Temperature - default

In the last simulation we found the diode voltage and current at the default temperature of 25°C. Suppose we want to simulate the circuit at a different temperature This can easily be done by selecting the temperature option in the simulation profile. We will continue with the circuit of the previous simulation-... 

We have specified the simulation to run at 100°C. The simulation of the previous simulation did not specify a temperature and the simulation ran at the default temperature of 25°C. Notice in the screen capture above that there is a checkmark El in the box next to the Temperature (Sweep) option. The temperature sweep will not run if this box is not checked. The option above specifies that the Bias Point simulation will run at 100°C. Click the OK button to return to OrCAD Capture. 

Listed in Table 1 are the default values used in the CFD models. For initial calculations, the diameter of granules remained between 1.19mm and 2.38mm, the average of which was assumed as the default. The default flue gas composition is representative of that in a typical oxy-fuel fired furnace. It usually contains a high content of CO2 and H2O. Due to limitations on the expected materials of constmction for a pre-heating system, the default temperature of the incoming flue gas was assumed to be 800°C. 

At this point, the user can inspect the entire input screen and change selected parameters. It is also possible to change the default temperature (298.15°K) or the default diffusion coefficient for each species (1.00 x 10 cmVs). The diffusion coefficients are changed by entering a multiplier of the default value (e.g., enter 0.5 for a diffusion coefficient of 5.00 x lO cm s). If it is desired to simulate a mechanism with a diffusion coefficient larger than the default coefficient, the default diffusion coefficient itself can be changed. 

The default temperature in FITEQL is 298.15 K. If temperatures different from this default value are to treated, this is not possible with models that include the diffuse layer, because the Gouy-Chapman formalism, Eq. (12), includes temperature either directly or indirectly via the temperature dependence of . ... 

DX(1) cols 1-10 increment for derivative with respect to the temperature, default value is 0,5... 

T temperature (K) of isothermal flash for adiabatic flash, estimate of flash temperature if known, otherwise set to 0 to activate default initial estimate. 

This thinking has carried through to the present day and is reflected in our choices of mobile-phase fluids in LC water, acetonitrile, methanol, tetrahydrofuran, hexane, etc., are still among our popular choices. However, these particular materials are completely dependent on the conditions of column temperature and outlet pressure. Tswett s original conditions at his column outlet, actually the earth-bound defaults we call ambient temperature and pressure, determined his solvent choices and continue to dominate our thinking today. 

Keyboard sixteen push-buttons for entry of data and instructions for manual or automatic calibration, based on the three National Bureau of Standards (NBS) buffers of pH 4, 7 and 9, whose values as a function of temperature have been permanently and separately stored to three decimal places and at intervals of 0.1° C. Hence there is no need to enter pH values, as the electrode automatically identifies the buffer in use and the apparatus immediately retrieves and displays the temperature-adjusted buffer value the isopotential adjustment is defaulted to pH 7.000. 

Set a constraint for each basis member that you want to include in the calculation. For instance, the constraint might be the total concentration of sodium in the fluid, the free mass of a mineral, or the fugacity of a gas. You may also set temperature (25 °C, by default) or special program options. 

For the g2SC phase, the typical results for the default choice of parameters H = 400 MeV and r/ = 0.75 are shown in Figure 4. Both the values of the diquark gap (solid line) and the mismatch parameter 5/j, = /i,./2 (dashed line) are plotted. One very unusual property of the shown temperature dependence of the gap is a nonmonotonic behavior. Only at sufficiently high temperatures, the gap is a decreasing function. In the low temperature region, T < 10 MeV, however, it increases with temperature. For comparison, in the same figure, the diquark gap in the model with /je = 0 and /./, = 0 is also shown (dash-dotted line). This latter has the standard BCS shape. 

The value of the PSpICe Template property generates the PSpice netlist line for the resistor when you create a netlist for the schematic. The TC property is a temperature coefficient for the resistor. Its default is zero (no temperature dependence). The property Value is the value of the resistor in ohms. The Source Library (not shown in the screen captures above) is the name of the. olb file in which the part is located. 

We will now use PSpice to find the diode current and voltage in the circuit of Figure 3-2. The diode current is given as Id= Is[exp(VD/riVT) - 1], Is is the diode saturation current and is 10 15 amps for this example. VT is the thermal voltage and is equal to 25.8 mV at room temperature, ri is the emission coefficient for the diode and its default value is 1. PSpice automatically runs all simulations at room temperature by default. 

The Bias Point simulation is already selected from the previous example. Here we need to specify the temperature of the simulation. By default, all simulations are run at 25°C. To specify a temperature other than the default, select the... 

