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An airflow‐induced separation method for stacked paper labels is proposed with a stream of compressed air used to jet vertically onto the side of the stacked labels and force constraints applied to the two ends of the labels. Its mechanism is revealed that the viscous force caused by airflow is the main driving force for the initial separation of labels and the vertical force is the main factor for the formation of successive separation channels. Theoretical and experimental analyses are implemented to ensure the effects of airflow velocity, label characteristics, label stress, and other factors on label separation and show that a stable separation gap can be generated with separation efficiency of more than 3600 sheets per minute and reliability of 99.99%. A complete airflow‐induced label separation device is designed, which can be integrated into the existing packaging machine, and the physical feasibility of the stack label separation method is verified by experiments. [ABSTRACT FROM AUTHOR]

This paper aims to explore machine learning techniques for post‐processing high‐resolution Numerical Weather Prediction (NWP) products for the early detection of convection. Data from the Arome Ensemble Prediction System and satellite observations from the Rapidly Developing Thunderstorm (RDT) product by Météo‐France are used to train a recurrent neural network model to predict areas of total convection and moderate convection. The learning task is formulated as a binary classification problem using a long short‐term memory (LSTM) network architecture. Results from the LSTM model are compared with an object‐based probabilistic approach to forecast convection using metrics such as a receiver operating characteristics (ROC) curve, the Brier score and reliability. Results indicate that the LSTM model performs similarly to the object‐based probabilistic benchmark when classifying moderate convection areas and shows improved skill when classifying areas of total convective. Finally, the LSTM model results are presented within an air traffic management context to showcase the potential use of machine learning models within an operational application. [ABSTRACT FROM AUTHOR]

An atmospheric pressure glow discharge in air stabilized by a magnetic field is reported. The plasma is fixed at a position when the direction of the Lorentz force and the direction of the air flow is opposite. Under such condition, a stable glow discharge can be achieved and the plasma parameters can be independently controlled by the applied voltage, the magnetic field and the air flow rate, which is not the case for the widely used gliding arc (GA) discharge. For applied voltage of 6.5 kV, air flow rate of 2 L min−1, and magnetic field of 0.11 T perpendicular to the paper pointing outward, the discharge voltage (Vdis) and discharge current (Idis) are 1.2 kV and 49.7 mA, respectively. The rotational and vibrational temperature is about 3420 K and 4550 K, respectively. The electron density is on the order of 1014 cm−3 and the reduced electric field of plasma is about 36.9 Td, which is favorable for vibrational excitation of N2 to promote the production of NOx. As the plasma is fixed at a position, all the gas has to pass the plasma region and treated by the plasma when they are flowing, which is not the case for GA discharge where only a little percentage of gas is actually treated by the plasma. The energy cost of NOx production for the plasma stabilized by magnetic field of 0.19 T pointing outward is about 2.65 MJ mol−1, which is 41% lower than the GA discharge. [ABSTRACT FROM AUTHOR]

This paper analyses the effect of the standard gravity model variables and of various multinational agreements—namely the Euro, the European Union (EU), the Schengen Agreement and other regional trade agreements (RTAs)—on the volume of air cargo flows. To compare the impacts, the data set created for this analysis contains intra‐ and extra‐European air cargo flows as well as data on air passenger and total trade flows. The results suggest that the impact of the analysed multinational agreements on air cargo flows diverges completely from their impact on total trade flows—however, the effects on air cargo flows are more similar to the effects on air passenger flows. Whereas the Euro and the Schengen Agreement affect air cargo volumes positively, EU membership and other RTAs do not significantly affect trade by air. Methodology‐wise, different dynamic structural gravity models are formulated and estimated with Poisson pseudo‐maximum likelihood (PPML). Including intranational flows and controlling for multilateral resistance, endogeneity and globalisation effects reverses the impact of some of the policy variables compared with an estimate based on a simple structural gravity model. [ABSTRACT FROM AUTHOR]

This paper investigates a CFD‐based analysis for gas–liquid and liquid–liquid Taylor flows through a circular axisymmetric microchannel with a sudden enlargement. A series of simulations are conducted by exploring the influence of different superficial velocity ratios, apparent viscosities, and channel expansion on the hydrodynamics of slug flow. A concentric junction introduces dispersed airflow into a continuous flow of water for gas–liquid flow, and the junction introduces dispersed water into a continuous flow of dodecane for liquid–liquid flow. The air‐bubble and water‐slug evolution processes, slug breakup, and slug expansion are investigated. In all cases, the lengths of air bubbles and water slugs increase with increasing superficial velocity ratio, particularly before the expansion. For gas–liquid flow, the apparent viscosity ratio causes a fluctuating interface over the uniform film region. However, the water slug length is shorter and the film region is slightly thicker in liquid–liquid compared to gas–liquid flow. The numerical analysis developed in this paper is in good agreement with the existing correlations and experimental data in the literature. [ABSTRACT FROM AUTHOR]

Air cooling is a common cooling strategy to guarantee the performance and safety of electric vehicles, in battery thermal management systems (BTMS). Based on the traditional Z‐type and U‐type, a novel F‐type air‐cooling BTMS is proposed in this paper. The computational fluid dynamics (CFD) method is used to investigate the cooling performance of F‐type BTMS, and the effectiveness of the CFD method is verified by experiments. First, the effect of the outlet's position on the cooling efficiency of the F‐type BTMS is explored. It is revealed in the results that the outlet's position plays an important role in the cooling effect. Subsequently, the angle of the distribution manifold of the F‐type model is optimized. It is shown in the results that the maximum temperature (Tmax) and the maximum temperature difference (ΔTmax) of the optimized model are reduced by 2.28 (5.22%) and 4.36 °C (89.33%), respectively, compared with the Z‐type model. Then, baffles are added to some air flow channels and the shape of the battery box top corners is changed to further optimize its heat dissipation performance. Compared with the Z‐type model, the Tmax and ΔTmax of the optimum model are decreased by 2.48 (5.66%) and 4.60 °C (94.26%), respectively. [ABSTRACT FROM AUTHOR]

The initial aim of the paper is to improve the ammonia removal efficiency from skim latex using air stripping in an agitated column. The effects of air flow rate, bubble sizes, types of impellers, and rotational speed were investigated. The results showed that ammonia decreased with the increased air flow rate and the decreased bubble size. More ammonia could be removed by the use of impellers at a low rotational speed. The axial flow impeller showed higher ammonia removal than that gained from the radial flow impeller. It could be concluded that the stripping process in an agitated column should be operated at an air flow rate under the homogeneous regime without pH and temperature adjustment. The use of axial flow impeller at a rotational speed below the turbulent flow is recommended for more ammonia removal. In addition, smaller bubbles than the working range proposed in this research should be avoided because of foaming formation of the skim latex. [ABSTRACT FROM AUTHOR]

