5,395 research outputs found

    Hydrogen vs. Battery in the long-term operation. A comparative between energy management strategies for hybrid renewable microgrids

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    The growth of the world’s energy demand over recent decades in relation to energy intensity and demography is clear. At the same time, the use of renewable energy sources is pursued to address decarbonization targets, but the stochasticity of renewable energy systems produces an increasing need for management systems to supply such energy volume while guaranteeing, at the same time, the security and reliability of the microgrids. Locally distributed energy storage systems (ESS) may provide the capacity to temporarily decouple production and demand. In this sense, the most implemented ESS in local energy districts are small–medium-scale electrochemical batteries. However, hydrogen systems are viable for storing larger energy quantities thanks to its intrinsic high mass-energy density. To match generation, demand and storage, energy management systems (EMSs) become crucial. This paper compares two strategies for an energy management system based on hydrogen-priority vs. battery-priority for the operation of a hybrid renewable microgrid. The overall performance of the two mentioned strategies is compared in the long-term operation via a set of evaluation parameters defined by the unmet load, storage efficiency, operating hours and cumulative energy. The results show that the hydrogen-priority strategy allows the microgrid to be led towards island operation because it saves a higher amount of energy, while the battery-priority strategy reduces the energy efficiency in the storage round trip. The main contribution of this work lies in the demonstration that conventional EMS for microgrids’ operation based on battery-priority strategy should turn into hydrogen-priority to keep the reliability and independence of the microgrid in the long-term operation

    PENGARUH BRAND IMAGE DAN HARGA TERHADAP LOYALITAS PELANGGAN PADA DISTRO HYB SUPPLY

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    ABSTRAK Manajemen pemasaran merupakan seni dan ilmu untuk memilih pasar sasaran dan meraih, mempertahankan, serta menumbuhkan pelanggan dengan menciptakan, menghantarkan dan, mengkomunikasikan niai pelanggan yang unggul. Penelitian ini bertujuan untuk mengetahui seberapa besar pengaruh brand image dan harga terhadap loyalitas pelanggan pada distro Hyb Supply Bandung baik secara parsial maupun simultan. Metode penelitian yang digunakan adalah deskriptif dan verifikatif dengan jumlah sample 100 responde n. Teknik pengumpulan data yang digunakan adalah observasi, wawancara, dan menyebarkan kuisioner. Metode analisis data yang digunakan adalah regresi linier berganda, korelasi ganda dan koefisien determinasi, dan uji hipotesis. Hasil penelitian menunjukkan besar pengaruh brand image dan harga terhadap loyalitas pelanggan pada distro Hyb Supply Bandung dapat dikatakan cukup baik. Brand image memberikan pengaruh yang lebih kecil pada loyalitas pelanggan dibandingkan dengan harga terhadap loyalita pelanggan. Kata Kunci : Brand Image, Harga dan Loyalitas Pelangga

    Substituição da espiga de milho desintegrada com palha e sabugo pela mandioca integral seca na alimentação de equinos.

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    O objetivo de estudar a viabilidade da substituição parcial/total da espiga de milho desintegrada ecom palha e sabugo (MDPS) pela mandioca integral (raiz + parte aérea) seca (MIS) ao sol, na alimentação de poltras da raça Arabe, por meio de consumo, ganho de peso e coeficiente de digestibilidade(CD) da MS, PB, FB, e EB

    Björling type problems for elastic surfaces

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    In this survey we address the Bj"orling problem for various classes of surfaces associated to the Euler--Lagrange equation of the Helfrich elastic energy subject to volume and area constraints

    A 12.8 k current-mode velocity-saturation ISFET array for on-chip real-time DNA detection

