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Sample records for beta propeller wdr72

  1. Mutations in the Beta Propeller WDR72 Cause Autosomal-Recessive Hypomaturation Amelogenesis Imperfecta

    Science.gov (United States)

    El-Sayed, Walid; Parry, David A.; Shore, Roger C.; Ahmed, Mushtaq; Jafri, Hussain; Rashid, Yasmin; Al-Bahlani, Suhaila; Al Harasi, Sharifa; Kirkham, Jennifer; Inglehearn, Chris F.; Mighell, Alan J.

    2009-01-01

    Healthy dental enamel is the hardest and most highly mineralized human tissue. Though acellular, nonvital, and without capacity for turnover or repair, it can nevertheless last a lifetime. Amelogenesis imperfecta (AI) is a collective term for failure of normal enamel development, covering diverse clinical phenotypes that typically show Mendelian inheritance patterns. One subset, known as hypomaturation AI, is characterised by near-normal volumes of organic enamel matrix but with weak, creamy-brown opaque enamel that fails prematurely after tooth eruption. Mutations in genes critical to enamel matrix formation have been documented, but current understanding of other key events in enamel biomineralization is limited. We investigated autosomal-recessive hypomaturation AI in a consanguineous Pakistani family. A whole-genome SNP autozygosity screen identified a locus on chromosome 15q21.3. Sequencing candidate genes revealed a point mutation in the poorly characterized WDR72 gene. Screening of WDR72 in a panel of nine additional hypomaturation AI families revealed the same mutation in a second, apparently unrelated, Pakistani family and two further nonsense mutations in Omani families. Immunohistochemistry confirmed intracellular localization in maturation-stage ameloblasts. WDR72 function is unknown, but as a putative β propeller is expected to be a scaffold for protein-protein interactions. The nearest homolog, WDR7, is involved in vesicle mobilization and Ca2+-dependent exocytosis at synapses. Vesicle trafficking is important in maturation-stage ameloblasts with respect to secretion into immature enamel and removal of cleaved enamel matrix proteins via endocytosis. This raises the intriguing possibility that WDR72 is critical to ameloblast vesicle turnover during enamel maturation. PMID:19853237

  2. Identification of the first multi-exonic WDR72 deletion in isolated amelogenesis imperfecta, and generation of a WDR72-specific copy number screening tool.

    Science.gov (United States)

    Hentschel, Julia; Tatun, Dana; Parkhomchuk, Dmitri; Kurth, Ingo; Schimmel, Bettina; Heinrich-Weltzien, Roswitha; Bertzbach, Sabine; Peters, Hartmut; Beetz, Christian

    2016-09-15

    Amelogenesis imperfecta (AI) is a clinically and genetically heterogeneous disorder of tooth development which is due to aberrant deposition or composition of enamel. Both syndromic and isolated forms exist; they may be inherited in an X-linked, autosomal recessive, or autosomal dominant manner. WDR72 is one of ten currently known genes for recessive isolated AI; nine WDR72 mutations affecting single nucleotides have been described to date. Based on whole exome sequencing in a large consanguineous AI pedigree, we obtained evidence for presence of a multi-exonic WDR72 deletion. A home-made multiplex ligation-dependent probe amplification assay was used to confirm the aberration, to narrow its extent, and to identify heterozygous carriers. Our study extends the mutational spectrum for WDR72 to include large deletions, and supports a relevance of the previously proposed loss-of-function mechanism. It also introduces an easy-to-use and highly sensitive tool for detecting WDR72 copy number alterations. PMID:27259663

  3. Evolution of the beta-propeller fold.

    OpenAIRE

    Chaudhuri, I.; Söding, J.; Lupas, A.

    2008-01-01

    β-Propellers are toroidal folds, in which repeated, four-stranded β-meanders are arranged in a circular and slightly tilted fashion, like the blades of a propeller. They are found in all domains of life, with a strong preponderance among eukaryotes. Propellers show considerable sequence diversity and are classified into six separate structural groups by the SCOP and CATH databases. Despite this diversity, they often show similarities across groups, not only in structure but also in sequence, ...

  4. Prediction of a common beta-propeller catalytic domain for fructosyltransferases of different origin and substrate specificity.

    OpenAIRE

    Pons, T.; L. Hernández; Batista, F. R.; Chinea, G.

    2000-01-01

    The three-dimensional (3D) structure of fructan biosynthetic enzymes is still unknown. Here, we have explored folding similarities between reported microbial and plant enzymes that catalyze transfructosylation reactions. A sequence-structure compatibility search using TOPITS, SDP, 3D-PSSM, and SAM-T98 programs identified a beta-propeller fold with scores above the confidence threshold that indicate a structurally conserved catalytic domain in fructosyltransferases (FTFs) of diverse origin and...

  5. Structural Characterization of the Boca/Mesd Maturation Factors for LDL-Receptor-Type beta Propeller Domains

    Energy Technology Data Exchange (ETDEWEB)

    M Collins; W Hendrickson

    2011-12-31

    Folding and trafficking of low-density lipoprotein receptor (LDLR) family members, which play essential roles in development and homeostasis, are mediated by specific chaperones. The Boca/Mesd chaperone family specifically promotes folding and trafficking of the YWTD {beta} propeller-EGF domain pair found in the ectodomain of all LDLR members. Limited proteolysis, NMR spectroscopy, analytical ultracentrifugation, and X-ray crystallography were used to define a conserved core composed of a structured domain that is preceded by a disordered N-terminal region. High-resolution structures of the ordered domain were determined for homologous proteins from three metazoans. Seven independent protomers reveal a novel ferrodoxin-like superfamily fold with two distinct {beta} sheet topologies. A conserved hydrophobic surface forms a dimer interface in each crystal, but these differ substantially at the atomic level, indicative of nonspecific hydrophobic interactions that may play a role in the chaperone activity of the Boca/Mesd family.

  6. Conservation of the Human Integrin-Type Beta-Propeller Domain in Bacteria

    Science.gov (United States)

    Chouhan, Bhanupratap; Denesyuk, Alexander; Heino, Jyrki; Johnson, Mark S.; Denessiouk, Konstantin

    2011-01-01

    Integrins are heterodimeric cell-surface receptors with key functions in cell-cell and cell-matrix adhesion. Integrin α and β subunits are present throughout the metazoans, but it is unclear whether the subunits predate the origin of multicellular organisms. Several component domains have been detected in bacteria, one of which, a specific 7-bladed β-propeller domain, is a unique feature of the integrin α subunits. Here, we describe a structure-derived motif, which incorporates key features of each blade from the X-ray structures of human αIIbβ3 and αVβ3, includes elements of the FG-GAP/Cage and Ca2+-binding motifs, and is specific only for the metazoan integrin domains. Separately, we searched for the metazoan integrin type β-propeller domains among all available sequences from bacteria and unicellular eukaryotic organisms, which must incorporate seven repeats, corresponding to the seven blades of the β-propeller domain, and so that the newly found structure-derived motif would exist in every repeat. As the result, among 47 available genomes of unicellular eukaryotes we could not find a single instance of seven repeats with the motif. Several sequences contained three repeats, a predicted transmembrane segment, and a short cytoplasmic motif associated with some integrins, but otherwise differ from the metazoan integrin α subunits. Among the available bacterial sequences, we found five examples containing seven sequential metazoan integrin-specific motifs within the seven repeats. The motifs differ in having one Ca2+-binding site per repeat, whereas metazoan integrins have three or four sites. The bacterial sequences are more conserved in terms of motif conservation and loop length, suggesting that the structure is more regular and compact than those example structures from human integrins. Although the bacterial examples are not full-length integrins, the full-length metazoan-type 7-bladed β-propeller domains are present, and sometimes two tandem

  7. Conservation of the human integrin-type beta-propeller domain in bacteria.

    Directory of Open Access Journals (Sweden)

    Bhanupratap Chouhan

    Full Text Available Integrins are heterodimeric cell-surface receptors with key functions in cell-cell and cell-matrix adhesion. Integrin α and β subunits are present throughout the metazoans, but it is unclear whether the subunits predate the origin of multicellular organisms. Several component domains have been detected in bacteria, one of which, a specific 7-bladed β-propeller domain, is a unique feature of the integrin α subunits. Here, we describe a structure-derived motif, which incorporates key features of each blade from the X-ray structures of human αIIbβ3 and αVβ3, includes elements of the FG-GAP/Cage and Ca(2+-binding motifs, and is specific only for the metazoan integrin domains. Separately, we searched for the metazoan integrin type β-propeller domains among all available sequences from bacteria and unicellular eukaryotic organisms, which must incorporate seven repeats, corresponding to the seven blades of the β-propeller domain, and so that the newly found structure-derived motif would exist in every repeat. As the result, among 47 available genomes of unicellular eukaryotes we could not find a single instance of seven repeats with the motif. Several sequences contained three repeats, a predicted transmembrane segment, and a short cytoplasmic motif associated with some integrins, but otherwise differ from the metazoan integrin α subunits. Among the available bacterial sequences, we found five examples containing seven sequential metazoan integrin-specific motifs within the seven repeats. The motifs differ in having one Ca(2+-binding site per repeat, whereas metazoan integrins have three or four sites. The bacterial sequences are more conserved in terms of motif conservation and loop length, suggesting that the structure is more regular and compact than those example structures from human integrins. Although the bacterial examples are not full-length integrins, the full-length metazoan-type 7-bladed β-propeller domains are present, and

  8. Tandem repeat of a seven-bladed beta-propeller domain in oligoxyloglucan reducing-end-specific cellobiohydrolase.

    Science.gov (United States)

    Yaoi, Katsuro; Kondo, Hidemasa; Noro, Natsuko; Suzuki, Mamoru; Tsuda, Sakae; Mitsuishi, Yasushi

    2004-07-01

    Oligoxyloglucan reducing-end-specific cellobiohydrolase (OXG-RCBH; EC 3.2.1.150) is an exoglucanase that recognizes the reducing end of oligoxyloglucan and releases two glucosyl residue segments from the main chain. The X-ray crystal structure of OXG-RCBH determined at 2.2 A resolution reveals a unique feature of this enzyme; OXG-RCBH consists of a tandem repeat of two similar domains, which are both folded into seven-bladed beta-propeller structures. The sequence alignment of the propeller blades, based on the structure, indicates that a weak repeat of the amino acid sequence occurred seven times to construct each domain. There is a cleft that can accommodate the substrate oligosaccharide between the two domains, which is a putative substrate binding subsite. Mutation of either Asp35 or Asp465, located in the putative catalytic center, to Asn resulted in a protein with no detectable catalytic activity, indicating the critical role of these amino acids in catalysis. PMID:15242597

  9. C-terminus of progranulin interacts with the beta-propeller region of sortilin to regulate progranulin trafficking.

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    Yanqiu Zheng

    Full Text Available Progranulin haplo-insufficiency is a main cause of frontotemporal lobar degeneration (FTLD with TDP-43 aggregates. Previous studies have shown that sortilin regulates progranulin trafficking and is a main determinant of progranulin level in the brain. In this study, we mapped the binding site between progranulin and sortilin. Progranulin binds to the beta-propeller region of sortilin through its C-terminal tail. The C-terminal progranulin fragment is fully sufficient for sortilin binding and progranulin C-terminal peptide displaces progranulin binding to sortilin. Deletion of the last 3 residues of progranulin (QLL abolishes its binding to sortilin and also sortilin dependent regulation of progranulin trafficking. Since progranulin haplo-insufficiency results in FTLD, these results may provide important insights into future studies of progranulin trafficking and signaling and progranulin based therapy for FTLD.

  10. Beta-propeller protein-associated neurodegeneration: a new X-linked dominant disorder with brain iron accumulation

    Science.gov (United States)

    Hayflick, Susan J.; Kruer, Michael C.; Gregory, Allison; Haack, Tobias B.; Kurian, Manju A.; Houlden, Henry H.; Anderson, James; Boddaert, Nathalie; Sanford, Lynn; Harik, Sami I.; Dandu, Vasuki H.; Nardocci, Nardo; Zorzi, Giovanna; Dunaway, Todd; Tarnopolsky, Mark; Skinner, Steven; Holden, Kenton R.; Frucht, Steven; Hanspal, Era; Schrander-Stumpel, Connie; Mignot, Cyril; Héron, Delphine; Saunders, Dawn E.; Kaminska, Margaret; Lin, Jean-Pierre; Lascelles, Karine; Cuno, Stephan M.; Meyer, Esther; Garavaglia, Barbara; Bhatia, Kailash; de Silva, Rajith; Crisp, Sarah; Lunt, Peter; Carey, Martyn; Hardy, John; Meitinger, Thomas; Prokisch, Holger; Hogarth, Penelope

    2013-01-01

    Neurodegenerative disorders with high iron in the basal ganglia encompass an expanding collection of single gene disorders collectively known as neurodegeneration with brain iron accumulation. These disorders can largely be distinguished from one another by their associated clinical and neuroimaging features. The aim of this study was to define the phenotype that is associated with mutations in WDR45, a new causative gene for neurodegeneration with brain iron accumulation located on the X chromosome. The study subjects consisted of WDR45 mutation-positive individuals identified after screening a large international cohort of patients with idiopathic neurodegeneration with brain iron accumulation. Their records were reviewed, including longitudinal clinical, laboratory and imaging data. Twenty-three mutation-positive subjects were identified (20 females). The natural history of their disease was remarkably uniform: global developmental delay in childhood and further regression in early adulthood with progressive dystonia, parkinsonism and dementia. Common early comorbidities included seizures, spasticity and disordered sleep. The symptoms of parkinsonism improved with l-DOPA; however, nearly all patients experienced early motor fluctuations that quickly progressed to disabling dyskinesias, warranting discontinuation of l-DOPA. Brain magnetic resonance imaging showed iron in the substantia nigra and globus pallidus, with a ‘halo’ of T1 hyperintense signal in the substantia nigra. All patients harboured de novo mutations in WDR45, encoding a beta-propeller protein postulated to play a role in autophagy. Beta-propeller protein-associated neurodegeneration, the only X-linked disorder of neurodegeneration with brain iron accumulation, is associated with de novo mutations in WDR45 and is recognizable by a unique combination of clinical, natural history and neuroimaging features. PMID:23687123

  11. A novel human tectonin protein with multivalent beta-propeller folds interacts with ficolin and binds bacterial LPS.

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    Diana Hooi Ping Low

    Full Text Available BACKGROUND: Although the human genome database has been completed a decade ago, approximately 50% of the proteome remains hypothetical as their functions are unknown. The elucidation of the functions of these hypothetical proteins can lead to additional protein pathways and revelation of new cascades. However, many of these inferences are limited to proteins with substantial sequence similarity. Of particular interest here is the Tectonin domain-containing family of proteins. METHODOLOGY/PRINCIPAL FINDINGS: We have identified hTectonin, a hypothetical protein in the human genome database, as a distant ortholog of the limulus galactose binding protein (GBP. Phylogenetic analysis revealed strong evolutionary conservation of hTectonin homologues from parasite to human. By computational analysis, we showed that both the hTectonin and GBP form beta-propeller structures with multiple Tectonin domains, each containing beta-sheets of 4 strands per beta-sheet. hTectonin is present in the human leukocyte cDNA library and immune-related cell lines. It interacts with M-ficolin, a known human complement protein whose ancient homolog, carcinolectin (CL5, is the functional protein partner of GBP during infection. Yeast 2-hybrid assay showed that only the Tectonin domains of hTectonin recognize the fibrinogen-like domain of the M-ficolin. Surface plasmon resonance analysis showed real-time interaction between the Tectonin domains 6 & 11 and bacterial LPS, indicating that despite forming 2 beta-propellers with its different Tectonin domains, the hTectonin molecule could precisely employ domains 6 & 11 to recognise bacteria. CONCLUSIONS/SIGNIFICANCE: By virtue of a recent finding of another Tectonin protein, leukolectin, in the human leukocyte, and our structure-function analysis of the hypothetical hTectonin, we propose that Tectonin domains of proteins could play a vital role in innate immune defense, and that this function has been conserved over several

  12. The beta-propeller protein YxaL increases the processivity of the PcrA helicase.

    Science.gov (United States)

    Noirot-Gros, M-F; Soultanas, P; Wigley, D B; Ehrlich, S D; Noirot, P; Petit, M-A

    2002-05-01

    The DNA helicase PcrA is found in gram-positive bacteria and belongs to the superfamily 1 (SF1) of helicases, together with Rep and UvrD helicases from Escherichia coli. These helicases have been extensively studied in vitro and their mode of unwinding are well characterised. However, little is known about the putative cellular partners of such helicases. To identify PcrA-interacting factors, PcrA was used as a bait in a genome-wide yeast two-hybrid screen of a Bacillus subtilis library. Three proteins with unknown functions - YxaL, YwhK and YerB - were found to interact specifically with PcrA. The yxaL gene was cloned, the product was overexpressed and purified, and its effect on the PcrA activity was investigated in vitro. YxaL enhanced the processivity of the PcrA helicase. A comparison of the amino acid sequence of YxaL with other proteins from data banks suggests that YxaL belongs to a family of proteins with a repeated domain, which adopt a typical three-dimensional structure designated as a "beta-propeller". This raises the possibility that YxaL acts as a connector protein between PcrA and another cellular component. PMID:12073041

  13. Optimization of five environmental factors to increase beta-propeller phytase production in Pichia pastoris and impact on the physiological response of the host.

    Science.gov (United States)

    Viader-Salvadó, José M; Castillo-Galván, Miguel; Fuentes-Garibay, José A; Iracheta-Cárdenas, María M; Guerrero-Olazarán, Martha

    2013-01-01

    Recently, we engineered Pichia pastoris Mut(s) strains to produce several beta-propeller phytases, one from Bacillus subtilis and the others designed by a structure-guided consensus approach. Furthermore, we demonstrated the ability of P. pastoris to produce and secrete these phytases in an active form in shake-flask cultures. In the present work, we used a design of experiments strategy (Simplex optimization method) to optimize five environmental factors that define the culture conditions in the induction step to increase beta-propeller phytase production in P. pastoris bioreactor cultures. With the optimization process, up to 347,682 U (82,814 U/L or 6.4 g/L culture medium) of phytase at 68 h of induction was achieved. In addition, the impact of the optimization process on the physiological response of the host was evaluated. The results indicate that the increase in extracellular phytase production through the optimization process was correlated with an increase in metabolic activity of P. pastoris, shown by an increase in oxygen demand and methanol consumption, that increase the specific growth rate. The increase in extracellular phytase production also occurred with a decrease in extracellular protease activity. Moreover, the optimized culture conditions increased the recombinant protein secretion by up to 88%, along with the extracellular phytase production efficiency per cell. PMID:24123973

  14. Low pH-Triggered Beta-Propeller Switch of the Low-Density Lipoprotein Receptor Assists Rhinovirus Infection ▿

    Science.gov (United States)

    Konecsni, Tuende; Berka, Ursula; Pickl-Herk, Angela; Bilek, Gerhard; Khan, Abdul Ghafoor; Gajdzig, Leszek; Fuchs, Renate; Blaas, Dieter

    2009-01-01

    Minor group human rhinoviruses (HRVs) bind three members of the low-density lipoprotein receptor (LDLR) family: LDLR proper, very-LDLR (VLDLR) and LDLR-related protein (LRP). Whereas ICAM-1, the receptor of major group HRVs actively contributes to viral uncoating, LDLRs are rather considered passive vehicles for cargo delivery to the low-pH environment of endosomes. Since the Tyr-Trp-Thr-Asp β-propeller domain of LDLR has been shown to be involved in the dissociation of bound LDL via intramolecular competition at low pH, we studied whether it also plays a role in HRV infection. Human cell lines deficient in LDLR family proteins are not available. Therefore, we used CHO-ldla7 cells that lack endogenous LDLR. These were stably transfected to express either wild-type (wt) human LDLR or a mutant with a deletion of the β-propeller. When HRV2 was attached to the propeller-negative LDLR, a lower pH was required for conversion to subviral particles than when attached to wt LDLR. This indicates that high-avidity receptor binding maintains the virus in its native conformation. HRV2 internalization directed the mutant LDLR but not wt LDLR to lysosomes, resulting in reduced plasma membrane expression of propeller-negative LDLR. Infection assays using a CHO-adapted HRV2 variant showed a delay in intracellular viral conversion and de novo viral synthesis in cells expressing the truncated LDLR. Our data indicate that the β-propeller attenuates the virus-stabilizing effect of LDLR binding and thereby facilitates RNA release from endosomes, resulting in the enhancement of infection. This is a nice example of a virus exploiting high-avidity multimodule receptor binding with an intrinsic release mechanism. PMID:19706701

  15. Design of Thermostable Beta-Propeller Phytases with Activity over a Broad Range of pHs and Their Overproduction by Pichia pastoris▿

    Science.gov (United States)

    Viader-Salvadó, José M.; Gallegos-López, Juan A.; Carreón-Treviño, J. Gerardo; Castillo-Galván, Miguel; Rojo-Domínguez, Arturo; Guerrero-Olazarán, Martha

    2010-01-01

    Thermostable phytases, which are active over broad pH ranges, may be useful as feed additives, since they can resist the temperatures used in the feed-pelleting process. We designed new beta-propeller phytases, using a structure-guided consensus approach, from a set of amino acid sequences from Bacillus phytases and engineered Pichia pastoris strains to overproduce the enzymes. The recombinant phytases were N-glycosylated, had the correct amino-terminal sequence, showed activity over a pH range of 2.5 to 9, showed a high residual activity after 10 min of heat treatment at 80°C and pH 5.5 or 7.5, and were more thermostable at pH 7.5 than a recombinant form of phytase C from Bacillus subtilis (GenBank accession no. AAC31775). A structural analysis suggested that the higher thermostability may be due to a larger number of hydrogen bonds and to the presence of P257 in a surface loop. In addition, D336 likely plays an important role in the thermostability of the phytases at pH 7.5. The recombinant phytases showed higher thermostability at pH 5.5 than at pH 7.5. This difference was likely due to a different protein total charge at pH 5.5 from that at pH 7.5. The recombinant beta-propeller phytases described here may have potential as feed additives and in the pretreatment of vegetable flours used as ingredients in animal diets. PMID:20693453

  16. DR1769, a Protein with N-Terminal Beta Propeller Repeats and a Low-Complexity Hydrophilic Tail, Plays a Role in Desiccation Tolerance of Deinococcus radiodurans

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    Rajpurohit, Yogendra S.

    2013-01-01

    The Deinococcus radiodurans genome encodes five putative quinoproteins. Among these, the Δdr2518 and Δdr1769 mutants became sensitive to gamma radiation. DR2518 with beta propeller repeats in the C-terminal domain was characterized as a radiation-responsive serine/threonine protein kinase in this bacterium. DR1769 contains beta propeller repeats at the N terminus, while its C-terminal domain is a proline-rich disordered structure and constitutes a low-complexity hydrophilic region with aliphatic-proline dipeptide motifs. The Δdr1769 mutant showed nearly a 3-log cycle sensitivity to desiccation at 5% humidity compared to that of the wild type. Interestingly, the gamma radiation and mitomycin C (MMC) resistance in mutant cells also dropped by ∼1-log cycle at 10 kGy and ∼1.5-fold, respectively, compared to those in wild-type cells. But there was no effect of UV (254 nm) exposure up to 800 J · m−2. These cells showed defective DNA double-strand break repair, and the average size of the nucleoid in desiccated wild-type and Δdr1769 cells was reduced by approximately 2-fold compared to that of respective controls. However, the nucleoid in wild-type cells returned to a size almost similar to that of the untreated control, which did not happen in mutant cells, at least up to 24 h postdesiccation. These results suggest that DR1769 plays an important role in desiccation and radiation resistance of D. radiodurans, possibly by protecting genome integrity under extreme conditions. PMID:23794625

  17. Mobius propeller

    Directory of Open Access Journals (Sweden)

    Leonid I. Gretchihin

    2014-04-01

    Full Text Available The article gives a detailed molecular-kinetic theory of the Mobius propeller functioning and shows the implementation of its computer modelling in different exploitation conditions. The mechanisation of the Mobius propeller can be carried out in such a way that, under certain conditions, it enables using this type of propellers as a heat pump. The developed theory of the Mobius propeller functioning has been experimentally verified in laboratory conditions.

  18. Mobius propeller

    OpenAIRE

    Leonid I. Gretchihin; А. L. Gushtchin; А. А. Narushevitch

    2014-01-01

    The article gives a detailed molecular-kinetic theory of the Mobius propeller functioning and shows the implementation of its computer modelling in different exploitation conditions. The mechanisation of the Mobius propeller can be carried out in such a way that, under certain conditions, it enables using this type of propellers as a heat pump. The developed theory of the Mobius propeller functioning has been experimentally verified in laboratory conditions.

  19. [A woman with beta-propeller protein-associated neurodegeneration identified by the WDR45 mutation presenting as Rett-like syndrome in childhood].

    Science.gov (United States)

    Morisada, Naoya; Tsuneishi, Syuichi; Taguchi, Kazuhiro; Yagi, Ryuzaburo; Nishiyama, Masahiro; Toyoshima, Daisaku; Nakagawa, Taku; Takeshima, Yasuhiro; Takada, Satoshi; Iijima, Kazumoto

    2016-05-01

    Beta-propeller protein-associated neurodegeneration (BPAN) is one of the neurodegenerative disorders characterized by iron deposition in the brain and is the only known disease in humans to be caused by an aberration in autophagocytosis. Here, we present the case of a 42-year-old woman with BPAN identified by the WDR45 mutation. From early childhood, she was recognized as having global developmental delay, and she frequently sucked her hand, which was considered to be a stereotypical movement. She had a febrile convulsion at 6 months of age but there was no history of epilepsy. The delay in language development was more severe than the delay in motor development; she was able to dress herself, walk unaided, and follow simple instructions until adolescence. After the age of 20, her movement ability rapidly declined. By the time she was 42 years old, she was bedridden and unable to communicate. Brain magnetic resonance imaging (MRI) at 21 years revealed no abnormality except non-specific cerebral atrophy. However, MRI at 39 years revealed abnormalities in the globus pallidus and substantia nigra, with neurodegeneration and iron accumulation in the brain. Genetic analysis for WDR45 revealed that she had a splice site mutation (NM_007075.3: c.830 + 2 T > C) which was previously reported, and a diagnosis of BPAN was confirmed. For specific therapies to be developed for BPAN in the future, it is necessary to establish early diagnosis, including genetic analysis. PMID:27349085

  20. INTERCEPTOR PROPELLER

    OpenAIRE

    Mancini, Andrea

    2010-01-01

    The Interceptor Propeller is a useful device thanks to which it is possible to quickly change propeller pitch both simply and at an affordable price to fixed bladed propellers. This becomes a must when fine tuning a new boat but also when upgrading engines on a given boat or when the characteristics of the existing boat in terms of displacement are modified.

  1. Sequence and structural analysis of the Asp-box motif and Asp-box beta-propellers; a widespread propeller-type characteristic of the Vps10 domain family and several glycoside hydrolase families

    Directory of Open Access Journals (Sweden)

    Quistgaard Esben M

    2009-07-01

    Full Text Available Abstract Background The Asp-box is a short sequence and structure motif that folds as a well-defined β-hairpin. It is present in different folds, but occurs most prominently as repeats in β-propellers. Asp-box β-propellers are known to be characteristically irregular and to occur in many medically important proteins, most of which are glycosidase enzymes, but they are otherwise not well characterized and are only rarely treated as a distinct β-propeller family. We have analyzed the sequence, structure, function and occurrence of the Asp-box and s-Asp-box -a related shorter variant, and provide a comprehensive classification and computational analysis of the Asp-box β-propeller family. Results We find that all conserved residues of the Asp-box support its structure, whereas the residues in variable positions are generally used for other purposes. The Asp-box clearly has a structural role in β-propellers and is highly unlikely to be involved in ligand binding. Sequence analysis of the Asp-box β-propeller family reveals it to be very widespread especially in bacteria and suggests a wide functional range. Disregarding the Asp-boxes, sequence conservation of the propeller blades is very low, but a distinct pattern of residues with specific properties have been identified. Interestingly, Asp-boxes are occasionally found very close to other propeller-associated repeats in extensive mixed-motif stretches, which strongly suggests the existence of a novel class of hybrid β-propellers. Structural analysis reveals that the top and bottom faces of Asp-box β-propellers have striking and consistently different loop properties; the bottom is structurally conserved whereas the top shows great structural variation. Interestingly, only the top face is used for functional purposes in known structures. A structural analysis of the 10-bladed β-propeller fold, which has so far only been observed in the Asp-box family, reveals that the inner strands of the

  2. High efficiency propeller; Kokoritsu propeller

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, S

    1998-09-01

    Propellers of ships are many and diverse starting from small 18cm propeller of speed boat to large propeller more than 10m long used for Very Large Crude Oil Carrier. Accordingly, requirements for characteristics differ according to type of ship. The common characteristics considered for these propellers are (1) independent performance of propeller (efficiency) (2) vibromotive force of propeller (vibration/noise) (3) cavitation (4) blade stress. Efficiency of propeller is directly related to the need of save energy, high speed and so forth and it is the most important property. Vibromotive force of propeller is directly related with the positioning and damage of vessel parts. On the other hand, cavitation is the greatest factor for surface force generation and cavitation erosion leads to the reduction of efficiency. Further, higher blade stress leads to blade damage. In this report, design system and design of highly efficient propeller for different ships, and outline of highly efficient PAI propeller are introduced. 7 refs., 2 tabs.

  3. Green Propellants

    OpenAIRE

    Rahm, Martin

    2010-01-01

    To enable future environmentally friendly access to space by means of solid rocket propulsion a viable replacement to the hazardous ammonium perchlorate oxidizer is needed. Ammonium dinitramide (ADN) is one of few such compounds currently known. Unfortunately compatibility issues with many polymer binder systems and unexplained solid-state behavior have thus far hampered the development of ADN-based propellants. Chapters one, two and three offer a general introduction to the thesis, and into ...

  4. Elevation of neuron specific enolase and brain iron deposition on susceptibility-weighted imaging as diagnostic clues for beta-propeller protein-associated neurodegeneration in early childhood: Additional case report and review of the literature.

    Science.gov (United States)

    Takano, Kyoko; Shiba, Naoko; Wakui, Keiko; Yamaguchi, Tomomi; Aida, Noriko; Inaba, Yuji; Fukushima, Yoshimitsu; Kosho, Tomoki

    2016-02-01

    Beta-propeller protein-associated neurodegeneration (BPAN), also known as static encephalopathy of childhood with neurodegeneration in adulthood (SENDA), is a subtype of neurodegeneration with brain iron accumulation (NBIA). BPAN is caused by mutations in an X-linked gene WDR45 that is involved in autophagy. BPAN is characterized by developmental delay or intellectual disability until adolescence or early adulthood, followed by severe dystonia, parkinsonism, and progressive dementia. Brain magnetic resonance imaging (MRI) shows iron deposition in the bilateral globus pallidus (GP) and substantia nigra (SN). Clinical manifestations and laboratory findings in early childhood are limited. We report a 3-year-old girl with BPAN who presented with severe developmental delay and characteristic facial features. In addition to chronic elevation of serum aspartate transaminase, lactate dehydrogenase, creatine kinase, and soluble interleukin-2 receptor, she had persistent elevation of neuron specific enolase (NSE) in serum and cerebrospinal fluid. MRI using susceptibility-weighted imaging (SWI) demonstrated iron accumulation in the GP and SN bilaterally. Targeted next-generation sequencing identified a de novo splice-site mutation, c.831-1G>C in WDR45, which resulted in aberrant splicing evidenced by reverse transcriptase-PCR. Persistent elevation of NSE and iron deposition on SWI may provide clues for diagnosis of BPAN in early childhood. PMID:26481852

  5. Perancangan Propeler Self-Propelled Barge

    Directory of Open Access Journals (Sweden)

    Billy Teguh kurniawan

    2013-03-01

    Full Text Available Makalah ini menyampaikan suatu penelitian tentang perancangan propeler yang optimal beserta pemilihan daya mesin yang efisien pada self-propelled barge dengan memperhitungkan besarnya nilai tahanan dari barge tersebut. Dengan penambahan sistem propulsi, diharapkan barge dapat beroperasi dengan lebih efisien dibandingkan saat barge beroperasi menggunakan sistem towing atau ditarik tug boat. Perhitungan tahanan barge dilakukan menggunakan metode Holtrop dan Guldhammer-Harvald sehingga dapat diperhi-tungkan geometri dan jenis propeler yang optimal beserta daya mesin yang efisien untuk barge. Propeler yang dianalisis adalah propeler tipe B-Troost Series, sedangkan variasi yang dilakukan untuk perencanaan propeler pada kajian ini adalah variasi putaran propeler pada rentang antara 310-800 rpm, serta variasi jumlah daun pada rentang tiga, empat, lima, dan enam. Besarnya nilai tahanan self-propelled barge untuk metode Holtrop adalah 105.91 kilonewton, sedangkan hasil per-hitungan dari metode Guldhammer-Harvald didapatkan nilai sebesar 109.14 kilonewton. Tipe propeler yang dipilih setelah dilakukan uji kavitasi adalah tipe Troost Series B4-40, dengan diameter sebesar 2.1 m, efisiensi sebesar 0.421, pitch ratio se-besar 0.591, dengan putaran propeler 400 rpm. Daya mesin yg dibutuhkan barge pada kondisi maksimum (BHPMCR sebesar 1669.5 HP. Dengan mempertimbangkan daya tersebut, maka dipilih mesin jenis Caterpillar tipe Marine 3516B yang mem-punyai daya maksimum sebesar 1285 kilowatt atau 1722.5 horsepower dengan putaran mesin sebesar 1200 rpm

  6. Tip-modified Propellers

    DEFF Research Database (Denmark)

    Andersen, Poul

    1999-01-01

    The paper deals with tip-modified propellers and the methods which, over a period of two decades, have been applied to develop such propellers. The development is driven by the urge to increase the efficiency of propellers and can be seen as analogous to fitting end plates and winglets to aircraft...... wings. The literature on four different designs is reviewed: the end-plate propeller; the two-sided, shifted end-plate propeller; the tip-fin propeller; and the bladelet propeller. The conclusion is that it is indeed possible to design tip-modified propellers that, relative to an optimum conventional...... propeller, have efficiency increases of a reasonable magnitude in both open-water and behind-ship conditions....

  7. Contra-rotating propeller; Niju hanten propeller

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Y. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)] Kushiyama, H. [Mitsubishi Heavy Industries Ltd., Tokyo (Japan)] Nitta, K. [Sumitomo Heavy Industries Ltd., Tokyo (Japan)

    1998-09-01

    Contra-rotating propeller (CR) is a save energy device where two propellers are set on one shaft and they are contra-rotated, later propeller recovers the unused energy caused by the rotation of first propeller and changes into effective propeller force. Development of optimum design method of CRP, compact helical gear device, contra-rotating shaft, contra-rotating seal and so forth are the technical topics for making practical use of CRP device for large cargo vessels. At present, there are four vessels on sail that use CRP and they are 37,000t cargo vessel and 258,000t oil tanker using CRP device of Ishikawajima-Harima Heavy Industries Co., Ltd., and vessel for carrying vehicles and 258,000t tanker using the CRP device of Mitsubishi Heavy Industries, Ltd. Main purpose of using CRP device in large cargo vessels is to save energy and reduction of maximum horse power of 15% was possible as compared with the one propeller vessel when compared with the same vessel speed. In this report, structure and characteristics of the CRP device for each company are explained and the practical findings of vessels on work are introduced. 10 figs.

  8. Stochastic flights of propellers

    OpenAIRE

    Pan, Margaret; Rein, Hanno; Chiang, Eugene; Evans, Steven N.

    2012-01-01

    Kilometer-sized moonlets in Saturn's A ring create S-shaped wakes called "propellers" in surrounding material. The Cassini spacecraft has tracked the motions of propellers for several years and finds that they deviate from Keplerian orbits having constant semimajor axes. The inferred orbital migration is known to switch sign. We show using a statistical test that the time series of orbital longitudes of the propeller Bl\\'eriot is consistent with that of a time-integrated Gaussian random walk....

  9. PARAMETER DESIGN PROPELLER KAPAL

    OpenAIRE

    Muhammad Ridwan; - Sulaiman

    2012-01-01

      Designer propeller kapal harus mempertimbangkan berbagai parameter untuk menghasilkan bentuk, type dan ukuran propeller yang memiliki nilai  efektifitas dan effisiensi propulsi tinggi. Propulsi kapal merupakan faktor yang mendominasi  operasional kapal, karena pemakaian bahan bakar untuk operasional propulsi kapal merupakan 42% dari total cost operasional kapal dan merupakan added value yang akan diperoleh oleh perusahaan pelayaran. Pertimbangan parameter desain propeller arg...

  10. Propeller design by optimization

    Science.gov (United States)

    Rizk, M. H.; Jou, W.-H.

    1986-01-01

    The feasibility of designing propellers by an optimization procedure is investigated. A scheme, which solves the full potential flow equation about a propeller by line relaxation, is modified so that the iterative solutions of the flow equation and the design parameters are updated simultaneously. Some technical problems in using optimization for designing propellers with maximum efficiency are identified. Approaches for overcoming these problems are presented.

  11. Hydrodynamics of Ship Propellers

    DEFF Research Database (Denmark)

    Breslin, John P.; Andersen, Poul

    This book deals with flows over propellers operating behind ships, and the hydrodynamic forces and moments which the propeller generates on the shaft and on the ship hull.The first part of the text is devoted to fundamentals of the flow about hydrofoil sections (with and without cavitation) and a...

  12. Propellant-remaining modeling

    Science.gov (United States)

    Torgovitsky, S.

    1991-01-01

    A successful satellite mission is predicted upon the proper maintenance of the spacecraft's orbit and attitude. One requirement for planning and predicting the orbit and attitude is the accurate estimation of the propellant remaining onboard the spacecraft. Focuss is on the three methods that were developed for calculating the propellant budget: the errors associated with each method and the uncertainties in the variables required to determine the propellant remaining that contribute to these errors. Based on these findings, a strategy is developed for improved propellant-remaining estimation. The first method is based on Boyle's law, which related the values of pressure, volume, and temperature (PVT) of an ideal gas. The PVT method is used for the monopropellant and the bipropellant engines. The second method is based on the engine performance tests, which provide data that relate thrust and specific impulse associated with a propellant tank to that tank's pressure. Two curves representing thrust and specific impulse as functions of pressure are then generated using a polynomial fit on the engine performance data. The third method involves a computer simulation of the propellant system. The propellant flow is modeled by creating a conceptual model of the propulsion system configuration, taking into account such factors as the propellant and pressurant tank characteristics, thruster functionality, and piping layout. Finally, a thrust calibration technique is presented that uses differential correction with the computer simulation method of propellant-remaining modeling. Thrust calibration provides a better assessment of thruster performance and therefore enables a more accurate estimation of propellant consumed during a given maneuver.

  13. 78 FR 18255 - Airworthiness Directives; Hartzell Propeller, Inc. Propellers

    Science.gov (United States)

    2013-03-26

    ... 12866, (2) Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034... Propeller, Inc., 1 Propeller Place, Piqua, OH 45356; phone: 937-778-4200; email: techsupport@hartzellprop... Propeller Inc., 1 Propeller Place, Piqua, OH 45356-2634; phone: 937-778-4379; fax: 937-778-4391;...

  14. Propeller TAP flap

    DEFF Research Database (Denmark)

    Thomsen, Jørn Bo; Bille, Camilla; Wamberg, Peter;

    2013-01-01

    The aim of this study was to examine if a propeller thoracodorsal artery perforator (TAP) flap can be used for breast reconstruction. Fifteen women were reconstructed using a propeller TAP flap, an implant, and an ADM. Preoperative colour Doppler ultrasonography was used for patient selection to...... major complications needing additional surgery. One flap was lost due to a vascular problem. Breast reconstruction can be performed by a propeller TAP flap without cutting the descending branch of the thoracodorsal vessels. However, the authors would recommend that a small cuff of muscle is left around...

  15. PARAMETER DESIGN PROPELLER KAPAL

    Directory of Open Access Journals (Sweden)

    Muhammad Ridwan

    2012-04-01

    Full Text Available   Designer propeller kapal harus mempertimbangkan berbagai parameter untuk menghasilkan bentuk, type dan ukuran propeller yang memiliki nilai  efektifitas dan effisiensi propulsi tinggi. Propulsi kapal merupakan faktor yang mendominasi  operasional kapal, karena pemakaian bahan bakar untuk operasional propulsi kapal merupakan 42% dari total cost operasional kapal dan merupakan added value yang akan diperoleh oleh perusahaan pelayaran. Pertimbangan parameter desain propeller argonomis dapat mendukung tujuan di atas sehingga dapat menurunkan pemakaian bahan bakar hingga 20 % saat kapal dioperaionalkan.

  16. Nitramine Double Base Propellants

    Directory of Open Access Journals (Sweden)

    M. M. Bhalerao

    1996-10-01

    Full Text Available This review paper broadly covers the studies conducted on nitramine double base (DB propellants, particularly in the field of formulations, evaluation, catalysis and combustion mechanism . Addition of RDX and HMX in double base matrix shows relatively low burn rates and high paper index values. Further, the burn rate of this class of propellants enhances in the presence of energetic binders/plasticisers like glycidyl azide polymer. This paper also discusses the combustion mechanism of HMX/RDX-based DB propellants, especially in the presence of catalytic salts. As scanty data is available on extruded nitramine DB propellants, further work is needed in the field of formulation as well as evaluation with a view to generate exhaustive data.

  17. NASA propeller noise research

    Science.gov (United States)

    Greene, G. C.

    1980-01-01

    The research in propeller noise prediction, noise/performance optimization, and interior reduction is described. Selected results are presented to illustrate the status of the technology and the direction of future research.

  18. Self-propelled Chimeras

    OpenAIRE

    Kruk, Nikita; Maistrenko, Yuri; Wenzel, Nicolas; Koeppl, Heinz

    2015-01-01

    We report the appearance of chimera states in a minimal extension of the classical Vicsek model for collective motion of self-propelled particle systems. Inspired by earlier works on chimera states in the Kuramoto model, we introduce a phase lag parameter in the particle alignment dynamics. Compared to the oscillatory networks with fixed site positions, the self-propelled particle systems can give rise to distinct forms of chimeras resembling moving flocks through an incoherent surrounding, f...

  19. Surface piercing propeller performance

    OpenAIRE

    Peterson, Derek T.

    2005-01-01

    This thesis addresses possible improvements in the efficiency (thrust) of surface piercing propellers; in particular with respect to the angle of the propeller shaft came to mind. Preliminary calculations based on the basic pitch/diameter geometry suggest that about 3-5% efficiency is lost if the shaft is parallel to the flow, compared to skewed a few degrees in the "paddlewheel" direction at certain speeds. More accurate calculations based on the lift characteristics of each blade, on the an...

  20. Stochastic flights of propellers

    CERN Document Server

    Pan, Margaret; Chiang, Eugene; Evans, Steven N

    2012-01-01

    Kilometer-sized moonlets in Saturn's A ring create S-shaped wakes called "propellers" in surrounding material. The Cassini spacecraft has tracked the motions of propellers for several years and finds that they deviate from Keplerian orbits having constant semimajor axes. The inferred orbital migration is known to switch sign. We show using a statistical test that the time series of orbital longitudes of the propeller Bl\\'eriot is consistent with that of a time-integrated Gaussian random walk. That is, Bl\\'eriot's observed migration pattern is consistent with being stochastic. We further show, using a combination of analytic estimates and collisional N-body simulations, that stochastic migration of the right magnitude to explain the Cassini observations can be driven by encounters with ring particles 10-20 m in radius. That the local ring mass is concentrated in decameter-sized particles is supported on independent grounds by occultation analyses.

  1. Design Optimization of Propeller Duct

    OpenAIRE

    Aasebø, Steinar Martin

    2009-01-01

    This Master Thesis ends up in a design optimization of a propeller duct profile as an example of multi-objective optimization with computationally expensive objective function evaluation. Computational Fluid Dynamics simulation of the ducted propeller is then done as objective evaluation. Response surface methods are employed in the propeller duct profile optimization.

  2. Low toxicity rocket propellants

    NARCIS (Netherlands)

    Wink, J.

    2014-01-01

    Hydrazine (N2H4) and its hypergolic mate nitrogen tetroxide (N2O4) are used on virtually all spacecraft and on a large number of launch vehicles. In recent years however, there has been an effort in identifying and developing alternatives to replace hydrazine as a rocket propellant.

  3. Propeller design by numerical optimization

    Science.gov (United States)

    Mendoza, J. P.

