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1
Weiss, William P., and Alexander W. Tebbe. "Estimating digestible energy values of feeds and diets and integrating those values into net energy systems." Translational Animal Science 3, no. 3 (November 5, 2018): 953–61. http://dx.doi.org/10.1093/tas/txy119.
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Abstract The California Net Energy System (CNES) used a combination of measured and tabular metabolizable energy (ME) values and changes in body composition gain to determine net energy requirements for maintenance and gain and their corresponding dietary concentrations. The accuracy of the CNES depends on the accuracy of the feed ME values. Feed or diet ME values can be measured directly but are expensive and require specialized facilities; therefore, most ME values are estimated from digestible energy (DE) values, which are often estimated from the concentration of total digestible nutrients (TDN). Both DE and TDN values are often from tables and not based on actual nutrient analysis. The use of tabular values eliminates important within-feed variation in composition and digestibility. Furthermore, the use of TDN to estimate DE does not account for important variation in the gross energy value of feeds. A better approach would be to estimate DE concentration directly from nutrient composition or in vitro (or in situ) digestibility measurements. This approach incorporates within-feed variation into the energy system and eliminates the issues of using TDN. A widely used summative equation based on the commonly measured feed fractions (ash, crude protein, neutral detergent fiber, and fat) has been shown to accurately estimate DE concentrations of many diets for cattle; however, deficiencies in that equation have been identified and include an overestimation of DE provided by fat and an exaggerated negative effect of intake on digestibility. Replacing the nonfiber carbohydrate term (which included everything that was not measured) in the equation with measured starch concentration and residual organic matter (i.e., nonfiber carbohydrate minus starch) should improve accuracy by accounting for more variation in starch digestibility. More accurate estimates of DE will improve the accuracy of ME values, which will ultimately lead to more accurate NE values.
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Santoso, Arif Dwi, Kardono ., and Joko P. Susanto. "PENGARUH EXTERNALITAS PADA NET ENERGY RATIO PRODUKSI BIODIESEL MIKROALGA = Externalities Effect on Net Energy Ratio of Microalgae Biodiesel Production." Jurnal Teknologi Lingkungan 14, no. 2 (December 1, 2016): 89. http://dx.doi.org/10.29122/jtl.v14i2.1426.
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In the future, Indonesia is predicted to be hit by national energy crisis so that it needs to do some efforts to overcome its dependences on these fossil energy sources. One of the efforts to lower high dependency on fossil energy sources is to find renewable energy sources. Microalgae has a great potential as a renewable energy source because it has the advantages of high productivity and sustainability. Development of microalgal biomasses as a renewable energy source is however, constrained by high cost of biomass production and low value of NER (net energy ratio) comparing tothese of other biomasses, like palm oil, jatrophaand tubers. Literature study shows that the method of NER calculation on biodiesel production does not yet include environmental variables. This researchis therefore to evaluate the values of NER before and after the addition of environmental commodity variables that consist of social, environmental and land use cost. Results of NER values calculatedusing existing LCA and modification LCA method are found to be 0,62 ± 0,078 and 0,60 ± 0,075 for algal biodiesel and 4,17 ± 0,79 and 3,22 ± 0,61 for palm biodiesel. The lower value of NER value differences for algal biomass indicates that biodiesel production from algal biomass is more environmentally-friendly. In addition, it is predicted that microalgae will have a significant contribution in the green house gases (GHGs) mitigation by replacing fossil fuel in the future through its role as a biodiesel. Keywords: net energy ratio, life cycle analysis, environmental commodity, microalgae, biodieselAbstrakDi masa depan, Indonesia diperkirakan akan dilanda krisis energi nasional sehingga perlu melakukan upaya untuk mengatasi ketergantungan terhadap energi fosil tersebut. Salah satu upayauntuk menurunkan ketergantungan pada energi fosil adalah untuk menemukan sumber energi terbarukan. Mikroalga memiliki potensi besar sebagai sumber energi terbarukan karena memiliki keuntungan dari produktivitas tinggi. Pengembangan biomasa mikroalga sebagai sumber energi terbarukan terkendala oleh tingginya biaya produksi dan nilai rendah APM (rasio energi bersih) dibandingkan dengan biomasa lainnya, seperti kelapa sawit ataupun umbi-umbian. Studi literatur menunjukkan bahwa metode perhitungan APM pada produksi biodiesel belum menyertakan variabel lingkungan. Oleh karena itu penelitian ini adalah untuk mengevaluasi nilai-nilai APM sebelum dansesudah penambahan variabel komoditas lingkungan yang terdiri dari biaya sosial, lingkungan dan penggunaan lahan. Hasil nilai NER dihitung dengan menggunakan LCA yang ada dan metode LCAmodifikasi yang ditemukan 0,62 ± 0078 dan 0,60 ± 0,075 untuk biodiesel alga dan 4,17 ± 0,79 dan 3,22 ± 0,61 untuk biodiesel sawit. Nilai yang lebih rendah dari perbedaan nilai APM untuk biomassaalga menunjukkan bahwa produksi biodiesel dari biomassa alga lebih ramah lingkungan. Selain itu, diperkirakan bahwa mikroalga akan memiliki kontribusi yang signifikan dalam mitigasi gas rumahkaca (GRK) dengan mengganti bahan bakar fosil. Kata kunci: rasio energi, analisa siklus hidup, komoditas lingkungan, mikroalga, biodiesel
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Owens, Fredric N., and Robert B. Hicks. "Can net energy values be determined from animal performance measurements? A review of factors affecting application of the California Net Energy System1." Translational Animal Science 3, no. 3 (June 1, 2019): 929–44. http://dx.doi.org/10.1093/tas/txy130.
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Abstract The California Net Energy System (CNES) can reliably project performance of feedlot cattle based on three factors: expected dry matter intake (DMI), some index of degree of maturity of cattle linked to body composition (fat and protein content), and an estimate of the net energy (NE) content of the diet. The CNES allowed feedlot managers to monitor growth and efficiency of individual pens of cattle. Through assigning distinct values for net energy for maintenance (NEm) vs. net energy for gain (NEg) of the metabolizable energy (ME) present in feeds, the CNES enables valid economic comparisons among feedstuffs, an appraisal not feasible based on total digestible nutrients or digestible energy (DE) values. Because NEm and NEg are linked mathematically to ME, the CNES also allows performance-adjusted ME (paME) value of diets to be calculated from observed DMI and growth or carcass measurements. Compared with other productivity measures (e.g., average daily gain and gain-to-feed ratio) that are confounded with and affected by DMI, the CNES logically separates production responses by cattle into two factors—DMI and ME of the diet. This enables research scientists or cattle producers to appraise responses within these two factors independently. In feeding studies, means of paME values were related closely to ME values of diets calculated from the ME of diet ingredients. But unlike ME values projected from diet analyses, paME estimates are affected by environmental conditions (e.g., season, weather, animal interactions, stress, nutritional history and deficiencies, associative effects of feeds, imprecise feed management, and animal healthfulness and disorders). These factors typically overestimate ME intake or increase energy requirements, both of which decrease energetic efficiency. By comparing paME with ME values calculated from diet composition, logical reasons behind performance responses to and quantitative benefits from feed additives, grain processing, hormone implants, and animal management can be appraised. Considering the evolution in cattle types, management and marketing conditions, and changes in diet ingredients and processing that have occurred during the past 50 yr, updating by a skilled committee to correct certain anomalies within the CNES as currently being applied seems appropriate. Developing simplified spreadsheets could help users evaluate their own dietary and management conditions and assure that the CNES continues to be widely applied by the feedlot industry within the United States and worldwide.
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O'Mara, F. P. "Relative net energy values of grass silage and maize silage for dairy cows." Proceedings of the British Society of Animal Science 1995 (March 1995): 5. http://dx.doi.org/10.1017/s0308229600027768.
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The acreage of maize grown for silage in Ireland has increased in the last few years. This study is concerned with determining it's feeding value relative to grass silage. If energy content is used as the indicator of feeding value, net energy values must be used to allow valid comparisons between feedstuffs. Therefore relative net energy values were calculated for grass and maize silage. However maize silage has very good intake characteristics and this needs to be taken into account in assessing it's value. Relative intake values were calculated for the grass and maize silage's and these were combined with the net energy values to give an overall feeding value.
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Chizzotti, Mario Luiz, Sebastião de Campos Valadares Filho, Pedro Del Bianco Benedeti, and Flávia Adriane de Sales Silva. "California net energy system for Bos taurus indicus." Translational Animal Science 3, no. 3 (June 1, 2019): 991–98. http://dx.doi.org/10.1093/tas/txz016.
