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111.
Asymmetrically cracked specimens fail with considerably less ductility than symmetrically cracked ones, due to the crack progressing along a shear band into pre-damaged material. A formulation for the accumulation of damage ahead of an asymmetric crack is presented, based on strain increments following a power law relation. These results are integrated both numerically and approximately.The crack growth per unit displacement increases approximately as the logarithm of the total crack advance per inclusion spacing , and varies inversely as the critical fracture strain c. This provides a basis for predicting large-scale, fully plastic fracture from asymmetric weld defects, using small-scale laboratory specimens.
Résumé Les éprouvettes fissurées de manière asymétrique se rompent avec beaucoup moins de ductilité que celles qui sont fissurées de manières symétrique, en raison du fait que la fissure se développe suivant une bande de cisaillement dans un matériau préendommagé. On Présente une formulation de l'accumulation du dommage en avant d'une fissure asymétrique, en se basant sur des gradients de déformations répartis selon une loi quadratique. L'interprétation des résultats est effectuée par voie numérique et par approximation.On constate que le croissance d'une fissure par unité de déplacement est sensiblement proportionnelle au logarithme de l'avancement total de la fissure rapporté à l'espacement entre deux inclusions , et en raison inverse de la déformation critique à la rupture c. Ceci fournt une base pour prédire une rupture à plus grande échelle et en conditions tout à fait plastiques, qui résulteront de défauts de soudage asymétriques, et ce en utilisant des éprouvettes réduites de laboratoire.相似文献
112.
James I. Mitchell-White Thomas Stockner Nicholas Holliday Stephen J. Briddon Ian D. Kerr 《International journal of molecular sciences》2021,22(6)
The five members of the mammalian G subfamily of ATP-binding cassette transporters differ greatly in their substrate specificity. Four members of the subfamily are important in lipid transport and the wide substrate specificity of one of the members, ABCG2, is of significance due to its role in multidrug resistance. To explore the origin of substrate selectivity in members 1, 2, 4, 5 and 8 of this subfamily, we have analysed the differences in conservation between members in a multiple sequence alignment of ABCG sequences from mammals. Mapping sets of residues with similar patterns of conservation onto the resolved 3D structure of ABCG2 reveals possible explanations for differences in function, via a connected network of residues from the cytoplasmic to transmembrane domains. In ABCG2, this network of residues may confer extra conformational flexibility, enabling it to transport a wider array of substrates. 相似文献
113.
Operational optimization of a building-level
integrated energy system considering
additional potential benefits of energy
storage
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Sai Liu Cheng Zhou Haomin Guo Qingxin Shi Tiancheng E. Song Ian Schomer Yu Liu 《电力系统保护与控制》2021,6(1):55-64
As a key component of an integrated energy system (IES), energy storage can effectively alleviate the problem of
the times between energy production and consumption. Exploiting the benefits of energy storage can improve the
competitiveness of multi-energy systems. This paper proposes a method for day-ahead operation optimization of a
building-level integrated energy system (BIES) considering additional potential benefits of energy storage. Based on
the characteristics of peak-shaving and valley-filling of energy storage, and further consideration of the changes in
the system’s load and real-time electricity price, a model of additional potential benefits of energy storage is
developed. Aiming at the lowest total operating cost, a bi-level optimal operational model for day-ahead operation
of BIES is developed. A case analysis of different dispatch strategies verifies that the addition of the proposed
battery scheduling strategy improves economic operation. The results demonstrate that the model can exploit
energy storage’s potential, further optimize the power output of BIES and reduce the economic cost. 相似文献
114.
Natasha M. van Poppelen Jolique A. van Ipenburg Quincy van den Bosch Jolanda Vaarwater Tom Brands Bert Eussen Frank Magielsen Hendrikus J. Dubbink Dion Paridaens Erwin Brosens Nicole Naus Annelies de Klein Emine Kili Robert M. Verdijk 《International journal of molecular sciences》2021,22(11)
The aim of this study was exploration of the genetic background of conjunctival melanoma (CM) and correlation with recurrent and metastatic disease. Twenty-eight CM from the Rotterdam Ocular Melanoma Study group were collected and DNA was isolated from the formalin-fixed paraffin embedded tissue. Targeted next-generation sequencing was performed using a panel covering GNAQ, GNA11, EIF1AX, BAP1, BRAF, NRAS, c-KIT, PTEN, SF3B1, and TERT genes. Recurrences and metastasis were present in eight (29%) and nine (32%) CM cases, respectively. TERT promoter mutations were most common (54%), but BRAF (46%), NRAS (21%), BAP1 (18%), PTEN (14%), c-KIT (7%), and SF3B1 (4%) mutations were also observed. No mutations in GNAQ, GNA11, and EIF1AX were found. None of the mutations was significantly associated with recurrent disease. Presence of a TERT promoter mutation was associated with metastatic disease (p-value = 0.008). Based on our molecular findings, CM comprises a separate entity within melanoma, although there are overlapping molecular features with uveal melanoma, such as the presence of BAP1 and SF3B1 mutations. This warrants careful interpretation of molecular data, in the light of clinical findings. About three quarter of CM contain drug-targetable mutations, and TERT promoter mutations are correlated to metastatic disease in CM. 相似文献
115.
