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Aflatoxin contamination in corn (Zea maysL.) grain negatively affects human and animal health. This research was conducted to determine if interactions among cultural practices influence aflatoxin accumulation on inoculated and naturally infested corn. Season‐long irrigation thresholds (full irrigation at −50 kPa vs. deficit irrigation at −125 kPa), planting date (late March vs. late April), and hybrid selection (conventional short‐season, drought‐tolerant full‐season, or conventional full‐season) were evaluated for their influence on aflatoxin accumulation. Experiments were conducted on a Marietta fine sandy loam and a Leeper silty clay loam near Starkville and Verona, MS, in 2016 and 2017, respectively. Needle‐inoculated and noninoculated ears were harvested from each plot. Noninoculated samples indicated that year (p= .0013) and planting date × hybrid type interaction (p= .0263) affected aflatoxin accumulation. The first year of the study produced greater average aflatoxin levels than the second year due to hotter and drier growing conditions for noninoculated samples. Pooled over years, planting later only affected conventional short‐season hybrids, increasing aflatoxin levels by 77% in naturally infested corn. Inoculated samples were affected by a year × planting date interaction (p= .0044) and a planting date × hybrid type interaction (p= .0032). Planting in March 2016 increased aflatoxin more than threefold compared with planting in April, whereas there was no difference between planting date in 2017. Overall, year, planting date, and hybrid type affected aflatoxin levels.

The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community‐sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of maximizing the reuse value of paleoclimate data sets, particularly for synthesis work and comparison to climate model simulations. Initiated by the LinkedEarth project, the process to elicit a reporting standard involved an international workshop in 2016, various forms of digital community engagement over the next few years, and grassroots working groups. Participants in this process identified important properties across paleoclimate archives, in addition to the reporting of uncertainties and chronologies; they also identified archive‐specific properties and distinguished reporting standards for new versus legacy data sets. This work shows that at least 135 respondents overwhelmingly support a drastic increase in the amount of metadata accompanying paleoclimate data sets. Since such goals are at odds with present practices, we discuss a transparent path toward implementing or revising these recommendations in the near future, using both bottom‐up and top‐down approaches. Standardizing the way data are described and shared is key to accelerating the progress of science. Building on recent advances in paleoceanography and paleoclimatology, we present the first community‐led reporting standard for such datasets. The Paleoclimate Community reporTing Standard (PaCTS) provides guidelines as to which information should be included when reporting data from various paleoclimate archives, as well as themes common to many fields, like uncertainty and other site‐specific information. The ultimate goal of this effort is to (1) make these datasets more re‐usable over the long term, and (2) provide a roadmap for implementing and revising the standard, as the field of paleoclimatology and its practitioners both evolve. The requirements are driven by the differing needs of data producers and the data consumers, who often have different goals in mind. Thus, agreeing on and writing up these requirements involves building consensus among the community to decide on their present and future goals. First version of a crowdsourced reporting standard for paleoclimate dataThe standards arose through collective discussions, both in person and online, and via an innovative social platformThe standard helps meet the interoperability and reuse criteria of FAIR (Findable, Accessible, Interoperable, and Reusable)

GaSb and alloys based on the 6.1 Å family can be grown metamorphically on substrates such as GaAs allowing for the realization of several multijunction solar cell designs. This paper investigates the molecular beam epitaxy growth, crystal quality, and device performance of AlxGa1-xSb-based single-junction solar cells grown on GaAs substrates. The focus is on the optimization of the growth of AlxGa1-xSb on GaAs (001) substrates in order to minimize the threading dislocation density resulting from the large lattice mismatch between GaSb and GaAs. Utilizing optimum growth conditions, solar cells with absorbing layers of different AlxGa1-xSb compositions are studied and compared to control cells grown on lattice-matched GaSb substrates. GaSb, Al0.15Ga0.85Sb, and Al0.5Ga0.5Sb solar cells grown on GaAs substrates show open-circuit voltages of 0.16, 0.17, and 0.35 V, respectively. Furthermore, the lattice-mismatched cells demonstrate promising carrier collection with comparable spectral response to lattice-matched control cells grown on GaSb.

Director interlocks, which occur when companies have directors in common, have concerned shareholders, the public and legislators since the early 1900s. The purpose of this paper is to analyse the interlocking directorships of the Top 40 companies listed on the Johannesburg Stock Exchange using small world theory and compare the results to research on interlocks in Italian, French, German, United Kingdom (UK) and United States (US) companies. South Africa was found to be closest to Italy, between the low-density models of the UK and the US, and the significantly higher-density models of Germany and France. This suggests that rather than just the two models (low density and high density), there is a continuum currently reflected with the UK and the US at one end, then South Africa and Italy, and then France and Germany at the other end. The presence of directors with multiple directorships indicates that the threats and benefits associated with multiple directorships may exist in South Africa.

