Development Of Finite Element Codes For Shear Wall Analysis

Shear wall is commonly employed as a principal element to resist lateral loads due to wind or earthquake forces. An accurate mathematical model for shear wall structure needs to consider the effect of all components in the system i.e. shear wall, foundation, and subsoil. In addition to the necessity for accurate modelling of shear wall-foundation-soil system, the model must be proficient to capture the structural response of the shear wall building-foundation-soil and it should also be computationally efficient. Furthermore, since shear wall is a key structural element which plays a major role to ensure stability of the shear building system under lateral loads, it is essential to consider the inelastic response of the shear wall buildings. With the tremendous advancement in computer technology several finite element software’s are commercially available to researchers and engineers. However, this would not serve the objectives of the research investigator. In this study, new elements have been developed, modified constitutive law has been proposed, new computational algorithm has been utilised. Furthermore, this investigation focuses on the development of effective and suitable modelling of reinforced concrete shear walls. The modelling includes physical and constitutive modelling. (a) Physical modelling Most suitable elements had been adopted and some new elements have been developed for physical modelling of shear wall structural systems. The elements used for the purpose of mathematical discretisation of the shear wall structural system are: • Modified optimal triangle (MOPT) element with drilling degree of freedom to represent the superstructure and foundation. This element was developed in this study. • Interface element to represent the interfacial characteristics between the foundation represented by MOPT element with three degree of freedom per node (top continuum) and bottom continuum i.e. soil media idealised as plane stress /plane strain problem with two degree of freedom per node. This element was developed to incorporate slip and separation at the interface. • Super elements are groups of elements which are used to represent different substructures domain. • Nine node shell element has been used to represent the superstructure-foundation. This element is multi-layer in nature to simulate the R/C structures. • Coupled finite and infinite elements were used to model the near and far field in the soil media. These elements were employed when the modelling of soil structure interaction is in mind.All the above elements have been formulated based on continuum mechanics principle. (b) Constitutive modelling The following constitutive law for different materials are used in the problem of shear wall building-foundation-soil system. • Concrete; nonlinearities arising due to crushing, cracking and plastic yielding of concrete in one or two directions have been considered. • Steel; the steel reinforcement is assumed to be in a uni-axial stress state and is modelled as a bilinear material with strain hardening • Soil; to account for the nonlinear behaviour of the soil media, the nonlinear elastic model has been used Based on the above physical and material modelling two finite element codes have been developed during the course of this study: (i) Two dimensional finite element analysis of shear wall (2DASW) The modified optimal triangle element, super element, interface element and the nonlinear elastic model with different numerical techniques are included in its elements technology library in this FE code. (ii) Three dimensional finite element analysis of shear wall (3DASW) The 3DASW finite element codes deals with constitutive nonlinearities due to concrete and steel. The multilayer shell and beam elements are available in the element library of this finite element program.Both above finite element codes are equipped with pre, post processing and animation graphic facilities. The codes have been written using FORTRAN language and they are working under FORTRAN-95 Power Station. Accuracy and efficiency of the finite element codes has been achieved by analysing several benchmark examples available in literature. The finite element discretisation of different numerical examples used for the verification purpose and also computational efficiency indicate that, the finite element mesh with coarse mesh and wide range of element aspect ratio using MOPT produced good results. The results show accuracy and fast rate-convergence of super element and MOPT. An attempt has been made to highlight the computational efficiency of the developed 2DASW finite element codes by analysing actual shear wall buildings i.e. with and without opening. Results in terms of displacements and stresses are compared with those of commercial packages such as SAP-2000 and STAAD-PRO. It was observed that the contour of stress distribution, calculated by STAAD-PRO, SAP 2000 and the present study show that FE code using the present MOPT element is comparable in predicting stress distribution in the shear wall, but the MOPT element display more precise stress at the connecting beams. Moreover, the stress distribution evaluated by the developed FE code based on MOPT element formulation with coarse FE mesh, agrees well with the stress distributions given by the commercial packages where fine mesh was used. This comparison further proves the computational efficiency of the proposed formulation of the MOPT element.The validation of the 3DASW finite element has been made by analyzing a series of reinforced concrete (RC) structures studied by earlier researchers experimentally or analytically. The response of the RC structures in terms load–deflection curve, cracking pattern and prediction of ultimate load have been compared. It was found that the results predicted by 3DASW compared reasonably well with those reported in the literature. An extensive study has been carried out with respect to two dimensional analysis of shear wall-foundation-soil system subjected to vertical and lateral loading. It was observed that the displacement predicted by both linear and nonlinear interactive analyses showed remarkable differences in the values of displacement and stress distribution in the shear wall. This can be attributed to stress dependant nature of the tangent modulus. The computed displacement and stresses in nonlinear interactive analysis are further increased when compared to the linear interactive analyses. The effect of the shear wall building –foundation –soil interaction cannot be overlooked. The application of the 3DASW has been further enhanced by carrying out the inelastic analysis of the shear wall building. It was observed that; (i) Cracking patterns were initiated at the tension side at base of the wall and then spread across width and height of the wall. (ii) The cracking of concrete has significant influence on redistribution of normal stress σy. That is narrowing the zone of compression stress and transfer higher stress to un-cracked zone and reinforcement bars. (iii) Predefined target displacement is very helpful in proper prediction of load deflection curves

