COMPARISON OF DIFFERENT ROOF TYPES IN TERMS OF LIGHTING CONDITIONS IN AN INDUSTRIAL HALL

The indoor climate of industrial buildings is a function of production technology and requirements for the creation of an optimal artificial material environment. Currently, we consider daylight not only as a source of illumination, but also as an aesthetic element of a building or a way of reducing energy consumption. Light in a closed space allows a person to obtain basic visual information (perception) and perform visual tasks. Top lighting schemes can provide increasingly more useful illumination from smaller apertures than side lighting when they capture and diffuse sunlight. Sunlight is roughly 10 times brighter than light from the sky or clouds. A combined lighting system (top lighting and side lighting) ensures a better light distribution in industrial buildings. In this study, we present a comparison of daylight factors for different types of skylights. Specifically, a saddle skylight in the hall and three other types of skylights were created and simulated. In all the cases, the models of skylights were prepared and simulated using RADIANCE. Additionally, a comparison of simulation results obtained with RADIANCE was conducted to quantify the lighting climate. Overall, saddle roof was considered as the best choice for daylight in an industrial hall

Monitorowanie zanieczyszczenia środowiska za pomocą cienkich elektrod metalowych przygotowanych przez fizyczne osadzanie z fazy gazowej

This work is focused on environmental pollution monitoring utilizing thin metal electrodes on glassy/ceramic substrates prepared by physical vapour deposition. Besides others, it is well known that environmental pollution on electrical insulation is one of the problems faced by distribution utilities and electricity transmission system. Due to this reason there is a need to deal with monitoring of environmental pollution as it strongly influences their capability to withstand the high-voltage stress without the breakdown. It is the aim of present work to propose new system for environmental pollution monitoring based on application of extra-thin metal electrodes. The influence of morphology and chemical composition of pollutants on the surface resistance and conductivity of selected insulators is also discussed.Artykuł dotyczy monitorowania zanieczyszczenia środowiska za pomocą cienkich elektrod metalowych na szklanych/ceramicznych podłożach przygotowanych przez fizyczne osadzanie z fazy gazowej. Widomym jest, że zanieczyszczenie środowiska odpadami izolacji elektrycznej jest jednym z problemów, przed którymi stoją firmy dystrybucyjne i system przesyłu energii elektrycznej. Z tego powodu istnieje potrzeba monitorowania zanieczyszczenia środowiska, ponieważ ma to duży wpływ niezawodność sieci wysokiego napięcia i jej awaryjność. Celem przedstawionych prac jest zaproponowanie nowego systemu monitorowania zanieczyszczenia środowiska w oparciu o zastosowanie bardzo cienkich elektrod metalowych. Omówiono także wpływ morfologii i składu chemicznego zanieczyszczeń na rezystancję powierzchniową i przewodnictwo wybranych izolatorów

Direct observation of electric field induced pattern formation and particle aggregation in ferrofluids

Ferrofluids typically respond to magnetic fields and can be manipulated by external magnetic fields. Here, we report on formation of visually observable patterns in a diluted low-polarity ferrofluid exposed to external electric fields. This presents a specific type of ferrofluid structure driven by a combined effect of electrohydrodynamics and electrical body forces. The free charge and permittivity variation are considered to play a key role in the observed phenomenon. The corresponding changes in the ferrofluid structure have been found at nanoscale as well. By small-angle neutron scattering (SANS), we show that the magnetic nanoparticles aggregate in direct current (dc) electric field with a strong dependence on the field intensity. The anisotropic aggregates preferably orient in the direction of the applied electric field. Conducting SANS experiments with alternating current (ac) electric fields of various frequencies, we found a critical frequency triggering the aggregation process. Our experimental study could open future applications of ferrofluids based on insulating liquids