocrystalline grains together with a few larger grains (10-30 μm) are found to be spread in In0.2Co4Sb12. The former is comprised of either InSb, GaSb or Ga1-xInxSb. Because of their identical space group and similar lattice parameters, InSb, GaSb and Ga1-xInxSb could not be detected separately in EBSD. High resolution transmission electron microscopy (HRTEM) was used to resolve different phases, which showed GaSb grains of size ∼10-30 nm and InSb grains of size ∼30-100 nm. Scattering of charge carriers at the interfaces of InSb, GaSb and Ga1-xInxSb as well as the matrix phases increased both the electrical resistivity and Seebeck coefficient. The multi-scale size distribution of grains, of both the matrix phase and the secondary phases, scattered phonons within a broad wavelength range, resulting in very low lattice thermal conductivities. As a result, an enhanced figure of merit of 1.4 was achieved for the (GaSb)0.1 + In0.2Co4Sb12 nanocomposite at 773 K.

The microstructure and texture evolution of an equiatomic CrCoNi medium-entropy alloy during cold-rolling has been investigated. For this purpose, the alloy has been rolled up to a true strain of about 2.3. The microstructure evolution during rolling reveals that mechanical twinning contributes to deformation. With increasing rolling reduction the alloy shows a gradual development of a α-fiber type texture. The experimental texture evolution is compared with the visco-plastic self-consistent (VPSC) model simulations taking into account twinning. The simulated textures show a continuous development of a α-fiber in agreement with experiment.

In this paper a 2.4-GHz non-return to zero (abbreviated as NRZ) active downconversion mixer for transceiver system is demonstrated. It features with the double- balanced topology, NRZ mechanism, an effecting biasing technique and a current mirror technique are used to achieve the requirements. Downconversion mixer is realized on 180 nm CMOS technology. Despite of trade-off between conversion gain and linearity we can achieve very high conversion gain with moderate linearity. Simulations using cadence tool exhibits a conversion gain of 24.61 dB, a third order intercept point of 6.17 dB, a 1-dB compression point of − 5.86 dB and a second order intercept point of + 87.66 dB at 1.8 V supply.

The objective of this study was to evaluate the utility of gelatin-norbornene (GelNB), which is cross-linkable via thiol-ene click chemistry, and the photoinitiator lithium phenyl-2,4,6 trimethylbenzoylphosphinate (LAP) for 3D bioprinting. These materials were compared to two widely used materials, gelatin-methacryloyl (GelMA) and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (I2959). Characterization of photocuring kinetics revealed that LAP markedly improved the kinetics compared to I2959, which improved stability and print fidelity. Additionally, GelNB exhibited improved photocuring kinetics, improved stability, and decreased filament spreading compared to GelMA. However, inks containing GelMA yielded at lower stress, were more easily extruded, and produced smoother filaments. NIH 3T3 fibroblasts exhibited high viability in printed constructs, regardless of the gelatin derivative or photoinitiator used. Overall, these results support the selection of LAP over I2959 and suggest that GelNB could be a useful alternative to GelMA, although further work is needed to optimize GelNB extrusion.

The (K0.90Li0.10) (Nb0.80Ta0.20)0.99Mn0.01O3 (KLTN) ceramic has been synthesized by the conventional solid-state reaction route. The Rietveld refinement X-Ray diffraction (XRD) patterns confirmed the single-phase orthorhombic crystal structure with space group Amm2. The frequency dependent electrical properties were examined by the complex dielectric and impedance spectroscopy in the temperature range 30 °C–500 °C where multiple structural phase transition was observed with high dielectric constant, low tangent loss and well saturated electric polarization. The shifting of the ferroelectric phase transition temperature by 30 °C in heating and cooling mode suggests the irreversible motion of the domains and domain walls and significant effects on grain boundaries on structural phase transition temperature. A series of phase transitions from orthorhombic to tetragonal (∼190 °C) and tetragonal to Cubic (∼390 °C in cooling and 420 °C in heating) have been obtained in the wide range of temperature. The different type of analogy such as Modulus formalism, complex impedance spectra, frequency dependent conductivity, the activation energy of charge carriers has been used to understand the microstructure-electrical properties relation.

