Simultaneous Mode

The simultaneous mode is the simplest configuration where the feed streams of the endothermic mixture and the combustion gas are mixed and react 

7 Enhancing Productivity and Thermal Efficiency of High-Temperature Endothermic Processes 

In the asymmetric mode of operation the endothermic and exothermic reactions take place separately either in different compartments (recuperative mode) or at different time intervals (regenerative mode). The attractiveness of the asymmetric mode is related to the fact that the separation of the process streams allows an individual tuning of the operating conditions for the endothermic and the exothermic subsystem. 

The symmetric mode aims at combining the advantages of the simultaneous and the asymmetric mode only the endothermic reaction takes place in the main reactor. The process heat is added through a hot, inert side stream (e.g., the effluent gas of an external combustion chamber). The side stream can be distributed along the reactor in order to adjust a specific temperature profile. 

The counter-cocurrent concept features a modular design it provides separate heat exchanger loops for heat recovery within the endothermic mixture and the combustion gas. Cocurrent flow of exothermic and endothermic process streams is principally favorable with respect to the controllability of heat release. 

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Based on castor oil derived elastomers and crosslinked polystyrene, a simultaneous mode of polymerization can be successfully employed to synthesize prototype engineering materials such as tough, impact resistant plastics and reinforced elastomers. 

As indicated by this schematic representation, different configurations vary with respect to the degree of coupling between the process streams. The strongest coupling occurs in the simultaneous mode, where chemical and thermal interaction occurs between the process streams. In contrast to this, the counter-cocurrent concept features only thermal interaction between the process streams localized in the reactor stage. 

Electrothermal programs may differ widely depending on the elements so that it is impossible to use them in the simultaneous mode. 

The optimization model in the sequential case had 342 equations and 362 variables for the reactor flowsheet optimization (96 CPU seconds on the VAX 6320) and 200 equations and 161 variables for the energy integration (170 CPU seconds). The simultaneous optimization model (542 equations, 523 variables) was solved in 1455 CPU seconds and was initialized with the solution to the sequential model. Table I presents a comparison between the results for sequential and simultaneous modes to synthesis. A target production rate of 40,000 Ib/h is assumed for the desired product B. 

In this section, we reconsider the van de Vusse process to illustrate our synthesis approach. This example also shows the application of the unified reaction-separation-energy integration model. Comparisons are made between sequential and simultaneous modes of synthesis, and the applicability of the simplified model is verified. 

When there are multiple recycles present, it is sometimes more effective to solve the model in a simultaneous (equation-oriented) mode rather than in a sequential modular mode. If the simulation problem allows simultaneous solution of the equation set, this can be attempted. If the process is known to contain many recycles, then the designer should anticipate convergence problems and should select a process simulation program that can be run in a simultaneous mode. 

Foods, food, biological CRMs A1 As B Ba Cd Ca Cr Co Cu Fe Pb Mg Mn Mo Ni P k Se Na Sr T1 VZn Microwave digestion in closed vessel, dear, light yellow solutions pj DMCV] Applied Research Laboratories Model 3580 ICP-AESr in simultaneous mode [ICP-AES] [WDMCV-ICP-AES Dolan and Capar (2002)... 

Other research in the field of simultaneous dissolution has focused on the active dissolution of Fe—Cr alloys, which was shown to proceed in the simultaneous mode at quasi-steady state conditions [40]. Applying y-spectroscopic methods, Kolo-tyrkin [41] measured the partial anodic polarization curves of the components Fe and Cr and was able to show that the dissolution rate of Cr from the alloy is more decreased than would have been expected on the basis of its bulk mole fraction (that is, Cr becomes the slow-dissolving component), and the contrary is true for the dissolution of Fe. This implies an enrichment of the Cr in the corroding alloy surface that may promote its subsequent passivation [34]. Also, with increasing Cr concentration of the alloy, the Tafel slope of the partial polarization curves of the components was shown to change from values that are typical for pure Fe to values that are typical for pure Cr [40, 41]. It appears, therefore, that for Fe—Cr alloys, the dissolution of the alloy components occurs in an interdependent... 

Thermogravimetric analysis provides a quantitative measurement of the mass change, but does not indicate the nature of the material lost. Hence, it is often used in a combined manner with evolved gas analysis (EGA) measurements on the same sample. EGA determines the specific nature of the changes in the gas phase and may be done in a qualitative or quantitative manner. There are several modes of operation. Gas samples can be trapped and analyzed periodically either during or at the end of the experiment. More common and more useful is to monitor the atmosphere and correlate its chemical nature with the observed mass change in a near-simultaneous mode, with negligible delay between mass loss in the TGA and gas detection by EGA. 

By the way, when you read body language, you are using primarily the right side of your brain. Your brain s right side operates or thinks in a visual, perceptual, and simultaneous mode contrasted with your brain s left side which thinks in a verbal, analytic, and sequential mode (Edwards 1999). Refer to the Chapter 7 section titled Mind Mapping for additional discussion of how the brain s hemispheres function. 

In the case of a flow rate programming, it is of paramount importance to have consistency in the appearance and duration times, e.g., starting and ending times of the plug peaks should be reproducible. Lack of it should lead to corrupted results especially in those cases where cycling between the different scanning acquisitions is performed in subsequent periods and not in simultaneous mode (see rationale in the caption of Fig. 15). 

Fig. 11 Typical optical setup of a fast multidimensional microscope for fixed (left) and Uving (right) cell observation. For fixed-sample acquisition, image stacks are acquired sequentially, one color at a time. Single dichroic mirrors are used and exchanged to switch between colors. For Uving-cell microscopy, the dichroic mirror is fixed and contains a multiband filter. In sequential mode, for each focal position, excitation wavelengths are changed with a fast wavelength switcher, and only one CCD camera is needed. In simultaneous mode, several CCD cameras are used in combination with an adapted detection dichroic mirror...

There is no question that TOF ICP-MS, with its rapid, simultaneous mode of measurement, excels at multielement applications that generate fast transient signals. 

This brand new technique offers up to three simultaneous modes of analysis, depending on the analytes of interest. They do not all need to be used together, but when combined, they offer a very powerful tool for the ultratrace analysis of seawater samples. The three fully automated modes are ... 

The seaFAST 3 offers three simultaneous modes of analysis, which are dictated by the analytes of interest. The three modes are described below ... 

To evaluate the capability of the seaFAST 3, it was coupled with an ICP-MS system (NexION 300, PerkinEhner, Inc., Shelton, CT) to determine 18 elements in seawater samples, using the three simultaneous modes of analysis described." A schematic of the seaFAST sampling system is shown in Figure 20.2. 

The simultaneous mode detectoP divides the electron multiplier into two separate amplifying sections, shown schematically in Figure 3.16. 

Figure 3.16 Schematic diagram showing the functional layout of a simultaneous mode discrete-dynode detector.

Figure 3.17 The current measured (i) at the pulse-counting output of a simultaneous mode multiplier...

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