Complex terrain near the Hong Kong International Airport (HKIA) is likely to bring about low‐level windshear and turbulence to the aircraft, which could result in aviation hazards. In the past, some isolated case studies have been presented on the complicated airflow at the airport region in Hong Kong. This paper presents a more comprehensive discussion of the terrain‐induced airflow disturbances at the HKIA, including extensive mountain wake, transient low‐level jet stream, elongated mountain wake, reverse flow and mountain wave. The performance of a super high‐resolution numerical weather prediction model in the forecasting of these weather phenomena is also discussed. The model turns out to be capable of forecasting most of the terrain‐disrupted airflow, and it may be possible to obtain an earlier indication of the occurrence of low‐level windshear for airports with complex terrain. However, some mesoscale weather phenomena, such as low‐level jet stream, may not be captured by the models, and the associated windshear events would be difficult to forecast. This paper could hopefully be a useful reference to the aviation weather forecasters in the prediction of wind and windshear at airports with similar complex terrain in other parts of the world. [ABSTRACT FROM AUTHOR]

In this paper, a novel air‐cooled supercapacitor thermal management system (STMS) based on the corner deflectors and the inclined inlet and outlet was proposed. The temperature and velocity fields were simulated and analyzed by CFD. Moreover, the heat dissipation effect of different STMSs was analyzed against each other. The results showed that the STMS proposed had a better heat dissipation effect when the inclined angle of inlet and outlet was appropriate, in which the maximum temperature (Tmax) and the maximum temperature difference (ΔTmax) of the module could be reduced by 10.3% and 34.6%. And it is shown that the structure with inclined inlet and outlet plays an important role for the heat dissipation capability of the STMS proposed. And it has experimentally proven its heat dissipation ability. Consequently, the impacts of inclined angle (α), monomer spacing (dc), and the distance between monomer and module shell (dx, dy, and dz) on the heat dissipation effect were deeply analyzed. For the STMS arranged in four rows and three columns, it had a better heat dissipation effect when inclined angle was in the range of 40° to 50°. The results showed that the structural parameters had a large influence on the Tmax and ΔTmax. Besides, it had shown that the temperature curves of the Tmax and ΔTmax had a main trend of “decreasing and then increasing” when the monomer spacing as well as the distance between monomer and module shell are taken from 1 mm to 5 mm. It implies that a small spacing (1 mm to 2 mm) will hinder the air circulation and reduce heat dissipation, and a large spacing (3 mm to 5 mm) will reduce the average flow rate of air and reduce the efficiency of heat transfer. [ABSTRACT FROM AUTHOR]

The airport line plays an important role in the airport landside traffic connection, which greatly relieves the urban road pressure. Studying the characteristics and laws of the time and space distribution of the airport line passenger flow will provide basic support for the airport line's capacity configuration, passenger flow control, and air‐track coordinated operation, and will also provide quantitative basis for the layout of urban terminal buildings. This paper proposes a method to analyse the temporal and spatial distribution characteristics of airport line passenger flow based on AFC card swiping data. By mining and extracting the travel behaviour data of subway airport line air passengers, the distribution characteristics of airport line passenger flow are analysed and visualized from two aspects of passenger travel time and space. Finally, a case study is carried out based on the actual data of Daxing airport express. The results show that: (1) the travel time of departure and return passengers is concentrated in 60–90 min; (2) The departure and arrival points of passengers are concentrated within the Fourth Ring Road, and a large number of air passenger flows are gathered and evacuated at hubs such as Beijing South Railway Station and Beijing West Railway Station. [ABSTRACT FROM AUTHOR]

This paper analyses temperature and snow patterns of winters (December–February) averaged for the territory of the Czech Republic during the 1961–2021 period and their broad environmental impacts and responses. Series of mean, maximum, minimum, absolute maximum and absolute minimum temperatures show significant increasing linear trends, while decreasing trends were detected in numbers of frost, ice and extremely cold days, duration of cold waves, snowfall days, sums of heights of new snow, days with snow depths ≥1 cm, mean and maximum snow depths. The winter severity, derived from five temperature and five snow variables and expressed by temperature/snow scores, indicates decreasing severity of winters for 1961–2021, in which temperature severity is more pronounced than that of snow. Decreasing winter severity is in line with decreasing frequency of cyclonic and directional circulation types according to objective classification, while the trend in anticyclonic types was opposite. Types with maritime airflow from the Atlantic Ocean and the Mediterranean contribute to milder and types with continental airflow from the east to colder winters. The coldest winters, 1962/1963 and 1984/1985, and the mildest winters, 2006/2007 and 2019/2020, were analysed in greater detail. Concerning of different analysed environmental impacts, they are influenced not only by severe winter weather, but also by political, socioeconomic and general environmental changes in the country. In line with decreasing winter severity were only statistically significant decreasing trends in proportions of traffic accidents connected with snow and glaze ice on the roads and volumes of damaged wood due to high weights of snow and ice deposit, expressed as salvage felling. Series of other environmental impacts (e.g., fatalities attributed to weather, impacts on the economy and society) reflect rather severity of individual winters and express high interannual variability without any representative trends. [ABSTRACT FROM AUTHOR]

When the unsaturated zone of the unconfined aquifer is covered by a low‐permeability upper layer, significant airflow will be generated in the unsaturated zone during water pumping. However, high permeability preferential flow zones (PFZs) such as fractures and macropores are frequently present in the unsaturated zone, forming the preferential fluid flow paths, which may change the original airflow pattern in the unsaturated zone during the pumping test and consequently affect the precision of obtained aquifer hydraulic parameters. The main objective of this paper is to investigate the effect of PFZs in low‐permeability upper layer on pumping‐induced airflow in the unsaturated zone by numerical simulations of transient three‐dimensional air‐water two‐phase flow and to quantify errors in the aquifer hydraulic parameters obtained during pumping test. The results demonstrate that a large amount of air flows quickly from the atmosphere into the unsaturated zone through the PFZs, and that the PFZs can draw some air from the nearby low‐permeability soils as well. The significant influx of air through PFZs also reduces the negative air pressure in the unsaturated zone and decreases the drawdown in the saturated zone at intermediate times, which are nevertheless still greater than the results obtained in the homogeneous aquifer. Estimations of the aquifer hydraulic parameters reveal that errors of these parameters obtained are smaller when the PFZs with favourable combinations of permeability, width and quantities facilitate more air to flow into the unsaturated zone. [ABSTRACT FROM AUTHOR]

Low global warming potential (GWP) refrigerants are vital to mitigating the effect of heat systems on climate change. A low GWP mixture, RGT2 (R134a/R1234yf/R161, 54%/43%/3% weight), was proposed as an alternative refrigerant for R134a in heat pump systems. This article presented the results of an experimental investigation evaluating RGT2 as a possible replacement for R134a in a closed heat pump drying (CHPD) system and studying the drying characteristics of fig slices. The experiment concluded that RGT2 has a higher coefficient of performance (COPhp) value than R134a, on average, by 1.92%, achieving lower discharge temperature and pressure ratio at different condensing temperatures (45°C–70°C). Although the heating capacity of RGT2 was slightly lower, it still met the requirements of HPD. With careful consideration of the environment, performance, and safety, RGT2 was a suitable substitute for R134a in the drying field. In addition, the drying characteristics of fig slices were significantly affected by the air temperature. The effective diffusion coefficient (Deff) and specific moisture extracted ratio (SMER) are increased by increasing temperature and air flow rate. The two‐term model was the better model to accurately predict the fig slices drying process. The highest mean Deff and SMER of CHPDS were obtained as 6.4518 × 10−10 m2/s and 39.197 g/kWh, respectively, at the highest drying air temperature. Practical Application: A mixed refrigerant (RGT2) was proposed to replace R134a, and its GWP value was about 61% lower than that of R134a. Most of the studies on substituting R134a in the literature are simulations. This paper aims to evaluate the substitutions' feasibility theoretically and experimentally. The results have been assessed to provide better information about RGT2 as a potential substitute for R134a with superior comprehensive performance. Drying kinetics has also been determined experimentally, which helped to simulate fig drying. This study will provide a reference for refrigerants replacement in heat pump drying. [ABSTRACT FROM AUTHOR]

