2,037 research outputs found

    Structural Optimization of an Aeroelastically Tailored Composite Wing

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    Effects of aspect ratio, sweep angle, and stacking sequence of laminated composites were studied to find the optimized configuration of an aeroelastically tailored composite wing idealized as a flat plate in terms of flutter speed. The aeroelastic analysis has been carried out in frequency-domain. The modal approach in conjunction with Doublet-lattice Method (DLM) has been opted for structural and unsteady aerodynamic analysis, respectively. The interpolation between aerodynamic boxes and structural nodes has been done using surface spline. To study the effect of stacking sequence the classical lamination theory (CLT) has been chosen. The parametric studies showed the effective ply orientation angle to be somewhere between 15 and 30 degree, while the plates with lower aspect ratio seems to have higher flutter speed. Forward-swept configurations show higher flutter speed, yet imposed by divergence constraint

    The distribution and diversity of dinoflagellate cysts in sediments of Gwatar Bay (Northeast Gulf of Oman)

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    Most dinoflagellate produce resting cysts during their sexual lifecycle as well as under unfavorable environmental conditions and from water column settle in the sediments substratum. The evaluation of diversity and distribution of dinoflagellate cysts is very important in environmental studies, because cysts act as seed in sea bed that can cause red tide with excystment. This study was performed to determine the diversity and distribution of dinoflagellate cysts in the sediments of Gwatar Bay in 2013 by sediments sampling from five stations. Sediment sampling was made by Ekman grab with covering area of 0.225 square meters with three replicates at each station in two seasons before and after the monsoon. In total of sampling 16 samples in species levels belonging to 9 genera of dinoflagellate cysts were identified. The highest and lowest abundances are related to the genus Protoperidinium (52%) and the genus Zygabikodinium (1%), respectively. The results showed the average dinoflagellate cysts diversity from 2.22 before monsoon have decreased to 2.06 after monsoon

    Morphology and phylogeny of Scrippsiella trochoidea (Dinophyceae) a potentially harmful bloom forming species isolated from the sediments of Iran’s south coast

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    Phytoplankton cells and resting cysts of the species Scrippsiella trochoidea are regular and dominant components of the dinoflagellate flora of coastal marine waters and sediments around the world. This species is a common harmful bloom forming species in coastal waters. In this study, for the first time cyst of S. trochoidea were isolated from the sediments of southeast coast of Iran. Five strains from the germination of a single cyst belonged to S. trochoidea. In order to confirm identification of the species an excystment and encystment experiment, cyst and germinated cell morphology and plate pattern by light and electron microscopy (SEM) have been described. The nucleotide sequences of two highly diverse regions, the rDNA-ITS 1,2 and 5.8S-rDNA have been sequenced for all strains. Homologous sequences from GenBank with five Iranian strains were compared to find their phylogenetic relationship. Both NJ and MP phylogenetic and morphological analysis showed five strains of S. trochoidea from Iran were clustered with previously described S. trochoidea and Calciodinellum levantinum species, and its closest relationship was with Scrippsiella sp. strain with a 1.2-1.4% sequence divergence. Results indicate that molecular studies of rDNA if combined with morphological cyst and vegetative cells could be a valuable approach to identification and taxonomy of calciodinelloideae dinoflagellate

    An ANP application for identifying and prioritizing opportunities and threatens for technology transfer

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    During the past few years, there have been different changes in global market due to fast development of science and technology. These changes have increased competition among all existing companies and it has made it difficult for new rivals to gain market share. This paper tries to identify the opportunities and threats of technology transfer in one of world’s fastest growing gas development regions called Pars Special Economic Energy Zone. The proposed model of this paper first identify important factors influencing both opportunities as well as threats and then uses analytical hierarchy process to rank all factors. The results show that the threats were more important than the existing opportunities and among the most important threats, embargo and sales of oil were the most important ones

    Highly sensitive C-reactive protein levels in Iranian patients with pulmonary complication of sulfur mustard poisoning and its correlation with severity of airway diseases

