Crack detection in lithium-ion cells using machine learning

It is an open question how the particle microstructure of a lithium-ion electrode influences a potential thermal runaway. In order to investigate this, information on the structural changes, in particular cracked particles, caused by the failure are desirable. For a reliable analysis of these changes a reasonably large amount of data is necessary, which necessitates automatic extraction of particle cracks from tomographic 3D image data. In this paper, a classification model is proposed which is able to decide whether a pair of particles is the result of breakage, of the image segmentation, or neither. The classifier is developed using simulated data based on a 3D stochastic particle model. Its validity is tested by applying the methodology to hand-labelled data from a real electrode. For this dataset, an overall accuracy of 73% is achieved

Characteristics of Sexual Abuse in Childhood and Adolescence Influence Sexual Risk Behavior in Adulthood

Childhood and adolescent sexual abuse has been associated with subsequent (adult) sexual risk behavior, but the effects of force and type of sexual abuse on sexual behavior outcomes have been less well-studied. The present study investigated the associations between sexual abuse characteristics and later sexual risk behavior, and explored whether gender of the child/adolescent moderated these relations. Patients attending an STD clinic completed a computerized survey that assessed history of sexual abuse as well as lifetime and current sexual behavior. Participants were considered sexually abused if they reported a sexual experience (1) before age 13 with someone 5 or more years older, (2) between the ages of 13 and 16 with someone 10 or more years older, or (3) before the age of 17 involving force or coercion. Participants who were sexually abused were further categorized based on two abuse characteristics, namely, use of penetration and force. Analyses included 1177 participants (n=534 women; n=643 men). Those who reported sexual abuse involving penetration and/or force reported more adult sexual risk behavior, including the number of lifetime partners and number of previous STD diagnoses, than those who were not sexually abused and those who were abused without force or penetration. There were no significant differences in sexual risk behavior between nonabused participants and those who reported sexual abuse without force and without penetration. Gender of the child/adolescent moderated the association between sexual abuse characteristics and adult sexual risk behavior; for men, sexual abuse with force and penetration was associated with the greatest number of episodes of sex trading, whereas for women, those who were abused with penetration, regardless of whether the abuse involved force, reported the most episodes of sex trading. These findings indicate that more severe sexual abuse is associated with riskier adult sexual behavior

The quality of translated medical research questionnaires

Little data have been published on the subject of medical research and translation. This study endeavours to contribute to such literature by investigating the quality of original and retranslated medical questionnaires. The various steps researchers follow when translating their questionnaires or other texts are considered, while the different translation approaches and their impact on the quality of medical research are briefly discussed. These are the linguistic, text-linguistic and functionalist approaches. The design, translation approach and quality of the original translations are explained, along with the development of the retranslation questionnaires. Since the functionalist approach does not essentially follow equivalent word-for-word translations, back translation was omitted in the retranslation. One of the main functions of functionalism or Skopos (Greek for purpose, aim or intention) is to translate with the target audience in mind. By following this functionalist approach when translating medical questionnaires, the translator can ensure that the communication is successful. At the same time, the collection of valid data in medical research is ensured, improving the quality of these data. It is recommended that trained translators, who are familiar with the subject matter, do the translations. Copyright © 2005 NISC Pty Ltd.Articl

Improving contact prediction along three dimensions

Correlation patterns in multiple sequence alignments of homologous proteins can be exploited to infer information on the three-dimensional structure of their members. The typical pipeline to address this task, which we in this paper refer to as the three dimensions of contact prediction, is to (i) filter and align the raw sequence data representing the evolutionarily related proteins; (ii) choose a predictive model to describe a sequence alignment; (iii) infer the model parameters and interpret them in terms of structural properties, such as an accurate contact map. We show here that all three dimensions are important for overall prediction success. In particular, we show that it is possible to improve significantly along the second dimension by going beyond the pair-wise Potts models from statistical physics, which have hitherto been the focus of the field. These (simple) extensions are motivated by multiple sequence alignments often containing long stretches of gaps which, as a data feature, would be rather untypical for independent samples drawn from a Potts model. Using a large test set of proteins we show that the combined improvements along the three dimensions are as large as any reported to dat

Improving Contact Prediction along Three Dimensions

Correlation patterns in multiple sequence alignments of homologous proteins can be exploited to infer information on the three-dimensional structure of their members. The typical pipeline to address this task, which we in this paper refer to as the three dimensions of contact prediction, is to (i) filter and align the raw sequence data representing the evolutionarily related proteins; (ii) choose a predictive model to describe a sequence alignment; (iii) infer the model parameters and interpret them in terms of structural properties, such as an accurate contact map. We show here that all three dimensions are important for overall prediction success. In particular, we show that it is possible to improve significantly along the second dimension by going beyond the pair-wise Potts models from statistical physics, which have hitherto been the focus of the field. These (simple) extensions are motivated by multiple sequence alignments often containing long stretches of gaps which, as a data feature, would be ratheruntypical for independent samples drawn from a Potts model. Using a large test set of proteins we show that the combined improvements along the three dimensions are as large as any reported to date.Peer reviewe

Investigation of the Combustion Process of Boron Particle Containing Solid Fuel Slabs in a Rearward Facing Step Combustor

In order to get a better insight in solid fuel ramjet combustion processes the combustion behavior of solid fuel slabs with and without boron particle addition had been investigated in a planar step combustor under ramjet relevant conditions concerning the air inlet temperature. Various intrusive and non-intrusive diagnostic techniques had been used to analyze the highly turbulent multiphase combustion process. Large scale vortical structures can be seen in the outer zone above the diffusion flame in the developing boundary layer behind the recirculation zone with Colour Schlieren as well as with PIV. Distributions of the gas phase temperature, velocities of reacting particles as well as concentrations of stable reaction products have been determined and are presented here, too

Stochastic 3D modeling of the microstructure of lithium ion battery anodes via Gaussian random fields on the sphere

The performance and durability of lithium ion batteries are highly dependent on the microstructures of their components. Recently, methods have been developed that make possible the simulation of electrochemical processes on 3D representations of lithium ion batteries. However, it is difficult to obtain realistic microstructures on which these simulations can be carried out. In this paper, we develop a stochastic model that is able to produce realistic microstructures of lithium ion battery anodes, which can serve as input for the simulations. We introduce the use of Gaussian random fields on the sphere as models for the particles that form the anodes. Using this new approach, we are able to model realistic particle geometries. The stochastic model also uses a number of techniques from stochastic geometry and spatial statistics. We carry out validation of our model, in order to demonstrate that it realistically describes the key features of the anode s microstructur

Stochastic microstructure modeling and electrochemical simulation of lithium ion cell anodes in 3D

Thermodynamically consistent transport theory is used to compare 3D images of real anode microstructures from lithium ion batteries to virtual ones created by a parametric stochastic 3D microstructure model. Half cell simulations with di erent applied currents show that for low currents the deviations between various electrochemical quantities like current density or overpotential are negligibly small. For larger currents small di erences become more pronounced. Qualitative and quantitative di erences of these features are discussed with respect to the microstructure and it is shown that the real and virtual structures behave similar during electrochemical simulations. Extensions of the stochastic microstructure model, which overcome small di erences in electrochemical behavior, are proposed. Keywords 3D microstructure modeling, lithium ion battery, thermodynamically consistent transport theory, virtual materials testing, model validatio