Li Plating on Carbon Electrode Surface Probed by Low-Field Dynamic Nuclear Polarization 7Li NMR

Lithium deposition on graphite electrode not only reduces fast-charging capability of lithium ion batteries but also causes safety trouble. Here, a low-field 7Li dynamic nuclear polarization (DNP) is used to probe Li plating on the surfaces of three types of carbon electrodes: hard carbon, soft carbon and graphite. Owing to the strong Fermi contact interaction between 7Li and conduction electrons, the 7Li nuclear-magnetic-resonance (NMR) signal of Li metal deposited on electrode surface could be selectively enhanced by DNP. It is suggested that low-field 7Li DNP spectroscopy is a sensitive tool for investigating Li deposition on electrodes during charging/discharging processes.

NOVEL APPROACH TO EXTRACT DENSE FULL-FIELD DYNAMIC PARAMETERS OF LARGE-SCALE BRIDGES USING SPATIAL SEQUENCE VIDEO

This study proposes the use of a high-speed camera as a holographic visual sensor to obtain the dense full-field dynamic parameters of the main beam of a bridge by the field of view through uniaxial rotation photography. Based on the basic principle that the frequency and mode of a structure are inherent characteristics, the mode coordinates obtained from each field of view are unified, normalized, and matched according to the same name pixels to obtain the dense fullfield dynamic parameters of the entire bridge. The frequency and first three order modes of a self-anchored suspension test bridge are collected by the method proposed in this study. The frequency comparison between the accelerometers and dial gauges is within 3%, and the mode shapes are more holographic and more realistic than those obtained by limited measuring points. In addition, the difference in the curvature mode under various damage conditions obtained by limited measurement points is compared with that obtained by the method proposed in this study. Results shows that the dense full-field modal curvature difference can reflect the change in the damage location even in a low order, which means the sensitivity of the change of damage location in low-order modal.

Factors Influencing Curriculum Leadership of Primary and Secondary School Teachers from the Perspective of Field Dynamic Theory: An Empirical Investigation in China

Teacher curriculum leadership is in urgent demand to promote the sustainable advancement of curriculum reform, and an important guarantee for the sustainable development of students. It is of important theoretical and practical significance to clarify the influencing factors of the use and the development of teachers’ curriculum leadership. Based on Lewin’s field dynamic theory, this study conducts a multiple linear regression analysis on the data of 19,521 primary and secondary school teachers in 20 provinces of China, and investigates the influencing factors of teacher curriculum leadership from individual and school fields. The results show that individual field factors are the driving force for teachers to exert and develop curriculum leadership. When teachers have internal leading motivation, the school environment becomes an important inducing force. This finding confirms the realistic rationality of the field dynamic theory, and provides a clear direction for formulating relevant policies and practical plans for enhancing teacher curriculum leadership. That is, it is necessary to fully stimulate the internal motivation of teachers for curriculum leadership, but also to create a school environment for teachers to exercise and develop curriculum leadership.

Dynamic Reservoir Analysis of Corrib Field Surveillance Data Through the Use of Advanced Deconvolution Techniques

