Ambient Temperature Variations Research Articles

Supramolecular Luminescent Hydrogel Based on Glycine/Terbium Complex and Fluorescent Dyes for Visual Temperature Monitoring

AbstractThe development of smart synthetic materials that are sensitive, accurate, and visually responsive to changes in temperature is vital. Herein, a supramolecular luminescent hydrogel based on a glycine/terbium (Gly/Tb) complex, rhodamine B (RB), and gelatin is reported. The hydrogel exhibits responsive luminescence and undergoes a temperature‐induced phase transformation from hydrogel to sol. The electrospray ionization time‐of‐flight mass spectra, Fourier‐transform infrared spectra, and simulation results verifiy the coordination mode of the Gly/Tb complex. The Gly/Tb complex and RB emit green and orange luminescence, respectively. When the Gly/Tb complex and RB are co‐doped into the gel network of gelatin, the obtained Gly/Tb/RB hydrogel displays steady yellow luminescence by virtue of luminescence resonance energy transfer. Subsequently, a luminescent switch is constructed owing to the sensitive and reversible luminescence responsiveness of the Gly/Tb/RB hydrogel to temperature stimuli. Remarkably, the Gly/Tb/RB hydrogel undergoes a visual phase transformation from hydrogel to sol above 35 °C, allowing the ambient temperature variation to be monitored. This study establishes a novel and effective route for the construction of smart optical materials and visual temperature monitors.

SKYQUANT 3D: Quantifying Vascular Anatomy With an Open-Source Workflow for Comprehensive Analysis of Volumetric Optoacoustic Angiography Data.

Efficient visualization of the vascular system is of key importance in biomedical research into tumor angiogenesis, cerebrovascular alterations, and other angiopathies. Optoacoustic (OA) angiography offers a promising solution combining molecular optical contrast with high resolution and deep penetration of ultrasound. However, its hybrid nature implies complex data collection and processing workflows, with significant variability in methodologies across developers and users. To streamline interoperability, we introduce SKYQUANT 3D, a Python-based set of instructions for the Thermo Fisher Scientific Amira/Avizo 3D Visualization & Analysis Software. Our workflow simplifies the batch processing of volumetric optoacoustic angiography images, extracting meaningful quantitative information while also providing statistical analysis and graphical representation of the results. Quantification performance of SKYQUANT 3D is demonstrated using functional preclinical and clinical in vivo 3D OA angiographic tests involving ambient temperature variations and repositioning of the imaged limb.

Studying the effect of ambient temperature variations on perovskite precursor film formation using different antisolvents

This study investigates the sensitivity of two antisolvents to ambient temperature fluctuations during the fabrication of triple-cation perovskite thin films. Chlorobenzene (CB) and ethyl acetate (EA) were employed as antisolvents in the preparation of perovskite solar cells (PSCs) under identical ambient temperature variation conditions. The experimental results reveal that the quality of the perovskite films does not exhibit a consistent trend in response to ambient temperature changes depending on the antisolvent used. When CB was used as the antisolvent, the highest-performing device, produced at an ambient temperature of 18 °C, achieved a power conversion efficiency (PCE) of 19.9 %. In contrast, when EA was employed as the antisolvent, the highest-performing device was fabricated at 25 °C, reaching a PCE of 20.5 %. Furthermore, when the ambient temperature exceeded 30 °C, all films prepared with either antisolvent exhibited significant cracking, indicating that elevated temperatures adversely affect perovskite film formation. To further investigate the mechanism through which ambient temperature affects the film-forming process, antisolvents at varying temperatures were used during perovskite film preparation to simulate transient temperature increases during formation. This study reveals that the impact of ambient temperature variations on perovskite film formation does not exhibit a uniform trend but is significantly influenced by the choice of antisolvent. Moreover, this work offers valuable insights for optimizing the fabrication of high-quality perovskite thin films.

