Support Columns Research Articles

Design of broadband dual-polarized antenna with integrated Marchand balun

A design of broadband dual-polarized antenna with low cross polarization and high isolation was presented. The antenna is composed of a cross dipole, a folded ground, two feeding networks, and a reflector. The impedance bandwidth was enhanced by utilizing the mutual coupling between the two dipoles. A kind of meandering folded Marchand balun was skillfully integrated on the support column of the antenna to excite the dipole differentially, which can deliver both balanced (within 0.5 dB) power splitting and consistent (±5°) phase shifting from 1.71 GHz to 2.17 GHz. The standing wave ratios (SWRs) of each port are less than 1.5. By using this feeding network, the antenna has good performance in isolation (> 45 dB) and cross polarization (> 30 dB) over the entire operating frequency band. Moreover, the gain (∼8.6 dB) of the proposed antenna is stable with frequency and the antenna structure is very firm due to the support column. The proposed antenna can be easily formed an array for digital cellular system (DCS), personal communications service (PCS) and 3rd generation (3G) applications.

On the Effectiveness of Two Isolation Systems for the Seismic Protection of Elevated Tanks

This paper deals with the effectiveness of two isolation systems for the seismic protection of elevated steel storage tanks. In particular, the performance of high damping rubber bearings (HDRB) and friction pendulum isolators (FPS) has been analyzed. As case study, an emblematic example of elevated tanks collapsed during the Koaceli Earthquake in 1999 at Habas pharmaceutics plant in Turkey is considered. A time-history analysis conducted using lumped mass models demonstrates the high demand in terms of base shear required to the support columns and their inevitable collapse due to the insufficient shear strength. A proper design of HDRB and FPS isolator according to the EN1998 and a complete nonlinear analysis of the isolated tanks proved the high effectiveness of both isolation systems in reducing the response of the case tank. Actually, the stability conditions imposed by the code and a reduced level of convective base shear obtained with the second isolation typology suggests the use of FPS isolators rather than HDRB devices.

Development of CFD methodology for investigating thermal-hydraulic characteristics in a PWR dome

This study aims to develop a detailed computational fluid dynamics (CFD) model to investigate the flow and heat transfer characteristics in the dome of a pressurized water reactor (PWR). The upper plenum is also considered in order to simulate the possible coolant leak to the dome via the gaps of upper support plate. The essential solid components within the solution domain, including the upper core plate, the guide tube assemblies, the support columns, and the rod cluster control, are realistically modeled, instead of the porous-medium approximation. Through the detailed-geometry CFD simulation, the thermal-hydraulic features in the upper plenum, individual guide tube assembly, and the dome can be obtained. And, the temperature distribution on the reactor pressure vessel (RPV) head can be used to estimate the values of total effective degradation years (EDY) and reinspection years (RIY) for monitoring the crack initiation and growth on the head. Present calculated results also reveal that the original values of EDY and RIY using the cold-leg temperature as the head temperature by the Maanshan staff is conservative.

Finite Element Analysis of the Displacement Adjustment Scheme for Column Bases of a 10000 m3 Spherical Tank During Whole-body Heat Treatment

The stress of spherical tank and displacement of column bases were calculated by finite element method, considering the uneven gravity loads on support columns which was caused by manufacturing and setting errors. The preliminary displacement adjustment scheme for column bases was made, according to the safety range of column bases displacement which was determined by the maximum stress restricted by allowable stress at the set heat treatment temperatures. The final scheme was made after checking the preliminary scheme. The method of making adjustment scheme of column bases for a 10000m3 spherical tank during the whole-body heat treatment may provide a reference for other large spherical tank.

