scholarly journals Continuous-Flow Synthesis of Thermochromic M-Phase VO2 Particles via Rapid One-Step Hydrothermal Reaction: Effect of Mixers

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Xiaojie Yan ◽  
William Trevillyan ◽  
Ioannina Castano ◽  
Yugang Sun ◽  
Ralph Muehleisen ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Hydrothermal Reaction ◽  
Xrd Analysis ◽  
Single Step ◽  
Hot Water ◽  
Scanning Calorimetry ◽  
Smart Windows ◽  
M Phase ◽  
One Step ◽  
Resident Time

VO2 particles are promising materials for thermochromic smart windows that reduce building energy loss. Continuous-flow hydrothermal processes showcase advantages for synthesizing VO2 particles compared with traditional batch reaction systems. Mixers play a crucial role in particle fabrication in continuous-flow systems. In this study, a Center T-Mixer and a Collision Cross-Mixer are developed and implemented in a hot water fluidized suspension reaction (HWFSR) system. The influence of the resident time on the particle phase and size was evaluated, and properties of particles derived from systems equipped with differing mixers were compared. The resulting particles were characterized using techniques of X-ray powder diffraction (XRD) analysis, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). When compared with the Center T-Mixer, results indicate that the Collision Cross-Mixer has better control regarding the morphology and size distribution of resulting particles while improving the transition temperatures of the as-synthesized materials. HWFSR systems containing novel mixer designs are capable of producing pure M-phase VO2 particles in a single step contrary to the current reactor design that use a second postheat treatment step, and they are capable of synthesizing many other nanoparticle species, especially those requiring high temperature and pressure reaction conditions.

scholarly journals Efficient Preparation and Performance Characterization of the HMX/F2602 Microspheres by One-Step Granulation Process

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Conghua Hou ◽  
Xinlei Jia ◽  
Jingyu Wang ◽  
Yingxin Tan ◽  
Yuanping Zhang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Stability ◽  
Particle Size ◽  
Particle Morphology ◽  
Xrd Analysis ◽  
Impact Sensitivity ◽  
Scanning Calorimetry ◽  
Granulation Process ◽  
One Step ◽  
The Impact

A new one-step granulation process for preparing high melting explosive- (HMX-) based PBX was developed. HMX/F2602 microspheres were successfully prepared by using HMX and F2602 as the main explosive and binder, respectively. The particle morphology, particle size, crystal structure, thermal stability, and impact sensitivity of the as-prepared HMX/F2602 microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer, differential scanning calorimetry (DSC), and impact sensitivity test, respectively. The SEM analysis indicated successful coating of F2602 on the surface of HMX, and the resulting particles are ellipsoidal or spherical with a median particle size of 940 nm; the XRD analysis did not show any change in the crystal structure after the coating and still has β-HNX crystal structure; according to the DSC analysis, HMX/F2602 prepared by the new method has better thermal stability compared to that prepared by the water suspension process. The impact sensitivity of HMX/F2602 prepared by this one-step granulation process decreased, and its characteristic height H50 increased from 37.62 to 40.13 cm, thus significantly improving the safety performance. More importantly, this method does not need the freeze-drying process after recrystallization, thus increasing the efficiency by 2 to 3 times.

scholarly journals One-step synthesis of pyridines and dihydropyridines in a continuous flow microwave reactor

2013 ◽  
Vol 9 ◽  
pp. 1957-1968 ◽  
Author(s):  
Mark C Bagley ◽  
Vincenzo Fusillo ◽  
Robert L Jenkins ◽  
M Caterina Lubinu ◽  
Christopher Mason
Keyword(s):  
Michael Addition ◽  
Continuous Flow ◽  
Flow Reactor ◽  
Acid Catalyst ◽  
Single Step ◽  
Continuous Processing ◽  
Microwave Reactor ◽  
One Step ◽  
Very High ◽  
Yielding Process

The Bohlmann–Rahtz pyridine synthesis and the Hantzsch dihydropyridine synthesis can be carried out in a microwave flow reactor or using a conductive heating flow platform for the continuous processing of material. In the Bohlmann–Rahtz reaction, the use of a Brønsted acid catalyst allows Michael addition and cyclodehydration to be carried out in a single step without isolation of intermediates to give the corresponding trisubstituted pyridine as a single regioisomer in good yield. Furthermore, 3-substituted propargyl aldehydes undergo Hantzsch dihydropyridine synthesis in preference to Bohlmann–Rahtz reaction in a very high yielding process that is readily transferred to continuous flow processing.

