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A multiple stream process (MSP) is a process at a point in time that generates several streams of output with quality variables and specifications that are identical in all streams. Statistical process control (SPC) schemes for MSPs are designed to issue an out‐of‐control (OC) signal when a possible change occurs from the in‐control (IC) state of the process. However, the SPM literature for MSPs lacks contributions regarding post‐hoc identification of the stream or group of streams responsible for an OC signal. In this article, we propose an artificial neural network (NN) specifically trained for this purpose and, through a Monte Carlo simulation, show its superiority in correctly identifying OC streams, since an OC signal has been correctly issued. The research is motivated by the need for a post hoc diagnosis of the heating, ventilation, and air conditioning (HVAC) systems installed on modern train coaches, generating multiple streams of quality variables of interest. A case study in this area based on the HVAC data (openly available online at https://github.com/unina‐sfere/NN4OCMSP) illustrates the practical applicability of the proposed approach, which is implemented in the Python package NN4OCMSP and published on the PyPI software repository. [ABSTRACT FROM AUTHOR]

Compared to organic–inorganic hybrid perovskite solar cells (PSCs), all inorganic CsPbBr3 perovskite solar cells have higher stability but lower efficiency. Owing to the low solid solubility of CsBr in methyl alcohol, an incomplete first-step reaction with PbBr2 reaction takes place at room temperature. As a result, a large amount of CsPb2Br5 is generated in the final CsPbBr3 film, which deteriorates the performance of CsPbBr3 PSCs. Along these lines, in this work, CsCl was added to increase the reaction between CsBr and PbBr2 in the first step and high-quality CsPbBr3 films were prepared without CsPb2Br5. Our analysis demonstrated that at the optimal CsCl concentration of 6% in CsBr solution, the CsPbBr3 perovskite solar cells exhibited a power conversion efficiency of 7.33%. The best device retained 98.57% of the power conversion efficiency (PCE) after storing it for 30 days under ambient air condition. [ABSTRACT FROM AUTHOR]

Many hydrofluorocarbon refrigerants used in air-conditioning and refrigeration equipment are being phased out based on international restrictions to reduce global warming. Over 1 billion kilograms of hydrofluorocarbons are in use, and recycling is imperative to preventing the release of these greenhouse gases into the atmosphere. We report on composite hollow fiber membranes that can efficiently separate a mixture of difluoromethane and pentafluoroethane that is used worldwide in air conditioners. Selective hollow fiber membranes have been fabricated with a single submicrometer coating of a copolymer of 70 mol % perfluoro(butenyl vinyl ether) and 30 mol % perfluoro(2,2-dimethyl-1,3-dioxole) that separates the azeotropic mixture into a permeate stream with a difluoromethane purity of >95 mol %. Rather than incinerating these valuable materials, this technology can be used to recycle nonregulated difluoromethane for future products and recover pentafluoroethane for use as a chemical feedstock, creating a circular economy. [ABSTRACT FROM AUTHOR]

In the second part of the paper, an experimentally validated extension of the mathematical model is presented to simulate the thermal behavior of a roll-bond parallel-plate evaporator under frosting. This novel heat exchanger geometry is a potential alternative to finned-tube "no-frost" evaporators in some applications. The experimental work consisted of testing one of the heat exchanger prototypes selected from Part I in a closed-loop wind tunnel calorimeter at different conditions of air temperature, humidity, air flow rate and inlet coolant temperature. The semi-analytical model divided the evaporator in control volumes involving the air, plate and coolant and solving the momentum, energy, and species balance equations to generate distributions of air humidity, temperature, and pressure, as well as frost thickness and aluminum plate temperature. A good agreement was observed for the heat transfer rate, mass of frost accumulated in the heat exchanger and pressure drop, as most data points were predicted to within ± 20% relative error. [ABSTRACT FROM AUTHOR]

Despite the recent rapid development in the organic–inorganic halide perovskite solar cells (PSCs), the crystalline stability of the perovskite (PVK) material, particularly of the MAPbI3, remains a significant impediment to PSC applications. We proposed that short-term ultraviolet (UV) irradiation under air conditions can stabilize the PVK phase and increases the film crystallinity. Detailed investigations indicated that the electrons can be released from the bridging hydroxyls (OHB) bonds under UV irradiation to generate a small amount of active oxygen (O2−) on the TiO2 film surface, forming stable Pb–O bonds and α phase PVK. A 25% increases in photovoltaic conversion efficiency with a considerable stability, and the device maintains over 90% efficiency after 400 h of storage in N2. This study provides a simple and effective method to produce efficient and stable PSC devices at low cost. [ABSTRACT FROM AUTHOR]

Enhanced heat and mass transfer in a falling film liquid desiccant dehumidifier is crucial for improving the efficiency of liquid desiccant air conditioning systems. However, no study has yet been undertaken to examine the impact of a range of different enhancing elements on dehumidification performance. This study comprehensively investigates and compares falling film hydrodynamics and dehumidification performance on plates with various enhancing elements based on different air inlet velocity and humidity, solution inlet velocity, and concentration, as well as enhancing element spacing and height. The results demonstrate that, under a variety of working conditions, the dehumidification performance of the plate with isosceles right triangle shaped finned elements (plate No. 3) is superior to that of other plates. The dehumidification performance of plates with finned elements is superior to that of plates with grooved elements under the same condition. For plates with isosceles right triangle shaped finned elements, the impact of the flow field caused by the elements is greater than in other shapes due to the greater intensity of the gas-liquid perturbation and mixing, resulting in an enhanced dehumidification performance. The findings of this study may prove valuable in the optimization of dehumidifier structures in the context of liquid desiccant dehumidification performance enhancement. [ABSTRACT FROM AUTHOR]

Previous studies generally focused on the indoor temperature of buildings and air supplies to their environment. The effect of outdoor pollutants on thermal conditions has also attracted some interest in recent years. However, the number of studies on other factors that may potentially affect thermal comfort and health in high-rise buildings is limited. A structured analytical hierarchy process and an improved data envelopment analysis method are used in this study to determine the indoor and outdoor spatial features and climatic effects that influence thermal comfort in multi-storey business buildings. The impact levels of these factors on thermal conditions are determined with heuristic algorithms. Further, two climate zones in two countries are compared in terms of the factors that affect thermal comfort and their individual impact levels. The most critical criterion for Kuwait is external insulation features, whereas for Turkey it is indoor air conditioning. The most critical sub-criterion is temperature for Kuwait, whereas for Turkey it is insufficient heat and light insulation of windows. Data envelopment analysis yields that respiratory health diseases are the most critical effect in Kuwait, and work accidents are the most important effect in Turkey. Temperature and humidity play a significant role in thermal comfort in Kuwait. Insulation and air conditioning are crucial factors in thermal comfort conditions in Turkey. [ABSTRACT FROM AUTHOR]

