نتایج جستجو برای: free microwave extraction

تعداد نتایج: 718880  

2012
Irena Zivkovic Axel Murk

In this work we will present new method, retrieved results and validation for complex and frequency dependent permittivity and permeability parameter extraction of two composite, homogeneous and isotropic magnetically loaded microwave absorbers (CR Eccosorb). Permittivity and permeability are extracted from free space transmission measurements for frequencies up to 140GHz. For the results valid...

Journal: :Horticulturae 2022

The extraction of bioactive plant components, which belong to specialized metabolites, is carried out by conventional and novel methods. In this study, a classical (hydrodistillation, HD) technique (microwave-assisted water extraction, MAE) were used isolate free volatile compounds from nine Croatian Veronica taxa (family Plantaginaceae). Each these extracts consists lipophilic phase an aqueous...

Journal: :Journal of chromatography. A 2008
Jun-Xia Wang Xiao-Hua Xiao Gong-Ke Li

Vacuum microwave-assisted extraction (VMAE), in which microwave-assisted extraction (MAE) was performed in vacuum, was specially designed and applied for the extraction of polyphenolic compounds and pigments from Chinese herbs. The extraction conditions including solid/liquid ratio, extraction time, extraction temperature and degree of vacuum were optimized. Subsequently, VMAE, MAE, and convent...

2011
I. Zivkovic A. Murk

This work presents new method, retrieved results and validation for complex and frequency dependent permittivity and permeability parameter extraction of two composite, homogeneous and isotropic magnetically loaded microwave absorbers. Permittivities and permeabilities are extracted from free space transmission measurements for frequencies from 22 up to 140 GHz. For validation of the results re...

2012
Chunhui Ma Lei Yang Wenjie Wang Fengjian Yang Chunjian Zhao Yuangang Zu

An ultrasound and microwave assisted alternant extraction method (UMAE) was applied for extracting dihydroquercetin (DHQ) from Larix gmelinii wood. This investigation was conducted using 60% ethanol as solvent, 1:12 solid to liquid ratio, and 3 h soaking time. The optimum treatment time was ultrasound 40 min, microwave 20 min, respectively, and the extraction was performed once. Under the optim...

2017
Fernanda Carolina Sousa Fonseca Letícia Caribé Batista Reis Jener David Gonçalves dos Santos Carla Rodrigues Cardoso Branco Sergio Luis da Costa Ferreira Jorge Mauricio David Alexsandro Branco

BACKGROUND The effect of the extraction time (min) and temperature (°C) on the yield of betulinic acid (BA) from Zizyphus joazeiro barks using focused microwave-assisted extraction was investigated. MATERIALS AND METHODS The ethyl acetate was used as extractor solvent because it was shown to provide a betulinic acid-clean extract. A full two-level statistical factorial design was applied to d...

Journal: :International Journal of Renewable Energy Development 2021

The aim of this study is to evaluate microwave-assisted extraction at several microwave power and time in extracting oil palm products, such as crude (CPO) fatty acid (PFA) composition. exposure was shortened overheating avoided when sterilized mesocarp exposed prior Soxhlet order obtain good quality oil. effects CPO PFA composition on the distillate produced were investigated. Gas chromatograp...

Journal: :Journal of analytical toxicology 2007
Purificación Fernández Marta Lago Rosa Antonia Lorenzo Antonia María Carro Ana María Bermejo María Jesús Tabernero

A sample preparation procedure using microwave energy is proposed for the determination of morphine, 6-acetylmorphine, codeine, cocaine, cocaethylene, benzoylecgonine, methadone, and 2-ethylene-1,5-dimethyl-3,3-diphenylpyrrolidine in human plasma. A screening asymmetrical factorial design was used to identify the most suitable extraction conditions as regards solvent, temperature, and extractio...

2017
Ali Ghasemzadeh Hawa Z E Jaafar Asmah Rahmat Mallappa Kumara Swamy

BACKGROUND The extraction of bioactive compounds from herbal materials requires optimization in order to recover the highest active dose. Response surface methodology was used to optimize variables affecting the microwave extraction of zerumbone from Zingiber zerumbet using the Box-Behnken design. The influence of variables, such as ethanol concentration (X1), microwave power (X2), irradiation ...

Journal: :Molecules 2017
Chih-Wei Chang Ching-Chi Yen Ming-Tsang Wu Mei-Chich Hsu Yu-Tse Wu

Hemp nut is commonly incorporated into several food preparations; however, most countries set regulations for hemp products according to their cannabinoid content. In this study, we have developed an efficient microwave-assisted extraction (MAE) method for cannabinoids (i.e., Δ9-tetrahydrocannabinol, cannabidiol, and cannabinol) in hemp nut. Optimization of the MAE procedure was conducted throu...

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