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Abstract The California net energy system (CNES) was the reference for the development of most energy requirement systems worldwide, such as Nutrient Requirements of Beef Cattle (NASEM, Nutrient requirements of beef cattle, 8th Revised ed, 2016) and Brazilian Nutrient Requirements of Zebu and Crossbred Cattle (Valadares Filho, S. C., L. F. C. Silva, M. P. Gionbelli, P. P. Rotta, M. I. Marcondes, M. L. Chizzotti, and L. F. Prados, BR-CORTE: nutrient requirements of zebu and crossbred cattle, 3rd ed, 2016). This review aimed to compare methods used by NASEM and BR-CORTE to estimate the energy requirements for beef cattle. The net energy requirements for maintenance (NEm) of BR-CORTE is based on empty body weight (EBW), whereas NASEM uses shrunk body weight (SBW), but the Bos taurus indicus presents 10% to 8% lower NEm than Bos taurus taurus. We have compared animals with different EBW and SBW but with same equivalent empty body weight/standard reference weight ratio (0.75), as both systems have suggested different mature weights. Both systems predicted similar net energy requirements for gain (NEg) for animals with 1.8 kg of daily gain. However, estimated empty body gain was lower for NASEM estimations when the same metabolizable energy for gain is available. For pregnancy and lactation of beef cows, the NEm and net energy requirements for pregnancy (NEp) of a Zebu cow estimated by BR-CORTE were lower than the values estimated by NASEM. Furthermore, the magnitude of differences between these systems regarding NEp increased as pregnancy days increase. The NASEM and BR-CORTE systems have presented similar values for energy requirement for lactation (0.72 and 0.75 Mcal/kg milk, respectively).
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MacDougall, Iain, Ollie Glade-Wright, Bindi Gove, and Todd Berkinshaw. "Net zero 2020." APPEA Journal 61, no. 1 (2021): 42. http://dx.doi.org/10.1071/aj20070.
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Cooper Energy recognises the challenge of climate change, the goals of the Paris Agreement and the role of both energy companies and society in reducing greenhouse gas emissions, given the proportion of emissions generated from energy production and consumption. In 2020, Cooper Energy became Australia’s first carbon neutral domestic gas company. We fully offset our fiscal year 2020 Scope 1 (direct), Scope 2 (indirect) and controllable Scope 3 (business travel and embedded energy) greenhouse gas emissions. The company was recognised for this achievement with the award of the 2020 South Australian Premier’s Award for Environment. We plan to offset our carbon emissions annually, recognising the long-term benefits to our business, the environment and the communities where we operate. To achieve net zero carbon emissions in 2020, Cooper Energy partnered with Greening Australia’s Biodiverse Carbon and invested in the Morella Biodiversity project, at the eastern end of the Coorong in south-east South Australia. The partnership also covers the early conceptual stages to progress a similar project in Victoria near to our Gippsland and Otway operations. This paper expands on the strategy, challenges, risks, opportunities and co-benefits of taking a forward-looking position in this area, which is aligned with The Cooper Energy Values and the direction of the broader community. This includes the decision to favour investment in appropriate high quality domestic projects near to our operational activities over lower cost international projects or simply purchasing offset credits on a carbon market. The paper explores how our net zero commitment will act as a driver to reduce emissions intensity in our operations and add value for Cooper Energy stakeholders.
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Sarmiento-Franco, L., M. G. MacLeod, and J. M. McNab. "True metabolisable energy, heat increment and net energy values of two high fibre foodstuffs in cockerels." British Poultry Science 41, no. 5 (December 2000): 625–29. http://dx.doi.org/10.1080/713654992.
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Noblet, J., H. Fortune, C. Dupire, and S. Dubois. "Digestible, metabolizable and net energy values of 13 feedstuffs for growing pigs: effect of energy system." Animal Feed Science and Technology 42, no. 1-2 (June 1993): 131–49. http://dx.doi.org/10.1016/0377-8401(93)90029-j.
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Noblet, J., X. S. Shi, and S. Dubois. "Metabolic utilization of dietary energy and nutrients for maintenance energy requirements in sows: basis for a net energy system." British Journal of Nutrition 70, no. 2 (September 1993): 407–19. http://dx.doi.org/10.1079/bjn19930135.
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Digestible energy (DE), metabolizable energy (ME) and net energy for maintenance (NEm) values of a set of fourteen diets were measured in six adult sows fed at and below their maintenance energy level. The efficiency of ME for NEm was estimated from heat production (HP) measurements (indirect calorimetry) at these different feeding levels. HP was partitioned between HP due to physical activity, thermic effect of food (TEF) and fasting heat production (FHP). The amounts of DE digested in the small intestine or in the hindgut were measured. Equations for prediction of NEm from dietary characteristics were calculated. HP at maintenance level averaged 400 kJ/kg body-weight0.75, 16 and 19% of the total being due to physical activity and TEF respectively. The efficiency of ME for NEm averaged 77·4% with higher values for digestible diethyl ether extract (100%) and starch + sugar (82 %). The efficiencies of digestible crude protein (N × 6·25) and digestible residue averaged 69 and 56 % respectively. The energy absorbed from the small intestine was used more efficiently than the energy fermented in the hindgut (82 v. 59%). These values are comparable with those obtained in growing pigs. The NEm content of diets can be predicted accurately from equations including DE (or ME) values and some dietary chemical characteristics.
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Old, Carl A., Ian J. Lean, and Heidi A. Rossow. "Mathematical absurdities in the California net energy system." Translational Animal Science 3, no. 3 (June 1, 2019): 1018–28. http://dx.doi.org/10.1093/tas/txz020.
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Abstract Net energy systems, such as the California Net Energy System (CNES), are useful for prediction of input:output relationships not because of fidelity to the laws of thermodynamics, but because they were designed to predict well. Unless model descriptions of input:output relationships are consistent with the laws of thermodynamics, conclusions regarding those relationships may be incorrect. Heat energy (HE) + recovered energy (RE) = ME intake (MEI) is basic to descriptions of energy utilization found in the CNES and is consistent with the laws of thermodynamics; it may be the only relationship described in the CNES consistent with the first law of thermodynamics. In the CNES, efficiencies of ME utilization for maintenance (km) and gain (kg) were estimated using ordinary least squares (OLS) equations. Efficiencies thus estimated using static linear models are often inconsistent with the biochemistry of processes underlying maintenance and gain. Reactions in support of oxidative mitochondrial metabolism are thermodynamically favorable and irreversible; these reactions yield ATP, or other high-energy phosphate bonds, used for what is generally termed maintenance. Synthesis of biomass (gain) is less thermodynamically favorable; reactions do not proceed unless coupled with hydrolysis of high-energy phosphate bonds and lie closer to equilibrium than those in support of oxidative mitochondrial metabolism. The opposite is described in the CNES (km > kg) due to failure of partitioning of HE; insufficient HE is accounted for in maintenance. Efficiencies of ME utilization (km and kg) as described in the CNES are variable. Further neither km nor kg are uniformly monotonic f (ME, Mcal/kg); for ME (Mcal/kg) <0.512 or >4.26, km are inconsistent with thermodynamically allowed values for efficiencies (>1.0); kg are a monotonically positive f (ME) concentration (Mcal/kg) for ME <3.27 Mcal/kg. For ME <1.42 Mcal/kg, kg are not in the range of thermodynamically allowed values for efficiencies (0 to 1.0). Variable efficiencies of ME utilization require that the first law may not be observed in all cases. The CNES is an excellent empirical tool for prediction of input:output relationship, but many CNES parameter estimates evaluated in this study lack consistency with biology and the laws of thermodynamics.
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Zamani, Pouya. "Statistical properties of proportional residual energy intake as a new measure of energetic efficiency." Journal of Dairy Research 84, no. 3 (August 2017): 248–53. http://dx.doi.org/10.1017/s0022029917000395.
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Traditional ratio measures of efficiency, including feed conversion ratio (FCR), gross milk efficiency (GME), gross energy efficiency (GEE) and net energy efficiency (NEE) may have some statistical problems including high correlations with milk yield. Residual energy intake (REI) or residual feed intake (RFI) is another criterion, proposed to overcome the problems attributed to the traditional ratio criteria, but it does not account for production or intake levels. For example, the same REI value could be considerable for low producing and negligible for high producing cows. The aim of this study was to propose a new measure of efficiency to overcome the problems attributed to the previous criteria. A total of 1478 monthly records of 268 lactating Holstein cows were used for this study. In addition to FCR, GME, GEE, NEE and REI, a new criterion called proportional residual energy intake (PREI) was calculated as REI to net energy intake ratio and defined as proportion of net energy intake lost as REI. The PREI had an average of −0·02 and range of −0·36 to 0·27, meaning that the least efficient cow lost 0·27 of her net energy intake as REI, while the most efficient animal saved 0·36 of her net energy intake as less REI. Traditional ratio criteria (FCR, GME, GEE and NEE) had high correlations with milk and fat corrected milk yields (absolute values from 0·469 to 0·816), while the REI and PREI had low correlations (0·000 to 0·069) with milk production. The results showed that the traditional ratio criteria (FCR, GME, GEE and NEE) are highly influenced by production traits, while the REI and PREI are independent of production level. Moreover, the PREI adjusts the REI magnitude for intake level. It seems that the PREI could be considered as a worthwhile measure of efficiency for future studies.
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Ouellet, D. R., J. R. Seoane, H. Lapierre, P. Flipot, and J. F. Bernier. "Net energy value of timothy and bromegrass silages for beef cattle." Canadian Journal of Animal Science 78, no. 1 (March 1, 1998): 107–14. http://dx.doi.org/10.4141/a97-023.
