Platinum sensors

Platinum sensors exploit the fact the electrical resistance of platimum metal is temperature dependent. This behaviour can be described by a polynomial of the form... 

Even conventional hotplates can be fitted with a continuously variable temperature control thanks to platinum thin-film sensors. The encapsulated platinum sensor is positioned so that it is in contact with the cast iron plate from below and thus able to register the temperature of the hotplate. Normally the power supplied to the plate is regulated by a stage switch. The increased control sensitivity is made possible by incorporating electronic circuitry capable of interpreting and acting upon the sensor signals. 

A major growth area for platinum sensor technology is to be found, above all, in ovens. The sensors are used to fulfil two main functions ... 

Our work deals with only a few examples (i) the immunosensor for the forest-spring encephalitis diagnosis (a metal label is used for signal generation), (ii) the enzyme-free urea sensor and (iii) the platinum sensor for antioxidant activity determination. What they all have in common is a screen-printed transducer consisting of graphite or Pt nanoparticles. Transducer configuration is shown in Fig. 27.1. 

Food and herbs are main natural sources of antioxidants. In this connection, antioxidant activity (AOA) of these products is essential for planning right diet as well as for sound therapy. Screen-printed platinum sensor and potentiometric method of measuring AOA of food and herbal extracts are presented below. 

Tester AOT-1 and screen-printed platinum sensor (IVA, Russia) and AgCl/Ag in saturated KC1 solution electrodes were used. 

To sum up, potentiometric determination of AOA with the use of screen-printed platinum sensor provides the possibility to analyze... 

Similar to the DTA system noted above, differential scanning calorimetry (DSC) consists of a sample cell and reference cell, where platinum sensors detect the temperature in each cell. In the case of DSC, however, each cell possesses an individual heater (Figure 18.11B) so that energy input to the individual heaters is recorded as the instrument attempts to maintain equivalent temperatures in each cell while scanning a preset temperature range. The detector thus is able to directly measure the difference in heat capacity between the sample cell and the reference cell. 

Platinum sensors are currently useful because of their potential accuracy and long-term stability in this temperature range. These sensing elements use the... 

An example of the resistive platinum sensor is the hot-wire sensor used for the detection of combustibles [33]. At temperatures of 1(X)0 °C, the resistance and temperature of the platinum increase predictably in the presence of methane and other like gases. This type of sensor has been used in coal mines. Based upon the same phenomenon, a microsensor version boasting lower power consumption and use of less precious metal has been fabricated using photolithography and vacuum evaporation [34]. 

The carbon residue was readily removed by an oxygen treatment at moderate temperature. Almost no silicon or oxygen remained on the surface above 300K. This result cannot explain the poisoning effect of HMDS on platinum sensors used to detect methane in coal mine and other applications. It shows that the mechanism of decomposition of HMDS in the absence of oxygen and at the low... 

Platinum sensor immobilized wifii acetyl-chohnesterase, platinum sensor immobihzed with GOD (glucose oxidase) Antibody-coated SPR-based instrument... 

An array of platinum sensors can be integrated into outer garments to monitor the environmental temperature, which can help in controlling the body thermal-regulations. 

A sample of the air/gas mixture is fed into the analyzer cell at a fixed rate. The cell and sensor are maintained at approximately 1500°F (812°C). the sample ignites, burners and the hot products of combustions (POC s) flow past the ceramic/platinum sensor and produce an electrical voltage proportional to the amount of excess O2 or excess hydrocarbon. The signal is amplified, conditioned and lineraized. A discrete step function occurs when excess hydrocarbon (unburnt fuel) is present in the POC s. This signal is in used an input to the PLC which has a PID control loop output to operate a gas flow control valve to maintain the specified Plasma Valve. 

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