Continuous Flow

Microbial fuel cells (MFCs) are biochemical-catalyzed systems in which electricity is produced by oxidizing biodegradable organic matters in presence of either bacteria or enzyme. This system can serve as a device for generating clean energy and, also wastewater treatment unit. In this paper, production of bioelectricity in MFC in batch and continuous systems were investigated. A dual chambered air–cathode MFC was fabricated for this purpose. Graphite plates were used as electrodes and glucose as a substrate with initial concentration of 30 g l−1 was used. Cubic MFC reactor was fabricated and inoculated with Saccharomyces cerevisiae PTCC 5269 as active biocatalyst. Neutral red with concentration of 200 μmol l−1 was selected as electron shuttle in anaerobic anode chamber. In order to enhance the performance of MFC, potassium permanganate at 400 μmol l−1 concentration as oxidizer was used. The performance of MFC was analyzed by the measurement of polarization curve and cyclic volatmmetric data as well. Closed circuit voltage was obtained using a 1 kΩ resistance. The voltage at steady-state condition was 440 mV and it was stable for the entire operation time. In a continuous system, the effect of hydraulic retention time (HRT) on performance of MFC was examined. The optimum HRT was found to be around 7 h. Maximum produced power and current density at optimum HRT were 1210 mA m−2 and 283 mW m−2, respectively.► Power generation was investigated in a single MFC at batch and continuous modes. ► Continuous MFCs offer some advantages over batch systems for practical applications. ► Polarity and cyclic voltammetry, were adopted to analyze experimental data. ► OCV was stable for the duration of 72 h of operation time in batch system. ► At optimum HRT (6.7 h), maximum output were 1210 mA m−2 and 283 mW m−2, respectively.

Most microbial electrolysis cells (MECs) contain only a single set of electrodes. In order to examine the scalability of a multiple-electrode design, we constructed a 2.5 L MEC containing 8 separate electrode pairs made of graphite fiber brush anodes pre-acclimated for current generation using acetate, and 304 stainless steel mesh cathodes (64 m2/m3). Under continuous flow conditions and a one day hydraulic

Continuous flow generation of Br 2 , Cl 2 and H 2 S coupled to a low-power 2.45 GHz microwave microstrip He plasma exiting from a capillary gas channel in a micro-fabricated sapphire wafer with microstrip lines has been used for the optical emission spectrometric determination ...

Shear-thinning fluids exhibit surprisingly rich behaviour. One example is the Kaye effect which occurs when a thin stream of a solution of polyisobutylene in Decalin is poured into a dish of the fluid. As pouring proceeds, a small stream of liquid occasionally leaps upward from the heap. This surprising effect, which lasts only a second or so, is named after its first observer A. Kaye, who could offer no explanation for this behaviour. Later, Collyer and Fischer suggested from 250 frames per second cine recordings that the fluid must be highly shear thinning as well as elastic and 'pituitous'. In addition, they concluded that a rigid surface is required to back the reflected liquid stream. While the words bouncing and reflection are associated with non-continuous and elastic effects, we will show here that the Kaye effect is in fact a continuous flow phenomenon. We show that the Kaye effect works for many common fluids, including shampoos and liquid soaps. We reveal its physical mechanism (formation, stability and disruption) through high-speed imaging. The measurements are interpreted with a simple theoretical model including only the shear thinning behaviour of the liquid; elastic properties of the liquid play no role. We show that the Kaye effect can be stable and that it can be directed. We even demonstrate a stable Kaye effect on a thin soap film excluding the necessity of a rigid backing surface.

Catalytic liquid-phase hydrogenation of aqueous nitrate solutions is presented as a potential, advanced treatment technology for the removal of excessive quantities of nitrate ions from polluted drinking water streams. Catalysts are briefly reviewed first, followed by mechanistic speculations and kinetics that have been proposed for the liquid-phase nitrate reduction. Subsequently, a novel process scheme consisting of integrated ion-exchange and catalytic

The objective of this study was to investigate the application of advanced oxidation processes (AOPs) to the treatment of wastewaters contaminated with hydrocarbon oil. Three different oil-contaminated wastewaters were examined and compared: (i) a ‘real’ hydrocarbon wastewater collected from an oil refinery (Conoco-Phillips Whitegate refinery, County Cork, Ireland); (ii) a ‘real’ hydrocarbon wastewater collected from a car-wash facility located at a petroleum filling station; and (iii) a ‘synthetic’ hydrocarbon wastewater generated by emulsifying diesel oil and water. The AOPs investigated were Fe2+/H2O2 (Fenton's reagent), Fe2+/H2O2/UV (Photo-Fenton's reagent) which may be used as an alternative to, or in conjunction with, conventional treatment techniques. Laboratory-scale batch and continuous-flow experiments were undertaken. The photo-Fenton parametric concentrations to maximize COD removal were optimized: pH = 3, H2O2 = 400 mg/L, and Fe2+ = 40 mg/L. In the case of the oil-refinery wastewater, photo-Fenton treatment achieved approximately 50% COD removal and, when preceded by physicochemical treatment, the percentage removal increased to approximately 75%.

