Effect Of Ambient Temperature Research Articles

The effect of ambient temperature on bird embryonic development: a comparison between uniparental incubating silver‐throated tits and biparental incubating black‐throated tits

The temperature experienced by avian embryos during development has important impacts on their growth and post‐hatching phenotypes. Ambient temperature can directly affect avian nest temperature and indirectly affect it through its impact on parental incubation behaviours. Because the nests of uniparental incubators are usually left unattended more frequently than the nests of biparental incubators whose nests can be attended by another bird when one bird leaves the nest, we predict that the effect of ambient temperature on nest temperature and thus on embryonic development (specifically, incubation period length and hatching success) and post‐hatching phenotype (i.e. potential carry‐over effect on nestling body mass and condition) should be greater in uniparental incubators than in biparental incubators. To test this prediction, we studied two congeneric species, the biparental incubating black‐throated tits Aegithalos concinnus and the uniparental incubating silver‐throated tits A. glaucogularis. We found that although the embryos of the two species both developed faster (shorter incubation period length) when ambient temperature was higher, the slope was significantly greater for silver‐throated tits than for black‐throated tits, consistent with our prediction of a greater effect of ambient temperature on embryonic development in silver‐throated tits. However, the result was not due to a greater effect of ambient temperature on nest temperature, because nest temperatures of the two species had positive relationships with ambient temperature in a similar way. Therefore, it implies a greater response of silver‐throated tit embryos to temperature change. In addition, ambient temperature during the incubation stage did not affect either hatching success or nestling body mass and condition in both species. Although our predictions were not fully supported, our findings highlight the different responses of embryonic development to environmental changes between a uniparental incubator and a biparental incubator, and suggest further research to explore the mechanisms.

Too hot to thrive: a qualitative inquiry of community perspectives on the effect of high ambient temperature on postpartum women and neonates in Kilifi, Kenya

ObjectiveTo understand community perspectives on the effects of high ambient temperature on the health and wellbeing of neonates, and impacts on post-partum women and infant care in Kilifi.DesignQualitative study using key informant interviews, in-depth interviews and focus group discussions with pregnant and postpartum women (n = 22), mothers-in-law (n = 19), male spouses (n = 20), community health volunteers (CHVs) (n = 22) and stakeholders from health and government ministries (n = 16).SettingsWe conducted our research in Kilifi County in Kenya’s Coast Province. The area is largely rural and during summer, air temperatures can reach 37˚C and rarely go below 23˚C.Data analysisData were analyzed in NVivo 12, using both inductive and deductive approaches.ResultsHigh ambient temperature is perceived by community members to have direct and indirect health pathways in pregnancy and postpartum periods, including on the neonates. The direct impacts include injuries on the neonate’s skin and in the mouth, leading to discomfort and affecting breastfeeding and sleeping. Participants described babies as “having no peace”. Heat effects were perceived to be amplified by indoor air pollution and heat from indoor cooking fires. Community members believed that exclusive breastfeeding was not practical in conditions of extreme heat because it lowered breast milk production, which was, in turn, linked to a low scarcity of food and time spend by mothers away from their neonates performing household chores. Kangaroo Mother Care (KMC) was also negatively affected. Participants reported that postpartum women took longer to heal in the heat, were exhausted most of the time and tended not to attend postnatal care.ConclusionsHigh ambient temperatures affect postpartum women and their neonates through direct and indirect pathways. Discomfort makes it difficult for the mother to care for the baby. Multi-sectoral policies and programs are required to mitigate the negative impacts of high ambient temperatures on maternal and neonatal health in rural Kilifi and similar settings.

Experimental investigations on a coupled metal hydride based thermal energy storage system

Thermal energy storage using coupled metal hydride reactors is attractive because it offers several advantages such as one-time hydrogen loading, high thermal storage density, compactness and possibility of simultaneous heating and cooling. This study presents experimental investigations on a coupled metal hydride based thermal energy storage system. Based on compatibility criteria of hydrides described in this work, LaNi4.25Al0.75 for thermal energy storage and La0.75Ce0.25Ni5 for hydrogen storage were chosen. The study employed two novel cartridge type coupled reactors with enhanced heat transfer surfaces. The effects of heat source and ambient temperatures on the system performance were investigated. The study reveals that coupled hydride systems with suitable pairs of hydrides can deliver high energy storage capacities at good thermal efficiencies. The heat output of 227.7 kJ was achieved with a heat transfer rate of 130.7 W at 55.7 % efficiency. The hydrogen storage alloy exhibited good compatibility with the energy storage alloy with fast hydrogenation and dehydrogenation. It also produced a cooling effect of 171.8 kJ while desorbing hydrogen.