The forensic medical evaluation of the injuries to the cervical spine in the driver and the front-seat passenger of a modern motor vehicle after the frontal crash

The objective of the present study was to elucidate the specific features of the lesions of the cervical spine in the driver and the front-seat passenger of a modern car after the frontal crash. We made use of the archival materials of forensic medical expertises concerning the traffic accidents carried out in the city of Moscow during the period from 2005 to 2012. The study was focused on the analysis of the character of the fractures of cervical vertebrae in the drivers (n = 55) and the front-seat passengers (n = 85) of a modern motor vehicle involved in a traffic accident. It was shown that the drivers most frequently suffer bending-extension fractures of the cervical vertebrae, with the II-IV vertebrae being especially frequently subject to multiple fractures resulting in the damage to the anterior support column, sometimes to both the anterior and posterior columns, and much rarer to the posterior column. The front-seat passengers also suffer bending-extension fractures. The IV-VI vertebrae are most frequently affected in them with isolated damages to either the anterior or the posterior support column of the neck vertebrae.

Non – Invasive GPR Investigation of Spread Footings

A non-invasive GPR survey was carried out in order to investigate spread footings of reinforced concrete skeleton building with basement. The GPR survey was performed in 2D geometry around support columns using a ground coupled antenna with central frequency of 400MHz. The processed data allow very detailed interpretation of spread footings. This type of geophysical survey confirms its suitability and usability in such non – invasive investigation.

LOWER LIMB REHABILITATION ROBOT FOR GAIT TRAINING

After analyzing the rehabilitation needs of stroke patients and the previous studies on lower limb rehabilitation robot, our lower limb rehabilitation robot is designed for stroke patients' gait and balance training. The robot consists of the mobile chassis, the support column and the pelvis mechanism and it is described in detail. As the pelvis mechanism allows most of the patient's motion degrees of freedom (DOFs), the kinematics model of the mechanism is set up, and kinematics simulation is carried out to study the motion characteristics of the mechanism. After analyzing the calculation and simulation results, the pelvis mechanism is proven to measure up to the movement needs of the paralytic's waist and pelvis in walking rehabilitation process.

Seismic vulnerability assessment of a high voltage disconnect switch

This paper deals with the seismic vulnerability of high voltage equipment typically installed in electric substations. In particular, the seismic response of a 380kV vertical disconnect switch has been investigated based on the results of an experimental campaign carried out at Roma Tre University. According to a series of non-linear analyses, the influence of the most significant parameters on the seismic behavior of this apparatus has been analyzed and the corresponding fragility curves have been evaluated by using the Effective Fragility Analysis method. The results showed a limited vulnerability of the disconnect switch, whose most critical parts are the bottom joint of the ceramic support column and the steel column base.

The Finite Element Analysis of Lei-Ring Applied to Upright Column for Hydraulic Support

Abstract:In this paper ,the finite element model of the lei-ring was established in ANSYS software,the sealing performance of hydraulic support column piston was analyzed.Also,the numerical simulation analysis was made of the impact of column working pressure on the sealing performance,and a series of the integrated equivalent stress and contact pressure images of sealing ring when working were got. From those images,the location most prone to failure can be concluded.All of work can provide a theoretical reference for the design and use of drum sealing ring used on hydraulic support upright column.

Pressures on the support columns buried in iron ore stockpiles

This paper presents the results of experimental investigations aimed at the determination of the loads exerted on support structures buried in gravity reclaim stockpiles. Structures, such as trestle legs to support load-out conveyors in open stockpiles, or columns to support roof structures and load-out conveyors of enclosed bulk solids storage sheds are subject to the loads exerted by the surrounding bulk solids. The complexity of these loads has been discussed recently (Roberts, 2007 [1], Katterfeld and Roberts, 2009 [2]). According to the theoretical approach proposed by Roberts, both active and passive stress states in bulk solids contribute considerably to the pressure distributions on these support columns. The findings of the preliminary experimental studies carried out by Roberts match with the theoretical predictions. However, follow-up work is required to further validate and improve the design equations for the determination of the loads on support columns. Based on Roberts' prediction model, a laboratory scale test rig was constructed to measure the loads on both the front and rear faces of a buried column. Tekscan tactile pressure sensors were employed in the pressure measurements. Stockpile tests under three different conditions were investigated, and the measured results correlate well with theoretical predictions from modified Roberts' theory. The outcome confirms that Roberts' theory can contribute to the design criterion regarding the loads on buried structures in stockpiles.

