Tar analysis from biomass gasification by means of online fluorescence spectroscopy

Optical methods in gas analysis are very valuable mainly due to their non-intrusive character. That gives the possibility to use them for in-situ or online measurements with only optical intervention in the measurement volume. In processes like the gasification of biomass, it is of high importance to monitor the gas quality in order to use the product gas in proper machines for energy production following the restrictions in the gas composition but also improving its quality, which leads to high efficient systems. One of the main problems in the biomass gasification process is the formation of tars. These higher hydrocarbons can lead to problems in the operation of the energy system. Up to date, the state of the art method used widely for the determination of tars is a standardized offline measurement system, the so-called “Tar Protocol”. The aim of this work is to describe an innovative, online, optical method for determining the tar content of the product gas by means of fluorescence spectroscopy. This method uses optical sources and detectors that can be found in the market at low cost and therefore it is very attractive, especially for industrial applications where cost efficiency followed by medium to high precision are of high importance.     

Elimination of motion,pulsatile flow and cross-talk artifacts using blade sequences in lumbar spine MR imaging

The purpose of this study is to evaluate the ability of T2 turbo spin echo (TSE) axial and sagittal BLADE sequences in reducing or even eliminating motion, pulsatile flow and cross-talk artifacts in lumbar spine MRI examinations. Forty four patients, who had routinely undergone a lumbar spine examination, participated in the study. The following pairs of sequences with and without BLADE were compared: a) T2 TSE Sagittal (SAG) in thirty two cases, and b) T2 TSE Axial (AX) also in thirty two cases. Both quantitative and qualitative analyses were performed based on measurements in different normal anatomical structures and examination of seven characteristics, respectively. The qualitative analysis was performed by experienced radiologists. Also, the presence of image motion, pulsatile flow and cross-talk artifacts was evaluated. Based on the results of the qualitative analysis for the different sequences and anatomical structures, the BLADE sequences were found to be significantly superior to the conventional ones in all the cases. The BLADE sequences eliminated the motion artifacts in all the cases. In our results, it was found that in the examined sequences (sagittal and axial) the differences between the BLADE and conventional sequences regarding the elimination of motion, pulsatile flow and cross-talk artifacts were statistically significant. In all the comparisons, the T2 TSE BLADE sequences were significantly superior to the corresponding conventional sequences regarding the classification of their image quality. In conclusion, this technique appears to be capable of potentially eliminating motion, pulsatile flow and cross-talk artifacts in lumbar spine MR images and producing high quality images in collaborative and non-collaborative patients.     

Dielectric‐loaded plasmonic waveguide components: Going practical

Surface plasmon propagating modes supported by metal/dielectric interfaces in various configurations can be used for radiation guiding similarly to conventional dielectric waveguides. Plasmonic waveguides offer two attractive features: subdiffraction mode confinement and the presence of conducting elements at the mode‐field maximum. The first feature can be exploited to realize ultrahigh density of nanophotonics components, whereas the second feature enables the development of dynamic components controlling the plasmon propagation with ultralow signals, minimizing heat dissipation in switching elements. While the first feature is yet to be brought close to the domain of practical applications because of high propagation losses, the second one is already being investigated for bringing down power requirements in optical communication systems. In this review, the latest application‐oriented research on radiation modulation and routing using thermo‐optic dielectric‐loaded plasmonic waveguide components integrated with silicon‐based photonic waveguides is overviewed. Their employment under conditions of real telecommunications is addressed, highlighting challenges and perspectives.     

Asymptotic behaviour of the stochastic Lotka-Volterra model

This paper examines the asymptotic behaviour of the stochastic extension of a fundamentally important population process, namely the Lotka-Volterra model. The stochastic version of this process appears to have far more intriguing properties than its deterministic counterpart. Indeed, the fact that a potential deterministic population explosion can be prevented by the presence of even a tiny amount of environmental noise shows the high level of difference which exists between these two representations.     

