Indian Institute of Technology Mandi

Renu, Katin K., Chakraborti S., Sharma A., Muruganathan M., Kumar R.

Ranaut D., Channarayappa S.K., N A., Stenning G.B., Adroja D.T., Mukherjee K., Jaiswal-Nagar D.

Chamarthi G., Patel A., Pratap R.

Kumar S., Betal A., Kumar A., Chakkar A.G., Kumar P., Kwoka M., Sahu S., Kumar M.

Dhir A., Shagun S.

AbstractA dansyl‐isoniazid conjugate (DISH) is designed and synthesized which exhibits Aggregation‐Induced Emission (AIE) in MeOH : H2O (20 : 80). This AIE Material is utilized for detection of different antibiotics having carboxylic acid, amide and thioamide functionalities. The material shows a multimodal recognition behaviour having maximum affinity with a fluorescence intensification (236 %) (φ=0.68) on addition of 2.0 μM levofloxacin (LEV) whereas the quenching of fluorescence emission is observed on addition of prothionamide (PTH) (8.0 μM). To test the practical application of the DISH, we performed smartphone‐based detection wherein RGB colour picker app is used to study the colour variation of probe in urine samples spiked with same concentration of LEV (2.0 μM) and PTH (8.0 μM).

Sharma D., Mittal K., Kaur D., Ray R.K., Mohanty R.K.

Bhardwaj S., Pandey S.K.

Moharana A., Gaur A., Vaish R.

ABSTRACTThe coupling of photocatalysis and piezocatalysis has gained significant interest among researchers. In this study, we present the photo‐piezocatalytic activity exhibited by bismuth titanate (Bi4Ti3O12) glass‐ceramics (BTO‐GC). BTO‐GC samples were prepared in a glass system of 40Bi2O3‐40B2O3‐20TiO2 (in mol %) by using the melt‐quench technique. The catalyst was characterized by the X‐ray diffraction (XRD) technique and Raman spectroscopy for its structure and phase analysis. Surface morphology and chemical composition were analyzed by scanning electron microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS), respectively. The catalytic performance of BTO‐GC was evaluated in photocatalysis, piezocatalysis, and photo‐piezocatalysis processes. Methylene blue (MB) dye degradation was evaluated by using a UV–Vis spectrophotometer. A maximum degradation performance of ~86% was achieved in the solar light photocatalysis process. This study highlights the synergistic photo‐piezocatalytic performance in glass‐ceramics and advances the understanding of its underlying mechanism.

Pant H., Singh S., Brar J., Sharma P., M B., Kuga K., Takeuchi T., Bindu R.

Abstract We have studied the origin of zero volume expansion below the Curie temperature ( T c ), variable range hopping (VRH) behavior using structural, magnetic, transport and thermal studies on the oxygen deficient double perovskite NdBaCo2O 5 + δ ( δ ∼ 0.65). The valence state of Co ions and the possible properties exhibited by such compound were studied using electronic structure calculations for δ = 0.75. Careful investigation of structure shows that the compound stabilizes in tetragonal structure (P4/mmm) having 2 a p × 2 a p × 2 a p (222) superstructure, where a p is the cubic perovskite lattice parameter. The compound exhibits a minimum in resistivity, ferromagnetic (FM) and ferrimagnetic (FeM) transitions around 375 K, 120 K ( T c ) and 60 K, respectively with signature of Griffiths phase above T c . Our detailed structural analysis suggests signature of the onset of the above magnetic transitions at temperatures well above its stabilization at long range level thereby leading to VRH behavior. The observed zero thermal expansion in volume below T c appears to be due to competing magnetic interactions within and between the magnetic sublattices. Our electronic structure calculations in FM and FeM configurations show (a) Co ions stabilize in intermediate spin (IS) state, having oxidation state less than +3, (b) half metallicity, (c) the behavior of the density of states is in line with the resistivity results, and (d) unusually high orbital angular moment in Co ions with inclusion of spin orbit coupling (soc). Our results show the possibility of coupling between magnetism and ferroelectricity. We believe that our results especially on the valence state of the Co ion, zero thermal expansion in volume, short range magnetic orderings and the connection between different degrees of freedom will be helpful in clearing the ambiguities existing in literature on the nature of magnetism and thereby aiding in designing new functionalities by maneuvering the strength of soc.

