Properties Of Samples Research Articles

THE IMPACT OF STARTER CULTURES ON QUARK TYPE CHEESE PRODUCTION

This study was conducted to investigate the effect of starter cultures on the physicochemical and microbiological properties, texture, yield, and consumer preferences of quark type cheese. For this purpose, three different quark cheeses were manufactured by using commercial starter cultures. The microbiological, physicochemical, textural, and sensory properties of the cheese samples were determined at 1st, 14th, and 28th days of the storage period. The results showed that the kind of starter culture used in production influences the composition and yield of the obtained quark cheeses. It has been determined that the use of kefir culture in quark cheese production influences the moisture and water holding capacity, and as a result, improves its spreadability. Also, the sensory analysis exhibited that cheese produced with kefir culture had higher texture and taste-flavor acceptability. The study indicates that kefir culture may be successfully used in quark cheese production.

Investigating radiation shielding parameters for X-ray attenuation at various energies in locally produced ceramic materials used in Saudi Arabia

To assess shielding effectiveness against X-rays, a number of locally collected ceramic samples were obtained from the Kingdom of Saudi Arabia. Based on elemental analysis, all of the ceramic samples have a density in the range of 1.68–1.85 g/cm3, with the highest proportions of O, Si, C, and Al atoms and the lowest amounts of Na, Mg, K, Ca, Ti, and Fe. The 320 kV X-ray source (Gulmay Limited, Byfleet, UK) was used to assess the attenuation properties of the ceramic samples. An Exradin A4 ionization chamber (Standard Imaging, Middleton, USA) connected to a UNIDOS electrometer (PTW, Freiburg, Germany) in the control room was used to detect the attenuation properties. Several X-ray attenuation coefficients are evaluated at different X-ray energies in the range of 40–150 kV in this study. These include the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP). The ability of any ceramic sample under investigation to shield radiation at low X-ray energy is indicated by the theoretical and experimental values of LAC. The potential applications of these easily accessible, reasonably priced ceramic materials for radiation protection in X-ray labs and low-energy X-ray shielding in a variety of fields have been shown by this investigation.

Non-destructive detection of fructose solutions via Terahertz spectroscopy enhanced by Frequency Selective Surface (FSS)

Terahertz (THz) spectroscopy, combined with Frequency Selective Surfaces (FSS), is emerging as a powerful non-destructive technique for detecting and analysing the properties of biological samples. In this study, we explored the use of THz spectroscopy for detecting fructose solutions with concentrations ranging from 0.2 % to 10 %. Using femtosecond laser light sources, the THz transmission and absorption characteristics of fructose were investigated. The integration of FSS significantly enhanced the sensitivity of THz detection, yielding a 16 % improvement at 1.29 THz and 28 % at 1.67 THz. UV–Vis and Fourier Transform Infrared (FTIR) spectroscopy were employed to compare results with traditional methods, highlighting the superior sensitivity of THz spectroscopy, especially at low concentrations. The findings suggest that THz spectroscopy, enhanced by FSS, has strong potential for advancing non-invasive testing in biological and environmental applications.

Modulating Near-Infrared Persistent Luminescence via Diverse Preparation Approaches.

Near-infrared (NIR) persistent luminescence (PersL) materials have attracted extensive attention due to their great promise in medical diagnostics, bio-imaging, night vision surveillance, multi-level anticounterfeiting, and information encryption. To achieve NIR PersL (micro/nano-) materials with the desired properties, a variety of synthesis methods have been employed, including solid-phase reaction and liquid-phase synthesis. Different synthesis methods have different but important effects on the micro/nano-structure, luminescence, and PersL properties of the materials. Moreover, the influence of various synthesis methods on the properties of NIR PersL materials determines the selection of preparation approaches for other new material systems. Taking the representative NIR PersL ZnGa2O4:Cr3+ material as an example, four synthesis procedures are applied, namely, high-temperature solid-state reaction (SSR), high-temperature molten salt method (MSM), hydrothermal method (HM), and microwave-assisted solid-state (MASS) method. The structural and luminescent properties of samples made by SSR, MSM, HM, and MASS are compared. Notably, it is revealed that the MASS method can create additional trapping energy levels, which is of great significance for emerging applications. This work demonstrates the different effects of synthesis methods on PersL performance and provides a good guideline for the rapid and reasonable selection of preparation methods for diverse applications.

