CHARACTERIZATION OF AEROMONAS SPECIES ISOLATED FROM FOOD

Characterization of ten Aeromonas spp. isolates from local foods and A. hydrophila ATCC 7965, revealed that all strains of A. hydrophila, A. sobria and one strain of A. caviae showed strong hemolytic activity. All of them were protease producers except one A. caviae strain. Some A. hydrophila and A. caviae strains fermented lactose, coagulated milk and reduced litmus. The majority of strains were resistant to at least 5 of 14 antibiotics tested. All the strains grew over the range of 5–42C except those of A. caviae which failed to grow at 42C. Frozen storage at -16C greatly decreased the viability of the tested strains. Radiation D₁₀values of strains ranged from 0.109–0.253 kGy in nutrient broth and increased when some strains were irradiated in ground meat at room temperature. Both strains of A. hydrophila ( ATCC andFI ), A. sobria FI and A. caviae FI grew normally in the presence of 1 and 3% salt. Only A. hydrophila FI tolerated 6.5% salt. These four strains were able to grow in the presence of 0.05–0.3% potassium sorbate at pH 7.0, while at pH 5.0 the presence of sorbate prevented their growth .     

Effects of Microwave Heating and Gamma Irradiation on Phytate and Phospholipid Contents of Soybean (Glycine max. L.)

The effect of microwave heating and gamma irradiation treatments on phosphorus compounds of soybean seeds were studied. Inorganic phosphorus was significantly (P < 0.05) increased while, phytate and phospholipids were significantly decreased when soybean seeds were microwave-heated for 9 min or more. Furthermore, gamma-irradiation treatments of 20 KGy or more significantly increased inorganic phosphorus and decreased phytate and phospholipids of the beans. Two dimensional thin-layer chromatography was employed to study the phospholipid pattern. Gamma-irradiation at doses from 40 to 100 KGy produced lysophosphatidylcholine and phosphatidic acid. The data of this study showed that, the increase of inorganic phosphorus was mainly due to the decomposition of phytic acids and phosphates of inositol.     

Effects of Experimental Cooking on the Yield and Proximate Composition of Three Selected Legumes

Dry mature seeds of field pea (Pisum arvense), moth bean (Vigna aconitifolia) and pigeon pea (Cajanus cajan) were investigated for their chemical and cooking characteristics. The crude protein (N × 6.25) content was 24.5% for field pea (8.5% moisture basis), 22.7% for moth beans (10% moisture basis) and 21.3% for pigeon pea (10% moisture basis). Ratios of cooked weight/dry weight after cooking the whole and dehulled seeds were 2.14 and 2.18, 2.20 and 2.30, and 2.43 and 2.51 for the field pea, moth bean and pigeon pea, respectively. Dehulling increased the protein, fat and energy contents but decreased the ash and fiber contents as well as cooking times. On cooking, the true retentions of proximate principles were good.     

NON DESTRUCTIVE DIELECTRIC CHARACTERIZATION OF THIN FERROELECTRIC FILMS MATERIALS USING COPLANAR LINE STRUCTURE

ABSTRACT

This paper presents a nouvelle and non-destructive Broadband characterization method which uses a coplanar line for the measurement of the complex permittivity of linear dielectric materials and precisely, that of ferroelectric thin films. The method uses the transmission coefficient and the quasi-TEM analysis to find the effective permittivity of the multilayer system, and then the coplanar conformal mapping technique is employed to extract the relative permittivity of the thin layer. Comparing our results to those of cavity resonator method at 12 GHz shows a good agreement. The measurement is done in the microwave frequency band (45 MHz–20 GHz).     

Construction of optimal feedback control for nonlinear systems via Chebyshev polynomials

A method is proposed to determine the optimal feedback control law of a class of nonlinear optimal control problems. The method is based on two steps. The first step is to determine the open-hop optimal control and trajectories, by using the quasilinearization and the state variables parametrization via Chebyshev polynomials of the first type. Therefore the nonlinear optimal control problem is replaced by a sequence of small quadratic programming problems which can easily be solved. The second step is to use the results of the last quasilinearization iteration, when an acceptable convergence error is achieved, to obtain the optimal feedback control law. To this end, the matrix Riccati equation and another n linear differential equations are solved using the Chebyshev polynomials of the first type. Moreover, the differentiation operational matrix of Chebyshev polynomials is introduced. To show the effectiveness of the proposed method, the simulation results of a nonlinear optimal control problem are shown.     

