Research on Additives Assisted Catalytic Cyclo-Dehydration of 1, 4-Butanediol to Tetrahydrofuran in Near-Critical Water

2012 ◽  
Vol 550-553 ◽  
pp. 693-698 ◽  
Author(s):  
Yan Yang ◽  
Li Yi Dai ◽  
Jin Shou Wang ◽  
Hong Yan Zhou
Keyword(s):  
Catalytic Activity ◽  
Reaction Mechanism ◽  
Maximum Yield ◽  
Experimental Results ◽  
Time Range ◽  
Temperature Range ◽  
Experimental Parameters ◽  
Increasing Temperature ◽  
Water Ratio

We herein report the cyclo-dehydration of 1,4-butanediol (BD) assisted with additives to form tetrahydrofuran (THF) in near-critical water (NCW).Three additives including Fe2(SO4)3,ZnSO4 and NaHSO4 were screened. Effects of various experimental parameters such as temperature (260-340°C), time (60-180min), reactant/water ratio (r/w, 1:10-1:40) and pressure (15-25MPa) on the yield of THF were examined. Without the presence of additives, the results showed that increasing temperature favored the cyclo-dehydration of BD to form THF. The maximum yield (52.61 wt. %) was obtained at temperature of 340°C and time of 180 min. With the presence of additives, at temperature range of 260~300°C and time range of 60~130min, all the additives selected can promote the cyclo-dehydration of BD to yield THF. However, with further increasing temperature and time, the additives would suppress the formation of THF. The catalytic activity toward the production of THF in the order of Fe2(SO4)3> ZnSO4> NaHSO4. The maximum yield of THF assisted with Fe2(SO4)3 could reach as high as 59.85 wt. % at 320°C, 120 min. Large reactant/water ratio would not benefit the yield of THF because of the dilution of additive. Increasing the pressure will slightly increase the yield of THF. Base on experimental results, a possible reaction mechanism and pathway of dehydration of BD was proposed in NCW.

scholarly journals A Digital Improvement—Trimming a Digital Temperature Sensor with EEPROM Reprogrammable Fuses

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1700
Author(s):  
Anca Mihaela Vasile (Dragan) ◽  
Alina Negut ◽  
Adrian Tache ◽  
Gheorghe Brezeanu
Keyword(s):  
Standard Deviation ◽  
Power Supply ◽  
Temperature Sensor ◽  
Experimental Results ◽  
Temperature Error ◽  
Thermal Sensor ◽  
Memory Cells ◽  
Temperature Range ◽  
Read Only Memory ◽  
Digital Temperature Sensor

An EEPROM (electrically erasable programmable read-only memory) reprogrammable fuse for trimming a digital temperature sensor is designed in a 0.18-µm CMOS EEPROM. The fuse uses EEPROM memory cells, which allow multiple programming cycles by modifying the stored data on the digital trim codes applied to the thermal sensor. By reprogramming the fuse, the temperature sensor can be adjusted with an increased trim variation in order to achieve higher accuracy. Experimental results for the trimmed digital sensor showed a +1.5/−1.0 ℃ inaccuracy in the temperature range of −20 to 125 ℃ for 25 trimmed DTS samples at 1.8 V by one-point calibration. Furthermore, an average mean of 0.40 ℃ and a standard deviation of 0.70 ℃ temperature error were obtained in the same temperature range for power supply voltages from 1.7 to 1.9 V. Thus, the digital sensor exhibits similar performances for the entire power supply range of 1.7 to 3.6 V.

scholarly journals Ring-Opening Copolymerization of Cyclohexene Oxide and Cyclic Anhydrides Catalyzed by Bimetallic Scorpionate Zinc Catalysts