A comprehensive study of gate-induced drain leakage current and electrical characteristics in nanosheet field-effect transistors due to variation in structural parameters and ambient temperature

Abstract IIn this paper, two substrate optimization approaches of triple stacked Nanosheet FET (SNSHFET), namely optimization of buried oxide and selective deposition of punch through stopper (PTS) substrate, have been examined and simulations have been carried out using Technology Computer-Aided (TCAD) software. A comprehensive study of leakage current and key electrical characteristics (I¬ON, VT, SS, DIBL) have also been extracted based on variation in temperature from 298 K to 450 K, sheet width, fin pitch, substrate width, and source/drain doping, as well as different substrates. When the ambient temperature of SNSHFET is varied from 298 K to 450 K, the gate-induced drain leakage (GIDL) current increases and degrades the VT and ION/IOFF ratio. GIDL current also increases with increased doping of the source and drain. Also, the impact of ultra-thin body substrate in SNSHFET is studied for the reduction in GIDL current and optimization in the performance. It is observed that a reduction in the substrate width and the nanosheet width decreases the GIDL current, while variation in Inter-fin pitch has no significant impact on the GIDL current and other electrical characteristics. The band-to-band tunneling rate and electric field profiles are observed at the channel-drain and gate-substrate overlap region for understanding the physical insights of leakage current in the SNSHFET. This work also answers the dependency of GIDL current on the gate and drain voltage supply respectively. In addition to that, how GIDL current responds to the variation in the source-drain doping and with different PTS doping has been explained. The 3 nm-based SNSHFET is designed and its electrical and GIDL characteristics are compared with novel devices like Forksheet FET and Complementary FET.

A novel heating system of solar-assisted enhanced jet enthalpy air source heat pump for cold regions

Solar energy and air source heat pumps are common heat sources for clean heating, but at lower ambient temperatures, the performance of solar energy and air source heat pumps will decline significantly, which can be ameliorated by integrating the two heat sources. However, the range of solar radiation and ambient temperature variation is very wide, and the existing integration methods cannot guarantee that they are optimal over a wide range. Therefore, this paper proposes a novel integration method of solar energy and jet enthalpy air source heat pump suitable for cold regions, where solar energy is used to heat the refrigerant in the jet branch to increase the flow rate of the jet branch, which enhances the effect of jet enthalpy. Under varying outdoor temperatures and solar radiations, the performances of the new integrated system and the traditional integrated systems are compared by simulation method. The results show that within the scope of this study (outdoor temperatures ranging from −30 °C to 10 °C, and radiations from 200 to 800 W/m2), the heat output and coefficient of performance of the new system are higher than those of the existing integrated systems. At an outdoor temperature of −30 °C and a radiation of 500 W/m2, the new system increases heat output by 45.8 % and coefficient of performance by 22.5 % compared with the existing two systems. This research can promote the application of solar energy and air source heat pump heating in cold regions.

The effects of ambient temperature on non-accidental mortality in the elderly hypertensive subjects, a cohort-based study

BackgroundThe association between ambient temperature and mortality has yielded inconclusive results with previous studies relying on in-patient data to assess the health effects of temperature. Therefore, we aimed to estimate the effect of ambient temperature on non-accidental mortality among elderly hypertensive patients through a prospective cohort study conducted in northeastern China.MethodsA total of 9634 elderly hypertensive patients from the Kailuan research who participated in the baseline survey and follow-up from January 1, 2006 to December 31, 2017, were included in the study. We employed a Poisson generalized linear regression model to estimate the effects of monthly ambient temperature and temperature variations on non-accidental mortality.ResultsAfter adjusting for meteorological parameters, the monthly mean temperature (RR = 0.989, 95% CI: 0.984–0.993, p < 0.001), minimum temperature (RR = 0.987, 95% CI: 0.983–0.992, p < 0.001) and maximum temperature (RR = 0.989, 95% CI: 0.985–0.994, p < 0.001) exhibited a negative association with an increased risk of non-accidental mortality. The presence of higher monthly temperature variation was significantly associated with an elevated risk of mortality (RR = 1.097, 95% CI:1.051–1.146, p < 0.001). Further stratified analysis revealed that these associations were more pronounced during colder months as well as among male and older individuals.ConclusionsDecreased temperature and greater variations in ambient temperature were observed to be linked with non-accidental mortality among elderly hypertensive patients, particularly notable within aging populations and males. These understanding regarding the effects of ambient temperature on mortality holds clinical significance for appropriate treatment strategies targeting these individuals while also serving as an indicator for heightened risk of death.

