Characteristic Of Material Research Articles

Timurid, Ottoman, Safavid and Qajar Ceramics: Raman and Composition Classification of the Different Types of Glaze and Pigments

Raw materials significantly determine the final composition and properties of a fired ceramic. Raman analysis which characterizes micro- and nanostructures of (coloured) glazes, opacified or not, was applied to shards mostly collected before the 1960s, currently at the Louvre Museum, originated in Anatolia, the Caucasus, Iran and Central Asia, which are, for most of them, characterized by the use of black lines to separate coloured areas, and dated to the period between the 12th and 19th centuries. Measurements were carried out in the laboratory with a blue laser excitation and/or on the conservation site with a mobile device (green laser). Three types of glazes were identified by their nanostructure of the silicate network: (i) a lead-rich glaze analogous to that of Byzantine, Zirid to Hafsid and al-Andalus productions, (ii) a lead-alkali glaze typical of the Ottoman productions of Iznik-Kütahya, and (iii) a mixed (poor lead/lead-free)-alkali glaze typical of Safavid productions. The colour determines the precise composition of the glaze. The identification is not only based on the signature of the stretching mode of the SiO4 tetrahedron (position of the wavenumber of the component(s)) but also on the position and shape of the continuous luminescence of the Raman background, characteristic of the raw materials used. Lead-tin yellow, Fe-rich, Mn-rich and Cr-rich black pigments and opacifiers made of cassiterite and wollastonite were also identified. The results (type of glaze and deduced processing temperature) were discussed in the light of the ternary phase diagrams visualizing elemental composition determined in previous works and the microstructure examination on the polished section (defining single or multistep firing cycles). Continuity was highlighted on the one hand between the tiles of Bursa, Edirne and Istanbul (Ottoman Iznik-like production) and on the other hand between those of Samarkand area (Timurid) and Iran. The procedure was then applied in the study of three objects (two dishes and a bowl) which are very representative of the productions of the Turkish-Persian cultural areas: a polychrome mina’i cup with decoration representing a rider, an Ottoman Iznik fritware with polychrome floral decoration, and a blue-and-white Safavid ceramic with a decoration representing a shrub.

On the Stability Testing of Reference Materials

The present article presents comparative characteristics of domestic and international approaches to estimating the instability of reference materials, and describes the proposed changes in R50.2.031-2003. A mathematical apparatus and an algorithm of actions for estimating the standard uncertainty due to instability, and the shelf life of a reference material are proposed. Approaches to estimating the uncertainty due to instability in the cases of absence and presence of a significant trend in the certified characteristic of a reference material over time are considered. It is shown that there is a rationale for the minimum number of measurements to study the stability of a reference material. It has been established that the smoothing of the measurement results when estimating the stability of a reference material leads to the appointment of an overestimated shelf life.

Production of activated carbon from exhausted coffee grounds chemically modified with natural eucalyptus ash lye and its use in the fluoride adsorption process.

The objective of this research was to produce an activated carbon (AC) from exhausted coffee grounds (ECG) and chemically activate it with natural lye from eucalyptus ash to subsequently evaluate the fluoride adsorption process in an aqueous medium. The thermal analysis of ECG was determined as well as solubilized extraction, alkalinity and calcium content of eucalyptus ashes. AC was characterized by elemental analysis, scanning electron microscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), analysis of textural properties, pH and point of zero charge (PZC). The AC presented macroporosity and XRD confirmed the amorphous characteristic of cellulose-containing materials. Carboxylic acid functional group was identified in the AC surface, which can contribute to the adsorption of fluoride. The specific surface area of ECG and AC were 189.01 and 21.74 m2/g. The adsorption kinetics of fluoride revealed that equilibrium is reached around 800min and the data followed the pseudo-second order model. The Freundlich model fitted the experimental data with the best quality and Freundlich's constant n allowed inferring that the adsorption is favorable and the isotherm appears to be L-type, with an initial downward curvature, which suggests less availability of active sites when increasing the adsorbent concentration.

