WorldWideScience

Sample records for single centrifugation msc

  1. Massively Parallel Single-Molecule Manipulation Using Centrifugal Force

    Science.gov (United States)

    Wong, Wesley; Halvorsen, Ken

    2011-03-01

    Precise manipulation of single molecules has led to remarkable insights in physics, chemistry, biology, and medicine. However, two issues that have impeded the widespread adoption of these techniques are equipment cost and the laborious nature of making measurements one molecule at a time. To meet these challenges, we have developed an approach that enables massively parallel single- molecule force measurements using centrifugal force. This approach is realized in the centrifuge force microscope, an instrument in which objects in an orbiting sample are subjected to a calibration-free, macroscopically uniform force- field while their micro-to-nanoscopic motions are observed. We demonstrate high- throughput single-molecule force spectroscopy with this technique by performing thousands of rupture experiments in parallel, characterizing force-dependent unbinding kinetics of an antibody-antigen pair in minutes rather than days. Currently, we are taking steps to integrate high-resolution detection, fluorescence, temperature control and a greater dynamic range in force. With significant benefits in efficiency, cost, simplicity, and versatility, single-molecule centrifugation has the potential to expand single-molecule experimentation to a wider range of researchers and experimental systems.

  2. Multiplexed single-molecule force spectroscopy using a centrifuge.

    Science.gov (United States)

    Yang, Darren; Ward, Andrew; Halvorsen, Ken; Wong, Wesley P

    2016-03-17

    We present a miniature centrifuge force microscope (CFM) that repurposes a benchtop centrifuge for high-throughput single-molecule experiments with high-resolution particle tracking, a large force range, temperature control and simple push-button operation. Incorporating DNA nanoswitches to enable repeated interrogation by force of single molecular pairs, we demonstrate increased throughput, reliability and the ability to characterize population heterogeneity. We perform spatiotemporally multiplexed experiments to collect 1,863 bond rupture statistics from 538 traceable molecular pairs in a single experiment, and show that 2 populations of DNA zippers can be distinguished using per-molecule statistics to reduce noise.

  3. Repurposing a Benchtop Centrifuge for High-Throughput Single-Molecule Force Spectroscopy.

    Science.gov (United States)

    Yang, Darren; Wong, Wesley P

    2018-01-01

    We present high-throughput single-molecule manipulation using a benchtop centrifuge, overcoming limitations common in other single-molecule approaches such as high cost, low throughput, technical difficulty, and strict infrastructure requirements. An inexpensive and compact Centrifuge Force Microscope (CFM) adapted to a commercial centrifuge enables use by nonspecialists, and integration with DNA nanoswitches facilitates both reliable measurements and repeated molecular interrogation. Here, we provide detailed protocols for constructing the CFM, creating DNA nanoswitch samples, and carrying out single-molecule force measurements.

  4. A wireless centrifuge force microscope (CFM) enables multiplexed single-molecule experiments in a commercial centrifuge.

    Science.gov (United States)

    Hoang, Tony; Patel, Dhruv S; Halvorsen, Ken

    2016-08-01

    The centrifuge force microscope (CFM) was recently introduced as a platform for massively parallel single-molecule manipulation and analysis. Here we developed a low-cost and self-contained CFM module that works directly within a commercial centrifuge, greatly improving accessibility and ease of use. Our instrument incorporates research grade video microscopy, a power source, a computer, and wireless transmission capability to simultaneously monitor many individually tethered microspheres. We validated the instrument by performing single-molecule force shearing of short DNA duplexes. For a 7 bp duplex, we observed over 1000 dissociation events due to force dependent shearing from 2 pN to 12 pN with dissociation times in the range of 10-100 s. We extended the measurement to a 10 bp duplex, applying a 12 pN force clamp and directly observing single-molecule dissociation over an 85 min experiment. Our new CFM module facilitates simple and inexpensive experiments that dramatically improve access to single-molecule analysis.

  5. Evaluation of single and double centrifugation tube methods for concentrating equine platelets.

    Science.gov (United States)

    Argüelles, D; Carmona, J U; Pastor, J; Iborra, A; Viñals, L; Martínez, P; Bach, E; Prades, M

    2006-10-01

    The aim of this study was to evaluate single and double centrifugation tube methods for concentrating equine platelets. Whole blood samples were collected from clinically normal horses and processed by use of single and double centrifugation tube methods to obtain four platelet concentrates (PCs): PC-A, PC-B, PC-C, and PC-D, which were analyzed using a flow cytometry hematology system for hemogram and additional platelet parameters (mean platelet volume, platelet distribution width, mean platelet component concentration, mean platelet component distribution width). Concentrations of transforming growth factor beta 1 (TGF-beta(1)) were determined in all the samples. Platelet concentrations for PC-A, PC-B, PC-C, and PC-D were 45%, 44%, 71%, and 21% higher, respectively, compared to the same values for citrated whole blood samples. TGF-beta(1) concentrations for PC-A, PC-B, PC-C, and PC-D were 38%, 44%, 44%, and 37% higher, respectively, compared to citrated whole blood sample values. In conclusion, the single and double centrifugation tube methods are reliable methods for concentrating equine platelets and for obtaining potentially therapeutic TGF-beta(1) levels.

  6. Single-layer centrifugation through colloid selects improved quality of epididymal cat sperm.

    Science.gov (United States)

    Chatdarong, K; Thuwanut, P; Morrell, J M

    2010-06-01

    The objectives were to determine the: 1) extent of epithelial and red blood cell contamination in epididymal cat sperm samples recovered by the cutting method; 2) efficacy of simple washing, single-layer centrifugation (SLC), and swim-up for selecting epididymal cat sperm; and 3) effects of freezing and thawing on cat sperm selected by various techniques. Ten unit samples were studied; each contained sperm from the cauda epididymides of four cats (total, approximately 200 x 10(6) sperm) and was equally allocated into four treatments: 1) simple washing, 2) single-layer centrifugation through colloid prior to cryopreservation (SLC-PC), 3) single-layer centrifugation through colloid after cryopreservation (SLC-AC), and 4) swim-up. Centrifugation (300 x g for 20 min) was done for all methods. The SLC-PC had a better recovery rate than the SLC-AC and swim-up methods (mean+/-SD of 16.4+/-8.7, 10.7+/-8.9, and 2.3+/-1.7%, respectively; Pblood cell contamination than simple washed samples (0.02+/-0.01, 0.02+/-0.04, 0.03+/-0.04, and 0.44+/-0.22 x 10(6) cells/mL, respectively; P0.05), SLC-PC yielded the highest percentage of sperm with normal midpieces and tails (P0.05). In conclusion, both SLC-PC and swim-up improved the quality of epididymal cat sperm, including better morphology, membrane and DNA integrity, and removal of cellular contamination. However, SLC had a better sperm recovery rate than swim-up. 2010 Elsevier Inc. All rights reserved.

  7. Single-step fabrication of quantum funnels via centrifugal colloidal casting of nanoparticle films

    Science.gov (United States)

    Kim, Jin Young; Adinolfi, Valerio; Sutherland, Brandon R.; Voznyy, Oleksandr; Kwon, S. Joon; Kim, Tae Wu; Kim, Jeongho; Ihee, Hyotcherl; Kemp, Kyle; Adachi, Michael; Yuan, Mingjian; Kramer, Illan; Zhitomirsky, David; Hoogland, Sjoerd; Sargent, Edward H.

    2015-01-01

    Centrifugal casting of composites and ceramics has been widely employed to improve the mechanical and thermal properties of functional materials. This powerful method has yet to be deployed in the context of nanoparticles—yet size–effect tuning of quantum dots is among their most distinctive and application-relevant features. Here we report the first gradient nanoparticle films to be constructed in a single step. By creating a stable colloid of nanoparticles that are capped with electronic-conduction-compatible ligands we were able to leverage centrifugal casting for thin-films devices. This new method, termed centrifugal colloidal casting, is demonstrated to form films in a bandgap-ordered manner with efficient carrier funnelling towards the lowest energy layer. We constructed the first quantum-gradient photodiode to be formed in a single deposition step and, as a result of the gradient-enhanced electric field, experimentally measured the highest normalized detectivity of any colloidal quantum dot photodetector. PMID:26165185

  8. Single-step fabrication of quantum funnels via centrifugal colloidal casting of nanoparticle films.

    KAUST Repository

    Kim, Jin Young; Adinolfi, Valerio; Sutherland, Brandon R; Voznyy, Oleksandr; Kwon, S Joon; Kim, Tae Wu; Kim, Jeongho; Ihee, Hyotcherl; Kemp, Kyle; Adachi, Michael; Yuan, Mingjian; Kramer, Illan; Zhitomirsky, David; Hoogland, Sjoerd; Sargent, Edward H

    2015-01-01

    Centrifugal casting of composites and ceramics has been widely employed to improve the mechanical and thermal properties of functional materials. This powerful method has yet to be deployed in the context of nanoparticles--yet size-effect tuning of quantum dots is among their most distinctive and application-relevant features. Here we report the first gradient nanoparticle films to be constructed in a single step. By creating a stable colloid of nanoparticles that are capped with electronic-conduction-compatible ligands we were able to leverage centrifugal casting for thin-films devices. This new method, termed centrifugal colloidal casting, is demonstrated to form films in a bandgap-ordered manner with efficient carrier funnelling towards the lowest energy layer. We constructed the first quantum-gradient photodiode to be formed in a single deposition step and, as a result of the gradient-enhanced electric field, experimentally measured the highest normalized detectivity of any colloidal quantum dot photodetector.

  9. Single-step fabrication of quantum funnels via centrifugal colloidal casting of nanoparticle films.

    KAUST Repository

    Kim, Jin Young

    2015-07-13

    Centrifugal casting of composites and ceramics has been widely employed to improve the mechanical and thermal properties of functional materials. This powerful method has yet to be deployed in the context of nanoparticles--yet size-effect tuning of quantum dots is among their most distinctive and application-relevant features. Here we report the first gradient nanoparticle films to be constructed in a single step. By creating a stable colloid of nanoparticles that are capped with electronic-conduction-compatible ligands we were able to leverage centrifugal casting for thin-films devices. This new method, termed centrifugal colloidal casting, is demonstrated to form films in a bandgap-ordered manner with efficient carrier funnelling towards the lowest energy layer. We constructed the first quantum-gradient photodiode to be formed in a single deposition step and, as a result of the gradient-enhanced electric field, experimentally measured the highest normalized detectivity of any colloidal quantum dot photodetector.

  10. S. aureus MscL is a pentamer in vivo but of variable stoichiometries in vitro: implications for detergent-solubilized membrane proteins.

    Directory of Open Access Journals (Sweden)

    Michael R Dorwart

    Full Text Available While the bacterial mechanosensitive channel of large conductance (MscL is the best studied biological mechanosensor and serves as a paradigm for how a protein can sense and respond to membrane tension, the simple matter of its oligomeric state has led to debate, with models ranging from tetramers to hexamers. Indeed, two different oligomeric states of the bacterial mechanosensitive channel MscL have been resolved by X-ray crystallography: The M. tuberculosis channel (MtMscL is a pentamer, while the S. aureus protein (SaMscL forms a tetramer. Because several studies suggest that, like MtMscL, the E. coli MscL (EcoMscL is a pentamer, we re-investigated the oligomeric state of SaMscL. To determine the structural organization of MscL in the cell membrane we developed a disulfide-trapping approach. Surprisingly, we found that virtually all SaMscL channels in vivo are pentameric, indicating this as the physiologically relevant and functional oligomeric state. Complementing our in vivo results, we purified SaMscL and assessed its oligomeric state using three independent approaches (sedimentation equilibrium centrifugation, crosslinking, and light scattering and established that SaMscL is a pentamer when solubilized in Triton X-100 and C(8E(5 detergents. However, performing similar experiments on SaMscL solubilized in LDAO, the detergent used in the crystallographic study, confirmed the tetrameric oligomerization resolved by X-ray crystallography. We further demonstrate that this stoichiometric shift is reversible by conventional detergent exchange experiments. Our results firmly establish the pentameric organization of SaMscL in vivo. Furthermore they demonstrate that detergents can alter the subunit stoichiometry of membrane protein complexes in vitro; thus, in vivo assays are necessary to firmly establish a membrane protein's true functionally relevant oligomeric state.

  11. S. aureus MscL is a pentamer in vivo but of variable stoichiometries in vitro: implications for detergent-solubilized membrane proteins.

    Science.gov (United States)

    Dorwart, Michael R; Wray, Robin; Brautigam, Chad A; Jiang, Youxing; Blount, Paul

    2010-12-07

    While the bacterial mechanosensitive channel of large conductance (MscL) is the best studied biological mechanosensor and serves as a paradigm for how a protein can sense and respond to membrane tension, the simple matter of its oligomeric state has led to debate, with models ranging from tetramers to hexamers. Indeed, two different oligomeric states of the bacterial mechanosensitive channel MscL have been resolved by X-ray crystallography: The M. tuberculosis channel (MtMscL) is a pentamer, while the S. aureus protein (SaMscL) forms a tetramer. Because several studies suggest that, like MtMscL, the E. coli MscL (EcoMscL) is a pentamer, we re-investigated the oligomeric state of SaMscL. To determine the structural organization of MscL in the cell membrane we developed a disulfide-trapping approach. Surprisingly, we found that virtually all SaMscL channels in vivo are pentameric, indicating this as the physiologically relevant and functional oligomeric state. Complementing our in vivo results, we purified SaMscL and assessed its oligomeric state using three independent approaches (sedimentation equilibrium centrifugation, crosslinking, and light scattering) and established that SaMscL is a pentamer when solubilized in Triton X-100 and C(8)E(5) detergents. However, performing similar experiments on SaMscL solubilized in LDAO, the detergent used in the crystallographic study, confirmed the tetrameric oligomerization resolved by X-ray crystallography. We further demonstrate that this stoichiometric shift is reversible by conventional detergent exchange experiments. Our results firmly establish the pentameric organization of SaMscL in vivo. Furthermore they demonstrate that detergents can alter the subunit stoichiometry of membrane protein complexes in vitro; thus, in vivo assays are necessary to firmly establish a membrane protein's true functionally relevant oligomeric state.

  12. Comparison of composite rotor blade models: A coupled-beam analysis and an MSC/NASTRAN finite-element model

    Science.gov (United States)

    Hodges, Robert V.; Nixon, Mark W.; Rehfield, Lawrence W.

    1987-01-01

    A methodology was developed for the structural analysis of composite rotor blades. This coupled-beam analysis is relatively simple to use compared with alternative analysis techniques. The beam analysis was developed for thin-wall single-cell rotor structures and includes the effects of elastic coupling. This paper demonstrates the effectiveness of the new composite-beam analysis method through comparison of its results with those of an established baseline analysis technique. The baseline analysis is an MSC/NASTRAN finite-element model built up from anisotropic shell elements. Deformations are compared for three linear static load cases of centrifugal force at design rotor speed, applied torque, and lift for an ideal rotor in hover. A D-spar designed to twist under axial loading is the subject of the analysis. Results indicate the coupled-beam analysis is well within engineering accuracy.

  13. New centrifugation blood culture device.

    Science.gov (United States)

    Dorn, G L; Smith, K

    1978-01-01

    A single-tube blood culture device designed for centrifugation in a tabletop centrifuge is described. Reconstruction experiments using 21 different organisms and human donor blood indicate that excellent recovery can be obtained by centrifugation for 30 min at 3,000 X g. PMID:342539

  14. GMP-compliant isolation and large-scale expansion of bone marrow-derived MSC.

    Directory of Open Access Journals (Sweden)

    Natalie Fekete

    Full Text Available BACKGROUND: Mesenchymal stromal cells (MSC have gained importance in tissue repair, tissue engineering and in immunosupressive therapy during the last years. Due to the limited availability of MSC in the bone marrow, ex vivo amplification prior to clinical application is requisite to obtain therapeutic applicable cell doses. Translation of preclinical into clinical-grade large-scale MSC expansion necessitates precise definition and standardization of all procedural parameters including cell seeding density, culture medium and cultivation devices. While xenogeneic additives such as fetal calf serum are still widely used for cell culture, its use in the clinical context is associated with many risks, such as prion and viral transmission or adverse immunological reactions against xenogeneic components. METHODS AND FINDINGS: We established animal-free expansion protocols using platelet lysate as medium supplement and thereby could confirm its safety and feasibility for large-scale MSC isolation and expansion. Five different GMP-compliant standardized protocols designed for the safe, reliable, efficient and economical isolation and expansion of MSC was performed and MSC obtained were analyzed for differentiation capacity by qPCR and histochemistry. Expression of standard MSC markers as defined by the International Society for Cellular Therapy as well as expression of additional MSC markers and of various chemokine and cytokine receptors was analysed by flow cytometry. Changes of metabolic markers and cytokines in the medium were addressed using the LUMINEX platform. CONCLUSIONS: The five different systems for isolation and expansion of MSC described in this study are all suitable to produce at least 100 millions of MSC, which is commonly regarded as a single clinical dose. Final products are equal according to the minimal criteria for MSC defined by the ISCT. We showed that chemokine and integrin receptors analyzed had the same expression pattern

  15. Cellular Kinetics of Perivascular MSC Precursors

    Directory of Open Access Journals (Sweden)

    William C. W. Chen

    2013-01-01

    Full Text Available Mesenchymal stem/stromal cells (MSCs and MSC-like multipotent stem/progenitor cells have been widely investigated for regenerative medicine and deemed promising in clinical applications. In order to further improve MSC-based stem cell therapeutics, it is important to understand the cellular kinetics and functional roles of MSCs in the dynamic regenerative processes. However, due to the heterogeneous nature of typical MSC cultures, their native identity and anatomical localization in the body have remained unclear, making it difficult to decipher the existence of distinct cell subsets within the MSC entity. Recent studies have shown that several blood-vessel-derived precursor cell populations, purified by flow cytometry from multiple human organs, give rise to bona fide MSCs, suggesting that the vasculature serves as a systemic reservoir of MSC-like stem/progenitor cells. Using individually purified MSC-like precursor cell subsets, we and other researchers have been able to investigate the differential phenotypes and regenerative capacities of these contributing cellular constituents in the MSC pool. In this review, we will discuss the identification and characterization of perivascular MSC precursors, including pericytes and adventitial cells, and focus on their cellular kinetics: cell adhesion, migration, engraftment, homing, and intercellular cross-talk during tissue repair and regeneration.

  16. Mesenchymal stem cell 1 (MSC1-based therapy attenuates tumor growth whereas MSC2-treatment promotes tumor growth and metastasis.

    Directory of Open Access Journals (Sweden)

    Ruth S Waterman

    Full Text Available Currently, there are many promising clinical trials using mesenchymal stem cells (MSCs in cell-based therapies of numerous diseases. Increasingly, however, there is a concern over the use of MSCs because they home to tumors and can support tumor growth and metastasis. For instance, we established that MSCs in the ovarian tumor microenvironment promoted tumor growth and favored angiogenesis. In parallel studies, we also developed a new approach to induce the conventional mixed pool of MSCs into two uniform but distinct phenotypes we termed MSC1 and MSC2.Here we tested the in vitro and in vivo stability of MSC1 and MSC2 phenotypes as well as their effects on tumor growth and spread. In vitro co-culture of MSC1 with various cancer cells diminished growth in colony forming units and tumor spheroid assays, while conventional MSCs or MSC2 co-culture had the opposite effect in these assays. Co-culture of MSC1 and cancer cells also distinctly affected their migration and invasion potential when compared to MSCs or MSC2 treated samples. The expression of bioactive molecules also differed dramatically among these samples. MSC1-based treatment of established tumors in an immune competent model attenuated tumor growth and metastasis in contrast to MSCs- and MSC2-treated animals in which tumor growth and spread was increased. Also, in contrast to these groups, MSC1-therapy led to less ascites accumulation, increased CD45+leukocytes, decreased collagen deposition, and mast cell degranulation.These observations indicate that the MSC1 and MSC2 phenotypes may be convenient tools for the discovery of critical components of the tumor stroma. The continued investigation of these cells may help ensure that cell based-therapy is used safely and effectively in human disease.

  17. Quantification of platelets obtained by different centrifugation protocols in SHR rats

    OpenAIRE

    João Alberto Yazigi Junior; João Baptista Gomes dos Santos; Bruno Rodrigues Xavier; Marcela Fernandes; Sandra Gomes Valente; Vilnei Mattiolli Leite

    2015-01-01

    ABSTRACT OBJECTIVE: To quantify the platelet concentration in the blood of SHR rats, by means of different centrifugation protocols, and to evaluate what the most effective method for obtaining platelets is. METHODS: We used 40 male rats of the isogenic SHR lineage. The animals were divided into three groups: control, using whole blood without centrifugation; single centrifugation, using whole blood subjected to a single centrifugation at 200 × gand 400 × g; and double centrifugation, usin...

  18. Centrifugal separator cascade connected in zigzag manner

    International Nuclear Information System (INIS)

    Kai, Tsunetoshi; Inoue, Yoshiya; Oya, Akio; Nagakura, Masaaki.

    1974-01-01

    Object: To effectively accommodate centrifugal separators of the entire cascade within the available space in a plant by freely selecting perpendicular direction of connection of the centrifugal separator. Structure: Centrifugal separators are connected in zigzag fashion by using a single header for each stage so that in a rectangular shape the entire cascade is arranged. (Kamimura, M.)

  19. Experimental study on enriching 12C by centrifuge method

    International Nuclear Information System (INIS)

    Xiao Huaxian

    1994-07-01

    The diamond made from the highly enriched 12 C, whose thermal conductivity and electric insulativity are much better than that of natural diamond, has widely uses in new and high technology. In many enriching 12 C methods, the gas centrifuge method is superior to others. After selecting the appropriate process gas and solving key problems, such as feed and extract, the separation experiments are performed by a single stage of centrifuge. To increase the separation capacity of single machine, various parameters in the centrifugal separation are optimized, and appropriate mechanical drive, thermal drive, hold-up and process parameters are selected. The optimal operating condition of single machine is also obtained in the cascade. Thus, highly enriched 12 C is produced in the centrifuge cascade

  20. Electrostatics at the membrane define MscL channel mechanosensitivity and kinetics.

    Science.gov (United States)

    Zhong, Dalian; Blount, Paul

    2014-12-01

    The bacterial mechanosensitive channel of large conductance (MscL) serves as a biological emergency release valve, preventing the occurrence of cell lysis caused by acute osmotic stress. Its tractable nature allows it to serve as a paradigm for how a protein can directly sense membrane tension. Although much is known of the importance of the hydrophobicity of specific residues in channel gating, it has remained unclear whether electrostatics at the membrane plays any role. We studied MscL chimeras derived from functionally distinct orthologues: Escherichia coli and Staphylococcus aureus. Dissection of one set led to an observation that changing the charge of a single residue, K101, of E. coli (Ec)-MscL, effects a channel phenotype: when mutated to a negative residue, the channel is less mechanosensitive and has longer open dwell times. Assuming electrostatic interactions, we determined whether they are due to protein-protein or protein-lipid interactions by performing site-directed mutagenesis elsewhere in the protein and reconstituting channels into defined lipids, with and without negative head groups. We found that although both interactions appear to play some role, the primary determinant of the channel phenotype seems to be protein-lipid electrostatics. The data suggest a model for the role of electrostatic interactions in the dynamics of MscL gating. © FASEB.

  1. The c-Met Inhibitor MSC2156119J Effectively Inhibits Tumor Growth in Liver Cancer Models

    Energy Technology Data Exchange (ETDEWEB)

    Bladt, Friedhelm, E-mail: Friedhelm.Bladt@merckgroup.com; Friese-Hamim, Manja; Ihling, Christian; Wilm, Claudia; Blaukat, Andree [EMD Serono, and Merck Serono Research and Development, Merck KGaA, Darmstadt 64293 (Germany)

    2014-08-19

    The mesenchymal-epithelial transition factor (c-Met) is a receptor tyrosine kinase with hepatocyte growth factor (HGF) as its only high-affinity ligand. Aberrant activation of c-Met is associated with many human malignancies, including hepatocellular carcinoma (HCC). We investigated the in vivo antitumor and antimetastatic efficacy of the c-Met inhibitor MSC2156119J (EMD 1214063) in patient-derived tumor explants. BALB/c nude mice were inoculated with MHCC97H cells or with tumor fragments of 10 patient-derived primary liver cancer explants selected according to c-Met/HGF expression levels. MSC2156119J (10, 30, and 100 mg/kg) and sorafenib (50 mg/kg) were administered orally as single-agent treatment or in combination, with vehicle as control. Tumor response, metastases formation, and alpha fetoprotein (AFP) levels were measured. MSC2156119J inhibited tumor growth and induced complete regression in mice bearing subcutaneous and orthotopic MHCC97H tumors. AFP levels were undetectable after 5 weeks of MSC2156119J treatment, and the number of metastatic lung foci was reduced. Primary liver explant models with strong c-Met/HGF activation showed increased responsiveness to MSC2156119J, with MSC2156119J showing similar or superior activity to sorafenib. Tumors characterized by low c-Met expression were less sensitive to MSC2156119J. MSC2156119J was better tolerated than sorafenib, and combination therapy did not improve efficacy. These findings indicate that selective c-Met/HGF inhibition with MSC2156119J is associated with marked regression of c-Met high-expressing tumors, supporting its clinical development as an antitumor treatment for HCC patients with active c-Met signaling.

  2. MSC in clinics: Liver Transplantation

    OpenAIRE

    DETRY, Olivier

    2014-01-01

    For several years, mesenchymal stem cells (MSC) have been evaluated in vivo and in vitro for their immunomodulatory, anti-inflammatory, anti- ischemia-reperfusion injury and “tissue repair” properties. These characteristics could make them interesting in various clinical applications, and particularly in organ transplantation. Taking advantage of our centre expertise and experience concerning MSC use in graft-versus-host disease after bone marrow transplantation and using already functioning ...

  3. Pulling MscL open via N-terminal and TM1 helices: A computational study towards engineering an MscL nanovalve.

    Directory of Open Access Journals (Sweden)

    Adam D Martinac

    Full Text Available There are great opportunities in the manipulation of bacterial mechanosensitive (MS ion channels for specific and targeted drug delivery purposes. Recent research has shown that these ion channels have the potential to be converted into nanovalves through clever use of magnetic nanoparticles and magnetic fields. Using a combination of molecular dynamics (MD simulations and the finite element (FE modelling, this study investigates the theoretical feasibility of opening the MscL channel (MS channel of large conductance of E. coli by applying mechanical force directly to its N-terminus. This region has already been reported to function as a major mechanosensor in this channel. The stress-strain behaviour of each MscL helix was obtained using all atom MD simulations. Using the same method, we simulated two models, the wild-type (WT MscL and the G22N mutant MscL, both embedded in a POPE lipid bilayer. In addition to indicating the main interacting residues at the hydrophobic pore, their pairwise interaction energies were monitored during the channel gating. We implemented these inputs into our FE model of MscL using curve-fitting codes and continuum mechanics equations. In the FE model, the channel could be fully opened via pulling directly on the N-terminus and bottom of TM1 by mutating dominant van der Waals interactions in the channel pore; otherwise the stress generated on the channel protein can irreversibly unravel the N-secondary structure. This is a significant finding suggesting that applying force in this manner is sufficient to open an MscL nanovalve delivering various drugs used, for example, in cancer chemotherapy. More importantly, the FE model indicates that to fully operate an MscL nanovalve by pulling directly on the N-terminus and bottom of TM1, gain-of-function (GOF mutants (e.g., G22N MscL would have to be employed rather than the WT MscL channel.

  4. The finite element analysis program MSC Marc/Mentat a first introduction

    CERN Document Server

    Öchsner, Andreas

    2016-01-01

    Based on simple examples, this book offers a short introduction to the general-purpose finite element program MSC Marc, a specialized program for non-linear problems (implicit solver) distributed by the MSC Software Corporation, which is commonly used in academia and industry. Today the documentation of all finite element programs includes a variety of step-by-step examples of differing complexity, and in addition, all software companies offer professional workshops on different topics. As such, rather than competing with these, the book focuses on providing simple examples, often single-element problems, which can easily be related to the theory that is discussed in finite element lectures. This makes it an ideal companion book to classical introductory courses on the finite element method.

  5. Breaking the hydrophobicity of the MscL pore: insights into a charge-induced gating mechanism.

    Directory of Open Access Journals (Sweden)

    Balasubramanian Chandramouli

    Full Text Available The mechanosensitive channel of large conductance (MscL is a protein that responds to membrane tension by opening a transient pore during osmotic downshock. Due to its large pore size and functional reconstitution into lipid membranes, MscL has been proposed as a promising artificial nanovalve suitable for biotechnological applications. For example, site-specific mutations and tailored chemical modifications have shown how MscL channel gating can be triggered in the absence of tension by introducing charged residues at the hydrophobic pore level. Recently, engineered MscL proteins responsive to stimuli like pH or light have been reported. Inspired by experiments, we present a thorough computational study aiming at describing, with atomistic detail, the artificial gating mechanism and the molecular transport properties of a light-actuated bacterial MscL channel, in which a charge-induced gating mechanism has been enabled through the selective cleavage of photo-sensitive alkylating agents. Properties such as structural transitions, pore dimension, ion flux and selectivity have been carefully analyzed. Besides, the effects of charge on alternative sites of the channel with respect to those already reported have been addressed. Overall, our results provide useful molecular insights into the structural events accompanying the engineered MscL channel gating and the interplay of electrostatic effects, channel opening and permeation properties. In addition, we describe how the experimentally observed ionic current in a single-subunit charged MscL mutant is obtained through a hydrophobicity breaking mechanism involving an asymmetric inter-subunit motion.

  6. Solvent Carryover Characterization and Recovery for a 10-inch Single Stage Centrifugal Contactor

    International Nuclear Information System (INIS)

    Lentsch, R.D.; Stephens, A.B.; Leung, D.T.; Baffling, K.E.; Harmon, H.D.; Suggs, P.C.

    2006-01-01

    A test program has been performed to characterize the organic solvent carryover and recovery from centrifugal contactors in the Caustic-side Solvent Extraction (CSSX) process. CSSX is the baseline design for removing cesium from salt solutions for Department of Energy (DOE) Savannah River Site's Salt Waste Processing Facility. CSSX uses a custom solvent to extract cesium from the salt solution in a series of single stage centrifugal contactors. Meeting the Waste Acceptance Criteria at the Defense Waste Processing Facility and Saltstone, as well as plant economics, dictate that solvent loss should be kept to a minimum. Solvent droplet size distribution in the aqueous outlet streams of the CSSX contactors is of particular importance to the design of solvent recovery equipment. Because insufficient solvent droplet size data existed to form a basis for the recovery system design, DOE funded the CSSX Solvent Carryover Characterization and Recovery Test (SCCRT). This paper presents the droplet size distribution of solvent and concentration in the contactor aqueous outlet streams as a function of rotor speed, bottom plate type, and flow rate. It also presents the performance data of a prototype coalescer. (authors)

  7. Rapid isolation of bone marrow mesenchymal stromal cells using integrated centrifuge-based technology.

    Science.gov (United States)

    Meppelink, Amanda M; Wang, Xing-Hua; Bradica, Gino; Barron, Kathryn; Hiltz, Kathleen; Liu, Xiang-Hong; Goldman, Scott M; Vacanti, Joseph P; Keating, Armand; Hoganson, David M

    2016-06-01

    The use of bone marrow-derived mesenchymal stromal cells (MSCs) in cell-based therapies is currently being developed for a number of diseases. Thus far, the clinical results have been inconclusive and variable, in part because of the variety of cell isolation procedures and culture conditions used in each study. A new isolation technique that streamlines the method of concentration and demands less time and attention could provide clinical and economic advantages compared with current methodologies. In this study, we evaluated the concentrating capability of an integrated centrifuge-based technology compared with standard Ficoll isolation. MSCs were concentrated from bone marrow aspirate using the new device and the Ficoll method. The isolation capabilities of the device and the growth characteristics, secretome production, and differentiation capacity of the derived cells were determined. The new MSC isolation device concentrated the bone marrow in 90 seconds and resulted in a mononuclear cell yield 10-fold higher and with a twofold increase in cell retention compared with Ficoll. The cells isolated using the device were shown to exhibit similar morphology and functional activity as assessed by growth curves and secretome production compared to the Ficoll-isolated cells. The surface marker and trilineage differentiation profile of the device-isolated cells was consistent with the known profile of MSCs. The faster time to isolation and greater cell yield of the integrated centrifuge-based technology may make this an improved approach for MSC isolation from bone marrow aspirates. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  8. Experimental study of multi-component separation by gas centrifuge

    International Nuclear Information System (INIS)

    Zhou, M.S.; Liang, X.W.; Chen, W.N.; Yin, Y.T.

    2006-01-01

    Stable isotopes are applied in many areas and most stable isotopes are multi-component, This paper presents experimental results of several stable isotopes separation conducted in Tsinghua University by using ultra-speed gas centrifuges. Xe, WF 6 , TeF 6 , SiHCl 3 , SiF 4 were chosen as the process gases. By adjusting some of the centrifuge's parameters, the suitable centrifuge parameters for different process gas separations were found and the overall unit separation factors γ 0 were obtained by means of single gas centrifuge separation. The experimental results show that with appropriate process gases, stable isotope separation by gas centrifuge was effective. (authors)

  9. Observations on centrifugation: application to centrifuge development.

    Science.gov (United States)

    Roberts, T; Smith, M; Roberts, B

    1999-11-01

    This report outlines the background to the development of an automated, serial, discrete centrifuge, reporting on the criteria considered essential in such an instrument. We established the criteria by examining the detailed logistics of centrifuge operation in a hospital laboratory. The mean sample load per run, using six centrifuges, was 13.6 samples, and the user-selectable cycle time ranged from 00:01:10 to 00:12:33 (hours:minutes:seconds) with a fixed g value of 1050. During the laboratory working window, (0900-1700), only 50% of the centrifuge capacity was utilized and more than one-third of the sample workload was delayed for >5 min because the centrifuges were not emptied promptly. In addition, 35% of the sample workload was centrifuged for less than the time prescribed in the operational specifications. Based on these findings, we designed a new continuous, serial centrifuge to overcome some of the deficiencies noted in the logistics study. The centrifuge operates continuously, nominally treating 150 samples/h, with a cycle time of 5 min at 1,000 g. The cycle time and g value are variable between limits, and their selection governs the throughput rate. Each sample is centrifuged separately in individual rotors mounted in a sturdy carousel with a periphery that traverses a load/unload station. There is no sample delay because of operator absence, and the capacity is fully utilized. The centrifuge can operate in a stand-alone capacity or has the capability of being integrated into a sample preparation system or as a direct front end for high-throughput analyzers.

  10. Student performance in a newly developed MSc programme

    DEFF Research Database (Denmark)

    Richelsen, Ann Bettina

    2011-01-01

    The Technical University of Denmark (DTU) offers, as a consequence of the Bologna Declaration, international Master of Science in Engineering (MSc) programmes. Thereby, one of the challenges for DTU is to evaluate international applicants with an educational engineering background and traditions...... other than DTUs and allow qualified students to enter the MSc programmes. The focus of the present work is a comparison of how international and Danish students perform within specific modules of the MSc curriculum in Engineering Design and Applied Mechanics at Technical University of Denmark...

  11. CENTRIFUGE APPARATUS

    Science.gov (United States)

    Skarstrom, C.; Urey, H.C.; Cohen, K.

    1960-08-01

    A high-speed centrifuge for the separation of gaseous isotopes is designed comprising a centrifugal pump mounted on the outlet of a centrifuge bowl and arranged to pump the heavy and light fractions out of the centrifuge bowl in two separate streams.

  12. TACT: A Set of MSC/PATRAN- and MSC/NASTRAN- based Modal Correlation Tools

    Science.gov (United States)

    Marlowe, Jill M.; Dixon, Genevieve D.

    1998-01-01

    This paper describes the functionality and demonstrates the utility of the Test Analysis Correlation Tools (TACT), a suite of MSC/PATRAN Command Language (PCL) tools which automate the process of correlating finite element models to modal survey test data. The initial release of TACT provides a basic yet complete set of tools for performing correlation totally inside the PATRAN/NASTRAN environment. Features include a step-by-step menu structure, pre-test accelerometer set evaluation and selection, analysis and test result export/import in Universal File Format, calculation of frequency percent difference and cross-orthogonality correlation results using NASTRAN, creation and manipulation of mode pairs, and five different ways of viewing synchronized animations of analysis and test modal results. For the PATRAN-based analyst, TACT eliminates the repetitive, time-consuming and error-prone steps associated with transferring finite element data to a third-party modal correlation package, which allows the analyst to spend more time on the more challenging task of model updating. The usefulness of this software is presented using a case history, the correlation for a NASA Langley Research Center (LaRC) low aspect ratio research wind tunnel model. To demonstrate the improvements that TACT offers the MSC/PATRAN- and MSC/DIASTRAN- based structural analysis community, a comparison of the modal correlation process using TACT within PATRAN versus external third-party modal correlation packages is presented.

  13. The histopathology of a human mesenchymal stem cell experimental tumor model: support for an hMSC origin for Ewing's sarcoma?

    DEFF Research Database (Denmark)

    Burns, J S; Abdallah, B M; Schrøder, Henrik Daa

    2008-01-01

    -forming potential of early passage hMSC-TERT20 cells, tumors derived from late passage cells expressed early biomarkers of osteogenesis. However, hMSC-TERT20 cells were heterogeneous for alpha smooth muscle actin (ASMA) expression and one out of six hMSC-TERT20 derived single cell clones was strongly ASMA positive....... Tumors from this ASMA+ clone had distinctive vascular qualities with hot spots of high CD34+ murine endothelial cell density, together with CD34- regions with a branching periodic acid Schiff reaction pattern. Such clone-specific differences in host vascular response provide novel models to explore...

  14. Quantification of platelets obtained by different centrifugation protocols in SHR rats

    Directory of Open Access Journals (Sweden)

    João Alberto Yazigi Junior

    2015-12-01

    Full Text Available ABSTRACT OBJECTIVE: To quantify the platelet concentration in the blood of SHR rats, by means of different centrifugation protocols, and to evaluate what the most effective method for obtaining platelets is. METHODS: We used 40 male rats of the isogenic SHR lineage. The animals were divided into three groups: control, using whole blood without centrifugation; single centrifugation, using whole blood subjected to a single centrifugation at 200 × gand 400 × g; and double centrifugation, using whole blood subjected one centrifugation at different rotations, followed by collection of whole plasma subjected to another centrifugation at different rotations: 200 × g+ 200 ×g; 200 × g+ 400 × g; 200 × g+ 800 × g; 400 ×g+ 400 × g; 400 × g+ 800 × g. Samples of 3 ml of blood were drawn from each animal by means of cardiac puncture. The blood was stored in Vacutainer collection tubes containing 3.2% sodium citrate. The blood from the control group animals was analyzed without being subjected to centrifugation. After the blood from the other groups of animals had been subjected to centrifugation, the whole plasma was collected and subjected to platelet counting in the lower third of the sample. RESULTS: We obtained greatest platelet enrichment in the subgroup with two centrifugations comprising 400 × gfor 10 min + 400 ×gfor 10 min, in which the mean platelet concentration was 11.30 times higher than that of the control group. CONCLUSION: It was possible to obtain a high platelet concentration using viable simple techniques, by means of centrifugation of whole blood and use of commonly used materials. The most effective method for obtaining platelet concentrate was found in samples subjected to two centrifugations.

  15. TLR4 plays a crucial role in MSC-induced inhibition of NK cell function

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ying [No. 307 Hospital of the Chinese People' s Liberation Army, Beijing (China); Liu, Jin; Liu, Yang; Qin, Yaru [Beijing Institute of Radiation Medicine, Beijing (China); Luo, Qun [No. 307 Hospital of the Chinese People' s Liberation Army, Beijing (China); Wang, Quanli, E-mail: 13691110351@163.com [No. 307 Hospital of the Chinese People' s Liberation Army, Beijing (China); Duan, Haifeng, E-mail: duanhf0720@163.com [Beijing Institute of Radiation Medicine, Beijing (China)

    2015-08-21

    Mesenchymal stem cells (MSC) are a kind of stromal cell within the tumor microenvironment. In our research, MSC derived from acute myeloid leukemia patients' bone marrow (AML-MSC) and lung cancer tissues (LC-MSC) as well as normal bone marrow-derived MSC (BM-MSC) cultured in conditioned medium of HeLa cells were found to have higher expressions of Toll-like receptor (TLR4) mRNA compared with BM-MSC. The sorted TLR4-positive MSC (TLR4+ MSC) differed in cytokine (interleukin-6, interleukin-8, and monocyte chemoattractant protein-1) secretion from those of unsorted MSC. MSC was reported to inhibit natural killer (NK) cell proliferation and function. In this research, we confirmed that TLR4+ MSC aggravate this suppression. Furthermore, when TLR4 in the sorted cells were stimulated by LPS or following blocked by antibody, the suppression on NK cell proliferation and cytotoxicity were more intensive or recovered respectively. Compared to unsorted MSC, NKG2D receptor expression on NK cells were also inhibited by TLR4+ MSC. These findings suggest that activation of TLR4 pathway is important for TLR4+ MSC and MSC to obstruct anti-tumor immunity by inhibiting NK cell function, which may provide a potential stroma-targeted tumor therapy. - Highlights: • TLR4+ MSC inhibit NK cell proliferation in vivo and in vitro. • TLR4+ MSC inhibit NKG2D expression on NK cells and NK cell cytotoxicity. • The distinguished cytokine expression of TLR4+ MSC may contribute to the inhibition on NK cell function.

  16. Plasma centrifuge

    International Nuclear Information System (INIS)

    Ikehata, Takashi; Mase, Hiroshi

    1998-01-01

    The plasma centrifuge is one of statistical isotope separation processes which uses the centrifugal force of a J x B driven rotating plasma in a magnetic field to give rise to the mass-dependent radial transport of isotopic ions. The system has been developed as an alternative to the gas centrifuge because a much higher rotational velocity and separation factor have been achieved. In this review, the physical aspects of the plasma centrifuge followed by the recent experimental achievements are described, especially in comparison with the gas centrifuge. (author)

  17. Determination of a suitable set of loss models for centrifugal compressor performance prediction

    Directory of Open Access Journals (Sweden)

    Elkin I. GUTIÉRREZ VELÁSQUEZ

    2017-10-01

    Full Text Available Performance prediction in preliminary design stages of several turbomachinery components is a critical task in order to bring the design processes of these devices to a successful conclusion. In this paper, a review and analysis of the major loss mechanisms and loss models, used to determine the efficiency of a single stage centrifugal compressor, and a subsequent examination to determine an appropriate loss correlation set for estimating the isentropic efficiency in preliminary design stages of centrifugal compressors, were developed. Several semi-empirical correlations, commonly used to predict the efficiency of centrifugal compressors, were implemented in FORTRAN code and then were compared with experimental results in order to establish a loss correlation set to determine, with good approximation, the isentropic efficiency of single stage compressor. The aim of this study is to provide a suitable loss correlation set for determining the isentropic efficiency of a single stage centrifugal compressor, because, with a large amount of loss mechanisms and correlations available in the literature, it is difficult to ascertain how many and which correlations to employ for the correct prediction of the efficiency in the preliminary stage design of a centrifugal compressor. As a result of this study, a set of correlations composed by nine loss mechanisms for single stage centrifugal compressors, conformed by a rotor and a diffuser, are specified.

  18. Quantification of platelets obtained by different centrifugation protocols in SHR rats.

    Science.gov (United States)

    Yazigi Junior, João Alberto; Dos Santos, João Baptista Gomes; Xavier, Bruno Rodrigues; Fernandes, Marcela; Valente, Sandra Gomes; Leite, Vilnei Mattiolli

    2015-01-01

    To quantify the platelet concentration in the blood of SHR rats, by means of different centrifugation protocols, and to evaluate what the most effective method for obtaining platelets is. We used 40 male rats of the isogenic SHR lineage. The animals were divided into three groups: control, using whole blood without centrifugation; single centrifugation, using whole blood subjected to a single centrifugation at 200 × g and 400 × g; and double centrifugation, using whole blood subjected one centrifugation at different rotations, followed by collection of whole plasma subjected to another centrifugation at different rotations: 200 × g + 200 × g; 200 × g + 400 × g; 200 × g + 800 × g; 400 × g + 400 × g; 400 × g + 800 × g. Samples of 3 ml of blood were drawn from each animal by means of cardiac puncture. The blood was stored in Vacutainer collection tubes containing 3.2% sodium citrate. The blood from the control group animals was analyzed without being subjected to centrifugation. After the blood from the other groups of animals had been subjected to centrifugation, the whole plasma was collected and subjected to platelet counting in the lower third of the sample. We obtained greatest platelet enrichment in the subgroup with two centrifugations comprising 400 × g for 10 min + 400 × g for 10 min, in which the mean platelet concentration was 11.30 times higher than that of the control group. It was possible to obtain a high platelet concentration using viable simple techniques, by means of centrifugation of whole blood and use of commonly used materials. The most effective method for obtaining platelet concentrate was found in samples subjected to two centrifugations.

  19. Gamma irradiation and heat treatment for sterilization of Mushroom Spent Compost (MSC)

    International Nuclear Information System (INIS)

    Rosnani Abdul Rashid; Hassan Hamdani Mutaat; Foziah Ali; Zainab Harun; Hoe, P.C.K.; Mohd Meswan Maskom; Khairuddin Abdul Rahim

    2016-01-01

    Mushroom spent compost (MSC) refers to substrate residue from mushroom cultivation. MSC can be used as a material to improve soil properties for farming. MSC is also suitable as a carrier or substrate to hold beneficial microorganisms in bio fertilizer products. The carrier for bio fertilizer products must be sterilized completely before inoculating with bacteria inoculum. In this study, the effects of gamma irradiation and heat on sterilization of MSC were evaluated by microbial enumeration technique. The MSC was packed into polyethylene bags. The packed MSC were irradiated at different doses of 0 (control), 10, 20, 30, 40, 50 kGy, and heat sterilized at different autoclaving time of 0 (control), 15, 30, 45 and 60 minutes, separately. The irradiated and autoclaved samples were enumerated for viable colonies. The results showed that MSC was completely sterilized by gamma irradiation at the dose of 30 kGy whilst sterilization by heat required 30 minute autoclaving time. (author)

  20. Multi-staging for extraction of cesium from nitric acid by a single liquid-liquid countercurrent centrifugal extractor with Taylor vortices

    International Nuclear Information System (INIS)

    Nakase, Masahiko; Kinuhata, Hiroshi; Takeshita, Kenji

    2013-01-01

    Fission products that emit considerable decay heat and radioactivity, such as 137 Cs, have a large impact on waste management. Small and high-performance extractor is desirable for separating such nuclei. In this study, we implemented the continuous extraction of Cs from nitric acid in a single liquid-liquid countercurrent centrifugal extractor with Taylor Vortices by calix arene-bis(t-octylbenzo-crown-6)(BOBCalixC6) as an extractant with trioctylamine(TOA) as a suppressant and with 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB) as a phase modifier. Because of slow extraction kinetics of this process, extraction with multiple theoretical stages by just replacing conventional extractors into the single centrifugal extractor is difficult. Hence, we improved the dispersion of organic phase by an inner rotor made of lipophilic epoxy resin and elevating the solution temperature to lower the viscosity. Higher temperature was not appropriate from the aspect of chemical equilibrium in this process, but extraction with multiple theoretical stages was found to be possible. (author)

  1. CENTRIFUGAL SEPARATORS

    Science.gov (United States)

    Skarstrom, C.

    1959-03-10

    A centrifugal separator is described for separating gaseous mixtures where the temperature gradients both longitudinally and radially of the centrifuge may be controlled effectively to produce a maximum separation of the process gases flowing through. Tbe invention provides for the balancing of increases and decreases in temperature in various zones of the centrifuge chamber as the result of compression and expansions respectively, of process gases and may be employed effectively both to neutralize harmful temperature gradients and to utilize beneficial temperaturc gradients within the centrifuge.

  2. Centrifugal pumps

    CERN Document Server

    Anderson, HH

    1981-01-01

    Centrifugal Pumps describes the whole range of the centrifugal pump (mixed flow and axial flow pumps are dealt with more briefly), with emphasis on the development of the boiler feed pump. Organized into 46 chapters, this book discusses the general hydrodynamic principles, performance, dimensions, type number, flow, and efficiency of centrifugal pumps. This text also explains the pumps performance; entry conditions and cavitation; speed and dimensions for a given duty; and losses. Some chapters further describe centrifugal pump mechanical design, installation, monitoring, and maintenance. The

  3. Development of centrifugal contactor for FBR fuel reprocessing

    International Nuclear Information System (INIS)

    Washiya, Tadahiro; Takeuchi, Masayuki; Suganuma, Takashi; Aose, Shinichi; Ogino, Hideki

    2003-01-01

    In the Feasibility Study on Commercialized Fast Reactor Cycle Systems, the aqueous reprocessing technology is nominated as a candidate for future reprocessing system, which supposes to apply a centrifugal contactor in the extraction process. For the reprocessing plant, the centrifugal contactor has great advantages such as reducing solvent degradation, improving of equipment utilization rate, compact designing of equipment layout and critical safety domination. From these advantages, the centrifugal contactor is crucial equipment in the aqueous reprocessing process. Since 1985, JNC has been developing the centrifugal contactor. The single unit development has been accomplished and basic characteristics such as extraction performance, fluidic performance and remote maintenance performance have been determined. A durability test has been conducted for high longevity, with consideration given to the nitric acid mist and estimation of the equipment lifetime. System test equipment with centrifugal contactors of engineering scale was installed, and uranium test was conducted. Up to now, a standard flow sheet test in the extraction process and mal-operation test assuming the one stage shutdown condition have been performed. (author)

  4. Separations by centrifugal phenomena

    International Nuclear Information System (INIS)

    Hsu, H.W.

    1981-01-01

    The technical information presented herein emphasizes the uniqueness of the centrifugal separations methodology and pertinent theory for various kinds of centrifugation. The topics are arranged according to gas, liquid, and solid phases, in the order of increasing densities. Much space is devoted to liquid centrifugation because of the importance of this technique in chemical and biological laboratories. Many separational and characterizational examples are illustrated in detail. The material has been divided into 7 chapters entitled: 1) Introduction, 2) Basic Theory of Centrifugation, 3) Gas Centrifuges, 4) Preparative Liquid Centrifuges, 5) Analytical Liquid Centrifuges, 6) Liquid Centrifuges in Practice, and 7) Mechanical Separations by Centrifuges. Separate abstracts have been prepared for each chapter except the introduction

  5. Reflection of centrifugal pumps maintenance

    International Nuclear Information System (INIS)

    Mozos Fernandez, V.

    2010-01-01

    The aim of this work is to prove that is not necessary a deep and complex knowledge to manage the centrifugal pumps maintenance. According to the author, only deep but single technical knowledge about causes of breakdowns in the different and simple component parts of the pumps, are required. (Author)

  6. Centrifugal dewatering of acid casein curd: effect of casein manufacturing and centrifugation variables on curd compression in a laboratory centrifuge.

    Science.gov (United States)

    Munro, P A; Van Til, H J

    1988-10-20

    Data relevant to curd compression in a horizontal, solid bowl decanter centrifuge have been obtained by studying the dewatering of acid casein curd in a batch laboratory centrifuge. Analysis of curd compression under centrifugal force predicts a moisture content gradient in the dewatered curd from a maximum at the curd-liquid interface to a minimum at the centrifuge bowl wall. This moisture content gradient was also measured experimentally, and its practical implications are discussed. Increases in centrifugal force, centrifugation time, and centrifugation temperature all caused a marked de crease in dewatered curd moisture content, whereas in creases in precipitation pH and maximum washing temperature caused a smaller decrease in dewatered curd moisture content.

  7. Centrifugation

    International Nuclear Information System (INIS)

    Subbaramajer.

    1983-01-01

    The theoretical analysis of the processes taking place at centrifugal method of isotope separation taking into account the latest investigations, in particular, investigation of velocity field applying the theory of boundary layers in rotating gas is conducted. As a result of using power computers for the solution of hydrodynamics equations by numerical methods sufficiently exact solutions of main hydrodynamic equations, reflecting the real centrifuge construction are derived. The increase of calculation accuracy of the flow field reflected also on the accuracy of the diffusion equation solution. Three parameters of similarity (height of transfer unit, flow, mass transfer coefficient) and their connection with the flow field, elementary separation coefficient in a cetrifugal field and molecular diffusion coefficient is determined. Modified formulas for the separation coefficient and separation centrifuge power taking into account similarity parameter changes over the axis are derived. The possibility of determining the system of controlled parameters optimizing the separation centrifuge power is shown

  8. Interrogation of fibre Bragg gratings through a fibre optic rotary joint on a geotechnical centrifuge

    Science.gov (United States)

    Correia, Ricardo; James, Stephen W.; Marshall, Alec; Heron, Charles; Korposh, Sergiy

    2016-05-01

    The monitoring of an array of fibre Bragg gratings (FBGs) strain sensors was performed through a single channel, single mode fibre optic rotary joint (FORJ) mounted on a geotechnical centrifuge. The array of three FBGs was attached to an aluminum plate that was anchored at the ends and placed on the model platform of the centrifuge. Acceleration forces of up to 50g were applied and the reflection signal of the monitored FBGs recorded dynamically using a 2.5kHz FBG interrogator placed outside the centrifuge. The use of a FORJ allowed the monitoring of the FBGs without submitting the FBG interrogator to the high g-forces experienced in the centrifuge.

  9. Centrifuge modeling of monopiles

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte

    2010-01-01

    To gain a larger knowledge of the monopile foundation concept, centrifuge modeling is used by the geotechnical group at DTU. The centrifuge operated at DTU is a beam centrifuge and was built in 1976. In the recent years it has been upgraded with onboard data acquisition and control systems....... The capabilities of the centrifuge at DTU makes it possible to obtain a scale factor of 85 in experiments which equals a soil volume in prototype scale of a diameter of 40 meters and a depth of 40 meters. This paper describes centrifuge modeling theory, the centrifuge setup at DTU and as an example show results...... from centrifuge tests performed on large diameter piles installed in dry sand....

  10. Stability of cell-free DNA from maternal plasma isolated following a single centrifugation step.

    Science.gov (United States)

    Barrett, Angela N; Thadani, Henna A; Laureano-Asibal, Cecille; Ponnusamy, Sukumar; Choolani, Mahesh

    2014-12-01

    Cell-free fetal DNA can be used for prenatal testing with no procedure-related risk to the fetus. However, yield of fetal DNA is low compared with maternal cell-free DNA fragments, resulting in technical challenges for some downstream applications. To maximize the fetal fraction, careful blood processing procedures are essential. We demonstrate that fetal fraction can be preserved using a single centrifugation step followed by postage of plasma to the laboratory for further processing. Digital PCR was used to quantify copies of total, maternal, and fetal DNA present in single-spun plasma at time points over a two-week period, compared with immediately processed double-spun plasma, with storage at room temperature, 4°C, and -80°C representing different postage scenarios. There was no significant change in total, maternal, or fetal DNA copy numbers when single-spun plasma samples were stored for up to 1 week at room temperature and 2 weeks at -80°C compared with plasma processed within 4 h. Following storage at 4°C no change in composition of cell-free DNA was observed. Single-spun plasma can be transported at room temperature if the journey is expected to take one week or less; shipping on dry ice is preferable for longer journeys. © 2014 John Wiley & Sons, Ltd.

  11. Hungarian medical physics MSc education

    International Nuclear Information System (INIS)

    Legrady, D.; Czifrus, Z.; Zarand, P.; Aszodi, A.; Pesznyak, C.; Major, T.

    2012-01-01

    The medical physics specialisation aims at providing high level interdisciplinary theoretical and practical knowledge and readily applicable skills, which can put into action in both the clinical and the R and D field. The first competence based gradual medical physics course in the B.Sc./M.Sc. system in Hungary was launched two years ago at the Faculty of Natural Sciences of Budapest University of Technology and Economics managed by the Institute of Nuclear Techniques. The MSc programme was compiled on the base of EFOMP, IPEM, AAPM and IAEA recommendations. The course curriculum comprises fundamental physical subjects (atomic and molecular physics, nuclear physics and particle physics) as well as fundamental medical knowledge (anatomy, physiology and radiobiology) required for subjects of diagnostic and therapy. Students of this MSc branch may chose further subjects from a 'compulsory optional' set of subjects, which contains medical imaging, X-ray diagnostics, radiation therapy, magnetic resonance imaging, radiation protection, Monte Carlo calculation and its clinical applications, ultrasound diagnostics and nuclear medicine. (authors)

  12. CENTRIFUGE END CAP

    Science.gov (United States)

    Beams, J.W.; Snoddy, L.B.

    1960-08-01

    An end cap for ultra-gas centrifuges is designed to impart or remove angular momentum to or from the gas and to bring the entering gas to the temperature of the gas inside the centrifuge. The end cap is provided with slots or fins for adjusting the temperature and the angular momentum of the entering gas to the temperature and momentum of the gas in the centrifuge and is constructed to introduce both the inner and the peripheral stream into the centrifuge.

  13. Centrifugation. A theoretical study of oxygen enrichment by centrifugation

    Energy Technology Data Exchange (ETDEWEB)

    Kierkegaard, P.; Raetz, E.

    1998-12-01

    In the present paper we first investigate what happens if we fill a cylinder with air, close it and rotate it. The results show that no matter which peripheral speed is used, it is not possible by means of the radial separation effect alone, to enrich the oxygen concentration from the previous 21% to more then 23.3%, which is of no practical value. In case of a too low enrichment in one centrifuge, the wanted material from this centrifuge can be used as an input for a second centrifuge and so on, in this way forming a cascade of centrifuges. Oxygen will be enriched in each step, until the desired concentration is reached. Cascading was the technology in the very beginning by enrichment plants for uraniumhexaflouride, used for atomic weapons and nuclear power plants. In this study we try to avoid cascading by aiming for higher separation factors. Therefore, we next investigate the possibilities of using a countercurrent centrifuge where in principle the enriched gas is subjected to several centrifugation in the same centrifuge. The calculations show, that in this way it is possible to produce nearly a 100% pure oxygen (polluted with some heavier molecules like argon) in one machine. Our third step was to calculate the amount of oxygen produced per hour. Using a countercurrent centrifuge of the Zippe type, 100 cm high and 20 cm in diameter, it is or will be possible in the near future to produce 17 g enriched air per hour enriched to 50% oxygen. That corresponds to processing 1 m{sup 3} atmospherical air in the period of approximately 24 hours. This is not very impressive. Our fourth step was to estimate the amount of power used for producing this amount of oxygen. A rough, but complicated, estimate shows that the power consumption at the production level will be about the double of the consumption used today. The overall conclusion is, that centrifugation as a production method for oxygen (or nitrogen) will not be competitive with the currently used method in the

  14. Using PAFEC as a preprocessor for MSC/NASTRAN

    International Nuclear Information System (INIS)

    Gray, W.H.; Baudry, T.V.

    1983-01-01

    Programs for Automatic Finite Element Calculations (PAFEC) is a general-purpose, three-dimensional, linear and nonlinear finite element program. PAFEC's features include free-format input using engineering keywords, powerful mesh-generating facilities, sophisticated database management procedures, and extensive data validation checks. Presented here is a description of a software interface that permits PAFEC to be used as a preprocessor for MSC/NASTRAN. This user-friendly software, called PAFMSC, frees the stress analyst from the laborious and error-prone procedure of creating and debugging a rigid-format MSC/NASTRAN bulk data deck. By interactively creating and debugging a finite element model with PAFEC, thus taking full advantage of the free-format, engineering-keyword-oriented data structure of PAFEC, the stress analyst can drastically reduce the amount of time spent during model generation. The PAFMSC software will automatically convert a PAFEC data structure into an MSC/NASTRAN bulk data deck. The capabilities and limitations of the PAFMSC software are fully discussed in the following report

  15. Using PAFEC as a preprocessor for MSC/NASTRAN

    International Nuclear Information System (INIS)

    Gray, W.H.; Baudry, T.V.

    1983-01-01

    Programs for Automatic Finite Element Calculations (PAFEC) is a general-purpose, three-dimensional, linear and nonlinear finite element program. PAFEC's features include free-format input using engineering keywords, powerful mesh-generating facilities, sophisticated database management procedures, and extensive data validation checks. Presented here is a description of a software interface that permits PAFEC to be used as a preprocessor for MSC/NASTRAN. This user-friendly software, called PAFMSC, frees the stress analyst from the laborious and error-prone procedure of creating and debugging a rigid-format MSC/NASTRAN bulk data deck. By interactively creating and debugging a finite element model with PAFEC, thus taking full advantage of the free-format, engineering-keyword-oriented data structure of PAFEC, the stress analyst can drastically reduce the amount of time spent during model generation. The PAFMSC software will automatically convert a PAFEC data structure into an MSC/NASTRAN bulk data deck. The capabilities and limitations of the PAFMSC software are fully discussed

  16. Centrifuge enrichment program

    International Nuclear Information System (INIS)

    Astley, E.R.

    1976-01-01

    Exxon Nuclear has been active in privately funded research and development of centrifuge enrichment technology since 1972. In October of 1975, Exxon Nuclear submitted a proposal to design, construct, and operate a 3000-MT SWU/yr centrifuge enrichment plant, under the provisions of the proposed Nuclear Fuel Assurance Act of 1975. The U.S. Energy Research and Development Administration (ERDA) accepted the proposal as a basis for negotiation. It was proposed to build a 1000-MT SWU/yr demonstration increment to be operational in 1982; and after successful operation for about one year, expand the facilities into a 3000-MT SWU/yr plant. As part of the overall centrifuge enrichment plant, a dedicated centrifuge manufacturing plant would be constructed; sized to support the full 3000-MT SWU/yr plant. The selection of the centrifuge process by Exxon Nuclear was based on an extremely thorough evaluation of current and projected enrichment technology; results show that the technology is mature and the process will be cost effective. The substantial savings in energy (about 93%) from utilization of the centrifuge option rather than gaseous diffusion is a compelling argument. As part of this program, Exxon Nuclear has a large hardware R and D program, plus a prototype centrifuge manufacturing capability in Malta, New York. To provide a full-scale machine and limited cascade test capability, Exxon Nuclear is constructing a $4,000,000 Centrifuge Test Facility in Richland, Washington. This facility was to initiate operations in the Fall of 1976. Exxon Nuclear is convinced that the centrifuge enrichment process is the rational selection for emergence of a commercial enrichment industry

  17. Transcriptome Analyses of Mosaic (MSC Mitochondrial Mutants of Cucumber in a Highly Inbred Nuclear Background

    Directory of Open Access Journals (Sweden)

    Tomasz L. Mróz

    2018-03-01

    Full Text Available Cucumber (Cucumis sativus L. has a large, paternally transmitted mitochondrial genome. Cucumber plants regenerated from cell cultures occasionally show paternally transmitted mosaic (MSC phenotypes, characterized by slower growth, chlorotic patterns on the leaves and fruit, lower fertility, and rearrangements in their mitochondrial DNAs (mtDNAs. MSC lines 3, 12, and 16 originated from different cell cultures all established using the highly inbred, wild-type line B. These MSC lines possess different rearrangements and under-represented regions in their mtDNAs. We completed RNA-seq on normalized and non-normalized cDNA libraries from MSC3, MSC12, and MSC16 to study their nuclear gene-expression profiles relative to inbred B. Results from both libraries indicated that gene expression in MSC12 and MSC16 were more similar to each other than MSC3. Forty-one differentially expressed genes (DEGs were upregulated and one downregulated in the MSC lines relative to B. Gene functional classifications revealed that more than half of these DEGs are associated with stress-response pathways. Consistent with this observation, we detected elevated levels of hydrogen peroxide throughout leaf tissue in all MSC lines compared to wild-type line B. These results demonstrate that independently produced MSC lines with different mitochondrial polymorphisms show unique and shared nuclear responses. This study revealed genes associated with stress response that could become selection targets to develop cucumber cultivars with increased stress tolerance, and further support of cucumber as a model plant to study nuclear-mitochondrial interactions.

  18. Multiple-isotope separation in gas centrifuge

    International Nuclear Information System (INIS)

    Wood, Houston G.; Mason, T.C.; Soubbaramayer

    1996-01-01

    In previous works, the Onsager's pancake equation was used to provide solution to the internal counter-current flow field, which is necessary to calculate solutions to the isotope transport equation. The diffusion coefficient was assumed to be constant which is a good approximation for gases with large molecular weights, and small differences in the molecular weights of the various isotopes. A new optimization strategy was presented for determining the operating parameters of a gas centrifuge to be used for multiple-component isotope separation. Scoop drag, linear wall temperature gradient, the feed rate ant the cut have been chosen as operating parameters for the optimization. The investigation was restricted to a single centrifuge, and the problem of cascading for multiple-isotope separation was not addressed. The model describing the flow and separation phenomena in centrifuge includes a set of equations describing the fluid dynamics of the counter-current flow and the diffusion equations written for each isotope of the mixture. In this paper, an optimization algorithm is described and applied to an example for the re enrichment of spent reactor uranium

  19. USING OF MSC WITH DIFFERENT ONTOGENETIC MATURITY FOR CORRECTION OF CHRONIC FIBROSING LIVER DAMAGE

    Directory of Open Access Journals (Sweden)

    M. Y. Shagidulin

    2013-01-01

    Full Text Available Aim. To compare the effectiveness of MSC with different degree of ontogenetic maturity (MSC bone marrow – MSC BM and MSC umbilical cord – MSC UC on regenerative processes in injured liver. Methods. In 4 groups of experiments on Wistar rats (n = 80 with a model of fibrotic toxic liver damage (FLD it was studied the effect of MSCs with different degree of ontogenetic maturity on recovery processes at the regeneration of damaged liver: 1 gr. – Control, 2 gr. and 3 gr. introduction of MSC BM, included in Sphero®GEL-long in doses of 2.5 ×106 and 5.0 x 106 cells, respectively, and 4 gr. – introduction of MSC UC in the form of cell-spheroids (8–10 × 105 cells. The cells were injected into the damaged liver in 7 days after the end of FDL-modeling. The effect of cell therapy was studied during 180 days. The effectiveness of corrective therapy was evaluated by the results of functional and morphological investigations of livers (histological control of parenchymal and nonparenchy- mal liver tissue. Results. MSC BM in both doses and MSC UC contributed to a more rapid normalization of liver enzyme indices compared with the control (1 gr., but the differences in the rate of recovery of disturbed enzymatic liver functions between groups 2, 3 and 4 – were absent. In 90 days after the cell application it was determined a more pronounced recovery activity of cells in groups 3 and 4; in 180 days the more pronounced activation of recovery processes was observed in group 3; but in group 4 the sclerotic processes were more pro- nounced in this period. Conclusion. For the induction of recovery processes in damage liver it is advisable not to use the MSC UC, but to use MSC BM in the Sphero®GEL, because MSC BM exert not only local but also systemic immune-regulatory effect, increasing the pool of T-reg. cells, which are additional carriers of regenera- tion information in organism. 