KeShun Liu Frank Orthoefer Edward A. Brown 《Journal of the American Oil Chemists' Society》1995,72(2):189-192
Ten soybean genotypes grown in 1992 with seed size ranging from 7.6 to 30.3 g/100 seeds and maturity group V or VI were selected
and tested for oil and protein content and for fatty acid composition. In these germplasm, protein varied from 39.5 to 50.2%,
oil, 16.3 to 21.6%, and protein plus oil, 59.7 to 67.5%. Percentages of individual fatty acids relative to total fatty acids
varied as follows: palmitic, 11.0 to 12.8; stearic, 3.2 to 4.7; oleic, 17.6 to 24.2; linoleic, 51.1 to 56.3 and linolenic,
6.9 to 10.0. Seed size showed no significant correlations with individual saturated fatty acids, protein or oil content. However,
significant correlations were found between seed size and individual unsaturated fatty acids: positive with oleic, and negative
with linoleic and linolenic. Oil and protein content were negatively correlated with each other. Among the major fatty acids,
only the unsaturated were significantly correlated with each other: negative between oleic and linoleic or linolenic, and
positive between linoleic and linolenic. A subsequent study with soybeans grown in 1993 generally confirmed these findings.
Variation in relative percentages of unsaturated fatty acids andr values for most pairs of relationships were even higher than those obtained from the 1992 crop.
Presented at the 85th AOCS Annual Meeting and Expo, Atlanta, Georgia, May 8–12, 1994. 相似文献
116.
A comparative study of the comminution in rotary and vibratory ball mills using sodium chloride is presented. The many advantages of vibratory over rotary ball milling are outlined and it is shown experimentally that the rate and extent of grinding is higher for the vibratory ball mill. It is further shown that fine particles re-aggregate in the rotary ball mill and ‘cake’ irreversibly. This phenomenon, exclusive to the rotary ball mill, is explained in terms of consolidation and high stress relaxation of the crystals occurring during prolonged grinding. 相似文献
117.
A surfactant‐free method to produce responsive polymer microgels is introduced. As an example, poly(methacrylic acid) hydrogels with varying crosslinking density have been synthesized in bulk and then chopped using a high shear mechanical cutter to form microgel particles dispersed in water. The mechanical cutting technique enables the concentration and particle size distribution of the microgel suspensions to be easily controlled, therefore making the rheology of the suspensions tuneable. The particle size distribution of the dispersions, characterized using light scattering, was dependent on the speed and duration of mechanical cutting. The particle size distribution also depended on the degree of crosslinking of the hydrogel. The higher the crosslinking density, the lower the average mean diameter of the resulting microgel particles. The lower the crosslinking density of the hydrogel, the larger the difference between the maximum and minimum particle size. The time to complete swelling of the particles upon change in pH was measured to be up to 45 s, depending on the particle size. The rheology of the resulting suspensions as a function of pH was investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 104: 1912–1919, 2007 相似文献
118.
Kathy A. Northcott Ian Snape Peter J. Scales Geoff W. Stevens 《Chemical engineering science》2005,60(24):6835-6843
Sludge reduction and dewatering is an important aspect of water and waste water treatment. This is especially true in the case of Australia's Antarctic contaminated site remediation program, where the reduction in volume of wastes to be returned to Australia can lead to significant transport and handling cost savings. The dewatering characterisation of water treatment sludges from an Antarctic contaminated site was conducted using a theory of suspension dewatering developed by Buscall, Landman and White. This theory uses fundamental material properties of compressibility and permeability to determine the diffusivity of a suspension. Diffusivity is a useful property that can be used to directly compare the dewaterability of various sludges. In this investigation, several water treatment sludges were collected and characterised in the field to determine the impact of temperature and additives on compressibility, permeability and diffusivity. The Antarctic sludges were found to be less compressible and less permeable than materials such as mineral suspensions and alum water treatment sludges. Compressibility was found to decrease with the addition of powdered coagulation aids such as bentonite and chitosan. 相似文献
119.
Ian W. Campbell 《European Journal of Lipid Science and Technology》2004,106(5):334-339
Obesity is now recognised as the most prevalent nutritional disorder affecting children. Prevalence rates across Europe have increased sharply in the past decade and the consequences of this are increasingly clear with type 2 diabetes, hyperlipidaemia and hypertension now affecting children in growing numbers. The causes of this modern epidemic are many and involve complex genetic and environmental factors and the traditional view of obesity as a product of laziness and greed is increasingly being challenged. Whatever the causes, prevention and treatment need to be considered with urgency. While personal and parental responsibility remain crucial, it also falls to government to help control powerful environmental pressures which are leading our children into premature ill‐health and mortality. Equally health professionals are increasingly recognising that they have a significant role to play in delivering medical treatment of obesity in children. Successful treatment requires a greater understanding of obesity, causes, and consequences, and of the particular style of approach that is required for children, and their families. The role of weight loss medication remains unclear, but is being examined seriously, such is the need for effective treatment strategies to minimise the incidence and severity of co‐morbid disease. Inaction at any level can no longer be considered a viable option. 相似文献
120.
The cobalt(II) chloride-catalyzed oxidative cleavage of -methylstyrene with oxygen in t-BuOH gives acetophenone and formaldehyde in good yield. The competing reactions between C=C cleavage and formation of polymeric products are strongly affected by the solvent, cobalt catalyst and concentration used, as well as the reaction temperature. A free radical mechanism involving a cyclic peroxide intermediate is proposed to give the cleavage products. Oxidation of various alkenes using CoCl2/t-BuOH/O2 system shows that only activated styrenes can be oxidized effectively. The reactivity of various styrenes and their selectivity towards giving cleavage products or polymers are strongly influenced by the electronic and steric properties of the substrate. 相似文献