Average Energy Input Research Articles

Sequences that maximize the symmetric capacity under the requirement of quasi-scalability

We examine the symmetric capacity of quasi-scalable systems under the equal average input energy constraint. It turns out that the maximum achievable symmetric capacity is equal to the maximum achievable sum capacity. Moreover, the multiple-OCDMA signature sets, which are known to maximize the sum capacity under the constraint of quasi-scalability, actually achieve this maximum symmetric capacity.

Corotating solar wind streams and recurrent geomagnetic activity: A review

Solar wind fast streams emanating from solar coronal holes cause recurrent, moderate intensity geomagnetic activity at Earth. Intense magnetic field regions called Corotating Interaction Regions or CIRs are created by the interaction of fast streams with upstream slow streams. Because of the highly oscillatory nature of the GSM magnetic field z component within CIRs, the resultant magnetic storms are typically only weak to moderate in intensity. CIR‐generated magnetic storm main phases of intensity Dst < −100 nT (major storms) are rare. The elongated storm “recovery” phases which are characterized by continuous AE activity that can last for up to 27 days (a solar rotation) are caused by nonlinear Alfven waves within the high streams proper. Magnetic reconnection associated with the southward (GSM) components of the Alfvén waves is the solar wind energy transfer mechanism. The acceleration of relativistic electrons occurs during these magnetic storm “recovery” phases. The magnetic reconnection associated with the Alfvén waves cause continuous, shallow injections of plasma sheet plasma into the magnetosphere. The asymmetric plasma is unstable to wave (chorus and other modes) growth, a feature central to many theories of electron acceleration. It is noted that the continuous AE activity is not a series of substorm expansion phases. Arguments are also presented why these AE activity intervals are not convection bays. The auroras during these continuous AE activity intervals are less intense than substorm auroras and are global (both dayside and nightside) in nature. Owing to the continuous nature of this activity, it is possible that there is greater average energy input into the magnetosphere/ionosphere system during far declining phases of the solar cycle compared with those during solar maximum. The discontinuities and magnetic decreases (MDs) associated with interplanetary Alfven waves may be important for geomagnetic activity. In conclusion, it will be shown that geomagnetic storms associated with high‐speed streams/CIRs will have the same initial, main, and “recovery” phases as those associated with ICME‐related magnetic storms but that the interplanetary causes are considerably different.

New Bounds on the Capacity of Certain Infinite-Dimensional Additive Non-Gaussian Channels

An additive non-Gaussian noise channel with a generalized average input energy constraint is considered. New bounds on the channel capacity are found for the case that the divergence of the probability measure induced in function space by the noise process, with respect to the measure induced by the Gaussian process with the same covariance as that of the noise process, is finite. Upper and lower bounds that depend on the noise process only via the divergence are given for large signal-to-noise energy ratio S. It is also shown that the increase in the capacity of an infinite-dimensional non-Gaussian channel, relative to the infinite-dimensional Gaussian channel capacity S/2, could be significant

Synthesis and cladding of Al 2O 3 ceramic coatings on steel substrates by a laser controlled thermite reaction

After being adequately diluted through the addition of Ni and SiO 2, the thermite reaction can be used to clad an Al 2O 3 based ceramic coating on a steel substrate by laser controlled reactive synthesis with a lower energy input. The dilution rate is the key factor influencing the cladding process. Only when the dilution rate is adequate, the reaction becomes less explosive and a continuous and smooth clad can be obtained. Reasonable addition of diluents and additives should guarantee the adiabatic temperature of the reaction to be lower than 1800 K. The laser energy input is another factor influencing the cladding process. With the rise of the average laser energy input, the width of the final clad and mixing rate of substrate to the clad increase. The addition of additives, especially SiO 2 make a great contribution to the improvement of the clad quality. In this case, the clad is continuous, homogeneous, with few defects and metallurgical bonding to the substrate.

PDA Measurement of Drop Size Distribution for Liquid-Liquid Dispersing in Agitated Tanks

The dispersion characteristics of different axial- and radial-flow impellers at the same average specific power and energy input are investigated in this paper. The impact of turbulent shear stresses is decisive for the breakup of deformable particles like droplets, since dispersion usually is carried out under turbulent flow conditions.

The Influence of Macroscopic Elongational Flow on Dispersion Processes in Agitated Tanks

The influence of elongational and shear gradients in the macroscopic flow field in agitated tanks on dispersion processes is investigated. Measurements of droplet size distribution for a liquid-liquid dispersion process using phase-Doppler anemometry (PDA) reveal that axial-flow impellers, such as the 24°-pitched-blade turbine and propeller, produce smaller droplets than the Rushton turbine at the same average specific power and energy input. These results stand in contradiction to the usual assumption that only the maximum turbulent shear stress determines the breakup process and the Rushton turbine is well known to produce higher turbulent shear stresses. Particle image velocimetry (PIV) measurements of the macroscopic flow field indicate that the 24°-pitched-blade turbine and propeller produce larger areas with higher elongational gradients. Therefore, the proposed consideration of particle breakup due to macroscopic elongational flow in addition to turbulent stresses improves the understanding of dispersion processes in agitated tanks.

