Prismatic Shape Research Articles

Otoliths morphology and age-record in Bagre panamensis (Siluriformes: Ariidae) inhabiting at the southeast of Gulf of California

Among Bagre genera, there is a high variation in the estimation of age, a concern due to overexploitation risk in fisheries because of age underestimation. Bagre panamensis is an important fishery resource of the Mexican Pacific and the Gulf of California. Its age is known from otoliths, but its accuracy needs to be confirmed, and the periodicity of the otoliths record validated. The external morphology, some microstructure attributes, and age record of B. panamensis' otoliths were described from 371 specimens collected southeast of the Gulf of California. The lapilli otoliths were larger than the sagittae and asterisci otoliths. The lapilli otoliths present aragonite crystals with a prismatic shape, and their growth is radial, from the core to the otolith edge. The lapilli otoliths form an annual growth ring, defined by the slowdown in the growth that occurs during April to July, during the breeding season. The ages of the individuals ranged from 1 to 15 years, and the applied method is considered adequate and accurate for its estimation (otolith cross-sectioning and red-neutral staining).

RENiO3 Single Crystals (RE = Nd, Sm, Gd, Dy, Y, Ho, Er, Lu) Grown from Molten Salts under 2000 bar of Oxygen Gas Pressure

The electronic properties of transition-metal oxides with highly correlated electrons are of central importance in modern condensed matter physics and chemistry, both for their fundamental scientific interest, and for their potential for advanced electronic applications. The design of materials with tailored properties has been, however, restricted by the limited understanding of their structure-property relationships, which are particularly complex in the proximity of the regime where localized electrons become gradually mobile. RENiO3 perovskites, characterized by the presence of spontaneous metal to insulator transitions, are one of the most widely used model materials for the investigation of this region in theoretical studies. However, crucial experimental information needed to validate theoretical predictions is still lacking due to their challenging high-pressure synthesis, which has prevented to date the growth of sizable bulk single crystals with RE different than La, Pr and Nd. Here we report the first successful growth of single crystals with RE = Nd, Sm, Gd, Dy, Y, Ho, Er and Lu and sizes up to ~75 {\mu}m, grown from molten salts in temperature gradient under 2000 bar oxygen gas pressure. The crystals display regular prismatic shapes with flat facets, and their crystal structures, metal-insulator and antiferromagnetic order transition temperatures are in excellent agreement with previously reported values obtained from polycrystalline samples. The availability of such crystals opens access to measurements that have hitherto been impossible to conduct. This should contribute to a better understanding of the fascinating properties of materials with highly correlated electrons, and guide future efforts to engineer transition metal oxides with tailored functional properties.

Self-powered solar-blind ultraviolet photodetector based on α-Ga2O3 nanorod arrays fabricated by the water bath method

In this paper, α-Ga2O3 nanorod arrays (NRAs) with preferential growth along the (110) direction were successfully prepared on the FTO substrate by the water bath method. With the help of a scanning electron microscope (SEM), X-ray diffractometer (XRD), and Raman spectrometer (Raman), the crystal structure and morphology characteristics of α-Ga2O3 NRAs were studied. On this basis, a photoelectrochemical (PEC) solar-blind ultraviolet photodetector based on the α-Ga2O3 NRAs was fabricated, and the photoelectric performance of the device was analyzed in detail through the PEC test system, and the working mechanism of the device was further discussed. The results show that the prepared α-Ga2O3 NRAs have good crystal quality which is closely arranged on the substrate and a quadrangular prism shape from the top view. The constructed α-Ga2O3 NRAs PEC photodetector shows typical solar-blind ultraviolet response characteristics and stable self-powered ability. Meanwhile, the device exhibited a high photo-dark current ratio (PDCR), responsivity (R) and detectivity (D*) of 1.01×103, 11.34 mA/W and 2.68×1011 Jones, respectively, as well as superior wavelength selectivity and fast response. This work confirms that α-Ga2O3 NRAs prepared by the water bath method have potential application prospects in highly sensitive and fast response PEC self-powered solar-blind ultraviolet photodetectors.

