Hard Component Research Articles

Phenomena of Absorption of Soft and Hard Components of Space Rays in the Atmosphere in Yerevan Conditions

The article examines the angular distribution of cosmic ray intensity and identifies the triads using two different empirical formulas for their distribution. The total absorption coefficient of soft and hard components was measured.

The finite element modeling of the impacting process of hard particles on pump components

Abstract Shield pumps which transport a variety of complex media are widely used in chemical industry, mineral industry, and other fields. However, the hard particles in the media erode the flow passage in the shield pump, seriously affecting the service life of the pump. Therefore, it is important to study the erosion process in the flow passage to extend the service life of the pump. This erosion process in the shield pump can be investigated by experiments, but it is difficult for the current experimental method to copy the real industrial service environment of impellers. For example, the environment temperature and speed range are found difficult to be reached by the current experimental method. Comparatively, the simulation by finite element method can overcome the above deficiency. In this article, the ANASYS software is used to simulate the erosion process in shield pump flow passage due to hard particles. Specifically, the structural static analysis module is used to build the model of thermal barrier coating components and hard particle components. Then the variation law of stress, strain, and material deformation of the flow passage components under concentrated force is obtained. Second, the extended finite element method is used to study the crack propagation caused by the erosion process. A linear elastic–linear softening constitutive model is established to simulate the stress variation during the crack propagation and material removal under the continuous erosion from hard particles. The proposed law regarding stress variation and crack propagation in the erosion process in this study contributes to theoretical support for damage detection and service life extension of shield pumps.

Surface hardness and corrosion behavior of laser surface-alloyed Ti6Al4V with copper

Laser surface alloying of Ti6Al4V with different Cu contents (6, 8, 13 and 17 wt%) was successfully achieved using a high-power diode laser. With a higher Cu content, the grain size of the laser surface-alloyed Ti6Al4V specimens became finer, with more intermetallic phases (IMPs) formed and the hardness increased up to 646 ± 18 HV0.2. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were conducted to study the corrosion behavior of the laser surface-alloyed specimens in a 0.9 wt% NaCl solution at 37 °C. It was found that the specimen alloyed with 6 wt% Cu showed the mild micro-galvanic effect between CuTi2 and α-Ti. The specimen with 17 wt% Cu had the highest content of IMPs and possessed the lowest corrosion resistance due to the most significant micro-galvanic effect between the IMPs (cathode) and the α-T / β-Ti matrix (anodes). With an appropriate Cu content, laser surface-alloyed Ti6Al4V can also act as hard and corrosion resistant components possessing a high anti-bacterial efficacy by virtue of Cu.

Cross-Border, Interoperable Cooperative Intelligent Transportation Systems: Could We Make Them Operational? [Editor’s Column

Aimed at increasing people’s mobility, the Cooperative Intelligent Transportation Systems (C-ITS) paradigm postulates that all modes of transport, and their means, are interconnected and their operations synchronized in time. This principle is also imposed on C-ITS infrastructures as well as services provided by C-ITS solutions. All of these inevitably require interconnectivity and interoperability among all C-ITS hard and soft components, products, and services. In return, such operational conditions make C-ITS components interdependable.

A Review on COVID Mortality Prediction with Machine Learning Methods

More than a year has passed since the report of the first case of coronavirus disorder 2019 (COVID), and increasing deaths hold to occur. Minimizing the time required for useful resource allocation and medical choice making, together with triage, desire of air flow modes and admission to the intensive care unit is essential. system learning strategies are acquiring an increasingly more sought-after role in predicting the outcome of COVID sufferers. in particular, the use of baseline gadget learning techniques is swiftly growing in COVID mortality prediction, in view that a mortality prediction model could unexpectedly and effectively help medical choice-making for COVID sufferers at approaching threat of demise. latest research reviewed predictive fashions for SARS-CoV-2 prognosis, severity, period of sanatorium live, extensive care unit admission or mechanical ventilation modes results; however, systematic opinions centered on prediction of COVID mortality outcome with machine gaining knowledge of methods are missing within the literature. the present evaluation appeared into the studies that carried out gadget mastering, inclusive of deep studying, methods in COVID mortality prediction as a result trying to gift the prevailing posted literature and to offer feasible causes of the pleasant effects that the research received. The have a look at also mentioned hard components of cutting-edge research, supply in guidelines for destiny developments.

