Externally programmed variable timer

Device satisfies 1-sec, 5-sec, and 10-min timing requirements. Temperature and voltage range accuracy is plus or minus 3.9 percent with voltage variations of 24 to 31 Vdc over temperature range of minus 55 deg C to plus 125 deg C

Social Networks in Regulation Learning Process Quality

Successful web-based learning depends on several key factors. These include the quality of the learning tools, the motivation of users, and the credibility of the learning materials as well as their significance in the eyes of users. It is possible to find numerous examples of web-based lifelong learning approaches that can be viewed on social networks and discussion forums. The research for this study included designing several blog-based discussion forums where user activities were logged and the results were compared to usercompleted questionnaires for similar activities. Several user behaviour identification models were designed based on algorithmically computed tallies of user behaviours. These models are currently being applied for further study to measure user behaviours in virtual learning environments

Generation of Woodgas and its Rational Use for Combined Power and Heat Production at Rural Enterprises

During the last few years combined production of electricity and heat based on biomass gasification technology and on gas utilization in gas-fired engines has been widely reconsidered. This method is more sustainable and environmentally friendly provision of energy in the future. Latvia is rich in forests and the wood processing industry is developing very fast, giving about 4.5 mill. m3 of woods residue per year. The use of wood residue does not follow the increase of wood production. In Latvia we have abundant biomass resources such as wood harvesting and wood processing residues, waste wood and sawdust. As a first attempt to introduce biomass gasification technology in Latvia some researchers at the faculty of engineering of LUA are developing an integral small scale combined heat and power (CHP) system based on a used Russian-made diesel-alternator set with electrical output 100 kWe. The diesel is converted to dual fuel gas engine, using producer gas as the main fuel and gas oil as pilot fuel. To get sufficiently clean (tar content ? 250 mg/m3) woodgas for using in IC engine a downdraft type of gasifier was chosen designed and constructed on the “IMBERT” gasifier principles. The test runs of the first experimental model showed that the engine does not develop expected power because of high resistance of gasifier and gas cleaning system does not work sufficiently enough. There was rather high level of tar content in woodgas because the temperature in the reduction zone was to low. Calculations were carried out and a new technological scheme of gasification system was worked out, introducing innovative ideas aimed on improving the working parameters. The experiments and calculations showed that such a type of CHP plant could be a technologically and economically interesting option for small sawmills and farms in rural areas

ECOLOGICAL IMPACT OF BIODIESEL USE

The paper presents a study of biodiesel application and its ecological impacts. Our study is based on the comparison of exhaust emission composition produced by the combustion of rapeseed oil methyl ester (RME) and conventional diesel fuel (DD) and its blends in a direct injection diesel engine XD2P (YTT). The engine was tested in biofuels laboratory of LUA Motor Vehicle Institute. Fueling the engine with biodiesel and biodiesel/diesel blend reduced oxides of nitrogen by 17.5% (100RME) and by 5.6% (35RME) and carbon monoxide by 49.8% (100RME) and by 45.3% (35RME). Fueling the engine with biodiesel and different biodiesel/diesel blends reduced the absorption coefficient by 33.9% (5RME), by 44.3% (20RME), by 48.3% (35RME) and by 51.2% (100RME) on free acceleration regime. In these tests soot reduced by 28...76.7% at full opened throttle position with 100RME

Physical and dynamical characterisation of low Delta-V NEA (190491) 2000 FJ10

We investigated the physical properties and dynamical evolution of Near Earth Asteroid (NEA) (190491) 2000 FJ10 in order to assess the suitability of this accessible NEA as a space mission target. Photometry and colour determination were carried out with the 1.54 m Kuiper Telescope and the 10 m Southern African Large Telescope during the object's recent favourable apparition in 2011-12. During the earlier 2008 apparition, a spectrum of the object in the 6000-9000 Angstrom region was obtained with the 4.2 m William Herschel Telescope. Interpretation of the observational results was aided by numerical simulations of 1000 dynamical clones of 2000 FJ10 up to 10^6 yr in the past and in the future. The asteroid's spectrum and colours determined by our observations suggest a taxonomic classification within the S-complex although other classifications (V, D, E, M, P) cannot be ruled out. On this evidence, it is unlikely to be a primitive, relatively unaltered remnant from the early history of the solar system and thus a low priority target for robotic sample return. Our photometry placed a lower bound of 2 hrs to the asteroid's rotation period. Its absolute magnitude was estimated to be 21.54+-0.1 which, for a typical S-complex albedo, translates into a diameter of 130+-20 m. Our dynamical simulations show that it has likely been an Amor for the past 10^5 yr. Although currently not Earth-crossing, it will likely become so during the period 50 - 100 kyr in the future. It may have arrived from the inner or central Main Belt > 1 Myr ago as a former member of a low-inclination S-class asteroid family. Its relatively slow rotation and large size make it a suitable destination for a human mission. We show that ballistic Earth-190491-Earth transfer trajectories with Delta-V < 2 km s^-1 at the asteroid exist between 2052 and 2061.Comment: 2 Tables, 11 Figures, accepted for publication in Astronomy & Astrophysic