Features of clay soil deformation under triaxial block regime cyclic loading, taking into account the formation of micro and macro-cracks

The main purpose of this paper is to study the parameters of strength and deformation of clay soil in conditions of triaxial compression under block regime cyclic loading. To date, there are no data on the results of studies under this loading mode. Theoretical and experimental studies of the strength and deformability of clay soil of triaxial compression 0^02=03 under block regime cyclic loads are carried out. A distinctive feature of the experimental studies is that they were carried out in devices of triaxial compression of a prismatic shape with an aspect ratio of 100x 100x200mm. In the study of vibration creep deformations and changes in the fatigue resistance to the destruction of clay soils under triaxial regime block cyclic loading. It is established that the stress-strain state, deformation, and fatigue strength of soil vary depending on the sequence of alternating blocks with different values of the maximum load of the cycle. The developed and obtained equations describing the deformation of the soil under these conditions with the development of micro-cracks observed in experiments of hardening and softening effect of inhibition at different stages of cyclic triaxial compression allow to accurately estimate vertical deformation (settlement) bases under regime loading and to obtain reliable and economical design solutions.

Simulation of steam/air leakage through small-scale cracked concrete specimen

At the Material Testing and Research Institute (MPA Karlsruhe) leakage experiments with concrete specimens containing a single penetrating crack were performed on behalf of GRS. The specimens had a prismatic shape and the dimensions 4.0 cm × 4.0 cm × 11.0 cm. The crack width was adjustable and ranged from 0.05 mm to 0.25 mm in the experiments. On top of the leakage measurement two sets of additional measurements were performed. In leakage experiments with air at room temperature the exit velocity of the leakage flow was measured with a hot-wire anemometer. The measured velocities were compared to the velocities calculated by leakage rate formulas. The formulas compare well to measurement results. Differences depend greatly on the crack width and the respective assumptions on the friction coefficient proposed by the authors. In a second set of experiments, hot air and hot steam/air mixtures were used. At the beginning of the experiment the specimen had room temperature; due to heat transfer from the leaking fluid to the specimen and the thermal expansion of the specimen, the crack width was reduced, and the leakage rate significantly decreased. The leakage process including fluid-structure interaction was simulated using the coupling of the thermal-hydraulic system code ATHLET, which has been developed and validated by GRS, and the structure mechanical finite element code ANSYS Mechanical.

Influences of sample shape, voltage gradient, and electrode surface form on the exergoeconomic performance characteristics of ohmic thawing of frozen minced beef

In the present study, it was aimed to investigate the exergoeconomic performance of ohmic thawing (OT) system during the thawing of frozen minced meat (lean beef). The effects of the sample shape (X: 13 × 4 × 3 cm, Y: 13 × 6 × 2 cm, Z: cylinder with a height of 13 cm and diameter of 3.91 cm), electrode surface form (titanium foil with smooth surface, titanium electrode with needle-type surface and titanium electrode with pyramid-type surface), and voltage gradients (10, 13, and 16 V/cm) were investigated. Lower exergoeconomic values were obtained for the cylindrical shape compared to the rectangular prism. The lowest exergy efficiency value (12.45 ± 0.42), is was obtained for the cylindrical shape at 10 V/cm voltage gradient with titanium foil electrode. The needle-type surface electrodes had higher performance values than other electrodes. The exergoeconomic performance increased as the voltage gradient increased. The lowest unit exergy cost (72.40 ± 2.8) was obtained for rectangular prism shape at 16 V/cm with needle-type electrode. The comprehensive exergoeconomic evaluation in this study exhibited the energy utilization effectiveness and unit exergy cost of OT.

Finite element analysis on flexural behavior of nonprismatic longitudinal section reinforced concrete deep beam

Increasing of building constructions demand affects the innovation for developing structural elements, especially in the beam element known as deep beams. The deep beam is a popular beam with an adequate ratio of a/d < 1.0. Therefore, Compared to the standard beam, The strength of the deep beam shows better. It also can be applied to various construction. Based on observations in the field, the length of the cross-section of the deep beam varies significantly, starting from the prismatic and non-prismatic shapes. Therefore, this research has conducted to determine the effect of non prismatic longitudinal section variations on the RC deep beam behavior using finite element method. The simulation model analyzed consists of one prismatic longitudinal section and two types of the non-prismatic longitudinal section. The result shows that the non-prismatic longitudinal of the deep beam gives effects on slightly decreasing flexural load, ductility and failure mode. The failure modes shown in models show the same characteristics, which are both experiencing shear failure.

