Magnetic Resonance Spectrometer Research Articles

Crude Oil -Water Emulsions Formed by Nozzle Type Inflow Control Device

Conventional water-in-oil emulsion studies where shear energy intensity and duration are applied to achieve ‘equilibrium’ emulsion droplet properties may not represent partial emulsion conditions observed in single pass flow through Inflow Control Device (ICD) orifices. Our experiments provide data expected to improve emulsion transport models for partial emulsification processes expected in well completion and production tubulars. Development of a novel flow adaptor apparatus is described together with a laboratory homogeniser enables independent control of shear intensity and duration together with input water volume fraction. The emulsions formed are characterised with a benchtop Nuclear Magnetic Resonance spectrometer for water content and droplet size, viscosity by a rotating bob viscometer and free water / emulsion proportion by optical photography. Experimental results confirmed partial emulsification above 30% V/V, as observed in both previous ICD flow experiments and field observations. Electrical conductivity measurements of the emulsions produced indicated that partial emulsification comprising an oil external emulsion phase together with free water rather than emulsion inversion occurs in this system.

Study on the Effect of Sorghum Flour Particle Size on the Storage Quality of Leavened Pancakes.

Pancakes prepared with sorghum flour possess a high nutritional value, yet their quality is unstable and prone to degradation during storage. This instability can be attributed to the particle size of coarse cereal powder, which significantly influences the quality of flour products during storage. In this study, changes in the quality of these pancakes, prepared with varying particle sizes of sorghum flour, were meticulously analyzed during cold storage using advanced instruments such as a texture analyzer, nuclear magnetic resonance spectrometer, differential scanning calorimeter, X-ray diffractometer, and Fourier transform infrared spectrometer. Findings revealed that the hardness of leavened pancakes significantly increased over time. After a refrigeration period of 7 days, the hardness of wheat flour leavened pancakes increased by 56.60%. However, with a decrease in the particle size of sorghum flour, the increase in hardness diminished, thereby delaying the aging process of the pancakes. As the storage duration was extended, moisture migration within the pancakes occurred, and the sorghum flour pancakes with a smaller particle size exhibited a reduced moisture change rate, indicating an enhanced water holding capacity. In comparison to their wheat flour counterparts, sorghum flour leavened pancakes exhibited a substantial reduction in retrogradation enthalpy and crystallinity. The inclusion of sorghum flour effectively inhibited amylopectin recrystallization, thus slowing down the aging process of the pancakes. This inhibitory effect was more evident with decreasing sorghum flour particle sizes. Fourier transform infrared data indicated no significant alterations in absorption peaks across various wavelengths during cold storage. Although starch short-range orderliness increased with storage time, the use of sorghum flour with smaller particles reduced the degree of short-range orderliness in starch molecules throughout the cold storage period. Sorghum flour with a smaller particle size can inhibit water migration and amylopectin recrystallization, which subsequently delays pancake aging and enhances its quality stability during storage.

Effect of Dicarboxylic Acid Chain Length on the Tribological Properties of Aqueous Polyether Esters

ABSTRACTThis article presents the preparation of environmentally friendly water‐soluble lubricant additives. Adipic acid (AA), sebacic acid (SA) and dodecanedioic acid (DA) were individually subjected to esterification reactions with polyethylene glycol 1500 (PEG1500) to prepare a class of water‐soluble polyether esters (AAPEE1500, SAPEE1500 and DAPEE1500) (referred to as XAPEE1500s) that exhibit excellent water solubility and do not contain environmentally harmful elements. First, the molecular structure characterisation and functional group analysis of these additives will be conducted using an infrared spectrometer and a nuclear magnetic resonance spectrometer. Subsequently, the frictional properties of the additives in the base liquid (deionised water) will be investigated using an SRV‐V tribometer, Falex pin‐on‐disc tribometer and screw torque tester. The surface morphology of wear scars will be characterised and analysed using scanning electron microscopy (SEM) and a non‐contact 3D profilometer. Finally, the lubrication mechanism of the DAPEE1500 additive will be analysed using X‐ray photoelectron spectroscopy (XPS). The results indicate that the optimal lubrication performance is achieved when the added mass fraction of DAPEE1500 is at 3%. Compared with 0.5 wt% DAPEE1500, the average friction coefficient of 3 wt% DAPEE1500 decreased from 0.285 to 0.122, and the wear volume decreased from 25.52 × 10−5 μm3 to 10.96 × 10−5 μm3. The lubrication mechanism of polyether ester is the result of the combined action of its polar ester functional groups and long carboxylic acid chains in the structure. These polar functional groups can form a relatively firm adsorption film on the friction surface, while the long carboxylic acid chains act as a brush‐like isolating layer, thus demonstrating superior anti‐wear and anti‐friction performance.

