Numerical Investigation of Cyclic Behavior of Angled U-shaped Yielding Damper on Steel Frames

Yielding dampers are often selected as a cost-effective solution for improving steel structures compared to other energy dissipation systems. The objective of this research study was to investigate the cyclic behavior of the angled U-shaped yielding damper (AUSYD) on a steel frame using numerical method. The numerical model was first verified using two experimental samples. Next, the influence of the number of dampers on the cyclic behavior of the steel frame was examined. The parametric model outcomes included energy dissipation, elastic stiffness, strength, and equivalent viscous damping ratio (EVDR). Additionally, an analytical equation was proposed for calculating the ultimate strength of the AUSYD, which correlated well with the experimentally obtained results. The study findings revealed that the increase in elastic stiffness and strength of the frame equipped with the AUSYD was nearly equivalent to the sum of the elastic stiffness and strength of the bare frame and its supplementary dampers. Furthermore, the results showed that models with 8 to 12 dampers had comparable energy dissipation and EVDR. Adding 8 dampers to the frame increased the energy dissipation and damping coefficient of the frame by 42% and 67%, respectively

Effectiveness of the 'Mesiodistal Guide Set' in Dental Implant Placement: A Clinical Trial

Objectives This study used a newly designed mesiodistal guide set to assess and compare the precision of the mesiodistal positioning of dental implants relative to adjacent teeth. The cost-effective and convenient guide set was compared to the conventional freehand surgery technique in partially edentulous patients. Methods The study enrolled 38 patients requiring at least one implant. Participants were divided into case and control groups, receiving 30 implants in each group: 10 in free-end areas, and 20 in single-tooth edentulous spaces. In the case group, implants were placed using the mesiodistal guide set, while the control group underwent the freehand procedure. The postoperative evaluation involved taking parallel periapical radiographs to measure distances and angles between the implants and adjacent teeth using Photoshop CS4. The data was rigorously analyzed using the Generalized Estimating Equations (GEE) method, a statistical technique for modeling clustered data, with statistical significance set at p<0.05. Results Measurements of the mesiodistal distances between implants and adjacent teeth showed reduced deviations in the case group, with statistically significant differences in mesial (P=0.001) and distal (P=0.036) distances. The tooth-supported area exhibited better outcomes compared to the free-end area. However, there were no significant differences in implant-tooth angulation, whether mesial (P=0.503) or distal (P=0.188). Conclusion The study indicated that the mesiodistal guide set offers practical guidance for positioning implants next to teeth in partially edentulous patients. This finding has significant practical implications, providing tangible evidence for the clinical application of the guide set. Despite some limitations, the findings fall within clinically acceptable parameters, and the guide set proved to enhance accuracy over the freehand method

Stretch-Shortening Cycle in Countermovement Jump: Exclusive Review of Force-Time Curve Variables in Eccentric and Concentric Phases

The importance of vertical jump in sport fields and rehabilitation is widely recognized. Furthermore, Force-Time variables of vertical jump are factors affecting jumping height. Exclusive review of each of this variables, in eccentric and concentric phases, can lead to a specific focus on them during jumping exercises. So, the aims of his study were to a) reviewing the relationship between force-time curve variables of eccentric and concentric phases with jump height and b) description of this variables in Iran national youth volleyball players society. This is an observational study. 12 elite volleyball player (Male, Iran national youth volleyball players, 17&amp;plusmn;0.7 years) have participated in this study. Correlation between Force-Time variables - included peak force (PF), relative peak force (RPP), peak power (PP), average power (AP), relative peak power (RPP), and Modified Reactive Strength Index (MRSI) - in eccentric and concentric phases and ultimate jump height has been studied. Results showed that the average power (r=0.7) and relative peak force (r=0.75) of concentric phase and MRSI (r=0.83) have significant correlation with ultimate jump height (JH). Relative peak power and average power of concentric phase can massively effect Jump Height in sports like volleyball, which vertical jump is an integral part of them. Focus on both of these factors, which has been studied in this research, in training programs, can improve athlete jump performance significantly.</jats:p

Explanation of Loneliness in the Elderly and Comparison With Psychosocial Development Theory: A Quantitative Study

Introduction: Loneliness is universal, still very subjective feeling, natural to all human beings and a subjective experience of isolation. Many people may be ashamed of talking about it or admitting they feel lonely, because they are afraid of being stigmatized. The purpose of this study was to explore elderly experiences of loneliness and comparison with the Erikson’s theory. Materials and Methods: this study was a qualitative research with content analysis approach. The research population was twelve elderly, aged 68-85 years who lived in Hamadan city. Sampling began purposefully and continued until data saturation. To collect data, interview was used. All interviews were tape recorded and transcribed immediately. Data was analyzed using content analysis method. Results: In total, 187 primary codes, 7 subcategories and 3 main categories were obtained in which, the 3 main categories were feelings of alienation, separation of favorite activities, and fatigue and sadness. Core category or shared meaning was regret with heavy. Conclusion: Loneliness is common in elderly and associated with adverse health consequences both from a mental and physical health points of view. Therefore, appropriate intervention strategies to reduce isolation using the Erikson’s psychosocial theory can improve elderly quality of life to achieve Ego integrity throughout the life

Relationships between force-time curve variables and jump height during countermovement jumps in young elite volleyball players

Background: The importance of vertical jumps has been extensively recognised in sports. Furthermore, the main indicator of success in vertical jumps is the attained height, however, there is lack of knowledge on how the eccentric and concentric force-time curve variables affect the jump height. Objective: The objective of this study was to assess the relationships between eccentric and concentric variables of the force-time curve and jump height in youth volleyball players. Methods: Twelve elite volleyball players (male, Iranian national youth volleyball players, 17 ± 0.7 years) have participated in this study. The correlations between the force-time variables, including the peak force, relative peak force, peak power, average power, relative peak power, peak velocity, and modified reactive strength index, of the eccentric and concentric phases and jump height have been assessed based on Pearson's correlation coefficient. Results: Results showed that the average power (r = .70, p = .034), relative peak power (r = .75, p = .029) and peak velocity (r = .98, p = .004) of the concentric phase and modified reactive strength index (r = .83, p = .014) significantly correlated with the jump height. Conclusions: Relative peak power and average power of the concentric phase are shown to affect jump height in young volleyball players, whereby the vertical jump is their integral part