Unconventional thinking in online laboratory school: fractions

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Two-Dimensional Flow and NOx Emissions in Deflagrative Internal Combustion Wave Rotor Configurations

A wave rotor is proposed for use as a constant volume combustor. A novel design feature is investigated as a remedy for hot gas leakage, premature ignition, and pollutant emissions that are possible in this class of unsteady machines. The base geometry involves fuel injection partitions that allow stratification of fuel/oxidizer mixtures in the wave rotor channel radially, enabling pilot ignition of overall lean mixture for low NOx combustion. In this study, available turbulent combustion models are applied to simulate approximately constant volume combustion of propane and resulting transient compressible flow. Thermal NO production histories are predicted by simulations of the STAR-CD code. Passage inlet/outlet/wall boundary conditions are time-dependent, enabling the representation of a typical deflagrative internal combustor wave rotor cycle. Some practical design improvements are anticipated from the computational results. For a large number of derivative design configurations, fuel burn rate, two-dimensional flow and emission levels are evaluated. The sensitivity of channel combustion to initial turbulence levels is evaluated

University-school collaboration as a tool for promoting pre-service mathematics teachers’ professional skills.

In this paper, we discuss pre-service mathematics teachers’ professional gains from a university-school collaboration where they were given opportunity to observe two teacher educators’ instructional practices in a 6th grade classroom, interact with students in one-to-one fashion and reflect on the teacher educators’ and their own practices. Three pre-service teachers out of nine volunteers attended all modelling and practice sessions for 20 weeks. The data collected through interviews, field notes, videos of both class activities and group reflections and written reflections. All nine pre-service teachers appreciated the value of working closely with students in a school setting rather than just observing the teachers. Furthermore, they gained experience about noticing students’ mathematical thinking and critically analyzing their own practices.Scopus - Affiliation ID: 6010507

Technology use: analysis of lesson plans on fractions in an online laboratory school

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Characterizaton of the vessel geometry, flow mechanics and wall shear stress in the great arteries of wildtype prenatal mouse

Introduction: Abnormal fluid mechanical environment in the pre-natal cardiovascular system is hypothesized to play a significant role in causing structural heart malformations. It is thus important to improve our understanding of the prenatal cardiovascular fluid mechanical environment at multiple developmental time-points and vascular morphologies. We present such a study on fetal great arteries on the wildtype mouse from embryonic day 14.5 (E14.5) to near-term (E18.5). Methods: Ultrasound bio-microscopy (UBM) was used to measure blood velocity of the great arteries. Subsequently, specimens were cryo-embedded and sectioned using episcopic fluorescent image capture (EFIC) to obtain high-resolution 2D serial image stacks, which were used for 3D reconstructions and quantitative measurement of great artery and aortic arch dimensions. EFIC and UBM data were input into subject-specific computational fluid dynamics (CFD) for modeling hemodynamics. Results: In normal mouse fetuses between E14.5-18.5, ultrasound imaging showed gradual but statistically significant increase in blood velocity in the aorta, pulmonary trunk (with the ductus arteriosus ), and descending aorta. Measurement by EFIC imaging displayed a similar increase in cross sectional area of these vessels. However, CFD modeling showed great artery average wall shear stress and wall shear rate remain relatively constant with age and with vessel size, indicating that hemodynamic shear had a relative constancy over gestational period considered here. Conclusion: Our EFIC-UBM-CFD method allowed reasonably detailed characterization of fetal mouse vascular geometry and fluid mechanics. Our results suggest that a homeostatic mechanism for restoring vascular wall shear magnitudes may exist during normal embryonic development. We speculate that this mechanism regulates the growth of the great vessels. © 2014 Yap et al

Evaluation of median mandibular flexure values in dentulous and edentulous subjects by using an intraoral digital scanner

PURPOSE. Mandibular flexure is a crucial phenomenon that may affect the success of rigid bilateral mandibular prosthetic treatment. The aim of this study was to determine the amount of median mandibular flexure (MMF) that occurs during mouth opening from anterior to posterior mandible in seven different regions, in different age and gender groups of both dentulous and edentulous subjects, using an intraoral digital scanner. MATERIALS AND METHODS. In this study, the mandibular arch of 56 dentulous and 35 edentulous individuals were scanned with an intraoral scanner at both the minimum mouth opening (MnMO) and the maximum mouth opening (MxMO). MMF values were calculated by subtracting the distance value at the MxMO from the distance between the reference points at the MnMO at seven different mandibular regions of dentulous and edentulous subjects. In addition, the left and right side MMF values were measured. All data were analyzed statistically (alpha = .05). RESULTS. MMF value increased linearly from anterior to posterior mandible in both dentulous and edentulous individuals. The differences in MMF values were not statistically significant according to side (left/right), age, or gender (P > .05). No significant differences were found between the mean MMF values of the same region in both dentulous and edentulous individuals (P > .05). CONCLUSION. MMF was seen in different regions of the mandibles of both edentulous and dentulous individuals measured at the MxMO. Mandibular flexure should be considered for the success and prognosis of the long-span and rigid prostheses

Soft-tissue material properties and mechanogenetics during cardiovascular development.

