•A downscaling-disaggregation study was firstly attempted over Singapore Island.•A combined GLM, KNN and MuDRain was proved to work well.•Rainfall data at sub-daily timescales under climate change ...are examined.
A systematic downscaling-disaggregation study was conducted over Singapore Island, with an aim to generate high spatial and temporal resolution rainfall data under future climate-change conditions. The study consisted of two major components. The first part was to perform an inter-comparison of various alternatives of downscaling and disaggregation methods based on observed data. This included (i) single-site generalized linear model (GLM) plus K-nearest neighbor (KNN) (S-G-K) vs. multisite GLM (M-G) for spatial downscaling, (ii) HYETOS vs. KNN for single-site disaggregation, and (iii) KNN vs. MuDRain (Multivariate Rainfall Disaggregation tool) for multisite disaggregation. The results revealed that, for multisite downscaling, M-G performs better than S-G-K in covering the observed data with a lower RMSE value; for single-site disaggregation, KNN could better keep the basic statistics (i.e. standard deviation, lag-1 autocorrelation and probability of wet hour) than HYETOS; for multisite disaggregation, MuDRain outperformed KNN in fitting interstation correlations. In the second part of the study, an integrated downscaling-disaggregation framework based on M-G, KNN, and MuDRain was used to generate hourly rainfall at multiple sites. The results indicated that the downscaled and disaggregated rainfall data based on multiple ensembles from HadCM3 for the period from 1980 to 2010 could well cover the observed mean rainfall amount and extreme data, and also reasonably keep the spatial correlations both at daily and hourly timescales. The framework was also used to project future rainfall conditions under HadCM3 SRES A2 and B2 scenarios. It was indicated that the annual rainfall amount could reduce up to 5% at the end of this century, but the rainfall of wet season and extreme hourly rainfall could notably increase.
Climate change is expected to lead to more frequent and intensive flooding problems for watersheds in the south part of China. This study presented a coupled Long Ashton Research Station Weather ...Generator (LARS-WG) and Semidistributed Land Use–Based Runoff Processes (SLURP) approach for flood frequency analysis and applied it to the Heshui watershed, China. LARS-WG, as a weather generator, was used to offer 46 sets of climate data from seven general circulation models (GCMs) under various emission scenarios (i.e., A1B, B1, and A2) over near-term and future periods (i.e.,T₁, 2011–30;T₂, 2046–65; andT₃, 2080–99). SLURP is a continuous, spatially distributed hydrological model that uses parameters from physiographic data to simulate the hydrological cycle from precipitation to runoff. Flood frequency analysis based on Pearson type III distributions was followed to analyze statistics of annual peaks. The final results (from ensembles of multimodels and multiscenarios) indicated that the magnitudes of a 200-yr return flood forT₁,T₂, andT₃ would increase by 5.23%, 4.08%, and 12.92%, respectively, in comparison to the baseline level; those under the most extreme condition (i.e., worst scenario) would be 25.18%, 31.00%, and 44.46%, respectively. Various GCMs and emission scenarios suggested different results. But the ECHAM5/Max Planck Institute OceanModel was found to give a more worrying intensification of flood risks and the Commonwealth Scientific and Industrial Research Organisation Mark, version 3.0, and the Community Climate System Model, version 3, were relatively conservative. The study results were useful in helping gain insight into the flood risks and its uncertainty under future climate change conditions for the Heshui watershed, and the proposed methodology is also applicable to many other watersheds in Southeast Asia with similar climatic conditions.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A novel method to determine the total hydrogen density and, accordingly, a precise plasma temperature in a lowly ionized hydrogen plasma is described. The key to the method is to analyze the energy ...loss of swift heavy ions interacting with the respective bound and free electrons of the plasma. A slowly developing and lowly ionized hydrogen theta-pinch plasma is prepared. A Boltzmann plot of the hydrogen Balmer series and the Stark broadening of the H_{β} line preliminarily defines the plasma with a free electron density of (1.9±0.1)×10^{16} cm^{-3} and a free electron temperature of 0.8-1.3 eV. The temperature uncertainty results in a wide hydrogen density, ranging from 2.3×10^{16} to 7.8×10^{18} cm^{-3}. A 108 MHz pulsed beam of ^{48}Ca^{10+} with a velocity of 3.652 MeV/u is used as a probe to measure the total energy loss of the beam ions. Subtracting the calculated energy loss due to free electrons, the energy loss due to bound electrons is obtained, which linearly depends on the bound electron density. The total hydrogen density is thus determined as (1.9±0.7)×10^{17} cm^{-3}, and the free electron temperature can be precisely derived as 1.01±0.04 eV. This method should prove useful in many studies, e.g., inertial confinement fusion or warm dense matter.
