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41.
Leon Cohen Elsa Sanchez Mariluz Martin Fernando Soto Francisco Trujillo 《Journal of surfactants and detergents》2016,19(5):1089-1092
The effects of both linear alkylbenzene sulfonate (LAS) and zein protein concentrations on protein solubilization were investigated to better understand the influence of increasing concentration of the surfactant on protein denaturation and skin irritation. Different methods have been used for the determination of the amount of protein dissolved. A wide range of LAS concentrations and zein amounts were used. The results confirm that protein solubilization increases with LAS concentration increase and demonstrate that a minimum LAS/Zein ratio exists for all the zein to be dissolved. 相似文献
42.
An investigation was carried out in a circulating fluidized bed to explore if rice husk could be fluidized without mixing it with any foreign solids. Experimental results indicate that bed cross‐section has an important influence on the fluidization characteristics of rice husk. Larger the cross‐section, easier it is to fluidize the husk without slugging. Particle size, sphericity, bulk density, and transport velocity of husk were measured. The riser was operated under bubbling bed regimes. Efforts were made to measure the minimum fluidization velocity by varying the bed depth and cross‐section. 相似文献
43.
Hendrikus A. Visser Ton C. Bor Mannes Wolters Tom A. P. Engels Leon E. Govaert 《大分子材料与工程》2010,295(7):637-651
The most widespread application of polymers in structural applications is their use as pipe material for e.g., gas distribution systems. Pipes have a design lifetime of typically 50 years, which rules out real‐time lifetime assessment methods. Here, an engineering approach is presented, which makes it possible to predict long‐term ductile failure of loaded glassy polymers based on short‐term tests. The approach is based upon the hypothesis that failure is governed by accumulation of plastic deformation up to a critical strain. A pressure‐modified Eyring relation is employed to calculate the accumulation of plastic strain for any simple loading geometry. It is demonstrated that the approach can produce accurate quantitative time‐to‐failure predictions for loaded PC specimens and uPVC pipe segments.
44.
Leon Cohen 《北京理工大学学报(英文版)》2021,30(3):228-237
A simple and mathematically tractable model of a nonstationary process is developed.The process is the sum of waves where the parameters of the waves are random. Explicit expressions for the mean and autocorrelation function at each position as a function of time are obtained.In the case of infinite time, the model evolves into a stationary process. The time-frequency distribution at each position is also obtained. An explicit example is given where the initial waves are Gaussian. The case where there is dispersion in the propagation is also discussed. 相似文献
45.
Leon O. Chua Chwen-Cher Chang 《International Journal of Circuit Theory and Applications》1987,15(2):143-170
A new simple circuit model for the MOS (metal-oxide-semiconductor) structure is presented. the model consists of three elements, namely, a linear capacitor, a non-linear capacitor and a C-dynamic element. Each component bears a simple relationship to the physical operating mechanism inside the MOS structure. the model can be used for simulating arbitrary MOS structure circuits under all operating conditions. In particular, it is capable of reproducing the structure's frequency-dependent small-signal characteristics. the model is also shown to exhibit many important and interesting dynamic behaviours under forward, reverse and sinusoidal operating modes. The model is based mainly upon the device's physical operating principles. But perhaps the most significant implication of this model is that it is the first ever to use a dynamic element to model the MOS structure from a physical approach. 相似文献
46.
Dr.‐Ing. Andrea Ohle Michael Obst Prof. Dr.‐Ing. Norbert Mollekopf Prof. Dr.‐Ing. Leon Urbas 《化学,工程师,技术》2014,86(5):640-648
Modularization has been identified as one of the research fields of the ?50 % idea”?. A development methodology for modules must consider both the economies of scale for investment costs and costs of operation and maintenance. In this paper, the impact of an absorber module, which is offered as discretized diameter scaling, on the total process is investigated at the example of the CO2 separation from biogas. The simulation shows the effect of this approach to the stripper diameter and the energy demand of the process. The calculations form the basis for applying cost models. 相似文献
47.