Benchtop NMR Coupled with Chemometrics: A Workflow for Unveiling Hidden Drug Ingredients in Honey-Based Supplements.

Recently, benchtop nuclear magnetic resonance (NMR) spectrometers utilizing permanent magnets have emerged as versatile tools with applications across various fields, including food and pharmaceuticals. Their efficacy is further enhanced when coupled with chemometric methods. This study presents an innovative approach to leveraging a compact benchtop NMR spectrometer coupled with chemometrics for screening honey-based food supplements adulterated with active pharmaceutical ingredients. Initially, fifty samples seized by French customs were analyzed using a 60 MHz benchtop spectrometer. The investigation unveiled the presence of tadalafil in 37 samples, sildenafil in 5 samples, and a combination of flibanserin with tadalafil in 1 sample. After conducting comprehensive qualitative and quantitative characterization of the samples, we propose a chemometric workflow to provide an efficient screening of honey samples using the NMR dataset. This pipeline, utilizing partial least squares discriminant analysis (PLS-DA) models, enables the classification of samples as either adulterated or non-adulterated, as well as the identification of the presence of tadalafil or sildenafil. Additionally, PLS regression models are employed to predict the quantitative content of these adulterants. Through blind analysis, this workflow allows for the detection and quantification of adulterants in these honey supplements.

Efficient extraction of Au(Ⅲ) by a piperidine-based ionic liquid and exploration of the mechanism driving force

Efficient gold extraction is of paramount importance, but how to improve the extraction efficiency and enhance the driving force of the extraction process is still to be explored. This study introduces an innovative approach using versatility ionic liquids (ILs) to overcome existing challenges. A tailored IL was synthesized and employed computational tools, including the Interaction Region Indicator, to predict its effectiveness in gold extraction. Quantum chemical calculations elucidated the interplay between hydrogen bonding capability and ion exchange properties of the ILs. Subsequent optimization of experimental conditions (0.1 mol/L HCl, 10.6 mg IL) yielded a remarkable 98.4 % extraction efficiency at 45 °C. Molecular dynamics simulations affirmed the IL's exceptional selectivity for Au(III) extraction, with analysis revealing that the extraction mechanism primarily hinged on electrostatic attraction and van der Waals interactions between ionic liquid cations and [AuCl4]−. This mechanism aligns with the established anion exchange mechanism, validated through Ultraviolet–visible spectrometer (UV–Vis), Nuclear Magnetic Resonance spectrometer (NMR), and Liquid Chromatograph Mass Spectrometer (LC-MS) analyzes. To complete the extraction cycle, 1.0 mol/L K2C2O4 was employed as a stripping agent for efficient Au(III) recovery from the loaded IL phase, facilitating repeated extraction cycles. This study underscores the sustainability of the IL-based Au(III) extraction process, maintaining consistently high extraction rates even after five cycles. In summary, this method does not use solvent, enabling environmentally friendly Au(III) extraction.

Chloride ion permeability of concrete containing recycled composite powder from building demolition waste

