scholarly journals Flow-mediated self-organization of ventilation in honeybee nests

2017 ◽  
Author(s):  
Jacob M. Peters ◽  
Orit Peleg ◽  
L. Mahadevan
Keyword(s):  
Air Temperature ◽  
Honey Bees ◽  
Temporal Stability ◽  
Self Organization ◽  
Air Velocity ◽  
Mediated Communication ◽  
Fluctuating Environments ◽  
Large Nest ◽  
Single Opening ◽  
Spatio Temporal

European honey bees (Apis mellifera) live in large congested nest cavities with a single opening that limits passive ventilation. These nests are actively ventilated by individual bees which fan their wings at the nest entrance when the local air temperature exceeds a threshold. Here we show that colonies with relatively large nest entrances use an emergent ventilation strategy where fanning bees self-organize to form fanning groups, separating regions of continuous inflow and outflow. The observed spatio-temporal patterns correlate the air velocity and air temperature along the entrances to the distribution of fanning bees. A mathematical model that couples these variables to known fanning behavior of individuals recapitulates their collective dynamics. Additionally, the model makes predictions about the temporal stability of the fanning group as a function of the temperature difference between the environment and the nest. Consistent with these predictions, we observe that the fanning groups drift, cling to the entrance boundaries, break-up and reform as the ambient temperature varies over a period of days. Overall, our study shows how honeybees use flow-mediated communication to self-organize into a steady-state in fluctuating environments.

scholarly journals Collective ventilation in honeybee nests

2019 ◽  
Vol 16 (150) ◽  
pp. 20180561 ◽  
Author(s):  
Jacob M. Peters ◽  
Orit Peleg ◽  
L. Mahadevan
Keyword(s):  
Air Temperature ◽  
Honey Bees ◽  
Temporal Stability ◽  
Ventilation Strategy ◽  
Air Velocity ◽  
Mediated Communication ◽  
Fluctuating Environments ◽  
Large Nest ◽  
Single Opening ◽  
Spatio Temporal

European honey bees ( Apis mellifera ) live in large congested nest cavities with a single opening that limits passive ventilation. When the local air temperature exceeds a threshold, the nests are actively ventilated by bees fanning their wings at the nest entrance. Here, we show that colonies with relatively large nest entrances use an emergent ventilation strategy where fanning bees self-organize to form groups, separating regions of continuous inflow and outflow. The observed spatio-temporal patterns correlate the air velocity and air temperature along the entrances to the distribution of fanning bees. A mathematical model that couples these variables to known fanning behaviour of individuals recapitulates their collective dynamics. Additionally, the model makes predictions about the temporal stability of the fanning group as a function of the temperature difference between the environment and the nest. Consistent with these predictions, we observe that the fanning groups drift, cling to the entrance boundaries, break-up and reform as the ambient temperature varies over a period of days. Overall, our study shows how honeybees use flow-mediated communication to self-organize into a steady state in fluctuating environments.

scholarly journals Assessment of spatio-temporal variability of rainfall and mean air temperature over Ardabil province, Iran

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Mohammad Ali Ghorbani ◽  
Saba Mahmoud Alilou ◽  
Sahar Javidan ◽  
Sujay Raghavendra Naganna
Keyword(s):  
Air Temperature ◽  
Coefficient Of Variation ◽  
Temporal Stability ◽  
Rain Gauge ◽  
Temperature Data ◽  
Significance Level ◽  
Linear Correlation Analysis ◽  
Spatio Temporal ◽  
Scale Data ◽  
Precipitation And Temperature

AbstractPrecipitation and temperature are the most important climate parameters, which vary both spatially and temporally. In the present study, rainfall data of 11 synoptic stations and 40 rain gauge stations and mean air temperature data of 11 synoptic stations of Ardabil province for the period 2009–2019 collected from the Meteorological Organization of Ardabil province, were considered for investigation. The descriptive statistics of rainfall and temperature such as mean, median, coefficient of variation, skewness and kurtosis were analyzed for monthly scale data. A higher coefficient of variation signified a greater degree of variation in precipitation and temperature data across different months. To evaluate the temporal stability over several months, Pearson linear correlation analysis at a significance level of 5% was performed for each variable. Kriging geostatistical estimator and GIS interface (ArcMap 10.4.1) were used for spatial interpolation with the aid of root mean square and SRMS standards. The results revealed that the spatial variation of temperature was greater than that of precipitation.

