Indian Institute of Technology Gandhinagar

Low voltage (<1V) bi-directional and symmetric electrostatic discharge (ESD) protection devices are essential for system level ESD protection of low voltage electronics such Low voltage GPIO for MCU, Sub-20nm I/O’s, and potentially for next gen interfaces USB3.2 Gen2, Thunderbolt 4. Here, a triangular barrier designed Silicon NIPIN (n ⁺ -i-p ⁺ -i-n ⁺ ) punch-through diode with variable voltage <0.5V to 2V is proposed for low-voltage system level ESD protection. The NIPIN diode utilizes the sub-bandgap voltage impact ionization to enable the ultra-low voltage breakdown. The control over the breakdown voltage is demonstrated via TCAD simulations by controlling the lengths of intrinsic, and p ⁺ -doped regions and the doping of p ⁺ -doped region. Finally, standoff voltage and clamping voltages are compared with other low voltage protection devices and demonstrate near ideal voltage performance of the NIPIN protection device. Such a low voltage ESD protection with low clamping voltage is a critical development for low-voltage electronics.

This work presents a computationally efficient approach for extracting compact model parameters with minimal training requirements. Bayesian optimization (BO) is employed in multiple stages to predict the optimum compact model parameters. Initially, the methodology is applied to the MIT virtual source model (MVS 2.0) for extremely thin silicon-on-insulator (ETSOI) devices, nanosheet FETs (NsFETs), and $\text{MoS}_{\text{2}}$ -based 2-D material-based FETs (2DFETs). Subsequently, it is demonstrated on the Berkeley short-channel IGFET model (BSIM) common multigate (CMG) compact model for NsFETs. Through sequential processing, adaptive sampling, successive domain reduction, and fine-tuned objective functions, the framework achieves precise and efficient fitting of both global and local model parameters across a range of devices, all in a reduced number of iterations, irrespective of the compact model used.

Hong–Ou–Mandel (HOM) interferometry has emerged as a valuable means for quantum sensing applications, particularly in measuring physical parameters that influence the relative optical delay between photon pairs. Unlike classical techniques, HOM-based quantum sensors offer higher resolution due to the intrinsic dispersion cancellation property of correlated photon pairs. Due to the use of single photons, HOM-based quantum sensors typically involve a large integration time to acquire the signal and subsequent post-processing for high-resolution measurements, restricting their use for real-time operations. Based on our understanding of the relationship between measurement resolution and the gain medium length that produces photon pairs, we report here on the development of an HOM-based quantum sensor for high-precision group index measurements. Using a 1 mm long periodically poled KTP (PPKTP) crystal for photon-pair generation, we have measured the group index with a precision of ∼6.75×10−6 per centimeter of sample length at an integration time of 100 ms, surpassing the previous reports by 400%. Typically, the measurement range reduces with the increase in the resolution. However, using a novel scheme compensating photon delay due to group index changes stepwise with an optical delay stage, we have measured the group index variation of PPKTP crystal over a range of 3.5 × 10⁻³ for a temperature change from 25 to 200 °C, corresponding to an optical delay adjustment of ∼200 μm while maintaining the same precision (∼6.75×10−6 per centimeter of sample length). The current results establish the usefulness of HOM-interferometer-based quantum sensors for fast, precise, and long-range measurements in various applications, including quantum optical coherence tomography.

