An insight on the mechanism of efficient leaching of vanadium from vanadium shale induced by microwave-generated hot spots

Microwave heating can rapidly and uniformly raise the temperature and accelerate the reaction rate.In this paper,microwave heating was used to improve the acid leaching,and the mechanism was investigated via microscopic morphology analysis and numerical simulation by COMSOL Multiphysics software.The effects of the microwave power,leaching temperature,CaF_(2) dosage,H_(2)SO_(4) concentration,and leaching time on the vanadium recovery were investigated.A vanadium recovery of 80.66%is obtained at a microwave power of 550 W,leaching temperature of 95℃,CaF_(2) dosage of 5wt%,H_(2)SO_(4) concentration of 20vol%,and leaching time of 2.5 h.Compared with conventional leaching technology,the vanadium recovery increases by 6.18%,and the leaching time shortens by 79.17%.More obvious pulverization of shale particles and delamination of mica minerals happen in the microwave-assisted leaching process.Numerical simulation results show that the temperature of vanadium shales increases with an increase in electric field(E-field).The distributions of E-field and temperature among vanadium shale particles are relatively uniform,except for the higher content at the contact position of the particles.The analysis results of scaleup experiments and leaching experiments indicate high-temperature hot spots in the process of microwave-assisted leaching,and the local high temperature destroys the mineral structure and accelerates the reaction rate.

Detection of spatial hot spots and variation for the neon flying squid Ommastrephes bartramii resources in the northwest Pacific Ocean

With the increasing effects of global climate change and fishing activities,the spatial distribution of the neon flying squid(Ommastrephes bartramii) is changing in the traditional fishing ground of 150°-160°E and 38°-45°N in the northwest Pacific Ocean.This research aims to identify the spatial hot and cold spots(i.e.spatial clusters) of O.bartramii to reveal its spatial structure using commercial fishery data from2007 to 2010 collected by Chinese mainland squid-j igging fleets.A relatively strongly-clustered distribution for O.bartramii was observed using an exploratory spatial data analysis(ESDA) method.The results show two hot spots and one cold spot in 2007 while only one hot and one cold spots were identified each year from2008 to 2010.The hot and cold spots in 2007 occupied 8.2%and 5.6%of the study area,respectively;these percentages for hot and cold spot areas were 5.8%and 3.1%in 2008,10.2%and 2.9%in 2009,and 16.4%and 11.9%in 2010,respectively.Nearly half(>45%) of the squid from 2007 to 2009 reported by Chinese fleets were caught in hot spot areas while this percentage reached its peak at 68.8%in 2010,indicating that the hot spot areas are central fishing grounds.A further change analysis shows the area centered at156°E/43.5°N was persistent as a hot spot over the whole period from 2007 to 2010.Furthermore,the hot spots were mainly identified in areas with sea surface temperature(SST) in the range of 15-20℃ around warm Kuroshio Currents as well as with the chlorophyll-a(chl-a) concentration above 0.3 mg/m^3.The outcome of this research improves our understanding of spatiotemporal hotspots and its variation for O.bartramii and is useful for sustainable exploitation,assessment,and management of this squid.

SYSTEMATIC AND DYNAMIC PROPERTIES OF CASTING HOT SPOT

The variation of casting hot spot with proceeding of solidification andcomponents of casting-mold system is studied by the technique of numerical simulation ofsolidification. The result shows that the thickest part of casting is not exactly the last part ofsolidification in the casting, while the last part of solidification is not exactly casting hot spotat the early stage of solidification. The location, size, shape and number of casting hot spotchange with geomitric, physical and technological factors of the casting-mold system such asthickness of the casting secondary wall and with the passage of time in the course of thesolidification. The former is known as the systematic property of hot spot and the latter, dynamicproperty. Only when the properties of hot spot are grasped completely and accurately, can it be fedmore effectively. By doing so, not only sound castings can be obtained, but also riser efficiencycan be improved.