Effects of Ambient Temperature and Magnitude of the Vibration on the Dynamics of Pre-Stressed Precast Isolated Pedestrian Bridges

The dynamic properties of structures are known as inherent properties dependent on the mass and stiffness parameters. However, recent studies showed that the temperature and the magnitude of the vibration affect them. This study aims to reveal how the ambient temperature and human-induced vibrations alter the modal characteristics of pre-stressed precast isolated pedestrian bridges. For this aim, operational modal analyses have been applied to the Istanbul Medeniyet University pedestrian bridge. Three-bay pre-stressed precast and isolated bridge has been connecting the two campuses of the university for six years and its dynamic properties were investigated during its construction. In this study, the dominant frequencies of the bridge have been determined to see if they changed or not for its service life. Secondly, the dynamic response of the longest bay of the bridge has been evaluated under different temperatures and human-induced vibrations. Through a year, twelve acceleration measurements have been gathered in a temperature range of 5 – 33 °C and representing the different levels of human-induced vibrations, some jumping actions were applied and its response was recorded. While the performed analyses proved that, the dominant frequencies are dependent on the ambient temperature, no significant correlation was obtained between the amplitude of the vibration and the dominant frequencies of the bridge. High-amplitude vibrations have been used for the vibration serviceability check of the bridge, and it is seen that it satisfies the requirements set by different codes.

Effect of Ambient Temperature and Solar Irradiance on Photovoltaic Modules' Performance

Effect of Ambient Temperature and Solar Irradiance on Photovoltaic Modules' Performance

Cold Ambient Temperature Does Not Alter Subcutaneous Abdominal Adipose Tissue Lipolysis and Blood Flow in Endurance-Trained Cyclists

This study sought to investigate the effect of cold ambient temperature on subcutaneous abdominal adipose tissue (SCAAT) lipolysis and blood flow during steady-state endurance exercise in endurance-trained cyclists. Ten males (age: 23 ± 3 years; peak oxygen consumption: 60.60 ± 4.84 ml·kg−1·min−1; body fat: 18.4% ± 3.5%) participated in baseline lactate threshold (LT) and peak oxygen consumption testing, two familiarization trials, and two experimental trials. Experimental trials consisted of cycling in COLD (3 °C; 42% relative humidity) and neutral (NEU; 19 °C; 39% relative humidity) temperatures. Exercise consisted of 25 min cycling at 70% LT and 25 min at 90% LT. In situ SCAAT lipolysis and blood flow were measured via microdialysis. Heart rate, core temperature, carbohydrate and fat oxidation, blood glucose, and blood lactate were also measured. Heart rate, core temperature, oxygen consumption, and blood lactate increased with exercise but were not different between COLD and NEU. SCAAT blood flow did not change from rest to exercise or between COLD and NEU. Interstitial glycerol increased during exercise (p < .001) with no difference between COLD and NEU. Fat oxidation increased (p < .001) at the onset of exercise and remained elevated thereafter with no difference between COLD and NEU. Carbohydrate oxidation increased with increasing exercise intensity and was greater at 70% LT in COLD compared to NEU (p = .030). No differences were observed between conditions for any other variable. Cycling exercise increased SCAAT lipolysis but not blood flow. Ambient temperature did not alter SCAAT metabolism, SCAAT blood flow, or fat oxidation in well-trained cyclists, though cold exposure increased whole-body carbohydrate oxidation at lower exercise intensities.

Performance analyses of basic cogeneration basic cogeneration plants in agriculture and food production

Energy in agriculture and in food production have vital importance that affect directly the cost and the quality of the products. Micro cogeneration plants are widely used in the World to produce heat and electricity at the same time in a same plant. The aim of this study, to analyze the performance of the production of power and heat for the food production process and the agricultural needs. For that reason, a basic cogeneration plant is taken to analyze the performance by using 1st and 2nd laws of thermodynamics and exergy analysis method. The electric-heat exergy rates, the energy and exergy efficiencies, the combustion chamber and the gas turbine outlet temperatures, the total electric and heat energies and exergies, and the specific works were calculated for various ambient temperatures and for various excess air rates of the basic cogeneration plants fueled with methane. The effects of the various ambient temperatures and the various excess air rates on the performance of the basic cogeneration plants were obtained, discussed and analyzed. For the best performance and for the best working conditions of the basic cogeneration plants in agriculture and food production process and food industry recommendations were done. It was found that, lower ambient temperatures give higher electric efficiency, but lower heat efficiency. However, an optimum excess air rates for the best performance was found at the value 2.3 of the excess air rates of the basic cogeneration plants fueled with methane.

