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Basis weight distribution of melt-blown fibrous web is attracting considerable interest because it directly affects the application performance of nonwovens. Basis weight distribution is strongly determined by the air velocity distribution on the top surface of the collector. However, how the mentioned air velocity distribution affects basis weight distribution is still unknown. Measurement of the mentioned two distributions is the first step to investigate the influence mechanism. Thus, this work measures air velocity distribution on the collector under different processing conditions. Then the fibrous web is fabricated under same conditions. After fabrication, the basis weight distribution of fibrous web is analyzed by using image analysis method. The effects of processing conditions, including velocity of air jet and suction, die-to-collector distance, and pore size of the collector, on the air velocity distribution and basis weight distribution are quantitatively analyzed. The results demonstrate that higher suction speed and air jet velocity, smaller die-to-collector distance, and larger pores of the collector result in higher air velocity on the top surface of the collector. On the other hand, higher suction speed and air jet velocity, larger die-to-collector distance, and smaller pores of the collector create evenly distributed basis weight. In addition, the correlation between basis weight distribution and air velocity distribution is discussed based on the Spearman correlation analysis method. High correlation demonstrates that air velocity and basis weight display similar distribution on the collector. Namely, both of air velocity and basis weight in the central zone are larger than those in the fringe zone on the collector. [ABSTRACT FROM AUTHOR]

In this paper, we report an optimized CMOS compatible MEMS thermoresistive calorimetric air velocity (TMCV) sensor to measure small air velocity in an indoor environment for the application of human thermal comfort sensing. The sensor is comprised of two upstream thermistors, two downstream thermistors, and a micro-heater placed in between the upstream thermistors and downstream thermistors. The dimensions of the sensor were optimized to achieve better linearity and accuracy in the tiny air velocity (−1 m/s to 1 m/s) range based on the CFD simulation. Furthermore, to reduce the heating power and increase the normalized sensitivity, the sensor was completely released from the substrate using the DRIE process. The sensor was successfully tested both in a lab in a wind tunnel and a real indoor environment. The sensor achieved a maximum sensitivity of 340.2 mV/(m/s), and normalized sensitivity, with respect to heating power and gain, of $354.37~\mu \text{V}$ /(m/s)/mW within −5 m/s to 5 m/s air velocity range. The normalized sensitivity achieved by our sensor is much higher than most of the reported TMCV sensors. Besides, the sensor obtained a good linearity (${R}^{2}=0.9996$) and accuracy (±0.0236 m/s) within the small air velocity range meeting the standard accuracy requirement (< ±0.05) of ASHRAE-55 and ISO-7726 standards. Moreover, the packaged TMCV sensor was successfully tested in an office to measure very small air velocity ($0~\sim ~0.5$ m/s) produced by the HVAC system. The experimental results indicated that our sensor is quite suitable for smart HVAC system integration in the era of the Internet of Things (IoT). [ABSTRACT FROM AUTHOR]

In the current global endeavor of energy conservation, waste heat recovery is a key contributor and deserves more focused attention. Process industries demand high energy inputs and often generate high-temperature exit gases, which can potentially be considered as secondary energy sources. If such waste heat is recovered, considerable savings in the net energy demand is possible. This report, based on this objective, details the outcome of an experimental study conducted in a vertical riser where solid particles, through a co-current contact with hot air, recover the energy content of the gas. Fabricated experimental setup is a prototype of suspension preheater (riser–cyclone combination) used in a modern-day cement industry. Data relevant to hydrodynamic and heat transfer patterns are collected as not much information is available in the literature on these aspects. Empirical correlations for acceleration length and heat transfer coefficient in dimensionless form, are reported and are recommended for not only cement but for diverse other industries, where waste heat recovery is possible. [ABSTRACT FROM AUTHOR]

The construction of flats is one of the steps toward fulfilling the need for housing in Jakarta and other big cities in Indonesia. This study investigated the thermal problems that focus on air movement in residential units of flats due to window dimensions that cannot accommodate the air velocity that surrounds the buildings because of monotonous window dimensions and the high elevation of the residential units. The position of the interest of this research is on the search for window dimensions that allow comfortable air movement in the residential unit. Based on these problems and interest, the pertinent issue is the design of window dimensions within the facades of the buildings according to the actual air velocity and the elevation of the residential units. The selected object of study was the Jatinegara Barat flats, a block of high-rise flats located in the middle of East Jakarta, Indonesia, which is adjacent to the river. We used a quantitative deductive methodology for the problem analysis via mathematical and simulation methods that use the Ansys R1 2020 software. The final results showed that the relationships between window dimensions, air velocity, and the elevation of residential units can be mapped horizontally and vertically by paying attention to the locations of the window openings with respect to the wind direction and building layout. The horizontal and vertical maps showed repetition of the window dimensions every four floors, with the four floors in the center of the building (read vertically) having window dimensions one-quarter smaller than the four floors above and four floors below.

The FDS (Fire Dynamic Simulation) software is used to simulate the air flow field under normal ventilation condition in petrochemical pipe gallery tunnel, the change regularity of characteristic parameters of flow field at different heights in the tunnel is obtained. The results show that as the height increases, the average velocity of air on cross section of tunnel at different heights is 1. 75, 2, 3. 5, 7. 5 m/s, respectively, and the highest velocity reaches 3.5, 4, 7, 15 m/s. In the design, combustible or toxic gas detectors should be set in the middle of every two jet fans, and every two gas detectors are separated by 80 meters. When the jet fans are opened for 260 seconds, staffs are advised to wear personal protective equipment before entering the tunnel for routine patrol. [ABSTRACT FROM AUTHOR]

