Lixia Hou

Northwest A & F University · College of Mechanical and Electronic Engineering

An unconventional and innovative mechanical transmission component, the Curved Groove Ball Bearing without Retainer (CGBBR), is introduced in this paper to facilitate the conversion between rotary and reciprocating motion. The CGBBR boasts several advantages over conventional motion conversion mechanisms, including a streamlined and compact structu...

To solve the problem of the lack of an accurate model for mechanized transportation and grading of walnut kernels, this paper took the shelled walnut kernels as the research object and calibrated the parameters of the discrete element model of walnut cracking kernels with the discrete element simulation software EDEM. The physical parameters of cra...

Radio frequency (RF) treatment is considered as an efficient and promising physical method for disinfesting and pasteurizing low-moisture agricultural products (LMAP) due to the rapid and volumetric heating. However, non-uniform RF heating is a major obstacle for industrial applications. A square container with ideal dielectric constant was develop...

Knowledge of the thermal and dielectric properties of wolfberries is essential for understanding the heat transfer and the interaction between the electromagnetic field (10–3000 MHz) and the sample during radio frequency (RF) and microwave (MW) drying. The thermal and dielectric properties of wolfberries were determined as influenced by moisture co...

Late blight caused by Phytophthora infestans is a destructive disease in potato production, which can lead to crop failure in severe cases. This study combined visible/near-infrared (Vis/NIR) spectroscopy with machine learning (ML) and chemometric methods for rapid detection of potato late blight. The determination of disease severity was accomplis...

Radio frequency (RF) treatment is a promising physical insecticidal technique in postharvest grains. The aim of this research was to discuss energy consumption and product quality using high-temperature-short-time RF treatments to completely eliminate Rhyzopertha dominica insect pests in coix seeds. A 6 kW, 27.12 MHz RF system was applied to conduc...

Radio frequency (RF) treatment is one of the most potential methods for disinfestations and pasteurizations of postharvest agriculture products. Non-uniform heating is the main issue for RF treatment to be used in a large-scale industrial application. A 6 kW, 27 MHz polit-scale RF system was used to reveal the heating uniformity of walnut kernels a...

A 3-D coupled electromagnetics, heat transfer, and mass transfer model for intermittent microwave drying of jujube fruit was developed to understand and optimize the effect of duty cycle (power level) and initial moisture on the temperature and moisture distributions and the rate of drying. The model was validated using measured temperature, pressu...

A major obstacle for industrial radio frequency (RF) treatments is non-uniform and thermal runaway heating. This study aimed to improve the RF heating uniformity in granular products using a rotation device with sample mixing. After the run-out error of the rotation device met the allowable tolerance range, the RF heating uniformity was evaluated f...

Four radio frequency (RF) heating systems with a power of 2 kW and four frequencies of 6.78, 13.56, 27.12, and 40.68 MHz were used to compare the effect of different frequencies on drying characteristics, disinfestation efficacy and product quality of in-shell walnuts. The results showed that with the increase of frequency, the average walnut tempe...

The comminuted meat products are popular and important in the global market. Radio frequency (RF) heating has been proposed as a new alternative method for thawing bulk frozen comminuted meat products with the main advantages of rapid and volumetric heating. However, the temperature non-uniformity is the main obstacle for its industrial application...

Thermal treatments are widely used to control bacterial fruit blotch on watermelon seeds contaminated by pathogens. It is necessary for developing effective heat treatments for seed pasteurization, which will not adversely affect their germination properties. The purpose of this study was to determine the effect of moisture content, temperature and...

Many disinfestation processes developed in pilot-scale radio frequency (RF) systems reveal that RF treatment is a promising non-chemical method to control insects in postharvest agricultural products. The purpose of this research was to determine efficiency of RF treatment for disinfesting rice in industrial applications. A free-running oscillator...

Thermal treatment has been extensively used to control pests in stored grains for a long time. The objective of this study was to analyze thermal death kinetics of adult flat grain beetle, Cryptolestes pusillus (Schonherr), lesser grain borer, Rhyzopertha dominica (Fabricius), and confused flour beetle, Tribolium confusum (Jacquelin du Val), using...