A new meteorological station (DMS) was established at the Morning Glory summit in Zhejiang Province to provide regional background information on atmospheric composition in the Yangtze River Delta (YRD) region, China. This study investigated the first carbon monoxide (CO) records at DMS from September 2020 to January 2022. The annual average concentration of CO was 233.4 ± 3.8 ppb, which exceeded the measurements recorded at the other Asian background sites. The winter CO concentration remained elevated but peaked in March in the early spring due to the combined effect of regional emissions within the YRD and transportation impacts of North China and Southeast Asia sources. The diurnal cycle had a nocturnal peak and a morning valley but with a distinct afternoon climb, as the metropolis in the YRD contributed to a local concentration enhancement. The back trajectory analysis and the Weighted Potential Sources Contribution Function (WPSCF) maps highlighted emissions from Anhui, Jiangxi, Zhejiang, and Jiangsu provinces as significant sources. Due to well-mixed air conditions and fewer anthropogenic influences, DMS records closely aligned with the CO averages derived from the Copernicus Atmospheric Monitoring Service (CAMS) covering the YRD, confirming its representativeness for regional CO levels. This study underscored DMS as a valuable station for monitoring and understanding CO spatiotemporal characteristics in the YRD region. [ABSTRACT FROM AUTHOR]

Radon is a naturally occurring radioactive gas that causes lung cancer. It has been measured extensively in homes and mines but research in other workplaces has been limited. The present study examined 453 workplaces in Ontario, Canada, to characterize radon levels. Radon monitors (n = 687) were placed in occupied ground floor and basement workplace locations for a minimum of three months. The radon measurements ranged from <4 to 566 Bq/m3, with a median of 26 Bq/m3, arithmetic mean of 40.2 Bq/m3, and geometric mean of 26.9 Bq/m3. Using the Health Canada and Ontario labor guideline of 200 Bq/m3, 2.5% of participating workplaces had at least one measurement above this level; 7.2% were above the World Health Organization guideline. Workplaces were also asked to fill out questionnaires to identify possible determinants of exposure. Radon levels varied significantly based on municipality and background radon zone, highlighting the importance of geography in influencing radon levels. Radon levels also varied significantly based on window-opening behavior, business access type, the presence of an elevator, air conditioning, additions to the building, and cracks and/or gaps in the foundation/wall and around drains, indicating building characteristics with some influence on air circulation may impact overall radon levels. [ABSTRACT FROM AUTHOR]

Air pollution is a major health-related environmental challenge that affects many aspects of people's daily lives. For amateur endurance athletes/exercisers, air pollution can cause, apart from the common health issues, reduced performance capacity during training and races. The most significant inconveniences that these amateur athletes/exercisers have to deal with, are related to breathing difficulty, increased heart rate, cough or respiratory problems, and eye or nose discomfort. The aim of this study is to create a psychometric scale that estimates the nuisance/discomfort that amateur endurance athletes/exercisers (triathlon, cycling, running, swimming) feel during their training, under conditions of increased air pollution, and to see how this is linked to demographic characteristics. The main overall purpose is the identification of possible correlation between air pollution and reduced athletic performance, as well as between air pollution and the wellbeing of amateur endurance athletes/exercisers, and to thus enable recommendations on training in a polluted environment. To this aim, a questionnaire was developed, initially through a pilot stage. The fully developed scale was provided to two hundred and ninety-two (292) amateur endurance athletes/exercisers for an exploratory factor analysis to be carried out. The exploratory factor analysis indicated three (3) factors accounting for 37.11% of the overall variance. The first factor "Physical discomfort" included nine (9) questions, the second factor "Lack of discomfort" five (5) questions, and the third factor "No general discomfort" six (6) questions. The degree of reliability was satisfactory, since Cronbach's a coefficient was 0.841 for the first factor, 0.642 for the second, and 0.766 for the third factor. Subsequently, fluctuation analysis (ANOVA), multivariate fluctuation analysis (MANOVA), and Pearson's r coefficient were used to indicate correlations between the independent variables and the three factors identified. Correlation between discomfort due to air pollution and the place of residence, as well as the presence or absence of allergies, was indicated. On the other hand, there were no significant statistical differences between gender, type of sport, the volume of training, the presence or not of respiratory problems, and smoking. Overall, the scale can be considered both valid and reliable. [ABSTRACT FROM AUTHOR]

This study proposes a control method that integrates deep reinforcement learning with load forecasting, to enhance the energy efficiency of ground source heat pump systems. Eight machine learning models are first developed to predict future cooling loads, and the optimal one is then incorporated into deep reinforcement learning. Through interaction with the environment, the optimal control strategy is identified using a deep Q-network to optimize the supply water temperature from the ground source, allowing for energy savings. The obtained results show that the XGBoost model significantly outperforms other models in terms of prediction accuracy, reaching a coefficient of determination of 0.982, a mean absolute percentage error of 6.621%, and a coefficient of variation for the root mean square error of 10.612%. Moreover, the energy savings achieved through the load forecasting-based deep reinforcement learning control method are greater than those of traditional constant water temperature control methods by 10%. Additionally, without shortening the control interval, the energy savings are improved by 0.38% compared with deep reinforcement learning control methods that do not use predictive information. This approach requires only continuous interaction and learning between the agent and the environment, which makes it an effective alternative in scenarios where sensor and equipment data are not present. It provides a smart and adaptive optimization control solution for heating, ventilation, and air conditioning systems in buildings. [ABSTRACT FROM AUTHOR]

PEMFCs' operation entails the presence of heterogeneities in the generation of current, heat and water along the active surface area. Indeed, PEMFCs are open systems, and as such, operating heterogeneities are inherent to their operation. A review of the literature reveals numerous attempts to achieve uniform current density distribution. These attempts are primarily focused on bipolar plate design and operating conditions, with the underlying assumption that uniform current density correlates with enhanced performance. Most studies focus on the influence of gas flow-field design and inlet hydrogen and air flow conditioning, and less attention has been paid to the coolant operating condition. However, uncontrolled temperature distribution over a large cell active surface area can lead to performance loss and localized degradations. On this latter point, we notice that studies to date have been confined to a narrow range of operating conditions. It appears that complementary durability studies are needed in order to obtain in-depth analyses of the coupled influence of temperature distribution and gas humidification in large PEMFCs. [ABSTRACT FROM AUTHOR]

