Tunnel ventilation is the design practice of placing exhaust fans and air inlets on opposite ends of animal production facilities and moving air through the building via negative pressure. Increasing air velocity within tunnel ventilated broiler production facilities increases sensible cooling and reduces the need for latent cooling (panting), which improves production efficiency. An air velocity measurement system was developed and measurement density analysis for quantifying air velocity distribution was performed in a 12.19 x 121.9 m commercial broiler production facility. Results showed that axial measurement distances of 3.05 m and 40 measurement points per cross-section produced the most descriptive air velocity distribution maps. Air velocity distribution, mean cross-sectional air velocity, and total facility air flow was assessed in three tunnel ventilated commercial broiler production facilities. These facilities differed in size, design, and equipment configurations (test facility 1 was 18.3 × 170.7 m, test facility 2 was 15.24 × 144.8 m, and test facility 3 was 12.19 × 121.9 m). Air velocity distribution varied within all three facilities. Normalized cross-sectional air velocity was plotted against proportion of total house length to compare the cross-sectional air velocity of the three facilities. House width and physical arrangement of the feed hoppers, heating systems, and tunnel fans are impacting air velocity uniformity and mean cross-sectional air velocity in the three broiler houses. Precision Livestock Farming (PLF) seeks to improve production efficiency and animal well-being by model based control of animal production facilities. Four broiler production facilities were assessed for spatial bird body weight (BW) variability. The facilities were 15.24 × 144.8 m solid side-wall tunnel ventilated broiler houses containing birds at 58 and 59 d of age. Significant differences in BW were found between birds residing at center house (3.47 kg average) and at the side-walls (3.38 kg average) (P = 0.025). This variability in BW could be attributed to any number of environmental, nutrient, or behavioral causes. A discussion of input/control parameters for PLF management of broiler production is presented. Quantification of performance variability within these facilities and defining models for control of input parameters is essential to making PLF management feasible.

The role of nitric acid (HNO3) on the atmospheric corrosion of metals has so far received little or no attention. However, the last decades of decreasing sulphur dioxide (SO2) levels and unchanged HNO3 levels in many industrialized countries have resulted in an increased interest in possible HNO3-induced atmospheric corrosion effects. In this study a new method was developed for studying the corrosion effects of HNO3 on metals at well-defined laboratory exposure conditions. The method has enabled studies to be performed on the influence of individual exposure parameters, namely HNO3-concentration, air velocity, temperature and relative humidity, as well as comparisons with newly generated field exposure data. The corrosion rate and deposition rate of HNO3 on copper was shown to follow a linear increase with HNO3 concentration. The deposition velocity (Vd) of HNO3 increased up to an air velocity of 11.8 cm s-1. Only at a higher air velocity (35.4 cm s-1) the Vd on copper was lower than the Vd on an ideal absorbent, implying the Vd of HNO3 at lower air velocities to be mass-transport limited. Within the investigated temperature range of 15 to 35 ºC only a minor decrease in the HNO3-induced copper corrosion rate could be observed. The effect of relative humidity (RH) was more evident. Already at 20 % RH a significant corrosion rate could be measured and at 65 % RH the Vd of HNO3 on copper, zinc and carbon steel reached maximum and nearly ideal absorption conditions. During identical exposure conditions in HNO3-containing atmosphere, the corrosion rate of carbon steel was nearly three times higher than that of copper and zinc. The HNO3-induced corrosion effect of copper, zinc and steel turned out to be significantly higher than that induced by SO2 alone or in combination with either NO2 or O3. This is mainly attributed to the much higher water solubility and reactivity of HNO3 compared to SO2, NO2 and O3. Relative to SO2, zinc exhibits the highest sensitivity to HNO3, followed by copper, and carbon steel with the lowest sensitivity. Extrapolation of laboratory data to an assumed average outdoor wind velocity of 3.6 m s-1 enabled a good comparison with field data. Despite the fact that ambient SO2 levels are still much higher than HNO3 levels, the results show that HNO3 plays a significant role for the atmospheric corrosion of copper and zinc, but not for carbon steel. The results generated within this doctoral study emphasize the importance of further research on the influence of HNO3 on degradation of other materials, e.g. stone and glass, as well as of other metals.

