1,227 research outputs found
Provenance evolution of ageâcalibrated strata reveals when and how South China Block collided with Gondwana
The South China Block (SCB) has been regarded by many as an integral part of Gondwana, but proposed timing and processes for its accretion to Gondwana vary and remain contentious, largely owing to the lack of reliable PanâAfrican age paleomagnetic data and tectonoâmagmatic records from the SCB. Integrated in situ UâPb ages and HfâO isotope analyses of detrital zircons from geochronologically wellâcalibrated EdiacaranâCambrian sedimentary rocks of western SCB reveal age populations of 2.51, 1.85, 1.20, 0.80, and 0.52 Ga. Detrital zircon age spectra indicate a major tectonic transition for the SCB during 0.56â0.54 Ga, interpreted to reflect the beginning of the collision between SCBâIndochina and NW India blocks. The collisional event lasted until early Ordovician, leading to the suturing of the SCBâIndochina to the northern margin of East Gondwana
Temporal Exploration in 2D Visualization of Emotions on Twitter Stream
As people freely express their opinions toward a product on Twitter streams without being bound by time, visualizing time pattern of customers emotional behavior can play a crucial role in decision-making. We analyze how emotions are fluctuated in pattern and demonstrate how we can explore it into useful visualizations with an appropriate framework. We manually customized the current framework in order to improve a state-of-the-art of crawling and visualizing Twitter data. The data, post or update on status on the Twitter website about iPhone, was collected from U.S.A, Japan, Indonesia, and Taiwan by using geographical bounding-box and visualized it into two-dimensional heat map, interactive stream graph, and context focus via brushing visualization. The results show that our proposed system can explore uniqueness of temporal pattern of customers emotional behavior
Trucks Pooling and Allocation in TSE Concept Using GIS Spatial and Novel FFOA
Strategic system logistics business entails the importance of regulating truck pooling facilities and allocating the trucks for cost optimization goals. Regulators and investors must consider spatial constraints such as the supply-demand gap and service distance. Little attention has been paid to developing decision logistics models, particularly truck pooling and allocation decisions. In this study, the FFOA and GIS were used to determine the spatial component of truck pooling decisions, providing a scenario for origin pooling and delivery distance. The model evaluates truck allocation to each city, a distance vector, a spatial factor, and city demand are used for the cost optimization goal. The results show that the FFOA model successfully defines the optimal truck allocation for each truck pooling site with a cost. The managerial implication in developing a sharing economy concept for truck logistics is to use the study's framework model result to solve challenges in truck logistics
Neutron star phase transition as the origin for the fast radio bursts and soft gamma-ray repeaters of SGR J1935+2154
Magnetars are believed as neutron stars (NSs) with strong magnetic fields.
X-ray flares and fast radio bursts (FRBs) have been observed from the magnetar
(soft gamma-ray repeater, SGR J1935+2154). We propose that the phase transition
of the NS can power the FRBs and SGRs.Based on the equation of state provided
by the MIT bag model and the mean field approximation, we solve the
Tolman-Oppenheimer-Volkoff equations to get the NS structure. With spin-down of
the NS, the hadronic shell gradually transfers to the quark shell.The
gravitational potential energy released by one time of the phase transition can
be achieved. The released energy, time interval between two successive phase
transitions, and glitch are all consistent with the observations of the FRBs
and the X-ray flares from SGR J1935+2154. We conclude that the phase transition
of an NS is a plausible mechanism to power the SGRs as well as the repeating
FRBs.Comment: 11 pages, 3 figure
Correlation of histopathologic and dynamic tissue perfusion measurement findings in transplanted kidneys
BACKGROUND: Cortical perfusion of the renal transplant can be non-invasively assessed by color Doppler ultrasonography. We performed the Dynamic Tissue Perfusion Measurement (DTPM) of the transplantâs renal cortex using color Doppler ultrasonography (PixelFlux technique), and compared the results with the histopathological findings of transplant biopsies. METHODS: Ninety-six DTPM studies of the renal transplantâs cortex followed by transplant biopsies were performed in 78 patients. The cortical perfusion data were compared with the parameter of peritubular inflammatory cell accumulation (PTC 0 to 3) based on Banff-classification system. RESULTS: A significant decrease of cortical perfusion could be demonstrated as the inflammatory cells accumulation in peritubular capillaries increased. Increasing peritubulitis caused a perfusion loss from central to distal layers of 79% in PTC 0, of 85% in PTC 1, of 94% in PTC 2, and of 94% in PTC 3. Furthermore, the perfusion loss due to peritubular inflammation was more prominent in the distal cortical layer. The extent of perfusion decline with increasing peritubulitis (from PTC 0 to PTC 3) was 64% in proximal 20% cortical layer (p20), 63% in proximal 50% cortical layer (p50), increased to 76% in distal 50% cortical layer (d50), and peaked at 90% in the distal 20% cortical layer (d20). For those without peritubulitis (PTC 0), the increase in the the Interstitial Fibrosis/Tubular Atrophy (IF/TA) score was accompanied by a significantly increased cortical perfusion. A Polyomavirus infection was associated with an increased cortical perfusion. CONCLUSIONS: Our study demonstrated that the perfusion of the renal transplant is associated with certain pathological changes within the graft. DTPM showed a significant reduction of cortical perfusion in the transplant renal cortex related to peritubular capillary inflammation