Mannose Conjugated Starch Nanoparticles for Preferential Targeting of Liver Cancer

2020 ◽  
Vol 17 ◽  
Author(s):  
Akhlesh Kumar Jain ◽  
Hitesh Sahu ◽  
Keerti Mishra ◽  
Suresh Thareja
Keyword(s):  
Side Effects ◽  
Liver Cancer ◽  
Entrapment Efficiency ◽  
Xrd Analysis ◽  
In Vitro Cytotoxicity ◽  
Physical Interaction ◽  
Scanning Calorimetry ◽  
Starch Nanoparticles

Aim: To design D-Mannose conjugated 5-Fluorouracil (5-FU) loaded Jackfruit seed starch nanoparticles (JFSSNPs) for site specific delivery. Background: Liver cancer is the third leading cause of death in world and fifth most often diagnosed cancer is the major global threat to public health. Treatment of liver cancer with conventional method bears several side effects, thus to undertake these side effects as a formulation challenge, it is necessary to develop novel target specific drug delivery system for the effective and better localization of drug into the proximity of target with restricting the movement of drug in normal tissues. Objective: To optimize and characterize the developed D-Mannose conjugated 5-Fluorouracil (5-FU) loaded Jackfruit seed starch nanoparticles (JFSSNPs) for effective treatment of liver cancer. Materials and methods: 5-FU loaded JFSSNPs were prepared and optimized formulation had higher encapsulation efficiency were conjugated with D-Mannose. These formulations were characterized for size, morphology, zeta potential, X-Ray Diffraction, and Differential Scanning Calorimetry. Potential of NPs were studied using in vitro cytotoxicity assay, in vivo kinetic studies and bio-distribution studies. Result and discussion: 5-Fluorouracil loaded NPs had particle size between 336 to 802nm with drug entrapment efficiency was between 64.2 to 82.3%. In XRD analysis, 5-FU peak was diminished in the diffractogram, which could be attributed to the successful incorporation of drug in amorphous form. DSC study suggests there was no physical interaction between 5- FU and Polymer. NPs showed sustained in vitro 5-FU release up to 2 hours. In vivo, mannose conjugated NPs prolonged the plasma level of 5-FU and assist selective accumulation of 5-FU in the liver (vs other organs spleen, kidney, lungs and heart) compared to unconjugated one and plain drug. Conclusion: In vivo, bio-distribution and plasma profile studies resulted in significantly higher concentration of 5- Fluorouracil liver suggesting that these carriers are efficient, viable, and targeted carrier of 5-FU treatment of liver cancer.

Synthesis of Polycycles and Oxacycles by Tandem Metathesis of endo–norbornene Derivatives

Synthesis ◽  
2021 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Sunil Pulletikurti ◽  
Ambareen Fatma ◽  
gopal dhangar ◽  
gonna somu Naidu
Keyword(s):  
Natural Products ◽  
Metal Complex ◽  
Carbonyl Group ◽  
Single Step ◽  
Time Dependent ◽  
Computational Studies ◽  
Nmr Studies ◽  
Tricyclic Compounds ◽  
One Step ◽  
Norbornene Derivatives

