Optimum Sizing Algorithm for an Off Grid Plant Considering Renewable Potentials and Load Profile

The energy demand in remote area cannot be satisfied unless renewable energy based plants are locally installed. In order to be efficient, such projects should be sized on the basis of maximizing the renewable energies exploitation and meeting the consumer needs. The aim of this work is to provide an algorithm-based calculation of the optimum sizing of a standalone hybrid plant composed of a wind generator, a photovoltaic panel, a lead acid-battery bank, and a water tank. The strategy consists of evaluating the renewable potentials (solar and wind). Obtained results are entered as inputs to established generators models in order to estimate the renewable generations. The developed optimal sizing algorithm which is based on iterative approach, computes plant components sizes for which load profile meet estimated renewable generations. The approach validation is conducted for A PV/Wind/Battery based farm located in Sfax, Tunisia. Obtained results proved that the energetic need is covered and only about 4% of the generated energy is not used. Also a cost investigation confirmed that the plant becomes profitable ten years after installation.Article History: Received June 24th 2017; Received in revised form September 26th 2017; Accepted Sept 30th 2017; Available onlineCitation: Brahmi, N., Charfi, S., and Chaabene, M. (2017) Optimum Sizing Algorithm for an off grid plant considering renewable potentials and load profile. Int. Journal of Renewable Energy Development, 6(3), 213-224.https://doi.org/10.14710/ijred.6.3.213-22

Isolation and identification of bacterial strain I33M producing milk-clotting enzyme: Optimization of culture parameters using response surface

A strain I33M which produces a milk-clotting enzyme was screened from Algerian soil near a dairy factory. This strain was identified as Bacillus mojavensis based on morphology and internal transcription spacer sequence. Sequencing analysis of 16S rDNA gene showed 100% identity of the tested strain with the B. mojavensis in the database. Phylogenetic analysis of this strain showed that it was most closely related to Bacillus subtilis strain. The optimum levels of these significant parameters to obtain the highest milk clotting activity and the lowest proteolytic activity were determined employing the response surface methodology (RSM), which revealed these as follows: wheat bran 7%, casein 0.094%, temperature 39°C, agitation size (rpm) 150. Among the various variables screened, agitation and temperature were most significant in submerged fermentation (SmF). The optimal value of milk clotting activity (MCA) is esteemed at 2.40. Key words: Milk clotting protease, Bacillus, response surface methodology, sequencing analysis

Carbon Sequestration Potential of Pasture-Based Systems Along an Altitudinal Gradient in the North-Western Himalayas

The present investigation was carried out in the Chamba district of Himachal Pradesh (India) to identify the pasture-based land use systems being practiced by farmers and to find out their carbon sequestration potential along different altitudes. For carrying out the study, the area was divided into four altitudinal ranges viz., zone-I (\u3c1000 m amsl), zone-II (1000-1500 m amsl), zone-III (1500- 2500 m amsl) and zone-IV (\u3e 2500 m amsl), according to agro-ecological zones in the state. Results revealed that the pasture-based systems practiced by the farmers in the altitudinal zone-I and zone-II were silvo-pasture and pastoral-silviculture, while, at altitudinal zone-III and zone-IV, the pasture-based systems being practiced were pastoral-silviculture and horti-pastoral depending upon the composition of the components. The aboveground biomass was found ranging between 27.78- 38.18 Mg ha-1 among different pasture-based land use systems with maximum aboveground biomass under silvo-pasture system and minimum under pastoral-silviculture. Along altitudinal gradient, aboveground biomass was found to have been increased with values varying between 29.09- 34.12 Mg ha-1 . Belowground biomass ranged between 6.93- 9.80 Mg ha-1 in different systems under consideration and generally showed increasing trend with increasing altitude. Overall biological productivity was found to be highest under silvo-pasture system followed by horti-pastoral and pastoral-silviculture system. Being biologically most productive, silvopasture system stored maximum carbon stock and ultimately sequestered more carbon as compared to the other systems. The estimated vegetation carbon sequestration potential of the pasture-based systems was 63.71- 88.06 Mg ha-1 , while, along altitude the carbon sequestration potential varied from 67.14- 78.62 Mg ha-1 showing increasing trend with altitude