Frosting has always been a crucial problem for air source heat pumps (ASHPs) operated in heating mode. Quantitative evaluation of frosting is of vital importance to the development of technologies against frosting. Although frosting maps have been developed in many studies, they are specific for unique systems. To evaluate the frosting performance of arbitrary system, a semi-experimental method, to depict frosting evaluation plot, was proposed in the present study. In the frosting evaluation plot, frosting region was clarified, and the frosting driving forces with the effect air temperature and relative humidity (RH) were evaluated, through theoretical calculation of Gibbs free energy change. After that, experiments were conducted to verify the frosting evaluation plot, and the results demonstrated the present method was feasible. In some experimental cases, the inlet segment of the heat exchanger escaped from frosting but the outlet segment frosted. As implementation of the semi-experimental method, the methodology was utilized to clarify the air temperature and RH ranges causing uneven frosting. In addition, the frosting evaluation plot with impact of air velocity was drawn. The results suggested that, increased air velocity restrained frosting, and reduced the chance of uneven frosting. [ABSTRACT FROM AUTHOR]

At present, according to the extraction plan in the year 2020 of Duong Huy Coal Company - Vinacomin, the mining is divided into three main zones: Central Zone extracts 06 faces; South Zone extracts 2 faces and Northeast Zone extracts 2 faces. The designated total production of all zones is 1,880,000 tons/year. To ensure the production of each mining zone, exhaust fan stations are installed at ventilation roadway adits with a total of 05 main fan stations. However, in the near future, to ensure and maintain production activities, the mine is being planned and operated using 03 main fan stations. The calculation results for the reasonable working mode of fan stations are as follows: for fan station FBCDZ-8-№32B at level +47 m, airflow is 167.69 m3/s and air pressure is 243.74 mm H2O; for fan station 2K56-№30 level +40 m, airflow is 123.37 m3/s and air pressure is 324.79 mm H2O; for fan station FBCDZ-8-№32B at level +44 m, airflow is 167.69 m3/s and air pressure is 354.99 mm H2O. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the cooling effect of a spray fan in an indoor hot environment. An experimental workplace with a thermal environment of high temperature and radiation intensity was set up. The hot environment of the experimental workplace could not meet occupational health requirements when the heat source temperature exceeded 150°C. The effects of air velocity and relative humidity on the natural wet bulb temperature, black globe temperature and wet bulb globe temperature (WBGT) were investigated. The maximum reduction of the WBGT was about 1.7°C, with an air velocity increase by 1 m/s. There was a notable cooling effect on the hot environment for low air velocities (e.g. 0–2 m/s), while the cooling effect only increased slightly for high air velocity (e.g. 2–5 m/s). We also found that the indoor WBGT declined by 0.2–0.8°C when the relative humidity was increased by about 10%. These results may provide guidance for reducing heat stress in industrial hot environment. [ABSTRACT FROM AUTHOR]

The effects of different drying temperatures and air velocities on the drying behavior, quality, and nonvolatile compounds (NVCs) transformation of Citri reticulatae pericarpium (CRP) were investigated. Results showed that the drying time shorted with increasing drying temperature and air velocity; however, the energy consumption was lowest at 65 ℃. The rapid moisture migration led to a porous structure, increased frangibility and thickness, and decreased hardness. Rising air velocity increased the curl, which properly protected the volatile oils. The increased drying temperature also changed the NVCs, as evidenced by the reduced amino acid, ester, phenolic, and carbohydrate content in CRP. As for hesperidin, it reaches its maximum at 65°C, caused by the transformation of flavonoid metabolism. Furthermore, the analysis demonstrated that temperature and air velocity have interactions besides the individual effects. By considering both drying time and quality, the desired CRP products were obtained at 65°C and 6 m/s through a comprehensive evaluation. • CRP at 65 ℃ and 6.0 m/s was optimum according to the comprehensive evaluation. • The interaction of temperature and air velocity had more impact than each alone. • Temperature is the primary factor influencing the active component of CRP. • Rising air velocity increased curling and protected the volatile oils better. • Changes in hesperidin content relate to flavonoid metabolic transformation. [ABSTRACT FROM AUTHOR]

Nutritional test pens are commonly used to segregate and geolocate birds in commercial-scale broiler houses to control spatial variation from the environment. Pens should subject test birds to similar environmental conditions as birds roaming free in the house, however, discussions on pen construction materials, design, and placement have focused on durability and handling with little regard for the pen's thermal environment. Simulated birds were constructed with a metal bowl and a light bulb heat source to mimic the heat generation of large commercial broilers. Bowl surface temperature (BST) was measured as a model for the surface temperature of a broiler housed in a nutritional pen. Effects of panel open area (100% (control), 89%, 85%, 70%, 50%, and 30%) and air velocity (2, 3, and 4 m/s) were factorially tested on BST in a wind tunnel. Panels with an open area of less than 70% were different (P < 0.0001) from free air (100% open area). There was a difference of 5°C (9°F) for BST between the most restrictive panel (30%) and free air (100%), demonstrating a large difference in the thermal environment that birds might experience if air is restricted. Air velocity treatments were different (P < 0.0001) with mean BST increasing as air velocity decreased. Panels should be constructed with open areas greater than 70% accounting for structural framing and other obstructions as well as expected dust accumulation. While pen durability and handling are important for on-site success, these parameters should not overshadow restrictive airflow pen designs that would potentially alter thermal environmental conditions in nutritional treatment comparisons. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the authors or the U.S. Department of Agriculture. [ABSTRACT FROM AUTHOR]

In India, railways still continue to be the most prominent means of transport, especially non-air conditioned railway that carries around 3.5 billion people every year. Thermal comfort in these non-air-conditioned trains is predominantly influenced by windows and fans. The present study orients around the effect of fan air as well as naturally ventilated air on thermal comfort of passengers. The study is part of a field survey followed by an experimental investigation that was carried out in non-air-conditioned railway coaches during summer afternoon, with more than 1500 subjects of different gender and age category. The study significantly contributes in defining an elevated acceptable range of comfort air velocity inside a moving stock. The mean threshold air velocity where passengers responded a neutral PCV (passengers' comfort vote) is found to be 2 m/s which is much higher than conventional standards for enclosed static buildings and premises. The clear dominance of behavioral adaptation has been noticed in expression of thermal comfort by the passengers. This strengthens the idea of adopting some alternative method to deal with thermal discomfort of non–air-conditioned railway passengers. Here a novel term as 'zone of independence' (ZoI) has been defined at which the effect of air velocity becomes independent on passengers' comfort vote. This ZoI can significantly be utilized while optimization of thermal comfort in an ICF railway coach. • Thermal adaptation is more dominant in case of passengers as compared to building or office occupants. • Acceptable air velocity for thermal comfort at different relative humidity values varies within a range of 1.1 m/s to 2 m/s. • For higher humidity bands slightly lower air velocity preference has been recorded. • Need to redesigning of air velocity distribution for the existing Indian railway non-air-conditioned passenger coaches. [ABSTRACT FROM AUTHOR]

