Generating efficient chaos effect in micro channel using electrohydrodynamic theory

AC electro-osmotic flow is a promising technique in microfluidic manipulation. AC electroosmotic force has been generated inside a novel twisted micro channel in order to overcome the low Reynolds number fluid. The behavior of concentration distribution has been investigated by solving the transient electric field, fluid mechanic and convection-diffusion theory inside the channel. Two particles have been released inside the channel to investigate the efficiency of generated chaotic regime. Velocity streamlines and perturbation of species concentration reveal high performance stirring process which above 95% mixing efficiency achieved for 210 μm channel length. The efficiency increases by increasing the applied voltage amplitude. Geometrical and exciting parameters have been optimized in order to maximize the efficiency of mixing process and avoid electrolysis and sample damage

A Novel Hybrid Continuous Time / Discrete Time Multi Stage Noise Shaping Structure Dedicated to MEMS Based Accelerometer

Abstrac

Synthesis and characterization of hydrophobised magnetite nanoparticles for production of liquid marbles and modeling of liquid marble deformation under the gravity effect

Liquid marbles are emerging discrete droplet microfluidic systems that are a simple alternative to conventional droplet microfluids encapsulated by hydrophobic nanoparticles or micro-particles. One of the most important applications of liquid marbles is their use in biochemistry, biomedicine, nanotechnology and so on. In this research, liquid marbles are studied in two parts of practical and simulation. In the practical part, for the production of liquid marbles, magnetite nanoparticles are first synthesized and hydrophobised with paraffin wax. In the next step, using a micropipette, a droplet of water is placed on the nanoparticles and by tilting the surface, it is rolled on the nanoparticles, which finally forms a "liquid marble". Finally, the opening and closing of the powdery shell studied using a magnetic field induced by a fixed magnet. In the simulation section, by modelling the marble with an elastic shell around the droplet, the effect of the gravitational force on it, was examined and it was observed that the simulation results show well agreement with the practical part

Generating efficient chaos effect in micro channel using electrohydrodynamic theory

745-753AC electro-osmotic flow is a promising technique in microfluidic manipulation. AC electroosmotic force has been generated inside a novel twisted micro channel in order to overcome the low Reynolds number fluid. The behavior of concentration distribution has been investigated by solving the transient electric field, fluid mechanic and convection-diffusion theory inside the channel. Two particles have been released inside the channel to investigate the efficiency of generated chaotic regime. Velocity streamlines and perturbation of species concentration reveal high performance stirring process which above 95% mixing efficiency achieved for 210 μm channel length. The efficiency increases by increasing the applied voltage amplitude. Geometrical and exciting parameters have been optimized in order to maximize the efficiency of mixing process and avoid electrolysis and sample damage

In-situ AC electroosmotic and thermal perturbation effects for wide range of ionic strength

AC electrokinetic flow is promising in designing microfluidic chips for manipulation of biological and chemical samples toward clinical diagnostics. Four pieces of electrodes are optimized to enhance mixing effect inside a straight microchannel. In this research, the mixing dependency on the ionic strength of solutions is investigated. AC electroosmotic secondary flow is responsible for the mixing at low ionic strength (σ < 5 mS m–1), whereas AC electrothermal secondary flow is proposed to mix high conductive mediums (σ > 5 mS m–1). The electrode-electrolyte impedance analysis is employed to facilitate the in-situation mixing process by choosing appropriate electrical excitation parameters for the electrodes

Using a Photoacoustic Cell for Spectroscopy of Toxic Air Pollutants including CO₂, SO₂ and NO Gases

Due to the rise in global temperature and climate change, the detection of CO2, SO2 and NO pollutants is important in smart cities. In this paper, an H-shaped photoacoustic cell is utilized for the detection of low-concentration gases. The geometry of the cell is miniaturized and designed with specific parameters in order to increase its efficiency and performance. The designed cell eliminates problems such as bulkiness and cost, which prevent the use of sensors in detecting greenhouse gases. The simplicity of the design expands the application rate of the cell in practice. In order to consider the viscosity and thermal effects, the cell is formulized by fully linearized Navier–Stokes equations, and various parameters, such as acoustic pressure, frequency response, sound speed (sound velocity) and quality factor, are investigated for the mentioned gases. The performance of the system is frequency-based, and the target gases can be detected by using a microelectromechanical resonator as a pressure sensor. Quality factor analysis expresses that CO2, SO2 and NO gases have quality factors of 27.84, 33.62 and 33.32, respectively. The performance of the cell in the resonance state can be expressed by the linear correlation between the results. The background noise generated in the photoacoustic research has been removed by miniaturization due to the obtained resonance, and the proposed cell provides a proper signal-to-noise ratio. The results of the proposed system represent the increase in the quality factor, which reduces the losses and thus increases the sensitivity of the system in the study of greenhouse gases

