164 research outputs found
An Eulerian–Eulerian formulation for erosion modelling: an alternate approach.
Sand is commonly produced besides petroleum fluids and it presents a major erosional hazard leading to pipe failures. Particle erosion is a complex process in which material is removed due to the repeated particle impacts. Conventionally, a CFD flow solver and computationally intensive lagrangian particle tracking sub–routines, known as Eulerian–Lagrangian (E–L) model, along with empirical erosion equations are used to predict the erosion rates. The present work introduces an Eulerian–Eulerian (E–E) approach in which the multiphase granular model resolves the solid phase and obviates the need of particles tracking. Particle–laden turbulent flow across a flow restrictor, based on an experimental study, is chosen for validation. Numerical experiments are done in Simcenter STAR–CCM+. Comparison with the experimental data demonstrate a good agreement and in particular, the E–E model yields reliable predictions of impact wear locations, erosion rates as those of E–L model. A 90° square bend is also simulated and comparison of erosion rates on the concave wall demonstrate that E–E model can be used as an alternate to computationally expensive approaches
On-Chip Structure for Timing Uncertainity Measurement Induced by Noise in Integrated Circuits
Noise such as voltage drop and temperature in integrated circuits can cause significant performance variation and even functional failure in lower technology nodes. In this paper, we propose an on-chip structure that measures the timing uncertainty induced by noise during functional and test operations. The proposed on-chip structure facilitates the speed characterization under various workloads and test conditions. The basic structure is highly scalable and can be tailored for various applications such as silicon validation, monitoring operation condition and validating logic built-in-self-test conditions. Simulation results show that it offers very high measurement resolution in a highly efficient manner
PLY WISE FAILURE ANALYSIS OF MONO LEAF SPRING USING HYBRID C-GFRP COMPOSITES
Composite materials are a better alternative for Leaf spring material in automobiles since they have higher stiffness, high impact energy absorption, lesser stresses and also higher strength to weight ratio. The objective is to study the ply wise failure criteria in the composite leaf springs. Leaf springs are modeled and analyzed using ACP PrePost and studied for failure criteria based on four failure theories which are: maximum stress failure theory, maximum strain failure theory, Tsai-Hill failure theory and Tsai-Wu failure theory. Failure load based on these theories is calculated by conducting a parametric study. To improve the maximum failure load, hybrid composites are designed and analyzed by replacing the top, bottom and center layers of the composite laminate. The four different cross-sections which are analyzed are Eglass/epoxy, HC1, HC2 and HC3. The study shows that replacing the top, bottom and center layers does improve the maximum failure load. Although this introduces higher stresses in the component, the stresses in the Eglass/epoxy material at the same positions from the center of the laminate are reduced. HC3 shows 30.7% increment in failure load by considering only vertical loads and 20.8% increment in failure load by considering vertical, side loads and twist moment simultaneously. There is an agreeable error of 1.44 – 1.65% in the results obtained for deformation and 0.88 – 1.33% for failure load between simulation and theoretical calculations. Mechanical properties of the Eglass/epoxy material are evaluated by conducting tensile test and three-point bending test. Mono leaf spring similar to the dimensions of Maruthi 800 vehicle is made using hand layup method. The load vs deformation results of leaf spring show a good agreement between the experimental and the simulation values
10-[2-(Dimethylamino)ethyl]-9-(4-methoxyphenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydroacridine-1,8(2H,5H)-dione
In the title compound, C28H38N2O3, the central ring of the acridinedione system adopts a boat conformation, while one of the outer rings adopts a half-chair conformation and the conformation of the other outer ring is between a sofa and a half-chair. The acridinedione system is buckled, with an angle of 22.01 (3)°. The crystal packing comprises layers of molecules laid parallel to the ac plane, being reinforced by an intermolecular C—H⋯O interaction
Analgesic activity of Cissus quadrangularis linn with Zingiber officinale rosc in male wistar rats
