scholarly journals Kinetics of NiO and NiCl2Hydrogen Reduction as Precursors and Properties of Produced Ni/Al2O3and Ni-Pd/Al2O3Catalysts

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Miroslav Sokić ◽  
Željko Kamberović ◽  
Vesna Nikolić ◽  
Branislav Marković ◽  
Marija Korać ◽  
...  
Keyword(s):  
Metal Content ◽  
Hydrogen Reduction ◽  
Effect Of Temperature ◽  
Synthesis Process ◽  
Reduction Temperature ◽  
Time Intervals ◽  
Reduction Processes ◽  
Calcination Step ◽  
Before And After ◽  
Kinetics Of

The objects of this investigation were the comparative kinetic analysis of the NiO and NiCl2reduction by hydrogen during an induction period and elimination of the calcination during the synthesis of Ni/Al2O3catalysts. The effect of temperature and time on NiO and NiCl2reduction degrees was studied. Avrami I equation was selected as the most favorable kinetic model and used to determine activation energy of the NiO and NiCl2reduction for the investigated temperature range (623–923 K) and time intervals (1–5 minutes). The investigation enabled reaching conclusions about the reaction ability and rate of the reduction processes. Afterward, Ni/Al2O3catalysts were obtained by using oxide and chloride precursor for Ni. The catalysts were supported on alumina-based foam and prepared via aerosol route. Properties of the samples before and after low-temperature hydrogen reduction (633 K) were compared. Obtained results indicated that the synthesis of Ni/Al2O3catalysts can be more efficient if chloride precursor for Ni is directly reduced by hydrogen during the synthesis process, without the calcination step. In addition, Ni-Pd/Al2O3catalysts with different metal content were prepared by using chloride precursors. Lower reduction temperature was utilized and the chlorides were almost completely reduced at 533 K.

A Description of the Kinetics and Mechanisms which Control the Release of Hlw Elements from Synroc

1990 ◽  
Vol 212 ◽  
Author(s):  
K. L. Smith ◽  
K. P. Hart ◽  
G. R. Lumpkin ◽  
P. McGlinn ◽  
P. Lam ◽  
...  
Keyword(s):  
Emission Spectroscopy ◽  
Optical Emission Spectroscopy ◽  
Optical Emission ◽  
Effect Of Temperature ◽  
Secondary Phases ◽  
Surface Layers ◽  
Before And After ◽  
Bicarbonate Solutions ◽  
Icp Mass Spectrometry ◽  
Kinetics Of

ABSTRACTLeaching tests were carried out on well-characterised Synroc C specimens containing 10 wt% simulated HLW. The effect of temperature and leachant composition on the mechanisms and kinetics of leaching were investigated by leaching Synroc specimens in deionised water at 70°C and 150°C, and in silicate and bicarbonate solutions at 70°C. SEM and TEM were used before and after leaching to characterise the primary and secondary phases in and on the Synroc samples, and to describe the morphological and chemical changes which occurred. Leachants were analysed using ICP/optical emission spectroscopy and ICP/mass spectrometry.Titaniferous surface layers were observed on the surface after exposure to leachants. Analysis of the leaching data has established that these surface layers can reduce the release of HLW elements from Synroc and that variations in temperature and leachant composition can hinder or promote the formation of secondary phases.

scholarly journals Montmorillonite immobilized Fe/Ni bimetallic prepared by dry in-situ hydrogen reduction for the degradation of 4-Chlorophenlo

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shuo-Shuo Zhang ◽  
Ning Yang ◽  
Xuming Zhuang ◽  
Liying Ren ◽  
Vinothkumar Natarajan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Bimetallic Nanoparticles ◽  
Hydrogen Reduction ◽  
Maximum Activity ◽  
Synthesis Process ◽  
Reduction Temperature ◽  
Liquid Environment ◽  
X Ray ◽  
Ni Content

Abstract This study puts forward a new way to produce montmorillonite immobilized bimetallic nickel-iron nanoparticles by dry in-situ hydrogen reduction method in the non-liquid environment, which effectively inhibits the oxidation of iron and nickel during the synthesis process and improves the reactivity of the material. The degradation of 4-Chlorophenol (4-CP) was investigated to examine the catalytic activity of the material. The morphology and crystal properties of the montmorillonite-templated Fe/Ni bimetallic particles were explored by using scanning electron microscopy, transmission electron microscopy, X-ray diffraction studies, and energy dispersive X-ray spectroscopy analysis. Results suggest that Fe and Ni particles were homogeneously dispersed on the montmorillonite. The optimization of Ni content and reduction temperature over the degradation of 4-CP was also studied. The introduction of Ni intensely improved the degradation of 4-CP and reached over 90% when Ni content was 28.5%. The degradation rate increased significantly with the increase of reduction temperature and showed maximum activity at the reduction tempreature of 800 °C. This study offers a new method to fabricate montmorillonite immobilized Fe/Ni bimetallic nanoparticles in the non-liquid environment and the composites exhibited high degradation activity to chlorinated organic compounds.

scholarly journals Modelling the kinetics of water loss during deep-fat frying of potato particulates

