Space reactor shielding fabrication

The fabrication of space reactor neutron shielding by a melting and casting process utilizing lithium hydride is described. The first neutron shield fabricated is a large pancake shape 86 inches in diameter, containing about 1700 pounds of lithium hydride. This shield, fabricated by the unique melting and casting process, is the largest lithium hydride shield ever built

Cold gas in the inner regions of intermediate redshift clusters

Determining gas content and star formation rate has known remarkable progress in field galaxies, but has been much less investigated in galaxies inside clusters. We present the first CO observations of luminous infrared galaxies (LIRGs) inside the virial radii of two intermediate redshift clusters, CL1416+4446 (z=0.397) and CL0926+1242 (z=0.489). We detect three galaxies at high significance (5 to 10 sigma), and provide robust estimates of their CO luminosities, L'CO. In order to put our results into a general context, we revisit the relation between cold and hot gas and stellar mass in nearby field and cluster galaxies. We find evidence that at fixed LIR (or fixed stellar mass), the frequency of high L'CO galaxies is lower in clusters than in the field, suggesting environmental depletion of the reservoir of cold gas. The level of star formation activity in a galaxy is primarily linked to the amount of cold gas, rather than to the galaxy mass or the lookback time. In clusters, just as in the field, the conversion between gas and stars seems universal. The relation between LIR and L'CO for distant cluster galaxies extends the relation of nearby galaxies to higher IR luminosities. Nevertheless, the intermediate redshift galaxies fall well within the dispersion of the trend defined by local systems. Considering that L'CO is generally derived from the CO(1-0) line and sensitive to the vast majority of the molecular gas in the cold interstellar medium of galaxies, but less to the part which will actually be used to form stars, we suggest that molecular gas can be stripped before the star formation rate is affected. Combining the sample of Geach et al. (2009, 2011) and ours, we find evidence for a decrease in CO towards the cluster centers. This is the first hint of an environmental impact on cold gas at intermediate redshift.Comment: Accepted for publication in Astronomy and Astrophysic

Singing and vocal development

Musical development begins pre-birth through the fetal experiences of the melody-like contouring of our mother’s voice. These earliest experiences form the foundation for subsequent musical, vocal, and linguistic behavior. Ongoing interactions between our individual neuropsychobiological development and the sounds and expectations of the maternal sociocultural environment continue to shape the development of vocal skills, including singing, throughout childhood and into adolescence. By puberty, self-identity (whether tending toward the positive or negative) in relation to the art and expectations of singing in different contexts is firmly established. If exposed to an appropriately nurturing environment, considerable singing skills are normally evidenced. The experience of negative comments during childhood, particularly from adults such as parents and teachers, can have a detrimental impact on singing behaviors and the realization of musical potential. Throughout these formative years from birth onward, individual singing development is usually incremental and positive, but can be inhibited by sociocultural factors

Neuromuscular control of wingbeat kinematics in Anna's hummingbirds (Calypte anna)

Hummingbirds can maintain the highest wingbeat frequencies of any flying vertebrate – a feat accomplished by the large pectoral muscles that power the wing strokes. An unusual feature of these muscles is that they are activated by one or a few spikes per cycle as revealed by electromyogram recordings (EMGs). The relatively simple nature of this activation pattern provides an opportunity to understand how motor units are recruited to modulate limb kinematics. Hummingbirds made to fly in low-density air responded by moderately increasing wingbeat frequency and substantially increasing the wing stroke amplitude as compared with flight in normal air. There was little change in the number of spikes per EMG burst in the pectoralis major muscle between flight in normal and low-density heliox (mean=1.4 spikes cycle^(–1)). However the spike amplitude, which we take to be an indication of the number of active motor units, increased in concert with the wing stroke amplitude, 1.7 times the value in air. We also challenged the hummingbirds using transient load lifting to elicit maximum burst performance. During maximum load lifting, both wing stroke amplitude and wingbeat frequency increased substantially above those values during hovering flight. The number of spikes per EMG burst increased to a mean of 3.3 per cycle, and the maximum spike amplitude increased to approximately 1.6 times those values during flight in heliox. These results suggest that hummingbirds recruit additional motor units (spatial recruitment) to regulate wing stroke amplitude but that temporal recruitment is also required to maintain maximum stroke amplitude at the highest wingbeat frequencies

The spacecraft control laboratory experiment optical attitude measurement system

A stereo camera tracking system was developed to provide a near real-time measure of the position and attitude of the Spacecraft COntrol Laboratory Experiment (SCOLE). The SCOLE is a mockup of the shuttle-like vehicle with an attached flexible mast and (simulated) antenna, and was designed to provide a laboratory environment for the verification and testing of control laws for large flexible spacecraft. Actuators and sensors located on the shuttle and antenna sense the states of the spacecraft and allow the position and attitude to be controlled. The stereo camera tracking system which was developed consists of two position sensitive detector cameras which sense the locations of small infrared LEDs attached to the surface of the shuttle. Information on shuttle position and attitude is provided in six degrees-of-freedom. The design of this optical system, calibration, and tracking algorithm are described. The performance of the system is evaluated for yaw only