Application of Large Bore Coated (LBC) Columns to Flavor Analysis of Beverages and Confections

A large bore coated (LBC) column consisting of 25 ft ×¼ in. o.d. aluminum tubing internally coated with silicone rubber can extract flavors from beverages and dissolved confections. The beverage or solution is simply poured through the column. The column is washed with water, dried with nitrogen, and the trapped organics transferred with heat and nitrogen to a porous polymer pre-column sized to fit the tube oven attached to the injector of the gas chromatograph. A model system of peppermint oil at 2.5 ppm in water showed that quantitative recovery of components in the ppb range was possible. Recovery factors were investigated, revealing interference from colloidal systems as in milk and beer. The LBC column method for flavors in carbonated beverages was compared with solvent extraction and nitrogen sparging methods. Results were comparable.     

ANTIMUTAGENIC ACTIVITIES OF PHENOLIC PLANT FLAVONOIDS

Total phenolic plant flavonoids obtained from Thuia accidentalis L. and Cupressus sempevirens L. showed antimutagenic effects on benzo(a) pyrene [B(a)P] in Salmonella typhimurium strains TA100 and TA98. The n-butanol extract was more effective then chloroform and petrol eum-ether extracts, respectively. Aqueous extracts exhibited no inhibition in both strains. Total flavonoids from C. sempevirens showed more antimutagenic activity than flavonoids from T. accidentalis. None of the extracts revealed any cytotoxic or mutagenic activity on the bacterial tester strains.     

A comparative study on the use of drilling and milling processes in hole making of GFRP composite

Drilling and milling processes are extensively used for producing riveted and bolted joints during the assembly operations of composite laminates with other components. Hole making in glass fibre reinforced plastic (GFRP) composites is the most common mechanical process, which is used to join them to other metallic structures. Bolt joining effectiveness depends, critically, on the quality of the holes. The quality of machined holes in GFRP is strongly dependent on the appropriate choice of the cutting parameters. The main purpose of the present study is to assess the influence of drilling and milling machining parameters on hole making process of woven laminated GFRP material. A statistical approach is used to understand the effects of the control parameters on the response variables. Analysis of variance (ANOVA) was performed to isolate the effects of the parameters affecting the hole making in the two types of cutting processes. The results showed that milling process is more suitable than drilling process at high level of cutting speed and low level of feed rate, when the cutting quality (minimum surface roughness, minimum difference between upper and lower diameter) is of critical importance in the manufacturing industry, especially for precision assembly operation.     

STABILITY AND RHEOLOGY OF HEAVY CRUDE OIL-IN-WATER EMULSION STABILIZED BY AN ANIONIC- NONIONIC SURFACTANT MIXTURE

ABSTRACT

The stability and rheology of an Egyptian Heavy crude oil-in-water emulsions stabilized by an anionic (TDS) and a nonionic (NPE) surfactants individually or in a mixture have been studied. The study reveals that, the viscosity of the crude oil decreases when it is emulsified with water in the form of an oil-in-water type of emulsion. The stability of the oil-in-water emulsion increases as the surfactant concentration and speed of mixing of the emulsion increases. Fresh water and synthetic formation water have been used to study the effect of aqueous phase salinity on the stability and viscosity of the emulsion. Surfactant dissolved in synthetic formation water has been utilized to find out the possibility of injecting the surfactant into a well bore to effect emulsification in the pump or tubing for enhancing the production of heavy crude oils as oil-in-water emulsion. The study revealed that, the viscosity of the emulsion containing fresh water is always less than that containing formation water, these findings have been correlated with the crude oil/water interracial tension (IFT) measurements The decreased IFT value results in a decrease in the average particle size of the dispersed crude oil leading