NASA Laboratory Astrophysics Workshop 2006 Introductory Remarks

NASA Laboratory Astrophysics Workshop 2006, is the fourth in a series of workshops held at four year intervals, to assess the laboratory needs of NASA's astrophysics missions - past, current and future. Investigators who need laboratory data to interpret their observations from space missions, theorists and modelers, experimentalists who produce the data, and scientists who compile databases have an opportunity to exchange ideas and understand each other's needs and limitations. The multi-wavelength character of these workshops allows cross-fertilization of ideas, raises awareness in the scientific community of the rapid advances in other fields, and the challenges it faces in prioritizing its laboratory needs in a tight budget environment. Currently, we are in the golden age of Space Astronomy, with three of NASA s Great Observatories, Hubble Space Telescope (HST), Chandra X-Ray Observatory (CXO), and Spitzer Space Telescope (SST), in operation and providing astronomers and opportunity to perform synergistic observations. In addition, the Far Ultraviolet Spectroscopic Explorer (FUSE), XMM-Newton, HETE-2, Galaxy Evolution Explorer (GALEX), INTEGRAL and Wilkinson Microwave Anisotropy Probe (WMAP), are operating in an extended phase, while Swift and Suzaku are in their prime phase of operations. The wealth of data from these missions is stretching the Laboratory Astrophysics program to its limits. Missions in the future, which also need such data include the James Webb Space Telescope (JWST), Space Interferometry Mission (SIM), Constellation-X (Con-X), Herschel, and Planck. The interpretation of spectroscopic data from these missions requires knowledge of atomic and molecular parameters such as transition probabilities, f-values, oscillator strengths, excitation cross sections, collision strengths, which have either to be measured in the laboratory by simulating space plasma and interactions therein, or by theoretical calculations and modeling. Once the laboratory data are obtained, a key step to making them available to the observer is the creation and maintenance of critically compiled databases. Other areas of study, that are important for understanding planet formation, and for detection of molecules that are indicators of life, are also supported by the Laboratory Astrophysics program. Some examples are: studies of ices and dust grains in a space environment; nature and evolution of interstellar carbon-rich dust; and polycyclic aromatic hydrocarbons. In addition, the program provides an opportunity for the investigation of novel ideas, such as simulating radiative shock instabilities in plasmas, in order to understand jets observed in space. A snapshot of the currently funded program, mission needs, and relevance of laboratory data to interpreting observations, will be obtained at this workshop through invited and contributed talks and poster papers. These will form the basis for discussions in splinter groups. The Science Organization Committee will integrate the results of the discussions into a coherent White Paper, which will provide guidance to NASA in structuring the Laboratory Astrophysics program in subsequent years, and also to the scientific community in submitting research proposals to NASA for funding

Study of reactions between heavy nuclei

A semi classical approach, has been used to study those reactions between heavy nuclei (or "heavy ions" as they are more commonly referred to) in which a single nucleon or a single cluster of nucleons is transferred from one nucleus to the other. A method has been developed for evaluating transfer amplitudes for the transfer of a neutron using the semi classical theory of Brink and Pixton. As this leads to a tedious three dimensional integral, we have developed another method for the same calculation. It is found that if we work in momentum space and assume a straight line trajectory for the relative motion, the expressions simplify considerably and we are left with a straightforward single integral for the transfer amplitude. An added advantage is that the formulae are exactly the same in the post and prior representations. The theory has then been generalised for the transfer of a charged particle. Some numerical calculations have been performed for the reaction 208Pb(11B, 10B)209Pb at 114 MeV laboratory energy. A comparison of the transfer amplitudes calculated in the post and prior representations using the first method has been made. The agreement is reasonably good between these two results as well as between these and the results using the second method. We go on to set up a semi classical theory for evaluating angular distributions. The starting point is the expression of the transition matrix in DWBA. A partial wave expansion is made for the distorted waves and the WKB approximation used for the radial wave functions. Further simplifications are made resulting in a formula for the transition amplitude which is a partial wave sum containing a term recognisable as the semi classical transfer amplitude evaluated earlier. The method has been used to calculate angular distributions for the reactions 26Mg(11B, 10B)27Mg and 26Mg(11B, 10Be)27Ai at 114MeV laboratory energy. A detailed numerical study of the formula shows some interesting features which enable us to approximate the transfer amplitude by a simple parametrised exponential formula. The resulting angular distributions are compared with experiment showing good agreement. A parametrisation of the elastic scattering phase shifts as well make it possible to obtain a closed expression for the angular distribution. A numerical comparison of the angular distribution obtained from this formula is made with former results. The agreement is good. We also study the theoretical reaction 160(170*, 160)170* for a range of energies from 212.5 MeV to 37.1875 MeV and compare our results with that using the quantum mechanical code LOLA of De Vries (DeVries, 1973). The elastic scattering phase shifts are calculated in a potential with an energy dependent imaginary part. The agreement is good till 53.125 MeV. At 37.1875 MeV there is disagreement. This is attributed to the breakdown of our formalism for weakly absorbing potentials. Some calculations have been performed for the α-particle transfer reaction 160(160, 12C)20Ne. Comparison with LOLA shows disagreement which we have not been able to explain

