Search

Recent studies with the new program RoseBoom© claim it can predict reliable detonation parameters only based on the structural formula, without the need of a heat of formation or density obtained using a different method. In this study, it was investigated how big the impact on the calculated detonation parameters is, when one uses the density and heat of formation predicted by RoseBoom2.2© vs. densities and the heat of formations published with the corresponding molecules. A range of traditionally used models in terms of the sensitivity to the accuracy to the input values is tested. Furthermore, it proofs the need to agree on one software for predicting the performance of energetic materials, starting with the input of values of energetic materials. Additionally, it puts further trust into the predictions by RoseBoom© and raises awareness of the uncertainty of published performance values. [ABSTRACT FROM AUTHOR]

DNI assessment is essential for developing any CSP projects. In this manuscript, an approach is made for the analysis and estimation of DNI by developing the empirical models for India. The historical data of around 15 years (1986-2000) of DNI and cloud cover (CC) from six representative locations of major climatic zones namely Bhopal, Jaipur, Srinagar, Patna, New Delhi & Thiruvanantpuram have been employed. From these locations, first four have been used to develop the models correlating DNI and cloud cover; however, rest two were used to evaluate their validity. The standard statistical predictor's viz. CoD, MPE, MBE, RMSE, skewness, kurtosis & chi-square were applied to evaluate these empirical models. The CoD was observed greater than 0.8 while performance criteria have low and acceptable values (MPE-11.4% to -13.77%; MBE 0.49 to 0.96; RMSE 1.22 to 1.44; Skewness 0.90 to -0.15; Kurtosis 0.90 to -1.36 and Chi-square 6.87 to 8.50). The adequecy of empirical models was evaluated through comparing estimated and measured DNI for New Delhi and Thiruvanantpuram which coincides very closely. The study established an approach to estimate DNI using cloud cover data which may facilities CSP projects developers for site selection and decision making in the absence of ground data. [ABSTRACT FROM AUTHOR]

This paper presents empirical models for the frequency content parameters of offshore ground motions in the Japan Trench area based on the S-net dataset, comprising 6,436 recordings from 496 events. Significant variations in frequency content among shallow crustal, upper-mantle, subduction interface and subducting slab are revealed. Empirical models for To, Tavg, and Tm are proposed, considering moment magnitude, source distance, focal depth, and tectonic types. A comparative analysis with four existing land models highlights differences. Total residual results indicate that land models, based on shallow crustal datasets, tend to overestimate observed frequency content parameters in the Japan Trench area. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the predictive ability of NIRS for the estimation of the chemical composition and organic matter digestibility (OMD) of total mixed rations (TMR) for dairy cows. Moreover, herein, empirical equations based on chemical parameters were developed for calculating the OMD. Samples were collected from Galician dairy farms and were scanned in duplicate a Foss NIRSystem 6500 monochromator (1100-2500 nm). The predictive ability of NIRS models was evaluated according to the coefficient of determination in external validation ( r 2). High r 2 (equal to or higher than 0.90) was shown in predicting chemical composition, however, the estimation of OMD was acceptable ( r 2 = 0.83). The ability of the NIRS models for estimating the chemical composition was considered excellent, with the ratio performance deviation of external validation ( R P D) higher than 3.0, allowing for quantitative predictions. The estimation of the OMD value by NIRS was considered acceptable ( R P D = 2.5), and led to reduction in the standard error of external validation, in comparison of the best empirical model based on the chemical composition of samples (from ± 2.06% to ± 1.89%). Therefore, this study demonstrated that the NIRS is an effective technology for the rapid and precise nutritional evaluation of TMR in Galicia. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to introduce a novel approach to empirical modelling for the prediction of propagation pathloss, in wireless radio communication systems. The method, here referred to as the 'Quasi-Moment-Method' (QMM), has its basis in the solution of the classical least square approximation problem, in a manner similar to the method of moments, for the solution of electromagnetic field problems. By using existing basic models to prescribe 'basis' functions, associated unknown coefficients are determined through the solution of simple matrix equations. A comparative analysis with some published measurement data revealed that the QMM consistently outperformed models developed with other approaches. Typically, the ECC-33 models, modified using the QMM, for an outdoor case, recorded a root-mean-square-error value of 0.33 dB, as against 20.083 dB due to a corresponding published optimised model. [ABSTRACT FROM AUTHOR]