    1977-01-01

    A computer program designed to optimize propeller characteristics was developed by combining two main programs: the first is the optimization program based on the gradient algorithm; the second is based on a propeller blade element theory and uses an aerodynamics subprogram to approximate the lift and drag characteristics of the NACA 16-series airfoil section. To evaluate the propeller program alone (with its aerodynamics subprogram), propeller characteristics were computed and compared to those from wind tunnel investigations conducted on three different NACA propellers. Although the thrust and power coefficients which were computed using the blade element theory were generally higher than the experimental results for two of the three propellers, the corresponding efficiencies showed good agreement for all three propellers. The propeller optimization program was then used to study the NACA 4-(5)(08)-03 propeller at various Mach numbers from 0.175 to 0.60. Improvements in propeller efficiency and thrust were obtained through the use of the propeller optimization program.

  4. Unsteady propeller hydrodynamics

    OpenAIRE

    Renick, Dirk H.

    2001-01-01

    One of the main problems affecting modern propulsor design engineers is the ability to quantitatively predict unsteady propeller forces for modern, multi-blade row, ducted propulsors operating in highly contracting flowfields. Current algorithms provide valuable insight into qualitative trendlines for these modern designs. This thesis has focused on the more accurate quantitative force prediction by introducing more physical modeling into the numerical computations, using more accurate analyt...

  5. The propeller and the frog

    OpenAIRE

    Pan, Margaret; Chiang, Eugene

    2010-01-01

    "Propellers" in planetary rings are disturbances in ring material excited by moonlets that open only partial gaps. We describe a new type of co-orbital resonance that can explain the observed non-Keplerian motions of propellers. The resonance is between the moonlet underlying the propeller, and co-orbiting ring particles downstream of the moonlet where the gap closes. The moonlet librates within the gap about an equilibrium point established by co-orbiting material and stabilized by the Corio...

  6. Cavitation simulation on marine propellers

    DEFF Research Database (Denmark)

    Shin, Keun Woo

    Cavitation on marine propellers causes thrust breakdown, noise, vibration and erosion. The increasing demand for high-efficiency propellers makes it difficult to avoid the occurrence of cavitation. Currently, practical analysis of propeller cavitation depends on cavitation tunnel test, empirical...... are investigated, and one of the cavitation models is verified for the cavitation simulation on marine propellers. Three cavitation models with a vapor transport equation and a cavitation model with a barotropic state law are implemented in the in-house RANS solver, EllipSys. The numerical results for...

  7. Magnetic propeller outflows

    OpenAIRE

    Lovelace, R. V. E.; Romanova, M. M.; Bisnovatyi-Kogan, G. S.

    1998-01-01

    A model is developed for magnetic `propeller'-driven outflows which cause a rapidly rotating magnetized star accreting from a disk to spin-down. Energy and angular momentum lost by the star goes into expelling most of the accreting disk matter. The theory gives an expression for the effective Alfven radius $R_A$ (where the inflowing matter is effectively stopped) which depends on the mass accretion rate, the star's mass and magnetic moment, and the star's rotation rate. The model points to a ...

  8. Bladelementsanalys – Propeller

    OpenAIRE

    Cagatay, Daniel

    2014-01-01

    Programmet som skapats ger generella approximationer över hur en flygplanspropeller skall dimensioneras. Det kan uppstå skillnader mellan det praktiska och teoretiska värdena hos propellern. Den vingprofil som dimensionerats är FX67-K-170. Ett optimalt tillstånd har beräknats för denna propeller. Propellerverkningsgraden kan vara så högt som 91 % med en relativ hastighet mellan vind och farkost på 86 m/s och med ett varvtal på 1200 rpm. Avanceringstalet beräknas då till 1,44. Torderingen är s...

  9. Modelling of composite propellant properties

    NARCIS (Netherlands)

    Keizers, H.L.J.; Hordijk, A.C.; Vliet, L.D. van; Bouquet, F.

    2000-01-01

    State-of-the-art composite propellants are based on solid particles (AP, Aluminium) in a polymeric HTPB based binder system. The usability of a propellant for a particular application is dependent on a large number of properties. These different properties sometimes result in contradictory requireme

  10. Spectral characterizations of propeller graphs

    OpenAIRE

    Liu, Xiaogang; Zhou, Sanming

    2012-01-01

    A propeller graph is obtained from an $\\infty$-graph by attaching a path to the vertex of degree four, where an $\\infty$-graph consists of two cycles with precisely one common vertex. In this paper, we prove that all propeller graphs are determined by their Laplacian spectra as well as their signless Laplacian spectra.

  11. Cryogenic Propellant Storage and Transfer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Cryogenic Propellant Storage and Transfer project will demonstrate the capability to safely and efficiently store, transfer and measure cryogenic propellants,...

  12. Ignition Studies on Aluminised Propellant.

    Directory of Open Access Journals (Sweden)

    K. A. Bhaskaran

    1996-12-01

    Full Text Available An experimental investigation on the ignition of metallised propellants (APIHTPB/AI has been carried out 10 determine the ignition delay, minimum ignition energy and corresponding heat flux,threshold heat flux for ignition and minimum ignition temperature, Ignition experiments were conductedusing a shock tube under convectiveheating conditions similar to those prevailingin a rocket motor. Heat flux at propellant location was measured by thin film heat flux gauge and also calculated from a ribbon thermocouple output under similar test conditions. The igntion delay was measured as the time lag between the arrival of hot gas at the propellant and the light emission due to actual ignition of the propellant. The experimental results indicate that the ignition delay characteristics are independent of pressure. The minimum energy for ignition obtained for the propellant is 1100J/m2 corresponding to the heat flux range of 80·120 WIcm2 for a gas velocity of 110 mls. The threshold heat flux required to ignite the propellant was 40 W/cm2 at a velocity of 110 mls. Heat flux corresponding to minimum ignition energy and the threshold heat flux increase with gas velocity. The threshold ignition temperature of the propellant was found to be 600 ± 20 K.

  13. Beta Thalassemia

    Science.gov (United States)

    ... South Asian (Indian, Pakistani, etc.), Southeast Asian and Chinese descent. 1 Beta Thalassemia ßß Normal beta globin ... then there is a 25% chance with each pregnancy that their child will inherit two abnormal beta ...

  14. Magnetic propeller in symbiotic stars

    OpenAIRE

    Panferov, Alexander; Mikolajewski, Maciej

    2000-01-01

    Rapidly spinning magnetic white dwarfs in symbiotic stars may pass through the propeller stage. It is believed that a magnetic propeller acts in two such stars CH Cyg and MWC 560. We review a diversity of manifestations of the propeller there. In these systems in a quiescent state the accretion onto a white dwarf from the strong enough wind of a companion star is suppressed by the magnetic field, and the hot component luminosity is low. Since the gas stored in the envelope eventually settles ...

  15. Recent tendency of technology on marine propeller; Saikin ni okeru propeller gijutsu no doko

    Energy Technology Data Exchange (ETDEWEB)

    Yoshioka, M

    1998-09-01

    This paper reviews the recent development of marine propellers and their computerized planning and manufacturing systems. A recent propeller planning system is explained first showing a figure. Propeller theories are then described. Low speed large propellers, high efficiency propellers with reduced are blades, and other types of energy saving propeller devices and appendages, such as contra-rotating propellers, propeller boss cap fins, contracted loaded tip propellers, tandem propellers, and etc. are described under the heading of energy saving propellers. The paper reports also the present state of cavitation, vibromotive force, singing, material and strength, and fitting methods of propellers. The manufacturing technology of propellers is dealt with dividing into the following headings, viz. Forging, NC blade surface machining, Grinding and polishing, and inspection. 17 refs., 14 figs.

  16. Liquid Propellants for Advanced Gun Ammunitions

    Directory of Open Access Journals (Sweden)

    K. P. Rao

    1987-01-01

    Full Text Available With constant improvements, the conventional solid propellants for guns have almost reached their limit in performance. Liquid gun propellants are promising new comers capable of surpassing these performance limits and have numerous advantages over solid propellants. A method has been worked out to predict the internal ballistics of a liquid propellant gun and illustrated in a typical application.

  17. Liquid Propellants for Advanced Gun Ammunitions

    OpenAIRE

    K. P. Rao; A. S. Bartakke; R.G.K. Nair

    1987-01-01

    With constant improvements, the conventional solid propellants for guns have almost reached their limit in performance. Liquid gun propellants are promising new comers capable of surpassing these performance limits and have numerous advantages over solid propellants. A method has been worked out to predict the internal ballistics of a liquid propellant gun and illustrated in a typical application.

  18. Alternate Propellant Thermal Rocket Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Alternate Propellant Thermal Rocket (APTR) is a novel concept for propulsion of space exploration or orbit transfer vehicles. APTR propulsion is provided by...

  19. Propellant gaging for geostationary satellites

    Science.gov (United States)

    Orazietti, A. J.; Orton, G. F.; Schreib, R.

    1986-06-01

    Evaluations were performed to select four gaging concepts for ground tests and low-g tests in the NASA KC-135 aircraft. The selected concepts were an ultrasonic point sensor system, a nucleonic gaging system, an ultrasonic torsional wave guide, and an ultrasonic flowmeter. The first three systems provide a direct measurement of propellant quantity remaining, while the fourth system integrates (totalizes) the propellant flow to the engines and infers propellant remaining based on a known initial propellant load. As a result of successful ground and KC-135 tests, two concepts (the ultrasonic point sensor and nucleonic systems) were selected for orbital test in a Shuttle Get-Away-Special experiment. These systems offer high end-of-life accuracy potential, are nonintrusive (external to the tanks and feedlines), and are low in risk because of their good technology base. The Shuttle Get-Away-Special experiment has been assembled and passed flight certification testing in late April 1986.

  20. DESIGN EKONOMIS UNTUK PROPELLER KAPAL

    Directory of Open Access Journals (Sweden)

    Hartono Hartono

    2012-02-01

    Full Text Available Increase of the price of world oil pushs liner to conduct action is economic from every operational unit in it’sship armada. One other most dominant in usage of fuel is Main engine is working to turn around propeller asship actuator. On that account ship owner wants design propeller which is economic for it’s ship to canreduce usage of fuel of 20% when sailing.

  1. Trans-sonic propeller stage

    OpenAIRE

    Popov, S.B.; Prokhorov, M. E.

    2004-01-01

    We follow the approach used by Davies and Pringle (1981) and discuss the trans-sonic substage of the propeller regime. This substage is intermediate between the supersonic and subsonic propeller substages. In the trans-sonic regime an envelope around a magnetosphere of a neutron star passes through a kind of a reorganization process. The envelope in this regime consists of two parts. In the bottom one turbulent motions are subsonic. Then at some distance $r_\\mathrm{s}$ the turbulent velocity ...

  2. DESIGN EKONOMIS UNTUK PROPELLER KAPAL

    OpenAIRE

    Hartono Hartono

    2012-01-01

    Increase of the price of world oil pushs liner to conduct action is economic from every operational unit in it’sship armada. One other most dominant in usage of fuel is Main engine is working to turn around propeller asship actuator. On that account ship owner wants design propeller which is economic for it’s ship to canreduce usage of fuel of 20% when sailing.

  3. Contra rotative propeller performance estimation

    OpenAIRE

    Coca Casanueva, Vladimir

    2008-01-01

    Due to the continuous increase in the fuel price, the propeller engine solution (the most efficient in fuel saving terms) becomes very attractive to airlines and thus, to aircraft manufacturers. However, airlines aren’t ready to fly an aircraft at lower cruise Mach number than the traditional Mach 0,84, which jeopardizes the fuel efficiency of propellers. At this stage is where the contra-rotative concept appears, which let us to increase the cruise speed while reducing fuel consumption...

  4. Aircraft Propeller Hub Repair

    Energy Technology Data Exchange (ETDEWEB)

    Muth, Thomas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peter, William H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-02-13

    The team performed a literature review, conducted residual stress measurements, performed failure analysis, and demonstrated a solid state additive manufacturing repair technique on samples removed from a scrapped propeller hub. The team evaluated multiple options for hub repair that included existing metal buildup technologies that the Federal Aviation Administration (FAA) has already embraced, such as cold spray, high velocity oxy-fuel deposition (HVOF), and plasma spray. In addition the team helped Piedmont Propulsion Systems, LLC (PPS) evaluate three potential solutions that could be deployed at different stages in the life cycle of aluminum alloy hubs, in addition to the conventional spray coating method for repair. For new hubs, a machining practice to prevent fretting with the steel drive shaft was recommended. For hubs that were refurbished with some material remaining above the minimal material condition (MMC), a silver interface applied by an electromagnetic pulse additive manufacturing method was recommended. For hubs that were at or below the MMC, a solid state additive manufacturing technique using ultrasonic welding (UW) of thin layers of 7075 aluminum to the hub interface was recommended. A cladding demonstration using the UW technique achieved mechanical bonding of the layers showing promise as a viable repair method.

  5. Aspects of Propeller Developements for a Submarine

    DEFF Research Database (Denmark)

    Andersen, Poul; kappel, Jens Julius; Spangenberg, Eugen

    2009-01-01

    Design and development of propellers for submarines are in some ways different from propellers for surface vessels. The most important demand is low acoustic signature that has priority over propeller efficiency, and the submarine propeller must be optimized with respect to acoustics rather than...... efficiency. Moreover the operating conditions of a submarine propeller are quite different. These aspects are discussed as well as the weighing of the various propeller parameters against the design objectives. The noise generated by the propeller can be characterized as thrust noise due to the inhomogeneous...... wake field of the submarine, trailing-edge noise and noise caused by turbulence in the inflow. The items discussed are demonstrated in a case study where a propeller of the Kappel type was developed. Three stages of the development are presented, including a design of an 8-bladed propeller where the...

  6. Experimental Performance of a Novel Trochoidal Propeller

    Science.gov (United States)

    Roesler, Bernard; Epps, Brenden

    2015-11-01

    In the quest for energy efficiency in marine transportation, a promising marine propulsor concept is the trochoidal propeller. We have designed and tested a novel trochoidal propeller using a sinusoidal blade pitch function. The main results presented are measurements of thrust and torque, as well as the calculated efficiency, for a range of advance coefficients. The experimental data show narrow 95% confidence bounds, demonstrating high accuracy and repeatability in the experimental methods. We compare our sinusoidal-pitch trochoidal propeller with prior cross-flow propellers, as well as a representative screw propeller. While the efficiency of our propeller exceeds that of the cycloidal-pitch trochoidal propeller, it is slightly lower than the efficiencies of the other propellers considered. We also present a theoretical model that can be used to further explore and optimize such trochoidal propellers, leading to new avenues for improvements in marine propulsion systems.

  7. Chaotic dynamics of propeller singing

    Institute of Scientific and Technical Information of China (English)

    YU Dapeng; ZHAO Deyou; WANG Yu

    2012-01-01

    The system of propeller singing is proved for the first time to have the character of chaotic dynamics through the study of the signal time series. The estimation of the topolog- ical dimension, the confirmation of the number of independent variable and the description of the character of attractor trajectory in reconstructed phase space are implemented during the analysis of the system. The result indicates that the system of propeller singing can be recon- structed by the optional delay time tD = 1, the minimal embedding dimension dE = 8, and the reconstructed topological parameter with the fractional correlation dimension D2 = 5.1579 and the positive maximum Lyapunov exponent λtD=0.0771. The results provide a new approach to the further study of the propeller singing phenomenon.

  8. Mars Integrated Propellant Production System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Integrated Mars In-Situ Propellant Production System (IMISPPS) is an end-to-end system that will produce rocket propellant on Mars from CO2 in the Martian...

  9. 78 FR 45052 - Airworthiness Directives; Hartzell Propeller, Inc. Propellers

    Science.gov (United States)

    2013-07-26

    ... specified products. The NPRM published in the Federal Register on March 26, 2013 (78 FR 18255). The NPRM... considered the comment received. Hartzell Propeller, Inc. supports the NPRM (78 FR 18255, dated March 26... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), (3) Will...

  10. Surface hardening characteristics of aluminium bronze for marine propeller; Senpaku propeller yo aluminium seido no hyomen koka tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Kawazoe, T. [Nagasaki University, Nagasaki (Japan). Faculty of Engineering; Furukawa, T.; Kanda, K.; Nishikido, S. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1997-05-25

    With a marine propeller material AlBC3 as the object of discussion, three kinds of surface hardening tests and a cavitation erosion test were carried out to investigate the relationship among hardenability, microstructures and erosion resistance. Surface hardness of each hardened material was found about 1.5 times greater for water-sprayed flame hardening, about 1.6 times greater for laser hardening, and about 1.3 times greater for high-frequency hardening than that of as-cast materials. The hardness is closely related with the microstructures. In the flame hardening, a hard ({beta}+{beta}prime) phase is distributed in a great quantity on the surface, and the occupying ratio of a soft {alpha} phase increases as the depth increases. In the laser hardening, a micronized {beta} phase is distributed all over the surface, contributing to increase in the surface hardness. Weight loss in the flame-hardened materials due to erosion has stayed at about 35% of that for as-cast materials, showing improvement in the erosion resistance. If the surface hardening process verified by the present test is applied to production propellers, the water-sprayed flame hardening process is thought most suitable when the surface hardness, hardened layer thickness and workability are considered. 8 refs., 17 figs., 4 tabs.

  11. Innovative boron nitride-doped propellants

    OpenAIRE

    Thelma Manning; Richard Field; Kenneth Klingaman; Michael Fair; John Bolognini; Robin Crownover; Carlton P. Adam; Viral Panchal; Eugene Rozumov; Henry Grau; Paul Matter; Michael Beachy; Christopher Holt; Samuel Sopok

    2016-01-01

    The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN) is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P). Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower ...

  12. Unconventional Propeller Tip Design - Hydrodynamic Study

    OpenAIRE

    Ommundsen, Andreas

    2015-01-01

    Winglets have been successful in the aircraft industry, but have not yet seen widespread use on marine propellers. Three different propellers (one conventional and two equipped with winglets) have been modelled and analysed with the CFD software STAR-CCM+. The winglet propellers achieved up to 40 % greater thrust than the conventional propeller at the operational propulsion point, but the torque increased even more - meaning that the overall open water efficiency was reduced by as much as...

  13. Innovative boron nitride-doped propellants

    Directory of Open Access Journals (Sweden)

    Thelma Manning

    2016-04-01

    Full Text Available The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P. Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower flame temperatures for gun barrels. Further, boron can dope steel, which drastically improves its strength and wear resistance, and can block the formation of softer carbides. A scalable synthesis method for producing boron nitride nano-particles that can be readily dispersed into propellants has been developed. Even dispersion of the nano-particles in a double-base propellant has been demonstrated using a solvent-based processing approach. Stability of a composite propellant with the BN additive was verified. In this paper, results from propellant testing of boron nitride nano-composite propellants are presented, including closed bomb and wear and erosion testing. Detailed characterization of the erosion tester substrates before and after firing was obtained by electron microscopy, inductively coupled plasma and x-ray photoelectron spectroscopy. This promising boron nitride additive shows the ability to improve gun wear and erosion resistance without any destabilizing effects to the propellant. Potential applications could include less erosive propellants in propellant ammunition for large, medium and small diameter fire arms.

  14. Pyrotechnic Igniters for Liquid Propellant Gun .

    OpenAIRE

    D. K. Kharat; K. J. Daniel; K. R. Rao; A. A. Ghosh; Shah, S.T.; S. C. Mitra

    1997-01-01

    The results of a preliminary investigation on the use of liquid propellant for gun application are presented. Both regenerative and bulk loaded liquid propellant guns were used in the study.Pyrotechnic igniters were tried out for igniting the liquid propellant. Existing pyrotechnic igniters were suitably modified to obtain pressure beyond 20 MPa in less than 3 ms in the combustion chamber.

  15. Innovative boron nitride-doped propellants

    Institute of Scientific and Technical Information of China (English)

    Thelma MANNING; Henry GRAU; Paul MATTER; Michael BEACHY; Christopher HOLT; Samuel SOPOK; Richard FIELD; Kenneth KLINGAMAN; Michael FAIR; John BOLOGNINI; Robin CROWNOVER; Carlton P. ADAM; Viral PANCHAL; Eugene ROZUMOV

    2016-01-01

    The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN) is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P). Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower flame temperatures for gun barrels. Further, boron can dope steel, which drastically improves its strength and wear resistance, and can block the formation of softer carbides. A scalable synthesis method for producing boron nitride nano-particles that can be readily dispersed into propellants has been developed. Even dispersion of the nano-particles in a double-base propellant has been demonstrated using a solvent-based processing approach. Stability of a composite propellant with the BN additive was verified. In this paper, results from propellant testing of boron nitride nano-composite propellants are presented, including closed bomb and wear and erosion testing. Detailed characterization of the erosion tester substrates before and after firing was obtained by electron microscopy, inductively coupled plasma and x-ray photoelectron spectroscopy. This promising boron nitride additive shows the ability to improve gun wear and erosion resistance without any destabilizing effects to the propellant. Potential applications could include less erosive propellants in propellant ammunition for large, medium and small diameter fire arms.

  16. 14 CFR 35.2 - Propeller configuration.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller configuration. 35.2 Section 35.2 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS General § 35.2 Propeller configuration. The applicant must provide a list of all the components, including references...

  17. Plasma ignition of LOVA propellants

    NARCIS (Netherlands)

    Driel, C.A. van; Boluijt, A.G.; Schilt, A.

    2010-01-01

    Ignition experiments were performed using a gun simulator which is equipped with a burst disk. This equipment facilitates the application of propellant loading densities which are comparable to those applied in regular ammunitions. For this study the gun simulator was equipped with a plasma jet igni

  18. The propeller and the frog

    CERN Document Server

    Pan, Margaret

    2010-01-01

    "Propellers" in planetary rings are disturbances in ring material excited by moonlets that open only partial gaps. We describe a new type of co-orbital resonance that can explain the observed non-Keplerian motions of propellers. The resonance is between the moonlet underlying the propeller, and co-orbiting ring particles downstream of the moonlet where the gap closes. The moonlet librates within the gap about an equilibrium point established by co-orbiting material and stabilized by the Coriolis force. In the limit of small libration amplitude, the libration period scales linearly with the gap azimuthal width and inversely as the square root of the co-orbital mass. The new resonance recalls but is distinct from conventional horseshoe and tadpole orbits; we call it the "frog" resonance, after the relevant term in equine hoof anatomy. For a ring surface density and gap geometry appropriate for the propeller Bl\\'eriot in Saturn's A ring, our theory predicts a libration period of ~4 years, similar to the ~3.7 yea...

  19. Drag and Torque on Locked Screw Propeller

    Directory of Open Access Journals (Sweden)

    Tomasz Tabaczek

    2014-09-01

    Full Text Available Few data on drag and torque on locked propeller towed in water are available in literature. Those data refer to propellers of specific geometry (number of blades, blade area, pitch and skew of blades. The estimation of drag and torque of an arbitrary propeller considered in analysis of ship resistance or propulsion is laborious. The authors collected and reviewed test data available in the literature. Based on collected data there were developed the empirical formulae for estimation of hydrodynamic drag and torque acting on locked screw propeller. Supplementary CFD computations were carried out in order to prove the applicability of the formulae to modern moderately skewed screw propellers.

  20. Evaluation of PROPELLER MR imaging. Preliminary experiences

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Harushi; Aoki, Shigeki; Abe, Osamu [Tokyo Univ. (Japan). Hospital] [and others

    2002-05-01

    Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction (PROPELLER) MR imaging (MRI) has a unique ability to correct motion artifacts and is expected to be useful in diffusion-weighted MRI. This article describes preliminary experiences with PROPELLER MRI. PROPELLER uses a radial scan variation of the fast spin-echo sequence and it shows much less spatial deterioration than the echo-planar imaging sequence. To determine the optimal parameters of this technique, we calculated the signal intensities of phantoms and brains in various settings. PROPELLER MR examinations were also performed in 66 patients for clinical use. PROPELLER MRI appears to be a promising and useful technique. (author)

  1. Electromechanical propellant control system actuator

    Science.gov (United States)

    Myers, W. Neill; Weir, Rae Ann

    1990-01-01

    New control mechanism technologies are currently being sought to provide alternatives to hydraulic actuation systems. The Propulsion Laboratory at Marshall Space Flight Center (MSFC) is involved in the development of electromechanical actuators (EMA's) for this purpose. Through this effort, an in-house designed electromechanical propellant valve actuator has been assembled and is presently being evaluated. This evaluation will allow performance comparisons between EMA and hydraulics systems. The in-house design consists of the following hardware: a three-phase brushless motor, a harmonic drive, and an output spline which will mate with current Space Shuttle Main Engine (SSME) propellant control valves. A resolver and associated electronics supply position feedback for the EMA. System control is provided by a solid-state electronic controller and power supply. Frequency response testing has been performed with further testing planned as hardware and test facilities become available.

  2. Propeller Study. Part 2: the Design of Propellers for Minimum Noise

    Science.gov (United States)

    Ormsbee, A. I.; Woan, C. J.

    1977-01-01

    The design of propellers which are efficient and yet produce minimum noise requires accurate determinations of both the flow over the propeller. Topics discussed in relating aerodynamic propeller design and propeller acoustics include the necessary approximations and assumptions involved, the coordinate systems and their transformations, the geometry of the propeller blade, and the problem formulations including the induced velocity, required in the determination of mean lines of blade sections, and the optimization of propeller noise. The numerical formulation for the lifting-line model are given. Some applications and numerical results are included.

  3. Self-Propelled Leidenfrost Droplets

    Science.gov (United States)

    Linke, H.; Alemán, B. J.; Melling, L. D.; Taormina, M. J.; Francis, M. J.; Dow-Hygelund, C. C.; Narayanan, V.; Taylor, R. P.; Stout, A.

    2006-04-01

    We report that liquids perform self-propelled motion when they are placed in contact with hot surfaces with asymmetric (ratchetlike) topology. The pumping effect is observed when the liquid is in the Leidenfrost regime (the film-boiling regime), for many liquids and over a wide temperature range. We propose that liquid motion is driven by a viscous force exerted by vapor flow between the solid and the liquid.

  4. Design of Multi-Propellant Star Grains for Solid Propellant Rockets

    Directory of Open Access Journals (Sweden)

    S. Krishnan

    1980-01-01

    Full Text Available A new approach to solve the geometry-problem of solid propellant star is presented. The basis of the approach is to take the web-thickness (a ballistic as well as a geometrical property as the characteristic length. The nondimensional characteristic parameters representing diameter, length, slenderness-ratio, and ignitor accommodation of the grain are all identified. Many particular cases of star configurations (from the configurations of single propellant to those of four different propellants can be analysed through the identified characteristic parameters. A better way of representing the single-propellant-star-performance in a design graph is explained. Two types of dual propellant grains are analysed in detail. The first type is characterised by its two distinct stages of burning (initially by single propellant burning and then by dual propellant burning; the second type has the dual propellant burning throughout. Suitability of the identified characteristic parameters to an optimisation study is demonstrated through examples.

  5. High Performance Binder for EMCDB Propellants

    Directory of Open Access Journals (Sweden)

    V. K. Bhat

    1995-01-01

    Full Text Available A novel block polymer has been synthesised from caprolactone using hydroxy terminated polybutadiene as ring opening initiator. Usefulness of this polymer as propellant binder has been studied by generating data on physico-chemical properties of the polymer. The polymer exhibited high miscibility with nitrate ester and high solid loading capability. Preliminary data generated on typical propellant formulation indicated higher performance as compared to composite propellant.

  6. Pyrotechnic Igniters for Liquid Propellant Gun .

    Directory of Open Access Journals (Sweden)

    D. K. Kharat

    1997-04-01

    Full Text Available The results of a preliminary investigation on the use of liquid propellant for gun application are presented. Both regenerative and bulk loaded liquid propellant guns were used in the study.Pyrotechnic igniters were tried out for igniting the liquid propellant. Existing pyrotechnic igniters were suitably modified to obtain pressure beyond 20 MPa in less than 3 ms in the combustion chamber.

  7. Shrinkage in propellant Manufactured by Solvent Process

    Directory of Open Access Journals (Sweden)

    K.M. Agrawal

    1991-04-01

    Full Text Available The propellant manufacturers select the dimensions of die-pin for extrusion of dough by trial and error method based on their experience. This paper presents a general equation applicable for any propellant composition processed by solvent process, in any shape, i.e., cord, monotubular or the multitubular. To illustrate the relationship, calculation for outer radius for a few typical single-base propellants is given.

  8. Sound signature of propeller tip vortex cavitation

    OpenAIRE

    Pennings, P.C.; Westerweel, J.; Van Terwisga, T.J.C.

    2015-01-01

    The design of an efficient propeller is limited by the harmful effects of cavitation. The insuffcient understanding of the role of vortex cavitation in noise and vibration reduces the maximum effciency by a necessary safety margin. The aim in the present study is to directly relate propeller cavitation sound to tip vortex cavity dynamics. This is achieved by a dedicated experiment in a cavitation tunnel on a specially designed two-bladed propeller using a high-speed video camera and a hydroph...

  9. Drag and Torque on Locked Screw Propeller

    OpenAIRE

    Tomasz Tabaczek; T. Bugalski

    2014-01-01

    Few data on drag and torque on locked propeller towed in water are available in literature. Those data refer to propellers of specific geometry (number of blades, blade area, pitch and skew of blades). The estimation of drag and torque of an arbitrary propeller considered in analysis of ship resistance or propulsion is laborious. The authors collected and reviewed test data available in the literature. Based on collected data there were developed the empirical formulae for estimation of hydro...

  10. Electrochemical corrosion studies in low conductivity propellants

    Science.gov (United States)

    Blue, G. D.; Moran, C. M.; Distefano, S.

    1986-01-01

    The Jet Propulsion Laboratory is investigating the possibility of developing advanced electrochemical techniques as accelerated compatibility tests for metal/propellant systems which overcome the problems associated with the low conductivity of the liquid propellants (e.g., hydrazines, nitrogen tetroxide). Both DC techniques and AC electrochemical impedance spectroscopy are being evaluated. Progress has been made in experiments involving stainless steel with hydrazine and nitrogen tetroxide propellants.

  11. Simulasi Tegangan Propeller Al – Mg yang Dirancang untuk Propeller Rendah Bising

    OpenAIRE

    Aldiansyah, Yogi

    2015-01-01

    To facilitate getting stress, strain and deformation that occurs in the propeller blades and the flow simulation of structural static that is the purpose of this study. usefulness of doing this simulation is to obtain the value of stress, strain and deformation that occurs in every element of the propeller. In this case each part of the propeller will get adifferent stress at each point. In simulating the propeller researcher using theANSYS15.0softwarethat isfluentandstructuralstaticfluidvelo...

  12. High Seed Compressor for Propellant Densification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Propellant densification systems particularly for H2 require compression systems developing very large amounts of head. Development of this head requires multiple...

  13. Low speed propellers: Impact of advanced technologies

    Science.gov (United States)

    Keiter, I. D.

    1980-01-01

    Sensitivity studies performed to evaluate the potential of several advanced technological elements on propeller performance, noise, weight, and cost for general aviation aircraft are discussed. Studies indicate that the application of advanced technologies to general aviation propellers can reduce fuel consumption in future aircraft an average of ten percent, meeting current regulatory noise limits. Through the use of composite blade construction, up to 25 percent propeller weight reduction can be achieved. This weight reduction in addition to seven percent propeller efficiency improvements through application of advanced technologies result in four percent reduction in direct operating costs, ten percent reduction in aircraft acquisition cost, and seven percent lower gross weight for general aviation aircraft.

  14. Low-g propellant gaging

    Science.gov (United States)

    Orton, George

    1987-09-01

    A program to develop and demonstrate technology for low gravity propellant gaging on future geostationary satellites is described. Evaluations were performed to select four gaging concepts for ground tests and low gravity tests in the NASA KC-135 aircraft. The selected concepts were: (1) an ultrasonic point sensor system, (2) a nucleonic gaging system, (3) an ultrasonic torsional wave guide, and (4) an ultrasonic flowmeter. As a result of successful ground and KC-135 tests, two concepts (the ultrasonic point sensor and the nucleonic systems) were selected for orbital test in a shuttle Get-Away-Special experiment.

  15. Green plasticizers for multibase gun propellants (Lecture)

    NARCIS (Netherlands)

    Schoolderman, C.; Driel, C.A. van; Zebregs, M.

    2007-01-01

    TNO Defence, Security and Safety has a long history of research on gun propellants. Areas investigated are formulating (new ingredients, optimization), manufacturing, charge design and lifetime assessment [1,2,3,4,5]. In conventional propellants inert plasticizers are used to alter performance, proc

  16. 14 CFR 23.925 - Propeller clearance.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller clearance. 23.925 Section 23.925 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless...

  17. 14 CFR 25.929 - Propeller deicing.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller deicing. 25.929 Section 25.929 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.929 Propeller deicing. (a) For airplanes intended for use where icing may...

  18. 14 CFR 25.925 - Propeller clearance.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller clearance. 25.925 Section 25.925 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated,...

  19. KAPPEL Propeller. Development of a Marine Propeller with Non-planar Lifting Surfaces

    DEFF Research Database (Denmark)

    Kappel, J.; Andersen, Poul

    2002-01-01

    The principle of non-planar lifting surfaces is applied to the design of modern aircraft wings to obtain better lift to drag ratios. Whereas a pronounced fin or "winglet" at the wingtip has been developed for aircraft, the application of the non-planar principle to marine propellers, dealt with in...... this paper, has led to the KAPPEL propeller with blades curved towards the suction side integrating the fin or winglet into the propeller blade. The combined theoretical, experimental and practical approach to develop and design marine propellers with non-planar lifting surfaces has resulted in...... propellers with higher efficiency and lower levels of noise and vibration excitation compared to conventional propellers designed for the same task. Conventional and KAPPEL propellers have been compared for a medium sized container ship and a product tanker. In total nine of these unconventional and two...

  20. Application of an optimization method to high performance propeller designs

    Science.gov (United States)

    Li, K. C.; Stefko, G. L.

    1984-01-01

    The application of an optimization method to determine the propeller blade twist distribution which maximizes propeller efficiency is presented. The optimization employs a previously developed method which has been improved to include the effects of blade drag, camber and thickness. Before the optimization portion of the computer code is used, comparisons of calculated propeller efficiencies and power coefficients are made with experimental data for one NACA propeller at Mach numbers in the range of 0.24 to 0.50 and another NACA propeller at a Mach number of 0.71 to validate the propeller aerodynamic analysis portion of the computer code. Then comparisons of calculated propeller efficiencies for the optimized and the original propellers show the benefits of the optimization method in improving propeller performance. This method can be applied to the aerodynamic design of propellers having straight, swept, or nonplanar propeller blades.

  1. Propellant isolation shutoff valve program

    Science.gov (United States)

    Merritt, F. L.

    1973-01-01

    An analysis and design effort directed to advancing the state-of-the-art of space storable isolation valves for control of flow of the propellants liquid fluorine/hydrazine and Flox/monomethylhydrazine is discussed. Emphasis is on achieving zero liquid leakage and capability of withstanding missions up to 10 years in interplanetary space. Included is a study of all-metal poppet sealing theory, an evaluation of candidate seal configurations, a valve actuator trade-off study and design description of a pneumo-thermally actuated soft metal poppet seal valve. The concepts and analysis leading to the soft seal approach are documented. A theoretical evaluation of seal leakage versus seal loading, related finishes and yield strengths of various materials is provided. Application of a confined soft aluminum seal loaded to 2 to 3 times yield strength is recommended. Use of either an electro-mechanical or pneumatic actuator appears to be feasible for the application.

  2. Performance prediction method for contrarotating propeller ships; Niju hanten propeller sen no bariki suiteiho

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, S. [Kinki Univ., Osaka (Japan); Fujino, R. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1998-06-01

    This paper explains a model test as the base for performance prediction method for contrarotating propeller ships, and the method for analysis thereof. The paper particularly shows a method to derive mutual interference components caused by fore and aft propellers with the effective following wave rate. It then clarifies reasonableness of this method as a result of discussing the results of tests on two model ships. Subsequently, it shows a method to estimate the horse power of an actual ship by extrapolating the results of the model test from a standpoint that the fore and aft propellers in the contrarotaing propeller are handled as one thrusting device, respectively. Furthermore, horse power of two actual ships was estimated based on this estimation method, which made the following matters clear: difference of propeller loads in the model ship and the actual ship has large effects on propeller interference components of effective following wake rate and delivered horse power; and in contrast, effects of distribution of rudder components of effective following wake rate to the fore and aft propellers are small on the propeller interference components of effective following wake rate and the delivered horse power. In contrast to this estimation method, the conventional horse power estimation method which regards the contrarotating propeller as one thrusting device makes worse the balance of loading burdens on the fore and aft propellers, and increases the estimation error. 9 refs., 6 figs., 5 tabs.

  3. Propellant Chemistry for CFD Applications

    Science.gov (United States)

    Farmer, R. C.; Anderson, P. G.; Cheng, Gary C.

    1996-01-01

    Current concepts for reusable launch vehicle design have created renewed interest in the use of RP-1 fuels for high pressure and tri-propellant propulsion systems. Such designs require the use of an analytical technology that accurately accounts for the effects of real fluid properties, combustion of large hydrocarbon fuel modules, and the possibility of soot formation. These effects are inadequately treated in current computational fluid dynamic (CFD) codes used for propulsion system analyses. The objective of this investigation is to provide an accurate analytical description of hydrocarbon combustion thermodynamics and kinetics that is sufficiently computationally efficient to be a practical design tool when used with CFD codes such as the FDNS code. A rigorous description of real fluid properties for RP-1 and its combustion products will be derived from the literature and from experiments conducted in this investigation. Upon the establishment of such a description, the fluid description will be simplified by using the minimum of empiricism necessary to maintain accurate combustion analyses and including such empirical models into an appropriate CFD code. An additional benefit of this approach is that the real fluid properties analysis simplifies the introduction of the effects of droplet sprays into the combustion model. Typical species compositions of RP-1 have been identified, surrogate fuels have been established for analyses, and combustion and sooting reaction kinetics models have been developed. Methods for predicting the necessary real fluid properties have been developed and essential experiments have been designed. Verification studies are in progress, and preliminary results from these studies will be presented. The approach has been determined to be feasible, and upon its completion the required methodology for accurate performance and heat transfer CFD analyses for high pressure, tri-propellant propulsion systems will be available.

  4. New Delivery Systems and Propellants

    Directory of Open Access Journals (Sweden)

    Myrna Dolovich

    1999-01-01

    Full Text Available The removal of chlorofluorocarbon (CFC propellants from industrial and household products has been agreed to by over 165 countires of which more than 135 are developing countries. The timetable for this process is outlined in the Montreal Protocol on Substances that Deplete the Ozone Layer document and in several subsequent amendments. Pressured metered dose inhalers (pMDIs for medical use have been granted temporary exemptions until replacement formulations, providing the same medication via the same route, and with the same efficacy and safety profiles, are approved for human use. Hydrofluoroalkanes (HFAs are the alternative propellants for CFCs-12 and -114. Their potential for damage to the ozone layer is nonexistent, and while they are greenhouse gases, their global warming potential is a fraction (one-tenth of that of CFCs. Replacement formulations for almost all inhalant respiratory medications have been or are being produced and tested; in Canada, it is anticipated that the transition to these HFA or CFC-free pMDIs will be complete by the year 2005. Initially, an HFA pMDI was to be equivalent to the CFC pMDI being replaced, in terms of aerosol properties and effective clinical dose. However, this will not necessarily be the situation, particularly for some corticosteroid products. Currently, only one CFC-free formulation is available in Canada – Airomir, a HFA salbutamol pMDI. This paper discusses the in vitro aerosol characteristics, in vivo deposition and clinical data for several HFA pMDIs for which there are data available in the literature. Alternative delivery systems to the pMDI, namely, dry powder inhalers and nebulizers, are briefly reviewed.

  5. Energy coefficients for a propeller series

    DEFF Research Database (Denmark)

    Olsen, Anders Smærup

    2004-01-01

    The efficiency for a propeller is calculated by energy coefficients. These coefficients are related to four types of losses, i.e. the axial, the rotational, the frictional, and the finite blade number loss, and one gain, i.e. the axial gain. The energy coefficients are derived by use of the...... potential theory with the propeller modelled as an actuator disk. The efficiency based on the energy coefficients is calculated for a propeller series. The results show a good agreement between the efficiency based on the energy coefficients and the efficiency obtained by a vortex-lattice method....

  6. 14 CFR 35.43 - Propeller hydraulic components.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller hydraulic components. 35.43... AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.43 Propeller hydraulic components. Applicants must show by test, validated analysis, or both, that propeller components that contain...

  7. 14 CFR 35.5 - Propeller ratings and operating limitations.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller ratings and operating limitations. 35.5 Section 35.5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS General § 35.5 Propeller ratings and operating limitations. (a) Propeller ratings and...

  8. Gelled Propellants for Reduced Temperature Operation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is responsive to NASA 2004 SBIR objectives (under Topic X6.05) seeking gelled propellant formulations "for long-duration missions involving low-power...

  9. High Speed Compressor for Subcooling Propellants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Propellant densification systems for LH2 require compression systems that develop significant head. In the past this has required multiple stages of compressors...

  10. Some typical solid propellant rocket motors

    NARCIS (Netherlands)

    Zandbergen, B.T.C.

    2013-01-01

    Typical Solid Propellant Rocket Motors (shortly referred to as Solid Rocket Motors; SRM's) are described with the purpose to form a database, which allows for comparative analysis and applications in practical SRM engineering.

  11. High Speed Compressor for Subcooling Propellants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The most promising propellant subcooling systems for LH2 require compression systems that involve development of significant head. The inlet pressure for these...

  12. Nonlinear stability of solid propellant combustion

    OpenAIRE

    Higuera Antón, Francisco; Liñán Martínez, Amable

    1986-01-01

    The stability and transient response of solid propellant combustion has received considerable attention in the literature, using, after Zeldovich (1942 and 1964) and Denison and Baum (1961), the quasisteady approximation for the gas phase. This approximation results from the small value of the ratio of gas-to-solid densities. The analysis of the stability of a simple model of solid propellant combustion is given here. The model includes a surface pyrolisis reaction and a gas phase r...

  13. Active Noise Control in Propeller Aircraft

    OpenAIRE

    Johansson, Sven; Claesson, Ingvar

    2001-01-01

    A noisy environment dominated by low frequency noise can often be improved through the use of active noise control. This situation arises naturally in propeller aircraft where the propellers induce periodic low frequency noise inside the cabin. The cabin noise is typically rather high, and the passenger flight comfort could be improved considerably if this level were significantly reduced. This paper addresses same design aspects for multiple-reference active noise control systems based on th...

  14. Propeller performance analysis using lifting line theory

    OpenAIRE

    Flood, Kevin M.

    2009-01-01

    CIVINS Approved for public release, distribution unlimited Propellers are typically optimized to provide the maximum thrust for the minimum torque at a specific number of revolutions per minute (RPM) at a particular ship speed. This process allows ships to efficiently travel at their design speed. However, it is useful to know how the propeller performs during off-design conditions. This is especially true for naval warships whose missions require them to perform at a wide range of spee...

  15. Classification of edge-transitive propeller graphs

    OpenAIRE

    Sterns, Matthew C.

    2015-01-01

    In this paper, we introduce a family of tetravalent graphs called propeller graphs, denoted by $Pr_{n}(b,c,d)$. We then produce three infinite subfamilies and one finite subfamily of arc-transitive propeller graphs, and show that all such graphs are necessarily members of one of these four subfamilies, up to isomorphism. We close the paper with questions for further investigation, as well as a few conjectures.

  16. Propeller-driven Outflows and Disk Oscillations

    OpenAIRE

    Romanova, M. M.; Ustyugova, G. V.; Koldoba, A. V.; Lovelace, R. V. E.

    2005-01-01

    We report the discovery of propeller-driven outflows in axisymmetric magnetohydrodynamic simulations of disk accretion to rapidly rotating magnetized stars. Matter outflows in a wide cone and is centrifugally ejected from the inner regions of the disk. Closer to the axis there is a strong, collimated, magnetically dominated outflow of energy and angular momentum carried by the open magnetic field lines from the star. The ``efficiency'' of the propeller may be very high in the respect that mos...

  17. Surge Instability on a Cavitating Propeller

    OpenAIRE

    Duttweiler, Mark E.; Brennen, Christopher E.

    2001-01-01

    This study details experiments investigating a previously unrecognized surge instability on a cavitating propeller in a water tunnel. The surge instability is furst explored through visual observation of the cavitation on the propeller blades and in the tip vortices. Similarities between the instability and previously documented cavitation phenomena are noted. Measurements of the radiated pressure are then obtained, and the acoustic signature of the instability is identified. The magnitud...