Dynamic headspace sampling (DHS) coupled with gas chromatography–mass spectrometry and olfactometry (GC–MS–O) analysis have been applied for the determination of the characteristic volatile profile ...of propolis with the aim to differentiate the propolis from different regions of China. Acids, esters, alcohols, terpenes, aromatics represented the most abundant compounds in propolis among the ninety-nine volatile components identified by comparing with mass spectra and retention indices (RI) or from literature. In addition, principal component analysis (PCA) based on the data of DHS–GC–MS and electronic nose was used to study and obtain the important volatile compounds contributed to the differentiation of the propolis samples from different regions. Furthermore, a total of 28 odor-active compounds were detected and characterized by the trained panel of judges in the sniffing port of GC–O by using detection frequency analysis (DFA). In conclusion, GC–MS analysis and electronic nose combining with PCA could successfully distinguish the twelve representative raw propolis samples from 4 different geographical regions of China. The samples have been assigned to four large groups in accordance with their vegetal sampling location and we also have observed the volatile compounds resulting in the odor differentiation.
► DHS/GC–MS was applied for the determination of the volatile profile of propolis. ► The identification of the geographical origin of propolis was carried out. ► The propolis samples were discriminated by GC–MS coupled with PCA method. ► The propolis samples were discriminated by electronic nose coupled with PCA. ► GC–O was used to identify aroma-active components of propolis.
To improve the convergence of multiple-site weather generators (SWGs) based on the brute force algorithm (MBFA), a genetic algorithm (GA) is proposed to search the overall optimal correlation matrix. ...Precipitation series from weather generators are used as input to the hydrological model, the soil and water assessment tool (SWAT), to generate runoff over the Red Deer watershed, Canada for further runoff analysis. The results indicate that the SWAT model using SWG-generated data accurately represents the mean monthly streamflow for most of the months. The multi-site generators were capable of better representing the monthly streamflow variability, which was notably underestimated by the single-site version. In terms of extreme flows, the proposed method reproduced the observed extreme flow with smaller bias than MBFA, while the single-site generator significantly underestimated the annual maximum flows due to its poor capability in addressing partial precipitation correlations.
The exclusive process e+e−→ΛΛ¯, with Λ→pπ− and Λ¯→p¯π+, has been studied at s=2.396 GeV for measurement of the timelike Λ electric and magnetic form factors, GE and GM. A data sample, corresponding ...to an integrated luminosity of 66.9 pb−1, was collected with the BESIII detector for this purpose. A multidimensional analysis with a complete decomposition of the spin structure of the reaction enables a determination of the modulus of the ratio R=|GE/GM| and, for the first time for any baryon, the relative phase ΔΦ=ΦE−ΦM. The resulting values are R=0.96±0.14(stat)±0.02(syst) and ΔΦ=37°±12°(stat)±6°(syst), respectively. These are obtained using the recently established and most precise value of the asymmetry parameter αΛ=0.750±0.010 measured by BESIII. In addition, the cross section is measured with unprecedented precision to be σ=118.7±5.3(stat)±5.1(syst) pb, which corresponds to an effective form factor of |G|=0.123±0.003(stat)±0.003(syst). The contribution from two-photon exchange is found to be negligible. Our result enables the first complete determination of baryon timelike electromagnetic form factors.
