Judicious Exploitation Research Articles

Interfacial Reactions in Chemical Recycling and Upcycling of Plastics.

Depolymerization of plastics is a leading strategy to combat the escalating global plastic waste crisis through chemical recycling, upcycling, and remediation of micro-/nanoplastics. However, critical processes necessary for polymer chain scission, occurring at the polymer-catalyst or polymer-fluid interfaces, remain largely overlooked. Herein, we spotlight the importance of understanding these interfacial chemical processes as a critical necessity for optimizing kinetics and reactivity in plastics recycling and upcycling, controlling reaction outcomes, product distributions, as well as improving the environmental sustainability of these processes. Several examples are highlighted in heterogeneous processes such as hydrogenation over solid catalysts, reaction of plastics in immiscible media, and biocatalysis. Ultimately, judicious exploitation of interfacial reactivity has practical implications in developing practical, robust, and cost-effective processes to reduce plastic waste and enable a viable post-use circular plastics economy.

Model and performance analysis of energy conversion in functionally graded flexoelectric semiconductor nanostructures

Energy systems converting efficiently from surrounding environment for powering semiconductor electronic components at nanoscale has attracted intense research interests. Due to the strong size dependency, flexoelectricity has been demonstrated as an excellent candidate implemented as nanoscale piezoelectric semiconductor energy harvesters. In this work, through a judicious exploitation of structural symmetry and nonuniformity, we theoretically study the energy conversion behaviors of a novel asymmetric nanodisk model composed of functionally graded (FG) flexoelectric semiconductor (FS) (FG-FS) materials while being loaded with thickness-extensional mechanical vibration. In numerical analysis, the material parameters have been treated with a general variation method under the Cartesian coordinate systems for simplicity. Taking into accounts of the nonuniform structural form and multi-field coupling features, we derived an octic governing equation with variable coefficients for the current analyzed FG-FS nanodisk structure, which is, however, almost impossible to obtain analytical solutions. To successfully address this issue and also further explore the improved performance and new phenomena induced by the FG type of non-uniform structural profile, we specially proposed an efficient tensor algorithm and reduced the octic governing equation into one quartic equation with variable coefficients and other four common quadratic equations. Later, we explicitly explored the effect of each physical parameter on the energy conversion performance of the FS energy harvester by studying the variations of the output electric power density and the energy conversion efficiency. Results illustrated that the electromechanical energy conversion behaviors of the studied FG-FS nanodisk can be properly tuned by not only the related material parameters but also their gradations. We believe our work have the potential to pave new way for the designs and manufacture of novel nano-electronic semiconductor components for the future practical applications.

Optimizing spectrum efficiency in 6G multi-UAV networks through source correlation exploitation

In the context of 6G and 5G communication networks, particularly in disaster-stricken areas with a surging demand for connectivity and the rapid evolution of the internet of everything (IoE), the imperative for augmenting spectrum efficiency in unmanned aerial vehicles (UAVs) communication-enabled wireless networks becomes ever more pronounced. This work embarks on the mission of significantly enhancing spectrum efficiency by capitalizing on redundancies, such as correlations inherent in data sources like co-located video sensors. While the intuitive potential of exploiting redundancies for spectrum efficiency enhancement is apparent, our approach is systematically structured. We introduce a linear programming framework designed to meticulously allocate bandwidth to individual links based on their respective demands, while judiciously adhering to spatial spectrum reuse constraints. Subsequently, we employ this linear program to empirically quantify the improvements in spectrum efficiency engendered by source correlations. Furthermore, we elucidate various strategies for harnessing these correlations to maximize spectrum efficiency gains, while navigating the trade-off terrain between computational complexity and precision. Our findings resoundingly underscore the trans-formative power of identifying the precise set of source correlations, resulting in spectrum efficiency enhancements of up to two orders of magnitude. In terms of network performance, the judicious exploitation of source correlations grants admission to nearly 100% of delay-intolerant traffic, alongside substantial reductions in mean delay for delay-tolerant traffic.”

