Production of the Finnish Wind Atlas

The Finnish Wind Atlas was prepared applying the mesoscale model AROME with 2.5 km horizontal resolution and the diagnostic downscaling method Wind Atlas Analysis and Application Programme (WAsP) with 250 m resolution. The latter was applied for areas most favourable for wind power production: a 30 km wide coastal/offshore zone, highlands, large lakes and large fields. The methodology included several novel aspects: (i) a climatologically representative period of real 48 months during 1989–2007 was simulated with the mesoscale model; (ii) in addition, the windiest and calmest months were simulated; (iii) the results were calculated separately for each month and for sectors 30° wide; (iv) the WAsP calculations were based on the mesoscale model outputs; (v) in addition to point measurements, also radar wind data were applied for the validation of the mesoscale model results; (vi) the parameterization method for gust factor was extended to be applicable at higher altitudes; and (vii) the dissemination of the Wind Atlas was based on new technical solutions. The AROME results were calculated for the heights of 50, 75, 100, 125, 150, 200, 300 and 400 m, and the WAsP results for the heights of 50, 75, 100, 125 and 150 m. In addition to the wind speed, the results included the values of the Weibull distribution parameters, the gust factor, wind power content and the potential power production, which was calculated for three turbine sizes. The Wind Atlas data are available for each grid point and can be downloaded free of charge from dynamic maps at www.windatlas.fi . Copyright © 2011 John Wiley & Sons, Ltd.     

Evaluation of a multiple regression model for the forecasting of the concentrations of NOx and PM10 in Athens and Helsinki

Forecasting models based on stepwise multiple linear regression (MLR) have been developed for Athens and Helsinki. The predictor variables were the hourly concentrations of pollutants (NO, NO₂, NO_x, CO, O₃, PM_2.5 and PM₁₀) and the meteorological variables (ambient temperature, wind speed/direction, and relative humidity) and in case of Helsinki also Monin-Obukhov length and mixing height of the present day. The variables to be forecasted are the maximum hourly concentrations of PM₁₀ and NO_x, and the daily average PM₁₀ concentrations of the next day. The meteorological pre-processing model MPP-FMI was used for computing the Monin-Obukhov length and the mixing height. The limitations of such statistical models include the persistence of both the meteorological and air quality situation; the model cannot account for rapid changes (on a temporal scale of hours or less than a day) that are commonly associated, e.g., with meteorological fronts, or episodes of a long-range transport origin. We have selected the input data for the model from one urban background and one urban traffic station both in Athens and Helsinki, in 2005. We have used various statistical evaluation parameters to analyze the performance of the models, and inter-compared the performance of the predictions for both cities. Forecasts from the MLR model were also compared to those from an Artificial Neural Network model (ANN) to investigate, if there are substantial gains that might justify the additional computational effort. The best predictor variables for both cities were the concentrations of NO_x and PM₁₀ during the evening hours as well as wind speed, and the Monin-Obukhov length. In Athens, the index of agreement (IA) for NO_x ranged from 0.77 to 0.84 and from 0.69 to 0.72, in the warm and cold periods of the year. In Helsinki, the corresponding values of IA ranged from 0.32 to 0.82 and from 0.67 to 0.86 for the warm and cold periods. In case of Helsinki the model accuracy was expectedly better on the average, when Monin-Obukhov length and mixing height were included as predictor variables. The models provide better forecasts of the daily average concentration, compared with the maximum hourly concentration for PM₁₀. The results derived by the ANN model where only slightly better than the ones derived by the MLR methodology. The results therefore suggest that the MLR methodology is a useful and fairly accurate tool for regulatory purposes.     

Visible-light-driven photocatalysis with dopamine-derivatized titanium dioxide/<Emphasis Type="Italic">N</Emphasis>-doped carbon core/shell nanoparticles

Titanium dioxide/N-doped carbon core/shell nanoparticles enabling efficient visible-light-driven photocatalytic degradation of rhodamine B, considered a model compound for water-soluble environmental pollutants, were successfully prepared by the carbonization of dopamine-grafted TiO₂ nanoparticles. These precursor nanoparticles were prepared via simple ligand-to-metal charge transfer (LMCT) between TiO₂ nanoparticles and dopamine. Owing to the incorporation of Ti–O–C chelating bonds and the subsequent narrowing of the optical band gap, the dopamine-derivatized photocatalyst demonstrated enhanced activity compared with that of commercial photocatalysts and promoted the photocatalytic degradation of rhodamine B under both UV light and visible light. This LMCT-mediated incorporation of thin amorphous N-doped carbon shells onto the surface of semiconducting photocatalysts may be widely applicable for the generation of novel and robust hybrid materials with enhanced photocatalytic activities for many applications.     

High occurrence of Campylobacter spp. in Latvian broiler chicken production

Campylobacteriosis in humans is caused by thermotolerant Campylobacter spp., most commonly by C. jejuni and C. coli. However, no official data for human campylobacteriosis in Latvia is available or cases are heavily under-reported. In accordance with Commission Decision 2007/516/EC the Campylobacter spp. baseline study was performed in 2008 in Latvia but there was no continuous monitoring for the Campylobacter at broiler chicken production level in 2009. The aim of the present study was to determine the occurrence of Campylobacter spp. in broiler chicken production at slaughterhouse and retail level in Latvia. Poultry samples originated from the two biggest Latvian broiler slaughterhouses. Altogether, 240 fresh broiler chicken neck skins, 2400 intact broiler chicken intestines and 240 fresh broiler chicken carcasses were collected during the year 2010. A total of 92.5% of the pooled intestine samples; 60.8% of the neck skin samples and 56.3% of carcasses were positive for Campylobacter spp. There was seasonal variation in proportions of Campylobacter positive samples with seasonal peak on summer months.     