Bioelectrical impedance analysis (BIA) and especially its derived parameter phase angle have been widely used in different populations. The variability of BIA measures has often been cited as a major limitation for its clinical use in evaluating nutritional status and overall health of patients. Cancer patients often present with malnourishment and cachexia, which complicate the course of treatment and affect outcomes. PubMed, CINAHL, EBSCO and Cochrane Library have been searched for relevant publications in English for BIA in cancer patients. Out of 197 total results, 27 original research articles related to BIA measures in cancer patients were included in this review. Studies indicate that the use of BIA and phase angle measures can benefit in the clinical management of cancer patients in multiple ways: in the prevention; diagnosis; prognosis; and outcomes related to treatments that affect nutritional and overall health status. Phase angle and fat-free mass measures were most commonly evaluated and correlated with nutritional status and survival rate. One limitation of BIA measures is the high interpatient variability which requires careful interpretation of results in the context of the individual patient rather than comparison with population data. The BIA and phase angle provide practitioners for the evaluation of nutritional and overall health status in cancer patients with a convenient and non-invasive technique and should be encouraged.

Metal matrix composites are known for their high strength, fatigue resistance, and wear resistance. The coefficient of thermal expansion between the reinforcement and matrix can result in thermal stresses during thermal cycling. In this paper we quantify the evolution of cavitation damage in SiC particle reinforced aluminium alloy matrix composite subjected to thermal cycling by X-ray synchrotron tomography at the advanced photon source at the Argonne National Laboratory. It will be shown that, while surface examination did not show significant damage, X-ray synchrotron tomography enabled us to resolve and quantify the amount and nature of cavitation with increasing thermal cycling. The influence of the microstructure in damage initiation and evolution is discussed.

The National Oceanography Centre (NOC), in collaboration with the UK Met Office, has developed an operational suite of models for the Irish Sea. This work has extended this suite to include a coastal vulnerability early warning system for the Sefton Coast in Liverpool Bay. The system is designed to forecast when the offshore hydrodynamic and wave conditions exceed thresholds for low, moderate and high hazard of storm impact and also gives an indication of the extent of dune erosion. The model simulates a 72h period (yesterday:today:tomorrow), allowing a 24h spin-up period and 48h forecast. The main idea of the system is to use forecasts for impending storms to assist with management decisions.

The microstructure, tensile, and creep behavior of bulk Sn-3.5Ag solder were studied as a function of cooling rate. Controlled cooling rates were obtained by cooling specimens in different media: water, air, or furnace. The cooling rate significantly affected secondary dendrite arm size and spacing of the tin-rich phase, as well as the morphology of Ag3Sn. Ag3Sn was relatively spherical at the fastest cooling rate and had a needle-like morphology at the slowest cooling rate. Both the yield strength in tension and creep resistance of Sn-3.5Ag solder increased with increasing cooling rate while the strain-to-failure decreased. In this study, the mechanical behavior was correlated with the observed microstructure, creep-stress exponents, and fracture behavior, in order to understand the underlying damage mechanisms.

Many of the targeted applications for powder-metallurgy materials, particularly in the automotive industry, undergo cyclic loading. It is, therefore, essential to examine the fatigue mechanisms in these materials. The mechanisms of fatigue-crack initiation and propagation in ferrous powder-metallurgy components have been investigated. The fatigue mechanisms are controlled primarily by the inherent porosity present in these materials. Since most, if not all, fatigue cracks initiate and propagate at the specimen surface, surface replication was used to determine the role of surface porosity in relation to fatigue behavior. Surface replication provides detailed information on both initiation sites and on the propagation path of fatigue cracks. The effect of microstructural features such as pore size and pore shape, as well as the heterogeneous microstructure on crack deflection, was examined and is discussed. Fracture surfaces were examined to elucidate a mechanistic understanding of fatigue processes in these materials.

Abstract:  Large-eddy simulations are used to investigate unsteady low-speed buoyant jet diffusion flames. The numerical method is based on a predictor-corrector approach for low Mach number compressible flows. The infinitely fast chemistry of “mixed-is-burned” is adopted as the combustion model. The dynamical phenomena of puffing and formation of large vortex structures are well captured. The entire flow oscillates and the dominating low-frequency is independent of locations in the flow field, characteristic of a self-excited global instability. The pulsation frequencies are found to be insensitive to the heat release rate and the coflow velocity. In general, the buoyancy-sustained shear-layer instability can be best described by the Richardson number, as in the experimental observation of Cetegen. A quantitative description of the flow field is given by the instantaneous, mean and rms profiles of the axial velocity, temperature, major species and mixture fraction. Off-axis peaks exist in the radial profiles of the mean axial velocity, temperature and their corresponding rms quantities. The existence of inflection points in the mean velocity distributions, indicative of large-scale vortical structures, is consistent with the observation of Lingens et al.