Cascade amplification-based triple probe biosensor for high-precision DNA hybridization detection of lung cancer gene

As an essential biomarker for diagnosing and treating various diseases, low-cost, quantitative detection methods for complementary DNA (cDNA) have received much attention. The surface plasmon resonance (SPR) sensing technique is an effective measurement scheme, but the ambient temperature and pH variations have a non-negligible impact. In this work, we developed a triple-probe SPR sensing system for detecting cDNA concentration, temperature, and pH. In order to satisfy the triple parameter measurements, we used a microstructured optical fiber as the sensing platform, silver and gold films as the excitation layer, and a MoS2 film as the modulation layer. First, we explore the modulation mechanism of SPR and the conditions for excitation of triple SPR and demonstrate that the carrier concentration is a crucial factor affecting the resonance wavelength. Then, the feasibility of the sensing system for triple-probing is theoretically analyzed. Finally, in the experiment, the optimal parameters of the sensor were determined, and the triple parameter detection was successfully realized. The experimental results show that the three probes can work independently, and the hybridized DNA probe can realize the selective detection of cDNA with a sensitivity of 0.249 nm/(nmol/l). The maximum sensitivity of the pH probe and the temperature probe are 51.5 nm/pH and 6.14 nm/°C. In addition, the experimental results show that the sensing probes have excellent reproducibility. This paper’s innovation is using the fiber optic SPR effect to achieve quantitative detection for cDNA, temperature detection, and pH detection. Therefore, the sensor has a promising future in early diagnosis and biosensing.

High frequency monitoring of carbon (iv) oxide evolution from a tropical soil amended with organomineral fertilizer in a screenhouse Ile-Ife, Nigeria

The study compared responses of carbon (iv) oxide evolved from an Ultisol sampled at different time scales and the soil properties when amended with organomineral fertilizer (OMF); thus tracking the carbon footprint of the amendment in ambient air. The carbon (iv) oxide efflux was measured titrimetrically in a static chamber set up in a screenhouse at sub-daily, daily and weekly time scales. At the same time, the antecedent soil properties were determined using standard methods. The treatments involved OMF addition at three rates (0 kg OMF, 40 kg Urea-N + 2.5 tons/ha organic fertilizer and 40 kg Urea-N + 5 tons/ha organic fertilizer) based on some Nigerian indigenous vegetable nutrient requirements. The result showed that a more detailed and accurate understanding of CO2 evolution processes was revealed at daily sampling resolution while sub-daily variation occurred in response to sub-daily variation in ambient temperature. Organomineral fertilizer at 40 kg/ha Urea + 2.5 tons/ha OF rate was comparatively safer in C management through the reduction in the CO2 released thus constituting a better alternative in terms of the greenhouse effect. Thus, the study recommends at least daily monitoring for a detailed understanding of CO2 evolution dynamics and management and identifies OMF rate with less CO2 release as a comparatively better alternative in the production of those vegetables in the environmental context.

Thermal response color-tunable electroluminescent device for real-time visual temperature monitoring

Alternating current electroluminescent (ACEL) devices have attracted tremendous attention due to their significant applications in bioinspired electronics, smart wearables, and human-machine interfaces. However, it still faces limitations in real-time visual temperature sensing. Herein, a universal strategy is established to achieve real-time temperature dynamic visualization by integrating a thermochromic layer through a simple spin coating procedure. Such elaborate integration permits the device to display a wide array of luminous colors and achieve high-contrast color transitions in response to ambient temperature variations. More importantly, a quantitative relationship can be established between the temperatures and the luminous color changes. This advancement not only enhances multi-color emission capabilities but also enables the display of diverse information, marking a significant stride in the development of dynamic temperature sensing in ACEL devices.