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Metabolizable energy (ME), net energy for maintenance and net energy for growth of grass silages were evaluated by the comparative slaughter technique using a 2 × 2 × 3 factorial design. Sixty medium frame beef steers (259 ± 29 kg BW) were divided in groups of five and fed during 3 months either Timothy (T) or Bromegrass (B) harvested at stem elongation (S) of the first cut or at boot stage of the aftermath (A). Forages were fed at one of three levels of intake: ad libitum (FF), 80% of FF, or 65% of FF. Silages averaged 26.9% DM, 16.0% CP and 37.7% ADF. Regression of logarithm of heat production (HE) against ME intake were similar for all silages (log HE = 0.00046*ME + 2.4923; r2 = 0.89). From this equation, fasting HE of 311 kJ kg−0.75 d−1, ME for maintenance of 559 kJ kg−0.75 d−1 and efficiency of utilization of energy for maintenance of 56% were determined. Regression of ME intake against retained energy (RE) were similar for all silages. Efficiency of ME utilization for growth was 33% using the regression of ME over RE with a ME requirement for maintenance fixed at 559 kJ kg−0.75 d−1. Net energy for maintenance and growth were similar for all silages, averaging 6.17 and 3.70 MJ kg−1, respectively. The use of a prediction equation based on ADF of forages underestimated ME values of silages by approximately 25%. Moreover, NRC (1984) equations that estimate NE from experimentally estimated ME values tended to overestimate the net energy of our grass silages. Key words: Net energy, grass silages, timothy, bromegrass, beef cattle
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Lalman, David L., Claire E. Andresen, Amanda L. Holder, Ryan R. Reuter, and Andrew P. Foote. "Application of the California Net Energy System to grazed forage: feed values and requirements." Translational Animal Science 3, no. 3 (June 1, 2019): 962–68. http://dx.doi.org/10.1093/tas/txz034.
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Abstract The California Net Energy System (CNES) has been successfully used for many years to generate estimates of grazing animal energy requirements, supplemental needs, and energy value of grazed forage diets. Compared to pen feeding situations, validation of feed nutritive value estimates or animal performance projections are extremely difficult in grazing animals because many of the system inputs are constantly changing. A major difficulty in applying this or any energy accounting system in the field is acquiring accurate estimates of forage intake. We discuss the various equations available to estimate forage intake for grazing animals with emphasis on beef cows. Progress has been made in recent years although there remains substantial discrepancy among various equations, particularly in the upper range of forage digestibility. Validation work and further development is needed in this area. For lactating cows, our conclusion is that the adjustment of intake for milk production (0.2 kg increase in forage intake per kg of milk produced) needs to be increased to a minimum of 0.35. A particular challenge with the CNES for grazing beef cows is the dramatic interaction that can occur between genetic potential for production traits and nutrient availability. Examples from literature are provided and a case study is presented demonstrating that energy requirements are dynamic and depend on nutrients available in grazing systems. The CNES is a useful tool in grazing beef cattle management although there remains substantial opportunity and need to improve inputs and validate the system in grazing situations.
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Péter Kovács, János Lazányi, and Géza Nagy. "Changes of chemical composition and nutritive values of Reed Canary Grass (Phalaroides arundinacea) in first growth." Acta Agraria Debreceniensis, no. 40 (December 1, 2010): 37–42. http://dx.doi.org/10.34101/actaagrar/40/2702.
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Change in chemical composition and nutritive value of Reed Canary Grass (Phalaroides arundinacea) were investigated in springtime in 2004-2006. The nutritive value of Reed Canary Grass was observed between the end of April and the middle of June relating to the following parameters: crude protein, crude fibre, crude fat, ash, N-free extract, net-energy growth, net-energy maintenance, Metabolizable Protein Energy dependent,Metabolizable Protein N-dependent.It was also analysed whether a relationship between the climatic factors affecting the growing period as well the chemical composition of grasses and the annual weather were looked for. For the estimation of weather conditions the climate index was calculated. A correlation can be detected between the change of parameters of nutritive value and the quality of the current year. Between 2004 and 2006, the result of the analysis of nutritive value indicated a significant difference with respect to each chemical composition at the rate of P<0.01 depending on the time when the samples were taken. According to the outlined data it can be stated that the change of the value of crude protein and ash show decreasing endency agreeing the research literature. In parallel with the change of nutritive value, the amount of crude fibre and N-free extract increased. However, the value of Net-Energy maintenance revealed an alteration only in the first half of the observed period. The same alteration tendency can be detectedin the Net-Energy growth.
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Liu, W., X. G. Yan, H. M. Yang, X. Zhang, B. Wu, P. L. Yang, and Z. B. Ban. "Metabolizable and net energy values of corn stored for 3 years for laying hens." Poultry Science 99, no. 8 (August 2020): 3914–20. http://dx.doi.org/10.1016/j.psj.2020.03.041.
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Bowman, Jan G. P., Darrin L. Boss, Lisa M. M. Surber, and Tom K. Blake. "Estimation of the net energy value of barley for finishing beef steers1." Translational Animal Science 3, no. 4 (July 1, 2019): 1550–60. http://dx.doi.org/10.1093/tas/txz128.
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Abstract The objective of this study was to identify barley grain characteristics measured by laboratory procedures that could be used to predict barley energy content for finishing beef steers. Twenty-eight different barley genotypes were evaluated including 18 cultivars and 10 experimental lines. Laboratory analysis of barley samples included bulk density, particle size, N, ADF, starch, and ISDMD (in situ DM disappearance after 3 h of ruminal incubation). Animal performance data (BW, DMI, ADG, steer NEm, and NEg requirements) were collected from 26 feedlot experiments conducted in Montana and Idaho during a 10-yr period and were used to estimate barley NEm and NEg content. A total of 80 experimental units were available with each experimental unit being a diet mean from an individual feedlot experiment. Fifty-eight of the 80 experimental units were randomly selected and used in the development data set and the remaining 22 experimental units were used in the validation data set. Forward, backward, and stepwise selection methods were used to identify variables to be included in regression equations for NEm using PROC REG of SAS. Barley samples in the model development data set represented a wide range in concentrations (DM basis): N (1.6% to 2.8%), ISDMD (25.7% to 58.7%), ADF (3.6% to 8.0%), starch (44.1% to 62.4%), particle size (1,100 to 2,814 µm), and bulk density (50.8 to 69.4 kg/hL). The barley grain characteristics of particle size, ISDMD, starch, and ADF were the most important variables in six successful models (R2 = 0.48 to 0.60; P = 0.001). The six prediction equations gave mean predicted values for NEm ranging from 1.99 to 2.05 Mcal/kg (average 2.04 Mcal/kg; 0.45% CV). The mean actual NEm values from animal performance trials ranged from 1.75 to 2.48 Mcal/kg (average 2.03 Mcal/kg; 6.5% CV). The mean bias or difference in predicted vs. actual values ranged from −0.001 to 0.005 Mcal/kg. Barley NEg values calculated from animal performance ranged from 1.13 to 1.78 Mcal/kg (average 1.39 Mcal/kg; 8.4% CV). Average predicted barley NEm and NEg were 0.02 and 0.01 Mcal/kg less, respectively, than the 2.06 Mcal/kg NEm and 1.40 Mcal/kg NEg reported by NRC. Barley NE can be predicted from simple laboratory procedures which will aid plant breeders developing new feed varieties and nutritionists formulating finishing rations for beef cattle.
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Galyean, M. L., N. A. Cole, L. O. Tedeschi, and M. E. Branine. "BOARD-INVITED REVIEW: Efficiency of converting digestible energy to metabolizable energy and reevaluation of the California Net Energy System maintenance requirements and equations for predicting dietary net energy values for beef cattle1." Journal of Animal Science 94, no. 4 (April 1, 2016): 1329–41. http://dx.doi.org/10.2527/jas.2015-0223.
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Markovic, J., R. Strbanovic, D. Terzic, R. Stanisavljevic, D. Djokic, T. Vasic, and B. Andjelkovic. "Estimation of red clover (Trifolium pratense L.) forage quality parameters depending on the stage of growth." Biotehnologija u stocarstvu 27, no. 4 (2011): 1563–69. http://dx.doi.org/10.2298/bah1104563m.
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The objective of this study was to investigate the changes that take place in nutrient values of red clover (Trifolium pratense L.) cv K-27 at different stages of growth in the second and the third cut. The samples from different stages of growth: mid-bud stage, around 60% flowering and full flowering were investigated for crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), digestible dry matter (DDM), dry matter intake (DMI), relative feed value (RFV), total digestible nutrients (TDN), net energy-lactation (NEl), net energy-maintenance (NEm) and net energy-gain (NEg) content. Higher content of crude protein was found in the third cut (262.1 g kg-1 of DM) than in the second cut (260.8 g kg-1 of DM) in the first stage of development. TDN, DDM, DMI, RFV, NEl, NEm and NEg were calculated according to the appropriate equations adapted from common formulas for forages. The stage of plant development has a significant influence on the chemical composition and the relative feed value of red clover. The achieved results show that adequate maturity stage for cutting might be at mid-bloom stage, when crude protein content, NEl, NEm and NEg content are high.
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Baťa, Robert, and Jan Fuka. "Modelling of Biofuel Potential as a Tool for Public Managers." Sustainability 10, no. 12 (November 23, 2018): 4380. http://dx.doi.org/10.3390/su10124380.
