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Seismic response of post-tensioned reinforced concrete beams
No full textPost-tensioning can be used in reinforced concrete beams of long-span moment-resisting frame systems. Such frames are designed using the structural behavior factors given for conventional reinforced concrete structures under the assumption of similar ductility levels. In this study, post-tensioned beams were experimentally investigated to examine their expected seismic behavior. For this purpose, an exterior post-tensioned beam-to-column joint was selected from a code-compliant designed prototype frame building to produce 1:2 scaled specimens. The key test variables were the presence of prestressing and the ratio of mild steel reinforcement. Accordingly, the base shear-lateral displacement, moment-curvature, crack width, dissipated energy, and stiffness degradation relations were obtained. Also, nonlinear finite element analyses were performed to simulate the behavior of the test specimens, consequently, a reasonable agreement between the numerical model and test results was observed upon selecting the steel cyclic model damage parameters appropriately. Then, the required amount of longitudinal rebar for target ductility was suggested through the parametric study calibrated with the experimental outputs of post-tensioned members. Apart from those, the section analysis procedure was followed to propose minimum mild steel ratio for bonded post-tensioned beams
Japan-like ribbon continent rifted from a Sumatra-like continental arc system: the Cimmerian Continent
No full textSince its existence was proposed in 1979, the majority of the authors assumed that the Cimmerian Continent had an Atlantic-type continental margin along its northern rim, in contrast to the original model. In this paper, which is a summary of a much longer paper (Şengör et al. 2023), we show that the regional geological data from the various preserved bits of the Cimmerian Continent clearly indicate that the northern margin of it was mostly of Pacific-type and in certain short distances, possibly of California-type. Our data, culled mostly from the published literature, consist mainly of reliable isotopic ages of magmatic rocks that we interpret as arc-related. We also used palaeontological data to understand the placement of the Cimmerian Continent during the Permian, when, it seems, it began parting company with the northern margin of Gondwana-Land. The main purpose of our paper is to show the great relevance of regional geological data when trying to understand geological processes and making reconstruction of former continental positions
Textile energy storage: Utilizing binary nickel cobalt metal-organic frameworks and polypyrrole-derived nitrogen-enriched carbons
No full textDeveloped as electrode-active materials, nickel‑cobalt bimetallic metal organic frameworks (MOFs) demonstrate impressive capacitive performance. In this study, highly porous Ni–Co MOFs were directly grown onto commercial cotton textiles (CTs) using a one-pot hydrothermal method. The MOF-decorated CTs underwent extensive electrochemical analysis, achieving a storage capacity of up to 132C g−1, comparable to conventional wearable supercapacitors. These textile electrodes exhibited remarkable cyclic stability, retaining approximately 90.6 % of their initial capacity after 5000 continuous charge-discharge cycles. Additionally, N-rich pyrolyzed polypyrrole carbons (NPPC) were utilized as negative electrodes on commercially available carbon cloths (CCs). We successfully engineered wearable asymmetric supercapacitors (WASCs) with commendable capacitances of 76C g−1, employing an alkaline polyvinyl alcohol gel electrolyte. The fabricated Ni–Co MOF@CT//NPPC@CC WASC devices demonstrated substantial energy storage capability (29.6 Wh kg−1) while maintaining exceptional power density (428 W kg−1) and long-term cycle stability, retaining 91 % of their initial capacitance after 5000 charge-discharge cycles. Given their remarkable capacitive behavior, these textile supercapacitors show great promise as high-performance wearable energy storage devices
Soil liquefaction sites following the February 6, 2023, Kahramanmaraş-Türkiye earthquake sequence
No full textSeismically induced soil liquefaction was listed as one of the major causes of damage observed in the natural and built environment during the 2023 Türkiye-Kahramanmaraş earthquake sequence. Reconnaissance field investigations were performed to collect perishable data and document the extent of damage immediately after the events. The sites with surface manifestations of seismic soil liquefaction in the form of soil ejecta, excessive foundation and ground deformations were identified and documented. The deformations were mapped, and samples from ejecta were retrieved. The ejecta samples were predominantly classified as sands with varying degrees of fines. Laboratory test results performed on liquefied soil ejecta revealed that the fines-containing liquefied ejecta samples are mostly classified as low plasticity clays (CL). Most of CL soil type ejecta were retrieved from Gölbaşı–Adıyaman region. The liquid limits of these samples varied in between 32 and 38%, their plasticity index values were estimated in