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Risks Impact on the Accommodation and Food Services: The Case of Latvia
No full textThe target of this work is to research risks impact on the commercial activity of the accommodation and food services sector’s enterprises. Classification of technological process risks of the accommodation (hotel) and food services are created in the article. The authors have carried out a survey of the most important risks’ factors in the stages of the technological process. Classification of Latvian accommodation and food services sector’s economic and financial risks are created in the period from year 2012 till year 2013. Risks ranking method, experts’ method and special coefficient method are used to analyse risks impact on Latvian accommodation and food services sector enterprises’ development. The risks matrixes are used as risks assessment tools. Risks are arranged by the size of potential losses. The risks assessments by using the special coefficient method are made in the period from year 2007 till year 2012. The authors have offered rating of external and internal risks by their impact on the commercial activity of enterprises. The authors have used their own created model of enterprises’ risks identification, classification and assessment that to research risks impact on Latvian accommodation and food services sector enterprises’ development
Features of Using the Russian State Standards and the Eurocodes for the Protection and Repair of Concrete Structures
No full textThe corrosion is one of the main deterioration reasons of structural concrete and
reinforced concrete. The corrosion is a consequence of unsatisfactory construction maintenances,
poor diagnosis of defects' causes and no fracture control of concrete structures and also incorrect
repair specifications and incorrect products and techniques selecting for the repair inevitably lead to
the concrete structures' deterioration. The most countries are taking care to developing of the
national standards for using as manuals for the protection and repair of concrete structures against
corrosion to avoid these negative factors. The article authors are offering the comparative analysis
of the harmonized Russian state standards and Eurocodes for the protection and repair of concrete
structures against corrosion
Сварочные технологии при изготовлении конструкций из металлических перфорированных материалов
No full textDarbā ir dota perforēto metālisko materiālu klasifikācija, ka arī analizēti procesi to iegūšanai. Pētītās metināšanas tehnoloģiju lietošanas iespējas konstrukciju izgatavošanai no perforētiem metāliskiem materiāliem. Īpaša uzmanība veltīta tādu konstrukciju metināšanas no tērauda perforētiem materiāliem, iegūtiem kā atkritumi pēc štancēšanas
Studies of TiO2 Ceramics Structure after Thermal Treatment at Different Conditions
No full textStudies of TiO2 ceramics structure after thermal treatment at different condition
Thermal Growth Influence on the Shaft Alignment of Rotating Machines
No full textThe value of thermal growth has an important index for the shaft alignment of rotating machine. If parts of the machine (working unit and electromotor) are heated identically, then thermal growth is evened and not taken into consideration. But usually a working unit and electromotor have different coefficients of thermal growth and it is very important. In the article temperature growth influence on the shaft alignment of rotating machine is examined
Ķīmiskās reducēšanas ietekme uz grafēna oksīda struktūru un elektrovadītspēju
No full textGrafēna oksīda (GO) reducēšana tiek uzskatīta par vienu no visdaudzsološākajiem ceļiem, kā lielos apjomos iegūt grafēnu. Reducēšanu veic izmantojot nātrija borhidrīdu valences metālu jonu (Co, Mn) klātbūtnē. Reducētā grafēna oksīda (RGO) struktūru raksturo, izmantojot Ramana spektroskopiju. Tiek noteikts daļiņu izmēra sadalījums un dispersijas stabilitāte, kā arī elektriskā pretestība temperatūras diapazonā -150°C līdz 85°C
Designing and Optimization of New Composite Pallet
No full textMetamodeling is generally recognized efficient approach for the optimization problems.