Deformation of Potato during Convective Drying

2014 ◽  
Vol 592-594 ◽  
pp. 2728-2732 ◽  
Author(s):  
V.P. Chandramohan ◽  
Prabal Talukdar
Keyword(s):  
Air Temperature ◽  
Drying Shrinkage ◽  
Convective Drying ◽  
Air Velocity ◽  
Maximum Dimension ◽  
Potato Slice ◽  
Generic Solution

Deformation of potato is estimated by experimentally during convective drying. Size of the potato slice is 4cm x 2cm x 2cm. The percentage changes in length, breadth and width of potato are estimated during drying. Shrinkage of the object during drying is estimated. Air velocity chosen for this present analysis is 2 m/s and the range of air temperature is selected as 40 to 70 °C. The product experiences the maximum dimension changes upto 30% in length and 47.5 % in both breadth and width wise. The parameters are non dimensionalised to get generic solution.

Evaluation of the influence of ambient air temperature and air velocity on mortar cement durability using a forced convection solar dryer

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Younes Bahammou ◽  
Mounir Kouhila ◽  
Haytem Moussaoui ◽  
Hamza Lamsyehe ◽  
Zakaria Tagnamas ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Forced Convection ◽  
Air Temperature ◽  
Building Materials ◽  
Ambient Air ◽  
Physical Significance ◽  
Drying Process ◽  
Air Velocity ◽  
Content Type ◽  
Ambient Air Temperature

PurposeThis work aims to study the hydrothermal behavior of mortar cement toward certain environmental factors (ambient air temperature and air velocity) based on its drying kinetics data. The objective is to provide a better understanding and controlling the stability of mortar structures, which integrate the sorption phenomenon, drying process, air pressure and intrinsic characteristics. This leads to predict the comportment of mortar structures in relation with main environmental factors and minimize the risk of cracking mortar structures at an early age.Design/methodology/approachThermokinetic study was carried out in natural and forced convection solar drying at three temperatures 20, 30 and 40°C and three air velocities (1, 3 and 5 m.s-1). The empirical and semiempirical models tested successfully describe the drying kinetics of mortar. These models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures.FindingsThe models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures. The average activation energy obtained expressed the temperature effect on the mortar diffusivity. The drying constant and the diffusion coefficient can be used to predict the influence of these environmental factors on the drying behavior of various building materials and therefore on their durability.Originality/valueEvaluation of the effect of several environmental factors and intrinsic characteristics of mortar structures on their durability.

Experimental and Theoretical Investigation of Performance of a Solar Chimney Model, Part I: Experimental Investigation

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Essaied M Shuia ◽  
Bashir H Arebi ◽  
Ibrahim A abuashe
Keyword(s):  
Experimental Data ◽  
Wind Speed ◽  
Solar Radiation ◽  
Air Temperature ◽  
Solar Collector ◽  
Experimental Results ◽  
Internal Diameter ◽  
Solar Chimney ◽  
Air Velocity ◽  
Collector Temperature

This paper presents the experimental data that was collected from small pilot solar chimney. The experimental data together with ambient conditions are used to evaluate the performance and study the behavior of the solar chimney; this data will be used for comparison with theoretical models in another paper [part II). The solar chimney prototype was designed and constructed at the Subrata Faculty of Engineering-Libya. The data were collected over several days of June 2011. The solar chimney system contains two main components; the solar collector and the solar chimney. The solar collector root‘ has a circular area of126 m3, the solar chimney is a PVC tube with internal diameter of 0.2 m and the total height of chimney is 9.3 m. The measurements include the intensity of solar radiation inside/outside the collector, temperature and velocity of air at the entrance of the chimney, temperature and speed of wind outside the collector, temperature of the ground inside collector al1d temperature measurements of air at speci?c points at different levels throughout the collector. Solar irradiance was found to affect the chimney temperature and subsequently affects chimney air velocity. The experimental results showed that temperature differences of (30 - 45°C) were recorded between the ambient temperature and that of air inside the chimney in the middle of the day, where the highest air temperature of 73.4°C was recorded at the entrance of the solar chimney. The maximum air velocity of 3.6 m/s was recorded inside the solar chimney at noon on 9 June. Wind speed outside the collector had a small effect on the speed of the air inside the chimney and tends to change slightly, hence, can neglect influence of wind speed on the performance of the system. Also the experimental results indicate that such type of system can trap a suf?cient amount of solar radiation, which elevates the air temperature to a suf?cient value able to generate enough air ?ow to operate a wind turbine to produce electricity; this means the solar chimney system for electricity production can work in the north-western part of Libya in the summer time at least.