Investigation of glass-ceramic composites containing CeTi2O6 and CaZrTi2O7 for immobilization of nuclear waste

Glass-ceramic composite materials are being investigated for numerous applications (i.e. textile, energy storage, nuclear waste immobilization applications, etc.) due to the chemical durability and flexibility of these materials. The objective of this thesis was to understand the interaction of brannerite or zirconolite-type crystallites within the glass matrix and to investigate how the local structure of these composite materials changed with changing synthesis conditions as well as to study the structural stability of these materials upon irradiation. Borosilicate and Fe-Al-borosilicate glass-ceramic composites containing brannerite (CeTi2O6) or zirconolite (CaZrTi2O7) crystallites were synthesized at different annealing temperatures. Powder X-ray diffraction (XRD) and Backscattered electron (BSE) microprobe images have been used to study how the ceramic crystallites dispersed in the glass matrix. X-ray absorption near edge spectroscopy (XANES) spectra were also collected from all glass-ceramic composite materials. Examination of XANES spectra from the glass-ceramic composites have shown that the annealing temperature, glass composition, and the loading of the ceramic crystallites in the glass matrix can affect the local environment of the glass-ceramic composite materials. Radiation induced structural damage has been simulated by bombarding (implanting) the glass-ceramic materials using 2 MeV Au- to understand how the structure of a composite wasteform responds to the radioactive decay of incorporated nuclear waste elements. A combination of ion implantation and GA-XANES has been used to investigate the structural stability of glass-ceramic composite materials. Surface sensitive glancing angle XANES (GA-XANES) spectra were collected to selectively probe the damaged surface layer of the ion implanted materials. Examination of Ti K-edge GA-XANES spectra from ion implanted glass-ceramic composite materials have shown that ion implantation damaged the structure of the ceramics in the composite materials. However, the study of Si L2,3-edge XANES spectra from the ion implanted composite materials showed that ion implantation does not appear to damage the glass structure in these composite materials. A comparison of the glass-ceramic composites containing brannerite or zirconolite crystallites has shown that similar changes in the long-range and local structure of these composite materials occur when the synthesis conditions to form these materials are changed and/or after ion implantation

Cone-Beam Computed Tomographic Assessment of Mandibular Condylar Position in Patients with Temporomandibular Joint Dysfunction and in Healthy Subjects

Statement of the Problem. The clinical significance of condyle-fossa relationships in the temporomandibular joint is a matter of controversy. Different studies have evaluated whether the position of the condyle is a predictor of the presence of temporomandibular disorder. Purpose. The purpose of the present study was to investigate the condylar position according to gender in patients with temporomandibular disorder (TMD) and healthy controls using cone-beam computed tomography. Materials and Methods. CBCT of sixty temporomandibular joints in thirty patients with TMD and sixty joints of thirty subjects without TMJ disorder was evaluated in this study. The condylar position was assessed on the CBCT images. The data were analyzed using Pearson chi-square test. Results. No statistically significant differences were found regarding the condylar position between symptomatic and asymptomatic groups. Posterior condylar position was more frequently observed in women and anterior condylar position was more prevalent in men in the symptomatic group. However, no significant differences in condylar position were found in asymptomatic subjects according to gender. Conclusion. This study showed no apparent association between condylar positioning and clinical findings in TMD patients

