Characteristic boundary conditions for magnetohydrodynamic equations

In the present study, a characteristic-based boundary condition scheme is developed for the compressible magnetohydrodynamic (MHD) equations in the general curvilinear coordinate system, which is an extension of the characteristic boundary scheme for the Navier-Stokes equations. The eigenstructure and the complete set of characteristic waves are derived for the ideal MHD equations in general curvilinear coordinates $(\xi, \eta, \zeta)$. The characteristic boundary conditions are derived and implemented in a high-order MHD solver where the sixth-order compact scheme is used for the spatial discretization. The fifth-order Weighted Essentially Non-Oscillatory (WENO) scheme is also employed for the spatial discretization of problems with discontinuities. In our MHD solver, the fourth-order Runge-Kutta scheme is utilized for time integration. The characteristic boundary scheme is first verified for the non-magnetic (i.e., $\mathbf{B}=\textbf{0}$) Sod shock tube problem. Then, various in-house test cases are designed to examine the derived MHD characteristic boundary scheme for three different types of boundaries: non-reflecting inlet and outlet, solid wall, and single characteristic wave injection. The numerical examples demonstrate the accuracy and robustness of the MHD characteristic boundary scheme

Safely dissolvable and healable active packaging films based on alginate and pectin

Extensive usage of long-lasting petroleum based plastics for short-lived application such as packaging has raised concerns regarding their role in environmental pollution. In this research, we have developed active, healable, and safely dissolvable alginate-pectin based biocomposites that have potential applications in food packaging. The morphological study revealed the rough surface of these biocomposite films. Tensile properties indicated that the fabricated samples have mechanical properties in the range of commercially available packaging films while possessing excellent healing effciency. Biocomposite films exhibited higher hydrophobicity properties compared to neat alginate films. Thermal analysis indicated that crosslinked biocomposite samples possess higher thermal stability in temperatures below 120 °C, while antibacterial analysis against E. coli and S. aureus revealed the antibacterial properties of the prepared samples against different bacteria. The fabricated biodegradable multi-functional biocomposite films possess various imperative properties, making them ideal for utilization as packaging material

Dental evidence for ontogenetic differences between modern humans and Neanderthals

Humans have an unusual life history, with an early weaning age, long childhood, late first reproduction, short interbirth intervals, and long lifespan. In contrast, great apes wean later, reproduce earlier, and have longer intervals between births. Despite 80 y of speculation, the origins of these developmental patterns in Homo sapiens remain unknown. Because they record daily growth during formation, teeth provide important insights, revealing that australopithecines and early Homo had more rapid ontogenies than recent humans. Dental development in later Homo species has been intensely debated, most notably the issue of whether Neanderthals and H. sapiens differ. Here we apply synchrotron virtual histology to a geographically and temporally diverse sample of Middle Paleolithic juveniles, including Neanderthals, to assess tooth formation and calculate age at death from dental microstructure. We find that most Neanderthal tooth crowns grew more rapidly than modern human teeth, resulting in significantly faster dental maturation. In contrast, Middle Paleolithic H. sapiens juveniles show greater similarity to recent humans. These findings are consistent with recent cranial and molecular evidence for subtle developmental differences between Neanderthals and H. sapiens. When compared with earlier hominin taxa, both Neanderthals and H. sapiens have extended the duration of dental development. This period of dental immaturity is particularly prolonged in modern humans.Human Evolutionary Biolog

Band Engineering of Carbon Nitride Monolayers by N-Type, P-Type, and Isoelectronic Doping for Photocatalytic Applications

Since hydrogen fuel involves the highest energy density among all fuels, production of this gas through the solar water splitting approach has been suggested as a green remedy for greenhouse environmental issues due to extensive consumption of fossil fuels. Low-dimensional materials possessing a large surface-to-volume ratio can be a promising candidate to be used for the photocatalytic approach. Here, we used extensive first-principles calculations to investigate the application of newly fabricated members of two-dimensional carbon nitrides including <i>tg</i>-C₃N₄, <i>hg</i>-C₃N₄, C₂N, and C₃N for water splitting. Band engineering via N-type, P-type, and isoelectronic doping agents such as B, N, P, Si, and Ge was demonstrated for tuning the electronic structure, optimizing solar absorption and band alignment for photocatalysis. Pristine <i>tg</i>-C₃N₄, <i>hg</i>-C₃N₄, and C₂N crystals involve bandgaps of 3.190, 2.772, and 2.465 eV, respectively, which are not proper for water splitting. Among the dopants, Si and Ge dopants can narrow the band gap of carbon nitrides about 0.5–1.0 eV and also increase their optical absorption in the visible spectrum. This study presents the potential for doping with isoelectronic elements to greatly improve the photocatalytic characteristics of carbon nitride nanostructures

