Liu Model Research Articles

Rainfall partitioning measurement and rainfall interception modelling in a tropical semi-deciduous Atlantic forest remnant

Understanding the interaction between the hydrological cycle and native forests is essential to improve watershed management and support ecological services. The objectives of this study were to analyse and evaluate rainfall interception models applied to an ecosystem from the Brazilian Atlantic Forest Biome (BAFB), classified as “Montane Semi-Deciduous Forest.” The variables Gross Rainfall (P) (rainfall that reaches the canopy), Throughfall (Tf), Stemflow (Sf), and Interception Loss (I) were measured from September 2012 to March 2015. Weather variables were quantified above the canopy by a weather station and then used for canopy evaporation estimation. This estimation was based on two approaches: the slope of the linear regression of gross rainfall against interception, or the Gash procedure (Ev1), and the Penman–Monteith equation (Ev2). Two rainfall interception models (Liu and Gash) were employed, using both Ev1 and Ev2. Thirty-two fixed rain gauges were used for Tf measurements and 32 trees were selected across species and diameter at breast height ranges for Sf observations. The revised version of the analytical Gash model underestimated I by -17.5% and -11.1% for Ev1 and Ev2, respectively, resulting in less accurate estimates. Based on these relative errors, the performance of the Gash model was classified as “fair.” The Liu model overestimated I by 5.3% and 11.3% for Ev1 and Ev2, resulting in assessments of “good” and “fair” respectively, and thus indicating improved performance compared to the Gash model. Therefore, the Liu model coupled with Ev1 is preferable for simulation of rainfall interception in semi-deciduous forests of the BAFB. However, slight overestimation bias was observed, and the model requires tweaking with respect to the estimation of forest storage capacity for this ecosystem. Interception loss modelling is a strategic tool for assessing the influence of different weather patterns and forest vegetative features on water balance in semi-deciduous forest ecosystems.

Thermo⁻Mechanical Behavior and Constitutive Modeling of In Situ TiB2/7050 Al Metal Matrix Composites Over Wide Temperature and Strain Rate Ranges.

The thermo–mechanical behavior of in situ TiB2/7050 Al metal matrix composites is investigated by quasi-static and Split Hopkinson Pressure Bar compression tests over a wide range of temperature (20~30 °C) and strain rate (0.001~5000 s−1). Johnson–Cook and Khan–Liu constitutive models determined from curve fitting and constrained optimization are used to predict the flow stress during deformation. In addition, another Johnson–Cook model calculated from an orthogonal cutting experiment and finite element simulation is also compared in this study. The prediction capability of these models is compared in terms of correlation coefficient and average absolute error. Due to the assumptions in orthogonal cutting theory, the determined Johnson–Cook model from cutting cannot describe the material deformation behavior accurately. The results also show that the Khan–Liu model has better performance in characterizing the material’s thermo–mechanical behavior.

Performance Evaluation of Hourly Solar Radiation Models on Inclined Surfaces in Longdong Area, China

Hourly global irradiations on tilted planes are required in various engineering calculations for solar systems which must be determined by converting the solar radiation intensities measured on a horizontal surface to the incident on the tilted surface of interest. There exist a large number of models designed to perform such a conversion. This paper presents the performance of five arithmetic models used to estimate solar irradiance on inclined surfaces. Utilizing solar radiation data from June to October measured in Longdong area of Gansu province, Model performance is assessed by an inter-comparison between the calculated and measured solar global radiation on a south-oriented surface tilted at 25°. Three statistical parameters (NMBE, NRMSE and R2) have been used to confirm the calculated values. The results show that the accuracy of the models is related to the sky conditions. Liu & Jordan model shows the best calculated performance under clear sky conditions, and Klucher model perform best under overcast and cloudy conditions. The other models included Perez, Hay and Skartveit & Olseth display an intermediary performance under all sky conditions. In order to estimate the tilt angle simply, two simple approximate equations (φ-15° model and Soulayman model) based on geographical latitude and solar declination are suggested for predicting daily optimum tilt angle in summertime.

Enhanced dyes adsorption from wastewater via Fe3O4 nanoparticles functionalized activated carbon.

Fe3O4 nanoparticles functionalized activated carbon (Fe3O4/AC) as an adsorbent was prepared and used for fast and effectively removing rhodamine B (RhB) and methyl orange (MO) from aqueous solution. Its physical and chemical properties characterized indicate that the adsorbent possesses abundant surface functional groups, sensitive magnetic response and enhanced specific surface area. Batch experiments were carried out to investigate the adsorption capacity and mechanisms. The obtained experimental data fitted well with the general-order kinetic equation and Liu's isotherm model with a maximum adsorption capacity of 182.48 mg g-1 for RhB and 150.35 mg g-1 for MO, respectively. The thermodynamic parameter was analyzed further and it showed an exothermic and spontaneous adsorption process. This composite with high adsorption efficiency and rapid magnetic separation can be a promising and recyclable adsorbent for practical wastewater treatment and purification processes.

Optical solitons to Chen–Lee–Liu model in birefringent fibers with modified simple equation approach

The Chen–Lee–Liu equation in birefringent fibers is examined to uncover quite important optical solitons of its. Dark, bright and also singular solitons in additionally singular periodic solutions are yield by modified simple equation technique with parameter restrictions.

Optical solitons to Chen–Lee–Liu model in birefringent fibers with trial equation approach

The Chen–Lee–Liu equation in birefringent fibers is examined to uncover quite important optical solitons of its. Dark, bright and also singular solitons in additionally singular periodic solutions are yield by trial equation technique with parameter restrictions.

Optical solitons to Chen–Lee–Liu model with trial equation approach

The Chen–Lee–Liu equation is examined to uncover quite important optical solitons of its. Dark, bright and also singular solitons in additionally singular periodic solutions are yield by trial equation technique with parameter restrictions.

Optical solitons to Chen–Lee–Liu model with modified simple equation approach

The Chen–Lee–Liu equation is examined to uncover quite important optical solitons of its. Dark, bright and also singular solitons in additionally singular periodic solutions are yield by modified simple equation technique with parameter restrictions.

Symmetry reductions, explicit solutions, convergence analysis and conservation laws via multipliers approach to the Chen–Lee–Liu model in nonlinear optics

In this paper, symmetry analysis is performed for the nonlinear Chen–Lee–Liu equation (NCLE) arising in temporal pulses. New forms of explicit solutions of the equation are constructed using the optimal systems by applying the power series solutions (PSS) technique and the convergence of the PSS is investigated. Finally, the conservation laws (Cls) of the model is studied using the multiplier approach.

Modelling the Effect of Heavy Metals on the Growth Rate of Enterobacter sp. Strain Neni-13 on SDS

The SDS-degrading bacterium Enterobacter sp. strain Neni-13 was strongly inhibited by mercury. Growth of the SDS-degrading bacterium at various concentrations of mercury shows a sigmoidal pattern with lag periods ranging from 7 to 10 h. As the concentration of mercury was increased, the overall growth was inhibited with 1.0 g/L causing an almost cessation of bacterial growth. The growth rates obtained from the modified Gompertz model was then modelled according to the modified Han-Levenspiel, Wang, Liu, modified Andrews and the Amor models. Out of the five models, only Wang, modified Han-Levenspiel and the Liu models were able to fit the curve, whilst the modified Andrews and Amor models were unable to fit the curves. Both the Wang and modified Han-Levenspiel models show acceptable fitting while the Liu model shows poor fitting. Results of the statistical analysis showed that the Wang model was the best model based on the lowest values for RMSE and AICc, highest adjusted correlation coefficient (adR2) and values of AF and BF closest to unity. The parameters obtained from the Wang model, which are Ccrit, max and m which represent critical heavy metal ion concentration (g/l), maximum growth rate (g/l h) and empirical constant values were 0.216 (95%, confidence interval f 0.193 to 0.239), 1.05 (95%, confidence interval of 0.938 to 1.167) and 0.389 (95%, confidence interval of 0.148 to 0.636) respectively.

