Papers by Keyword: Cross-Section

Abstract: The present investigation focuses on the response of simply supported reinforced concrete rectangular-section beams with multiple openings of different sizes, numbers, and geometrical configurations. The advantages of the reinforcement concrete beams with multiple opening are mainly, practical benefit including decreasing the floor heights due to passage of the utilities through the beam rather than the passage beneath it, and constructional benefit that includes the reduction of the self-weight of structure resulting due to the reduction of the dead load that achieves economic design. To optimize beam self-weight with its ultimate resistance capacity, ten reinforced concrete beams having a length, width, and depth of 2700, 100, and 400 mm, respectively were fabricated and tested as simply supported beams under one incremental concentrated load at mid-span until failure. The design parameters were the configuration and size of openings. Three main groups categorized experimental beams comprise the same area of openings and steel reinforcement details but differ in configurations. Three different shapes of openings were considered, mainly, rectangular, parallelogram, and circular. The experimental results indicate that, the beams with circular openings more efficient than the other configurations in ultimate load capacity and beams stiffness whereas, the beams with parallelogram openings were better than the beams with rectangular openings. Commonly, it was observed that the reduction in ultimate load capacity, for beams of group I, II, and III compared to the reference solid beam ranged between (75 to 93%), (65 to 93%), and (70 to 79%) respectively.

Abstract: Interaction of molybdenyl(VI) bis(acetylacetonate) with polyphenylsiloxane in xylene and under mechanochemical activation conditions has been investigated. The interaction of the above reagents under mechanical activation conditions proceeds with formation of soluble polymers similar to those obtained in a solution with the silicon/molybdenum ratio equal to 2.6. The crystal chemistry parameters of the fraction obtained in solution with the ratio Si/Mo = 1:2 have been calculated on the basis of the X-ray diffraction analysis data using the Debye–Shearer equation. It has been demonstrated that the chain cross-section found using the Miller–Boyer method coincides with that calculated geometrically on the basis of literature data on bond lengths and angles.

Abstract: The study deals with the calculation of the wear rate of nanocrystalline diamond (NCD) films. The NCD films were grown by microwave plasma enhanced chemical vapor deposition (MW-PECVD) on (100)-oriented Si wafers. Reciprocating sliding tests with different loads and test durations were conducted. The depth profiles of wear scars were analyzed by the mechanical (stylus) profilometer and the wear rate was evaluated. The NCD films were broken across the wear scars and the wear rate was estimated by the measurement of the area of wear scar using the scanning electron microscopy (SEM) cross-sectional image. A good agreement was found between two methods.

Abstract: The most comfortable way to present capacity is M-N interaction curve diagram (bending moment and longitudinal force). Graph of M-N most commonly appears as a function, where an axial force is the argument and the bending moment is the value. This work introduce a formation of the curve way, where the the rotation angle of the strain diagram is the argument, and the full strain diagram is the value. Using the complete state of the strain of the cross section, enables easy calculation the M-N forces using stress-strain diagram for a given material. Interaction graph is based on parabola-rectangle diagram for concrete and the graph with inclined top branch with strain limit for reinforcing steel. The method has no restrictions due to the concrete class.

Abstract: The aim of this paper is to determine values of strains, while using the assumptions required in calculation of reinforced concrete beam cross sections according to general method included in EN-1992-1-1. It is related to application of the parabolic rectangular diagram of stresses in concrete. Various types of strain analysis were carried out using derived formulas and script written by K. Kamiński in MS Excel. A high sensitivity to changes of reinforcement area has been noticed while carrying out the analysis with the same assumptions as in the calculation of cross sections according to general requirements included in EC2. It has been found out, that the reason of this sensitivity is related to the applied design values in strain-stress relations. Other approach to the strain analysis has been suggested. The main assumption of this approach is related to using characteristic values of material parameters. Finally, both: the calculations of necessary reinforcement area and strain analysis assuming characteristic values of concrete compressive strength and yield strength of steel gained in satisfactory results conformity for area of reinforcement calculated in simplified and non‑simplified method according to EN-1992-1-1.

