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With the development of intelligent modern power systems, real-time sensing and monitoring of system operating conditions have become one of the enabling technologies. Due to their flexibility, robustness and broad serviceable scope, wireless sensor networks have become a promising candidate for achieving the condition monitoring in a power grid. In order to solve the problematic power supplies of the sensors, energy harvesting (EH) technology has attracted increasing research interest. The motivation of this paper is to investigate the profiles of harnessing the electric and magnetic fields and facilitate the further application of energy scavenging techniques in the context of power systems. In this paper, the fundamentals, current status, challenges, and future prospects of the two most applicable EH methods in the grid—magnetic field energy harvesting (MEH) and electric field energy harvesting (EEH) are reviewed. The characteristics of the magnetic field and electric field under typical scenarios in power systems is analyzed first. Then the MEH and EEH are classified and reviewed respectively according to the structural difference of energy harvesters, which have been further evaluated based on the comparison of advantages and disadvantages for the future development trend.

Mixed convection flow and heat transfer within various cavities including lid-driven walls has many engineering applications. Investigation of such a problem is important in enhancing the performance of the cooling of electric, electronic and nuclear devices and controlling the fluid flow and heat exchange of the solar thermal operations and thermal storage.The main aim of this fundamental investigation is to examine the influence of a two-phase hybrid nanofluid approach on mixed convection characteristics including the consequences of varying Richardson number, number of oscillations, nanoparticle volume fraction, and dimensionless length and dimensionless position of the solid obstacle.The migration of composite hybrid nanoparticles due to the nano-scale forces of the Brownian motion and thermophoresis was taken into account. There is an inner block near the middle of the enclosure, which contributes toward the flow, heat, and mass transfer. The top lid cover wall of the enclosure is allowed to move which induces a mixed convection flow. The impact of the migration of hybrid nanoparticles with regard to heat transfer is also conveyed in the conservation of energy. The governing equations are molded into the non-dimensional pattern and then explained using the finite element technique. The effect of various non-dimensional parameters such as the volume fraction of nanoparticles, the wave number of walls, and the Richardson number on the heat transfer and the concentration distribution of nanoparticles are examined. Various case studies for Al2O3-Cu/water hybrid nanofluids are performed.The results reveal that the temperature gradient could induce a notable concentration variation in the enclosure.The location of the solid block and undulation of surfaces are valuable in the control of the heat transfer and the concentration distribution of the composite nanoparticles.

HighlightsThe main problem to ensure the good management in fisheries was multi species fishPrecautionary approach needed to get a good view of the important criteria in fisheries managementNeeded a multi criteria and index to make a final conclusion of the any criteriaNatural history and population dynamic parameter important input to sustainability indexValidation model in sunda strait as preliminary approach will help to get a good data and resultAbstractTorpedo scad species known are both economic and ecologic important pelagic fish that fishing catch tends to increase last a few decades. For sustainability, in the long term, needed a management strategy that complies with measurable fish population indicators. This effort is a part of the precautionary approach in fiseries management in related exploitation. This research was conducted in Labuan fishing port performed for more than 8 months and then analyzed with population parameters. Composite analysis by multi-criteria approaches found that the average score of Torpedo scad is 1.48 and then grouped as moderate sustainability. Schooling fish, including torpedo scad has been moderate until high sustainability levels. Overall population status in this area refer to moderate potential risk and needs a precautionary approach on management. 

To fulfill the ever-increasing power demands of deep space exploration, the output performance of radioisotope thermoelectric generators, the only accessible power source, must be enhanced in several aspects, including thermoelectric properties of materials, geometry, welding, etc. In this study, we present our results on the development of a novel thermoelectric slurry suitable for the 3D printing of thermoelectric generators with optimized leg geometry. The rheological properties of the slurry are optimized by combining proper amounts of organic solvent, binder, and bismuth telluride-based thermoelectric powder. The addition of Cu to the slurry as a conductive additive are also investigated. The homogeneous dispersion of Cu within the material not only increases the electrical conductivity of the final thermoelectric leg significantly but also promotes the crystallization of the thermoelectric particles during the sintering process. These effects result in 3D-printed thermoelectric composites exhibiting ZT values up to 0.91 and extended optimum operating temperature range. Thermoelectric modules composed of 3D-printed thermoelectric legs show excellent output performance and structural strength. This work could also produce other special shaped thermoelectric devices to match irregularly shaped heat sources to reduce contact heat loss and improve output performance.