Buildings in the marine environment are vulnerable to chloride ion erosion, which threatens the service life of concrete structures. To facilitate the application of concrete containing construction demolition waste in the marine environment, recycled composite powder concrete (RCPC) was prepared using recycled composite powder as cement substitute. The chloride ion permeability of RCPC was evaluated by chloride ion diffusion test and rapid chloride ion migration test (RCM). The chloride ion permeability of RCPC continued to enhance with growing content of recycled composite powder. During the immersion age, the surface chloride ion content of the samples containing recycled composite powder increased by an average of 18.3–65.3% over the control group, with a corresponding average increase in chloride ion diffusion coefficients ranging from 17.0% to 31.5%. The chloride ion migration coefficients in the RCM test raised by 9.5–24.7%. A series of microscopic tests such as nuclear magnetic resonance (NMR), X-ray diffraction (XRD) and scanning electron microscope-energy dispersive spectrometer (SEM-EDS) suggested that the total porosity increased by 11.9–29.5% with the addition of recycled composite powder. The chloride ion diffusion coefficients exhibited a linear increase with growing total porosity and porosity of capillary pores, whereas an exponential increase with the porosity of transitional pores. The poor reactivity of the recycled composite powder resulted in a looser microstructure and weakened chloride binding capacity, and these factors boosted chloride ion transport. A chloride ion diffusion model of RCPC considering the time dependence of chloride ion transport was developed, and the reliability of the model was verified by experimental data.

Removal of rubidium from brine by an integrated film of sulfonated polysulfone/graphene/potassium copper ferricyanide

A novel integrated film of sulfonated polysulfone/graphene/potassium copper ferricyanide (KCuFC/SPSG) was used for selectively extracting rubidium ion (Rb+) from brine. To form KCuFC/SPSG, the precursor film of sulfonated polysulfone/graphene (SPSG) was synthesized by phase conversion process, which was alternately immersed in 0.1 mol·L–1 CuSO4/K4[Fe(CN)6] by in-situ adsorption coupled co-precipitation method. Various data such as nuclear magnetic resonance spectrometer, Fourier transform infrared spectroscope, X-ray photoelectron spectroscope, X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy all verified that abundant KCuFC were uniformly located on the film. The resulting KCuFC/SPSG was used in film separation system. As the solution was fed into the system, the Rb+ could be selectively adsorption by KCuFC/SPSG. After the saturation adsorption, 0.5 mol·L–1 NH4Cl/HCl was fed into the film cell, Rb+ could be quickly desorbed by ion-exchange between Rb+ and NH4+ in the lattice of KCuFC. The purpose of separating and recovering Rb+ from the brine can be achieved after the repeated operation. The effects of pH, adsorption time and interferential ions on the adsorption capacity of Rb+ were investigated by batch experiments. The adsorption behavior fits the pseudo-second order kinetic process, while KCuFC has a higher adsorption capacity (Langmuir maximum sorption 165.4 mg∙g–1). In addition, KCuFC/SPSG shows excellent selectivity for Rb+ even in complex brine systems. KCuFC/SPSG could maintain 93.5% extraction efficiency after five adsorption/desorption cycles.

Analysis of complex mixtures with benchtop nuclear magnetic resonance: Solvent suppression with T2 and diffusion filters.

Benchtop nuclear magnetic resonance (NMR) spectrometers are being employed in a wide variety of applications from undergraduate teaching and research in academia to quality control and process monitoring in industrial settings. Incorporating benchtop NMR in some of these applications presents opportunities for new practical uses of the technology and challenges that truly test the capabilities of compact NMR spectrometers. For instance, the use of protonated solvents in manufacturing or process monitoring requires separating and quantitating the analyte signals of interest from the strong (overwhelming) response from the solvents. Furthermore, due to the lower field strength available with permanent magnet spectrometers, the NMR spectra of complex mixtures can be more difficult to analyze due to partial or complete signal overlap. To address some of these challenges and to extend the range of applications of benchtop NMR, we investigate NMR techniques that enable quantitative analysis of different components in mixtures. These pulse sequences can be used to suppress one or multiple solvent peaks, to filter out signals by spin-spin relaxation time (T2), or to separate signal components by a molecule's diffusion coefficient (NMR diffusometry). In this paper, we discuss quantitative analysis of excipients in buffers for therapeutic proteins to highlight the usefulness of these NMR pulse sequences in the analysis of complex samples with benchtop NMR spectrometers.

Cryogen-free 400-MHz nuclear magnetic resonance spectrometer as a versatile tool for pharmaceutical process analytical technology.

