Academic literature on the topic 'Dip-NMR system'

Abstract. We introduce a low-complexity, low-cost, yet sufficiently accurate automatic tune and match system for NMR and MRI applications. The ArduiTaM builds upon an Arduino Uno embedded system that drives a commercial frequency synthesiser chip to perform a frequency sweep around the Larmor frequency. The generated low-power signal is fed to the NMR coil, after which the reflected waves are detected using a directional coupler and amplified. The signal shape is then extracted by means of an envelope detector and passed on to the Arduino, which performs a dip search while continuously generating actuator control patterns to adjust the tune and match capacitors. The process stops once the signal dip reaches the Larmor frequency. The ArduiTaM works readily with any spectrometer frequency in the range from 1 to 23 T. The speed of the ArduiTaM is mainly limited by the clock of the Arduino and the capacitor actuation mechanism. The Arduino can easily be replaced by a higher-speed microcontroller, and varactors can replace stepper-motor controlled variable capacitors. The ArduiTaM is made available in open source, and so is easily duplicated.

Acetylide and thiourea moieties individually provides a wide range of electronic properties as they possess electronic delocalization in extended rigid π orbital system in their designated structures. In this work, a new derivative of N-([4–aminophenyl] ethynyltoluene)-N’-(1-naphthanoyl) thiourea (ATT) was successfully synthesized and spectroscopically characterized by using FT-IR, NMR, and UV-Vis analysis. In turn, the development of new sensing material thin-film based on ATT has been accomplished by incorporating with polyvinyl chloride (PVC) via dip-coating technique. The difference in absorption behavior using UV-visible spectroscopic analysis was employed to determine the sensitivity of thin-film towards carbon monoxide (CO) gas of 10, 20, and 30 ppm. ATT exhibits high sensitivity towards 30 ppm CO gas with 55% sensitivity. Quantum mechanical calculation via Gaussian 09 shows that ATT has potential van der Waals interaction towards CO with stabilization energy-6.54 kJ/mol and 3.14Ǻ of interaction distance between substrate and analyte. It is proven that ATT as single molecule gives great potential to be explored and used as sensing material application particularly in CO detection.

ABSTRACTSuperconducting films in the Bi-Sr-Ca-Cu-O system were fabricated using metal alkoxides. To make a mixed alkoxide solution into a dip-coating solution, insoluble Cu alkoxide was modified with 2-dimethylaminoethanol and insoluble Bi alkoxide was dissolved in the presence of Ca and/or Sr alkoxides. The structures of these alkoxide derivatives were studied by FT-IR, 1 H-NMR, and EXAFS. The film with Tc(zero)=115K was fabricated using the alkoxide solution with a nominal composition of Bi:Sr:Ca:Cu=2:2:3:4.

The investigation of reaction mechanisms is a complex task that usually requires the use of several techniques. To obtain as much information as possible on the reaction and any intermediates ‐ possibly invisible to one technique ‐ the combination of techniques is a solution. In this work we present a new setup for combined UV/Vis and NMR spectroscopy and compare it to an established alternative. The presented approach allows a versatile usage of different commercially‐available components like mirrors and fiber bundles as well as different fixed pathlengths according to double transmission or single transmission measurements. While a previous approach is based on a dip‐probe setup for conventional NMR probes, the new one is based on a micro‐Helmholtz coil array (LiquidVoxel™). This makes the use of rectangular cuvettes possible, which ensure well‐defined pathlengths allowing for quantification of species. Additionally, very low quantities of compound can be analyzed due to the microfabrication and small cuvette size used. As proof‐of‐principle this new setup for combined UV/Vis and NMR spectroscopy is used to examine a well‐studied photochromic system of the dithienylethene compound class. A thorough comparison of the pros and cons of the two setups for combined UV/Vis and NMR measurements is performed.

