4,628 research outputs found
Ultrasonic Laboratory Study of Full Waveform Acoustic Logs in Boreholes with Fractures
No full textA set of ultrasonic experiments was carried out to determine the effects of horizontal and vertical fractures on full waveform acoustic logs. Boreholes of 1 cm diameter were drilled in aluminum blocks. Measurements were made with horizontal fractures of 0.05 mm, 1.0 mm, 2.5 mm, and 4.5 mm width and a vertical fracture of 1.0 mm width. The horizontal
fractures of even the smallest thickness significantly attenuate the P, S, and pseudo-Rayleigh waves. The Stoneley waves are the least attenuated, and attenuation increases
with increasing fracture width. The vertical fracture attenuates Stoneley waves most
significantly. Both scattering and fluid flow playa role in attenuation. The results may
qualitatively be extended to inclined open fractures, where we expect strong attenuation
of P and S waves and moderate attenuation of Stoneley waves.Massachusetts Institute of Technology. Full Waveform Acoustic Logging Consortiu
Temperature-dependent absorption edge and photoconductivity of Tl2In2S3Se layered single crystals
No full textUsing Generalizability Theory to Examine Different Concept Map Scoring Methods
No full textConclusions and Recommendations: According to the results of this study, Phi coefficient was higher in the concept map study in which the holistic scoring method was used. In this study, tasks represented a significant variance component for both scoring methods. This may be interpreted to mean that the levels of difficulty for the tasks differed according to the students using both methods. In each of the scoring methods, the variance related to the raters was found to be zero, which may result in the interpretation that raters scored the maps consistently.Findings and Results: In focusing on the size of the variance estimates according to holistic scoring methods, while the student component (objects of measurement) accounts for one of the largest percentages of th
Reaching Rigor for English Learners Through Responsive Interactions of Care
No full textCitation: Holmes, M., Kavimandan, S., & Herrera, S. (2018). Reaching rigor for English learners through responsive interactions of care. In N. Guler (Ed.), Optimizing elementary education for English language learners (pp. 91-115). Hershey, PA: IGI Global.This chapter explores what happens when teacher-student and student-student interactions reflect a higher level of responsiveness to the human beings involved. It describes biography-driven instruction (BDI), a research-based method of instruction that supports all learners to reach high academic standards, while at the same time ensuring that English learners have the scaffolds and tools needed to engage fully in the curriculum. Teachers who implement BDI develop a holistic understanding of students' sociocultural, linguistic, cognitive, and academic dimensions. They use students' background knowledge as a springboard to new learning. To determine the impact of BDI on the education of English learners in elementary classrooms, this chapter explores the perspectives of 16 teachers (Grades 1-6) who received professional development on BDI and then implemented the method with their own communities of learners. Interview data was collected in Spring 2016, transcribed, and qualitatively analyzed. Findings in the form of themes in participant voice are discussed throughout the chapter
Effects of functional strength training on functional movement and balance in middle-aged adults
No full textFunctional movement deficiencies cause falls and injuries in adults. Functional strength training (FST) is emerging as a new training method for athletes, middle-aged and older adults, to improve functional movement: The present study was conducted in order to investigate the effects of FST on balance and functional movement in healthy and independent middle-aged adults. The sample for this study consisted of 46 physically active individuals (24 female and 22 male). A total of 46 subjects were divided based on randomly into the functional strength training (FST) group (n = 26) aged: 51.55 ± 3.73 years; height: 168.69 ± 8.8 cm; body mass: 75.88 ± 12.18; and traditional strength training (TST) group (n = 20) age: 52.85 ± 4.01; height: 166.9 ± 9.98; body mass: 76.15 ± 10.45. Each group performed 24 sessions of a training protocol three-time a week. The functional movement was assessed using the functional movement screen (FMS) protocol. Balance performance was determined by using the balance error scoring system (BESS). Bodyweight and body fat ratio were measured using bioelectric impedance. There was a significant statistical difference between FMS total scores after an eight-week FST in the FST group. After the intervention, the functional strength group tended to have significantly better balance control than the traditional strength group (p = 0.01). Statistically, significant differences were observed between pre-test and post-test in the intervention group on BMI, body fat, and body mass (p = 0.01). There were not found significant differences in balance control and FMS score in TST group. As a result of this study, FST positively affected the FMS total score and balance performance in middle-aged adults. Early detections of the deficiencies in functional movement and balance in the middle ages may reduce the risk of insufficiency and fall in adults through targeted functional strength training intervention
Notes on Comparison of Covariance Matrices of BLUPs Under Linear Random-Effects Model with Its Two Subsample Models
No full textA general linear random-effects model that includes both fixed and random effects, and its two subsample models are considered without making any restrictions on correlation of random effects and any full rank assumptions. Predictors of joint unknown parameter vectors under these three models have different algebraic expressions. Because of having different properties and performances under these models, it is one of the main focuses to make comparison of predictors. Covariance matrices of best linear unbiased predictors (BLUPs) of unknown parameters are used as a criterion to compare with other types predictors due to their definition of minimum covariance matrices structure. The comparison problem of covariance matrices of BLUPs under the models is considered in the study. We give a variety of equalities and inequalities in the comparison of covariance matrices of BLUPs of a general linear function of fixed effects and random effects under the models by using an approach consisting matrix rank and inertia formulas