Development of novel methods to inhibit ammonia (NH3) volatilization losses has become a strong research focus to reduce the environmental impact of agriculture and as a potential area for growth in the fertilizer industry. European Union legislation on the regulation of NH3 emission from mineral fertilizers after 2030, will only allow urea fertilizers with reduced NH3 emissions by at least 30% to remain in use. The recent increase in fertilizer prices has also created a renewed impetus to curb these losses. This paper details the results of an experiment comparing the rates of volatilization from granular urea treated with NutriSphere-N ®, untreated urea and an unfertilized control as well as placing the results in context by conducting a review of similar studies featuring NutriSphere-N ®. The study was conducted in a light and temperature-controlled growth chamber using the chamber built in air flow which collected any NH3 volatilized from a flask containing fresh soil with applied treatment and transported the NH3 to an acid trap where the volatilized NH3 was captured and exhaust air was removed. The experiment ran for 3 weeks and resulting samples were analysed colorimetrically and adjusted for differences in airflow. The temporal results show that urea dominated the flux profile but the pattern of fluxes from the two fertilizer N treatments were similar. When analysed cumulatively over the duration of the experiment, the fluxes from the NutriSphere-N ® treated urea were significantly (p = .018) (86%) lower than untreated urea and were not significantly different from the untreated control (p = .959). [ABSTRACT FROM AUTHOR]

Medicinal plants are widely used in various traditional and modern medical methods due to their therapeutic properties. Drying is a common method used to preserve the biochemical compounds of medicinal plants. Still, conventional drying methods can lead to the loss of active compounds due to exposure to high temperatures. This research aimed to design and construct an ozone generator for use in a combined dryer and evaluate the ozone, temperature, and hot air flow rate on the quality properties of mint (Mentha spicata L.). Drying experiments were conducted at varying temperatures, air flow speeds, and ozone levels. Results indicated that increasing temperature reduced total phenol and flavonoid content while increasing antioxidant capacity. Higher airflow speed positively influenced total phenol, total flavonoid content and antioxidant potency but reduced drying time. Ozone exposure increased total phenol, flavonoid content, antioxidant activity, and had minimal effect on drying time. Optimization revealed that a temperature of 52.47°C, air flow rate of 1.5 m/s, and 90.37% ozone concentration yielded favorable outcomes, including enhanced phenolic and flavonoid content, antioxidant power, and decreased energy consumption. Compared to other drying methods, the proposed ozone‐enhanced method proved superior in preserving bioactive compounds and maintaining a reasonable drying time. Overall, the research highlights the potential of ozone‐assisted drying for optimizing the quality of medicinal plants during preservation. Practical Application: The paper introduces a novel and efficient method for preserving the quality of medicinal mint. By concurrently applying ozone and infrared drying techniques, this approach aims to capitalize on their synergistic effects in maintaining the plant's beneficial compounds. Ozone acts as a natural antimicrobial agent, preserving the plant's integrity, while infrared drying expedites the process without compromising the phytochemical profile. This innovative method not only ensures microbial safety and extended shelf life but also enhances the mint's aroma, flavor, and nutrient retention. The practical application of this combined technique holds promise for pharmaceutical and herbal industries, providing a valuable approach for optimizing the drying process and preserving the medicinal attributes of Mentha spicata L. [ABSTRACT FROM AUTHOR]

This paper aims to analyze solar and microwave drying of Horehound leaves (Marrubium vulgare) from an exergetic point of view. Solar drying tests in forced convection were performed at airflow rates (150 and 300 m3/h) and air‐drying temperatures (60°C, 70°C, and 80°C), where the microwave tests were performed in microwave powers ranging from 50 to 450 kW. Four performance parameters were investigated: exergy of evaporation, exergy loss, and exergy efficiency, sustainability index, and the improvement potential rate of the drying chamber and drying process. The results show that the exergy efficiency increases with the increase of aerothermal conditions. Exegetic performances essentially depend on the drying air temperatures and the airflow rates. The exergy efficiency of the drying process is higher than that of the drying chamber. The drying characteristics of Horehound leaves treated under microwave irradiation is a crucial process to predict its moisture content design so as to optimize the drying process. The exergetic analysis presented in this manuscript shows an improvement in the sustainability index of the drying processes and the reducing losses due to the irreversibility of large‐scale production of dry plants by using solar dryer systems. The techno‐economic analysis performed on the solar dryer including the calculation of the cost of production of 1 kg of dried product shows the economic profitability of drying this kind of product using the convective solar dryer. [ABSTRACT FROM AUTHOR]

In olfactometric studies, a technique used to measure insect behavioural bias towards airborne chemicals, many of the factors that could affect the bioassay outcome other than the volatiles themselves are carefully controlled (e.g. lighting conditions, temperature, spatial position, physiological state of the insects, time of day when the bioassay is performed) but one factor, namely humidity, is overlooked frequently when studying responses to plant volatiles. Many insect species respond positively and negatively to changes in humidity and, during bioassays, differences arising from odour choices with different water vapour release rates might have confounding effects versus the original intent of the behavioural study. The present study aims to assess the effect of different substrates on the water vapour content of air in an olfactometer-like set-up. The results show that airflow humidity is affected by the odour source used in the olfactometer air flow. In addition, the response of the aphid parasitoid Aphidius colemani Viereck (Hymenoptera: Aphidiidae) is studied towards different humidities and plant material in an olfactometer. The present study suggests that humidity needs to be controlled in olfactometric studies. [ABSTRACT FROM AUTHOR]

In this paper, elastodynamic responses of the layered transversely isotropic unsaturated subgrade–pavement system subjected to the moving load are investigated. The unsaturated subgrade soil is described via a triphasic Biot‐type model introducing the effect of matric suction, immiscible flows of water and air, and transverse isotropy. The rigid pavement is modeled by the Kirchhoff plate theory, while the flexible pavement is modeled by the stratification medium theory. First, the governing equations of the unsaturated subgrade soil are obtained after algebraical manipulations. The precise integration method (PIM) is further combined with the double Fourier transform to solve the governing equations. The subgrade soil solution is utilized as the flexible coefficient to describe the plate–soil interaction, and the solution of the pavement is further acquired via the double inverse Fourier transform. Four verification examples regarding literatures and COMSOL are presented to verify the correctness of the theory. Finally, numerical examples are conducted to investigate the effect of various parameters on the dynamic behavior of the unsaturated subgrade–pavement system. [ABSTRACT FROM AUTHOR]

