Impact and penetration by L/D ≤ 1 projectiles

Calculations of steel target penetration by L/D ≤ 1 tungsten and tungsten alloy projectiles have been extended to L/D = 1/32 over the velocity range 1.5 to 5 km/s. The ratio of crater to projectile diameter tends to 1 as L/D decreases over this entire velocity range. For impact velocities of 1.5 and 3 km/s, penetration depth normalized by projectile length, P/L, increases with decreasing projectile L/D up to a maximum value and then decreases for still lower L/D. Experiments at impact velocities of 2 and 3 km/s confirm these results. For 5 km/s impact velocity, the calculations show P/L increasing with decreasing projectile L/D over the entire range 1/32 ≤ L/D ≤ 1. The projectile L/D for which the maximum P/L occurs appears to depend on the impact velocity. P/L generally scales with impact velocity as P/L v^f(L/D) where f(L/D) ranges from 0 for a long rod to, we believe, 2 in the limit as projectile L/D approaches zero. The calculations show for 1/8 ≤ L/D ≤ 1/2, P/L v^0.9; for L/D = 1/16, P/L v^1.5; and for L/D = 1/32, the new results give P/L v^1.9.     

Body of knowledge for software quality measurement

Measuring quality is the key to developing high-quality software. The author describes two approaches that help to identify the body of knowledge software engineers need to achieve this goal. The first approach derives knowledge requirements from a set of issues identified during two standards efforts: the IEEE Std. 1061-1998 for a Software Quality Metrics Methodology and the American National Standard Recommended Practice for Software Reliability (ANSI/AIAA R-013-1992). The second approach ties these knowledge requirements to phases in the software development life cycle. Together, these approaches define a body of knowledge that shows software engineers why and when to measure quality. Focusing on the entire software development life cycle, rather than just the coding phase, gives software engineers the comprehensive knowledge they need to enhance software quality and supports early detection and resolution of quality problems. The integration of product and process measurements lets engineers assess the interactions between them throughout the life cycle. Software engineers can apply this body of knowledge as a guideline for incorporating quality measurement in their projects. Professional licensing and training programs will also find it useful     

Perceived control in indoor environments: a conceptual approach

Building automation systems provide the potential to optimize the energy consumption of buildings as well as to detect failures in the operation of buildings. The system comprising building form–HVAC–building automation–user is becoming more complex. Providing the occupants with control over the indoor environment is widely accepted for its positive effect on their satisfaction. This paper explores what the term ‘perceived control’ means conceptually and draws implications for its application to the design and management of buildings. Personality- and environmental-psychology emphasize the importance of personal control to humans. The adaptive model of thermal comfort, findings from post-occupancy evaluations and surveys in real buildings also indicate the importance of high levels of perceived control. These models and findings exist in parallel and have not yet been interconnected and translated into models for the built environment. A new conceptual approach to explain perceived control is proposed. Satisfaction with the indoor environment occurs not only when ‘comfort’ is provided but also immediately after a successful control action, even if homeostasis has not yet been achieved (pleasure). Giving control to occupants can result in higher levels of satisfaction.     

Applying reliability models to the space shuttle

The experience of a team that evaluated many reliability models and tried to validate them for the on-board system software of the National Aeronautics and Space Administration's (NASA's) space shuttle is presented. It is shown that three separate but related functions comprise an integrated reliability program: prediction, control, and assessment. The application of the reliability model and the allocation of test resources as part of a testing strategy are discussed     

The Use of Simulation in the Evaluaton of Software

Two particularly nagging ailments faced by the computer industry today are the high cost and late delivery of software.^1,2The symptoms usually surface during software debugging, testing, and integration; but the ailments themselves can most often be traced back to the program design phase and the structural characteristics of the program. The significance of program structural characteristics has been recognized for some time, as witnessed by the emergence of structured programming,^3,4,a methodology that sets out to (1) reduce programming errors; (2) design an understandable, readable, and therefore maintainable program; (3) increase our ability to detect errors; and (4) prove, if only informally, that the program is correct. But there is another tool available that has usually been overlooked in the software development process: simulation.     

Isolation and baking performance of ginsenosides from Panax ginseng

The baking performance of two powder extracts from Panax ginseng with different concentrations and different compositions of ginsenosides was studied by means of microscale baking tests with 10 g of flour. Compared to a control bread without additive, the extracts increased the bread volume by 50 and 62 %, respectively. In each case, the maximum bread volume was reached when at least 0.3 % ginsenosides (based on flour) was added. A multistage fractionation of the more effective ginseng extract and microscale baking tests of the fractions showed that ginsenosides were the baking active compounds. Further fractionation of the ginsenosides revealed that the baking activity was not evoked by a single ginsenoside class but by a combination of several ginsenoside classes. However, baking activity varied when different ginsenoside classes were added as single fractions. Ginsenosides seem to interact in aqueous media providing very stable aggregates, which appear to exhibit surface activity and, thus, an improving effect in baking. This study showed the excellent baking performance of ginsenosides for the first time and suggests them as naturally occurring baking active ingredients in breadmaking.     

And Yet It Moves: Oxidation of the Nuclear Autoantigen La/SS-B Is the Driving Force for Nucleo-Cytoplasmic Shuttling

Decades ago, we and many other groups showed a nucleo-cytoplasmic translocation of La protein in cultured cells. This shuttling of La protein was seen after UV irradiation, virus infections, hydrogen peroxide exposure and the Fenton reaction based on iron or copper ions. All of these conditions are somehow related to oxidative stress. Unfortunately, these harsh conditions could also cause an artificial release of La protein. Even until today, the shuttling and the cytoplasmic function of La/SS-B is controversially discussed. Moreover, the driving mechanism for the shuttling of La protein remains unclear. Recently, we showed that La protein undergoes redox-dependent conformational changes. Moreover, we developed anti-La monoclonal antibodies (anti-La mAbs), which are specific for either the reduced form of La protein or the oxidized form. Using these tools, here we show that redox-dependent conformational changes are the driving force for the shuttling of La protein. Moreover, we show that translocation of La protein to the cytoplasm can be triggered in a ligand/receptor-dependent manner under physiological conditions. We show that ligands of toll-like receptors lead to a redox-dependent shuttling of La protein. The shuttling of La protein depends on the redox status of the respective cell type. Endothelial cells are usually resistant to the shuttling of La protein, while dendritic cells are highly sensitive. However, the deprivation of intracellular reducing agents in endothelial cells makes endothelial cells sensitive to a redox-dependent shuttling of La protein.