Effect of Dampers on Seismic Demand of Short Period Structures in Rock Sites

Seismic behavior of short period structures with dampers founded on rock is investigated. A single bay frame with diagonal damper that represents short period structures is evaluated in response to the excitation of a set of earthquake records. The frame system is modeled as a generalized single degree of freedom system, and is subjected to five earthquake records representative of rock site conditions. The relationship between the force modification factor and the global ductility demand for short period structures founded on rock, in the presence of dampers, tends to approach those of long period ones. Compared with seismic demand under general site conditions, short period structures founded on rock show less seismic demand and less sensitivity to earthquake excitations. Similar to seismic demand in general site conditions, dampers with high damping ratios for short period structures in rock sites tend to keep the structural response in the elastic range even for high values of force reductions. Seismic code provisions should be revised to account for short period effect under seismic excitation

Effect of Dampers on Seismic Demand of Short Period Structures

Seismic behavior of a single bay frame with diagonal damper that represents short period structures is evaluated in response to the excitation of a set of earthquake records. The frame system is modeled as a Generalized Single Degree of Freedom (GSDOF) system, and is subjected to nine earthquake records representative of the range of dominant site conditions. The relationship between the force modification factor and the global ductility demand for short period structures, in the presence of dampers, tends to approach those of long period ones. Dampers with high damping ratios tend to keep the structural response in the elastic range even for high values of force reductions. Seismic code provisions should be revised to account for short period effect under seismic excitation

The Great Pivot: The Profession of Counseling has Changed, Has Your Pedagogy?

The profession of counseling is impacted by more than mental health theories and models. COVID-19, external or adjacent industries, and technology have all left their imprint on the provision of competent and relevant counseling services. In general, most counselor educators were clinically trained prior to many of these influences. Which begs the question, if the profession has changed, should your pedagogy? This presentation introduced some of the challenges and opportunities in training clinicians impacted by these forces

Analytical Case Study of Seismic Performance of Retrofit Strategies for Reinforced Concrete Frames : Steel Bracing with Shear Links Versus Column Jacketing

The effectiveness of seismic retrofitting applied to enhance seismic performance is assessed for a five-storey reinforced concrete (RC) frame building structure as built in Jordan in mid 80s. The response of the structure is evaluated using nonlinear static and dynamic analysis with synthetic ground motion records for rock base. FEMA 356 criteria are used to evaluate the seismic performance of the case study building. Two approaches are used for seismic evaluation: global-level evaluation (drift values) and member-level evaluation using three performance levels (immediate occupancy, life safety and collapse prevention). Based on the seismic evaluation results, two possible retrofit techniques are applied to improve the seismic performance of the structure, including the addition of RC column jackets and the addition of eccentric steel bracing. SAP 2000 is used to perform linear and nonlinear dynamic analysis, whereas plastic hinge analysis is performed by Response 2000. This study shows that adding new structural elements as steel members to an existing RC building proves to be effective in enhancing performance and reducing cost than adding RC elements. Even more, the eccentric bracing proves to outperform the column jacketing drift limit, plastic hinge limit and cost effectiveness

Revitalisation endodontic treatment of traumatised immature teeth: a prospective long-term clinical study

Purpose Continuation of root development following revitalisation endodontics (RET) has been shown to be unpredictable with lower success rates in traumatised teeth. This study reports the outcomes for RET in traumatised teeth over a review period of 4 years. Methods A prospective uncontrolled study, where RET was performed on traumatised upper immature anterior teeth with necrotic pulps in 15 children (mean age = 8.3 years), was conducted. Patients were reviewed at 3, 9, 12, 24, and 48 months, where clinical and radiographic assessments were performed. At the last review appointment, patients and parents answered questions assessing their perception and acceptance of tooth colour change over time. McNemar’s Exact test and linear mixed model assessment were used to assess changes in pulpal electrical response and radiographic evidence of continuation of root development over time, respectively. Results There was 83.3% healing with no significant changes in EPT responses, and no significant changes in root lengths, while significant changes in root widths (p < 0.05) and root apex widths (p < 0.001) were found over time. Twenty-five percent of patients and 33% of parents felt that there were changes in tooth colour following RET over time. Conclusion Within the limitations of this study, traumatised teeth treated using RET showed no significant root lengthening, however, acceptable periapical healing, slow thickening of root dentinal walls, and rapid development of apical closure were evident over a period of 43 months. Using Portland cement and omitting minocycline, did not eliminate crown colour change following RET

The use of behaviour management techniques amongst paediatric dentists working in the Arabian region: a cross‑sectional survey study

Purpose The purposes of this study were to investigate paediatric dental practitioners’ training and confidence in using dental behaviour management techniques in the Arabian region and to assess the factors influencing the application of advanced behaviour management techniques. Methods: An online questionnaire was distributed to paediatric dental practitioners in the Arabian region. Data were analysed using descriptive statistics and Pearson Chi Square. Results A total of 113 responses were obtained. Of these, the majority were from Egypt (45%, n = 51). Just over half of the respondents were registered as specialists at the country where they were practicing paediatric dentistry (53%, n = 60). The use of behaviour management techniques varied amongst participants with tell-show-do (95%, n = 107) and positive reinforcement (89%, n = 101) being the most routinely used techniques. The majority of participants reported using voice control (83%) and parental separation (68%) techniques. Hand over mouth exercise (HOME) was only used by 24% (n = 27) of participants, whilst just over half of the participants, 53%, reported using protective stabilisation. A significant association was shown between country of practice, country of obtaining paediatric dental training, speciality status and the use of advanced behaviour management techniques, whilst confidence in using HOME and sedation were associated with work setting and country of practice, respectively. Conclusion The use of advanced behaviour management techniques was found to be high amongst respondents in the Arabian region. The lack of training in using these techniques, however, is of concern. Further assessment of the factors affecting the use of and confidence in applying advanced behaviour management techniques in the Arabian region is needed

Improved optical activation of ion-implanted Zn acceptors in GaN by annealing under N2 overpressure

We investigated the properties of ion-implanted GaN:Zn annealed under various conditions using photoluminescence (PL) and high resolution x-ray diffraction (HRXRD). Epitaxial GaN/sapphire of high optical quality was ion-implanted with a 1013 cm−2 dose of Zn+ ions at 200 keV. The sample was capped with 200 Å of SiNx and then diced into numerous pieces which were annealed under varied conditions in an attempt to optically activate the Zn. Annealing was performed in a tube furnace under flowing N2, an atmospheric pressure MOCVD reactor under flowing NH3 or N2, and under an N2 overpressure of 190 atm. The observed improvement in the optical quality of GaN:Zn annealed under N2 overpressure yields further insights into the trade-off between defect annealing and N loss from the GaN crysta

Method for vibration measurement in pipelines of residential buildings

The article is devoted to the problem of insufficiency and incompleteness of existing methods for measuring vibration in pipelines of residential buildings. Existing methods for measuring vibrations in pipelines are considered and their effectiveness is analyzed. The assessment of complexity, cost efficiency and accuracy of the existing vibration measurement methods is made. An improved method for measuring the vibration of a pipeline section with a tap based on the analysis of the trace of blurring a circular mark and the Doppler Effect is proposed. © Published under licence by IOP Publishing Ltd