5,685 research outputs found
Classe sociale e fecondità: conta più la classe “di lei” o “di lui”?
No full textLa decisione di avere un figlio è stata spesso studiata in relazione
alla condizione socio-economica della coppia, in termini specialmente di istruzione e ricchezza. Poco considerato è invece il ruolo della
classe sociale individuale dei due membri della coppia. Marco Albertini,
Teodora Maksimovic, Letizia Mencarini e Giorgio Piccitto, per mezzo
di un approccio quantitativo, mostrano che la classe sociale “di lei” è
determinante nella scelta di avere un figlio, e che questa circostanza è più
probabile per le donne in cima alla ‘piramide sociale’
"Spring poem" by Desanka Maksimovic. Harmony of sounding and meaning
No full textThe author makes an attempt to observe and evaluate the expressive performance of the artistic text, to apply a linguo-stylistic analysis as an integral part of every interpretative stream of literary work. The article discusses the role and importance of prosodic elements and analyzes the basic stylistic components of the artistic text: composition, forms of narratives, stylistic figures. Such methods could not be applied as isolated and by themselves, but they are intended to examine the complex structure of Spring Poem by Desanka Maksimovic as a whol
Potential applications of nanometerials in the aviation industry: a review; International Conference of Experimental and Numerical Investigations and NewTechnologies
No full textJ. Bosnjakovic, D. Pavlovic, I. Vasovic Maksimovic; Potential applications of nanometerials in the aviation industry: a review; International Conference of Experimental and Numerical Investigations and NewTechnologies; Zlatibor, Serbia, 29 Jun- 02 July 2021; Serbia; The book of Abstracts; ISBN: 978-86-6060-077-8; pp. 98; 2021
"Spring poem" by Desanka Maksimovic. Harmony of sounding and meaning
No full textThe author makes an attempt to observe and evaluate the expressive performance of the artistic text, to apply a linguo-stylistic analysis as an integral part of every interpretative stream of literary work. The article discusses the role and importance of prosodic elements and analyzes the basic stylistic components of the artistic text: composition, forms of narratives, stylistic figures. Such methods could not be applied as isolated and by themselves, but they are intended to examine the complex structure of Spring Poem by Desanka Maksimovic as a whol
A Digital Pulse-Width Modulator for Phase-Shift Operation of Full-Bridge Isolated DC-DC Converters
No full textThis paper presents the concept, implementation
and testing of a digital pulse-width modulator for phase-shift
driving of full-bridge isolated DC-DC converters. The
proposed phase-shift digital modulator employs a hybrid
counter/delay line structure in order to achieve a 1.25 ns
phase-shift resolution with a switching frequency of about
400 kHz on the secondary side, using a clock frequency of
25 MHz. Provisions for programmable dead times for
switching of the bridge legs are included. The modulator is
tested as a part of a digital controller for a full-bridge DC-DC
isolated converter supplied from a 320 V DC bus with a 20 V-
180 V, 2 A programmable output
Robust Relay-Feedback Based Autotuning For DC-DC Converters
No full textThis paper addresses the design and practical
implementation of a digital controller for switched-mode DCDC
converters with self-tuning capabilities. The proposed
tuning technique is based on digital relay feedback and exhibits
some features specifically developed to improve accuracy and
robustness in practical applications. The most relevant
property is the elimination of the measurement of the output
voltage oscillation amplitude, which is critical from the
accuracy point of view, if the oscillation amplitude is only a few
Least Significant Bits (LSBs) of the A/D converter. The
proposed tuning technique is presented and the complexity of
the resulting algorithm is further analyzed, its performances
compared to other recently proposed tuning techniques. The
described approach is simple, quite accurate, and robust.
Experimental results on a 10 A, 1.5 V point-of-load converter
are provided to show the effectiveness of the discussed
approach
A multiphase model for concrete: numerical solutions and applications
No full textA mathematical and numerical model to predict the non-linear behaviour of concrete as multiphase
porous material is proposed. The model can be usefully applied to several practical cases: evaluation of
concrete performance in the high temperature range, e.g. during fire, to early stages of maturing of massive
concrete structures, to shotcrete in tunnelling, and to durability. All the important phase changes of water and
chemical reactions, i.e. adsorption-desorption, condensation-evaporation, and hydration-dehydration, as well as
the related heat and mass sources or sinks are considered. Changes of the material properties caused by
temperature and pressure changes, concrete damage or carbonation, fresh concrete hardening, as well as
coupling between thermal, hygral and mechanical phenomena are taken into account. This model further allows
to incorporate sorption hysteresis. Some relevant applications of the model will be shown in this work
Sigma-Delta Modulated Digitally Controlled Non-Inverting Buck-Boost Converter for WCDMA RF Power Amplifiers
No full textThis paper focuses on the non-inverting buckboost
converter supplying an adjustable DC voltage to a
WCDMA RF power amplifier (RFPA) in order to improve the
system efficiency under different transmitted RF power levels.
It is shown that precise output voltage positioning and low
output voltage ripple over a wide output voltage range,
including buck, boost and buck/boost transition modes, can be
accomplished using 1_-A modulation in combination with a
small, low-power, low-resolution DPWM core. A two-mode
digital controller is presented, in which the compensator
parameters are changed upon buck/boost mode transitions in
order to improve closed-loop dynamic performance. Results
are verified on an experimental test bed that consists of a
prototype 0.5 Fun CMOS chip that integrates power MOSFETs,
drivers and dead-time control logic, and the digital controller
implemented on an FPGA. The worst case output voltage
ripple over buck, boost and mode transition region is within
35mV and the output voltage transients meet the WCDMA
RFPA settling time requirements
Sensorless Current Sharing in Digitally Controlled Two-Phase Buck DC-DC Converters
No full textThis paper describes a current sharing technique
for digitally controlled two-phase buck DC-DC converters where
pulse width and resistance mismatches are digitally compensated
to achieve approximately equal current sharing without sensing
currents. Effects of various non-idealities on the current sharing
performance are discussed and corresponding mitigation
techniques are presented. An extension to converters with more
than two phases is discussed. Experimental results are shown for
a two-phase synchronous buck converter with 6V input voltage,
and 1.3 V, 0 − 20 A output
Accurate Mode Boundary Detection in Digitally Controlled Boost Power Factor Correction Rectifiers
No full textThis paper presents an accurate mode boundary
detection technique for digitally controlled boost power factor
correction (PFC) rectifiers. Auto-tuning of the current and
voltage control loops as well as estimation of power-stage
parameters L and C are accomplished using sinusoidal
perturbations injected into the control loops. The estimated L
value acquired by this perturbation based tuning process is used
to improve the detection of the boundary between continuous
conduction mode (CCM) and discontinuous conduction mode
(DCM) in the presence of inductance tolerance, thereby
minimizing the mode transition effects and reducing the input
current harmonic distortion. The proposed approach is verified
by experimental results on a 300 W digitally controlled boost PFC
rectifier prototype
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