The discovery of new ceramic materials containing Ba-La-Cu oxides in 1986 that exhibited superconducting properties at high temperatures in the range of 35 K or higher, recognized with the Nobel Prize in Physics in 1987, opened a new world of opportunities for nuclear magnetic resonance (NMRs) and magnetic resonance imaging (MRIs) to move away from liquid cryogens. This discovery expands the application of high temperature superconducting (HTS) materials to fields beyond the chemical and medical industries, including electrical power grids, energy, and aerospace. The prototype 400-MHz cryofree HTS NMR spectrometer installed at Amgen's chemistry laboratory has been vital for a variety of applications such as structure analysis, reaction monitoring, and CASE-3D studies with RDCs. The spectrometer has been integrated with Amgen's chemistry and analytical workflows, providing pipeline project support in tandem with other Kinetic Analysis Platform technologies. The 400-MHz cryofree HTS NMR spectrometer, as the name implies, does not require liquid cryogens refills and has smaller footprint that facilitates installation into a chemistry laboratory fume hood, sharing the hood with a process chemistry reactor. Our evaluation of its performance for structural analysis with CASE-3D protocol and for reaction monitoring of Amgen's pipeline chemistry was successful. We envision that the HTS magnets would become part of the standard NMR and MRI spectrometers in the future. We believe that while the technology is being developed, there is room for all magnet options, including HTS, low temperature superconducting (LTS) magnets, and low field benchtop NMRs with permanent magnets, where utilization will be dependent on application type and costs.

MaDDOSY (Mass Determination Diffusion Ordered Spectroscopy) using an 80MHz Bench Top NMR for the Rapid Determination of Polymer and Macromolecular Molecular Weight.

Measurement of molecular weight is an integral part of macromolecular and polymer characterization which usually has limitations. Herein, this article presents the use of a bench-top 80MHz Nuclear Magnetic Resonance (NMR) spectrometer for diffusion-ordered spectroscopy as a practical and rapid approach for the determination of molecular weight/size using a novel solvent and polymer-independent universal calibration.

Automated self-optimization, intensification, and scale-up of photocatalysis in flow.

The optimization, intensification, and scale-up of photochemical processes constitute a particular challenge in a manufacturing environment geared primarily toward thermal chemistry. In this work, we present a versatile flow-based robotic platform to address these challenges through the integration of readily available hardware and custom software. Our open-source platform combines a liquid handler, syringe pumps, a tunable continuous-flow photoreactor, inexpensive Internet of Things devices, and an in-line benchtop nuclear magnetic resonance spectrometer to enable automated, data-rich optimization with a closed-loop Bayesian optimization strategy. A user-friendly graphical interface allows chemists without programming or machine learning expertise to easily monitor, analyze, and improve photocatalytic reactions with respect to both continuous and discrete variables. The system's effectiveness was demonstrated by increasing overall reaction yields and improving space-time yields compared with those of previously reported processes.

Investigation of Nearest Neighbor Interactions in Nickel Substituted Cobalt Using 59Co IFNMR

Co100-x Nix (x = 10, 20, 30, 40) alloys were synthesized via the chemical method by reducing nitrates of cobalt and nickel using hydrazine as a reducing agent. The proportion of solvents, ethanol, and water was maintained constant for all the samples in the series. The structure and morphology of the samples were examined based on X-Ray diffraction (XRD) data and Scanning Electron Microscope (SEM) images. From XRD it was evident that the system had a mixture of hexagonal close packed (hcp) and face centered cubic (fcc) phases. The amount of hcp phase in the composition gradually reduced as the concentration of nickel increased. The effect of substitution of nickel on cobalt was studied using a home built 59Co internal field nuclear magnetic resonance (IFNMR) spectrometer. Further, the saturation magnetization and hence magnetic field anisotropy values, obtained from M vs H loops, are found to vary with nickel concentration. The NMR results show a broadening of the NMR signals in comparison with the pure phase of cobalt. The NMR spectra and the number of peaks were assigned to possible cobalt-nickel neighbors, and the percentage of such combinations is interpreted in terms of the frequency and intensity of the peaks. This percentage of different nickel-cobalt combinations was compared with the random distribution obtained using the binomial distribution function. This comparison shows a clear trend compared to that analysed by the IFNMR experiment.

