196,764 research outputs found
Investigation of the performance of a pilotscale CO2 desorption column using CFD simulations
No full textTechnology Center Mongstad (TCM) is the world’s largest and most flexible test facility for amine based CO2 absorption and desorption. This master thesis is based on an operational problem at TCM where excess liquid loading is experienced at water inlet (from the distributor) to the packing section of a CO2 desorption column. This work is mainly focused on creating a CFD simulation of the stripper while having the geometry and problem of the TCM desorber column in mind for further improvements.
A literature search on CFD simulations on CO2 stripper, absorber and packing has been carried out. A 2D laminar CFD simulation of a CO2 capture stripper has been conducted using volume of fluid (VOF) method by OpenFOAM. The objective of this task is to perform a CFD simulation of a liquid flow distribution at the inlet of the packing area where the packing area is simulated as a porous zone.
The porous media is implemented in the middle of the desorber column where its performance is evaluated by observing the change in pressure in that zone. Illustrations showing the liquid phase distribution and relations to the change of pressure and velocity along y-axis have been simulated and evaluated. A case study on velocity and Darcy value has been conducted to see its result on liquid distribution on the packing area. The velocity ranges between 0.1 [m/s] to 2 [m/s] and the Darcy coefficient of Darcy-Forchheimer equation between 100 to 8.85*1010 (The value evaluates permeability of the liquid to the porous zone). The results on this report do not point any solution for the problem but it gives a base case to work further to solve the problem.
In order to improve the current CFD simulation work, reactingMultiphaseEulerFoam solver can be a better choice for this case. Further creating the geometry of the packing in a CAD software and implementing that geometry into OpenFOAM can give more valid results than using a porous media
Trichomyrmex shakeri Sharaf & Al Dhafer, sp. nov.
No full textTrichomyrmex shakeri Sharaf & Al Dhafer sp. nov. urn:lsid:zoobank.org:act:CBBBD8CB-46EF-4D9E-9BBC-4252822A9206 Fig. 13 A–C Etymology The new species has been named in honor of the late Egyptian writer Mahmoud M. Shaker (1909–1997). Material examined Holotype SAUDI ARABIA: worker, Riyadh, Wadi Hanifa, 24.90˚ N, 46.18˚ E, alt. 814 m, 12 Oct. 2015, Aldhafer et al. leg. (KSMA). Paratypes SAUDI ARABIA: 1 w, same data as the holotype (KSMA); 4 w, Riyadh, Wadi Hanifa, 24.90˚ N, 46.18˚ E, alt. 806 m, 29 Apr. 2015, Aldhafer et al. leg. (1 in CASC: CASENT0922068; 3 in KSMA). Type material is collected by pitfall traps. Description MEASUREMENTS. Holotype, worker. TL 2.07; HL 0.62; HW 0.56; SL 0.48; EL 0.19; ML 0.56; PW 0.31; PTL 0.14; PTW 0.09; PPL 0.08; PPW 0.15; CI 90; EI 34; SI 86. WORKER. TL 1.94–2.33; HL 0.58–0.67; HW 0.52–0.64; SL 0.36–0.48; EL 0.18–0.21; ML 0.53–0.66; PW 0.29–0.34; PTL 0.14–0.18; PTW 0.09–0.13; PPL 0.08–0.15; PPW 0.14–0.18; CI 85–96; EI 31–37; SI 68–86 (n = 5). HEAD. Slightly longer than broad and broader anteriorly than posteriorly, with emarginated posterior margin and feebly convex sides; anterior clypeal margin nearly straight or feebly convex; eyes large (EL 0.31–0.36 × HW), with 11 ommatidia in longest row; scapes when laid back from their insertions surpassing posterior margin of head by about one third of eye length. MESOSOMA. Promesonotum distinctly convex in profile; metanotal groove impressed. PILOSITY. Underside of head with few short straight hairs, not forming a psammophore; cephalic surface and mandibles with sparse short hairs, anterior clypeal margin with a median long hair and two pairs of long hairs on each side; antennae with dense appressed pubescence; mesosoma without hairs except for few sparse appressed pubescence on promesonotum. PETIOLE. With one pair of long, backward directed hairs. POSTPETIOLE. With two pairs; first gastral tergite bare except for few sparse appressed pubescence, the remaining gastral tergites with some long hairs. SCULPTURE. Cephalic surface smooth and shining except posterior margin of head, area in front of eyes and mandibles longitudinally rugulose; promesonotal dorsum faintly irregularly sculptured; mesopleura, propodeum, petiole and postpetiole densely punctulate-reticulate; gaster smooth and shining. COLOUR. Uniform yellow, eyes black, mandibular teeth dark brown. Differential diagnosis Among the Arabian Trichomyrmex species, T. shakeri sp. nov. is a conspicuous species, quickly identified by the uniform yellow colour and the exceptionally larger eyes (EL 0.31–0.36 × HW) compared to other sympatric species. Trichomyrmex shakeri sp. nov. is superficially similar to T. santschii (Forel, 1907) from North Africa (Tunisia) in colour and measurements, but it can be readily separated by the absence of the psammophore, which is well-developed in T. santschii. Ecological and biological notes This species is considered uncommon. Only six workers were collected in 150 pitfall traps run for one year at the type locality, a relatively pristine section of Wadi Hanifa (Fig. 13 D). Other sampling methods (soil sifting, light traps, beating sheets) were not successful in adding more material.Published as part of Mostafa R. Sharaf, Shehzad Salman, Hathal M. Al Dhafer, Shahid A. Akbar, Mahmoud S. Abdel-Dayem & Abdulrahman S. Aldawood, 2016, Taxonomy and distribution of the genus Trichomyrmex Mayr, 1865 (Hymenoptera: Formicidae) in the Arabian Peninsula, with the description of two new species, pp. 1-36 in European Journal of Taxonomy 246 on pages 28-31, DOI: 10.5852/ejt.2016.246, http://zenodo.org/record/19304