The Hot Spots in Cereal Rusts and Powdery Mildew Research

Cereal crops, including wheat, barley, oats, rye, etc., are the major sources of calories and proteins for most of the people in the world as well as in China. Cereal rusts and powdery mildews are very important diseases occurred on the cereal crops, which caused yield losses at 5-10% in general and even more than 30% while severe epidemics occurred. In recent years, with the global climate change, change of cultivation system and evolution of the pathogens, the world is facing great challenges caused by cereal diseases.

一种消除hot spot现象的LED背光设计

随着高亮度LED晶片、导光板成型技术、光学薄膜(反射膜、散射膜、增亮膜)等制作技术的发展,加上不断创新的LED背光模组光学系统设计,以及LED背光市场的巨大需求,大大推动了LED背光技术水平不断向前发展。这里设计了一种消除hot spot现象的背光设计。结果可知:达到设计效果的改进关键仅是在导光板的入光面上贴上一条有微棱镜结构的膜片,从而使入射至导光板的光束角度变大,达到良好的均匀光效果。让增加相邻LED间距而不出现hot spot现象成为可能,这一研究对于消除hot spot所带来的均匀性过差问题具有一定的意义。

HOT SPOT RELIEF WITH EMBEDDED BEAM FOR CDMA SYSTEMS IN HAPS

This paper proposes a novel micro/macro beam coverage scheme used in High Altitude Platform System (HAPS) Code Division Multiple Access (CDMA) systems. A relief of traffic burden in hot spot areas is achieved by embedding micro-beams into the macro-beams at the hot spot locations, together with appropriate power ratio control and user ratio control. The simulation results show that the hot spot problem can be relieved efficiently with the presented configuration, and a higher and more stable system capacity is expectable despite the variation of user distribution.

Hot Spot in Materials with Structural Defects under High Shear Loading Rates

The response of three-dimensional sample of Al, containing vacancy complex, under shear loading was simulated. The molecular dynamics method was used and interaction between atoms was described on the base of pseudopotential theory Solitary waves were generated in the sample under mechanical loading. Their interaction with the vacancy complexes was shown to be able to initiate hot spot in that local region of the complexes. Some parameters of the hot spot as well as solitary waves were calculated. The initiation of the hot spot is accompanied with sufficient local structural relaxation.

STUDY ON LOCATION OF HOT SPOT AT TUBE WALL FOR FIRED CYLINDRICAL FURNACE COMBUSTION

Based on the analysis of heat radiation intensity from flame, a new mathematical model ofthe tube-wall temperatmp of heated tubes is developed by taking down-fired, upright-tube cylindricalfurnace for example. The proposed mathematical model can be employed to indicate both the positionand size of the hot spot at fire-facing wall of heated tube of combustion chamber, and is characteristicof simplicity and efficiency If coupled with thermoelectric couple or infrared viewer, the presentedlocation method of combustion hot spot can offer engineers very valuable proposal to keep furnacerunning more safely The same is true for any other type of tubular furnaces.

The ”Hot Spots” Conjecture on Homogeneous Hierarchical Gaskets

In this paper, using spectral decimation, we prove that the "hot spots" conjecture holds on a class of homogeneous hierarchical gaskets introduced by Hambly,i.e., every eigenfunction of the second-smallest eigenvalue of the Neumann Laplacian(introduced by Kigami) attains its maximum and minimum on the boundary.

Identifying hot spots of long-duration extreme climate events in the northwest arid region of China and implications for glaciers and runoff

