Diagonal Cross Research Articles

Quasi-static cyclic performance of RC exterior beam-column joint assemblages strengthened with geosynthetic materials

The beam-column joints are the most critical and vulnerable part of the RC framed structures when subjected to earthquake load. The objective of the present study is to investigate the cyclic behaviour of seismic and non-seismic exterior reinforced concrete (RC) beam-column joints strengthened with innovative polymeric based geosynthetic materials. Two variants of geosynthetic material named geogrid and geotextile were used for strengthening the beam-column joints in the experimental program. In this strengthening protocol, two different types of strengthening patterns were used in which one was horizontal U-shaped pattern, and the other one was the diagonal cross (X-shaped) pattern. All the beam-column specimens were tested under the quasi-static cyclic loading with controlled amplitude to explore the cyclic performance on the parameters such as failure modes, hysteresis loops, load-deformation envelope curves, ductility, energy dissipation capacity, stiffness and strength degradation behaviour, pinching width ratio, damage index and joint distortion. The test results showed that the adopted strengthening schemes with geotextile and geogrid materials could successfully alter the failure of beam-column joints from shear to flexural and improved the ductile behaviour of the strengthened specimens. The load-carrying capacity and ductility-factor of the geosynthetic strengthened specimens significantly increased up to 48.4% and 37.8%, respectively when compared to the non-seismic control specimen, and it was highest in geogrid strengthened BCJs, especially in diagonal X-shape bonded specimen. The significant increment of energy dissipation capacity was also observed as 2.08 to 3.73 times for the strengthened specimens. Furthermore, the post-elastic performance and the joint shear strength of strengthened RC beam-column joints was also improved in comparison to the non-seismic control specimen. In addition, an analytical study was carried out to predict the shear strength contributions of externally bonded strengthening materials in the RC beam-column joint, which was compared with experimental findings. A good agreement was observed between the analytical and experimental results. Hence, the experimental and analytical study of the strengthened beam-column joints using geotextile and geogrid have confirmed that the appropriate bonding of these materials to the concrete can improve the seismic performance of the non-seismic exterior RC beam-column joints.

SafeDrive: A New Model for Driving Risk Analysis Based on Crash Avoidance

Driving risk evaluation is a critical issue in driving safety analysis. In traditional driving risk evaluation models, vehicles are analyzed as isolated units. Nevertheless, vehicles are surrounded by other vehicles during driving in a real setting, and therefore, the driving patterns of target vehicles are inevitably affected by surrounding vehicles. In this paper, we proposed a new driving risk evaluation model incorporating the driving patterns of the target vehicle, the driving patterns of surrounding vehicles, and the interactions between the target vehicle and surrounding vehicles to improve driving safety in situations like car-following and merging situations. According to experiments on real data, our proposed method outperformed the state-of-the-art methods by at least 14.2% in terms of precision. Our work verified that factors like the driving patterns of surrounding vehicles and the interactions between a target vehicle and surrounding vehicles can enhance the performance of driving risk evaluation. The experimental results also showed that the driving patterns of surrounding vehicles in different positions vary in evaluating the driving risk of the target vehicle. More specifically, the surrounding vehicles in cross positions casted the strongest influence, followed by the surrounding vehicles in the diagonal cross positions. In summary, our study provided a novel way to enhance driving risk evaluation performance for driving safety improvement.

Clonal diversity and genetic variation of the sedge Carex nigra in an alpine fen depend on soil nutrients.