Leon Wehrhan Prof. Dr. Alexander Hillisch Dr. Stefan Mundt Dr. Adrian Tersteegen Dr. Katharina Meier 《ChemMedChem》2020,15(21):2010-2018
Target druggability assessment is an integral part of the early target characterization and selection process in pharmaceutical industry. Here, we investigate a set of five different serine proteases from the blood coagulation cascade. The aim of this study is twofold. Firstly, leveraging the wealth of available in-house high-throughput screening (HTS) data, we analyze HTS hit rates and discuss their predictive value for the development of small molecule (SMOL) candidates. Purely structure-activity relationship (SAR) based druggability ratings are compared with computational protein-structure based druggability assessments. Secondly, we evaluate the impact of using conformational ensembles from molecular dynamics (MD) simulations instead of single static crystal structures as basis for computational druggability assessments. Based on this study, we recommend incorporating molecular dynamics routinely into the early target characterization process, especially if only a single X-ray structure is available. 相似文献
48.
Prof. Dr.-Ing. Michael Bortz Dr.-Ing. Kai Dadhe Prof. Dr.-Ing. Sebastian Engell Dr.-Ing. Vanessa Gepert Prof. Dr.-Ing. Norbert Kockmann Dr. rer nat Ralph Müller-Pfefferkorn Dr.-Ing. Thorsten Schindler Prof. Dr.-Ing. Leon Urbas 《化学,工程师,技术》2023,95(7):975-988
The chemical industry is one of the key industrial sectors in Germany and at the same time one of the largest consumers of energy and raw materials. A successful energy transition and the development of a circular economy can only succeed if they are actively supported and shaped by the chemical industry – through the redesign of existing production processes and the exploration and implementation of new process routes. The challenge is to realize this transformation within a very short time and for many production processes, whereby a much larger number of process routes must be explored. Digital technologies are key to master this transformation towards more sustainability, climate, and environmental protection. The KEEN project aims to explore and leverage artificial intelligence (AI) opportunities in process industry. The newly developed AI methods are tested wherever possible in real working environments and production plants to prove the economic benefit, applicability, and reliability of the methods and technologies. 相似文献
49.
Mechanical activation before carbothermic reduction can substantially enhance the formation of SiC from SiO2 and carbon mixtures. However, the morphology (e.g., particles or whiskers) of SiC formed from mechanically activated SiO2 and carbon mixtures is dependent of the degree of mechanical activation and the condition of the subsequent carbothermic reduction. These phenomena are investigated and rationalized based on the increased reactivity of the reactants and SiC formation mechanisms. 相似文献
50.
An experimental procedure was developed to study directly the process by which liquid bridges between small particles in a granule form and solidify. The evolution of saturated solutions of such pharmaceutical excipients as lactose and mannitol in a liquid bridge was studied on a system situated on a microscope slide. Solidification and crystallization kinetics and phase composition during and immediately following bridge formation were observed directly. It was shown that bridges on the microscope slide and in the granule behave very much the same regardless of the different length and diffusion-scales of the two systems.We found that solid bridge formation takes place in several consecutive but distinct steps. In the case of lactose, considerable shrinkage of the initial liquid bridge takes place prior to the onset of crystallization. Further bridge solidification at ambient conditions occurs via simultaneous crystallization and vitrification within minutes. As a result, a “solid” bridge usually contains both a crystalline and a non-crystalline phase, the crystalline phase being predominately α-lactose monohydrate. Most of the non-crystalline phase eventually converts to crystalline β-lactose but the process may take many hours or even days. Results for this process are compared for samples obtained from different manufacturers of commercially available lactose. In the case of mannitol, different polymorphic forms crystallize as the drying/crystallization process progresses. A formed “solid” bridge usually contains several polymorphs of mannitol. The relevance of the behavior of the two model systems (pure lactose and pure mannitol) to a real granulation and tabletting process is discussed. 相似文献