Technology-enhanced learning as a site for interdisciplinary research

This briefing on Interdisciplinary Research is the fifth publication of its kind emerging from the Technology Enhanced Learning Research programme (TEL). TEL is a £12m programme running from 2007-2012 with eight large interdisciplinary projects aiming to combine technological and pedagogical expertise to improve outcomes for learners. The programme is funded jointly by the UK’s Economic and Social Research Council and Engineering and Physical Sciences Research Council. TEL also commissions analyses of key theoretical, practical and policy issues across and beyond the eight projects, and in the wider TEL field

The Challenges of Capacity Building in the Aligning Forces for Quality Alliances

Summarizes the challenges and trade-offs in infrastructure and governance as well as stakeholder relations and participation, such as inclusive versus efficient decision making, in an alliance to coordinate regional healthcare improvement activities

Aligning product and supply chain strategies in the mobile phone industry

Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 87-88).Designing and managing the supply chain of a company in the mobile phone industry is particularly challenging. Short product lifecycles, rapidly evolving technology, globally linked distribution networks, increasing product variability and high levels of demand and supply uncertainty all create problems for those managing these supply chains. As competition in this industry increases and profit margins decrease, proper supply chain management practices will only become more important to companies competing in this industry. In order to succeed, companies must implement their supply chain so that it effectively supports their corporate strategy. This thesis investigates the relationship between corporate strategy and supply chain strategy within the mobile phone industry. Although it is directed at one industry, the wide variety of products in terms of price and functionality suggests that there isn't a "one size fits all" supply chain strategy appropriate for all companies that produce mobile phones. An extensive survey was developed that asks participants strategic, tactical and operational questions about different aspects of supply chains that deliver mobile phones. This is used to identify areas in which the stated supply chain strategy impacts the design and operation of the supply chain. Finally, differences in supply chain practices between high and low performers are identified based on supply chain strategy.by Robert Scanlon.S.M

Predictions of Groundwater Levels and Spring Flow in Response to Future Pumpage and Potential Future Droughts in the Barton Springs Segment of the Edwards Aquifer

A two-dimensional numerical groundwater-flow model was developed for the Barton Springs segment of the Edwards aquifer to evaluate groundwater availability and predict water levels and spring flow in response to increased pumpage and droughts from 2000 through 2050. A steady-state model was developed on the basis of average recharge for a 20-yr period (1979 through 1998) and pumpage values for 1989. Hydraulic conductivity zones (10) were adjusted to obtain good agreement between measured and simulated hydraulic heads. Zones of hydraulic conductivity ranged from 1 to 1,000 ft/d. We conducted transient simulations using recharge and pumping data for a 10-yr period from 1989 through 1998 that includes periods of low and high water levels. Good agreement was found between measured and simulated flow at Barton Springs (root mean square error [RMSE, average of squared differences in measured and simulated discharges] 17 cfs) and between measured and simulated water levels in many of the monitoring wells (mean RMSE 40 ft). The simulation results overestimate spring discharge by about 10 cfs during low flow periods. To assess the impact of future pumping and potential future droughts on groundwater availability, we conducted transient simulations using extrapolated pumpage for a 10-yr period (2041 through 2050) and using average recharge for a 3-yr period and recharge from the 1950s drought for the remaining 7 yr. Results for this scenario predict that flow in Barton Springs will become very low ( 4 cfs) toward the end of the drought. Because of the bias in the simulation results, the combination of drought and future pumpage could result in no discharge at Barton Springs. Additional scenarios were simulated that included current pumpage and no pumpage. These simulations indicate that with current pumpage, spring discharge will decrease to levels similar to those calculated for the end of the 1950s drought (11 cfs). No pumpage resulted in discharges as low as 17 cfs. Actual flows, which may be about 7 cfs because of the bias in the simulation results, indicate that drought conditions similar to those of the 1950s will require no pumpage if spring discharges similar to those of the 1950s are to be maintained.Bureau of Economic Geolog

Anion Distribution, Structural Distortion, and Symmetry-Driven Optical Band Gap Bowing in Mixed Halide Cs2SnX6 Vacancy Ordered Double Perovskites.

