Levels Of Energy Input Research Articles

Simplified UV-preionized long-pulse TEA CO2-laser amplifier

A simplified UV-preionized long-pulse TEA CO2-laser amplifier is proposed, which is powered by a common Marx generator for both the preionization arc discharges and the main laser discharge. The measurements of small-signal gain reveal that there exists an optimum capacitance for the capacitors which are provided in the preionization circuit for the control of preionization level. The physical interpretation for this is also given. A small-signal gain higher than 3%/cm and an extraction energy of nearly 14 J/l (at the input energy level of nearly 1 J) have been achieved. It has also been demonstrated that the amplifier can amplify a long laser pulse of the order of microseconds without serious distortion of pulse waveform.

A Preliminary Investigation of the Utilization of True Metabolizable Energy by Chicks

The change in carcass composition associated with intake of true metabolizable energy (TME) by young broiler chicks was investigated. The experiment comprised 17 treatments, 16 of which formed a 2 × 4 × 2 factorial design with six replications; the experimental unit was a pen of four male chicks. The factorial treatments consisted of two basal diets (lipogenic and proteogenic), four levels of cellulose dilution (to cause a range of basal diet intakes), and two feeding periods (10 to 17 and 10 to 24 days of age). The birds were fed ad libitum, feed intake was recorded, and final carcass composition was measured. The 17th treatment comprised 24 pens of chicks killed at the start of the experiment to estimate initial carcass composition.The gross energy of carcass fat and protein was estimated by chemical and physical analysis and by regression analysis, the latter yielded estimates of 24.5 and 39.5 MJ/kg for protein and fat, respectively.Basal diet intake was reduced by more than 50% at the highest level of cellulose dilution and increased by about 60% when the feeding period was extended from 17 to 24 days. Pen weight gain and carcass composition were affected by basal diet intake. The energy retained in the carcass (MJ/Wkg.75/day) (RE′) increased in a linear manner with the intake of TME (MJ/Wkg.75/day) (ITME’), the slope of the line being greater for the lipogenic than for the proteogenic diet. Projected back to zero ITME’, the regression lines for pens in positive energy balance gave an estimate of .420 MJ loss, After 7 days on experiment, the energy retained as fat (RE′f) and as protein (RE′p) increased approximately linearly with ITME’, but after 14 days some curvature was apparent, the deposition of protein increasing more rapidly at the lower levels of energy input, and the deposition of fat increasing more rapidly at the higher levels of energy input. The RE′p was only slightly higher on the proteogenic diet than on the lipogenic diet, at the same level of ITME’, but the effect of basal diet on RE′f was considerable. For both diets at RE′ = 0 there was gain in body protein accompanied by loss of body fat.

Effects of photoperiod and level of irradiance on production of haustoria by Erysiphe graminis f.sp. hordei

The production of haustoria by colonies of Erysiphe graminis DC. ex Mérat f.sp. hordei Marchai was studied in detached leaf segments of susceptible spring barley ( Hordeum vulgare L.) incubated for 108 h under various combinations of daylength and irradiance arranged to give comparable levels of energy input. Under all irradiances haustorial production was faster under short (6 h) than long days (18 h). Irradiance had an independent effect on haustorial production, but although 3.77 W/m 2 was optimal under both daylengths, the influence of irradiance level was relatively small compared with that of daylength. Faster haustorial production under short days was associated with greater synchrony in the production of haustorial generations formed subsequent to the primary, but the clearest distinction between secondary and tertiary generation haustoria was obtained with a short day/high irradiance treatment. Although this treatment was not optimal for haustorial production, such incubation conditions aid confident identification of tertiary generation haustoria which allows sensitive measurement of colony size useful for quantifying host resistance of a partial nature.

