In situ visualization of flow and fouling layer formation in ceramic hollow fiber membranes by magnetic resonance imaging (MRI)

Within membrane processes, fouling is one of the critical issues affecting the productivity, plant operation and maintenance costs. Focusing on wastewater treatment processes, it has been reported that extracellular polymeric substances (EPS) are one of the main causes of membrane fouling. In membrane filtration research, sodium alginate often serves as a model compound for EPS. Sodium alginate is a hydrophilic unbranched binary copolymer. In the presence of divalent cations, e.g. Ca2+, alginates form complexes, which lead to a significant change in filtration mechanisms in dead-end filtration and also to a change in filtration performance during cross-flow filtration experiments. Filtration conditions (e.g. transmembrane pressure or cross flow velocity), feed composition as well as membrane material have a major influence on the fouling behavior of the system. In this study ceramic hollow fiber membranes were used due to their high chemical and thermal stability coupled with a high specific membrane surface. In addition to the evaluation of the filtration data using conventional cake filtration model, nuclear magnetic resonance imaging was used to elucidate the influence of Ca2+ on the fouling layer structure for alginate filtration with ceramic hollow fiber membranes. In order to visualize the alginate layers inside the opaque ceramic hollow fiber membranes by means of MRI, specific contrast agents were applied. Supplementary to multi slice multi echo imaging, flow velocity measurements were performed to gain more insight into the hydrodynamics in the fouled membranes. MRI reveals the structure of the alginate layers and confirms the assumption obtained from the evaluation of filtration data, that the addition of Ca2+ is leading to the formation of an alginate gel layer on the membrane, whereas in the absence of Ca2+, the structure of the alginate layer is rather of concentration polarization manner, hence more fluid and hydrodynamically better controllable

A smart archive box for museum artifact monitoring using battery-less temperature and humidity sensing

For the first time, this paper reports a smart museum archive box that features a fully integrated wireless powered temperature and humidity sensor. The smart archive box has been specifically developed for microclimate environmental monitoring of stored museum artifacts in cultural heritage applications. The developed sensor does not require a battery and is wirelessly powered using Near Field Communications (NFC). The proposed solution enables a convenient means for wireless sensing with the operator by simply placing a standard smartphone in close proximity to the cardboard archive box. Wireless sensing capability has the advantage of enabling long-term environmental monitoring of the contents of the archive box without having to move and open the box for reading or battery replacement. This contributes to a sustainable preventive conservation strategy and avoids the risk of exposing the contents to the external environment, which may result in degradation of the stored artifacts. In this work, a low-cost and fully integrated NFC sensor has been successfully developed and demonstrated. The developed sensor is capable of wirelessly measuring temperature and relative humidity with a mean error of 0.37 °C and ±0.35%, respectively. The design has also been optimized for low power operation with a measured peak DC power consumption of 900 μW while yielding a 4.5 cm wireless communication range. The power consumption of the NFC sensor is one of the lowest found in the literature. To the author’s knowledge, the NFC sensor proposed in this paper is the first reporting of a smart archive box that is wirelessly powered and uniquely integrated within a cardboard archive box

A battery-less NFC sensor transponder for museum artefact monitoring - a review of NFC sensor technology and a proposed solution

This paper presents a novel, low-cost, battery-less Near-Field Communication (NFC) sensor transponder for museum artefact monitoring of Cultural Heritage objects. The proposed solution combines a unique combination of packaging materials and NFC technology to enable a low-cost preventive conservation solution that is practical to implement, something that is not possible at present. Cultural Heritage objects and artefacts are valuable objects housed by museums and are often stored in uncontrolled climatic conditions, which may lead to degradation of these objects. Preventive conservation is a new strategy that aims to avoid future degradation of these types of valuable objects. Recently, NFC sensor transponders have shown an increased use in food and pharmaceutical cold supply chains for monitoring, but these commercial solutions are expensive to implement and cannot be easily adapted for museum artefact monitoring. In this work, we present a battery-less, long shelf life, low-cost sensor transponder for monitoring the temperature and humidity conditions inside cardboard artefact storage boxes. In developing the proposed solution, the state of the art NFC sensor technology is first reviewed in detail, and a battery-less NFC sensor transponder is proposed with a cost of less than â ¬5 in quantities of 10k. In addition to this, early-stage prototype results are also presented

A museum artefact monitoring testbed using LoRaWAN

This paper presents a long range wide area network (LoRaWAN) testbed for environmental monitoring of artefacts within a museum storage facility. The goal is to identify the optimum feasible wireless technology for this application by studying eight different wireless technologies. A testbed network was deployed inside a 5600 m 2 concrete building to validate the performance of the candidate wireless technologies by way of measurements. In addition, a LoRaWAN scalability approach was also used to simulate the packet delivery ratio for a 500 node network. The wireless communication performance of LoRa WAN was shown to offer the most optimal solution for wireless communication for museum artefact monitoring application

Low Q^2 Jet Production at HERA and Virtual Photon Structure

The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure

A Search for Selectrons and Squarks at HERA

Data from electron-proton collisions at a center-of-mass energy of 300 GeV are used for a search for selectrons and squarks within the framework of the minimal supersymmetric model. The decays of selectrons and squarks into the lightest supersymmetric particle lead to final states with an electron and hadrons accompanied by large missing energy and transverse momentum. No signal is found and new bounds on the existence of these particles are derived. At 95% confidence level the excluded region extends to 65 GeV for selectron and squark masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure