bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of laser energy and wavelength on average size of gold nanoparticles synthesized by pulsed laser ablation in deionized water
Authors: Jamaludin N , Chaudhary K T , Haider Z , Duralim M , Ismail F D , Roslan M S , Amira N H , Ali J 
Published: June 2020

Abstract
In this paper, the effect of Nd:YAG laser wavelength and energy on the synthesis of gold nanoparticles is reported. Gold nanoparticles colloidal solutions were prepared by pulsed laser ablation of gold target in deionized water. The Nd:YAG laser with repetition rate of 1 Hz was assigned to supply energy at fundamental and second harmonic wavelengths i.e., 1064 nm and 532 nm, respectively. Synthesized nanoparticles were characterized using particle size analyzer (PSA). Four different laser energies were used to ablate the samples and synthesize gold nanoparticles. The average size of gold nanoparticles was found to decrease with increasing laser energy. The gold nanoparticles of smaller size were obtained when the target was ablated with 532nm wavelength of Nd:YAG laser. Higher laser energies and efficient absorption of 532 nm wavelength resulted in size reduction by fragmentation of colloidal nanoparticles.
The tissue temperature during injection of drug solution into it as an integral indicator of rheology
Authors: Urakov A , Gurevich K , Alies M , Reshetnikov A , Kasatkin A , Urakova N 
Published: June 2020

AbstractThe dynamics of local temperature in the area of injection of drug solutions with regard to their physical and chemical properties is studied. It is shown that infrared thermography allows to visualize the processes of intra tissue rheology of drugs both when the temperature of injected drugs differs from the local temperature of tissues in the injection area and when their temperatures are equal. Methods of infrared diagnostics of tissue homogeneity, as well as methods for identifying, specifying the localization, shape and size of tumors, foreign bodies and local inflammations have been developed. It is shown that artificial temperature contrast of veins filled with blood and/or drug solutions in relation to the tissues surrounding them allows to visualize these structures using a thermal imager in real time. It is established that the dynamics of the local temperature of tissues at the injection sites of drug solutions depends not only on the temperature of the injected drugs, but also on the presence and severity of their local irritant effect. It is shown that the local irritating effect of drugs is manifested in the places of their injections by local hyperthermia, hyperemia, swelling and soreness. A direct dependence of the severity of the local irritant effect of drugs on the value of the total concentration of ingredients and the degree of hyperosmotic activity of solutions was established. Therefore, dilution of drugs with water is a way to reduce their local irritant effect.
Simulation of the residual stress in a multi-pass oil and gas pipe weld joint
Authors: Hasan Alhafadhi Mahmood , Krallics Gyorgy 
Published: June 2020

Abstract
In this paper, a welding simulation procedure is developed using the FE software MSC Marc to predict the residual stresses.Numerical simulation was used to predict the thermal, mechanical and residual stresses behaviour in dissimilar material welded pipes which were found to be in good concurrence with experiments. Both two-dimensional FE model (2D) and three-dimensional FE model (3D) models are used to simulate the residual stressesin different directions in several regions of the weld zone under the same welding conditions. The 2D modelwas used toreduce the time and cost of numerical simulation.The aimof the present work is to understand the evolution of residual stresses (axial, radial and hoop stresses) in weldments. The results of thesimulationreveal that the hoop and the axial residual stresses around the weld region arenoticeablyvarying from those in the steady range.
Clay-cement suspensions based on Belchatow and Patoka polymineral clays – rheological characteristics
Authors: Litwinek-Rozbicka E , Izak P , ŁWójcik  , Mastalska-Popławska J 
Published: June 2020

Abstract
The results of studies concerning freshly prepared clay-cement sealing suspensions based on Bełchatów and Patoka polymineral clays, Portland cement and the addition of sodium water glass as the initiator of the hydration process were reported. Flow curves were determined in a coaxial cylinder system. On their basis, power of destruction and rebuilding of the thixotropic structure was calculated. Changes of the elasticity modulus G’ and viscosity modulus G’' were determined by oscillatory measurements in the plate - plate system at variable frequencies. The influence of the type of clay mineral and its content on the tendency to form a thixotropic structure was defined.
Rheology of uncured magnetorheological elastomers
Authors: Moucka R , Sedlacik M , Ronzova A 
Published: June 2020