The increasing importance of CO2 in reservoir engineering demands more accurate models for predicting interfacial tension (IFT). We investigated the use of neural networks to predict the IFT of ternary systems CO2/CH4/Water-Brine in a wide range of reservoir conditions, since the existing correlations do not capture all of the system's mechanisms. We introduced an optimization associated with k-fold cross validation to find optimal architecture and ensure an unbiased model. The average absolute relative error obtained is 1.33% (water) and 1.99% (brine) considerably more accurate than the best empirical models tested: 9.87% (water) and 19.11% (brine). Molecular dynamics simulation performed confirms the high superficial activity of CO2. [ABSTRACT FROM AUTHOR]

Turbulent bed contactors (TBC) are three-phase fluidized beds which form an important class of process equipment used in many applications. In this work, experiments were conducted to investigate bed expansion and gas holdup behavior in TBC with non-Newtonian fluid for which limited information is reported in the literature. Aqueous solutions of carboxymethyl cellulose (CMC) with apparent viscosities ranging from 5 to 25 mPa.s were sprayed over beads packing at the top of the column. Forced airflow entered the bottom of the column to fluidize hollow plastic beads. The effect of rheological properties of CMC aqueous solutions on bed expansion and gas holdup was investigated upon variations of operating conditions. Two regions of bed expansion were existing when liquid flow rates were lower than 5.05 × 10−4 m3/s. Gas holdup decreased drastically for more viscous liquid solutions. Empirical models were developed for important hydrodynamic parameters of TBC such as pressure drop, liquid holdup, minimum fluidization velocity, and bed expansion as a function of several operational variables. Different dimensionless groups were formed from the available set of variables and empirical models were proposed and fitted based on maximum R2 criteria. The models developed can be used in the design and optimal operation of TBC. [ABSTRACT FROM AUTHOR]

This paper contributes to the empirical research around the "wage-led" or "profit-led" demand regimes. It first reviews how Kalecki, and then Steindl, approached the relationship between economic growth and income distribution. Then, empirical analysis carried out under the probabilistic approach to econometric modeling shows statistical evidence, estimated through cointegration analysis, that in the long run, in three very open economies—Mexico, France, and Korea—the wage share is positively associated with demand and output. It finally discusses the macroeconomic dilemma that almost all countries have to face, i.e., a positive effect of a high-wage policy on demand and employment may diverge from a negative effect on output compatible with external equilibrium. [ABSTRACT FROM AUTHOR]

The heat transfer in liquid metal-cooled rod bundles is modeled with a knowledge-based best-estimate system code. Thereby, the focus is on the heat transfer enhancement due to flow perturbations. These perturbations are caused by local geometrical variations, such as sudden expansions and contractions, in the flow channel. The accurate calculation of the heat transfer is important for the safety demonstration of, e.g., subassemblies. Safety-related parameters, such as fluid and wall temperature, have to satisfy certain limits during normal and off-normal operation as well as during accidents. Up to now, fully developed flow is assumed for heat transfer in liquid metal-cooled rod bundles. The effects of local heat transfer enhancements were ignored in best-estimate system codes. The currently used empirical heat transfer models are functions of the Péclet number only. Several experimental and numerical investigations show that flow perturbations induce higher heat transfer due to increased turbulences, accelerated flows, and secondary motions. In this paper, the effects of the entrance region and the presence of spacer grids on the heat transfer are investigated. Empirical models for that are selected and applied. These empirical models are functions of the Péclet number, the geometrical perturbation, and the distance from the perturbation in the flowing direction. The calculated heat transfer coefficients at the bundle entrance and in the vicinity of spacer grids are twice as high compared to bare rod bundles under a fully developed flow condition without any flow perturbation. Because of the higher heat transfer, lower wall temperatures are to be expected. This provides additional safety margins during normal and off-normal operation as well as during accidents. Furthermore, the considerable increase of heat transfer shows that existing perturbations have to be considered to obtain accurate and reliable results. [ABSTRACT FROM AUTHOR]