During embryonic development, changes in the cardiovascular microstructure and material properties are essential for an integrated biomechanical understanding. This knowledge also enables realistic predictive computational tools, specifically targeting the formation of congenital heart defects. Material characterization of cardiovascular embryonic tissue at consequent embryonic stages is critical to understand growth, remodeling, and hemodynamic functions. Two biomechanical loading modes, which are wall shear stress and blood pressure, are associated with distinct molecular pathways and govern vascular morphology through microstructural remodeling. Dynamic embryonic tissues have complex signaling networks integrated with mechanical factors such as stress, strain, and stiffness. While the multiscale interplay between the mechanical loading modes and microstructural changes has been studied in animal models, mechanical characterization of early embryonic cardiovascular tissue is challenging due to the miniature sample sizes and active/passive vascular components. Accordingly, this comparative review focuses on the embryonic material characterization of developing cardiovascular systems and attempts to classify it for different species and embryonic timepoints. Key cardiovascular components including the great vessels, ventricles, heart valves, and the umbilical cord arteries are covered. A state-of-the-art review of experimental techniques for embryonic material characterization is provided along with the two novel methods developed to measure the residual and von Mises stress distributions in avian embryonic vessels noninvasively, for the first time in the literature. As attempted in this review, the compilation of embryonic mechanical properties will also contribute to our understanding of the mature cardiovascular system and possibly lead to new microstructural and genetic interventions to correct abnormal development

Social intelligence at work and its implication for organizational identification:: a sectoral comparison

Since organizational identification is an important phenomenon for efficiency and productivity of the organization, its relationship with many variables has been examined. However, there is no study in the literature examining the relationship between organizational identification and social intelligence. Grounded in the Strong Ties Approach the object of study is to explore the relationship between social intelligence and organizational identification. Besides, the study aimed to determine whether the level of social intelligence and organizational identification vary or not according to the sector type. The study was designed with a quantitative research pattern and correlational research design. The sample is consisting of 306 public and private sector employees. The survey technique with a convenience sampling method was used to collect the data. The obtained data were investigated through statistical analysis software. Social intelligence has been studied both as a whole and with its dimensions named as social information processing, social skills, and social awareness. According to the regression analysis results; social intelligence as a whole and social skills have a significant and positive contribution to predicting organizational identification. However, the effect of social information processing and social awareness on organizational identification is not significant. Moreover, independent samples t-test suggests that the social intelligence and social skills levels of private-sector employees are higher than the same factor levels of the public sector. However, the level of employees' social information processing, social awareness, and organizational identification does not differ according to the sector type. The research also offers several theoretical and practical implications

Preservice teachers' math teaching anxiety in an online laboratory school

The purpose of this study was to examine preservice teachers’ math teaching anxiety, to explore the relationships between math teaching anxiety and several variables, and to understand how preservice teachers’ math teaching anxiety changed during eight-weeks of the Online Laboratory School (OLS) within a university. We administered the Math Teaching Anxiety scale with 14 items to 43 preservice teachers by adapting Hadley and Dorward’s (2011) scale. The results revealed that on average, preservice teachers had math teaching anxiety from “a little” to “a moderate amount” degree before the OLS and their math teaching anxiety did not significantly change during the OLS. Moreover, math teaching anxiety was only significantly correlated with the number of methods courses completed so far.Nisa

Enhancing prospective mathematics teachers’ noticing skills through online laboratory school activities

This study investigated how prospective mathematics teachers’ (PMT) noticing skills, (i.e., attending, interpretation, and decision-making) were influenced through online laboratory school (OLS) activities. OLS provided PMTs opportunities for online fieldwork and work with students. The activities included lesson planning with peers under the supervision of academicians and experienced teachers, teaching, reflection and getting feedback. PMTs’ reflections on a video-taped lesson served as the pre-post assessment of the intervention. Quantitative analyses of data indicated PMTs showed statistically significant improvement in both interpretation and decision-making. Attending, on the other hand, was improved but not in a statistically significant way.Temmu