Papers by gharsallah mohamed
2011 XXXth URSI General Assembly and Scientific Symposium, 2011
A novel coupling scheme to cylindrical dielectric resonator antenna is proposed and investigated.... more A novel coupling scheme to cylindrical dielectric resonator antenna is proposed and investigated. In particular, coupling to the resonator is achieved by simple slot firstly and a stair slot secondly exited by a microstrip line. The objectives of this change are to maximize the coupling, increase the gain and miniaturize the structure antenna, achieve resonance at the desired frequency. An approximate and quick design approach is given followed by more accurate design and analysis using commercial software. The antenna was fabricated and tested. Measurements match well with simulation results..
Applied Microbiology and Biotechnology, 2008
Medium composition and culture conditions for the bleaching stable alkaline protease production b... more Medium composition and culture conditions for the bleaching stable alkaline protease production by Aspergillus clavatus ES1 were optimized. Two statistical methods were used. Plackett–Burman design was applied to find the key ingredients and conditions for the best yield. Response surface methodology (RSM) including full factorial design was used to determine the optimal concentrations and conditions. Results indicated that Mirabilis jalapa tubers powder (MJTP), culture temperature, and initial medium pH had significant effects on the production. Under the proposed optimized conditions, the protease experimental yield (770.66 U/ml) closely matched the yield predicted by the statistical model (749.94 U/ml) with R 2 = 0.98. The optimum operating conditions obtained from the RSM were MJTP concentration of 10 g/l, pH 8.0, and temperature of 30 °C, Sardinella heads and viscera flour (SHVF) and other salts were used at low level. The medium optimization contributed an about 14.0-fold higher yield than that of the unoptimized medium (starch 5 g/l, yeast extract 2 g/l, temperature 30 °C, and pH 6.0; 56 U/ml). More interestingly, the optimization was carried out with the by-product sources, which may result in cost–effective production of alkaline protease by the strain.
IEEE Transactions on Microwave Theory and Techniques, 2011
This paper proposes a novel behavioral model for multiple-input single-output (MISO) and multiple... more This paper proposes a novel behavioral model for multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) nonlinear transmitters based on multivariable polynomials (MVPs). The main source of nonlinearity in these transmitters is the RF power amplifier, which is commonly modeled using polynomial models. The proposed MVP model is capable of handling the nonlinear effects of the RF transmitters, as well as the linear and nonlinear crosstalk between the input signals. At the same time, the developed model was optimized for computing efficiency without compromising its accuracy. The model was tested for MISO and MIMO wireless transmitters. The simulations and measurement results revealed that the proposed model gives excellent accuracy when modeling MIMO transmitters with different branch coupling factors.
Revue De Medecine Interne, 2005
A novel coupling scheme to cylindrical dielectric resonator antenna is proposed and investigated.... more A novel coupling scheme to cylindrical dielectric resonator antenna is proposed and investigated. In particular, coupling to the resonator is achieved by simple slot firstly and a stair slot secondly exited by a microstrip line. The objectives of this change are to maximize the coupling, increase the gain and miniaturize the structure antenna, achieve resonance at the desired frequency. An approximate and quick design approach is given followed by more accurate design and analysis using commercial software. The antenna was fabricated and tested. Measurements match well with simulation results.
Annales De Cardiologie Et D Angeiologie, 2006
... Lakhdahr et al. [8] rapportent même le cas d'un myxome géant de l'oreillette droite... more ... Lakhdahr et al. [8] rapportent même le cas d'un myxome géant de l'oreillette droite révélé par un trouble de l'humeur ayant amené la patiente à consulter en psychiatrie. Ces signes sont communs à tous les myxomes, ils sont souvent à l'origine du retard diagnostic. ...
Journal of Phytopathology, 2006
The full-length genome of a Tunisian isolate of Tomato yellow leaf curl Sardinia virus (TYLCSV) w... more The full-length genome of a Tunisian isolate of Tomato yellow leaf curl Sardinia virus (TYLCSV) was engineered and submitted to sequence analysis. The Tunisian isolate has 99% sequence identity with TYLCSV-Sicilian (Sic), results thus providing further evidence for the inclusion of this isolate in the TYLCSV-Sic group. A 1.7-mer construct of the virus was obtained and efficiently agroinfiltrated into tomato and tobacco plants to induce symptoms indistinguishable from those of natural infection.
