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This paper focusses on developing two species, where only prey species suffers by a contagious disease. We consider the logistic growth rate of the prey population. The interaction between susceptible prey and infected prey with predator is presumed to be ruled by Holling type II and I functional response, respectively. A healthy prey is infected when it comes in direct contact with infected prey, and we also assume that predator-dependent disease spreads within the system. This research reveals that the transmission of this predator-dependent disease can have critical repercussions for the shaping of prey–predator interactions. The solution of the model is examined in relation to survival, uniqueness and boundedness. The positivity, feasibility and the stability conditions of the fixed points of the system are analysed by applying the linearization method and the Jacobian matrix method.

This paper describes novel soft dielectric elastomer composites that exhibits interesting features from the perspective of dielectric-elastomer transducer development, with enhanced actuation performance under an applied electric field that are potentially suitable for actuator applications. Materials solutions described are a combination of ceramic BN platelets, used at low loading levels, and a plasticizer (Naphthenic Oil) in a polymer matrix and synergistic effects between them that leads to enhancement in actuation strain by as high as 328% under applied electric field. Such functional dielectric composites would alleviate several issues such as size, functionality, and performance for many real-world actuator applications.

For batteries, thicker electrodes increase energy density, however, molecular transport limits the rate of charge/discharge for extracting large fractions of available energy. Mitigating transport limitations by increasing electrolyte conductivity and aligning the pores in the electrode microstructure are described.

The central focus of this study is to investigate the influence of microstructure and direction of impact (relative to the growth direction of ice crystals) on the impact behavior of ice-templated sintered alumina materials and understand the relationship between dynamic compressive strength and impact response. All materials were fabricated using alumina suspensions of the same solid loading but at three different freezing front velocity (FFV) regimes; very-high FFV, moderately-high FFV, and low FFV. Lamella wall thickness, pore size, and pore aspect ratio decreased, and wall connectivity increased with FFV. Materials also exhibited a structural gradient along the growth direction of ice crystals. As the templated microstructure became finer with FFV, the impact resistance of the materials increased, and radius of damage crater, depth-of-penetration, and mass loss decreased. Materials also exhibited radial cracking, and the materials fabricated at very-high FFV showed a greater propensity for radial cracking for impact along the growth direction. The impact process evolved in three phases; penetration phase, dwell phase and rebound phase. Analysis of high-speed videos revealed that modifying the microstructure affected not only the impact resistance but also the duration of these phases. Variation in microstructure caused a change in the mechanism of damage evolution during impact. Dynamic compressive strength increased with FFV, and the results revealed a direct relationship between impact response and strength. For both impact and dynamic compression, energy absorption per unit volume increased with FFV, further reinforcing the relationship between impact behavior and the dynamic compressive response of ice-templated materials.

NiO-TiO2 (TN) nanocomposite is synthesized from an assembly of p-type nickel oxide (NiO) and n-type titanium oxide (TiO2) in an ultrasound assisted operation. Transmission electron microscopy (TEM) demonstrates the existence of hexagonal particles in the nanocomposite. Dynamic light scattering (DLS) measurements show stable TN nanoparticles (NPs) at a negative zeta potential (−18.5 ± 0.8 mV). The nanocomposite is tested for its catalytic activity towards degrading malachite green (MG), a known water toxicant and methylene blue (MB) under ultraviolet (UV) irradiation. Response surface methodology (RSM) is employed to optimise the influence of significant variables such as initial dye concentration, catalyst dose and time. Their mutual interactions are mapped by response surface and contour plots and correlated with degradation process by a designed model. The best photocatalytic efficiency (87%) is observed at an optimised concentration of 5 ppm dye with 10 ppm catalyst. The presence of inorganic ions and organic matter hardly affected the aggregate size of TN but caused a decline in photoactivity. The catalyst is found effective even in real water system (Hooghly River). A (Fluorine doped tin oxide) FTO/TN/Al heterojunction is fabricated. TN showed enhanced carrier mobility (1.03.10−4 m2V-1s-1) and low transit time (1.76.10-6 s) evaluated using space charge limited current (SCLC) theory. The nanocomposite appears suitable for energy preservation and environmental applications.

The role of metal salts in inducing supramolecular gel network formation was analysed by reacting two pyridyl-N-oxide amides with various diamagnetic zinc(II) and cadmium(II) salts. Metal induced s...

The control and prediction of the self-assembly process in multicomponent supramolecular gels are challenging because the structure and properties rely mostly on the geometry and spatial arrangemen...

The current study investigated the effects of porosity, microstructure, and strain rate regime on the damage evolution and failure behavior under uniaxial compressive loading conditions in ice-templated alumina materials. The compressive response was investigated in dynamic and quasistatic loading regimes. Microstructural analysis revealed that in the high porosity regime, morphology was lamellar. In the lower porosity materials processed at higher freezing front velocities (FFVs), morphology was dendritic but transitioned to lamellar structure with the decreasing FFV. Ice-templated materials with higher porosity exhibited progressive crushing type damage evolution, irrespective of the FFV and strain rate regime. The origin of progressive crushing type failure was observed to be the absence of macroscopic crack evolution in the vicinity of peak stress, and subsequent to peak stress damage evolved only in the form of minimal fragmentation that gradually increased with the increasing strain. However, at comparable strain, the extent of dynamic damage was less compared to quasistatic damage, which suggests enhanced resistance to brittle fracture at high-strain rates. With the decreasing porosity damage evolution process changed, particularly under quasistatic loading in the materials processed at higher FFVs. Up to peak stress materials were intact, whereas upon reaching peak stress significant damage evolved causing complete loss of compressive load-bearing capacity. Whereas, damage evolution under dynamic loading in the vicinity of peak stress was significantly limited and damage accumulated progressively with the increasing strain, which strongly suggests greater structural stability in the ice-templated porous ceramic materials at high-strain rates.

