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The scientific task of the nozzle scheme uses for formation of an air cushion by using the energy of a jet of air supplied under pressure, simultaneously to form an air cushion, as well as to create the driving force of a load-bearing web, was formulated and the main idea of the work was defined. The optimal option to significantly increase the productivity and length of special types of conveyors is to use the energy of a jet of air supplied under pressure simultaneously as an air cushion and as the driving force of the load-carrying body, which makes it possible to sharply reduce the coefficient of resistance to movement of the load-carrying body and improve its operating conditions. Supporting the load-carrying body with an air cushion allows to increase the speed of movement to 8 to 9 m/s and more, increase the reliability and safety of conveyor operation, and protect the environment. [ABSTRACT FROM AUTHOR]

This study used a graphene far infrared dryer to experimentally evaluate the two varieties of corn (ZD88 and RP909) at three varying temperatures (35, 45, and 55 °C) to analyze the drying process. The experimental finding showed that ZD88 observed a minimum energy consumption of 2.93 kWh at 55 °C. The ZD88 at 35 °C did not show any effect on the structure on the surface of the corn grains with a higher RC of 43.85%. The RP909 showed the starch granules formed an amorphous granular structure on the surface with a lower RC of 37.45% at 55 °C. The color parameter values showed an L* and b* decrease, while the a* values increased. ZD88 and RP909 observed an A-type peak pattern crystal structure. Therefore, this innovative graphene far infrared drying system could be a promising solution to enhance food industrial applications and improve corn characteristics. [ABSTRACT FROM AUTHOR]

Heating in the winter is one of the human activities that consumes the most energy, thereby affecting the environment and leaving a carbon footprint. An increase in heating efficiency results in a reduction in the energy demand of the process and environmental protection. This contribution aimed to determine and experimentally verify the possibility of obtaining and effectively using the heat from the chimney of a gas boiler generated during the heating of a family house. For this purpose, we used a simple heat exchanger and measured the relevant temperatures on an exchange unit for almost five months during the heating season. The air temperatures measured at the inlet and outlet of the exchanger unit together with the outside temperatures were statistically analyzed to determine the effect of using the exchanger unit to obtain additional heat that could be used for other purposes. In addition, this study investigated whether there was a statistically significant difference in the temperature of the air entering the heating system with different outdoor temperature values. In the discussion, these hypotheses are either confirmed or disproved. Finally, the effectiveness of the current household heating system is evaluated. [ABSTRACT FROM AUTHOR]

In agricultural greenhouses, effective heating systems are essential for maintaining proper temperature control and air circulation during the winter. This study delves into the analysis of heat exchange through natural convection within heated greenhouses, with a particular emphasis on the impact of bottom heating. Two distinct types: mono‐chapel and bi‐chapel, each featuring triangular or spherical roofs are examined. To capture the variable roof shapes, we employ a change‐of‐variable method, and the numerical solutions are obtained using the finite volume method. The results show that heat transfer is enhanced by increasing the Rayleigh number. This improvement differs according to the shape of the roof. Heat transfer decreases by about 5% for the spherical mono‐chapel case compared to the triangular case for Ra = 103. For Ra = 105, the monospherical case favors heat transfer, with an increase of 0.35% compared to the triangular case. In the case of bi‐chapel roof, heat transfer is greater with a triangular roof for Ra = 103, showing an increase of 6.4% compared to the spherical case. This study not only sheds light on the fundamental aspects of heat transfer in greenhouses but also provides valuable insights for optimizing greenhouse design based on specific roof configurations and heating conditions. [ABSTRACT FROM AUTHOR]

Recycling salt and water from saline wastewater is crucial for environmental preservation, resource conservation, and social economy sustainability. The heat pump air circulation evaporating separation (HP-ACES) system for saline wastewater treatment is proposed. Nevertheless, it is discovered that the system evaporation efficiency (SEE) is low and solid crystalline salt does not precipitate during the experiment. Therefore, an established and validated mathematical model of the HP-ACES system is provided and the average relative errors of the system evaporation rate (SER) and SEE are 5.3 % and 7 %, respectively. The theoretical analysis of the non-optimized system indicates that the main cause of the low SEE of the HP-ACES system during the test is incorrect cooling water flow. Hence, the system optimization scheme is presented and the comparison of the HP-ACES system's performances before and after optimization is conducted. Results demonstrate that the SEE of the optimized HP-ACES system has been greatly improved (optimized system: 0.62–2.46 kg/kWh, non-optimized system: 0.77–0.91 kg/kWh). Additionally, there is almost no change in the yield and composition of the solid crystalline salt when the inlet air temperature of spray separation tower is above 90 °C.

