Background Quality of pre-processed food grains is a critical aspect and a major decider of market acceptability, storage stability, processing quality, and overall consumer acceptance. Among various indices of food grain quality evaluation, physical appearance (including external morphology) provides the foremost assessment on the condition of the grain. Conventional method of grain quality evaluation, visual inspection (a manual method) is challenging even for trained personnel in terms of rapidity, reliability and accuracy. Scope and approach Machine vision systems have the potential to replace manual (visual) methods of inspection and, have therefore gained wide acceptance in industries as a tool for quality evaluation of numerous agricultural products. This note provides an up-to-date review on the major applications of machine vision systems for grain quality evaluation applications in non-touching arrangement, highlighting system components, image processing and image analysis techniques, advantages and limitations of machine vision systems. Key findings and conclusions Machine vision systems can provide rapid and accurate information about external quality aspects of food grains. However, it is a task to integrate such systems with those that can explain internal grain quality attributes. In the near future, with ever-growing application requirements and research developments, machine vision systems can provide effective solutions for various grain quality evaluation applications.

Machine vision system for food grain quality evaluation: A review

Managing water on heat transfer surfaces: A critical review of techniques to modify surface wettability for applications with condensation or evaporation

This paper concerns the design, fabrication and characterization of graphite/PDMS sensors for low-force sensing applications. Exploiting the design flexibility of 3D printing, moulds of specific dimensions were prepared onto which graphite powder and PDMS were cast, to develop sensor patches. The sensor patches were highly flexible with repeatable responses to iterative bending cycles. The patches were tested in terms of stretchability, strain and bending-cycle responses. The sensor patches had interdigitated electrodes operating on capacitive sensing, where the effective capacitance changes with an applied force because of changes in their dimensions. Forces ranging from 3.5 mN to 17.5 mN were applied to determine the capability of these sensor patches for low-force sensing applications. The sensor patches had a quick recovery having a sensitivity and SNR per unit force of 0.2542 pF mN−1 and 10.86 respectively. The patches were capable of differentiating the forces applied on them, when they were attached to different objects in daily use.

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3D printed mould-based graphite/PDMS sensor for low-force applications

Fuel cells are the most clean and efficient power source for vehicles. In particular, proton exchange membrane fuel cells (PEMFCs) are the most promising candidate for automobile applications due to their rapid start-up and low-temperature operation. Through extensive global research efforts in the latest decade, the performance of PEMFCs, including energy efficiency, volumetric and mass power density, and low temperature startup ability, have achieved significant breakthroughs. In 2014, fuel cell powered vehicles were introduced into the market by several prominent vehicle companies. However, the low durability and high cost of PEMFC systems are still the main obstacles for large-scale industrialization of this technology. The key materials and components used in PEMFCs greatly affect their durability and cost. In this review, the technical progress of key materials and components for PEMFCs has been summarized and critically discussed, including topics such as the membrane, catalyst layer, gas diffusion layer, and bipolar plate. The development of high-durability processing technologies is also introduced. Finally, this review is concluded with personal perspectives on the future research directions of this area.

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Recent Progress on the Key Materials and Components for Proton Exchange Membrane Fuel Cells in Vehicle Applications

Micropatterned polymer surfaces, possessing both topographical and chemical characteristics, were prepared on three-dimensional copper tubes and used to capture atmospheric water. The micropatterns mimic the structure on the back of a desert beetle that condenses water from the air in a very dry environment. The patterned coatings were prepared by the dewetting of thin films of poly-4-vinylpyridine (P4VP) on top of polystyrene films (PS) films, upon solvent annealing, and consist of raised hydrophilic bumps on a hydrophobic background. The size and density distribution of the hydrophilic bumps could be tuned widely by adjusting the initial thickness of the P4VP films: the diameter of the produced bumps and their height could be varied by almost 2 orders of magnitude (1–80 μm and 40–9000 nm, respectively), and their distribution density could be varied by 5 orders of magnitude. Under low subcooling conditions (3 °C), the highest rate of water condensation was measured on the largest (80 μm diameter) hydrop...