KOKSNES BIOMASAS GAZIFICĒŠANAS SISTĒMA MAZAS JAUDAS KOĢENERĀCIJAS MOTORSTACIJĀ

Pēdējo desmit gadu laikā Eiropā populāras kļuvušas mazas jaudas (0,1 - 0,5 MW) koģenerācijas motorstacijas, kurās izmanto ar dabasgāzi darbināmus iekšdedzes motorus kombinētai siltuma un elektrības ražošanai. Motorstacijas plaši izmanto atsevišķu uzņēmumu, fermu, saimniecību, ciematu, hospitāļu, kempingu u.c. lokālai elektrības un siltuma apgādei. Latvijā patreiz jau darbojas divas šādas koģenerācijas motorstacijas Ādažos (ar elektrisko jaudu 344 kW) un Lielvārdē (165 kW).

Spectral and Spin Measurement of Two Small and Fast-Rotating Near-Earth Asteroids

In May 2012 two asteroids made near-miss "grazing" passes at distances of a few Earth-radii: 2012 KP24 passed at nine Earth-radii and 2012 KT42 at only three Earth-radii. The latter passed inside the orbital distance of geosynchronous satellites. From spectral and imaging measurements using NASA's 3-m Infrared Telescope Facility (IRTF), we deduce taxonomic, rotational, and physical properties. Their spectral characteristics are somewhat atypical among near-Earth asteroids: C-complex for 2012 KP24 and B-type for 2012 KT42, from which we interpret the albedos of both asteroids to be between 0.10 and 0.15 and effective diameters of 20+-2 and 6+-1 meters, respectively. Among B-type asteroids, the spectrum of 2012 KT42 is most similar to 3200 Phaethon and 4015 Wilson-Harrington. Not only are these among the smallest asteroids spectrally measured, we also find they are among the fastest-spinning: 2012 KP24 completes a rotation in 2.5008+-0.0006 minutes and 2012 KT42 rotates in 3.634+-0.001 minutes.Comment: 4 pages, 3 figures, accepted for publication in Icaru

DEVELOPMENT OF HUMAN BALANCE CAPABILITY TESTING PROTOTYPE

The detection of human balance functional disorders may provide some kind of awareness or even warning about potential problems for human health both in organs responsible for ensuring the balance function and in organs related to fulfilment of other important life functions. Modern world offers some sophisticated solutions which enable not only determination of the human balance functional capacity but also offer some kind of training environment to provide corresponding rehabilitation. Unfortunately, such systems are very expensive. And this make limitations of their accessibility and practical usability for a wide range of the target group / population. Software solutions, including mobile applications, on the other hand, are incomparably cheaper. However, they do not allow to make precise balance capability measurements, limiting to simplified balance retention simulators. During implementation of the Latvian National State Research Program VPP INOSOCTEREHI from 2015 to 2017 three human balance capability testing prototypes were developed using a variety of electronic and mechatronic solutions. The last one was successfully approbated during two pilots in Latvian schools in 2016 and demonstrated at the International Invention and Innovation Exhibition MINOX-2016. This paper analyses benefits and disadvantages of approaches used in creating of these prototypes. Besides, authors make initial comparison of developed third prototype version against the BioSway system offered in the market. The paper gives also insight into particular system interface development and new effective graphic portrayal of the balance testing output data, as well as sets the goals for further possible commercialization of the developed balance testing prototype

The contribution of maternal serum markers in the early prenatal diagnosis of molar pregnancies

The aim of this study was to evaluate the usefulness of maternal serum markers in the early prenatal diagnosis of molar pregnancies. The ultrasound features, cytogenetic and histopathological findings of 10 cases of molar pregnancy diagnosed at 11-13 weeks of gestation were compared retrospectively with the maternal serum concentrations of human chorionic gonadotrophin (HCG), alpha fetoprotein (AFP), pregnancy-associated plasma protein A (PAPP-A) and pregnancy-specific β1-glycoprotein (SP1). Free β-HCG and intact HCG concentrations were very high [≥ISOdia≥2.5 multiples of the median (MoM)] in all cases. AFP concentrations were extremely low in all cases of singleton complete moles (≤ISOdia≤0.5 MoM) and were high in one case of twin complete mole, in one case of triploid partial mole and two cases of euploid partial mole (≥ISOdia≥2.5 MoM). Serum PAPP-A and SP1 were high in complete moles. The combined use of ultrasound features, maternal serum proteins and fetal cytogenetic findings should enable the early differential diagnosis in utero and perinatal management of those molar pregnancies presenting with an anatomically normal fetu