The scientific task of the nozzle scheme uses for formation of an air cushion by using the energy of a jet of air supplied under pressure, simultaneously to form an air cushion, as well as to create the driving force of a load-bearing web, was formulated and the main idea of the work was defined. The optimal option to significantly increase the productivity and length of special types of conveyors is to use the energy of a jet of air supplied under pressure simultaneously as an air cushion and as the driving force of the load-carrying body, which makes it possible to sharply reduce the coefficient of resistance to movement of the load-carrying body and improve its operating conditions. Supporting the load-carrying body with an air cushion allows to increase the speed of movement to 8 to 9 m/s and more, increase the reliability and safety of conveyor operation, and protect the environment.

There is a gradual increase in the discharge of saline wastewater which is harmful to the environment and human health. A novel heat pump air circulation evaporating separation (HP-ACES) system for saline wastewater treatment is proposed and experimentally investigated. The results show that the system evaporation efficiency (SEE) initially decreases before increasing with the expansion valve opening at different refrigerant charges. However, the SER increases by 0.67 kg/h at 1.21 kg refrigerant charge while they descend and then rise at 1.53 and 1.86 kg refrigerant charges. Noted that the effects of expansion valve opening on the SER and SEE are lessened with refrigerant charge. Moreover, there exist the optimal values of total air flow and air flow proportion of packing concentration tower at which the SER and SEE peak, and both of the solution concentration and cooling water flow negatively affect the SER and SEE. Besides, compared with similar evaporating separation systems, the HP-ACES system has higher energy efficiency for treating high saline wastewater and the SEE ranges from 0.86 to 1.64 kg/kWh (5–25 % CaCl2 solution). However, the SEE is low, and it is necessary to reveal the cause and propose the optimization schemes in the future.

Heating in the winter is one of the human activities that consumes the most energy, thereby affecting the environment and leaving a carbon footprint. An increase in heating efficiency results in a reduction in the energy demand of the process and environmental protection. This contribution aimed to determine and experimentally verify the possibility of obtaining and effectively using the heat from the chimney of a gas boiler generated during the heating of a family house. For this purpose, we used a simple heat exchanger and measured the relevant temperatures on an exchange unit for almost five months during the heating season. The air temperatures measured at the inlet and outlet of the exchanger unit together with the outside temperatures were statistically analyzed to determine the effect of using the exchanger unit to obtain additional heat that could be used for other purposes. In addition, this study investigated whether there was a statistically significant difference in the temperature of the air entering the heating system with different outdoor temperature values. In the discussion, these hypotheses are either confirmed or disproved. Finally, the effectiveness of the current household heating system is evaluated.

In this study, we analyze the performance of ventilation modules to improve air quality in educational facilities. Using (CFD), we examine the flow design variables of a window-mounted ventilation module. Using computational analysis, we analyze various flow design characteristics of window-mounted ventilation modules and review optimal conditions. First, we measure the carbon dioxide concentration in the classroom and use CFD to analyze the internal air characteristics according to the ventilation module's inflow speed, inflow angle, and indoor temperature conditions. According to classroom air quality management standards, the concentration of carbon dioxide must be managed below 1000 ppm. When the ventilation module's inflow velocity was 2.0 m/s, a carbon dioxide concentration of less than 1000 ppm was measured in the classroom. Additionally, an air filter was selected to prevent the inflow of external fine dust through the ventilation module. The suitability of HEPA H14 was reviewed to design the weight concentration of fine dust flowing from the ventilation module to be less than 50 μg/m3. Through research, flow design conditions for a window-mounted ventilation module were presented to reduce carbon dioxide concentration inside the classroom. The analysis of the ventilation system flow characteristics proposed in this study derived primary data for improving the classroom ventilation system. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office 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.)

The climatic conditions Switzerland are unfavourable for cultivating pineapple plants. This is realised by pineapple plants requiring tropical temperatures to thrive and produce healthy fruits. In the agricultural sphere, pineapple plants can be propagated if the conditions for cultivation are favourable. However, in Switzerland, the cold climate has made the cultivation of Ananascomosus (L.) Merr. very difficult. It is only through human ingenuity that the cultivation of this plant has seen success in climates that would otherwise hinder the production of healthy pineapple fruits, like in Switzerland. This article will address many aspects regarding, and negating, to Ananascomosus (L.) Merr cultivation in Switzerland. [ABSTRACT FROM AUTHOR]

Copyright of Smart Rail Transit is the property of Smart Rail Transit Editorial Office 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.)