Investigation of CeTi2O6- and CaZrTi2O7-containing glass–ceramic composite materials

NSERCGlass–ceramic composite materials are being investigated for numerous applications (i.e., textile, energy storage, nuclear waste immobilization applications, etc.) due to the chemical durability and flexibility of these materials. Borosilicate and Fe–Al–borosilicate glass–ceramic composites containing brannerite (CeTi2O6) or zirconolite (CaZrTi2O7) crystallites were synthe- sized at different annealing temperatures. The objective of this study was to understand the interaction of brannerite or zirconolite-type crystallites within the glass matrix and to investigate how the local structure of these composite materials changed with changing synthesis conditions. Powder X-ray diffraction (XRD) and Backscattered electron (BSE) microprobe images have been used to study how the ceramic crystallites dispersed in the glass matrix. X-ray absorption near edge spectros- copy (XANES) spectra were also collected from all glass–ceramic composite materials. Examination of Ti K-, Ce L3-, Zr K-, Si L2,3-, Fe K-, and Al L2,3-edge XANES spectra from the glass–ceramic composites have shown that the annealing temperature, glass composition, and the loading of the ceramic crystallites in the glass matrix can affect the local environment of the glass–ceramic composite materials. A comparison of the glass–ceramic composites containing brannerite or zirconolite crystallites has shown that similar changes in the long range and local structure of these composite materials occur when the synthesis conditions to form these materials or the composition are changed

A randomized field trial for the primary prevention of osteoporosis among adolescent females: Comparison of two methods, mother centered and daughter centered

Background: Osteoporosis is a serious public health. Since the majority of bone mass occurs during adolescence, primary prevention is important. Probably mother's participation in health education interventions leads to promote health behaviors in children. Aims: To assess a lifestyle modification intervention focused on mothers and students has an impact on osteoporosis preventive behaviors in adolescent girls. Materials and Methods: It is a randomized field trial in female high schools. 210 girls aged between 11 and 15 were randomly selected. Students in groups A and C and mothers in group B were selected Through the sampling frame. Our lifestyle modification was based on group based education in the public girls' high schools. Subjects in the intervention groups participated in three educational sessions. Students' osteoporosis preventive behaviors were measured by using a lifestyle questionnaire consisting of items assessing nutrition, physical activity and sun exposure. Repeated measure ANOVA at baseline, 4 week, 2 months and 6 months and were used to analyze the data. Results: After 1 month, diet and sun exposure scores increased significantly (P < 0.001) but it was higher in group B compared with group A. (About diet P < 0.001 and sun exposure = 0. 001). After 6 months, diet and sun exposure status in the group A approximately decreased to baseline, while in group B, diet components were significantly different compared to baseline (P < 0.001). There was no change in physical activity. Conclusion: Osteoporosis prevention intervention of adolescent can be effective when parents or girls participate in training sessions, but education is associated with better outcomes when focused on mothers

The effect of psyllium on fasting blood sugar, HbA1c, HOMA IR, and insulin control: a GRADE-assessed systematic review and meta-analysis of randomized controlled trials

