Predicting the true density of commercial biomass pellets using near-infrared hyperspectral imaging

The use of biomass is increasing because it is a form of renewable energy that provides high heating value.Rapid measurements could be used to check the quality of biomass pellets during production.This research aims to apply a near-infrared(NIR)hyperspectral imaging system for the evaluation of the true density of individual biomass pellets during the production process.Real-time measurement of the true density could be beneficial for the operation settings,such as the ratio of the binding agent to the raw material,the temperature of operation,the production rate,and the mixing ratio.The true density could also be used for rough measurement of the bulk density,which is a necessary parameter in commercial production.Therefore,knowledge of the true density is required during production in order to maintain the pellet quality as well as operation conditions.A prediction model was developed using partial least squares(PLS)regression across different wavelengths selected using different spectral pre-treatment methods and variable selection methods.After model development,the performance of the models was compared.The best model for predicting the true density of individual pellets was developed with first-derivative spectra(D1)and variables selected by the genetic algorithm(GA)method,and the number of variables was reduced from 256 to 53 wavelengths.The model gave R_(cal)^(2),R_(val)^(2),SEC,SEP,and RPD values of 0.88,0.89,0.08 g/cm^(3),0.07 g/cm^(3),and 3.04,respectively.The optimal prediction model was applied to construct distribution maps of the true density of individual biomass pellets,with the level of the predicted values displayed in colour bars.This imaging technique could be used to check visually the true density of biomass pellets during the production process for warnings to quality control equipment.

Shaped Insulating Refractory Products——Determination of Bulk Density and True Porosity

1 Scope This standard specifies a method for the determination of the bulk density and true porosity of shaped insulating refractory products.

Microwave drying kinetics and quality characteristics of corn

In recent years,microwave(MW)drying has gained popularity as an alternative drying method for a wide variety of food and agricultural products because of increasing concerns over product quality and production costs.However,the determination of drying kinetics that accurately describes microwave drying characteristics is crucial for the optimization of operating parameters,performance improvement of the drying system and product quality.The objective of this study was to investigate the drying kinetics and the quality characteristics of corn kernels,especially the effects of different initial moisture contents(18.3%,26.3%,34.3%and 42.3%db),MW power levels(70,175 and 245 W)and exposure time(80 s and 120 s)on the drying kinetics,drying rate and various key quality parameters.The results indicated that the increased drying rate at higher power levels(P3,245 W)reduced the drying time considerably but increased stress crack index and reduced germination.In addition,it reduced bulk density,true density and thousand grain weight(TGW).The germination rate of corn was the highest at MW power level P1(70 W),with the lowest drying rate and observed to decrease with increase in initial moisture content.The reduction in exposure time decreased stress crack index and increased germination rate,bulk density and true density.The correlation analysis among drying rate,germination,stress-crack index(SCI),bulk density,true density and TGW showed that increasing drying rate could lead to an increase in SCI and decrease in germination,bulk density and true density.

Some physical properties of Australian Nonpareil almonds related to bulk storage

The Australian almond industry desires to improve storage of harvested almonds awaiting processing.The present work quantified some storage-related physical properties of almonds.The sample used in the study was Nonpareil almonds with a kernel moisture content of 4.5% d.b.The mass composition of the sample was 55% hull,32% kernel and 13% shell.Tests showed that the bulk stored in-shell almonds had only 41% of the volume of in-hull almonds and 45% of the mass.Thus removing hulls before storage would result in saving both storage and subsequent transportation costs.Tests simulating various storage heights of almonds showed that a 10 m storage height of almonds increased the bulk density of in-hull almonds from 320 to 355 kg/m^(3),of in-shell almonds(hull removed)from 356 to 378 kg/m3,and kernels(hull and shell removed)from 604 to 649 kg/m^(3).A 10 m storage height of almonds reduced the porosity of in-hull almonds from 67% to 64%,of in-shell almonds from 58% to 55%,and of the kernel from 48% to 44%.Observation showed that the change in bulk density and porosity occurred in an exponential manner with fitted curves that provided R2 between 0.97 and 0.99.