  18. Launching of Jets by Propeller Mechanism

    OpenAIRE

    Romanova, M. M.; Lovelace, R. V. E.; Ustyugova, G. V.; Koldoba, A. V.

    2009-01-01

    We carried out axisymmetric simulations of disk accretion to a rapidly rotating magnetized star in the "propeller" regime. Simulations show that propellers may be "weak" (with no outflows), and "strong" (with outflows). Investigation of the difference between these two regimes have shown that outflows appear only in the case where the "friction" between the disk and magnetosphere is sufficiently large, and when accreting matter flux is not very small. Matter outflows in a wide cone and is mag...

  19. Water Contaminant Mitigation in Ionic Liquid Propellant

    Science.gov (United States)

    Conroy, David; Ziemer, John

    2009-01-01

    Appropriate system and operational requirements are needed in order to ensure mission success without unnecessary cost. Purity requirements applied to thruster propellants may flow down to materials and operations as well as the propellant preparation itself. Colloid electrospray thrusters function by applying a large potential to a room temperature liquid propellant (such as an ionic liquid), inducing formation of a Taylor cone. Ions and droplets are ejected from the Taylor cone and accelerated through a strong electric field. Electrospray thrusters are highly efficient, precise, scaleable, and demonstrate low thrust noise. Ionic liquid propellants have excellent properties for use as electrospray propellants, but can be hampered by impurities, owing to their solvent capabilities. Of foremost concern is the water content, which can result from exposure to atmosphere. Even hydrophobic ionic liquids have been shown to absorb water from the air. In order to mitigate the risks of bubble formation in feed systems caused by water content of the ionic liquid propellant, physical properties of the ionic liquid EMI-Im are analyzed. The effects of surface tension, material wetting, physisorption, and geometric details of the flow manifold and electrospray emitters are explored. Results are compared to laboratory test data.

  20. Gravity Propelled Low Temperature Engine

    Directory of Open Access Journals (Sweden)

    Ikechi Ofong

    2014-10-01

    Full Text Available The aim of this study is to improve the performance of a gravity propelled low temperature engine. It consists of four concentric cylindrical tanks pairs, operating with two fluids, water and 1, 1, 1, 2-tetrafluoroethane (R-134a. The inner tank holds water which is responsible for producing rotation while the annulus between the concentric cylindrical tanks holds R-134a which vaporizes and produces the vapour pressure that moves water from lower to upper tank mates. Wheel rotation is achieved when the water mass falls by gravity from this height. The inner tanks of the tank pairs are linked by a pipe through which the working fluid is transferred. The entire assembly forms a power wheel of 1.5 m diameter. Heat energy is provided by warm water at 50°C contained in a trough located at the bottom of the wheel. Test results reveal that an average wheel speed of 2.5-3.0 rpm is possible, representing a performance improvement of over 500%. This corresponds to a possible power generation of 30-35 W. Thus power generation from this engine is possible and has the potential to serve as a good alternative power source in remote locations without grid connected electricity.

  1. Air lifted and propelled vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Jones, T.E.; Johnson, R.A.

    1987-02-17

    This patent describes a vehicle which rides on air cushion and which is propelled by air, comprising: upper deck means, having a bottom edge which defines the periphery of an area; a thin, flexible sheet located below the upper deck means, extending beneath the bottom edge and secured beneath the bottom edge for defining a plenum that is defined by and closed off by the upper deck means and the sheet. The deck means is shaped within the area defined by its bottom edge for causing the plenum to always be an open space and the upper deck means is rigid enough to maintain that open condition of the plenum; the sheet being secured in a manner permitting the sheet to pillow when air is pressurized in the plenum; and the sheet being perforated below the upper deck means for permitting exit of air from the plenum at a controllable rate through the perforations; the sheet having a large plurality of the perforations dispersed over most of its area below the upper deck means; each of the perforations being a hole.

  2. Propeller damaged and repair techniques at present; Hakuyo propeller sonsho oyobi sono hoshu gijutsu no genjo

    Energy Technology Data Exchange (ETDEWEB)

    Mianakata, J.; Okamoto, Y.; Takaishi, N.; Kawajiri, T

    1998-09-01

    The propeller of ship on sail wind the foreign bodies like floating bodies, submerging wood, chain and so forth and most of them suffer from bent and missing with cracks at blade extreme end to leading edges, and at trailing edges of propeller blade when propeller moves backward. When such kind of damage occurs, depending on the type of damage and place of damage of the blade, and when there is extreme increase in vibration due to the unbalance of Surface (Shaft) Force and Bearing Force, a case where sailing is continued by preliminary measures and permanent repair is carried out at the next dock or the case where the damaged propeller is repaired while in dock by the periodic test or intermediate test of vessel. In general restoration repair of damaged propeller blade is carried out, however, cracks may case at the welding repair portion while the propeller is in operation if the welding repair is carried out by unqualified repairer. In this report, from the propeller repair experience of about 20 years, outlines of damage propeller and its repairing technology are described. 5 refs., 8 figs., 3 tabs.

  3. Research into the propeller strut for high speed outboard motor

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Takashi; Sunayama, Yoshihiko

    1995-12-31

    For better performance of outboard motors for high speed craft, improvement in the performance of the propeller strut located ahead of the propeller is indispensable in addition to ameliorating the performance of the screw propeller itself. Thus, it is extremely important to reduce the drag of the propeller strut, which accounts for the predominant portion of the submerged parts of the motor and hull when the craft is running at high speed and to improve the propeller efficiency in the wake of the propeller strut. This paper, taking up two different shapes of the propeller strut, compares the performances of the propeller placed in the wake of the propeller strut in tank tests, and discusses the drag of the propeller strut. The two propeller strut shapes are that of a 70% scaled down model of the propeller strut Suzuki`s 200 PS outboard motor and its improved version. The propeller used in the experiment is one having super cavitating blades with the Pseudo-Kirchhoff nose, whose performance the authors have been analyzing systematically. Detailed comparison was further made of the drags of the differently shaped propeller struts by means of computational fluid dynamics.

  4. Thermal Vacuum Test Correlation of a Zero Propellant Load Case Thermal Capacitance Propellant Gauging Analytical Model

    Science.gov (United States)

    Mckim, Stephen A.

    2016-01-01

    This thesis describes the development and correlation of a thermal model that forms the foundation of a thermal capacitance spacecraft propellant load estimator. Specific details of creating the thermal model for the diaphragm propellant tank used on NASA's Magnetospheric Multiscale spacecraft using ANSYS and the correlation process implemented are presented. The thermal model was correlated to within plus or minus 3 degrees Celsius of the thermal vacuum test data, and was determined sufficient to make future propellant predictions on MMS. The model was also found to be relatively sensitive to uncertainties in applied heat flux and mass knowledge of the tank. More work is needed to improve temperature predictions in the upper hemisphere of the propellant tank where predictions were found to be 2 to 2.5 C lower than the test data. A road map for applying the model to predict propellant loads on the actual MMS spacecraft toward its end of life in 2017-2018 is also presented.

  5. IHI marine propeller design (present and future); Hakuyo propeller sekkei no genjo to tenbo

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, S.; Fujino, R.; Ishida, S. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1996-01-01

    State-of-the-art of IHI marine propeller design is presented in this paper, including a number of significant developments in marine propellers which have been appeared to meet the needs of the times. The increased demand for higher efficiency was motivated by the energy crisis of the 1970s, and resulted in our development of the Grim Vane Wheel (GVW) system and Contra-Rotating Propeller (CRP) systems in the 1980s. Present demand is for more research and development into propellers of reduced cavitation and increased efficiency. Furthermore, propeller design now requires consideration of correct matching with the hull, rudder and other appendages to solve these problems. The design concept was applied to a high speed car ferry cruising at 29.4 kt. Finally, some new research reflecting moving trends and future markets is described. 13 refs., 11 figs., 1 tab.

  6. Reduction in efficiency of propellers due to slipstream

    Science.gov (United States)

    Munk, Max M

    1923-01-01

    In the slipstream behind a propeller there is a considerable amount of kinetic energy which has been imparted to it by the engine without producing any corresponding propeller thrust. The increased absorption of power reduces the propeller efficiency. Attention has been previously directed to this question by Bendemann and Madelung and other writers. Their contribution serves to verify a simple method of calculating the reduction in the propeller efficiency due to the slip stream. That method of calculation is given here. Explanations and examples are given for as single propeller and for two propellers mounted in tandem.

  7. Prediction of Performance of a Cavitating Propeller in Oblique Inflow

    Science.gov (United States)

    Tian, Ye; Kinnas, Spyros A.

    2015-12-01

    A cavitating propeller subject to an oblique inflow in a cavitating tunnel is simulated using potential flow methods coupled with a Reynolds-averaged Navier-Stokes (RANS) solver. The propeller is mainly modelled using a panel method, while the inflow to the propeller is evaluated by coupling a Vortex-Lattice Method (VLM) with the RANS solver. The effects of the tunnel wall are incorporated into the calculated effective inflow to the propeller. The predicted propeller forces and cavity pattern are correlated with experiment. The fully wetted open water characteristics of the propeller predicted by the panel method are presented as well.

  8. In-Space Propellant Production Using Water

    Science.gov (United States)

    Notardonato, William; Johnson, Wesley; Swanger, Adam; McQuade, William

    2012-01-01

    A new era of space exploration is being planned. Manned exploration architectures under consideration require the long term storage of cryogenic propellants in space, and larger science mission directorate payloads can be delivered using cryogenic propulsion stages. Several architecture studies have shown that in-space cryogenic propulsion depots offer benefits including lower launch costs, smaller launch vehicles, and enhanced mission flexibility. NASA is currently planning a Cryogenic Propellant Storage and Transfer (CPST) technology demonstration mission that will use existing technology to demonstrate long duration storage, acquisition, mass gauging, and transfer of liquid hydrogen in low Earth orbit. This mission will demonstrate key technologies, but the CPST architecture is not designed for optimal mission operations for a true propellant depot. This paper will consider cryogenic propellant depots that are designed for operability. The operability principles considered are reusability, commonality, designing for the unique environment of space, and use of active control systems, both thermal and fluid. After considering these operability principles, a proposed depot architecture will be presented that uses water launch and on orbit electrolysis and liquefaction. This could serve as the first true space factory. Critical technologies needed for this depot architecture, including on orbit electrolysis, zero-g liquefaction and storage, rendezvous and docking, and propellant transfer, will be discussed and a developmental path forward will be presented. Finally, use of the depot to support the NASA Science Mission Directorate exploration goals will be presented.

  9. Wakes of idealized propeller shafts with sleeves

    Energy Technology Data Exchange (ETDEWEB)

    Hally, D. [Defence R and D Canada - Atlantic, Dartmouth, Nova Scotia (Canada)]. E-mail: david.hally@drdc-rddc.gc.ca

    2005-07-01

    The rotation of a bare propeller shaft on a twin screw ship can have a significant effect on the flow into the propeller plane, with consequent effects on the propeller efficiency and cavitation characteristics. TRANSOM, the DRDC Atlantic flow solver, was used to determine whether covering the shaft with a nonrotating sleeve along part of its length would improve the propeller inflow. Two sets of calculations were performed. In the first a semi-infinite cylindrical shaft protruded from a flat plate. The shaft was covered along part of its length by a zero thickness stationary sleeve. To gain an understanding of the effects of the diameter of the sleeve relative to the shaft, a second set of calculations was performed in which the diameter of the sleeve was larger than that of the shaft. To avoid complications in gridding this configuration, the flat plate was removed; the shaft was infinite in both directions with a change in radius and a change from non-rotating to rotating in the middle. These calculations suggest that a sleeve will reduce the wake fraction in the propeller disk by delaying the formation of a vortex that entrains velocity deficit from the hull boundary layer. The sleeve also keeps the entrained velocity deficit closer to the shaft where it is less likely to induce cavitation. As the mismatch in radii of the sleeve and shaft increases, the entrained velocity deficit increases, so thinner sleeves should be preferred. (author)

  10. Electrostatic Discharge testing of propellants and primers

    Energy Technology Data Exchange (ETDEWEB)

    Berry, R.B.

    1994-02-01

    This report presents the results of testing of selected propellants and primers to Electrostatic Discharge (ESD) characteristic of the human body. It describes the tests and the fixturing built to accommodate loose material (propellants) and the packed energetic material of the primer. The results indicate that all powders passed and some primers, especially the electric primers, failed to pass established requirements which delineate insensitive energetic components. This report details the testing of components and materials to four ESD environments (Standard ESD, Severe ESD, Modified Standard ESD, and Modified Severe ESD). The purpose of this study was to collect data based on the customer requirements as defined in the Sandia Environmental Safety & Health (ES&H) Manual, Chapter 9, and to define static sensitive and insensitive propellants and primers.

  11. Heterogeneous propellant internal ballistics: criticism and regeneration

    Science.gov (United States)

    Glick, R. L.

    2011-10-01

    Although heterogeneous propellant and its innately nondeterministic, chemically discrete morphology dominates applications, ballisticcharacterization deterministic time-mean burning rate and acoustic admittance measures' absence of explicit, nondeterministic information requires homogeneous propellant with a smooth, uniformly regressing burning surface: inadequate boundary conditions for heterogeneous propellant grained applications. The past age overcame this dichotomy with one-dimensional (1D) models and empirical knowledge from numerous, adequately supported motor developments and supplementary experiments. However, current cost and risk constraints inhibit this approach. Moreover, its fundamental science approach is more sensitive to incomplete boundary condition information (garbage-in still equals garbage-out) and more is expected. This work critiques this situation and sketches a path forward based on enhanced ballistic and motor characterizations in the workplace and approximate model and apparatus developments mentored by CSAR DNS capabilities (or equivalent).

  12. Propellant Grade Hydrazine in Mono/Bi-propellant Thrusters: Preparation and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    S. Krishnamachary

    2015-03-01

    Full Text Available Propellant grade hydrazine was prepared with 64 per cent yield and 95.5 per cent purity. Purity of the propellant grade hydrazine was determined using wet chemical, gas chromatographic (GC and eudiometric methods. It was observed that the compositions containing blends of hydrazine-methyl alcohol-ammonium nitrate and hydrazine-methyl alcohol-ammonium perchlorate were not found to be frozen even after cooling to -65 °C for 30 minutes. Mono and bi-propellant thrusters were designed and developed to demonstrate the performance of prepared propellant grade hydrazine as a promising rocket fuel. Five static tests with 22 N thruster and one static test with 1 N thruster were performed successfully in mono-propellant mode. The hurdles of chamber pressure oscillations were overcome by compact packing of the catalyst. The desired decomposition and chamber pressure were achieved. One static test was performed successfully with 60 N bi-propellant thruster. The desired chamber pressure and thrust were achieved. The combustion was smooth and C* achieved was higher than that of UH-25, N2O4 combination. The performance of prepared propellant grade hydrazine shows it as a promising rocket fuels.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.31-38, DOI:http://dx.doi.org/10.14429/dsj.65.7986

  13. CFD based propeller modelling and optimization

    OpenAIRE

    Greco, Luca; Testa, Claudio; Leone, Stefania; Salvatore, Francesco; Peri, Daniele; Mauro, Salvatore

    2012-01-01

    This report is written in fulfilment of deliverable D3.3 of the EU-FP7 project HyMAR. Aim of the project is to develop innovative hybrid drive train systems for small and medium size marine vehicles, by exploiting self-pitching propellers. In this context, the present report describes an automated optimal design procedure developed in the project and presents the results of applying this methodology to a practical self-pitching propeller design exercise. The proposed design procedure combines...

  14. Image domain propeller fast spin echo☆

    OpenAIRE

    Skare, Stefan; Holdsworth, Samantha J.; Lilja, Anders; Bammer, Roland

    2012-01-01

    A new pulse sequence for high-resolution T2-weighted (T2-w) imaging is proposed –image domain propeller fast spin echo (iProp-FSE). Similar to the T2-w PROPELLER sequence, iProp-FSE acquires data in a segmented fashion, as blades that are acquired in multiple TRs. However, the iProp-FSE blades are formed in the image domain instead of in the k-space domain. Each iProp-FSE blade resembles a single-shot fast spin echo (SSFSE) sequence with a very narrow phase-encoding field of view (FOV), after...

  15. Material Compatibility with Space Storable Propellants. Design Guidebook

    Science.gov (United States)

    Uney, P. E.; Fester, D. A.

    1972-01-01

    An important consideration in the design of spacecraft for interplanetary missions is the compatibility of storage materials with the propellants. Serious problems can arise because many propellants are either extremely reactive or subject to catalytic decomposition, making the selection of proper materials of construction for propellant containment and control a critical requirement for the long-life applications. To aid in selecting materials and designing and evaluating various propulsion subsystems, available information on the compatibility of spacecraft materials with propellants of interest was compiled from literature searches and personal contacts. The compatibility of both metals and nonmetals with hydrazine, monomethyl hydrazine, nitrated hydrazine, and diborance fuels and nitrogen tetroxide, fluorine, oxygen difluoride, and Flox oxidizers was surveyed. These fuels and oxidizers encompass the wide variety of problems encountered in propellant storage. As such, they present worst case situations of the propellant affecting the material and the material affecting the propellant. This includes material attack, propellant decomposition, and the formation of clogging materials.

  16. Innovative Swirl Injector for LOX and Hydrocarbon Propellants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Gases trapped in the propellant feed lines of space-based rocket engines due to cryogenic propellant boil-off or pressurant ingestion can result in poor combustion...

  17. A review of propeller modelling techniques based on Euler methods

    OpenAIRE

    Zondervan, G.J.D.

    1995-01-01

    Future generation civil aircraft will be powered by new, highly efficient propeller propulsion systems. New, advanced design tools like Euler methods will be needed in the design process of these aircraft. This report describes the application of Euler methods to the modelling of flowfields generated by propellers. An introduction is given in the general layout of propellers and the propeller slipstream. It is argued that Euler methods can treat a wider range of flow conditions than the class...

  18. Developments in modelling ship rudder-propeller interaction

    OpenAIRE

    Molland, A.F.; Turnock, S.R.

    1994-01-01

    A review is made of the physics of the flow between a rudder and propeller and the parameters governing their interaction. Recent developments in predicting rudder forces and rudder-propeller interaction are described. These entail treating the rudder-propeller combination as the overall manoeuvring and propulsion device. Reference is made to on-going research at the University of Southampton which has included wind tunnel experimental investigations of the basic rudder-propeller interaction ...

  19. Numerical Modelling of Regenerative Liquid Propellant Guns with Annular Piston

    OpenAIRE

    K. J. Daniel; D. K. Kharat; K.R. Rao; Shah, S.T.; S. C. Mitra

    1997-01-01

    The development of regenerative liquid propellant guns (RLPGs) needs due consideration of numerous interdependent parameters that affect its performance. To help in this task, computer simulation was undertaken to predict internal ballistics of a conceptual liquid propellant gun. The expected pressure and other important parameters are documented which serve as an aid to the hardware, design of the regenerative liquid propellant guns.

  20. 14 CFR 35.23 - Propeller control system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller control system. 35.23 Section 35.23 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Design and Construction § 35.23 Propeller control system. The requirements of this section apply to any system...

  1. 14 CFR 25.1027 - Propeller feathering system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller feathering system. 25.1027 Section 25.1027 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Oil System § 25.1027 Propeller feathering system. (a) If the propeller...

  2. 14 CFR 25.33 - Propeller speed and pitch limits.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch limits. 25.33 Section 25.33 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight General § 25.33 Propeller speed and pitch limits. (a) The propeller speed and...

  3. 14 CFR 25.875 - Reinforcement near propellers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Reinforcement near propellers. 25.875 Section 25.875 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION....875 Reinforcement near propellers. (a) Each part of the airplane near the propeller tips must...

  4. Minuteman 3: Stage 3 propellant fire characterization

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, J C

    1994-06-20

    We have completed an experimental program to diagnose and characterize the thermal environment of a solid rocket propellant fire burning in ambient atmospheric conditions. This work has been conducted as part of the Defense Nuclear Agency`s probabilistic risk assessment (PRA) of the Minuteman III (MMIII) weapon system. The goals of this study are two-fold; (1) to provide a description of a propellant fire in sufficient detail so as to allow system response models to predict the outcome of various hypothetical accident, scenarios and, (2) to identify diagnostics that could be used in a large-scale test fire of MMIII stage 3 motor. The study has been performed burning SRAM II and MMIII stage 3 propellant (ANB-3066), in chimneys ranging in size from 18 cm to 53 cm (twenty-one inches) in diameter. Several methods have been used to determine and confirm temperature measurements including thermometry, radiometry, and ultrasonic thermal sensing. Temperature profiles with peaks in excess of 2300{degree} C have been measured. Temperature measurements have been used in conjunction with inverse modeling to determine heat flux characteristics. The regression rate for ANB-3066 (under ambient conditions) has also been determined. Finally, at a very cursory level, we have studied the characteristics of aluminum oxide deposits as well as some materials responses to these fires. We have also addressed the initial efforts on development of diagnostics, problems encountered in controlling the burning of propellants, in taking radiometric measurements, and the survivability of materials in the fire.

  5. Bulkhead rupture disc for solid propellant missiles

    Energy Technology Data Exchange (ETDEWEB)

    Hibler, D.R. Sr.; Sigle, S.P. Jr.

    1988-04-19

    A missile bulkhead rupture disc assembly for disposition between a first stage of propellant and a second stage of propellant and for enabling release of the second stage of propellant subsequent to release of the first stage of propellant is described comprising: a generally circular element comprised of a frangible material and having a first burst pattern with a line of weakness completely circumscribing a central portion of the element. The central portion of the element having structure defines an aperture. The element has a second burst pattern comprising lines of weakness each extending in a substantially radial direction outwardly from the line of weakness of the first burst pattern. Each adjacent pair of the lines of weakness of the second burst pattern is spaced from each other and defines generally sector-shaped segments of the elements. The frangible material of the element has a tensile strength of a certain, first value in the vicinity of the line of weakness of the first burst pattern, and the frangible material of the element has a tensile strength in the vicinity of the lines of weakness of the second burst pattern of a second value which is higher than the first certain value.

  6. Atmospheric surveillance self-propelling device

    International Nuclear Information System (INIS)

    The atmospheric surveillance self-propelling device of the Saclay Nuclear Research Center can, by its conception (autonomy, rapid put into service, multiplicity of sampling and measurements), be used for all kind of measuring campains: pollution radioactive or not, routine or accidental situation, technical and logistic support and as a coordination or investigation vehicle

  7. Tumbleweed: Wind-Propelled Measurements for Mars

    Science.gov (United States)

    Kuhlman, K. R.; Behar, A.; Jones, J.; Coleman, M.; Boston, P.; McKay, C. P.; Rothschild, L. J.; Buehler, M. G.; Northup, D.; Choi, D. S.

    2012-06-01

    Tumbleweed is a wind-propelled, long-range, autonomous vehicle based on well-developed airbag technology which will survey Mars for variations in habitability using the Mars exploration paradigm, “Follow the Water” or to survey for in-situ resources.

  8. Numerical simulations of a propeller wake impacting

    Energy Technology Data Exchange (ETDEWEB)

    Hi, M.; Veitch, B.; Bose, N. [Memorial Univ. of Newfoundland, Faculty of Engineering and Applied Science, St. John' s, Newfoundland (Canada)]. E-mail: moqinhe@engr.mun.ca; Bruce, C.; Liu, P. [National Research Council Canada, Inst. for Ocean Technology, St. John' s, Newfoundland (Canada)

    2005-07-01

    This paper introduces a newly developed Wake Impingement Model (WIM) that aims to simulate of the dynamic loads induced by a three dimensional, unsteady, and strong vortical propeller wake. Simulations of loads on an ice class, tractor type podded propeller in straight ahead motion are presented consisting of mean loads on the propeller and side force on the pod and strut. The side force fluctuations for three different advance coefficients have also been predicted. These simulations were carried out by using a panel code, PROPELLA, with or without WIM. Simulated results were compared with and without WIM and with experimental data. The comparison of the propeller open water characteristics of two simulated results shown there is almost no difference between predictions with and without WIM. It was found by comparing with experimental data that the simulations of the side force on the pod and strut with WIM successfully captured the fluctuation which was dominated by the component at the blade passing frequency, although this was at a reduced level compared with the measurements. (author)

  9. Acoustic source strength of propeller cavitation

    NARCIS (Netherlands)

    Bruijn, A. de

    1979-01-01

    The acoustic source strength i.e. the volume velocity of propeller cavitation for six single-screw ships are presented. Plotting the data in the form of dimensionleee volume velocity and as a function of the cavitation number based on the rotation speed and the immersion depth, a certain differentia

  10. Image based measurement techniques for aircraft propeller flow diagnostics: Propeller slipstream investigations at high-lift conditions and thrust reverse

    OpenAIRE

    Roosenboom, E.W.M.

    2011-01-01

    The aim of the thesis is to measure the propeller slipstream properties (velocity and vorticity) and to assess the unsteady and instantaneous behavior of the propeller flow field at high disk loadings, zero thrust and thrust reverse using the image based measurement techniques. Along with its implementation of the techniques in industrial facilities particular propeller phenomena are addressed, such as the propeller slipstream behavior at varying angles of attack, and its interaction with the...

  11. The hard start phenomena in hypergolic engines. Volume 2: Combustion characteristics of propellants and propellant combinations

    Science.gov (United States)

    Miron, Y.; Perlee, H. E.

    1974-01-01

    The combustion characteristics of hypergolic propellants are described. A research project was conducted to determine if the reaction control system engine propellants on Apollo spacecraft undergo explosive reaction when subjected to conditions present in the engine at the time of ignition. Combustion characteristics pertinent to the hard-start phenomenon are considered. The thermal stability of frozen mixtures of hydrazine-based fuels with nitrogen tetroxide was analyzed. Results of the tests are presented in the form of tables and graphs.

  12. Ion engine propelled Earth-Mars cycler with nuclear thermal propelled transfer vehicle, volume 2

    Science.gov (United States)

    Meyer, Rudolf X.; Baker, Myles; Melko, Joseph

    1994-01-01

    The goal of this project was to perform a preliminary design of a long term, reusable transportation system between earth and Mars which would be capable of providing both artificial gravity and shelter from solar flare radiation. The heart of this system was assumed to be a Cycler spacecraft propelled by an ion propulsion system. The crew transfer vehicle was designed to be propelled by a nuclear-thermal propulsion system. Several Mars transportation system architectures and their associated space vehicles were designed.

  13. The design of propeller and propeller boss cap fins (PBCF) by an integrative method

    Institute of Scientific and Technical Information of China (English)

    MA Cheng; CAI Hao-peng; QIAN Zheng-fang; CHEN Ke

    2014-01-01

    Generally, after a marine propeller design, the propeller boss cap fins (PBCF) design concerns with an optimal selection of model test results, without a due consideration of the interaction between the PBCF and the propeller. In this paper, the PBCF and the propeller are considered as a whole system with their design as an integrative process, in which the concept of the increased loading in the blade root is incorporated. The load distribution on the blade becomes well-proportioned due to the increased loading in the blade root, and it is advantageous to the reduction of the vibratory force and the blade tip vortex. The blade root area is stronger in withstanding forces, and is not easy to be vibrated, therefore, the increased loading there is beneficial to the noise reduction. The disadvantage of the increased loading in the blade root is the generation of the hub vortex behind the boss cap, but the hub vortex can be broken up by the energy saving hydrodynamic mechanism of the PBCF. The integrative design method introduced in this paper can provide a higher efficiency for propellers under the same design conditions. In this paper, an integrative propeller and PBCF design method including the theoretical design and the numerical optimization design is proposed, based on the potential flow theory, the CFD tools, the improved particle swarm optimization algorithm, and the model tests. A propeller with the PBCF is designed based on the method of integrated increased loading in the blade root for a cargo vessel in this paper. The cavitation tunnel model test results show that the propeller and the PBCF thus designed enjoys a higher efficiency, and the design method is effective, reliable and practical.

  14. Space Transportation Infrastructure Supported By Propellant Depots

    Science.gov (United States)

    Smitherman, David; Woodcock, Gordon

    2012-01-01

    A space transportation infrastructure is described that utilizes propellant depot servicing platforms to support all foreseeable missions in the Earth-Moon vicinity and deep space out to Mars. The infrastructure utilizes current expendable launch vehicle (ELV) systems such as the Delta IV Heavy, Atlas V, and Falcon 9, for all crew, cargo, and propellant launches to orbit. Propellant launches are made to Low-Earth-Orbit (LEO) Depot and an Earth-Moon Lagrange Point 1 (L1) Depot to support a new reusable in-space transportation vehicles. The LEO Depot supports missions to Geosynchronous Earth Orbit (GEO) for satellite servicing and to L1 for L1 Depot missions. The L1 Depot supports Lunar, Earth-Sun L2 (ESL2), Asteroid and Mars Missions. New vehicle design concepts are presented that can be launched on current 5 meter diameter ELV systems. These new reusable vehicle concepts include a Crew Transfer Vehicle (CTV) for crew transportation between the LEO Depot, L1 Depot and missions beyond L1; a new reusable lunar lander for crew transportation between the L1 Depot and the lunar surface; and Mars orbital Depot are based on International Space Station (ISS) heritage hardware. Data provided includes the number of launches required for each mission utilizing current ELV systems (Delta IV Heavy or equivalent) and the approximate vehicle masses and propellant requirements. Also included is a discussion on affordability with ideas on technologies that could reduce the number of launches required and thoughts on how this infrastructure include competitive bidding for ELV flights and propellant services, developments of new reusable in-space vehicles and development of a multiuse infrastructure that can support many government and commercial missions simultaneously.

  15. BETA-S, Multi-Group Beta-Ray Spectra

    International Nuclear Information System (INIS)

    1 - Description of program or function: BETA-S calculates beta-decay source terms and energy spectra in multigroup format for time-dependent radionuclide inventories of actinides, fission products, and activation products. Multigroup spectra may be calculated in any arbitrary energy-group structure. The code also calculates the total beta energy release rate from the sum of the average beta-ray energies as determined from the spectral distributions. BETA-S also provides users with an option to determine principal beta-decaying radionuclides contributing to each energy group. The CCC-545/SCALE 4.3 (or SCALE4.2) code system must be installed on the computer before installing BETA-S, which requires the SCALE subroutine library and nuclide-inventory generation from the ORIGEN-S code. 2 - Methods:Well-established models for beta-energy distributions are used to explicitly represent allowed, and 1., 2. - and 3. -forbidden transition types. Forbidden non-unique transitions are assumed to have a spectral shape of allowed transitions. The multigroup energy spectra are calculated by numerically integrating the energy distribution functions using an adaptive Simpson's Rule algorithm. Nuclide inventories are obtained from a binary interface produced by the ORIGEN-S code. BETA-S calculates the spectra for all isotopes on the binary interface that have associated beta-decay transition data in the ENSDF-95 library, developed for the BETA-S code. This library was generated from ENSDF data and contains 715 materials, representing approximately 8500 individual beta transition branches. 3 - Restrictions on the complexity of the problem: The algorithms do not treat positron decay transitions or internal conversion electrons. The neglect of positron transitions in inconsequential for most applications involving aggregate fission products, since most of the decay modes are via electrons. The neglect of internal conversion electrons may impact on the accuracy of the spectrum in the low

  16. Laser Propulsion with Liquid Propellants Part I: an Overview

    International Nuclear Information System (INIS)

    Despite years of research, laser propulsion on liquid propellants has yet to achieve specific impulses greater than tens of seconds. It is well established that liquids, when used as propellants, can provide coupling coefficient (Cm) on the order of 100-1000 dyne/W. However, the specific impulse (Isp) has proven to be significantly inferior to that for solid propellants. This paper will examine the various laser propulsion schemes based on ablation of liquid propellants and intended primarily for space applications. The principal shortcomings associated with liquid propellants will be outlined

  17. Research on On-Orbit Storage Scheme of Cryogenic Propellant

    Science.gov (United States)

    Xiaolin, Dong

    2016-07-01

    For manned deep space explorations as lunar and mars exploration,the cryogenic propellant is required to be on-orbit for a long time, from several days to years. However, because of the low boiling point of cryogenic propellant, it is easy to be boiled off. We should pay attention to the heat transfer path and influencing factors of cryogenic propellant on-orbit storage. This Paper proposed a scheme of cryogenic propellant on-orbit storage and gave an analysis of the key technologies, in order to promote the on-orbit application of cryogenic propellant.

  18. Computation of Blast Pressures foam Propellant for Compaction of Soil

    Directory of Open Access Journals (Sweden)

    K. B. Agarwal

    1974-01-01

    Full Text Available The knowledge of blast pressure characteristics is a pre-requisite for a suitable application of foam propellant to emergency military construction such as compacting of the soil from an aircraft using the foam propellant. The foam propellant considered here is a combination of hydrazine and ammonium perchlorate. The blast pressure is found to be a function of the quantity of foam propellant used and the distance of the observation point. This paper attempts to compute the blast pressure versus time characteristics of a foam propellant strip.

  19. Analisa Aliran Hub Cap Propeller Terhadap Pengaruh Nozzle Ring

    Directory of Open Access Journals (Sweden)

    Wicaksono Wicaksono

    2014-03-01

    Full Text Available Propeller mempunyai peranan yang penting,dimana alat tersebut yang sering digunakan untuk mengerakan kapal,propeller sendiri dapat mengubah gaya gerak (putar menjadi gaya dorong,berdasarkan studi lebih lanjut dalam penelitian ini,banyak ditemukan tipe propeller yang sudah dimodifikasi untuk memdapatkan performa yang lebih baik,untuk meningkatan efisiensi.tujuan dari tugas akhir ini adalah menghybrid nozzle ring dengan hub cap propeller yang mana dapat mempengaruhi besar dari thrust,torque,dan juga efisiensi yang maksimal dengan pendekatan CFD   (Computational,Fluid,Dynamic,variabel yang divariasikan  adlah sudu ducted dengan hub cap propeller.

  20. Performance of a capillary propellant management device with hydrazine

    Science.gov (United States)

    Tegart, J. R.

    1979-01-01

    The propellant management device that was successfully used in the Viking Orbiter spacecraft was selected for the main propulsion system of the Teleoperator Retrieval System (TRS). Due to differences in the missions and different propellants, the operation of this sheet metal vane device required reverification for the TRS application. An analytical investigation was performed considering the adverse acceleration environment and the high contract angle of the hydrazine propellant. Drop tower tests demonstrated that the device would provide propellant acquisition while the TRS was docked with Skylab, but its operation would have to be supplemented through propellant settling when free-flying.

  1. Space Transportation Infrastructure Supported By Propellant Depots

    Science.gov (United States)

    Smitherman, David; Woodcock, Gordon

    2011-01-01

    A space transportation infrastructure is described that utilizes propellant depots to support all foreseeable missions in the Earth-Moon vicinity and deep space out to Mars. The infrastructure utilizes current expendable launch vehicles such as the Delta IV Heavy, Atlas V, and Falcon 9, for all crew, cargo, and propellant launches to orbit. Propellant launches are made to a Low-Earth-Orbit (LEO) Depot and an Earth-Moon Lagrange Point 1 (L1) Depot to support new reusable in-space transportation vehicles. The LEO Depot supports missions to Geosynchronous Earth Orbit (GEO) for satellite servicing, and to L1 for L1 Depot missions. The L1 Depot supports Lunar, Earth-Sun L2 (ESL2), Asteroid, and Mars missions. A Mars Orbital Depot is also described to support ongoing Mars missions. New concepts for vehicle designs are presented that can be launched on current 5-meter diameter expendable launch vehicles. These new reusable vehicle concepts include a LEO Depot, L1 Depot, and Mars Orbital Depot based on International Space Station (ISS) heritage hardware. The high-energy depots at L1 and Mars orbit are compatible with, but do not require, electric propulsion tug use for propellant and/or cargo delivery. New reusable in-space crew transportation vehicles include a Crew Transfer Vehicle (CTV) for crew transportation between the LEO Depot and the L1 Depot, a new reusable Lunar Lander for crew transportation between the L1 Depot and the lunar surface, and a Deep Space Habitat (DSH) to support crew missions from the L1 Depot to ESL2, Asteroid, and Mars destinations. A 6 meter diameter Mars lander concept is presented that can be launched without a fairing based on the Delta IV heavy Payload Planners Guide, which indicates feasibility of a 6.5 meter fairing. This lander would evolve to re-usable operations when propellant production is established on Mars. Figure 1 provides a summary of the possible missions this infrastructure can support. Summary mission profiles are presented

  2. Solid propellant extinction by laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Novozhilov, B.V. [Russian Academy of Science, Moscow (Russian Federation). Inst. of Chemical Physics; Zanotti, C.; Giuliani, P. [Istituto per la Tecnologia dei Materiali e dei Processi Energetici TeMPE - C.N.R., Milano (Italy)

    2000-12-01

    The possibility to generate a combustion transient of a composite AP.HTPB/86.14 propellant, burning under steady state conditions, was experimentally demonstrated by using a CO{sub 2} laser energy pulse. The experimental results point out that the burning propellant behavior can be defined by the curves separating, for every operating pressure, the continuous burning from the extinction solutions. In this paper, a simplified theoretical approach gives a phenomenological explanation of the energy pulse effect on the combustion process and the consequent burning propellant response after the deradiation transient. In the framework of this study the extinction condition is formulated in terms of the minimum temperature that causes the burning propellant to quench at the Pressure Deflagration Limit. The proposed theoretical work is aimed, first of all, to determine the critical radiant flux values, for different operating pressures, below which the burning propellant extinction is never achieved even if the laser pulse duration tends to infinity. Then, the extinction boundaries are defined choosing two different approximate approaches that take into account the ratio between the condensed phase relaxation time and the radiant energy pulse duration. Two limit cases, defined as slow/fast interaction of the radiant energy with the combustion process, can be used to describe the burning propellant extinction phenomena, and the results of this work indicate that the general trend of the computed boundary limits reproduces the experimental data. (orig.) [German] Mit einem CO{sub 2}-Laser wurde die Moeglichkeit demonstriert, einen Uebergangszustand der Verbrennung eines Komposit-Treibstoffes AP.HTPB/86.14 zu erzeugen, der unter stationaeren Bedingungen brannte. Die experimentellen Ergebnisse zeigen auf, dass das Verbrennungsverhalten durch die Kurven bestimmt werden kann, die fuer jeden Arbeitsdruck die kontinuierlichen Verbrennungsloesungen von den Ausloeschloesung trennen

  3. Parametric Erosion Investigation: Propellant Adiabatic Flame Temperature

    Directory of Open Access Journals (Sweden)

    P. J. Conroy

    2002-01-01

    Full Text Available The influence of quasi-independent parameters and their potential influence on erosion in guns have been investigated. Specifically, the effects of flame temperature and the effect of assuming that the Lewis number (ratio of mass-to-heat transport to the surface, Le = 1, has been examined. The adiabatic flame temperature for a propellant was reduced by the addition of a diluent from a high temperature of 3843 K (similar to that of M9 down to 3004 K, which is near the value for M30A1 propellant. Mass fractions of critical species at the surface with and without the assumption of Le = 1 are presented, demonstrating that certain species preferentially reach the surface providing varied conditions for the surface reactions. The results for gun tube bore surface regression qualitatively agree with previous studies and with current experimental data.

  4. High Impetus Cool Burning Gun Propellants

    Directory of Open Access Journals (Sweden)

    R.S. Dames

    2000-07-01

    Full Text Available This study explores the possibility of reducing the flame temperature (Tf without decrease in impetus of RDX-NC matrix-based high energy gun propellants by partial replacement of RDX with triaminoguanidine nitrate (TAGN. Compositions containing TAGN as an energetic oxidiser with varying percentage of RDX have been formulated. Glycidyl azide polymer was incorporated as an energetic plasticiser to achieve the higher level of impetus. Performance in terms of ballistic parameters (theoretical/experimental sensitivity, thermal characteristics, stability and mechanical properties was evaluated and compared with the basic composition containing RDX as a single oxidiser. Experimental data indicates that the partial replacement of RDX by TAGN in gun propellant compositions decreases Tf significantly with only marginal decrease in impetus. "

  5. Rocket Propellants Engine Design/Operations/Validation

    Science.gov (United States)

    Monk, Jan C.

    2002-01-01

    Lockheed Martin Astronautics Operations (LMA) was competitively awarded a contract May 21, 2001 for next generation launch system architecture definition and technology maturation. The Second Generation Launch Vehicle Program objectives include reducing the technical and programmatic risk of proceeding to full scale development of the system by establishing requirements for the next generation launch system and maturing critical technologies needed by the system. LMA will conduct analyses and trades to optimize the architecture ETO elements including configuration, conceptual designs, and preliminary operations definition. To fully understand the engine and propellant trades were conducted by LMA to yield the optimized architecture system from the operability, reliability, safety, and cost perspectives. A government/industry team addressed the required trade studies, the parameters and weighting factors, and the most critical trades were addressed. This report summarizes the participation of JCM Consulting, Inc. in the propellant trade study.

  6. Self-Propelled Rods near Surfaces

    CERN Document Server

    Elgeti, Jens

    2009-01-01

    We study the behavior of self-propelled nano- and micro-rods in three dimensions, confined between two parallel walls, by simulations and scaling arguments. Our simulations include thermal fluctuations and hydrodynamic interactions, which are both relevant for the dynamical behavior at nano- to micrometer length scales. In order to investigate the importance hydrodynamic interactions, we also perform Brownian-dynamics-like simulations. In both cases, we find that self-propelled rods display a strong surface excess in confined geometries. An analogy with semi-flexible polymers is employed to derive scaling laws for the dependence on the wall distance, the rod length, and the propulsive force. The simulation data confirm the scaling predictions.

  7. Propellant material compatibility program and results

    Science.gov (United States)

    Toth, L. R.; Cannon, W. A.; Coulbert, C. D.; Long, H. R.

    1976-01-01

    The effects of long-term (up to 10 years) contact of inert materials with earth-storable propellants were studied for the purpose of designing chemical propulsion system components that can be used for current as well as future planetary spacecraft. The primary experimental work, and results to date are reported. Investigations include the following propellants: hydrazine, hydrazine-hydrazine nitrate blends, monomethyl-hydrazine, and nitrogen tetroxide. Materials include: aluminum alloys, corrosion-resistant steels, and titanium alloys. More than 700 test specimen capsules were placed in long-term storage testing at 43 C in the special material compatibility facility. Material ratings relative to the 10-year requirement have been assigned.

  8. Cryogenic Propellant Feed System Analytical Tool Development

    Science.gov (United States)

    Lusby, Brian S.; Miranda, Bruno M.; Collins, Jacob A.

    2011-01-01

    The Propulsion Systems Branch at NASA s Lyndon B. Johnson Space Center (JSC) has developed a parametric analytical tool to address the need to rapidly predict heat leak into propellant distribution lines based on insulation type, installation technique, line supports, penetrations, and instrumentation. The Propellant Feed System Analytical Tool (PFSAT) will also determine the optimum orifice diameter for an optional thermodynamic vent system (TVS) to counteract heat leak into the feed line and ensure temperature constraints at the end of the feed line are met. PFSAT was developed primarily using Fortran 90 code because of its number crunching power and the capability to directly access real fluid property subroutines in the Reference Fluid Thermodynamic and Transport Properties (REFPROP) Database developed by NIST. A Microsoft Excel front end user interface was implemented to provide convenient portability of PFSAT among a wide variety of potential users and its ability to utilize a user-friendly graphical user interface (GUI) developed in Visual Basic for Applications (VBA). The focus of PFSAT is on-orbit reaction control systems and orbital maneuvering systems, but it may be used to predict heat leak into ground-based transfer lines as well. PFSAT is expected to be used for rapid initial design of cryogenic propellant distribution lines and thermodynamic vent systems. Once validated, PFSAT will support concept trades for a variety of cryogenic fluid transfer systems on spacecraft, including planetary landers, transfer vehicles, and propellant depots, as well as surface-based transfer systems. The details of the development of PFSAT, its user interface, and the program structure will be presented.

  9. Self-propelled film-boiling liquids

    CERN Document Server

    Linke, H; Melling, L D; Taormina, M J; Francis, M J; Dow-Hygelund, C C; Narayanan, V K; Taylor, R P; Stout, A

    2005-01-01

    We report that liquids perform self-propelled motion when they are placed in contact with hot surfaces with asymmetric (ratchet-like) topology. The pumping effect is observed when the liquid is in the film-boiling regime, for many liquids and over a wide temperature range. We propose that liquid motion is driven by a viscous force exerted by vapor flow between the solid and the liquid.

  10. Soft deformable self-propelled particles

    OpenAIRE

    Menzel, Andreas M.; Ohta, Takao

    2012-01-01

    In this work we investigate the collective behavior of self-propelled particles that deform due to local pairwise interactions. We demonstrate that this deformation alone can induce alignment of the velocity vectors. The onset of collective motion is analyzed. Applying a Gaussian-core repulsion between the particles, we find a transition to disordered non-collective motion under compression. We here explain that this reflects the reentrant fluid behavior of the general Gaussian-core model now...

