Apollo experience report: Certification test program

A review of the Apollo spacecraft certification (qualification) test program is presented. The approach to devising the spectrum of dynamic and climatic environments, the formulation of test durations, and the relative significance of the formal certification test program compared with development testing and acceptance testing are reviewed. Management controls for the formulation of test requirements, test techniques, data review, and acceptance of test results are considered. Significant experience gained from the Apollo spacecraft certification test program which may be applicable to future manned spacecraft is presented

Viscosity and thermal conductivity coefficients of gaseous and liquid oxygen

Equations and tables are presented for the viscosity and thermal conductivity coefficients of gaseous and liquid oxygen at temperatures between 80 K and 400 K for pressures up to 200 atm. and at temperatures between 80 K and 2000 K for the dilute gas. A description of the anomalous behavior of the thermal conductivity in the critical region is included. The tabulated coefficients are reliable to within about 15% except for a region in the immediate vicinity of the critical point. Some possibilities for future improvements of this reliability are discussed

Inheritance of Flower Color in Musk Thistle (\u3ci\u3eCarduus thoermeri\u3c/i\u3e)

Four flower-color phenotypes were observed in a population of musk thistle (Carduus tboermeri Weinm.). This plant has been commonly referred to as C. nutans L. The four phenotypes were: purple corolla and purple pollen, pink corolla and white pollen, white corolla and purple pollen, and white corolla and white pollen. In four generations, 177 self-pollinated individuals of these four phenotypes produced 2123 progeny plants that were classified. Results support the hypothesis that three independent gene pairs were involved in deter- mining the four flower phenotypes. The gene pairs have been designated P/p, W/w, and Pi/pi. It was postulated that all three dominant alleles, P, W, and Pi, must be present to produce both purple corollas and purple pollen. The p allele prevents color development in both corollas and pollen; the w allele eliminates color in corollas but does not affect pollen color; and the pi allele dilutes corolla color from purple to pink and eliminates pollen color. Height measurements of progenies of self-pollinated plants indicated that decreased plant height was associated with inbreeding. On the basis of the evidence presented, the musk thistle plants used in these experiments appear to belong to a single species

Inheritance of Flower Color in Musk Thistle (\u3ci\u3eCarduus thoermeri\u3c/i\u3e)

Four flower-color phenotypes were observed in a population of musk thistle (Carduus tboermeri Weinm.). This plant has been commonly referred to as C. nutans L. The four phenotypes were: purple corolla and purple pollen, pink corolla and white pollen, white corolla and purple pollen, and white corolla and white pollen. In four generations, 177 self-pollinated individuals of these four phenotypes produced 2123 progeny plants that were classified. Results support the hypothesis that three independent gene pairs were involved in deter- mining the four flower phenotypes. The gene pairs have been designated P/p, W/w, and Pi/pi. It was postulated that all three dominant alleles, P, W, and Pi, must be present to produce both purple corollas and purple pollen. The p allele prevents color development in both corollas and pollen; the w allele eliminates color in corollas but does not affect pollen color; and the pi allele dilutes corolla color from purple to pink and eliminates pollen color. Height measurements of progenies of self-pollinated plants indicated that decreased plant height was associated with inbreeding. On the basis of the evidence presented, the musk thistle plants used in these experiments appear to belong to a single species

Multiscale Modeling of Binary Polymer Mixtures: Scale Bridging in the Athermal and Thermal Regime

Obtaining a rigorous and reliable method for linking computer simulations of polymer blends and composites at different length scales of interest is a highly desirable goal in soft matter physics. In this paper a multiscale modeling procedure is presented for the efficient calculation of the static structural properties of binary homopolymer blends. The procedure combines computer simulations of polymer chains on two different length scales, using a united atom representation for the finer structure and a highly coarse-grained approach on the meso-scale, where chains are represented as soft colloidal particles interacting through an effective potential. A method for combining the structural information by inverse mapping is discussed, allowing for the efficient calculation of partial correlation functions, which are compared with results from full united atom simulations. The structure of several polymer mixtures is obtained in an efficient manner for several mixtures in the homogeneous region of the phase diagram. The method is then extended to incorporate thermal fluctuations through an effective chi parameter. Since the approach is analytical, it is fully transferable to numerous systems.Comment: in press, 13 pages, 7 figures, 6 table