Optimizing Forest-Biomass-Distribution Logistics from a Multi-Level Perspective—Review

Forest and wood biomass represent a sustainable reservoir of raw materials and energy, offering a viable alternative to fossil fuels. These resources find extensive use in producing bioproducts, including solid wood and wood materials. The judicious exploitation of forest and wood biomass can be pivotal in reducing carbon emissions and securing material and energy independence. The business viability of producing valuable goods from woody biomass hinges on ensuring its sustained availability. This necessitates access to high-quality biomass at a minimal cost, demanding the efficient design of wood-biomass-distribution logistics. Furthermore, it is imperative to give equal weight to social and ecological considerations in shaping the forest- and wood-biomass-distribution logistics, thereby ensuring the sustainable utilization of this renewable raw material source. This article presents research focused on the business optimization of distribution logistics for specific forms of forest biomass used in wood material production. While most studies have primarily concentrated on the business or ecological issues of biomass utilization, this article offers a comprehensive insight by addressing business, ecological, and social facets in assessing and optimizing wood-biomass-distribution logistics. Multi-stakeholder life-cycle-assessment optimization takes into account the reduction of greenhouse gases as an ecological metric, with production costs and capital expenditure forming the business metrics. At the same time, the generation of employment opportunities is commonly regarded as the pivotal social criterion. There remains a necessity for further exploration into the potential social impacts of forest biomass utilization. Additionally, developing enhanced methodologies and decision-support tools for scheduling wood-biomass-distribution logistics that holistically consider business, ecological, and social criteria is an essential ongoing task.

Natural grid stretching for DNS of compressible wall-bounded flows

We propose a physics-driven stretching function for direct numerical simulation (DNS) of compressible turbulent wall-bounded flows, which blends uniform near-wall spacing with uniform resolution in terms of semi-local Kolmogorov units in the outer wall layer. Given target Mach number, Reynolds number and wall temperature, our procedure yields a well-defined prescription for the number of grid points and their distribution which guarantee at the same time numerical accuracy and judicious exploitation of computational resources. DNS of high-speed turbulent boundary layers are used to evaluate the quality of the proposed stretching function, which show that one can achieve identical results as with general-purpose stretching functions, however with substantially higher efficiency. A Python script is provided to facilitate implementation of the proposed grid stretching.

λ3 - and λ5 -Iodanes: Substituent Effects and Pseudorotation/Hypervalent Twisting.

Hypervalent iodine (III and V) compounds exhibit positional isomerization through pseudorotation or twisting; the latter have been invoked for the stability as well as the reactivity of λ3 - and λ5 -iodanes. By judicious exploitation of sterics, the twisting process in iodanes can be facilitated to promote reactivity. For example, ortho-substitution in λ3 - and λ5 -iodanes accelerates α-tosyloxylation of ketones and oxidation of alcohols. The enhancement of reactivity arises from sterically-induced non-planarity and the resultant weakening of the 3c-4e bonds involving the hypervalent iodine atom. The ortho-substitution constitutes an important strategy to maneuver reactivity, control selectivity, and develop new catalysts, including chiral, for diverse reactions. This review entails coverage of the literature developments in regard to the effect of substituents and twisting/pseudorotation on the stability as well as the reactivity of hypervalent λ3 - and λ5 -iodanes, and the application of the latter for synthetic transformations.

Emergent quasi-two-dimensional metallic state derived from the Mott-insulator framework

Recent quasi-two-dimensional (quasi-2D) systems with judicious exploitation of the atomic monolayer or few-layer architecture exhibit unprecedented physical properties that challenge the conventional wisdom on condensed matter physics. Here we show that the infinite layer ${\mathrm{SrCuO}}_{2}$ (SCO), a topical cuprate Mott insulator in bulk form, can manifest an unexpected metallic state in the quasi-2D limit when SCO is grown on ${\mathrm{TiO}}_{2}$-terminated ${\mathrm{SrTiO}}_{3}$ (STO) substrates. The sheet resistance does not conform to Landau's Fermi liquid paradigm. Hard x-ray core-level photoemission spectra demonstrate a definitive Fermi level that resembles the hole doped metal. Soft x-ray absorption spectroscopy also reveals features analogous to those of a hole doped Mott insulator. Based on these results, we conclude that the hole doping does not occur at the interfaces between SCO and STO; instead, it comes from the transient layers between the chain-type and the planar-type structures within the SCO slab. The present work reveals a metallic state in the infinite layer SCO and invites further examination to elucidate the spatial extent of this state.