  20. Hydraulic and separation characteristics of an industrial gas centrifuge calculated with neural networks

    Science.gov (United States)

    Butov, Vladimir; Timchenko, Sergey; Ushakov, Ivan; Golovkov, Nikita; Poberezhnikov, Andrey

    2018-03-01

    Single gas centrifuge (GC) is generally used for the separation of binary mixtures of isotopes. Processes taking place within the centrifuge are complex and non-linear. Their characteristics can change over time with long-term operation due to wear of the main structural elements of the GC construction. The paper is devoted to the determination of basic operation parameters of the centrifuge with the help of neural networks. We have developed a method for determining the parameters of the industrial GC operation by processing statistical data. In this work, we have constructed a neural network that is capable of determining the main hydraulic and separation characteristics of the gas centrifuge, depending on the geometric dimensions of the gas centrifuge, load value, and rotor speed.

  1. Solvent extraction studies in miniature centrifugal contactors

    International Nuclear Information System (INIS)

    Siczek, A.A.; Meisenhelder, J.H.; Bernstein, G.J.; Steindler, M.J.

    1980-01-01

    A miniature short-residence-time centrifugal solvent extraction contactor and an eight-stage laboratory minibank of centrifugal contactors were used for testing the possibility of utilizing kinetic effects for improving the separation of uranium from ruthenium and zirconium in the Purex process. Results of these tests showed that a small improvement found in ruthenium and zirconium decontamination in single-stage solvent extraction tests was lost in the multistage extraction tests- in fact, the extent of saturation of the solvent by uranium, rather than the stage residence time, controlled the extent of ruthenium and zirconium extraction. In applying the centrifugal contactor to the Purex process, the primary advantages would be less radiolytic damage to the solvent, high troughput, reduced solvent inventory, and rapid attainment of steady-state operating conditions. The multistage mini contactor was also tested to determine the suitability of short-residence-time contactors for use with the Civex and Thorex processes and was found to be compatible with the requirements of these processes. (orig.) [de

  2. 75 FR 70300 - USEC, Inc.; American Centrifuge Lead Cascade Facility; American Centrifuge Plant; Notice of...

    Science.gov (United States)

    2010-11-17

    ... Centrifuge Lead Cascade Facility; American Centrifuge Plant; Notice of Receipt of a License Transfer... SNM-2011, for the American Centrifuge Lead Cascade Facility and the American Centrifuge Plant... USEC Inc., (the Licensee), for its American Centrifuge Lead Cascade Facility (LCF) and American...

  3. Practical considerations in realizing a magnetic centrifugal mass filter

    Energy Technology Data Exchange (ETDEWEB)

    Gueroult, Renaud; Fisch, Nathaniel J. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    2012-12-15

    The magnetic centrifugal mass filter concept represents a variation on the plasma centrifuge, with applications that are particularly promising for high-throughput separation of ions with large mass differences. A number of considerations, however, constrain the parameter space in which this device operates best. The rotation speed, magnetic field intensity, and ion temperature are constrained by the ion confinement requirements. Collisions must also be large enough to eject ions, but small enough not to eject them too quickly. The existence of favorable regimes meeting these constraints is demonstrated by a single-particle orbit code. As an example of interest, it is shown that separation factors of about 2.3 are achievable in a single pass when separating Aluminum from Strontium ions.

  4. Cytokine treatment optimises the immunotherapeutic effects of umbilical cord-derived MSC for treatment of inflammatory liver disease.

    Science.gov (United States)

    de Witte, Samantha F H; Merino, Ana M; Franquesa, Marcella; Strini, Tanja; van Zoggel, Johanna A A; Korevaar, Sander S; Luk, Franka; Gargesha, Madhu; O'Flynn, Lisa; Roy, Debashish; Elliman, Steve J; Newsome, Philip N; Baan, Carla C; Hoogduijn, Martin J

    2017-06-08

    Mesenchymal stromal cells (MSC) possess immunomodulatory properties and low immunogenicity, both crucial properties for their development into an effective cellular immunotherapy. They have shown benefit in clinical trials targeting liver diseases; however the efficacy of MSC therapy will benefit from improvement of the immunomodulatory and immunogenic properties of MSC. MSC derived from human umbilical cords (ucMSC) were treated for 3 days in vitro with various inflammatory factors, interleukins, vitamins and serum deprivation. Their immunogenicity and immunomodulatory capacity were examined by gene-expression analysis, surface-marker expressions, IDO activity, PGE 2 secretion and inhibition of T cell proliferation and IFNγ production. Furthermore, their activation of NK cell cytotoxicity was investigated via CD107a expression on NK cells. The immunomodulatory capacity, biodistribution and survival of pre-treated ucMSC were investigated in a CCl 4 -induced liver disease mouse model. In addition, capacity of pre-treated MSC to ameliorate liver inflammation was examined in an ex vivo liver inflammation co-culture model. IFN-γ and a multiple cytokine cocktail (MC) consisting of IFN-γ, TGFβ and retinoic acid upregulated the expression of immunomodulatory factor PD-L1 and IDO activity. Subsequently, both treatments enhanced the capacity of ucMSC to inhibit CD4 and CD8 T cell proliferation and IFN-γ production. The susceptibility of ucMSC for NK cell lysis was decreased by IFN-β, TGFβ and MC treatment. In vivo, no immunomodulation was observed by the ucMSC. Four hours after intravenous infusion in mice with CCl 4 -induced inflammatory liver injury, the majority of ucMSC were trapped in the lungs. Rapid clearance of ucMSC(VitB 6 ), ucMSC(Starv + VitB 6 ) and ucMSC(MC) and altered bio-distribution of ucMSC(TGFβ) compared to untreated ucMSC was observed. In the ex vivo co-culture system with inflammatory liver slices ucMSC(MC) showed significantly enhanced

  5. CENTRIFUGE

    Science.gov (United States)

    Rushing, F.C.

    1960-09-01

    A vibration damping mechanism for damping vibration forces occurring during the operation of a centrifuge is described. The vibration damping mechanism comprises a plurality of nested spaced cylindrical elements surrounding the rotating shaft of the centrifuge. Some of the elements are held substantially stationary while the others are held with respect to a pair of hearings spaced along the rotating shaft. A fluid is retained about the cylindrical elements.

  6. RESEARCH CENTRIFUGE- ADVANCED TOOL SEPERATION

    OpenAIRE

    Mahajan Ashwini; Prof. B.V. Jain; Dr Surajj Sarode

    2015-01-01

    A centrifuge is a critical piece of equipment for the laboratory. Purpose of this study was to study research centrifuge in detail, its applications, uses in different branches and silent features. Their are two types of research centrifuge study here revolutionary research centrifuge and microprocessor research centrifuge. A centrifuge is a device that separates particles from a solution through use of a rotor. In biology, the particles are usually cells, sub cellular organelles, or large mo...

  7. Pipeline system for gas centrifuge

    International Nuclear Information System (INIS)

    Masumoto, Tsutomu; Umezawa, Sadao.

    1977-01-01

    Purpose: To enable effective operation for the gas centrifuge cascade system upon failures in the system not by interrupting the operation of all of the centrifuges in the system but by excluding only the failed centrifuges. Constitution: A plurality of gas centrifuges are connected by way of a pipeline and an abnormal detector for the automatic detection of abnormality such as destruction in a vacuum barrel and loss of vacuum is provided to each of the centrifuges. Bypass lines for short-circuitting adjacent centrifuges are provided in the pipelines connecting the centrifuges. Upon generation of abnormality in a centrifuge, a valve disposed in the corresponding bypass is automatically closed or opened by a signal from the abnormal detector to change the gas flow to thereby exclude the centrifuge in abnormality out of the system. This enables to effectively operate the system without interrupting the operation for the entire system. (Moriyama, K.)

  8. Injectable MMP-sensitive alginate hydrogels as hMSC delivery systems.

    Science.gov (United States)

    Fonseca, Keila B; Gomes, David B; Lee, Kangwon; Santos, Susana G; Sousa, Aureliana; Silva, Eduardo A; Mooney, David J; Granja, Pedro L; Barrias, Cristina C

    2014-01-13

    Hydrogels with the potential to provide minimally invasive cell delivery represent a powerful tool for tissue-regeneration therapies. In this context, entrapped cells should be able to escape the matrix becoming more available to actively participate in the healing process. Here, we analyzed the performance of proteolytically degradable alginate hydrogels as vehicles for human mesenchymal stem cells (hMSC) transplantation. Alginate was modified with the matrix metalloproteinase (MMP)-sensitive peptide Pro-Val-Gly-Leu-Iso-Gly (PVGLIG), which did not promote dendritic cell maturation in vitro, neither free nor conjugated to alginate chains, indicating low immunogenicity. hMSC were entrapped within MMP-sensitive and MMP-insensitive alginate hydrogels, both containing cell-adhesion RGD peptides. Softer (2 wt % alginate) and stiffer (4 wt % alginate) matrices were tested. When embedded in a Matrigel layer, hMSC-laden MMP-sensitive alginate hydrogels promoted more extensive outward cell migration and invasion into the tissue mimic. In vivo, after 4 weeks of subcutaneous implantation in a xenograft mouse model, hMSC-laden MMP-sensitive alginate hydrogels showed higher degradation and host tissue invasion than their MMP-insensitive equivalents. In both cases, softer matrices degraded faster than stiffer ones. The transplanted hMSC were able to produce their own collagenous extracellular matrix, and were located not only inside the hydrogels, but also outside, integrated in the host tissue. In summary, injectable MMP-sensitive alginate hydrogels can act as localized depots of cells and confer protection to transplanted cells while facilitating tissue regeneration.

  9. Plasma centrifuges

    International Nuclear Information System (INIS)

    Karchevskij, A.I.; Potanin, E.P.

    2000-01-01

    The review of the most important studies on the isotope separation processes in the rotating plasma is presented. The device is described and the characteristics of operation of the pulse plasma centrifuges with weakly and strongly ionized plasma as well as the stationary plasma centrifuges with the medium weak ionization and devices, applying the stationary vacuum arc with the high ionization rate and the stationary beam-plasma discharge with complete ionization, are presented. The possible mechanisms of the isotope separation in plasma centrifuges are considered. The specific energy consumption for isotope separation in these devices is discussed [ru

  10. Influences Factors of the Cadmium Removal by Magnetic Solid Chelator Powder(MSC in Soil

    Directory of Open Access Journals (Sweden)

    LIU Jun-long

    2017-12-01

    Full Text Available Pot experiments were conducted for the purpose of analyzing the influencing effects for the magnetic solid chelator powder(MSC, magnetic solid chelator powder on removal of cadmium pollution in the soil. The influencing factors included straws,air drying,activation structural material, stirring time and repetition times, etc. The results showed that the straw addition in the soil decreased the removal efficiency of Cd. The different air drying degree in the soil also had the effect of MSC. The air drying in the soil affected the results more by comparison with the straws. When stirring time was 40 min, the removal rate of Cd was 22.67% and achieved the best removal efficiency. With the increasing of stirring time, the effect of MSC on Cd removal increased first, then decreased. Drying MSC material lost the effect of Cd removal in the soil. After activation(soaking in water for 12 h, MSC material could remov Cd in the soil once again. MSC material had removal and remediation effects on soil Cd, the removal effects depended on soil properties, material properties and operation process and other factors. The research of MSC materials in soil remediation had important practical significance.

  11. Safety assessment of bone marrow derived MSC grown in platelet-rich plasma

    Directory of Open Access Journals (Sweden)

    Shoji Fukuda

    2015-06-01

    Full Text Available The injection of endothelial progenitor cells and mononuclear cells derived from bone marrow at the ischemic region of peripheral artery disease patients is reported to be effective for therapeutic angiogenesis; however, these cell therapies require large amounts of bone marrow to obtain sufficient numbers of cells. To solve this problem, we attempted to culture bone-marrow-derived mesenchymal stem cells (BM-MSC, which are supposed to secrete several cytokines that promote angiogenesis. We also focused on using platelet-rich plasma (PRP as a supplement for cell culture instead of fetal bovine serum. Human BM-MSC obtained from healthy volunteers expanded rapidly when cultured with 10% PRP prepared from their own blood. FACS analysis revealed that these cultured human MSC were homogeneous populations, and chromosomal analysis showed a normal karyotype. Moreover, the angiogenetic effect was apparent two weeks after human BM-MSC were injected into the ischemic muscle in SCID mice. Tumor formation was not detected three months after injection into SCID mice either subcutaneously or intramuscularly. To simulate clinical settings, canine BM-MSC were grown with canine PRP and injected into their ischemic muscles. We confirmed that donor cells existed in situ two and six weeks after operation without any side effects. These results suggest that cultured human BM-MSC can be a promising cell source for therapeutic angiogenesis.

  12. Marketing: MSc in logistics and transportation

    OpenAIRE

    Jenkins, Mark

    1983-01-01

    The objective of this course is to introduce the basic concepts of marketing to students undertaking an MSc in Transportation and Logistics. This module will take a strategic view of marketing in that it will develop ideas for achieving sustainable competitive advantage.

  13. Enriched surface acidity for surfactant-free suspensions of carboxylated carbon nanotubes purified by centrifugation

    Directory of Open Access Journals (Sweden)

    Elizabeth I. Braun

    2016-06-01

    Full Text Available It is well known that surfactant-suspended carbon nanotube (CNT samples can be purified by centrifugation to decrease agglomerates and increase individually-dispersed CNTs. However, centrifugation is not always part of protocols to prepare CNT samples used in biomedical applications. Herein, using carboxylated multi-walled CNTs (cMWCNTs suspended in water without a surfactant, we developed a Boehm titrimetric method for the analysis of centrifuged cMWCNT suspensions and used it to show that the surface acidity of oxidized carbon materials in aqueous cMWCNT suspensions was enriched by ∼40% by a single low-speed centrifugation step. This significant difference in surface acidity between un-centrifuged and centrifuged cMWCNT suspensions has not been previously appreciated and is important because the degree of surface acidity is known to affect the interactions of cMWCNTs with biological systems.

  14. Centrifugal separation of mixture gases

    International Nuclear Information System (INIS)

    Zhou, M.S.; Chen, W.N.; Yin, Y.T.

    2008-01-01

    An attempt for single centrifugal separation of mixtures with different molecular formula was presented in this paper. The mixtures of SF 6 and CCl 3 F, and SF 6 and CCl 4 were chosen as the processing gases, which were prepared in three mass ratios, 0.5, 0.8 and 0.2, respectively. The separating characteristics such as the overall separation factors and the variation of cuts were studied. (author)

  15. 76 FR 9613 - USEC Inc. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Order...

    Science.gov (United States)

    2011-02-18

    ... NUCLEAR REGULATORY COMMISSION [EA-11-013] USEC Inc. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Order Approving Direct Transfer of Licenses and Conforming Amendment I USEC... Centrifuge Lead Cascade Facility (Lead Cascade) and American Centrifuge Plant (ACP), respectively, which...

  16. 77 FR 9273 - USEC Inc. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Direct...

    Science.gov (United States)

    2012-02-16

    ... NUCLEAR REGULATORY COMMISSION [NRC-2010-0355] USEC Inc. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Direct Transfer of Licenses In the Matter of USEC INC. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Order EA-12- [[Page 9274

  17. Gas Centrifuges and Nuclear Proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Albright, David

    2004-09-15

    Gas centrifuges have been an ideal enrichment method for a wide variety of countries. Many countries have built gas centrifuges to make enriched uranium for peaceful nuclear purposes. Other countries have secretly sought centrifuges to make highly enriched uranium for nuclear weapons. In more recent times, several countries have secretly sought or built gas centrifuges in regions of tension. The main countries that have been of interest in the last two decades have been Pakistan, Iraq, Iran, and North Korea. Currently, most attention is focused on Iran, Pakistan, and North Korea. These states did not have the indigenous abilities to make gas centrifuges, focusing instead on illicit and questionable foreign procurement. The presentation covered the following main sections: Spread of centrifuges through illicit procurement; Role of export controls in stopping proliferation; Increasing the transparency of gas centrifuge programs in non-nuclear weapon states; and, Verified dismantlement of gas centrifuge programs. Gas centrifuges are important providers of low enriched uranium for civil nuclear power reactors. They also pose special nuclear proliferation risks. We all have special responsibilities to prevent the spread of gas centrifuges into regions of tension and to mitigate the consequences of their spread into the Middle East, South Asia, and North Asia.

  18. A new antibiotic with potent activity targets MscL.

    Science.gov (United States)

    Iscla, Irene; Wray, Robin; Blount, Paul; Larkins-Ford, Jonah; Conery, Annie L; Ausubel, Frederick M; Ramu, Soumya; Kavanagh, Angela; Huang, Johnny X; Blaskovich, Mark A; Cooper, Matthew A; Obregon-Henao, Andres; Orme, Ian; Tjandra, Edwin S; Stroeher, Uwe H; Brown, Melissa H; Macardle, Cindy; van Holst, Nick; Ling Tong, Chee; Slattery, Ashley D; Gibson, Christopher T; Raston, Colin L; Boulos, Ramiz A

    2015-07-01

    The growing problem of antibiotic-resistant bacteria is a major threat to human health. Paradoxically, new antibiotic discovery is declining, with most of the recently approved antibiotics corresponding to new uses for old antibiotics or structurally similar derivatives of known antibiotics. We used an in silico approach to design a new class of nontoxic antimicrobials for the bacteria-specific mechanosensitive ion channel of large conductance, MscL. One antimicrobial of this class, compound 10, is effective against methicillin-resistant Staphylococcus aureus with no cytotoxicity in human cell lines at the therapeutic concentrations. As predicted from in silico modeling, we show that the mechanism of action of compound 10 is at least partly dependent on interactions with MscL. Moreover we show that compound 10 cured a methicillin-resistant S. aureus infection in the model nematode Caenorhabditis elegans. Our work shows that compound 10, and other drugs that target MscL, are potentially important therapeutics against antibiotic-resistant bacterial infections.

  19. Root resistance to cavitation is accurately measured using a centrifuge technique.

    Science.gov (United States)

    Pratt, R B; MacKinnon, E D; Venturas, M D; Crous, C J; Jacobsen, A L

    2015-02-01

    Plants transport water under negative pressure and this makes their xylem vulnerable to cavitation. Among plant organs, root xylem is often highly vulnerable to cavitation due to water stress. The use of centrifuge methods to study organs, such as roots, that have long vessels are hypothesized to produce erroneous estimates of cavitation resistance due to the presence of open vessels through measured samples. The assumption that roots have long vessels may be premature since data for root vessel length are sparse; moreover, recent studies have not supported the existence of a long-vessel artifact for stems when a standard centrifuge technique was used. We examined resistance to cavitation estimated using a standard centrifuge technique and compared these values with native embolism measurements for roots of seven woody species grown in a common garden. For one species we also measured vulnerability using single-vessel air injection. We found excellent agreement between root native embolism and the levels of embolism measured using a centrifuge technique, and with air-seeding estimates from single-vessel injection. Estimates of cavitation resistance measured from centrifuge curves were biologically meaningful and were correlated with field minimum water potentials, vessel diameter (VD), maximum xylem-specific conductivity (Ksmax) and vessel length. Roots did not have unusually long vessels compared with stems; moreover, root vessel length was not correlated to VD or to the vessel length of stems. These results suggest that root cavitation resistance can be accurately and efficiently measured using a standard centrifuge method and that roots are highly vulnerable to cavitation. The role of root cavitation resistance in determining drought tolerance of woody species deserves further study, particularly in the context of climate change. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. SEAL FOR HIGH SPEED CENTRIFUGE

    Science.gov (United States)

    Skarstrom, C.W.

    1957-12-17

    A seal is described for a high speed centrifuge wherein the centrifugal force of rotation acts on the gasket to form a tight seal. The cylindrical rotating bowl of the centrifuge contains a closure member resting on a shoulder in the bowl wall having a lower surface containing bands of gasket material, parallel and adjacent to the cylinder wall. As the centrifuge speed increases, centrifugal force acts on the bands of gasket material forcing them in to a sealing contact against the cylinder wall. This arrangememt forms a simple and effective seal for high speed centrifuges, replacing more costly methods such as welding a closure in place.

  1. Cytokine treatment optimises the immunotherapeutic effects of umbilical cord-derived MSC for treatment of inflammatory liver disease

    OpenAIRE

    de Witte, Samantha F. H.; Merino, Ana M.; Franquesa, Marcella; Strini, Tanja; van Zoggel, Johanna A. A.; Korevaar, Sander S.; Luk, Franka; Gargesha, Madhu; O?Flynn, Lisa; Roy, Debashish; Elliman, Steve J.; Newsome, Philip N.; Baan, Carla C.; Hoogduijn, Martin J.

    2017-01-01

    Background Mesenchymal stromal cells (MSC) possess immunomodulatory properties and low immunogenicity, both crucial properties for their development into an effective cellular immunotherapy. They have shown benefit in clinical trials targeting liver diseases; however the efficacy of MSC therapy will benefit from improvement of the immunomodulatory and immunogenic properties of MSC. Methods MSC derived from human umbilical cords (ucMSC) were treated for 3?days in vitro with various inflammator...

  2. Centrifugal pump handbook

    CERN Document Server

    Pumps, Sulzer

    2010-01-01

    This long-awaited new edition is the complete reference for engineers and designers working on pump design and development or using centrifugal pumps in the field. This authoritative guide has been developed with access to the technical expertise of the leading centrifugal pump developer, Sulzer Pumps. In addition to providing the most comprehensive centrifugal pump theory and design reference with detailed material on cavitation, erosion, selection of materials, rotor vibration behavior and forces acting on pumps, the handbook also covers key pumping applications topics and operational

  3. Dihydrotestosterone induces pro-angiogenic factors and assists homing of MSC into the cardiac tissue.

    Science.gov (United States)

    Popa, Mirel-Adrian; Mihai, Maria-Cristina; Constantin, Alina; Şuică, Viorel; Ţucureanu, Cătălin; Costache, Raluca; Antohe, Felicia; Dubey, Raghvendra K; Simionescu, Maya

    2018-01-01

    The use of mesenchymal stem cells (MSC) as a therapeutic tool in cardiovascular diseases is promising. Since androgens exert some beneficial actions on the cardiovascular system, we tested our hypothesis that this hormone could promote MSC-mediated repair processes, also. Cultured MSCs isolated from Wharton's jelly were exposed to 30 nM dihydrotestosterone (DHT) for 1 or 4 days and the effects of the hormone on their growth/migration/adhesion and the underlying mechanisms were assessed. Results were obtained by real-time cell impedance measurements, and DNA quantification showed that DHT increased MSC proliferation by ~30%. As determined by xCELLigence system, DHT augmented (~2 folds) the migration of MSC toward cardiac tissue slices (at 12 h), and this effect was blocked by flutamide, an androgen receptor (AR) antagonist. Exposure of cells to DHT, upregulated the gene and protein expression of AR , EMMPRIN and MMP-9 and downregulated the expression of MMP-2 DHT significantly induced the release of nitric oxide by MSC (≥2-fold) and flutamide blocked this effect. When MSCs were co-cultured with cardiac slices, immunohistochemical analysis and qRT-PCR showed that the integration of DHT-stimulated MSC was significantly higher than that of in controls. In conclusion, our findings provide the first evidence that DHT promotes MSC growth, migration and integration into the cardiac slices. The modulating effects of DHT were associated with upregulation of ARs and of key molecules known to promote tissue remodeling and angiogenesis. Our findings suggest that priming of MSC with DHT may potentially increase their capability to regenerate cardiac tissue; in vivo studies are needed to confirm our in vitro findings. © 2018 Society for Endocrinology.

  4. Influence of the positive prewhirl on the performance of centrifugal pumps with different airfoils

    International Nuclear Information System (INIS)

    Zhou, C M; Wang, H M; Huang, X; Lin, H

    2012-01-01

    According to the basic theory of turbomachinery design and inlet guide vanes prewhirl regulation, two different airfoils inlet guide vanes of prewhirl regulation device were designed, the influence of the positive prewhirl to the performance of centrifugal pump were studied based on different airfoils. The results show that, for a single-suction centrifugal pump: Gottingen bowed blade-type inlet guide vane adjustment effect is better than straight blade-type inlet guide; appropriate design of positive prewhirl can elevate the efficiency of centrifugal pumps. Compared with no vane conditions, the efficiency of centrifugal pump with prewhirl vanes has been greatly improved and the power consumption has been reduced significantly, while has little influence on the head.

  5. Enrichment: centrifuge process

    International Nuclear Information System (INIS)

    Soubbaramayer.

    1989-01-01

    This short course is divided into three sections devoted respectively to the physics of the process, some practical problems raised by the design of a centrifuge and the present situation of centrifugation in the World. 31 figs., 18 refs

  6. Influences of centrifugation on cells and tissues in liposuction aspirates: optimized centrifugation for lipotransfer and cell isolation.

    Science.gov (United States)

    Kurita, Masakazu; Matsumoto, Daisuke; Shigeura, Tomokuni; Sato, Katsujiro; Gonda, Koichi; Harii, Kiyonori; Yoshimura, Kotaro

    2008-03-01

    Although injective autologous fat transplantation is one of the most attractive options for soft-tissue augmentation, problems such as unpredictability and fibrosis resulting from fat necrosis limit its universal acceptance. Centrifugation is one of most common methods for overcoming these difficulties. This study was performed to investigate quantitatively the effects of centrifugation on liposuction aspirates to optimize centrifugal conditions for fat transplantation and isolation of adipose-derived stem cells. Liposuction aspirates, obtained from eight healthy female donors, were either not centrifuged or centrifuged at 400, 700, 1200, 3000, or 4200 g for 3 minutes. The volumes of the oil, adipose, and fluid portions and numbers of blood cells and adipose-derived cells in each portion were examined. The processed adipose tissues (1 ml) were injected into athymic mice, and grafts were harvested and weighed at 4 weeks. Morphologic alterations were observed using light and scanning electron microscopy. Centrifugation concentrated adipose tissues and adipose-derived stem cells in the adipose portion and partly removed red blood cells from the adipose portion. Centrifugation at more than 3000 g significantly damaged adipose-derived stem cells. Centrifugation enhanced graft take per 1 ml centrifuged adipose but reduced calculated graft take per 1 ml adipose before centrifugation. Excessive centrifugation can destroy adipocytes and adipose-derived stem cells, but appropriate centrifugation concentrates them, resulting in enhanced graft take. The authors tentatively recommend 1200 g as an optimized centrifugal force for obtaining good short- and long-term results in adipose transplantation.

  7. Centrifuge apparatus

    Science.gov (United States)

    Sartory, Walter K.; Eveleigh, John W.

    1976-01-01

    A method and apparatus for operating a continuous flow blood separation centrifuge are provided. The hematocrit of the entrant whole blood is continuously maintained at an optimum constant value by the addition of plasma to the entrant blood. The hematocrit of the separated red cells is monitored to indicate the degree of separation taking place, thereby providing a basis for regulating the flow through the centrifuge.

  8. MSc degree in color technology for the automotive sector

    Science.gov (United States)

    Martinez-Verdu, F.; Perales, E.; Chorro, E.; Viqueira, V.; Gilabert, E.

    2014-07-01

    Nowadays, the measurement and management of color quality of the gonio-apparent materials is complex, but highly demanded in many industrial sectors, as automotive, cosmetics, plastics for consumer electronics, printing inks, architectural coatings, etc. It is necessary to control complex instrumentation and to do visual assessments of texture and color differences to get, for instance, a visual harmony in car bodies; and a profound knowledge of physics and chemistry of special-effect pigments for their optical formulation to obtain attractive visual effects in coatings, plastics, etc, combining among them and with solid pigments. From University of Alicante, for the academic year 2013-14, we are organizing the first MSc degree in Color Technology for the Automotive Sector, with a design of contents embracing CIE colorimetry and visual perception, included the AUDI2000 color difference formula, instrumentation and color management software, fundamentals of coatings and plastics in the automotive sector, and, optical formulation of pigments. The MSc syllabus, with 60 ECTS, is designed to be taught in two semesters: from September to February with on classroom theoretical and practical activities, and, from March to June at virtual level, with internships of training in some companies. Therefore, the MSc Thesis would be the performance report during the internship in companies or research institutions. Some multinational companies, both as car makers and coatings and plastics providers, from European and non-European countries have already shown their support and interest in welcoming students for specific training, even some job offers when the first MSc edition finishes.

  9. Suicide gene reveals the myocardial neovascularization role of mesenchymal stem cells overexpressing CXCR4 (MSC(CXCR4.

    Directory of Open Access Journals (Sweden)

    Jialiang Liang

    Full Text Available BACKGROUND: Our previous studies indicated that MSC(CXCR4 improved cardiac function after myocardial infarction (MI. This study was aimed to investigate the specific role of MSC(CXCR4 in neovascularization of infarcted myocardium using a suicide gene approach. METHODS: MSCs were transduced with either lentivirus-null vector/GFP (MSC(Null as control or vector encoding for overexpressing CXCR4/GFP. The MSC derived-endothelial cell (EC differentiation was assessed by a tube formation assay, Dil-ac-LDL uptake, EC marker expression, and VE-cadherin promoter activity assay. Gene expression was analyzed by quantitative RT-PCR or Western blot. The suicide gene approach was under the control of VE-cadherin promoter. In vivo studies: Cell patches containing MSC(Null or MSC(CXCR4 were transduced with suicide gene and implanted into the myocardium of MI rat. Rats received either ganciclovir (GCV or vehicle after cell implantation. After one month, the cardiac functional changes and neovascularization were assessed by echocardiography, histological analysis, and micro-CT imaging. RESULTS: The expression of VEGF-A and HIF-1α was significantly higher in MSC(CXCR4 as compared to MSC(Null under hypoxia. Additionally, MSC(CXCR4 enhanced new vessel formation and EC differentiation, as well as STAT3 phosphorylation under hypoxia. STAT3 participated in the transcription of VE-cadherin in MSC(CXCR4 under hypoxia, which was inhibited by WP1066 (a STAT3 inhibitor. In addition, GCV specifically induced death of ECs with suicide gene activation. In vivo studies: MSC(CXCR4 implantation promoted cardiac functional restoration, reduced infarct size, improved cardiac remodeling, and enhanced neovascularization in ischemic heart tissue. New vessels derived from MSC(CXCR4 were observed at the injured heart margins and communicated with native coronary arteries. However, the derived vessel networks were reduced by GCV, reversing improvement of cardiac function. CONCLUSION: The

  10. Separation parameters of gas centrifuges

    International Nuclear Information System (INIS)

    May, W.G.

    1977-01-01

    Early work on development of the gas centrifuge for separation of uranium isotopes has recently been reviewed. Several configurations were investigated. The preferred configuration eventually turned out to be a countercurrent centrifuge. In this form, an internal circulation is set up, and as a consequence, light isotope concentrates at one end of the centrifuge, heavy isotope at the other. In many ways the effect resembles the separation obtained in packed columns in the chemical and petroleum industries. It is the purpose of this paper to develop this analogy between countercurrent gas centrifuges and packed towers and to illustrate its usefulness in understanding the separation process in the centrifuge. 8 figures

  11. Optimasi Penambahan Colcemid pada Karyotyping Kultur Mecenchymal Stem Cells (MSC Mencit

    Directory of Open Access Journals (Sweden)

    Ratih Rinendyaputri

    2016-02-01

    Full Text Available AbstractControl of the genetic stability of stem cells prior to the conduct of therapy is essential to prevent effects such as stem cell transformation. Karyotyping is a conventional technique to conduct an analysis of the number and structure of chromosomes. The analysis can only be performed on metaphase stage that needs to be optimized to get the cell at that stage because the length of the cell cycle are different in the each cell types. This study aims to obtain an optimal time to get MSC at metaphase stage. The study was conducted at the stem cell laboratory of Center for Biomedical and Basic Technology of Health. The event begins with isolation using flushing technique at the femur and tibia of mice. Furthermore, the culture in vitro and induction colcemid 0,25μg/ml for 8,16 and 24 hours to get the MSC at metaphase stage. KCl solution with a concentration of 0.075 M and 0,045 M used as a solvent hipotonis. Results showed that 16 hours of induction colcemid 0,25μg/ml in 0.075 M KCl solution usage percentage of MSC who are at metaphase stage and do the highest analysis (p<0.05. In this study 16 hours induction colcemid 0,25μg/ml is the optimal time to obtain metaphase stage of the MSC from bone marrow of mice.Keywords: mecenchymal stem cell, karyotyping, colcemidAbstrakKontrol terhadap stabilitas genetik pada sel punca sebelum pelaksanan terapi merupakan hal yang penting untuk mencegah efek seperti transformasi sel punca yang dapat terjadi. Secara konvensional dapat dilakukan karyotyping untuk melakukan analisis terhadap jumlah dan struktur kromosom. Analisis hanya dapat dilakukan pada tahap metafase sehingga perlu dilakukan optimasi untuk mendapatkan sel pada tahap tersebut mengingat panjang siklus sel setiap jenis sel berbeda. Penelitian ini bertujuan untuk memperoleh waktu yang optimal untuk mendapatkan MSC pada tahap metafase. Penelitian dilakukan di Laboratorium stem cell Pusat Biomedis dan Teknologi Dasar Kesehatan Badan Litbangkes

  12. Instant stem cell therapy: Characterization and concentration of human mesenchymal stem cells in vitro

    Directory of Open Access Journals (Sweden)

    P Kasten

    2008-10-01

    Full Text Available In regenerative medicine, there is an approach to avoid expansion of the mesenchymal stem cell (MSC before implantation. The aim of this study was to compare methods for instant MSC therapy by use of a portable, automatic and closed system centrifuge that allows for the concentration of MSCs. The main outcome measures were the amount of MSCs per millilitre of bone marrow (BM, clusters of differentiation (CD, proliferation and differentiation capacities of the MSC. A volume reduction protocol was compared to the traditional laboratory methods of isolation using a Ficoll gradient and native BM. Fifty millilitres of BM were obtained from haematologically healthy male Caucasians (n=10, age 8 to 49 years. The number of colony forming units-fibroblast (CFU-F/ml BM was highest in the centrifuge volume reduction protocol, followed by the native BM (not significant, the centrifuge Ficoll (p=0.042 and the manual Ficoll procedure (p=0.001. The MSC of all groups could differentiate into the mesenchymal lineages without significant differences between the groups. The CD pattern was identical for all groups: CD13+; CD 44+; CD73 +; CD90+; CD105+; HLA-A,B,C+; CD14-; CD34-; CD45-; CD271-; HLA-DR-. In a further clinical pilot study (n=5 with 297 ml BM (SD 18.6, the volume reduction protocol concentrated the MSC by a factor of 14: there were 1.08 x 102 MSC/ml BM (standard deviation (SD 1.02 x 102 before concentration, 14.8 x 102 MSC/ ml BM (SD 12.4 x 102 after concentration, and on average 296 x 102 MSC (SD 248.9 x 102, range 86.4-691.5 x 102 were available for MSC therapy. The volume reduction protocol of the closed centrifuge allows for the highest concentration of the MSC, and therefore, is a promising candidate for instant stem cell therapy.

  13. Microwave assisted centrifuge and related methods

    Science.gov (United States)

    Meikrantz, David H [Idaho Falls, ID

    2010-08-17

    Centrifuge samples may be exposed to microwave energy to heat the samples during centrifugation and to promote separation of the different components or constituents of the samples using a centrifuge device configured for generating microwave energy and directing the microwave energy at a sample located in the centrifuge.

  14. 76 FR 50767 - In the Matter of USEC Inc., American Centrifuge Lead Cascade Facility, and American Centrifuge...

    Science.gov (United States)

    2011-08-16

    ...; License Nos. SNM-7003, SNM-2011] In the Matter of USEC Inc., American Centrifuge Lead Cascade Facility, and American Centrifuge Plant; Order Extending the Date by Which the Direct Transfer of Licenses Is To... American Centrifuge Lead Cascade Facility (Lead Cascade) and American Centrifuge Plant (ACP), respectively...

  15. Optimization and translation of MSC-based hyaluronic acid hydrogels for cartilage repair

    Science.gov (United States)

    Erickson, Isaac E.

    2011-12-01

    Traumatic injury and disease disrupt the ability of cartilage to carry joint stresses and, without an innate regenerative response, often lead to degenerative changes towards the premature development of osteoarthritis. Surgical interventions have yet to restore long-term mechanical function. Towards this end, tissue engineering has been explored for the de novo formation of engineered cartilage as a biologic approach to cartilage repair. Research utilizing autologous chondrocytes has been promising, but clinical limitations in their yield have motivated research into the potential of mesenchymal stem cells (MSCs) as an alternative cell source. MSCs are multipotent cells that can differentiate towards a chondrocyte phenotype in a number of biomaterials, but no combination has successfully recapitulated the native mechanical function of healthy articular cartilage. The broad objective of this thesis was to establish an MSC-based tissue engineering approach worthy of clinical translation. Hydrogels are a common class of biomaterial used for cartilage tissue engineering and our initial work demonstrated the potential of a photo-polymerizable hyaluronic acid (HA) hydrogel to promote MSC chondrogenesis and improved construct maturation by optimizing macromer and MSC seeding density. The beneficial effects of dynamic compressive loading, high MSC density, and continuous mixing (orbital shaker) resulted in equilibrium modulus values over 1 MPa, well in range of native tissue. While compressive properties are crucial, clinical translation also demands that constructs stably integrate within a defect. We utilized a push-out testing modality to assess the in vitro integration of HA constructs within artificial cartilage defects. We established the necessity for in vitro pre-maturation of constructs before repair to achieve greater integration strength and compressive properties in situ. Combining high MSC density and gentle mixing resulted in integration strength over 500 k

  16. Fit for purpose? Evaluation of an MSc. in Medical Physics.

    LENUS (Irish Health Repository)

    van der Putten, W J

    2014-05-01

    The National University of Ireland in Galway established a Master in Science (MSc.) program in medical physics in 2002. The course was designed to be 90 ECTS(1) credits and of one calendar year duration. From the outset the MSc. was designed to be part of an overall medical physics training program. MSc. programs are now widely used as part of the training and education of medical physicists. There is however paucity of data on the effectiveness of such courses and the purpose of the study reported here is to provide information on one particular MSc. course in medical physics. This is relevant to medical physicists who are involved in the development and running of medical physics training programs. The study used as methodology the Kirkpatrick levels of professional training. It was conducted through an online survey, both from students who graduated from the course and from students who were in the process of completing the course. The survey proved to be an effective way to determine attributes of modules such as learning outcomes, knowledge imparted, quality of teaching materials and others. The survey proved to be remarkably able to demonstrate interventions in the individual course modules. Although the course was shown to be effective in the imparting of the knowledge required to become a qualified medical physicist several areas for improvement were identified. These are mainly in the areas of increased practical experience and in course delivery.

  17. Umbilical cord mesenchymal stem cell (UC-MSC) transplantations for cerebral palsy

    Science.gov (United States)

    Dong, Huajiang; Li, Gang; Shang, Chongzhi; Yin, Huijuan; Luo, Yuechen; Meng, Huipeng; Li, Xiaohong; Wang, Yali; Lin, Ling; Zhao, Mingliang

    2018-01-01

    This study reports a case of a 4-year-old boy patient with abnormalities of muscle tone, movement and motor skills, as well as unstable gait leading to frequent falls. The results of the electroencephalogram (EEG) indicate moderately abnormal EEG, accompanied by irregular seizures. Based on these clinical characteristics, the patient was diagnosed with cerebral palsy (CP) in our hospital. In this study, the patient was treated with umbilical cord mesenchymal stem cell (UC-MSC) transplantation therapy. This patient received UC-MSC transplantation 3 times (5.3*107) in total. After three successive cell transplantations, the patient recovered well and showed obvious improvements in EEG and limb strength, motor function, and language expression. However, the improvement in intelligence quotient (IQ) was less obvious. These results indicate that UC-MSC transplantation is a promising treatment for cerebral palsy. PMID:29636880

  18. Combined MSC and GLP-1 Therapy Modulates Collagen Remodeling and Apoptosis following Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Elizabeth J. Wright

    2016-01-01

    Full Text Available Background. Mesenchymal stem cells (MSCs and glucagon-like peptide-1 (GLP-1 are being tested as treatment strategies for myocardial infarction (MI; however, their mechanisms in the heart are not fully understood. Methods. We examined the effects of MSCs, either native, or engineered to secrete a GLP-1 fusion protein (MSCs ± GLP-1, on human cardiomyocyte apoptosis in vitro. The effect on cardiac remodeling when encapsulated in alginate beads (CellBeads-MSC and CellBeads-MSC + GLP-1 was also evaluated in a pig MI model, whereby pigs were treated with Empty Beads, CellBeads-MSC, or CellBeads-MSC + GLP-1 and sacrificed at one or four weeks following MI. Results. MSC + GLP-1 conditioned media demonstrated antiapoptotic effects on ischaemic human cardiomyocytes in vitro. In vivo, qRT-PCR revealed large changes in the expression of several genes involved in extracellular matrix remodeling, which were altered following MSC ± GLP treatment. After four weeks, infarcted areas were imaged using atomic force microscopy, demonstrating significant alterations between groups in the structure of collagen fibrils and resulting scar. Conclusions. These data demonstrate that MSCs ± GLP-1 exhibit modulatory effects on healing post-MI, affecting both apoptosis and collagen scar formation. These data support the premise that both MSCs and GLP-1 could be beneficial in MI treatment.

  19. Centrifugal precipitation chromatography

    Science.gov (United States)

    Ito, Yoichiro; Lin, Qi

    2009-01-01

    Centrifugal precipitation chromatography separates analytes according their solubility in ammonium sulfate (AS) solution and other precipitants. The separation column is made from a pair of long spiral channels partitioned with a semipermeable membrane. In a typical separation, concentrated ammonium sulfate is eluted through one channel while water is eluted through the other channel in the opposite direction. The countercurrent process forms an exponential AS concentration gradient through the water channel. Consequently, protein samples injected into the water channel is subjected to a steadily increasing AS concentration and at the critical AS concentration they are precipitated and deposited in the channel bed by the centrifugal force. Then the chromatographic separation is started by gradually reducing the AS concentration in the AS channel which lowers the AS gradient concentration in the water channel. This results in dissolution of deposited proteins which are again precipitated at an advanced critical point as they move through the channel. Consequently, proteins repeat precipitation and dissolution through a long channel and finally eluted out from the column in the order of their solubility in the AS solution. The present method has been successfully applied to a number of analytes including human serum proteins, recombinant ketosteroid isomerase, carotenoid cleavage enzymes, plasmid DNA, polysaccharide, polymerized pigments, PEG-protein conjugates, etc. The method is capable to single out the target species of proteins by affinity ligand or immunoaffinity separation. PMID:19541553

  20. Centrifuge design and development

    International Nuclear Information System (INIS)

    Edwards, T.T.; Holmes, M.D.

    1987-01-01

    BNFL has been enriching uranium on an industrial scale using the centrifuge process for over a decade. Together with its Urenco partners, a joint development programme has been and is being vigorously pursued to reduce specific costs, increase output and maintain competitiveness throughout the 1990s. The paper summarises the development of the centrifuge from its earliest concepts through to the centrifuges of today which are jointly designed by the Urenco partners. The potential for further development is also examined. (author)

  1. Fluid-structure coupling effects on periodically transient flow of a single-blade sewage centrifugal pump

    International Nuclear Information System (INIS)

    Pei, Ji; Yuan, Shouqi; Yuan, Jianping

    2013-01-01

    A partitioned fluid-structure interaction (FSI) solving strategy that depends on problem characteristics is applied to quantitatively obtain the coupling effects of a fluid-structure system in a single-blade centrifugal pump on the unsteady flow. A two-way coupling method is employed to realize strong FSI effects in the calculation procedure. The successful impeller oscillation measurement using two proximity sensors validated the FSI simulation accuracy in a complicated and practical fluid-structure system having a rotating component. The results show that the hydrodynamic force deviation can be observed in the results for the coupled versus uncoupled cases. Additionally, the coupled unsteady pressure is larger than the uncoupled value for every monitoring point at every impeller rotation position. Comparison results for different monitoring points under an overload condition and partial-load condition display the same regularities. To some extent, this interaction mechanism would affect the accuracy and reliability of the unsteady flow and rotor deflection analysis.

  2. Phenotypic, Functional, and Safety Control at Preimplantation Phase of MSC-Based Therapy

    Science.gov (United States)

    Lech, Wioletta; Figiel-Dabrowska, Anna; Drela, Katarzyna; Obtulowicz, Patrycja; Noszczyk, Bartlomiej Henryk; Buzanska, Leonora

    2016-01-01

    Mesenchymal stem cells (MSC) exhibit enormous heterogeneity which can modify their regenerative properties and therefore influence therapeutic effectiveness as well as safety of these cells transplantation. In addition the high phenotypic plasticity of MSC population makes it enormously sensitive to any changes in environmental properties including fluctuation in oxygen concentration. We have shown here that lowering oxygen level far below air atmosphere has a beneficial impact on various parameters characteristic for umbilical cord Wharton Jelly- (WJ-) MSC and adipose tissue- (AD-) derived MSC cultures. This includes their cellular composition, rate of proliferation, and maintenance of stemness properties together with commitment to cell differentiation toward mesodermal and neural lineages. In addition, the culture genomic stability increased significantly during long-term cell passaging and eventually protected cells against spontaneous transformation. Also by comparing of two routinely used methods of MSCs isolation (mechanical versus enzymatic) we have found substantial divergence arising between cell culture properties increasing along the time of cultivation in vitro. Thus, in this paper we highlight the urgent necessity to develop the more sensitive and selective methods for prediction and control cells fate and functioning during the time of growth in vitro. PMID:27651796

  3. Phenotypic, Functional, and Safety Control at Preimplantation Phase of MSC-Based Therapy.

    Science.gov (United States)

    Lech, Wioletta; Figiel-Dabrowska, Anna; Sarnowska, Anna; Drela, Katarzyna; Obtulowicz, Patrycja; Noszczyk, Bartlomiej Henryk; Buzanska, Leonora; Domanska-Janik, Krystyna

    2016-01-01

    Mesenchymal stem cells (MSC) exhibit enormous heterogeneity which can modify their regenerative properties and therefore influence therapeutic effectiveness as well as safety of these cells transplantation. In addition the high phenotypic plasticity of MSC population makes it enormously sensitive to any changes in environmental properties including fluctuation in oxygen concentration. We have shown here that lowering oxygen level far below air atmosphere has a beneficial impact on various parameters characteristic for umbilical cord Wharton Jelly- (WJ-) MSC and adipose tissue- (AD-) derived MSC cultures. This includes their cellular composition, rate of proliferation, and maintenance of stemness properties together with commitment to cell differentiation toward mesodermal and neural lineages. In addition, the culture genomic stability increased significantly during long-term cell passaging and eventually protected cells against spontaneous transformation. Also by comparing of two routinely used methods of MSCs isolation (mechanical versus enzymatic) we have found substantial divergence arising between cell culture properties increasing along the time of cultivation in vitro. Thus, in this paper we highlight the urgent necessity to develop the more sensitive and selective methods for prediction and control cells fate and functioning during the time of growth in vitro.

  4. Finding and tracing human MSC in 3D microenvironments with the photoconvertible protein Dendra2

    Science.gov (United States)

    Caires, Hugo R.; Gomez-Lazaro, Maria; Oliveira, Carla M.; Gomes, David; Mateus, Denisa D.; Oliveira, Carla; Barrias, Cristina C.; Barbosa, Mário A.; Almeida, Catarina R.

    2015-05-01

    Mesenchymal Stem/Stromal Cells (MSC) are a promising cell type for cell-based therapies - from tissue regeneration to treatment of autoimmune diseases - due to their capacity to migrate to damaged tissues, to differentiate in different lineages and to their immunomodulatory and paracrine properties. Here, a simple and reliable imaging technique was developed to study MSC dynamical behavior in natural and bioengineered 3D matrices. Human MSC were transfected to express a fluorescent photoswitchable protein, Dendra2, which was used to highlight and follow the same group of cells for more than seven days, even if removed from the microscope to the incubator. This strategy provided reliable tracking in 3D microenvironments with different properties, including the hydrogels Matrigel and alginate as well as chitosan porous scaffolds. Comparison of cells mobility within matrices with tuned physicochemical properties revealed that MSC embedded in Matrigel migrated 64% more with 5.2 mg protein/mL than with 9.6 mg/mL and that MSC embedded in RGD-alginate migrated 51% faster with 1% polymer concentration than in 2% RGD-alginate. This platform thus provides a straightforward approach to characterize MSC dynamics in 3D and has applications in the field of stem cell biology and for the development of biomaterials for tissue regeneration.

  5. Vacuum chamber-free centrifuge with magnetic bearings.

    Science.gov (United States)

    Park, Cheol Hoon; Kim, Soohyun; Kim, Kyung-Soo

    2013-09-01

    Centrifuges are devices that separate particles of different densities and sizes through the application of a centrifugal force. If a centrifuge could be operated under atmospheric conditions, all vacuum-related components such as the vacuum chamber, vacuum pump, diffusion pump, and sealing could be removed from a conventional centrifuge system. The design and manufacturing procedure for centrifuges could then be greatly simplified to facilitate the production of lightweight centrifuge systems of smaller volume. Furthermore, the maintenance costs incurred owing to wear and tear due to conventional ball bearings would be eliminated. In this study, we describe a novel vacuum chamber-free centrifuge supported by magnetic bearings. We demonstrate the feasibility of the vacuum chamber-free centrifuge by presenting experimental results that verify its high-speed support capability and motoring power capacity.

  6. One-step derivation of mesenchymal stem cell (MSC-like cells from human pluripotent stem cells on a fibrillar collagen coating.

    Directory of Open Access Journals (Sweden)

    Yongxing Liu

    Full Text Available Controlled differentiation of human embryonic stem cells (hESCs and induced pluripotent stem cells (iPSCs into cells that resemble adult mesenchymal stem cells (MSCs is an attractive approach to obtain a readily available source of progenitor cells for tissue engineering. The present study reports a new method to rapidly derive MSC-like cells from hESCs and hiPSCs, in one step, based on culturing the cells on thin, fibrillar, type I collagen coatings that mimic the structure of physiological collagen. Human H9 ESCs and HDFa-YK26 iPSCs were singly dissociated in the presence of ROCK inhibitor Y-27632, plated onto fibrillar collagen coated plates and cultured in alpha minimum essential medium (alpha-MEM supplemented with 10% fetal bovine serum, 50 uM magnesium L-ascorbic acid phosphate and 100 nM dexamethasone. While fewer cells attached on the collagen surface initially than standard tissue culture plastic, after culturing for 10 days, resilient colonies of homogenous spindle-shaped cells were obtained. Flow cytometric analysis showed that a high percentage of the derived cells expressed typical MSC surface markers including CD73, CD90, CD105, CD146 and CD166 and were negative as expected for hematopoietic markers CD34 and CD45. The MSC-like cells derived from pluripotent cells were successfully differentiated in vitro into three different lineages: osteogenic, chondrogenic, and adipogenic. Both H9 hES and YK26 iPS cells displayed similar morphological changes during the derivation process and yielded MSC-like cells with similar properties. In conclusion, this study demonstrates that bioimimetic, fibrillar, type I collagen coatings applied to cell culture plates can be used to guide a rapid, efficient derivation of MSC-like cells from both human ES and iPS cells.

  7. Synthesis of Mesoporous Single Crystal Co(OH)2 Nanoplate and Its Topotactic Conversion to Dual-Pore Mesoporous Single Crystal Co3O4.

    Science.gov (United States)

    Jia, Bao-Rui; Qin, Ming-Li; Li, Shu-Mei; Zhang, Zi-Li; Lu, Hui-Feng; Chen, Peng-Qi; Wu, Hao-Yang; Lu, Xin; Zhang, Lin; Qu, Xuan-Hui

    2016-06-22

    A new class of mesoporous single crystalline (MSC) material, Co(OH)2 nanoplates, is synthesized by a soft template method, and it is topotactically converted to dual-pore MSC Co3O4. Most mesoporous materials derived from the soft template method are reported to be amorphous or polycrystallined; however, in our synthesis, Co(OH)2 seeds grow to form single crystals, with amphiphilic block copolymer F127 colloids as the pore producer. The single-crystalline nature of material can be kept during the conversion from Co(OH)2 to Co3O4, and special dual-pore MSC Co3O4 nanoplates can be obtained. As the anode of lithium-ion batteries, such dual-pore MSC Co3O4 nanoplates possess exceedingly high capacity as well as long cyclic performance (730 mAh g(-1) at 1 A g(-1) after the 350th cycle). The superior performance is because of the unique hierarchical mesoporous structure, which could significantly improve Li(+) diffusion kinetics, and the exposed highly active (111) crystal planes are in favor of the conversion reaction in the charge/discharge cycles.

  8. Flow control arrangements for centrifuges

    International Nuclear Information System (INIS)

    Alderton, G.W.; Davidge, P.C.

    1983-01-01

    In a centrifuge plant for the separation of uranium isotopes, when a centrifuge machine breaks down, light gas is produced. This gas can cause adjacent machines to break down, so propagating the fault. The present invention provides flow control arrangements in gas pipes to the centrifuge, whereby sudden egress of gas from a failed machine is inhibited. (author)

  9. Evaluation of enrichment by centrifugal separation: the future of the centrifugal-separation method

    International Nuclear Information System (INIS)

    Kanagawa, A.

    A gas centrifuge plant for uranium enrichment is considered from the point of view of economic competition with other methods. Characteristics of the method are presented including: energy efficiency, the cascade, the separation coefficient, the equilibrium separation process, and capability as centrifugal pump. The structure of an individual gas centrifuge separator is described including the rotating cylinder, mechanisms for gas injection and extraction, mechanisms for counter-streaming of gas, the axle holder mechanism, the gas sealing mechanism, and the driving mechanism. (U.S.)

  10. Numerical simulation of bellows effect on flow and separation of uranium isotopes in a supercritical gas centrifuge

    International Nuclear Information System (INIS)

    Borisevich, V.D.; Morozov, O.E.; Godisov, O.N.

    2000-01-01

    Numerical solving of the Navier-Stokes and convection-diffusion equations by the finite difference technique has been applied to study the influence of bellows on the flow and separation of uranium isotopes in a single supercritical gas centrifuge. Dependence of the separative power of a gas centrifuge on geometric parameters and position of a bellows on a rotor wall as well as the effect of scoop drag and feed flow on isotope separation in a gas centrifuge with a bellows have been obtained in computing experiments. It was demonstrated that increase of the separative power with increase of the gas centrifuge length is less considerable than predicted by the Dirac's law

  11. Determining total sulfur content in coal by MSC radiometric sulfur meter

    Energy Technology Data Exchange (ETDEWEB)

    Czerw, B; Sikora, T; Golebiowski, W

    1976-01-01

    The MSC radiometric sulfur meter is used to determine total sulfur content in brown and black coals. Sulfur content is determined by measuring intensity of radiation beam which has travelled through a coal sample with the optimum constant surface mass. Construction of the MSC, consisting of a measuring head and the electronic measuring system, is shown in a scheme. AM-241 (with activity of 50 mCi) is the source of radiation. Energy of 25.3 keV (tin disc) is selected as the optimum. The SSU-70 probe with NaJ/Tl crystal is the radiation detector. The black coal sample weighs 10 g and the brown coal sample weighs 18 g. Duration of sulfur determination is 10 min. Error of sulfur determination ranges from plus or minus 0.2% to 0.3%. The results of operational tests of MSC radiometric sulfur meters in black and brown coal mines are discussed. Accuracy of measurement is shown in 5 tables. (8 refs.)

  12. Infusion of Trx-1-overexpressing hucMSC prolongs the survival of acutely irradiated NOD/SCID mice by decreasing excessive inflammatory injury.

    Directory of Open Access Journals (Sweden)

    JiangWei Hu

    Full Text Available A protective reagent for ARI should have the ability to repair injured tissue caused by radiation and prevent continuous damage from secondary risk factors. Trx-1 was explored as a candidate therapy for ARI, as it scavenges reactive oxygen species, regulates cell growth and differentiation, participates in immune reactions, and inhibits apoptosis by acting inside and/or outside cells. Trx-1 can also decrease excessive inflammation in ARI by regulating the creation of inflamed media, by inhibiting the activation of complement, and by reducing the chemotaxis, adhesion, and migration of inflammatory cells. As effectively and stably expressing exogenous genes in the long term and regulating immune inflammation and tissue repair, MSC are a good choice for Trx-1 gene therapy. In this study, Trx-1-overexpressing hucMSC-Trx-1 were obtained by adenoviral vector-mediated infection. We first measured the redox capacity of hucMSC-Trx-1 with an antioxidant capacity (T-AOC assay, a hydrogen peroxide (H2O2 content determination assay in vivo, a H2O2-induced oxidation hemolysis assay, and a lipid peroxidation assay in vitro. Then, we measured survival time, the protection of the hematopoietic system, and the regulation of inflammation in important organs in three treatment groups of NOD/SCID mice (treated with hucMSC-Trx-1, with hucMSC, and with saline that were exposed to 4.5 Gy (60Co-γ-ray radiation. The hucMSC-Trx-1 group achieved superior antioxidation results, protecting bone marrow hematopoietic stem cells (Lin(-CD117(+: hucMSC-Trx-1 vs. hucMSC, P<0.05; hucMSC-Trx-1 vs. NS, P<0.01, promoting the formation of red blood cells and hemoglobin (hucMSC-Trx-1 vs. hucMSC or NS, P<0.05, reducing inflammation and damage in important organs (Bone marrow and lung: hucMSC-Trx-1 vs. NS, P<0.01; hucMSC-Trx-1 vs. hucMSC, P<0.05. Liver and intestine: hucMSC-Trx-1 vs. NS, P<0.05; hucMSC-Trx-1 vs. hucMSC, P<0.05, and prolonging survival (hucMSC-Trx-1 vs. hucMSC or NS, P<0

  13. Centrifugal Compressor Aeroelastic Analysis Code

    Science.gov (United States)

    Keith, Theo G., Jr.; Srivastava, Rakesh

    2002-01-01

    Centrifugal compressors are very widely used in the turbomachine industry where low mass flow rates are required. Gas turbine engines for tanks, rotorcraft and small jets rely extensively on centrifugal compressors for rugged and compact design. These compressors experience problems related with unsteadiness of flowfields, such as stall flutter, separation at the trailing edge over diffuser guide vanes, tip vortex unsteadiness, etc., leading to rotating stall and surge. Considerable interest exists in small gas turbine engine manufacturers to understand and eventually eliminate the problems related to centrifugal compressors. The geometric complexity of centrifugal compressor blades and the twisting of the blade passages makes the linear methods inapplicable. Advanced computational fluid dynamics (CFD) methods are needed for accurate unsteady aerodynamic and aeroelastic analysis of centrifugal compressors. Most of the current day industrial turbomachines and small aircraft engines are designed with a centrifugal compressor. With such a large customer base and NASA Glenn Research Center being, the lead center for turbomachines, it is important that adequate emphasis be placed on this area as well. Currently, this activity is not supported under any project at NASA Glenn.

  14. Mesenchymal Stem Cells (MSC Regulate Activation of Granulocyte-Like Myeloid Derived Suppressor Cells (G-MDSC in Chronic Myeloid Leukemia Patients.

    Directory of Open Access Journals (Sweden)

    Cesarina Giallongo

    Full Text Available It is well known that mesenchymal stem cells (MSC have a role in promotion of tumor growth, survival and drug-resistance in chronic myeloid leukemia (CML. Recent reports indicated that a subpopulation of myeloid cells, defined as granulocyte-like myeloid-derived suppressor cells (G-MDSC is increased in these patients. So far, the role of MSC in MDSC expansion and activation into the BM microenvironment remains unexplored. To address this question, here we use a specific experimental model in vitro, co-culturing MSC with peripheral blood mononucleated cells (PBMC from normal individuals, in order to generate MSC-educated G-MDSC. Although MSC of healthy donors (HD and CML patients were able to generate the same amount of MDSC, only CML-MSC-educated G-MDSC exhibited suppressive ability on autologous T lymphocytes. In addition, compared with HD-MSC, CML-MSC over-expressed some immunomodulatory factors including TGFβ, IL6 and IL10, that could be involved in MDSC activation. CML-MSC-educated G-MDSC expressed higher levels of ARG1, TNFα, IL1β, COX2 and IL6 than G-MDSC isolated from co-culture with HD-MSC. Our data provide evidence that CML-MSC may play a critical role in tumor microenvironment by orchestrating G-MDSC activation and regulating T lymphocytes-mediated leukemia surveillance, thus contributing to CML immune escape.

  15. Mesenchymal Stem Cells (MSC) Regulate Activation of Granulocyte-Like Myeloid Derived Suppressor Cells (G-MDSC) in Chronic Myeloid Leukemia Patients.

    Science.gov (United States)

    Giallongo, Cesarina; Romano, Alessandra; Parrinello, Nunziatina Laura; La Cava, Piera; Brundo, Maria Violetta; Bramanti, Vincenzo; Stagno, Fabio; Vigneri, Paolo; Chiarenza, Annalisa; Palumbo, Giuseppe Alberto; Tibullo, Daniele; Di Raimondo, Francesco

    2016-01-01

    It is well known that mesenchymal stem cells (MSC) have a role in promotion of tumor growth, survival and drug-resistance in chronic myeloid leukemia (CML). Recent reports indicated that a subpopulation of myeloid cells, defined as granulocyte-like myeloid-derived suppressor cells (G-MDSC) is increased in these patients. So far, the role of MSC in MDSC expansion and activation into the BM microenvironment remains unexplored. To address this question, here we use a specific experimental model in vitro, co-culturing MSC with peripheral blood mononucleated cells (PBMC) from normal individuals, in order to generate MSC-educated G-MDSC. Although MSC of healthy donors (HD) and CML patients were able to generate the same amount of MDSC, only CML-MSC-educated G-MDSC exhibited suppressive ability on autologous T lymphocytes. In addition, compared with HD-MSC, CML-MSC over-expressed some immunomodulatory factors including TGFβ, IL6 and IL10, that could be involved in MDSC activation. CML-MSC-educated G-MDSC expressed higher levels of ARG1, TNFα, IL1β, COX2 and IL6 than G-MDSC isolated from co-culture with HD-MSC. Our data provide evidence that CML-MSC may play a critical role in tumor microenvironment by orchestrating G-MDSC activation and regulating T lymphocytes-mediated leukemia surveillance, thus contributing to CML immune escape.

  16. design, construction and measured performance of a single-stage

    African Journals Online (AJOL)

    2012-11-03

    Nov 3, 2012 ... Abstract. The design philosophy, construction and measured performances of a single stage, single entry centrifugal pump .... the tachometer spindle to be held against a recess in the motor shaft. The constructed centrifugal ...

  17. Ultra scaledown to predict filtering centrifugation of secreted antibody fragments from fungal broth.

    Science.gov (United States)

    Boulding, N; Yim, S S S; Keshavarz-Moore, E; Ayazi Shamlou, P; Berry, M

    2002-08-20

    Extracellularly expressed anti-hen egg lysozyme single-chain antibody fragments (scFv) produced by Aspergillus awamori were recovered using filtering centrifugation. Two filtering centrifuges with 0.5- and 30-L capacities were used to represent laboratory- and pilot-scale equipment, respectively. Critical regime analysis using the computational fluid dynamics (CFD) technique provided information about the local energy dissipation rates in both units. Experimental data indicated loss of scFv activity for energy dissipation rates above about 2.0 x 10(4) W kg(-1). This loss of activity increased in the presence of gas-liquid interfaces during filtering centrifugation. An ultra scaledown filtering centrifuge with a maximum working volume of 35 mL was designed to mimic the operating conditions identified by the critical regime analysis for the laboratory- and pilot-plant-scale units. The recovered scFv activity levels and the separation performance of the three units were comparable when operated at equal maximum energy dissipation rates. Copyright 2002 Wiley Periodicals, Inc.

  18. The magnetic centrifugal mass filter

    International Nuclear Information System (INIS)

    Fetterman, Abraham J.; Fisch, Nathaniel J.

    2011-01-01

    Mass filters using rotating plasmas have been considered for separating nuclear waste and spent nuclear fuel. We propose a new mass filter that utilizes centrifugal and magnetic confinement of ions in a way similar to the asymmetric centrifugal trap. This magnetic centrifugal mass filter is shown to be more proliferation resistant than present technology. This filter is collisional and produces well confined output streams, among other advantages.

  19. The magnetic centrifugal mass filter

    Energy Technology Data Exchange (ETDEWEB)

    Fetterman, Abraham J.; Fisch, Nathaniel J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540 (United States)

    2011-09-15

    Mass filters using rotating plasmas have been considered for separating nuclear waste and spent nuclear fuel. We propose a new mass filter that utilizes centrifugal and magnetic confinement of ions in a way similar to the asymmetric centrifugal trap. This magnetic centrifugal mass filter is shown to be more proliferation resistant than present technology. This filter is collisional and produces well confined output streams, among other advantages.

  20. Theoretical investigations on plasma centrifuges

    International Nuclear Information System (INIS)

    Hong, S.H.

