Systematic Investigation of the Electrochemical Properties of Natural Melanin for Various Electrode Cells

2019 ◽  
Vol 13 (4) ◽  
pp. 429-437
Author(s):  
Nawal Madkhali ◽  
Adel Hassib ◽  
Hadi R. Alqahtani ◽  
Hamad Al-Britain ◽  
Seham Alterary ◽  
...  

Melanin is an organic semiconductor from a broad class of functional macromolecules found in nature. It has hybrid properties of an amorphous semiconductor. However, natural melanin has not been widely studied; this is partially due to the lack of processing methods, as melanin is generally extracted and measured as a powder. Thus, better electrical methods are required; one possible solution is the use of electrochemical synthesis. We investigated the electrochemical properties of melanin at different degrees of acidity and for various electrode cells. The electrochemical properties of natural melanin were studied using two different techniques: the constant potential method and cyclic voltammetry. This could allow different types of charge transport and make melanin a contender in this rapidly growing field. Natural melanin is believed to be a hybrid conductor where the dominant charge carriers change between electrons and protons as the acidity degree and water concentration change. Biocompatible and biodegradable features make melanin useful for electrochemical energy storage and it could be an attractive candidate for applications in bioelectronics and electronics devices.

Author(s):  
فتحي بن جمعة أحمد

ملخص البحث تعدّ هذه المحاولة في دراسة مجالات التفسير الموضوعي ومنهجية البحث فيه  مفتاحا لبعض القضايا المتعلقة بالموضوع، ومدخلا لدراسة التفسير الموضوعي يسهل على طلاب العلم والباحثين فهم كلام الله، وتدبر معانيه، والاهتداء به، والقيام ببحوث تطبيقية في مجالات التفسير الموضوعي. فقد بينت أن مجالات البحث في التفسير الموضوعي أربعة وهي البحث في المصطلح، والموضوع، والمحاور، والوحدة الموضوعيّة في السورة القرآنيّة. وقد أكدت أن البحث في محاور القرآن الكريم من مجالات البحث في التفسير الموضوعي التي لم تحظَ باهتمام الباحثين، ثم توسعت في سوق الأدلة والبراهين الدالة على أن الوحدة الموضوعية للسورة القرآنيّة مجال أساس من مجالات البحث في التفسير الموضوعي الذي لا ينبغي إغفاله، وإهمال شأنه. ثم بحثت في موضوع منهجيّة البحث في التفسير الموضوعي، ونظراً للخلط أوالاضطراب الذي بدا لدى بعض الباحثين في هذا الصدد، وضحت المقدمات المنهجيّة العامة الضرورية للبحث في التفسير الموضوعي ثم حاولت رسم الإطار التصوري والمنهجي العام والضوابط الأساسية التي يجب أن يتبعها الباحث إذا أراد الكتابة في التفسير الموضوعي. ثم بيّنت الخطوات الأساسيّة للبحث في التفسير الموضوعي ومنها حرية الباحث في اختيار موضوع بحثه والاطلاع على أكبر عدد ممكن من التفاسير بمختلف أنواعها مع الاستفادة من التراث البشري في حقول المعرفة المتنوعة على أن تكون الهيمنة للقرآن أولا وأخيرا على الكتب الأخرى والنظريات البشرية. الكلمات الرئيسة: القرآن، تفسير، موضوعي، مجالات، منهج. Abstract This article is an attempt to address the issue of the scopes and research methodology in the thematic commentary of the Holy Qur’Én. It could be considered as an introductory work for students and researchers who are interested in this field of research which will help them develop a good understanding of the meanings and teachings of the Qur’Én and its application to the real life. It may also help them undertake case studies and research in the field of thematic commentary of the Qur’Én. It has been explained in the article that the scope of the thematic commentary of the Qur’Én includes four areas; i.e. the concept, the topic, the central themes and the thematic unity of the SËrah/Chapter. The article gives a special emphasis on the study of the Qur’Énic central themes as it was overlooked by some researchers. It also provides a systematic investigation on the thematic unity of the SËrah/Chapter and considers it a significant area of research in the thematic commentary of the Qur’Én. The article also addresses the issue of the research methodology in the field of the thematic commentary of the Qur’Én. In this regard, the author highlights the principles, conditions and framework for undertaking research projects in this field of study and explains the major steps that should be followed in the execution of the research. These steps include freedom of choosing the research topic, freedom of benefitting from different types of tafsÊr (interpretation of the Qur’Én) works and schools and benefitting from the human heritage in different fields of knowledge, provided that the Qur’Én should have controlling power on other books and human theories.   Key Words: The Qur’Én, TafsÊr, Thematic, Scopes, Methodology. Abstrak Artikel ini ialah satu percubaan menangani isu  skop dan metodologi penyelidikan dalam tafsiran Al-Qur’Én Holy mengikut tema. Ia boleh dianggap sebagai satu kajian permulaan untuk pelajar-pelajar dan sarjana-sarjana yang meminati bidang ini penyelidikan yang akan membantu mereka merangka satu pemahaman yang baik tentang makna-makna dan ajaran-ajaran Qur’Én dan perlaksanaannya dalam kehidupan sebenar. Ia mungkin juga  dapat membantu mereka menjalankan kajian kes dalam bidang penyelidikan tafsiran Al-Qur’Én mengikut tema. Artikel ini akan menjelaskan  skop tafsiran Al-Qur’Én mengikut  tema ini merangkumi empat bidang:  konsep tafsiran mengikut tema, topiknya, tema-tema kecil dan tema umum Surah Al-Qur’Én. Artikel ini memberi satu penekanan khas pada kajian tafsiran Al-Qur’Én mengikut  tema kerana ia agak kurang mendapat perhatian beberapa penyelidik. Ia juga menampilkan satu kajian sistematik pada pemahaman tema Surah dalam Al-Qur’Én dan menganggapnya satu bidang penyelidikan penting dalam kajian tafsiran Al-Qur’Én mengikut tema. Artikel juga memberikan perhatian kepada bidang metodologi penyelidikan terhadap usaha tafsiran Al-Qur’Én secara bertema. Dalam hal ini, pengkaji akan menonjolkan prinsip-prinsip, syarat-syarat dan rangka kerja untuk projek-projek projek penyelidikan dalam lapangan ini dan menerangkan langkah-langkah utama yang harus diikuti dalam pelaksanaan penyelidikan yang berkenaan. Lang-langkah ini termasuk kebebasan memilih tajuk penyelidikan, kebebasan dalam mengambil  manfaat daripada jenis-jenis tafsiran Qur’Én yang berbeza serta sekolah-sekolah pemikiran yang berbeza dalam aliran tafsir serta rangka bagaimana memanfaatkan warisan tamadun manusia berlandaskan ajaran Al-Qur’Én. Kata Kunci: Al-Qur’Én, TafsÊr, Tema, Bidang-bidang, Metodologi.