Temperature Distribution of Hot Air Flow in Heating Zone for Drying Application

2014 ◽  
Vol 627 ◽  
pp. 153-157
Author(s):  
Nawadee Srisiriwat ◽  
Chananchai Wutthithanyawat
Keyword(s):  
Temperature Distribution ◽  
Air Temperature ◽  
Power Supply ◽  
Air Flow ◽  
Heating Zone ◽  
Velocity Control ◽  
Rectangular Duct ◽  
Air Velocity ◽  
Hot Air ◽  
Set Up

The temperature distribution of hot air flow in heating zone of a rectangular duct has been investigated for drying application. The experimental set-up consists of a heater and a fan to generate the hot air flow in the range of temperature from 40 to 100°C and the range of air velocity between 1.20 and 1.57 m/s. An increase of the heater power supply increases the hot air temperature in the heating zone while an increase of air velocity forced by fan decreases the initial temperature at the same power supply provided to generate the hot air flow. The temperature distribution shows that the hot air temperature after transferring through air duct decreases with an increase of the length of the rectangular duct. These results are very important for the air flow temperature and velocity control strategy to apply for heating zone design in the drying process.

Thermal Lethality of Salmonella in Chicken Leg Quarters Processed via an Air/Steam Impingement Oven

2004 ◽  
Vol 67 (3) ◽  
pp. 493-498 ◽  
Author(s):  
R. Y. MURPHY ◽  
K. H. DRISCOLL ◽  
L. K. DUNCAN ◽  
T. OSAILI ◽  
J. A. MARCY
Keyword(s):  
Relative Humidity ◽  
Surface Area ◽  
Air Temperature ◽  
Cooking Time ◽  
Air Velocity ◽  
Poultry Products ◽  
Product Surface ◽  
Cooking Times

Chicken leg quarters were injected with 0.1 ml of the cocktail culture per cm2 of the product surface area to contain about 7 log(CFU/g) of Salmonella. The inoculated leg quarters were processed in an air/steam impingement oven at an air temperature of 232°C, an air velocity of 1.4 m/s, and a relative humidity of 43%. The endpoint product temperatures were correlated with the cooking times. A model was developed for pathogen thermal lethality up to 7 log(CFU/g) reductions of Salmonella in correlation to the product mass (140 to 540 g) and cooking time (5 to 35 min). The results from this study are useful for validating thermal lethality of pathogens in poultry products that are cooked via impingement ovens.

Experimental Modeling of Air Temperature and Velocity Distribution in an Engine Compartment

2006 ◽  
Author(s):  
A. A. Mozafari ◽  
M. H. Saidi ◽  
J. Neyestani ◽  
A. E. Sany
Keyword(s):  
Heat Transfer ◽  
Velocity Distribution ◽  
Air Temperature ◽  
Gasoline Engine ◽  
Point Of View ◽  
Vehicle Body ◽  
Air Distribution ◽  
Wind Effect ◽  
Engine Compartment ◽  
Air Velocity

Investigation of air distribution and wind effect on a vehicle body from the point of view of underhood heat transfer effect and proper positioning of vehicle elements such cooler, condenser and engine configuration is an important area for engine researchers and manufacturers as well. In this research, the effect of air velocity distribution and wind effect around a vehicle is simulated and temperature and velocity distribution around engine block which is influenced by the wind effect is investigated. Thermal investigation of the engine compartment components is performed using results of underhood air temperature and velocity distribution. The heat transfer from engine surface is calculated from the engine energy balance in which their input data are obtained from a comprehensive experimental study on a four cylinder gasoline engine.

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