In this study, 54 empirical models including 22 new models were used to estimate the global solar radiation on horizontal surface. The data were collected in Dohuk cities in the northern Iraq. The evaluated models are based on sunshine duration, air temperature, cloud cover, and other meteorological parameters. In the investigated region, the statistical error indicators value for all empirical models of R, R2, mean absolute bias error, root mean square error, mean absolute percentage error, Nash-Sutcliffe equation, and t-test value were low and within an acceptable range. The results of Model 49 based on the other meteorological parameters which is newly developed model with equation of had the most appropriate result with a value of R2 (0.9942) in the 54 empirical models. Besides, 22 new equation models are produced based on sunshine hours, air temperature, and other meteorological parameters. The best accuracy among the new equation was observed in Model 49. Furthermore, the Models 34, 12, and 25 based on cloud cover, sunshine hour, and air temperature in terms of data accuracy were ranked, respectively. [ABSTRACT FROM AUTHOR]

The study aims to evaluate the performance of different empirical soil erosion models (EPM, USLE, Koutsoyiannis and Tarla, RUSLE) in mountainous Mediterranean-type catchments. The study area comprises the Arachthos, Kalamas, Upper Acheloos and Venetikos river basins, located in northwestern Greece. The methodology followed includes both qualitative and quantitative analyses. The former refers to the specific attributes of the models and the latter to the estimated sediment yield results. The results were initially validated against observed sediment yield values. The ambiguous reliability of such measurements led to their replacement by simulated ones, estimated using the sediment rating curve methodology. In the latter analysis, the models performed better, with more accurate results. Overall, the RUSLE corresponded best to such basins. Finally, the performance of seven empirical equations (Syvitski, Avendano Salaset al., Dendy and Bolton, Luet al., Webb and Griffiths, Zarriset al.) was assessed, yielding relatively poor results. [ABSTRACT FROM AUTHOR]

Miombo woodlands cover large areas in Tanzania but very little reliable data on forest dynamics for the woodlands exist. The main objective of this study was to develop a model system describing such dynamics based on easily measurable tree variables. Individual tree diameter growth and mortality models, and area-based recruitment models were developed. The modelling was based on data from 117 permanent sample plots established between 1997 and 2009 on seven sites in the Iringa and Manyara regions. The data set comprised 2 314 trees at establishment and 4 758 observations of individual tree growth, and covered a large number of species (141). Based on diameter growth and by using a model-based clustering procedure, three tree species groups were developed. Several model forms with different independent variables were tested. Simple and robust models with few independent variables, which agreed with expected biological behaviour, were finally selected. Although biological behaviour was the principal model selection criterion, the models also performed well statistically. The developed model system, which is the first of its kind for miombo woodlands in Africa, may be used to develop a decision-support tool for practical forest management planning in the country. [ABSTRACT FROM PUBLISHER]

Relationships among selected performance properties have been established using experimental data from a cement-stabilized mixed contaminated soil. The sandy soil was spiked with 3,000 mg/kg each of Cd, Cu, Pb, Ni and Zn, and 10,000 mg/kg of diesel. It was then treated with 5%, 10%, 15%, and 20% dosages of Portland cement. Different water contents were considered for lower dosage mixes. Selected geotechnical and leaching properties were determined on 28-day old samples. These include unconfined compressive strength (UCS), bulk density, porosity, hydraulic conductivity, leachate pH and granular leachability of contaminants. Interrelationships among these properties were deduced using the most reasonable best fits determined by specialized curve fitting software. Strong quadratic and log-linear relationships exist between hydraulic conductivity and UCS, with increasing binder and water contents, respectively. However, the strength of interrelationships between hydraulic conductivity and porosity, UCS and porosity, and UCS and bulk density varies with binder and water contents. Leachate pH and granular leachability of contaminants are best related to UCS and hydraulic conductivity by a power law and an exponential function, respectively. These results suggest how the accuracy of not-easily-measurable performance properties may be constrained from simpler ones. Comparisons with some published performance properties data support this. [ABSTRACT FROM PUBLISHER]

