Finite Source Research Articles

Effects of Different Soilless Growing Media on the Growth and Development of Tobacco Seedlings

To prevent reliance on a single finite source of the medium in raising tobacco nurseries, there arose a need to evaluate alternative media based on materials already available on farms. An experiment was set to evaluate the effects of different soilless growing media on the growth and biomass of flue-cured leaf tobacco seedlings. The design used was a randomized complete block design with three replications. The treatments were 100% pine bark (control), 50% cattle manure + 50% sand, 100% coal rubble, 100% compost manure, 50% pine bark + 50% sand, 100% cattle manure, 75% coal rubble + 25% sand, 75% cattle manure + 25% sand, 50% compost manure + 50% sand, and 75% compost manure + 25% sand. The results showed that increased seed emergence and survival percent were observed in the following media; 50% pine bark + 50% sand, 75% coal rubble + 25% sand, 75% compost manure + 25% sand, 100% coal rubble, 100% compost manure, and 50% compost manure + 50% sand, these treatments were not statistically different from 100% pine bark (control). The stem length and diameter of tobacco seedlings were superior in the medium with 100% compost manure when compared to all other treatments including pine bark. Increased transplantable percent of tobacco seedlings were in 50% pine bark + 50% sand and 100% compost manure, significantly higher than 100% pine bark (control). Most treatments that used cattle manure had significantly lower seed emergence percent, survival percentage, and transplantable percent of tobacco seedlings. Therefore, tobacco growers are recommended to use the growing medium with compost manure and should avoid using cattle manure when raising tobacco seedlings in seed beds.

Using Probabilistic Models for Data Compression

Our research objective is to improve the Huffman coding efficiency by adjusting the data using a Poisson distribution, which avoids the undefined entropies too. The scientific value added by our paper consists in the fact of minimizing the average length of the code words, which is greater in the absence of applying the Poisson distribution. Huffman Coding is an error-free compression method, designed to remove the coding redundancy, by yielding the smallest number of code symbols per source symbol, which in practice can be represented by the intensity of an image or the output of a mapping operation. We shall use the images from the PASCAL Visual Object Classes (VOC) to evaluate our methods. In our work we use 10,102 randomly chosen images, such that half of them are for training, while the other half is for testing. The VOC data sets display significant variability regarding object size, orientation, pose, illumination, position and occlusion. The data sets are composed by 20 object classes, respectively: aeroplane, bicycle, bird, boat, bottle, bus, car, motorbike, train, sofa, table, chair, tv/monitor, potted plant, person, cat, cow, dog, horse and sheep. The descriptors of different objects can be compared to give a measurement of their similarity. Image similarity is an important concept in many applications. This paper is focused on the measure of similarity in the computer science domain, more specifically information retrieval and data mining. Our approach uses 64 descriptors for each image belonging to the training and test set, therefore the number of symbols is 64. The data of our information source are different from a finite memory source (Markov), where its output depends on a finite number of previous outputs. When dealing with large volumes of data, an effective approach to increase the Information Retrieval speed is based on using Neural Networks as an artificial intelligent technique.

INVESTIGATION OF N-POLICY MARKOVIAN QUEUEING SYSTEM WITH DESPONDENT ARRIVALS, RETAINMENT OF RENEGED CUSTOMERS AND CONTROLLABLE ARRIVAL RATES

Afinite capacity, finite source, Markovian queueing model with despondent arrivals, retainment of reneged customers and controllable arrival rates is considered. Using this model, a steady-state solution and system characteristics can be obtained. The measures of effectiveness of the queueing model are also derived. Numerical results are given for better understanding and relevant conclusion is presented.