In this study we analysed the impact of water regime and soil nutrients on the clonal diversity and genetic variation of the sedge Carex nigra in a central alpine fen. For our analysis, we established 16 study plots randomly distributed over the fen. We determined the exact elevation of each plot as an indicator for the water regime and measured the content of phosphorous and potassium in the soil of each plot. Clonal diversity and genetic variation of C. nigra were assessed with nuclear microsatellites using leaf material collected in 20 subplots along a diagonal cross within each study plot. The influence of water regime and soil mineral nutrients on clonal diversity and genetic variation was estimated by Bayesian multiple regression. Our study revealed a clear impact of soil nutrient conditions on clonal diversity and genetic variation of C. nigra, which increased with the concentration of phosphorous and decreased with the concentration of potassium. Key background to these findings seems to be the relative offspring success from generative as compared to clonal propagation. Phosphorous acquisition is essential during seedling establishment. Clonal diversity and genetic variation increase, therefore, at sites with higher phosphorous contents due to more successful recruitment. High levels of clonal diversity and genetic variation at sites of low potassium availability may in contrast be mainly caused by increased plant susceptibility to abiotic stress under conditions of potassium deficiency, which brings about more gaps in C. nigra stands and favors the ingrowth from other clones or recruitment from seeds.

VLSI based orthogonal diagonal cross hair search (ODCHS) algorithm implementation for efficient image compression

In this paper, an efficient image codec is proposed using Magnetic Resonance Images (MRI). During the past few years, frequency domain analyzes such as Discrete Cosine Transform and Discrete Wavelet Transform (DWT) have been widely used in the field of image compression due to their well localized property of its coefficients in both frequency and space domain. This work also deals with image compression based on frequency domain transformation. As the medical images are very important for diagnosis, they require lossless compression to store them. However, the coefficients of DWT are real numbers; lossless compression cannot be achieved. To overcome this limitation, a variant of DWT named Lifting Wavelet Transform (LWT) is utilized in the proposed system. The proposed codec is applied on the decomposed image. The codec has also been synthesized using FPGA and the results are compared with simulation results and verified.

Multi-frequency effect towards High Conductivity Overburden Responses using Horizontal Coplanar (HCP) coil configuration for Landslide Hazard Instrumentation

The instrumentation for the sensing of natural disaster phenomena as like as landslide instrumentation has acquired great importance for the instrumentation community. The novel instrumentation for landslide application has been made and calibrated using Horizontal Coplanar (HCP) coil orientation. The early instrumentation for landslide slopes was gradually equipped with standard and automatic instrumentation consisting of three the piezometric cells, two deep-seated steel wire extensometers, four in clinometric tubes, a rainfall gauge, a snow gauge and an air thermometer. This novel instrumentation works in electromagnetic methods similar with electromagnetic methods in geophysics. HCP coil orientation is a coplanar array where both coils are horizontal. In HCP, the depth of sounding is about 1.5 times of the coils separation which have maximum coupled configuration (HCP, VCP, and Vertical Coaxial configuration). The overburden response had inverted the percent value of maximum negative response then there were three maximum response amplitude peaks. Measurement and data processing were performed using a computer through Delphi program. The diagonal cross sections of the overburden as the centre were the maximum value of inverted response of anomaly positions. In aluminium thin plate overburden, the diagonal cross section point as the overburden centre was the maximum value of inverting value of the highest minimum response amplitude. The measurement graphic in the computer screen with several types of overburdens would be displayed. As the result, that the overburden widths for overburden were determined by subtracted of two turning points positions. The overburden positions were accurate for Type P overburden. The master curve had a high anomaly contrasts with two of positive anomaly peaks. Otherwise, the anomaly positions were between two of the negative anomaly peaks.

Multi-Stage Pedestrian Crossings and Two-Stage Bicycle Turns: Delay Estimation and Signal Timing Techniques for Limiting Pedestrian and Bicycle Delay