Preliminary evaluation of energy consumption in China's agriculture — Analysis of two specific cases

The present status and the perspective of the energy consumption in China's agriculture, with emphasis on crop production, was discussed based on nation-wide statistics as well as two specifically investigated production units. It was estimated that about 17.2% of China's commercial energy was consumed in the rural area in 1978. Commercial energy used in crop production was estimated as 7.3% of the energy input of the whole country. Chemical fertilizer has been and will still be, in the near future, the major energy expenditure in China's crop production. In the two investigated units, the energy input level for crop production has reached that of the industrialized countries. The average level of the whole country, however, is still at a relatively low level of about 1.2 × 10 7 kJ/ha. As a first step to modernize China's agriculture, it appears that an additional commercial energy input of 8.7 × 10 14 kJ would be needed. Approaches to solving the energy problems in China's rural area are discussed briefly.

Evaluation of static mixers as convection promoters in the ultrafiltration of dairy liquids

An investigation was made to determine the efficiency of various types of static mixer (variants of the Kenics type) for enhancing the permeate flux in ultrafiltration plants. A theoretical analysis of the transport phenomena that occur in the laminar-flow region in a tube divided into two half-cylindrical channels, showed that the mass transfer coefficient increased by a factor 1.95 as compared with the mass transfer coefficient in a cylindrical tube. The increase in permeate flux obtained in the experiments, however, amounted to a factor 2.9. This extra effect should be attributed to rotation of the liquid and changes in the direction of rotation, caused by the static mixers. It was also found that the effect was intensified at increasing Sc-number and decreasing Re-number. From energy considerations it appeared that, at equal energy input levels, approximately equal permeate fluxes were achieved in both the laminar flow and the turbulent-flow region, whether static mixers were used or not. So it has to be concluded that the types of static mixer tested did hardly improve the energy efficiency in ultrafiltration plants under the prevailing conditions.

NATURAL CONVECTION HEAT TRANSFER IN COVERED PLANT CANOPIES

Abstract A facility has been designed and constructed to carry out the study of free convection from leaves in a covered plant canopy. The system considered is one with long parallel rows of canopies with finite widths, heights and spacings between them. To generate free convective air flow patterns inside the canopies, leaves have been simulated by small electric bulbs. These “bulb canopies” were constructed in such a way so as to provide variable (leaf surface area)/(volume) ratios. The electrical system was designed to provide various levels of energy input at different heights of the canopies which would correspond to desired solar flux absorption at these heights. Convective heat transfer coefficients (in terms of Nusselt numbers) are presented for a leaf area density of approximately 90 cm 2 /1,000 cm 3 . Heat-transfer coefficients were measured on two types of thin plate 8 × 8 cm size, one having both surfaces of copper and the other having both surfaces covered with white paper. The first such plate simulated a leaf with uniform surface temperature and the second a leaf with uniform surface heat flux. These plates were fixed in a vertical position at about the centre of the canopy. From the experimental data, two heat-transfer correlations have been presented for the two plates. The results show that the difference between the values obtained from the two simulated leaves is not greater than about 15%.

Natural convection heat transfer in covered plant canopies

A facility has been designed and constructed to carry out the study of free convection from leaves in a covered plant canopy. The system considered is one with long parallel rows of canopies with finite widths, heights and spacings between them. To generate free convective air flow patterns inside the canopies, leaves have been simulated by small electric bulbs. These “bulb canopies” were constructed in such a way so as to provide variable (leaf surface area)/(volume) ratios. The electrical system was designed to provide various levels of energy input at different heights of the canopies which would correspond to desired solar flux absorption at these heights. Convective heat transfer coefficients (in terms of Nusselt numbers) are presented for a leaf area density of approximately 90 cm 2/1,000 cm 3. Heat-transfer coefficients were measured on two types of thin plate 8 × 8 cm size, one having both surfaces of copper and the other having both surfaces covered with white paper. The first such plate simulated a leaf with uniform surface temperature and the second a leaf with uniform surface heat flux. These plates were fixed in a vertical position at about the centre of the canopy. From the experimental data, two heat-transfer correlations have been presented for the two plates. The results show that the difference between the values obtained from the two simulated leaves is not greater than about 15%.

