scholarly journals Effect of externally adding pyrite and electrical current on galvanic leaching of chalcopyrite concentrate

2021 ◽  
Vol 57 (2) ◽  
pp. 105-119
Author(s):  
Kaveh Asgari ◽  
Ahmad Hassanzadeh ◽  
Sabereh Nazari ◽  
Ali Behrad Vakylabad ◽  
Mostafa Hosseinzadeh
Keyword(s):  
Electrical Current ◽  
Chalcopyrite Concentrate

The Role of Computer Modeling in Electrocardiography

1990 ◽  
Vol 29 (04) ◽  
pp. 282-288 ◽  
Author(s):  
A. van Oosterom
Keyword(s):  
Electrical Activity ◽  
Computer Modeling ◽  
Body Surface ◽  
Electrical Current ◽  
The Body ◽  
Volume Conductor ◽  
Current Generator ◽  
Cardiac Electrical Activity ◽  
Source Models

AbstractThis paper introduces some levels at which the computer has been incorporated in the research into the basis of electrocardiography. The emphasis lies on the modeling of the heart as an electrical current generator and of the properties of the body as a volume conductor, both playing a major role in the shaping of the electrocardiographic waveforms recorded at the body surface. It is claimed that the Forward-Problem of electrocardiography is no longer a problem. Several source models of cardiac electrical activity are considered, one of which can be directly interpreted in terms of the underlying electrophysiology (the depolarization sequence of the ventricles). The importance of using tailored rather than textbook geometry in inverse procedures is stressed.

Integration of Multi-geophysical Approaches to Identify Potential Pathways of Heavy Metals Contamination - A Case Study in Zeida, Morocco

2020 ◽  
Vol 25 (3) ◽  
pp. 415-423
Author(s):  
Ahmed Lachhab ◽  
El Mehdi Benyassine ◽  
Mohamed Rouai ◽  
Abdelilah Dekayir ◽  
Jean C. Parisot ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Electrical Current ◽  
P Wave ◽  
Low Resistivity ◽  
Refraction Tomography ◽  
Geophysical Surveys

The tailings of Zeida's abandoned mine are found near the city of Midelt, in the middle of the high Moulouya watershed between the Middle and the High Atlas of Morocco. The tailings occupy an area of about 100 ha and are stored either in large mining pit lakes with clay-marl substratum or directly on a heavily fractured granite bedrock. The high contents of lead and arsenic in these tailings have transformed them into sources of pollution that disperse by wind, runoff, and seepage to the aquifer through faults and fractures. In this work, the main goal is to identify the pathways of contaminated water with heavy metals and arsenic to the local aquifers, water ponds, and Moulouya River. For this reason, geophysical surveys including electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and very low-frequency electromagnetic (VLF-EM) methods were carried out over the tailings, and directly on the substratum outside the tailings. The result obtained from combining these methods has shown that pollutants were funneled through fractures, faults, and subsurface paleochannels and contaminated the hydrological system connecting groundwater, ponds, and the river. The ERT profiles have successfully shown the location of fractures, some of which extend throughout the upper formation to depths reaching the granite. The ERT was not successful in identifying fractures directly beneath the tailings due to their low resistivity which inhibits electrical current from propagating deeper. The seismic refraction surveys have provided valuable details on the local geology, and clearly identified the thickness of the tailings and explicitly marked the boundary between the Triassic formation and the granite. It also aided in the identification of paleochannels. The tailings materials were easily identified by both their low resistivity and low P-wave velocity values. Also, both resistivity and seismic velocity values rapidly increased beneath the tailings due to the compaction of the material and lack of moisture and have proven to be effective in identifying the upper limit of the granite. Faults were found to lie along the bottom of paleochannels, which suggest that the locations of these channels were caused by these same faults. The VLF-EM surveys have shown tilt angle anomalies over fractured areas which were also evinced by low resistivity area in ERT profiles. Finally, this study showed that the three geophysical methods were complementary and in good agreement in revealing the pathways of contamination from the tailings to the local aquifer, nearby ponds and Moulouya River.

