Papers by Keyword: Response Time

Abstract: In this research, SnO₂ nanostructure thin films were fabricated by spray pyrolysis method, using concentration of tin (Sn) salt solution deposited on a glass substrate at temperature of 450 °C. The tin solution was prepared by solves 2.2563gm of SnCl₂.2H₂O (molecular weight 219.4954 g/mole) in 100 ml of ethanol, then add 60 drops of pure hydrochloric acid ( HCl) using drop by drop technique. Different concentrations of antimony oxide (1%, 2%, 3%, 4%) hve been used to depose the thin films. The structure has been examined by X-ray diffraction technique, which shown that all films are polycrystalline with tetragonal rutile crystalline structure with preferential orientation in the (200) direction and, grain size decreases with increasing doping concentration. Optical measurements shown that the films are transparently in the visible region, with an average transmittance more then 80% and, sharp absorption edge nearly at 350 nm, the nature of the optical transition were direct allowed with band gap varies between (2.97 - 3.75 eV) which is directly proportional to doping concentration. The results also show that the doping has led to improved the response time of the sensing. Two kinds of gases NO₂ and NH₃ have been used to test the sensing performance, at different operating temperatures (R.T, 100, 200, 250, 300 and 350) oC , and bias voltage (3 Volt). For NO₂ gas the highest sensitivity was 77%, the shortest response time 2.9 s and the recovery time 19 s, while for NH₃ gas sensitivity was 11.5%, the response time 4.1 s and the shortest recovery time 20s,

Abstract: Functionalized-multi wall carbon nanotubes (F-MWCNTs) and functionalized-single wall carbon nanotubes (F-SWCNTs) were well enhanced using NiO Nanoparticles. The sensor device consisted of a film of sensitive material (F-MWCNTs/ Nickel oxide nanoparticles) and (F-SWCNTs/ Nickel oxide nanoparticles) deposited by drop casting on n-type porous silicon substrate. The two sensors perform high sensitivity to NO₂ gas at particular temperatures. The analysis indicated that the (F-MWCNTs/NiONPs) have a better performance than (F-SWCNTs/NiONPs). The F-SWCNTs/NiONPs gas sensor shows high sensitivity (18.2 %) at RT with response time 16 sec, while F-MWCNTs/NiONPs gas sensor show better sensitivity (45 %) at RT with response time 26 sec. The device shows a very reproducible sensor performance, with high repeatability, complete recovery and adequate response. A demonstration of the improvement in sensing of NO₂ gas using NiO-functionalized nanotubes is provided.

Abstract: In this work we have studied the electro-optical effect of two types of ferronematic nanoparticles. The first sample doped with magnetic material Fe₃O₄ and the second sample doped with a ferroelectric material SbSI. The difference in the two types of material that has been vaccinated led to different values of electro-optic properties because of the different susceptibility of materials. We have noticed that the material SbSI was more responsive to the applied electric field due to the nature of the constituent material (electric material) than the Fe₃O₄ ferromagnetic. The response time for the material SbSI is less than the response time of the ferromagnetic Fe₃O₄, that led to make the material SbSI best in the optical switch applications.

Abstract: We report on the results of the study of the lateral photovoltaic effect in the Fe/SiO₂/Si structures with n-and p-type silicon. It is found that in both cases the photovoltage signal varies linearly when the light spot moves between the electrodes. It is established that the sensitivity of lateral photovoltaic effect in Fe/SiO₂/n-Si and Fe/SiO₂/р-Si structures is 32.3 and 14.7 mV/mm, respectively. When the silicon conductivity type changes, there is an inversion of photovoltage polarity as a result of the opposite direction of the built-in electrical field at the SiO₂/Si interface. It was found that the response time in the Fe/SiO₂/n-Si structure is 4.2 times faster than in the Fe/SiO₂/p-Si structure due to the presence of an inversion layer in this structure.

Abstract: High voltage DC power supply is very important in laser and high precision instruments, so the stability of high voltage DC power supply has an affect on the stability of laser and equipment. The voltage doubling rectifier circuit is the core component of the high voltage generator, so it is very important to study the stability of the voltage doubling rectifier circuit. Through the study of bidirectional rectifier circuit, double voltage rectifier circuit produces an output ripple and response time is superior than the basic voltage rectifier circuit. At the same time to study the bidirectional rectifier circuit is optimized, the capacity of the output arm greatly increases which leads to reduction in the output ripple, as the capacity reaches large enough value the output ripple approaches zero. Thus, greatly increasing the circuit in steady state time.

