Weldability of micro-alloyed high-strength pipeline steels using a new friction welding variant

An innovative welding method for fully automatic joining of pipelines has been developed. The proposed welding procedure is a variant of the conventional friction welding process. A rotating intermediate ring is used to generate heat necessary to realise the weld. The working principles of the welding process are described. The weldability of the micro-alloyed high-strength pipeline steel API-5L X65 is experimentally investigated. It was found that the new welding process is suitable for joining this material. When welding with a sufficiently low heat input, a high weld quality is obtained. Under these circumstances the weld strength, ductility and impact toughness are high and fulfil the requirements of the commonly used standard EN 12732 for joining pipes

Architectural Model and Modified Long Range Wide Area Network (LoRaWAN) for Boat Traffic Monitoring and Transport Detection Systems in Shallow Waters

Monitoring the movement of boats in shallow waters requires a real-time monitoring system. However, for small-size wooden boats, they are still monitored manually, and data is unavailable in real time, which makes it difficult to effectively monitor them. The integration of IoT platforms with the boat monitoring system is a challenging task, especially in the transport system. This paper has the objective of developing an architectural model of a modified LoRaWAN-based boat monitoring system that is connected to a GPS-based mobile device and base station. The proposed architectural model is an integration of Bluetooth Low Energy (BLE) and LoRaWAN networks, which are also tested in real time to solve the boat traffic monitoring issues. The field tests with parameters of signal transmission, location coordinates, and position of the boats are also presented. The analysis result shows the proposed model is suitable for waters with high noise levels, especially in shallow water and delta rivers. The signal noise can be reduced by extracting the real-time data. In addition, signal interference can be minimized. The performance of this system is also compared to the reference system in real conditions, which shows an adequate correlation result. This proof of concept forms an important basis for deploying it for large-scale applications and commercialization capabilities. Doi: 10.28991/ESJ-2023-07-04-011 Full Text: PD

Selective manipulation of ICT and PeT processes in styryl-Bodipy derivatives : applications in molecular logic and fluoerescence sensing of metal ions

Ankara : The Department of Chemistry and the Institute of Engineering and Sciences of Bilkent University, 2010.Thesis (Master's) -- Bilkent University, 2010.Includes bibliographical refences.Recent developments in the Bodipy chemistry, provided new opportunities for modification of this chromophore which, in turn, using appropriate metal-ligand pairs, allowed the control and manipulation of PeT and ICT mechanisms. Exploiting these mechanisms, we demonstrated that photophysical properties of Bodipy can be shaped as desired using metal cation modulators to obtain absorbance signals in accordance with a digital half-adder circuit. In addition, another Bodipy derivative with a simple and rational design, shown to have emission signals equivalent to AND operation in Boolean logic. A molecular threeinput AND gate was also synthesized taking the advantage of differential binding affinities of metal cations for different ligands. Our work proves that, with careful design, photophysical properties of a single chromophore can be modified as desired. Hence molecular logic gates, and even molecules performing more complex logic operations can be obtained using metal cations as non-annihilating logic inputs.Selçuk, SencerM.S

The isocyano group as a carbenoid function cyclization of ortho-isocyanobiphenyl and derivatives

Cyclization of ortho-isocyanobiphenyl and derivatives with insertion of isocyano carbon to form cycloheptbindole

Current Basic and Pathological Approaches to the Function of Muscle Cells and Tissues

This volume contains 17 short review articles classified into 3 parts. Part I consists of 7 articles dealing with basic aspects of contractile mechanism in skeletal and smooth muscle cells and also function of melanocytes having many properties common to those of smooth muscles. Part II and Part III contain articles dealing with pathological aspects of cardiac and smooth muscle cell functions, and dealing with factors influencing structure and function of cardiac and smooth muscle cells and tissues. The Editor believes that these articles are stimulating and informative for readers interested in basic, pathological and clinical aspects of muscle cells and tissues

Photoactivatable Derivatives for Chemical and Biological Applications: Design, Synthesis and Mechanistic Investigation

This thesis focuses on design, synthesis and mechanistic investigations of photoactivatable derivatives. It summarizes selected results of my Ph.D. research which have been published or submitted for publication. In the theoretical part it summarizes basic information about selected topics relevant for the studied projects, such as photoremovable protecting groups, selected visible light absorbing chromophores, biologically relevant caged ions and small molecules, and visible light photocatalysis. The part Results and Discussion is divided into eight chapters. The first chapter deals with a xanthene-based photoremovable protecting group (PPG). We managed to prepare the first PPG capable to release phosphates, carboxylates and halides by the action of green light (λmax ~ 520 nm). The second part introduces 4-hydroxyphenacyl fluoride, a caged fluoride, that can be efficiently released (Φ ~ 84%) by UV-light irradiation. The mechanism of fluoride release has been studied by picosecond pump-probe spectroscopy. The released fluoride was used for etching of silicon surfaces followed by AFM. The third project describes the first metal-free carbon monoxide-releasing molecule (CORM) activatable by visible light based on the xanthene structural motif. The fourth chapter improves the concept of visible light absorbing CORMs by using BODIPY-based chromophores. These molecules can release CO upon irradiation by light at up to 730 nm and were successfully tested in both in vitro and in vivo biological experiments. The mechanism of the photodegradation was carefully studied. The fifth chapter deals with a photocatalytic system for reduction of carbonyl compounds. It uses proflavine as a photocatalyst, rhodium mediator, and triethylamine as a sacrificial electron donor. The system selectively reduces aldehydes over ketones. Both electronic and steric effects are responsible for the selectivity which is kinetically controlled. The sixth project describes a novel photocatalytic method for generation of the nitrate radical which is further used for some synthetic applications. The mechanism of generation of the nitrate radical by photooxidation of the nitrate anion has been studied in detail. The seventh chapter discusses a new method for generation of fluorinated aryl radicals which are used in the synthesis of fluorinated biaryls as well as in late stage functionalization of some complex molecules. The transient spectroscopic study has revealed the mechanism of the aryl radical formation. The last project focuses on the synthesis of selanyl- and tellanyl-substituted BODIPY derivatives. The quantum yield of intersystem crossing (up to 60%) has been measured by transient spectroscopy. These derivatives can be used as triplet sensitizers

Polyconductivity in polypyrrole: The correlated electron glass

p-toluensulfonate doped polypyrrole ~PPy!, undergoes an electric-field induced reversible transition from an insulating state to a highly conductive one. The spatially average field can be as small as 200 V/cm, when the temperature of the sample is below 20 K. The applied electric field leads to a sharp jump in the value of the current to a value which is nearly five orders of magnitude higher than before. When the applied electric field is reduced to below a critical value, the system switches back to a low conductive state. The effect is reversible, symmetric in voltage, and reproducible for different samples. The switching is, we believe, an electronic glass melting transition and it is due to the disordered, highly charged granular nature of PPy