Turkey’s poultry industry has experienced significant growth in recent years, resulting in the construction of many new production facilities. It is important to maintain optimum environmental conditions for a profitable production. In this study, temperature, relative humidity and air velocity distribution inside a broiler house were analysed. Computational Fluid Dynamics (CFD) simulations (numerical method) and direct measurements (experimental method) were used to determine the appropriate indoor environmental conditions. Simulated values were validated by comparison with the measured values using the normalised mean square error (NMSE). The measured and predicted parameters of temperature, relative humidity and air velocity at birds’ height, human height, and roof height upon comparison gave average NMSE values of 0.139, 0.181 and 0.090, respectively. The results showed a good agreement between simulated and measured values as obtained NMSE values were less than 0.25. In conclusion, CFD simulation can be used as an alternative method for the analysis of poultry house indoor environment. A better understanding of indoor environment conditions in poultry house provides useful information for manufacturers and end users for better management decisions.

This paper presents a device for introducing air inside a room with the novelty of double-exponential profile of the distributor. This allows entering the rooms of large quantities of blow-in air with low velocities, with the result of possible use in locations with a high required air exchange. In the Laboratory of Ventilation and Air Conditioning of the Technical University of Cluj-Napoca, it was designed and built an experimental stand in order to investigate the velocity field of a double-equal strength (double exponential profile) inlet device for spatial air-distribution. There are presented the measurements that were performed in the laboratory in order to establish the velocity field and the spatial distribution of air. The proposed solution can be used in many applications to provide high rates of air through the ventilation systems.

Biomassa dapat dimanfaatkan menjadi energi alternatif sebagai bahan bakar dalam bentuk briket yang mengandung unsur utama atom karbon (C) yang berasal dari kandungan selulosa, hemiselulosa dan lignin. Karakteristik briket dapat dilihat dari beberapa hal diantaranya suhu karbonisasi dan kecepatan udara yang berpengaruh terhadap laju pembakaran briket, sehingga tujuan penelitian ini adalah mengetahui suhu karbonisasi dan variasi kecepatan udara terhadap laju pembakaran briket campuran sekam padi dan tongkol jagung. Tahapan pembuatan briket dengan cara pengeringan bahan, karbonisasi pada suhu 200°C, 225°C, 250°C, 275°C, penghalusan dan penyaringan bahan dengan ukuran butir 40 mesh, pencetakan briket dengan konsentrasi pencampuran sekam padi dan tongkol jagung 50:50, dan pengeringan briket. Pengujian nyala briket dilakukan dengan variasi kecepatan udara 0,8 m/s, 1,1 m/s, 1,2 m/s, 1,3 m/s ,1,4 m/s. Hasil penelitian menunjukan briket yang dibuat dengan suhu karbonisasi yang tinggi maka laju pembakaran semakin lambat karena semakin rendahnya zat volatile matter dengan laju pembakaran 0,46 gr/menit pada suhu karbonisasi 225°C dengan v = 1,4 m/s. Dan semakin besar kecepatan udara maka laju pembakaran akan semakin kecil karena panas temperatur akan ikut terbuang dengan semakin besarnya kecepatan udara, dengan laju pembakaran optimum 0,42 gr/menit dengan kecepatan udara 1,4 m/s pada briket suhu karbonisasi 225°C. Biomass can be utilized as an alternative energy as fuel. Biomass contains the main elements of carbon atoms(C) derived from the content of cellulose, hemicellulose and lignin. Characteristics of briquettes can be seen from several things incluiding the carbonization temperature and air velocity affect the burning rate of briquettes, so the purpose of this research is to know the effect of carbonization temperature and air speed variation of the burning rate briquette mixture of rice husks and corn cobs. The research methodology includes material drying, carbonization at 200 ° C, 225 ° C, 250 ° C, 275 ° C, refining and filtering of 40 mesh materials, briquette printing and pressing with concentration of material mixing rice husks and corn cobs 50:50, and briquette drying. Further testing of flame briquettes with air velocity 0,8 m/s, 1,1 m/s, 1,2 m/s, 1,3 m/s and 1,4 m/s. The results showed the briquettes are made by high carbonization temperature then the slower burning rate because of the low volatile matter with burning rate 0,46 gr/menit on carbonization temperature 225°C with air speed 1,4 m/s. The greater the air velocity, burning rate will be smaller because temperature heat will be wasted along with increasing air speed and optimum burning rate 0,42 gr/menit was found on speed 1,4 m/s with carbonization temperature briquettes 225°C.

This paper presents a detailed account of computational fluid dynamics (CFD) simulations undertaken to investigate the influence of intake (ventilation) air velocities on the flow patterns of diesel particulate matter (DPM) generated by a man-riding vehicle operating in a straight rectangular cross section tunnel in an underground coal mine. The simulation results are validated against an earlier experimental study. At a sampling station 10 m downstream of the vehicle, the DPM concentration was seen to decrease rapidly with increasing intake air velocity. For air velocities of 0.5 m/s, 1 m/s, 2 m/s and 3 m/s, the DPM concentration was estimated to be 233 µg/m3, 131 µg/m3, 116 µg/m3 and 1 µg/m3 respectively. At 10 m downstream of the vehicle, if the intake air velocity is reduced from a base value of 1.26 m/s by 40% and 60% of the base value, the average DPM concentration increased to 58% and 123% respectively. If the intake air velocity is increased by 58% and 98% of the base case value, the average DPM concentration decreased to 44% and 78% respectively.