This study experimentally measured the ventilation efficiency in road vehicles. Two air circulation methods, air conditioning and opening windows, were considered and their ventilation efficiencies were measured for a sedan and a cutaway bus. The ventilation efficiencies have been evaluated by measuring the aerosol concentration parameter at different locations inside the vehicle. For both vehicles, any of the ventilation scenarios significantly increased the air exchange rate. The best performance was shown when all windows were open in a moving vehicle. As an illustration of using the obtained measurements, respiratory infection probability was calculated using the Wells-Riley model. Any of the ventilation cases significantly decreased the infection risk. The ventilation efficiency and infection probability were highly dependent on the air circulation method and vehicle type.

Aerosols carrying the virus inside enclosed spaces is an important mode of transmission for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as supported by growing evidence. Urban subways are one of the most frequented enclosed spaces. The subway is a utilitarian and low-cost transit system in modern society. However, studies are yet to demonstrate patterns of viral transmission in subway heating, ventilation, and air conditioning (HVAC) systems. To fill this gap, we performed a computational investigation of the airflow (and associated aerosol transmission) in an urban subway cabin equipped with an HVAC system. We employed a transport equation for aerosol concentration, which was added to the basic buoyant solver to resolve the aerosol transmission inside the subway cabin. This was achieved by considering the thermal, turbulent, and induced ventilation flow effects. Using the probability of encountering aerosols on sampling surfaces crossing the passenger breathing zones, we detected the highest infection risk zones inside the urban subway under different settings. We proposed a novel HVAC system that can impede aerosol spread, both vertically and horizontally, inside the cabin. In the conventional model, the maximum probability of encountering aerosols from the breathing of infected individuals near the fresh-air ducts was equal to 51.2%. This decreased to 3.5% in the proposed HVAC model. Overall, using the proposed HVAC system for urban subways led to a decrease in the mean value of the probability of encountering the aerosol by approximately 84% compared with that of the conventional system. [ABSTRACT FROM AUTHOR]

In this study, we analyze the performance of ventilation modules to improve air quality in educational facilities. Using (CFD), we examine the flow design variables of a window-mounted ventilation module. Using computational analysis, we analyze various flow design characteristics of window-mounted ventilation modules and review optimal conditions. First, we measure the carbon dioxide concentration in the classroom and use CFD to analyze the internal air characteristics according to the ventilation module’s inflow speed, inflow angle, and indoor temperature conditions. According to classroom air quality management standards, the concentration of carbon dioxide must be managed below 1000 ppm. When the ventilation module’s inflow velocity was 2.0 m/s, a carbon dioxide concentration of less than 1000 ppm was measured in the classroom. Additionally, an air filter was selected to prevent the inflow of external fine dust through the ventilation module. The suitability of HEPA H14 was reviewed to design the weight concentration of fine dust flowing from the ventilation module to be less than 50 μg/m3. Through research, flow design conditions for a window-mounted ventilation module were presented to reduce carbon dioxide concentration inside the classroom. The analysis of the ventilation system flow characteristics proposed in this study derived primary data for improving the classroom ventilation system.

Recent research on air pressure propagation through barometric caves has revealed various speleoclimatological processes, which cause a more complex relationship between surface air pressure changes and resulting pressure gradients between cave and surface air than previously assumed. So far, however, studies on barometric cave airflow have only been based on surface air pressure measurements. Thus, this study investigates and compares airflow at the openings of Wind Cave and Jewel Cave - two major barometric cave systems in South Dakota, USA - as a response to surface air pressure changes and air pressure gradients. Based on high-resolution long-term air pressure measurements from the surfaces and several locations inside the caves, as well as ultra-sonic airflow measurements at the openings, the analysis proves that for both caves, cave airflow velocity can be predicted more accurately by air pressure gradients than by previous surface air pressure changes. An inter-cave comparison also reveals substantial differences in cave airflow dynamics between Wind Cave and Jewel Cave, with the relevant period of surface air pressure variations for cave airflow velocity and the cave reaction times being significantly longer at Jewel Cave compared to Wind Cave. Therefore, the findings of this study demonstrate the effects of cave morphology on airflow and significantly contribute to a better understanding of the speleoclimatological mechanisms and dynamics of compensating airflow at the openings of barometric caves. [ABSTRACT FROM AUTHOR]