the range of 16–23%. Surprisingly, two ejecta samples with plasticity indices higher than 30% were retrieved from Hatay airport, one of which was classified as high plasticity clay (CH). The majority of the fine-grained ejecta samples fall either on “Zone B: Testing Recommended” region of the Seed et al. (Keynote presentation, 26th Annual ASCE Los Angeles Geotechnical Spring Seminar, Long Beach, CA, 2003) susceptibility chart. Moreover, 12 out of 74 samples fall outside the susceptible limits defined by Seed et. These preliminary results suggest that clayey soils can produce liquefied ejecta when subjected to cyclic loading. Detailed site investigation and laboratory testing programs are ongoing to further investigate this rather unexpected response. Until their findings become available, the liquefaction susceptibility of silty-clayey soils’ mixtures is recommended to be assessed conservatively with caution
Is Need-Based Action Possible for Each Child?: Preschool Teachers' Differentiated Instruction Within Multicultural Classrooms
No full textDifferentiated instruction (DI) is a teaching philosophy which addresses the learning needs of individual children. This multiple case study aimed to investigate the extent preschool teachers differentiated content, process, assessment, and learning environment within multicultural classrooms. Four early childhood teachers' experiences were examined through observations, interviews, photographs, and field notes. It was found teachers used multiple strategies to differentiate their instructional process and content. Strategies of demonstration, providing physical support, peer observation, or repeating directions were prominent for concrete learning. Also, it was determined that teachers implemented several strategies such as using visual materials and activities, and/or diversifying the types of activities for similar topics to differentiate educational content in multicultural classrooms. Moreover, teachers used a limited number of strategies including managing time and resources flexibly as a means of differentiating the learning environment. Similarly, they rarely reported, nor were observed to differentiate assessment. Thus, teachers' differentiated practices, especially those based on learning environment and assessment, should be developed with effective educational policies. Overall, the value of this study is undeniable in terms of providing a perspective to be able to handle these challenges of educators in implementing culturally responsive education in different countries
Core-shell aerogel design for enhanced oral insulin delivery
No full textCurrent protein-based therapies often rely on intravenous and subcutaneous injections leading to patient discomfort due to the need for frequent administration. Oral administration route presents a more patient-friendly alternative, but overcoming the challenge of low drug bioavailability remains paramount. This limitation is primarily attributed to protein degradation in the harsh gastric environment, enzymatic breakdown, and poor intestinal permeability. With their unique properties, such as high porosity and surface area, and easy scalability, aerogels offer a promising platform for oral delivery of therapeutic proteins. This study focused on the development and characterization of both conventional and core–shell aerogels derived from natural polysaccharides for the oral delivery of insulin, utilizing Humulin R® U-100 as the insulin source for the first time. Aerogels were produced via supercritical carbon dioxide (sc-CO2) drying of alginate gel beads. Scanning Electron Microscopy (SEM) images confirmed that the core–shell aerogels had higher uniformity in size and a more well-defined porous structure in comparison to conventional aerogels. Structural differences of two alginate sources were evaluated by Fourier Transform Infrared (FTIR) spectroscopy. A notable difference in encapsulation efficiencies was observed between conventional (12 %) and core–shell (53 %) aerogels, highlighting the superior carrier characteristics of the latter ones. In vitro insulin release profiles from the core–shell aerogels demonstrated their potential suitability for delivering regular/short-acting insulin therapeutics since only 30 % of insulin was released in Simulated Gastric Fluid (SGF) after 120 min, whereas 60 % of insulin was released in Simulated Intestinal Fluid (SIF) within the first hour followed by a sustained release stage
Clients and carers: Healthcare professionals’ roles in medical device development processes in SMEs
No full textPurpose of the article: With the call for patient-centred healthcare, designers and healthcare professionals collaborate increasingly, as both health and design researchers advocate closer engagement between the two. Yet the existing literature is scarce in describing the actual roles taken up by healthcare professionals in these collaborations. Addressing this gap, this article investigates the participation of healthcare professionals in medical device development in SMEs. Materials and methods: The research context is Ankara, Turkey, where most design and development activities in medical sector are geared towards export substitution, undertaken with limited resources. The analysis is based on data gathered through semi-structured interviews with 32 professionals, including design professionals, managers, physiotherapists and engineers involved in the design of around 25 medical devices. Results and conclusion: This article identifies four main roles that healthcare professionals take in medical device development: business partners, expert users, mediators, and medical professionals. These roles entail diverse responsibilities with various objects of collaboration with designers, making significant contributions to medical design
