Search

The article discusses the features of manufacturing the "Cartridge lifting bowl" part by the WAAM method with subsequent machining. The problems that can be encountered in the printing and processing process are identified, and ways to solve them are proposed. Optimal printing strategies have been selected to avoid various defects in welded joints. A promising strategy for manufacturing a part with a cellular structure made of bimetallic composite ER70S6 - ER309LSI was also considered, which helped to facilitate the design without significant loss of strength characteristics. [ABSTRACT FROM AUTHOR]

Lipid droplets (LD) are cellular organelles consisting of a central core of neutral lipids, such as triglycerides and sterol esters, surrounded by a phospholipid monolayer. Quantification of the number, size, and distribution of lipid droplets within cells can provide valuable insights into cellular metabolism, lipid dynamics, and lipid-related diseases. Hence, it is necessary to segment lipid droplets from the cells. Segmenting LDs typically involves image-analysis techniques and algorithms that can differentiate droplets from the background and other cellular structures. In this study, a U-Net-based convolutional neural network (CNN) architecture was designed to segment the LD from the cell. The proposed method achieved accuracy of 99.08%, precision of 87.78%, recall of 86.91%, dice index of 0.8668 and Jaccard index of 0.7725. [ABSTRACT FROM AUTHOR]

When used in treatments, stem cells have the potential to heal many previously incurable illnesses. Existing stem cell application techniques, however, are insufficient since these cells are used directly independent of growing medium or subgroup. Researchers, for example, do not consider the source, culture method, application angle, or function of mesenchymal stem cells (MSCs) when using them in cell therapy (soft tissue regeneration, hard tissue regeneration, suppression of immune function, or promotion of immune function). By combining machine learning methods (such as deep learning) with data sets obtained through single-cell RNA sequencing (scRNA-seq), we can discover the hidden structure of these cells, predict their effects more accurately, and effectively use subpopulations with differentiation potential for stem cell research. ScRNA-seq technique has revolutionised transcription research because it can express single-cell genes with single-cell anatomical accuracy. This powerful technology, however, is subject to biological and technical noise, making data processing computationally difficult. [ABSTRACT FROM AUTHOR]

Crash boxes are typically designed to promote characteristics in energy absorption from progressive buckling during impact. However, the conventional design often has limitations in lightweight design and passenger protection. Thus, truss-lattice and cellular structures offering superior energy-absorbing capacity are implemented in crash box design. This work investigates the crushing behaviors and characteristics of square-tube crash boxes filled with truss-lattice and cellular structures with the objectives of lightweight design while improving the specific energy absorption and mean-crushing forces and lowering the initial peak crash force. The crushing efficiency of the crash boxes between four different types of structures: conventional, BCC, FCC, and Primitive-TPMS, are evaluated and compared using the nonlinear explicit dynamics finite element technique via LS-DYNA. The lattice and cellular structures perfectly show progressive deformation under impact with an excellent potential to absorb energy. The nodal equivalent technique is recommended for the model analyses for the crash boxes with filler structures. The fillers are shown to enhance the crashworthiness of the conventional crash box by controlling the whole deformation so that it remains progressive bucking failure. According to the analysis results, a crash box filled with Primitive-TPMS presents the highest crushing performance and this design is proposed for next-generation vehicles. [ABSTRACT FROM AUTHOR]

The intricate cellular structure within the organ of Corti (OoC) provides the structural basis for how the stereocilia bundles of the hair cells are stimulated, which triggers the mechanoelectrical transduction channels. This intricate process remains elusive, and the stimulation mechanism of the inner hair cell (IHC) stereocilia is under heated debate. Recent experimental data on micromechanics of the OoC and IHC stereocilia motion motivate modeling studies to understand the detailed cellular motion within OoC. However, such a model is not computationally feasible for a full-length model of the cochlea. Current work develops and examines a slice modeling technique that considers the stimulation input location and wavenumber at the slice location. This slice model is compared to results from a full-length box model. [ABSTRACT FROM AUTHOR]

In the present paper the DSMC method is used to simulate numerically emergence and development of instabilities in supersonic free shear flows. The considered flows include a mixing layer between two supersonic streams, indeaa;y expanded jet issuing from a plane nozzle into a supersonic coflow, underexpanded plane and round jets. In contrast with typical continuum simulations, no artificial disturbances are introduced into the flow. Nevertheless, the statistical fluctuations inherent in the DSMC method are sufficient to trigger the development of hydrodynamic instabilities. The processes of vortex formation, growth and pairing have been successfully reproduced, mean and pulsation characteristics of the unstable flows have been obtained. The statistical fluctuations in the DSMC are usually many times greater than physical fluctuations but the general scenario of instabilities development is in good agreement with data of continuum simulations and experiments. The shock cell structure of underexpanded supersonic jets has also been reproduced. [ABSTRACT FROM AUTHOR]

