Combination Of Mixer Research Articles

Parametric optimization of back-contact T-C-O-free dye-sensitized solar cells employing indoline and porphyrin sensitizer based on cobalt redox electrolyte

Transparent-conductive-oxide-free (T-C-O-free) back-contact (B-C) dye-sensitized solar cell (DSC) utilizing flexible Stainless Steel (SS) mesh (SS-mesh) supported with mesoporous TiO2 as a photoanode employing cobalt electrolyte is being presented. A thin layer of Ti metal over the SS-mesh was ascertained to be essential to retard the back electron reaction, which was confirmed by the dark current measurements. The interfacial contact between the SS-mesh and nanoporous (NP) TiO2 of the photoanode of T-C-O-free B-C-DSC was driven to influence the photovoltaic performance greatly. It was confirmed by electrochemical impedance analysis that NP TiO2 of 30 nm exhibited less charge transfer impedance observed at TiO2-dye-electrolyte interface as compared to TiO2 of having particle size of 15–20 nm. T-C-O-free B-C-DSC employing dye mixer combination of indoline dyes D-131 and D-205 (1:1) with relatively larger NP of TiO2 (30 nm) as compared to TiO2 of 15–20 nm exhibited enhanced photoconversion efficiency (PCE) of 4.02%. To increase the PCE even further, T-C-O-free B-C-DSC with cobalt based electrolyte sensitized with porphyrin (YD2-o-C8)-dye bearing a larger optical window was investigated. An optimized 10 µm thickness of the TiO2 layer was found to be optimum leading to an enhanced PCE of 5.26%.

Evaluation of Mixing Uniformity for Inline Mixers by Image Processing

HighlightsFour inline mixers with different structures are designed and tested for DNIS applications.A new method for evaluating inline mixing uniformity by image processing is presented.While higher carrier flow rates cause better uniformity, changes due to higher mixing ratios are complicated.The multi-injection jet mixer has simplified structure and relatively satisfactory mixing efficacy.Abstract. Effective and specialized mixing devices that can achieve pesticide injection and inline mixing simultaneously are required to achieve better mixing efficacy in direct nozzle injection systems (DNISs), especially when high-viscosity pesticides are used. To evaluate the inline mixing efficacies of four inline mixers with different structures under various application conditions and to propose optimized structures for those inline mixers, a new method for evaluating uniformity based on image processing is presented. The results of experiments show that the proposed method is adequate for determining mixing uniformity. The mixing uniformity of each mixer increased with carrier flow rates (Q) ranging from 800 to 2,000 mL min-1, but the variations were less significant than those achieved by varying the mixing ratio (P) from 1:100 to 10:100. The mixing uniformity in the jet mixer (mixer A) clearly decreased with an increase in P at different values of Q because the pesticide gradually concentrated on one side of the detection tube. The layered mixer (mixer B) performed better than mixer A, especially at high P. The extension tube installed downstream of mixer B to improve uniformity was shorter than that of mixer A. Mixer C, whose structure was a combination of mixers A and B, had optimal mixing efficacy and the most complicated structure. The uniformity of the multi-injection jet mixer (mixer D) (Haverage = 12.46) obtained by simplifying mixer C was superior to that of mixers A (Haverage = 15.35) and B (Haverage = 14.65) but inferior to that of mixer C (Haverage = 4.08). With a relatively simple structure, mixer D may generally meet the uniformity requirements, thus resulting in advantages for practical use in DNISs, although further structural optimization of mixer D seems necessary. Keywords: Direct nozzle injection system, Image processing, Inline mixers, Mixing uniformity, Principal component analysis, Various application conditions.

Design and Validation of an Additively Manufactured Flow Cell–Static Mixer Combination for Inline NMR Spectroscopy

There have been an increasing number of publications on flow chemistry applications of compact NMR. Despite this, there has been so far no comprehensive workflow for the technical design of flow cells. Here, we present an approach that is suitable for the design of an NMR flow cell with an integrated static mixing unit. This design moves the mixing of reactants to the active NMR detection region within the NMR instrument, presenting a feature that analyzes chemical reactions faster (5–120 s region) than other common setups. During the design phase, the targeted mixing homogeneity of the components was evaluated for different types of mixing units based on computational fluid dynamics simulation. Subsequently, the flow cell was additively manufactured from ceramic materials and metal tubing. Within the targeted working mass flow range, excellent mixing properties as well as narrow line widths were confirmed in validation experiments, comparable to common glass tubes.