Here, we have demonstrated that the presence of a carbonyl group at C7 position is preventing the olefin metathesis of endo-norbornene derivatives due to the complexation of the metal alkylidene. Time-dependent NMR studies showed the presence of new proton signals in the metal alkylidene region, which indicate the formation of metal complex with the carbonyl group of the substrate. These observations were further proved by ESI-MS analysis. Whereas, computational studies provided that the catalyst was interacting with the C7 carbonyl group and aligned perpendicular to that of norbornene olefin. Later, these endo-keto norbornene derivatives were reduced to hydroxyl derivatives diastereoselectively. Ring-rearrangement metathesis (RRM) of these hydroxyl derivatives, produced the [6/5/6], and [5/6/5] carbo-tricyclic cores of the natural products in one step. Whereas the RRM of O-allyl derivatives, delivered the oxa-tricyclic compounds in a single step with excellent yields.

scholarly journals Synthesis and Polymerization Kinetics of Rigid Tricyanate Ester

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1686
Author(s):  
Andrey Galukhin ◽  
Roman Nosov ◽  
Ilya Nikolaev ◽  
Elena Melnikova ◽  
Daut Islamov ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Single Step ◽  
Polymerization Kinetics ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Diffusion Controlled ◽  
Polymerization Product ◽  
The One ◽  
Kinetics Of

A new rigid tricyanate ester consisting of seven conjugated aromatic units is synthesized, and its structure is confirmed by X-ray analysis. This ester undergoes thermally stimulated polymerization in a liquid state. Conventional and temperature-modulated differential scanning calorimetry techniques are employed to study the polymerization kinetics. A transition of polymerization from a kinetic- to a diffusion-controlled regime is detected. Kinetic analysis is performed by combining isoconversional and model-based computations. It demonstrates that polymerization in the kinetically controlled regime of the present monomer can be described as a quasi-single-step, auto-catalytic, process. The diffusion contribution is parameterized by the Fournier model. Kinetic analysis is complemented by characterization of thermal properties of the corresponding polymerization product by means of thermogravimetric and thermomechanical analyses. Overall, the obtained experimental results are consistent with our hypothesis about the relation between the rigidity and functionality of the cyanate ester monomer, on the one hand, and its reactivity and glass transition temperature of the corresponding polymer, on the other hand.

scholarly journals Study on Structure, Thermal Behavior, and Viscoelastic Properties of Nanodiamond-Reinforced Poly (vinyl alcohol) Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1426
Author(s):  
Tomáš Remiš ◽  
Petr Bělský ◽  
Tomáš Kovářík ◽  
Jaroslav Kadlec ◽  
Mina Ghafouri Azar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Single Step ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Primary Particles ◽  
Solution Casting Method ◽  
Average Size

In this work, advanced polymer nanocomposites comprising of polyvinyl alcohol (PVA) and nanodiamonds (NDs) were developed using a single-step solution-casting method. The properties of the prepared PVA/NDs nanocomposites were investigated using Raman spectroscopy, small- and wide-angle X-ray scattering (SAXS/WAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was revealed that the tensile strength improved dramatically with increasing ND content in the PVA matrix, suggesting a strong interaction between the NDs and the PVA. SEM, TEM, and SAXS showed that NDs were present in the form of agglomerates with an average size of ~60 nm with primary particles of diameter ~5 nm. These results showed that NDs could act as a good nanofiller for PVA in terms of improving its stability and mechanical properties.

scholarly journals Single Step 2-Port Device De-Embedding Algorithm for Fixture-DUT-Fixture Network Assembly

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1275
Author(s):  
Simone Scafati ◽  
Enza Pellegrino ◽  
Francesco de Paulis ◽  
Carlo Olivieri ◽  
James Drewniak ◽  
...  
Keyword(s):  
Standard Technique ◽  
Single Step ◽  
Scattering Parameters ◽  
Linear Set ◽  
S Parameter ◽  
Parameter Conversion ◽  
Before And After ◽  
One Step ◽  
Typical Measurement

The de-embedding of measurement fixtures is relevant for an accurate experimental characterization of radio frequency and digital electronic devices. The standard technique consists in removing the effects of the measurement fixtures by the calculation of the transfer scattering parameters (T-parameters) from the available measured (or simulated) global scattering parameters (S-parameters). The standard de-embedding is achieved by a multiple steps process, involving the S-to-T and subsequent T-to-S parameter conversion. In a typical measurement setup, two fixtures are usually placed before and after the device under test (DUT) allowing the connection of the device to the calibrated vector network analyzer coaxial ports. An alternative method is proposed in this paper: it is based on the newly developed multi-network cascading algorithm. The matrices involved in the fixture-DUT-fixture cascading gives rise to a non-linear set of equations that is in one step analytically solved in closed form, obtaining a unique solution. The method is shown to be effective and at least as accurate as the standard multi-step de-embedding one.