This paper introduces a novel multi-directional speaker, named MuDiS, which utilizes a parametric array to generate highly focused sound beams in multiple directions. The system capitalizes on air nonlinearity to reproduce sound from ultrasounds, successfully overcoming challenges inherent in traditional parametric arrays, such as transducer size and wavefront shape. It supports three important features simultaneously: independent beams, wide-angle digital steering, and unintended leakage suppression. To address these challenges, we designed a specialized cell structure that connects ultrasonic transducers, redirecting an approximately omnidirectional wavefront with optimal interspacing. An optimization-based algorithm is developed to minimize unintended leakages, and a nonlinear distortion reduction scheme is proposed to enhance sound quality. The paper showcases a prototype demonstrating the system's capabilities as a multidirectional speaker with a wide sound projection angle. Experimental results validate the effectiveness of our approach. The proposed multi-beam projection system rivals the performance of commercially available single-beam projection directional speakers, and improved steering angle and sound fidelity compared to multi-beamforming performance using traditional parametric arrays. [ABSTRACT FROM AUTHOR]

To enhance the quality of parts and decrease cycle time in injection molding, appropriate control of mold temperature is required. To achieve these objectives, a novel mold design has been suggested that has conformal mold heating and cooling capabilities using carbon nanotube (CNT) heater. The CNT heater was installed in a curved mold to obtain conformal mold heating capability. An additively manufactured microcellular structure was placed underneath the CNT film heater to improve heating efficiency by playing as a thermal insulator. Additionally, the microcellular structure serves as a heat exchanger during conformal and rapid mold cooling by circulating a coolant through its porous structure. By using both the CNT film heater and microcellular metamaterial, the mold temperature changes uniformly during the thermal cycle, which is an improvement over previous mold heating methods. The proposed technology can improve the part quality as well as productivity of molding processes. [ABSTRACT FROM AUTHOR]

Allergic rhinosinusitis (AR) is a type 1 hypersensitivity reaction's clinical manifestation. The emergence of illness symptoms involves a variety of interactions involving immune system components such as cells, mediators, cytokines, neuropeptides, adhesion molecules, and so on. Aim of the study: to compare patient and healthy control data to see if particular blood and local cytokines, as well as IgE molecules, are involved in the etiology of AR. Materials and methods: the laboratory diagnosis in the national center laboratory in Baghdad Province, Iraq. Patients with runny noses, nasal congestion, and sneezing were enrolled in the trial with their agreement at the Allergy Specialization Center Allergy and Immunology Clinic, administered by Internal Medicine and Ear and Throat Clinics. There were 100 patients in the experimental group. A control group of 50 healthy persons in the same age range, on the other hand, was developed. In the group of patients, 50 (50%) IAR and 50(50%) PAR. Mean of the age in patients with AR was 34.36 ± 12.83 and in the control group: 34.18 ± 11.9. The patients were divided into two groups. 26(52%) female and 24 (48%) males. Results. We discovered greater blood IgE levels in AR patients compared to controls, although there was no statistically significant difference. (p = 0.455), but there was no significant difference for IL-4. (p = 0.91) We found no substantial differences in IL-5 serum levels among AR patients and control persons. The serum levels of IL-13 in.the control group were lower compared to the group of patients with IAR (p = 0.296). Conclusion: - Despite large differences in the amounts for There was no significant difference in the cytokines evaluated in our groups. differences are seen. This, we assume, is due to the small number of participants in each group. More research should be carried out. To demonstrate the function of IL-4, IL-5, IL-13, and IgE in the genesis and severity of sickness. [ABSTRACT FROM AUTHOR]

A synaptic cleft is one of the main cell structures providing a transduction of the exciting impulse between neurons. It is formed by a combination of three types of the membranes. One of them belongs to the neuron injecting a neuromediator (pre-synapse). Another one is forming by the neuron accepting a neuromediator's signal through receptors (post-synapse). Finally, the space between these membranes is partially surrounded by the astrocyte's membranes. The last one provides a re-uptake of the mediator out of the synapse. A free space among astrocytes part of the cleft makes it possible to accomplish a convectional diffusion of the mediator into the interstitial space of the tissue. In the present study a digital 3D reconstruction of a synaptic cleft has been made by the example of a glutamate/glycine synapse. The initial design of the space is made using geometrical primitives such as ellipses and cylinders. Further replacement of the obtained structure to the 3D objects and the consequence of Boolean operations form a localized 3D structure with explicit pre-synapse, post-synapse and astrocytes membranes. The final digital reconstruction of the synapse is a subject for further mesh's application, and it is suitable for a numerical estimation of both a laminar interstitial flow and a diffusion of both exciting and inhibiting mediators in a nervous parenchyma. [ABSTRACT FROM AUTHOR]

