Relativity and the lead-acid battery

The energies of the solid reactants in the lead-acid battery are calculated ab initio using two different basis sets at non-relativistic, scalar relativistic, and fully relativistic levels, and using several exchange-correlation potentials. The average calculated standard voltage is 2.13 V, compared with the experimental value of 2.11 V. All calculations agree in that 1.7-1.8 V of this standard voltage arise from relativistic effects, mainly from PbO2 but also from PbSO4

Process intensification through integration of upstream perfusion cell culture with downstream continuous chromatography in monoclonal antibody production

Process intensification is gaining interest as a strategy to reduce production costs, while improving product quality and throughput in the manufacturing of biopharmaceuticals. For a competitive production process, continuous or semi-continuous upstream and downstream processing can be employed. Compared with a process performed in batch runs, continuous processing allows for increased capacity utilization and eliminates or minimized the need for intermediate hold-up steps. Here, we describe the integration of a high-performing upstream cell culture process with downstream purification utilizing new emerging technologies such as periodic counter-current (PCC) chromatography and straight-through processing (STP). A high-cell density perfusion process based on commercially available ActiCHO™ cell culture media was developed for a MAb-producing Chinese hamster ovary (CHO) cell line. Medium prototypes were evaluated in small scale using the single-use ReadyToProcess WAVE™ 25 bioreactor system. Medium optimization resulted in a final process with a cell-specific perfusion rate (CSPR) of less than 50 pL/cell/d. Process performance was verified at laboratory scale using single-use stirred-tank bioreactor systems. Productivity and product quality of the developed perfusion process were compared with a standard fed-batch process. MAb capture on MabSelect SuRe™ LX protein A chromatography medium (resin) was performed in a three-column PCC (3C PCC) setup. The capture step was followed by two polishing steps using Capto™ S ImpAct ion exchange and Capto adhere multimodal ion exchange media in serially connected columns in a STP setup. MAb purity and yield of the developed continuous processes were compared with traditional setups performed in batch runs. In this case study, we demonstrate the feasibility of integrated upstream and downstream MAb processing performed in a continuous manner. The developed process shows a performance equivalent to traditional processing performed in batch runs

EduCOR: An Educational and Career-Oriented Recommendation Ontology

With the increased dependence on online learning platforms and educational resource repositories, a unified representation of digital learning resources becomes essential to support a dynamic and multi-source learning experience. We introduce the EduCOR ontology, an educational, career-oriented ontology that provides a foundation for representing online learning resources for personalised learning systems. The ontology is designed to enable learning material repositories to offer learning path recommendations, which correspond to the user’s learning goals and preferences, academic and psychological parameters, and labour-market skills. We present the multiple patterns that compose the EduCOR ontology, highlighting its cross-domain applicability and integrability with other ontologies. A demonstration of the proposed ontology on the real-life learning platform eDoer is discussed as a use case. We evaluate the EduCOR ontology using both gold standard and task-based approaches. The comparison of EduCOR to three gold schemata, and its application in two use-cases, shows its coverage and adaptability to multiple OER repositories, which allows generating user-centric and labour-market oriented recommendations. Resource: https://tibonto.github.io/educor/

Local structure of liquid Ge(1)Sb(2)Te(4) for rewritable data storage use

Conference Name:11th International Conference on Magnetic Fluids. Conference Address: Kosice, SLOVAKIA. Time:JUL 23-27, 2007.Phase-change materials based on chalcogenide alloys have been widely used for optical data storage and are promising materials for nonvolatile electrical memory use. However, the mechanism behind the utilization is unclear as yet. Since the rewritable data storage involved an extremely fast laser melt-quenched process for chalcogenide alloys, the liquid structure of which is one key to investigating the mechanism of the fast reversible phase transition and hence rewritable data storage, here by means of ab initio molecular dynamics we have studied the local structure of liquid Ge(1)Sb(2)Te(4). The results show that the liquid structure gives a picture of most Sb atoms being octahedrally coordinated, and the coexistence of tetrahedral and fivefold coordination at octahedral sites for Ge atoms, while Te atoms are essentially fourfold and threefold coordinated at octahedral sites, as characterized by partial pair correlation functions and bond angle distributions. The local structure of liquid Ge(1)Sb(2)Te(4) generally resembles that of the crystalline form, except for the much lower coordination number. It may be this unique liquid structure that results in the fast and reversible phase transition between crystalline and amorphous states

Formation of Large Voids in the Amorphous Phase-Change Memory Ge2Sb2Te5 Alloy

Natural Science Foundation of Fujian Province of China [2008J0166]; Xiamen UniversityOn the basis of ab initio molecular dynamics simulations, large voids mainly surrounded by Te atoms are observed in molten and amorphous Ge2Sb2Te5, which is due to the clustering of two- and threefold coordinated Te atoms. Furthermore, pressure shows a significant effect on the clustering of the under coordinated Te atoms and hence the formation of large voids. The present results demonstrate that both vacancies and Te play an important role in the fast reversible phase transition process

Fast crystallization of chalcogenide glass for rewritable memories

Natural Science Foundation of Fujian Province of China [2008J0166]; Xiamen University [X071I4]By ab initio molecular dynamics simulations, we unraveled the unique network structure of amorphous Ge(1)Sb(2)Te(4), which shows high rank of ordering and mostly consists of distorted defective octahedrons with a small portion of distorted tetrahedrons. The phase transition from amorphous to cubic Ge(1)Sb(2)Te(4) would be mainly a process of angle rearrangements of tetrahedrons to octahedrons and vice versa. (C) 2008 American Institute of Physics

Stable nitride complex and molecular nitrogen in N doped amorphous Ge2Sb2Te5

Nature Science Foundation of Fujian Province of China [2008J0166]; Xiamen University [X071I4]Nitrogen doping is identified to be a sufficient way to reduce the power consumption of Ge2Sb2Te5, a phase-change material for data storage. On the basis of ab initio molecular dynamics simulations, we show that the doped N in amorphous Ge2Sb2Te5 coexist as Ge(Sb, Te)N complex and N-2, and high density of the film produces more N-2. Furthermore, both Ge(Sb, Te)N complex and N-2 are stable upon annealing at 600 K