Магнитный импеданс пленочных наноструктур для оценки полей рассеяния микрочастиц магнитных композитов

Longitudinal giant magnetoimpedance effect of [Fe21Ni79/Cu]5/Cu/[Fe21Ni79/Cu]5 film element was investigated depends on stray magnetic field of epoxy magnetic composite with 30 % weight concentration of iron oxide magnetic microparticles. Configuration of an experiment was a model of thrombus detection in a blood vessel. Stray magnetic field was varied by movement of a magnetic composite above the element perpendicular to the long side. Composite was either magnetized or not to the state of remanence. As the magnetic composite approaches the GMI element, MI ratio curves are smoothed and shifted along the field axis and maximum value of the MI ratio decreases. Magnetic properties of magnetic composite and film element were investigated as well.

Measurement and study of thermophysical properties of nanofluids with carbon nanotubes

This article is devoted to the study of the thermophysical properties of nanofluids with single-walled and multi-walled carbon nanotubes (CNT). Their weight concentration varied from 0.05 to 0.2%. Nanofluids, based on ethylene glycol and water, were studied. Dispersants were also used. The diffusion of CNT had been systematically investigated by the method of dynamic light scattering and their effective hydrodynamic dimensions were determined. The rheology and viscosity of all nanofluids were studied. It is shown that nanofluids are either pseu-doplastic or viscoplastic. Their rheology changes with increasing CNT concentration and temperature. However, in all cases, the viscosity of nanofluids with single-walled CNTs is signifi-cantly higher than that of nanofluids with multi-walled CNTs. In the last part, the electrical conductivity of all these nanofluids and the dispersants effect on it are investigated.

Study of the component composition of organic matter of the East Pre-Caucasian basin rocks based on the results of lithological, petrophysical and geochemical studies

This study introduces results of lithological, petrophysical and geochemical investigation of Lower Cretaceous (K1) and Middle Jurassic (J2a-b) rocks of East Pre-Caucasian basin. According to pyrolytic and bituminological studies method of separate determination of kerogen and bitumen concentration been developed. In accordance with this method differentiation of organic matter components in different lithotypes of rocks been described. Also relationship between bitumen and kerogen concentrations been revealed. The majority of samples have poor to fair organic richness and poor source potential. Kerogen type is commonly presented by type III and stages of maturity characterized by stages PC3 to MC3. Bitumen compounds have low concentrations of asphaltenes and aromatic hydrocarbons and mainly contains light and heavy resins. Based on petrophysical and geochemical studies a close relationship between the concentration of organic carbon and the weight concentration of potassium nuclides was obtained. This relationship indicates that kerogen in the sediments under consideration is associated with clay minerals, which is also confirmed by the mineral composition of the rocks.

DIRECT-INK-WRITING (DIW) OF HIGHER WEIGHT CONCENTRATION OF MILLED CARBON FIBER (MCF) REINFORCED EPOXY COMPOSITE

Additive manufacturing or 3D printing of short carbon fiber composites is highly inclined toward thermoplastic material. Recently, there is some interest in developing 3D printing technology for thermosetting polymers and composites. Direct-ink-writing (DIW) of short fiber epoxy composites containing milled carbon fibers (MCF) exhibits the potential to replace the traditional composite material as it showcases the inherent capability of fabricating complex geometries, facile material processing, continuous printing capability coupled with low cost. Previous research in 3D printing of short carbon fiber epoxy composites suffered heavily from the limitation of printing low carbon fiber weight concentrations. This study developed a straightforward technique of designing the epoxy ink containing high weight concentration MCF (~40wt%) and a small concentration of thixotropic filler (3-wt%) for DIW using a pneumatic pressure-driven extruder having micron size tapered nozzle. This paper also intends to contribute to a better understanding of the effect of printing parameters on DIW. Furthermore, the printing parameters were optimized using non-dimensionalized constant C. Optimized printing condition was further used to print different geometry ranging from dog bone with 100% infill to 4-layer hollow circle and 3-layer hollow square with 0% infill. Lastly, ink exhibits the capability to self-support multi-layer geometrical structures during printing.

PBAT Based Composites Reinforced with Microcrystalline Cellulose Obtained from Softwood Almond Shells

This study explores the processability, mechanical, and thermal properties of biocompostable composites based on poly (butylene adipate-co-terephthalate) (PBAT) as polymer matrix and microcrystalline cellulose (MCC) derived from softwood almond (Prunus dulcis) shells (as-MCC) as filler at two different weight concentration, i.e., 10 wt% and 20 wt%. The materials were processed by melt mixing and a commercial MCC (c-MCC) was used as filler comparison. The fibrillar shape of as-MCC particles was found to change the rheological behavior of PBAT, particularly at the highest concentration. The melt mixing processing allowed obtaining a uniform dispersion of both kinds of fillers, slightly reducing the L/D ratio of as-MCC fibers. The as-MCC particles led to a higher increase of the elastic modulus of PBAT if compared to the c-MCC counterparts. Both the MCC fillers caused a drastic reduction of the elongation at break, although it was higher than 120% also at the highest filler concentrations. DSC analysis revealed that both MCC fillers poorly affected the matrix crystallinity, although as-MCC induced a slight PBAT crystallinity increase from 8.8% up to 10.9% for PBAT/as-MCC 20%. Therefore, this work demonstrates the great potential of MCC particles derived from almond shells as filler for biocompostable composites fabrication.

