Rhodamine-B dye removal using aliquat-336 modified amberlite XAD-4 resin in fixed-bed columns in series

The present work reports studies on the effective removal of Rhodamine-B (RhB) using Aliquat-336 modified Amberlite XAD-4 resin in the fixed-bed columns in series. The effect of flow rate (Q = 2 to 6 mL·min−1), bed height (h = 3.5 to 7 cm) and initial RhB dye concentration (Cin = 10 to 20 mg·L−1) was studied. When a single column was used, 93% RhB dye was removed in 3 h at Q = 2 mL·min−1, Cin = 10 mg·L−1, and h = 7 cm. When three columns in series were used, almost 100% dye was removed until 80 h. The maximum breakthrough time (142 h) and saturation time (244 h) were found by keeping Q = 2 mL·min−1, h = 7 cm of each column and Cin = 10 mg·L−1. Mathematical modeling of the breakthrough curves was done by using Yoon-Nelson, Clark, Wolborska, and pore diffusion models. The Clark model best fitted the experimental data. The possible interaction mechanism between Aliquat-336 and RhB dye was proposed. The column was regenerated in continuous mode using 1 M HCl solution and maintaining a flow rate of 2 mL·min−1.

The optimal control of the consumer fund with the functions of the insurance company under assumption of the work on the financial market with the advertising strategy

The problem of dynamic system control in the form of the liability fund with the functions of the insurance company working in the financial market and developing the advertising strategy is considered. The generalized Clark model describes the price of risk asset. The optimal controls of the financial market asset portfolio and the part of capital the insurance company spends on the carrying out of the advertising companies were found under which the merit functional takes the largest value. The price of such control also was found.

Fixed bed adsorption treatment of effluent of battery recycling unit to remove Pb(II) using steam-activated granular carbon

Battery recycling generates large amount of effluent which contains the toxic Pb(II) beyond the permissible limit. This effluent was treated for the removal of Pb(II) by fixed bed adsorption onto steam-activated granular carbon. Effect of flow rate, bed diameter and bed height on the performance of fixed bed column was investigated. The experimental data was presented in the form of breakthrough curve. Bed exhaustion time, breakthrough time and adsorbent capacity were determined. The obtained experimental data were evaluated with the four kinetic models: Thomas, Yoon?Nelson, Adams?Bohart and Clark model. The data were fitted well to the Thomas, Yoon?Nelson and Clark model with correlation coefficient R2 > 0.96.

Hydrological Modelling of the Cascina Scala Catchment

This paper presents results about the hydrological modelling of the Cascina Scala catchment. Following a preliminary analysis that proved the Nash cascade of reservoirs superior to the Clark model in the event-based rainfall-runoff simulation for this catchment, a new analysis was carried out to compare two different parameterization approaches applicable in gauged rain events. The former is based on estimating the optimal set of model parameters in each gauged event and then obtaining the ultimate set by averaging the values obtained over the whole group of events; the latter is based on estimating the optimal set of parameters directly on the whole group of gauged events. The results of the analysis proved the better performance of the latter, which enables better representation of the hydrological response of the catchment, evaluated in terms of water discharge pattern at the outlet.

Modeling of drop deformation in proximity to an airfoil

In this paper, an analytical model is improved to predict the shape deformation of a single drop in proximity to an airfoil on the basis of the Clark model. The model was optimized through the adjustment of the viscous force, surface tension force term, and slip velocity. The performance and applicability of the improved model is tested against the published experimental data and discussed. The prediction accuracy is significantly enhanced with the relative error reduced from above 20% to below 5%, almost reaching an equivalent level to the excellent droplet ratio deformation (DRD) model proposed by others previously.

Improved Taylor analogy breakup and Clark models for droplet deformation prediction

The deformation of rain droplet at the leading edge of a wing is critical to the aerodynamic characteristics of the aircraft under heavy rainfall and icing conditions. This study introduces the improvement of the Taylor analogy breakup and Clark models for prediction of droplet deformation near the leading edge of an airfoil. The slip velocity is considered as time-variant in the improved Taylor analogy breakup model. The viscous force is optimized in the improved Clark model. The prediction results suggest that the Clark models predict better results than the Taylor analogy breakup models. Besides, the improved Clark model has the highest prediction accuracy. However, considering the Clark model is derived based on a two-dimensional model, even the improved model still has some unavoidable deviations from the real situation. In addition, the simplified surface area in the surface tension force and the approximation of the pressure force in the original Clark model are very effective, thus are kept the same in the improved Clark model.

OPTIMALISASI PENGATURAN PERIKANAN LEMURU BERDASARKAN MEKANISME SUPPLY DAN DEMAND DI SELAT BALI

Penelitian ini bertujuan untuk menentukan jumlah alat tangkap yang dioperasikan pada perikanan lemuru di Selat Bali, yang didasarkan pada mekanisme keseimbangan supply dan demand. Pendugaan parameter biologi dilakukan menggunakan model CYP, pendugaan kurva supply menggunakan model Clark dan pendugaan kurva demand menggunakan model Salvatore. Hasil analisis menunjukkan bahwa keseimbangan supply dan demand terjadi pada tingkat harga Rp 5.889 dengan jumlah produksi 10.149 ton per tahun. Sementara itu, berdasarkan hasil survei diperoleh data bahwa harga ikan lemuru berkisar antara Rp 1.500 – 2.000 dengan rata-rata jumlah produksi (tahun 1990-2007) 30.254 ton dengan rata-rata upaya penangkapan 16.934 trip per tahun. Pada kondisi Maximum Sustainable Yield diperoleh maksimum jumlah tangkapan adalah 21.418 ton per tahun dengan jumlah upaya penangkapan 8.023 trip per tahun. Jumlah upaya penangkapan ini setara dengan 81 unit purse seine dengan asumsi setiap unit purse seine memiliki 99 trip per tahun. Mengacu kepada jumlah produksi pada kondisi MSY, maka dengan jumlah produksi 10.149 ton per tahun pada kondisi keseimbangan supply dan demand, hanya 38 unit purse seine yang diperlukan di Selat Bali. Kebijakan pembatasan jumlah upaya penangkapan di lokasi tersebut diharapkan mampu memulihkan sumberdaya ikan lemuru, dan dalam jangka panjang eksploitasi dapat dilakukan secara optimal. Tittle: Optimalization of Governing ‘Lemuru’ Fishery Based on the Supply and Demand Mechanism in the Bali Strait.This research aimed to know amount of fishing effort for capturing lemuru in the Bali Strait based on supply demand equilibrium. Biology parameters were estimated by using CYP model, supply curve was estimated using Clark model and demand curve wos estimated using Salvatore model. Results show that supply demand equilibrium is reached at Rp 5,889 of price and 10,149 MT per year of harvest. Based on survey, price of lemuru was around Rp 1,500 – 2,000 with average of harvest (1990-2007) was 30,254 MT per year. At maximum sustainable yield (MSY), maximum harvest were 21,418 MT per year and fishing effort 8,023 trip per year. Fishing effort at MSY were 81 unit purse seine assuming that one unit purse seine operated 99 trips per year. Based on fishing effort and harvested fish at the MSY, with 10,149 ton per years at the equilibrium point of supply and demand of that particular fish, it required 38 units of purse seine in the Bali Strait. Limiting number of fishing effort in the Bali Strait is to be expected by which enabling to recover lemuru required in the long-run optimal exploitation rate of the lemuru.