Variation in Thermal time model Parameters Between Two Contrasting Chickpea (<i>Cicer arietinum</i>) cultivars

A laboratory experiment was carried out to determine the effect of different constant temperatures on germination and early seedling establishment and to study the variation among parameters of thermal time model parameters for two contrasting chickpea cultivars . Seeds were subjected to six constant temperatures from 10 o C to 35 o C . A complete randomized design was used with four replication. Analysis of variance showed significant differences among treatments for all characters studied. The final germination percentage significantly increased with increasing temperature up to 25 ° C, and thereafter there was a sharp decrease in final germination at 30 ° and 35 ° C. Desi type cultivar (small seeded) “Jabel Marra” significantly exhibited higher final germination percentage and lower germination rate compared with the kabui type cultivar “Shendi” at all temperatures. The median (θ T(50) ) of the thermal time was significantly differ between the two chickpea cultivars. The large seeded cultivars (shendi) recorded significantly higher median thermal time than the small seeded cultivars (Jabel Marra). The results also revealed a significant differences between the two cultivars in all thermal time model parameters. The small seeded cultivar (Jabel Marra) scored lower total dry matter and temperature tolerance index (TTI) compared to the large seeded cultivar (Shendi) at all temperatures studied.

Impact of thermal time shift on wheat phenology and yield under warming climate in the Huang-Huai-Hai Plain, China

Given climate change can potentially influence crop phenology and subsequent yield, an investigation of relevant adaptation measures could increase the understanding and mitigation of these responses in the future. In this study, field observations at 10 stations in the Huang- Huai-Hai Plain of China （HHHP） are used in combination with the Agricultural Production Systems Simulator （APSIM）-Wheat model to determine the effect of thermal time shift on the phenology and potential yield of wheat from 1981-2009. Warming climate speeds up winter wheat development and thereby decreases the duration of the wheat growth period. However, APSIM-Wheat model simulation suggests prolongation of the period from flowering to maturity （Gr） of winter wheat by 0.2-0.8 d·10yr^-1 as the number of days by which maturity advances, which is less than that by which flowering advances. Based on computed thermal time of the two critical growth phases of wheat, total thermal time from floral initiation to flowering （TT_floral_initiation） increasesd in seven out of the 10 investigated stations. Altematively, total thermal time from the start of grainfilling to maturity （TT_start grain_fill） increased in all investigated stations, except Laiyang. It is thus concluded that thermal time shift during the past three decades （1981- 2009） prolongs Gr by 0.2-3.0 d·10yr^-1 in the study area. This suggests that an increase in thermal time （TT） of the wheat growth period is critical for mitigating the effect of growth period reduction due to warming climatic condition. Furthermore, climate change reduces potential yield of winter wheat in 80% of the stations by 2.3-58.8 kg·yr^-1. However, thermal time shift （TTS） increases potential yield of winter wheat in most of the stations by 3.0-51.0 Received September 16, 2015; accepted January 24, 2016 kg·yr^-1. It is concluded that wheat cultivars with longer growth periods and higher thermal requirements could mitigate the negative effects of warming climate on crop production in the study area.

Thermal time constant of a terminating type MEMS microwave power sensor

A terminating type MEMS microwave power sensor based on the Seebeck effect and compatible with the GaAs MMIC process is presented.An electrothermal model is introduced to simulate the thermal time constant. An analytical result,about 160 ms,of the thermal time constant from the non-stationary Fourier heat equations for the structure of the sensor is also given.The sensor measures the microwave power jumping from 15 to 20 dBm at a constant frequency 15 GHz,and the experimental thermal time constant result is 180 ms.The frequency is also changed from 20 to 10 GHz with a constant power 20 dBm,and the result is also 180 ms.Compared with the analytical and experimental results,the model is verified.