    1978-01-01

    The theoretical analysis of the steady-state dynamics of plasma centrifuges is dealt with to understand the physics of rotating plasmas and their feasibility for isotope separation. The centrifuge systems under consideration employ cylindrical gas discharge chambers with externally-applied axial magnetic fields. The cathode and anode are symmetric about the cylinder axis and arranged in such a way for each system, i.e., (1) two ring electrodes of different radii in the chamber end plates or (2) two ring electrodes embedded in the mantle of the cylinder. They produce converging and/or diverging current density field lines, which intersect the external magnetic field under a nonvanishing angle. The associated Lorentz forces set the plasma, which is produced through an electrical discharge, into rotation around the cylinder axis. Three boundary-value problems for the coupled partial differential equations of the centrifuge fields are formulated, respectively, on the basis of the magnetogasdynamic equations. The electric field, electrostatic potential, current density, induced magnetic field, and velocity distributions are discussed in terms of the Hartmann number, the Hall coefficient, and the magnetic Reynolds number. The plasma centrifuge analyses presented show that the speeds of plasma rotation up to the order of 10 4 m/sec are achievable at typical conditions. The associated centrifugal forces produce a significant spatial isotope separation, which is somewhat reduced in the viscous boundary layers at the centrifuge walls. The speeds of plasma rotation increase with increasing Hartmann number and Hall coefficient. For small Hall coefficient, the induced azimuthal magnetic field does not affect the plasma rotation. For large volumes of rotating isotope mixtures, a multidischarge centrifuge can be constructed by setting up a large number of centrifuge systems in series

  1. 21 CFR 864.5350 - Microsedimentation centrifuge.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Microsedimentation centrifuge. 864.5350 Section 864.5350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... § 864.5350 Microsedimentation centrifuge. (a) Identification. A microsedimentation centrifuge is a...

  2. Uranium enrichment by gas centrifuge

    International Nuclear Information System (INIS)

    Heriot, I.D.

    1988-01-01

    After recalling the physical principles and the techniques of centrifuge enrichment the report describes the centrifuge enrichment programmes of the various countries concerned and compares this technology with other enrichment technologies like gaseous diffusion, laser, aerodynamic devices and chemical processes. The centrifuge enrichment process is said to be able to replace with advantage the existing enrichment facilities in the short and medium term. Future prospects of the process are also described, like recycled uranium enrichment and economic improvements; research and development needs to achieve the economic prospects are also indicated. Finally the report takes note of the positive aspect of centrifuge enrichment as far as safeguards and nuclear safety are concerned. 27 figs, 113 refs

  3. Centrifugation speed affects light transmission aggregometry.

    Science.gov (United States)

    Merolla, M; Nardi, M A; Berger, J S

    2012-02-01

    Light transmission aggregometry (LTA) is considered the gold standard for investigating platelet activity ex vivo. However, LTA protocols are not standardized, and differences in LTA procedure are a potential source of variance in results. Centrifugation speed is an essential component of platelet preparation in LTA, has yet to be standardized, and may affect platelet aggregation results. We sought to investigate the effect of relative centrifugal force (RCF) intensity on LTA results. Ten healthy controls had venous blood drawn and centrifuged at 150, 200, 300, and 500 g for 10 min. Cell counts in whole blood and platelet-rich plasma (PRP) were measured using a hematology analyzer. LTA was performed using 1.0 μm adenosine diphosphate (ADP) and 0.4 μm epinephrine as an agonist. Aggregation (%) was compared at 60, 120, 180, and 300 s and at maximum aggregation. Centrifugation speed was associated with decreasing platelet count (P centrifuge RCF at 60, 120, 180, 300 s and at maximum aggregation (P centrifugation speed in the interpretation of LTA results, supporting the need for standardization of centrifugation RCF in LTA protocols. © 2011 Blackwell Publishing Ltd.

  4. β3-Adrenergic Regulation of EPC Features Through Manipulation of the Bone Marrow MSC Niche.

    Science.gov (United States)

    Vafaei, Rana; Nassiri, Seyed Mahdi; Siavashi, Vahid

    2017-12-01

    Mesenchymal stem cells (MSCs) reside in a specific niche in the bone marrow, however, biological features of this niche are still not fully understood. Given the interactions of MSCs with endothelial cells in different tissues, bone marrow MSC niche may influence the biological features of endothelial progenitor cells (EPCs). To understand the role of the sympathetic nervous system in regulation of the MSC niche, we examined whether the manipulation of the MSC niche via β3-adrenergic signals will affect EPC features. A selective β3 agonist (BRL37344) or a β3 antagonist (SR59230A) was administered in mice for 2 weeks to determine the potential effects of these regimens on the population of CD133 + stem cells in the bone marrow. Then, bone marrow-derived MSCs and EPCs were harvested and expanded from the mice to examine the effect of changes in the MSC niche on EPC features. Improved MSC colony forming potency with increased bone marrow stromal cell-derived factor 1 (SDF-1) (also known as C-X-C motif chemokine 12 [CXCL12]) expression was shown as a result of intensification of the bone marrow adrenergic signals through BRL37344 injection. On the other hand, the blockage of these signals limited the expression level of SDF-1 and resulted in bone marrow enrichment of CD133 + cells. Manipulation of the MSC niche and decreased SDF-1 expression via SR59230A injection also prompted EPCs to form more colonies with augmented proliferation and differentiation capacity. Overall, our results indicate that the β3-adrenergic signals regulate the MSC niche, thereby resulting in modulation of EPC biological features. J. Cell. Biochem. 118: 4753-4761, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Effects of platelet rich plasma and chondrocyte co-culture on MSC chondrogenesis, hypertrophy and pathological responses

    OpenAIRE

    Ramezanifard, Rouhallah; Kabiri, Mahboubeh; Hanaee Ahvaz, Hana

    2017-01-01

    Regarding the inadequate healing capability of cartilage tissue, cell-based therapy is making the future of cartilage repair and regeneration. Mesenchymal stem cells (MSC) have shown great promise in cartilage regeneration. However, a yet-unresolved issue is the emergence of hypertrophic and pathologic markers during in vitro MSC chondrogenesis. Articular chondrocytes (AC) can suppress the undesired hypertrophy when co-cultured with MSC. On the other hand, platelet rich plasma (PRP), is consi...

  6. MSc Agriculture students working with ex-campus stakeholders

    DEFF Research Database (Denmark)

    Langer, Vibeke; Lund, Mogens; Bendevis, Mira Arpe

    2014-01-01

    both on BSc and MSc level. For many students this results in concerns whether their knowledge, skills and competencies are sufficient when confronted with reality in a job, i.e. in a lack of professional confidence. Therefore when revising the program we focused on competences in contextualizing...

  7. Confirming the Revised C-Terminal Domain of the MscL Crystal Structure

    OpenAIRE

    Maurer, Joshua A.; Elmore, Donald E.; Clayton, Daniel; Xiong, Li; Lester, Henry A.; Dougherty, Dennis A.

    2008-01-01

    The structure of the C-terminal domain of the mechanosensitive channel of large conductance (MscL) has generated significant controversy. As a result, several structures have been proposed for this region: the original crystal structure (1MSL) of the Mycobacterium tuberculosis homolog (Tb), a model of the Escherichia coli homolog, and, most recently, a revised crystal structure of Tb-MscL (2OAR). To understand which of these structures represents a physiological conformation, we measured the ...

  8. European MSc Programs in Nuclear Sciences - To meet the Need of Stakeholders

    International Nuclear Information System (INIS)

    Salbu, Brit; Skipperud, Lindis; Priest, Nick; Garelick, Hemda; Tamponnet, Christian; Mitchell, Peter

    2009-01-01

    A stakeholder needs assessment, carried out under the EU-EURAC and EU-ENEN II projects, clearly showed that, at the European level, there are a significant and constant need for post-graduates with skills in radiochemistry, radioecology, radiation dosimetry and environmental modelling and a smaller, but still important, demand for radiobiologists and bio-modellers. Most of these needs are from government organizations. If only the nuclear industry is considered, then the largest demand is for radiochemists and radiation protection dosimetrists. Given this spectrum of need and existing capacity in the areas of radiobiology it was concluded that the needs identified would be most efficiently met by three new degree programs: European MSc Radiation Protection European MSc Analytical Radiochemistry European MSc Radioecology. All three master programs would be developed using the framework provided by the Bologna Convention and the lecturing could be shared among specialist Scientists within a network of collaborating universities. Therefore, educational plans have been developed for the above MSc degrees. These plans envisage each degree comprising three modules that are common to all the degrees (3x10 ECTS credits), three specialist modules (3x10 ECTS credits) and a research project (1x60 ECTS credits). The courses should be aimed, not only to fill the identified European postgraduate education gap in radiological sciences, but also to provide a modular structure that is easily accessed by stakeholders for CPD training. It is anticipated that the European Masters will meet the academic training requirements of qualified 'experts', as defined by the European Commission and the IAEA. At the Norwegian University of Life Sciences (UMB) a pilot MSc in Radioecology has successfully been initiated in collaboration with UK and France.

  9. European MSc Programs in Nuclear Sciences-To meet the need of stakeholders

    International Nuclear Information System (INIS)

    Skipperud, L.; Salbu, B.; Priest, N.; Garelick, H.; Tamponnet, C.; Abbott, A.; Mitchell, P.

    2011-01-01

    A stakeholder needs assessment, carried out under the EU-EURAC and EU-ENEN-II projects, clearly showed that, at the European level, there are a significant and constant need for post-graduates with skills in radiochemistry, radioecology, radiation dosimetry and environmental modelling and a smaller, but still important, demand for radiobiologists and bio-modellers. Most of these needs are from government organizations. If only the nuclear industry is considered, then the largest demand is for radio chemists and radiation protection dosimetry experts. Given this spectrum of need and existing capacity in the areas of radiobiology it was concluded that the needs identified would be most efficiently met by three new degree programs: ·European MSc Radiation Protection, ·European MSc Analytical Radiochemistry, ·European MSc Radioecology. All three master programs would be developed using the framework provided by the Bologna Convention and the lecturing could be shared among specialist Scientists within a network of collaborating universities. Therefore, educational plans have been developed for the above MSc degrees. These plans envisage each degree comprising three modules that are common to all the degrees (3 x 10 ECTS credits), three specialist modules (3 x 10 ECTS credits) and a research project (1 x 60 ECTS credits). The courses should be aimed, not only to fill the identified European post-graduate education gap in radiological sciences, but also to provide a modular structure that is easily accessed by stakeholders for CPD training. It is anticipated that the European Masters will meet the academic training requirements of qualified experts', as defined by the European Commission and the IAEA. At the Norwegian University of Life Sciences (UMB) a pilot MSc in Radioecology has successfully been initiated in collaboration with UK and France.

  10. M.Sc. in Civil and Structural Engineering

    DEFF Research Database (Denmark)

    The following pages contain a list of project ideas proposed by the scientific staff at the Department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalogue may form the basis for long and short master projects as well as regular 3rd...... semester projects at the M.Sc. programme in Civil and Structural Engineering....

  11. M.Sc. in Civil and Structural Engineering

    DEFF Research Database (Denmark)

    Clausen, Johan

    The report contain a list of project ideas proposed by the scientific staff at the Department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalogue may form the basis for long and short candidate projects as well as regular 3rd semester...... projects at the M.Sc. programme in Civil and Structural Engineering....

  12. M.Sc. in Civil and Structural Engineering

    DEFF Research Database (Denmark)

    The catalogue contain a list of project ideas proposed by the scientific staff at the Department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalogue may form the basis for long and short candidate projects as well as regular 3rd semester...... projects at the M.Sc. programme in Civil and Structural Engineering....

  13. M.Sc. in Civil and Structural Engineering

    DEFF Research Database (Denmark)

    This catalogue contains a list of project ideas proposed by the scientific staff at the Department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalogue may form the basis for long and short candidate projects as well as regular 3rd...... semester projects at the M.Sc. programme in Civil and Structural Engineering....

  14. CFD simulation of centrifugal cells washers.

    Science.gov (United States)

    Kellet, Beth E; Binbing, Han; Dandy, David S; Wickramasinghe, S Ranil

    2004-01-01

    The feasibility of using computational fluid dynamics to guide the design of better centrifuges for processing shed blood is explored here. The velocity field and the rate of protein removal from the shed blood have been studied. The results indicate that computational fluid dynamics could help screen preliminary centrifuge bowl designs thus reducing the number of initial experimental tests required when developing new centrifuge bowls. Though the focus of this work is on washing shed blood the methods developed here are applicable to the design of centrifuge bowls for other blood processing applications.

  15. Comparison of MSC-Neurogenin1 administration modality in MCAO rat model

    Directory of Open Access Journals (Sweden)

    Shin Dong Hoon

    2016-12-01

    Full Text Available Intracerebral (IC grafting of mesenchymal stem cells (MSCs is not currently used in humans due to its potential complications. On the other hand, intra-arterial (IA administration can be facilitated for engrafting of intensifed MSCs in the injured human brain. The study is designed to compare the two methods of MSC administration using IA and IC routes through the parameters of behavior, infarct volume, cell distribution, and MSC identification. An ischemic stroke model was generated in Sprague Dawley male rats. This experiment used MSCs/Ngn1 that express Neurogenin1 (Ngn1 to ensure grafted MSC maintenance. MSCs/Ngn1 or normal saline was administrated via the IC or IA route on day 3. All animals were randomly assigned into four groups (five rats in each group: IC-control, IA-control, IC-MSCs/Ngn1, or IA-MSCs/Ngn1. Motor behaviors, infarct volume, and distribution of superparamagnetic iron oxide (SPIO-labeled cells on magnetic resonance imaging (MRI were compared from each group. There were no baseline differencess in motor behaviors or infarct volume between IC-MSCs/Ngn1 and IA-MSCs/Ngn1. Hovever, the IA-MSCs/Ngn1 group showed the greatest recovery on Rotarod testing and adhesive removal tests (p = 0.003 and p = 0.009 vs. IC-MSCs/Ngn1, respectively. The IA-MSCs/Ngn1 group also had more evenly distributed SPIO-labeled cells on MRI. The results suggest that IA administration is likely to be benefcial for humans based on its ability to improve behavioral outcomes and ensure even MSC engrafting.

  16. Progress in ultra-centrifuge enrichment technology

    International Nuclear Information System (INIS)

    Paul Dawson

    2006-01-01

    Urenco have undertaken a continuous development programme in centrifuge technology for over 35 years. This has seen development from sub-critical machines in the mid 1970's through to the company's world leading TC12 supercritical centrifuge, which has been deployed on a large-scale basis over the last decade. The latest centrifuge to emerge from this programme is Urenco's sixth generation centrifuge, the TC21, which will be commercially deployed from mid-2007 onwards. In recent times Urenco has vested its centrifuge technology in Enrichment Technology Company (ETC) as a vehicle to enable the use of this advanced technology by other operators for commercial purposes. This paper reviews why Urenco and ETC believe this technology represents the best choice for creating new global commercial enrichment capacity and its future development prospects. (author)

  17. Granulocyte-like myeloid derived suppressor cells (G-MDSC) are increased in multiple myeloma and are driven by dysfunctional mesenchymal stem cells (MSC).

    Science.gov (United States)

    Giallongo, Cesarina; Tibullo, Daniele; Parrinello, Nunziatina L; La Cava, Piera; Di Rosa, Michelino; Bramanti, Vincenzo; Di Raimondo, Cosimo; Conticello, Concetta; Chiarenza, Annalisa; Palumbo, Giuseppe A; Avola, Roberto; Romano, Alessandra; Di Raimondo, Francesco

    2016-12-27

    Granulocytic-Myeloid-derived suppressor cells (G-MDSC) are increased in Multiple Myeloma (MM) patients but the mechanisms of G-MDSC generation are still unknown. There are many evidences of the role of mesenchymal stem cells (MSC) in promoting MM cell growth, survival and drug-resistance. We here used a specific experimental model in vitro to evaluate the ability of MSC to induce G-MDSC. We found that although MSC derived from healthy donors (HD), MGUS and MM were able to generate the same amount of MDSC, only MM-MSC-educated G-MDSC exhibited suppressive ability. In addition, in comparison with MSC derived from HD, MM-MSC produce higher amount of immune-modulatory factors that could be involved in MDSC induction. Compared to G-MDSC obtained from co-culture models with MSC from healthy subjects, both MGUS and MM-MSC-educated G-MDSC showed increase of immune-modulatory factors. However, only MM-MSC educated G-MDSC 1) up-regulated immune-suppressive factors as ARG1 and TNFα, 2) expressed higher levels of PROK2, important in angiogenesis and inflammatory process, and 3) showed ability to digest bone matrix.Our data demonstrate that MM-MSC are functionally different from healthy subjects and MGUS-MSC, supporting an evolving concept regarding the contribution of MM-MSC to tumor development and progression.

  18. Review of Signaling Pathways Governing MSC Osteogenic and Adipogenic Differentiation

    Directory of Open Access Journals (Sweden)

    Aaron W. James

    2013-01-01

    Full Text Available Mesenchymal stem cells (MSC are multipotent cells, functioning as precursors to a variety of cell types including adipocytes, osteoblasts, and chondrocytes. Between osteogenic and adipogenic lineage commitment and differentiation, a theoretical inverse relationship exists, such that differentiation towards an osteoblast phenotype occurs at the expense of an adipocytic phenotype. This balance is regulated by numerous, intersecting signaling pathways that converge on the regulation of two main transcription factors: peroxisome proliferator-activated receptor-γ (PPARγ and Runt-related transcription factor 2 (Runx2. These two transcription factors, PPARγ and Runx2, are generally regarded as the master regulators of adipogenesis and osteogenesis. This review will summarize signaling pathways that govern MSC fate towards osteogenic or adipocytic differentiation. A number of signaling pathways follow the inverse balance between osteogenic and adipogenic differentiation and are generally proosteogenic/antiadipogenic stimuli. These include β-catenin dependent Wnt signaling, Hedgehog signaling, and NELL-1 signaling. However, other signaling pathways exhibit more context-dependent effects on adipogenic and osteogenic differentiation. These include bone morphogenic protein (BMP signaling and insulin growth factor (IGF signaling, which display both proosteogenic and proadipogenic effects. In summary, understanding those factors that govern osteogenic versus adipogenic MSC differentiation has significant implications in diverse areas of human health, from obesity to osteoporosis to regenerative medicine.

  19. Compatibility of the Space Station Freedom life sciences research centrifuge with microgravity requirements

    Science.gov (United States)

    Hasha, Martin D.

    1990-01-01

    NASA is developing a Life Sciences Centrifuge Facility for Space Station Freedom. In includes a 2.5-meter artificial gravity Bioresearch Centrifuge (BC), which is perhaps the most critical single element in the life sciences space research program. It rotates continuously at precise selectable rates, and utilizes advanced reliable technologies to reduce vibrations. Three disturbance types are analyzed using a current Space Station Freedom dynamic model in the 0.0 to 5.0 Hz range: sinusoidal, random, and transient. Results show that with proper selection of proven design techniques, BC vibrations are compatible with requirements.

  20. Empirical Design Considerations for Industrial Centrifugal Compressors

    Directory of Open Access Journals (Sweden)

    Cheng Xu

    2012-01-01

    Full Text Available Computational Fluid Dynamics (CFD has been extensively used in centrifugal compressor design. CFD provides further optimisation opportunities for the compressor design rather than designing the centrifugal compressor. The experience-based design process still plays an important role for new compressor developments. The wide variety of design subjects represents a very complex design world for centrifugal compressor designers. Therefore, some basic information for centrifugal design is still very important. The impeller is the key part of the centrifugal stage. Designing a highly efficiency impeller with a wide operation range can ensure overall stage design success. This paper provides some empirical information for designing industrial centrifugal compressors with a focus on the impeller. A ported shroud compressor basic design guideline is also discussed for improving the compressor range.

  1. Centrifuge Health Monitoring of the 50gTon beam centrifuge at the University of Sheffield

    OpenAIRE

    Cox, C.M.; Black, J.A.; Hakhamanshi, M.; Baker, N.

    2016-01-01

    In order to fully understand scientific test data it is crucial that we first understand the back-ground centrifuge operational environment and its variation with time and centrifugal acceleration. For exam-ple, changes in ambient air temperature or relative humidity in the centrifuge chamber during operation can have a significant impact on the evaporation levels of water from the surface of a clay model. It is vital to un-derstand these temporal changes in order to mitigate drying out of th...

  2. Perceived radial translation during centrifugation

    NARCIS (Netherlands)

    Bos, J.E.; Correia Grácio, B.J.

    2015-01-01

    BACKGROUND: Linear acceleration generally gives rise to translation perception. Centripetal acceleration during centrifugation, however, has never been reported giving rise to a radial, inward translation perception. OBJECTIVE: To study whether centrifugation can induce a radial translation

  3. Comparison Virtual Landing Gear Drop Test for Commuter Aircraft Utilize MSC ADAMS And Solidworks Motion Analysis

    Science.gov (United States)

    Hidayat, Dony; Istiyanto, Jos; Agus Sumarsono, Danardono

    2018-04-01

    Loads at main landing gear while touchdown impact is function of aircraft weight and ground reaction load factor. In regulation states ground reaction load factor at Vsink = 3.05 m/s is below 3. Contact/impact force from simulation using MSC ADAMS is 94680 N, while using Solidworks Motion Analysis is 97691 N. The difference between MSC ADAMS and Solidworks Motion Analysis is 3.08%. The ground reaction load factor in MSC ADAMS is 2.78 while in Solidworks Motion Analysis is 2.87.

  4. The Advanced Gas Centrifuge program

    International Nuclear Information System (INIS)

    Riepe, R.

    1984-01-01

    Although the gas centrifuge process for uranium enrichment is often referred to as a ''new technology,'' it has been under development for approximately 25 years to bring it to its current state of deployment. Centrifuges are now being installed in a new gas centrifuge enrichment plant (GCEP) at Portsmouth, Ohio. The objective of this new plant was to provide additional U.S. uranium enrichment capacity at a production cost comparable to the U.S. diffusion process but requiring much less power per separative work unit (SWU) produced. The current, commercial scale centrifuge technology being installed meets that objective. The objective for new U.S. enrichment capacity has changed. The objective is not to provide more SWUs but to provide cheaper SWUs. The objective is to make the U.S. uranium enrichment enterprise competitive on the international market. Where the U.S. at one time supplied virtually all of the free world SWU demand, the U.S. market share has now dropped to approximately 35% of the foreign free world market. The Advanced Gas Centrifuge (AGC) program provides an avenue for making the U.S. the economically attractive, reliable enrichment supplier

  5. Modeling of UF{sub 6} enrichment with gas centrifuges for nuclear safeguards activities

    Energy Technology Data Exchange (ETDEWEB)

    Mercurio, G.; Peerani, P.; Richir, P.; Janssens, W.; Eklund, G. [European Commission, Joint Research Centre, Institute for Transuranium Elements Via Fermi, 2749-TP181,20127 Ispra (Italy)

    2012-09-26

    The physical modeling of uranium isotopes ({sup 235}U, {sup 238}U) separation process by centrifugation of is a key aspect for predicting the nuclear fuel enrichment plant performances under surveillance by the Nuclear Safeguards Authorities. In this paper are illustrated some aspects of the modeling of fast centrifuges for UF{sub 6} gas enrichment and of a typical cascade enrichment plant with the Theoretical Centrifuge and Cascade Simulator (TCCS). The background theory for reproducing the flow field characteristics of a centrifuge is derived from the work of Cohen where the separation parameters are calculated using the solution of a differential enrichment equation. In our case we chose to solve the hydrodynamic equations for the motion of a compressible fluid in a centrifugal field using the Berman - Olander vertical velocity radial distribution and the solution was obtained using the Matlab software tool. The importance of a correct estimation of the centrifuge separation parameters at different flow regimes, lies in the possibility to estimate in a reliable way the U enrichment plant performances, once the separation external parameters are set (feed flow rate and feed, product and tails assays). Using the separation parameters of a single centrifuge allow to determine the performances of an entire cascade and, for this purpose; the software Simulink was used. The outputs of the calculation are the concentrations (assays) and the flow rates of the enriched (product) and depleted (tails) gas mixture. These models represent a valid additional tool, in order to verify the compliance of the U enrichment plant operator declarations with the 'on site' inspectors' measurements.

  6. Extraction of soil solution by drainage centrifugation-effects of centrifugal force and time of centrifugation on soil moisture recovery and solute concentration in soil moisture of loess subsoils.

    Science.gov (United States)

    Fraters, Dico; Boom, Gerard J F L; Boumans, Leo J M; de Weerd, Henk; Wolters, Monique

    2017-02-01

    The solute concentration in the subsoil beneath the root zone is an important parameter for leaching assessment. Drainage centrifugation is considered a simple and straightforward method of determining soil solution chemistry. Although several studies have been carried out to determine whether this method is robust, hardly any results are available for loess subsoils. To study the effect of centrifugation conditions on soil moisture recovery and solute concentration, we sampled the subsoil (1.5-3.0 m depth) at commercial farms in the loess region of the Netherlands. The effect of time (20, 35, 60, 120 and 240 min) on recovery was studied at two levels of the relative centrifugal force (733 and 6597g). The effect of force on recovery was studied by centrifugation for 35 min at 117, 264, 733, 2932, 6597 and 14,191g. All soil moisture samples were chemically analysed. This study shows that drainage centrifugation offers a robust, reproducible and standardised way for determining solute concentrations in mobile soil moisture in silt loam subsoils. The centrifugal force, rather than centrifugation time, has a major effect on recovery. The maximum recovery for silt loams at field capacity is about 40%. Concentrations of most solutes are fairly constant with an increasing recovery, as most solutes, including nitrate, did not show a change in concentration with an increasing recovery.

  7. Valve for gas centrifuges

    Science.gov (United States)

    Hahs, Charles A.; Burbage, Charles H.

    1984-01-01

    The invention is a pneumatically operated valve assembly for simultaneously (1) closing gas-transfer lines connected to a gas centrifuge or the like and (2) establishing a recycle path between two of the lines so closed. The valve assembly is especially designed to be compact, fast-acting, reliable, and comparatively inexpensive. It provides large reductions in capital costs for gas-centrifuge cascades.

  8. Centrifuge facilities at Technical University of Denmark

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane; Krogsbøll, Anette Susanne; Hededal, Ole

    2008-01-01

    The geotechnical group at the Danish Technical University (DTU) operates a geotechnical beam centrifuge. The centrifuge was build in 1976 and has been upgraded through the years, latest with onboard data and control systems. The centrifuge concept involves an increased gravity field in which...... the physical model is placed and tested. The capabilities of the centrifuge at DTU makes it possible to obtain a scale factor of 75-85 in the tests which equals a soil volume in prototype scale of ø40m and a depth of 36 m. The centrifuge facilities at DTU have through the years been used for testing various...... geotechnical issues, such as suction anchors, tension piles in clay, active earth pressures on sheet piles and group effects for lateral loaded piles. The paper describes physical modelling in general, the centrifuge, present setups and shows samples of obtained results....

  9. On the enrichment of low-abundant isotopes of light chemical elements by gas centrifuges

    International Nuclear Information System (INIS)

    Borisevich, V.D.; Morozov, O.E.; Zaozerskiy, Yu.P.; Shmelev, G.M.; Shipilov, Yu.D.

    2000-01-01

    A brief review of the main areas for the application of the isotopes 15 N and 13 C is made. Separation of the nitrogen isotopes in a single gas centrifuge in the form of pure nitrogen, ammonia, and trifluoride of nitrogen as well as the carbon isotopes in the form of carbon dioxide has been studied by means of numerical simulation. The parameters of the centrifugal machine investigated were close to the parameters of the Iguassu machine. The dependence of the efficiency criterion versus the basic parameters of the separation process has been explored in the computational experiments. Comparisons of the calculated results with the experimental data have shown good agreement. The results obtained have demonstrated the possibility of using gas centrifuge technology to enrich successfully the low-abundant isotopes of light chemical elements

  10. Magnetic resonance imaging of single co-labeled mesenchymal stromal cells after intracardial injection in mice

    International Nuclear Information System (INIS)

    Salamon, J.; Adam, G.; Peldschus, K.; Wicklein, D.; Schumacher, U.; Didie, M.; Lange, C.

    2014-01-01

    Purpose: The aim of this study was to establish co-labeling of mesenchymal stromal cells (MSC) for the detection of single MSC in-vivo by MRI and histological validation. Materials and Methods: Mouse MSC were co-labeled with fluorescent iron oxide micro-particles and carboxyfluorescein succinimidyl ester (CFSE). The cellular iron content was determined by atomic absorption spectrometry. Cell proliferation and expression of characteristic surface markers were determined by flow cytometry. The chondrogenic differentiation capacity was assessed. Different amounts of cells (n1 = 5000, n2 = 15 000, n3 = 50 000) were injected into the left heart ventricle of 12 mice. The animals underwent sequential MRI on a clinical 3.0T scanner (Intera, Philips Medical Systems, Best, The Netherlands). For histological validation cryosections were examined by fluorescent microscopy. Results: Magnetic and fluorescent labeling of MSC was established (mean cellular iron content 23.6 ± 3 pg). Flow cytometry showed similar cell proliferation and receptor expression of labeled and unlabeled MSC. Chondrogenic differentiation of labeled MSC was verified. After cell injection MRI revealed multiple signal voids in the brain and fewer signal voids in the kidneys. In the brain, an average of 4.6 ± 1.2 (n1), 9.0 ± 3.6 (n2) and 25.0 ± 1.0 (n3) signal voids were detected per MRI slice. An average of 8.7 ± 3.1 (n1), 22.0 ± 6.1 (n2) and 89.8 ± 6.5 (n3) labeled cells per corresponding stack of adjacent cryosections could be detected in the brain. Statistical correlation of the numbers of MRI signal voids in the brain and single MSC found by histology revealed a correlation coefficient of r = 0.91. Conclusion: The study demonstrates efficient magnetic and fluorescent co-labeling of MSC and their detection on a single cell level in mice by in-vivo MRI and histology. The described techniques may broaden the methods for in-vivo tracking of MSC. (orig.)

  11. Some engineering considerations when designing centrifuge enrichment plants

    International Nuclear Information System (INIS)

    Edwards, T.T.

    1982-01-01

    A review is given of the three main areas where flexibility is needed in the design of centrifuge enrichment plants. These are: the need to cope with market requirements, the limitations imposed by currently available centrifuges and ever advancing centrifuge technology. Details of BNFL's experience with centrifuge enrichment at Capenhurst are presented. (U.K.)

  12. Centrifuge treatment of coal tar

    Energy Technology Data Exchange (ETDEWEB)

    L.A. Kazak; V.Z. Kaidalov; L.F. Syrova; O.S. Miroshnichenko; A.S. Minakov [Giprokoks, the State Institute for the Design of Coke-Industry Enterprises, Kharkov (Ukraine)

    2009-07-15

    New technology is required for the removal of water and heavy fractions from regular coal tar. Centrifuges offer the best option. Purification of coal tar by means of centrifuges at OAO NLMK permits the production of pitch coke or electrode pitch that complies with current standards.

  13. Centrifuges and inertial shear forces

    NARCIS (Netherlands)

    Loon, van J.J.W.A.; Folgering, H.T.E.; Bouten, C.V.C.; Smit, T.H.

    2004-01-01

    Centrifuges are often used in biological studies for 1xg control samples in space flight microgravity experiments as well as in ground based research. Using centrifugation as a tool to generate an Earth like acceleration introduces unwanted inertial shear forces to the sample. Depending on the

  14. Design of Structural Parameters for Centrifugal Elevator Overspeed Governors

    Directory of Open Access Journals (Sweden)

    Song Yunpu

    2014-01-01

    Full Text Available As an important part of overspeed and fail-safe protection for elevators, the centrifugal elevator overspeed governor is a device for limiting overspeed of elevator cars. This paper researches on the vibration of the centrifugal block, which plays a key role in the performance of this overspeed governor. By performing dynamics analysis on the centrifugal block, the differential equation on the vibration of the centrifugal block is established. Based on this, the paper performs simulation analysis on the influence of systematic parameters such as the speed of the overspeed governor sheave, the mass of centrifugal block, the turning radius of the centrifugal block, the position where the spring acts, and the stiffness of the centrifugal block spring, on the vibration of the centrifugal block, and finds out their specific influence relationship.

  15. Evaluation of the Hydraulic Performance and Mass Transfer Efficiency of the CSSX Process with the Optimized Solvent in a Single Stage of 5.5-Cm Diameter Centrifugal Contactor

    International Nuclear Information System (INIS)

    Law, J.D.; Tillotson, R.D.; Todd, T.A.

    2002-01-01

    The Caustic-Side Solvent Extraction (CSSX) process has been selected for the separation of cesium from Savannah River Site high-level waste. The solvent composition used in the CSSX process was recently optimized so that the solvent is no longer supersaturated with respect to the calixarene crown ether extractant. Hydraulic performance and mass transfer efficiency testing of a single stage of 5.5-cm ORNL-designed centrifugal contactor has been performed for the CSSX process with the optimized solvent. Maximum throughputs of the 5.5-cm centrifugal contactor, as a function of contactor rotor speed, have been measured for the extraction, scrub, strip, and wash sections of the CSSX flowsheet at the baseline organic/aqueous flow ratios (O/A) of the process, as well as at O/A's 20% higher and 20% lower than the baseline. Maximum throughputs are comparable to the design throughput of the contactor, as well as with throughputs obtained previously in a 5-cm centrifugal contactor with the non-optimized CSSX solvent formulation. The 20% variation in O/A had minimal effect on contactor throughput. Additionally, mass transfer efficiencies have been determined for the extraction and strip sections of the flowsheet. Efficiencies were lower than the process goal of greater than or equal to 80%, ranging from 72 to 75% for the extraction section and from 36 to 60% in the strip section. Increasing the mixing intensity and/or the solution level in the mixing zone of the centrifugal contactor (residence time) could potentially increase efficiencies. Several methods are available to accomplish this including (1) increasing the size of the opening in the bottom of the rotor, resulting in a contactor which is partially pumping instead of fully pumping, (2) decreasing the number of vanes in the contactor, (3) increasing the vane height, or (4) adding vanes on the rotor and baffles on the housing of the contactor. The low efficiency results obtained stress the importance of proper design of

  16. Theoretical considerations in solid bowl centrifugation

    International Nuclear Information System (INIS)

    Hamilton, R.T.

    1979-01-01

    A combination of literature survey and independent analysis determined three relationships for the prediction of the critical (or minimum recoverable) particle size in a solid bowl centrifuge. The relationships were derived based on three different theories of fluid behavior within the centrifuge; (1) laminar film flow (laminar film model), (2) plug flow (Sharples Model), and parabolic flow (modified Sharples Model). The critical particle size for the centrifuge used in Cs-PTA recovery in the CAW process predicted by the three relationships range from 0.19 to 0.34 μm (1 μm = 10 -6 m). The laminar film model gives the most conservative estimate of critical particle size (0.34 μm) and the resulting relationship is recommended for use to predict solid bowl centrifuge performance. Three correction factors are incorporated into the predictive equations to account for the effects of fluid turbulence near the centrifuge feed point, fluid lag and hindered settling. Of these factors, turbulence near the feed point (which is accounted for by using an effective centrifuge length) has the greatest impact, increasing the predicted critical particle size by 15%, while the combination of fluid lag and hindered settling factors increase the recoverable particle size by 4%. The overall effect of the correction factors is an approximately 20% decrease in centrifuge effectivity. The fraction of solids smaller than the critical size range has not been reliably determined for laboratory or plant prepared Cs-PTA. In addition, the density of Cs-PTA crystals is reported to vary from 3.2 to 12 grams per cubic centimeter

  17. Infusion of Trx-1-overexpressing hucMSC prolongs the survival of acutely irradiated NOD/SCID mice by decreasing excessive inflammatory injury.

    Science.gov (United States)

    Hu, JiangWei; Yang, ZaiLiang; Wang, Jun; Tang, YongYong; Liu, Hao; Zhang, Bin; Chen, Hu

    2013-01-01

    A protective reagent for ARI should have the ability to repair injured tissue caused by radiation and prevent continuous damage from secondary risk factors. Trx-1 was explored as a candidate therapy for ARI, as it scavenges reactive oxygen species, regulates cell growth and differentiation, participates in immune reactions, and inhibits apoptosis by acting inside and/or outside cells. Trx-1 can also decrease excessive inflammation in ARI by regulating the creation of inflamed media, by inhibiting the activation of complement, and by reducing the chemotaxis, adhesion, and migration of inflammatory cells. As effectively and stably expressing exogenous genes in the long term and regulating immune inflammation and tissue repair, MSC are a good choice for Trx-1 gene therapy. In this study, Trx-1-overexpressing hucMSC-Trx-1 were obtained by adenoviral vector-mediated infection. We first measured the redox capacity of hucMSC-Trx-1 with an antioxidant capacity (T-AOC) assay, a hydrogen peroxide (H2O2) content determination assay in vivo, a H2O2-induced oxidation hemolysis assay, and a lipid peroxidation assay in vitro. Then, we measured survival time, the protection of the hematopoietic system, and the regulation of inflammation in important organs in three treatment groups of NOD/SCID mice (treated with hucMSC-Trx-1, with hucMSC, and with saline) that were exposed to 4.5 Gy (60)Co-γ-ray radiation. The hucMSC-Trx-1 group achieved superior antioxidation results, protecting bone marrow hematopoietic stem cells (Lin(-)CD117(+): hucMSC-Trx-1 vs. hucMSC, PTrx-1 vs. NS, PTrx-1 vs. hucMSC or NS, PTrx-1 vs. NS, PTrx-1 vs. hucMSC, PTrx-1 vs. NS, PTrx-1 vs. hucMSC, PTrx-1 vs. hucMSC or NS, PTrx-1 combines the merits of gene and cell therapy as a multifunctional radioprotector for ARI.

  18. Water Dynamics and Dewetting Transitions in the Small Mechanosensitive Channel MscS

    Science.gov (United States)

    Anishkin, Andriy; Sukharev, Sergei

    2004-01-01

    The dynamics of confined water in capillaries and nanotubes suggests that gating of ion channels may involve not only changes of the pore geometry, but also transitions between water-filled and empty states in certain locations. The recently solved heptameric structure of the small mechanosensitive channel of Escherichia coli, MscS, has revealed a relatively wide (7–15 Å) yet highly hydrophobic transmembrane pore. Continuum estimations based on the properties of pore surface suggest low conductance and a thermodynamic possibility of dewetting. To test the predictions we performed molecular dynamics simulations of MscS filled with flexible TIP3P water. Irrespective to the initial conditions, several independent 6-ns simulations converged to the same stable state with the pore water-filled in the wider part, but predominantly empty in the narrow hydrophobic part, displaying intermittent vapor-liquid transitions. The polar gain-of-function substitution L109S in the constriction resulted in a stable hydration of the entire pore. Steered passages of Cl− ions through the narrow part of the pore consistently produced partial ion dehydration and required a force of 200–400 pN to overcome an estimated barrier of 10–20 kcal/mole, implying negligibly low conductance. We conclude that the crystal structure of MscS does not represent an open state. We infer that MscS gate, which is similar to that of the nicotinic ACh receptor, involves a vapor-lock mechanism where limited changes of geometry or surface polarity can locally switch the regime between water-filled (conducting) and empty (nonconducting) states. PMID:15111405

  19. Gas dynamics in strong centrifugal fields

    OpenAIRE

    Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

    2017-01-01

    Dynamics of waves generated by scopes in gas centrifuges (GC) for isotope separation is considered. The centrifugal acceleration in the GC reaches values of the order of $10^6$g. The centrifugal and Coriolis forces modify essentially the conventional sound waves. Three families of the waves with different polarisation and dispersion exist in these conditions. Dynamics of the flow in the model GC Iguasu is investigated numerically. Comparison of the results of the numerical modelling of the wa...

  20. Measurement and Analysis of the Noise Radiated by Low Mach Number Centrifugal Blowers.

    Science.gov (United States)

    Yeager, David Marvin

    An investigation was performed of the broad band, aerodynamically generated noise in low tip-speed Mach number, centrifugal air moving devices. An interdisciplinary experimental approach was taken which involved investigation of the aerodynamic and acoustic fields, and their mutual relationship. The noise generation process was studied using two experimental vehicles: (1) a scale model of a homologous family of centrifugal blowers typical of those used to cool computer and business equipment, and (2) a single blade from a centrifugal blower impeller placed in a known, controllable flow field. The radiation characteristics of the model blower were investigated by measuring the acoustic intensity distribution near the blower inlet and comparing it with the intensity near the inlet to an axial flow fan. Results showed that the centrifugal blower is a distributed, random noise source, unlike an axial fan which exhibited the effects of a coherent, interacting source distribution. Aerodynamic studies of the flow field in the inlet and at the discharge to the rotating impeller were used to assess the mean flow distribution through the impeller blade channels and to identify regions of excessive turbulence near the rotating blade row. Both circumferential and spanwise mean flow nonuniformities were identified along with a region of increased turbulence just downstream of the scroll cutoff. The fluid incidence angle, normally taken as an indicator of blower performance, was estimated from mean flow data as deviating considerably from an ideal impeller design. An investigation of the noise radiated from the single, isolated airfoil was performed using modern correlation and spectral analysis techniques. Radiation from the single blade in flow was characterized using newly developed expressions for the correlation area and the dipole source strength per unit area, and from the relationship between the blade surface pressure and the incident turbulent flow field. Results

  1. Liquid centrifugation for nuclear waste partitioning

    International Nuclear Information System (INIS)

    Bowman, C.D.

    1992-01-01

    The performance of liquid centrifugation for nuclear waste partitioning is examined for the Accelerator Transmutation of Waste Program currently under study at the Los Alamos National Laboratory. Centrifugation might have application for the separation of the LiF-BeF 2 salt from heavier radioactive materials fission product and actinides in the separation of fission product from actinides, in the isotope separation of fission-product cesium before transmutation of the 137 Cs and 135 Cs, and in the removal of spallation product from the liquid lead target. It is found that useful chemical separations should be possible using existing materials for the centrifuge construction for all four cases with the actinide fraction in fission product perhaps as low as 1 part in 10 7 and the fraction of 137 CS in 133 Cs being as low as a few parts in 10 5 . A centrifuge cascade has the advantage that it can be assembled and operated as a completely closed system without a waste stream except that associated with maintenance or replacement of centrifuge components

  2. Radial loads and axial thrusts on centrifugal pumps

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The proceedings of a seminar organised by the Power Industries Division of the IMechE are presented in this text. Complete contents: Review of parameters influencing hydraulic forces on centrifugal impellers; The effect of fluid forces at various operation conditions on the vibrations of vertical turbine pumps; A review of the pump rotor axial equilibrium problem - some case studies; Dynamic hydraulic loading on a centrifugal pump impeller; Experimental research on axial thrust loads of double suction centrifugal pumps; A comparison of pressure distribution and radial loads on centrifugal pumps; A theoretical and experimental investigation of axial thrusts within a multi-stage centrifugal pump

  3. Cytokine treatment optimises the immunotherapeutic effects of umbilical cord-derived MSC for treatment of inflammatory liver disease

    NARCIS (Netherlands)

    S.F. De Witte (Samantha Fh); A. Merino (Ana); M. Franquesa (Marcella); T. Strini (Tanja); J.A.A. van Zoggel (Hanneke); S.S. Korevaar (Sander); F. Luk (Franka); M. Gargesha (Madhusudhana); O'Flynn, L. (Lisa); D. Roy (Debashish); Elliman, S.J. (Steve J.); Newsome, P.N. (Philip N.); C.C. Baan (Carla); M.J. Hoogduijn (Martin)

    2017-01-01

    textabstractBackground: Mesenchymal stromal cells (MSC) possess immunomodulatory properties and low immunogenicity, both crucial properties for their development into an effective cellular immunotherapy. They have shown benefit in clinical trials targeting liver diseases; however the efficacy of MSC

  4. Mathematical and physical modeling of rainfall in centrifuge

    OpenAIRE

    CAICEDO, Bernardo; THOREL, Luc; TRISTANCHO, Julian

    2015-01-01

    Rainfall simulation in centrifuge models is important for modelling soil-atmosphere interactions. However, the presence of Coriolis force, drag forces, evaporation and wind within the centrifuge may affect the distribution of rainfall over the model. As a result, development of appropriate centrifuge rain simulators requires a demanding process of experimental trial and error. This paper highlights the key factors involved in controlling rainfall in centrifuge simulations, develops a mathemat...

  5. Assessment of parameters of gas centrifuge and separation cascade basing on integral characteristics of separation plant

    Energy Technology Data Exchange (ETDEWEB)

    Borisevich, Valentin, E-mail: VDBorisevich@mephi.ru [National Research Nuclear University MEPhI, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); National Research Center “Kurchatov Institute”, Kurchatov Square 1, Moscow 123182 (Russian Federation); Borshchevskiy, Michael, E-mail: Michael_mephi@mail.ru [National Research Nuclear University MEPhI, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Andronov, Igor, E-mail: andronov@imp.kiae.ru [National Research Center “Kurchatov Institute”, Kurchatov Square 1, Moscow 123182 (Russian Federation); Senchenkov, Sergey, E-mail: senchenkov@imp.kiae.ru [National Research Center “Kurchatov Institute”, Kurchatov Square 1, Moscow 123182 (Russian Federation)

    2013-12-15

    Highlights: • We developed the calculation method to assess a feed flow rate into a gas centrifuge. • It is based on the knowledge of the integral characteristics of a separation plant. • Our method is verified by comparison with the results of the independent one. • The method also allows to specify other features of the separation cascade work. - Abstract: A calculation technique to assess a feed flow rate into a single GC, a total number of centrifuges in a separation cascade and to determine its likely configurations basing on the known integral characteristics of a centrifugal plant is developed. Evaluation of characteristics of the industrial gas centrifuge TC-12 and separation cascades of the NEF plant performed by two independent calculation techniques demonstrates their satisfactory agreement. This methodology would help to some extent the nuclear inspectors in evaluating and assessing the capability of an enrichment facility, and discovering any use for undeclared purposes.

  6. Centrifuge advances using HTS magnetic bearings

    Science.gov (United States)

    Werfel, F. N.; Flögel-Delor, U.; Rothfeld, R.; Wippich, D.; Riedel, T.

    2001-05-01

    Passive magnetic bearings are of increasing technical interest. We performed experiments with centrifugal rotors to analyze gyroscopic forces in terms imbalance, rotor elasticity and damping. Centrifuge rotors need to be operated soft and stable without whirling the sediments. In order to evaluate optimal parameters critical and resonance behaviors are investigated. Eccentricities up 2 mm are safely passed by accelerating test wheels. In a simple model we describe the effect of passing critical rotational speeds. Measurements of bearing properties and wheel performance are presented. We have constructed a first prototype centrifuge designed with a HTS double bearing which operates a titanium rotor safely up to 30 000 rpm. A 15 W Stirling cooler serves cryogenics of the YBCO stators. From the experiments design guidelines for centrifugal applications with HTS bearings are given.

  7. Kinetically limited differential centrifugation as an inexpensive and readily available alternative to centrifugal elutriation.

    Science.gov (United States)

    Tan, Jinwang; Lee, Byung-Doo; Polo-Parada, Luis; Sengupta, Shramik

    2012-08-01

    When separating two species with similar densities but differing sedimentation velocities (because of differences in size), centrifugal elutriation is generally the method of choice. However, a major drawback to this approach is the requirement for specialized equipment. Here, we present a new method that achieves similar separations using standard benchtop centrifuges by loading the seperands as a layer on top of a dense buffer of a specified length, and running the benchtop centrifugation process for a calculated amount of time, thereby ensuring that all faster moving species are collected at the bottom, while all slower moving species remain in the buffer. We demonstrate the use of our procedure to isolate bacteria from blood culture broth (a mixture of bacterial growth media, blood, and bacteria).

  8. Centrifuge workers study. Phase II, completion report

    International Nuclear Information System (INIS)

    Wooten, H.D.

    1994-09-01

    Phase II of the Centrifuge Workers Study was a follow-up to the Phase I efforts. The Phase I results had indicated a higher risk than expected among centrifuge workers for developing bladder cancer when compared with the risk in the general population for developing this same type of cancer. However, no specific agent could be identified as the causative agent for these bladder cancers. As the Phase II Report states, Phase I had been limited to workers who had the greatest potential for exposure to substances used in the centrifuge process. Phase II was designed to expand the survey to evaluate the health of all employees who had ever worked in Centrifuge Program Departments 1330-1339 but who had not been interviewed in Phase I. Employees in analytical laboratories and maintenance departments who provided support services for the Centrifuge Program were also included in Phase II. In December 1989, the Oak Ridge Associated Universities (ORAU), now known as Oak Ridge Institute for Science and Education (ORISE), was contracted to conduct a follow-up study (Phase II). Phase H of the Centrifuge Workers Study expanded the survey to include all former centrifuge workers who were not included in Phase I. ORISE was chosen because they had performed the Phase I tasks and summarized the corresponding survey data therefrom

  9. Centrifuge workers study. Phase II, completion report

    Energy Technology Data Exchange (ETDEWEB)

    Wooten, H.D.

    1994-09-01

    Phase II of the Centrifuge Workers Study was a follow-up to the Phase I efforts. The Phase I results had indicated a higher risk than expected among centrifuge workers for developing bladder cancer when compared with the risk in the general population for developing this same type of cancer. However, no specific agent could be identified as the causative agent for these bladder cancers. As the Phase II Report states, Phase I had been limited to workers who had the greatest potential for exposure to substances used in the centrifuge process. Phase II was designed to expand the survey to evaluate the health of all employees who had ever worked in Centrifuge Program Departments 1330-1339 but who had not been interviewed in Phase I. Employees in analytical laboratories and maintenance departments who provided support services for the Centrifuge Program were also included in Phase II. In December 1989, the Oak Ridge Associated Universities (ORAU), now known as Oak Ridge Institute for Science and Education (ORISE), was contracted to conduct a follow-up study (Phase II). Phase H of the Centrifuge Workers Study expanded the survey to include all former centrifuge workers who were not included in Phase I. ORISE was chosen because they had performed the Phase I tasks and summarized the corresponding survey data therefrom.

  10. Sertifikaatit ravintolassa : Luomu, UTZ, MSC, ASC

    OpenAIRE

    Hakamäki, Henna

    2017-01-01

    Tämän opinnäytetyön tarkoituksena on selvittää tietävätkö ihmiset, mitä sertifikaatit tarkoittavat, olisivatko asiakkaat valmiita maksamaan sertifioiduista raaka-aineista tehdystä ruoasta enemmän ja markkinoivatko ravintolat käytössä olevia sertifikaatteja riittävästi saadakseen siitä hyödyn. Tulosten perusteella pyrittiin selvittämään kannattaako yritysten panostaa sertifikaattien markkinointiin. Teoriaosassa käsitellään neljää opinnäytetyöhön valikoitua sertifikaattia: luomu, UTZ, MSC ...

  11. Comparing and contrasting Escherichia coli and Mycobacterium tuberculosis mechanosensitive channels (MscL) - New gain of function mutations in the loop region

    OpenAIRE

    Maurer, Joshua A.; Elmore, Donald E.; Lester, Henry A.; Dougherty, Dennis A.

    2000-01-01

    Sequence analysis of 35 putative MscL homologues was used to develop an optimal alignment for Escherichia coli and Mycobacterium tuberculosis MscL and to place these homologues into sequence subfamilies. By using this alignment, previously identified E. coli MscL mutants that displayed severe and very severe gain of function phenotypes were mapped onto the M. tuberculosis MscL sequence. Not all of the resulting M. tuberculosis mutants displayed a gain of function phenotype; for instance, norm...

  12. Coordinates for a High Performance 4:1 Pressure Ratio Centrifugal Compressor

    Science.gov (United States)

    McKain, Ted F.; Holbrook, Greg J.

    1997-01-01

    The objective of this program was to define the aerodynamic design and manufacturing coordinates for an advanced 4:1 pressure ratio, single stage centrifugal compressor at a 10 lbm/sec flow size. The approach taken was to perform an exact scale of an existing DDA compressor originally designed at a flow size of 3.655 lbm/sec.

  13. Development of a 3D circular microfluidic centrifuge for the separation of mixed particles by using their different centrifuge times

    International Nuclear Information System (INIS)

    Jeon, H J; Kim, D I; Kim, M J; Nguyen, X D; Park, D H; Go, J S

    2015-01-01

    This paper presents a circular microfluidic centrifuge with two inlets and two outlets to separate mixed microparticles with a specially designed sample injection hole. To separate the mixed particles, it uses a rotational flow, generated in a chamber by counter primary flows in the microchannels. The shape and sizes of the circular microfluidic centrifuge have been designed through numerical evaluation to have a large relative centrifugal force. The difference of centrifuge times of the mixed particles of 1 μm and 6 μm was determined to be 8.2 s at an inlet Reynolds number of 500 and a sample Reynolds number of 20. In the experiment, this was measured to be about 10 s. From the separation of the two polymer particles analogous to the representative sizes of platelets and red blood cells, the circular microfluidic centrifuge shows a potential to separate human blood cells size-selectively by using the difference of centrifuge times. (paper)

  14. Waves in Strong Centrifugal Field

    Science.gov (United States)

    Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

    Dynamics of waves generated by scopes in gas centrifuges (GC) for isotope separation is considered. The centrifugal acceleration in the GC reaches values of the order of 106g. The centrifugal and Coriolis forces modify essentially the conventional sound waves. Three families of the waves with different polarization and dispersion exist in these conditions. Dynamics of the flow in the model GC Iguasu is investigated numerically. Comparison of the results of the numerical modeling of the wave dynamics with the analytical predictions is performed. New phenomena of the resonances in the GC is found. The resonances occur for the waves polarized along the rotational axis having the smallest dumping due to the viscosity.

  15. Centrifugal force: a few surprises

    International Nuclear Information System (INIS)

    Abramowicz, M.A.; Max-Planck-Institut fuer Physik und Astrophysik, Garching

    1990-01-01

    The need for a rather fundamental revision in understanding of the nature of the centrifugal force is discussed. It is shown that in general relativity (and contrary to the situation in Newtonian theory) rotation of a reference frame is a necessary but not sufficient condition for the centrifugal force to appear. A sufficient condition for its appearance, in the instantaneously corotating reference frame of a particle, is that the particle motion in space (observed in the global rest frame) differs from a photon trajectory. The direction of the force is the same as that of the gradient of the effective potential for photon motion. In some cases, the centrifugal force will attract towards the axis of rotation. (author)

  16. Further Developments on Optimum Structural Design Using MSC/Nastran and Sequential Quadratic Programming

    DEFF Research Database (Denmark)

    Holzleitner, Ludwig

    1996-01-01

    , here the shape of two dimensional parts with different thickness areas will be optimized. As in the previos paper, a methodology for structural optimization using the commercial finite element package MSC/NASTRAN for structural analysis is described. Three different methods for design sensitivity......This work is closely connected to the paper: K.G. MAHMOUD, H.W. ENGL and HOLZLEITNER: "OPTIMUM STRUCTURAL DESIGN USING MSC/NASTRAN AND SEQUENTIAL QUADRATIC PROGRAMMING", Computers & Structures, Vol. 52, No. 3, pp. 437-447, (1994). In contrast to that paper, where thickness optimization is described...

  17. Therapeutic use of human mesenchymal stem cells (MSC) for the treatment of radio-induced diseases

    International Nuclear Information System (INIS)

    Mouiseddine, Moubarak

    2008-05-01

    Ionising radiation can induce toxic effects on body. They provoke physiological modifications of tissues and organs which can be lethal. Total body irradiation or local abdominal irradiation can induce serious complications. Intestine is the first tissue concerned by these side effects. Radiation induces malabsorption of the intestine and lost of it integrity. Radio-induced physiopathological effects on intestine could lead to distant effects on other tissues and organs such as liver. The actual treatments have a limited efficiency or are not adapted to gastrointestinal damages. Indeed, in this type of lesions, the heterogeneous systems which are concerned and the gravity of lesions complicates the medical care. Our purpose is to show that cell therapy using human mesenchymal stem cells (MSC) constitutes resolution in this type of illness. The works which are presented in this thesis show that MSC are multi-potent and have heterogeneous expression of molecules. These cells are able to establish themselves in many organs and tissues after injection into irradiated body. Thus we have shown that MSC can prevent the small intestine from radio-induced damages. Indeed we demonstrate that through their actions on gut, MSC can indirectly restore hepatic integrity. (author)

  18. NASA low speed centrifugal compressor

    Science.gov (United States)

    Hathaway, Michael D.

    1990-01-01

    The flow characteristics of a low speed centrifugal compressor were examined at NASA Lewis Research Center to improve understanding of the flow in centrifugal compressors, to provide models of various flow phenomena, and to acquire benchmark data for three dimensional viscous flow code validation. The paper describes the objectives, test facilities' instrumentation, and experiment preliminary comparisons.

  19. Hydraulic performance of a multistage array of advanced centrifugal contactors

    International Nuclear Information System (INIS)

    Hodges, M.E.

    1984-01-01

    The hydraulic characteristics of an advanced design centrifugal contactor array have been determined at the Savannah River Laboratory (SRL). The advanced design utilizes couette mixing (Taylor vortices) in the annulus between the rotating and stationary bowls. Excellent phase separation over a wide range of flow conditions was obtained. Interfaces within an entire eight-stage array were controlled with a single weir air pressure. 2 references, 5 figures

  20. Separation of uranium isotopes by gas centrifugation

    International Nuclear Information System (INIS)

    Jordan, I.

    1980-05-01

    The uranium isotope enrichment is studied by means of the countercurrent gas centrifuge driven by thermal convection. A description is given of (a) the transfer and purification of the uranium hexafluoride used as process gas in the present investigation; (b) the countercurrent centrifuge ZG3; (c) the system designed for the introduction and extraction of the process gas from the centrifuge; (d) the measurement of the process gas flow rate through the centrifuge; (e) the determination of the uranium isotopic abundance by mass spectrometry; (f) the operation and mechanical behavior of the centrifuge and (g) the isotope separation experiments, performed, respectively, at total reflux and with production of enriched material. The results from the separation experiments at total reflux are discussed in terms of the enrichment factor variation with the magnitude and flow profile of the countercurrent given by the temperature difference between the rotor covers. As far as the separation experiments with production are concerned, the discussion of their results is presented through the variation of the enrichment factor as a function of the flow rate, the observed asymmetry of the process and the calculated separative power of the centrifuge. (Author) [pt

  1. Unexpected properties of the centrifugal force

    International Nuclear Information System (INIS)

    Abramowicz, M.A.

    1990-01-01

    Contrary to what is stated in the Newtonian dynamics, rotation of a reference frame is not sufficient for the occurrence of the centrifugal force. Instead, the necessary and sufficient condition is a motion along a path different from that of a photon trajectory in space. This calls for a rather fundamental change in understanding of the very nature of the centrifugal force. It also has important practical physical consequences: in a strong gravitational field, where light trajectories are substantially curved, centrifugal force is much weaker than the Newtonian theory predicts. In addition, when there are closed (circular) photon trajectories in space, the centrifugal force may reverse its direction - it attracts towards the rotation axis!. The weakening of the centrifugal force in strong gravitational fields and the reversal of its direction in the neighbourhood of close photon trajectories in space fully and clearly explain puzzling examples of counter intuitive behaviour of dynamical effects of rotation found previously by several authors: e.g. reversal of the ellipticity behaviour of the relativistic Maclaurin spheroids (Chandrasekhar and Miller, 1974), reversal of the viscous torque action (Anderson and Lemos, 1988), or the fact that rotation increases internal pressure of a sufficiently compact star (Abramowicz and Wagoner, 1974). Weakening of the centrifugal force implies that rotating neutron stars are less oblate (and probably more stable) than the Newtonian theory predicts. This is important for the recently discussed question of how fast can pulsars spin. (author). 23 refs, 3 figs

  2. Unexpected properties of the centrifugal force

    International Nuclear Information System (INIS)

    Abramowicz, M.A.

    1990-01-01

    Contrary to what is stated in the Newtonian dynamics, rotation of a reference frame is not sufficient for the occurrence of the centrifugal force. Instead, the necessary and sufficient condition is a motion along a path different from that of a photon trajectory in space. This calls for a rather fundamental change in understanding of the very nature of the centrifugal force. It also has important practical physical consequences: in a strong gravitational field, where light trajectories are substantially curved, centrifugal force is much weaker than the Newtonian theory predicts. In addition, when there are closed (circular) photon trajectories in space, the centrifugal force may reverse its direction - it attracts towards the rotation axis. The weakening of the centrifugal force in strong gravitational fields and the reversal of its direction in the neighborhood of close photon trajectories in space fully and clearly explain puzzling examples of counter intuitive behaviour of dynamical effects of rotation found previously by several authors: e.g. reversal of the ellipticity behaviour of the relativistic Maclaurin spheroids (Chandrasekhar and Miller, 1974), reversal of the viscous torque action (Anderson and Lemos, 1988) or the fact that rotation increases internal pressure of a sufficiently compact star (Abramowicz and Wagoner, 1974). Weakening of the centrifugal force implies that rotating neutron stars are less oblate (and probably more stable) than the Newtonian theory predicts. This is important for the recently discussed question of how fast can pulsars spins. (author). 31 refs, 3 figs

  3. Bacterial Cell Surface Damage Due to Centrifugal Compaction

    NARCIS (Netherlands)

    Peterson, Brandon W.; Sharma, Prashant K.; van der Mei, Henny C.; Busscher, Henk J.

    Centrifugal damage has been known to alter bacterial cell surface properties and interior structures, including DNA. Very few studies exist on bacterial damage caused by centrifugation because of the difficulty in relating centrifugation speed and container geometry to the damage caused. Here, we

  4. Centrifuge Facility for the International Space Station Alpha

    Science.gov (United States)

    Johnson, Catherine C.; Hargens, Alan R.

    1994-01-01

    The Centrifuge Facility planned for the International Space Station Alpha has under-one considerable redesign over the past year, primarily because the Station is now viewed as a 10 year mission rather than a 30 year mission and because of the need to simply the design to meet budget constraints and a 2000 launch date. The basic elements of the Centrifuge Facility remain the same, i.e., a 2.5 m diameter centrifuge, a micro-g holding unit, plant and animal habitats, a glovebox and a service unit. The centrifuge will still provide the full range of artificial gravity from 0.01 a to 2 - as originally planned; however, the extractor to permit withdrawal of habitats from the centrifuge without stopping the centrifuge has been eliminated. The specimen habitats have also been simplified and are derived from other NASA programs. The Plant Research Unit being developed by the Gravitational Biology Facility will be used to house plants in the Centrifuge Facility. Although not as ambitious as the Centrifuge Facility plant habitat, it will provide much better environmental control and lighting than the current Shuttle based Plant Growth Facility. Similarly, rodents will be housed in the Advanced Animal Habitat being developed for the Shuttle program. The Centrifuge Facility and ISSA will provide the opportunity to perform repeatable, high quality science. The long duration increments available on the Station will permit multigeneration studies on both plants and animals which have not previously been possible. The Centrifuge Facility will accommodate sufficient number of specimens to permit statistically significant sampling of specimens to investigate the time course of adaptation to altered gravity environments. The centrifuge will for the first time permit investigators to use gravity itself as a tool to investigate fundamental processes, to investigate the intensity and duration of gravity to maintain normal structure and function, to separate the effects of micro-g from

  5. MiR-9-5p promotes MSC migration by activating β-catenin signaling pathway.

    Science.gov (United States)

    Li, Xianyang; He, Lihong; Yue, Qing; Lu, Junhou; Kang, Naixin; Xu, Xiaojing; Wang, Huihui; Zhang, Huanxiang

    2017-07-01

    Mesenchymal stem cells (MSCs) have the potential to treat various tissue damages, but the very limited number of cells that migrate to the damaged region strongly restricts their therapeutic applications. Full understanding of mechanisms regulating MSC migration will help to improve their migration ability and therapeutic effects. Increasing evidence shows that microRNAs play important roles in the regulation of MSC migration. In the present study, we reported that miR-9-5p was upregulated in hepatocyte growth factor -treated MSCs and in MSCs with high migration ability. Overexpression of miR-9-5p promoted MSC migration, whereas inhibition of endogenous miR-9-5p decreased MSC migration. To elucidate the underlying mechanism, we screened the target genes of miR-9-5p and report for the first time that CK1α and GSK3β, two inhibitors of β-catenin signaling pathway, were direct targets of miR-9-5p in MSCs and that overexpression of miR-9-5p upregulated β-catenin signaling pathway. In line with these data, inhibition of β-catenin signaling pathway by FH535 decreased the miR-9-5p-promoted migration of MSCs, while activation of β-catenin signaling pathway by LiCl rescued the impaired migration of MSCs triggered by miR-9-5p inhibitor. Furthermore, the formation and distribution of focal adhesions as well as the reorganization of F-actin were affected by the expression of miR-9-5p. Collectively, these results demonstrate that miR-9-5p promotes MSC migration by upregulating β-catenin signaling pathway, shedding light on the optimization of MSCs for cell replacement therapy through manipulating the expression level of miR-9-5p. Copyright © 2017 the American Physiological Society.

  6. Numerical simulation of flow in centrifugal pump under cavitation and sediment condition

    International Nuclear Information System (INIS)

    Lu, J L; Guo, P C; Zheng, X B; Zhao, Q; Luo, X Q

    2012-01-01

    The sediment concentration is very high in many rivers in the world, especially in China. The pumps that designed for the clear water are usually seriously abraded. The probability of pump cavitation is greatly enhanced due to the existence of sand. Under the joint action and mutual promotion of sand erosion and cavitation, serious abrasion could occurred, and the hydraulic performance of the pump may be greatly descended, meanwhile the safety and stability of the whole pump are greatly threatened. Therefore, it is significant to investigate the cavitation characteristic of pump under sediment flow condition. In this paper, the flow in a single stage centrifugal pump under cleat water and sediment flow conditions was numerically simulated. The cavitation performance under clear water was firstly analyzed. Then, The pressure, velocity and solid particle distribution in centrifugal pump under different particle diameter and different particle concentration was investigated by using the two-fluid model; The area and extent of erosion was illustrated by using the particle track model. Finally, the influence of mixed sand on centrifugal pump performance was investigated.

