Simulation of the Elastic Properties of Reinforced Kevlar-Graphene Composites

The compressive strength of unidirectional fiber composites in the form of Kevlar yarn with a thin outer layer of graphene was investigated and modeled. Such fiber structure may be fabricated by using a strong chemical bond between Kevlar yarn and graphene sheets. Chemical functionalization of graphene and Kevlar may achieved by modification of appropriate surface-bound functional (e.g., carboxylic acid) groups on their surfaces. In this report we studied elastic response to unidirectional in-plane applied load with load peaks along the diameter. The 2D linear elasticity model predicts that significant strengthening occurs when graphene outer layer radius is about 4 % of kevlar yarn radius. The polymer chains of Kevlar are linked into locally planar structure by hydrogen bonds across the chains, with transversal strength considerably weaker than longitudinal one. This suggests that introducing outer enveloping layer of graphene, linked to polymer chains by strong chemical bonds may significantly strengthen Kevlar fiber with respect to transversal deformations

Exclusive photoproduction of J/ψJ/\psi in proton-proton and proton-antiproton scattering

Protons and antiprotons at collider energies are a source of high energy Weizs\"acker--Williams photons. This may open a possibility to study exclusive photoproduction of heavy vector mesons at energies much larger than possible at the HERA accelerator. Here we present a detailed investigation of the exclusive $J/\psi$ photoproduction in proton-proton (RHIC, LHC) and proton-antiproton (Tevatron) collisions. We calculate several differential distributions in $t_1, t_2, y, \phi$, as well as transverse momentum distributions of $J/\Psi$'s. We discuss correlations in the azimuthal angle between outgoing protons or proton and antiproton as well as in the ($t_1, t_2$) space. Differently from electroproduction experiments, here both colliding beam particles can be a source of photons, and we find large interference terms in azimuthal angle distributions in a broad range of rapidities of the produced meson. We also include the spin--flip parts in the electromagnetic vertices. We discuss the effect of absorptive corrections on various distributions. Interestingly, absorption corrections induce a charge asymmetry in rapidity distributions, and are larger for $p p$ reactions than for the $p \bar p$ case. The reaction considered here constitutes an important nonreduceable background in recently proposed searches for odderon exchange.Comment: 22 pages, 20 figures; dedicated to Kolya Nikolaev on the occasion of his 60th birthday; 4 figures and discussion adde

Gravity Effect on Electrical Field Generation and Charge Carriers Transfer During Combustion Synthesis of Sulfides

The effect of gravity on the electric potential generated by the combustion synthesis of zinc sulfide is analyzed using the numerical simulation. Recent experimental studies on generation of electric voltage during combustion synthesis of zinc sulfide (ZnS) have revealed high voltage signals (4 V) with duration about 1 s, which are much higher than those produced by the gas–solid and solid–solid combustion reactions studied previously. These data have raised the question about mechanism of such a phenomenon. In our previous work we developed a novel (distributed) model describing the electric potential generation during combustion synthesis of sulfides (CSS) that didn\u27t count the effect of gravity. In this paper the simulations of heat - mass transfer, charge carriers motion, and voltage profiles taking into account the Earth gravity effect. The simulations confirms that the gravitation force strongly affects the emission of negatively charged sulfur ions as well as electrons and has a significant impact on the amplitude and temporal evolution of the combustion induced voltage. The voltage reduction up to four times has been observed numerically in the case when gravity acts in the direction coincident to that of the propagating combustion wave. Vice versa, the significant acceleration of the combustion and the voltage amplification due to the advection is simulated when gravity acts in the direction opposite to that of the propagating combustion wave

INVESTIGATION ON STABILITY OF TEXTILE MATERIALS FOR OVERALLS PROCESSED BY NEW BIOCIDAL PREPARATIONS

This article is devoted to the research of new promising biocidal preparations, in particular ethyl, allyl and methyl, which promote the improvement of the consumer properties of textile materials and increase their durability. The problem of protecting textile materials and products from microbiological destruction is complex and multifaceted, and its successful solution requires coordinated and focused efforts of specialists of various profiles. Of particular relevance is the search for effective ways to protect against microbiological destruction of textile materials. And today one of such methods of protection is to provide textiles with biocidal properties, which not only prevents the growth of bacteria, but can also provide a high level of wear resistance of tissues. The aim of the work was to study the impact of new low-toxic biocidal drugs on the stability of coloring of textile materials to the effect of various physical and chemical factors. In the research, the method and technology of providing biocidal properties to textile materials for the production of overalls, in particular, impregnation of textile materials in alcoholic solution of biocidal preparations, was developed. As samples were selected fabrics of different chemical composition, which are intended for the manufacture of overalls. The best results were obtained with dry friction, and, treatment, does not significantly affect the stability of color, and in the case of cotton-polyester fabric, on the contrary, even increases it. Low indicators of the stability of color to the action of wet friction is due to the low resistance of colors to water

The thickness of the ventricles and interventricular septum in males with overweight according to echocardiography