  11. Exploratory experimental investigation of a wave propeller

    OpenAIRE

    Dane, Carl W.

    1992-01-01

    Approved for public release; distribution is unlimited A low-speed wind tunnel investigation was conducted to determine if a small secondary airfoil or wave propeller, oscillating in a rotary plunging motion, could significantly affect the airflow over a lifting airfoil surface to delay the onset of stall. The lifting airfoil shape was a NACA 66(215)-216, chosen for its chordwise pressure port instrumentation. Testing consisted of measuring the pressure distribution of the NACA 66(215)-2...

  12. Energy production with a tubular propeller turbine

    OpenAIRE

    Almeida Samora, Irene; Hasmatuchi, Vlad; Münch-Alligné, C.; Franca, Mário J.; Schleiss, Anton; Helena M. Ramos

    2016-01-01

    Micro-hydropower is a way of improving the energetic efficiency of existent water systems. In the particular case of drinking water systems, several studies have showed that pressure reducing valves can be by-passed with turbines in order to recover the dissipated hydraulic energy to produce electricity. As conventional turbines are not always cost-effective for power under 20 kW, a new energy converter is studied. A five blade tubular propeller (5BTP), assessed through laboratorial tests on ...

  13. Propeller outflows from an MRI disc

    OpenAIRE

    Lii, Patrick S.; Romanova, Marina M.; Ustyugova, Galina V.; Koldoba, Alexander V.; Lovelace, Richard V. E.

    2013-01-01

    We present the results of axisymmetric simulations of MRI-driven accretion onto a rapidly rotating, magnetized star accreting in the propeller regime. The stellar magnetosphere corotates with the star, forming a centrifugal barrier at the disc-magnetosphere boundary which inhibits matter accretion onto the star. Instead, the disc matter accumulates at the disc-magnetosphere interface and slowly diffuses into the inner magnetosphere where it picks up angular momentum and is quickly ejected fro...

  14. A propeller-like uranyl metallomesogen

    OpenAIRE

    Cardinaels, Thomas; Ramaekers, Jan; Guillon, Daniel; Donnio, Bertrand; Binnemans, Koen

    2005-01-01

    Uranyl triflate forms with three imidazo[4,5-f]-1,10-phenanthroline ligands a propeller-like complex that exhibits a hexagonal columnar phase. The ligand is not liquid-crystalline, but a mesophase is induced upon complex formation with the uranyl salt. The thermal behavior has been investigated by polarizing optical microscopy and by high-temperature X-ray diffraction. A model of the stacking of the molecules in the mesophase is proposed.

  15. Ship model propeller manufacturing by using RPT

    OpenAIRE

    Bazzi, Tomaso; Benedetti, Lanfranco

    2009-01-01

    Manufacturing process of ship model components (i.e. rudders, propellers, fins, brackets, etc.), can be a time consuming and expensive procedure. For these reasons in the last 10 years, the research community in collaboration with the industries has developed new manufacturing techniques aimed at reducing the prototyping cost and provide rapidly models ready to be tested; moreover, a significant reduction of the necessary surface treatments and hand finishing has been achieved. In the present...

  16. Application of an Active Foil Propeller

    OpenAIRE

    Borgen, Christian Thomas

    2010-01-01

    In this master thesis the author has investigated the potential benefits from an active foil propeller. Foils are mounted on the hull and take advantage of the heaving and pitching motion of the vessel travelling and produce thrust, similarly to the tail find of aquatic mammals. Active foil means that the angle of the foil has been controlled to constantly maximise the thrust.The author has investigated the potential fuel savings for three vessels, an offshore supply vessel, a coastal tanker ...

  17. Evolution der β-Propeller Proteine

    OpenAIRE

    Chaudhuri, Indronil

    2008-01-01

    Die β-Propeller bilden eine große Gruppe von Proteinen, die aus strukturell repetitiven Einheiten, den Propellerblättern aufgebaut sind. Bioinformatische Analysen der Propellerproteine weisen auf einen Ursprung aus einer gemeinsamen ancestralen Form hin. Dabei sind zwei evolutionäre Szenarios für die Entstehung der Propellerfaltung denkbar, die Amplifikation aus einem einzelnen Blatt und die Oligomerisierung aus größeren Fragmenten. Im Labor wurde die strukturelle Wiederholungseinheit verwend...

  18. Control of Propeller Cavitation in Operational Conditions

    OpenAIRE

    Vrijdag, A.

    2009-01-01

    Off design conditions can have a severe impact on ship propulsion system behaviour. Resistance increase for instance leads to a higher engine loading, and can also easily lead to a decrease of cavitation inception speed with respect to calm water conditions. Wakefield variations due to ship motions, waves and manoeuvres also have effect on engine loading and on propeller cavitation. This dissertation discusses the model based development of a propulsion control system aiming at increased cavi...

  19. Launching of Jets by Propeller Mechanism

    CERN Document Server

    Romanova, M M; Ustyugova, G V; Koldoba, A V

    2009-01-01

    We carried out axisymmetric simulations of disk accretion to a rapidly rotating magnetized star in the "propeller" regime. Simulations show that propellers may be "weak" (with no outflows), and "strong" (with outflows). Investigation of the difference between these two regimes have shown that outflows appear only in the case where the "friction" between the disk and magnetosphere is sufficiently large, and when accreting matter flux is not very small. Matter outflows in a wide cone and is magneto-centrifugally ejected from the inner regions of the disk. Closer to the axis there is a strong, collimated, magnetically dominated outflow of energy and angular momentum carried by the open magnetic field lines from the star. The "efficiency" of the propeller may be very high in the respect that most of the incoming disk matter is expelled from the system in winds. The star spins-down rapidly due to the magnetic interaction with the disk through closed field lines and with corona through open field lines. This mechan...

  20. LRP4 third β-propeller domain mutations cause novel congenital myasthenia by compromising agrin-mediated MuSK signaling in a position-specific manner

    Science.gov (United States)

    Ohkawara, Bisei; Cabrera-Serrano, Macarena; Nakata, Tomohiko; Milone, Margherita; Asai, Nobuyuki; Ito, Kenyu; Ito, Mikako; Masuda, Akio; Ito, Yasutomo; Engel, Andrew G.; Ohno, Kinji

    2014-01-01

    Congenital myasthenic syndromes (CMS) are heterogeneous disorders in which the safety margin of neuromuscular transmission is compromised by one or more specific mechanisms. Using Sanger and exome sequencing in a CMS patient, we identified two heteroallelic mutations, p.Glu1233Lys and p.Arg1277His, in LRP4 coding for the postsynaptic low-density lipoprotein receptor-related protein 4. LRP4, expressed on the surface of the postsynaptic membrane of the neuromuscular junction, is a receptor for neurally secreted agrin, and LRP4 bound by agrin activates MuSK. Activated MuSK in concert with Dok-7 stimulates rapsyn to concentrate and anchor AChR on the postsynaptic membrane and interacts with other proteins implicated in the assembly and maintenance of the neuromuscular junction. LRP4 also functions as an inhibitor of Wnt/beta-catenin signaling. The identified mutations in LRP4 are located at the edge of its 3rd beta-propeller domain and decrease binding affinity of LRP4 for both MuSK and agrin. Mutations in the LRP4 3rd beta-propeller domain were previously reported to impair Wnt signaling and cause bone diseases including Cenani–Lenz syndactyly syndrome and sclerosteosis-2. By analyzing naturally occurring and artificially introduced mutations in the LRP4 3rd beta-propeller domain, we show that the edge of the domain regulates the MuSK signaling whereas its central cavity governs Wnt signaling. We conclude that LRP4 is a new CMS disease gene and that the 3rd beta propeller domain of LRP4 mediates the two signaling pathways in a position-specific manner. PMID:24234652

  1. Ballistic evaluationof LOVA propellant in high calibre gun

    Directory of Open Access Journals (Sweden)

    A.G.S. Pillai

    2001-04-01

    Full Text Available 'This paper presents the data obrained on dynamic firing of a cellulose acetate binder-based low vulnerability ammunition (LOV A propellant using 120 mm fin-stabilised armour piercing discarding sabot (FSAPDS kinetic energyammunition. An optimised propellant composition formulated ~sing fine RDX as an energetic ingredient and a mixture of cellulose acetate and nitrocellulose as binder was qualified fit for firing in a high calibre gun by its successful static evaluation for absolute ballistics using high pressure closed vessel technique. Dynamic firing of the propellant processed in heptatubular geometry was undertaken to assess the propellant charge mass. This propellant achieved higher muzzle velocity as compared to the standard NQ/M119 triple-base propellant while meeting the non-vulnerability characteristics convincingly.

  2. STRESS ANALYSIS OF COMPOSITE PROPELLER BY USING FINITE ELEMENT ANALYSIS

    Directory of Open Access Journals (Sweden)

    B.SRIDHAR REDDY

    2012-08-01

    Full Text Available Present work proposes a methodology to design a propeller with a metal and composite material to analyze its strength and deformation using Ansys software. In order to evaluate the effectiveness of composite over metals, stress analysis is performed on both composite and metal propeller using Ansys. Proposed methodology showed substantial improvements in metal propellers. The mean deflection, normal stress and shear stress were found for both metallic and composite propeller by using Ansys. From the results, stressanalysis composite propeller is safe resonance phenomenon. In this work effort is made to reduce stress levels so that advantage of weight reduction along with stresses can be obtained. The comparison analysis of metallic and composite propeller was made for the maximum deformation and normal stresses.

  3. Feasibility Study of Processing Estane-based LOVA Gun Propellant

    Directory of Open Access Journals (Sweden)

    M.A.R. Shaikh

    2007-07-01

    Full Text Available Low vulnerability ammunition (LOVA propellant are currently being developed globally toreplace all types of single-base, double-base and triple-base gun propellants, because LOVApropellants possess advantage like low vulnerability without compromising on ballistic properties.The objective of present study is to establish processing of thermoplastic elastomer (TPE;estane-based LOVA gun propellant in cord/heptatubular geometry.  Keeping in view variousadvantages of TPE such as simple processing, greater dimensional stability, lower productionlosses, superior insensitivity, and mechanical properties of the propellants, estane 5731(polyurethane-ester-MDI, aromatic polyester is selected for feasibility study as a binder inLOVA-based gun propellant composition, processed by solvent and semi-solvent methods andcompared feasibility of processing as well as their evaluation wrt ballistics, vulnerability, andmechanical properties. The results indicate that gun propellants processed by semi-solventmethod and extruded at elevated temperatures exhibit better ballistics, mechanical, andvulnerability properties.

  4. Preliminary Determination of Propeller Aerodynamic Characteristics for Small Aeroplanes

    Directory of Open Access Journals (Sweden)

    S. Slavík

    2004-01-01

    Full Text Available This paper deals with preliminary determination of propeller thrust and power coefficients depending on the advance ratio by means of some representative geometric parameters of the blade at a specific radius: propeller blade chord and blade angle setting at 70 % of the top radius, airfoil thickness at the radius near the tip and the position of the maximum blade width. A rough estimation of the non-linear influence of propeller blades number is included.The published method is based on Lock`s model of the characteristic section and the Bull-Bennett lift and drag propeller blade curves. Lock`s integral decomposition factors and the loss factor were modified by the evolution of the experimental propeller characteristics. The numerical-obtained factors were smoothed and expressed in the form of analytical functions depending on the geometric propeller blade parameters and the advance ratio.

  5. Spark-integrated propellant injector head with flashback barrier

    Science.gov (United States)

    Mungas, Gregory Stuart (Inventor); Fisher, David James (Inventor); Mungas, Christopher (Inventor)

    2012-01-01

    High performance propellants flow through specialized mechanical hardware that allows for effective and safe thermal decomposition and/or combustion of the propellants. By integrating a sintered metal component between a propellant feed source and the combustion chamber, an effective and reliable fuel injector head may be implemented. Additionally the fuel injector head design integrates a spark ignition mechanism that withstands extremely hot running conditions without noticeable spark mechanism degradation.

  6. Burning Rate Studies of Energetic Double Base Propellants

    Directory of Open Access Journals (Sweden)

    V. K. Bhat

    1986-01-01

    Full Text Available A systematic study was carried out on the combustion characteristics of CMDB propellants containing ammonium nitrate, ammonium perchlorate, potassium nitrate, potassium perchlorate, RDX and PETN. While ammonium and potassium perchlorates increased burning rates, other additives maintained either the same burning rate or reduced burning rates marginally. Propellants containing these additives showed marginally higher peak temperatures, indicating interaction among the species of double base propellant decomposition and those of additives.

  7. Wind tunnel tests of stratospheric airship counter rotating propellers

    OpenAIRE

    Yaxi Chen; Peiqing Liu; Zhihao Tang; Hao Guo

    2015-01-01

    Aerodynamic performance of the high-altitude propeller, especially the counter rotation effects, is experimentally studied. Influences of different configurations on a stratospheric airship, included 2-blade counter-rotating propeller (CRP), dual 2-blade single rotation propellers (SRPs) and 4-blade SRP, are also indicated. This research indicates that the effect of counter rotation can greatly improve the efficiency. It shows that the CRP configuration results in a higher efficiency than the...

  8. Study on the Detonation Danger of Solid Propellants

    Institute of Scientific and Technical Information of China (English)

    黄风雷; 张宝(金平)

    2004-01-01

    A measurement system to study shock initiation behavior of solid propellants was established experimentally. By using this system, the study on shock initiation to the recovered solid propellants with micro damage was performed, especially on the deflagration to denonation transition (DDT) process of solid propellants under both the strong and weak conditions of restriction. The experimental results show that there is a fully compression region in DDT process.

  9. Feasibility Study of Processing Estane-based LOVA Gun Propellant

    OpenAIRE

    M.A.R. Shaikh; R. R. Sanghavi; S. D. Shelar; T. K. Chakraborthy; Amarjit Singh

    2007-01-01

    Low vulnerability ammunition (LOVA) propellant are currently being developed globally toreplace all types of single-base, double-base and triple-base gun propellants, because LOVApropellants possess advantage like low vulnerability without compromising on ballistic properties.The objective of present study is to establish processing of thermoplastic elastomer (TPE);estane-based LOVA gun propellant in cord/heptatubular geometry.  Keeping in view variousadvantages of TPE such as simple processi...

  10. Experimental Validation of a Marine Propeller Thrust Estimation Scheme

    OpenAIRE

    Luca Pivano; Øyvind N. Smogeli; Tor A. Johansen; Thor Inge Fossen

    2007-01-01

    A thrust estimation scheme for a marine propeller has been experimentally tested in waves and with a device that simulates the influence of a vessel hull. The scheme is formed by a nonlinear propeller torque observer and a mapping to generate the thrust from the observed torque. The mapping includes the estimation of the advance number. This is utilized to improve the performance when the propeller is lightly loaded. The advance speed is assumed to be unknown, and only measurements of shaft s...

  11. EXPERIMENTAL INVESTIGATION OF A VARIABLE GEOMETRY DUCTED PROPELLER

    Directory of Open Access Journals (Sweden)

    Tomasz Muszyński

    2013-03-01

    Full Text Available The paper presents preliminary results of experimental research on the variable geometry of a ducted propeller. The purpose of this work is explore the area of ​​application of the ducted propellers of variable geometry. The paper contains the description of a test station and a model, initial tests’ results of some selected geometries intakes and exit vents in comparison with an open propeller.

  12. Numerical analysis of ice impacts on azimuth propeller

    OpenAIRE

    Kim, Gary G.

    2013-01-01

    Approved for public release; distribution is unlimited Incorporating an azimuth/podded propulsion into an ice-capable ship brings concern in the propellers durability and lifecycle. An ice impact model was constructed to have a better understanding of collisions occurring between ice and azimuth/podded propeller for ice operation ships. A typical propeller profile was created using MATLAB and modeled in SolidWorks using realistic material properties. The ANSYS Explicit Dynamics solver was ...

  13. Design and Analysis of Composite Propeller Blade for Aircraft

    OpenAIRE

    Madhusudhan BM; Dr P.V Srihari

    2014-01-01

    Fiber reinforced composites is used for twin blade propeller because of its high strength, low temperature applications. Fiber has to be oriented in the loading direction while designing the composite propeller blade. The blade geometry and design are more complex involving many controlling parameters. In the present work a methodology to design a composite propeller to analyze its strength and deformation using ANSYS software. The weight of the composite blade is reduced comp...

  14. Rotating Camera System for Propeller and Rotor Blade Deformation Measurements

    OpenAIRE

    Boden, Fritz; Stasicki, Boleslaw; Szypula, Marek

    2015-01-01

    Within the EU project AIM² project a rotating stereoscopic camera system was designed, build and successfully flight tested in order to apply the non-intrusive Image Pattern Correlation Technique (IPCT) to 360° propeller deformation measurements. The complete system was affixed to the axis of the aircraft engine rotating together with the propeller at its full rotational speed. It enabled the direct measurement of the propeller blades shape as well as its local pitch angle under real operatin...

  15. EXPERIMENTAL INVESTIGATION OF A VARIABLE GEOMETRY DUCTED PROPELLER

    OpenAIRE

    Tomasz Muszyński; Piotr Strzelczyk

    2013-01-01

    The paper presents preliminary results of experimental research on the variable geometry of a ducted propeller. The purpose of this work is explore the area of ​​application of the ducted propellers of variable geometry. The paper contains the description of a test station and a model, initial tests’ results of some selected geometries intakes and exit vents in comparison with an open propeller.

  16. Analysis of the propeller wake by pressure and velocity correlation

    OpenAIRE

    Felli, Mario; Di Felice, Fabio; Guj, Giulio; Camussi, Roberto

    2004-01-01

    In the present study an experimental analysis of the velocity and pressure fields behind a marine propeller, in non cavitating regime is reported. Velocity measurements were performed in phase with the propeller angle by using 2D Particle Image Velocimetry (2D-PIV). Measurements were carried out arranging the light sheet along the mid longitudinal plane of the propeller, to investigate the evolution of the axial and the radial velocity components, from the blade trailing edge up to 2 diameter...

  17. EFD and CFD Characterization of a CLT Propeller

    OpenAIRE

    Daniele Bertetta; Stefano Brizzolara; Edward Canepa; Stefano Gaggero; Michele Viviani

    2012-01-01

    In the present paper an experimental and numerical analysis of an unconventional CLT propeller is carried out. Two different numerical approaches, a potential panel method and an RANSE solver, are employed. Cavitation tunnel experiments are carried out in order to measure, as usual, thrust, torque, and cavity extension for different propeller working points. Moreover, LDV measurements are performed to have a deep insight into the complex wake behind the propeller and to analyze the dynamics o...

  18. Motion Correction in PROPELLER and Turboprop-MRI

    OpenAIRE

    Tamhane, Ashish A.; Arfanakis, Konstantinos

    2009-01-01

    PROPELLER and Turboprop-MRI are characterized by greatly reduced sensitivity to motion, compared to their predecessors, fast spin-echo and gradient and spin-echo, respectively. This is due to the inherent self-navigation and motion correction of PROPELLER-based techniques. However, it is unknown how various acquisition parameters that determine k-space sampling affect the accuracy of motion correction in PROPELLER and Turboprop-MRI. The goal of this work was to evaluate the accuracy of motion...

  19. Numerical Modelling of Regenerative Liquid Propellant Guns with Annular Piston

    Directory of Open Access Journals (Sweden)

    K. J. Daniel

    1997-01-01

    Full Text Available The development of regenerative liquid propellant guns (RLPGs needs due consideration of numerous interdependent parameters that affect its performance. To help in this task, computer simulation was undertaken to predict internal ballistics of a conceptual liquid propellant gun. The expected pressure and other important parameters are documented which serve as an aid to the hardware, design of the regenerative liquid propellant guns.

  20. High Impulse Nanoparticulate-Based Gel Propellants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed Small Business Innovative Research (SBIR) Phase I addresses the development of advanced gel propellants and determination of their suitability for...

  1. Development of a Marine Propeller With Nonplanar Lifting Surfaces

    DEFF Research Database (Denmark)

    Andersen, Poul; Friesch, Jürgen; Kappel, Jens J.;

    2005-01-01

    The principle of non-planar lifting surfaces is applied to the design of modern aircraft wings to obtain better lift to drag ratios. Whereas a pronounced fin or winglet at the wingtip has been developed for aircraft, the application of the nonplanar principle to marine propellers, dealt with in...... this paper, has led to the KAPPEL propeller with blades curved toward the suction side integrating the fin or winglet into the propeller blade. The combined theoretical, experimental, and practical approach to develop and design marine propellers with nonplanar lifting surfaces has resulted in...

  2. Propeller Test Facilities  

    Data.gov (United States)

    Federal Laboratory Consortium — Description: Three electrically driven whirl test stands are used to determine propeller (or other rotating device) performance at various rotational speeds. These...

  3. Solid rocket propellant waste disposal/ingredient recovery study

    Science.gov (United States)

    Mcintosh, M. J.

    1976-01-01

    A comparison of facility and operating costs of alternate methods shows open burning to be the lowest cost incineration method of waste propellant disposal. The selection, development, and implementation of an acceptable alternate is recommended. The recovery of ingredients from waste propellant has the probability of being able to pay its way, and even show a profit, when large consistent quantities of composite propellant are available. Ingredients recovered from space shuttle waste propellant would be worth over $1.5 million. Open and controlled burning are both energy wasteful.

  4. CFD and FEM Model of an Underwater Vehicle Propeller

    Directory of Open Access Journals (Sweden)

    Chruściel Tadeusz

    2014-10-01

    Full Text Available Within the framework of the project for design and optimization of the Remotely Operated Vehicle (ROV, research on its propulsion has been carried out. Te entire project was supported by CFD and FEM calculations taking into account the characteristics of the underwater vehicle. One of the tasks was to optimize the semi-open duct for horizontal propellers, which provided propulsion and controllability in horizontal plane. In order to create a measurable model of this task it was necessary to analyze numerical methodology of propeller design, along with the structure of a propellers with nozzles and contra-rotating propellers. It was confronted with theoretical solutions which included running of the analyzed propeller near an underwater vehicle. Also preliminary qualitative analyses of a simplified system with contra-rotating propellers and a semi-open duct were carried out. Te obtained results enabled to make a decision about the ROVs duct form. Te rapid prototyping SLS (Selective Laser Sintering method was used to fabricate a physical model of the propeller. As a consequence of this, it was necessary to verify the FEM model of the propeller, which based on the load obtained from the CFD model. Te article contains characteristics of the examined ROV, a theoretical basis of propeller design for the analyzed cases, and the results of CFD and FEM simulations.

  5. Cryogenic Propellant Storage and Handling Efficiency Improvement Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The project determined specific performance metrics and discrete technology development goals with which to gage proposed investments in ground propellant systems...

  6. Clogging of Manifolds with Evaporatively Frozen Propellants. Part 2; Analysis

    Science.gov (United States)

    Simmon, J. A.; Gift, R. D.; Spurlock, J. M.

    1966-01-01

    The mechanisms of evaporative freezing of leaking propellant and the creation of flow stoppages within injector manifolds is discussed. A quantitative analysis of the conditions, including the existence of minimum and maximum leak rates, for the accumulation of evaporatively frozen propellant is presented. Clogging of the injector manifolds of the Apollo SPS and the Gemini OAMS engines by the freezing of leaking propellant is predicted and the seriousness of the consequences are discussed. Based on the analysis a realistic evaluation of selected techniques to eliminate flow stoppages by frozen propellant is made.

  7. Kappel桨与传统螺旋桨噪声对比试验%Contrast experiments on the propeller noise of the Kappel propeller and the conventional propeller

    Institute of Scientific and Technical Information of China (English)

    宋晗; 王睿; 熊鹰

    2015-01-01

    To test the noise performance of the Kappel propeller, background noise and propeller noise contrast tests are carried out in the NUE cavitation tunnel. Both wet condition noise and the cavitation noise of the two propellers are measured in the tests under sixteen different working conditions. The analy-sis based on the measurement results indicates that the acoustics performance of the NEU cavitation tunnel satisfies the requirements of the tests, and higher signal-to-noise ratio can be achieved in the frequency range between 1 kHz and 20 kHz. The SPL of the Kappel propeller noise equals to the conventional propel-ler noise under the wet condition. With the same cavitation number, the SPL of the Kappel propeller cavita-tion noise is higher than that of the conventional propeller. Meanwhile, the pattern of the Kappel propeller cavitation is more precise than that of the conventional propeller. It is concluded that the cavitation perfor-mance of the Kappel propeller is poorer than that of the conventional propeller. To improve the cavitation performance, the relationship between pitch and camber should be comprehensively considered in the pro-cess of Kappel propeller designing.%为检验Kappel桨的噪声性能,在海军工程大学空泡水洞进行背景噪声测量及2种桨模噪声对比试验.本次试验共设计16组工况,分别测量2种桨在无空泡和有空泡时的噪声.由测量结果分析可知,海军工程大学空泡水洞的声学性能满足试验要求,噪声信号在1~20 kHz范围内可获得较高的信噪比.无空泡时,Kappel桨与传统桨的辐射噪声相当;在相同转速空泡数σn下,Kappel桨的空化辐射噪声高于传统螺旋桨的,同时观察其空泡形态,与传统螺旋桨相比Kappel桨的空泡形态要为剧烈,表明在空泡性能方面Kappel桨要低于传统螺旋桨,在Kappel桨的设计过程中应综合考虑螺距与拱弧的关系以改善Kappel桨的空泡性能.

  8. Levered and unlevered Beta

    OpenAIRE

    Fernandez, Pablo

    2003-01-01

    We prove that in a world without leverage cost the relationship between the levered beta ( L) and the unlevered beta ( u) is the No-costs-of-leverage formula: L = u + ( u - d) D (1 - T) / E. We also analyze 6 alternative valuation theories proposed in the literature to estimate the relationship between the levered beta and the unlevered beta (Harris and Pringle (1985), Modigliani and Miller (1963), Damodaran (1994), Myers (1974), Miles and Ezzell (1980), and practitioners) and prove that all ...

  9. Betting Against Beta

    DEFF Research Database (Denmark)

    Frazzini, Andrea; Heje Pedersen, Lasse

    .S. equities, 20 international equity markets, Treasury bonds, corporate bonds, and futures; (2) A betting-against-beta (BAB) factor, which is long leveraged low beta assets and short high-beta assets, produces significant positive risk-adjusted returns; (3) When funding constraints tighten, the return of the...

  10. Forward-Looking Betas

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Jacobs, Kris; Vainberg, Gregory

    Few issues are more important for finance practice than the computation of market betas. Existing approaches compute market betas using historical data. While these approaches differ in terms of statistical sophistication and the modeling of the time-variation in the betas, they are all backward-...

  11. Image domain propeller fast spin echo☆

    Science.gov (United States)

    Skare, Stefan; Holdsworth, Samantha J.; Lilja, Anders; Bammer, Roland

    2013-01-01

    A new pulse sequence for high-resolution T2-weighted (T2-w) imaging is proposed –image domain propeller fast spin echo (iProp-FSE). Similar to the T2-w PROPELLER sequence, iProp-FSE acquires data in a segmented fashion, as blades that are acquired in multiple TRs. However, the iProp-FSE blades are formed in the image domain instead of in the k-space domain. Each iProp-FSE blade resembles a single-shot fast spin echo (SSFSE) sequence with a very narrow phase-encoding field of view (FOV), after which N rotated blade replicas yield the final full circular FOV. Our method of combining the image domain blade data to a full FOV image is detailed, and optimal choices of phase-encoding FOVs and receiver bandwidths were evaluated on phantom and volunteers. The results suggest that a phase FOV of 15–20%, a receiver bandwidth of ±32–63 kHz and a subsequent readout time of about 300 ms provide a good tradeoff between signal-to-noise ratio (SNR) efficiency and T2 blurring. Comparisons between iProp-FSE, Cartesian FSE and PROPELLER were made on single-slice axial brain data, showing similar T2-w tissue contrast and SNR with great anatomical conspicuity at similar scan times –without colored noise or streaks from motion. A new slice interleaving order is also proposed to improve the multislice capabilities of iProp-FSE. PMID:23200683

  12. Thermal Vacuum Test Correlation of A Zero Propellant Load Case Thermal Capacitance Propellant Gauging Analytics Model

    Science.gov (United States)

    McKim, Stephen A.

    2016-01-01

    This thesis describes the development and test data validation of the thermal model that is the foundation of a thermal capacitance spacecraft propellant load estimator. Specific details of creating the thermal model for the diaphragm propellant tank used on NASA's Magnetospheric Multiscale spacecraft using ANSYS and the correlation process implemented to validate the model are presented. The thermal model was correlated to within plus or minus 3 degrees Centigrade of the thermal vacuum test data, and was found to be relatively insensitive to uncertainties in applied heat flux and mass knowledge of the tank. More work is needed, however, to refine the thermal model to further improve temperature predictions in the upper hemisphere of the propellant tank. Temperatures predictions in this portion were found to be 2-2.5 degrees Centigrade lower than the test data. A road map to apply the model to predict propellant loads on the actual MMS spacecraft toward its end of life in 2017-2018 is also presented.

  13. 75 FR 34390 - Airworthiness Directives; McCauley Propeller Systems Five-Blade Propeller Assemblies

    Science.gov (United States)

    2010-06-17

    ... Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78). Examining the AD Docket You...-14388. (70 FR 71756, November 30, 2005). That AD requires: Removing any propeller hub from service that.... Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034,...

  14. Swarming of self-propelled camphor boats

    Science.gov (United States)

    Heisler, Eric; Suematsu, Nobuhiko J.; Awazu, Akinori; Nishimori, Hiraku

    2012-05-01

    When an ensemble of self-propelled camphor boats move in a one-dimensional channel, they exhibit a variety of collective behaviors. Under certain conditions, the boats tend to cluster together and move in a relatively tight formation. This type of behavior, referred to as clustering or swarming here, is one of three types recently observed in experiment. Similar clustering behavior is also reproduced in simulations based on a simple theoretical model. Here we examine this model to determine the clustering mechanism and the conditions under which clustering occurs. We also propose a method of quantifying the behavior that may be used in future experimental work.

  15. Propellant Analysis and Distillation Unit Design

    Science.gov (United States)

    Barragan, Michelle H.; Spangler, Cindy; Barrera, Louis K.

    2007-01-01

    The NASA White Sands Test Facility (WSTF) routinely operates hypergolic propulsion systems. Some of the onsite activities include performing long duration studies on the operational life of these systems. A few of them have been in use for over twenty years. During this span of time contamination has built up in the propellant and some of the distribution infrastructure. This study investigated the nature of this contamination, the pathology of its generation, and developed a process for removal of the contamination that was cost efficient with minimal waste generation.

  16. Marine Propeller Manufacturing – A New Approach

    Directory of Open Access Journals (Sweden)

    Yonas Mitiku Degu

    2016-08-01

    Full Text Available Laser Engineered Net Shaping (LENS is one of the rapid prototyping manufacturing process for producing metal parts directly from Computer Aided Design (CAD files, In this approach to fabricate the ship propeller by layer additive methods. The LENS technology is unique in that fully dense metal components with material properties that are similar to that of wrought materials can be fabricated. The LENS process has the potential to dramatically reduce the time and cost required realizing functional metal parts. In addition, the process can fabricate complex internal features not possible using existing manufacturing processes.

  17. Strings of droplets propelled by coherent waves

    CERN Document Server

    Filoux, B; Vandewalle, N

    2015-01-01

    Bouncing walking droplets possess fascinating properties due to their peculiar wave/particule interaction. In order to study such walkers in a 1d system, we considered the case of one or more droplets in an annular cavity. We show that, in this geometry, walking droplets form a string of synchronized bouncing droplets that share a common coherent wave propelling the group at a speed faster than single walkers. The formation of this coherent wave and the collective behavior of droplets is captured by a model.

  18. Two-sphere low Reynold's propeller

    OpenAIRE

    Najafi, Ali; Zargar, Rojman

    2010-01-01

    A three-dimensional model of a low-Reynold's swimmer is introduced and analyzed in this paper. This model consists of two large and small spheres connected by two perpendicular thin rods. The geometry of this system is motivated by the microorganisms that use a single tail to swim, the large sphere represents the head of microorganism and the small sphere resembles its tail. Each rod changes its length and orientation in a non-reciprocal manner that effectively propel the system. Translationa...

  19. Noise constraints effecting optimal propeller designs

    Science.gov (United States)

    Miller, C. J.; Sullivan, J. P.

    1985-01-01

    A preliminary design tool for advanced propellers was developed combining a fast vortex lattice aerodynamic analysis, a fast subsonic point source noise analysis, and an optimization scheme using a conjugate directions method. Twist, chord and sweep distributions are optimized to simultaneously improve both the aerodynamic performance and the noise observed at a fixed relative position. The optimal noise/performance tradeoffs for straight and advanced concept blades are presented. The techniques used include increasing the blade number, blade sweep, reducing the rotational speed, shifting the spanwise loading and diameter changes.

  20. WOW: light print, light propel, light point

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Bañas, Andrew Rafael; Aabo, Thomas;

    2012-01-01

    anywhere in a sample at any orientation using real-time 3D optical micromanipulation with six degrees of freedom. One of the key aspects of our demonstrated WOWs is the change in direction of in-coupled light and the marked increase in numerical aperture of the out-coupled light. Hence, each light...... propelled WOW can tap from a relatively broad incident beam and generate a much more tightly confined light at its tip. The presentation contains both numerical simulations related to the propagation of light through a WOW and preliminary experimental demonstrations on our BioPhotonics Workstation...

  1. Development of controllable pitch propeller mechanism for small high speed boats; Kogata kosokuteiyo kahen pitch propeller kiko no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Y.; Shiba, H.; Inoue, R.; Mori, T. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

    1995-12-20

    For improving the navigating performance of racing boats, a controllable pitch propeller mechanism has been developed, capable of responding to changes in the propeller load and of making good use of the engine performance. The effort aimed at the optimization of the propeller load to follow changes in surrounding conditions such as weather and the resultant sea roughness, the engine performance, and at the improvement of acceleration features. The blade angle is made smaller for reduced torque absorption at a low engine speed and, as the engine gathers speed, the blade angle is changed to the optimum for rapid acceleration to the maximum boat speed. The blade angle is made smaller upon deceleration. The mechanism has been designed so that it may be added on a boat rigged with a fixed pitch propeller. The design enables a propeller to properly respond to changes in the propeller load without pre-run replacement or shape-changing work. When this propeller`s performance is optimized to match the engine characteristics, there will be a propelling device with its performance further advanced. This design expands the range of engine performance in which usable one may be found. 6 refs., 6 figs., 1 tab.

  2. Green Propellant Landing Demonstration at U.S. Range

    Science.gov (United States)

    Mulkey, Henry W.; Miller, Joseph T.; Bacha, Caitlin E.

    2016-01-01

    The Green Propellant Loading Demonstration (GPLD) was conducted December 2015 at Wallops Flight Facility (WFF), leveraging work performed over recent years to bring lower toxicity hydrazine replacement green propellants to flight missions. The objective of this collaboration between NASA Goddard Space Flight Center (GSFC), WFF, the Swedish National Space Board (SNSB), and Ecological Advanced Propulsion Systems (ECAPS) was to successfully accept LMP-103S propellant at a U.S. Range, store the propellant, and perform a simulated flight vehicle propellant loading. NASA GSFC Propulsion (Code 597) managed all aspects of the operation, handling logistics, preparing the procedures, and implementing the demonstration. In addition to the partnership described above, Moog Inc. developed an LMP-103S propellant-compatible titanium rolling diaphragm flight development tank and loaned it to GSFC to act as the GPLD flight vessel. The flight development tank offered the GPLD an additional level of flight-like propellant handling process and procedures. Moog Inc. also provided a compatible latching isolation valve for remote propellant expulsion. The GPLD operation, in concert with Moog Inc. executed a flight development tank expulsion efficiency performance test using LMP-103S propellant. As part of the demonstration work, GSFC and WFF documented Range safety analyses and practices including all elements of shipping, storage, handling, operations, decontamination, and disposal. LMP-103S has not been previously handled at a U.S. Launch Range. Requisite for this activity was an LMP-103S Risk Analysis Report and Ground Safety Plan. GSFC and WFF safety offices jointly developed safety documentation for application into the GPLD operation. The GPLD along with the GSFC Propulsion historical hydrazine loading experiences offer direct comparison between handling green propellant versus safety intensive, highly toxic hydrazine propellant. These described motives initiated the GPLD operation

  3. New high energetic composite propellants for space applications: refrigerated solid propellant

    Science.gov (United States)

    Franson, C.; Orlandi, O.; Perut, C.; Fouin, G.; Chauveau, C.; Gökalp, I.; Calabro, M.

    2009-09-01

    Cryogenic solid propellants (CSP) are a new kind of chemical propellants that use frozen products to ensure the mechanical resistance of the grain. The objective is to combine the high performances of liquid propulsion and the simplicity of solid propulsion. The CSP concept has few disadvantages. Storability is limited by the need of permanent cooling between motor loading and firing. It needs insulations that increase the dry mass. It is possible to limit significantly these drawbacks by using a cooling temperature near the ambient one. It will permit not to change the motor materials and to minimize the supplementary dry mass due to insulator. The designation "Refrigerated Solid Propellant" (RPS) is in that case more appropriate as "Cryogenic Solid Propellant." SNPE Matériaux Energétiques is developing new concept of composition e e with cooling temperature as near the ambient temperature as possible. They are homogeneous and the main ingredients are hydrogen peroxide, polymer and metal or metal hydride, they are called "HydroxalaneTM." This concept allows reaching a high energy level. The expected specific impulse is between 355 and 375 s against 315 s for hydroxyl-terminated polybutadiene (HTPB) / ammonium perchlorate (AP) / Al composition. However, the density is lower than for current propellants, between 1377 and 1462 kg/m3 compared to around 1800 kg/m3 . This is an handicap only for volume-limited application. Works have been carried out at laboratory scale to define the quality of the raw materials and the manufacturing process to realize sample and small grain in a safer manner. To assess the process, a small grain with an internal bore had been realized with a composition based on aluminum and water. This grain had shown very good quality, without any defect, and good bonding properties on the insulator.

  4. REVERSE ENGINEERING IN MODELING OF AIRCRAFT PROPELLER BLADE - FIRST STEP TO PRODUCT OPTIMIZATION

    OpenAIRE

    Muhammad Yasir Anwar; Shahid Ikramullah; Farrukh Mazhar

    2014-01-01

    ABSTRACT: Propeller aircrafts have had many ups and downs throughout their use in the aviation history. Due to the current economic recession and price hikes in fuels, propeller aircrafts may yet again be a choice for aerial transport and has thus re-emerged as an active area for research. On modern propeller aircrafts old aluminum propellers are being replaced with fiber reinforced composite propellers. However, owing to their reliability, strength, and integrity, aluminum propellers are sti...

  5. Nuclear thermal rocketry using indigenous Martian propellants

    Science.gov (United States)

    Zubrin, Robert M.

    A preliminary examination of a concept for a Mars and outer solar system exploratory vehicle is presented. Propulsion is provided by utilizing a nuclear thermal reactor to heat a propellant volatile indigenous to the destination world to form a high thrust rocket exhaust. Candidate propellants, whose performance, materials compatibility, and ease of acquisition are examined and include carbon dioxide, water, methane, nitrogen, carbon monoxide, and argon. Ballistics and winged supersonic configurations are discussed. It is shown that the use of this method of propulsion potentially offers high payoff to a manned Mars mission. This is accomplished by sharply reducing the initial mission mass required in mobility in traveling about the planet through the use of a vehicle that utilized in combination with a hydrogen-fueled nuclear-thermal interplanetary launch. By utilizing such a system in the outer solar system, a low level aerial reconnaissance of Titan combined with a multiple sample return from nearly every satellite of Saturn can be accomplished in a single launch of a Titan 4 or the Space Transportation System (STS). Similarly a multiple sample return from Callisto, Ganymedes and Europa can also be accomplished in one launch of a Titan 4 or the STS.

  6. Nuclear thermal rockets using indigenous extraterrestrial propellants

    International Nuclear Information System (INIS)

    A preliminary examination of a concept for a Mars and outer solar system exploratory vehicle is presented. Propulsion is provided by utilizing a nuclear thermal reactor to heat a propellant volatile indigenous to the destination world to form a high thrust rocket exhaust. Candidate propellants, whose performance, materials compatibility, and ease of acquisition are examined and include carbon dioxide, water, methane, nitrogen, carbon monoxide, and argon. Ballistics and winged supersonic configurations are discussed. It is shown that the use of this method of propulsion potentially offers high payoff to a manned Mars mission. This is accomplished by sharply reducing the initial mission mass required in low earth orbit, and by providing Mars explorers with greatly enhanced mobility in traveling about the planet through the use of a vehicle that can refuel itself each time it lands. Thus, the nuclear landing craft is utilized in combination with a hydrogen-fueled nuclear-thermal interplanetary launch. By utilizing such a system in the outer solar system, a low level aerial reconnaissance of Titan combined with a multiple sample return from nearly every satellite of Saturn can be accomplished in a single launch of a Titan 4 or the Space Transportation System (STS). Similarly a multiple sample return from Callisto, Ganymede, and Europa can also be accomplished in one launch of a Titan 4 or the STS

  7. Propeller-driven Outflows and Disk Oscillations

    CERN Document Server

    Romanova, M M; Koldoba, A V; Lovelace, R V E

    2005-01-01

    We report the discovery of propeller-driven outflows in axisymmetric magnetohydrodynamic simulations of disk accretion to rapidly rotating magnetized stars. Matter outflows in a wide cone and is centrifugally ejected from the inner regions of the disk. Closer to the axis there is a strong, collimated, magnetically dominated outflow of energy and angular momentum carried by the open magnetic field lines from the star. The ``efficiency'' of the propeller may be very high in the respect that most of the incoming disk matter is expelled from the system in winds. The star spins-down rapidly due to the magnetic interaction with the disk through closed field lines and with corona through open field lines. Diffusive and viscous interaction between magnetosphere and the disk are important: no outflows were observed for very small values of the diffusivity and viscosity. These simulation results are applicable to the early stages of evolution of classical T Tauri stars and to different stages of evolution of cataclysmi...

  8. Current state of the art of HNF based composite propellants

    NARCIS (Netherlands)

    Ciucci, A.; Frota, O.; Welland, W.H.M.; Heijden, A.E.D.M. van der; Leeming, B.; Bellerby, J.M.; Brotzu, A.

    2004-01-01

    The main activities currently performed for the development of HNF-based propellants are presented. The objectives and approach adopted are described. The results obtained on the HNF decomposition mechanism and on the re- and co-crystallisation of HNF with potential propellant ingredients are presen

  9. 30 CFR 57.4260 - Underground self-propelled equipment.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground self-propelled equipment. 57.4260... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control Firefighting Equipment § 57.4260 Underground self-propelled equipment. (a)...

  10. Propellant and Purge System Contamination "2007: A Summer of Fun"

    Science.gov (United States)

    Galloway, Randy

    2010-01-01

    This slide presentation reviews the propellant and purge system contamination that occurred during the summer of 2007 at Stennis Space Center. During this period Multiple propellant/pressurant system contamination events prompted a thorough investigation, the results of which are reviewed.

  11. Self-propelled oil droplets consuming "fuel" surfactant

    DEFF Research Database (Denmark)

    Toyota, Taro; Maru, Naoto; Hanczyc, Martin M;

    2009-01-01

    A micrometer-sized oil droplet of 4-octylaniline containing 5 mol % of an amphiphilic catalyst exhibited a self-propelled motion, producing tiny oil droplets, in an aqueous dispersion of an amphiphilic precursor of 4-octylaniline. The tiny droplets on the surface of the self-propelled droplet wer...

  12. Flow Visualization and Performance Measurements of a Flagellar Propeller

    Institute of Scientific and Technical Information of China (English)

    Hyejin Jeon; Yoon-Cheol Kim; Dongwook Yim; Jung Yul Yoo; Songwan Jin

    2012-01-01

    A new type of propeller that is optimized for low Reynolds numbers is required to propel a small object in a medium where the flow is dominated by viscous rather than inertial forces.A propeller in the shape of a bacterial flagellum seems an appropriate choice for driving a small object.Accordingly,in this study,we visualized the velocity field induced by a spring-like propeller inspired by the Escherichia coli flagellum,using a macroscopic model and applying stereoscopic particle image velocimetry.We also experimentally evaluated the effect of pitch and rotational speed on the performance of this flagellar propeller.Silicone oil,which has a kinematic viscosity 100,000 times that of water,was used as the working fluid to generate a low Reynolds number for the macroscopic model.Thrust,torque,and velocity were measured as functions of pitch and rotational speed,and the efficiency of the propeller was calculated from the measured results.We found that the flagellar propeller reached a maximum efficiency when the pitch angle was approximately 53°.Compared to pitch,rotational speed had a relatively small effect on the efficiency,and the pitch altered the flow pattern behind the rotating propeller.