The combination of strong coordination bonds and hydrogen bonding interactions were used to generate a series of supramolecular coordination materials (SCMs), which was achieved by reacting a bis-pyridyl amide ligand, namely N-(4-pyridyl)nicotinamide (4PNA) with copper(II), zinc(II), and cadmium(II) benzoates. The SCMs were structurally characterized using X-ray diffraction and the key intermolecular interactions were identified via Hirshfeld surface analysis. The role of solvent molecules on the supramolecular architecture was analyzed by synthesizing the SCMs in different solvents/solvent mixtures. A solvent-mediated solid-state structural transformation was observed in copper(II) SCMs and we were able to isolate the intermediate form of the crystal-to-crystal transformation process. The luminescence experiments revealed that complexation enhanced the fluorescence properties of 4PNA in the zinc(II) and cadmium(II) SCMs, but a reverse phenomenon was observed in the copper(II) SCMs. This work demonstrated the tuning of supramolecular assembly in coordination compounds as a function of solvents for generating SCMs with diverse properties.

We investigated the effects of platelets and strain rate on the compressive response of ice-templated porous alumina, processed from ultrafine, equiaxed particles and from a mixture of ultrafine, equiaxed and large platelet particles. Results revealed a remarkable enhancement of the quasistatic and dynamic compressive mechanical properties of the templated ceramics in the presence of platelets. Specific compressive mechanical properties of the ice-templated alumina containing platelets are superior in comparison to those of the various metallic, syntactic and natural cellular solids. In the presence of platelets, compressive strength exhibited contrasting strain rate sensitivity between the elastic and inelastic stages of deformation.

We investigated and thoroughly analyzed compressive response of ice-templated ceramics in quasistatic and dynamic regimes of strain rate. In the high pore volume regime, sintered scaffolds exhibited highly lamellar pore morphology and pore architecture transitioned to dendritic with the decreasing pore volume. Mechanical property measurements in the quasistatic regime of strain rate revealed that with increasing density, compressive response transitioned from a damageable, cellular-like failure to a brittle-like failure. We rationalized the measured results in terms of the propensity of the lamella walls to undergo buckling. Our conjecture is that in the high pore volume regime, lamella walls of the scaffolds are prone to buckling-induced elastic instability, which leads to a compressive response that manifests a gradual decrease of stress beyond peak stress. In contrast, we suggest that in the low pore volume regime thick lamella walls and extensive transverse bridging exhibit marked resistance to buckling-induced instability and scaffolds undergo a global failure, which is manifested in the measured quasistatic compressive response as a sharp drop of stress beyond peak stress. Dynamic compressive response of the scaffolds exhibited measurable differences relative to the quasistatic compressive response. Scaffolds exhibited a relatively gradual decrease of dynamic compressive stress beyond peak stress, and an overall improvement of compressive response and energy absorption capacity was measured under the dynamic loading conditions. We rationalized the measured differences in between the strain rate regimes in terms of the micro-inertia and other effects. This study is of critical significance for applications of ice-templated structures in dynamic environments.

Following the internationalisation of food production and manufacturing, a significant increase of food fraud was discovered, ranging from false label claims to the use of additives and fillers to increase profitability. The accidental or fraudulent mixing of animal products or by-products from different species is an important preoccupation for consumers with health or ethical concerns. Gelatin is widely used during food processing as well as in cosmetics, nutraceutics and medical formulations. It contains mainly type I, II and III collagen polypeptides. Gelatin speciation was performed using a well-defined proteogenomic annotation, carefully chosen surrogate tryptic peptides and analysis using a hybrid quadrupole-Orbitrap MS. Gelatin samples were dissolved in ammonium bicarbonate buffer and proteins were digested with trypsin. The samples were analysed using high-resolution MS. Chromatography was achieved using a 30-min linear gradient on a Thermo BioBasic C8 100 × 1 mm column at a flow rate of 75 μL min

We attempted to develop a phenomenological understanding of the evolution of the fracture events within fine-grained lamella walls of partially deformed ice-templated sintered Al 2 O 3 scaffolds and revealed the effects of the platelets on the crack propagation characteristics. Detailed microstructural analyses suggest that intergranular cracks within the walls evolved at two orientations, parallel and perpendicular to the loading direction. We proposed probable mechanisms including one based on the so-called wing-crack model to rationalize the observed crack orientations. We presented crack propagation behavior in lamella walls in presence of the platelets and discussed the effects in terms of the crack deflection mechanism.

Background: Oxbow lakes are abundant in indigenous fishes, but they are subject to unsustainable fishing practices, potential overexploitation, and indiscriminate use of fine-meshed fishing gear. To quantify the catch per unit effort (CPUE) and impact of fishing gears on fish abundance, a survey was carried out in an oxbow lake in eastern India. Methods: The gear-wise CPUE for fish caught in per unit hour of operation was calculated by dividing the total sampling gear catch in biomass, which is the observed value of fish caught by a particular gear, by the total sampling effort hours. A value of P < 0.05 was accepted as statistical significance. Results: Average annual values of the CPUE of triangular push nets, gill nets, long lines, seine nets, drag nets, stationary dip nets, cone-framed cast nets, and line and hook were calculated as 328.34, 4.12, 36.71, 572.92, 3928.57, 237.78, 235.80, and 0.44 grams of fish per hour of operation, respectively. All the 8 different gears exhibited lower CPUE during monsoon and post-monsoon seasons than in the premonsoon season. The line and hook was dominant (>71%). Cone-framed cast net hauled the maximum catch in biomass (31.51%), and gill nets contributed the maximum number of fish (64.92%). The lower CPUE values of line and hook, gill net, cone-framed cast net and long lines identified them as the most harmful among all gears. Conclusion: Indiscriminate use of gear, particularly line and hook, gill nets, cone-framed cast nets, and long lines, demands regulations and preventions concerning such gear to obtain higher fish abundance.

