Deep Eutectic Mn(NO3)2−H2O Binary System as a Safe, Cost-Effective, and Efficient Electrolyte for Supercapacitor Applications

Deep eutectic solvents (DESs) have proved to be an effective substitute for conventional electrolytes for energy storage applications because of their unique properties and ability to adapt them to specific applications. In this regard, this study examines an easy-to-produce, widely available and cheap manganese nitrate concentrated electrolyte that holds DES traits. The electrolyte (i. e., manganese nitrate; (Mn(NO3)2 ⋅ 6H2O with a weight composition of 42 %) revealed its eutectic behaviour by benchmarking the eutectic distance (53 °C), thermal expansion coefficient (3.9×10−4 K), activation energy for conductivity (∼2.45 kJ mol−1), and viscosity (14 kJ mol−1). What's more, it was successfully incorporated into a two-electrode symmetric supercapacitor comprising activated carbon electrodes and demonstrated specific capacitance retention of 93 % (170 F g−1) through 2000 consecutive galvanostatic charge-discharge cycles at 25 and −20 °C

Sukuk-waqf: The Islamic Solution for Public Finance Deficits

The majority of Muslim countries face increasing pressure on their budget, which pushes to more public spending. Eventually, the main victim of this situation will be the welfare of Muslim communities. Despite Islam does not tolerate negligence regarding the importance of State as major player in preserving the welfare of Muslim communities, it offers a third option to support public effort through the institution of Waqf. Indeed, this institution has played a crucial role all along Muslim civilization and it is invited to more innovation to answer to today’s challenges. Sukuk-Waqf can be seen as the perfect sustainable financing instrument offered by Islam to help sustain public spending by the people and for the people. This paper will try to examine the concept of Waqf, cash Waqf and Sukuk Waqf is Islam and their evolution during Muslim civilization. Finally, it will go through modern attempts to implement this model that can answer the need for financing to support public effort to preserve the welfare of Muslim citizens

Shari’ah-compliant Stock Screening: A Financial Perspective

Stock markets have always provided countries with a practical and flexible way to finance their economies. Hence, Islamic finance has embraced the stock market since the early 90s adopting the same framework as an ethical investment. Accordingly, Islamic investors in emerging countries shall have a range of choices when constructing a financial portfolio. However, existing screening methodologies lack flexibility as they are mainly based on rigid ratios and irrelevant thresholds. Consequently, these methodologies lead to an inefficient stock index as they completely ignore the features of each stock market along with the specificities of each industry. Thus, our study will try to propose a new screening methodology based on the optimal financial structure of each industry. The main objective of our study is to propose a methodology that will overcome different loopholes addressed in the literature. The present paper is an explanatory study which needs an empirical confirmation of the proposed methodology in order to measure its performance and efficiency against existing shari’ah-compliant indices. Hence, the main preliminary finding of our research is to enrich the academic debate on shari’ah-compliant screening methodologies through appealing to conventional corporate finance framework to enhance current methodologies

Capital Structure Determinants of Shariah-Compliant Firms: Evidence from the MENA Region

Capital structure choice is vital in corporate financial management due to its effect on both investors' risk and return. Despite the various research that has investigated factors affecting the capital structure of companies, only a few studies have started to examine the capital structure of Shari'ah-compliant companies, especially in the MENA region. Indeed, the screening requirements for which shari'ah-compliant must adhere can affect their capital structure determinants. Hence, under those conditions, this study aims to determine the factors influencing the capital structure of a shari'ah-compliant listed firm in five MENA region countries. The importance of investigating shariah-complaint companies capital structure emanates from the financial constraints on their debt capital structure. Accordingly, this study utilizes static panel data techniques on a sample consisting of Shari'ah-compliant firms over the period 20102018. The findings of this study were consistent with several previous studies as well as the theoretical background of capital structure determinants mainly, the trade-off and the pecking order theory. Our results give insight to managers on what determines their capital structure under shari'ah screening methodologies. However, more insight can be drought from the capital structure of shari'ah-compliant firms by extending the research into industry specifics

