The use of carbon and tungsten filaments mounted in vacuum as early incandescent lamps is well-known, but it is less often realised that an early competitor was Nernst’s ceramic lamp. This made use of the property that , although good insulators at room temperature, many oxides become partially conductive when strongly heated. This is due to the migration of ions rather than electrons, and was ...

Ultraviolet germicidal irradiation (UVGI) uses UVC radiation produced by low pressure Hg vapor lamps to control biological air contaminants. Lamp UV output depends on multiple factors, including accumulated operating time (age) and the thermal effects of ambient air temperature and velocity. Additionally, the life of some lamp types depends on the frequency of on-off cycles. Models of lamp life...

Introduction In radiography, dose and image quality are dependent on radiographic parameters. The problem is caused from incorrect use of radiography equipment and from the radiation exposure to patients much more than required. Therefore, the aim of this study was to implement a quality-control program to detect changes in exposure parameters, which may affect diagnosis or patient radiation do...

We describe a new paradigm for three-dimensional computer graphics, using projectors to graphically animate physical objects in the real world. The idea is to replace a physical object—with its inherent color, texture, and material properties—with a neutral object and projected imagery, reproducing the original (or alternative) appearance directly on the object. Because the approach is to effec...

A hybrid method, applied thermal modeling and temperature measurement, is proposed to estimate the junction temperature (Tj) of high-power light-emitting diodes (LEDs) at system level, and further project long term lumen maintenance of LED lamps. First, 3D finite element modeling on commercial LED lamps is performed based on lamp structure and material information to find a steady and reliable ...

Lighting is one of the most efficient methods to conserve energy. The Philips Research reports that switching from traditional lamps (incandescent and fluorescent lamps) to solidstate lamps using LEDs (LED lamps) has an immediate impact on energy use, CO2 emissions and the environment and it also improves light quality [9]. Therefore, the Philips Research aggressively forecasts that the LED lam...

background: photoreactivation of microorganisms following uv disinfection is a disadvantage of using uv technology for wastewater treatment, since in some cases it may even reach several logarithms. the aim of this study was to evaluate the possibility of the photoreactivation of indicator bacteria (coliform and streptococci) in the irradiated effluent. methods: this study was performed using t...