Predicting the crushing behaviour of composite material using high-fidelity finite element modelling

The capability to numerically model the crushing behaviour of composite structures will enable the efficient design of structures with high specific energy absorption capacity. This is particularly relevant to the aerospace and automotive industries where cabin structures need to be shown to be crashworthy. In this paper, a three-dimensional damage model is presented, which accurately represents the behaviour of composite laminates under crush loading. Both intralaminar and interlaminar failure mechanisms are taken into account. The crush damage model was implemented in ABAQUS/Explicit as a VUMAT subroutine. Numerical predictions are shown to agree well with experimental results, accurately capturing the intralaminar and interlaminar damage for a range of stacking sequences, triggers and composite materials. The use of measured material parameters required by the numerical models, without the need to ‘calibrate’ this input data, demonstrates this computational tool's predictive capabilities

ALEA: Fine-Grain Energy Profiling with Basic Block Sampling

Energy efficiency is an essential requirement for all contemporary computing systems. We thus need tools to measure the energy consumption of computing systems and to understand how workloads affect it. Significant recent research effort has targeted direct power measurements on production computing systems using on-board sensors or external instruments. These direct methods have in turn guided studies of software techniques to reduce energy consumption via workload allocation and scaling. Unfortunately, direct energy measurements are hampered by the low power sampling frequency of power sensors. The coarse granularity of power sensing limits our understanding of how power is allocated in systems and our ability to optimize energy efficiency via workload allocation.
We present ALEA, a tool to measure power and energy consumption at the granularity of basic blocks, using a probabilistic approach. ALEA provides fine-grained energy profiling via sta- tistical sampling, which overcomes the limitations of power sens- ing instruments. Compared to state-of-the-art energy measurement tools, ALEA provides finer granularity without sacrificing accuracy. ALEA achieves low overhead energy measurements with mean error rates between 1.4% and 3.5% in 14 sequential and paral- lel benchmarks tested on both Intel and ARM platforms. The sampling method caps execution time overhead at approximately 1%. ALEA is thus suitable for online energy monitoring and optimization. Finally, ALEA is a user-space tool with a portable, machine-independent sampling method. We demonstrate two use cases of ALEA, where we reduce the energy consumption of a k-means computational kernel by 37% and an ocean modelling code by 33%, compared to high-performance execution baselines, by varying the power optimization strategy between basic blocks.

A design strategy of large grain lithium-rich layered oxides for lithium-ion batteries cathode

Li-rich materials are considered the most promising for Li-ion battery cathodes, as high capacity can be achieved. However, poor cycling stability is a critical drawback that leads to poor capacity retention. Here a strategy is used to synthesize a large-grain lithium-rich layered oxides to overcome this difficulty without sacrificing rate capability. This material is designed with micron scale grain with a width of about 300 nm and length of 1-3 μm. This unique structure has a better ability to overcome stress-induced structural collapse caused by Li-ion insertion/extraction and reduce the dissolution of Mn ions, which enable a reversible and stable capacity. As a result, this cathode material delivered a highest discharge capacity of around 308 mAh g^-1 at a current density of 30 mA g^-1 with retention of 88.3% (according to the highest discharge capacity) after 100 cycles, 190 mAh g^-1 at a current density of 300 mA g^-1 and almost no capacity fading after 100 cycles. Therefore, Lithium-rich material of large-grain structure is a promising cathode candidate in Lithium-ion batteries with high capacity and high cycle stability for application. This strategy of large grain may furthermore open the door to synthesize the other complex architectures for various applications.

Silicon, the silver bullet for mitigating biotic and abiotic stress, and improving grain quality, in rice?