With the involvement of sinusoidal containers of phase change material (PCM) inside the duct, new configuration for the ventilation system has been achieved in the current paper. Mixture of TiO2 and RT25 was assumed as PCM, and the temperature of domain is fixed at 25°C at the start of the process. Owing to the radiation of the sun, air becomes warmer up to 35°C and with entering the air into the domain with Re = 6000, the melting process starts. The cold air at the outlet section can be utilized for ventilating the room. Homogeneous model for NEPCM and K‐ɛ approach for turbulent air flow has been incorporated. ANSYS FLUENT was applied for simulating this unsteady mechanism, and verification of the model was done according to previous experimental work. To control the air gap among tanks, the factor "b" was utilized and the influence of the fraction of titanium oxide (ϕ) was analyzed in results. As nano‐sized material has been added, more heat can be received to RT25 and the completed process can be reached in lower time. With considering the highest "b," as nano‐sized material, the required time reduces from 20,672 to 19705 s. When ϕ = 0, growth of b leads to a reduction of time of about 42.57%. [ABSTRACT FROM AUTHOR]

Shotcrete 3D Printing is a 3D printing process in which the concrete is applied layer by layer using a wet mix process. In the print process, a large number of different process as well as material parameters can be varied, which also influence the hardened concrete properties. A systematic understanding of the interaction between material and process is required to define limits for material and process control variables with respect to the resulting component quality. Therefore, in this paper we present results on the effect of concrete volume flow (0.4; 0.8 m3/h), air volume flow (30; 40; 50 m3/h) and accelerator dosage (0; 3; 6 % by weight of cement) on global density, local density distribution as well as flexural strength. The results show that the combination of an increasing concrete volume flow, a decreasing air volume flow and an increasing accelerator dosage lead to a decrease in global density and flexural strength. A high correlation between the global density and flexural strength can be demonstrated despite the layer‐by‐layer fabrication. In addition, an inhomogeneous density distribution over the cross section is shown. Finally, the underlying mechanisms are discussed regarding the influence of the material and process parameters. [ABSTRACT FROM AUTHOR]

The performance of inherent orifice‐restricted aerostatic bearings (IORABs) is directly determined by the coupling of air flow in the orifice and clearance. This paper presents a novel full‐region model to analyse the performance of IORABs. The air flowing in the orifice is treated to be adiabatic. The air flow in the pressure depression region of the clearance, which is the key factor influencing the bearing performance, including inertial and viscous terms, is modelled. The Reynolds equation is used to simulate the air flow in the laminar flow region of the clearance. By using this model, the pressure distribution, including the pressure depression characteristics, could be accurately predicted and achieved substantial agreement with the experimental results. The predicted load capacity is accorded well with the published experimental data without relying on the discharge coefficients. The airflow characteristics in the orifice are crucial in determining the bearing performance and directly influenced by the orifice inner surface shape (OISS). Therefore, the pressure distribution and the static characteristics of the bearings with coupling different OISS are also systematically analysed by using this model. Narrowing and widening OISS influence the pressure depression region and the pressure value of the turning point to directly influence the static characteristics of the bearings. The full‐region model and the results are significantly for guiding the precisely calculating and designing the IORABs. [ABSTRACT FROM AUTHOR]

Extremely persistent heavy rainfall (EPHR) events frequently occur in southern China. The mechanisms underlying their generation and development are not well understood, and this leads to difficulties in accurately forecasting these events. In this paper, hourly precipitation grid data and ERA‐5 reanalysis data are used to examine the relationships between precipitation, ageostrophic winds, and low‐level jets (LLJ). The results suggest that ageostrophic winds in the boundary layer mainly exhibit confrontational and asymptotic convergence, with the former being accompanied by double LLJ, which transport more vapor and provide favorable uplift conditions, thus producing stronger precipitation and wider rainbands. The different cooperated relationships between LLJ and ageostrophic winds play an important role in the development of EPHR events, and greater account needs to be taken of these relationships when forecasting. Plain Language Summary: Coastal extremely persistent heavy rainfall (EPHR), long‐duration heavy rainfall in local coastal area, occurs frequently in Southern China, and this kind of rainfall is usually accompanied by southwesterly in the lower atmosphere, which we call as the southwest low‐level jet. Generally, the occurrence and development of rainfall is accompanied by the convergence of the lower air flow. Since the divergence of the geostrophic wind component of the wind field is zero, the convergence situation is characterized by the ageostrophic wind component, which doesn't satisfy the geostrophic balance. In this type of coastal EPHR accompanied by the Southwest Jet, the ageostrophic wind is mainly manifested in two different convergence situations. One is that the ageostrophic wind presents several opposite branches of directions presenting a confrontational pattern around the rainfall area, and the other is an asymptotic convergence in which two similar wind directions, such as northeasterly and southeasterly, gradually converge to the rain area. The former has stronger lower‐level uplift, greater precipitation and wider rain bands, while the latter is relatively weak. This is an interesting phenomenon, of which the specific mechanisms need to be further studied. Key Points: About 74% of extremely persistent heavy rainfall cases along the coast of southern China are accompanied by southwest jets in the marine boundary layerAgeostrophic winds mainly exhibit confrontational and asymptotic convergence, and the former is accompanied by double low‐level jetsCases of ageostrophic winds with confrontational convergence have stronger precipitation and wider rainband [ABSTRACT FROM AUTHOR]

Summary: Nowadays, clinical examination process requires continuous data for evaluating the patient health. Due to the importance of medical data, wireless sensor network is used to collect the large volume of patient health information. The collected data includes the patient body temperature, blood pressure, heart rate, air flow, glucose level, which helps to provide the initial treatment and avoid serious situation. The gathered information must be transmitted to the health care center without affecting the quality of data because its quality issue leads to create the packet drop, transmission throughput, maximum energy consumption, and delay. Hence, this paper develop the optimized routing protocol called bacterial bee swarm–based hybrid lifetime maximization large‐scale mobile ad hoc routing protocol for performing data transmission process. The developed system examines the quality of data while improving the network lifetime in large area of mobile ad hoc network. The optimal path and data quality are continuously monitored and effective path and node are selected based on the bacterial bee swarm functions. Then, the efficiency of the system is evaluated with the help of experimental results in terms of energy consumption, packet delivery ratio, end‐to‐end delay, and QoS metric related constraints. [ABSTRACT FROM AUTHOR]

In this paper, we consider a vibration suppression problem for a pneumatic isolation table with on–off valves using the feedforward control input profile. In this system, it is possible to enhance the vibration suppression performance by adjusting the flow rate of air into and from air springs. However, there is a significant problem that a steady‐state deviation, namely an offset, for displacement of the table occurs. Therefore, we propose an efficient search method of the optimal feedforward control input profile, which provides high vibration suppression performance without a steady‐state deviation. A key idea is to update the control input profile to belong to a space where velocity of the table does not change. [ABSTRACT FROM AUTHOR]