Abstract
The aim of this paper is to study rheological properties of uncured magnetorheological elastomers comprising iron particles dispersed in silicon elastomer in relation to particle rearrangement by external magnetic field into oriented structures as this process is strongly affected by viscosity. Studied systems vary in used filler volume concentration (0 to 30 vol. %). From measured flow curves flow consistency index is extracted first by fitting experimental data to Herschel-Bulkley model followed by applying two concentration dependency models (Maron-Pierce and Krieger-Dougherty) to normed consistency. Results and model predictions are discussed.
Rheology Behaviour and Mechanical properties of Poly(vinyl alcohol) Membranes Modified with Nanodiamonds
Authors: Remiš Tomáš , Kadlec Jaroslav , Kovářík Tomáš 
Published: June 2020

Abstract
Poly (vinyl alcohol) (PVA) membranes have found wide application in biomedicine and pharmacy for their unique properties such as biocompatibility, elasticity and the ability to absorb large amounts of water. Also carbon nanomaterials have shown great potential in a number of applications in regenerative medicine. Nanodiamonds (ND) are a unique class of carbon nanoparticles that have become known thanks to their biocompatibility, highly functional surface and unique physical, chemical and optical properties. Nanocomposite membranes based on PVA and ND were prepared by a solution casting method to achieve an even distribution of ND in the PVA matrix. The resulting nanocomposites have excellent properties derived from ND and PVA. The mechanical properties of the membranes improved significantly with an increase in ND, suggesting a strong chemical interaction between ND and PVA. The SEM showed a uniform distribution of ND in the PVA membrane. From the results of the work we assume that ND are a suitable nano-filler for PVA membranes. This work examines the properties of ND-reinforced PVA membranes and their potential use in biomedical applications.
Using Crumb Rubber to Improve the Bituminous Mixes: Experimental Investigation of Rutting Behavior of Flexible Asphalt Mix for Road Construction
Authors: Qassim Al-Salih Wissam 
Published: June 2020

Abstract
Tires that are simply thrown away are a serious environmental problem and safe disposal is a difficult problem. Using the crumb rubber (CR) obtained from shredding of those scrap tires in roads is an alternative solution to their safe disposal. On the other side, excessive rutting in the bituminous layer is a structural defect associated with functional implications. Wheel loads and high pavement temperatures are environmental factors which the main cause of premature rutting. Modified binders and rut resistant mixes especially gradations can reduce premature rutting. The object of the paper to solve two main problems: firstly, the solution to the problem of the tires waste to safe disposal and; secondly, to study the rutting behaviour in bituminous mixes modified by tires waste in CR form. In this paper, two types of bituminous mixes, stone matrix asphalt and bituminous concrete those are used to carry wheel tracking test. The results are shown by using Marshall Test that 6% of CR content by weight if normal binder 60/70 content and optimum binder content for the binder in bituminous mixes is 5.1% & 5.5% by weight of mix is have improved the bituminous mixes. In addition, results indicated that the mixes prepared with a modified binder by CR are good in forming rut resisting mixes. The benefit of this study is the tires waste disposal in an environment-friendly way and better road to withstand rutting.
Numerically simulated prediction of residual stresses in welding considering phase transformation effects
Authors: Hasan Alhafadhi Mahmood , Krallics Gyorgy 
Published: June 2020