Effects of Plant and Animal Natural Products on Mitophagy
No full textMitophagy is a protected cellular process that is essential for autophagic removal of damaged mitochondria and for preservation of a healthy mitochondrial population. In the last years, a particular interest has been devoted in studying the effects of natural compounds on mitophagy. Different natural compounds may modulate mitochondrial oxidative phosphorylation, the production of mitochondrial reactive oxygen species, the expression of mitophagy- and autophagy-related genes, and the activities of transcription factors which regulate the expression of mitochondrial proteins, thereby controlling mitochondrial damage and mitophagy. Remarkably, since mitochondrial function has a crucial role in the pathogenesis of various diseases (e.g., cancer, atherosclerosis, Duchenne muscular dystrophy, diabetes complications, Alzheimer's disease, and hepatic steatosis), these effects might have important therapeutic implications. In this review, preclinical studies investigating the role of different natural compounds in the modulation of mitophagy will be discussed
Curcumin: A naturally occurring autophagy modulator
No full textAutophagy is a self-degradative process that plays a pivotal role in several medical conditions associated with infection, cancer, neurodegeneration, aging, and metabolic disorders. Its interplay with cancer development and treatment resistance is complicated and paramount for drug design since an autophagic response can lead to tumor suppression by enhancing cellular integrity and tumorigenesis by improving tumor cell survival. In addition, autophagy denotes the cellular ability of adapting to stress though it may end up in apoptosis activation when cells are exposed to a very powerful stress. Induction of autophagy is a therapeutic option in cancer and many anticancer drugs have been developed to this aim. Curcumin as a hydrophobic polyphenol compound extracted from the known spice turmeric has different pharmacological effects in both in vitro and in vivo models. Many reports exist reporting that curcumin is capable of triggering autophagy in several cancer cells. In this review, we will focus on how curcumin can target autophagy in different cellular settings that may extend our understanding of new pharmacological agents to overcome relevant diseases
Petrobia (Petrobia) pseudotetranychina Auger & Flechtmann 2009
No full textPetrobia (Petrobia) pseudotetranychina Auger & Flechtmann, 2009 (Fig. 1) The first report of Petrobia (Petrobia) pseudotetranychina Auger & Flechtmann, 2009 (Fig. 1), was from Atriplex sp. in Tunisia. This species was collected from a new host plant, Salsola sp. (Amaranthaceae) in Iran, Ravar, Kerman Province, 31° 12' 59" N, 56° 48' 52" E, 1197 m a.s.l., 3 Nov. 2017. This is the second and the first report of this species from the world and Iran, respectively. Distribution South Tunisian oasis areas (Auger et al. 2009); Iran (this paper). How to cite: Shakeri, Z. & Latifi, M. (2020) First record of Petrobia (Petrobia) pseudotetranychina (Trombidiformes: Tetranychidae) in Asia, with two new host plants for Tetranychidae from Iran. Persian Journal of Acarology, 9(1): 83– 85. New host plants Tetranychus truncatus (Ehara, 1956) was collected on peppermint from Razavi Khorasan, Iran by Sadeghi-Namaghi (2009). In this paper, this species was collected from Capparis spinosa in Kerman province, 30° 54' 14" N, 56° 33' 36" E, 1855 m a.s.l., 3 Nov. 2017. This is the second and the first report of this host plant for tetranychid mites, in the world and Iran, respectively. The first report of Capparis spinosa Linnaeus) Capparaceae) as a host plant was for Tetranychus gladioli Livshits & Mitrofanov, 1980 (Mitrofanov et al. 1978). Oligonychus mangiferus (Rahman & Sapra, 1940) was collected on broad leaf tree, white willow, silver poplar, black locust and mango from Razavi Khorasan, Iran by Arbabi et al. (2002) and Sheikholeslam-Zadeh and Sadeghi (2010). Here, this species was collected on Cydonia oblonga Miller (Rosaceae) from Shahrebabak, Kerman province, 30° 13' 03" N, 55° 03' 02" E, 1943 m a.s.l., 10 July 2017. This is the first report of this host plant for tetranychid mites, in the world.Published as part of Shakeri, Zohreh & Latifi, Malihe, 2020, First record of Petrobia (Petrobia) pseudotetranychina (Trombidiformes: Tetranychidae) in Asia, with two new host plants for Tetranychidae from Iran, pp. 83-85 in Persian Journal of Acarology 9 (1) on pages 83-84, DOI: 10.22073/pja.v9i1.55165, http://zenodo.org/record/375595