This paper investigates turbulent exchange processes in a droplet‐laden air flow over a waved water surface by performing direct numerical simulation (DNS). Turbulent Couette flow is considered in DNS as a model of a constant‐flux layer in the marine atmospheric surface layer. Two‐dimensional stationary waves at the water surface are prescribed and assumed to be unaffected by the airflow and/or droplets. Evaporating droplets of different sizes are injected into the air in the vicinity of wave crests with initial velocities and temperatures of water, and thus mimicking spume sea‐spray droplets. Evolution equations of the airflow velocity, temperature, and humidity are solved in a Eulerian framework simultaneously with the equations of individual droplets coordinates and velocities, temperatures, and masses tracked in a Lagrangian framework. The momentum (Qm) and sensible (QS) and latent (QL) heat fluxes from the droplets to air are evaluated both as phase‐averaged Eulerian fields and as fluxes integrated over time along Lagrangian droplets trajectories. The results show that droplets extract momentum from the surrounding air (Qm < 0), and QL > 0 and increases with droplet diameter, d, whereas QS < 0, reaches maximum for droplets with diameters of the order of 200 μm, and saturates for larger droplets. The resulting enthalpy flux QS + QL > 0 vanishes for droplets with diameters d < 100 μm, and increases with d for larger droplets. DNS results also show that droplets reduce mean air velocity and temperature and increase relative humidity as compared to the droplet‐free flow. Plain Language Summary: This study is concerned with numerical simulation of momentum, heat, and moisture exchange processes occuring in the marine atmospheric boundary layer. In particular, the influence of sea‐spray drops on these processes is investigated. It is shown that drops reduce the mean air velocity and temperature, and increase relative humidity as compared to droplet‐free flow. Key Points: This paper investigates exchange processes in a droplet‐laden air flow over a waved water surface by performing numerical simulationThe impact of drops on the flow including both momentum and latent and sensible heat exchange between drops and air is taken into accountDNS results show that drops reduce mean air velocity and temperature and increase relative humidity as compared to the droplet‐free flow [ABSTRACT FROM AUTHOR]

Drying of foods is a processing step, which has a variety of outcomes from improving shelf life and product stability, to reducing weight, or to achieving a targeted product eating quality. Drying is key step in the manufacturing of some dried meat products, such as jerky. It is also a major event that occurs when beef is dry‐aged, where beef is exposed to air under defined conditions for an extended aging period. Although the conditions typically used to produce dried meat products are significantly different from those that prevail during dry‐aging, both involve a gradual removal of water from muscle. As there is a paucity of research on the kinetics of the dehydration process occurring during dry‐aging of beef, this paper comprehensively reviews models used to describe drying kinetics in other beef products, in order to gain insights regarding the key factors that impact water removal from meat. Consideration is given as to how the specific conditions during dry‐aging such as air flows used (approximately 2 m/s), high air relative humidity, low temperature, and meat geometry will influence the kinetics of the drying. With regard to modeling, equations derived from Fick's second law of diffusion (e.g., thin‐layer models) have been used to describe the drying kinetics of small‐sized meat products. However, to apply Fick's law to dry‐aging, some different considerations may need to be evaluated such as: tridimensional geometry (i.e., whole muscle); uniform initial moisture content; isotropic diffusion; negligible shrinkage;and a combination of internal and external resistances. [ABSTRACT FROM AUTHOR]

The jet flow fields reported on in this paper were created by an unconventional gun head intended for polymer powder flame deposition. These flow fields are discussed in earlier papers by Payne et al. This paper reports on how the air or CO2 used in place of propane with this gun head mixed inertly with an isothermal coax­ial air jet. Flow visualization with a sheet of laser light described by Payne et al. showed that the jets, air or CO2, emanating from the propane nozzles were rapidly entrained in the coaxial air jet regardless of the presence or absence of a particle stream from the central nozzle. A gas analyzer measured the gas composition in the flow field downstream of the entrainment volume. The time-averaged CO2 concentration on the nominal centreline of the jet was constant or nearly so. In contrast, the variation in CO2 concentration increased dramatically with the radius at which the gas was sampled, up to a radius of ∼1.5 cm at a distance of 10 cm from the nozzle, after which this fluctuation decreased to 0 at the edges of the flow field. The magnitude of these fluctuations also decreased with the axial distance changing from 10 to 30 cm. Again, the presence or absence of a particle stream from the central jet nozzle had very little effect on the amount of CO2 measured. The irregular entrainment of CO2 caused the variations in the CO2 measured in the flow field. [ABSTRACT FROM AUTHOR]

ABSTRACT Airflow around building-integrated photovoltaics (BIPV) has a significant impact on their hygrothermal behavior and degradation. The potential of reducing the temperature of BIPV using an underneath cavity is experimentally and numerically investigated in literature. Most of the models are oversimplified in terms of modeling the impact of 3D flow over/underneath of PV modules, which can result in a non-uniform surface temperature and consequently a non-homogenous thermal degradation. Moreover, the simultaneous presence of radiation and convection related to upstream wind, in addition to the combined impact of back-ventilation and surface convection, is barely addressed in literature. However, these simplifications can result in the unrealistic loading climate conditions. This paper aims to present a unique experimental setup to provide more realistic climate conditions for investigating the ventilation potential of the underneath. The setup consists of a solar simulator and a building prototype with installed PV, placed inside an atmospheric wind tunnel to control upstream wind velocity. Thermography is performed using an infrared camera to monitor the surface temperature of the BIPV. The potential of an underneath cavity with various cavity heights and PV arrangement is further investigated in this paper. The outcome would be eventually useful in the development of practical guidelines for BIPV installation. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The fuel cell system is modeled to investigate output factors including voltage, power, and system efficiency for various input elements including different fuel composition, the air and fuel temperature and their utilization ratios. The purpose of this study is to examine the proficiency of a tubular solid oxide fuel cell (SOFC) by simplification in modeling calculation which results in the minimum required data. An electrochemical model is defined at first, and different current losses types were calculated in the next step. In further papers the amount of air and fuel is known and in some of them operating temperature must be known. But in this study it is enough to know the current density and required generated power of the SOFC. Since the amount of reacted methane is almost equal to input value, after performing this calculation for several fuel cells and validating it, the most optimal value for methane output is evaluated and output parameters of SOFC are calculated, then results are validated. The effect of main factors, including system temperature, pressure, current density, air and fuel flow rates and air to fuel ratio on the SOFC efficiency, were studied. Modeling method of current study provides optimum air and fuel flow rate. [ABSTRACT FROM AUTHOR]

Electric devices has become a necessity in modern smart societies. The energy research community is continually exploring new solutions that can be employed as potential and reliable alternatives to satisfy future energy requirements in this context. Triboelectric/piezoelectric nanogenerators (TNGs/PNGs) are considered promising renewable energy harvesting technologies. TNGs/PNGs are gaining considerable research attention because of their advantages such as ease of fabrication, cost effectiveness, flexibility, lightweightness, long‐term‐durability, and excellent output performance. The TNGs/PNGs have enormous potential in harvesting energy from water waves (blue energy), airflow (wind energy), sound frequency (acoustic energy), vibrations/mechanical motions (such as body motions activities/sleeping), and in vivo body motions. These technologies are thus an "all‐in‐one package," which is a unique selling point. The advantage of this technology is that all sources are natural and abundant. This paper provides a review of the potential use of PNGs/TNGs and includes a description of the rise of nanogenerators, their underlying mechanisms, different materials used, various models, possible applications, and future prospects. Stored energy can be used to develop smart/informative technologies (as ultrasensitive sensors) and self‐powered biomedical science. Owing to their considerable effects, these harvesting technologies are expected to dominate the future smart world. [ABSTRACT FROM AUTHOR]