A large-eddy simulation of flow in an open channel has been carried out at the moderate Froude number, Fr = 0.66, and Reynolds number. Re = 20,800. A resolution has been used that allowed the simulation to be carried out on a workstation; thus enabling the results obtained to be viewed within an engineering context. The code used treats the free-surface exactly and allows it to freely deform with the underlying turbulence. The turbulent features found in this study are consistent with those found both by experimental observations and direct numerical simulations at lower Reynolds numbers where the free-surface has been treated as a stress free rigid lid.

Coastal management and engineering applications require data that quantify the nature and magnitude of changes in nearshore bathymetry. However, bathymetric surveys are usually infrequent due to high costs and complex logistics. This study demonstrates that ground‐based X‐band radar offers a cost‐effective means to monitor nearshore changes at relatively high frequency and over large areas. A new data quality and processing framework was developed to reduce uncertainties in the estimates of radar‐derived bathymetry and tested using data from an 18‐months installation at Thorpeness (UK). In addition to data calibration and validation, two new elements are integrated to reduce the influence of data scatter and outliers: (a) an automated selection of periods of “good data” and (b) the application of a depth‐memorystabilization. For conditions when the wave height is >1 m, the accuracy of the radar‐derived depths is shown to be ±0.5 m (95% confidence interval) at 40 × 40‐m spatial resolution. At Thorpeness, radar‐derived bathymetry changes exceeding this error were observed at time scales ranging from 3 weeks to 6 months. These data enabled quantification of changes in nearshore sediment volume at frequencies and spatial cover that would be difficult and/or expensive to obtain by other methods. It is shown that the volume of nearshore sediment movement occurring at time scale as short as few weeks are comparable with the annual longshore transport rates reported in this area. The use of radar can provide an early warning of changes in offshore bathymetry likely to impact vulnerable coastal locations. Near the shore, waves and currents can cause natural changes in seabed elevation (due to removal or deposition of mud, sand, and gravel). On the other hand, changes in seabed elevation can alter the waves approaching the shore and influence the location and amount of coastal erosion. Measurements of these changes are required for coastal management and a wide range of engineering works. However, surveys of the seabed are usually infrequent owing to high costs and logistical difficulties. This paper analyses data from a marine radar installed on a cliff top to produce a series of seabed elevation (bathymetric) maps off the Thorpeness coast (UK). A new data quality assessment was developed to produce improved estimates of water depth. Results demonstrate that radar can offer a cost‐effective alternative to conventional surveys and enable frequent monitoring of the seabed over large areas. The use of radar in the present study enabled the measurement of changes in nearshore seabed elevation within periods as short as 3 weeks. Radar‐derived bathymetric maps can provide an early warning of seabed changes and allow more time to plan and implement responses to mitigate the impacts of coastal erosion. Uncertainty in radar‐derived bathymetry (2.5–10‐m depths) was greatly reduced using a new data processing and quality control frameworkBathymetry changes assessed for periods as short as 3 weeks were shown to be accurate to ±0.50 m at a 40 × 40‐m resolutionThe volume of nearshore sediment movement over a few weeks was comparable with annual longshore transport rates reported in this area Uncertainty in radar‐derived bathymetry (2.5–10‐m depths) was greatly reduced using a new data processing and quality control framework Bathymetry changes assessed for periods as short as 3 weeks were shown to be accurate to ±0.50 m at a 40 × 40‐m resolution The volume of nearshore sediment movement over a few weeks was comparable with annual longshore transport rates reported in this area

Turbulent flow in a narrow open channel is investigated using the large-eddy simulation (LES) technique in which the surface is allowed to freely deform. A relatively large Reynolds number of 90,400 (defined as 4RUmean/) is used in the simulation and it is shown that good resolution is required in order to reproduce the effects of the turbulence-driven secondary currents. The simulated results are in good agreement with experimental measurements and previous calculations.

Progressive changes in the roundness of the femoral head were noted during the healing phase of hips with Legg-Calvé-Perthes disease. Forty-nine of 136 hips studied became progressively rounder, and 15 hips became progressively flatter after onset of reossification of the femoral head. The femoral head was more likely to undergo progressive flattening in older patients, in those with more severe lateral pillar involvement, and in those with prolonged reossification. These changes occurred during a 3− to 4-year reossification period after cessation of treatment.

