This paper provides a preliminary analysis of the supercritical Brayton cycle, a power generation system for space exploration. Supercritical working fluids increase efficiency due to increased compressibility at the critical point but have not been investigated at the high temperatures necessary for space power generation. Through computer simulation, the viability of the supercritical Brayton...

Supercritical fluid extraction and quantification of chlorpyrifos insecticides in fresh vegetables by Gas Chromatography with Electron Capture Detection (GC-ECD) 1Mohammad Arifur Rahman*, 2Dzolkhifli Omar, 3Md Zaidul Islam, 2M.M.Morshed and 3K.N.H bin Rashid Toxicology lab., Horticulture Research Centre (HRC), Bangladesh Agricultural Research Institute (BARI), Gazipur-1701, Bangladesh. Departme...

In the past decade, supercritical fluid chromatography (SFC) has experienced a steady growth in acceptance, particularly in pharmaceutical and chemical laboratories. In SFC, a “supercritical” fluid, most commonly CO2, in combination with one or more polar organic solvents, such as alcohols, is used as mobile phase. Compared to HPLC, SFC offers better selectivity and shorter analysis time due to...

(1995) Journal of Chromatography A 691: 239}246. [43] LeBelle M, Pike RK, Graham SJ, Ormsby ED and Bogard H (1996) Journal of Pharmaceutical and Biomedical Analysis 14: 793}800. [44] Bernal JL, del Nozal MJ, Martin MT and Diez-Masa JC and Cifuentes (1998) Journal of Chromatography A 823: 423}431. [45] Polettini A, Bouland GM and Montagna M (1998) Journal of Chromatography B: Biomedical Sciences...

Since there is an enormous volume of information on the separation of antibiotics in the literature, readers should be able to Rnd HPLC conditions for almost any antibiotic of interest. Readers are also encouraged to consult the ofRcial compendia for analysis of bulk or formulated drugs. For analysis of biological samples, the samples may be directly injected with a column switching technique i...

Supercritical Suid chromatography (SFC) on a preparative scale is of interest because of its advantages over high performance liquid chromatography (HPLC). The high diffusivity and low viscosity of supercritical Suids allow rapid separation. The solvent strength can easily be controlled by changing pressure and/or temperature, so that mobile phases with a Rxed composition can be used to separat...

The basic unit operations in vegetable oil processing are shown in Figure 4. Oil is extracted from plant material (oilseeds) using a solvent, usually hexane. Published research indicates that about 50}70% of the hexane can be recovered and recycled using nanoRltration membranes instead of the evaporators used today, thus reducing energy consumption substantially. The extracted crude oil is most...