Silver nanoparticles are widely used due to their superior optical, electrical, catalytic and antimicrobial properties. Recent development of nanostructure silver production incorporated with fiber ...makes it possible to utilize its excellent physical and chemical properties in the field of textiles. This work focuses on the surface functionalization of polyester fiber with nanostructured silver film by magnetron sputtering to widen its applications. The surface characterizations are investigated by employing a scanning electron microscope. The results show that the surface functionalization of silver-coated polyester fiber is highly versatile, and silver-coated polyester fabrics possess excellent protection from ultraviolet radiation, exhibit excellent hydrophobicity (contact angle
=
132.2°) and good antibacterial performance. This study demonstrates that surface treatment which uses silver nanoparticles by magnetron sputtering is a promising method for achieving multifunctional fabrics.
Leakage and spill of petroleum hydrocarbons from underground storage tanks and pipelines have posed significant threats to groundwater resources across many petroleum-contaminated sites. Remediation ...of these sites is essential for protecting the soil and groundwater resources and reducing risks to local communities. Although many efforts have been made, effective design and management of various remediation systems are still challenging to practitioners. In recent years, the subsurface simulation model has been combined with techniques of optimization to address important problems of contaminated site management. The combined simulation-optimization system accounts for the complex behavior of the subsurface system and identifies the best management strategy under consideration of the management objectives and constraints. During the past decades, a large number of studies were conducted to simulate contaminant flow and transport in the subsurface and seek cost-effective remediation designs. This paper gives a comprehensive review on recent developments, advancements, challenges, and barriers associated with simulation and optimization techniques in supporting process control of petroleum waste management and site remediation. A number of related methodologies and applications were examined. Perspectives of effective site management were investigated, demonstrating many demanding areas for enhanced research efforts, which include issues of data availability and reliability, concerns in uncertainty, necessity of post-modeling analysis, and usefulness of development of process control techniques.
To delineate the activities of decorin and biglycan in the progression of post-traumatic osteoarthritis (PTOA).
Three-month-old inducible biglycan (BgniKO) and decorin/biglycan compound (Dcn/BgniKO) ...knockout mice were subjected to the destabilization of the medial meniscus (DMM) surgery to induce PTOA. The OA phenotype was evaluated by assessing joint structure and sulfated glycosaminoglycan (sGAG) staining via histology, surface collagen fibril nanostructure and calcium content via scanning electron microscopy, tissue modulus via atomic force microscopy-nanoindentation, as well as subchondral bone structure and meniscus ossification via micro-computed tomography. Outcomes were compared with previous findings in the inducible decorin (DcniKO) knockout mice.
In the DMM model, BgniKO mice developed similar degree of OA as the control (0.44 -0.18 1.05 difference in modified Mankin score), different from the more severe OA phenotype observed in DcniKO mice (1.38 0.91 1.85 difference). Dcn/BgniKO mice exhibited similar histological OA phenotype as DcniKO mice (1.51 0.97 2.04 difference vs control), including aggravated loss of sGAGs, salient surface fibrillation and formation of osteophyte. Meanwhile, Dcn/BgniKO mice showed further cartilage thinning than DcniKO mice, resulting in the exposure of underlying calcified tissues and aberrantly high surface modulus. BgniKO and Dcn/BgniKO mice developed altered subchondral trabecular bone structure in both Sham and DMM groups, while DcniKO and control mice did not.
In PTOA, decorin plays a more crucial role than biglycan in regulating cartilage degeneration, while biglycan is more important in regulating subchondral bone structure. The two have distinct activities and modest synergy in the pathogenesis of PTOA.
Abstract
A theoretical study on the interplay of frustrated skyrmion and magnons should reveal new physics and future experiment designs. In this study, we investigate the magnon-driven dynamics of ...frustrated skyrmion in synthetic antiferromagnets based on micromagnetic simulations, focusing on the effect of skyrmion helicity oscillation. The oscillation speed and Hall angle of the frustrated skyrmion depending on the magnon intensity and damping constant are simulated, which demonstrates that the skyrmion helicity oscillation effectively suppresses Hall motion. The elastic scattering theory reveals that the helicity oscillation affects the scattering cross-section of injected magnons, which in turn effectively modulates the skyrmion Hall motion. This study provides a comprehensive understanding of magnon-skyrmion scattering in frustrated magnets, thus benefiting future spintronic and magnonic applications.
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