  13. Emissions of gun propellant compositions with added urea

    NARCIS (Netherlands)

    Driel, C.A. van; Hulst, M. van; Meuken, D.

    2011-01-01

    Addition of certain components to gun propellants may lead to a reduction of the NOx content in combustion gases. This is escribed in the literature based on small scale laboratory research. One of these components is urea. In the investigation described here, propellants have been studied which con

  14. Clinical application of MR PROPELLER technology in artifacts reduction

    International Nuclear Information System (INIS)

    Objective: The aim of this study was to assess the clinical value of PROPELLER (periodically rotated overlapping parallel lines enhanced reconstruction, PROPELLER). Methods: Four sequences of conventionality and PROPELLER axial T2-weighted imaging (T2WI) and/or diffusion weighted imaging (DWI) were performed in ten normal volunteers with head ceaseless motion and 64 clinical subjects. Motion artifacts were observed in 56 patients in unconsciousness and magnetic-sensitive artifacts in other 8 patients with metallic implants. PROPELLER images and the conventionality images were compared. Results: Sixty-four clinical subjects included the cerebral infarction (n=41), brain metastasis (n=3) and other's disorders (n=20). PROPELLER T2WI had clearer and motion-artifact-free images in both volunteers and patients in unconsciousness. In dental treatment cases, magnetic-susceptibility artifacts were greatly reduced to an accepted level. Comparing with conventional sequences, PROPELLER T2WI/DWI sequences showed promising feature in reduction of artifacts and distinctly defined pathological profile. Conclusion: MR PROPELLER technique offers a means of reducing motion and metallic artifacts, and improving image quality. Intracranial pathology is equally or better demonstrated with PROPELLER. (authors)

  15. 14 CFR 35.21 - Variable and reversible pitch propellers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Variable and reversible pitch propellers. 35.21 Section 35.21 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Design and Construction § 35.21 Variable...

  16. 14 CFR 23.1027 - Propeller feathering system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller feathering system. 23.1027 Section 23.1027 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Oil System § 23.1027 Propeller feathering system....

  17. 14 CFR 25.907 - Propeller vibration and fatigue.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller vibration and fatigue. 25.907 Section 25.907 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.907 Propeller vibration and fatigue. This section does not apply...

  18. 14 CFR 25.1153 - Propeller feathering controls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller feathering controls. 25.1153 Section 25.1153 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Powerplant Controls and Accessories § 25.1153 Propeller feathering controls....

  19. 33 CFR 401.16 - Propeller direction alarms.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Propeller direction alarms. 401.16 Section 401.16 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.16 Propeller direction alarms. Every vessel of 1600...

  20. 14 CFR 23.907 - Propeller vibration and fatigue.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller vibration and fatigue. 23.907 Section 23.907 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.907 Propeller vibration and...

  1. 14 CFR 23.33 - Propeller speed and pitch limits.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch limits. 23.33 Section 23.33 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Flight General § 23.33 Propeller speed and pitch limits....

  2. 14 CFR 33.95 - Engine-propeller systems tests.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine-propeller systems tests. 33.95 Section 33.95 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Block Tests; Turbine Aircraft Engines § 33.95 Engine-propeller systems tests. If the engine is designed...

  3. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch controls. 25.1149 Section 25.1149 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Powerplant Controls and Accessories § 25.1149 Propeller speed and...

  4. Solid State MEMS Thrusters Using Electrically Controlled Extinguishable Solid Propellant Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ET Materials, LLC developed the first ever electrically controlled extinguishable solid propellant (ECESP). The original propellant developed under Air Force SBIR...

  5. Development of composite solid propellent using dicyclopentadien binder

    Science.gov (United States)

    Bluestone, Stephen Ray

    Through the history of composite solid propellant binders new chemicals are introduced as binders to improve upon the previous generation. Sometimes this is done to improve upon the flaws or shortcomings of a previous binder. Other time it is to meet a new set of requirements desired by industry. Dicyclopentadiene (DCPD) is a hydrocarbon monomer being considered for its potential as a new binder in the composite propellant industry. The binder of a composite solid propellant is arguably the most important feature of the propellant. It is the binder that provides the majority of the structural characteristics of the propellant while also contributing itself as fuel to the combustion process. A binder in composite propellants must also be able to accept the introduction of a large quantity of solid filler; oxidizer, fuel, and other energetic and non-energetic particles. Many of the composite propellants used in industry today have over 80% of their weight composed of non-binder solid or liquid fillers. These requirements must be met by the binder in some form or fashion to produce a propellant able to compete with binders currently in use. When DCPD is polymerized it produces an extremely tough plastic with excellent tensile and impact strength. Experimentation has found that DCPD is able to support a large quantity of solid materials, over 80% weight of the mixture, while still retaining a great portion of its original strength. When compared to another similarly loaded binder currently used in industry, Hydroxyl-Terminated Polybutadiene (HTPB), it was found that DCPD composite propellant had nearly 1.5 times the stress capacity while still exhibiting over 75% of the strain capacity of HTPB based composite propellant. In addition it was also shown that DCPD composite propellant allows for tailoring of its mechanical properties with the addition of plasticizers. The DCPD based composite propellant also exhibits a burning rate nearly twice that HTPB. These factors

  6. Experimental Simulation for Fracture of Gun Propellant Charge Bed

    Institute of Scientific and Technical Information of China (English)

    RUI Xiao-ting; YUN Lai-feng; WANG Hao; HUANG Ming; CHEN Jian-zhong; CHEN Tao; LIU Jun

    2005-01-01

    The simulation of compression and fracture of charge bed in chamber is one of the key problems in the study of launch safety of gun propellant charge. A new kind of experimental device that can be used for simulation is given. Its structure and operational principle are introduced. Using a semi-closed vessel as a source of compression force, the device can simulate any kind of dynamic environment in a gun propellant charge. Using the low temperature inert gas (N2) as the compression medium, the device can not only ensure that the simulation is real, but also protect the fragmentized propellant from combustion after experiment. Using the device, many simulation experiments have been accomplished, and dynamic environment of propellant fracture is acquired. With the experiments, fragmentized propellant for the compression and fracture of charge bed is obtained. Results of experiments show that the new device can be used to study the principle of the compression and fracture of charge bed.

  7. Propellant management for low thrust chemical propulsion systems

    Science.gov (United States)

    Hamlyn, K. M.; Dergance, R. H.; Aydelott, J. C.

    1981-01-01

    Low-thrust chemical propulsion systems (LTPS) will be required for orbital transfer of large space systems (LSS). The work reported in this paper was conducted to determine the propellant requirements, preferred propellant management technique, and propulsion system sizes for the LTPS. Propellants were liquid oxygen (LO2) combined with liquid hydrogen (LH2), liquid methane or kerosene. Thrust levels of 100, 500, and 1000 lbf were combined with 1, 4, and 8 perigee burns for transfer from low earth orbit to geosynchronous earth orbit. This matrix of systems was evaluated with a multilayer insulation (MLI) or a spray-on-foam insulation. Vehicle sizing results indicate that a toroidal tank configuration is needed for the LO2/LH2 system. Multiple perigee burns and MLI allow far superior LSS payload capability. Propellant settling, combined with a single screen device, was found to be the lightest and least complex propellant management technique.

  8. NUMERICAL INVESTIGATION OF CAVITATION PERFORMANCE OF SHIP PROPELLERS

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhi-feng; FANG Shi-liang

    2012-01-01

    The cavitation performance of propellers is studied based on viscous multiphase flow theories.With a hybrid grid based on Navier-Stokes (N-S) and bubble dynamics equations,some recent validation results are presented in this paper in the predictions of the thrust,the torque and the vapor volume fraction on the back side of propeller blade for a uniform inflow.The numerical predictions of the hydrodynamic performance and the sheet cavitation under several operating conditions for two propellers agree with the corresponding measured data in general.The thrust and the torque are plotted with respect to the advance rate and the cavitation number.The cavitation performance breakdown is closely related to the strong sheet cavitation around propellers.The models with parameters modified are shown to predict the propeller cavitation well.

  9. EFD and CFD Characterization of a CLT Propeller

    Directory of Open Access Journals (Sweden)

    Daniele Bertetta

    2012-01-01

    Full Text Available In the present paper an experimental and numerical analysis of an unconventional CLT propeller is carried out. Two different numerical approaches, a potential panel method and an RANSE solver, are employed. Cavitation tunnel experiments are carried out in order to measure, as usual, thrust, torque, and cavity extension for different propeller working points. Moreover, LDV measurements are performed to have a deep insight into the complex wake behind the propeller and to analyze the dynamics of generated tip vortexes. The numerical/experimental analysis and comparison of results highlight the peculiarities of this kind of propellers, the possibility to increase efficiency and reduce cavitation risk, in order to exploit the design approaches already well proven for conventional propellers also in the case of these unconventional geometries.

  10. 14 CFR 36.9 - Acoustical change: Propeller-driven small airplanes and propeller-driven commuter category...

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Acoustical change: Propeller-driven small airplanes and propeller-driven commuter category airplanes. 36.9 Section 36.9 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT NOISE STANDARDS: AIRCRAFT TYPE AND AIRWORTHINESS CERTIFICATION General §...

  11. Image based measurement techniques for aircraft propeller flow diagnostics: Propeller slipstream investigations at high-lift conditions and thrust reverse

    NARCIS (Netherlands)

    Roosenboom, E.W.M.

    2011-01-01

    The aim of the thesis is to measure the propeller slipstream properties (velocity and vorticity) and to assess the unsteady and instantaneous behavior of the propeller flow field at high disk loadings, zero thrust and thrust reverse using the image based measurement techniques. Along with its implem

  12. Model for predicting noise of propeller fans in air conditioners; Kuchoyo propeller fan no soon hasei model no kento

    Energy Technology Data Exchange (ETDEWEB)

    Hakamaya, N.; Funabashi, S.; Takada, Y. [Hitachi, Ltd., Tokyo (Japan)

    1999-12-25

    A model for predicting noise of propeller fans has been developed experimentally. First, the frequency response of turbulence on the blade of a rotating propeller fan was experimentally measured. Then, propeller fan noise was predicted by this model, which calculates lift fluctuations by Sears's equation and sound pressure in the far field by Curle's equation. The model assumes that the normalized intensity of turbulence (i. e., velocity fluctuation) is small in the high-flow-coefficient range but increases sharply in the low-flow-coefficient range. And the model showed that propeller fan noise depends on averaged relative velocity, intensity of turbulence, and length scale of turbulence. These results agree with the experimental measurements. Accordingly, the model predicts propeller fan noise and noise spectrum over a wide range of flow coefficients with reasonable accuracy. (author)

  13. Simulating propeller and Propeller-Hull Interaction in OpenFOAM

    OpenAIRE

    Mehdipour, Reza

    2014-01-01

    This is a master’s thesis performed at the Department of Shipping and Marine Technology research group in Hydrodynamics at Chalmers University of Technology and is written for the Center for Naval Architecture at the Royal Institute of Technology, KTH.In order to meet increased requirements on efficient ship propulsions with low noise level, it is important to consider the complete system with both the hull and the propeller in the simulation.OpenFOAM (Open Field Operation and Manipulation) p...

  14. Perancangan dan Optimasi Propeller pada Sistem Konversi Energi Arus Laut dengan Metode Propeller Vortex Lattice (PVL)

    OpenAIRE

    Mahmuddin, Faisal

    2015-01-01

    Energi terbarukan semakin marak dimanfaatkan dalam beberapa dekade ini termasuk dengan memanfaatkan sistem konversi energi arus laut. Dalam hubungannya arus laut dapat digunakan untuk menggerakkan propeller yang dapat menghasilkan gaya dorong (thrust) sehingga mampu menghasilkan daya yang dapat disimpan untuk menyuplai kebutuhan listrik di daratan sekitar daerah pesisir termasuk di daerah Selat Pantar, Pulau Pura Nusa Tenggara Timur dimana kecepatan arus laut rata- rata sebesar 1,346 m/s. Dae...

  15. Detonation wave initiation of ram accelerator propellants

    Science.gov (United States)

    Bauer, P.; Knowlen, C.

    The current ram accelerator operations have shown that data on the ability of the propellants to detonate are required. Previous studies examined the efficacy of initiation techniques based on piston impact. The purpose of the present work is to analyze the effects of detonation wave transmission from a detonating mixture into a low sensitivity mixture. One-dimensional modeling based on the analysis of pressure vs particle velocity for the mixtures is used to interpret experimental data. Furthermore, calculations based on chemical kinetics (CHEMKIN code) are provided. Experimental data together with the modeling of the detonation transmission provide some new insight into the limiting conditions necessary to establish a Chapman-Jouguet (CJ) wave in a detonable mixture.

  16. Propeller outflows from an MRI disc

    CERN Document Server

    Lii, Patrick S; Ustyugova, Galina V; Koldoba, Alexander V; Lovelace, Richard V E

    2013-01-01

    We present the results of axisymmetric simulations of MRI-driven accretion onto a rapidly rotating, magnetized star accreting in the propeller regime. The stellar magnetosphere corotates with the star, forming a centrifugal barrier at the disc-magnetosphere boundary which inhibits matter accretion onto the star. Instead, the disc matter accumulates at the disc-magnetosphere interface and slowly diffuses into the inner magnetosphere where it picks up angular momentum and is quickly ejected from the system as an outflow. Due to the interaction of the matter with the magnetosphere, this wind is discontinuous and is launched as discrete plasmoids. If the ejection rate is lower than the disc accretion rate, the matter accumulates at the disc-magnetosphere boundary faster than it can be ejected. In this case, accretion onto the star proceeds through the episodic accretion instability in which episodes of matter accumulation are followed by simultaneous accretion and ejection. During the accretion phase of this inst...

  17. Self-propelled film-boiling liquids

    Science.gov (United States)

    Linke, Heiner; Taormina, Michael; Aleman, Benjamin; Melling, Laura; Dow-Hygelund, Corey; Taylor, Richard; Francis, Matthew

    2006-03-01

    We report that liquids perform self-propelled motion when they are placed in contact with hot surfaces with asymmetric (ratchet-like) topology. Millimeter-sized droplets or slugs accelerate at rates up to 0.1 g and reach terminal velocities of several cm/s, sustained over distances up to a meter. The pumping effect is observed when the liquid is in the film-boiling regime, for many liquids and over a wide temperature range. We propose that liquid motion is driven by a viscous force exerted by vapor flow between the solid and the liquid. This heat-driven pumping mechanism may be of interest in cooling applications, eliminating the need for an additional power source.

  18. Effect of Propellant Combustion on Sapphire

    Directory of Open Access Journals (Sweden)

    Mark L. Bundy

    2000-10-01

    Full Text Available Sapphire (Al2O3 is the window material of choice for laser beam transmission into the combustion chamber of laser-ignited guns. To evaluate the long-term effects of propellant combustion on an Al/sub 2/O/sub 3/ laser window, it is important to know the window temperature during firing. This paper presents temperature data on an Al/sub 2/O/sub 3/ sample located in the breech face of the gun where the laser window would be in a laser-ignited 155 mm(M199 cannon. Al/sub 2/O/sub 3/ sample is a substrate material of a commercially sold thin-film thermocouple, and is therefore thermally, if not optically, representative of an actual Al/sub 2/O/sub 3/ laser window.

  19. Two-sphere low Reynold's propeller

    CERN Document Server

    Najafi, Ali

    2010-01-01

    A three-dimensional model of a low-Reynold's swimmer is introduced and analyzed in this paper. This model consists of two large and small spheres connected by two perpendicular thin rods. The geometry of this system is motivated by the microorganisms that use a single tail to swim, the large sphere represents the head of microorganism and the small sphere resembles its tail. Each rod changes its length and orientation in a non-reciprocal manner that effectively propel the system. Translational and rotational velocities of the swimmer are studied for different values of parameters. Our findings show that by changing the parameters we can adjust both the velocity and the direction of motion of the swimmer.

  20. Efficient kinematics for jet-propelled swimming

    Science.gov (United States)

    Alben, Silas; Miller, Laura; Peng, Jifeng

    2013-11-01

    We use vortex sheet and viscous simulations and an analytical model to search for efficient jet-propelled swimming kinematics at large Reynolds numbers (1000 and above). We prescribe different power-law kinematics for the bell contraction and expansion. In the simulations, two types of efficient kinematics are found: a bell radius velocity which is a nearly linear function of time, and a ``burst-and-coast'' kinematics. The analytical model studies the contraction phase only, and finds that the efficiency-optimizing kinematics transition from a nearly linear bell radius velocity (similar to the numerics) for small-to-moderate output power to an exponentially-decaying bell radius velocity for large output power.

  1. Rheological Characterization of Ethanolamine Gel Propellants

    Science.gov (United States)

    V. S Jyoti, Botchu; Baek, Seung Wook

    2016-07-01

    Ethanolamine is considered to be an environmentally friendly propellant system because it has low toxicity and is noncarcinogenic in nature. In this article, efforts are made to formulate and prepare ethanolamine gel systems, using pure agarose and hybrids of paired gelling agents (agarose + polyvinylpyrrolidine (PVP), agarose + SiO2, and PVP + SiO2), that exhibit a measurable yield stress, thixotropic behavior under shear rate ranges of 1-1,000 s-1 and a viscoelastic nature. To achieve these goals, multiple rheological experiments (including flow and dynamic studies) are performed. In this article, results are presented from experiments measuring the apparent viscosity, yield stress, thixotropy, dynamic strain, frequency sweep, and tan δ behaviors, as well as the effects of the test temperature, in the gel systems. The results show that the formulated ethanolamine gels are thixotropic in nature with yield stress between 30 and 60 Pa. The apparent viscosity of the gel decreases as the test temperature increases, and the apparent activation energy is the lowest for the ethanolamine-(PVP + SiO2) gel system. The dynamic rheology study shows that the type of gellant, choice of hybrid gelling materials and their concentration, applied frequencies, and strain all vitally affect the viscoelastic properties of the ethanolamine gel systems. In the frequency sweep experiment, the ethanolamine gels to which agarose, agarose + PVP, and agarose + SiO2 were added behave like linear frequency-dependent viscoelastic liquids, whereas the ethanolamine gel to which PVP + SiO2 was added behaves like a nearly frequency-independent viscoelastic solid. The variation in the tan δ of these gelled propellants as a function of frequency is also discussed.

  2. Koedam {beta} factors revisited

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, J.E. [Physics Department, University of Wisconsin, Madison, WI (United States); Doughty, D.A. [Perkin-Elmer Optoelectronics, Santa Clara, CA (United States); Lister, G.G. [OSRAM SYLVANIA Inc., Beverly, MA (United States)

    2002-07-21

    A Koedam {beta} factor makes it possible to compute the total output power in line radiation from a positive column discharge using a single radiance measurement normal to an aperture in the wall. The results of analytic derivations of {beta} factors are presented for columns with uniform ({beta}=1.0) and parabolic ({beta}=0.75) excitation rates per unit volume and with negligible opacity. A Monte Carlo code for simulating radiation trapping with a spatially uniform density of absorbing atoms is then used to determine {beta} factors as a function of opacity. The code includes partial frequency redistribution and a Voigt line shape with radiative broadening, resonance collisional broadening, and Doppler broadening. The resulting {beta} factors are found to be nearly independent of opacity over a wide range of column radii for spectral line shapes dominated by Doppler broadening or by resonance collisional broadening. Additional Monte Carlo simulations are used to study {beta} factors as a function of a non-uniform density of absorbing atoms from radial cataphoresis with line shapes dominated by Doppler broadening, foreign gas broadening, and resonance collisional broadening. Radial cataphoresis is found to increase {beta} factors in all cases. Geometrical effects, refraction, and imperfect transmission at the glass wall are studied and found to decrease {beta} factors. (author)

  3. Beta-energy averaging and beta spectra

    International Nuclear Information System (INIS)

    A simple yet highly accurate method for approximately calculating spectrum-averaged beta energies and beta spectra for radioactive nuclei is presented. This method should prove useful for users who wish to obtain accurate answers without complicated calculations of Fermi functions, complex gamma functions, and time-consuming numerical integrations as required by the more exact theoretical expressions. Therefore, this method should be a good time-saving alternative for investigators who need to make calculations involving large numbers of nuclei (e.g., fission products) as well as for occasional users interested in restricted number of nuclides. The average beta-energy values calculated by this method differ from those calculated by ''exact'' methods by no more than 1 percent for nuclides with atomic numbers in the 20 to 100 range and which emit betas of energies up to approximately 8 MeV. These include all fission products and the actinides. The beta-energy spectra calculated by the present method are also of the same quality

  4. Simplified Burn-Rate Model for CMDB Propellants

    Directory of Open Access Journals (Sweden)

    A. R. Kulkarni

    1990-07-01

    Full Text Available A single model has been proposed to predict the burning rates of bimodal AP,RDX and aluminum containing CMDB propellants. This is done in terms of the respective physical constants on the basis of a recently developed model of combustion of CMDB propellants. The study has been carried out to examine the effects of changes in propellants composition, AP particle size and pressures on burning rate. Computer programs were developed for this purpose and the results obtained for typical sets of input data have been presented and compared with the actual results.

  5. Performance Evaluation and Experimental Studies on Metallised Gel Propellants

    OpenAIRE

    T. L. Varghese; N. Prabhakaran; K. P. Thanki; Subramanian, S.; Rao, S. S.; Ninan, K.N.; Krishnamurthy, V N

    1999-01-01

    Metallised gel propellants offer higher specific impulse and volumetric loading, reduced vaporisation loss, spillage and slosh problems and easy storage in comparison to the conventional liquid propellants. Theoretical performance analysis of gel propellant containing Al in unsymmetrical dimethyl hydrazine-dinitrogen tetroxide (UDMH-N/sub 2/O/sub 4} system shows peak Isp (vacuum condition) of 316.7 s and 318.3 s at oxidiser/fuel (O/f) ratios of 1.5 and 1.0, respectively for 30 per cent and 40...

  6. Combustion wave structure of ADN based composite propellant

    OpenAIRE

    Fujisato, Koji; Habu, Hiroto; Hori, Keiichi; Shibamoto, Hidefumi; Yu, Xiuchao; Miyake, Atsumi

    2013-01-01

    Combustion characteristics of pelletized ammonium dinitramide (ADN) and ADN-based propellants have been studied. Micron-meter-sized particles of Al, Fe2O3, TiO2, NiO, Cu(OH)NO3, Cu and CuO, and nano-meter-sized Al (Alex) and CuO (nanoCuO) were employed as the additives for pelletized ADN. Only nanoCuO and Alex show the remarkable effects, so they are also added to ADN-based propellant. The binder of ADN-based propellant is thermoplastic elastomer (TP), and three kinds of mixtures (TP:ADN = 30...

  7. The Damage Law of HTPB Propellant under Thermomechanical Loading

    Science.gov (United States)

    Liu, Cheng-wu; Yang, Jian-hong; Wang, Xian-meng; Ma, Yong-kang

    2016-01-01

    By way of measuring the acoustic emission (AE) signals of Hydroxyl-terminated polybutadiene (HTPB) propellant in condition of uniform speed, and combined with the scanning electron microscopy (SEM) fracture surface observation, the damage law of HTPB composite solid propellant under thermomechanical loading was studied. The results show that the effects of thermomechanical loading on HTPB propellant are related to the time and can be divided into three different stages. In the first stage, thermal air aging dominates; in the second stage, interface damage is dominant; and in the third stage, thermal air aging is once again dominant.

  8. Experimental Validation of a Marine Propeller Thrust Estimation Scheme

    Directory of Open Access Journals (Sweden)

    Luca Pivano

    2007-10-01

    Full Text Available A thrust estimation scheme for a marine propeller has been experimentally tested in waves and with a device that simulates the influence of a vessel hull. The scheme is formed by a nonlinear propeller torque observer and a mapping to generate the thrust from the observed torque. The mapping includes the estimation of the advance number. This is utilized to improve the performance when the propeller is lightly loaded. The advance speed is assumed to be unknown, and only measurements of shaft speed and motor torque have been used. Accurate results have been obtained in experimental tests.

  9. Prevention of Dealloying in Manganese Aluminium Bronze Propeller: Part II

    Directory of Open Access Journals (Sweden)

    Napachat Tareelap

    2014-03-01

    Full Text Available Due to the failure of manganese aluminium bronze (MAB propeller caused by dealloying corrosion as described in Part I [1], this work aims to study the prevention of dealloying corrosion using aluminium and zinc sacrificial anodes. The results indicated that both of the sacrificial anodes could prevent the propeller from dealloying. Moreover, the dealloying in seawater was less than that found in brackish water. It was possible that hydroxide ions, from cathodic reaction, reacted with calcium in seawater to form calcium carbonate film protecting the propeller from corrosion.

  10. Improvements on computations of high speed propeller unsteady aerodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bousquet, J.M.; Gardarein, P. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)

    2003-09-01

    This paper presents the application of the CANARI flow solver to the computation of unsteady effects in the aerodynamic interaction of a high speed propeller with the aircraft. The method is first validated on the APIAN isolated propeller test case by comparison with experiment at M = 0.7. The method is then applied to the time accurate 3D Euler computation of a generic transport aircraft at M = 0.68. Analysis of the results shows significant unsteady effects both on the propeller forces and on the wing aerodynamic flows, by comparison with steady computations. (authors)

  11. β-Propeller Blades as Ancestral Peptides in Protein Evolution

    OpenAIRE

    Kopec, Klaus O.; Lupas, Andrei N.

    2013-01-01

    Proteins of the β-propeller fold are ubiquitous in nature and widely used as structural scaffolds for ligand binding and enzymatic activity. This fold comprises between four and twelve four-stranded β-meanders, the so called blades that are arranged circularly around a central funnel-shaped pore. Despite the large size range of β-propellers, their blades frequently show sequence similarity indicative of a common ancestry and it has been proposed that the majority of β-propellers arose diverge...

  12. Effects of Nano-Aluminium on The Combustion of A PolyNIMMO-Based Propellant

    Institute of Scientific and Technical Information of China (English)

    Clive Woodley; Peter Henning

    2014-01-01

    Propellants containing micro-aluminium particles have been shown to produce faster burn rates than conventional gun propellants.However,they are also more abrasive than conventional propellants.Nano-material propellants have been reported to give similar benefits to micron-material propellants but without the disadvantage of increased abrasion.Tests were conducted to compare the burn rates,ignitability and wear rates of a propellant loaded with 0% aluminium,15% micro-aluminium and 15%nano-aluminium.Closed vessel tests showed a burn rate increase of 39% in the range 30-250 MPa,and 70% at low pressure (50-100 MPa)for the nano-aluminium propellant compared with the baseline propellant.The micro-aluminium propellant showed only a 10% increase in the burn rate compared with the standard propellant.The ignition delay for the nano-aluminium propellant was slightly shorter than that of the baseline propellant.Substantially increased wear rates were measured for the micro-aluminium propellant.The nano-aluminium propellant showed reduced wear rates compared with the micro-aluminium propellant but these were still substantially greater than those for the baseline propellant.

  13. Double beta decay experiments

    OpenAIRE

    Barabash, A. S.

    2011-01-01

    The present status of double beta decay experiments is reviewed. The results of the most sensitive experiments are discussed. Proposals for future double beta decay experiments with a sensitivity to the $$ at the level of (0.01--0.1) eV are considered.

  14. Negative Beta Encoder

    CERN Document Server

    Kohda, Tohru; Aihara, Kazuyuki

    2008-01-01

    A new class of analog-digital (A/D), digital-analog (D/A) converters as an alternative to conventional ones, called $\\beta$-encoder, has been shown to have exponential accuracy in the bit rates while possessing self-correction property for fluctuations of amplifier factor $\\beta$ and quantizer threshold $\

  15. Betting against Beta

    DEFF Research Database (Denmark)

    Frazzini, Andrea; Heje Pedersen, Lasse

    2014-01-01

    We present a model with leverage and margin constraints that vary across investors and time. We find evidence consistent with each of the model's five central predictions: (1) Because constrained investors bid up high-beta assets, high beta is associated with low alpha, as we find empirically for...

  16. Gun barrel erosion - Comparison of conventional and LOVA gun propellants

    NARCIS (Netherlands)

    Hordijk, A.C.; Leurs, O.

    2006-01-01

    The research department Energetic Materials within TNO Defence, Security and Safety is involved in the development and (safety and insensitive munitions) testing of conventional (nitro cellulose based) and thermoplastic elastomer (TPE) based gun propellants. Recently our testing capabilities have be

  17. Simulated propeller slipstream effects on a supercritical wing

    Science.gov (United States)

    Welge, H. R.; Crowder, J. P.

    1978-01-01

    To quantify the installed performance of high speed (M = 0.8) turboprop propulsion systems, an experimental program designed to assess the magnitude of the aerodynamic interference of a propeller slipstream on a supercritical wing has been conducted. The test was conducted in the NASA Ames 14-foot wind tunnel. An ejector-nacelle propeller slipstream simulator was used to produce a slipstream with characteristics typical of advanced propellers presently being investigated. A supercritical wing-body configuration was used to evaluate the interference effects. A traversing total pressure rake was used to make flow field measurements behind the wing and to calibrate the slipstream simulator. The force results indicated that the interference drag amounted to an increase of ten counts or about 3% of the wing-body drag for a two engine configuration at the nominal propeller operating conditions. However, at the higher swirl angles (11 deg vs. 7 deg nominally) the interference drag was favorable by about the same magnitude.

  18. Propellant Flow Actuated Piezoelectric Rocket Engine Igniter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spark ignition of a bi-propellant rocket engine is a classic, proven, and generally reliable process. However, timing can be critical, and the control logic,...

  19. Model-based Diagnostics for Propellant Loading Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — The loading of spacecraft propellants is a complex, risky operation. Therefore, diagnostic solutions are neces- sary to quickly identify when a fault occurs, so...

  20. Modified Collins Cryocooler for Cryo-Propellant Thermal Management Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future lunar and planetary explorations will require the storage of cryogenic propellants, particularly liquid oxygen (LOX) and liquid hydrogen (LH2), in low earth...

  1. Advanced Insulation Materials for Cryogenic Propellant Storage Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Materials Technology, Inc (AMTI) responds to the Topic X9 entitled [HTML_REMOVED]Propulsion and Propellant Storage[HTML_REMOVED] under subtopic X9.01,...

  2. Self-Propelled Hovercraft Based on Cold Leidenfrost Phenomenon.

    Science.gov (United States)

    Shi, Meng; Ji, Xing; Feng, Shangsheng; Yang, Qingzhen; Lu, Tian Jian; Xu, Feng

    2016-01-01

    The Leidenfrost phenomenon of liquid droplets levitating and dancing when placed upon a hot plate due to propulsion of evaporative vapor has been extended to many self-propelled circumstances. However, such self-propelled Leidenfrost devices commonly need a high temperature for evaporation and a structured solid substrate for directional movements. Here we observed a "cold Leidenfrost phenomenon" when placing a dry ice device on the surface of room temperature water, based on which we developed a controllable self-propelled dry ice hovercraft. Due to the sublimated vapor, the hovercraft could float on water and move in a programmable manner through designed structures. As demonstrations, we showed that the hovercraft could be used as a cargo ship or a petroleum contamination collector without consuming external power. This phenomenon enables a novel way to utilize programmable self-propelled devices on top of room temperature water, holding great potential for applications in energy, chemical engineering and biology. PMID:27338595

  3. Propellant Flow Actuated Piezoelectric Rocket Engine Igniter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Under a Phase 1 effort, IES successfully developed and demonstrated a spark ignition concept where propellant flow drives a very simple fluid mechanical oscillator...

  4. Nano-aluminum as energetic material for rocket propellants

    Energy Technology Data Exchange (ETDEWEB)

    Meda, L. [Istituto G. Donegani, Polimeri Europa, 28100 Novara (Italy)], E-mail: laura.meda@polimerieuropa.com; Marra, G. [Istituto G. Donegani, Polimeri Europa, 28100 Novara (Italy); Galfetti, L.; Severini, F.; De Luca, L. [Politecnico di Milano, Solid Propulsion Laboratory (SP Lab), 20158 Milano (Italy)

    2007-09-15

    A characterization of differently sized aluminum powders, by using BET (specific surface measurements), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS), was performed in order to evaluate their performance in solid propellant. These aluminum powders were used in manufacturing composite rocket propellants, that are based on Ammonium Perchlorate (AP) as oxidizer and Hydroxyl-Terminated-PolyButadiene (HTPB) as binder. The reference formulation was AP/HTPB/Al with 68/17/15 mass fractions, respectively. The ballistic characterization of studied propellants, made in terms of steady burning rates, showed how better is the performance of nano-aluminized compared to micro-aluminized propellants. Measurements of Al powder ignition time and temperature were also carried out.

  5. Optimum Disposition of Metal Particles in the Propellant Grain

    Directory of Open Access Journals (Sweden)

    Leonid L. Minkov

    2014-01-01

    Full Text Available Using the dispersed metal in solid propellants to increase the temperature of combustion products leads to such a problem as the specific impulse loss due to the incomplete combustion of metal particles in the exhaust products. A redistribution of metal loaded into the propellant grain is one of the methods to decrease the specific impulse loss. This paper reports on the ways to obtain the optimum metal particle disposition for the case-bounded propellant grain of tube cross-sectional type. Three different approaches to analyze the metal combustion efficiency are discussed. The influence of the dynamic nonequilibrium of two-phase flow on the optimum metal particles disposition in the propellant grain of tube cross-sectional type is investigated.

  6. Effect of the number of blades on propeller wake evolution

    Energy Technology Data Exchange (ETDEWEB)

    Felli, Mario; Guj, Giulio; Camussi, Roberto [University, Department of Mechanical and Industrial Engineering, Rome (Italy)

    2008-03-15

    The effect of the number of blades on wake evolution was investigated on three propellers having the same blade geometry but different numbers of blades. The experiments concerned velocity measurements along nine transversal planes of the wake by LDV phase-sampling techniques. The study was performed with all the propellers having the same tip vortex intensity. In addition, high-speed visualizations were carried out to analyze the main features of propeller wake evolution in the transition and in the far wake. Aspects concerning wake evolution were pointed out, with particular emphasis on the instability mechanism of the propeller slipstream and on its correlation with the blade-to-blade interaction phenomenon. (orig.)

  7. Propeller Flaps: A Review of Indications, Technique, and Results

    Science.gov (United States)

    D'Arpa, Salvatore; Toia, Francesca; Pirrello, Roberto; Moschella, Francesco; Cordova, Adriana

    2014-01-01

    In the last years, propeller flaps have become an appealing option for coverage of a large range of defects. Besides having a more reliable vascular pedicle than traditional flap, propeller flaps allow for great freedom in design and for wide mobilization that extend the possibility of reconstructing difficult wounds with local tissues and minimal donor-site morbidity. They also allow one-stage reconstruction of defects that usually require multiple procedures. Harvesting of a propeller flap requires accurate patient selection, preoperative planning, and dissection technique. Complication rate can be kept low, provided that potential problems are prevented, promptly recognized, and adequately treated. This paper reviews current knowledge on propeller flaps. Definition, classification, and indications in the different body regions are discussed based on a review of the literature and on the authors' experience. Details about surgical technique are provided, together with tips to avoid and manage complications. PMID:24971367

  8. Numerical Simulation of Viscous Cavitating Flow Around A Ship Propeller

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhi-feng; FANG Shi-liang; WANG Xiao-yan; MENG Zhao-wen; LIU Ping-xiang; DU Xuan-min

    2011-01-01

    In the present study,cavitation and a ship propeller wake are reported by computed fluid dynamics based on viscous multiphase flow theory.Some recent validation results with a hybrid grid based on unsteady Navier-Stokes (N-S) and bubble dynamics equations are presented to predict velocity,pressure and vapor volume fraction in propeller wake in a uniform inflow.Numerical predictions of sheet cavitation,tip vortex cavitation and hub vortex cavitation are in agreement with the experimental data,same as numerical predictions of longitudinal and transversal evolution of the axial velocity.Blade and shaft rate frequency of propeller is well predicted by the computed results of pressure,and tip vortex is the most important to generate the pressure field within the near wake.The overall results indicate that the present approach is reliable for prediction of cavitation and propeller wake on the condition of uniform inflow.

  9. Numerical Prediction of Hydromechanical Behaviour of Controllable Pitch Propeller

    Directory of Open Access Journals (Sweden)

    Saman Tarbiat

    2014-01-01

    Full Text Available The research described in this paper was carried out to predict hydrodynamic and frictional forces of controllable pitch propeller (CPP that bring about fretting problems in a blade bearing. The governing equations are Reynolds-averaged Navier-Stokes (RANS and are solved by OpenFOAM solver for hydrodynamic forces behind the ship’s wake. Frictional forces are calculated by practical mechanical formulae. Different advance velocities with constant rotational speed for blades are used to achieve hydrodynamic coefficients in open water and the wake behind the propeller. Results are compared at four different pitches. Detailed numerical results of 3D modelling of the propeller, hydrodynamic characteristics, and probability of the fretting motion in the propeller are presented. Results show that the probability of the fretting movement is related to the pitch.

  10. NUMERICAL RESEARCHES ON INTERACTION BETWEEN PROPELLERS IN UNIFORM FLOW

    Institute of Scientific and Technical Information of China (English)

    FENG Xue-mei; LU Chuan-jing; WU Qiong; CAI Rong-quan

    2012-01-01

    Numerical simulations of the flow around two bidirectional staggered propellers are conducted in uniform flow.The computed open water performance of the fore-propeller is compared with the corresponding experimental results,and the influence of the fore-propeller on the aft one is carefully investigated.It is found that the inflow around the aft propeller close to the side of the fore is especially affected by the fore one,leading to abnormal circumferential distribution of force on the blade in the shade region.For either forces or velocity distributions,the abnormal changes behave contrarily for cases with the rotating speed larger or smaller than the idle.Moreover,the more the rotating speed of the fore differs from the idle,the larger the abnormal values become.

  11. Propeller Flaps: A Review of Indications, Technique, and Results

    Directory of Open Access Journals (Sweden)

    Salvatore D'Arpa

    2014-01-01

    Full Text Available In the last years, propeller flaps have become an appealing option for coverage of a large range of defects. Besides having a more reliable vascular pedicle than traditional flap, propeller flaps allow for great freedom in design and for wide mobilization that extend the possibility of reconstructing difficult wounds with local tissues and minimal donor-site morbidity. They also allow one-stage reconstruction of defects that usually require multiple procedures. Harvesting of a propeller flap requires accurate patient selection, preoperative planning, and dissection technique. Complication rate can be kept low, provided that potential problems are prevented, promptly recognized, and adequately treated. This paper reviews current knowledge on propeller flaps. Definition, classification, and indications in the different body regions are discussed based on a review of the literature and on the authors’ experience. Details about surgical technique are provided, together with tips to avoid and manage complications.

  12. Evaluation of propeller/nacelle interactions in the PTA program

    Science.gov (United States)

    Aljabri, A. S.; Lyman, V.; Parker, R. J.

    1986-01-01

    Advanced highly-loaded propellers are proposed to power transport aircraft that cruise at high subsonic speeds giving significant fuel savings over the equivalent turbofan engine. In order to realize these savings, the propeller must be installed so that the aerodynamics of the propeller/nacelle combination do not lead to excessive cyclic blade stresses or installation losses. The on-going, NASA sponsored, Propfan Test Assessment Program (PTA) has provided the first high-speed wind-tunnel data on an installed propfan complete with an inlet. This paper presents computational techniques that allow: (1) optimization of inlet plane location, (2) contouring of lip and cowl, and (3) estimation of propeller cyclic loads due to a nonuniform flowfield. These computational methods, in spite of the complexity of the configuration and the slipstream effects, provide predictions of aerodynamic performance which are in excellent agreement with wind-tunnel data.

  13. Spacecraft Spin Rate Change due to Propellant Redistribution Between Tanks

    Science.gov (United States)

    Choi, Kyu Hong

    1984-09-01

    A bubble trapped in the liquid manifold of INTELSAT IV F-7 spacecraft caused a mass imbalance between the System 1 propellant tanks and a wobble half angle of 0.38 degree to 0.48 degree. A maneuver in May 14, 1980 passed the bubble through the axial jet and allowed propellant to redistribute. A 0.2 rpm change in spin rate was observed with an exponential decay time constant of 6 minutes. In this paper, moment of inertia, tank geometry and hydrodynamics models are derived to match the observed spin rate data. The values of the total mass of the propellant considered were 16, 19 and 20 Kgs with corresponding mass imbalances of 14.3, 15 and 15.1 Kgs, respectively. The result shows excellent agreement with observed spin rate data but it was necessary to assume a greater mass of hydrazine in the tanks than propellant accounting indicated.

  14. Dynamical Model of Rocket Propellant Loading with Liquid Hydrogen

    Data.gov (United States)

    National Aeronautics and Space Administration — A dynamical model describing the multi-stage process of rocket propellant loading has been developed. It accounts for both the nominal and faulty regimes of...

  15. Atmospheric Processing Module for Mars Propellant Production

    Science.gov (United States)

    Muscatello, A.; Devor, R.; Captain, J.

    2014-01-01

    The multi-NASA center Mars Atmosphere and Regolith COllector/PrOcessor for Lander Operations (MARCO POLO) project was established to build and demonstrate a methaneoxygen propellant production system in a Mars analog environment. Work at the Kennedy Space Center (KSC) Applied Chemistry Laboratory is focused on the Atmospheric Processing Module (APM). The purpose of the APM is to freeze carbon dioxide from a simulated Martian atmosphere containing the minor components nitrogen, argon, carbon monoxide, and water vapor at Martian pressures (approx. 8 torr) by using dual cryocoolers with alternating cycles of freezing and sublimation. The resulting pressurized CO(sub 2) is fed to a methanation subsystem where it is catalytically combined with hydrogen in a Sabatier reactor supplied by the Johnson Space Center (JSC) to make methane and water vapor. We first used a simplified once-through setup and later employed a H(sub 2)CO(sub 2) recycling system to improve process efficiency. This presentation and paper will cover (1) the design and selection of major hardware items, such as the cryocoolers, pumps, tanks, chillers, and membrane separators, (2) the determination of the optimal cold head design and flow rates needed to meet the collection requirement of 88 g CO(sub 2) hr for 14 hr, (3) the testing of the CO(sub 2) freezer subsystem, and (4) the integration and testing of the two subsystems to verify the desired production rate of 31.7 g CH(sub 4) hr and 71.3 g H(sub 2)O hr along with verification of their purity. The resulting 2.22 kg of CH(sub 2)O(sub 2) propellant per 14 hr day (including O(sub 2) from electrolysis of water recovered from regolith, which also supplies the H(sub 2) for methanation) is of the scale needed for a Mars Sample Return mission. In addition, the significance of the project to NASAs new Mars exploration plans will be discussed.

  16. Rapid synthesis of beta zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Wei; Chang, Chun -Chih; Dornath, Paul; Wang, Zhuopeng

    2015-08-18

    The invention provides methods for rapidly synthesizing heteroatom containing zeolites including Sn-Beta, Si-Beta, Ti-Beta, Zr-Beta and Fe-Beta. The methods for synthesizing heteroatom zeolites include using well-crystalline zeolite crystals as seeds and using a fluoride-free, caustic medium in a seeded dry-gel conversion method. The Beta zeolite catalysts made by the methods of the invention catalyze both isomerization and dehydration reactions.

  17. Deconsolidation and combustion performance of thermally consolidated propellants deterred by multi-layers coating

    OpenAIRE

    Zheng-gang Xiao; San-jiu Ying; Fu-ming Xu

    2014-01-01

    Both heating and solvent-spray methods are used to consolidate the standard grains of double-base oblate sphere propellants plasticized with triethyleneglycol dinitrate (TEGDN) (TEGDN propellants) to high density propellants. The obtained consolidated propellants are deterred and coated with the slow burning multi-layer coating. The maximum compaction density of deterred and coated consolidated propellants can reach up to 1.39 g/cm3. Their mechanic, deconsolidation and combustion performances...

  18. The fine structure constant alpha: relevant for a model of a self-propelling photon and for particle masses

    Science.gov (United States)

    Greulich, Karl O.