Silver nanoprisms as plasmonic enhancers applied in the photodynamic inactivation of Staphylococcus aureus isolated from bubaline mastitis

Mastitis is a bacterial infection that affects all lactating mammals, and in dairy cattle, it leads to a reduction in their milk production and, in worse cases, it may lead to animal death. One viable therapeutic modality for overcoming bacterial resistance can be photodynamic inactivation (PDI), a therapeutic modality for bacterial infection treatment. One of the main factors that can lead to an efficient PDI process is the association of metallic nanoparticles in the close vicinity of photosensitizers, which has shown promising results due to localized surface plasmon resonance phenomena. In this work, methylene blue (MB) molecules were associated with Ag prismatic nanoplatelets (AgNPrs) to use as PDI photosensitizer against Staphylococcus aureus isolated from bubaline mastitis. The optical plasmonic activity of AgNPrs was tuned to the MB absorption region (600–700 nm) by inducing their growth into prismatic shapes by a seed-mediated procedure, using poly (sodium 4-styrene sulfonate) as the surfactant. A simulation on the plasmonic properties of the nanoprisms, applying particle size within the dimensions determined by TEM image analysis (d = 32 ± 6 nm), showed a 30 % increase of the incident field on the prismatic tips. Photodynamic results showed that the electrostatic AgNPr-MB conjugates promoted enhancement (ca. 15 %) of the reactive oxygen species production. Besides, PDI mediated by AgNPrs―MB led to the complete inactivation of the mastitis S. aureus strain after 6 min inactivation, in contrast to PDI mediated by MB, which reduced less than a 0.5 bacterial log. Thus, the results show this plasmonic enhanced photodynamic tool's potential to be applied in the inactivation of multi-resistant bacterial strains.

MECHANISM OF DISORDER GENESIS IN CELLULOSE MICROFIBRILS

"We discuss the possible mechanism of genesis of disordered regions in cellulose microfibrils. In our work, we show that obstacles stopping the growth of nanofibrils and the further deformation of nanofibrils may be the reasons for disorder. In this case, the initial prismatic shape of nanofibrils becomes corrugated and regions, where cellulose chains lose their initial straight configuration, appear in it. If a pack of thus deformed nanofibrils form a microfibril, then it contains disordered regions of two types. The first one consists in boundary layers, which separate nanofibrils from each other. The second type represents amorphous regions located inside each nanofibril. In this discussion, we use the linear theory of elasticity. With its help, we estimated longitudinal dimensions of cellulose crystallites and then compared them with values of such sizes calculated based on experimental data. The experimentally obtained values turned out to be, to a certain extent, greater than the theoretically estimated ones."

On manipulating the thermoelectric potential of p-type ZnO by nanostructuring

Throughout this work, ZnO nanoparticles were produced by a simple co-precipitation method, in which the volume of the basic solution (NaOH, 5–30 ml) was varied to understand its effect on the properties of the nanoparticles. A structural and morphological effect was observed, namely a change in reflections between 2θ=31.75°(100) and 2θ=34.4°(002) peaks. At the same time, nanoparticles changed from a hexagonal prism shape to a desert-rose stones structure for high base concentrations. The transport measurements were performed from room temperature (RT) up to 340 K. At RT, a correlation between the Seebeck coefficient and the electrical conductivity was achieved, whereas the thermal conductivity behaves distinctly. A thermal conductivity value of 0.5 W m-1 K−1 was observed, which is two orders of magnitude lower than the bulk counterpart. The behaviours of the PF and ZT also reveal the different influences of the electrons and the phonons for the different nanostructures, since the electronic phenomena predominate in the hexagonal prism structures, the phonon phenomena predominate in the desert-rose stones, due to the reduced dimension of these structures. For higher temperatures, a thermal activation model was used to determine the Activation Energy (Ea), leading to values in the hundredths of meV range, with higher values for the volumes of NaOH where a mixture of the two types of structures is observed, where the presence of different interfaces created a barrier for the carriers to pass from grain to grain.