Lateral flow devices for nucleic acid analysis exploiting quantum dots as reporters

There is a growing interest in the development of biosensors in the form of simple lateral flow devices that enable visual detection of nucleic acid sequences while eliminating several steps required for pipetting, incubation and washing out the excess of reactants. In this work, we present the first dipstick-type nucleic acid biosensors based on quantum dots (QDs) as reporters. The biosensors enable sequence confirmation of the target DNA by hybridization and simple visual detection of the emitted fluorescence under a UV lamp. The ‘diagnostic’ membrane of the biosensor contains a test zone (TZ) and a control zone (CZ). The CZ always fluoresces in order to confirm the proper function of the biosensor. Fluorescence is emitted from the TZ, only when the specific nucleic acid sequence is present. We have developed two general types of QD-based nucleic acid biosensors, namely, Type I and Type II, in which the TZ consists of either immobilized streptavidin (Type I) or immobilized oligodeoxynucleotides (Type II). The control zone consists of immobilized biotinylated albumin. No purification steps are required prior to the application of the DNA sample on the strip. The QD-based nucleic acid biosensors performed accurately and reproducibly when applied to (a) the visual detection of PCR amplification products and (b) visual genotyping of single nucleotide polymorphisms (SNPs) in human genomic DNA from clinical samples. As low as 1.5 fmol of double-stranded DNA were clearly detected by naked eye and the dynamic range extended to 200 fmol. The %CV were estimated to be 4.3–8.2.     

Future perspectives for the advancement of electrochemical hydrogen peroxide production

Hydrogen peroxide (H₂O₂)is an important chemical with multiple uses across domestic and industrial settings. With a global need for wider adoption of green synthetic methods, there has been a growing interest in the electrochemical synthesis of H₂O₂ from oxygen reduction or water oxidation. State-of-the-art catalyst and reactor developments are beginning to advance to a stage where electrochemical synthesis is discussed as a viable alternative to current industrial methods. In this review, we highlight some of the most promising candidates for H₂O₂ electrosynthesis technologies and what further advancements are needed before the electrochemical route could challenge the ubiquitous anthraquinone process.     

Performance Monitoring and Competence Assessment in Health Services

Health and health service monitoring is among the most promising research area today and the world work towards efficient and cost effective health care. This paper deals with monitoring health service performance using more than one performance outcome variable (multi-attribute processes), which is common in most health services. Although monitoring whether a health service changes or improves over time is important this is well covered in the current literature. Therefore this paper focuses on comparing similar health services in terms of their performance. The proposed procedure is based on an appropriate control chart. The paper deals with firstly the case when no risk adjustment is required because the health services being compared treat the same patient case-mix which does not vary over time. Secondly it deals with comparing health services where risk adjustment is required because the patient case-mix they service do differ because they service either very different geographical locations or service very different demographics of the same population. The technology developed in this paper could be used for example to assess and compare health practitioners’ competence over time, i.e. to decide if two doctors are equivalent in terms of their outcome performances. The waiting time random variable associated with the run length distribution of the control charts (as well as to competence testing) is studied using a Markov Chain embedding technique. Numerical results are provided that exhibit the value of the proposed procedures.     

Budgeting fuel consumption in a cruise liner

An equation to be used to budget fuel consumption in a cruise liner is developed. The model building process is described in detail to explain the way in which the results were obtained.     

Eine einfache Methode zur Bestimmung von Cadmium in Harn

Zusammenfassung Cadmium bildet negativ geladene Jodidkomplexe, die eine Abtrennung dieses Elementes aus dem Harn mit Hilfe eines Anionen-austauschers ermöglichen. Elution vom Austauscher ergibt eine Cadmiumlösung mit nur wenigen Begleitstoffen bzw. einer einheitlichen Matrix, die für eine weitgehend störungsfreie Endbestimmung durch flammenlose Atomabsorptionsspektrometrie verwendet werden kann. Danach beträgt der Normalgehalt an Cadmium im Harn im Mittel 0,78±0,53 ng/ml und liegt im Bereich zwischen 0,22 und 1,7 ng/ml.

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A simple method for determination of cadmium in urine

Summary Cadmium can be isolated from urine by formation of negatively charged iodide complexes bound to an anion exchange resin. Elution from the resin gives a cadmium solution with only a few concomitant substances in an uniform matrix. Thus an undisturbed determination by flameless atomic absorption spectrometry is achieved. The mean of the natural cadmium level found in urine was 0.78±0.53 ng/ml, within the normal range between 0.22 and 1.7 ng/ml.

     

157-nm Laser ablation of polymeric layers for fabrication of biomolecule microarrays

A new methodology for protein microarray fabrication is proposed based on the ablation of polymer film using laser at 157 nm (F₂). The polymer has been selected among others with the criterion of negligible protein adsorption. Improved results have been obtained by pretreatment of the polymer surface with an inert protein. The use of 157-nm laser radiation allowed very good depth control during the polymeric layer ablation process. In addition the importance of laser ablation at 157 nm is based on the fact that irradiated surfaces indicate limited chemical change due to the fact that laser ablation at 157 nm is only photochemical, thus avoiding excessive surface heating and damage. Results of protein microarray fabrication are presented to illustrate the viability of the proposed method.