Rotational flux influenced cusp entrainment in a viscous pool

Evolution of entrained gaseous cusp in a viscous liquid pool caused by a fully immersed horizontal revolving circular drum is elucidated thoroughly. Finite volume-based open source Gerris is employed to carry out the numerical simulations. Length θs* and width (H*) of the cusp are characterized thoroughly by varying the strength of rotational flux (measured by the capillary number, Ca) and depth of immersion (submersion height to roller diameter ratio, h/D) of the spinning roller. Locus and travel rate of cusp tip are also elaborated from origination to attainment of steady state with the progress of time for different combinations of Ca and h/D. We have also reported the bubble ejection mechanism from the advancing end of the cusp after achieving macroscopic steady length. Bubbling frequency and volume accumulation of detached bubbles show strong dependency on Ca or h/D. Entrainment patterns are also observed by investigating the effect of gravitational pull (measured by employing the Archimedes number, Ar) and viscous drag (specified by using the Morton number, Mo). Correlations are developed to estimate the cusp width (H*) at different angular locations and steady length of gaseous cusp θs*, which show satisfactory agreement within ±6%. Finally, an analytical model is proposed to determine the cusp width by using the relevant influencing forces acting on the cusp. A satisfactory agreement is obtained between the analytical solutions and computational results.

A global model for fast calculation of the thermal response factor of large-scale boreholes heat exchangers combining the FLS model, the 2D heat equation and a three-points method

In order to progress towards more energy efficient buildings, vertical ground coupled heat pumps are a promising solution. Optimisation of both the design and operation of boreholes heat exchangers is a key factor to reduce energy consumption of such systems. This requires a fast evaluation of the thermal response factor of the ground heat exchanger, particularly if it contains numerous boreholes and operates for multiple years. To overcome this challenge, this article reports a new global model combining the finite line source (FLS) model, the two-dimensional (2D) heat conduction equation, and a newly developed three-points method. The borehole field is sorted in increasing distance categories, each being simulated with varying timesteps. The 2D heat conduction equation is used to determine: 1) when the detailed calculation needs to be performed; and 2) the growth of the timestep. A three-points method avoiding double integration of the temperature profiles is proposed to evaluate the borehole wall temperature. The global model calculation time and accuracy were evaluated. The thermal response factor calculation for a square field of 26×26 boreholes for one simulated year took 4s, showing a calculation time reduction factor of around 1,000,000, and relative errors smaller than 2 % compared to the original FLS model with superposition principle. For 20 simulated years, the proposed model took only 1min. It is appropriate for various boreholes configurations. Its features such as accuracy, speed and load-independency are essential for its integration into building energy simulation tools.

Asymptotic waiting time analysis of finite source $M/GI/1$ retrial queueing systems with conflicts and unreliable server

Asymptotic waiting time analysis of finite source $M/GI/1$ retrial queueing systems with conflicts and unreliable server

Image systems for regularised Stokeslets at walls and free surfaces

Flow around, and hydrodynamic forces on, moving objects can be determined for low Reynolds numbers by superposing elemental Stokeslets to enforce velocity boundary conditions. The method of regularised Stokeslets provides a computationally-practical approach, replacing a sum over singular point elements by one over finite distributed sources. Flow disturbances extend a considerable distance in low-Re flow (typically falling off in magnitude as the reciprocal of distance) and the presence and nature of a nearby boundary cause a profound change to forces on moving objects. Representing boundaries by additional Stokeslets requires significantly more computational resources, so it is common to represent single planar boundaries by the method of images.Here we formally state the image systems for regularised Stokeslets in the case of plane no-slip walls and free surfaces in a form that is independent of orientation and in canonical six-term forms (for velocity) and three-term forms (for pressure) that are convenient for computation. We validate our implementation using exact solutions (sphere moving in unbounded flow and parallel or perpendicular to slip or no-slip boundaries) and previous simulations (translating and rotating helical filament). We then present new comparisons with experimental data for velocity profiles and forces on objects translating (towed cube in a confined tank) and rotating (helical micro-robot). Our simulations illustrate competing physical effects near a boundary. For an object moving, or propelling fluid, toward or away from a boundary, whether slip or no-slip, an increase in thrust is required to redirect fluid through 90°; viscous drag on a no-slip boundary increases the resistance coefficient further. For an object moving parallel to a boundary, however, opposing effects with different range come into play: the absence of fluid above the boundary reduces the required overall thrust on the fluid over a wide range of gap sizes, but enhanced viscous drag near a no-slip wall exceeds this at small gap sizes.