Material Characteristic of an Innovative Stent for the Treatment of Urethral Stenosis

Abstract The appropriate development and customisation of the stent to the urethral tissues requires the determination of many factors such as strength and degradation. Given the distinctive conditions of urethral tissues, it is important that the design of the stent be properly developed. The selection of a stent material requires knowing its material characteristics and verifying that they are suitable for the future implantation site. In the present study, the development of a polydioxanone (PDO)-based stent was undertaken. The PDO material was fabricated using an additive technique – 3D printing. Then, in vitro tests were performed to determine the degradation time of the material under conditions simulating an aggressive urinary environment. The changes in the parameters of mechanical properties before and after the degradation period were determined, and the changes in the structure of the material before and after degradation were observed. Numerical analysis was performed for the proposed stent design. The results showed that PDO has good mechanical properties, but its degradation time is too short to be used in a urethral stent. Among the innovations of the studies conducted are bending strength tests, which is not a frequently considered aspect so far.

PENGEMBANGAN BAHAN AJAR MATEMATIKA PADA MATERI PROGRAM LINEAR DENGAN MODEL PROBLEM-BASED LEARNING UNTUK MENINGKATKAN KEMAMPUAN PEMAHAMAN MATEMATIS SISWA SMA

This research supported by the lack of student’s mathematical understanding ability, and the need for the development of linear programming material for students.The purposes of this research are: to describe the characteristics of linear programming material written with problem-based learning model, and assess the quality of material considered from validity, practicality, and effectiveness.The research used quantitative and qualitative approaches, with research and development method, in form of Dick and Carey’s design. Research was conducted at one of senior high school in Bandung. The instruments used are: validation’s sheets, the mathematical understanding test, observation sheets, and questionnaire. According to the data processing and analysis of the development of material, researcher have two conclusions. The first conclusion, characteristic of material developed was: based on the curriculum 2013 standard with a KI-1 not specified in teaching materials and some KI-2 not all included in material, the presentation of material developed according to a problem-based learning model, and equipped with a problem, examples, exercise about, and evaluate compiled based on an indicator of mathematical understanding ability. The second conclusions, instruction materials developed was valid, practical, and effective.

Experimental study on the interface bonding characteristic of polyurethane and pavement materials

As a new grouting material, polyurethane has been used in the repair engineering of longitudinal joint distress of semi-rigid base asphalt pavement. It is necessary to study the bonding characteristics of the interface between polyurethane and road materials. In this paper, the interface characteristics of composite materials were considered from the two materials about pavement material and base material. Shear test and split tensile test were carried out on the specimens with different interface roughness and polyurethane density. Based on the test data, the strength models of shear strength and splitting tensile strength with roughness and density were established. The micro-characteristics of the composite interface were analyzed. Polyurethane formed a dense film at the interface, and the film thickness increases with the increase of density. The failure mode of the specimen was affected by the polyurethane film. In addition, the influence of normal stress is considered in the shear test, and the friction angle of the interface was analyzed. The stress-strain curve characteristics of shear test and split tensile test of two kinds of composite materials were summarized. The failure modes were generally three types: failure along the boundary of polyurethane material, failure along the boundary of base material, and joint failure of polyurethane material and base material along the interface. The research results provide a basis for better understanding the influencing factors and failure modes of the bonding characteristic between asphalt mixture, cement stabilized macadam and polyurethane materials.

Surface Physicochemical Properties of Smectite‐Rich Fault Gouge: A Case Study of the Japan Trench Plate‐Boundary Fault

AbstractThe frontal part of the Japan Trench plate‐boundary fault is enriched in low‐strength smectite, and this material characteristic is thought to be a factor for the large fault slip during the 2011 Mw 9.0 Tohoku‐oki earthquake. In this study, we evaluated the surface physicochemical properties of the particles that constitute the fault zone and examined their effect on the rheological properties of the fault. Measurements of the zeta potential, surface free energy and pore size distribution indicate that the interparticle interaction in the in situ state is very weak. This means that the viscous resistance is low, which may have contributed to the large fault slip during the earthquake. The interparticle distance appears be longer than the energetically stable state, which may reflect a transitory state after the earthquake. Changes in microscopic interparticle interactions during coseismic and interseismic periods may influence the rheological behaviors of the Japan Trench plate‐boundary fault.

Effect of filling configurations on melting heat transfer characteristic of phase change materials partially filled with metal foam

Metal foam embedded in phase change materials (PCM) has been shown to significantly improve the storage of latent heat thermal energy. Nonetheless the presence of metal foam also reduces natural convection, energy storage and increases cost. To address this issue, we modelled the internal flow of heat transfer in a PCM, paraffin wax, filled with metal foam at the top or the bottom, with filling height ratio ξ of 0.25, 0.5 and 0.75. The liquid-solid phase transition was studied by numerical simulations. Results show that natural convection in the pure paraffin wax area is higher, and melting time is shorter, in the bottom-filled than in the top-filled configuration. These differences increase with filling height ratio. By contrast, in metal foam-paraffin composite region, melting time is longer in the bottom-filled configuration due to heat loss. Interestingly, we observed significant changes in the interface shape of liquid-solid PCM at the junction of the pure paraffin and the metal foam-paraffin composite region. The liquid fraction formulas for different metal foam filled configurations are established as the function of Fourier number, Rayleigh number and filling height ratio.