The research results of the spraying technical factors' impact on ground and air drift, and the deposit on the treetop in cherry orchards, are presented in the paper. Two different spraying systems (classical and sensory system) are investigated, Agromehanika AGP 200 ENU sprayer being used. The research is conducted according to ISO standard 22866 (Plant Protection Equipment - Drift Measurement Methods in Field Conditions). The impact of spraying norm as factor A (A1 – 250 l/ha; A2 – 200 l/ha); the nozzle type as factor B (B1 – Lechler TR 8002 C; B2 – Lechler ITR 8002 C) and the fan air velocity as factor C (C1 – 18 m/s; C2 – 12 m/s) are examined by the variance analysis. To spray and evaluate the drift, Tartazine organic dye solution with 4% concentration is used. The filter papers, used as collectors, according to the specified ISO standard, are placed directly in the spraying zone. The sampled filter papers are washed out with 10 ml of deionised water under laboratory conditions. After washing, the colour intensity, i.e., the solution wave-length, is read by a spectrophotometer (Varian Cary 50 UV-Visible). Different drift intensity (ground and air drift) and treetop deposits are realized by the usage of various treatments of technical spraying factors and various spraying systems. Unlike the ground and air drifts, the deposit within the treetop does not show statistically significant change by using a sensory spraying system, i.e. by using a selective application.

A pneumatic fertilization distributor used for fertilizing in a fertilizer applicator is a key component of the applicator. The parameters of a pneumatic fertilization distributor affect the uniformity and accuracy of the fertilization of a fertilizer applicator. To obtain the optimal design parameters of a pneumatic fertilization distributor, a fluidstructure coupling simulation test and a bench test were carried out in the Intelligent Agricultural Machinery Laboratory of the Nanjing Institute of Agricultural Mechanization from March 2021 to July 2022. The curvature–diameter ratios of the elbow, bellow length, and air velocity were selected as the experimental factors, and the variation coefficient of the fertilizer discharge at each discharge outlet within 0.5–3 s was selected as the experimental index. A five-level quadratic regression orthogonal rotation combined test was carried out. The results showed that: (1) all three factors had a significant impact on the uniformity of the fertilizer discharge. The reasonable ranges of the curvature–diameter ratio, bellow length, and air velocity were 0.5–1.5, 350–550 mm, and 25–35 m/s, respectively. (2) The order of the influence of the three factors on the uniformity of the fertilizer discharge in descending order was as follows: the curvature–diameter ratio of the elbow, the bellow length, and the air velocity. When the bellow length was 460 mm, the curvature–diameter ratio was 0.6, and the inlet air velocity was 28 m/s. The uniformity of the fertilizer discharge was optimal. A pneumatic conveying system was redesigned according to the optimal parameters, and a bench test was carried out. The results showed that at different speeds, the coefficient of variation of each row’s displacement was not greater than 5%, and the simulation test results were consistent with the bench test results.

This study uses a simplified two-dimensional time-dependent computational fluid dynamic (CFD) model to study the influence of wall shelf configuration and outtake honeycomb inclination angle on the performance of the air curtain in an open-type semi-vertical refrigerated display cabinet. Numerical simulation results show that changing the angle, along with changing the shelf configuration, can reduce the temperature of the intake air grille and improve the warm/cold air ratio. The average temperature of the simulated food products decreased by 1.2 °C compared to the unmodified display cabinet and began to meet the requirements of the temperature category 3M0. The proposed CFD model was validated by the experimental results. The simulation results obtained are important for cabinet design to improve product storage quality and reduce energy consumption.

Watermelon is a valuable source of nutrients and antioxidants that are beneficial for human health, but it is a seasonal and easily perishable fruit. Appropriate drying conditions should be considered to maintain the quality and nutritional attributes of watermelons after hot-air drying. This study aimed to investigate the effect of drying temperature and air velocity on some quality characteristics by response surface methodology. The drying trials were performed at temperatures of 55, 65, and 75 °C and air velocity of 1, 1.5, and 2 m/s employing a face-centered composite design. Some physical (a* value and browning index) and chemical (total polyphenols, the ferric reducing/antioxidant power, total anthocyanin, ascorbic acid, sucrose, total sugar, lycopene, total carotenoid, 5-HMF, and non-enzymatic browning) properties of dried watermelons were determined. The results indicated that the effect of drying temperature on the analyzed attributes was more significant than air velocity in general. Polynomial models with high R2 values were generated to predict the responses. The optimum drying conditions obtained (65.425 °C and 1.025 m/s) were experimentally validated. The proposed conditions provided better preservation of the quality characteristics (physical and chemical) studied for the commercialization of dried watermelons as a snack. [ABSTRACT FROM AUTHOR]

There are several environmental and ambient factors that can affect pig eliminative behaviour. The aim of this survey was to investigate factors related to the physical and ambient environment that have the strongest effects on pig and pen cleanliness and ammonia concentration. Data were collected from 87 pig farms and analysed using mixed (ammonia concentration) or generalized linear (pen and pig cleanliness) model in SAS. The pen was cleaner when pen partitions were open compared to closed (p = 0.010) and increased with increasing amount of litter (p = 0.002), using straw (p = 0.002) as rooting material. Pig cleanliness was higher when pen partitions in the eliminative area were open compared to closed (p = 0.007) and increased with increasing space per pig in the resting area (p < 0.001), with decreasing temperature (p < 0.001), and lowering of air velocity (p = 0.003). Other factors that increased cleanliness was using straw as rooting material (p = 0.028) and increasing amount of litter in the resting area (p = 0.002). Ammonia concentration was reduced with increasing floor space in the eliminative area (p < 0.001) and increasing amount of litter (p = 0.006). Our results pinpoint physical and ambient conditions affecting pen and pig cleanliness and air quality.

