3,882 research outputs found

    Triphen­yl(tetra­hydro­furan)­aluminium(III)

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    In the title compound, [Al(C6H5)3(C4H8O)], the Al atom has a distorted tetra­hedral geometry. The C—Al—C angles range from 113.25 (7) to 116.27 (8)°, much larger than the O—Al—C angles, which range from 103.39 (7) to 103.90 (6)°. The tetra­hydro­furan ring adopts an envelope conformation. The crystal packing is stabilized by C—H⋯π inter­actions

    Resonance properties of a closed rotating rectangular basin subject to space- and time-dependent wind forcing

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    We present an idealised process-based model to study the possibly resonant response of closed basins subject to periodic wind forcing. Two solution methods are adopted: a collocation technique (valid for arbitrary rotation) and an analytical expansion (assuming weak rotation). The spectral response, as obtained from our model, displays resonance peaks, which we explain by linking them to the spatial pattern of the wind forcing, the along-wind and cross-wind basin dimensions as well as the influence of rotation. Increasing bottom friction lowers the peaks. Finally, we illustrate how the spectral response is reflected in the time-dependent set-up due to a single wind even

    Patches in a side-by-side configuration: a description of the flow and deposition fields

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    In the last few decades, a lot of research attention has been paid to flow-vegetation interactions. Starting with the description of the flow field around uniform macrophyte stands, research has evolved more recently to the description of flow fields around individual, distinct patches. However, in the field, vegetation patches almost never occur in isolation. As such, patches will influence each other during their development and interacting, complex flow fields can be expected. In this study, two emergent patches of the same diameter (D = 22 cm) and a solid volume fraction of 10% were placed in a side-by-side configuration in a lab flume. The patches were built as an array of wooden cylinders, and the distance between the patches (gap width Delta) was varied between Delta = 0 and 14 cm. Flow measurements were performed by a 3D Vectrino Velocimeter (Nortek AS) at mid-depth of the flow. Deposition experiments of suspended solids were performed for selected gap widths. Directly behind each patch, the wake evolved in a manner identical to that of a single, isolated patch. On the centerline between the patches, the maximum velocity U-max was found to be independent of the gap width Delta. However, the length over which this maximum velocity persists, the potential core L-j, increased linearly as the gap width increased. After the merging of the wakes, the centerline velocity reaches a minimum value U-min. The minimum centerline velocity decreased in magnitude as the gap width decreased. The velocity pattern within the wake is reflected in the deposition patterns. An erosion zone occurs on the centerline between the patches, where the velocity is elevated. Deposition occurs in the low velocity zones directly behind each patch and also downstream of the patches, along the centerline between the patches at the point of local velocity minimum. This downstream deposition zone, a result of the interaction of neighbouring patch wakes, may facilitate the establishment of new vegetation, which may eventually inhibit flow between the upstream patches and facilitate patch merger

    A new representation of emotion in affective computing

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    In the recent years, increasing attention has been paid to the area of affective computing, which deals with the complex phenomenon of human emotion. Therefore, a model for describing, structuring, and categorizing emotional states of users is required. The dimensional emotion theory is one of widely used theoretical foundations for categorization of emotions. According to the dimensional theory, emotional states are projected to the affective space, which has two dimensions: valence and arousal. In order to navigate in the affective space, Cartesian coordinate system is used, where emotion quality is defined by combination of valence and arousal. In this paper, we propose another representation of the affective space with polar coordinate system. The key advantages of such a representation include (1) capability to account not only for emotion quality, but also for emotion intensity, (2) reasonable explanation of the location of neutral emotion in the affective space, and (3) straightforward interpretation of the meaning of an emotional state (quality defined by angle and intensity defined by distance from the origin). Although in our experiment most of the induced motions can be differentiated with polar coordinate system, further investigation is still needed to find out either Cartesian or polar coordinates system represents affective space better in practice

    Study on the Support-Anchor Combined Technique to Control Perilous Rock at the Source of Avalanche by Fracture Mechanics

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    As a kind of existing and potential geological disaster at source of avalanche on cliffs or steep slopes, perilous rock has developed in the western area of China widely and it poses a serious threat to highways, railways, pipelines, cities, and mining for a long time. More than ten years of engineering experience have shown the necessity and importance to pay our attention to the avalanche sources in active collapse mitigation. The support - anchor combined technique is devoted to the active hazard mitigation measures of perilous rock. This paper introduces fracture mechanics to investigate the design procedure of the support - anchor combined technique. To obtain reasonable design parameters of the technique, both stability assessment criterion and three safety classes of protection engineering for perilous rock is proposed, further, stable analysis methods for various types of perilous rock are established by using fracture mechanics. Abiding by the idea that to improve stability coefficient to a higher level, the support force of structure and the anchorage force of anchorbolt from the support - anchor combined technique are introduced into stability analysis methods established above, which can estimate the section dimension of support subunit and the amount of anchorbolt of the technique. Engineering applications of the technique in thousands of protection engineering have identified the remarkable effectiveness.Більш ніж десять років інженерного досвіду в західній частині Китаю показали необхідність і важливість уваги до джерел лавин з метою активного зменшення катастроф. Для вимірювання активного зменшення ризику від небезпечних грунтів розроблена об‘єднана методика «опора-анкер». У роботі застосована механіка руйнування для дослідження процедури створення розрахункової схеми об‘єднаної методики «опора-анкер». Для отримання коректних параметрів схеми запропоновано критерій оцінки стійкості і три класи безпеки інженерного захисту для небезпечних грунтів. Далі на основі механіки руйнування розвинуті стійкі методи аналізу для різних типів небезпечних грунтів. На основі ідеї про покращення коефіцієнтів стійкості до вищого рівня в методи аналізу стійкості введено силу опори в конструкції та силу анкера для анкерного болта в опорі з об‘єднаної методики «опора-анкер». Це дозволяє оцінити в застосованій методиці розмір секції в опорі і кількість анкерних болтів. Інженерні застосування запропонованої методики показали суттєву ефективність у тисячах випадків інженерного захисту