Thermal Stability and Kinetics of Degradation of Moxonidine as Pure Ingredient vs. Pharmaceutical Formulation

The stability of active pharmaceutical ingredients (APIs) and the corresponding pharmaceutical formulations are nowadays of great importance in pharmaceutical research and technology. The quality of an API or of finished pharmaceutical products (FPPs) is time dependent under the influence of several parameters, such as light and air exposure, temperature, and humidity. Additionally, the stability profile of an API is influenced by the formulation composition, due to the presence of excipients or by the characteristic of the packaging materials. In this sense, the main objective of this study was to analyze the degradation kinetics of the antihypertensive drug moxonidine as a pure ingredient (MOX) and in two different solid mixtures, one corresponding to a pharmaceutical formulation (MOXTAB) and the other to an enriched pharmaceutical formulation in MOX (MOXMIX). As investigation techniques, FTIR (Fourier transform infrared) spectroscopy and TG/DTG/HF analysis were employed, while the thermoanalytical data were processed according to the ASTM E698 kinetic method and the isoconversional methods of Flynn–Wall–Ozawa (FWO) and Friedman (FR). The kinetic methods revealed that the excipients have a stabilizing effect on MOX (in terms of Ea values), but the decomposition mechanism of the samples is complex, according to the results suggested by the analysis of Ea vs. α values.

Research on ignition and reaction characteristic of PTFE-based reactive materials

In order to study the ignition characteristic of PTFE-based reactive materials (RMs), Al/W/PTFE RMs with different W powder contents were prepared and split Hopkinson pressure bar (SHPB) test was carried out under different loading conditions. The temperature rise of three RMs were calculated theoretically. The material model parameters of the three formulations were calculated by using the mixture equation of state theory and Johnson-cook model, and the impact process was numerically simulated by using AUTODYN dynamics software. The results showed that the Al/PTFE (26.5/73.5) formula material has ignition reaction when the impact speed is 27.47m/s, and Al/W/PTFE (7.94/45.33/46.73) formula material is 28.68m/s. Al/W/PTFE (5.29/80/14.71) only has weak ignition reaction under experimental conditions. The ignition reaction of RMs is related to the impact temperature rise. Under the impact condition, local high temperature induced ignition occurred at the crack of RMs.With the increase of W powder content, the overall temperature rise of RMs decreased, and the reaction degree of RMs decreased.

The influence of elliptic aspect ratio and inclination angle on the melting characteristic of phase change material in concentric cylindrical enclosure

The influence of elliptic aspect ratio and inclination angle on the melting characteristic of phase change material in concentric cylindrical enclosure

Effect of Addition of Oleic Acid as a Template with Tetraethylorthosilicate (TEOS) as Source of Silica on Porosity Mesoporous Silica Material

Mesoporous silica material has been synthesized using tetraethylorthosilicate (TEOS) as a source of silica, oleic acid as a template, and 3-aminopropyltrimethoxysilane (APMS) as co-structure directing agents (CSDA). The synthesis of silica material was made with a variation in the mole ratio of TEOS: Oleic acid with a ratio of 1: 0.2; 1: 0.3; 1: 0.5; 1: 0.6; 1: 0.7; 1: 0.9, and 1: 1. A mixture between TEOS and APMS was added to a mixture of oleic acid, HCl 0.1N and demineralized water then stirred at room temperature for 2 hours. Then aging, the mix at 80oC for 48 hours until solids are formed. Product separation was used in the centrifugation method. The resulting solid was dried at 50oC, and to remove the template, calcined at 550oC for 6 hours. The product of XRD analysis has a wider diffraction peak that indicates an amorphous material. The FT-IR spectrum shows the Si-OH and Si-O-Si groups which area characteristic of silica material. The product of SEM analysis offers the presence of sheets and plates of particle forms with different sizes. Adsorption desorption isotherm (BET) shows an isotherm type IV curve, and dominant pore sizes are 1.945 and 4.588 nm.