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1651
Author(s):  
Felipe de la Cruz-Martínez ◽  
Marc Martínez de Sarasa Buchaca ◽  
Almudena del Campo-Balguerías ◽  
Juan Fernández-Baeza ◽  
Luis F. Sánchez-Barba ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Mechanism ◽  
Catalytic System ◽  
Phthalic Anhydride ◽  
Ring Opening ◽  
High Selectivity ◽  
Zinc Complexes ◽  
Cyclohexene Oxide ◽  
Reaction Conditions ◽  
Cyclic Anhydrides

The catalytic activity and high selectivity reported by bimetallic heteroscorpionate acetate zinc complexes in ring-opening copolymerization (ROCOP) reactions involving CO2 as substrate encouraged us to expand their use as catalysts for ROCOP of cyclohexene oxide (CHO) and cyclic anhydrides. Among the catalysts tested for the ROCOP of CHO and phthalic anhydride at different reaction conditions, the most active catalytic system was the combination of complex 3 with bis(triphenylphosphine)iminium as cocatalyst in toluene at 80 °C. Once the optimal catalytic system was determined, the scope in terms of other cyclic anhydrides was broadened. The catalytic system was capable of copolymerizing selectively and efficiently CHO with phthalic, maleic, succinic and naphthalic anhydrides to afford the corresponding polyester materials. The polyesters obtained were characterized by spectroscopic, spectrometric, and calorimetric techniques. Finally, the reaction mechanism of the catalytic system was proposed based on stoichiometric reactions.

scholarly journals Cell mechanical properties of human breast carcinoma cells depend on temperature

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christian Aermes ◽  
Alexander Hayn ◽  
Tony Fischer ◽  
Claudia Tanja Mierke
Keyword(s):  
Mechanical Properties ◽  
Power Law ◽  
Cell Mechanics ◽  
Cell Types ◽  
Creep Response ◽  
Temperature Range ◽  
Myosin Filaments ◽  
Cell Mechanical Properties ◽  
Increasing Temperature ◽  
Mcf 7

AbstractThe knowledge of cell mechanics is required to understand cellular processes and functions, such as the movement of cells, and the development of tissue engineering in cancer therapy. Cell mechanical properties depend on a variety of factors, such as cellular environments, and may also rely on external factors, such as the ambient temperature. The impact of temperature on cell mechanics is not clearly understood. To explore the effect of temperature on cell mechanics, we employed magnetic tweezers to apply a force of 1 nN to 4.5 µm superparamagnetic beads. The beads were coated with fibronectin and coupled to human epithelial breast cancer cells, in particular MCF-7 and MDA-MB-231 cells. Cells were measured in a temperature range between 25 and 45 °C. The creep response of both cell types followed a weak power law. At all temperatures, the MDA-MB-231 cells were pronouncedly softer compared to the MCF-7 cells, whereas their fluidity was increased. However, with increasing temperature, the cells became significantly softer and more fluid. Since mechanical properties are manifested in the cell’s cytoskeletal structure and the paramagnetic beads are coupled through cell surface receptors linked to cytoskeletal structures, such as actin and myosin filaments as well as microtubules, the cells were probed with pharmacological drugs impacting the actin filament polymerization, such as Latrunculin A, the myosin filaments, such as Blebbistatin, and the microtubules, such as Demecolcine, during the magnetic tweezer measurements in the specific temperature range. Irrespective of pharmacological interventions, the creep response of cells followed a weak power law at all temperatures. Inhibition of the actin polymerization resulted in increased softness in both cell types and decreased fluidity exclusively in MDA-MB-231 cells. Blebbistatin had an effect on the compliance of MDA-MB-231 cells at lower temperatures, which was minor on the compliance MCF-7 cells. Microtubule inhibition affected the fluidity of MCF-7 cells but did not have a significant effect on the compliance of MCF-7 and MDA-MB-231 cells. In summary, with increasing temperature, the cells became significant softer with specific differences between the investigated drugs and cell lines.

