Study of the pyroelectric behavior of BaTi<Subscript>1−<Emphasis Type="BoldItalic">x</Emphasis></Subscript>Sn<Subscript><Emphasis Type="BoldItalic">x</Emphasis></Subscript>O<Subscript>3</Subscript> piezo-ceramics

In this work, the thermal square wave method at single-frequency (TSWM) was applied to functionally graded BaTi_1−x Sn _x O₃ samples with a tin gradient of 0.075 ≤ x ≤ 0.15. The samples were fabricated by sintering of bi-, tri- and tetramorph green bodies. The polarization at the back side with a higher tin content was in opposite direction to the polarization of the surface with a lower tin content. This was attributed to the appearance of a space charge layer. The determined depth profiles of the pyroelectric coefficient illustrate the appearance of a nearly constant polarization in the region of lower tin concentration of tri- and tetramorph samples. The pyroelectric coefficient profiles were in good agreement with the averaged over sample thickness pyroelectric coefficient obtained separately by the quasistatic method.     

Influence of Clod-Size and Structure on Wetting-Induced Volume Change of Compacted Soil

Volume changes due to wetting may occur in naturally deposited soils as well as earthen construction (e.g., compacted fills or embankments). Depending on the stress level, some soils exhibit increase in volume upon wetting (swell) while others may exhibit decrease in volume upon wetting (collapse). The work described in this paper focused on wetting-induced volume changes in compacted soils. Motivation for this work stemmed from observations of earthen structures that exhibit problematic behavior under wetting conditions, even though soils were compacted to engineering specifications (i.e., at or above minimum density and within moisture content ranges). Not only is this problematic behavior a concern but also the laboratory tests used to predict settlement of constructed facilities may not properly model the actual behavior of soil compacted under field conditions. For example, settlements experienced by compacted fills may be different from settlement predictions based on one-dimensional oedometer tests. These differences are partly related to the variations in the soil structure in tested specimens that arise because soil clods compacted in the laboratory are smaller than soil clods compacted in the field. The term “soil structure” includes the combined effects of soil fabric and interparticle forces. “Fabric” generally refers to the geometric arrangement of particles, whereas interparticle forces include physical and physicochemical interactions between particles. The soil structure in this case is associated with specimen preparation methods and is influenced by several factors including soil composition (including pore water chemistry), compaction method, clod sizes, initial moisture condition of clods, dry density or void ratio, and compaction moisture content. A laboratory research study was conducted to investigate the influence of variations in clod-size and structure on one-dimensional volume change, with emphasis on wetting-induced volume change, for nine different fine-grained soils. The results of the study suggest that the influence of structure in one-dimensional oedometer tests depends on soil type and nature of the clods in the compacted soil. Clayey soils appear to be influenced more by differences in structure, whereas silts or clayey sands of low plasticity (PI<10) do not appear to suffer as much from structure effects in one-dimensional oedometer tests. This is attributed to more extensive clod development in clayey soils. Furthermore, the moisture condition of clods appears to have an important influence on volume change behavior.     

Performance characteristics of Ultralife's solid polymer rechargeable batteries

Ultralife Batteries delivered the world's first commercial shipments of solid polymer rechargeable batteries in 1997. The battery consists of a Li_xMn₂O₄⁻ based cathode, graphite anode and proprietary polymeric separator. Energy density of the batteries exceeds 120 W h kg⁻¹ and 200 W h dm⁻³ at the C rate. Pulse capability up to 5 C has been demonstrated. More than 90% of the initial C rate capacity remains after 500 continuous cycles at room temperature. These solid polymer rechargeable batteries also show good low and high temperature performance and have good safety characteristics.     

Test adequacy criteria for UML design models

Systematic design testing, in which executable models of behaviours are tested using inputs that exercise scenarios, can help reveal flaws in designs before they are implemented in code. In this paper a technique for testing executable forms of UML (Unified Modelling Language) models is described and test adequacy criteria based on UML model elements are proposed. The criteria can be used to define test objectives for UML designs. The UML design test criteria are based on the same premise underlying code test criteria: coverage of relevant building blocks of models is highly likely to uncover faults. The test adequacy criteria proposed in this paper are based on building blocks for UML class and interaction diagrams. Class diagram criteria are used to determine the object configurations on which tests are run, while interaction diagram criteria are used to determine the sequences of messages that should be tested. Copyright © 2003 John Wiley & Sons, Ltd.     

