81 research outputs found
What Marketing Measures Can Organic Apple and Pear Growers Take to Increase Their Receipts?
Crop Production/Industries, Marketing,
Implication of Cotton Price Behavior on Market Integration
The cotton market in China is highly interactive with international markets, especially, the US market. The prices in these two markets can reveal important market relations. Investigating the data of futures prices from the New York Board of Trade (NYBOT) and the Zhengzhou Commodity Exchange (CZCE) using several time series methods, we find a long-run cointegration relationship between these I(1) series. Furthermore, a bi-directional Granger Causality between these two futures markets is detected with Generalized Autoregressive Conditional Heteroskedasticity (GARCH) error specifications. We also find the relationship is impacted by the Chinese exchange rate policy change in the 2005.cotton futures prices, cointegration, granger causality test, AR-GARCH., Agricultural Finance,
Trade and Integration of the US and China’s Cotton Markets
The cotton market in China is highly interactive with international markets, especially, the US market. The prices in these two markets can reveal important market relations. Investigating the data of futures prices from the New York Board of Trade (NYBOT) and the Zhengzhou Commodity Exchange (CZCE) using several time series methods, we find a long-run cointegration relationship between these I(1) series. Furthermore, a bi-directional Granger Causality between these two futures markets is detected with Generalized Autoregressive Conditional Heteroskedasticity (GARCH) error specifications. We also find the relationship is impacted by the Chinese exchange rate policy change in the 2005.cotton futures prices, cointegration, granger causality test, AR-GARCH, Agricultural Finance, Demand and Price Analysis, International Relations/Trade,
Diffusional transfer function for the scanning electrical mobility spectrometer (SEMS)
The scanning electrical mobility spectrometer (SEMS), or scanning mobility particle sizer (SMPS), uses the differential mobility analyzer (DMA) operated in scanning mode to measure particle size distribution rapidly. To obtain the actual size distribution, the real-time transfer function (transmission efficiency of particles of different mobilities) is necessary, which has previously been investigated with numerical simulations or semi-analytical calculations. We present here a rigorous derivation of the diffusional DMA transfer function for an increasing-voltage scan based on analytically resolving particle trajectories between the instrument inlet and the outlet. This requires a 2D integration in the inlet and outlet space over the contour plot of the particle mobility distribution that can successfully transmit through the scanning DMA. For the first time, we show that the up-scan DMA transfer function for non-diffusive particles is trapezoidal (instead of triangular). The key parameter that determines the shape of the scanning DMA transfer function is the ratio of the characteristic scanning time to the average residence time, which yields the same transfer function as that for the static DMA when the ratio gets sufficiently large. The effect of particle diffusion is included via an extended outlet. The dimensionless equations for the trajectories and the method presented here can be generalized to the column DMA of any geometry
Deformable Object Tracking with Gated Fusion
The tracking-by-detection framework receives growing attentions through the
integration with the Convolutional Neural Networks (CNNs). Existing
tracking-by-detection based methods, however, fail to track objects with severe
appearance variations. This is because the traditional convolutional operation
is performed on fixed grids, and thus may not be able to find the correct
response while the object is changing pose or under varying environmental
conditions. In this paper, we propose a deformable convolution layer to enrich
the target appearance representations in the tracking-by-detection framework.