A Numerical Algorithm Based on Quadratic Finite Element for Two-Dimensional Nonlinear Time Fractional Thermal Diffusion Model

In this article,a high-order scheme,which is formulated by combining the quadratic finite element method in space with a second-order time discrete scheme,is developed for looking for the numerical solution of a two-dimensional nonlinear time fractional thermal diffusion model.The time Caputo fractional derivative is approximated by using the L2-1formula,the first-order derivative and nonlinear term are discretized by some second-order approximation formulas,and the quadratic finite element is used to approximate the spatial direction.The error accuracy O(h3+
t2)is obtained,which is verified by the numerical results.

Numerical Simulation of Vacuum Heat Treatment Thermal Hysteresis Time of GH4169 Superalloy Workpiece

A nonlinear finite element model of vacuum heat treatment process was developed. In this model, influence of many factors, such as nonlinear heat radiation, temperature-dependent thermal physical properties of material are considered. The temperature field of GH4169 alloy workpiece during vacuum heat treatment process was calculated using finite element software MSC.Marc, and the thermal hysteresis time of the workpiece was predicted. An experiment of vacuum heat treatment of GH4169 superalloy workpiece was carried out to verify the calculation. The experimental results of temperature profile agree well with the simulated results. This work lays a theoretical foundation for optimizing technical parameter of vacuum heat treatment process.

Stochastic transient analysis of thermal stresses in solids by explicit time-domain method

Stochastic heat conduction and thermal stress analysis of structures has received considerable attention in recent years.The propagation of uncertain thermal environments will lead to stochastic variations in temperature fields and thermal stresses.Therefore,it is reasonable to consider the variability of thermal environments while conducting thermal analysis.However,for ambient thermal excitations,only stationary random processes have been investigated thus far.In this study,the highly efficient explicit time-domain method(ETDM)is proposed for the analysis of non-stationary stochastic transient heat conduction and thermal stress problems.The explicit time-domain expressions of thermal responses are first constructed for a thermoelastic body.Then the statistical moments of thermal displacements and stresses can be directly obtained based on the explicit expressions of thermal responses.A numerical example involving non-stationary stochastic internal heat generation rate is investigated.The accuracy and efficiency of the proposed method are validated by comparison with the Monte-Carlo simulation.

Estimation of the kinetic parameters for thermal decomposition of HNIW and its adiabatic time-to-explosion by Kooij formula

A differential/integral method to estimate the kinetic parameters(apparent activation energy Eaand pre-exponential factor A) for thermal decomposition reaction of energetic materials based on Kooij formula are applied to study the nonisothermal decomposition reaction kinetics of hexanitrohexaazaisowurtzitane(HNIW) by analyzing nonisothermal DSC curve data. The apparent activation energy(Ea) obtained by the integral isoconversional non-isothermal method based on Kooij formula is used to check the constancy and validity of apparent activation energy by the differential/integral method based on Kooij formula. The most probable mechanism function of thermal decomposition reaction of HNIW is determined by a logical choice method. The equations for calculating the critical temperatures of thermal explosion(Tb) and adiabatic time-toexplosion(tTIad) based on Kooij formula are used to calculate the values of Tband tTIadto evaluate the thermal safety and heat-resistant ability of HNIW. All the original data needed for analyzing the kinetic parameters are from nonisothermal DSC curves. The results show that the kinetic model function in differential form and the values of Eaand A of decomposition reaction of HNIW are 3(1 a)[ ln(1 a)]2/3, 152.73 kJ mol 1and 1011.97s 1, respectively, and the values of self-accelerating decomposition temperature(TSADT), Tband tTIadare 486.55 K, 493.11 K and52.01 s, respectively.

Evaluation of NBI absorption and fast ion stored energy to improve thermal energy confinement time calculation in EAST

The absorption of neutral beam power and the fast ion stored energy in EAST plasmas with neutral beam injection(NBI)is analyzed to improve the calculation of thermal energy confinement time.The neutral beam power absorption and fast ion stored energy are systematically calculated using the TRANSP code,through the investigation of global parameters including plasma current,line averaged density and beam energy.Results have shown that scaling laws for the NBI absorption coefficient and fast ion energy rate are obtained through statistical analysis.A comparison of the confinement improvement factor H98y2 with these new scaling laws against those assuming fixed coefficients is given.