THE MARCH 25, 2020 M<sub>W</sub>=7.5 PARAMUSHIR EARTHQUAKE AND ITS IMPACT ON RECENT GEODYNAMICS OF THE ADJACENT SECTION OF THE KURIL-KAMCHATKA SUBDUCTION ZONE

An intraplate tsunamigenic earthquake with МW=7.5 occurred on March 25, 2020 southeast of the Paramushir Island (Kuril Islands) beneath the outer slope of the Kuril-Kamchatka Trench. Since 1900, this earthquake has been the largest event for an 800-km long oceanic slope and a 300-km long segment of the Kuril seismofocal zone located near the epicenter. Sub-horizontal compression stresses generated in the earthquake source region were oriented across the seismofocal zone. A type of motion is represented by reverse faulting along the both nodal planes.The compressive stress state in which there occurred the Paramushir earthquake reflects the present-day geodynamics in the subduction zone near the hypocenter. The paper shows that the earthquake occurrence is due to a strong mechanical contact surface between the Pacific and North American lithospheric plates in the subduction zone. The analysis of coseismic displacement of the nearest Global Navigation Satellite System (GNSS) station served as confirmation of the determination of fault plane solution of the earthquake. A seismogenerating motion occurred along the plane oriented to the southwest and dipping towards the trench. For Finite fault source models, there were calculated the increments of the Coulomb stress in the subduction zone. For the main fault plane, the increment of the Coulomb stress in the interpolate contact area propagates to a depth of ~30 km and reaches 1 bar.Coseismic stress increment in the subduction zone at the northern flank of the Kuril island arc, which has a high seismic potential at the present stage of the tectonic cycle, increases the likelihood of the largest interplate earthquake occurrence therein.

Maximum work output configuration of finite potential source irreversible isothermal chemical engines with bypass mass leakage and mass resistance

A model of a finite potential source irreversible isothermal chemical engine (ICE) cycle with bypass mass leakage and mass resistance is established. Mass transfer processes are assumed to obey linear mass transfer law [g∝Δ(μ)] in linear irreversible thermodynamics. The optimality condition for the maximum work output of the ICE cycle is derived by applying averaged optimal control theory. Effects of total mass of high-chemical-potential reservoir and bypass mass leakage on optimization results are analyzed. The results obtained in this paper are rather general, which include those for various special cases including infinite and finite potential source endoreversible ICE cycles, and infinite potential source irreversible ICE cycles.

Numerical research on the heat transfer model and performance of deep borehole heat exchangers combined with geothermal wells

• A deep borehole heat exchanger combined with the geothermal wells is proposed. • A three-dimensional mathematical model considering the forced seepage is established. • The dimensionless analytical solutions are developed and verified. • The effect of the exploitation quantity of geothermal water on the DBHE is analysed. • The thermal diffusion radius under different exploitation quantities is studied. For the purpose of carbon neutrality, deep borehole heat exchanger (DBHE) is widely utilized in building heating by efficiently developing hydrothermal geothermal resources. In this study, a DBHE combined with the geothermal wells is proposed given that there are abundant hydrothermal geothermal resources in the BoHai Bay basin, China. A three-dimensional unsteady heat and mass transfer model coupled with DBHE and thermal reservoir is developed taking into account the forced seepage. Based on the moving finite line source model, the transient dimensionless analytical solutions are derived by applying Fourier and Laplace transform. The proposed model and solving method are validated against the experimental data determined from a field test and the previous numerical simulations, respectively. The calculation results indicate that the heat transfer power per unit buried depth increases by 39.60 W/m and its decline rate throughout the operating period decreases by 7.17% when the exploitation quantity of geothermal water increases from 0 m 3 /h to 120 m 3 /h. With the increase of exploitation quantity, the thermal diffusion radius ranges from 10.11 m to 20.34 m at the downstream, however, the thermal diffusion radius decreases from 10.11 m to 9.01 m at the upstream. When the exploitation quantity of geothermal water is 0 m 3 /h, 60 m 3 /h and 120 m 3 /h, the average heat transfer power increases by 139.37 kW, 174.20 kW and 200.80 kW respectively with the increase of circular quantity of DBHE from 10 m 3 /h to 60 m 3 /h. When the exploitation quantity of geothermal water increases, the forced seepage (Darcy flow rate) in the thermal reservoir is enhanced, and the influence of the circular quantity of the DBHE on the heat transfer performance is improved. The DBHE combined with the geothermal wells can be utilized in the case of existing geothermal well construction, which will enhance the heat transfer performance of DBHE substantially. The conclusions obtained from this research will be a reference to guide further research and application of the DBHE or DBHE array combined with the geothermal wells under different geological conditions and operation modes.