[Display omitted] • Increased ventilation had no positive effect on the water removal of sludge bio-drying. • Ventilation and pile temperature jointly determine the dehydration effect. • More than 30% of the water was removed during the non-ventilation process. • High ventilation obtained higher heat utilization efficiency with less energy input. • Air circulation achieved energy recovery but carried more water into the pile. Sewage sludge bio-drying technology has attracted considerable attention in recent years. In this study, we explored the water-heat balance under two ventilation strategies for the first time in bio-drying plants with circulated air, and examined the influence of air circulation on water removal and heat recovery. We want to obtain the relationships of pile temperature, ventilation, and water removal. Then, it provides support for optimizing the bio-drying process conditions and improving the efficiency through analysis of the water-heat relationship. In the low-ventilation and high-ventilation trials, water removed was mainly on Days 9–12 and 1–4, respectively. Ventilation and pile temperature jointly determine the water removed during the bio-drying process. Water balance indicated that more than 30% of the water was removed under the nonventilated process. More organic matter was degraded to maintain a higher pile temperature under low-ventilation than under high-ventilation, which also led to more radiation heat being lost. High-ventilation trial input less energy (3.36 MJ/kg water removed) but obtained a higher bio-drying index I (7.04) and heat utilization efficiency Q effic (94.1%). Heat balance showed that lower energy consumption by dry air (Q dryair) was obtained due to circulation air with high temperature. Circulation air also has a higher carried capacity of water vapor but carries more water into the pile due to higher humidity. [ABSTRACT FROM AUTHOR]

In mountain areas, air circulation plays a major role in the forming of the climate. This paper examines how it influences thermal stress in the northern Carpathians. The Niedźwiedź’s classification of air circulation was applied. Thermal stress was assessed by Universal Thermal Climate Index (UTCI). Daily meteorological and circulation data for the period 1986–2015 were used for 20 stations in Poland, Slovakia and Ukraine. Air circulation was found to have a significant impact on thermal stress. The highest UTCI values are observed at Ca+Ka (centre of the high and anticyclonic wedge or ridge of high pressure) and the lowest values at N+NE and W+NW circulation; at the Southward stations, UTCI is higher than in the Northward ones; thermoneutral days are more frequent on the southward than on the northward slopes; during N+NE, E+SE and W+NW circulation and for heat stress days, the greatest thermal privilege of the southward slopes is observed at E+SE, S+SW, Ca+Ka and Cc+Bc (centre of low and through of low pressure) types of circulation.

Aerosols carrying the virus inside enclosed spaces is an important mode of transmission for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as supported by growing evidence. Urban subways are one of the most frequented enclosed spaces. The subway is a utilitarian and low-cost transit system in modern society. However, studies are yet to demonstrate patterns of viral transmission in subway heating, ventilation, and air conditioning (HVAC) systems. To fill this gap, we performed a computational investigation of the airflow (and associated aerosol transmission) in an urban subway cabin equipped with an HVAC system. We employed a transport equation for aerosol concentration, which was added to the basic buoyant solver to resolve the aerosol transmission inside the subway cabin. This was achieved by considering the thermal, turbulent, and induced ventilation flow effects. Using the probability of encountering aerosols on sampling surfaces crossing the passenger breathing zones, we detected the highest infection risk zones inside the urban subway under different settings. We proposed a novel HVAC system that can impede aerosol spread, both vertically and horizontally, inside the cabin. In the conventional model, the maximum probability of encountering aerosols from the breathing of infected individuals near the fresh-air ducts was equal to 51.2%. This decreased to 3.5% in the proposed HVAC model. Overall, using the proposed HVAC system for urban subways led to a decrease in the mean value of the probability of encountering the aerosol by approximately 84% compared with that of the conventional system.

In this paper, we present a novel hypothesis as to what led humans in the Upper Paleolithic to penetrate and decorate deep, dark caves. Many of the depictions in these caves are located in halls or narrow passages deep in the interior, navigable only with artificial light. We simulated the effect of torches on oxygen concentrations in structures similar to Paleolithic decorated caves and showed that the oxygen quickly decreased to levels known to induce a state of hypoxia. Hypoxia increases the release of dopamine in the brain, resulting in hallucinations and out-of-body experiences. We discuss the significance of caves in indigenous world views and contend that entering these deep, dark environments was a conscious choice, motivated by an understanding of the transformative nature of an underground, oxygen-depleted space. The cave environment was conceived as both a liminal space and an ontological arena, allowing early humans to maintain their connectedness with the cosmos. It was not the decoration that rendered the caves significant; rather, the significance of the chosen caves was the reason for their decoration. [ABSTRACT FROM AUTHOR]