Les catalyseurs hétérogènes sont souvent utilisés dans leur ensemble pour produire du biodiesel à partir d'huiles brutes végétales non comestibles telles que l'huile de Jatropha curcas (JCO). Dans cette étude, un catalyseur de CaO hétérogène actif a été synthétisé à partir d'un coquillage de biodiversité tropicale Anadara granosa (A.granosa). L'efficacité catalytique de A.granosa CaO a été étudiée dans la transestérification de JCO sous forme de biodiesel. Le catalyseur A.granosa CaO a été synthétisé en utilisant le protocole « Calcination – hydratation – déshydratation ». La caractérisation spectrale du catalyseur a été étudiée en utilisant des techniques spectrographiques FT-IR, SEM, BET et BJH. La conception expérimentale a été exécutée avec quatre paramètres de réaction qui comprennent la concentration du catalyseur (CC), le taux de méthanol (MR), le temps de transestérification (TT) et la température de réaction (RT). Les réactions de transestérification de JCO ainsi que l'impact des paramètres de réaction sur le rendement en biodiesel de Jatropha (JBY) ont été analysés. La suffisance des résultats expérimentaux était conforme grâce à des tests de validation séquentiels, en conséquence, une moyenne de 96,2% JMY a été notée dans des conditions paramétriques optimales, CC de 3wt. %, TT de 120 min, MR de 5 mol. et RT de 60ºC à une vitesse d'agitation constante de 300 tr/min. Une JMY moyenne de 87,6 % a été obtenue à partir du catalyseur A.granosa CaO lors de leurs études de recyclage et de réutilisation jusqu'au troisième cycle de réutilisation. Los catalizadores heterogéneos se utilizan a menudo en general para producir biodiésel a partir de aceites crudos vegetales no comestibles, como el aceite de Jatropha curcas (JCO). En este estudio, se sintetizó un catalizador de CaO heterogéneo activo a partir de conchas marinas de biodiversidad tropical Anadara granosa (A.granosa). Se investigó la eficiencia catalítica de A.granosa CaO en la transesterificación de JCO como biodiesel. El catalizador de CaO de A.granosa se sintetizó utilizando el protocolo 'Calcinación – hidratación – deshidratación'. La caracterización espectral del catalizador se investigó empleando técnicas espectrográficas FT-IR, SEM, BET y BJH. El diseño experimental se ejecutó con cuatro parámetros de reacción que incluyen concentración de catalizador (CC), relación de metanol (MR), tiempo de transesterificación (TT) y temperatura de reacción (RT). Se analizaron las reacciones de transesterificación de JCO, así como el impacto de los parámetros de reacción en el rendimiento de biodiésel de Jatropha (JBY). La suficiencia de los resultados experimentales se conformó a través de pruebas de validación secuencial, como resultado, se observó un promedio de 96.2% de JMY en condiciones paramétricas óptimas, CC de 3wt. %, TT de 120 min, MR de 5 mol. y RT de 60ºC a una velocidad de agitación constante de 300rpm. Se obtuvo un JMY medio del 87,6% del catalizador de Cao de A.granosa durante sus estudios de reciclaje y reutilización hasta el tercer ciclo de reutilización. Heterogeneous catalysts are often used at large to produce biodiesel from non-edible vegetable crude oils such as Jatropha curcas oil (JCO). In this study, an active heterogeneous CaO catalyst was synthesized from a tropical biodiversity seashells Anadara granosa (A.granosa). The catalytic efficiency of A.granosa CaO was investigated in transesterification of JCO as biodiesel. The A.granosa CaO catalyst was