A novel liquid metal MHD enhanced Closed-Brayton-Cycle power generation system for hypersonic vehicles: Thermodynamic analysis and performance evaluation with finite cold source

Closed-Brayton-cycle (CBC) is a potential thermodynamic cycle for high-power dynamic electricity generation on hypersonic vehicles, but finite cold source onboard limits its power level. This study presents a liquid metal MHD (LMMHD) enhanced CBC power generation system and exhibits its theoretical advantages through thermodynamic analysis. The influence of cold source temperature rise, turbine inlet temperature and LMMHD conversion efficiency on system performance is investigated by a zero-dimensional power optimization model, and the electric power and power generation efficiency between LMMHD enhanced CBC and standalone CBC are compared. Results indicate that LMMHD enhanced CBC can theoretically meet the demand for megawatt-class power generation on hypersonic vehicles, the electric power per unit fuel mass flowrate of which can reach 637.84 kW. High-temperature liquid metal and well-designed LMMHD generator are extremely essential to improve the turbine inlet temperature and LMMHD conversion efficiency. Compared with standalone CBC, the electric power increased percentage of LMMHD enhanced CBC is as high as 92.44 %. This paper provides primary performance evaluation for LMMHD enhanced CBC, the key technical issues of which, including the LMMHD generator structure design, mixing and separation process optimization, will be the focus in our next work.

Stress Drop Estimates for Small to Moderate Earthquakes in Tohoku, Japan Considering Rupture Geometry, Speed, and Directivity

AbstractThis study develops a spectral ratio method to estimate the earthquake stress drop considering the rupture geometry, speed, and directivity. This spectral ratio method is applied to Mw 3.3–5.9 earthquakes in Fukushima and Ibaraki, Japan. A rectangular source model with a square rupture front and uniform slip distribution is used to fit spectral ratios stacked by station and wave type for multiple empirical Green's functions, and estimate the finite source properties. Comparing the rupture areas obtained by the spectral ratio method with the slip inversion results shows that our results from the spectral ratio method are associated with a localized area of large slip rather than the overall rupture area. Hence, the rupture area obtained from this spectral ratio method is inappropriate to calculate the average static stress drop. This study proposes a procedure to estimate the average stress drop for the entire rupture area and one for the localized area with large slip, using a source model with a single asperity and heterogeneous stress drop distribution. As a result, we obtained average static stress drops of 0.42–40.2 MPa with a median of 3.7 MPa. The local stress drop is 5.7 times larger than the average static stress drop. This study suggests that a compact area compared to the overall rupture area mainly controls the shape of a broadband seismic spectrum. Thus, we should consider the source heterogeneity in addition to the rupture geometry, speed, and directivity when estimating the stress drops from seismic spectra.

