Energy Production Rate Research Articles

A Parameterisation ofγ-ray production cross-sections for pp interactions in a broad energy range

Using different Monte Carlo codes such as Geant 4.10, Pythia 8.18, SIBYLL and QGSJET, as well as compiling published data on pp interactions close to the kinematic threshold, we parametrize the energy spectra and production rates of gamma-rays by simple but quite accurate (≤ 20%) analytical expressions in a broad range from the kinematic threshold to PeV energies.

Identification and analysis of nutritional components of Enset (Ensete ventricosum) landraces suitable for corm production in Southern Ethiopia.

Enset (Ensete ventricosum) produces a nutritious human food from its vigorous pseudostem, corm and the stalk of inflorescence. Among the many different food made from Enset is 'Amicho ', which is a stripped corm of a younger plant of Enset, boiled and consumed in a way similar to Irish potato, sweet potato and cassava. Participatory Rural Appraisal (PRA) and formal survey were conducted in two weredas, one from each of two densely populated Enset growing zones (namely Sidama and Hadiya zones in the Southern Nations, Nationalities and Peoples Region of Ethiopia) to collect Enset landraces suitable for edible corm production and assess their nutrient contents. Eleven Enset land races suitable for edible corm production were identified and planted at Hawassa University experimental field for further investigation. The result of nutritional analysis showed a marked significant variability in the nutritional composition of the corms; this made the selection of nutritionally-rich Enset landraces possible. Large differences in protein content (0.90 to 2.39%), crude fibre (0.83 to 1.1%), carbohydrates (27.3 to 39.4 ), Fe (1.1 to 4.3 mg/100 gm), Zn (6.2 to 15.6 mg/100 gm) and Beta carotene (1 .5 to 22.2 μ g/100 gm) were recorded. 'Agade', 'Askala', and 'Gossalo' landraces had the highest protein, carbohydrates and Beta-carotene contents, respectively. 'Made' contained the highest crude fibre, Fe and Zn contents. The average protein content (1.4%) of corms of the Enset landraces was comparable to the average protein content of most root and tuber crops; whereas, the average Fe and Zn contents of corms of the Enset landraces were higher than the values reported for most root and tuber crops. The average energy and dry matter production rates of corms of the Enset landraces were about 124% and 169% higher, respectively than the average values for root and tuber crops. While Enset is conventionally perceived as having relatively low nutritional content when compared with other root and tuber crops, the present study provides evidence that, contrary to popular perception, there are excelling nutritional values of corms of the Enset landraces for humans. Keywords: Ensete ventricosum , landraces, corm, nutritional quality

Parametrization of gamma-ray production cross sections forppinteractions in a broad proton energy range from the kinematic threshold to PeV energies

Using publicly available Monte Carlo codes as well as compilation of published data on p--p interactions for proton kinetic energy below 2 GeV, we parametrize the energy spectra and production rates of $\gamma$-rays by simple but quite accurate ($\leq 20 \%$) analytical expressions in a broad range from the kinematic threshold to PeV energies.

Wave energy potential assessment in the Caribbean Low Level Jet using wave hindcast information

We investigate the wave energy potential in the Caribbean Sea using a 30-year wave hindcast. Wave energy in enclosed sea basins, such as the Gulf of Mexico and the Caribbean Sea, is commonly associated with lower energy production rates. However, an easterly zonal wind reaching 13m/s, known as the Caribbean Low-Level Jet (CCLJ), is shown to control the wave climatology in the Caribbean Sea. The wave hindcast information is validated with altimetry (Globwave) and buoy (DIMAR) data from the Colombian Caribbean Sea. The wave hindcast performance is very satisfactory at two buoy locations (Barranquilla and Providencia) and with respect to altimetry information, but presents an underprediction of extreme events at Puerto Bolivar. Therefore, an assessment of wave energy in the study area, based on wave hindcast information, is conducted to investigate the wave energy potential in such enclosed area. Numerical results suggest that the CLLJ region is suitable for wave energy extraction (8–14kW/m) and presents important spatial gradients that need to be considered for the installation of wave energy devices. Furthermore, it is found that locally generated (sea) wave energy can be suitable for energy production and hence future technology development should be devoted to its harvesting.