    2015-09-01

    A model for a self propelling (i.e. massless) photon1 is based on oscillations of a pair of charges amounting to elementary charge divided by SQRT alpha, where alpha is the fine structure (Sommerfeld) constant. When one assumes a similar model for particles that do have rest mas (i.e. which are non- self propelling), alpha plays also a role in the rest masses of elementary particles. Indeed all fundamental elementary particle masses can be described by the alpha / beta rule2 --> m(particle) = alpha-n * betam* 27.2 eV /c2 where beta is the proton to electron mass ratio 183612 and n= 0….14, m= -1,0 or Thus, photons and particle masses are intimately related to the fine structure constant. If the latter would not have been strictly constant throughout all times, this would have had consequences for the nature of light and for all masses including those of elementary particles.

  19. In-space propellant logistics. Volume 1: Executive summary

    Science.gov (United States)

    1972-01-01

    The study addresses the systems and operational problems associated with the transport, transfer, and storage of cryogenic propellants in low earth orbits. The safety problems connected with in-space propellant logistics operations are also considered.Correlation between the two projects was maintained by including safety considerations, resulting from the system safety analysis, in the trade studies and evaluations of alternate operating concepts in the systems operations analysis.

  20. Circular Motion of Asymmetric Self-Propelling Particles

    Science.gov (United States)

    Kümmel, Felix; ten Hagen, Borge; Wittkowski, Raphael; Buttinoni, Ivo; Eichhorn, Ralf; Volpe, Giovanni; Löwen, Hartmut; Bechinger, Clemens

    2013-05-01

    Micron-sized self-propelled (active) particles can be considered as model systems for characterizing more complex biological organisms like swimming bacteria or motile cells. We produce asymmetric microswimmers by soft lithography and study their circular motion on a substrate and near channel boundaries. Our experimental observations are in full agreement with a theory of Brownian dynamics for asymmetric self-propelled particles, which couples their translational and orientational motion.

  1. Validity of Fluctuation Theorem on Self-Propelling Particles

    OpenAIRE

    Suzuki, R.; Jiang, H.R.; Sano, M.

    2011-01-01

    The experimental application of fluctuation theorem (FT) on nanometer to submicrometer sized systems has received thorough attention in the past several years. Nonetheless, the employment of FT on self-propelling objects has seldom been performed due to experimental difficulties. In this paper, we applied FT on a doublet that is comprised of asymmetrically coated self-propelling colloidal particles (Janus particles), which experiences a continuous rotation by applying AC electric field. We fo...

  2. A Semi-Automatic Thickness Inspection Technique for Marine Propellers

    Institute of Scientific and Technical Information of China (English)

    M; K; Lam; S; F; Lee; C; S; Lam; W; S; Chow; P; Iovenitti; S; H; Masood

    2002-01-01

    This paper describes the design and development of a Semi-Automatic Precision Caliper System to measure the thickness of an outboard marine engine propeller blade. Several commonly used methods for measuring the thickness of a propeller blade are reviewed in this paper. These include the P rops Scan, 3D Vision System and Black Dog. However, the operating practices and availability of different facilities in industry necessitate a more cost-effect ive approach. An alternative method using a Semi-Auto...

  3. Self-propelled rod-like swimmers near surfaces

    OpenAIRE

    Marx, Kristian

    2011-01-01

    Self-propelled microswimmers are biological organisms or synthetic objects that propel themselves through the surrounding fluid. Examples are sperm, various swimming bacteria such as Escherichia coli, the green alga Chlamydomonas reinhardtii and artificial bimetallic rods that catalyze chemical reactions in the surrounding hydrogen peroxide. Even though these swimmers differ in their size and driving mechanism, they can be classified as having pusher or puller polarity, which means that th...

  4. Swarm behavior of self-propelled rods and swimming flagella

    OpenAIRE

    Yang, Y; Marceau, V.; Gompper, G.

    2010-01-01

    Systems of self-propelled particles are known for their tendency to aggregate and to display swarm behavior. We investigate two model systems, self-propelled rods interacting via volume exclusion, and sinusoidally-beating flagella embedded in a fluid with hydrodynamic interactions. In the flagella system, beating frequencies are Gaussian distributed with a non-zero average. These systems are studied by Brownian-dynamics simulations and by mesoscale hydrodynamics simulations, respectively. The...

  5. A molecular propeller effect for chiral separation and analysis

    OpenAIRE

    Clemens, Jonathon B.; Kibar, Osman; Chachisvilis, Mirianas

    2015-01-01

    Enantiomers share nearly identical physical properties but have different chiral geometries, making their identification and separation difficult. Here we show that when exposed to a rotating electric field, the left- and right-handed chiral molecules rotate with the field and act as microscopic propellers; moreover, owing to their opposite handedness, they propel along the axis of field rotation in opposite directions. We introduce a new molecular parameter called hydrodynamic chirality to c...

  6. Hydroacoustic characterization of a marine propeller through the Acoustic Analogy

    OpenAIRE

    Ianniello, Sandro; Muscari, Roberto; Di Mascio, Andrea

    2011-01-01

    This paper deals with the use of the Acoustic Analogy for the prediction of the underwater noise generated by a marine propeller. Different configurations are treated in order to demonstrate the potentiality of such a numerical approach and to analyze the role played by the different noise sources. Unlike analogous aeronautical propellers, it will be shown that the evaluation of the nonlinear quadrupole sources is relevant regardless of the blade rotational speed. On the contrary, the linear ...

  7. Viscous-Inviscid Coupling Methods for Advanced Marine Propeller Applications

    OpenAIRE

    Martin Greve; Katja Wöckner-Kluwe; Moustafa Abdel-Maksoud; Thomas Rung

    2012-01-01

    The paper reports the development of coupling strategies between an inviscid direct panel method and a viscous RANS method and their application to complex propeller ows. The work is motivated by the prohibitive computational cost associated to unsteady viscous flow simulations using geometrically resolved propellers to analyse the dynamics of ships in seaways. The present effort aims to combine the advantages of the two baseline methods in order to reduce the numerical effort without comprom...

  8. β-Propeller blades as ancestral peptides in protein evolution.

    Directory of Open Access Journals (Sweden)

    Klaus O Kopec

    Full Text Available Proteins of the β-propeller fold are ubiquitous in nature and widely used as structural scaffolds for ligand binding and enzymatic activity. This fold comprises between four and twelve four-stranded β-meanders, the so called blades that are arranged circularly around a central funnel-shaped pore. Despite the large size range of β-propellers, their blades frequently show sequence similarity indicative of a common ancestry and it has been proposed that the majority of β-propellers arose divergently by amplification and diversification of an ancestral blade. Given the structural versatility of β-propellers and the hypothesis that the first folded proteins evolved from a simpler set of peptides, we investigated whether this blade may have given rise to other folds as well. Using sequence comparisons, we identified proteins of four other folds as potential homologs of β-propellers: the luminal domain of inositol-requiring enzyme 1 (IRE1-LD, type II β-prisms, β-pinwheels, and WW domains. Because, with increasing evolutionary distance and decreasing sequence length, the statistical significance of sequence comparisons becomes progressively harder to distinguish from the background of convergent similarities, we complemented our analyses with a new method that evaluates possible homology based on the correlation between sequence and structure similarity. Our results indicate a homologous relationship of IRE1-LD and type II β-prisms with β-propellers, and an analogous one for β-pinwheels and WW domains. Whereas IRE1-LD most likely originated by fold-changing mutations from a fully formed PQQ motif β-propeller, type II β-prisms originated by amplification and differentiation of a single blade, possibly also of the PQQ type. We conclude that both β-propellers and type II β-prisms arose by independent amplification of a blade-sized fragment, which represents a remnant of an ancient peptide world.

  9. Prevention of Dealloying in Manganese Aluminium Bronze Propeller: Part II

    OpenAIRE

    Napachat Tareelap; Kaysinee Sriraksasin; Nakorn Srisukhumbowornchai; Swieng Thuanboon; Choochat Nitipanyawong

    2014-01-01

    Due to the failure of manganese aluminium bronze (MAB) propeller caused by dealloying corrosion as described in Part I [1], this work aims to study the prevention of dealloying corrosion using aluminium and zinc sacrificial anodes. The results indicated that both of the sacrificial anodes could prevent the propeller from dealloying. Moreover, the dealloying in seawater was less than that found in brackish water. It was possible that hydroxide ions, from cathodic reaction, reacted with calcium...

  10. Prediction of propeller-induced hull-pressure fluctuations

    OpenAIRE

    Van Wijngaarden, H.C.J.

    2011-01-01

    The cavitating propeller often forms the primary source of noise and vibration on board ships. The propeller induces hydroacoustic pressure fluctuations due to the passing blades and, more importantly, the dynamic activity of cavities in the propeller’s immediate vicinity. The accurate prediction of the resulting vibratory hull-excitation forces is indispensible in the ship design process, but is not always warranted. From this follows the main objective of the thesis, which is the developmen...

  11. β-Propeller Blades as Ancestral Peptides in Protein Evolution

    Science.gov (United States)

    Kopec, Klaus O.; Lupas, Andrei N.

    2013-01-01

    Proteins of the β-propeller fold are ubiquitous in nature and widely used as structural scaffolds for ligand binding and enzymatic activity. This fold comprises between four and twelve four-stranded β-meanders, the so called blades that are arranged circularly around a central funnel-shaped pore. Despite the large size range of β-propellers, their blades frequently show sequence similarity indicative of a common ancestry and it has been proposed that the majority of β-propellers arose divergently by amplification and diversification of an ancestral blade. Given the structural versatility of β-propellers and the hypothesis that the first folded proteins evolved from a simpler set of peptides, we investigated whether this blade may have given rise to other folds as well. Using sequence comparisons, we identified proteins of four other folds as potential homologs of β-propellers: the luminal domain of inositol-requiring enzyme 1 (IRE1-LD), type II β-prisms, β-pinwheels, and WW domains. Because, with increasing evolutionary distance and decreasing sequence length, the statistical significance of sequence comparisons becomes progressively harder to distinguish from the background of convergent similarities, we complemented our analyses with a new method that evaluates possible homology based on the correlation between sequence and structure similarity. Our results indicate a homologous relationship of IRE1-LD and type II β-prisms with β-propellers, and an analogous one for β-pinwheels and WW domains. Whereas IRE1-LD most likely originated by fold-changing mutations from a fully formed PQQ motif β-propeller, type II β-prisms originated by amplification and differentiation of a single blade, possibly also of the PQQ type. We conclude that both β-propellers and type II β-prisms arose by independent amplification of a blade-sized fragment, which represents a remnant of an ancient peptide world. PMID:24143202

  12. Use of acoustic analogy for marine propeller noise characterisation

    OpenAIRE

    Lidtke, Artur; Turnock, Stephen; Humphrey, Victor

    2015-01-01

    Being able to predict shipborne noise is of significant importance to international maritime community. Porous Ffowcs-Williams Hawkings acoustic analogy is used with cavitation model by Sauer & Schnerr in order to predict the noise signature of the Potsdam Propeller operating in open water. The radiation pattern is shown to be predominantly affected by a dipole source, in addition to less prominent sources at the propeller plane and in the wake. It is shown that the predicted sound pressure l...

  13. Ducted propeller performance analysis using a boundary element model

    OpenAIRE

    Salvatore, Francesco; Calcagni, Danilo; Greco, Luca

    2006-01-01

    This report describes the computational analysis of the unviscid flow around a ducted propeller using a BEM model. The activity is performed in the framework of a research program co-funded by the European Union under the "SUPERPROP" Project TST4-CT-2005-516219. The theoretical and computational methodology is described and results of a validation excercise on several test cases is presented and discussed. In particular, the proposed formulation is applied to the analysis of ducted propellers...

  14. Optimal preliminary propeller design using nonlinear constrained mathematical programming technique

    OpenAIRE

    Radojčić, D.

    1985-01-01

    Presented is a nonlinear constrained optimization technique applied to optimal propeller design at the preliminary design stage. The optimization method used is Sequential Unconstrained Minimization Technique - SUMT, which can treat equality and inequality, or only inequality constraints. Both approaches are shown. Application is given for Wageningen B-series and Gawn series propellers. The problem is solved on an Apple II microcomputer. One of the advantages of treating the constrained ...

  15. Optimization of propeller pitch and revolutions in behind condition

    OpenAIRE

    Hasfjord, Steffen

    2014-01-01

    To reduce costs and limit pollution from transportation of goods by sea, a method for optimization of the propulsive efficiency of an 8000 dead weight tonnage tanker is investigated. Emphasis is put on the interaction between the propulsion system and the hull.The optimum combination of pitch and propeller rate of revolutions is sought for a controllable pitch propeller, working behind a tanker. Two stern shapes have been examined at the vessel’s design speed, and in bollard pull conditi...

  16. Optimum propeller or windmill design in a wind gradient

    OpenAIRE

    Harada, Masashi; 原田 正志

    2004-01-01

    A method for optimizing a propeller or windmill in a wind gradient has been developed, based on the lifting-line theory. This method takes the effect of trailing vortices and shed vortices into consideration, and consists of two fundamental major concepts. The first is the description of the problem by quadratic functions. The second concept is the reduction of the number of unknown variables using the periodical characteristics of the solution. In the first concept, optimum propeller design ...

  17. PIV-based load determination in aircraft propellers

    OpenAIRE

    Ragni, D.

    2012-01-01

    The thesis describes the application of particle image velocimetry (PIV) to study the aerodynamic loads of airfoils and aircraft propellers. The experimental work focuses on the development of a measurement procedure to infer the pressure of the flow field from the velocity distribution obtained by PIV velocimetry. The technique offers important advantages in aircraft propellers, since the loads can be locally inspected without the need to install pressure sensors and momentum balances in rot...

  18. Parametric Studies on Star Port Propellant Grain For Ballistic Evaluation

    OpenAIRE

    Himanshu Shekhar

    2005-01-01

    Star port propellant grains have been extensively studied for their operating as well as geometrical parameters. It is observed that reduced tail-off and better neutrality cannot be achieved simultaneously in a configuration. Parametric study is conducted to know the effect of various parameters of star-shaped propellant grains for ballistic evaluation motor. For reduced tail-off, higher characteristic velocity, lower outer diameter of the star, and lower value of angular fraction is preferre...

  19. Numerical study of hub taper angle on podded propeller performance

    International Nuclear Information System (INIS)

    Presently, the majority of podded propulsion systems are of the pulling type, because this type provides better hydrodynamic efficiency than the pushing type. There are several possible explanations for the better overall performance of a puller type podded propulsor. One is related to the difference in hub shape. Puller and pusher propellers have opposite hub taper angles, hence different hub and blade root shape. These differences cause changes in the flow condition and possibly influence the overall performance. The current study focuses on the variation in performance of pusher and puller propellers with the same blade sections, but different hub taper angles. A hyperboloidal low order source doublet steady/unsteady time domain panel method code was modified and used to evaluate effects of hub taper angle on the open water propulsive performance of some fixed pitch screw propellers used in podded propulsion systems. The modified code was first validated against measurements of two model propellers in terms of average propulsive performance and good agreement was found. Major findings include significant effects of hub taper angle on propulsive performance of tapered hub propellers and noticeable effects of hub taper angle on sectional pressure distributions of tapered hub propeller blades. (author)

  20. Glycidyl Azide Polymer-based Enhanced Energy LOVA Gun Propellant

    Directory of Open Access Journals (Sweden)

    R. R. Sanghavi

    2006-07-01

    Full Text Available In this study, cyclotrimethylene trinitramine propellants with triacetin (TA-plasticisedcellulose acetate (CA and nitrocellulose (NC combination as binders were evaluated for lowvulnerable ammunition (LOVA. Triacetin was replaced by energetic plasticiser; glycidyl azidepolymer (GAP in increments to enhance the performance in terms of force constant . In additionto ballistics, parameters like vulnerability, mechanical and thermal properties of GAP-basedpropellants in comparison to those of TA-based propellants, were also determined. The studybrings out that the incorporation of 2-6 per cent GAP in place of TA resulted in the enhancementof force constant by 22-70 J/g and improved overall combustion characteristics. DSC revealedthat thermal decomposition of GAP-LOVA propellants evolved more energy than TA-LOVApropellants. GAP-based LOVA propellant similar to TA-plasticised LOVA propellant, was foundsuperior to NQ propellant in vulnerability tests as well as in hot fragment conductive ignition(HFCI studies. As regards mechanical properties, incorporation of GAP resulted in improvedcompression strength.

  1. Performance Evaluation and Experimental Studies on Metallised Gel Propellants

    Directory of Open Access Journals (Sweden)

    T. L. Varghese

    1999-01-01

    Full Text Available Metallised gel propellants offer higher specific impulse and volumetric loading, reduced vaporisation loss, spillage and slosh problems and easy storage in comparison to the conventional liquid propellants. Theoretical performance analysis of gel propellant containing Al in unsymmetrical dimethyl hydrazine-dinitrogen tetroxide (UDMH-N/sub 2/O/sub 4} system shows peak Isp (vacuum condition of 316.7 s and 318.3 s at oxidiser/fuel (O/f ratios of 1.5 and 1.0, respectively for 30 per cent and 40 per cent UDMH-Al gel propellants, under standard conditions. The effect of other parameters like area ratio and chamber pressure on performance has been brought out in view of mission oriented applications. Aluminium has been found to be a better choice over magnesium in metallised gel propellants. Experimental studies on UDMH gellation using propellant grade (15 micrometerand pyrotechnic grade (1.5 micrometerAl in 500g batch level show that gellant(methyl cellulose concentration could be reduced by 50 percent using pyrotechnic grade Al. The pseudoplastic-thixotropic behaviour, flow rate through die holes, burst pressure tests and bulk density are studied. UDMH -25 to 30 per cent Al gels with both grades of Al are found to be stable, pseudoplastic (shear thinning and thixotropic (time-dependent shear thinning, but their flow pattern through die holes differ in nature.

  2. Electromagnetic Pumps for Conductive-Propellant Feed Systems

    Science.gov (United States)

    Markusic, T. E.; Polzin, K. A.

    2005-01-01

    There has been a recent, renewed interest in high-power electric thrusters for application in nuclear-electric propulsion systems. Two of the most promising thrusters utilize liquid metal propellants: the lithium-fed magnetoplasmadynamic thruster and the bismuth-fed Hall thruster. An important element of part of the maturation of these thrusters will be the development of compact, reliable conductive-propellant feed system components. In the present paper we provide design considerations and experimental calibration data for electromagnetic (EM) pumps. The role of an electromagnetic pump in a liquid metal feed system is to establish a pressure gradient between the propellant reservoir and the thruster - to establish the requisite mass flow rate. While EM pumps have previously been used to a limited extent in nuclear reactor cooling loops, they have never been implemented in electric propulsion (EP) systems. The potential benefit of using EM pumps for EP are reliability (no moving parts) and the ability to precisely meter the propellant flow rate. We have constructed and tested EM pumps that use gallium, lithium, and bismuth propellants. Design details, test results (pressure developed versus current), and material compatibility issues are reported. It is concluded that EM pumps are a viable technology for application in both laboratory and flight EP conductive-propellant feed systems.

  3. A Simple Method for High-Lift Propeller Conceptual Design

    Science.gov (United States)

    German, Brian; Patterson, Michael; Borer, Nick

    2016-01-01

    In this paper, we present a simple method for designing propellers that are placed upstream of the leading edge of a wing in order to augment lift. Because the primary purpose of these "high-lift propellers" is to increase lift rather than produce thrust, these props are best viewed as a form of high-lift device; consequently, they should be designed differently than traditional propellers. We present a theory that describes how these props can be designed to provide a relatively uniform axial velocity increase, which is hypothesized to be advantageous for lift augmentation based on a literature survey. Computational modeling indicates that such propellers can generate the same average induced axial velocity while consuming less power and producing less thrust than conventional propeller designs. For an example problem based on specifications for NASA's Scalable Convergent Electric Propulsion Technology and Operations Research (SCEPTOR) flight demonstrator, a propeller designed with the new method requires approximately 15% less power and produces approximately 11% less thrust than one designed for minimum induced loss. Higher-order modeling and/or wind tunnel testing are needed to verify the predicted performance.

  4. Viscous-Inviscid Coupling Methods for Advanced Marine Propeller Applications

    Directory of Open Access Journals (Sweden)

    Martin Greve

    2012-01-01

    Full Text Available The paper reports the development of coupling strategies between an inviscid direct panel method and a viscous RANS method and their application to complex propeller ows. The work is motivated by the prohibitive computational cost associated to unsteady viscous flow simulations using geometrically resolved propellers to analyse the dynamics of ships in seaways. The present effort aims to combine the advantages of the two baseline methods in order to reduce the numerical effort without compromising the predictive accuracy. Accordingly, the viscous method is used to calculate the global flow field, while the inviscid method predicts the forces acting on the propeller. The corresponding reaction forces are employed as body forces to mimic the propeller influence on the viscous flow field. Examples included refer to simple verification cases for an isolated propeller blade, open-water validation simulations for a complete propeller, and more challenging investigations of a manoeuvring vessel in seaways. Reported results reveal a fair predictive agreement between the coupled approach and fully viscous simulations and display the efficiency of the coupled approach.

  5. Numerical study of hub taper angle on podded propeller performance

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M.F.; Veitch, B.; Bose, N. [Memorial Univ. of Newfoundland, Faculty of Engineering and Applied Science, St. John' s, Newfoundland (Canada)]. E-mail: Mohammed.Islam@nrc-cnrc.gc.ca; Liu, P. [National Research Council of Canada, Inst. for Ocean Technology (IOT), St. John' s, Newfoundland (Canada)

    2005-07-01

    Presently, the majority of podded propulsion systems are of the pulling type, because this type provides better hydrodynamic efficiency than the pushing type. There are several possible explanations for the better overall performance of a puller type podded propulsor. One is related to the difference in hub shape. Puller and pusher propellers have opposite hub taper angles, hence different hub and blade root shape. These differences cause changes in the flow condition and possibly influence the overall performance. The current study focuses on the variation in performance of pusher and puller propellers with the same blade sections, but different hub taper angles. A hyperboloidal low order source doublet steady/unsteady time domain panel method code was modified and used to evaluate effects of hub taper angle on the open water propulsive performance of some fixed pitch screw propellers used in podded propulsion systems. The modified code was first validated against measurements of two model propellers in terms of average propulsive performance and good agreement was found. Major findings include significant effects of hub taper angle on propulsive performance of tapered hub propellers and noticeable effects of hub taper angle on sectional pressure distributions of tapered hub propeller blades. (author)

  6. Investigation of Ignition of Liquid Propellant in Reservoir in Regenerative Liquid Propellant Gun Trials

    Directory of Open Access Journals (Sweden)

    D. K. Kharat

    1997-04-01

    Full Text Available It is important to understand the internal ballistic processes for the development of regenerative liquid propellant guns (RLPGs. A 30 mm RLPG test fixture was developed and firing trials were conducted to study the performance of the gun. During the trials, sometimes, combustion ignition in the reservoir took place resulting in substantial damage to the injection piston. This paper highlights the possible causes of this combustion and offers suggestions. regarding improvement in the design. An elaborate instrumentation set-up which could pinpoint the specific conditions leading to failures is suggested.

  7. Method to calculate characteristics of cavitating propeller; Cavitation wo okoshiteiru propeller no ichiseino keisanho

    Energy Technology Data Exchange (ETDEWEB)

    Maita, S.; Nakashima, A.; Ando, J.; Nakatake, K. [Kyushu University, Fukuoka (Japan)

    1998-09-04

    Based on a simple surface panel method named SQCM, we develop a method to calculate nonlinear cavity on 2-D wing by introducing the four kinds of cavity models, i.e. closed model, semi-closed model, open model and supercavitating model. This method gives pressure distribution, lift and drag of the wing. Then, by combining the QCM program, the concept of the equivalent 2-D wing and the present cavity calculation method, we obtain the characteristics of two cavitating propellers. Comparisons between calculated results and experimental ones confirm the usefulness of our method. 11 refs., 15 figs., 1 tab.

  8. Low-Cost Propellant Launch to LEO from a Tethered Balloon - 'Propulsion Depots' Not 'Propellant Depots'

    Science.gov (United States)

    Wilcox, Brian H.; Schneider, Evan G.; Vaughan, David A.; Hall, Jeffrey L.; Yu, Chi Yau

    2011-01-01

    As we have previously reported, it may be possible to launch payloads into low-Earth orbit (LEO) at a per-kilogram cost that is one to two orders of magnitude lower than current launch systems, using only a relatively small capital investment (comparable to a single large present-day launch). An attractive payload would be large quantities of high-performance chemical rocket propellant (e.g. Liquid Oxygen/Liquid Hydrogen (LO2/LH2)) that would greatly facilitate, if not enable, extensive exploration of the moon, Mars, and beyond.

  9. LNG systems for natural gas propelled ships

    Science.gov (United States)

    Chorowski, M.; Duda, P.; Polinski, J.; Skrzypacz, J.

    2015-12-01

    In order to reduce the atmospheric pollution generated by ships, the International Marine Organization has established Emission Controlled Areas. In these areas, nitrogen oxides, sulphur oxides and particulates emission is strongly controlled. From the beginning of 2015, the ECA covers waters 200 nautical miles from the coast of the US and Canada, the US Caribbean Sea area, the Baltic Sea, the North Sea and the English Channel. From the beginning of 2020, strong emission restrictions will also be in force outside the ECA. This requires newly constructed ships to be either equipped with exhaust gas cleaning devices or propelled with emission free fuels. In comparison to low sulphur Marine Diesel and Marine Gas Oil, LNG is a competitive fuel, both from a technical and economical point of view. LNG can be stored in vacuum insulated tanks fulfilling the difficult requirements of marine regulations. LNG must be vaporized and pressurized to the pressure which is compatible with the engine requirements (usually a few bar). The boil-off must be controlled to avoid the occasional gas release to the atmosphere. This paper presents an LNG system designed and commissioned for a Baltic Sea ferry. The specific technical features and exploitation parameters of the system will be presented. The impact of strict marine regulations on the system's thermo-mechanical construction and its performance will be discussed. The review of possible flow-schemes of LNG marine systems will be presented with respect to the system's cost, maintenance, and reliability.

  10. TNT equivalency of M10 propellant

    Science.gov (United States)

    Mcintyre, F. L.; Price, P.

    1978-01-01

    Peak, side-on blast overpressure and scaled, positive impulse have been measured for M10 single-perforated propellant, web size 0.018 inches, using configurations that simulate the handling of bulk material during processing and shipment. Quantities of 11.34, 22.7, 45.4, and 65.8 kg were tested in orthorhombic shipping containers and fiberboard boxes. High explosive equivalency values for each test series were obtained as a function of scaled distance by comparison to known pressure, arrival time and impulse characteristics for hemispherical TNT surface bursts. The equivalencies were found to depend significantly on scaled distance, with higher values of 150-100 percent (pressure) and 350-125 percent (positive impulse) for the extremes within the range from 1.19 to 3.57 m/cube root of kg. Equivalencies as low as 60-140 percent (pressure) and 30-75 percent (positive impulse) were obtained in the range of 7.14 to 15.8 m/cube root of kg. Within experimental error, both peak pressure and positive impulse scaled as a function of charge weight for all quantities tested in the orthorhombic configuration.

  11. WOW: light print, light propel, light point

    Science.gov (United States)

    Glückstad, Jesper; Bañas, Andrew; Aabo, Thomas; Palima, Darwin

    2012-10-01

    We are presenting so-called Wave-guided Optical Waveguides (WOWs) fabricated by two-photon polymerization and capable of being optically manipulated into any arbitrary orientation. By integrating optical waveguides into the structures we have created freestanding waveguides which can be positioned anywhere in a sample at any orientation using real-time 3D optical micromanipulation with six degrees of freedom. One of the key aspects of our demonstrated WOWs is the change in direction of in-coupled light and the marked increase in numerical aperture of the out-coupled light. Hence, each light propelled WOW can tap from a relatively broad incident beam and generate a much more tightly confined light at its tip. The presentation contains both numerical simulations related to the propagation of light through a WOW and preliminary experimental demonstrations on our BioPhotonics Workstation. In a broader context, this research shows that optically trapped micro-fabricated structures can potentially help bridge the diffraction barrier. This structure-mediated paradigm may be carried forward to open new possibilities for exploiting beams from far-field optics down to the sub-wavelength domain.

  12. Performance and slipstream characteristics of small-scale propellers at low Reynolds numbers

    Science.gov (United States)

    Deters, Robert W.

    The low Reynolds number effects of small-scale propellers were investigated. At the Reynolds numbers of interest (below 100,000), a decrease in lift and an increase in drag is common making it difficult to predict propeller performance characteristics. A propeller testing apparatus was built to test small scale propellers in static conditions and in an advancing flow. Twenty-seven off-the-shelf propellers, with diameters ranging from 2.25 in to 9 in, were tested in order to determine the general effects of low Reynolds numbers on small propellers. From these tests, increasing the Reynolds number for a propeller increases its efficiency by either increasing the thrust produced or decreasing the power. By doubling the Reynolds number of a propeller, it is not uncommon to increase the efficiency by more the 10%. Using off-the-shelf propellers limits the geometry available and finding propellers of the same geometry but of different scale is very difficult. To solve this problem, four propellers were design and built using a 3D printer. Two of the propellers were simple rectangular twisted blades of different chords. Another propeller was modeled after a full-scale propeller. The fourth propeller was created using inverse design to minimize power loss. Each propeller was built in a 5-in and 9-in diameter version in order to test a larger range of Reynolds numbers. A separate propeller blade and hub system was created to allow each propeller to be tested with different pitch angles and to test each propeller in a 2-, 3-, and 4-blade version. From the performance results of the 3D printed propellers, it was shown that propellers of different scale, but tested at the same Reynolds number, had about the same performance results. Finally, the slipstreams of different propellers were measured using a 7-hole probe. Propeller slipstreams can have a large effect on the aerodynamics of lifting surfaces downstream of the propeller. Small UAVs and MAVs flying in close proximity

  13. ANALISA PENGARUH ALIRAN FLUIDA YANG DITIMBULKAN OLEH GERAKAN PUTARAN PROPELLER PADA KAPAL IKAN TERHADAP TEKANAN PROPELLER DENGAN PENDEKATAN CFD

    Directory of Open Access Journals (Sweden)

    Samuel Samuel

    2012-04-01

    Full Text Available Dalam operasinya dilaut, suatu kapal harus memiliki kemampuan untuk mempertahankan kecepatan dinas (Vs seperti yang direncanakan. Hal ini mempunyai arti bahwa, kapal haruslah mempunyai rancangan sistem propulsi yang dapat mengatasi keseluruhan gaya-gaya hambat yang terjadi agar memenuhi standar kecepatan dinasnya. Penelitian untuk meningkatkan daya dorong propeller dari tahun ketahun terus dilakukan dengan meningkatakan efisiensi propeller. Tapi dari sisi lain usaha untuk meneliti dimana konsentrasi tegangan yang diakibatkan daya dorong propeller masih kurang dilakukan Untuk tugas akhir ini analisa yang dilakukan adalah untuk mengetahui distribusi tekanan pada propeller dan juga maximum stress yang terjadi pada propeller. Proses pembuatan model geometri dibantu dengan menggunakan software CAD dan analisanya dilakukan dengan mengunakan pendekatan CFD (Computational Fluid Dynamic sebagai sarana visualisasi.Analisa dilakukan dengan memvariasikan putaran propeller pada 100, 200, 300, 400, 500 rpm. Berdasarkan hasil perhitungan dan hasil running software CFD yang telah dilakukan didapatkan  hasil perbedaan tekanan dimana pada tiap putarannya semakin meningkat. Tekanan paling besar terjadi pada putaran 500 rpm yaiutu sebesar 28169,72 N. Dengan menggunakan software MSC NASTRAN didapatkan nilai maksimum strees sebesar 13,1 N/mm2 akan tetapi material ini masih dalam batas aman karena hasil perhitungan safety factor material bahan  didapat nilai 33,87.

  14. Beta-carotene

    Science.gov (United States)

    ... and deterioration of the lining of the mouth (oral mucositis). Taking beta-carotene by mouth doesn’t appear to prevent the development of oral mucositis during radiation therapy or chemotherapy. Pancreatic cancer. Taking ...

  15. Neutrinoless double beta decay

    International Nuclear Information System (INIS)

    The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given. (author)

  16. Neutrinoless double beta decay

    Indian Academy of Sciences (India)

    Kai Zuber

    2012-10-01

    The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given.

  17. [High beta tokamak research

    International Nuclear Information System (INIS)

    Our activities on High Beta Tokamak Research during the past 20 months of the present grant period can be divided into six areas: reconstruction and modeling of high beta equilibria in HBT; measurement and analysis of MHD instabilities observed in HBT; measurements of impurity transport; diagnostic development on HBT; numerical parameterization of the second stability regime; and conceptual design and assembly of HBT-EP. Each of these is described in some detail in the sections of this progress report

  18. High beta multipoles

    International Nuclear Information System (INIS)

    Multipoles are being employed as devices to study fusion issues and plasma phenomena at high values of beta (plasma pressure/magnetic pressure) in a controlled manner. Due to their large volume, low magnetic field (low synchrotron radiation) region, they are also under consideration as potential steady state advanced fuel (low neutron yield) reactors. Present experiments are investigating neoclassical (bootstrap and Pfirsch-Schlueter) currents and plasma stability at extremely high beta

  19. Autoregressive conditional beta

    OpenAIRE

    Yunmi Kim

    2012-01-01

    The capital asset pricing model provides various predictions about equilibrium expected returns on risky assets. One key prediction is that the risk premium on a risky asset is proportional to the nondiversifiable market risk measured by the asset's beta coefficient. This paper proposes a new method for estimating and drawing inferences from a time-varying capital asset pricing model. The proposed method, which can be considered a vector autoregressive model for multiple beta coefficients, is...

  20. Compact and Integrated Liquid Bismuth Propellant Feed System

    Science.gov (United States)

    Polzin, Kurt A.; Stanojev, Boris; Korman, Valentin; Gross, Jeffrey T.

    2007-01-01

    Operation of Hall thrusters with bismuth propellant has been shown to be a promising path toward high-power, high-performance, long-lifetime electric propulsion for spaceflight missions [1]. There has been considerable effort in the past three years aimed at resuscitating this promising technology and validating earlier experimental results indicating the advantages of a bismuth-fed Hall thruster. A critical element of the present effort is the precise metering of propellant to the thruster, since performance cannot be accurately assessed without an accurate accounting of mass flow rate. Earlier work used a pre./post-test propellant weighing scheme that did not provide any real-time measurement of mass flow rate while the thruster was firing, and makes subsequent performance calculations difficult. The motivation of the present work is to develop a precision liquid bismuth Propellant Management System (PMS) that provides hot, molten bismuth to the thruster while simultaneously monitoring in real-time the propellant mass flow rate. The system is a derivative of our previous propellant feed system [2], but the present system represents a more compact design. In addition, all control electronics are integrated into a single unit and designed to reside on a thrust stand and operate in the relevant vacuum environment where the thruster is operating, significantly increasing the present technology readiness level of liquid metal propellant feed systems. The design of various critical components in a bismuth PMS are described. These include the bismuth reservoir and pressurization system, 'hotspot' flow sensor, power system and integrated control system. Particular emphasis is given to selection of the electronics employed in this system and the methods that were used to isolate the power and control systems from the high-temperature portions of the feed system and thruster. Open loop calibration test results from the 'hotspot' flow sensor are reported, and results of

  1. Propelling Exploration to the Moon and Beyond

    Science.gov (United States)

    Cook, Stephen A.

    2009-01-01

    As the Constellation Program enters its fourth year, the Ares Projects have made substantial progress toward sending human explorers beyond Earth orbit. The Ares I crew launch vehicle, which will take six astronauts or cargo to the International Space Station or four astronauts to rendezvous with Ares V for missions to the Moon, is the first human-rated vehicle NASA has developed in over 30 years. Since the Exploration Systems Architecture Study in 2005, the Ares Projects have completed a successful system requirements review, system definition review, and preliminary design review for the Ares I crew launch vehicle. The Ares I elements are well into development, beginning with the Shuttle-derived, five-segment solid rocket motor that will provide first-stage propulsion. The first stage team has poured its first production simulation article motor and will be pouring and firing the first five-segment development motor in 2009. Large-scale tooling has been installed and tested to produce propellant tanks for the liquid-fuel upper stage at Marshall Space Flight Center (MSFC) in Alabama. The initial upper stage units and main propulsion test article will be manufactured and tested at MSFC before transferring to Michoud Assembly Facility in Louisiana. The upper stage engine team has completed powerpack testing using Apollo J-2 heritage hardware and begun construction of a new altitude test stand at Stennis Space Center in Mississippi. The flight and integrated testing group has designed and built hardware for the Ares I-X test flight scheduled for 2009, as well as begun refurbishing existing infrastructure to support ground testing. Additionally, a base configuration has been selected for the Ares V cargo launch vehicle, which will send the Altair lunar lander and Orion to the Moon. Today, the Ares Projects are well on the way to building America s next generation of exploration-capable launch vehicles.

  2. Producing propellants from water in lunar soil using solar lasers

    Science.gov (United States)

    de Morais Mendonca Teles, Antonio

    The exploration of the Solar System is directly related to the efficiency of engines designed to explore it, and consequently, to the propulsion techniques, materials and propellants for those engines. With the present day propulsion techniques it is necessary great quantities of propellants to impulse a manned spacecraft to Mars and beyond in the Solar System, which makes these operations financially very expensive because of the costs involved in launching it from planet Earth, due to its high gravity field strength. To solve this problem, it is needed a planetary place with smaller gravity field strength, near to the Earth and with great quantities of substances at the surface necessary for the in-situ production of propellants for spacecrafts. The only place available is Earth's natural satellite the Moon. So, here in this paper, I propose the creation of a Lunar Propellant Manufacturer. It is a robot-spacecraft which can be launched from Earth using an Energia Rocket, and to land on the Moon in an area (principally near to the north pole where it was discovered water molecules ice recently) with great quantities of oxygen and hydrogen (propellants) in the silicate soil, previously observed and mapped by spacecrafts in lunar orbit, for the extraction of those molecules from the soil and the in-situ production of the necessary propellants. The Lunar Propellant Manufacturer (LPM) spacecraft consists of: 1) a landing system with four legs (extendable) and rovers -when the spacecraft touches down, the legs retract in order that two apparatuses, analogue to tractor's wheeled belts parallel sided and below the spacecraft, can touch firmly the ground -it will be necessary for the displacement of the spacecraft to new areas with richer propellants content, when the early place has already exhausted in propellants; 2) a digging machine -a long, resistant extendable arm with an excavator hand, in the outer part of the spacecraft -it will extend itself to the ground

  3. Discussion on Mechanism of Breech-Blow Caused by Propellant Charge

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    From the view point of launch safety caused by fracture of propellant charge, this paper points out that the safety criterion of pressure wave is inadequate to evaluate the launch safety of propellant charge based on the initial negative differential pressure and sensitivity tests. Generally, the maximum barrel pressure does not depend upon the intensity of pressure wave correspondingly. The pressure wave intensity can not describe the fracture degree of propellant charge in chamber and reflect the mechanical environment of propellant charge fracturing exactly and wholly. The evaluation criterion for launch safety of propellant charge should be built on the basis of depicting the fracture degree of propellant bed.

  4. Flyer impact experiment to study vulnerability and reactivity of gun propellant formulations

    International Nuclear Information System (INIS)

    A flyer impact experiment to study the vulnerability of propellant formulations is designed. The shock wave conditions of the impacting flyer are related to the energy transfer from a single detonating propellant grain as found by numerical simulation. A propellant will react due to the imposed shock from the impacting flyer. The reactivity of the propellant formulation is quantified by the volume of the dent created in an aluminium witness block. This flyer impact experiment simulates the propellant grain-to-grain sympathetic reaction in a shaped charge attack on a gun propellant bed

  5. Electromagnetic Pumps for Conductive-Propellant Feed Systems

    Science.gov (United States)

    Markusic, Thomas E.; Polzin, Kurt A.; Dehoyos, Amado

    2005-01-01

    Prototype electromagnetic pumps for use with lithium and bismuth propellants were constructed and tested. Such pumps may be used to pressurize future electric propulsion liquid metal feed systems, with the primary advantages being the compactness and simplicity versus alternative pressurization technologies. Design details for two different pumps are described: the first was designed to withstand (highly corrosive) lithium propellant, and t he second was designed to tolerate the high temperature required to pump liquid bismuth. Both qualitative and quantitative test results are presented. Open-loop tests demonstrated the capability of each device to electromagnetically pump its design propellant (lithium or bismuth). A second set of tests accurately quantified the pump pressure developed as a function of current. These experiments, which utilized a more easily handled material (gallium), demonstrated continuously-adjustable pump pressure levels ranging from 0-100 Torr for corresponding input current levels of 0-75 A. While the analysis and testing in this study specifically targeted lithium and bismuth propellants, the underlying design principles should be useful in implementing liquid metal pumps in any conductive-propellant feed system.

  6. Evaluation of Energetic Plasticisers for Solid Gun Propellant

    Directory of Open Access Journals (Sweden)

    R.S. Damse

    2008-01-01

    Full Text Available This paper reports the evaluation of four different energetic plasticisers, viz., glycidyl azidepolymer (GAP, MW = 390, 1,5-diazido-3-nitrazapentane (DANPE, ethylene-glycol-bis-azido-acetate (EGBAA and N-n-butyl-N-(2 nitroxyethyl nitramine (n-Bu-NENA separately into highenergy gun propellant containing 28 per cent NC (13.1 N %, 65 per cent RDX, 6 per cent di-octyl-phthahate (DOP and 1 per cent carbamite.  Four different propellant compositions based on theenergetic plasticiser have been formulated separately with the replacement of non-energeticplasticiser, DOP. The propellants were processed by standard solvent method and evaluatedexperimentally along with the control composition to determine the ballistic parameters, cal-val,sensitivity, thermal characterisation, thermal stability and mechanical properties. The performanceof the propellants containing the energetic plasticiser has  been compared with that of thecontrol composition containing the non-energetic plasticiser, DOP so as to assess the suitabilityof the energetic plasticiser for the futuristic gun propellant formulations. It has been found outthat n-Bu-NENA is the superior plasticiser among the four energetic plasticisers evaluated inthis study.Defence Science Journal, 2008, 58(1, pp.86-93, DOI:http://dx.doi.org/10.14429/dsj.58.1627

  7. Propellant acquisition for single-stage rocket technology

    Science.gov (United States)

    Grayson, G.; Distefano, E.

    1993-06-01

    An analytical design approach defines the liquid oxygen (LO2) propellant-acquisition system for the vertical-take-off and vertical-landing DC-X flight test vehicle. The DC-X trajectory includes a rotation maneuver in which the vehicle pitches from a nose-first to a tail-first orientation. The 8-ft diameter LO2 tank accommodates outflow rates as high as 120 lbm/sec, while vehicle drag forces result in a lateral acceleration approaching 25 ft/sq sec during rotation. FLOW-3D computational results show that, without propellant control, these conditions cause the LO2 to slosh within the tank and expose the outlet to ullage gas during the rotation maneuver. Using FLOW 3-D simulations of several baffle configurations, one propellant acquisition concept is selected. In this concept, a simple cone-shaped containment baffle compartmentalizes the tank and an outlet extension offsets the outlet to where the propellant is biased. The final design incorporates a factor of safety greater than 2 resulting in continuous coverage of the outlet by propellant as validated by FLOW-3D simulation.

  8. Cryogenic thermal system analysis for orbital propellant depot

    Science.gov (United States)

    Chai, Patrick R.; Wilhite, Alan W.

    2014-09-01

    In any manned mission architecture, upwards of seventy percent of all payload delivered to orbit is propellant, and propellant mass fraction dominates almost all transportation segments of any mission requiring a heavy lift launch system like the Saturn V. To mitigate this, the use of an orbital propellant depot has been extensively studied. In this paper, a thermal model of an orbital propellant depot is used to examine the effects of passive and active thermal management strategies. Results show that an all passive thermal management strategy results in significant boil-off for both hydrogen and oxygen. At current launch vehicle prices, these boil-offs equate to millions of dollars lost per month. Zero boil-off of propellant is achievable with the use of active cryocoolers; however, the cooling power required to produce zero-boil-off is an order of magnitude higher than current state-of-the-art cryocoolers. This study shows a zero-boil-off cryocooler minimum power requirement of 80-100 W at 80 K for liquid oxygen, and 100-120 W at 20 K for liquid hydrogen for a representative Near-Earth Object mission. Research and development effort is required to improve the state-of-the-arts in-space cryogenic thermal management.

  9. Recent Advances and Applications in Cryogenic Propellant Densification Technology

    Science.gov (United States)

    Tomsik, Thomas M.