Effects of Ambient Conditions on Helicopter Harmonic Noise Radiation: Theory and Experiment

The effects of ambient atmospheric conditions, air temperature, and density on rotor harmonic noise radiation are characterized using theoretical models and experimental measurements of helicopter noise collected at three different test sites at elevations ranging from sea level to 7000 ftabove sea level. Significant changes in the thickness, loading, and blade–vortex interaction noise levels and radiation directions are observed across the different test sites for an AS350 helicopter ying at the same indicated airspeed and gross weight. However, the radiated noise is shown to scale with ambient pressure when the flight condition of the helicopter is defined in nondimensional terms. Although the effective tip Mach number is identi ed as the primary governing parameter for thickness noise, the nondimensional weight coefficient also impacts lower harmonic loading noise levels, which contribute strongly to low-frequency harmonic noise radiation both in and out of the plane of the horizon. Strategies for maintaining the same nondimensional rotor operating condition under different ambient conditions are developed using an analytical model of single main rotor helicopter trim and confirmed using a CAMRAD II model of the AS350 helicopter. The ability of the Fundamental Rotorcraft Acoustics Modeling from Experiments (FRAME) technique to generalize noise measurements made under one set of ambient conditions to make accurate noise predictions under other ambient conditions is also validated.

Performance Optimization Analysis of An Air-source Heat Pump with Multi-Stage Waste Heat Recovery

In this paper presents the effect of different outdoor ambient temperatures and heating temperatures on the performance of an air-source heat pump drying system with multi-stage waste heat recovery has been analysed by recording actual operating status of the system for a little longer-term period. The results show that COP of the heat pump with any heat recovery mode will increase with heating temperature reduction or ambient temperature rising like that does it without heat recovery. As outdoor ambient temperature increasing, the suitable heat recovery mode to enhance COP of the heat pump drying system changes from mode 1-3 to mode 1-2-3 and then to mode 1-2. Especially outdoor low-temperature ambient conditions in winter, 1-3 under would both enhance COP and improve the problem of evaporator frost. But the waste heat utilization rate ηT of whole system is lowest. Moreover, it can be supposed by comparing η with ηT that the first-stage heat exchanger unit of the heat recovery system and the energy transfer fluid circulating in the system would be potential for optimization to further enhance the performance of whole air-source heat pump drying system.

Effects of Cyclic High Ambient Temperature on Muscle Imidazole Dipeptide Content in Broiler Chickens.

Imidazole dipeptides possess important bioregulatory properties in animals. This study aimed to evaluate the effect of high ambient temperature on muscle imidazole dipeptides (carnosine, anserine, and balenine) in broiler chickens. Sixteen 14-day-old male broiler chickens were divided into two groups, which were reared under thermoneutral (25 ± 1 °C) or cyclic high ambient temperature (35 ± 1 °C for 8 h/day) for 4 weeks. Chickens exposed to cyclic high ambient temperatures displayed lower skeletal muscle anserine and carnosine content than control chickens. Balenine could not be detected in the pectoral muscle of either group. The pectoral muscles of broiler chickens kept under cyclic high-temperature exhibited significantly lower mRNA expression of carnosine synthase 1, which synthesizes carnosine and anserine; but a significantly higher mRNA expression of carnosinase 2, which degrades carnosine and anserine. Our results suggest that heat exposure decreases pectoral imidazole dipeptide content in broiler chickens. This may be attributed to a lower expression of imidazole dipeptide-synthesizing genes, but higher levels of genes involved in their degradation.