Most of the devices used by PSpice can include temperature effects in the model. Most of the semiconductor models provided by Oread include temperature dependence. By default, the passive devices such as resistors, capacitors, and inductors do not include temperature dependence. To make these items include temperature effects, you will need to create models that include temperature effects. The temperature dependence of resistors is discussed in Section 4.G.I. In this section, we will show only how the I-V characteristic of a 1N5401 diode is affected by temperature. The D1N5401 diode model already includes temperature effects so we will not need to modify the model. We will use the standard resistor, which does not include temperature effects. We will continue with the circuit of Section 4.B ... 

TCI is referred to as the linear temperature coefficient and TC2 is referred to as the quadratic temperature coefficient. Tnom is the nominal temperature. Its default value is 27°C. 

The default values of TCE, TCI, and TC2 are zero. Thus, if you do not specify any of the coefficients, there will be no temperature dependence. In all of our previous simulations the resistors had no temperature dependence. Thus, if we varied temperature in any of the simulations, the resistors would not be affected. To add temperature dependence we must specify the temperature coefficients. 

This circuit is a bridge rectifier followed by a filter capacitor to produce a DC voltage with ripple at Vin. Connected to Vin is a linear regulator made from a Zener voltage reference and an NPN pass transistor. We will first run a Transient Analysis to see the operation of the circuit at room temperature (27°C). To set up a Transient Analysis, select PSpice and then New Simulation Profile from the Capture menus, enter a name for the profile and then click the Create button. By default the Time Domain (Transient) Analysis type is selected. Fill in the parameters as shown in the Time Domain dialog box below ... 

Tnom - the nominal temperature, 27°C Note that if an inductor model is not specified, all model parameters are set at their default values and the value in the simulation is the value specified in the schematic. 

Of course all surfaces that are at such low temperatures must be kept out of contact with the ambient environment. This is achieved by a detachable and rotable vacuum shroud that surrounds the two expander stages and the sample, all of which must be kept under high vacuum while they are cold to avoid collisional heat transfer. By default, evacuation of the assembly occurs through vacuum ports mounted on the main body of the expander, but in some cases it is advantageous to have extra ports on the vacuum shroud itself. Furthermore, the first expansion stage of closed-cycle cryostats, where a temperature of 35 10 K is attained, is usually fitted with... 

Aside from the question of the precise model by which relaxation times are interpreted there is the more practical problem of isolating that part of the relaxation specifically caused by diffusion. The contributions of exchange processes (see below), spin-rotation interaction (9), and spin diffusion (9) can be identified by temperature dependences different from that which is solely the result of the motionally modulated nuclear dipolar interaction as sketched above, and corrections can be made. The molecular rotation contributions to dipolar relaxation can be removed or corrected for by (a) isotopic substitution methods (19), (b) the fact that rotation is in some cases much faster than diffusion, and its relaxation effects are shifted to much lower temperatures (7, 20), and (c) doping with paramagnetic impurities as outlined above. The last method has been used in almost all cases reported thus far, more by default than by design, because commercial zeolites are thus doped by their method of preparation this... 

Few oxidation methods have enjoyed the almost immediate success of the Swern procedure for the oxidation of alcohols. Since the publication of three foundational papers161 in 1978-79, Swern has become the de facto oxidation method by default whenever activated DMSO is desired. It offers the advantage of quite consistent good yields in many substrates, with an operation performed under very low temperature and mild conditions. Swern s procedure consists of the oxidation of an alcohol using DMSO, activated by reaction with oxalyl chloride. According to Swern, oxalyl chloride is the most effective activator of DMSO examined by his group.162 It must be mentioned that Swern s research team is probably the one that has tried the highest number of DMSO activators for the oxidation of alcohols. 

The temperature of the seabed is known to be 42°F, but the downstream end of the pipeline will be colder than this (38°F) due to Joule-Thompson cooling when it is vented. A porosity of 0.5 and a permeability of 0.01 mD are default values. An annulus spacing of 0.1 is required for pressure flow communication. 

Figure B.2 shows the layout of CSMPlug for a 2SD calculation. Inputs to the model are ambient and dissociation temperature, hydrate structure, plug porosity, and the pipeline diameter. Selecting the default values option on the 2SD tab or from the defaults pull down menu will enter the default values. The default values for the parameters can be seen in Figure B.2.

An sll hydrate blockage occurs in an 18-in. diameter insulated pipeline. The seabed temperature is known to be 41°F. The heat transfer coefficient is known to be 4 Btu/h ft2oF. The default values for the hydrate dissociation temperature and plug porosity will be used. 

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