In order to make the moisture content monitoring more convenient and rapid during peanut drying process, the drying characteristics of peanut were investigated and a real‐time SVR moisture content monitoring model was established in this paper. The results showed that hot air temperature, initial moisture content, airflow rate and the layer height were the key factors on peanut drying, and the peanut variety showed little effect on drying. The SVR model exhibited a good performance with R2: 0.91, RMSE: 4.38, and bias: −7.5e‐3. Compared with the results of linear regression models and multilayer perceptron model, SVR model showed a better performance. In addition, the SVR model was validated by the drying data of other three varieties of peanuts. And the relative errors between the predicted values by SVR model and the measured values were within 20%, which suggested that SVR was a promising modeling algorithm for peanut drying. Practical application: Peanut drying is essential for peanut production due to its high moisture content at harvest (about 30–50% on the wet basis), which makes it susceptible to mildew, or even produces aflatoxins. Peanut has a special physiological structure. In the drying process, the peanut kernels are gradually shrunk, which makes the air layer volume between the shell and the kernel gradually increases, thus hindering mass and heat transfer and leading to its different drying characteristics from other grain and oil crops. Furthermore, it is necessary to monitor the moisture content changes of peanut during deep bed drying to ensure the drying uniformity and prevent energy waste. Therefore, the drying characteristics of peanuts were studied and a moisture content prediction model for deep bed drying was established to assist the actual drying process. [ABSTRACT FROM AUTHOR]

To understand the instantaneous particle deposition in nasal cavity, effects of two injection models on particle deposition characteristic were discussed in this paper. Based on a realistic human nasal cavity geometry obtained from CT scans, a comparison of deposition pattern in the nasal cavity between single injection and continuous injection was investigated through the Lagrangian approach. The instantaneous airflow field was simulated with the tidal volume of 159 and 318 mL by two sine wave curves at inlet. For the case of single injection, particles have finished deposition in the first half of inhalation, and a negative correlation between the tidal volumes and deposition can be observed when the particle diameter was larger than 10 µm. Moreover, particles were mainly deposited in the turbinate area that was beneficial for aerosol therapy. The inertial parameter was not suitable to predict the particle deposition in the case of single injection. With respect to continuous injection, a reduction in total deposition caused by the deceleration process of inhalation can be observed after 1.5 s. The deposition was closely associated with the time-varying flow field, and particles were mainly deposited in the anterior region and turbinate area. Besides, the particle deposition increased with the inertial parameter for continuous injection. The results indicated that the injection modes had an influence on both the total deposition and local deposition pattern in the nasal cavity. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A water jet with an air ring protective layer is a promising rock‐breaking and cutting rate improvement method in submerged environment, such as oil–gas drilling. The jet flow field characteristic determines the jet impinge performance and is affected by nozzle structure parameters. In this study, the water jet flow with air ring under submerged environment was numerically simulated. The jet flow field structure with air ring was obtained by analyzing the distributions of jet velocity and air content at different cross sections. The effects of several critical nozzle structure parameters on jet isokinetic core length and axial velocity were investigated by adopting the orthogonal design method. The results show that the jet flow field structure with air ring in radial direction includes a high‐speed water jet zone, air ring protective layer, and air–water mixed zone, having the advantages of concentrated energy in axis region, long core section length, and low‐velocity attenuation. The influence degrees of nozzle structure parameters on jet core section length and axial velocity at X = 0.3 m are: length‐diameter ratio > outlet diameter > conic angle > air nozzle diameter > water‐air nozzle spacing and outlet diameter > length‐diameter ratio > conic angle > water‐air nozzle spacing > air nozzle diameter, respectively. The jet core section length and axial velocity both increase exponentially with the increasing outlet diameter, both first increase rapidly and then slowly decreases with the increase of conic angle and water–air nozzle spacing. There is the optimal conic angle of 15° and appropriate water–air nozzle spacing of 3–5 mm. With the increase of length–diameter ratio, they both first decrease rapidly and then slow down, indicating that conical nozzle is more suitable for water jet with air ring. And 0.9–1.2 mm is proper for the air nozzle diameter. [ABSTRACT FROM AUTHOR]

Small-scale, fast-evolving airflow disturbances, possibly due to upstream building clusters, are known to affect aircraft landing at corridor 25RA of Hong Kong International Airport (HKIA), China, under southerly or southwesterly winds. The paper presents a new algorithm, based on the concept of coherent integrated differential velocity (CIDV), for the automatic alerting of such hectometric (scale of hundreds of metres) turbulence features using short-range LIDAR (SRL) scans at 30 m radial resolution and an observation frequency of around every 20 s by Hong Kong Observatory (HKO). The CIDV identifies the cumulative effect of coherent patches of radial velocity changes occurring along the landing flight path by comparing two consecutive subminute SRL scans. Verification was conducted between June and September 2017 against a selection of relevant pilot reports, with a positive skill level observed over the whole range of the CIDV thresholds considered. When simulating a realistic setting where the SRL would issue alerts in conjunction with HKO's operational Windshear and Turbulence Warning System (WTWS), the CIDV algorithm would bring a gain in hit rate between 5% and 25%, with a corresponding increase in alert duration between 0.4% and 20%. The chosen CIDV threshold of 0.4 m·s-1 nautical mile (nm) can be physically interpreted as an average radial velocity change of 4.0 m·s-1 sustained over a distance of < 200 m (or between 2 and 3 s of flight), which agrees with reported values of crosswind changes considered significant for a landing aircraft and also pilots' perception of the characteristics of such events. [ABSTRACT FROM AUTHOR]

In this study, we designed a 5HLN‐R‐50 electric grain dryer with internal circulation of the drying medium based on the analysis of drying medium enthalpy and humidity status variation diagrams. We aimed to reduce the dryer energy consumption and exhaust gas emission. Using clean electric energy instead of a conventional dryer heat source, the drying system can cyclically dry high‐moisture grain with zero emissions. The experimental results indicate that the condensation effect is suitable when the ratio of the cool and hot air flows is 6:1 at a heat transfer coefficient of the condenser of 79.5 W/(m2.K) and a specific heat consumption of 3,916 kJ/kgH2O when compared with the Chinese standard of 7,500 kJ/kgH2O, that is, a maximum energy savings of 48%. This paper proposes a novel technological method and idea, studies the differences in energy efficiency, emissions reduction and clean production, and provides a reference for replacing the conventional grain dryer heat source of coal with electricity. Practical applications: This drying system is applied in circular grain drying; a corn drying experiment indicates that compared with the specific energy consumption stipulated by the national standards of China, the highest energy savings is 48%, and zero release nonpollution is shown. The state parameters of the dried material and drying medium are displayed graphically in real time, and the operating parameters of the drying process are intuitively tracked in real time and automatically adjusted. [ABSTRACT FROM AUTHOR]

Methanol is a convenient liquid fuel for fuel cells, but is not converted as efficiently into electrical energy as hydrogen. This is due to the slower reaction of methanol at the anode as well as to methanol permeation. When optimizing the direct methanol fuel cell (DMFC) process, methanol concentration and flow rate, current density and air flow rate must also be taken into account. A high methanol concentration facilitates dynamic operation up to high current densities, but also leads to high methanol permeation. The air flow rate must be adjusted so that the cooling effect of evaporating water is balanced by the heat produced in the cell. Therefore, a cell with low permeation must be operated at low air flow rates to achieve autothermal operation at elevated temperatures, which can in turn reduce cell performance. For each current density, there is an optimum amount of methanol feed. In this paper, we show how these effects have to be balanced using air‐flow rates calculated to ensure thermal equilibrium. It is possible to achieve electrical cell efficiencies of up to 44% in a self‐heating DMFC. Another small increase in efficiency can be achieved by using humidified air at the cathode. [ABSTRACT FROM AUTHOR]