Influence of Multiple Repair Welding on Microstructure and Properties of 06Cr19Ni10 Stainless Steel

AbstractRepair welding technology is widely used in the manufacturing and maintenance of rail transit equipment to repair welding defects. However, repair welding induces modifications in joint performance, and it is necessary to study the microstructure evolution behavior to reveal the reasons. In this study, the effects of multiple repair welding on the microstructure, mechanical, and fatigue properties of 06Cr19Ni10 stainless steel samples were studied. The surface texture and fracture morphology analyses of the samples were conducted by optical microscopy (OM), scanning electron microscopy (SEM), and its equipped backscattered electron diffraction (EBSD) technique. The mechanical and fatigue properties of the samples with different repair welding times were further obtained by hardness, tensile, and fatigue tests. The results show an increase in the grain size and the substructure content in the heat-affected zone (HAZ), and the austenite orientation is changed, attributable to multiple repair welding. Multiple heat inputs result in a significant increase in hardness from 165 HV to 185 HV, a noticeable decrease in tensile strength and elongation, and an upward trend in yield strength. Under the constant stress level, the heat input of multiple repair welding causes a decrease in the fatigue life and significantly reduces toughness in the instantaneous fracture zone of the secondary repair sample.

Nanocrystalization effects on the structural, electrical and thermoelectric properties of 10KNbO3-10Fe2O3-50B2O3-30V2O5 glass for non-volatile electronic-memory devices

AbstractThe composition: 10KNbO3-10Fe2O3-50B2O3-30V2O5 (in mol%) is produced using the conventional melt quenching method and their corresponding glass–ceramic nanocomposites were studied. The structural properties of the as-quenched sample and its heat-treated samples were investigated using X-ray diffraction and differential thermal analysis. Density (ρ) was found to decrease with increasing average nanocrystallite size as the molar volume increases. Studies on thermoelectric power have been carried out. The glass–ceramic nanocomposite after 2 h of heating exhibits significant improvement of electrical conductivity. The activation energy (W), polaron radius (rp) and other parameters have been estimated in the non-adiabatic region. The current–voltage (I–V) curve of each sample was measured. A temporal analysis of current & voltage in nonlinear I–V curves show pinched hysteresis loop, which is the memristor’s fingerprint. The glass–ceramic nanocomposite after 2 h of heating exhibits a large switching window. The results of the study enable us to predict that they will be helpful for future applications of non-volatile electronic-memory devices.

Gamma radiation induced tailoring the structural, optical, surface and mechanical properties of UHMWPE

The present investigation examined how the resultant gamma radiation affected the ultra-high molecular weight polyethylene's (UHMWPE) mechanical, optical, surface, and structural characteristics. Different gamma doses of 75, 150, 250, and 350 kGy were applied to the UHMWPE samples. The study of physical and chemical qualities has involved a variety of spectroscopy techniques, including Fourier Transform Infrared spectroscopy, X-ray diffraction, mechanical property changes, and biocompatibility properties. New bands are formed, as indicated by FT-IR analysis, and this process is linked to the oxidation of irradiation polymer chains and the production of carbon dioxide. The crystallinity of irradiated samples increases as the gamma radiation increases, according to XRD patterns. The analyzed optical results exhibit improvements in the optical characteristics of the irradiated samples. The absorbance spectra of the irradiated samples showed a shift toward the high of wavelength values in the absorption edge as compared to the pristine sample. On the other hand, the optical absorption edge has an increasing tendency as the dose of gamma-ray radiation is increased. As the gamma-ray dose increases, the absorption edge moves toward the longer wavelength. The measurements of the contact angle indicate that the surface free energy rises with increasing gamma irradiation. It was detailed how the mechanical properties of the irradiated UHMWPE samples were measured. The mechanical measurements indicate that the mechanical properties are dose-dependent to some extent. Furthermore, as gamma doses rise, so does the hardness of irradiated UHMWPE.

