Dynamic precession damper for spin stabilized vehicles Patent

Dynamic precession damping of spin-stabilized vehicles by using rate gyroscope and angular acceleromete

Attitude orientation of spin-stabilized space vehicles Patent

Attitude orientation control of spin stabilized final stage space vehicles, using horizon scanner

Gait Lab Validation of Direct Force Measurement in a Transfemoral Prosthesis

Technological advancements in prosthetic limbs for individuals with lower-limb amputation have resulted in a number of microprocessor-controlled knee and ankle systems in the commercial market. Such systems have the potential to provide enhanced and expanded functionality by being able to actively react to changes in terrain or gait. However, the extent to which this potential is realized in practice remains an open question. There are multiple methods to evaluate the performance of the amputee limb system. The conventional approach to gait analysis involves motion capture cameras and floor-embedded force transducers that are limited to laboratory settings that fail to adequately simulate real-world locomotor function. Alternatively, the approach of direct force measurement provides gait assessments via sensors directly integrated within the prosthetic limb system. This method, when combined with wireless data transmission, enables continuous measurement of prosthetic-limb performance in field settings unsuitable for conventional gait analysis. The objectives of this effort are to compare the prosthetic-limb kinetics as measured by limb-integrated transducers to that obtained via conventional gait analysis and ultimately validate direct force measurement as a tool for field evaluation of prosthetic-limb performance. The work to be presented will discuss the technical details of each system and the progress to date in the collection and analysis of gait data from a single patient with unilateral transfemoral amputation

The Effects Of Thyroxine On Deoxyribonucleic Acid Content In The Brain Of Rana Clamitans Tadpoles

The metamorphic changes transforming the tissues of the tadpole into those of the mature frog are known to be under the control of thyroid hormone, that is, they fail to occur if the hormone is absent. However, it is becoming increasingly clear that control does not mean the determination of the specific character of the ensuing changes, but refers merely to the reactivated and further sustenance of different chains of morphogenetic events temporarily arrested in the larval stage, then continuing in each tissue reacting according to its own characteristics (Weiss and Rossetti, 1951). The importance of the thyroid gland as a controlling factor in metamorphosis is to be credited to Gudernatsch (1912) who fed horse thyroid gland to amphibian larvae and found that they showed an increase in metamorphosis. A great amount of work has been done along the line of experimental hyperthyroidism in the amphibian. The work of Allen (1916) and Hoskins (1917) on the removal of the thyroid gland in amphibian larvae clearly indicates that this gland is normally indispensable to metamorphosis in these forms. In more recent years investigators have been concerned with direct action of thyroid hormone on various reacting systems (Kaltenbach, 1953a). Thyroid hormone has been shown to influence a variety of systems in the amphibian, including the nervous system. The nervous system responds to thyroid hormone by an increase in cell number (Kollros and Race, 1960; Race, 1961). Thyroxine also influences cell size (Weiss and Rossetti, 1951; Pesetsky and Kollros, 1956; Reynolds, 1963). Weiss and Rossetti (1951) reported a marked spurt in brain growth in Rana pipiens during metamorphosis, which is accompanied by intensified activity during normal metamorphic climax. A similar increase in mitotic activity has been reported by Martin (1962) in studies of normal development of the cerebellum in Rana pipiens, in young tadpoles immersed in high concentrations of thyroxine, and also by Reynolds (1966) in studies of the lumbo-sacral spinal cord of Rana pipiens larvae. Various hormones, depending on their nature and degree of activity in the organism, exert a certain effect on the metabolism of nucleic acids. Mandel (1951) reported that after the injection of thyroxine (1 mg. per day) into rats, DMA content increased from 22 to 32% in the kidney. Similar increases in spleen ranged from 35 to 60% (Handel, 1952). A single injection of thyroxine into male mice has the effect of raising the proportion of DNA and proteins relative to MIA in the liver after 48 hours (Baxi, 1951)

Parallelization of the Advancing Front Local Reconnection Mesh Generation Software Using a Pseudo-Constrained Parallel Data Refinement Method

Preliminary results of a long-term project entailing the parallelization of an industrial strength sequential mesh generator, called Advancing Front Local Reconnection (AFLR), are presented. AFLR has been under development for the last 25 years at the NSF/ERC center at Mississippi State University. The parallel procedure that is presented is called Pseudo-constrained (PsC) Parallel Data Refinement (PDR) and consists of the following steps: (i) use an octree data-decomposition scheme to divide the original geometry into subdomains (octree leaves), (ii) refine each subdomain with the proper adjustments of its neighbors using the given refinement code, and (iii) combine all subdomain data into a single, conforming mesh. Parallelism was achieved by implementing Pseudo-constrained Parallel Data Refinement AFLR (PsC.AFLR) on top of a runtime system called Parallel Runtime Environment for Multi-computer Applications (PREMA). During run time, the PsC.AFLR method exposes data decomposition information (number of subdomains waiting to be refined) to the underlying runtime system. In turn, this system facilitates work-load balancing and guides the program’s execution towards the most efficient utilization of hardware resources. Preliminary results, on the mesh refinement operation, show that the end-user productivity (measured in terms of elements refined per second) increases as the number of cores in use are increased. When using approximately 16 cores, PsC.AFLR outperforms the serial AFLR code by about 11 times. PsC.AFLR also maintains its stability by generating meshes of comparable quality. Although it offers good end-user productivity, PsC.AFLR suffers in its capability to generate meshes with the same level of density or quality as that of the serial AFLR software due to the constraints set by subdomain boundaries that are required to successfully execute AFLR. These constraints demonstrate that it is not ideal to use AFLR in a black box manner when parallelizing the software. Its source code must be modified to a non-trivial extent if one wishes to remove these constraints and maximize the end-user productivity and potential scalability

Using Paired Comparison Matrices to Estimate Parameters of the Partial Credit Rasch Measurement Model for Rater-Mediated Assessments

The purpose of this paper is to describe a technique for estimating the parameters of a Rasch model that accommodates ordered categories and rater severity. The technique builds on the conditional pairwise algorithm described by Choppin (1968, 1985) and represents an extension of a conditional algorithm described by Garner and Engelhard (2000, 2002) in which parameters appear as the eigenvector of a matrix derived from paired comparisons. The algorithm is used successfully to recover parameters from a simulated data set. No one has previously described such an extension of the pairwise algorithm to a Rasch model that includes both ordered categories and rater effects. The paired comparisons technique has importance for several reasons: it relies on the separability of parameters that is true only for the Rasch measurement model; it works in the presence of missing data; it makes transparent the connectivity needed for parameter estimation; and it is very simple. The technique also shares the mathematical framework of a very popular technique in the social sciences called the Analytic Hierarchy Process (Saaty, 1996)

Jet shoes

Jet shoes for space locomotio