There is equivocal evidence that psyllium can prevent or attenuate increases in fasting blood sugar. Therefore, this systematic review and meta-analysis sought to investigate the influence of psyllium on hemoglobin A1C (HbA1c), fasting blood sugar (FBS), insulin, and Homeostatic Model Assessment of Insulin Resistance (HOMA IR). We searched PubMed, ISI Web of Science (WOS), and Scopus for eligible publications, up to 15 July 2022, including randomized controlled trials (RCT) assessing the effect of psyllium on HbA1c, FBS, insulin, and HOMA IR levels in adults. Using a random effects model, we report the weighted mean differences (WMD) with 95% confidence intervals (CI). In this article, 19 RCT studies, consisting of 962 participants, were included. Psyllium significantly decreased FBS, HbA1c, and HOMA IR levels, but not insulin levels, as compared to placebo (FBS: WMD): -6.89; 95% CI: -10.62, -3.16; p &lt; .001), HbA1c: (WMD: -0.75; 95% CI: -1.21, -0.29; p &lt; .001), HOMA IR: (WMD: -1.17; 95% CI: -2.11, -0.23; p &lt; .05), and insulin: (WMD: -2.08; 95% CI: -4.21, -0.035; p &gt; .05)). Subgroup analyses illustrated differences in the effects of psyllium on FBS: dosages less than and more than 10 g/d showed significant differences (p value &lt; 0.05). However, it was not significant in intervention durations less than 50 days (p value &gt; 0.05). For HbA1c: psyllium consumption less than 10 g/d (p value &gt; 0.05) was non-significant. For HOMA IR and insulin: no significant changes were noted with psyllium consumption less than vs. more than 10 g/d. In conclusion, we found that psyllium could significantly decrease FBS, HbA1c, and HOMA IR levels, but not insulin levels, as compared to placebo

Non-linear soil structure interaction of shear wall system with super element

Shear wall is commonly employed as a principal element to resist lateral loads due to wind or earthquake forces. An accurate model for shear wall system needs to consider the effect of all components for analyses i.e. shear wall, foundation and subsoil. This investigation presents modeling of shear wall structure - foundation and soil system using the super element, finite and infinite elements after considering soil nonlinearity. A finite element program has been written based on the proposed physical and material model for the analysis of the system. The applicability of the proposed idealization has been shown by analyzing a shear wall structure under static loading. In order to explore the efficiency of using super elements, an attempt has also been made to model the shear wall building using fully conventional finite element discretization. Furthermore the paper investigates the necessity of including soil structure interaction in analyzing shear wall structures. The results obtained from the analysis of shear wall model considering five different types of soil for the soil media show that the influence of soil interaction is very significant in the displacement as well as stresses induced in shear wall. Furthermore this investigation highlighted the effect of considering nonlinearity of soil in total displacement and stresses in shear wall system

Serum leptin level has a positive correlation with BMI and creatinine clearance in CAPD patients

Objective: In a cross sectional study, 75 patients (42 males and 33 females) on continuous ambulatory peritoneal dialysis (CAPD) were enrolled from October 2007 to February 2008. Serum levels of leptin, albumin, triglyceride, dialysis adequacy (total KTN), renal creatinine clearance (Cr Cl), mid arm circumference and demographic findings were measured in all patients. Results: The mean age of patients was 53+/-14.76. The history of hemodialysis was seen in 23 patients. Mean serum leptin level in women and men were 27+/-23 mu g/l and 16+/-13 mu g/l, respectively. A significant correlation of serum leptin level with body mass index (BMI) (p0.05). Conclusions: To our knowledge, this is probably the first study to report that serum leptin level has a direct positive correlation with renal Cr Cl in CAPD patients. This may explain the increase in mortality in patients with lower serum leptin levels (Tab. 2, Fig. 2, Ref. 25). Full Text in PDF www.elis.sk

DICOM Data Transfer of Radiology Images based on Publish-Subscribe Software Architecture

Introduction: Various methods have been introduced for the offline exchange of radiological images between medical centers using technologies such as CD or E-mail. Costly infrastructures such as PACS have also been introduced to exchange images in a medical center. But these methods or dedicated networks between various centers are practically impossible.Methods: In this observational study, publish-subscribe software architecture is presented to facilitate communication between medical centers, considering the challenge of scalability. This approach transfers the images in DICOM format to the publish/subscribe server. Other medical centers receive the images by subscribing to this service and specifying their interesting images.Results: The simulation results of this architecture on a data set of DICOM images and the number of publishers and subscribers showed that the system’s response time does not increase much   and it maintains an appropriate data transfer speed while the number of users increases. For this reason, it has good scalability.Conclusion: Implementing the publish-subscribe architecture showed that eliminating the dependency between imaging and medical centers makes implementing and interacting with users easier. From this point of view, this architecture has excellent potential to create an infrastructure for sharing images between medical centers