A Kiss 4-difference term from a ternary term

AbstractWe provide more characterizations of varieties with a weak difference term and of neutral varieties. We prove that a variety has a (weak) difference term (is neutral) with respect to the TC-commutator iff it has a (weak) difference term (is neutral) with respect to the linear commutator. We show that a variety V is congruence meet semi-distributive iff V is neutral, iff M3 is not a sublattice of Con A, for A ∈ V, iff there is a positive integer n such that .

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Computationally approximated solution for the equation for Henssge’s time of death estimation

BMC Medical Informatics and Decision Making ◽

10.1186/s12911-019-0920-y ◽

2019 ◽

Vol 19 (1) ◽

Author(s):

Wolf Schweitzer ◽

Michael J. Thali

Keyword(s):

Time Frame ◽

Time Of Death ◽

Death Scene ◽

Ambient Temperatures ◽

Post Mortem Interval ◽

Upper Limits ◽

Double Exponential ◽

Device Applications ◽

Body Cooling ◽

Difference Term

Abstract Background Time of death estimation in humans for the benefit of forensic medicine has been successfully approached by Henssge, who modelled body cooling based on measurements of Marshall and Hoare. Thereby, body and ambient temperatures are measured at the death scene to estimate a time of death based on a number of assumptions, such as initial body temperature and stable ambient temperature. While so far, practical use of the method resorted to paper print outs or copies of a nomogram using a ruler, increasingly, users are interested in computer or mobile device applications. We developed a computational solution that has been available online as a web accessible PHP program since 2005. From that, we have received numerous requests not so much to detail our code but to explain how to efficiently approximate the solution to the Henssge equation. Methods To solve Henssge’s double exponential equation that models physical cooling of a body, it is sufficient to determine a difference term of the equation that will be close to zero for the correct time of death using a discrete set of all sensible possible solutions given that the modelled time frame has practical upper limits. Best post-mortem interval approximation yields minimal difference between equation terms Results The solution is approximated by solving the equation term difference for a discrete set of all possible time of death intervals that are sensibly found, and by then determining the particular time of death where equation term difference is minimal. Conclusions The advantage of a computational model over the nomogram is that the user is also able to model hypothermia and hyperthermia. While mathematically impossible to solve in a straightforward way, solutions to the Henssge equation can be approximated computationally.

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A Characterization of Varieties with a Difference Term

Canadian Mathematical Bulletin ◽

10.4153/cmb-1996-038-0 ◽

1996 ◽

Vol 39 (3) ◽

pp. 308-315 ◽

Cited By ~ 1

Author(s):

Paolo Lipparini

Keyword(s):

Locally Finite ◽

Difference Term ◽

Locally Finite Varieties

AbstractWe characterize, by means of congruence identities, all varieties having a weak difference term, and all neutral varieties. Our characterization of varieties with a difference term is new even in the particular case of locally finite varieties.

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Tracers of air-sea gas exchange

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1988.0045 ◽

1988 ◽

Vol 325 (1583) ◽

pp. 93-103 ◽

Cited By ~ 18

Keyword(s):

Wind Speed ◽

Sea Surface ◽

Eddy Correlation ◽

Radioactive Tracers ◽

Sulphur Hexafluoride ◽

Sea State ◽

Transfer Velocity ◽

Concentration Difference ◽

Interfacial Concentration ◽

Difference Term

The flux of gas across the air-sea interface is determined by the product of the interfacial concentration difference driving the exchange and a rate constant, often termed the transfer velocity. The concentration-difference term is generally obtained by direct measurement, whereas more indirect approaches are required to estimate the transfer velocity and its variation as a function of controlling parameters such as wind and sea state. Radioactive tracers have proved particularly useful in the estimation of air-sea transfer velocities and, recently, stable purposeful tracers have also started to be used. In this paper the use of the following tracers to determine transfer velocities at the sea surface is discussed: natural and bomb-produced 14 C, dissolved oxygen, 222 Rn and sulphur hexafluoride. Other topics covered include the relation between transfer velocity and wind speed as deduced from tracer and wind-tunnel studies, and the discrepancy between transfer velocities determined by using tracers and from eddy correlation measurements in the atmosphere.

