Teaching & Learning The Spanish Aspect Using Blogs and Wikis: An Exploratory Study

This study investigated the influence of asynchronous computer text based technologies on the students’ performance when learning the preterite and the imperfect aspects in Spanish. Two research questions guided the study: Research Question 1) Is there a difference in students’ achievement levels in Spanish preterite and imperfect between those using wiki technologies and those using blog technologies after controlling for pre-intervention achievement levels? and Research Question 2) Are there differences in satisfaction levels for students learning Spanish preterite and imperfect via blog technologies as compared to those learning via wiki technologies? Results indicate that there were not significant differences between students who use blog or wiki technologies on performance levels when controlling for pre-existing knowledge. Results also indicated that there were not significant differences in satisfaction levels between those students using a wiki and those using a blog. These results suggest that wikis and blogs are good potential tools that may facilitate the teaching and learning of problematic grammar structures in a narrative context

球面調和解析に基づくバイノーラル音空間合成法

要約のみTohoku University鈴木陽一課

New Field Testing Procedure For Measuring Residual Stress in Plain Concrete Pavements and Structures

Residual stresses in rigid pavements diminish a pavement's ability to sustain its designed load. When capacity is reduced by residual stress, a pavement is vulnerable to premature failure necessitating costly repairs or replacement. A test method for measuring residual stresses has already been developed for steel wherein a small hole is drilled adjacent to an affixed surface strain gage (ASTM E837 2008). Based on the geometry of the test procedure, the change in strain reading is correlated to a residual stress in the steel material. While rigid pavements are as detrimentally affected by the formation of residual stresses as steel, no similar testing method exists for concrete. Recent research conducted by the Federal Aviation Administration's (FAA???s) National Airport Pavement Test Facility (NAPTF) investigated the strain relaxation of cantilevered concrete beams when a blind-depth hole using core drilling is made in the vicinity of an affixed strain gage. Initial findings indicated that the testing procedure partially quantified the residual stresses. Research at the University of Illinois at Urbana-Champaign (UIUC) improved the testing procedure using cantilevered concrete beams by instead sawing a linear notch near one end of the strain gage and sawing two linear notches near both ends of the strain gage. Results for the doubly notched concrete beam proved to be a much improved method for measuring residual stresses when compared to the core-drilled test procedure. The current project further improved test procedures and completed additional lab and field testing on in-situ plain concrete pavements. The test procedure was altered in order to observe the strain relaxation in three directions while four saw cuts are made surrounding the strain rosette. When this area of concrete had been appropriately isolated from load-induced stresses, simple calculations determine the residual stress of the material. Three dimensional Finite Element Model (FEM) analyses of these tests further corroborates the findings suggesting that the residual stresses in plain concrete pavements can be reliably measured

球面調和解析に基づくバイノーラル音空間合成法

要約のみTohoku University鈴木陽一課

Using Web 2.0 to Learn the Spanish Pretérito and Imperfecto

The researcher contrasted recognition of the Spanish preterite andimperfect by students who used web 2.0 technology with those who usedelectronic workbook technology. Results reveal that the use of web 2.0technologies has a positive effect on learning the Spanish preterite andimperfect

Freeze-thaw environment of precast concrete crossties and effect of vibration on fresh materials

High performance concrete is typically designed to achieve high strength and low permeability. These suppositions lead practitioners to install high performance concrete in outdoor environments assured that members will remain durable over scores of years. One such outdoor environment is in railroad lines where timber ties (alternatively known as crossties or sleepers) are being replaced with high performance concrete crossties. Additionally, concrete crossties are being installed in burgeoning high speed rail networks across the United States of America. It has been observed, however, that these high performance concrete crossties are subject to multiple deterioration mechanisms including freeze-thaw damage. This early degradation in critical transportation infrastructure necessitates a better understanding of the durability of high performance concrete in wet, wintry climates. In particular, the concrete crossties have been found to degrade at the rail seat area where the crosstie is physically joined to the rail. Among several failure mechanisms, including abrasion and hydraulic pressure cracking, it is hypothesized that the dense configuration of the rail line, pad, clips, and crosstie leads to pooling of water at the underside of the pad. This stagnant water sits atop the concrete crosstie at the rail seat area and can permeate into the material leading to scaling and freezing-thawing damage in colder climates. In this study, the resiliency of high performance concrete crossties against freezing-thawing damage is assessed in a collaborative effort with researchers at Kansas State University and the University of Illinois at Urbana-Champaign. In this dissertation, specifically, the extent of internal moisture and temperature fluctuations of instrumented crossties installed in ballast is examined. Half-space approximations are applied to predict the fluctuation of internal conditions as affected by external environmental conditions. Additionally, this dissertation also examines the stability of chemically entrained air bubbles in fresh concrete when the fresh material is subjected to varying time and degree of vibration. The propagation and attenuation of the vibratory peak acceleration as a function of distance from the vibrating source and the volume content of aggregate is studied and compared against the extent of air loss and aggregate segregation as evidenced in polished, 2-dimensional sections. Summarily, the mutual instances of critical moisture saturation and freezing temperatures in concrete crossties are experimentally measured and predicted. The predictive models are modified to create a concrete crosstie freeze-thaw susceptibility index based on historical weather data. This susceptibility index better informs owners of concrete crosstie infrastructure of environmental design criteria for freezing-thawing damage potential. The vibratory experimental results lend insight into rheological phenomenon that can to enhanced guidelines for the consolidation of non-conventional concrete that optimizes compaction while mitigating the loss of entrained air and aggregate segregation. Taken together, these two research thrusts enhance the civil engineering community’s understanding of the durability and resiliency of high performance concrete exposed to cold climates

球面調和解析に基づくバイノーラル音空間合成法

要約のみTohoku University鈴木陽一課

Optimal power flow model for building integrated photovoltaic systems operating in the Andean range

This paper presents a novel model to evaluate the power output of a building integrated photovoltaic system (BIPVS) operating in the Andean Range.  The Optimal Power Flow (OPF) model optimizes the power output of the BIPVS within an electrical system without violating operational limits.  The model is validated with the experimental performance of a 6 kW BIPVS installed in Bogota, Colombia. The meteorological data affect the power flow. The model is evaluated under sunny and rainy days to characterize the photovoltaic array performance. The results showed that the AC PV-energy generation was 5,904 kWh/year for 2017 and that there is a correlation factor of 99.87% between the experimental power flow and the proposed model

Measurements of the pp → ZZ production cross section and the Z → 4ℓ branching fraction, and constraints on anomalous triple gauge couplings at √s = 13 TeV

Four-lepton production in proton-proton collisions, pp -> (Z/gamma*)(Z/gamma*) -> 4l, where l = e or mu, is studied at a center-of-mass energy of 13 TeV with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 35.9 fb(-1). The ZZ production cross section, sigma(pp -> ZZ) = 17.2 +/- 0.5 (stat) +/- 0.7 (syst) +/- 0.4 (theo) +/- 0.4 (lumi) pb, measured using events with two opposite-sign, same-flavor lepton pairs produced in the mass region 60 4l) = 4.83(-0.22)(+0.23) (stat)(-0.29)(+0.32) (syst) +/- 0.08 (theo) +/- 0.12(lumi) x 10(-6) for events with a four-lepton invariant mass in the range 80 4GeV for all opposite-sign, same-flavor lepton pairs. The results agree with standard model predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous ZZZ and ZZ. couplings at 95% confidence level: -0.0012 < f(4)(Z) < 0.0010, -0.0010 < f(5)(Z) < 0.0013, -0.0012 < f(4)(gamma) < 0.0013, -0.0012 < f(5)(gamma) < 0.0013