bluuebunny/crossref_metadata_2025_split huggingface dataset:
Express ultra-jet diagnostics of defect resistance for surface layer of a material
Authors: Barzov A A , Galinovskiy A L , Prokhorova M A 
Published: February 2021

Abstract
In the manufacture of products of modern technology, such technologies of waterjet processing as water jet cutting are successfully used for cutting materials. However, the physical and energy basis of ultrajet technology predetermines a much broader scope of its practical applications. Most of modern technical products are made of composite materials. Moreover, some of them were obtained by innovative methods, for instance, selective laser fusion, which complicates their diagnostics. This article proposes an innovative method for determining a new informative parameter characterizing the defect resistance of various materials. This technique is based on the process of hydro-erosive destruction in the process of ultrajet exposure to a high-energy jet on the surface of the material being diagnosed. Ultra-jet diagnostics (UJD) is based on the analysis of the dependence of the characteristics of local hydro-erosion of the diagnosed area of the surface of the object under analysis (OA) on the parameters of its quality. Surface quality parameters include physical and mechanical properties (PMP) and the degree of operational and technological damage. In this article a new formula has been developed that numerically determines the degree of defect resistance of materials. Experimental testing of this technique on some types of modern materials confirms its reliability. The directions of the future development of the research results are formulated.
Ways of abrasive blasting technology development
Authors: Sychuk V A , Zabolotnyi O V 
Published: February 2021

Abstract
Having analysed problems in abrasive blasting processing, we present solutions. To reduce the probability of failure of the abrasive blasting nozzle, it is necessary to reduce or eliminate the fact of its wear using the air layer between the inner working wall of this tool with the flow of abrasive particles. It is also preferable to remake the layout of the nozzle from solid to assembled unit in order to replace with a new part of the nozzle, which can still become wear-off because of some reasons. As a result of implementation of such abrasive blasting nozzle, there was a need to develop the method of its use. Regarding the quality control of the processed surface, it is usually carried out in such ways: visually during processing; after processing; due to certain processing modes, which are predicted to provide a given surface quality. Using the methods presenting above it is impossible to quantify the quality of the surface, especially during machining. Accordingly, the processed part in some cases returns to machining again. Therefore, it is suggested that active control should be applied, namely to measure, for example, the roughness of the resulting surface during processing. If the degree of roughness is not reached, a signal is sent to the worker or the automated system about the need to finish the surface, or change the processing modes, which will provide the desired result.
Application of interface guided waves for structural health monitoring of hybrid bonded joints
Authors: Jahanbin Mark 
Published: February 2021

Abstract
The application of ultrasonic interface guided waves for the inspection of adhesively bonded joints is studied. A thin adhesive layer forms a bond line between the surfaces of distinct structural elements. This work demonstrates the formation of specific ultrasonic guided waves which are propagating on the boundaries of bonded joints and can be used for health monitoring of adhesive bonds. Interface waves are extremely sensitive to changes in elastic and plastic characteristics such as density and viscosity of the adhesive layer. Using finite element simulations, the changes in propagation of wave form, attenuation of leaky interface wave and Time of Flight (TOF) were observed and recorded as a baseline. Then the pervasive effect of bonding failure on these parameters are used for damage detection in adhesive bonded joints. The cohesive damages such as dis-bond and delamination are slowing down interface wave speed depending on size and location, and the adhesive properties also change the Time of Flight of propagating wave. The results of this study show that interface waves can be used to inspect adhesively bonded joints and, possibly, to determine the strength of the bond line and predict the failure mechanisms of bonded structures.
Study of the Destruction of Carbon Composite Panel using High-Speed Jet of Liquid
Authors: Abashin M I , Galinovskiy A L , Htet Kyaw Myo , Denisova A V , Erokhin S A , Chzheniuan TSzia 
Published: February 2021

Abstract
The article discusses the task of assessing the damage of carbon fibre plastics arising from the destructive effect of radiation using the diagnostic capabilities of ultra-jet technology. A technique is proposed for determining the thickness of a carbon fibre package that can protect an imaginary interior from the negative effects of radiation waves. As informative diagnostic parameters in the method, the geometrical dimensions of the cavern created on the surface of the sample following exposure to a high-speed jet of liquid (water) are used. Based on the results of the experiments, it was found that a decrease in the depth value indicates a decrease in the penetrating effect of radiation and the destruction of the binder in the structure of the composite material.
Influence of the profile of longitudinal grooves of various depths on increasing static characteristics of radial gas bearings
Authors: Vishtak I V , Petrov O V , Savulyak V I , Sukhorukov S I 
Published: February 2021