<p>The role of nitric acid (HNO₃) on the atmospheric corrosion of metals has so far received little or no attention. However, the last decades of decreasing sulphur dioxide (SO₂) levels and unchanged HNO₃ levels in many industrialized countries have resulted in an increased interest in possible HNO₃-induced atmospheric corrosion effects. In this study a new method was developed for studying the corrosion effects of HNO₃ on metals at well-defined laboratory exposure conditions. The method has enabled studies to be performed on the influence of individual exposure parameters, namely HNO₃-concentration, air velocity, temperature and relative humidity, as well as comparisons with newly generated field exposure data.</p><p>The corrosion rate and deposition rate of HNO₃ on copper was shown to follow a linear increase with HNO3 concentration. The deposition velocity (Vd) of HNO₃ increased up to an air velocity of 11.8 cm s^-1. Only at a higher air velocity (35.4 cm s^-1) the Vd on copper was lower than the Vd on an ideal absorbent, implying the Vd of HNO3 at lower air velocities to be mass-transport limited.</p><p>Within the investigated temperature range of 15 to 35 ºC only a minor decrease in the HNO₃-induced copper corrosion rate could be observed. The effect of relative humidity (RH) was more evident. Already at 20 % RH a significant corrosion rate could be measured and at 65 % RH the Vd of HNO₃ on copper, zinc and carbon steel reached maximum and nearly ideal absorption conditions.</p><p>During identical exposure conditions in HNO_3-containing atmosphere, the corrosion rate of carbon steel was nearly three times higher than that of copper and zinc. The HNO₃-induced corrosion effect of copper, zinc and steel turned out to be significantly higher than that induced by SO2 alone or in combination with either NO₂ or O₃. This is mainly attributed to the much higher water solubility and reactivity of HNO3 compared to SO₂, NO₂ and O_3. Relative to SO₂, zinc exhibits the highest sensitivity to HNO₃, followed by copper, and carbon steel with the lowest sensitivity.</p><p>Extrapolation of laboratory data to an assumed average outdoor wind velocity of 3.6 m s-1 enabled a good comparison with field data. Despite the fact that ambient SO₂ levels are still much higher than HNO₃ levels, the results show that HNO₃ plays a significant role for the atmospheric corrosion of copper and zinc, but not for carbon steel. The results generated within this doctoral study emphasize the importance of further research on the influence of HNO₃ on degradation of other materials, e.g. stone and glass, as well as of other metals. </p>

No description available.

Air velocities induced by underground vehicles in complex metro systems are obtained using artificial neural networks. Complex tunnel shaft-systems with any number of tunnels and shafts and with most of the practically possible geometries encountered in underground structures can be simulated with the proposed method. A single neural network, of type feed-forward back propagation, with a single hidden layer is trained for modelling a single tunnel segment. Train and tunnel parameters that have influence on the vehicle induced flow characteristics are used together to obtain non-dimensional input and target parameters. First input parameter is the major head loss coefficient of tunnel, (L/D)_Tunnel. Blockage ratio A_Train/A_Tunnel and train aspect ratio (D/L)_Train are selected to be non-dimensional input parameters to represent the system geometry. As the final input parameter, skin friction coefficient of the train, f_Train drag coefficient of the train, C_D / frontal area of the train, A_Train and lateral area of the train, A_Lateral are combined into a single overall drag coefficient based on the train frontal area. Non-dimensional V_Air/V_Train speed ratio is selected to be the target parameter. Using maximum air velocity predicted by the trained neural network together with non dimensional system parameters and time, an additional neural network is trained for predicting the deceleration of air in case of train stoppage within the tunnel system and departure of the train from the system. A simulation tool for predicting time dependent velocity profile of air in metro systems is developed with the trained neural networks.

This thesis proposes a novel air flow sensor based on PZT material which is used to measure air velocity in an experimental tunnel or indoor ventilation. The work focuses on designing and verifying the sensor model through finite element analysis (FEA) simulation using COMSOL Multiphysics software. This thesis is devoted to developing a sensor model with a focus on a low-velocity range up to 2 m/s and high sensitivity. The design of the sensor should be robust and reliable for different flow patterns, temperature, and atmospheric pressure variation. The sensor model consists of a fixed cylinder which connects with a bilayer cantilever made of PZT and PDMS material. The laminar flow from the sensor inlet is transformed into the turbulent flow when passing by the fixed cylinder. This structure of bilayer cantilever is designed to generate self-induced oscillation on PZT to overcome the charge leakage over the sensor impedance. Resonance optimization of the sensor structure is investigated to obtain better SNR and performance by adjusting the dimension of the cantilever. From the conducted simulation results, the relationship between the dominant frequency of output voltage generated by PZT and air velocity can be described linearly. In conclusion, it is shown that proposed sensor has a sensitivity of 0.1 m/s and a range of 0.2 to 2 m/s.

This thesis consists of description of design and construction of device for measuring air velocity created in it´s practical part. In introduction is mentioned basic theoretical information related to given problem, in the next chapters is descripted design and construction of measuring device along with description of calibration proces. At the end is placed chapter about testing the final device.

The objective of this diploma thesis is optimization of the current state of internal microclima-te, which was supported by CFD simulations. The solved object is storage hall of electronics of the the company ebm-papst CZ s.r.o.