Harmonic generation from silicon membranes at visible and ultraviolet wavelengths.

Nonlinear silicon photonics offers unique abilities to generate, manipulate and detect optical signals in nano-devices, with applications based on field localization and large third order nonlinearity. However, at the nanoscale, inefficient nonlinear processes, absorption, and the lack of realistic models limit the nano-engineering of silicon. Here we report measurements of second and third harmonic generation from undoped silicon membranes. Using experimental results and simulations we identify the effective mass of valence electrons, which determines second harmonic generation efficiency, and oscillator parameters that control third order processes. We can then accurately predict the nonlinear optical properties of complex structures, without introducing and artificially separating the effective χ(2) into surface and volume contributions, and by simultaneously including effects of linear and nonlinear dispersions. Our results suggest that judicious exploitation of the nonlinear dispersion of ordinary semiconductors can provide reasonable nonlinear efficiencies and transformational device physics well into the UV range.

Tuning nanoscale plasmon-exciton coupling via chemical interface damping.

Understanding the exact role of each plasmon decay channel in the plasmon-exciton interaction is essential for realizing the translational potential of nanoscale plexciton hybrids. Here, using single-particle spectroscopy, we demonstrate how a particular decay channel, chemical interface damping (CID), influences the nanoscale plasmon-exciton coupling. We investigate the interaction between cyanine dye J-aggregates and gold nanorods in the presence and absence of CID. The CID effect is introduced via surface modification of the nanorods with 4-nitrothiophenol. The relative contribution of CID is systematically tuned by varying the diameter of the nanorods, while maintaining the aspect ratio constant. We show that the incorporation of the CID channel, in addition to other plasmon decay channels, reduces the plasmon-exciton coupling strength. Nanorods' diameter-dependency measurements reveal that in the absence of CID contribution, the plasmon mode-volume factor gradually dominates over the plasmon decoherence effects as the diameter of the nanorods decreases, resulting in an increase in the plasmon-exciton coupling strength. However, the situation is entirely different when the CID channel is active: plasmon dephasing determines the plasmon-exciton coupling strength by outweighing the influence of even a very small plasmon mode-volume. Most importantly, our findings indicate that CID can be used to controllably tune the plasmon-exciton coupling strength for a given plexciton system by modifying the nanoparticle's surface with suitable adsorbates without the need for altering either the plasmonic or excitonic systems. Thus, judicious exploitation of CID can be tremendously beneficial in tailoring the optical characteristics of plexciton hybrid systems to suit any targeted application.

TinoTranscriptDB: A Database of Transcripts and Microsatellite Markers of Tinospora cordifolia, an Important Medicinal Plant.

Tinospora cordifolia, commonly known as “Giloe” in India, is a shrub belonging to the family Menispermaceae. It is an important medicinal plant known for its antipyretic, anti-inflammatory, antispasmodic, and antidiabetic properties and is used in the treatment of jaundice, gout, and rheumatism. Despite its economic importance, the limited information related to its genomic resources prohibits its judicious exploitation through molecular breeding or biotechnological approaches. In this study, we generated a meta-transcriptome assembly of 43,090 non-redundant transcripts by merging the RNASeq data obtained from Roche 454 GS-FLX, and Illumina platforms, and report the first transcriptome-based database for simple sequence repeats and transcription factors (“TinoTranscriptDB” (Tinospora cordifolia Transcriptome Database)). We annotated 26,716 (62%) of the total transcripts successfully from National Center for Biotechnology Information non-redundant protein (NCBI-NR), gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Swiss-Prot, and Pfam databases. This database contains information of 2620 perfect simple sequence repeats (P-SSRs) with a relative abundance of 340.12 (loci/Mb), and relative density of 6309.29 (bp/Mb). Excluding mono-nucleotides, the most abundant SSR motifs were tri-nucleotides (54.31%), followed by di-nucleotides (37.51%), tetra-nucleotides (4.54%), penta-nucleotides (3.16%) and hexa-nucleotides (0.45%). Additionally, we also identified 4,311 transcription factors (TFs) and categorized them into 55 sub-families. This database is expected to fill the gap in genomic resource availability in T. cordifolia and thus accelerate molecular breeding and related functional and other applied studies aimed towards genetic improvements of T. cordifolia and related species.