Mashrabiya had formed one of the most important elements of architecture specially civil architecture in Islamic heritage. As it is known as a successful architectural solution for climate nature because the shape of its configuration allows it to control sun rays and air currents and forming interior comfortable environment and also providing privacy specially in housing architecture. So Mashrabiya comes in our Islamic heritage with consistency with climate, privacy and culture considerations for the occupants of the interior environment additionally with Aesthetic considerations represented from its infinite design characterized with the elasticity of its formations. The Egyptian carpenter was one of the most handicrafts men who represented Mashrabiya arts with different designs and forms and he excelled at perfection at this kind of art and he represented it to the whole world in the form of beautiful wooden interfaces. Many International architects paid attention to this important architectural element and started taking inspiration from this concept to represent modern solutions for many architectural interface for public and private buildings and they turned this wooden local heritage element to elastic system for natural light responding to high technology and representing Contemporary aesthetic solutions taking its origins from Islamic heritage in consistency with modernization and Contemporary Technology.

This study developed a model that depicts the relationship, strength, and direction of the causality between the predictor variables (microclimatic variables) and a response variable (ambient temperature) interpreted for the physiologic equivalent temperature of an environment. Data collected were microclimatic variables which include air circulation, relative humidity, mean radiant and ambient temperatures over land cover materials namely tarmac, grass, soil and concrete at the premises of Federal University Wukari, Taraba state of Nigeria at a guided height of 1.1 m. The data was collected using physical measurements with respect to time of the day; morning (8:00 – 9:00 am), afternoon (1:00 – 2:00 pm) and evening (6:00 – 7:00 pm) and season of the year; dry (November – March) and wet (April – October) from April 2016 to March 2017. Comparative analysis of the data obtained from the survey and that of the developed model gave percentage variation range of 0.5 – 6.8%. However, in both cases there is an association between the microclimatic variables and the ambient temperature on each of the considered materials, season and measurement intervals. The ranges of the physiological equivalent temperature for different grades of thermal sensation and physiological stress on the land cover materials in this study was 30.2 – 43.3 °C which of intense thermal range. The physiologic equivalent temperature analysis for the land cover materials showed that there was variation in the mean radiant temperature with intense thermal effect in season and measurement intervals. This study depicted that combined use of several land cover materials in a particular area has impact on the mean radiant temperature. This necessitate that the design of the land surface environment should be with due consideration to the convective heat exchange between the outdoor workers and the ambient environment for their thermal comfort and occupational heat stress.

Introduction. For increasing the efficiency of natural ventilation systems, it is possible to use the thermal incentives - additional heating of the exhaust ventilation duct, which allows to expand temperature difference between ambient and exhaust air and to increase the circulation effect. This method enables stable air exchange in hot period, independently of the wind direction force. However, existing systems have several limitations of application in the high-rise apartment building in countries with a cold climate. The aim of the study is to develop a thermal inducement ventilation systems, suitable for typical residential apartment buildings in russian climate.Results. The article theoretically proves the disadvantages of existing thermal inducement ventilation systems. The article also presents the results of numerical modeling of natural convection currents in the high-rise apartment building. The dependence of outlet velocity on temperature difference for various heating methods is proved on the basis of the research.Conclusion. The results of the research illustrate the high level of the heating area location influence on free convection currents in vent duct.

Global water scarcity is one of the biggest human concerns in recent decades. Seawater desalination becomes the dominant way to access the new drinkable waters. The present study developed a heat pump-assisted humidification–dehumidification water desalination system. The designed system is equipped with a novel solar humidifier that works based on the free-flow solar water collectors. The effect of air flow rate and mode of the air circulation system on the performance of the designed system was experimentally investigated. The results reveal that raising the air flow rate improved water evaporation rate and the solar humidifier efficiency, while closing the air circuit led to a reduction in the evaporation rate. The maximum evaporation amount and water productivity were around 1.38 and 1 kg/h/m2 in the average solar irradiance of 877 W/m2. The closed-loop air circulation system resulted in a significantly higher effectiveness of dehumidification and produced higher desalinated water compared with the open-circuit mode. The lowest specific electrical energy consumption and the highest gained output ratio values of, respectively, 0.15 kWh/kg and 2.36 were observed at the air flow rate of 0.019 m3/s/m2 of solar humidifier when closing the air circulation system. [ABSTRACT FROM AUTHOR]

Copyright of Ars Longa is the property of Ars Longa 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.)