    2000-01-01

    This purpose of this paper is to review several historical cryogenic test programs that were conducted at the NASA Glenn Research Center (GRC), Cleveland, Ohio over the past fifty years. More recently these technology programs were intended to study new and improved denser forms of liquid hydrogen (LH2) and liquid oxygen (LO2) cryogenic rocket fuels. Of particular interest are subcooled cryogenic propellants. This is due to the fact that they have a significantly higher density (eg. triple-point hydrogen, slush etc.), a lower vapor pressure and improved cooling capacity over the normal boiling point cryogen. This paper, which is intended to be a historical technology overview, will trace the past and recent development and testing of small and large-scale propellant densification production systems. Densifier units in the current GRC fuels program, were designed and are capable of processing subcooled LH2 and L02 propellant at the X33 Reusable Launch Vehicle (RLV) scale. One final objective of this technical briefing is to discuss some of the potential benefits and application which propellant densification technology may offer the industrial cryogenics production and end-user community. Density enhancements to cryogenic propellants (LH2, LO2, CH4) in rocket propulsion and aerospace application have provided the opportunity to either increase performance of existing launch vehicles or to reduce the overall size, mass and cost of a new vehicle system.

  10. Design and Analysis of Composite Propeller Blade for Aircraft

    Directory of Open Access Journals (Sweden)

    Madhusudhan BM

    2014-09-01

    Full Text Available Fiber reinforced composites is used for twin blade propeller because of its high strength, low temperature applications. Fiber has to be oriented in the loading direction while designing the composite propeller blade. The blade geometry and design are more complex involving many controlling parameters. In the present work a methodology to design a composite propeller to analyze its strength and deformation using ANSYS software. The weight of the composite blade is reduced compared to wooden blade by adopting the shell model. The present work is to carryout the static analysis of composite propeller which is a combination CFRP (Carbon Fiber Reinforced Plastics and epoxy resin materials. In order to evaluate the effectiveness of the composite blade over wooden stress analysis is performed on both the blades. To define the orientation and number of layers in the composite blade ANSYS classic software is used. From the results, the stresses of composite propeller obtained in static analysis are within the allowable stress limit. The deflection of the composite blade is less compared to the wooden blade.

  11. Simulation of the Propeller Disk Inside the Symmetrical Channel

    Directory of Open Access Journals (Sweden)

    Kyncl Martin

    2014-03-01

    Full Text Available We work with the system of equations describing non-stationary compressible turbulent fluid flow, and we focus on the numerical solution of these equations, and on the boundary conditions. The computational simulation of the propeller disk is a demanding and time-consuming task. Here the propeller disk is represented by the distribution of the vector of velocities along its radius. The main purpose is to describe the special compatible conditions used to simulate the propeller disk on the both its sides. In order to construct these conditions we analyze the equations in the close vicinity of the boundary. We use the analysis of the exact solution of the Riemann problem in order to solve this local boundary problem. The one-side modification of this problem has to be complemented with some other conditions. At the back side of the propeller disk, it is advantageous to use total density and the total pressure distribution, coming from the known distribution of axial velocities on the disk and the total state values at the inlet, and extra added velocities of rotation. At the front side of the disk, it is preferable to use the distribution of the flowing mass, known from the state values computed on the back side of the disk. We analyze the solution of these particular problems. We show the computational results of the flow around such propeller disk, obtained with the own-developed code for the solution of the 3D axis-symmetrical compressible turbulent gas flow.

  12. Propeller thoracodorsal artery perforator flap for breast reconstruction

    Science.gov (United States)

    Angrigiani, Claudio; Escudero, Ezequiel; Artero, Guillermo; Gercovich, Gustavo; Deza, Ernesto Gil

    2014-01-01

    Background The thoracodorsal artery perforator (TDAP) flap has been described for breast reconstruction. This flap requires intramuscular dissection of the pedicle. A modification of the conventional TDAP surgical technique for breast reconstruction is described, utilizing instead a propeller TDAP flap. The authors present their clinical experience with the propeller TDAP flap in breast reconstruction alone or in combination with expanders or permanent implants. Methods From January 2009 to February 2013, sixteen patients had breast reconstruction utilizing a propeller TDAP flap. Retrospective analysis of patient characteristics, clinical indications, procedure and outcomes were performed. The follow-up period ranged from 4 to 48 months. Results Sixteen patients had breast reconstruction using a TDAP flap with or without simultaneous insertion of an expander or implant. All flaps survived, while two cases required minimal resection due to distal flap necrosis, healing by second intention. There were not donor-site seromas, while minimal wound dehiscence was detected in two cases. Conclusions The propeller TDAP flap appears to be safe and effective for breast reconstruction, resulting in minimal donor site morbidity. The use of this propeller flap emerges as a true alternative to the traditional TDAP flap. PMID:25207210

  13. Propellant-Flow-Actuated Rocket Engine Igniter

    Science.gov (United States)

    Wollen, Mark

    2013-01-01

    A rocket engine igniter has been created that uses a pneumatically driven hammer that, by specialized geometry, is induced into an oscillatory state that can be used to either repeatedly impact a piezoelectric crystal with sufficient force to generate a spark capable of initiating combustion, or can be used with any other system capable of generating a spark from direct oscillatory motion. This innovation uses the energy of flowing gaseous propellant, which by means of pressure differentials and kinetic motion, causes a hammer object to oscillate. The concept works by mass flows being induced through orifices on both sides of a cylindrical tube with one or more vent paths. As the mass flow enters the chamber, the pressure differential is caused because the hammer object is supplied with flow on one side and the other side is opened with access to the vent path. The object then crosses the vent opening and begins to slow because the pressure differential across the ball reverses due to the geometry in the tube. Eventually, the object stops because of the increasing pressure differential on the object until all of the kinetic energy has been transferred to the gas via compression. This is the point where the object reverses direction because of the pressure differential. This behavior excites a piezoelectric crystal via direct impact from the hammer object. The hammer strikes a piezoelectric crystal, then reverses direction, and the resultant high voltage created from the crystal is transferred via an electrode to a spark gap in the ignition zone, thereby providing a spark to ignite the engine. Magnets, or other retention methods, might be employed to favorably position the hammer object prior to start, but are not necessary to maintain the oscillatory behavior. Various manifestations of the igniter have been developed and tested to improve device efficiency, and some improved designs are capable of operation at gas flow rates of a fraction of a gram per second (0

  14. URANS COMPUTATION OF CAVITATING FLOWS AROUND SKEWED PROPELLERS

    Institute of Scientific and Technical Information of China (English)

    LIU Yan; ZHAO Peng-fei; WANG Qiang; CHEN Zhao-hui

    2012-01-01

    Cavitating flows around skewed propellers are investigated numerically by means of the unsteady Reynolds Averaged Navier-Stokes (RANS) Equation method.The standard k-ε turbulence and the modified Z-G-B cavitation models are employed.A measured nominal wake is used for the inlet velocity boundary condition.Predicted cavitating evolution processes and tip cavity patterns are compared with experimental observations.In addition,the influence of the skew angles on the cavitation and unsteadiness performances of propellers operating in a non-uniform wake is also studied Results show that the modified Z-G-B cavitation model performs better to simulate the cavitating flow cases studied in this paper.Comparisons demonstrate that the skewed propeller with a skew angle of 20° is the best choice for a given stern wake with a assigned thrust and the minimum force fluctuations.

  15. The Effect of Slipstream Obstructions on Air Propellers

    Science.gov (United States)

    Lesley, E P; Woods, B M

    1924-01-01

    The screw propeller on airplanes is usually placed near other objects, and hence its performance may be modified by them. Results of tests on propellers free from slip stream obstructions, both fore and aft, are therefore subject to correction, for the effect of such obstructions and the purpose of the investigation was to determine the effect upon the thrust and torque coefficients and efficiency, for previously tested air propellers, of obstructions placed in the slip stream, it being realized that such previous tests had been conducted under somewhat ideal conditions that are impracticable of realization in flight. Simple geometrical forms were used for the initial investigation. Such forms offered the advantage of easy, exact reproduction at another time or in other laboratories, and it was believed that the effects of obstructions usually encountered might be deduced or surmise from those chosen.

  16. Effect of Propeller Slipstream on Wing and Tail

    Science.gov (United States)

    Stuper, J

    1938-01-01

    The results of wind tunnel tests for the determination of the effect of a jet on the lift and downwash of a wing are presented in this report. In the first part, a jet without rotation and with constant velocity distribution is considered - the jet being produced by a specially designed fan. Three-component, pressure distribution, and downwash measurements were made and the results compared with existing theory. The effect of a propeller slipstream was investigated in the second part. In the two cases the jet axis coincided with the undisturbed wind direction. In the third part the effect of the inclination of the propeller axis to the wing chord was considered, the results being obtained for a model wing with running propeller.

  17. Studies of solid propellant combustion with pulsed radiography

    Science.gov (United States)

    Godai, T.; Tanemura, T.; Fujiwara, T.; Shimizu, M.

    1987-01-01

    Pulsed radiography was applied to observe solid propellant surface regression during rocket motor operation. Using a 150 KV flash X-ray system manufactured by the Field Emission Corporation and two kinds of film suppliers, images of the propellant surface of a 5 cm diameter end burning rocket motor were recorded on film. The repetition frame rate of 8 pulses per second and the pulse train length of 10 pulses are limited by the capability of the power supply and the heat build up within the X-ray tube, respectively. The experiment demonstrated the effectiveness of pulsed radiography for observing solid propellant surface regression. Measuring the position of burning surface images on film with a microdensitometer, quasi-instantaneous burning rate as a function of pressure and the variation of characteristic velocity with pressure and gas stay time were obtained. Other research items to which pulsed radiography can be applied are also suggested.

  18. Role of Bimodal RDX in LOVA Gun Propellant Combustion

    Directory of Open Access Journals (Sweden)

    M. M. Joshi

    1998-07-01

    Full Text Available Present investigation reports the results of systematic studies on the use of bimodal RDX in low-vulnerability ammunition (LOVA gun propellants. Several formulations based on bimodal RDX as oxidiser, cellulose acetate as binder, and diocty1 phthalate or triacetin as plasticizer were processed with different proportions of 5 micrometer and 20 micrometer particle size of RDX samples in the range 100:0 to 60:40 ratios. The effect of varying the proportion of fine RDX of the two particle sizes on propellant burning behaviour was found to be quite significant. The study concluded that by using bimodal RDX, it is possible to modify burning behaviour without sacrificing low-vulnerability aspects of LOVA propellants.

  19. On Performance Evaluation of a New Liquid Propellant

    Directory of Open Access Journals (Sweden)

    S. P. Panda

    1986-01-01

    Full Text Available A blend of 3-carene and cardanol in 70:30 weight proportion exhibits synergistic hypergolic ignition with red fuming nitric acid (RFNA as oxidizer. Attempts have been made to evaluate this new propellant by theoretical calculationof performance parameters and verification of the results by static firing of a 10 kg thrust rocket motor around 20 atmosphers of chamber pressure. At an oxidizer-to-fuel weight ratio (O/F of 3.34 (RFNA used had 21% N204 and 5% by weight of concentrated sulphuric acid as catalyst, the propellant produced a reasonably smooth pressure-time curve with an ignition delay of 35 milliseconds. The theoretical characteristic velocity value matched well with the experimental. No carbon residue was left in the rocket motor after firing. Specific impulse (theoretical of the propellant has been found to be 223.8 seconds at chamber pressure, 20 atmos and exist pressure, 1 atmos.

  20. Feedback control of an ensemble of self-propelled particles

    Science.gov (United States)

    Wu, Jian-chun; Chen, Qun; Wang, Rang; Ai, Bao-quan

    2015-06-01

    Rectified transport of self-propelled particles in an asymmetric period potential is numerically investigated by employing a feedback control protocol. The feedback control is switched on and off depending on the direction of the self-propelled speed. It is found that the direction of the transport is determined by the asymmetry of the potential and the feedback control strength. In the presence of feedback control, the directed transport can be improved significantly by increasing the feedback control strength under appropriate conditions. For large ensembles of particles, however, the feedback control will not obviously affect the transport of self-propelled particles. The present studies may be relevant to some applications in biology and nanotechnology, and provide the predicting results in experiments of active particles.

  1. Use of A Shatter Test Vessel to Assess Propellant Safety

    Institute of Scientific and Technical Information of China (English)

    Clive WOODLEY; Peter HENNING

    2015-01-01

    At low temperatures,gun propellant grains may become brittle and this can lead to fracture or shatter of the grains during gun firing.Should this event occur then it will result in an increase in the burning surface of the propellant and will give rise to a change in ballistic performance.Also,if the resultant over pressure is sufficient,a breech failure may result.Understanding the propensity of a grain to fracture or shatter is therefore important in determining its safety in use.This document describes a test that may be used to derive knowledge and to quantify the physical behaviour of a gun propellant grain at the low temperatures at which fracture or shatter is most likely to occur.

  2. Design and performance verification of a passive propellant management system

    Science.gov (United States)

    Hess, D. A.; Regnier, W. W.

    1978-01-01

    This paper describes the design and verification testing of a reusable passive propellant management system. The system was designed to acquire propellant in low- or zero-g environments and also retain this propellant under high axially directed accelerations that may be experienced during launch and orbit-to-orbit transfer. The system design requirements were established to satisfy generally the requirements for a large number of potential NASA and military applications, such as orbit-to-orbit shuttles and satellite vehicles. The resulting concept was a multicompartmented tank with independent surface tension acquisition channels in each compartment. The tank was designed to provide a minimum expulsion efficiency of 98 percent when subjected to the simultaneous conditions of acceleration, vibration, and outflow. The system design has the unique capability to demonstrate low-g performance in a 1-g test environment, and the test program summarized was structured around this capability.

  3. Composite propellant tank study for very low cost space transportation

    Science.gov (United States)

    Moser, D. J.; Keith, E. L.

    1992-01-01

    A study of life-cycle cost is conducted to determine acceptable options for composite propellant tanks at low cost and weight and for use at moderate pressures. The review examines all cost issues relevant to the production, mass, applications, and reliability of the tanks for pressure-fed rockets. Specific attention is given to the manufacturing and life-cycle issues relevant to the use of composite materials in this application since composites are effective materials for liquid propellant tanks. Specific costs and parametric considerations are given for several tank candidates with 62,303-lb capacities. The mass sensitivity of the fourth stage for the concept vehicle is shown to be high, and the use of a 325-psi fourth-stage tank is shown to yield the minimum cost/lb for the stage. Wound S-glass/epoxy composites can be employed as cost-effective replacements for steel in the design of liquid-propellant tanks.

  4. Wind tunnel tests of stratospheric airship counter rotating propellers

    Directory of Open Access Journals (Sweden)

    Yaxi Chen

    2015-01-01

    Full Text Available Aerodynamic performance of the high-altitude propeller, especially the counter rotation effects, is experimentally studied. Influences of different configurations on a stratospheric airship, included 2-blade counter-rotating propeller (CRP, dual 2-blade single rotation propellers (SRPs and 4-blade SRP, are also indicated. This research indicates that the effect of counter rotation can greatly improve the efficiency. It shows that the CRP configuration results in a higher efficiency than the dual 2-blade SRPs configuration or 4-blade SRP configuration under the same advance ratio, and the CRP configuration also gains the highest efficiency whether under the situation of providing the same trust or absorbing the same power. It concludes that, for a stratospheric airship, the CRP configuration is better than the multiple SRPs configuration or a multi-blade SRP one.

  5. The Effect of the Propeller Jet on Pile Groups

    Institute of Scientific and Technical Information of China (English)

    Kubilay Cihan

    2014-01-01

    The objective of this study is to determine the effect of jet propeller on the damage of berthing structures combined of armoured slope with pile groups. For this purpose, scour measurements were performed for four types berthing structures, which were armoured slope with tandem arrangements of piles for two and three piles and with side by side arrangements of piles for two and three piles. The effect of gap between piles on damage was investigated. The damage level induced by propeller jet between piles was determined. The gaps were 1, 2, 3, and 4 times the pile diameter. Three different values of Rpm (690, 820, and 950) were chosen for the tests. The diameter of circular piles is 40 mm. The slope ratio was 1/3 and the diameter of propeller was 10 cm.

  6. The Application of Erosive Burning to Propellant Charge Interior Ballistics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-lin

    2009-01-01

    Erosive burning is a common burning phenomenon of the gunpowder with inner holes. The actual combustion law of the gunpowder with inner holes can be changed by erosive burning. Pressure difference between the inner and the outer of hole caused by loading density variation of the propellant charge makes erosive burning occur at inner holes during in-bore burning. The effect of erosive burning on burning speed of the propellant is studied by using the effects of flow rate, heat transfer and erosion of the combustion gas in inner holes on burning rate. The mathematic model of erosive burning of the propellant is established. The effects of the factors such as loading density, inner hole size and grain length on erosive burning and interior ballistic performance are analyzed .The method to improve the bore pressure for small charge mass and small firing range by erosive burning is proposed.

  7. Flow measurement around a model ship with propeller and rudder

    Energy Technology Data Exchange (ETDEWEB)

    Van, S.H.; Yoon, H.S.; Lee, Y.Y.; Park, I.R. [Korea Research Institute of Ships and Ocean Engineering, KORDI, Marine Transportation Systems Laboratory, Daejeon (Korea); Kim, W.J. [Mokpo National University, Department of Naval Architecture and Marine Engineering, Jeonnam (Korea)

    2006-04-15

    For the design of hull forms with better resistance and propulsive performance, it is essential to understand flow characteristics, such as wave and wake development, around a ship. Experimental data detailing the local flow characteristics are invaluable for the validation of the physical and numerical modeling of computational fluid dynamics (CFD) codes, which are recently gaining attention as efficient tools for hull form evaluation. This paper describes velocity and wave profiles measured in the towing tank for the KRISO 138,000 m{sup 3} LNG carrier model with propeller and rudder. The effects of propeller and rudder on the wake and wave profiles in the stern region are clearly identified. The results contained in this paper can provide an opportunity to explore integrated flow phenomena around a model ship in the self-propelled condition, and can be added to the International Towing Tank Conference benchmark data for CFD validation as the previous KCS and KVLCC cases. (orig.)

  8. Multi-shot PROPELLER for high-field preclinical MRI

    Science.gov (United States)

    Pandit, Prachi; Qi, Yi; Story, Jennifer; King, Kevin F.; Johnson, G. Allan

    2012-01-01

    With the development of numerous mouse models of cancer, there is a tremendous need for an appropriate imaging technique to study the disease evolution. High-field T2-weighted imaging using PROPELLER MRI meets this need. The 2-shot PROPELLER technique presented here, provides (a) high spatial resolution, (b) high contrast resolution, and (c) rapid and non-invasive imaging, which enables high-throughput, longitudinal studies in free-breathing mice. Unique data collection and reconstruction makes this method robust against motion artifacts. The 2-shot modification introduced here, retains more high-frequency information and provides higher SNR than conventional single-shot PROPELLER, making this sequence feasible at high-fields, where signal loss is rapid. Results are shown in a liver metastases model to demonstrate the utility of this technique in one of the more challenging regions of the mouse, which is the abdomen. PMID:20572138

  9. Procedure for noise prediction and optimization of advanced technology propellers

    Science.gov (United States)

    Jou, W. H.; Bernstein, S.

    1979-01-01

    The sound field due to a propeller operating at supersonic tip speed in a uniform flow was investigated. Using the fact that the wave front in a uniform stream is a convected sphere, the fundamental solution to the convected wave equation was easily obtained. The Fourier coefficients of the pressure signature were obtained by a far field approximation, and are expressed as an integral over the blade platform. It is shown that cones of silence exist fore and aft the propeller plane. The semiapex angles are shown. These angles are independent of the individual Mach components such as the flight Mach number and the rotation Mach number. The result is confirmed by the computation of the ray path of the emitted Mach waves. The Doppler amplification factor strengthens the signal behind the propeller while it weakens that upstream.

  10. Applicability Study of Composite Laminates to the Cryogenic Propellant Tanks

    Science.gov (United States)

    Aoki, T.; Ishikawa, T.

    2002-01-01

    Extensive application of light weight composite materials is one of the major technical challenges for drastic reduction of structural weight of the planned reusable launch vehicles (RLV) and space planes. Cryogenic propellant tanks are the dominating structural components of the vehicle structure and thus the application of carbon fiber reinforced plastics (CFRP) to these components is one of the most promising but challenging technologies for achieving the aimed goal of weight reduction. Research effort has been made to scrutinize the cryogenic mechanical performance of currently available candidates of CFRP material systems suitable for use under cryogenic conditions. Seven different types of material systems of CFRP are chosen and are experimentally and analytically evaluated to discuss their applicability to the liquid propellant tanks and to provide basic information for material selections. Static tensile tests were conducted with quasi-isotropic laminates to acquire static strengths, both under cryogenic and room temperatures. The development of matrix cracks and free-edge delaminations were also experimentally investigated and were compared with the numerical calculations. Interlaminar fracture toughness at cryogenic temperature was also evaluated to investigate the damage susceptibility of the materials. The decrease in matrix crack onset stresses observed in the laminate performance experiments suggested that the propellant leakage may be a key issue when applying CFRP to the propellant tanks, as well as the durability concern. Thus the propellant leakage under matrix crack accumulation was simulated by the gas helium leakage tests. Leakage model was also developed and successfully applied to the prediction of the propellant leakage. Preliminary results of adhesive joint tests under cryogenic conditions will also be referred to.

  11. Initial steps toward automation of a propellant processor

    Science.gov (United States)

    Schallhorn, Paul; Ramohalli, Kumar

    1990-01-01

    This paper presents the results from an experimental study aimed at ultimately automating the mixing of propellants in order to minimize unintended variations usually attributed to human error. The water heater and delivery system of a one-pint Baker-Perkins (APV) vertical mixer are automated with computer control. Various innovations are employed to introduce economy and low thermal inertia. Some of these include twin heaters/reservoirs instead of one large reservoir, a compact water mixer for achieving the desired temperature quickly, and thorough insulation of the entire water system. The completed system is tested during two propellant mixes. The temperature uniformly is proven through careful measurements employing several local thermocouples.

  12. Flocking States of Self-Propelling Particles in Free Space

    Science.gov (United States)

    Leung, Kwan-Tai; Chen, Hsuan-Yi

    We present particle-based simulations for the flocking behavior of self-propelling particles. Built upon previous models, our models include realistic but simple rules for the self-propelling, drag, and inter-particle interactions. Depending on both the strength and range of the interactions, a host of stationary phases appear, including independent wandering, formation flight, swarm, and rotating vortex. Of particular interest, we determine that the rotating flock can only arise in the absence of long-range alignment. We also construct a phenomenological continuum model and obtain steady-state solutions for the rotating state.

  13. Diagnosis of the jet-propelled engine by vibration analysis

    Directory of Open Access Journals (Sweden)

    Mariusz ŻOKOWSKI

    2009-01-01

    Full Text Available In this paper presented works connected with the preparation of the active experiment with the jet-propelled engine. The experiment was prepared and done at the Air Force Institute of Technology. The main aim of this preparation was the explanation of the causes of the damages of military aerial ships after air incidents, notified damages in the process of exploitation and obtainment of the vibration answer on simulated damages.The exit test of the jet-propelled engine was the point of the reference after the repair in the Military Aviation Depot.

  14. Diagnosis of the jet-propelled engine by vibration analysis

    OpenAIRE

    Mariusz ŻOKOWSKI; Marek SZCZEKALA; Spychała, Jarosław

    2009-01-01

    In this paper presented works connected with the preparation of the active experiment with the jet-propelled engine. The experiment was prepared and done at the Air Force Institute of Technology. The main aim of this preparation was the explanation of the causes of the damages of military aerial ships after air incidents, notified damages in the process of exploitation and obtainment of the vibration answer on simulated damages.The exit test of the jet-propelled engine was the point of the re...

  15. Strain Gage Measurement System to Determine Cryogenic Propellant Tank Level

    Science.gov (United States)

    Figueroa, Fernando; St.Cyr, William W.; VanDyke, David; McVay, Greg; Mitchell, Mark; Langford, Lester

    2003-01-01

    Measurement of tank level, particularly for cryogenic propellants, has proven to be a difficult proposition. Current methods based on differential pressure, capacitance sensors, temperature sensors, etc.; do not provide sufficiently accurate or robust measurements, especially at run time. This paper describes a simple, but effective method to determine propellant volume by measuring very small deformations of the structure supporting the tank. Results of a laboratory study to validate the method, and experimental data from a deployed system are presented. A comparison with an existing differential pressure sensor shows that the strain gage system provides a very good quality signal even during pressurization.

  16. Dynamic Model for Thrust Generation of Marine Propellers

    DEFF Research Database (Denmark)

    Blanke, Mogens; Lindegaard, Karl-Petter; Fossen, Thor I.

    2000-01-01

    Mathematical models of propeller thrust and torque are traditionally based on steady state thrust and torque characteristics obtained in model basin or cavitation tunnel tests. Experimental results showed that these quasi steady state models do not accurately describe the transient phenomena in a...... thruster. A recently published dynamic model was based on the experimental observations. Describing zero advance speed conditions accurately, this model, however, does not work for a vessel at non- zero relative water speed. This paper derives a large signal dynamic model of propeller that includes the...

  17. Utilizing Solar Power Technologies for On-Orbit Propellant Production

    Science.gov (United States)

    Fikes, John C.; Howell, Joe T.; Henley, Mark W.

    2006-01-01

    The cost of access to space beyond low Earth orbit may be reduced if vehicles can refuel in orbit. The cost of access to low Earth orbit may also be reduced by launching oxygen and hydrogen propellants in the form of water. To achieve this reduction in costs of access to low Earth orbit and beyond, a propellant depot is considered that electrolyzes water in orbit, then condenses and stores cryogenic oxygen and hydrogen. Power requirements for such a depot require Solar Power Satellite technologies. A propellant depot utilizing solar power technologies is discussed in this paper. The depot will be deployed in a 400 km circular equatorial orbit. It receives tanks of water launched into a lower orbit from Earth, converts the water to liquid hydrogen and oxygen, and stores up to 500 metric tons of cryogenic propellants. This requires a power system that is comparable to a large Solar Power Satellite capable of several 100 kW of energy. Power is supplied by a pair of solar arrays mounted perpendicular to the orbital plane, which rotates once per orbit to track the Sun. The majority of the power is used to run the electrolysis system. Thermal control is maintained by body-mounted radiators; these also provide some shielding against orbital debris. The propellant stored in the depot can support transportation from low Earth orbit to geostationary Earth orbit, the Moon, LaGrange points, Mars, etc. Emphasis is placed on the Water-Ice to Cryogen propellant production facility. A very high power system is required for cracking (electrolyzing) the water and condensing and refrigerating the resulting oxygen and hydrogen. For a propellant production rate of 500 metric tons (1,100,000 pounds) per year, an average electrical power supply of 100 s of kW is required. To make the most efficient use of space solar power, electrolysis is performed only during the portion of the orbit that the Depot is in sunlight, so roughly twice this power level is needed for operations in sunlight

  18. Analysis and test for space shuttle propellant dynamics

    Science.gov (United States)

    Berry, R. L.; Demchak, L. J.; Tegart, J. R.

    1983-01-01

    This report presents the results of a study to develop an analytical model capable of predicting the dynamic interaction forces on the Shuttle External Tank, due to large amplitude propellant slosh during RTLS separation. The report details low-g drop tower and KC-135 test programs that were conducted to investigate propellant reorientation during RTLS. In addition, the development of a nonlinear finite element slosh model (LAMPS2, two dimensional, and one LAMPS3, three dimensional) is presented. Correlation between the model and test data is presented as a verification of the modeling approach.

  19. Prediction of Non-Cavitation Propeller Noise in Time Domain

    Institute of Scientific and Technical Information of China (English)

    YE Jin-ming; XIONG Ying; XIAO Chang-run; BI Yi

    2011-01-01

    The blade frequency noise of non-cavitation propeller in a uniform flow is analyzed in time domain.The unsteady loading (dipole source) on the blade surface is calculated by a potential-based surface panel method.Then the timedependent pressure data is used as the input for Ffowcs Williams-Hawkings formulation to predict the acoustics pressure.The integration of noise source is performed over the true blade surface rather than the nothickness blade surface,and the effect of hub can be considered.The noise characteristics of the non-cavitation propeller and the numerical discretization forms are discussed.

  20. Cryogenic propellant management: Integration of design, performance and operational requirements

    Science.gov (United States)

    Worlund, A. L.; Jamieson, J. R., Jr.; Cole, T. W.; Lak, T. I.

    1985-01-01

    The integration of the design features of the Shuttle elements into a cryogenic propellant management system is described. The implementation and verification of the design/operational changes resulting from design deficiencies and/or element incompatibilities encountered subsequent to the critical design reviews are emphasized. Major topics include: subsystem designs to provide liquid oxygen (LO2) tank pressure stabilization, LO2 facility vent for ice prevention, liquid hydrogen (LH2) feedline high point bleed, pogo suppression on the Space Shuttle Main Engine (SSME), LO2 low level cutoff, Orbiter/engine propellant dump, and LO2 main feedline helium injection for geyser prevention.

  1. Flexible Screen Propellant Management Device for Near Term In-Space Demonstration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — While evaluating lunar ascent and descent stage propellant acquisition options in 2008 and 2009 for NASA GRC, IES conceived a novel, flexible screen propellant...

  2. Four-quadrant propeller modeling: A low-order harmonic approximation

    Digital Repository Service at National Institute of Oceanography (India)

    Haeusler, A.J.; Saccon, A.; Hauser, J.; Pascoal, A.M.; Aguiar, A.P.

    . We explore the connection between the propeller thrust, torque, and efficiency curves and the lift and drag curves of the propeller blades. The model originates from a well-known four-quadrant model, based on a sinusoidal approximation...

  3. Cavitation erosion in blocked flow with a ducted ice-class propeller

    Energy Technology Data Exchange (ETDEWEB)

    Doucet, J.M.; Bose, N.; Walker, D. [Memorial Univ. of Newfoundland, St. John`s, Newfoundland (Canada). Ocean Engineering Research Centre; Jones, S.J. [National Research Council of Canada, St. John`s, Newfoundland (Canada). Inst. for Marine Dynamics

    1996-12-31

    Ships that operate in ice often encounter momentary increased propeller cavitation because ice pieces block the flow into the propeller. For ducted propellers, this additional cavitation is more significant than it is for open propellers; ice pieces may become lodged against and within the duct and subject the propeller to longer periods of increased cavitation due to the blocked flow. Associated with this blocked flow is the possibility of cavitation erosion on the propeller. An erosion study, using paint films, was conducted in a cavitation tunnel with a model propeller of the type fitted to the Canadian Marine Drilling Ltd. vessel MV Robert LeMeur. A simulated ice blockage was installed ahead of the propeller model and within the duct. Tests were carried out over a range of advance coefficients for various test conditions. The resulting types of cavitation were documented, the erosion patterns were photographed and comparisons between each test were made.

  4. Double beta decay experiments

    International Nuclear Information System (INIS)

    The great sensitivity of double beta decay to neutrino mass and right handed currents has motivated many new and exciting attempts to observe this elusive nuclear phenomenon directly. Experiments in operation and other coming on line in the next one or two years are expected to result in order-of-magnitude improvements in detectable half lives for both the two-neutrino and no-neutrino modes. A brief history of double beta decay experiments is presented together with a discussion of current experimental efforts, including a gas filled time projection chamber being used to study selenium-82. (author)

  5. Plasma beta HCG determination

    International Nuclear Information System (INIS)

    There are three important indications for the early diagnosis of pregnancy through the determination of the beta sub-unit of chorionic gonadotrophin using radioimmunoassay: 1) some patient's or doctor's anxiety to discover the problem; 2) when it will be necessary to employ diagnostic or treatment procedures susceptible to affect the ovum; and 3) in the differential diagnosis of amenorrhoea, uterine hemorrhage and abdominal tumors. Other user's are the diagnosis of missed absortion, and the diagnosis and follow-up of chrorioncarcinoma. The AA. studied 200 determinations of plasma beta-HCG, considering the main difficulties occuring in the clinical use of this relevant laboratory tool in actual Obstetrics. (author)

  6. Beta and Gamma Gradients

    DEFF Research Database (Denmark)

    Løvborg, Leif; Gaffney, C. F.; Clark, P. A.;

    1985-01-01

    Experimental and/or theoretical estimates are presented concerning, (i) attenuation within the sample of beta and gamma radiation from the soil, (ii) the gamma dose within the sample due to its own radioactivity, and (iii) the soil gamma dose in the proximity of boundaries between regions of...... differing radioactivity. It is confirmed that removal of the outer 2 mm of sample is adequate to remove influence from soil beta dose and estimates are made of the error introduced by non-removal. Other evaluations include variation of the soil gamma dose near the ground surface and it appears that the...

  7. Impact of Advanced Propeller Technology on Aircraft/Mission Characteristics of Several General Aviation Aircraft

    Science.gov (United States)

    Keiter, I. D.

    1982-01-01

    Studies of several General Aviation aircraft indicated that the application of advanced technologies to General Aviation propellers can reduce fuel consumption in future aircraft by a significant amount. Propeller blade weight reductions achieved through the use of composites, propeller efficiency and noise improvements achieved through the use of advanced concepts and improved propeller analytical design methods result in aircraft with lower operating cost, acquisition cost and gross weight.

  8. A Review on Decomposition Deflagration of Oxidizer and Binders in Composite Solid Propellants

    Directory of Open Access Journals (Sweden)

    K. Kishore

    1979-01-01

    Full Text Available Binder and oxidizer decomposition play very significant role during the combustion of composite solid propellants. Ammonium perchlorate (AP is the practical oxidizer in composite propellant formulations. Available information on binder decomposition in general and AP decomposition in particular have been collected and reviewed from the viewpoint of their application in propellants. This review may be useful in understanding the mechanism of propellant combustion.

  9. Enantioselective synthesis of aziridines using asymmetric transfer hydrogenation as a precursor for chiral derivatives used as bonding agent for rocket solid propellants

    Directory of Open Access Journals (Sweden)

    Aparecida M. Kawamoto

    2002-11-01

    Full Text Available A rapid, expedient and enantioselective method for the synthesis of beta-hydroxy amines and monosubstituted aziridines in up to 99% e.e., via asymmetric transfer hydrogenation of a-amino ketones and cyclisation through treatment with tosyl chloride and base, is described. (1R,2R-N-(para-toluenesulfonyl-1,2-ethylenediamine with formic acid has been utilised as a ligand for the Ruthenium (II catalysed enantioselective transfer hydrogenation of the ketones.The chiral 2-methyl aziridine, which is a potentially more efficient bonding agent for Rocket Solid Propellant has been successfully achieved.

  10. Experimental set-up and results of the process of co-extruded perforated gun propellants

    NARCIS (Netherlands)

    Zebregs, M.; Driel, C.A. van

    2009-01-01

    Enhancement of gun performance can be obtained by increasing the propellant loading density or the energy content of the propellant. Serious consequences of these options are difficulties with regard to ignition and to gun barrel wear. Application of co-layered propellants is a good alternative, sin

  11. Flyer impact experiment to study vulnerability and reactivity of gun propellant formulations

    NARCIS (Netherlands)

    Bouma, R.H.B.; Boluijt, A.G.; Verbeek, H.J.

    2009-01-01

    A flyer impact experiment to study the vulnerability of propellant formulations is designed. The shock wave conditions of the impacting flyer are related to the energy transfer from a single detonating propellant grain as found by numerical simulation. A propellant will react due to the imposed shoc

  12. 14 CFR 35.42 - Components of the propeller control system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Components of the propeller control system. 35.42 Section 35.42 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.42 Components of the propeller control system. The applicant...

  13. Effect of gamma radiation on properties of a composite rocket propellant

    International Nuclear Information System (INIS)

    Gamma radiation was employed for modifying the properties of a composite rocket propellant prepared in a standard way. It was observed that when the same gamma dose was imparted to hydroxy terminated polybutadiene (HTPB) then converted into propellant, the enhancement in the properties was much larger than the irradiated propellant samples. (author)

  14. Evaluation of neutrino masses from $m_{\\beta\\beta}$ values

    CERN Document Server

    Khrushchov, V V

    2008-01-01

    A neutrino mass matrix is considered under conditions of the CP invariance and the negligible reactor mixing $\\theta_{13}$ angle. Absolute mass values for three neutrinos are evaluated in normal and inverted hierarchy spectra on the ground of data for oscillation mixing neutrino parameters and effective neutrino mass entering into a probability of neutrinoless two beta decay $m_{\\beta\\beta}$ values.

  15. Low-beta structures

    OpenAIRE

    M. Vretenar(CERN, Geneva, Switzerland)

    2012-01-01

    'Low-beta' radio-frequency accelerating structures are used in the sections of a linear accelerator where the velocity of the particle beam increases with energy. The requirement for space periodicity to match the increasing particle velocity led to the development of a large variety of structures, both normal and superconducting, which are described in this lecture.

  16. Applied Beta Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Rich, B.L.

    1986-01-01

    Measurements of beta and/or nonpenetrating exposure results is complicated and past techniques and capabilities have resulted in significant inaccuracies in recorded results. Current developments have resulted in increased capabilities which make the results more accurate and should result in less total exposure to the work force. Continued development of works in progress should provide equivalent future improvements.

  17. Roughing up Beta

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Li, Sophia Zhengzi; Todorov, Viktor

    Motivated by the implications from a stylized equilibrium pricing framework, we investigate empirically how individual equity prices respond to continuous, or \\smooth," and jumpy, or \\rough," market price moves, and how these different market price risks, or betas, are priced in the cross-section...

  18. Neutrinoless Double Beta Decay

    CERN Document Server

    Päs, Heinrich

    2015-01-01

    We review the potential to probe new physics with neutrinoless double beta decay $(A,Z) \\to (A,Z+2) + 2 e^-$. Both the standard long-range light neutrino mechanism as well as short-range mechanisms mediated by heavy particles are discussed. We also stress aspects of the connection to lepton number violation at colliders and the implications for baryogenesis.

  19. Applied Beta Dosimetry

    International Nuclear Information System (INIS)

    Measurements of beta and/or nonpenetrating exposure results is complicated and past techniques and capabilities have resulted in significant inaccuracies in recorded results. Current developments have resulted in increased capabilities which make the results more accurate and should result in less total exposure to the work force. Continued development of works in progress should provide equivalent future improvements

  20. Interferon Beta-1b Injection

    Science.gov (United States)

    Interferon beta-1b injection is used to reduce episodes of symptoms in patients with relapsing-remitting (course ... and problems with vision, speech, and bladder control). Interferon beta-1b is in a class of medications ...

  1. Genetics Home Reference: beta thalassemia

    Science.gov (United States)

    ... for Disease Control and Prevention Centre for Genetics Education (Australia) Cold Spring Harbor Laboratory: Your Genes Your Health Disease InfoSearch: Beta Thalassemia Genomics Education Programme (UK) MalaCards: dominant beta-thalassemia Merck Manual ...

  2. Transportation of Nanoscale Cargoes by Myosin Propelled Actin Filaments

    NARCIS (Netherlands)

    Persson, Malin; Gullberg, Maria; Tolf, Conny; Lindberg, A. Michael; Mansson, Alf; Kocer, Armagan

    2013-01-01

    Myosin II propelled actin filaments move ten times faster than kinesin driven microtubules and are thus attractive candidates as cargo-transporting shuttles in motor driven lab-on-a-chip devices. In addition, actomyosin-based transportation of nanoparticles is useful in various fundamental studies.

  3. How Mathematics Propels the Development of Physical Knowledge

    Science.gov (United States)

    Schwartz, Daniel L.; Martin, Taylor; Pfaffman, Jay

    2005-01-01

    Three studies examined whether mathematics can propel the development of physical understanding. In Experiment 1, 10-year-olds solved balance scale problems that used easy-to-count discrete quantities or hard-to-count continuous quantities. Discrete quantities led to age typical performances. Continuous quantities caused performances like those of…

  4. 14 CFR 21.500 - Approval of engines and propellers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Approval of engines and propellers. 21.500 Section 21.500 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... been subjected by the manufacturer to a final operational check....

  5. Hall-Effect Thruster Utilizing Bismuth as Propellant

    Science.gov (United States)

    Szabo, James; Gasdaska, Charles; Hruby, Vlad; Robin, Mike

    2008-01-01

    A laboratory-model Hall-effect spacecraft thruster was developed that utilizes bismuth as the propellant. Xenon was used in most prior Hall-effect thrusters. Bismuth is an attractive alternative because it has a larger atomic mass, a larger electron-impact-ionization cross-section, and is cheaper and more plentiful.

  6. Wear and Friction in a Controllable Pitch Propeller

    NARCIS (Netherlands)

    Godjevac, M.

    2010-01-01

    The author is a naval architect and this book is his PhD thesis. In this research the author focuses on friction in a controllable pitch propeller (CPP), formation of wear in a CPP system, and their mutual dependence. Instead of going deeply only in tribology aspects, the author tries to get an over

  7. PIV-based load determination in aircraft propellers

    NARCIS (Netherlands)

    Ragni, D.

    2012-01-01

    The thesis describes the application of particle image velocimetry (PIV) to study the aerodynamic loads of airfoils and aircraft propellers. The experimental work focuses on the development of a measurement procedure to infer the pressure of the flow field from the velocity distribution obtained by

  8. In-situ tensile testing of propellant samples within SEM

    NARCIS (Netherlands)

    Benedetto, G.L. di; Ramshorst, M.C.J. van; Duvalois, W.; Hooijmeijer, P.A.; Heijden, A.E.D.M. van der; Klerk, W.P.C. de

    2015-01-01

    A tensile module system placed within a FEI NovaNanoSEM 650 Scanning Electron Microscope (SEM) was utilized in this work to conduct in-situ tensile testing of propellant material samples. This tensile module system allows for real-time in-situ SEM analysis of the samples to determine the failure mec

  9. Combustion Characteristics of Coated Nano Aluminum in Composite Propellants

    Directory of Open Access Journals (Sweden)

    Yunlan Sun

    2006-10-01

    Full Text Available The effects of coated nano-sized aluminum (Al powder (n-Al and micron-sized Al powder(g-Al in propellants on the burning rate and pressure exponent have been investigated. Theresults show that the burning rates of propellants increase as the n-Al content increases, butthe burning rate pressure exponents tend to decrease. Compared with propellant containing-Al, the increments of burning rates of propellants containing n-Al powder reduce graduallywith increase in the pressure because of the differences of the combustion characteristics andignition performances of n-Al powder and g-Al powder. Single short distance photograph, scanningelectron microscopy, x-ray fluorescence analysis were used to characterise the flame image,combustion phenomena, the quenched surface image, and surface elements. A substantialdifference in combustion characteristics of n-Al powder has been found in comparison with-Al powder. In addition, oxygen-bomb combustion heat, ignition temperature, and recoveryratio of residues were measured.

  10. Developments on HNF based high performance and green solid propellants

    NARCIS (Netherlands)

    Keizers, H.L.J.; Heijden, A.E.D.M. van der; Vliet, L.D. van; Welland-Veltmans, W.H.M.; Ciucci, A.

    2001-01-01

    Worldwide developments are ongoing to develop new and more energetic composite solid propellant formulations for space transportation and military applications. Since the 90's, the use of HNF as a new high performance oxidiser is being reinvestigated. Within European development programmes, signific

  11. Characterization of ADN and ADN-Based propellants

    Energy Technology Data Exchange (ETDEWEB)

    Jones, David E.G.; Kwok, Queenie S.M.; Vachon, Marie; Badeen, Christopher; Ridley, William [Canadian Explosives Research Laboratory, 555 Booth St., Ottawa, Ontario K1A 0G1 (Canada)

    2005-04-01

    Ammonium dinitramide (ADN), NH{sub 4}N(NO{sub 2}){sub 2} is being considered as one of the potential new energetic oxidizers for composite propellants. In this study, ADN crystals, prills and two ADN-based propellants having different relative amounts of ingredients were characterized. The concentration of the crystals and the prills samples was determined using ion chromatography. The thermal behavior of the crystals, prills and propellants was studied using DSC, simultaneous TG-DTA-FTIR-MS, ARC (accelerating rate calorimeter), HFC (heat flux calorimeter) and INC (isothermal nanocalorimeter). Decomposition of ADN was observed from all of the samples at temperatures above the melting point of ADN (92 C). Formation of N{sub 2}O, NO{sub 2}, H{sub 2}O, CO{sub 2}, CO, N{sub 2} and NO was detected during the ADN decomposition. The thermal stability of the ADN samples at temperatures below the melting point of ADN was studied. Early solid decomposition of ADN, which generates N{sub 2}O and H{sub 2}O, was observed at 60 C. Electrostatic discharge (ESD) and impact sensitivity of the ADN samples were determined. The crystals and prills are sensitive to impact, while the two propellants are relatively less ESD and impact sensitive. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  12. The ways for development of environmentally safe solid composite propellants

    Science.gov (United States)

    Lempert, D. B.; Manelis, G. B.; Nechiporenko, G. N.