scholarly journals Hydrothermal synthesis of nanocrystalline hydroxyapatite–graphene nanosheet on Ti-6Al-7Nb: mechanical and in vitro corrosion performance

2021 ◽  
Vol 32 (4) ◽  
Author(s):  
Oktay Yigit ◽  
Burak Dikici ◽  
Niyazi Ozdemir
Keyword(s):  
Hydrothermal Reaction ◽  
Hybrid Coatings ◽  
Stoichiometric Ratio ◽  
Corrosion Performance ◽  
Graphene Nanosheet ◽  
Graphene Layers ◽  
Nanocrystalline Hydroxyapatite ◽  
One Step ◽  
Nano Size

AbstractThe hybrid coatings containing the graphene nano-sheet (GNS) and nano-hydroxyapatite (nHA) phases have been successfully synthesized on Ti6Al7Nb alloys by a one-step hydrothermal method. The hydrothermal reaction was carried out for 24 h at 200 °C. The GNS ratio has been altered as 1, 3, 5 and 7 wt.% in the coatings and, the results have compared with non- GNS containing coatings. The effect of the GNS ratio on the microstructure, hardness, and in vitro corrosion responses has been investigated in detail. The characterizations of the coatings were carried out by SEM, EDS, AFM, XRD and, FTIR. The corrosion behavior of the hybrid coatings was compared in Kokubo’s solution at 37 °C by using potentiodynamic polarization tests. The results showed that the hydroxyapatite phases were deposed on the graphene layers with nano-size nucleation with its Ca/P stoichiometric ratio. The best hydrophilicity (~52°) property has been obtained in nHA/3GNS coatings. In addition, the corrosion rates of coatings increased in the following order: nHA/3GNS < nHA/1GNS < nHA/7GNS < nHA/5GNS < only nHA.

scholarly journals Experimental Comparison of Innovative Composite Sorbents for Space Heating and Domestic Hot Water Storage

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 476
Author(s):  
Vincenza Brancato ◽  
Larisa G. Gordeeva ◽  
Angela Caprì ◽  
Alexandra D. Grekova ◽  
Andrea Frazzica
Keyword(s):  
Silica Gel ◽  
Xrd Analysis ◽  
Complete Characterization ◽  
Operating Conditions ◽  
Hot Water ◽  
Experimental Comparison ◽  
Space Heating ◽  
Calorimetric Analysis ◽  
Domestic Hot Water ◽  
Composite Sorbents

In this study, the development and comparative characterization of different composite sorbents for thermal energy storage applications is reported. Two different applications were targeted, namely, low-temperature space heating (SH) and domestic hot water (DHW) provision. From a literature analysis, the most promising hygroscopic salts were selected for these conditions, being LiCl for SH and LiBr for DHW. Furthermore, two mesoporous silica gel matrixes and a macroporous vermiculite were acquired to prepare the composites. A complete characterization was performed by investigating the porous structure of the composites before and after impregnation, through N2 physisorption, as well as checking the phase composition of the composites at different temperatures through X-ray powder diffraction (XRD) analysis. Furthermore, sorption equilibrium curves were measured in water vapor atmosphere to evaluate the adsorption capacity of the samples and a detailed calorimetric analysis was carried out to evaluate the reaction evolution under real operating conditions as well as the sorption heat of each sample. The results demonstrated a slower reaction kinetic in the vermiculite-based composites, due to the larger size of salt grains embedded in the pores, while promising volumetric storage densities of 0.7 GJ/m3 and 0.4 GJ/m3 in silica gel-based composites were achieved for SH and DHW applications, respectively.

Sign in / Sign up

Export Citation Format

Share Document