TY  - JOUR
A1  - Ayala, Rafael Ceja
A1  - Harris, Isaac
A1  - Kleefeld, Andreas
T1  - Direct sampling method via Landweber iteration for an absorbing scatterer with a conductive boundary
JF  - Inverse Problems and Imaging
N2  - In this paper, we consider the inverse shape problem of recovering isotropic scatterers with a conductive boundary condition. Here, we assume that the measured far-field data is known at a fixed wave number. Motivated by recent work, we study a new direct sampling indicator based on the Landweber iteration and the factorization method. Therefore, we prove the connection between these reconstruction methods. The method studied here falls under the category of qualitative reconstruction methods where an imaging function is used to recover the absorbing scatterer. We prove stability of our new imaging function as well as derive a discrepancy principle for recovering the regularization parameter. The theoretical results are verified with numerical examples to show how the reconstruction performs by the new Landweber direct sampling method.
Y1  - 2024
U6  - https://doi.org/10.3934/ipi.2023051
SN  - 1930-8337
SN  - 1930-8345 (eISSN)
VL  - 18
IS  - 3
SP  - 708
EP  - 729
PB  - AIMS
CY  - Springfield
ER  - 
TY  - JOUR
A1  - Aliazizi, Fereshteh
A1  - Özsoylu, Dua
A1  - Bakhshi Sichani, Soroush
A1  - Khorshid, Mehran
A1  - Glorieux, Christ
A1  - Robbens, Johan
A1  - Schöning, Michael Josef
A1  - Wagner, Patrick
T1  - Development and Calibration of a Microfluidic, Chip-Based Sensor System for Monitoring the Physical Properties of Water Samples in Aquacultures
JF  - Micromachines
N2  - In this work, we present a compact, bifunctional chip-based sensor setup that measures the temperature and electrical conductivity of water samples, including specimens from rivers and channels, aquaculture, and the Atlantic Ocean. For conductivity measurements, we utilize the impedance amplitude recorded via interdigitated electrode structures at a single triggering frequency. The results are well in line with data obtained using a calibrated reference instrument. The new setup holds for conductivity values spanning almost two orders of magnitude (river versus ocean water) without the need for equivalent circuit modelling. Temperature measurements were performed in four-point geometry with an on-chip platinum RTD (resistance temperature detector) in the temperature range between 2 °C and 40 °C, showing no hysteresis effects between warming and cooling cycles. Although the meander was not shielded against the liquid, the temperature calibration provided equivalent results to low conductive Milli-Q and highly conductive ocean water. The sensor is therefore suitable for inline and online monitoring purposes in recirculating aquaculture systems.
KW  - chip-based sensor setup
KW  - aquaculture
KW  - microfluidics
KW  - impedance spectroscopy
KW  - thermometry
KW  - electrical conductivity of liquids
Y1  - 2024
U6  - https://doi.org/10.3390/mi15060755
SN  - 2072-666X
N1  - This article belongs to the Special Issue "Multisensor Arrays"
N1  - Corresponding author: Michael J. Schöning
VL  - 15
IS  - 6
PB  - MDPI
CY  - Basel
ER  -