THE ANALYTIC T-MATRIX FOR THE HULTHÉN POTENTIAL IN ALL PARTIAL WAVES

Analytical expression for the Hulthén off-shell T -matrix in all partial waves is constructed in its maximal reduced form. As a basic requirement the off-shell solutions and Jost function are first developed by following the differential equation approach to the problem together with judicious exploitation of the properties of certain special functions of mathematical physics . The off-shell T -matrix is found to be in order with respect to its limiting behaviours and off-shell unitarity.

Retrieving Linear and Nonlinear Optical Dispersions of Matter: Combined Experiment-Numerical Ellipsometry in Silicon, Gold and Indium Tin Oxide

The predominant methods currently used to determine nonlinear optical constants like the nonlinear refractive index n2 or the third order susceptibility χ(3) rely mostly on experimental, open and closed z-scan techniques and beam deflection methods. While these methods work well when the linear absorption is relatively small or negligible, the retrieval process is more complicated for a strongly scattering, dispersive or absorbing medium. The study of optics at the nanoscale in the picosecond or femtosecond laser pulsed regimes demands the development of new theoretical tools, and diverse experimental approaches, to extract and verify both linear and nonlinear optical dispersions exhibited by matter, especially when material constituents are fashioned into nanostructures of arbitrary shape. We present a practical, combined experimental and theoretical approach based on the hydrodynamic model that uses experimental results of harmonic generation conversion efficiencies to retrieve complex, nonlinear dispersion curves, not necessarily only for third order processes. We provide examples for materials that are of special interest to nanophotonics, for example, silicon, gold, and indium tin oxide (ITO), which displays nonlocal effects and a zero-crossing of the real part of the dielectric constant. The results for silicon and gold compare well with analytical predictions of nonlinear dispersion based on the nonlinear oscillator model. Based on our assessment of third harmonic generation conversion efficiencies in silicon, we predict χω(3) and χ3ω(3) are of order 10−17 (m/V)2 in the visible and near IR ranges, with respective peaks of 10−14 (m/V)2 and 10−16 (m/V)2 in the UV range. Similarly, gold’s χω(3) and χ3ω(3) are of order 10−17–10−16 (m/V)2, and predict χω(3)∼10−17(m/V)2 and χ3ω(3)∼10−18(m/V)2 for ITO. These results clearly suggest that judicious exploitation of the nonlinear dispersion of ordinary semiconductors has the potential to transform device physics in spectral regions that extend well into the UV range.

Fishery and biological traits of obtuse barracuda Sphyraena obtusata (Cuvier, 1829) off south-west coast of India

Aim: The present study was conducted to investigate the fishery, diet composition and reproductive aspects of obtuse barracuda landed in Karnataka, south-west coast of India. Methodology: Feeding and reproductive traits of 1229 samples (638 males and 591 females) of S. obtusata was studied for a period of five years. The index of relative importance (IRI) was determined for each diet component in the stomach. Reproductive aspects such as maturity stages, gonadosomatic index and fecundity were investigated. Results: The most predominant prey item in terms of frequency of occurrence (93.1%), number (91.4%), weight (93.2%), IRI (3615.5) and also % IRI (98.5%) was fishes. Crustaceans and cephalopods were noticed less frequently and were represented by shrimps and Loligo sp. The estimated length at first maturity for male and female fishes was 20.5 and 21.3 cm, respectively. Higher GSI values were observed during post monsoon (October-November) followed by summer pre monsoon (April-May) season in both males and females, indicating two peak spawning periods. Interpretation: The comprehensive study on major biological characteristics of Sphyraena obtusata could be useful for developing appropriate management strategies for conservation and judicious exploitation of this commercially important resource. Key words: Barracuda, Fecundity, Gonadosomatic index, Sphyraena obtusata

An empirical study on the underutilized medicinal genus Kaempferia from India revealed cytological and genetic variability