This paper describes nonlinear dielectric composite passive components on flexible metallic substrates for transient protection of electronic devices, most notably against electrostatic discharge (ESD) and electrical overstress (EOS) conditions. In this case, the passive device comprises a polymer composite that contains nonlinear inorganic fillers, an electric field switchable dielectric ceramic Calcium Copper Titanate (CaCu3Ti4O12, CCT), in a metal insulator metal (MIM) configuration. Compatibility with PCB (printed circuit board) in line processing is demonstrated since the fabrication process described is a relatively low temperature process. Advantageously, the construction of such components are such that they can be embedded within a PCB (printed circuit board), thereby allowing miniaturization of the circuit design and can potentially be adopted in an industrial roll to roll manufacturing process. The dielectric characteristics of the CCT filler polymer composites are compared with well-known high dielectric constant Barium Titanate filler polymer composites for capacitor applications. Theoretical models based on effective medium theory are used to predict the dielectric properties of the CCT epoxy composites as a function of filler loading fractions. Maxwell Garnett model was found to provide the best fit to experimental data.

Ice-templated ceramics have unique lamellar pore morphology that offers better compressive mechanical properties in comparison to the typical ceramic foams with isotropic pore morphology. However, for very high-level porosity (>65 vol%) strength difference diminishes. This investigation reveals that by inducing anisotropic grains within the matrix of a fine-grained ceramic, uniaxial compressive response of the ice-templated sintered scaffolds can be markedly enhanced without causing any considerable modification of the total porosity. To address this innovative materials design strategy, we synthesized a series of microstructures by systematically varying the anisotropic grains content in an aqueous suspension and the freezing kinetics to investigate the process-microstructure correlations and understand the structure-property relationships. Microstructural investigations revealed the unique arrangements of the platelets within and out of the lamella walls, where the upward moving ice fronts aligned the platelets' in-plane direction to the ice-growth direction. In the low freezing front velocity regime, platelets were observed to be mainly within the lamella walls, whereas platelets started to develop lamellar bridges with the increasing velocity. As a result, a transition of the pore morphology occurred with the increasing platelets content and the freezing front velocity. A novel method based on the rigorous microstructural analysis is developed to estimate the distribution of the platelets within and out of the walls and the variation of the platelets distribution with the composition and freezing front velocity. A drastic improvement of the compressive mechanical properties (stiffness, strength, energy absorption capacity) was measured due to the platelets' addition, which has been related to the platelets' distribution within and out of the walls and the pore morphology modifications. Results are rationalized based on the role of the platelets during the compressive deformation.

This paper describes the effects of the grain-level anisotropy on the microstructure and uniaxial compressive response of the ice-templated alumina scaffolds. Highly porous (~ 80 vol.%) scaffolds were fabricated from alumina powders of equiaxed morphology as well as from powder mixtures containing equiaxed and small amount of platelet particles. Presence of the platelets (diameter 8 μm and thickness 400 nm) led to the formation of the interlamellae bridges, and significantly enhanced the stiffness and compressive strength of the scaffolds. Measured improvement of the mechanical response is rationalized based on the stiffening and strengthening effects exhibited by the intralamella and interlamella platelets.

The present work deals with the compensation of third-order dispersion (TOD) in view of parabolic pulse (PP) generation in standard normal dispersion-decreasing fiber (NDDF) links by using phase modulator (PM) at certain position within the link. Since the inherent TOD in the fiber leads to an asymmetric pulse shape and thus degrades the PP formation, there is a strong requirement to minimize the TOD within the fiber link. It is seen that insertion of PM at the estimated critical length reduces misfit parameter satisfactorily at the output end and an equivalent PP is regenerated. A three-stage cascaded system comprising the first section of NDDF, dispersion-shifted fiber (DSF) and a normal dispersion fiber (NDF) may also be useful to mitigate TOD by showing the equivalent performance as that obtained by employing PM in the previous case.

We report the crystallisation of three forms of the copper(II) isonicotinate–N-oxide complex and their phase interconversion via solvent-mediated crystal-to-crystal transformation. The different forms of the copper complex have been isolated and characterised by single crystal X-ray diffraction. Gel phase crystallisation performed in hydrogels, low molecular weight gels and gels of a tailored gelator showed crystal habit modification. Crystallisation in aqueous ethanol resulted in the concomitant formation of blue (form-I) and green (form-II/IV) crystals while the use of a low molecular weight gel resulted in the selective crystallization of the blue form-I under identical conditions. Comparison of the gel phase and the solution state crystallisation in various solvent compositions reveals that the blue form-I is the thermodynamically stable form under ambient conditions.

The ice-templating technique enables the fabrication of multilayered ceramic-based composite materials. Very little is known on the inelastic deformation mechanisms that evolve in this class of composite materials under compressive loading conditions and cause macroscopic failure. The current investigation is motivated by a recent study by the authors, which revealed that the uniaxial compressive response of ice-templated ceramic–polymer composites is strongly dependent on the loading direction relative to the layer orientation. The current investigation reveals that the inelastic deformation mechanisms in ice-templated alumina–epoxy composites are strongly influenced by the compressive loading orientation relative to the growth direction of ice crystals. The deformation mechanisms were investigated for the loading directions of 0° (parallel to the growth direction), 45° (to the growth direction), and 90° (to the growth direction). For 0°, kink band formation and longitudinal splitting were observed to be the primary strength limiting mechanisms. Kink band formation could be the primary strength limiting factor and responsible for the catastrophic-type compressive failure response. For the loading directions of 45° and 90°, interface delamination and fracture within the lamella walls and across the alumina–epoxy interfaces were the main deformation mechanisms. These mechanisms significantly reduced the compressive strength but attributed progressive-type failure behavior in ice-templated composites. The knowledge of the inelastic deformation mechanisms in ice-templated ceramic–polymer composites under compressive loading is vital for an improved understanding of structure–mechanical property relationships and hierarchical materials design.

