Is There Evidence that Legislative Ambition Matches Development? Evaluating the Factors Influencing Wind Energy Development

Resource /Energy Economics and Policy,

Comparing Climate-Change Mitigating Potentials of Alternative Synthetic Liquid Fuel Technologies Using Biomass and Coal

Presenter: Robert H. Williams, Senior Research Scientist, Princeton University, Princeton, NJ. 19 pages (includes color illustrations). Contains references

Low Temperature Performance of Bio-Derived/Chemical Additives in Warm Mix Asphalt

Corn and soy based bio-derived warm mix asphalt (WMA) additives are currently being developed. In the past, additives with similar properties have been shown to successfully reduce the mixing and compaction temperatures of asphalt by as much as 30°C. Isosorbide distillation bottoms (IDB), a WMA additive, is a co-product from the conversion of sorbitol to isosorbide, where sorbitol is derived by hydrogenating glucose from corn biomass. Past research utilizing IDB at several dosage rates showed there was improvement in low temperature binder performance using the bending beam rheometer (BBR) between dosage rates of 0.5% and 1.0% by weight of the binder. This research investigates whether low temperature improvement occurs with several new bio-derived material additives that have similar properties to materials used in past research, as well as compares their performance to two commercially available/bio-derived WMA additives from the forest products industry. In cold regions of the United States, the main observed distress in asphalt pavements is low temperature cracking. Characterization of binder performance at low temperature is possible with the use of the BBR. For asphalt mixtures, characterization is more challenging at low temperatures due to the response from the aggregate phase of a mixture. To examine low temperature performance of hot mix asphalt (HMA) and WMA, the semi-circular bend (SCB) test was used to characterize the fracture properties. SCB tests showed that additive choice was a statistically significant factor in fracture energy properties but not for stiffness and fracture toughness. All of the new additives were successfully used at reduced mixing and compaction temperatures and did not adversely impact low temperature mix fracture properties of WMA when compared against the control HMA. However, improvement of fracture energy was observed when comparing the epoxidized esterified fatty acid additive to the other five additives used in this work

Non-invasive neurosensory testing used to diagnose and confirm successful surgical management of lower extremity deep distal posterior compartment syndrome

<p>Abstract</p> <p>Background</p> <p>Chronic exertional compartment syndrome (CECS) is characterized by elevated pressures within a closed space of an extremity muscular compartment, causing pain and/or disability by impairing the neuromuscular function of the involved compartment. The diagnosis of CECS is primarily made on careful history and physical exam. The gold standard test to confirm the diagnosis of CECS is invasive intra-compartmental pressure measurements. Sensory nerve function is often diminished during symptomatic periods of CECS. Sensory nerve function can be documented with the use of non-painful, non-invasive neurosensory testing.</p> <p>Methods</p> <p>Non-painful neurosensory testing of the myelinated large sensory nerve fibers of the lower extremity were obtained with the Pressure Specified Sensory Device™ in a 25 year old male with history and invasive compartment pressures consistent with CECS both before and after running on a tread mill. After the patient's first operation to release the deep distal posterior compartment, the patient failed to improve. Repeat sensory testing revealed continued change in his function with exercise. He was returned to the operating room where a repeat procedure revealed that the deep posterior compartment was not completely released due to an unusual anatomic variant, and therefore complete release was accomplished.</p> <p>Results</p> <p>The patient's symptoms numbness in the plantar foot and pain in the distal calf improved after this procedure and his repeat sensory testing performed before and after running on the treadmill documented this improvement.</p> <p>Conclusion</p> <p>This case report illustrates the principal that non-invasive neurosensory testing can detect reversible changes in sensory nerve function after a provocative test and may be a helpful non-invasive technique to managing difficult cases of persistent lower extremity symptoms after failed decompressive fasciotomies for CECS. It can easily be performed before and after exercise and be repeated at multiple intervals without patient dissatisfaction. It is especially helpful when other traditional testing has failed.</p