Abstract
This work deals with investigating the effects of solid-state phase transformation on residual stresses during the welding of low carbon and high carbon steels. In this study, depending on MSC Marc code, the simulation considers the local microstructure properties changes due to the thermal welding cycles. A sequentially coupled thermal and mechanical 2-D finite element model (FEM) was used. In FEM, phase transformation temperature diagrams are used to anticipate the amount of martensite in the fusion zone (FZ), and heat affects zone (HAZ). The simulation results demonstrated that the residual stress in low carbon steel is not affected by the volume change caused bythe austenite-martensite transformation. In contrarily,the residual stressesin the high carbon steel are considerably influenced by the martensitic transformation.
About mechanical behaviour of metal matrix composites under shock wave loading
Authors: Karakulov V V , Yu Smolin I , Kulkov S N 
Published: June 2020

Abstract
In this work the results of studying of the mechanical behaviour of metal-ceramic composites with an aluminium matrix on meso-scale level are submitted. Computer simulation of mechanical reaction of representative volume of composite material, considered as ensemble of the interacting structural elements (ceramic particles and metal matrix), is used for studying mechanisms of deformation on meso-scale level of metal-ceramic composites under the loading by shock waves. The mechanical behaviour of aluminium matrix is described by the model of the damaged elastic-plastic medium. The model of the damaged brittle solid is used for ceramics. The absence of macroscopic and mesoscopic voids and cracks in the material before loading is assumed. Ideal adhesion of ceramic material to metal is supposed at the initial condition. The problem is solved in 2D statement with application of finite-difference method. Results of numerical simulation of the mechanical behaviour of metal-ceramic composites under shock wave loading have shown the formation of non-stationary and essentially non-uniform fields of stresses and strains at the meso-scale level. The generation of a dissipative structure on the meso-scale level of the composites under shock wave loading was revealed in the simulations.
The features of fracture processes of the ceramic composite
Authors: Mikushina V A 
Published: June 2020

Abstract
The phenomenon of material fracture spans many different length scales. The paper is devoted to the numerical investigation of the features of fracture processes in alumina-zirconia composite ceramics at the mesoscale subjected to uniaxial compression. A structural model of the composite mesovolume based on the experimental SEM image is adopted. The mechanical behavior of the composite is described by a constitutive model of the damageable elastic-brittle medium. Two local fracture criteria are used that are based on the limit values of damage and tensile pressure. The energy dissipation process in the ceramic composite mesovolume during damage accumulation is analyzed. It is shown that the damage accumulation results in nonlinear dissipation of potential energy and the following kinetic energy increase. The last is accompanied by the appearance and growth of cracks in matrix and inclusions at the final stages of deformation.
Formation and characterisation of cobalt depleted outermost layer of WC–Co composite materials
Authors: Rugóczky Peter , Muránszky Gábor , Lassú Gábor , Lakatos János 
Published: June 2020

Abstract
The cobalt depleted layer of WC–Co composite materials was investigated after selective cobalt etching in diluted Caro’s acid. The time dependence of Co etching and the thickness of the etched layer was determined by using Glow Discharge Optical Emission Spectrometer (GD-OES) depth profiling as well as by calculation method based on determination of the dissolved Co by Atomic Absorption Spectrophotometric (AAS) measurement. The integrity of the modified outermost layer of the WC–Co composite materials were qualified using Rockwell C indentation test. This test methods were found usable for optimisation of the pre-treatment applied before the diamond thin film deposition.
Microstructural evaluation and thermal properties of sol-gel derived silica-titania based porous glasses
Authors: Deshmukh Kalim , Kovářík Tomáš , Křenek Tomáš , Stich Theresia , Docheva Denitsa 
Published: June 2020