Signalized intersections sometimes involve multistage pedestrian crossings, in which pedestrians cross to one or more islands and then wait there for a signal to continue. When signals are timed without attention to pedestrian progression, pedestrian delay at multistage crossings can be very long. This paper addresses two issues. First, pedestrian delay at multistage crossings is rarely evaluated because there are no tools in the industry for that purpose except microsimulation. We present a numerical method for determining crossing delay with any number of stages and with the possibility of multiple WALK intervals per cycle. The same method can be applied to single stage crossings, to diagonal two-stage crossings where pedestrians may have path choice, and bicycle two-stage turns. This method has been implemented in a freely available online tool. Second, we describe several signal timing techniques for improving pedestrian and bicyclist progression, and thus reducing their delay, through multistage crossings. They include reservice for selected crossing phases, left turn overlaps, having pedestrian phases overlap each other, and bidirectional bicycle crossings which create path options for two-stage turns. Examples show the potential for large reductions in pedestrian delay, often with little or no increase in vehicular delay. In one example, the addition of a short pedestrian overlap phase reduced average pedestrian delay at a 3-stage crossing by 82 s while average vehicular delay increased by only 0.5 s.

EFFICIENCY OF DIFFERENT STRENGTHENING TECHNIQUES ON SEISMIC PERFORMANCE OF R.C. FRAMES

This paper presents a theoretical finite element study on effect of different strengthening techniques on structural behavior of the reinforced concrete frames subjected to earthquake motion. In the study, diagonal cross bracing, masonry infill wall, externally CFRP laminates, and reinforced concrete jacketing for columns are considered as different strengthening techniques of one story reinforced concrete bare frame. Time history analysis for the frame subjected to EL-Centro (1940 N-S) earthquake ground motion is carried out using ETABS software. The obtained results from the time history analysis including axial and shear stresses, lateral displacement, acceleration and base shear with time are illustrated and discussed with/ or without the strengthening techniques. The study illustrates the influence and enhancement of each technique on the performance of one story bare frame subjected to EL-Centro earthquake motion.

Lateral performance of timber shear walls reinforced by prestressed diagonal cross bars

Lateral performance of timber shear walls reinforced by prestressed diagonal cross bars

Octagon with Diagonal Cross Hair Search Algorithm for Efficient Medical Image Compression

Octagon with Diagonal Cross Hair Search Algorithm for Efficient Medical Image Compression

Optimization of structural patterns for tall buildings: The case of diagrid

Diagrid structures have recently emerged as a new solution for tall buildings which merges inherent structural efficiency, decorative qualities and morphological versatility. In this paper a design strategy based on sizing optimization techniques is proposed as either an alternative to, or a refinement of, the preliminary sizing methods suggested in literature for regular diagrids. In addition, the approach here provided can also be used for complex and non conventional patterns, as opposite to the existing procedures that mainly deal with regular geometries. Different geometrical patterns (regular, variable angle, variable density) for diagrid structures are explored, together with a fully non uniform diagrid-like pattern which mimics the principal stress trajectories on the building façade. Strategies for the generation, preliminary design and structural optimization are proposed for the different patterns; in particular the optimization process is treated with mono-objective genetic algorithms, by minimizing the structural weight and imposing a constraint condition on the lateral stiffness of the building. Thorough comparisons, both among the patterns, and between the outcomes of the preliminary design procedures and the optimization processes, are carried out, in terms of: unit structural weight, diagonal cross section distribution along elevation, deformed configuration, lateral displacements, interstory drift ratio, diagonal strength demand to capacity ratio.

Stability of a pretensioned latticed three-dimensional arch structure with cross cable-strut arrangement

An innovative pretensioned latticed three-dimensional (3D) arch structure with cross cable-strut arrangement is proposed based on the concept of beam string structure with consideration of the indoor headroom. Three cable-strut arrangement schemes of the cable latticed 3D arch are analyzed and the in-plane stabilities of the arches with different cable-strut schemes are compared. Also, the influence of cable anchorage position on the in-plane stability of the pretensioned latticed 3D arch is investigated. The configuration and stability of the parallel cable-arch integral structure with the optimal cable-strut arrangement are studied. The effect of both the transverse diagonal cross bracings and the amount of the longitudinal latticed 3D beams on the buckling mode and stability capacity of the integral structure is studied. Additionally, the relationship between the structural stability capacity and the amount of parallel cable arches is discussed. Two simplified models for stability analysis of the integral structure are presented, and the corresponding calculation accuracies are also discussed. All this work will provide theoretical guidance to the actual engineering application of this structure.