This study assessed the performance of six solar radiation models. The objective was to determine the most accurate model for estimating global solar radiation on a horizontal surface in Nigeria. Twenty-two years meteorological data sets collected from the Nigerian Meteorological agency and the National Aeronautics and Space Administration for the three regions, covering the entire climatic zones in Nigeria were utilized for calibrating and validating the selected models for Nigeria. The accuracy and applicability of various models were determined for three locations (Abuja, Benin City, and Sokoto), which spread across Nigeria using seven viable statistical indices. This study found that the estimation results of considered models are statistically significant at the 95% confidence level, but their accuracy varies from one location to another. However, the multivariable regression relationship deduced in terms of sunshine ratio, air temperature ratio, maximum air temperature, and cloudiness performs better than other relationships. The multivariable relationship has the least root mean square error and mean absolute bias error, not exceeding 1.0854 and 0.8160 MJ m−2day−1, respectively, and monthly relative percentage error in the range of ± 12% for the study areas. [ABSTRACT FROM PUBLISHER]

Actual evapotranspiration/evaporation is essential in proper determination of potential recharge of semi-arid regions. Eight potential evapotranspiration methods with dual crop coefficient methodology were used to estimate actual evaporation (Ea) values from bare soil. Method comparison with measuredEavalues using lysimeter data for the hydrological years 2011/12 and 2012/13 identified better performance for the FAO-56-Penman-Monteith (NRMSE < 9%), Hargreaves-Samani (NRMSE < 13%), Priestley-Taylor (NRMSE < 15%) and Makkink (NRMSE < 14%) methods. Data of 2011/12, bestEaestimates and a water balance approach were used to calibrate six potential recharge models with linear, quadratic, exponential, cubic and power functions. Calibrated models were validated in simultaneous estimation of potential recharge and soil moisture using independent data for 2012/13. While models with linear/quadratic functions produced the weakest potential recharge estimates (ΔQ> 10%), the remaining models were acceptable. Soil moisture was acceptably simulated utilizing six models and four best evaporation methods (NRMSE < 20%). However, combination of the FAO-56-Penman-Monteith model with an exponential function produced the bestEavalues, soil moisture and potential recharge. [ABSTRACT FROM AUTHOR]

This paper focuses on the development of experimental relationships between the microstructure and mechanical properties of a sand cast ductile iron and on the design of a direct ‘in mould’ thermal analysis system for heavy section castings. The casting system was developed in order to obtain different thermal modules, and it has been studied by numerical simulation. The microstructure was estimated through numerical models implemented in a commercial casting simulation code and validated by comparing simulated and experimental data obtained from more than 2000 optical micrographs considering nodularity, density and size of nodules, fractions of graphite, ferrite and pearlite. Empirical relationships between the microstructure and mechanical properties were developed and then implemented in the simulation software in order to evaluate the local mechanical properties. The results of hardness and tensile tests carried out on samples extracted from the castings showed good accordance between predicted and measured mechanical properties. [ABSTRACT FROM PUBLISHER]

Modeling is an important tool in the food industry since it is able to simplify explanation of phenomena and optimize processes that cover a broad field from manufacture to byproducts treatment. The goal of the current article is to explore the development of enzyme kinetic models and their evolution over the last decades. For this reason, corresponding simulations were classified in deterministic, empirical, and stochastic models, prior investigating limitations, corrections, and industrial applications in each case. The ultimate goal is to provide an answer to a major problem: how can we develop an intermediate complexity model that achieves satisfactorily representation of the main phenomena with a limited number of parameters? [ABSTRACT FROM AUTHOR]

Most Latin American glaciers are located in the tropical Andes. The melting processes of Glacier “15” on Antisana volcano were studied to understand the relationship between glacier retreat and natural climate variability and global climate change. Glaciers on the Antisana volcano are crucial sources of water as they feed the headwater rivers that supply Quito with potable water. The aim of this study was to build empirical models based on multiple correlations to reconstruct the mass loss of glaciers over a period of 10 years at three scales: local (data recorded by meteorological stations located around the volcano), regional (data from stations located around the country) and global (re-analysis data). Data quality was checked using graphical and statistical methods. Several empirical models based on multiple correlations were created to generate longer time series (42 and 115 years) of the mass balance for the glacier ablation zone. The long mass balance series were compared with the temperature variation series of the Earth’s surface in the Southern Hemisphere to estimate the relation between the mass balance and global warming. Our results suggest that the meteorological factors that best correlate with mass balance are temperature and wind.Editor D. KoutsoyiannisCitation Manciati, C., Villacís, M., Taupin, J.-D., Cadier, E., Galárraga-Sánchez, R., and Cáceres, B., 2014. Empirical mass balance modelling of South American tropical glaciers: case study of Antisana volcano, Ecuador. Hydrological Sciences Journal, 59 (8), 1519–1535. http://dx.doi.org/10.1080/02626667.2014.888490 [ABSTRACT FROM PUBLISHER]

