scholarly journals Hot Spots in the Weak Detonation Problem and Special Relativity

Axioms ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 311
Author(s):  
Satyanad Kichenassamy
Keyword(s):  
Hot Spots ◽  
Blow Up ◽  
Hot Spot ◽  
Gaseous Mixture ◽  
Approximate Solutions ◽  
Four Dimensions ◽  
Present Solution ◽  
Full Neighborhood ◽  
Three Space ◽  
The Impact

Problem statement: The initiation of a detonation in an explosive gaseous mixture in the high activation energy regime, in three space dimensions, typically leads to the formation of a singularity at one point, the “hot spot”. It would be suitable to have a description of the physical quantities in a full neighborhood of the hot spot. Results of this paper: (1) To achieve this, it is necessary to replace the blow-up time, or time when the hot spot first occurs, by the blow-up surface in four dimensions, which is the set of all hot spots for a class of observers related to one another by a Lorentz transformation. (2) A local general solution of the nonlinear system of PDE modeling fluid flow and chemistry, with a given blow-up surface, is obtained by the method of Fuchsian reduction. Advantages of this solution: (i) Earlier approximate solutions are contained in it, but the domain of validity of the present solution is larger; (ii) it provides a signature for this type of ignition mechanism; (iii) quantities that remain bounded at the hot spot may be determined, so that, in principle, this model may be tested against measurements; (iv) solutions with any number of hot spots may be constructed. The impact on numerical computation is also discussed.

Twenty-First-Century Climate Change Hot Spots in the Light of a Weakening Sun

2020 ◽  
Vol 33 (9) ◽  
pp. 3431-3447
Author(s):  
Tobias Spiegl ◽  
Ulrike Langematz
Keyword(s):  
Climate Change ◽  
Hot Spots ◽  
Climate Model ◽  
Hot Spot ◽  
Ghg Emissions ◽  
Arctic Sea Ice ◽  
First Century ◽  
Vulnerability To Climate Change ◽  
Twenty First Century ◽  
The Impact

AbstractSatellite measurements over the last three decades show a gradual decrease in solar output, which can be indicative as a precursor to a modern grand solar minimum (GSM). Using a chemistry–climate model, this study investigates the potential of two GSM scenarios with different magnitude to counteract the climate change by projected anthropogenic greenhouse gas (GHG) emissions through the twenty-first century. To identify regions showing enhanced vulnerability to climate change (hot spots) and to estimate their response to a possible modern GSM, a multidimensional metric is applied that accounts for—in addition to changes in mean quantities—seasonal changes in the variability and occurrence of extreme events. We find that a future GSM in the middle of the twenty-first century would temporarily mitigate the global mean impact of anthropogenic climate change by 10%–23% depending on the GSM scenario. A future GSM would, however, not be able to stop anthropogenic global warming. For the GHG-only scenario, our hot-spot analysis suggests that the midlatitudes show a response to rising GHGs below global average, while in the tropics, climate change hot spots with more frequent extreme hot seasons will develop during the twenty-first century. A GSM would reduce the climate change warming in all regions. The GHG-induced warming in Arctic winter would be dampened in a GSM due to the impact of reduced solar irradiance on Arctic sea ice. However, even an extreme GSM could only mitigate a fraction of the tropical hot-spot pattern (up to 24%) in the long term.

Mining technology hot spots in the 3D printing industry for technology strategic planning based on MRCAI

2020 ◽  
Vol 39 (5) ◽  
pp. 7135-7149
Author(s):  
Shugang Li ◽  
Lirong Zhu ◽  
Boyi Zhu ◽  
Ru Wang ◽  
Lingling Zheng ◽  
...  
Keyword(s):  
3D Printing ◽  
Strategic Planning ◽  
Hot Spots ◽  
Prediction Accuracy ◽  
Citation Count ◽  
Printing Industry ◽  
Generalization Performance ◽  
Four Dimensions ◽  
The One ◽  
The Impact