2014 ◽  
Vol 32 (No. 6) ◽  
pp. 585-594 ◽  
Author(s):  
P.-Y.H. Huang ◽  
Y.-Ch. Fu
Keyword(s):  
Water Loss ◽  
Structural Changes ◽  
Effect Of Temperature ◽  
Order Kinetic ◽  
Deep Fat Frying ◽  
First Order ◽  
Before And After ◽  
Order Kinetic Model ◽  
Rate Processes ◽  
Kinetics Of

We developed an empirical model to describe the water loss during deep-fat frying. Raw potato particulates were sliced to form cylinders and subjected to the deep-fat frying at isothermal temperatures of 160, 190, and 220&deg;C. The microstructure properties were assessed by Field Emission Scanning Electron Microscope (FESEM). The plot of the water content versus the frying time showed two distinct regions. A first-order kinetic model correlated with the two irreversible serial rate processes, rapid process and slow process, was hypothesised to describe the water loss during frying. The results showed the simultaneous two first-order kinetic models adequately predicted the water loss of potato particulates during isothermal frying. The effect of temperature on the rate constants, k<sub>1</sub> and k<sub>2</sub>, for the two processes was adequately modelled by the Arrhenius relationship. The observations of structural changes on the surface and in the inner section of potato particulates are critical. These physical pieces of evidence support our assumption that the mechanisms of the water loss (two-stage rate processes) before and after the transition time are different. &nbsp;

Effect of temperature during the synthesis process of CdSe nanoparticles using the colloidal technique

MRS Advances ◽  
2020 ◽  
Vol 5 (63) ◽  
pp. 3389-3395
Author(s):  
R. González-Díaz ◽  
D. Fernández-Sánchez ◽  
P. Rosendo-Francisco ◽  
G. Sánchez-Legorreta
Keyword(s):  
Scanning Tunneling Microscope ◽  
Electron Cloud ◽  
Cdse Nanoparticles ◽  
Effect Of Temperature ◽  
Synthesis Process ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
First Results ◽  
Effects Of Temperature ◽  
Scanning Electron

AbstractIn this work, the first results of the effects of temperature during the production of Se2- ions and the effect during the interaction of Cd2+ and Se2- ions in the synthesis process of CdSe nanoparticles are presented. The synthesis of CdSe was carried out by the colloidal technique, in the first one we used a temperature of 63 °C to produce Se2- ions and in the second one an interaction temperature of 49 °C. The samples were characterized using a Scanning Electron Microscope (SEM) and a Scanning Tunneling Microscope (STM). From the SEM micrographs it was possible to identify the thorns formation and irregular islands. STM micrographs reveal elliptical shapes with a regular electron cloud profile.

Temperature Effect on the Two-Dimensional Phase Transition Kinetics of Adenine Adsorbed at the Hg Electrode/Aqueous Solution Interface

2003 ◽  
Vol 68 (8) ◽  
pp. 1407-1419 ◽  
Author(s):  
Claudio Fontanesi ◽  
Roberto Andreoli ◽  
Luca Benedetti ◽  
Roberto Giovanardi ◽  
Paolo Ferrarini
Keyword(s):  
Phase Transition ◽  
Aqueous Solution ◽  
Phase Change ◽  
Temperature Effect ◽  
Transition Rate ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Solution Interface ◽  
Phase Transition Kinetics ◽  
Kinetics Of

The kinetics of the liquid-like → solid-like 2D phase transition of adenine adsorbed at the Hg/aqueous solution interface is studied. Attention is focused on the effect of temperature on the rate of phase change; an increase in temperature is found to cause a decrease of transition rate.

scholarly journals Progression of cerebral infarction before and after thrombectomy is modified by prehospital pathways

2021 ◽  
pp. neurintsurg-2020-017155
Author(s):  
Alexander M Kollikowski ◽  
Franziska Cattus ◽  
Julia Haag ◽  
Jörn Feick ◽  
Alexander G März ◽  
...  
Keyword(s):  
Patient Characteristics ◽  
Large Vessel ◽  
Stroke Severity ◽  
Large Vessel Occlusion ◽  
Time Intervals ◽  
Vessel Occlusion ◽  
Before And After ◽  
Transferred Patients ◽  
Stroke Center

BackgroundEvidence of the consequences of different prehospital pathways before mechanical thrombectomy (MT) in large vessel occlusion stroke is inconclusive. The aim of this study was to investigate the infarct extent and progression before and after MT in directly admitted (mothership) versus transferred (drip and ship) patients using the Alberta Stroke Program Early CT Score (ASPECTS).MethodsASPECTS of 535 consecutive large vessel occlusion stroke patients eligible for MT between 2015 to 2019 were retrospectively analyzed for differences in the extent of baseline, post-referral, and post-recanalization infarction between the mothership and drip and ship pathways. Time intervals and transport distances of both pathways were analyzed. Multiple linear regression was used to examine the association between infarct progression (baseline to post-recanalization ASPECTS decline), patient characteristics, and logistic key figures.ResultsASPECTS declined during transfer (9 (8–10) vs 7 (6-9), p<0.0001), resulting in lower ASPECTS at stroke center presentation (mothership 9 (7–10) vs drip and ship 7 (6–9), p<0.0001) and on follow-up imaging (mothership 7 (4–8) vs drip and ship 6 (3–7), p=0.001) compared with mothership patients. Infarct progression was significantly higher in transferred patients (points lost, mothership 2 (0–3) vs drip and ship 3 (2–6), p<0.0001). After multivariable adjustment, only interfacility transfer, preinterventional clinical stroke severity, the degree of angiographic recanalization, and the duration of the thrombectomy procedure remained predictors of infarct progression (R2=0.209, p<0.0001).ConclusionsInfarct progression and postinterventional infarct extent, as assessed by ASPECTS, varied between the drip and ship and mothership pathway, leading to more pronounced infarction in transferred patients. ASPECTS may serve as a radiological measure to monitor the benefit or harm of different prehospital pathways for MT.

