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Global environmental concerns and rapidly increase demands for energy, coupled with permanent progress in renewable energy technologies, are creating new opportunities to utilize renewable energy resources. Solar energy is the most abundant, inexhaustible and clean of all the renewable energy resources. Photovoltaics generate electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Building integrated photovoltaics (BIPV) are photovoltaic materials that are used to replace conventional building materials in parts of the building envelopes, such as the roofs, skylights or facades. There are several advantages of integrated photovoltaics over more common non-integrated systems which make BIPV one of the fastest growing segments of the photovoltaic industry. Building integrated photovoltaic (BIPV) systems may represent a powerful tool for achieving the ever increasing demand for zero energy and zero emission buildings of the near future.

It is well known that nowadays a significant part of the total energy consumption is related to buildings, so research for improving building energy efficiency is very important. This paper presents our investigations about the dimensioning of horizontal overhangs in order to determine the minimum annual consumption of building primary energy for heating, cooling and lighting. In this investigation, embodied energy for horizontal roof overhangs was taken into account. The annual simulation was carried out for a residential building located in the city of Belgrade (Serbia). Horizontal overhangs (roof and balcony) are positioned to provide shading of all exterior of the building. The building is simulated in the EnergyPlus software environment. The optimization of the overhang size was performed by using the Hooke Jeeves algorithm and plug-in GenOpt program. The objective function minimizes the annual consumption of primary energy for heating, cooling and lighting of the building and energy spent to build overhangs. The simulation results show that the building with optimally sized roof and balcony overhangs consumed 7.12% lessprimary energy for heating, cooling and lighting, compared to the house without overhangs. A 44.15% reduction in cooling energy consumption is also achieved.

Deterministic and stochastic models of Brownian motion in ferrofluids are of interest to researchers, especially those related to drug delivery systems. The Brownian motion of nanoparticles in a ferrofluid environment was theoretically analyzed in this research. The state of the art in clinical drug delivery systems using ferromagnetic particles is briefly presented. The motion of the nanoparticles in an external field and as a random variable is elaborated by presenting a theoretical model. We analyzed the theoretical model and performed computer simulation by using Maple software. We used simple low-dimensional deterministic systems that can exhibit diffusive behavior. The ferrofluid in the gravitational field without the presence of an external magnetic field in the xy plane was observed. Control parameter p was mapped as related to the fluid viscosity. Computer simulation showed that nanoparticles can exhibit deterministic patterns in a chaotic model for certain values of the control parameter p. Linear motion of the particles was observed for certain values of the parameter p, and for other values of p, the particles move randomly without any rule. Based on our numerical simulation, it can be concluded that the motion of nanoparticles could be controlled by inherent material properties and properties of the surrounding media, meaning that the delivery of drugs could possibly be executed by a ferrofluid without an exogenous power propulsion strategy. However, further studies are still needed.

Useful tool in diagnostic radiology is magnetic resonance imaging (MRI). Scanning with this system can cause interaction between ferromagnetic used for creation of implants and magnetic fields of MRI. In order to determine magnetic field distribution the integral equation governing magnetic scalar potential is formed with induced magnetic charges on the thin arbitrary shaped ferromagnetic plate as unknowns. The obtained integral equations will be numerically solved using Equivalent electrodes method. Application of ferromagnetic materials in biomedical implants will be observed. Also, possible risk of interaction of these implants and MRI devices is analyzed.

For a positive net building (PNEB), the paper presents its need, and tools to achieve its design. The PNEB should provide the maximum thermal comfort with a minimum of energy, primary energy, and exergy consumption, .and reduction of the use of energy resources, maximizing energy security, as well as the minimum impact on the environment. This very useful knowledge is also needed for identifying energy efficiency, as well as for dictating the right energy management strategies of a country. Then, the paper presents the software for a energy simulation and optimization of PNEB. After that, the paper describes the three examples connected to the PNEB. The first example is a simulation of a residential PNEB in Serbian conditions, second the optimization of photovoltaics panels area at Serbian zero-net energy building, third the description of an the building and optimizing energy performances, by placing the solar collector in the optimum position.

One of the main tasks of CT scanner design is to obtain enough quality of image and to reduce effective dose of X - ray radiation. These are inconsistent requirements because reducing of effective dose in the same time can degrade the image quality. The fact that can be used to reduce the dose while preserving the image quality is that different tissues absorb X-photons of different energy which allow us to make specific scanning procedures depending on the type of tissue being examined. This scenario includes use of different filter types, which change the X-ray spectra produced by the X –ray tube. In this paper two types of tissues are considered soft and cortical bone tissue. For X ray spectra simulation the SpekCalc software is used. This approach can be very helpful for medical doctor to reduce total effective dose during scanning procedure.

Life Cycle Assessment (LCA) represents the most widely adopted tool for calculation and evaluation of the environmentally relevant inputs and outputs and the potential environmental impacts of the life cycle of a product, material or service. But, LCA methodology has its own disadvantages: it assesses environmental sustainability impacts and neglects the social and economic aspect of sustainability. Over the past decade, LCA has improved to include life cycle costing (LCC) and social LCA (SLCA), drawing on the 'triple bottom line' model of sustainability. With these developments, LCA has broadened from merely environmental assessment to a more comprehensive life cycle sustainability assessment. This paper presents the concepts and methodologies for developing the sustainability method based on life cycle thinking, including a description of a new method called Life Cycle Sustainability Assessment (LCSA). It was described the concept of sustainability, with three pillars of sustainability, i.e. the environmental, economic and social dimensions, which is the basement of LCSA methodology. After that the indicators were presented, as a ways of measuring impacts which indicate changes away from an original or a wanted condition.

According to the contemporary epidemiological researches, there are some indications that extremely low frequency electromagnetic fields harm human health which has been proved through numerous scientific studies published in recent years. Today, most countries use the ICNIRP guidelines and Council Recommendation as the scientific basis for their recommended levels of exposure. Magnetic fields from high voltage transmission power lines have been discussed in this paper. The field profiles and their contribution to environmental pollution are studied. The obtained results are found to be useful for discussing the comparison of the field densities on the human body at the ground level under or near the lines.