Electric-field-driven polymer entry into asymmetric nanoscale channels

The electric-field-driven entry process of flexible charged polymers such as single stranded DNA (ssDNA) into asymmetric nanoscale channels such as alpha-hemolysin protein channel is studied theoretically and using molecular dynamics simulations. Dependence of the height of the free-energy barrier on the polymer length, the strength of the applied electric field and the channel entrance geometry is investigated. It is shown that the squeezing effect of the driving field on the polymer and the lateral confinement of the polymer before its entry to the channel crucially affect the barrier height and its dependence on the system parameters. The attempt frequency of the polymer for passing the channel is also discussed. Our theoretical and simulation results support each other and describe related data sets of polymer translocation experiments through the alpha-hemolysin protein channel reasonably well

Three-dimensional Brownian diffusion of rod-like macromolecules in the presence of randomly distributed spherical obstacles: Molecular dynamics simulation

Brownian diffusion of rod-like polymers in the presence of randomly distributed spherical obstacles is studied using molecular dynamics (MD) simulations. It is observed that dependence of the reduced diffusion coefficient of these macromolecules on the available volume fraction can be described reasonably by a power law function. Despite the case of obstructed diffusion of flexible polymers in which reduced diffusion coefficient has a weak dependence on the polymer length, this dependence is noticeably strong in the case of rod-like polymers. Diffusion of these macromolecules in the presence of obstacles is observed that is anomalous at short time scales and normal at long times. Duration time of the anomalous diffusion regime is found that increases very rapidly with increasing both the polymer length and the obstructed volume fraction. Dynamics of diffusion of these polymers is observed that crosses over from Rouse to reptation type with increasing the density of obstacles.Comment: 7pages, 6 figures, accepted for publication in JCP, 201

Stock assessment of Huso huso (Linnaeus, 1754) in the south Caspian Sea

We evaluated the stocks of Huso huso in the south Caspian Sea along Iranian coasts using data on different population parameters such as length, age, weight, catch and catch per unit effort changes. The study covered data from 1971 to 2003. The stocks and catch rate of H. huso shows a decrease during the last three decades. The recorded catch for the years 1971-1972 was 74 tons with 5.55kg catch per unit effort which was decreased to 38 tons with 0.26 kg per unit effort in 2003 in gillnet fishery and the same trend was observed in beach seine fishing. The data shows that during 1990 to 2003, the average length of the fish has increased from 192.8 to 216.2 centimeters and the average weight has improved from 73 kg to 116.3 kg. Age frequency comparison between the catch of the years 1990 and 2003 showed that with time, older age classes replaced the younger ones, hence the increase in the length and weight of the fish. Due to the decrease in the younger fish and the increase in illegal fishing, it is anticipated that the fish stocks will suffer a decrease in future

By-catch of sturgeon juveniles in beach seine fishing method in Mazandaran Province, northeast Iran

In an attempt to recognize the harmful fishing times and locations for sturgeons, we used catch statistic to evaluate by-catch of sturgeon juveniles during beach seine fishing over the years 2001-2002 in Mazandaran Province. We found that over the fishing period, 23760 hauls were conducted during which 103000 sturgeons were caught. The highest by-catch occurred in October (37% of the catch) and the lowest occurred in January (5% of the catch). The maximum sturgeon catch per haul was 14.2 in autumn decreasing through the year with 1.26 sturgeon fish caught in each haul in spring. The species composition of the by-catch sturgeon juveniles was determined to be Persian sturgeon (54%), Stellatus sturgeon (37%), Beluga (6%), Russian sturgeon (2%) and Spiny sturgeon (1%)

Analisis Perhitungan Harga Pokok Produksi Dengan Penerapan Metode Full Costing Pada UMKM Kota Banda Aceh