Abstract
Radial gas bearings with one line for supplying compressed gas to the working gap with blind microgrooves of constant width and variable depth of the different profiles are considered. Such as with constant depth microgrooves; triangular or stepwise with decreasing depth of grooves along the course of compressed gas. For them, the radial lifting force, the recovery moment for angular displacements of shaft in the range of constancy of radial and angular stiffness and consumption of compressed gas for the bearing’s work are found. Calculations and studies have shown that a radial bearing with longitudinal microgrooves whose depth decreases linearly in the direction of gas flow has a large radial lifting force and a recovery moment for angular displacements of shaft compared to a bearing with microgrooves of constant depth. Bearings with stepped longitudinal microgrooves with greater depth at the entrance to working gap are operable in the range of practical use of bearings and have greater dimensionless radial and angular stiffness and are more economical compared to bearings with microgrooves of constant depth. In practical activities (when designing spindle units), it is not recommended to use gas bearings with a variable depth of microgrooves having a minimum depth at the entrance to working gap. With optimal design parameters, the flow rate of compressed gas for bearings with longitudinal microgrooves of different transverse profiles with alignment of shaft and sleeve is almost the same (the difference is about 7, 8%).
Ultralight structurally optimized carbon fibre reinforced polymer composite wing designing based on parametric modelling and topology optimization
Authors: Baranovski S V , Mikhailovskiy K V 
Published: February 2021

Abstract
The passenger aircraft wing is an extremely complex object, especially in design, in which it is necessary to take into account many different factors, physical processes and phenomena both in individual areas of science and engineering, and at their junction. The main enlarged areas and issues that are solved during the development of wings include aerodynamics, aeroelasticity, strength, stability, and manufacturability. All this causes significant time and labour costs, especially at the stage of design calculations. In this connection, the urgent task of compiling a universal integrated methodology for designing a wing of polymer composite materials, which allows to accelerate and facilitate the selection of design parameters at the stage of outline design. The methodology being developed is tested on the passenger aircraft wing and takes into account the choice of the geometric shape of the wing, taking into account optimal aerodynamics and minimizing the operating loads, determining the position of the main power elements providing the necessary structural strength, as well as calculating the main structural parameters of individual polymer composite elements.
Prediction and detection of primary microcracks in carbon fiber reinforced polymer under load
Authors: Mikhaylovskiy K V , Reznik S V 
Published: February 2021

Abstract
Carbon fiber reinforced polymers (CFRP) are widely used in the manufacturing of critical parts and structures in the aerospace industry due to the combination of low density, high strength, and stiffness. Production of parts and structures with pre-predicted properties is a difficult task provided significant anisotropy of physical properties and complex microstructure. The solution to this problem has to be based on the correct mathematical model describing the behavior of parts and structures made of CFRP under operational loads. Moreover, experimental data on physical, mechanical, and thermophysical properties and their change depending on the number of loading cycles has to be implemented. In view of the above, prediction of the occurrence and development of microcracks in the material becomes significant. The aim of this article is to develop algorithms for prediction and detection of primary microcracks in CFRP under loading using fiber Bragg grating (FBG) sensors and multiscale mathematical modeling. The results of measuring the primary residual deformations in the plates made of CFRP at the manufacturing stage by embedded FBG sensors and testing its performance under loading was presented. Multiscale mathematical modeling of a numerical experiment performed to evaluate the occurrence of areas of primary microcracks in CFRP under loads. It is demonstrated that splitting of peaks of resonant wavelengths of embedded FBG sensors indicates the occurrence of primary damage and microcracks.
Parametric identification of thermophysical characteristics of heat-protective decaying materials
Authors: Aldebenev N S , Yu Ganigin S , Demoretsky D A , Diligenskaya A N , Yu Livshits M 
Published: February 2021

Abstract
The paper presents a method of identifying the thermophysical properties of heat-protective materials of complex multi-component composition used in structures to meet the specified requirements for their resistance to external temperature influence. The research is dedicated to the study of a thermal barrier coating material containing chemically active components that enter into a chemical decomposition process, accompanied by the heat absorption. The equivalent specific heat capacity of the material reflects its thermophysical properties, taking into account the endothermic reaction. The equivalent specific heat capacity is identified by solving the inverse heat conduction problem using the results of temperature measurement in a multi-layer structure element during the thermophysical experiment. Regularization of this incorrect inverse problem is performed when it is transformed into a mini-max parametric problem of semi-infinite optimization. The results of differential thermal analysis and known qualitative laws of endothermic reactions make it possible to narrow the set of feasible solutions to the level of a compact set of piecewise continuous functions of a special structure, which provides a reduction to the parametric optimization problem. The minimax problem is solved by an alternance optimization method. The results obtained confirm the effectiveness of the proposed method for solving applied problems.
Effects of Surface Reactions during Friction on Tribological Characteristics of PTFE-Muscovite Composites
Authors: Sleptsova S A , Okhlopkova A A , Kapitonova Iu V , Lazareva N N , Vasiliev A P , Nikiforov L A , Tarasova P N , Laukkanen S 
Published: February 2021

