308 research outputs found

    Development and evaluation of mould for double curved concrete elements

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    The present paper describes a concept for a reconfigurable mould surface which is designed to fit the needs of contemporary architecture. The core of the concept presented is a dynamic surface manipulated into a given shape using a digital signal created directly from the CAD drawing of the design. This happen fast, automatic and without production of waste, and the manipulated surface is fair and robust, eliminating the need for additional, manual treatment. Limitations to the possibilities of the flexible form are limited curvature and limited level of detail, making it especially suited for larger, double curved surfaces like facades or walls, where the curvature of each element is relatively small in comparison to the overall shape

    Replicability of nitrogen recommendations from ramped calibration strips in winter wheat

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    Ramped calibration strips have been suggested as a way for grain producers to determine nitrogen needs more accurately. The strips use incrementally increasing levels of nitrogen and enable producers to conduct an experiment in each field to determine nitrogen needs. This study determines whether predictions from the program Ramp Analyzer 1.2 are replicable in Oklahoma hard red winter wheat (Triticum aestivum). Predictions are derived from 36 individual strips from on-farm experiments—two pairs of adjacent strips at each of nine winter wheat fields in Canadian County, OK. The two pairs of strips within each field were between 120 and 155 m apart. Each strip was analyzed three times during the 2006–2007 growing season. Nitrogen recommendations from Ramp Analyzer 1.2 are not correlated even for strips that were placed side by side, and recommendations from strips in the same field show no more homogeneity than randomly selected strips throughout the county. The results indicate that ramped calibration strips are unlikely to produce accurate nitrogen requirement predictions at any spatial scale, whether at the county level or for subsections of a single field. In contrast, a procedure that uses only measures from the plot with no nitrogen and the plot with the highest level of nitrogen applied does show replicability. Thus, improvements in the ramped calibration strip technology are needed if it is to become viable.Fertilizer; Nitrogen; Precision agriculture; Ramped calibration strip; Winter wheat

    Population Suppression of Western Corn Rootworm by Adult Control with ULV Malathion

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    ULV malathion (9.7 oz AI/acre) was applied by air to a 16 square-mile area during August of 1968, 1969, and 1970. Adult Diabrotica virgifera LeConte populations were reduced the following season by 39, 54, and 72%. No economic infestations occurred in the treated area the year following any application. Postspray migration of beetles was very limited, but adult migration during the peak emergence period the following season contributed to repopulation of the treated area. Migration and fecundity appear to be density-dependent factors which favor increases under low populations. Area suppression does not appear economically feasible, but adult control in individual fields may be an acceptable alternative to soil insecticides applied for larval control. A model was developed for timing treatments against adults; treatments between Aug. 1–15 should result in adequate population suppression to prevent damage the following season. Mid-August population levels of 1.0 beetle/ plant were an acceptable economic threshold for determining the need for control measures

    Electrical Manipulation of Telecom Color Centers in Silicon

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    Silicon color centers have recently emerged as promising candidates for commercial quantum technology, yet their interaction with electric fields has yet to be investigated. In this paper, we demonstrate electrical manipulation of telecom silicon color centers by fabricating lateral electrical diodes with an integrated G center ensemble in a commercial silicon on insulator wafer. The ensemble optical response is characterized under application of a reverse-biased DC electric field, observing both 100% modulation of fluorescence signal, and wavelength redshift of approximately 1.4 GHz/V above a threshold voltage. Finally, we use G center fluorescence to directly image the electric field distribution within the devices, obtaining insight into the spatial and voltage-dependent variation of the junction depletion region and the associated mediating effects on the ensemble. Strong correlation between emitter-field coupling and generated photocurrent is observed. Our demonstration enables electrical control and stabilization of semiconductor quantum emitters

    Operando XAS/XRD and Raman Spectroscopic Study of Structural Changes of the Iron Molybdate Catalyst during Selective Oxidation of Methanol

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    The structural changes of an iron molybdate/molybdenum oxide (Mo/Fe=2.0) catalyst for the selective oxidation of methanol to formaldehyde were studied using combined operando X‐ray absorption spectroscopy (XAS) and X‐ray diffraction (XRD) as well as operando Raman spectroscopy. Under operating conditions, the Mo K‐edge XANES spectra showed a transition from a mixture of α‐MoO3_{3} and Fe2_{2}(MoO4_{4})3_{3} towards only Fe2_{2}(MoO4_{4})3_{3}. XRD and Raman spectroscopy also showed disappearance of the α‐MoO3 phase with time on stream. The results evidenced that the α‐MoO3 component evaporated completely, while the Fe2_{2}(MoO4_{4})3_{3} component remained stable. This was linked to a decrease in catalytic activity. Further studies unraveled that the rate of α‐MoO3_{3} evaporation increased with increasing MeOH concentration, decreasing O2_{2} concentration and increasing temperature. The simultaneous measurements of catalytic activity and spectroscopy allowed to derive a structure‐activity relationship showing that α‐MoO3_{3} evaporation needs to be prevented to optimize MoO3_{3}‐based catalysts for selective oxidation of methanol