The Concept of Using 3D Printing Technology in Ceramic Foundry Filter Manufacturing

AbstractThe article presents the concept of using 3D printing technology in ceramic foundry filter manufacturing. They are a crucial component for obtaining an acceptable quality of nickel superalloys by carrying out the process using the precision casting method. Commonly used filters of this type have a number of disadvantages. They are characterized by irregularity of the filtering structure, high brittleness, lack of resistance to mechanical shocks, and impacts of a stream of liquid metal. All these factors create a risk of introducing the material from the damaged filter into the casting mold, which translates into contamination of the casting alloy, and thus the occurrence of casting defects such as nonmetallic inclusions. The hope for a change in this state of affairs is the use of additive manufacturing technology in their production, which by assumption will allow to obtain a product with a repeatable shape, high mechanical resistance, and a specially designed structure regulating the flow of liquid metal into the mold during casting. The suitability of robocasting and binder jetting technology for producing filtration structures was initially assessed. The results have presented the selection of ceramic powder, as well as the development of the composition of the ceramic paste. The parameters of paste preparation and 3D printing individual processes were described. Moreover, the representative microstructures and basic mechanical properties of samples obtained by both of the compared technologies were presented. Furthermore, the final effect of prototype casting filters with a repeatable shape, manufactured with the use of both technologies, was presented, which were transferred for further technological research in a foundry producing critical aircraft engine parts. The possibilities of using each technology in various applications were also discussed.

Effect of mineralized solution on protective properties of clays in radioactive waste isolation

In this paper there were studied the mineral composition and sorption properties as well as filtration properties of natural clay samples from “Gorodnoe” deposit of Brest region and “Markovskoe” deposit of Gomel region. It was determined that clay mineral montmorillonite of the samples contains illite phase in the structure, which is 4,8 wt.% in “Gorodnoe” sample and 3,6 wt.% in “Markovskoe” sample. The illite phase was shown to contain highly selective sorption sites for 137Cs. 85Sr sorption mostly takes place on montmorillonite. It was determined that model mineralized solution (the solution imitating chemical composition of water solution if water penetrates a radioactive waste disposal and consequently passes through concrete, Na-bentonite and again concrete layers) doesn’t affect 137Cs sorption, but significantly affects 85Sr sorption. Distribution coefficients (Kd ) of 137Cs sorption on studied clay samples are higher than 103 dm3 /kg, indicating high sorption properties of the clays towards 137Cs. Kd 85Sr for sorption on the clay samples in the model mineralized solution is 30 times lower than Kd 137Cs mostly because of competition between strontium and calcium ions. It was determined that filtration coefficient values of clays from “Gorodnoe” and “Markovskoe” deposits are 2,4 and 1,3 times higher after being treated with the model mineralized solution than the filtration coefficient values for raw clay samples. Hence, the clay from “Markovskoe” deposit is more resistant to the influence of the model mineralized solution than the clay from “Gorodnoe” deposit. The overall results of the research state that the clay from “Markovskoe” deposit can be used in the underlying layer of low- and medium-level radioactive waste disposal facility at NPP.

Synthesis and characterization of some new Schiff base azo disperse dyes based on chromene moiety for simultaneous dyeing and antimicrobial finishing