Ozone pollution has become a burgeoning issue in urban and downwind regions because of increased anthropogenic emissions of ozone precursors. Anthropogenic activities are increasing across the foothills of the Himalayas, and the region experiences elevated levels of ozone and poor air quality, which impacts the fragile ecosystem of the Himalayas. To assess ozone pollution and drive chemistry, we have conducted ground-based O3 measurements in the Doon Valley at the Graphic Era (77.99° E, 30.27° N, 600 m above mean sea level) since April 2018. Maiden measurements showed significant ozone buildup during noontime (20–100 ppbv), with the highest levels occurring during spring/premonsoon and a secondary enhancement occuring during postmonsoon. The Copernicus Atmosphere Monitoring Service (CAMS) reanalysis successfully reproduced 80–90% of the total variability in the noontime ozone. The maximum daily 8-h ozone (MDA8) index exceeded the threshold of 50 ppbv about 60% of the days during the April—June period. Such elevated levels are due to intense photochemistry owing to higher solar insolation and higher levels of precursors transported from upwind regions where biomass burning is intense during this season. The contribution of biomass burning over the Haryana-Punjab region is estimated to be ~35–56% at noontime ozone during the premonsoon season. The impacts of crop residue burning were, however, weaker during the postmonsoon season due to seasonal changes in wind circulation and lower solar radiation. An analysis with satellite observations of precursors showed that ozone formation is in the transition or VOC-limited chemical regime; hence, the emission of both NOx (oxides of nitrogen) and volatile organic compounds (VOCs) are to be reduced to mitigate ozone pollution over the foothills of the central Himalayas. Our assessment of ozone shows the intertwined role of photochemistry and transport from regional biomass burning.

Key message Hybridization barriers in Brassicaceae play a pivotal role in governing reproductive success and maintaining speciation. In this perspective, we highlight recent advances revealing the intricate molecular mechanisms and the interplay among key players governing these barriers. Abstract Recent studies have shed light on the molecular mechanisms that govern hybridization barriers in Brassicaceae. The interplay between pollen coat proteins, stigmatic receptors, and signaling peptides plays a crucial role in determining the success of pollination. At the core of this system, autocrine stigmatic RALF peptides (sRALF) maintain the stigmatic barrier by activating the FERONIA (FER) and ANJEA (ANJ) receptor complex, triggering the RAC/ROP-RBOHD pathway and subsequent reactive oxygen species (ROS) production. It is now established that incompatible pollen rejection is mediated by two parallel pathways: the FER-RAC/ROP-RBOHD pathway, which generates ROS, and the ARC1-mediated pathway, which degrades compatible factors required for pollen growth. Conversely, compatible pollen overcomes the stigmatic barrier through the action of pollen coat proteins (PCP-B) and paracrine pollen-derived RALF peptides (pRALF), which compete with autocrine sRALF for receptor binding, enabling successful pollen hydration and tube penetration. The "lock-and-key" mechanism involving sRALF and pRALF provides species-specific recognition of compatible pollen. These findings offer valuable insights into the molecular basis of hybridization barriers and open new possibilities for overcoming these barriers in interspecific and intergeneric crosses within Brassicaceae, with potential applications in plant breeding and crop improvement. Future research should focus on elucidating the evolutionary dynamics of these signaling pathways and exploring their manipulation for crop breeding purposes.

Nanotechnology is transforming stem cell medicine by enabling precise isolation, controlled differentiation, and targeted therapies across various medical domains. This review highlights key advancements, including the use of nanomaterials like...

To date, the bestmethodsfor estimating the growth of mean values of arithmetic functions rely on the Voronoï summation formula. By noticing a general pattern in the proof of his summation formula, Voronoï postulated that analogous summation formulas for $\sum a(n)f(n)$ can be obtained with ‘nice’ test functions f ( n ), provided a ( n ) is an ‘arithmetic function’. These arithmetic functions a ( n ) are called so because they are expected to appear as coefficients of some L -functions satisfying certain properties. It has been well-known that the functional equation for a general L -function can be used to derive a Voronoï-type summation identity for that L -function. In this article, we show that such a Voronoï-typesummation identity in fact endows the L -function with some structural properties, yielding in particular the functional equation. We do this by considering Dirichlet series satisfying functional equations involving multiple Gamma factors and show that a given arithmetic function appears as a coefficient of such a Dirichlet series if and only if it satisfies the aforementioned summation formulas.

