Corona based air-flow using parallel discharge electrodes

A novel air-flow generator based on the effect of ion wind has been developed by the simultaneous generation of both positive and negative ions using two electrodes of opposite polarity placed in parallel. Unlike the conventional unipolar-generators, this bipolar configuration creates an ion wind, which moves away from both electrodes and yields a very low net charge on the device. The electro-hydrodynamic behavior of air-flow has been experimentally and numerically studied. The velocity of ion wind reaches values up to 1.25 m/s using low discharge current 5 mu-A with the kinetic conversion efficiency of 0.65% and the released net charge of �30 fA, 8 orders of magnitude smaller compared with the discharge current. Due to easy scalability and low net charge, the present configuration is beneficial to applications with space constraints and/or where neutralized discharge process is required, such as inertial fluidic units, circulatory flow heat transfer, electrospun polymer nanofiber to overcome the intrinsically instability of the process, or the formation of low charged aerosol

Tri-axis convective accelerometer with closed-loop heat source

In this paper, we report the details and findings of a study on tri-axis convective accelerometer, which is designed with the closed-loop type heat source and thermal sensing hotwire elements. The closed-loopheat source enhances the convective flow to the central part where a hotwire is placed to measure the vertical component of acceleration. The simulation was conducted using numerical analysis, and the devicewas prototyped by additive manufacturing. The device, functioning as a tilt sensor and an accelerometer,was tested up to acceleration of 20 g. The experiments were successfully conducted and the experimental results agreed reasonably with those obtained by numerical analysis. The results demonstrated that the closed-loop heat source could reduce the cross effect between the acceleration components. The scalefactor and cross-sensitivity had the values of 0.26 micro�V/g and 1.2%, respectively. The cross-sensitivity andthe effects of heating power were also investigated in this study

A closed device to generate vortex flow using PZT

This paper reports for the first time a millimeter scale fully packaged device which generates a vortex flow of high velocity. The flow which is simply actuated by a PZT diaphragm circulates with a higher velocity after each actuating circle to form a vortex in a desired chamber. The design of such device is firstly conducted by a numerical analysis using OpenFOAM. Several numerical results are considered as the base of our experiment where a flow vortex is observed by a high speed camera. The present device is potential in various applications related to the inertial sensing, fluidic amplifier and micro/nano particle trapping and mixing

A circulatory ionic wind for inertial sensing application

A novel gyroscope using circulatory electro-hydrodynamics flow in a confined space is presented for the first time. The configuration of the new gyroscope includes three point-ring corona discharge actuators that generate ion flows in three separated sub-channels. The three ion flows then merge together when going through a nozzle of the main chamber entrance and create a jet flow. In the new configuration, the residual charge of ion wind flow is removed by a master-ring electrode located at one end of the main chamber. Under the effect of the angular speed of gyroscope, the jet flow is deflected and this deflection is sensed using hotwires. The results, which are consistently acquired by both the numerical simulation and experiment on our prototypes, demonstrate the repeatability and stability of the new approach. Since the ion wind can be generated by a minimum power, the present configuration-based device does not require any vibrating component. Thus, the device is robust, cost, and energy-effective

Angular rate sensing by circulatory vortex flow: design, simulation and experiment

A fully packaged convective vortex gyrometer actuated by a PZT diaphragm is reported. The flow circulates at higher velocity after each actuating circle to form a vortex in the desired chamber. The vortex is characterized by hotwire anemometry. The device is initially designed based on a numerical analysis whose results are used to set up the experiment. The angular rate sensing of the device is successfully tested using a turntable. The technique is a potential solution to various applications related to inertial sensing and fluidic amplifier

Green Organic Synthesis of N-Methylpyrrolidine

N-methylpyrrolidine was successfully synthesized in an aqueous medium by using methylamine and 1,4-dibromobutane in the presence of catalyst K2CO3 at a moderated temperature. Here, N-methylpyrrolidine was firstly synthesized via the green chemistry process, in which both the water solvent and potassium carbonate catalyst were inexpensive and environmentally friendly. Also, the reaction temperature was quite moderated at 900C. As a result, the current synthesis process was highly potential to implement in practice. Since the product yield directly depended on the operating conditions, the catalysts, temperature, ratio of reactants and solvent would be critical factors. In the present study, the structure of N-methylpyrrolidine product was confirmed by using the IR, 1H-NMR, 13C-NMR and Gas Chromatography-Mass spectroscopy (GC-MS)

An Ontological Approach for Organizing a Knowledge Base to Share and Reuse Business Workflow Templates

International audienceBusiness process models have been used in a lot of enterprise applications. Along with their popularity, the problem of how to create them correctly in terms of semantics and syntax while effectively promoting the reuse of suitable parts of existing models is increasingly interest. This paper describes how to organize a knowledge base to facilitate the shareability and reusability of business workflow templates. We first introduce a repository consisting of business workflow templates which are well-checked at the syntactic and semantic level. An organizational mechanism for control flow-based business workflow templates is therefore provided to ensure an effective search of templates. We then propose a process for developing workflow templates. Thereby for each use case, users can select and modify suitable workflow templates from the knowledge base

Study on point-to-ring corona based gyroscope

We present for the first time a novel gyroscope using circulatory electro-hydrodynamics flow in a confined space. Three point-ring corona actuator is to generate ionic flows in three separated channels and the ionic flows then merge together at a nozzle of the main chamber to create a jet flow. The residual charge of ion winds is removed by a master-ring electrode. By the effect of angular rate, the jet flow handled by a hotwire anemometry is deflected and sensed. Results by both experiment and numerical simulation consistently show good repeatability and stability of the new configuration-based device. Since ion wind is generated by a minimum power, the device does not require any vibrating component, thus the device is robust, low cost and energy consumption

ĐIỀU CHẾ BIODIESEL TỪ MỠ CÁ TRA VỚI XÚC TÁC BAZ RẮN KOH/γ-Al2O3

BIODIESEL PRODUCTION FROM FAT OF TRA CATFISH BY KOH/γ-Al2O3 AS A SOLID-BASE CATALYST The objective of the project is to research the production of biodiesel from fat of Tra Catfish and methanol using K+/γ-Al2O3 as a solid-base catalyst. The results show that KOH/γ-Al2O3 prepared by loading KOH of 7 mmol on Al(OH)3 of 1 g, after being calcined at 550oC for 2 h, which can give the best catalytic activity for this reaction. The maximum conversion of 92,63% has been achieved after 90 minutes, at 60oC when the molar ratio of MeOH to tra fat is 8/1 and 6% KOH/γ-Al2O3 catalyst. The produced biodiesel met the required ASTM D6751 standard.