In this paper, we consider a mathematical model to explain, understanding, and to forecast the outbreaks of COVID-19 in India. The model has four components leading to a system of fractional order differential equations incorporating the refuge concept to study the lockdown effect in controlling COVID-19 spread in India. We investigate the model using the concept of Caputo fractional-order derivative. The goal of this model is to estimate the number of total infected, active cases, deaths, as well as recoveries from COVID-19 to control or minimize the above issues in India. The existence, uniqueness, non-negativity, and boundedness of the solutions are established. In addition, the local and global asymptotic stability of the equilibrium points of the fractional-order system and the basic reproduction number are studied for understanding and prediction of the transmission of COVID-19 in India. The next step is to carry out sensitivity analysis to find out which parameter is the most dominant to affect the disease’s endemicity. The results reveal that the parameters η , μ and ρ are the most dominant sensitivity indices towards the basic reproductive number. A numerical illustration is presented via computer simulations using MATLAB to show a realistic point of view.

This work is motivated by the structural gradient observed in natural materials to investigate the influence of the loading direction on the compressive response of ice-templated alumina-epoxy composites. Although this investigation is not on the development of multilayered composites with a structural gradient, the current results can help understand the mechanical behavior and design of such materials. Ice-templated alumina materials were developed from 20 vol% suspensions at high freezing-front velocity (FFV) and from 30 vol% suspensions at high and low FFVs. From porous ceramics, specimens were extracted at different orientations relative to the growth direction of ice crystals and infiltrated with epoxy. The resultant composites varied in ceramic fraction and morphology. For compression along the growth direction of ice crystals, specimens exhibited either high strength with brittle-like (catastrophic) failure or low strength with ductile-like (progressive) failure. Away from growth direction, strength decreased significantly, and failure was ductile-type. The strength exhibited a strong dependence on ceramic fraction and morphology. At each orientation, strength data of both porous ceramics and composites showed significant variability, and Weibull analysis suggested a connection between their strength. Direct visualization revealed the influence of loading orientation and morphology on deformation and failure in composites. Using the Tsai-Hill failure criterion, the role of competitive failure mechanisms on the compressive response of composites was evaluated. From the knowledge of composition, compressive and bend strength of ceramic phase, and yield strength of polymer phase, upper bound and lower bound of strength were predicted, which encompassed the strength of composites.

Ice-templating technique enables the synthesis of novel ceramic materials with directional, anisotropic pores, and the templated structure is highly tunable. Another factor that also drives interest in ice-templated ceramics is that for a comparable level of porosity, the uniaxial compressive strength of these materials can be significantly greater in comparison to that of the conventional open-cell foams. However, the strength advantage is significantly reduced in the materials templated from low solid loading suspensions. Toward this limitation, this study sheds insights into the influence of sucrose (a water-soluble additive) and freezing front velocity (FFV) on microstructure and the uniaxial compressive response of ice-templated sintered lithium titanate (LTO, composition Li4Ti5O12). This study used LTO as a model material. Materials were ice-templated from aqueous suspensions with 20 vol.% LTO powder and sucrose content was varied between 1–4 wt.%. The porosity of the sintered materials was in the range of 60–65 vol.%. Materials processed without sucrose exhibited lamellar morphology and low compressive strength. Sucrose had a marked influence on the connectivity between lamella walls, which significantly increased with sucrose content, and morphology became highly dendritic. The microstructural changes remarkably impacted compressive strength, which increased as high as eight-fold. Moreover, materials processed with sucrose exhibited a significant increase in strength in the continuous brittle crushing regime. By adjusting sucrose content in aqueous suspension and FFV, it is possible to synthesize ice-templated sintered LTO materials with tailored connectivity between lamella walls and harness compressive strength within a wide range of 4–80 MPa.

This study investigates the effects of two different particle sizes (0.3 μ m vs. 0.9 μ m ) on the microstructure and uniaxial compressive response of ice-templated sintered alumina scaffolds as a function of the solids loading of the ceramic suspensions and freezing front velocity (FFV). For a comparable solids loading and FFV, variation of the particle size is observed to have a significant effect on the microstructure of the fabricated scaffolds. Moreover, transition of the pore morphology with the increasing solids loading and FFV is observed to be more drastic for the scaffolds processed from the 0.9 μ m size powder particles compared to the scaffolds processed from the 0.3 μ m size powder particles. Similarly, particle size variation also influenced significantly the relative density and porosity of the scaffolds. Interestingly, in spite of the observed significant differences of the microstructure and relative density, uniaxial compressive stress-strain measurements revealed marginal effects of the particle size variation on the compressive strength. The measured comparable uniaxial compressive response of the sintered alumina scaffolds fabricated from two different particle sizes are rationalized based on the relative density, pore aspect ratio, and interlamellae bridge density.

A number of single and two parameter variational approximations for the LP 01 mode are reported in the literature which has been used to compute the various propagation characteristic parameters, such as, propagation constant, normalised dispersion, splice loss, bending loss etc. for single mode fibers. These studies are limited to optically linear fibers. To our knowledge, these variational approximations have not been used to study the nonlinear optical processes in such fibers. In the present work, using these variational approximations, the generation of self-similar parabolic pulses in graded-index single mode normal dispersive active fibers has been studied. The optimum length L opt of the fiber, after which an input Gaussian pulse turns into a self-similar parabolic pulse, has been computed and the accuracies obtained from these variational approximations have been compared.