Nutritional status and food intake in adolescents living in Western Europe.

This review covers surveys of nutritional intake in adolescents living in several countries of Western Europe. Current definitions of nutritional status are discussed, with a special emphasis on adolescent years. It is generally observed that obesity rates are increasing (especially those of massive obesity) in young people, whereas declared energy intakes are decreasing. Average daily energy input seems adequate in adolescents of Western Europe. However, fat (especially saturated) intake is high while that of CHO and fiber is low. Proteins are mainly (two-thirds) from animal sources. Average micronutrient intakes correspond to recommended values in most cases, but there are a few exceptions (calcium and iron) that are low, particularly in girls. Specific problems become frequent at adolescence, such as dieting, smoking, getting low quality foods away from the home, etc. These behaviors may induce adverse nutritional conditions. On average, nutritional problems at adolescence do not appear to be more severe than at other ages, however they may exert a strong deleterious impact on future health.

Transmitter optimization for noisy ISI channels in the presence of crosstalk

Transmitter optimization techniques for maximizing the throughput of linear ISI channels impaired by additive-Gaussian noise and crosstalk are presented. The transmitter ends of both single carrier and multicarrier transceiver structures are optimized subject to a fixed average input energy constraint. The effect of transmitter optimization on channel throughput is quantified by comparison with scenarios where both the desired user and the crosstalker use a flat energy distribution across the transmission bandwidth.

Throughput-maximizing FIR transmit filters for linear dispersive channels

Optimum finite-impulse response transmit filters for symbol-by-symbol transmission on linear dispersive additive Gaussian noise channels are derived by maximizing the channel throughput, subject to a fixed average input energy constraint. This maximized throughput is compared to that achievable with water-pour and flat transmit filters. The effect of transmit filter optimization on the receiver performance is investigated by considering the popular minimum mean-square error decision-feedback equalizer receiver structure.

Effects of tillage systems on energy and carbon balance in north-eastern Italy

An energy analysis of three cropping systems with different intensities of soil tillage (conventional tillage, CT; ridge tillage, RT; no tillage, NT) was done in a loamy-silt soil (fulvi-calcaric Cambisol) at Legnaro, NE Italy (45°21′N, 11°58′E, 8 m above sea-level (a.s.l.), average rainfall 822 mm, average temperature 11.7°C). This and measurements of the evolution of the organic matter content in the soil also allowed the consequences to be evaluated in terms of CO 2 emissions. The weighted average energy input per hectare was directly proportional to tillage intensity (CT > RT > NT). Compared with CT, total energy savings per hectare were 10% with RT and 32% with NT. Average energy costs per unit production were fairly similar (between 4.5 and 5 MJ kg −1), with differences of 11%. The energy outputs per unit area were highest in CT for all crops, and lowest in NT. The RT outputs were on average more similar to CT (−12%). The output/input ratio tended to increase when soil tillage operations were reduced, and was 4.09, 4.18 and 4.57 for CT, RT and NT, respectively. As a consequence of fewer mechanical operations and a greater working capacity of the machines, there was lower fuel consumption and a consistently higher organic matter content in the soil with the conservation tillage methods. These two effects result in less CO 2 emission into the atmosphere (at 0°C and pressure of 101.3–103 kPa) with respect to CT, of 1190 m 3 ha −1 year −1 in RT and 1553 m 3 ha −1 year −1 in NT. However, the effect owing to carbon sequestration as organic matter will decline to zero over a period of years.

The efficiency of casein N utilization in dairy cows

Eight Friesian dairy cows, two in early, two in mid and two in late lactation and two in the dry period, was maintained by total intragastric nutrition. The average energy input from volatile fatty acids plus casein was 935 kJ kg −1 W 0.75 day −1 for lactating cows and 638 kJ kg −1 W 0.75 day −1 for dry cows. The efficiency of utilization of the nitrogen (N) of the test protein, casein, was established under N-limiting conditions from the regression of productive N (milk N plus retained N) on N input. Daily N inputs (g N kg −1 W 0.75 day −1) ranged from 1.15 to 1.81 in early lactation, from 0.45 to 0.95 in mid lactation, from 0.68 to 1.40 in late lactation and from 0.30 to 0.60 in the dry period. The efficiency of N utilization was 0.693, 0.683, 0.583 and 0.607 for early, mid and late lactation and the dry period, respectively. The slopes of these relationships did not differ significantly, indicating that under N-limiting conditions, the efficiency of N utilization was not affected by the stage of lactation. The overall efficiency with which casein N was converted to milk N and tissue N was 0.66.