The field of metallic glasses has been an active area of research owing to the complex structure–property correlations and intricacies surrounding glass formation and relaxation. This review provides a thorough examination of significant works that elucidate the structure–property correlations of metallic glasses, derived from detailed atomistic simulations coupled with data-driven approaches. The review starts with the theoretical and fundamental framework for understanding important properties of metallic glasses such as transition temperatures, relaxation phenomena, the potential energy landscape, structural features such as soft spots and shear transformation zones, atomic stiffness and structural correlations. The need to understand these concepts for leveraging metallic glasses for a wide range of applications such as performance under tensile loading, viscoelastic properties, relaxation behavior and shock loading is also elucidated. Finally, the use of machine learning algorithms in predicting the properties of metallic glasses along with their applications, limitations and scope for future work is presented. Graphical abstract

DNA's extraordinary potential reaches far beyond its role as a carrier of genetic information. It serves as a remarkably adaptable structural foundation for constructing intricate nanostructures with a diverse range...

The Andaman and Nicobar Islands are rimmed by discontinuous fringing reef that is in general wider on western margin vs the eastern margin. This study characterizes the facies updip from the modern fringing reefs to the present shoreline of south Andaman and Swaraj Dweep, and describes in detail the coral terraces/carpets within and above the inter-tidal zone representing the Holocene Fringing reef. Field studies, satellite, and drone datasets have been utilized to map different facies, that include: coralgal boundstone, biodetrital-grainstone, beachrock, and coralgal rudstone. Multiple exposed microatolls as well as coral terraces (coral carpets) of Acropora and Porites (dated 8.7-8.4 ka BP) have been identified within the intertidal zone (Radhanagar Beach, Swaraj Dweep) indicating that Holocene fringing reef have down-stepped offshore to the current location of modern fringing reefs owing to either tectonics or eustasy. The eustatic sea-level fluctuations are relatively well established for the Holocene and we compute the tectonic uplift rates utilizing the stream-power-incision and linear-inversion model. A tectonic uplift rate of ~ 0.05 mm/yr (for Swaraj Dweep) during the past 100 ka is estimated, while taking into account a wide range of erodibility indexes and response time intervals. It is identified that the computed uplift rate is an amalgamation of the coseismic deformation along with the interseismic and aseismic surface deformation. Thus, not all exposed coral terraces/microatolls are exposed due to coseismic deformation (for example uplift in parts of Andaman due to earthquake in 2004). The average long-term uplift rates are a magnitude lower than the eustatic sea-level fall rates during Holocene, thus, we suggest that most of the Holocene fringing reefs are exposed due to eustatic sea-level fall and down-stepped to the current location of the modern fringing reefs. This would entail that the eustatic sea-level change rates would play a significant role in determining future of the modern fringing reef (catch-up vs keep up vs give up), and the coastal morphology of south Andaman and Swaraj Dweep, with implications for coastal inundation and stability in the scenario of climate change.

Thermal radiation blockage to the pool surface plays a major role in assessing the fire growth and heat feedback to the pool surface and thereby intensity of pollution to the environment. In this work, large eddy fire simulations are performed to quantify the thermal radiation blockage to the pool surface of 0.6 m n-heptane double pool fires (DPF). The interspace between the two pools is varied from 0 to 0.6 m. The results of the air entrainment show that the considered double pool configuration is radiation dominated irrespective of the separation distances between the pools. The predicted heat feedbacks are in good agreement with the experimental results. A radiation influencing zone (RIZ) is introduced based on the percentage of the radiation contribution from the flame. RIZ is directly proportional to the flame height. Based on the opacity through the RIZ, the thermal radiation blockage is calculated. The blockage of radiation from standalone fire to double fire increased to 20%. The calculated radiative heat flux to the pool surface is in good agreement with the reported measurements. In addition, the maximum deviation between calculated and measured heat fluxes of the studied DPF is 6.8%. Further, the accuracy of the present methodology is shown better than the reported literature estimations.