Modelling In Situ Concrete Temperature Development: The Impact of Ambient Temperature and GGBS Replacement

The rise in early-age temperature concrete structures, driven by the exothermic reactions during cement hydration, significantly increases the risk of thermal cracking. To address this issue, the construction industry employs several strategies, including the partial substitution of cement with ground granulated blast furnace slag (GGBS) due to its lower heat of hydration. Accurately predicting the hydration temperature of concrete is critical for preventing thermal cracking. This task becomes more complex, with fluctuating ambient temperatures influencing hydration kinetics and heat dissipation. Previous studies often assume adiabatic or isothermal conditions, thus overlooking the impact of ambient temperature variations. This paper presents an innovative finite element modelling (FEM) approach to simulate the hydration temperature progression in in situ concrete slabs, incorporating the effects of ambient temperature fluctuations. Isothermal calorimetry curves were adjusted using the Arrhenius-based approach to express the cement hydration rate as a function of ambient temperature. The FEM outcomes, validated with semi-adiabatic calorimetry tests, demonstrate the model’s capability to forecast temperature development in in situ concrete under varying ambient conditions. Additionally, the study examines the influence of partial cement replacement with GGBS on thermal behaviour, revealing that while GGBS effectively reduces thermal reactions at higher contents, its efficacy diminishes with rising ambient temperatures.

Off-design operation and performance of pumped thermal energy storage

In this article, we describe off-design models and control strategies for a Pumped Thermal Energy Storage (PTES) system that uses liquid thermal energy storage: specifically molten salt for hot storage and methanol for cold storage. Off-design conditions arise when load-following, or due to variations in storage tank temperatures or ambient temperatures. We propose a control strategy that uses inventory control to manage the mass flow rate in the thermodynamic cycles, which facilitates load following. We also propose a control strategy for the storage fluid mass flow rates, which are varied to ensure the molten salt is maintained at its design temperature. This maximizes efficiency and minimizes problems with salt freezing or degradation. The cold storage fluid mass flow rate is varied so that the cold tanks have the same state-of-charge as the hot tanks. This leads to variations in cold fluid temperature, but these variations are shown to be acceptably small (e.g. 7.5 % increase), and this control method is shown to be simpler and more efficient than an alternative strategy where tanks become unbalanced. The ambient temperature and storage tank temperatures are moved ±50 °C from the design values and the impact on power, duration, and tank temperatures is quantified. Results demonstrate that the proposed control strategy is stable and self-correcting – that is, storage temperatures converge on stable values after two-to-three charge-discharge cycles. When inputs return to design values, the system returns to its design point after two charge-discharge cycles. We also demonstrate that inventory control enables delivery of the target power output even when off-design conditions exist that would normally reduce the power output.

Design and Preparation at Scale of Ternary NiFe-M-Ox (M=Co, Mo) Catalysts for OER in Alkaline Media