SORS Performance of Sublayer Materials with Different Optical Properties under Diffuse Scattering Media

Over the past few years, the utilization of spatially offset Raman spectroscopy (SORS) has significantly evolved in its ability to analyze layered turbid materials non-invasively. It is well known that SORS can effectively detect the deeper layer in a high scattering media, and the performance characteristics of SORS have been extensively studied. However, to date, there is a lack of detailed studies of SORS to detect materials with different optical properties. This study aims to fill this gap by constructing a simple bilayer model, in which a target material with different optical properties was covered with a diffuse scattering barrier. By analyzing the Raman intensity from both superficial barriers and underlying target materials, we investigated the SORS performance to probe three typical optical materials with distinct optical properties: strong absorption, high transparency, and strong scattering. It was found that SORS technology can readily detect the samples of different properties under turbid surface coverings, and the typical optical property of the sublayer materials provided a specific SORS feature. Our study demonstrates the great potential of SORS technology for the non-invasive detection of subcutaneous component applications and provides a comprehensive understanding of the SORS characteristic of various materials.

Numerical Investigation on the Ballistic Performance of Semi-Cylindrical Nacre-like Composite Shells under High-Velocity Impact.

The nacre has excellent impact resistance performance, and it is attracting attention in the field of aerospace composite research. Inspired by the layered structure from nacre, semi-cylindrical nacre-like composite shells of brittle silicon carbide ceramic (SiC) and aluminum (AA5083-H116) were established. Two types of tablet arrangements (regular hexagonal and Voronoi polygons) of the composites were designed, and the same size of ceramic and aluminum shell were established for the impact resistance analyzed numerically. In order to better compare the resistance performance of the four types of structures under different impact velocity, the following parameters were analyzed including energy variation, damage characteristic, bullet residual velocity, and semi-cylindrical shell displacement. The results show that the semi-cylindrical ceramic shells have higher rigidity and ballistic limit, but the severe vibration after impact causes penetrating cracks, and the whole structure failure occurred eventually. The nacre-like composites have higher ballistic limits than semi-cylindrical aluminum shells, and the impact of bullets only causes local failure. In the same conditions, the impact resistance of regular hexagons is better than Voronoi polygons. The research analyzes the resistance characteristic of nacre-like composites and single materials, and provides a reference for the design of nacre-like structures.

Electrical switching of ferro-rotational order in nanometre-thick 1T-TaS2 crystals.

Hysteretic switching of domain states is a salient characteristic of all ferroic materials and the foundation for their multifunctional applications. Ferro-rotational order is emerging as a type of ferroic order that features structural rotations, but control over state switching remains elusive due to its invariance under both time reversal and spatial inversion. Here we demonstrate electrical switching of ferro-rotational domain states in the charge-density-wave phases of nanometre-thick 1T-TaS2 crystals. Cooling from the high-symmetry phase to the ferro-rotational phase under an external electric field induces domain state switching and domain wall formation, which is realized in a simple two-terminal configuration using a volt-scale bias. Although the electric field does not couple with the order due to symmetry mismatch, it drives domain wall propagation to give rise to reversible, durable and non-volatile isothermal state switching at room temperature. These results offer a route to the manipulation of ferro-rotational order and its nanoelectronic applications.

Construction of EG/SiOC@C porous structure by direct ink writing and in-situ vapor self - Deposition to enhance microwave absorption

In this work, expanded graphite (EG) was dispersed inside modified polysiloxane resin and successfully printed various cellular structures with span feature via ultraviolet-thermal field co-assisted direct ink writing. The carbon-rich layer was in-situ deposited in the designed porous structure surface by no gas flow pyrolysis process. The characterization of Raman and X-ray photoelectron spectroscopy indicate that the deposited cladding structure possessed amounts of sp2-C, and mainly bonds to the matrix in the manner of Si–C. The presence of cladding structure played a vital role in enhancing the electric conductivity and interface polarization, resulting in excellent microwave absorption performance. The addition of expanded graphite also improved the dielectric property by reinforcing the internal interfacial polarization and achieving a good impedance matching. Finally, the structure reached a minimum reflection loss of −59.31 dB at the thickness of 2.8 mm, and a broadband absorption of 4.2 GHz in the X-band (8.2–12.4 GHz) at 3.1 mm, covering the whole X band. The novelty strategy of controlling the surface state by pyrolysis vapor self-deposition can open a new avenue to tailor the functional characteristic of materials, especially on the assist of direct ink writing which can easy realize complex structural geometry on-demand.

Is Soft Carbon a More Suitable Match for SiOx in Li-Ion Battery Anodes?

