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Maintenance Requirements (maintenance + requirement)
Selected AbstractsLysine requirement studies in modern genotype barrows dependent on age, protein deposition and dietary lysine efficiencyJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3 2009C. Wecke Summary N balance experiments were conducted to derive age-dependent model parameters for modelling of lysine (Lys) requirements in growing pigs. Modern genotype barrows from 16 litters were utilized (four piglets/litter) at 15, 30, 50, 70, 90 and 110 kg body weight respectively. Six diets provided graded dietary protein supply (40 to 320 g/kg) by a constant mixture of barley, wheat, potato protein, wheat gluten, soybean protein concentrate and crystalline amino acids. Lys was set as the first limiting dietary amino acid. Each age period provided 24 N balance data (n = 4) to derive N maintenance requirement (NMR) and theoretical maximum for daily N retention (NRmaxT) by non-linear regression analysis. At high dietary Lys efficiency, 17,18 g daily Lys intake was required for 170 g daily protein deposition. To achieve similar daily protein deposition, pigs need 21,23 g Lys if the Lys efficiency is 20% lower. For higher daily protein deposition (195,200 g) and varying dietary Lys efficiency, between 22 and 29 g Lys was required. The Lys requirement data yielded by modelling were in line with current recommendations. Further developments of the approach are discussed to improve age-independent applications. [source] A hybrid model of anaerobic E. coli GJT001: Combination of elementary flux modes and cybernetic variablesBIOTECHNOLOGY PROGRESS, Issue 5 2008Jin Il Kim Flux balance analysis (FBA) in combination with the decomposition of metabolic networks into elementary modes has provided a route to modeling cellular metabolism. It is dependent, however, on the availability of external fluxes such as substrate uptake or growth rate before estimates can become available of intracellular fluxes. The framework classically does not allow modeling of metabolic regulation or the formulation of dynamic models except through dynamic measurement of external fluxes. The cybernetic modeling approach of Ramkrishna and coworkers provides a dynamic framework for modeling metabolic systems because of its focus on describing regulatory processes based on cybernetic arguments and hence has the capacity to describe both external and internal fluxes. In this article, we explore the alternative of developing hybrid models combining cybernetic models for the external fluxes with the flux balance approach for estimation of the internal fluxes. The approach has the merit of the simplicity of the early cybernetic models and hence computationally facile while also providing detailed information on intracellular fluxes. The hybrid model of this article is based on elementary mode decomposition of the metabolic network. The uptake rates for the various elementary modes are combined using global cybernetic variables based on maximizing substrate uptake rates. Estimation of intracellular metabolism is based on its stoichiometric coupling with the external fluxes under the assumption of (pseudo-) steady state conditions. The set of parameters of the hybrid model was estimated with the aid of nonlinear optimization routine, by fitting simulations with dynamic experimental data on concentrations of biomass, substrate, and fermentation products. The hybrid model estimations were tested with FBA (based on measured substrate uptake rate) for two different metabolic networks (one is a reduced network which fixes ATP contribution to the biomass and maintenance requirement of ATP, and the other network is a more complex network which has a separate reaction for maintenance.) for the same experiment involving anaerobic growth of E. coli GJT001. The hybrid model estimated glucose consumption and all fermentation byproducts to better than 10%. The FBA makes similar estimations of fermentation products, however, with the exception of succinate. The simulation results show that the global cybernetic variables alone can regulate the metabolic reactions obtaining a very satisfactory fit to the measured fermentation byproducts. In view of the hybrid model's ability to predict biomass growth and fermentation byproducts of anaerobic E. coli GJT001, this reduced order model offers a computationally efficient alternative to more detailed models of metabolism and hence useful for the simulation of bioreactors. [source] Comparative response analysis of conventional and innovative seismic protection strategiesEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 5 2002S. Bruno Abstract The paper presents a numerical investigation aimed at evaluating the improvements achievable through devices for passive seismic protection of buildings based on the use of shape memory alloys (SMA) in place of conventional steel or rubber devices. To get some generality in the results, different resisting reinforced concrete plane frames were analysed, either protected or not. ,New' and ,existing' buildings were considered depending on whether seismic provisions are adopted in the building design or not. Base isolation and energy dissipation were equally addressed for both conventional and innovative SMA-based devices. Fragility analyses were performed using specific damage measures to account for comparisons among different damage types; the results were then used to estimate quantitatively the effectiveness of the various protection systems. More specifically, the assessment involved a direct comparison of the damage reduction provided by each protection system with respect to the severe degradation experienced by the corresponding non-protected frame. Structural damage, non-structural damage and damage to contents were used on purpose and included in a subsequent phase of cost analysis to evaluate the expected gains also in terms of economic benefits and life loss prevention. The results indicate that base isolation, when applicable, provides higher degrees of safety than energy dissipation does; moreover, the use of SMA-based devices generally brings about better performances, also