We aim to capture the target appearance variations via deformable convolution,
which adaptively enhances its original features. In addition, we also propose a
gated fusion scheme to control how the variations captured by the deformable
convolution affect the original appearance. The enriched feature representation
through deformable convolution facilitates the discrimination of the CNN
classifier on the target object and background. Extensive experiments on the
standard benchmarks show that the proposed tracker performs favorably against
state-of-the-art methods
Coupling Filter-Based Thermal Desorption Chemical Ionization Mass Spectrometry with Liquid Chromatography/Electrospray Ionization Mass Spectrometry for Molecular Analysis of Secondary Organic Aerosol
Filter-based thermal desorption (F-TD) techniques, such as the filter inlet for gases and aerosols, are widely employed to investigate the molecular composition and physicochemical properties of secondary organic aerosol (SOA). Here, we introduce an enhanced capability of F-TD through the combination of a customized F-TD inlet with chemical ionization mass spectrometry (CIMS) and ultraperformance liquid chromatography/electrospray ionization mass spectrometry (UPLC/ESI-MS). The utility of F-TD/CIMS + UPLC/ESI-MS is demonstrated by application to α-pinene ozonolysis SOA for which increased filter aerosol mass loading is shown to slow the evaporation rates of deposited compounds. Evidence for oligomer decomposition producing multimode F-TD/CIMS thermograms is provided by the measurement of the mass fraction remaining of monomeric and dimeric α-pinene oxidation products on the filter via UPLC/ESI-MS. In situ evaporation of aerosol particles suggests that α-pinene-derived hydroperoxides are thermally labile; thus, analysis of particle-phase (hydro)peroxides via F-TD may not be appropriate. A synthesized pinene-derived dimer ester (C₂₀H₃₂O₅) is found to be thermally stable up to 200 °C, whereas particle-phase dimers (C₁₉H₃₀O₅) are observed to form during F-TD analysis via thermally induced condensation of synthesized pinene-derived alcohols and diacids. The complementary F-TD/CIMS + UPLC/ESI-MS method offers previously inaccessible insight into the molecular composition and thermal desorption behavior of SOA that both clarifies and expands on analysis via traditional F-TD techniques
Coupling Filter-Based Thermal Desorption Chemical Ionization Mass Spectrometry with Liquid Chromatography/Electrospray Ionization Mass Spectrometry for Molecular Analysis of Secondary Organic Aerosol
Filter-based thermal desorption (F-TD) techniques, such as the filter inlet for gases and aerosols, are widely employed to investigate the molecular composition and physicochemical properties of secondary organic aerosol (SOA). Here, we introduce an enhanced capability of F-TD through the combination of a customized F-TD inlet with chemical ionization mass spectrometry (CIMS) and ultraperformance liquid chromatography/electrospray ionization mass spectrometry (UPLC/ESI-MS). The utility of F-TD/CIMS + UPLC/ESI-MS is demonstrated by application to α-pinene ozonolysis SOA for which increased filter aerosol mass loading is shown to slow the evaporation rates of deposited compounds. Evidence for oligomer decomposition producing multimode F-TD/CIMS thermograms is provided by the measurement of the mass fraction remaining of monomeric and dimeric α-pinene oxidation products on the filter via UPLC/ESI-MS. In situ evaporation of aerosol particles suggests that α-pinene-derived hydroperoxides are thermally labile; thus, analysis of particle-phase (hydro)peroxides via F-TD may not be appropriate. A synthesized pinene-derived dimer ester (C₂₀H₃₂O₅) is found to be thermally stable up to 200 °C, whereas particle-phase dimers (C₁₉H₃₀O₅) are observed to form during F-TD analysis via thermally induced condensation of synthesized pinene-derived alcohols and diacids. The complementary F-TD/CIMS + UPLC/ESI-MS method offers previously inaccessible insight into the molecular composition and thermal desorption behavior of SOA that both clarifies and expands on analysis via traditional F-TD techniques
A Note on Flow Behavior in Axially-Dispersed Plug Flow Reactors with Step Input of Tracer
Atmospheric chemistry studies are frequently conducted in flow reactors, such as the potential aerosol mass (PAM) reactor. To characterize the flow condition in such a reactor, an axially-dispersed plug flow reactor (AD-PFR) model has been applied to explain the observed residence time distribution (RTD). Compared with the traditional RTD analysis that directly fits the observed data from a pulse input or differentiates the data points from a step input, we introduce here a direct method to retrieve the axial diffusivity in an AD-PFR model by fitting an analytical formula to the rising profile of the tracer at the beginning of the experiment (the transition data before the reactor reaches steady state). This method can be readily used to determine the flow conditions inside an AD-PFR
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