Removal of dimethylsulfide, n-hexane and toluene from waste air in a flat membrane bioreactor under continuous conditions

Dimethylsulfide (DMS), n-hexane and toluene removal from a waste air was carried out by using a flat composite membrane bioreactor under continuous feeding conditions. The composite membrane consisted of a dense polydimethylsiloxane top layer with an average thickness of 1.5 μm supported with a porous polyacrylonitrile layer of 50 μm. The membrane bioreactor (MBR) was operated during 9 months in which several operational conditions were applied. The inlet load of each compound ranged from 0 to 350 g m-3 h-1 and removal efficiencies of 80, 70 and 0 to 30 % were reached for DMS, toluene and hexane respectively. Two different empty bed residence time (EBRT) were applied on the MBR in order to check the influence of the residence time on the reactor performance. In this case, DMS and toluene removal increased with an increasing EBRT, while the removal of hexane remained constant. By increasing the flow rate of the recirculated liquid from 22 l min-1 to 45 l min-1, the total performance of the biofilter decreased. To increase the mass transfer of hexane in order to get a higher removal, an emulsion of water/silicone oil 80/20 V% was used as recirculated medium at the liquid side of the reactor. This caused a decrease in DMS removal while the removal of toluene remained constant. The variation on the hexane removal decreased significantly, so the reactor became more reliable for degrading hexane

Gold nanoparticle coated silicon nitride chips for intracellular surface-enhanced raman spectroscopy

Using surface-enhanced Raman spectroscopy on gold-nanoparticle-decorated silicon nitride chips, we monitor the release of dextran-rhodamin molecules from capsules inside living cells. This demonstrates the feasibility of using photonic chips for intracellular sensing at visible wavelengths

Autoencoders for strategic decision support

In the majority of executive domains, a notion of normality is involved in most strategic decisions. However, few data-driven tools that support strategic decision-making are available. We introduce and extend the use of autoencoders to provide strategically relevant granular feedback. A first experiment indicates that experts are inconsistent in their decision making, highlighting the need for strategic decision support. Furthermore, using two large industry-provided human resources datasets, the proposed solution is evaluated in terms of ranking accuracy, synergy with human experts, and dimension-level feedback. This three-point scheme is validated using (a) synthetic data, (b) the perspective of data quality, (c) blind expert validation, and (d) transparent expert evaluation. Our study confirms several principal weaknesses of human decision-making and stresses the importance of synergy between a model and humans. Moreover, unsupervised learning and in particular the autoencoder are shown to be valuable tools for strategic decision-making

Gold nanodome-patterned microchips for intracellular surface-enhanced Raman spectroscopy

While top-down substrates for surface-enhanced Raman spectroscopy (SERS) offer outstanding control and reproducibility of the gold nanopatterns and their related localized surface plasmon resonance, intracellular SERS experiments heavily rely on gold nanoparticles. These nanoparticles often result in varying and uncontrollable enhancement factors. Here we demonstrate the use of top-down gold-nanostructured microchips for intracellular sensing. We develop a tunable and reproducible fabrication scheme for these microchips. Furthermore we observe the intracellular uptake of these structures, and find no immediate influence on cell viability. Finally, we perform a proof-of-concept intracellular SERS experiment by the label-free detection of extraneous molecules. By bringing top-down SERS substrates to the intracellular world, we set an important step towards time-dependent and quantitative intracellular SERS

On-chip enhanced raman spectroscopy using metal slot waveguide

info:eu-repo/semantics/publishe

Nanophotonic waveguide enhanced Raman spectroscopy of biological submonolayers

Characterizing a monolayer of biological molecules has been a major challenge. We demonstrate nanophotonic wave-guide enhanced Raman spectroscopy (NWERS) of monolayers in the near-infrared region, enabling real-time measurements of the hybridization of DNA strands and the density of sub-monolayers of biotin-streptavidin complex immobilized on top of a photonics chip. NWERS is based on enhanced evanescent excitation and collection of spontaneous Raman scattering near nanophotonic waveguides, which for a one centimeter silicon nitride waveguide delivers a signal that is more than four orders of magnitude higher in comparison to a confocal Raman microscope. The reduced acquisition time and specificity of the signal allows for a quantitative and real-time characterization of surface species, hitherto not possible using Raman spectroscopy. NWERS provides a direct analytic tool for monolayer research and also opens a route to compact microscope-less lab-on-a-chip devices with integrated sources, spectrometers and detectors fabricated using a mass-producible CMOS technology platform

Silicon-nitride waveguides for on-chip Raman spectroscopy

The evanescent tail of the guided modes can efficiently excite Raman active molecules located in the cladding of a waveguide. Similarly, a significant fraction of the total emitted Stokes power is evanescently coupled to the same mode. Further, the enhancement effects inherent to the waveguide, alongside with the long interaction length, lead to an increased light-matter interaction, resulting in a higher sensitivity as required by spectroscopic applications, especially in the context of Raman spectroscopy. We calculate the spontaneous Raman scattering efficiency as a function of siliconnitride strip waveguide dimensions and show that under typical conditions, the overall efficiency is approximately two orders of magnitude higher than in confocal configuration in the free space. We also report the experimental demonstration of the use of silicon-nitride based photonic waveguides in a lab-on-a-chip context for Raman spectroscopy. To the best of our knowledge, this is the first demonstration of Raman spectroscopy using photonic waveguides