An accurate characterization of the seasonal and inter-annual variability of agricultural residue burning in tropics is needed to devise strategies to control or minimize substantial amounts of particulate matter and pollutants released to the atmosphere through the burning of agricultural residues. The present study quantifies the spatiotemporal changes in agricultural residue burning in Madhya Pradesh, India. In this study, the Moderate Resolution Imaging Spectroradiometer (MODIS) data on the occurrence of fire over a period of 15 years (2002–2016) was used to characterize the spatial and temporal patterns of agricultural residue burning in Central India. Overall, there was an increasing trend of fire occurrence, which increased from 1268 in 2002 to 7915 in 2016. Most of these fires were in croplands (48.1%) followed by deciduous broadleaf forests (36%). Cropland fires were increased almost 10-fold from 454 in 2002 to 4359 in 2016 at an average annual rate of 64%. The agricultural residue fires were high in Rabi harvesting period (March to May), as compared to that in Kharif harvesting period (October to December). The present study indicates an increased agricultural residue burning activity in the Madhya Pradesh and needs an immediate attention and develop sustainable alternative methods for crop residue management. The present study also suggests that Modis can be used for long-term assessment of small fires. We recommend ploughing of agricultural residues into the soil as a sustainable and eco-friendly alternative to the burning of crop residues.

In glancing angle electron beam evaporation technique, the deposition geometry has been engineered in a novel manner in this work to produce extensive tunablity of Ag morphology. A physical plate (collimator) parallel to the substrate has been suitably placed in order to constrain the angle of incoming deposition vapor flux. The distance between substrate and this collimator as well as the distance between substrate to crucible orifice has been optimized for maximum variation in Ag morphology which resulted in the discussed tunability. SEM images acquired across the sample surface on the best optimized sample show variation of Ag morphology from nearly continuous film to Ag nanocolumns (dia-135 nm) and then to Ag nanoislands of varying size (26–83 nm) with the variation in height from substrate bottom edge. Surface plasmon resonance (SPR) peak of this Ag nanostructure has been found to shift to longer wavelength and to broaden with the increase of thickness across the substrate surface. The estimated band gap values of the Ag nanostructure are non-zero which reveals its dielectric like dispersion behavior. Thickness and optical constants at various locations on the best optimized sample have been estimated through spectroscopic ellipsometry measurements and the obtained results have been validated with measured transmission spectrophotometry spectra. Three different ellipsometry models have been tried to fit the ellipsometry data of such grown ultrathin film consisting of Ag nanoislands/nanocolumns. An effective media consisting of the mixture of bulk Ag, dielectric media represented by Lorentz oscillator and air was found to be the best to describe the disperision behavior of the deposited Ag film. The dielectric like dispersion behavior of Ag ultrathin film has been ascribed to localized surface Plasmon resonance (LSPR) effect of Ag nanoislands in optical wavelength region. Due to the gradual variation of thickness and optical constants across the film, the optimized film exhibits variation in average optical transmittance (600–1000 nm) from 1.1% to 91% across 40 mm distance which demonstrates its potential for application as variable optical transmission attenuator. Finally, this novel deposition flux constrainment technique has been regarded as an effective method for fabrication of tunable Ag nano-morphologies for optical and surface plasmonic applications.

This work articulated the multi-pass, gas tungsten arc welding by adopting pulsating current for joining nitrogen-enhanced, low-carbon austenitic stainless steel, AISI 316L(N). An austeno-ferrite stainless steel (ER2594) and an over-alloyed (ERNiCrMo-3) fillers were employed to join 6-mm-thick plates of AISI 316L(N). Acicular and lathy ferrite in the weld zone of ER2594 and the occurrence of secondary phases in the fusion zone of over-alloyed filler were observed. The notch tensile strength data attested that the joint strength was greater for the welds employing an over-alloyed filler. This study also affirms that the welds obtained with ER2594 filler resulted in better impact toughness (144 J) compared with ERNiCrMo-3 filler and base metal. Also the notch impact toughness of ER2594 weldment is increased to 60% in comparison with that of candidate metal. Corrosion studies were also performed by exposing the coupons in a eutectic salt mixture comprising of 40%K2SO4-60%NaCl for 50 cycles at 650 °C. It is observed that the weld zone employing over-alloyed filler experienced better high-temperature corrosion resistance compared to the base metal. The specific results of this investigation will be of greater demand to the nuclear and marine applications utilizing these joints.

