1,096 research outputs found

    Stabilization of active acetylene by-product via sequestration of co\u3csub\u3e2\u3c/sub\u3e

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    © 2020 Taylor & Francis Group, London, UK. The rising rates of carbide lime waste (CLW), the by-product of acetylene production, cause environmental problems and need for the repurposing of the said material. The high content of calcium in such by-products (60–80%) is the main reason for its utilization in CO2 sequestration. This study focused on using of CLW to form simple, reliable, cost-efficient process, applying direct solid-liquid-gas carbonation reaction, which consists of bubbling CO2 gas through an aqueous slurry of slaked CLW with different solid /water ratios. The experimental conditions were adjusted for maximum carbonation efficiency. Experimental results indicated that CLW has the potential to store CO2 in the form of stable carbonates. Considering the total calcium content, an amount of 0.5833 kg CO2 /kg CLW was achieved. The influence of solid/water ratio on the precipitation of calcium carbonate was investigated using SEM that showed a difference in crystal carbonate sizes and morphologies

    Capacity and delay scaling for broadcast transmission in highly mobile wireless networks

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    We study broadcast capacity and minimum delay scaling laws for highly mobile wireless networks, in which each node has to disseminate or broadcast packets to all other nodes in the network. In particular, we consider a cell partitioned network under the simplifed independent and identically distributed (IID) mobility model, in which each node chooses a new cell at random every time slot. We derive scaling laws for broadcast capacity and minimum delay as a function of the cell size. We propose a simple first-come-firstserve (FCFS) flooding scheme that nearly achieves both capacity and minimum delay scaling. Our results show that high mobility does not improve broadcast capacity, and that both capacity and delay improve with increasing cell sizes. In contrast to what has been speculated in the literature we show that there is (nearly) no tradeoff between capacity and delay. Our analysis makes use of the theory of Markov Evolving Graphs (MEGs) and develops two new bounds on ooding time in MEGs by relaxing the previously required expander property assumption. Keywords: Mobile ad hoc networks, Wireless networks, Broadcast, Throughputdelay tradeoff, Scaling laws, Flooding time, Markov evolving graphNational Science Foundation (U.S.) (Grant CNS-1217048)National Science Foundation (U.S.) (Grant CNS-1713725)National Science Foundation (U.S.) (Grant AST-1547331

    Seminavis aegyptiaca sp. Nov., a new amphoroid diatom species from estuary epilithon of the river–nile damietta branch, Egypt

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    During a recent floristic–taxonomic study on the algal flora, including diatoms, from the estuary of the Damietta Branch of the Nile in Egypt, an interesting epilithic diatom species belonging to the genus Seminavis (Naviculaceae) was collected and investigated using both light and scanning electron microscopy. This new diatom species shares morphologically some taxonomic diagnostic features with other related taxa such as S. insignis, S. robusta, and S. ventricosa. However, it still differs by having ventral central striae that are shorter and more or less straight in the middle of the smaller frustules to be clearly radiate in the larger ones and then become geniculate and only radiate near the poles, the central raphe endings are externally more distantly spaced than in the similar species, the elongate central nodule is internally less prominent, and the areola density is much denser. Therefore, we here describe it as Seminavis aegyptiaca sp. nov. Hydrochemical analyses revealed that S. aegyptiaca commonly inhabits typical marine, with a weak tendency towards brackish water, habitats. It was found to be tolerant to meso–eutrophic, nutrient–enriched conditions, based on the data available on seasonal concentrations of N and P compounds. These findings not only contribute to the inventory of Egyptian diatoms, but also increase our understanding of the autecology and distribution of this relatively poorly–known diatom genus

    Residual and Past Entropies of Concomitants from Lai And Xie Extensions of Case-II of Generalized Order Statistics and its Dual

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    In this article, we consider a new extensions of Morgenstern family is Lai and Xie extensions and discuss their concomitants for case-II of generalized order statistics and case-II of dual generalized order statistics. Additionally, recurrence relation between moments is found for the recommended models. We have also derived the expression for the joint distribution of concomitants for case-II of generalized order statistics and its dual. The residual and past entropies are shown last

    The effect of serum angiotensin II and angiotensin II type 1 receptor gene polymorphism on pediatric lupus nephritis