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    Background: Sulfur mustard (SM) is a chemical warfare agent that can cause serious pulmonary complications. This study was designed to determine serum highly sensitive C-reactive protein (hs-CRP) and evaluate its correlation with lung function parameters in patients with chronic obstructive pulmonary disease (COPD) due to SM poisoning. Methods: Fifty consecutive SM patients with stable COPD and a mean age 46.3 + 9.18 years were enrolled in this cross sectional study. Thirty healthymen were selected as controls. Lung function parameters were evaluated. Serum hs-CRP by immunoturbidometry assay was measured in both the patients and controls. Results: In the case group, the mean forced expiratory volume in one second (FEV1) was 2.14 + 0.76 L (58.98%+17.51% predicted). The mean serum hs-CRP was 9.4+6.78 SD and 3.9+1.92 SDmg/L in the cases and controls, respectively, with significant statistical differences (p < .001). There was negative correlation between the serum hs-CRP and FEV1 levels (p ¼ .01). The serum hs-CRP levels were also correlated with Global Initiative for ChronicObstructive Lung disease (GOLD) stages (r ¼ .45, p < .001). Conclusions:Our findings suggest that the serum hs-CRP level is increased in SM patients with COPD and may have a direct correlation with disease severity. It may then be used as a marker for the severity of COPD in patients with SM poisoning

    Morphology and phylogeny of the sea anemone Stichodactyla haddoni (Cnidaria: Anthozoa: Actiniaria) from Chabahar Bay, Iran

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    Carpet anemones of the genus Stichodactyla are characterized by having no calcium carbonate skeleton, being flattened with rather short tentacles, being exclusively tropical, and being hosts for clown fish species. Most of the species belonging to this genus, however, are often very similar morphologically; thus, identification by external features is rather difficult. In this study, we have described the morphology and phylogenetic affinities of a carpet anemone species collected from Chabahar Bay. Although the Iranian species showed different coloration patterns within the same geographical area, they strongly resemble Stichodactyla haddoni Saville-Kent, 1893 in having short tentacles densely covering the undulated oral disc and white, pointed, recognizable exocoelic tentacles. Comparison of 18S rDNA with other actiniarians revealed that the 2 Iranian species are closely related to Stichodactyla haddoni, Stichodactyla gigantea, and Heteractis magnifica. This is the first record of Stichodactyla haddoni from the south eastern coast of Iran and the northern part of the Sea of Oman

    The first phylogenetic study of Goniobranchus annulatus (Mollusca: Nudibranchia) in subtidal area of Chabahar, Oman Sea, Iran, based on sequence of cytochrome oxidase C subunite I gene

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    Nudibranches are the largest group of Hetrerobranches, (a sub-branch of Opisthobranchia) and are widespread and cosmopolitan species. They vary in shape and colors and occur in all waters from intertidal to deep sea zones and from polar to the tropics regions. Nudibranches are subdivided in two main groups including Anthobranchia and Cladobranchia. In the present study, based on morphology the studied species was identified as Goniobranchus annulatus that belong to Anthrobranchia group. In molecular analysis the sequences of the partial mitochondrial COI gene of Goniobranchus annulatus species from Iran with 15 similar sequences of nudibrnaches from gene bank were compared. Phylogenetic based on Neighbor_joining analyze showed a monophyly relationships between families of nudibranches and also revealed that Goniobranchus vibratus is a sister taxa to the Gonidbranchus annulatus from Iran Goniobranchus annulatus with 100% bootstrap support

    Short communication: The first report of Amphipholis squamata (Delle Chiaje, 1829) (Echinodermata: Ophiuroidea) from Chabahar Bay – northern Oman Sea

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    Amphipholis squamata is an important Ophiuroid species belonging to the family Amphiuridae which is widely used in biotechnological and molecular studies. It is a cosmopolitan species and capable to inhabit a wide variety of habitats except the polar regions, from subtidal zone to the depth of 2000 meters. ... In the present study, Amphipholis squamata was reported for the first time from the subtidal zone of Chabahar Bay in northern part of the Oman Sea. This paper also provides information about the taxonomy and morphology of this group of aquatic taxa dwelling in the marine waters of the Iranian coasts of Chabahar Bay and the Oman Sea
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