3D printing is the important part of the emerging industry, and the accurate prediction of technology hot spots (THS) in the 3D printing industry is crucial for the strategic technology planning. The patents of the THS are always in the minority and have outlier characteristics, so the existing single and rigid models cannot accurately and robustly predict the THS. In order to make up for the shortcomings of the existing research, this study proposes a model for robust composite attraction indicator (MRCAI), which avoids the impact of outlier patents on prediction accuracy depending on not only extracting the patent attraction indicators (AIs) but also constructing the robust composite attraction indicator (CAI) according to the rough consensus of predicted results of CAIs with high generalization. Specifically, firstly, this study selects the patent AIs from the four dimensions of the attraction: technology group attraction, state attraction, enterprise attraction and inventor attraction. Secondly, in order to completely describe the attraction features of patent, AIs are directly and indirectly integrated into CAIs. Thirdly, we reduce the influence of outlier patents on prediction accuracy from two aspects: on the one hand, we initially select the CAIs with good generalization performance based on the prediction error fluctuation range. On the other hand, we build the robust CAIs by calculating the consensus of CAIs with high generalization performance based on the rough set. Fourthly, the 3D printing industry technology attention matrix is constructed to map the effective technology strategic planning based on predicted patent backward citation count by MRCAI in the short, medium and long term. Finally, the experimental results on 3D printing patent data show that MRCAI can effectively improve the efficiency in dealing with samples with outlier patents and has strong flexibility and robustness in predicting the THS in 3D printing industry.

scholarly journals Effect of Loads on Temperature Distribution Characteristics of Oil-Immersed Transformer Winding

2021 ◽  
Author(s):  
Zhengang Zhao ◽  
Zhangnan Jiang ◽  
Yang Li ◽  
Chuan Li ◽  
Dacheng Zhang
Keyword(s):  
Temperature Distribution ◽  
Hot Spots ◽  
Hot Spot ◽  
Transformer Oil ◽  
Distribution Characteristics ◽  
Thermal Circuit ◽  
Transformer Winding ◽  
Overload Capacity ◽  
The Impact ◽  
Spot Temperature

The temperature of the hot-spots on windings is a crucial factor that can limit the overload capacity of the transformer. Few studies consider the impact of the load on the hot-spot when studying the hot-spot temperature and its location. In this paper, a thermal circuit model based on the thermoelectric analogy method is built to simulate the transformer winding and transformer oil temperature distribution. The hot-spot temperature and its location under different loads are qualitatively analyzed, and the hot-spot location is analyzed and compared to the experimental results. The results show that the hot-spot position on the winding under the rated power appears at 85.88% of the winding height, and the hot-spot position of the winding moves down by 5% in turn at 1.3, 1.48, and 1.73 times the rated power respectively.

Limit Load Analysis of a Torispherical Head With Thermal Hot Spot Damage

2018 ◽  
Author(s):  
Amir Mehrizi ◽  
Soheil Nakhodchi ◽  
Reza Adibi-Asl
Keyword(s):  
Hot Spots ◽  
Hot Spot ◽  
Limit Load ◽  
Pressure Vessels ◽  
Load Carrying ◽  
Different Shapes ◽  
Service Degradation ◽  
The Common ◽  
The Impact ◽  
Inside Wall

Vessel dished heads are widely being used in storage tanks or pressure vessels. These heads are available in different shapes including hemispherical, ellipsoidal and torispherical heads. In this paper, pressure limit load of torispherical head with thermal hotspot damage is investigated. Thermal hotspots are one of the common types of in-service degradation in some pressurized components and can be considered as damage. This type of damage is usually caused by the loss of refractory lining on the inside wall of pressure components or due to a misdistribution of the flow within vessels containing catalysts. Hotspot damage potentially jeopardizes the integrity of the components [1]. In the current research, the impact of a thermal hotspot on the load carrying capacity of various shapes of torispherical heads is investigated using numerical simulation. Also, sensitivity analysis has been performed to investigate the effect of location of thermal hot spots and thickness in the torispherical heads, with and without thermal hot spot damage.

scholarly journals Improving the Creation of Hot Spot Policing Patrol Routes: Comparing Cognitive Heuristic Performance to an Automated Spatial Computation Approach

2021 ◽  
Vol 10 (8) ◽  
pp. 560
Author(s):  
Spencer P. Chainey ◽  
Jhonata A. S. Matias ◽  
Francisco Carlos F. Nunes Junior ◽  
Ticiana L. Coelho da Silva ◽  
José Antônio F. de Macêdo ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Police Officers ◽  
Hot Spots ◽  
Hot Spot ◽  
Computational Approach ◽  
Computational Techniques ◽  
Computational Approaches ◽  
Crime Hot Spots ◽  
The Creation ◽  
The Impact