Classified Transformation from Proletariat to Precariat

One of the strictest realities of social life is class structure. Therefore, Karl Marx based his analysis of social structure on the labour form of the class that constantly produces itself and its opponent. He speaks of a class structure based on material labour determined by means of production and production relations. This class is known as the proletariat. However, in this cycle, which progresses continuously on the axis of change and transformation, the class has become flexible and labour has moved away from its material state. In Marx's words, the solid has evaporated. In other words, the new social class that has adapted to the flexible life and labour process and was stuck between the continuous work and life changes is the precariat. The basis of the precariat class is not only the proletarian workers and their labour, but also their identity, colour, religious affiliations. Those who are outside the wall of equality aim to achieve the digital era and somehow their whole life has been cognitive, and they are living new fluid human's states resulting in alienation from their labour. In this study, the class transformation will be emphasized that Marx went through while evolving into precariat in the informatics society of the proletariat, which he put forward for the industrial society. The class transformation in question will be discussed in the context of Hard and Negri's class components and Guy Standing's precariat concept. This study will include the fluid course of class transformation. In addition to these, this study is important as it aims to analyze the contexts of human life, post-human and trans-human processes by including digitalization.

Nature of particles azimuthal anisotropy at low and high transverse momenta in ultrarelativistic A + A collisions

LHC data on the correlations of the elliptic flow v 2 of particles at low and high transverse momenta p T from Pb+Pb collisions at center-of-mass energy per nucleon pair TeV are analyzed in the framework of the HYDJET++ model. This model includes soft and hard components which allows to describe the region of both low and high transverse momenta. The origin of v 2 values in different p T regions is investigated at different centralities. It is shown that the experimentally observed correlations between v 2 at low and high p T in peripheral lead-lead collisions is due to correlation of particles in jets.

Relationship between Gel Mesh and Particle Size in Determining Nanoparticle Diffusion in Hydrogel Nanocomposites.

The diffusion of poly(ethylene glycol) methyl ether thiol (PEGSH)-functionalized gold nanoparticles (NPs) was measured in polyacrylamide gels with various cross-linking densities. The molecular weight of the PEGSH ligand and particle core size were both varied to yield particles with hydrodynamic diameters ranging from 7 to 21 nm. The gel mesh size was varied from approximately 36 to 60 nm by controlling the cross-linking density of the gel. Because high-molecular-weight ligands are expected to yield more compressible particles, we expected the diffusion constants of the NPs to depend on their hard/soft ratios (where the hard component of the particle consists of the particle core and the soft component of the particle consists of the ligand shell). However, our measurements revealed that NP diffusion coefficients resulted primarily from changes in the overall hydrodynamic diameter and not the ratio of particle core size to ligand size. Across all particles and gels, we found that the diffusion coefficient was well predicted by the confinement ratio calculated from the diameter of the particle and an estimate of the gel mesh size obtained from the elastic blob model and was well described using a hopping model for nanoparticle diffusion. These results suggest that the elastic blob model provides a reasonable estimate of the mesh size that particles "see" as they diffuse through the gel. This work brings new insights into the factors that dictate how NPs move through polymer gels and will inform the development of hydrogel nanocomposites for applications such as drug delivery in heterogeneous, viscoelastic biological materials.