Direct numerical simulation of turbulent wake behind a surface-mounted square cylinder

In this research, direct numerical simulation has been performed to study the turbulent wake behind a wall-mounted square cylinder with aspect ratio 4 and Reynolds number 12000 (based on the free-stream velocity and obstacle side length) in a developing boundary layer. Owing to the relatively high Reynolds number and high aspect ratio of the cylinder tested, the wake is wide spread behind the cylinder and exhibits complex and energetic vortex motions. The lateral and tip vortex shedding patterns at different frequencies, coherent structures downstream of the obstacle, the production rate and distribution of turbulent kinetic energy, and the instantaneous pressure distribution in the wake region have been thoroughly investigated. In order to validate the numerical results, the first- and second-order flow statistics obtained from the simulations have been carefully compared against available wind-tunnel measurement data.

Research of iron ore grinding in a vertical-roller-mill

The total energy consumption for ore comminution will further increase within the next decades. One contribution to minimise the increase is to use more efficient comminution equipment. Vertical-roller-mills (VRM) are an energy-efficient alternative to conventional grinding technology. One reason is the dry in-bed grinding principle. Results of extensive test works with two types of magnetite iron ores in a Loesche VRM are presented here. Within these test works, mill parameters like grinding pressure, separator speed and dam ring height were varied, following a factorial design of the experiments. The effects of the grinding parameters on the liberation of valuable minerals are characterised using mineral liberation analysis (MLA). It is shown how the different mill parameters influence important performance values like energy consumption, production rate and mineral liberation. Via multiple regression analysis, an optimal parameter range can be modelled for both ore types. The parameter predictions have been successfully verified in practical test works.

Caloric restriction impedes age-related decline of mitochondrial function and neuronal activity.

Caloric restriction (CR) prolongs lifespan and retards many detrimental effects of aging, but its effect on brain mitochondrial function and neuronal activity--especially in healthy aging--remains unexplored. Here we measured rates of neuronal glucose oxidation and glutamate-glutamine neurotransmitter cycling in young control, old control (i.e., healthy aging), and old CR rats using in vivo nuclear magnetic resonance spectroscopy. We found that, compared with the young control, neuronal energy production and neurotransmission rates were significantly reduced in healthy aging, but were preserved in old CR rats. The results suggest that CR mitigated the age-related deceleration of brain physiology.

Black hole feedback in a multiphase interstellar medium

Ultrafast outflows (UFOs) from supermassive black holes (SMBHs) are thought to regulate the growth of SMBHs and host galaxies, resulting in a number of observational correlations. We present high-resolution numerical simulations of the impact of a thermalized UFO on the ambient gas in the inner part of the host galaxy. Our results depend strongly on whether the gas is homogeneous or clumpy. In the former case all of the ambient gas is driven outward rapidly as expected based on commonly used energy budget arguments, while in the latter the flows of mass and energy decouple. Carrying most of the energy, the shocked UFO escapes from the bulge via paths of least resistance, taking with it only the low-density phase of the host. Most of the mass is however in the high-density phase, and is affected by the UFO much less strongly, and may even continue to flow inwards. We suggest that the UFO energy leakage through the pores in the multiphase interstellar medium (ISM) may explain why observed SMBHs are so massive despite their overwhelmingly large energy production rates. The multiphase ISM effects reported here are probably under-resolved in cosmological simulations but may be included in prescriptions for active galactic nuclei feedback in future simulations and in semi-analytical models.

Effects of climate change on wind energy production in Iran

This study explores the effect of future climate change on wind energy conversion in Iran, based on data from existing wind farms. In an effort to estimate and understand the effects of climate change on the potential of wind energy production, the southwestern and western regions of Iran have been studied. In this region, the three provinces of Ilam, Kermanshah and Khuzestan have been studied in detail, along with their 12 weather stations. To simulate future temperatures, the HADCAM3 general circulation model and A1b and A2 scenarios were used. The method of artificial neural network (ANN) was deployed to predict the measures of relative humidity. To compare the rate of energy production for the two periods of present and future conditions, two time scales, 1987–2009 and 2046–2065, were taken into account. The main results demonstrate that there is an agreement between the two future climate scenarios, A1b and A2. In both simulations, Dehloran City showed the highest moist air density and, consequently, the highest wind energy production. In the other cities, a decrease in wind energy production was observed. Finally, if the mean working life of a wind farm is assumed to be between 20 and 30 years, the more promising regions in which to implement and/or renovate wind farms, in Iran, can be determined, according to the expected future wind energy production. The research further indicates an increase in temperature in most of the stations in the months studied and a decrease in the capacity of wind energy production in most stations. Therefore, a lack of proper management of supply and a demand of energy for cooling and ventilation of settlements in the studied regions can lead to challenges in providing the society with healthy climatic conditions in that area. Thus, a proper alternative, such as solar energy, to supply the region with clean energy is proposed.

