Study on the distribution regularity of gas volume in multiphase pump

In order to reduce the phase separation, air plug and turbulence vortex in the multiphase pump. The two-fluid model and the standard k-¦ turbulence model are selected, the distribution regularity of gas phase volume within the multiphase pump is researched using the CFD software about air-liquid two-phase under the different working conditions. The results of the study showed that the gas phase gathers at the rim when the gas-liquid two-phase enter into the impeller inlet, and the gas phase is gradually increased at the rim with the increase of the flow rate, the gas is concentrated in the hub at the second half of the impeller, and the most serious aggregation is the small flow rate condition. When the flow is constant, the gas obviously increases in the guide vane hub with the increase of the gas volume fraction. With the increase of the gas volume fraction, the uniformity of the gas phase in the circumferential direction is deteriorated in the inlet and the middle of impeller, and the lower gas volume fraction region is decreased in the impeller. The results of the study reveal the distribution regularity of gas volume within the multiphase pump, provide the reference basis for the design of the multiphase pump under the higher gas volume fraction

Effect of gas volume fraction on the vortex motion within the oil-gas multiphase pump

In order to research the regular pattern of the vortex within the oil-gas multiphase pump with the gas volume fraction changes, the standard K-epsilon turbulence model is selected, the gas-liquid two-phase flow field within the multiphase pump is calculated by the CFD software under the different gas volume fraction, the regular pattern of the vortex motion within the multiphase pump is analyzed under the different gas volume fraction. The results show that, from the impeller hub to the rim, the vortex in the guide vane is gradually become smaller, the vortex within the impeller is gradually obvious, and with the increase of the gas volume fraction, the flow separation, the backflow and the vortex phenomenon within the impeller and the guide vane are gradually increased. It is also found that the flow separation has a greater influence on the turbulent dissipation within the whole flow field, that is, the more serious the area of off flow, the greater the energy loss. The results provide an important theoretical basis for the optimal design of the structure of oil-gas multiphase pump

Effect of gas volume fraction on vortex motion in hydraulic turbine

In order to analyze the vortex motion in the flow channel of the hydraulic turbine impeller during the gas volume fraction change. Now, the pump with a specific speed of 55.7 is chosen as hydraulic turbine. On the basis of considering the gas compressibility, to take numerical calculation on the model under different flow rates and different gas volume fraction, to analyze the influence of gas volume fraction on vortex motion law in the impeller flow channel. Findings: When the flow rate is small, the relative velocity distribution in the impeller flow channel is uneven, the velocity field is chaotic, and there are obvious vortices, with the increase of the gas volume fraction, the vortices in the impeller flow channel gradually move to the inlet direction of the blade; With the increase of the flow rate, the flow in the channel of the hydraulic turbine impeller is unstable. Both the pressure surface and the suction surface of the blade appear vortices, the vortex region in the impeller flow channel is enlarged, and all of them are concentrated on the back of the blade. The results provide a theoretical basis for the optimal design of hydraulic turbine structures

New, Improved Bulk-microphysical Schemes for Studying Precipitation Processes in WRF

Advances in computing power allow atmospheric prediction models to be mn at progressively finer scales of resolution, using increasingly more sophisticated physical parameterizations and numerical methods. The representation of cloud microphysical processes is a key component of these models, over the past decade both research and operational numerical weather prediction models have started using more complex microphysical schemes that were originally developed for high-resolution cloud-resolving models (CRMs). A recent report to the United States Weather Research Program (USWRP) Science Steering Committee specifically calls for the replacement of implicit cumulus parameterization schemes with explicit bulk schemes in numerical weather prediction (NWP) as part of a community effort to improve quantitative precipitation forecasts (QPF). An improved Goddard bulk microphysical parameterization is implemented into a state-of the-art of next generation of Weather Research and Forecasting (WRF) model. High-resolution model simulations are conducted to examine the impact of microphysical schemes on two different weather events (a midlatitude linear convective system and an Atllan"ic hurricane). The results suggest that microphysics has a major impact on the organization and precipitation processes associated with a summer midlatitude convective line system. The 31CE scheme with a cloud ice-snow-hail configuration led to a better agreement with observation in terms of simulated narrow convective line and rainfall intensity. This is because the 3ICE-hail scheme includes dense ice precipitating (hail) particle with very fast fall speed (over 10 m/s). For an Atlantic hurricane case, varying the microphysical schemes had no significant impact on the track forecast but did affect the intensity (important for air-sea interaction