Adequate silicon fertilization greatly boosts rice yield and mitigates biotic and abiotic stress, and improves grain quality through lowering the content of cadmium and inorganic arsenic. This review on silicon dynamics in rice considers recent advances in our understanding of the role of silicon in rice, and the challenges of maintaining adequate silicon fertility within rice paddy systems. Silicon is increasingly considered as an element required for optimal plant performance, particularly in rice. Plants can survive with very low silicon under laboratory/glasshouse conditions, but this is highly artificial and, thus, silicon can be considered as essential for proper plant function in its environment. Silicon is incorporated into structural components of rice cell walls were it increases cell and tissue rigidity in the plant. Structural silicon provides physical protection to plants against microbial infection and insect attack as well as reducing the quality of the tissue to the predating organisms. The abiotic benefits are due to silicon's effect on overall organ strength. This helps protect against lodging, drought stress, high temperature (through efficient maintenance of transpiration), and photosynthesis by protecting against high UV. Furthermore, silicon also protects the plant from saline stress and against a range of toxic metal stresses (arsenic, cadmium, chromium, copper, nickel and zinc). Added to this, silicon application decreases grain concentrations of various human carcinogens, in particular arsenic, antimony and cadmium. As rice is efficient at stripping bioavailable silicon from the soil, recycling of silicon rich rice straw biomass or addition of inorganic silicon fertilizer, primarily obtained from iron and steel slag, needs careful management. Silicon in the soil may be lost if the silicon-cycle, traditionally achieved via composting of rice straw and returning it to the land, is being broken. As composting of rice straw and incorporation of composted or non-composted straw back to land are resource intensive activities, these activities are declining due to population shifts from the countryside to cities. Processes that accelerate rice straw composting, therefore, need to be identified to aid more efficient use of this resource. In addition, rice genetics may help address declining available silicon in paddy soils: for example by selecting for characteristics during breeding that lead to an increased ability of roots to access recalcitrant silicon sources from soil and/or via selection for traits that aid the maintenance of a high silicon status in shoots. Recent advances in understanding the genetic regulation of silicon uptake and transport by rice plants will aid these goals.

Genetic mapping of the rice ionome in leaves and grain:Identification of QTLs for 17 elements including arsenic, cadmium, iron and selenium

Research into the composition of cereal grains is motivated by increased interest in food quality. Here multi-element analysis is conducted on leaves and grain of the Bala x Azucena rice mapping population grown in the field. Quantitative trait loci (QTLs) for the concentration of 17 elements were detected, revealing 36 QTLs for leaves and 41 for grains. Epistasis was detected for most elements. There was very little correlation between leaf and grain element concentrations. For selenium, lead, phosphorus and magnesium QTLs were detected in the same location for both tissues. In general, there were no major QTL clusters, suggesting separate regulation of each element. QTLs for grain iron, zinc, molybdenum and selenium are potential targets for marker assisted selection to improve seed nutritional quality. An epistatic interaction for grain arsenic also looks promising to decrease the concentration of this carcinogenic element. © Springer Science+Business Media B.V. 2009.

Determination of the Mycotoxin Content in Distiller's Dried Grain with Solubles Using a Multianalyte UHPLC-MS/MS Method

There are more than 300 potential mycotoxins that can contaminate food and feed and cause adverse effects in humans and animals. The data on the co-occurrence of mycotoxins in novel animal feed materials, such as distiller's dried grain with solubles (DDGS), are limited. Thus, a UHPLC-MS/MS method for the quantitation of 77 mycotoxins and other fungal metabolites was used to analyze 169 DDGS samples produced from wheat, maize, and barley and 61 grain samples. All DDGS samples analyzed were contaminated with 13-34 different mycotoxins. Fumonisins were present in all 52 maize DDGS samples (81.0-6890 μg/kg for fumonisin B1), and deoxynivalenol was present in all 99 wheat DDGS samples (39.3-1120 μg/kg). A number of co-occurring mycotoxins were also identified. Due to the high co-occurrence of mycotoxins, routine screening of the animal feed ingredients is highly recommended to allow the highlighted risks to be effectively managed.

Availability and transfer to grain of As, Cd, Cu, Ni, Pb and Zn in a barley agri-system: Impact of biochar, organic and mineral fertilizers