Abstract
This work presents the results of tribological and structural investigations of polymer composites based on polytetrafluoroethylene and muscovite. It is shown that the wear resistance of the composites increased up to 675 times in comparison with the initial polymer. The increase of wear resistance is attributed to the occurrence of tribo-oxidation processes on the friction surface, which have been confirmed by various investigations. Thus, IR spectroscopy showed that carboxylate anions are formed on the friction surface of composites during friction processes. An increase in oxygen and a decrease in carbon and fluorine concentrations on the composite surface have been detected after friction using the EDS analysis. The results of XPS have confirmed the destruction of C-F bonds and the formation of new oxygen-containing compounds. These research methods indicated the occurrence of tribo-oxidative processes during friction.
Working efficiency analysis of space mirror antenna reflector made of composite materials
Authors: Azhevsky Y A 
Published: February 2021

Abstract
The study is devoted to the possibility of using composite materials, composite sandwich panels and composite mesh structures as constructions for space mirror antennas using at space satellites. The modelling of the thermal and stress-strain states of the structure, which are characteristic of radiation heat transfer in open space operating conditions, has been carried out. Based on the results obtained, a design with the best indicators of mass-dimensional stability under operating conditions was selected.
Design, development and performance evaluation of a large-scale hybrid solar dryer
Authors: Naigam A P V , Ridzuan I M B , Tan A S T , Abdullah A , Wan Ismail W A A Z , Janaun J 
Published: February 2021

Abstract
A large-scale hybrid solar dryer was developed to account the limitations encountered in traditional open sun drying. With loading capacity of 500 kg and incorporated with a hybrid heating control system, this dryer is suitable for industrial drying that requires large drying capacity and products with high moisture content. In addition, this drying system offers flexibility in switching between different combinations of air vents based on the drying purpose required. Chaotic air flow produced in the drying chamber ensure uniform temperature distribution across the drying trays in an updraft air movement. Potential application of the drying system for durian skin and chili drying were tested. Based on the performance evaluation, a maximum temperature and maximum average temperature of 66°C and 59°C, respectively, was attained in the drying chamber. The drying of chilli with the drying temperature set at 50°C and operating condition of using the ventilation fan and opening the air vent achieved the drying time of 5 days or 45 hours in total, equivalent to 9 hours of drying time per day.
Effects of variable heat source on convective motion in an anisotropic porous layer
Authors: Nagarathnamma H , Ananda K , Gangadharaiah Y H 
Published: February 2021

Abstract
The onset of convective motion in a fluid saturated anisotropic porous medium layer is examined analytically in the occurrence of the qualitative effect of the source of variable internal heat. Three different kinds of heat source functions: (i) N (z) = z (linear) (ii)N(z) = z2 (parabolic) and (iii) N (z) = z
3 (cubic) are considered. The resulting eigenvalue problem was analytically solved using regular perturbation technique. A parametric study is carried out by varying the following parameters: the heat source parameter (X), thermal anisotropy parameter(n), and mechanical anisotropy parameter(ξ). Results indicates that the effects of the increasing values of λ and ξ will enhance the convection of a anisotropic porous layer system while the increasing of n will help to stabilize the system. It is also noted that for case (iii) the system is more stable, while for case (i) the system is more unstable
Bounds for α—Adjacency Energy of a Graph
Authors: Shanmukha B. , Shwetha H. N , Manjunath N 
Published: February 2021

AbstractRecently Nikiforov et.al [9] put forward theα—adjacencey energy of a graphG. In this paper, we continue the work onα—adjacencey energy and obtain bounds for this new parameter in terms of order, size and the first Zagreb index.
Polymethacrylic acid functionalised with dihydroxy benzene as an adsorbent for the removal of Malachite Green dye
Authors: Devakumar J , Ramesh V , Amaladass P , Jaya Santhi R 
Published: February 2021

Abstract
The present work reports the investigation performed by comparing the adsorption abilities of modified/grafted polymethacrylic acid (PMAA) functionalized with dihydroxy benzene like catechol (CAT) and catechol-hydroquinone (CAT-HQ) by an oxidative decarboxylation method using potassium dichromate as an oxidant to absorb Malachite green (MG) dye from aqueous solution through batch experiments. The percentage of substitution of monomers with PMAA was found to be 94.5% and 95.7% for PMAA/CAT and PMAA/CAT-HQ respectively. The FTIR and SEM studies were determined to reveal the modification of PMAA. In order to efficiently extract malachite green from the aqueous solution, the effects of different parameters like contact time, pH, dye concentration and adsorbent dosage were systematically studied. The change on the surface morphology of the polymers after the adsorption of dye was analysed using FT-IR spectra and SEM images and found to have considerable changes after the adsorption of the chosen dye. The test of adsorption studies has shown that the Langmuir isotherm model is better than the Freundlich model. The monolayer adsorption capacity of PMAA/CAT and PMAA/CAT-HQ were found to be 97mg/g and 102 mg/g at 31°C.
Evaluating Self-sensing Property of Carbon Fibre Cement Composite by experimental study and Finite Element Modelling For Structural Health Monitoring Applications
Authors: Roopa A.K , Hunashyal Anand M. 
Published: February 2021

