Magnetic Gimbal Proof-of-Concept Hardware performance results

The Magnetic Gimbal Proof-of-Concept Hardware activities, accomplishments, and test results are discussed. The Magnetic Gimbal Fabrication and Test (MGFT) program addressed the feasibility of using a magnetic gimbal to isolate an Electro-Optical (EO) sensor from the severe angular vibrations induced during the firing of divert and attitude control system (ACS) thrusters during space flight. The MGFT effort was performed in parallel with the fabrication and testing of a mechanically gimballed, flex pivot based isolation system by the Hughes Aircraft Missile Systems Group. Both servo systems supported identical EO sensor assembly mockups to facilitate direct comparison of performance. The results obtained from the MGFT effort indicate that the magnetic gimbal exhibits the ability to provide significant performance advantages over alternative mechanically gimballed techniques

Multiple degree-of-freedom force and moment measurement for static propulsion testing using magnetic suspension technology

Innovative Information Systems (IIS), Inc. is in the process of designing and fabricating a high bandwidth force and moment measuring device (i.e. the Magnetic Thruster Test Stand). This device will use active magnetic suspension to allow direct measurements of the forces and torques generated by the rocket engines of the missile under test. The principle of operation of the Magnetic Thruster Test Stand (MTTS) is based on the ability to perform very precise, high bandwidth force and position measurements on an object suspended in a magnetic field. This ability exists due to the fact that the digital servo control mechanism that performs the magnetic suspension uses high bandwidth (10 kHz) position data (via an eddy-current proximity sensor) to determine the amount of force required to maintain stable suspension at a particular point. This force is converted into required electromagnet coil current, which is then output to a current amplifier driving the coils. A discussion of how the coil current and magnetic gap distance (the distance between the electromagnet and the object being suspended) is used to determine the forces being applied from the suspended assembly is presented

Nucleon-nucleon scattering using dispersion relations

Imperial Users onl

Towards an analysis of academic weblogs

This paper analyses both the communicative purposes and formal linguistic features of academic weblogs. An initial analysis of 496 weblogs in use within tertiary level institutions was reduced to an in-depth analysis of 39 academic weblogs (a corpus of 16 million words). The objective was to see how much variation there might be between traditional academic genres and academic weblogs. The initial hypothesis is that academic weblogs are far less formal and would favour greater use of lexico-grammatical realisations belonging to the interpersonal function of language. In order to quantify this possible variation between traditional academic genres and academic weblogs, some well-known linguistic features which have been considered to be typical of academic discourse such as the agentless passive and nominalisations were investigated

Charisma and Spirituality in the Early Church: A Study of Messalianism and Pseudo-Macarius

The thesis is an investigation into the concept of Charisma and Spirituality in the Early Church with particular emphasis upon the writings of Ps-Macarius, and of a group of ascetics known as the Messalians, evident in the late fourth / early fifth centuries. The Macarian writings are examined to see what they reveal about the experiential pneumatic theology of the Early Church, the relationship between Syrian and Hellenic traditions of Christian Rhetoric, and the relationship between Ps-Macarius and the Cappadocian Circle. The Macarian corpus as a whole is examined to assess its rhetorical influences and style. The rhetoric of the Macarian corpus is seen to illustrate a high degree of sophistication. This study also gives definition to two terms that have become imprecise and diverse in their use: 'enkrateia' (self-control), and `Syrian Christianity'. By isolating the characteristics of enkratefa the definitive stages of an encratic lifestyle are identified. The breaking down of the term into enkrateia, radical enkrateta and exclusive enkrateta enables a much clearer discussion to take place as to the nature of the encratic theology of a group or individual. The final element of this study is a consideration of the distinct Macarian imagery that is evident within the corpus. Two images are considered in detail, the 'flight of the soul' and 'sober intoxication'. Overall this study shows the variety of influences upon Ps-Macarius, and the uniqueness of his expression. The influences upon Ps-Macarius include a context of endemic Syrian spirituality, a radical encratic lifestyle, a Hellenic rhetorical training, and a distinct interpretation of Platonic and Neo- Platonic images, coupled to the wider Judaic / Mesopotamian influences of his Church. It is shown that Ps-Macarius represents an individual voice that is distinct and recognisable amongst the Fathers of the Church

Cardiovascular responses to diving in the turtle, Pseudemys scripta

The cardiovascular responses to diving in the freshwater turtle, Pseudemys scripta, were determined by using the classical techniques of electrocardiography, impedance pneumography and direct blood pressure recording. The radioactive microsphere method was used to measure cardiac output and regional blood flows as well as to quantitate the intracardiac shunting of blood;Following a forced dive (with the animal being firmly attached to an adjustable diving platform) the heart rate gradually decreased by as much as 98%. Voluntarily diving animals, however, usually showed an immediate bradycardia of about 28%. A heart rate reduction similar to that obtained in voluntarily diving animals was occasionally observed during apnea in aerial turtles;Mean systemic and pulmonary arterial blood pressures did not change during diving, but pulse pressures increased about 2-fold. Central venous pressure remained constant;Total heart output was reduced by one-half in forcibly submerged animals. Since the pulmonary and systemic circuits are in parallel rather than in series, blood flow through the 2 systems need not be equal. In the submerged turtles, blood flow to the lungs decreased by 70%, while systemic flow decreased 39%. Stroke volume increased by 146% to the 2 systemic arteries, while increasing only 19% to the pulmonary trunk. Most of the parameters measured showed a large variation between animals;Pulmonary vascular resistance was elevated 235% after forced submergence while the systemic impedance increased 62%. The impedance of the 2 circuits was similar in aerial animals;Above water, animals showed a 25% net right-to-left intracardiac shunt (25% of the right atrial blood being ejected directly into the systemic arches) and this increased to 60% in submerged animals. Therefore, in relative terms, blood flow is being shifted away from the lungs and towards the systemic tissues during a forced dive;Microsphere data indicated that right-to-left shunted blood is directed primarily to the left aorta in turtles. Furthermore, the right atrial blood which did enter the brachiocephalic artery was, in large measure, kept away from the carotid arteries. Since the shunted and unshunted blood which enter the systemic arteries remains separated, viscera received more of the shunted blood, whereas the kidneys and posterior skeletal muscles received less;The vasoconstriction which allows blood pressure to be well maintained during diving appears to be a selective process. During a forced dive, blood was primarily distributed to the brain (537% increase), heart and skeletal muscles. Flow was drastically reduced to most other tissues;Due to methodological considerations, blood flow data could not be obtained in voluntarily diving animals. However, in forcibly submerged turtles, there occurred a cardiovascular response similar to that which is known to occur in birds and mammals