Performance Analysis of Circular Sieve Owner Center Steel Crosses

Structures are required to behave ductile under horizontal loads such as earthquake and wind loads. It is related that the structural members of the structure, such as columns, beams, and the junctions of these members have sufficient strength under horizontal loads. There are many applications for steel buildings to exhibit sufficient performance against horizontal loads. The main application of these applications is the use of the steel curtain system. The purpose in this study is to determine the structural performance of some of the types of central steel crossed curtains in steel buildings with regular and irregular geometry, according to the selected section. The geometry of the central steel crossed curtain types is determined as diagonal and reverse V. The section geometry to be used for the crosses of these curtain types is chosen as circular pipe. When the dimensions of the diagonal profiles are selected in the selected structures, the same cross-sectional area is provided so that the construction cost is limited. The end of our analysis, the limit value of the performance of steel structures with regular and irregular geometries was investigated for diagonal and inverse crossing. The diagonal central steel cross curtain system has been found to have more energy damping capacity than the reverse V center steel cross curtain system. The nonlinear static analysis method was used in the structural analysis and finite element model of the study.

Novel Method of Constructing Two-Dimensional Correlation Spectroscopy without Subtracting a Reference Spectrum.

In this study, we propose a new approach to generate two-dimension spectra to enhance the intensity of cross peaks relevant to intermolecular interaction. We investigate intermolecular interaction between two solutes (denoted as P and Q, where P has a characteristic peak at XP) dissolved in the same solvent via the near diagonal cross peaks around the coordinate (XP, XP) in a two-dimensional (2D) asynchronous spectrum of generalized spectroscopy. Because of physical constrains in many cases, the variation ranges of the initial concentrations of P or Q must be kept very narrow, leading to very weak cross peak intensities. The weak cross peaks vulnerable to noise bring about difficulty in the investigation of subtle intermolecular interaction. Herein, we propose a new of way constructing a 2D asynchronous spectrum without the subtraction of the average spectrum often used as a reference spectrum. Mathematical analysis and computer simulation demonstrate that the near diagonal cross peaks around the coordinate (XP, XP) in the 2D asynchronous spectrum using the new approach possess two characteristics: (1) they can still reflect an intermolecular interaction reliably; 2) the absolute intensities of the cross peaks are significantly stronger than those generated by the conventional method. We incorporate the novel method with the DAOSD (double asynchronous orthogonal sample design scheme) approach and applied the modified DAOSD approach to study hydrogen bonding behavior in diethyl either/methanol/THF system. The new approach made the weak cross peaks, which are not observable in 2D asynchronous spectrum generated using conventional approach, become observable. The appearance of the cross peak demonstrate that When a small amount of THF is introduced into diethyl solution containing low amount of methanol, THF breaks the methanol-diethyl ether complex and forms methanol-THF complex via new hydrogen bond. This process takes place in spite of the fact that the content of diethyl ether is overwhelmingly larger than that of THF. The above result demonstrates that the new approach described in this article is applicable to enhance intensity of cross peaks in real chemical systems.

Protective and Blast Resistive Design of Posttensioned Box Girders Using Computational Geometry

The optimal tendon profile and its associated duct geometry for posttensioned box girders are investigated. A computational algorithm has been developed to determine an ideal shape for the tendon and duct. The algorithm is based on a diagonal cross point in the Magnel quadrilateral and uses computational geometry instead of graphical drawing. Thereafter, an ideal parabolic and linear tendon profiles can be calculated from which the covering duct could be shaped. To check the optimality of the results, an automatic examination of Magnel diagrams in various cross sections is incorporated in the algorithm. This enables a unique prestress level to be selected that suits all sections. Then, the mideccentricity of the two crossing points with a common prestress line is chosen as a design eccentricity in each cross section. The optimal duct shape is determined based on such automatic inspections. In a numerical example, the linear, parabolic, and optimal duct geometries are compared and drawn. It is concluded that both linear and parabolic duct shapes can be very close to an optimal shape. In a numerical example, an optimal, box girder with linear open access‐type tendons is designed that can withstand extra blast load when explosion occurs.