Abstract: This study was aimed to test the ability of zinc oxide (ZnO) film fabricated by successive ionic layer adsorption and reaction (SILAR) to detect liquid petroleum gas consisting of a mixture of butane/propane gas. The film was fabricated by alternate dipping of pre-cleaned glass substrates in a sodium zincate bath and in a 95°C hot water bath using an automated dipping machine to control the sequence and dipping time. Scanning electron microscopy (SEM) revealed a uniform film consisting of wurtzite ZnO nanorods for the sample grown using 0.1M concentration of sodium zincate and 200 dippings. Current-voltage characterization of the samples showed an average resistivity of 1.343 Ω-m. EDS analysis of the film confirmed the existence of zinc oxide with 65.9% zinc and 34.1% oxygen. The ZnO film exhibited an ability to detect the gas with an average gas response of 0.44, average response time of 14 seconds and average recovery time of 25 seconds using a gas concentration in air of 1.5 % by volume. Response time is the time for the sensor to reach the peak voltage output from the start of gas exposure while recovery time is the time for the voltage output to return to the initial value without gas when the gas is removed from the chamber. The zinc oxide film also showed a voltage output of 100, 109.31, 118.92, 123.61, 133.5, and 149.52 mV when exposed to percent volume gas concentrations of 0, 0.5, 0.75, 1.0, 1.25, and 1.5, respectively with a correlation coefficient of 0.97. The sensor sensitivity is 32 Δ(mV)/Δ(%conc).

Abstract: In the present work, an experimental investigation has been made to analyze the performance of microchannel heat sink under transient operating conditions. The transient analysis has been made by estimating the response time for different input heat flux and coolant mass flow rate. Analysis has been made for rectangular cross-section microchannels fabricated on a copper block of size 25.7 × 12 × 10 mm³. Twelve (12) numbers of microchannels are fabricated in the copper block. The width and depth of individual channels are 400 μm and 750 μm respectively. Performance analysis has been made for both single phase and flow boiling conditions of the coolant flow using deionized water as coolant. Experiments have been performed for coolant mass flux (G) range of 90 - 250 kg/m²s and input heat flux (q) range of 20 - 300 kW/m² respectively. It has been observed that at constant input heat flux, response time decreases with the increase in coolant mass flux during single phase cooling. However this trend is not strongly followed during the two-phase or flow boiling cooling condition.

Abstract: The Multifunction Vehicle Bus (MVB) protocol is well applied to train network control system where a set of process variables must be transferred between network devices. To cope with the real-time requirements of such system, the MVB protocol is designed to support both periodic and sporadic traffic. The periodic traffic is handled according to a static scheduling table, thus the schedulability can be certain after system initialization. However, for the sporadic traffic, the situation is different due to their irregular occurrence in the system. Therefore, more complex analysis must be made in order to guarantee its timing requirements. In this paper, a schedulability analysis is made by executing worst case response time analysis for sporadic traffic in MVB network.

Abstract: Using basic physical arguments, we present a design and method for the fabrication of a pneumatic micro PDMS actuator using multilayer soft lithography based on dry-film photoresist. Its novel structure consists of a three-way electromagnetic microvalve for gas flow control which is connected with gas inlet microchannel for the actuator. Then the whole system is considered as a throttle blind capacitor (TBC) model and it is used to predict the response time of the pneumatic actuator by correlating its characteristics such as gas pressurizing, air resistance and membrane deformation. For this micro actuator, upward deformation motions of actuated area are observed of actuated area under 100KPa (N₂) pressure and the fast open response (~ 15 ms) was achieved at 50KPa pressure. Our method provides a simple, cheap and save-time pneumatic micro actuator which can be used in active functions, such as valves, pumps and mixers integrated on pneumatic microfluidic chips for downsizing the driving pressure and improving the whole efficiency of microchips.

Abstract: Considering of the thermal resistant of metal Ni-Cr, as well as the insulating characteristic of SiO₂ membrane, aluminium electric line, energetic material, solder and other materials, we designed three MEMS thermo-electric switches, which can realize On-Off (or Off-On) transition to control the initiation of weapon system. We also simulated and analyzed the static and the transient thermal processes and the stress analysis of switches using finite element simulation analysis (FEA) tool ANSYS. The results of temperature distributing, transient response and stress distributing have been obtained.