Detailed Thermal Evaluation of Brazed Plate Heat Exchanger Using Infrared Thermography

Infrared thermography of brazed plate heat exchangers for evaporators and condensers recently was used to quantify maldistribution. With the knowledge of the secondary fluids heat transfer coefficient and a given secondary fluids distribution, the local heat transfer coefficient of the primary fluid (refrigerant) and its distribution to the channels can be calculated. A sensitivity analysis shows ± 10 % difference of the surface temperature to the wall center temperature at the expected ratios of heat transfer coefficients. The method is presented in this paper using an exemplary infrared picture.     

UXO and environmental risk factors impacting EOD operations in German waters**

This article presents risk factors that are associated with the handling of unexploded ordnance (UXO) during explosive ordnance disposal (EOD) operations in German waters. The construction of offshore wind parks and the German immediate action program are expected to increase the number of EOD operations. Existing literature and guidelines do not offer a structured and reproducible framework for assessing EOD risk. To fill this gap, a network of EOD risk factors was developed by means of a literature review and validation via expert consultation. The study was scoped to “personnel and equipment at the EOD location” as the risk receptor and “undesired detonation” as the undesired event under investigation. Factors are subdivided into UXO factors that depend on the object that should be handled and factors that describe the object's surrounding environment. While the former can be researched by an EOD expert, the latter must be measured on site or acquired from a model. Each of these factors contributes to risk, some directly and others indirectly via other factors. The complexity of the resulting network, with its 33 factors, demonstrates the need for a reliable and reproducible model to quantify EOD risk. Its purpose is not to replace EOD experts but to aid them in their decision-making process. Such a tool can provide valuable support for the high-cost and high-risk EOD operations.     

Darstellung und selektive Komplexbildung von Bisorganylsulfiden auf [2.2.2]Paracyclophan‐Basis

The synthesis of a variety of novel functionalized bisorganyl sulfides 2 – 10 based on the [2.2.2]paracyclophane skeleton is described. The aim was to increase the endohedral silver(I) complexation of the unsubstituted [2.2.2]paracyclophane 1 by combining the cyclophane framework with a sulfur containing pendant arm bearing an additional π‐donor. The complexation behaviour of the new ligands was studied by liquid–liquid extraction from aqueous into organic solution. The new ligands reveal a higher extraction with a decreased selectivity for silver(I) compared to 1 caused by preferential interactions with the sulfur donor atoms in the molecule. Molecular modeling calculations show the different coordination patterns for the 1:1‐, 1:2‐ and 2:1‐complexes (M:L) formed in the organic phase.     

Boroleucine-Derived Covalent Inhibitors of the ZIKV Protease

The Zika virus (ZIKV) remains a potential threat to the public health due to the lack of both an approved vaccination or a specific treatment. In this work, a series of peptidic inhibitors of the ZIKV protease with boroleucine as P1 residue was synthesized. The highest affinities with K_i values down to 8 nM were observed for compounds with basic residues in both P2 and P3 position and at the N-terminus. The low potency of reference compounds containing leucine, leucine-amide or isopentylamide as P1 residue suggested a covalent binding mode of the boroleucine-derived inhibitors. This was finally proven by crystal structure determination of the most potent inhibitor from this series in complex with the ZIKV protease.     

Underwater UXO detection using magnetometry on hovering AUVs

The EU-funded project BASTA (Boost Applied munition detection through Smart data inTegration and AI workflows,  http://www.basta-munition.eu ) aimed at improving underwater unexploded ordnance (UXO) detection approaches and advancing data acquisition techniques. One aspect of the project was performing autonomous underwater vehicle (AUV)-based magnetic measurements. In this paper, we present the first results of integrating three submersible fluxgate magnetometers to a Girona 500 AUV in the context of underwater UXO detection. The hovering capabilities of these AUVs allow them to maintain a fixed position or to precisely navigate at very low velocities and altitudes. The magnetic sensors are rigidly attached to the nose of the AUV at a lateral distance of 2 m and are arranged in the shape of a vertical triangle, thereby allowing for the calculation of three spatial magnetic gradients. A series of surveys was performed when visiting several munitions dumpsites in the German Baltic Sea. Furthermore, we successfully conducted a test survey with surrogate objects of known magnetic moments in a naval port basin in Kiel, Germany. With a noise floor of approximately 2 nT, the system is capable of reliably detecting munitions similar in size to 81 mm shells from altitudes of 1 m above the seafloor. For ground-truthing purposes and for a concluding confirmation or rejection of a UXO suspicion, the AUV is equipped with a high-resolution camera system. This newly developed system aims at improving the industry standard's technical potentials of autonomously discriminating between hazardous UXO and anthropogenic debris or rocks and therefore reducing the number of target points before underwater UXO clearance campaigns.