A mechanical model for felt in impulse drying: A cellular materials approach. II. Experimental validation

High-intensity paper drying processes involve the complex phenomena of multiphase transport in porous media. Impulse drying is such a process, in which enhanced liquid water removal is the key to energy savings. This paper concerns the study of the mechanical behavior of felts used in the papermaking industry, namely those applied in the press section of the paper machine. Here, a viscoelastoplastic model based on the cellular solids theory is presented, and its range of adequacy explored using data from uniaxial laboratory experiments. The model predictions show some agreement with the experiments but accurate documentation of multiphase-flow parameters and a proper heat and mass transport model, able to describe the multiphase transport in the course of the pressing event, would certainly improve the performance of the model.     

Quality control of card web uniformity for a vertical-type cross-lapper machine. I. Dynamic system modeling and industrial controller design

This series of paper addressed the quality control of a vertical-type cross-lapper machine, which is used to produce uniform layers of fibers with suitable widths and thicknesses. The nonlinear model of the system was derived, and the corresponding state space representation was obtained. The linearized model based on the equilibrium position of the nonlinear model was generated, and the associated control property was analyzed. The high order linearized model would be reduced to a verified lower order model for control system design. The designed traditional and modern controller could make the crosslapper machine for good card web quality control.     

A study of comfort performance in cotton and polyester blended fabrics. I. Vertical wicking behavior

Vertical wicking model was developed based on Darcy’s law. In the model, permeability coefficient, capillary pressure and fabric thickness were used as the key parameters to describe wicking behavior. For the simulation and test, fiber type and fabric structure were chosen as variables. In a highly porous knit fabric, gravitational effect during the wicking process was significant. The higher the capillary pressure was, the higher was the wicking rise. Surface wetting tension, i.e., the specific fluid affinity of material, was newly defined to characterize different capillary pressures in various types of fabric structures. The model, the methodology and the results could provide an insight into fabric design to produce fabric with an optimum wicking performance.     

A simulation model of cereal–legume intercropping systems for semi-arid regions: I. Model development

Cereal–legume intercropping plays an important role in subsistence food production in developing countries, especially in situations of limited water resources. Crop simulation can be used to assess risk for intercrop productivity over time and space. In this study, a simple model for intercropping was developed for cereal and legume growth and yield, under semi-arid conditions. The model is based on radiation interception and use, and incorporates a water stress factor. Total dry matter and yield are functions of photosynthetically active radiation (PAR), the fraction of radiation intercepted and radiation use efficiency (RUE). One of two PAR sub-models was used to estimate PAR from solar radiation; either PAR is 50% of solar radiation or the ratio of PAR to solar radiation (PAR/SR) is a function of the clearness index (K_T). The fraction of radiation intercepted was calculated either based on Beer's Law with crop extinction coefficients (K) from field experiments or from previous reports. RUE was calculated as a function of available soil water to a depth of 900 mm (ASW). Either the soil water balance method or the decay curve approach was used to determine ASW. Thus, two alternatives for each of three factors, i.e., PAR/SR, K and ASW, were considered, giving eight possible models (2 methods × 3 factors). The model calibration and validation were carried out with maize–bean intercropping systems using data collected in a semi-arid region (Bloemfontein, Free State, South Africa) during seven growing seasons (1996/1997–2002/2003). The combination of PAR estimated from the clearness index, a crop extinction coefficient from the field experiment and the decay curve model gave the most reasonable and acceptable result. The intercrop model developed in this study is simple, so this modelling approach can be employed to develop other cereal–legume intercrop models for semi-arid regions.     

Grass silage for biorefinery—A meta‐analysis of silage factors affecting liquid–solid separation

This meta‐analysis based on 19 studies from Finland comprising 43 grass silages was undertaken to evaluate the effect of silage quality on liquid yield, liquid composition and retained compounds in liquid using four different liquid–solid separation methods. Silages were classified according to species (grass, clover or a mixture of them), additive treatment (no, biological or formic acid‐based additive) and harvest (primary growth or regrowth). A mixed model regression analysis with random study effect was used to evaluate the impact of silage characteristics on biorefinery efficiency. There was a large variation in silage quality in the data set. Silage dry‐matter concentration was the characteristic most highly correlated with liquid yield for all separation methods, and when used as an independent variable in the model, it resulted in the best predictions. The liquid–solid separation methods presented a great variation in the liquid yield, ranging from 0.26 to 0.56 when silage dry‐matter concentration was standardized to 250 g/kg. There was no effect of additive treatment and harvest in the estimation of the biorefinery potential, but species was a significant variable in predicting liquid yield for the laboratory‐scale presses with higher liquid yield for mixed grass and legume. The high correlation between silage quality and liquid yield and liquid composition provides potential to predict the biorefinery potential based on equations developed for each separation method. This information can be used to modify the silage production systems so that they best meet the requirements of a green biorefinery process.     