China’s Northwest Arid Region(NAR),with dry and cold climate conditions and glaciers widely developed in the high mountains,provides vital water resources for Asia.The consecutive cold,warm,dry and wet days have much higher impacts on the water cycle process in this region than extreme temperature and precipitation events with short durations but high intensities.Parametric and nonparametric trend analysis methods widely used in climatology and hydrology are employed to identify the temporal and spatial features of the changes in the consecutive cold,warm,dry and wet days in the NAR based on China’s 0.5°×0.5°meteorological grid datasets of daily temperature and precipitation from 1961 to 2018.This study found that(1)the consecutive cold days(Cold Spell Duration Indicator,CSDI),and the consecutive dry days(CDD)decreased,while the consecutive warm days(Warm Spell Duration Indicator,WSDI),and the consecutive wet days(CWD)increased from 1961 to 2018,(2)and the eastern Kunlun Mountains were the hot spots where all of these consecutive climate indices changed significantly,(3)and the changes in these consecutive climate indices were highly correlated with the rise in the Global Mean Land/Ocean Temperature Index.The results indicated that winters tended to warmer and dryer and summer became hotter and wetter during 1961–2018 in the NAR under the global warming,which can lead to the sustained glacier retreat and the increase in summer runoff in this region,and the eastern Kunlun Mountains are the area where could face high risks of water scarcity and floods if the changes in these climate indices continue in the future.Given the vulnerability of the socio-economic systems in the NAR to a water shortage and floods,it is most crucial to improve the strategies of water resources management,disaster prevention and risk management for this region under climate change.

Scalable and Accessible Crash Hot Spot Detection for Traffic Law Enforcement

Law enforcement agencies have begun utilizing traffic and crash data to improve traffic law enforcement delivery. However, many agencies often do not have the resources or expertise to harness fully the benefits this data offers. A free to use, scalable traffic crash hot spot detection tool was developed to aid law enforcement agency decision makers, statewide to the local municipality level. The tool was developed to identify crash hot spots algorithmically with a range of customizable parameters based on location, date and time, and crash factors, enabling quick, dynamic queries. These capabilities provide the ability for law enforcement agencies to conduct “what if” analyses and make data-driven allocation decisions, placing officer resources where they are most needed. The two-step algorithm first identifies potential hot spots based on crash density and then ranks each hot spot using a standardized z-score measure of relative significance. To test the viability of the tool, a pilot was conducted identifying 27 hot spots across Wisconsin where targeted enforcement was then deployed. Despite officer skepticism, results from the pilot found officers at sites targeted for speeding and seatbelt violations were nearly twice as likely to initiate traffic stops compared to non-targeted hot spots. Empirical Bayes before-and-after crash analyses found fatal and injury crashes reduced significantly by nearly 11% during the months with targeted enforcement, while property damage crashes and total crashes were unchanged. Overall, the results show the algorithm can identify hotspots where, coupled with targeted enforcement, traffic safety improvements can be made.

Effects of Preheat on the Thermodynamics of the ICF Hot Spot

We determine the dependence of key inertial confinement fusion （ICF） hot spot properties on the deuterium-tritium （DT） fuel adiabat accomplished by addition of heat to the cold shell. Our main result is to observe that variation of this parameter reduces the simulation to experiment discrepancy in several experimentally inferred quantities. Simulations are continued from capsule only l D simulations using the Lawrence Livermore National Laboratory ICF code, HYDRA. The continuations employ the high energy density physics （HEDP） University of Chicago code, FLASH, and a hydro only code, FronTier, modified with a radiation equation of state （EOS） model. Hot spot densities, burn-weighted ion temperatures and pressures show a decreasing trend, while the hot spot radius shows an increasing trend in response to added heat to the cold shell. Instantaneous quantities are assessed at the time of maximum neutron production within each simulation.

Numerical Simulation of Hot Spot Growth in Detonation with Regard to the Turbulent Mechanism of Energy Transfer

The paper presents the results of numerical modeling of hot spot growth process in detonation with account for turbulent mixing. The performed investigation has shown that large-scale HE （High explosives） particles mix up and split down to smaller sizes in the result of shock wave impact, instability development on the HE-EP （Explosion product） interface and vortex flow; at these sizes, due to the developed surface of the HE-EP contact, HE has enough time to get heated （energy transfer from EP）, and the decomposition reaction effectively continues. Numerical modeling make the calculation of the hot spot growth rate （about 100-200 m/s） possible. This has proved the hypothesis saying that at mechanical material transport the turbulence in the reaction zone plays an important role and it must be taken into account in the detonation theory.