    Certain subclasses of multivalent functions defined by new multiplier transformations

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    In the present paper the new multiplier transformations \mathrm{{\mathcal{J}% }}_{p}^{\delta }(\lambda ,\mu ,l) (\delta ,l\geq 0,\;\lambda \geq \mu \geq 0;\;p\in \mathrm{% }%\mathbb{N} )} of multivalent functions is defined. Making use of the operator Jpδ(λ,μ,l),\mathrm{% {\mathcal{J}}}_{p}^{\delta }(\lambda ,\mu ,l), two new subclasses Pλ,μ,lδ(A,B;σ,p)\mathcal{% P}_{\lambda ,\mu ,l}^{\delta }(A,B;\sigma ,p) and P~λ,μ,lδ(A,B;σ,p)\widetilde{\mathcal{P}}% _{\lambda ,\mu ,l}^{\delta }(A,B;\sigma ,p)\textbf{\ }of multivalent analytic functions are introduced and investigated in the open unit disk. Some interesting relations and characteristics such as inclusion relationships, neighborhoods, partial sums, some applications of fractional calculus and quasi-convolution properties of functions belonging to each of these subclasses Pλ,μ,lδ(A,B;σ,p)\mathcal{P}_{\lambda ,\mu ,l}^{\delta }(A,B;\sigma ,p) and P~λ,μ,lδ(A,B;σ,p)\widetilde{\mathcal{P}}_{\lambda ,\mu ,l}^{\delta }(A,B;\sigma ,p) are investigated. Relevant connections of the definitions and results presented in this paper with those obtained in several earlier works on the subject are also pointed out

    Observation of Two New N* Peaks in J/psi -> ppinˉp pi^- \bar n and pˉπ+n\bar p\pi^+n Decays

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    The πN\pi N system in decays of J/ψNˉNπJ/\psi\to\bar NN\pi is limited to be isospin 1/2 by isospin conservation. This provides a big advantage in studying NπNN^*\to \pi N compared with πN\pi N and γN\gamma N experiments which mix isospin 1/2 and 3/2 for the πN\pi N system. Using 58 million J/ψJ/\psi decays collected with the Beijing Electron Positron Collider, more than 100 thousand J/ψpπnˉ+c.c.J/\psi \to p \pi^- \bar n + c.c. events are obtained. Besides two well known NN^* peaks at 1500 MeV and 1670 MeV, there are two new, clear NN^* peaks in the pπp\pi invariant mass spectrum around 1360 MeV and 2030 MeV. They are the first direct observation of the N(1440)N^*(1440) peak and a long-sought "missing" NN^* peak above 2 GeV in the πN\pi N invariant mass spectrum. A simple Breit-Wigner fit gives the mass and width for the N(1440)N^*(1440) peak as 1358±6±161358\pm 6 \pm 16 MeV and 179±26±50179\pm 26\pm 50 MeV, and for the new NN^* peak above 2 GeV as 2068±340+152068\pm 3^{+15}_{-40} MeV and 165±14±40165\pm 14\pm 40 MeV, respectively

    Transcriptome analysis of hepatic gene expression and DNA methylation in methionine- and betaine-supplemented geese (Anser cygnoides domesticus)

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    Dietary methionine (Met) restriction produces a coordinated series of transcriptional responses in the liver that limits growth performance and amino acid metabolism. Methyl donor supplementation with betaine (Bet) may protect against this disturbance and affect the molecular basis of gene regulation. However, a lack of genetic information remains an obstacle to understand the mechanisms underlying the relationship between Met and Bet supplementation and its effects on genetic mechanisms. The goal of this study was to identify the effects of dietary supplementation of Met and Bet on growth performance, transcriptomic gene expression, and epigenetic mechanisms in geese on a Met-deficient diet. One hundred and fifty 21-day-old healthy male Yangzhou geese of similar body weight were randomly distributed into 3 groups with 5 replicates per treatment and 10 geese per replicate: Met-deficient diet (Control), Control+1.2 g/kg of Met (Met), and Control+0.6 g/kg of Bet (Bet). All geese had free access to the diet and water throughout rearing. Our results indicated that supplementation of 1.2 g/kg of Met in Met-deficient feed increased growth performance and plasma homocysteine (HCY) levels, indicating increased transsulfuration flux in the liver. Supplementation of 0.6 g/kg Bet had no apparent sparing effect on Met needs for growth performance in growing geese. The expression of many genes critical for Met metabolism is increased in Met supplementation group. In the Bet-supplemented group, genes involved in energy production and conversion were up-regulated. Dietary supplementation with Bet and Met also altered DNA methylation. We observed changes in the methylation of the LOC106032502 promoter and corresponding changes in mRNA expression. In conclusion, Met and Bet supplementation in geese affects the transcriptional regulatory network and alters the hepatic DNA methylation of LOC106032502
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