The EPA\u27s Discretion to Regulate Acid Rain: A Discussion of the Requirements for Triggering Section 115 of the Clean Air Act

Acid rain does not respect political boundaries; the problem of acid rain has had a devastating effect on human health and the environment of the northeastern United States as well as the area across the Canadian border. Recognizing the implications of trans-boundary air pollution problems such as acid rain, Congress amended section 115 of the Clean Air Act to permit the Administrator of the Environmental Protection Agency to order the reduction of air pollution menaces emanating from the United States which affect foreign nations. New York v. Thomas is the first major case to interpret section 115 and it will have a major impact on the ability to combat international acid rain problems through the Clean Air Act. This note discusses issues which often arise in environmental litigation such as the difficulties in identifying sources and assessing responsibility, the problem of interpreting statutory language to decide how much discretion agency officials have to not pursue identified environmental hazards, and most importantly, under what circumstances notice and comment is required and when in the rulemaking process it must be given. This note shows that the court of appeals\u27 ruling on the notice and comment issue in this case has incorrectly permitted practically unlimited discretion to EPA administrators under section 115 of the Clean Air Act. The unfortunate impact of this ruling is that it allows EPA Administrators, when faced with identified international environmental hazards such as the acid rain problem affecting Canada and the northeastern United States, to ignore the situation indefinitely

The EPA\u27s Discretion to Regulate Acid Rain: A Discussion of the Requirements for Triggering Section 115 of the Clean Air Act

Acid rain does not respect political boundaries; the problem of acid rain has had a devastating effect on human health and the environment of the northeastern United States as well as the area across the Canadian border. Recognizing the implications of trans-boundary air pollution problems such as acid rain, Congress amended section 115 of the Clean Air Act to permit the Administrator of the Environmental Protection Agency to order the reduction of air pollution menaces emanating from the United States which affect foreign nations. New York v. Thomas is the first major case to interpret section 115 and it will have a major impact on the ability to combat international acid rain problems through the Clean Air Act. This note discusses issues which often arise in environmental litigation such as the difficulties in identifying sources and assessing responsibility, the problem of interpreting statutory language to decide how much discretion agency officials have to not pursue identified environmental hazards, and most importantly, under what circumstances notice and comment is required and when in the rulemaking process it must be given. This note shows that the court of appeals\u27 ruling on the notice and comment issue in this case has incorrectly permitted practically unlimited discretion to EPA administrators under section 115 of the Clean Air Act. The unfortunate impact of this ruling is that it allows EPA Administrators, when faced with identified international environmental hazards such as the acid rain problem affecting Canada and the northeastern United States, to ignore the situation indefinitely

Primary Teacher Education in Malawi: Insights Into Practice and Policy: Multi-Site Teacher Education Research Project (MUSTER), Country Report Three

Teaching/Communication/Extension/Profession,

APLF (C2orf13) is a novel human protein involved in the cellular response to chromosomal DNA strand breaks

Aprataxin and polynucleotide kinase (PNK) are DNA end processing factors that are recruited into the DNA single- and double-strand break repair machinery through phosphorylation-specific interactions with XRCC1 and XRCC4, respectively. These interactions are mediated through a divergent class of forkhead-associated (FHA) domain that binds to peptide sequences in XRCC1 and XRCC4 that are phosphorylated by casein kinase 2 (CK2). Here, we identify the product of the uncharacterized open reading frame C2orf13 as a novel member of this FHA domain family of proteins and we denote this protein APLF (aprataxin- and PNK-like factor). We show that APLF interacts with XRCC1 in vivo and in vitro in a manner that is stimulated by CK2. Yeast two-hybrid analyses suggest that APLF also interacts with the double-strand break repair proteins XRCC4 and XRCC5 (Ku86). We also show that endogenous and yellow fluorescent protein-tagged APLF accumulates at sites of H(2)O(2) or UVA laser-induced chromosomal DNA damage and that this is achieved through at least two mechanisms: one that requires the FHA domain-mediated interaction with XRCC1 and a second that is independent of XRCC1 but requires a novel type of zinc finger motif located at the C terminus of APLF. Finally, we demonstrate that APLF is phosphorylated in a DNA damage- and ATM-dependent manner and that the depletion of APLF from noncycling human SH-SY5Y neuroblastoma cells reduces rates of chromosomal DNA strand break repair following ionizing radiation. These data identify APLF as a novel component of the cellular response to DNA strand breaks in human cells