Measurements of air flow velocity are essential at every stage of the design, construction and operation of wind turbines. One of the basic measurement tools in this area is the tachometric anemometer, which is based on the simple physical phenomenon of the air kinetic energy exchange with a rotating measuring element. Tachometric anemometers have favorable operational features and good static metrological parameters. However, in the case of fast-changing flows, the measurement is burdened with a significant dynamic error, and the measured average value of the velocity is overestimated. This article presents the concept and results of pilot studies of a dynamic error correction method of tachometric anemometers. The correction consists of the precise measurement of the rotor’s rotational velocity and determination of the measured air velocity, taking into account the dynamics of the instrument. The developed method can be used in tachometric anemometers intended for laboratory, technical and industrial measurements in time-varying flows. One of the important application areas is the measurement of wind energy.

As a result of COVID-19, many office buildings around the world have downsized their employees, but the comfort parameters in the building had to be kept. The facilities operation rearranged the workstations to keep physical distance and placed plexiglass sheets on the desks for physical protection. A series of measurements have been carried out with workstation set-ups to examine the fresh air rate in the occupied zone. The effect of plexiglass sheets placed on the desks was also examined to see how it changes the airflow pattern in the occupied zone. As the sheets act as a barrier, the primary air does not reach the occupied zone, therefore, the fresh air rate is less. To modify the properties of the ceiling diffusers a new air-ventilation service element was developed. This attachment allows modifying the properties of the ceiling diffusers. Simulations were made at the relevant zones to validate the measurements. Based on design software, the fresh air ratio for a standard ceiling swirl diffuser is 2.46 v% (volume percentage). A numerical model was used to show the fresh air ratio with the system elements for the two different table arrangements, which were 18.3 v% and 21.4 v%, respectively.

Broiler chickens exposed to heat stress adapt to various behavioral changes to regulate their comfortable body temperature, which is critical to ensure their performance and welfare. Hence, assessing various behavioral responses in birds when they are subjected to environmental changes can be essential for assessing their welfare under heat-stressed conditions. This study aimed to evaluate the effect of two air velocity (AV) treatments on heavy broilers’ behavioral changes from 43 to 54 days under summer conditions. Two AV treatments (high and low) were applied in six poultry growth chambers with three chambers per treatment and 44 COBB broilers per chamber from 28 to 61 days in the summer of 2019. Three video cameras placed inside each chamber (2.44 m × 2.44 m × 2.44 m in dimension) were used to record the behavior of different undisturbed birds, such as feeding, drinking, resting, standing, walking, panting, etc. The results indicate that the number of chickens feeding, drinking, standing, walking, sitting, wing flapping, and leg stretching changed under AV treatments. High AV increased the number of chickens feeding, standing, and walking. Moreover, a two-way interaction with age and the time of day can affect drinking and panting. This study provides insights into heavy broilers’ behavioral changes under heat-stressed conditions and AV treatments, which will help guide management practices to improve birds’ performance and welfare under commercial conditions in the future.

In order to clarify the influence of air velocity on the atomization effect of shearer external spray and optimize dust suppression performance, the dust removal experiment was carried out by utilizing the self-designed external spray experiment platform. The effect of three kinds of air velocity on the atomization effect of main spray parameters was investigated to clarify the influence of air velocity on the atomization effect of shearer external spray and optimize dust suppression performance. The results showed that the influence of air velocity on droplet size and distribution width of the droplet size was slightly less than the spray pressure. The average diameter of the droplet was 54.211 lm, and the particle size distribution of the droplet was more uniform and concentrated when air velocity was 2 m/s, the pressure was 5 MPa and nozzle diameter was 1.0 mm. When the air velocity was less than 2 m/s and the spray pressure was 3-5MPa, the atomization effect was better by using 1.0 or 1.2mm diameter nozzle. Through on-site applications and optimization, the leeward total dust removal efficiency of the shearer can reach 79.43%, and the maximum increase range can reach 18.51 percentage points. The respiratory dust removal efficiency of the shearer can reach 87.45%, and the maximum increase range can reach 11.87 percentage points. [ABSTRACT FROM AUTHOR]

Air supply to free-surface water flows in tunnels is a key safety issue for high-head dams. The present study analyses the effects of approach water velocity and area residual of tunnel cross-section on air demand, using the volume of fluid (VOF) method in combination with the k–ε turbulence model. For a tunnel area residual less than 0.4, the attenuation of air velocity above the free-surface water flow decreases with an increase in water velocity. For larger area residuals, the air velocity distributions remain unchanged. The maximum ratio of mean air velocity to water velocity is obtained if the relative area residual is equal to 0.4. A relationship for the mean air velocity above the water flow is suggested. Without considering the flow aeration condition, the numerical simulations reproduce the air demand in the tunnel flow normally with an average error of ±25%. These results provide reference for air ventilation design of flood discharge tunnels. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A heated room is numerically analyzed to study thermal comfort. Cold air flowing in from the inlet gets heated by a heat source (placed just below the inlet), before being distributed throughout the room. The presence of the heat source and a high Rayleigh number causes the flow of air to be buoyant and turbulent. Two RANS based turbulence models, RNG k-ε and k-ε SST turbulence models are used to model turbulence and the Discrete Ordinate (DO) radiation model is used to model radiation heat transfer between different surfaces in the room. In order to account for buoyant air movement, air is approximated as a Boussinesq fluid. Parameters that affect comfort such as comfort temperature, operative temperature, turbulence intensity, velocity and the temperature difference between the head and ankle level are investigated. It is found that the comfort temperature and operative temperature predicted in this study have similar profiles irrespective of the turbulence models. Predicted values of turbulence intensity and velocity were low, which shows a low risk of drought in the occupied zone. The two RANS models give results similar to earlier studies that were performed with different turbulence and radiation models, proving their robustness and viability for a variety of flow problems. [ABSTRACT FROM AUTHOR]

