The impact of the urban heat island (UHI) effect on environmental and regional climate has been receiving wide attention in recent decades. Taiwan, especially Taipei (located in northern Taiwan), is ...experiencing a significant UHI effect due to its high population density and the uniqueness of the geographic structure. In order to evaluate the impacts of urbanization and UHI effect over northern Taiwan, a next generation mesoscale model, Weather Research and Forecasting (WRF) model coupled with the Noah land surface model and Urban Canopy model (UCM), was used to study this issue.
By using the WRF–Noah–UCM model, it has significantly improved our simulation results for the prediction of the UHI effect, boundary layer development, and land sea breeze. Observations of weather stations and Lidar showed that the near surface air temperature was nearly 34–35
°C and the boundary layer height was nearly 1500
m around noon in Taipei on 17 June 2006. Around midnight, the air temperature ranged from 26 to 28
°C. Our model can predict well for boundary layer development during the daytime and the UHI effect in northern Taiwan. Sensitivity tests indicate that the anthropogenic heat (AH) plays an important role for the boundary layer development and UHI intensity in the Taipei area, especially during nighttime and early morning. When we increase AH by 100
W
m
−2 in the model, the average surface temperature could increase nearly 0.3
°C in Taipei. Furthermore, we found the UHI effect also has a significant impact on land sea circulation. It could enhance the sea breeze in the daytime and weaken the land breeze during the nighttime and hence had a significant impact on the air pollution diffusion in northern Taiwan.
Gastric cancer is one of the most common malignant cancers, with poor prognosis and high mortality rates worldwide. Therefore, development of an effective therapeutic method without side effects is ...an urgent need. It has been reported that cationic antimicrobial peptides can selectively bind to negatively charged prokaryotic and cancer cell membranes and exert cytotoxicity without causing severe drug resistance. In the current study, we prepared a series of peptide fragments derived from bovine lactoferrin and evaluated their anticancer potency toward the gastric cancer cell line AGS. Cell viability assay revealed that a 25-AA peptide fragment, lactoferricin B25 (LFcinB25), exhibited the most potent anticancer capability against AGS cells. Lactoferricin B25 selectively inhibited AGS cell growth in a dose-dependent manner, exhibiting a half-maximal inhibitory concentration (IC50) value of 64μM. Flow cytometry showed a notable increment of the sub-G1 populations of the cell cycle, indicating the induction of apoptosis by LFcinB25. Western blot analysis further revealed that upon LFcinB25 treatment for 2 to 6h, apoptosis-related caspases-3, 7, 8, 9, and poly(ADP-ribose) polymerase (PARP) were cleaved and activated, whereas autophagy-related LC3-II and beclin-1 were concomitantly increased. Thus, both apoptosis and autophagy are involved in the early stage of LFcinB25-induced cell death of AGS cells. However, upon treatment with LFcinB25 for 12 to 24h, LC3-II began to decrease, whereas cleaved beclin-1 increased in a time-dependent manner, suggesting that consecutive activation of caspases cleaved beclin-1 to inhibit autophagy, thus enhancing apoptosis at the final stage. These findings provide support for future application of LFcinB25 as a potential therapeutic agent for gastric cancer.
•A local form of second law of thermodynamics demonstrates fundamental physics of superfluidity at so-called boundary of second law.•On the boundary of second law, any motion is non-dissipative. ...Super momentum has no shear strength and super energy flow has no thermal resistance.•At resonance, super momentum motion implies pressure waves propagating at the speed of first sound. At resonance, super energy flow is represented by temperature waves propagating at the speed of second sound.•A formula of second sound depends solely on thermos-mechanical properties has been validated against experimental data on the velocity of S waves.•Theory of hydrodynamics in solids is demonstrated by using the experimental data of transient heat transfer due to friction and interface thermal conductance.