  7. Enhanced infectivity of bluetongue virus in cell culture by centrifugation.

    OpenAIRE

    Sundin, D R; Mecham, J O

    1989-01-01

    The effects of centrifugation of the infection of cell culture with bluetongue virus (BTV) were investigated. Baby hamster kidney cells were infected with BTV with or without centrifugation. Viral antigen was detected by immunofluorescence at 24 h in both centrifuged and noncentrifuged cultures. However, after 24 h of infection, the production of PFU in centrifuged cell cultures was 10- to 20-fold greater than that seen in cultures not centrifuged. In addition, centrifugation enhanced the dir...

  8. Measurement and analysis of the noise radiated by low Mach numbers centrifugal blowers

    Science.gov (United States)

    Yeager, D. M.; Lauchle, G. C.

    1987-11-01

    The broad band, aerodynamically generated noise in low tip-speed Mach number, centrifugal air moving devices is investigated. An interdisciplinary approach was taken which involved investigation of the aerodynamic and acoustic fields, and their mutual relationship. The noise generation process was studied using two experimental vehicles: (1) a scale model of a homologous family of centrifugal blowers typical of those used to cool computer and business equipment, and (2) a single blade from a centrifugal blower impeller which was placed in a known, controllable flow field. The radiation characteristics of the model blower were investigated by measuring the acoustic intensity distribution near the blower inlet and comparing it with the intensity near the inlet to an axial flow fan. Aerodynamic studies of the flow field in the inlet and at the discharge to the rotating impeller were used to assess the mean flow distribution through the impeller blade channels and to identify regions of excessive turbulence near the rotating blade row. New frequency-domain expressions for the correlation area and dipole source strength per unit area on a surface immersed in turbulence were developed which can be used to characterize the noise generation process over a rigid surface immersed in turbulence. An investigation of the noise radiated from the single, isolated airfoil (impeller blade) was performed using modern correlation and spectral analysis techniques.

  9. Adaptive MscS gating in the osmotic permeability response in E. coli: the question of time.

    Science.gov (United States)

    Boer, Miriam; Anishkin, Andriy; Sukharev, Sergei

    2011-05-17

    Microorganisms adapt to osmotic downshifts by releasing small osmolytes through mechanosensitive (MS) channels. We want to understand how the small mechanosensitive channel's (MscS) activation and inactivation, both driven by membrane tension, optimize survival in varying hypoosmotic shock situations. By measuring light scattering with a stopped-flow device, we estimate bacterial swelling time as 30-50 ms. A partial solute equilibration follows within 150-200 ms, during which optical responses from cells with WT MscS deviate from those lacking MS channels. MscS opening rates estimated in patch clamp show the channels readily respond to tensions below the lytic limit with a time course faster than 20 ms and close promptly upon tension release. To address the role of the tension-insensitive inactivated state in vivo, we applied short, long, and two-step osmotic shock protocols to WT, noninactivating G113A, and fast-inactivating D62N mutants. WT and G113A showed a comparable survival in short 1 min 800 mOsm downshock experiments, but G113A was at a disadvantage under a long 60 min shock. Preshocking cells carrying WT MscS for 15 s to 15 min with a 200 mOsm downshift did not sensitize them to the final 500 mOsm drop in osmolarity of the second step. However, these two-step shocks induced death in D62N more than just a one-step 700 mOsm downshift. We conclude MscS is able to activate and exude osmolytes faster than lytic pressure builds inside the cell under abrupt shock. During prolonged shocks, gradual inactivation prevents continuous channel activity and assists recovery. Slow kinetics of inactivation in WT MscS ensures that mild shocks do not inactivate the entire population, leaving some protection should conditions worsen.

  10. Applying of centrifugal chromatography on DEAE cellulose and viscosity measurement to estimate damage caused by gamma irradiation in lymphocyte DNA

    International Nuclear Information System (INIS)

    Olinski, R.

    1977-01-01

    DNA isolated from limphocytes of pig blood was irradiated by γ radiation in the range of 0.5-50 Krads. Changes caused by irradiation (single and double breaks) were determined by using viscosity measurement and centrifugal chromatography on DEAE cellulose. Study of DNA chromatograms showed possibility to apply centrifugal chromatography on DEAE cellulose to estimate changes caused by irradiation. (author)

  11. Direct numerical simulation of vacillation in convection induced by centrifugal buoyancy

    Science.gov (United States)

    Pitz, Diogo B.; Marxen, Olaf; Chew, John W.

    2017-11-01

    Flows induced by centrifugal buoyancy occur in industrial systems, such as in the compressor cavities of gas turbines, as well as in flows of geophysical interest. In this numerical study we use direct numerical simulation (DNS) to investigate the transition between the steady waves regime, which is characterized by great regularity, to the vacillation regime, which is critical to understand transition to the fully turbulent regime. From previous work it is known that the onset of convection occurs in the form of pairs of nearly-circular rolls which span the entire axial length of the cavity, with small deviations near the parallel, no-slip end walls. When non-linearity sets in triadic interactions occur and, depending on the value of the centrifugal Rayleigh number, the flow is dominated by either a single mode and its harmonics or by broadband effects if turbulence develops. In this study we increase the centrifugal Rayleigh number progressively and investigate mode interactions during the vacillation regime which eventually lead to chaotic motion. Diogo B. Pitz acknowledges the financial support from the Capes foundation through the Science without Borders program.

  12. Performance prediction of industrial centrifuges using scale-down models.

    Science.gov (United States)

    Boychyn, M; Yim, S S S; Bulmer, M; More, J; Bracewell, D G; Hoare, M

    2004-12-01

    Computational fluid dynamics was used to model the high flow forces found in the feed zone of a multichamber-bowl centrifuge and reproduce these in a small, high-speed rotating disc device. Linking the device to scale-down centrifugation, permitted good estimation of the performance of various continuous-flow centrifuges (disc stack, multichamber bowl, CARR Powerfuge) for shear-sensitive protein precipitates. Critically, the ultra scale-down centrifugation process proved to be a much more accurate predictor of production multichamber-bowl performance than was the pilot centrifuge.

  13. Centrifugation-free washing: A novel approach for removing immunoglobulin A from stored red blood cells.

    Science.gov (United States)

    Vörös, Eszter; Piety, Nathaniel Z; Strachan, Briony C; Lu, Madeleine; Shevkoplyas, Sergey S

    2018-08-01

    Washed red blood cells (RBCs) are indicated for immunoglobulin A (IgA) deficient recipients. Centrifugation-based cell processors commonly used by hospital blood banks cannot consistently reduce IgA below the recommended levels, hence double washing is frequently required. Here, we describe a prototype of a simple, portable, disposable system capable of washing stored RBCs without centrifugation, while reducing IgA below 0.05 mg/dL in a single run. Samples from RBC units (n = 8, leukoreduced, 4-6 weeks storage duration) were diluted with normal saline to a hematocrit of 10%, and then washed using either the prototype washing system, or via conventional centrifugation. The efficiency of the two washing methods was quantified and compared by measuring several key in vitro quality metrics. The prototype of the washing system was able to process stored RBCs at a rate of 300 mL/hour, producing a suspension of washed RBCs with 43 ± 3% hematocrit and 86 ± 7% cell recovery. Overall, the two washing methods performed similarly for most measured parameters, lowering the concentration of free hemoglobin by >4-fold and total free protein by >10-fold. Importantly, the new washing system reduced the IgA level to 0.02 ± 0.01 mg/mL, a concentration 5-fold lower than that produced by conventional centrifugation. This proof-of-concept study showed that centrifugation may be unnecessary for washing stored RBCs. A simple, disposable, centrifugation-free washing system could be particularly useful in smaller medical facilities and resource limited settings that may lack access to centrifugation-based cell processors. © 2017 Wiley Periodicals, Inc.

  14. Headlines... Areva on the way toward centrifugation

    International Nuclear Information System (INIS)

    Anon.

    2004-01-01

    The French industrial group Areva, that gathers Cogema and Framatome-ANP, has entered into a partnership with the British nuclear consortium Urenco for creating ETC (enrichment technology company) in order to replace its uranium enrichment facility (Georges-Besse-I) that is planned to close in 2012 by a new one (George-Besse-II) that will enter into service as early as 2007. The new facility will be based on the centrifugation technique developed by Urenco, this technique will cut the consumption of electricity by 3 in comparison with the gaseous diffusion technique used in the Georges-Besse-I facility. The other asset of the centrifugation technique is that the facility can grow with the number of centrifuges that are set. In 2007 only 7% of the total number of centrifuges will be installed, which will sufficient to satisfy the demand for enriched uranium. The full size of the facility will be reached in 2016 through gradual steps of 10% more centrifuges set every year. (A.C.)

  15. Instabilities expected to exist in a gas centrifuge

    International Nuclear Information System (INIS)

    Sakurai, Takeo

    1977-01-01

    A typical counter current type centrifuge of long bowl geometry is schematically shown. At first glance, the main flow field in this centrifuge can be taken as a swirling pipe flow. Taking in mind the operating gas (uranium hexafluoride) the temperature of which is 20 deg C and the peripheral pressure 10 torrs, the density and pressure obey the barometric relation in which the gravity is replaced by the centrifugal acceleration; in a thermally driven centrifuge, an additional weak temperature gradient appears along the axial direction. These situations are similar to those in the earth's atmosphere. So, it is stressed that the interior of a gas centrifuge is a new kind of rotating atmosphere and offers a 'new face' in the field of geophysical fluid dynamics. Instabilities in inviscid case and the destabilizing effects of the diffusivity are thus discussed together with the effects of the mechanical vibrations of the centrifuge, and vortex breakdown phenomena

  16. Simulation of ultra-long term behavior in HLW near-field by centrifugal model test. Part 1. Development of centrifugal equipment and centrifuge model test method

    International Nuclear Information System (INIS)

    Nishimoto, Soshi; Okada, Tetsuji; Sawada, Masataka

    2011-01-01

    The objective of this paper is to develop a centrifugal equipment which can continuously be run for a long time and a model test method in order to evaluate a long term behavior which is a coupled thermo-hydro-mechanical processes in the high level wastes geological disposal repository and the neighborhood (called 'near-field'). The centrifugal equipment of CRIEPI, 'CENTURY5000-THM', developed in the present study is able to run continuously up to six months. Therefore, a long term behavior in the near-field can be simulated in a short term, for instance, the behavior for 5000 equivalent years can be simulated in six months by centrifugalizing 100 G using a 1/100 size model. We carried out a test using a nylon specimen in a centrifugal force field of 30 G and confirmed the operations of CENTURY5000-THM, control and measurement for 11 days. As the results, it was able to control the stress in the pressure vessel and measure the values of strain, temperature and pressure. And, as a result of scanning the small model of near-field including the metal overpack, bentonite buffer and rock by a medical X-rays CT scanner, the internal structure of the model was able to be evaluated when the metal artifact was reduced. From these results, the evaluation for a long term behavior of a disposal repository by the method of centrifugal model test became possible. (author)

  17. Two-Stage Centrifugal Fan

    Science.gov (United States)

    Converse, David

    2011-01-01

    Fan designs are often constrained by envelope, rotational speed, weight, and power. Aerodynamic performance and motor electrical performance are heavily influenced by rotational speed. The fan used in this work is at a practical limit for rotational speed due to motor performance characteristics, and there is no more space available in the packaging for a larger fan. The pressure rise requirements keep growing. The way to ordinarily accommodate a higher DP is to spin faster or grow the fan rotor diameter. The invention is to put two radially oriented stages on a single disk. Flow enters the first stage from the center; energy is imparted to the flow in the first stage blades, the flow is redirected some amount opposite to the direction of rotation in the fixed stators, and more energy is imparted to the flow in the second- stage blades. Without increasing either rotational speed or disk diameter, it is believed that as much as 50 percent more DP can be achieved with this design than with an ordinary, single-stage centrifugal design. This invention is useful primarily for fans having relatively low flow rates with relatively high pressure rise requirements.

  18. The gas centrifuge, uranium enrichment and nuclear proliferation

    International Nuclear Information System (INIS)

    Chapman, A.

    1988-01-01

    The author considers the consequences for controlling nuclear proliferation of the emergence of the gas centrifuge method for enriching uranium and succeeds in the difficult and delicate task of saying enough about gas centrifuge techniques for readers to judge, what may be involved in fully embracing gas centrifuge enrichment within the constraints of an anti-proliferation strategy, whilst at the same time saying nothing that could be construed as encouraging an interest in the gas centrifuge route to highly enriched uranium where none had before existed. (author)

  19. Results of scatterometer systems analysis for NASA/MSC Earth Observation Sensor Evaluation Program.

    Science.gov (United States)

    Krishen, K.; Vlahos, N.; Brandt, O.; Graybeal, G.

    1971-01-01

    Radar scatterometers have applications in the NASA/MSC Earth Observation Aircraft Program. Over a period of several years, several missions have been flown over both land and ocean. In this paper a system evaluation of the NASA/MSC 13.3-GHz Scatterometer System is presented. The effects of phase error between the Scatterometer channels, antenna pattern deviations, aircraft attitude deviations, environmental changes, and other related factors such as processing errors, system repeatability, and propeller modulation, were established. Furthermore, the reduction in system errors and calibration improvement was investigated by taking into account these parameter deviations. Typical scatterometer data samples are presented.

  20. Separative power of an optimised concurrent gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Bogovalov, Sergey; Boman, Vladimir [National Research Nuclear University (MEPHI), Moscow (Russian Federation)

    2016-06-15

    The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to δU = 12.7 (V/700 m/s)2(300 K/T)(L/1 m) kg·SWU/yr, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

  1. Characteristics of the Aerodynamics and the Noise of a Dual-cascade Centrifugal Fan (Effects of Bare Ratio and Outlet Angle of Scroll Casing)

    OpenAIRE

    畠山, 真; 児玉, 好雄; 佐々木, 壮一; 林, 秀千人; 後藤, 健一

    2002-01-01

    Characteristics of the aerodynamics and the noise of dual-cascade centrifugal fan have been experimentally investigated with respect to the effects of the bare ratio and the outlet angle of scroll casing. It was shown that the performance of the fans became best when the bare ratio was around between 9% to 25%, then the characterisitics of the dualcascade centrifugal fan were superior to that of the single-cascade centrifugal fan. The former was little influenced by the different bare ratio a...

  2. Autobalancing and FDIR for a space-based centrifuge prototype

    Science.gov (United States)

    Wilson, Edward; Mah, Robert W.

    2005-01-01

    This report summarizes centrifuge-related work performed at the Smart Systems Research Laboratory at NASA Ames Research Center's Computational Sciences Division from 1995 through 2003. The goal is to develop an automated system that will sense an imbalance (both static and dynamic3) in a centrifuge and issue control commands to drive counterweights to eliminate the effects of the imbalance. This autobalancing development began when the ISS centrifuge design was not yet finalized, and was designed to work with the SSRL Centrifuge laboratory prototype, constructed in 1993-1995. Significant differences between that prototype and the current International Space Station (ISS) Centrifuge design are that: the spin axis for the SSRL Centrifuge prototype can translate freely in x and y, but not wobble, whereas the ISS centrifuge spin axis has 3 translational and two rotational degrees of freedom, supported by a vibration 34. The imbalance sensors are strained gauges both in the rotor and the stator, measuring the imbalance forces, whereas the ISS centrifuge uses eddy current displacement sensors to measure the displacements resulting from imbalance. High fidelity autobalancing and FDIR systems (for both counterweights and strain gauges) are developed and tested in MATLAB simulation, for the SSRL Centrifuge configuration. Hardware implementation of the autobalancing technology was begun in 1996, but was terminated due to lack of funding. The project lay dormant until 2001-2002 when the FDIR capability was added.

  3. High frequency dynamics in centrifugal compressors

    NARCIS (Netherlands)

    Twerda, A.; Meulendijks, D.; Smeulers, J.P.M.; Handel, R. van den; Lier, L.J. van

    2008-01-01

    Problems with centrifugal compressors relating to high frequency, i.e. Blade passing frequency (BPF) are increasing. Pulsations and vibrations generated in centrifugal compressors can lead to nuisance, due to strong tonal noise, and even breakdown. In several cases the root cause of a failure or a

  4. Thermodynamic simulation of condensation heat recovery characteristics of a single stage centrifugal chiller in a hotel

    International Nuclear Information System (INIS)

    Gong, Guangcai; Chen, Feihu; Su, Huan; Zhou, Jianyong

    2012-01-01

    Highlights: ► Thermodynamic model of a two-condenser condensation system has been carried out. ► Dynamic simulation method has been presented. ► COP and g of the refrigerating system is better than the single condensation system. ► The optimal parameters for the two-condenser condensation system have been studied. -- Abstract: A thermodynamic simulation study has been carried out for a single stage centrifugal chiller in this paper. The cooling capacity of the chiller unit is about 1750 kW. The chiller unit has been set and tested, and the work refrigerant is R22. A heat exchanger has been set between outlet of the compressor and the condenser for sanitary hot water supplying. Then the chiller unit is a kind of combined system that can provide sanitary hot water supplying and air conditioning simultaneously. A thermodynamic simulation model of the combined system has been established with the system simulation toolbox Simulink. Performance of the components and the combined system of the chiller unit has been studied over a wide range of operating conditions. The potential energy and fuel cost saving associated with the use of the proposed combined system for a typical hotel in south China has been estimated. It is showed that the combined system of the chiller unit is very useful in hotel buildings. And the thermodynamic simulation model of the combined system is significance for the optimization of parameters of the chiller unit such as condensation and evaporation temperature, mass flow of the sanitary hot water and size of hot water storage tank.

  5. Thermal analysis of a gas centrifuge

    International Nuclear Information System (INIS)

    Andrade, D.A.; Bastos, J.L.F.; Maiorino, J.R.

    1996-01-01

    The centrifuge separation efficiency is the result of the composition of the centrifuge field to the secondary flow in the axial direction near to the rotor wall. For a given machine, the centrifuge field can not be altered and the effort to augment the separation efficiency should be concentrated on the secondary flow. The secondary flow has a mechanical and a thermal component. The mechanical component is due to the deceleration of the gas at the scoop region. The thermal component is due to the temperature differences at the rotor. This paper presents a thermal model of a centrifuge in order to understand the main heat transfer mechanisms and to establish the boundary conditions for a fluid flow computer code. The heat transfer analysis takes into account conduction at the structure parts of the rotor and shell, radiation with multi-reflections between the rotor and the shell, and convection to the ambient. (author)

  6. Centrifugal trapping in the magnetotail

    Directory of Open Access Journals (Sweden)

    D. C. Delcourt

    1995-03-01

    Full Text Available Particles leaving the neutral sheet in the distant magnetotail at times display adiabatic trajectory sequences characterized by an inflection toward the equator and subsequent mirroring in its vicinity. We demonstrate that this low-latitude mirroring results primarily from a centrifugal deceleration due to the fast direction-changing E×B drift. This effect which we refer to as "centrifugal trapping" appears both in guiding centre and full particle treatments. It thus does not directly relate to nonadiabatic motion. However, pitch angle scattering due to nonadiabatic neutral sheet interaction does play a role in reducing the parallel speed of the particles. We show that centrifugal trapping is an important mechanism for the confinement of the slowest (typically below the equatorial E×B drift speed plasma sheet populations to the midplane vicinity.

  7. The Marine Stewardship Council (MSC) and the Making of a Market for ‘Sustainable Fish’

    DEFF Research Database (Denmark)

    Ponte, Stefano

    2012-01-01

    the market for ‘sustainable fish’, but success has been accompanied by serious challenges. The MSC has so far failed to convincingly show that its certification system has positive environmental impacts, and it has marginalized Southern fisheries, especially in low-income countries. As an institutional...... solution to the global fishery crisis, the MSC seems to be better tuned to the creation of a market for ‘sustainable fish’ rather than ‘sustainable fisheries’....

  8. A New Optimization Method for Centrifugal Compressors Based on 1D Calculations and Analyses

    Directory of Open Access Journals (Sweden)

    Pei-Yuan Li

    2015-05-01

    Full Text Available This paper presents an optimization design method for centrifugal compressors based on one-dimensional calculations and analyses. It consists of two parts: (1 centrifugal compressor geometry optimization based on one-dimensional calculations and (2 matching optimization of the vaned diffuser with an impeller based on the required throat area. A low pressure stage centrifugal compressor in a MW level gas turbine is optimized by this method. One-dimensional calculation results show that D3/D2 is too large in the original design, resulting in the low efficiency of the entire stage. Based on the one-dimensional optimization results, the geometry of the diffuser has been redesigned. The outlet diameter of the vaneless diffuser has been reduced, and the original single stage diffuser has been replaced by a tandem vaned diffuser. After optimization, the entire stage pressure ratio is increased by approximately 4%, and the efficiency is increased by approximately 2%.

  9. Safety aspects of gas centrifuge enrichment plants

    International Nuclear Information System (INIS)

    Hansen, A.H.

    1987-01-01

    Uranium enrichment by gas centrifuge is a commercially proven, viable technology. Gas centrifuge enrichment plant operations pose hazards that are also found in other industries as well as unique hazards as a result of processing and handling uranium hexafluoride and the handling of enriched uranium. Hazards also found in other industries included those posed by the use of high-speed rotating equipment and equipment handling by use of heavy-duty cranes. Hazards from high-speed rotating equipment are associated with the operation of the gas centrifuges themselves and with the operation of the uranium hexafluoride compressors in the tail withdrawal system. These and related hazards are discussed. It is included that commercial gas centrifuge enrichment plants have been designed to operate safely

  10. Centrifugal Casting Features/Metallurgical Characterization of Aluminum Alloys

    International Nuclear Information System (INIS)

    Chirita, G.; Soares, D.; Cruz, D.; Silva, F. S.; Stefanescu, I.

    2008-01-01

    This paper deals with the study of centrifugal effects on aluminium castings under high G values. Most of the studies in this domain (FGMs obtained by centrifugal casting) deal with functionally graded composites reinforced with a solid phase such as silicon particles or others. However, in this study it will be shown that unreinforced aluminium alloys may be significantly influenced by the centrifugal effect and that functionally graded castings are also obtained. It has been observed that the centrifugal effect may increase in some alloys, depending on the relative position in the castings, the rupture strength by approx. 50%, and rupture strain by about 300%, as compared to the gravity casting technique. The Young's modulus may also increase by about 20%. It has also been reported that in vertical centrifugal castings there are mainly three aspects that affect the components thus obtained, namely: fluid dynamics; vibration (inherent to the system); and centrifugal force. These features have a different effect on the castings depending on the aluminium alloy. In this paper, an analysis of the most important effects of the centrifugal casting process on metallurgical features is conducted. A solidification characterization at several points along the mould will be made in order to have an accurate idea of both the fluid dynamics inside the mould during the casting and the solidification behavior in different parts of the component. These two analyses will be related to the metallurgical properties (phase distribution; SDAS; eutectic silicon content and shape, pores density and shape) along the component and mainly along the direction of the centrifugal pressure. A comparison between castings obtained by both centrifugal casting technique and gravity casting technique is made for reference (gravity casting)

  11. Improved g-level calculations for coil planet centrifuges.

    Science.gov (United States)

    van den Heuvel, Remco N A M; König, Carola S

    2011-09-09

    Calculation of the g-level is often used to compare CCC centrifuges, either against each other or to allow for comparison with other centrifugal techniques. This study shows the limitations of calculating the g-level in the traditional way. Traditional g-level calculations produce a constant value which does not accurately reflect the dynamics of the coil planet centrifuge. This work has led to a new equation which can be used to determine the improved non-dimensional values. The new equations describe the fluctuating radial and tangential g-level associated with CCC centrifuges and the mean radial g-level value. The latter has been found to be significantly different than that determined by the traditional equation. This new equation will give a better understanding of forces experienced by sample components and allows for more accurate comparison between centrifuges. Although the new equation is far better than the traditional equation for comparing different types of centrifuges, other factors such as the mixing regime may need to be considered to improve the comparison further. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. In vivo MR detection of fluorine-labeled human MSC using the bSSFP sequence.

    Science.gov (United States)

    Ribot, Emeline J; Gaudet, Jeffrey M; Chen, Yuhua; Gilbert, Kyle M; Foster, Paula J

    2014-01-01

    Mesenchymal stem cells (MSC) are used to restore deteriorated cell environments. There is a need to specifically track these cells following transplantation in order to evaluate different methods of implantation, to follow their migration within the body, and to quantify their accumulation at the target. Cellular magnetic resonance imaging (MRI) using fluorine-based nanoemulsions is a great means to detect these transplanted cells in vivo because of the high specificity for fluorine detection and the capability for precise quantification. This technique, however, has low sensitivity, necessitating improvement in MR sequences. To counteract this issue, the balanced steady-state free precession (bSSFP) imaging sequence can be of great interest due to the high signal-to-noise ratio (SNR). Furthermore, it can be applied to obtain 3D images within short acquisition times. In this paper, bSSFP provided accurate quantification of samples of the perfluorocarbon Cell Sense-labeled cells in vitro. Cell Sense was internalized by human MSC (hMSC) without adverse alterations in cell viability or differentiation into adipocytes/osteocytes. The bSSFP sequence was applied in vivo to track and quantify the signals from both Cell Sense-labeled and iron-labeled hMSC after intramuscular implantation. The fluorine signal was observed to decrease faster and more significantly than the volume of iron-associated voids, which points to the advantage of quantifying the fluorine signal and the complexity of quantifying signal loss due to iron.

  13. Matrix metalloproteinase-1 facilitates MSC migration via cleavage of IGF-2/IGFBP2 complex.

    Science.gov (United States)

    Guan, Shou P; Lam, Alan T L; Newman, Jennifer P; Chua, Kevin L M; Kok, Catherine Y L; Chong, Siao T; Chua, Melvin L K; Lam, Paula Y P

    2018-01-01

    The specific mechanism underlying the tumor tropism of human mesenchymal stem cells (MSCs) for cancer is not well defined. We previously showed that the migration potential of MSCs correlated with the expression and protease activity of matrix metalloproteinase (MMP)-1. Furthermore, highly tumor-tropic MSCs expressed higher levels of MMP-1 and insulin-like growth factor (IGF)-2 than poorly migrating MSCs. In this study, we examined the functional roles of IGF-2 and MMP-1 in mediating the tumor tropism of MSCs. Exogenous addition of either recombinant IGF-2 or MMP-1 could stimulate MSC migration. The correlation between IGF-2, MMP-1 expression, and MSC migration suggests that MMP-1 may play a role in regulating MSC migration via the IGF-2 signaling cascade. High concentrations of IGF binding proteins (IGFBPs) can inhibit IGF-stimulated functions by blocking its binding to its receptors and proteolysis of IGFBP is an important mechanism for the regulation of IGF signaling. We thus hypothesized that MMP-1 acts as an IGFBP2 proteinase, resulting in the cleavage of IGF-2/IGFBP2 complex and extracellular release of free IGF-2. Indeed, our results showed that conditioned media from highly migrating MSCs, which expressed high levels of MMP-1, cleaved the IGF-2/IGFBP2 complex. Taken together, these results showed that the MMP-1 secreted by highly tumor-tropic MSCs cleaved IGF-2/IGFBP2 complex. Free IGF-2 released from the complex may facilitate MSC migration toward tumor.

  14. Functional properties of meat by-products and mechanically separated chicken (MSC) in a high-moisture model petfood system.

    Science.gov (United States)

    Rivera, J A; Sebranek, J G; Rust, R E

    2000-05-01

    Contributions to water retention capacity (% WRC) and texture changes were determined for pork by-products (lung lobes, kidneys), chicken viscera (head, feet and viscera) and mechanically separated chicken (MSC) as affected by pH and various salts in a high-moisture model system. The % WRC for meat by-products and MSC was increased by increased pH (4.5-6.8). Pork lungs and MSC had the highest % WRC (pmeat by-products. Meat by-product % WRC was not signifcantly (p>0.05) affected by salt (2%), phosphate (0.3%) or NaOH (0.075%). Chicken viscera had the lowest (pmeat by-products and MSC. Strong negative correlations (p<0.05) were obtained for texture with total collagen, soluble collagen and high ionic strength soluble (HIS) proteins. These results should be considered for product quality changes when these by-products are used in formulation of high moisture pet food products.

  15. [The analytical setting of rotary speed of centrifuge rotor and centrifugation time in chemical, biochemical and microbiological practice].

    Science.gov (United States)

    Zolotarev, K V

    2012-08-01

    The researchers happen to face with suspensions in their chemical, biochemical and microbiological practice. The suspensions are the disperse systems with solid dispersed phase and liquid dispersion medium and with dispersed phase particle size > 100 nm (10-7 m). Quite often the necessity occurs to separate solid particles from liquid. To use for this purpose the precipitation in gravitation field can make the process to progress too long. In this respect an effective mode is the precipitation in the field of centrifugal forces--the centrifugation. The rotary speed of centrifuge rotor and centrifugation time can be set analytically using regularities of general dynamics and hydrodynamics. To this effect, should be written and transformed the equation of First and Second Newton Laws for suspension particle being in the field of centrifugal forces and forces of resistance of liquid and vessel wall. The force of liquid resistance depends on particle motion condition in liquid. To determine the regimen the Archimedes and Reynolds numerical dimensionless criteria are to be applied. The article demonstrates the results of these transformations as analytical inverse ratio dependence of centrifugation time from rotary speed. The calculation of series of "rate-time" data permits to choose the optimal data pair on the assumption of centrifuge capacity and practical reasonability. The results of calculations are validated by actual experimental data hence the physical mathematical apparatus can be considered as effective one. The setting progress depends both from parameter (Reynolds criterion) and data series calculation. So, the most convenient way to apply this operation is the programming approach. The article proposes to use the program Microsoft Excel and VBA programming language for this purpose. The possibility to download the file from Internet to use it for fast solution is proposed.

  16. Achieving an ever-improving centrifuge

    International Nuclear Information System (INIS)

    Edwards, T.T.; Wilcox, P.

    1988-01-01

    To ensure that the latest technical innovations can be rapidly incorporated, centrifuge development in the Urenco organization is carried out in different phases simultaneously on different generations of machines. This system has led to progressively increased outputs and reduced specific costs, and with the further known potential available, is expected to maintain Urenco's competitiveness throughout the 1990s. The process of separating isotopes by centrifuge is described. (author)

  17. Gastric cancer-derived MSC-secreted PDGF-DD promotes gastric cancer progression.

    Science.gov (United States)

    Huang, Feng; Wang, Mei; Yang, Tingting; Cai, Jie; Zhang, Qiang; Sun, Zixuan; Wu, Xiaodan; Zhang, Xu; Zhu, Wei; Qian, Hui; Xu, Wenrong

    2014-11-01

    This study was designed to investigate the role of PDGF-DD secreted by gastric cancer-derived mesenchymal stem cells (GC-MSCs) in human gastric cancer progression. Gastric cancer cells were indirectly co-cultured with GC-MSCs in a transwell system. The growth and migration of gastric cancer cells were evaluated by cell colony formation assay and transwell migration assay, respectively. The production of PDGF-DD in GC-MSCs was determined by using Luminex and ELISA. Neutralization of PDGFR-β by su16f and siRNA interference of PDGF-DD in GC-MSCs was used to demonstrate the role of PDGF-DD produced by GC-MSCs in gastric cancer progression. GC-MSC conditioned medium promoted gastric cancer cell proliferation and migration in vitro and in vivo. Co-culture with GC-MSCs increased the phosphorylation of PDGFR-β in SGC-7901 cells. Neutralization of PDGFR-β by su16f blocked the promoting role of GC-MSC conditioned medium in gastric cancer cell proliferation and migration. Recombinant PDGF-DD duplicated the effects of GC-MSC conditioned medium on gastric cancer cells. Knockdown of PDGF-DD in GC-MSCs abolished its effects on gastric cancer cells in vitro and in vivo. PDGF-DD secreted by GC-MSCs is capable of promoting gastric cancer cell progression in vitro and in vivo. Targeting the PDGF-DD/PDGFR-β interaction between MSCs and gastric cancer cells may represent a novel strategy for gastric cancer therapy.

  18. Effectiveness of cross-border knowledge transfer in Malaysian MSC status corporations

    Directory of Open Access Journals (Sweden)

    Aaron Sow Yee Pook

    2017-03-01

    Full Text Available Knowledge has become the key asset for the economy to gain competitiveness as more and more countries have shifted or are shifting towards knowledge-based economy, no exception for Malaysia. In order to acquire and transfer technology and/or knowledge from overseas to Malaysia, Multimedia Super Corridor (MSC has been proposed. However, research focuses on cross-border knowledge transfer especially in the context of MSC status corporations in Malaysia is still limited. The factors that affect the effectiveness of cross-border knowledge transfer will be determined and presented in this paper. Quantitative approach has been adopted in this study. The findings of this study show that knowledge characteristics (KC and network characteristics (NC have positive significant relationship with cross-border knowledge transfer. The effects context towards KC and NC will also be examined in this study.

  19. Rhie-Chow interpolation in strong centrifugal fields

    Science.gov (United States)

    Bogovalov, S. V.; Tronin, I. V.

    2015-10-01

    Rhie-Chow interpolation formulas are derived from the Navier-Stokes and continuity equations. These formulas are generalized to gas dynamics in strong centrifugal fields (as high as 106 g) occurring in gas centrifuges.

  20. Education of MSc and PhD Students in Fluid Power and Mechatronics at DTU

    DEFF Research Database (Denmark)

    Conrad, Finn

    1996-01-01

    The paper deals with education of MSc and PhD students in engineering areas fluid power and mechatronics at the Technical Univ of Denmark, DTU, Lyngby. The new education structure and programs for MSc and PhD students adapted to the change and development of technologies. Focus is on two of twenty...... engineering profilies:(1) Engineeing Design and Product Development and (2)Control Engineering which give possibilitie for specialisation in fluid power and mechatronics design and productdevelopment. Synthesis, design and self-learning competency have a high priority taking the importance of training...

  1. Effective treatment of steroid and therapy-refractory acute graft-versus-host disease with a novel mesenchymal stromal cell product (MSC-FFM).

    Science.gov (United States)

    Bader, Peter; Kuçi, Zyrafete; Bakhtiar, Shahrzad; Basu, Oliver; Bug, Gesine; Dennis, Michael; Greil, Johann; Barta, Aniko; Kállay, Krisztián M; Lang, Peter; Lucchini, Giovanna; Pol, Raj; Schulz, Ansgar; Sykora, Karl-Walter; von Luettichau, Irene; Herter-Sprie, Grit; Uddin, Mohammad Ashab; Jenkin, Phil; Alsultan, Abdulrahman; Buechner, Jochen; Stein, Jerry; Kelemen, Agnes; Jarisch, Andrea; Soerensen, Jan; Salzmann-Manrique, Emilia; Hutter, Martin; Schäfer, Richard; Seifried, Erhard; Klingebiel, Thomas; Bonig, Halvard; Kuçi, Selim

    2018-01-29

    The inability to generate mesenchymal stromal cells (MSCs) of consistent potency likely is responsible for inconsistent clinical outcomes of patients with aGvHD receiving MSC products. We developed a novel MSC manufacturing protocol characterized by high in vitro potency and near-identity of individual doses, referred to as "MSC-Frankfurt am Main (MSC-FFM)". Herein, we report outcomes of the 69 patients who have received MSC-FFM. These were 51 children and 18 adults with refractory aGvHD grade II (4%), III (36%) or IV (59%). Patients were refractory either to frontline therapy (steroids) (29%) or to steroids and 1-5 additional lines of immunosuppressants (71%) were given infusions in four weekly intervals. The day 28 overall response rate was 83%; at the last follow-up, 61% and 25% of patients were in complete or partial remission. The median follow-up was 8.1 months. Six-month estimate for cumulative incidence of non-relapse mortality was 27% (range, 16-38); leukemia relapse mortality was 2% (range, 0-5). This was associated with a superior six-month overall survival (OS) probability rate of 71% (range, 61-83), compared to the outcome of patients not treated with MSC-FFM. This novel product was effective in children and adults, suggesting that MSC-FFM represents a promising therapy for steroid refractory aGvHD.

  2. Centrifuge modelling of offshore monopile foundation

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte; Hededal, Ole

    2010-01-01

    centrifuge tests on a laterally loaded monopile in dry sand. The prototype dimension of the piles was modelled to a diameter of 1 meter and penetration depth on 6 meter. The test series were designed in order to investigate the scaling laws in the centrifuge both for monotonic and cyclic loading...

  3. Chimeras Reveal a Single Lipid-Interface Residue that Controls MscL Channel Kinetics as well as Mechanosensitivity

    Directory of Open Access Journals (Sweden)

    Li-Min Yang

    2013-02-01

    Full Text Available MscL, the highly conserved bacterial mechanosensitive channel of large conductance, serves as an osmotic “emergency release valve,” is among the best-studied mechanosensors, and is a paradigm of how a channel senses and responds to membrane tension. Although all homologs tested thus far encode channel activity, many show functional differences. We tested Escherichia coli and Staphylococcus aureus chimeras and found that the periplasmic region of the protein, particularly E. coli I49 and the equivalent S. aureus F47 at the periplasmic lipid-aqueous interface of the first transmembrane domain, drastically influences both the open dwell time and the threshold of channel opening. One mutant shows a severe hysteresis, confirming the importance of this residue in determining the energy barriers for channel gating. We propose that this site acts similarly to a spring for a clasp knife, adjusting the resistance for obtaining and stabilizing an open or closed channel structure.

  4. Modeling centrifugal cell washers using computational fluid dynamics.

    Science.gov (United States)

    Kellet, Beth E; Han, Binbing; Dandy, David S; Wickramasinghe, S Ranil

    2004-11-01

    Reinfusion of shed blood during surgery could avoid the need for blood transfusions. Prior to reinfusion of the red blood cells, the shed blood must be washed in order to remove leukocytes, platelets, and other contaminants. Further, the hematocrit of the washed blood must be increased. The feasibility of using computational fluid dynamics (CFD) to guide the design of better centrifuges for processing shed blood is explored here. The velocity field within a centrifuge bowl and the rate of protein removal from the shed blood has been studied. The results obtained indicate that CFD could help screen preliminary centrifuge bowl designs, thus reducing the number of initial experimental tests required when developing new centrifuge bowls. Although the focus of this work is on washing shed blood, the methods developed here are applicable to the design of centrifuge bowls for other blood-processing applications.

  5. Decontamination of nuclear fuels with centrifugal separation

    International Nuclear Information System (INIS)

    Ning, Li; Camassa, R.; Ecke, R.; Venneri, F.

    1995-01-01

    The treatment and disposal of nuclear material is a crucial element in today's nuclear power industry. We present a physical process of centrifugal separation that has potential to deal with existing waste and provide opportunities for realizing advanced accelerator-driven power generation. In our proposed process a liquid metal solution containing actinides and fission products is fed through a series of continuous flow centrifuges. We show fundamentals of centrifugation including theory and experiments and estimate how the processing can be optimized

  6. Decontamination of nuclear fuels with centrifugal separation

    International Nuclear Information System (INIS)

    Ning, L.; Camassa, R.; Ecke, R.; Venneri, F.

    1995-01-01

    The treatment and disposal of nuclear material is a crucial element in today's nuclear power industry. We present a physical process of centrifugal separation that has potential to deal with existing waste and provide opportunities for realizing advanced accelerator driven power generation. In our proposed process a liquid metal solution containing actinides and fission products is fed through a series of continuous flow centrifuges. We show fundamentals of centrifugation including theory and experiments and estimate how the processing can be optimized. (authors)

  7. Aiming for outstanding: Action research from students of the MSc in the Teaching of Psychology

    OpenAIRE

    Lintern, Fiona; Davies, Jamie; McGinty, Andrew; Fisher, Jeannine

    2014-01-01

    The first cohort of a new MSc programme is due to complete the course in August 2014. During the three-year online course students conduct several pieces of action research in their classrooms. There is little research specifically related classroom practice in the pre-tertiary psychology classroom. The following describes the rationale and context of the MSc in the Teaching of Psychology and reports on three students’ final year research. The first considers the benefits of Psychology Applie...

  8. Centrifugal trapping in the magnetotail

    Directory of Open Access Journals (Sweden)

    D. C. Delcourt

    Full Text Available Particles leaving the neutral sheet in the distant magnetotail at times display adiabatic trajectory sequences characterized by an inflection toward the equator and subsequent mirroring in its vicinity. We demonstrate that this low-latitude mirroring results primarily from a centrifugal deceleration due to the fast direction-changing E×B drift. This effect which we refer to as "centrifugal trapping" appears both in guiding centre and full particle treatments. It thus does not directly relate to nonadiabatic motion. However, pitch angle scattering due to nonadiabatic neutral sheet interaction does play a role in reducing the parallel speed of the particles. We show that centrifugal trapping is an important mechanism for the confinement of the slowest (typically below the equatorial E×B drift speed plasma sheet populations to the midplane vicinity.

  9. An Experimental Study of Cavitation Detection in a Centrifugal Pump Using Envelope Analysis

    Science.gov (United States)

    Tan, Chek Zin; Leong, M. Salman

    Cavitation represents one of the most common faults in pumps and could potentially lead to a series of failure in mechanical seal, impeller, bearing, shaft, motor, etc. In this work, an experimental rig was setup to investigate cavitation detection using vibration envelope analysis method, and measured parameters included sound, pressure and flow rate for feasibility of cavitation detection. The experiment testing included 3 operating points of the centrifugal pump (B.E.P, 90% of B.E.P and 80% of B.E.P). Suction pressure of the centrifugal pump was decreased gradually until the inception point of cavitation. Vibration measurements were undertaken at various locations including casing, bearing, suction and discharge flange of the centrifugal pump. Comparisons of envelope spectrums under cavitating and non-cavitating conditions were presented. Envelope analysis was proven useful in detecting cavitation over the 3 testing conditions. During the normal operating condition, vibration peak synchronous to rotational speed was more pronounced. It was however during cavitation condition, the half order sub-harmonic vibration component was clearly evident in the envelope spectrums undertaken at all measurement locations except at the pump bearing. The possible explanation of the strong sub-harmonic (½ of BPF) during cavitation existence in the centrifugal pump was due to insufficient time for the bubbles to collapse completely before the end of the single cycle.

  10. Effect of Centrifuge Temperature on Routine Coagulation Tests.

    Science.gov (United States)

    Yazar, Hayrullah; Özdemir, Fatma; Köse, Elif

    2018-01-01

    This study investigated the effects of cooled and standard centrifuges on the results of coagulation tests to examine the effects of centrifugation temperature. Equal-volume blood samples from each patient were collected at the same time intervals and subjected to standard (25°C) and cooled centrifugation (2-4°C). Subsequently, the prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen, and D-dimer values were determined in runs with the same lot numbers in the same coagulation device using the Dia-PT R (PT and INR), Dia-PTT-liquid (aPTT), Dia-FIB (fibrinogen), and Dia-D-dimer kits, respectively. The study enrolled 771 participants. The PT was significantly (p centrifuges were as follows: PT 10.30 versus 10.50 s; PT (INR) 1.04 versus 1.09 s; APTT 28.90 versus 29.40 s; fibrinogen 321.5 versus 322.1 mg/dL; and D-dimer 179.5 versus 168.7 µg FEU/mL. There were significant differences (p centrifuges. Centrifuge temperature can have a significant effect on the results of coagulation tests. However, broad and specific disease-based studies are needed. © 2018 S. Karger AG, Basel.

  11. A wireless high-speed data acquisition system for geotechnical centrifuge model testing

    Science.gov (United States)

    Gaudin, C.; White, D. J.; Boylan, N.; Breen, J.; Brown, T.; DeCatania, S.; Hortin, P.

    2009-09-01

    This paper describes a novel high-speed wireless data acquisition system (WDAS) developed at the University of Western Australia for operation onboard a geotechnical centrifuge, in an enhanced gravitational field of up to 300 times Earth's gravity. The WDAS system consists of up to eight separate miniature units distributed around the circumference of a 0.8 m diameter drum centrifuge, communicating with the control room via wireless Ethernet. Each unit is capable of powering and monitoring eight instrument channels at a sampling rate of up to 1 MHz at 16-bit resolution. The data are stored within the logging unit in solid-state memory, but may also be streamed in real-time at low frequency (up to 10 Hz) to the centrifuge control room, via wireless transmission. The high-speed logging runs continuously within a circular memory (buffer), allowing for storage of a pre-trigger segment of data prior to an event. To suit typical geotechnical modelling applications, the system can record low-speed data continuously, until a burst of high-speed acquisition is triggered when an experimental event occurs, after which the system reverts back to low-speed acquisition to monitor the aftermath of the event. Unlike PC-based data acquisition solutions, this system performs the full sequence of amplification, conditioning, digitization and storage on a single circuit board via an independent micro-controller allocated to each pair of instrumented channels. This arrangement is efficient, compact and physically robust to suit the centrifuge environment. This paper details the design specification of the WDAS along with the software interface developed to control the units. Results from a centrifuge test of a submarine landslide are used to illustrate the performance of the new WDAS.

  12. A wireless high-speed data acquisition system for geotechnical centrifuge model testing

    International Nuclear Information System (INIS)

    Gaudin, C; White, D J; Boylan, N; Breen, J; Brown, T; De Catania, S; Hortin, P

    2009-01-01

    This paper describes a novel high-speed wireless data acquisition system (WDAS) developed at the University of Western Australia for operation onboard a geotechnical centrifuge, in an enhanced gravitational field of up to 300 times Earth's gravity. The WDAS system consists of up to eight separate miniature units distributed around the circumference of a 0.8 m diameter drum centrifuge, communicating with the control room via wireless Ethernet. Each unit is capable of powering and monitoring eight instrument channels at a sampling rate of up to 1 MHz at 16-bit resolution. The data are stored within the logging unit in solid-state memory, but may also be streamed in real-time at low frequency (up to 10 Hz) to the centrifuge control room, via wireless transmission. The high-speed logging runs continuously within a circular memory (buffer), allowing for storage of a pre-trigger segment of data prior to an event. To suit typical geotechnical modelling applications, the system can record low-speed data continuously, until a burst of high-speed acquisition is triggered when an experimental event occurs, after which the system reverts back to low-speed acquisition to monitor the aftermath of the event. Unlike PC-based data acquisition solutions, this system performs the full sequence of amplification, conditioning, digitization and storage on a single circuit board via an independent micro-controller allocated to each pair of instrumented channels. This arrangement is efficient, compact and physically robust to suit the centrifuge environment. This paper details the design specification of the WDAS along with the software interface developed to control the units. Results from a centrifuge test of a submarine landslide are used to illustrate the performance of the new WDAS

  13. Development of uranium enrichment technology by gas centrifugation

    International Nuclear Information System (INIS)

    Sibata, Tomofumi; Kai, Tsunetoshi

    1996-01-01

    The development of a gas-centrifuge for uranium enrichment has been conducted by Power Reactor and Nuclear Fuel Development Corporation in Japan after the first several years' fruitless works, the R and D works came to the point and continuing rapid improvements of centrifuges have started, Cascade tests were given with C-1 and C-2 cascade experimental facilities. Life, reliability and feasibility tests were given with the pilot plant and the demonstration plant. As a result of these works, the private commercial plant has started the operation. Although the main efforts were devoted to the development of metal rotor centrifuges in the course mentioned above, composite material rotor centrifuges have also been developed in parallel to achieve higher performance. Promising results have been being obtained with cascade test facilities on the pilot plant scale. Furthermore, R and D works are being proceeded on more excellent and advanced centrifuges. (author)

  14. Isotopic enrichment in a plasma centrifuge

    International Nuclear Information System (INIS)

    Del Bosco, E.; Dallaqua, R.S.; Ludwig, G.O.; Bittencourt, J.A.

    1987-01-01

    High rotational velocity and centrifugal isotopic separation of carbon in a vacuum-arc plasma centrifuge are presented. Enrichments of up to 390% for 13 C are measured at 6 cm radius with angular rotation frequencies in excess of 1.0 x 10 5 rad/s in an axial magnetic field of 0.12 T

  15. Research on the development of the centrifugal spinning

    Directory of Open Access Journals (Sweden)

    Zhang Zhiming

    2017-01-01

    Full Text Available Centrifugal spinning is a new and efficient method to produce nanofibers quickly. It makes use of the centrifugal force instead of high voltage to produce the nanofibers. The centrifugal spinning has many advantages such as no high voltage, high yield, simple structure, no pollution and can be applied to high polymer material, ceramic and metal material. In order to have more understand about this novel nanofibers formation method, this paper introduces the method of centrifugal spinning and the effect of rotation speed, the properties of material such as viscosity and solvent evaporation, collector distance which have an impact on nanofibers morphology and diameter were also analyzed.

  16. Engineering design of centrifugal casting machine

    Science.gov (United States)

    Kusnowo, Roni; Gunara, Sophiadi

    2017-06-01

    Centrifugal casting is a metal casting process in which metal liquid is poured into a rotating mold at a specific temperature. Given round will generate a centrifugal force that will affect the outcome of the casting. Casting method is suitable in the manufacture of the casting cylinder to obtain better results. This research was performed to design a prototype machine by using the concept of centrifugal casting. The design method was a step-by-step systematic approach in the process of thinking to achieve the desired goal of realizing the idea and build bridges between idea and the product. Design process was commenced by the conceptual design phase and followed by the embodiment design stage and detailed design stage. With an engineering design process based on the method developed by G. E. Dieter, draft prototype of centrifugal casting machine with dimension of 550×450×400 mm, ¼ HP motor power, pulley and belt mechanism, diameter of 120-150mm, simultaneously with the characteristics of simple casting product, easy manufacture and maintenance, and relatively inexpensive, was generated.

  17. Gas dynamics in strong centrifugal fields

    Energy Technology Data Exchange (ETDEWEB)

    Bogovalov, S.V.; Kislov, V.A.; Tronin, I.V. [National research nuclear university “MEPhI”, Kashirskoje shosse, 31,115409, Moscow (Russian Federation)

    2015-03-10

    Dynamics of waves generated by scopes in gas centrifuges (GC) for isotope separation is considered. The centrifugal acceleration in the GC reaches values of the order of 106g. The centrifugal and Coriolis forces modify essentially the conventional sound waves. Three families of the waves with different polarisation and dispersion exist in these conditions. Dynamics of the flow in the model GC Iguasu is investigated numerically. Comparison of the results of the numerical modelling of the wave dynamics with the analytical predictions is performed. New phenomena of the resonances in the GC is found. The resonances occur for the waves polarized along the rotational axis having the smallest dumping due to the viscosity.

  18. The American Gas Centrifuge Past, Present, and Future

    Energy Technology Data Exchange (ETDEWEB)

    Waters, Dean

    2004-09-15

    The art of gas centrifugation was born in 1935 at the University of Virginia when Dr. Jesse Beams demonstrated experimentally the separation of chlorine isotopes using an ultra-high speed centrifuge. Dr. Beam’s experiment initiated work that created a rich history of scientific and engineering accomplishment in the United States in the art of isotope separation and even large scale biological separation by centrifugation. The early history of the gas centrifuge development was captured in a lecture and documented by Dr. Jesse Beams in 1975. Much of Dr. Beams lecture material is used in this paper up to the year 1960. Following work by Dr. Gernot Zippe at the University of Virginia between 1958 and 1960, the US government embarked on a centrifuge development program that ultimately led to the start of construction of the Gas Centrifuge Enrichment Plant in Piketon Ohio in the late 1970’s. The government program was abandoned in 1985 after investing in the construction of two of six planned process buildings, a complete supply chain for process and centrifuge parts, and the successful manufacture and brief operation of an initial complement of production machines that would have met 15 percent of the planned capacity of the constructed process buildings. A declining market for enriched uranium, a glut of uranium enrichment capacity worldwide, and the promise of a new laser based separation process factored in the decision to stop the government program. By the late 1990’s it had become evident that gas centrifugation held the best promise to produce enriched uranium at low cost. In1999, the United States Enrichment Corporation undertook an initiative to revive the best of the American centrifuge technology that had been abandoned fourteen years earlier. This is an exciting story and one that when complete will enable the United States to maintain its domestic supply and to be highly competitive in the world market for this important energy commodity. (auth)

  19. Detection methods for centrifugal microfluidic platforms

    DEFF Research Database (Denmark)

    Burger, Robert; Amato, Letizia; Boisen, Anja

    2016-01-01

    Centrifugal microfluidics has attracted much interest from academia as well as industry, since it potentially offers solutions for affordable, user-friendly and portable biosensing. A wide range of so-called fluidic unit operations, e.g. mixing, metering, liquid routing, and particle separation...... for the centrifugal microfluidics platform and cover optical as well as mechanical and electrical detection principles....

  20. Plasma instability of a vacuum arc centrifuge

    International Nuclear Information System (INIS)

    Hole, M.J.; Dallaqua, R.S.; Simpson, S.W.; Del Bosco, E.

    2002-01-01

    Ever since conception of the vacuum arc centrifuge in 1980, periodic fluctuations in the ion saturation current and floating potential have been observed in Langmuir probe measurements in the rotation region of a vacuum arc centrifuge. In this work we develop a linearized theoretical model to describe a range of instabilities in the vacuum arc centrifuge plasma column, and then test the validity of the description through comparison with experiment. We conclude that the observed instability is a 'universal' instability, driven by the density gradient, in a plasma with finite conductivity

  1. Modern gas centrifuge and rarefied-gas dynamics

    International Nuclear Information System (INIS)

    Lowry, R.A.; Halle, E.V.; Wood, H.G. III.

    1981-01-01

    Today, the modern gas centrifuge appears to be the preferred method for the enrichment of the isotopes of uranium on a commercial scale. That this is the case is the result of diligent development programs pursued in this country as well as in the UK, Germany, and the Netherlands over the several decades since the end of WW II. The theoretical modelling of gas centrifuge performance has made notable advances. However, the theoretical work has been based primarily on continuum fluid dynamics considerations. Centrifuge problems involving rarefied gas dynamics considerations are discussed in this paper

  2. Linearized thin-wing theory of gas-centrifuge scoops

    International Nuclear Information System (INIS)

    Sakurai, T.

    1981-01-01

    A steady hypersonic rotating flow of a perfect gas past a system of thin stationary scoops in a gas centrifuge of annulus type is studied. The gas is assumed inviscid; its ratio of specific heats is assumed to be approximately 1. The scoops are set at zero angle of attack and are periodic with respect to the azimuthal variable. The flow is assumed to be a three-dimensional small perturbation on a basic state of rigid-body rotation. New scaling laws are proposed as appropriate to realistic operating conditions of gas centrifuges. Basic equations, boundary conditions and shock conditions are linearized for a weakly hypersonic flow by an analytical procedure similar to that used in the thin-wing approximation in high speed aerodynamics. The solution of the basic equations is obtained by the eigenfunction expansion method. The solution provides a simple addition theorem for the scoop drag which makes the resultant drag of a system of several scoops equal to the product of the number of scoops and the drag of a standard system with a single scoop. The solution makes it clear that despite the above addition theorem, the scoops interact in their effects on the flow. (author)

  3. Advanced finite element simulation with MSC Marc application of user subroutines

    CERN Document Server

    Javanbakht, Zia

    2017-01-01

    This book offers an in-depth insight into the general-purpose finite element program MSC Marc, which is distributed by MSC Software Corporation. It is a specialized program for nonlinear problems (implicit solver) which is common in academia and industry. The primary goal of this book is to provide a comprehensive introduction to a special feature of this software: the user can write user-subroutines in the programming language Fortran, which is the language of all classical finite element packages. This subroutine feature allows the user to replace certain modules of the core code and to implement new features such as constitutive laws or new elements. Thus, the functionality of commercial codes (‘black box’) can easily be extended by linking user written code to the main core of the program. This feature allows to take advantage of a commercial software package with the flexibility of a ‘semi-open’ code. .

  4. Subjective stress factors in centrifuge training for military aircrews.

    Science.gov (United States)

    Lin, Pei-Chun; Wang, Jenhung; Li, Shih-Chin

    2012-07-01

    This study investigates stress-influence factors perceived by military aircrews undergoing centrifuge training, which lowers the incidence of G-induced loss of consciousness (G-LOC) for the crews of high-performance combat aircrafts. We used questionnaires to assess the subjective stress-influence factors of crews undergoing centrifuge training. Professionals in aviation physiology identified attributes measuring the perceived stress induced by centrifuge training, which were segmented into three constructs by factor analysis, theory lecture, centrifuge equipment, and physical fitness. Considerable interpenetration was discernible between these factors and military rank, age, length of service, flight hours accrued, and type of aircraft piloted. Identifying and quantifying the perceived stressors experienced in human-use centrifuge training enables aviators, astronauts, and air forces of the world to determine which constructs perceptibly increase or alleviate the perceived stress undergone by trainees when partaking in centrifuge training. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  5. Bifurcated equilibria in centrifugally confined plasma

    International Nuclear Information System (INIS)

    Shamim, I.; Teodorescu, C.; Guzdar, P. N.; Hassam, A. B.; Clary, R.; Ellis, R.; Lunsford, R.

    2008-01-01

    A bifurcation theory and associated computational model are developed to account for abrupt transitions observed recently on the Maryland Centrifugal eXperiment (MCX) [R. F. Ellis et al. Phys. Plasmas 8, 2057 (2001)], a supersonically rotating magnetized plasma that relies on centrifugal forces to prevent thermal expansion of plasma along the magnetic field. The observed transitions are from a well-confined, high-rotation state (HR-mode) to a lower-rotation, lesser-confined state (O-mode). A two-dimensional time-dependent magnetohydrodynamics code is used to simulate the dynamical equilibrium states of the MCX configuration. In addition to the expected viscous drag on the core plasma rotation, a momentum loss term is added that models the friction of plasma on the enhanced level of neutrals expected in the vicinity of the insulators at the throats of the magnetic mirror geometry. At small values of the external rotation drive, the plasma is not well-centrifugally confined and hence experiences the drag from near the insulators. Beyond a critical value of the external drive, the system makes an abrupt transition to a well-centrifugally confined state in which the plasma has pulled away from the end insulator plates; more effective centrifugal confinement lowers the plasma mass near the insulators allowing runaway increases in the rotation speed. The well-confined steady state is reached when the external drive is balanced by only the viscosity of the core plasma. A clear hysteresis phenomenon is shown.

  6. Centrifugal acceleration in the magnetotail lobes

    Directory of Open Access Journals (Sweden)

    H. Nilsson

    2010-02-01

    Full Text Available Combined Cluster EFW and EDI measurements have shown that cold ion outflow in the magnetospheric lobes dominates the hydrogen ion outflow from the Earth's atmosphere. The ions have too low kinetic energy to be measurable with particle instruments, at least for the typical spacecraft potential of a sunlit spacecraft in the tenuous lobe plasmas outside a few RE. The measurement technique yields both density and bulk velocity, which can be combined with magnetic field measurements to estimate the centrifugal acceleration experienced by these particles. We present a quantitative estimate of the centrifugal acceleration, and the velocity change with distance which we would expect due to centrifugal acceleration. It is found that the centrifugal acceleration is on average outward with an average value of about of 5 m s−2. This is small, but acting during long transport times and over long distances the cumulative effect is significant, while still consistent with the relatively low velocities estimated using the combination of EFW and EDI data. The centrifugal acceleration should accelerate any oxygen ions in the lobes to energies observable by particle spectrometers. The data set also put constraints on the effectiveness of any other acceleration mechanisms acting in the lobes, where the total velocity increase between 5 and 19 RE geocentric distance is less than 5 km s−1.

  7. Theory of uranium enrichment by the gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Olander, D R [California Univ., Berkeley (USA). Lawrence Berkeley Lab.; California Univ., Berkeley (USA). Dept. of Nuclear Engineering)

    1981-01-01

    Onsager's analysis of the hydrodynamics of fluid circulation in the boundary layer on the rotor wall of a gas centrifuge is reviewed. The description of the flow in the boundary layers on the top and bottom end caps due to Carrier and Maslen is summarized. The method developed by Wood and Morton of coupling the flow models in the rotor wall and end cap boundary layers to complete the hydrodynamic analysis of the centrifuge is presented. Mechanical and thermal methods of driving the internal gas circulation are described. The isotope enrichment which results from the superposition of the elementary separation effect due to the centrifugal field in the gas and its internal circulation is analyzed by the Onsager-Cohen theory. The performance function representing the optimized separative power of a centrifuge as a function of throughput and cut is calculated for several simplified internal flow models. The use of asymmetric ideal cascades to exploit the distinctive features of centrifuge performance functions is illustrated.

  8. Surface-Enhanced Raman Spectroscopy Integrated Centrifugal Microfluidics Platform

    DEFF Research Database (Denmark)

    Durucan, Onur

    This PhD thesis demonstrates (i) centrifugal microfluidics disc platform integrated with Au capped nanopillar (NP) substrates for surface-enhanced Raman spectroscopy (SERS) based sensing, and (ii) novel sample analysis concepts achieved by synergistical combination of sensing techniques and minia......This PhD thesis demonstrates (i) centrifugal microfluidics disc platform integrated with Au capped nanopillar (NP) substrates for surface-enhanced Raman spectroscopy (SERS) based sensing, and (ii) novel sample analysis concepts achieved by synergistical combination of sensing techniques...... dense array of NP structures. Furthermore, the wicking assisted nanofiltration procedure was accomplished in centrifugal microfluidics platform and as a result additional sample purification was achieved through the centrifugation process. In this way, the Au coated NP substrate was utilized...

  9. Centrifugal potential energy : an astounding renewable energy concept

    Energy Technology Data Exchange (ETDEWEB)

    Oduniyi, I.A. [Aled Conglomerate Nigeria Ltd., Lagos (Nigeria)

    2010-07-01

    A new energy concept known as centrifugal potential energy was discussed. This new energy concept is capable of increasing the pressure, temperature and enthalpy of a fluid, without having to apply work or heat transfer to the fluid. It occurs through a change in the centrifugal potential energy of the flowing fluid in a rotating frame of reference or a centrifugal force field, where work is performed internally by the centrifugal weight of the fluid. This energy concept has resulted in new energy equations, such as the Rotational Frame Bernoulli's Equation for liquids and the Rotational Frame Steady-Flow Energy Equation for gases. Applications of these equations have been incorporated into the design of centrifugal field pumps and compressors. Rather than compressing a fluid with a physical load transfer, these devices can compress a fluid via the effect of centrifugal force applied to the object. A large amount of energy is therefore produced when this high pressure compressed working fluid expands in a turbine. When water is used as the working fluid, it could reach renewable energy densities in the range of 25-100 kJ/kg of water. When atmospheric air is used, it could reach energy densities in the range of 500-1,500 kJ/kg of air.

  10. Rotor for a pyrolysis centrifuge reactor

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a rotor for a pyrolysis centrifuge reactor, said rotor comprising a rotor body having a longitudinal centre axis, and at least one pivotally mounted blade being adapted to pivot around a pivot axis under rotation of the rotor body around the longitudinal centre axis....... Moreover, the present invention relates to a pyrolysis centrifuge reactor applying such a rotor....

  11. Enrichment technology. Dependable vendor of gas centrifuges

    International Nuclear Information System (INIS)

    Anon.

    2011-01-01

    Enrichment Technology is an innovative, high-tech company that develops, manufactures and installs gas centrifuges for enriching uranium. In addition, Enrichment Technology designs enrichment plants that use gas centrifuge technology. This technology offers the most efficient and cost-effective method for enriching uranium yet: high-performance, safe technology that dominates the market with a global share of 45 percent. A determining factor in Enrichment Technology's success is its mission: supplying its customers with safe, reliable technology. Production of the centrifuges requires versatile know-how and collaboration between different departments as well as interdisciplinary teams at the various sites. More than 2000 operators at 8 sites in 5 countries contribute their individual knowledge and personal skills in order to produce this exceptional technology. The head office is in Beaconsfield near London and the operational headquarters are in Almelo in the Netherlands. There are other sites in Germany (Juelich und Gronau), Great Britain (Capenhurst) as well as project sites in the USA and France. Capenhurst is where experienced engineers design new enrichment plants and organise their construction. Centrifuge components are manufactured in Almelo and Juelich, while the pipework needed to connect up the centrifuges is produced at the site in Gronau. In Juelich, highly qualified scientists in interdisciplinary teams are continuously researching ways of improving the current centrifuges. Communication between specialists in the fields of chemistry, physics and engineering forms the basis for the company's success and the key to extending this leading position in the global enrichment market. (orig.)

  12. The effect of increased centrifugation temperature on the quality of red-blood-cell concentrates of automated whole blood processing.

    Science.gov (United States)

    Weinigel, C; Rummler, S; Barz, D

    2013-10-01

    There are manual and automated methods to separate whole blood (WB) available. The Atreus whole blood processing system is an automated method, which combines centrifugation and expression of components into a single device. A major difference to conventional methods is that centrifugation temperature is not controlled at 22°C. The aim of this study was to examine the influence of increased centrifugation temperatures on the quality of red-blood-cell concentrates (RCC) after active cooling of WB prior to processing. A total of 28 WB were processed: 16 at centrifugation temperatures of up to 28°C (1st protocol) and 12 at 34°C (2nd protocol). RCC quality parameters were tested weekly for 42 days. Red-blood-cell concentrates (RCC) quality complied with the European and German guidelines. Haemolysis was not significantly different throughout storage. Significant statistical differences were detected between both protocols in potassium concentration at the end of storage and in ATP levels at the day of processing. Centrifugation temperatures of up to 34°C are well tolerated by the red blood cells with minimal interference with the RCC quality parameters. © 2013 International Society of Blood Transfusion.

  13. Detection of outliers in gas centrifuge experimental data

    International Nuclear Information System (INIS)

    Andrade, Monica C.V.; Nascimento, Claudio A.O.

    2005-01-01

    Isotope separation in a gas centrifuge is a very complex process. Development and optimization of a gas centrifuge requires experimentation. These data contain experimental errors, and like other experimental data, there may be some gross errors, also known as outliers. The detection of outliers in gas centrifuge experimental data may be quite complicated because there is not enough repetition for precise statistical determination and the physical equations may be applied only on the control of the mass flows. Moreover, the concentrations are poorly predicted by phenomenological models. This paper presents the application of a three-layer feed-forward neural network to the detection of outliers in a very extensive experiment for the analysis of the separation performance of a gas centrifuge. (author)

  14. Towards an optimized flow-sheet for a SANEX demonstration process using centrifugal contactors

    International Nuclear Information System (INIS)

    Magnusson, D.; Christiansen, B.; Glatz, J.P.; Malmbeck, R.; Serrano-Purroy, D.; Modolo, G.; Sorel, C.

