Studi Numerik Pengaruh Geometri Dan Desain Diffuser Untuk Peningkatan Kinerja DAWT (Diffuser Augmented Wind Turbine)

Numerical study was conducted on the effect a variation of flange angle on diffuser DAWT performances using Computational Fluid Dynamics (CFD). This research objective is to perform and analyze the flow characteristics such as Velocities profile and static pressure profile on the effect of diffuser\u27s flat flanged tilt angle. Verification of computation condition result by comparing data qualitative data and quantitive data Ohya\u27s experiment, (2008). Qualitative analysis showed by velocity contour, streamline contour and velocity vector. Quantitative result showed by the velocity increased profile and static pressure profile graph. The streamline of simulation result showed the bigest blockage effect due to of airflow is flange with angle 900. This effect caused the vortex formation at back side of flange. Velocity vector contour given prediction on direction of stream flow tip losses reduction at the backside of flanged diffuser. Quantitative data showed flow performance in interior diffuser with top increased velocity augmentation of flanged diffuser is angle 900 by 9,82 m/s or 1,96 times freestream velocities and static pressure coefficient value by -2.85

Fotodegradasi Zat Pewarna Tekstil (Rhodamin B) Menggunakan Adsorben Berbasis Material Komposit Kalsium Titanate (Catio3)

Komposit nanopartikel kalsium titanate (CaTiO3) berhasil disintesis melalui metode solid-state dan proses kalsinasi menggunakan kalsium karbonat (CaCO3) dan titanium oksida (TiO2) anatase. Bahan awal ditetapkan dalam perbandingan molar CaCO3/TiO2 yakni (1:1), (1:5), dan (1:7). Kedua bahan campuran CaCO3 dan TiO2 dilarutkan dan dihomogenkan melalui pengadukan. Campuran larutan yang telah homogen, diendapkan, dikeringkan dan dikalsinasi menggunakan suhu 900oC. Morfologi dan sifat mikro struktural dari bahan CaTiO3 dikarakterisasi menggunakan scanning electron microscopy (SEM) dan analisis energy dispersive X-ray (EDX). Komposit nanopartikel CaTiO3 selanjutnya digunakan untuk fotodegradasi zat pewarna Rhodamine B (RhB) di bawah sinar lampu UV. Hasil investigasi menunjukkan bahwa mekanisme penyerapan (adsorbsi) RhB dan sifat fotokatalitik dari CaTiO3 sangat tergantung pada komposisi bahan awal. Studi kinetika menunjukkan bahwa aktivitas fotokatalitik reaksi CaTiO3 terhadap RhB mengikuti model kinetika orde pertama. Lebih lanjut, 100mg RhB dapat terdegradasi sebesar 97.37% 23.34% pada penggunaan komposisi CaTiO3 sebanyak 0.5 hingga 2.0g dalam waktu 40menit. Hasil penelitian menunjukkan bahwa fotokatalis berbasis komposit CaTiO3 sangat efektif dalam mendegradasi zat pewarna RhB. Hal ini dikaitkan dengan besarnya luas permukaan aktif katalis serta kemampuan menghasilkan ion radikal pendegradasi RhB dari proses pemisahan muatan

New approaches in component design for dye-sensitized solar cells

Abstract The present perspective presents a number of issues related to the current direction of DSSC research, with emphasis on the transition from iodide-containing electrolyte to charge-transport media (CTMs), electrolytes or solid-state conductors based on inorganic coordination complexes, aiming to attain a better light-to-electricity conversion efficiency, associated with larger photovoltage, and long-term stability. Such a change necessitates the concomitant introduction of novel dyes and counter electrodes. The first part of the perspective introduces an overview of the DSSC field and a number of considerations related to the transition from the triiodide/iodide-based CTM to CTMs based on alternative systems. Subsequently, the recent developments of CTM based on Cu coordination complexes are discussed, from the inorganic physical chemistry point of view, including some highlights about novel dyes associated to these CTMs. Finally, several preparation methods and applications of different types of novel carbonaceous counter electrode substrates, related to the application of the aforementioned novel CTMs, are presented