Introduction. Mortality from cardiovascular disease ranks first in the world. New and high requirements are required for the anatomical substantiation of emerging methods and methods of treatment. In modern literature, there are many publications on the issues of heart morphology, but data on the influence of gender, age, body weight on heart parameters are insufficient, fragmentary and often contradictory.Objective. To determine the thickness of the ventricles and interventricular septum in overweight men when performing echocardiography and to assess the presence or absence of the relationship of these parameters with age and body mass index (BMI) of the subjects. Patients and methods. The analysis of the protocols of ultrasound examination of the heart of 68 apparently healthy men of adolescence, the first and second periods of adulthood with a body mass index of 25.0–29.9 kg/m², with no pulmonary and cardiac pathology and the risk of cardiovascular diseases was carried out. Ultrasound examination was performed on an Aloka ProSound Alpha 6 ultrasound scanner. Results and discussion. When comparing the mean values of heart parameters in overweight men in three age groups according to the Kruskell – Wallis criterion, no statistically significant differences were found between the mean values (p > 0.05). Revealed a moderate strength relationship between the thickness of the anterior wall of the right ventricle with the age of the subject (r = 0.375; p = 0.020) and moderate strength relationship between the thickness of the posterior wall of the left ventricle and BMI (r = 0.352; p = 0.030).Conclusions. The  results of  the  study supplement the  information available in  the  scientific literature on the  thickness of  the  ventricles of  the  heart and the  interventricular septum in  healthy men with overweight in  three age groups. The data obtained will be useful to doctors of functional diagnostics when performing echocardiography in matters of differentiation between norm and pathology

Thickness of the ventricles and interventricular septum in men and women of the mesomorphic body type with normal body mass index according to echocardiography

The aim of the study was to establish the thickness of the ventricles and interventricular septum in individuals of the mesomorphic body type with a normal body mass index according to echocardiography and to assess the presence or absence of a relationship of these parameters with the gender and age of the subjects. Material and methods. The analysis of the protocols of ultrasound examination of the heart of 202 conditionally healthy persons of adolescence, the first and second periods of adulthood of the mesomorphic body type with a body mass index of 18.5–24.99 kg/m² was carried out. They have no pulmonary and cardiac pathology and risks of cardiovascular diseases. All subjects were divided into three age groups according to the age periodization of human ontogenesis (Moscow, 1965). Echocardiography was performed using a scanner Aloka ProSound Alpha 6. Results. The thicknesses of the anterior wall of the right ventricle, the posterior wall of the left ventricle, and the interventricular septum in women of the second period of adulthood is greater, than in young girl and women of the first period of adulthood (p ˂ 0.05); the thickness of the interventricular septum in men of the second period of adulthood is greater, than in young men and men of the first period of adulthood (p ˂ 0.05). It has been established that the thickness of the anterior wall of the right ventricle and interventricular septum depends on person gender: it is greater in men. In women, moderate correlation was found between the thickness of both the left ventricle (r = 0.425; p < 0.001) and the right (r = 0.411; p < 0.001) with age. A direct relationship (moderate strength) of the thickness of the interventricular septum with age (r = 0.331; p = 0.014) was found in men. Conclusion. The results of this morphological study supplement the information available in the scientific literature on the thickness of the ventricles of the heart and interventricular septum in a conditionally healthy person of the mesomorphic body type with a normal body mass index

Amaranth oil application for coronary heart disease and hypertension

Cardiovascular disease (CVD) is the Nation's leading killer for both men and women among all racial and ethnic groups. Development and progression of CVD is linked to the presence of risk factors such as hyperlipidemia, hypertension, obesity, and diabetes mellitus. It is known that cholesterol is an indicator of increased risk of heart attack and stroke. Low-density cholesterol (LDL) above 130 mg/dl high-density cholesterol (HDL) cholesterol below 35 mg/dl and total blood cholesterol above 200 mg/dl are indicators of problematic cholesterol. Proper ranges of cholesterol are important in the prevention of CVD. It has been suggested that a reduction in the consumption of saturated and an increase in unsaturated fatty acids is beneficial and prevents CVD. Amaranth grain contains tocotrienols and squalene compounds, which are known to affect cholesterol biosynthesis. The cholesterol precursors squalene, lanosterol and other methyl sterols, reflect cholesterol synthesis [1-3], whereas plant sterols and cholestanol, a metabolite of cholesterol, reflect the efficiency of cholesterol absorption in normal and hyperlipidemic populations [4-6]. Qureshi with co-authors [7] showed that feeding of chickens with amaranth oil decreases blood cholesterol levels, which are supported by the work of others [8]. Previously, we have shown that Amaranth oil modulates the cell membrane fluidity [9] and stabilized membranes that could be one reason as to why it is beneficial to those who consume it. It is known that in hypertension, the cell membrane is defective and hence, the movement of the Na and K ions across the cell membranes could defective that could contribute to the development of increase in blood pressure. Based on these properties of amaranth oil we hypothesize that it could be of significant benefit for patients with CVD

Researches of fractional composition of protein of Amaranth

It is widely known that Amaranth is a highly nutritious plant, and contains all the essential amino acids. It provides an amazing amount of magnesium, calcium and dietary fiber for general health. The literature provides that there are numerous citations about the quality and composition of amaranth seeds, but not much information about amaranth protein in the green mass. Furthermore, amaranth's green mass has a fast and high yield, making it a great source of protein. For this reason, the protein amount, as well as fractional composition in different kind of amaranth, was investigated. It was revealed that amaranth differs in its content of protein, with its maximal accumulation in the blossoming phase (17.2-32.6% from dry weight for various samples), within various species. It was confirmed that in the ontogenesis of amaranth, the share of albumins and globulins is reduced while the share of glutelins and gliadins is increased. A low content of reserved proteins in the seeds of amaranth (42% from the sum of protein) in comparison with wheat and other cereals has been observed. © 2008 Bentham Science Publishers Ltd