Patterned Polymer Coatings Increase the Efficiency of Dew Harvesting.

We present a continuous fabrication method to make bio-inspired water collecting surface by using roll type photolithography for potential applications to real time air monitoring system. In this study, the carapace of the stenocara beetle was mimicked to achieve water collection from air, using a molding process involving micro-/nanofabrication techniques and roll type photolithography. We fabricated a super-hydrophilic surface on top of a super-hydrophobic surface and used two different setups to demonstrate water collection, a thermoelectric module and a humidifier. Also, the optimized geometric design for water collection was found from 16 different test samples. Detection of mercury is shown as a feasible practical application of such surfaces.

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Continuous fabrication of bio-inspired water collecting surface via roll-type photolithography

In this paper, a digital image analysis method was developed to classify seven kinds of individual grain kernels (common rice, glutinous rice, rough rice, brown rice, buckwheat, common barley and glutinous barley) widely planted in Korea A total of 2800 color images of individual grain kernels were acquired as a data set Seven color and ten morphological features were extracted and processed by linear discriminant analysis to improve the efficiency of the identification process The output features from linear discriminant analysis were used as input to the four-layer back-propagation network to classify different grain kernel varieties The data set was divided into three groups: 70% for training, 20% for validation, and 10% for testing the network The classification experimental results show that the proposed method is able to classify the grain kernel varieties efficiently

https://iopscience.iop.org/article/10.1088/0957-0233/22/6/064006/pdf

Intelligent classification methods of grain kernels using computer vision analysis

The gas diffusion layer (GDL) is an important component of proton-exchange membrane fuel cells (PEMFCs) that participate in the interplay of the transport of different species. During the assembly of PEMFCs, mechanical pressure is applied to the solid boundary of bipolar plates to reduce the porosity of the adjacent GDL, especially under land areas. This variation in porosity reduces reactant consumption in the catalyst layer and primarily causes non-uniform current density in PEMFCs. To compensate for the loss of porosity in the GDL, a composite porous diffusion layer was used as a GDL with higher porosity in the under-land areas of the GDL than that in the under-channel areas. A numerical simulation was conducted to investigate the effect of the positional variation of porosity on the performance of the PEMFC. The overall performance of the cell was investigated through a polarization plot, and the local mass transport of the reactant species was evaluated at the two reaction sites. The introduction of the proposed composite porous GDL improved the performance of the PEMFC by enhancing the transport of the reactant species to and from the reaction site.

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Effects of composite porous gas-diffusion layers on performance of proton exchange membrane fuel cell

Characteristics of Blood Vessel Wall Deformation with Porous Wall Conditions in an Aortic Arch

An integrated algorithm that combines Dynamic Adaptive Backstepping (DAB), Sliding Mode Control (SMC), and a saturated proportional integral function (PI) is presented for the control of non-triangular nonlinear systems with unmatched uncertainties. Adaptive Backstepping is a recursive design methodology that uses of virtual functions as well as tuning functions, while sliding mode control is used to obtain more robustness towards disturbances and unmodeled dynamics. The main advantages of the PI function are the complete removal of chattering, a shorter transient period, and higher accuracy. A comparison of Dynamic Adaptive Backstepping Sliding Mode Control (DAB-SMC) and Dynamic Adaptive Backstepping Saturated Proportional Integral Sliding Mode Control (DAB-PISMC) is presented to show the effectiveness of the proposed algorithm

Choon Young Lee

Papers

Continuous fabrication of bio-inspired water collecting surface via roll-type photolithography

Intelligent classification methods of grain kernels using computer vision analysis

Effects of composite porous gas-diffusion layers on performance of proton exchange membrane fuel cell

Characteristics of Blood Vessel Wall Deformation with Porous Wall Conditions in an Aortic Arch

Dynamic adaptive backstepping and saturated proportional integral sliding mode control for uncertain nonlinear systems