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Developing the efforts to implement sustainability policies in the energy field requires the most accurate information on the potential of available resources to properly implement concrete policies. Total net energy yields are interpreted in isolation, and studies providing information on yields of specific energy crops in net values are relatively rare. This article, therefore, provides a tool based on methodology combining Lifecycle Assessment (LCA) approaches and a model implemented in a stochastic Petri net environment to support managerial decision-making at a national and regional level. This tool allows for the comparison of net yields of more energy crops used in Central Europe. Additional crops can be added to the model. For the purpose of comparison, it is also possible to customize the model parameters for particular crops and the way they are cultivated. In comparison with oilseed rape, sugar beet, and wheat, the model shows best results in terms of net energy yields for sugar beet.
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Wendler, Gerd, Ute Adolphs, Adrian Hauser, and Blake Moore. "On the surface energy budget of sea ice." Journal of Glaciology 43, no. 143 (1997): 122–30. http://dx.doi.org/10.3189/s0022143000002884.
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AbstractThe surface energy budget was investigated during a cruise through the pack ice in the Southern Ocean. The time of observation was close to mid-summer. Some of the more important findings were: The mean albedo varied from 11 % for open water to 59% for 10/10 ice cover. Hourly values span the range from 6% (open water) to 76% (total ice cover).The net heat flux into the ocean (B) was on average 109 W m−2, If this energy were used solely for melting of sea ice, 30 mm could be melted each day.For low surface albedos (ice concentration below 7/10), the net radiation increased with decreasing cloudiness. However, the opposite was the case for a high surface albedo. The last point shows the importance of clouds on the surface energy budget. Not only should their presence or absence be known but also the reflectivity of the underlying surface, as it might change the net radiation in opposite ways.
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Wendler, Gerd, Ute Adolphs, Adrian Hauser, and Blake Moore. "On the surface energy budget of sea ice." Journal of Glaciology 43, no. 143 (1997): 122–30. http://dx.doi.org/10.1017/s0022143000002884.
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AbstractThe surface energy budget was investigated during a cruise through the pack ice in the Southern Ocean. The time of observation was close to mid-summer. Some of the more important findings were:The mean albedo varied from 11 % for open water to 59% for 10/10 ice cover. Hourly values span the range from 6% (open water) to 76% (total ice cover).The net heat flux into the ocean (B) was on average 109 W m−2, If this energy were used solely for melting of sea ice, 30 mm could be melted each day.For low surface albedos (ice concentration below 7/10), the net radiation increased with decreasing cloudiness. However, the opposite was the case for a high surface albedo.The last point shows the importance of clouds on the surface energy budget. Not only should their presence or absence be known but also the reflectivity of the underlying surface, as it might change the net radiation in opposite ways.
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Liu, W., G. H. Liu, R. B. Liao, Y. L. Chang, X. Y. Huang, Y. B. Wu, H. M. Yang, H. J. Yan, and H. Y. Cai. "Apparent metabolizable and net energy values of corn and soybean meal for broiler breeding cocks." Poultry Science 96, no. 1 (January 2017): 135–43. http://dx.doi.org/10.3382/ps/pew195.
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Silva, Catarina, and Maria João Rosa. "Energy performance indicators of wastewater treatment: a field study with 17 Portuguese plants." Water Science and Technology 72, no. 4 (May 20, 2015): 510–19. http://dx.doi.org/10.2166/wst.2015.189.
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The energy costs usually represent the second largest part of the running costs of a wastewater treatment plant (WWTP). It is therefore crucial to increase the energy efficiency of these infrastructures and to implement energy management systems, where quantitative performance metrics, such as performance indicators (PIs), play a key role. This paper presents energy PIs which cover the unit energy consumption, production, net use from external sources and costs, and the results used to validate them and derive their reference values. The results of a field study with 17 Portuguese WWTPs (5-year period) were consistent with the results obtained through an international literature survey on the two key parcels of the energy balance – consumption and production. The unit energy consumption showed an overall inverse relation with the volume treated, and the reference values reflect this relation for trickling filters and for activated sludge systems (conventional, with coagulation/filtration (C/F) and with nitrification and C/F). The reference values of electrical energy production were derived from the methane generation potential (converted to electrical energy) and literature data, whereas those of energy net use were obtained by the difference between the energy consumption and production.
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Zhong, W., L. L. Mu, F. F. Han, G. L. Luo, X. Y. Zhang, K. Y. Liu, X. L. Guo, H. M. Yang, and G. Y. Li. "Estimation of the net energy and protein requirements for maintenance of male arctic foxes (Alopex lagopus) during the growth period12." Journal of Animal Science 97, no. 11 (October 26, 2019): 4579–87. http://dx.doi.org/10.1093/jas/skz253.
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Abstract The maintenance requirements of net energy and net protein were assumed to represent the most accurate and important values totally for the animal’s utilization. The objective of this experiment was to determine the net energy and net protein requirements for maintenance of growing arctic foxes. The experiments was evaluated using regression models estimated from data collected by means of indirect calorimetry, nitrogen balance trials, and digestion and metabolism experiments. Thirty-six growing arctic foxes (3 487 ± 261.7 g) at the age of 85 days were randomly assigned to four groups with 9 animals in each group. Arctic foxes were fed a complete formula diet at four intake levels (100%, or 80%, 60%, and 40% of feed requirements) from 24 July 2017 to 23 September 2017. Arctic foxes in each treatment were kept individually in respiration chambers after 1-d adaptation at day 2 for a 3-d balance trial and then at day 5 followed by a 3-d fasting period. The metabolizable energy intake (MEI), heat production in the fed state (HP), and retained energy (RE) of arctic foxes significantly decreased (P < 0.01) as the feed intake level decreased. Fasting heat production (FHP) of arctic foxes was not influenced by feed intake level (P > 0.05). The metabolizable energy maintenance requirement (MEm) and net energy maintenance requirement (NEm) estimated from the linear relationship between RE and MEI were 230 and 217 kJ/kg of body weight BW0.75/d, respectively. The MEm and NEm estimated by logarithmic regression of HP on MEI were 225 and 209 kJ/kg BW0.75/d, respectively. The net N maintenance requirement (NNm) and net protein maintenance requirement (NPm) estimated from the linear relationship between retained nitrogen (RN) and daily nitrogen intake (NI) were 179.6 mg/kg BW0.75/d and 1.123 g/kg BW0.75/d, respectively. It is concluded that NEm and NPm values obtained fill the net energy and protein requirements shortage, and provide the basic data for establishing the standard of nutrition demand of breeding arctic foxes in China.
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Yang, Ting, Lexiao Yu, Min Wen, Hua Zhao, Xiaoling Chen, Guangmang Liu, Gang Tian, Jingyi Cai, and Gang Jia. "Modeling net energy requirements of 2 to 3-week-old Cherry Valley ducks." Asian-Australasian Journal of Animal Sciences 33, no. 10 (October 1, 2020): 1624–32. http://dx.doi.org/10.5713/ajas.19.0561.
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Objective: A total of three hundred unsexed ducks were utilized to estimate net energy requirements of maintenance (NEm) and weight gain (NEg) for 2 to 3-week-old Cherry Valley ducks and to establish a model equation to predict NE requirements using the factorial method.Methods: To determine the apparent metabolizable energy (AME) of the diet, fifty 7-day-old ducks at approximately equal body weights (BWs) were randomly assigned into five groups that were fed at different levels (ad libitum, 85%, 75%, 65%, and 55% of ad libitum intake), and the endogenous acid-insoluble ash as indigestible marker. The two hundred and fifty 7-day-old ducks were used for a comparative slaughter experiment. At the beginning of the experiment, ten ducks were sacrificed to determine the initial body composition and energy content. The remaining ducks were randomly assigned into five groups (same as metabolic experiment). Ducks of the ad libitum group were slaughtered at 14 and 21-dayold. At the end of the experiment, two ducks were selected from each replicate and slaughtered to determine the body composition and energy content.Results: The results of the metabolizable experiment showed AME values of 13.43 to 13.77 MJ/kg for ducks at different feed intakes. The results of the comparative slaughter experiment showed the NEm value for 2 to 3-week-old Cherry Valley ducks was 549.54 kJ/kg of BW0.75/d, and the NEg value was 10.41 kJ/g. The deposition efficiency values of fat (Kf) and crude protein (Kp) were 0.96 and 0.60, respectively, and the values of efficiency of energy utilization (Kg) and maintenance efficiency (Km) were 0.75 and 0.88, respectively.Conclusion: The equation for the prediction of NE requirements for 2 to 3-week-old Cherry Valley ducks was the following: NE = 549.54 BW0.75+10.41 ΔW, where ΔW is the weight gain (g).
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Lolli, Nicola, Anne Gunnarshaug Lien, and Øystein Rønneseth. "Cost Optimization of a Zero-Emission Office Building." Buildings 10, no. 12 (November 30, 2020): 222. http://dx.doi.org/10.3390/buildings10120222.