Copyright of Annals of Warsaw University of Life Sciences - SGGW, Forestry & Wood Technology is the property of Wydawnictwo SGGW and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heat stress is a key factor affecting the productions of the animals. In laying birds, it could cause loss of body weight and high mortality. To this end, a study was carried out in a naturally ventilated, tier-caged layer house to evaluate the environmental parameters and the heat stress index within the building during hot weather period. Throughout the study, the environmental parameters (air temperature, relative humidity and air velocity), inside and outside the experimental building were measured and recorded. The heat stress index using the temperature-humidity index (THI) was also estimated. The results of the study indicated that laying birds in this study were most of their lifetime subjected to hot conditions which could have a significant effect on their performances. It was also found out that the air velocity within the building was very low (0.07 ms-1 to 0.58 ms1) which could not provide a cool environment for the birds. The heat stress index (THI) inside laying bird building was found to be mostly influenced by high relative humidity compared to ambient temperature. Therefore, it would be appropriate if the airflow distribution inside the poultry building, in this study, could be evaluated using computational fluid dynamics to understand the velocity profile within the building. This could assist engineers to redesign the building and make it appropriate for laying birds in the humid tropical climate.

Building envelope not only provides us the protection from outside environment but also provides the necessary thermal comfort required for anyone residing inside it. It is observed that the natural cooling arrangements provided in the ancient buildings have a great influence on the thermal comfort inside the buildings. This type of arrangement of thermal comfort is not considered while designing new structures. So,the energy consumption in modern structure is more for the same thermal comfort as in ancientstructures. Inside humidity,room temperature, mean surface temperatures, air variation ratio and lighting are some factors affecting thermal comfort. The materials such as cement and steel used in modern constructions are highly durable but not energy efficient. Hencenecessary balance must therefore be achieved between energy efficiency and durability of modern buildings. Against this background, the paper presentsacomparison of the thermal comfort inside the Tomb of Mohammad Ghaus heritage buildingand a modern style dwelling estimatedaround 10 yearsold. The average inside temperature of modern and heritage building was 32.65°C and 26.96°Crespectivelywhile the average outside temperature during observation period is 29.96°C. The average inside relative humidity of modern and heritage building was 61.73% and 68.93% respectively. As the heritage building was found cooler than the modern building, the study suggests thatthe cooling arrangement provided in the ancient buildings is imitable and beneficial tobe incorporated in modern buildings.

Heavy broilers exposed to hot summer conditions experience fluctuations in surface temperatures due to heat stress, which leads to decreased performance. Maintaining a bird’s homeostasis depends on several environmental factors (temperature, relative humidity, and air velocity). It is important to understand the responses of birds to environmental factors and the amount of heat loss to the surrounding environment to create thermal comfort for the heavy broilers for improved performances and welfare. This study investigates the variation in surface temperatures of heavy broilers under high and low air velocity treatments. Daytime, age and bird location’s effect on the surface temperature variation was also examined. The experiment was carried out in the poultry engineering laboratory of North Carolina State University during summers of 2017, 2018, and 2019 as a part of a comprehensive study on the effectiveness of wind chill application to mitigate heat stress on heavy broilers. This live broiler heat stress experiment was conducted under two dynamic air velocity treatments (high and low) with three chambers per treatment and 44 birds per chamber. Surface temperatures of the birds were recorded periodically through the experimental treatment cycles (flocks, 35–61 d) with infrared thermography in the morning, noon, evening, and nighttime. The overall mean surface temperature of the broilers under two treatments was found to be 35.89 ± 2.37 °C. The variation in surface temperature happened due to air temperature, thermal index, air velocity, bird’s age, daytime, and position of birds inside the experimental chambers. The surface temperatures were found lower under high air velocity treatment and higher under low air velocity treatment. During the afternoon time, the broilers’ surface temperatures were higher than other times of the day. It was also found that the birds’ surface temperature increased with age and temperature humidity indices. Based upon the experimental data of five flocks, a simple linear regression model was developed to predict surface temperature from the birds’ age, thermal indices, and air velocity. It will help assess heavy broilers’ thermal comfort under heat stress, which is essential to provide a comfortable environment for them.

The article is devoted to the air distribution in a room by swirl and laying air jets. Dynamic parameters of air flow that is created due to swirl and laying air jets at their leakage in a room has been determined. The mathematical model of air supply with swirl and laying air jets in the industrial rooms is improved. Simulation of air flow is performed due to CFD FLUENT (Ansys FLUENT). Solution of the equation by using k-ε model of turbulence is presented. Dynamic parameters of air flow that is created due to swirl and laying air jets at their leakage at variable regime and creation of dynamic microclimate in a room has been determined. Results of experimental investigations of air supply into the room by air distribution device which creates swirl air jets for creation more intensive turbulence air flow in the room are presented. The results of theoretical researches of influence of dynamic microclimate to the human organism are presented.

