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Sign regularity preserving linear operators
No full textA matrix A?Rm�n is strictly sign regular/SSR (or sign regular/SR) if for each 1?k?min{m,n}, all k�k minors of A (or non-zero k�k minors of A) have the same sign. This class of matrices contains the totally positive matrices, and was first studied by Schoenberg (1930) to characterize Variation Diminution (VD), a fundamental property in total positivity theory. In this note, we classify all surjective linear mappings L:Rm�n?Rm�n that preserve: (i) sign regularity and (ii) sign regularity with a given sign pattern, as well as (iii) strict versions of these
Ballistic impact testing of acrylic and alumina thin-films
No full textHigh velocity projectiles cause damage to critical structures in space. Many of them travel at speeds of a few km/s to several hundred km/s. Such projectiles can punch through aircraft. In addition, bullets from modern weapons might reach 2.5 km/s. Spherical diamond projectiles are tested against Poly-Methyl-Metha-Acrylate (PMMA) and single-crystal corundum alumina (α-Al2O3) thin films. PMMA is created from two configurations: random and oriented along impact direction. The penetration velocity (V50) of PMMA and α-alumina are found to be near 400 m/s and 4.5 km/s, respectively. This study indicates that PMMA sandwiched between two layers of alumina can be produced, with a thickness that can be calculated using specific penetration energies (Ep∗) from the projectile radius, to stop most projectiles effectively
Characterizing condensation from humid air on wettability-engineered inclined surfaces through non-intrusive mapping of boundary layer
No full textVapor condensation from humid air is encountered in numerous industrial applications, often necessitating non-intrusive techniques to characterize and estimate heat and mass transfer performance. Schlieren imaging has emerged as a promising non-intrusive method for visualizing the density boundary layer that forms near the condensing surfaces. Eliminating the need for complex optical equipment, Background Oriented Schlieren (BOS) distinguishes itself from other Schlieren imaging techniques due to its simplicity and suitability for large-scale implementation. However, the technique warrants careful consideration of the pertinent flow configuration. Here we investigate the influence of surface inclination (relative to the vertical) and surface-wettability of the condensing surfaces on condensation from humid air using BOS. We map the density boundary layer during condensation on inclined surfaces with three distinct surface wettability, viz., superhydrophilic (SHPL), hydrophilic (HPL, the control) and superhydrophobic (SHPB). Our findings reveal that the SHPB surface exhibits enhanced condensation performance at higher inclination angles, while the SHPL surface demonstrates a decline in performance with increasing inclination. In contrast, the control surface displays minimal variation in density gradient fields across different inclinations. We further propose empirical correlations to predict the mass flux and condensation heat transfer coefficient (CHTC) based on the density boundary layer data obtained from the BOS images for various condenser surface wettability and inclination angles. These correlations show agreement within ±20% when validated against independently conducted condensate collection experiments, highlighting the potential of BOS as a reliable, non-intrusive tool for predicting condensation performance across a wide range of industrial applications
Hazards, Risks, and Conservation Measures: A Heritage Impact Assessment Geodatabase of Indus Civilization and Chalcolithic Sites of Gujarat, India
No full textThis research article aims to demonstrate the effectiveness of spatial analysis combined with Heritage Impact Assessments (HIA) for heritage management. It explains a geodatabase created for 508 archeological sites in Gujarat, India, related to Indus civilization and regional Chalcolithic cultures. The study area’s diverse geology made the sites ideal for the study. Each site in the geodatabase was provided with five attributes: Name, coordinates, hazard, risk, and conservation strategy. The names and coordinates were collected from field visits and previous works. Eight specific hazards have been selected in this study: soil erosion, floods, landslides, earthquakes, urban development, agriculture, vegetation growth, and minor vandalism. The hazard datasets were generated using various data and techniques such as satellite remote sensing, Geographic Information Systems (GIS), and Multi-Criteria Decision Making (MCDM), to name a few. Their quantitative risk to archaeological sites was calculated based on the impact on the structure or area of the sites. It was observed that out of the 508 sites, 464 are at risk from at least one of these factors. Excluding sites located in agricultural fields, 278 sites are still at risk. Finally, the database also provides conservation measures to mitigate risks involving various stakeholders such as academicians, heritage managers, and the public. These measures highlight the need for better practices, periodic monitoring, and the importance of using information technology by providing 3D layouts and models of a few sites
Data-driven real-time dynamic pricing for dual-PV-grid-powered bidirectional electric vehicle charging
No full textTransportation electrification is revolutionizing a progressive transition to attain net zero goals. Renewable energy integration emerges as a promising solution to reduce both the dependency on fossil fuels and control global warming. With the advancements in electric vehicle (EV) technology, formulating an effective EV charging tariff is crucial. Therefore, this work proposes a real-time dynamic tariff framework for a grid-tied solar photovoltaic (PV)-based EV charging system. It incorporates various system parameters, including the electricity market rates, battery state of charge levels, and the congestion rates at the charging station. The framework is flexible to operate in stand-alone mode during grid outages, which is not uncommon in developing countries, or during high electricity market rates. The principle objective is to incentivize EV users with an optimal choice of sources based on their availability and price levels. The proposed framework is scalable from household charging to a distribution licensee, significantly improving its financial health, or in forming a microgrid. The artificial neural network is employed to evaluate the system parameters in the framework. Furthermore, the model optimizes the rate to be charged from alternate sources during an outage. The proposed optimization enhances the financial viability of distribution licensees by 87.5% on average, along with maximizing the benefits to consumers by an average savings of 50%