Validation of an Agent-Based Microscopic Pedestrian Simulation Model at a Scramble Phase Signalized Intersection

Recently, an agent-based pedestrian simulation model was developed at the University of British Columbia to model detailed pedestrian interactions. The model was originally calibrated and validated with video data, collected at a signalized intersection in Vancouver. However, it is important to investigate the applicability of the model in different walking environments. The main objective of this study was to assess the model performance in handling pedestrian interactions at a scramble phase signalized intersection in Oakland, California. The intersection had four conventional crosswalks in addition to two diagonal crosswalks, used during the scramble pedestrian phase. Model parameters were calibrated with a genetic algorithm, which aimed to minimize the location and speed error between simulated and actual trajectories, extracted from the video sequence through computer vision. Validation results showed that the model was capable of reproducing pedestrian trajectories with high accuracy in regard to average location and speed error. The average location error for 271 pedestrians considered in the validation was 0.49 m, while the average speed error was 0.04 m/s. Detailed analysis of crossing speed for both conventional and diagonal crossings was presented, and the ability of the model to produce the same speed distributions observed in actual data was confirmed. Furthermore, the ability of the model to reproduce five interactions that were frequently observed in the data was assessed. Results showed that the model was capable of reproducing the actual behavior taken by pedestrians during these interactions with high accuracy, from 80% to 100%.

Diagonal and off-diagonal susceptibilities of conserved quantities in relativistic heavy-ion collisions

Susceptibilities of conserved quantities, such as baryon number, strangeness and electric charge are sensitive to the onset of quantum chromodynamics phase transition, and are expected to provide information on the matter produced in heavy-ion collision experiments. A comprehensive study of the second order diagonal susceptibilities and cross correlations has been made within a thermal model approach of the hadron resonance gas model as well as with a hadronic transport model, ultra-relativistic quantum molecular dynamics. We perform a detailed analysis of the effect of detector acceptances and choice of particle species in the experimental measurements of the susceptibilities for heavy-ion collisions corresponding to = 4 GeV to 200 GeV. The transverse momentum cutoff dependence of suitably normalised susceptibilities are proposed as useful observables to probe the properties of the medium at freezeout.

Two-Dimensional Infrared Study of Vibrational Coupling between Azide and Nitrile Reporters in a RNA Nucleoside.

The vibrations in the azide, N3, asymmetric stretching region and nitrile, CN, symmetric stretching region of 2'-azido-5-cyano-2'-deoxyuridine (N3CNdU) are examined by two-dimensional infrared (2D IR) spectroscopy. At earlier waiting times, the 2D IR spectrum shows the presence of both vibrational transitions along the diagonal and off-diagonal cross peaks indicating vibrational coupling. The coupling strength is determined from the off-diagonal anharmonicity to be 66 cm(-1) for the intramolecular distance of ∼7.9 Å, based on a structural map generated for this model system. In addition, the frequency-frequency correlation decay is detected, monitoring the solvent dynamics around each individual probe position. Overall, these vibrational reporters can be utilized in tandem to simultaneously track global structural information and fast structural fluctuations.

Design of a Transmitarray Using Split Diagonal Cross Elements With Limited Phase Range

A triple-layer transmitarray consisting of unit cells with limited phase range is studied in this letter. A 255° phase shift with high transmission (better than $-\hbox{1 dB}$ ) is achieved by the proposed split diagonal cross element. This limitation of phase range makes the commonly used ray-tracing method unable to solve the required phase shift distribution and maintain high transmission simultaneously. A global search method, namely the particle swarm optimization, is applied to address the constrained phase only synthesis problem. The results suggest that the backward radiation is suppressed by 9.2 dB and the sidelobe by 4.1 dB compared to the ray-tracing method. A prototype has been manufactured and tested. The measured performance shows a good agreement with the simulation by a gain level of 18.9 dBi and a 1-dB bandwidth of 9.6%.