Offretite Zeolite Single Crystals Synthesized by Amphiphile-Templating Approach.

Offretite zeolite synthesis in the presence of cetyltrimethylammonium bromide (CTABr) is reported. The offretite crystals were synthesized with a high crystallinity and hexagonal prismatic shape after only 72 h of hydrothermal treatment at 180 °C. The CTABr has dual-functions during the crystallization of offretite, viz. as structure-directing agent and as mesoporogen. The resulting offretite crystals, with a Si/Al ratio of 4.1, possess more acid sites than the conventional offretite due to their high crystallinity and hierarchical structure. The synthesized offretite is also more reactive than its conventional counterpart in the acylation of 2-methylfuran for biofuel production under non-microwave instant heating condition, giving 83.5% conversion with 100% selectivity to the desired product 2-acetyl-5-methylfuran. Hence, this amphiphile synthesis approach offers another cost-effective and alternative route for crystallizing zeolite materials that require expensive organic templates.

Low‐energy technology for producing anhydrite in the CaCO3–H2SO4–H2O system derived from industrial wastes

AbstractBACKGROUNDA high‐quality anhydrite binder could be produced due to the exergy of sulfuric acid in the CaCO3–H2SO4–H2O system derived from industrial wastes. Waste of sulfuric acid derived from the production of heat‐resistant fibers and wastes of limestone that was formed on the metallurgical enterprise were used for the synthesis of anhydrite. Such a product is safe from an environmental point of view and has many advantages, both operational and economic, over standard gypsum binders.RESULTSThe optimal technological parameters have been established and a technological scheme for producing anhydrite excluding the stage of calcium sulfate dihydrate formation has been proposed. Anhydrite production in the CaCO3–H2SO4–H2O system, due to the exergy of sulfuric acid, is a promising technology to replace the traditional thermal technology for producing anhydrite. This technology can reduce fuel costs because the required synthesis temperature is 95–105 °С, instead of 800–1000 °С in the traditional one, and this significantly reduces the cost of manufactured products.CONCLUSIONThe maximum yield of synthetic anhydrite was provided by a limestone suspension taken in a stoichiometric amount. This neutralizing agent makes it possible to obtain particles of a prismatic shape, the size of which is generally more than 20 μm. © 2021 Society of Chemical Industry (SCI).

Modeling of thin sheet forming processes by combining solid-shell finite element with isotropic elastoviscoplastic model. Application to magnetic pulse forming processes

Sheet metal alloys are used in many industries to save material, reduce weight and improve the overall performance of products. For the last decades, many types of elements have been developed to resolve the locking problems encountered in the simulation of thin structures. Among these approaches, a family of assumed-strain solid-shell elements has proved to be very efficient and attractive in simulating thin 3D structures with various constitutive models. Furthermore, these elements are able to account for anisotropic behavior of thin structures since isotropic yield functions cannot capture the real physics of some forming processes. In this work, von Mises isotropic yield criterion with Johnson-cook hardening model are combined with a linear prismatic solid-shell element to simulate sheet metal forming processes. A new element assembly technique has been developed to permit the assembly of prismatic elements in a tetrahedral element-based software. This technique splits the prism into multiple tetrahedral elements in such a way that all the cross-terms are accounted for. Furthermore, a tetrahedral based partitioning code has been modified to account for the new prismatic element shape without changing the core structure of the code. More accurate results were obtained using low number of solid-shell elements compared to its counterpart tetrahedral element (MINI element). This reduction in the number of elements accelerated the simulation, especially in the coupled magnetic-structure simulation used for magnetic pulse forming process. The proposed element and criteria are implemented into FORGE (in-house code developed at CEMEF) for simulating magnetic pulse forming process.