Due to scarcity of Platinum Group Metals (PGMs) widely used in low temperature water electrolysis as cathodes (Hydrogen Evolution Reaction; HER) and anodes (Oxygen Evolution Reaction; OER) a boosting interest to their substitution to Earth abundant elements is observed. It was successfully demonstrated that elements like iron, nickel, cobalt and other (in their oxide and hydroxide forms) can be effective OER catalysts when operate at high pH ranges from 12 to 14 [1-3].This work is devoted to systematic investigation of influence of third element addition to NiFeOx system on a performance and stability of catalysts in alkaline OER. As a co-catalytic elements Mo and Co were selected, based on our previous experience [4,5]. A systematic study on an effect of NiFe-to-M ratio, concentration of precipitation agent and post-treatment temperature were evaluated in a wide range of parameters. Taking into account that mass loading of PGM-free OER catalysts is substantially higher than iridium/ruthenium once and can be up to several milligrams per cm2 all experiments were designed to be scalable. In a laboratory scale reactor, a fascinating batch size of 25g was achieved, using minimal amount of water-based solvents in order to minimize a waste stream generated. Presentation will discuss characterization of obtained materials by SEM, TEM, XPS, XRD and other methods as well as their performance, stability and durability in alkaline conditions, studying Oxygen Evolution Reaction. Acknowledgements and Statements. The authors acknowledge financial support from H2NEW and ElectroCat consortia. References. [1] X. Lyu, J. Li, J. Yang, A. Serov "Significance of Slight Ambient Temperature Variation on the Electrocatalyst Performance toward Oxygen Evolution Reaction" Journal of Environmental Chemical Engineering (2023).[2] X. lyu, A. Serov “Cutting-edge methods for amplifying the oxygen evolution reaction during seawater electrolysis: a brief synopsis” Ind. Chem. Mater., (2023).[3] X. Lyu, Y. Bai, J. Li, R. Tao, J. Yang, A. Serov "Investigation of oxygen evolution reaction with 316 and 304 stainless-steel mesh electrodes in natural seawater electrolysis" J. of Environmental Chemical Engineering 11 (2023) 109667.[4] A. Serov,N. I. Andersen, A. J. Roy, I. Matanovic, K. Artyushkova, P. Atanassov “CuCo2O4 ORR/OER Bi-Functional Catalyst: Influence of Synthetic Approach on Performance”, J. of The Electrochem. Soc. 162 (4) (2015) F449-F454.[5] N. I. Andersen, A. Serov, P. Atanassov “Metal Oxides/CNT Nano-Composite Catalysts for Oxygen Reduction/Oxygen Evolution in Alkaline Media”, Appl. Catal. B: Environmental 163 (2015) 623-627.

Regulation of Intrinsic Defects of Self‐Activated MgGa2O4 Phosphors for Temperature Dynamic Anti‐Counterfeiting

AbstractPhotoluminescent (PL) anti‐counterfeiting plays a critical role in encrypted information and anti‐counterfeiting. Dynamic PL anti‐counterfeiting technology provides advanced security features compared with static counterparts. Yet, many current dynamic luminescent materials rely solely on an optical storage mechanism, leading to a lack of diversification and making them vulnerable to replication. Here, dynamic PL emission triggered by ambient temperature variations is addressed. By modifying the sintering atmospheres and non‐stoichiometric ratio of MgGa2O4 (MGO) samples, the concentration of intrinsic defects of the host are modified, resulting in temperature‐sensitive PL output dynamically manipulated from blue to green to red. Density‐functional theory (DFT) analysis elucidates the formation energies of intrinsic defects in the MGO samples, revealing that the self‐activated blue, green, and red emissions stem from lattice defects, [GaO6], antisite defects , and interstitial oxygen (), respectively. Additionally, by monitoring the luminescence lifetime, and the thermoluminescence (TL) curves of the MGO samples, it is shown that the dynamic PL emission is generated by a combination of thermally assisted carrier migration and thermal compensation from trapping centers. Herein, a dual‐channel encrypted dot matrix is designed to enhance information transfer security through the interference between the dual channels, showcasing the practical application of this dynamic anti‐counterfeiting technique.

Development of S-domain experimental correlation thermal control model and rapid enumeration PID tuning method for uncooled Laser chip module

Uncooled semiconductor lasers are sensitive to ambient temperature variation which makes the PID thermal control for the uncooled semiconductor is complicated. In this work, a kind of enumeration PID tuning method based on S-domain experimental correlation thermal control model for the uncooled semiconductor lasers is introduced. Numeric validation and enumeration PID tuning of S-domain experimental correlation model for uncooled semiconductor are conducted. Results shows that the control accuracy prediction result of the S-domain experimental correlation model has a deviation of 3.6% in contrast with CAE simulation result. The PID tunning speed of rapid enumeration S-domain experimental correlation method is 17,000 times that of CAE method.

