Solvent-free semihydrogenation of acetylene alcohols in a capillary reactor coated with a Pd-Bi/TiO2 catalyst

© 2016 Elsevier B.V. All rights reserved. A solvent-free semihydrogenation of 2-methyl-3-butyn-2-ol (MBY) to 2-methyl-3-buten-2-ol was performed in a capillary reactor (10 m long, 0.53 mm i.d.) coated with a titania supported Pd-Bi catalyst. Several coatings with different Pd/Bi ratio have been prepared. The catalysts have been characterized with SEM, TEM, EDX, XRD analysis and N 2 adsorption-desorption measurements. The maximum alkene yield of 90% was obtained at a molar Pd/Bi ratio of 11. The yield was increased to 95% in the presence of 10 mol.% pyridine in the reaction mixture. The alkene selectivity decreased with time due to leaching of Bi. The leaching was fully suppressed in the presence of 1 vol.% acetic acid in the reaction mixture. The catalyst remained stable for 100 h of continuous operation. The results demonstrate that capillary reactors provide alkene selectivity the same compared to ideal stirred tank batch reactors

Neurophysiological prognostic factors of motor function and spasticity after stroke

Purpose: Understanding the neural mechanisms of recovery of motor control and development of spasticity after stroke is paramount importance for neurorehabilitation.Methods: For this purpose, we have analyzed several TMS and EEG variables and their association with motor recovery and development of spasticity. Forty-two subjects with stroke have taken part in the investigation. The neurophysiological examination included assessments by transcranial magnetic stimulation (TMS), intra- and inter-hemispheric EEG coherence in different frequency bands (e.g. Theta (4.0–7.99 Hz)) as determined by quantitative electroencephalography (qEEG). Motor function has been measured by Fugl-Meyer (FM), spasticity has been measured by modified Ashworth scale. Multiple univariate and multivariate linear regression analyses have been performed to identify the predictors for motor function and spasticity.Results: Univariate analyses have shown a significant interaction of amplitude and motor threshold (MT) of injured and MT, central motor conduction time of uninjured hemisphere with motor function according to Fugle-Meyer (FM). Also significant interaction has been shown between MT of injured hemisphere and spasticity.Multivariate analyses have shown a significant interaction of MT and beta coherence in injured, uninjured hemisphere and interhemispheric in prediction of motor function by FM. Also significant interaction of MT of injured hemisphere, delta and theta coherence between C3-C4 and spasticity has been shown.These interaction suggests that higher beta activity in the lesioned hemisphere strengthens the association between MT and FM scores. Higher beta activity in the uninjured hemisphere strengthens the association between MT and FM scores. Higher interhemispheric beta activity between C3-C4 strengthens the association between MT and FM scores. Higher delta and theta interhemispheric activity between C3-C4 strengthens the association between MT and Ashworth scores.Conclusions: Our results suggest that MT of both hemispheres is the strongest predictors of motor recovery after stroke. Moreover, cortical activity in the injured and uninjured hemisphere measured by qEEG provides additional information, specifying the association between MT and FM scores. MT of injured hemisphere in the association with low-frequency cortical activity are the strongest predictors of spasticity after stroke.Thus, the combination of EEG and TMS in predicting the recovery of motor control after stroke provides additional opportunities in the study of nonlinear relationships of influencing the interhemispheric networks, uninjured hemisphere and the release of subcortical activit

Diffraction efficiency of photothermoplastic layers for the recording of discrete holograms

An experimental and theoretical study of the dependence of eta of a digital phase Fourier hologram of a point object on the amount of deformation delta and the discrete-structure parameters representing the hologram is detailed. An expression is given for eta. Experiments were performed on photothermoplastic layers based on polyvinyl carbazole and trinitrofluorenone charge transfer complexes. The maximum eta, 2%, is found at delta = 0.56 micron

Scale up study of capillary microreactors in solvent-free semihydrogenation of 2‐methyl‐3‐butyn‐2‐ol

A 2.5 wt.% Pd/ZnO catalytic coating has been deposited onto the inner wall of capillary reactors with a diameter of 0.53 and 1.6 mm. The coatings were characterised by XRD, SEM, TEM and elemental analysis. The performance of catalytic reactors was studied in solvent-free hydrogenation of 2-methyl-3-butyn-2-ol. No mass transfer limitations was observed in the reactor with a diameter of 0.53 mm up to a catalyst loading of 1.0 kg (Pd) m −3 . The activity and selectivity of the catalysts has been studied in a batch reactor to develop a kinetic model. The kinetic model was combined with the reactor model to describe the obtained data in a wide range of reaction conditions. The model was applied to calculate the range of reaction conditions to reach a production rate of liquid product of 10–50 kg a day in a single catalytic capillary reactor

Unmanned Aerial Systems for Magnetic Survey

Placing a magnetometer on unmanned aerial vehicle (UAV) seems to be an easy task as the sensor is rather lightweight in comparison with other geophysical sensors. But, the realization of an unmanned aeromagnetic system (UAMS) faces multiple technical complications, and, as a result, very few of many attempts to build a UAMS have succeeded. Even less projects have produced results of real magnetic survey. Different platforms (helicopters, multirotor, and fixed wing UAVs) and different kinds of magnetometers for UAMS have different pros and cons for the purpose. For the quality of magnetic survey, the most important is the issue of a platform’s (UAV) magnetic noise and its influence on a magnetic sensor. Workbench experimental studies as well as results of magnetic surveys with multirotor UAMS in Leningrad region, Republic Sakha-Yakutia, and Kazakhstan demonstrate solutions facilitating state-of-the-art high-quality measurements of magnetic anomalies for geological, archeological, and other purposes

Palladium-bismuth intermetallic and surface-poisoned catalysts for the semi-hydrogenation of 2-methyl-3-butyn-2-ol

The effects of poisoning of Pd catalysts with Bi and annealing in a polyol (ethylene glycol) were studied on the semi-hydrogenation of 2-methyl-3-butyn-2-ol (MBY). An increase in the Pd:Bi ratio from 7 to 1 in the Bi-poisoned catalysts decreased the hydrogenation activity due to blocking of active sites, but increased maximum alkene yield from 91.5% for the Pd catalyst to 94–96% for all Bi-poisoned Pd catalysts, by decreasing the adsorption energy of alkene molecules and suppressing the formation of β-hydride phase. Annealing of the catalysts induced the formation of intermetallic phases and decreased its activity due to sintering of the catalytic particles and low activity of intermetallic compounds. Langmuir–Hinshelwood kinetic modelling of the experimental data showed that poisoning of Pd with Bi changed the relative adsorption constants of organic species suggesting ligand effects at high Bi content