Single event effects and laser simulation studies

The single event upset (SEU) linear energy transfer threshold (LETTH) of radiation hardened 64K Static Random Access Memories (SRAM's) was measured with a picosecond pulsed dye laser system. These results were compared with standard heavy ion accelerator (Brookhaven National Laboratory (BNL)) measurements of the same SRAM's. With heavy ions, the LETTH of the Honeywell HC6364 was 27 MeV-sq cm/mg at 125 C compared with a value of 24 MeV-sq cm/mg obtained with the laser. In the case of the second type of 64K SRAM, the IBM640lCRH no upsets were observed at 125 C with the highest LET ions used at BNL. In contrast, the pulsed dye laser tests indicated a value of 90 MeV-sq cm/mg at room temperature for the SEU-hardened IBM SRAM. No latchups or multiple SEU's were observed on any of the SRAM's even under worst case conditions. The results of this study suggest that the laser can be used as an inexpensive laboratory SEU prescreen tool in certain cases

The Role of Deontic Logic in the Specification of Information Systems

In this paper we discuss the role that deontic logic plays in the specification of information systems, either because constraints on the systems directly concern norms or, and even more importantly, system constraints are considered ideal but violable (so-called `soft¿ constraints).\ud To overcome the traditional problems with deontic logic (the so-called paradoxes), we first state the importance of distinguishing between ought-to-be and ought-to-do constraints and next focus on the most severe paradox, the so-called Chisholm paradox, involving contrary-to-duty norms. We present a multi-modal extension of standard deontic logic (SDL) to represent the ought-to-be version of the Chisholm set properly. For the ought-to-do variant we employ a reduction to dynamic logic, and show how the Chisholm set can be treated adequately in this setting. Finally we discuss a way of integrating both ought-to-be and ought-to-do reasoning, enabling one to draw conclusions from ought-to-be constraints to ought-to-do ones, and show by an example the use(fulness) of this

Oxidation of graphene on metals

We use low-energy electron microscopy to investigate how graphene is removed from Ru(0001) and Ir(111) by reaction with oxygen. We find two mechanisms on Ru(0001). At short times, oxygen reacts with carbon monomers on the surrounding Ru surface, decreasing their concentration below the equilibrium value. This undersaturation causes a flux of carbon from graphene to the monomer gas. In this initial mechanism, graphene is etched at a rate that is given precisely by the same non-linear dependence on carbon monomer concentration that governs growth. Thus, during both growth and etching, carbon attaches and detaches to graphene as clusters of several carbon atoms. At later times, etching accelerates. We present evidence that this process involves intercalated oxygen, which destabilizes graphene. On Ir, this mechanism creates observable holes. It also occurs mostly quickly near wrinkles in the graphene islands, depends on the orientation of the graphene with respect to the Ir substrate, and, in contrast to the first mechanism, can increase the density of carbon monomers. We also observe that both layers of bilayer graphene islands on Ir etch together, not sequentially.Comment: 15 pages, 10 figures. Manuscript revised to improve discussion, following referee comments. Accepted for publication in Journal of Physical Chemistry C, Feb. 11, 201

Proyecto de investigación para la creación de una fototeca digital y un Sistema de Información para Archivos Fotográficos (SIAF)

Descripción extensa de un proyecto de investigación interdisciplinaria que abarcará\ud las ciencias sociales, la construcción de fuentes y la informática. Dicha investigación generará\ud diversos productos, entre ellos, una Fototeca Digital en línea y un Sistema de Información\ud para Archivos Fotográficos (SIAF); estos productos responderán a problemáticas detectadas\ud en el trabajo con las imágenes como fuentes de investigación en México