Let $A$ be a local complete intersection ring. Let $M,N$ be two finitely generated $A$-modules and $I$ an ideal of $A$. We prove that \[ \bigcup_{i\geqslant 0}\bigcup_{n \geqslant 0}\mathrm{Ass}_A\left(\mathrm{Ext}_A^i(M,N/I^n N)\right) \] is a finite set. Moreover, we prove that there exist $i_0,n_0\geqslant 0$ such that for all $i\geqslant i_0$ and $n \geqslant n_0$, we have \[ \mathrm{Ass}_A\left(\mathrm{Ext}_A^{2i}(M,N/I^nN)\right) = \mathrm{Ass}_A\left(\mathrm{Ext}_A^{2 i_0}(M,N/I^{n_0}N)\right), \] \[ \mathrm{Ass}_A\left(\mathrm{Ext}_A^{2i+1}(M,N/I^nN)\right) = \mathrm{Ass}_A\left(\mathrm{Ext}_A^{2 i_0 + 1}(M,N/I^{n_0}N)\right). \] We also prove the analogous results for complete intersection rings which arise in algebraic geometry. Further, we prove that the complexity $\mathrm{cx}_A(M,N/I^nN)$ is constant for all sufficiently large $n$., Comment: 17 pages, final version

This study investigates the effects of the size of hollow glass microspheres (20 μm vs. 40 μm) and composition on the energy absorption capacity of the silicate glass foams under both the quasistatic (∼10^(−3) s^(−1)) and high-strain rate (∼10^3 s^(−1)) loading conditions. These measurements revealed that while the size difference of the hollow glass microspheres and the foam composition have negligible effects on the uniaxial quasistatic response, their effects were significant under the dynamic loading conditions. The results suggest that the smaller glass microspheres (20 μm) dominated the dynamic behavior of the glass foams in comparison to the larger glass microspheres (40 μm), leading to a significant increase of the energy absorption capacity of the 20 μm-based glass foams at high-strain rates. Glass foams exhibited energy absorption capacity of about 54 kJ/kg under the dynamic loading that is greater in comparison to that of the typical metallic and syntactic foams.

Let $A$ be a Noetherian standard $\mathbb{N}$-graded algebra over an Artinian local ring $A_0$. Let $I_1,\ldots,I_t$ be homogeneous ideals of $A$ and $M$ a finitely generated $\mathbb{N}$-graded $A$-module. We prove that there exist two integers $k$ and $k'$ such that \[ \mathrm{reg}(I_1^{n_1} \cdots I_t^{n_t} M) \leq (n_1 + \cdots + n_t) k + k' \quad\mbox{for all }~n_1,\ldots,n_t \in \mathbb{N}. \], 9 pages

Polymeric outdoor insulators derived from polydimethyl siloxane (PDMS) are replacing conventional ceramic insulators in high voltage power transmission lines because of their improved electrical, mechanical and hydrophobic performance. Major impediments like failure of polymeric insulators due to natural aging by UV radiation from sunlight and electrical tracking have limited their usage. Herein, it is demonstrated about the usage of manganese dioxide based nanoparticles as an effective agent to prevent the UV accelerated aging of polymeric insulators. MnO2 nanoparticles of different shapes and dimension were synthesized using a single step wet chemical reaction between KMnO4 and methyl acetate. Namely, 2D δ-MnO2 nanosheets, 1D α-MnO2 nanowires and 3D α-MnO2 nanorods were formed. These nanoparticles were extensively characterized by various techniques. In the scope of the study, the δ-MnO2 (10−5 S cm−1; 1 MHz) nanosheet demonstrated the lowest electrical AC conductivity and a higher band gap compared to the 1D (10−4 S cm−1; 1 MHz) and 3D variety (10−4 S cm−1; 1 MHz). Owing to the lower electrical conductivity of the δ-MnO2 nanosheet, it was further incorporated at different filler volumes in the polymeric matrix (blend of polydimethyl siloxane/ethylene vinyl acetate) as a UV protector material for the polymer based high voltage composite polymeric insulator. The UV protection ability, induced by the δ-MnO2 nanosheet, was achieved without adversely affecting other properties of the formulated insulator compound material. The optimum properties of the composite were found to be obtained at 3 phr (three parts of δ-MnO2 nanosheet per hundred parts of polymer) loading of the nanosheet. The current work will promise to pave a new pathway for the generation of UV resistant high voltage power transmission line insulator materials. It would be interesting in the future to study the effect of incorporation of manganese dioxide based nanosheets on the UV resistant properties of different polymeric matrices.

The role of specific interactions in the self-assembly process of low molecular weight gelators (LMWGs) was studied by altering the nonbonding interactions responsible for gel formation via structural modification of the gelator/nongelator. This was achieved by modifying pyridyl moieties of bis(pyridyl) urea-based hydrogelator (4&ndash, BPU) and the isomer (3&ndash, BPU) to pyridyl N&ndash, oxide compounds (L1 and L2, respectively). The modification of the functional groups resulted in the tuning of the gelation properties of the parent gelator, which induced/enhanced the gelation properties. The modified compounds displayed better mechanical and thermal stabilities and the introduction of the N&ndash, oxide moieties had a prominent effect on the morphologies of the gel network, which was evident from the scanning electron microscopy (SEM) images. The effect of various interactions due to the introduction of N&ndash, oxide moieties in the gel network formation was analyzed by comparing the solid-state interactions of the compounds using single crystal X-ray diffraction and computational studies, which were correlated with the enhanced gelation properties. This study shows the importance of specific nonbonding interactions and the spatial arrangement of the functional groups in the supramolecular gel network formation.