Thermal Behavior, Specific Heat Capacity and Adiabatic Time-to-explosion of GDN

A new compound, [（NH2）2C=NH2]＋N（NO2）2-（GDN）, was prepared by mixing ammonium dinitramide （ADN） and guanidine hydrochloride in water. The thermal behavior of GDN was studied under the non-isothermal conditions with DSC and TG/DTG methods. The apparent activation energy（E） and pre-exponential constant（A） of the exothermic decomposition stage of GDN were 118.75 kJ/mol and 10^10.86 s^-1, respectively. The critical temperature of the thermal explosion（Tb） of GDN was 164.09 ℃. The specific heat capacity of GDN was determined with the Micro-DSC method and the theoretical calculation method, and the standard molar specific heat capacity was 234.76 J·mol^-1·K^-1 at 298.15 K. The adiabatic time-to-explosion of GDN was also calculated to be a certain value between 404.80 and 454.95 s.

Temperature Dependent Zeno Time for a Two Level Atom Traversing through a Thermal Magnetic Barrier in the Framework of Weak Measurement

The Zeno time has been calculated for a metastable two-level atom tunneling through a interacting thermal magnetic field. The process of weak measurement has been utilized for the estimation of the timescale. Zeno time has been shown to be temperature dependent. From the calculation it is evident that the Zeno time decreases with the increase of temperature. Moreover, the result restricts the Zeno time to a maximum limiting value, irrespective of how frequent the measurement process is.

真空热固结联合强夯处理工程废浆试验研究

为解决真空热固结过程中热量与真空负压在土体中衰减而导致土体加固效果不均匀的问题,利用强夯法能改善土体密实度的特性,将真空热固结法与强夯法联合应用于工程废浆的加固处理,通过4组室内模型试验研究不同夯击时机对土体加固效果的影响。结果表明:沉降速率为每3 d沉降4 cm时为最佳夯击时机,土体表面沉降比其他试验组提高26.55%、11.72%和3.74%,对工程废泥浆的处理效果最佳,能有效解决真空热固结下深层土体加固效果差的问题,并提高土体的均匀性。通过微观结构分析发现,合适的夯击时机下,由于土颗粒之间的孔隙重分布,导致土体密实程度更高,十字板剪切强度随之增大。此外,内部孔隙重分布产生微裂缝形成的排水通道对排水有一定的促进作用,进一步提升了固结效果,在合适的夯击时机下,对土体的十字板剪切强度与固结度均有促进作用。

Cross-Correlation between Global Temperature and Atmospheric CO2 with a Temperature-Leading Time Lag

The temperature change and rate of CO2 change are correlated with a time lag, as reported in a previous paper. The correlation was investigated by calculating a correlation coefficient r of these changes for selected ENSO events in this study. Annual periodical increases and decreases in the CO2 concentration were considered, with a regular pattern of minimum values in August and maximum values in May each year. An increased deviation in CO2 and temperature was found in response to the occurrence of El Niño, but the increase in CO2 lagged behind the change in temperature by 5 months. This pattern was not observed for La Niña events. An increase in global CO2 emissions and a subsequent increase in global temperature proposed by IPCC were not observed, but an increase in global temperature, an increase in soil respiration, and a subsequent increase in global CO2 emissions were noticed. This natural process can be clearly detected during periods of increasing temperature specifically during El Niño events. The results cast strong doubts that anthropogenic CO2 is the cause of global warming.