Människans välmående och förmåga att prestera optimalt påverkas av inomhusklimatet. de främsta faktorerna som påverkar människans upplevelse av detta är luftkvalitet, ljus och ljudnivåer.I den här rapporten vill vi ta reda på hur en byggnad som vi har valt lever upp till de krav som ställs på inomhusklimatet, ta reda på hur personer i byggbranschen ser på/värderar inomhusklimatet och hur det arbetar för att uppfylla kraven på ett bra inomhusklimat. För att ta reda på detta har vi använt oss av handlingar för det huset vill valt, intervjuer med branschfolk samt en enkätundersökning som delats ut till brukarna av byggnaden.Byggnaden uppfyller de krav som ställs på ljud, ljus, luftkvalité, värmekomfort på vinterhalvåret och värmekomfort på sommarhalvåret enligt miljöbyggnad gulds kriterier för projekterande värden. Enligt vår enkät undersökning med 46 deltagare där frågor som tagits fram av Sweden Green Building Council som handlar om hur nöjda brukarna är med inomhusklimatet klarade ljud, ljus och luftkvalitet kraven på nöjdhet som ska vara minst 80 % av deltagarna. Värmekomforten i byggnaden klarade däremot inte kraven på både vinter och sommarhalvåret.Slutsatsen från den här studien är att i byggnaden överlag håller en hög standard men att det går att göra förbättringar i värmesystemen i form av injusteringar av ventilation och sekundärvärme. Deltagarna var väldigt nöjda med dagsljus och vi kom fram till slutsatsen att på grund av de stora fönsterytorna som skapar detta är det svårt att få en bra värmekomfort i fastigheten då alla typer av öppningar för med sig värmeförluster.De företag och personer vi har varit i kontakt med jobbar alla aktivt med inomhusklimat frågor både i projekteringsstadiet och i brukar stadiet. De ser alla en positiv framtid för den fortsatta utvecklingen av inomhusklimatet och att det är en av de viktigaste frågor man ställs inför vid uppförande av fastigheter. / Human well-being and ability to perform optimally are affected by the indoor climate. The main factors that affect the human experience of this are air quality, light and noise levels.In this report we want to find out how a building we have chosen meets the requirements of the indoor climate, find out how people in the construction industry are looking at/appreciating the indoor climate and how they work to meet the requirements for a good indoor climate. To research this we have used documents from the house we choose, interviews with industry people and a survey conducted to the users of the building.The building meets the requirements for sound, light, air quality, warmth comfort during the winter and heat comfort during the summer months according to the environmental building gold criteria for projected values. According to our survey, a survey of 46 participants where questions raised by the Swedish Green Building Council, which deal with how satisfied the users are with the indoor climate, sound, light and air quality achieved the satisfaction requirements that should be at least 80%. However, the heating comfort in the building did not meet the demands in winter and summertime's.The conclusion from this study is that the building in general has a high standard but that improvements in heating systems can be made in form of adjustments of ventilation and secondary heating. The participants were very happy with daylight and we came to the conclusion that because of the large windows that create this, it is difficult to get a good heating comfort in the property as all types of openings bring heat losses.The companies and people we have been in contact with, all actively work with indoor climate issues, both at the design stage and at the user stage. They all see a positive future for the continued development of the indoor climate and that it is one of the most important issues facing the construction of real estate

The thesis deals with evaluation of the environmental thermal state in closed rooms with people inside the room. The achievement of thermal comfort is related to thermal balance of human body. People are producing heat during their work, which has to be carried away from the body to surrounding area by radiation, convection, conduction, respiration and evaporation. The intensity of heat removal is influenced by environmental parameters, especially by air temperature, mean radiant temperature, air velocity and humidity. Personal factors as energy expenditure of human body and clothing resistance are influencing the intensity of heat removal as well. People are able to influence the thermal comfort by their behaviour in given environment, appropriate clothing and regulation of basic environmental parameters. CSN EN ISO 7730 standard states that environmental parameters should be estimated or measured. The operative temperature is than evaluated from collected data. This operative temperature is defined as the temperature of black enclosed area where the human body will be by convection and radiation sharing the same amount of heat as in real inconsistent environment. Nowadays on the market there is no cheap solution for sensor which is able to evaluate the operating temperature and could be used in buildings. There are a lot of professional sensors which have very high accuracy, but are very expensive. Therefore are mainly used only for research or for single and exceptional measurement of environmental thermal state in rooms. The thesis is therefore focused on proposal of suitable (compact) operative temperature sensor assembled according to valid regulations and standards. Emphasis is placed mainly on the sensor price together with guarantee of sufficient accuracy. The proposed sensor is providing information to control system which is than able to adjust the parameters of environment using appropriate way based on relevant requirements. Here is some space for energy savings due to possible continuous measurement and evaluation of environmental thermal state in different rooms. Therefore, during continuous measurement no unnecessary rooms overheating in winter as well as unreasonable cooling in summer should occur. This research and solution is than reflected in reduction of energy consumption used for building operation and subsequently reduction of the pollutants production. This issue is being watched with increasing interest. Another advantage is that whole system is able to work autonomously without human intervention. People no longer have to continuously adjust air temperature because the control system is able to evaluate the most appropriate adjustments based on objective data obtained from the sensor. The thesis includes subsequent verification of proposed sensor as well as the definition of sensor technical parameters including analysis of measurement uncertainties.