Mach-Zehnder-based measurement of light emitting diodes temporal coherence

ObjectivesThe main objective of this work is to validate a Mach-Zehnder based interferometric method to measure the temporal coherence length of broadband finite size light sources such as Light Emitting Diodes (LEDs), and give a qualitative value of the temporal coherence length of white LEDs, for which nor their spectral width neither their emission peak wavelength are clearly defined. MotivationLow-coherence light sources such as LEDs have opened many possibilities in applications in which using lasers introduces coherent noise (speckle) that hinders the performance of interferometric measurement techniques. The coherence length is an important characteristic of light sources for scientific applications related to diffraction, holography, tomography, or interferometry. The spatial coherence of a source depends on the distance from the source to the observation plane and its size, while the temporal coherence is related to the emission spectral width and the emission peak wavelength. Therefore, the temporal coherence is a characteristic of each source. Methodology and resultsIn this work, we use a Mach-Zehnder interferometer for the first time to measure the coherence degree and the temporal coherence length of quasi-monochromatic LEDs. We validate the technique by comparing the results to those obtained directly from the spectrum. Then, we use the tested interferometric method to measure the temporal coherence length of a white LED, for which neither the width of the spectrum nor the emission peak wavelength, are clearly defined. In this case, the Wiener-Khinchin theorem is used to validate the interferometric technique. A very interesting property of the method is that the temporal coherence length is obtained from a single measurement, without needing to perform a scanning. This method can be used also for other non-coherent sources such as halogen lamps, pulsed lasers, and so on. The obtained results will improve the characterization of light sources and the applications dealing with physical optics and electromagnetic interference.

Classification and a priori estimates for the singular prescribing Q-curvature equation on 4-manifold

On (M,g) a compact riemannian 4-manifold we consider the prescribed Q-curvature equation defined on M with finite singular sources. We first prove a classification theorem for singular Liouville equations defined on R4 and perform a concentration compactness analysis. Then we derive a quantization result for bubbling solutions and establish a priori estimate under the assumption that certain conformal invariant does not take some quantized values. Furthermore we prove a spherical Harnack inequality around singular sources provided their strength is not an integer. Such an inequality implies that in this case singular sources are isolated simple blow up points.

Optimal Configuration of Finite Source Heat Engine Cycle for Maximum Output Work with Complex Heat Transfer Law

Abstract A finite source heat engine’s optimal configuration is studied. The model includes thermal resistance, heat leakage, a complex heat transfer law, and a heat source with variable temperature. The optimization objective is that the output work is the largest. The influences of factors such as the heat transfer law and heat leakage are analyzed. The results of this paper are universal and inclusive, and provide certain theoretical support for the performance improvement of actual heat engines.

Hydrodynamic signatures in thermal transport in devices based on two-dimensional materials: An ab initio study

We investigate the features arising from hydrodynamic effects in graphene and phosphorene devices with finite heat sources, using ab initio calculations to go beyond Callaway's model and inform a full linearized scattering operator, and solving the phonon Boltzmann transport equation through energy-based deviational Monte Carlo methods. We explain the mechanisms that create those hydrodynamic features, showing that boundary scattering and the relation of sample dimensions to the nonlocal length $\ensuremath{\ell}$ are the determinant factors, regardless of the relative importance of normal versus resistive scattering. From this point of view, the nonlocal length $\ensuremath{\ell}$ reflects the ability of scattering to randomize the heat flux, and we show that approximations made on the scattering operator may have, through the value of $\ensuremath{\ell}$, qualitative consequences on the signatures of hydrodynamic behavior.

The Effect of Renewable and Nonrenewable Energy Use on Sustainable Development in South East Asia

This research focuses on observing the effects of renewable and fossil fuel energy usage on the environment and economic growth in Southeast Asian countries. The study utilized the annual data of southeast Asian countries from 1990 to 2020 This study used gross fixed capital formation, foreign direct investment, renewable energy, population, non-renewable energy, and Labor force on fundaments of economic growth concerning sustainability. Fixed Effect, Radom Effect, and a two-step GMM methodology were used to estimate the link among the variables. The consequences of the study demonstrate that renewable energy intake has a destructive and statistically significant influence the dependent variable: CO2 emission whereas fossil energy has a noteworthy and positive influence on CO2 emissions. Foreign direct investment and population have a significantly positive influence on CO2 emission. While non-renewable and Renewable-energy intake has a momentous optimistic bearing on the economic progress of nominated ASEAN states along through labor force and capital formation. The universal energy needs depend on finite nonrenewable energy sources in the form of natural gas, oil, and coal which are exhaustible and hazardous to the environment. So, the need for hours is that the governments should escalate the use of renewable energy in their energy mix to increase the economy’s growth and environmental sustainability.