Co‐gasification of wood mixed with 20% (mass fraction) of polyethylene (PE) in a two‐stage NOTAR® fixed‐bed gasifier was studied in the present paper. The ratio of air flow injected in the pyrolyzer and air flow injected in the oxidation zone is called the air ratio (AR). The AR of 0.35, 0.43, and 0.49 were used for test runs. Mass and energy balances were established. The study showed the feasibility of co‐gasification of wood mixed with 20% of PE in the two‐stage gasifier. However, considerable quantity of residues rich in fixed carbon content (17% of the fuel mass and 69% of fixed carbon content) was produced due to a low reactivity of the charcoal obtained after the pyrolysis. AR increasing reduces the gas CO content due to overconsumption of char at the pyrolysis stage. H2 and CH4 highest values are obtained for the intermediate AR = 0.43 which maximized the LHV, energy efficiency, and carbon conversion with respectively 4674 kJ/Nm3, 64.35%, and 74.52%. Low reactivity and carbon content of the pyrolysis char likely lead to lower performance of co‐gasification of PE mixed with wood compared to wood gasification. [ABSTRACT FROM AUTHOR]

Investigations of pulmonary airflows in respiratory systems are important for the diagnostics and treatment of pulmonary diseases. For accurate prediction of the flow field in an airway, a numerical simulation must be conducted using the true geometry from computed tomography (CT) data. Flow simulation is still a difficult task because of the mesh generation process and preprocessing setup procedures. In this study, we developed a voxel image‐based simulation method using an automatic detection algorithm for airway outlets to simplify the simulation process and improve its applicability in the medical field. Our approach is based on the lattice Boltzmann method with a topology analysis algorithm, which can preserve all raw information from the original CT images and give an accurate flow field inside the airways. Our method can reproduce the essential flow features inside airways, is highly efficient, and decreases the overall processing time. Thus, it has a great potential for future real‐time airflow analyses to provide airflow information to medical experts. Highlights: This paper proposed a voxel image‐based simulation method with a novel automatic outlet‐selecting algorithm to calculate the velocity and pressure of physiological flows in multi‐generation–branched airways.Our approach simplifies the simulation process by automatically applying the boundary conditions to large numbers of outlets and minimizes the time‐consuming mesh generation process.Our proposed method has considerable potential for real‐time simulations improving the applicability to patient‐specific medical diagnostics and treatments. [ABSTRACT FROM AUTHOR]

Summary: Robust control of parameter‐dependent input delay linear parameter‐varying (LPV) systems via gain‐scheduled dynamic output‐feedback control is considered in this paper. The controller is designed to provide disturbance rejection in the context of the induced L2‐norm or the L2−L∞ norm of the closed‐loop system in the presence of uncertainty and disturbances. A reciprocally convex approach is employed to bound the Lyapunov‐Krasovskii functional derivative and extract sufficient conditions for the controller characterization in terms of linear matrix inequalities (LMIs). The approach does not require the rate of the delay to be bounded, hence encompasses a broader family of input‐delay LPV systems with fast‐varying delays. The method is then applied to the air‐fuel ratio (AFR) control in spark ignition (SI) engines where the delay and the plant parameters are functions of the engine speed and mass air flow. The objectives are to track the commanded AFR signal and to optimize the performance of the three‐way catalytic converter (TWC) through the precise AFR control and oxygen level regulation, resulting in improved fuel efficiency and reduced emissions. The designed AFR controller seeks to provide canister purge disturbance rejection over the full operating envelope of the SI engine in the presence of uncertainties. Closed‐loop simulation results are presented to validate the controller performance and robustness while meeting AFR tracking and disturbance rejection requirements. [ABSTRACT FROM AUTHOR]

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Icing threatens the safe and stable operation of transmission lines. Accurate prediction of the icing process of conductor can help the work of anti-icing and disaster reduction of transmission lines. Generally, the icing of conductor is accompanied by the torsion process of conductor. Because of the interaction of conductor torsion and icing, there is a big difference of the icing shape and rate between different positions on a transmission line. In order to improve the accuracy of numerical calculation of conductor icing, a dynamic numerical calculation model of conductor icing torsion is established based on hydrodynamics and basic mechanics in this paper. Comprehensively, the model takes the effects of torsion angle and torsion icing shape on the icing process into consideration, including the effects on airflow filed and trajectories of water droplets in the air. Through the simulation, the change law of the torsion angle at different positions of the conductor, the influence characteristics of the conductor torsion on the icing process, and the differences of the icing torsion of conductor under different environmental parameters are analysed. The results show that, compared with the condition without torsion, the collision range of water droplets on the conductor is larger under the torsion condition, the average value of collision efficiency β1 is higher, and the icing rate is faster. The larger the wind velocity and the median volume diameter of water droplets in the air, the faster the conductor icing torsion development. [ABSTRACT FROM AUTHOR]

In this paper, we consider the synchronization of a class of nonlinear network flow systems. Motivated by air distribution problem in air conditioning and mechanical ventilation (ACMV) systems, we propose a class of coupled nonlinear multi-agent systems that can model a wide class of network flow systems, including air flow in ACMV systems, water flow in irrigation systems, traffic flow in transportation systems, and so on. Then we consider the synchronization problem for the class of nonlinear multi-agent systems and propose cooperative controllers for the system. Based on graph theory, we derive conditions on the initial values of the state and the control input such that synchronization can be achieved. An application to air ventilation is provided to demonstrate the effectiveness of the cooperative controllers. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper proposes a multiple-model solution to the problem of controlling an air heating fan subject to faults. These faults are modeled by means of an abnormal unknown airflow input rate which the nominal controller is not designed for. Moreover, the average temperature of the air flowing through the system, which can be seen as an offset on the corresponding dynamics, is (slowly) time-varying and highly dependent on the ambient temperature. The fault-tolerant control (FTC) method adopted makes use of set-valued observers (SVOs) to invalidate possible models of the system. Unlike classical fault detection, this approach does not rely on residuals to detect abnormal system operation. This fact allows to reduce the conservatism of the solution and enables a straightforward design from the faulty and nominal models of the plant. Moreover, the absolute distinguishability concept is used to derive input signals that bolster the detection of faults. Although SVOs require heavy real-time calculations that hinder its implementability in systems with low computational power, it is shown that the architecture of the FTC strategy proposed is highly parallelizable and, thus, may take advantage of standard multi-core processing units. Experimental results are presented. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Cyclonic-Static Micro-bubble Flotation Column (CSMFC) has been widely used in fine mineral separation. The micro-bubble generator, as a key unit of this flotation column, is used to produce micro-bubble which designed based on the principle of gas liquid jet pump. Unlike the other jet pump, the performance of micro-bubble generator not only focuses on the air suction volume flow rate, but also includes the size and distribution of bubbles. In this paper, the performance of bubble generator is studied both experimentally and numerically. Three-dimensional numerical simulations employing the Eulerian two-phase flow model and S-N drag model by Fluent 14.0 software is carried out. The experimental and Computational Fluid Dynamics results, of air volume flow rate, match closely with each other. The maximum relative error between experiment and numerical simulation is smaller than 7.6%. Then these numerical models are utilized in simulating the 3D flow field of micro-bubble generator with different nozzle-to-throat spacing. Thirteen sets of simulations were conducted to explore the influence of the dimensionless nozzle-to-throat spacing (0-3) on air volume flow rate, bubble diameter and distribution. The results demonstrate that the performance of bubble generator is optimal when the dimensionless nozzle-to-throat spacing is over 1.25-2.5 while the water volume flow rate is fixed to 50m3/h. In this range, the bigger air suction volume flow rate, the smaller bubble diameter and higher bubble distribution uniformity index, which are beneficial for fine minerals flotation, were obtained. [ABSTRACT FROM AUTHOR]