    2008-01-01

    The design of an efficient process flow-sheet requires accurate extraction data for the experimental set-up used. Often this data is provided as equilibrium data. Due to the small hold-up volume compared to the flow rate in centrifugal contactors the time for extraction is often too short to reach the equilibrium D-ratios. In this work single stage kinetics experiments have been carried out to investigate the D-ratio dependence of the flow rate and also to compare with equilibrium batch experiments for CyMe 4 - BTBP. The first centrifuge experiment was run with spiked solutions while in the second a genuine actinide/lanthanide fraction from a TODGA process was used. Three different flow rates were tested with each set-up. The results show that even with low flow rates, around 8% of the equilibrium D-ratio (Am) was reached for the extraction in the spiked test and around 16% in the hot test (the difference is due to the size of the centrifuges). The general conclusion is that the development of a process flow sheet needs investigation of the kinetic behaviour in the actual equipment used. (authors)

  15. Numerical analysis of flow in ultra micro centrifugal compressor -influence of meridional configuration

    Science.gov (United States)

    Kaneko, Masanao; Tsujita, Hoshio; Hirano, Toshiyuki

    2013-04-01

    A single stage ultra micro centrifugal compressor constituting ultra micro gas turbine is required to operate at high rotational speed in order to achieve the pressure ratio which establishes the gas turbine cycle. As a consequence, the aerodynamic losses can be increased by the interaction of a shock wave with the boundary layer on the blade surface. Moreover, the centrifugal force which exceeds the allowable stress of the impeller material can act on the root of blades. On the other hand, the restrictions of processing technology for the downsizing of impeller not only relatively enlarge the size of tip clearance but also make it difficult to shape the impeller with the three-dimensional blade. Therefore, it is important to establish the design technology for the impeller with the two-dimensional blade which possesses the sufficient aerodynamic performance and enough strength to bear the centrifugal force caused by the high rotational speed. In this study, the flow in two types of impeller with the two-dimensional blade which have different meridional configuration was analyzed numerically. The computed results clarified the influence of the meridional configuration on the loss generations in the impeller passage.

  16. Centrifuge modelling - migration of radionuclides from engineered trenches

    International Nuclear Information System (INIS)

    Dean, E.T.R.; Schofield, A.N.

    1991-12-01

    This report provides an overview of some centrifuge small-scale physical model tests and 1g experimental and theoretical work relating to the sub-surface migration of a model pollutant (sodium chloride) from a notional prototype surface landfill of width 25 metres and depth 3 metres cut into a 20 metre deep layer of nominally uniform soil overlying a more permeable base layer. An introduction is given to the application of geotechnical centrifuge modelling techniques to pollutant migration studies. Experiments performed at 1/100th scale using the Cambridge 10 metre diameter Geotechnical Beam Centrifuge simulating transport through silt over prototype time periods of around 35 years, are summarised. Comparisons of data with calculations using early versions of the POLLUTE and MIGRATE computer codes are presented. An experiment at 1/400th scale using the new Cambridge Geotechnical Drum Centrifuge, involving transport through clay over a prototype time period of around 1000 years, is described. Potential future uses of centrifuge modelling techniques to simulate long-term migration through more complex hydrological environments are also discussed. (author)

  17. Effect of science laboratory centrifuge of space station environment

    Science.gov (United States)

    Searby, Nancy

    1990-01-01

    It is argued that it is essential to have a centrifuge operating during manned space station operations. Background information and a rationale for the research centrifuge are given. It is argued that we must provide a controlled acceleration environment for comparison with microgravity studies. The lack of control groups in previous studies throws into question whether the obseved effects were the result of microgravity or not. The centrifuge could be used to provide a 1-g environment to supply specimens free of launch effects for long-term studies. With the centrifuge, the specimens could be immediately transferred to microgravity without undergoing gradual acclimation. Also, the effects of artificial gravity on humans could be investigated. It is also argued that the presence of the centrifuge on the space station will not cause undo vibrations or other disturbing effects.

  18. Plutonium recovery from incinerator ash and centrifuge sludge by peroxide fusion

    International Nuclear Information System (INIS)

    Partridge, J.A.; Wheelwright, E.J.

    1975-05-01

    A technique was demonstrated for solubilizing the plutonium contained in incinerator ash and in other waste solids (such as solids accumulated by centrifugation after solvent extraction contacts in the plutonium reclamation facility at Hanford). A sodium hydroxide--sodium peroxide fusion is performed on the Pu-containing solids. The cooled melt is then dissolved in dilute nitric acid. Mild steel cans were used as ''single use'' crucibles for the fusions. Both the can and the cooled melt are dissolved in nitric acid. Fusion tests were conducted on three different cans of incinerator ash and on one can of centrifuge sludge. The series of tests demonstrated that a caustic-peroxide fusion treatment can yield 95 percent or greater recovery of plutonium from these waste solids. In most cases, quantitative recovery of the plutonium can probably be achieved by recycling the residual solids obtained in aqueous dissolution of the cooled fusion mixture. Tests with some of the incinerator ash and with the centrifuge sludge resulted in gelatinous precipitates which were difficult to separate from the nitric acid dissolver solutions. These gelatinous precipitates present what is probably the major problem to be overcome in the use of this Pu recovery method. Techniques need to be examined for making these residual solids less difficult to separate from the dissolver solution. (U.S.)

  19. Experimental and numerical investigation of centrifugal pumps with asymmetric inflow conditions

    Science.gov (United States)

    Mittag, Sten; Gabi, Martin

    2015-11-01

    Most of the times pumps operate off best point states. Reasons are changes of operating conditions, modifications, pollution and wearout or erosion. As consequences non-rotational symmetric flows, transient operational conditions, increased risk of cavitation, decrease of efficiency and unpredictable wearout can appear. Especially construction components of centrifugal pumps, in particular intake elbows, contribute to this matter. Intake elbows causes additional losses and secondary flows, hence non-rotational velocity distributions as intake profile to the centrifugal pump. As a result the impeller vanes experience permanent changes of the intake flow angle and with it transient flow conditions in the blade channels. This paper presents the first results of a project, experimentally and numerically investigating the consequences of non-rotational inflow to leading edge flow conditions of a centrifugal pump. Therefore two pumpintake- elbow systems are compared, by only altering the intake elbow geometry: a common single bended 90° elbow and a numerically optimized elbow (improved regarding rotational symmetric inflow conditions and friction coefficient). The experiments are carried out, using time resolved stereoscopic PIV on a full acrylic pump with refractions index matched (RIM) working fluid. This allows transient investigations of the flow field simultaneously for all blade leading edges. Additional CFD results are validated and used to further support the investigation i.e. for comparing an analog pump system with ideal inflow conditions.

  20. Centrifugal microfluidic platforms: advanced unit operations and applications.

    Science.gov (United States)

    Strohmeier, O; Keller, M; Schwemmer, F; Zehnle, S; Mark, D; von Stetten, F; Zengerle, R; Paust, N

    2015-10-07

    Centrifugal microfluidics has evolved into a mature technology. Several major diagnostic companies either have products on the market or are currently evaluating centrifugal microfluidics for product development. The fields of application are widespread and include clinical chemistry, immunodiagnostics and protein analysis, cell handling, molecular diagnostics, as well as food, water, and soil analysis. Nevertheless, new fluidic functions and applications that expand the possibilities of centrifugal microfluidics are being introduced at a high pace. In this review, we first present an up-to-date comprehensive overview of centrifugal microfluidic unit operations. Then, we introduce the term "process chain" to review how these unit operations can be combined for the automation of laboratory workflows. Such aggregation of basic functionalities enables efficient fluidic design at a higher level of integration. Furthermore, we analyze how novel, ground-breaking unit operations may foster the integration of more complex applications. Among these are the storage of pneumatic energy to realize complex switching sequences or to pump liquids radially inward, as well as the complete pre-storage and release of reagents. In this context, centrifugal microfluidics provides major advantages over other microfluidic actuation principles: the pulse-free inertial liquid propulsion provided by centrifugal microfluidics allows for closed fluidic systems that are free of any interfaces to external pumps. Processed volumes are easily scalable from nanoliters to milliliters. Volume forces can be adjusted by rotation and thus, even for very small volumes, surface forces may easily be overcome in the centrifugal gravity field which enables the efficient separation of nanoliter volumes from channels, chambers or sensor matrixes as well as the removal of any disturbing bubbles. In summary, centrifugal microfluidics takes advantage of a comprehensive set of fluidic unit operations such as

  1. Microcomputer-based instrument for the detection and analysis of precession motion in a gas centrifuge machine

    International Nuclear Information System (INIS)

    Paulus, S.S.

    1986-03-01

    The Centrifuge Precession Analyzer (CPA) is a microcomputer-based instrument which detects precession motion in a gas centrifuge machine and calculates the amplitude and frequency of precession. The CPA consists of a printed circuit board which contains signal-conditioning circuitry and a 24-bit counter and an INTEL iSBC 80-/24 single-board computer. Precession motion is detected by monitoring a signal generated by a variable reluctance pick-up coil in the top of the centrifuge machine. This signal is called a Fidler signal. The initial Fidler signal triggers a counter which is clocked by a high-precision, 20.000000-MHz, temperature-controlled, crystal oscillator. The contents of the counter are read by the computer, and the counter reset after every ten Fidler signals. The speed of the centrifuge machine and the amplitude and frequency of precession are calculated, and the results are displayed on a liquid crystal display on the front panel of the CPA. The thesis contains results from data generated by a Fidler signal simulator and data taken when the centrifuge was operated under three test conditions: (1) nitrogen gas during drive-up, steady state, and drive-down, (2) xenon gas during slip test, steady state, and the addition of gas, and (3) no gas during steady state. The qualitative results were consistent with experience with centrifuge machines UF 6 in that the amplitude of precession increased and the frequency of precession decreased during drive-up, drive-down and the slip check. The magnitude of the amplitude and frequency of precession were proportional to the molecular weight of the gases in steady state

  2. Forces on Centrifugal Pump Impellers

    OpenAIRE

    Jery, Belgacem; Brennen, Christopher E.; Caughey, Thomas K.; Acosta, Allan

    1985-01-01

    Forces are exerted on a centrifugal pump impeller, due to the asymmetry of the flow caused by the volute of diffuser, and to the motion of the center of the impeller whenever the shaft whirls. Recent work in the measurement of these forces as a function of the whirl speed to shaft speed ratio, and the influence of the volute, is reviewed. These forces may be decomposed into a steady force, a static stiffness matrix, a damping matrix and an inertia matrix. It is shown that for centrifugal p...

  3. Effect of Bioactive Materials Modified with Chondroitin Sulfate on Human MSC =

    Science.gov (United States)

    De La Torre Torres, Jessica Elizabeth

    In this project chondroitin sulfate (CS) and growth factors were studied for their effect on hMSC in biomaterials. First, the effect of these biomolecules was tested in solution. Then, two kinds of biomaterials were created: bioactive surfaces for enhancing bioactivity of implantable devices and bioactive hydrogels which can be used as 3D scaffolds for cell encapsulation and delivery. A pro-survival effect of the growth factors studied in this project (epidermal growth factor, vascular endothelial growth factor and fibroblast growth factor) was not observed when tested in solution, therefore the project further focused on CS effect only. Interestingly, CS did not affect cell growth in media containing serum, while inducing cell detachment from substrate in serum free conditions. For the bioactive surfaces construction, CS was grafted to either an amine-rich plasmapolymerized coating created on polyethylene terephthalate (PET) films (further referred as LP) or to commercial cell culture plates functionalized with amino groups. The bioactive surfaces were characterized by different techniques such as contact angle, atomic force microscopy, Orange II dye and Toluidine Blue O dye colorimetric assays (for amino group and CS quantification respectively) and finally, cell culture experiments (adhesion, growth and survival). Results confirmed the presence of CS grafted on both substrates. Commercial amine plates grafted almost five times more CS compared to LP. This rendered the surface antifouling for proteins and cells as confirmed by protein adsorption and cell culture assays. Cell culture assays on bioactive surfaces based on LP demonstrated improved cell adhesion and growth when compared to tissue culture plates or bare PET films in serum containing conditions. Chitosan based hydrogels containing CS at a concentration of 500 mug/ml resulted in a cohesive hydrogel which supported hMSC viability up to 7 days. However increasing CS concentration to high level such as

  4. Centrifuge modelling of contaminant transport processes

    OpenAIRE

    Culligan, P. J.; Savvidou, C.; Barry, D. A.

    1996-01-01

    Over the past decade, research workers have started to investigate problems of subsurface contaminant transport through physical modelling on a geotechnical centrifuge. A major advantage of this apparatus is its ability to model complex natural systems in a controlled laboratory environment In this paper, we discusses the principles and scaling laws related to the centrifugal modelling of contaminant transport, and presents four examples of recent work that has bee...

  5. Flow induced vibrations in gas tube assembly of centrifuge

    International Nuclear Information System (INIS)

    Alam, M.; Atta, M.A.; Mirza, J.A.; Khan, A.Q.

    1986-01-01

    A centrifuge essentially consists of a rotor rotating at very high speed. Gas tube assembly, located at the center of the rotor, is used to introduce feed gas into the rotor and remove product and waste streams from it. The gas tube assembly is thus a static component, the product and waste scoops of which are lying in the high pressure region of a fluid rotating at very high speed. This can cause flow induced vibrations in the gas tube assembly. Such vibrations affect not only the mechanical stability of the gas tube assembly but may also reduce the separative power of the centrifuge. In a cascade, if some of the centrifuges have gas tube vibration, then cascade performance will be affected. A theoretical analysis of the effect of waste tube vibrations on product and waste flow rates and pressures in the centrifuge is presented. A simple stage consisting of two centrifuges, in which one has tube vibration, is considered for this purpose. The results are compared with experiment. It is shown that waste tube vibration generates oscillations in waste and product flow rates that are observable outside the centrifuge. (author)

  6. Direct Monte-Carlo Siumulations In a Gas Centrifuge

    National Research Council Canada - National Science Library

    Roblin, Philippe

    2000-01-01

    The study is related to the centrifugation process for isotope separation. In a gas centrifuge, the major part of the rotating gas is modeled by fluid equations with this gas flow described by suitable Navier-Stokes...

  7. Removal of bacteria from boar ejaculates by Single Layer Centrifugation can reduce the use of antibiotics in semen extenders.

    Science.gov (United States)

    Morrell, J M; Wallgren, M

    2011-01-01

    There is considerable interest world-wide in reducing the use of antibiotics to stem the development of antibiotic-resistant strains of bacteria. An alternative to the routine addition of antibiotics to semen extenders in livestock breeding would be to separate the spermatozoa from bacterial contaminants in the semen immediately after collection. The present study was designed to determine whether such separation was possible by Single Layer Centrifugation (SLC) using the colloid Androcoll™-P. The results showed that complete removal (6 out of 10 samples), or considerable reduction of bacterial contaminants (4 out of 10 samples) was possible with this method. The type of bacteria and/or the length of time between collection and SLC-processing affected the removal of bacteria, with motile flagellated bacteria being more likely to be present after SLC than non-flagellated bacteria. Although further studies are necessary, these preliminary results suggest that the use of SLC when processing boar semen for AI doses might enable antibiotic usage in semen extenders to be reduced. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. In vivo MR detection of fluorine-labeled human MSC using the bSSFP sequence

    Directory of Open Access Journals (Sweden)

    Ribot EJ

    2014-04-01

    Full Text Available Emeline J Ribot,1 Jeffrey M Gaudet,1,2 Yuhua Chen,1 Kyle M Gilbert,1 Paula J Foster1,2 1Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada; 2Department of Medical Biophysics, University of Western Ontario, London, ON, Canada Abstract: Mesenchymal stem cells (MSC are used to restore deteriorated cell environments. There is a need to specifically track these cells following transplantation in order to evaluate different methods of implantation, to follow their migration within the body, and to quantify their accumulation at the target. Cellular magnetic resonance imaging (MRI using fluorine-based nanoemulsions is a great means to detect these transplanted cells in vivo because of the high specificity for fluorine detection and the capability for precise quantification. This technique, however, has low sensitivity, necessitating improvement in MR sequences. To counteract this issue, the balanced steady-state free precession (bSSFP imaging sequence can be of great interest due to the high signal-to-noise ratio (SNR. Furthermore, it can be applied to obtain 3D images within short acquisition times. In this paper, bSSFP provided accurate quantification of samples of the perfluorocarbon Cell Sense-labeled cells in vitro. Cell Sense was internalized by human MSC (hMSC without adverse alterations in cell viability or differentiation into adipocytes/osteocytes. The bSSFP sequence was applied in vivo to track and quantify the signals from both Cell Sense-labeled and iron-labeled hMSC after intramuscular implantation. The fluorine signal was observed to decrease faster and more significantly than the volume of iron-associated voids, which points to the advantage of quantifying the fluorine signal and the complexity of quantifying signal loss due to iron. Keywords: bSSFP, fluorine MRI, mesenchymal stem cell, mouse, cell tracking

  9. Gas centrifuge uranium enrichment programme in the United States of America

    International Nuclear Information System (INIS)

    Gestson, D.K.

    1983-01-01

    The technology of uranium enrichment using the gas centrifuge is fully proven as a result of over twenty years of research. The high performance of the centrifuge has been confirmed, and its reliability established, through detailed evaluation of a series of centrifuge designs. The baseline centrifuge for the Gas Centrifuge Enrichment Plant (GCEP) is now in commercial production by three qualified manufacturers. It will be ready for installation in GCEP on schedule. The GCEP construction is also on schedule, with two process buildings expected to start operation in 1988 and 1989. Development and demonstration of the Set IV advanced gas centrifuge is under way and it is expected to be ready for installation in Process Building 3 in early 1989. (author)

  10. The therapeutic effects of MSc1 nanocomplex, synthesized by nanochelating technology, on experimental autoimmune encephalomyelitic C57/BL6 mice

    Directory of Open Access Journals (Sweden)

    Fakharzadeh S

    2014-08-01

    Full Text Available Saideh Fakharzadeh,1 Mohammad Ali Sahraian,2 Maryam Hafizi,1 Somayeh Kalanaky,1 Zahra Masoumi,1 Mehdi Mahdavi,1 Nasser Kamalian,3 Alireza Minagar,4 Mohammad Hassan Nazaran1 1Department of Research and Development, Sodour Ahrar Shargh Company, Tehran, Iran; 2MS Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran; 3Department of Pathology, Medical School of Tehran University of Medical Sciences, Tehran, Iran; 4Department of Neurology, LSU Health Sciences Centre, Shreveport, LA, USA Purpose: Currently approved therapies for multiple sclerosis (MS at best only slow down its progression. Therefore, it is necessary to utilize novel technologies in order to synthesize smart multifunctional structures. In the present study, for the first time we evaluated the therapeutic potential of MSc1 nanocomplex, which was designed based on novel nanochelating technology. Materials and methods: MSc1 cell-protection capacity, with and without iron bond, was evaluated against hydrogen peroxide (H2O2-induced oxidative stress in cultured rat pheochromocytoma-12 cells. The ability of MSc1 to maintain iron bond at pH ranges of 1–7 was evaluated. Nanocomplex toxicity was examined by estimating the intraperitoneal median lethal dose (LD50. Experimental autoimmune encephalomyelitic mice were injected with MSc1 14 days after disease induction, when the clinical symptoms appeared. The clinical score, body weight, and disease-induced mortality were monitored until day 54. In the end, after collecting blood samples for assessing hemoglobin and red blood cell count, the brains and livers of the mice were isolated for hematoxylin and eosin staining and analysis of iron content, respectively. Results: The results showed that MSc1 prevented H2O2-induced cell death even after binding with iron, and it preserved its bond with iron constant at pH ranges 1–7. The nanocomplex intraperitoneal LD50 was 1,776.59 mg/kg. MSc1 prompted therapeutic

  11. Numerical simulation of the unsteady progress in centrifuge

    International Nuclear Information System (INIS)

    Wei Chunlin; Zeng Shi

    2006-01-01

    Unsteady flow equations for the centrifuge are solved on a staggered grid by a finite volume method. The transient process that the axial flow in the centrifuge is established under a steady thermal driving. It can be concluded that the influence which causes the perturbing fluid is different at the beginning and the end of the processing. The flow is caused by the imbalance of temperature which turns to be caused by the imbalance of pressure. The results show that the numerical simulation is effective at the unsteady fluid in a centrifuge. (authors)

  12. High Efficiency Centrifugal Compressor for Rotorcraft Applications

    Science.gov (United States)

    Medic, Gorazd; Sharma, Om P.; Jongwook, Joo; Hardin, Larry W.; McCormick, Duane C.; Cousins, William T.; Lurie, Elizabeth A.; Shabbir, Aamir; Holley, Brian M.; Van Slooten, Paul R.

    2017-01-01

    A centrifugal compressor research effort conducted by United Technologies Research Center under NASA Research Announcement NNC08CB03C is documented. The objectives were to identify key technical barriers to advancing the aerodynamic performance of high-efficiency, high work factor, compact centrifugal compressor aft-stages for turboshaft engines; to acquire measurements needed to overcome the technical barriers and inform future designs; to design, fabricate, and test a new research compressor in which to acquire the requisite flow field data. A new High-Efficiency Centrifugal Compressor stage -- splittered impeller, splittered diffuser, 90 degree bend, and exit guide vanes -- with aerodynamically aggressive performance and configuration (compactness) goals were designed, fabricated, and subquently tested at the NASA Glenn Research Center.

  13. 85,000-GPM, single-stage, single-suction LMFBR intermediate centrifugal pump

    International Nuclear Information System (INIS)

    Fair, C.E.; Cook, M.E.; Huber, K.A.; Rohde, R.

    1983-01-01

    The mechanical and hydraulic design features of the 85,000-gpm, single-stage, single-suction pump test article, which is designed to circulate liquid-sodium coolant in the intermediate heat-transport system of a Large-Scale Liquid Metal Fast Breeder Reactor (LS-LMFBR), are described. The design and analytical considerations used to satisfy the pump performance and operability requirements are presented. The validation of pump hydraulic performance using a hydraulic scale-model pump is discussed, as is the featute test for the mechanical-shaft seal system

  14. Separative properties of counter-current beams type centrifuge, (2)

    International Nuclear Information System (INIS)

    Todo, Fukuzo

    1975-01-01

    One-time through scheme is studied, which would produce the highest overall centrifuge efficiency among the three different flow schemes of enriching, stripping and one-time through. If the ''optimum concentration method'' is applied to the one-time through centrifuge, the machine will be able to obtain a very high efficiency at small gas flow rates. A proposed arrangement of centrifuges for this method is shown. The efficiency of this method will be more than 15--20% higher than obtainable with enriching scheme. When the radial gas flow rate near the end caps in the rotor is increased to about 10% of the total gas feed rate, the efficiency was found to decrease by only 1%. The efficiency appears to be almost independent of small amounts of refluxing gas flow. Since a separation method having a high efficiency at small gas flow rates is required for large-scale gas centrifuge plants, the one-time through centrifuge is promising, provided the optimum concentration method is adopted. (auth.)

  15. Evaluation of a reduced centrifugation time and higher centrifugal force on various general chemistry and immunochemistry analytes in plasma and serum.

    Science.gov (United States)

    Møller, Mette F; Søndergaard, Tove R; Kristensen, Helle T; Münster, Anna-Marie B

    2017-09-01

    Background Centrifugation of blood samples is an essential preanalytical step in the clinical biochemistry laboratory. Centrifugation settings are often altered to optimize sample flow and turnaround time. Few studies have addressed the effect of altering centrifugation settings on analytical quality, and almost all studies have been done using collection tubes with gel separator. Methods In this study, we compared a centrifugation time of 5 min at 3000 ×  g to a standard protocol of 10 min at 2200 ×  g. Nine selected general chemistry and immunochemistry analytes and interference indices were studied in lithium heparin plasma tubes and serum tubes without gel separator. Results were evaluated using mean bias, difference plots and coefficient of variation, compared with maximum allowable bias and coefficient of variation used in laboratory routine quality control. Results For all analytes except lactate dehydrogenase, the results were within the predefined acceptance criteria, indicating that the analytical quality was not compromised. Lactate dehydrogenase showed higher values after centrifugation for 5 min at 3000 ×  g, mean bias was 6.3 ± 2.2% and the coefficient of variation was 5%. Conclusions We found that a centrifugation protocol of 5 min at 3000 ×  g can be used for the general chemistry and immunochemistry analytes studied, with the possible exception of lactate dehydrogenase, which requires further assessment.

  16. Modelling of hydrothermal characteristics of centrifugal nozzles

    International Nuclear Information System (INIS)

    Yarkho, A.A.; Omelchenko, M.P.; Borshchev, V.A.

    1990-01-01

    Presented for the first time is a method of recalculating the hydrothermal characteristics of centrifugal nozzles obtained in laboratory conditions for full-scale nozzles. From the experimental hydrothermal characteristics of nozzles observed in the laboratory it is allowed to calculate the hydrothermal characteristics of any other centrifugal nozzle whose diameter and dimensionless geometric characteristic are known

  17. Astronaut Gordon Cooper in centrifuge for tests

    Science.gov (United States)

    1963-01-01

    Astronaut L. Gordon Cooper, prime pilot for the Mercury-Atlas 9 mission, is strapped into the gondola while undergoing tests in the centrifuge at the Naval Air Development Center, Johnsville, Pennsylvania. The centrifuge is used to investigate by simulation the pilot's capability to control the vehicle during the actual flight in its booster and reentry profile.

  18. Physical simulations using centrifuge techniques

    International Nuclear Information System (INIS)

    Sutherland, H.J.

    1981-01-01

    Centrifuge techniques offer a technique for doing physical simulations of the long-term mechanical response of deep ocean sediment to the emplacement of waste canisters and to the temperature gradients generated by them. Preliminary investigations of the scaling laws for pertinent phenomena indicate that the time scaling will be consistent among them and equal to the scaling factor squared. This result implies that this technique will permit accelerated-life-testing of proposed configurations; i.e, long-term studies may be done in relatively short times. Presently, existing centrifuges are being modified to permit scale model testing. This testing will start next year

  19. Relativistic centrifugal instability

    Science.gov (United States)

    Gourgouliatos, Konstantinos N.; Komissarov, Serguei S.

    2018-03-01

    Near the central engine, many astrophysical jets are expected to rotate about their axis. Further out they are expected to go through the processes of reconfinement and recollimation. In both these cases, the flow streams along a concave surface and hence, it is subject to the centrifugal force. It is well known that such flows may experience the centrifugal instability (CFI), to which there are many laboratory examples. The recent computer simulations of relativistic jets from active galactic nuclei undergoing the process of reconfinement show that in such jets CFI may dominate over the Kelvin-Helmholtz instability associated with velocity shear (Gourgouliatos & Komissarov). In this letter, we generalize the Rayleigh criterion for CFI in rotating fluids to relativistic flows using a heuristic analysis. We also present the results of computer simulations which support our analytic criterion for the case of an interface separating two uniformly rotating cylindrical flows. We discuss the difference between CFI and the Rayleigh-Taylor instability in flows with curved streamlines.

  20. Considerations on safeguards approach for small centrifuge enrichment facilities

    International Nuclear Information System (INIS)

    Vicens, Hugo E.; Marzo, Marco A.; Nunes, Vitorio E.

    2004-01-01

    The safeguards' objectives for enrichment facilities encompass the detection of the diversion of declared nuclear material and of facility misuse. The safeguard's approach presently applied for commercial centrifuge enrichment facilities is based on the Hexa partite Project and seems not to be directly applicable to cases of small plants. Since ABACC started its operation one of the main problems faced was the application of safeguards to small centrifuge enrichment plants for testing centrifuges in cascade mode or for small LEU production. These plants consist of a few fully independent cascades, does not operate in a routine basis and panels prevent visual access to the centrifuges and their surroundings for preserving sensitive information. For such plants misuse scenarios seems to dominate, particularly those associated with feeding the plant with undeclared LEU. This paper presents a concise analysis of misuse strategies in small centrifuge facility and alternative safeguard's approach, describing the main control elements to be applied. The particularities arising from the existence of panels or boxes covering the centrifuges are specifically addressed. Two alternatives approaches based on the application of a transitory perimeter control to increase the effectiveness of unannounced inspection and on the application of permanent perimeter control are presented. (author)

  1. Design and construction of a two-stage centrifugal pump | Nordiana ...

    African Journals Online (AJOL)

    Centrifugal pumps are widely used in moving liquids from one location to another in homes, offices and industries. Due to the ever increasing demand for centrifugal pumps it became necessary to design and construction of a two-stage centrifugal pump. The pump consisted of an electric motor, a shaft, two rotating impellers ...

  2. Centrifugal Blower for Personal Air Ventilation System (PAVS) - Phase 1

    Science.gov (United States)

    2015-02-01

    3  FIGURE 5: PHOTO & PERFORMANCE PLOT OF EXISTING CENTRIFUGAL COMPRESSOR ...aerodynamically similar to an existing centrifugal compressor pictured in Figure 5. The performance plot of this compressor demonstrates a high...blade tip diameter at impeller exit Figure 5: Photo & Performance plot of existing centrifugal compressor 70% 75% 65% 60%   6

  3. DEM simulation of granular flows in a centrifugal acceleration field

    Science.gov (United States)

    Cabrera, Miguel Angel; Peng, Chong; Wu, Wei

    2017-04-01

    The main purpose of mass-flow experimental models is abstracting distinctive features of natural granular flows, and allow its systematic study in the laboratory. In this process, particle size, space, time, and stress scales must be considered for the proper representation of specific phenomena [5]. One of the most challenging tasks in small scale models, is matching the range of stresses and strains among the particle and fluid media observed in a field event. Centrifuge modelling offers an alternative to upscale all gravity-driven processes, and it has been recently employed in the simulation of granular flows [1, 2, 3, 6, 7]. Centrifuge scaling principles are presented in Ref. [4], collecting a wide spectrum of static and dynamic models. However, for the case of kinematic processes, the non-uniformity of the centrifugal acceleration field plays a major role (i.e., Coriolis and inertial effects). In this work, we discuss a general formulation for the centrifugal acceleration field, implemented in a discrete element model framework (DEM), and validated with centrifuge experimental results. Conventional DEM simulations relate the volumetric forces as a function of the gravitational force Gp = mpg. However, in the local coordinate system of a rotating centrifuge model, the cylindrical centrifugal acceleration field needs to be included. In this rotating system, the centrifugal acceleration of a particle depends on the rotating speed of the centrifuge, as well as the position and speed of the particle in the rotating model. Therefore, we obtain the formulation of centrifugal acceleration field by coordinate transformation. The numerical model is validated with a series of centrifuge experiments of monodispersed glass beads, flowing down an inclined plane at different acceleration levels and slope angles. Further discussion leads to the numerical parameterization necessary for simulating equivalent granular flows under an augmented acceleration field. The premise of

  4. Effect of mesenchymal stromal cells (MSC) on chronic visceral hypersensitivity in a radio-induced colonic ulceration model in the rat

    International Nuclear Information System (INIS)

    Durand, Christelle

    2014-01-01

    Patients who undergo pelvic radiotherapy may develop significant incidence of undesirable chronic gastrointestinal complications resulting from radiation-induced damages around the tumour. Chronic visceral pain is one of the radiation-induced side effects that greatly affects the quality of life of 'cancer survivors'. The lack of effective analgesic treatment highlights the importance of novel and effective therapeutic strategies. In our laboratory, mesenchymal stromal cell (MSC) based approach showed beneficial immunomodulatory and regenerative effects in a rat model of irreversible radiationinduced colonic ulcers. The goal of my work was to assess the relevance of this model to study radiation-induced visceral persistent hypersensitivity and its modulation by MSC treatment. We first demonstrated that this model is associated with long-lasting visceral hypersensitivity and central neuronal sensitization. In this context we showed then that mast cells (MC) are involved in the mechanism of peripheral sensitization. Moreover, we suggested the implication of the neuro-mediator NO . in the pathophysiology of persistent radiation-induced visceral hypersensitivity. We also suggested that MSC treatment reversed radiation-induced hypersensitivity by a mechanism that in part may involve the modulation of MC activation and/or the decrease in the number of MC and nerve fiber interactions. In addition, MSC treatment reduced the percentage of nitrinergic neurons, increased after irradiation, and restored colonic muscular contractibility. Such processes may promote the therapeutic benefit of MSC observed in our study. In conclusion, this work provided new insights on the therapeutic benefit of MSC in our study model and a new argument in favour of their use in a future clinical trial to cure abdomino-pelvic radiotherapy side effects. (author) [fr

  5. Microfluidic size separation of cells and particles using a swinging bucket centrifuge.

    Science.gov (United States)

    Yeo, Joo Chuan; Wang, Zhiping; Lim, Chwee Teck

    2015-09-01

    Biomolecular separation is crucial for downstream analysis. Separation technique mainly relies on centrifugal sedimentation. However, minuscule sample volume separation and extraction is difficult with conventional centrifuge. Furthermore, conventional centrifuge requires density gradient centrifugation which is laborious and time-consuming. To overcome this challenge, we present a novel size-selective bioparticles separation microfluidic chip on a swinging bucket minifuge. Size separation is achieved using passive pressure driven centrifugal fluid flows coupled with centrifugal force acting on the particles within the microfluidic chip. By adopting centrifugal microfluidics on a swinging bucket rotor, we achieved over 95% efficiency in separating mixed 20 μm and 2 μm colloidal dispersions from its liquid medium. Furthermore, by manipulating the hydrodynamic resistance, we performed size separation of mixed microbeads, achieving size efficiency of up to 90%. To further validate our device utility, we loaded spiked whole blood with MCF-7 cells into our microfluidic device and subjected it to centrifugal force for a mere duration of 10 s, thereby achieving a separation efficiency of over 75%. Overall, our centrifugal microfluidic device enables extremely rapid and label-free enrichment of different sized cells and particles with high efficiency.

  6. PARAMETRIC DIAGNOSTICS OF THE CENTRIFUGAL SUPERCHARGER'S TECHNICAL CONDITION DURING OPERATION

    Directory of Open Access Journals (Sweden)

    Regina A. Khuramshina

    2017-01-01

    Full Text Available Abstract. Objectives The main aim is to develop a mathematical model of a centrifugal compressor and carry out a parametric diagnostics of a centrifugal supercharger's technical condition during operation. Methods  A model is proposed for calculating the thermodynamic properties of natural gas, reducing the parameters of a centrifugal compressor to the initial conditions and to the rotation frequency, as well as the integral indicators of the supercharger's technical state. The technical state of the gas path of the centrifugal supercharger of the compressor unit is determined by the parametric diagnostic method. Results  The software implementation of the mathematical model of centrifugal compressor is carried out using a DVIGwT PC. The analysis of calculations indicates that the model is appropriate, with the error being due to taking into account the properties of iso-butane and i-hexane, in contrast with the VNIIGAZ technique. The evaluation studies of a centrifugal compressor's state are indicative of the presence or absence of its defects. Conclusion  Among a number of the diagnostic methods for evaluating a centrifugal supercharger, the most effective is vibrodiagnostics. However, the search for malfunctions and nascent defects in the flowing part of the centrifugal compressor cannot be limited only to vibrodiagnostic data, which provides about 60% of the reliable information about the state of the gas-air tract. About 20% of the compressor's malfunctions and approximately half of the dangerous modes of the supercharger's flow-through part is detected using thermogasdynamic parametric analysis (parametric diagnostics. The main difficulty of the control over the technical state of the flow-through part of the centrifugal supercharger is in the complication of the quantitative evaluation of the processes taking place in the supercharger, which leads to problems in providing reliable diagnosis during a reasonable period of time.

  7. Intra-osseous injection of donor mesenchymal stem cell (MSC) into the bone marrow in living donor kidney transplantation; a pilot study.

    Science.gov (United States)

    Lee, Hyunah; Park, Jae Berm; Lee, Sanghoon; Baek, Soyoung; Kim, HyunSoo; Kim, Sung Joo

    2013-04-11

    Mesenchymal stem cells (MSCs) are multi-potent non-hematopoietic progenitor cells possessing an immune-regulatory function, with suppression of proliferation of activated lymphocytes. In this study, adult living donor kidney transplantation (LDKT) recipients were given MSCs derived from the donor bone marrow to evaluate the safety and the feasibility of immunological changes related to the intra-osseous injection of MSC into the bone marrow. MSCs were derived from negative HLA cross-match donors. Donor bone marrow was harvested 5 weeks prior to KT. At the time of transplantation, 1 x 106 cell/kg of donor MSC was directly injected into the bone marrow of the recipient's right iliac bone. Patients' clinical outcomes, presence of mixed chimerism by short tandem repeat polymerase chain reaction, analysis of plasma FoxP3 mRNA and cytokine level, and mixed lymphocyte reaction (MLR) were performed. Seven patients enrolled in this study and received donor MSC injections simultaneously with LDKT. The median age of recipients was 36 years (32 ~ 48). The number of HLA mismatches was 3 or less in 5 and more than 3 in 2. No local complications or adverse events such as hypersensitivity occurred during or after the injection of donor MSC. There was no graft failure, but the biopsy-proven acute rejections were observed in 3 recipients during the follow-up period controlled well with steroid pulse therapy (SPT). The last serum creatinine was a median of 1.23 mg/dL (0.83 ~ 2.07). Mixed chimerism was not detected in the peripheral blood of the recipients at 1 and 8 week of post-transplantation. Donor-specific lymphocyte or T cell proliferation and Treg priming responses were observed in some patients. Plasma level of IL-10, a known mediator of MSC-induced immune suppression, increased in the patients with Treg induction. Donor MSC injection into the iliac bone at the time of KT was feasible and safe. A possible correlation was observed between the induction of inhibitory

  8. Cardiac arrhythmias during aerobatic flight and its simulation on a centrifuge.

    Science.gov (United States)

    Zawadzka-Bartczak, Ewelina K; Kopka, Lech H

    2011-06-01

    It is well known that accelerations during centrifuge training and during flight can provoke cardiac arrhythmias. Our study was designed to investigate both the similarities and differences between heart rhythm disturbances during flights and centrifuge tests. There were 40 asymptomatic, healthy pilots who performed two training flights and were also tested in a human centrifuge according to a program of rapid onset rate acceleration (ROR) and of centrifuge simulation of the actual acceleration experienced in flight (Simulation). During the flight and centrifuge tests ECG was monitored with the Holter method. ECG was examined for heart rhythm changes and disturbances. During flights, premature ventricular contractions (PVCs) were found in 25% of the subjects, premature supraventricular contractions (PSVCs) and PVCs with bigeminy in 5%, and pairs of PVCs in 2.5% of subjects. During the centrifuge tests, PVCs were experienced by 45% of the subjects, PSVCs and pairs of PVCs by 7.5%, and PVCs with bigeminy by 2.5%. Sinus bradycardia was observed during flights and centrifuge tests in 7.5% of subjects. Comparative evaluation of electrocardiographic records in military pilots during flights and centrifuge tests demonstrated that: 1) there were no clinically significant arrhythmias recorded; and 2) the frequency and kind of heart rhythm disturbances during aerobatic flight and its simulation on a centrifuge were not identical and did not occur repetitively in the same persons during equal phases of the tests.

  9. Optimization of Power Consumption for Centrifugation Process Based on Attenuation Measurements

    Science.gov (United States)

    Salim, M. S.; Abd Malek, M. F.; Sabri, Naseer; Omar, M. Iqbal bin; Mohamed, Latifah; Juni, K. M.

    2013-04-01

    The main objective of this research is to produce a mathematical model that allows decreasing the electrical power consumption of centrifugation process based on attenuation measurements. The centrifugation time for desired separation efficiency may be measured to determine the power consumed of laboratory centrifuge device. The power consumption is one of several parameters that affect the system reliability and productivity. Attenuation measurements of wave propagated through blood sample during centrifugation process were used indirectly to measure the power consumption of device. A mathematical model for power consumption was derived and used to modify the speed profile of centrifuge controller. The power consumption model derived based on attenuation measurements has successfully save the power consumption of centrifugation process keeping high separation efficiency. 18kW.h monthly for 100 daily time device operation had been saved using the proposed model.

  10. Optimization of Power Consumption for Centrifugation Process Based on Attenuation Measurements

    International Nuclear Information System (INIS)

    Salim, M S; Iqbal bin Omar, M; Malek, M F Abd; Mohamed, Latifah; Sabri, Naseer; Juni, K M

    2013-01-01

    The main objective of this research is to produce a mathematical model that allows decreasing the electrical power consumption of centrifugation process based on attenuation measurements. The centrifugation time for desired separation efficiency may be measured to determine the power consumed of laboratory centrifuge device. The power consumption is one of several parameters that affect the system reliability and productivity. Attenuation measurements of wave propagated through blood sample during centrifugation process were used indirectly to measure the power consumption of device. A mathematical model for power consumption was derived and used to modify the speed profile of centrifuge controller. The power consumption model derived based on attenuation measurements has successfully save the power consumption of centrifugation process keeping high separation efficiency. 18kW.h monthly for 100 daily time device operation had been saved using the proposed model.

  11. Probing molecular potentials with an optical centrifuge

    Science.gov (United States)

    Milner, A. A.; Korobenko, A.; Hepburn, J. W.; Milner, V.

    2017-09-01

    We use an optical centrifuge to excite coherent rotational wave packets in N2O, OCS, and CS2 molecules with rotational quantum numbers reaching up to J ≈465 , 690, and 1186, respectively. Time-resolved rotational spectroscopy at such ultra-high levels of rotational excitation can be used as a sensitive tool to probe the molecular potential energy surface at internuclear distances far from their equilibrium values. Significant bond stretching in the centrifuged molecules results in the growing period of the rotational revivals, which are experimentally detected using coherent Raman scattering. We measure the revival period as a function of the centrifuge-induced rotational frequency and compare it with the numerical calculations based on the known Morse-cosine potentials.

  12. Rotating stall simulation for axial and centrifugal compressors

    Science.gov (United States)

    Halawa, Taher; Gadala, Mohamed S.

    2017-05-01

    This study presents a numerical simulation of the rotating stall phenomenon in axial and centrifugal compressors with detailed descriptions of stall precursors and its development with time. Results showed that the vaneless region of the centrifugal compressor is the most critical location affected by stall. It was found that the tip leakage flow and the back flow impingement are the main cause of the stall development at the impeller exit area for centrifugal compressors. The results of the axial compressor simulations indicated that the early separated flow combined with the tip leakage flow can block the impeller passages during stall.

  13. ANALYSIS WITH MSC ADAMS OF A 5-FINGER AND 3-PHALANX /FINGER UNDER-ACTUATEDMECHANICAL HAND

    Directory of Open Access Journals (Sweden)

    Gheorghe POPESCU

    2013-05-01

    Full Text Available This paper studies the analysis with MSC ADAMS of a 5-fingered and 3-phalanx/finger underactuatedmechanical hand, designed by the author to work on industrial robots. Moreover, in order to increasegrasping safety in the automated handling process, the author has fitted each finger with a locking sequence inthe final phase of grasping. Thus, the mechanism of mechanical hand is considered to be a mechanical systemand is treated like a set of rigid bodies connected by mechanical linkages and elastic elements. To model andsimulate this mechanism with MSC ADAMS programme, the author covered the following stages: constructionof the model, testing-simulation, validation, finishing, parameterization, and optimization

  14. Fluid dynamics and mass transfer in a gas centrifuge

    International Nuclear Information System (INIS)

    Conlisk, A.T.; Foster, M.R.; Walker, J.D.A.

    1982-01-01

    The fluid motion, temperature distribution and the mass-transfer problem of a binary gas mixture in a rapidly rotating centrifuge are investigated. Solutions for the velocity, temperature and mass-fraction fields within the centrifuge are obtained for mechanically or thermally driven centrifuges. For the mass-transfer problem, a detailed analysis of the fluid-mechanical boundary layers is required, and, in particular, mass fluxes within the boundary layers are obtained for a wide range of source-sink geometries. Solutions to the mass-transfer problem are obtained for moderately and strongly forced flows in the container; the dependence of the separation (or enrichment) factor on centrifuge configuration, rotational speed and fraction of the volumetric flow rate extracted at the product port (the cut) are predicted. (author)

  15. Convective instabilities in liquid centrifugation for nuclear wastes separation

    Energy Technology Data Exchange (ETDEWEB)

    Camassa, R. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    The separation of fission products from liquid solutions using centrifugal forces may prove an effective alternative to chemical processing in cases where radioactive materials necessitate minimal mixed-waste products or when allowing access to sophisticated chemical processing is undesirable. This investigation is a part of the effort to establish the feasibility of using liquid centrifugation for nuclear waste separation in the Accelerator Driven Energy Production (ADEP) program. A number of fundatmental issues in liquid centrifugation with radioactive elements need to be addressed in order to validate the approach and provide design criteria for experimental liquid salt (LiF and BeF{sub 2}) centrifuge. The author concentrates on one such issue, the possible onset of convective instabilities which could inhibit separation.

  16. Cell therapy medicinal product regulatory framework in Europe and its application for MSC based therapy development

    Directory of Open Access Journals (Sweden)

    Janis eAncans

    2012-08-01

    Full Text Available Advanced therapy medicinal products (ATMPs, including cell therapy products, form a new class of medicines in the European Union. Since ATMPs are at the forefront of scientific innovation in medicine, specific regulatory framework has been developed for these medicines and implemented from 2009. The Committee for Advanced Therapies (CAT has been established at European Medicines Agency (EMA for centralized classification, certification and evaluation procedures, and other ATMP related tasks. Guidance documents, initiatives and interaction platforms are available to make the new framework more accessible for small and medium-sized enterprises, academia, hospitals and foundations. Good understanding of centralised and national components of the regulatory system is required to plan product development. It is in the best interests of cell therapy developers to utilise provided resources starting with the preclinical stage. Whilst there have not been mesenchymal stem cell (MSC based medicine authorisations in the EU, three MSC products have received marketing approval in other regions since 2011. Information provided on regulatory requirements, procedures and initiatives is aimed to facilitate MSC based medicinal product development and authorisation in the EU.

  17. Human Powered Centrifuge

    Science.gov (United States)

    Mulenburg, Gerald M. (Inventor); Vernikos, Joan (Inventor)

    1997-01-01

    A human powered centrifuge has independently established turntable angular velocity and human power input. A control system allows excess input power to be stored as electric energy in a battery or dissipated as heat through a resistors. In a mechanical embodiment, the excess power is dissipated in a friction brake.

  18. A fuzzy controlled three-phase centrifuge for waste separation

    International Nuclear Information System (INIS)

    Parkinson, W.J.; Smith, R.E.; Miller, N.

    1998-02-01

    The three-phase centrifuge technology discussed in this paper was developed by Neal Miller, president of Centech, Inc. The three-phase centrifuge is an excellent device for cleaning up oil field and refinery wastes which are typically composed of hydrocarbons, water, and solids. The technology is unique. It turns the waste into salable oil, reusable water, and landfill-able solids. No secondary waste is produced. The problem is that only the inventor can set up and run the equipment well enough to provide an optimal cleanup. Demand for this device has far exceeded a one man operation. There is now a need for several centrifuges to be operated at different locations at the same time. This has produced a demand for an intelligent control system, one that could replace a highly skilled operator, or at least supplement the skills of a less experienced operator. The control problem is ideally suited to fuzzy logic, since the centrifuge is a highly complicated machine operated entirely by the skill and experience of the operator. A fuzzy control system was designed for and used with the centrifuge

  19. Fabrication of Al/Diamond Particles Functionally Graded Materials by Centrifugal Sintered-Casting Method

    International Nuclear Information System (INIS)

    Watanabe, Yoshimi; Shibuya, Masafumi; Sato, Hisashi

    2013-01-01

    The continuous graded structure of functionally graded materials (FGMs) can be created under a centrifugal force. Centrifugal sintered-casting (CSC) method, proposed by the authors, is one of the fabrication methods of FGM under centrifugal force. This method is a combination of the centrifugal sintering method and centrifugal casting method. In this study, Al/diamond particle FGM was fabricated by the proposed method.

  20. Quasi‐steady centrifuge method for unsaturated hydraulic properties

    Science.gov (United States)

    Caputo, Maria C.; Nimmo, John R.

    2005-01-01

    We have developed the quasi‐steady centrifuge (QSC) method as a variation of the steady state centrifuge method that can be implemented simply and inexpensively with greater versatility in terms of sample size and other features. It achieves these advantages by somewhat relaxing the criterion for steadiness of flow through the sample. This compromise entails an increase in measurement uncertainty but to a degree that is tolerable in most applications. We have tested this new approach with an easily constructed apparatus to establish a quasi‐steady flow of water in unsaturated porous rock samples spinning in a centrifuge, obtaining measurements of unsaturated hydraulic conductivity and water retention that agree with results of other methods. The QSC method is adaptable to essentially any centrifuge suitable for hydrogeologic applications, over a wide range of sizes and operating speeds. The simplified apparatus and greater adaptability of this method expands the potential for exploring situations that are common in nature but have been the subject of few laboratory investigations.

  1. Quasi-steady centrifuge method for unsaturated hydraulic properties

    Science.gov (United States)

    Caputo, Maria C.; Nimmo, John R.

    2005-11-01

    We have developed the quasi-steady centrifuge (QSC) method as a variation of the steady state centrifuge method that can be implemented simply and inexpensively with greater versatility in terms of sample size and other features. It achieves these advantages by somewhat relaxing the criterion for steadiness of flow through the sample. This compromise entails an increase in measurement uncertainty but to a degree that is tolerable in most applications. We have tested this new approach with an easily constructed apparatus to establish a quasi-steady flow of water in unsaturated porous rock samples spinning in a centrifuge, obtaining measurements of unsaturated hydraulic conductivity and water retention that agree with results of other methods. The QSC method is adaptable to essentially any centrifuge suitable for hydrogeologic applications, over a wide range of sizes and operating speeds. The simplified apparatus and greater adaptability of this method expands the potential for exploring situations that are common in nature but have been the subject of few laboratory investigations.

  2. New type of centrifugal extractor

    International Nuclear Information System (INIS)

    Miyauchi, T.; Tolich, A.

    1975-01-01

    The main principles of a centrifugal extractor design which can be used in the reprocessing of spent fuel with high degree of burning out are given. The extractor consists of two rotating coaxial cylinders. The contact of liquid phases is done in the circular space between the cylinders. By the cylinder rotating the phases are dispersed and the interface, as well as the extraction rate is increased. The given principles of the extractor design are realized in two simplified laboratory installations. The preliminary data obtained point out that much greater rates of the phases contact are achieved in centrifugal extractors than in extraction columns

  3. Centrifugation and the Manhattan Project

    Science.gov (United States)

    Reed, Cameron

    2009-05-01

    A study of U. S. Army Manhattan Engineer District documents reveals that consideration of centrifugation as a means of uranium enrichment during World War II was considerably more extensive than is commonly appreciated. By the time the centrifuge project was abandoned in early 1944 a full-scale prototype unit had been fabricated and tested at near-production speeds, enrichments of close to theoretically-expected levels had been demonstrated with pilot-plant units, and plans for production plants had been developed. This paper will review the history of this little-known aspect of the Project and examine the circumstances of how it came to be discontinued.

  4. MEANS FOR DETERMINING CENTRIFUGE ALIGNMENT

    Science.gov (United States)

    Smith, W.Q.

    1958-08-26

    An apparatus is presented for remotely determining the alignment of a centrifuge. The centrifage shaft is provided with a shoulder, upon which two followers ride, one for detecting radial movements, and one upon the shoulder face for determining the axial motion. The followers are attached to separate liquid filled bellows, and a tube connects each bellows to its respective indicating gage at a remote location. Vibrations produced by misalignment of the centrifuge shaft are transmitted to the bellows, and tbence through the tubing to the indicator gage. This apparatus is particularly useful for operation in a hot cell where the materials handled are dangerous to the operating personnel.

  5. Tropic responses of Phycomyces sporangiophores to gravitational and centrifugal stimuli.

    Science.gov (United States)

    DENNISON, D S

    1961-09-01

    A low-speed centrifuge was used to study the tropic responses of Phycomyces sporangiophores in darkness to the stimulus of combined gravitational and centrifugal forces. If this stimulus is constant the response is a relatively slow tropic reaction, which persists for up to 12 hours. The response is accelerated by increasing the magnitude of the gravitational-centrifugal force. A wholly different tropic response, the transient response, is elicited by an abrupt change in the gravitational-centrifugal stimulus. The transient response has a duration of only about 6 min. but is characterized by a high bending speed (about 5 degrees /min.). An analysis of the distribution of the transient response along the growing zone shows that the active phase of the response has a distribution similar to that of the light sensitivity for the light-growth and phototropic responses. Experiments in which sporangiophores are centrifuged in an inert dense fluid indicate that the sensory mechanism of the transient response is closely related to the physical deformation of the growing zone caused by the action of the gravitational-centrifugal force on the sporangiophore as a whole. However, the response to a steady gravitational-centrifugal force is most likely not connected with this deformation, but is probably triggered by the shifting of regions or particles of differing density relative to one another inside the cell.

  6. Centrifuge separation effect on bacterial indicator reduction in dairy manure.

    Science.gov (United States)

    Liu, Zong; Carroll, Zachary S; Long, Sharon C; Roa-Espinosa, Aicardo; Runge, Troy

    2017-04-15

    Centrifugation is a commonly applied separation method for manure processing on large farms to separate solids and nutrients. Pathogen reduction is also an important consideration for managing manure. Appropriate treatment reduces risks from pathogen exposure when manure is used as soil amendments or the processed liquid stream is recycled to flush the barn. This study investigated the effects of centrifugation and polymer addition on bacterial indicator removal from the liquid fraction of manure slurries. Farm samples were taken from a manure centrifuge processing system. There were negligible changes of quantified pathogen indicator concentrations in the low-solids centrate compared to the influent slurry. To study if possible improvements could be made to the system, lab scale experiments were performed investigating a range of g-forces and flocculating polymer addition. The results demonstrated that polymer addition had a negligible effect on the indicator bacteria levels when centrifuged at high g forces. However, the higher g force centrifugation was capable of reducing bacterial indicator levels up to two-log 10 in the liquid stream of the manure, although at speeds higher than typical centrifuge operations currently used for manure processing applications. This study suggests manure centrifuge equipment could be redesigned to provide pathogen reduction to meet emerging issues, such as zoonotic pathogen control. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. The modeling experience of fuel element units operation under MSC.MARC and MENTAT 2008R1

    International Nuclear Information System (INIS)

    Kulakov, G.; Kashirin, B.; Kosaurov, A.; Konovalov, Y.; Kuznetsov, A.; Medvedev, A.; Novikov, V.; Vatulin, A.

    2009-01-01

    MSC Software is leading developer of CAE-software in the world, so behaviour of fuel elements modeling with MSC.MARC use is of great practical importance. Behaviour of fuel elements usually is modeled in the elastic-viscous-plastic statement with account on fuel swelling during irradiation. For container type fuel elements contact interaction between fuel pellets and cladding or other parts of fuel element in top and bottom plugs must be in account. Results of simulated behaviour of various type fuel elements - container type fuel elements for PWR and RBMK reactors, dispersion type fuel elements for research reactors are presented. (authors)

  8. A centrifuge CO2 pellet cleaning system

    International Nuclear Information System (INIS)

    Foster, C.A.; Fisher, P.W.; Nelson, W.D.; Schechter, D.E.

    1993-01-01

    Centrifuge-based cryogenic pellet accelerator technology, originally developed at Oak Ridge National Laboratory (ORNL) for the purpose of refueling fusion reactors with high-speed pellets of frozen deuterium/tritium,is now being developed as a method of cleaning without the use of conventional solvents. In these applications large quantities of pellets made of frozen CO 2 or argon are accelerated in a high-speed rotor. The accelerated pellet stream is used to clean or etch surfaces. The advantage of this system is that the spent pellets and debris resulting from the cleaning process can be filtered leaving only the debris for disposal. This paper discusses the centrifuge CO 2 pellet cleaning system, the physics model of the pellet impacting the surface, the centrifuge apparatus, and some initial cleaning and etching tests

  9. Profiling post-centrifugation delay of serum and plasma with antibody bead arrays.

    Science.gov (United States)

    Qundos, Ulrika; Hong, Mun-Gwan; Tybring, Gunnel; Divers, Mark; Odeberg, Jacob; Uhlen, Mathias; Nilsson, Peter; Schwenk, Jochen M

    2013-12-16

    Several biobanking initiatives have emerged to create extensive collections of specimen for biomedical studies and various analytical platforms. An affinity proteomic analysis with antibody suspension bead arrays was conducted to investigate the influence of the pre-analytical time and temperature conditions on blood derived samples. Serum and EDTA plasma prepared from 16 individuals was centrifuged and aliquots were kept either at 4°C or in ambient temperature for 1h and up to 36h prior to first storage. Multiplexed protein profiles of post-centrifugation delay were generated in 384 biotinylated samples using 373 antibodies that targeted 343 unique proteins. Very few profiles were observed as significantly altered by the studied temperature and time intervals. Single binder and sandwich assays revealed decreasing levels of caldesmon 1 (CALD1) related to EDTA standard tubes and prolonged post-centrifugation delay of 36h. Indications from changes in CALD1 levels require further confirmation in independent material, but the current data suggests that samples should preferentially be frozen during the day of collection when to be profiled with antibody arrays selected for this study. Affinity-based profiling of serum and plasma by microarray assays can provide unique opportunities for the discovery of biomarkers. It is though often not known how differences in sample handling after collection influence the downstream analysis. By profiling three types of blood preparations for alterations in protein profiles with respect to time and temperature post centrifugation, we addressed an important component in the analysis and of such specimen. We believe that this analysis adds valuable information to be considered when biobanking blood derived samples. This article is part of a Special Issue entitled: Standardization and Quality Control in Proteomics. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Feasibility of a Short-Arm Centrifuge for Mouse Hypergravity Experiments.

    Science.gov (United States)

    Morita, Hironobu; Obata, Koji; Abe, Chikara; Shiba, Dai; Shirakawa, Masaki; Kudo, Takashi; Takahashi, Satoru

    2015-01-01

    To elucidate the pure impact of microgravity on small mammals despite uncontrolled factors that exist in the International Space Station, it is necessary to construct a 1 g environment in space. The Japan Aerospace Exploration Agency has developed a novel mouse habitat cage unit that can be installed in the Cell Biology Experiment Facility in the Kibo module of the International Space Station. The Cell Biology Experiment Facility has a short-arm centrifuge to produce artificial 1 g gravity in space for mouse experiments. However, the gravitational gradient formed inside the rearing cage is larger when the radius of gyration is shorter; this may have some impact on mice. Accordingly, biological responses to hypergravity induced by a short-arm centrifuge were examined and compared with those induced by a long-arm centrifuge. Hypergravity induced a significant Fos expression in the central nervous system, a suppression of body mass growth, an acute and transient reduction in food intake, and impaired vestibulomotor coordination. There was no difference in these responses between mice raised in a short-arm centrifuge and those in a long-arm centrifuge. These results demonstrate the feasibility of using a short-arm centrifuge for mouse experiments.

  11. Deep-body temperature changes in rats exposed to chronic centrifugation.

    Science.gov (United States)

    Oyama, J.; Platt, W. T.; Holland, V. B.

    1971-01-01

    Deep-body temperature was monitored continuously by implant biotelemetry in unrestrained rats before, during, and after exposure to prolonged and almost continuous centrifugation. Rats subjected to centrifugation for the first time at various G loads ranging up to 2.5 G show a rapid and significant fall in temperature which is sustained below normal levels for periods as long as 3 days. The magnitude of the temperature fall and the recovery time were generally proportional to the G load imposed. The initial fall and recovery of body temperature closely parallels the decrease in food consumption and to a lesser degree the decrease in body mass experienced by centrifuged rats. After exposure to 2 weeks of centrifugation, rats show either no change or only a small transient increase in temperature when decelerated to a lower G level or when returned to normal gravity. Rats repeatedly exposed to centrifugation consistently showed a smaller temperature response compared to the initial exposure. Implant temperature biotelemetry has been found to be a sensitive, reliable, and extremely useful technique for assessing the initial stress of centrifugation and in monitoring the time course of recovery and acclimation of rats to increase as well as*decrease G.

  12. Centrifugal compressor case study

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, B.

    2010-10-15

    Three centrifugal compressors at a pipeline station were retrofitted with higher head impellers in 2008. The owners of the station experienced vibration problems over the following 2 years that caused transmitter and position failures that were assumed to be flow-induced pulsations. A vibration and pulsation analysis indicated that the shell mode piping vibration excited by the blade pass pulsation was responsible for the failures. This study outlined factors that contributed to the vibration problem. Interferences between the compressor and shell mode piping natural frequencies were predicted, and potential excitation sources were examined. The study demonstrated how centrifugal vibration analyses can be used during the design phase to avoid costly adjustments. Recommendations included the addition of stiffeners to alter the shell modes, and the addition of constrained layer damping material to reduce resonant responses. 2 refs., 1 tab., 12 figs.

  13. Microcomputer-based instrument for the detection and analysis of precession motion in a gas centrifuge machine. Revision 1

    International Nuclear Information System (INIS)

    Paulus, S.S.

    1986-03-01

    The Centrifuge Procession Analyzer (CPA) is a microcomputer-based instrument which detects precession motion in a gas centrifuge machine and calculates the amplitude and frequency of precession. The CPA consists of a printed circuit board which contains signal-conditioning circuitry and a 24-bit counter and an INTEL iSBC 80/24 single/board computer. Pression motion is detected by monitoring a signal generated by a variable reluctance pick-up coil in the top of the centrifuge machine. This signal is called a Fidler signal. The initial Fidler signal triggers a counter which is clocked by a high-precision, 20.000000-MHz, temperature-controlled, crystal oscillator. The contents of the counter are read by the computer and the counter reset after every ten Fidler signals. The speed of the centrifuge machine and the amplitude and frequency of precession are calculated and the results are displayed on a liquid crystal display on the front panel of the CPA. The report contains results from data generated by a Fidler signal simulator and data taken when the centrifuge was operated under three test conditions: (1) nitrogen gas during drive-up, steady state, and drive-down; (2) xenon gas during slip test, steady state, and the addition of gas; and (3) no gas during steady state. The qualitative results were consistent with experience with centrifuge machines using UF 6 in that the amplitude of precession increased and the frequency of precession decreased during drive-up, drive-down and the slip check. The magnitude of the amplitude and frequency of precession were proportional to the molecular weight of the gases in steady state

  14. 21 CFR 864.9285 - Automated cell-washing centrifuge for immuno-hematology.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated cell-washing centrifuge for immuno... Establishments That Manufacture Blood and Blood Products § 864.9285 Automated cell-washing centrifuge for immuno-hematology. (a) Identification. An automated cell-washing centrifuge for immuno-hematology is a device used...

  15. Compound drum for a centrifugal separator

    International Nuclear Information System (INIS)

    1972-01-01

    This invention concerns a method for centrifugal separation of UF 6 . The invention provides a composite drum capable of rapid rotation for use in a centrifugal separating arrangement for gaseous materials. The drum is provided with a first drum section comprised of a metal and a second drum section comprised of a fiber-reinforced synthetic material. The second drum section is applied on the outside peripheral surface of the first drum section, where the second drum section is provided with a number of annular components, each of which is shorter than the first drum section

  16. Centrifuge impact cratering experiment 5

    Science.gov (United States)

    1984-01-01

    Transient crates motions, cratering flow fields, crates dynamics, determining impact conditions from total crater welt, centrifuge quarter-space cratering, and impact cratering mechanics research is documented.

  17. Labeling of mesenchymal stem cells for MRI with single-cell sensitivity

    Directory of Open Access Journals (Sweden)

    Ariza de Schellenberger A

    2016-04-01

    Full Text Available Angela Ariza de Schellenberger,1 Harald Kratz,1 Tracy D Farr,2,3 Norbert Löwa,4 Ralf Hauptmann,1 Susanne Wagner,1 Matthias Taupitz,1 Jörg Schnorr,1 Eyk A Schellenberger1 1Department of Radiology, 2Department of Experimental Neurology, Center for Stroke Research Berlin, Charité – Universitätsmedizin Berlin, Berlin, Germany; 3School of Life Sciences, University of Nottingham, Medical School, Nottingham, UK; 4Department of Biomagnetic Signals, Physikalisch-Technische Bundesanstalt Berlin, Berlin, Germany Abstract: Sensitive cell detection by magnetic resonance imaging (MRI is an important tool for the development of cell therapies. However, clinically approved contrast agents that allow single-cell detection are currently not available. Therefore, we compared very small iron oxide nanoparticles (VSOP and new multicore carboxymethyl dextran-coated iron oxide nanoparticles (multicore particles, MCP designed by our department for magnetic particle imaging (MPI with discontinued Resovist® regarding their suitability for detection of single mesenchymal stem cells (MSC by MRI. We achieved an average intracellular nanoparticle (NP load of >10 pg Fe per cell without the use of transfection agents. NP loading did not lead to significantly different results in proliferation, colony formation, and multilineage in vitro differentiation assays in comparison to controls. MRI allowed single-cell detection using VSOP, MCP, and Resovist® in conjunction with high-resolution T2*-weighted imaging at 7 T with postprocessing of phase images in agarose cell phantoms and in vivo after delivery of 2,000 NP-labeled MSC into mouse brains via the left carotid artery. With optimized labeling conditions, a detection rate of ~45% was achieved; however, the experiments were limited by nonhomogeneous NP loading of the MSC population. Attempts should be made to achieve better cell separation for homogeneous NP loading and to thus improve NP

  18. Centrifugal pumps: fundamentals and classification

    International Nuclear Information System (INIS)

    Solar Manuel, A. M.

