18420 research outputs found
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Jūras viļņu enerģijas pārveidotāja iekārta
No full textRakstā izklāstīta jūras viļņu enerģijas pārveidotāja uzbūve un darbības princips
Drug Infiltration in Porous Hydroxyapatite Ceramic and Tissue Response
No full textSintered porous hydroxyapatite (HAp) ceramics were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), optical and scanning electron microscopy (SEM). The samples were saturated with dexamethasone solution (1 mg/ml) or lidocaine solution (5 mg/ml) using vacuum method. To evaluate early reactogenity of porous synthetic impregnated HAp ceramic implants were inserted in holes of rabbit's lower jaws for 2 weeks, 1 month and 3 months. Immunohistochemical methods for evaluation of growth factors and apoptosis were applied. This study aims to further comprehension of reactogenicity of HAp bioceramic implants as bone substitutes in subperiostal environmen
Isotope Effect on Metal-Insulator Transition of (EDO-TTF)2XF6(X=P,As) with Multi-Instability of Metallic State
No full textThe partially deuterated 4,5-ethylenedioxy-tetrathiafulvalene-d2 (EDO-TTF-d2) was synthesized from the undeuterated EDO-TTF-d0. The single crystals of (EDO-TTF-d2)2XF6 (X = P, As) were prepared by the conventional electrocrystallization technique. The deuterium contents of EDO-TTF-d2 itself and the radical cation salts were 99% D by mass spectral analysis. The magnetic susceptibility measurement revealed that (EDO-TTF-d2)2XF6 undergoes a metal–insulator transition at 2–3 K higher temperature than the undeuterated salts. In infrared and Raman spectra, significant isotope shifts were observed not only on C–H vibrational modes but also on TTF-skeletal modes. The assignment of experimental bands was performed on the basis of normal-mode analysis at B3LYP/6-31G(d,p) level of theory
Darba slodze un tās nozīme ķimisko vielu iedarbībā uz organismu
No full textPētīti darba vides riski, kuri saistīti ar ķīmisko vielu lietošanu, šo risku novērtēšana un ar to saistītie faktori. Pētīta un analizēta fiziskā darba slodzes saistība ar izlietoto enerģijas daudzumu un elpošanai patērēto gaisu, kā arī fiziskā darba slodzes lieluma ietekme uz risku, ko rada ar gaisu ieelpoto ķīmisko vielu iedarbība uz organismu. Iegūti pārliecinoši rezultāti, ka, pieaugot fiziskajai darba slodzei, pieaug arī darba vides gaisā esošo ķīmisko vielu un putekļu ietekme uz organismu. Izstrādātas ķīmisko vielu un putekļu radītā riska sakarības saistībā ar darba fiziskās slodzes lielumu, kuras ir praktiski izmantojamas, riska novērtēšanai un samazināšanai
Mathematical Modelling of Brushless Motor Transient
No full textDarbā tiek apskatīts ventiļdzinēja pārējas procesa matemātiskais modelis, kura pamatā ir sinhronās mašīnas matemātiskais modelis. Ventiļdzinēju pārejas procesu analīzes aktualitāti nosaka tas apstāklis, ka daudzu tehnoloģisko procesu kvalitāte un darba ražīgums ir atkarīgs no šo procesu norises ātruma. Piedāvāta ventiļdzinēja struktūras un funkcionāla shēmas. Aplūkots ventiļdzinējs, kas sastāv no sinhronās mašīnas, elektroniskā komutatora, un rotora stāvokļa devēja. Apskatīts ventiļdzinēja matemātiskais modelis ar nemainīgo slodzes leņķi (θ=const) vērtību. Izmantojot sinhronas mašīnas un ventiļdzinēja līdzības uzrakstīti elektriskā kontūra sprieguma līdzsvara vienādojumi uz statora un rotora, ka arī rotora kustības vienādojumi diferenciālā formā. Vienādojumi pierakstīti relatīvas vienības. Darbā piedāvāti palaišanas režīma modelēšanas rezultāti
Effectiveness of Public Investments in Road Traffic Accident Reduction Projects
No full textTransport and communications are an important industry area which facilitates the development of other industries. Transport industry makes up about 7% of the European gros domestic product and about 5% of all jobs. However, notwithstanding its positive influence of the nation's economic welfare, the automobilization causes also such negative phenomena as the air pollution, noise, traffic jams and road traffic accidents (RTA). During the recent years, the number of the registered RTAs has increased. During four years it had grown by more than 25%. The greatest increase was in the period from 2006 till 2007, when the number of RTAs grew by 17%. In 2006, RTAs caused economic damages in the amount of LVL 217,12 million. The aim of this article is to analyze the economic damages, caused by RTAs, identify the factors, influencing road traffic accidents, and analyze the efficiency of the investments into the reconstructed road sections. For better interpretation there is: elaborated a model of interaction between factors which influence road traffic accidents and efforts which should be made to reduce amount of RTAs; there is also made an analyse about the change of RTA in two reconstructed road sections in Latvia. An analyse showed that no road reconstructions with the aim to reduce the number of RTAs are as effective as the change of the traffic participants' behaviour. At the end of the paper are given proposals for minimizing the number of RTAs. Given analysis can be used in future planning of needed investments for reconstructing of motorways and investments for changing human behaviour
Agent-Based Simulation Use in Applicant
No full textThe building of user model based on Agent approach for organising adaptive dialogue is considered in the pape
Changes of Social Environment within the Network o Schools Due to the Unite Project
No full textThe paper presents some research results, formulated as changes of eLearning-based social environment, of the ongoing EU project UNITE (FP6 IST-26964, 2006-2008). One of the distinguishing features of the project is the investigation of sustainability and degree of deployment of project’s results through the creation of the UNITE network of schools (NoS). The NoS provides a social and environmental basis for the investigation and validation of the UNITE framework, i.e., technological platform, the pedagogical models, and the eLearning scenarios that are create, integrated, populated and used in the UNITE schools. The UNITE framework, when introduced into a school, is influential to the social environment of the school, that is the framework causes changes in the social environment. To describe the changes in some well-established manner, we introduce and define some terms and then outline a model for presenting the changes
Mechanics in the Institutions of Higer Education of Latvia
No full textAplūkota mehānikas zinātnes un mācību attīstība Latvijā. Dotas zinātniskās un mācību grāmatas mehānikā
Kritiskie apgriezieni vārpstai, kuras šķēlumam ir dažādi inerces momenti
No full textAplūkota ātras rotācijas vārpsta. Izpētīti kritiskie apgriezieni