For simulating real pasteurization treatments using hot air, hot water, radio frequency and microwave heating, a unique experimental heating block system (HBS) was developed. The stability and uniformity of sample temperatures and heating rates in HBS were determined for studying the thermal resistance of food-borne pathogens. A computer simulation...

Infestations with fungi in chestnuts are one of the major safety issues during process and storage, resulting in short shelf-life and high economic losses. The purpose of this research was to study possible applications of radio frequency (RF) treatments for pasteurization of chestnuts to replace chemical methods. Thermal lethal kinetic models of f...

The efficacy of radio frequency (RF) treatment to inactivate Escherichia coli ATCC 25922 used as a surrogate of pathogenic Salmonella in almond kernels was investigated. A pilot-scale, 27 MHz, 6 kW RF unit was used to study the heating uniformity of almond kernels at the moisture content of 10.01% w.b. using two types of plastic containers. Pasteur...

Radio frequency (RF) heating has been successfully used for inactivating microorganisms in agricultural and food products. Athermal (non-thermal) effects of RF energy on microorganisms have been frequently proposed in the literature, resulting in difficulties for developing effective thermal treatment protocols. The purpose of this study was to ide...

A computer simulation model was developed using finite element-based commercial software, COMSOL, to simulate temperature distributions of single particle chestnuts packed in a rectangular plastic container and treated in a 6 kW, 27.12 MHz radio frequency (RF) system. The developed model was validated by temperature distributions of three horizonta...

Knowledge of bacteria’s heat resistance is essential for developing effective thermal treatments. Choosing an appropriate test method is important to accurately determine bacteria’s heat resistances. Although being a major factor to influence the thermo-tolerance of bacteria, the heating rate in samples cannot be controlled in water or oil bath met...

Radio frequency (RF) treatment is one of the most promising physical disinfestation methods in agricultural products due to rapid heating, deep penetration depth, and leaving no chemical residues. This paper focuses on reviewing uses of RF energy for disinfestation of agricultural products. It provides a brief introduction on the basic principle of...

Non-destructive quality detection and automatic grading are important in fruit industry. The traditional way divides bananas into 7-level ripening stages based on color. This study investigated the changes of peel color at three positions of banana fingers, i.e. stalk, middle and tip. A support vector machine method was used to classify the ripenin...

There has been an increased interest in developing alternative physical methods for disinfesting postharvest nuts under growing international pressures to replace chemical fumigation due to its adverse effects on human health and environment. The present research explored the possibility of using radio frequency (RF) heating as a non-chemical treat...

Thermal treatments are commonly used for disinfesting chestnuts before storage. Color is a first and sensitive quality attribute of chestnuts after thermal treatments and storage. The purpose of this study was to investigate L* and b* values in chestnuts during thermal treatment at 50-70°C for periods varying from 0 to 160 min, and during storage a...

Thermal death kinetics of Conogethes punctiferalis (Guenée) (Lepidoptera: Pyralidae) at different life stages, heating rate, and temperature is essential for developing postharvest treatments to control pests in chestnuts. Using a heating block system (HBS), the most heat-tolerant life stage of C. punctiferalis and the effects of heating rate (0.1,...

Chemical fumigation has been widely used to control insects in postharvest chestnuts but is inherent dangers when using fumigants. The purpose of this study was to validate application of radio frequency (RF) treatments for disinfesting chestnuts as an alternative to chemical fumigation. A practical process protocol was developed to control insect...

Methyl bromide fumigation, widely used for disinfesting chestnuts, will be banned in developing countries by 2015 under Montreal Protocol due to its adverse effects on human health and environment. The purpose of this research was to study possible applications of radio frequency (RF) heating for disinfestations of chestnuts to replace chemical fum...

Conventional hot air drying for pistachio nuts results in high energy consumption and low product quality. To develop advanced drying methods based on microwave (MW) and radio frequency (RF) energy, dielectric properties of pistachio kernel samples at different frequencies (10-4500 MHz), temperatures (25-85 A degrees C), moisture contents (3-27 % w...