Abstract: In this paper the SEE (single event effects) of different parts of device were explored on a 32-bit microprocessor with a five-stage instruction pipeline by laser test and heavy ion test. The cross section curves for different function units were obtained and the comparison of the dates obtained from laser test and heavy ion tests was made. In addition, laser test under different scanning steps were made which indicate that when the scanning step length is in small steps which is considerably equivalent to the laser spot size, there is little change in the number of single event errors caused by each laser pulse. Wherever with the scanning step increasing, the number of single event errors caused by each laser pulse will be reduced. Experiment results suggest that there are differences between laser test and the heavy ion test but have a similar trend. The pulsed laser is an extremely powerful and low-cost technique for SEE testing and will provide invaluable information in characterizing SEE in integrate circuits.

Abstract: In this article, impact of cross-section and size on vibration of silicon nanowires is simulated by the molecular dynamics method based on molecular dynamics software Material Studio. The comparison of fundamental frequencies of the silicon nanowires with triangle, diamond, and hexagon cross sections is carried out. The orientations of these silicon nanowires are all in <111> direction. Then we change the length and the width of silicon nanowires to investigate the impact of size on vibration of silicon nanowires. The results show that with the influence of surface effect, the vibration frequency of silicon nanowires strongly depends on cross-section and size.

Abstract: This paper mainly introduces the variable cross-section rotary dynamic seal, sealing mechanism, research and development, listing examples of variable cross-section rotary dynamic seal applied in the petroleum machinery. Due to its simple structure, reliable sealing performance, it is widely applied to the occasions such as high pressure, in suffering much, shock vibration.

Abstract: Afterthe construction of subway main structure, in order to realize route adjustmentof alignment and gradient, it needs to survey the cross-section of subwaytunnel. Compared with conventional measuring methods, 3D laser scanning has thecharacteristics of non-contact measurement and can collect space 3D point clouddata with high density, this can improve the working efficiency for the subwaycross-section surveying. Based on the Leica Scanstation 2 scanners this paperanalyzed the 3D laser scanning point cloud data collection procedures and dataprocessing, expounded the subway cross-section surveying method based on pointcloud data; analyzed the feasibility of 3D laser scanning technology in theapplication of tunnel cross-section surveying based on the field validationdata. The results show that the cross-section measured by this method can meetthe technical requirements of route adjustment of alignment and gradient.

Abstract: A steel concrete lining is today the common ground massive retaining structure implemented shortly after the excavation of an opening. The constituent elements of the steel concrete lining are layers of shotcrete and steel arch frames. This simple structure has many unique features which set it apart from the conventional reinforced concrete constructions. Without simplification these features doesn’t allow to carry out design and evaluation of steel concrete lining by relevant design and evaluation methods convenient to the conventional reinforced concrete constructions. The main differences are construction process, yielding curve of structure and determination of external load. In the case of a steel concrete lining its external load is product of mutual work of both the ground massive and the lining. The value of load depends on the yielding curves of the lining and the ground massive. The yielding curve of a ground massive is objective and conditioned on strength strain properties of ground massive and primary stress state. The yielding curve of a steel concrete lining relates lining design specification. The process of construction affects the value of load too. The article analyzes the steel concrete lining focusing the influence of lining design parameters on its yielding curve. It looks for a way to control the ground massive behavior and as well as to engage it more in an effort with lining to stabilize subterranean work. The themes of the analysis are: static and deformation parameters of the cross-section of the steel concrete lining with regard to the construction stage and dependency of hardening shotcrete; interaction between of steel concrete lining and ground massive based on yielding curves; assessment of a stress state across the steel concrete lining section in the steel concrete lining constituent elements. The analysis is carried out on mathematical models that combine analytical and numerical methods.