synthesized using 'Calcination – hydration – dehydration' protocol. The spectral characterization of the catalyst were investigated by employing FT-IR, SEM, BET and BJH spectrographic techniques. The experimental design was executed with four reaction parameters that include catalyst concentration (CC), methanol ratio (MR), transesterification time (TT) and reaction temperature (RT). The JCO transesterification reactions as well as impact of reaction parameters on the Jatropha biodiesel yield (JBY) were analyzed. The sufficiency of the experimental results conformed through sequential validation tests, as a result, an average of 96.2% JMY was noted at optimal parametric conditions, CC of 3wt. %, TT of 120 min, MR of 5 mol. and RT of 60ºC at a constant agitation speed of 300rpm. An average JMY of 87.6% was resulted from the A.granosa CaO catalyst during their recycling and reuse studies up to third reuse cycle. غالبًا ما تستخدم المحفزات غير المتجانسة بشكل عام لإنتاج الديزل الحيوي من الزيوت الخام النباتية غير الصالحة للأكل مثل زيت جاتروفا كركاس (JCO). في هذه الدراسة، تم تصنيع محفز CaO غير متجانس نشط من أصداف البحر الاستوائية للتنوع البيولوجي Anadara granosa (A.granosa). تم التحقيق في الكفاءة التحفيزية لـ A.granosa CaO في تحويل JCO كديزل حيوي. تم تصنيع محفز A.granosa CaO باستخدام بروتوكول "التكليس – الترطيب – التجفيف". تم التحقيق في التوصيف الطيفي للمحفز من خلال استخدام تقنيات FT - IR و SEM و BET و BJH الطيفية. تم تنفيذ التصميم التجريبي بأربعة معلمات تفاعل تشمل تركيز المحفز (CC) ونسبة الميثانول (MR) وزمن التحويل (TT) ودرجة حرارة التفاعل (RT). تم تحليل تفاعلات التحويل JCO بالإضافة إلى تأثير معلمات التفاعل على محصول الديزل الحيوي Jatropha (JBY). تمت مطابقة كفاية النتائج التجريبية من خلال اختبارات التحقق المتسلسلة، ونتيجة لذلك، لوحظ متوسط 96.2 ٪ JMY في الظروف البارامترية المثلى، CC من 3wt. ٪، TT من 120 دقيقة، MR من 5 مول. و RT من 60 درجة مئوية عند سرعة تحريك ثابتة تبلغ 300 دورة في الدقيقة. نتج متوسط JMY بنسبة 87.6 ٪ من محفز A.granosa CaO أثناء دراسات إعادة التدوير وإعادة الاستخدام حتى دورة إعادة الاستخدام الثالثة.

To stabilize frequency in a power system, this research study suggests a novel modified Gorilla Troops Optimizer (mGTO) technique, which builds on the original technique, and offers notable gains in effectiveness and efficiency when solving real-world optimization problems. A thorough comparative analysis reveals that the mGTO algorithm is the best option, outperforming its counterparts in terms of stability and overall performance. Interestingly, mGTO performs better than any of its competitors in terms of stability, making it the best option. The mGTO algorithm significantly reduces implementation time and enhances solution quality compared to the conventional GTO algorithm. A new linearized Phillips–Heffron model with an IPFC was developed to investigate power systems’ stability. To effectively dampen low-frequency oscillations, an auxiliary controller for modeling the IPFC is proposed. It provides four options for damping controllers, and the recommended mGTO algorithm is used to adjust the controller parameters. This method is superior to traditional controllers in stability control and has undergone extensive validation. It is a crucial instrument for controlling the frequency of an SMIB power system based on IPFC. Based on the simulation results, the updated strategy that has been suggested is the most effective way to define the mentioned damping controller by considering the percentage improvement in the goal function value.