Determining the Optimum Tilt Angles to Maximize the Incident Solar Radiation - Case of Study Pristina

Solar energy is derived from photons of light coming from the sun in a form called radiation. Solar energy finds extensive application in air and water heating, solar cooking, as well as electrical power generation, depending on the way of capturing, converting and distribution. To enable such application, it is necessary to analyze the horizontal tilt angle of horizontal surfaces – in order that when the solar energy reaches the earth surface to be completely absorbed. This paper tends to describe the availability of solar radiation for south-facing flat surfaces. The optimal monthly, seasonal, and annual tilt angles have been estimated for Pristina. The solar radiation received by the incident plane is estimated based on isotropic sky analysis models, namely Liu and Jordan model. The annual optimum tilt angle for Pristina was found to be 34.7°. The determination of annual solar energy gains is done by applying the optimal monthly, seasonal and annual tilt angles for an inclined surface compared to a horizontal surface. Monthly, seasonal and annual percentages of solar energy gains have been estimated to be 21.35%, 19.98%, and 14.43%. Losses of solar energy were estimated by 1.13 % when a surface was fixed at a seasonal optimum tilt angle, and when it was fixed at an annual optimum tilt angle, those losses were 5.7%.Article History: Received February 15th 2018; Received in revised form May 12th 2018; Accepted June 2nd 2018; Available onlineHow to Cite This Article: Berisha, Xh., Zeqiri, A. and Meha, D. (2018) Determining the Optimum Tilt Angles to Maximize the Incident Solar Radiation - Case of Study Pristina. Int. Journal of Renewable Energy Development, 7(2), 123-130.https://doi.org/10.14710/ijred.7.2.123-130

Summary of the General Discussion on “The Effect of an Introduction of Retail Sales Tax in China”

June 01 2018 Summary of the General Discussion on “The Effect of an Introduction of Retail Sales Tax in China” Author and Article Information Online Issn: 1536-0083 Print Issn: 1535-3516 © 2018 by the Asian Economic Panel and the Massachusetts Institute of Technology2018Massachusetts Institute of Technology Asian Economic Papers (2018) 17 (2): 24. https://doi.org/10.1162/asep_a_00603 Cite Icon Cite Permissions Share Icon Share Facebook Twitter LinkedIn MailTo Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Search Site Citation Summary of the General Discussion on “The Effect of an Introduction of Retail Sales Tax in China”. Asian Economic Papers 2018; 17 (2): 24. doi: https://doi.org/10.1162/asep_a_00603 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsAsian Economic Papers Search Advanced Search Suresh Narayanan commented that China has a strange value-added tax (VAT) in that it does not zero-rate agricultural products. Therefore, results cannot be generalized. Substituting VAT for business taxes is not heard of. He pointed out that a 5 percent decline in retail sales tax (RST) coupled with a 5 percent increase in VAT will not result in the same amount of government revenue collected because VAT has exemptions and thus the RST has to change more to result in revenue neutrality. The RST has a single collection point only, whereas the VAT has multiple collection points. Li and Liu's model does not take care of this difference in feature. Furthermore, Narayanan asked whether this model applies when there are no labor market frictions. He suggested that the model be extended in this direction. The authors agreed with Narayanan's observation that a decline in VAT and an increase in RST... You do not currently have access to this content.

