Complex U is composed of orotate phosphoribosyltransferase (EC 2.4.2.10) and orotidine-5’-phosphate decarboxylase (EC 4.1.1.23), the last two enzymes of the de nouo pathway for pyrimidine biosynthesis. Since the two enzymes have proved inseparable so far, the equilibrium constant for the phosphoribosyltransferase activity has been determined under conditions where the decarboxylase activity was...

In the automotive industry, flow of air generates high resistance in advance vehicles. light this situation, objective present invention is to take advantage force itself help propel vehicles and thus reduce fuel consumption. A channeling system has been designed based on a deflector that collects impacts against vehicle at front, transferring it rear where expelled, allowing vacuum zone be fil...

Fractured carbonate reservoirs account for 25% of world’s total oil resources and for 90% of Iranian oil reserves. Since calcite and dolomite minerals are oil wet, gas oil gravity drainage (GOGD) is known as the most influencing production mechanism. The most important issue within gas injection into fractured media is the channeling problem which makes the efficiency of gas injection process e...

Forced displacement of oil by polymer flooding in oil reservoir is one of the effective methods of enhanced (tertiary) oil recovery. A classical model of this process within Hele-Shaw approximation involves three-layer fluid in a Hele-Shaw cell having a variable viscosity fluid in the intermediate layer between oil and water. The goal here is to find an optimal viscosity profile of the intermed...

Fluid mixing plays a fundamental role in many natural and engineered processes, including groundwater flows in porous media, enhanced oil recovery, and microfluidic lab-on-a-chip systems. Recent developments have explored the effect of viscosity contrast on mixing, suggesting that the unstable displacement of fluids with different viscosities, or viscous fingering, provides a powerful mechanism...

The extent to which carbon flux is directed toward fermentation versus respiration differs between cell types and environmental conditions. Understanding the basic cellular processes governing carbon flux is challenged by the complexity of the metabolic and regulatory networks. To reveal the genetic basis for natural diversity in channeling carbon flux, we applied quantitative trait loci analys...

An indicator of bypassing is a premature drop in gas-oil ratio; i.e., earlier than expected collapse of gas saturation. Early gas collapse (water fillup) may indicate that channeling has occurred. In layered reservoirs with no or little vertical crossflow, water injection in an initially depressurized layer will cause GOR to drop rapidly. Often naturally fractured reservoirs exhibit fast gas co...