Chornohora is the highest mountain ridge in the Ukrainian Carpathians with 6 peaks of an altitude over 2,000 m above sea level (Hoverla is the highest peak, 2,061 m a.s.l). Its climate is explored less than other mountain ridges in Europe. The massif is a climatic barrier for air masses on NW-SE line. To describe the climate of this area data from the weather station at Pozhyzhevska alpine meadow for the years 1961–2010 were used. The seasonal and long-term variability of air temperature, atmospheric precipitation and snow cover were investigated on the background of air circulation types. The results show that general features of Chornohora climate depend both, on elevation above sea level and on air circulation. Lowest temperature is observed at N-NE circulation and highest precipitation – at western air inflow. Long-term changes of examined climate elements in Chornohora show significant increase in mean (0.13°/10 years) and minimum (0.22°C/10 years) air temperature as well as in snow cover depth and number of snowy days. [ABSTRACT FROM AUTHOR]

[Display omitted] • Demonstrate the blowout of different diffusion flames remotely by a moving air vortex ring. • The air vortex ring with less than 1% of the flame power is sufficient to cause blow-off. • The instant release of vortex core kinetic energy is defined as the main factor causing flame extinction. • Propose a Damköhler number criterion to identify blow-off limits for different fuels and burners. The blow-off is one of the typical flame extinction mechanisms, and such a principle has been widely used in firefighting when the water-based extinguisher is limited. This work explores the blow-off extinctions of different diffusion flames by air vortex ring. The vortex ring harnesses its kinetic energy within the fast-rotating vortex core, enabling the transmission of power over several meters to blow off a remote flame. The power required for vortex ring blow-off is found to be two to three orders of magnitude smaller than the power of the flame itself, demonstrating exceptional energy efficiency. It is observed that the poloidal flow (circulation) surrounding the vortex core can stretch the flame base to the critical state and then cause instantaneous extinction. To explain the vortex-induced blow-off limit, a critical Damköhler number that accounts for the competition between fuel gas flow and flame stretch was formulated. This work provides a fundamental understanding of the extinction mechanism by vortex ring, and it offers technical guidelines for using air as a flame extinguisher for remote firefighting within minimum energy input. [ABSTRACT FROM AUTHOR]

A greenhouse has one purpose: to provide and maintain the environment that will result in optimum crop production for maximum profit. This includes an environment for work efficiency as well as for crop growth. This publication is limited to describing equipment and methods used to control or maintain desirable temperature in a greenhouse during those periods when supplemental heat is required. There are many ways this can be accomplished from the standpoint of equipment used, type of fuel and construction used, and management practices followed. Because each operation usually has some unique characteristics, such as types of plants produced, level of desired production quality, type(s) of greenhouse(s) used, and management procedures followed, it is important that all of these factors be considered when selecting and installing a heating system. This 5-page fact sheet is a minor revision written by J. A. Watson, C. Gómez, D. E. Buffington, R. A. Bucklin, R. W. Henley, and D. B. McConnell, and published by the Department of Agricultural and Biological Engineering, November 2019. AE11/AE015: Heating Greenhouses (ufl.edu)

Hearths were constructed and used at Paleolithic cave and rockshelter sites in Africa, Europe and Asia as early as the late Lower Paleolithic period. The advantages of the use of fire have been widely researched for the last decades. However, only a few studies have focused on the possible negative impact of the use of fire within closed spaces, such as caves. One of the major negative fire products is smoke, which has an immediate, as well as long-term, effect on humans and may even prevent cave occupation after a short period. In this study we propose a basic air circulation model based on thermodynamics to represent smoke ventilation in caves. We employ this model to shed light on the relationship between smoke dispersal and cave structure, opening dimensions, hearth characteristics, and seasonal temperature fluctuations. We further show that hearth location was crucial in allowing humans to occupy prehistoric caves while using fire on a regular basis. We present preliminary insights from specific case studies, demonstrating the potential of understanding smoke ventilation in reconstructing the hearth season of use and location within the cave.

Indoor solar-heating systems that use ventilated roofs have drawn attention in recent years. The effectiveness and efficiency of such air-heating systems vary depending on the design and operation methods. In Japan, by introducing outside air into a ventilated roof cavity and circulating the air indoors, systems that simultaneously obtain ventilation, solar heating, and heat-storage effects have been actively developed. The conventional systems intake a large volume of outside air to increase the solar heat collection effect. However, there is a risk of heat loss and over-drying when a large amount of cold dry air during winter is introduced. In this paper, plans are presented for improving these solar heating and heat-storage effects by preventing over-drying using indoor air circulation via ventilated cavities in the roof and indoor wall. By comparing the results of the proposed system with those of the conventional system via numerical simulation, the heating load is found to be reduced by 50% or more by circulating indoor air to the ventilated roof and storing the heat in the indoor wall. Moreover, an increased relative humidity of approximately 10% was confirmed by reducing the intrusion of the outside air and keeping the moisture indoors.

