Air flow humidification for air-assisted boom sprayer

The air-assisted ground spray is fairly widespread. However, due to the unpredictable weather conditions, the operational efficiency is impaired by stops on grounds of low humidity and high temperatures. The aim of this work was to assess an air humidification method and evaluate its impact on temperature and air humidity for the air curtain of the air-assisted sprayer. With respect to relative air humidity, it has increased in 6.59%, being the maximum change when inserting 1.92 L min-1. So, it is concluded that the pipeline humidification might significantly reduce temperature and enhance air humidity. The treatments performed in this study consisted of a varied flow of a humidity device, related to weather conditions. Temperature and relative air humidity were measured at 1.0 m height from right to left of middle point of the machine, corresponding to the end of the spray boom, in the middle and end of right spray boom. The readings were also performed at three different distances from the end of the pipeline and at 0.25 and 0.50 m from that to the soil. The results show that 0.48 L min-1 in the humidification system has promoted a better efficiency in reducing air-temperature, on average 2.52 ºC when compared to the non-humidified one.

Automatic system identification and optimization of centrifugal pump operation

Centrifugal pumps are a notable end-consumer of electrical energy. Typical application of a centrifugal pump is the filling or emptying of a reservoir tank, where the pump is often operated at a constant speed until the process is completed. Installing a frequency converter to control the motor substitutes the traditional fixed-speed pumping system, allows the optimization of rotational speed profile for the pumping tasks and enables the estimation of rotational speed and shaft torque of an induction motor without any additional measurements from the motor shaft. Utilization of variable-speed operation provides the possibility to decrease the overall energy consumption of the pumping task. The static head of the pumping process may change during the pumping task. In such systems, the minimum rotational speed changes during reservoir filling or emptying, and the minimum energy consumption can’t be achieved with a fixed rotational speed. This thesis presents embedded algorithms to automatically identify, optimize and monitor pumping processes between supply and destination reservoirs, and evaluates the changing static head –based optimization method.

Theoretical Analysis and Numerical Simulation of Spectral Radiative Properties of Combustion Gases in Oxy/Air-Fired Combustion Systems

Energy efficiency is one of the major objectives which should be achieved in order to implement the limited energy resources of the world in a sustainable way. Since radiative heat transfer is the dominant heat transfer mechanism in most of fossil fuel combustion systems, more accurate insight and models may cause improvement in the energy efficiency of the new designed combustion systems. The radiative properties of combustion gases are highly wavelength dependent. Better models for calculating the radiative properties of combustion gases are highly required in the modeling of large scale industrial combustion systems. With detailed knowledge of spectral radiative properties of gases, the modeling of combustion processes in the different applications can be more accurate. In order to propose a new method for effective non gray modeling of radiative heat transfer in combustion systems, different models for the spectral properties of gases including SNBM, EWBM, and WSGGM have been studied in this research. Using this detailed analysis of different approaches, the thesis presents new methods for gray and non gray radiative heat transfer modeling in homogeneous and inhomogeneous H2O–CO2 mixtures at atmospheric pressure. The proposed method is able to support the modeling of a wide range of combustion systems including the oxy-fired combustion scenario. The new methods are based on implementing some pre-obtained correlations for the total emissivity and band absorption coefficient of H2O–CO2 mixtures in different temperatures, gas compositions, and optical path lengths. They can be easily used within any commercial CFD software for radiative heat transfer modeling resulting in more accurate, simple, and fast calculations. The new methods were successfully used in CFD modeling by applying them to industrial scale backpass channel under oxy-fired conditions. The developed approaches are more accurate compared with other methods; moreover, they can provide complete explanation and detailed analysis of the radiation heat transfer in different systems under different combustion conditions. The methods were verified by applying them to some benchmarks, and they showed a good level of accuracy and computational speed compared to other methods. Furthermore, the implementation of the suggested banded approach in CFD software is very easy and straightforward.