    2009-01-01

    Centrifugal pumps are usually employed to impulse water to elevate it, dose it or give it pressure or speed. They can be used with clean water or loaded with high solid concentration and don't work properly with air or another gas flow. There are another less used pumps, coming from volumetric or ram pumps to magnetic ones for specific uses. Centrifugal ones are rotokinetic pumps, like peripherical or lateral channel pumps. They work in a different way that non rotational kinetic ones and static ones. The work approaches their pre definition, selection, installation, operation and maintenance. It also review their morphology, hidromechanic principles and the basic elements pumps are made of. (Author)

  19. Automated cellular sample preparation using a Centrifuge-on-a-Chip.

    Science.gov (United States)

    Mach, Albert J; Kim, Jae Hyun; Arshi, Armin; Hur, Soojung Claire; Di Carlo, Dino

    2011-09-07

    The standard centrifuge is a laboratory instrument widely used by biologists and medical technicians for preparing cell samples. Efforts to automate the operations of concentration, cell separation, and solution exchange that a centrifuge performs in a simpler and smaller platform have had limited success. Here, we present a microfluidic chip that replicates the functions of a centrifuge without moving parts or external forces. The device operates using a purely fluid dynamic phenomenon in which cells selectively enter and are maintained in microscale vortices. Continuous and sequential operation allows enrichment of cancer cells from spiked blood samples at the mL min(-1) scale, followed by fluorescent labeling of intra- and extra-cellular antigens on the cells without the need for manual pipetting and washing steps. A versatile centrifuge-analogue may open opportunities in automated, low-cost and high-throughput sample preparation as an alternative to the standard benchtop centrifuge in standardized clinical diagnostics or resource poor settings.

  20. Multifunctional centrifugal grinding unit

    Science.gov (United States)

    Sevostyanov, V. S.; Uralskij, V. I.; Uralskij, A. V.; Sinitsa, E. V.

    2018-03-01

    The article presents scientific and engineering developments of multifunctional centrifugal grinding unit in which the selective effect of grinding bodies on the crushing material is realized, depending on its physical and mechanical characteristics and various schemes for organizing the technological process

  1. Separation of Nanoparticles in Aqueous Multiphase Systems through Centrifugation

    KAUST Repository

    Akbulut, Ozge; Mace, Charles R.; Martinez, Ramses V.; Kumar, Ashok A.; Nie, Zhihong; Patton, Matthew R.; Whitesides, George M.

    2012-01-01

    This paper demonstrates the use of aqueous multiphase systems (MuPSs) as media for rate-zonal centrifugation to separate nanoparticles of different shapes and sizes. The properties of MuPSs do not change with time or during centrifugation; this stability facilitates sample collection after separation. A three-phase system demonstrates the separation of the reaction products (nanorods, nanospheres, and large particles) of a synthesis of gold nanorods, and enriches the nanorods from 48 to 99% in less than ten minutes using a benchtop centrifuge. © 2012 American Chemical Society.

  2. Separation of Nanoparticles in Aqueous Multiphase Systems through Centrifugation

    KAUST Repository

    Akbulut, Ozge

    2012-08-08

    This paper demonstrates the use of aqueous multiphase systems (MuPSs) as media for rate-zonal centrifugation to separate nanoparticles of different shapes and sizes. The properties of MuPSs do not change with time or during centrifugation; this stability facilitates sample collection after separation. A three-phase system demonstrates the separation of the reaction products (nanorods, nanospheres, and large particles) of a synthesis of gold nanorods, and enriches the nanorods from 48 to 99% in less than ten minutes using a benchtop centrifuge. © 2012 American Chemical Society.

  3. Centrifugal compressor design for electrically assisted boost

    International Nuclear Information System (INIS)

    Yang, M Y; Martinez-Botas, R F; Zhuge, W L; Qureshi, U; Richards, B

    2013-01-01

    Electrically assisted boost is a prominent method to solve the issues of transient lag in turbocharger and remains an optimized operation condition for a compressor due to decoupling from turbine. Usually a centrifugal compressor for gasoline engine boosting is operated at high rotational speed which is beyond the ability of an electric motor in market. In this paper a centrifugal compressor with rotational speed as 120k RPM and pressure ratio as 2.0 is specially developed for electrically assisted boost. A centrifugal compressor including the impeller, vaneless diffuser and the volute is designed by meanline method followed by 3D detailed design. Then CFD method is employed to predict as well as analyse the performance of the design compressor. The results show that the pressure ratio and efficiency at design point is 2.07 and 78% specifically

  4. The duration of effect of centrifuge concentrated intravitreal triamcinolone acetonide.

    Science.gov (United States)

    Ober, Michael D; Valijan, Sevak

    2013-04-01

    To estimate the duration of activity for intravitreal triamcinolone injected with a new technique using centrifuge concentration (Centrifuge concentrated IntraVitreal Triamcinolone, C-IVT). All injections were performed by a single surgeon (M.D.O.) using a 30-gauge needle. A vial of Triesence (triamcinolone; Alcon Laboratories, Fort Worth, TX) was drawn into a 1-mL syringe and the plunger cut off. The contents were spun in a centrifuge, and a second plunger was placed. Records of all patients receiving C-IVT with 0.05 mL or 0.1 mL from January 1, 2009, through December 31, 2009, were retrospectively reviewed. Eighty-four injections from 69 eyes of 57 patients were included. Sixty-nine injections from 54 eyes of 44 patients received 0.05 mL of C-IVT, whereas 15 injections from 15 eyes of 13 patients received 0.1 mL of C-IVT. Triamcinolone acetonide was still visualized in the vitreous on an average of 5.0 ± 2.4 months (median 5 months) after 0.05 mL of C-IVT and 8.3 ± 4.0 months (median 8 months) after 0.1 mL of C-IVT during follow-up visits. The longest duration recorded was 14 months for the 0.05-mL group and 18 months for the 0.l-mL group. The C-IVT results in a long duration of effect that seems to be greater than previously published techniques. It may be considered for patients requiring chronic steroid therapy, in which the benefits of long-term intravitreal steroids are believed to outweigh their risk.

  5. Effects of centrifugation on gonadal and adrenocortical steroids in rats

    Science.gov (United States)

    Kakihana, R.; Butte, J. C.

    1980-01-01

    Many endocrine systems are sensitive to external changes in the environment. Both the pituitary adrenal and pituitary gonadal systems are affected by stress including centrifugation stress. The effect of centrifugation on the pituitary gonadal and pituitary adrenocortical systems was examined by measuring the gonadal and adrenal steroids in the plasma and brain following different duration and intensity of centrifugation stress in rats. Two studies were completed and the results are presented. The second study was carried out to describe the developmental changes of brain, plasma and testicular testosterone and dihydrotestosterone in Sprague Dawley rats so that the effect of centrifugation stress on the pituitary gonadal syatem could be better evaluated in future studies.

  6. Thermal hydrodynamic analysis of a countercurrent gas centrifuge

    International Nuclear Information System (INIS)

    Andrade, Delvonei Alves de

    1999-01-01

    The influence of the thermal countercurrent on the separative performance of countercurrent centrifuges is treated in this work. The methodology used consists in modeling the gas flow inside the rotor under thermal boundary conditions supplied by the structural thermal model. The gas flow model, also called hydrodynamical model, is based on the Finite Volume Method for cylindrical geometry with azimuthal symmetry. The structural thermal model is based on the Nodal Method and take into account simultaneously, the conduction convection and radiation phenomena. The procedure adopted for this study consisted in the definition of the operational and geometric conditions of a centrifuge which was used as a pattern to the accomplished analysis. This configuration, called 'Standard Centrifuge', was used for the accomplishment of several simulations where the importance of the realistic boundary thermal conditions for the numerical evaluation of the centrifuge separative capacity was evidenced. A selective alteration for the optical properties based on simple engineering procedures was proposed. An improvement of 5% was obtained with this alteration. (author)

  7. Feasibility of a Short-Arm Centrifuge for Mouse Hypergravity Experiments.

    Directory of Open Access Journals (Sweden)

    Hironobu Morita

    Full Text Available To elucidate the pure impact of microgravity on small mammals despite uncontrolled factors that exist in the International Space Station, it is necessary to construct a 1 g environment in space. The Japan Aerospace Exploration Agency has developed a novel mouse habitat cage unit that can be installed in the Cell Biology Experiment Facility in the Kibo module of the International Space Station. The Cell Biology Experiment Facility has a short-arm centrifuge to produce artificial 1 g gravity in space for mouse experiments. However, the gravitational gradient formed inside the rearing cage is larger when the radius of gyration is shorter; this may have some impact on mice. Accordingly, biological responses to hypergravity induced by a short-arm centrifuge were examined and compared with those induced by a long-arm centrifuge. Hypergravity induced a significant Fos expression in the central nervous system, a suppression of body mass growth, an acute and transient reduction in food intake, and impaired vestibulomotor coordination. There was no difference in these responses between mice raised in a short-arm centrifuge and those in a long-arm centrifuge. These results demonstrate the feasibility of using a short-arm centrifuge for mouse experiments.

  8. Cell therapy medicinal product regulatory framework in Europe and its application for MSC-based therapy development

    Science.gov (United States)

    Ancans, Janis

    2012-01-01

    Advanced therapy medicinal products (ATMPs), including cell therapy products, form a new class of medicines in the European Union. Since the ATMPs are at the forefront of scientific innovation in medicine, specific regulatory framework has been developed for these medicines and implemented from 2009. The Committee for Advanced Therapies (CAT) has been established at the European Medicines Agency (EMA) for centralized classification, certification and evaluation procedures, and other ATMP-related tasks. Guidance documents, initiatives, and interaction platforms are available to make the new framework more accessible for small- and medium-sized enterprises, academia, hospitals, and foundations. Good understanding of the centralized and national components of the regulatory system is required to plan product development. It is in the best interests of the cell therapy developers to utilize the resources provided starting with the pre-clinical stage. Whilst there have been no mesenchymal stem cell (MSC)-based medicine authorizations in the EU, three MSC products have received marketing approval in other regions since 2011. The information provided on the regulatory requirements, procedures, and initiatives is aimed at facilitating MSC-based medicinal product development and authorization in the EU. PMID:22912639

  9. Thermally-controlled centrifuge for isotopic separation

    International Nuclear Information System (INIS)

    Cenedese, A.; Cunsolo, D.

    1976-01-01

    Among the various methods proposed to obtain lighter component enrichment in the isotopic separation of uranium, ultracentrifugation is becoming more and more interesting today, as this process becomes a useful alternate method to gaseous diffusion. The ultracentrifuge main gas-dynamic features are investigated in the present study. In particular, the field inside the centrifuge has been subdivided into three axial zones: an internal central zone, characterized by an essentially axial flow; two external zones, near the two caps of the centrifuge; two intermediate zones, of a length of the order of the radius. For the analytical solution the linearized Navier-Stokes equations have been considered. The central zone flow is solved by separating the independent variables; the corresponding eigenvalue problem has been solved numerically. A series of eigensolutions which satisfy boundary conditions at the walls of the cylinder has been calculated. An integral method for the superimposition of the above mentioned eigensolutions is proposed in order to satisfy the conditions at the tops for thermally-controlled centrifuges. (author)

  10. EM Task 9 - Centrifugal Membrane Filtration

    International Nuclear Information System (INIS)

    Stevens, B.G.; Stepan, D.J.; Hetland, M.D.

    1998-01-01

    This project is designed to establish the utility of a novel centrifugal membrane filtration technology for the remediation of liquid mixed waste streams at US Department of Energy (DOE) facilities in support of the DOE Environmental Management (EM) program. The Energy and Environmental Research Center (EERC) has teamed with SpinTek Membrane Systems, Inc., a small business and owner of the novel centrifugal membrane filtration technology, to establish the applicability of the technology to DOE site remediation and the commercial viability of the technology for liquid mixed waste stream remediation. The technology is a uniquely configured process that makes use of ultrafiltration and centrifugal force to separate suspended and dissolved solids from liquid waste streams, producing a filtered water stream and a low-volume contaminated concentrate stream. This technology has the potential for effective and efficient waste volume minimization, the treatment of liquid tank wastes, the remediation of contaminated groundwater plumes, and the treatment of secondary liquid waste streams from other remediation processes, as well as the liquid waste stream generated during decontamination and decommissioning activities

  11. Influence of the centrifuge time of primary plasma tubes on routine coagulation testing.

    Science.gov (United States)

    Lippi, Giuseppe; Salvagno, Gian Luca; Montagnana, Martina; Manzato, Franco; Guidi, Gian Cesare

    2007-07-01

    Preparation of blood specimens is a major bottleneck in the laboratory throughput. Reliable strategies for reducing the time required for specimen processing without affecting quality should be acknowledged, especially for laboratories performing stat analyses. The present investigation was planned to establish a minimal suitable centrifuge time for primary samples collected for routine coagulation testing. Five sequential primary vacuum tubes containing 0.109 mol/l buffered trisodium citrate were collected from 10 volunteers and were immediately centrifuged on a conventional centrifuge at 1500 x g, at room temperature for 1, 2, 5, 10 and 15 min, respectively. Hematological and routine coagulation testing, including prothrombin time, activated partial thromboplastin time and fibrinogen, were performed. The centrifugation time was inversely associated with residual blood cell elements in plasma, especially platelets. Statistically significant variations from the reference 15-min centrifuge specimens were observed for fibrinogen in samples centrifuged for 5 min at most and for the activated partial thromboplastin time in samples centrifuged for 2 min at most. Meaningful biases related to the desirable bias were observed for fibrinogen in samples centrifuged for 2 min at most, and for the activated partial thromboplastin time in samples centrifuged for 1 min at most. According to our experimental conditions, a 5-10 min centrifuge time at 1500 x g may be suitable for primary tubes collected for routine coagulation testing.

  12. Silk-ionomer and silk-tropoelastin hydrogels as charged three-dimensional culture platforms for the regulation of hMSC response.

    Science.gov (United States)

    Calabrese, Rossella; Raia, Nicole; Huang, Wenwen; Ghezzi, Chiara E; Simon, Marc; Staii, Cristian; Weiss, Anthony S; Kaplan, David L

    2017-09-01

    The response of human bone marrow-derived mesenchymal stem cells (hMSCs) encapsulated in three-dimensional (3D) charged protein hydrogels was studied. Combining silk fibroin (S) with recombinant human tropoelastin (E) or silk ionomers (I) provided protein composite alloys with tunable physicochemical and biological features for regulating the bioactivity of encapsulated hMSCs. The effects of the biomaterial charges on hMSC viability, proliferation and chondrogenic or osteogenic differentiation were assessed. The silk-tropoelastin or silk-ionomers hydrogels supported hMSC viability, proliferation and differentiation. Gene expression of markers for chondrogenesis and osteogenesis, as well as biochemical and histological analysis, showed that hydrogels with different S/E and S/I ratios had different effects on cell fate. The negatively charged hydrogels upregulated hMSC chondrogenesis or osteogenesis, with or without specific differentiation media, and hydrogels with higher tropoelastin content inhibited the differentiation potential even in the presence of the differentiation media. The results provide insight on charge-tunable features of protein-based biomaterials to control hMSC differentiation in 3D hydrogels, as well as providing a new set of hydrogels for the compatible encapsulation and utility for cell functions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Scaling of rotation and isotope separation in a vacuum-arc centrifuge

    International Nuclear Information System (INIS)

    Prasad, R.R.; Krishnan, M.

    1987-01-01

    Scaling is described of rotation, plasma column size and separation in a vacuum-arc centrifuge. The vacuum-arc centrifuge is a magnetized, fulled ionized, quasineutral column of plasma. The source of plasma is a vacuum-arc discharge between a negatively biased cathode and a grounded mesh anode. Rigid-body rotation, induced by the J x B force, causes radial, centrifugal separation of isotopes in the plasma column. Salient features of a fluid model that provides an understanding of rotation and the concomitant isotope separation in the vacuum-arc centrifuge are described. Scaling of rotation and plasma column size is found be consistent with the model. Measurements of isotope separation, also found to agree with the predictions of the model, are presented. Results of a parametric analysis of isotope separation in such a vacuum-arc centrifuge, using the fluid model and the observed scaling laws, are described. An analysis of the energy cost of separation of the vacuum-arc centrifuge shows that it typically requires only 70 keV/separated atom. (orig.)

  14. Reduction of relative centrifugation force within injectable platelet-rich-fibrin (PRF) concentrates advances patients' own inflammatory cells, platelets and growth factors: the first introduction to the low speed centrifugation concept.

    Science.gov (United States)

    Choukroun, J; Ghanaati, S

    2018-02-01

    The aim of this study was to analyze systematically the influence of the relative centrifugation force (RCF) on leukocytes, platelets and growth factor release within fluid platelet-rich fibrin matrices (PRF). Systematically using peripheral blood from six healthy volunteers, the RCF was reduced four times for each of the three experimental protocols (I-III) within the spectrum (710-44 g), while maintaining a constant centrifugation time. Flow cytometry was applied to determine the platelets and leukocyte number. The growth factor concentration was quantified 1 and 24 h after clotting using ELISA. Reducing RCF in accordance with protocol-II (177 g) led to a significantly higher platelets and leukocytes numbers compared to protocol-I (710 g). Protocol-III (44 g) showed a highly significant increase of leukocytes and platelets number in comparison to -I and -II. The growth factors' concentration of VEGF and TGF-β1 was significantly higher in protocol-II compared to -I, whereas protocol-III exhibited significantly higher growth factor concentration compared to protocols-I and -II. These findings were observed among 1 and 24 h after clotting, as well as the accumulated growth factor concentration over 24 h. Based on the results, it has been demonstrated that it is possible to enrich PRF-based fluid matrices with leukocytes, platelets and growth factors by means of a single alteration of the centrifugation settings within the clinical routine. We postulate that the so-called low speed centrifugation concept (LSCC) selectively enriches leukocytes, platelets and growth factors within fluid PRF-based matrices. Further studies are needed to evaluate the effect of cell and growth factor enrichment on wound healing and tissue regeneration while comparing blood concentrates gained by high and low RCF.

  15. M.Sc. in Civil and Structural Engineering

    DEFF Research Database (Denmark)

    Clausen, Johan Christian

    The following pages contain a list of project ideas proposed by the scientific staff at the Department of Civil Engineering, Aalborg University, and a number of companies. Most of the project ideas in this catalogue may form the basis for long and short master projects as well as regular 3rd...... semester projects at the M.Sc. programme in Civil and Structural Engineering. Each project description provides a brief overview of the purpose as well as the main activities. Further, a weighting between theoretical analysis, experimental work and computer modelling has been proposed. Usually...... page. Furthermore, other ideas for projects may be discussed with a potential supervisor. Many private engineering companies have a homepage on which they state that they would like to collaborate with students on a master project....

  16. A 'smart' tube holder enables real-time sample monitoring in a standard lab centrifuge.

    Science.gov (United States)

    Hoang, Tony; Moskwa, Nicholas; Halvorsen, Ken

    2018-01-01

    The centrifuge is among the oldest and most widely used pieces of laboratory equipment, with significant applications that include clinical diagnostics and biomedical research. A major limitation of laboratory centrifuges is their "black box" nature, limiting sample observation to before and after centrifugation. Thus, optimized protocols require significant trial and error, while unoptimized protocols waste time by centrifuging longer than necessary or material due to incomplete sedimentation. Here, we developed an instrumented centrifuge tube receptacle compatible with several commercial benchtop centrifuges that can provide real-time sample analysis during centrifugation. We demonstrated the system by monitoring cell separations during centrifugation for different spin speeds, concentrations, buffers, cell types, and temperatures. We show that the collected data are valuable for analytical purposes (e.g. quality control), or as feedback to the user or the instrument. For the latter, we verified an adaptation where complete sedimentation turned off the centrifuge and notified the user by a text message. Our system adds new functionality to existing laboratory centrifuges, saving users time and providing useful feedback. This add-on potentially enables new analytical applications for an instrument that has remained largely unchanged for decades.

  17. Centrifugal analyzer development

    International Nuclear Information System (INIS)

    Burtis, C.A.; Bauer, M.L.; Bostick, W.D.

    1976-01-01

    The development of the centrifuge fast analyzer (CFA) is reviewed. The development of a miniature CFA with computer data analysis is reported and applications for automated diagnostic chemical and hematological assays are discussed. A portable CFA system with microprocessor was adapted for field assays of air and water samples for environmental pollutants, including ammonia, nitrates, nitrites, phosphates, sulfates, and silica. 83 references

  18. Horizontal vibrations of piles in a centrifuge

    International Nuclear Information System (INIS)

    Bourdin, B.

    1987-01-01

    The aim of the thesis is the study of soil dynamics for important structures like nuclear power plants, offshore platforms, dams etc. Experimental results of horizontal vibrations on a pile partially anchored in a soil scale model put into a centrifuge are presented. Mechanical similitude conditions from equilibrium equations or rheologic laws are described. After a description of testing equipment (centrifuge, electrodynamic excitator) experimental results are interpreted with a model. Non-linearities on frequency response curves are characterized [fr

  19. The commercial role for centrifuge enrichment

    International Nuclear Information System (INIS)

    Readle, P.H.; Wilcox, P.

    1987-01-01

    The enrichment market is extremely competitive and capacity greatly exceeds demand. BNFL [British Nuclear Fuels Ltd.] is in a unique position in having commercial experience of the two enrichment technologies currently used industrially: diffusion, and centrifuge enrichment through its associate company Urenco. In addition, BNFL is developing laser enrichment techniques as part of a UK development programme. The paper describes the enrichment market, briefly discusses the relative merits of the various methods of uranium enrichment and concludes that the gas centrifuge will be best able to respond to market needs for at least the remainder of the century. (author)

  20. Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

    Science.gov (United States)

    Mahl, Dirk; Diendorf, Jörg; Ristig, Simon; Greulich, Christina; Li, Zi-An; Farle, Michael; Köller, Manfred; Epple, Matthias

    2012-10-01

    Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly( N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 μg mL-1 induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  1. The standard centrifuge method accurately measures vulnerability curves of long-vesselled olive stems.

    Science.gov (United States)

    Hacke, Uwe G; Venturas, Martin D; MacKinnon, Evan D; Jacobsen, Anna L; Sperry, John S; Pratt, R Brandon

    2015-01-01

    The standard centrifuge method has been frequently used to measure vulnerability to xylem cavitation. This method has recently been questioned. It was hypothesized that open vessels lead to exponential vulnerability curves, which were thought to be indicative of measurement artifact. We tested this hypothesis in stems of olive (Olea europea) because its long vessels were recently claimed to produce a centrifuge artifact. We evaluated three predictions that followed from the open vessel artifact hypothesis: shorter stems, with more open vessels, would be more vulnerable than longer stems; standard centrifuge-based curves would be more vulnerable than dehydration-based curves; and open vessels would cause an exponential shape of centrifuge-based curves. Experimental evidence did not support these predictions. Centrifuge curves did not vary when the proportion of open vessels was altered. Centrifuge and dehydration curves were similar. At highly negative xylem pressure, centrifuge-based curves slightly overestimated vulnerability compared to the dehydration curve. This divergence was eliminated by centrifuging each stem only once. The standard centrifuge method produced accurate curves of samples containing open vessels, supporting the validity of this technique and confirming its utility in understanding plant hydraulics. Seven recommendations for avoiding artefacts and standardizing vulnerability curve methodology are provided. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  2. Flow and separation in gas centrifuge with Beams type circulation

    International Nuclear Information System (INIS)

    Ajsen, Eh.M.; Borisevich, V.D.; Levin, E.V.

    1992-01-01

    Structure of the secondary circulation flows in the working chamber of gas centrifuge for uranium isotope separation is studied using the numerical methods. Influence of the circulation thermal component on the centrifuge efficiency is analyzed. The contribution of useful component concentration difference of binary isotope mixture in feeding flows to the centrifuge efficiency is determined. Dependence of concentration optimal difference, whereby the maximum efficiency is achieved, on temperature distribution on the rotor side wall is found

  3. Partial suppression of the respiratory defect of qrs1/her2 glutamyl-tRNA amidotransferase mutants by overexpression of the mitochondrial pentatricopeptide Msc6p.

    Science.gov (United States)

    Moda, Bruno S; Ferreira-Júnior, José Ribamar; Barros, Mario H

    2016-08-01

    Recently, a large body of evidences indicates the existence in the mitochondrial matrix of foci that contain different proteins involved in mitochondrial RNA metabolism. Some of these proteins have a pentatricopeptide repeat motif that constitutes their RNA-binding structures. Here we report that MSC6, a mitochondrial pentatricopeptide protein of unknown function, is a multi copy suppressor of mutations in QRS1/HER2 a component of the trimeric complex that catalyzes the transamidation of glutamyl-tRNAQ to glutaminyl-tRNAQ. This is an essential step in mitochondrial translation because of the lack of a specific mitochondrial aminoacyl glutaminyl-tRNA synthetase. MSC6 over-expression did not abolish translation of an aberrant variant form of Cox2p detected in QRS1/HER2 mutants, arguing against a suppression mechanism that bypasses Qrs1p function. A slight decrement of the mitochondrial translation capacity as well as diminished growth on respiratory carbon sources media for respiratory activity was observed in the msc6 null mutant. Additionally, the msc6 null mutant did not display any impairment in RNA transcription, processing or turnover. We concluded that Msc6p is a mitochondrial matrix protein and further studies are required to indicate the specific function of Msc6p in mitochondrial translation.

  4. Effect of centrifugation on dynamic susceptibility of magnetic fluids

    International Nuclear Information System (INIS)

    Pshenichnikov, Alexander; Lebedev, Alexander; Lakhtina, Ekaterina; Kuznetsov, Andrey

    2017-01-01

    Highlights: • Six samples of magnetic fluid were obtained by centrifuging two base ferrocolloids. • Aggregates in magnetic fluids are main reason of dynamic susceptibility dispersion. • Centrifugation is an effective way of changing the dynamic susceptibility. - Abstract: The dispersive composition, dynamic susceptibility and spectrum of times of magnetization relaxation for six samples of magnetic fluid obtained by centrifuging two base colloidal solutions of the magnetite in kerosene was investigated experimentally. The base solutions differed by the concentration of the magnetic phase and the width of the particle size distribution. The procedure of cluster analysis allowing one to estimate the characteristic sizes of aggregates with uncompensated magnetic moments was described. The results of the magnetogranulometric and cluster analyses were discussed. It was shown that centrifugation has a strong effect on the physical properties of the separated fractions, which is related to the spatial redistribution of particles and multi-particle aggregates. The presence of aggregates in magnetic fluids is interpreted as the main reason of low-frequency (0.1–10 kHz) dispersion of the dynamic susceptibility. The obtained results count in favor of using centrifugation as an effective means of changing the dynamic susceptibility over wide limits and obtaining fluids with the specified type of susceptibility dispersion.

  5. Effect of centrifugation on dynamic susceptibility of magnetic fluids

    Energy Technology Data Exchange (ETDEWEB)

    Pshenichnikov, Alexander, E-mail: pshenichnikov@icmm.ru; Lebedev, Alexander; Lakhtina, Ekaterina; Kuznetsov, Andrey

    2017-06-15

    Highlights: • Six samples of magnetic fluid were obtained by centrifuging two base ferrocolloids. • Aggregates in magnetic fluids are main reason of dynamic susceptibility dispersion. • Centrifugation is an effective way of changing the dynamic susceptibility. - Abstract: The dispersive composition, dynamic susceptibility and spectrum of times of magnetization relaxation for six samples of magnetic fluid obtained by centrifuging two base colloidal solutions of the magnetite in kerosene was investigated experimentally. The base solutions differed by the concentration of the magnetic phase and the width of the particle size distribution. The procedure of cluster analysis allowing one to estimate the characteristic sizes of aggregates with uncompensated magnetic moments was described. The results of the magnetogranulometric and cluster analyses were discussed. It was shown that centrifugation has a strong effect on the physical properties of the separated fractions, which is related to the spatial redistribution of particles and multi-particle aggregates. The presence of aggregates in magnetic fluids is interpreted as the main reason of low-frequency (0.1–10 kHz) dispersion of the dynamic susceptibility. The obtained results count in favor of using centrifugation as an effective means of changing the dynamic susceptibility over wide limits and obtaining fluids with the specified type of susceptibility dispersion.

  6. A comparison of two centrifuge techniques for constructing vulnerability curves: insight into the 'open-vessel' artifact.

    Science.gov (United States)

    Yin, Pengxian; Meng, Feng; Liu, Qing; An, Rui; Cai, Jing; Du, Guangyuan

    2018-03-30

    A vulnerability curve (VC) describes the extent of xylem cavitation resistance. Centrifuges have been used to generate VCs for decades via static- and flow-centrifuge methods. Recently, the validity of the centrifuge techniques has been questioned. Researchers have hypothesized that the centrifuge techniques might yield unreliable VCs due to the open-vessel artifact. However, other researchers reject this hypothesis. The focus of the dispute is centred on whether exponential VCs are more reliable when the static-centrifuge method is used than with the flow-centrifuge method. To further test the reliability of the centrifuge technique, two centrifuges were manufactured to simulate the static- and flow-centrifuge methods. VCs of three species with open vessels of known lengths were constructed using the two centrifuges. The results showed that both centrifuge techniques produced invalid VCs for Robinia because the water flow through stems under mild tension in centrifuges led to an increasing loss of water conductivity. Additionally, the injection of water in the flow-centrifuge exacerbated the loss of water conductivity. However, both centrifuge techniques yielded reliable VCs for Prunus, regardless of the presence of open vessels in the tested samples. We conclude that centrifuge techniques can be used in species with open vessels only when the centrifuge produces a VC that matches the bench-dehydration VC. This article is protected by copyright. All rights reserved.

  7. Centar's gas centrifuge enrichment project

    International Nuclear Information System (INIS)

    Abajian, V.V.; Fishman, A.M.

    1976-01-01

    Plans for the building and operating of Centar Associates gas centrifuge uranium enrichment plant are described. Operating costs and machine manufacture are considered. Commitments with the utilities are summarised. (U.K.)

  8. Annular centrifugal contactors for TRPO process test

    International Nuclear Information System (INIS)

    Duan, W.H.; Wang, J.C.; Chen, J.; Zhou, X.Z.; Zhou, J.Z.; Song, C.L.

    2005-01-01

    The TRPO process has been developed in China for removing TRU elements from high-level liquid waste (HLLW) since 1980s. Centrifugal contactors have several advantages such as low hold-up volume, short residence time, low solvent degradation, small space requirements and short start-up time. Therefore, they are favored for both the reprocessing of spent fuel and the treatment of HLLW. In order to meet study on the TRPO test, a series of annular centrifugal contactors have been developed in Institute of Nuclear and -New Energy Technology, Tsinghua University, China (INET). In particular, the 10-mm annular centrifugal contactor for the laboratory-scale test has been applied successfully in the cold and hot tests of the TRPO process. The 70-mm annular centrifugal contactor for the industry-scale test has two new design characteristics, namely a modular design and an overflow structure. The modular design makes the contactor to be disassembled and assembled fast by simply moving the modules up and down. With the overflow structure, even though one stage or non-adjacent stages of the multi-stage cascade in operation are ceased to work, the cascade can continue to operate. Both the hydraulic performance and the mass-transfer efficiency of these contactors are excellent, and the extraction stage efficiency is greater than 95% at suitable operating conditions.

  9. Effect of sludge behavior on performance of centrifugal contactor

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, A.; Sano, Y.; Takeuchi, M. [Japan Atomic Energy Agency - JAEA, 4-33 Muramatsu Tokai-mura Naka-gun Ibaraki-pref. 319-1194 (Japan)

    2016-07-01

    The Japan Atomic Energy Agency has been developing an annular centrifugal contactor for solvent extraction in spent fuel reprocessing, which allows the mixing of aqueous and organic phases in the annular area and their separation from the mixed phase in the rotor. The effects of sludge behavior on the performance of a centrifugal contactor were investigated. Sludge accumulation during the operation of the centrifugal contactor was observed only in the rotor. Based on the sludge accumulation behavior, the effects of rotor sludge accumulation on the performance of phase separation and extraction were investigated using several types of rotors, which simulated different sludge accumulation levels in the separation area. It was confirmed that rotor sludge accumulation would affect the phase separation performance but not the extraction performance. This can be explained by the structure of the centrifugal contactor, wherein the extraction reaction and phase separation mainly proceed in the housing and rotor, respectively.

  10. Return to Flying Duties Following Centrifuge or Vibration Exposures

    Science.gov (United States)

    Scheuring, Richard A.; Clarke, Jonathan; Jones, Jeffrey A.

    2009-01-01

    Introduction: In an effort to determine the human performance limits for vibration in spacecraft being developed by NASA, astronauts were evaluated during a simulated launch profile in a centrifuge/vibration environment and separate vibration-only simulation. Current USAF and Army standards for return to flight following centrifuge exposures require 12-24 hours to pass before a crewmember may return to flying duties. There are no standards on vibration exposures and return to flying duties. Based on direct observation and provocative neurological testing of the astronauts, a new standard for return to flying duties following centrifuge and/or vibration exposures was established. Methods: 13 astronaut participants were exposed to simulated launch profiles in a + 3.5 Gx bias centrifuge/vibration environment and separately on a vibration table at the NASA-Ames Research Center. Each subject had complete neurological evaluations pre- and post-exposure for the centrifuge/vibration runs with the NASA neurological function rating scale (NFRS). Subjects who participated in the vibration-only exposures had video oculography performed with provocative maneuvers in addition to the NFRS. NFRS evaluations occurred immediately following each exposure and at 1 hour post-run. Astronauts who remained symptomatic at 1 hour had repeat NFRS performed at 1 hour intervals until the crewmember was asymptomatic. Results: Astronauts in the centrifuge/vibration study averaged a 3-5 point increase in NFRS scores immediately following exposure but returned to baseline 3 hours post-run. Subjects exposed to the vibration-only simulation had a 1-3 point increase following exposure and returned to baseline within 1-2 hours. Pre- and post- vibration exposure video oculography did not reveal any persistent ocular findings with provocative testing 1 hour post-exposure. Discussion: Based on direct observations and objective measurement of neurological function in astronauts following simulated launch

  11. Method and refrigerants for replacing existing refrigerants in centrifugal compressors

    International Nuclear Information System (INIS)

    Kopko, W.L.

    1991-01-01

    This patent describes a method for replacing an existing refrigerant in a centrifugal compressor. It comprises selecting a desired impeller Mach number for the centrifugal compressor; selecting a base refrigerant constituent; combining at least one additive refrigerant constituent with the base refrigerant constituent to form a replacement refrigerant having at least one physical or chemical property different from the existing refrigerant and substantially providing the desired impeller Mach number in the centrifugal compressor; and replacing the existing refrigerant with the replacement refrigerant

  12. Medical incidences during centrifuge training and F-16 flying in the Netherlands

    NARCIS (Netherlands)

    Holewijn, M.

    1996-01-01

    A survey in the NAMC database containing the records of centrifuge runs of candidate and experienced pilots revealed that in 15.1% of the centrifuge training sessions, a run was stopped. The major reasons were motion sickness (31%), fatigue (28%), and arrhythmias (22%). During centrifuge training at

  13. Spectroscopy of molecules in very high rotational states using an optical centrifuge.

    Science.gov (United States)

    Yuan, Liwei; Toro, Carlos; Bell, Mack; Mullin, Amy S

    2011-01-01

    We have developed a high power optical centrifuge for measuring the spectroscopy of molecules in extreme rotational states. The optical centrifuge has a pulse energy that is more than 2 orders of magnitude greater than in earlier instruments. The large pulse energy allows us to drive substantial number densities of molecules to extreme rotational states in order to measure new spectroscopic transitions that are not accessible with traditional methods. Here we demonstrate the use of the optical centrifuge for measuring IR transitions of N2O from states that have been inaccessible until now. In these studies, the optical centrifuge drives N2O molecules into states with J ~ 200 and we use high resolution transient IR probing to measure the appearance of population in states with J = 93-99 that result from collisional cooling of the centrifuged molecules. High resolution Doppler broadened line profile measurements yield information about the rotational and translational energy distributions in the optical centrifuge.

  14. Centrifuge - dewatering of oil sand fluid tailings: phase 2 field-scale test

    Energy Technology Data Exchange (ETDEWEB)

    Seto, Jack T.C. [BGC Engineering Inc (Canada); O' Kane, Mike [O' Kane Consultants Inc (Canada); Donahue, Robert [Applied Geochemical Solutions Engineering (Canada); Lahaie, Rick [Syncrude Canada Ltd (Canada)

    2011-07-01

    In order to reduce the accumulation of oil sand fluid fine tailings (FFT) and to create trafficable surfaces for reclamation, Syncrude Canada Ltd. has been studying several tailings technologies. Centrifuge-dewatering is one such technology. This paper discusses the phase 2 field-scale tests for centrifuge-dewatering of oil sand FFT. In centrifuge-dewatering, FFT is diluted and treated with flocculant, then processed through a centrifuge plant and the high-density underflow is transported to a tailings deposit. This technology has evolved since 2005 from laboratory bench scale tests. More than 10,000 cubic meters of centrifuge cake was treated, produced and transported to ten different deposits over a 12-week period from August to October 2010. The amount of solids in FFT was increased from 30% to 50% by centrifuging. Sampled deposits were tested and instrumented for in situ strength. It can be concluded that the deposits can be strengthened and densified by natural dewatering processes like freeze-thaw action and evaporative drying.

  15. Onsager's pancake approximation for the fluid dynamics of a gas centrifuge

    International Nuclear Information System (INIS)

    Wood, H.G. III; Morton, J.B.

    1980-01-01

    A previously unpublished theory for describing the internal flow in a gas centrifuge is presented. The theory is based on boundary layer type arguments on the side walls of the centrifuge with the additional approximation of neglecting radial diffusion of radial momentum. The effects of the top and bottom end caps are incorporated through Ekman layer solutions. The results are presented in a form amenable to numerical calculations. Some sample calculations are presented for the special case of a centrifuge with a linear temperature profile on the wall and the top and bottom of the centrifuge at the same temperature as the corresponding end of the side wall

  16. Onsager's pancake approximation for the fluid dynamics of a gas centrifuge

    International Nuclear Information System (INIS)

    Wood, H.G.

    1980-01-01

    A previously unpublished theory for describing the internal flow in a gas centrifuge is presented. The theory is based on boundary-layer-type arguments on the side walls of the centrifuge with the additional approximation of neglecting radial diffusion of radial momentum. The effects of the top and bottom end caps are incorporated through Ekman-layer solutions. The results are presented in a form amenable to numerical calculations. Some sample calculations are presented for the special case of a centrifuge with a linear temperature profile on the wall and the top and bottom of the centrifuge at the same temperature as the corresponding end of the side wall. (author)

  17. Preflight screening techniques for centrifuge-simulated suborbital spaceflight.

    Science.gov (United States)

    Pattarini, James M; Blue, Rebecca S; Castleberry, Tarah L; Vanderploeg, James M

    2014-12-01

    Historically, space has been the venue of the healthy individual. With the advent of commercial spaceflight, we face the novel prospect of routinely exposing spaceflight participants (SPFs) with multiple comorbidities to the space environment. Preflight screening procedures must be developed to identify those individuals at increased risk during flight. We examined the responses of volunteers to centrifuge accelerations mimicking commercial suborbital spaceflight profiles to evaluate how potential SFPs might tolerate such forces. We evaluated our screening process for medical approval of subjects for centrifuge participation for applicability to commercial spaceflight operations. All registered subjects completed a medical questionnaire, physical examination, and electrocardiogram. Subjects with identified concerns including cardiopulmonary disease, hypertension, and diabetes were required to provide documentation of their conditions. There were 335 subjects who registered for the study, 124 who completed all prescreening, and 86 subjects who participated in centrifuge trials. Due to prior medical history, five subjects were disqualified, most commonly for psychiatric reasons or uncontrolled medical conditions. Of the subjects approved, four individuals experienced abnormal physiological responses to centrifuge profiles, including one back strain and three with anxiety reactions. The screening methods used were judged to be sufficient to identify individuals physically capable of tolerating simulated suborbital flight. Improved methods will be needed to identify susceptibility to anxiety reactions. While severe or uncontrolled disease was excluded, many subjects successfully participated in centrifuge trials despite medical histories of disease that are disqualifying under historical spaceflight screening regimes. Such screening techniques are applicable for use in future commercial spaceflight operations.

  18. An experiment to test centrifugal confinement for fusion

    International Nuclear Information System (INIS)

    Ellis, R.F.; Hassam, A.B.; Messer, S.; Osborn, B.R.

    2001-01-01

    The basic idea of centrifugal confinement is to use centrifugal forces from supersonic rotation to augment conventional magnetic confinement. Optimizing this 'knob' results in a fusion device that features four advantages: steady state, no disruptions, superior cross-field confinement, and a simpler coil configuration. The idea rests on two prongs: first, centrifugal forces can confine plasmas to desired regions of shaped magnetic fields; second, the accompanying large velocity shear can stabilize even magnetohydrodynamic (MHD) instabilities. A third feature is that the velocity shear also viscously heats the plasma; no auxiliary heating is necessary to reach fusion temperatures. Regarding transport, the velocity shear can also quell microturbulence, leading to fully classical confinement, as there are no neoclassical effects. Classical parallel electron transport then sets the confinement time. These losses are minimized by a large Pastukhov factor resulting from the deep centrifugal potential well: at Mach 4-5, the Lawson criterion is accessible. One key issue is whether velocity shear will be sufficient by itself to stabilize MHD interchanges. Numerical simulations indicate that laminar equilibria can be obtained at Mach numbers of 4-5 but that the progression toward laminarity with increasing Mach number is accompanied by residual convection from the interchanges. The central goal of the Maryland Centrifugal Torus (MCT) [R. F. Ellis et al., Bull. Am. Phys. Soc. 44, 48 (1998)] is to obtain MHD stability from velocity shear. As an assist to accessing laminarity, MCT will incorporate two unique features: plasma elongation and toroidal magnetic field. The former raises velocity shear efficiency, and modest magnetic shear should suppress residual convection

  19. Environmental applications of the centrifugal fast analyzer

    International Nuclear Information System (INIS)

    Goldstein, G.; Strain, J.E.; Bowling, J.L.

    1975-12-01

    The centrifugal fast analyzer (GeMSAEC Fast Analyzer) was applied to the analysis of pollutants in air and water. Since data acquisition and processing are computer controlled, considerable effort went into devising appropriate software. A modified version of the standard FOCAL interpreter was developed which includes special machine language functions for data timing, acquisition, and storage, and also permits chaining together of programs stored on a disk. Programs were written and experimental procedures developed to implement spectrophotometric, turbidimetric, kinetic (including initial-rate, fixed-time, and variable-time techniques), and chemiluminescence methods of analysis. Analytical methods were developed for the following elements and compounds: SO 2 , O 3 , Ca, Cr, Cu, Fe, Mg, Se(IV), Zn, Cl - , I - , NO 2 - , PO 4 -3 , S -2 , and SO 4 -2 . In many cases, standard methods could be adapted to the centrifugal analyzer, in others new methods were employed. In general, analyses performed with the centrifugal fast analyzer were faster, more precise, and more accurate than with conventional instrumentation

  20. Influence of centrifuge brake on residual platelet count and routine coagulation tests in citrated plasma.

    Science.gov (United States)

    Daves, Massimo; Giacomuzzi, Katia; Tagnin, Enrico; Jani, Erika; Adcock Funk, Dorothy M; Favaloro, Emmanuel J; Lippi, Giuseppe

    2014-04-01

    Sample centrifugation is an essential step in the coagulation laboratory, as clotting tests are typically performed on citrated platelet (PLT) poor plasma (PPP). Nevertheless, no clear indication has been provided as to whether centrifugation of specimens should be performed with the centrifuge brake set to on or off. Fifty consecutive sodium citrate anticoagulated samples were collected and divided into two aliquots. The former was centrifuged as for Clinical Laboratory Standards Institute (CLSI) guidelines with the centrifuge brake set to on, whereas the latter was centrifuged again as for CLSI guidelines, but with the brake set to off. In the PPP of all samples, a PLT count was performed, followed by the analysis of activated partial thromboplastin time (APTT), prothrombin time (PT) and fibrinogen (FBG). The PLT count after samples centrifugation was substantially reduced, either with centrifuge brake set to on or off (5 ± 1 versus 3 ± 1 × 10/l; P = 0.009). The frequency of samples exceeding a PLT count less than 10 × 10/l was nearly double in samples centrifuged with the brake on than in those with the brake off (14 versus 8%; P centrifuge brake set to on (mean bias 0.2 s; P centrifuge brake set to on (mean bias 0.29 g/l; P centrifugation for routine coagulation testing should be preferably performed with the centrifuge brake set to off for providing a better quality specimen.

  1. Lightweight Shield for Centrifuge

    Science.gov (United States)

    Luper, C.

    1982-01-01

    Centrifuge bowl composed of laminated aluminum offers required combination of high strength at reduced weight. Around outside wall of bowl core of 1/16 inch thick spun aluminum are wrapped two layers of aluminum, each also one-sixteenth inch thick. Layered structure prevents cracks from propagating through wall.

  2. Fluid dynamic interaction between water hammer and centrifugal pumps

    International Nuclear Information System (INIS)

    Ismaier, A.; Schluecker, E.

    2009-01-01

    Centrifugal pumps generate in piping systems noticeable pressure pulsations. In this paper the dynamic interaction between water hammer and pressure pulsations is presented. The experimental investigations were performed at a piping system with nominal diameter DN 100 (respectively NPS 4) and 75 m total length, built at the Institute for Process Technology and Machinery. Different measurements at this testing facility show that pulsating centrifugal pumps can damp pressure surges generated by fast valve closing. It is also shown that 1-dimensional fluid codes can be used to calculate this phenomenon. Furthermore it is presented that pressure surges pass centrifugal pumps almost unhindered, because they are hydraulic open.

  3. Numerical optimization for separation power of gas centrifuge

    International Nuclear Information System (INIS)

    Jiang Dongjun; Zeng Shi; Liu Bing

    2012-01-01

    In order to obtain higher separation power of the gas centrifuge, the code was developed to solve the flow-field of the counter-current to acquire the separation power, which was integrated with the iSight software, so a numerical optimization model for separation power was presented, in which the driver conditions and the geometry parameters of the waste baffle were optimized to get the maximum separation power using the sequential quadratic programming arithmetic, and the 12% higher results was acquired, which shows the feasibility of this method. The results also note that the separation power of gas centrifuge is sensitive to the driver conditions and the structure parameters of the waste baffle, so it is necessary to perform the optimization calculation for the certain gas centrifuge model. (authors)

  4. Wave-Driven Rotation In Centrifugal Mirrors

    International Nuclear Information System (INIS)

    Fetterman, Abraham J.; Fisch, Nathaniel J.

    2011-01-01

    Centrifugal mirrors use supersonic rotation to provide axial confinement and enhanced stability. Usually the rotation is produced using electrodes, but these electrodes have limited the rotation to the Alfven critical ionization velocity, which is too slow to be useful for fusion. Instead, the rotation could be produced using radio frequency waves. A fixed azimuthal ripple is a simple and efficient wave that could produce rotation by harnessing alpha particle energy. This is an extension of the alpha channeling effect. The alpha particle power and efficiency in a simulated devices is sufficient to produce rotation without external energy input. By eliminating the need for electrodes, this opens new opportunities for centrifugal traps.

  5. Effects of different centrifugation conditions on clinical chemistry and Immunology test results

    Directory of Open Access Journals (Sweden)

    Nesic Predrag

    2011-05-01

    Full Text Available Abstract Background The effect of centrifugation time of heparinized blood samples on clinical chemistry and immunology results has rarely been studied. WHO guideline proposed a 15 min centrifugation time without citing any scientific publications. The centrifugation time has a considerable impact on the turn-around-time. Methods We investigated 74 parameters in samples from 44 patients on a Roche Cobas 6000 system, to see whether there was a statistical significant difference in the test results among specimens centrifuged at 2180 g for 15 min, at 2180 g for 10 min or at 1870 g for 7 min, respectively. Two tubes with different plasma separators (both Greiner Bio-One were used for each centrifugation condition. Statistical comparisons were made by Deming fit. Results Tubes with different separators showed identical results in all parameters. Likewise, excellent correlations were found among tubes to which different centrifugation conditions were applied. Fifty percent of the slopes lay between 0.99 and 1.01. Only 3.6 percent of the statistical tests results fell outside the significance level of p Conclusion A centrifugation time of either 7 or 10 min provided identical test results compared to the time of 15 min as proposed by WHO under the conditions used in our study.

  6. Simulating of single phase flow in typical centrifugal pumps oil industry; Simulacao do escoamento monofasico em bombas centrifugas tipicas da industria do petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Ana Carla Costa; Silva, Aldrey Luis Morais da; Maitelli, Carla Wilza Souza de Paula [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil)

    2012-07-01

    With the various techniques applied in production processes and oil exploration, has been using the artificial lift equipment with the aim of promoting an increase in flow in oil wells and gas. Choosing the most appropriate method of elevation depends on certain factors, among them the initial costs of installation, maintenance and conditions in the producing field, resulting in a more precise analysis of the project. Although there are other methods that represent a low cost and easy maintenance, the BCS method (Electrical Submersible Pumping), appears to be quite effective when it is intended to pump more flow of liquids from both terrestrial and marine environments, in conditions adverse temperature, presence of free gas in the mixture and viscous fluids. This method is based in most cases where the vessel pressure was low, and the fluid does not reach the surface without intervention of an artificial means which can lift them. Similar happens at the end of productive life of a resurgence for the well, or even when the flow of it is far below what is expected to produce, requiring a complement of natural energy through artificial lift. By definition, the BCS is a method of artificial lift in which a subsurface electric motor turns electrical energy into mechanical centrifugal pump and a multistage overlapping converts mechanical energy into kinetic energy of the engine bringing the fluid surface. In this study we performed computer simulations using a commercial program ANSYS #Registered Sign# CFX #Registered Sign# dimensions previously obtained by the 3D geometry in CAD format, with the objective of evaluating the single-phase flow inside typical centrifugal pump submerged in the oil industry. The variable measured was the height of elevation and drilling fluids are oil and water.(author)

  7. Droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling for simpler and faster PCR assay using wire-guided manipulations.

    Science.gov (United States)

    You, David J; Yoon, Jeong-Yeol

    2012-09-04

    A computer numerical control (CNC) apparatus was used to perform droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling on a single superhydrophobic surface and a multi-chambered PCB heater. Droplets were manipulated using "wire-guided" method (a pipette tip was used in this study). This methodology can be easily adapted to existing commercial robotic pipetting system, while demonstrated added capabilities such as vibrational mixing, high-speed centrifuging of droplets, simple DNA extraction utilizing the hydrophobicity difference between the tip and the superhydrophobic surface, and rapid thermocycling with a moving droplet, all with wire-guided droplet manipulations on a superhydrophobic surface and a multi-chambered PCB heater (i.e., not on a 96-well plate). Serial dilutions were demonstrated for diluting sample matrix. Centrifuging was demonstrated by rotating a 10 μL droplet at 2300 round per minute, concentrating E. coli by more than 3-fold within 3 min. DNA extraction was demonstrated from E. coli sample utilizing the disposable pipette tip to cleverly attract the extracted DNA from the droplet residing on a superhydrophobic surface, which took less than 10 min. Following extraction, the 1500 bp sequence of Peptidase D from E. coli was amplified using rapid droplet thermocycling, which took 10 min for 30 cycles. The total assay time was 23 min, including droplet centrifugation, droplet DNA extraction and rapid droplet thermocycling. Evaporation from of 10 μL droplets was not significant during these procedures, since the longest time exposure to air and the vibrations was less than 5 min (during DNA extraction). The results of these sequentially executed processes were analyzed using gel electrophoresis. Thus, this work demonstrates the adaptability of the system to replace many common laboratory tasks on a single platform (through re-programmability), in rapid succession (using droplets), and with a high level of

  8. Structural Investigation of MscL Gating Using Experimental Data and Coarse Grained MD Simulations

    NARCIS (Netherlands)

    Deplazes, Evelyne; Louhivuori, Martti; Jayatilaka, Dylan; Marrink, Siewert J.; Corry, Ben

    The mechanosensitive channel of large conductance (MscL) has become a model system in which to understand mechanosensation, a process involved in osmoregulation and many other physiological functions. While a high resolution closed state structure is available, details of the open structure and the

  9. A 4-spot time-of-flight anemometer for small centrifugal compressor velocity measurements

    Science.gov (United States)

    Wernet, Mark P.; Skoch, Gary J.

    1992-01-01

    The application of laser anemometry techniques in turbomachinery facilities is a challenging dilemma requiring an anemometer system with special qualities. Here, we describe the use of a novel laser anemometry technique applied to a small 4.5 kg/s, 4:1 pressure ratio centrifugal compressor. Sample velocity profiles across the blade pitch are presented for a single location along the rotor. The results of the intra-blade passage velocity measurements will ultimately be used to verify CFD 3-D viscous code predictions.

  10. A ‘smart’ tube holder enables real-time sample monitoring in a standard lab centrifuge

    Science.gov (United States)

    Hoang, Tony; Moskwa, Nicholas

    2018-01-01

    The centrifuge is among the oldest and most widely used pieces of laboratory equipment, with significant applications that include clinical diagnostics and biomedical research. A major limitation of laboratory centrifuges is their “black box” nature, limiting sample observation to before and after centrifugation. Thus, optimized protocols require significant trial and error, while unoptimized protocols waste time by centrifuging longer than necessary or material due to incomplete sedimentation. Here, we developed an instrumented centrifuge tube receptacle compatible with several commercial benchtop centrifuges that can provide real-time sample analysis during centrifugation. We demonstrated the system by monitoring cell separations during centrifugation for different spin speeds, concentrations, buffers, cell types, and temperatures. We show that the collected data are valuable for analytical purposes (e.g. quality control), or as feedback to the user or the instrument. For the latter, we verified an adaptation where complete sedimentation turned off the centrifuge and notified the user by a text message. Our system adds new functionality to existing laboratory centrifuges, saving users time and providing useful feedback. This add-on potentially enables new analytical applications for an instrument that has remained largely unchanged for decades. PMID:29659624

  11. Implementation of centrifuge testing of expansive soils for pavement design.

    Science.gov (United States)

    2017-03-01

    The novel centrifuge-based method for testing of expansive soils from project 5-6048-01 was implemented into : use for the determination of the Potential Vertical Rise (PVR) of roadways that sit on expansive subgrades. The : centrifuge method was mod...

  12. Centrifugal compressor design options for small turbochargers

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, C. [ITC, San Diego (United States)

    1998-07-01

    Evolutionary development of the small turbocharger centrifugal compressor over the past four decades has resulted in a finely honed turbomachinery component satisfying both thermodynamic and economic constraints. At this penultimate stage of development an appraisal was considered timely of the remaining design options that exist to enhance the performance characteristics and cost reduction features. This paper presents the results of an analytical study of various small centrifugal compressor design options, assessed in merit of both aerodynamic and manufacturing cost attributes, together with recommendations for future research avenues. (author)

  13. Numerical analysis on centrifugal compressor with membrane type dryer

    Science.gov (United States)

    Razali, M. A.; Zulkafli, M. F.; Mat Isa, N.; Subari, Z.

    2017-09-01

    Moisture content is a common phenomenon in industrial processes especially in oil and gas industries. This contaminant has a lot of disadvantages which can lead to mechanical failure DEC (Deposition, Erosion & Corrosion) problems. To overcome DEC problem, this study proposed to design a centrifugal compressor with a membrane type dryer to reduce moisture content of a gas. The effectiveness of such design has been analyzed in this study using Computational Fluid Dynamics (CFD) approach. Numerical scheme based on multiphase flow technique is used in ANSYS Fluent software to evaluate the moisture content of the gas. Through this technique, two kind of centrifugal compressor, with and without membrane type dryer has been tested. The results show that the effects of pressure on dew point temperature of the gas change the composition of its moisture content, where high value lead more condensation to occur. However, with the injection of cool dry gas through membrane type dryer in the centrifugal compressor, the pressure and temperature of moisture content as well as mass fraction of H2O in centrifugal compressor show significant reduction.

  14. Plasma rotation in plasma centrifuge with an annular gap

    International Nuclear Information System (INIS)

    Lee, H.Y.; Hong, S.H.

    1982-01-01

    The steady-state rotation of plasma centrifuge is theoretically analyzed to understand the physics of rotating plasma and its feasibility for isotope separation. The centriguge system under consideration consists of an annular gap between coaxial cylindrical anode and cathod in the presence of an externally-applied axial magnetic field. A problem for coupled partial differential equations describing centrifuge fields is formulated on the basis of the magnetohydrodynamic equations. Two-dimensional solutions are found analytically in the form of Fourier-Bessel series. The current density and velocity distributions are discussed in terms of the Hartmann number and the geometrical parameter of the system. At typical conditions, rotational speeds of the plasma up to the order of 10 4 m/sec are achievable, and increase either with increasing Hartmann number, or with increasing ratio of the axial length to the inner radius of the cylinder. In view of much higher speeds of rotation which can be achieved in plasma centrifuge, it is expected that its efficiency is superior to mechanically driven gas centrifuges. (Author)

  15. The effect of balance holes to centrifugal pump performance

    Science.gov (United States)

    Babayigit, O.; Ozgoren, M.; Aksoy, M. H.; Kocaaslan, O.

    2017-07-01

    The aim of this study is to analyze of a centrifugal pump with and without balance holes by using ANSYS-Fluent software. The pump used in the study is a commercial centrifugal pump consisting of two stages that is a model of Sempa Pump Company. Firstly, models of impeller, diffuser, suction and discharge sections of the centrifugal pump were separately drawn using Ansys and Solidworks software. Later, grid structures were generated on the flow volume of the pump. Turbulent flow volume was numerically solved by realizable k-є turbulence model. The flow analyses were focused on the centrifugal pump performance and the flow characteristics under different operational conditions with/without balance holes. Distributions of flow characteristics such as velocity and pressure distributions in the flow volume were also determined, numerically. The results of Computational Fluid Dynamics (CFD) with/without balance holes for the pump head and hydraulic efficiency on the design flow rate of 80 m3/h were found to be 81.5/91.3 m and 51.9/65.3%, respectively.

  16. Design of a high-performance centrifugal compressor with new surge margin improvement technique for high speed turbomachinery

    Directory of Open Access Journals (Sweden)

    Sagar Pakle

    2018-03-01

    Full Text Available This paper presents the design of a centrifugal compressor for high-speed turbomachinery. The main focus of the research is to develop a centrifugal compressor with improved aerodynamic performance. As a meridional frame has a significant effect on overall performance of the compressor, special attention has been paid to the end wall contours. The shroud profile is design with bezier curve and hub profile with circular arc contour. The blade angle distribution has been arranged in a manner that it merges with single value at impeller exit. The rake angle is positive at leading edge and negative at trailing edge with identical magnitude. Furthermore, three-dimensional straight line element approach has been used for this design for better manufacturability. The verification of the aerodynamic performance has been carried out using CFD software with consideration of a single blade passage and vaneless diffuser. The result has been compared with matching size aftermarket compressor stage gas stand data. The compressor stage with Trim 55 provides 34% increase in choke flow at 210000 RPM as compared to gas stand data with 87% peak stage efficiency at 110000 RPM. In addition, new surge margin improvement technique has been proposed by means of diffuser enhancement. This technique provides an average of 16% improvement in surge margin compared to standard diffuser stage with 55 trim compressor impeller. The mechanical integrity has been validated at maximum RPM with the aluminum alloy 2014-T6 as a fabrication material. Keywords: Centrifugal compressor, Aerodynamic performance, Surge margin, Blade angles, Stress analysis, Computational fluid dynamics

  17. The Maryland Centrifugal Experiment (MCX): Centrifugal Confinement and Velocity Shear Stabilization of Plasmas in Shaped Open Magnetic Systems

    International Nuclear Information System (INIS)

    Hassam, Adil; Ellis, Richard F.

    2012-01-01

    The Maryland Centrifugal Experiment (MCX) Project has investigated the concepts of centrifugal plasma confinement and stabilization of instabilities by velocity shear. The basic requirement is supersonic plasma rotation about a shaped, open magnetic field. Overall, the MCX Project attained three primary goals that were set out at the start of the project. First, supersonic rotation at Mach number up to 2.5 was obtained. Second, turbulence from flute interchange modes was found considerably reduced from conventional. Third, plasma pressure was contained along the field, as evidenced by density drops of x10 from the center to the mirror throats.

  18. Modeling industrial centrifugation of mammalian cell culture using a capillary based scale-down system.

    Science.gov (United States)

    Westoby, Matthew; Rogers, Jameson K; Haverstock, Ryan; Romero, Jonathan; Pieracci, John

    2011-05-01

    Continuous-flow centrifugation is widely utilized as the primary clarification step in the recovery of biopharmaceuticals from cell culture. However, it is a challenging operation to develop and characterize due to the lack of easy to use, small-scale, systems that can be used to model industrial processes. As a result, pilot-scale continuous centrifugation is typically employed to model large-scale systems requiring a significant amount of resources. In an effort to reduce resource requirements and create a system which is easy to construct and utilize, a capillary shear device, capable of producing energy dissipation rates equivalent to those present in the feed zones of industrial disk stack centrifuges, was developed and evaluated. When coupled to a bench-top, batch centrifuge, the capillary device reduced centrate turbidity prediction error from 37% to 4% compared to using a bench-top centrifuge alone. Laboratory-scale parameters that are analogous to those routinely varied during industrial-scale continuous centrifugation were identified and evaluated for their utility in emulating disk stack centrifuge performance. The resulting relationships enable bench-scale process modeling of continuous disk stack centrifuges using an easily constructed, scalable, capillary shear device coupled to a typical bench-top centrifuge. Copyright © 2010 Wiley Periodicals, Inc.

  19. Detection of outliers in a gas centrifuge experimental data

    Directory of Open Access Journals (Sweden)

    M. C. V. Andrade

    2005-09-01

    Full Text Available Isotope separation with a gas centrifuge is a very complex process. Development and optimization of a gas centrifuge requires experimentation. These data contain experimental errors, and like other experimental data, there may be some gross errors, also known as outliers. The detection of outliers in gas centrifuge experimental data is quite complicated because there is not enough repetition for precise statistical determination and the physical equations may be applied only to control of the mass flow. Moreover, the concentrations are poorly predicted by phenomenological models. This paper presents the application of a three-layer feed-forward neural network to the detection of outliers in analysis of performed on a very extensive experiment.

  20. Platelet concentration of plateletrich plasma from dogs, obtained through three centrifugation speeds

    Directory of Open Access Journals (Sweden)

    Vanessa Couto de Magalhães Ferraz

    2007-12-01

    Full Text Available The platelets release at least 4 growth factors (Platelet Derived Growth Factor. ²1 and ²2 Transforming Growth Factors and Insulin-like Growth Factor which are responsible for the migration and activation of cells that will start the reparation of soft tissues and bones. The Platelet Rich Plasma is an autogenous source for Growth Factors, obtained by platelet concentration by centrifuging total blood. This study aimed the comparison of platelet concentrations in plasma centrifuged in three different centrifugation speeds (1300, 1600 e 3200rpm, for the production of platelet rich plasma. Blood was drowned from 15 dogs, 40ml of each, and these were divided into four groups and centrifuged at 800rpm. Then the first group was centrifuged at 1300rpm, the second at 1600rpm, the third at 3200rpm and the last was used as control, named plasma. The mean percentage increase in the platelet concentration for each technique was: 1300 - 183%, 1600 - 210% and 3200 - 222%. But in centrifugation at 3200 rpm, platelets presented altered morphology and different sizes in every sample studied, which was understood as severe cell damage. It was concluded that the best technique for the preparation of the platelet rich plasma in dogs consisted of the previous centrifugation of the blood at 800rpm for ten minutes, and then the plasma should be separated. This plasma is then submitted to a second centrifugation of 1600rpm for 10 minutes, and the platelet poor plasma is separated and discharged.

  1. Guided imagery, anxiety, heart rate, and heart rate variability during centrifuge training.

    Science.gov (United States)

    Jing, Xiaolu; Wu, Ping; Liu, Fang; Wu, Bin; Miao, Danmin

    2011-02-01

    Centrifuge training is an important method of improving the hypergravity tolerance of pilots, cosmonauts, and Chinese astronauts. However, the concomitants of tension or anxiety often impede training. Guided imagery (GI), a mind-body relaxation technique, provides a behavioral and cognitive means whereby individuals are able to exert control over the focus of attention. This study aims to investigate the immediate effects of GI for reducing stress in centrifuge training. There were 12 healthy young men who were randomly assigned to a GI group or music group. We measured changes in heart rate during centrifuge training, in heart rate variability before and after centrifuge training, and also evaluated relaxation and anxiety in three phases: before intervention, after intervention, and following centrifuge training. The change in the pattern of anxiety was different in the two groups over the three phases. Anxiety (measured by State Anxiety Inventory) in the GI group changed from 31.7 +/- 5.9 to 26.8 +/- 2.6 and 27.8 +/- 4.1, whereas for the music group this changed from 32.2 +/- 7.6 to 31.2 +/- 8.3 and 26.8 +/- 6.8. During centrifuge training, the maximal HR for the GI group (101.2 +/- 8.8) was lower than that of the music group (123.0 +/- 19.1). In addition GI showed a decrease in low frequency (LF, 0.04-0.15 Hz) components and an increase in high frequency (HF, 0.15-0.4 Hz) components before and after centrifuge training. GI was capable of decreasing tension, anxiety, and sympathetic nervous system activity pre- or post-centrifugation.

  2. Uranium enrichment by centrifuge in Japan

    International Nuclear Information System (INIS)

    Watanabe, T.; Murase, T.

    1977-01-01

    The demand for enriched uranium is on the increase with nuclear power capacity in which the LWR predominates and is estimated to exceed the supply from the present facilities in the world in less than ten years. Therefore, the basic strategy for enriched uranium is investigated on the following three-point long-range program in Japan: 1. To continue negotiations to extend the current allocation by the long-term contract; 2. To seek active participation in international enrichment projects; and 3. To make efforts to develop uranium enrichment technology and to construct inland facilities. On this basis, a vigorous development program of gas centrigue process for industrialization was launched out in 1972 as a national project. Ever since substantial progress in this field has been made and development works have been increased year after year. At present, a concrete plan of a pilot plant is taking shape. Up to now, several types of centrifuges were developed, of which some were completed as prototype models, and subjected to life tests and also to extensive earthquake-resistivity tests for the characteristics of Japanese geological condition. An enrichment plant is composed of so many centrifuges that the installation and piping system of centrifuges is an important factor which has an effect on plant economy and reliability. Two types of the experimental cascade were constructed in Japan. One has been in operation since 1973, and the other since 1975. Valuable empirical data have been accumulated on cascade characteristics, maintenance scheme and so on. It will be important for the coming plants to have a flexibility to escalation of labor and energy cost, or to variation of the separative work requirement and further. An economic prospect of centrifuge enrichment process is presented

  3. Mechanical loading regulates human MSC differentiation in a multi-layer hydrogel for osteochondral tissue engineering.