GrazeIn: a model of herbage intake and milk production for grazing dairy cows. 2. Prediction of intake under rotational and continuously stocked grazing management

Decision support tools to help dairy farmers gain confidence in grazing management need to be able to predict performance of grazing animals with easy‐to‐obtain variables on farm. This paper, the second of a series of three, describes the GrazeIn model predicting herbage intake for grazing dairy cows. The model of voluntary intake described in the first paper is adapted to grazing situations taking account of sward characteristics and grazing management, which can potentially affect intake compared to indoor feeding. Rotational and continuously stocked grazing systems are considered separately. Specific effects of grazing management on intake were quantified from an extensive literature review, including the effect of daily herbage allowance and pre‐grazing herbage mass in rotational grazing systems, sward surface height in continuously stocked grazing systems, and daily time at pasture in both grazing systems. The model, based on iterative procedures, estimates many interactions between cows, supplements, sward characteristics and grazing management. The sensitivity of the prediction of herbage intake to sward and management characteristics, as well as the robustness of the simulations and an external validation of the GrazeIn model with an independent data set, is presented in a third paper.     

A Bayesian approach to assess the accuracy of a diagnostic test based on plant disease measurement

The proportion of diseased plant organs measured before chemical treatment is often used to make an assessment of the need for crop protection in agricultural plots, but such diagnostic tests are not perfect and sometimes lead to incorrect decisions. The area under the receiver operating characteristic (ROC) curve is a popular index of the overall performance of a test. It can be interpreted as the probability that the test value for a randomly chosen diseased subject will exceed that of a randomly chosen disease-free subject. In this paper, we present a Gaussian/Binomial model to assess the accuracy of diagnostic test based on a measured proportion of diseased plant organs. The model parameters were estimated from a real dataset and the model was used to analyse the accuracy of a diagnostic test based on a measured proportion of oilseed rape flowers contaminated by Sclerotinia sclerotiorum. The results showed that the accuracy of the test depends on the number of collected flowers, but that it is not necessary to collect more than 40 flowers per plot. A simulation study showed that the bias of the estimator of the area under the ROC curve was near zero for all size of dataset and that its mean-square error decreased in function of the number of experimental plots used in the ROC analysis. A major interest of our approach is that it allows one to study the effect of the sample size of the organs on the accuracy of the test. It can also be used to estimate the probability of disease occurrence, and to determine a decision threshold according to the sensitivity and specificity values.     

A combined technique of floodplain storage and reservoir irrigation for paddy rice cultivation

This paper introduces an irrigation system developed in the floodplain of a lake and studies the water management technique of the irrigation system by estimating the total water balance of the whole system. The system is characterized by a reservoir combined with a dike system in the floodplain of the Tonle Sap Great Lake and an irrigation system. Two main models are used for calculating the total water balance. The first model is the water balance of the reservoir. The inputs to the model are water level of the reservoir, precipitation, lake evaporation, infiltration, and area–volume curve of the reservoir. The outputs are inflow and outflow of the reservoir. The supply from the reservoir to paddy fields is computed from the outflow. The second model is the water balance of paddy fields, based on which the water requirement in paddy fields is derived. The reference evapotranspiration needed to calculate the water requirement is simulated for monthly time series using the FAO Penman–Monteith model. Since there is no drainage network in the irrigation system, surface drainage and runoff are not included in the calculation of the water balance, and seepage is considered negligible in the flat floodplain area. The evapotranspiration, rice variety, soil type and irrigated area are used to simulate water consumption in paddy fields. Finally, the two models are connected to produce the total water balance from the reservoir to paddy fields. The total outflow from the reservoir is estimated and the total water consumption for dry season cultivation is also determined. Finally, the efficiency of the whole system is examined.     

A modified grey verhulst model method to predict ultraviolet protection performance of aging B.mori silk fabric

In this paper, an improved grey model by using Fourier series of error residuals to predict the tendency of ultraviolet protection performance of aging B.mori silk fabric is proposed. The ultraviolet protection factor of B.mori silk fabric under natural weathering was used as the test data set. In addition, the relative percentage error (RPE), the average relative percentage error (ARPE) and the root mean square error (RMSE) were used to compare the performance of the forecast models. The results showed that the improved EFGVM(1,1) model is more accurate and performs better than the traditional GM(1,1) model and grey Verhulst model.     