Mikä on air-fligt-periaate?

kuv., 14 x 22 cm

Mikä on air-fligt-periaate?

kuv., 14 x 22 cm

Auton-nostokojeen Lift-a-kar

kuv., 12 x 21 cm

Air policing turvallisuuspoliittisena kysymyksenä Suomessa

Tutkimuksessa tarkastellaan air policingia turvallisuuspoliittisena kysymyksenä Suomessa, Islannin ilmavalvontahankkeen kautta. Tavoitteena oli selvittää Islannin ilmavalvonnasta käydyn julkisen keskustelun perusteella, miten air policing näyttäytyy Suomen turvallisuuspolitiikassa. Air policingilla tarkoitetaan vieraan suvereenin valtion ilmatilan koskemattomuuden valvontaa ja turvaamista rauhan aikana. Suomen turvallisuuspolitiikassa air policing on aiemmin käyttämätön työväline. Tutkimuksessa analysoitiin Suomessa käytyä julkista keskustelua Islannin ilmavalvonnasta. Keskustelua tutkittiin puolustusvoimien lakisääteisten tehtävien ja Suomen sotilaallisen liittoutumattomuuden näkökulmista. Tarkastelujen perusteella tehtiin johtopäätöksiä air policingista Suomen turvallisuuspoliittisena kysymyksenä. Tutkimuksen aineisto koostui Islannin ilmavalvontaa käsittelevistä Helsingin Sanomien, Uuden Suomen, Kylkiraudan ja Sotilasaikakauslehden kirjoituksista, eduskunnan täysistuntojen pöytäkirjoista sekä keskeisten turvallisuuspoliittisten päättäjien lausunnoista. Tarkasteltava ajanjakso oli vuoden 2009 alusta vuoden 2012 loppuun. Tutkimusmenetelmä oli sisällönanalyysi. Islannin ilmavalvonnasta käyty julkinen keskustelu koostui lyhyestä jaksosta vuonna 2009 sekä vilkkaasta ja laaja-alaisesta keskustelusta vuonna 2012. Tärkeimpiä sisältöteemoja olivat Nato ja Suomen liittoutumattomuus sekä pohjoismainen yhteistyö. Keskustelussa muodostui vastakkainasettelu, jossa toinen mielipide kannatti ja toinen vastusti Suomen osallistumista Islannin ilmavalvontaan. Puolustusvoimien lakisääteisiä tehtäviä käsiteltiin julkisuudessa vähän. Sen sijaan Suomen sotilaallinen liittoutumattomuus oli keskustelun ytimessä. Islannin ilmavalvontahankkeen kriitikot katsoivat osallistumisen vaarantavan Suomen liittoutumattomuuden Islannin Nato-jäsenyyden vuoksi. Hankkeen kannattajat perustelivat osallistumisen olevan osan tiivistyvää pohjoismaista puolustusyhteistyötä. Suomen ylin turvallisuuspoliittinen johto on ollut valmis ottamaan käyttöön air policingin Islannin ilmavalvontahankkeen yhteydessä. Kysymys on osoittautunut poliittisesti vaikeaksi, eikä konsensusta ole saavutettu. Maaliskuussa 2013 näyttää siltä, että mahdollinen osallistuminen Islannin ilmavalvontaan toteutuu harjoitusmuotoisena, jolloin siinä ei ole kyse varsinaisesta air policingista.

Mahdollisuudet sisäilmaoireiden poistamiseen huonekohtaisen ilmanpuhdistimen avulla eri aikakauden rakennuksissa

Tämän diplomityön tavoitteena on selvittää sisäilmaongelmien aiheuttajia ja keinoja niiden poistamiseen. Kokeellisessa osuudessa on tavoitteena selvittää kenttämittauksin sisäilman epäpuhtauspitoisuuksia ja ilmanpuhdistimien vaikutusta sisäilman laatuun. Työ toteutetaan kirjallisuustutkimuksen, sisäilmamittauksien sekä asiantuntija- ja sisäilmakyselyjen avulla. Tutkimukseen valittiin viisi erilaisia puhdistustekniikoita käyttäviä ilmanpuhdistimia. Valitut ilmanpuhdistimet olivat viikon ajan viidessä eri koululuokassa, joissa tehtiin sisäilmamittauksia ennen puhdistimen käynnistystä ja sen jälkeen. Luokista kerättiin ilmanäytteitä Andersen keräimellä ja VOC-pumpulla sekä pölynäytteitä pintasivelynä. Tutkimuskohteissa ei havaittu merkittäviä sisäilmaongelmia ja ilmanäytteiden pitoisuudet olivat pääasiassa alhaisia. Poikkeavia sienisukuja ei myöskään esiintynyt valtalajeina. Rakennetutkimukset ja materiaalinäytteet ovat ensisijaisia tutkimusmenetelmiä ongelmakohteissa. Syytä sisäilman aiheuttamaan oireiluun ei vielä tarkalleen tiedetä. Suunnitteluun, valvontaan ja kunnossapitoon tulee panostaa enemmän. Mittausmenetelmiä tulee myös kehittää lisää ja huolehtia ilmanvaihdon toimivuudesta. Tutkimuksia tuleekin tehdä aina kokonaisvaltaisesti.