Removal Mechanism of Abrasive Jet Polishing with a Novel Nozzle

In view of the high-precision and low-damage requirements for surface polishing of hard and brittle components, an abrasive jet polishing process using a novel nozzle with specifically designed shroud was proposed. The removal mechanism of abrasive jet polishing was investigated by simulating the jet flow in the interaction area of the nozzle shroud and workpiece. The simulation results indicate that the velocity of the abrasive jet increases greatly by the shroud and the direction of the jet is aligned almost parallel to the workpiece surface. With such a design, the normal force of the abrasive jet is minimized to reduce the impact damage of the workpiece surface. Further, the stabilized abrasive jet insures a smooth machining. The machining experiments were performed on the quartz glass component, a typical hard and brittle material. The results of the shrouded abrasive jet polishing experiments show that the material removal mainly relied on the shearing and scratching of the workpiece surface rather than the mechanical shock impacts, which is consistent with the simulation findings.

Bacteriological Analysis of Water used in Abattoirs within Ilorin metropolis, Kwara State, Nigeria

Water that is used in the abattoir for meat processing, cleaning procedures, drinking and other activities must meet international standard for potable water. It must not contain chemicals, hard physical components or microorganisms in amounts high enough to cause hazards to health. The bacteriological status and risk posed by the water used in four government owned abattoirs in Ilorin, Kwara State, Nigeria, were evaluated in this study. The bacteriological examination of samples of water from available sources in abattoirs in the study areas were carried out to determine their suitability for use and potability. Twenty-six samples were collected both before (BA) and during (DA) abattoir activities. The pour plate technique was used to ascertain the Total Viable Bacterial Count (TVC) of collected water samples. The Estimated Number of Coliform Count (ECC) was determined using MacConkey broth. The values of TVC and ECC for all the samples ranged from 2x106 to 4.8x107 CFU/mL This exceeded the 1x102 CFU/mL limit recommended by WHO for potable water. A total of 52 isolates belonging to 8 bacteria species were identified; 2 Acinetobacter spp. (3.8%), 14 Bacillus spp. (26.4%), 3 Citrobacter spp. (5.7%), 3 Enterobacter spp. (5.7%), 12 Salmonella spp. (22.6%), 4 Shigella spp. (7.6%), 9 Staphylococcus spp. (17%) and 6 Proteus spp. (11.2%) were isolated from the water samples. Results showed that water samples from the study areas had high bacterial load, thus posing high public health and food safety risks especially to the public that consume on meat processed with the water from these abattoirs. Governmental/non-governmental organizations and spirited individuals should urgently address the issue of provision of adequate and safe water for abattoir activities in addition to providing facilities for water treatment so as to safeguard the health of the populace. Consumers should properly wash meat and meats products after purchase, boiling, steaming, frying and proper cooking of meat after purchase and before consumption are highly recommended.

Constrained abrasive jet polishing with a tangentially aligned nozzle shroud

In order to improve surface polishing quality and efficiency for hard and brittle components, a novel nozzle with specifically designed shroud was proposed for an abrasive jet polishing process. The removal mechanism of the abrasive jet under such a nozzle was investigated by simulating the jet flow in the interaction area of the nozzle shroud and workpiece. The simulation results show that the speed of the abrasive jet increases greatly by the shroud and the direction of the jet is aligned near parallel to the workpiece surface to minimize impact damage to workpiece surface. The constrained abrasive jet polishing (CAJP) experiments were conducted on the quartz glass component, a typical hard and brittle material, showing that the material removal mainly relied on the shearing and scratching of the workpiece surface rather than the mechanical shock impacts, which is consistent with the simulation findings.