The PagKNAT2/6b-PagBOP1/2a Regulatory Module Controls Leaf Morphogenesis in Populus

Leaf morphogenesis requires precise regulation of gene expression to achieve organ separation and flat-leaf form. The poplar KNOTTED-like homeobox gene PagKNAT2/6b could change plant architecture, especially leaf shape, in response to drought stress. However, its regulatory mechanism in leaf development remains unclear. In this work, gene expression analyses of PagKNAT2/6b suggested that PagKNAT2/6b was highly expressed during leaf development. Moreover, the leaf shape changes along the adaxial-abaxial, medial-lateral, and proximal-distal axes caused by the mis-expression of PagKNAT2/6b demonstrated that its overexpression (PagKNAT2/6b OE) and SRDX dominant repression (PagKNAT2/6b SRDX) poplars had an impact on the leaf axial development. The crinkle leaf of PagKNAT2/6b OE was consistent with the differential expression gene PagBOP1/2a (BLADE-ON-PETIOLE), which was the critical gene for regulating leaf development. Further study showed that PagBOP1/2a was directly activated by PagKNAT2/6b through a novel cis-acting element “CTCTT”. Together, the PagKNAT2/6b-PagBOP1/2a module regulates poplar leaf morphology by affecting axial development, which provides insights aimed at leaf shape modification for further improving the drought tolerance of woody plants.     

间隔机织物的卷绕、切割和存储系统

描述了间隔机织物的新型卷绕、切割和存储系统的设计.这种系统的关键问题是间隔织物包含织物结构如间隔,即所谓的交联.为了防止玻璃纤维-聚丙烯混纺纱线中玻璃纤维被破坏,必须避免交联塌陷.这种织物被用作热塑性纺织增强复合材料模件的预型件.     

Lorentzian-Corrected Apparent Exchange-Dependent Relaxation (LAREX) Ω-Plot Analysis—An Adaptation for qCEST in a Multi-Pool System: Comprehensive In Silico,In Situ,and In Vivo Studies

Based on in silico, in situ, and in vivo studies, this study aims to develop a new method for the quantitative chemical exchange saturation transfer (qCEST) technique considering multi-pool systems. To this end, we extended the state-of-the-art apparent exchange-dependent relaxation (AREX) method with a Lorentzian correction (LAREX). We then validated this new method with in situ and in vivo experiments on human intervertebral discs (IVDs) using the Kendall-Tau correlation coefficient. In the in silico experiments, we observed significant deviations of the AREX method as a function of the underlying exchange rate (k_ba) and fractional concentration (f_b) compared to the ground truth due to the influence of other exchange pools. In comparison to AREX, the LAREX-based Ω-plot approach yielded a substantial improvement. In the subsequent in situ and in vivo experiments on human IVDs, no correlation to the histological reference standard or Pfirrmann classification could be found for the f_b (in situ: τ = −0.17 p = 0.51; in vivo: τ = 0.13 p = 0.30) and k_ba (in situ: τ = 0.042 p = 0.87; in vivo: τ = −0.26 p = 0.04) of Glycosaminoglycan (GAG) with AREX. In contrast, the influence of interfering pools could be corrected by LAREX, and a moderate to strong correlation was observed for the fractional concentration of GAG for both in situ (τ = −0.71 p = 0.005) and in vivo (τ = −0.49 p < 0.001) experiments. The study presented here is the first to introduce a new qCEST method that enables qCEST imaging in systems with multiple proton pools.     

Review of the Fusion Materials Research Program

This report presents the results and recommendations of the deliberations of the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee Panel on the Review of the Fusion Materials Research Program carried out during 1998. Metrics evaluated included evidence of recognition, publications per worker, new people attracted to the work and significance of recent accomplishments.     

A systematic mapping study on best practices for domain-specific modeling

Model-driven software development comes in different styles. While standard-based approaches leverage existing language standards (e.g., UML), tooling, and development processes, domain-specific modeling (DSM) requires languages and tool support to be created prior to the actual software development. The design, implementation, and testing of languages and tool support require a wide spectrum of methods and techniques which introduce complexity and new challenges. To tackle these DSM-specific challenges, best practices have been collected from various application domains and published in literature to guide the development and application of DSM solutions. It is the goal of this paper to identify studies reporting best practices on domain-specific modeling. Moreover, a systematic and comprehensive compilation of best practices should act as a starting point to identify literature that facilitates industrial adoption of DSM. To search for literature and classify identified studies, we conduct a systematic mapping study (SMS). Furthermore, we perform an in-depth analysis of the identified studies to answer how practices overlap, complement, or contradict each other. The systematic search resulted in 21 studies reporting 321 best practices. From these 321 practices, we compiled 192 unique best practices. We found that the DSM community created a substantial corpus of best practices for DSM. The large majority of practices (75%) are only reported once. The top best practices by number of reports contain only practices that are reported at least four times. However, the frequency of reports does not necessarily imply a high importance of practice, as the application of practices is always context specific.