Antibacterial activity of five Indonesian medicinal plants and the isolation of compounds from Plectranthus scutellarioides

The purpose of this study is to investigate the antibacterial properties of five Indonesian medicinal plant extracts, namely Physalis angulata, Loranthus parasiticus, Plectranthus scutellarioides, Cyperus rotundus, and Terminalia catappa. The isolation of compounds from P. scutellarioides against pathogenic bacteria was also investigated. The assessment of the antibacterial activity of the extracts was conducted using the microdilution-3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide method against Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). The plant extract with the highest antibacterial activity was further purified using various chromatographic assays to isolate bioactive compounds. High Resolution-Electron Ionization Mass Spectroscopy/Electrospray Ionization Mass Spectroscopy (HR-ESIMS/EIMS) and Nuclear Magnetic Resonance (NMR) spectrometers were used to elucidate the structure of isolated compounds. Among all the plants tested, P. scutellarioides showed the strongest antibacterial activity against S. aureus [minimum inhibitory concentration (MIC 100 μg/ml)] and B. subtilis (MIC 200 μg/ml). Three compounds were isolated from P. scutellarioides including an abietane diterpene, 2,16-diacetoxy-6,11,12,14,17-pentahydroxy-abieta-5,8,11,13- tetraene-7-one (1), 5,6,7,3′,4′,5′-hexamethoxy flavone (2), and 5,6,7,8,3′,4′,5′-heptamethoxy flavone (3). Compounds 2 and 3 were recognized to be first isolated from this plant. Compound 1 exerted antibacterial activity against S. aureus with a MIC value of 60 μM, but was inactive against B. subtilis and E. coli (MIC > 200 μM). Compounds 2 and 3 were inactive against S. aureus, B. subtilis, and E. coli (MIC > 200 μM).

Spectroscopic Characterization And Antimicrobial Studies Of Synthesized N-Benzyl-1h-Indole-3-Carboxamide

A four step synthetic approach afforded N-benzyl-1H-indole-3-carboxamide in a moderate yield. The process involved formylation with Vismeier-Haack reagents, followed by disproportionation through the Cannizzaro reaction, chlorination using thionyl chloride, and subsequent substitution with benzylamine, ultimately generating the target compound. The compound was analysed using, 1H NMR (Proton nuclear magnetic resonance), 13C NMR (carbon nuclear magnetic resonance) and FTIR (fourier transform infrared) spectrophotometry. The FT-IR spectrum of the compound show characteristics peaks at 1540 cm-1 for C=C of benzene ring, at 1660 cm-1 for C=O of amide, sp3 C-H stretching frequency, that is, the methylene bonded to the nitrogen of the amide at 2900 cm-1, N-H. The proton and carbon data were obtained using the aforementioned nuclear magnetic resonance spectrometers, and the corresponding spectrum displaced chemical shifts that align with the proposed structure of the target molecule.

Study of 1-Formyl-2-Pyrazolines as Anticancer Drug Candidates

The development of novel anticancer agents is essential in cancer prevention. One versatile group of compounds, known for their significant bioactivity and several of its derivatives that have been clinically approved, is the group of pyrazolines. This study aimed to synthesize 1-formyl-2-pyrazoline derivatives (pyrazolines 1-2) using chalcone 1-2, hydrazine hydrate, and formic acid via cyclo-condensation. The synthesized compounds were characterized using Fourier Transform Infrared (FTIR), Gas Chromatography-Mass Spectrometry (GC-MS), and Nuclear Magnetic Resonance (1H- and 13C-NMR) spectrometers. Pyrazolines 1-2 were found to be drug-like compounds, satisfying Lipinski’s Rule of Five and possessing favourable absorption, distribution, metabolism, and excretion (ADME) properties, including good gastrointestinal absorption, blood-brain barrier permeability, and no interaction with P-glycoprotein. Furthermore, they were inactive against several toxicity endpoints in a normal body condition, such as immunotoxicity, mutagenicity, and cytotoxicity. In vitro cytotoxic evaluation of the pyrazolines 1-2 against HeLa and MCF7 cancer cell lines demonstrated moderate activity, with IC50 values of 25.01 µM and 82.87 µM, respectively. Pyrazolines 1-2 also showed good selectivity with selectivity index (SI) values of 8.92 and 14.45. The molecular docking study on epidermal growth factor receptor tyrosine kinase (EGFR-TK) (PDB ID: 4HJO) revealed that pyrazolines 1-2 had a binding affinity of -7.9 and -8.0 kcal/mol, respectively. The compounds interacted with Lys721 residue through hydrogen bonds and hydrophobic interactions due to the presence of the pyrazoline ring and the formyl group in their structures. These findings suggest that pyrazolines 1-2 scaffold has the potential to be further studied as a lead compound for anticancer drug candidates.