Thermal and photoperiodic requirements of the seedling stage of three tropical forest species

Air temperature and photoperiod play an important role in the seedling development for tropical forest species.Both variables are sensitive to climate,and so evaluating thermal and photoperiodic effects on seedling development is fundamental,especially for climate change studies.Methods to quantify thermal time and the energy required for plants to reach a development stage include air temperature and cardinal temperatures.The photoperiod will also affect physiological reactions of a plant and thus its development.Here we evaluated the six thermal time methods widely used to compute thermal requirement,and identified the influence of the photoperiod from the 2015 and2016 growing seasons and 12 sowing dates in Itajubá,Minas Gerais state,Brazil,on seedling development of three native tropical forest species Psidium guajava L.(Myrtaceae),Citharexylum myrianthum Cham.(Verbenaceae),and Bixa orellana L.(Bixaceae).The method used to quantify thermal time influenced the analytical results of seedling development;the one that considered three cardinal temperatures and compared them with the mean air temperature(Method5)performed better in computing thermal requirements.The influence of photoperiod on seedling development was inconclusive for the three species,but all three developed better in mild temperatures(between 13.3℃and 26.9℃)with a photoperiod shorter than 13 h.

Dynamic thermal modeling and parameter identification for a monolithic laser diode module

We improved the thermal equivalent-circuit model of the laser diode module（LDM） to evaluate its thermal dynamic properties and calculate the junction temperature of the laser diode with a high accuracy.The thermal parameters and the transient junction temperature of the LDM are modeled and obtained according to the temperature of the thermistor integrated in the module.Our improved thermal model is verified indirectly by monitoring the emission wavelength of the laser diode against gas absorption lines,and several thermal parameters are obtained with the temperature uncertainty of 0.01 K in the thermal dynamic process.

Thermal Energy of Confined Gravitons can Vary Cold Geodesic Curves

Internal energy of real warm bodies can change their kinetic-potential energy balance on Keplerian orbits and relativistic geodesic. Chiral nature of the mass results in chirality of gravitons and their energy confinement within the constant energy charge of a moving thermodynamical body. Zero energy-momentum gravitons provide dissipative self-heating and spiral fall of massive stars on gravitating centers. Computed self-heating of the pulsar PSR B1913＋16 quantitatively describes its period decay without an outward emission of metric waves in question. Deviation of warm bodies from geodesic trajectories of cold point matter complies with Einstein＇s directives toward pure field physics of material space plenum without metric singularities.

消防服衣下空气层结构对人体热防护的影响规律

为降低火灾环境对消防员皮肤烧伤的危害,构建空气层三维传热模拟装置,模拟服装开口处的衣下空气层状态,并开展低热辐射条件下的热暴露试验,探究着装人体与外界环境的热量交换及对人体皮肤热防护的影响规律。结果表明:与封闭空气层相比,开放空气层条件下织物受热面的峰值温度更低;空气层厚度的增加和边界的开放能够提升织物系统的热防护能力;3 mm空气层条件下,封闭状态的热防护性能更好,而其它厚度下开放空气层的防护能力更好;与无空气层条件相比,3~18 mm的封闭空气层可将热流密度衰减提升16.2%~44.5%、皮肤温度降低9%~26.7%、二级烧伤时间延长10.0%~100.8%;开放空气层可将热流密度衰减提升8.0%~50.7%、皮肤温度降低4.7%~30.0%、二级烧伤时间延长7.2%~140.9%。

考虑火电时滞特性的电池储能集群调频综合控制策略研究

该文提出一种电池储能集群参与电网调频的综合控制策略,能实现较好的频率控制效果和电池储能集群的安全经济运行。首先,针对火电机组响应时滞特性导致的调频精度低,甚至在负荷快速变化下反向错误调节的问题,提出基于全通滤波的电池储能-火电机组联合调频控制模型,并结合实际负荷扰动数据的频谱分析进一步提出模型参数设计方法,使电池储能作为相移器控制负荷扰动相位与火电机组出力基本一致,有效地改善了调频效果。然后,提出基于调频周期内功率权重动态修正与储能单元依次投入的荷电状态(SOC)一致性控制策略,解决了SOC差异较小时一致性迭代方向与调频功率响应方向相反的问题,兼顾SOC一致性维持和功率响应,并减小了储能单元频繁投切对其使用寿命的影响;同时考虑调频过程电池储能需频繁充放电状态切换,采用储能集群分组控制模式以减小储能集群寿命损耗,提高储能调频经济性。最后,搭建某区域电网仿真模型验证该文控制策略的有效性。