Hot spot policing involves the deployment of police patrols to places where high levels of crime have previously concentrated. The creation of patrol routes in these hot spots is mainly a manual process that involves using the results from an analysis of spatial patterns of crime to identify the areas and draw the routes that police officers are required to patrol. In this article we introduce a computational approach for automating the creation of hot spot policing patrol routes. The computational techniques we introduce created patrol routes that covered areas of higher levels of crime than an equivalent manual approach for creating hot spot policing patrol routes, and were more efficient in how they covered crime hot spots. Although the evidence on hot spot policing interventions shows they are effective in decreasing crime, the findings from the current research suggest that the impact of these interventions can potentially be greater when using the computational approaches that we introduce for creating hot spot policing patrol routes.

scholarly journals Fifteen Minutes per Day Keeps the Violence Away: a Crossover Randomised Controlled Trial on the Impact of Foot Patrols on Serious Violence in Large Hot Spot Areas

2021 ◽  
Author(s):  
Matthew Bland ◽  
Michelle Leggetter ◽  
David Cestaro ◽  
Jacqueline Sebire
Keyword(s):  
Randomised Controlled Trial ◽  
Violent Crime ◽  
Hot Spots ◽  
Lower Layer ◽  
Hot Spot ◽  
Controlled Trial ◽  
Research Question ◽  
Large Area ◽  
Randomised Controlled ◽  
The Impact

Abstract Research Question Did a 15-min patrol delivery over 1 day reduce serious violent crime in large hot spots (mean size = 2 km × 2 km), without displacing such crimes to nearby areas? Data We tracked daily official crime reports in a sample of 21 high-crime Bedfordshire (UK) Lower-layer Super Output areas (LSOAs). We measured time spent by two-person police foot patrols in those areas with daily GPS data from handheld devices given to officers working on overtime. We also counted proactively initiated arrests. Methods We used a crossover randomised controlled trial on the 21 “hot spot” LSOAs, each of which was randomly assigned daily to be either in a treatment condition of 15-min of patrol (as one of seven each day) or a control condition of no patrol (as one of 14 each day) for each of 90 days. We used an intention-to-treat framework to analyse the impact of patrols on the outcome measures overall, on consecutive days of assignment to the same condition, and in 100-m ‘buffer’ zones around each hot spot. Findings We found that on treatment days the hot spots had 44% lower Cambridge crime harm index scores from serious violence than on control days, as well as 40% fewer incidents across all public crimes against personal victims. Statistically significant differences in lower prevalence, counts and harm of both non-domestic violent crime and robbery and other non-domestic crimes against personal victims were also found. We found no evidence of either displacement of serious crime into a 100-m buffer zone, nor any evidence of residual deterrence on no-patrol days following patrol days. We did find evidence of a cumulative effect: the largest differences in crime harm on control days were found in treatment days that came after 3 days of consecutive patrol in the same LSOA. Conclusions Even minimal amounts of foot patrol can prevent serious violent crime across a large area, and repeated patrols over several days help even more. Our findings suggest that, to reduce both violent and other forms of crime, uniformed officers need to patrol hot spots for short amounts of times on consecutive days.

scholarly journals Biologically consistent dose accumulation using daily patient imaging

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Nina I. Niebuhr ◽  
Mona Splinter ◽  
Tilman Bostel ◽  
Joao Seco ◽  
Clemens M. Hentschke ◽  
...  
Keyword(s):  
Hot Spots ◽  
Biological Effect ◽  
Hot Spot ◽  
Quadratic Model ◽  
High Dose ◽  
Worst Case ◽  
Dose Accumulation ◽  
Biological Dose ◽  
The Impact ◽  
Accumulated Dose

Abstract Background This work addresses a basic inconsistency in the way dose is accumulated in radiotherapy when predicting the biological effect based on the linear quadratic model (LQM). To overcome this inconsistency, we introduce and evaluate the concept of the total biological dose, bEQDd. Methods Daily computed tomography imaging of nine patients treated for prostate carcinoma with intensity-modulated radiotherapy was used to compute the delivered deformed dose on the basis of deformable image registration (DIR). We compared conventional dose accumulation (DA) with the newly introduced bEQDd, a new method of accumulating biological dose that considers each fraction dose and tissue radiobiology. We investigated the impact of the applied fractionation scheme (conventional/hypofractionated), uncertainties induced by the DIR and by the assigned α/β-value. Results bEQDd was systematically higher than the conventionally accumulated dose with difference hot spots of 3.3–4.9 Gy detected in six out of nine patients in regions of high dose gradient in the bladder and rectum. For hypofractionation, differences are up to 8.4 Gy. The difference amplitude was found to be in a similar range to worst-case uncertainties induced by DIR and was higher than that induced by α/β. Conclusion Using bEQDd for dose accumulation overcomes a potential systematic inaccuracy in biological effect prediction based on accumulated dose. Highest impact is found for serial-type late responding organs at risk in dose gradient regions and for hypofractionation. Although hot spot differences are in the order of several Gray, in dose-volume parameters there is little difference compared with using conventional or biological DA. However, when local dose information is used, e.g. dose surface maps, difference hot spots can potentially change outcomes of dose-response modelling and adaptive treatment strategies.