The paper focuses on the simulation and testing of a hybrid solid desiccant‐vapor compression air‐conditioning system under different hot‐humid climates. The simulation is carried out by a BLUEJ programming framework. Air at the lowest achievable temperatures from a solid desiccant cooling system is supplied to a standard vapor compression air‐conditioning system (VCAS). The cooling capacities of the hybrid system under three modes 1, 2, and 3, indicating different supply air conditions to the cabin, are reported in the paper. This paper expresses the trade‐off between having comfort conditions and reasonable comfort conditions inside the cooling space with energy efficiency as the inflection point. The more the study is moved towards the point of energy efficiency, the higher the reduction in the cooling capacities of the vapor compression air conditioner. This is demonstrated by the cooling capacity savings when the system is operated in three modes namely 1, 2, and 3. The substantial energy savings provided by Mode 1, Mode 2, and Mode 3 are 71%, 57%, and 37%, respectively. If the system is made to provide substantial cooling and focuses deeply on cooling capacity savings, then the system could save up to 77% in the cooling capacity of the vapor compression air‐conditioning system. If the system is made to operate solely with the milestone of comfort cooling for the occupants with any substantial savings in the cooling capacity of the vapor compression air‐conditioning system, then Mode 3 would deliver the milestone and give savings in the cooling capacities from 32% to 41% which is a significant savings. From the results of the performance study, it is inferred that the hybrid system provides significant energy savings compared to a standard air conditioner, especially in hot‐humid ambient conditions. The solid desiccant cooling system thus establishes itself as an effective pre‐cooler unit for a VCAS. The hybrid solid desiccant air‐conditioning in the paper is analyzed from the aspects of savings in cooling capacities of an existing vapor compression air‐conditioning system and comfort cooling. This is a newer operational approach, especially for using this hybrid solid desiccant cooling system for ambient humidity ratios greater than 15 kg−1 d.a. [ABSTRACT FROM AUTHOR]

The air conditioning system is a very important energy-consuming device in the field of construction. Timely troubleshooting of air conditioning chillers is an important aspect of reducing building energy consumption. Aiming at the problems of many model parameters, large amount of calculation and strong dependence of diagnostic performance on input features in data-driven diagnostic methods, this paper proposes an efficient fault diagnosis strategy combining RepVGG network and SENet attention mechanism. The multi-parameter feature signal is converted into a two-dimensional matrix to obtain multiple feature images. Based on the SENet attention mechanism, the multi-channel weights of the images are extracted, and the weighted feature image is input into the RepVGG network for feature depth mining and classification. Therefore, the method proposed in this paper greatly reduces the calculation amount of parameters, improves the representativeness of signal features to faults and the efficiency of model training. The effectiveness of the method is validated using the ASHRAE RP-1043 chiller unit dataset. The results show that the accuracy of this method reaches 96.55%, which is significantly better than the comparison methods PSO-ELM(96.4%), DT(95.1%), RepVGG(91.6%), ELM(87.6%) and BP(80.8%). [ABSTRACT FROM AUTHOR]

The power consumed by air-conditioning systems (AC) in hot and dry climates can reach 60% of the generated energy. One important reason is the frequent over-sizing of heating ventilating, and air-conditioning (HVAC) systems. It is therefore essential to provide practitioners with simple, easy-to-use, yet accurate tools for estimating cooling loads. The Radiant Time Series (RTS) is a newer, more accurate method that is derived from the exact Heat Balance (HB) method. In this work, the procedure is programmed using several Matlab subroutines to furnish a collection of charts and tables that could be used by engineers and practitioners to accurately predict cooling loads for a variety of situations. These include a wide range of locales; external/internal and ventilation/infiltration loads; building constructions; internal heat gain (people, lighting, equipment, etc.); ventilation systems; and so on. In addition to charts and tables, the procedure can also generate sets of Cooling Load Temperature Difference, Solar Cooling Load, and Cooling Load Factor (CLTD/SCL/CLF) derived from the RTS, for any combination. Moreover, enhancements in the finite volume (FV) calculation procedure of the RTS conduction time series and radiant time factors were made. Results are presented, in graphical/tabular formats, ready to be used/read by practitioners with minimal to no effort. Examples of different climate types are given. The program provides good, inexpensive, and accurate load-estimates which help prevent both energy waste due to over-sizing as well as thermal discomfort due to under-sizing. [ABSTRACT FROM AUTHOR]

A hydraulic jump taking place in a partially filled pipe is responsible for rapid change in the pipeflow dynamics and air content. The pipeflow self-aeration at hydraulic jump in a closed pipe has not been studied in terms of detailed air–water flow structures. In this work, a dual-tip conductivity phase-detection probe was used to intrusively measure the air–water flow of hydraulic jumps in a horizontal enclosed circular pipe with controlled air supply. The hydraulic jumps exhibited highly three-dimensional roller structures in the circular pipe. The distributions of void fraction, particle count rate, and longitudinal velocity were obtained in the vertical plane along pipe axis, and the characteristic quantities were compared to the literature data of open-channel hydraulic jumps in rectangular flumes. The intrusive measurement was challenged by the unstable hydraulic jump positions in the pipe due to the finite air ventilation condition, and the variations in repetitive sampling results were assessed. The air–water flow property distributions were overall comparable to those in quasi-two-dimensional hydraulic jumps, except for full-pipe downstream flows with roller interaction with the pipe ceiling. The secondary surface roller motions were found to be responsible for enhanced air–water mixing on the pipe centerline. The transverse nonuniformity of the bubbly flow structure and the impact of air vent dimension are to be characterized in future studies. [ABSTRACT FROM AUTHOR]

With global cooling demand increasing, there is a need for refrigeration cycles that use low global warming potential (GWP) refrigerants. Researchers have flirted with the idea of using the Brayton cycle for refrigeration over the years, but it has yet to prove competitive in performance or cost when compared to the widely used vapor compression cycle. The recent development of an electrochemical Brayton refrigeration cycle has renewed interest in the thermodynamics of Brayton refrigeration. This work provides a parametric study of the COP of a Brayton cycle air conditioner (either mechanical or electrochemical in nature) as a function of the characteristics of the cycle components (thermal conductances and isentropic efficiencies). When the isentropic efficiencies of the adiabatic components (i.e., the compressor and turbine in the mechanical Brayton cycle) are 90 %, the cycle COP is limited to a value of ∼1. Furthermore, a thermodynamic comparison to the vapor compression cycle reveals that the Brayton refrigeration cycle generates ∼8 × more entropy, and that the thermodynamic favorability of the vapor compression cycle is due to the presence of phase change. [ABSTRACT FROM AUTHOR]