The present research work was aimed at improving the high field dielectric properties of silicone rubber (SR) composites used for power cable insulation. Liquid silicone rubber composites were developed using two types of clays as filler materials; organically modified montmorillonite (ommt) and calcined, surface treated kaolin with the commercial name Translink 37 (T37). The results revealed that the surface chemistry of the clay had a distinct effect on both dispersion as well as electrical performance of silicone rubber-clay composites. We observed that surface treated kaolin (T37) were well dispersed in the SR matrix, but had adverse impact on the crosslinking kinetics of liquid silicone rubber resulting in higher dielectric loss at low frequencies. On the other hand, organically modified clay showed poor dispersion in the silicone rubber matrix while exhibiting much lower dc conductivity characteristics at high temperature. The agglomerated ommt macroparticles introduced the interfacial traps in SR matrix and charge carriers migration was limited within the matrix.

The current investigation provides insights into microstructure development as a function of sintering temperature within lamella walls of ice-templated ceramics, effects of ceramic platelets on wall microstructure, and the influence of those developments on the compressive mechanical response. The results revealed a profound influence of both on the several aspects of ice-templated ceramics, enabling an improved understanding of the structure-mechanical property relationships in these materials and limitations in the development of the ice-templated ceramic structure. In the materials without platelets, at low-temperature walls were highly porous, at intermediate temperature a pore-free lamella wall with fine-grained microstructure developed, and at high-temperature along with grain growth significant abnormal grain growth occurred as well. More dramatic was the combined effects of temperature and platelets. The effects of platelets were realized at two length scales. Some of the platelets developed lamellar bridges, whereas the platelets that became part of the lamella walls remarkably impacted wall microstructure. The current results strongly suggest that there are significant structural and mechanical strength advantages in the incorporation of large anisometric particles in ice-templated ceramics. The addition of large platelets resulted in a marked increase of compressive strength. A significant structural advantage is that the materials containing platelets exhibited improved stability to structural deformation at higher temperatures compared to the materials without the platelets. Thus, this study shows the importance of deeply probing into the structure-mechanical property relationships of ice-templated ceramics as a function of temperature and composition, providing valuable guidance into the microstructure design of these materials.

Mixing supramolecular gels based on enantiomers leads to re-arrangement of gel fibers at the molecular level, which results in more favorable packing and tuneable properties. Bis(urea) compounds tagged with a phenylalanine methyl ester in racemic and enantiopure forms were syn-thesized. Both enantiopure and racemate compounds formed gels in a wide range of solvents and the racemate (1-rac) formed a stronger gel network compared to the enantiomers. The gel (1R+1S) obtained by mixing equimolar amount of enantiomers (1R and 1S) showed enhanced mechanical and thermal stability compared to enantiomers and racemate gels. The preservation of chirality in these compounds was analyzed by circular dichroism and optical rotation measurements. Analysis of the SEM and AFM images revealed that the network in the mixed gel is a combination of enantiomers and racemate fibers, which was further supported by solid state NMR. The analysis of the packing in xerogels by solid state NMR spectra and the existence of twisted-tape morphology in SEM and AFM images confirmed the presence of both self-sorted and co-assembled fibers in mixed gel. The enhanced thermal and mechanical strength may be attributed to the enhanced intermolecular forces between the racemate and enantiomer and the combination of both self-sorted and co-assembled enantiomers in the mixed gel., We thank University of Iceland Research Fund for financial support. D.G. thanks University of Iceland for the Doctoral Research grant and Z.K. thanks University of Ljubljana for the Erasmus exchange program. We thankfully acknowledge Dr. A. Rawal, The Mark Wainwright Analytical Centre, UNSW for solid state NMR studies and Dr. Sigrídur Jónsdóttir, University of Iceland for solution NMR and Mass spectroscopy. P.T. thanks the Australian Research Council for an ARC Centre of Excellence grant (CE140100036) and A.D.M. thanks the National Health and Medical Research Council for a Dementia Development Research Fellowship (APP1106751). L.F. and A.V. thank the FCT (UID/BIO/04469/2013), COMPETE 2020 (POCI-01-0145-FEDER-006684), and Norte2020 Programa Operacional Regional do Norte (BioTecNorte operation, NORTE-01-0145-FEDER-000004) for rheological studies. The rheological study was supported by a STSM Grant from COST Action CM1402 Crystallize., info:eu-repo/semantics/publishedVersion

In this work, the RF performance comparison of lateral and vertical tunnel FETs is presented in the context of ultra low power (ULP) Internet-of-Things (IoT) sensor node circuit applications. It is demonstrated that at low drive currents $(\sim 1\mu \mathrm{A/\mu m})$ , LTFETs outperform VTFETs by an order higher cut-off frequency $(f_{\mathrm{T}})$ of 10 GHz, maximum oscillation frequency $(f_{\mathrm{MAX}})$ of 100 GHz and 50% higher intrinsic gain (Avo). The results show that the TFETs are promising as ULP devices $(V_{\mathrm{ds}}=0.5$ V or less).

Polymeric composite insulators consisting of core fiber reinforced polymer insulators covered with polydimethylsiloxane (PDMS) housing are now replacing conventional ceramic insulators especially for high-outdoor power transmission lines due to some specific advantages. Unlike ceramics, polymers have relatively shorter life. Outdoor insulators experience different electrical, mechanical, chemical, and thermal stresses during service. The long-term service performance of these insulators and their service life estimation is an important issue, but it is complicated and time-consuming. The objective of the present investigation is to check the rate of property deterioration during service and to find the approximate lifetime. Working insulators with different ages were collected from service, and the changes in mechanical and electrical properties and hydrophobicity of the PDMS cover against aging time were measured. The service life estimated from the change in mechanical properties and surface hydrophobicity (using MATLAB software) was compared with the service life of a new compound subjected to accelerated aging tests. Prediction of service life is helpful for replacement of aged insulators from service to avoid interruption in power transmission.