With biochar becoming an emerging soil amendment and a tool to mitigate climate change, there are only a few studies documenting its effects on trace element cycling in agriculture. Zn and Cu are deficient in many human diets, whilst exposures to As, Pb and Cd need to be decreased. Biochar has been shown to affect many of them mainly at a bench or greenhouse scale, but field research is not available. In our experiment we studied the impact of biochar, as well as its interactions with organic (compost and sewage sludge) and mineral fertilisers (NPK and nitrosulfate), on trace element mobility in a Mediterranean agricultural field (east of Madrid, Spain) cropped with barley. At harvesting time, we analysed the soluble fraction, the available fraction (assessed with the diffusive gradients in thin gels technique, DGT) and the concentration of trace elements in barley grain. No treatment was able to significantly increase Zn, Cu or Ni concentration in barley grain, limiting the application for cereal fortification. Biochar helped to reduce Cd and Pb in grain, whereas As concentration slightly increased. Overall biochar amendments demonstrated a potential to decrease Cd uptake in cereals, a substantial pathway of exposure in the Spanish population, whereas mineral fertilisation and sewage sludge increased grain Cd and Pb. In the soil, biochar helped to stabilise Pb and Cd, while marginally increasing As release/mobilisation. Some of the fertilisation practises or treatments increased toxic metals and As solubility in soil, but never to an extent high enough to be considered an environmental risk. Future research may try to fortify Zn, Cu and Ni using other combinations of organic amendments and different parent biomass to produce enriched biochars.

Validation of a 3D damage model for predicting the response of composite structures under crushing loads

A 3D intralaminar continuum damage mechanics based material model, combining damage mode interaction and material nonlinearity, was developed to predict the damage response of composite structures undergoing crush loading. This model captures the structural response without the need for calibration of experimentally determined material parameters. When used in the design of energy absorbing composite structures, it can reduce the dependence on physical testing. This paper validates this model against experimental data obtained from the literature and in-house testing. Results show that the model can predict the force response of the crushed composite structures with good accuracy. The simulated energy absorption in each test case was within 12% of the experimental value. Post-crush deformation and the damage morphologies, such as ply splitting, splaying and breakage, were also accurately reproduced. This study establishes the capability of this damage model for predicting the responses of composite structures under crushing loads.

Localization and regulation by GABA of anion transporter present in pollen grain protoplasts and tube of Arabidopsis thaliana

Tese de doutoramento, Biologia (Biologia do Desenvolvimento), Universidade de Lisboa, Faculdade de Ciências, 2015

Brewer's spent grain from different types of malt: Evaluation of the antioxidant activity and identification of the major phenolic compounds

The antioxidant activity and phenolic composition of brewer's spent grain (BSG) extracts obtained by microwave-assisted extraction from twomalt types (light and darkmalts) were investigated. The total phenolic content (TPC) and antioxidant activity among the light BSG extracts (pilsen, melano, melano 80 and carared)were significantly different (p b 0.05) compared to dark extracts (chocolate and black types), with the pilsen BSG showing higher TPC (20 ± 1 mgGAE/g dry BSG). In addition, the antioxidant activity assessed by 2,2-diphenyl- 1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and deoxyribose assays decreased as a result of increasing kilning temperatures in the following order: pilsen N melano N melano 80 N carared N chocolate N black. HPLC-DAD/ESI-MS/MS analysis indicated the presence of phenolic acids, such as ferulic, p-coumaric and syringic acids, as well as several isomeric ferulate dehydrodimers and one dehydrotrimer. Chocolate and black extracts, obtained frommalts submitted to the highest kilning temperatures, showed the lowest levels of ferulic and p-coumaric acids. These results suggested that BSG extracts from pilsen malt might be used as an inexpensive and good natural source of antioxidants with potential interest for the food, pharmaceutical and/or cosmetic industries after purification.

DU GRAIN À LA MUSIQUE : MANIPULATIONS EN TEMPS RÉEL

Dans cet article, nous présenterons une étude comparative de quelques techniques de manipulation du signal comme la Transformée de Fourier à Court Terme, la Synthèse Granulaire Asynchrone et PSOLA, notamment dans le cadre de leur utilisation en temps réel. Nous présenterons succinctement le fonctionnement de ces trois méthodes dans l’environnement Max / MSP avec l’utilisation de la librairie GABOR. La manipulation des paramètres propres à chaque méthode a des conséquences sur les variables musicales, et l’utilisation de ces méthodes implique des corrélations entre les paramètres techniques du traitement du signal et des attributs musicaux spécifiques. Ainsi, nous essayerons d’explorer les espaces des paramètres et de la perception musicales entre le temps, la période et le spectre (les rythmes, les fréquences et les timbres) en comparant les différentes méthodes en vue de leur croisement dans un système de traitement commun.