SPRINT is a transaxial tomograph for use with single photon emitting nuclides. It consists of an aperture cylinder surrounded by a ring of NaI(Tl) detectors. The singles count rate for each detector is correlated with the aperture cylinder position. This provides a view of the image plane activity distribution from each detector's perspective. These views are then combined to form a slice image. Preliminary operation of the device has recently been accomplished. The structure of operation and calibration procedures has been defined. The statistical behavior of single detector data agrees with expectations. Individual point source data for a variety of positions agree with calculations for both resolution and sensitivity. These data arrays have been used with a modified ART routine to provide two dimensional source images.

This paper dcsribes a Large Eddy Simulation of steady uniform flow in a symmetric compound channel of trapezoidal cross-section with flood plains at a Reynolds number of 430.000. The simulation captures the complex interaction between the main channel and the flood plains and predicts the bed stress distribution, velocity distribution, and the secondary circulation across the floodplain. The results are compared with experimental data from the SERC Flood Channel Facility at Hydaulics Research Ltd, Wallingford, England.

A Large Eddy Simulation of turbulent flow in a compound open channel with one floodplain is reported for a Reynolds number of approximately 42000. The results are in good agreement with experimental measurements and previous numerical calculations. The mean velocity field, secondary circulation field, bed stress distribution, and lateral stress distribution are presented in detail.

Joining technology is critical to manufacturing and fabrication industries, since it greatly influences the design, assembly and ultimate competitiveness of the product. In particular, adhesive bonding is now attracting strong interest from many industries. This trend is further strengthened by dramatic advances in new materials, many of which cannot be joined by conventional means.

A method is proposed for isolating the two constants required to quantify the creep strains caused by cyclic histories of stress. These constants can be determined from the results of a single cyclic creep test together with data from constant stress tests.

A method is proposed for estimating structural creep deformation due to histories of cyclic proportional loading. The method applies to structures composed of materials whose creep strain due to constant uniaxial stress is given by an equation of the form ε(t)/ε0={σ/σ0}n{t/t0}m Knowledge of the form of the creep law for time-varying stress is not required, as use is made of an effective stress obtained from a single cyclic creep test.

In this paper the deformations of a beam subject to cyclic bending moment and a thick-walled cylinder subject to cyclic internal pressure are investigated for an elastic/time hardening/perfectly plastic material. Bounds [1, 2] are computed on the work done by the applied loads over a cycle when the material has reached a cyclic state of stress. The bounds provide the extreme states when the cycle time is either large or small compared with a characteristic time of the material. It is found that the difference between the bounds is generally very small. This result is discussed in relation to recent work by Williams and Leckie [3].

The paper describes the salient features of a three-dimensional finite difference code at present under development for Large Eddy Simulation of free-surface turbulence. It is essential in this application that the numerical approximations conserve mass, momentum, and kinetic + potential energy while allowing for large movements of the free surface and these are presented in detail for cells cut by the surface. The surface advancement is by a combined Volume-of-Fluid and height function method which conserves mass exactly over finite time steps, but does not permit breaking waves. Momentum is advanced by control volume techniques, and the potential singularity caused by very small surface cells is avoided by a new split-merge technique which is numerically stable. Results are presented for a two-dimensional inviscid large amplitude wave in a periodic box.

The adiabatic wall temperature distribution in nozzles with gas injection through a peripheral slot at the entrance was investigated. Experimental wall temperature distributions were measured in a series of hot gas (hydrogen-air combustion as the primary source) tests with three geometrically different channels—a constant area duct, a gradually converging nozzle, and a rapidly converging nozzle. Cooling effectiveness was found to be significantly higher for the rapidly converging geometry. Prediction of recovery temperature distributions under the test conditions with available boundary layer computer programs was then investigated. Predicted results were consistently higher than measured. Significantly improved agreement between predicted and measured results was achieved by introducing effective initial temperature profiles in the injectant to account for gross mixing between the injectant gas (nitrogen) and free stream gas at the injection station.

The relationship between the reference stress concept and the nesting surfaces of Calladine and Drucker is examined and the implications for nonisothermal creep are discussed. A method for evaluating a reference stress and temperature is described, which it is argued is more rigorous than methods previously proposed.

The influence of related constitutive equations upon the stress-redistribution times for a simple two-bar structure is such that the time-hardening model is unlikely to provide reliable estimates of the stress-redistribution time for structures composed of a wider class of materials.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

An infinite system of linear differential equations of the form $$\dot{x}$$ = Ax + f, x(0) = y is considered, where x, y and f are infinite column vectors in E, and A is a constant infinite matrix defining a bounded operator on E, where E is l1, (c0), or l∞. Explicit error bounds are obtained for the approximation of the solution of the infinite system by the solutions of the finite truncated systems.