The perforated solar collector technology is a highly potential solution to take advantage of renewable energy in tropical countries such as Indonesia. This technology can be applied as a simple technology for drying of agricultural products. This study aims to determine the rate of the decreased moisture content of gaharu leafs. In this study, the perforated solar collector equipped with four ribs was used. The efficiency evaluation of perforated solar collector plate was conducted in Wind Tunnel-Rig, Basic phenomenon Laboratory of Mechanical Engineering Department, Sriwijaya University. The dimension of the plate is 850 mm × 300 mm × 1.5 mm, which has 1018 holes with 2.5 mm in diameter. The results show that the drying rate for achieving the 10% moisture content of the gaharu leafs, can be reached in 2–3 days. This condition occurs when the weather is sunny, or not cloudy and rainy. In other condition, when the sunshine with an average solar irradiation on the surface is greater than or equal 500 W/m2. The efficiency tests of the perforated aluminum plate solar collector using wind velocity as input parameter show that the blackened plate resulted in better performance (12,83%) than the colorless one in (6,36%). ABSTRAK Teknologi kolektor surya berlubang ini merupakan salah satu solusi untuk dapat memanfaatkan energi baru terbarukan yang peluangnya sangat besar untuk dikembangkan di negara beriklim tropis seperti negara Indonesia. Teknologi ini dapat digunakan sebagai teknologi tepat guna untuk mengeringkan produk-produk pertanian. Tujuan penelitian ini adalah untuk menentukan laju penurunan kadar air daun gaharu. Dalam pengujian pengeringan ini digunakan kolektor surya berlubang bersayap empat. Evaluasi efisiensi pelat kolektor surya berlubang dilakukan di Wind Tunnel Laboratorium Fenomena Dasar, Jurusan Teknik Mesin, Universitas Sriwijaya. Dimensi dari pelat kolektor surya berlubang adalah 850 mm x 300 mm x 1,5 mm, dengan jumlah lubang 1.018 buah yang berdiameter 2,5 mm. Hasil penelitian menunjukkan bahwa laju pengeringan daun gaharu untuk mencapai kadar air 10 % dapat dihasilkan dalam 2 ¸ 3 hari. Kondisi ini terjadi bila cuaca cerah, tidak hujan dan tidak berawan. Dalam kondisi lain, ketika matahari bersinar dengan radiasi matahari rata-rata yang mencapai permukaan lebih besar atau sama dengan 500 W/m2. Pengujian efisiensi kolektor surya pelat alumunium berlubang dengan parameter kecepatan udara, menunjukkan bahwa pelat berwarna hitam menghasilkan performansi yang lebih baik (12,83%) dibandingkan dengan pelat tanpa warna (6,36%).

This research studied microclimate and evapotranspiration (ET) of pepper in high tunnel screenhouses and greenhouses. A study was carried out during three consecutive seasons, 2015–2016 (Season I), 2016–2017 (Season II) and 2017–2018 (Season III), in two high-tunnels. One was covered by a plastic sheet (greenhouse) and the other by a porous screen (17 mesh insect net; screenhouse). Other than the covers, the structures were identical. In both houses, microclimate variables were measured simultaneously above the canopy. Evapotranspiration was estimated using six different variations of the Penman–Monteith model. Plant transpiration was measured by the heat pulse technique. Measured transpiration was compared with model estimates of ET to identify the model in best agreement with measurements. Linear regressions between internal and external climatic conditions resulted in R2 values between 0.003 (greenhouse temperature) and 0.99 (greenhouse global radiation). Generally, higher R2 values were obtained for the screenhouse because internal microclimate interacted with the outside more than in the greenhouse. Mean daily evapotranspiration estimated by the six Penman–Monteith models tested was 1.61–4.23 and 1.42–4.43 mm day−1 for the greenhouse and screenhouse, respectively. Mean daily ratio between ET models and transpiration measurements varied between 0.81 and 2.01 with a mean value of 1.20 ± 0.34 (where ± is standard deviation). The comparison between transpiration measurements and the PM models showed that in most cases models based on internal climatic conditions were in better agreement with measurements than those based on the external conditions. • Pepper transpiration and microclimate were measured in high tunnels. • Various models estimated ET in a greenhouse and a screenhouse. • Screenhouse microclimate interacted with the outside more than the greenhouse did. • Models using internal conditions were better than those using external climate. [ABSTRACT FROM AUTHOR]

Temperature and temperature consistency have an important effect on the effective performance and thermal safety of lithium-ion batteries. Huge temperature inconsistency can lead to the behavior of overcharge and overdischarge so that it improves the risk of fire and thermal runaway. Temperature rise and heat generation rate during discharging under adiabatic condition are measured by experiments. Based on the conclusion and data obtained by experiments, the finite element model of traditional and optimized parallel air-cooled structure are built by COMSOL Multiphysics 5.3a®. Meanwhile, the problem of flow inhomogeneity in parallel air-cooled structure and the cooling performance of optimized design are researched and discussed. Obvious temperature inconsistency is observed inside the battery module with a traditional cooling structure. Adding a fan on the bottom of module contributes to decay the maximum temperature and improve the temperature consistency effectively. The average temperature difference is maintained at about 1.4°C when the velocity of inlet air exceeds 7 m s−1, which is merely half of that in traditional structure. Temperature difference inside battery module is smaller with the rise of inlet air velocity. Moreover, temperature consistency could be improved by increasing the radius of fan or setting the outlet on the right above of battery module. [ABSTRACT FROM AUTHOR]

Diversity in living standards and population growth leads to increased global energy consumption. Human comfort always plays a vital role in using different means to reduce the effects of weather conditions. The building sector captures approximately 40% of the global energy and it is most commonly used for cooling and for heating of the space occupied due to the use of appliances such as room heaters or air coolers, air conditioners, etc. The use of these appliances contributes significantly to global warming, which is a very serious environmental problem. Passive energy sources are used widely to reduce the consumption of energy due to heating and cooling of the building. Earth air pipe heat exchanger is one of the passive cooling/heating technology used for the indoor thermal comfort of the occupants. In this review article, various discussion has been done on the use of passive energy explained by the earth air pipe heat exchanger and various investigations conducted by authors under different conditions and parameters like air velocity, pipe depth, pipe length, etc. that the thermal conductivity of the soil is the key point to the efficient operation of the earth air pipe heat exchanger system and it is also necessary to maintain the thermal conductivity of the soil in the vicinity of the pipe in order to achieve better performance in operation. [ABSTRACT FROM AUTHOR]

Copyright of Tobacco Science & Technology is the property of Tobacco Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Ciencia Animal - RECIA is the property of Revista Colombiana de Ciencia Animal - RECIA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To solve the problems that the borehole depth is shallow and the drilling efficiency is low during the gas drainage drilling in soft coal seam with current cuttings removal method, a new technology of reverse circulation pneumatic cuttings removal is proposed. The working principle of reverse circulation pneumatic cuttings removal is analyzed, and the kinetic equation of cuttings in the inner hole of the drill pipe is established. Through experiments, the pressure drop in the drill pipe is measured to reveal the effects of air velocity, cuttings mass flow rate, and cuttings particle size on the pressure drop in inner hole of the drill pipe. When the cuttings mass flow rate is constant, the pressure drop increases with the increase in air velocity. When the air velocity is constant, the pressure drop increases with the increase in cuttings mass flow rate. At low air velocity, the pressure drop of cuttings is primary. As the air velocity increases, the pressure drop ratio of cuttings decreases. Under the same conditions, the order of pressure drop with different particle size cuttings is coarse cuttings > medium cuttings > fine cuttings. Empirical equation of pressure drop coefficient of cuttings is established, which is in good agreement with the actual data. [ABSTRACT FROM AUTHOR]