Empirical equations for the estimation of natural mortality in Mediterranean teleosts

Empirical relationships were established linking estimates of the instantaneous rate of natural mortality (M), the von Bertalanffy growth parameters, L sub( infinity ) (or W sub( infinity )) and K, and annual mean water temperature in 56 stocks of Mediterranean teleosts fish. It is suggested that these relationships generate for these fish more reliable estimates of M than the widely-used model of Pauly (1980, J. Cons. CIEM 33(3):175-192), which was based on 175 fish stocks, but included only five stocks from the Mediterranean

A combined polar and Cartesian piecewise trajectory generation and analysis of a robotic arm

In this paper a combined polar-Cartesian approach to generate a smooth trajectory of a robotic arm along priori defined via-points is presented. Due to the characteristics/- geometry of the robotic arm, cylindrical coordinates are associated with the trajectory of motion. Possible trajectories representing the system dynamics are generated by mix matching higher order polar piecewise polynomials used to devise the radial trajectory and Cartesian piecewise polynomials used to calculate the related height in a normal plane unfolded along the radial trajectory of the motion. To describe the kinematic properties of the end-effector a moving non-inertial orthonormal Frenet frame is considered. Using the Frenet frame, the components of the velocity and acceleration along the frame unit vectors are calculated. Numerical simulations are performed for two different configurations in order to validate the approach

Optical and photoelectronic properties of a new material:Optoelectronic application

With the aim of studying the optical, electrochemical, and electronic properties of a new porphyrin-based material, we have synthesized a new porphyrinic complex, namely the (4,4$^{\prime}$-bipyridine)(meso-tetratrifluoromethylphenylporphyrinato)zinc(II) 4,4$^{\prime}$-bipyridine disolvate dihydrate complex with the formula [Zn(TFMPP)(4,4$^{\prime}$-bipy)]${\cdot }$2(4,4$^{\prime}$-bipy)${\cdot }$2H2O (I). This species is characterized by single-crystal X-ray molecular structure. The optical study is performed by UV–visible absorption and fluorescence spectroscopy. The fluorescence intensity presents an emission in the UV–visible range, indicating that this compound can be used as an optoelectronic material. The optical energy gap is 1.95 eV, and the current–voltage characteristics and impedance spectroscopy measurements have been studied to define the electronic properties of the zinc (II) porphyrin complex. The barrier height ${\phi }_{\mathrm{b}}$ is calculated, and the space-charge limited current mechanism is found to control the conductance. The results from the electronic study confirm that our porphyrin derivative can be used for various optoelectronic applications

Empirical equations for the estimation of natural mortality in Mediterranean teleosts

Natural mortality, Statistical analysis, Mediterranean Region, Teleostei

Blind Separation of Cyclostationary Sources Sharing Common Cyclic Frequencies Using Joint Diagonalization Algorithm

We propose a new method for blind source separation of cyclostationary sources, whose cyclic frequencies are unknown and may share one or more common cyclic frequencies. The suggested method exploits the cyclic correlation function of observation signals to compose a set of matrices which has a particular algebraic structure. The aforesaid matrices are automatically selected by proposing two new criteria. Then, they are jointly diagonalized so as to estimate the mixing matrix and retrieve the source signals as a consequence. The nonunitary joint diagonalization (NU-JD) is ensured by Broyden-Fletcher-Goldfarb-Shanno (BFGS) method which is the most commonly used update strategy for implementing a quasi-Newton technique. The efficiency of the method is illustrated by numerical simulations in digital communications context, which show good performances comparing to other stateof-the-art methods