655 research outputs found

    Improved Farmer\u27s Capasity Model of Private Forest Management: Studies in Ranggang Village, South Kalimantan

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    Farmer\u27s capacity is one of the important factors that determine the success of private forest management. However, the farmer\u27s capacity level in several places is still low so that potentially to inhibiting successful of private forests management practices. This study aims to analyze the factors that affect farmer\u27s capacity level of private forests management practices, and to formulate improved farmer\u27s capacity model of private forests management in Ranggang Village, South Kalimantan. The data was analyzed by Structural Equation Model (SEM) with the help of SmartPls 2.0 M3. Results showed (1) learning experience level directly affect to farmer\u27s capacity while farmer\u27s characteristics, external support, social and cultural environment supporting, the role of extension, and information availability indirectly affect to farmer\u27s capacity of private forests management in Ranggang Village, and (2) improved farmer\u27s capacity model can be done by improving the farmer\u27s learning experience through intensive, scheduled, and suistainable education, training and extension with stakeholders support

    Einfluss der Verarbeitungstechnologie und Werkstoffzusammensetzung auf die Struktur-Eigenschafts-Beziehungen von thermoplastischen Nanoverbundwerkstoffen

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    Die Einarbeitung von nanoskaligen FĂŒllstoffen zur Steigerung von polymeren Eigenschaftsprofilen ist sehr viel versprechend und stĂ¶ĂŸt daher heutzutage sowohl in der Forschung als auch in der Industrie auf großes Interesse. Bedingt durch ausgeprĂ€gte OberflĂ€chen und hohe AnziehungskrĂ€fte, liegen Nanopartikel allerdings nicht singulĂ€r sondern als PartikelanhĂ€ufungen, so genannten Agglomeraten oder Aggregaten, vor. Zur Erzielung der gewĂŒnschten Materialverbesserungen gilt es, diese aufzuspalten und homogen in der polymeren Matrix zu verteilen. Bei thermoplastischen Kunststoffen ist die gleichlĂ€ufige Doppelschneckenextrusion eines der gĂ€ngigsten Verfahren zur Einarbeitung von Additiven und FĂŒllstoffen. Aus diesem Grund war es Ziel dieser Arbeit, mittels dieses Verfahrens verbesserte Verbundwerkstoffe mit Polyamid 66- und Polyetheretherketon-Matrix, durch Einarbeitung von nanoskaligem Titandioxid (15 und 300 nm), zu generieren. In einem ersten Schritt wurden die verfahrenstechnischen Parameter, wie Drehzahl und Durchsatz, sowie die ProzessfĂŒhrung und damit deren Einfluss auf die Materialeigenschaften beleuchtet. Der spezifische Energieeintrag ist ausschlaggebend zur Deagglomeration der Nanopartikel. Dieser zeigte leichte AbhĂ€ngigkeiten von der Drehzahl und dem Durchsatz und verursachte bei der Einarbeitung der Partikel keine wesentlichen Unterschiede in der Aufspaltung der Partikel sowie gar keine in den resultierenden mechanischen Eigenschaften. Die ProzessfĂŒhrung wurde unterteilt in Mehrfach- und Einfachextrusion. Die Herstellung eines hochgefĂŒllten Masterbatches, dessen mehrfaches Extrudieren und anschließendes VerdĂŒnnen, fĂŒhrte zu einer sehr guten Deagglomeration und stark verbesserten Materialeigenschaften. Mittels Simulation des Extrusionsprozesses konnte festgestellt werden, dass das Vorhandensein von ungeschmolzenem Granulat in der Verfahrenszone zu einer Schmelze/Nanopartikel/ Feststoffreibung fĂŒhrt, die die Ursache fĂŒr eine sehr gute Aufspaltung der Partikel zu sein scheint. Durch Modifikation des Extrusionsprozesses erreichte die Einfachextrusion annĂ€hernd den Grad an Deagglomeration bei Mehrfachextrusion, wobei die Materialien bei letzterem Verfahren die besten Eigenschaftsprofile aufwiesen. In einem zweiten Schritt wurde ein Vergleich der EinflĂŒsse von unterschiedlichen PartikelgrĂ¶ĂŸen und –gehalten auf die polymeren Matrizes vollzogen. Die 15 nm Partikel zeigten signifikant bessere mechanische Ergebnisse auf als die 300 nm Partikel, und die Wirkungsweise des 15 nm Partikels auf Polyetheretherketon war stĂ€rker als auf Polyamid 66. Es konnten Steigerungen in Steifigkeit, Festigkeit und ZĂ€higkeit erzielt werden. Rasterelektronenmikroskopische Aufnahmen bestĂ€tigten diese Ergebnisse. Eine Berechnung der Plan-Selbstkosten von einem Kilogramm PEEK-Nanoverbundwerkstoff im Vergleich zu einem Kilogramm unverstĂ€rktem PEEK verdeutlichte, dass ein Material kreiert wurde, welches deutlich verbesserte Eigenschaften bei gleichem Preis aufweist. Zusammenfassend konnte in dieser Arbeit ein tieferes VerstĂ€ndnis des Extrusionsvorganges zur Herstellung von kostengĂŒnstigen und verbesserten Thermoplasten durch das Einbringen von Nanopartikeln gewonnen werden

    Descriptive statistics for each variable.