Interactions of dietary whole-grain intake with fasting glucose- and insulin-related genetic loci in individuals of European descent: a meta-analysis of 14 cohort studies.

Whole-grain foods are touted for multiple health benefits, including enhancing insulin sensitivity and reducing type 2 diabetes risk. Recent genome-wide association studies (GWAS) have identified several single nucleotide polymorphisms (SNPs) associated with fasting glucose and insulin concentrations in individuals free of diabetes. We tested the hypothesis that whole-grain food intake and genetic variation interact to influence concentrations of fasting glucose and insulin. Via meta-analysis of data from 14 cohorts comprising ∼ 48,000 participants of European descent, we studied interactions of whole-grain intake with loci previously associated in GWAS with fasting glucose (16 loci) and/or insulin (2 loci) concentrations. For tests of interaction, we considered a P value <0.0028 (0.05 of 18 tests) as statistically significant. Greater whole-grain food intake was associated with lower fasting glucose and insulin concentrations independent of demographics, other dietary and lifestyle factors, and BMI (β [95% CI] per 1-serving-greater whole-grain intake: -0.009 mmol/l glucose [-0.013 to -0.005], P < 0.0001 and -0.011 pmol/l [ln] insulin [-0.015 to -0.007], P = 0.0003). No interactions met our multiple testing-adjusted statistical significance threshold. The strongest SNP interaction with whole-grain intake was rs780094 (GCKR) for fasting insulin (P = 0.006), where greater whole-grain intake was associated with a smaller reduction in fasting insulin concentrations in those with the insulin-raising allele. Our results support the favorable association of whole-grain intake with fasting glucose and insulin and suggest a potential interaction between variation in GCKR and whole-grain intake in influencing fasting insulin concentrations.

Pollen and grain size records in abyssal sediments of the northwest Pacific Ocean as proxies of Plio-Pleistocene climate change /

A distinctive period of global change occurred during the PUocene between the warm Miocene and subsequent Quaternary cooling. Samples from Ocean Drilling Project Site 11 79 (-5586 mbsl, 41°4'N, 159°57'E), Site 881 (-5765 mbsl, 47°6.133'N, 161°29.490'E) and Site 882 (-3255 mbsl, 50°22'N, 167°36'E) were studied to determine the magnitude and composition ofterrigenous flux to the western mid-latitude North Pacific and its relation to climate change in East Asia since the mid-Pliocene. Dust-sized particles (including pollen), sourced from the arid regions and loess plateaus in East Asia are entrained by prevailing westerly winds and transported to the midlatitude northwest North Pacific Ocean. This is recorded by peaks in the total concentration of pollen and spores, as well as the mean grain size of allochthonous and autochthonous silicate material in abyssal marine sediments. Aridification of the Asian interior due to the phased uplift of the Himalayan-Tibetan Plateau created the modem East Asian Monsoon system dominated by a strengthening of the winter monsoon. The winter monsoon is further enhanced during glacials due to the expansion of desert and steppe environments at the expense ofwoodlands and forests recorded by the composition of palynological assemblages. The late Pliocene-Pleistocene glacials at ODP Sites 1 179, 881, and 882 are characterized by increases in grain size, magnetic susceptibility, pollen and spore concentrations around 3.5-3.3, 2.6-2.4, 1.7-1.6, and 0.9-0.7 Ma (ages based on magnetostratigraphic and biostratigraphic datums). The peaks during these times are relatively rich in pollen taxa derived primarily from steppe and boreal vegetation zones, recording cool, dry climates. The overall size increase of sediment and abundance of terrestrial palynomorphs record enhanced wind strength. The increase in magnitude of pollen and spore concentrations as well as grain size record global cooling and Northern Hemisphere glaciation. The peaks in grain size as well as pollen and spore abundance in marine sediments correlate with the mean grain size of loess in East Asia, consistent with the deflation of unarmoured surfaces during glacials. The transport of limiting nutrients to marine environments enhanced sea surface productivity and increased the rate of sediment accumulation.

HG 244.40-244.50-A Thin Section

Dark brown sediment with sub-angular to sub-rounded clasts. Rotation structures and lineations are common. Clasts ranging from small to large in size. Many large grains are fractured. Minor amounts of grain stacking and crushing can be seen. A few clay and organic rich domains can be seen.