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Multiband Radar Signal Coherent Processing Algorithm for Motion Target

International Journal of Antennas and Propagation ◽

10.1155/2017/4060789 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8

Author(s):

Tingjing Wang ◽

Ying Zhang ◽

Hua Zhao ◽

Yanxin Zhang

Keyword(s):

Radar Signal ◽

Quadratic Term ◽

Minimum Entropy ◽

Signal Model ◽

Quadratic Phase ◽

Entropy Principle ◽

Geometrical Theory Of Diffraction ◽

And Performance ◽

Difference Term ◽

Phase Term

In real application, most aerial targets are movable. In this paper, an effective multiple subbands coherent processing method is proposed for moving target. Firstly, an echoed signal model of motion target based on geometrical theory of diffraction is established and the influence of velocity on range profile of the target is analyzed. Secondly, a method based on minimum entropy principle is used to compensate velocity. Then, incoherent factors including a quadratic phase term, a linear phase factor, a fixed factor, and an amplitude difference term are analyzed. Subsequently, efficient methods are applied to estimate other incoherent factors, except that the quadratic term is small enough to be ignored. Finally, the feasibility and performance of the proposed method are investigated through numerical simulation.

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Polynomial Expressions for the Thermal Efficiency of the Parabolic Trough Solar Collector

Applied Sciences ◽

10.3390/app10196901 ◽

2020 ◽

Vol 10 (19) ◽

pp. 6901

Author(s):

Evangelos Bellos ◽

Christos Tzivanidis

Keyword(s):

Thermal Efficiency ◽

Solar Collector ◽

Percentage Error ◽

Parabolic Trough ◽

Degree Polynomial ◽

Unknown Parameters ◽

Fourth Degree ◽

Best Fitting ◽

Difference Term ◽

Parabolic Trough Solar Collector

The parabolic trough solar collector (PTC) is the most mature solar concentrating technology, and this technology is applied in numerous thermal applications. Usually, the thermal efficiency of the PTC is expressed with the aid of polynomial expressions. However, there is not a universal expression that is applied in all cases with high accuracy. Many studies use expressions with the first-degree polynomial, second-degree, or fourth-degree polynomial expressions. In this direction, this work is a study that investigates different expressions about the thermal efficiency of a PTC with a systematic approach. The LS-2 PTC module is examined with a developed numerical model in the Engineering Equation Solver for different operating temperatures and solar beam irradiation levels. This model is validated using experimental literature data. The found data are approximated with various polynomial expressions with up to six unknown parameters in every case. In every case, the mean absolute percentage error and the R2 are calculated. According to the final results, the use of the third power term leads to the best fitting results, as well as the use of the temperature difference term (ΔΤ), something that is new according to the existing literature. More specifically, the final suggested formula has the following format: “ηcol = a0 + a3∙ΔT3/Gb + b∙ΔΤ”. The results of this work can be used by the scientists for the optimum fitting of the PTC efficiency curves and for applying the best formulas in performance determination studies.

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Polynomial-time tests for difference terms in idempotent varieties

International Journal of Algebra and Computation ◽

10.1142/s021819671950036x ◽

2019 ◽

Vol 29 (06) ◽

pp. 927-949

Author(s):

William DeMeo ◽

Ralph Freese ◽

Matthew Valeriote

Keyword(s):

Polynomial Time ◽

Finite Algebra ◽

Finite Language ◽

Difference Term ◽

Practical Question

We consider the following practical question: given a finite algebra [Formula: see text] in a finite language, can we efficiently decide whether the variety generated by [Formula: see text] has a difference term? We answer this question (positively) in the idempotent case and then describe algorithms for constructing difference term operations.

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