A multilevel control system for the large space telescope

A multilevel scheme was proposed for control of Large Space Telescope (LST) modeled by a three-axis-six-order nonlinear equation. Local controllers were used on the subsystem level to stabilize motions corresponding to the three axes. Global controllers were applied to reduce (and sometimes nullify) the interactions among the subsystems. A multilevel optimization method was developed whereby local quadratic optimizations were performed on the subsystem level, and global control was again used to reduce (nullify) the effect of interactions. The multilevel stabilization and optimization methods are presented as general tools for design and then used in the design of the LST Control System. The methods are entirely computerized, so that they can accommodate higher order LST models with both conceptual and numerical advantages over standard straightforward design techniques

Survey of indoor concentrations of radon and thoron in homes in Bangalore, India

Due to the legislation and general concern of radiation levels in dwellings in India, there is a need to continuously monitor the indoor concentrations of radon and Thoron in different geographical areas of Bangalore, which could be of great significance to exposure to occupants, particularly in living places. This paper presents the 222Rn and 220Rn concentrations measured in houses in 10 different locations in Bangalore. The data was continuously obtained for a period of 2 years since 2007, covering more than 150 dwellings. The arithmetic mean values of 222Rn and 220Rn were found to be 35.0 and 21.5 Bqm -. The effective dose rate received by the population in the study area ranged between 0.1-0.5 mSv y -1, the arithmetic mean concentration was 0.2±0.03mSv y -1. The result shows no significant radiological risk for the inhabitants. © SAGE Publications 2010

Volumetric Variations of Indoor Radon and Thoron

The volumetric variations of indoor radon and thoron were measured in rooms ranging in volume from 30-310 m 3 in different dwellings at various locations in Bangalore, India. The rooms selected were similar in quality of construction, age, type of walls, and type of floor. Twin cup plastic track detectors were installed in the rooms of 42 dwellings to record indoor 222Rn and 220Rn levels. Higher concentrations were observed in rooms with lower volumes than in rooms with higher volumes. The 222Rn and 220Rn concentrations in the dwellings ranged from 4.0-93.0 Bq m -3, whereas the concentrations of their daughter products ranged from 0.01-2.5 mWL. When the room volume increased tenfold, the concentration of 222Rn reduced by 23 and that of 220Rn reduced by 13, provided all other conditions remained the same. The concentrations did not increase linearly with the volumes of the rooms. The annual effective exposure dose rate because of 222Rn, 220Rn and their daughter products ranged from 0.1-0.4 mSv year -1 with a mean of 0.2 ± 0.1 mSv year -1. © 2011 King Fahd University of Petroleum and Minerals

Concentration of radon, thoron and their progeny levels in different types of floorings, walls, rooms and building materials

Background: Radon, thoron and their progenies are the most important contributions to human exposure from natural sources. Radon exists in soil gas, building materials, Indoor atmosphere etc. Among all the natural sources of radiation dose to human beings, inhalation of radon contributes a lot. The work presented here emphasizes the long term measurements of radon, thoron and their progeny concentrations in about 100 dwellings using solid state nuclear track detectors. Materials and Methods: Measurements were made using dosimeters and the concentrations were estimated by knowing the track density of films through spark counter, and sensitivity factor for bare, filter and membrane films. Results: Presence of radon and thoron in houses is the effect of several aspects such as the activity concentrations of uranium, radium and thorium in the local soil, building materials, ventilation of houses and also entry of radon into houses through the cracks in floor/wall. Conclusion: The observations reveal that the concentrations of radon and/or thoron are relatively higher in granite than in concrete, cement and bricks. In continuation to this the concentration observed in bathrooms is more compared to kitchen, bedroom and living rooms. This study discloses that the residential rooms of good ventilation will avoid the health hazards due to radon and its rich materials

Primary structure of sesbania mosaic virus coat protein: its implications to the assembly and architecture of the virus

Sesbania mosaic virus (SMV) is a plant virus that infects Sesbania grandiflora plants in Andhra Pradesh, India. The amino acid sequence of the coat protein of SMV was determined using purified peptides generated by cleavage with trypsin, chymotrypsin, V8 protease and clostripain. The 230 residues so far determined were compared to the corresponding residues of southern bean mosaic virus (SBMV), the type member of sobemoviruses. The overall identity between the sequences is 61.7%. The amino terminal 64 residues, which constitute an independent domain (R-domain) known to interact with RNA, are conserved to a lower extent (52.5%). Comparison of the positively charged residues in this domain suggests that the RNA-protein interactions are considerably weaker in SMV. The residues that constitute the major domain of the coat protein, the surface domain (S-domain, residues 65-260), are better conserved (66.5%). The positively charged residues of this domain that face the nucleic acid are well conserved. The longest conserved stretch of residues (131- 142) corresponds to the loop involved in intersubunit interactions between subunits related by the quasi 3-fold symmetry. A unique cation binding site located on the quasi 3-fold axis contributes to the stability of SMV. These differences are reflected in the increased stability of the SMV coat protein and its ability to be reconstituted with RNA at pH 7.5. A major epitope was identified using monoclonal antibodies to SMV in the segment 201-223 which contains an exposed helix in the capsid structure

Primary structure of sesbania mosaic virus coat protein: its implications to the assembly and architecture of the virus

Sesbania mosaic virus (SMV) is a plant virus that infects Sesbania grandiflora plants in Andhra Pradesh, India. The amino acid sequence of the coat protein of SMV was determined using purified peptides generated by cleavage with trypsin, chymotrypsin, V8 protease and clostripain. The 230 residues so far determined were compared to the corresponding residues of southern bean mosaic virus (SBMV), the type member of sobemoviruses. The overall identity between the sequences is 61.7%. The amino terminal 64 residues, which constitute an independent domain (R-domain) known to interact with RNA, are conserved to a lower extent (52.5%). Comparison of the positively charged residues in this domain suggests that the RNA-protein interactions are considerably weaker in SMV. The residues that constitute the major domain of the coat protein, the surface domain (S-domain, residues 65-260), are better conserved (66.5%). The positively charged residues of this domain that face the nucleic acid are well conserved. The longest conserved stretch of residues (131-142) corresponds to the loop involved in intersubunit interactions between subunits related by the quasi 3-fold symmetry. A unique cation binding site located on the quasi 3-fold axis contributes to the stability of SMV. These differences are reflected in the increased stability of the SMV coat protein and its ability to be reconstituted with RNA at pH 7.5. A major epitope was identified using monoclonal antibodies to SMV in the segment 201-223 which contains an exposed helix in the capsid structure. This region is highly conserved between SMV and SBMV (70%) suggesting that it could represent the site of an important function such as vector recognition