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 94
Author(s):  
Petar Janjatovic ◽  
Olivera Eric Cekic ◽  
Leposava Sidjanin ◽  
Sebastian Balos ◽  
Miroslav Dramicanin ◽  
...  

Austempered ductile iron (ADI) is an advanced cast iron material that has a broad field of application and, among others, it is used in contact and for conveyance of fluids. However, it is noticed that in contact with some fluids, especially water, ADI material becomes brittle. The most significant decrease is established for the elongation. However, the influence of water and the cause of this phenomenon is still not fully understood. For that reason, in this paper, the influence of different water concentrations in ethyl alcohol on the mechanical properties of ADI materials was studied. The test was performed on two different types of ADI materials in 0.2, 4, 10, and 100 vol.% water concentration environments, and in dry condition. It was found that even the smallest concentration of water (0.2 vol.%) causes formation of the embrittled zone at fracture surface. However, not all mechanical properties were affected equally and not all water concentrations have been critical. The highest deterioration was established in the elongation, followed by the ultimate tensile strength, while the proof strength was affected least.


2005 ◽  
Vol 21 (03) ◽  
pp. 291-295
Author(s):  
DIAO Peng ◽  
◽  
MEI Gang ◽  
HOU Qun-Chao ◽  
YU Feng ◽  
...  

Author(s):  
Giuseppe Radaelli ◽  
Juan A. Gallego ◽  
Just L. Herder

Static balance can be applied to improve energy efficiency of mechanisms. In the field of static balancing, a lack of knowledge and design methods exists that are capable of dealing with torsional stiffness. This paper presents a design approach for statically balanced mechanisms, with the focus on mechanisms with torsional stiffness. The approach is graphical of nature and it is based on the requirement of constant potential energy. The first achievements of the presented approach are presented as five conceptual designs of four different types of mechanisms. One of them is developed further into a prototype, which has been tested. The prototype has a correlation coefficient of 0.96 and a normalized mean squared error of 0.12 with respect to the mechanical model of the conceptual design.


RSC Advances ◽  
2016 ◽  
Vol 6 (49) ◽  
pp. 43823-43831 ◽  
Author(s):  
S. Demirel ◽  
E. Oz ◽  
S. Altin ◽  
A. Bayri ◽  
E. Altin ◽  
...  

We report the results of a systematic investigation of structural, electrical transport, magnetic, and electrochemical properties of LiBxMn2−xO4 (where x = 0.0–1), synthesized via a one-step solid state reaction technique.