A reliable and rapid method for soluble sugars and RFO analysis in chickpea using HPAEC–PAD and its comparison with HPLC–RI

A high performance anion exchange chromatography (HPAEC) coupled with pulsed amperometric detection (PAD) was optimised to separate with precision, accuracy and high reproducibility soluble sugars including oligosaccharides present in pulse meal samples. The optimised method within 20min separated myo-inositol, galactinol, glucose, fructose, sucrose, raffinose, stachyose and verbascose in chickpea seed meal extracts. Gradient method of eluting solvent (sodium hydroxide) resulted in higher sensitivity and rapid detection compared to similar analytical methods. Peaks asymmetry equivalent to one and resolution value ⩾1.5 support column’s precision and accuracy for quantitative determinations of soluble sugars in complex mixtures. Intermediate precision determined as relative standard deviation (1.8–3.5%) for different soluble sugars confirms reproducibility of the optimised method. The developed method has superior sensitivity to detect even scarcely present verbascose in chickpea. It also quantifies myo-inositol and galactinol making it suitable both for RFO related genotype screening and biosynthetic studies.

CFD Analysis of the Coolant Mixing within the Upper Plenum of a Pressurized Water Reactor (PWR)

In this study, a Computational Fluid Dynamic (CFD) model is established to obtain the 3-D flow characteristic, temperature distribution of the pressurized water reactor (PWR) upper plenum and hot-legs. In the CFD model, the flow domain includes the upper plenum, the 61 control rod guide tubes, the 40 support columns, the three hot-legs. The inlet boundary located at the exit of the reactor core and the outlet boundary is set at the hot-leg pipes several meters away from upper plenum. The temperature and flow distribution at the inlet boundary are given by sub-channel codes. The computational mesh used in the present work is polyhedron element and a mesh sensitivity study is performed. The RANS equations for incompressible flow is solved with a Realizable k-ε turbulence model using the commercial CFD code STAR-CCM+. The analysis results show that the flow field of the upper plenum is very complex and the temperature distribution at inlet boundary have significant impact to the coolant mixing in the upper plenum as well as the hot-legs. The detailed coolant mixing patterns are important references to design the reactor core fuel management and the internal structure in upper plenum.

CFD Analysis of the Coolant Mixing within the Upper Plenum of a Pressurized Water Reactor (PWR)

In this study, a Computational Fluid Dynamic (CFD) model is established to obtain the 3-D flow characteristic, temperature distribution of the pressurized water reactor (PWR) upper plenum and hot-legs. In the CFD model, the flow domain includes the upper plenum, the 61 control rod guide tubes, the 40 support columns, the three hot-legs. The inlet boundary located at the exit of the reactor core and the outlet boundary is set at the hot-leg pipes several meters away from upper plenum. The temperature and flow distribution at the inlet boundary are given by sub-channel codes. The computational mesh used in the present work is polyhedron element and a mesh sensitivity study is performed. The RANS equations for incompressible flow is solved with a Realizable k-ε turbulence model using the commercial CFD code STAR-CCM+. The analysis results show that the flow field of the upper plenum is very complex and the temperature distribution at inlet boundary have significant impact to the coolant mixing in the upper plenum as well as the hot-legs. The detailed coolant mixing patterns are important references to design the reactor core fuel management and the internal structure in upper plenum.

Buckling Mode Jump at Very Close Load Values in Unattached Flat-End Columns: Theory and Experiment

Buckling of compressed flat-end columns loaded by unattached flat platens is shown, theoretically and experimentally, to occur first at the critical load and associated mode shape of a built-in column, followed extremely closely by a second critical load and different mode shape characterized by column end tilt. The theoretical critical load for secondary or end tilt buckling for a column geometry tested is shown to be only 0.13% greater than the critical load for primary buckling, in which the ends are in full contact with the compression platens. The experimental value is consistent with this theoretical one. Interestingly, under displacement control, the first buckling instability is characterized by a smoothly increasing applied load, whereas the closely following second instability causes an abrupt and large load drop (and hence exhibits incremental negative stiffness). The end tilt buckling gives rise to large hysteresis that can be useful in structural damping but that is nonconservative and potentially catastrophic in the context of design of structural support columns.