Optimising design and operation of sewage source heat pump: techno-economic and environmental assessment

ABSTRACT Heat pump can be used to recover abundant thermal energy contained in the discharge of municipal wastewater treatment plants. While there are some design standards for common heat pump systems, the design of a sewage source heat pump (SSHP) system is still often based on a fixed heat load and neglects the interdependencies between the equipment sizing and operating parameters. To address the issue that previous design methods have not balanced investment and operational costs well from a global optimisation perspective, this work formulates the simultaneous optimisation of SSHP design and operation as a non-linear programming problem. The proposed model features the consideration of multiple working conditions caused by the impact of ambient temperature variation on the heat load of the SSHP system. The feasibility and potential benefits of the optimised SSHP system are also evaluated by incorporating techno-economic performances and environmental impact analyses into the mathematical framework. A case study is carried out to demonstrate the effectiveness of the proposed methodology. The results show that the total annual cost of the optimally designed and operated SSHP in Harbin could be 9% lower than in Beijing and 39% lower than in Shanghai, suggesting that constructing and running the SSHP system in severe cold regions with great heating demands might be more economical than in less cold regions. The CO2, SO2, and NOx emissions of the SSHP could be approximately 50% less than that of coal-fired boiler heating, and 80% less than that of direct electric heating with coal-fired electricity.

Relative intensity noise management and thermal/shot noise control for high speed ultra high bandwidth fiber reach transmission performance

Abstract This work has clarified the relative intensity noise management and thermal/shot noise control for high speed ultra high bandwidth fiber reach transmission performance. Total link losses variations are clarified against ambient temperature and relative refractive index difference variations at 1,550 nm wavelength, 20 km fiber link length, and 45 % fluoride dopant ratio inside the fiber material cable. Besides the total link losses variations are demonstrated versus fiber link length and relative refractive index difference variations at 1,550 nm wavelength, room temperature, and 45 % fluoride dopant ratio inside the fiber material cable. Required optical signal per noise ratio (OSNR), electronic signal to noise ratio (SNR), and optimum gain variations are measured and analyzed versus the fiber link length and relative refractive index difference variations at 1,550 nm wavelength, room temperature, and 45 % fluoride dopant ratio inside the fiber material cable.

Energy- efficient cementitious mortar containing clay based shape-stable phase change material: Development, characterization and temperature controlling performance

The need for buildings to ensure a comfortable thermal environment is increasing, leading to a surge in energy consumption. This study proposes an innovative approach to tackle thermal energy storage challenges in buildings by formulating a unique cementitious mortar containing a shape-stable composite of Saudi Arabian natural clay and methyl stearate phase change material (PCM). The inclusion of natural clay, chosen for its cost-effectiveness and eco-friendliness, addresses the issue of methyl stearate leakage—a common concern with PCM usage. Despite PCM incorporation, the mixture maintains desirable fluidity and consistency, albeit with a slightly reduced dry unit weight and compressive strength. Differential scanning calorimetry analysis defines key characteristics of the resulting shape-stable NC/MS composite PCM, including a melting point of 33.81°C and a latent heat storage capacity of 56.15 J/g. Empirical testing demonstrates the efficacy of the natural clay/PCM composite in temperature moderation. During periods of elevated external temperatures, the NC/PCM specimen effectively lowers room-center temperatures by up to 4°C and sustains a cooler environment compared to the control room for almost 8 hours. Additionally, the composite PCM limits the maximum increase in room center temperature post-sunset to only 2.49°C, showcasing its capability in stabilizing indoor temperatures. This innovative PCM composite responds dynamically to ambient temperature variations, transitioning between solid and liquid states to release stored latent heat, consequently reducing building heating and cooling loads, enhancing energy efficiency. The natural clay/PCM composite presents a promising solution for advancing building thermal energy storage systems, aligning with energy efficiency and sustainable design objectives.