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    This paper presents a large-scale CMOS chemical-sensing array operating in current mode for real-time ion imaging and detection of DNA amplification. We show that the current-mode operation of ion-sensitive field-effect transistors in velocity saturation devices can be exploited to achieve an almost perfect linearity in their input-output characteristics (pH-current), which are aligned with the continuous scaling trend of transistors in CMOS. The array is implemented in a 0.35-m process and includes 12.8 k sensors configured in a 2T per pixel topology. We characterize the array by taking into account nonideal effects observed with floating gate devices, such as increased pixel mismatch due to trapped charge and attenuation of the input signal due to the passivation capacitance, and show that the selected biasing regime allows for a sufficiently large linear range that ensures a linear pH to current despite the increased mismatch. The proposed system achieves a sensitivity of 1.03 A/pH with a pH resolution of 0.101 pH and is suitable for the real-time detection of the NDM carbapenemase gene in E. Coli using a loop-mediated isothermal amplification

    Actividad molusquicida de extractos acuosos vegetales sobre el caracol manzana pomacea canaliculata

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    En el Ecuador, entre el 40 y 48% de la producción de arroz se pierde a causa del ataque de Pomacea canaliculata, una de las cien especies invasivas más dañinas del mundo que actualmente ha infestado alrededor de 170.000 hectáreas del cultivo en todo el territorio nacional

    Impact of the Deficiency of Micronutrients on Patients with HIV/Aids

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    Introduction: HIV-AIDS is an infectious disease that damages the immune system, putting you at risk of serious infections and certain types of cancer. Micronutrient deficiency varies widely, depending on the population and stage of the disease. It can contribute to the weakening of the immune state and the worsening of the physical condition. Objective: To identify through the collection of nutritional information the consequences produced by the lack of micronutrients in patients with HIV-AIDS. Methodology: It was carried out through bibliographic reviews, scientific articles in order to find true and proven information on the effect that micronutrient deficiency has on people with HIV/AIDS. Results: It is shown that clinical deficiencies of some nutrients occur rapidly in response to dietary deficiencies, malabsorption, or altered metabolism, while those nutrients that have reserves in the body take longer to deplete. Discussion: The acquired immunodeficiency virus that causes AIDS; is associated with weight loss due to malnutrition. There are foods that can counteract many of the symptoms of the patient with HIV/AIDS, hence the importance of their knowledge. Conclusion: Micronutrient deficiency influences the immune system, accentuating the immunodeficiency that leads to AIDS. People living with this disease should have a balanced diet with Vitamins A, B, zinc and iron to strengthen the immune system, these offer a safe and economical treatment to slow the progression of the infection. Keywords: micronutrients, HIV, AIDS. RESUMEN Introducción: El VIH-SIDA es una enfermedad infecciosa que daña el sistema inmunitario lo que pone en riesgo de contraer infecciones graves y ciertos tipos de cáncer. La deficiencia de micronutrientes varía ampliamente, según la población y el estadio de la enfermedad; puede contribuir al debilitamiento del estado inmune y al empeoramiento de la condición física.  Objetivo: Identificar mediante la recopilación de información nutricional las consecuencias que produce la falta de micronutrientes en pacientes con VIH-SIDA. Metodología: Se realizó a través de revisiones bibliográficas, artículos científicos con el fin de encontrar información verídica y comprobada del efecto que tiene la deficiencia de micronutrientes en personas con VIH/SIDA.  Resultados: Se demuestra que las deficiencias clínicas de algunos nutrientes ocurren rápidamente en respuesta a deficiencias dietéticas, malabsorción, o metabolismo alterado, mientras que aquellos nutrientes que tienen reservas en el cuerpo tardan más en agotarse. Discusión: El virus de la inmunodeficiencia adquirida causante del SIDA; está asociada con la pérdida de peso por malnutrición. Hay muchos alimentos del grupo de los micronutrientes que minimizan manifestaciones clínicas en los enfermos el síndrome de inmunodeficiencia adquirida, siendo necesario saber cuáles son. Conclusiones: La deficiencia de micronutrientes influye en el sistema inmune, acentuando la inmunodeficiencia que lleva al SIDA. Las personas que viven con esta enfermedad deben tener una dieta balanceada con Vitaminas A, B, zinc y hierro para fortalecer el sistema inmunológico, estas ofrecen un tratamiento seguro y económico para retardar la progresión de la infección. Palabras claves: micronutrientes, VHI, SIDA
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