2006 ◽  
Vol 23 (4) ◽  
pp. 250-259 ◽  
Author(s):  
Vicki Bitsika

AbstractEffective behaviour change is based on understanding the reasons for difficult behaviour. However, current functional analytic technology is often limited in its effectiveness in the clinical setting because the focus is on labelling and classifying behavioural outcomes rather than conducting a detailed analysis of the manner in which these outcomes assist the client to operate in the environment. The effectiveness of existing functional analytic techniques might be enhanced by moving the focus of the investigation from identifying the consequent variables that impact on behaviour to systematically exploring client–environment interactions as well as the manner in which the client experiences the consequences of his/her actions. One potential method (Valued Outcomes Analysis) that provides a framework for the systematic investigation of the effects of ‘inner skin’ factors on the incidence of behavioural difficulties is described here.


2005 ◽  
Vol 60 (11-12) ◽  
pp. 853-860 ◽  
Author(s):  
Chao-Chen Yang ◽  
Min-Fong Shu

The electrodeposition of magnetic films of Co-Zn in zinc chloride-dimethylsulfone (ZnCl2- DMSO2) molten salt electrolytes with added CoCl2 has been studied. The phase diagram of ZnCl2- DMSO2 molten salts was determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Various compositions of alloys with different deposition potentials on the electrode surface have been studied by cyclic voltammetry. Either the constant potential method or the pulse potential method of plating can be used for electrodepositing Co-Zn thin films. The surface morphologies and magnetic properties have been studied. It has been shown that compact needle-type Co-Zn thin films are obtained at a constant potential of −0.1 V. Compact and uniform Co-Zn thin films are obtained by pulse electrodeposition. The magnetic properties of these films show higher coercive forces (Hc) and smoother domains than those obtained by the constant potential method.


2020 ◽  
Author(s):  
Nooshin Goodarzi ◽  
Hadi Tabaian ◽  
Milad Rezaei

The purpose of this study is obtaining resistant platinum coating in acidic and chloride media. In this regard, gold coating as an interlayer coated on copper substrate was selected as the most beneficial substrate for platinum plating according to the study among different substrates. In this study, Chronoamprometry (constant potential) method was conducted as the electrodeposition process and scanning electron microscope (SEM) images were utilized to investigate the coating morphology. Cyclic voltammetry (CV) tests were performed in the hydrochloric acid bath to check the durability and stability of the resultant pt. coating. The results show that the resistant platinum coating has been obtained.


2017 ◽  
Vol 8 (2) ◽  
pp. 142-150 ◽  
Author(s):  
D. M. Kabanau ◽  
Y. V. Lebiadok ◽  
P. V. Shpak ◽  
S. M. Zhuk ◽  
S. P. Stashkevich

The main object of the work was developed the device based on GaInAsSb diodes for measurement water content in oil. Optical absorption method was used in this device. Three LEDs emitting in the range from 1.6 to 2.4 μm, and one wide-band GaSb/GaInAsSb/GaAlAsSb photodiode were used as sources of radiation and detectors.The device was developed on the basis of selective optical absorption method of detection for measuring water content in oil. As sources of radiation, LEDs emitting in the range from 1.6 to 2.4 μm were used. The results of the experiments showed that the method used makes it possible to measure the water concentration in oil in the range from 0.2 to 40% with an relative error of not more than 2 %.The technical requirements and operating parameters of the used light and photodiodes were established. Investigations of the dependence of the luminescence spectra of LEDs on temperature have shown the importance of using thermal control on the sources and detectors of radiation. The possibility of using one device for different types of oil, as well as oil products during preliminary calibration were shown in the paper. The importance of using a rotary pump for mixing and pumping the analyzed medium and a flow cell was established.


2021 ◽  
Author(s):  
Liang Zeng ◽  
Taizheng Wu ◽  
Ting Ye ◽  
Tangming Mo ◽  
Rui Qiao ◽  
...  

Abstract Molecular modeling can study the energy storage of supercapacitors at the atomistic level and has become indispensable in this research. The constant potential method (CPM) allows keeping the electric potential uniform on the electrode, which is essential for a realistic description of the charge repartition and dynamics process in supercapacitors. Prior CPM studies have been limited to the potentiostatic mode. Though widely adopted in the experiment, the galvanostatic mode has been rarely investigated in CPM simulations due to a lack of effective methods. In this work, we developed a modeling approach to simulating the galvanostatic charge-discharge of supercapacitors under constant potential (GCD-CPM). We show that, for nanoporous electrodes, GCD-CPM can capture supercapacitor dynamics in excellent agreement with experimental measurements and delineate the ion adsorption-desorption dynamics underlying the hysteresis with molecular resolutions during charging and discharging. Therefore, this GCD-CPM modeling could open up new avenues for exploring the rich physics and electrochemistry of supercapacitor dynamics.


Sign in / Sign up

Export Citation Format

Share Document