scholarly journals Parametres of energy crop biomass handling

2008 ◽  
Vol 53 (No. 4) ◽  
pp. 161-165 ◽  
Author(s):  
J. Souček ◽  
V. Kocánová ◽  
M. Novák
Keyword(s):  
Model Calculation ◽  
Field Measurements ◽  
Energy Crops ◽  
Operating Conditions ◽  
Energy Crop ◽  
Unit Costs ◽  
Bulk Weight ◽  
Crop Biomass

Energy crop handling can be performed with standard handling machinery equipped with suitable adaptors. The authors describe and compare various types of handling of wood and herb energy crops. The published results have been gained by field measurements in operating conditions and calculated on the basis of bulk weight. Particular handling variants are supplemented with rough values of unit costs obtained by model calculation.

Improved infrared temperature mapping of elastohydrodynamic contacts

2009 ◽  
Vol 223 (8) ◽  
pp. 1165-1177 ◽  
Author(s):  
T Reddyhoff ◽  
H A Spikes ◽  
A V Olver
Keyword(s):  
Effective Means ◽  
Field Measurements ◽  
Operating Conditions ◽  
Mapping Technique ◽  
Shear Stresses ◽  
Measured Temperature ◽  
Ir Camera ◽  
Full Field ◽  
Group I ◽  
Increased Sensitivity

An effective means of studying lubricant rheology within elastohydrodynamic contacts is by detailed mapping of the temperature of the fluid and the bounding surfaces within the lubricated contact area. In the current work, the experimental approach initially developed by Sanborn and Winer and then by Spikes et al., has been advanced to include a high specification infrared (IR) camera and microscope. Besides the instantaneous capture of full field measurements, this has the advantage of increased sensitivity and higher spatial resolution than previous systems used. The increased sensitivity enables a much larger range of testable operating conditions: namely lower loads, speeds, and reduced sliding. In addition, the range of test lubricants can be extended beyond high shearing traction fluids. These new possibilities have been used to investigate and compare the rheological properties of a range of lubricants: namely a group I and group II mineral oil, a polyalphaolephin (group IV), the traction fluid Santotrac 50, and 5P4E, a five-ring polyphenyl-ether. As expected, contact temperatures increased with lubricant refinement, for the mineral base oils tested. Using moving heat source theory, the measured temperature distributions were converted into maps showing rate of heat input into each surface, from which shear stresses were calculated. The technique could therefore be validated by integrating these shear stress maps, and comparing them with traction values obtained by direct measurement. Generally there was good agreement between the two approaches, with the only significant differences occurring for 5P4E, where the traction that was deduced from the temperature over-predicted the traction by roughly 15 per cent. Of the lubricants tested, Santotrac 50 showed the highest average traction over the contact; however, 5P4E showed the highest maximum traction. This observation is only possible using the IR mapping technique, and is obscured when measuring the traction directly. Both techniques showed the effect of shear heating causing a reduction in traction.

scholarly journals Water Use Efficiency and Stress Tolerance of the Potential Energy Crop Miscanthus lutarioriparius Grown on the Loess Plateau of China

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 544
Author(s):  
Xuhong Zhao ◽  
Lifang Kang ◽  
Qian Wang ◽  
Cong Lin ◽  
Wei Liu ◽  
...  
Keyword(s):  
Potential Energy ◽  
Water Use Efficiency ◽  
Water Use ◽  
Loess Plateau ◽  
Survival Rates ◽  
Energy Crops ◽  
Central China ◽  
Energy Crop ◽  
Miscanthus Lutarioriparius ◽  
Use Efficiency

As a potential energy crop with high biomass yield, Miscanthus lutarioriparius (M. lutarioriparius), endemic to the Long River Range in central China, needs to be investigated for its acclimation to stressful climatic and soil conditions often found on the marginal land. In this study, traits related to acclimation and yield, including survival rates, plant height (PH), stem diameter (SD), tiller number (TN), water use efficiency (WUE), and photosynthetic rates (A), were examined for 41 M. lutarioriparius populations that transplanted to the arid and cold Loess Plateau of China. The results showed that the average survival rate of M. lutarioriparius populations was only 4.16% over the first winter but the overwinter rate increased to 35.03% after the second winter, suggesting that plants having survived the first winter could have acclaimed to the low temperature. The strikingly high survival rates over the second winter were found to be 95.83% and 80.85%, respectively, for HG18 and HG39 populations. These populations might be especially valuable for the selection of energy crops for such an area. Those individuals surviving for the two consecutive winters showed significantly higher WUE than those measured after the first winter. The high WUE and low stomatal conductance (gs) observed in survived individuals could have been responsible for their acclimation to this new and harsh environment. A total of 61 individuals with productive growth traits and strong resistance to cold and drought were identified for further energy crop development. This study showed that the variation of M. lutarioriparius held great potential for developing energy crops following continuous field selection.

