scholarly journals Measurement and Correlation of the Solubility of β-Cyclodextrin in Different Solutions at Different Temperatures and Thermodynamic Study of the Dissolution Process

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 135
Author(s):  
Shanshan Jin ◽  
Xuewei Cui ◽  
Yingping Qi ◽  
Yongfeng Shen ◽  
Hua Li

A new improved formulation was studied to improve the rehydration properties of freeze-dried dumplings. To provide basic data for industrial applications, the solubility capabilities of β-Cyclodextrin in sucrose, NaCl, and a mixed solution were measured at temperatures ranging from 303.15 to 353.15 K using a laser monitoring method. The experimental values indicated that the solubility of β-Cyclodextrin in solvents increased with increasing temperature. The simplified Apelblat model, Apelblat model, and λh model were employed to analyze the experimental results using correlation tests. The relative average deviation (RAD) values between the experimental and calculated values were less than 0.095, 0.075, and 0.103 for the simplified Apelblat equation, Apelblat equation, and λh equation, respectively. Apparent thermodynamic analysis of β-Cyclodextrin dissolution was also performed at the mean temperature using the model parameters of Apelblat equation. Furthermore, thermodynamic properties of the solution process, including the enthalpy, entropy, and Gibbs free energy, were also calculated and analyzed. This study provides the basic data for applications in industrial production, and is specifically of great significance for the improved formulation of freeze-dried dumplings.

Author(s):  
Charchit Kumar ◽  
Alejandro Palacios ◽  
Venkata A. Surapaneni ◽  
Georg Bold ◽  
Marc Thielen ◽  
...  

The surfaces of animals, plants and abiotic structures are not only important for organismal survival, but they have also inspired countless biomimetic and industrial applications. Additionally, the surfaces of animals and plants exhibit an unprecedented level of diversity, and animals often move on the surface of plants. Replicating these surfaces offers a number of advantages, such as preserving a surface that is likely to degrade over time, controlling for non-structural aspects of surfaces, such as compliance and chemistry, and being able to produce large areas of a small surface. In this paper, we compare three replication techniques among a number of species of plants, a technical surface and a rock. We then use two model parameters (cross-covariance function ratio and relative topography difference) to develop a unique method for quantitatively evaluating the quality of the replication. Finally, we outline future directions that can employ highly accurate surface replications, including ecological and evolutionary studies, biomechanical experiments, industrial applications and improving haptic properties of bioinspired surfaces. The recent advances associated with surface replication and imaging technology have formed a foundation on which to incorporate surface information into biological sciences and to improve industrial and biomimetic applications. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology’.


2019 ◽  
Vol 37 (No. 4) ◽  
pp. 246-251 ◽  
Author(s):  
Joanna Tkaczewska ◽  
Maciej Wielgosz ◽  
Piotr Kulawik ◽  
Marzena Zajac

The influence of drying temperature on the characteristics and gel properties of gelatine from Cyprinus carpio L. skin was studied. Gelatine was extracted from the carp skin using NaOH and ethanol pre-treatment method, extracted in water in 45°C and then dried in 4 different temperatures: 50, 70, 80°C and freeze-dried. The  electrophoresis and functional properties of gelatines were investigated. Freeze drying allowed to obtain a high gelling force, and all other methods did not give satisfactory results. The proteins in gelatines dried at higher temperatures separated by electrophoresis gave severely blurred bands. It may be explained by thermal hydrolysis of collagen fibrils. Freeze drying is the only effective method for drying this product, which can be used in industry.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 252
Author(s):  
Rongchuang Chen ◽  
Shiyang Zhang ◽  
Xianlong Liu ◽  
Fei Feng

To investigate the effect of hot working parameters on the flow behavior of 300M steel under tension, hot uniaxial tensile tests were implemented under different temperatures (950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C) and strain rates (0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1). Compared with uniaxial compression, the tensile flow stress was 29.1% higher because dynamic recrystallization softening was less sufficient in the tensile stress state. The ultimate elongation of 300M steel increased with the decrease of temperature and the increase of strain rate. To eliminate the influence of sample necking on stress-strain relationship, both the stress and the strain were calibrated using the cross-sectional area of the neck zone. A constitutive model for tensile deformation was established based on the modified Arrhenius model, in which the model parameters (n, α, Q, ln(A)) were described as a function of strain. The average deviation was 6.81 MPa (6.23%), showing good accuracy of the constitutive model.