Abstract
Structural health monitoring (SHM) is a novel area of research and it is the process of implementing a damage detection strategy. The initial step of implementation a SHM system involves, incorporating structural self-sensing capability of material to achieve the reliability and possesses long term stability. Smart sensing technologies involves the applications of fiber optic sensors and self-diagnosing fiber reinforced composites which possess important capabilities of monitoring various physical or chemical parameters to achieve the durable service life of structures. The addition Carbon fiber to concrete composites possess the electric properties, therefore it can be used as Smart sensing composite that provide the capability of non-destructive flaw detection in structures. In this paper, carbon fiber (CF’s) is added to cement composite to attain piezoresistive properties of composite. This carbon fiber is added in the composite by forming tube which act as conductive element. Later on, electromechanical test is conducted to this sensor by embedded into structural elements that is in beam and column to evaluate self-sensing properties. Scanning electron microscope is carried to understand the morphology of sample. A Finite elemental modeling is done to validate this experimental result. A FEA modelling is carried out using ANSYS software, subjected to steady steady static loading and electric analysis were done. Form the experimental is observed that addition carbon fiber induces conductivity property and the resistance decrease for failure load. The resistivity from experimental study observed is 9.2 kilo ohms and 11.2 kilo ohms for embedded carbon fibre sensor into beam and column respectively. The percentage error in electrical analysis of experimental tests compared with analytical modelling, found to be 15 %. Based on these results it can be concluded that carbon fiber cement composites have great potential and they can be used for structural health monitoring applications.
Response spectrum analysis of a G+4 building with mass irregularity on a sloped surface
Authors: Anirudh Raajan V , Balaji G C , Vasavi V 
Published: February 2021

Abstract
The behaviour and stability of a multi-storey building in a sloped region depends on structural configuration. Irregularities in the structure are recognized as one of the chief sources of its failure. Structures commonly have a grouping of irregularities such as vertical irregularity, mass regularity, stiffness irregularity etc. Also, for the analysis of such a structure, it is necessary to carry out dynamic analysis to determine the maximum peak response of the building with respect to the natural time period. Since it would be difficult to get the time history record for all the places, it is feasible to go with Response Spectrum Analysis. In this paper, a G+4 RCC building having each storey of height 3.5m placed in the sloping ground with horizontal angle of inclination 20° for the purpose of dwelling of people during disaster with one of the storey to be used for storage of food and water which induces Mass irregularity. The structure is modelled in ETABS software. Here the mass irregularity is induced at every storey by inducing on one storey at a time for 3 different zones (III, IV, V) and the same has been analysed by inducing gravity loads and seismic load cases using Response Spectrum Analysis. The response of the structure with respect to variation in the Storey Drift and Storey displacement has been recorded and will be discussed elaborately.
Effect of elevated temperature on the mechanical strength of glass mortar
Authors: Patil S S , Patil Y D 
Published: February 2021

Abstract
This experimental study aimed to investigate the elevated temperature behavior of glass powder (GP) as a partial replacement of Portland cement. The residual compressive strength is an essential consideration for the sustainability of newly introduced supplementary cementitious material at elevated temperatures. For this study, the powder of waste glass was used to replace portland cement in the proportion of 0%, 10%,20%, and 30%. For fundamental understanding, the compressive strength test was carried out on samples after exposure to high temperature with two different cooling regimes. The experimental result reveals that the mortar mix with cement replaced by 20% GP for both cooling conditions retained more relative residual strength and showed sound behavior compare to the reference sample. The mortar sample with 20% glass powder replacement shows better performance with lower strength loss for both cooling regimes. For air cooling samples, the average strength loss was 27.0% compared to 31.2% of the reference sample. In water cooling samples, the average strength loss was 25.4% compared to the 30.7% reference sample. The two distinct temperature ranges were observed regarding the effect of glass powder replacement on mortar strength under elevated temperature. For temperature above 400 °C average strength loss was 38.62% in the mortar with glass powder and 35.60%in reference sample for water cooling condition. Similarly, for air-cooling samples, the average strength loss was 51.8% compared to 48.90% of the reference sample. Therefore, the lesser strength loss of mortars containing glass powder may be related with their low calcium hydroxide content.