Background: The global scenario, human beings are using various forms of treatment for relief of pain; among them, medicinal plant products have gained popularity because of its wide range of use and less side effects.Methods: Adult Albino rats of either sex were selected and divided into 5 groups. The Eddy’s hot plate was used and maintained temperature (55±0.5ºC), the animals were placed on the hot plate and the time taken for paw licking or jumping was recorded and considered as nociceptive response. The reaction time was observed on 0, 30, 60, and 90 minute.Results: The hot plate reaction time in sec was collected in the intervals of 0, 30, 60 and 90 minutes in all groups. Reaction times as follows: group III (Cissus quadrangularis Linn.) were 2.18±0.04, 3.13±0.05**, 5.83±0.05**, 5.39±0.04**; Group IV (Zingiber officinale Rosc.) were 2.12±0.03, 4.13±0.04**, 7.43±0.07**, 7.16±0.06**; Group V Cissus quadrangularis Linn+ Zingiber officinale Rosc.) were 2.21±0.75, 4.67±0.98**, 8.15±0.89**, 9.02±0.75**; Group II (Dexamethasone) were 2.14±0.05, 5.53±0.05**, 8.14±0.06**, 10.08±0.10** respectively, Results are presented as mean±SEM, (n=6), *p<0.01, **p<0.05 dunnet test used as compared to control.Conclusions: Present study reveals that, the combination treatment of Zingiber officinale Rosc. + Cissus quadrangularis Linn. has been shown significant analgesic effect. High analgesic effect was observed with combination therapy; the effect was shown same as standard drug dexamethasone
Ascaroside Expression in Caenorhabditis elegans Is Strongly Dependent on Diet and Developmental Stage
Background:
The ascarosides form a family of small molecules that have been isolated from cultures of the nematode Caenorhabditis elegans. They are often referred to as “dauer pheromones” because most of them induce formation of long-lived and highly stress resistant dauer larvae. More recent studies have shown that ascarosides serve additional functions as social signals and mating pheromones. Thus, ascarosides have multiple functions. Until now, it has been generally assumed that ascarosides are constitutively expressed during nematode development.
Methodology/Principal Findings:
Cultures of C. elegans were developmentally synchronized on controlled diets. Ascarosides released into the media, as well as stored internally, were quantified by LC/MS. We found that ascaroside biosynthesis and release were strongly dependent on developmental stage and diet. The male attracting pheromone was verified to be a blend of at least four ascarosides, and peak production of the two most potent mating pheromone components, ascr#3 and asc#8 immediately preceded or coincided with the temporal window for mating. The concentration of ascr#2 increased under starvation conditions and peaked during dauer formation, strongly supporting ascr#2 as the main population density signal (dauer pheromone). After dauer formation, ascaroside production largely ceased and dauer larvae did not release any ascarosides. These findings show that both total ascaroside production and the relative proportions of individual ascarosides strongly correlate with these compounds' stage-specific biological functions.
Conclusions/Significance:
Ascaroside expression changes with development and environmental conditions. This is consistent with multiple functions of these signaling molecules. Knowledge of such differential regulation will make it possible to associate ascaroside production to gene expression profiles (transcript, protein or enzyme activity) and help to determine genetic pathways that control ascaroside biosynthesis. In conjunction with findings from previous studies, our results show that the pheromone system of C. elegans mimics that of insects in many ways, suggesting that pheromone signaling in C. elegans may exhibit functional homology also at the sensory level. In addition, our results provide a strong foundation for future behavioral modeling studies
Development of stable blackgram [Vigna mungo (L.) Hepper] genotypes by deciphering genotype × environment interaction using Eberhart-Russell and AMMI models
The genotype and environment (G × E) interaction is a key area of research for creating stable cultivars as it has a
major impact on crop yield performance. In this study, we examined the stability and adaptability of the seed yields
of elite blackgram genotypes in four Agricultural Research Centers of PJTSAU consisting of diverse environments in
Telangana, India during Rabi 2019-20 using Eberhart-Russell and Additive Main effects and Multiplicative Interaction
(AMMI) models. A combined analysis of variance showed significant differences between the varieties and the
interactions between the varieties and locations for seed yield. Both Eberhart and Russell and AMMI1 model analyses
of G×E interaction identified G1 (LBG-752) as the stable variety with respect to yielding ability suitable for cultivation
under diverse conditions. Environments A, B, and C were found to be ideal environments for genotypes G7, G8, and
G6, respectively, based on AMMI 2. The selected elite varieties based on different stability analyses could be used for
further exploitation for cultivar release
The First Flight of the Marshall Grazing Incidence X-ray Spectrometer (MaGIXS)
The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) sounding rocket
experiment launched on July 30, 2021 from the White Sands Missile Range in New
Mexico. MaGIXS is a unique solar observing telescope developed to capture X-ray
spectral images, in the 6 - 24 Angstrom wavelength range, of coronal active
regions. Its novel design takes advantage of recent technological advances
related to fabricating and optimizing X-ray optical systems as well as