Mixed anion compounds in the Fm3̅m vacancy ordered perovskite structure were synthesized and characterized experimentally and computationally with a focus on compounds where A = Cs+. Pure anion Cs2SnX6 compounds were formed with X = Cl, Br, and I using a room temperature solution phase method. Mixed anion compounds were formed as solid solutions of Cs2SnCl6 and Cs2SnBr6 and a second series from Cs2SnBr6 and Cs2SnI6. Single phase structures formed across the entirety of both composition series with no evidence of long-range anion ordering observed by diffraction. A distortion of the cubic A2BX6 structure was identified in which the spacing of the BX6 octahedra changes to accommodate the A site cation without reduction of overall symmetry. Optical band gap values varied with anion composition between 4.89 eV in Cs2SnCl6 to 1.35 eV in Cs2SnI6 but proved highly nonlinear with changes in composition. In mixed halide compounds, it was found that lower energy optical transitions appeared that were not present in the pure halide compounds, and this was attributed to lowering of the local symmetry within the tin halide octahedra. The electronic structure was characterized by photoemission spectroscopy, and Raman spectroscopy revealed vibrational modes in the mixed halide compounds that could be assigned to particular mixed halide octahedra. This analysis was used to determine the distribution of octahedra types in mixed anion compounds, which was found to be consistent with a near-random distribution of halide anions throughout the structure, although some deviations from random halide distribution were noted in mixed iodide-bromide compounds, where the larger iodide anions preferentially adopted trans configurations

Spatial Electron-hole Separation in a One Dimensional Hybrid Organic-Inorganic Lead Iodide.

The increasing efficiency of the inorganic-organic hybrid halides has revolutionised photovoltaic research. Despite this rapid progress, the significant issues of poor stability and toxicity have yet to be suitably overcome. In this article, we use Density Functional Theory to examine (Pb2I6) · (H2DPNDI) · (H2O) · (NMP), an alternative lead-based hybrid inorganic-organic solar absorber based on a photoactive organic cation. Our results demonstrate that optical properties suitable for photovoltaic applications, in addition to spatial electron-hole separation, are possible but efficient charge transport may be a limiting factor

Groundwater Availability of the Barton Springs Segment of the Edwards Aquifer, Texas: Numerical Simulations Through 2050

A two-dimensional, numerical groundwater-flow model was developed for the Barton Springs segment of the Edwards aquifer to evaluate groundwater availability and predict water levels and spring flow in response to increased pumpage and droughts during the period 2001 through 2050. A steady-state model was developed on the basis of average recharge for a 20-year period (1979 through 1998) and pumpage values for 1989. Transient simulations were conducted using monthly recharge and pumping data for a 10-year period (1989 through 1998) that includes periods of low and high water levels. Values of hydraulic conductivity were estimated by calibrating the steady-state model using trial and error and automated inverse methods. Good agreement was found between measured and simulated flow at Barton Springs (root mean square error [RMS error, average of squared differences in measured and simulated discharges] 12 cfs), between measured and simulated water levels at different times, and between measured and simulated water levels in many of the monitoring wells. To assess the impact of future pumpage and potential future droughts on groundwater availability, transient simulations were conducted using extrapolated pumpage for 10-year periods (2001 through 2050) and average recharge for a 3-year period and recharge from the 1950s drought for the remaining 7 years. Results of these simulations were compared with those using average recharge and future pumpage. Predicted water-level declines in response to future pumpage under average recharge conditions are small (270 ft). Simulated spring discharge in response to future pumpage under average recharge decreased proportionally to future pumpage (2 cfs per decade), whereas spring discharge decreased to 0 cfs in response to future pumpage under drought-of-record conditions. Management of water resources under potential future drought conditions should consider enhanced recharge and conservation measures.Bureau of Economic Geolog