Experimental analysis of the flow between stay and guide vanes of a pump-turbine in pumping mode

An experimental study was conducted in a pump-turbine model in pumping mode, in order to characterize the flow field structure in the region between stay and guide vanes, using mainly the laser-Doppler anemometry in a two-color and back-scattered light-based system. The structure of the steady and unsteady flow was analyzed. The measurements were performed at three operation points. The obtained data provide appropriate boundary conditions and a good base of validation for numerical codes, and for the understanding of main loss mechanisms of this complex flow.

Static pressure and wall shear stress distributions in air flow in a seven wire-wrapped rod bundle

An experimental investigation is performed in a turbulent flow in a seven wire-wrapped rod bundle, mounted in an open air facility. Static pressure distributions are measured on central and peripheral rods. By using a Preston tube, the wall shear stress profiles are experimentally obtained along the perimeter of the rods. The geometric parameters of the test section are P/D=1.20 and H/D=15. The measuring section is located at L/D=40 from the air inlet. It is observed that the dimensionless static pressure and wall shear stress profiles are nearly independent of the Reynolds number and strongly dependent of the wire-spacer position, with abrupt variations of the parameters in the neighborhood of the wires.

Indoor air quality at a waste incineration plant in Finland

Waste has been incinerated for energy utilization for more than a hundred years, but the harmful emissions emitted from the incineration plants did not begin to cause concern until the 1980s. Many plants were shutdown and the waste incineration plant in Kyläsaari Helsinki was one of them. In later years, new landfill regulations have increased the interest in waste incineration. During the last year, four new plants were taken into operation in Finland, Westenergy in Vaasa among them. The presence of dust has been observed indoors at Westenergy waste incineration plant. Dust is defined as particles with a diameter above 10 μm, while fine particles have a diameter smaller than 2.5 μm, ultrafine under 0.1 μm and nanoparticles under 0.05 μm. In recent years, the focus of particle health research has been changed to investigate smaller particles. Ultrafine particles have been found to be more detrimental to health than larger particles. Limit values regulating the concentrations of ultrafine particles have not been determined yet. The objective of this thesis was to investigate dust and particles present inside the Westenergy waste incineration facility. The task was to investigate the potential pollutant sources and to give recommendations of how to minimize the presence of dust and particles in the power plant. The total particle number concentrations and size distributions where measured at 15 points inside the plant with an Engine Exhaust Particle Sizer (EEPS) Spectrometer. The measured particles were mainly in the ultrafine size range. Dust was only visually investigated, since the main purpose was to follow the dust accumulation. The measurement points inside the incineration plant were chosen according to investigate exposure to visitors and workers. At some points probable leakage of emissions were investigated. The measurements were carried out during approximately one month in March–April 2013. The results of the measurements showed that elevated levels of dust and particles are present in the indoor air at the waste incineration plant. The cleanest air was found in the control room, warehouse and office. The most polluted air was near the sources that were investigated due to possible leakage and in the bottom ash hall. However, the concentrations were near measured background concentrations in European cities and no leakage could be detected. The high concentrations were assumed to be a result of a lot of dust and particles present on surfaces that had not been cleaned in a while. The main source of the dust and particles present inside the waste incineration plant was thought to be particles and dust from the outside air. Other activities in the area around the waste incineration facility are ground work activities, stone crushing and traffic, which probably are sources of particle formation. Filtration of the outside air prior entering the facility would probably save personnel and visitors from nuisance and save in cleaning and maintenance costs.

