50 research outputs found
Monitoring sealed automotive lead-acid batteries by sparse-impedance spectroscopy
A reliable diagnostics of lead-acid batteries would become mandatory with the induction of an improved power net and the increase of electrically assisted features in future automobiles. Sparse-impedance spectroscopic technique described in this paper estimates the internal resistance of sealed automotive lead-acid batteries in the frequency range 10 Hz-10 kHz, usually produced by the alternators fitted in the automobiles. The state-of-health of the battery could be monitored from its internal resistance
A Review on Microalgae Biofuel Production and use in CI Engine Applications
Alternative fuel technology of third-generation biofuels in place of conventional fossil fuels is currently being witnessed at a global level. Due to its sustainability and environmental friendliness, in recent years more importance is being given to biodiesel in CI engine applications. Recent trends show that microalgae are promoted as a bio-fuel due to their inherent advantages of abundant availability of oil sources and faster growth rate with ease of cultivation. Particular species of algae such as Chlorella, Botryococcus braunii, and Scenedesmus obliquus are conventionally favored for biodiesel production as they have a prominent amount of lipids content. This review outlines the current state of experimental investigations on the use of different algae biodiesel blends with diesel for CI engines. Amongst the different algae-based biodiesel, the dual Calophyllum Inophyllum methyl ester blend (CIME20) with DEE demonstrated the maximum brake thermal efficiency (BTE) and better brake-specific fuel consumption (BSFC) of CI engines. In terms of emissions, the CO, UBHC, and smoke levels are significantly lower for algae blends in contrast to neat diesel
Strategies for simulating time evolution of Hamiltonian lattice field theories
Simulating the time evolution of quantum field theories given some
Hamiltonian requires developing algorithms for implementing the unitary
operator e^{-iHt}. A variety of techniques exist that accomplish this task,
with the most common technique used so far being Trotterization, which is a
special case of the application of a product formula. However, other techniques
exist that promise better asymptotic scaling in certain parameters of the
theory being simulated, the most efficient of which are based on the concept of
block encoding.
In this work we study the performance of such algorithms in simulating
lattice field theories. We derive and compare the asymptotic gate complexities
of several commonly used simulation techniques in application to Hamiltonian
Lattice Field Theories. Using the scalar \phi^4 theory as a test, we also
perform numerical studies and compare the gate costs required by Product
Formulas and Signal Processing based techniques to simulate time evolution. For
the latter, we use the the Linear Combination of Unitaries construction
augmented with the Quantum Fourier Transform circuit to switch between the
field and momentum eigenbases, which leads to immediate order-of-magnitude
improvement in the cost of preparing the block encoding.
The paper also includes a pedagogical review of utilized techniques, in
particular Product Formulas, LCU, Qubitization, QSP, as well as a technique we
call HHKL based on its inventors' names.Comment: 33 pages, 2 figures, 8 circuit diagrams, 5 tables. Version submitted
for publicatio
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Block encoding bosons by signal processing
Block Encoding (BE) is a crucial subroutine in many modern quantum algorithms, including those with near-optimal scaling for simulating quantum many-body systems, which often rely on Quantum Signal Processing (QSP). Currently, the primary methods for constructing BEs are the Linear Combination of Unitaries (LCU) and the sparse oracle approach. In this work, we demonstrate that QSP-based techniques, such as Quantum Singular Value Transformation (QSVT) and Quantum Eigenvalue Transformation for Unitary Matrices (QETU), can themselves be efficiently utilized for BE implementation. Specifically, we present several examples of using QSVT and QETU algorithms, along with their combinations, to block encode Hamiltonians for lattice bosons, an essential ingredient in simulations of high-energy physics. We also introduce a straightforward approach to BE based on the exact implementation of Linear Operators Via Exponentiation and LCU (LOVE-LCU). We find that, while using QSVT for BE results in the best asymptotic gate count scaling with the number of qubits per site, LOVE-LCU outperforms all other methods for operators acting on up to ≲11 qubits, highlighting the importance of concrete circuit constructions over mere comparisons of asymptotic scalings. Using LOVE-LCU to implement the BE, we simulate the time evolution of single-site and two-site systems in the lattice φ4 theory using the Generalized QSP algorithm and compare the gate counts to those required for Trotter simulation