This review highlights the many roles mass spectrometry plays in the discovery and development of new therapeutics by both the pharmaceutical and the biotechnology industries. Innovations in mass spectrometer source design, improvements to mass accuracy, and implementation of computer-controlled automation have accelerated the purification and characterization of compounds derived from combinatorial libraries, as well as the throughput of pharmacokinetics studies. The use of accelerator mass spectrometry, chemical reaction interface-mass spectrometry and continuous flow-isotope ratio mass spectrometry are promising alternatives for conducting mass balance studies in man. To meet the technical challenges of proteomics, discovery groups in biotechnology companies have led the way to development of instruments with greater sensitivity and mass accuracy (e.g., MALDI-TOF, ESI-Q-TOF, Ion Trap), the miniaturization of separation techniques and ion sources (e.g., capillary HPLC and nanospra...

Patterns of dry season surface flow in forested headwater channels of southwest Washington were observed during August to September 2001 and July to October 2002. In 2001, 17 channels were sampled once, and the uppermost points of continuous flow (CF) and surface water (SW) were located. In 2002, sampling was replicated three to five times at each of 21 channels. Annual and seasonal data suggested that the location of SW varied less than CF. In most channels, SW remained at or near the channel head year around. The pattern of surface flow between CF and the channel head was used to test alternative hypotheses describing dry season recession patterns: (A) surface flow consistently retreats in a downstream direction, and (B) flow comes from fixed sources along the channel, thus surface flow retreats up-channel towards these sources. The dominant surface flow spatial pattern in streams less than 30 percent slope was increased intermittency without a clear pattern of retreat, and thus inconsistent with either hypothesis. High gradient channels (> 30 percent slope) exhibited a combination of increased intermittency, and extensive upward retreats of surface water consistent with Hypothesis B. Differences between 2001 and 2002 suggest late summer flows in small headwater basins were controlled by spring precipitation, rather than the typically greater winter precipitation.

Experimental variables in continuous flow hydride generation inductively coupled plasma-optical emission spectrometry (CF-HG-ICP-OES) were optimized for determination of bismuth. Concentrations of NaBH4, HCl, and NaOH, flow rates of NaBH4, sample solution, waste and carrier argon, radio frequency power, lengths of reaction, and stripping coils were optimized to obtain lower detection limits. Under optimum conditions, the detection limit was calculated as 0.16 ng mL−1, and the calibration plot was linear between 1.0–50.0 ng mL−1. An improvement in detection limit of 5.75 times by CF-HG-ICP-OES was reached vs. ICP-OES. Relative standard deviation (RSD) for ten replicate measurements of 10.0 ng mL−1 Bi was calculated as 3.9%. Effect of possible interferic ions on Bi signal was evaluated. Accuracy of method was verified by using a standard reference material, SRM 1643e. Results found for Bi were in satisfactory agreement with certified values. The proposed method was then employed to determine trace concentration of Bi in milk samples. Bi amounts in samples were found in the range from lower than the quantitation limit to 14.5 ng mL−1, whereas Bi concentrations were lower than the detection limit in three samples.

In the pharmaceutical industry, systems for improving operational effectiveness and efficiency are becoming more and more popular. In this paper, developments in the industry’s improvements in operational effectiveness and efficiency have been analyzed. A holistic model is presented which builds the basis for the presented study results. The study includes data gathered from pharmaceutical production sites in surveys in 2004 and 2009. The analysis is divided according to the four sub-systems: Total Productive Maintenance, Total Quality Management, Just-in-Time, and the Management System. For each sub-system, key performance indicators and associated elements (practices and instruments) from 2004 to 2009 are investigated. The data indicates that the industry did make continuous steps towards “Excellence in Operations” between 2004 and 2009. Pharmaceutical companies took control over their former low asset utilization and managed to improve the efficiency of their quality systems; however, they are still far away from having any kind of “continuous flow”, smooth production scheduling or make-to-order manufacturing. It can be said that most of the companies are still working on the effectiveness side rather than focusing on the efficiency side.