Metal-Salt Enhanced Grafting of Vinylpyridine and Vinylimidazole Monomer Combinations in Radiation Grafted Membranes for High-Temperature PEM Fuel Cells
No full textProton exchange membranes were prepared and characterized for utilization in high-temperature proton exchange membrane fuel cells, HT-PEMFCs. 1-vinylimidazole (1-VIm) and 4-vinylpyridine (4VP) monomers were simultaneously grafted onto pre-irradiated ETFE (ethylene-co-tetrafluoroethylene) films which were prepared using γ-rays with a dose of 100 kGy, as a robust substrate to prepare acid-base composite membranes. The grafting reaction was performed at 60 °C for 24 h followed by protonation via phosphoric acid doping in the subsequent step. The effect of adding ferrous salts as promoters in grafting was investigated by characterization of resultant membranes via thermal gravimetric analysis and mechanical tests. The fuel cell tests were conducted under different relative humidities (RHs) and applied temperatures. Membranes prepared with salt addition exhibited superior proton conductivities. Results including up to 80 mS cm-1 conductivity at 110 °C in 60% RH and excellent thermal stability, even at 300 °C, suggest these membranes are promising for HT-PEMFC applications
New generation radiation-grafted PVDF-g-VBC based dual-fiber electrospun anion exchange membranes
No full textAnion Exchange Membranes (AEM) have the potential to solve the cost issues of fuel cell technologies due to their basic environment that can allow the use of cheaper components. However, there is still a need to develop an ideal inexpensive, mechanically robust AEM with high ionic conductivity and ion exchange capacity (IEC). In this work, we present various dual-fiber electrospun membranes based on a novel radiation-grafted copolymer. First, the synthesis route of radiation-induced grafting of vinyl benzyl chloride (VBC) onto poly (vinylidene fluoride) (PVDF) to prepare PVDF-g-VBC was optimized. Then, PVDF-g-VBC powders were used to fabricate dual-fiber electrospun mats with inert PVDF and commercial Fumion-FAA-3 ionomer. Dual-fiber electrospun mats were hot-pressed and then quaternized with trimethylamine. Finally, mechanical properties, ion exchange capacity, ionic conductivity, and morphology of these prepared dual-fiber electrospun membranes were investigated. The dual-fiber membrane prepared with PVDF-g-VBC (88% of the total weight of the membrane) and PVDF: Fumion-FAA-3 (1:2) mix (12 wt%) realized ionic conductivity of 4.67 mS/cm at 25 °C, high ion exchange capacity of 1.35 mmol/g with Young's Modulus of 761 MPa. The membrane based on the combination of radiation grafting and dual-fiber electrospinning was prepared for the first time in literature and offers the prospect of tuning and fine-control of mechanical and physicochemical properties of AEMs
The association between sarcopenic obesity and malnutrition in community-dwelling older adults
No full textBackground The increase in fat tissue and the decrease in muscle mass with advancing age have prompted researchers to explore the coexistence of sarcopenia and obesity, i.e. sarcopenic obesity (SO). SO may lead to malnutrition due to poor diet quality, while malnutrition may contribute to SO by causing further muscle loss and metabolic imbalances.Objectives The aims were to investigate: (i) the prevalence of SO in community-dwelling older adults, (ii) the diagnostic ability of two different malnutrition methods, and (iii) the association between SO and malnutrition.Methods Community-dwelling older adults (>= 65 years) were invited to participate. SO assessment was conducted based on the ESPEN/EASO consensus criteria. Malnutrition was evaluated based on both the Global Leadership Initiative on Malnutrition (GLIM) criteria and the Mini-Nutritional Assessment (MNA).Results Five hundred and ninety older adults (69.3% women, mean age: 74.31 +/- 6.55 years) were included in the study. The overall prevalence of SO was 5.9% (n = 35). The prevalence of malnutrition was 23.9% according to the GLIM criteria, while it was 3.1% according to MNA. The agreement between the two measurements was & kgreen; = 0.32. There was no association between SO and malnutrition based on either GLIM (P: .06, OR: 1.971, 95% CI: 0.966-4.024) or MNA (P: .948, OR: 1.934, 95% CI: 0.119-7.306).Conclusions Even though the agreement for diagnosing malnutrition between GLIM criteria and MNA was fair, the number of participants diagnosed with malnutrition by GLIM criteria was almost eight times higher than MNA. No association was established between SO and malnutrition defined by GLIM or MNA.Clinical trial number NCT05122104.The authors would like to thank the participants for participating in this research
Radiocarbon dating of archaeological and geographical samples and their evaluation
No full textVarious samples obtained from different places in Anatolia were dated using radiocarbon technique. The results of unknown aged archaeological samples were chronogically evaluated. The wood and charcoal samples taken from archaic mine galleries showed that development of mining dates back to 2000 B.C. in Anatolia, Shells found around Konya plain proved that this place was occupied by a lake and the dates suggest that the lake level attained its maximum 20.000 years ago, and it possibly dried 14.000 years ago,Différents échantillons obtenus de divers sites d'Anatolie ont été datés par la technique du radio- carbone. Les résultats concernant des échantillons archéologiques d'âge inconnu sont évalués chronologiquement. Des échantillons de bois et de charbon pris dans des galeries de mines antiques montrent que le développement de l'art des mines remonte vers 2000 B.C. en Anatolie. Des coquilles découvertes autour de la plaine de Konya prouvent que cette zone était occupée par un lac et les dates suggèrent que le niveau de ce lac atteignit son maximum il y a 20,000 ans, et il s'assécha peut-être il y a 14.000 ans.Ergin M., Kis M., Guler R. Radiocarbon dating of archaeological and geographical samples and their evaluation. In: Revue d'Archéométrie, n°4, 1980. pp. 73-76
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