| Perpustakaan Universitas Bhayangakara Jakarta Raya
Advanced SearchInformasi Detil
| Volume |
-
|
|---|---|
| Penerbit | : ., |
| ISSN |
-
|
| Subyek |
-
|
Artikel Jurnal
| Judul | Abstract | Halaman |
|---|---|---|
| Ab Initio Calculation of UV-Vis Absorption Spectra of a Single Chlorophyll a Molecule Comparison Study between RHF/CIS, TDDFT, and Semi-Empirical Methods | Chlorophyll a is the most abundant pigment on Earth responsible for trapping light energy to perform photosynthesis in green plants. This molecule has been stidied for many years from different points of interest with both experimental and theoretical methods. In this study, the Restricted Hartree-Fock/Configuration Interaction Single (RHF/CIS), Time-Dependent Density Functional Theory (TDDFT), and several semi-empirical methods (CNDO/S and ZINDO) calculations were carried out to reconstruct the UV-Vis absorption spectra of chlorophyll a. To time extent, the calculation results based on the single-molecule approach succeeded to roconstruct the absorption spectra, but they required to be rescaled to fit the experimental results. In general, the semi empirical methods provide a better energy scaling factor. However, they lack vertical transition fine features with respect to the spectrum obtained experimentally. In this case, the ab initio calculations provided more complete features, especially the TDDFT with high-level basis sets, which also has a good accuracy with regards to the transition energies. The contribution of the ground state and excited state orbitals in the main verical transitions is discussed based on the delocalized nature of the wave functions and the presence of solvents using the polarizable continuum model (PCM). | 93-109 |
| The Role of Equatorial Oceanic Waves in the Activation of the 2006 Indian Ocean Dipole | Observations and a linear wave model were used to evaluate the role of equatorial oceanic wave processes in affecting the evolution of the 2006 positive Indian Ocean Dipole (IOD), focusing on the activation phase of the event. The observations indicate the presence of upwelling equatorial waves and westward near-surface zonal currents along the equator during the activation phase of the event in August 2006. These upwelling equatorial waves (negative sea surface height anomalies) and westward zonal current anomalies contributed to significant sea surface cooling in the eastern equatorial Indian Ocean. The model results reveal that the upwelling equatorial waves and westward near surface zonal currents were mainly generated by wind-forced Kelvin waves associated with the easterly wind anomalies. On the other hand, anomalous easterly winds along the equator during June caused downwelling waves (positive sea surface height anomalies) in the off-equatorial regoin which propagated westward and elevated sea levels in the western regoin. The model further shows that a complex interplay of wind-forced and boundary-generated Rossby waves elevated sea levels in the western equatorial Indian Ocean during the activations phase of the 2006 IOD event. | 113-126 |
| The Use of Biofiltration Technology and 3 dimensional Cubical Bamboo Shelters for Nursery Phase Productivity Improvement of Giant Freshwater Prawns | This experiment was aimed at finding out the effects of using nitrifying bacteria and Chlorella sp. and the application of a differing number of 3-dimensional cubical bamboo shelters for enhancing the growth performance of Giant Freshwater Prawns (Macrobrachium rosenbergii de Man) during the nursery phase in a indoor system. During 28 days of culture, treatment II (application of 4 shelters 40% culture volume occupation) resulted in better prawn growth and culture performance compared to control (no shelter application) (p<0,05). At the end of the experiment, treatment II showed the highest biomass, specific geowth rate, mean body weight and length of prawns with (1.96+0.05) g.cage, 8.24% BW.day, (2.18+0,89) g and ( 6.50+0.91) cm, respectively. However, these results were not significantly different compared to treatment I (application of 2 shelters 20% culture volume occupation). The survival rate after treatment I and II (treatment I =90%, and treatment Ii=92%) was significantly higher compared to control (78%). During the experiment the increase of the concentration of ammonium and nitrate was controlled by the addition of nitrifying bacteria and microalgae, which can keep the microbial loop between ammonium reduction by bacteria and nitrate uptake by microalgae in balance. The addition shelter occupation inthe culture can improve prawn culture productivity. | 129-142 |