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    Background: Angiotensin II (Ang II) is found to perpetuate inflammation and visceral damage in systemic lupus erythematosus (SLE). It mediates most of its actions through Ang II receptor type I (AT1) whose gene polymorphism A1166C (CC genotype) seems to have pathogenic effects. Objective: To measure serum Ang II and the frequency of AT1 receptor CC genotype among a group of Egyptian patients with pediatric onset lupus nephritis (pLN). Methods: This is a case-control cross sectional study which included 24 patients with pLN and 24 age and sex-matched healthy subjects as controls. Clinical evaluation and routine laboratory markers for SLE patients were done. SLE disease activity index (SLEDAI) and the British Isles Lupus Assessment Group (BILAG)-2004 renal score were measured. Serum Ang II was measured by enzyme linked immunosorbent assay and detection of ATI receptor CC genotype by polymerase chain reaction were done for both patients and controls. Results: Patients had significantly higher serum Ang II than the controls (p=0.0001). The frequency of AT1 receptor CC genotype was significantly higher among patients as compared to the control group (p=0.008). Both serum Ang II and AT1 receptor CC genotype were comparable between patients with proliferative LN class III and IV and those with LN class II (p>0.05). Serum Ang II did not correlate significantly with SLEDAI or BILAG-renal score (p>0.05). Conclusion: Serum Ang II and AT1 receptor CC genotype seem to have pathogenic role in pLN but with no deleterious effects on the phenotype of LN for further assessment.Keywords: Lupus nephritis; Angiotensin II; Angiotensin II type 1 receptor; Polymorphism; Pediatrics

    Crystal structure of 2-(2-methylphenyl)-1,3-thiazolo[4,5-b]pyridine

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    In the title mol­ecule, C13H10N2S, the dihedral angle between the planes through the non-H atoms of the methylbenzene and thi­azo­lopyridine groups is 36.61 (5)°. In the crystal, the thi­azo­lopyridine groups of inversion-related mol­ecules overlap, with a minimum ring-centroid separation of 3.6721 (9) Å. Furthermore, the methylbenzene groups from neighbouring mol­ecules inter­act edge-to-face at an angle of 71.66 (5)°. In addition, weak C-H... N hydrogen bonds form chains exending along [100]

    Crystal structure of 2,2-dimethyl-N-(pyridin-3-yl)propanamide

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    In the title compound, C10H14N2O, the pyridine ring is inclined to the mean plane of the amide moiety [N-C(=O)C] by 17.60 (8)°. There is an intra­molecular C-H...O hydrogen bond present involving the carbonyl O atom. In the crystal, mol­ecules are linked via N-H...N hydrogen bonds, forming chains propagating along [100]. The tert-butyl group is disordered over two sets of sites with a refined occupancy ratio of 0.758 (12):0.242 (12)

    Crystal structure of 3-amino-2-propylquinazolin-4(3H)-one

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    In the title molecule, C11H13N3O, the propyl group is almost perpendicular to the quinazolin-4(3H)-one mean plane, making a dihedral angle of 88.98 (9)°. In the crystal, molecules related by an inversion centre are paired via π–π overlap, indicated by the short distances of 3.616 (5) and 3.619 (5) Å between the centroids of the aromatic rings of neighbouring molecules. Intermolecular N—H...N and N—H...O hydrogen bonds form R66(30) rings and C(5) chains, respectively, generating a three-dimensional network. Weak C—H...O interactions are also observed

    Crystal structure of 2,2-dimethyl-N-(5-methylpyridin-2-yl)propanamide

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    There are two molecules in the asymmetric unit of the title compound, C11H16N2O. The pyridine rings and amide groups overlap almost perfectly (r.m.s. overlay fit = 0.053 Å), but the tertiary butyl groups have different orientations: in one molecule, one of the methyl C atoms is syn to the amide O atom [O—C—C—C = −0.8 (3)°] and in the other the equivalent torsion angle is 31.0 (2)°. In the crystal, the two independent molecules are linked by a pair of N—H...N hydrogen bonds in the form of an R22(8) loop to form a dimer. A C—H...O interaction connects the dimers into [100] chains
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