Design of Magnetic Levitated Thrust Bearing Experiment Table

2011 ◽  
Vol 199-200 ◽  
pp. 597-602
Author(s):  
Shou Fa Liu ◽  
Zhang Jie Shi ◽  
Chun Feng Li
Keyword(s):  
Thrust Bearing ◽  
Deformation Measurement ◽  
Experimental Results ◽  
Electromagnetic Parameters ◽  
Ansys Simulation ◽  
Overall Design ◽  
Experimental Parameters ◽  
Structural Dimensions ◽  
Simulation Results

In this paper, the overall design of magnetic levitated thrust bearing experiment table was completed, of which the main experimental parameters those are electromagnetic parameters and structural dimensions were determined, in addition, the joint debugging and deformation measurement are performed. Analysis results showed that theoretical value, ANSYS simulation results and experimental results were similar, which said that it is feasible to perform stiffness check of the thrust collar on the experiment table.

An Ultrafast Vitrification Method for Cell Cryopreservation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Fengmin Su ◽  
Nannan Zhao ◽  
Yangbo Deng ◽  
Hongbin Ma
Keyword(s):  
Thin Film ◽  
Cooling Rate ◽  
Experimental Results ◽  
Low Concentration ◽  
Temperature Range ◽  
Thin Film Evaporation ◽  
Film Evaporation ◽  
A Cell ◽  
Cryoprotective Solution ◽  
Ultrafast Cooling

Ultrafast cooling is the key to successful cell vitrification cryopreservation of lower concentration cryoprotective solution. This research develops a cell cryopreservation methodology which utilizes thin film evaporation and achieves vitrification of relatively low concentration cryoprotectant with an ultrafast cooling rate. Experimental results show that the average cooling rate of dimethylsulfoxide (DMSO) cryoprotective solution reaches 150,000 °C/min in a temperature range from 10 °C to −180 °C. The ultrafast cooling rate can remarkably improve the vitrification tendencies of the cryoprotective solution. This methodology opens the possibility for more successful cell vitrification cryopreservation.

Influence of Temperature on Hydraulic Conductivity in Compacted Bentonite

1997 ◽  
Vol 506 ◽  
Author(s):  
W. J. Cho ◽  
J. O. Lee ◽  
K. S. Chun
Keyword(s):  
Hydraulic Conductivity ◽  
Influence Of Temperature ◽  
Temperature Range ◽  
Compacted Bentonite ◽  
Influence Of Temperature On ◽  
Water Saturated ◽  
Increasing Temperature ◽  
Good Agreement

ABSTRACTThe hydraulic conductivities in water saturated bentonites at different densities were measured within temperature range of 20 to 80 °C. The results show that the hydraulic conductivities increase with increasing temperature. The hydraulic conductivities of bentonites at the temperature of 80 °C increase up to about 3 times as high as those at 20 °C. The measured values are in good agreement with those predicted. The change in viscosity of water with temperature contributes greatly to increase of hydraulic conductivity.

Liquid-Phase Hydrogenation to 2, 4-Tolylenediamine over Supported HY Catalysts

2012 ◽  
Vol 512-515 ◽  
pp. 2381-2385
Author(s):  
Xue Mei Zhang ◽  
Feng Xing Niu
Keyword(s):  
Catalytic Activity ◽  
Liquid Phase ◽  
Catalytic Hydrogenation ◽  
Active Component ◽  
Experimental Results ◽  
Mass Ratio ◽  
Liquid Phase Hydrogenation ◽  
Catalytic Test

We have successfully prepared a novel passivation Ni/HY catalyst by the technologies of macerate-precipitatio.The catalysts are comprised of two contents: HY as carrier, Ni as active component，and we put it into the process of preparating aromatic amines.The nature of the catalysts was discussed based on the characterization results of BET , IR , SEM , XRD , TEM ,TPD , XPS and TPR . The catalytic hydrogenation technology for 2,4-dinitrobenzene in liquid phase can be an attractive and elegant routine for production of 2,4-tolylenediamine. The catalytic activity is evaluated at 2.2 MPa, 90 °C, 750r/min, solvent with reaction materials mass ratio of 60, catalyst with reaction materials mass ratio of 0.1. In the catalytic test, The experimental results over the catalyst showed that 2,4-dinitrobenzene and 2,4-tolylenediamine conversion and selective of 99.88% and 99.16% were obtained respectively.It is found that the catalyst is highly dispersion, stable, and reusable. No obvious deactivation of the catalyst was observed after repeated using twelve times.