Photovoltaic modules comprising n-type silicon solar cells can be affected by the so-called polarization type of the PID-effect (PID-p). In this work, the PID-p behavior of our Q.ANTUM NEO n-type solar cell structure with passivating rear-side contact was investigated. The cells and modules were exposed to worst-case conditions under field and laboratory environments and were found to be PID-p resistant. It could be shown that only in case of artificial laboratory test conditions using high electric potential or current injection at elevated temperature, the investigated cell structure can be affected by PID-p with a power loss of about 25 %rel.. We show that under realistic field conditions, a power degradation due to PID-p will not occur. This is due to the fact that even a low light irradiation for short time was found to prevent PID-p and even recover the cells that were previously degraded by PID-p under artificial lab conditions. [ABSTRACT FROM AUTHOR]

Photovoltaic modules comprising n-type silicon solar cells can be affected by the so-called polarization type of the PID-effect (PID-p). In this work, the PID-p behavior of our Q.ANTUM NEO n-type solar cell structure with passivating rear-side contact was investigated. The cells and modules were exposed to worst-case conditions under field and laboratory environments and were found to be PID-p resistant. It could be shown that only in case of artificial laboratory test conditions using high electric potential or current injection at elevated temperature, the investigated cell structure can be affected by PID-p with a power loss of about 25 %rel.. We show that under realistic field conditions, a power degradation due to PID-p will not occur. This is due to the fact that even a low light irradiation for short time was found to prevent PID-p and even recover the cells that were previously degraded by PID-p under artificial lab conditions. [ABSTRACT FROM AUTHOR]

Due to high densities of energy, power, and remarkable operational efficiency of Li-on battery when in contrast to Lead-acid batteries and nickel-cadmium batteries are examples of other types of batteries. Vehicles, electronics, aircraft, and other industries are all interested in lithium-ion batteries right now. However, some critical variables, such as performance degradation under extreme driving circumstances due to temperature difference in the lithium-ion cell, limit its usefulness. As a result, it's important to decide the optimal course of action based on the consequences of heat generation on various lithium-ion cell components. This paper looked at how heat is generated and how it affects each component of a li-ion battery. An analysis of different heat-controlling systems employing various design structures in numerous techniques of cooling such as liquid convection, phase transition material, air Convection and a combination of these techniques are used. Finally, utilizing a variety of design frameworks, a summary is created [ABSTRACT FROM AUTHOR]

The metamaterial is an artificial material that consists of a periodic unit cell. That can tailor electromagnetic behavior. Metal material is used as a unit cell structure in this work. Cross-shaped was designed as a unit cell on this work. Four cases with different unit cell conductivity were considered in this work: 143 S/m, 762 S/m, 1,381 S/m, and 2,000 S/m. The scattering parameter was yield different results for every case. Low conductivity yields weak resonance performance. The unit cell's conductivity would adjust the metamaterial electrical properties; thus, the scattering parameter produces different results due to the material's electrical properties. [ABSTRACT FROM AUTHOR]

The main goal of the research was to study the possibilities of formalizing the structure of cellular concrete and the formation of a universal model of cellular concrete, on the basis of which it would be possible to obtain analytical dependencies. A universal model for studying and predicting the properties of cellular materials (in particular, foam- and gas aerated concrete) was created taking into account the existing modeling experience and was based on the use of the principles of constructing gas-structural elements for materials with spherical porosity. Using a universal model, the dependences of the connecting characteristics of structural elements with the compressive strength, thermal conductivity and moisture content of aerated concrete were obtained. The possibility of predicting the properties of aerated concrete under operating conditions is considered. The study of the properties of aerated concrete in the range of average densities of 100...400 kg/m3, corresponding to the interval adopted for heat-insulating aerated concrete, showed a good convergence of the results [ABSTRACT FROM AUTHOR]

