Increased temperature in urban ground as source of sustainable energy

This paper is part of the Proceedings of the 10th International Conference on Urban Regeneration and Sustainability (Sustainable City 2015). http://www.witconferences.comDensely urbanized areas are characterized by special microclimatic conditions with typically elevated temperatures in comparison with the rural surrounding. This phenomenon is known as the urban heat island (UHI) effect, but not restricted exclusively to the atmosphere. We also find significant warming of the urban subsurface and shallow groundwater bodies. Here, main sources of heat are elevated ground surface temperatures, direct thermal exploitation of aquifers and heat losses from buildings and other infrastructure. By measuring the shallow groundwater temperature in several European cities, we identify that heat sources and associated transport processes interact at multiple spatial and temporal scales. The intensity of a subsurface UHI can reach the values of above 4 K in city centres with hotspots featuring temperatures up to +20°C. In comparison with atmospheric UHIs, subsurface UHIs represent long-term accumulations of heat in a relatively sluggish environment. This potentially impairs urban groundwater quality and permanently influences subsurface ecosystems. From another point of view, however, these thermal anomalies can also be seen as hidden large-scale batteries that constitute a source of shallow geothermal energy. Based on our measurements, data surveys and estimated physical ground properties, it is possible to estimate the theoretical geothermal potential of the urban groundwater bodies beneath the studied cities. For instance, by decreasing the elevated temperature of the shallow aquifer in Cologne, Germany, by only 2 K, the obtained energy could supply the space-heating demand of the entire city for at least 2.5 years. In the city of Karlsruhe, it is estimated that about 30% of annual heating demand could be sustainably supplied by tapping the anthropogenic heat loss in the urban aquifer. These results reveal the attractive potential of heated urban ground as energy reservoir and storage, which is in place at many places worldwide but so far not integrated in any city energy plans.This work was supported by the Swiss National Science Foundation (SNSF) under grant number 200021L 144288, and the German Research Foundation (DFG), under grant number BL 1015/4-1

Isostaticity and the solidification of semiflexible polymer melts

Using molecular dynamics simulations of a tangent-soft-sphere bead-spring polymer model, we examine the degree to which semiflexible polymer melts solidify at isostaticity. Flexible and stiff chains crystallize when they are isostatic as defined by appropriate degree-of-freedom-counting arguments. Semiflexible chains also solidify when isostatic if a generalized isostaticity criterion that accounts for the slow freezing out of configurational freedom as chain stiffness increases is employed. The dependence of the average coordination number at solidification $Z(T_s)$ on chains' characteristic ratio $C_\infty$ has the same functional form [$Z \simeq a - b\ln(C_\infty)$] as the dependence of the average coordination number at jamming $Z(\phi_J)$ on $C_\infty$ in athermal systems, suggesting that jamming-related phenomena play a significant role in thermal polymer solidification

Investigation and Prosecution of Sexual Assault, Domestic Violence, and Stalking

This project examined sexual assault, domestic violence, and stalking cases reported to the Alaska State Troopers. More specifically, we examined all sexual assault and sexual abuse of minor incidents reported to Alaska State Troopers in 2003 and 2004, all assaults in domestic violence incidents reported to Alaska State Troopers in 2004, and all stalking incidents reported to Alaska State Troopers from 1994 to 2005. In addition, we examined whether cases were referred to the Alaska Department of Law for prosecution, were accepted for prosecution, and resulted in a conviction. This report provides a thorough overview of key characteristics on reports, suspects, victims, incidents, witnesses, and legal resolutions. This report also examines the predictors of legal resolutions. Finally, this report examines whether rural cases are less likely to have successful legal resolutions. Results clearly show that what Alaska State Troopers do when investigating reported offenses can increase rates of referral, acceptance, and conviction. In addition, we found no evidence of under-enforcement in rural areas. Contrary to allegations that the provision of criminal justice services is diminished in rural areas, we found that geographic isolation does not hinder case processing. These results are important for other rural jurisdictions. Most importantly, we found that cases first reported to local first responders had better legal resolutions. This finding suggests that the resources provided by these first responders (i.e., reduced response time and enhanced investigation) increase the rates of prosecutions and convictions. This finding is important not just in Alaska, but in other jurisdictions where official responders are not immediately available.National Institute of Justice, Office of Justice Programs, U.S. Department of Justice. Grant No. 2005-WG-BX-0011I. Index of Tables and Figures / II. Acknowledgments / III. Executive Summary / IV. Goals and Background for this Study / V. State of Alaska / VI. Sexual Assault / VII. Domestic Violence / VIII. Stalking / IX. References / X. Appendice

Universal R-C crossover in current-voltage characteristics for unshunted array of overdamped Nb-AlO_x-Nb Josephson junctions

We report on some unusual behavior of the measured current-voltage characteristics (CVC) in artificially prepared two-dimensional unshunted array of overdamped Nb-AlO_x-Nb Josephson junctions. The obtained nonlinear CVC are found to exhibit a pronounced (and practically temperature independent) crossover at some current I_{cr}=\left(\frac{1}{2\beta_C}-1\right)I_C from a resistance R dominated state with V_R=R\sqrt{I^2-I_C^2} below I_{cr} to a capacitance C dominated state with V_C=\sqrt{\frac{\hbar}{4eC}} \sqrt{I-I_C} above I_{cr}. The origin of the observed behavior is discussed within a single-plaquette approximation assuming the conventional RSJ model with a finite capacitance and the Ambegaokar-Baratoff relation for the critical current of the single junction