New azo Schiff base disperse dyes based on a chromene moiety were synthesized by reacting (2-amino-7-hydroxy-4-(4-methoxyphenyl)-4 H-chromene-3 carbonitrile) and(2-amino-4-(3,4-dimethoxyphenyl)-7-hydroxy-4 H-chromene-3-carbonitrile), with vanillin and ninhydrin, producing new chromene Schiff base derivatives, which in turn were coupled with 2-chloro-4-nitroaniline diazonium salt to give new 4 azo disperse dyes (1–4). The structures of the prepared dyes were confirmed using elemental analysis, 1HNMR spectroscopy, mass spectrometry, and IR. The synthesized dyes were applied to polyester and nylon fabrics using different dyeing techniques: high temperature- high pressure, and ultrasonic dyeing methods. The highest K/S values for all investigated dyes were achieved usinga high temperature-high pressure dyeing technique. Also, the color reflectance of all synthesized dyes with different dyeing shades (1%, 2%, and 3%) was obtained. The fastness properties of the dyed samples using the investigated dyes showed good color fastness toward light, washing, rubbing, and perspiration fastness. The presence of a chromene moiety and Schiff base in the investigated dyes promotes a higher antimicrobial activity on nylon and polyester fabrics against all tested bacteria (E. coli gram-negative and Staphylococcus aureus gram-positive) and two fungi, Aspergillus Niger and Candida albicans.

The Effects of the Incorporation of Luminescent Vanadate Nanoparticles in Lithium Borate Glass Matrices by Various Methods

The glass-ceramic materials studied in this work are designed using combinations of lithium vanadate borate glass matrices and lanthanum/rare earth (RE) vanadate nanoparticles. Three different techniques of sintering of the glass matrix and vanadate nanoparticles are investigated. The morphological characteristics and spectral properties of the glass-ceramic samples obtained by different techniques are investigated and analyzed in comparison with the properties of the original glass matrices and nanoparticles. The luminescence spectra of all glass-ceramic samples consist of a wideband glass matrix emission and the characteristic line emission of the RE ions that are incorporated into the glass matrices as nanoparticles. The RE luminescence of these glass-ceramics is promising for various optoelectronic applications.

Physicochemical and biological properties of honey samples from Melipona beecheii Bennett collected in Hopelchén, Campeche

Physicochemical and biological properties of honey samples from Melipona beecheii Bennett collected in Hopelchén, Campeche

Identification of the Payne effect in a viscoelastic material coupling Bayesian identification and digital twin

The Payne or Fletcher-Gent effect is a particular behavior occurring in viscoelastic materials containing fillers. It induces a nonlinear dependency of the viscoelastic storage modulus on the amplitude of the applied strain. This amplitude dependency must be taken into account in engineering applications as it does change the elastodynamic behavior of the overall structure integrating the material. A methodology is developed in the proposed work to identify this nonlinear effect. The approach first starts with the identification by Bayesian inference of the frequency and damping properties of a viscoelastic sample. The input data are obtained from a modified Oberst test, conducted for different displacement load amplitudes. A digital twin of the experimental set-up is then used to evaluate the stiffness behavior, and in particular the Young's modulus of the material, at the measured frequencies, and to deduce the strain level within the sample. This work shows that the Payne effect, which leads to the decrease with the amplitude of the Young's modulus, can thus be estimated in terms of mean and standard deviation by combining experiments and numerical simulations.

Implications for galaxy property estimation revealed by CO luminosity-FWHM relations in local star-forming galaxies

ABSTRACT This study explores a relationship between the $\rm {CO}$ luminosity-full width at half-maximum linewidth linear relation (i.e. the $\rm {CO}$ LFR) and mean galaxy property of the local star-forming galaxy sample in the xCOLDGASS data base, via a mathematical statement. The whole data base galaxies were separated into two subsamples based on their stellar masses and redshifts, being a help to examine the dependence issue of the $\rm {CO}$ LFR. Selecting the galaxy data with a stringent requirement was also implemented in order to assure the validly of the $\rm {CO}$ LFR. An algorithm of the linear regression was conducted with the data of the subsample. An assessment about the linear correlation manifested a valid $\rm {CO}$ LFR occurs in the selected galaxy of the subsample, and the intercept of the $\rm {CO}$ LFR may be related with the mean galaxy properties such as the molecular gas fraction and galaxy size. For the finding on the intercept of the $\rm {CO}$ LFR, we aligned that intercept with those galaxy properties via the involvement of a $\psi$ parameter. On evaluating the $\psi$ value with our local star-forming galaxy sample, we numerically determined a relationship between the statistical result and the galaxy property in a different stellar mass range. It also shows a possible method on estimating galaxy property.