scholarly journals A Method for Measuring the Weak Value of Spin for Metastable Atoms

Entropy ◽  
2018 ◽  
Vol 20 (8) ◽  
pp. 566 ◽  
Author(s):  
Robert Flack ◽  
Vincenzo Monachello ◽  
Basil Hiley ◽  
Peter Barker
Keyword(s):  
Accurate Determination ◽  
Experimental Results ◽  
Weak Value ◽  
Helium Atoms ◽  
Experimental Parameters ◽  
Helium Neon ◽  
Impulsive Approximation ◽  
Full Simulation ◽  
23S1 State

A method for measuring the weak value of spin for atoms is proposed using a variant of the original Stern–Gerlach apparatus. A full simulation of an experiment for observing the real part of the weak value using the impulsive approximation has been carried out. Our predictions show a displacement of the beam of helium atoms in the metastable 23S1 state, Δw, that is within the resolution of conventional microchannel plate detectors indicating that this type of experiment is feasible. Our analysis also determines the experimental parameters that will give an accurate determination of the weak value of spin. Preliminary experimental results are shown for helium, neon and argon in the 23S1 and 3P2 metastable states, respectively.

An anomaly in the specific heat below 3 °K of copper containing hydrogen

1969 ◽  
Vol 47 (14) ◽  
pp. 1485-1491 ◽  
Author(s):  
Neil Waterhouse
Keyword(s):  
Specific Heat ◽  
Molecular Hydrogen ◽  
Pure Copper ◽  
Solid Hydrogen ◽  
Rotational State ◽  
Experimental Results ◽  
Ortho Hydrogen ◽  
Temperature Range ◽  
A Value ◽  
Heat Curve

The specific heat of copper heated in hydrogen at 1040 °C has been measured over the temperature range 0.4 to 3.0 °K and found to be anomalous. The anomaly occurs in the same temperature range as the solid hydrogen λ anomaly which, in conjunction with evidence of ortho to para conversion of hydrogen in the sample, suggests the presence of molecular hydrogen in the copper. The anomaly reported by Martin for "as-received" American Smelting and Refining Company (ASARCO) 99.999+ % pure copper has been briefly compared with the present results. The form of the anomaly produced by the copper-hydrogen specimen has been compared with Schottky curves using the simplest possible model, that for two level splitting of the degenerate J = 1 rotational state of the ortho-hydrogen molecule.Maintenance of the copper-hydrogen sample at ~20 °K for approximately 1 week removed the "hump" in the specific heat curve. An equation of the form Cp = γT + (464.34/(θ0c)3)T3 was found to fit these experimental results and produced a value for γ which had increased over that for vacuumannealed pure copper by ~2%.

The effect of defects on the catalytic activity of single Au atom supported carbon nanotubes and reaction mechanism for CO oxidation

2017 ◽  
Vol 19 (33) ◽  
pp. 22344-22354 ◽  
Author(s):  
Sajjad Ali ◽  
Tian Fu Liu ◽  
Zan Lian ◽  
Bo Li ◽  
Dang Sheng Su
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional Theory ◽  
Catalytic Activity ◽  
Carbon Nanotube ◽  
Reaction Mechanism ◽  
Co Oxidation ◽  
Density Functional ◽  
Functional Theory ◽  
Single Walled Carbon Nanotube ◽  
Wales Defect

The mechanism of CO oxidation by O2 on a single Au atom supported on pristine, mono atom vacancy (m), di atom vacancy (di) and the Stone Wales defect (SW) on single walled carbon nanotube (SWCNT) surface is systematically investigated theoretically using density functional theory.

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