ASPEN systems

A. McRae and L. Whelchel, eds.. Toxic Substances Control Sourcebook, Aspen Systems Corporation, 1978, p. 124. 

Applebaum SH, Rohrs WF. 1981. Time Management for Health Care Professional. Rockville, MD Aspen Systems. 

A major limitation in many flowsheeting systems is the inability to handle electrolytes. New work in this area is now being reported ( 1, 42) and two commercial systems are available (43, 44TT The ASPEN system ( ) has incorporated a solids handling capability to overcome another common deficiency. 

The ASPEN system is on schedule for a working version to be completed October, 1979. The program system will be comprised of about 150,000 lines of FORTRAN code and data for physical... 

Another potential advancement is permitted in the ASPEN system. Tear streams can be designated as desired, so that a user might define blocks or series of blocks and simulate these sets as quasi-linear blocks. The convergence method could utilize this information and solve the material (and energy) balances explicitly. In this way, a simultaneous modular architecture could be utilized. Implementation of these programs will be for later enhancements of ASPEN, not the initial version. 

The ASPEN system does facilitate the inclusion of a user s own model either in FORTRAN source code or compiled into an object code. The proprietary model may rely on the entire physical property system to calculate the required properties, however, the user routines must have the correct interface calls. These are to be documented in the ASPEN user manual. 

A working version of ASPEN will be completed by October, 1979. A future phase of this project is anticipated for the testing of ASPEN and transferring the technology into the public domain. Industrial, government, and academic users will be able to access and use ASPEN in a controlled test environment. The ASPEN staff will maintain the system for testing, train and consult with users, and enhance the system. At the end of the test project a more proven, reliable ASPEN system will then be made available to the public. 

Akashah et al. optimum feed, 118.119 Albright random cells, 542 AMSYM program, 171,192 ASPEN system, 163 ASPENPlus system, 163, 177,179 187 192... 

Aspen Systems, Inc., 184 Cedar Hill Street, Marlborough, MA, 01752, USA. 

Moss, F.E., and Halamandaris, V.J. 1977. Too Old, Too Sick, Too Bad Nursing Homes in America. Germantown, MD Aspen Systems Corp. 

L. A. Karacoloff (1986), Lower Extremity Amputation, Aspen Systems Corporation, Rockville, Md. 

Turner, J. (ed.). Violence in the Medical Care Setting A Survival Guide. Rockville, MD Aspen Systems Corporation. 

Aspen Systems, (1999), Proc. of the USDOE CARAT Program Review, Troy (Michigan), Sept. 23. 

Mature phreatophyte trees (poplar, willow, cottonwood, aspen, ash, alder, eucalyptus, mesquite, bald cypress, birch, and river cedar) typically can transpire 3700 to 6167 m3 (3 to 5 acre-ft) of water per year. This is equivalent to about 2 to 3.8m3 (600 to 1000 gal) of water per tree per year for a mature species planted at a density of 600 trees per hectare (1500 trees per acre). Transpiration rates in the first two years would be somewhat less, about 0.75 m3 per tree per year (200 gal per tree per year), and hardwood trees would transpire about half the water of a phreatophyte. Two meters of water per year is a practical maximum for transpiration in a system with complete canopy coverage (a theoretical maximum would be 4 m/yr based on the solar energy supplied at latitude 40°N on a clear day). 

The non-random two-liquid segment activity coefficient model is a recent development of Chen and Song at Aspen Technology, Inc., [1], It is derived from the polymer NRTL model of Chen [26], which in turn is developed from the original NRTL model of Renon and Prausznitz [27]. The NRTL-SAC model is proposed in support of pharmaceutical and fine chemicals process and product design, for the qualitative tasks of solvent selection and the first approximation of phase equilibrium behavior in vapour liquid and liquid systems, where dissolved or solid phase pharmaceutical solutes are present. The application of NRTL-SAC is demonstrated here with a case study on the active pharmaceutical intermediate Cimetidine, and the design of a suitable crystallization process. 

This work was part of the Advanced System for Process Engineering Project (ASPEN) supported by the U.S. Department of Energy under contract number E(49-18)-2295, Task No. 9. 

Two ASPEN (Advanced System for Process Engineering, public version) simulations compare the performance of conventional and networked fuel cell systems having identical recycle schemes and steam bottoming cycles. Each simulated system was composed of three MCFC stacks operating at the same temperature and pressure. The Nemst potential of each MCFC in both systems was reduced by 0.3 volts due to activation, concentration and ohmic voltage... 

Three components extracted from the female glands of the large aspen tortrix, Choristoneura conflictana (Lepidoptera Tortricidae), elicited response from antennae of conspecific males using coupled GC-EAD system. The main component extracted from the glands was... 

Khogeer (2005) developed an LP model for multiple refinery coordination. He developed different scenarios to experiment with the effect of catastrophic failure and different environmental regulation changes on the refineries performance. This work was developed using commercial planning software (Aspen PIMS). In his study, there was no model representation of the refineries systems or clear simultaneous representation of optimization objective functions. Such an approach deprives the study of its generalities and limits the scope to a narrow application. Furthermore, no process integration or capacity expansions were considered. 

This is the fun (and frustration) of chemical reaction engineering. While thermodynamics, mass and heat transfer, and separations can be said to be finished subjects for many engineering apphcations, we have to reexamine every new reaction system from first principles. You can find data and construct process flowsheets for separation units using sophisticated computer programs such as ASPEN, but for the chemical reactors in a process these programs are not much help unless you give the program the kinetics or assume equihhrium yields. 

Figure 2A. Dual chromatograms showing the elution of aspen AESE lignin from the HPSEC-DV system. A 250 fiL sample was injected from a freshly prepared 8 mg /mL stock solution. Viscotek A/D amplifier gain setting of 2 and RI detector setting of lx. Calculated molecular weights are also shown.

Figure 4A. Dual chromatogram showing the elution of AESE aspen lignin from the HPSEC-DV system with an amplifier gain setting of 2 and an RI setting of l/4x. This experiment represents the minimum loading of such a sample which results in usable signal.

Figure 4B. Concentration chromatogram of three column loadings (1 mg, 0.2 mg, and 0.1 mg) of oganosolv aspen lignin on the HPSEC-DV system. RI detector setting was lx.

MH Locke, "The ASPEN PLUS Pressure Relief System Technical Details and Benchmark Results", Attachment 69 Minutes of 17th DIERS Users Group Meeting, Orlando, January 1995... 

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