Performance evaluation of a flatbed maize dryer with a biomass heat source

The technical performance of a 3-tonne capacity flatbed grain dryer was assessed based on its drying rate and drying efficiency. In addition, the quality of maize grains dried in the drying system was investigated through stress-crack analysis and germination test. Maize grains at an initial moisture content of 18.4% ± 0.1% (wb) were dried to a safe moisture content of 13.3% ± 0.2% (wb) in 5 hours, resulting in a drying rate of 1.02%/h at a drying efficiency of 67.35%. The average temperature observed in the plenum (55.8°C±1.5°C) was about twice higher than the ambient temperature during the drying period. The use of the flatbed dryer did not have any adverse effect on the viability of grains dried with a stress-crack index of 75 and percentage germination of 90%. This study demonstrated the viability of using the flatbed biomass-assisted dryer for drying maize and can reduce post-harvest losses of maize at the smallholder level. Int. J. Agril. Res. Innov. Tech. 11(2): 37-41, Dec 2021

LIMBAH KAYU DAN KERTAS BEKAS UNTUK PULP KERTAS

His study aims to analyze the extent to which a mixture of wood waste and used newsprint can be used as raw material for making paper.This study used a completely randomized design with two replications. where the treatment given is a mixture composition between waste wood pulp and old newsprint pulp, each consisting of 0 : 100% (A), 30% 70% (B), 50% : 50% (C), 70% : 30% (D) and 100% : 0% (E) of oven-dry weight of pulp per sheet of paperThe physical properties of paper pulp tested in the form of tear index, tensile index, crack index and folding resistance significantly affect the composition of the mixture of wood waste and used newsprint.The value of tear index, tensile index and folding resistance tend to decrease with the increase in the percentage of used newsprint to the composition of the mixture, while the value of the crack index increases. Wood waste and used newsprint can be used as raw materials in pulp and paper manufacture, especially in the treatment of mixed composition C (50%:50%.)

Pavement Crack Detection from Hyperspectral Images Using a Novel Asphalt Crack Index

Detection of road pavement cracks is important and needed at an early stage to repair the road and extend its lifetime for maintaining city roads. Cracks are hard to detect from images taken with visible spectrum cameras due to noise and ambiguity with background textures besides the lack of distinct features in cracks. Hyperspectral images are sensitive to surface material changes and their potential for road crack detection is explored here. The key observation is that road cracks reveal the interior material that is different from the worn surface material. A novel asphalt crack index is introduced here as an additional clue that is sensitive to the spectra in the range 450–550 nm. The crack index is computed and found to be strongly correlated with the appearance of fresh asphalt cracks. The new index is then used to differentiate cracks from road surfaces. Several experiments have been made, which confirmed that the proposed index is effective for crack detection. The recall-precision analysis showed an increase in the associated F1-score by an average of 21.37% compared to the VIS2 metric in the literature (a metric used to classify pavement condition from hyperspectral data).

Analytical Model for Air Flow into Cracked Concrete Structures for Super-Speed Tube Transport Systems

The super-speed tube transport (SSTT) system, which enables high-speed transportation in a partially vacuumed tube by minimizing the air resistance, is drawing attention as a next-generation transportation system. To evaluate the applicability of concrete as a material for the system, the effect of cracks on the airtightness of the system needs to be considered. This study aims to establish an analytical relationship between the cracks induced on a concrete tube structure and the system airtightness. An analytical model for the leakage rate through the concrete cracks is first applied to establish a differential equation, which can help determine the air flow rate into the concrete tube structure through the cracks. A mathematical formula for predicting the internal pressure changes over time in the concrete tube structure is then derived. The effect of crack development on the system airtightness is assessed through parametric analysis and a crack index for describing the extent of crack development is proposed by investigating the correlation with the system airtightness. Finally, assuming that the cracks due to external loadings are closely related to the displacement, the correlation between displacements and the airtightness of concrete tube structures is demonstrated through a set of experimental tests. As a result, the necessity of crack analysis for evaluation of the airtightness performance is emphasized.

Study on the Correlation of Vibration Properties and Crack Index in the Health Assessment of Tunnel Lining

This paper examines the correlation of vibration properties and crack index of tunnel lining in evaluating risk of collapsing. The visual inspection method, which was widely used, was not reliable enough as the stability of tunnel lining was influenced by the voids and the cracks that were invisible. A new method for the health assessment of tunnel lining was proposed, which can evaluate the whole structural condition according to the vibration properties of tunnel lining. A series of field tests were conducted to evaluate the validity of this new method and to make a comparative analysis with the visual inspection test results. The resultant average spectrum (RAS) of tunnel lining was identified according to the acceleration data of ambient vibration test of Hidake Tunnel in Japan. The tunnel lining crack index (TCI) was also obtained by digital visual inspection test. The correlation between the vibration characteristics and the crack index of tunnel lining was confirmed. However, the voids and the cracks on the inside of the lining were neglected in visual inspection test, which could pose a serious threat to tunnel safety. The vibration measurements by seismometer are an effective way to evaluate the global stability of tunnel lining.