An Overview on the Practice and Issues of Hedging in Islamic Finance

In terms of Islamic banking, which relies on three main pillar of prohibiting Riba, Gharar& Maysir, risk management is still not sufficiently developed. Indeed, Islamic use traditional types of risk management instruments used by conventional banks. Despite Islamic banking has a specific characteristic related essentially to the Profit & Loss Sharing (PLS) principle in Mudarabah & Musharakah contracts. Such instruments change the classic concept of risk in comparison with conventional banks adding new types of risk such as Commodity/Asset price risk and Bundled risk along with neutralizing other type of risks like the liquidity risk. Nevertheless, the rigidity of some Sharia’a scholars has impeded some financial instruments that try to match the real risk management demands by business entities in the global Islamic finance industry. Indeed, it has been widely acknowledged by many observers that the Islamic finance industry will not be able to sustainably continue on this growth trajectory, and may even regress, without a proper market risk management framework that can effectively deal with the complex risks that exist in today’s globalized economy (Chapra& Khan, 2000; Moody's, 2010).The present research article is an attempt to analyze hedging instruments from an Islamic finance perspective. It will approach different fiqhi ruling on them along with the applicability of these instruments in the reality

ISLAMIC BANKS, LIQUIDITY MANAGEMENT AND RISK-SHARING

Bank liquidity stands as a key pillar in the survival of the financial system as it reflects its robustness and maturity. On the other hand, the recent introduction of Islamic banks in Morocco has provided a new ground to re-think the ongoing practices of liquidity Revue Économie, Gestion et Société N°21 août 2019 2 management. In fact, these practices have relied on questionable mechanism like Tawarruq that deviates from the basic principles of Islamic finance. Researchers agree that Risk-sharing stands in the center of the Islamic finance and therefore, is presented as an optimal model for an efficient banking model. However, operational constraints along with rigid regulatory framework have put this model on hold for years. (Bacha & Mirakhor, 2017)proposed a genuine model based on Risk-sharing that provides a complete banking structure that will enable Islamic banks to manage their liquidity along with optimizing their risk exposure. The proposed model is fully based on Risk-sharing and shari’ah-compliant instruments namely Sukuk. Hence, our paper aims to present the banking model along with the perspective of its application on the Moroccan case. We find that two main obstacles shall impede its application which is the operational and regulatory framework. Nevertheless, the first point could be easily being overcome with the maturity of the interbank market and the second point’s solution relies solely on the governmental will to develop the Islamic finance industry

Study of limiting processes of power performance within Li-ion batteries

De nos jours, grâce à de nombreux avantages, notamment une haute densité d’énergie, une longue durée de vie, et un rendement élevé, les batteries Li-ion sont prédominantes pour alimenter les appareils électroniques comme les téléphones et ordinateurs portables. De plus, leur utilisation s’est élargie à grande échelle comme système de stockage d’énergie pour les véhicules électrifiés et les applications stationnaires. Néanmoins, pour répondre aux exigences du marché du transport électrique et étendre la pénétration des batteries au Li dans ce secteur, des améliorations sont nécessaires, notamment en termes de densité d’énergie, de sécurité, et de durée de vie. En plus du développement de matériaux actifs, plusieurs approches sont proposées et étudiées en vue d’augmenter l’autonomie des batteries. Parmi elles, une consiste à optimiser le design de l'électrode composite à savoir la porosité, le grammage, la composition et la microstructure. Cela revient à augmenter le ratio des matériaux actifs (épaisseur d’électrode positive et négative) par rapport aux autres composants inactifs à savoir les collecteurs de courant et le séparateur. Cependant, pour les électrodes fortement grammées la capacité de décharge devient limitée par le transport de charges au sein de l’électrode, notamment à fort courant, ce qui implique une forte diminution de la densité de puissance.Ce projet de thèse a pour but d’étudier la capacité restituée dans les batteries au Li en fonction du design de l’électrode, à savoir la formulation (microstructure), la composition chimique (nature des matériaux actifs), le grammage et la porosité, mais aussi la température de travail. Pour cela, deux matériaux d’électrode positive seront étudiés à savoir LiFePO4 (LFP) et LiNi0.8Mn0.1Co0.1O2 (NMC 811), des électrodes à différents grammages (0.4 et 3.4 mAh.cm-2), et compositions, sont formulées et calandrées pour atteindre des porosités variées (20 à 50 %). La morphologie et la surface spécifique des matériaux actifs et des électrodes est investiguée via des analyses MEB, Granulométrique et BET. Ensuite, les performances en puissance de la batterie, capacité vs densité de courant, sont établies en utilisant un protocole de cyclage spécifique, permettant la détermination d’une densité de courant limite (Jlim) qui est relié au coefficient de diffusion effectif (Deff) correspondant au processus de transport limitant. En plus, la résistance de transfère de charge (Rct) en fonction de la stœchiométrie est aussi rapportée en couplant le GITT et l’EIS afin de capturer les processus physico-chimiques mis en jeu lors du fonctionnement de la batterie. Enfin, la corrélation entre le design de l’électrode, la température et les paramètres électrochimiques effectifs tel que le Deff, Jlim, and Rct seront discutés.Li-ion batteries have become a necessity in human daily life as the most versatile, efficient and performing energy storage & conversion technology, they power our nomad electronic, cars and buffer the renewable intermittent energy sources. However, improvement of current battery systems is needed to meet the requirements of the transport sector in terms of energy density, safety, and cycle life. Besides the active materials, among the strategies to increase battery autonomy, one consists in optimizing the design parameters of the electrode such as the formulation, loading, microstructure, and porosity. The idea is simply to increase the ratio of active materials (negative and positive electrode thickness) to inactive components (separator, current collector…). However, by doing so, the output power density becomes strongly limited by the charge transport within the composite electrodes, notably at high current densities.In this PhD work, Li-battery capacity is investigated as a function of the current density with respect to electrode design parameters such as porosity, formulation, loading, and microstructure as well as temperature. For this purpose, LiFePO4 (LFP) and LiNi0.8Mn0.1Co0.1O2 (NMC 811) based positive electrodes were formulated at different loadings (from 0.4 to 3.4 mAh.cm-2), compositions (Active material%, Carbon%, PVDF binder %), and calendered to reach different porosities (from 20 to 50 %). The microstructure and specific area of the active materials and the electrodes are fully characterized by SEM, Granulometry and BET. Then, the battery power performance, capacity as a function of discharge current, is fully captured and analyzed using a time-saving methodology which enables the determination of a limiting current density (Jlim) and the extraction of an effective diffusion coefficient (Deff) corresponding to the limiting transport process. In addition, the charge transfer resistance (Rct) as a function of the state of charge (SOC) is also reported by coupling GITT and EIS allowing to capture of the physico-chemical processes at stake during the battery cycling. Afterwards, the correlation between design parameters, the temperature and the effective electrochemical parameters such as Deff, Jlim, and Rct is discussed