Borosilicate and Polyurethane as Materials for Lenses to Correct Human Presbyopia

Start your abstract here The novel of this paper is, using gradient refractive index and spherical surfaces to design a bifocal polyurethane lens with single power instead of the previous designs, which consist of two lens with different powers to correct the vision of near and medium distances at the same time. Presbyopia occurs naturally as eyes age and the structure of the lens responsible for focusing images changes. Presbyopia treatments include corrective lenses like eyeglasses known as progressive lenses. The aims of this work were to evaluate the performance of the human eye after the treatment by using different gradient refractive glass materials. Zemax was used to design an optical system for human eye based on Liu & Brennan model. Two types of optical materials, namely, borosilicate and polyurethane, were selected to design a multifocal lens. The effects of these materials on the performance of the human eye were compared to select the best material. Three different criteria were used; minimum root mean square error, the modulation transfer function and the diffraction image analysis. Modulation transfer function and root mean square Results show that the polyurethane lens is more suitable than the borosilicate lens for correcting presbyopia. Polyurethane material lens gave a better eye performance in three distances, namely, farther, intermediate, and near than the borosilicate lens. Polyurethane lens could be used as trifocal while borosilicate work only as Bifocal lens. The Results suggested that by using only one polyurethane lens power with gradient refractive index and a variable conic for lens curvature in Zemax corrected the vision of distance, near and medium distances at one time.

Are uncertainty shocks aggregate demand shocks?

This note considers the Leduc and Liu (JME, 2016) model and studies the effects of their uncertainty shock under different Taylor-type rules. It shows that both the responses of real and nominal variables highly depend on the Taylor rule considered. Remarkably, inflation reacts positively so that uncertainty shocks look more like negative supply shocks, once an empirically plausible degree of interest rate smoothing is taken into account. This result is reinforced with less reactive monetary rules. Overall, these rules alleviate the recession.

Solar energy potential estimation by calculating sun illumination hours and sky view factor on building rooftops using digital elevation model

The detailed and precise estimation of solar energy is a major requirement for solar applications on building roof tops. These estimations help in sustainable development, energy policy making, and renewable energy consumption. In this paper, a methodology was devised to estimate the solar radiation components. This methodology is easily accessible using a simple measuring tape to form a digital elevation model with a cell size of 1 × 1 sq. ft. Liu and Jordan's model [Liu and Jordan, “The interrelationship and characteristic distribution of direct, diffuse and total solar radiation,” Sol. Energy. 4(3), 1–19 (1960)] was modified for the urban environment and programmed in MATLAB to estimate solar potential. To validate the developed algorithm and modified model, the roof-top area of the postgraduate laboratories of the Mechanical Engineering Department (NED University) was selected as a case study. Measurements were carried out on different days, which showed good agreement with the proposed work. Within the study area, the maximum sunshine hours is 3285 annually, while the site selected has at least 1502 sunshine hours irrespective of elevations. Similarly, the sky view factor has a maximum value of 1 exposed to open plain and a minimum value of 0.4143. Radiation maps were generated for the installation of solar applications. The results showed that the average beam radiation was 4.908 kWh/m2, with May and December having the maximum and minimum beam intensities of 6.679 kWh/m2 and 3.815 kWh/m2, respectively. Similarly, the average diffuse radiation was 2.289 kWh/m2, with maximum and minimum values, occurring in July and October, of 3.611 kWh/m2 and 1.299 kWh/m2, respectively. This work will help energy consultants and households in determining the solar energy potential of the existing flat rooftops and for future construction, thereby cutting energy bills and producing long-term monetary incentives from generating their own energy.

Chirped optical solitons of Chen–Lee–Liu equation by extended trial equation scheme

This paper employs the extended trial equation method to retrieve chirped optical soliton solutions to Chen–Lee–Liu model that describes pulse propagation through optical fibers. Bright and singular optical soliton solutions are recovered by the application of this algorithm. As a byproduct, singular periodic solutions fall out. These soliton solutions are obtained with constraint conditions that are also presented.