On the Effect of Lubricant on Pool Boiling Heat Transfer Performance
Ă Ă Ă For typical vapor compression processes, lubricant oil is very essential for lubricating and sealing the sliding parts and the lubricant also takes part in cushioning cylinder valves. However lubricants may migrate to the evaporator to alter the heat transfer characteristics. This is can be made clear from the viscosity and surface tension of lubricant since the viscosity of lubricant oil is about two to three orders higher than that of refrigerant whereas the corresponding surface tension of lubricant is approximately one order higher. Typically, the presence of lubricant may deteriorate heat transfer performance, yet this phenomenon becomes more severe when the lubricant mass fraction is higher. However, some previous literatures had clearly showed that the presence of lubricant oil may favor the heat transfer performance at a low lubricant fraction and the heat transfer performance may peak at a specific oil concentration. In this study, the authors aim at clarifying this phenomenon subject to pool boiling condition. Various parameters affecting the heat transfer coefficient, such as viscosity, surface tension, critical solution temperature and other thermodynamic and transport properties will be examined. Ă Ă Ă During pool boiling process, the lubricant accumulates on the surface since the refrigerant is preferential to evaporate. Hence, excess lubricant enrichment on the surface results in a thin lubricant excess layer and a thermal boundary layer, which influence the heat transfer performance, either enhancement or degradation. The excess layer may bring about a liquid-solid surface energy reduction which increases site density and reduces the bubble departure diameter, causing enhancement and degradation in heat transfer performance, respectively. However, the effect of the bubble departure diameter normally surpasses the influence of site density. This may be the crucial reason that gives rise to an occurrence of the plateau of heat transfer coefficient and followed by an apparent decline of heat transfer coefficient with a further increase of lubricant concentration. Ă Ă Ă Moreover, with the preferential evaporation of the refrigerant, a surface tension gradient is formed, which induces the Marangoni effect through which refrigerant/lubricant mixtures is supplied toward the contact line. From the phase equilibrium diagram, the maximum of the Marangoni number may occur at the low lubricant concentration with a maximum temperature difference. Hence, the presence of Marangoni effect may also be the favor the heat transfer accordingly. Also, a small fraction of lubricant will increase a larger viscosity that provide a thicker thermal boundary layer which may activate more site density, and enhances the heat transfer performance. Furthermore, miscibility may also play a crucial factor that affects the pool boiling heat transfer performance. The fluid with a smaller difference between the bulk fluid temperature and critical solution temperature may yield a better heat transfer performance by drawing superheated liquid onto the bubble sides.
Characterization of flow-pattern and heat transfer of micro flat heat pipes
Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.In this study, thermal performance and flow visualization of
a double layer flat micro vapor chamber are carried out. Two
micro vapor chambers having pin fin and pin fin array support
structure were fabricated and tested. The micro vapor chambers
were composed of silicon and glass wafers having an overall
size of 35 mm Ă 40 mm Ă 1.525 mm. Test results show that
both the pin fin and pin fin array vapor chambers show
appreciably lower thermal resistance as compared to the solid
silicon counterpart, the thermal resistance of the pin fin vapor
chamber is about 52-60% of the solid silicon whereas the
corresponding thermal resistance of pin fin array is only 17-20
% of the solid silicon. The thermal resistance of the pin fin
vapor chamber is moderately increased with the increase of
supplied power whereas opposite trend is encountered for the
pin fin array. The phenomenon is associated with the influence
of dry-out phenomenon. It is found that the pin fin array vapor
chamber is still in function even for an upside-down
arrangement. The thermal resistance, however, is reduced with
the rise of tilt angle, and the vertical arrangement gives the
lowest thermal resistance. However, the thermal resistance is
considerably increased if the heat source is placed upwards, and
the corresponding thermal resistance for an upside-down heat
source can be threefold higher than that of the vertical
arrangement.dc201
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