Simulation of proton-induced primary displacement damage in GaAs under different ambient temperatures

The performance of on-orbit GaAs-based solar cells is susceptible to the displacement damage effect. The proton-induced primary displacement damage in GaAs on a geosynchronous equatorial orbit (GEO) was simulated and analyzed by combining the Monte Carlo (MC) and molecular dynamics (MD) methods. The MC simulation provided the distribution of primary knock-on atoms (PKAs) in GaAs induced by GEO-related protons to the MD simulation. In MD simulations, the effects of radiation fluence and ambient temperature on the displacement damage were considered. The simulation results showed that GEO-related protons generated a significant number of PKAs within an energy range of below 10 keV in GaAs. The high-fluence radiation emulated by the binary PKA could generate more point defects and cluster defects in GaAs than the low-fluence radiation emulated by single PKAs. As compared to room temperature (300 K), both a low (100 K) and high (500 K) ambient temperature could deteriorate the displacement damage. In addition, a high ambient temperature of 500 K could induce widespread thermal spikes in GaAs as compared to 100 and 300 K. This work can provide useful insight into the proton-induced displacement damage in GaAs and the radiation hardening of GaAs-based photoelectric devices in space.

Short-Term Effect of Ambient Temperature in Acute Ischemic Stroke with Endovascular Treatment Due to Large Vessel Occlusion.

Acute ischemic stroke (AIS) stands as the primary cause of mortality and extended disability globally. While prior studies have examined the connection between stroke and local weather, they have produced conflicting results. Our goal was to examine the correlation between temperature and functional prognosis in patients with large vessel occlusion (LVO) undergoing endovascular therapy (EVT). This study included a total of 1809 patients. Temperatures from stroke onset to groin puncture were categorized into Cold (10th percentile of temperature), Cool (10th-50th percentile of temperature), Warm (50th-90th percentile of temperature), and Hot (90th percentile of temperature) groups. The primary efficacy result was the modified Rankin Scale (mRS) score at 90 days. Safety outcomes included mortality, symptomatic intracranial hemorrhage (sICH) and complications after cerebral infarction. The primary efficacy results demonstrated a statistical enhancement in functional outcomes at 90 days for patients in the Warm group compared to the Cold group (adjusted common odds ratio [OR]: 1.386; 95% confidence interval [CI]: 1.024-1.878, P=0.035). Secondary efficacy results showed that temperature was associated with a higher rate of 90-day functional independence (adjusted OR: 1.016; 95% CI: 1.004-1.029; P=0.009), which was higher in the Warm group compared with patients in the Cold group (adjusted OR: 1.646; 95% CI: 1.107-2.448, P=0.014). There were no significant differences between groups in terms of sICH, 90-day mortality, and post-infarction complications. Compared with Cold temperature, Warm temperature is associated with better functional outcomes and reduced mortality risk without increasing the risk of sICH.

Benefits of watermelon juice and ascorbic acid supplementation on Institut de Sélection Animale brown layers managed under hot climate

Loss of homeostasis and poor egg production are common in laying hens during hot season. These negative effects of extreme ambient temperature have resulted in great economic losses to poultry farmers in the tropical regions. This study investigated benefits of supplementing watermelon juice (WJ) and ascorbic acid (AA) to ISA Brown (IB) hens managed under hot climate on productive performance and some hormonal responses. Ninety-six IB pullets aged 34 weeks were randomly allotted to four groups (C, T1, T2, and T3), each containing 24 in triplicates. The control group (C) was given water with neither WJ nor AA. Water given to groups T1, T2 was supplemented with 20% and 40% WJ, respectively, while T3 was supplemented with 200mg AA/litre of water. The results show a significant (P≤0.05) increase in water intake in T3 compared to other groups. Total egg production, daily egg production and hen-day egg production were significantly (P≤0.05) improved by the supplements, as total egg weights improved in T1:(272.2 ± 35.16g) and T2:(272.1 ± 35.06g) compared to C:(212.2 ± 25.06g) and T3:(238.5 ± 19.23g). The supplements caused 24.46%, 22.70% and 9.43% rise in percentage egg production in groups T1, T2, and T3 respectively. Serum corticosterone (C:10.88 ± 1.12; T1:10.20 ± 1.06; T2:9.61 ± 0.792; T3:7.23 ± 2.36ng/mL) and thyroxine levels (C:1.45 ± 0.562; T1:0.41 ± 0.109; T2:0.39 ± 0.367; T3:0.60 ± 0.489μg/dL) decreased significantly (P≤0.05) in supplemented layers, while serum prolactin and triiodothyronine differed non-statistically. In conclusion, WJ and AA supplementation ameliorated heat stress in IB layers managed under hot climate as it significantly lowered corticosterone and improved egg production. Therefore, supplementing 20%, 40%WJ or 200mg AA/litre in water is recommended for managing heat stress in IB layer chickens

Short-term effects of ambient temperature on acute exacerbation of inflammatory bowel disease: A nationwide case-crossover study with external validation.