    Science.gov (United States)

    Steinmetz, Neven J; Aisenbrey, Elizabeth A; Westbrook, Kristofer K; Qi, H Jerry; Bryant, Stephanie J

    2015-07-01

    A bioinspired multi-layer hydrogel was developed for the encapsulation of human mesenchymal stem cells (hMSCs) as a platform for osteochondral tissue engineering. The spatial presentation of biochemical cues, via incorporation of extracellular matrix analogs, and mechanical cues, via both hydrogel crosslink density and externally applied mechanical loads, were characterized in each layer. A simple sequential photopolymerization method was employed to form stable poly(ethylene glycol)-based hydrogels with a soft cartilage-like layer of chondroitin sulfate and low RGD concentrations, a stiff bone-like layer with high RGD concentrations, and an intermediate interfacial layer. Under a compressive load, the variation in hydrogel stiffness within each layer produced high strains in the soft cartilage-like layer, low strains in the stiff bone-like layer, and moderate strains in the interfacial layer. When hMSC-laden hydrogels were cultured statically in osteochondral differentiation media, the local biochemical and matrix stiffness cues were not sufficient to spatially guide hMSC differentiation after 21 days. However dynamic mechanical stimulation led to differentially high expression of collagens with collagen II in the cartilage-like layer, collagen X in the interfacial layer and collagen I in the bone-like layer and mineral deposits localized to the bone layer. Overall, these findings point to external mechanical stimulation as a potent regulator of hMSC differentiation toward osteochondral cellular phenotypes. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. Quasi-conical centrifugal ion trap

    International Nuclear Information System (INIS)

    Golikov, Yu.K.; Solov'ev, K.V.; Grigor'ev, D.V.; Flegontova, E.Yu.

    1999-01-01

    This paper describes a new excellent ion trap that principally differs from the classic hyperbolic one by its action. The action is based on the axisymmetric electrostatic quasi-conical field with the following potential type: F=F 0 [ln r - r 2 /2+z 2 ], where r, z are cylindrical dimensionless coordinates. The radial potential run (f=ln r-r 2 /2), in this case, is exactly presented by the approximation function f a =ar 2 +b/r 2 +c. In addition, there are some ranges of r (for example, 0.6< r<0.35), in which the concurrence accuracy value is above 0.5%. The paper presents the theory of particles dynamics in the centrifugal trap. Basic correlation for resolution ratios and sensitivity values are developed. Recommendations on the centrifugal trap design implementation, including the recording system, are given

  5. Sludge behavior in centrifugal contactor operation for nuclear fuel reprocessing

    International Nuclear Information System (INIS)

    Sakamoto, Atsushi; Sano, Yuichi; Takeuchi, Masayuki; Okamura, Nobuo; Koizumi, Kenji

    2015-01-01

    The Japan Atomic Energy Agency (JAEA) has been developing the centrifugal contactor for spent fuel reprocessing. In this study, we investigated the sludge behavior in centrifugal contactors at three different scales. The operational conditions (the flow rate and rotor speed) were varied. Most insoluble particles such as sludge remained in the rotor via centrifugal force. The capture ratio of sludge in the contactor was measured as a function of particle size at various flow rates, rotor speeds, and contactor scales. The sludge adhered and accumulated inside the rotor as the operational time increased, and the operational conditions influenced the capture ratio of the sludge; a lower flow rate and higher rotor speed increased the capture ratio. The results confirmed that Stokes' law can be applied to estimate the experimental result on the behavior of the capture ratio for centrifugal contactors with different scales. (author)

  6. Differential centrifugation of leucocytes and platelets applied to 111In-leucocyte labelling

    International Nuclear Information System (INIS)

    Mountford, P.J.

    1986-01-01

    Platelet contamination of 111 In-leucocytes can be minimized by centrifugation of leucocyte-rich plasma before labelling. The differential recovery of leucocytes and platelets from centrifugation depends on various biological and physical factors. Experimental measurements have been made of the effect of some of these factors. The ratio of leucocyte-to-platelet recovery was increased by using more than one centrifugation, and by using a low relative centrifugal force (RCF). To extend the study, a method of calculating cell recovery from centrifugation was developed, based on the experimental results. Calculations indicated that this ratio was at a maximum at around 85g RCF, and was least affected by changes in the suspension medium viscosity. At 85g, leucocyte recovery was incomplete, but calculations indicated that there was a preferential recovery of granulocytes which was subsequently verified by experiment. (author)

  7. Post-MSc technological design (PDEng) traineeships by Dutch universities of technology catalyse industrial innovation

    NARCIS (Netherlands)

    Swinkels, P.L.J.

    2015-01-01

    The two-year post-MSc technological design traineeships organized by the Dutch Universities of Technology, and leading to the Professional Doctorate in Engineering (PDEng) degree, are still going strong after 28 years of existence. In 1986 the Dutch government and the Dutch industry - both aiming to

  8. Instability of a Vacuum Arc Centrifuge

    International Nuclear Information System (INIS)

    Hole, M.J.; Dallaqua, R.S.; Bosco, E. del; Simpson, S.W.

    2003-01-01

    Ever since conception of the Vacuum Arc Centrifuge (VAC) in 1980, periodic fluctuations in the ion saturation current and floating potential have been observed in Langmuir probe measurements in the rotation region of a VAC. Our theoretical and experimental research suggests that these fluctuations are in fact a pressure-gradient driven drift mode. In this work, we summarise the properties of a theoretical model describing the range of instabilities in the VAC plasma column, present theoretical predictions and compare with detailed experiments conducted on the PCEN centrifuge at the Brazilian National Space Research Institute (INPE). We conclude that the observed instability is a 'universal' instability, driven by the density-gradient, in a plasma with finite conductivity

  9. Comparison of fat maintenance in the face with centrifuge versus filtered and washed fat.

    Science.gov (United States)

    Asilian, Ali; Siadat, Amir Hossein; Iraji, Razieh

    2014-06-01

    Autogenous fat injection of the face is a viable and lasting remedy for soft tissue loss and has become a mainstay in facial rejuvenation. Fat transfer as either a stand-alone technique or as an adjunct to other filler technique and lifting depending on patient needs. Although soft tissue augmentation with autologous fat transfer has been increasingly used by esthetic surgeon, but there is no agreement concerning the best way of processing the harvested fat before injection. This study compared the clinical results obtained using simple filtered and washed fat via metal sieve with those achieved by means of pure centrifuged fat. A prospective single-blind analysis on 32 healthy patients undergoing nasolabial fold fat transplantation from 2009 to 2011 (simple sampling). Patients assigned in two groups randomly. The face of half (16 subjects) was injected with centrifuged, another half with simple filtered and washed fat to evaluate the effect of preparation methods on fat graft viability. Objective method was used to evaluate the results, involving the evaluation of postoperative photographs (in month 1, 6 and 12) by an esthetic surgeon (according to the nasolabial scale). Subjective method was a self-assessment obtained from patients about general level of satisfaction and improvement of skin texture, statistical analysis were performed by means of the Wilcoxon and Mann-Whitney test. Acquired data were analyzed using SPSS version 15 and a value of P > 0.05 was considered as significant. There was no significant difference in the survival of grafted fat between the Group 1 (fat-processing with centrifuge at 3400 rpm for 1-min) and Group 2 (washing the fat in the sieve). Our data suggest that the centrifuge of the fat does not enhance survival of grafted fat (P > 0.05).

  10. Centrifugal blood pump 603

    Indian Academy of Sciences (India)

    Centrifugal blood pump 603 pressure obtained for real blood, as shown in figure 6, is a little higher than that for glycerin aqua Solution with the same viscosity as blood. This may indicate the effect of slight non-. Newtonian turbulent flow. The radial whirl motion of the impeller was observed by dual laser position sensors.

  11. Unsteady flow measurements in centrifugal compressors

    International Nuclear Information System (INIS)

    Bammert, K.; Mobarak, A.; Rautenberg, M.

    1976-01-01

    Centrifugal compressors and blowers are often used for recycling the coolant gas in gas-cooled reactors. To achieve the required high pressure ratios, highly loaded centrifugal compressors are built. The paper deals with unsteady flow measurements on highly loaded centrifugal impellers. Measurements of the approaching flow have been done with hot wires. The method of measurement enabled us to get the velocity distribution across the pitch ahead of the inducer. The static pressure signals along the shroud line has been discussed on the basis of some theoretical considerations. Accordingly the form of flow in the impeller and the wave flow or separation zones in the impeller can now be better interpreted. The importance of the unsteady nature of the relative flow, especially at impeller exit, is clearly demonstrated. Measurements with high responsive total pressure probes in the vicinity of impeller exit and the subsequent calculations have shown, that the instantaneous energy transfer at a certain point after the impeller may differ by more than 30% from the Euler work. Lastly, unsteady pressure measurements along the shroud line have been performed during surge and rotating stall. The surge signal have been analyzed in more detail and the mechanism of flow rupture and pressure recovery during a surge cycle is thoroughly discussed. (orig.) [de

  12. A hand-powered, portable, low-cost centrifuge for diagnosing anemia in low-resource settings.

    Science.gov (United States)

    Brown, Jocelyn; Theis, Lauren; Kerr, Lila; Zakhidova, Nazima; O'Connor, Kelly; Uthman, Margaret; Oden, Z Maria; Richards-Kortum, Rebecca

    2011-08-01

    This report describes the development of a hand-powered centrifuge to determine hematocrit values in low-resource settings. A hand-powered centrifuge was constructed by using a salad spinner. Hematocrit values were measured by using the hand-powered device, and results were compared with those of a benchtop centrifuge. The packed cell volume (PCV) measured with the hand-powered device correlated linearly with results obtained with a benchtop centrifuge (r = 0.986, P centrifuge were consistently 1.14 times higher than those measured with the benchtop system. The 14% increase in PCV measured with the hand-powered centrifuge is caused by increased plasma trapped in the cell column. The reader card was adjusted to compensate for trapped plasma. A hand-powered centrifuge and calibrated reader card can be constructed for U.S. $35 and can accurately determine hematocrit values. It is suitable for use in low-resource settings because it is mechanically-powered, inexpensive, and accurate.

  13. Centrifugal shot blast system

    International Nuclear Information System (INIS)

    1998-02-01

    This report describes a demonstration of Concrete cleaning, Inc., modified centrifugal shot blast technology to remove the paint coating from concrete flooring. This demonstration is part of the Chicago Pile-5 (CP-5) Large-Scale Demonstration Project (LSDP) sponsored by the US Department of Energy (DOE), office of Science and Technology (OST), Deactivation and Decommissioning Focus Area (DDFA). The objective of the LSDP is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East (ANL) CP-5 Research Reactor. The purpose of the LSDP is to demonstrate that using innovative and improved decontamination and decommissioning (D and D) technologies from various sources can result in significant benefits, such as decreased cost and increased health and safety, as compared with baseline D and D technologies. Potential markets exist for the innovative centrifugal shot blast system at the following sites: Fernald Environmental Management Project, Los Alamos, Nevada, Oak Ridge Y-12 and K-25, Paducah, Portsmouth Gaseous Diffusion site, and the Savannah River Site. This information is based on a revision to the OST Linkage Tables dated August 4, 1997

  14. Fabrication of silk fibroin film using centrifugal casting technique for corneal tissue engineering.

    Science.gov (United States)

    Lee, Min Chae; Kim, Dong-Kyu; Lee, Ok Joo; Kim, Jung-Ho; Ju, Hyung Woo; Lee, Jung Min; Moon, Bo Mi; Park, Hyun Jung; Kim, Dong Wook; Kim, Su Hyeon; Park, Chan Hum

    2016-04-01

    Films prepared from silk fibroin have shown potential as biomaterials in tissue engineering applications for the eye. Here, we present a novel process for fabrication of silk fibroin films for corneal application. In this work, fabrication of silk fibroin films was simply achieved by centrifugal force. In contrast to the conventional dry casting method, we carried out the new process in a centrifuge with a rotating speed of 4000 rpm, where centrifugal force was imposed on an aluminum tube containing silk fibroin solution. In the present study, we also compared the surface roughness, mechanical properties, transparency, and cell proliferation between centrifugal and dry casting method. In terms of surface morphology, films fabricated by the centrifugal casting have less surface roughness than those by the dry casting. For elasticity and transparency, silk fibroin films obtained from the centrifugal casting had favorable results compared with those prepared by dry casting. Furthermore, primary human corneal keratocytes grew better in films prepared by the centrifugal casting. Therefore, our results suggest that this new fabrication process for silk fibroin films offers important potential benefits for corneal tissue regeneration. © 2015 Wiley Periodicals, Inc.

  15. Designing and analysis study of uranium enrichment with gas centrifuge

    International Nuclear Information System (INIS)

    Tsunetoshi Kai

    2006-01-01

    This note concerns a designing and analysis study of uranium enrichment with a gas centrifuge. At first, one dimensional model is presented and a conventional analytical method is applied to grasp the general idea of a centrifuge performance. Secondly, two-dimensional numerical method is adopted to describe the diffusion phenomena with assumption of simple flow patterns. Parametric surveys are made on the dimension of a centrifuge rotor, the gas feed, withdrawal and circulation system, and operation variables such as feed flow rate, cut and so on. Thirdly, full numerical solutions are obtained for the flow and diffusion equations in static state, using a modified version of the Newton method without neglect of any non-linear term. The numerical results are compared with the experimental data made by Beams et al. and Zippe, and found to be in good agreement. Further, the theoretical pressure and separative power are compared respectively with experimental ones on a comparatively recent centrifuge. The results reveal that the characteristics of separation performance of a centrifuge can be fully described by the present method. Some of inevitable problems are tackled regarding UF 6 gas isotope separation by centrifugation. To examine the influence of the extraneous light gas, the diffusion equations for ternary mixture are solved and also the flow field of binary mixture with large mass difference is obtained to simultaneously solve the Navier-Stokes equations and the diffusion equation.for binary case. Since the gas in the interior region of the rotor is so rarefied that the Navier-Stokes equations cease to be valid, the Burnett equations are solved.for gas flow in a rotating cylinder. Considering that the uranium recovered at a reprocessing plant includes 236 U besides 235 U and 238 U, the concentration distributions of the ternary gas isotopes are determined and a value function is defined for the evaluation of separative work for the multi-component mixture

  16. Research on energy conversion mechanism of a screw centrifugal pump under the water

    International Nuclear Information System (INIS)

    Quan, H; Li, R N; Han, W; Cheng, X R; Shen, Z J; Su, Q M

    2013-01-01

    In order to research screw centrifugal pump impeller power capability and energy conversion mechanism, we used Navier-Stokes equation and standard k-ε equation turbulence model on the basis of the Euler equations to carry out screw centrifugal pump internal flow numerical simulation. This was explored by simulating specific design conditions; the medium is water, variation of speed and pressure of flow filed under the action of the impeller, and the screw centrifugal impeller shroud line and wheel line segment take monitoring sites. The monitoring points are between dynamic head and static head change to analyze the energy conversion capability along the impeller corners of screw centrifugal pump. The results show that the energy of fluid of the screw centrifugal pump is provided by spiral segment, the spiral segment in front of the impeller has played a multi-level role, it has significant reference value to research the energy conversion mechanism of screw centrifugal pump under solid-liquid two phase

  17. Treatment of radio-induced colorectal lesions with Mesenchymal Stromal Cells (MSC): part of the inflammatory process

    International Nuclear Information System (INIS)

    Bessout, R.

    2012-01-01

    Throughout the last decades, radiotherapy established as a major tool in the treatment of abdomino-pelvic cancers. Despite great technological evolutions, radiotherapy remains associated with side effects that can sometimes be really harmful, this being mainly due to the toxicity of ionizing radiations for healthy tissues surrounding the tumor. As part of abdomino-pelvic radio-therapies, these side effects mainly affect the gastrointestinal tract, which is very sensitive to radiations. The development of curative treatments thus became a priority. Mesenchymal stem cells (MSC) showed their immunomodulatory ability as well as their ability to regenerate tissue in many models. During my thesis, we aimed at giving rise to the therapeutic advantage brought by MSC in the treatment of radioinduced damage as well as the underlying molecular mechanisms. Our results allowed us to demonstrate the efficiency of our treatment with an effect both on the colic epithelial structure and on its contractile functions. We demonstrated that this therapeutical efficiency depends on two processes. Stimulation of the epithelial proliferation through the Wnt pathway allows the epithelial regeneration process to be enhanced. The increased local corticosterone secretion allows the number and the activation state of T lymphocytes to diminish. Our results moreover suggest the existence of a link between the two observed phenomenons thus providing with a new proof of the combinatory effects of MSC therapy. (author)

  18. Differential white cell count by centrifugal microfluidics.

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Gregory Jon; Tentori, Augusto M.; Schaff, Ulrich Y.

    2010-07-01

    We present a method for counting white blood cells that is uniquely compatible with centrifugation based microfluidics. Blood is deposited on top of one or more layers of density media within a microfluidic disk. Spinning the disk causes the cell populations within whole blood to settle through the media, reaching an equilibrium based on the density of each cell type. Separation and fluorescence measurement of cell types stained with a DNA dye is demonstrated using this technique. The integrated signal from bands of fluorescent microspheres is shown to be proportional to their initial concentration in suspension. Among the current generation of medical diagnostics are devices based on the principle of centrifuging a CD sized disk functionalized with microfluidics. These portable 'lab on a disk' devices are capable of conducting multiple assays directly from a blood sample, embodied by platforms developed by Gyros, Samsung, and Abaxis. [1,2] However, no centrifugal platform to date includes a differential white blood cell count, which is an important metric complimentary to diagnostic assays. Measuring the differential white blood cell count (the relative fraction of granulocytes, lymphocytes, and monocytes) is a standard medical diagnostic technique useful for identifying sepsis, leukemia, AIDS, radiation exposure, and a host of other conditions that affect the immune system. Several methods exist for measuring the relative white blood cell count including flow cytometry, electrical impedance, and visual identification from a stained drop of blood under a microscope. However, none of these methods is easily incorporated into a centrifugal microfluidic diagnostic platform.

  19. Polymethylmethacrylate/Polyacrylonitrile Membranes via Centrifugal Spinning as Separator in Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Meltem Yanilmaz

    2015-04-01

    Full Text Available Electrospun nanofiber membranes have been extensively studied as separators in Li-ion batteries due to their large porosity, unique pore structure, and high electrolyte uptake. However, the electrospinning process has some serious drawbacks, such as low spinning rate and high production cost. The centrifugal spinning technique can be used as a fast, cost-effective and safe technique to fabricate high-performance fiber-based separators. In this work, polymethylmethacrylate (PMMA/polyacrylonitrile (PAN membranes with different blend ratios were produced via centrifugal spinning and characterized by using different electrochemical techniques for use as separators in Li-ion batteries. Compared with commercial microporous polyolefin membrane, centrifugally-spun PMMA/PAN membranes had larger ionic conductivity, higher electrochemical oxidation limit, and lower interfacial resistance with lithium. Centrifugally-spun PMMA/PAN membrane separators were assembled into Li/LiFePO4 cells and these cells delivered high capacities and exhibited good cycling performance at room temperature. In addition, cells using centrifugally-spun PMMA/PAN membrane separators showed superior C-rate performance compared to those using microporous polypropylene (PP membranes. It is, therefore, demonstrated that centrifugally-spun PMMA/PAN membranes are promising separator candidate for high-performance Li-ion batteries.

  20. Experimental study of xenon isotopes production by gas centrifuge

    International Nuclear Information System (INIS)

    Zhou Mingsheng; Liang Xiongwen; Zhang Yonggang; Dong Jinping

    2006-01-01

    The gas centrifuge technology is studied for the separation of Xe isotopes. The nature Xe is chosen as processing gas. A four-state cascade is designed to separate 124 Xe to a concentration of being greater than 65% in three separation runs. 124 Xe can be enriched to a concentration 99% in more separation runs using a cascade of more gas centrifuges. (authors)

  1. Separation of gold nanorods by viscosity gradient centrifugation

    International Nuclear Information System (INIS)

    Dong, Suli; Wang, Yawei; Li, Xiaogang; Zhang, Qingquan; Liu, Xiaojun; Tu, Yang; Liang, Aiye

    2016-01-01

    Size-uniform gold nanorods (Au-NRs) are used in biosensing, bioimaging, photothermal therapy, drug and gene delivery, and controlled release. Monodisperse Au-NRs are usually obtained by separation steps following their synthesis, and centrifugation is widely used because of the ease of operation, high recovery, and the good availability of equipment. So far, the effect of viscosity on the separation of Au-NRs has not been investigated. We have developed a method for separation of monodisperse Au-NRs that is based on centrifugation in a viscosity gradient. Monodisperse Au-NRs obtained from gold nanoparticles were obtained by centrifugation in viscosity gradient adjusted with poly(2-ethyl-2-oxazoline). Au-NRs in sizes ranging from 25.6 to 26.1 nm in effective radius can be separated 5500 g within 5 min, which appears to be the fastest method for separation of Au-NRs. (author)

  2. Space Station Centrifuge: A Requirement for Life Science Research

    Science.gov (United States)

    Smith, Arthur H.; Fuller, Charles A.; Johnson, Catherine C.; Winget, Charles M.

    1992-01-01

    A centrifuge with the largest diameter that can be accommodated on Space Station Freedom is required to conduct life science research in the microgravity environment of space. (This was one of the findings of a group of life scientists convened at the University of California, Davis, by Ames Research Center.) The centrifuge will be used as a research tool to understand how gravity affects biological processes; to provide an on-orbit one-g control; and to assess the efficacy of using artificial gravity to counteract the deleterious biological effect of space flight. The rationale for the recommendation and examples of using ground-based centrifugation for animal and plant acceleration studies are presented. Included are four appendixes and an extensive bibliography of hypergravity studies.

  3. Dysrhythmias in Laypersons During Centrifuge-Simulated Suborbital Spaceflight.

    Science.gov (United States)

    Suresh, Rahul; Blue, Rebecca S; Mathers, Charles H; Castleberry, Tarah L; Vanderploeg, James M

    2017-11-01

    There are limited data on cardiac dysrhythmias in laypersons during hypergravity exposure. We report layperson electrocardiograph (ECG) findings and tolerance of dysrhythmias during centrifuge-simulated suborbital spaceflight. Volunteers participated in varied-length centrifuge training programs of 2-7 centrifuge runs over 0.5-2 d, culminating in two simulated suborbital spaceflights of combined +Gz and +Gx (peak +4.0 Gz, +6.0 Gx, duration 5 s). Monitors recorded pre- and post-run mean arterial blood pressure (MAP), 6-s average heart rate (HR) collected at prespecified points during exposures, documented dysrhythmias observed on continuous 3-lead ECG, self-reported symptoms, and objective signs of intolerance on real-time video monitoring. Participating in the study were 148 subjects (43 women). Documented dysrhythmias included sinus pause (N = 5), couplet premature ventricular contractions (N = 4), bigeminy (N = 3), accelerated idioventricular rhythm (N = 1), and relative bradycardia (RB, defined as a transient HR drop of >20 bpm; N = 63). None were associated with subjective symptoms or objective signs of acceleration intolerance. Episodes of RB occurred only during +Gx exposures. Subjects had a higher post-run vs. pre-run MAP after all exposures, but demonstrated no difference in pre- and post-run HR. RB was more common in men, younger individuals, and subjects experiencing more centrifuge runs. Dysrhythmias in laypersons undergoing simulated suborbital spaceflight were well tolerated, though RB was frequently noted during short-duration +Gx exposure. No subjects demonstrated associated symptoms or objective hemodynamic sequelae from these events. Even so, heightened caution remains warranted when monitoring dysrhythmias in laypersons with significant cardiopulmonary disease or taking medications that modulate cardiac conduction.Suresh R, Blue RS, Mathers CH, Castleberry TL, Vanderploeg JM. Dysrhythmias in laypersons during centrifuge-stimulated suborbital

  4. Adiabatic Field-Free Alignment of Asymmetric Top Molecules with an Optical Centrifuge.

    Science.gov (United States)

    Korobenko, A; Milner, V

    2016-05-06

    We use an optical centrifuge to align asymmetric top SO_{2} molecules by adiabatically spinning their most polarizable O-O axis. The effective centrifugal potential in the rotating frame confines the sulfur atoms to the plane of the laser-induced rotation, leading to the planar molecular alignment that persists after the molecules are released from the centrifuge. The periodic appearance of the full three-dimensional alignment, typically observed only with linear and symmetric top molecules, is also detected. Together with strong in-plane centrifugal forces, which bend the molecules by up to 10 deg, permanent field-free alignment offers new ways of controlling molecules with laser light.

  5. Continuous-flow centrifugation to collect suspended sediment for chemical analysis

    Science.gov (United States)

    Conn, Kathleen E.; Dinicola, Richard S.; Black, Robert W.; Cox, Stephen E.; Sheibley, Richard W.; Foreman, James R.; Senter, Craig A.; Peterson, Norman T.

    2016-12-22

    Recent advances in suspended-sediment monitoring tools and surrogate technologies have greatly improved the ability to quantify suspended-sediment concentrations and to estimate daily, seasonal, and annual suspended-sediment fluxes from rivers to coastal waters. However, little is known about the chemical composition of suspended sediment, and how it may vary spatially between water bodies and temporally within a single system owing to climate, seasonality, land use, and other natural and anthropogenic drivers. Many water-quality contaminants, such as organic and inorganic chemicals, nutrients, and pathogens, preferentially partition in sediment rather than water. Suspended sediment-bound chemical concentrations may be undetected during analysis of unfiltered water samples, owing to small water sample volumes and analytical limitations. Quantification of suspended sediment‑bound chemical concentrations is needed to improve estimates of total chemical concentrations, chemical fluxes, and exposure levels of aquatic organisms and humans in receiving environments. Despite these needs, few studies or monitoring programs measure the chemical composition of suspended sediment, largely owing to the difficulty in consistently obtaining samples of sufficient quality and quantity for laboratory analysis.A field protocol is described here utilizing continuous‑flow centrifugation for the collection of suspended sediment for chemical analysis. The centrifuge used for development of this method is small, lightweight, and portable for the field applications described in this protocol. Project scoping considerations, deployment of equipment and system layout options, and results from various field and laboratory quality control experiments are described. The testing confirmed the applicability of the protocol for the determination of many inorganic and organic chemicals sorbed on suspended sediment, including metals, pesticides, polycyclic aromatic hydrocarbons, and

  6. Optimisation of a double-centrifugation method for preparation of canine platelet-rich plasma.

    Science.gov (United States)

    Shin, Hyeok-Soo; Woo, Heung-Myong; Kang, Byung-Jae

    2017-06-26

    Platelet-rich plasma (PRP) has been expected for regenerative medicine because of its growth factors. However, there is considerable variability in the recovery and yield of platelets and the concentration of growth factors in PRP preparations. The aim of this study was to identify optimal relative centrifugal force and spin time for the preparation of PRP from canine blood using a double-centrifugation tube method. Whole blood samples were collected in citrate blood collection tubes from 12 healthy beagles. For the first centrifugation step, 10 different run conditions were compared to determine which condition produced optimal recovery of platelets. Once the optimal condition was identified, platelet-containing plasma prepared using that condition was subjected to a second centrifugation to pellet platelets. For the second centrifugation, 12 different run conditions were compared to identify the centrifugal force and spin time to produce maximal pellet recovery and concentration increase. Growth factor levels were estimated by using ELISA to measure platelet-derived growth factor-BB (PDGF-BB) concentrations in optimised CaCl 2 -activated platelet fractions. The highest platelet recovery rate and yield were obtained by first centrifuging whole blood at 1000 g for 5 min and then centrifuging the recovered platelet-enriched plasma at 1500 g for 15 min. This protocol recovered 80% of platelets from whole blood and increased platelet concentration six-fold and produced the highest concentration of PDGF-BB in activated fractions. We have described an optimised double-centrifugation tube method for the preparation of PRP from canine blood. This optimised method does not require particularly expensive equipment or high technical ability and can readily be carried out in a veterinary clinical setting.

  7. Cavitation simulation and NPSH prediction of a double suction centrifugal pump

    International Nuclear Information System (INIS)

    Li, P; Huang, Y F; Li, J

    2012-01-01

    This paper illustrates the flow field numerical analysis of the double-suction centrifugal pump. For the study of the cavitation flow inside the double-suction centrifugal pump, the professional pump/motor simulation software PumpLinx and its Full Cavitation Model has been employed. According to the PumpLinx calculation result and the Cavitation damage index, the cavitation position, level and the cavitation characteristics of the double-suction centrifugal pump has been predicted. For the further objective, the simulation of the flow field in the double-suction centrifugal pump under different inlet conditions has been carried out. By the result analysis, NPSHr has been predicted; the reliability of the results has been verified by comparing with the experimental data. At the same time, this practice can provide guidance for the optimal design of double-suction pump.

  8. Seismic analysis of plutonium glovebox by MSC/NASTRAN

    International Nuclear Information System (INIS)

    Hirata, Masaru; Ishikawa, Kazuya; Korosawa, Makoto; Fukushima, Susumu; Hoshina, Hirofumi.

    1993-01-01

    Seismic analysis of the structural strength of gloveboxes is important for plutonium confinement evaluation. However, the analytical methods must be developed for evaluating the mutual displacement between the window frame and acrylic resin window panel with regard to plutonium confinement during an earthquake. Therefore, seismic analysis for a standard glovebox in Plutonium Fuel Research Facility at Oarai Research Establishment of JAERI has been conducted by FEM (Finite Element Method) computer code MSC/NASTRAN (MacNeal-Schwendler Corporation NASA Structural Analysis). Modelling of glovebox window frame has been investigated from the results of natural frequency analysis and static analysis. After the acquisition of a suitable model, displacement around the window frame and glovebox structural strength have been evaluated in detail by use of floor response spectrum analysis and time-history (transient response) analysis. (author)

  9. Changing strategy and implementation of a new treatment protocol for cleft palate surgery in "Maria Sklodowska Curie" (MSC) Children's Hospital, Bucharest, Romania.

    Science.gov (United States)

    Spataru, Radu; Mark, Hans

    2014-12-01

    In "Maria Sklodowska Curie" (MSC) Children's Hospital, Bucharest, Romania, cleft palate repair has been performed according to von Langenbeck since 1984. The speech was good in most patients but wide clefts had a high percentage of fistulas, abnormal speech due to short length and limited mobility of the soft palate. In 2009, the protocol was changed to Gothenburg Delayed Hard Palate Closure, (DHPC) technique. The present evaluation was performed to study the implementation of this technique. One hundred and sixty-eight patients with cleft palate were admitted, 89 isolated cleft palate (ICP), 53 unilateral (UCLP) and 26 bilateral (BCLP). In these, 228 surgical interventions were performed. Soft Palate Repair (SPR) and Hard Palate Repair (HPR) were performed with the DHPC procedure. The transfer to this technique was successfully performed in three steps: one team visit to Gothenburg by a surgeon from MSC and two visits by surgeons from Gothenburg to the MSC. Patients with SPR and HPR were operated on without major complications and there were no differences in results between Gothenburg surgeons and MSC surgeons. The interventions with SPR and HPR technique were proven to be easy to teach and learn and successfully performed without major complications. For cleft patients at MSC hospital it has meant earlier surgery, less re-operations and complications. This report shows a successful change of strategy for palatal repair with improved outcome regarding surgery. In future, speech and growth will be followed on a regular basis and will be compared with results from the Gothenburg Cleft Team.

  10. Seismic soil-structure interaction: Analysis and centrifuge model studies

    International Nuclear Information System (INIS)

    Finn, W.D.L.; Ledbetter, R.H.; Beratan, L.L.

    1986-01-01

    A method for nonlinear dynamic effective stress analysis applicable to soil-structure interaction problems is introduced. Full interaction including slip between structure and foundation is taken into account and the major factors that must be considered when computing dynamic soil response are included. An experimental investigation using simulated earthquake tests on centrifuged geotechnical models was conducted to obtain prototype response data of foundation soils carrying both surface and embedded structures and to validate the dynamic effective stress analysis. The centrifuge tests were conducted in the Geotechnical Centrifuge at Cambridge University, England. Horizontal and vertical accelerations were measured at various points on structures and in the sand foundation. Seismically induced pore water pressure changes were also measured at various locations in the foundation. Computer plots of the data were obtained while the centrifuge was in flight and representative samples are presented. The results clearly show the pronounced effect of increasing pore water pressures on dynamic response. It is demonstrated that a coherent picture of dynamic response of soil-structure systems is provided by dynamic effective stress nonlinear analysis. On the basis of preliminary results, it appears that the effects of pore water pressure can be predicted. (orig.)

  11. The Optimal Hydraulic Design of Centrifugal Impeller Using Genetic Algorithm with BVF

    Directory of Open Access Journals (Sweden)

    Xin Zhou

    2014-01-01

    Full Text Available Derived from idea of combining the advantages of two-dimensional hydraulic design theory, genetic algorithm, and boundary vorticity flux diagnosis, an optimal hydraulic design method of centrifugal pump impeller was developed. Given design parameters, the desired optimal centrifugal impeller can be obtained after several iterations by this method. Another 5 impellers with the same parameters were also designed by using single arc, double arcs, triple arcs, logarithmic spiral, and linear-variable angle spiral as blade profiles to make comparisons. Using Reynolds averaged N-S equations with a RNG k-ε two-equation turbulence model and log-law wall function to solve 3D turbulent flow field in the flow channel between blades of 6 designed impellers by CFD code FLUENT, the investigation on velocity distributions, pressure distributions, boundary vorticity flux distributions on blade surfaces, and hydraulic performance of impellers was presented and the comparisons of impellers by different design methods were demonstrated. The results showed that the hydraulic performance of impeller designed by this method is much better than the other 5 impellers under design operation condition with almost the same head, higher efficiency, and lower rotating torque, which implied less hydraulic loss and energy consumption.

  12. Proliferative and phenotypical characteristics of human adipose tissue-derived stem cells: comparison of Ficoll gradient centrifugation and red blood cell lysis buffer treatment purification methods.

    Science.gov (United States)

    Najar, Mehdi; Rodrigues, Robim M; Buyl, Karolien; Branson, Steven; Vanhaecke, Tamara; Lagneaux, Laurence; Rogiers, Vera; De Kock, Joery

    2014-09-01

    Adult human subcutaneous adipose tissue harbors a multipotent stem cell population, the so-called human adipose tissue-derived mesenchymal stromal cells (AT-MSCs). These cells are able to differentiate in vitro into various cell types and possess immunomodulatory features. Yet procedures to obtain AT-MSCs can vary significantly. The two most extensively used AT-MSC purification techniques are (i) density gradient centrifugation using Ficoll and (ii) red blood cell (RBC) lysis buffer treatment of the stromal vascular fraction. In the context of potential clinical cell therapy, the stem cell yield after purification and upon consecutive passages, as well as the purity of the obtained cell population, are of utmost importance. We investigated the expansion capacity and purity of AT-MSCs purified by both procedures immediately after isolation and upon consecutive passages. We also investigated possible purification-dependent differences in their expression of immune-inhibitory factors and cell adhesion molecules. We found that RBC lysis buffer treatment is a more robust and easier method to purify AT-MSCs than density gradient fractionation. However, the resulting AT-MSC-RBC population contains a significantly higher number of CD34(+) cells, particularly during the first passages after plating. From passage 4 onward, no significant differences could be observed between both populations with respect to the immunophenotype, expansion capacity and expression of immune inhibitory factors and cell adhesion molecules. Our data show that RBC lysis buffer treatment may be a good alternative to density fractionation, providing a faster, more robust and easier method to purify AT-MSCs with biologically preserved characteristics. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  13. System Trade-Off Study and Opto-Thermo Analysis of a Sunshield on the MSC of the KOMPSAT-2

    Directory of Open Access Journals (Sweden)

    Young-Soo Kim

    2003-12-01

    Full Text Available The Multi-Spectral Camera (MSC is the payload of KOMPSAT-2 which is designed for earth imaging in optical and near-infrared region on a sun-synchronous orbit. The telescope in the MSC is a Ritchey-Chretien type with large aperture. The telescope structure should be well stabilized and the optical alignment should be kept steady so that best images can be achieved. However, the MSC is exposed to adverse thermal environment on the orbit which can give impacts on optical performance. Solar incidence can bring non-uniform temperature rise on the telescope tube which entails unfavorable thermal distortion. Three ways of preventing the solar radiation were proposed, which were installing external mechanical shield, internal shield, and maneuvering the spacecraft. After trade-off study, internal sun shield was selected as a practical and optimal solution to minimize the effect of the solar radiation. In addition, detailed designs of the structure and sunshield were produced and analyses have been performed. The results were assessed to verify their impacts to the image quality. It was confirmed that the internal sunshield complies with the requirements and would improve image quality.

  14. Subject anxiety and psychological considerations for centrifuge-simulated suborbital spaceflight.

    Science.gov (United States)

    Mulcahy, Robert A; Blue, Rebecca S; Vardiman, Johnené L; Mathers, Charles H; Castleberry, Tarah L; Vanderploeg, James M

    2014-08-01

    Anxiety and psychological concerns may pose a challenge to future commercial spaceflight. To help identify potential measures of anxiousness and indicators of flight-related stress, the psychiatric histories and anxiousness responses of volunteers exposed to G forces in centrifuge-simulated spaceflight acceleration profiles were examined. Over 2 d, 86 individuals (63 men, 23 women), 20-78 yr old, underwent up to 7 centrifuge runs. Day 1 consisted of two +G(z) runs (peak = +3.5 G(z)) and two +Gx runs (peak = +6.0 G(x)). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +G(x) and +G(z)). Hemodynamic data were collected during the profiles. Subjects completed a retrospective self-report anxiety questionnaire. Medical monitors identified individuals exhibiting varying degrees of anxiousness during centrifuge exposure, medical histories of psychiatric disease, and other potential indicators of psychological intolerance of spaceflight. The retrospective survey identified 18 individuals self-reporting anxiousness, commonly related to unfamiliarity with centrifuge acceleration and concerns regarding medical history. There were 12 individuals (5 men, 7 women, average age 46.2 yr) who were observed to have anxiety that interfered with their ability to complete training; of these, 4 reported anxiousness on their questionnaire and 9 ultimately completed the centrifuge profiles. Psychiatric history was not significantly associated with anxious symptoms. Anxiety is likely to be a relevant and potentially disabling problem for commercial spaceflight participants; however, positive psychiatric history and self-reported symptoms did not predict anxiety during centrifuge performance. Symptoms of anxiousness can often be ameliorated through training and coaching. Even highly anxious individuals are likely capable of tolerating commercial spaceflight.

  15. Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

    Energy Technology Data Exchange (ETDEWEB)

    Mahl, Dirk; Diendorf, Joerg; Ristig, Simon [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Greulich, Christina [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Li Zian; Farle, Michael [University of Duisburg-Essen, Faculty of Physics, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Koeller, Manfred [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Epple, Matthias, E-mail: matthias.epple@uni-due.de [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)

    2012-10-15

    Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly(N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 {mu}g mL{sup -1} induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  16. Silver, gold, and alloyed silver–gold nanoparticles: characterization and comparative cell-biologic action

    International Nuclear Information System (INIS)

    Mahl, Dirk; Diendorf, Jörg; Ristig, Simon; Greulich, Christina; Li Zian; Farle, Michael; Köller, Manfred; Epple, Matthias

    2012-01-01

    Silver, gold, and silver–gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly(N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15–25 nm), gold (5–6 nm), and silver–gold (50:50; 10–12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver–gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver–gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver–gold nanoparticles in the concentration range of 5–20 μg mL −1 induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  17. Multi-objective optimization design and experimental investigation of centrifugal fan performance

    Science.gov (United States)

    Zhang, Lei; Wang, Songling; Hu, Chenxing; Zhang, Qian

    2013-11-01

    Current studies of fan performance optimization mainly focus on two aspects: one is to improve the blade profile, and another is only to consider the influence of single impeller structural parameter on fan performance. However, there are few studies on the comprehensive effect of the key parameters such as blade number, exit stagger angle of blade and the impeller outlet width on the fan performance. The G4-73 backward centrifugal fan widely used in power plants is selected as the research object. Based on orthogonal design and BP neural network, a model for predicting the centrifugal fan performance parameters is established, and the maximum relative errors of the total pressure and efficiency are 0.974% and 0.333%, respectively. Multi-objective optimization of total pressure and efficiency of the fan is conducted with genetic algorithm, and the optimum combination of impeller structural parameters is proposed. The optimized parameters of blade number, exit stagger angle of blade and the impeller outlet width are seperately 14, 43.9°, and 21 cm. The experiments on centrifugal fan performance and noise are conducted before and after the installation of the new impeller. The experimental results show that with the new impeller, the total pressure of fan increases significantly in total range of the flow rate, and the fan efficiency is improved when the relative flow is above 75%, also the high efficiency area is broadened. Additionally, in 65% -100% relative flow, the fan noise is reduced. Under the design operating condition, total pressure and efficiency of the fan are improved by 6.91% and 0.5%, respectively. This research sheds light on the considering of comprehensive effect of impeller structrual parameters on fan performance, and a new impeller can be designed to satisfy the engineering demand such as energy-saving, noise reduction or solving air pressure insufficiency for power plants.

  18. Centrifugation: an important pre-analytic procedure that influences plasma microRNA quantification during blood processing.

    Science.gov (United States)

    Zheng, Xiao-Hui; Cui, Cui; Zhou, Xin-Xi; Zeng, Yi-Xin; Jia, Wei-Hua

    2013-12-01

    Circulating microRNAs are robustly present in plasma or serum and have become a research focus as biomarkers for tumor diagnosis and prognosis. Centrifugation is a necessary procedure for obtaining high-quality blood supernatant. Herein, we investigated one-step and two-step centrifugations, two centrifugal methods routinely used in microRNA study, to explore their effects on plasma microRNA quantification. The microRNAs obtained from one-step and two-step centrifugations were quantified by microarray and TaqMan-based real-time quantitative polymerase chain reaction (Q-PCR). Dynamic light scattering was performed to explore the difference underlying the two centrifugal methods. The results from the microarray containing 1,347 microRNAs showed that the signal detection rate was greatly decreased in the plasma sample prepared by two-step centrifugation. More importantly, the microRNAs missing in this plasma sample could be recovered and detected in the precipitate generated from the second centrifugation. Consistent with the results from microarray, a marked decrease of three representative microRNAs in two-step centrifugal plasma was validated by Q-PCR. According to the size distribution of all nanoparticles in plasma, there were fewer nanoparticles with size >1,000 nm in two-step centrifugal plasma. Our experiments directly demonstrated that different centrifugation methods produced distinct quantities of plasma microRNAs. Thus, exosomes or protein complexes containing microRNAs may be involved in large nanoparticle formation and may be precipitated after two-step centrifugation. Our results remind us that sample processing methods should be first considered in conducting research.

  19. Comparing estimates of EMEP MSC-Wand UFORE models in air pollutant reduction by urban trees

    Czech Academy of Sciences Publication Activity Database

    Guidolotti, G.; Salvatio, M.; Calfapietra, Carlo

    2016-01-01

    Roč. 23, č. 19 (2016), s. 19541-19550 ISSN 0944-1344 Institutional support: RVO:67179843 Keywords : i-Tree * UFORE, EMEP/MSC-Wmodel * urban forest * atmospheric pollutants * O3 * NO2 * PM10 Subject RIV: EF - Botanics Impact factor: 2.741, year: 2016

  20. Continuous centrifuge decelerator for polar molecules.

    Science.gov (United States)

    Chervenkov, S; Wu, X; Bayerl, J; Rohlfes, A; Gantner, T; Zeppenfeld, M; Rempe, G

    2014-01-10

    Producing large samples of slow molecules from thermal-velocity ensembles is a formidable challenge. Here we employ a centrifugal force to produce a continuous molecular beam with a high flux at near-zero velocities. We demonstrate deceleration of three electrically guided molecular species, CH3F, CF3H, and CF3CCH, with input velocities of up to 200  m s(-1) to obtain beams with velocities below 15  m s(-1) and intensities of several 10(9)  mm(-2) s(-1). The centrifuge decelerator is easy to operate and can, in principle, slow down any guidable particle. It has the potential to become a standard technique for continuous deceleration of molecules.

  1. A vibration model for centrifugal contactors

    International Nuclear Information System (INIS)

    Leonard, R.A.; Wasserman, M.O.; Wygmans, D.G.

    1992-11-01

    Using the transfer matrix method, we created the Excel worksheet ''Beam'' for analyzing vibrations in centrifugal contactors. With this worksheet, a user can calculate the first natural frequency of the motor/rotor system for a centrifugal contactor. We determined a typical value for the bearing stiffness (k B ) of a motor after measuring the k B value for three different motors. The k B value is an important parameter in this model, but it is not normally available for motors. The assumptions that we made in creating the Beam worksheet were verified by comparing the calculated results with those from a VAX computer program, BEAM IV. The Beam worksheet was applied to several contactor designs for which we have experimental data and found to work well

  2. Design of ideal cascades of gas centrifuges with variable separation factors

    International Nuclear Information System (INIS)

    Olander, D.R.

    1976-01-01

    A method of designing ideal cascades in which the separation factor varies with stage number is presented and applied to centrifuges as separating units. The centrifuge is characterized by a performance function, which gives the separative power, optimized with respect to all internal variables, as a function of cut and throughput. For centrifuges with certain types of performance functions, variable-α ideal cascades can provide a product at a lower cost than the conventional ideal cascade in which the separation factor is independent of stage number

  3. Sand characterization by combined centrifuge and laboratory tests

    OpenAIRE

    GAUDIN, C; SCHNAID, F; GARNIER, J

    2005-01-01

    The purpose of this paper is to evaluate new methods of interpretation of in situ tests in sand from correlations established from centrifuge and laboratory data. Emphasis is given to methods that are based on the combination of measurements from independent tests, such as the ratio of the elastic stiffness to ultimate strenght and the ratio of cone resistance and limit pressure. For that purpose, a series of centrifuge tests using a cone penetrometer and a cone pressuremeter was carried out ...

  4. Study on flow fields in high specific speed centrifugal compressor with unpinched vaneless diffuser

    International Nuclear Information System (INIS)

    Tamaki, Hideaki

    2013-01-01

    Performance of centrifugal compressors strongly depends on their internal flow fields. CFD has become indispensable tool for getting the information about flow fields in centrifugal compressors. CFD codes are usually validated by some representative data or compared with calculated results by other CFD codes, in order to ensure their accuracies. However, learning their accuracies for all types of centrifugal compressor's specifications requires continuous works that compare experimental data obtained in developmental processes of various types of centrifugal compressors with CFD results. A prediction of a performance and a flow field of a centrifugal compressor by CFD is relatively accurate when the impact of separation and secondary flow on that flow field is weak, i.e. near design condition. Centrifugal compressors are deemed to have a wide operating range alongside high efficiencies at design points. Hence the prediction accuracy of CFD at off design conditions, where the impacts of separation and secondary flow on the flow field are strong, is critical for the design of the centrifugal compressors. This study therefore investigated the prediction accuracy of CFD using a centrifugal compressor whose geometry was intentionally changed to have a distorted flow field over a whole operating range, i.e. from choke to surge.

  5. Study on flow fields in high specific speed centrifugal compressor with unpinched vaneless diffuser

    Energy Technology Data Exchange (ETDEWEB)

    Tamaki, Hideaki [IHI Corporation, Yokoham (Japan)

    2013-06-15

    Performance of centrifugal compressors strongly depends on their internal flow fields. CFD has become indispensable tool for getting the information about flow fields in centrifugal compressors. CFD codes are usually validated by some representative data or compared with calculated results by other CFD codes, in order to ensure their accuracies. However, learning their accuracies for all types of centrifugal compressor's specifications requires continuous works that compare experimental data obtained in developmental processes of various types of centrifugal compressors with CFD results. A prediction of a performance and a flow field of a centrifugal compressor by CFD is relatively accurate when the impact of separation and secondary flow on that flow field is weak, i.e. near design condition. Centrifugal compressors are deemed to have a wide operating range alongside high efficiencies at design points. Hence the prediction accuracy of CFD at off design conditions, where the impacts of separation and secondary flow on the flow field are strong, is critical for the design of the centrifugal compressors. This study therefore investigated the prediction accuracy of CFD using a centrifugal compressor whose geometry was intentionally changed to have a distorted flow field over a whole operating range, i.e. from choke to surge.

  6. [Effect of Parasep® feces centrifuge tube method on detecting schistosome eggs].

    Science.gov (United States)

    Ma, Nian; Zhang, Hua-ming; Liu, Xiong; Xiao, Chuan-yun; Wen, Xiao-hong; Li, Xia; Dong, Li-chun; Cui, Cai-xia; Tu, Zu-wu

    2014-08-01

    To evaluate the effect of the Parasep® feces centrifuge tube method on detecting schistosome eggs. A total of 803 residents aged from 6-65 years were selected in 2 schistosomiasis endemic villages, Jiangling County, Hubei Province, and their stool samples were collected and detected parallelly by the Kato-Katz technique, nylon silk egg hatching method, and Parasep® feces centrifuge tube method at the same time. Among the 803 people, 15 cases were found of schistosome egg positive, and the positive rate was 1.87%. The positive rates of the Kato-Katz technique, nylon silk egg hatching method, and Parasep® feces centrifuge tube method were 0.75%, 1.49% and 1.12%, respectively. The schistosome eggs got with the Parasep® feces centrifuge tube method were clear and easy to identify. In low endemic areas of schistosomiasis, the Parasep® feces centrifuge tube method can be used as schistosomiasis japonica etiology diagnosis method.

  7. The impact of the centrifuge characteristics and centrifugation protocols on the cells, growth factors, and fibrin architecture of a leukocyte- and platelet-rich fibrin (L-PRF) clot and membrane.

    Science.gov (United States)

    Dohan Ehrenfest, David M; Pinto, Nelson R; Pereda, Andrea; Jiménez, Paula; Corso, Marco Del; Kang, Byung-Soo; Nally, Mauricio; Lanata, Nicole; Wang, Hom-Lay; Quirynen, Marc

    2018-03-01

    L-PRF (leukocyte- and platelet-rich fibrin) is one of the four families of platelet concentrates for surgical use and is widely used in oral and maxillofacial regenerative therapies. The first objective of this article was to evaluate the mechanical vibrations appearing during centrifugation in four models of commercially available table-top centrifuges used to produce L-PRF and the impact of the centrifuge characteristics on the cell and fibrin architecture of a L-PRF clot and membrane. The second objective of this article was to evaluate how changing some parameters of the L-PRF protocol may influence its biological signature, independently from the characteristics of the centrifuge. In the first part, four different commercially available centrifuges were used to produce L-PRF, following the original L-PRF production method (glass-coated plastic tubes, 400 g force, 12 minutes). The tested systems were the original L-PRF centrifuge (Intra-Spin, Intra-Lock, the only CE and FDA cleared system for the preparation of L-PRF) and three other laboratory centrifuges (not CE/FDA cleared for L-PRF): A-PRF 12 (Advanced PRF, Process), LW-UPD8 (LW Scientific) and Salvin 1310 (Salvin Dental). Each centrifuge was opened for inspection, two accelerometers were installed (one radial, one vertical), and data were collected with a spectrum analyzer in two configurations (full-load or half load). All clots and membranes were collected into a sterile surgical box (Xpression kit, Intra-Lock). The exact macroscopic (weights, sizes) and microscopic (photonic and scanning electron microscopy SEM) characteristics of the L-PRF produced with these four different machines were evaluated. In the second part, venous blood was taken in two groups, respectively, Intra-Spin 9 ml glass-coated plastic tubes (Intra-Lock) and A-PRF 10 ml glass tubes (Process). Tubes were immediately centrifuged at 2700 rpm (around 400 g) during 12 minutes to produce L-PRF or at 1500 rpm during 14 minutes to produce A

  8. Study on the performance of the hydraulic and mass-transfer with miniature centrifugal contactor

    International Nuclear Information System (INIS)

    Wang Jianchen; Tang Wencheng; Fan Shilei; Lian Jun

    1997-01-01

    The hydraulic performance and the mass-transfer properties of HNO 3 , Fe 3+ , Nd 3+ are studied in H 2 O-30% TRPO-kerosene system at different conditions with single-stage φ = 10 mm miniature centrifugal contactor. The rotor's speed varies from 4000 r/min to 4500 r/min. The total throughput is less than 600 mL/h. the phase ratio(o/a) changes from 1/10 to 10/1. Under the above experimental conditions, the single contactor operates very well and gives good performance. The stage efficiencies of HNO 3 and Nd 3+ are about 90%. The Fe 3+ extraction is very slow kinetically and the stage efficiency of Fe 3+ is low

  9. Runtime and Inversion Impacts on Estimation of Moisture Retention Relations by Centrifuge

    Science.gov (United States)

    Sigda, J. M.; Wilson, J. L.

    2003-12-01

    Standard laboratory methods in soil physics for measuring the moisture retention relation (drainage matric potential-volumetric moisture content relation) are each limited to only part of the moisture content range. Centrifuge systems allow intensive accurate measurements across much of the saturation range, and typically require much less time than traditional laboratory methods. An initially liquid-saturated sample is subjected to a stepwise-increasing series of angular velocities while carefully monitoring changes in liquid content. Angular velocity is held constant until the capillary and centrifugal forces equilibrate, forcing liquid flux to zero, and then a final average liquid content is noted. The procedure is repeated after increasing the angular velocity. Centrifuge measurement time is greatly reduced because the centrifugal body force gradient can far exceed the driving forces utilized in standard lab methods. Widely-used in the petroleum industry for decades, centrifuge measurement of moisture retention relations is seldom encountered in the soil physics or vadose hydrology literatures. Yet there is a need to better understand and improve the experimental methodology given the increasing number of centrifuges employed in these fields. Errors in centrifuge measurement of moisture retention relations originate from both experimental protocol and from data inversion. Like standard methods, centrifuge methods assume equilibrium conditions, and so are sensitive to errors introduced by insufficient runtimes. Unlike standard methods, centrifuge experiments require inversion of the angular velocity and average sample moisture content data to a location-specific pair of matric potential and moisture content values, The force balance causes matric potential and moisture content to vary with sample length while the sample is spinning. Numerous data inversion techniques exist, each yielding different moisture retention relations. We present analyses demonstrating

  10. A small population of resident limb bud mesenchymal cells express few MSC-associated markers, but the expression of these markers is increased immediately after cell culture.

    Science.gov (United States)

    Marín-Llera, Jessica Cristina; Chimal-Monroy, Jesús

    2018-05-01

    Skeletal progenitors are derived from resident limb bud mesenchymal cells of the vertebrate embryos. However, it remains poorly understood if they represent stem cells, progenitors, or multipotent mesenchymal stromal cells (MSC). Derived-MSC of different adult tissues under in vitro experimental conditions can differentiate into the same cellular lineages that are present in the limb. Here, comparing non-cultured versus cultured mesenchymal limb bud cells, we determined the expression of MSC-associated markers, the in vitro differentiation capacity and their gene expression profile. Results showed that in freshly isolated limb bud mesenchymal cells, the proportion of cells expressing Sca1, CD44, CD105, CD90, and CD73 is very low and a low expression of lineage-specific genes was observed. However, recently seeded limb bud mesenchymal cells acquired Sca1 and CD44 markers and the expression of the key differentiation genes Runx2 and Sox9, while Scx and Pparg genes decreased. Also, their chondrogenic differentiation capacity decreased through cellular passages while the osteogenic increased. Our findings suggest that the modification of the cell adhesion process through the in vitro method changed the limb mesenchymal cell immunophenotype leading to the expression and maintenance of common MSC-associated markers. These findings could have a significant impact on MSC study and isolation strategy because they could explain common variations observed in the MSC immunophenotype in different tissues. © 2018 International Federation for Cell Biology.

  11. The influence of aerosol density upon the performance of centrifugal spectrometers

    International Nuclear Information System (INIS)

    Martonen, T.B.

    1978-01-01

    Centrifugal instruments are valuable components for studying airborne particulate matter of health physics interest because a continuously graded aerodynamic diameter, Dae, spectrum is produced. Applications include the characterization of inhalation exposure aerosols, serving as particle monitors to measure respirable dose, and being the integral unit in a system to generate monodisperse aerosols. Some aerosols of health physics concern differ from the PSL aerosol used to calibrate centrifuges in two main respects: the particulate mass concentration, Cm, is large, and the aerosol gas is not air. The marked influence of these factors upon centrifuge performance is documented (T. B. Martonen, Ph.D. Thesis, University of Rochester, Rochester, NY, 1976). The phenomenon of cloud settling occurs when Cm is of sufficient magnitude. Aerosol gas effects can be defined in terms of the parameter K, the ratio of the aerosol gas to winnowing medium densities. Size classification is modified by diffusiophoretic forces when K 1. In all cases, erroneous size distribution data results. Laboratory procedures are presented which permit accurate particle size assessment when aerosols of large Cm and/or K≠1 are sampled. An engineering analysis of centrifuge physics has been completed which allows optimum operating conditions, which may be quite different for different aerosols, to be computed. Cigarette smoke was used as a test aerosol to check the experimental and theoretical findings. Although it is shown to be subject to both cloud settling and dense gas subsidence, accurate size classification was obtained. The differential equation describing particle motion in centrifuges has been formulated and solved. Further, techniques of dimensional analysis were applied to the equations modelling flow in centrifuges; results indicate how operating conditions and instrument geometry influence particle size classification. These theoretical studies will lead to the development of improved

  12. Centrifugation after irradiation of red blood cells does not accelerate haemolysis.

    Science.gov (United States)

    Weiss, Dominik R; Goehring, Jasmin; Weisbach, Volker; Strasser, Erwin F; Ringwald, Juergen; Zimmermann, Robert; Eckstein, Reinhold

    2011-01-01

    For intrauterine transfusion and some other rare indications, irradiation and washing or adjustment to an elevated haematocrit is necessary. No data are currently available indicating whether irradiation of red blood cell concentrates (RBCs) might impair the mechanical stability of erythrocytes during centrifugation leading to elevated haemolysis. Consequently, if irradiation and centrifugation of RBCs is necessary, there is no definitive recommendation about the preferred sequence of steps. We divided 20 RBC units that were not older than 9 days into two subunits. These subunits were prepared to yield irradiated RBCs with an elevated haematocrit, as they are used for intrauterine transfusion. One subunit was centrifuged and then irradiated, the other subunit was irradiated and then centrifuged. The units were evaluated in vitro before preparation and on days 1 and 7. We could not find any difference in the haemolysis rate, extracellular LDH or alpha-HBDH between the two groups of RBCs. This observation indicates that centrifugation after irradiation of RBCs does not accelerate haemolysis. A similar ATP content in the two subunits demonstrated no difference in energy metabolism. The extracellular potassium concentration was significantly lower in the subunits washed after irradiation. There is no difference in the haemolysis caused by centrifugation between irradiated and non-irradiated RBCs. However, it is well known that washing RBCs after irradiation significantly lowers the potassium content. Summarising these two findings leads to the conclusion that it is optimal first to irradiate and then to wash RBCs.

  13. Use of short-radius centrifugation to augment ankle-brachial indices.

    Science.gov (United States)

    Grenon, S Marlene; Mateus, Jaime; Hsiang, York; Sidhu, Ravi; Young, Laurence; Gagnon, Joel

    2009-06-01

    Peripheral arterial disease is mainly caused by atherosclerosis and is characterized by decreased circulation, lower blood pressure, and insufficient tissue perfusion in the lower extremities. The hemodynamics of standing and altered gravity environments have been well studied relative to arm blood pressures but are less well understood for ankle pressures. Because regional blood pressure depends, in part, on the gravitational pressure gradient, we hypothesized that artificial gravity exposure on a short-arm centrifuge with the center of rotation above the head would increase blood pressure in the lower extremities. Cardiovascular parameters for 12 healthy subjects were measured during exposure to supine short-arm centrifugation at 20, 25, and 30 revolutions per minute (rpm), corresponding to centripetal accelerations of 0.94, 1.47, and 2.11 Gz at the foot level, respectively. Systolic ankle blood pressure significantly increased at all levels of centrifugation. Ankle-brachial indices (the ratio of systolic ankle to arm blood pressures) increased significantly from 1.17 +/- 0.03 to 1.58 +/- 0.03 at 0.94 Gz (P blood pressure significantly increased at 2.11 Gz, but heart rate did not change significantly. All parameters returned to normal after cessation of centrifugation. We demonstrated that short-radius centrifugation leads to an increase in ankle-brachial indices. This could have potential implications for the treatment of peripheral arterial disease.

  14. Prediction and Reduction of Aerodynamic Noise of the Multiblade Centrifugal Fan

    Directory of Open Access Journals (Sweden)

    Shuiqing Zhou

    2014-08-01

    Full Text Available An aerodynamic and aeroacoustic investigation of the multiblade centrifugal fan is proposed in this paper, and a hybrid technique of combining flow field calculation and acoustic analysis is applied to solve the aeroacoustic problem of multiblade centrifugal fan. The unsteady flow field of the multiblade centrifugal fan is predicted by solving the incompressible Reynolds-averaged Navier-Stokes (RANS equations with conventional computing techniques for fluid dynamics. The principal noise source induced is extracted from the calculation of the flow field by using acoustic principles, and the modeled sources on inner and outer surfaces of the volute are calculated with multiregional boundary element method (BEM. Through qualitative analysis, the sound pressure amplitude distribution of the multiblade centrifugal fan in near field is given and the sound pressure level (SPL spectrum diagram of monitoring points in far field is obtained. Based on the analysis results, the volute tongue structure is adjusted and then a low-noise design for the centrifugal fan is proposed. The comparison of noise tests shows the noise reduction of improved fan model is more obvious, which is in good agreement with the prediction using the hybrid techniques.

  15. A novel centrifugal separator: conceptual design and analysis of system dynamics

    International Nuclear Information System (INIS)

    Bhardwaj, Utsav

    2016-01-01

    In the processes related to nuclear fuel cycle, we encounter some sort of slurries, like nuclear waste slurries, which need treatment for separation of suspended solids. There are several techniques to accomplish this purpose, like using some chemical action (like that for separation of nuclear fuel ore or for separation of some specific nuclear waste), sedimentation, enhanced sedimentation or forced precipitation using some sort of additives, passage through a specifically designed constricted flow way, centrifugal separation, etc. Centrifugal separation being one of the important techniques used for separation, several centrifugal separators have been designed, developed and being used successfully for a continuously flowing slurry or mixture. The presently designed separator does the process of separation and tries to keep the species once separated isolated uniformly throughout the axial length of the separation region. Some conventional centrifugal separators are non-hermetic too. Here in this paper, a different kind of centrifugal separator has been proposed, which separates the heavier suspended matter as well as the lighter suspended matter from some liquid, that too in bulk in one go. It is very suitable for coarse separation of nuclear ore

  16. Centrifugally cast Zn-27Al-xMg-ySi alloys and their in situ (Mg2Si + Si)/ZA27 composites

    International Nuclear Information System (INIS)

    Wang Qudong; Chen Yongjun; Chen Wenzhou; Wei Yinhong; Zhai Chunquan; Ding Wenjiang

    2005-01-01

    Effects of composition, mold temperature, rotating rate and modification on microstructure of centrifugally cast Zn-27Al-xMg-ySi alloys have been investigated. In situ composites of Zn-27Al-6.3Mg-3.7Si and Zn-27Al-9.8Mg-5.2Si alloys were fabricated by centrifugal casting using heated permanent mold. These composites consist of three layers: inner layer segregates lots of blocky primary Mg 2 Si and a litter blocky primary Si, middle layer contains without primary Mg 2 Si and primary Si, outer layer contains primary Mg 2 Si and primary Si. The position, quantity and distribution of primary Mg 2 Si and primary Si in the composites are determined jointly by alloy composition, solidification velocity under the effect of centrifugal force and their floating velocity inward. Na salt modifier can refine grain and primary Mg 2 Si and make primary Mg 2 Si distribute more evenly and make primary Si nodular. For centrifugally cast Zn-27Al-3.2Mg-1.8Si alloy, the microstructures of inner layer, middle layer and outer layer are almost similar, single layer materials without primary Mg 2 Si and primary Si are obtained, and their grain sizes increased with the mold temperature increasing

  17. Uranium enrichment in Europe by the gas centrifuge process

    International Nuclear Information System (INIS)

    Severin, D.J.E.

    1975-01-01

    To begin with, this lesson gives an outline of the expected energy demand of the Western World and the concentration of the European companies participating in uranium enrichment by the gas centrifuge method. Next, a) the principles of the gas centrifuge method are outlined, b) its advantages over other industrial processes are stressed, and c) the characteristic data of complete plants are given. The existing German, Dutch, and British pilot plants are mentioned as examples for the perfected state of the process. The Capenhurst (UK) and Almedo (NL) demonstration plants, each with a capacity of 200 t SW/a, will have been extended to 2 x 1.000 t SW/a by 1982. Finally, economic data of the gas centrifuge process are given. The term 'separative work' is explained in an annex. (GG) [de

  18. Advances in post-fermented wine clarification by centrifugal technology

    Directory of Open Access Journals (Sweden)

    Giacomo Costagli

    2016-11-01

    Full Text Available Wine clarification processes are deeply determined by complex interaction of wine constituents and application of available technologies as well as use of fining agents. Among others, centrifuge is a consolidated technique applied for many separation duties in the winery. Important advances on improvement of the performance of centrifugal technology have beeen focused on gentle wine treatment, minimal dissolved oxygen and significant reduction of energy consumption helping to dispel old beliefs on a technique considered to be traditional. This paper reviews the development of technology and recent advances on centrifuge improvement and aims to show, through field experimental observation, the importance of removing a portion of particles responsible of haze in the light of very low level of dissolved oxygen and complementarity of alternative recent techniques of wine filtration like cross-flow microfiltration.

