why is the smart grid needed

... through the circuit, meaning that the current flowing through two different resistors should be the same The input voltage, Vin, is the voltage rise V1 is the voltage drop across R1, and V2 is across ... color band is very close to the lead while the right band is further away from the other lead If not, you have to flip it around In some cases, there may exist some distance between the third and ... system, for exclusive use by the purchaser of the work Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its...

Ngày tải lên: 18/02/2014, 22:20

... anticipated, it is easy to isolate or decouple the load with a resistor; see Figure 4.5 Note that the series resistor will attenuate the output signal unless the load resistance is very high If this is a ... if this second logic output is not needed, the VREF and VT2 pins can be connected together and the two resistors replaced by a single resistor whose value is equal to the sum of their resistances ... temperature, the power device’s power dissipation, and the thermal resistance from the case to the heat sink Similarly, the power device’s case temperature depends on the device’s power dissipation and the...

Ngày tải lên: 13/12/2013, 05:15

... the thermal expansion of the substrate is dominated over the thermal contraction of the fiber, and the wavelength shift is governed by the strain induced by the substrate thermal expansion and thermo-optic ... coefficient of the base may add the extra nonlinearity in the shift The theoretical prediction of the nonlinearity in the thermal response of the Bragg wavelength was described in [11,12] The sensor’s ... coefficient of the fiber, Transmitted α is the coefficient of thermal expansion Pitch Λ λ and ξ is the thermo-optic coefficient A change in the effective refractive index and/or the grating period...

Ngày tải lên: 05/03/2014, 14:20

... have been established during this period This Chapter reviews the existing designs and discusses the advantages and disadvantages of each As the research focus in this thesis is on temperature ... fdrive is the driving frequency of the heater, r is the distance to the heater which in this work is 24µm and is accurately determined especially in latest technologies Therefore if the fdrive is ... given The discussion and comparison with other state-of -the- art works are also presented Chapter summarizes the findings of this thesis The future works are also suggested at the end of the Chapter...

Ngày tải lên: 09/09/2015, 11:33

... by adding the solar panel’s thermal time constant to the hysteresis To select the set point resistors, consult the thermistor data sheet for the thermistor’s value at the desired temperature For ... Hysteresis is set by the difference between the high and low set points The slope of the TC620’s internal PTC resistor is about 430 Ω/°F, so 5°F of hysteresis occurs when the low set point resistor is ... switch is closed, the third driver is disabled and the fourth driver is enabled to control the cooling contactor This driver turns on the cooling contactor when the TC620’s control output is high The...

Ngày tải lên: 11/01/2016, 11:38

... inverts the Regulate output logic This is necessary when using “NTC”-type thermistors because the internal logic is designed to function with a “PTC”-type thermistor The external thermistor used ... hysteresis is set for a wide (20°F) span The thermal time constant of the solar panel will also aid in the prevention of rapid pump cycling, if the thermal resistance between the thermistor assembly ... switch is closed, the third driver is disabled and the fourth driver will be enabled to control the cooling contactor This driver will turn on the cooling contactor when the Regulate output is high...

Ngày tải lên: 11/01/2016, 11:38

... data The filtering is accomplished by counting the number of pulses in a fixed time window A block diagram of the architecture of the ∆Σ ADC is given in Figure 10 The first part of the ADC is a ... temperature measurement data is stored in the Temperature Register, while the TC72 Control Register or TC77 Configuration Register is used to select the operating mode of the sensor The Manufacturer’s ... the package The Ground pin of the IC provides a low-impedance thermal path between the die and the PCB, allowing the sensor to effectively monitor the temperature of the PCB board The other non-grounded...

Ngày tải lên: 11/01/2016, 14:31

... oscillators The RSS analysis consists of listing the magnitude of all the error terms and then multiplying the terms by the component sensitivity factor Next, the sum of the square of each error is calculated ... Comments The sensitivity of the resistors is defined as the relative change in the oscillation frequency per the relative change in resistance ((∆fo/fo)/(∆R/R)) The sensitivity of the capacitors is ... Note The sensitivity of the resistors is defined as the relative change in the oscillation frequency per the relative change in resistance ((∆fo/fo)/(∆R/R)) The sensitivity of the capacitors is...

Ngày tải lên: 11/01/2016, 14:35

... Forward Current IS = Saturation Current IS is a constant variable defined by the transistor size A constant forward current (IF) is used to bias the diode, which makes the temperature TA the only changing ... when TA is equal to Thot or Tcold , the 2nd order term is forced to zero, with no error added to the 1st order error term This is because the error at the Thot and Tcold temperature extremes is included ... Most likely, the person doing so is engaged in theft of intellectual property • Microchip is willing to work with the customer who is concerned about the integrity of their code • Neither Microchip...

Ngày tải lên: 11/01/2016, 16:35

... concentration is too high, then the platinum particles coagulate each other This coagulation might have reduced the effective catalyst surface area and spill-over probability The transient responses of the ... with the repeated exposure to hydrogen The improvement in response could be interpreted by the accumulation of the water in the film generated by hydrogen exposure The response to the humid gas is ... deficiencies, we limit the discussion to the gas reduction/oxidation of WO3 The basic concept is the formation of tungsten bronze with the intercalation of hydrogen ions But the oxygen removal by...