This study describes a newly developed prosthetic leg socket design for a below-knee amputation. Excessive heat and the resulted perspiration within a prosthetic socket were the most common causes for reporting a reduced quality of life for prosthetic users. The product namely AirCirc means air circulation and it has been designed by approach of medical device design process in providing the amputees to maintain the skin temperature inside the socket. This device has been designed to provide the amputees with comfort and ultimate breathable. In order to design the device, the small hole was made in prosthetic socket surface since it has a function as air circulation. Four types of proposed sockets namely P1, P2, P3 and P4 and one control socket were compared on a single patient to determine the best design of prosthetic socket. The result successfully reveals that by using holes can be maintain the temperature inside prosthetic socket. In addition to the eco-friendly material, the woven kenaf was used as material that provides good strength as compared to glass fibre and offer sustainable and biodegradable product yet provides unique and aesthetic surface as came from woven kenaf itself. The objective of this paper is to provide the airflow prosthetic socket design and optimize the use of natural fibre in prostheses field. Thus, with the use of the environmental friendly material, functionality device and heat removal capability make the device suitable for maintaining a comfortable and healthy environment for prosthesis. Newly developed prosthetic leg socket design for a below-knee amputation Device has been designed to provide the amputees with comfort and ultimate breathable Woven kenaf was used as material that provides good strength as compared to glass fibre for sustainable and biodegradable product Results show that by using holes can be maintain the temperature inside prosthetic socket [ABSTRACT FROM AUTHOR]

Hearths were constructed and used at Paleolithic cave and rockshelter sites in Africa, Europe and Asia as early as the late Lower Paleolithic period. The advantages of the use of fire have been widely researched for the last decades. However, only a few studies have focused on the possible negative impact of the use of fire within closed spaces, such as caves. One of the major negative fire products is smoke, which has an immediate, as well as long-term, effect on humans and may even prevent cave occupation after a short period. In this study we propose a basic air circulation model based on thermodynamics to represent smoke ventilation in caves. We employ this model to shed light on the relationship between smoke dispersal and cave structure, opening dimensions, hearth characteristics, and seasonal temperature fluctuations. We further show that hearth location was crucial in allowing humans to occupy prehistoric caves while using fire on a regular basis. We present preliminary insights from specific case studies, demonstrating the potential of understanding smoke ventilation in reconstructing the hearth season of use and location within the cave. [ABSTRACT FROM AUTHOR]

Windbreaks create efficient soil protection against wind erosion particularly at the time when soil cover is not protected by vegetation cover of cultivated plant. The objective of this research was to find correlation between qualitative parameters of windbreaks and their efficiency in terms of wind speed reduction. The wind speed measurement was carried out by 4 stations along windbreak. The station contains 2 anemometers at heights 0.5 and 1 m above the surface. The character of windbreak was described by photogrammetry method as the value of optical porosity from the photo documentation of the windbreak at the time of ambulatory measurement. Important dependency between the value of optical porosity and efficiency of windbreak emerged from the results. An important protective effect of windbreak on soil was proven on the leeward side of the windbreak in the belt corresponding with approximately six times the height of the windbreaks.

The mean duration of snow coverage in the West Siberian Plain is approximately eight months in the north to about five months in the south. While the period of intense snow melting is short (one or two months between March and May), snow accumulation persists for most of the cold season. Snow accumulation is associated with negative anomalies of sea level pressure, which means increased cyclonal activity and weaker than normal Siberian High. Much lower anomalies of sea level pressure occur during snow ablation. This suggests smaller influence of air circulation on snow cover reduction in spring.

