1,720,961 research outputs found
Measuring thermal conductivity in a microfluidic device with the transient thermal offset (TTO) method
No full textSingle element thermal sensor for measuring thermal conductivity and flow rate inside a microchannel
No full textThe increasing development of continuous-flow applications in the field of microfluidics generates demand for in-line monitoring methods. The thermal conductivity (κ) of a liquid has been proven to be a valuable measurand for quality control, process monitoring, and analytical testing. However, most available methods for measuring κ of microliter-sized samples are limited for use on stagnant samples. In this work, a novel method and associated prototype device for measuring κ under flow conditions is presented. The so-called Transient Thermal Offset (TTO) method requires only a single metal resistive structure that is excitated with direct current (DC) pulses. To demonstrate the working, proof-of-principle experiments are performed on liquids with various κ under different flow rates. The results show that, after calibration, the presented microfluidic device can be used for accurately measuring κ of liquids under flow, as well as for determining the flow rate of liquids with a known κ. Within the explored ranges, both parameters can be determined with an average error of approximately 2.6%. The results confirm that, also under flow conditions, uncertainties concerning probing depth are eliminated with the TTO method.The authors acknowledge the financial support by the DAAD (German Academic Exchange Service) through the project MPFL – Meeting Point Functional Layers
Stretchable printed device for the simultaneous sensing of temperature and strain validated in a mouse wound healing model
Full text linkTemperature and strain are two vital parameters that play a significant role in wound diagnosis and healing. As periodic temperature measurements with a custom thermometer or strain measurements with conventional metallic gauges became less feasible for the modern competent health monitoring, individual temperature and strain measurement modalities incorporated into wearables and patches were developed. The proposed research in the article shows the development of a single sensor solution which can simultaneously measure both the above mentioned parameters. This work integrates a thermoelectric principle based temperature measurement approach into wearables, ensuring flexibility and bendability properties without affecting its thermo-generated voltage. The modified thermoelectric material helped to achieve stretchability of the sensor, thanks to its superior mechano-transduction properties. Moreover, the stretch-induced resistance changes become an additional marker for strain measurements so that both the parameters can be measured with the same sensor. Due to the independent measurement parameters (open circuit voltage and sensor resistance), the sensing model is greatly attractive for measurements without cross-sensitivity. The highly resilient temperature and strain sensor show excellent linearity, repeatability and good sensitivity. Besides, due to the compatibility of the fabrication scheme to low-temperature processing of the flexible materials and to mass volume production, printed fabrication methodologies were adopted to realize the sensor. This promises low-cost production and a disposable nature (single use) of the sensor patch. For the first time, this innovative temperature-strain dual parameter sensor concept has been tested on mice wounds in vivo. The preliminary experiments on mice wounds offer prospects for developing smart, i.e. sensorized, wound dressings for clinical applications
Design of a Lab-on-Chip Cartridge for the Optical Detection of Small Molecules Based on Dye-Displacement MIPs
Full text linkMolecular Imprinted Polymers (MIPs) are well known for their specific recognition of a wide variety of different analytes. However, the complex immobilization process of MIPs onto sensor electrodes poses a significant challenge. This research introduces a novel approach to enhance the application potential of MIPs by exploiting dye-displacement MIPs. These synthetic receptors can selectively release dye upon exposure to an aqueous target. A disposable and low-cost lab-on-chip cartridge is presented, enabling the MIPs to interact with the target solution for dye displacement. Furthermore, these cartridges are coupled to a portable optical sensor setup that can be used for screening samples in a user-friendly and fast manner. Characterization experiments demonstrate the capability of the spectrometer setup to identify different color dyes and intensities. Finally, a proof-of-application shows the use of our sensing setup for the indirect detection of 2-methoxphenidine (2-MXP) using dye-loaded MIPs, employing a dose-response characterization (4PL). Furthermore, as the dye displacement and sensing principle are universal, this setup holds promise for various other sensing applications, including food quality assessment, environmental testing, and pharmaceutical analysis
Liquid Identification in a Microplate Format Based on Thermal and Electrical Sensor Data Fusion
No full textThiswork was supported by AgrEUfood and Food Screening, which is carried out with a contribution from the European Programme Interreg Flanders-Netherlands and Euregio Maas-Rhine
Measuring Thermal Conductivity in a Microfluidic Device With the Transient Thermal Offset (TTO) Method
No full textsponsorship: This work was supported in part by the Research Foundation Flanders FWO within the project G.0791.16.N, in part by BIOMAT project which is carried out under Interreg VAGrensregioVlaanderen-Nederland, in part by theEuropean Union, in part by The European Regional Development Fund, and in part by the province of Limburg-Belgium. This article was presented at the IEEE Sensors 2020 Conference and is published in its Proceedings. The associate editor coordinating the review of this article and approving it for publication was Dr. Sanket Goel. (Research Foundation Flanders FWO|G.0791.16, BIOMAT project, European Union, European Regional Development Fund, province of Limburg-Belgium)status: Publishe
Introducing a Thermal-Based Method for Measuring Dynamic Thin Film Thickness in Real Time as a Tool for Sensing Applications
No full textsponsorship: This work was supported in part by the Research Foundation Flanders FWO under Project G.0791.16.N, in part by the BIOMAT project carried out under Interreg VA Grensregio Vlaanderen-Nederland, and in part by the European Union and The European Regional Development Fund through the Province of Limburg, Belgium. (Research Foundation Flanders FWO|G.0791.16.N, BIOMAT project, European Union, European Regional Development Fund through the Province of Limburg, Belgium)status: Publishe
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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