Some Operational Implications of Stealth Warfare

Occasionally, a hardware development springs upon us with extraordinary and lasting impact on the way we conduct war. Some exampled include the longbow, gunpowder, the machine gun, armored vehicles and nuclear energly. In some cases, such as the machine gun, theb impact is so immense that an overwhelming offensive or defensive advantage is created until the next miricle weapon is developed in response (armored vehicles, for example, to counter the machine gun). In the most extreme of caases, an entirely new category of warfare must be define to accommodate the magnitude of change wrought by a given developement, such as the air and undersea warfare of this century, and a revalidation of all existing tactical and strategic postulates is required

The Effect of Secondary Fiber Furnish on the Tensile Energy Absorption Capacity of Paper Under Repeated Extension Cycles

The object of this study was to determine what effect does recycling paper have on the tensile energy absorption (TEA) of that paper. The TEA of the sheet was split into two components, the elastic and the plastic. The sum of the two components gives the composite TEA. The TEA\u27s were measured at three different numbers of extension-cycles. It was found that a greater number of extension cycles resulted in greater TEA\u27s for both elastic and plastic regions. It was discovered that elastic TEA does not decrease with the first or second degree of recycling. Plastic TEA suffers its greatest losses after the first and second recycles. Further work is needed to investigate which fiber properties are responsible for certain losses in TEA. There is also need to study the effects of ink removing chemicals, and dynamic sheet formers, on the physical characteristics of recycled paper

Overview of NASA's Microgravity Materials Program

The NASA Microgravity Materials Program currently funds 19 grants involving the development of experiments to be conducted on the International Space Station (ISS). These experiments are designed to utilize facilities built by partner agencies, primarily the European Space Agency. These facilities include furnace inserts to the Materials Science Research Rack, the Electro-Magnetic Levitator, and the Device for the study of Critical Liquids and Crystallization (DECLIC) facility. Projects are funded either through proposals responding to NASA announcements or unsolicited proposals associated with an international collaboration that is partially funded by a partner agency. An overview of the research content of the program, how potential investigations are solicited, reviewed and funded, and the operations of the ISS facilities is provided

Nonlinear Modeling and Verification of a Heaving Point Absorber for Wave Energy Conversion

Although the heaving Point Absorber (PA) concept is well known in wave energy conversion research, few studies focus on appropriate modelling of non-linear fluid viscous and mechanical friction dynamics. Even though these concepts are known to have non-linear effects on the hydrodynamic system, most research studies consider linearity as a starting point and in so doing have a weak approach to modelling the true dynamic behaviour, particularly close to resonance. The sole use of linear modelling leads to limited ability to develop control strategies capable of true power capture optimisation and suitable device operation. Based on a 1/50 scale cylindrical heaving PA, this research focuses on a strategy for hydrodynamic model development and experimental verification. In this study, nonlinear dynamics are considered, including the lumped effect of the fluid viscous and mechanical friction forces. The excellent correspondence between the derived non-linear model and wave tank tested PA behaviours provides a strong background for wave energy tuning and control system design

Spotlight on zebrafish:translational impact

In recent years, the zebrafish has emerged as an increasingly prominent model in biomedical research. To showcase the translational impact of the model across multiple disease areas, Disease Models & Mechanisms has compiled a Special Issue that includes thought-provoking reviews, original research reporting new and important insights into disease mechanisms, and novel resources that expand the zebrafish toolkit. This Editorial provides a summary of the issue’s contents, highlighting the diversity of zebrafish disease models and their clinical applications