scholarly journals The influence of an external magnetic field on the dynamics of magnetite reduction with hydrogen

RSC Advances ◽  
2021 ◽  
Vol 11 (25) ◽  
pp. 15422-15427
Author(s):  
Petr A. Chernavsky ◽  
Nellie V. Kim ◽  
Victor A. Andrianov ◽  
Yurii D. Perfiliev ◽  
Alla A. Novakova ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Hydrogen Reduction ◽  
Kinetics Of

The kinetics of hydrogen reduction of magnetite was investigated in different magnetic fields.

scholarly journals Usefulness of Imaging Response Assessment after Irreversible Electroporation of Localized Pancreatic Cancer—Results from a Prospective Cohort

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2862
Author(s):  
Rasmus V. Flak ◽  
Rune V. Fisker ◽  
Niels H. Bruun ◽  
Mogens T. Stender ◽  
Ole Thorlacius-Ussing ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Irreversible Electroporation ◽  
Response Assessment ◽  
Time Intervals ◽  
Patient Level ◽  
Positron Emission ◽  
Included Patient ◽  
Before And After ◽  
Lesion Level ◽  
Level Analysis

(1) Background: Irreversible electroporation (IRE) is a nonthermal ablation technique that is being studied in nonmetastatic pancreatic cancer (PC). Most published studies use imaging outcomes as an efficacy endpoint, but imaging interpretation can be difficult and has yet to be correlated with survival. The aim of this study was to examine the correlation of imaging endpoints with survival in a cohort of IRE-treated PC patients. (2) Methods: Several imaging endpoints were examined before and after IRE on 18F-fluorodeoxyglucose positron emission tomography (PET) with computed tomography. Separate analyses were performed at the patient and lesion levels. Mortality rate (MR) ratios for imaging endpoints after IRE were estimated. (3) Results: Forty-one patients were included. Patient-level analysis revealed that progressive disease (PD), as defined by RECIST 1.1, is correlated with a higher MR at all time intervals, but PD, as defined by EORTC PET response criteria, is only correlated with the MR in the longest interval. No correlation was found between PD, as defined by RECIST, and the MR in the lesion-level analysis. (4) Conclusions: Patient-level PD, as defined by RECIST, was correlated with poorer survival after IRE ablation, whereas no correlations were observed in the lesion-level analyses. Several promising lesion-level outcomes were identified.

scholarly journals HPV and Cytology Testing in Women Undergoing 9-Valent HPV Opportunistic Vaccination: A Single-Cohort Follow Up Study

Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 643
Author(s):  
Rosa De Vincenzo ◽  
Nicola Caporale ◽  
Valentina Bertoldo ◽  
Caterina Ricci ◽  
Maria Teresa Evangelista ◽  
...  
Keyword(s):  
Pap Smear ◽  
Cox Regression ◽  
Vaccine Dose ◽  
Pap Smears ◽  
Adult Women ◽  
Sexually Active ◽  
Time Intervals ◽  
Dose Administration ◽  
Before And After ◽  
Single Cohort

Background: This study evaluates the possible effect of 9-valent (9vHPV) vaccination on the results of HPV and cytological tests in a cohort of adult women. Methods: This study is a retrospective, single-cohort, monocentric study. Sexually active women aged 14–70 years, who underwent 9vHPV vaccination, were enrolled. Dose administration dates, side effects and data on Pap smears and HPV tests performed before and after the first vaccine dose were collected. Subjects were considered “unexposed” to the vaccine for all time intervals before the first dose administration, and “exposed” to the first, second and third vaccine doses in all time intervals following each specific dose. Results: A total of 512 women underwent the first 9vHPV dose administration and were enrolled in the study. Median age at vaccination was 30.5 (14–70). Log-rank tests and Cox regression analyses showed a highly statistically significant (p < 0.0001) difference in the time to negativization after the exposure to the third vaccine dose in the 207 women starting with a Pap+ smear (HR (95% C.I.), 2.66 (1.83–3.86)) and in the 198 women starting with an HPV HR+ test (HR (95% C.I.), 7.80 (4.83–12.60)). Conclusions: 9vHPV vaccination may play a role in shortening the clearance time of HPV HR+ or Pap positivity in sexually active adult women.

Sign in / Sign up

Export Citation Format

Share Document