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Abstrak :
Amonia merupakan senyawa kimia yang disintesis melalui proses Haber-Bosch yang dapat menghasilkan emisi gas CO2 dalam jumlah besar karena dilakukan pada suhu dan tekanan tinggi, sehingga diperlukan teknologi alternatif untuk mensintesis amonia dengan menggunakan energi yang lebih rendah dan ramah lingkungan. Pada penelitian ini dilakukan pengembangan sistem tandem Sel Surya Tersensitisasi Zat Warna Fotoelektrokimia (DSSC-PEC) untuk reaksi reduksi nitrogen (NRR) menjadi amonia. Sel PEC menggunakan TiO2NT/BiVO4 sebagai fotoanoda untuk oksidasi air yang disintesis dengan metode optimasi SILAR selama 20 siklus memberikan photocurrent sebesar 0,352 mA/cm2. Sebagai katoda tempat berlangsungnya reaksi reduksi nitrogen menjadi amonia, digunakan Ti3+/TiO2NT. Sistem PEC digabungkan dengan DSSC berbasis TiO2NT/N719 dengan efisiensi 1,13% sebagai penambah energi dalam reaksi. Menggunakan sistem ini dengan luas area elektroda masing-masing 3 cm2, amonia yang dihasilkan dianalisis dengan menggunakan metode fenat didapatkan sebesar 0,393 µmol dengan efisiensi Solar to Chemical Conversion (SCC) sebesar 0,003%. ......Ammonia is a chemical compound that is synthesized through the Haber-Bosch process which can produce large amounts of CO2 gas emissions because it is carried out at high temperatures and pressures, so an alternative technology is needed to synthesize ammonia that uses less energy and is environmentally friendly. In this research, the development of a Dye-Sensitized Solar Cell Photoelectrochemical tandem system (DSSC-PEC) was carried out for the nitrogen reduction reaction (NRR) into ammonia. PEC cells using TiO2NT/BiVO4 as a photoanode for water oxidation synthesized by the SILAR optimization method for 20 cycles gave a photocurrent of 0.352 mA/cm2. As the cathode where the nitrogen reduction reaction to ammonia takes place, Ti3+/TiO2NT is used. The PEC system is coupled with a DSSC based on TiO2NT/N719 with an efficiency of 1.13% as an energy booster in the reaction. Using this system with an electrode area of 3 cm2, the ammonia produced was analyzed using the phenate method and obtained 0.393 µmol with a Solar to Chemical Conversion (SCC) efficiency of 0.003%.

Abstrak :
The aim of the present study is to build some mathematical models and then to forecast some fertility parameters in urban area of Bangladesh. For this purpose, the secondary time series data on Crude Birth Rate (CBR), Total Fertility Rate (FFR). Gross Reproduction Rate (GRR) and Net Reproduction Rate (NRR) of various issues duly published by Bangladesh Bureau of Statistics (BBS) have been used in the present study. A few mathematical time trend models have been fitted to time series data of CBR, TFR, GRR and NRR It is _found that the CBR follows quadratic H.e. parabolic) polynomial model while the TPR, GRR and NRR follow simple linear regression model. Model validation technique .such as Cross- Validity Prediction Power (C VFP), pi, , is applied to these models to verify how much these models are valid or not. It was found that all these models are more than 95%, 79%, 82%, and 72% stable respectively and their shrinkages are only 0.00739Z 0.032l33. 0. 027916, and 0.0424229, respectively. These rates have been forecasted during 1999-2005 using these time trend models.