低温长时间热处理过程中氧化和加热对海参体壁胶原纤维结构的影响

以新鲜海参为研究对象,考查低温(60℃)长时间热处理过程中氧化和加热对其质构特性的影响,并进一步从新鲜海参体壁中提取完整的胶原纤维,分别进行氧化处理、热处理及氧化协同热处理后,采用差示扫描量热(DSC)仪、冷冻扫描电子显微镜(cryo-SEM)、傅里叶变换红外光谱(FTIR)仪、电子自旋共振波谱(ESR)仪等对其热稳定性、微观结构、蛋白质二级结构、氧化程度等变化情况进行研究。结果表明:单一氧化处理对胶原纤维仅有氧化降解作用。单一热处理会使胶原纤维发生氧化、变性、降解等变化。相较于两种单一处理方式,经氧化协同热处理后,胶原纤维结构被破坏得更加明显,处理1 h后,胶原纤维内的蛋白聚糖桥连结构发生明显断裂,处理24 h后,在15~24℃附近出现新的吸热峰,胶原纤维发生明胶化;随着处理时间的延长,胶原纤维结构的孔径进一步收缩,且发生破损;氧化协同热处理能促进热处理对胶原纤维的氧化程度,并使大分子蛋白质发生降解,增加羟脯氨酸、糖胺聚糖(GAG)等可溶性小分子物质溶出。因此,氧化协同热处理能使胶原纤维发生氧化、变性、聚集、降解等变化,进而影响海参体壁的质构特性。

高温合金涡轮叶片热疲劳损伤行为实时监测与评估系统设计

本文设计了一种高温合金涡轮叶片热疲劳损伤行为实时监测与评估系统,旨在应对航空发动机叶片在高温环境下的复杂服役条件。系统通过传感采集、数据处理和评估决策模块协同工作,实现对叶片损伤的实时监测、数据分析和健康状态评估。实验验证表明,该系统能够准确捕捉叶片热疲劳损伤的演化特征,为保障发动机安全运行及优化维护策略提供了有效的技术支持。

三时段多模式保温护理在经尿道前列腺电切手术中的护理效果分析

目的:分析探讨三时段多模式保温护理在经尿道前列腺电切手术中的护理效果。方法:选取徐州医科大学附属第三医院于2018年1月~2024年4月接受经尿道前列腺电切手术的患者86例作为研究对象,使用随机数字表法分为常规护理组(n=43)和多模式护理组(n=43)。常规护理组实施常规护理,多模式护理组实施三时段多模式保温护理。比较两组患者不同时间体温变化情况、护理前后前列腺症状、消化功能情况以及并发症发生情况等护理效果。结果:常规护理组和多模式护理组不同时间体温变化组间、时间、交互比较,差异有统计学意义(P<0.05);常规护理组手术进行30 min、术后2 h体温均低于术前,且术后2 h体温低于手术进行30 min,多模式护理组手术进行30 min体温低于术前,术后2 h体温高于手术进行30 min且高于术前,差异有统计学意义(P<0.05);多模式护理组术前、手术进行30 min、术后2 h体温均高于常规护理组,差异有统计学意义(P<0.05)。护理前,两组IPSS评分比较,差异无统计学意义(P>0.05);护理后,两组IPSS评分均低于护理前,差异有统计学意义(P<0.05),且多模式护理组IPSS评分低于常规护理组,差异有统计学意义(P<0.05)。肛门排气时间相比较,多模式护理组少于常规护理组,差异有统计学意义(P<0.05);肛门排便时间相比较,多模式护理组少于常规护理组,差异有统计学意义(P<0.05)。常规护理组并发症共发生11例(25.58%),多模式护理组并发症共发生3例(6.98%);多模式护理组并发症总发生率低于常规护理组,差异有统计学意义(P<0.05)。结论:三时段多模式保温护理在经尿道前列腺电切手术中护理效果良好。