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In solids, hydrodynamics have been observed in both amorphous and crystalline materials under a wide range of conditions. However, its fundamental physics is still unclear. Recent advancements in nanotechnology, biomedicine and electronics have reinvigorated interest in research on hydrodynamic solids. Here, we established the hydrodynamic transport in solids from solid mechanics. We showed that isentropically, a solid becomes superfluid locally in space and time when subjected to periodic motions, and at resonance, the first and second sound are generated. We validated the speed of the second sound against the velocity of S waves, and the agreement is satisfactory. From the concept of the boundary of the second law, we established the boundary conditions for the governing equations of the supersolid and obtained the transient and steady-state solutions of the supersolid. The theory agrees well with the measured flash temperature of the bulk metallic glass (BMG), which elucidates the physics why thermocouples do not measure flash temperature accurately. The finding shall lead to the review of the adequacy of instrumentation where temperature measurement is critical. The validation of the steady-state solution was carried out by comparison to the interfacial thermal conductance (ITC) on solid-solid interfaces. The first dataset has metal-metal interfaces with variable pressures, and the second dataset has metal-dielectric interfaces with variable temperatures, whose ITC differs by 4 orders of magnitude. We discuss the physics of this difference. We believe that the theory of hydrodynamics in solids provides insights for a vast number of disciplines and that the methods and solutions can help practitioners.
The unprecedented ability of computations to probe atomic-level details of catalytic systems holds immense promise for the fundamentals-based bottom-up design of novel heterogeneous catalysts, which ...are at the heart of the chemical and energy sectors of industry. Here, we critically analyze recent advances in computational heterogeneous catalysis. First, we will survey the progress in electronic structure methods and atomistic catalyst models employed, which have enabled the catalysis community to build increasingly intricate, realistic, and accurate models of the active sites of supported transition-metal catalysts. We then review developments in microkinetic modeling, specifically mean-field microkinetic models and kinetic Monte Carlo simulations, which bridge the gap between nanoscale computational insights and macroscale experimental kinetics data with increasing fidelity. We finally review the advancements in theoretical methods for accelerating catalyst design and discovery. Throughout the review, we provide ample examples of applications, discuss remaining challenges, and provide our outlook for the near future.
Heat transfer at speed of sound Chen, W.
International journal of heat and mass transfer,
October 2021, 2021-10-00, 20211001, Letnik:
177
Journal Article
Recenzirano
•A local form of second law of thermodynamics demonstrates fundamental physics of superfluidity at so-called boundary of second law.•On the boundary of second law, any motion is non-dissipative. ...Super momentum flow has no viscosity and super energy flow has no thermal resistance.•At resonance, super momentum flow implies pressure waves propagating at the speed of first sound. At resonance, super energy flow is represented by temperature waves propagating at the speed of second sound.•A formula of second sound depends solely on thermos-mechanical properties has been derived, which is validated against experimental data on temperature discontinuity and interface thermal resistance.•Theory of heat transfer at the speed of sound is demonstrated by using the experimental data of interface thermal conductivity.
In this manuscript, heat transfer at the speed of sound has been established by introduction of a local form of the second law of thermodynamics and conservation laws and validated by experimental data. When the local form, excess entropy, equals to zero, the boundary of the second law is reached and superfluidity and sound are observed; otherwise, motion is dissipative. First and second sound are generated in super momentum and super energy flows, respectively. From differential equations of conservation, wave equations, speed of sound, and impedance and thermal resistance of first and second sound are derived. Dependent on conventional thermomechanical properties, a formula of second sound is obtained, which has not been found in public domain. The theory and formulas of sonic heat transfer and interface thermal resistance and conductance are derived according to the principles of acoustics first time. We validated the speed of second sound and formulas for for heat transfer at sound speed by experimental data. Overall, calculations from formulas capture key characteristics of the experimental data satisfactorily. At lower temperature, the predicted temperature jump at the interface matches data well. Predictions of interface thermal conductance demonstrate all important characteristics and some of them match data well. Temperature discontinuity at an interface is the result of acoustic effect of second sound of two materials. Differential equations of conservation of both regular and super states can be utilized to solve a complex problem computationally.