Choudhary R., Sharma V., Dhanya J., Gade M.

In this study, a new ground motion model (GMM) is developed for the Western Himalayan region. We have addressed the challenges arising in the regional ground motion model development for data-sparse regions by implementing the transfer learning methodology. The comprehensive NGA-West2 and NESS databases are chosen for the global source model and the database of the Western Himalayan region for the regional target model. The knowledge learned from the source model is transferred to the regional-level model in the form of weights and biases between the initial layers. The corresponding methodology is observed to improve the performance of the regional model, especially in the ranges of limited recorded information. The newly proposed regional model is observed to capture the general physical trends with respect to path and site. Furthermore, the nonlinear site effects are also captured by the model. The demonstration of the model in hazard application is also performed, and a discussion on the implication of de-clustering on resultant seismic hazards for a typical site in the region is also made in this work.

Banerjee P., Kulkarni H.V., Veach A.M., Nagaraja T., Pathak P., Das S.R., Datta S.

IntroductionThe availability and mobility of phosphorus (P) in soils play a crucial role in effectively managing agricultural activities and maintaining healthy soils. Several parameters including soil texture, pH, elemental and mineralogical composition, moisture content, and soil organic matter (SOM) are crucial in controlling the movement of P in soils. This study focuses on assessing geochemical properties of soils from a pristine prairie grassland and an agriculturally dominated land, and their influence on soil P mobility.MethodsSurface soils were collected from two locations, Konza Prairie Biological Station (KBPS) located in Manhattan (Kansas) which is a native grassland ecosystem, and agricultural land in town of Hays (Kansas).ResultsResults showed that the KPBS soils contained lower water-extractable phosphate (PO43—) concentrations (0.2 ± 0.7 mg/kg) than soils from Hays (1.3 ± 2.4 mg/kg). Bio-available P measured as Bray-P were also lower in KPBS (14.3 ± 7.0 mg/kg) relative to Hays (23.0 ± 23.7 mg/kg). Soils from both the sites contained water-extractable calcium, magnesium and potassium as a primary soluble component likely from carbonate minerals in these calcareous soils. The SOM concentrations measured as loss on ignition (LoI) were greater in KPBS (9.9% ± 1.8%) relative to Hays (5.3% ± 1.7%). Water extractable soil organic carbon (WE-SOC) concentrations were also greater for KPBS (651 ± 274 mg/kg) relative to Hays (288 ± 267 mg/kg). Optical spectroscopic analyses using absorbance and fluorescence properties revealed that the water-extractable SOM in these soils was mainly of terrestrial origin, plant-derived, aromatic, and contained humic-like substances. The intensities of fluorescence peaks A, C, and M, and specific UV absorbance at 254 nm (SUVA 254) of both soils correlate strongly with the Bray-P concentrations, indicating that the source of SOM plays a vital role in controlling soil P mobility.ConclusionThese findings indicate that natural prairie grassland soils contained lower P concentrations that are primarily insoluble in water and associated with humic and fulvic-like SOM.

Sana E., Kritika, Kumar A., Robson E., Prasanna R., Kala U., Toll D.G.

