The influence of persistence and variability on the required solar radiation record length

An analysis was made of 17 years of total daily global solar radiation measurements made at St. Paul, Minnesota, a station located in the heart of North America and representative of a continental climate. The analysis was made with the objective of determining the degree of persistence in the solar radiation data and demonstrating the effect of persistence on the statistical analysis of these data.It is concluded that persistence varies through the year and that the characteristic time between independent observations ranges from slightly more than one day to just over three days. Two methods of estimating persistence revealed that some persistence results from daily serial correlation in the solar radiation data and that some persistence is due to interannual variability of monthly mean daily solar radiation.     

The potential risks of liquefied natural gas

Imported liquefied natural gas can provide needed supplements to diminishing domestic gas supplies as well as being a convenient means for the storage and transportation of natural gas. LNG vessels and facilities are, however, costly and present the risk of potentially large accidents. We describe these risks and the impacts of LNG operations, summarize the safety issues, and make several policy recommendations for the responsible use of this premium fossil fuel.     

The use of functionalized polymers as photosensitizers in an energy storage reaction

Insoluble polymer bound photosensitizers, useful for the conversion of norbornadiene (1) to quadricyclene (2), have been synthesized. An acetophenone analogue was produced by Friedel-Crafts acylation of polystyrene resin while treatment of chloromethylated resin with salicyladehyde and triethylamine produced an anlogue of benzyloxybenzaldehyde. Reaction of lithio---polystyrene resin with methyl 4-(N,N-dimethylamino)benzoate gave a ketone equivalent to 4-(N,N-dimethylamino)benzophenone (3). Quantum yields for the conversion of 1 and 2 using the polymer bound sensitizers were generally comparable to, but slightly lower than, the analogous compound in homogeneous solution. The quantum yield of polymer bound 3 was less solvent dependent than that of the homogeneous counterpart. The advantages of isolating the photosensitizer to the photochemical reactor stage of a photochemical solar energy storage device are discussed. Efficient sensitization by polymer bound photosensitizers demonstrates the feasibility of this approach.     

Periodic Inclusion—Matrix Microstructures with Constant Field Inclusions

We find a class of special microstructures consisting of a periodic array of inclusions, with the special property that constant magnetization (or eigenstrain) of the inclusion implies constant magnetic field (or strain) in the inclusion. The resulting inclusions, which we term E-inclusions, have the same property in a finite periodic domain as ellipsoids have in infinite space. The E-inclusions are found by mapping the magnetostatic or elasticity equations to a constrained minimization problem known as a free-boundary obstacle problem. By solving this minimization problem, we can construct families of E-inclusions with any prescribed volume fraction between zero and one. In two dimensions, our results coincide with the microstructures first introduced by Vigdergauz,[1,2] while in three dimensions, we introduce a numerical method to calculate E-inclusions. E-inclusions extend the important role of ellipsoids in calculations concerning phase transformations and composite materials. This article is based on a presentation made in the symposium entitled "Phase Transformations in Magnetic Materials", which occurred during TMS Annual Meeting, March 12–16, 2006, in San Antonio, TX, under the auspices of the Joint TMS-MPMD and ASMT-MSCTS Phase Transformations Committee.     

Heterogeneity in the families of sons of alcoholics: The impact of familial vulnerability type on offspring characteristics.

In 2 samples of sons of alcoholics (family history positive for alcoholism; FHP: N?=?74 & N?=?72), cluster analyses identified 3 subtypes of familial vulnerability: 1 with low levels of familial psychopathology (FHP-LP) and moderate levels of familial alcoholism; a 2nd with high levels of familial antisocial personality (FHP-ASP), violence, and alcoholism; and a 3rd with high levels of familial depression (FHP-DEP), mania, anxiety disorder, and alcoholism. Compared with family history negative (FHN) participants (N?=?106), FHP offspring had higher levels of alcohol problems. FHP-ASP offspring had elevated levels of antisocial traits and negative affect. Compared with FHN participants, FHP-DEP offspring elevated levels of antisocial traits, hypomania, and experience seeking. FHP-LP offspring had moderate levels of antisocial traits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Computational fluid dynamic analysis of core bypass flow phenomena in a prismatic VHTR

The core bypass flow in a prismatic very high temperature reactor (VHTR) is an important design consideration and can have considerable impact on the condition of reactor core internals including fuels. The interstitial gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The occurrence of hot spots in the core and lower plenum and hot streaking in the lower plenum (regions of very hot gas flow) are affected by bypass flow.     

Comparison of natural convection flows under VHTR type conditions modeled by both the conservation and incompressible forms of the Navier-Stokes equations

This paper illustrates a comparative study to analyze the physical differences between numerical simulations obtained with both the conservation and incompressible forms of the Navier-Stokes equations for natural convection flows in simple geometries. The purpose of this study is to quantify how the incompressible flow assumption (which is based upon constant density advection, divergence-free flow, and the Boussinesq gravitational body force approximation) differs from the conservation form (which only assumes that the fluid is a continuum) when solving flows driven by gravity acting upon density variations resulting from local temperature gradients. Driving this study is the common use of the incompressible flow assumption in fluid flow simulations for nuclear power applications in natural convection flows subjected to a high heat flux (large temperature differences). A series of simulations were conducted on two-dimensional, differentially heated rectangular geometries and modeled with both hydrodynamic formulations. From these simulations, the selected characterization parameters of maximum Nusselt number, average Nusselt number, and normalized pressure reduction were calculated. Comparisons of these parameters were made with available benchmark solutions for air with the ideal gas assumption at both low and high heat fluxes. Additionally, we generated specific force quantities and velocity and temperature distributions to provide a basis for further analysis. The simulations and analysis were then extended to include helium at the Very High Temperature gas-cooled Reactor (VHTR) normal operating conditions. Our results show that the consequences of incorporating the incompressible flow assumption in high heat flux situations may lead to unrepresentative results. The results question the use of the incompressible flow assumption for simulating fluid flow in an operating nuclear reactor, where large temperature variations are present.     

A theory of field-ion imaging: I. A quasi-classical site-current formula

A quasi-classical formulation of field-ion imaging theory is defined and discussed. Concepts and terminology are defined, and a formula is established for the ion current generated above a single surface site.