Preparation of Functionalized Hydroxyapatite with Biopolymers as Efficient Adsorbents of Methylene Blue

In this study, we reported the synthesis of hydroxyapatite modified with biopolymers as λ-carrageenan and sodium alginate, which could be used as effective adsorbents of cationic dyes. Evidence of chemical modification was proved through chemical analysis, Fourier Trans-form Infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, and specific surface area. The adsorption process was studied using methylene blue as representative cationic dye. The adsorbed quantity reached, at equilibrium, 142.85 mg/g and 98.23 mg/g using hydroxyapatite-sodium alginate and hydroxyapatite-(λ-carrageenan), respectively. However, it does not exceed 58.8 mg/g in the case of the unmodified hydroxyapatite. The adsorption of methylene blue using hybrid materials complied well with the pseudo-second-order suggesting a chemi-sorption. Freundlich and Langmuir isotherm described well the adsorption mechanism of the hydroxyapatite-(λ-carrageenan) and hydroxyapatite-sodium alginate, respectively. The high capacities of MB removal obtained in this study suggest the potential use of these materials in the treatment from wastewaters.

Preparation, Physical Characterization and Adsorption Properties of Synthesized Co–Ni–Cr Nanocomposites for Highly Effective Removal of Nitrate: Isotherms, Kinetics and Thermodynamic Studies

In the current effort, the Co–Ni–Cr Nanocomposites were synthesized by chemical method and characterized by means of scanning electron micrographs (SEM), X-ray diffraction (XRD), Fourier trans from infra-red (FTIR), and vibration sample magnetization (VSM). In the final step, these nanoparticles were used to study the nitrate removal efficiency from aqueous solution. The effect of important factor including pH, concentration of Nitrate (NO3−) ion, contact time and nanoparticle dose were studied in order to find the optimum adsorption conditions. A maximum of removal of the nitrate was observed at pH 4, initial concentration of 40 mg L−1, amount of nanoparticle of 0.06 g L−1 and contact time 60 min. The adsorption isotherm values were obtained and analyzed using the Langmuir, Frenudlich, Temkin and Dubinin–Radushkevich equations, the Temkin isotherm being the one that showed the best correlation coefficient (R2 = 0.999). In addition to, the adsorption kinetics studied by the pseudo-first-order, pseudo-second-order, Elovich model, Ritchie and intraparticle diffusion models. The experimental data fitted to pseudo-second-order (R2 = 0.999).

Fusion of Satellite Images in Transform Domain

Unique—Image fusion in light of the wavelet and fourier trans-form comes about rich multispectral points of interest yet gives less spatial subtle elements from source images. Wavelet transform performs well at straight highlights yet not at non-direct discontinuities since Wavelets don't utilize the geometric properties of structures. Curvelet transforms defeat such troubles in include rep-resentation. A novel Image fusion rule by means of high pass balance utilizing Local Magnitude Ratio (LMR) in Fast Discrete Curvelet Transforms domain (FDCT) and Discrete wavelet transform (DWT) is characterized. Indian Remote Sensing Geo satellite images are utilized for MS and Pan images. This fusion rule creates HR multispectral image with high spatial resolution. This technique is contrasted and wavelet, Principal Component Analysis (PCA), Fast Discrete Curvelet Transforms domain fusion strategies. Master postured technique spatially performs alternate strategies and results rich multispectral information.

ANALISIS SPEKTRAL DALAM PENENTUAN PERIODISITAS SIKLUS CURAH HUJAN DI WILAYAH SELATAN JATILUHUR, KABUPATEN SUBANG, JAWA BARAT