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The cost-effectiveness of energy efficiency measures meant to achieve a zero-emission office building is investigated and compared to business as usual energy efficiency measures. The laboratory for zero emission buildings, the ZEB Lab, located in Trondheim, Norway, is an office building designed and built to compensate its lifecycle emissions with the use of a large array of building-integrated photovoltaic panels, pursuing a zero-emissions ambition level. Three design alternatives are investigated by downgrading the building insulation level to the values recommended by the currently enforced Norwegian building code, the byggteknisk forskrift TEK17. A sensitivity analysis of the variation of the installed area of the photovoltaic panels is performed to evaluate if smaller areas give better cost performances. Net present values are calculated by using three scenarios of future increase of electricity price for a time horizon of 20 years. Results show that business as usual solutions give higher net present values. Optimized areas of the photovoltaic panels further increase the net present values of the business as usual solutions in the highest electricity price scenario. The zero-emission ambition level shows a higher net present value than that of the business as usual solutions for a time horizon of at least 36 years.
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EARLY, R. J., O. MAHGOUB, and C. D. LU. "Energy and protein utilization for maintenance and growth in Omani ram lambs in hot climates. I. Estimates of energy requirements and efficiency." Journal of Agricultural Science 136, no. 4 (June 2001): 451–59. http://dx.doi.org/10.1017/s0021859601008899.
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Energy requirements for maintenance and growth were estimated by comparative slaughter in Omani male lambs during the hot summer months (July–October: maximum temperature, 48 °C). Weaned lambs (n = 10 per diet) were fed one of three totally mixed, 160 g CP/kg DM diets that contained 600, 400 or 200 g rhodesgrass hay/kg for low (9·98 MJ/kg, medium (10·3 MJ/kg) and high (11·4 MJ/kg) energy contents, respectively. All diets were balanced to meet the minimum nutritional needs for maximum growth. The trial lasted for 113–114 days. The purpose of having three diets was to induce a broad spectrum of growth rates that could be used in regression analysis (tested for linear, quadratic and exponential effects). Metabolizable energy (ME) intake was regressed on live weight (LW), empty body weight, tissue energy and tissue protein gain and vice versa. Coefficients of determinations were not significantly improved by quadratic or logarithmic regressions over linear relationships. Geometric mean regressions were used to control further biases due to major axis dependence when Y is regressed on X or vice versa. Based on tissue energy gain, the best estimates of ME required for maintenance (MEm) and gain (MEg) were 526 kJ/kg LW0·75/d and 42·1 kJ/kg LW0·75/g LW gain, respectively. Net energy values for maintenance (NEm) and gain (NEg) were 278 kJ/kg LW0·75/d and 20·6 kJ/kg LW0·75/g LW gain, respectively. These equations predicted MEm and NEm requirements that were similar to or slightly greater than those established by the US National Research Council (1985) and the UK Agricultural and Food Research Council (1993) for growing male lambs. The MEg and NEg requirements were substantially greater (by 43–89%) in this respect. Efficiency values were calculated as net energy available for maintenance or gain divided by the metabolizable energy available for maintenance or gain. The efficiency of metabolizable energy used for maintenance and gain was 0·50 and 0·52, respectively, and did not appear to be much different from values for other breeds of sheep in temperate climates. Dietary energy concentrations did not affect the efficiency of energy deposition. The data suggest that Omani sheep in hot climates have greater NEg requirements, and consequently MEg requirements, than other breeds of sheep in temperate climates.
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Drobná, J., and J. Jančovič. "Estimation of red clover (Trifolium pratense L.) forage quality parameters dependingon the variety, cut and growing year." Plant, Soil and Environment 52, No. 10 (November 17, 2011): 468–75. http://dx.doi.org/10.17221/3468-pse.
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A field trial was conducted to determine the nutritive value of eight Slovak and Czech red clover varieties and to quantify the effects of variety, cut and year on red clover forage quality. The differences between forage quality of the evaluated red clover varieties were significant for protein supplied when energy is limited in the rumen (PDIE), intestinal digestibility of rumen non-degraded protein (dsi), net energy values and ash content (P < 0.01). The achieved results show that the surpassing forage quality was given by diploid Viglana variety with high protein and energy values. The forage of tetraploid varieties Javorina and Dolina was outstanding in protein content, but had the lowest energy values. The nutritive value was significantly affected by cut. The first cut provided forage with a significantly lower (P < 0.01) crude protein (CP) content, CP digestibility, degradability of CP (degNL), protein supplied when nitrogen is limited in rumen (PDIN), PDIE and with a significantly higher crude fibre content and energy values (P < 0.01). The differences between varieties were more pronounced in the second and in the third cut. Significantly higher (P < 0.01) PDIE, PDIN, degNL, net energy values and ash contents were found in the first production year.
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Aldenhoven, Noud, Nestor A. Gutierrez, Neil W. Jaworski, and Harmen van Laar. "167 Analysis of variation in net energy prediction of feed ingredients fed to swine." Journal of Animal Science 98, Supplement_3 (November 2, 2020): 62. http://dx.doi.org/10.1093/jas/skaa054.111.
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Abstract Precision of NRC and CVB net energy (NE) prediction equations was investigated by taking into account natural and analyzed variation of the chemical components (e.g., moisture, protein, starch, NDF, ADF, sugars, fat) for six feed ingredients used in swine diets. Precision is defined as the variation of the NE formula given the variation of its chemical components. Stochastic variables were substituted for the component values and the variation in nutrient composition was algebraically, not statistically, propagated to the NE value for both equations. This was done both, for the naturally occurring variation as published in CVB, and for a range of analytical variation values associated with wet chemistry analysis based on a range of values obtained by published ring-tests. Consequently, variation of the NE value and the contribution to variation of each chemical component in the NE equation were calculated. The variation of NE prediction using CVB is lower than using NRC. The main contributor for increased variation of the NRC NE is the NDF fraction. Whereas in CVB, this is replaced by the NSP fraction which is computed as a residue from the other chemical component values, forcing the sum of the composition to add to 100%. Furthermore, it was determined that analyzing all nutrients, in particular NDF and ADF, did not always reduce the variation of the NE equations. In conclusion, analytical variation, especially fiber analysis, must be critically examined and, preferably, sum to 100% to increase precision in the prediction of NE in feed ingredients. Otherwise, the use of a residue fraction, although nutritionally difficult to justify, actually increased precision in the NE equations. Note that it is unfair to compare both NE formulas based on precision alone. An interesting follow-up question is to take accuracy also into account when comparing CVB and NRC.
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Li, Zhongchao, Zhiqian Lyu, Hu Liu, Dewen Liu, Neil Jaworski, Yakui Li, and Changhua Lai. "Prediction of net energy values in expeller-pressed and solvent-extracted rapeseed meal for growing pigs." Animal Bioscience 34, no. 1 (January 1, 2021): 109–18. http://dx.doi.org/10.5713/ajas.19.0962.
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Objective: The objective of this study was to determine net energy (NE) of expeller-press (EP-RSM) and solvent-extracted rapeseed meal (SE-RSM) and to establish equations for predicting the NE in rapeseed meal (RSM) fed to growing pigs.Methods: Thirty-six barrows (initial body weight [BW], 41.1±2.2 kg) were allotted into 6 diets comprising a corn-soybean meal basal diet and 5 diets containing 19.50% RSM added at the expense of corn and soybean meal. The experiment had 6 periods and 6 replicate pigs per diet. During each period, the pigs were individually housed in metabolism crates for 16 days which included 7 days for adaption to diets. On day 8, pigs were transferred to respiration chambers and fed their respective diet at 2,000 kJ metabolizable energy (ME)/kg BW<sup>0.6</sup>/d. Feces and urine were collected, and daily heat production was measured from day 9 to 13. On days 14 and 15, the pigs were fed at 890 kJ ME/kg BW<sup>0.6</sup>/d and fasted on day 16 for evaluation of fasting heat production (FHP).Results: The FHP of pigs averaged 790 kJ/kg BW<sup>0.6</sup>/d and was not affected by the diet composition. The NE values were 10.80 and 8.45 MJ/kg DM for EP-RSM and SE-RSM, respectively. The NE value was positively correlated with gross energy (GE), digestible energy (DE), ME, and ether extract (EE). The best fit equation for NE of RSM was NE (MJ/kg DM) = 1.14×DE (MJ/kg DM)+0.46×crude protein (% of DM)–25.24 (n = 8, R<sup>2</sup> = 0.96, p<0.01). The equation NE (MJ/kg DM) = 0.22×EE (% of DM)–0.79×ash (% of DM)+14.36 (n = 8, R<sup>2</sup> = 0.77, p = 0.018) may be utilized to quickly determine the NE in RSM when DE or ME values are unavailable.Conclusion: The NE values of EP-RSM and SE-RSM were 10.80 and 8.45 MJ/kg DM. The NE value of RSM can be well predicted based on energy content (GE, DE, and ME) and proximate analysis.
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Cao, Shengkui, Guangchao Cao, Kelong Chen, Guangzhao Han, Ying Liu, Yufan Yang, and Xiaodong Li. "Characteristics of CO2, water vapor, and energy exchanges at a headwater wetland ecosystem of the Qinghai Lake." Canadian Journal of Soil Science 99, no. 3 (September 1, 2019): 227–43. http://dx.doi.org/10.1139/cjss-2018-0104.