Determination and Analysis of Hot Spot Areas of Deforestation Using Remote Sensing and Geographic Information System Techniques. Case Study: State Sinaloa, México

The main objective of this research is to analyze deforestation in State Sinaloa during the period 1990-2014. For this, “deforestationhot-spot areas” were identified, by crossing maps of 1993 and 2011 at a 1:250,000 scale with knowledge from environmental and forest experts from each region. Landsat images from 1990 and 2014 and Terra Amazon System were used to monitor the most critical hot spot area, applying Linear Spectral Mixture Analysis and Image Segmentation Ground Product. In order to generate the map deforestation year zero (1990), every segmented object of ground product was visually assigned to “Forest” and “No-Forest” categories. Therefore, gains and losses were interpreted for the map deforestation year one (2014). Those products were validated with the help of experts on the subject and applying a confusion matrix. Results obtained indicated that the highest forest loss was located in North-Central Sinaloa (hot spot area number two) by establishing the average annual rate of deforestation of 4741.90 ha/year with an average rate of 0.60%, being higher than the national average rate (0.37%). This result affects directlyon calculation of carbonfluxes at nationallevel.

The hot spots in bovine mastitis research

The 2017 International Bovine Mastitis Conference ＆ The National Mastitis Council Regional in China was successfully held in Beijing on August 25-27, 2017. Nearly 650 participants from more than eight countries （regions） and international organizations attended this conference. The conference provided an communication platform for international counterparts, and the content was closely related to all aspects of dairy cow health, including dairy mastitis pathogens, diagnose, therapeutics, management, residue, bacterial resistance and milk safety. Here we are pleased to have the opportunity to organize a special focus and provide the most updated knowledge of the given topics.

Some Hot Spots in the Study of Chinese Drugs in the 21st Century

Mankind has entered the 21st century of high speed development in science and e-conomics. Owing to the alteration of disease modes in the new century, the greatly elevated quality of human life and the arrival of aged society, the modes of medicine have obviously changed from the treatment mode

改善侧导光LED背光Hot Spot现象的导光板设计

就改善侧导光LED背光Hot Spot现象,文章提出了一种解决办法:在导光板入光侧对应LED的位置进行处理,让其形成一个非球面的凹面,可以使LED发出的光发散,从而减轻或消除Hot Spot现象。

Research Hot Spots of Black Peanut

Taking the research papers on black peanut in National Knowledge Infrastructure(CNKI)as data sources,we determine the research hot spots on black peanut using word frequency analysis,and analyze the main research directions that change over the years.The results show that the relevant researches on black peanut are mainly concentrated in six themes(study of varieties,physiological property,cultivation management,development prospects,relationship with agriculture,and molecular level);varieties,physiology,cultivation and other aspects are the focus of current research hot spots;the researches on selection and breeding of variety and various physiological and ecological mechanisms,still need a breakthrough.

Health Hot Spots: Mapping Hospital Costs and Social Determinants of Health

Accountable care organizations (ACOs) and hospitals are facing additional requirements and financial rewards for improving population health. Therefore, ACOs and hospitals will need tools to understand the relationship between their patients and social determinants and health. We demonstrate the use of hot spotting for identifying geographical sources of high hospital costs and examining links between social determinants of health and these high-cost areas, known as hot spots. In 2012, using hospital data, we generated maps of inpatient costs from 2011 throughout New Haven and within an example neighborhood, Dixwell. We defined hot spots as addresses where costs were in the top 25%. We also overlaid data on concerns and assets in the community. Finally, we calculated the number of concerns and assets that fall within the 250 and 500 ft radii of the defined hot spots. We found that 34 addresses in Dixwell accounted for 70% of total costs for Dixwell. Hot spotting is a straightforward, approachable, and easily understood method for ACOs and hospitals to begin to address population health.