Model study of relationship between local temperature and artificial heat release

In recent decades,it presents a more obvious temperature rise in urban area along with the global warming.City is generally the center of human society,so the study on urban temperature variation will be helpful to our city development planning that is to reduce urban warming.The study is also helpful to a more comprehensive understanding of the causes of climate warming,which could provide a theoretical support to the government to make more reasonable international energy policies.Local temperature rise has different mechanisms with the global warming:large quantities of artificial heat release from the energy consumption will stay in urban areas for a period of time,which will inevitably influence the short-term trend of the local temperature change.Based on that view,a structural thermodynamic model was established in this paper to investigate the effect of the artificial heat release on the urban local temperatures.In the model,the city environment was divided into Human,Local,Outer three blocks,and then the heat and temperatures of the blocks were analyzed based on the laws of thermodynamics.After that,the effect of artificial heat release in Human block on the local temperatures was clarified.The model shows that the artificial heat release has an approximately linearly promoting effect on the local temperature rise,and the more the heat release is,the stronger the effect is.In addition,a validation of that model was carried out based on some national statistical data.The data of temperatures and artificial heat release of some provincial capitals of China were analyzed with linear regression extrapolation method and Pearson correlation statistical method.The results show that in most capital cities,the temperature variations basically depend on the artificial heat release in a linear relationship,which usually becomes more apparent with the increase of the artificial heat release in both spatial and temporal dimensions.The conclusions of the statistics have good conformity with the model and the rationality of the model is verified.

Gold nanorods conjugated upconversion nanoparticles nanocomposites for simultaneous bioimaging,local temperature sensing and photothermal therapy of OML-1 oral cancer cells

The major challenge in photothermal therapy(PTT)is to develop nanocomposites that simultaneously exhibit bioimaging and PTT under a single near-infrared(NIR)irradiation with high therapeutic efficiency.Herein,we present a multifunctional nanocomposite synthesized by linking NaYF_(4):Yb^(3+),Er^(3+)upconversion nanoparticles(UCNPs)with gold nanorods(AuNR)to exhibit fluorescence label-ing,local temperature sensing and photothermal functions simul-taneously with a single NIR laser excitation.The AuNR-NaYF_(4):Yb^(3+),Er^(3+)nanocomposite particles displayed better photothermal prop-erties compared with pure AuNRs or a blend of AuNRs and NaYF_(4):Yb^(3+),Er^(3+)UCNPs.The temperature-dependent upconversion lumi-nescence(UCL)property was used to determine local temperature at the nanocomposite particles,which is useful for selecting appro-priate irradiation dosage for PTT.The therapeutic performance of the nanocomposites in PTT for OML-1 oral cancer cells was deter-mined.For cell labeling,we successfully labeled streptavidin-linked nanocomposite particles on the surface of OML-1 oral cancer using anti-human epidermal growth factor receptor 2(anti-Her2)anti-body.Finally,the nanocomposite particles caused exceptional destruction of cancer cells up to 70%dead cells under 976 nm laser irradiation for only one min at 0.3 W/cm^(2)which is below the maximal permissible exposure of human skin.

Local temperature and El Niño Southern Oscillation influence migration phenology of East Asian migratory waterbirds wintering in Poyang,China

Temperature is a critical factor influencing avian phenology,due to its direct impact on food and water availability.Most previous studies have focused on the timing of spring migration and the arrival of birds at breeding grounds along the European and American flyways;little is known about migration ecology at the wintering sites along the Asian flyways.Using linear regression models,this study investigates how local temperature variation and EI Niño Southern Oscillation(ENSO)influences the arrival and departure timing of 9 waterbird species breeding in Mongolia or Siberia and overwintering in Poyang,China from 2002 to 2013.Birds mainly arrive at Poyang in October and depart for their breeding sites in March.Out of the 9 species,6 show a strong negative relationship between departure time and overwintering temperature in Poyang.Departure dates also show a negative association with overwintering ENSO and March ENSO for two species.Both local and large-scale climate indices show no influence on the arrival timing of waterbirds.We suggest that birds react to the annual variation of overwintering temperature:an earlier departure of waterbirds is facilitated by a warmer overwintering period and vice versa.The long-term accumulated temperature effect is more pronounced than ENSO and the short-term local temperature effect.Our findings could help quantify the potential impact of global warming on waterbirds.

Analysis of coseismic effect on temperature in the Three Gorges well network

Through the Three Gorges well network, we examine different coseismic changes in water temperature caused by local earthquakes since 2008, and offer a mechanistic explanation.The relations between the coseismic changes in water temperature and the parameters of distant and local earthquakes are deduced.

CONSTITUTIVE EQUATION WITH ORDERED PARAMETERS FOR VISCOELASTIC MATERIAL CONTAINING DEFECTS

Based on the experimental results of local temperature field formed in the evolution period of defects, the defect field is defined by this internal temperature field. The evolutionary processes of statistically correlative meso-scopic defects are analysed with the growth rate and nucleation rate of the meso-defect, and it is deemed that the dynamic failure process of the viscoelastic material with defects can be quantitatively described by the normal method of the procedure of heat wave transmission. The defect field is regarded as a complex system of the union of the real sets and null sets, its main characteristics depending on the stratum hypothesis about the activities of the subsystems of the highest stratum described by ordered parameters. The fluctuation of ordered parameters is demonstrated by means of the projection operator method. The constitutive equation with ordered parameters for the meso-defect evolutionary state of viscoelastic material with defects is deduced from the nonlinear rheological dynamic approach, and its solution is obtained.