Kinematically coupled non-linear vibrations

The dynamic response of a simple two-degree-of-freedom mechanical analogue is investigated to illustrate the nature of mode interaction that exists for systems in which the stiffness against vibrations in one mode is sensitive to the amplitude of the vibration response in the second possible mode. A finite difference approximation of the non-linear differential equations controlling the small non-linear interactive dynamics of this model is used to determine the responses for a representative range of non-dimensional parameters. These numerical experiments confirm the phenomenological predictions of an earlier paper: that over a range of excitation energy inputs dependent upon the damping characteristics and the separation between the two uncoupled natural frequencies of small vibration, a multiplicity of resonant frequencies will be observed to occur in the first mode. In some situations and above a certain super-critical energy input level, it becomes impossible to observe the resonance that would be predicted from an uncoupled small vibration analysis of this first mode.

Coupled vibration modes

The dynamic response of a simple two degree-of-freedom mechanical analogue is investigated to illustrate the nature of mode interaction that exists for systems in which the stiffness against vibration in one mode is sensitive to the amplitude of the vibration response in the second possible mode. This model shows that over a range of excitation energy input, dependent upon the damping characteristics and the separation between the two uncoupled natural frequencies of small vibration, a multiplicity of resonant frequencies will be observed to occur in the first mode. In some situations, and above a certain super-critical energy input level, it becomes impossible to observe the resonance that would be predicted from an uncoupled small vibration analysis of this first mode. It is suggested that this phenomenon could be displayed in a more complex manner in the dynamic response of a wide range of shell and shell-like structures.

RELATIONSHIP OF WEIGHTS OF CHEMICAL COMPONENTS AND EMPTY BODY WEIGHT IN YOUNG PIGS

The influence of genotype, sex, frequency of feeding, and plane of nutrition on the relationship between weights of chemically determined components in the empty bodies and the empty body weight was estimated by the use of simple linear regression analyses. The data used were body composition from three experiments involving 107 pigs belonging to Lacombe, Yorkshire, Lacombe × Yorkshire, and Hampshire × Yorkshire breeds representing both sexes and fed at levels of dietary energy inputs varying from 120 to 340 kcal ME/W0.75kg daily. All experiments consisted of a feeding trial and a comparative slaughter analysis. Within a range of 5-35 kg of empty body weight (EBW) the rate of increase in the water, protein, fat, and ash components in the empty body was a linear function of the increase in EBW. The rate of increase in weights of chemical components as a percentage of increase in EBW was: water 60.9; protein 16.3; fat 20.2; and ash 2.7. These estimates were similar for pigs of different breeds and whether fed two or five times daily. The rate of accretion of water per unit increase in EBW was greater in male than in female pigs. Plane of nutrition ranging from 220 to 340 kcal ME/W0.75kg daily did not affect the rate of deposition of water, protein, fat, or ash components per unit increase in EBW. Pigs fed at the maintenance level of feeding (120–140 kcal ME/W0.75kg daily) had a greater rate (P < 0.05) of accretion of water per unit increase in EBW as compared with pigs fed 320–340 kcal ME/W0.75kg per day. The rate of accretion of ash per unit increase in EBW in pigs fed 120–140 kcal ME/W0.75kg per day was greater (P < 0.05) than for pigs fed 220–240 kcal ME/W0.75kg per day. The rate of change in the protein and fat components remained constant. The results are discussed in relation to the concept of mass-related homeostasis.

Thermal Transient Effects in Repetitively Pulsed Flashlamp-Pumped YAG:Nd and YAG:Nd,Lu Laser Material

Measurements have been made of the change of the optical pathlength due tothermal transient effects of two laser rod materials: YAG:Nd and YAG:Nd, Lu. These optical distortion measurements were studied as a function of flashlamp input energy level, coolant temperature, and pulse repetition frequency. Experimental data were obtained by passing a collimated He-Ne probe beam through the flashlamp pumped laser rod and recording the detector output as a function of time. The data show a significant difference between YAG:Nd and Lu co-doped YAG:Nd with respect to thermal transient effects. Using existing theory, results of calculations that predict the thermal effects are also presented for comparison with the experimental observations.