Ecological study on the Persian Gulf Martyres Lake, Tehran

The ecological study of the Persian Gulf Martyres Lake carried out at the 5 stations between 2013 and 2014. This study identified 35 phytoplankton taxa. The diatoms taxa was dominated and their abundance recorded highest (2000 000 cell. L^-1) in the lake. The annual phytoplankton abundance was measured as 2500 000 cell. L^-1 during the study. The total nitrogen and water temperature were the significant a biotic parameters to increase cyanophytes abundance. Furthermore, 37 zooplankton taxa were identified. The Rotatoria abundance was dominated zooplankton. The annual zooplankton abundance was measured as 72 ind.l-1. Based on the CCA, there was no correlation between Rotatoria abundance and a biotic parameters. The study benthos showed Ephemeroptera and Diptera abundance were dominated; artificial bottom and lack of sediment and organic matters were the main reasons in decreasing of the benthos density. The Chitgar lake is the poorest lake in Iran due to low density of plankton and benthos organisms. The estimation of fish production was 123 kg/ha and for the lake was determaind 16 tonne. The finding display, invasive species was the main fish Chitgar lake that would be negative effect and increase eutriphication trend in the lake. Phosphorus parameter was limited parameters and trophy level recorded low due to high N/P ration in the lake. In overall the Chitgar lake situation is in Oligotrophic category with the low trophy level

Population structure study of Anzali wetland zooplankton

Anzali wetland is one of the most important places for spawning fishes and zooplankton groups are the first consumer in this ecosystem. They are the perfect food for the larvae of fishes. Zooplankton status was evaluated in 6 stations of different areas of the Anzali wetland during March 2011 to February 2012. Sampling was done by tube (PVC) and passing through of 30 micron planktonic net. The samples were identified and counted by invert microscope. According to the results were identified 60 Genus and 6 phylum (11, 31, 10, 2, 1, 1, 1, 2 genus of phylum Protozoa, Rotatoria, Arthropoda, Gastrotricha, Mollusca, Tardigrada, Nematoda, Porifera, Annelida) respectively. The results showed that the maximum annual average density of zooplankton was observed with 2497 number per liter in Karkan station and the population was more in the summer than in other seasons. Phylum of Rotatoria,, protozoa and superclass Copepoda formed 48, 45 and 6percent of the density respectively. According to the results the population of zooplankton did not change much compared to past studies, excluding Protozoa but the diversity of all zooplankton group are declined very much. According to the statistical analysis Kruskal Wallis are not significant differences between density of zooplankton in different stations, months and seasons (p > 0.05), but significant differences were found in different phylum together (p<0.05)

Comprehensive study on probability of controlling Caspian Sea invasive ctenophora (Mnemiopsis leidyi) (Activity 2: Investigation on Mnemiopsis leidyi diet in the Caspian Sea)