Hybrid coagulation ultrafiltration for tenun dye waste water treatment

Hybrid Coagulation UF process has been studied to improve membrane performance and water quality for surface water treatment. Using coagulation before UF increases permeate quality; the extent of dissolved organic matter removal is controlled by the coagulation step. Efficient coagulation conditions for coagulation / settling process can be applied for the hybrid coagulation UF process. Floc cake resistance is lower than resistance due to the unsettled floc and the uncoagulated organics. For this research the hybrid process was applied in attempt to treating the effluent wastewater that discharged from the textile industries. The Hybrid Coagulation UF model was setup using the apparatus that already prepared at environmental laboratory. The waste water sample with addition of predetermined dosage of Aluminum Sulphate (Al 2(SO4)3 ) which has been left for 24 hours and 48 hours was filtered using the membrane filter with pore size 0.1 - 0.4 j.i with the bar pressure used is between 3 - 4 bars. The filtered sample was taken to measure the parameters which are COD, BOD, TSS and Colour. Then the results were compared between the raw sample and after treatment sample. The application of the hybrid system, combining coagulation and ultrafiltration, offers better effects of the removal of organic pollution

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Study of reactions between heavy nuclei

A semi classical approach, has been used to study those reactions between heavy nuclei (or "heavy ions" as they are more commonly referred to) in which a single nucleon or a single cluster of nucleons is transferred from one nucleus to the other. A method has been developed for evaluating transfer amplitudes for the transfer of a neutron using the semi classical theory of Brink and Pixton. As this leads to a tedious three dimensional integral, we have developed another method for the same calculation. It is found that if we work in momentum space and assume a straight line trajectory for the relative motion, the expressions simplify considerably and we are left with a straightforward single integral for the transfer amplitude. An added advantage is that the formulae are exactly the same in the post and prior representations. The theory has then been generalised for the transfer of a charged particle. Some numerical calculations have been performed for the reaction 208Pb(11B, 10B)209Pb at 114 MeV laboratory energy. A comparison of the transfer amplitudes calculated in the post and prior representations using the first method has been made. The agreement is reasonably good between these two results as well as between these and the results using the second method. We go on to set up a semi classical theory for evaluating angular distributions. The starting point is the expression of the transition matrix in DWBA. A partial wave expansion is made for the distorted waves and the WKB approximation used for the radial wave functions. Further simplifications are made resulting in a formula for the transition amplitude which is a partial wave sum containing a term recognisable as the semi classical transfer amplitude evaluated earlier. The method has been used to calculate angular distributions for the reactions 26Mg(11B, 10B)27Mg and 26Mg(11B, 10Be)27Ai at 114MeV laboratory energy. A detailed numerical study of the formula shows some interesting features which enable us to approximate the transfer amplitude by a simple parametrised exponential formula. The resulting angular distributions are compared with experiment showing good agreement. A parametrisation of the elastic scattering phase shifts as well make it possible to obtain a closed expression for the angular distribution. A numerical comparison of the angular distribution obtained from this formula is made with former results. The agreement is good. We also study the theoretical reaction 160(170*, 160)170* for a range of energies from 212.5 MeV to 37.1875 MeV and compare our results with that using the quantum mechanical code LOLA of De Vries (DeVries, 1973). The elastic scattering phase shifts are calculated in a potential with an energy dependent imaginary part. The agreement is good till 53.125 MeV. At 37.1875 MeV there is disagreement. This is attributed to the breakdown of our formalism for weakly absorbing potentials. Some calculations have been performed for the α-particle transfer reaction 160(160, 12C)20Ne. Comparison with LOLA shows disagreement which we have not been able to explain