Numerical Simulation of a Novel Electroosmotic Micropump for Bio-MEMS Applications

High lamination in microchannel is one of the main challenges in Lab-On-a-Chip’s components like micro total analyzer systems and any miniaturization of fluid channels intensify the viscose effects. In chip-scale, the electroosmotic flow is more efficient. Therefore, this study presents a MEMS-based low-voltage micropump for low-conductive biological samples and solutions, where twelve narrow miniaturized microchannels designed in one unit to efficiently using the electroosmotic effects which generated near the walls. Four microelectrodes are mounted in lateral sides of the microchannel and excited by low-voltage potential to generate pumping process inside the channel. We sweep the voltage amplitude and a linear variation of fluid velocity achieved by Finite-Element-Method (FEM) simulation. We obtain a net average velocity of 0.1 mm/s; by applying 2 V and -2 V to the electrodes. Therefore, the proposed low-voltage design is able to pumping the low-conductive biofluids for conventional lab-on-a-chip applications

Stilbopinae, a new subfamily for the Iranian fauna

Systematic study of Ichneumonidae was carried out during 2009 to 2012 in Sari region and suburb.In this study Malaise trap, Window trap, Yellow Pan trap, Light trap and Sweeping trap were used for collecting. Stilbops vetula (Gravenhorst, 1829) from Stilbopinae subfamily is reported for the first time from Iran

Application of Ion Mobility Spectrometry for Determination of Morphine in Human Urine

Abstract: In this study, a rapid, simple and sensitive ion mobility spectrometry (IMS) method with corona discharge as ionization source was described for the morphine determination in human urine. Morphine was extracted and purified from urine samples using solid phase extraction procedure with C 18 column. It can offer the clean extracts which no extra peaks were observed in IMS. Under operating experimental conditions (Temperature; injection: 220 and oven: 180 o C, Flow rate; carrier: 300 and drift: 600 mL min -1 , Voltage; corona: 2200 and drift: 6700 V), developed method showed good linearity in the ranges of 0.44 to 6.91 and 6.91 to 22 ng mL -1 with correlation coefficients (R 2 ) of 0.9979 and 0.9966, respectively. The limit of detection was 0.1 ng mL -1 , and precision as relative standard deviation was 11%. The capability of the proposed method was evaluated by the analysis of human urine as a real sample that satisfactory results were obtained

OPIOIDERGIC AND CHOLINERGIC BUT NOT NITRIC OXIDE PATHWAYS ARE INVOLVED IN ANTINOCICEPTIVE ACTIVITY OF VITEX AGNUS-CASTUS ESSENTIAL OIL IN THE ACUTE TRIGEMINAL MODEL OF PAIN IN RAT

 Objective: Vitex agnus-castus (VAC) and its essential oil traditionally used to treat many conditions and symptoms such as premenstrual problems,mastalgia, inflammation, sexual dysfunction and pain. This study was conducted to investigate the analgesic effect of essential oil extracted from VAC(EOVAC) leaves in acute trigeminal model of nociception in adult male Wistar rats. Furthermore, possible involvements of opioidergic, cholinergic andL-arginine/NO/cyclic GMP pathway in analgesic activity of EOVAC were investigated.Methods: The EOVAC was extracted from powdered plant material by hydro-distillation in a Clevenger type apparatus. Acute trigeminal pain wasinduced by putting a drop of NaCl 5 M solution (40 μl) on the corneal surface of the eye and the numbers of eye wipes counted during the first 30 seconds.Results: EOVAC at doses of 100 and 200 mg/kg subcutaneous and morphine 2.5 and 5 mg/kg i.p. produced a significant anti-nociceptive effect inthis model of corneal pain. Naloxone (1 mg/kg i.p.) and atropine (1 mg/kg i.p.), L-arginine (100 and 200 mg/kg i.p.) and methylene blue (5 and10 mg/kg i.p.) alone had no any effect in the acute corneal pain. Pretreatment with naloxone or atropine significantly reversed the EOVAC‑inducedanalgesia, but L-arginine (300 mg/kg) and methylene blue (5 mg/kg) did not change the suppressive effect of EOVAC on pain response.Conclusion: The present results suggest that the EOVAC produced anti-nociception in the acute corneal pain through mechanisms that involved bothopioidergic system and/or the cholinergic system, but not via L-arginine/NO/cyclic GMP pathway, supporting the folkloric usage of the plant to treatvarious painful processes.Keywords: Acute trigeminal pain, Vitex agnus-castus essential oil, Opioidergic system, Cholinergic system, Rat