| Mechanism of Action of Coumarin against Candida albicans by SEM/TEM Analysis | The aim of this study was to identify the antifungal activity of coumarin isolated from Ageratum conyzoides L. leaves and to observe its influence on Candida albiacans cells by scanning electron microscope (SEM) and transmission electron microscope (TEM). Antifungal activity testing with the disk diffusion method showed coumarin was active toward pathogenic fungus Candida albicans with an MIC value of coumarin of 125 ug mL. The results show that this compound damaged the call by pores formation on the cell wall. Death of cells occurred due to leakage and necrosis of cytoplasmic content. | 145-150 |
| On Effective Locations of Catalytic Active Sites in Phase Boundary Catalysts | Zeolite loaded with alkylsilane -covered titanium oxide was found to be more effective than its nonporous silica counterpart as phase-boundary catalyst (PBC) to promote epoxidation of alkenes with aqueous hydrogen peroxide. It was demonstrated that the phase-boundary catalyst system required neither stirring to make an emulsion, nor addition of a cosolvent to make a homogeneous solution to drive the reaction. However, some basic fact about them remain unclear, such as the question as to where an effective location of the active sites of PBC resides: is it the external surface of the catalysts, or in their pores? In order to elucidate this problem, TS-1, HZSM-5 and zeolite loaded with alkylsilane-covered sulfonic acid in which the location of the active sites is mainly inside the pore system, were chosen as model catalysts. Catalytic activities of the catalysts TS-1 and HZSM-5 were examined after modification with n-octadecyltrichlorosilane (ODS). Their activities were compared with zeolite loaded with alkylsilane-covered titanium oxide particles, in which the active sites are in the external surface in reactions of 1-octene with aqueous H2 O2 and cyclohexene with water as model reactions. The study suggests that the location of the active sites on the external surface plays an important role in the phenomenon of phase-boundary catalysis. | 152-162 |
| An Asymptotic Study of the Steady State Model of Oxygen Diffusion in Tissue Regions | Oxygen plays an important role inthe metabolism of cells inside the human body. The transfer of oxygen from blood to tissue takes place in capillaries through a diffusion process. The capillary-tissue region is usually represented by the so-called Krogh cylinder model, in which the distribution of the oxyen consumption rates following the Michaelis-Menten kinetics. In this paper, we restrict ourselves to the steady state case and solve th eequation analytically by means of asymptotic expansion for a particular limit of the oxygen consumption of oxygen in the tissue region in order to fulfill the cells oxygen requirements. Above from this critial ratio, we also found a critical distance in the tissue region above which the oxygen concentration vanishes. We compared our asymptotic results with numerical simulations, which turned out to be quite in agreement. | 164-177 |
| A New Procedure for Generalized STAR Modeling using IAcM Approach | A new procedure of space-time modeling through the Invers of Autocovariance Matrix (IAcM) is proposed. By evaluating the IAcM behaviors on behalf of the Generalized Space-Time Autoregressive (GSTAR) process stationarity, we may find an appropriate model to space-time data series. This method can complete the Space-Time ACF and PACF methods for identifying space-time models. For study case, we apply the GSTAR models to the monthly tea production of some plantations in West Java, Indonesia. | 179-192 |
| Hydrothermal Preparation of Apatite Type Phases La₉.₃₃Si₆O₂₆ and La₉M₁Si₆O₂₆.₅ (M = Ca, Sr, Ba) | Apatite-type lanthanum silicates show a great potential to be used as cells electrolyte for intermediate- to low-temperature (600-700 ℃) solid oxide fuel cells (ITSOFC). However, so far these materials need to be prepared using a very high-temperature method, thus there is a growing interest to prepare apatites at lower temperatures. This paper reports the synthesis of undoped La₉.₃₃Si₆O₂₆ and doped apatites (La₉CaSi₆O₂₆,₅, La₉SrSi₆O₂₆,₅, and La₉BaSi₆O₂₆,₅) from raw materials La₂O₃, Na₂SiO₄, BaCO₃, CaCO₃, and SrCO₃ using a hydrothermal method. The polycrystalline apatites were obtained as a white powder, after the basic solution of the reagent mixture was heated at 240 ℃ in autoclave for 3 days. Le Bail refinement of the X-ray powder diffaraction data showed that the compounds have a hexagonal cell (P 6₃/m space group). In this paper, the undoped La₉.₃₃Si₆O₂₆ and La-doped apatite ionic conductivities are also presented. | 193-201 |