Meteorological factors and risk of ischemic stroke, intracranial hemorrhage, and subarachnoid hemorrhage: A time-stratified case-crossover study.

Stroke risks associated with rapid climate change remain controversial due to a paucity of evidence. To examine the risk of subarachnoid hemorrhage (SAH), intracranial hemorrhage (ICH), and ischemic stroke (IS) associated with meteorological parameters. In this time-stratified case-crossover study, adult patients hospitalized for their first stroke between 2011 and 2020 from the insurance claims data in Taiwan were identified. The hospitalization day was designated as the case period, and three or four control periods were matched by the same day of the week and month of each case period. Daily mean and 24-h variations in ambient temperature, relative humidity, air pressure, and apparent temperature were measured. Conditional logistic regression models were applied to assess the risk of stroke associated with exposure to weather variables, using the third quintile as a reference, controlling for air pollutant levels. There were 7161 patients with SAH, 40,426 patients with ICH, and 107,550 patients with IS. There was an inverse linear relationship between mean daily temperature and apparent temperature with ICH. Elevated mean daily atmospheric pressure was associated with an increased risk of ICH. A greater decrease in apparent temperature over a 24-h period was associated with increased risk of ICH but decreased risk of IS (odds ratio (95% confidence interval) for the first vs. third quintile of changes in apparent temperature, 1.141 (1.053-1.237) and 0.946 (0.899-0.996), respectively). There were considerable differences in short-term associations between meteorological parameters and three main pathological types of strokes. The authors have no permission to share the data.

Research on flammability of 3,3,3-trifluoropropene and its binary mixtures with flame retardants

3,3,3-trifluoropropene (R1243zf), which has good environmental and cycling characteristics, is a very promising fourth generation new working fluid. However, it is flammable, so studying its combustion characteristics and how to suppress its flammability are of great significance. Firstly, the flammability limits of three binary mixtures composed of a combustible substance (R1243zf) and three flame retardants (R245fa, R1216, and R13I1) were experimentally studied. The results showed that as the proportion of flame retardants increased, the lower flammability limit of the mixture increased, while the upper flammability limit decreased except for R245fa. The critical suppression ratios of R245fa, R1216, and R13I1 on R1243zf were 4, 0.538, and 0.538, respectively. Then, the improved group contribution method was used to predict the minimum inhibitory concentration of R1243zf, with an error of only 4.57 % compared to the experimental values. Finally, the influence of variable ambient temperature (25–100℃) on the flammability of R1243zf was studied, and the calculated adiabatic flame temperature method was used to predict the flammability limit at different temperatures. The error between the predicted values and the experimental values is only 1.7 %. The relevant results are of great significance for the safe application of R1243zf and new binary mixed working fluids.

Optimal allocation of solar photovoltaic distributed generation for performance enhancement of electrical distribution networks considering optimal volt‐var regulation under uncertainty and high load variation

AbstractThis article proposes an optimal placement and sizing of photovoltaic (PV) power systems based distributed generation (DG) in radial electrical distribution networks considering the capability of PV inverters to regulate the voltage by optimal injecting and absorbing reactive power at the point of common coupling (PCC) using honey badger algorithm (HBA), as a recent and efficient optimization algorithm to solve the complicated optimal allocation. Several objective functions are achieved for distribution system performance enhancement: minimizing the power loss and the voltage deviation index (VDI) and maximizing the voltage stability index (VSI). Based on historical data and probabilistic models, seasonal hourly solar irradiance, ambient temperature, and load variation curves have been modeled, which simultaneously consider the light, normal, and heavy load demand. The essential components of distribution power systems have been characterized. To investigate the validity of the proposed approach, IEEE 33 and IEEE 69 BUS radial distribution test systems have been considered for power flow (PF) analyses, where Newton's Raphson method has been applied to solve the PF issue. The simulation results of different numerical scenarios have shown the effectiveness and validity of the newly proposed method to solve the optimal allocation problem considering optimal volt‐var regulation control of PV inverters compared to several valid and robust optimization algorithms.