2014 ◽  
Vol 887-888 ◽  
pp. 1032-1035 ◽  
Author(s):  
Chang Chun Di ◽  
Kai Bo Cui ◽  
Jun Qi Qin ◽  
Da Lin Wu

Aluminum brass HAL66-6-3-2 is abrasion-resistant alloy with high strength, hardness and wear resistance, corrosion resistance is also well, commonly used in the field of marine and ordnance industry. The quasi static and dynamic mechanical properties were tested through the use of electronic universal testing machine and Split Hopkinson Tension Bar (SHTB). Meanwhile, the material stress-strain curve at different temperatures and different strain rates is also obtained. Based on Johnson-Cook constitutive model, using the method of least squares fitting the experimental data to determine the model parameters, fitting and experimental results agree well.


Author(s):  
Nikolaos E. Karkalos ◽  
Angelos P. Markopoulos ◽  
Michael F. Dossis

Solution of inverse kinematics equations of robotic manipulators constitutes usually a demanding problem, which is also required to be resolved in a time-efficient way to be appropriate for actual industrial applications. During the last few decades, soft computing models such as Artificial Neural Networks (ANN) models were employed for the inverse kinematics problem and are considered nowadays as a viable alternative method to other analytical and numerical methods. In the current paper, the solution of inverse kinematics equations of a planar 3R robotic manipulator using ANN models is presented, an investigation concerning optimum values of ANN model parameters, namely input data sample size, network architecture and training algorithm is conducted and conclusions concerning models performance in these cases are drawn.


Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 35 ◽  
Author(s):  
Zhipeng Wang ◽  
Zhuzhu Niu ◽  
Quanai Hao ◽  
Lijun Ban ◽  
Haitao Li ◽  
...  

Catalytic systems consisting of copper oxide and bismuth oxide are commonly employed for the industrial production of 1,4-butynediol (BD) through ethynylation. However, few studies have investigated the influence mechanism of Bi for these Cu-based catalysts. Herein, a series of nanostructured CuO-Bi2O3 catalysts were prepared by co-precipitation followed by calcination at different temperatures. The obtained catalysts were applied to the ethynylation reaction. The textural and crystal properties of the catalysts, their reduction behavior, and the interactions between copper and bismuth species, were found to strongly depend on temperature. When calcined at 600 °C, strong interactions between Cu and Bi in the CuO phase facilitated the formation of highly dispersed active cuprous sites and stabilized the Cu+ valency, resulting in the highest BD yield. Bi2O3 was completely absent when calcined at 700 °C, having been converted into the spinel CuBi2O4 phase. Spinel Cu2+ was released gradually to form active Cu+ species over eight catalytic cycles, which continuously replenished the decreasing activity resulting from the formation of metallic Cu and enhanced catalytic stability. Moreover, the positive correlation between the in-situ-formed surface Cu+ ions and BD yield suggests that the amount of Cu+ ions is the key factor for ethynylation of formaldehyde to BD on the as prepared CuO-Bi2O3 catalysts. Based on these results and the literature, we propose an ethynylation reaction mechanism for CuO-based catalysts and provide a simple design strategy for highly efficient catalytic CuO-Bi2O3 systems, which has considerable potential for industrial applications.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yaoliang Zhu ◽  
Jin Yu ◽  
Yanyan Cai ◽  
Xin Tang ◽  
Wei Yao ◽  
...  

