Experimental Investigation Of Physical Properties Research Articles

Experimental investigation of physical properties of homogenous and functionally graded glass fiber reinforced vinyl-ester composites

Experimental investigation of physical properties of homogenous and functionally graded glass fiber reinforced vinyl-ester composites

Experimental Investigations of Physical Properties of Iron-Copper Alloy

The paper describes the results of experiments aimed at obtaining iron-copper alloys with different iron content using electroslag remelting method. The obtained alloys of iron and copper were carefully examined to study their mechanical and physical properties. The article shows the results of the research work investigating the influence of iron on crystallization characteristics of the copper alloy. It was found, that iron-copper alloys can compete successfully with expensive copper-silver alloys, which are used to manufacture mold walls. The article offers the results of the experiments investigating hardness, wear resistance, thermal conductivity and temperature conductivity of the obtained iron-copper alloys; their casting characteristics were also studied.

Experimental investigation of physical properties and accelerated sunlight-healing performance of flake graphite and exfoliated graphite nanoplatelet modified asphalt materials

This presented research investigated the physical properties and accelerated sunlight-healing performance of graphite modified asphalt materials. Two types of graphite materials, flake graphite and exfoliated graphite nanoplatelets (xGNP), were added to asphalt with different contents by weight. Asphalt binder tests were conducted to evaluate the performance of modified asphalt, including rotational viscosity, light absorbance, and thermal conductivity. The tests results of graphite modified asphalt showed increased viscosities, decreased activation energies, and increased light absorbance and thermal conductivity in comparison to the control asphalt. Afterwards, the graphite modified asphalt mixture beams (5% flake graphite and 2% xGNP) were prepared and used for cyclic fracture-light healing tests. The digital image correlation (DIC) was utilized to characterize the displacement changes in the fracture zone during the light healing process. The DIC results indicated that the improved healing performance of graphite modified asphalt mixtures and decreased healing displacement with light healing cycles. Finally, the measured recovered strength after each cycle was used to evaluate the healing performance of both the graphite modified and control samples. The results of cyclic fracture-light healing tests indicated that the graphite modified asphalt materials have significantly improved healing performance and therefore these materials have promises in promoting new light healing applications.

Controllable Fabrication of Nanostructured Graphene Towards Electronics

Due to graphene's exceptional electronic properties, strong efforts are being made to push forward its nanoelectronic applications. However, the gapless band structure of truly 2D graphene makes it unsuitable for direct use in graphene‐based field‐effect transistors (FETs), which is one of the most widely discussed graphene applications in electronics. Therefore, in order to accomplish graphene's applications in semiconducting nanoelectronics, it is necessary to produce nanostructured graphene with sufficiently narrow characteristic width, thus introducing further confinement and opening a reasonably large band gap. In this article, the theoretical predictions of nanostructured graphene's various properties are briefly introduced, and then the recent progress in preparation methods are reviewed to make an objective appraisal in terms of narrow enough width and crystallographically determined edges based on the theoretical and experimental investigations of physical properties. Newly emerging nanostructured graphene arrays are also introduced, which are essential for the integration of devices. In addition, electronic devices based on graphene nanostructures or heterostructures, such as FETs and sensors, are also reviewed, including device construction and performance. This article is aimed at summarizing the most practical and efficient method oriented at a specific target and promoting the fundamental research and industrial applications of nanostructured graphene.

Evaluation of thermal and moisture management properties on knitted fabrics and comparison with a physiological model in warm conditions

This study reports on an experimental investigation of physical properties on the textile thermal comfort. Textile properties, such as thickness, relative porosity, air permeability, moisture regain, thermal conductivity, drying time and water-vapour transmission rate have been considered and correlated to the thermal and vapour resistance, permeability index, thermal effusivity and moisture management capability in order to determine the overall comfort performance of underwear fabrics. The results suggested that the fibre type, together with moisture regain and knitted structure characteristics appeared to affect some comfort-related properties of the fabrics. Additionally, thermal sensations, temperature and skin wetness predicted by Caseto ® software for three distinct activity levels were investigated. Results show that the data obtained from this model in transient state are correlated to the thermal conductivity for the temperature and to Ret, moisture regain and drying time for the skin wetness. This provides potential information to determine the end uses of these fabrics according to the selected activity level.

Towards graphene nanoribbon-based electronics

The successful fabrication of single layer graphene has greatly stimulated the progress of the research on graphene. In this article, focusing on the basic electronic and transport properties of graphene nanoribbons (GNRs), we review the recent progress of experimental fabrication of GNRs, and the theoretical and experimental investigations of physical properties and device applications of GNRs. We also briefly discuss the research efforts on the spin polarization of GNRs in relation to the edge states.

Magnetic phase transitions and electronic structure of the manganese silicides

The results of the experimental investigations of physical properties of the single crystals of Mn5Si3 and MnSi≈ l.7 doped by Ge and Cr are presented. For the first time an existence in Mn5Si3 the first order metamagnetic transition have been observed. From the experimental data it is found that the properties of the induced ferromagnetic state in Mn5Si3 and the doped higher manganese suicides can be interpreted on the basis of the band model. Theoretical calculations conclude that the band character of magnetism in Mn5Si3 is due to MnI atoms in 4(d) positions while atoms in 6(g) positions are covalent bonded and more localized.

Superparamagnetism in volcanic glasses of the KBS Tuff: Transmission electron microscopy and magnetic behavior

Volcanic glass separates (colorless to dark brown) from the KBS tuff of northern Kenya have been studied with a combination of transmission electron microscopy and low‐temperature ac susceptibility and dc magnetization experiments. The darker of these glasses exhibit classic superparamagnetic behavior, the origin of which lies in a spatially‐uniform precipitate of magnetite, which is present as ∼1% by weight in glass shards with the highest susceptibility. In any given glass separate (obtained by magnetic separation) this precipitate has a surprisingly narrow size distribution. A theory for the origin of the precipitate is nucleatation and growth in quenched glasses at temperatures of ∼1000‐1300°K; an experiment demonstrates the feasibility of this idea. These glasses provide us with a sample for experimental investigations of physical properties of naturally‐occurring dispersed magnetic phases at the lower limit of physical dimension that can be attained in the crystalline state.

Physical properties and electron spectrum of solid solutions (Co1?xNix)5Ge3

Data are presented from an experimental investigation of physical properties (paramagnetic susceptibility, electrical conductivity, Hall coefficient) and their temperature dependence in alloys (Co1−xNix)5Ge3, where 0≤x≤1, crystallized in the filled nickel arsenide type. Data obtained are used to define the zone structure of the electron energy spectrum in these crystals, which is based initially on theoretical group analysis with use of Goodenough's concept. It is shown that upon change in external parameters (electron concentration, temperature) shifting of zones relative to each other occurs.