Schnelle Bestimmung von Furfurol und Hydroxymethylfurfurol in alkoholischen Getr?nken mit Hilfe der Umkehrphasen-Chromatographie

Zusammenfassung Furfurol und Hydroxymethylfurfurol können leicht mit Hilfe der Umkehrphasen-Chromatographie in Alkoholika bestimmt werden. Eine Probenvorbereitung ist nicht notwendig. Die beiden Aldehyde werden UV-spektrometrisch erfaßt, die absolute Nachweisgrenze bei Routinearbeiten beträgt 4–7 mg/100 l reinen Alkohol (entsprechend 0,01–0,03 mg/l im Getränk) und kann für Spurenbestimmungen auf 0,002–0,001 mg/l durch Injektion von größeren Probenvolumen erniedrigt werden. Die Peakhöhen der beiden Furfuroie sind im Bereich von 0,25–3 mg/l Getränk linear von der Konzentration abhängig. Die Gesamtanalyse dauert etwa 12 min. Mit der beschriebenen Methode werden brasilianischer Zukkerrohrschnaps (Cachaça) Bowie eine Reihe in Deutschland käuflicher Alkoholika untersucht.

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Rapid determination of furfural and hydroxymethylfurfural in alcoholic beverages by reverse-phase-chromatographyComparative investigations on the content of furfurals in Brazilian Cachaça and other alcoholic liquors

Summary Furfural and Hydroxymethylfurfural can easily be determined in alcoholic beverages by means of reverse phase chromatography. A special sample preparation is not necessary. The aldehydes are detected by UV-spectrometry, the absolute detection limit in routine work is 4–7 mg/100 liters of pure ethanol (corresponding to 0.016–0.03 mg/l beverage) and can be extended down to 0.002–0.001 mg/l when injecting higher volumes for trace analysis. In the range of 0.25–3 mg/l linear relationship is obtained between peak hight and concentration. The complete assay procedure takes about 12 min. A series of Brazilian Cachaça samples and German commercial liquors were investigated with the here described method.

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Sumário Os autores apresentam um método de determinação de Furfural e Hidroxi-metilfurfural em cachaça e outras bebidas alcoolicas, Cromatografia em alta pressão com colunas de fase reversa (C₈; 5 m; 250 × 4 mm; CH₃CN/H₂O 5/95 como eluente) permite a separação e determinaçã sem pre-tratamento das amostras em 10–12 minutos. A sensibilidade da determinação em UV (254 nm) è 4–7 mg/100 L álcool puro (0.01–0.03 mg/L na bebida respectivamente). Usando um volume maior de injecção, o limite se pode abaixar até 0.002–0.001 mg/L bebida. A altura dos picos é proporçional à concentração entre 0.25–3 mg/L bebida. As cachaças investigadas possuem geralmente um conteúdo de Furfural e de Hidroxi-metilfurfural menor do que suposto e determinato pelo método de anilina recomendado pelo governo (determinação não específica).

     

ESA-based in-fiber nanocavity for hydrogen-peroxide detection

A fiber-optic sensor sensitive to hydrogen peroxide has been designed based on the electrostatic layer-by-layer self-assembly method. Prussian blue has been deposited in a polymeric structure formed by Poly(allylamine hydrochloride) and poly(acrylic acid). The concentration that can be detected range between 10/sup -6/-10/sup -3/ M, and recovery of the sensor after immersion into a reductive agent was demonstrated. The response of the sensor is independent of the pH for values that range between 4-7.4. Some rules for estimation of the refractive index of the material deposited and the thickness of the bilayers are also presented.     

The availability of source code in relation to timely response to security vulnerabilities

Once a vulnerability has been found in an application or service that runs on a computer connected to the Internet, fixing that exploit in a timely fashion is of the utmost importance. There are two parts to fixing vulnerability: a party acting on behalf of the application's vendor gives instructions to fix it or makes a patch available that can be downloaded; then someone using that information fixes the computer or application in question. This paper considers the effects of proprietary software versus non-proprietary software in determining the speed with which a security fix is made available, since this can minimize the amount of time that the computer system remains vulnerable.     

Energetic ion loss detector on the Alcator C-Mod tokamak

A scintillator-based energetic ion loss detector has been successfully commissioned on the Alcator C-Mod tokamak. This probe is located just below the outer midplane, where it captures ions of energies up to 2 MeV resulting from ion cyclotron resonance heating. After passing through a collimating aperture, ions impact different regions of the scintillator according to their gyroradius (energy) and pitch angle. The probe geometry and installation location are determined based on modeling of expected lost ions. The resulting probe is compact and resembles a standard plasma facing tile. Four separate fiber optic cables view different regions of the scintillator to provide phase space resolution. Evolving loss levels are measured during ion cyclotron resonance heating, including variation dependent upon individual antennae.     

Layout and results from the initial operation of the high-resolution x-ray imaging crystal spectrometer on the Large Helical Device

First results of ion and electron temperature profile measurements from the x-ray imaging crystal spectrometer (XICS) diagnostic on the Large Helical Device (LHD) are presented. This diagnostic system has been operational since the beginning of the 2011 LHD experimental campaign and is the first application of the XICS diagnostic technique to helical plasma geometry. The XICS diagnostic provides measurements of ion and electron temperature profiles in LHD with a spatial resolution of 2 cm and a maximum time resolution of 5 ms (typically 20 ms). Ion temperature profiles from the XICS diagnostic are possible under conditions where charge exchange recombination spectroscopy (CXRS) is not possible (high density) or is perturbative to the plasma (low density or radio frequency heated plasmas). Measurements are made by using a spherically bent crystal to provide a spectrally resolved 1D image of the plasma from line integrated emission of helium-like Ar(16 +). The final hardware design and configuration are detailed along with the calibration procedures. Line-integrated ion and electron temperature measurements are presented, and the measurement accuracy is discussed. Finally central temperature measurements from the XICS system are compared to measurements from the Thomson scattering and CXRS systems, showing excellent agreement.     

