Search results for: lateral slab
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 889

Search results for: lateral slab

319 Effects of the Mass and Damping Matrix Model in the Non-Linear Seismic Response of Steel Frames

Authors: Alfredo Reyes-Salazar, Mario D. Llanes-Tizoc, Eden Bojorquez, Federico Valenzuela-Beltran, Juan Bojorquez, Jose R. Gaxiola-Camacho, Achintya Haldar

Abstract:

Seismic analysis of steel buildings is usually based on the use of the concentrated mass (ML) matrix and the Rayleigh damping matrix (C). Similarly, the initial stiffness matrix (KO) and the first two modes associated with lateral vibrations are commonly used to develop matrix C. The evaluation of the accuracy of these practices for the particular case of steel buildings with moment-resisting steel frames constitutes the main objective of this research. For this, the non-linear seismic responses of three models of steel frames, representing low-, medium- and high-rise steel buildings, are considered. Results indicate that if the ML matrix is used, shears and bending moments in columns are underestimated by up to 30% and 65%, respectively when compared to the corresponding results obtained with the consistent mass matrix (MC). It is also shown that if KO is used in C instead of the tangent stiffness matrix (Kt), axial loads in columns are underestimated by up to 80%. It is concluded that the consistent mass matrix should be used in the structural modelling of moment-resisting steel frames and that the tangent stiffness matrix should be used to develop the Rayleigh damping matrix.

Keywords: moment-resisting steel frames, consistent and concentrated mass matrices, non-linear seismic response, Rayleigh damping

Procedia PDF Downloads 139
318 Effect of Cantilever Sheet Pile Wall to Adjacent Buildings

Authors: Ahmed A. Mohamed Aly

Abstract:

Ground movements induced from excavations is a major cause of deformation and damage to the adjacent buildings and utilities. With the increasing rate of construction work in urban area, this problem is growing more significant and has become the cause of numerous legal disputes. This problem is investigated numerically in the present study using finite element method. Five-story reinforced concrete building rests on raft foundation is idealized as two dimensional model. The building is considered to be constructed adjacent to excavation affected by an adjacent excavation in medium sand. Excavation is supported using sheet pile wall. Two dimensional plane strain program PLAXIS is used in this study. 15 nodes triangular element is used to idealize soil with Mohr-Coulomb model. Five nodes isoperimetric beam element is used to idealize sheet pile and building. Interface element is used to represent the contact between beam element and soil. Two parameters were studied, the first is the foundation depth and the second is the building distance from the excavation. Nodal displacements and elements straining actions were obtained and studied from the analyzed finite element model results.

Keywords: excavation, relative distance, effective stresses, lateral deformation, relative depth

Procedia PDF Downloads 129
317 Laboratory Model Tests on Encased Group Columns

Authors: Kausar Ali

Abstract:

There are several ground treatment techniques which may meet the twin objectives of increasing the bearing capacity with simultaneous reduction of settlements, but the use of stone columns is one of the most suited techniques for flexible structures such as embankments, oil storage tanks etc. that can tolerate some settlement and used worldwide. However, when the stone columns in very soft soils are loaded; stone columns undergo excessive settlement due to low lateral confinement provided by the soft soil, leading to the failure of the structure. The poor performance of stone columns under these conditions can be improved by encasing the columns with a suitable geosynthetic. In this study, the effect of reinforcement on bearing capacity of composite soil has been investigated by conducting laboratory model tests on floating and end bearing long stone columns with l/d ratio of 12. The columns were reinforced by providing geosynthetic encasement over varying column length (upper 25%, 50%, 75%, and 100% column length). In this study, a group of columns has been used instead of single column, because in the field, columns used for the purpose always remain in groups. The tests indicate that the encasement over the full column length gives higher failure stress as compared to the encasement over the partial column length for both floating and end bearing long columns. The performance of end-bearing columns was found much better than the floating columns.

Keywords: geosynthetic, ground improvement, soft clay, stone column

Procedia PDF Downloads 415
316 Evaluation of Condyle Alterations after Orthognathic Surgery with a Digital Image Processing Technique

Authors: Livia Eisler, Cristiane C. B. Alves, Cristina L. F. Ortolani, Kurt Faltin Jr.

Abstract:

Purpose: This paper proposes a technically simple diagnosis method among orthodontists and maxillofacial surgeons in order to evaluate discrete bone alterations. The methodology consists of a protocol to optimize the diagnosis and minimize the possibility for orthodontic and ortho-surgical retreatment. Materials and Methods: A protocol of image processing and analysis, through ImageJ software and its plugins, was applied to 20 pairs of lateral cephalometric images obtained from cone beam computerized tomographies, before and 1 year after undergoing orthognathic surgery. The optical density of the images was analyzed in the condylar region to determine possible bone alteration after surgical correction. Results: Image density was shown to be altered in all image pairs, especially regarding the condyle contours. According to measures, condyle had a gender-related density reduction for p=0.05 and condylar contours had their alterations registered in mm. Conclusion: A simple, viable and cost-effective technique can be applied to achieve the more detailed image-based diagnosis, not depending on the human eye and therefore, offering more reliable, quantitative results.