The prediction of propagation loss is a practical non-linear function approximation problem which linear regression or auto-regression models are limited in their ability to handle. However, some computational Intelligence techniques such as artificial neural networks (ANNs) and adaptive neuro-fuzzy inference systems (ANFISs) have been shown to have great ability to handle non-linear function approximation and prediction problems. In this study, the multiple layer perceptron neural network (MLP-NN), radial basis function neural network (RBF-NN) and an ANFIS network were trained using actual signal strength measurement taken at certain suburban areas of Bauchi metropolis, Nigeria. The trained networks were then used to predict propagation losses at the stated areas under differing conditions. The predictions were compared with the prediction accuracy of the popular Hata model. It was observed that ANFIS model gave a better fit in all cases having higherR2values in each case and on average is more robust than MLP and RBF models as it generalises better to a different data. [ABSTRACT FROM PUBLISHER]

In this work, water activity (aw), moisture loss, and salt uptake as mass transfer in osmotic dehydration (OD) of Cyprinus carpio fillets were analyzed. Two highly concentrated solutions were used for the OD: binary (NaCl-water) and ternary (NaCl-sucrose-water) solutions at 20°C. Both solutions had the same NaCl concentration, but the second also had sucrose (2:1) which improved water loss and reduced NaCl gain. Among the OD models analyzed, Peleg's equation presented the best fit with the ternary solution (R2> 0.900), while the Zugarramurdi and Lupín did so for the binary solution treatment (R2> 0.950). Page's model presented good fit for water release in both cases (R2> 0.950). [ABSTRACT FROM PUBLISHER]

To analyze the systems working with solar energy, it is required that values of the solar radiation belonging to the region have been known. The global solar radiation on a horizontal surface has been measured by the Turkish State Meteorological Service over all of the country, while the diffuse solar radiation has not been measured. In this study, empirical correlations are developed to establish a relationship between the monthly average daily diffuse fraction (Hd/H) and monthly average daily diffuse coefficient (Hd/Ho) with the monthly average daily clearness index (KT = H/Ho) for the province of Erzurum, Turkey. The six new models for estimating the monthly average daily diffuse solar radiation on a horizontal surface for Erzurum are validated, and the new models are then compared with the 10 models available in the literature. In order to indicate the performance of the models, the statistical test methods of relative percentage error, mean bias error, mean absolute bias error, mean relative error, root mean square error, and correlation coefficient are used. The results indicated that the correlations developed in the study predict diffuse solar radiation reasonably well for future projections. [ABSTRACT FROM PUBLISHER]

The performance of the ab initio and density functional theory (DFT) functional, B3LYP and PBEPBE, in conjunction with selected basis sets for the prediction of 31P shielding constants for small phosphorous-containing molecules is assessed. The effects of applied factors are discussed. By including the electron correlation treatment, B3LYP and PBEPBE are the most accurate methods to compute the chemical shielding for a set of small phosphines that was studied. Also, additional improvements of DFT were obtained by empirical scaling of basis sets in calculation of chemical shifts. For molecules containing only phosphorous and carbon atoms with sp3 hybridization, the PBEPBE/6-311G(d,p) level of theory has been shown to provide reliable 31P chemical shifts. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT [ABSTRACT FROM AUTHOR]

Rainfall-runoff models usually present good results, but parameter calibration sometimes is tedious and subjective, and in many cases it depends on additional data surveys in the field. An alternative to the conceptual models is provided by empirical models, which relate input and output by means of an arbitrary mathematical function that bears no direct relationship to the physical characteristics of the rainfall-runoff process. This category includes the artificial neural networks (ANNs), whose implementation is the main focus of this paper. This study evaluated the capacity of ANNs to model with accuracy the monthly rainfall-runoff process. The case study was performed in the Jangada River basin, Parana, Brazil. The results of the three ANNs that produced the best results were compared to those of a conceptual model at monthly time scale, IPHMEN. The ANNs presented the best results with highest correlation coefficients and Nash-Sutcliffe statistics and the smallest difference of volume. Citation Machado, F., Mine, M., Kaviski, E. & Fill, H. (2011) Monthly rainfall-runoff modelling using artificial neural networks. Hydrol. Sci. J. 56(3), 349-361. [ABSTRACT FROM AUTHOR]