Most enterprise workshop operators frequently adjust the start/stop time of air conditioning systems based on indoor and outdoor temperatures and humidity to accommodate changing demand and weather conditions. However, relying on personal subjective experience for these adjustments often leads to operational delays or energy waste due to the lack of precision in determining optimal timing. Predicting air conditioning system start and stop times is crucial for energy consumption and savings in HVAC systems. Traditional data-driven methods have been insufficient in this regard, as they mainly focus on feature mapping and overlook the dynamic coupling relationships of process variables, resulting in subpar predictions. In response to this challenge, the paper introduces a novel approach known as the Periodicity and Long-Term Convolutional Neural Network (PLCNN). This method converts one-dimensional regression prediction data into two-dimensional data containing time series features to capture the dynamic coupling characteristics of the air conditioning system while maintaining the independent variation relationships of features. Experimental results using real factory floor data have demonstrated the superior performance of the PLCNN method. Specifically, this method achieved a 14.96% lower error rate compared to the traditional method and an 8.18% improvement compared to the deep learning method. Moreover, the implementation of the PLCNN method in the optimal control of air conditioning systems led to a significant 19.43% reduction in total monthly energy consumption. In conclusion, the proposed method offers a promising alternative to traditional approaches to forecasting and provides a solution to the common challenges encountered in traditional prediction tasks. • Capture the dynamic coupling characteristics of air-conditioning systems. • Analyzing data for periodicity and long-term patterns using various methods. • Improved integration of periodicity and long-term attributes through mutual learning. • Achieved an 11.57% lower MSE compared to different methods. [ABSTRACT FROM AUTHOR]

• An accelerated experimental method for quickly realizing the water fouling process was designed. • Water fouling process experiences the initiation, growth and stabilization stages in sequence. • 5 mm tubes are more prone to form water fouling compared with 7 mm tubes. • Screwed tubes are benefit to destroy the integrality of fouling layer compared with smooth tubes. • Fouling mass in the 5 mm smooth tube is larger than that in other types of tubes. Application of copper tubes with the diameter of 5 mm instead of 7 mm in chillers of central air conditioning systems is the development tendency due to the requirement of copper material saving. However, the heat transfer deterioration by water fouling precipitated in 5 mm tubes may be more serious than that in 7 mm tubes. The purpose of this paper is to comparatively investigate the water fouling characteristics on both 5 mm and 7 mm tubes. An accelerated experimental method of water fouling process was designed to quickly evaluate the fouling degree. Four tube types are tested, i.e. a 7 mm smooth tube, a 7 mm screwed tube, a 5 mm smooth tube and a 5 mm screwed tube, and these tubes are fabricated as flexible coiled tubes with total length of 200 cm. The results show that the water fouling process experiences the initiation, growth and stabilization stages in sequence, and the crystal form of fouling is in the vaterite, aragonite and schistosity patterns respectively. The fouling masses in 5 mm smooth tube and 5 mm screwed tube are respectively 42.1% and 16.9% larger than those in 7 mm smooth tube and 7 mm screwed tube, meaning that 5 mm tubes are more prone to form water fouling compared with 7 mm tubes; while the averaged fouling mass in screwed tubes is 2.8% lower than that in smooth tubes since screwed tubes are benefit to destroy the integrality of fouling layer and enhance the removal of deposited particulates. [ABSTRACT FROM AUTHOR]

To solve the problem of thermal discomfort caused by the lack of cooling facilities on the Ferris wheel and to investigate the effect of the coupling effect of thermoelectric modules on the thermoelectric cooling (TEC) system, this paper proposes a two-module thermoelectric cooling and air-conditioning system that can be applied to the Ferris wheel. Firstly, the experimental platform was established to test the performance parameters of the TEC system and reveal the influence of the thermoelectric module (TEM) coupling effect on the system performance. Then, the thermal environment inside the Ferris wheel was simulated using the CFD method and human thermal comfort was evaluated. The results show that when the voltage of TEM1 and TEM2 is 10 V and 6 V respectively, the thermoelectric cooling and air-conditioning system has the best working performance, and the coefficient of performance (COP) is 0.43. And the human thermal comfort deviation A EQT is 0.29, which is in a comfortable state under the action of the air-conditioning system. [ABSTRACT FROM AUTHOR]

• Proposed MTF-CNN-MSA innovative fault detection algorithm. • Conducting VRF high-precision refrigerant charging experiments. • Selection of parameters sensitive to refrigerant charging in VRF systems. • Comparison of MTF-CNN-MSA algorithm with basic machine learning algorithms. Refrigerant charging discrepancies constitute the predominant malfunctions in air conditioning systems. Achieving the optimal charging level is crucial for system performance, underscoring the importance of precise refrigerant level prediction. This study introduces an algorithm designed for the quantitative detection of refrigerant charging errors by integrating the Markov Transition Field (MTF), Convolutional Neural Networks (CNN), and Multi-head Self-Attention (MSA) mechanisms. A high-precision enthalpy difference chamber was employed to establish a Variable Refrigerant Flow (VRF) refrigerant charging test bench. This setup facilitated the analysis of system parameter sensitivity to charging faults and aided in the creation of a training dataset for the algorithm. Comparative analysis was conducted against Support Vector Machines (SVM), Random Forests (RF), CNN with Self-Attention (AT), and MTF-CNN-MSA. The findings reveal that our method adeptly captures temporal dependencies and dynamic shifts in time series as visual representations, offering novel insights for discerning fault patterns within such data. Notably, the maximum pressure variations at high-pressure and low-pressure points were 0.25 MPa and 0.07 MPa, respectively, with temperature shifts of 12 °C and 3.5 °C at the high and low-temperature points. The high-pressure and high-temperature points are particularly sensitive to changes in refrigerant charging, and parameters from these sections were utilized to construct the dataset. The CNN-MSA algorithm demonstrates consistent performance across various fault types, effectively delineating fault characteristics. The accuracies achieved by SVM, RF, CNN-AT, and MTF-CNN-MSA were 84.38 %, 73.75 %, 88.13 %, and 93.75 %, respectively. In comparison, the CNN-MSA algorithm was able to more accurately detect refrigerant charge faults at different levels. [ABSTRACT FROM AUTHOR]