Models of molecules transport through diffusion offer an important insight into the description of microscopic phenomena in nature. In the research, we focused on some models of chemoreception, from the perfect spherical absorbent, the use of Weber's disk, and the development of Berg and Purcell approach, to Zwanzig and Szabo generalized solution where interference effect and partially absorbing receptors are considered. Afterwards, we extrapolate Dudko's solution using a dimensional comparison for the diffusion current constant to receptors of arbitrary shape on a spherical cell, and contrast the absorption effectiveness on circular and elliptical chemoreceptors, using as reference the perfect spherical absorbent. During this process we looked to an important property related with the structure of chemoreceptors, their geometry. Is there a preferential setting that allows more particles to be absorbed in an ever smaller area? We found that the elliptical geometry offers a plausible model in cellular anatomy, a result that could explain the structure variation on chemoreceptors and the observed physiological changes on cells. [ABSTRACT FROM AUTHOR]

Calculations of the interaction of a cellular detonation wave with an inert porous filter are carried out. The realized detonation modes are revealed: propagation of attenuated cellular detonation wave and detonation failure with destruction of the cellular structure. The critical volume concentrations of particles in filter with diameters of 50, 100, and 200 µm, leading to detonation failure, are determined. [ABSTRACT FROM AUTHOR]

Numerical simulations of a detonation wave propagation in plane, rectangular and circular channels are performed and the formation of cellular structure is studied. A comparison of a detonation wave instability development in various channels is made. All numerical simulations are performed with an in-house numerical code on hybrid supercomputers. The code is written in C++ with the use of MPI, OpenMP and CUDA parallel technologies. AFRL chemical reaction mechanism for description of ethylene/oxygen/nitrogen mixture combustion is considered. [ABSTRACT FROM AUTHOR]

This article presents a frequency selective Surface (FSS) with stop band characteristics (transmission coefficient <- 10dB) for the 'S' (1.8 GHz-4 GHz.) and the 'X' (8 GHz-12 GHz) band. The proposed FSS has a square miniaturized unit cell structure with optimized dimensions of 0.147λ0 ×0.147λ0 ×0.0185λ0 where λ0 stands for free space wavelength at lower resonance frequency. This structure has fan shaped design enclosed by outer square loop structure of copper deposited on a commercially available FR4 substrate (εr = 4.4). The proposed structure also achieved miniaturization of 98% in size when it judges against the conventional structure of same resonance frequency. The proposed FSS designing, and simulation is carried out using CST MWS V'16 with unit cell boundaries and flout ports conditions. The prototype of the proposed FSS is fabricated and tested using Agilent's E 5063A, a two-port vector network analyzer and two horn antennas with a calibrated gain of 12dBi each (operating from 20 KHz to 20 GHz). The measured transmission parameters of the FSS that match well with the simulated ones allow its practical applicability for filtering out unwanted signals also used for protecting S and X communication frequency band applications. [ABSTRACT FROM AUTHOR]

The paper describes the results of the search for significant indices of chemiluminescent kinetics adequately reflecting the functional activity of bulls' blood cells. The analysis of the parameters of the model integral chemiluminescence curve was carried out to identify the proportion of participation of cellular and enzyme structures. Age-related dynamics showed a decrease in the level of antioxidant systems action. [ABSTRACT FROM AUTHOR]

The Subscriber Identity Module (SIM) card technology has been evolving in size and features over the years. The end-users identify a SIM card. It acts as a means of identifying devices onto a specific network. Embedded-SIM cards with remote provisioning capability can be proved to be a very efficient solution. They would add new features aiming towards improving the scalability of the Internet of Things (IoT) applications. The growing rate of Machine-to-Machine Communication (M2M) is witnessing challenges with the traditional SIM card technology. The advancements in applications and the need for faster data speeds and access require efficient mobility solutions. This study will help us understand the traditional cellular network structure, SIM card technology, and how the possible future scenarios in Machine to Machine (M2M) Communication would be changed by upcoming ESIM technology. This study would focus on the technical and business advancements, benefits, and challenges involved in adopting ESIM technology. [ABSTRACT FROM AUTHOR]

This work reports on the application of the differential junction photovoltage (diff-JPV) technique to characterize conducting layers at the emitter side of silicon heterojunction (HJT) cells structures by measuring their sheet resistance (Rsh). The diff-JPV measuring principle developed for homojunction emitters can be directly adopted for HJT cell structures to accurately determine Rsh of the transparent conductive oxide (TCO) layer at the emitter side. This is the first application of diff-JPV for non-silicon layers and heterojunctions. Furthermore, the result of this simple and rapid measurement is not influenced by the resistivity of the substrate wafer, and exhibits excellent correlation to optimized four-point-probe measurement. The unique feature of the diff-JPV technique is its capability to characterize emitter type layers even with very large sheet resistance, which is hardy accessible by other contactless techniques. It was found that performing the diff- JPV measurement on wafers after the PE-CVD process to deposit the hydrogenated amorphous Si layer stack, the resulted Rsh values lie in the 80 – 240 kΩ/sq. range. The dependence of the sheet resistance on the substrate doping indicates that the measurement is related to the inversion layer formed under the emitter amorphous silicon layer stack. Since such sensitive detection and characterization of the inversion layers cannot be accomplished by other techniques, diff-JPV can be an important method for the further optimization of heterojunction interfaces. [ABSTRACT FROM AUTHOR]