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Strategies for simulating the time evolution of Hamiltonian lattice field theories
Simulating the time evolution of quantum field theories given some Hamiltonian H requires developing algorithms for implementing the unitary operator e-iHt. A variety of techniques exist that accomplish this task, with the most common technique used so far being Trotterization, which is a special case of the application of a product formula. However, other techniques exist that promise better asymptotic scaling in certain parameters of the theory being simulated, the most efficient of which are based on the concept of block encoding. In this work we study the performance of such algorithms in simulating lattice field theories. We derive and compare the asymptotic gate complexities of several commonly used simulation techniques in application to Hamiltonian lattice field theories. Using the scalar φ 4 theory as a test, we also perform numerical studies and compare the gate costs required by product formulas and signal-processing-based techniques to simulate time evolution. For the latter, we use the linear combination of unitaries (LCU) construction augmented with the quantum Fourier transform circuit to switch between the field and momentum eigenbases, which leads to immediate order-of-magnitude improvement in the cost of preparing the block encoding. This paper also includes a pedagogical review of the techniques used, in particular product formulas, LCU, qubitization, quantum signal processing, as well as the technique for simulating geometrically-local Hamiltonians developed by Haah, Hastings, Kothari, and Low
Remote Monitoring of the Heart Condition of Athletes by Measuring the Cardiac Action Potential Propagation Time Using a Wireless Sensor Network
Highly performing athletes are susceptible to cardiac damage of several kinds which may be irreversible. The monitoring of heart rate and ECG waveforms from such subjects by wireless sensor networks has been reported in health and sports care documents. However, a more decisive parameter for instant to instant changes would be the time of Cardiac Action Potential Propagation. This time, which can be between 15-20 ms would shoot suddenly in acute stress in highly performing athletes for short durations. Repeated incidents of such rising values will tend to cause irreversible damage to the heart. We developed the technique of measuring this time and reporting it through a wireless sensor network to monitoring station
Racemic epinephrine compared to salbutamol in hospitalized young children with bronchiolitis; a randomized controlled clinical trial [ISRCTN46561076]
BACKGROUND: Bronchiolitis is the most common cause of lower respiratory tract illness in infancy, and hospital admission rates appear to be increasing in Canada and the United States. Inhaled beta agonists offer only modest short-term improvement. Trials of racemic epinephrine have shown conflicting results. We sought to determine if administration of racemic epinephrine during hospital stay for bronchiolitis improved respiratory distress, was safe, and shortened length of stay. METHODS: The study was a randomized, double-blind controlled trial of aerosolized racemic epinephrine compared to salbutamol every one to 4 hours in previously well children aged 6 weeks to ≤ 2 years of age hospitalized with bronchiolitis. The primary outcome was symptom improvement as measured by the Respiratory Distress Assessment Instrument (RDAI); secondary outcomes were length of stay in hospital, adverse events, and report of symptoms by structured parental telephone interview one week after discharge. RESULTS: 62 children with a mean age of 6.4 months were enrolled; 80% of children had Respiratory Syncytial Virus (RSV). Racemic epinephrine resulted in significant improvement in wheezing and the total RDAI score on day 2 and over the entire stay (p < 0.05). The mean LOS in the epinephrine arm was 2.6 days (95% CI 2, 3.2) v. 3.4 days in those in the salbutamol group (95% CI 2.6, 4.2) (p > 0.05). Adverse events were not significantly different in the two arms. At one week post-discharge, over half of parents reported that their child still had a respiratory symptom and 40% had less than normal feeding. CONCLUSION: Racemic epinephrine relieves respiratory distress in hospitalized infants with bronchiolitis and is safe but does not abbreviate hospital stay. Morbidity associated with bronchiolitis as identified by parents persists for at least one week after hospital discharge in most infants