The genus Kaempferia L., consisting of aromatic and ornamental species found in east and south-east Asia, have profound ethno-medicinal usages as antimicrobial and anticancer agents, attributable to presence of novel cyclohexane derivatives, flavonoids and di-terpenes. Represented by only 7 species in India, a comprehensive genetic study of Kaempferia from the country is lacking. We present here a study of 4 species of this genus from India, namely, K. rotunda, K. galanga, K. elegans and K. angustifolia. Cytological analyses revealed distinct inter-specific ploidy and consequent somatic chromosome number variations (2n = 22 to 2n = 54). High inter- and intra-chromosomal variability was observed with chromosome lengths ranging from 0.87 to 6.63 µm, constriction types varying from median to sub-median range and different secondary constrictions, along with contrasting values of asymmetry indices. RAPD and ISSR analyses of 8 accessions produced 1,398 polymorphic bands, their sizes ranging from 100 to 2000 bp; percentage polymorphism varying from 84 to 100%. UPGMA dendrogram generated using the polymorphic fragments showed Jaccard's similarity coefficient value varying between 0.07 and 0.93, producing 3 separate clusters for the studied Kaempferia species. ITS, matK and rbcL loci sequence analyses also confirmed high level of inter-specific variability of Kaempferia. Genetic variation revealed in this study could indicate chemotypic differences in Kaempferia and will direct our future research for a wider cytogenetic and phytochemical investigation including all the Indian species that would open up avenues for judicious exploitation of these medicinally important plants.

Seasonal abundance and diversity of finfish in a tropical estuary, Karwar, southwest coast of India

The spatial and seasonal variability in finfish availability in the tropical Kali Estuary, in Karwar was studied from January 2017- May 2019 at three stations. A total of 26 species belonging to 9 orders and 20 families were recorded from the Kali Estuary and the order Perciformes with 16 species dominated the group (62%) followed by order Mugilliformes and Pleuronectiformes (8%). Maximum abundance was observed during the pre-monsoon season in all the stations. Excluding Ambassis ambassis which was abundant in all the stations, Caranx ignobilis dominated in all the stations. Truly marine and estuarine species of fishes recorded dominated than the freshwater estuarine ones like Etroplus suratensis, Scatophagus argus, Aplocheilus lineatus. Number of species recorded at each station during the study ranged from 11 to 25 and it was significantly different between stations. The Shannon- Wiener diversity index ranged from 2.0 to 4.6, the minimum in station 1 and maximum in station 3. The seasonal analysis of diversity also showed minimum value during the monsoon season in station 1 and maximum value in station 3. The minimum value (2.2) of Margalef richness index was also recorded in Station 1 during monsoon season and maximum value (4.2) in Station 2. When comparing the relative abundance using Pielou’s evenness index (J’) the values were in the range of 0.92 to 0.99 which was closer to one, indicating evenness in distribution. There was similarity in species composition according to different seasons except for monsoon season in Station 1. The same pattern was also evident in the MDS plot where seasonal aggregation was observed between the stations. In addition to the diversity studies, the surveys also threw light on the abundance and seasonality of candidate species suitable for mariculture like C. ignobilis, Lutjanus spp., Etroplus spp., etc. Judicious exploitation of the species could help brackishwater fish farmers.

Reproductive biology of the sawtooth barracuda, Sphyraena putnamae (Jordan and Seale, 1905) along the coastal waters of Karnataka, southeastern Arabian Sea

The reproductive cycle, maturity, sex ratio, and fecundity of the sawtooth barracuda Sphyraena putnamae was investigated from 1108 specimen samples along the Karnataka coast off the southeastern Arabian Sea. The sex ratio between males and females (1:1.08) was not significantly different. The fork length at 50% maturity (Lm50) for females and males was estimated at 39.4 cm and 38.0 cm, respectively. The pattern of Gonadosomatic index (GSI) and the maturity stages of females suggest two peaks in the spawning, with a distinct one during April–May and a less prominent one between November–January.​ However, the incidence of spawning capable, regressing and regenerating fishes all through the year in varied frequencies implies that spawning takes place throughout the year. The absolute fecundity estimates vary from 69,689 eggs for a female of 30.4 cm fork length (FL) to 944,793 eggs for a female of 73 cm FL. The average batch fecundity was calculated as 310,763 hydrated oocytes per female. The relative batch fecundity ranges from (female gutted weight) 285 to 964 eggs g−1 with an average of 605 eggs g−1. Fecundity correlates positively with fish length and weight indicating that larger females produce a greater number of eggs compared with the smaller ones. The biological information on maturation, reproductive cycle, spawning periodicity and potential provided for the first time in this study can be useful for developing appropriate management strategies for the conservation and judicious exploitation of this commercially important barracuda species.