A comparative investigation on motion model of spherical fragments penetration into gelatin

Gelatin is a popular tissue simulant in biomedical applications. The behavior of a spherical fragment and the effects of penetrating a simulant are similar in biological tissue. In order to accurately describe the interaction between a spherical fragment and muscle tissue, this paper discusses the wounding mechanism and the difference between the Sturdivan model, the Segletes model, the Liu model, and an improved motion model previously established considering the effect of strain rate by us based on the properties of gelatin. In addition, experiments conducted into spherical fragment penetration into gelatin, with fragment diameters 3, 4 and 4.8 mm, and acquisition of the corresponding motion law are discussed. Numerical calculations reveal that the motion model has a better fit with experimental values than the Sturdivan, Segletes and Liu models. Further, it more accurately describes the motion of a spherical fragment penetrating gelatin than other models and also has good generality. Thus, it can provide a theoretical reference for small arms ammunition design and wound treatment.

Best Tilt Angle of Fixed Solar Conversion Systems at M’Sila Region (Algeria)

Abstract: The position of the solar conversion systems relative to the sun affects directly their energy output. Optimum tilt angle is the inclination which maximizes the amount of intercepted solar energy. This paper aims to find the best inclination angle of fixed solar conversion systems in M’Sila region, (monthly, seasonally and annually) theoretically (using empirical models namely; Liu & Jordan model, circumsolar model, Hay model, and Reindl model) and experimentally. Reindl model is the most suitable for M’Sila region because, it gives values close to those found experimentally. It is preferable to change the tilt angle of solar conversion systems monthly or seasonally instead of fixing them, to gain more energy.

Modelling the Effect of Copper on the Mo-reduction Rate of the Antarctic Bacterium Pseudomonas sp. strain DRY1

Molybdenum reduction by the Antarctic bacterium Pseudomonas sp. strain DRY1 is strongly inhibited by copper. Mo reduction by this bacterium at 10 mM sodium molybdate shows a sigmoidal pattern with lag periods ranging from 7 to 10 h at various concentrations of copper. As the concentration of copper was increased, the overall Mo reduction rate was inhibited with 1.2 mg/L causing the cessation of Mo reduction rate. The modified Gompertz model was utilized to obtain Mo reduction rates at different concentrations of copper. The Mo reduction rates obtained from the modified Gompertz model was then modelled according to the modified Han-Levenspiel, Wang, Liu, modified Andrews and the Amor models. Out of the five models, only Wang, modified Han-Levenspiel and the Liu models were able to fit the curve, whilst the modified Andrews and Amor models were unable to fit the curves. Both the Wang and modified Han-Levenspiel models show acceptable fitting while the Liu model shows poor fitting. Results of the statistical analysis showed that the modified Han-Levenspiel model was the best model based on the lowest values for RMSE and AICc, highest adjusted correlation coefficient (adR2) and values of AF and BF closest to unity. The parameters obtained from the modified Han Levenspiel model, which were Ccrit, max and m which represent critical heavy metal ion concentration (mg/l), maximum reduction rate (nmole Mo blue/h) and empirical constant values were 0.225 (95%, confidence interval from 0.198 to 0.251), 1.200 (95%, confidence interval from 1.180 to 1.220) and 0.443 (95%, confidence interval from 0.261 to 0.626). The modified Han-Levenspiel accurately predicted the critical copper concentration that completely inhibited molybdenum reduction rate in this bacterium.

Kinetics, isotherm, and thermodynamic studies of methylene blue adsorption from water by Mytella falcata waste.

This work evaluates the application of Mytella falcata shells, discarded in large quantities in the state of Alagoas, Brazil, as adsorbent for methylene blue dye (MB). It was investigated how the amount of adsorbent (M), the average particle diameter (G), and the agitation speed (A) affected the adsorption. Kinetic and equilibrium studies were conducted, and the pseudo-second-order equation adequately represented the kinetic data and isotherms following Liu's model (q max=8.81mgg-1 at 60°C). The adsorption was spontaneous, favorable, and endothermic. Mytella falcata shell is a suitable adsorbent for MB and could potentially contribute to its removal from the environment.