The Improved Design of Machine Tool Structure Based on Sensitivity Analysis

The machine tool bed is an important component of the center. The function is components of support column, worktable and so on. The machining accuracy can be influenced by the function machine tool bed. To establish the finite element model of horizontal machining center by Solid works. And the first six orders modal can be analyzed by Ansys. The dynamic sensitivity analysis is used to determine the parameters of stiffened plate by sensitivity optimization method. The better structure parameters can be getting by making a structural optimization design for the analysis. Finally, the dynamic characteristics and function of the machine tool bed can be improved.

Design Application of LQS20000 Column Strength Test Bench

Analyzed the trend of the development of hydraulic powered support and column, this paper designs a column strength test bench with 20000KN working resistance which combined with the new release of GB25974.2-2010 for coal mine hydraulic support and jack technical conditions of Part 2 standard requirements. Through the practical application, it turned out that the test bench has reasonable structure, stable performance and it can meet all of the following Ф630 bore hydraulic support column factory test requirements. The trend of the mine-used hydraulic support column and the performed new criterion demands manufacturers to enhance the ability of test equipment. In this situation, the 20000KN column strength test bench our company designed and manufactured not only do the loading test, but also apply external load at columns by simulating the actual working conditions, which is essential to Inspection and testing of dual-extension hydraulic columns middle cylinder strength.

The Finite Element Analysis of Y Seal Ring for Hydraulic Support Column

In order to understand its performance before seal ring putting into use, the paper selects the commonly used polyurethane Y-sealing ring, establishes a model of Y-ring using finite element analysis software and simulates the work environment of seal ring. The deformation and stress of Y-ring under various working pressure can be obtained to summary the deformation and stress rules, as well as the possible crack positions of Y-ring.

LONG-TERM RESULTS OF ANTERIOR SPINAL FUSION WITH VASCULARIZED RIB GRAFT FOR SEVERE KYPHOSCOLIOSIS IN NEUROFIBROMATOSIS

The paper presents results of long-term (12 and 18 years) follow- up after the treatment of two patients with severe kyphoscoliosis in neurofibromatosis type 1 who underwent anterior spinal fusion with application of pedicled vascularized rib autograft. Surgery provided the graft convertion into a regenerate having a form of a support column. At the final follow-up a correction of hyperkyphosis was maintained in both cases, and scoliosis progressed in one patient.

Simulation Research on Hydraulic Support Column System Based on AMESim

The working principle and process of the hydraulic support column system is introduced at first. The simulation model of the column system is established in the software of AMESim, and the parameters of the model are set according to the actual working conditions. The simulation curves of each working procedure are obtained, and the simulation results are analyzed. The conclusions will be essential references for the research on the entire support hydraulic system.

Cyclic behaviour of bolted cold-formed steel moment connections: FE modelling including slip

In this paper a Finite Element (FE) procedure is described for simulating hysteretic moment–rotation behaviour and failure deformations of bolted cold-formed steel (CFS) moment connections. One of the main challenges in modelling the response of bolted connections is the presence of bolt slip. A series of six beam–column assemblies comprising CFS curved flange beams, a support column and a through plate were tested under cyclic loading. The moment–rotation behaviour of the connections was dominated either by flexure in the beams or by bolt slip in the connections. FE models presented in this paper incorporate geometrical imperfections of the beams, material properties obtained from tensile coupon tests and bolt slip to address these two types of behaviour. The updated FE models result in an accurate prediction of the hysteretic moment–rotation behaviour of the connections dominated by a flexural behaviour in the beams. A simplified cyclic slip model which allows slip at a specified reduced slip resistance load simulates reasonably well the hysteretic behaviour of connections dominated by bolt slip. Using the updated FE model, the failure modes of the connections predicted by the simulations also agree well with those observed in the experiments.