In our case it is used for shape optimization. Due to development of CAD/CAE software and
advanced metamodeling techniques such approach has become highly effective and popular in
recent years. The references to the non parametric approximation methods are commonly given
to solve deterministic problems. For non-deterministic optimization problems, such as in
proposed case of composite pallet structure (Figure 1) that must account for uncertainties, the
optimization should be based on double loop approaches where the uncertainty propagation is
recursively performed inside the optimization iterations. Often the uncertainty estimation for the
given point is based on metamodel, thus allowing reduction of computational time but introducing
additional bias in the estimates. In such approach a single loop kriging based method for
minimizing the mean of an objective function is proposed: the simulation points are calculated in
order to simultaneously propagate uncertainties, i.e., estimate the mean of objective function, and
optimize this mean. This approach is realized in the original code KEDRO for design of
experiments, analysis and multiobjective robust optimizatio
Towards the Effective Reuse-Oriented Release Configuration Process
No full textThe study describes the approach for effective reuse-oriented release configuration process aimed at supporting and effective maintenance of information technology products. Rather often the project is in the situation when there are multiple unsolved or not properly tested changes on the product release date, that were originally planned to be included into the upcoming product version by project management. The main objective of the study is to identify and implement the effective automated solution for building high-quality releases that include not all, but only tested changes. The developed algorithm produces the list of components to be included into the release build based on the list of changes planned for the upcoming release and information from the project code version control and defect tracking systems
Optical Properties of Quantum Cones Formed in Semiconductors by Laser Radiation
No full textNowadays, nanostructures are one of the most investigated objects in semiconductor physics, especially due to Quantum confinement effect in quantum dots (0D), quantum wires (1D) and quantum wells (2D). A new laser method elaborated for quantum cones formation in semiconductors is reported. A cone possesses the following unique properties: a small cone is a quantum dot – 0D and a long one is a quantum wire – 1D with the gradually decreasing diameter from the base till the top of the cone. Everywhere radii of cone are equal or less than Bohr’ radius of electron, exciton or phonon Quantum confinement effect takes place. Quantum cones on the surface of elementary semiconductors Si and Ge single crystals, and on a surface of of Si1-xGex (x=0.3 and x=0.4) and Cd1-xZnxTe (x=0.1) solid solutions were formed by fundamental frequency and second harmonic of Nd:YAG laser radiation. Strong change of the optical, mechanical and electrical properties of the semiconductors after irradiation by Nd:YAG laser are explained by the presence of Quantum Confinement Effect (QCE) in quantum cones. “Blue shift” of photoluminescence spectra and “red shift” of phonon LO line in Raman spectrum are explained by exciton and phonon QCE in quantum cones, correspondently. Asymmetry of the photoluminescence band in the spectrum of Si quantum cones is explained by 1D graded band gap structure. Experimental data on quantum cones formation on a surface of Si, Ge and their solid solution and CdZnTe crystal and their optical properties are presented. Two-stage mechanism of quantum cones’ formation on a surface of the semiconductors is proposed [1,2]. The first stage of the mechanism is characterized by the formation of a thin strained top layer, due to redistribution of point defects in temperature-gradient field induced by laser radiation. The second stage is characterized by mechanical plastic deformation of the stained top layer leading to arising of quantum cones due to heating up of the top layer.
Formed quantum cones can be applied for design of third generation solar cells, Si white light emitting diode, photon detector with selective or “bolometer” type spectral sensitivity and Si tip for field electron emitting with low work function [3].
References
[1] Artur Medvid, et al., Nanoscale Research Letters, 6, 582(2011).
[2] Artur Medvid’ et al. Nanoscale Research Letters, 8:264(2013).
[3] Artur Medvid’, Laser growth and processing, Edited by N.Vainos, London, (WOODHEAD), 488(2012)
Climate Technologies Concept Implementation into Students Study Works. Cargo Cycle Example
No full textThis paper represents methodology how to implement practical approach into students study works through transition of other countries achievements in climate technologies into Latvian companies. European Union Intelligent Energy Europe projects database is used as a case study. The main results of the case project shows that a case company can minimise the impact to the environment by 40.89 tons of CO2 by replacing cars with cargo bikes for one season. This methodology shows that the students are capable to find new proposals for Latvian companies how to save not only money but also to minimise the impact to the environment