Energy inputs measures

When long residence time is not needed for chemical reaction or other purposes, small highly powered tank mixers may be suitable, with energy inputs measured in HP/gal rather than HP/1000 gal. They bring together several streams continuously for a short contact time (at most a second or two) and may be used whenever the effluent remains naturally blended for a sufficiently long time, that is, when a true solution is formed or a stable emulsion-like mixture. When it is essential that the mixing be immediate each stream will... 

Specific energy consumption may be expressed as the ratio of the required power input to the effective material throughput and is expressed in kWh.kg [41]. Since mixture uniformity is sensitive to specific energy input, measurement of this parameter can provide an indirect indication of overall product quality for a particular compounding process. 

One can also do work by stirring, e.g. by driving a paddle wheel as in the Joule experiment above. If tire paddle is taken as part of the system, the energy input (as work) is detemiined by appropriate measurements on the electric motor, falling weights or whatever drives the paddle. 

The measure of the system performance is coefficient of performance (COP). For refrigeration applications COP is the ratio of heat removed from the low-temperature level (( Uv) lo the energy input (W) ... 

Consistent bookkeeping is also an important feature of the macro supply curve of conserved energy. Each measure requires, in addition to the data used to calculate the CCE data on the stocks of equipment, turnover rates, etc. The consistent inputs encourage... 

Eor specific applications, we can calculate the ratio of the measure of the goods or sendees provided to the energy input required. For example, in the transportation sector, energy efficiency is based on miles per gallon for personal vehicles, seat-miles per gallon for mass transit, and ton-miles per gallon for freight transportation. 

The temperature dependence of a rate is often described by the temperature dependence of the rate constant, k. This dependence is often represented by the Arrhenius equation, /c = Aexp(- a/i T). For some reactions, the temperature relationship is instead written fc = AT" exp(- a/RT). The A term is the frequency factor for the reaction, which reflects the number of effective collisions producing a reaction. a is known as the activation energy for the reaction, and is a measure of the amount of energy input required to start a reaction (see also Benson, 1960 Moore and Pearson, 1981). 

Mooney Viscometer studies at 100°C and 120°C show lower viscosity of the Al-hlled gums. Lower viscosity compounds require less energy input for extrusion. Comparative results on the dynamic mechanical properties, measured using a rubber process analyzer (RPA), show that at the... 

Here, Q is the heat energy input per area p and Cp are the density and specific heat capacity, respectively and indices g, d, and s refer to the gas, metal, and liquid sample layers, respectively. With Eq. (106), the thermal conductivity of the sample liquid is obtained from the measured temperature response of the metal without knowing the thermal conductivity of the metal disk and the thickness of the sample liquid. There is no constant characteristic of the apparatus used. Thus, absolute measurement of thermal conductivity is possible, and the thermal conductivities of molten sodium and potassium nitrates have been measured. ... 

Two other attempts, without the use of a distribution function, are worth mentioning, as these are operationally related to experiments and serve to give a rough estimate of the thermalization time. Christophorou et al. (1975) note that in the presence of a relatively weak external field E, the rate of energy input to an electron by that field is (0 = eEvd, where vd is the drift velocity in the stationary state. Under equilibrium, it must be equal to the difference between the energy loss and gain rates by an electron s interaction with the medium. The mean electron energy is now approximated as (E) = (3eD )/(2p), where fl = vd /E is the drift mobility and D is the perpendicular diffusion coefficient (this approximation is actually valid for a Maxwellian distribution). Thus, from measurements of fl and D the thermalization time is estimated to be... 

A challenge of a different kind was encountered in the internal vinylation of various vinyl triflates and bromides as depicted in Eq. (11.13) [27]. The electron-rich structures obtained from the reactions were of interest for further use in Diels-Alder reactions, but the risk of degrading the products in the hot reaction medium posed a problem and a prudent choice of energy input was imperative. It turned out that single-mode microwave heating for 5 min at the very low power of 5 W was sufficient to yield 64% of the product with excellent regioselectivity. Measurements with a fluor-optic probe revealed an unexpectedly high temperature of 76 °C [27]. 

The number of rotor revolutions per mix cycle relates directly to unit work input and to temperature rise. This variable can be employed when checking between mixed batches for changes in feeding operations, materials and mixer conditions. Power/work input measures the energy consumed by the mixer. A greater compensation for variations in feed stocks and mixer temperatures is provided by power control. 

Differential thermal analysis (DTA) is a technique in which the temperature difference between a substance and reference material is measured as a function of temperature or time while the substance and reference material are subjected to a controlled increase in temperature. Differential scanning calorimetry (DSC) is a technique in which the difference in energy inputs into the sample and reference material required to keep their temperatures equal is measured as a function of temperature while the substance and reference material are subjected to a controlled increase in temperature [70]. 

The RC1 Reaction Calorimeter is marketed by Mettler-Toledo. The heat-flow calorimetric principle used by the RC1 relies on continuous measurement of the temperature difference between the reactor contents and the heat transfer fluid in the reactor jacket. The heat transfer coefficient is obtained through calibration, using known energy input to the reactor contents. The heat trans-... 

A technique in which the difference in energy inputs into a substance and a reference material is measured as a function of temperature, while the substance and the reference material are subjected to a controlled temperature program. 

Shaffer (S5) also made some exploratory evaluations of the electrostatic atomization of dibutyl phthalate using a camel s hair brush for the atomizing nozzle. On a count basis 73% of the particles were smaller than 10 microns and the largest particle obtained was 40 microns. The energy input corresponded to 0.5 cal/g liquid atomized (0.00026 kWh/lb) and the charge level on the particles as atomized corresponded to a value of Sps of the order of 3-5 V/micron. Current and flow rate measurements reported by Vonnegut and Neubauer (V4) would correspond to an energy input of 0.1 kWh/lb. 

The second parameter of concern applicable for measuring and evaluating energy use is energy efficiency. This provides information about the ratio of energy input and output. 

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