Analysis of the variability of pesticide concentration downstream of inline mixers for direct nozzle injection systems

The injection of pesticide directly into spray nozzles results in concentration variations, both periodic discontinuities and pulses, caused by the use of injection pumps and solenoid valves. Such variations can lead to inaccurate application of pesticide. To avoid using long pipelines, long lag times and inaccurate application, efficient mixers are required to shorten the distance between the injection point and the spray nozzle. To analyse concentration variations and periodic pulses, a set of methods based on image processing were proposed and were tested using three inline mixers, a jet mixer (A), a layered mixer (B) which was specially designed, and simplified layered-jet mixer (C) which was developed as combination of mixer A and some simplified structures of mixer B. Results showed the characteristics of concentration variability for three mixers were generally different. The application conditions, carrier flow rate, mixing ratio, and injection frequency, need to be comprehensively considered to achieve improved concentration consistency and improve spraying accuracy. Concentration variability was the most obvious for mixer A with the average Coefficient of Variation (CV) as high as 4.12%. Using auto-correlation and complexity analysis, the concentration series exhibited strong periodicity and relatively lower complexity. Concentration variability for mixer B was less prominent with an average CV value 1.25% and concentration periodicity sometimes being indeterminable. Mixer C showed moderate concentration variability (CV 2.26%) although pulsation was still detectable. Mixers with similar structures to mixer C could be applied for direct nozzle injection systems to improve the spraying accuracy.

A study of mixing performance of polyacrylamide solutions in a new-type static mixer combination

In this paper, the performance of a Kenics and SMX static mixer combination is investigated with regard to the specialty of tertiary oil recovery. The experiment has the same scale with industrial process as the diameter of test static mixers are 50mm and the effective length are 1500mm. The experiment mainly focuses on degradation of polyacrylamide solutions of different concentrations and different relative molecular mass, the pressure drop of the static mixer combination and mixing performance of polyacrylamide solutions through the static mixer combination. The experimental results show that the degradation rate of polyacrylamide solutions and non-uniformity degree are positively related to polyacrylamide solution concentrations, relative molecular mass of polyacrylamide and liquid phase flow rate. With more solvent distributed among the macromolecular chain entanglements, the flow resistance of macromolecules is reduced, which leads to the reduction of the viscosity of HPAM solution. This phenomenon mainly accounts for the degradation of polyacrylamide solutions. In this study, the pressure drop of the static mixer combination and non-uniformity degree of product solution have obvious advantages compared with other static mixers used in the same way. The results show that the static mixer combination is very suitable for mixing process of polymer solution and water from oilfield.

Cooling Crystallization of Paracetamol in Hollow Fiber Devices

We examine here cooling crystallization of aqueous paracetamol solutions in hollow fiber devices. It is shown that a solid hollow fiber crystallizer (SHFC)−static mixer assembly can be operated successfully up to 30−40°C below the metastable zone limit. Such a capability is not existent in industrial cooling crystallizers; it allows the decoupling of nucleation and growth, an opportunity offered currently only by impinging jet mixers for antisolvent crystallization. In addition, it leads to the achievement of very high nucleation rates and hence small crystal sizes. The former were 2−4 orders of magnitude higher than values previously obtained in solid hollow fiber crystallizers for potassium nitrate and salicylic acid and reached values encountered only in impinging jet crystallization. A qualitative comparison with existing literature data showed that the SHFC−static mixer combination confined the crystal size distribution (CSD) to smaller sizes and a narrower range. Finally, a linear relationship betwe...

MMIC compatible lightwave-microwave mixing technique

The work presented here concerns the mixing of a microwave signal with a modulated optical signal in a MESFET. A brief theoretical analysis of the mixing mechanism is given in terms of the input signal parameters and device characteristics. Experimental results for the IF response of the MESFET as a function of RF frequency, incident optical power, optical modulation depth and gate bias voltage are shown. The IF response and the noise figure of the MESFET below 700 MHz were smaller than those of a p-i-n detector/Schottky mixer combination.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Noise performance of a GaAs MESFET as an optical detector and as an optoelectronic mixer in analogue optical links

Noise measurements with a GaAs MESFET employed as a photodetector or as an optoelectronic mixer are reported. Despite its higher noise it is shown that with proper biasing the GaAs MESFET provided a higher carrier-to-noise ratio than a pin photodiode, and as an optoelectronic mixer provided a comparable signal-to-noise ratio to that of a conventional pin and microwave mixer combination. The implications of using GaAs MESFETs in these configurations are discussed.