• Small pressure ratio scrolls compressors often face severe under-compression. • Profile correction reduces under-compression in scroll compressors. • Modifying discharge port shape improves flow field distribution. • Adjusted discharge port shape boosts mass flow rate. • Profile changes enhance compressor performance and efficiency. The scroll compressor is an essential component in air conditioning and heat pump systems. This study examined an electric scroll compressor using R22 refrigerant, focusing on how modifications in the scroll head profile and discharge structure affect its performance. Initially, a semi-empirical model based on mathematical formulas was developed to predict the performance improvements of the updated scroll compressor. Three-dimensional simulation software was then used to illustrate changes in the internal flow dynamics before and after enhancements. The predictions were validated through experimental testing. Both the semi-empirical model and the three-dimensional unsteady numerical calculation model analyzed the effects of modifications to the tooth head profile and discharge port shape on compressor performance. The adoption of a PMP profile correction delayed the compressor discharge process, shifting the starting discharge angle from 315°to 344°, thereby reducing under-compression occurrences during operation and increasing volumetric efficiency by 1.31%. Additionally, mathematical formulas correlating temperature with compressor performance were developed from fitting data, predicting compressor behavior under various conditions. Moreover, replacing a circular discharge port with a waist-shaped port reduced power consumption by 0.59 kW, resulting in a more uniform temperature distribution and enhanced mass flow rate during compressor operation. [ABSTRACT FROM AUTHOR]

This paper reports on designing an automated two-dimensional duct of Heating, Ventilation, Air Conditioning and Refrigeration (HVACR) using computer programming. The designed system uses an algorithmic approach attempting to accelerate the design process, decrease the human error of the designers and make the process of designing HVACR systems more efficient. It applies a system of interacting algorithms to solve duct sizing, routing and layout optimisation tasks. This facilitates both the saving of time and the increment of accuracy and consistency in the final design. By applying advanced computational techniques, it could analyse complex geometries of buildings and easily produce optimised designs for ducts. This research contributes to the field of HVACR engineering by providing a practical solution for automating a critical design phase. The automation system may be configured to work with existing Computer Aided Design (CAD) software, allowing for close collaboration between designers and engineers. Major Findings: A computer program using Hyper Text Markup Language (HTML), Cascading Style Sheets (CSS) and JAVA allows for quick and accurate determination of duct size by applying standard empirical formulas that relate height, width, and diameter. The programmer can effortlessly adjust the design by simply modifying the input data and tailoring the duct specifications to meet specific requirements. [ABSTRACT FROM AUTHOR]

The aim of this work was to analyze the influence of thermal conditions and the presence of biomass in the chamber on the composting process. The work analyzed the process of the aerobic decomposition of grass, the inoculating fraction and the structure-forming fraction. The analysis covered the batch composting process using veterinary biomass in the treatment chamber. Observations of the process included the following: determining the rate of mineralization, process temperatures, pH, process gas concentrations, chemical composition, physical properties of the compost, and the maturity of the compost. In all analyzed samples, the composting process works correctly in terms of thermal parameters; the obtained fresh compost, after the thermophilic phase has ended, requires action be taken with reference to the values of the seed generation index and the respiration activity (AT4) parameter. After the thermophilic phase, after 60 days of composting, it was noted that for P1 (Probe 1) and P2 (Probe 2) mixtures, the seed germination level decreased below 10%. The AT4 parameter for the P1 and P2 compost samples was between 29.8 and 26.2 mg O2∙g−1. The improvement of the germination level to values in the 30% to 40% range for the maturing compost samples was caused by the thermal conversion of biomass with the regulation of air and water conditions. The phytotoxicity of the compost was overcome, while an improvement in the value of the AT4 index was achieved. [ABSTRACT FROM AUTHOR]

The necessity of using two-stage (multicyclone–partition) inlet air filters for engines of motor vehicles operated in dusty air conditions is demonstrated. Due to the lack of information in the literature on the description of the air filtration process in the two-stage system (multicyclone–partition), its experimental tests were performed. Due to the high cost of testing the original two-stage air filter, the original test methodology of testing a single cyclone and a paper filter with an appropriately sized surface was used. When testing the assembly (cyclone–paper filter), conditions similar to the actual operating conditions of a two-stage air filter were used, including the filtration speed in the paper filter, the dust concentration in the inlet air, and the cyclone inlet speed. The characteristics of various filter baffles with appropriately sized surface area operating in three filter assemblies, the "cyclone–test filter", and without a cyclone were determined depending on the mass of dust supplied to the assembly or directly to the filter. Experimental tests showed the existence of an initial (short) filtration period, which was characterized by low values of filtration efficiency well below the required level of 99.9%. This phenomenon occurred regardless of whether the paper filter was operated directly after the cyclone or without the cyclone. However, with the mass of dust delivered to the filter, the efficiency and precision increase and in a short time achieve the required values, which are maintained for the rest of the filter's operation. The air behind the paper filter contained dust grains of 10–25 µm with the required 2–5 µm. The increase in the pressure drop was lower for the paper filter operating in an assembly (cyclone–paper filter). Therefore, the operating time of the unit (cyclone–paper filter) to reach the permissible flow resistance value was four times longer than that of the paper filter, as could be demonstrated. [ABSTRACT FROM AUTHOR]

In this work, we prepared lead-free Cs3Bi2I9−xBrx (x = 0, 1, 2, 3, 6, and 9) thin films using a green anti-solvent method under air conditions and used them to fabricate memristors with an Al/Cs3Bi2I9−xBrx/ITO structure. These memristors exhibited non-volatile and bipolar resistance switching behavior without electroforming. Notably, the bandgap of the Cs3Bi2I9−xBrx (x = 0, 1, 2, 3, 6, 9) series films was regulated by bromine doping. The switching ratio of devices changed with the films' band gap and increased from 102 to 103. The resistance state of the Al/Cs3Bi2I9−xBrx/ITO devices was maintained even after 150 switching cycles and 104 seconds of reading. Moreover, the Al/Cs3Bi2Br9/ITO memristor showed excellent stability in the air after 100 days. This study offers beneficial insights into designing perovskite materials and regulating the performance of perovskite memristors. [ABSTRACT FROM AUTHOR]

Experiments have been performed in air and cooling-assisted condition with three tool pin profiles i.e. square, triangular and threaded cylinder. In this study, an effort has been made to comprehend how the mechanical characteristics, micro-hardness, and microstructure of friction stir welded AA6063-T6 joints are affected by in-process cooling, tool profiles, tool dimensions, and process parameters. For friction stir welding with cooling assistance, process parameters were optimised. For higher tensile and impact strength, a square tool profile with a shoulder to pin diameter ratio of 3:1 is found to be the most effective. The most important welding parameter was found to be rotations per minute (rpm). Microstructural analysis reveals finer grain size and a significant increase in microhardness in the weld nugget zone with cooling assisted FSW. [ABSTRACT FROM AUTHOR]

