Indian Institute of Technology Ropar

Reinforced concrete (RC) frame-shear wall building systems are widely adopted in India due to their high strength and stiffness, making them effective in resisting lateral seismic forces. However, their performance during extreme seismic events has revealed limitations, particularly in terms of structural resilience. Foundation rocking is a novel approach for enhancing the seismic resilience and has caught the eye of several researchers. However, allowing the foundation to rock will result in the increase of displacement caused by rotations at the base of the foundation which may cause permanent settlements depending on the underlying soil properties. This study investigates the potential of foundation rocking as an innovative strategy to enhance the seismic resilience of high-rise RC frame-shear wall buildings. Four varying degrees of foundation rocking that can be allowed without compromising the integrity of the building system were analyzed to ensure structural integrity while improving performance. The seismic behavior was assessed through key parameters, including maximum superstructure displacement, peak moment at the foundation, settlement of underlying soil, self-centering ratio, and tipping over ratio. Results demonstrate that the displacements induced by rocking remain within the permissible limits outlined in Indian standards. Additionally, rocking foundations effectively reduce peak moments during seismic events, thereby lowering the seismic demand on the superstructure. The calculated self-centering and tipping over ratios confirm adequate safety margins for all considered scenarios. Overall, the study concludes that controlled foundation rocking significantly enhances the seismic resilience of RC frame-shear wall systems, offering a promising direction for earthquake-resistant construction in India.

In rock dynamics problems, evaluating the dynamic characteristics of a jointed rock mass during the propagation of shear waves generated by seismic and other explosive loading is of utmost importance. The effectiveness of natural rubber latex (NRL) as a dampening layer in rock joints has been investigated. The effectiveness of joint spacing on the dynamic response of rocks has been studied using gypsum plaster samples with one to four horizontal joints layered with a 3-mm-thick NRL filling. The dynamic characteristics were evaluated using resonant column (RC) and cyclic torsional shear (CTS) tests across varying strain amplitudes, confining pressures, and loading frequencies. The results revealed that NRL-filled joints consistently exhibited reduced shear modulus and enhanced damping ratios compared to plain jointed specimens. The influence of joint spacing, confining pressure, strain amplitude, and frequency was quantified using regression analysis, showing that NRL-filled specimens were more responsive to joint spacing, while plain joints were more affected by strain amplitude and confining pressure. The viscoelastic nature of NRL contributed to improved energy dissipation, particularly under cyclic loading, in which CTS tests showed greater damping sensitivity than RC. The Ramberg–Osgood and modified hyperbolic models were used to fit the experimental results acquired from RC and CTS tests. These findings confirm that incorporating NRL in jointed systems can substantially improve attenuation characteristics under seismic-type loads. This study offers a practical material-level solution for mitigating dynamic amplification in jointed rock masses, providing a foundation for further exploration in field-scale geotechnical applications.

Inorganic nanoparticles are widely used as sacrificial templates for the synthesis of porous carbons due to their good thermal stability, characteristic shapes, tunable sizes, compatibility with carbon precursors, and lower cost and toxicity than conventional silica-based templates. Their use not only ensures the development of hierarchical porosity but also the creation of short-range graphitic domains in the carbon matrix. These qualities make porous carbons suitable for different applications, including adsorption, separation, catalysis, and energy storage and conversion. Within the series of inorganic nanoparticle templates, metal oxides such as MgO, ZnO, Fe2O3, Fe3O4, and MnO2, and alkali metal salts such as NaCl and KCl stand tall as templates. They are thermally and structurally stable, do not react with the carbon precursor, and do not require high-cost, harsh removal methods such as HF washing. This review provides up-to-date discussions of metal oxides (MgO, ZnO, Fe2O3, Fe3O4, and MnO2) and metal salts (NaCl, KCl, and composite salts) to produce porous carbons and addresses other aspects of their structures. This is a focused review that critically analyzes the recently published literature and will serve as a guiding framework for the future design and development of porous carbons.