Calculation and acquisition cost of production is strongly Influenced by the application of the method right, so the cost of production is obtained to indicate the actual value occurs. This study conducted on Banda Aceh micro, small and medium enterprises, especially processing businesses of tofu. The purpose of this study is to analyze the production cost price calculation and allocation of costs applied by Banda Aceh micro, small and medium enterprises with the calculation the cost of production using the full costing method. The type of data used in this study is qualitative data which presented in a descriptive or shape description, and quantitative data is presented in the numbers. Sources of data derived from primary data results of interviews conducted with business owners tofu in Banda Aceh, and secondary data obtained from the literature review and other literature that supports the writing of this study. The results indicate that the acquisition cost of production using the full costing method is better in analyzing production costs, its caused the calculation cost of production using the full costing method has included all overhead costs, both fixed and variable during the production process.Keywords— Cost of Production, Full Costing, Process Cos

The study of reproduction, fecundity and diet in 3 species of kilka in the southern part of the Caspian Sea (Bobolsar Region)

Considering the large population of kilka in the Caspian Sea and their role in the survival of ecosystem, it is important to know their biological characteristics as a basic information in the fisheries research activities. The project was conducted to evaluate the biological characteristic of these fishes including: reproduction and fecundity rate, relative frequency percentage, age and weight composition and diet. 1000 fish samples from three different species of Clupeidae 1 - Clupeonella cultriventris (common kilka) 2 - Clupeonella engrauliformis (anchovy) 3 - Clupeonella grimmi (big eye kilka) were studied from November 1993 to November 1994. The study indicates that C. cultriventris starts its spawning in the beginning of spring, C. engrauliformis spawns in the middle of summer and C grimmi has a longer spawning period (once starts in the beginning of autumn and the second period starts at the end of winter). Anchovy has the most relative frequency, the average of absolute fecundity for anchovy and big eye kilka are 32847 ± 10150 and 17892 ± 3916, respectively

Pemanfaatan Bottom Ash Sebagai Bahan Pengganti Pasir Dengan Mutu Beton 28 Mpa

Currently, a lot of coal fuel waste (bottom ash) is produced and dumped / piled up in industrial areas. Handling of coal fuel waste is still limited to stockpiling on vacant land. This is potentially dangerous for the environment and the surrounding community if it is carried into the waters. The point of view of waste coal fuel must be changed, that (bottom ash) is a potential raw material that can be used as a cheap adsorbent. The method used in this test is to make a concrete mixture using SNI 7656:2012 with Bottom Ash as a sand substitution material of 10%, 20%, 30%, and 40%. The concrete that was treated for 7 days, 14 days, and 28 days was then tested to get the compressive strength and density of the concrete. The purpose of this research is to use Bottom Ash as a sand substitute with the aim of getting the compressive strength value of each percentage addition of Bottom Ash, and to determine the effect of Bottom Ash on volume weight, to determine the effect of adding Bottom Ash to the slump test

Investigation of the Effect of Modeling of Control Tunnel in Retaining Structure of J2 Station of Mashhad Metro Using Plaxis 2D

Nowadays using of underground concrete arch excavation method is very common for execution of retaining structures (soldier structure) of deep and semi deep metro stations all around the world. In this method executer can use retaining structure as a part of main structure of station in next construction steps with using of piles of retaining structure as a part of main structure\u27s wall. One of the first steps in building retaining structure of metro station is control tunnel (patrol tunnel) that usually is a prefabricated controlling tunnel in the middle of retaining structure. This tunnel is used for digging bores for concrete piles and arches of retaining structure and will be removed at the end of excavation process. Usually designers don\u27t consider this tunnel in modeling of whole retaining structures in numerical modeling in computer programs like PLAXIS. We have done 2 different modeling of retaining structure of J2 station in Mashhad metro (with and without control tunnel) for considering of the impact of modeling of control tunnel on stresses, deflections, axial forces, bending moments, etc of the model using PLAXIS 8.5 2D. Results and differences between these two kinds of modeling showed that neglecting the patrol tunnel in analyses can cause important reductions in forces and moments of piles and ribs of the retaining structure