Himachal Pradesh, a northern state of India, experienced unprecedented heavy rainfall between July and August 2023 that triggered several devastating and fatal landslides across the state. This paper presents the findings of two key studies that aim to further our understanding of the failure trends and mechanisms that occurred during the 2023 monsoon season. Firstly, the systematic mapping of the landslides using satellite imagery and field mapping techniques to identify trends in the landslide characteristics was conducted. Approximately 6500 landslides were mapped that were triggered during the 2023 monsoon season across an area of approximately 3100 km2 in the Mandi and Kullu Districts. The key failure mechanisms for these landslides are presented and analysed. It was found that the most critical combination for slope failures in the Himachal Pradesh region consists of sandstone lithology. Slides were the most common observed types of failures. Additionally, the rainfall anomaly index clearly highlighted the change in the trend of rainfall in the mountainous region indicating the evident impact of climate change. Secondly, a coupled hydro-mechanical finite element analysis to investigate the detailed mechanisms of failure for an exemplary slope was performed. The numerical modelling revealed that the progression of a wetting front brought about by continued rainfall infiltration caused a reduction in the soil suction and the resulting loss of the shear strength of the soil forming the slope along the potential slip surfaces. The studies presented in this paper significantly contribute to knowledge of rainfall-triggered landslide mechanisms in Himachal Pradesh.

Salwahan S., Abbas S., Tridane A.

In this paper, we examine a modified susceptible–infected–treatment–recovered (SITR) model. The SITR model is assumed to be a periodically switched system, where two parameters, i.e., transmission rate and treatment rate, are periodically switched. In the first part of the article, we analyze the stability of the switched model in the presence of periodic switching. Moreover, with the periodic switching, we obtain a discontinuous dynamical system where the optimal vaccination control cannot be calculated directly using Pontryagin’s maximum principle. Hence, an optimal control problem of the periodically switched system is formulated by modifying Pontryagin’s maximum principle. The aim is to study the optimization of control strategies for infectious disease outbreaks in a dynamic and resource-limited environment. Finally, several numerical examples are provided to support the results discussed.

Gupta A., Srivastava C.K., Bhushan B., Behera L.

EEG microstates offer a unique window into the dynamics of emotional experiences. This study delved into the emotional responses of happiness and sadness triggered by music videos, employing microstate analysis and eLoreta source-level investigation in the alpha band. The results of the microstate analysis showed that regardless of gender, participants during happy music video significantly upregulated class D microstate and downregulated class C microstate, leading to a significantly enhanced global explained variance (GEV), coverage, occurrence, duration, and global field power (GFP) for class D. Conversely, sad music video had the opposite effect. The eLoreta study revealed that during the happy state, there was enhanced CSD in the central parietal regions across both genders and diminished functional connectivity in the precuneus for female participants compared to the sad state. Class D and class C microstates are linked to attention and mind-wandering, respectively. The findings suggest that (1) increased class D and CSD activity could explain heightened attentiveness observed during happy music, and (2) increased class C activity and functional connectivity could explain enhanced mind wandering observed during sad music. Additionally, female participants exhibited significantly higher mean occurrence than males, and the sad state showed significantly higher mean occurrence than the happy state.

Malik M., Saxena P.

Material extrusion-based additive manufacturing has gained significant attention due to its ability to fabricate complex shapes with reduced material waste compared to conventional methods. This technology is still in its early research phase, which includes optimizing the process parameters for 3D printing composites using continuous and short fiber-reinforced thermoplastics. Basalt fiber has emerged as a promising eco-friendly material that can replace glass and Kevlar® fibers due to its lower cost and environmentally friendly properties. The mechanical properties of the composites largely depend on the process parameters involved in the material extrusion technique. This study aims to experimentally analyze the effect of print resolution, nozzle speed, and hot-end temperature on material extrusion-based 3D-printed eco-friendly continuous basalt fiber (CBF)-reinforced polylactic acid (PLA) composites and to optimize the printing parameters for achieving enhanced mechanical properties. Impact tests and short-beam shear tests were conducted on specimens printed with different printing parameters to evaluate their effect on impact energy absorption and interlaminar shear strength (ILSS). The results showed that print resolution is the most efficient factor to improve impact strength and interlaminar shear strength of the composites, followed by nozzle speed and hot-end temperature. The optimum results were obtained at a print resolution of 0.25 mm, nozzle speed of 30 mm/s, and hot-end temperature of 210 °C. The fractured surfaces of the failed specimens after testing were analyzed using scanning electron microscopy (SEM) to confirm the micro-failure modes of the specimens.