    The challenges of renewed independence: The Baltic states since 1991

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    This article offers a comparative assessment of how successfully Estonia, Latvia, and Lithuania have coped with the challenges of renewed independence since 1991, focusing on various aspects of political, economic, and social development. In the post-communist context the Baltic states have clearly outpaced other former Soviet republics and also performed reasonably well in comparison to the countries of Eastern Europe. The convergence of the Baltic experience, which began already in the early 20th century, has continued in the recent past as well, as the three states have adopted a number of similar approaches in domestic politics, the search for security, and economic policy. They also face a number of similar unsolved problems, including considerable political alienation, tensions in relations with Russia, socioeconomic disparity, and demographic challenges. The most important difference in the issues confronting the Baltic states today continues to be the large non-Baltic, mainly Russian presence in Estonia and Latvia, a result of Soviet-era policies. How to effect the meaningful integration of a multiethnic society remains a continuing challenge in these two countries. In contrast, population shifts under Soviet rule never became massive in Lithuania, and ethnic relations are a minor issue there today

    Nanotitanium dioxide toxicity in mouse lung is reduced in sanding dust from paint

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    <p>Abstract</p> <p>Background</p> <p>Little is known of how the toxicity of nanoparticles is affected by the incorporation in complex matrices. We compared the toxic effects of the titanium dioxide nanoparticle UV-Titan L181 (NanoTiO<sub>2</sub>), pure or embedded in a paint matrix. We also compared the effects of the same paint with and without NanoTiO<sub>2</sub>.</p> <p>Methods</p> <p>Mice received a single intratracheal instillation of 18, 54 and 162 μg of NanoTiO<sub>2 </sub>or 54, 162 and 486 μg of the sanding dust from paint with and without NanoTiO<sub>2</sub>. DNA damage in broncheoalveolar lavage cells and liver, lung inflammation and liver histology were evaluated 1, 3 and 28 days after intratracheal instillation. Printex 90 was included as positive control.</p> <p>Results</p> <p>There was no additive effect of adding NanoTiO<sub>2 </sub>to paints: Therefore the toxicity of NanoTiO<sub>2 </sub>was reduced by inclusion into a paint matrix. NanoTiO<sub>2 </sub>induced inflammation in mice with severity similar to Printex 90. The inflammatory response of NanoTiO<sub>2 </sub>and Printex 90 correlated with the instilled surface area. None of the materials, except of Printex 90, induced DNA damage in lung lining fluid cells. The highest dose of NanoTiO<sub>2 </sub>caused DNA damage in hepatic tissue 1 day after intratracheal instillation. Exposure of mice to the dust from paints with and without TiO<sub>2 </sub>was not associated with hepatic histopathological changes. Exposure to NanoTiO<sub>2 </sub>or to Printex 90 caused slight histopathological changes in the liver in some of the mice at different time points.</p> <p>Conclusions</p> <p>Pulmonary inflammation and DNA damage and hepatic histopathology were not changed in mice instilled with sanding dust from NanoTiO<sub>2 </sub>paint compared to paint without NanoTiO<sub>2</sub>. However, pure NanoTiO<sub>2 </sub>caused greater inflammation than NanoTiO<sub>2 </sub>embedded in the paint matrix.</p

    Replicability of nitrogen recommendations from ramped calibration strips in winter wheat

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    Ramped calibration strips have been suggested as a way for grain producers to determine nitrogen needs more accurately. The strips use incrementally increasing levels of nitrogen and enable producers to conduct an experiment in each field to determine nitrogen needs. This study determines whether predictions from the program Ramp Analyzer 1.2 are replicable in Oklahoma hard red winter wheat (Triticum aestivum). Predictions are derived from 36 individual strips from on-farm experiments—two pairs of adjacent strips at each of nine winter wheat fields in Canadian County, OK. The two pairs of strips within each field were between 120 and 155 m apart. Each strip was analyzed three times during the 2006–2007 growing season. Nitrogen recommendations from Ramp Analyzer 1.2 are not correlated even for strips that were placed side by side, and recommendations from strips in the same field show no more homogeneity than randomly selected strips throughout the county. The results indicate that ramped calibration strips are unlikely to produce accurate nitrogen requirement predictions at any spatial scale, whether at the county level or for subsections of a single field. In contrast, a procedure that uses only measures from the plot with no nitrogen and the plot with the highest level of nitrogen applied does show replicability. Thus, improvements in the ramped calibration strip technology are needed if it is to become viable
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