Micro thermoelectric devices:From principles to innovative applications

Thermoelectric devices(TEDs),including thermoelectric generators(TEGs) and thermoelectric coolers(TECs) based on the Seebeck and Peltier effects,respectively,are capable of converting heat directly into electricity and vice versa.Tough suffering from low energy conversion efficiency and relatively high capital cost,TEDs have found niche applications,such as the remote power source for spacecraft,solid-state refrigerators,waste heat recycling,and so on.In particular,onchip integrable micro thermoelectric devices(μ-TEDs),which can realize local thermal management,on-site temperature sensing,and energy harvesting under minor temperature gradient,could play an important role in biological sensing and cell cultivation,self-powered Internet of Things(IoT),and wearable electronics.In this review,starting from the basic principles of thermoelectric devices,we summarize the most critical parameters for μ-TEDs,design guidelines,and most recent advances in the fabrication process.In addition,some innovative applications of μ-TEDs,such as in combination with microfluidics and photonics,are demonstrated in detail.

Effect of heat-producing needling technique on the local skin temperature:A clinical study

Objective:This clinical study was performed to examine the influence of heat-producing acupuncture(HPA)treatment on the local skin temperature of Zusanli(足三里ST36)acupoint in healthy participants.Methods:30 healthy participants received four successive sessions of heat-producing acupuncture(HPA),non-acupoint HPA(NAHPA),normal stable acupuncture(Norm)and non-invasive sham acupuncture(Sham)on the ST36 acupoint in random order.Within each treatment session,the local skin temperature of ST36 acupoint and basal body temperature of each participant were measured at 1 min before needle insertion(T1 B),just after needle insertion and manipulation(T0),5 min after needle insertion(T5)and 5 min after needle removal(T5 A).Visual Analogue Scale(VAS)scores of the participants’perceived needling and heat sensation felt during the acupuncture treatment period(T0-T5)were also recorded on a scale of 1 to 10.Results:Intra-session group statistical analyses of the different time points in the HPA treatment session group demonstrates that ST36 local skin temperature remained relatively stable between T1 B and T0,increased significantly between T0 and T5 and decreased significantly between T5 and T5 A.For intersession group statistical analysis of all treatment session groups,the increase in local skin temperature of ST36 acupoint between T0 and T5 in the HPA treatment session group was significantly higher than those of the NAHPA treatment session group(P<0.01),Norm treatment session group(P<0.01)and Sham treatment session group(P<0.01).The decrease in local skin temperature of ST36 acupoint between T5 and T5 A in the HPA treatment session group was also significantly more than those of NAHPA treatment session group(P<0.05),Norm treatment session group(P<0.01)and Sham treatment session group(P<0.001).Conclusion:Our study provides evidence that HPA treatment performed significantly better than the other three treatments in elevating the local skin temperature of ST36 acupoint temporarily.Our results also align with those of many previous clinical studies on HPA and related acupuncture manipulations.

Experimental Investigation on Local Behaviors of PEMFC with Segmented Cell

When designing a cell stack and developing an operational strategy for proton exchange membrane fuel cell,it is critical to characterize the local current,water and heat.To measure distributions of current density,relative humidity and temperature for both anode and cathode simultaneously along the straight parallel flow channels,this paper uses a segmented tool based on the multilayered printed circuit board flow field plates with embedded sensors.In this study,two kinds of experimental operations of fuel cell reactants are carried out for comparison:the co-flow operation with identical gas flow direction of hydrogen and air and the counter-flow operation with opposite gas flow directions.The detected relative humidity(RH)distributions of both anode and cathode indicate that the asymmetry of RH distribution at two sides of the membrane in counter-flow operation is better at holding water inside the fuel cell compared with the co-flow operation.The in situ measured performance distributions show that segments around the middle of the fuel cell contribute the highest current in counter-flow operation,while for co-flow operation,the current peak locates near the outlet of reactants.

Green and large-scale production of ammonia:Laser-driven pyrolysis of nitrogen-enriched biomass

As a vital chemical,ammonia(NH3)plays an irreplaceable role in many fields such as chemical synthesis and energy storage.Green renewable biomass can be converted into biofuels,but its nitrogen resources are underused throughout.Laser-driven pyrolysis is envisaged to debuts as a bridge to connect them to realize the direct conversion from nitrogen-rich biomass into ammonia.The pulsed laser-induced local-transient thermal effect recognized the biological nitrogen resources conversion,such as cheap and plentiful yeasts,to small gaseous molecules and achieved spectacular ammonia production rate up to 260.4 mg/h,an order of magnitude higher performance than thermochemical ammonia synthesis.Simultaneously,the tiny hot point generated by a low-energy laser(20W)guarantees the whole ammonia synthesis reaction systemis in amild environment of low temperature and normal pressure.Additionally,the remaining solid residue after laser-driven pyrolysis also can be further exploited as a highly active catalyst for electrocatalytic nitrate reduction reaction(NIRR).