Isolation of lactic acid bacteria from Lighvan cheese, a semihard cheese made from raw sheep milk in Iran

The lactic acid bacteria contributing to Lighvan cheese ripening during the different stages of production were investigated. Isolated strains from different culture media were identified phenotypically to species and subspecies level. In total, 413 strains were isolated from raw milk, 1-day-old cheese and fully ripened cheese. The most abundant species belonged to Enterococcus faecium (87 isolates), Lactococcus lactis ssp. lactis (68 isolates), Enterococcus faecalis (55 isolates) and Lactobacillus plantarum (48 isolates). E. faecium, Lc. lactis and Lb. plantarum were the predominantly isolated strains from ripened cheese. Therefore, they may contribute considerably to the aroma and flavour development of Lighvan cheese.     

EFFECT OF EMULSIFIERS AND FUNGAL α-AMYLASE ON RHEOLOGICAL CHARACTERISTICS OF WHEAT DOUGH AND QUALITY OF FLAT BREAD

Teftoon, a flat bread made of whole wheat flour, is prepared by hand sheeting of dough, followed by baking. Different emulsifiers, like lecithin, E471 (distilled monoglyceride) and E472 (diacetylated tartaric acid esters of mono- and digelycerid of fatty acids), were added to the flour at various levels ranging between 0.25 and 1.0% w/w, and it was observed that they improved the dough characteristics. Improvement in bread quality parameters, such as force to tear and sensory acceptability, were monitored. Fungal α -amylase was also incorporated into the flour at 5–20 g/100 kg flour basis alone and in combination with the emulsifier. The force required to tear the fresh bread was decreased with emulsifier and enzyme addition; however, E472 addition at 0.75% w/w of whole wheat flour gave the softest bread. The tear force of stored bread significantly increased with storage; however, bread containing E472 showed a less increase in tear force up to a period of 3 days. The sensory acceptability was found to be higher than that of the control bread for emulsifiers, and lower for enzyme at a concentration higher than 10 g/kg flour.

PRACTICAL APPLICATIONS

Flat bread is normally consumed fresh, but the staling phenomenon starts immediately after baking this kind of bread. Today, large-scale production and increased consumer demands for high-quality bread with long shelf life have created the need for functional food additives such as emulsifiers and α -amylase enzyme. Incorporation of emulsifiers and enzyme decreased the hardness of Taftoon bread. Emulsifiers and α -amylase enzyme enhanced the flat bread dough quality. The sensory acceptability also improved with the addition of emulsifiers. Optimizing the amount of emulsifiers and enzyme required for reduction of bread hardness is vital because the quality and price of the final product depend on this parameter.     

Technical cross-fertilization between terrestrial microgrids and ship power systems

Aspects of terrestrial microgrids and ship power systems are examined.The work exposes a variety of technical synergies from these two power systems to effectively advance their technologies.Understanding their overlap allows congruent efforts to target both systems;understanding their differences hinders conflict and redundancy in early-stage design.The paper concludes by highlighting how an understanding of both systems can reduce the investment in research resources.     

桥面板与覆层结合界面的干燥收缩诱导应力估算

采用三维非线性有限元分析方法评价与估算了桥面板与混凝七覆层间结合界面的干燥收缩诱导应力.并采用修正Fowler准则测算了桥面板与聚合物覆层间的热诱导应力.在评价覆层与面板问相对厚度to/ts的影响时,ts取常数200mm;在评价相对弹性模量Eo/Es的影响时,Es取常数,27.5GPa,并设定了3个Eo/Es比值,分别...     

Stress determination and geomechanical stability analysis of an oil well of Iran

In this paper, a numerical model using three-dimensional finite difference code FLAC3D is proposed for analysing the stability of an oil well drilled in four formations. Normalized Yielded Zone Area (NYZA, i.e., the ratio of surrounding yielded cross-sectional area to initial area of well) has been determined for different mud pressures. In each formation, by interpolating of obtained NYZA equal to one, the optimized mud pressure was determined using MATLAB software. Practical data including geomechanical parameters along with drilling data from one of Iranian oilfields, Mansouri-54 well have been utilized in this analysis. In situ stress was determined using stress polygon method and conducting hydraulic fracturing data in the field. Analytical solution using the Mogi–Coulomb and the Hoek–Brown failure criteria has been carried out and results are compared with the presented model. The results demonstrated that the NYZA and Hoek–Brown criteria might underestimate and overestimate the drilling mud pressure, respectively, and should be used cautiously. In the inclined section of the well, plastic zone showed more extension in the lower part than upper part of the well because of the high stress concentration.     

Allowable coefficient perturbations with preserved stability of a Hurwitz polynomial†

Given a polynomial P(s) = a_nsⁿ + a_n?11S^n?1 + … -+ a₁s + a₀ which satisfies the Routh-Hurwitz criterion, a procedure is given for finding non-conservative upper bounds on the allowable variations of the coefficients such that the perturbed polynomial maintains the stability property.     

Electrical conduction in anodic tungsten oxide thin films

Thin films of tungsten oxide were prepared by anodic oxidation of 99.999% pure tungsten foils using an aqueous solution containing 0.4 M KNO₃ and 0.04 M HNO₃ as the electrolyte. Different films show different colours. The current-voltage characteristics are of the log I- V^1/2 type. These characteristics can be interpreted in terms of the Poole—Frenkel type of conduction mechanism. The colours may be duo to the incorporation of H⁺ ions and the formation of HxWO₃ during the anodizing process.     

The effect of adding enzyme‐modified cheese on sensory and texture properties of low‐ and high‐fat cream cheeses

The influence of enzyme‐modified cheese (EMC) and fat content on sensory and texture properties of cream cheese was investigated. Enzyme‐modified cheese and fat content were set at three levels each, and organoleptic and texture properties for all experimental cheeses were then determined. Data were analysed using response surface methodology. Both design parameters had significant influence on sensory and texture properties. The EMC did not alter hardness significantly, whereas the higher fat formula had the higher hardness. The results indicated that the optimum level of EMC was less than 1% for high‐fat cream cheeses and at least 5% for low‐fat cream cheeses.