in consideration of the reduced functional and maintenance requirements. Copyright © 2002 John Wiley & Sons, Ltd. [source] Growth and chemical composition of wild oat (Avena fatua) under Mediterranean conditionsGRASS & FORAGE SCIENCE, Issue 1 2004M. K. J. El-Shatnawi Abstract Wild oat (Avena fatua) is an annual cool-season species that grows in areas with a Mediterranean climate and has potential as a forage source in Jordan. A field experiment was conducted during the growing seasons of 1999,2000 and 2000,2001 under sub-humid Mediterranean conditions at Samta in the Ajloun Mountains, Jordan. Data on seasonal herbage mass, morphology and chemical composition of wild oat were collected at 60, 80, 100, 120 and 140 days after emergence. Plant height increased rapidly beyond 100 days after emergence. The increase in herbage mass of dry matter was gradual and peaked at 140 days after emergence. The lowest concentration of crude fibre was at 60 and 80 days after emergence, with a range of 201,263 g kg,1 DM. Crude fibre concentrations (610,630 g kg,1 DM) peaked at 140 days after emergence (maturity). In contrast to concentrations of crude fibre, concentrations of crude protein decreased gradually with age. The calcium and phosphorus concentrations were sufficient to meet the maintenance requirements of ewes. [source] Bioprocesses for the removal of nitrogen oxides from polluted airJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2005Yaomin Jin Abstract Nitrogen oxides (NOx) of environmental concern are nitrogen monoxide (NO) and nitrogen dioxide (NO2). They are hazardous air pollutants that lead to the formation of acid rain and tropospheric ozone. Both pollutants are usually present simultaneously and are, therefore, called NOx. Another compound is N2O which is found in the stratosphere where it plays a role in the greenhouse effect. Concern for environmental and health issues coupled with stringent NOx emission standards generates a need for the development of efficient low-cost NOx abatement technologies. Under such circumstances, it becomes mandatory for each NOx-emitting industry or facility to opt for proper NOx control measures. Several techniques are available to control NOx emissions: selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR), adsorption, scrubbing, and biological methods. Each process offers specific advantages and limitations. Since bioprocesses present many advantages over conventional technologies for flue gas cleaning, a lot of interest has recently been shown for these processes. This article reviews the major characteristics of conventional non-biological technologies and recent advances in the biological removal of NOx from flue gases based on the catalytic activity of either eucaryotes or procaryotes, ie nitrification, denitrification, the use of microalgae, and a combined physicochemical and biological process (BioDeNOx). Relatively uncomplicated design and simple operation and maintenance requirements make biological removal a good option for the control of NOx emissions in stationary sources. Copyright © 2005 Society of Chemical Industry [source] Aviation fuel demand modelling in OECD and developing countries: impacts of fuel efficiencyOPEC ENERGY REVIEW, Issue 1 2009Mohammad Mazraati On the quest for reducing the fuel consumption per passenger per flight for economical and environmental reasons, commercial aircraft manufacturers are implementing new strategies for optimising aircraft performance by using new lighter and stronger materials and enhancing engines' efficiencies in terms of fuel consumption and maintenance requirements. With the rising and falling of economies, whether in the Organization for Economic Cooperation and Development (OECD) countries or other developing countries, the aviation industry has been affected by multiple factors such as passenger traffic, freight traffic, airport capacities and oil prices. Aircraft manufacturers have worked on improving the engine efficiency of their newly built airplanes (e.g. Airbus's A-380 and Boeing's B-787), and many airports in the world have increased the number of their runways to face the increasing demand for air traffic in the world. Aviation efficiency can also be achieved through better load management, which in return enables airliners to cope with higher oil prices or rising costs. Aviation fuel demand is modelled in OECD North America, Europe and Pacific regions and some selected developing countries. Price elasticities of fuel demand in all regions are low, while income elasticities are high. The elasticity of aviation fuel demand on passenger kilometre performed (PKP) is considerably low. One per cent increase in PKP leads to less than half a per cent increase in aviation fuel demand, confirming an ongoing fuel efficiency in aviation industry. [source] Energy and protein demands for optimal egg production including maintenance requirements of female tilapia Oreochromis niloticusAQUACULTURE RESEARCH, Issue 5 2010Ingrid Lupatsch Abstract The daily requirements of a spawning tilapia female are quantified from the sum of the requirements for maintenance plus production of eggs. The protein and energy requirements for maintenance and the cost of depositing energy and protein towards growth or gonadal products were determined by supplying feed at increasing levels from zero to the maximum intake. Comparative body composition analyses of the females in addition to the amount and the content of eggs enabled us to quantify the total energy and protein channelled into weight gain or alternatively into egg production. The amount of eggs produced increased with increasing feeding levels and ranged between 0.7 and 1.1 g eggs per kg,1 fish day,1. Regardless of feed allowance, the composition of eggs was similar and contained 235 mg protein and 10.5 kJ g,1 wet weight. In contrast, the whole body of tilapia contained 167 mg protein and 6.7 kJ g,1 on average. The energy requirement for maintenance was calculated to be 59.46 kJ × BW (kg)0.80 and 0.98 g × BW (kg)0.70 for digestible protein. The partial efficiency of producing gonads was 0.67 and 0.59 for digestible energy and digestible protein respectively. [source] | |||||||||||||