1,687 research outputs found
An improved two-motor three-phase drive using FCS-MPC based flux and torque control with voltage constraint consideration
No full textThis paper presents a flux and torque control scheme, based on finite-control-set model predictive control (FCS-MPC), for two three-phase induction motors supplied by a five-leg two-level inverter. The reduced-switch-count topology with leg sharing inherently imposes an additional constraint on the voltages in the system. In the best available PWM-based control scheme for this topology, the constraint means that, in simple terms, the sum of speeds of two machines cannot exceed the rated speed of one machine, in order to avoid over-modulation and large torque oscillations. In essence, no provision exists to account for the additional voltage limit of the topology. It will be shown here that the FCS-MPC can consider the voltage constraint dynamically in the control loop, and hence, apart from preserving the independent control of the two machines, it can significantly widen the speed operating range. Three different cost functions, corresponding to three operating modes, are considered. The unique way in which the MPC handles tracking errors allows the motors to operate dynamically in the base speed region with field weakening, without requiring any external change of the flux references. Simulation and preliminary experimental results verify the theory
Rethinking Eurasianism: the Eurasian Union Project of N.A. Nazarbaev
No full textThe article is dedicated to the analysis of basic patterns of the Eurasian Union Project of N.A. Nazarbaev. The author explains the reasons determined absence of interest from the direction of Russian leaders and governments of other CIS’s countries to the initiative of Kazakhstan President in 1990’s and the renewal of Eurasianism in 2000’s. The author also emphasizes the factors defining a special role of Kazakhstan in the processes of integration on the area of Eurasia
Effects of filler calcination on structure and dielectric properties of polyethylene/silica nanocomposites
No full textThis paper reports on an investigation of the effects of calcination on the structure and dielectric properties of polyethylene/silica (SiO2) nanocomposites. Calcination temperatures of 600 and 900 °C have been used in order to modify the surface chemistry and surface structure of the SiO2. The results show that, after calcination, the concentration of surface hydroxyl groups and water molecules around SiO2 and within resulting nanocomposites is reduced. The real permittivity of nanocomposites containing calcined SiO2 decreases compared to nanocomposites based on uncalcined SiO2. The DC breakdown strength of nanocomposites containing calcined SiO2 becomes higher than those containing uncalcined SiO2. In contrast, AC breakdown was found not to be significantly affected by addition of any of the silicas considered here. The use of calcined nanofillers can have positive effects akin to the use of chemically functionalized nanofillers in enhancing the dielectric properties of nanocomposites; both approaches remove polar surface hydroxyl groups.</p
Acacia honey lime ice cream: physicochemical and sensory characterization as effected by different hydrocolloids
No full textWork schedules, wages, and employment in a general equilibrium model with team production
Get PDFAn analysis of working hours, wages, and employment when production requires coordinating the work schedules of heterogeneous workers. The author shows that this coordination aspect of production can have important policy implications.Hours of labor ; Employment (Economic theory) ; Wages
Environmental impacts during the operational phase of residential buildings
No full textTo date, the focus in the field of sustainable building has been on new building design. However, existing residential buildings inflict great environmental burden through three causes: continuous energy consumption, regular building maintenance and replacements. This publication analyses and compares these three causes of environmental burden and shows that material resources needed for replacements generally have a limited potential to reduce environmental impact. Reducing energy consumption for climate control and electrical appliances is much more effective. According to the author, sustainable measures should be tested for shifts in the kind of environmental impact caused due to the use of alternative types of energy resources and altered material quantities. The sustainability of the electricity supply is essential to decrease the total environmental impact of the residential building stock.Sustainable and Healthy HousingOTB Research Institut
Animal Blood Sacrifice in Left-Hand Path and Satanic Milieu: Case Study of the Author N.A-A.218
No full textKrvavá zvířecí oběť v Left-Hand Path a satanském milieu: Případová studie autora N.A-A.218 Matouš Mokrý English Abstract: The main aim of this paper was to study the meaning and nature of Chaos-gnostic animal sacrifice in the texts of N.A-A.218, to describe its social functions and to put it in its social and discoursive context, and thus to provide further understanding of its occurrence within the Left-Hand Path and satanic milieu whose dominant actors have rejected the act of animal sacrifice. The work deals in more detail mainly with discourses found in the texts of N.A- A.218 which are expressing the conception of sacrificial blood as magically potent substance constituting the seat of animal's life; do ut des principle; traditionality and duty of animal sacrifice and the conception of sacrifice as gradual killing of one's own ego which constitutes the part of a Chaos-gnostic's personality that is tying him to the demiurgic material world and its society. Whereas the discourses of blood as a magically potent substance and do ut des principle harmonize the Chaos-gnostic animal sacrifice with intuitive conceptions arising in connection with animal sacrifice across individual human cultures, the discourse of compulsory tradition shapes animal sacrifice as a tool of building, maintaining and control of..
Characteristics of included studies, arranged by author and year.
No full text<p>WM = wire myograph, PM = pressure myograph, PPM = pressure-perfusion myograph, WOP = whole organ perfusion, IV = <i>in vivo</i>. n.a. = not applicable.</p>#<p>data received by email.</p><p>Characteristics of included studies, arranged by author and year.</p
Outsourcing and Skill Imports: Foreign High-Skilled Workers on H-1B and L-1 Visas in the United States
Get PDFThis working paper looks in detail at the H-1B and L-1 visa programs for temporary employment in the United States. Based on official data from the US Citizenship and Immigration Services and the US Department of State, H-1B and L-1 visa issuance rapidly increased in the late 1990s, followed by a marked slowdown after 2001. This points to the highly cyclical nature of both visa programs. Indian nationals and immigrants working in computer-related occupations dominate the H1-B and L-1 population in the United States, but these two groups are also found to be the most cyclical segment, with very large declines in inflows after 2001. The total population of H-1B visaholders in 2003 is estimated to range between 387,000 and 746,000, of which 160,000 to 306,000 were Indian nationals. As all data on H-1B/L-1 visaholders are gross numbers and gross jobs data for comparable categories are absent, the extent of the impact of these visa programs on the US labor market cannot be gauged precisely. A broad range of US industries and educational institutions are found to be employing H-1B recipients, with the IT industry being the dominant sector. Evidence of aggressive wage-cost cutting, including paying H-1B recipients only the legally mandated 95 percent of the prevailing US wage, is found among some H-1B employers, although no systematic abuse of the system is present.Outsourcing, offshoring, high-skilled labor, immigration, H1B/L-1 visas
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