scholarly journals Energetic Efficiency of Vocalization by the Frog Physalaemus Pustulosus

1985 ◽  
Vol 116 (1) ◽  
pp. 47-52 ◽  
Author(s):  
MICHAEL J. RYAN
Keyword(s):  
Lower Limit ◽  
Energy Input ◽  
Acoustic Energy ◽  
Total Power ◽  
Energetic Efficiency ◽  
Physalaemus Pustulosus ◽  
Number Of Components ◽  
Lower Frequencies

1. Male Physalaemus pustulosus consume, on average, 1.2 μl of oxygen in the production of a single call, which is equivalent to an energy input per call of 0.024 J. 2. The total power of complex calls, which can have a varying number of components, ranged from 0.36 to 0.46 mW. The total acoustic energy contained in these complex calls ranged from 0.12 to 0.30mJ. 3. The energetic efficiency of the vocalization ranged from 0.5 to 1.2% which is similar to the range estimated for some other animals. 4. The low energetic efficiency of vocalization by these frogs is due, in part, to the fact that the wavelengths of the call are too long, relative to the size of the frog, to be radiated efficiently. 5. Although shorter wavelengths (higher frequencies) are radiated by the frog at relatively greater intensities, longer wavelengths (lower frequencies) attenuate less rapidly in the environment. It is suggested that selection generated by the acoustics of the environment favours calls with lower frequencies, but the morphology of the animal sets a lower limit to which frequencies can evolve.

scholarly journals Analysis of possibilities and demand for energy in a public building using a tracking photovoltaic installation

2018 ◽  
Vol 49 ◽  
pp. 00096
Author(s):  
Paulina Sawicka-Chudy ◽  
Elżbieta Rybak-Wilusz ◽  
Maciej Sibiński ◽  
Ryszard Pawełek ◽  
Marian Cholewa ◽  
...  
Keyword(s):  
Energy Demand ◽  
Electrical Power ◽  
Power Engineering ◽  
Total Power ◽  
Energetic Efficiency ◽  
Photovoltaic Devices ◽  
Power Networks ◽  
Additional Source ◽  
Public Building ◽  
University Of Technology

In the first part of this paper we present an overview of photovoltaic devices installed in Poland in the years 1960-2015. In the years 2009-2016, approximately 199 MW in total power of photovoltaic devices were installed. The second part of the paper we focus on presenting the research results on the usage of tracking photovoltaic installations in 2010-2016 collected in various periods of their work. PV panels were installed on the building of the Institute of Electrical Power Engineering of the Lodz University of Technology. In this paper we considered PV installations as an additional source of energy improving the total energetic efficiency of the building via the reduction of energy consumed from public electric and power networks. The installation satisfies up to 30% of annual energy demand of laboratories. However, the break-even period of the system was estimated to be about 30 years because of the high cost of installation.

scholarly journals Partially Coherent Backscatter in Radar Observations of Precipitation

2010 ◽  
Vol 67 (6) ◽  
pp. 1928-1946 ◽  
Author(s):  
A. R. Jameson ◽  
A. B. Kostinski
Keyword(s):  
Power Spectrum ◽  
Total Power ◽  
Coherent Scatter ◽  
Incoherent Scatter ◽  
Spectral Peaks ◽  
The Fourier Transform ◽  
Temporal Coherency ◽  
Coherent Backscatter ◽  
Periodic Components ◽  
Lower Frequencies

Abstract Classical radar theory only considers incoherent backscatter from precipitation. Can precipitation generate coherent scatter as well? Until now, the accepted answer has been no, because hydrometeors are distributed sparsely in space (relative to radar wavelength) so that the continuum assumption used to explain coherent scatter in clear air and clouds does not hold. In this work, a theory for a different mechanism is presented. The apparent existence of the proposed mechanism is then illustrated in both rain and snow. A new power spectrum Z( f ), the Fourier transform of the time series of the radar backscattered reflectivities, reveals statistically significant frequencies f of periodic components that cannot be ascribed to incoherent scatter. It is shown that removing those significant fs from Z( f ) at lower frequencies greatly reduces the temporal coherency. These lower frequencies, then, are associated with the increased temporal coherency. It is also shown that these fs are also directly linked to the Doppler spectral peaks through integer multiples of one-half the radar wavelength, characteristic of Bragg scatter. Thus, the enhanced temporal coherency is directly related to the presence of coherent scatter in agreement with theory. Moreover, the normalized backscattered power spectrum Z( f ) permits the estimation of the fractional coherent power contribution to the total power, even for an incoherent radar. Analyses of approximately 26 000 one-second Z( f ) in both rain and snow reveal that the coherent scatter is pervasive in these data. These findings present a challenge to the usual assumption that the scatter of radar waves from precipitation is always incoherent and to interpretations of backscattered power based on this assumption.

scholarly journals Energy Intensity and Productivity in Relation to Agriculture-Bangladesh Perspective

1970 ◽  
Vol 34 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Shaikh Khosruzzaman ◽  
M Ali Asgar ◽  
KM Rezaur Rahman ◽  
Showkat Akbar
Keyword(s):  
Total Energy ◽  
Energy Input ◽  
Energy Intensity ◽  
Agricultural Land ◽  
Total Output ◽  
Energetic Efficiency ◽  
Input Energy ◽  
Weight Factor ◽  
Academy Of Sciences ◽  
Commercial Energy