EFFECTS OF FREQUENCY OF FEEDING ON ENERGY METABOLISM AND BODY COMPOSITION OF YOUNG PIGS

The influence of frequency of feeding on the coefficient of digestibility and metabolizability of dietary energy, fasting heat production, maintenance energy requirements, efficiency of utilization of metabolizable energy (ME) for maintenance and growth, net energy value of diet, rate of lipogenesis in adipose tissue, and the body composition of young pigs was investigated. A total of 40 pigs was used in this study, of which four constituted the initial slaughter group. The remaining 36 pigs were allotted to a feeding experiment of a randomized complete-block design involving a 3 × 2 factorial arrangement (level of dietary energy inputs: 140, 240, and 340 kcal ME/W0.75kg daily; and feeding frequency: two and five times daily). One metabolism experiment was conducted during the 3rd wk of the 37-day feeding experiment. Subcutaneous adipose tissue slices taken immediately after electrocution of 24 pigs were used to determine the rate of lipogenesis as indicated by the metabolism of glucose-U-14C. Frequency of feeding had no effect on the digestible energy, ME, and NEm value of the diet or the efficiency of utilization of ME for maintenance. However, frequent feeding increased the fasting heat production, metabolizable energy requirement for maintenance, net efficiency of utilization of metabolizable energy for production and the NEg value of the diet. Frequency of feeding did not produce any change in the weights of empty stomach or small intestine. Although the rate of lipogenesis in the adipose tissue was not affected by feeding frequency, lipogenesis was increased by an increase in the level of dietary energy inputs. Feeding frequency did not influence the body composition and energy concentration in the empty body of pigs fed 240 and 340 kcal ME/W0.75kg but frequent feeding increased percent water and reduced percent fat in pigs fed 140 kcal ME/W0.75kg daily. Several of the latter pigs were in negative energy balance.

EFFECTS OF CROSSBREEDING AND SEX ON ENERGY REQUIREMENTS AND UTILIZATION BY YOUNG PIGS

The influence of crossbreeding and sex on digestible (DE) and metabolizable (ME) energy values, fasting heat production (FHP), energy requirement for maintenance and growth, and on the efficiency of utilization of metabolizable energy in young weanling pigs, was investigated by employing a comparative slaughter technique. The pigs obtained by insemination of Yorkshire sows with pooled semen (equal number of sperms) from purebred Yorkshire and Hampshire boars, were identified for genotype by blood-group typing. A total of 37 pigs was used in this study, of which 9 pigs selected at random were killed to provide the initial body composition and energy status of pigs in the feeding experiment. The remaining 28 pigs (16 purebred: 8 male and 8 female; and 12 crossbred: 6 male and 6 female) were allotted at random to a feeding experiment of a randomized complete block design involving a 2 × 2 × 2 factorial arrangement (purebred vs. crossbred, male vs. female, and level of dietary energy input: 130 and 330 kcal ME/Wkg0.75 daily). One metabolism trial with each pig individually kept in a crate was conducted during the 4th week of the 40-day feeding period. The coefficients of DE and ME were 89.2 and 84.2%, respectively, and were not influenced by sex or genotype. An interaction was observed in the estimates of the fasting heat production and energy requirement for maintenance. Purebred Yorkshire males had a greater fasting heat production than Hampshire × Yorkshire males, whereas females of the two breeding groups had similar values. The apparent efficiency of utilization of ME was 76% and the net efficiency of utilization of ME available above maintenance was 66%. The energetic efficiency and the net energy value of the diet were similar for both breeding groups and sex. The mechanism of rapid gains due to crossbreeding was investigated.

Growth responses and root porosity of rice in relation to temperature, light intensity and aeration

Experiments were conducted under which rice plants were grown under three energy input levels (temperature and light) and two solution-oxygen concentrations. The rice variety was Colusa. Increasing the energy input increased total top growth. There was no significant effect of solution-oxygen concentration on top growth. The highest number of tillers developed under medium energy input followed by high energy input and the least under low energy input. There was a trend towards more tiller production under low oxygen conditions as compared to high oxygen. Decreasing the oxygen supply increased the dry weight production of roots under the two higher energy input levels, but had no significant effect under the low energy input. The highest amount of root growth occurred under high and medium energy input and least under lower energy input. Increasing the energy input increased the percent root porosity, but the oxygen level had no significant effect on root porosity. None of the treatments had a significant effect on nitrogen concentration in the tops. The amount of water necessary per unit dry matter production had a trend towards increase with increased energy input level and also significantly higher under low oxygen as compared to high oxygen conditions.