scholarly journals Flame stability limits of premixed low-swirl combustion

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879087 ◽  
Author(s):  
Yinli Xiao ◽  
Zhibo Cao ◽  
Changwu Wang
Keyword(s):  
Flow Field ◽  
Vortex Breakdown ◽  
Flame Structure ◽  
Field Measurements ◽  
Operating Conditions ◽  
Oh Radicals ◽  
Flame Stability ◽  
Atmospheric Conditions ◽  
Swirl Burner ◽  
Stability Limits

The objective of this study is to gain a fundamental understanding of the flow-field and flame behaviors associated with a low-swirl burner. A vane-type low-swirl burner with different swirl numbers has been developed. The velocity field measurements are carried out with particle image velocimetry. The basic flame structures are characterized using OH radicals measured by planar laser-induced fluorescence. Three combustion regimes of low-swirl flames are identified depending on the operating conditions. For the same low-swirl injector under atmospheric conditions, attached flame is first observed when the incoming velocity is too low to generate vortex breakdown. Then, W-shaped flame is formed above the burner at moderate incoming velocity. Bowl-shaped flame structure is formed as the mixture velocity increases until it extinct. Local extinction and relight zones are observed in the low-swirl flame. Flow-field features and flame stability limits are obtained for the present burner.

A Theoretical Model for Ship–Wave Impact Generated Sea Spray

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Shafiul Mintu ◽  
David Molyneux ◽  
Bruce Colbourne
Keyword(s):  
Theoretical Model ◽  
Field Measurements ◽  
Operating Conditions ◽  
Ship Motions ◽  
Wave Impact ◽  
Fishing Vessels ◽  
Semi Empirical ◽  
Wave Induced ◽  
Analytical Expressions ◽  
Ship Speed

Abstract Spray generated by ships traveling in cold oceans often leads to topside icing, which can be dangerous to vessels. Estimation of the spray flux is a first step in predicting icing accumulation. The amount of spray water, the duration of exposure to the spray, and the frequency at which the spray is generated are all important parameters in estimating the spray flux. Most existing spray flux formulae are based on field observations from small fishing vessels. They consider meteorological and oceanographic parameters but neglect the vessel behavior. Ship heave and pitch motions, together with ship speed, determine the frequency of spray events. Thus, the existing formulae are not generally applicable to different sizes and types of vessels. This paper develops simple methods to quantify spray properties in terms that can be applied to vessels of any size or type. Formulae to estimate water content and spray duration are derived based on principles of energy conservation and dimensional analysis. To estimate spray frequency considering ship motions, a theoretical model is proposed. The model inputs are restricted to ship’s principal particulars, operating conditions, and environmental conditions. Wave-induced motions are estimated using semi-empirical analytical expressions. A novel spray threshold is developed to separate deck wetness frequency from spray frequency. Spray flux estimates are validated against full-scale field measurements available in the open literature with reasonable agreement.

Ship-Wave Impact Generated Sea Spray: Part 2 — Formulating Spray Frequency

2020 ◽  
Author(s):  
Shafiul A. Mintu ◽  
David Molyneux ◽  
Bruce Colbourne
Keyword(s):  
Field Measurements ◽  
Operating Conditions ◽  
Sea Spray ◽  
Ship Motions ◽  
Empirical Formulas ◽  
Wave Impact ◽  
Quick Estimate ◽  
Semi Empirical ◽  
Wave Induced ◽  
Analytical Expressions

Abstract In certain, but not all, circumstances a cloud of spray forms after a wave impacts a ship. The frequency of spray events affects the icing process. Previous spray frequency formulas are derived empirically from field observations considering only the ship’s forward speed and oceanographic conditions. The significance of various degrees of ship motions on the spray frequency is ignored. However in reality, the interrelationships of heave and pitch motions under wave actions together with surge motion determine the number of spray events that a ship may experience in a given period of time. This paper introduces a theoretical model for estimating the frequency of sea spray considering ship motions. Ship motions can be easily estimated by strip/panel methods. However, in this work, the aim was to develop a simple framework for a quick estimate of spray frequency. The model inputs are, therefore, restricted to ship’s principal particulars, its operating conditions, and the environmental conditions. The wave-induced motions are estimated by semi empirical analytical expressions. A novel spray threshold is developed to keep the deck wetness frequency separated from the spray frequency. The proposed spray frequency formula is validated against available full-scale field measurements from a Russian fishing vessel, MFV Narva, and reasonable agreement is found. Limitations of previous empirical formulas are also discussed.