Silicon oxide (SiOx ), inheriting the high-capacity characteristic of silicon-based materials but possessing superior cycling stability, is a promising anode material for next-generation Li-ion batteries. SiOx is typically applied in combination with graphite (Gr), but the limited cycling durability of the SiOx /Gr composites curtails large-scale applications. In this work, this limited durability is demonstrated in part related to the presence of a bidirectional diffusion at the SiOx /Gr interface, which is driven by their intrinsic working potential differences and the concentration gradients. When Li on the Li-rich surface of SiOx is captured by Gr, the SiOx surface shrinks, hindering further lithiation. The use of soft carbon (SC) instead of Gr can prevent such instability is further demonstrated. The higher working potential of SC avoids bidirectional diffusion and surface compression thus allowing further lithiation. In this scenario, the evolution of the Li concentration gradient in SiOx conforms to its spontaneous lithiation process, benefiting the electrochemical performance. These results highlight the focus on the working potential of carbon as a strategy for rational optimization of SiOx /C composites toward improved battery performance.

The Elastic Properties of Objects by Determining Young's Modulus for the Characterization of Metal Raw Materials Using a Speed Sensor Encoder and a Load Cell Sensor

The unique characteristic of a metal material can be determined from the value of Young's modulus which represents the ability of the material to deform in response to an external force given to the material. This study aims to determine the value of Young's modulus for three metal wires (copper, nickel, and steel) and the percentage of measurement errors using a self-designed Young's modulus kit equipped with a load cell sensor and speed sensor encoder. The measurement of Young's modulus was carried out in five experiments without any variation in diameter (the diameter was fixed and the same for all metals), and the results were compared with the reference values. The results showed that the values of Young's modulus for copper, nickel, and steel wires were 11.74 x 1010 N/m2, 21.63 x 1010 N/m2, and 20.84 x 1010 N/m2, respectively. The difference between the measured values and the reference values for Young's modulus for copper, nickel, and steel wires were 6.7%, 3.0%, and 4.18%, respectively. The small differences between the measured values and the reference values indicate that the measurement approach approximates the reference values and can be used to support other measurements involving Young's modulus values of a metal material

Thermodynamic properties and superstatistics analysis of particle in the non-relativistic system under the influence of trigonometric scarf potential using Dong proper quantization

There has been an intense study on the eigenvalue and eigenfunction of the nonrelativistic quantum system. The Schrodinger equation is important in the nonrelativistic quantum system that is used to analyze the quantum information of the system, so it attached the interest of the researchers to conduct the exploration on it. In most of the studies, the researchers expand the study of the solution of the Schrodinger equation to the physical properties of the system. The thermodynamical property is one of the physical properties and key to analyzing the characteristic of materials. It needs more investigation since it has the potential to form a new design of the material. In this study, the Schrodinger equation with trigonometric Scarf potential was solved using the Supersymmetry WKB quantization condition scheme, where the variable of trigonometric Scarf potential was transformed into the Poschl-Teller potential. The energy spectra were obtained by comparing the constant parameters between Trigonometric Scarf potential and Poschl-Teller potential and by using Dong proper quantization condition of transformed Supersymmetry WKB for trigonometric Scarf potential. The result shows that the energy spectra are influenced by the radial quantum number and the potential width, and the energy increase by the increase of the radial quantum number and the potential width. The thermodynamic properties of the system were obtained approximately using the energy spectra equation and were expressed in the erf function. The superstatistics mechanics was approximately obtained by using modified Delta Dirac function distribution for the Boltzmann factor. These properties are important to analyze the characteristic of the designed solids.

ZnO Production from EAF Solid Waste Using Hydrothermal Methods via Oxalate Precipitation

Electric Arc Furnace (EAF) waste contains 50-60% Zn. EAF waste synthesis has the potential to produce ZnO, which can be used in a variety of applications. The hydrothermal method is used in the synthesis, with time variations of 3 and 6 hours and temperature variations of 120 °C, 150 °C and 200 °C using precipitating reagents in the form of sodium hydroxide (NaOH) and oxalic acid (C2H2O4). UV-Vis spectrophotometer characterization result shows the absorbance value at 365 nm, which is the absorbance characteristic of ZnO material. The result of increasing the Zn element was revealed by XRF characterization. The XRD characterization revealed zinc oxalate dehydrates. This result depicts the hydrothermal with the oxalic acid solvent used to produce zinc oxalate dehydration at various temperatures and time variations.