Statistical testing for sufficient control chart performances during monitoring of grouped processes

With ISO 7870-8, a standardized application of charting techniques for short runs and small mixed batches was presented in 2017. Similar to various scientific approaches, it requires that sample values from grouped processes follow nearly identical distributions. In practice, however, there tend to be differences between distribution parameters. Moreover, equal parameters do not ensure that distributions are properly aligned to the center line and control limits of the chart. These facts can lead to undesired control chart performances which can be expressed by average run lengths (ARL) during in-control and out-of-control conditions. In this work, a statistical test for sufficient control chart performances during monitoring of grouped processes based on preliminary samples is proposed. Control chart performances are defined as sufficient when they deviate within acceptable ranges from usual performances during single process monitoring in mass production. The ARL resulting from estimated distributions and planned production sequences is used as test statistic and calculated via the Markov chain approach. Exemplary tests are executed for scenarios with individuals and cumulated sum (CUSUM) charts. A simulative determination of error rates resulting from the ARL-based testing demonstrates its effectiveness in testing for sufficient control chart performances compared to an indirect testing with Levene's test and a one-way analysis of variance (ANOVA).     

One‐Step Formulation of Protein Microparticles with Tailored Properties: Hard Templating at Soft Conditions

Formulation of therapeutic proteins into particulate forms is a main strategy for site‐specific and prolonged protein delivery as well as for protection against degradation. Precise control over protein particle size, dispersity, purity, as well as mild preparation conditions and minimal processing steps are highly desirable. It is, however, hard to fit all these criteria with conventional preparation techniques. Here a one‐step hard‐templating synthesis of microparticles composed of functional, non‐denatured protein is reported. The method is based on filling porous CaCO₃ microtemplates with the protein near to its isoelectric point (pI) followed by pH‐ or EDTA‐mediated dissolution of the tempplates. In principle, a wide variety of proteins can be converted into microparticles using this approach. The main requirement is an overlap of the protein insolubility and a template solubility for a certain parameter (here pH or EDTA). Here the formulation of insulin particles is studied in detail and it is shown that particles consisting of high molecular weight protein (catalase) can also be prepared. In this context, the synthesis of CaCO₃ templates with controlled size, the mechanism of the protein microparticle formation and mechanical properties of the microparticles are discussed. For the first time, the fabrication of mesoporous monodispersed CaCO₃ microtemplates with identical porocity but tuned diameter from 3 to 20 μm is demonstrated. The protein particle diameter can be adjusted by choosing the appropriate template size that is critical for successful pulmonary delivery of insulin. As a first step towards insulin delivery, the in vitro release of insulin at physiological conditions is studied.     

Numerical simulation of molten pool dynamics in high power disk laser welding

A single-phase problem is solved rather than a multiphase problem for numerical simplicity: and the solution is based on the assumption that the region of gas or plasma can be treated as a void because solid or liquid steel has a greater density level than gas or plasma. The volume-of-fluid method, which can calculate the free surface shape of the keyhole, is used in conjunction with a ray-tracing algorithm to estimate the multiple reflections. Fresnel's reflection model is simplified by the Hagen-Rubens relation for handling a laser beam interaction with materials. Factors considered in the simulations include buoyancy force, Marangoni force and recoil pressure; furthermore, pore generation is simulated by means of an adiabatic bubble model, which can also lead to the phenomenon of a keyhole collapse. Models of the shear stress on the keyhole surface and of the heat transfer to the molten pool via a plasma plume are introduced in simulations of the weld pool dynamics. Analysis of the temperature profile characteristics of the weld bead and molten pool flow in the molten pool is based on the results of the numerical simulations. The simulation results are used to estimate the weld fusion zone shape; and the results of the simulated fusion zone formation are compared with the results of the experimental fusion zone formation and found to be in good agreement. The effects of laser beam profile (Gaussian vs. measured), vapor shear stress, vapor heat source and sulfur content on the molten pool behavior and fusion zone shape are analyzed.     

On the exciton profile in OLEDs-seamless optical and electrical modeling

We present a comprehensive model to simulate organic light-emitting devices (OLEDs) that includes a seamless coupling of charges, excitons and photons. The comprehensive model accounts for the position dependent exciton lifetime due to the optical environment in the multilayer OLED structures. We first study the effect of different charge mobilities and quantum efficiencies of the light-emitting material on the exciton profiles. Moreover, we discuss the extension of an optical model to account for the exciton dynamics. This comprehensive optical model is validated and justified on the basis of consistency checks. Namely, we show that our comprehensive optical model can take the cavity effects as seen in simulation results of the comprehensive electrical model into account. The advantage of the comprehensive optical model is a quick and accurate insight into the exciton physics if applied together with a nonlinear least square (NLSQ) fitting method. Finally, we apply the comprehensive optical model with the NLSQ-method in order to extract the exciton profiles from emission spectra of a blue light-emitting polymer diode (PLED) measured at different current levels.