Numerical solution of a boundary value problem with effective boundary conditions for calculation of gravity

Forward modeling of gravity field on the base of boundary-value problem solution is a promising technique against traditional summation methods. To calculate gravity of a body with known physical and geometrical properties, one can firstly solve a boundary-value problem for gravitational potential and then calculate its gradient. This approach is more common, but it requires two operations. Another approach is to solve a boundary value problem formulated directly for gravity itself. The main difficulties for methods based on boundary-value problem solution are proper boundary condition, domain size and domain discretization. For the first approach there are plenty of works dealing with these cases in contrast with the second approach. In this paper, authors discuss and compare boundary conditions of two types: the Dirichlet and Robin, in terms of approximation accuracy for the second approach using the finite element method. Calculation results are presented for a test problem, when the gravitational field is produced by a homogeneous body in the shape of a right rectangular prism. A more effective boundary condition is a Robin type condition derived from a simple asymptotic approximation of the gravitational field by the equivalent point mass.

Influence of Cr3C2 and VC Content on WC Grain Size, WC Shape and Mechanical Properties of WC-6.0 wt. % Co Cemented Carbides.

In this paper, the influences of Cr3C2/VC content on WC grain size, WC grain shape and mechanical properties of WC–6 wt. % Co cemented carbides were investigated. The results showed that the grain size first rapidly decreased and then slightly decreased with the increasing Cr3C2/VC content, and VC led to finer grain size and narrower size distribution. HRTEM/EDS analysis of the WC/Co interface indicates that the segregation concentration of V is much larger than that of Cr, which may be a strong response to the higher inhibition efficiency of VC. The addition of Cr3C2 induced triangular prism shape WC grains while VC generated stepped triangular prism grains. Despite the grain growth inhibitor (GGI) mechanisms of Cr3C2/VC have been extensively studied in the literature, the doping amount, especially the doping limit, has not been systematically investigated. In this work, the saturated solubilities of Cr and V in cobalt binder phase along with carbon content hare been predicted based on thermodynamic calculations. Based on the theoretical calculations, the doping amount of Cr3C2/VC is designed to be gradually increasing until more or less over their maximum solubilities in the binder phase, thereby investigating the subsequent microstructure and mechanical properties. When the doping of Cr3C2/VC exceeds the maximum solubility in Co phase, Co-rich Cr-carbides and Co-deficient V-carbides would form respectively, which were detrimental to the transverse rupture strength (TRS) and impact toughness. The hardness increased with the increasing Cr3C2/VC content, while the fracture toughness decreased with the increasing Cr3C2/VC content. The TRS initially enhanced and then declined, but the stepped triangular prism shape grains and low fraction of WC/Co interface in WC–6Co–VC cemented carbide led to a more pronounced decline in the TRS. The sample with 0.6 wt. % Cr3C2 addition had good comprehensive mechanical properties, its hardness, fracture toughness and TRS were 1880 kg/mm2, 9.32 MPa·m1/2 and 3450 MPa, respectively.

Concept of Geometry in Penataran Temple

This study aims to describe the results of exploring the shapes in Penataran Temple, cultural relics accompanied by geometric concepts. This research uses explorative-descriptive research because it is suitable for uncovering mathematical cases related to Ethnomathematics. The data analysis technique used in this research is qualitative. In this study, an ethnographic approach was used, accompanied by interviews, collecting documentation, or analyzing literature about Penataran Temple as data collection techniques. This study concludes that the relationship between culture and building structure in Penataran Temple has always been attached to the concept of geometry in the material. Wake up flat and build space. In these buildings, the forms are applied in mathematical objects such as in flat plane geometry and space shapes. As in this study results, there are several structures, namely cuboid and right triangular prism and plane shape, in an isosceles triangle.