This paper presents an analysis of the Corrib field surveillance dynamic pressure and rate data. The Corrib field, on production since December 2015, is a gas reservoir developed with six wells. The field static gas initially in place (GIIP) is around 1.2 Tcf of dry gas and the reservoir is comprised of a complex heterogeneous sandstone consisting of a high net to gross sequence of low sinuosity braided fluvial channel, sheet sand, playa and sandflat facies of varying reservoir quality (from single to hundreds of millidarcys) with an abundance of mapped faults. The dynamic reservoir analysis approach used in this study is based on a form of pressure-rate deconvolution that has been presented in an earlier paper SPE-195441 for the Tamar field, Israel. The pressure transient analysis (PTA) software that implements this analysis capability handles both singlewell and multi-well analysis problems. From a preliminary review of Corrib field dynamic behavior, it was concluded that this field data can be analyzed using single-well pressure-rate deconvolution applied to the data of each reservoir well separately. This contrasts with the Tamar field that required a true multiwell deconvolution analysis approach. Different approaches in these cases are dictated by the differences in reservoir architecture, geology, offtake strategy and the character of connectivity across these two fields. There are several pressure-rate deconvolution algorithms implemented in different PTA software tools used in the industry. All these algorithms implement a form of automatic regression and are sensitive to the quality of pressure and rate data that serve as input into the deconvolution algorithm. These automatic algorithms are often not robust enough to be used with surveillance type data acquired during long term production operations. The deconvolution approach used in this work is not automatic and, as a result, the deconvolution results are not as sensitive to the data quality. Rather, it relies on specialized software that facilitates manual reconstruction of constant rate drawdown responses. This human approach in combination with specialized software allows an engineer not to just reconstruct a drawdown response but to "explore" the pressure and rate data to develop significant insights of the dynamic reservoir behavior. This deeper understanding is an additional advantage over automated techniques and is the purpose of reservoir analysis. The Corrib field analysis discussed in this paper is a demonstration of what can be achieved using this combination of human intelligence and specialized software tools. Demonstration of the workflow used for manual reconstruction of deconvolved response functions and the role of the specialized software used that implements this workflow is explained. In the course of this reconstruction, an "exploration" process of trying to reconstruct the transient pressure behavior reflected in the data is engaged/utilized. Once reconstructed, this response is interpreted in terms of reservoir and well properties. The end result of this investigation is a deep understanding of the Corrib gas field dynamic behavior not easily obtained from conventional PTA methods. For example, it shows that early production data clearly exhibit signs of interference between wells. However, once the field production drops off the plateau period and the well production starts to decline, the six producing wells dynamically divide the reservoir into separate drainage areas and the well interference in a way "disappears" - the wells behave as if each of them produces from its own drainage compartment. This allows pressure rate deconvolution on a single-well basis, based on each compartment instead of using multi-well deconvolution on the field as a whole. The pore volume of each such compartment is reflected in the late time pressure behavior of the respective drawdown response associated with the well data. The sum of these individual pore volumes per well in the field yields the total pore volume connected to the wells that is supported by the reservoir dynamic behavior. These insights are reinforced by the use of synthetic models to provide clarity and understanding of the drainage compartment theory used during Corrib analysis.

Social Control of Intellect: Four Features of the Academic–Media Nexus

Intellect in social theory is often presented as an ideal type—the critical, iconoclastic side of the mind—but it must anticipate an audience in mediated contexts, unlike in the Kantian realm of transcendent reason. The terrain in which academia and media meet, consequently, is ripe for exploration into the fate of intellect when transgressive. This article explicates four features of the academic–media nexus that contribute to social control of intellect: instrumental rationalism of faculty, strategic management of university communication, journalistic appropriation of the “public intellectual” role, and surveillance of academic discourse. The article situates the features in a framework to recognize whether they originate primarily in academia or media, and whether the controlling process occurs through internalized norms or calculated practice. While social control is understood as recursive and reinforcing, reflexivity induced in an inter-field dynamic implies the possibility of reconciling intellect with news work.

Stereo PIV measurements of oscillatory plasma forcing in the cross-plane of a channel flow

The present work describes an experimental investigation that applies stereo particle image velocimetry in a cross-plane of a turbulent channel flow that is additionally perturbed by spanwise oscillatory body forces, induced by a plasma actuator and designed to mimic the effect of spanwise wall oscillations. The experiment is aimed at retrieving the forcing-correlated scales and the turbulent flow stochastic fluctuations for the measured cross-plane. The first are macroscopic scales and require a larger investigation domain while the latter benefit of a higher resolution. Furthermore, the extended flow-field dynamic range posed a challenge on the experiment design, finally leading to an optimal tradeoff. The results of the unactuated flow compare well to the direct numerical simulations of Hoyas and Jimenez ́ (2008), while the actuated case demonstrates strong near-wall momentum addition and spanwise modulation of the streamwise flow component.