A Review of the Emission, Performance, Combustion, and Optimization Parameters in the Production of Biodiesel from Waste Cooking Oil

With the rising consumption of energy comes the challenge of the depletion of fossil fuels. Fossil fuels are non-renewable and finite energy sources with increasing energy demand as a result of the rise in human population and industrialization. This concern has led researchers to seek alternative energy sources that are both economically, technically viable, and environmentally beneficial. Biodiesel is considered an alternative source of energy supply. It is non-toxic, biodegradable, carbon-neutral, and ecologically friendly. However, the high cost of producing biodiesel from feedstocks impedes its commercialization. Hence, WCO used in the production of biodiesel helps to reduce the overall cost of production. The characteristics of the performance, emission, and combustion of the biodiesel produced from the transesterification of WCO are reviewed in this study. The molar ratio of methanol to oil, the concentration of the catalyst, reaction temperature, and time were used to investigate the optimization parameter required in the synthesis of biodiesel from WCO. The number of times the catalyst can be reused while maintaining a good catalytic activity in biodiesel production was also studied. The optimization models and techniques for the prediction of biodiesel yield were also studied.

Performance evaluation for a combined power generation system of closed-Brayton-cycle and thermoelectric generator with finite cold source at room temperature on hypersonic vehicles

Closed-Brayton-cycle (CBC) power generation system is a potential high-power electricity generation scheme for hypersonic vehicles, but finite cold source onboard limits its power level. One of power enhancement approaches is building a combined closed-Brayton-cycle and thermoelectric generator (TEG) power generation system, aimed to extend the available temperature range of cold source. In this study, a combined power generation system based on supercritical carbon dioxide closed-Brayton-cycle in combination with multi-stage thermoelectric generator is advanced on hypersonic vehicles to promote electric power, in which the cold source is hydrocarbon fuel at room temperature. Analysis results indicate that the electric power rise percentage realized by TEG is as high as 68.3%. At the maximum CBC power, the TEG power and according total electric power increase with the highest temperature of TEG coolant, but the increasing rate of electric power becomes lower due to the decrease of conversion efficiency. In addition, although the simple recuperated CBC has advantage on power output with finite cold source, the total power of combined system with recompressing layout is always higher, due to a larger heat absorption capacity of fuel for the thermoelectric conversion of TEG.

Improved Aberth–Ehrlich root-finding algorithm and its further application for binary microlensing

ABSTRACT In gravitational microlensing formalism and for modelling binary light curves, the key step is solving the binary lens equation. Currently, a combination of the Newton’s and Laguerre’s methods which was first introduced by Skowron & Gould (SG) is used while modelling binary light curves. In this paper, we first introduce a fast root-finding algorithm for univariate polynomials based on the Aberth–Ehrlich (AE) method which was first developed in 1967 as an improvement over the Newton’s method. AE algorithm has proven to be much faster than Newton’s, Laguerre’s, and Durand–Kerner methods and unlike other root-finding algorithms, it is able to produce all the roots simultaneously. After improving the basic AE algorithm and discussing its properties, we will optimize it for solving binary lens equations, which are fifth degree polynomials with complex coefficients. Our method is about 1.8–2.0 times faster than the SG algorithm. Since, for calculating magnification factors for point-like or finite source stars, it is necessary to solve the binary lens equation and find the positions of the produced images in the image plane first, this new method will improve the speed and accuracy of binary microlensing modelling.