Galaxy And Mass Assembly (GAMA): ugrizYJHK Sérsic luminosity functions and the cosmic spectral energy distribution by Hubble type

We report the morphological classification of 3727 galaxies from the Galaxy and Mass Assembly survey with M_r < -17.4 mag and in the redshift range 0.025 < z < 0.06 (2.1 x 10^5 Mpc^3 ) into E, S0-Sa, SB0-SBa, Sab-Scd, SBab-SBcd, Sd-Irr and little blue spheroid classes. Approximately 70% of galaxies in our sample are disk dominated systems, with the remaining ~30% spheroid dominated. We establish the robustness of our classifications, and use them to derive morphological-type luminosity functions and luminosity densities in the ugrizYJHK passbands, improving on prior studies that split by global colour or light profile shape alone. We find that the total galaxy luminosity function is best described by a double-Schechter function while the constituent morphological-type luminosity functions are well described by a single-Schechter function. These data are also used to derive the star-formation rate densities for each Hubble class, and the attenuated and unattenuated (corrected for dust) cosmic spectral energy distributions, i.e., the instantaneous energy production budget. While the observed optical/near-IR energy budget is dominated 58:42 by galaxies with a significant spheroidal component, the actual energy production rate is reversed, i.e., the combined disk dominated populations generate ~1.3x as much energy as the spheroid dominated populations. On the grandest scale, this implies that chemical evolution in the local Universe is currently confined to mid-type spiral classes like our Milky Way.

Estimates of reynolds stress and TKE production in the seasonally stratified East China Sea

During the two cruises in March and July of 2011, the tidal cycling of turbulent properties and the T/S profiles at the same location in seasonally stratified East China Sea (ECS) were measured synchronously by a bottom-mounted fast sampling ADCP (acoustic Doppler current profiler) and a RBR CTD (RBR-620) profiler. While focusing on the tide-induced and stratification’s impact on mixing, the Reynolds stress and the turbulent kinetic energy (TKE) production rate were calculated using the ‘variance method’. In spring, the features of mixing mainly induced by tides were clear when the water column was well-mixed. Velocity shear and turbulent parameters intensified towards the seabed due to the bottom friction. The components of the velocity shear and the Reynolds stress displayed a dominant semi-diurnal variation related to velocity changes caused by the flood and ebb of M2 tide. Stratification occurred in summer, and the water column showed a strongly stratified pycnocline with a characteristic squared buoyancy frequency of N2 ∼ (1–6) × 10−3 s−2. The components of the velocity shear and the Reynolds stress penetrated upwards very fast from the bottom boundary layer to the whole water column in spring, while in summer they only penetrated to the bottom of the pycnocline with a relatively slow propagation speed. In summer, the TKE production within the pycnocline was comparable with and sometimes larger than that in the well-mixed bottom layer under the pycnocline. Considering the associated high velocity shear, it is speculated that the mixing in the pycnocline is a result of the local velocity shear.

Experimental study of spectral energy fluxes in turbulence generated by a fractal, tree-like object

We report on an experimental study of the kinetic energy fluxes between scales in the turbulent near-wake flow downstream of a fractal, tree-like object. Experiments are performed in a liquid channel and data are acquired using planar Particle Image Velocimetry (PIV). The data are analyzed based on the filtering framework of relevance to Large Eddy Simulations. The flow and energy fluxes differ from the case of a canonical flow such as the cylinder wake, where typically kinetic energy is injected into turbulence by an object characterized by a single, well-defined, length-scale. For a fractal tree-like object, we find that the measured energy flux is strongly dependent on scale. In the present flow, scale-dependent injection of kinetic energy into the cascade arises from production as well as spatial transport terms. The injection rate spectrum is evaluated directly from the data by quantifying the rate of change of spectral energy flux as a function of wavenumber. The net injection rate spectrum is observed to scale approximately as ∼k−7/3, in accordance with heuristic and dimensional arguments previously used for the kinetic energy production rate spectrum in shear flows. In order to scale the results, we consider an equivalent mixing length-scale that can be obtained from the tree geometry by adding over the relevant scales of successive branch clusters. In prior work, this equivalent length scale has been found to collapse the eddy-viscosity well. Here we find that this scale also collapses the energy flux and the net injection rate spectrum successfully.