Abstract
In recent years, the sol-gel synthesis of porous glasses has drawn widespread attention owing to the convenience and versatility of the sol-gel method. The sol-gel synthesis process mainly involves hydrolysis and condensation of precursors followed by drying and stabilization. In the present study, silica-titania (Si-Ti) based porous glasses with different compositions were synthesized using the sol-gel method. In general, the final properties of solgel derived glasses significantly depend on the characteristics such as pore structure, pore size, morphology and the compositions of the precursor materials. The influence of these processing parameters on the microstructural and thermal properties of Si-Ti based glasses has been investigated. The microstructures of the synthesized Si-Ti based porous glasses were investigated using scanning electron microscopy (SEM) and the thermal properties were evaluated using thermogravimetric analysis (TGA) and thermomechanical analysis (TMA). The main objective of the present study is to utilize these Si-Ti porous glasses as a potential biomaterial for bone tissue regeneration. Therefore, to understand this facet of Si-Ti porous glasses, it is essential to investigate their physical and microstructural properties.
The effect of expanded perlite on fired clay bricks
Authors: Hamza Alexandra , Kocserha István 
Published: June 2020

Abstract
Nowadays stricter energy regulations are compelling us to further improve the thermal insulation performance of current building materials. In this study we investigated the possibility of improving the thermal insulating performance of fired clay bricks. In our work we used two types of additives: sawdust, which is a general additive, and expanded perlite, which is typically a synthetic additive based on SiO2 and Al2O3. Sawdust and expanded perlite in amounts varying between 3.35-6.5 wt% were mixed into a clay masses to prepare test samples by pan mill. The moisture content of the clay masses was 25 wt%. Samples were prepared using a laboratory vacuum extruder, after which they were dried, and then sintered at 880 °C. The fired specimens were measured for firing shrinkage, water absorption, bulk density, and compressive strength. Furthermore, we determined the thermal conductivity of the specimens. The purpose of our research was to examine the usability of expanded perlite as an additive in brick manufacturing, and also to compare the results with sawdust, one of the most popular additives. In addition, measurements were made using the two additives together.
The Use of Si-B Alloys in Thermal Energy Storage System
Authors: Meng Jiao Jian , Grorud Bettina , Safarian Jafar , Tangstad Merete 
Published: June 2020

Abstract
Si-B alloys are considered as phase change materials (PCMs) in the thermal energy storage (TES) systems due to their high latent heats and moderate temperatures. In order to successful apply them, proper Si-B alloy composition and a suitable ceramic refractory material that can survive long time corrosion at high temperatures should be determined. Here, we investigate serials of Si-B alloys with the B range of 2-11 mass % in graphite crucibles in the temperature range 1450-1750 °C. This work shows that the interaction between Si-B alloys and graphite goes into two stages. Single SiC is formed at the interface at the B content of 2 mass %. SiC and B4C are produced at the interface at the B contents of higher than 5 mass %. Additionally, the results of structural characterization are supported by thermodynamic calculation. These results provide reliable data in the use of Si-B alloys as PCMs in the TES systems.
Effect of activation and exfoliation on the formation of carbon nanosheets derived from natural materials
Authors: Nuilek K , Simon A , Kurovics E , Ibrahim J F M , Varanasi D , Baumli P 
Published: June 2020

Abstract
Carbon is abundantly found in nature with a wide range of applications. It can be synthesized through physical and chemical processes. Chemical activation is considered as a very efficient method to obtain carbon with high surface area and narrow micropore distribution. Among all the chemical activating agents, alkaline hydroxides such as potassium hydroxide (KOH) or sodium hydroxide (NaOH) are reported to be of high interest in the production of carbon with higher performance. In our research, Nettle stem and peanut shell (natural materials) were used as raw materials for the preparation of carbon. Natural structures of nettle and peanut shell consists of cellulose, which is an important precursor in the preparation of highly ordered carbon nanosheets. Aqueous solutions of KOH and NaOH were used for activation and sulphuric acid (H2SO4) was used for exfoliation. The process employed here has yielded a high percentage of carbon nanostructured particles.
The role of purity level in foundry silica sand on its thermal properties
Authors: Svidró Judit , Tamás Svidró József , Diószegi Attila 
Published: June 2020