The lapidary industry using different stone raw materials is one of the hallmark technological innovations of the Harappan civilization (~ Indus, Indus-Sarasvati). The Harappans perfected the technology, which is traced back to the Neolithic Mehrgarh, wherein advanced rotary drilling mechanisms were used. It may be observed that the early societies at Mehrgarh often procured raw materials from far beyond, indicating a clear establishment of long-distance trade. This was further expanded during the Chalcolithic period, culminating in the Harappan civilization aided through better procurement and distribution networks. The Harappan beads attained popularity due to their uniqueness and superior quality. They were perforated by a material known as “ernestite”, a harder stone enabling a smooth surface. Harappans used rotary aids for drilling, with materials like hollow and solid copper drills and pecking techniques for smaller and shorter beads. The legacy of the Harappans continued during the late Harappan and the historical periods. However, we witnessed advancements in the drill bits during the historical period, with the single- and double-tipped diamond drills replacing the ernestite drills for faster drilling of stone beads. Slowly, the glass beads took over the place of stone beads, and attention was given to precious gemstones only. However, the stone bead industry lingered, and we find evidence of the traditional craft at Khambhat, Gujarat. This paper highlights some key aspects of Harappan bead drilling technology and its continuity into the late Harappan and historical period. In particular, the evidence from Vadnagar is discussed to understand the continuity.

The mix design of concrete is an important aspect that affects its strength and durability. This paper aims to revisit the existing mix design method given in IS 10262:2019 through a capacity-based approach. The approach involves identifying the possible failure modes in concrete and eliminating the undesirable ones leading to significant reduction in dispersion. This is accomplished by utilizing coarse aggregates that meet a specific minimum strength requirement or threshold (e.g., ~ 77 MPa for M95 grade of concrete), which is determined through a priori estimating the cohesion and friction angle of the concrete. The methodology to estimate the cohesion and friction angle from a single unconfined compression test is proposed based on the Mohr–Coulomb theory and using the orientation of failure plane of fractured specimen as a supplemental information from the same experiment. This paper also offers a simple and approximate test procedure to estimate the aggregate's compressive strength (~ 106 MPa in this mix design) reasonably which is essential for the capacity-based mix design. An experimental programme is also carried out to design the concrete mix using the proposed capacity-based approach. The results indicate that M95 concrete is achieved with a low standard deviation and coefficient of variation (~ 3%), falling in class of excellent quality control as per ACI 214R-11. This quality control is crucial in seismic structural design as variations in concrete strength is likely to negate the underlying principle of strong column–weak beam philosophy resulting in the triggering of undesirable shear modes of failure.

The investigation of established pharmaceutical agents for recalibrating usage strongly supplements new drug development. In this work, we have prepared coassembled complexes of acetazolamide (AZM) with the cationic peptide octaarginine (R8) in an attempt to enhance its potency and scope of use. R8 and AZM in different weight ratios coassemble into remarkable nano-and microstructures such as ribbons, sheets, and stick-like structures. A combination of FTIR, XRD, SEM, and DSC has been used to characterize the R8:AZM coassemblies. The sulfonamide SO 2 and NH 2 groups of AZM are associated with the guanidinium amine, free amine, and terminal carbonyl groups of R8 resulting in distinctive topologies. Treatment of Escherichia coli with the complexes results in a distinctive pattern of membrane disruption and pore formation. The R8:AZM coassemblies inhibit carbonic anhydrase and E. coli growth with greater efficiency compared to bare AZM. The 1:5 w/w complex leads to pronounced outer and inner membrane rupture and significantly restricts glucose uptake by E. coli. The ability of R8 and AZM to coassemble into a distinctive set of structures based solely on differences in their relative proportions and their engagement with E. coli as more than the sum of their parts are novel facets of R8 and AZM behavior and underscore a straightforward and elegant approach for enhancing the scope of use of small molecule drugs.