Vacuum microwave dehydration characteristics and drying kinetics of potato slices were evaluated using a laboratory-scale dryer. The test materials were placed on a rotating tray to allow uniform exposure to the microwave field. The effect of drying conditions on the drying characteristics was investigated. As expected, higher drying rates were obtained with higher microwave power and lower vacuum levels. The effect of vacuum pressure on drying rate was not as significant as that of microwave power. The Henderson & Pabis model provided better simulation of the drying curves for potato slices. Empirical models are presented for the drying rate constant as a function of the microwave power and vacuum pressure for potato slices under the range of operating conditions tested. [ABSTRACT FROM AUTHOR]

A review of the literature has revealed the lack of a formal analysis of the performance of empirical methods for the prediction of pressure volume temperature (PVT) properties of Niger delta crude oils. This study presents an assessment of the predictive accuracy of five bubble-point pressure (Pb) correlations and five bubble-point oil formation volume factor (Bob) correlations against a large measured PVT data bank from Niger Delta crude oils. Statistical analysis techniques were used to evaluate the performance and the accuracy of the commonly used empirical models for estimating PVT properties of Niger crude oil in order to guide designers and operators in selecting the best correlations for their particular applications. Agreement between calculated and measured Pb and Bob values for the various models was very poor. The model predictions of Pb and Bob can be different from the measured values by 56% and 242%, respectively. Development of improved models for predicting the PVT properties of Niger delta crude oils is urgently required. [ABSTRACT FROM AUTHOR]

Remote sensing techniques can be used to quantify the total suspended matter concentration (TSM). The main objective of this study is the quantification of the TSM concentration around the sea breaking zone for a particular area of the Portuguese coast, near Aveiro city. The methodology used was based on in situ measurements and on multispectral satellite image from TERRA/ASTER. In situ experimental techniques were used to determine a relationship between the TSM concentration and the seawater reflectance. Empirical relationships were established between TSM concentration and the equivalent reflectance values for TERRA/ASTER at visible and near infrared bands computed from the experimental data. The reflectance values had a very high correlation with the TSM concentration in the wavelength between 500 and 900 nm. The ASTER image was calibrated, atmospherically and geometric corrected. Equations of linear, polynomial, logarithmic, power and exponential models were applied. The best results were found with the linear and polynomial models, with a determination factor higher than 0.95. However, the differences in the TSM concentration calculated for the three bands indicate that we should not use the information of a single band to obtain the TSM concentration. [ABSTRACT FROM AUTHOR]

Solar engineers, architects, agriculturists, and hydrologists dealing with many applications of solar energy require a reasonably accurate knowledge about the availability of solar resources at any place. For this purpose, in the past, several empirical correlations have been developed in order to predict the solar radiation around the world. The present study, consisting of two parts, analyzes global solar radiation over the Central Anatolia Region (CAR) of Turkey along with its twelve provinces. Part 1 of this study includes the solar radiation models developed, while their statistical analysis is presented in Part 2. In the analysis, the data of the monthly average daily global solar radiation and sunshine duration measured by the Turkish State Meteorological Service in the period from January 1990 to December 1996 are used. Empirical models to estimate the monthly global solar radiation on a horizontal surface for each province are developed. The results obtained have indicated that the models developed here predict solar radiation reasonably well for future projections. [ABSTRACT FROM AUTHOR]

The aim of the article is to investigate the determinants of patent citations which are reasonably good proxy for the technological value of an invention. The analysis is based on patents granted by the US Patent and Trademark Office (USPTO) to French and British inventors from 1969 to 1998. Our aim is to explain the frequency of citations rather than why a patent may or may not be cited. This is achieved by examining some of the characteristics associated with highly cited patents. The models we estimate predict that a patent that is frequently cited, and therefore a technologically important patent, is a patent that it is quickly cited and more frequently cited by patent from other technological fields. When the patent is cited by patents from other technological fields this tends to indicate that the cited patent is broader. [ABSTRACT FROM AUTHOR]