Dropshafts with an internal divider for air circulation are proposed to reduce air entrainment in plunging type dropshafts. Dropshafts typically operate under a pressurized downstream condition and with limited air supply from the top. In this study, experiments were conducted to investigate the performance of the dropshaft with an internal divider under different downstream conditions and air inlet conditions. From the experiments, a pressurized downstream condition would increase the air pressure in the dropshaft, reduce the outside air entrainment while increase the internal air circulation. Reducing the size of the air inlet would decrease the air pressure, meanwhile cause an increase in internal air circulation and a reduction in outside air entrainment. A dimensionless parameter of 'effectiveness factor' was also proposed to measure the effectiveness of the internal air circulation on reducing the outside air entrainment. This study considers the performance of the dropshaft with a divider under the conditions close to real situations, which is important to its design and application. [ABSTRACT FROM AUTHOR]

Mechanical (air-conditioning) ventilation systems and equipment in the food industry may transfer various pathogenic bacteria causing, for instance, pneumonia (Legionellosis). Microclimate parameters in manufacturing shops felt by people are affected by: human factors (health, individual temperature perception etc,) and non-human factors (air physical parameters, air freshness and cleanliness etc.). Microbiological contamination of process equipment, machines and systems such as ventilation and air-conditioning equipment causes growth of pathogenic bacteria. The amount of air supplied and removed from a room depends on its use and load of odours and hazardous material. As a result of dew point formation in ventilation systems may appear the so-called air-borne condensation nuclei on which steam settles when the air gets oversaturated. The air flow rate has a material influence upon comfortable conditions in human inhabited zones. In manufacturing shops where the highest air quality is a priority, radial disinfection by means of catalytic ionization is applied. In food industry manufacturing shops of higher microbiological standard, ventilation systems based on air re-circulation should not be used.

In the present study an attempt was made to determine the degree of effective ventilation of the valleys in the area of the Rybnik Plateau, based on the example of the environs of Jastrzębie Zdrój, a city with high air pollution. For the analysis of the conditions of airing of valleys the areas with different physico-geographical characteristics, primarily in terms of density of the valley network, origin and morphology of the valleys, and type of surface deposits were selected. 49 cross-valley profiles were drawn for the selected valleys; on the basis of the profiles the following parameters were calculated: the distances between the edges of each valley, valley bottom width, and depth of the valleys. The degree of ventilation of each valley was calculated after the formulae of Kaps (1955) and Błażejczyk (1975). The lowest values of the index of effective ventilation were recorded almost in all main loessial valleys in the southern part of the area. This indicates their weak or even extremely weak degree of ventilation. The valleys in the remaining area, open predominantly to N and E, are most commonly aired to a sufficient degree. This is determined by their morphology, especially smaller depth, smaller relative heights and higher mean wind speed. The example presented in this study shows that the index of effective ventilation, even if it is calculated for a relatively small area, reflects the characteristics of the local environment extremely well which is relevant from the perspective of the movement of contaminated air.

In order to solve the problem of growing energy consumption in drying fruits and vegetables and advance the quality of fruits and vegetables processing, a kind of fruits and vegetables dryer was designed based on market demand for the dryer and drying characteristics of fruits and vegetables. The effects of air temperature and relative humidity on the evaporation rate of fruits and vegetables were analyzed, as well as the influence of design parameters on drying uniformity and energy consumption. A structure scheme of static small-sized dryer for fruits and vegetables with circulating airflow was created. Orthogonal test method was used to optimize the structure parameters of the dryer and the uniformity of drying air flow and drying uniformity were monitored by measuring temperature changes of fruits and vegetables. [ABSTRACT FROM AUTHOR]

Ground and air temperature monitoring, geophysical soundings and dendrological investigations were applied to a basaltic talus slope–rock glacier system from Detunata site in the Apuseni Mountains (Western Romanian Carpathians) to verify the presence of sporadic permafrost at 1020–1110 m asl, well below the regional limit of mountain permafrost. The near 0 °C mean annual ground surface temperatures imposed by the large negative annual thermal anomalies of the ground (up to 7.4 °C), together with the high resistivity values and the occurrence of trees with severe growth anomalies, support the presence of permafrost at this location. Temperature measurements and ground air circulation experiments proved that the so-called “chimney effect” is the main process favoring the ground overcooling and allowed for the construction of a model of ground air circulation in complex morphology deposits. The texture and porosity of the debris were quantified along with the local morphology in order to evaluate their role upon the chimney circulation. The debris porosity was found to be very high promoting intense ground overcooling during the cold season, including the periods of high snow cover due to the development of snow funnels. It efficiently reduces the heat transfer during summer thus contributing essentially to permafrost preservation. In compound morphologies, the depressed and low-lying features are the cold zones subjected to winter overcooling and summer chill, while the high-positioned and convex-up landforms become warm air evacuation features with positive thermal anomalies. Tree-ring measurements showed that the growth of cold-affected trees is higher during colder intervals (years to decades) probably as a consequence of the weakened katabatic air outflow during cooler summers. The dendrological analysis of multi-centennial spruces and their growth rates also provided palaeoclimatic inferences for the last 200 years. [ABSTRACT FROM AUTHOR]