Keywords: bone resorption, computer-assisted image processing, orthodontics, orthognathic surgery

Procedia PDF Downloads 140
315 Electronic Stability Control for a 7 DOF Vehicle Model Using Flex Ray and Neuro Fuzzy Techniques

Authors: Praveen Battula

Abstract:

Any high performance car has the tendency to over steer and Understeer under slippery conditions, An Electronic Stability Control System is needed under these conditions to regulate the steering of the car. It uses Anti-Lock Braking System (ABS) and Traction Control and Wheel Speed Sensor, Steering Angle Sensor, Rotational Speed Sensors to correct the problems. The focus of this paper is to improve the driving dynamics and safety by controlling the forces applied on each wheel. ESC Control the Yaw Stability, traction controls the Roll Stability, where actually the vehicle slip rate and lateral acceleration is controlled. ESC uses differential braking on all four brakes independently to control the vehicle’s motion. A mathematical model is developed in Simulink for the FlexRay based Electronic Stability Control. Vehicle steering is developed using Neuro Fuzzy Logic Controller. 7 Degrees of Freedom Vehicle Model is used as a Plant Model using dSpace autobox. The Performance of the system is assessed using two different road Scenarios, Vehicle Control under standard maneuvering conditions. The entire system is set using Dspace Control Desk. Results are provided by comparison of how a Vehicle with and without Electronic Stability Control which shows an improved performance in control.

Keywords: ESC, flexray, chassis control, steering, neuro fuzzy, vehicle dynamics

Procedia PDF Downloads 436
314 “The Forgotten People:” Analyzing the Invisible, Intersectional Discrimination Against Metis Women

Authors: Yifan Jia

Abstract:

The Metis is a group of indigenous peoples in Canada. Having experienced centuries of injustices, beginning with colonialism dating back to the 16th century, culminating with military defeats in the 1800s and the establishment of residential schools, and continuing with structural injustices in the 21st century, Metis people have long been, and continue to be marginalized and made invisible in the Canadian society. In particular, Metis women born between 1997 and 2012 face intersectional discrimination based on not only race, but also a multitude of identity factors, including gender, age, geographical location, health, sexual orientation, and lateral violence from First Nations peoples. This paper uncovers the multilayered oppression against young Metis women through a literature review and uses several theories to analyze the invisibility of this discrimination in society, including color-blind racism, collective shame, lack of understanding of intersectionality, and Mauvaise foi (bad faith). To address the invisible, intersectional discrimination against young Metis women, several suggestions and possibilities could be considered. These include amending the education system, fostering group affiliation, bringing structural changes to federal policies and funding systems, and cooperating with other indigenous nations such as First Nations and Inuit.

Keywords: discrimination, Metis Women, indigenous rights, intersectionality

Procedia PDF Downloads 55
313 Design of Reduced Links for Link-to-Column Connections in Eccentrically Braced Frames

Authors: Daniel Y. Abebe, Jaehyouk Choi

Abstract:

Link-to-column connection in eccentrically braced frames (EBF) has been a critical problem since the link flange connected to the column fractured prior to the required link rotation. Even though the problem in link-to-column connection still exist, the use of an eccentrically braced frame (EBF) is increasing day by day as EBF have high elastic stiffness, stable inelastic response under repeated lateral loading, and excellent ductility and energy dissipation capacity. In order to address this problem, a reduced web and flange link section is proposed and evaluated in this study. Reducing the web with holes makes the link to control the failure at the edge of holes introduced. Reducing the flange allows the link to control the location at which the plastic hinge is formed. Thus, the failure supposed to occur in the link flange connected at the connection move to the web and to the reduced link flange. Nonlinear FE analysis and experimental investigations have been done on the developed links, and the result shows that the link satisfies the plastic rotation limit recommended in AICS-360-10. Design equations that define the behavior of the proposed link have been recommended, and the equations were verified through the experimental and FE analysis results.

Keywords: EBFs, earthquake disaster, link-to-column connection, reduced link section

Procedia PDF Downloads 365
312 On the Homology Modeling, Structural Function Relationship and Binding Site Prediction of Human Alsin Protein

Authors: Y. Ruchi, A. Prerna, S. Deepshikha

Abstract:

Amyotrophic lateral sclerosis (ALS), also known as “Lou Gehrig’s disease”. It is a neurodegenerative disease associated with degeneration of motor neurons in the cerebral cortex, brain stem, and spinal cord characterized by distal muscle weakness, atrophy, normal sensation, pyramidal signs and progressive muscular paralysis reflecting. ALS2 is a juvenile autosomal recessive disorder, slowly progressive, that maps to chromosome 2q33 and is associated with mutations in the alsin gene, a putative GTPase regulator. In this paper we have done homology modeling of alsin2 protein using multiple templates (3KCI_A, 4LIM_A, 402W_A, 4D9S_A, and 4DNV_A) designed using the Prime program in Schrödinger software. Further modeled structure is used to identify effective binding sites on the basis of structural and physical properties using sitemap program in Schrödinger software, structural and function analysis is done by using Prosite and ExPASy server that gives insight into conserved domains and motifs that can be used for protein classification. This paper summarizes the structural, functional and binding site property of alsin2 protein. These binding sites can be potential drug target sites and can be used for docking studies.