Effects of earthworm communities on water infiltration in wet soils with energy crops

2020 ◽  
Author(s):  
Lena Wöhl ◽  
Stefan Schrader
Keyword(s):  
Ecosystem Services ◽  
Ecological Impact ◽  
Live Weight ◽  
Allyl Isothiocyanate ◽  
Infiltration Rate ◽  
Energy Crops ◽  
Water Infiltration ◽  
Energy Crop ◽  
Negative Effects ◽  
Infiltration Rates

<p>Maize (<em>Zea mays</em>) is the most commonly cultivated energy crop throughout Europe. However, its cultivation has severe negative effects such as loss of biodiversity and its delivery of ecosystem services, soil compaction and enhanced greenhouse gas emissions. These negative effects tend to be even more pronounced in wet soils such as pseudogleys. As an alternative to annual maize, the perennial cup plant (<em>Silphium perfoliatum</em>) is known to produce a similar yield, especially under waterlogging conditions, while management impacts of its cultivation are assumed to be less harmful to soil biota. Therefore, the aim of the present study was to quantify the provision of ecosystem services (here: control of the soil water balance) delivered by earthworm communities in wet soils under cultivation of cup plant compared with maize and to assess the ecological impact of both energy crops.</p><p>Fieldwork was conducted cup plant and maize fields (n = 4) in South Western Germany in spring and autumn 2019. The overall soil type was pseudo gleyic luvisol. All fields are managed for commercial purposes by farmers in the area. Sampling included earthworm extraction with allyl isothiocyanate (AITC) while the infiltration rate was measured simultaneously. Afterwards, hand sorting completed the earthworm sampling. Earthworm species, their abundance and biomass (live weight) were determined.</p><p>On average, earthworm abundance and biomass were higher in cup plant fields than in maize fields. In addition, variations in earthworm communities were found. While endogeic earthworms, especially of the genus <em>Aporrectodea</em>, were present in all fields, anecic earthworms were more abundant in cup plant fields. Higher infiltration rates were measured in maize fields. Hints to a correlation between the infiltration rates and the functional earthworm groups were found.</p><p>Our results suggest that cup plant fields host overall more diverse earthworm communities. These communities are able to produce a wider range of ecosystem services, even though the link between the infiltration and the crops studied in this stud is not yet validated.</p>

Computational Evaluation of Low NOx Operating Conditions in Arch-Fired Boilers

1999 ◽  
Vol 121 (4) ◽  
pp. 735-740 ◽  
Author(s):  
N. Fueyo ◽  
V. Gambo´n ◽  
C. Dopazo ◽  
J. F. Gonza´lez
Keyword(s):  
Computational Model ◽  
Field Measurements ◽  
Operating Conditions ◽  
Formation Mechanisms ◽  
Local Concentration ◽  
Nox Formation ◽  
Operating Modes ◽  
Computational Evaluation ◽  
Chemical Conditions ◽  
Coal Boiler

In the present paper, a computational model is used to simulate the aero-dynamic, thermal, and chemical conditions inside an arch-fired coal boiler. The model is based on the Eulerian-Eulerian concept, in which Eulerian conservation equations are solved both for the gas and the particulate phases. A NOx formation and destruction submodel is used to calculate the local concentration of NO. The model is used to simulate a range of operating conditions in an actual, 350 MW, arch-fired boiler, with the aim of reducing, using primary measures, the emissions of NOx. The model results shed some light on the relevant NOx-formation mechanisms under the several operating conditions. Furthermore, they correlate well quantitatively with the available field measurements at the plant, and reproduce satisfactorily the tendencies observed under the different operating modes.