Les cryptomonnaies et la loi islamique : quel rapprochement ?

La civilisation Humaine a adopté le concept de la monnaie de par ses bénéfices socio-économiques tout le long de son existence. Cette adoption a évalué pour s’adapter aux avances technologiques et aux besoins économiques des gens. C’est autour de cette constante évolution que le concept des monnaies cryptées (Cryptocurrencies)  a émergé suite aux séries de crises financière depuis le début du XXème siècle et qui ont mis en question la confiance des populations dans les autorités financières centrales. La technologie des registres décentralisés ainsi que celle de la cryptographie ont donné refuge à l’insatisfaction populaire envers le système monétaire traditionnel. En fait, l’Islam est avant tout un système de valeur qui vise la justice sociale, la transparence et prospérité générale. Par conséquent, on constate une convergence de ces objectifs avec ceux portes par les monnaies cryptées. C’est pour cette raison que ce papier cherche à explorer la vision de la Charia envers ces instruments et leur compatibilité avec les principes de l’économie Islamique

The Effect of Combined Therapy of Spiritual-Cognitive Group Therapy on Death Anxiety in Patients with Cancer

Introduction: The current study aims to examine the effectiveness of combined therapy of spiritual- cognitive group therapy on decreasing the death anxiety of patients with cancer who referred to cancer treatment centers of Kerman in 2012. Methods: To this aim after a clinical interview, 26 patients with cancer, referred to treatment centers, were selected using convenient sampling method. The study participants were randomly divided into two groups of control and experimental, each including 13 patients. Then, all 26 patients were scrutinized by Templar's death anxiety questionnaire. The experimental group participated in eleven 2-hour sessions of spiritual-cognitive group therapy; however, the control group received no intervention therapy. At the end, a post-test was conducted on all individuals in the sample group (26 patients). After collecting the questionnaires, the gathered data was analyzed applying SPSS software along with covariance analysis (ANCOVA). Results: The study results indicated that the combined therapy of spiritual- cognitive group therapy was significantly effective (p≤0/001) in reducing death anxiety of patients with cancer. Conclusion: The combined therapy of spiritual-cognitive group therapy can decrease the death anxiety in patients with cancer