Keywords: ALS, binding site, homology modeling, neuronal degeneration

Procedia PDF Downloads 378
311 Experimental Studies of Spiral-Confined HSCFST Columns under Uni-Axial Compression

Authors: Mianheng Lai, Johnny Ching Ming Ho, Hoat Joen Pam

Abstract:

Concrete-filled-steel-tube (CFST) columns are becoming increasingly popular owing to the superior behavior contributed by the composite action. However, this composite action cannot be fully developed because of different dilation properties between steel tube and concrete. During initial compression, there will be de-bonding between the constitutive materials. As a result, the strength, initial stiffness and ductility of CFST columns reduce significantly. To resolve this problem, external confinement in the form of spirals is proposed to improve the interface bonding. In this paper, a total of 14CFST columns with high-strength as well as ultra-high-strength concrete in-filled were fabricated and tested under uni-axial compression. From the experimental results, it can be concluded that the proposed spirals can improve the strength, initial stiffness, ductility and the interface bonding condition of CFST columns by restraining the lateral expansion of steel tube and core concrete. Moreover, the failure modes of confined core concrete change due to the strong confinement provided by spirals.

Keywords: concrete-filled-steel-tube, confinement, failure mode, high-strength concrete, spirals

Procedia PDF Downloads 340
310 Analysis Of Fine Motor Skills in Chronic Neurodegenerative Models of Huntington’s Disease and Amyotrophic Lateral Sclerosis

Authors: T. Heikkinen, J. Oksman, T. Bragge, A. Nurmi, O. Kontkanen, T. Ahtoniemi

Abstract:

Motor impairment is an inherent phenotypic feature of several chronic neurodegenerative diseases, and pharmacological therapies aimed to counterbalance the motor disability have a great market potential. Animal models of chronic neurodegenerative diseases display a number deteriorating motor phenotype during the disease progression. There is a wide array of behavioral tools to evaluate motor functions in rodents. However, currently existing methods to study motor functions in rodents are often limited to evaluate gross motor functions only at advanced stages of the disease phenotype. The most commonly applied traditional motor assays used in CNS rodent models, lack the sensitivity to capture fine motor impairments or improvements. Fine motor skill characterization in rodents provides a more sensitive tool to capture more subtle motor dysfunctions and therapeutic effects. Importantly, similar approach, kinematic movement analysis, is also used in clinic, and applied both in diagnosis and determination of therapeutic response to pharmacological interventions. The aim of this study was to apply kinematic gait analysis, a novel and automated high precision movement analysis system, to characterize phenotypic deficits in three different chronic neurodegenerative animal models, a transgenic mouse model (SOD1 G93A) for amyotrophic lateral sclerosis (ALS), and R6/2 and Q175KI mouse models for Huntington’s disease (HD). The readouts from walking behavior included gait properties with kinematic data, and body movement trajectories including analysis of various points of interest such as movement and position of landmarks in the torso, tail and joints. Mice (transgenic and wild-type) from each model were analyzed for the fine motor kinematic properties at young ages, prior to the age when gross motor deficits are clearly pronounced. Fine motor kinematic Evaluation was continued in the same animals until clear motor dysfunction with conventional motor assays was evident. Time course analysis revealed clear fine motor skill impairments in each transgenic model earlier than what is seen with conventional gross motor tests. Motor changes were quantitatively analyzed for up to ~80 parameters, and the largest data sets of HD models were further processed with principal component analysis (PCA) to transform the pool of individual parameters into a smaller and focused set of mutually uncorrelated gait parameters showing strong genotype difference. Kinematic fine motor analysis of transgenic animal models described in this presentation show that this method isa sensitive, objective and fully automated tool that allows earlier and more sensitive detection of progressive neuromuscular and CNS disease phenotypes. As a result of the analysis a comprehensive set of fine motor parameters for each model is created, and these parameters provide better understanding of the disease progression and enhanced sensitivity of this assay for therapeutic testing compared to classical motor behavior tests. In SOD1 G93A, R6/2, and Q175KI mice, the alterations in gait were evident already several weeks earlier than with traditional gross motor assays. Kinematic testing can be applied to a wider set of motor readouts beyond gait in order to study whole body movement patterns such as with relation to joints and various body parts longitudinally, providing a sophisticated and translatable method for disseminating motor components in rodent disease models and evaluating therapeutic interventions.

Keywords: Gait analysis, kinematic, motor impairment, inherent feature

Procedia PDF Downloads 344
309 On the Stability Exact Analysis of Tall Buildings with Outrigger System

Authors: Mahrooz Abed, Amir R. Masoodi

Abstract:

Many structural lateral systems are used in tall buildings such as rigid frames, braced frames, shear walls, tubular structures and core structures. Some efficient structures for drift control and base moment reduction in tall buildings is outrigger and belt truss systems. When adopting outrigger beams in building design, their location should be in an optimum position for an economical design. A range of different strategies has been employed to identify the optimum locations of these outrigger beams under wind load. However, there is an absence of scientific research or case studies dealing with optimum outrigger location using buckling analysis. In this paper, one outrigger system is considered at the middle of height of structure. The optimum location of outrigger will be found based on the buckling load limitation. The core of structure is modeled by a clamped tapered beam. The exact stiffness matrix of tapered beam is formulated based on the Euler-Bernoulli theory. Finally, based on the buckling load of structure, the optimal location of outrigger will be found.