Humidification and dehumidification (HDH) desalination units compared with the other thermal desalination systems have relative advantages due to working under ambient pressure and low temperatures and are more attractive. In this research, the application of an HDH desalination unit with indirect‐contact of air and water streams in a steam power plant is investigated. To increase the energy efficiency of the system, a closed air cycle has been considered. Also, by application of the closed water cycle in the humidifier, the recovery rate of the desalination unit increases according to the concentration of discharge flow. The flow rate of boilers blowdown in the studied steam power plant is around 2.2 kg/s and can be used as a unique source of required thermal energy in the desalination system to produce freshwater from power plant chemical effluents. On the basis of the available cooling water (30 m3/day), this stream is considered as the limiting flow in the modeling. The detailed design of different parts of the desalination unit, including the humidification tower, condensers, wet air circulation fans, the required pumps, and the heat exchanger, is presented in this study. The maximum production of freshwater and the minimum energy intensity are obtained for the circulating air flow rate of 4 kg/s. By 14% recovery of lost steam in the power plant, 20.8 m3/h of desalinated water is produced. The gain output ratio and the energy intensity of the system are 1.025 and 2201 kJ/L, respectively. The production cost with the proposed indirect‐constant HDH system is equal to 0.56 $/m3 of freshwater. [ABSTRACT FROM AUTHOR]

Considering that nearly 39% of the total CO2 emission released into the atmosphere today are thought to be due to the energy consumed by buildings, the importance of taking measures through buildings to combat global warming is evident. Therefore, the concept of nearly zero‐energy buildings (NZEB) is come to the forefront. Building integrated photovoltaic thermal (BIPV/T) systems are used to enable buildings to generate their own energy. However, buildings have limited facade and roof areas required for BIPV/T systems. Therefore, in this study, various configurations of bifacial (double‐sided) and monofacial (single‐sided) panels were compared to investigate ways to enhance the efficiency of BIPV/T systems. Different air flow velocities and varying air gap distances were tested for both panel types. By placing a reflective surface on the wall behind the bifacial panel, the electrical efficiency of the bifacial panel was increased and proven through PVsyst analysis. Both panels provided maximum heat efficiency at the shortest air gap distance under high air flow conditions. In addition, it was shown in both the experimental setup and Comsol CFD analysis that it provides significant benefit in the thermal energy load of the building when heating the interior environment in winter. In terms of electrical power production surplus, the bifacial panel outperformed the monofacial panel in all configurations, with a minimum advantage of 8.33% and a maximum of 12.73%. Additionally, the maximum electrical efficiency was obtained from the bifacial panel in configurations with the longest air gap distance. Using the bifacial panel in the BIPV/T system with the shortest air gap distance during the heating season and the longest air gap distance during other seasons can provide the highest efficiency for the building throughout the year. [ABSTRACT FROM AUTHOR]

This paper reviews some aspects of wind tunnel experiments on sand-transporting winds. It follows previous papers that have discussed the influence of the outer region of the boundary layer on wind velocity measurements. This influence was quantified with the use Coles' Wake function. In this paper this correction is applied to six previously described wind velocity profiles. An attempt is made to calculate the profile parameter ∏ from these measurements. The values found were not consistent with the expected ∏, which was determined by Coles for clean air flow. This value (∏= 0.55) was assumed to be valid in previous analyses for sand-transporting winds. Evidence for a mutual dependency of friction velocity and profile parameter is presented and the difficulty in determining u[SUB*] is pointed out. It is suggested that the constant stress region of the boundary layer should be kept large enough for measurements when Coles' Wake function is not to be used in the data analysis. [ABSTRACT FROM AUTHOR]

The multi‐operating robustness of triboelectric nanogenerators (TENGs) is still an awkward issue that must be solved to achieve practicality and industrialization. Here, an aerodynamics‐based TENG (AB‐TENG) is developed by combining it with a propeller and rotor, which can switch automatically between contact and separation mode. The separation speed can be reduced to 150 rpm by optimizing the spring stiffness coefficient, which maintains 95.18% of the electrical output after continuous operation for more than 1.378 million cycles. Combining with power management circuit, these capacitors of 0.56, 1, 3.3, and 10 mF can be charged quickly to 3 V within 7.3, 9.3, 16.7, and 43.4 s, respectively. In addition, AB‐TENG can power 6 digital hygrothermographs in parallel by harvesting irregular airflow or drive one Bluetooth‐enabled, 6 commercial LED bulbs of 3 W or 240 green LED lamp beads in parallel, respectively. This work provides an effective strategy to improve the multi‐operating robustness of TENGs, and more importantly, to overcome the mechanical durability and electrical stability difficulties of the technique at high rotational speed caused by abrasion limit of triboelectric materials, and may reveal its potential in the distributed energy and Internet of Things. [ABSTRACT FROM AUTHOR]

Airflow windows (AFWs) help to stabilize the thermal environment in the perimeter zone and also allows for switching between solar‐shielding and solar heat acquisition operations. This is based on the method of channelizing the air discharged from its cavity layer, either by using a total heat enthalpy exchanger and choosing to exchange heat or otherwise. It has a certain thickness owing to the blinds that are installed in its cavity layer. The purpose of this research is to develop a window system that uses electrochromic (EC) glass, instead of blinds, as a solar‐shielding device. This study also provides the specifications of the window system of reduced thickness. The performance of the window system is assessed by CFD analysis. The solar heat gain coefficient (SHGC) of the proposed window system is found to range from 0.083 to 0.268 and its solar radiation properties can be controlled in a flexible manner. These characteristics contribute to an improvement in the building environmental performance in the form of climate‐adaptive building shells (CABS) in places with four distinct seasons such as Japan that require solar‐shielding to reduce the cooling load in summer and solar heat gain to reduce the heating load in winter. [ABSTRACT FROM AUTHOR]

Noninvasive and accurate measurements are essential to study the reactive flows in aeronautical engines. This paper reports the results of a unique measurement campaign providing the temperature flow field in a large‐scale facility turbomachine test rig using spontaneous rotational Raman scattering technique. Different planes of interest and operating conditions are probed, showing good agreement with thermocouple measurements. Fast temperature variations (>7.7 kHz) could be probed thanks to synchronization of the laser pulse with the rotor clock. The results outline the performance of in situ Raman technique to investigate steady and unsteady flows in turbine's conditions. [ABSTRACT FROM AUTHOR]