Abstract
Silica sand is the most commonly used mineral for molding and core making applications in foundry technology due to its availability, thermal and chemical attributes. However, there are many additional requirements foundry sands need to meet regarding their sizing, chemical purity, physical durability and thermal properties. This research studies the thermophysical properties of a foundry silica sand comprehensively. After separating one sand batch into numerous grain size ranges, the chemical composition and thermophysical properties of the fractions were investigated, respectively. By means of this approach, the chemical properties and thermal behavior can be directly linked. The silicon dioxide content shows a strong correlation with the thermal expansion properties of the various fractions. The results give a better understanding of the high temperature behavior of foundry silica sands and clarify the role of factors affecting their thermophysical properties.
The content of the adsorption centers of high-silica porous glasses
Authors: Tsyganova T A , Mjakin S V , Kostyreva T G 
Published: June 2020

Abstract
Changes in the specific surface, pore size and content of Lewis (siloxane) and Brønsted (silanol) surface groups for high-silica nanoporous glass with a sponge-corpuscular structure depending on their thickness and storage time are studied and interpreted in terms of porous structure features, hydration and aging effects.
Laser ablation of silicon monoxide and titanium monoxide in liquid: formation of mixed colloidal dispersion with photocatalytic activity
Authors: Vála Lukáš , Vavruňková Veronika , Jandová Věra , Křenek Tomáš 
Published: June 2020

Abstract
Silica–titania mixed oxides and composites have been extensively studied, whereas to the titanium monoxide (TiO) –silicon monoxide (SiO) counterparts has been devoted very little attention. Laser ablation of SiO and TiO in liquids is in according with literature completely unexplored. Here we report on Nd:YAG pulse laser ablation of SiO and TiO in ethanol which allows generation of SiO- and TiO-based nanoparticles and their agglomerates.
Mixed SiO-TiO colloid has been prepared by simple mixing of ablatively prepared individual colloids in 1:1 volume ratio. Measurement of size distribution by Dynamic Light Scattering (DLS) determines sizes of 24.85 nm and 262.3 nm for SiO colloid, 494.8 nm for TiO colloid and 35.2 nm and 397.5 nm for mixed colloid. Zeta potential values suggest incipient instability for all measured systems. Morphology of the particles captured on Ta substrate by evaporation of ethanol was studied using Scanning Electron Microscopy (SEM). Round-shaped, oval, and sheet-like particles and their agglomerates have been observed. Raman spectroscopy of the mixed SiO-TiO colloid revealed multiphase structure consisting of anatase and/or rutile, crystalline and amorphous silicon and silica and crystalline and amorphous titanium silicide TiSi2. Formation of TiSi2 demonstrates unexpected low temperature disproportionation of SiO and TiO-based species and mutual reducing interactions. Catalytic activity of individual SiO and TiO colloids and of their mixture has been tested in terms of methylene blue (MB) degradation under the daylight. TiO-SiO mixture exhibits higher solar-light catalytic activity compared to individual colloids which could by explain by the presence of highly photocatalytic TiSi2. These results represent potential of SiO and TiO reducing interactions which are favorable for generation of photocatalytic materials for water remediation.
Estimating domestic self-supply groundwater use in urban continental Africa
Authors: Chávez García Silva Rafael , Grönwall Jenny , van der Kwast Johannes , Danert Kerstin , Foppen Jan Willem 
Published: June 2020

Abstract
Self-supply of groundwater for domestic use in urban sub-Saharan Africa (SSA) is common, but the extent to which it is practiced is unknown. We developed an open data based GIS method for continental Africa (without islands) using groundwater storage, depth to groundwater, aquifer productivity, and population density data. Furthermore, we developed proxies for public supply network coverage and socio-economic status, incorporating restriction measures for groundwater use. Our results indicate that in 2015 about 369 million urban inhabitants (∼79% of the total urban population) of continental Africa could potentially supply themselves with groundwater. However, the likely number of urban inhabitants using groundwater obtained via self-supply was less: about 150 million (∼32% of the total urban population). With the novel GIS based methodology presented here, the urban population using self-supply groundwater for domestic use can be determined, which is essential to inform policy and practice, and to influence public investment.