Keywords: tall buildings, outrigger system, buckling load, second-order effects, Euler-Bernoulli beam theory

Procedia PDF Downloads 384
308 Pyelography by Intraosseous Injection of Iodixanol in Persian Squirrel

Authors: Mehdi Tavana, Seyedeh Zeinab Peighambarzadeh

Abstract:

Pyelography is used for morphologic and especially functional studies of the urinary tracts. There are many indications for excretory Pyelography in humans and animals. Intravenous Pyelography is the most practical method; other Pyelography techniques were manipulated because of difficulties for finding veins in small size of the patients. At the best of times, the combination of small veins and abundant subcutaneous tissue makes vascular access difficult or impossible, therefore, another methods of administration of contrast media is desired. This study was performed to evaluate the feasibility of intraosseous injection of iodixanol in providing a safe and diagnostic urogram in Persian squirrel. Fourteen hundred mg iodine per kilogram body weight of iodixanol was injected subcutaneously over tibial tuberosity on ten clinically healthy adult Persian squirrels with no signs of urinary system disorder. Lateral and ventrodorsal radiographs were taken every 2 minutes until the pyelogram was finished. Intraosseous injection of iodixanol was successful to show nephrogram, pyelogram, uretrogram and cystogram clearly. There were no abnormal clinical signs after one week of experiments. Biochemical and hematological profiles were in normal ranges. It is concluded that intraosseous Pyelography is an effective and reliable method for Pyelography studies in squirrel. Microscopic examinations of the kidneys and the site of injection after one week were normal.

Keywords: pyelography, intraosseous injection, iodixanol, persian squirrel

Procedia PDF Downloads 515
307 Numerical Investigation of the Effect of Sidewalls on Low-Speed Finite Width Cavity Flows

Authors: Foo Kok, Varun Thangamani

Abstract:

Rectangular cavities with a full-span or finite-width configuration have been the basis of much previous research on cavity flows. However, much less attention has been given to the influence of sidewalls, in particular, on low-speed cavity flows. In this study, the flow characteristics of two separate low-speed finite-width cavities with a Reynolds number of 𝑅𝑒𝐷 = 10⁴ are examined using large eddy simulations. Two different lateral boundary conditions are used to investigate the influence of sidewalls on the self-sustaining oscillations and the three-dimensional flow fields inside the cavities. The results show that the full-span finite width cavities are less sensitive to the sidewall effect at a low length-to-width ratio 𝐿/𝐷. The increase in 𝐿/𝐷 leads to a departure from two-dimensional instability and results in the loss of spanwise homogeneity. The analysis of the spanwise flow structures shows that these effects correspond closely to the declination of the centrifugal force from the primary recirculation zone. Such effects are also reflected in the distinct modulation of the secondary vortices in the primary recirculation zone, which suggests that the instabilities observed in the full-span finite-width cavity flows are predominantly dependent on the secondary motion from the primary recirculation zone.

Keywords: LES, cavity flows, unsteady shear layer, instability modes, secondary flow

Procedia PDF Downloads 49
306 Comparison Study between Deep Mixed Columns and Encased Sand Column for Soft Clay Soil in Egypt

Authors: Walid El Kamash

Abstract:

Sand columns (or granular piles) can be employed as soil strengthening for flexible constructions such as road embankments, oil storage tanks in addition to multistory structures. The challenge of embedding the sand columns in soft soil is that the surrounding soft soil cannot avail the enough confinement stress in order to keep the form of the sand column. Therefore, the sand columns which were installed in such soil will lose their ability to perform needed load-bearing capacity. The encasement, besides increasing the strength and stiffness of the sand column, prevents the lateral squeezing of sands when the column is installed even in extremely soft soils, thus enabling quicker and more economical installation. This paper investigates the improvement in load capacity of the sand column by encasement through a comprehensive parametric study using the 3-D finite difference analysis for the soft clay of soil in Egypt. Moreover, the study was extended to include a comparison study between encased sand column and Deep Mixed columns (DM). The study showed that confining the sand by geosynthetic resulted in an increment of shear strength. That result paid the attention to use encased sand stone rather than deep mixed columns due to relative high permeability of the first material.

Keywords: encased sand column, Deep mixed column, numerical analysis, improving soft soil

Procedia PDF Downloads 367
305 Study on Buckling and Yielding Behaviors of Low Yield Point Steel Plates

Authors: David Boyajian, Tadeh Zirakian

Abstract:

Stability and performance of steel plates are characterized by geometrical buckling and material yielding. In this paper, the geometrical buckling and material yielding behaviors of low yield point (LYP) steel plates are studied from the point of view of their application in steel plate shear wall (SPSW) systems. Use of LYP steel facilitates the design and application of web plates with improved buckling and energy absorption capacities in SPSW systems. LYP steel infill plates may yield first and then undergo inelastic buckling. Hence, accurate determination of the limiting plate thickness corresponding to simultaneous buckling and yielding can be effective in seismic design of such lateral force-resisting and energy dissipating systems. The limiting thicknesses of plates with different loading and support conditions are determined theoretically and verified through detailed numerical simulations. Effects of use of LYP steel and plate aspect ratio parameter on the limiting plate thickness are investigated as well. In addition, detailed studies are performed on determination of the limiting web-plate thickness in code-designed SPSWs. Some practical recommendations are accordingly provided for efficient seismic design of SPSW systems with LYP steel infill plates.