The growth of metal nanocrystals within polymer nanowires deviates from the conventional nucleation-growth process as movements of nucleated metal nanocrystals are hindered due to simultaneous grow...

In this study, the effect of aluminum (Al) addition to a manganese (Mn) steel Fe-12Mn-0.5C in regard to the change in stacking fault energy (SFE) and the consequent evolution of deformation microstructure and texture were investigated during cold rolling. An analysis of the texture and microstructure was performed to understand the deformation micro-mechanisms. Deformation micro-mechanisms were substantiated by the estimation of dislocation density and the arrangement of dislocations in the deformed microstructure by X-ray line profile analysis, which revealed significant changes in the dislocation structure with the addition of Al. Three stages of deformation mechanism were observed in all Al-added compositions. In the early stages of deformation, slip as well as twinning prevailed. In the intermediate stage, twinning took over completely and at large strains, macroscopic shear bands became the dominant deformation mode. An increase in the propensity of nanometer-sized deformation twins was observed with rolling strain. However, the addition of Al decreased the overall twin fraction in the deformed microstructure. The theoretical twinning stress was calculated to explain the crucial role of SFE on the occurrence of deformation twins in these steels. The deformation texture was predominantly of the brass type for all the Al-added compositions; however, appreciable differences were seen with Al content. The 〈111〉//ND γ-fiber, which develops in Al-free Fe-12Mn-0.5C, completely disappeared in 3 wt pct Al-containing material.

Monoclinic molybdenum trioxide (β-MoO3) nanostructures (shaped like nanoribbons: NRs) were grown on Si(1 0 0), Si(5 5 1 2) and fluorine-doped tin oxide (FTO) by molecular beam epitaxy (MBE) technique under ultra-high vacuum (UHV) conditions. The dependence of substrate conditions and the effective thickness of MoO3 films on the morphology of nanostructures and their structural aspects were reported. The electron microscopy measurements show that the length and the aspect ratio of nanostructures increased by, 260% without any significant change in the width for a change in effective thickness from 5 nm to 30 nm. NRs are grown along 〈0 1 1〉 for all the effective thickness of MoO3 films. Similarly, when we increased the film thickness from 5 nm to 30 nm, the optical band gap decreased from 3.38 ± 0.01 eV to 3.17 ± 0.01 eV and the local work function increased from 5.397 ± 0.025 eV to 5.757 ± 0.030 eV. Field emission turn-on field decreased from 3.58 V/μm for 10 μA/cm2 to 2.5 V/μm and field enhancement factor increased from 1.1 × 104 to 5.9 × 104 for effective thickness variation of 5–30 nm β-MoO3 structures. The β-MoO3 nanostructures found to be much better than the α-MoO3 nanostructures due to low work function, low turn on field and high field enhancement factor, and are expected to be useful applications.

We report a simple reduction of molybdenum oxide (β-MoO3) grown on reconstructed Si(100) by thermal annealing in ultra-high vacuum (UHV) using molecular beam epitaxy (MBE). By increasing the substrate temperature during deposition or the annealing temperature after growth, the morphologies of as-deposited structures were found to vary from nanoribbons (NRs) of β-MoO3 to nanoparticles (NPs) of Mo. The change in morphologies have been associated with a structural transition from β-MoO3 to MoO2 at 400 °C and MoO2 to Mo at 750 °C. The in-situ X-ray photoelectron spectroscopy (XPS) measurements revealed a shift of the Mo 3d peaks towards lower binding energies, representing the reduction in Mo oxidation states until a pure Mo 3d peak at 750 °C was observed. The ex-situ KPFM measurements showed a decrease in the local work function (Φ) (from ≈ 5.27 ± 0.05 eV to ≈ 4.83 ± 0.05 eV) with increasing substrate temperature. A gradual reduction of the band gap from ≈ 3.32 eV for β-MoO3 NRs to zero band gap for Mo NPs is also observed during the annealing up to 750 °C.