Amino Acids and Peptides as Functional Components in Arylenediimide-Based Molecular Architectonics

Abstract Molecular architectonics has its essence in custom design and engineering of molecular assemblies by judicious exploitation of the noncovalent forces to construct ordered architectures with novel properties and functions. The art of mastering the programmed molecular assemblies is a challenging task owing to complex factors that govern recognition events at the molecular level. In this context, biomolecules with in-built information for molecular recognition are capable of guiding the molecular architectonics to construct nano, micro, and macro-architectures with functional properties and applications. In particular, amino acids and peptides are attractive auxiliaries to guide the controlled molecular self-assembly, coassembly, heterostructures and living assembly systems of functional molecules in the scheme of molecular architectonics. Use of these exquisite biomolecular auxiliaries to master the art of engineering the molecular assembly of functional aromatic units viz., arylenediimides has been a continuous effort in the emerging field of molecular architectonics. In this accounts article, we outline the amino acid and peptide functionalized arylenediimide-based designer molecular systems as functional modular units developed by our group and others with an objective to demonstrate the concept of molecular architectonics to construct functional nano, micro and macroarchitectures with wide range of properties and applications.

Off-shell Jost function for the Hulthén potential in all partial waves

A new expression for the Hulthén off-shell Jost function in all partial waves is constructed in its maximal reduced form. As a basic requirement the on-shell solutions are first developed by following the differential equation approach to the problem together with judicious exploitation of the properties of certain special functions of mathematical physics. Utilizing the properties of the Jost function, the binding energies and phase shifts for N-N and n-d systems are computed and found excellent agreement with standard data.

Non-marginal decisions: A novel Bayesian multiple testing procedure

In this paper, we consider the problem of multiple testing where the hypotheses are dependent. In most of the existing literature, either Bayesian or non-Bayesian, the decision rules mainly focus on the validity of the test procedure rather than actually utilizing the dependency to increase efficiency. Moreover, the decisions regarding different hypotheses are marginal in the sense that they do not depend upon each other directly. However, in realistic situations, the hypotheses are usually dependent, and hence it is desirable that the decisions regarding the dependent hypotheses are taken jointly. In this article, we develop a novel Bayesian multiple testing procedure that coherently takes this requirement into consideration. Our method, which is based on new notions of error and non-error terms, substantially enhances efficiency by judicious exploitation of the dependence structure among the hypotheses. We show that our method minimizes the posterior expected loss associated with an additive “0-1” loss function; we also prove theoretical results on the relevant error probabilities, establishing the coherence and usefulness of our method. The optimal decision configuration is not available in closed form and we propose an efficient simulated annealing algorithm for the purpose of optimization, which is also generically applicable to binary optimization problems. Extensive simulation studies indicate that in dependent situations, our method performs significantly better than some existing popular conventional multiple testing methods, in terms of accuracy and power control. Moreover, application of our ideas to a real, spatial data set associated with radionuclide concentration in Rongelap islands yielded insightful results.

Multi-cluster analysis of Crabs and Ichthyofaunal Diversity in relation to habitat distribution at Tropical Mangrove ecosystem of the Indian Sundarbans

Mangroves have enormous ecological significance and socio-economic importance as promising hub for tropical marine and estuarine biotope. Therefore, mangroves are considered one of the world’s richest resources of biological and genetic diversity. Although, crabs and fishes significantly occur among the other macrofauna of the Sundarbans mangrove ecosystem, supportive information on resource and diversity of mangrove’s macrofauna are insufficient due to their non judicious exploitation in unscientific ways. Concerning that, the present survey based experimental research find out the localized endemic composition and bio-distribution of crabs and estuarine fish species which are prevalent in the tropical Sundarbans mangrove systems. A special drive has also been taken to characterize the variation of such species in course of spatial and environmental changing scenario. The consequences of this research concluded a total 115 numbers of crab species and 312 numbers of brackish and marine water fish species were available at Sundarbans. Which are identified, categorically assessed showing their predominant positions in the localized mangrove-associated estuary of 17 different specified clusters or survey areas. Apart from that, the Multivariate Cluster Analysis was performed on the available fish and crab diversity, up to the Family and Species level following their present conservation status.