Keywords: buckling, low yield point steel, plates, steel plate shear walls, yielding

Procedia PDF Downloads 392
304 Microstructure of Ti – AlN Composite Produced by Selective Laser Melting

Authors: Jaroslaw Mizera, Pawel Wisniewski, Ryszard Sitek

Abstract:

Selective Laser Melting (SLM) is an advanced additive manufacturing technique used for producing parts made of wide range of materials such as: austenitic steel, titanium, nickel etc. In the our experiment we produced a Ti-AlN composite from a mixture of titanium and aluminum nitride respectively 70% at. and 30% at. using SLM technique. In order to define the size of powder particles, laser diffraction tests were performed on HORIBA LA-950 device. The microstructure and chemical composition of the composite was examined by Scanning Electron Microscopy (SEM). The chemical composition in micro areas of the obtained samples was determined by of EDS. The phase composition was analyzed by X-ray phase analysis (XRD). Microhardness Vickers tests were performed using Zwick/Roell microhardness machine under the load of 0.2kG (HV0.2). Hardness measurements were made along the building (xy) and along the plane of the lateral side of the cuboid (xz). The powder used for manufacturing of the samples had a mean particle size of 41μm. It was homogenous with a spherical shape. The specimens were built chiefly from Ti, TiN and AlN. The dendritic microstructure was porous and fine-grained. Some of the aluminum nitride remained unmelted but no porosity was observed in the interface. The formed material was characterized by high hardness exceeding 700 HV0.2 over the entire cross-section.

Keywords: Selective Laser Melting, Composite, SEM, microhardness

Procedia PDF Downloads 127
303 Earthquake Retrofitting of Concrete Structures Using Steel Bracing with the Results of Linear and Nonlinear Static Analysis

Authors: Ehsan Sadie

Abstract:

The use of steel braces in concrete structures has been considered by researchers in recent decades due to its easy implementation, economics and the ability to create skylights in braced openings compared to shear wall openings as well as strengthening weak concrete structures to earthquakes. The purpose of this article is to improve and strengthen concrete structures with steel bracing. In addition, cases such as different numbers of steel braces in different openings of concrete structures and interaction between concrete frames and metal braces have been studied. In this paper, by performing static nonlinear analysis and examining ductility, the relative displacement of floors, examining the performance of samples, and determining the coefficient of behavior of composite frames (concrete frames with metal bracing), the behavior of reinforced concrete frames is compared with frame without bracing. The results of analyzes and studies show that the addition of metal bracing increases the strength and stiffness of the frame and reduces the ductility and lateral displacement of the structure. In general, the behavior of the structure against earthquakes will be improved.

Keywords: behavior coefficient, bracing, concrete structure, convergent bracing, earthquake, linear static analysis, nonlinear analysis, pushover curve

Procedia PDF Downloads 167
302 Cantilever Shoring Piles with Prestressing Strands: An Experimental Approach

Authors: Hani Mekdash, Lina Jaber, Yehia Temsah

Abstract:

Underground space is becoming a necessity nowadays, especially in highly congested urban areas. Retaining underground excavations using shoring systems is essential in order to protect adjoining structures from potential damage or collapse. Reinforced Concrete Piles (RCP) supported by multiple rows of tie-back anchors are commonly used type of shoring systems in deep excavations. However, executing anchors can sometimes be challenging because they might illegally trespass neighboring properties or get obstructed by infrastructure and other underground facilities. A technique is proposed in this paper, and it involves the addition of eccentric high-strength steel strands to the RCP section through ducts without providing the pile with lateral supports. The strands are then vertically stressed externally on the pile cap using a hydraulic jack, creating a compressive strengthening force in the concrete section. An experimental study about the behavior of the shoring wall by pre-stressed piles is presented during the execution of an open excavation in an urban area (Beirut city) followed by numerical analysis using finite element software. Based on the experimental results, this technique is proven to be cost-effective and provides flexible and sustainable construction of shoring works.

Keywords: deep excavation, prestressing, pre-stressed piles, shoring system

Procedia PDF Downloads 109
301 A Numerical Study on the Seismic Performance of Built-Up Battened Columns

Authors: Sophia C. Alih, Mohammadreza Vafaei, Farnoud Rahimi Mansour, Nur Hajarul Falahi Abdul Halim

Abstract:

Built-up columns have been widely employed by practice engineers in the design and construction of buildings and bridges. However, failures have been observed in this type of columns in previous seismic events. This study analyses the performance of built-up columns with different configurations of battens when it is subjected to seismic loads. Four columns with different size of battens were simulated and subjected to three different intensities of axial load along with a lateral cyclic load. Results indicate that the size of battens influences significantly the seismic behavior of columns. Lower shear capacity of battens results in higher ultimate strength and ductility for built-up columns. It is observed that intensity of axial load has a significant effect on the ultimate strength of columns, but it is less influential on the yield strength. For a given drift value, the stress level in the centroid of smaller size battens is significantly more than that of larger size battens signifying damage concentration in battens rather than chords. It is concluded that design of battens for shear demand lower than code specified values only slightly reduces initial stiffness of columns; however, it improves seismic performance of battened columns.