Molecular and qualitative characterization of compatibility between valacyclovir hydrochloride and excipients as raw materials for the development of solid oral dosage formulation

Objectives: The objective of this present study is to know the compatibility of valacyclovir hydrochloride (VCH) with common excipients that would be utilized to develop solid oral dosage forms. Several spectroscopy techniques were used to know the possible interactions of VCH with excipients. More, a molecular docking study was also carried out to see the interaction of VCH with excipients. In vitro study of a physical mixture of VCH with excipients was executed to know the release of a drug. Material and Methods: Several analytical techniques such as differential scanning calorimetry, nuclear magnetic resonance spectrometer, and Fourier-transform infrared (FTIR) spectroscopy have been utilized to know the drug-excipient compatibility. Further, possible interactions between valacyclovir and different excipients were assessed by thin-layer chromatography. In vitro dissolution studies in different sets of experiments were done to determine the influence of the hydrophobic and hydrophilic nature of excipients (on the dissolution profile of VCH using USP II-type dissolving apparatus). Moreover, in silico molecular docking studies were also done to know any possible molecular interactions among drugs and excipients using AutoDock VINA 1.2.0 software and GROMACS 5.0 software. Results: FTIR and 1H NMR spectra of VCH and physical mixtures of VCH and excipients were compared and it was observed that no significant deviation of characteristic peaks in infrared spectroscopy and 1H NMR signals was detected. The endothermic peak of VCH in the physical mixtures of drugs and excipients was found in approximately the same position. In vitro dissolution studies displayed the influence of the hydrophobic and hydrophilic nature of excipients on the dissolution profile of VCH. For the physical mixture of VCH with lactose (LAC) and dicalcium phosphate (DP), % drug release was found to be 31.96% and 33.16% at 10 min, whereas the amount of % drug released for the mixture of VCH and talc was 25.00%. For two other excipients such as LAC and DP, the % drug release was determined to be 42.96% and 41.64%, respectively, for 30 min. The docking study also provided insights into the lowest energy conformations. Docking study anticipated that the number of interactions were more between valacyclovir and LAC (four nos.) in comparison to valacyclovir and microcrystalline cellulose (MCC) (two nos.). This interaction showed that in vitro drug release for the physical mixture of VCH with MCC was higher than a mixture of valacyclovir with LAC. Conclusion: A compatibility study of VCH by analytical techniques established that VCH was compatible with utilized excipients. Drug dissolution of VCH and physical mixture of MCC exhibited the maximum amount of drug release whereas a mixture of VCH with magnesium stearate released the minimum amount of drug for both short (10 min.) and long (30 min.) period. Docking studies disclosed that the LAC complex showed less deviation with less root mean square deviation value in comparison to the microcrystalline complex. Thus, the LAC complex has more hydrogen bonds and it was more stable as compared with the MCC complex. Therefore, VCH and used excipients could be used for solid dose formulations.

Liquid Nuclear Magnetic Resonance (NMR) Spectroscopy in Transition—From Structure Elucidation to Multi-Analysis Method

As early as 1946, Felix Bloch and Edward Mills Purcell detected nuclear magnetic resonance signals, earning themselves the Nobel Prize in 1952. The same year saw the launch of the first commercial nuclear magnetic resonance (NMR) spectrometer. Since then, NMR has experienced significant progress in various fields of application. While in the 1970s NMR spectroscopy was solely employed for determining the structure and purity of synthesis products in the chemical field, it gradually gained popularity in the medical field for the investigation and rendering of images of human organs. Since then, the technique has developed significantly in terms of stability, reproducibility, and sensitivity, thereby forming the foundation for high-resolution imaging, the automation or standardization of analytical procedures, and the application of chemometric methods, particularly in relation to identifying food adulteration. This review objectively assesses the current state of implementing liquid NMR in the food, cosmetics, and pharmaceutical industries. Liquid NMR has transitioned from a structural elucidation tool to a widely recognized, multi-analytical method that incorporates multivariate techniques. The illustrations and sources provided aim to enhance novice readers’ understanding of this topic.