Optimization of cutting parameters for energy saving

Correct selection of cutting parameters is one of effective approaches to achieve optimum machining process, including reducing energy consumption. For the close relationship between cutting parameters and energy consumption in machining process, energy consumed is modeled and to be reduced based on analyzing the energy consumption in this paper. According to the different requirements in roughing process and finishing process, corresponding multi-objective optimization functions are formulated considering energy consumption. Taking the optimization of milling operations on aluminum alloy as an example, experiments are carried out to analyze the energy consumption and production rate with sets of optimized/un-optimized cutting parameters for different objectives. The experimental results show that the objectives of low consumed energy and high production rate can be simultaneously achieved by optimization of cutting parameters.

Reverse osmosis (RO) and pressure retarded osmosis (PRO) hybrid processes: Model-based scenario study

We conducted a scenario study on a promising RO–PRO hybrid system to alleviate water and energy demands. We utilized a previously validated reverse osmosis (RO) process model and modified a model of a pressure-retarded osmosis (PRO) process to properly consider the spatial distribution of concentration and velocity based on a mass balance principle. Using the models, we compared four different RO–PRO hybrid configurations based on the water and energy return rate (WERR). Subsequently, the comparison of the water production rate and energy production rate confirmed the results that RO plays a dominant role to determine the WERR value. Hybrid systems that use seawater as a feed water for RO are more energy price sensitive. That is, a decrease in the RO plant size considerably diminishes the WERR values; however, the PRO plant size plays a minor role to determine the WERR value. Research and available literature on RO–PRO hybrid processes are in a relatively early stage; this study is a preliminary step to evaluate further advances in hybrid systems that can eventually alleviate water and energy demands.

Changes in leaf proteome profile of Arabidopsis thaliana in response to salicylic acid

Salicylic acid (SA) has been implicated in determining the outcome of interactions between many plants and their pathogens. Global changes in response to this phytohormone have been observed at the transcript level, but little is known of how it induces changes in protein abundance. To this end we have investigated the effect of 1 mM SA on soluble proteins of Arabidopsis thaliana leaves by proteomic analysis. An initial study at transcript level has been performed on temporal landscape, which revealed that induction of most of the SA-responsive genes occurs within 3 to 6 h post treatment (HPT) and the expression peaked within 24 HPT. Two-dimensional gel electrophoresis (2-DE) coupled with MALDI-TOF MS/MS analysis has been used to identify differentially expressed proteins and 63 spots have been identified successfully. This comparative proteomic profiling of SA treated leaves versus control leaves demonstrated the changes of many defence related proteins like pathogenesis related protein 10a (PR10a), diseaseresistance- like protein, putative late blight-resistance protein, WRKY4, MYB4, etc. along with gross increase in the rate of energy production, while other general metabolism rate is slightly toned down, presumably signifying a transition from 'normal mode' to 'defence mode'.

Sequential shift of energy production pathways at the fetal stage and during lifetime

As eukaryotes, human beings spend their lifetime using two different pathways for energy production: the anaerobic glycolysis pathway and aerobic mitochondria pathway. Energy produced using the glycolysis pathway is utilized for cell division and prompt force of white fiber muscles whereas that produced by the mitochondria pathway is utilized for suppression of cell division and continuous force of red fiber muscles. Herein, it is proposed that there exists a sequential shift of energy production pathways at the fetal stage and during the lifetime. If we introduce this concept in human biology, then it is may be easy to understand the energy requirement characteristics of fetuses, children, adults and aged persons. For example, during childhood the glycolysis pathway is more predominant than the mitochondria pathway in energy production. Reflecting this fact, children grow and extend their height by division of generalized cells of the body. To achieve this, they have to eat meals many times a day (more than three times a day) due to a less efficient energy production rate in the glycolysis pathway. Similarly, the characteristics of adults and aged persons can be well described using this concept.

Variability of turbulent quantities in the tidal bottom boundary layer: Case study in the eastern English Channel