The problem of the initial packing of particles arising in the modelling of dry snow by the Discrete Element Method (DEM) is investigated. A formal method based on the periodic cellular mesoscale discretisation concept was suggested for dry snow consisting of a quasi-periodic ice skeleton and porous volume. The volume of the ice skeleton is shaped on a mesoscale by extracting the quasi-periodic structure of the pores, and its volume is fulfilled by the dense composition of initially bonded spherical particles on a micro scale. The cellular structure containing the cubic cell with inscribed spherical pores is considered to demonstrate the method. A wide range of snow densities ranging from 500 down to 100 kg/m3 is obtained by reducing the cell size and increasing the sphere pores. The experimentally obtained density-elasticity relationship is reconstructed by DEM simulation of the uniaxial unconfined compression test. [ABSTRACT FROM AUTHOR]

This work introduces a brand-new cells structure for multilevel converters based on the construction of a Flying Capacitor (FC). To make Switching pulses that are acceptable, the suggested architecture uses the (phase-shifted carrier pulse width modulation) PSC-PWM concept with adjusted modulation pulses. The modulation strategy is described, as well as all conceivable switching states. Waveforms are used to demonstrate the implementation of the proposed PWM approach. Different performance metrics are compared with alternative FC multicell (FCM) architectures to emphasise the benefits of the proposed structure. A four-cell, 17-level QFCM converter explains how the QFCM (QUADRUPLE FLYING CAPACITOR MULTICELL) works. From a variety of perspectives, the suggested structure outperforms other FCM-based designs. It does it by reducing the amount of high frequency switches and flying capacitors while also improving the quality of the output voltage. [ABSTRACT FROM AUTHOR]

Structural features of austenitic steel 316L and nickel alloy Ni-11%, Cr-5%, Co-6%, Al-3%, Ti-4%, Mo-5%, W-0.16%, C-0.02%, B (ZhS6K-VI) manufactured by laser powder bed fusion (L-PBF) were studied in this work. Alloys structures were formed under ultrafast cooling rates from the melt (105–107 K/s) and subsequent thermal cycling during re-melting of materials adjacent regions. It is known that such cooling conditions are nonequilibrium and can result in formation of nonequilibrium structures in alloys. The paper describes the features of such structures and some structural features for different alloys are considered: hierarchical structure, consisting of grains and subgrains; inhomogeneity of the distribution of alloying elements, accumulated at cell boundaries or secondary phases precipitation; high dislocations density with the cellular structure similar to those after plastic deformation; high macro stresses initiated cracking, and crystallographic texture resulted in anisotropy of mechanical properties. [ABSTRACT FROM AUTHOR]

The aim of this study are exhibiting visual observation result of 316L cellular structures and comparing mechanical properties among them which had been manufactured by selective laser melting (SLM). Some pre-defined cellular structures including cubic primitive (C), face center cubic (FCC), body center cubic (BCC) and hexagonal close packed (HCP) were designed with 0.5-1mm strut's diameter then applied to tensile test specimen shapes. These designs were generated to three dimensional object using SLM. Visual observations were performed to investigate these resulted objects. Mechanical properties were measured using tensile test to get their strength and modulus young. The result shows some struts size was not completely uniform. The FCC has the highest strength and modulus young with 105.4 MPa and 14110 MPa respectively. The HCP lattice exhibits the widest area of plasticity. The BCC strength and stiffness are almost similar to the HCP with lower plastic deformation area. The cubic has the lowest strength among them. In conclusion, each lattice structure, successfully fabricated by SLM, had specific tensile behavior. [ABSTRACT FROM AUTHOR]