In this paper the complete approach is introduced for study of Ballast flying in wind tunnel considering track vibrations and aerodynamic loads. The air velocity profile under high speed train with speed of 300 km/h is introduced using an analytical approach and the intensity of under train wind is defined. About 50 kg of Iranian high speed railway ballast is adopted by random sampling and classified according to mass and aerodynamic shape. The critical velocities of ballast moving are measured by wind tunnel for all classification to obtain the ballast flying probability factor (BFPF) at two modes of with and without track vibration. Also, the conventional ballast flying risk mitigation methods in wind tunnel are reviewed and a new strategy for ballast flying risk mitigation is introduced and tested, based on the design of track surface by a special sieved group of ballasts with minimum flying probability factor. Results show that the BFPF increases in presence of vibration and the minimum value of BFPF is occurred at mass range of 150-200 g. It's stated that application of this group on the track surface may prevent from ballast flying due to passing of train with maximum speeds of 300 km/h. [ABSTRACT FROM AUTHOR]

• The optimal control of environmental conditions is an effective way for improving plant growth, quality, and input resources use efficiency. • Light is the main source of energy required for photosynthesis and many other physiological processes related to plant growth. • Light quality influences plant growth and development more than light intensity and photoperiod. • Light spectrum for plant response ranges from the UV (280–400 nm) to the far-red (700–800 nm) regions. • More studies are still needed, taking into account integrative environmental control, input resources efficiency, and economic analysis. Lettuce is one of the most popular leafy vegetables produced in controlled environments with artificial lighting (CEALs). Optimal control of environmental conditions can be used to facilitate the improvement of lettuce plant growth and light use efficiency. This article reviews and discusses the effects of light, air velocity, temperature, relative air humidity, and CO 2 concentration on the growth and development of lettuce plants in a CEAL. A review of previous studies revealed that light intensity in the range between 200–250 µmol m−2 s−1 with a photoperiod of 16–18 h using red and blue LEDs, with a ratio between 5 and20% for the blue light are optimal to improve lettuce plant growth and light use efficiency. The optimal light quality can also be achieved by using supplemental white or green LEDs, far-red light, and UV-A radiation. Air velocity in the range between 0.3 and 0.7 m s−1 enhances the photosynthetic rate, transpiration rate, and gas diffusion through the boundary layer of the leaf and prevents the occurrence of tipburn. The air temperature of 22–25 °C during the light periods was reported as optimal to enhance CO 2 uptake and consequently improve lettuce growth. Relative air humidity in the range between 70 and 80% promotes vegetative growth and reduces water stress by causing the stomata to close. High CO 2 concentrations increased photosynthetic rate but also decreased CO 2 utilization efficiency. Therefore, CO 2 concentration in the range between 1000 and 1500 µmol mol−1 is optimal for high growth rate, productivity, and CO 2 utilization efficiency. Most of the previous studies have focused on the effect of light intensity, quality, and duration on the growth and development of lettuce plants under artificial light, with limited information about the interactions of all environmental conditions. This review will be useful for growers, researchers, and designers in the field of plant production in CEALs. [ABSTRACT FROM AUTHOR]

• A 2D-PIV technique was used to study the airflow in a closed display cabinet. • Zone of air recirculation in the closed configuration was identified. • Ambient air infiltration through the door gaps was quantified. • 2D-CFD model allows the study of influence of flow pattern on temperature distribution. Air velocity measurements were carried out using the Particle Image Velocimetry (PIV) technique in a display cabinet under two configurations: closed and open doors. Two conditions (refrigeration system turned "on" and turned "off") were studied in the closed configuration. The airflow pattern was almost the same for both conditions. The air curtain was quite stable. In the upper part of the cabinet, air recirculation occurred, and this phenomenon induces external air infiltration through the door gaps. The air curtain in the open configuration (refrigeration system turned "off") was less stable than the closed configuration. Large unsteady eddies developed in the mixing layers, thereby promoting greater external air infiltration. A two-dimensional computational fluid dynamic (2D-CFD) model was developed and showed the ability to reproduce the main flow phenomena observed in the experiment. The trend of predicted product temperature profile was also in agreement with the experimental values, despite slight underestimation. [ABSTRACT FROM AUTHOR]

Orange is an important commercial crop, which is being exported from Egypt. Citrus packhouses in Egypt receive, ship excessive quantity to overseas during glut. Since most of the facilities have limited refrigeration capacity to deal with this situation, one approach is to apply pre-cooling on the citrus plastic bin. These bins have more vented area and therefore represent less air resistance to refrigerated air requiring shorter time cycles. Hence, the objective of the current study was to investigate the effect of the cooling rate of the Navel orange as a function of fruit size, air direction (vertical forced and vertical induced) and air velocity, on weight loss and electrolyte leakage. A cold store with an air temperature of 4 °C was used to host the supplementary experimental set-up and provide the supply air temperature. The fruit temperature for different treatments was monitored and recorded at equal time intervals (1 min). The seven-eighths cooling times ranged from 217 to 76 min. The forced-air pre-cooling with the highest air velocity of 1 m s−1 resulted in the shortest significant cooling time in all fruit sizes. The forced air cooling at the three rates did not significantly affect either the fruit weight loss percentage or the electrolyte leakage of the three fruit sizes of navel orange after 2 weeks at 5 ± 1 °C + 1 week at room temperature. The indices presented in the present work could be used to estimate cooling time for another pre-cooling process for batch types of citrus under similar circumstances. [ABSTRACT FROM AUTHOR]