Noncovalent modification induced 2D planar stacking: A promising strategy for high-energy insensitive materials

Exploring new energetic materials with high energy and high stability is a long-term goal in the field of energetic materials. Crystal engineering is recognized to be a promising strategy for balancing energy capability and safety. In this study, newly designed 1:1 energetic salt (compound 2) constructed by pairing 3-amino-4-(4,5-diamino-1,2,4-triazole-3-yl)-furazan with 4-amino-1,2,5-oxadiazole-3-carboxylic acid was achieved by the simple acid−base reaction method. The structure of target compound was determined and characterized by nuclear magnetic resonance (NMR) spectrometers, Infrared (IR) spectroscopy, differential scanning calorimetry (DSC), simultaneous thermal analyzer (TGA-DSC) and single-crystal X-ray diffraction. It was found that compound 2 possesses desirable face-to-face π-stacking, which promote molecular stability. The structure-property relationship was investigated from experimental results and quantum chemical calculations. The ideal structure gives rise to high energetic performances (D = 8545 m s−1; P = 30.4 GPa), good thermal stability (Td = 236.6 ℃) and low sensitivity (IS = 34 J, FS = 350 N). These fascinating results suggesting that two dimension (2D) planar stacking could effectively modulate energy and safety.

Characterization of fatty acid forms using benchtop NMR in omega-3 oil supplements.

Omega-3 fatty acid supplements, such as fish oil and plant-based oils, have gained popularity because of their potential health benefits. However, the quality and composition of these supplements can vary widely, particularly in terms of the two main forms of omega-3 fatty acids: triacylglycerols (TAGs) and ethyl esters (EEs). TAGs are the natural form found in fish oil but are prone to oxidation, whereas EEs are more stable but less well absorbed by the body. Differentiating between these forms is crucial for assessing the efficacy and tolerance of omega-3 supplements. This article describes a novel approach to differentiate between TAG and EE forms of omega-3 fatty acids in dietary supplements, utilizing a 60-MHz benchtop nuclear magnetic resonance (NMR) spectrometer. The proposed method using 1H and 1H-1H COSY NMR provides a quick and accurate approach to screen the forms of omega-3 fatty acids and evaluate their ratios. The presence of diacylglycerol (DAGs) in some supplements was also highlighted by this method and adds some information about the process used (i.e., esterification/enrichment). The affordability and user-friendliness of benchtop NMR equipment make this method feasible for food processing companies or quality control laboratories. In this study, 24 oil supplements were analyzed using NMR analysis in order to demonstrate the potential of this method for the differentiation of TAG and EE forms in omega-3 supplements.

Research of integrated shimming Halbach magnet for High strength, compact Benchtop NMR device

Due to production and assembly errors of magnets resulting in reduced magnetic field homogeneity, passive shimming (PS) is necessary when Halbach magnets are used in high-resolution Benchtop Nuclear Magnetic Resonance (BNMR) spectrometer. The conventional PS technique, which places independent PS devices inside the magnet aperture, is no longer applicable to small-aperture compact high-field-strength Halbach magnet studies. In this paper, based on spherical harmonic function expansion, we improve the magnetic field homogeneity by optimizing the moving step of the magnet moving arrays composed of Halbach magnets to generate the corresponding harmonic terms to compensate for the magnetic field. With this approach, the homogeneity of a 1 T Halbach magnet was improved from the original 3913 ppm to 8 ppm in a L10 mm × R2.5 mm of 0.64% copper sulfate doped water sample. This work explores the PS mechanism based on the movement of magnetic blocks, which can be applied in BNMR and other compact high-field strength high-homogeneity Halbach magnets application circumstances.