This article describes calculations of the yield ratio of anti-particles to the yield of particles (
/
p
,
/
d
,
/
3
He) in proton–proton and nuclear–nuclear interactions using the self-similarity ...parameter in the central rapidity region. The used approach is based on the study of relativistic nuclear interactions in the four-velocity space. The results of the calculations are compared with the existing experimental data in a wide center-of-mass energy range (
SPS
,
RHIC
,
LHC
). Within this approach the inclusive spectra of pions and kaons and ratios of their yields in pp collisions have been successfully described earlier.
This paper describes a method of modelling a curvilinear reinforcement structure, for a composite plate with a hole that allows trajectories of fibres to be adapted to geometric discontinuities ...(holes, notches, bolts, etc.). For this method, it is assumed that the trajectories of fibres are curvilinear and continuous, as well as located along the trajectories of maximum principal stress. On the basis of these trajectories, the functionally graded material is simulated by means of the finite element method (FEM). Each element of this structure has its own mechanical properties, depending on the fibre direction and a change in the distance between the fibres. It is demonstrated that the maximum value of the stress concentration factor in the fibre direction for the plate with the curvilinear reinforcement structure reduces by 3.2times in comparison with the same plate with a rectilinear reinforcement structure (orthotropic material).
Automation and using robotic means allows increasing industry efficiency, including construction. At the same time, important factors of applying such means are profitability and adaptability. The ...paper considers the basic parameters influencing the economic and technological efficiency of applying mobile bricklaying robots. The main aspects for comparing manual and automated labor are showed based on the acting standards and technical features of operation of such robots. It is offered to use a coefficient showing the ratio of brickwork volumes for bearing walls and for partitions of a constructed object for evaluation of efficiency of applying a bricklaying robot. As most buildings differ from each other, the modeling software for automated evaluation economic and technological parameters of construction is offered. Such software will include a model of operation of a bricklaying robot and will evaluate efficiency of different combinations of manual and automated labor during bricklaying.
Curved continuous fiber trajectories for composite plates with a bolted joint corresponding to the lines of maximum principal stresses were designed using the iterative finite-element modeling. On ...their basis, variable stiffness composite structures were modeled by the finite-element method, when each element was assigned variable material properties depending on the distribution of fiber trajectories. To simulate the progressive failure of the plates, a material property degradation method was employed. An analysis of progressive failure showed that it is possible to significantly increase the ultimate load and reliability of bolted joints of composite structural elements by transition from the unidirectional to a curvilinear reinforcement.
This study is devoted to obtaining long-length two-layer corrosion-resistant tube blanks by explosion welding for their subsequent rolling into tubing. The technological scheme of the process was ...developed, which allowed ensuring high-quality adhesion of the internal corrosion-resistant layer from austenitic stainless steel 08Kh18N10T with a tube blank made of 37G2F hollow structural steel. In the course of study on the experimental production of bimetallic pipes of 2.4 meters in length, the following problems were solved: 1) the choice of optimal collision regimes of the tube elements thrown on each other; 2) the development of the necessary technological equipment to maintain the alignment of the main elements; 3) ensuring full filling of the internal surface of the device with solid-liquid filler without contact with the welding gap (sealing with welded joints); 4) reducing the degree of lateral dispersion of the explosive due to the assembly enhancing in the ground and use a metal formwork; 5) estimation of the relative narrowing of the outer diameter of the bimetallic tube after explosion welding; 6) carrying out ultrasonic control of the continuity of connection of the obtained two-layer pipes in order to reveal the mistreatment zones along the length of the blanks.
It is well recognized that obesity increases the risk of various cancers, including breast malignancies in postmenopausal women. Furthermore, obesity may adversely affect tumor progression, ...metastasis, and overall prognosis in both pre- and postmenopausal women with breast cancer. However, the precise mechanism(s) through which obesity acts is/are still elusive and this relationship has been the subject of much investigation and speculation. Recently, adipose tissue and its associated cytokine-like proteins, adipokines, particularly leptin and adiponectin, have been investigated as mediators for the association of obesity with breast cancer. Higher circulating levels of leptin found in obese subjects could be a growth-enhancing factor as supported by
in vitro
and preclinical studies, whereas low adiponectin levels in obese women may be permissive for leptin’s growth-promoting effects. These speculations are supported by
in vitro
studies which indicate that leptin promotes human breast cancer cell proliferation while adiponectin exhibits anti-proliferative actions. Further, estrogen and its receptors have a definite impact on the response of human breast cancer cell lines to leptin and adiponectin. More in-depth studies are needed to provide additional and precise links between the
in vivo
development of breast cancer and the balance of adiponectin and leptin.
•LEND/LRO instrument neutron counting data sets have been analyzed to create high resolution maps of epithermal neutron flux at polar regions of the Moon.•The conversion from epithermal neutron flux ...to the H/H2O abundances is presented based on the simple subsurface models.•The polar lunar maps (poleward 70S/70N) of homogeneous hydrogen distribution are derived and discussed.
We present a method of conversion of the lunar neutron counting rate measured by the Lunar Reconnaissance Orbiter (LRO) Lunar Exploration Neutron Detector (LEND) instrument collimated neutron detectors, to water equivalent hydrogen (WEH) in the top ∼1m layer of lunar regolith. Polar maps of the Moon's inferred hydrogen abundance are presented and discussed.
Passive autocatalytic recombiners (PARs) are used for the removal of accidentally released hydrogen inside confined spaces. The high catalyst surface temperature is an important safety issue to be ...considered in the use of a PAR. The ability to predict the catalyst surface temperature could be very useful in preventing the self-ignition and explosion of hydrogen inside the PAR. This study seeks to investigate the changes in temperature profiles of the PAR catalytic section upon variation of the inlet hydrogen concentration. Experiments were conducted on a small-scale test setup. The catalytic section comprised cylindrical ceramic elements arranged in parallel and held upright by a stainless-steel frame. The temperature profiles were measured with a high-resolution infrared camera. The commercial computational fluid dynamics (CFD) code STAR-CCM+ was used as a numerical tool for modeling the gas mixture flow inside the experimental setup and the chemical reaction kinetics. The results of numerical studies are presented and compared with experimental results. The presented CFD-based approach and software offer an appropriate numerical tool for the investigation of hydrogen safety issues. Finally, the catalyst was subjected to a prolonged high-temperature combustion fatigue procedure to determine its stability. The surface of the fatigued catalyst was evaluated by scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was found that decomposition of the protective surface layer occurred at elevated temperatures; the catalytic activity was unaffected by this. In addition, a relatively uniform reactive metal particle size was maintained over the entire temperature range, suggesting that no aggregation occurred.
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