Design and Evaluation of a Modulated TENS Stimulation in Medical Pain Therapy

2019 ◽  
Vol 14 (1) ◽  
pp. 75-83
Author(s):  
L. Bouafif ◽  
N. Ellouze
Keyword(s):  
Pain Intensity ◽  
Nerve Stimulation ◽  
Transcutaneous Electrical Nerve Stimulation ◽  
Pain Therapy ◽  
Subjective Evaluation ◽  
Large Population ◽  
Electrical Current ◽  
Control Group ◽  
Controlled Clinical Trial ◽  
Electrical Nerve Stimulation

Background: Transcutaneous Electrical Nerve Stimulation (TENS) is a non-invasive pain therapy that uses the sensory effects of an electrical current applied to the skin. Some clinical studies demonstrated that this treatment helps to reduce acute and chronic pains, while others gave sometimes contradictory or uncertain conclusions about the performances of this strategy according to pathology classification. The purpose of this study is the development and evaluation of a new modulated version of transcutaneous electrical nerve stimulation called PWM-TENS. The principle is based on an automatic variation of the stimulation parameters (frequency, amplitude, duration, shape, cyclic ratio) according to the pain evolution. Methods: The study was a controlled clinical trial involving 15 participants, divided into 2 groups. The first experimental group performed modulated PWM-TENS electro-stimulation sessions applied to the painful areas 3 to 4 times a day, for one month. The second control group did parallel treatments by Placebo. The evaluation of the pain intensity is done with the Visual Analog Scale (EVA), the DN4 and SF36 questionnaires. Results: The tests and measurements with our embedded PWM-TENS technique demonstrated that we succeeded to increase the analgesic effect after stopping the stimulation and reduced the pain sensation by about 60%. An improvement in pain intensity scores and questionnaires (EVA, DN4), as well as the quality of life score (SF36), was observed. Also, a reduction of the treatment period from 3 to 1 month was also obtained. Conclusion: The first results clinically observed in the PWM-TENS technique are encouraging. The findings of this study confirm that this noninvasive strategy is suitable and useful for acute pains coming from the nociceptive, neuropathic and musculoskeletal origin. However, its efficiency is moderated and less adapted for low back pain. The experiments make it possible to estimate whether this modulated TENS method could improve existing anti-pain therapies, taking into account objective and subjective evaluation criteria. But this study must be followed by large population samples to answer all the problems of acute and chronic pains.

Investigating and Optimization of Copper Extraction from Chalcopyrite Concentrate with Hydrogen Peroxide in Presence of Acetic Acid

2017 ◽  
Vol 7 (4) ◽  
Author(s):  
Mehmat Deniz Turan ◽  
Musa Sarikaya ◽  
Z. Abidin Sari ◽  
Ahmet Haxhiaj ◽  
Tolga Depci ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Copper Extraction ◽  
Chalcopyrite Concentrate

scholarly journals Modulation of Human Mesenchymal Stem Cells by Electrical Stimulation Using an Enzymatic Biofuel Cell

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Won-Yong Jeon ◽  
Seyoung Mun ◽  
Wei Beng Ng ◽  
Keunsoo Kang ◽  
Kyudong Han ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Electrical Stimulation ◽  
Regenerative Medicine ◽  
Cell Morphology ◽  
Electrical Current ◽  
Specific Gene ◽  
Next Generation ◽  
The Impact

Enzymatic biofuel cells (EBFCs) have excellent potential as components in bioelectronic devices, especially as active biointerfaces to regulate stem cell behavior for regenerative medicine applications. However, it remains unclear to what extent EBFC-generated electrical stimulation can regulate the functional behavior of human adipose-derived mesenchymal stem cells (hAD-MSCs) at the morphological and gene expression levels. Herein, we investigated the effect of EBFC-generated electrical stimulation on hAD-MSC cell morphology and gene expression using next-generation RNA sequencing. We tested three different electrical currents, 127 ± 9, 248 ± 15, and 598 ± 75 nA/cm2, in mesenchymal stem cells. We performed transcriptome profiling to analyze the impact of EBFC-derived electrical current on gene expression using next generation sequencing (NGS). We also observed changes in cytoskeleton arrangement and analyzed gene expression that depends on the electrical stimulation. The electrical stimulation of EBFC changes cell morphology through cytoskeleton re-arrangement. In particular, the results of whole transcriptome NGS showed that specific gene clusters were up- or down-regulated depending on the magnitude of applied electrical current of EBFC. In conclusion, this study demonstrates that EBFC-generated electrical stimulation can influence the morphological and gene expression properties of stem cells; such capabilities can be useful for regenerative medicine applications such as bioelectronic devices.

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