油菜发育过程及生育期机理模型的研究Ⅱ.模型的检验和评价

利用国内3组不同年份、不同品种、不同播期、不同施肥处理的田间试验资料,对第Ⅰ报中所描述的油菜发育过程及生育期模型进行了验证.结果表明,模型对大多数生育阶段的模拟误差为3d左右,平均差平方和的根值(root mean square error,RMSE)也为3d左右,尤其对初花期、终花期、成熟期的模拟精度高、误差小.模型表现出较强的机理性以及较好的预测性和实用性.     

GrazeIn: a model of herbage intake and milk production for grazing dairy cows. 1. Prediction of intake capacity,voluntary intake and milk production during lactation

The prediction of both food intake and milk production constitutes a major issue in ruminants. This article presents a model predicting voluntary dry matter intake and milk production by lactating cows fed indoors. This model, with an extension to predict herbage intake at grazing presented in a second article, is used in the Grazemore decision support system. The model is largely based on the INRA fill unit system, consisting of predicting separately the intake capacity of the cows and the fill value (ingestibility) of each feed. The intake capacity model considers potential milk production as a key component of voluntary feed intake. This potential milk production represents the energy requirement of the mammary gland, adjusted by protein supply when the protein availability is limiting. Actual milk production is predicted from the potential milk production and from the nutritional status of the cow. The law of response of milk production is a function of the difference between energy demand and actual energy intake, modulated by protein intake level. The simulation of experimental data from different feeding trials illustrates the performance of the model. This new model enables dynamic simulations of intake and milk production sensitive to feeding management during the whole lactation period.     

向日葵菌核病消长动态分析模型

向日葵菌核病是内蒙古自治区向日葵生产上的一个严重病害,其流行有突增突降的特点。本文探索了向日葵种植面积与病因产量、菌核生成量之间关系。在此基础上应用突变(Catastrophe)理论对向日葵菌核病的消长动态作了分析,并给出了一个说明菌核突增、突降动态及原因的分析模型的实例。     

Optimising harvest date in sugar production: A case study for the Mossman mill region in Australia: I. Development of operations research model and solution

Cane and sugar yields within a sugar mill region can vary with geographical location, harvest date, harvest age, variety and crop class. It is not possible, due to limited mill capacity, to harvest all cane when maximum yields are attained. Given a prolonged harvest season, an important question is how the harvest of individual paddocks of cane should be scheduled so as to maximise net revenue for the entire mill region. This paper presents the application of an optimisation model to the Mossman mill region with the objectives of maximising sugar yield and net revenue in relation to harvest date and crop age. Six years of block productivity data classified according to district, crop class, variety, harvest date, harvest age, cane yield and sugar yield, were used to generate the input parameters for the model. Other inputs were sugar price, growing and milling costs, and transport and crushing capacity. With current crushing capacity and harvest season lengths, an application of the model to maximise sugar yield showed a 4% increase in sugar yield compared to current practice, but a 23% decrease in net revenue due to a shorter crop cycle with less ratoons before replanting. Optimising with respect to net revenue, gave a 3% gain in sugar yield with an 8% gain in net revenue. When crushing capacity was allowed to increase for current season lengths, the model showed a 14% gain in net revenue given fixed milling costs. It is concluded that there is scope for optimising harvest date to improve profitability in this mill region given current harvest season lengths and land area.     

国营农场经济效益综合评估模式

衡量国营农场经济效益的诸项指标之间并非是相互独立、同步变化的,而是相互联系和相互制约着的。这给评估国营农场的经济效益带来困难。本文给出了一个评判国营农场经济效益的综合评估模式,并将此模式制成计算机软件。     

A mathematical model of the aerobic deterioration of silage

A mathematical model of the aerobic deterioration of silage is described that includes the physical processes of gas and heat Rows, as well as an established model of microbial growth and the associated chemical changes. Yeasts and acetic acid bacteria are included in the growth model. The version of the model described relates to a cylinder of silage subject to forced aeration, a common experimental configuration. The model was very sensitive to variations in insulation thickness and yeast growth rate, and to initial pH, especially when maize was the forage. Great care is needed when selecting input data for use in the model to be sure that the physical and chemical properties are accurate. The model solution was sensitive to grid size, but with 361 cells, the maximum grid resolution that could be used on a 486 series PC, solutions were achieved with an acceptably small loss of accuracy. The model predicted the results of an experiment on silage deterioration quite accurately. However, the model also predicted that considerable spatial gradients of parameters, such as temperature, pH, and lactic acid, would occur. This indicates the need for care when taking samples or making temperature measurements in deterioration experiments. The model is potentially a useful tool in predicting the optimal time and position to take samples for analysis in a time-course experiment.     