Inflammatory bowel disease (IBD) is an idiopathic inflammatory disorder characterized by chronic and relapsing manifestations. Several environmental factors are known as triggers for exacerbation of IBD. However, an association between exacerbation of IBD and ambient temperature is uncertain. This study aimed to estimate the risk of acute exacerbation of IBD due to ambient temperature. We performed a bidirectional case-crossover study using a nationwide claim data from South Korea. The external validation was conducted with a large prospective cohort in the United Kingdom. We confirmed significant associations between acute exacerbation of IBD and the short-term ambient temperature changes toward severe temperatures, in the cold weather (-19.4°C-4.3°C) (odd ratio [OR] = 1.13, 95% confidence interval [CI]: 1.13-1.14) and in the hot weather (21.3°C-33.5°C) (OR = 1.16, 95% CI: 1.15-1.17). However, the association was not significant in the moderate weather (4.3°C-21.3°C). The external validation suggested consistent results with additional elevation of acute exacerbation risk in the colder weather (-13.4°C to 2.6°C) (OR = 1.90, 95% CI: 1.62-2.22) and in the hotter weather (15.7°C-28.4°C) (OR = 1.41, 95% CI: 1.32-1.51). We observed and validated that the short-term ambient temperature changes were associated with acute exacerbation of IBD in the cold and hot weathers. Our findings provide evidence that temperature changes are associated with the acute exacerbation of IBD.

Effect of ambient temperature on wheel and rail wear: Development and validation of new laws

In this study, we extend the existing modeling approach for wear prediction by incorporating ambient temperature as a crucial factor. To investigate its influence, we conducted a series of wear tests under varying ambient temperatures and hardness ratios in a controlled laboratory environment. Based on the empirical findings, we propose novel wear laws and determine the corresponding coefficients for these formulas. To validate the efficacy of our proposed wear laws, we present a numerical example focused on an application in a railway metro line. By comparing the simulated results with field measurements, we establish the strong consistency between them. Furthermore, a sensitivity analysis is performed to comprehensively assess the impact of ambient temperature and hardness ratio on wear evolution.

The effects of input power and ambient temperature on the thermal performance of conical pin fin heat sink in natural convection

In the present study, thermal performance tests of horizontally oriented HSconical, HScross-cut, and HSflat with a base plate dimensions of 80*80*5 mm3 were performed in natural convection. The effects of ambient temperature (30 and 40 °C), input power (16.5 and 33 W), and conical pin fin geometry on the thermal performance of the HSs were investigated. The thermal resistance of the heat sinks decreases while the convective heat transfer coefficient, average surface temperature, and average junction temperature increase with increasing ambient temperature and input power. However, the Nusselt number increases with increasing ambient temperature for all HSs at 16.5 W, while the Nusselt number decreases with increasing ambient temperature at 33 W. The highest convective heat transfer coefficients are 32.17, 30.68, and 19.61 W/m2K for HSconical, HSflat, and HScross-cut at 33 W and 40 °C, respectively. The lowest thermal resistances are 2.75, 2.80, and 3.81 K/W for HSconical, HScross-cut, and HSflat at 33 W and 40 °C, respectively. Thermal resistances of HSconical and HScross-cut decreased by 27.78 % and 26.44 % at maximum and 27.06 % and 24.58 at minimum, respectively, compared to HSflat. The results show that the conical fins have better thermal performance in natural convection.

Ethanol Inhomogeneous Lean Combustion Under Different Ambient Temperatures and Pressures with Hydrogen Enrichment

ABSTRACT The effects of different ambient temperatures and pressures on the combustion of hydrogen-enriched liquid ethanol spray were studied in a constant-volume vessel, using experimental and numerical methods. The inhomogeneous combustion experiment was conducted under ultra-lean conditions at an overall equivalence ratio of 0.3 (33% spray ethanol/67% premixed hydrogen). The spray and flame images and combustion pressures were obtained. The spray simulation models used were the RANS k-ε turbulence model, KH-RT model, and wall film interaction model. The experimental results showed that the inhomogeneous combustion of the liquid ethanol spray can be divided into two stages: a rapid-burning and a slow-burning stage. The slow-burning stage was sensitive to changes in ambient temperature and pressure. Combustion duration decreased with elevated pressure and declined temperature. Under low pressure and medium temperature conditions, the flame reached its fastest propagation speed. The simulation results showed that the fuel concentration and concentration gradient around the ignition position are the key factors that affect inhomogeneous lean combustion. When the equivalence ratio was over 0.8 around the ignition position and the gradient of the equivalence ratio increased no less than 0.1/mm, the optimal combustion characteristics were achieved.