The Asteroid Terrestrial impact Last Alert System (ATLAS) system consists of two 0.5 m Schmidt telescopes with cameras covering 29 square degrees at plate scale of 1.86 arcsec per pixel. Working in ...tandem, the telescopes routinely survey the whole sky visible from Hawaii (above δ > − 50 ° ) every two nights, exposing four times per night, typically reaching o < 19 magnitude per exposure when the moon is illuminated and c < 19.5 magnitude per exposure in dark skies. Construction is underway of two further units to be sited in Chile and South Africa which will result in an all-sky daily cadence from 2021. Initially designed for detecting potentially hazardous near earth objects, the ATLAS data enable a range of astrophysical time domain science. To extract transients from the data stream requires a computing system to process the data, assimilate detections in time and space and associate them with known astrophysical sources. Here we describe the hardware and software infrastructure to produce a stream of clean, real, astrophysical transients in real time. This involves machine learning and boosted decision tree algorithms to identify extragalactic and Galactic transients. Typically we detect 10-15 supernova candidates per night which we immediately announce publicly. The ATLAS discoveries not only enable rapid follow-up of interesting sources but will provide complete statistical samples within the local volume of 100 Mpc. A simple comparison of the detected supernova rate within 100 Mpc, with no corrections for completeness, is already significantly higher (factor 1.5 to 2) than the current accepted rates.
The atomic dispersing of metal atoms supported on an optimal substrate exhibits an ideal strategy for maximizing metal utilization for catalysis, which is particularly significant for exploiting new ...catalysts with low cost and high catalytic efficiency. The dramatic development of atomic metal catalysts, including single atom catalysts (SACs), double atoms catalysts (DACs), and triple atoms catalysts (TACs), has spawned two remarkable platforms: (1) bridging homogeneous catalysts and heterogeneous catalysts; (2) linking theoretical calculations and experimental results. In this review, recent syntheses, characterizations, and applications of SACs, DACs, and TACs are highlighted through a focus on various applied substrates. We extensively discuss the synthetic strategies of successfully achieving SACs, DACs, and TACs. Moreover, the opportunities and challenges in developing SACs, DACs, and TACs are pointed out, together with the prospects for the development of atomic catalysis.
SACs, DACs, and TACs, heterogeneous catalysts with the advantages of homogeneous catalysts, are ideal models for exploring catalytic mechanisms and further designing catalysts.
This study unveils the time–space transforms underlying anomalous diffusion process. Based on this finding, we present the two hypotheses concerning the effect of fractal time–space fabric on ...physical behaviors and accordingly derive fractional quantum relationships between energy and frequency, momentum and wavenumber which further give rise to fractional Schrödinger equation. As an alternative modeling approach to the standard fractional derivatives, we introduce the concept of the Hausdorff derivative underlying the Hausdorff dimensions of metric spacetime. And in terms of the proposed hypotheses, the Hausdorff derivative is used to derive a linear anomalous transport–diffusion equation underlying anomalous diffusion process. Its Green’s function solution turn out to be a stretched Gaussian distribution and is compared with that from the Richardson’s turbulence diffusion equation.
Aims
The aim of the study was to survey rhizobial biogeography and to inoculate soybean with selected rhizobia in China to enhance symbiotic nitrogen fixation (SNF).
Methods and Results
Biogeography, ...genetic diversity and phylogeny of soybean rhizobia were surveyed. Inocula were prepared and applied to soybean. Results showed that Bradyrhizobium elkanii and Ensifer fredii were widely distributed in acid and alkaline soils respectively. Available iron was detected as the first determinant for distribution of the two rhizobia and the soybean varieties did not greatly affect the rhizobial compatibility. Geographical latitude and precipitation in June were the main geographical and climatic factors affecting the rhizobial distribution. Inoculation with selected rhizobia increased the nodule number, fresh weight, occupation ratio, seed protein content and soybean yields.
Conclusions
Selection and application of effective soybean rhizobia across China according to biogeography were clarified to promote the SNF, thereby improving soybean yield.
Significance and Impact of the Study
Rhizobial diversity and biogeography were evaluated systematically in six sites across China. Available iron and soil pH are found to be the most important determinants for the distribution of soybean rhizobia. Inoculation to soybean enhances SNF, positively correlating to the increase in soybean yield and seed protein content.
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