In this work the Homotopy perturbation method (HPM) has been implemented in order to provide approximate analytical solutions to linear initial value problems for HIV infection model. The HPM approach allows unknown parameters to be defined by a few iteration steps for the obtained series solution. The model describes the number of unknown immune cells and the viral load in HIV-infected patients due to the uncertainty of the immune system. The immune cell components of the body are the cytotoxic T-lymphocytes (CTLs) and the CD4+T-cells. This stud measured the changes in body immune status and viral loads in three patient groups with high, medium, and low immune systems. The HPM method was slightly modified by using the established attributes of the fuzzy set's theory. Some plots and analysis are generated to show how reliable and simple the proposed method. The results are presented, and few terms are adequate to achieve an accurate approximation solution. [ABSTRACT FROM AUTHOR]

Lightweight concrete structure possessing either controllable mechanical characteristics or porous architecture like a triply periodic minimal surface (TPMS) blocks is the most engineering applications in construction industry. In this work, three types of 50 percent fraction-volume cellular structures, that are a hybrid design between Cubic block and Primitive-TPMS cell, Lattice and Gyroid-TPMS cell, are manufactured by 3D printed Polylactic Acid (PLA) formworks. The structures's mechanical characteristics are then evaluated by subjecting to uniaxial compression tests. Finite element (FE) method was employed to anticipate the stress-strain curves, stress distributions, and failure patterns of three chosen blocks. The numerical simulation outcomes are validated by the uniaxial compressive experiment tests. A quite consistent results between the practice and numerical model indicated that the Primitive structure yields the strongest strength of compression capacity among all. [ABSTRACT FROM AUTHOR]

Investigation of the effects of ionizing radiation on cells of the central nervous system is a challenging topic in modern radiation research, as well as treatment planning in radiation therapy and predicting the space radiation risk for the health of astronauts. In this work, we studied processes of degradation of dendritic branches and spines of mature neurons depending on the radiation dose of different particles using Monte Carlo simulations (Geant4). Microscopic energy and dose depositions, number of particle traversals, cell hits and the formation of molecular damages as a function of linear energy transfer were simulated. Based on these data dose-dependent survival of immature neurons in the subgranular zone of the rat hippocampus were estimated following irradiation. Our simulation results for protons and heavy ions are consistent with the experimental results. [ABSTRACT FROM AUTHOR]

A numerical simulation of a supersonic (M∞ = 7) flow around a cylinder with a front gas-permeable porous insert at a zero angle of attack was carried out using three-dimensional skeleton models of a highly porous cellular material made of non-intersecting hard spheres with a regular and chaotic arrangement of pores. A comparative analysis of these skeleton models with different spatial arrangement and pore size showed a weak influence of the structure of skeleton models on the resistance of a cylinder with a front gas-permeable insert. The computed data of the drag coefficient are compared with the results of tube experiments. [ABSTRACT FROM AUTHOR]

Based on the concave triangular negative Poisson's cell structure, a novel butterfly-like multicellular structure is proposed in this paper. The explicit dynamic finite element software LS-DYNA was used to establish the finite element models of axial impact at different concave angles, and the accuracy of the simulation model was verified. The effects of different concave angles on peak impact force, platform stress and specific energy absorption were studied. The results show that the novel butterfly-like multicellular structure has zero Poisson's ratio characteristics, and the change of the recessed angle has a greater impact on the dynamic performance of the impact. With the decrease of the indentation angle, the initial peak value decreases, the fluctuation of the plateau area weakens and becomes longer, and the energy absorption process becomes more stable. Through the reasonable design and optimization of the concave form, it can be applied to the energy absorption buffer effect under various working conditions. [ABSTRACT FROM AUTHOR]

In this work the role of transmission electron microscopy (TEM) in biology and pathology studies is emphasyzed. A overview on technical procedures is provided and their advantages or disadvantages, with particular attention to possible artifacts, are reported. The importance of the ultrastructural approach in cell and isolated organelle characterization, frequently correlated to functional and molecular analyses, is supported by specific images and by a cospicous number of references. Negative staining, a simple and rapid method, is also described and a number of examples from different types of viruses are illustrated. Cryo-EM is finally mentioned. It is illustrated by means of frozen ultrathin sections, compared to those from epon embedded conventional ones. Finally, freeze-fractured sample replicas are presented, both aimed at membrane detail highlighting and inner cell structure investigation. TEM, in its variety of applications, and in particular if integrated by molecular studies, is a very important tool in the study of life sciences and, in general for nanotechnology. [ABSTRACT FROM AUTHOR]

In this work, physical and mathematical models were formulated for predicting the effective acoustic properties of various shapes SAS cells in non-linear operation modes. Numerical studies have been carried out to assess the acoustic efficiency of single sound-absorbing structures cells of honeycomb and cone-like shapes in an interferometer with normal sound wave incidence in linear and non-linear operation modes. Verification of the developed mathematical models was carried out. According to the results of numerical experiments, the most efficient resonators were identified. [ABSTRACT FROM AUTHOR]