The thermodynamic parameter pressure is ideal for producing novel ultraincompressible and superhard materials as it promotes the formation of polymeric frameworks and higher atomic coordination. In this regard, carbon and nitrogen are particularly attractive elements as they can produce extended arrangements of strong covalent bonds. In this study, a previously unobserved C3N4 polymorph, denoted as oP28‐C3N4 (Pnnm, #58), is synthesized at pressures between 73 and 104 GPa in laser‐heated diamond anvil cells and found recoverable to ambient conditions and stable in air. The crystal structure of oP28‐C3N4, comprised of corner‐sharing CN4 tetrahedra, is solved and refined using synchrotron single‐crystal X‐ray diffraction. With a bulk modulus of 334(3) GPa deduced from experimental data, the compound is highly incompressible. Based on macroscopic and microscopic calculations, its hardness may achieve 47.5 or 79.7 GPa, respectively, making it a superhard material. Incompressibility of CN4 tetrahedra in all experimentally observed C3N4 polymorphs is found to be greater than that of the CC4 and BN4 tetrahedra forming the structures of diamond and cubic boron nitride. Density functional theory calculations provide further insight into the electronic, vibrational, and mechanical properties of oP28‐C3N4, as well as their stability relative to other C─N phases. [ABSTRACT FROM AUTHOR]

After systematic realization of decarboxylative functionalization of carboxylic acids under heating conditions in our group, we herein reported an electrochemical method for Ni‐catalyzed decarboxylative oxygenation of arylacetic acids under open air conditions. The protocol provided corresponding carbonyls including aldehydes and ketones in moderate to satisfactory yields with good functional group tolerance, furthermore, the practicability and advantage of the method was highlighted through Ni‐catalyzed oxidative decarboxylation of carboxylic acid‐containing drugs and preformation of scalable transformation. Mechanistic studies demonstrated that the possible involvement of free radical intermediate in the conversion. [ABSTRACT FROM AUTHOR]

To address the multifaceted aspects of indoor environmental sciences, this review paper critically investigates the optimization of thermal comfort and the development of heat-resilient indoor environments. Drawing on knowledge from a wide range of disciplines, such as chemistry, microbiology, public health, psychology, epidemiology, engineering, and toxicology, among others, it provides an extensive overview of recent study findings. The paper examines solutions targeted at reducing the negative impacts of heat stress while improving thermal comfort levels indoors, highlighting the complex link between indoor environment, human health, and comfort. Using both theoretical frameworks and actual data, the study assesses a variety of cutting-edge methods, such as behavioral interventions, heating, ventilation, and air conditioning (HVAC) systems, passive design strategies, and adaptable building materials. The statement underscores the importance of interdisciplinary cooperation in tackling the intricate problems related to interior thermal comfort and resistance to heat waves. The review attempts to offer practical insights for practitioners and researchers looking to optimize interior settings for human health and well-being by looking at the synergistic impacts of several treatments. Additionally, the research emphasizes how crucial it is to consider the larger context of climate change and its effects on interior spaces. To improve our understanding of thermal comfort optimization and heat-resilient design techniques, it suggests new research directions and knowledge gaps and advocates for ongoing interdisciplinary inquiry. In the end, the review adds to the continuing conversation about designing livable, sustainable, and healthful interior spaces in the face of changing weather patterns. [ABSTRACT FROM AUTHOR]

Airborne viruses are ubiquitous and play critical roles in maintaining ecosystem balance, however, they remain unexplored. Here, it is aimed to demonstrate that highly diverse airborne viromes carry out specific metabolic functions and use different transmission modes under different air quality conditions. A total of 263.5‐Gb data are collected from 13 air samples for viral metagenomic analysis. After assembly and curation, a total of 12 484 viral contigs (1.5–184.2 kb) are assigned to 221 genus‐level clades belonging to 47 families, 19 orders, and 15 classes. The composition of viral communities is influenced by weather conditions, with the main biomarker being Caudoviricetes. The most dominant viruses in these air samples belong to the dsDNA Caudoviricetes (54.0%) and ssDNA Repensiviricetes (31.2%) classes. Twelve novel candidate viruses are identified at the order/family/genus levels by alignment of complete genomes and core genes. Notably, Caudoviricetes are highly prevalent in cloudy and smoggy air, whereas Repensiviricetes are highly dominant in sunny and rainy air. Diverse auxiliary metabolic genes of airborne viruses are mainly involved in deoxynucleotide synthesis, implying their unique roles in atmosphere ecosystem. These findings deepen the understanding of the meteorological impacts on viral composition, transmission mode, and ecological roles in the air that we breathe. [ABSTRACT FROM AUTHOR]

Fischer-Tropsch synthesis represents a key endeavor aimed at converting nonpetroleum carbon resources into clean fuels and valuable chemicals. However, the current state-of-the-art industrial FTS employing Fe-based catalysts is still challenged by the low carbon efficiency (<50%), mainly attributed to the prominent formation of CO2 and CH4 resulting from the nonregulated side water gas shift reaction. Herein, we describe a shielding strategy involving the encapsulation of the active Hägg carbide (χ-Fe5C2) by a graphene layer, exhibiting excellent resilience under reaction conditions and exposure to air, thereby eliminating the need for reduction or activation before the Fischer-Tropsch synthesis reaction. The graphene layer helps to stabilize the Hägg carbide active phase, and more importantly, greatly suppresses the side water gas shift reaction. Theoretical calculations suggest that graphene shielding inhibits the water gas shift reaction by reducing the absorption strength of OHx species. Remarkably, the optimum χ-Fe5C2@Graphene catalyst demonstrates a minimized CO2 and CH4 formation of only 4.6% and 5.9%, resulting in a high carbon efficiency (ca. 90%) for value-added products. These results are expected to inspire unique designs of Fe-based nanocomposite for highly efficient FTS with regulated carbon transfer pathways. [ABSTRACT FROM AUTHOR]

AbstractApples (variety Idared) were vertically cut into cylinders, 2.0 cm in diameter and 2.0 cm in height (five pieces from one apple). The samples were first dried using different drying methods and their adsorption isotherms were compared. In addition, the samples were subjected to osmotic dehydration (OD) under different conditions (sucrose concentration, 34°–63oB; temperature, 34°–66 °C and different times) followed by air drying (AD). The adsorption isotherms of these samples (OD-AD) were also evaluated. All the adsorption isotherms were evaluated at 20 °C, using the static-gravimetric method. Adsorption isotherms data were fitted to the GAB model and the isotherms were found to be affected by the drying method as well as the OD conditions. Changes in sorption curves of OD-AD apple cylinders as induced by OD variables were studied. Adsorption isotherms of OD-AD apples were generally shifted down with respect to control samples (AD, FD, and Oven) and with increasing solute concentration. The monolayer moisture content (Mm) of the OD-AD products was comparatively lower. Adsorption isotherm of OD-AD samples followed Type II isotherms unlike the conventionally dried samples. [ABSTRACT FROM AUTHOR]