A Novel Hierarchical Pipeline for Fine-Grained Punch Recognition in Uncontrolled Setting
No full textHuman Action Recognition (HAR) is one of the most emerging topics in the field of Computer Vision. It finds utilization in a wide range of applications like athletics, healthcare, security, sports performance, etc. In sports, HAR can be used to monitor athletes’ movements to facilitate skill development and decision-making training. However, in case of highly dynamic sports like boxing, automatic HAR becomes more difficult. Variations in lighting conditions, background, camera perspectives, and rapid movements collectively compound the complexity in automatic HAR and its performance further worsens with the involvement of uncontrolled environment videos. This manuscript proposes a hierarchical pipeline for robust sports activity recognition. For this purpose, a novel regression-based detection is introduced using a Dual Stream Spatio-Temporal Transformer, and a 3D Convolutional Neural Network (CNN) is used for fine-grained classification. The approach commences with regression-based detection to identify punch instances within unedited boxing video streams. Subsequently, a fine-grained classification module is employed to categorize detected punches into six basic punch types: jabs, cross, lead, and rear hooks, or lead and rear uppercuts. This hierarchical architecture enables efficient and accurate punch recognition in diverse real-world wild settings. Experimental results on various unedited YouTube videos show the effectiveness of our proposed approach. The proposed approach achieves an overall mean detection accuracy of 96.09% and a mean classification accuracy of 88.25% on test videos
Design of a NIR fluorescent chemosensor for the detection and imaging of hydrogen sulfide and cysteine in living cells and blood serum
No full textCysteine (Cys) and hydrogen sulfide (H2S) are biologically important thiols involved in cellular redox regulation, signaling, and disease progression. Herein, we report a novel near-infrared (NIR) fluorescent probe, DN-D, based on a naphthalene-modified BODIPY fluorophore conjugated with a 2,4-dinitrobenzenesulfonyl group, for the relatively selective and sensitive detection of Cys and H2S. The 2,4-dinitrobenzenesulfonyl group moiety acts as a thiol-responsive trigger, undergoing nucleophilic aromatic substitution upon interaction with Cys or H2S, thereby releasing the active fluorophore (DN - OH) and yielding a strong fluorescence signal at 695 nm (λex = 650). The probe exhibits a large Stokes shift (40 nm), excellent selectivity against other amino acids and biologically relevant analytes, and rapid response times, 2S and 15 min for Cys. Importantly, the probe enables highly sensitive detection with low limits of detection (LoD): 119 nM for Cys and 94 nM for H2S. DN-D performs reliably under physiological pH conditions (pH 6 - 8), shows low cytotoxicity, and strong stability. Its practical utility is validated by the successful detection of thiols in human blood serum (up to 70-fold dilution) and live HeLa cell imaging
Dynamics of convective clouds near and below the lifting condensation level over a semi-arid Western-Indian region
No full textDirectional oil retention and abrasion properties of microgrooved self-cleaning slippery surfaces for sanitation applications
No full textLubricant infused slippery surfaces are vulnerable to external shear flow of fluids (water, air). This study reports the influence of mimicked commode flushing turbulent (Re ∼ 6129) water flow on the silicone oil retention and feces self-cleaning properties in microgrooved polydimethylsiloxane replicas fabricated using banana leaf template. Oil retention amounts are 28 %, 42 %, and 24 % for 20 min of constant turbulent flow in parallel (∥), perpendicular (⊥) directions to grooves and on untextured surfaces, respectively. Post flow, water slide-off angles (SAs) are ∼ 9° for ⊥ flow, ∼14° for ∥ flow, showcasing the retention of slipperiness. On the other hand, untextured surfaces lost their slipperiness. Also, oil retention in air under 200 gliding water droplets shows trend of ⊥ to grooves > ∥ to grooves > untextured. Furthermore, oil coated microgrooves displayed smaller coefficient of friction of 0.35 ± 0.009 (⊥ to grooves), 0.38 ± 0.003 (∥ to grooves), as compared to untextured surfaces (1.73 ± 0.198), when abraded with a steel ball in reciprocating motion using 1 N load, 40 mm⋅s−1 sliding speed and 10 mm sliding distance. After 30 consecutive cycles of synthetic feces deposition, its residual amount is lowest when sliding on ∥ to grooves as compared to ⊥ to grooves and untextured surfaces. Clearly, a trade-off between ⊥ and ∥ directions to grooves can provide optimal oil retention and self-cleaning properties in sanitation and sewage systems
Autophagy induction in TNBC cells by 5,15-diazaporphyrins: synthesis, X-ray structure, ROS generation and photodynamic efficiencies
No full textA series of novel 5,15-diazaporphyrins having N-substitutions in place of C-5 and C-15 atoms were synthesized and characterized. The substitution of N-5 and N-15 atoms in the core led to highly planar diazaporphyrin ring and intense absorption band between 640 and 700 nm. All the diazaporphyrins exhibited strong fluorescence around 640 nm with 4–29 % emission quantum yields. The in-vitro photocytotoxicity studies of diazaporphyrins on triple-negative breast cancer cells revealed excellent autophagy activation. The homoleptic diazaporphyrin displayed excellent IC50 value (1.1 µM) in combination with chloroquine. The diazaporphyrins colocalized in the endoplasmic reticulum and caused stress in cancer cells. One of the diazaporphyrin acted as excellent autophagy inducer and enhanced the expression of autophagy marker proteins as established by western blot analysis. The autophagy inducing 5,15-diazaporphyrins are promising candidates as theragnostic agents for triple negative breast cancer