Parametric Optimization of Material Removal Rate of EDM (AISI-4147) by using Taguchi Approach

Electric discharge machine is a non-conventional machining. In which there is no contact between tool and work piece. By EDM process machining of hard material components that are difficult to machine such as heat treated tool steels, ceramics, composites, carbides, heat resistance steel which are used in die and mould producing industries, aero space and nuclear industries. EDM is a non-contact type technique of material removal and in this spark is used to remove the material from the work piece. Since the EDM is an attractive means of making tool and dies with high accuracy in dimension and surface finish quality of micro scale parts. The present experimental research studies the process parameters that are influencing the machining concert and its productivity. A collective approach is used for the optimization in parameters and performance characteristics which are based on Taguchi method. The experiments are based on Taguchi‟s L9 orthogonal array. The reaction graph and reaction table of each near of machining constraints are took from Taguchi method to select the optimum levels of machining factors. In the work, the machining parameters for thesis are current, pulse on time and pulse off time, which are optimized for minimum tool wear rate (TWR), maximum material removal rate (MRR) and minimum surface roughness during electro discharge machining of AISI 4147. Analysis of Variance is also used to find out variable affecting the various responses mentioned above.

An XMM-Newton EPIC X-Ray View of the Symbiotic Star R Aquarii

Abstract We present the analysis of archival XMM-Newton European Photon Imaging Camera (EPIC) X-ray observations of the symbiotic star R Aquarii. We used the Extended Source Analysis Software package to disclose diffuse soft X-ray emission extending up to 2.′2 (≈0.27 pc) from this binary system. The depth of these XMM-Newton EPIC observations reveals in unprecedented detail the spatial distribution of this diffuse emission, with a bipolar morphology spatially correlated with the optical nebula. The extended X-ray emission shares the same dominant soft X-ray-emitting temperature as the clumps in the jet-like feature resolved by Chandra in the vicinity of the binary system. The harder component in the jet might suggest that the gas cools down; however, the possible presence of nonthermal emission produced by the presence of a magnetic field collimating the mass ejection cannot be discarded. We propose that the ongoing precessing jet creates bipolar cavities filled with X-ray-emitting hot gas that feeds the more extended X-ray bubble as they get disrupted. These EPIC observations demonstrate that the jet feedback mechanism produced by an accreting disk around an evolved, low-mass star can blow hot bubbles, similar to those produced by jets arising from the nuclei of active galaxies.

Cosmic ray production in superbubbles

ABSTRACT We compute the production of cosmic rays (CRs) in the dynamical superbubble (SB) produced by a cluster of massive stars. Stellar winds, supernova remnants, and turbulence are found to accelerate particles so efficiently that the non-linear feedback of the particles must be taken into account in order to ensure that the energy balance is not violated. High-energy particles do not scatter efficiently on the turbulence and escape quickly after each supernova explosion, which makes both their intensity inside the bubble and injection in the interstellar medium intermittent. On the other hand, the stochastic acceleration of low-energy particles hardens the spectra at GeV energies. Because CRs damp the turbulence cascade, this hardening is less pronounced when non-linearities are taken into account. Nevertheless, spectra with hard components extending up to 1–10 GeV and normalized to an energy density of 1–100 eV cm−3 are found to be typical signatures of CRs produced in SBs. Efficient shock reacceleration within compact clusters is further shown to produce hard, slightly concave spectra, while the presence of a magnetized shell is shown to enhance the confinement of CRs in the bubble and therefore the collective plasma effects acting on them. We eventually estimate the overall contribution of SBs to the Galactic CR content and show typical gamma-ray spectra expected from hadronic interactions in SB shells. In both cases, a qualitative agreement with observations is obtained.