Differentiation potential of STRO-1+ dental pulp stem cells changes during cell passaging

<p>Abstract</p> <p>Background</p> <p>Dental pulp stem cells (DPSCs) can be driven into odontoblast, osteoblast, and chondrocyte lineages in different inductive media. However, the differentiation potential of naive DPSCs after serial passaging in the routine culture system has not been fully elucidated.</p> <p>Results</p> <p>DPSCs were isolated from human/rat dental pulps by the magnetic activated cell sorting based on STRO-1 expression, cultured and passaged in the conventional culture media. The biological features of STRO-1⁺DPSCs at the 1^stand 9^thpassages were investigated. During the long-term passage, the proliferation ability of human STRO-1⁺DPSCs was downregulated as indicated by the growth kinetics. When compared with STRO-1⁺DPSCs at the 1^stpassage (DPSC-P1), the expression of mature osteoblast-specific genes/proteins (alkaline phosphatase, bone sialoprotein, osterix, and osteopontin), odontoblast-specific gene/protein (dentin sialophosphoprotein and dentin sialoprotein), and chondrocyte-specific gene/protein (type II collagen) was significantly upregulated in human STRO-1⁺DPSCs at the 9^thpassage (DPSC-P9). Furthermore, human DPSC-P9 cells in the mineralization-inducing media presented higher levels of alkaline phosphatase at day 3 and day 7 respectively, and produced more mineralized matrix than DPSC-P9 cells at day 14. <it>In vivo </it>transplantation results showed that rat DPSC-P1 cell pellets developed into dentin, bone and cartilage structures respectively, while DPSC-P9 cells can only generate bone tissues.</p> <p>Conclusions</p> <p>These findings suggest that STRO-1⁺DPSCs consist of several interrelated subpopulations which can spontaneously differentiate into odontoblasts, osteoblasts, and chondrocytes. The differentiation capacity of these DPSCs changes during cell passaging, and DPSCs at the 9^thpassage restrict their differentiation potential to the osteoblast lineage <it>in vivo</it>.</p

5-FU-hydrogel inhibits colorectal peritoneal carcinomatosis and tumor growth in mice

<p>Abstract</p> <p>Background</p> <p>Colorectal peritoneal carcinomatosis (CRPC) is a common form of systemic metastasis of intra-abdominal cancers. Intraperitoneal chemotherapy is a preferable option for colorectal cancer. Here we reported that a new system, 5-FU-loaded hydrogel system, can improve the therapeutic effects of intraperitoneal chemotherapy.</p> <p>Methods</p> <p>A biodegradable PEG-PCL-PEG (PECE) triblock copolymer was successfully synthesized. The biodegradable and temperature sensitive hydrogel was developed to load 5-FU. Methylene blue-loaded hydrogel were also developed for visible observation of the drug release. The effects and toxicity of the 5-FU-hydrogel system were evaluated in a murine CRPC model.</p> <p>Results</p> <p>The hydrogel system is an injectable flowing solution at ambient temperature and forms a non-flowing gel depot at physiological temperature. 5-FU-hydrogel was subsequently injected into abdominal cavity in mice with CT26 cancer cells peritoneal dissemination. The results showed that the hydrogel delivery system prolonged the release of methylene blue; the 5-FU-hydrogel significantly inhibited the peritoneal dissemination and growth of CT26 cells. Furthermore, intraperitoneal administration of the 5-FU-hydrogel was well tolerated and showed less hematologic toxicity.</p> <p>Conclusions</p> <p>Our data indicate that the 5-FU-hydrogel system can be considered as a new strategy for peritoneal carcinomatosis, and the hydrogel may provide a potential delivery system to load different chemotherapeutic drugs for peritoneal carcinomatosis of cancers.</p