Electron precipitation bursts in the nighttime slot region measured simultaneously from two satellites

Based on data acquired in 1982 with the Stimulated Emission of Energetic Particles payload on the low‐altitude (170‐280 km) S81‐1 spacecraft and the Space Environment Monitor instrumentation on the NOAA 6 satellite (800–830 km), a study has been made of short‐duration nighttime electron precipitation bursts at L = 2.0–3.5. From 54 passes of each satellite across the slot region simultaneously in time, 21 bursts were observed on the NOAA 6 spacecraft, and 76 on the S81‐1 satellite. Five events, probably associated with lightning, were observed simultaneously from the two spacecraft within 1.2 s, providing a measure of the spatial extent of the bursts. This limited sample indicates that the intensity of precipitation events falls off with width in longitude and L shell but individual events extend as much as 5° in invariant latitude and 43° in longitude. The number of events above a given flux observed in each satellite was found to be approximately inversely proportional to the flux. The time average energy input to the atmosphere over the longitude range 180°E to 360°E at a local time of 2230 directly from short‐duration bursts spanning a wide range of intensity enhancements was estimated to be about 6 × 10−6 ergs/cm² s in the northern hemisphere and about 1.5 × 10−5 ergs/cm² s in the southern hemisphere. In the south, this energy precipitation rate is lower than that from electrons in the drift loss cone by about 2 orders of magnitude. However, on the basis of these data alone we cannot discount weak bursts from being a major contributor to populating the drift loss cone with electrons which ultimately precipitate into the atmosphere.

Electricity and natural gas use for residential space heating: U.S. experience, 1976–1980

Energy consumption for residential space heating has been studied for households using electricity and natural gas, based on aggregate sales data for 1976–1980. The ratio of average end-use energy consumption with electricity to that with natural gas was found to be 0.44 ± 0.06, despite little use of electric heat pumps. Together with the results of other studies, this estimate suggests that electric space heating can be used in future construction without requiring more primary input energy (including generation losses) than the average input energy used for gas space heating in existing residences, assuming modest conservation measures. While these results do not establish the relative fuel consumption in future gas-heated and electrically-heated households, they do provide a rough ceiling on the amount of energy required if electricity is used.

Procedure for diagnosing processes in the discharge chamber of a fast-flow CO2laser

A semiempirical procedure was developed for investigating the discharge-chamber characteristics of a fast-flow CO2 laser. It was found to be sufficient merely to measure the average specific input energy and the gas temperature, averaged over the cross section of the chamber. It was noted that the calculation of the operating efficiency of the discharge chamber was insensitive to a lack of precision in the experimental data.

On the capacity of certain additive non-Gaussian channels

A model of an additive non-Gaussian noise channel with generalized average input energy constraint is considered. The asymptotic channel capacity <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C_{\zeta}(S)</tex> , for large signal-to-noise ratio <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</tex> , is found under certain conditions on the entropy <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H_{ \tilde{ \zeta}}( \zeta)</tex> of the measure induced in function space by the noise process <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\zeta</tex> , relative to the measure induced by <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\tilde{\zeta}</tex> , where is a Gaussian process with the same covariance as that of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\zeta</tex> . If <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H_{ \tilde{zeta}}( \zeta) &lt; \infty</tex> and the channel input signal is of dimension <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M&lt; \infty</tex> , then <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C_{ \zeta}(S)= \frac{1}{2}M \ln(1 + S/M) + Q_{\zeta}( M ) + {o}(1)</tex> , where <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0 \leq Q_{ \zeta}( M ) \leq H_{ \tilde{ \zeta}}( \zeta)</tex> . If the channel input signal is of infinite dimension and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H_{ \tilde{ \zeta}}( \zeta) \rightarrow 0</tex> for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S \rightarrow \infty</tex> , then <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C_{ \zeta}(S) = \frac{1}{2}S+{o}(1)</tex> .

A Note on the Influx of Extraterrestrial Dust as an Energy Source in the E Region

Some connection between sporadic E layer irregularities and incoming extraterrestrial dust at heights of llO km and above has been indicated by the comparison of optical radar and ionosonde data [Fiocco, 1965]. The object of this note is primarily to point out the possible importance of the influx of extraterrestrial dust to the energy balance of the E region. Much independent evidence suggests that the average influx rate on earth of small particles of extraterrestrial origin, ranging in diameter from 0.1 µ to 100 µ, is of the order of 104 tons/day and that peaks of the order of 105 tons/day or even 106 tons/day may be possible. If these estimates are correct, and since the particles enter the earth's atmosphere at speeds of the order of 10 km/s, their influx may represent an average energy input for a vertical column in the E region of the order of 10−2 erg/cm2 sec and as high as 1 erg/cm2 sec. If it were possible to fully convert this energy into ionization, for a column of 10‐km length and a recombination coefficient α = 10−8 cm3 sec−1, electron densities of the order of 105 cm−3 and higher would be achieved, which are in excess of what is needed in a sporadic E layer. While this process may therefore in some cases supply the background ionization necessary for the formation of the layer, and other processes may be operative in organizing the distribution of charge in space, it is possible that the way by which the dust particles dissipate their energy may, by itself, directly lead to the formation of a layer. The energy of small particles characterized by a constant area‐over‐mass ratio would be dissipated in a height interval of a few tens of kilometers, the length of the interval depending upon size and angle of incidence. However, fragmentation in flight of the micrometeoroids due to mechanical, thermal, and electric effects [Fiocco and Colombo, l964] may cause the dissipation to take place in a much shorter interval of altitudes, possibly less than a scale height.