A Gibbs Energy Minimization Approach for Modeling of Chemical Reactions in a Basic Oxygen Furnace

Metallurgical and Materials Transactions B - In modern steelmaking, the decarburization of hot metal is converted into steel primarily in converter processes, such as the basic oxygen furnace. The...     

An SRWNN-based approach on developing a self-learning and self-evolving adaptive control system for motion platforms

In this paper, a self-recurrent wavelet neural network (SRWNN)-based indirect adaptive control architecture is modified for performing speed control of a motion platform. The transient behaviour of the original learning algorithm has been improved by modifying the learning rate updates. The contribution of the proposed modification has been verified via both simulations and experiments. Moreover, the performance of the proposed architecture is compared with robust RST designs performed on a similar benchmark system, to show that via adaptive nonlinear control, it is possible to obtain a fast step response without degrading the robustness of a multi-body mechanical system. Finally, the architecture is further improved so as to possess structural learning for populating the SRWNNs automatically, rather than employing static network structures, and simulation results are provided to show the performance of the proposed structural learning algorithm.     

Solar ponds for space heating

Solar ponds are shallow bodies of water in which an artificially maintained salt concentration gradient prevents convection. They combine heat collection with long-term storage and can provide sufficient heat for the entire year. We consider the absorption of radiation as it passes through the water, and we derive equations for the resulting temperature range of the pond during year round operation, taking into account the heat that can be stored in the ground underneath the pond. Assuming a heating demand of 25000 Btu/degree day (Fahrenheit), characteristic of a 2000 ft² house with fair insulation, and using records of the U.S. Weather Bureau, we carry out detailed calculations for several different locations and climates. We find that solar ponds can supply adequate heating, even in regions near the arctic circle. In midlatitudes the pond should be, roughly speaking, comparable in surface area and volume to the space it is to heat. Under some circumstances, the most economical system will employ a heat pump in conjunction with the solar pond. Cost estimates based on present technology and construction methods indicate that solar ponds may be competitive with conventional heating.     

Performance Analysis of Combined mMCSK–mMFSK Modulation in AWGN and Rayleigh Fading Channel

As there are many use cases considered for robotics communications, the data rate variation may be very large. Some sensor applications may require very low data rate, telemetry data may require low-to-medium data rates and e.g. video application will require high data rates. On the other hand, robots may have to operate in very difficult radio propagation environments such as nuclear power plants or industrial facilities. To combat difficult propagation characteristics, an often used and well known mechanism is to use spread spectrum signal structures. Thus in this paper a novel modulation method is considered which offers the inherent signal structure and processing opportunities of spread spectrum signal and at the same time offers an easy mechanism to adapt the data rate from low to high depending on the requirement at hand thus addressing two important communication requirements for robotics. The introduction of $m$ MFSK generated the idea of applying the given approach to other modulation methods. To further enlarge the modulation alphabet sizes (with the price of larger spectrum usage) it was realized that combining the $m$ MFSK and $m$ MCSK would be an interesting choice. The $m$ MCSK– $m$ MFSK modulation is hence considered. A method to analyze this two-component modulation is developed and the performance analyses give results for $m$ MCSK– $m$ MFSK modulation in AWGN and flat Rayleigh fading channels for both coherent and non-coherent receivers. The performance was also assessed with orthogonal and non-orthogonal code constructs for coherent receiver.     

Experimental and numerical studies of liquid dispersal from a soft projectile impacting a wall

A medium-scale IMPACT test programme is currently being implemented at the Technical Research Centre of Finland (VTT). In these tests, deformable cylindrical steel or aluminium projectiles impact a solid concrete wall or a steel force plate. One part of the test is conducted with a missile filled with liquid water to study liquid dispersal phenomena (i.e., wet missile tests).The fluid-filled missile ranged in length from 0.5 to 1.5 m, the water mass inside the missile from 15 to 68 kg, and the impact velocity of missile from 70 to 177 m/s.This paper describes the methods used to measure the liquid dispersal processes, and presents the main results for preliminary simulations of liquid spread. Because the IMPACT tests have focused on structural aspects, it was necessary to develop cost-effective methods for measuring liquid phenomena. The tests measured some important parameters associated with liquid: the discharge speed and direction of the liquid core released from the ruptured missile, propagation speed of the spray front, liquid pooling on the floor, extent of liquid dispersal away from the target, and the drop size of the liquid spray.The experimental findings indicate that the liquid release starts along the surface almost perpendicularly to the incoming direction of the missile and forms a fairly “flat” and uniform splash pattern around the missile. Although the discharge speed of the liquid core may be initially much higher than the impact velocity of the missile, the propagation speed of the spray front decreases rapidly with increasing distance from the source. Results of the preliminary simulations show that the Fire Dynamic Simulator (FDS) program is a usable tool for simulating two-phase flows involving high-speed droplets, provided that the initial conditions (angle and speed of liquid release, droplet size, and initial air speed) can be specified appropriately. Given these requirements, FDS can reasonably well predict the formation of the water spray cloud and final distribution of water.