Titanium based cranial reconstruction using incremental sheet forming

In this paper, we report recent work in cranial plate manufacturing using incremental sheet forming (ISF) process. With a typical cranial shape, the ISF process was used to manufacture the titanium cranial shape by using different ISF tooling solutions with and without backing plates. Detailed evaluation of the ISF process including material deformation and thinning, geometric accuracy and surface finish was conducted by using a combination of experimental testing and Finite Element (FE) simulation. The results show that satisfactory cranial shape can be achieved with sufficient accuracy and surface finish by using a feature based tool path generation method and new ISF tooling design. The results also demonstrate that the ISF based cranial reconstruction has the potential to achieve considerable lead time reduction as compared to conventional methods for cranial plate manufacturing. This outcome indicates that there is a potential for the ISF process to achieve technological advances and economic benefits as well as improvement to quality of life

In vivo and in vitro tracking of erosion in biodegradable materials using non-invasive fluorescence imaging

Author Manuscript 2012 March 1.The design of erodible biomaterials relies on the ability to program the in vivo retention time, which necessitates real-time monitoring of erosion. However, in vivo performance cannot always be predicted by traditional determination of in vitro erosion[superscript 1, 2] , and standard methods sacrifice samples or animals[superscript 3], preventing sequential measures of the same specimen. We harnessed non-invasive fluorescence imaging to sequentially follow in vivo material-mass loss to model the degradation of materials hydrolytically (PEG:dextran hydrogel) and enzymatically (collagen). Hydrogel erosion rates in vivo and in vitro correlated, enabling the prediction of in vivo erosion of new material formulations from in vitro data. Collagen in vivo erosion was used to infer physiologic in vitro conditions that mimic erosive in vivo environments. This approach enables rapid in vitro screening of materials, and can be extended to simultaneously determine drug release and material erosion from a drug-eluting scaffold, or cell viability and material fate in tissue-engineering formulations.National Institutes of Health (U.S.) (GM/HL 49039)National Institutes of Health (U.S.) (UL1 RR 025758

Autism as a disorder of neural information processing: directions for research and targets for therapy

The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself

Monascus-Fermented Dioscorea Enhances Oxidative Stress Resistance via DAF-16/FOXO in Caenorhabditis elegans

BACKGROUND: Monascus-fermented products are mentioned in an ancient Chinese pharmacopoeia of medicinal food and herbs. Monascus-fermented products offer valuable therapeutic benefits and have been extensively used in East Asia for several centuries. Several biological activities of Monascus-fermented products were recently described, and the extract of Monascus-fermented products showed strong antioxidant activity of scavenging DPPH radicals. To evaluate whether Monascus-fermented dioscorea products have potential as nutritional supplements, Monascus-fermented dioscorea's modulation of oxidative-stress resistance and associated regulatory mechanisms in Caenorhabditis elegans were investigated. PRINCIPAL FINDINGS: We examined oxidative stress resistance of the ethanol extract of red mold dioscorea (RMDE) in C. elegans, and found that RMDE-treated wild-type C. elegans showed an increased survival during juglone-induced oxidative stress compared to untreated controls, whereas the antioxidant phenotype was absent from a daf-16 mutant. In addition, the RMDE reduced the level of intracellular reactive oxygen species in C. elegans. Finally, the RMDE affected the subcellular distribution of the FOXO transcription factor, DAF-16, in C. elegans and induced the expression of the sod-3 antioxidative gene. CONCLUSIONS: These findings suggest that the RMDE acts as an antioxidative stress agent and thus may have potential as a nutritional supplement. Further studies in C. elegans suggest that the antioxidant effect of RMDE is mediated via regulation of the DAF-16/FOXO-dependent pathway