Study of reactions between heavy nuclei

A semi classical approach, has been used to study those reactions between heavy nuclei (or "heavy ions" as they are more commonly referred to) in which a single nucleon or a single cluster of nucleons is transferred from one nucleus to the other. A method has been developed for evaluating transfer amplitudes for the transfer of a neutron using the semi classical theory of Brink and Pixton. As this leads to a tedious three dimensional integral, we have developed another method for the same calculation. It is found that if we work in momentum space and assume a straight line trajectory for the relative motion, the expressions simplify considerably and we are left with a straightforward single integral for the transfer amplitude. An added advantage is that the formulae are exactly the same in the post and prior representations. The theory has then been generalised for the transfer of a charged particle. Some numerical calculations have been performed for the reaction 208Pb(11B, 10B)209Pb at 114 MeV laboratory energy. A comparison of the transfer amplitudes calculated in the post and prior representations using the first method has been made. The agreement is reasonably good between these two results as well as between these and the results using the second method. We go on to set up a semi classical theory for evaluating angular distributions. The starting point is the expression of the transition matrix in DWBA. A partial wave expansion is made for the distorted waves and the WKB approximation used for the radial wave functions. Further simplifications are made resulting in a formula for the transition amplitude which is a partial wave sum containing a term recognisable as the semi classical transfer amplitude evaluated earlier. The method has been used to calculate angular distributions for the reactions 26Mg(11B, 10B)27Mg and 26Mg(11B, 10Be)27Ai at 114MeV laboratory energy. A detailed numerical study of the formula shows some interesting features which enable us to approximate the transfer amplitude by a simple parametrised exponential formula. The resulting angular distributions are compared with experiment showing good agreement. A parametrisation of the elastic scattering phase shifts as well make it possible to obtain a closed expression for the angular distribution. A numerical comparison of the angular distribution obtained from this formula is made with former results. The agreement is good. We also study the theoretical reaction 160(170*, 160)170* for a range of energies from 212.5 MeV to 37.1875 MeV and compare our results with that using the quantum mechanical code LOLA of De Vries (DeVries, 1973). The elastic scattering phase shifts are calculated in a potential with an energy dependent imaginary part. The agreement is good till 53.125 MeV. At 37.1875 MeV there is disagreement. This is attributed to the breakdown of our formalism for weakly absorbing potentials. Some calculations have been performed for the α-particle transfer reaction 160(160, 12C)20Ne. Comparison with LOLA shows disagreement which we have not been able to explain

NASA's Laboratory Astrophysics Workshop: Opening Remarks

The Astronomy and Physics Division at NASA Headquarters has an active and vibrant program in Laboratory Astrophysics. The objective of the program is to provide the spectroscopic data required by observers to analyze data from NASA space astronomy missions. The program also supports theoretical investigations to provide those spectroscopic parameters that cannot be obtained in the laboratory; simulate space environment to understand formation of certain molecules, dust grains and ices; and production of critically compiled databases of spectroscopic parameters. NASA annually solicits proposals, and utilizes the peer review process to select meritorious investigations for funding. As the mission of NASA evolves, new missions are launched, and old ones are terminated, the Laboratory Astrophysics program needs to evolve accordingly. Consequently, it is advantageous for NASA and the astronomical community to periodically conduct a dialog to assess the status of the program. This Workshop provides a forum for producers and users of laboratory data to get together and understand each others needs and limitations. A multi-wavelength approach enables a cross fertilization of ideas across wavelength bands