Rainfall data was studied to know how rainfall in the region has a span of time to form a repetitive pattern. The cycle is a change or a wave up and down within a period and repeated at other periods. The cycle has a frequency that can be completed in one period of time. Fourier transform is an algorithm to convert the time domain X to the domain or the frequency spectrum Y, by breaking the signal into a sinusoidal component. This study used the Fast Fourier Transform (FFT) to find the nature of the trend recurrence of rainfall in the southern region of Jatiluhur Subang. Simulation model was done using monthly rainfall data 1975 - 2012. The results showed a trend of rainfall in the study area was repeated every 12 months (1 cycle). Rainfall prediction was done by using a 5-year rainfall data and used the data observation of the next 5 years as a comparison result predicted to see the performance. Performance prediction was resulted using the Mean Square Error (MSE) used to obtain the difference between the standard derivation calculation of observed data and data modeling. The results of the analysis at the time of validation of the model was MSE 14.92 with a 95% confidence level. FFT used to calculate the value of the error (the difference between the values calculated by the ANN model and observed data) resulted in the change cycle of rainfall occurs over a period of months or approximately 71.68 months or 5-6 years.Keywords: Rain!all, prediction, Fast Fourier Trans!orm (FFT), Mean Square Error (MSE), Subang District ABSTRAKData curah hujan dipelajari salah satunya untuk mengetahui bagaimana curah hujan di suatu wilayah mempunyai rentang waktu untuk membentuk suatu pola berulang. Siklus merupakan suatu perubahan atau gelombang naik dan turun dalam suatu periode serta berulang pada periode lain. Siklus mempunyai frekuensi yang dapat diselesaikan dalam 1 periode waktu. Transformasi Fourier merupakan algoritma untuk mengubah domain waktu X menjadi domain atau spectrum frekuensi Y, dengan cara menguraikan sinyal menjadi komponen sinusoidal. Penelitian ini menggunakan metode Fast Fourier Trans!orm (FFT) untuk mencari sifat berulangnya trend curah hujan di wilayah selatan Jatiluhur Kabupaten Subang. Simulasi model menggunakan data curah hujan bulanan tahun 1975 - 2012. Hasilnya menunjukkan trend curah hujan di lokasi penelitian berulang setiap 12 bulan sekali (1 siklus). Prediksi curah hujan dilakukan dengan menggunakan data curah hujan 5 tahun dan menggunakan observasi data 5 tahun berikutnya sebagai pembanding hasil prediksi untuk melihat performa yang dihasilkan. Performa hasil prediksi menggunakan Mean Square Error (MSE) sebagai standar perhitungan derivasi perbedaaan antara data real dan data pemodelan. Hasil analisis pada saat validasi model didapatkan MSE 14,92 dengan tingkat kepercayaan 95%. Dengan menggunakan analisis FFT untuk menghitung nilai error (perbedaan antara nilai perhitungan model ANN dengan data sebenarnya), diperoleh perubahan siklus curah hujan terjadi dalam kurun waktu 71,68 bulan atau sekitar 5-6 tahun.Kata kunci: Curah hujan, prediksi, Fast Fourier Trans!orm (FFT), Mean Square Error (MSE), Kabupaten Subang

Synthesis and Characterization of Polyaniline Dopd with Anionic Spherical Polyelectrolyte Brushes

The synthesis of polyaniline (PANI) doped with anionic spherical polyelectrolyte brushes (ASPB) (PANI/ASPB nanocomposite) by means of in situ chemical oxidative polymerization were presented. The PANI/ASPB nanocomposite was characterized by Fourier trans-form infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy dispersive x-ray detector (EDX), and Thermo-gravimetric analysis (TGA). Results showed that PANI/ASPB nanocomposite was successfully fabricated with regular morphology. Investigation of the electrical conductivity at room temperature showed that the electrical conductivity of PANI/ASPB nanocomposite was 9.03 S/cm, which was higher than that of PANI (2.7 S/cm). The measurement of dispersity demonstrated that PANI/ASPB nanocomposite had enhanced dispersity in water.

ON THE USE OF DISCRETE FOURIER TRANSFORM FOR SOLVING BIPERIODIC BOUNDARY VALUE PROBLEM OF BIHARMONIC EQUATION IN THE UNIT RECTANGLE

This note is addressed to solving biperiodic boundary value problem of biharmonic equation in the unit rectangle. First, we describe the necessary tools, which is discrete Fourier trans- form for one dimensional periodic sequence, and then extended the results to 2-dimensional biperiodic sequence. Next, we use the discrete Fourier transform 2-dimensional biperiodic sequence to solve discretization of the biperiodic boundary value problem of Biharmonic Equation.

ERROR ESTIMATES FOR A CLASS OF INTEGRAL AND DISCRETE TRANSFORMS

We consider a class of integral transforms which generalize the classical Fourier Trans- form.We erive some theoretical error bounds for the corresponding approximate iscrete transforms,inclu ing the Discrete Fourier Transform.

Notiz: The Microwave Spectrum of the Benzonitrile-Water Complex

We report on the measurement and assignment of the benzonitrile-water complex rotational spectrum in the vi-bronic ground state. This study was facilitated by a newly constructed low frequency molecular beam Fourier trans-form microwave spectrometer.