Energy-efficient control strategies for variable speed driven parallel pumping systems based on pump operation point monitoring with frequency converters

The pumping processes requiring wide range of flow are often equipped with parallelconnected centrifugal pumps. In parallel pumping systems, the use of variable speed control allows that the required output for the process can be delivered with a varying number of operated pump units and selected rotational speed references. However, the optimization of the parallel-connected rotational speed controlled pump units often requires adaptive modelling of both parallel pump characteristics and the surrounding system in varying operation conditions. The available information required for the system modelling in typical parallel pumping applications such as waste water treatment and various cooling and water delivery pumping tasks can be limited, and the lack of real-time operation point monitoring often sets limits for accurate energy efficiency optimization. Hence, alternatives for easily implementable control strategies which can be adopted with minimum system data are necessary. This doctoral thesis concentrates on the methods that allow the energy efficient use of variable speed controlled parallel pumps in system scenarios in which the parallel pump units consist of a centrifugal pump, an electric motor, and a frequency converter. Firstly, the suitable operation conditions for variable speed controlled parallel pumps are studied. Secondly, methods for determining the output of each parallel pump unit using characteristic curve-based operation point estimation with frequency converter are discussed. Thirdly, the implementation of the control strategy based on real-time pump operation point estimation and sub-optimization of each parallel pump unit is studied. The findings of the thesis support the idea that the energy efficiency of the pumping can be increased without the installation of new, more efficient components in the systems by simply adopting suitable control strategies. An easily implementable and adaptive control strategy for variable speed controlled parallel pumping systems can be created by utilizing the pump operation point estimation available in modern frequency converters. Hence, additional real-time flow metering, start-up measurements, and detailed system model are unnecessary, and the pumping task can be fulfilled by determining a speed reference for each parallel-pump unit which suggests the energy efficient operation of the pumping system.

[Air de Laodice]

Soitinnus: lauluääni (sopraano), piano.

Leaf contents of nitrogen and phenolic compounds and their bearing with the herbivore damage to Tibouchina pulchra Cogn. (Melastomataceae), under the influence of air pollutants from industries of Cubatão, São Paulo

The Atlantic Forest on the slopes of Serra do Mar around Cubatão (São Paulo, Brazil) has been affected by massive emissions of pollutants from the local growing industrial complex. The effects of air pollution on the amounts of leaf nitrogen, total soluble phenols and total tannins of Tibouchina pulchra Cogn., a common species in the area of Cubatão, were investigated, as well as the possible influence of the altered parameters on the leaf area damaged by herbivores. Fully expanded leaves were collected at two sites: the valley of Pilões river (VP), characterized by a vegetation virtually not affected by air pollution and taken as a reference; and valley of Mogi river (VM), close to the core region of the industrial complex, and severely affected by air pollution. No differences were observed for any parameters between samples collected in the summer and winter in both sites. On the other hand, compared to VP, individuals growing in VM presented higher amounts of nitrogen and lower amounts of total soluble phenols and total tannins, as well as higher percentages of galls per leaf and higher leaf area lost to herbivores. Regression analysis revealed that the increase in leaf area lost to herbivores can be explained by the increase of the content of nitrogen and decrease in the contents of total soluble phenols and total tannins. Although significant, the coefficients of explanation found were low for all analyses, suggesting that other biotic or abiotic factors are likely to influence leaf attack by herbivores.

Nutrient cycling disturbance in Atlantic Forest sites affected by air pollution coming from the industrial complex of Cubatão, Southeast Brazil

Several aspects of nutrient cycling were studied at two sites of Atlantic Forest, in São Paulo State, Southeast Brazil (23o46’ S; 46o18’ W), which exhibited different degrees of forest structure decline caused by the air pollution emitted by the industrial complex of Cubatão, being referred here as the most and least affected sites (MAS and LAS, respectively). These investigations were developed during 1984 - 1986, a period in which the most severe negative effects of air pollution could be observed. Concentrations and amounts of N, P, K, Ca, Mg and S in four ecosystem compartments (leaves, litter layer, soil and roots) and in rainfall, throughfall and litterfall are briefly presented. At each site, the content of mineral elements generally decreased from leaves to litterfall and litter layer on the forest floor. Soil surface layer (0 - 5 cm) in both sites was the richest in mineral elements. Soil fertility was greater at LAS. In general, nutrient amounts remaining in the compartments and cycling through the ecosystem were greater at LAS as well, which could be due to the higher complexity of the forest structure at this site. Rainfall contributed more to soil inputs of K, Ca, Mg and S than litterfall at both sites. The nutrient residence times in the litter layer were higher and the index of nutrient use efficiency was lower at the most affected site. It was concluded that nutrient cycling was disturbed by air pollution at both sites, but to a greater extent at MAS. The main consequences of the air pollution stress were detected in the flux of nutrients through litterfall and in the litter layer on the forest floor.