Warsaw University of Technology

About: Warsaw University of Technology is a education organization based out in Warsaw, Poland. It is known for research contribution in the topics: Microstructure & Optical fiber. The organization has 14293 authors who have published 34362 publications receiving 492211 citations. The organization is also known as: Warsaw Polytechnic & Politechnika Warszawska.

Battery Management System Based on Battery Nonlinear Dynamics Modeling

Abstract: This paper presents a method of determining electromotive force and battery internal resistance as time functions, which are depicted as functions of state of charge (SOC) because . The model is based on battery discharge and charge characteristics under different constant currents that are tested by a laboratory experiment. This paper further presents the method of determining the battery SOC according to a battery modeling result. The influence of temperature on battery performance is analyzed according to laboratory-tested data, and the theoretical background for calculating the SOC is obtained. The algorithm of battery SOC indication is depicted in detail. The algorithm of the battery SOC ldquoonlinerdquo indication considering the influence of temperature can be easily used in practice by a microprocessor. An NiMH battery is used in this paper to depict the modeling method. In fact, the method can also be used for different types of contemporary batteries, as well as Li-ion batteries, if the required test data are available.

Two-phase reactions in the chemistry of carbanions and halocarbenes. A useful tool in organic synthesis

Abstract: Among numerous base-solvent systems usually applied for the generation of carbanions the two-phase system in which a concentrated aqueous sodium hydroxide solution in the presence of quaternary ammonium compounds acts as the proton acceptor seems to be particularly useful. Under these conditions, C-H acids up to 22 pK a value can be converted into carbanions which exist in the organic phase as ion-pairs with the quaternary ammonium cation. Though the concentration of the carbanions is very low, and does not exceed that of the catalyst, numerous reactions have been successfully performed under these conditions. Thus, alkylation of various C-H acids, such as arylacetonitriles, some esters, ketones, aldehydes, cyclopentadiene hydrocarbons etc. proceeds in this way with higher selectivity and yield as compared to the traditional conditions. The two-phase system is of particular advantage for the generation of trihalomethylanions and dihalocarbenes thereafter, as it allows us to carry out all the reactions typical for these species in the simplest and most effective manner. It is moreover mostly convenient for the reactions of some carbanions with aromatic nitrocompounds (substitution of halogen and nitro group or electron-transfer) which otherwise give rather poor results. And the latest so far recognized application of this system in carbanion chemistry is the reaction of halocarbanions and ylides leading to oxiranes, cyclopropanes and alkenes. The author's point of view is that the first common step of all these reactions, namely proton abstraction with the formation of a carbanion quaternary ammonium cation ion-pair, occurs on the phase boundary. The ion-pair thus formed penetrates inside the organic phase where all subsequent steps (reactions of carbanions with various electrophiles, formation and reactions of halocarbenes etc.) take place.

Transcranial Doppler Pulsatility Index: What it is and What it Isn’t

Abstract: Background Transcranial Doppler (TCD) pulsatility index (PI) has traditionally been interpreted as a descriptor of distal cerebrovascular resistance (CVR). We sought to evaluate the relationship between PI and CVR in situations, where CVR increases (mild hypocapnia) and decreases (plateau waves of intracranial pressure—ICP).

Beam-energy dependence of the directed flow of protons, antiprotons, and pions in Au+Au collisions.

Abstract: Rapidity-odd directed flow (upsilon 1) measurements for charged pions, protons, and antiprotons near midrapidity (y = 0) are reported in root(S)(NN) = 7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeVAu+Au collisions as recorded by the STAR detector at the Relativistic Heavy Ion Collider. At intermediate impact parameters, the proton and net-proton slope parameter d upsilon(1) = d upsilon(1)vertical bar (y=0) shows a minimum between 11.5 and 19.6 GeV. In addition, the net-proton d upsilon(1) = d upsilon(1)vertical bar (y=0) changes sign twice between 7.7 and 39 GeV. The proton and net-proton results qualitatively resemble predictions of a hydrodynamic model with a first-order phase transition from hadronic matter to deconfined matter, and differ from hadronic transport calculations.

Novel space vector based current controllers for PWM-inverters

Abstract: Two novel, simple control strategies for current-controlled pulse-width modulated (PWM) transistor inverters are presented. Both methods are based on the three-level hysteresis comparators which select appropriate inverter output voltage vectors via a switching electrically programmable read-only memory (EPROM) table. The first controller works with current components represented in a stationary coordinate system (AC components) and the second with components represented in a rotated (field-oriented) coordinate system (DC components). The theoretical principles of these methods are discussed. The results of a comparative study, which illustrates the performance of the proposed controller in comparison to the most popular scheme (based on three independent two-level hysteresis comparators), are presented. >