In this work, several normally dispersive highly nonlinear chalcogenide optical fibers (NDHNCFs) with a step-index profile have been designed and optimized in view of efficient parabolic pulse (PP) generation. A typical NDHNCF is selected such that the group velocity dispersion is highest among them and the corresponding nonlinearity is also very high. The input pulse parameters are optimized to find the lowest possible optimum length (Lopt) of the fiber where the linearly chirped PP is obtained. Further, it is found that for a shorter input pulse width, PP can be generated at a sufficiently smaller length of the NDHNCF with a slight compromise for its misfit parameter. A detailed analysis of the effect of pre-chirping helps to identify the suitable amount of initial chirp for different chalcogenide fibers with a choice of input pulse parameters. Although no improvement in PP generation is found for normal and initially chirped hyperbolic secant pulses, a highly efficient triangular pulse is achieved for a particular value of input pulse energy and the initial chirp parameter. Finally, the comparative study substantiates that our optimized NDHNCF is capable enough to generate quality PP at a length almost 70% shorter than a standard silica-based fiber.

Set $ A := Q/({\bf z}) $, where $ Q $ is a polynomial ring over a field, and $ {\bf z} = z_1,\ldots,z_c $ is a homogeneous $ Q $-regular sequence. Let $ M $ and $ N $ be finitely generated graded $ A $-modules, and $ I $ be a homogeneous ideal of $ A $. We show that (1) $ \mathrm{reg}\left( \mathrm{Ext}_A^{i}(M, I^nN) \right) \le \rho_N(I) \cdot n - f \cdot \left\lfloor \frac{i}{2} \right\rfloor + b \mbox{ for all } i, n \ge 0 $, (2) $ \mathrm{reg}\left( \mathrm{Ext}_A^{i}(M,N/I^nN) \right) \le \rho_N(I) \cdot n - f \cdot \left\lfloor \frac{i}{2} \right\rfloor + b' \mbox{ for all } i, n \ge 0 $, where $ b $ and $ b' $ are some constants, $ f := \mathrm{min}\{ \mathrm{deg}(z_j) : 1 \le j \le c \} $, and $ \rho_N(I) $ is an invariant defined in terms of reduction ideals of $ I $ with respect to $ N $. There are explicit examples which show that these inequalities are sharp., Comment: 14 pages, updated version, to appear in Journal of Algebra

To identify the best possible normally dispersive optical fibers (NDF) in view of efficient triangular pulse (TP) generation, the optimization of several passive NDFs are reported in this work. The study shows that TPs, which sustain over a reasonably good fiber length, can be generated at shorter length when higher values of dispersion and nonlinearity are considered. A suitable NDF with high value of dispersion and nonlinearity is chosen and renamed as normally dispersive highly nonlinear fiber (ND-HNLF). The fiber parameters and pulse conditions are optimized here in such a way that the pulse maintains its triangular shape throughout a longer length in transient state. A detail analysis is performed on generation and stability of triangular pulses through the ND-HNLFs in absence and in presence of gain. When compared, the ND-HNLF with gain is found to be preferable due to their lower input power requirement and lesser broadening of the output triangular pulses whereas passive ND-HNLF performs better in terms of formation of TPs at shorter length and sustainability of those pulses over moderately larger fiber length. It is also shown that the suggested fibers, competent enough to generate stable TPs can be potentially applied in the area of optical signal doubling and a new fiber based approach is mentioned as well for saw-tooth pulse formation.

Let $ R $ be a $ d $-dimensional Cohen-Macaulay (CM) local ring of minimal multiplicity. Set $ S := R/({\bf f}) $, where $ {\bf f} := f_1,\ldots,f_c $ is an $ R $-regular sequence. Suppose $ M $ and $ N $ are maximal CM $ S $-modules. It is shown that if $ \mathrm{Ext}_S^i(M,N) = 0 $ for some $ (d+c+1) $ consecutive values of $ i \geqslant 2 $, then $ \mathrm{Ext}_S^i(M,N) = 0 $ for all $ i \geqslant 1 $. Moreover, if this holds true, then either $ \mathrm{projdim}_R(M) $ or $ \mathrm{injdim}_R(N) $ is finite. In addition, a counterpart of this result for Tor-modules is provided. Furthermore, we give a number of necessary and sufficient conditions for a CM local ring of minimal multiplicity to be regular or Gorenstein. These conditions are based on vanishing of certain Exts or Tors involving homomorphic images of syzygy modules of the residue field., 20 pages, Final version after revision, To appear in Glasgow Mathematical Journal

Due to the internationalisation of food production and distribution, there has been a significant increase of food fraud in recent years. Food fraud can have serious health implications, and it occurs when food manufacturers implement unethical practices such as making false label claims as well as using additives and fillers within their products to increase profitability. This has been a serious concern. Meat adulteration was examined using a well-defined proteogenomic annotation, carefully selected surrogate tryptic peptides and high-resolution mass spectrometry. Selected mammalian meat samples were homogenised and the proteins extracted and digested with trypsin. Chromatography was achieved using a 30-min linear gradient along with a BioBasic C8 100 × 1 mm column at a flow rate of 75 µl min-1. The mass spectrometer was operated in full-scan high-resolution and accurate mass using resolving powers of 140,000 and 17,500 (FWHM) in full-scan MS and MS/MS respectively. Data independent acquisition (DIA) mode was used including 12 DIA MS/MS scans to cover the mass range 600-1200 m/z. Methodically in silico analyses of myoglobin, myosin-1, myosin-2 and β-haemoglobin sequences allow for the identification of a species-specific tryptic peptide mass lists and theoretical MS/MS spectra. Following comprehensive MS, MS/MS or DIA analyses, the method was capable of the detection and identification of very specific tryptic peptides for all four targeted proteins for each animal species tested with observed m/z below 3 ppm compared with the theoretical m/z. The analyses were successfully performed with raw and cooked meat. Specifically, the method was capable of detecting 1% (w/w) of pork or horse meat in a mixture before and after cooking (71°C internal temperature).