АНАЛИЗ ЗУБНЫХ ПАСТ, ПРИМЕНЯЕМЫХ В КАЧЕСТВЕ ОСНОВНОГО СРЕДСТВА ИНДИВИДУАЛЬНОЙ ГИГИЕНЫ ПОЛОСТИ РТА. ОБЗОР ЛИТЕРАТУРЫ

Subject. A literature was reviewed on the relevant subject dedicated to the prevention of dental diseases – the study of the modern market of toothpastes used as the basic oral care products. 
 Methodology. The data of special literature were studied using scientific tracking library databases: Pub Med, Elibrary, Cochrane. Literature was analysed using 55 sources.
 Results. On the modern market, there is a wide range of toothpastes with various properties due to active ingredients they are composed of. Despite the wide and varied range of these oral care products, there is no officially recognized classification of this product. The children's toothpastes should meet the following requirements: be neutral, have cleansing and polishing properties, have a good smell, flavour and appearance, cooling and disinfecting effects, be harmless and have a therapeutic and prophylactic effect. In the special literature, there are many studies on the use of toothpastes in case of high caries severity. The modern direction of therapeutic and prophylactic pastes is the inclusion of various enzymes in their composition. These components are able to increase the cleansing effect of hygiene products due to the lysis of the organic matrix of soft and hard components of plaque, bacteriostatic or indirect bactericidal effects on the biocenosis of the mouth, including the products of microorganisms.
 Conclusions. On the modern market, there is a huge range of toothpastes with various active ingredients effecting the causes of oral diseases, but there is still no toothpaste which would be safe to accidentally swallow during long-term use, which is one of the main reasons for development of individual oral health programs for patients with aggravated somatic status, as well as for those who have neuropsychiatric disorders. Therefore, the question of the absolutely safe toothpastes as the basic oral care products remains open.

Quantitative Analysis of Growth Factors From Cancellous Bone Graft Collected With a Reamer-Irrigator-Aspirator System From Native Long Bones Versus Previously Reamed Long Bones.

Collection of bone graft with the Reamer-Irrigator-Aspirator (RIA) system has become common practice across the field of orthopaedic surgery. While RIA bone graft is typically obtained from native long bones, grafting material can likewise be harvested from long bones that have previously undergone the placement and removal of an intramedullary nail, a process termed re-reamed RIA (RRR). The purpose of this study was to evaluate the total protein and growth factor concentrations present in native-RIA (NR) compared with RRR samples. NR and RRR bone grafts were collected intraoperatively with the RIA system and processed to evaluate both the aqueous and the hard tissue components. Total protein concentration and specific growth factors were analyzed using standard bicinchoninic acid and multiplex assays, respectively. Analyte levels were then normalized to the total amount of protein detected. Total protein levels were comparable between NR and RRR samples for both the aqueous filtrate and the hard tissue samples. When normalized, while levels of bone morphogenic protein-2 and vascular endothelial growth factor were comparable in the hard tissue component, the aqueous filtrate from the RRR sample was found to have elevated levels of growth factors, with bone morphogenic protein-2 reaching statistical significance. This study demonstrates that ample protein is found within both NR and RRR samples, with comparable or elevated levels of osteogenic growth factors found within RRR samples. Future, larger, prospective studies will be required to evaluate the osteogenic potential and clinical efficacy of NR and RRR cancellous bone grafts to validate their equivalency.

TeV and keV–MeV Excesses as Probes for Hadronic Process in BL Lacertaes

Abstract A hard TeV γ-ray component excess over the single-zone leptonic model prediction (TeV excess) is observed in the spectral energy distributions (SEDs) of some BL Lacs. Its origin is uncertain. We revisit this issue with four BL Lacs (1ES 0229+200, 1ES 0347–121, 1ES 1101–232, and H2356–309), in which the TeV excess is detected in their intrinsic SEDs. We represent their SEDs with a single-zone leptohadronic model, where radiations of the electrons and protons as well as the cascade electrons produced by the γγ and pγ interactions within their jets are considered. We show that the observed SEDs below the GeV gamma-ray band are attributed to the synchrotron radiations and self-Compton process of the primary electrons, and the TeV excess is explained with the γ-ray emission from the pγ process via the π 0 decay. The cascade emission of the electrons produced via the γγ and pγ interactions results in a keV–MeV excess in the SEDs, illustrated as a bump or plateau. This extra photon field enhances the production of TeV photons from the p γ process, resulting in a reduction of the proton power by about one order of magnitude. However, the derived powers are still 3–4 orders of magnitude larger than the Eddington limit, being challenged by the current black hole accretion physics. Applying our model to Mrk 421, we propose that synergic observations with current and upcoming TeV and keV–MeV telescopes for its tentative TeV and MeV excesses can give insights to the hadronic process in its jet.