A multiplex PCR method was developed to identify simultaneously either single or multiple infecti... more A multiplex PCR method was developed to identify simultaneously either single or multiple infections with members of the Tomato yellow leaf curl virus (TYLCV) complex. Several sets of species-specific primers, designed from sequenced genomes of TYLCV from the Mediterranean region (Sicily, Israel and Spain), were tested using plants infected with Egyptian and Tunisian isolates. The results show that this multiplex PCR is rapid, simple and a useful alternative to conventional tools such as PCR-RFLP or PCR-sequencing for typing virus isolates. Furthermore, this approach revealed evidence of recombination among Tunisian TYLCV genomes.
In this paper, we intend to study the synthesis of the linear antenna arrays. The synthesis imple... more In this paper, we intend to study the synthesis of the linear antenna arrays. The synthesis implementation's method for these type of arrays permits to approach the appropriated radiance's diagram. The used approach is based on neural network that are capable to model the linear antenna arrays, consider predetermined general criterias, and finally it permits to predict the appropriated diagram from the neural model. Our main contribution in this paper is the extension of a synthesis model of these arrays' radiance diagrams
Process Biochemistry, 2007
The thermoalkaline protease enzyme from pitaya (Hylocereus polyrhizus) waste was purified by a fa... more The thermoalkaline protease enzyme from pitaya (Hylocereus polyrhizus) waste was purified by a factor of 221.2 with 71.3% recovery using ammonium sulphate precipitation, gel filtration, and cation exchange chromatography. Gel filtration chromatography together with sodium dodecyl sulphate gel electrophoresis (SDS-PAGE) revealed that the enzyme is monomeric with a molecular weight of 26.7 kDa. The apparent and max of the protease were 2.8 mg/mL and 31.20 u/min, respectively. The optimum pH and temperature were 8.0 and 70 ∘ C. The enzyme was highly active and stable over a wide pH range (from pH 3.0 to pH 11.0 with the optimum activity at pH 8.0). The protease has broad specificity toward azocasein, casein, hemoglobin, and gelatine. Activity of the enzyme was inhibited by Fe 2+ and Zn 2+ , while protease activity was increased in the presence of Ca 2+ and Mg 2+ and Cu 2+ by factors of 125%, 110%, and 105%, respectively. The alkaline protease showed extreme stability toward surfactants and oxidizing agent. The purified protease exhibited extreme stability in the presence of organic solvents and inhibitors. In addition, the enzyme was relativity stable toward organic solvents and chelating agents, such as ethylenediaminetetraacetic acid (EDTA). The enzyme, derived from pitaya peel, possesses unique characteristics and could be used in various industrial and biotechnological applications.
Bioresource Technology, 2010
The physico-chemical and microbiological characterizations of olive mill wastewater sludge (OMWS)... more The physico-chemical and microbiological characterizations of olive mill wastewater sludge (OMWS) were investigated in five OMW evaporation ponds of the open-pond system in Sfax (Tunisia), during the olive oil production period in 2004. Time-dependent changes in both physico-chemical parameters and the microbiota were investigated. Mathematical models and principal component analysis (PCA) were used to establish the correlations between the studied parameters. During the effluent time-dependent changes in the ponds, the result of OMWS analysis showed an increase of sludge index (SI), ash content, total solids (TS), volatile solids (VS), ethyl acetate extractive (EAE) and total phosphorus (Total P), as well as microbial flora especially the yeasts and moulds. The SI, TS, VS and Total P changes with time fit a simple linear equation, while EAE, phenols and NH(4)(+) fit a second-degree polynomial model. The PCA analysis exhibited three correlated groups. The first group included temperature, ash content, evaporation, SI, TS, VS, Total P, EAE, yeasts and moulds. The second group was made by bacteria and moisture; and the third group by NH(4)(+), oil and phenol. Such modelling might be of help in the prediction of OMW changes in natural evaporation ponds.
Uploads
Papers by gharsallah mohamed