G. Ancans, A. Stafecka, V. Bobrovs, A. Ancans and J. Caiko
One of the main objectives of the fifth generation (5G) mobile communication systems, also known as IMT-2020, is to increase the current data rates up to several gigabits per second (Gbit/s) or even up to 10 Gbit/s and higher. One of the possibilities to consider is the use of higher frequencies in order to enlarge the available bandwidth. Wider bandwidth is necessary to achieve much higher data rates. It should be noted that wireless broadband transmission technologies require frequencies for their development.
The main goal of the research is to investigate the characteristics and requirements of 5G mobile communication systems. The paper provides an insight into deployment scenario and radio wave propagation in frequencies above 24 GHz of IMT-2020.
Green building is an important component of sustainable real estate market development, and one of the reasons is that the construction industry consumes a high amount of resources. Energy consumption of construction industry results in greenhouse gas emissions, so green buildings, energy systems, building technologies and other aspects play an important role in sustainable development of real estate market, construction and environmental development. The aim of the research is to analyse environmental aspects of sustainable real estate market development, focusing on importance of green buildings at the industry level and related energy aspects. Literature review, historical, statistical data analysis and logical access methods have been used in the research. The conducted research resulted in high environmental rationale and importance of environment-friendly buildings, and there are many green building benefits during the building life cycle. Future research direction is environmental information process and its models.
Utilisation of biomass is an important factor in reducing emission of greenhouse gases (GHG); at the same time, high efficiency of biomass combustion technologies is to be ensured to minimise the methane (CH4) emission thus achieving the most efficient reduction in the total GHG emission. The authors analyse the GHG emission breakdown in Latvia among the sectors not included in the EU Emissions Trading Scheme (ETS), and, in the context of emission reduction, evaluate the energy supply in the Latvian household sector, the types of combustion technologies and the used fuels. The trend is considered for the CH4 emission factor during 1990-2010 in the household sector of EU countries, and the numerical index is calculated which illustrates decoupling the consumption of biomass fuel from CH4 emission. To evaluate the perspective of CH4 emission reduction in the Latvian household sector, two scenarios are investigated for efficiency improvement as related to the central heating equipment based on wood fuel.
A. Vembris, M. Porozovs, I. Muzikante, J. Latvels, A. Sarakovskis, V. Kokars and E. Zarins
Novel Amorphous Red Electroluminescence Material Based on Pyranylidene Indene-1,3-Dione Derivative
The organic light emitting diode (OLED) is a promising device for future technologies, like flat panel displays and novel light sources. So far the OLED structures have mostly been made by thermal evaporation in vacuum. An alternative approach is to use small molecules which form solid state with glassy structure from solutions. Such compounds can be used in the ink-jet printing technologies and result in reducing the OLED prices.
In this paper, we present an original red fluorescent organic compound 2-(2-(4-(bis(2-(trityloxy)ethyl)amino)styryl)-6-methyl-4H-pyran-4-ylidene)-1H-indene-1,3(2H)-dione (ZWK1), with the maximum of the photoluminescence spectrum for solid state at 657 nm. The structure of the electroluminescent device was ITO/PEDOT: PSS (40 nm)/ZWK1 (120 nm)/LiF (1 nm)/Al (100 nm). The electroluminescence spectra correspond to the CIE coordinates x = 0.65 and y = 0.34 with the maximum at 667 nm. The power and luminance efficiency at the luminance of 100 cd/m2 is 0.43 lm/W and 1.97 cd/A, respectively.
Šipkovs, P. (2009). Zinātne - racionālai energoresursu izmantošanai. Latv. J. Phys. Tec. Sci., 46 (5) 3-15.
Kancevica, L., Navickas, J., Ziemelis, E., & Ziemelis, I. (2006). Increase of the Efficiency of Solar Collectors. In: Biometrics and Information Technologies in Agriculture: Research and Development Conf., (89-92). Kaunas: Lithuanian University of Agriculture.
Pelēce, I. (2010). Modelling of new constructions of solar collectors. In: Applied Informatics and
J. Kalnačs, V. Grehovs, G. Mežinskis and L. Bidermanis
1. Akts Engineering AG (2012). Advanced Kinetics and Technology Solutions . Programme Package „Calisto”.
2. National Institute of Standards and Technology (NIST) Chemistry Web Book. Standard Reference Database 69.
3. Chraska, T., Hostomsk, J., Klementova, M., & Dubsky, J. (2009). Crystallization kinetics of amorphous alumina-zirconia-silica ceramics. Journal of the European Ceramic Society, 29 , 3159-3165.
4. Wurth, R., Pascual, M.J., Mather, G.C., Pablos-Martin, A., Munoz, F
N. Levin, V. Pugachev, J. Dirba and L. Lavrinovicha
The authors analyze the advantages and disadvantages of brushless synchronous electric machines with radially and non-radially mounted rectangular permanent magnets. The results show that the proposed nonradial mounting of permanent magnets considered in the paper, in several cases (e.g. multi-pole brushless generators with tooth windings of the armature) allows achievement of the following advantages: better technology of manufacturing the electric machine owing to simple packing of the stator winding in the stator open slots, which also increases the copper slot fillfactor; reduction in the mass-and-size of permanent magnets at least twice; significantly lower cost of the electric machine; and, finally, its greater specific power.
J. Ekmanis, V. Zebergs, N. Zeltins and V. Vrublevski
Thermal Characteristics of New Building Materials and their Effect upon the Energy Efficiency
The paper formulates the role of thermal inertia of the building materials in the energy supply of buildings and in solution of the energy efficiency problems. The evolution of construction entails the application of new building materials as well as of glazed surfaces in the envelopes of buildings. An analysis is made of the influence of the thermal resistance of building materials and their heat capacity on the thermal inertia indicators of buildings. An inertia scale of buildings has been developed for the choice of the heat supply capacities of buildings at low outdoor temperatures under extreme conditions of the Latvian climate. The ratio of the ventilation capacities has been analysed in the total heating balance at a low thermal inertia of buildings. The significance of innovative ventilation technologies for raising the energy efficiency has been considered.
The structure, composition and magnetic properties of iron oxide nanoparticles are studied as dependent on the synthesis technology and method of separation in ferrofluids. The goal of the present study is to improve the magnetic properties of wet-synthesized nanoparticles and achieve a narrow nanoparticle size distribution. The results of measurements show that by varying the conditions of the chemical coprecipitation method, different compositions and structures of the nanoparticles could be obtained. The separation of ferrite nanoparticles of a polydisperse colloid by centrifugation as well as by HGMS provides the possibility to obtain a nanoparticle set with narrow size distribution
Direct-Drive Synchronous Generators with Excitation from Strontium-Ferrite Magnets: Efficiency Improvement
The authors consider the possibility to raise the specific power of synchronous generators with excitation from inexpensive permanent magnets. For this purpose, it is proposed to use tooth-wise windings and permanent magnets based on inexpensive magneto-hard material, e.g. strontium-ferrite. The magnets are to be placed between the rotor teeth, the alternate polarity of which is facing the air-gap. This provides a simpler and cheaper technology of making such a generator and improves its reliability. The proposed rational bevelling of the stator teeth not only raises the specific power of the generator but also reduces the level of noise and vibrations, extends the longevity of the magnets and bearings as well as facilitates the starting torque of the electric machine, e.g. if it is employed as wind generator.