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Ecosystem carbon dioxide (CO2), water vapor, and heat exchanges in alpine wetlands on the Qinghai–Tibetan Plateau are not comprehensively understood. Thus, we studied variability of net ecosystem CO2 exchange (NEE), ecosystem respiration (Re), gross primary production (GPP), evapotranspiration (ET), and heat fluxes over a headwater wetland ecosystem in the Qinghai Lake region. Results showed that the headwater wetland ecosystem was net CO2 absorption on the annual scale, in which monthly NEE, GPP, and Re in two consecutive years varied from −165.16 to 93 g CO2 m−2 mo−1, 6.66 to 384.45 g CO2 m−2 mo−1, and 6.9 to 232.02 g CO2 m−2 mo−1, respectively. The monthly ET from June to September was smaller than precipitation; these results reversed in the remaining months. Annual ET was 362.1 mm in 2015 and 324.96 mm in 2016. The net radiation (Rn), sensible heat (H), latent heat (LE), and ground heat (G) fluxes showed similar monthly patterns. Values of monthly average half-hour Rn, H, LE, and G at the daytime showed Rn > LE > H > G, and the time of the monthly half-hour G peak obviously lagged the Rn, H, and LE. Monthly average Bowen ratios were <1 from May to October, but it reversed in the rest of the months.
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Lohrenz, John. "Net Values of Our Information (includes associated papers 18563 and 18580 )." Journal of Petroleum Technology 40, no. 04 (April 1, 1988): 499–503. http://dx.doi.org/10.2118/16842-pa.
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Zivic, Marija, Antun Galovic, and Zdravko Virag. "Detailed analysis of the effect of the turbine and compressor isentropic efficiency on the thermal and exergy efficiency of a Brayton cycle." Thermal Science 18, no. 3 (2014): 843–52. http://dx.doi.org/10.2298/tsci1403843z.
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Energy and exergy analysis of a Brayton cycle with an ideal gas is given. The irreversibility of the adiabatic processes in turbine and compressor is taken into account through their isentropic efficiencies. The net work per cycle, the thermal efficiency and the two exergy efficiencies are expressed as functions of the four dimensionless variables: the isentropic efficiencies of turbine and compressor, the pressure ratio, and the temperature ratio. It is shown that the maximal values of the net work per cycle, the thermal and the exergy efficiency are achieved when the isentropic efficiencies and temperature ratio are as high as possible, while the different values of pressure ratio that maximize the net work per cycle, the thermal and the exergy efficiencies exist. These pressure ratios increase with the increase of the temperature ratio and the isentropic efficiency of compressor and turbine. The increase of the turbine isentropic efficiency has a greater impact on the increase of the net work per cycle and the thermal efficiency of a Brayton cycle than the same increase of compressor isentropic efficiency. Finally, two goal functions are proposed for thermodynamic optimization of a Brayton cycle for given values of the temperature ratio and the compressor and turbine isentropic efficiencies. The first maximizes the sum of the net work per cycle and thermal efficiency while the second the net work per cycle and exergy efficiency. In both cases the optimal pressure ratio is closer to the pressure ratio that maximizes the net work per cycle.
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Okine, E. K., D. H. McCartney, and J. B. Basarab. "Evaluation of the National Research Council (NRC) nutrient requirements for beef cattle: Predicting feedlot performance." Canadian Journal of Animal Science 83, no. 4 (December 1, 2003): 787–92. http://dx.doi.org/10.4141/a03-009.
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The accuracy of predicted CowBytes® versus actual dry matter intake (DMI) and average daily gain (ADG) of 407 Hereford × Angus and Charolais × Maine Anjou (445.6 ± 36 kg) feeder cattle using digestable enery acid detergent fiber (DE) estimated from the (ADF) content [Laboratory analysis method (LAB)] and from values determined in vivo (INVIVO method) was examined. The diet consisted of a 73.3% concentrate diet, 22.0% barley silage, 1.6% molasses, and 3.1% feedlot supplement fed ad libitum (as-fed basis). The calculated DE values of the feed were used to predict the metabolizable energy (ME), net energy of maintenance (NEm), and net energy of gain (NEg) of the diet. These energy values were then used in CowBytes® to predict dry matter intake (DMI), ADG, and days on feed (DOF) necessary to meet targeted quality grade of AA and weights of 522 and 568 kg for the heifers and steers, respectively. There was no effect of gender and prediction method interaction (P > 0.10) on any of the variables measured. There were no (P > 0.05) differences in predicted DMI by either the INVIVO or LAB method but both methods underestimated DMI actually consumed by the cattle by 6.8 and 4.9% (P = 0.007), respectively. Indeed, regression values from these predictive methods and actual DMI were (P < 0.05) different from the one-to-one relationship expected by definition. In spite of the higher actual DMI, the actual ADG of the cattle was 14 and 11% (P = 0.0004) lower than was predicted by either the INVIVO or LAB methods. A possible reason for the lower ADG could be an overestimation of DE of the diet. Thus, if available, users of CowBytes® should use actual DMI from their experience in ration formulation. In addition, the effects of environmental temperature on digestibility of diets should be taken into consideration when using the DE of the diet as determined from in vivo digestibility trials or calculated from chemical analyses in determining the DMI of feedlot cattle. Key words: Beef cattle, performance, CowBytes®, National Research Council
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MacLean, W. C. "Use of the net metabolizable energy values for labeling of infant formulas and foods—potential issues." Journal of Food Composition and Analysis 18, no. 2-3 (March 2005): 223–39. http://dx.doi.org/10.1016/j.jfca.2003.10.006.
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Tooze, Zena J., and Clifton Lee Gass. "Responses of rufous hummingbirds to midday fasts." Canadian Journal of Zoology 63, no. 10 (October 1, 1985): 2249–53. http://dx.doi.org/10.1139/z85-333.
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This study investigates how rufous hummingbirds regain energy balance after experimentally imposed midday fasts reduce their energy reserves. Net energy balance calculated from food intake, activity budgets, and allometric equations for the costs of flying and perching was highly correlated with change in body weight in laboratory tests of 3 h or more. Individuals accumulated energy and body weight at the same rate after fasts as before, resulting in energy deficits at the end of the day compared with control conditions. Energy balance relative to control values was regained by the following morning, primarily by reducing metabolic costs in the dark through torpor. Net energy intake increased the following day, but this increase was relatively unimportant to reestablishing equilibrium.
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Moitzi, Gerhard, Reinhard W. Neugschwandtner, Hans-Peter Kaul, and Helmut Wagentristl. "Effect of tillage systems on energy input and energy efficiency for sugar beet and soybean under Pannonian climate conditions." Plant, Soil and Environment 67, No. 3 (March 1, 2021): 137–46. http://dx.doi.org/10.17221/615/2020-pse.
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Sustainable cropping systems require efficient usage of fossil energy. This study performed on a long-term field experiment in the Pannonian Basis investigated the energy efficiency of four tillage systems (mouldboard plough (MP), deep conservation tillage (CT<sub>d</sub>), shallow conservation tillage (CT<sub>s</sub>) and no-tillage (NT)) for sugar beet and soybean production, taking fuel consumption, total energy input (made up of both direct and indirect inputs), crop yield, energy output, net-energy output, energy intensity and energy use efficiency into account. The input rates of fertiliser, chemical plant protection, and seeds were set constant across years; whereas measured values of fuel consumption were used for all tillage treatments. NT required a considerably lower energy input than MP and CT<sub>d</sub> as no fuel is needed for tillage and just slightly more fuel for additional spraying of glyphosate. Anyhow, the energy efficiency parameters did not differ between tillage treatments, as theses parameters were mainly determined by energy output, which was considerably higher than the energy input. However, year effects on the energy efficiency were observed for both crops. Nitrogen fertilisation and diesel fuel consumption were identified as the most energy-intensive inputs. Consequently, the energy input for sugar beet was higher than that for soybean, which was identified as a low-input crop. But sugar beet attained a more than 4 times higher net-energy output, a 2.5 times higher energy use efficiency, and an energy intensity for yield production of less than 3 times those of soybean.
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Rustamov, Anar. "Energy dependence of strangeness production and event-byevent fluctuations." EPJ Web of Conferences 171 (2018): 02003. http://dx.doi.org/10.1051/epjconf/201817102003.
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We review the energy dependence of strangeness production in nucleus-nucleus collisions and contrast it with the experimental observations in pp and p-A collisions at LHC energies as a function of the charged particle multiplicities. For the high multiplicity final states the results from pp and p-Pb reactions systematically approach the values obtained from Pb-Pb collisions. In statistical models this implies an approach to the thermodynamic limit, where differences of mean multiplicities between various formalisms, such as Canonical and Grand Canonical Ensembles, vanish. Furthermore, we report on event-by-event net-proton fluctuations as measured by STAR at RHIC/BNL and by ALICE at LHC/CERN and discuss various non-dynamical contributions to these measurements, which should be properly subtracted before comparison to theoretical calculations on dynamical net-baryon fluctuations.
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Margan, DE, NM Graham, and TW Searle. "Energy values of whole lucerne (Medicago sativa) and of its stem and leaf fractions in immature and fully grown sheep." Australian Journal of Experimental Agriculture 25, no. 4 (1985): 783. http://dx.doi.org/10.1071/ea9850783.