We report a novel, metal‐free procedure for the direct aminophosphonation of imidazo[1,2‐a]pyridines in green solvents under open air conditions. This method is characterized by its mild and sustainable conditions, ease of operation, scalability, and excellent functional group compatibility. The synthesized compounds exhibit promising photophysical properties, including significant Stokes shifts and quantum yields, making them potential candidates for innovative fluorescent probes. [ABSTRACT FROM AUTHOR]

We report a novel, metal‐free procedure for the direct aminophosphonation of imidazo[1,2‐a]pyridines in green solvents under open air conditions. This method is characterized by its mild and sustainable conditions, ease of operation, scalability, and excellent functional group compatibility. The synthesized compounds exhibit promising photophysical properties, including significant Stokes shifts and quantum yields, making them potential candidates for innovative fluorescent probes. [ABSTRACT FROM AUTHOR]

One possible explanation for the lack of pro‐environmental behavior among the public is that the benefits of combating climate change are long‐term and distant. Temporal discounting is a pervasive tendency to prefer small immediate gains to large delayed benefits, which may lead to a lack of motivation to engage in pro‐environmental behavior. However, exposure to nature can reduce this tendency and by extension may promote pro‐environmental behavior. Two behavioral experiments were conducted to investigate whether exposure to natural (vs. urban) scenes would induce lower discounting and increase the tendency toward pro‐environmental behavior. We demonstrated that exposure to natural (vs. urban) scenes was associated with a lower level of discounting and a greater tendency toward pro‐environmental behavior, including energy‐saving use of air conditioning (Experiment 1), willingness to participate in beach cleaning (Experiment 2), and choosing meals with less environmental impact (Experiment 2). Mediation analysis indicated that the discounting tendency mediated the relationship between exposure to natural scenes and pro‐environmental behavior. This study provides the first experimental evidence that temporal discounting accounts for the association between exposure to natural (vs. urban) scenes and the tendency toward pro‐environmental behavior. Our findings support the development of a novel strategy for promoting pro‐environmental behavior. [ABSTRACT FROM AUTHOR]

An oil-injection CO2 scroll compressor prototype and relative simulation model are developed for automotive Air Conditioning. The effects of oil to refrigerant mass ratio on the compressor performance are studied theoretically and experimentally. The results show that oil-injection is an effective way to improve the volumetric and indicated efficiencies, and reduce discharge temperature. The optimal oil-injection quantity varies at different conditions, and it decreases from 7.9% to 6.3% at fixed discharge pressure 10MPa when the suction pressure increases from 4.5MPa to 5MPa. Similar linear relationships are found and the different slopes of the line are exhibited at fixed suction and discharge pressure separately. Numerical results show that oil-injection has little influence on pressure in working chamber during suction and discharge process, but it can slow up the rising of pressure in compression process and reduce the salient of pressure at the end of compression process. [ABSTRACT FROM AUTHOR]

ABSTRACT The main purpose of this paper was to identify significant changes in air moisture conditions in Poland, which accompany climate warming. Meteorological data used in the research included the relative humidity (RH) values from 48 stations obtained from the Institute of Meteorology and Water Management—National Research Institute from 1966 to 2020. The monthly mean, standard deviation (SD) and coefficient of variation of RH from 12 PM for all months (with particular reference to the middle months of seasons—January, April, July and October) were used. Additionally, the dry weather (RH < 30%) frequency in the warm half of the year was observed. Long‐term changes were found by comparing relative humidity values in three 15‐year subperiods (1966–1980, 1986–2000 and 2006–2020) and the statistical significance was estimated using the Mann‐Kendall test. The most considerable long‐term changes were noticed in April and July, especially in the last 15‐year subperiod. The statistical significance was higher, mostly in warmer months. The SD was also higher in April and July than in January and October. Hence the humidity conditions in the warmer half of the year fluctuated more and more widely. A significant decrease in the RH mean values and an increase in SDs in spring and summer impact the increasing frequency of dry weather. Relations between meteorological characteristics suggest the warming climate contributes to drying the near‐surface atmosphere but also impacts intensive precipitation events or snow cover parameters. The decreasing trend of long‐term relative humidity may negatively impact the environment, human health and well‐being and cause serious economic losses. [ABSTRACT FROM AUTHOR]

Various isomers have been developed to regulate the morphology and reduce defects in state‐of‐the‐art perovskite solar cells (PSCs). To insight the structure‐function‐effect correlations for the isomerization of thiourea derivatives on the performance of the PSCs, we developed two thiourea derivatives [(3,5‐dichlorophenyl)amino]thiourea (AT) and N‐(3,5‐dichlorophenyl)hydrazinecarbothioamide (HB). Supported by experimental and calculated results, it was found that AT can bind with undercoordinated Pb2+ defect through synergistic interaction between N1 and C=S group with a defect formation energy of 1.818 eV, which is much higher than that from the synergistic interaction between two −NH− groups in HB and perovskite (1.015 eV). Moreover, the stronger interaction between AT and Pb2+ regulates the crystallization process of perovskite film to obtain a high‐quality perovskite film with high crystallinity, large grain size, and low defect density. Consequently, the AT‐treated FACsPbI3 device engenders an efficiency of 25.71 % (certified as 24.66 %), which is greatly higher than control (23.74 %) and HB‐treated FACsPbI3 devices (25.05 %). The resultant device exhibits a remarkable stability for maintaining 91.0 % and 95.2 % of its initial efficiency after aging 2000 h in air condition or tracking at maximum power point for 1000 h, respectively. [ABSTRACT FROM AUTHOR]

Various isomers have been developed to regulate the morphology and reduce defects in state‐of‐the‐art perovskite solar cells (PSCs). To insight the structure‐function‐effect correlations for the isomerization of thiourea derivatives on the performance of the PSCs, we developed two thiourea derivatives [(3,5‐dichlorophenyl)amino]thiourea (AT) and N‐(3,5‐dichlorophenyl)hydrazinecarbothioamide (HB). Supported by experimental and calculated results, it was found that AT can bind with undercoordinated Pb2+ defect through synergistic interaction between N1 and C=S group with a defect formation energy of 1.818 eV, which is much higher than that from the synergistic interaction between two −NH− groups in HB and perovskite (1.015 eV). Moreover, the stronger interaction between AT and Pb2+ regulates the crystallization process of perovskite film to obtain a high‐quality perovskite film with high crystallinity, large grain size, and low defect density. Consequently, the AT‐treated FACsPbI3 device engenders an efficiency of 25.71 % (certified as 24.66 %), which is greatly higher than control (23.74 %) and HB‐treated FACsPbI3 devices (25.05 %). The resultant device exhibits a remarkable stability for maintaining 91.0 % and 95.2 % of its initial efficiency after aging 2000 h in air condition or tracking at maximum power point for 1000 h, respectively. [ABSTRACT FROM AUTHOR]