Keywords: battened column, built-up column, cyclic behavior, seismic design, steel column

Procedia PDF Downloads 243
300 Shunt Placement in Treatment of Hydrocephalus in Patients with Myelomeningocele

Authors: M. M. Akhmediev, J. R. Ashrapov, T. M. Akhmediev

Abstract:

Hydrocephalus frequently occurs with spina bifida, and up to 80% of such patients need to be shunted. Objective: It’s sought to improve the results of the surgical treatment of hydrocephalus in children with spina bifida. Methods: We have analyzed the results of the surgical treatment of 80 patients aged between 1 month and 1,5-year-old with hydrocephalus and myelomeningocele. All patients underwent surgery in the period of 2013-2018. Results: In all patients, spina bifida was associated with hydrocephalus with a predominant extension of the posterior horns of the lateral ventricles in the form of colpocephaly, Chiari malformation type 2. Based on the method “Choose right shunt” the determination of the point of critical deformation of the ventricular system was established, 47 (58.8%) patients for the 1st stage underwent ventriculoperitoneal (VP) shunt surgery with a low-pressure valve, 28 (35.0%) patients with medium pressure and 5 (6.2%) with high-pressure valve. Under or over drainage complications were not observed in the postoperative period. The 2nd stage of surgery for myelomeningocele repair was planned in 1-2 months with the follow-up head ultrasonography and electromyography study. Conclusion: The implantable shunt systems parameters chosen before surgery in the surgical management of hydrocephalus in children with myelomeningocele are important in the causes of under or over drainage states, cerebrospinal fluid leakage from the myelomeningocele sac. Management of hydrocephalus should be performed by considering myelomeningocele affecting craniospinal compliance.

Keywords: hydrocephalus, spina bifida, myelomeningocele, ventriculoperitoneal (VP) shunt

Procedia PDF Downloads 100
299 Comparison of Dynamic Balance Ability and Flexibility in Different Sports

Authors: Inci Kesilmis, Manolya Akin, Mehmet Melih Kesilmis

Abstract:

The aim of this research was to compare dynamic balance ability (bipedal, right, left foot) and plantar-dorsi flexion range of motion in fencers and swimmers. 43 fencers participated as volunteer with mean age 15.74±1.90year and mean training year 4.97±2.37year. 25 swimmers participated as volunteer with mean age 15.36±1.65 yr. and mean training year 5.98±2.35 yr. Dynamic balance measured while participants were standing in the anatomical position with prokin tecno body for bipedal, right, left foot. Plantar and dorsal flexion range of motion measured while participants in seated position on the examination table and goniometer placed on the lateral malleolus. For statistical analyses; independent samples t test was used. There were significant differences between bipedal (p < 0.05), right foot (p < 0.05), left foot (p < 0.05) dynamic balance ability in favor of fencers. Also there was significant difference between right and left foot dorsal flexion range of motion (p < 0.001) in favor of fencers. There was no significant difference in plantar flexion range of motion between fencers and swimmers. The difference observed in fencers may be due to the use of more dorsal flexion in action moves and that swimming does not impact loading sport and it is performed in pool.

Keywords: fencing, swimming, dynamic balance, flexibility

Procedia PDF Downloads 363
298 Analytical Formulae for the Approach Velocity Head Coefficient

Authors: Abdulrahman Abdulrahman

Abstract:

Critical depth meters, such as abroad crested weir, Venture Flume and combined control flume are standard devices for measuring flow in open channels. The discharge relation for these devices cannot be solved directly, but it needs iteration process to account for the approach velocity head. In this paper, analytical solution was developed to calculate the discharge in a combined critical depth-meter namely, a hump combined with lateral contraction in rectangular channel with subcritical approach flow including energy losses. Also analytical formulae were derived for approach velocity head coefficient for different types of critical depth meters. The solution was derived by solving a standard cubic equation considering energy loss on the base of trigonometric identity. The advantage of this technique is to avoid iteration process adopted in measuring flow by these devices. Numerical examples are chosen for demonstration of the proposed solution.

Keywords: broad crested weir, combined control meter, control structures, critical flow, discharge measurement, flow control, hydraulic engineering, hydraulic structures, open channel flow

Procedia PDF Downloads 259
297 Intraosseous Urography by Iodixanol in Persian Squirrels

Authors: Mehdi Tavana, Seyedeh Zeinab Peighambarzadeh

Abstract:

Excretory urography is used for morphologic and especially functional studies of the urinary tracts. There are many indications for excretory urography in humans and animals. Intravenous urography is the most practical method, other urography techniques were manipulated because of difficulties for finding veins in small size of the patients. At the best of times, the combination of small veins and abundant subcutaneous tissue make vascular access difficult or impossible, therefore, another methods of administration of contrast media is desired. This study was performed to evaluate the feasibility of intraosseous injection of iodixanol in providing a safe and diagnostic urogram in Persian squirrel. Fourteen hundreds mg iodine per kilogram body weight of iodixanol were injected subcutaneously over tibial tuberosity on ten clinically healthy adult Persian squirrels with no signs of urinary system disorder. Lateral and ventrodorsal radiographs were taken every 2 minutes until the pyelogram was finished. Intraosseous injection of iodixanol was successful to show nephrogram, pyelogram, uretrogram and cystogram clearly. There were no abnormal clinical signs after one week of experiments. Biochemical and hematological profiles were in normal ranges. It is concluded that intraosseous urography is an effective and reliable method for urography studies in squirrel. Microscopic examinations of the kidneys and the site of injection after one week were normal.