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Chopped lucerne hay (Medicago sativa) and a stem fraction derived from it were fed to two adult and two immature wethers ad libitum and at a level near maintenance. Energy, nitrogen, and carbon balances were measured during feeding and fasting. The hay contained 17% crude protein and 46% cell wall constituents (dry matter basis) and the stem, which was 53% of the total, contained 10% crude protein and 64% cell wall. Voluntary dry matter consumption rates of the hay (per kg 3/4) were 103 and 145 g/day by the adults and immatures, respectively; the corresponding values for the stem were 73 and 100 g/day. Maximum daily energy balances were 290-3 16 kJ/kg3/4 for the hay and approximately maintenance for the stem. With both ad libitum and restricted feeding, energy digestibility was higher for the hay (56- 63%) than for the stem fraction (45-51%). The metabolizable fraction of digestible energy was 78% at the low and 82% at the high level of feeding and tended to be greater with the stem than with the hay. At the lower feed intake, metabolizable energy was about 10 and 8 MJ/kg organic matter for whole lucerne and stem respectively. Net availability of metabolizable energy was 64 and 49% for maintenance and gain on the hay, compared with 53 and 34% on the stem. As estimated by difference, the energy values of leaf were: digestible energy, 76%; metabolizable energy, 77% of digestible energy or 12.4 MJ/kg organic matter; net availability of metabolizable energy, 78% for maintenance and 60% for gain. All these figures are for the adult sheep; the immature animals gave values that were lower to various degrees. Consideration of the present results together with published data for other samples of lucerne suggests that the use of equations based on study of grasses to predict the energy values of lucerne is likely to introduce significant bias. Equations for this limited set of data on lucerne are given, gross energy being related to crude protein content, metabolizable energy to crude fibre and net availability of metabolizable energy to metabolizable energy content.
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Homolka, P., V. Koukolová, M. Podsedníček, and A. Hlaváčková. " Nutritive value of red clover and lucerne forages for ruminants estimated by in vitro and in vivo digestibility methods." Czech Journal of Animal Science 57, No. 10 (October 12, 2012): 454–68. http://dx.doi.org/10.17221/6346-cjas.
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The aim of this study was to determine the nutrient and energy levels of red clover and lucerne forage. Investigation of forage at different maturity stages of three growths was carried out by chemical analysis, in vitro and in vivo digestibility methods. Generally, maturation caused a significant increase in fibre fractions. With the increasing maturity of forage samples the in vivo, in vitro, and calculated in vivo (in vivo<sub>calcul</sub>) digestibilities of organic matter (OM) linearly decreased. The in vitro and in vivo<sub>calcul</sub> digestibilities of OM averaged 0.754 and 0.708 for red clover and 0.717 and 0.667 for lucerne, respectively. The in vivo OM digestibility averaged 0.710 for red clover and 0.666 for lucerne. Gross energy (GE), digestible energy (DE), metabolizable energy (ME), net energy for lactation (NEL), and net energy for growth (NEG) averaged 18.12, 12.41, 9.60, 5.67, 5.50 and 18.09, 11.56, 9.01, 5.26, 4.99 MJ/kg of dry matter for red clover and lucerne, respectively. The effect of a vegetative stage on energy values of both forages was diverged for various growth times. When data were pooled across the estimated season, seven cutting-specific equations for descriptions of GE, DE, ME, NEL, NEG, in vitro, and in vivo OM digestibilities were obtained for red clover and lucerne, separately. The red clover model expression gave similar prediction equations for lucerne. It was possible to predict cutting-specific equations with coefficients of determination R<sup>2</sup> > 0.719 for red clover and R<sup>2</sup> > 0.400 for lucerne of the variation in GE, DE, ME, NEL, and NEG. The in vitro and in vivo OM digestibility equations were predicted with R<sup>2 </sup>being 0.840 (in vitro) and 0.707 (in vivo) for red clover, and 0.979 (in vitro) and 0.937 (in vivo) for lucerne. The parameters of these specific equations were statistically preferable than the general model expression which included both forages together.
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Almeida, Vitor Visintin Silva de, Augusto César de Queiroz, Fabiano Ferreira da Silva, Robério Rodrigues Silva, Aline Cardoso Oliveira, and Danilo Ribeiro de Souza. "Body composition and energy and protein requirements of grazing Nelore steers." Revista Brasileira de Zootecnia 38, no. 7 (July 2009): 1347–54. http://dx.doi.org/10.1590/s1516-35982009000700026.
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This experimentwas carried out with the objective of determining the energy and protein requirements of grazing Nellore steers. Twenty four Nellore steers (average 371 ± 14 kg of BW and 26 months old) were used. Four steers were slaughtered at the beginning of the experiment (reference group), serving as a reference for the subsequent study. The remaining 20 animals were weighed and distributed in a randomized complete block design with four levels of supplementation offers: 0.0 (mineral mixture - control), 0.3, 0.6 and 0.9% BW, with five replications. The supplements, based on ground corn, soybean meal and/or urea, were previously balanced to achieve an average daily gain of 350, 650 and 850g, respectively, for the different levels of supplementation offers. The protein, fat and energy contents retained in the animal body were determined by regression equations of the logarithm of the protein, fat and energy in the animal body contents, in function of the logarithm of empty body weight (EBW). Net requirements of protein and energy for a gain of 1kg of EBW were obtained by deriving the prediction equations of the animal body content of protein, fat, or energy in function of the EBW logarithm. The net energy requirements for weight gain of Nellore steer can be obtained by the equation: NEg = 0.05764 × EBW0,75 × DEBWG0.8328. The following equation was obtained to estimate the retained protein (RP), in function of the average daily gain (ADG) and retained energy (RE): RP = 28.9199 + 85.7301 FBWG + 8.0669 RE. The net protein requirement for Nellore steers decreased as the body weight increased, with values of 174.62 and 163.10 g/kg EBG for animals of 300 and 450 kg BW, respectively.
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Robinson, P. H. "A new look at energy discounts: using published studies to calculate discounted net energy values for dairy cows fed ad libitum." Canadian Journal of Animal Science 87, no. 1 (March 1, 2007): 57–70. http://dx.doi.org/10.4141/a06-030.
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Correct assessment of the energetic density of a diet fed to dairy cows is fundamental to accurate prediction of performance. Feeding experiments using lactating Holstein cows fed ad libitum, as reported by North American research facilities in peer-reviewed publications since 1990 in which the actual NEl density of the diet could be calculated from performance, and three dietary energy prediction systems [i.e., NRC (1989), NRC (2001) and an approach developed at the University of California at Davis (UCD)] were used to determine if the NEl discount (i.e., depression) in diets above maintenance (M) energy intake (i.e., 1 ×M) is linear or curvilinear. The principle used was that the expected NEl of the diets could be estimated using the three systems (at 3 ×M ), as well as the NEl calculated from observed performance of the cows, and the deviation (or difference) between the actual and estimated dietary NEl density could be regressed against the actual NEl output (×M) to determine the form of the expected decline in the NEl density of the diet as the energy output (relative to maintenance energy intake) of the cows increased. Results show that output of NEl (×M) is not a predictor of the deviation of the actually calculated NEl level of the diet vs. that estimated by any system. This was unexpected, as all three NEl estimation systems presume a linear decline in the deviation as level of NEl output (×M) increases. In contrast to NEl output (×M), intake of DM (g kg-1 body weight) was a weak predictor (r2 = 0.36 to 0.39 depending on system) of the diet NEl density deviation. The best predictors of diet NEl deviation in all three systems were DM intake (g kg-1BW) and NEl output (×M) combined, where r2 values were much higher (0.76 to 0.79), and there was little evidence of prediction bias in any system. Results suggest that the NEl density of a diet is a function of the inherent characteristics of the diet (i.e., its intrinsic digestibility), its level of consumption, and the genetic merit (and/or stage of lactation ) of the cows that eat it. The lack of a relationship between the deviation of the actually calculated vs. predicted NEl concentration shows that the three NEl prediction equations examined are fundamentally incorrect in their assumption that the NEl concentration of diets declines as the NEl output (×M) of the cows consuming them increases. However, the inaccurate estimates of the actual NEl densities by the systems can be corrected by application of appropriate equations that consider the anticipated level of DM intake and NEl output. Key words: Discount, net energy for lactation
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Valaja, Jarmo, and Hilkka Siljander-Rasi. "Effect of dietary crude protein and energy content on nitrogen utilisation, water intake and urinary output in growing pigs." Agricultural and Food Science 7, no. 3 (January 1, 1998): 381–90. http://dx.doi.org/10.23986/afsci.72869.
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A digestibility and balance trial was carried out with four intact castrated male pigs (live weight 33-82 kg) to study the effects of dietary crude protein and energy content on nutrient digestibility, nitrogen metabolism, water intake and urinary output. In a 4 x 4 Latin square design, four barley-oats-soya bean meal based diets were arranged 2x2 factorially. The corresponding factors were dietary crude protein (CP) content: high (180 g/kg CP) or low protein diet (140 g/kg CP) supplemented with free lysine, methionine and threonine; and dietary net energy content; high (1.05 feed units (FU)/kg) (feed unit=9.3 MJ net energy) or low net energy content (0.95 FU/kg). Lowering dietary CP content (mean values of 189 to 152 g/kg dry matter, respectively) by supplementation of free amino acids decreased urinary nitrogen (N) excretion by 6.9 g/day (32%) (P
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Hussein, Maged M. A. "Mean Daily Variability of Energy Fluxes Above Alexandria Eastern Harbor." ATHENS JOURNAL OF SCIENCES 8, no. 3 (August 30, 2021): 183–98. http://dx.doi.org/10.30958/ajs.8-3-2.