Unveiling Genetic Basis Associated With Manganese Content in Turkish Common Bean (Phaseolus vulgaris L.) Germplasm Through a Genome-Wide Association Study
No full textMicronutrient deficiencies, such as manganese (Mn), pose significant global health risks, affecting millions of people worldwide and leading to serious health conditions. Biofortifying crops, notably common beans, offer a sustainable solution to combat these deficiencies. This study aimed to uncover the genetic basis associated with Mn content in Turkish common bean (Phaseolus vulgaris) germplasm through a genome-wide association study (GWAS), which is crucial for developing nutrient-rich bean varieties. Here, we examined variation among 183 common bean accessions, collected from 19 provinces of Turkey and identified the genetic basis linked to seed Mn content. Genotype by environment interaction significantly influenced Mn content (p < 0.05). The mean Mn content was observed 31.69 mg kg−1 across the germplasm. Bingol-16 had the lowest, while Malatya-59 had the highest Mn contents. Stability analysis was performed using the ‘STABILITYSOFT’ method and found 10 stable accessions. The cluster constellation plot was generated using JMP statistical software. A total of 7900 DArTseq markers were used for association analysis, identifying 16 markers across four chromosomes (Pv2, Pv5, Pv7 and Pv11). Notably, markers DArT-3374915 and DArT-3375187 exhibited consistent associations across different environments, making them promising candidates for Mn-focused breeding programmes. Gene annotation and interactome analysis, including BLAST searches and protein–protein interaction analysis, revealed associations of candidate genes with Mn concentration regulation, shedding light on potential mechanisms underlying Mn accumulation in common beans. Our findings lay a foundation for marker-assisted breeding efforts in common bean improvement
Metamaterials Based on a Gaseous Mixture: Analytical Modeling of Electrostriction Effect and Corresponding Brillouin Frequency Shift
No full textElectrostriction properties of a dilute gas mixture are analytically calculated and derived herein for the first time. Electrostriction in a gaseous mixture is expressed in a standard process based on the energy conservation law using the Lorentz-Lorentz model and a model for calculating the electrostriction is introduced. The internal interactions of the gaseous environment follow the ideal gas law. These relationships show that electrostriction can be controlled by changing the volume ratio of gases. Since, electrostriction is an essential parameter in determining the Brillouin scattering, the proposed modeling is a key theoretical method to control the Brillouin scattering in gases. According to the numerical results, it was found that the electrostriction coefficient is almost independent of the wavelength range. More importantly, the frequency shift induced in an N2-He gas mixture is independent of the volume fraction. E.g., in volume fraction of 0.3 and wavelength of 300 nm, if the volume fraction is increased by 20%, the electrostriction of the gas mixture (γmix) will change by 4.3%, but the frequency shift almost does not change. On the other hand, if the frequency varies by 20%, the frequency shift will change by 16%, but in practice γmix almost remains constant
Does dexmedetomidine induce bone regeneration in cranial defects in rabbits?
No full textDexmedetomidine has been shown to exert protective and curative effects on various tissues and organs in different pathological processes. This study aimed to investigate the effect of dexmedetomidine on the regeneration process after making holes in the parietal bones of rabbits. Twenty-four male Oryctolagus cuniculus rabbits were allocated to three groups, and an 8-mm circular parietal critical-sized bone defect was induced in each animal. Group_C (control) received saline; Group_LD (low dose) was given dexmedetomidine 2.75 µg/kg; Group_HD (high dose), dexmedetomidine 5.5 µg/kg; all were administered intraperitoneally for 7 days. After 8 weeks the bones were examined by micro-computed tomography (micro-CT) and histomorphometry. The results indicated that regeneration was improved in both the dexmedetomidine-treated groups. The lower dose increased the bone volume ratio (BV/TV) more than the higher dose. Trabecular thickness, connectivity value, and connectivity density were also higher in Group_LD than in Group_HD. Significant intramembranous ossification was observed in the dexmedetomidine-treated groups, and active osteoblasts were seen at the margins of new bone trabeculae. We conclude that dexmedetomidine, especially at the lower dosage, increases osteoblastic activity and regeneration quality