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Super capacitor energy storages have very high power density and low energy density in comparison with battery energy storages. In this case, it is impartment to well configure the super capacitor energy storage as peak power unit in each particular application (e.g. hybrid electric vehicle). Therefore, the simple and accurate model of super capacitors is required. In this paper, the methods of identifying and modeling their electrical characteristics are presented. Based on the detected parameters, the modeling of super capacitors is evaluated both in simulation system and in the test setup of a dedicated passenger car in ECE15 cycle.

Weather and climate extremes such its droughts and floods have far reaching impacts in Kenya. They have had implications on a variety of sectors including, agriculture, water resources, health, energy and disaster management among others. Lake Victoria and its catchment support millions of people and any impact onl its ability to support the livelihood of the communities in this region is of major concern. Thus, the main objective of this study was to assess the potential future climatic changes in the Nzoia catchment in the Lake Victoria basin and how they might affect streamflow The Soil and Water Assessment Tool was used to investigate the impact of climatic change on streamflow of the study area. The model was set up using readily available spatial and temporal data and calibrated against measured daily streamflow. Climate change. scenarios were obtained from general circulation models Results obtained showed increased amounts of annual rainfall for all the scenarios but with variations on a monthly basis. All - but 1 - global circulation models (GCMS) showed consistency in the monthly rainfall amounts. The analysis revealed important rainfall-runoff linear relationships for certain months that could be extrapolated to estimate amounts of streamflow under various scenarios of change in rainfall. Streamflow response was not sensitive to changes in temperature. If all other variables e.g. land cover, population growth etc, were held constant. a significant increase in streamflow may be expected in the coming decades as a consequence of increased rainfall amounts.

The specific technical challenges associated with the design of an ambient energy powered electronic system currently requires thorough knowledge of the environment of deployment, energy harvester characteristics and power path management. In this work, a novel flexible model for ambient energy harvesters is presented that allows decoupling of the harvester’s physical principles and electrical behavior using a three dimensional function. The model can be adapted to all existing harvesters, resulting in a design methodology for generic ambient energy powered systems using the presented model. Concrete examples are included to demonstrate the versatility of the presented design in the development of electronic appliances on system level.

Abstract The integration of distributed generation (DG) units into traditional distribution grids causes several significant changes in their characteristics like power flow direction, voltage profile and short circuit level. Therefore, the currently used control and protection strategies can no longer work properly and have to be revised and modified. The most important protection problems are e.g. blinding of protection, false tripping, unsynchronized reclosing. For a reliable and efficient protection system, both transient and steady states of fault current contributions should be considered. In this paper, in order to study the real impact of DG units on a given protection scheme, the fault current contributions generated with exact models of DG units including their interfaces with the grid and control system (photovoltaic generator, PSMG with full size converter, DFIG with partial size converter, commonly met on Belgian grids, and directly connected IG) are presented and compared with the ones that are generated by ideal models of DGs in the same conditions. The PSCAD software is used for the simulation of transient contributions of DGs under several faulty conditions in a tested medium voltage distribution grid.

Abstract Parameters such as heat transfer, arrangement type, covering and deviation from tilt angle of PV cells located on the wings of a solar-powered aircraft impact on the efficiency, power, flight duration and costs of the solar flyer. The objective of this paper is to represent these parameters and their influence on the efficiency and power to be considered before constructing. Related equations for design process and selecting PV cells are represented and discussed. Solar irradiance is not monotonic during the flight. Hence, components and algorithms for designing a MPPT (Maximum Power Point Tracker) device from perspective of being utilized in solar-powered aircrafts are investigated. Furthermore, heat transfer on the cells of the wings and its influence on the efficiency is discussed which can help to make up the power reduction caused by covering and deviation from tilt angle of the cells.

Yeasts are truly fascinating microorganisms. Due to their diverse and dynamic activities, they have been used for the production of many interesting products, such as beer, wine, bread, biofuels, and biopharmaceuticals. Saccharomyces cerevisiae (brewers’ or bakers’ yeast) is the yeast species that is surely the most exploited by man. Saccharomyces is a top choice organism for industrial applications, although its use for producing beer dates back to at least the 6th millennium BC. Bakers’ yeast has been a cornerstone of modern biotechnology, enabling the development of efficient production processes. Today, diverse yeast species are explored for industrial applications. This Special Issue is focused on some recent developments of yeast biotechnology, i.e., bioethanol, wine and beer, and enzyme production. Additionally, the new field of yeast nanobiotechnology is introduced and reviewed.

Abstract Co-utilization of fossil fuels and biomass is a successful way to make efficient use of biomass for power production. When replacing only a limited amount of fossil fuel by biomass, measurements of net output power and input fuel rates will however not suffice to accurately determine the marginal efficiency of the newly introduced alternative fuel. The present paper therefore proposes a technique to determine the marginal biomass efficiency with more accuracy. The process simulation model for co-utilization of natural gas and a small perturbing fraction of biomass in an existing combined cycle plant (500 MW th Drogenbos, Belgium) is taken as case study. In this particular plant, biomass is introduced into the cycle as fuel for a primary steam reforming process of the input natural gas. This paper proposes a perturbation analysis that has been developed to allow for an accurate assessment of the marginal efficiency of biomass by using only accurately measurable variables. To achieve this, effects of co-utilization were studied in each component of the gas turbine down to its steam bottom cycle to identify the components most affected by the limited perturbing amount of biomass. The procedure is validated through process simulation, where accurate marginal efficiencies can be compared with the efficiency obtained from the perturbation analysis. A full off-design simulation is required to achieve this result. Through the use of process simulation, the accuracy of the mathematical model could be verified for each formula and each assumption. Compared to process simulation data, the model was found to accurately predict marginal efficiencies of the introduced biomass for biomass shares as low as 0.1%.

The paper discusses the latest advances in the technologies to produce lignocellulosic ethanol (adnvaced or 2nd Generation biofuel) and biorefining