extraction power
Recently Published Documents


TOTAL DOCUMENTS

25
(FIVE YEARS 10)

H-INDEX

5
(FIVE YEARS 1)

Author(s):  
Amit Singh ◽  
Sarthak Saxena ◽  
Ritika Chowdhary ◽  
Rishant Pal ◽  
Monu Kumar ◽  
...  

Oceans are consequential provenance of resources, transportation and bio-diversity on a grand scale. Humankind uses oceans for various motives such as haulage, victuals, trade, mineral extraction, power generation, warfare, sustention and leisure. Many of these activities fabricate marine pollution and straining in sustaining aquatic life, despite several protection barriers.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3835
Author(s):  
Jing Liu ◽  
Chaochan Li ◽  
Guijie Ding ◽  
Wenxuan Quan

Flavonoids in Rosa sterilis were studied. The flavonoids in Rosa sterilis were extracted by ultrasonic method, and the extraction conditions were modeled and optimized by response the surface methodology and the artificial intelligence method. The results show that the ultrasonic method can effectively extract total flavonoids, and the extraction rate is close to the prediction value of ANN-GA algorithm, which proves the rationality of the model. The order of the effects of the parameters on the experiment was material liquid ratio > extraction power > extraction time > ethanol concentration. In addition, the scavenging effects of flavonoids on DPPH, O2−· and ·OH were also determined, and these indicated that flavonoids have strong antioxidant activities. The kinetics of the extraction process was studied by using the data of the extraction process, and it was found that the extraction process conformed to Fick’s first law.


Author(s):  
Essam Hendawi

<p>This paper presents an effective single phase grid connected photovoltaic PV system based on High Efficiency and Reliable Inverter Concept HERIC transformerless inverter.  dc-dc boost converter controlled by incremental conductance IC maximum power point tracker MPPT is employed to achieve the maximum extraction power of the PV panels.  Proportional integral PI controller controls the output voltage of the boost converter to meet the utility grid requirements.  LCL filter is utilized to keep the inverter voltage very close to sinusoidal shape.   Employing the HERIC transformerless inverter reduces significantly the ground leakage current beyond safe limits.  Semiconductors losses are studied to investigate the efficiency of the proposed system at different insolation levels.  Simulation results verify the high performance of the proposed system when considering leakage current and system efficiency.</p>


2020 ◽  
Vol 71 (4) ◽  
pp. 601-614
Author(s):  
Mingjun Yang ◽  
Avwenagbiku O Mercy ◽  
Nehikhare Efehi ◽  
Mussifulina Venera ◽  
Xiaofeng Liu ◽  
...  

Leonurus japonicus is rich in bioactive compounds especially polysaccharide. Single factors test and response surface methodology were used to study the optimum conditions for ultrasonic - assisted extraction of polysaccharide from L. japonicus, and its physiochemical and DPPH scavenging activities also were evaluated. The optimal conditions as underpinned by this paper is as follow: extraction temperature of 70 �C, extraction time of 50 min and extraction power of 210W. The polysaccharide of L. japonicus was shown to be a non-reducing sugar and to exhibit DPPH scavenging activity to an extent. The polysaccharide structures were studied using SEM, AFM, and FT-IR. It showed L. japonicus polysaccharide had been having more than one chains which were branched and entangled with each other. and existed a broad band wavelength of 2925.64, 1635.06, 1539.7, 1046.73, and 477.86 cm-1. The study indicated that L. japonicus may have a beneficial use to the medical and food industries.


2020 ◽  
Vol 2 (1) ◽  
pp. 72-75
Author(s):  
Kasimu Abubakar ◽  
Assoc. Prof. Dr. Azli Sulaiman ◽  
Jamilu Usman

Technological advancement over the past decade has dramatically changed with new players such as China taking lead in information-technology and telecommunication market across the world. This development has seen surge in manufacturing industry output and consequently raw materials consumed by the sector. The environmental impact is however evident due to human interference with nature. E-waste is the fastest growing waste stream posing serious risk to fauna and flora due to numerous associated pollutants. In recycling industry, hydrometallurgy is widely adopted to recover metals from e-waste. Despite growing concern over secondary pollution associated with disposal, concentrated aqua regia is widely used to extract metals from e-waste. An ultrasonic bath enhanced dilute-acid leaching method was developed to recover copper and lead from waste mobile phone PCB. Repeatability and reproducibility showed 5.3% and 5.0% with respect to Cu while 9.8% and 6.3% RSD were recorded for lead. LOD and LOQ of 0.02 µg/g and 0.064 µg/g (Cu) and 0.082 µg/g and 0.312 µg/g (Pb) revealed that the method is suitable for dissolution of target metals from PCBs. Copper concentration of 332.98 mg/g recorded inferred that dilute aqua regia as much as concentrated has promising metal extraction power and thus could replace concentrated acids.


Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1226
Author(s):  
Yangyang Zhang ◽  
Li Yu ◽  
Weifeng Jin ◽  
Chang Li ◽  
Yu Wang ◽  
...  

An evaluation of the ultrasonic extraction process and the antioxidant activities of hydroxysafflor yellow A (HSYA) and anhydrosafflor yellow B (AHSYB) from safflower are presented herein. Using response surface methodology (RSM), based on a four-factor-three-level Box–Behnken design (BBD), the extraction parameters, namely, temperature, extraction time, solvent-to-material ratio, and extraction power, were optimized for maximizing the yields of HSYA and AHSYB. The maximum yield was obtained at a temperature of 66 °C with an extraction time of 36 min, solvent-to-material ratio of 16 mL/g, and the extraction power of 150 W, which was adjusted according to the actual conditions. The HSYA and AHSYB contents were determined using high performance liquid chromatography (HPLC). The yield and the comprehensive evaluation value of HSYA and AHSYB were calculated. The antioxidant activities of the extracts were determined using a ferric reducing antioxidant power (FRAP) kit and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. The results suggested that the safflower extracts possessed obvious ferric reducing and DPPH radical scavenging activities. The antioxidant activity increased with increasing concentration. The results suggested that optimizing the conditions of ultrasonic extraction using RSM can significantly increase the yields of HSYA and AHSYB from safflower. The safflower extracts showed better antioxidant activity. This study can encourage future research on cardiovascular and cerebrovascular diseases.


Econometrica ◽  
2020 ◽  
Vol 88 (5) ◽  
pp. 1939-1963 ◽  
Author(s):  
Vahab Mirrokni ◽  
Renato Paes Leme ◽  
Pingzhong Tang ◽  
Song Zuo

We introduce a new family of dynamic mechanisms that restricts sellers from using future distributional knowledge. Since the allocation and pricing of each auction period do not depend on the type distributions of future periods, we call this family of dynamic mechanisms non‐clairvoyant. We develop a framework (bank account mechanisms) for characterizing, designing, and proving lower bounds for dynamic mechanisms (clairvoyant or non‐clairvoyant). We use the same methods to compare the revenue extraction power of clairvoyant and non‐clairvoyant dynamic mechanisms.


Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3481 ◽  
Author(s):  
Cinzia Benincasa ◽  
Ilaria Santoro ◽  
Monica Nardi ◽  
Alfredo Cassano ◽  
Giovanni Sindona

Olive tree (Olea europaea L.) leaf, a waste by-product of the olive oil industry, is an inexpensive and abundant source of biophenols of great interest for various industrial applications in the food supplement, cosmetic, and pharmaceutical industries. In this work, the aqueous extraction of high-added value compounds from olive leaves by using microfiltered (MF), ultrapure (U), and osmosis-treated (O) water was investigated. The extraction of target compounds, including oleuropein (Olp), hydroxytyrosol (HyTyr), tyrosol (Tyr), verbascoside (Ver), lutein (Lut), and rutin (Rut), was significantly affected by the characteristics of the water used. Indeed, according to the results of liquid chromatography tandem mass spectrometry, the extracting power of microfiltered water towards rutin resulted very poor, while a moderate extraction was observed for oleuropein, verbascoside, and lutein. On the other hand, high concentrations of hydroxytyrosol were detected in the aqueous extracts produced with microfiltered water. The extraction power of ultrapure and osmosis-treated water proved to be very similar for the bio-active compounds oleuropein, verbascoside, lutein, and rutin. The results clearly provide evidence of the possibility of devising new eco-friendly strategies based on the use of green solvents which can be applied to recover bioactive compounds from olive leaves.


2019 ◽  
Vol 75 (4) ◽  
pp. 330-337
Author(s):  
M. C. Huang ◽  
C. D. Hu ◽  
C. C. Jiang ◽  
Y. Z. Zhao ◽  
Y. H. Xie ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document