Interrelationships among Energy Input, Body Size, Age and Body Composition of Sheep

Interactions of age, body weight and energy intake on the proximate chemical composition and energy value of the body were examined in 26 Shropshire, male-castrate sheep. Body weight at a given age was manipulated by imposing on a given animal one of two levels of energy input (averaging 278 and 421 kcal of gross energy/1 kg empty-body weight 0.73 per day). The amounts of body components at a given age were greater in sheep receiving the high intake of energy than in those supplied the low level. The relationships between the body components and body weight, however, were not different for the two energy input levels. Thus, energy input, within the range studied, did not influence body composition in a manner independent of its effect on body mass. In animals containing less than 31% of fat, the amounts of body components increased linearly with increasing body weight; above this concentration of fat, the weights of water and protein increased at decreasing rates and the amounts of fat and energy increased at increasing rates, as body weight increased. The overall best fit of the relationships between the body components and body weight was provided by the model, Y = a Xb. For these relationships, the R2 values for the predictands other than ash ranged from 0.939 to 0.982. The use of age in addition to body weight as the predictors increased the R2 values by only 0.002 to 0.019 over those computed between body weight alone and the various predictands. Thus, body composition in sheep was not related to prior energy intake, only slightly associated with age, but was chiefly associated with body weight.

Effects of Light Intensity, Temperature, and Root Gaseous Environment on Growth of Nicotiana tabacum L.1

AbstractThe response of Nicotiana tabacum L. plants to various gaseous treatments (O2, CO2, N2) in the root environment was determined by microscopic examination of roots and measurements of stem diameter and leaf area. Superimposed on the gaseous treatments were three environmental energy input levels in which light intensity, air temperature, and nutrient solution temperature were varied. The plants were grown in an artificially lighted, controlled environment room with roots in an intermittent nutrient solution mist in airtight chambers. The roots were treated with gaseous mixtures for 24 hours and then returned to an atmosphere of air for a 5‐day recovery period. Mixtures of 1% O2 in N2, with or without CO2 present, reduced plant growth slightly at 1,000 ft‐c light intensity and 18.3C day temperature, but these mixtures progressively decreased growth as light and temperature increased. At 1,000 ft‐c light intensity and 18.3C day temperature a pure N2 treatment inhibited growth of plants; however, plants slowly resumed growth during recovery. At 4,000 ft‐c light intensity and 29.4C day temperature, N2 treatments killed the root system. Data obtained from measurements of stem diameters, leaf area, root weights, and water use suggest that the survival and growth of plants subjected to poor soil aeration is largely dependent on the ambient temperature and light intensity.

Comparison of the output spectra of krypton and xenon filled flashtubes

The spectral output of krypton filled flashtubes has been investigated and compared to that of xenon filled tubes. It was observed that although xenon has a higher luminous efficiency than krypton, the krypton output is 150 to 200 percent of the xenon output at 810 nanometers depending on the input energy level. The implication is that krypton is a more efficient pumping source for lasers with an absorption band in the region of 810 nanometers.

Generation of Transient Acoustic Impulses, Using a Novel Underwater Spark Sound Source

Investigations of an underwater, impulsive-sound-generating device are described. The device employs electric spark discharge between two volumes of sea water that are separated by a dielectric containing a small aperture. The spark occurs in and adjacent to the aperture, remote from the metal electrodes. Parametric relationships are shown for the pressure-time characteristics of the impulses radiated from single sparks as functions of circuit variables, aperture-electrode geometry variations, and static pressure. Results of input energy level variations up to 5000 J are reported, with corresponding peak-pressure outputs at 1 yd ranging up to 130 dB re 1 dyn/cm2 and pulse durations of 50 μsec. Parallel operation of more than one spark is also described, as are aperture deterioration and failure mechanisms encountered during the investigation. It is concluded that the operating characteristics of the device offers advantages within limits where precisely controlled, transient acoustic impulses of relatively low energy are desired.