Keywords: intraosseous urography, iodixanol, Persian squirrel, morphologic

Procedia PDF Downloads 388
296 An Approximate Formula for Calculating the Fundamental Mode Period of Vibration of Practical Building

Authors: Abdul Hakim Chikho

Abstract:

Most international codes allow the use of an equivalent lateral load method for designing practical buildings to withstand earthquake actions. This method requires calculating an approximation to the fundamental mode period of vibrations of these buildings. Several empirical equations have been suggested to calculate approximations to the fundamental periods of different types of structures. Most of these equations are knowing to provide an only crude approximation to the required fundamental periods and repeating the calculation utilizing a more accurate formula is usually required. In this paper, a new formula to calculate a satisfactory approximation of the fundamental period of a practical building is proposed. This formula takes into account the mass and the stiffness of the building therefore, it is more logical than the conventional empirical equations. In order to verify the accuracy of the proposed formula, several examples have been solved. In these examples, calculating the fundamental mode periods of several farmed buildings utilizing the proposed formula and the conventional empirical equations has been accomplished. Comparing the obtained results with those obtained from a dynamic computer has shown that the proposed formula provides a more accurate estimation of the fundamental periods of practical buildings. Since the proposed method is still simple to use and requires only a minimum computing effort, it is believed to be ideally suited for design purposes.

Keywords: earthquake, fundamental mode period, design, building

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295 Seismic Behavior of Pile-Supported Bridges Considering Soil-Structure Interaction and Structural Non-Linearity

Authors: Muhammad Tariq A. Chaudhary

Abstract:

Soil-structure interaction (SSI) in bridges under seismic excitation is a complex phenomenon which involves coupling between the non-linear behavior of bridge pier columns and SSI in the soil-foundation part. It is a common practice in the study of SSI to model the bridge piers as linear elastic while treating the soil and foundation with a non-linear or an equivalent linear modeling approach. Consequently, the contribution of soil and foundation to the SSI phenomenon is disproportionately highlighted. The present study considered non-linear behavior of bridge piers in FEM model of a 4-span, pile-supported bridge that was designed for five different soil conditions in a moderate seismic zone. The FEM model of the bridge system was subjected to a suite of 21 actual ground motions representative of three levels of earthquake hazard (i.e. Design Basis Earthquake, Functional Evaluation Earthquake and Maximum Considered Earthquake). Results of the FEM analysis were used to delineate the influence of pier column non-linearity and SSI on critical design parameters of the bridge system. It was found that pier column non-linearity influenced the bridge lateral displacement and base shear more than SSI for majority of the analysis cases for the class of bridge investigated in the study.

Keywords: bridge, FEM model, reinforced concrete pier, pile foundation, seismic loading, soil-structure interaction

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294 Delineation of Oil – Polluted Sites in Ibeno LGA, Nigeria, Using Geophysical Techniques

Authors: Ime R. Udotong, Justina I. R. Udotong, Ofonime U. M. John

Abstract:

Ibeno, Nigeria hosts the operational base of Mobil Producing Nigeria Unlimited (MPNU), a subsidiary of ExxonMobil and the current highest oil and condensate producer in Nigeria. Besides MPNU, other oil companies operate onshore, on the continental shelf and deep offshore of the Atlantic Ocean in Ibeno, Nigeria. This study was designed to delineate oil polluted sites in Ibeno, Nigeria using geophysical methods of electrical resistivity (ER) and ground penetrating radar (GPR). Results obtained revealed that there have been hydrocarbon contaminations of this environment by past crude oil spills as observed from high resistivity values and GPR profiles which clearly show the distribution, thickness and lateral extent of hydrocarbon contamination as represented on the radargram reflector tones. Contaminations were of varying degrees, ranging from slight to high, indicating levels of substantial attenuation of crude oil contamination over time. Moreover, the display of relatively lower resistivities of locations outside the impacted areas compared to resistivity values within the impacted areas and the 3-D Cartesian images of oil contaminant plume depicted by red, light brown and magenta for high, low and very low oil impacted areas, respectively confirmed significant recent pollution of the study area with crude oil.