Calculation of bed load based on the measured data of suspended load

This paper proposes a method for establishing both the velocity profile and concentration profile for suspended sediment based on measured data consisting of average velocity and average suspended sediment concentration in the river and the irrigation channel. In addition, a numerical model for computing suspended load and bed load was also developed for computing bed load transport rate when measurable load is available. In this study, bed loads for published laboratory and field sediment data were computed using the presently developed numerical model based on four different bed layer thicknesses. The computed bed loads were found to be in reasonable agreement with the values from Einstein’s bed load function when the thickness of the bed layer was taken at 10θd or 0.05D. The numerical model developed in this study may be used to evaluate the validities of other bed load formulas.     

花生氮磷钾肥料效应函数模型的研究

本试验是采用最优设计进行的N、P、K三因素肥料试验,试验结果获得了三个因素与产量间相互关系的函数模型。本文分析了三个因素的产量效应及其交互作用,分别计算出最高产量、最大施肥利润以及不同产量水平最低成本的施肥量及其配比,为合理施肥提供依据。     

Wire frame representation of 3D moulded bra cup and its application to example-based design

Fabric or foam sheet moulding is an important manufacturing technique for the apparel industry, in particular for bra production. It is the most economical and convenient method to seamlessly form a garment part into a specified 3D shape. This paper proposes an example-based method for designing moulded bra cups. In this study, a total of 10 typical moulded bra cup specimens were scanned using the Steinbichler Comet white light scanner. Parameterization based remeshing and registration algorithm was used to characterize the 3D shapes of the convex surface of the scanned bra cups. Using an example-based method, virtual master moulds were constructed based on the 3D surfaces of the investigated bra cups after eliminating the style lines and size differences. Then a new bra cup design can be developed from the master mould, either by drawing the style lines in the virtual environment or using scissors to cut the moulded plastic shot along the desired style lines. Different sizes can also be made by grading the wire frame model in 3D manner. The present method will provide a scientific tool for the product development of new bra cups which was conventionally very time-consuming and ineffective.     

斜纹夜蛾幼虫存活过程的神经网络模型的建立

利用BP神经网络对斜纹夜蛾幼虫的存活过程进行建模分析,给出了BP神经网络建模的Matlab算法程序。结果表明,BP神经网络能充分逼近斜纹夜蛾幼虫的存活过程曲线,使用BP神经网络可对斜纹夜蛾幼虫的存活过程进行有效的建模。利用所建立的模型,得到了关于斜纹夜蛾幼虫存活过程的模拟预测结果。不同温度下斜纹夜蛾幼虫种群的死亡过程有所不同。在20,24,36和40℃温度下,斜纹夜蛾幼虫种群的死亡高峰分别出现在卵孵化后20d左右,5～20d,5～10d及3～6d。最后,对神经网络建模的特点,以及影响BP神经网络建模效果的主要因素进行了分析讨论。     

Evaluation of malting barley quality using exploratory data analysis. II. The use of kernel hardness and image analysis as screening methods

This paper presents an exploratory investigation of the use of image analysis and hardness analysis of barley kernels for characterisation and prediction of malting quality. A sample set of fifty barley samples representing 15 spring barley and 10 winter barley varieties grown at two locations in Denmark was used. The samples were micro-malted and mashed and analysed for 13 quality parameters according to the official methods of the European Brewery Convention. A sub-sample of the barley samples was analysed on two different single kernel instruments: (1) Foss Tecator GrainCheck was applied for non-destructive recording of single kernel size and shape (width, length, roundness, area, volume and total light reflectance) and (2) Perten Single Kernel Characterization System 4100 was applied for single kernel hardness and weight determinations. The eight variables from these single seed analyses have been used in two different ways, either as means and standard deviations, or as appended histogram spectra representing 250 kernels from each bulk sample. By the two methods, it has been possible to obtain reasonable Partial Least Squares Regression (PLSR) models for the structural and physical part of the malting quality complex associated to malt modification, but it was as expected impossible to predict the biochemical parameters associated with nitrogen chemistry and enzymatic power. The best model was achieved for (1→3, 1→4)-β-D-glucan in barley. The hardness of the barley kernels is by far the most important variable for describing malting performance. The additional use of the morphological data as acquired by fast non-destructive image analysis, however, also reveals some malting quality information by improving the calibration models based on hardness alone. The brightness of the kernels is by far the most important GrainCheck variable but also kernel size and shape is associated to malting performance. In general, the utilisation of the single kernel readings (used as histogram spectra), compared to sample mean and standard deviation, did not provide additional information for an improved prediction of the malting quality parameters.