Guided Neuronal Growth on Arrays of Biofunctionalized GaAs/InGaAs Semiconductor Microtubes

We demonstrate embedded growth of cortical mouse neurons in dense arrays of semiconductor microtubes. The microtubes, fabricated from a strained GaAs/InGaAs heterostructure, guide axon growth through them and enable electrical and optical probing of propagating action potentials. The coaxial nature of the microtubes -- similar to myelin -- is expected to enhance the signal transduction along the axon. We present a technique of suppressing arsenic toxicity and prove the success of this technique by overgrowing neuronal mouse cells.Comment: 3 pages, 4 figure

The Role of the Radial Orbit Instability in Dark Matter Halo Formation and Structure

For a decade, N-body simulations have revealed a nearly universal dark matter density profile, which appears to be robust to changes in the overall density of the universe and the underlying power spectrum. Despite its universality, the physical origin of this profile has not yet been well understood. Semi--analytic models by Barnes et al. (2005) have suggested that the density structure of dark matter halos is determined by the onset of the radial orbit instability (ROI). We have tested this hypothesis using N-body simulations of collapsing dark matter halos with a variety of initial conditions. For dynamically cold initial conditions, the resulting halo structures are triaxial in shape, due to the mild aspect of the instability. We examine how variations in initial velocity dispersion affect the onset of the instability, and find that an isotropic velocity dispersion can suppress the ROI entirely, while a purely radial dispersion does not. The quantity sigma^2/vc^2 is a criterion for instability, where regions with sigma^2/vc^2 <~1 become triaxial due to the ROI or other perturbations. We also find that the radial orbit instability sets a scale length at which the velocity dispersion changes rapidly from isotropic to radially anisotropic. This scale length is proportional to the radius at which the density profile changes shape, as is the case in the semi--analytic models; however, the coefficient of proportionality is different by a factor of ~2.5. We conclude that the radial orbit instability is likely to be a key physical mechanism responsible for the nearly universal profiles of simulated dark matter halos.Comment: 13 pages, 12 figures, accepted to Ap

Laboratory and Clinical Studies of Cardiac Transplantation

Cardiac transplantation was carried out on four patients at the Medical College of Virginia between May and October of 1968, in an effort to salvage them from the terminal stages of otherwise uncorrectable heart disease. Despite a strikingly good early recovery from operation in each case, three of the patients died of acute homograft rejection in one to three weeks; our second case is living and well, ten months after operation, and is at this writing the world\u27s third longest survivor. The world experience to June of 1969 includes about 130 cardiac transplants. Of the first 100 patients operated on over six months ago, 20 are surviving, and the majority of these have returned to a productive existence, demonstrating the feasibility of complete rehabilitation of at least some terminal patients after cardiac transplantation. The high mortality rate--significantly higher than was anticipated--has resulted from acute and chronic homograft rejection and from the equally difficult problem of infection. Certain lessons have been learned from our own experience and from the world experience with this procedure, and these will be reviewed in an attempt to establish the current status and future potential of cardiac transplantation

Use of Bioadvantaged Materials for Use in Bituminous Modification

AbstractHistorically, the use of “green” materials around the world has been limited due to their higher production costs when compared to petrochemical derived materials. However, due to the recent volatility and increasing price of petroleum derivatives, there is a growing demand for the use of environmentally friendly materials. One of the most commonly used materials for bitumen modification are poly(styrene-block-butadiene-block-styrene) (SBS) type polymers. Recently, Iowa State University Chemical Engineering Department was able to synthetize thermoplastic elastomers using acrylated epoxidized soybean oil (AESO), a bioadvantaged replacement of butadiene, and styrene with the use of controlled radical polymerization techniques. Initial rheological tests conducted on the bitumen-polymer blends have shown that the biopolymers improve the complex shear modulus of the bitumen to a similar and even greater extent as the commercially available SBS polymers