Keywords: electrical resistivity, geophysical investigations, ground penetrating radar, oil-polluted sites

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293 Camel Mortalities Due to Accidental Intoxcation with Ionophore

Authors: M. A. Abdelfattah, F. K. Waleed

Abstract:

Anticoccidials were utilized widely in veterinary practice for the avoidance of coccidiosis in poultry and assume a huge job as development promotants in ruminants. Ionophore harming is every now and again happens because of accidental access to medicated feed, errors in feed mixing, incorrect dosage calculation or misuse in non-recommended species. Camels on several farms in Eastern area of Saudi Arabia were accidently fed with a feed pellet containing 13 ppm salinomycin. One hundred and sixty-three camels died with mortality rate of 100%. The poisoning was clinically characterized by restlessness with tail lift to the top, jerk in the muscles of legs and thighs, excessive sweating, frequent setting and standing with body imbalance, lateral and sternal recumbences with the legs stretched back, eye tears with dilated pupil, vomiting of the stomach content, loss of consciousness and death of some of them. Feed analysis indicated the presence of salinomycin in pelleted feed in a range of 13 mg/kg-47 mg/kg. Necropsy findings and histopathological examinations were presented. Regulations and legal implications concerning with sale of contaminated feed in Saudi market are discussed in the light of feed law and by-law. The necessity for an effective implication of regulation concerning application of quality assurance systems based on the principles of Good Manufacturing Practice (GMP) and the application of Hazard Analysis of Critical Control Point (HACCP) during feed production is necessary to avoid feed accident.

Keywords: medicated feed, salinomycin, anticoccidial, camel, toxicity

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292 Enhancing Seismic Performance of Ductile Moment Frames with Delayed Wire-Rope Bracing Using Middle Steel Plate

Authors: Babak Dizangian, Mohammad Reza Ghasemi, Akram Ghalandari

Abstract:

Moment frames have considerable ductility against cyclic lateral loads and displacements; however, if this feature causes the relative displacement to exceed the permissible limit, it can impose unfavorable hysteretic behavior on the frame. Therefore, adding a bracing system with the capability of preserving the capacity of high energy absorption and controlling displacements without a considerable increase in the stiffness is quite important. This paper investigates the retrofitting of a single storey steel moment frame through a delayed wire-rope bracing system using a middle steel plate. In this model, the steel plate lies where the wire ropes meet, and the model geometry is such that the cables are continuously under tension so that they can take the most advantage of the inherent potential they have in tolerating tensile stress. Using the steel plate also reduces the system stiffness considerably compared to cross bracing systems and preserves the ductile frame’s energy absorption capacity. In this research, the software models of delayed wire-rope bracing system have been studied, validated, and compared with other researchers’ laboratory test results.

Keywords: cyclic loading, delayed wire rope bracing, ductile moment frame, energy absorption, hysteresis curve

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291 Biomechanical Evaluation of the Chronic Stroke with 3D-Printed Hand Device

Authors: Chen-Sheng Chen, Tsung-Yi Huang, Pi-Chang Sun

Abstract:

Chronic stroke patients often have complaints about hand dysfunction due to flexor hypertonia and extensor weakness, which makes it difficult to open their affected hand for functional grasp. Hand rehabilitation after stroke is essential for restoring functional independence. Constraint-induced movement therapy has shown to be a successful treatment for patients who have acquired certain level of wrist and finger extension. The goal of this study was to investigate the feasibility of task-oriented approach incorporating 3D-printed dynamic hand device by evaluating hand functional performance. This study manufactured a hand device using 3d printer for chronic stroke. The experimental group engaged task-oriented approach with dynamic hand device, but the control group only received task-oriented approach. Outcome measurements include palmar pinch force (PPF), lateral pinch force (LPF), grip force (GF), and Box and Blocks Test (BBT). The results of study revealed the improvement of PPF in experimental group but not in control group. Meanwhile, improvement in LPF, GF and BBT can be found in both groups. This study demonstrates that the 3D-printed dynamic hand device is an effective therapeutic assistive device to improve pinch force, grasp force, and dexterity and facilitate motivation during home program in individuals with chronic stroke.

Keywords: 3D printing, biomechanics, hand orthosis, stroke

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290 Evaluation the Influence of Trunk Bracing in Joint Contact Forces in Subjects with Scoliosis

Authors: Azadeh Jafari, Mohammad Taghi Karimi, Azadeh Nadi

Abstract:

Background: Scoliosis is the lateral curvature of the spine which may influence the abilities of the subjects during standing and walking. Most of the scoliotic subjects use orthosis to reduce the curve and to decrease the risk of curve progression. There was lack of information regarding the effects of orthosis on kinematic and joint contact force. Therefore, this research was done to highlight the effects of orthosis on the aforementioned parameters. Method: 5 scoliotic subjects were recruited in this study, with single curve less than 40 (females with age 13.2 ± 1.7). They were asked to walk with and without orthosis. The kinematic of the joints, force applied on the legs, moments transmitted through the joints and joint contact forces were evaluated in this study. Moreover, the lengths of muscles were determined by use of computer muscle control approach in OpenSim. Results: There was a significant difference between the second peak of vertical ground reaction force while walking with and without orthosis (p-value < 0.05). There was no difference between spatiotemporal gait parameters while walking with and without orthosis (P-value > 0.05). The mean values of joint contact forces (vertical component) increased by the use of orthosis, but the difference was not significant (p-value > 0.05). Conclusion: Although the kinematic of most of the body joints was not influenced by the use of orthosis, the joint contact force may be increased by orthosis. The increase in joint contact force may be due to the performance of orthosis which restricts the motions of pelvic and increases compensatory mechanism used by the subjects to decrease the side effects of the orthosis.

Keywords: scoliosis, joint contact force, kinetic, kinematic

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