Changes in the hydraulic properties of a clay soil under long-term irrigation with treated wastewater

Treated wastewater (TWW) is an important water resource, especially in semiarid and arid regions. However, there are concerns that irrigation with TWW could lead to degradation of soil physical and hydraulic properties. The objective of our study was to determine the effects of long-term (≥15years) irrigation with secondary TWW on some basic and hydraulic soil properties of a clay soil. Undisturbed soil samples (cores) were taken to a depth of 4.5m (in sections of 0.5m) over a diagonal cross section of a five year old orchard irrigated with TWW. Samples were taken from five sites within the tree rows (i.e., representing soil directly affected by TWW; referred to as “within rows”) and four sites between the rows of trees (i.e., the control treatment representing soil that was not directly subjected to the irrigation water; referred to as “between rows”). Soil analyses included an array of basic properties, determination of a continuous particle size distribution and measurement of the saturated hydraulic conductivity (HC). The latter two were used for the computation of soil characteristic curve, Θ(ψ), and the unsaturated HC curve, K(ψ). Similar bulk density, moisture content, cation exchange capacity, pH and exchangeable sodium percentage (ESP) levels were observed for the TWW irrigated samples and the control ones. However, irrigation with TWW caused a significant reduction in the saturated HC, Ks. The computed Θ(ψ) curve at a given soil depth, averaged over the different sites, was similar for the TWW-irrigated samples and the control ones. On the contrary, the computed K(ψ) curve at a given soil depth, averaged over the different sites, for the TWW-irrigated samples were lower than those for the control samples at matric potential ≳−100cm (=pF≲2); similar K(ψ) values were noted at pF>2 for the two treatments. The observed differences in the hydraulic properties between the TWW-irrigated samples and the control ones in this specific matric potential range, albeit the similarity in their ESP, suggest that long term irrigation with TWW affected structural porosity via narrowing macro- and mesopores (>70 and 30–70μm, respectively). It is further postulated that this adverse impact of irrigation with TWW on structural porosity might be associated with previously reported effects of TWW on the composition of the dissolved organic matter in the soil solution.

Solid solutions based on laminated chalcogenides of bismuth and lead in ternary reciprocal Pb, Bi||Se, Te system

X-ray diffraction and metallographic studies of solid solution alloys are carried out in the PbSe–Bi2Se3 and PbTe–Bi2Te3 quasi-binary systems. Also, the alloys in the PbTe–Bi2Se3 and PbSe–Bi2Te3 diagonal cross sections of the reciprocal ternary system Pb, Bi||Se, Te are studied in the range of compositions near the solid solution PbTe1-xSex (δ). The PbSe–Bi2Se3 phase diagram is refined and it is shown that the phases with orthorhombic lattices existing in the PbS–Bi2S3 system do not form in the PbSe–Bi2Se3 system. In the Pb, Bi||Se, Te ternary reciprocal system, the presence of extended ranges of quadruple solid solutions of trigonal symmetry based on seven compounds is detected: Pb2Bi2Te5, Pb3Bi4Te9, PbBi2Te4, Pb2Bi6Te11, PbBi4Te7, PbBi6Te10, and PbBi8Te13 from the homologous series [PbTe]m[Bi2Te3]n. The extent of the δ range of the solid solution with NaCl cubic structure is established at the PbTe–PbSe side. It is found that the extent of the δ-solid solution region decreases as the PbTe content increases. The phase diagram of the PbSe–PbTe–Bi2Te3–Bi2Se3 reciprocal system illustrates the phase composition of the alloys after homogenizing at 770 K.