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Electrical Resistance Change Effect in Polyisoprene/Nanostructured Carbon Composite Induced by Laser Radiation
No full textPolyisoprene/nanostructured carbon (PNC) composites are known for their ability to change electrical resistance rapidly under the influence of mechanical strain and vapour of volatile organic compounds. Previously testing of PNC composites containing carbon black (CB) filler were made to check for the possibility to sense optical radiation. In this study attempt to determine the difference in resistance change response depending on laser wavelength was done. PNC composite samples cyclically were irradiated with laser beams of different wavelengths. Irradiation time during one cycle was 30 s. Measure-ments with sample containing 8 phr of CB showed that relative resistance change effect is larger when irradiating the sample with 532 nm laser beam compared to 980 nm laser beam. To clarify the mechanism for such difference in relative resistance change further PNC composite tests are being made
Short Term Raw Hide Storing Using Vacuum Preservation Method
No full textIt was investigated a behaviour of hide, which was stored 19 days under vacuum at low temperature, during processing into wet blue. Results of determination of collagen proteins removal when liming, deliming-bating and pickling are presented. The qualitative indexes of wet blue processed under laboratory conditions and of leather produced during industrial trials are presented as well. Such indexes as chromium compounds exhaustion, content of chromium in leather, content of matter soluble in dichloromethane, strength properties, and shrinkage temperature were determined. Obtained results allow supposition that hide under vacuum at low temperature can be stored during 19 days, and this does not cause lowering of leather quality
Properties of Polyurethanes on Tall Oil Fatty Acids Ester Base with Different Types of Flame Retardants
No full text
The Influence of Temperature and Carbon Source on Expression of Recombinant HBcAg
No full textBiotechnological aspects in the field of recombinant
protein production are analysed in this work, which includes
the investigation of factors for the production of virus
like particles (VLPs) formed by recombinant Hepatitis B virus
core-antigen (HBcAg) in inducible bacterial (E. coli) expression
system as well as purification of these particles by gelfiltration
and ion-exchange chromatography. Biomass yield
and VLP production level depended on the cultivation conditions
such carbon source and temperature. As inductor for
protein expression lactose was used
Smart Work (Telework) in Rural Areas: Case Stories from Europe
No full textThe proportion of rural population is decreasing all over Europe and the young and highly-qualified are the first to leave. At the same time the economy is changing toward a more creative conceptual age; routine task are being replaced by creative and flexible activities. According to Richard Florida's three T’s economic growth theory, main drivers of development are technologies, tolerance and the creative class and talent – well educated people dealing with creative or conceptual tasks in their professional life. Although the concept of creative class is most commonly associated with large cities, the nature of creative work allows employees and their tasks to be distributed across settings away from a physical business location (i.e. a central office).
Undoubtedly, the concentration of resources in the agglomerations brings benefits to the economy. At the same time, the information and communication technologies allow reaching the concentration of resources not only physically, but also virtually (digitally). The centrifugal forces play a role, e.g. the rise of the rent of land and such externalities as the noise, pollution, stress etc. For example, since the year 2000 Sweden is experiencing a tendency of young families with children and elderly people moving from cities to rural areas. The main cause behind this life-cycle related migration is high living costs and expensive real estate in cities, proximity to nature, as well as children-friendly social and cultural environment.
Smart work centers, shared office spaces with information and communication technologies that support distant work, have been established in several European countries (United Kingdom, Hungary, Estonia, France etc.) in order to increase economic activity and sustain local populations in rural areas. In some cases smart work centers have been established by the regional and local authorities (e.g. Berwick WorkSpace in United Kingdom and smart work center Nagykáta in Hungary), in some cases by local NGO’s (e.g. Kõnnu and Kolga smart work centers in Estonia). Accordingly they differ significantly in their size. Some of the centers are integrated with business incubation services, some offer training, some child care facilities.
Smart work centers bring benefits to employees, employers, local communities. Employees get the chance to live in a more peaceful, natural environment, decrease their commuting time, achieve a better work-life balance etc. Employers on the other hand can achieve decreased personnel and operating costs and recruit better motivated employees. The local municipalities and communities can achieve an increased perception of the quality of life, advance economic activity and consequently local budget income. Moreover, smart work centers, especially those established as a bottom-up initiative, increase local social capital.
To conclude, smart work contributes to sustaining the rural populations and counterbalancing the concentration of economic activity in the metropolitan areas. However, further research is required in order to offer sustainable solutions for smart work in rural areas
Algorithms for Determination of Safety Intersections
No full textDriver error is the most frequent cause of
accidents. One of the most dangerous places are the
intersections without traffic light regulation. This paper
proposes an algorithm for the safe crossing of such
intersection, based on the processing of information about
location, speed and heading obtained by GPS. The data
exchange is carried out with the help of DSRC
Two-Stage Model of Nanocones Formation on a Surface of Elementary Semiconductors and Their Solid Solutions
No full textA new elaborated laser method for nanocones formation in elementary semiconductors Si and Ge and their solid solutions is reported. A cone possesses unique properties: a small cone is a quantum dot and a long one is a quantum wire with the gradually decreasing diameter from the base till the top of the cone. Everywhere radius of cone is equal or less than Bohr’ radius of electron, exciton or phonon Quantum confinement effect (QCE) takes place. Properties of nanocones using AFM, SEM, photoluminescence (PL) and Raman spectroscopy were studied. Unique visible PL from the surfaces with nanocones was found and is explained by QCE. A “red” shift of Raman spectra in Ge is a good evidence of this suggestion. Asymmetry of PL spectra of the irradiated SiO2/Si structure is explained by formation graded band gap structure due to QCE in nanocones-nanowires with a graded decrease of diameter toward the top of nanocone. Two-stage model of nanocones formation is proposed [1]: Laser Redistribution of Atoms and Selective Laser Annealing. The first stage is characterized by formation of heterostructures such as Ge/Si due to drift of Ge atoms toward the irradiated surface of the sample in the gradient of temperature, the so-called thermogradient effect [2]. New Ge phase is formed at the end of the process. Ge atoms are localized at the surface of Si like a thin film. The second stage is characterized by formation of nanocones on the irradiated surface of a semiconductor by selective laser heating of the top layer with following mechanical plastic deformation of the layer as a result of relaxation of the mechanical compressive stress arising between these layers due to mismatch of their crystal lattices and selective laser heating. It occurs due to higher absorption of the LR by the top layer than the buried layer. For the first time the possibility of graded band gap 1D structure formation in elementary semiconductors was shown.
[1] A. Medvid’. Defects Diffusion Forum, 210, 89 (2002).
[2] A.Medvids, P.Onufrijevs, A.Mychko, Nanoscale Research Letters, 6, 582 (2011)
