Micron-size particle filtration with dual wire artificial electretfibers

The authors present the construction, operation, and test results of a new type of electrostatic filter of very low pressure drop at usual flow-through velocities while providing excellent filtration for micron-size particles. The filter is constructed in the form of a thick mesh of dual wire fibers, electrically energized at approximately 200 V DC, and reversing the polarity at a very low frequency in the order of 5 mHz. While, in general, mechanical filters trap the particles on the air incoming surface, with subsequent rapid “blinding,” the new filter collects the particles inside the mesh volume thus offering a considerably longer life     

Oscillation of the scattering time in a 2D electron system with oval antidots

Electron scattering by a single barrier is predicted to reveal singularities as the magnetic field is changed, because the number of electron collisions with the barrier dramatically increases as chaotic orbits around the barrier are changed into periodic orbits. To test this experimentally we have measured the magnetoresistance of AlGaAs/GaAs heterostructures with a two-dimensional electron gas and a lateral lattice containing a macroscopic number of oval-shaped antidots fabricated using electron lithography. Reproducible fluctuations in the magnetoresistance are observed at low field, which are due to the oscillations of the number of electron collisions with the antidots. The number of collisions N before the electron escapes from the antidot has been calculated as a function of B in an electric field. The position of the maxima in N(B) obtained from calculations and experiment are in reasonable agreement.     

Anti-CD38 prevents the development of the adaptive response induced by X-rays in human lymphocytes

Irradiation of human lymphocytes (1 cGy X-rays, 37 degrees C) evoked an approximately 30% decrease in the frequency of micronuclei upon subsequent X-irradiation (1.5 Gy). The response was reflected in a lower micronucleus frequency but not in the DNA repair rate measured by the comet assay directly after the challenge dose. Treatment of lymphocytes with anti-CD38 antibody 1 h before irradiation with the adaptive dose prevented the development of the adaptive response measured as micronuclei frequency, but adaptation was not reflected in a lower rate of DNA repair, measured by the alkaline version of the 'comet' assay. In lymphocytes that were anti-CD38-treated and irradiated and or irradiated with the adaptive dose the rate of DNA repair was not changed. However, the mean DNA damage level in adapted anti-CD38-treated lymphocytes was significantly lower than that in the control lymphocytes at all time points. We conclude that ligation of CD38 by antibody initiates signalling that prevents the development of the adaptive response induced by X-rays. Lower chromosome damage revealed by the cytokinesis block-micronucleus test in the adapted lymphocytes is unrelated to DNA repair rate.     

Rapid detection cytomegalovirus pneumonia in recipients of bone marrow transplant: evaluation and comparison of five survey methods for bronchoalveolar lavage fluid

To detect cytomegalovirus-associated interstitial pneumonia (CMV-IP) in recipients of BMT in its earliest stage, five CMV methods were assessed for their usefulness using bronchoalveolar lavage fluid as the test specimen. Of the 43 cases enrolled in the study, PCR was positive in 12 cases, shell vial in eight, culture in eight and cytology in three. There were no positive cases in in situ hybridization. Based on this result, the 43 cases were classified into four groups: Group 1, three cases: positive in PCR, shell vial and cytology; Group 2, five cases: positive in PCR and shell vial; Group 3, four cases: positive only in PCR; and Group 4, 31 cases: negative in all CMV tests. Cases in Group 1 were judged as having the highest risk of overt CMV-IP. They were successfully treated with a combination of ganciclovir and immunoglobulin. Group 2 was diagnosed as having active CMV infection and ganciclovir monotherapy was effective for these patients. Groups 3 and 4 were not given anti-CMV therapy, but they were free from CMV-related manifestations throughout the study. The sensitivity and specificity of each survey method for the detection of Groups 1 and 2 were 1.0 and 0.89 in PCR, 1.0 and 1.0 in shell vial, 0.88 and 1.0 in culture, and 0.38 and 1.0 in cytology. Similarly, the positive and negative predictive values were 0.67 and 1.0 in PCR, 1.0 and 1.0 in shell vial, 1.0 and 0.97 in culture, and 1.0 and 0.88 in cytology. Thus, CMV survey on bronchoalveolar fluid was thought to be useful in detecting post BMT CMV-IP in its earliest stage.     

On the way to creating a system of distant power supply for space vehicles

Using power resources of the outer space and its industrialization have become an urgent task in the development of present day civilization. Solar energy is the most suitable basis for power supply for the majority of projects in the near-Earth space. Passing on to the large-scale space-based systems of power supply requires putting into life demonstration experiments in which power transmission by electromagnetic emission is supposed.In the paper the expedience of developing an autonomous power module which provides the possibility of space programs with great power consumption and wireless transmission system running-up is proved. Ukraine can design a solar power satellite of 10–20 kW power on the basis of the research satellite AUOS-SM. Two variants of design solutions for such satellite with solar arrays of great area are presented. Power transmission to the space vehicle-consumer can be conducted by cable as well as in a wireless way. The possibilities of placing microwave and laser energy transmission systems on board the satellite are analysed. It is shown that a power supply system for space vehicles with transmission distance of thousands km can be designed basing on modern lasers.Some experiments making use of great electric power generated by the plant of the satellite under consideration are proposed. The running-up of electric thrusters which are necessary for orientation and distancing is of great interest. Wireless power transmission may be carried on to a small satellite equipped with electric thrusters.     

Representing context, cognition, and crew performance in a shutdown risk assessment

This paper presents a potentially practical treatment of dynamic operator-system interactions. The approach employs a dynamic event tree framework to explicitly address plant dynamics, system indications, crew-plant interactions, time available, crew cognition, errors of commission (mistakes), and multiple planning and diagnosis possibilities. The approach is applied in an analysis of a hypothesize medium break loss of coolant accident for a test reactor that occurs during plant shutdown. This transient was selected on the basis of: a significant cognitive component being present, high consequences being associated with operator actions, and the importance of event timing to scenario progression. The results presented show how quantitative risk predictions are affected by the treatment of dynamics, and demonstrate how non-proceduralized recovery actions and a number of performance shaping factors (e.g., crew experience, stress, and confidence) can be explicitly treated. Insights and lessons learned regarding the performance of a dynamic assessment are also presented.     

高性能各向异性Sm2Fe17Nx磁粉的制备

本文研究了高性能各向异性Ｓｍ２Ｆｅ１７Ｎｘ磁粉的制备工艺路线与工艺参数。优化了制备与工艺参数。已制备出磁性能达到：Ｂｒ＝１．３９Ｔ，Ｈｃｉ＝８５０ＫＡ／ｍ和（ＢＨ）ｍ＝２３６ＫＪ／ｍ＾３的各向异性Ｓｍ２Ｆｅ１７Ｎ２．８８磁粉，该磁粉的各向异性场ＨＡ达到２０Ｔ。