Development and performance evaluation of online monitors for near real-time measurement of total and water-soluble organic carbon in fine and coarse ambient PM

In this study, we developed two online monitors for total organic carbon (TOC) and water-soluble organic carbon (WSOC) measurements in fine (dp < 2.5 μm) and coarse (2.5 μm < dp < 10 μm) particulate matter (PM), respectively. Their performance has been evaluated in laboratory and field tests to demonstrate the feasibility of using these monitors to measure near real-time concentrations, with consideration of their potential for being employed in long-term measurements. The fine PM collection setup was equipped with a versatile aerosol concentration enrichment system (VACES) connected to an aerosol-into-liquid-sampler (AILS), whereas two virtual impactors (VIs) in tandem with a modified BioSampler were used to collect coarse PM. These particle collection setups were in tandem with a Sievers M9 TOC analyzer to read TOC and WSOC concentrations in aqueous samples hourly. The average hourly TOC concentration measured by our developed monitors in fine and coarse PM were 5.17 ± 2.41 and 0.92 ± 0.29 μg/m³, respectively. In addition, our TOC readings showed good agreement and were comparable with those quantified using Sunset Lab EC/OC analyzer operating in parallel as a reference. Furthermore, we conducted field tests to produce diurnal profiles of fine PM-bound WSOC, which can show the effects of ambient temperature on maximum values in the nighttime chemistry of the winter, as well as on increased photochemical activities in afternoon peaks during the summer. According to our experimental campaign, WSOC mean values during the study period (3.07 μg/m³ for the winter and 2.7 μg/m³ for the summer) were in a comparable range with those of earlier studies in Los Angeles. Overall, our results corroborate the performance of our developed monitors in near real-time measurements of TOC and WSOC, which can be employed for future source apportionment studies in Los Angeles and other areas, aiding in understanding the health impacts of different pollution sources.

Energy and economic analysis of a sub-cooler based vapor injection transcritical CO2 heat pump for space heating

The Chinese government has considered the transcritical CO2 heat pump (TCHP) as a promising solution for space heating with the goal of “carbon peaking” and “carbon neutrality.” Considering the convenient implementation and the performance improvement, the vapor injection technique should be taken into consideration. This paper presents the experimental and simulation investigation of the SCVI TCHP prototype with energetic and economic analysis. Under the design condition, the SCVI technique could improve the peak COP by 5.02 % with a 10.11 % improvement in heating capacity. Compared to the direct electric heater solution, the annual operation cost was reduced by 11966CNY, 29.03 % higher than the Base TCHP. The payback period was decreased from 8 to 6.9 years due to the application of vapor injection. The effect of ambient temperature on the system performances was evaluated based on the experimental data. As the simulation progressed, a control strategy optimizing both the discharge and the medium pressure was developed, and the influence of inlet and outlet water temperature was studied.

Study on early shrinkage and cracking of slab in UHPC light-weight composite deck based on ambient temperature and humidity effects

This study investigates the early performance and potential issues of ultra-high-performance concrete (UHPC) light-weight composite decks (LCBDs) used in municipal highway bridge design. The major objective of this research was to understand the complex evolution of temperature and humidity within immature UHPC thin layers, which can lead to deformation and secondary stress, potentially causing cracks and threatening the long-term applicability and safety of steel-concrete composite bridges. Understanding of the mechanism of this process will be the basis for subsequent work. The early performance of UHPC with ordinary concrete is compared. Besides, discussions are conducted on the basic thermal conductivity theory of three-dimensional porous media and the hydration mechanism of cement-based materials that are appropriate for early-stage UHPC. Subsequently, a refined thermo-mechanical coupling analysis method for steel-UHPC LCBD was proposed, implemented using ABAQUS, and validated through a UHPC composite beam test. This method was applied to calculate the early shrinkage of the UHPC layer in a steel-UHPC LCBD and evaluate the risk of cracking in an actual bridge expansion project, providing a rationality evaluation of a bridge design and its construction procedure.