breakthroughs in inversion methodologies necessary to create spectrally pure
maps from overlapping spectral images. MaGIXS is the first instrument of its
kind to provide spatially resolved soft X-ray spectra across a wide field of
view. The plasma diagnostics available in this spectral regime make this
instrument a powerful tool for probing solar coronal heating. This paper
presents details from the first MaGIXS flight, the captured observations, the
data processing and inversion techniques, and the first science results.Comment: 20 pages, 18 figure
Community-based assessment of human rights in a complex humanitarian emergency: the Emergency Assistance Teams-Burma and Cyclone Nargis
<p>Abstract</p> <p>Introduction</p> <p>Cyclone Nargis hit Burma on May 2, 2008, killing over 138,000 and affecting at least 2.4 million people. The Burmese military junta, the State Peace and Development Council (SPDC), initially blocked international aid to storm victims, forcing community-based organizations such as the Emergency Assistance Teams-Burma (EAT) to fill the void, helping with cyclone relief and long-term reconstruction. Recognizing the need for independent monitoring of the human rights situation in cyclone-affected areas, particularly given censorship over storm relief coverage, EAT initiated such documentation efforts.</p> <p>Methods</p> <p>A human rights investigation was conducted to document selected human rights abuses that had initially been reported to volunteers providing relief services in cyclone affected areas. Using participatory research methods and qualitative, semi-structured interviews, EAT volunteers collected 103 testimonies from August 2008 to June 2009; 42 from relief workers and 61 from storm survivors.</p> <p>Results</p> <p>One year after the storm, basic necessities such as food, potable water, and shelter remained insufficient for many, a situation exacerbated by lack of support to help rebuild livelihoods and worsening household debt. This precluded many survivors from being able to access healthcare services, which were inadequate even before Cyclone Nargis. Aid efforts continued to be met with government restrictions and harassment, and relief workers continued to face threats and fear of arrest. Abuses, including land confiscation and misappropriation of aid, were reported during reconstruction, and tight government control over communication and information exchange continued.</p> <p>Conclusions</p> <p>Basic needs of many cyclone survivors in the Irrawaddy Delta remained unmet over a year following Cyclone Nargis. Official impediments to delivery of aid to storm survivors continued, including human rights abrogations experienced by civilians during reconstruction efforts. Such issues remain unaddressed in official assessments conducted in partnership with the SPDC. Private, community-based relief organizations like EAT are well positioned and able to independently assess human rights conditions in response to complex humanitarian emergencies such as Cyclone Nargis; efforts of this nature must be encouraged, particularly in settings where human rights abuses have been documented and censorship is widespread.</p
Rapid Selection and Proliferation of CD133(+) Cells from Cancer Cell Lines: Chemotherapeutic Implications
Cancer stem cells (CSCs) are considered a subset of the bulk tumor responsible for initiating and maintaining the disease. Several surface cellular markers have been recently used to identify CSCs. Among those is CD133, which is expressed by hematopoietic progenitor cells as well as embryonic stem cells and various cancers. We have recently isolated and cultured CD133 positive [CD133(+)] cells from various cancer cell lines using a NASA developed Hydrodynamic Focusing Bioreactor (HFB) (Celdyne, Houston, TX). For comparison, another bioreactor, the rotary cell culture system (RCCS) manufactured by Synthecon (Houston, TX) was used. Both the HFB and the RCCS bioreactors simulate aspects of hypogravity. In our study, the HFB increased CD133(+) cell growth from various cell lines compared to the RCCS vessel and to normal gravity control. We observed a (+)15-fold proliferation of the CD133(+) cellular fraction with cancer cells that were cultured for 7-days at optimized conditions. The RCCS vessel instead yielded a (−)4.8-fold decrease in the CD133(+)cellular fraction respect to the HFB after 7-days of culture. Interestingly, we also found that the hypogravity environment of the HFB greatly sensitized the CD133(+) cancer cells, which are normally resistant to chemo treatment, to become susceptible to various chemotherapeutic agents, paving the way to less toxic and more effective chemotherapeutic treatment in patients. To be able to test the efficacy of cytotoxic agents in vitro prior to their use in clinical setting on cancer cells as well as on cancer stem cells may pave the way to more effective chemotherapeutic strategies in patients. This could be an important advancement in the therapeutic options of oncologic patients, allowing for more targeted and personalized chemotherapy regimens as well as for higher response rates
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