Mapping Optimum Nitrogen Crop Uptake

2017 ◽  
Vol 8 (2) ◽  
pp. 322-327
Author(s):  
J. Villodre ◽  
I. Campos ◽  
H. Lopez-Corcoles ◽  
J. Gonzalez-Piqueras ◽  
L. González ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Nitrogen Concentration ◽  
Field Measurements ◽  
Growing Season ◽  
Crop Growth Model ◽  
Crop Uptake ◽  
Use Efficiency ◽  
Critical Nitrogen Concentration ◽  
Nitrogen Treatments ◽  
Crop Biomass

This work proposes a methodology that uses remote sensing (RS) images to obtain optimum nitrogen crop uptake (Nuptake) maps, for the all pixels in the image included in the field during the entire growing season. The Nuptake was determined from relationship between critical nitrogen concentration (Nc) and biomass where biomass was estimated by a crop growth model based on the water use efficiency. The paper proposes the use of this methodology in commercial wheat farm. The results are discussed with respect to field measurements of crop biomass and N concentration on different dates and in zones with different nitrogen treatments from 8 commercial wheat farms in Albacete, Spain during 2015 and 2016.

scholarly journals Energy production systems of phototroph microorganisms (classification of photobioreactors)

2010 ◽  
pp. 35-39
Author(s):  
Csongor Gábor Kiss
Keyword(s):  
Industrial Production ◽  
Alternative Energy ◽  
Production Systems ◽  
Type Systems ◽  
Energy Crops ◽  
Energy Crop ◽  
Bioenergy Feedstock ◽  
Alternative Energy Sources ◽  
Closed Type ◽  
Pond Type

In the field of alternative energy sources there is an argue in the comparison of its effects on the benefits and disadvantages to the economics and the environment. New studies are born which are in contradiction with each other. The demand for bioenergy feedstock is growing rapidly however there are the environmental problems caused by the extending energy crop plantations. There is such a significant need for land to grow traditional energy crops on (rape, soy, palm-oil, sugarcane, etc.) that the food purpose agricultural capacity could be in danger. Probably the extensivelygrowing energy crops play a role in the very high prices of food. In some countries like China for example laws prohibit the use of food based crops such as corn for energie production. In the case of corn based ethanol production the cost only for the feedstock itself is over 60% of the whole preparation costs which significantly effects the entire economy of the energy productions process.The microalgaes however have a huge biotechnological potential and their production is notably cheaper then the traditionaly grown food crops growing expenses. They play a significant role as feedstocks in todays industrial production in such fields as comestible production, cosmetics, pharmaceutics and biotechnology especially in biofule production. In the field of economy the major aspects here are also the technological designsand the construction. For the future industrial production the closed type systems seem to have more advantages compared to the open, pond-type systems. For high value material production the more innovative and more easily developed closed photobioreactors are the profitable regardless the vast techological designs used in the construction. 

Improved Temperature Mapping of EHL Contacts

2008 ◽  
Author(s):  
T. Reddyhoff ◽  
H. A. Spikes ◽  
A. V. Olver
Keyword(s):  
Effective Means ◽  
Field Measurements ◽  
Operating Conditions ◽  
Additional Advantage ◽  
Ir Camera ◽  
Full Field ◽  
Traction Fluid ◽  
Increased Sensitivity ◽  
Cooling Effects ◽  
Traction Fluids

An effective means of studying lubricant film rheology within EHL contacts is by detailed mapping of the temperature of the fluid and the bounding surfaces within the lubricated contact area. This provides a way of directly measuring the rheology of lubricant films under true EHL conditions. Furthermore, temperature measurement itself provides a very effective means of testing and validating computer simulations. In the current work, the experimental approach initially developed by Sanborn and Winer [1] and then by Spikes and co-workers [2], has been advanced to include a high specification infrared (IR) camera and microscope. This is a similar approach to that taken by Yagi and Kyogoku [3]. As well as the instantaneous capture of full field measurements, this has the advantage of increased sensitivity and higher spatial resolution than previous systems used. The increased sensitivity enables a much larger range of testable operating conditions; namely lower loads, speeds and reduced sliding. In addition, the range of test lubricants can be extended beyond high shearing traction fluids. One additional advantage of instantaneous full field measurements is that the weak infrared optical interference caused by the film can be observed and can used to exactly locate the centre of the contact in the resulting temperature maps. These new possibilities have been used to investigate and compare the rheological properties and compression cooling effects exhibited by a PAO, a group II mineral oil, and a traction fluid.

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