Leaf anatomical traits and their ecological significance for Acrostichum aureum (Pteridaceae), a remarkable fern species growing in mangroves

Mangroves are naturally stressful habitats, with high salinity, regular flooding, strong winds, high temperatures, and muddy, hypoxic soils, requiring adaptations in plant anatomy. In this sense, we present a description of the leaf anatomy of Acrostichum aureum, a remarkable fern species growing in mangroves, focusing on novelties and the significance of the traits for adaptation to mangrove conditions. The leaves were amphistomatic with anomocytic stomata at the same level as the other epidemic cells, and there was a uniseriate hypodermis on both surfaces of the lamina. A dense spongy parenchyma was present in the lamina with limited number of intercellular spaces. We observed sclerenchyma fibers in the costae (3–5 layers) immediately below the epidermis and surrounding the vascular bundles, which were amphicrival (1) and bicollateral (4) in the costae, and collateral and bicollateral in the mesophyll (4–6). In the costae, the endodermis was uniseriate with Casparian strip. The pericycle was interrupted, uniseriate, with varied cell sizes, indicating activity. Idioblasts containing isolated calcium oxalate crystals with a prismatic shape occurred in the epidermis, hypodermis, and sclerenchyma. Some anatomical traits of A. aureum are similar to those reported to angiosperms in mangroves, such as the presence of a thick cuticle, amphistomaty, hypodermis, CaOx crystals, and intercellular spaces, indicative of ecological convergence. These traits are potentially involved in promoting resistance to water loss, enhanced photosynthesis, avoidance of photoinhibition, mechanical resistance, resistance to herbivory, homeostasis, and detoxification.

The Wentzel-Kramers-Brillouin approximation for light scattering by horizontally oriented prismatic particles

In this research, we propose a simple approximation technique based on the decomposition of particles and on the Wentzel-Kramers-Brillouin approximation (WKB). The latter allows us to express analytically the expression of the form factor of a particle of a regular prismatic ice crystal shape. Our focus will be on studying the light scattering by horizontally oriented prismatic particles which rotate about their principal axes. To illustrate our formalism, a few numerical examples will be analyzed.

Chemical constituents and phytochemical properties of floral maize pollen.

Currently, bee-gathered pollen (bee pollen) is commonly used worldwide as a dietary supplement and is recognized for its curative properties. Floral pollen is also important but is less recognized due to a lack of investigation. This study aims to determine the morphological characteristics and nutritional and phytochemical properties of floral maize pollen. Fresh pollen grains harvested from a farm of maize plants are yellow in colour and spheroid in shape. They change to amber and indented prismatic solid shapes when dehydrated. The main composition of floral maize pollen is carbohydrates (44.30±3.73%), followed by moisture (23.38±5.73%), crude proteins (17.16±3.13%), crude fibres (9.56±0.92%), and ash (4.98±0.11%), while the lowest content is observed for crude fats (0.62±0.06%). The predominant mineral is potassium (768.50±11.40 mg 100 g-1), followed by sodium (695.10±9.70 mg 100 g-1), calcium (147.20±12.60 mg 100 g-1), and magnesium (97.30±2.9 mg 100 g-1). The microelements (with average values) consist of iron (49.50±3.30 mg 100 g-1) and zinc (30.00±3.70 mg 100 g-1). Excellent phytochemical properties add value to floral maize pollen. Maize pollen contains a high total phenolic content (TPC) and total flavonoid content (TFC) of 783.02 mg GAE 100 g-1 and 1706.83 mg QE 100 g-1, respectively, and possesses strong antioxidant activity of 10.54 mg mL-1. Maize floral pollen and derived products can serve as future food resources for human consumption and as a source of functional and bioactive compounds in nutraceutical and pharmaceutical industries.

Finite Element Analysis Study on Lattice Structure Fabricated Using Corn Husk Fibre Reinforced Recycled Polystyrene Composite

This research investigated the lattice structure fabricated using corn husk fibre reinforced recycled polystyrene composite using Finite Element Analysis (FEA). The material’s properties of this composite material were obtained from previous study. Then, the lattice structure of lattice structure was created using Creo® software and the FEA simulation was done by ANSYS software. In this study, the lattice structures were created using triangular prism and hexagonal prism. The analysis was divided into two conditions: 1) lattice structure with different prism shape and similar surface area, 2) lattice structure with varies of strut thickness and 3) lattice structure with different prism shape and similar lattice parameter. The results show the lattice structure with triangular prism have more structural integrity than hexagonal prism. Then, lattice structure with triangular prism can be built with lesser material but stronger and stiffer than lattice structure with hexagonal prism.