A considerable amount of water condensate produced through the cooling coils of air conditioning systems is usually directed to municipal sewage systems and wasted along with the energy it contains. This energy can instead be utilized to increase the efficiency of air conditioning systems and refrigeration systems in cold storage facilities, save energy consumption, reduce the carbon footprint, and also meet some of the water consumption needs. Since the choice of how to use condensate energy depends on its potential, i.e., the amount of collected water, this thermodynamics study estimates the amount of collected water and investigates the effects of various parameters such as ambient temperature, relative humidity (RH), coil temperature, etc., on the amount of water produced. The research results indicate that RH and air flow rate over the cooling coil have the greatest impact on the amount of water produced. [ABSTRACT FROM AUTHOR]

A research endeavor is currently underway to examine the experimental analysis and development of a fuzzy model aimed at predicting the Coefficient of Performance (COP) and Mass Flow Rate within the parameters of a refrigeration process utilizing a novel refrigerant blend with nano additive materials was used. Through the application of Fuzzy logic methodology, the inquiry has pinpointed the process parameters that exhibit the most advantageous outcomes in attaining an elevated COP, alongside diminished values for compressor discharge temperature, compressor power, and mass flow rates. The investigation delves into the potential utilization of a blend comprising R152a, R290, R600, and R600a with nano particle of Al2O3. Validation of the projected outcomes was carried out through confirmation tests, which have deemed the results to align precisely with the anticipated values. The principal objective of this empirical investigation is to evaluate the operational efficacy of a residential window air conditioning unit when contemplating the substitution of R-22 with a blend of R152a, R290, R600, and R600a with nano particle of Al2O3. [ABSTRACT FROM AUTHOR]

Over the past two decades, extensive research has elucidated the significant contributions of various nanomaterial such as metals, metal oxides, carbon nanotubes (single, double, and multi-wall), nanowires, and graphene in improving the tribological and thermal properties of AC & R systems used in both industrial and domestic settings. A recent research paper has specifically focused on the performance enhancement of AAC through the use of Nano-oxides, namely CuO, ZnO, and TiO2, employing mathematical modeling. This study investigates how dispersed Nano-oxides of CuO, ZnO, and TiO2, when added to a base of POE lubricant and HFC-R134a refrigerant, influence the performance of automobile air conditioning systems. The primary focus is on viscosity, heat transfer rate, and thermal conductivity of the working medium. The experimental results are compared with tested data, and further analysis is conducted using TK Solver 6.0 and Origin Lab software. The findings demonstrate that the incorporation of these Nano-oxides has a positive impact on thermal-physical properties (k-Thermal conductivity, ρ-viscosity, ρ-density and Cp-specific-heat) and heat transfer characteristics compared to systems without Nano-materials. Furthermore, there is a notable increase in Coefficient of Performance (COP) ranging from 23–29% with varying volume concentrations of Nano-oxides (0.5% to 2.5%) under atmospheric temperature conditions. Consequently, the combination of copper oxide, Zinc Oxide, and Titania nanoparticles with HFC-R134a as well as R1234ze (E) proves to be an effective approach for optimizing refrigerant properties and improving the performance of automobile air conditioning systems. Thus, Nano-oxides dispersion offer a promising solution for enhancing energy efficiency and reducing the reliance on conventional energy sources in thermal systems. [ABSTRACT FROM AUTHOR]

4‐Aryl‐1,4‐dihydropyridines are prevalent pharmacophores and versatile building blocks in medicinal and synthetic chemistry. Herein, we demonstrated a mechanistically distinct radical‐radical cross‐coupling approach to 4‐aryl‐1,4‐dihydropyridines, via direct C4−H arylation of 1,4‐dihydropyridines with readily available cyanoarenes. This mild protocol is initiated by the direct photoexcitation of 1,4‐dihydropyridines, eliminating the need for expensive photocatalysts and enabling operation under ambient air conditions. [ABSTRACT FROM AUTHOR]

Uneven heating of the human body in the cabin is one of the main reasons for poor thermal comfort. In this study, five small thermoelectric cooling devices were used to build the automobile localized air conditioning system to improve body temperature uniformity by the method of multi-point air supply. The cooling capacity of each thermoelectric cooling device can be changed independently so the localized air conditioning could work with a non-isothermal jet air supply method to optimize each thermoelectric cooling device outlet temperature based on thermal simulation analysis results aimed at better body heat flux balance and lower power consumption. The air temperature and skin temperature test were done to verify the simulation as well. The maximum deviation of the predicted stable air temperature was 0.82 ℃. The maximum deviation of the predicted skin temperature was 1.83 ℃. The subjective evaluation experiment of human thermal comfort was carried out, and the average overall thermal comfort vote of the volunteers was changed from 1.02 to − 0.44 after the localized air condition turning on, which showed that the temperature adjustment had a good effect on improving the heat balance and the thermal comfort of the human body. [ABSTRACT FROM AUTHOR]

Objectives: Microbial contamination of various accessory parts of the dental chair units (DCUs) is an essential source of cross infection, while the accessories of the crucial suction function are usually overlooked. In this study, we aim to find an effective disinfectant and a cost-effective method to remove bacterioplankton and bacterial biofilm deposited in the negative pressure suction pipelines to control cross infection during dental treatment. Methods: Double-chain quaternary ammonium salt disinfectant (Orotol Plus®), 3% hydrogen peroxide solution plus multi-enzyme cleaning agent and chlorine disinfectant are used to clean and disinfect the negative pressure pipelines of DCUs. Microbiological examinations, air condition detection, corrosion tests and gene sequencing are performed. Results: Little bacteria grow in the pipelines disinfected with double-chain quaternary ammonium salt disinfectants, destruction of biofilms in these pipelines appears, and multi-resistant bacteria cannot be detected. Minimal damage to metal sheets and fittings is caused by double-chain quaternary ammonium salt disinfectants. Conclusion: Double-chain quaternary ammonium salt disinfectant has excellent bactericidal ability and anti-biofilm effect, and it is less corrosive to the fittings of the pipelines. Thus, the double-chain quaternary ammonium salt disinfectant is a potential novel disinfectant for negative pressure suction pipelines of DCUs to control cross infection during dental treatment. Clinical significance: It is essential to add all these data to our dental practice to control cross infection with a broader landscape. [ABSTRACT FROM AUTHOR]