Spatial Hotspot Analysis of Bucharest’s Urban Heat Island (UHI) Using Modis Data

2018 ◽  
Vol 18 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Georgiana Grigoraș ◽  
Bogdan Urițescu
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Land Surface Temperature ◽  
Hot Spots ◽  
Land Surface ◽  
Hot Spot ◽  
Monitoring Network ◽  
Residential Areas ◽  
Hotspot Analysis ◽  
The City

Abstract The aim of the study is to find the relationship between the land surface temperature and air temperature and to determine the hot spots in the urban area of Bucharest, the capital of Romania. The analysis was based on images from both moderate-resolution imaging spectroradiometer (MODIS), located on both Terra and Aqua platforms, as well as on data recorded by the four automatic weather stations existing in the endowment of The National Air Quality Monitoring Network, from the summer of 2017. Correlation coefficients between land surface temperature and air temperature were higher at night (0.8-0.87) and slightly lower during the day (0.71-0.77). After the validation of satellite data with in-situ temperature measurements, the hot spots in the metropolitan area of Bucharest were identified using Getis-Ord spatial statistics analysis. It has been achieved that the “very hot” areas are grouped in the center of the city and along the main traffic streets and dense residential areas. During the day the "very hot spots” represent 33.2% of the city's surface, and during the night 31.6%. The area where the mentioned spots persist, falls into the "very hot spot" category both day and night, it represents 27.1% of the city’s surface and it is mainly represented by the city center.

Instability and Collapse in Discrete Wave Equations

2005 ◽  
Vol 5 (3) ◽  
pp. 223-241
Author(s):  
A. Carpio ◽  
G. Duro
Keyword(s):  
Continuum Limit ◽  
Wave Equations ◽  
Numerical Solutions ◽  
Blow Up ◽  
Theoretical Predictions ◽  
Initial States ◽  
The Impact ◽  
The Continuum

AbstractUnstable growth phenomena in spatially discrete wave equations are studied. We characterize sets of initial states leading to instability and collapse and obtain analytical predictions for the blow-up time. The theoretical predictions are con- trasted with the numerical solutions computed by a variety of schemes. The behavior of the systems in the continuum limit and the impact of discreteness and friction are discussed.

The family Orthotrichaceae (Bryophyta) in flora of Russia: results of revision and biogeographical review

2018 ◽  
Vol 52 (2) ◽  
pp. 519-534 ◽  
Author(s):  
V. E. Fedosov
Keyword(s):  
Hot Spots ◽  
Latitudinal Gradient ◽  
Hot Spot ◽  
Spatial Differentiation ◽  
Taxonomic Composition ◽  
Undescribed Species ◽  
Longitudinal Gradient ◽  
Biogeographic Pattern ◽  
The Family ◽  
North Pacific Region

Recent studies on Orthotrichoid mosses in Russia are summarized genus by genus. Orthotrichum furcatum Otnyukova is synonymized with Nyholmiella obtusifolia. Orthotrichum vittii is excluded from the Russian moss flora. Description of O. dagestanicum is amended. Fifty four currently recognized species from 9 genera of the Orthotrichaceae are presently known to occur in Russia; list of species with common synonyms and brief review of distribution in Russia is presented. Numerous problematic specimens with unresolved taxonomy were omitted for future. Revealed taxonomical inconsistencies in the genera Zygodon, Ulota, Lewinskya, Nyholmiella, Orthotrichum are briefly discussed. Main regularities of spatial differentiation of the family Orthotrichaceae in Russia are considered. Recently presented novelties contribute to the certain biogeographic pattern, indicating three different centers of diversity of the family, changing along longitudinal gradient. Unlike European one, continental Asian diversity of Orthotrichaceae is still poorly known, the Siberian specimens which were previously referred to European species in most cases were found to represent other, poorly known or undescribed species. North Pacific Region houses peculiar and poorly understood hot spot of diversity of Orthotrichoid mosses. Thus, these hot spots are obligatory to be sampled in course of revisions of particular groups, since they likely comprise under-recorded cryptic- or semi-cryptic species. Latitudinal gradient also contributes to the spatial differentiation of the revealed taxonomic composition of Orthotrichaceae.

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