Limitations of effective medium models for tissue phantoms in the THz frequency range

The absorption of terahertz (THz) radiation by water molecules facilitates its application to several biomedical applications such as cancer detection. Therefore, it is critical for the THz technologies to be characterised with water content in a sample. In this paper, we analyse gelatine phantoms in the THz frequency range, with continuously varying hydration levels as they dry over time. Water molecules in close proximity to the protein molecule, termed ‘bound water’, feature properties different from the ‘free water’ molecules at larger distances. We find that a common model for predicting electromagnetic properties of phantoms and tissue samples, which assumes that only the free water varies with hydration while the bound water remains constant, does not agree well with measured results. To gain insight into this behaviour, we simultaneously measured the phantom in Raman spectroscopy, which shows a continuously varying concentration of bound water with hydration level. It follows from this investigation, that the permittivity contributions of neither the biomolecules nor water are expected to be linear with water density. This means that the often used, simple effective medium model will not be accurate for many biological tissues or phantoms.

Development of a flow diagram for the production of asphalt concrete mixture using polyethylene waste, contaminated with oil products

Large quantities of low-pressure polyethylene containers used for transportation and storage of oil products (motor oils) entail higher environmental risks produced by their utilization or disposal. An urgent scientific task is to search for new ways for utilization of such containers, to involve them in production of new target products without thorough cleaning of waste from contaminants and residues of motor oils. The present study involved crushed containers used for storage and transportation of motor oil in order to explore the possibility of including polyethylene in the production of asphalt concrete mixture. A sample, containing 17.5% of low-pressure polyethylene (contaminated with motor oil by 8% of asphalt mass), and a control sample of asphalt concrete mixture free of polyethylene, were made in order to investigate the change of properties, occurring in the low-pressure polyethylene asphalt concrete. Results. The study assessed main physical and mechanical properties of asphalt concrete samples containing low-pressure polyethylene and motor oil. According to the assessment, a number of properties exceed the values stated in GOST 9128-2013. In addition, the study results included development of technological regulations for producing asphalt concrete mixture with polyethylene as well as the flow diagram for obtaining asphalt concrete mixture. Using polyethylene waste contaminated with motor oil in the production cycle of asphalt concrete mixtures will reduce the consumption of raw materials for asphalt concrete production and the negative impact on the environment.

Application of spark plasma sintering to the manufacture of La2-xSrxCuO4 superconducting ceramics

To explore the possibility of improving the critical current density (Jc) of polycrystalline La1.84Sr0.16CuO4 (LSCO) superconductor ceramics, high density La1.84Sr0.16CuO4 samples have been prepared by means of spark plasma sintering (SPS). Structural and superconducting properties of samples made by different variations of the process have been measured for systematic comparison. The density of the SPS samples can reach up to 98 % of the theoretical density of LSCO, but the critical temperature (Tc) and critical current density (Jc) are suppressed by the process. Subsequent annealing has been applied to improve the properties of the SPS samples. After treatment at 1050 °C, in spite of partial decomposition that was observed on the surface of the samples, the Jc of LSCO was significantly improved. Detailed data as well as assumptions for explaining these results are provided. The SPS technique, coupled with a suitable post-annealing treatment is thereby appearing as a possible methodology to improve the critical current density of polycrystalline high temperature cuprate superconductors.

Experimental and simulation investigation on failure characteristic of granite considering the effect of intermediate principal stresses