Dans ce travail de thèse nous présentons notre contribution à la mise au point d’un spectromètre RMN immersible miniature à bas-cout (DIP-NMR) permettant de suivre des réactions chimiques directement sous la hotte ou dans les réacteurs industriels. Nous avons pu tester et optimiser la première version d’un prototype enregistrant des spectres à un scan de produit pur, beaucoup de travail reste à faire pour développer une sonde immersible pouvant faire des acquisitions sur plusieurs canaux simultanément.Les premiers spectres obtenus sur notre prototype sont larges et nous avons dû tester et mettre au point des méthodes chimio-métriques pour extraire les données cinétiques et quantitatives. Ces méthodes ont pu être testés sur des données obtenues sur des spectromètres haut champs volontairement dégradés.En parallèle, une série de réactions d’hydrosilylation de substrats organiques (Nitriles, Esters, Amides Cyclique) en présence d’un catalyseur à base d’Ir(III) ont été suivies par RMN à haut champ et haute résolution. Ce travail a permis de mieux comprendre les mécanismes mis en jeu et d’obtenir des données cinétiques de référence pour les tests des prochaines versions de nos spectromètres immersibles
This endeavour represents a pioneering effort to design and develop a cost-effective low-field Dip-NMR or Immersible NMR system dedicated to monitoring reaction mixtures at the closest possible source of information. While we have successfully designed and optimized the first version of prototype capable of acquiring single scanned NMR spectra of pure samples, further focused study and research are highly warranted to develop and integrate prototype into an immersible probe unit capable of multi-channel acquisition to realize the proposed Dip-NMR system. The NMR spectra obtained from Dip-NMR system were notably broad and necessitated dedicated chemometric methods for quantification and kinetic data extraction. Known reactions were monitored on a high-field high-resolution NMR spectrometer, with the kinetic data from this instrument serving as benchmark data for comparison and evaluation against the data obtained from Dip-NMR system. Various chemometric methods were explored and tested on the mimicked spectra for quantification and kinetic data extraction, with the results subsequently compared with the benchmark data. In parallel with the project’s goal, hydrosilylation reactions involving organic substrates such as nitriles, cyclic amides, and esters were catalyzed using an Ir(III) catalyst and monitored on a high-field high-resolution NMR spectrometer. These investigations have successfully yielded valuable insights into the reactions, contributing to a deeper understanding of the processes involved and laid important reference kinetic data for future testing of an advanced Dip-NMR probe prototype

Abstract This case study well is in a mature onshore field, which has been under production for a long time (started in 1970) resulting in depletion of some of the reservoir units presenting challenges for optimizing drilling performance and managing risks associated with stuck-pipe incidents. Additional challenges are minimized surface footprint, 100% reservoir contact in thin targets and acquisition of accurate petrophysical data for formation evaluation. A detailed pre-well study was conducted utilizing historical field and nearby wells’ data in the planning phase with close collaboration in a multi-disciplinary team including well and Bottom Hole Assembly (BHA) design and pre-well modeling for geosteering and LWD tool string configuration taking into account the elimination of radioactive chemical sources. The pre-well study has concluded that the azimuthal deep propagation resistivity image is going to provide proactive geosteering solution to identify the approach to both top and bottom boundaries. The BHA has also included rotary steerable system (RSS) along with optimized Logging While Drilling technologies (LWD) which has included, high-resolution micro resistivity imaging, Laterolog resistivity, nuclear magnetic resonance (NMR), sonic caliper and near-bit gamma ray. Continuous real-time monitoring provided drilling performance monitoring and analysis as well as facilitating geosteering services. The 8,356 feet horizontal section was effectively geosteered with 100% reservoir contact tapping into two thin reservoir sub-layers. Real-time azimuthal deep propagation resistivity image/curves were used to geosteer the well trajectory precisely within target zones and provided 4-5 feet TVD detection to bed boundaries. Also, high-resolution microresistivity images, dip picks and near-bit azimuthal gamma ray helped in maintaining the well-bore attitude parallel to the stratigraphy within each sub-layer. This data facilitated a smooth transition from one sub-layer to the next with minimum borehole tortuosity aided by the push the-bit RSS and at-bit-inclination measurements. In addition, NMR provided real-time porosity and permeability measurements assisting in well placement and enhancing reservoir understanding as well as optimizing future well planning workflows. This paper presents a step change from the traditional field development drilling techniques in terms of horizontal length. Similar well designs are currently being implemented in an effort to benchmark drilling, well placement and petrophysical data gathering requirements for future development drilling in order to maximize asset value.