Parallel Test System Research Articles

Biodegradation Kinetics of Fragrances, Plasticizers, UV Filters, and PAHs in a Mixture─Changing Test Concentrations over 5 Orders of Magnitude.

Biodegradation of organic chemicals emitted to the environment is carried out by mixed microbial communities growing on multiple natural and xenobiotic substrates at low concentrations. This study aims to (1) perform simulation type biodegradation tests at a wide range of mixture concentrations, (2) determine the concentration effect on the biodegradation kinetics of individual chemicals, and (3) link the mixture concentration and degradation to microbial community dynamics. Two hundred ninety-four parallel test systems were prepared using wastewater treatment plant effluent as inoculum and passive dosing to add a mixture of 19 chemicals at 6 initial concentration levels (ng/L to mg/L). After 1-30 days of incubation at 12 °C, abiotic and biotic test systems were analyzed using arrow solid phase microextraction and GC-MS/MS. Biodegradation kinetics at the highest test concentrations were delayed for several test substances but enhanced for the reference chemical naphthalene. Test concentration thus shifted the order in which chemicals were degraded. 16S rRNA gene amplicon sequencing indicated that the highest test concentration (17 mg C/L added) supported the growth of the genera Acidovorax, Novosphingobium, and Hydrogenophaga, whereas no such effect was observed at lower concentrations. The chemical and microbial results confirm that too high mixture concentrations should be avoided when aiming at determining environmentally relevant biodegradation data.

New Products

Keysight Technologies, Inc. has introduced the new i7090 massively parallel board test system. This is a new category of automated test equipment designed to perform tests in parallel, on multiple printed circuit board assemblies (PCBA), to achieve high volume throughput which speeds time-to-market and reduces cost-of-test.

High-Performance Binary Protein Interaction Screening in a Microfluidic Format

The standard procedure to increase microfluidic chip performance is to grow the number of parallel test systems on the chip. This process is accompanied by miniaturizing biochemical workflows and micromechanical elements, which is often a major challenge for both engineering fields. In this work, we show that it is possible to substantially increase the runtime performance of a microfluidic affinity assay for protein interactions by simultaneously engineering fluid logics and assay chemistry. For this, synergistic effects between the micro- and chemical architecture of the chip are exploited. The presented strategy of reducing the runtime rather than size and volume of the mechanical elements and biological reagent compartments will, in general, be of importance for future analytical test systems on microfluidic chips to overcome performance barriers.

Robust High-Performance Inverter Control Using Discrete Direct-Design Pole Placement

A robust high-performance discrete controller, with a simple implementation and characterizable performance that lend it to high-power industrial applications, is proposed. Discrete direct-design pole placement allows the use of common design parameters such as damping ratio and bandwidth (BW) to define the controller's response. High performance is demonstrated with example systems achieving BWs twice as high as those of traditional cascaded current- and voltage-loop controllers. The controller is shown to be robust against component variations and many different load types, including low-impedance grid connections. Comparisons between the proposed controller and a discretized full-state-feedback continuous-time-derived controller are made and show significant improvements in both BW and stability margins. Practical tests on a parallel 2-MVA test system demonstrate a close correlation with the analysis, with an error of less than 1%.

New closure method for a simultaneous diazo coupling between 1- and 2-Naphthols and diazotized sulphanilic acid

New closure method for a simultaneous diazo coupling between 1- and 2-Naphthols and diazotized sulphanilic acid This paper presents the effects of mixing on the course of complex chemical reactions in relation to the manufacturing of pure products at high reaction selectivity, and designing mixing strategies using complex, homogeneous test reaction systems. As an example, the competitive-consecutive and parallel reaction test system including a simultaneous diazo-coupling between 1- and 2-naphtols and diazotized sulphanilic acid is considered. The effect of mixing on the reaction selectivity is interpreted using mechanistic modeling and a new closure scheme. The new closure represents an extension of the conditional PDF closure applied before to simple reaction schemes.