The deformation rules and failure types of rock fatigue damage at different temperatures are quite different, and existing constitutive theory cannot describe them quantitatively. A novel rock fatigue damage model considering the effects of temperature was presented based on phenomenology. In this model, the residual strain method was used to define the fatigue damage, and the Harris attenuation function was introduced to characterize the cyclic damage evolution. The proposed model has considered the influence of the initial damage and temperature, and the model parameters can be easily calculated. The accuracy of the model was verified by comparing the calculated values of cyclic upper strain and fatigue life with previous test results. The physical significance of the model parameters shows that parameter a is related to fatigue stress ratio and lithology, while parameter b is related to temperature. The study has some reference values for the fatigue damage model of rock considering the influence of temperature.


2005 ◽  
Vol 475-479 ◽  
pp. 1181-1184 ◽  
Author(s):  
Shi Kao Shi ◽  
Jun Min Li ◽  
Ji Zhou

Carbonate precursor of Eu3+ doped Sr2CeO4 is obtained from a mixed solution of strontium, cerium and europium nitrate using ammonium carbonate as precipitant. Calcining the carbonate precursor at different temperatures, the Eu3+ doped Sr2CeO4 phosphor is synthesized. The phase purity of the material is closely related with the calcination temperature, and the phosphor with high purity can be achieved after the precursor annealed at 1200°C. The photoluminescence performance for Eu3+ doped Sr2CeO4 depends on the concentration of Eu3+. The excitation and emission reveal efficient energy transfer from Ce4+ to Eu3+, making the emission light from blue-white to red-white, further to red as the Eu3+ concentration gradually changes from low concentration (1 mol%) to high concentration (10 mol%).


2016 ◽  
Vol 73 (4) ◽  
pp. 1741-1753 ◽  
Author(s):  
Joseph Galewsky ◽  
David Rabanus

Abstract The humidity of the free troposphere can be modeled, to first order, in terms of cold-point dehydration, followed by moistening via mixing with boundary layer air. The relative balance between these processes is of prime interest for understanding interannual variability of humidity and for understanding the water vapor feedback. Measurements of water vapor isotopic composition can provide quantitative constraints on these processes. The authors developed a stochastic model that parameterizes water vapor isotopic composition in terms of these processes and fit the model parameters to data from the Chajnantor Plateau, Chile (23°S). For August–November 2012, the average mixing ratio was 1680 ppmv, with mean water vapor δD of −234‰ and mean deuterium excess of 21‰. The data were best fit by an asymmetric last-saturation distribution with mean last-saturation mixing ratio rs of 391 (+45, −75) ppmv, a median rs of 368 (+45, −75) ppmv, and a mean mixing fraction between the freeze-dried air and moist boundary layer air of . Measurements from August to November 2014 had an average mixing ratio of 2210 ppmv, an average δD of −220‰, and an average deuterium excess of 14‰. The last-saturation distribution for this period was less skewed than for 2012, with an average rs of 520 (+42, −75) ppmv and a median rs of 507 (+25, −75) ppmv. The mean mixing fraction for 2014 was . The results show that the moistening in 2014, relative to 2012, requires increases in both the last-saturation mixing ratio and the postcondensation moistening and illustrate the utility of isotopic measurements for constraining the processes governing subtropical humidity.


2020 ◽  
Vol 20 (7) ◽  
pp. 4188-4192
Author(s):  
Shang Hao Piao ◽  
Hyeonju Lee ◽  
Jaehoon Park ◽  
Hyoung Jin Choi

We fabricate 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn) thin-film transistors (TFTs) with nanocomposite insulators. The insulator layers consist of both poly(4-vinylphenol-co-methyl methacrylate) and high-dielectric constant hafnium oxide (HfO2) nanoparticles. The HfO2 nanoparticles are ball-milled for sufficient dispersion in a nanocomposite solution to enable solution process methods to be used in preparing the insulator layers. The nanocomposite insulators demonstrate high capacitances and improve the performance of TIPS-Pn TFTs. Nonetheless, particle aggregates are produced in the nanocomposites solution with high HfO2 concentrations, generating detrimental effects on the dielectric properties and the TFT performance. Our experimental result implies that the optimum concentration of HfO2 nanoparticles in a mixed solution will find to be ~11.5 wt%.


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