Results of the energy intensity and overall energetic efficiency show that total energy outputincreased from 69.87 to 82.08 GJha-1, with increasing commercial energy input from 17.94 to 27.10GJha-1 during 1990 to 2005. The corresponding increase in energy intensity was 45.67 to 54.47MJ/US$(2000). Energetic efficiency, calculated as the ratio of total output to input for differentcrops, using weight factor, decreased from 3.97 to 3.03. The energetic efficiency declines withincreasing energy input, and the result indicates that input energy increases faster compared toenergy output. The mechanization index increased from 64 to 78%. However, the main goal beingmaximization of the output per unit agricultural land, the estimated change in efficiency withincreasing input can play an important role in choosing the appropriate input for optimum output.Key words: Energy intensity; Productivity; AgricultureDOI: 10.3329/jbas.v34i1.5492Journal of Bangladesh Academy of Sciences, Vol.34, No.1, 59-70, 2010

Supernovae and interstellar gas dynamics

1967 ◽  
Vol 31 ◽  
pp. 117-119
Author(s):  
F. D. Kahn ◽  
L. Woltjer
Keyword(s):  
Lower Limit ◽  
High Velocity ◽  
Gas Dynamics ◽  
Interstellar Cloud ◽  
Interstellar Gas ◽  
Random Motions ◽  
Relativistic Particles

The efficiency of the transfer of energy from supernovae into interstellar cloud motions is investigated. A lower limit of about 0·002 is obtained, but values near 0·01 are more likely. Taking all uncertainties in the theory and observations into account, the energy per supernova, in the form of relativistic particles or high-velocity matter, needed to maintain the random motions in the interstellar gas is estimated as 1051·4±1ergs.

Factor XII Determinations in the Presence and Absence of Phospholipid Antibodies

1998 ◽  
Vol 79 (01) ◽  
pp. 87-90 ◽  
Author(s):  
D. W. Jones ◽  
M. Winter ◽  
M. J. Gallimore
Keyword(s):  
Lower Limit ◽  
Lupus Anticoagulant ◽  
Factor Xii ◽  
Chromogenic Substrate ◽  
Plasma Samples ◽  
Presence And Absence ◽  
Lower Limit Of Normal

SummaryFactor XII (FXII) levels were determined in plasma samples from 29 normal donors, 10 patients with inherited FXII deficiency (all lupus anticoagulant [LA] negative) and 67 LA positive patients, using clotting (FXIIct), chromogenic substrate (FXIIcs) and immunochemical (FXIIag) assays. Excellent correlations were obtained in the three FXII assays with the LA negative samples and between the FXIIcs and FXIIag assays in the LA positive samples. Correlations between both the FXIIcs and FXIIag with FXIIct in the LA positive patients were poor. Of 67 LA positive samples studied, 25 (37.3%) showed lower values in the FXIIct assay; 13 (19.4%) of these patients were pseudo FXII deficient with values of FXII below the lower limit of normal.These results indicate that a diagnosis of FXII deficiency can be made inappropriately in the presence of phospholipid antibodies and that such a diagnosis should not be made by FXIIct assay alone.

Effects of Age and Health on the Euthyroid Reference Ranges for Serum Free Thyroxine and Free Triiodothyronine

1985 ◽  
Vol 24 (02) ◽  
pp. 57-65 ◽  
Author(s):  
J. E. M. Midgley ◽  
K. R. Gruner
Keyword(s):  
Lower Limit ◽  
Healthy Subjects ◽  
Thyroid Dysfunction ◽  
Reference Range ◽  
Free Thyroxine ◽  
Reference Ranges ◽  
Free Triiodothyronine ◽  
Serum Free ◽  
Young Subjects ◽  
Age Range

SummaryAge-related trends in serum free thyroxine (FT4) and free triiodothyronine (FT3) concentrations were measured in 7248 euthyroid subjects (age-range 3 months to 106 years). 5700 were patients referred to hospitals for investigation of suspected thyroid dysfunction, but who were diagnosed euthyroid. 1548 were healthy blood donors (age-range 18-63 years) with no indication of thyroid dysfunction. FT4 concentrations were little affected by the age, the sex or the state of health of the subjects in either group. Serum FT3 concentrations were significantly affected by both age and health factors. The upper limit of the euthyroid reference range for young subjects up to 15 years was about 20% higher (10.4 pmol/1) than for adult subjects older than 25 years (8.8 pmol/1). The change in the upper limits typical of young subjects to that typical of adults occurred steadily over the decade 15–25 years. After this age, little further change occurred, especially in healthy subjects. Additionally, the lower limit of the euthyroid range for FT3 was extended by the inclusion in the reference group of patients referred to hospitals. Compared with the lower limit of the FT3 range for healthy subjects (5 pmol/1), the corresponding limit for referred subjects (young or adult) was 3.5–3.8 pmol/1. Broadening of the FT3 reference range was probably brought about by a significant number of patients in the hospital-referred group with the “1OW-T3 syndrome” of mild non-thyroidal illness. Accordingly, FT3 was inferior to FT4 in the discrimination of hypothyroidism, as FT4 was unaffected by this phenomenon. Effects of age and non-thyroidal illness on serum FT3 concentrations require great care when selecting subjects for a laboratory euthyroid reference range typical of the routine workload. Constraints on the choice of subjects for FT4 reference ranges are less stringent.

Lower Limit of the Possible Nucleate Pool-Boiling Enhancement by Surfactant Addition to Water

2002 ◽  
Vol 9 (3-4) ◽  
pp. 153-160 ◽  
Author(s):  
Yu-Min Yang ◽  
Chao-Yang Lin ◽  
Ming-Huei Liu ◽  
Jer-Ru Maa
Keyword(s):  
Lower Limit ◽  
Pool Boiling ◽  
Nucleate Pool Boiling ◽  
Boiling Enhancement
Sign in / Sign up

Export Citation Format

Share Document