Safety cases are now regularly used to communicate the argument about the achievement of acceptable levels of safety for safety critical systems. Increasingly, safety standards such as Defence Standard 00-56 require the scope of the safety case to cover not only the development of the system, but also operating and maintenance through life, including decommissioning. This involves two dimension...

In previous papers, we asserted that software system safety is primarily concerned with epistemic questions, that is, questions concerning knowledge and the degree of confidence that can be placed in that knowledge. We also enumerated a set of 21 foundational epistemic questions, discussed some of the difficulties that exist in answering these questions adequately today, and speculated briefly ...

Introduction: Glasses on Mars, formed by impact melting and volcanism, likely make up a significant fraction of the regolith because they accumulate over time and there have been few processes operating in the last ~3.5 Ga to destroy them [1]. These glasses have exciting astrobiological implications because they can host microbial colonies and preserve biosignatures [2-5]; they may have also se...

in all biological systems growth is defined as increase of chemical compounds. bacteria can achieve to balanced growth if they are growing in a medium, which are completely adapted to it. clostridium chauvoei, (clostridium feseri) is an anaerobic, spore forming, motile, and polymorph bacteria, which its size varies from 0.5-1 to 3-8 micron and could be observed as individual bacterium, diplo, a...

Objective(s): The aim of this study was to synthesis new dental nanocomposites reinforced with fabricated glass nanoparticles and compare two methods for fabrication and investigate the effect of this filler on mechanical properties. Materials and Methods: The glass nanoparticles were produced by wet milling process. The particle size and shape was achieved using PSA and SEM. Glass nanoparticle...

Background: Lead glass has a wide variety of applications in radiation protection. This study aims to investigate some characteristics of lead glass such as the γ-ray energy-dependent mass and linear attenuation coefficients, the half-value layer thickness, and the absorbed dose distribution for specific energy. Materials and Methods: The attenuation parameters of different lead glass types aga...

A concept of transparent “quantum dot glass” (TQDG) is proposed for a combination quantum (QD)-based glass luminescent solar concentrator (LSC) and its edge-attached cells, as type photovoltaics (TPVs) building-integrated (BIPVs). Different from conventional LSCs, which typically serve pure optical devices, TQDGs have to fulfill requirements both power-generating components building constructio...

different glasses suitable for temperature sensing in the fiber optic sensors were studied in this article. the phase changes for eight different glass materials were calculated and results were compared. our results showed that extra dense flint glass is the most sensitive one, while pure silica results in the lowest phase change. in another study the effect of wavelength on the phase variatio...