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    The impact of the digital economy (DE) on urban environmental quality (EQ) is a critical aspect of China’s economic development. This study investigates the impact of DI on urban EQ using the data from prefecture-level cities spanning the period from 2011 to 2021 and updates some disparate conclusions of related studies. It is discovered that a non-linear correlation exists between DE and urban EQ. Currently, DE can effectively improve local city EQ. This conclusion remains valid even after robustness tests and endogeneity treatment. The impact of DE on improving EQ can be classified as the impact of technological innovation, industrial upgrading, resource allocation, infrastructure construction, environmental governance, and changes in public lifestyle. Heterogeneity analysis reveals that the influence of DE is particularly pronounced in cities located in central and eastern regions of China, those with higher levels of administrative management, resource-based urban areas, and those with more stringent environmental regulations.</div

    Dehydrogenation Selectivity of Ethanol on Close-Packed Transition Metal Surfaces: A Computational Study of Monometallic, Pd/Au, and Rh/Au Catalysts

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    Ethanol (EtOH) decomposition has been widely studied in recent years. However, the initial dehydrogenation selectivity on catalytic surfaces, which plays a crucial role in EtOH partial oxidation and steam reforming, is not well understood. Here, density functional theory (DFT) was used to calculate the initial dehydrogenation selectivities of EtOH on monometallic and X/Au (X = Pd and Rh) close-packed surfaces. The energy for the initial bond scissions of O–H and α- and ÎČ-C–H were calculated on each surface. The binding energy of EtOH is found to be a good reactivity descriptor for the scission of O–H and ÎČ-C–H bonds, while the binding energy of CH<sub>3</sub>CHOH is a good reaction descriptor for α-C–H bond scission. The scaling relationships between the activation energy barriers and binding energies on Pd/Au and Rh/Au surface alloys are significantly different from those of monometallic surfaces. Additionally, the specific atomic ensembles on the Pd/Au and Rh/Au surfaces have different initial dehydrogenation selectivities of EtOH. Our calculated scaling relationships were used to construct contour plots that provide predictive trends for the selectivity of the initial EtOH dehydrogenation. We conclude that the presence of specific atomic ensembles on the surface of alloy catalysts can efficiently control the reaction products of EtOH dehydrogenation

    Highly Selective Detection of Polycyclic Aromatic Hydrocarbons Using Multifunctional Magnetic–Luminescent Molecularly Imprinted Polymers

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    A facile method is presented for the selective luminescence detection of trace polycyclic aromatic hydrocarbons (PAHs) based on a combination of the specific recognition of molecularly imprinted polymers (MIPs) and magnetic separation (MS). Multifunctional magnetic–luminescent MIP nanocomposites were fabricated via a one-pot emulsion strategy using polystyrene-co-methacrylic acid copolymer, hydrophobic Fe<sub>3</sub>O<sub>4</sub> nanoparticles and luminescent LaVO<sub>4</sub>:Eu<sup>3+</sup> nanoparticles as building blocks with a phenanthrene template. The resulting nanocomposites can be employed in a simple method for the luminescence detection of phenanthrene. Furthermore, magnetic separation of the nanocomposites from the target mixture prior to luminescence detection of phenanthrene affords significantly enhanced selectivity and sensitivity, with a 3σ limit of detection (LOD) as low as 3.64 ng/mL. Milk samples spiked with phenanthrene (5.0 ÎŒg/mL) were assayed via this method and recoveries ranging from 97.11 to 101.9% were obtained, showing that our strategy is potentially applicable for the preconcentration, recovering, and monitoring of trace PAHs in complex mixtures

    Quantifying the Reduction Intensity of Handaxes with 3D Technology: A Pilot Study on Handaxes in the Danjiangkou Reservoir Region, Central China

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    <div><p>This paper presents an approach to analyzing the reduction intensity of handaxes with the aid of 3D scanning technology. Two quantitative reduction indices, the Scar Density Index (SDI) and the Flaked Area Index (FAI), are applied to handaxes from the third terrace of the Danjiangkou Reservoir Region (DRR), central China, dated to the Middle Pleistocene. The results show that most of the DRR handaxes in this sample show moderate reduction, which also reflects a least-effort reduction strategy and a generally short use-life for these tools. Detailed examination of the DRR handaxes by sector reveals that the tips generally show the most reduction, while the bases show the least shaping, with cortex often preserved on the base to facilitate handling. While western Acheulean assemblages in this regard are variable, there are many examples of handaxes of varying age with trimming of the bases. We also found no significant differences in the levels of reduction between the two main raw materials, quartz phyllite and trachyte. However, the type of blank used (large flakes versus cobbles) and the type of shaping (bifacial, partly bifacial and unifacial) do play a significant role in the reduction intensity of the DRR handaxes. Finally, a small number of handaxes from the younger (the early Late Pleistocene) second terrace of the DRR was compared with those from the third terrace. The results indicate that there is no technological change in the reduction intensity through time in these two DRR terraces.</p></div

    Olfactory Genes Lie in a Mutational Hot Spot

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    <p>Substitution rates of the olfactory genes in the central region of human Chromosome 11. The substitution rate of ancestral repeat sequences is higher in the region where the olfactory genes lie.</p

    Distribution of Normalized Substitution Rates

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    <p>Histogram of substitution rates based on 14,790 orthologous mouse and human genes (black curve). The rate distribution has significantly more genes at high and low rates than the expected Normal distribution (red curve). This bias toward high and low rates remains even when rates are corrected for human base composition (green curve).</p

    Correlation analysis between volume and SDI.

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    <p>Correlation analysis between volume and SDI.</p

    Raw materials and blank types of the DRR handaxes from T3.

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    <p><sup>a</sup> Because of the highly weathered surface of one trachyte handaxe made on a cobble, its scar number is indeterminable. Thus, 15 trachyte handaxes were used for comparison. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135613#pone.0135613.s001" target="_blank">S1 Table</a> for raw data.</p><p>Flake blanks include bipolar flakes.</p
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