The peculiarities of ecological conditions determine different scenarios of adaptive changes in the immune and genetic status with the subsequent formation of eco-caused pathology. Purpose of the study: analysis of the peculiarities of the immunological and genetic status of the child population in the extreme conditions of the Arctic Circle of Russia under the combined impact of anthropogenic chemical and climatogeographic factors. Materials and methods . Immunological and genetic testing of 98 children (the territory of the Arctic of Russia), differing in the level of anthropogenic chemical load, was carried out. Methods of flow cytometry, real-time polymerase chain reaction and allergosorbent testing were used. Results. The carried out immunological and genetic examination of children living in extreme environmental conditions of the Arctic Circle of Russia revealed an imbalance in the cellular component of immunity, expressed in increased expression of activation markers CD95+ and CD25+, proteins - Bax, Bcl-2, p53 and the TNFR receptor responsible for apoptosis ( p <0.05). Changes in the humoral link of immunity are also observed - IgA deficiency in children, hyperproduction of specific IgE to nickel (p <0.05), IgG to copper, benz (a) pyrene, phenol. In relation to the control group, increased levels of the frequency of variant alleles of the following genes were established: CYP1A1 rs 1048943, GSTP 11695, EPHX1 rs 1051740, CLOCK 1801260, eNOS rs1799983, VEGF rs2010963; TP53 rs1042522. Conclusion. The data obtained indicate the stimulation of the apoptotic receptor activity of immunocompetent cells with the activation of cell death and the probable formation of immunodeficiency. The identified polymorphisms and their prevalence characterize genetic variants of the likelihood of developing disorders in children exposed to a combined exposure to extreme climatic and anthropogenic factors associated with detoxification processes of the first and second phases, adaptive disorders of temporal synchronism, multifactorially mediated vascular disorders, proliferative scenarios (autoimmunity, oncoproliferation). [ABSTRACT FROM AUTHOR]

We considered strength of an extended cell simulating the structure of a high-entropy crystal alloy сcontaining iron. Atoms of five chemical elements, including iron, are randomly distributed within the cell. Calculations of cell tensile strength were carried out by using a complex of quantum chemical programs ADF. It is shown that for any arrangement of atoms in the cell, its strength is always less than the strength of the cell consisting only of iron atoms. [ABSTRACT FROM AUTHOR]

A study on the use of track etched membranes (TM) based on the polyethylene terephthalate (PET), including those modified with cold plasma, followed by layering of prenatal stromal cell (PSC) culture on the material surface in vitro in the surgical treatment of a bullous keratopathy (BK) of the cornea has been conducted. The study was conducted on 16 Sylvilagus bachmani rabbits, which after BK modelling were divided into 4 groups: the 1st group was a control group of 4 animals (4 eyes); the 2nd group was a group of 4 animals (4 eyes) which were implanted by TM; the 3rd group was a group of 4 animals (4 eyes) which were implanted by TM with cells; the 4th group was a group of 4 animals (4 eyes) which were implanted by plasma modified TM with cells. TM was obtained by irradiating PET with 40Ar+8 ions and subsequent chemical etching. Eyes were enucleated for histological examination after 8 weeks from the start of the experiment. As a result of the research, it was found that the implantation of TM with a preliminary layering of human PSC promotes the growth of the fibroblast population in the cornea stroma and forming of the leukocyte (lymphocytic and eosinophilic-basophilic) infiltration compared with the implantation of TM without a cellular component. In addition the implantation of TM contributes to a twofold decrease in the induced by BK cornea edema. [ABSTRACT FROM AUTHOR]

Terrestrial gamma flash (TGF) and thunderstorm ground enhancements(TGE) phenomena are crucial for understanding of atmosphere breakdown and lightning generation physics. The initial theory was developed by Gurevich and included only runway breakdown description. It was later updated by Babich and Dwayer, but even updated models use a rather simplified field structure and do not fully explain observed quantities. The reactor like TGE (RL-TGE) model presented in this work assumes more complicated stochastic field structure and takes into account not only one cell runway breakdown, but the whole global field cellular structure in the thundercloud. It allows to describe a wide variety of TGF-like events and potentially fills the gap in thundercloud parameters previously unaccounted by other theories. [ABSTRACT FROM AUTHOR]

