Encapsulation process sterilizes and preserves surgical instruments

Ethylene oxide is blended with an organic polymer to form a sterile material for encapsulating surgical instruments. The material does not bond to metal and can be easily removed when the instruments are needed

Process for preparing sterile solid propellants Patent

Using ethylene oxide in preparation of sterilized solid rocket propellants and encapsulating material

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

Optical processing for distributed sensors in control of flexible spacecraft

A recent potential of distributed image processing is discussed. Applications in the control of flexible spacecraft are emphasized. Devices are currently being developed at NASA and in universities and industries that allow the real-time processing of holographic images. Within 5 years, it is expected that, in real-time, one may add or subtract holographic images at optical accuracy. Images are stored and processed in crystal mediums. The accuracy of their storage and processing is dictated by the grating level of laser holograms. It is far greater than that achievable using current analog-to-digital, pixel oriented, image digitizing and computing techniques. Processors using image processing algebra can conceptually be designed to mechanize Fourier transforms, least square lattice filters, and other complex control system operations. Thus, actuator command inputs derived from complex control laws involving distributed holographic images can be generated by such an image processor. Plans are revealed for the development of a Conjugate Optics Processor for control of a flexible object

Numerical study of dynamo action at low magnetic Prandtl numbers

We present a three--pronged numerical approach to the dynamo problem at low magnetic Prandtl numbers $P_M$. The difficulty of resolving a large range of scales is circumvented by combining Direct Numerical Simulations, a Lagrangian-averaged model, and Large-Eddy Simulations (LES). The flow is generated by the Taylor-Green forcing; it combines a well defined structure at large scales and turbulent fluctuations at small scales. Our main findings are: (i) dynamos are observed from $P_M=1$ down to $P_M=10^{-2}$; (ii) the critical magnetic Reynolds number increases sharply with $P_M^{-1}$ as turbulence sets in and then saturates; (iii) in the linear growth phase, the most unstable magnetic modes move to small scales as $P_M$ is decreased and a Kazantsev $k^{3/2}$ spectrum develops; then the dynamo grows at large scales and modifies the turbulent velocity fluctuations.Comment: 4 pages, 4 figure

Directional characteristics of lunar thermal emission

Directional characteristics and brightness temperatures of thermal lunar emissio

ERP evidence suggests executive dysfunction in ecstasy polydrug users

Background: Deficits in executive functions such as access to semantic/long-term memory have been shown in ecstasy users in previous research. Equally, there have been many reports of equivocal findings in this area. The current study sought to further investigate behavioural and electro-physiological measures of this executive function in ecstasy users. Method: Twenty ecstasy–polydrug users, 20 non-ecstasy–polydrug users and 20 drug-naïve controls were recruited. Participants completed background questionnaires about their drug use, sleep quality, fluid intelligence and mood state. Each individual also completed a semantic retrieval task whilst 64 channel Electroencephalography (EEG) measures were recorded. Results: Analysis of Variance (ANOVA) revealed no between-group differences in behavioural performance on the task. Mixed ANOVA on event-related potential (ERP) components P2, N2 and P3 revealed significant between-group differences in the N2 component. Subsequent exploratory univariate ANOVAs on the N2 component revealed marginally significant between-group differences, generally showing greater negativity at occipito-parietal electrodes in ecstasy users compared to drug-naïve controls. Despite absence of behavioural differences, differences in N2 magnitude are evidence of abnormal executive functioning in ecstasy–polydrug users

Overcoming the su(2^n) sufficient condition for the coherent control of n-qubit systems

We study quantum systems with even numbers N of levels that are completely state-controlled by unitary transformations generated by Lie algebras isomorphic to sp(N) of dimension N(N+1)/2. These Lie algebras are smaller than the respective su(N) with dimension N^2-1. We show that this reduction constrains the Hamiltonian to have symmetric energy levels. An example of such a system is an n-qubit system. Using a geometric representation for the quantum wave function of a finite system, we present an explicit example that shows a two-qubit system can be controlled by the elements of the Lie algebra sp(4) (isomorphic to spin(5) and so(5)) with dimension ten rather than su(4) with dimension fifteen. These results enable one to envision more efficient algorithms for the design of fields for quantum-state engineering, and they provide more insight into the fundamental structure of quantum control.Comment: 13 pp., 2 figure

Disclosure of non-recent (historic) childhood sexual abuse: What should researchers do?

Non-recent (historic) childhood sexual abuse is an important issue to research, though often regarded as taboo and frequently met with caution, avoidance or even opposition from research ethics committees. Sensitive research, such as that which asks victim-survivors to recount experiences of abuse or harm, has the propensity to be emotionally challenging for both the participant and the researcher. However, most research suggests that any distress experienced is usually momentary and not of any clinical significance. Moreover, this type of research offers a platform for voices which have often been silenced, and many participants report the cathartic effect of recounting their experiences in a safe, non-judgemental space. With regard to the course of such research, lines of inquiry which ask adult participants to discuss their experiences of childhood sexual abuse may result in a first-time disclosure of that abuse by the victim-survivor to the researcher. Guidance about how researchers should respond to first-time disclosure is lacking. In this article, we discuss our response to one research ethics committee which had suggested that for a qualitative study for which we were seeking ethical approval (investigating experiences of pregnancy and childbirth having previously survived childhood sexual abuse), any disclosure of non-recent (historic) childhood sexual abuse which had not been previously reported would result in the researcher being obliged to report it to relevant authorities. We assess this to be inconsistent with both law and professional guidance in the United Kingdom; and provide information and recommendations for researchers and research ethics committees to consider

Disclosure of non-recent (historic) childhood sexual abuse: What should researchers do?

Non-recent (historic) childhood sexual abuse is an important issue to research, though often regarded as taboo and frequently met with caution, avoidance or even opposition from research ethics committees. Sensitive research, such as that which asks victim-survivors to recount experiences of abuse or harm, has the propensity to be emotionally challenging for both the participant and the researcher. However, most research suggests that any distress experienced is usually momentary and not of any clinical significance. Moreover, this type of research offers a platform for voices which have often been silenced, and many participants report the cathartic effect of recounting their experiences in a safe, non-judgemental space. With regard to the course of such research, lines of inquiry which ask adult participants to discuss their experiences of childhood sexual abuse may result in a first-time disclosure of that abuse by the victim-survivor to the researcher. Guidance about how researchers should respond to first-time disclosure is lacking. In this article, we discuss our response to one research ethics committee which had suggested that for a qualitative study for which we were seeking ethical approval (investigating experiences of pregnancy and childbirth having previously survived childhood sexual abuse), any disclosure of non-recent (historic) childhood sexual abuse which had not been previously reported would result in the researcher being obliged to report it to relevant authorities. We assess this to be inconsistent with both law and professional guidance in the United Kingdom; and provide information and recommendations for researchers and research ethics committees to consider