This study performs one-sided lateral unloading- and three-way five-sided force-vertical continuous loading experiments with different intermediate principal stresses (IPS) to investigate the effect of the IPS on deformation, strength, failure modes, and acoustic emission (AE) signals of rock and to elucidate the role of the IPS on the rock strength. The inoculation, occurrence, development, and failure of rockburst as well as the AE evolution characteristics are discussed. The findings indicate that the rockburst ejection includes localized ejections of particles, spalling of rocks into plates, shearing of rocks into fragments, and ejections of rock fragments. The formation mechanism of rockburst involves three progressive processes, i.e., tensile, shear, and tensile-shear composite destruction. The peak stress of sample increases with increasing IPS, while the deformation modulus decreases exponentially as the unloading progresses. The sample properties under true triaxial unloading condition with different IPS can be described by the Mogi-Coulomb criterion. The evolution curves of ringing impact ratio (CH) and cumulative absolute energy can be divided into four stages. The crystal-scale refined model that considers mineral components efficiently simulate the rockburst. The simulated stress-strain (SS) curves of samples are in good agreement with those obtained from laboratory tests.

Synthesis, physical, optical, and transmission properties of terbium oxide-reinforced quinary borate glasses for radiation protection

This study explores the synthesis and characterization of borate glasses doped with varying concentrations of Terbium oxide (Tb4O7). Using the conventional melt-quench method, we investigated the effects of Tb4O7 on the physical, optical, gamma-ray shielding, and mechanical properties of the glass samples. Our findings indicate a significant increase in density with higher Tb4O7 content, attributed to the high molecular weight and density of Tb4O7. Optical properties assessed through UV–Vis spectroscopy revealed increased absorption intensity, a red shift in the absorption edge, and a decrease in the optical band gap, demonstrating enhanced optical absorption and refractive indices. Gamma-ray shielding effectiveness, evaluated using mass attenuation coefficients, half-value layers, and mean free paths, showed superior performance with higher Tb4O7 concentrations. The effective atomic number also increased, enhancing gamma-ray attenuation capabilities. Additionally, the elastic modulus of the glasses improved with higher Tb4O7 content, providing better mechanical stability. Our findings indicate that the density increased from 3.52 g/cm³ for undoped samples to 3.92 g/cm³ for the glass containing 2 mol% Tb4O7. Optical absorption measurements revealed a red shift in the absorption edge from 345.46 nm to 369.54 nm, with a corresponding decrease in the optical band gap from 3.48 eV to 3.18 eV. Gamma-ray shielding performance improved significantly, with the mass attenuation coefficient (GMAC) rising from 0.115 cm2/g to 0.162 cm2/g, while the half-value layer (GHVL) decreased from 3.22 cm to 2.86 cm. Additionally, the elastic modulus increased by 11.58 % as Tb4O7 content increased. These results suggest that Tb4O7-doped borate glasses significantly improve density, optical absorption, gamma-ray shielding, and mechanical strength. Finally, Increasing Tb4O7 content in borate glasses substantially enhances their multifunctional properties, making them suitable for advanced radiation shielding applications.

Improved gyromagnetic properties of LiZnTi ferrites co-fired with Bi2O3-La2O3 additives at low temperature

In this work, low temperature-sintered Li0.43Zn0.27Ti0.13Fe2.17O4 ferrites mixed with x wt.% (x = 0.00–0.30 wt%) of La2O3 and 1.5 wt% of Bi2O3 were successfully prepared by the solid-state reaction method. The variations in phase composition, microstructure, and gyromagnetic properties of the as-prepared samples were studied in detail. XRD patterns and refinement results show that La2O3 didn't affect the formation of the spinel phase, but a small amount of La3+ might enter into the lattice structure. The micro-morphological analysis and grain size statistics demonstrate that the addition of La2O3 significantly suppressed the grain growth, and the average grain size decreased from 2.19 μm (x = 0.00 wt%) to 1.14 μm (x = 0.15 wt%). The uniformity of the grain size distribution was improved, and the degree of densification was significantly increased. Meanwhile, the saturation magnetization (4πMs) increased from 3921 Gs to 3989 Gs, the coercivity (Hc) decreased from 457.5 A/m to 312.5 A/m, and the ferromagnetic resonance linewidth (ΔH) decreased from 328.5 Oe to 220.7 Oe. Our study indicates that the Bi2O3-La2O3 mixture is an effective sintering additive for low-temperature sintering of LiZnTi ferrite ceramics, which will play an important role in the development of low-temperature co-fired ferrites.