Diabetes Mellitus is caused due to disorders of metabolism and its one of the most common diseases in the world today, and growing. Threshold Based Clustering Algorithm (TBCA) is applied to medical data received from practitioners and presented in this paper. Medical data consist of various attributes. TBCA is formulated to effectually compute impactful attributes related to Mellitus, for further decisions. TBCAs primary focus is on computation of Threshold values, to enhance accuracy of clustering results.

We investigate three cases regarding asymptotic associate primes. First, assume $ (A,\mathfrak{m}) $ is an excellent Cohen-Macaulay (CM) non-regular local ring, and $ M = \operatorname{Syz}^A_1(L) $ for some maximal CM $ A $-module $ L $ which is free on the punctured spectrum. Let $ I $ be a normal ideal. In this case, we examine when $ \mathfrak{m} \notin \operatorname{Ass}(M/I^nM) $ for all $ n \gg 0 $. We give sufficient evidence to show that this occurs rarely. Next, assume that $ (A,\mathfrak{m}) $ is excellent Gorenstein non-regular isolated singularity, and $ M $ is a CM $ A $-module with $\operatorname{projdim}_A(M) = \infty $ and $ \dim(M) = \dim(A) -1 $. Let $ I $ be a normal ideal with analytic spread $ l(I) < \dim(A) $. In this case, we investigate when $\mathfrak{m} \notin \operatorname{Ass} \operatorname{Tor}^A_1(M, A/I^n)$ for all $n \gg 0$. We give sufficient evidence to show that this also occurs rarely. Finally, suppose $ A $ is a local complete intersection ring. For finitely generated $ A $-modules $ M $ and $ N $, we show that if $ \operatorname{Tor}_i^A(M, N) \neq 0 $ for some $ i > \dim(A) $, then there exists a non-empty finite subset $ \mathcal{A} $ of $ \operatorname{Spec}(A) $ such that for every $ \mathfrak{p} \in \mathcal{A} $, at least one of the following holds true: (i) $ \mathfrak{p} \in \operatorname{Ass}\left( \operatorname{Tor}_{2i}^A(M, N) \right) $ for all $ i \gg 0 $; (ii) $ \mathfrak{p} \in \operatorname{Ass}\left( \operatorname{Tor}_{2i+1}^A(M, N) \right) $ for all $ i \gg 0 $. We also analyze the asymptotic behaviour of $\operatorname{Tor}^A_i(M, A/I^n)$ for $i,n \gg 0$ in the case when $I$ is principal or $I$ has a principal reduction generated by a regular element., 34 pages

Background Fermentative hydrogen production is an attractive means for the sustainable production of this future energy carrier but is hampered by low yields. One possible solution is to create, using metabolic engineering, strains which can bypass the normal metabolic limits to substrate conversion to hydrogen. Escherichia coli can degrade a variety of sugars to hydrogen but can only convert electrons available at the pyruvate node to hydrogen, and is unable to use the electrons available in NADH generated during glycolysis. Results Here, the heterologous expression of the soluble [NiFe] hydrogenase from Ralstonia eutropha H16 (the SH hydrogenase) was used to demonstrate the introduction of a pathway capable of deriving substantial hydrogen from the NADH generated by fermentation. Successful expression was demonstrated by in vitro assay of enzyme activity. Moreover, expression of SH restored anaerobic growth on glucose to adhE strains, normally blocked for growth due to the inability to re-oxidize NADH. Measurement of in vivo hydrogen production showed that several metabolically engineered strains were capable of using the SH hydrogenase to derive 2 mol H2 per mol of glucose consumed, close to the theoretical maximum. Conclusion Previous introduction of heterologous [NiFe] hydrogenase in E. coli led to NAD(P)H dependent activity, but hydrogen production levels were very low. Here we have shown for the first time substantial in vivo hydrogen production by a heterologously expressed [NiFe] hydrogenase, the soluble NAD-dependent H2ase of R. eutropha (SH hydrogenase). This hydrogenase was able to couple metabolically generated NADH to hydrogen production, thus rescuing an alcohol dehydrogenase (adhE) mutant. This enlarges the range of metabolism available for hydrogen production, thus potentially opening the door to the creation of greatly improved hydrogen production. Strategies for further increasing yields should revolve around making additional NADH available.

Residual strains in ferroelectrics are known to adversely affect the material properties by aggravating crack growth and fatigue degradation. The primary cause for residual strains is strain incompatibility between different microstructural entities. For example, it was shown in polycrystalline ferroelectrics that residual strains are caused due to incompatibility between the electric-field-induced strains in grains with different crystallographic orientations. However, similar characterization of cause-effect in multidomain ferroelectric single crystals is lacking. In this article, we report on the development of plastic residual strains in [111]-oriented domain engineered BaTiO(3) single crystals. These internal strains are created due to strain incompatibility across 90° domain walls between the differently oriented domains. The average residual strains over a large crystal volume measured by in situ neutron diffraction is comparable to previous X-ray measurements of localized strains near domain boundaries, but are an order of magnitude lower than electric-field-induced residual strains in polycrystalline ferroelectrics.

This paper describes experimental data on a polycrystalline nickel subjected to compressive loads induced in a split Hopkinson pressure bar test. A perpendicular bias magnetic field with respect to the loading direction is used to orient the domains and a pick-up coil measures the magnetic response of the sample during loading. Utilizing this experimental configuration, this study investigated the coupled effects of the magnetic and mechanical fields on domain wall motion in a polycrystalline magnetostrictive material (Ni) during the high-rate elastic loading. The experimental measurements reveal that the magnitude of the stress-induced magnetization change is dependent upon bias magnetic field.