President\u27s Notes

It has been interesting to note, in these troubled times, the reemergence of history as a topical theme in Op Ed pieces and articles in any number of newspapers and journals. Before coming to the Naval War College, I had heard some criticism of the curriculum\u27s emphasis on the lessons of history to the neglect of preparation for the present

CLIMATE ACTION PLANS - FACT OR FICTION? EVIDENCE FROM MARYLAND

On a sweltering summer day in 1988, NASA scientist James Hansen sounded the alarm, in a congressional hearing, that human activity was changing our climate and without action, the world would face grave danger. Since that time, the United States government has ignored international climate policy efforts and failed multiple times to enact federal guidelines to address this serious problem. In the last decade, state governments have begun to formulate their own climate policy in an effort called Climate Action Planning. Climate action plans seek aggressive reductions and form the backbone of most statewide environmental policies but they often suffer from a lack of scientific analysis, unrealistic expectations, little funding, non-existent implementation strategies, and have no enforcement mechanisms. While plans have proliferated across the nation, little has been done to examine closely the ability of the policies to achieve climate change mitigation goals through enumerated strategies. This thesis fills part of the research void by examining all of the built environment emissions reduction strategies specified in the Maryland CAP. The analysis proceeds by developing multiple models calibrated with local empirical data. The results of this analysis show that Maryland, even with a successful implementation of its CAP will not meet its carbon mitigation targets. Further analysis reveals that a full state, national, and global implementation of similar carbon reduction targets would not alter the trajectory of climate change. To address climate change adequately, Maryland should take a three-prong approach. First, strengthen the mitigation strategies that show the greatest potential to reduce CO2 while abandoning strategies that do not. Second, extend the current set of strategies to include the low hanging and quickly implementable mitigation `fruit'. Third, in the face of serious and inevitable climate change, begin to adapt the built environment for better resiliency to more extreme conditions. The thesis concludes with a call to action for urban planners to address ambiguities that relate to the climate change and the build environment. The timing is "ripe" for planners to take the lead in what will certainly become the next great wave of planning

REVIEW OF ANIMAL REPELLENTS

A review of the literature on this subject reveals there is considerable confusion regarding the meaning of the word repellent as it relates to animal control. Some people make a liberal interpretation and include any material or device that will alter the pattern of activity of an animal through response to sight, sound, taste, odor, or touch. Although such an interpretation may be valid, for this paper I would like to confine my discussion to chemical repellents -- materials that, when applied to seeds, plants, or other materials being damaged by animals, will reduce depredation through taste, odor, or possibly irritation. The idea of using distasteful or foul-smelling materials to prevent losses from animals is not new and probably goes back to antiquity. Since World War II, however, increased importance has been placed on this method of control , and research has been stepped up in recent years in an effort to develop more effective and useful materials to reduce losses by rodents, deer, rabbits, birds, and other animals that damage orchards, agricultural crops, and forest seeds and seedlings, and by commensal rats and mice that damage food packages, textiles, and other materials of economic importance. As many of you know, the Denver Center has played an important part in this work. Much of this research has been made possible through continuing grants from the U. S. Army. The Army\u27s Electronics Command recently increased its support to speed up research on protecting cable from rodents because of damage being experienced in Vietnam. The search for chemical repellents also gained ground as a result of the recommendations of the Leopold Report, which stated, We further recommend that the [Bureau\u27s] research program shift some of its attention from methods of killing animals to ways of preventing depredations by repelling, excluding, or frightening animals. To accomplish this, major changes have been made in our chemical screening and development program, and the outlook for improved contact repellents looks promising (Kverno et al., 1965)

Quantum Fourier transform revisited

The fast Fourier transform (FFT) is one of the most successful numerical algorithms of the 20th century and has found numerous applications in many branches of computational science and engineering. The FFT algorithm can be derived from a particular matrix decomposition of the discrete Fourier transform (DFT) matrix. In this paper, we show that the quantum Fourier transform (QFT) can be derived by further decomposing the diagonal factors of the FFT matrix decomposition into products of matrices with Kronecker product structure. We analyze the implication of this Kronecker product structure on the discrete Fourier transform of rank-1 tensors on a classical computer. We also explain why such a structure can take advantage of an important quantum computer feature that enables the QFT algorithm to attain an exponential speedup on a quantum computer over the FFT algorithm on a classical computer. Further, the connection between the matrix decomposition of the DFT matrix and a quantum circuit is made. We also discuss a natural extension of a radix-2 QFT decomposition to a radix-d QFT decomposition. No prior knowledge of quantum computing is required to understand what is presented in this paper. Yet, we believe this paper may help readers to gain some rudimentary understanding of the nature of quantum computing from a matrix computation point of view