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Mean daily variability of latent heat (E), sensible heat (H), net long wave (Lwnet), net short wave, and net flux of surface heat balance were estimated from hourly sea surface water temperature (SST) and meteorological time series obtained for three months during summer season (2019) in Alexandria Eastern Harbor (AEH), Egypt. Latent and sensible heat were not in phase and had their maximum 181.12 W/m2 (5:00 PM), 16.5 W/m2 (5:00 AM) and minimum 103.64 W/m2 (8:00 AM), -12.14 W/m2 (3:00 PM), resulting in Bowen ration of -0.11 and 0.09, respectively. The loss of heat by evaporation therefore predominates than sensible heat utilized to warm surface atmosphere. The instability of the atmosphere was existing nearly most of the time period, rising exchange coefficients of sensible and latent heat flux by about 24.26% over estimated neutral values (from 1.15 × 10−3 to 1.43 × 10−3). Mean Lwnet changed from 165.63 at early morning to 173.52 W/m2 at late afternoon, point out its significant importance in the total balance of heat flux of eastern harbor surface. Latent heat flux and Lwnet were positive (energy losing from eastern harbor), throughout the day. The daily average of net energy budget (S) was 38.52 W/m2; daytime gain exceeded nighttime loss, with consequent heating the eastern harbor. Qualitatively, daily variations of net energy budget (S) were nearly consistent with time delay to the variability of sea surface temperature, indicating the predominant role of the heat budget of the surface layer in modulating surface temperatures of the Eastern Harbor. Keywords: heat flux, shortwave, long wave, latent heat, sensible heat, Eastern Harbor
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Oltjen, James W. "How did Lofgreen and Garrett do the math?" Translational Animal Science 3, no. 3 (June 1, 2019): 1011–17. http://dx.doi.org/10.1093/tas/txz072.
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Abstract Lofgreen and Garrett introduced a new system for predicting growing and finishing beef cattle energy requirements and feed values using net energy concepts. Based on data from comparative slaughter experiments they mathematically derived the California Net Energy System. Scaling values to body weight to the ¾ power, they summarized metabolizable energy intake (ME), energy retained (energy balance [EB]), and heat production (HP) data. They regressed the logarithm of HP on ME and extended the line to zero intake, and estimated fasting HP at 0.077 Mcal/kg0.75, similar to previous estimates. They found no significant difference in fasting HP between steers and heifers. Above maintenance, however, a logarithmic fit of EB on ME does not allow for increased EB once ME is greater than 340 kcal/kg0.75, or about three times maintenance intake. So based on their previous work, they used a linear fit so that partial efficiency of gain above maintenance was constant for a given feed. They show that with increasing roughage level efficiency of gain (slope) decreases, consistent with increasing efficiency of gain and maintenance with greater metabolizable energy of the feed. Making the system useful required that gain in body weight be related to EB. They settled on a parabolic equation, with significant differences between steers and heifers. Lofgreen and Garrett also used data from a number of experiments to relate ME and EB to estimate the ME required for maintenance (ME = HP) and then related the amount of feed that provided that amount of ME to the metabolizable energy content of the feed (MEc), resulting in a logarithmic equation. Then they related that amount of feed to the net energy for gain calculated as the slope of the EB line when regressed against feed intake. Combining the two equations, they estimate the net energy for maintenance and gain per unit feed (Mcal/kg dry matter) as a function of MEc: 0.4258 × 1.663MEc and 2.544–5.670 × 0.6012MEc, respectively. Finally, they show how to calculate net energy for maintenance and gain from experiments where two levels of a ration are fed and EB measured, where one level is fed and a metabolism trial is conducted, or when just a metabolism trial is conducted—but results are not consistent between designs.
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ATALAY, Hasan, and Fatih KAHRIMAN. "Estimation of relative feed value, relative forage quality and net energy lactation values of some roughage samples by using near infrared reflectance spectroscopy." Journal of Istanbul Veterinary Sciences 4, no. 3 (December 30, 2020): 109–18. http://dx.doi.org/10.30704/http-www-jivs-net.791669.
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Torreiro, Yarima, Leticia Pérez, Gonzalo Piñeiro, Francisco Pedras, and Angela Rodríguez-Abalde. "The Role of Energy Valuation of Agroforestry Biomass on the Circular Economy." Energies 13, no. 10 (May 15, 2020): 2516. http://dx.doi.org/10.3390/en13102516.
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The use of biomass has increased significantly in recent years. In this context, the use of not valued high-potential biomass (NVHPB) is emerging as a suitable alternative. This is the case of pruning vine, pruning kiwi, scrub (heather, gorse, broom) and forest pruning. The objective of this research was to study the potential of six selected agroforestry biomasses as biofuels in thermochemical processes. For that purpose, biomass was collected by specific machinery. Proximate and ultimate analyses were carried out as well as the inorganic compounds’ determination. Then, natural and forced drying were conducted. Low heating values (LHV) between 17 and 20 MJ/kg (dry basis) were achieved in all analyzed cases. Granulometric reduction, biomass classification and densification took place. Finally, energy recovery tests through microcogeneration were carried out. Values close to 97% in cogeneration efficiency were reached (9% net electric yield and 88% thermal yield), offering an alternative to obtain clean energy.
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Ali, Bushra, Shaista Khan, and Shakeel Ahmad. "Contributions of Jets in Net Charge Fluctuations from the Beam Energy Scan at RHIC and LHC." Advances in High Energy Physics 2019 (July 14, 2019): 1–14. http://dx.doi.org/10.1155/2019/6034981.
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Dynamical net charge fluctuations have been studied in ultrarelativistic heavy-ion collisions from the beam energy scan at RHIC and LHC energies by carrying out the hadronic model simulation. Monte Carlo model, HIJING, is used to generate events in two different modes, HIJING-default with jet quenching switched off and jet/minijet production switched off. A popular variable, ν[+-,dyn], is used to study the net charge fluctuations in different centrality bins and the findings are compared with the available experimental values reported earlier. Although the broad features of net charge fluctuations are reproduced by the HIJING, the model predicts the larger magnitude of fluctuations as compared to the one observed in experiments. The role of jets/minijets production in reducing the net charge fluctuations is, however, distinctly visible from the analysis of the two types of HIJING events. Furthermore, dNch/dη and 1/N scaling is partially exhibited, which is due to the fact that, in HIJING, nucleus-nucleus collisions are treated as multiple independent nucleon-nucleon collisions.
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Andersen, Niels G., and Jorgen Riis-Vestergaard. "Alternative model structures for bioenergetics budgets of a cruising predatory gadoid: incorporating estimates of food conversion and costs of locomotion." Canadian Journal of Fisheries and Aquatic Sciences 61, no. 12 (December 1, 2004): 2413–24. http://dx.doi.org/10.1139/f04-153.
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Swimming costs of North Sea saithe (pollock) (Pollachius virens) were estimated from a balanced energy budget equation using field estimates of food ration and growth together with two alternative food conversion functions. Food ration estimates were obtained by application of a gastric evacuation model to field data on amount and composition of stomach contents. Laboratory-based net conversion efficiency, κlab, produced values of 1.616.72 of the activity multiplier, whereas estimates of 1.443.27 were obtained from application of an activity-modulated net conversion efficiency, κwild. The activity multiplier ranged from 2.0 to 2.5 at optimum cruising speed. The high activity levels obtained by application of κlab probably reflect low-cost accumulation of lipid in laboratory saithe. All together, the results indicated that net conversion efficiency in North Sea saithe was better described by κwild (ranging from 0.43 to 0.50) as opposed to κlab (0.510.76). Model estimates of food ration and body growth using activity costs at optimum cruising speed further demonstrated the sensitivity of estimates from the balanced energy budget equations to applied parameter values and field estimates of variables.
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Leskinen, Niina, Jussi Vimpari, and Seppo Junnila. "The impact of renewable on-site energy production on property values." Journal of European Real Estate Research 13, no. 3 (April 20, 2020): 337–56. http://dx.doi.org/10.1108/jerer-11-2019-0041.
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Purpose Contrary to the traditional technology project perspective, real estate investors see building-specific renewable energy (on-site energy) investments as part of the property and as something affecting the property’s ability to produce a (net) cash flow. This paper aims to show the value-influencing mechanism of on-site energy production from a professional property investors’ perspective. Design/methodology/approach The value-influencing mechanism is presented with a case study of a prime logistics property located in the Helsinki metropolitan area, Finland. The case study results are compared with the results of a survey answered by over 70 property valuation professionals in the Finnish real estate market. Findings Current valuation practice supports the presented value-creation mechanism based on the capitalisation of the savings generated by a building’s own energy production. Valuation professionals see benefits beyond decreased operating expenses such as enhanced image and better saleability. However, valuers acted more conservatively than expected when transferring these additional benefits to the cash flows of the case property. Practical implications Because the savings in operating expenses can be capitalised into the property value, property investors should consider on-site energy production when the return of on-site energy exceeds the return of the property. This enhances the profitability of on-site energy, especially in urban areas with low initial yields. Originality/value This is the first research paper to open the value-influencing mechanism of on-site energy production from a professional property investors’ perspective in commercial properties and to confirm it from a market study.