Recent Advances in Wearable Optical Sensor Automation Powered by Battery versus Skin-like Battery-Free Devices for Personal Healthcare-A Review.

Currently, old-style personal Medicare techniques rely mostly on traditional methods, such as cumbersome tools and complicated processes, which can be time consuming and inconvenient in some circumstances. Furthermore, such old methods need the use of heavy equipment, blood draws, and traditional bench-top testing procedures. Invasive ways of acquiring test samples can potentially cause patient discomfort and anguish. Wearable sensors, on the other hand, may be attached to numerous body areas to capture diverse biochemical and physiological characteristics as a developing analytical tool. Physical, chemical, and biological data transferred via the skin are used to monitor health in various circumstances. Wearable sensors can assess the aberrant conditions of the physical or chemical components of the human body in real time, exposing the body state in time, thanks to unintrusive sampling and high accuracy. Most commercially available wearable gadgets are mechanically hard components attached to bands and worn on the wrist, with form factors ultimately constrained by the size and weight of the batteries required for the power supply. Basic physiological signals comprise a lot of health-related data. The estimation of critical physiological characteristics, such as pulse inconstancy or variability using photoplethysmography (PPG) and oxygen saturation in arterial blood using pulse oximetry, is possible by utilizing an analysis of the pulsatile component of the bloodstream. Wearable gadgets with “skin-like” qualities are a new type of automation that is only starting to make its way out of research labs and into pre-commercial prototypes. Flexible skin-like sensing devices have accomplished several functionalities previously inaccessible for typical sensing devices due to their deformability, lightness, portability, and flexibility. In this paper, we studied the recent advancement in battery-powered wearable sensors established on optical phenomena and skin-like battery-free sensors, which brings a breakthrough in wearable sensing automation.

Nanocomposites made from thermoplastic linear poly(urethane-siloxane) and organoclay: Composition impact on the properties

Thermoplastic poly(urethane-siloxane)/organoclay nanocomposites (TPU NCs) with different hard segment content (20?55 wt. %) were prepared by in situ polymerization in the presence of organically modified montmorillonite as a nanofiller (Cloisite 30B; 1 wt. %). Hydroxyl-terminated ethoxypropyl- poly(dimethylsiloxane) was used as soft segment, while 4,4'-methylenediphenyl diisocyanate and 1,4-butanediol were the hard segment components. The study of the influence of the hard segment content on the functional properties of TPU NCs was performed by Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), dynamic mechanical thermal analyses (DMTA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), water contact angle and water absorption tests. The results revealed that TPU NCs with the increasing hard segment content exhibit higher values of degree of microphase separation, melting temperature of the hard segments, degree of crystallinity, storage modulus (except for TPU NC-55), but lower thermal stability and hydrophobicity. TPU NC films were hydrophobic and their free surface energy was in the range from 17.7 to 24.9 mJ m-2. This work highlights how the composition of TPU NCs would affect their functional properties and provide an additional composition intended for designing advanced TPU NC materials for special biomedical applications.

Influence of cryogenic treatment on tool life, flank wear and surface roughness for machining nickel based super alloy-Haynes 282

With the growing need for hard alloys components and metals, cryogenic machining has gained popularity and Cryogenic machining is seen as a more environmentally friendly feasible and option to flood cooling. This experimentation describes a long-term cryogenic machining solution that takes into account not just traditional machining performance, but also total sustainability performance in each of the three sustainability elements: economy, environment, and society. Haynes 282 alloy was machined under three conditions such as flood lubrication, cryogenic condition and dry condition. It was observed that cryogenic condition was useful for achieving better surface finish of 0.632 µm. In addition to this, less cutting force was required for all cutting speed under cryogenic machining which consumes less power consumption. Tool life decreases with an increase in cutting speed. Maximum tool life of 41.3 min was observed for cryogenic cutting condition at 125 m/min. Higher Flank wear was noticed for flood lubrication condition than cryogenic condition.