Mnemiopsis leidyi is one the species of comb-jelly. It belongs to the Ctenophore phylum and Lobate order. It is a purely marine, free-swimming animal with a transparent jelly-like walnut-shaped body, which was transported from the Black Sea into Caspian possibly at the end of 1990s. This species is food rival of pelagic fish. It has been reported that the ctenophore caused the dramatic decrease of zooplankton and pelagic fish stock in the Black Sea. In this study, sampling on Mnemiopsis leidyi, zooplankton, phytoplankton was conducted from December 2003 to March 2005, from a total of 11 stations located along four transects (Anzali, Khazarabad, Tourkman and Gorgan Bay) by METU net in the Iranian coasts of the Caspian Sea. Clupeonella catch was done by light fishing with fishing vessel in Anzali region. The results showed that the biomass of M.leidyi had some fluctuation in different seasons and its maximum biomass was recorded in summer with a figure of 524.4±156.2 g.m^2 Tourkman region and the minimum biomass was observed in winter with a figure of 5.15±1.81 g.m^2 in Anzali region. Study of stomach of Mnemiopsis showed, that Acartia (belonged of Copepoda with 66 %), lamlibranchia (13 %) has the highest frequency and the lowest were Balanus nauplii, Rotatoria, Tintinnopsis and Podon polyphemoides. The maximum mean abundance of zooplankton was 29368±24318 n.m3 in winter (Anzali region) and the minimum was recorded 4170±5014 n.m3 in summer (Tourkman region). Copepoda was dominant zooplankton in the Iranian coasts of the Caspian Sea. Chrysophyta with 150000000±440000000 n.m3 and Euglenophyta with 260000±521000 n.m3 had the highest and the lowest frequency respectively in the Caspian Sea. The main foods of Clupeonella were Acartia with 80 %. The survey of stomach of Clupeonella showed that the feeding of these species was not good and the highest fullness index was recorded 220.95±314.67. These results showed, the main food item of Ctenophora and Clupeonella were Copepoda (Acartia). It seems, the impact of Mnemiopsis leidyi feeding has been the important factor in declining zooplankton populations, Clupeonella stocks, and also increasing of phytoplankton abundance

Limnological survey of Anzali Wetland data during 1990-2003 by use of GIS system

Anzali wetland at south west of Caspian located along of North West and southeast and with its unique feature were add on the Ramsar convention list in 1975. There were recorded a high rich of fauna and flora including 276 plant species, 23 reptiles and amphibians, 60 fishes, 26 mammals and 195 birds. Anzali wetland were encountered with numerous disorder with the eutrophication and the early dismissing. The first studies on Anzali wetland started by many international institutions in 1964. In this study the data of biotic and abiotic factors in Anzali wetland analyzed which belongs to different sites (15 to 38 stations) during 1991 to 2000 and were sampled seasonally or monthly in different years. The results showed the increasing trend of phytoplankton abundance from 7.9 to 66 million C./l. and the western part had the most abundant. The Cyanophyta had the most development than other 7 phylum observed in the area. In Anzali wetland identified 143 phytoplankton genus that 9 genus dominated in more than 80 % replicates and 7 genus had the abundance of more than 5 million cell/l. The Zooplankton abundant increased from 580 to 2200 ind./l. The Rotatoria had the most abundant followed by Copepoda. There was identified 104 zooplankton genus that 5 genus were dominated in more than 80 % replicates and 11 genus had the abundance of more than 30 ind./L. The chlorophyll a varied from 8.8 to 50.2 μg/l. and had a increasing trend after 1996, meanwhile it was measured higher than 25 μg/l in most of the stations. The results of benthic study showed that the Chironomidae and Tubificidae were observed more than other organisms which comprised 12.2 to 23.5% of total biomass of benthic organisms in studied period. The range of biomass was 1.1 to 7.8 g/m2. The ichthyologic survey showed presence of 60 species that 11 species were exotic. 28 species belong to freshwater, 17 species were anadromous and 8 species were resident in estuary. The highest and lowest fish catch were 640 and 288 ton in 1994 and 1999 respectively and it was about 500 ton at the end of period. The hydrochemical factors had the various fluctuation so that the nutrients parameters had a significant difference over studied period. Total nitrogen was varied from 0.78 to 1.41 mg/l and total phosphorus varied from 0.05 to 0.1 μg/l.. The oxygen dissolved amount was from 4.6 to 8.7. EC was between 3 to 5 ms/cm during September and October that indicated of Caspian water projection. According to geographic position of station, all biotic and abiotic data, were arranged. The data bank is used by Idrisi software to produce of necessary maps. Analysis of data showed that there must be a responsible department with a vast authority. Conservation and eutrophication prevention of Anzali wetland connect to special attention to catchment area and landuse management of the wetland. Also there is an urgent need for well-developed technologies and managements to reduce the organic pollution and its environmental impacts on the Anzali Lagoon