  19. Design Optimization of a Centrifugal Fan with Splitter Blades

    Science.gov (United States)

    Heo, Man-Woong; Kim, Jin-Hyuk; Kim, Kwang-Yong

    2015-05-01

    Multi-objective optimization of a centrifugal fan with additionally installed splitter blades was performed to simultaneously maximize the efficiency and pressure rise using three-dimensional Reynolds-averaged Navier-Stokes equations and hybrid multi-objective evolutionary algorithm. Two design variables defining the location of splitter, and the height ratio between inlet and outlet of impeller were selected for the optimization. In addition, the aerodynamic characteristics of the centrifugal fan were investigated with the variation of design variables in the design space. Latin hypercube sampling was used to select the training points, and response surface approximation models were constructed as surrogate models of the objective functions. With the optimization, both the efficiency and pressure rise of the centrifugal fan with splitter blades were improved considerably compared to the reference model.

  20. Spectroscopy of Molecules in Extreme Rotational States Using AN Optical Centrifuge

    Science.gov (United States)

    Mullin, Amy S.; Toro, Carlos; Echibiri, Geraldine; Liu, Qingnan

    2012-06-01

    Our lab has developed a high-power optical centrifuge that is capable of trapping and spinning large number densities of molecules into extreme rotational states. By coupling this device with high resolution transient IR absorption spectroscopy, we measure the time-resolved behavior and energy profiles of individual ro-vibrational states of molecules in very high rotational states. Recent results will be discussed on the spectroscopy of new rotational states, collisional dynamics in the optical centrifuge, spatially-dependent energy profiles and possibilities for new chemistry induced by centrifugal forces.

  1. Capture into resonance and phase-space dynamics in an optical centrifuge

    Science.gov (United States)

    Armon, Tsafrir; Friedland, Lazar

    2016-04-01

    The process of capture of a molecular ensemble into rotational resonance in the optical centrifuge is investigated. The adiabaticity and phase-space incompressibility are used to find the resonant capture probability in terms of two dimensionless parameters P1 ,2 characterizing the driving strength and the nonlinearity, and related to three characteristic time scales in the problem. The analysis is based on the transformation to action-angle variables and the single resonance approximation, yielding reduction of the three-dimensional rotation problem to one degree of freedom. The analytic results for capture probability are in good agreement with simulations. The existing experiments satisfy the validity conditions of the theory.

  2. The effect of centrifugation speed and time on pre-analytical platelet activation.

    Science.gov (United States)

    Söderström, Anna C; Nybo, Mads; Nielsen, Christian; Vinholt, Pernille J

    2016-12-01

    The results of laboratory analyses are affected by pre-analytical variables, and in particular can platelets be activated by shear handling stress and secrete granular substances. We therefore evaluated the effect of centrifugation speed and time on pre-analytical platelet activation. Citrate- and EDTA-anticoagulated blood from healthy volunteers were centrifuged at 80-10,000 g for 5-15 min to prepare plasma and platelet-rich plasma. Pre-analytical platelet activation was assessed by flow cytometric measurement of platelet P-selectin (CD62p) expression. Blood cell counts, mean platelet volume (MPV), immature platelet fraction (IPF), and platelet distribution width (PDW) were measured. Platelet aggregation in platelet-rich plasma induced by arachidonic acid (AA), ADP or thrombin receptor activator peptide-6 (TRAP) was tested by 96-well aggregometry. The median percentage of platelets expressing P-selectin in citrate- and EDTA-plasma centrifuged at 2000 g for 10 min were 43% [interquartile range (IQR), 38%-53%] and 56% (IQR, 31%-78%), respectively (p=0.82). Platelet-rich plasma prepared at 100-250 g for 10 min had significantly lower platelet P-selectin expression (11%-15%), pcentrifuged. In platelet-rich plasma, increasing centrifugation speed significantly increased platelet yield but decreased contamination from other blood cells, platelet composition was altered as platelet parameters (MPV, IPF, and PDW) was lowered. Platelet aggregation was not affected by the centrifugation speed platelet-rich plasma was prepared. Proportional to centrifugation speed, platelets in plasma and platelet-rich plasma were activated with centrifugation speed, cell content and composition changed while platelet aggregation was unaltered.

  3. Effects of different centrifugation conditions on clinical chemistry and Immunology test results.

    Science.gov (United States)

    Minder, Elisabeth I; Schibli, Adrian; Mahrer, Dagmar; Nesic, Predrag; Plüer, Kathrin

    2011-05-10

    The effect of centrifugation time of heparinized blood samples on clinical chemistry and immunology results has rarely been studied. WHO guideline proposed a 15 min centrifugation time without citing any scientific publications. The centrifugation time has a considerable impact on the turn-around-time. We investigated 74 parameters in samples from 44 patients on a Roche Cobas 6000 system, to see whether there was a statistical significant difference in the test results among specimens centrifuged at 2180 g for 15 min, at 2180 g for 10 min or at 1870 g for 7 min, respectively. Two tubes with different plasma separators (both Greiner Bio-One) were used for each centrifugation condition. Statistical comparisons were made by Deming fit. Tubes with different separators showed identical results in all parameters. Likewise, excellent correlations were found among tubes to which different centrifugation conditions were applied. Fifty percent of the slopes lay between 0.99 and 1.01. Only 3.6 percent of the statistical tests results fell outside the significance level of p < 0.05, which was less than the expected 5%. This suggests that the outliers are the result of random variation and the large number of statistical tests performed. Further, we found that our data are sufficient not to miss a biased test (beta error) with a probability of 0.10 to 0.05 in most parameters. A centrifugation time of either 7 or 10 min provided identical test results compared to the time of 15 min as proposed by WHO under the conditions used in our study.

  4. Experimental Study on Noise Characteristic of Centrifugal Compressor Surge

    OpenAIRE

    Yang, Qichao; Zhao, Yuanyang; SHU, Yue; LI, Xiaosa; LI, Liansheng

    2016-01-01

    The centrifugal air compressor test rig is was designed and established. The experimental study was carried out on the surge characteristics of centrifugal compressor including the pressure in the pipe and the noise characteristics under different rotation speed. The tested results showed that both the suction pressure and discharge pressure fluctuation increase under surge condition and the amplitude of discharge pressure fluctuation is significantly higher than that of suction pressure. In ...

  5. Basic characteristics of centrifuges, (4)

    International Nuclear Information System (INIS)

    Kai, Tsunetoshi

    1977-01-01

    A method of numerically solving the convection-diffusion equation is presented for a binary isotopic gas mixture in the axisymmetric velocity field. A modified Newton's method is employed to perform the numerical integration without the assumptions that the pressure can be estimated from the rigid rotation model and the temperature of gas is uniform. A suitable form of the finite difference equation gives a computationally stable integration with reasonable representation of the molar concentration distribution of isotopic molecules in a rotating cylinder. The method includes a Gaussian elimination procedure which consists of the transformation of the Jacobian matrix to a triangular matrix followed by the backward elimination. Computations are made on UF 6 gas in various centrifuges which have the openings for feed, product and waste on the end plates. Discussions are also presented on gas flows and separative efficiencies for the centrifuges which have baffle plates, skirting plates and bellows. (auth.)

  6. Model tests of geosynthetic reinforced slopes in a geotechnical centrifuge

    International Nuclear Information System (INIS)

    Aklik, P.

    2012-01-01

    Geosynthetic-reinforced slopes and walls became very popular in recent years because of their financial, technical, and ecological advantages. Centrifuge modelling is a powerful tool for physical modelling of reinforced slopes and offers the advantage to observe the failure mechanisms of the slopes. In order to replicate the gravity induced stresses of a prototype structure in a geometrically 1/N reduced model, it is necessary to test the model in a gravitational field N times larger than that of the prototype structure. In this dissertation, geotextile-reinforced slope models were tested in a geotechnical centrifuge to identify the possible failure mechanisms. Slope models were tested by varying slope inclination, tensile strengths of the geotextiles, and overlapping lengths. Photographs of the geotextile reinforced slope models in flight were taken with a digital camera and the soil deformations of geotextile reinforced slopes were evaluated with Particle Image Velocimetry (PIV). The experimental results showed that failure of the centrifuge models initiated at midheight of the slope, and occurred due to geotextile breakage instead of pullout. The location of the shear surface is independent of the tensile strength of the geotextile; it is dependent on the shear strength of the soil. It is logical to see that the required acceleration of the centrifuge at slope failure was decreased with increasing slope inclination. An important contribution to the stability of the slope models was provided by the overlapping of the geotextile layers. It has a secondary reinforcement effect when it was prolonged and passed through the shear surface. Moreover, the location of the shear surface observed with PIV analysis exactly matches the tears of the retrieved geotextiles measured carefully after the centrifuge testing. It is concluded that PIV is an efficient tool to instrument the slope failures in a geotechnical centrifuge.(author) [de

  7. Effect of centrifugation and washing on adipose graft viability: a new method to improve graft efficiency.

    Science.gov (United States)

    Hoareau, Laurence; Bencharif, Karima; Girard, Anne-Claire; Gence, Lydie; Delarue, Pierre; Hulard, Olivier; Festy, Franck; Roche, Regis

    2013-05-01

    Adipose tissue grafting is a promising method in the field of surgical filling. We studied the effect of centrifugation on fat grafts, and we propose an optimised protocol for the improvement of adipose tissue viability. Adipose tissue was subjected to different centrifugations, and the volumes of interstitial liquid and oil released were measured to choose the optimal condition. Tissue from this condition was then compared to tissue obtained from two traditional techniques: strong centrifugation (commonly 3 min at 3000 rpm/900 g), and decantation, by injecting into immunodeficient mice. The cytokine interleukin-6 (IL-6) and chemokine monocyte chemotactic protein-1 (MCP-1) were assayed 24 h post-injection, and after 1 month of grafting the state of the lipografts was evaluated through macroscopic and histological analysis, with oil gap area measurement. Strong centrifugation (900 g, 1800 g) is deleterious for adipose tissue because it leads to until threefold more adipocyte death compared to low centrifugation (100 g, 400 g). In addition, mice injected with strong centrifuged and non-centrifuged adipose tissue have higher rates of blood IL-6 and MCP-1, compared to those grafted with soft centrifuged fat. Moreover, extensive lipid vacuoles were detectable on histological sections of the non-centrifuged lipografts, whereas lipografts from soft centrifugation contain a higher amount of connective tissue containing collagen fibres. It is necessary to wash and centrifuge adipose tissue before reinjection in order to remove infiltration liquid and associated toxic molecules, which in the long term are deleterious for the graft. However, strong centrifugation is not recommended since it leads very quickly to greater adipocyte death. Thus, soft centrifugation (400 g/1 min), preceded by washings, seems to be the most appropriate protocol for the reinjection of adipose tissue. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published

  8. A co-culture system with three different primary human cell populations reveals that biomaterials and MSC modulate macrophage-driven fibroblast recruitment.

    Science.gov (United States)

    Caires, Hugo R; Barros da Silva, Patrícia; Barbosa, Mário A; Almeida, Catarina R

    2018-03-01

    The biological response to implanted biomaterials is a complex and highly coordinated phenomenon involving many different cell types that interact within 3D microenvironments. Here, we increased the complexity of a 3D platform to include at least 3 cell types that play a role in the host response upon scaffold implantation. With this system, it was possible to address how immune responses triggered by 3D biomaterials mediate recruitment of stromal cells that promote tissue regeneration, mesenchymal stromal/stem cells (MSC), or a foreign body response, fibroblasts. Primary human macrophages yielded the highest fibroblast recruitment when interacting with chitosan scaffolds but not polylactic acid. Interestingly, when there were MSC and fibroblasts in the same environment, macrophages in chitosan scaffolds again promoted a significant increase on fibroblast recruitment, but not of MSC. However, macrophages that were firstly allowed to interact with MSC within the scaffolds were no longer able to recruit fibroblasts. This study illustrates the potential to use different scaffolds to regulate the dynamics of recruitment of proregenerative or fibrotic cell types through immunomodulation. Overall, this work strengths the idea that ex vivo predictive systems need to consider the different players involved in the biological response to biomaterials and that timing of arrival of specific cell types will affect the outcome. Copyright © 2017 John Wiley & Sons, Ltd.

  9. Cytoplasmic Domain of MscS Interacts with Cell Division Protein FtsZ: A Possible Non-Channel Function of the Mechanosensitive Channel in Escherichia Coli.

    Directory of Open Access Journals (Sweden)

    Piotr Koprowski

    Full Text Available Bacterial mechano-sensitive (MS channels reside in the inner membrane and are considered to act as emergency valves whose role is to lower cell turgor when bacteria enter hypo-osmotic environments. However, there is emerging evidence that members of the Mechano-sensitive channel Small (MscS family play additional roles in bacterial and plant cell physiology. MscS has a large cytoplasmic C-terminal region that changes its shape upon activation and inactivation of the channel. Our pull-down and co-sedimentation assays show that this domain interacts with FtsZ, a bacterial tubulin-like protein. We identify point mutations in the MscS C-terminal domain that reduce binding to FtsZ and show that bacteria expressing these mutants are compromised in growth on sublethal concentrations of β-lactam antibiotics. Our results suggest that interaction between MscS and FtsZ could occur upon inactivation and/or opening of the channel and could be important for the bacterial cell response against sustained stress upon stationary phase and in the presence of β-lactam antibiotics.

  10. Cytoplasmic Domain of MscS Interacts with Cell Division Protein FtsZ: A Possible Non-Channel Function of the Mechanosensitive Channel in Escherichia Coli.

    Science.gov (United States)

    Koprowski, Piotr; Grajkowski, Wojciech; Balcerzak, Marcin; Filipiuk, Iwona; Fabczak, Hanna; Kubalski, Andrzej

    2015-01-01

    Bacterial mechano-sensitive (MS) channels reside in the inner membrane and are considered to act as emergency valves whose role is to lower cell turgor when bacteria enter hypo-osmotic environments. However, there is emerging evidence that members of the Mechano-sensitive channel Small (MscS) family play additional roles in bacterial and plant cell physiology. MscS has a large cytoplasmic C-terminal region that changes its shape upon activation and inactivation of the channel. Our pull-down and co-sedimentation assays show that this domain interacts with FtsZ, a bacterial tubulin-like protein. We identify point mutations in the MscS C-terminal domain that reduce binding to FtsZ and show that bacteria expressing these mutants are compromised in growth on sublethal concentrations of β-lactam antibiotics. Our results suggest that interaction between MscS and FtsZ could occur upon inactivation and/or opening of the channel and could be important for the bacterial cell response against sustained stress upon stationary phase and in the presence of β-lactam antibiotics.

  11. A vibration model for centrifugal contactors

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, R.A.; Wasserman, M.O.; Wygmans, D.G.

    1992-11-01

    Using the transfer matrix method, we created the Excel worksheet ``Beam`` for analyzing vibrations in centrifugal contactors. With this worksheet, a user can calculate the first natural frequency of the motor/rotor system for a centrifugal contactor. We determined a typical value for the bearing stiffness (k{sub B}) of a motor after measuring the k{sub B} value for three different motors. The k{sub B} value is an important parameter in this model, but it is not normally available for motors. The assumptions that we made in creating the Beam worksheet were verified by comparing the calculated results with those from a VAX computer program, BEAM IV. The Beam worksheet was applied to several contactor designs for which we have experimental data and found to work well.

  12. Läätsa Kalatööstus järjekordne MSC sertifikaadi omanik / Alar Mik

    Index Scriptorium Estoniae

    Mik, Alar

    2014-01-01

    MSC (Marine Stewardship Council)-märgis toodetel tõendab, et tegemist on keskkonnaalaselt vastutustundliku ettevõttega, kelle toodangutsükkel on kala püüdmisest kuni valmistoodangu tarbijani jõudmiseni rangelt seaduslik ja keskkonnasäästlik. Vestlusest ettevõtte juhatuse liikme Toomas Auliga

  13. J-Specific Dynamics in AN Optical Centrifuge Using Transient IR Spectroscopy

    Science.gov (United States)

    Murray, Matthew J.; Liu, Qingnan; Toro, Carlos; Mullin, Amy S.

    2013-06-01

    Quantum state-specific dynamics are reported for a number of CO_{2} rotational states in an optical centrifuge. The optical centrifuge results from combining oppositely-chirped ultrafast laser pulses and spinning CO_{2} molecules into extremely high rotational states with J≈220. Collisions of centrifuged molecules induce depletion of population from low-J states (J=0 and 36) and lead to appearance of population in high J states (J=36, 54 and 76). Transient Doppler-broadened line profiles for individual CO_{2} states reveal that the depletion populations have narrow velocity distributions with translational temperatures significantly colder than 300 K. Molecules that appear in the higher rotational states have broad velocity distributions, showing that both rotational and translational energy are imparted in collisions of the centrifuged molecules. These results show that substantial amounts of angular momentum persist after many collisions and that translational energy exchange continues for several thousand collisions.

  14. Performance improvement of a centrifugal compressor stage by using different vaned diffusers

    International Nuclear Information System (INIS)

    Zhang, Y C; Kong, X Z; Li, F; Sun, W; Chen, Q G

    2013-01-01

    The vaneless diffuser (VLD) is usually adopted in the traditional design of the multi-stage centrifugal compressor because of the stage's match problem. The drawback of the stage with vaneless diffusers is low efficiency. In order to increase the efficiency and at the same time, induce no significant decline in the operating range of the stage, three different types of vaned diffusers are designed and numerically investigated: the traditional vaned diffuser (TVD), the low-solidity cascade diffuser (LSD) and the partial-height vane diffuser (PVD). These three types of vaned diffusers have different influences on the performance of the centrifugal compressor. In the present investigation, the first part investigates the performance of a centrifugal compressor stage with three different vaned diffusers. The second part studies the influences of the height and the position of partial height vanes on the stage performance, and discusses the matching problem between the PVD and the downstream return channel. The stage investigated in this paper includes the impeller, the diffuser, the bend and the return channel. In the process of numerical investigation, the flow is assumed to be steady, and this process includes calculation and simulation. The calculation of 3-D turbulent flow in the stage uses the commercial CFD code NUMECA together with the Spalart-Allmaras turbulence model. The simulation of the computational region includes the impeller passages, the diffuser passages and return channel passages. The structure and surrounding region are assumed to have a perfect cyclic symmetry, so the single channel model and periodic boundary condition are applied at the middle of the passage, that is to reduce the calculation region to only one region. The investigation showed that the low-solidity cascade diffuser would be a better choice as a middle course for the first stage of the multistage centrifugal compressor. Besides, the influences of the height and the position

  15. INFUSION OF THIRD-PARTY MESENCHYMAL STEM CELLS (MSC) AFTER KIDNEY AND LIVER TRANSPLANTATION: A PHASE I-II, OPEN-LABEL, CLINICAL STUDY (EudraCT 2011-001822-81 & NCT01429038)

    OpenAIRE

    DETRY, Olivier; DELBOUILLE, Marie-Hélène; LECHANTEUR, Chantal; SOMJA, Joan; DE ROOVER, Arnaud; WEEKERS, Laurent; SQUIFFLET, Jean-Paul; Honoré, Pierre; DELVENNE, Philippe; MEURISSE, Michel; BAUDOUX, Etienne; BEGUIN, Yves

    2013-01-01

    MSC cells have demonstrated significant immunosuppressive effects in various in vivo and in vitro studies. This study aims to be the first evaluation of the safety and tolerability of third party MSC infusion after cadaveric kidney and liver transplantation in a prospective phase I-II study, taking advantage of our centre expertise and experience in MSC use in graft-versus-host disease (GVHD) after bone marrow transplantation and using an already functioning GMP-compliant laboratory producing...

  16. Container for centrifuging blood

    International Nuclear Information System (INIS)

    Narra, R.K.

    1982-01-01

    A container is described for use in drawing patient's blood, centrifuging the blood and then labelling the separated red cells with sup(99m)Tc. It consists of a tube with a central chamber and a lower portion provided with an aperture in which a weir is supported and extends into the central chamber. The weir has a central channel. A resilient plug seals the aperture. (author)

  17. Effects of centrifugation on transmembrane water loss from normal and pathologic erythrocytes

    International Nuclear Information System (INIS)

    Kaperonis, A.A.; Chien, S.

    1989-01-01

    Plasma 125 I-albumin was used as a marker of extracellular dilution in order to study the effect of high-speed centrifugation on transmembrane water distribution in several types of human red cells, including normal (AA), hemoglobin variants (beta A, AS, SC, beta S, and SS), and those from patients with hereditary spherocytosis. SS and AA erythrocytes were also examined for changes in intracellular hemoglobin concentration of three different density fractions and with increasing duration of spin. The minimum force and duration of centrifugation required to impair water permeability were found to vary with the red cell type, the anticoagulant used (heparin or EDTA), the initial hematocrit of the sample centrifuged, as well as among the individual erythrocyte fractions within the same sample. When subjecting pathologic erythrocytes to high-speed centrifugation, the 125 I-albumin dilution technique can be used to determine whether the centrifugation procedure has led to an artifactual red cell water loss and to correct for this when it does occur. An abnormal membrane susceptibility to mechanical stress was demonstrated in erythrocytes from patients with hereditary spherocytosis and several hemoglobinopathies

  18. Xylem vulnerability to cavitation can be accurately characterised in species with long vessels using a centrifuge method.

    Science.gov (United States)

    Tobin, M F; Pratt, R B; Jacobsen, A L; De Guzman, M E

    2013-05-01

    Vulnerability to cavitation curves describe the decrease in xylem hydraulic conductivity as xylem pressure declines. Several techniques for constructing vulnerability curves use centrifugal force to induce negative xylem pressure in stem or root segments. Centrifuge vulnerability curves constructed for long-vesselled species have been hypothesised to overestimate xylem vulnerability to cavitation due to increased vulnerability of vessels cut open at stem ends that extend to the middle or entirely through segments. We tested two key predictions of this hypothesis: (i) centrifugation induces greater embolism than dehydration in long-vesselled species, and (ii) the proportion of open vessels changes centrifuge vulnerability curves. Centrifuge and dehydration vulnerability curves were compared for a long- and short-vesselled species. The effect of open vessels was tested in four species by comparing centrifuge vulnerability curves for stems of two lengths. Centrifuge and dehydration vulnerability curves agreed well for the long- and short-vesselled species. Centrifuge vulnerability curves constructed using two stem lengths were similar. Also, the distribution of embolism along the length of centrifuged stems matched the theoretical pressure profile induced by centrifugation. We conclude that vulnerability to cavitation can be accurately characterised with vulnerability curves constructed using a centrifuge technique, even in long-vesselled species. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

  19. NECESSARY CONDITIONS OF STABILITY MOVING PARTS OF ROTOR CENTRIFUGE

    OpenAIRE

    Strackeljan, Jens; Babenko, Andriy; Lavrenko, Iaroslav

    2014-01-01

    Design features of modern centrifuges studied. Revealed that their rotors are movable elements that revolve around horizontal axes. The dynamics of these moving parts of laboratory centrifuge considered. Using the Lagrange equation of the second kind the resulting differential equations of their motion considered. The modeling visualization of motion using the software package RecurDyn was made. The results that obtained by the research package RecurDyn and analytically showed that their moti...

  20. Performance and internal flow condition of mini centrifugal pump with splitter blades

    International Nuclear Information System (INIS)

    Shigemitsu, T; Fukutomi, J; Kaji, K; Wada, T

    2012-01-01

    Mini centrifugal pumps having a diameter smaller than 100mm are employed in many fields. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, mini centrifugal pumps with simple structure were investigated by this research. Splitter blades were adopted in this research to improve the performance and the internal flow condition of mini centrifugal pump which had large blade outlet angle. The original impeller without the splitter blades and the impeller with the splitter blades were prepared for an experiment. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on performance and internal flow condition of mini centrifugal pump. On the other hand, a three dimensional steady numerical flow analysis is conducted with the commercial code (ANSYS-CFX) to investigate the internal flow condition in detail. It is clarified from the experimental results that the performance of the mini centrifugal pump is improved by the effect of the splitter blades. The blade-to-blade low velocity regions are suppressed in the case with the splitter blades and the total pressure loss regions are decreased. The effects of the splitter blades on the performance and the internal flow condition are discussed in this paper.

  1. Optimization of flavanones extraction by modulating differential solvent densities and centrifuge temperatures.

    Science.gov (United States)

    Chebrolu, Kranthi K; Jayaprakasha, G K; Jifon, J; Patil, Bhimanagouda S

    2011-07-15

    Understanding the factors influencing flavonone extraction is critical for the knowledge in sample preparation. The present study was focused on the extraction parameters such as solvent, heat, centrifugal speed, centrifuge temperature, sample to solvent ratio, extraction cycles, sonication time, microwave time and their interactions on sample preparation. Flavanones were analyzed in a high performance liquid chromatography (HPLC) and later identified by liquid chromatography and mass spectrometry (LC-MS). The five flavanones were eluted by a binary mobile phase with 0.03% phosphoric acid and acetonitrile in 20 min and detected at 280 nm, and later identified by mass spectral analysis. Dimethylsulfoxide (DMSO) and dimethyl formamide (DMF) had optimum extraction levels of narirutin, naringin, neohesperidin, didymin and poncirin compared to methanol (MeOH), ethanol (EtOH) and acetonitrile (ACN). Centrifuge temperature had a significant effect on flavanone distribution in the extracts. The DMSO and DMF extracts had homogeneous distribution of flavanones compared to MeOH, EtOH and ACN after centrifugation. Furthermore, ACN showed clear phase separation due to differential densities in the extracts after centrifugation. The number of extraction cycles significantly increased the flavanone levels during extraction. Modulating the sample to solvent ratio increased naringin quantity in the extracts. Current research provides critical information on the role of centrifuge temperature, extraction solvent and their interactions on flavanone distribution in extracts. Published by Elsevier B.V.

  2. Applicability of eddy viscosity turbulence models in low specific speed centrifugal pump

    International Nuclear Information System (INIS)

    Wang, Y; Wang, W J

    2012-01-01

    The accuracy of numerical simulation determines the performance prediction whether to be successful or not in the research of centrifugal pump. In order to study the applicability of different turbulence models in the low specific speed centrifugal pump, the object was based on XST45-200 stamping and welding centrifugal pump. Five different kinds of standards which are k-ε model, RNG k-ε model, Realizable k-ε model, Standard k-ω model and SST k-ω model are adopted in steady numerical simulations of the centrifugal pump flow fields. Then, inner and outside characteristics of the centrifugal pump were gotten .And it also provides the calculation of pressure distribution using different turbulence models in the five conditions. Lastly, the performance curves of head, power and efficiency are compared with the test. The results show a good agreement between five kinds of turbulence models and tests obtained in small flow and design condition. In large flow, the standard k-ε model is worse than the other four, which is larger than the tested head with a relative deviation of 47.9% and efficiency with 50%.The calculation accuracy which used RNG k-ε model is highest. SST k-ω model takes the second place. Standard k-ω model can be used for the numerical simulation in the low specific speed centrifugal pump.

  3. The Effect of Moment of Inertia on the Liquids in Centrifugal Microfluidics

    Directory of Open Access Journals (Sweden)

    Esmail Pishbin

    2016-12-01

    Full Text Available The flow of liquids in centrifugal microfluidics is unidirectional and dominated by centrifugal and Coriolis forces (i.e., effective only at T-junctions. Developing mechanisms and discovering efficient techniques to propel liquids in any direction other than the direction of the centrifugal force has been the subject of a large number of studies. The capillary force attained by specific surface treatments, pneumatic energy, active and passive flow reciprocation and Euler force have been previously introduced in order to manipulate the liquid flow and push it against the centrifugal force. Here, as a new method, the moment of inertia of the liquid inside a chamber in a centrifugal microfluidic platform is employed to manipulate the flow and propel the liquid passively towards the disc center. Furthermore, the effect of the moment of inertia on the liquid in a rectangular chamber is evaluated, both in theory and experiments, and the optimum geometry is defined. As an application of the introduced method, the moment of inertia of the liquid is used in order to mix two different dyed deionized (DI waters; the mixing efficiency is evaluated and compared to similar mixing techniques. The results show the potential of the presented method for pumping liquids radially inward with relatively high flow rates (up to 23 mm3/s and also efficient mixing in centrifugal microfluidic platforms.

  4. Droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling for simpler and faster PCR assay using wire-guided manipulations

    Directory of Open Access Journals (Sweden)

    You David J

    2012-09-01

    Full Text Available Abstract A computer numerical control (CNC apparatus was used to perform droplet centrifugation, droplet DNA extraction, and rapid droplet thermocycling on a single superhydrophobic surface and a multi-chambered PCB heater. Droplets were manipulated using “wire-guided” method (a pipette tip was used in this study. This methodology can be easily adapted to existing commercial robotic pipetting system, while demonstrated added capabilities such as vibrational mixing, high-speed centrifuging of droplets, simple DNA extraction utilizing the hydrophobicity difference between the tip and the superhydrophobic surface, and rapid thermocycling with a moving droplet, all with wire-guided droplet manipulations on a superhydrophobic surface and a multi-chambered PCB heater (i.e., not on a 96-well plate. Serial dilutions were demonstrated for diluting sample matrix. Centrifuging was demonstrated by rotating a 10 μL droplet at 2300 round per minute, concentrating E. coli by more than 3-fold within 3 min. DNA extraction was demonstrated from E. coli sample utilizing the disposable pipette tip to cleverly attract the extracted DNA from the droplet residing on a superhydrophobic surface, which took less than 10 min. Following extraction, the 1500 bp sequence of Peptidase D from E. coli was amplified using rapid droplet thermocycling, which took 10 min for 30 cycles. The total assay time was 23 min, including droplet centrifugation, droplet DNA extraction and rapid droplet thermocycling. Evaporation from of 10 μL droplets was not significant during these procedures, since the longest time exposure to air and the vibrations was less than 5 min (during DNA extraction. The results of these sequentially executed processes were analyzed using gel electrophoresis. Thus, this work demonstrates the adaptability of the system to replace many common laboratory tasks on a single platform (through re-programmability, in rapid succession (using droplets

  5. Centrifuge modeling of one-step outflow tests for unsaturated parameter estimations

    Directory of Open Access Journals (Sweden)

    H. Nakajima

    2006-01-01

    Full Text Available Centrifuge modeling of one-step outflow tests were carried out using a 2-m radius geotechnical centrifuge, and the cumulative outflow and transient pore water pressure were measured during the tests at multiple gravity levels. Based on the scaling laws of centrifuge modeling, the measurements generally showed reasonable agreement with prototype data calculated from forward simulations with input parameters determined from standard laboratory tests. The parameter optimizations were examined for three different combinations of input data sets using the test measurements. Within the gravity level examined in this study up to 40g, the optimized unsaturated parameters compared well when accurate pore water pressure measurements were included along with cumulative outflow as input data. With its capability to implement variety of instrumentations under well controlled initial and boundary conditions and to shorten testing time, the centrifuge modeling technique is attractive as an alternative experimental method that provides more freedom to set inverse problem conditions for the parameter estimation.

  6. Centrifuge modeling of one-step outflow tests for unsaturated parameter estimations

    Science.gov (United States)

    Nakajima, H.; Stadler, A. T.

    2006-10-01

    Centrifuge modeling of one-step outflow tests were carried out using a 2-m radius geotechnical centrifuge, and the cumulative outflow and transient pore water pressure were measured during the tests at multiple gravity levels. Based on the scaling laws of centrifuge modeling, the measurements generally showed reasonable agreement with prototype data calculated from forward simulations with input parameters determined from standard laboratory tests. The parameter optimizations were examined for three different combinations of input data sets using the test measurements. Within the gravity level examined in this study up to 40g, the optimized unsaturated parameters compared well when accurate pore water pressure measurements were included along with cumulative outflow as input data. With its capability to implement variety of instrumentations under well controlled initial and boundary conditions and to shorten testing time, the centrifuge modeling technique is attractive as an alternative experimental method that provides more freedom to set inverse problem conditions for the parameter estimation.

  7. Centrifugal compressor fault diagnosis based on qualitative simulation and thermal parameters

    Science.gov (United States)

    Lu, Yunsong; Wang, Fuli; Jia, Mingxing; Qi, Yuanchen

    2016-12-01

    This paper concerns fault diagnosis of centrifugal compressor based on thermal parameters. An improved qualitative simulation (QSIM) based fault diagnosis method is proposed to diagnose the faults of centrifugal compressor in a gas-steam combined-cycle power plant (CCPP). The qualitative models under normal and two faulty conditions have been built through the analysis of the principle of centrifugal compressor. To solve the problem of qualitative description of the observations of system variables, a qualitative trend extraction algorithm is applied to extract the trends of the observations. For qualitative states matching, a sliding window based matching strategy which consists of variables operating ranges constraints and qualitative constraints is proposed. The matching results are used to determine which QSIM model is more consistent with the running state of system. The correct diagnosis of two typical faults: seal leakage and valve stuck in the centrifugal compressor has validated the targeted performance of the proposed method, showing the advantages of fault roots containing in thermal parameters.

  8. New design centrifugal contactor remotely controlled for solvent extraction operations for feed clarification

    International Nuclear Information System (INIS)

    Candelieri, T.; Gerardi, A.; Petrigliano, G.; Siepe, V.

    1987-01-01

    The project concept of the nuclear facilities has gone through an important evolution in the past years in relation to the need of: garantiing the remote maintenance reducing workers exposure when operating in high-risk areas; making easier final decommissioning operations of the plants. In this way the ITREC pilot plant (built in 1970s') for its modular characteristic based on Rack Removal System (R.R.S.) was the first example of this new concept of project. A further development, in the field of remote maintenance and decommissioning operations, we can obtain associating to the R.R.S. concept that of projecting the single components (only for the critical ones) remotely demountable in their higher radioactive parts to consent the maintenance-substitution and/or decommissioning operations without interfering with remaining parts of the plant which it is connected. All of this helps in the realization of the aim making better plant operations reducing drastically work time and therefore non-functioning period of the plants. These principles have been applicated in the realization of two important components in reprocessing plant: the centrifugal contactor for solvent extraction and feed clarification centrifuge

  9. Centrifuge: rapid and sensitive classification of metagenomic sequences.

    Science.gov (United States)

    Kim, Daehwan; Song, Li; Breitwieser, Florian P; Salzberg, Steven L

    2016-12-01

    Centrifuge is a novel microbial classification engine that enables rapid, accurate, and sensitive labeling of reads and quantification of species on desktop computers. The system uses an indexing scheme based on the Burrows-Wheeler transform (BWT) and the Ferragina-Manzini (FM) index, optimized specifically for the metagenomic classification problem. Centrifuge requires a relatively small index (4.2 GB for 4078 bacterial and 200 archaeal genomes) and classifies sequences at very high speed, allowing it to process the millions of reads from a typical high-throughput DNA sequencing run within a few minutes. Together, these advances enable timely and accurate analysis of large metagenomics data sets on conventional desktop computers. Because of its space-optimized indexing schemes, Centrifuge also makes it possible to index the entire NCBI nonredundant nucleotide sequence database (a total of 109 billion bases) with an index size of 69 GB, in contrast to k-mer-based indexing schemes, which require far more extensive space. © 2016 Kim et al.; Published by Cold Spring Harbor Laboratory Press.

  10. Centrifugal vacuum casting for fuel cladding tube blanks

    International Nuclear Information System (INIS)

    Zelenskii, V.F.; Neklyudov, I.M.; Chernyi, B.P.; Zeidlits, M.P.; Vanzha, A.F.; Rubashko, V.G.; Ryabchikov, L.N.; Smirnov, Y.K.; Bespalova, V.R.; Mashkarova, V.T.; Rybal'chenko, N.D.

    1990-01-01

    An advanced technique for making tube blanks with an acceptable level of nonmetallic inclusions is vacuum induction melting combined with centrifugal casting, as the latter gives a cylindrical casting having an axial hole, while the cast metal has elevated density and contains fewer nonmetallic inclusions than does the metal cast in a stationary mold. The reduction in the nonmetallic inclusions occurs because of increased rates of floating up in the rotating mold on account of the centrifugal force and the rejection to the inner surface. One can choose the parameters such as the pouring speed, rotational speed, mold cooling, and liquid-metal temperature and can introduce a deoxidizer to remove the nonmetallic inclusions or reduce the grain size of them and produce an appropriate cast structure and obtain a metal whose quality is the same as that on vacuum induction melting with secondary arc remelting. For these purposes, the authors have developed centrifugal-casting machines for use under vacuum or in inert gases with horizontal and vertical mold rotation axes

  11. Simulations of overall flow in gas centrifuge considering feed jet

    International Nuclear Information System (INIS)

    He Liang; Jiang Dongjun; Ying Chuntong

    2010-01-01

    A coupled method for the numerical solution of the flow in rapidly rotating gas centrifuge was presented. An iteration process of DSMC and CFD was performed to analyze the overall flow in radial direction, in which DSMC was adopted to simulate the rarefied region, and CFD was adopted to the counter-current of gas centrifuge to discrete the model equations. It was applied to simulate the 2D symmetrical flow model considering the rarefied region with the feed jet flow. A series of illustrative numerical examples were given. The flow structures of the feed jet in the rarefied gas flow region were shown. The results suggest that DSMC CFD coupled method is competent to the simulations of overall flow in a gas centrifuge. (authors)

  12. Centrifugal gas separator

    Energy Technology Data Exchange (ETDEWEB)

    Kanagawa, A; Fujii, O; Nakamoto, H

    1970-03-09

    Counter currents in the rotary drum of a centrifugal gas separator are produced by providing, at either end of the drum in the vicinity of the circumferential and central positions, respectively, outflow and inflow holes with a communicating passage external to the drum there between whereby gaseous counter currents are caused to flow within the drum and travel through the passage which is provided with gas flow adjustment means. Furthermore, the space defined by the stationary portion of the passage and the rotor drum is additionally provided with a screw pump or throttling device at either its stationary side or drum side or both in order to produce a radially directed gas flow therewithin. A gas mixture is axially admitted into the drum while centrifugal force and a cooling element provided therebelow cause an increase in gas pressure along and a gaseous flow toward the wall member, whereupon the comparatively high pressured circumferentially distributed gas is extracted from the outlet holes, flows through the external gas passage and back into the lower pressured drum core through the inlet holes, thus producing the desired counter currents. The gases thus separated are withdrawn along axially provided discharge pipes. Accordingly, this invention permits heating elements which were formerly used to produce thermal convection currents to be disposed of and allows the length of the rotor drum to be more efficiently utilized to enhance separation efficiency.

  13. Capture into resonance and phase space dynamics in optical centrifuge

    Science.gov (United States)

    Armon, Tsafrir; Friedland, Lazar

    2016-05-01

    The process of capture of a molecular enesemble into rotational resonance in the optical centrifuge is investigated. The adiabaticity and phase space incompressibility are used to find the resonant capture probability in terms of two dimensionless parameters P1 , 2 characterising the driving strength and the nonlinearity, and related to three characteristic time scales in the problem. The analysis is based on the transformation to action-angle variables and the single resonance approximation, yielding reduction of the three-dimensional rotation problem to one degree of freedom. The analytic results for capture probability are in a good agreement with simulations. The existing experiments satisfy the validity conditions of the theory. This work was supported by the Israel Science Foundation Grant 30/14.

  14. Spin doctors: new innovations for centrifugal apheresis.

    Science.gov (United States)

    Kambic, H E; Nosé, Y

    1997-08-01

    The preparation of plasma from blood has a long history dating back to the early 1900s when the concept of blood washing replaced the traditional blood letting. Over the next 57 years landmark discoveries such as centrifugal and membrane filtration systems led to different and rapid plasma, solute, and cell separation. These were not singular events but rather events influenced by the converging chemical, physiological, and engineering advances that have characterized the latter half of the 20th century. These events have led to entire new fields of biomedical research. The biotechnology for on-line plasma separation and plasma treatment has opened a new era, expanding the application of extracorporeal technology to modern therapeutic medicine. The association of biochemical or cellular abnormalities with various disease states provides the rationale for therapeutic plasma exchange (the removal of large amounts of patient's plasma, alone or with replacement with crystalloid) and therapeutic cytopheresis (removal of cellular elements). The purpose of this review is to provide a historical picture of the innovative ideas of the spin doctors and their devices, which predate the centrifugal blood and cell separators commonplace to any hospital or blood bank worldwide. The emphasis is to define the historical events and their impacts on the development of centrifugal devices and apheresis technologies.

  15. Protein removal from waste brines generated during ham salting through acidification and centrifugation.

    Science.gov (United States)

    Gutiérrez-Martínez, Maria del Rosario; Muñoz-Guerrero, Hernán; Alcaína-Miranda, Maria Isabel; Barat, José Manuel

    2014-03-01

    The salting step in food processes implies the production of large quantities of waste brines, having high organic load, high conductivity, and other pollutants with high oxygen demand. Direct disposal of the residual brine implies salinization of soil and eutrophication of water. Since most of the organic load of the waste brines comes from proteins leaked from the salted product, precipitation of dissolved proteins by acidification and removal by centrifugation is an operation to be used in waste brine cleaning. The aim of this study is optimizing the conditions for carrying out the separation of proteins from waste brines generated in the pork ham salting operation, by studying the influence of pH, centrifugal force, and centrifugation time. Models for determining the removal of proteins depending on the pH, centrifugal force, and time were obtained. The results showed a high efficacy of the proposed treatment for removing proteins, suggesting that this method could be used for waste brine protein removal. The best pH value to be used in an industrial process seems to be 3, while the obtained results indicate that almost 90% of the proteins from the brine can be removed by acidification followed by centrifugation. A further protein removal from the brine should have to be achieved using filtrating techniques, which efficiency could be highly improved as a consequence of the previous treatment through acidification and centrifugation. Waste brines from meat salting have high organic load and electrical conductivity. Proteins can be removed from the waste brine by acidification and centrifugation. The total protein removal can be up to 90% of the initial content of the waste brine. Protein removal is highly dependent on pH, centrifugation rate, and time. © 2014 Institute of Food Technologists®

  16. Laser tracker TSPI uncertainty quantification via centrifuge trajectory

    Science.gov (United States)

    Romero, Edward; Paez, Thomas; Brown, Timothy; Miller, Timothy

    2009-08-01

    Sandia National Laboratories currently utilizes two laser tracking systems to provide time-space-position-information (TSPI) and high speed digital imaging of test units under flight. These laser trackers have been in operation for decades under the premise of theoretical accuracies based on system design and operator estimates. Advances in optical imaging and atmospheric tracking technology have enabled opportunities to provide more precise six degree of freedom measurements from these trackers. Applying these technologies to the laser trackers requires quantified understanding of their current errors and uncertainty. It was well understood that an assortment of variables contributed to laser tracker uncertainty but the magnitude of these contributions was not quantified and documented. A series of experiments was performed at Sandia National Laboratories large centrifuge complex to quantify TSPI uncertainties of Sandia National Laboratories laser tracker III. The centrifuge was used to provide repeatable and economical test unit trajectories of a test-unit to use for TSPI comparison and uncertainty analysis. On a centrifuge, testunits undergo a known trajectory continuously with a known angular velocity. Each revolution may represent an independent test, which may be repeated many times over for magnitudes of data practical for statistical analysis. Previously these tests were performed at Sandia's rocket sled track facility but were found to be costly with challenges in the measurement ground truth TSPI. The centrifuge along with on-board measurement equipment was used to provide known ground truth position of test units. This paper discusses the experimental design and techniques used to arrive at measures of laser tracker error and uncertainty.

  17. Centrifugal-reciprocating compressor

    Science.gov (United States)

    Higa, W. H. (Inventor)

    1984-01-01

    A centrifugal compressor is described which includes at least one pair of cylinders arranged in coaxial alignment and supported for angular displacement about a common axis of rotation normally disecting a common longitudinal axis of symmetry for the cylinders. The cylinders are characterized by ported closures located at the mutually remote ends thereof through which the cylinders are charged and discharged, and a pair of piston heads seated within the cylinders and supported for floating displacement in compressive strokes in response to unidirectional angular displacement imparted to the cylinders.

  18. Cyber meets nuclear - Stuxnet and the cyberattacks on Iranian centrifuges

    Energy Technology Data Exchange (ETDEWEB)

    Englert, Matthias [IANUS, TU Darmstadt (Germany)

    2013-07-01

    In 2010 the computer worm Stuxnet attacked the information hardware of the Iranian uranium enrichment program. Stuxnet spread by USB flash drives and attacked SCADA software installed on Windows systems via several zero-day exploits. SCADA configures programmable logic controllers which control in the case of the Iranian centrifuge cascades frequency converter drives to choose the frequency of centrifuge motors. Thus the attackers were able to either change the rotation frequency of the rotor and thereby the separative power of the centrifuge or even destroy the fast spinning centrifuges by stopping and restarting them. The designers of Stuxnet must have had intimate knowledge of the facility design as e.g. the cascade connection scheme was programmed into Stuxnet. Based on this information some calculations of the Iranian cascade regarding the potential to produce highly enriched uranium will be presented using cascade simulation tools. The use of such highly sophisticated computer attacks to sabotage a nuclear program shed a new light on the debate about cyber attacks and the use of information technology for kinetic attacks in general. The talk will address problems the weaponization of information technology poses for international security and will highlight some more recent developments.

  19. Numerical and experimental analysis of the sedimentation of spherical colloidal suspensions under centrifugal force

    Science.gov (United States)

    Antonopoulou, Evangelia; Rohmann-Shaw, Connor F.; Sykes, Thomas C.; Cayre, Olivier J.; Hunter, Timothy N.; Jimack, Peter K.

    2018-03-01

    Understanding the sedimentation behaviour of colloidal suspensions is crucial in determining their stability. Since sedimentation rates are often very slow, centrifugation is used to expedite sedimentation experiments. The effect of centrifugal acceleration on sedimentation behaviour is not fully understood. Furthermore, in sedimentation models, interparticle interactions are usually omitted by using the hard-sphere assumption. This work proposes a one-dimensional model for sedimentation using an effective maximum volume fraction, with an extension for sedimentation under centrifugal force. A numerical implementation of the model using an adaptive finite difference solver is described. Experiments with silica suspensions are carried out using an analytical centrifuge. The model is shown to be a good fit with experimental data for 480 nm spherical silica, with the effects of centrifugation at 705 rpm studied. A conversion of data to Earth gravity conditions is proposed, which is shown to recover Earth gravity sedimentation rates well. This work suggests that the effective maximum volume fraction accurately captures interparticle interactions and provides insights into the effect of centrifugation on sedimentation.

  20. Numerical identification of blade exit angle effect on the performance for a multistage centrifugal pump impeller

    Directory of Open Access Journals (Sweden)

    Babayigit Osman

    2015-01-01

    Full Text Available Nowadays, single and multistage centrifugal pumps are widely used in industrial and mining enterprises. One of the most important components of a centrifugal pump is the impeller. The performance characteristics are related to the pump comprising the head and the overall efficiency rely a great deal on the impeller geometry. In this work, effects of blade exit angle change on hydraulic efficiency of a multi stage pump impeller are investigated via Ansys-Fluent computational fluid dynamics software for constant width impeller entrance and exit gates, blade numbers and blade thickness. Firstly, the flow volume of a centrifugal pump impeller is generated and then mesh structure is formed for the full impeller flow volume. Secondly, rotational periodic flow model are adopted in order to examine the effect of periodic flow assumption on the performance predictions. Corresponding to the available experimental data, inlet mass flow rate, outlet static pressure and rotation of impeller are taken as 0.02m3s-1, 450 kPa and 2950 rpm, respectively for the water fluid. No slip boundary condition is exposed to all solid of surface in the flow volume. The continuity and Navier-Stokes equations with the k-ε turbulence model and the standard wall functions are used. During the study, numerical analyses are conducted for the blade exit angle values of 18°, 20°, 25°, 30° and 35°. In consequence of the performed analyses, it is determined that hydraulic efficiency of the pump impeller value is changed between 81.0-84.6%. The most convenient blade exit angle that yields 84.6% hydraulic efficiency at is 18°. The obtained results show that the blade exit angle range has an impact on the centrifugal pump performance describing the pump head and the hydraulic efficiency.

  1. Solidified structure of thin-walled titanium parts by vertical centrifugal casting

    Directory of Open Access Journals (Sweden)

    Wu Shiping

    2011-05-01

    Full Text Available The solidified structure of the thin-walled and complicated Ti-6Al-4V castings produced by the vertical centrifugal casting process was studied in the present work. The results show that the wall thickness of the section is featured with homogeneously distributed fine equiaxial grains, compared with the microstructure of the thick-walled section. The grain size of the castings has a tendency to decrease gradually with the increasing of the centrifugal radius. The inter-lamellar space in thick-walled casting parts is bigger than that of the thin-walled parts, and the profile of inter-lamellar space is not susceptible to the centrifugal radius.

  2. Experiments with background gas in a vacuum arc centrifuge

    International Nuclear Information System (INIS)

    Dallaqua, R.S.; Simpson, S.W.; Del Bosco, E.

    1996-01-01

    Since promising isotope separation results were first reported by Krishnan et al. in 1981, a range of vacuum arc centrifuge experiments have been conducted in laboratories around the world. The PCEN (Plasma CENtrifuge) vacuum arc centrifuge at the Brazilian National Institute for Space Research has been used for isotope separation studies with cathode materials of carbon and magnesium and also to investigate the performance in terms of the rotational velocity attained for different cathode materials. Here, a vacuum arc centrifuge has been operated with an initial filling gas of either argon or hydrogen for pressures ranging from 10 -3 to 10 -1 Pa. The angular velocity ω of the plasma has been determined by cross-correlating the signals from potential probes, and the electron temperature T has been deduced from Langmuir probe data. At high gas pressures and early times during the 14 ms plasma lifetime, high-frequency nonuniformities frequently observed in the vacuum discharge disappear, suggesting that the associated instability is suppressed. Under the same conditions, nonuniformities rotating with much lower angular velocities are observed in the plasma. Temperatures are reduced in the presence of the background gas, and the theoretical figure of merit for separation proportional to ω 2 /T is increased compared to its value in the vacuum discharge for both argon and hydrogen gas fillings

  3. Why have we stopped research on liquid centrifugal separation

    International Nuclear Information System (INIS)

    Li, N.

    1996-01-01

    Using high-temperature high-speed liquid centrifuges for lanthanides and actinides separation was originally proposed as a physical separation method in the Los Alamos ADTT/ATW concept [C. Bowman, LA-UR-92-1065 (1992)]. The authors investigated centrifugal separation in a concerted effort of experiments, theoretical analysis and numerical simulations. They discovered that owing to the ionic-composition-dependence of the sedimentation coefficients for the fission products and actinides, separation by grouping of molecular densities would not work in general in the molten salt environment. Alternatively the lanthanides and actinides could be transferred to a liquid metal carrier (e.g. bismuth) via reductive extraction and then separated by liquid centrifuges, but the material and technical challenges are severe. Meanwhile the authors have established that the reductive extraction procedure itself can be used for desired separations. Unlike conventional aqueous-based reprocessing technologies, reductive extraction separation uses only reagent (Li) that reconstitutes carrier salts (LiF-BeF 2 ) and a processing medium (Bi) that can be continuously recycled and reused, with a nearly-pure fission products waste stream. The processing units are compact and reliable, and can be built at relatively low cost while maintaining high throughput. Therefore the research effort on developing liquid centrifuges for separations in ADTT/ATW was terminated in late 1995. This paper will discuss the various aspects involved in reaching this decision

  4. An Investigation of Backflow Phenomenon in Centrifugal Compressors

    Science.gov (United States)

    Benser, William A; Moses, Jason J

    1945-01-01

    Report presents the results of an investigation conducted to determine the nature and the extent of the reversal of flow, which occurs at the inlet of centrifugal compressors over a considerable portion of the operating range. Qualitative studies of this flow reversal were made by lampblack patterns taken on a mixed-flow-type impeller and by tuft studies made on a conventional centrifugal compressor. Quantitative studies were made on a compressor specially designed to enable survey of angularity of flow, static and total pressures, and temperatures to be taken very close to the impeller front housing.

  5. Centrifuge modelling of a laterally cyclic loaded pile

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte; Leth, Caspar Thrane; Hededal, Ole

    2010-01-01

    A total number of 9 static and 6 cyclic centrifuge tests on laterally loaded piles in very dense, dry sand was erformed. The prototype dimensions of the piles were 1 meter in diameter and penetration depths varying from 6 to 10 meters. The static tests were used to investigate the initial subgrade...... reaction modulus and as a reference for cyclic tests. For the cyclic tests the accumulation of deflections and the change in secant stiffness of the soil from repetitive loading were investigated. From all the tests carried out accumulations of deflections were seen. rom the centrifuge tests it was seen...

  6. High-speed centrifugation induces aggregation of extracellular vesicles.

    Science.gov (United States)

    Linares, Romain; Tan, Sisareuth; Gounou, Céline; Arraud, Nicolas; Brisson, Alain R

    2015-01-01

    Plasma and other body fluids contain cell-derived extracellular vesicles (EVs), which participate in physiopathological processes and have potential biomedical applications. In order to isolate, concentrate and purify EVs, high-speed centrifugation is often used. We show here, using electron microscopy, receptor-specific gold labelling and flow cytometry, that high-speed centrifugation induces the formation of EV aggregates composed of a mixture of EVs of various phenotypes and morphologies. The presence of aggregates made of EVs of different phenotypes may lead to erroneous interpretation concerning the existence of EVs harbouring surface antigens from different cell origins.

  7. High-speed centrifugation induces aggregation of extracellular vesicles

    Directory of Open Access Journals (Sweden)

    Romain Linares

    2015-12-01

    Full Text Available Plasma and other body fluids contain cell-derived extracellular vesicles (EVs, which participate in physiopathological processes and have potential biomedical applications. In order to isolate, concentrate and purify EVs, high-speed centrifugation is often used. We show here, using electron microscopy, receptor-specific gold labelling and flow cytometry, that high-speed centrifugation induces the formation of EV aggregates composed of a mixture of EVs of various phenotypes and morphologies. The presence of aggregates made of EVs of different phenotypes may lead to erroneous interpretation concerning the existence of EVs harbouring surface antigens from different cell origins.

  8. Isolation of Mycobacterium chelonei with the lysis-centrifugation blood culture technique.

    OpenAIRE

    Fojtasek, M F; Kelly, M T

    1982-01-01

    Mycobacterium chelonei was isolated from a patient by the lysis-centrifugation and the conventional two-bottle blood culture methods. The lysis-centrifugation method was significantly more sensitive and rapid than the conventional method in detecting and isolating this organism; quantitations done by this method were useful for monitoring response to therapy.

  9. Effects of centrifugation on transmembrane water loss from normal and pathologic erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Kaperonis, A.A.; Chien, S.

    1989-02-01

    Plasma /sup 125/I-albumin was used as a marker of extracellular dilution in order to study the effect of high-speed centrifugation on transmembrane water distribution in several types of human red cells, including normal (AA), hemoglobin variants (beta A, AS, SC, beta S, and SS), and those from patients with hereditary spherocytosis. SS and AA erythrocytes were also examined for changes in intracellular hemoglobin concentration of three different density fractions and with increasing duration of spin. The minimum force and duration of centrifugation required to impair water permeability were found to vary with the red cell type, the anticoagulant used (heparin or EDTA), the initial hematocrit of the sample centrifuged, as well as among the individual erythrocyte fractions within the same sample. When subjecting pathologic erythrocytes to high-speed centrifugation, the /sup 125/I-albumin dilution technique can be used to determine whether the centrifugation procedure has led to an artifactual red cell water loss and to correct for this when it does occur. An abnormal membrane susceptibility to mechanical stress was demonstrated in erythrocytes from patients with hereditary spherocytosis and several hemoglobinopathies.

  10. Optimizing platelet-rich plasma gel formation by varying time and gravitational forces during centrifugation.

    Science.gov (United States)

    Jo, Chris H; Roh, Young Hak; Kim, Ji Eun; Shin, Sue; Yoon, Kang Sup

    2013-10-01

    Despite the increasing clinical use of topical platelet-rich plasma (PRP) to enhance tissue healing and regeneration, there is no properly standardized method of autologous PRP gel preparation. This study examined the effect of the centrifugation time and gravitational force (g) on the platelet recovery ratio of PRP and determined the most effective centrifugation conditions for preparing PRP. Two-step centrifugations for preparing PRP were used in 39 subjects who had consented prior to the study's start. The separating centrifugation (Step 1, used to separate whole blood into its two main components: red blood cells and plasma) was tested from 500g to 1900g at 200g increments for 5 minutes (min), and from 100g to 1300g at 200g increments for 10 minutes. After separating centrifugation, upper plasma layer was transferred to another plain tube for the condensation centrifugation and remaining lower cell layer was discarded. The condensation centrifugation (Step 2, used to condense the platelets in the separated plasma) was tested at 1000g for 15 min, 1500g for 15 min, 2000g for 5 min and 3000g for 5 min, additionally at 1000g for 10 min and 1500g for 10 min. Platelet gelation was induced by adding 10% calcium gluconate to final PRP with volume ratio of 1:10. The optimal separating centrifugation conditions were followed by 900g for 5 minutes and the condensation conditions were followed by 1500g for 15 minutes, of which recovery ratios were 92.0 ± 3.1% and 84.3 ± 10.0%, respectively.

  11. Life Sciences Centrifuge Facility assessment

    Science.gov (United States)

    Benson, Robert H.

    1994-01-01

    This report provides an assessment of the status of the Centrifuge Facility being developed by ARC for flight on the International Space Station Alpha. The assessment includes technical status, schedules, budgets, project management, performance of facility relative to science requirements, and identifies risks and issues that need to be considered in future development activities.

  12. Basic characteristics of a low uranium enrichment cascade by centrifugation, (2)

    International Nuclear Information System (INIS)

    Kai, Tsunetoshi

    1975-01-01

    The theory for a cascade of centrifuges described in the preceding report of the same general title is further developed. First, equations describing the distributions of the flow and the mole concentration are derived from the material balance relations for a square cascade. Corresponding equations are next obtained to cover a squared-off cascade consisting of a series of square cascades. A computer program is outlined which makes it possible to obtain the shape of the most efficient squared-off cascade. The efficiency of the current form of squared-off centrifuge cascade with reflux pipes is found to be lower than obtainable with gaseous diffusion. The efficiency can be improved by the adoption of a tapered squared-off cascade with centrifuges provided with eccentric cuts to take the place of reflux pipes. The dynamic characteristics are also discussed. Analysis of the start-up behavior reveals that the equilibrium time of the centrifuge cascade is much shorter than for a coresponding gaseous diffusion cascade, and that the mole concentration of the product rapidly rises to attain steady state condition. It is also found that even when the feed flow rate fluctuates, the mole concentration of the product is relatively stable. The effect of a centrifuge failure in the cascade is examined. The optimum mole concentration for the waste effluent discarded from the cascade is calculated from the viewpoint of cost. (auth.)

  13. Fibrous hyaluronic acid hydrogels that direct MSC chondrogenesis through mechanical and adhesive cues.

    Science.gov (United States)

    Kim, Iris L; Khetan, Sudhir; Baker, Brendon M; Chen, Christopher S; Burdick, Jason A

    2013-07-01

    Electrospinning has recently gained much interest due to its ability to form scaffolds that mimic the nanofibrous nature of the extracellular matrix, such as the size and depth-dependent alignment of collagen fibers within hyaline cartilage. While much progress has been made in developing bulk, isotropic hydrogels for tissue engineering and understanding how the microenvironment of such scaffolds affects cell response, these effects have not been extensively studied in a nanofibrous system. Here, we show that the mechanics (through intrafiber crosslink density) and adhesivity (through RGD density) of electrospun hyaluronic acid (HA) fibers significantly affect human mesenchymal stem cell (hMSC) interactions and gene expression. Specifically, hMSC spreading, proliferation, and focal adhesion formation were dependent on RGD density, but not on the range of fiber mechanics investigated. Moreover, traction-mediated fiber displacements generally increased with more adhesive fibers. The expression of chondrogenic markers, unlike trends in cell spreading and cytoskeletal organization, was influenced by both fiber mechanics and adhesivity, in which softer fibers and lower RGD densities generally enhanced chondrogenesis. This work not only reveals concurrent effects of mechanics and adhesivity in a fibrous context, but also highlights fibrous HA hydrogels as a promising scaffold for future cartilage repair strategies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. MSC/NASTRAN ''expert'' techniques developed and applied to the TFTR poloidal field coils

    International Nuclear Information System (INIS)

    O'Toole, J.A.

    1986-01-01

    The TFTR poloidal field (PF) coils are being analyzed by PPPL and Grumman using MSC/NASTRAN as a part of an overall effort to establish the absolute limiting conditions of operation for TFTR. Each of the PF coils will be analyzed in depth, using a detailed set of finite element models. Several of the models developed are quite large because each copper turn, as well as its surrounding insulation, was modeled using solid elements. Several of the finite element models proved large enough to tax the capabilities of the National Magnetic Fusion Energy Computer Center (NMFECC), specifically disk storage space. To allow the use of substructuring techniques with their associated data bases for the larger models, it became necessary to employ certain infrequently used MSC/NASTRAN ''expert'' techniques. The techniques developed used multiple data bases and data base sets to divide each problem into a series of computer runs. For each run, only the data required was kept on active disk space, the remainder being placed in inactive ''FILEM'' storage, thus, minimizing active disk space required at any time and permitting problem solution using the NMFECC. A representative problem using the TFTR OH-1 coil global model provides an example of the techniques developed. The special considerations necessary to obtain proper results are discussed

  15. Solid deuterium centrifuge pellet injector

    International Nuclear Information System (INIS)

    Foster, C.A.

    1982-01-01

    Pellet injectors are needed to fuel long pulse tokamak plasmas and other magnetic confinement devices. For this purpose, an apparatus has been developed that forms 1.3-mm-diam pellets of frozen deuterium at a rate of 40 pellets per second and accelerates them to a speed of 1 km/s. Pellets are formed by extruding a billet of solidified deuterium through a 1.3-mm-diam nozzle at a speed of 5 cm/s. The extruding deuterium is chopped with a razor knife, forming 1.3-mm right circular cylinders of solid deuterium. The pellets are accelerated by synchronously injecting them into a high speed rotating arbor containing a guide track, which carries them from a point near the center of rotation to the periphery. The pellets leave the wheel after 150 0 of rotation at double the tip speed. The centrifuge is formed in the shape of a centrifugal catenary and is constructed of high strength KEVLAR/epoxy composite. This arbon has been spin-tested to a tip speed of 1 km/s

  16. Solid deuterium centrifuge pellet injector

    International Nuclear Information System (INIS)

    Foster, C.A.

    1983-01-01

    Pellet injectors are needed to fuel long pulse tokamak plasmas and other magnetic confinement devices. For this purpose, an apparatus has been developed that forms 1.3-mm-diam pellets of frozen deuterium at a rate of 40 pellets per second and accelerates them to a speed of 1 km/s. Pellets are formed by extruding a billet of solidified deuterium through a 1.3-mm-diam nozzle at a speed of 5 cm/s. The extruding deuterium is chopped with a razor knife, forming 1.3-mm right circular cylinders of solid deuterium. The pellets are accelerated by synchronously injecting them into a high speed rotating arbor containing a guide track, which carries them from a point near the center of rotation to the periphery. The pellets leave the wheel after 150 0 of rotation at double the tip speed. The centrifuge is formed in the shape of a centrifugal catenary and is constructed of high strength Kevlar/epoxy composite. This arbor has been spin-tested to a tip speed of 1 km/s

  17. Development and industrial application of gas centrifuges to uranium enrichment in the USSR

    International Nuclear Information System (INIS)

    Abbakumov, E.I.; Bazhenov, V.A.; Verbin, Yu.V.

    1989-01-01

    Review of state and studies in the field of gaseous diffusion technology and centrifugal method of uranium enrichment in the USSR is given. Domestic industrial gas centrifuges, forming to-day the main part of separation capacities in the USSR, are noted for low specific energy consumption and high reliability. Centrifugal technology in the USSR is applied both to uranium enrichment (including one for export) and to separation of isotopes of other chemical elements

  18. High stability design for new centrifugal compressor

    Science.gov (United States)

    Kanki, H.; Katayama, K.; Morii, S.; Mouri, Y.; Umemura, S.; Ozawa, U.; Oda, T.

    1989-01-01

    It is essential that high-performance centrifugal compressors be free of subsynchronous vibrations. A new high-performance centrifugal compressor has been developed by applying the latest rotordynamics knowledge and design techniques: (1) To improve the system damping, a specially designed oil film seal was developed. This seal attained a damping ratio three times that of the conventional design. The oil film seal contains a special damper ring in the seal cartridge. (2) To reduce the destabilizing effect of the labyrinth seal, a special swirl canceler (anti-swirl nozzle) was applied to the balance piston seal. (3) To confirm the system damping margin, the dynamic simulation rotor model test and the full load test applied the vibration exciting test in actual load conditions.

  19. Meridional Considerations of the Centrifugal Compressor Development

    Directory of Open Access Journals (Sweden)

    C. Xu

    2012-01-01

    Full Text Available Centrifugal compressor developments are interested in using optimization procedures that enable compressor high efficiency and wide operating ranges. Recently, high pressure ratio and efficiency of the centrifugal compressors require impeller design to pay attention to both the blade angle distribution and the meridional profile. The geometry of the blades and the meridional profile are very important contributions of compressor performance and structure reliability. This paper presents some recent studies of meridional impacts of the compressor. Studies indicated that the meridional profiles of the impeller impact the overall compressor efficiency and pressure ratio at the same rotational speed. Proper meridional profiles can improve the compressor efficiency and increase the overall pressure ratio at the same blade back curvature.

  20. Innovative taught MSc in Medical Visualisation and Human Anatomy.

    Science.gov (United States)

    Clunie, Lauren; Livingstone, Daniel; Rea, Paul M

    2015-06-01

    A relatively new, fully accredited MSc in Medical Visualisation and Human Anatomy, is now offered through a joint collaboration with the Laboratory of Human Anatomy, University of Glasgow and the Digital Design Studio, Glasgow School of Art. This degree combines training in digital technologies and intensive human anatomy training as a result of a long-standing successful partnership between these two esteemed institutes. The student also has to complete a research dissertation which encompasses both the digital perspective and a related medical, dental, surgical, veterinary (comparative anatomy) or life science specialty to enhance development in the digital field for a variety of specialties. This article discusses the background in development of this degree, the course structure and the career prospects and destinations for graduates of this unique degree programme.