Ngày tải lên: 19/03/2014, 16:47

... on the electronegativity of the metal cation The electronegativity is the measure of the Lewis acid site activity The relative measure of the oxide activity in oxidation reactions can be the ... In fact, the less the energy of oxygen atom isolation from the oxide surface is, the higher the oxide oxidizing ability is The reactivity of oxides in acid–base reactions depends on the electronegativity ... of the nitrogen atom The other is that there is a lone electron pair in NH3 What is more important is that lowtemperature ammonia oxidation was observed over iron oxide [26,27] That is, the...

Ngày tải lên: 19/03/2014, 16:47

... Thus, when the thin film is exposed to NH3 gas, the adsorption and desorption processes will simultaneously occur, and the thinner the films, the quicker the gas desorption Then, the resistance attains ... may be due to the surface adsorption effect, and the chemisorptions leads to the formation of ammonium However, the interaction process between the thin film and the adsorbed gas is a dynamical ... are possible [16] It is believed that the porous structure of thin films leads to the predominance of surface phenomena over the bulk material phenomena, and therefore the resistance increases significantly...

Ngày tải lên: 20/03/2014, 13:04

... response is 337, 220, 168, 112 and 80% The dielectric loss response is much higher than the capacitance response These results are in good accordance with the data in Fig Response time is one of the ... responses to the stepwise decreases of the NH3 concentration at a frequency of 10,000 Hz in Fig From the plot we can see that the capacitance of the device increases along with the increasing ... It is clearly evident that the LSCO nanotube sensor exhibits a greater sensitivity towards NH3 The detection limit of the LSCO nanotube sensor is several ppm The capacitance varied with the...

Ngày tải lên: 20/03/2014, 13:04

... further analysis The selection of the sensor’s working temperatures is discussed in detail in the next section Data acquisition started before the injection of the vapour sample into the airflow ... maximise the variance between classes [37] The two predefined classes were ethanol and H2 S, and the data matrices were the same as the ones used for the PCA analysis The scores plot of the DFA ... and then the vapour was injected into the sensor chamber A drop of the sensor resistance took place as the ethanol, i.e., a reducing species, was oxidised by the adsorption of oxygen onto the...

Ngày tải lên: 20/03/2014, 13:04

... in the sample is metallic [26] Surface elemental analysis reveals that the atomic ratio of Ag/Fe is 1/30 This value is higher than the theoretical one, which indicates that the Ag dopant is well ... between the sensor and the test gas [34] The two factors together contribute to the improvement of gas sensing properties of the Ag-doped ␣-Fe2 O3 sensors Furthermore, the maximum response is observed ... Ag is wt% When the Ag content is larger than wt%, the surface areas become to decrease unexpectedly This should be attributed to the aggregation of Ag particles, resulting in the decrease of the...

Ngày tải lên: 20/03/2014, 13:04

... when the gas is turned on and off, respectively The device response vs time is shown in Fig for 0.1 vol% of LPG From the plot, it is seen that the response time is 140 s and the recovery time is ... vol% This may be due to the presence of sufficient gas molecules at the interface of the junction for reaction to occur From the same graph, it is found that for higher concentrations of LPG, the ... heterojunction in the absence and presence of LPG at room temperature (300 K) Curve (a) in Fig shows the I–V characteristic in the absence of LPG and curves (b–e) are in the presence of LPG for the concentrations...

Ngày tải lên: 20/03/2014, 13:07

... experienced by the carriers in the bulk of the grain becomes comparable with the number of surface collisions because of the comparable dimension between the mean free path of the carriers and the very ... explained with the conventional space charge model One of the conceivable mechanisms is the adverse effect of adsorbed analytes on the mobility of free charge carriers The number of collision experienced ... analyte vapor over it with the flow rate of 500 ml/ while monitoring the resistances of the sensing layer and the heater Figure shows the variations of normalized resistances at four different...

Ngày tải lên: 20/03/2014, 13:07

... experienced by the carriers in the bulk of the grain becomes comparable with the number of surface collisions because of the comparable dimension between the mean free path of the carriers and the very ... explained with the conventional space charge model One of the conceivable mechanisms is the adverse effect of adsorbed analytes on the mobility of free charge carriers The number of collision experienced ... analyte vapor over it with the flow rate of 500 ml/ while monitoring the resistances of the sensing layer and the heater Figure shows the variations of normalized resistances at four different...

Ngày tải lên: 20/03/2014, 13:07

... respectively This can be explained by considering the temperature dependence of the surface coverage of chemisorbed species At low temperature, there is physisorption, but the rate of chemisorption is negligible ... considering the effect of surrounding gases on the surface of the grains constituting the sensitive layer on the one hand and the electronic transport mechanisms in and between the grains on the other ... account the two types of W–O bonds of the WO3 crystalline structure The electrical charge of the transition zone that lies at the periphery of the grains is induced by the environment of the layer The...

Ngày tải lên: 20/03/2014, 13:12

... K␣ radiation The working pressure in the analysis chamber was maintained below × 10−7 Pa during the specimen analysis To eliminate the effect of sample surface charging the shift of the XPS peak ... measurement The operating voltage (VH ) was supplied to either of the coils for heating the sensors and the circuit voltage (V C = 10 V) was supplied across the sensors and the load resistor (R ... peaks can be observed in the XRD In general, the sensitivity of the sensor is affected by the operating temperature Fig shows the relationship between the gas sensitivity and the operating temperature...

Ngày tải lên: 20/03/2014, 13:12