Scientific Evidences of the "Prostration Effect" on the Forehead of Some Prayer

Prostration, putting forehead on the ground or clay-tablet, has many medical benefits. But some reports showed on the forehead of a few prayers it causes prostration effect/PE or clay-tablet effect/CTE, as a skin-callosity, on his/her forehead. This effect, which in Persian language is named Mohr-e-Pishani, has always been a curious question for researchers. Observation of the PE raises many questions in mind, which is not limited to the present time. For example; in old books 'Ali Ibn Al Husayn, Zainul Abedeen (PBUH), the fourth Imam of the Shia, has been nicknamed "Zol-Seqqnat" for having the CTE on his forehead which in the Arabic language means “the owner of skin-callosity”. The main purpose of this study was to uncover the scientific evidence of the PE on the forehead of some prayers. The results showed that several factors would result the development of PE, including physiological factors such as skin structure and its keratin content; allergens of the ground and soil as an external factor including chemical elements, acidity, macromolecules, and microorganisms. Physical factors, such as the way and duration of prostration, head weight concentration on the ground, soil or clay-tablet are also effective. These findings can answer some of the questions, curiosities, and possible doubts related to the phenomenon of PE or CTE on the forehead as a phenotype for other researches.

Lipid and carotenoid production by Rhodosporodium toruloides ATCC 204091 using C5 and C6 sugars obtained from lignocellulosic hydrolysate

Aim: This study investigated the production of lipids and carotenoids and associated growth properties by the oleaginous red yeast Rhodosporodium toruloides strain ATCC 204091, using C5 and C6 sugar streams of lignocellulosic waste hydrolysate separately and in combination (C5+C6). Methodology: Cell density, wet and dry biomass weight, concentration of total sugars and reducing sugars were determined at various time intervals during cell growth in media containing C5, C6 and mixed sugars. Lipid and carotenoids were extracted and the media were compared with respect to production. Results: Production of lipid (22.25%) and carotenoids (19 mg l-1) was highest in C6 sugar, as compared to mixed sugars and C5 sugar. Interpretation: Due to the versatility of Rhodosporodium toruloides strain ATCC 204091 for utilizing C6 and C5 sugars present in waste hydrolysates, it has been projected as a good choice for cultivation in “waste” hydrolysates.

Median Polish Kriging and Sequential Gaussian Simulation for the Spatial Analysis of Source Rock Data

In this technical note, a geostatistical model was applied to explore the spatial distribution of source rock data in terms of total organic carbon weight concentration. The median polish kriging method was used to approximate the “row and column effect” in the generated array data, in order for the ordinary kriging methodology to be applied by means of the residuals. Moreover, the sequential Gaussian simulation was employed to quantify the uncertainty of the estimates. The modified Box–Cox technique was applied to normalize the residuals and a cross-validation analysis was performed to evaluate the efficiency of the method. A map of the spatial distribution of total organic carbon weight concentration was constructed along with the 5% and 95% confidence intervals. This work encourages the use of the median polish kriging method for similar applications.

Characterizing Biaxially Stretched Polypropylene / Graphene Nanoplatelet Composites

In this work, polypropylene (PP) nanocomposites containing different weight concentration of graphene nanoplatelets (GNP) were prepared by melt-mixing using an industrial-scale, co-rotating, intermeshing, twin-screw extruder. The materials were then compression moulded into sheets, and biaxially stretched at different stretching ratios (SRs) below the PP melting temperature. The effects of GNP content and biaxial stretching on the bulk properties of unfilled PP and PP/GNP nanocomposites have been investigated in details. Results show that the addition of GNP (>5wt%) can lead to electrically conductive composites due to the formation of percolation network. The GNP have led to increased polymer crystallinity and enhanced materials stiffness and strength. Biaxial stretching process further enhances the materials mechanical properties but has slightly decreased the composites electrical conductivity. The PP/GNP nanocomposites were also processed into 3D demonstrator parts using vacuum forming, and the properties of which were comparable with biaxially stretched composites.

In vitro biocompatibility study of microwave absorbing conducting polymer blend films for biomedical applications

In the present communication, microwave absorbing property in the frequency range of 12.4–18 GHz and in vitro biocompatibility studies of light weight, flexible, biocompatible, and environment friendly polymer blend films of polyvinylchloride (PVC)-polyvinylpyrrolidone (PVP) (taken in ratio 1:1) and doped with various percentage weight concentration of polypyrrole (PPy) are reported. Addition of PPy in the PVC-PVP matrix exhibited a synergetic effect in improving microwave absorbing property. PVC-PVP blend film with 40 and 50% concentrations of PPy were seen to absorb microwaves of the order of 28–50 dB in ku band of microwave region indicating that this composition can suitably find application as microwave absorbing material. In vitro biocompatibility skin irritation study of PVC-PVP (taken in ratio 1:1) with 50% weight concentration of PPy indicated that the prepared film did not have any irritation upon administration and hence is safe for topical application. Moreover, the blood compatibility study of this film exhibited compatibility with blood and can safely be used in any blood contacting mask/device. Hence, this biocompatible film can potentially be used as microwave absorbing material for masking some parts of human body or can be interfaced to biological systems or devices.