Integration of desalinated seawater into a distribution system: A corrosion pilot study

A proposed seawater desalination plant for Carlsbad, Calif., will produce treated water that varies from the city—s typical imported surface water supply. A six‐month pilot study was conducted to compare how Carlsbad distribution materials would be affected by the potential corrosion that might arise from conditioned desalinated seawater versus the city—s typical supply. Various distribution and home plumbing appurtenances were evaluated in parallel test systems, including copper pipe, brass service meters, cement‐mortar‐lined pipe, and cast‐iron distribution system gate valves. Corrosion was assessed by analyzing changes in water quality caused by pipe corrosion or passivation, including metal concentration (iron, zinc, lead, copper, and aluminum), calcium, alkalinity, and turbidity changes. Pilot testing demonstrated that conditioned reverse osmosis permeate achieving minimum water quality goals—alkalinity of 45 mg/L as calcium carbonate (CaCO3), hardness of 40 mg/L as CaCO3, and pH of 8.5—was not likely to trigger new corrosion problems in the Carlsbad distribution system.

High-cycle fatigue of micromachined single-crystal silicon measured using high-resolution patterned specimens

A single-crystal silicon fatigue test structure was fabricated using high-resolution lithography to improve smoothness and morphological uniformity. An on-chip test structure, including a notched test piece, a resonator, an electrostatic actuator and a deflection sensor, was fabricated using 0.6 µm resolution lithography. Fatigue tests were performed under different deflection amplitudes and humidity conditions. The lifetime scattering was limited nearly within 1 order at each condition, and this was a large improvement over other reported studies. Our test results indicated a clear tendency for the lifetime to lengthen when the strain amplitude or ambient humidity was decreased. Strain–life behaviors at two different humidity conditions were analyzed using Paris law and crack propagation exponents of 19.6 and 23.0 were obtained at 50%RH and 25%RH, respectively. A humidity dependence was clearly confirmed by the results of our low-scattering experiment. Moreover, for this measurement, a new parallel test system was built in which fatigue tests on up to 12 samples could be performed simultaneously. The drive circuit, which enables a deflection-controlled fatigue test, is described and its performance was demonstrated.

High-cycle fatigue of micromachined single crystal silicon measured using a parallel fatigue test system

Fatigue testing of micromachined single-crystal silicon was performed using a test system that allowed simultaneous testing of multiple samples. The on-chip test structure, including an actuator, was fabricated using 0.6µm resolution lithography to improve the morphological uniformity of the samples. Fatigue test results exhibited a clear tendency for the lifetime to lengthen when the strain amplitude or ambient humidity was decreased. The strain-life relationship at 50%RH was analyzed using the Paris law, and a crack propagation exponent of 19 was obtained.

The use of simultaneous chemical precipitation in modified activated sludge systems exhibiting biological excess phosphate removal: Part 5: Experimental periods using a ferrous-ferric chloride blend

A blend of ferrous chloride and ferric chloride (FeCl2-FeCl3) was simultaneously dosed into an activated sludge system at pilot scale in order to test the effect on biological P removal. Additional removal due to chemical precipitation was measured as the difference in system P removal between parallel test and control systems. Both systems strongly exhibited biological excess P removal (BEPR). The extent of P release in the anaerobic reactors of the two systems was compared by mass balance, as one indicator of the relative "magnitude" of BEPR. Phosphorus fractionation of the mixed liquor also served as an indicator of the biological and chemical mechanisms. Evidence was found that the BEPR mechanism is partially inhibited by simultaneous FeCl2-FeCl3 addition, even in the absence of effluent phosphate limitation. However, the degree of inhibition was relatively low, ranging from 3 to 25% (approximately) for Fe doses in the range ca. 10 to 20 mg/ℓ as Fe, with an average system P removal of 14 to 18 mgP/ℓ in the control. FeCl2-FeCl3 dosing in this range was sufficient to produce additional P removal of the order of 1 to 8 mgP/ℓ over periods of one to seven sludge ages per experimental period, depending on the experimental conditions. Sustained operation of the BEPR mechanism in the presence of FeCl2-FeCl3 was possible over a continuous period of seven sludge ages, under conditions in which effluent phosphate was at least partially limiting. Under such conditions, the chemical and biological mechanisms appear to be "disadvantaged" to approximately the same extent, as evidenced by the apparent stoichiometry of Fe: P for the chemical precipitation and magnitude of the poly P containing fractions measured for the biological mechanism. This suggested that the biological mechanism is able to compete effectively with the chemical mechanism under conditions of low reactor phosphate concentrations (~1 mgP/ℓ orthoP) for sustained periods. However, the presence of simultaneous chemical precipitant significantly reduces the extent to which the biological P removal potential is utilised under P-limiting conditions. This could explain the difficulty sometimes reported in the control of full-scale activated sludge systems with simultaneous precipitant addition where a very low effluent P concentration WaterSA Vol.27(2) 2001: 117-134