This paper presents various methods to assess nitrous oxide emissions from soils in response to the nitrogen input in agriculture (grassland and arable land) and in forests, using available measurements and results of detailed process-based and more simple and empirical modelling approaches. The measurements and modelling approaches focus on Europe and specifically the Netherlands. Both measurements and model applications indicate that default emission factors for N2O emissions are an underestimate for fertilizer and manure application on organic soils and for N deposition on forests. These results illustrate the potential of measurements and models to improve default IPCC Good Practice Guidance emission factors. Validated detailed process oriented biogeochemical models are furthermore useful to extrapolate results of measurements to other combinations of land use, soil type and management practices, whereas more simplified models have a large potential to extrapolate N2O emission estimates to the regional and national scale. Use of both types of models is essential to improve detail and precision in national N2O emission inventories. [ABSTRACT FROM AUTHOR]

Solar energy occupies one of the most important places among the various possible alternative energy sources. In the design and study of solar energy, information on solar radiation and its components at a given location is very essential. In other words, a reasonably accurate knowledge of the availability of the solar resource at any place is required by solar engineers, architects, agriculturists, and hydrologists in many applications of solar energy such as solar furnaces, concentrating collectors, and interior illumination of buildings. For this purpose, in the past, several empirical correlations have been developed in order to estimate the solar radiation around the world. The main objective of the present study is to review solar radiation models available in the literature for both Turkey in general and some of the provinces. In this regard, a total of 41 models developed between 1983-2002 was given. Of this, 15 models were for the whole of Turkey, while the remainder were for some of Turkey's provinces such as Antalya, Elazig, Gebze, Istanbul, Izmir, Konya and Trabzon. It may be concluded that the models investigated predict the solar radiation reasonably well for the projections. [ABSTRACT FROM AUTHOR]

Solar engineers, architects, agriculturists, and hydrologists in many applications of solar energy require a reasonably accurate knowledge about the availability of solar resources at any place. For this purpose, in the past, several empirical models have been developed in order to estimate the solar radiation around the world. The main objective of the present study is twofold, namely: (1) to compare some existing models used for estimating the monthly average daily global solar radiation on a horizontal surface (H) for Turkey's big cities such as Istanbul, Ankara and Izmir, which cover approximately 30% of the population of Turkey, and (2) to develop some empirical models for these cities. Experimental data for lamir were measured in the SolarMeteorological Station of the Solar Energy Institute at Ege University. The present models were then compared with the 25 models, of which 12 were given in Part 1 of this study (defined as national models), while the remainder (called international models), presented here, and used for calculating H. The main percentage error (MPE), the root mean square error (RMSE), the main bias error (MBE) and the t-statistic (t-stat) methods were used for evaluating the performance of the models studied. It may be concluded that the present models predict the values of H for the three big cities better than other available models. [ABSTRACT FROM AUTHOR]

Most empirical models developed in the past to predict the performance of industrial screens are suitable specifically for vibratory screens. Understandably, these models are deficient in predicting the performance of linear screens due to the difference in their operating principles. The optimization of a Pansep linear screen has been successfully completed recently at the Southern Illinois University. Based on a significant amount of test data, empirical models have been developed to suitably predict the size separation performance from linear screens. The inadequacy of a vibratory screen model to predict the performance of a linear screen has been proved and a suitable model-fit has been suggested to predict the oversize partition coefficient as a function of the normalized mean particle size (d i /d 50c ) for a linear screen. In addition, an aperture-based model equation has been developed for linear screens to predict partition coefficient for a given size fraction as a function of only the screen aperture size. It is believed that this model equation will provide a simplistic tool to help plant operators in selecting the mesh panels of suitable aperture size and in predicting the product size distribution based on the selected aperture size and the size distribution of the feed materials. [ABSTRACT FROM AUTHOR]

A user-centred approach to human-computer interface design requires that the designer has appropriate tools to aid in the design process and employs iterative design procedures which incorporate user evaluations. The concept of using models of the user as an interface design tool is discussed, and several approaches to user modelling are described. These approaches are divided into the broad categories of conceptual and quantitative models. Conceptual models deal primarily with representations of users1 cognitive processes, structures and strategies. Quantitative models include performance, ergonomic, computer simulation and statistical models. Examples of both a conceptual and a quantitative model are provided to illustrate human-computer interface design implications. Some unresolved issues pertaining to both categories of models are discussed, and recommendations are made to improve modelling as an interface design tool. [ABSTRACT FROM PUBLISHER]