Tidal current structure and turbulent quantities within a tidal bottom boundary layer (BBL) have been examined using an upward-looking acoustic Doppler current profiler (ADCP). The instrument was deployed on the seafloor, off the north-eastern French coast in the eastern English Channel over 12 tidal cycles and covered the period of the transition from mean spring to neap tide. Forcing regimes varied from calm to moderate storm conditions during the deployment. For the study of turbulent quantities in the BBL, we have chosen a calm period, when an effect of surface waves on the velocity structure was negligible. Stresses were found to vary regularly with the predominantly semidiurnal tidal flow, with the along-shore stress being generally greater during the flood flow (∼3.0Pa) than during the ebb flow (∼−1.5Pa). The turbulent kinetic energy (TKE) production rate, P, TKE density, Q, and its dissipation rate, ε, followed a nearly regular cycle with close to quarter-diurnal period. Near the seabed, peak values of P, Q and ε were found to be 0.5Wm−3, 0.5m2s−2 and, 0.04Wm−3, respectively, during the flood while, during the ebb, these quantities reached lesser values: 0.1Wm−3, 0.1m2s−2 and 0.03Wm−3, respectively. Near the bottom, eddy viscosity, Az, peak ranged from about 0.1m2s−1 during the flood to 0.03m2s−1 during the ebb flow. Away from the bottom, Az increased to reach a maximum near the mid-depth. Time–depth variation of the P/ε ratio indicated that the turbulence in the BBL, most of the time, was at a non-equilibrium state (P/ε≠1). The largest deviation from the equilibrium occurred during the flood, when P/ε exceeded about one decade near the bottom. During the ebb, P/ε was close to the equilibrium state, slightly decreasing with height above the bottom. Results are found to be in a good agreement with those of the other researches working on direct measurements of turbulence in tidal flows.

Biohydrogen from molasses with ethanol-type fermentation: Effect of hydraulic retention time

Though ethanol-type fermentation has many advantages for improving hydrogen production rate (HPR) in continuously mode hydrogen producing system, information on this fermentation is very deficient. The effect of hydraulic retention time (HRT) on biohydrogen production and operational stability of ethanol-type fermentation was investigated in a continuous stirred tank reactor (CSTR) using molasses as substrate. Five HRTs were examined, ranging from 4 to 10 h. At HRT 5 h, the highest HPR of 12.27 mmol L−1 h−1 was obtained from ethanol-type fermentation in the pH range of 4.3–4.4. During the whole operation process, ethanol, butyrate and acetate were the predominant metabolites. A total COD concentration of ethanol and acetate accounted for above 73.3% of total soluble microbial products. Linear regression showed that HPR and ethanol production rate were proportionately correlated at all HRTs which could be expressed as y = 0.9821x − 3.5151 (r2 = 0.9498). It is meaningful that the proposed recovery of both hydrogen and ethanol from fermentation process can improve energy production rate and economic profit. Results demonstrated that the best energy production rate was 15.50 kJ L−1 h−1, occurred at HRT = 5 h.

Vertical Wind Speed Extrapolation Using the k—ε Turbulence Model

Vertical wind speed extrapolation is an important component of wind resource assessment where measured wind data at a reference height is extrapolated to hub height using the logarithmic or power law. Both models depend on roughness length but disregard information pertinent to topography. The log law results from the balance between turbulent kinetic energy (TKE) production and dissipation rate for fully developed flow over a horizontally homogeneous surface and is not generally valid. In search of a better extrapolation methodology, the k – ε turbulence model is used to simulate measurements of boundary layer flows over hills accurately. By vertically integrating terms of the modeled TKE equation, a generalization of the log law was developed. The improved model includes a radius of curvature term and height for hills. It outperforms the log law for the cases tested.

A Comparative Field-Scale Simulation Study on Feasibility of SAGD and ES-SAGD Processes in Naturally Fractured Bitumen Reservoirs

Thermal processes are widely applied in heavy oil and bitumen reservoirs. Steam-Assisted Gravity Drainage (SAGD) and Expanding Solvent-SAGD (ES-SAGD) are the two most promising techniques for production of heavy oil and bitumen reservoirs. The feasibility and efficiency of the aforementioned processes have been studied extensively for sandstone reservoirs. As there are some naturally fractured heavy oil resources in the world similar thorough studies are necessary to find out the applicability of these processes in these types of reservoirs. In this work several numerical simulations have been performed to investigate the feasibility of these methods in naturally fractured reservoirs (NFR). Dual permeability option was applied in this study. This work tries to cover the effect of several parameters such as reservoir thickness, fracture permeability, matrix permeability, fracture spacing, steam quality and oil viscosity on SAGD and ES-SAGD processes. Results have elucidated that basically both methods are efficient and economically applicable in naturally fractured reservoirs. Recovery factor and cumulative steam-oil ratio (CSOR) were economical parameters to evaluate the performance of processes. However, in some cases net amount of injected energy and oil production rate were considered for evaluation too. Generally ES-SAGD had better performance based on the recovery factor, CSOR, oil production rate and net amount of injected energy. Effect of solvent type and concentration were studied for ES-SAGD process only. For this purpose, pentane, hexane and heptane were selected. Pentane displayed better performance in earlier periods of production; however the heavier solvents showed better recovery performance at later times.