This study combines batch adsorption experiments and surface complexation modelling to investigate the interactions of arsenate [As(V)] and arsenite [As(III)] with agricultural soils from an arsenic (As) contaminated district of Punjab, India. Batch adsorption studies were conducted to investigate the impact of contact time, As loadings, ionic strength and solution pH on As retention under conditions representative of the regional environment. As adsorption was significantly higher in surface soil layers than in bottom layers, largely due to variations in surface area, organic matter content, pH, and mineralogical components. Experimental data were interpreted using a generalized composite triple layer model (GC-TLM), representing the average surface reactivity of the natural soil assemblage. Modelling results indicate that As(V) predominantly forms inner-sphere surface complexes, whereas As(III) forms both inner and outer-sphere complexes. The model successfully reproduced adsorption isotherms and pH-edge behaviour within reasonable RMSE, demonstrating its applicability to natural soils. These findings improve the mechanistic understanding of As-soil interactions and provide a basis for predicting As mobility in agricultural soils of Punjab.

Advances in soil moisture monitoring techniques and sensor networks have made data assimilation a powerful approach for estimating evapotranspiration (ET). The commonly used simple water balance (SWB) model provides reliable ET estimates within data assimilation frameworks; however, it often neglects the influence of ET on vertical fluxes. While this assumption may be valid during drying periods in low-drainage soils, it is less appropriate for soils with high hydraulic conductivity. This study introduces a comprehensive water balance (CWB) model that explicitly accounts for ET-driven percolation. The model captures the effect of ET on vertical fluxes by comparing soil water depletion with and without ET, thereby highlighting the role of root water uptake (RWU) in controlling percolation. The CWB model, coupled with an ensemble Kalman filter, predicts daily ET using soil moisture sensor data across different soil types. Within this framework, RWU is treated as the observable variable for state updating. Model performance was evaluated against the conventional SWB model under varying drainage conditions. For loamy sand, the CWB model was independently validated using weighing lysimeter measurements. Results demonstrate that the CWB model outperforms the SWB model, particularly in coarse-textured soils, reducing ET estimation error by up to 45% and achieving higher accuracy (NSE = 0.918 vs. 0.727). Sensitivity analyses incorporating sensor uncertainty show that fine-textured soils exhibit lower sensitivity to measurement errors, resulting in more robust ET estimates. These findings underscore the importance of incorporating vertical flux effects to avoid ET underestimation, especially in highly permeable soils. Keywords: Water balance model, vertical flux, evapotranspiration, Ensemble Kalman filter, root water uptake.

Abstract The main goal of this article is to establish Hölder stability estimates for the Calderón problem related to a relativistic wave equation. The principal novelty of this article is that the partial differential equation (PDE) under consideration depends on three unknown potentials, namely a temporal dissipative potential A 0 , a spatial vector potential A and an external potential Φ. Moreover, the PDE is posed in an infinite waveguide geometry <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">Ω</mml:mi> <mml:mo>=</mml:mo> <mml:mi>ω</mml:mi> <mml:mo>×</mml:mo> <mml:mrow> <mml:mrow> <mml:mi mathvariant="double-struck">R</mml:mi> </mml:mrow> </mml:mrow> </mml:mrow> </mml:math> and not on a bounded domain. For our proof it is essential that the potentials are time-independent as a key tool in this work are pointwise estimates for the Radon transform of the vector potential <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mi class="MJX-tex-calligraphic">A</mml:mi> </mml:mrow> <mml:mo>=</mml:mo> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mi>A</mml:mi> <mml:mn>0</mml:mn> </mml:msub> <mml:mo>,</mml:mo> <mml:mrow> <mml:mi mathvariant="sans-serif">i</mml:mi> </mml:mrow> <mml:mi>A</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> and external potential Φ. Furthermore, the demonstrated stability estimates hold for a wide range of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>H</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> Sobolev scales and a main contribution is to explicitly determine the dependence of the involved constants and the Hölder exponent on the Sobolev exponents of the potentials <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>A</mml:mi> <mml:mn>0</mml:mn> </mml:msub> <mml:mo>,</mml:mo> <mml:mi>A</mml:mi> </mml:mrow> </mml:math> and Φ.