Currently, solar simulators demand component solar cells, also named isotypes, in order to equilibrate their spectrum and match the required norm. Each architecture of cell needs a specific set of isotypes and each one of them need calibration in order to assess the incident power coming from the solar simulator in its spectral range. In this article, pseudo-isotypes are proposed in order to ease the spectral balance of new architectures of multijunction solar cells (MJSC). Pseudo-isotypes are silicon and germanium photodiodes filtered with filters reproducing the cut-on and the cut-off of each MJSC subcell. The use of pseudo-isotypes requires the development of a simple and accurate calibration in order to obtain the constants associated with these references without sending it to a certified laboratory. An indoor calibration method is described and its accuracy is assessed. IV characteristics of 3J MJSC under a solar simulator are carried out with different sets of references: i) isotypes calibrated outdoor, ii) isotypes calibrated indoor, and iii) pseudo-isotypes calibrated indoor. [ABSTRACT FROM AUTHOR]

This paper provides an overview about the recently performed development of rigid polyurethane (PUR) foams on a cryogenic insulation for liquefied hydrogen (LH2) tanks application and gives information on the characterization test campaigns performed so far. Since this specific insulation is foreseen to be applied on inner surfaces of the propellant tanks it is called Inner Wetted Thermal Insulation (IWTI). The IWTI obtained by spraying method has been especially designed (with apparent core density 85 ± 2 kg/m³) for an optimum chemistry and cell structure morphology in order to achieve superior mechanical and thermal performance under these exceptional conditions. Studies of the foams` tension and compression properties at 295 and 77 K were carried out. The obtained safety coefficient of cryogenic insulation material reached 3.7. [ABSTRACT FROM AUTHOR]

Metamaterials are artificial materials assembly of structures of sub-wavelength dimensions, and are known to exhibit unusual properties that can be exploited for several purposes. In this paper, we report a novel planar design suitable for metamaterial applications. The structure yields very low transmittivity and negative refractive index at 1120nm. The computation is performed using Finite Element Method with the help of Comsol Multiphysics and MATLAB, and the refractive index is obtained using the S-parameters. [ABSTRACT FROM AUTHOR]

Fused Filament Fabrication (FFF), or 3D printing, of continuous fibre reinforced composites allows getting advanced materials (steered-fibres, dispersed stacking sequence laminates or functionally graded composites), as well as complex geometries (cellular structures or metamaterials). However, FFF presents several drawbacks, especially when large-projected area or high-fibre content composite parts are required. On the other side, stamp forming of organo-sheet thermoplastic composites is a cost-effective technology, but with severe geometric limitations. Combining both technologies, by over-3D printing on the organo-sheet, can be a promising approach to add the best of each of them. The effect of the organo-sheet temperature on the shear strength of the bonding interface is studied. The results show that strong bonding interface can be achieved when the correct substrate temperature is chosen. In fact, it is largely improved if the interface temperature is higher than the melting temperature of the substrate layer. [ABSTRACT FROM AUTHOR]

A computer based simulation of solar cell structure is performed to study the optimization of pn junction configuration for photovoltaic action. The fundamental aspects of photovoltaic action viz, absorption, separation collection, and their dependence on material properties and deatails of device structures is discussed. Using SCAPS 1D we have simulated the ideal pn junction and shown the effect of band offset and carrier densities on solar cell performance. The optimum configuration can be achieved by optimizing transport of carriers in pn junction under effect of field dependent recombination (tunneling) and density dependent recombination (SRH, Auger) mechanisms. [ABSTRACT FROM AUTHOR]

Solution processable organic solar cells have attracted significant interest in scientific community due to their easy processability, flexibility and eco friendly fabrication. In these organic solar cells structure, PEDOT:PSS layer has major importance as it used as hole transporting layer. In the present work, we have analyzed the effect of incorporation of silver nanoparticles (AgNPs) in PEDOT:PSS layer for P3HT:PCBM based organic solar cells. The presence of Ag nanoparticles in PEDOT:PSS film is confirmed by atomic force microscopy (AFM) images. It has been observed that PEDOT:PSS layer with AgNPs has ∼5.4% more transmittance than PEDOT:PSS layer in most of the visible region, which helps in reaching more light on active layer. Finally, solar cell with structure ITO/PEDOT:PSS:AgNPs/Al is fabricated and J-V characteristics are plotted under illumination. It is observed that there is a significant (∼10%) enhancement in short circuit current and slight increment in open circuit voltage with addition of AgNPs in PEDOT:PSS layer. The calculated value of power conversion efficiency (PCE) of fabricated device without AgNPs in PEDOT:PSS was 1.67%, which increased to 2.02% after addition of AgNPs in PEDOT:PSS layer. [ABSTRACT FROM AUTHOR]