Scaling purely elastic instability of strongly shear thinning polymer solutions
No full textFlow of viscoelastic polymer solutions in curved channels exhibits instability caused by the elastic nature of polymers even at low Reynolds numbers. However, scaling of the onset of this purely elastic instability in semidilute polymer solutions has not been previously reported. Here we experimentally investigate the flow of highly elastic polymer solutions above their overlap concentrations using pressure measurements and particle image velocimetry. We demonstrate that the onset of instability can be scaled by including shear dependent rheological properties of the polymer solutions in the nonlinear stability analysis. As a result, a universal criterion as function of normalized polymer concentration is provided for scaling the onset of purely elastic instability in the semidilute regime regardless of the type and molecular weight of the polymer
Cytotoxic and Pro-Apoptotic Activities of Diterpenoids from Zhumeria Majdae
No full textSince the ethylacetate (EtOAc) extract of the roots of Zhumeria majdae had the potent cytotoxic effect (IC50 < 50 mu g/ml) on three cancer cell lines; MCF-7, PC3 and MDA-MB-231, therefore the purpose of this study was the isolation of the responsible cytotoxic compounds from the plant. Isolation of the extract led to the identification of four diterpenoids named as lanugon Q (1), 12,16-dideoxy aegyptinone B (2), 12-deoxy-salvipisone (3) and manool (4). The chemical structures have been determined on the basis of 1D and 2D NMR experiments. Compound 1 is reported for the first time in the plants of the Zhumeria genus. The results of cytotoxic and apoptotic evaluation revealed that compound 2 had a strong cytotoxic effect with the IC50 value of 15.90 mu g/ml against MCF-7 cell lines. The sub-G1 peak in flow cytometry histogram of cells treated with the EtOAc extract and compound 2 showed the induction of apoptosis. Changes in the Bax/Bcl-2 ratio and cleavage of PARP were observed. It is to be noted that owing to the strong cytotoxic effect, the Z. majdae extract could be represented as a therapeutic agent against cancer
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Polycyclic aromatic hydrocarbons (PAHs) in soils around oil refineries; Case study: Erbil and Kirkuk refineries, Iraq- A modelling approach
No full textPurpose: Political tensions in Iraq have made attention to environmental issues not a priority for the authorities. Therefore, the influence of Kirkuk and Erbil refineries on contamination of the surrounding soil by polycyclic aromatic hydrocarbons (PAHs), were studied.
Methods: 25 soil samples were collected and analyzed using high-performance liquid chromatography (HPLC), and their fate and health risk were investigated using Exposure Model for Soil-Organic Fate and Transport (EMSOFT) and the Monte Carlo Simulation (MCS) model.
Results: High ∑PAHs contamination (raged from 212.8 to 12,790.4 ppb), the dominance of pyrogenic sources, and high ecological risk were observed. The mean hazard index values for children (0.043) are higher than those for adults (0.02), while the incremental lifetime carcinogenic risk values for adults (8.50E-4) are greater than those for children (5.27E-4). Pyrene is the significant soil PAH from the depth of 3 cm downwards, while phenanthrene and fluorene are the major constituents of PAHs between the depth of 3 and 10 cm. Also, low molecular weight PAHs significantly decrease in soil layers over the time frame, and maximum PAHs concentrations belong to high molecular weight PAHs over 20 years.
Conclusion: Using an appropriate monitoring system, as well as sound management decisions to reduce the emission of environmental pollution are needed. Also, it seems that the use of constant values for soil physicochemical parameters such as moisture and porosity, despite seasonal variations, may result in uncertainty for fate and transport modelling. Therefore, seasonal sampling and analysis of soil parameters, would be helpful
Control methods of alfalfa witches’ broom phytoplasma disease
No full textAlfalfa witches’ broom (AWB) is the most important alfalfa disease in Iran. The infected plants appear severely stunted, erect
and excessively branched and yellowish. Different methods of AWB disease control were studied in a randomized complete
blocks design at three replications in Ardakan (Yazd province, Iran). The methods were dense planting of alfalfa, use of sorghum
as windbreak and spraying with metasystox-R. The results indicated that sorghum and metasystox-R had no significant effect
on disease control. Only dense planting of alfalfa in the field using twice the usual seed quantity significantly reduced the
disease incidence by 16% compared the control that resulted at the 5% probability level. According to this findings, dense planting
of alfalfa stands is recommended for the prevention of AWB disease in alfalfa farms
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