    2009-09-01

    The paper considers a wide set of issues concerning the creation of high energetic solid composite propellants causing the minimal polluting effect on the environment. Thereby, the level of toxicity of products of different compositions is discussed and propellants with perchlorates oxidizers are compared with propellants with halogen free oxidizers (mainly, ammonium dinitramide, HMX, CL-20). The main methods for creating compositions having a required performance and the highest energetic characteristics are also under discussion. The dependences of the specific impulse on the mode of formulation arrangement and on the compounds' properties (i.e., formation enthalpy, density, element content) are demonstrated. The main principles for the maximal use of energetic potential of chemical substances are under consideration. These are the proper selection of the binder type which would be optimal for the given mixture of oxidizer with fuel (or energetic) component and the opportunity of using metals and their hydrides (mainly, aluminum hydride (AH)). Main obstacles in using different kinds of compositions, as well as advantages of specific propellants are under consideration as well. A special attention is paid to the interrelationship between the energetic parameter and other performances (thermal stability, combustion law, sensitivity, and compatibility).

  13. Natural Rubber Based Fuel Rich Propellant for Ramjet Rocket

    Directory of Open Access Journals (Sweden)

    Solomon Thomas

    1992-07-01

    Full Text Available Development of fuel rich propellants for air-breathing propulsion is one of the frontier areas of research. This carries less oxidiser than the normal propellants, uses ram air for complete combustion and is heavily metallised. Studies were conducted at VSSC for the development of hydroxyl-terminated natural rubber (HTNR-based Mg and Mg-Al alloy-filled polyurethane systems. The HTNR prepolymer was modified to make it free of acid functionality so as to avoid reaction with the metals and was then reacted with calculated amount of propylene oxide in the presence of tertiary amine catalyst at room temperature. Various levels of Mg and Mg-Al alloy were used in different compositions and the effect on propellant characteristics was studied. TMP and butane diol were used for higher crosslinking, chain extension, etc and their effects were evaluated. Propellant compositions using 30-35 per cent by weight of Mg/Mg-Al alloy with the modified prepolymer have been developed. They exhibit good processibility and mechanical properties. The feasibility of room temperature curing was attempted. Motors weighing 2 kg with 100 mm OD and 200 mm length were successfully static-tested in the primary mode for performance evaluation.

  14. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch controls. 23.1149 Section 23.1149 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Powerplant Controls and Accessories...

  15. 14 CFR 125.123 - Propeller deicing fluid.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Propeller deicing fluid. 125.123 Section 125.123 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS CERTIFICATION AND OPERATIONS: AIRPLANES HAVING A SEATING...

  16. 14 CFR 121.225 - Propeller deicing fluid.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Propeller deicing fluid. 121.225 Section 121.225 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND...

  17. Statistics of Neutron Stars at the Stage of Supersonic Propeller

    CERN Document Server

    Beskin, V S

    2005-01-01

    We analyze the statistical distribution of neutron stars at the stage of a supersonic propeller. An important point of our analysis is allowance for the evolution of the angle of inclination of the magnetic axis to the spin axis of the neutron star for the boundary of the transition to the supersonic propeller stage for two models: the model with hindered particle escape from the stellar surface and the model with free particle escape. As a result, we have shown that a consistent allowance for the evolution of the inclination angle in the region of extinct radio pulsars for the two models leads to an increase in the total number of neutron stars at the supersonic propeller stage. This increase stems from he fact that when allowing for the evolution of the inclination angle $\\chi$ for neutron stars in the region of extinct radio pulsars and, hence, for the boundary of the transition to the propeller stage, this transition is possible at shorter spin periods (P~5-10 s) than assumed in the standard model.

  18. "Propeller" Regime of Disk Accretion to Rapidly Rotating Stars

    CERN Document Server

    Ustyugova, G V; Lovelace, R V E; Romanova, M M

    2006-01-01

    We present results of axisymmetic magnetohydrodynamic simulations of the interaction of a rapidly-rotating, magnetized star with an accretion disk. The disk is considered to have a finite viscosity and magnetic diffusivity. The main parameters of the system are the star's angular velocity and magnetic moment, and the disk's viscosity, diffusivity. We focus on the "propeller" regime where the inner radius of the disk is larger than the corotation radius. Two types of magnetohydrodynamic flows have been found as a result of simulations: "weak" and "strong" propellers. The strong propeller is characterized by a powerful disk wind and a collimated magnetically dominated outflow or jet from the star. The weak propeller have only weak outflows. We investigated the time-averaged characteristics of the interaction between the main elements of the system, the star, the disk, the wind from the disk, and the jet. Rates of exchange of mass and angular momentum between the elements of the system are derived as a function ...

  19. Turbulent viscosity variability in self-propelled body wake model

    CERN Document Server

    Dubrovin, K; Golbraikh, E; Soloviev, A

    2011-01-01

    We study the influence of turbulent viscosity variability on the properties of self-propelled body wake model. In addition to the already known integrals of motion obtained with constant turbulent viscosity, we obtain new ones. The presence of new integrals of motion leads, in particular, to changes in the behavior of the width and profile of the wake leading to its conservation.

  20. 14 CFR 23.1153 - Propeller feathering controls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller feathering controls. 23.1153 Section 23.1153 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Powerplant Controls and Accessories §...

  1. Optimization and performance calculation of dual-rotation propellers

    Science.gov (United States)

    Davidson, R. E.

    1981-01-01

    An analysis is given which enables the design of dual-rotation propellers. It relies on the use of a new tip loss factor deduced from T. Theodorsen's measurements coupled with the general methodology of C. N. H. Lock. In addition, it includes the effect of drag in optimizing. Some values for the tip loss factor are calculated for one advance ratio.

  2. Numerical analysis for cavitation flow of marine propeller

    Science.gov (United States)

    Tauviqirrahman, Mohammad; Muchammad, Ismail, Rifky; Jamari, J.

    2015-12-01

    Concerning the environmental issue and the increase of fuel price, optimizing the fuel consumption has been recently an important subject in all industries. In marine industries one of the ways to decrease the energy consumption was by reducing the presence of cavitation on marine propeller blades. This will give a higher propulsive efficiency. This paper provides an investigation into the influence of the cavitation on a hydrodynamic performance around the propeller based on numerical method. Hydrofoil representing the blade form of propeller was of particular of interest. Two types of cavitation model were investigated with respect to the accuracy of the result and the effectiveness of the method. The results include the hydrodynamic characteristics of cavitation phenomenon like lift/drag variation with respect to the cavity extent. It was found that a high accuracy and low computational time is achieved when the cavitation model of Zwart-Gerber-Belamri is used. The interesting outcome of this study is that the results can be used as a good evaluation tool for high marine propeller performance.

  3. Glycidyl Azide Polymer-based Enhanced Energy LOVA Gun Propellant

    OpenAIRE

    R. R. Sanghavi; P. J. Kamale; M.A.R. Shaikh; T. K. Chakraborthy; S. N. Asthana; Amarjit Singh

    2006-01-01

    In this study, cyclotrimethylene trinitramine propellants with triacetin (TA)-plasticisedcellulose acetate (CA) and nitrocellulose (NC) combination as binders were evaluated for lowvulnerable ammunition (LOVA). Triacetin was replaced by energetic plasticiser; glycidyl azidepolymer (GAP) in increments to enhance the performance in terms of force constant . In additionto ballistics, parameters like vulnerability, mechanical and thermal properties of GAP-basedpropellants in comparison to those o...

  4. The experimental characterization of particle dynamics in solid composite propellants

    Science.gov (United States)

    Moore, Joseph Elijah

    There are many parameters affecting the size and behavior of aluminum (Al) droplets on and near the burning surface of composite solid propellants. Multiple points of view are studied in the current investigation. The first is in the development of a Statistical Image Correlation Velocimeter (SICV) to analyze the velocity of exhaust particles and gases leaving the burning surface. Many of the analysis techniques used in the validation of the SICV software are then used to conduct further analysis including additional propellants. The next portion of the study looks at the effect of changing two of the formulation parameters in the propellant: the metal fuel content, and the polymer binder composition. Al/Nickel (Ni) clad particles are used as an additive to the conventional Al powder. Titanium-Boron (Ti-B) is also studied as another potential intermetallic additive. The nature of the binder is studied by examining the differences between propellants made with hydroxyl-terminated polybutadiene (HTPB) and dicyclopentadiene (DCPD) binders. Strand burns are conducted in the open atmosphere as well as in a windowed combustion vessel at pressures ranging from atmospheric to 700 psig. The burning surface linear regression rate, as well as size of the agglomerated metal fuel particles leaving the surface is measured using macro- and microscopic high speed imaging followed by video analysis using modeling tools and digital particle sizing algorithms. It is shown that the partial replacement of Al with Al/Ni clad particles decreases the average size of the agglomerated particles and increases the propellant burning rate. An optimum fraction likely exists. It is also shown that ball milling, or mechanical activation, of the Al/Ni particles leads to a further increase in the burning rate of the propellant. This is likely due to a decrease in the ignition temperature of the material after it has undergone mechanical activation. Analysis of binder-specific samples reveals that

  5. Viscoelastic Modelling of Solid Rocket Propellants using Maxwell Fluid Model

    Directory of Open Access Journals (Sweden)

    Himanshu Shekhar

    2010-07-01

    Full Text Available Maxwell fluid model consisting of a spring and a dashpot in series is applied for viscoelastic characterisation of solid rocket propellants. Suitable values of spring constant and damping coefficient wereemployed by least square variation of errors for generation of complete stress-strain curve in uniaxial tensile mode for case-bonded solid propellant formulations. Propellants from the same lot were tested at different strain rates. It was observed that change in spring constant, representing elastic part was very small with strain rate but damping constant varies significantly with variation in strain rate. For a typical propellant formulation, when strain rate was raised from 0.00037/s to 0.185/s, spring constant K changed from 5.5 MPato 7.9 MPa, but damping coefficient D was reduced from 1400 MPa-s to 4 MPa-s. For all strain rates, stress-strain curve was generated using Maxwell model and close matching with actual test curve was observed.This indicates validity of Maxwell fluid model for uniaxial tensile testing curves of case-bonded solid propellant formulations. It was established that at higher strain rate, damping coefficient becomes negligible as compared to spring constant. It was also observed that variation of spring constant is logarithmic with strain rate and that of damping coefficient follows power law. The correlation coefficients were introduced to ascertain spring constants and damping coefficients at any strain rate from that at a reference strain rate. Correlationfor spring constant needs a coefficient H, which is function of propellant formulation alone and not of test conditions and the equation developeds K2 = K1 + H ´ ln{(de2/dt/(de1/dt}. Similarly for damping coefficient D also another constant S is introduced and prediction formula is given by D2 = D1 ´ {(de2/dt/(de1/dt}S.Evaluating constants H and S at different strain rates validate this mathematical formulation for differentpropellant formulations

  6. Beta gets better with age

    OpenAIRE

    Tomunen, Tuomas

    2015-01-01

    The objective of my thesis is to study the cause for the low beta anomaly, which is an observation that the high beta stocks perform poorly relative to the low beta stocks. Based on earlier findings, I hypothesize that if a stock has high investor attention, its price overreacts to market-wide shocks, which results in a positive measurement error in its beta. Simultaneously, high attention causes overpricing, because the stock overreacts more often to positive shocks than to negat...

  7. Misleading Betas: An Educational Example

    Science.gov (United States)

    Chong, James; Halcoussis, Dennis; Phillips, G. Michael

    2012-01-01

    The dual-beta model is a generalization of the CAPM model. In the dual-beta model, separate beta estimates are provided for up-market and down-market days. This paper uses the historical "Anscombe quartet" results which illustrated how very different datasets can produce the same regression coefficients to motivate a discussion of the…

  8. Cleanup/stimulation of a horizontal wellbore using propellants

    Energy Technology Data Exchange (ETDEWEB)

    Rougeot, J.E.; Lauterbach, K.A.

    1993-01-01

    This report documents the stimulation/cleanup of a horizontal well bore (Wilson 25) using propellants. The Wilson 25 is a Bartlesville Sand well located in the Flatrock Field, Osage County, Oklahoma. The Wilson 25 was drilled to determine if horizontal drilling could be used as a means to economically recover primary oil that had been left in place in a mostly abandoned oil field because of the adverse effects of water coning. Pump testing of the Wilson 25 horizontal well bore before cleanup or stimulation produced 6 barrels of oil and .84 barrels of water per day. The high percentage of daily oil production to total daily fluid production indicated that the horizontal well bore had accessed potentially economical oil reserves if the fluid production rate could be increased by performing a cleanup/stimulation treatment. Propellants were selected as an inexpensive means to stimulate and cleanup the near well bore area in a uniform manner. The ignition of a propellant creates a large volume of gas which penetrates the formation, creating numerous short cracks through which hydrocarbons can travel into the well bore. More conventional stimulation/cleanup techniques were either significantly more expensive, less likely to treat uniformly, or could not be confined to the near well bore area. Three different propellant torpedo designs were tested with a total of 304' of horizontal well bore being shot and producible. The initial test shot caused 400' of the horizontal well bore to become plugged off, and subsequently it could not be production tested. The second and third test shots were production tested, with the oil production being increased 458% and 349%, respectively, on a per foot basis. The Wilson 25 results indicate that a propellant shot treatment is an economically viable means to cleanup/stimulate a horizontal well bore.

  9. The analysis of random effects regression model for predicting the shelf-life of gun propellant

    OpenAIRE

    Chang, Wei-Te

    1995-01-01

    Most gun propellant is stored at depots for a long time before it is used. While being stored, the quality of the gun propellant may deteriorate and become unstable. In an attempt to avoid disaster due to use of unstable gun propellant, accurate prediction of the safe shelf-life of gun propellant is necessary. The shelf-life estimation methods used currently for a group of similar gun propellant lots are based on a fixed effects regression model. This does not take into consideration the fact...

  10. Modeling the effects of wind tunnel wall absorption on the acoustic radiation characteristics of propellers

    Science.gov (United States)

    Baumeister, K. J.; Eversman, W.

    1986-01-01

    Finite element theory is used to calculate the acoustic field of a propeller in a soft walled circular wind tunnel and to compare the radiation patterns to the same propeller in free space. Parametric solutions are present for a 'Gutin' propeller for a variety of flow Mach numbers, admittance values at the wall, microphone position locations, and propeller to duct radius ratios. Wind tunnel boundary layer is not included in this analysis. For wall admittance nearly equal to the characteristic value of free space, the free field and ducted propeller models agree in pressure level and directionality. In addition, the need for experimentally mapping the acoustic field is discussed.

  11. Investigation on the wake evolution of contra-rotating propeller using RANS computation and SPIV measurement

    Science.gov (United States)

    Paik, Kwang-Jun; Hwang, Seunghyun; Jung, Jaekwon; Lee, Taegu; Lee, Yeong-Yeon; Ahn, Haeseong; Van, Suak-Ho

    2015-09-01

    The wake characteristics of Contra-Rotating Propeller (CRP) were investigated using numerical simulation and flow measurement. The numerical simulation was carried out with a commercial CFD code based on a Reynolds Averaged Navier-Stokes (RANS) equations solver, and the flow measurement was performed with Stereoscopic Particle Image Velocimetry (SPIV) system. The simulation results were validated through the comparison with the experiment results measured around the leading edge of rudder to investigate the effect of propeller operation under the conditions without propeller, with forward propeller alone, and with both forward and aft propellers. The evolution of CRP wake was analyzed through velocity and vorticity contours on three transverse planes and one longitudinal plane based on CFD results. The trajectories of propeller tip vortex core in the cases with and without aft propeller were also compared, and larger wake contraction with CRP was confirmed.

  12. Investigation on the foaming behaviors of NC-based gun propellants

    Directory of Open Access Journals (Sweden)

    Yu-xiang Li

    2014-09-01

    Full Text Available To prepare the porous NC-based (nitrocellulose-based gun propellants, the batch foaming process of using supercritical CO2 as the physical blowing agent is used. The solubilities of CO2 in the single-base propellants and TEGDN (trimethyleneglycol dinitrate propellants are measured by the gravimetric method, and SEM (scanning electron microscope is used to observe the morphology of foamed propellants. The result shows that a large amount of CO2 could be dissolved in NC-based propellants. The experimental results also reveal that the energetic plasticizer TEGDN exerts an important influence on the pore structure. The triaxial tensile failure mechanism for solid-state nucleation is used to explain the nucleation of NC-based propellants in the solid state. Since some specific foaming behaviors of NC-based propellants can not be explained by the failure mechanism, a solid-state nucleation mechanism which revises the triaxial tensile failure mechanism is proposed and discussed.

  13. Nonlinear Output Feedback Control of Underwater Vehicle Propellers using Advance Speed Feedback

    DEFF Research Database (Denmark)

    Fossen, T.I.; Blanke, M.

    1999-01-01

    More accurate propeller shaft speed controllers can be designed by using nonlinear control theory. In this paper, an output feedback controller reconstructing the advance speed (speed of water going into the propeller) from vehicle speed measurements is derived. For this purpose a three-state model...... of propeller shaft speed, forward (surge) speed of the vehicle and axial inlet flow of the propeller is applied. A nonlinear observer in combination with an output feedback integral controller are derived by applying Lyapunov stability theory and exponential stability is proven. The output feedback...... controller minimizes thruster losses due to variations in propeller axial inlet flow which is a major problem when applying conventional vehicle-propeller control systems. The proposed controller is simulated for an underwater vehicle equipped with a single propeller. From the simulations it can be concluded...

  14. A Consideration for Design of Ammonium Perchlorate/Hydroxyl Terminated Polybutadiene Composite Propellant

    Science.gov (United States)

    Kohga, Makoto

    Specific impulse and burning rate characteristics are the important properties for the propellant design. Because of the requirements for the preparation of ammonium perchlorate (AP)/hydroxyl-terminated polybutadiene (HTPB) composite propellant, there is an upper limit content, φ of AP contained propellant. Specific impulse and burning rate increase with increasing the AP content. The specific impulse, Ispφ and the burning rate, rφ of the propellant prepared at φ, rφ are the highest values of the propellant prepared with AP used as an oxidizer. It is necessary for the propellant design to estimate φ, Ispφ and rφ. The φ, Ispφ and rφ are closely associated with the specific surface area, Swp measured by air-permeability method. Therefore, these values are estimated with Swp. A process for the design of AP/HTPB composite propellant would be proposed in this study.

  15. High-Lift Propeller System Configuration Selection for NASA's SCEPTOR Distributed Electric Propulsion Flight Demonstrator

    Science.gov (United States)

    Patterson, Michael D.; Derlaga, Joseph M.; Borer, Nicholas K.

    2016-01-01

    Although the primary function of propellers is typically to produce thrust, aircraft equipped with distributed electric propulsion (DEP) may utilize propellers whose main purpose is to act as a form of high-lift device. These \\high-lift propellers" can be placed upstream of wing such that, when the higher-velocity ow in the propellers' slipstreams interacts with the wing, the lift is increased. This technique is a main design feature of a new NASA advanced design project called Scalable Convergent Electric Propulsion Technology Operations Research (SCEPTOR). The goal of the SCEPTOR project is design, build, and y a DEP aircraft to demonstrate that such an aircraft can be much more ecient than conventional designs. This paper provides details into the high-lift propeller system con guration selection for the SCEPTOR ight demonstrator. The methods used in the high-lift propeller system conceptual design and the tradeo s considered in selecting the number of propellers are discussed.

  16. Investigation on the wake evolution of contra-rotating propeller using RANS computation and SPIV measurement

    Directory of Open Access Journals (Sweden)

    Paik Kwang-Jun

    2015-05-01

    Full Text Available The wake characteristics of Contra-Rotating Propeller (CRP were investigated using numerical simulation and flow measurement. The numerical simulation was carried out with a commercial CFD code based on a Reynolds Averaged Navier-Stokes (RANS equations solver, and the flow measurement was performed with Stereoscopic Particle Image Velocimetry (SPIV system. The simulation results were validated through the comparison with the experiment results measured around the leading edge of rudder to investigate the effect of propeller operation under the conditions without propeller, with forward propeller alone, and with both forward and aft propellers. The evolution of CRP wake was analyzed through velocity and vorticity contours on three transverse planes and one longitudinal plane based on CFD results. The trajectories of propeller tip vortex core in the cases with and without aft propeller were also compared, and larger wake contraction with CRP was confirmed.

  17. Beta-thalassemia

    Directory of Open Access Journals (Sweden)

    Origa Raffaella

    2010-05-01

    Full Text Available Abstract Beta-thalassemias are a group of hereditary blood disorders characterized by anomalies in the synthesis of the beta chains of hemoglobin resulting in variable phenotypes ranging from severe anemia to clinically asymptomatic individuals. The total annual incidence of symptomatic individuals is estimated at 1 in 100,000 throughout the world and 1 in 10,000 people in the European Union. Three main forms have been described: thalassemia major, thalassemia intermedia and thalassemia minor. Individuals with thalassemia major usually present within the first two years of life with severe anemia, requiring regular red blood cell (RBC transfusions. Findings in untreated or poorly transfused individuals with thalassemia major, as seen in some developing countries, are growth retardation, pallor, jaundice, poor musculature, hepatosplenomegaly, leg ulcers, development of masses from extramedullary hematopoiesis, and skeletal changes that result from expansion of the bone marrow. Regular transfusion therapy leads to iron overload-related complications including endocrine complication (growth retardation, failure of sexual maturation, diabetes mellitus, and insufficiency of the parathyroid, thyroid, pituitary, and less commonly, adrenal glands, dilated myocardiopathy, liver fibrosis and cirrhosis. Patients with thalassemia intermedia present later in life with moderate anemia and do not require regular transfusions. Main clinical features in these patients are hypertrophy of erythroid marrow with medullary and extramedullary hematopoiesis and its complications (osteoporosis, masses of erythropoietic tissue that primarily affect the spleen, liver, lymph nodes, chest and spine, and bone deformities and typical facial changes, gallstones, painful leg ulcers and increased predisposition to thrombosis. Thalassemia minor is clinically asymptomatic but some subjects may have moderate anemia. Beta-thalassemias are caused by point mutations or, more rarely

  18. Beta and muon decays

    International Nuclear Information System (INIS)

    These notes represent a series of lectures delivered by the authors in the Junta de Energia Nuclear, during the Spring term of 1965. They were devoted to graduate students interested in the Theory of Elementary Particles. Special emphasis was focussed into the computational problems. Chapter I is a review of basic principles (Dirac equation, transition probabilities, final state interactions.) which will be needed later. In Chapter II the four-fermion punctual Interaction is discussed, Chapter III is devoted to the study of beta-decay; the main emphasis is given to the deduction of the formulae corresponding to electron-antineutrino correlation, electron energy spectrum, lifetimes, asymmetry of electrons emitted from polarized nuclei, electron and neutrino polarization and time reversal invariance in beta decay. In Chapter IV we deal with the decay of polarized muons with radiative corrections. Chapter V is devoted to an introduction to C.V.C. theory. (Author)

  19. Integration of BETA with Eclipse

    DEFF Research Database (Denmark)

    Andersen, Peter; Madsen, Ole Lehrmann; Enevoldsen, Mads Brøgger

    2004-01-01

    This paper presents language interoperability issues appearing in order to implement support for the BETA language in the Java-based Eclipse integrated development environment. One of the challenges is to implement plug-ins in BETA and be able to load them in Eclipse. In order to do this, some form...... of language interoperability between Java and BETA is required. The first approach is to use the Java Native Interface and use C to bridge between Java and BETA. This results in a workable, but complicated solution. The second approach is to let the BETA compiler generate Java class files. With this...... approach it is possible to implement plug-ins in BETA and even inherit from Java classes. In the paper the two approaches are described together with part of the mapping from BETA to Java class files. http://www.sciencedirect.com/science/journal/15710661...

  20. COM Support in BETA

    DEFF Research Database (Denmark)

    Madsen, Ole Lehrmann

    1999-01-01

    Component technologies based on binary units of independent production are some of the most important contributions to software architecture and reuse during recent years. Especially the COM technologies and the CORBA standard from the Object Management Group have contributed new and interesting ...... principles for software architecture, and proven to be useful in parctice. In this paper ongoing work with component support in the BETA language is described....

  1. Beta decay for pedestrians

    CERN Document Server

    Lipkin, Harry Jeannot

    1962-01-01

    The ""pedestrian approach"" was developed to describe some essentially simple experimental results and their theoretical implications in plain language. In this graduate-level text, Harry J. Lipkin presents simply, but without oversimplification, the aspects of beta decay that can be understood without reference to the formal theory; that is, the reactions that follow directly from conservation laws and elementary quantum mechanics.The pedestrian treatment is neither a substitute for a complete treatment nor a watered-down version.

  2. LHCb: $2\\beta_s$ measurement at LHCb

    CERN Multimedia

    Conti, G

    2009-01-01

    A measurement of $2\\beta_s$, the phase of the $B_s-\\bar{B_s}$ oscillation amplitude with respect to that of the ${\\rm b} \\rightarrow {\\rm c^{+}}{\\rm W^{-}}$ tree decay amplitude, is one of the key goals of the LHCb experiment with first data. In the Standard Model (SM), $2\\beta_s$ is predicted to be $0.0360^{+0.0020}_{-0.0016} \\rm rad$. The current constraints from the Tevatron are: $2\\beta_{s}\\in[0.32 ; 2.82]$ at 68$\\%$CL from the CDF experiment and $2\\beta_{s}=0.57^{+0.24}_{-0.30}$ from the D$\\oslash$ experiment. Although the statistical uncertainties are large, these results hint at the possible contribution of New Physics in the $B_s-\\bar{B_s}$ box diagram. After one year of data taking at LHCb at an average luminosity of $\\mathcal{L}\\sim2\\cdot10^{32}\\rm cm^{-2} \\rm s^{-1}$ (integrated luminosity $\\mathcal{L}_{\\rm int}\\sim 2 \\rm fb^{-1}$), the expected statistical uncertainty on the measurement is $\\sigma(2\\beta_s)\\simeq 0.03$. This uncertainty is similar to the $2\\beta_s$ value predicted by the SM.

  3. Demonstration of Oxygen and Carbon Monoxide Propellants for Mars Missions

    Science.gov (United States)

    Linne, Diane L.

    1997-01-01

    Currently, proposed planetary exploration missions must be small, with low costs and a short development time. Relatively high-risk technologies are being accepted for such missions if they meet these guidelines. For a Mars sample-return mission, one of the higher risk technologies is the use of return propellants produced from indigenous materials such as the Martian atmosphere. This consists of 96 percent carbon dioxide, which can be processed into oxygen and carbon monoxide. This year, the NASA Lewis Research Center completed the experimental evaluation and subscale technology development of an oxygen/carbon monoxide propellant combination. Previous research included ignition characterization, combustion performance, and heat transfer characterization with gaseous propellants at room temperature. In this year s tests, we studied the ignition characteristics and combustion of oxygen and carbon monoxide at near liquid temperatures. The mixture ratio boundaries for oxygen and carbon monoxide were determined as a function of propellant temperature in a spark torch igniter. With both propellants at room temperature, the ignition range was between 0.50 and 1.44; and with both propellants chilled to near-liquid temperatures, it was between 2.4 and 3.1. Statistical analysis of the mean value of the ignition boundaries provided models that describe the combination of oxygen temperature, carbon monoxide temperature, and mixture ratio that resulted in ignition. This range is the larger boxed area shown in the figure. The smaller boxed area indicates the range at which there is a 90-percent confidence that ignition will occur. The relatively small range at only 90-percent confidence indicates that using the oxygen/carbon monoxide combination as its own ignition source may not be the best design for a remote engine operating on Mars. Tests also were performed in a simulated small rocket engine that used oxygen/hydrogen combustion gases as the ignition source for oxygen

  4. Metallised Fuel rich Propellants for Solid Rocket Ramjet: A Review

    Directory of Open Access Journals (Sweden)

    B. K. Athawale

    1994-10-01

    Full Text Available This paper reviews the research work carried out in the field of metallised fuel-rich propellants (FRP. Limitations and merits of various potential metals (Al, Mg, B, Be, or Zr as a component of FRP are discussed. The paper also includes a discussion on the combustion mechanism of metallised propellants, including problem areas and probable remedial measures. Zirconium and Ti appear to have potential to offer FRP with efficient combustion. Ideal performance is not achieved with current systems based on Al and B and further work is needed to develop FRP having all three desirable attributes, viz., ease of ignition, stable combustion and high specific impulse (I/sub sp/ in a single composition.

  5. Peak Strain in Regressing Finocyl Port Propellant Grainsunder Pressure Loading

    Directory of Open Access Journals (Sweden)

    Himanshu Shekhar

    2007-03-01

    Full Text Available Finite element analysis (FEM has been conducted for case-bonded finocyl port propellantcross section under pressure loading conditions during burning. Peak strain is found todecrease in course of burning, hence, analysis of any intermediate configuration in courseof burning is not required for assessing margin of safety in finocyl port propellant grains.The Power Law proposed1 has also been used to predict peak strain. Variation in strainsobtained by FEM and using the Power Law is found to be matching closely with findingsreported in CPIA (Chemical Propulsion Information Agency publications. Extension indomain of power law to regressing pressurised finocyl port propellant grain eliminates dependenceon time-consuming computer- intensive FEM computations without compromising the accuracyof results.

  6. Nano and micro architectures for self-propelled motors

    International Nuclear Information System (INIS)

    Self-propelled micromotors are emerging as important tools that help us understand the fundamentals of motion at the microscale and the nanoscale. Development of the motors for various biomedical and environmental applications is being pursued. Multiple fabrication methods can be used to construct the geometries of different sizes of motors. Here, we present an overview of appropriate methods of fabrication according to both size and shape requirements and the concept of guiding the catalytic motors within the confines of wall. Micromotors have also been incorporated with biological systems for a new type of fabrication method for bioinspired hybrid motors using three-dimensional (3D) printing technology. The 3D printed hybrid and bioinspired motors can be propelled by using ultrasound or live cells, offering a more biocompatible approach when compared to traditional catalytic motors. (focus issue paper)

  7. Swarm behavior of self-propelled rods and swimming flagella

    CERN Document Server

    Yang, Yingzi; Gompper, Gerhard

    2010-01-01

    Systems of self-propelled particles are known for their tendency to aggregate and to display swarm behavior. We investigate two model systems, self-propelled rods interacting via volume exclusion, and sinusoidally-beating flagella embedded in a fluid with hydrodynamic interactions. In the flagella system, beating frequencies are Gaussian distributed with a non-zero average. These systems are studied by Brownian-dynamics simulations and by mesoscale hydrodynamics simulations, respectively. The clustering behavior is analyzed as the particle density and the environmental or internal noise are varied. By distinguishing three types of cluster-size probability density functions, we obtain a phase diagram of different swarm behaviors. The properties of clusters, such as their configuration, lifetime and average size are analyzed. We find that the swarm behavior of the two systems, characterized by several effective power laws, is very similar. However, a more careful analysis reveals several differences. Clusters o...

  8. Gravitaxis of asymmetric self-propelled colloidal particles

    Science.gov (United States)

    Ten Hagen, Borge; Kümmel, Felix; Wittkowski, Raphael; Takagi, Daisuke; Löwen, Hartmut; Bechinger, Clemens

    2014-09-01

    Many motile microorganisms adjust their swimming motion relative to the gravitational field and thus counteract sedimentation to the ground. This gravitactic behaviour is often the result of an inhomogeneous mass distribution, which aligns the microorganism similar to a buoy. However, it has been suggested that gravitaxis can also result from a geometric fore-rear asymmetry, typical for many self-propelling organisms. Despite several attempts, no conclusive evidence for such an asymmetry-induced gravitactic motion exists. Here, we study the motion of asymmetric self-propelled colloidal particles which have a homogeneous mass density and a well-defined shape. In experiments and by theoretical modelling, we demonstrate that a shape anisotropy alone is sufficient to induce gravitactic motion with either preferential upward or downward swimming. In addition, also trochoid-like trajectories transversal to the direction of gravity are observed.

  9. Optics and materials considerations for a laser-propelled lightsail

    Science.gov (United States)

    Landis, Geoffrey A.

    1989-01-01

    The principles of a laser-propelled lightsail for an interstellar probe are discussed. The feasibility of a laser-propelled-lightsail round-trip interstellar mission proposed by Forward (1984) is examined, with special attention given to the issues of optics and materials. It is shown that the large lens and a high lens/target distance required by such a mission result in optical difficulties, requiring positioning tolerance for the 1000-km-diam lens of only 3 m, which is unlikely to be achievable. Techniques and sail materials that would reduce this problem are suggested, including the use of LiF and CaF2 quarter-wave dielectric films and the use of many intermediate lenses spaced between the probe and the source. It is pointed out that, as sail materials, the quarter-wavelength dielectric films have significant advantages over metals.

  10. Liquid propellant analogy technique in dynamic modeling of launch vehicle

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The coupling effects among lateral mode,longitudinal mode and torsional mode of a launch vehicle cannot be taken into account in traditional dynamic analysis using lateral beam model and longitudinal spring-mass model individually.To deal with the problem,propellant analogy methods based on beam model are proposed and coupled mass-matrix of liquid propellant is constructed through additional mass in the present study.Then an integrated model of launch vehicle for free vibration analysis is established,by which research on the interactions between longitudinal and lateral modes,longitudinal and torsional modes of the launch vehicle can be implemented.Numerical examples for tandem tanks validate the present method and its necessity.

  11. Modelling of Heat Loss in Closed Vessels during propellant Burning

    Directory of Open Access Journals (Sweden)

    U.P. KulKarni

    2000-10-01

    Full Text Available Closed vessel technique is essentially used to determine the force constant, vivacity and the burning rate of gun propellants. In fact, it is the only method to find out these three parameters experimentally. It is a well-known fact that however small the propellant burning time may be, there will be heat loss to the walls of the vessel due to conduction, convection, radiation and also due to the expansion of the vessel. This fact necessitates applying correction to the observed maximum pressure in the experiment. An analysis is presented in this paper as to how this heat loss can be modelled along with discussion about other models reported in this field.

  12. Homogenization Issues in the Combustion of Heterogeneous Solid Propellants

    Science.gov (United States)

    Chen, M.; Buckmaster, J.; Jackson, T. L.; Massa, L.

    2002-01-01

    We examine random packs of discs or spheres, models for ammonium-perchlorate-in-binder propellants, and discuss their average properties. An analytical strategy is described for calculating the mean or effective heat conduction coefficient in terms of the heat conduction coefficients of the individual components, and the results are verified by comparison with those of direct numerical simulations (dns) for both 2-D (disc) and 3-D (sphere) packs across which a temperature difference is applied. Similarly, when the surface regression speed of each component is related to the surface temperature via a simple Arrhenius law, an analytical strategy is developed for calculating an effective Arrhenius law for the combination, and these results are verified using dns in which a uniform heat flux is applied to the pack surface, causing it to regress. These results are needed for homogenization strategies necessary for fully integrated 2-D or 3-D simulations of heterogeneous propellant combustion.

  13. Low head hydro power; low cost, low maintenance propeller turbines

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-10-15

    Market research identified a significant demand for propeller turbines capable of producing between 5kW and 25kW of electricity from heads of water of between 2 and 8m. This project produced a standardised propeller turbine design, which also met the additional requirements of low cost and low maintenance. The key features of the new design are considered to be:- the simplicity of design; its robustness; the use of standard shapes, sizes and off-the-shelf components; its maintainability; the precise blade shape, which is designed for high efficiency and operation without cavitation or 'rough' running, (requires accurate casting); the location of the machine above maximum tail-water level. The turbine design is suitable for the upper part of the low-head range. Further design work could be done to cover the lower part of the range in the form of a tube turbine configuration. (author)

  14. Motion corrected intracranial MRA using PROPELLER with RF quadratic encoding.

    Science.gov (United States)

    Zwart, Nicholas R; Pipe, James G

    2009-06-01

    A new motion corrected Time-of-Flight MRA technique named Variable Pitch PROPELLER is presented. This technique employs the PROPELLER acquisition and reconstruction scheme for in-plane bulk motion correction. A non- Fourier through-plane encoding mechanism called quadratic encoding boosts SNR, relative to conventional 2D MRA, in lieu of traditional 3D encoding. Partial Fourier encoding is applied in the slice direction for a further reduction in scan time. This work details the construction and optimization of this technique. VPPROP MRAs are compared with a clinical MOTSA protocol. Initial results show promising robustness to bulk motion effects. The comparisons with MOTSA provide insight as to the additions required to create a comparable scan. PMID:19353668

  15. Decontamination of MMH- and NTO/MON-propellant Tanks

    Science.gov (United States)

    Jokela, K.; Kaelsch, I.

    2004-10-01

    Decontamination of liquid propellant tanks, namely MMH and NTO/MON tanks, due to emergency off- loading of a spacecraft can cause damage to the propellant tank material if safety precautions are not taken into account. MMH (Mono-Methyl Hydrazine) reacts with water with an exothermic reaction that causes temperature rise and hydrous reaction product formation. NTO and MON (Nitrogen Tetroxide Oxidiser / Mixed Oxides of Nitrogen) react with water forming nitrous and nitric acid, which may cause corrosion and enhance Stress Corrosion Cracking (SCC) in the titanium tank material. To avoid these problems, a new procedure with a numerical prediction tool for decontamination of MMH tank has been developed, used and assessed to decontaminate the MMH tank of the ESA Rosetta spacecraft successfully. The ESA proposed procedure for MON oxidiser tank emergency off-loading and decontamination is also presented.

  16. Design and qualification of the Cluster satellite propellant tankage

    Science.gov (United States)

    Ballinger, Ian

    1993-06-01

    The Cluster propellant tank is an all titanium welded assembly used in identical form for both the monomethyl hydrazine fuel and nitrogen tetroxide oxidizer service. The tank is to be used on four flight Cluster spacecraft with six tanks per spacecraft. The theoretical design of the tank utilized a suite of computer aided design (CAD) tools for assessment of all environments. Initial design evaluation identified the primary design driven of tank fundamental frequency, static acceleration and sine vibration, commensurate with minimizing mass. The primary design driven are all a function of the tank's isostatic hardmounted boundary conditions. The Cluster propellant tank has undergone comprehensive Qualification test program. The test results have been used to validate the theoretical design.

  17. Effect of Propeller on Engine Cooling System Drag and Performance

    Science.gov (United States)

    Katz, Joseph; Corsiglia, Victor R.; Barlow, Philip R.

    1982-01-01

    The pressure recovery of incoming cooling air and the drag associated with engine cooling of a typical general aviation twin-engine aircraft was Investigated experimentally. The semispan model was mounted vertically in the 40 x 80-Foot Wind Tunnel at Ames Research Center. The propeller was driven by an electric motor to provide thrust with low vibration levels for the cold-now configuration. It was found that the propeller slip-stream reduces the frontal air spillage around the blunt nacelle shape. Consequently, this slip-stream effect promotes flow reattachment at the rear section of the engine nacelle and improves inlet pressure recovery. These effects are most pronounced at high angles of attack; that is, climb condition. For the cruise condition those improvements were more moderate.

  18. CONSTRUCTION SELF-PROPELLED PNEUMOPUNCHERS WITH LOCKING MECHANISM

    OpenAIRE

    V. K. Perederey

    2016-01-01

    The paper reveals one of possible methods for higher productivity and reliability of building self-propelled pneumopunchers which are intended for making holes in soil while using trenchless method and constructing various engineering communications under car, tram and rail lines, airport runways. A new design of building pneumopuncher with increased productivity due to higher speed for hole formation in soil and its reliability has been presented in the paper. A formula for determination of ...

  19. Non-equilibrium clustering of self-propelled rods

    OpenAIRE

    Peruani, Fernando; Deutsch, Andreas; Baer, Markus

    2006-01-01

    Motivated by aggregation phenomena in gliding bacteria, we study collective motion in a twodimensional model of active, self-propelled rods interacting through volume exclusion. In simulations with individual particles, we find that particle clustering is facilitated by a sufficiently large packing fraction (eta) or length-to-width ratio (kappa). The transition to clustering in simulations is well captured by a mean-field model for the cluster size distribution, which predicts that the transi...

  20. Dynamic loads on marine propellers due to intermittent ventilation

    OpenAIRE

    Califano, Andrea

    2010-01-01

    Dynamic Positioning (DP) systems are increasingly replacing traditional positionkeeping methods—such as jack-up barges and anchoring systems—on board ships operating in ever deeper waters. During these operations, the combined effect of heavy sea states and high propeller loadings have caused a number of damages on azimuth and tunnel thrusters, causing service downtime and requiring costly repairs. Damages in rough seas were reported also during transit operations. These damages can be caused...

  1. Dynamic regimes of hydrodynamically coupled self-propelling particles

    OpenAIRE

    Llopis, Isaac; Pagonabarraga, Ignacio

    2006-01-01

    We analyze the collective dynamics of self-propelling particles (spps) which move at small Reynolds numbers including the hydrodynamic coupling to the suspending solvent through numerical simulations. The velocity distribution functions show marked deviations from Gaussian behavior at short times, and the mean-square displacement at long times shows a transition from diffusive to ballistic motion for appropriate driving mechanism at low concentrations. We discuss the structures the spps form ...

  2. Robust method of trapping self-propelling particles

    Science.gov (United States)

    Lacubtan, Roger Joseph L.; Confesor, Mark Nolan P.

    2015-01-01

    The ability to collect self-propelling particles (SPP) is an essential requirement for possible use of SPP in technological applications. In this paper we proposed a novel way of trapping SPP's, through guided trapping of SPP's in V-shaped trap. We performed brownian dynamic simulation via a modified Escape and Predation model developed by L. Angelani (Phys. Rev. Lett., 2012) to assess the validity of the proposed trapping method.

  3. Dynamic regimes of hydrodynamically coupled self-propelling particles

    Science.gov (United States)

    Llopis, I.; Pagonabarraga, I.

    2006-09-01

    We analyze the collective dynamics of self-propelling particles (spps) which move at small Reynolds numbers including the hydrodynamic coupling to the suspending solvent through numerical simulations. The velocity distribution functions show marked deviations from Gaussian behavior at short times, and the mean-square displacement at long times shows a transition from diffusive to ballistic motion for appropriate driving mechanism at low concentrations. We discuss the structures the spps form at long times and how they correlate to their dynamic behavior.

  4. Fuel-Cell Power Source Based on Onboard Rocket Propellants

    Science.gov (United States)

    Ganapathi, Gani; Narayan, Sri

    2010-01-01

    The use of onboard rocket propellants (dense liquids at room temperature) in place of conventional cryogenic fuel-cell reactants (hydrogen and oxygen) eliminates the mass penalties associated with cryocooling and boil-off. The high energy content and density of the rocket propellants will also require no additional chemical processing. For a 30-day mission on the Moon that requires a continuous 100 watts of power, the reactant mass and volume would be reduced by 15 and 50 percent, respectively, even without accounting for boiloff losses. The savings increase further with increasing transit times. A high-temperature, solid oxide, electrolyte-based fuel-cell configuration, that can rapidly combine rocket propellants - both monopropellant system with hydrazine and bi-propellant systems such as monomethyl hydrazine/ unsymmetrical dimethyl hydrazine (MMH/UDMH) and nitrogen tetroxide (NTO) to produce electrical energy - overcomes the severe drawbacks of earlier attempts in 1963-1967 of using fuel reforming and aqueous media. The electrical energy available from such a fuel cell operating at 60-percent efficiency is estimated to be 1,500 Wh/kg of reactants. The proposed use of zirconia-based oxide electrolyte at 800-1,000 C will permit continuous operation, very high power densities, and substantially increased efficiency of conversion over any of the earlier attempts. The solid oxide fuel cell is also tolerant to a wide range of environmental temperatures. Such a system is built for easy refueling for exploration missions and for the ability to turn on after several years of transit. Specific examples of future missions are in-situ landers on Europa and Titan that will face extreme radiation and temperature environments, flyby missions to Saturn, and landed missions on the Moon with 14 day/night cycles.

  5. Internal ballistics simulation of a solid propellant rocket motor

    OpenAIRE

    Gomes, Marc Faria

    2013-01-01

    In the design and development of solid propellant rocket motors, the use of numerical tools able to simulate, predict and reconstruct the behaviour of a given motor in all its operative conditions is particularly important in order to decrease all the planning and costs. This study is devoted to present an approach to the numerical simulation of a given SPRM internal ballistics, NAWC no. 13, during the quasi steady state by means of a commercial numerical tool, ANSYS FLUENT....

  6. Self-propelled motion in a viscous compressible fluid

    Czech Academy of Sciences Publication Activity Database

    Mácha, Václav; Nečasová, Šárka

    2016-01-01

    Roč. 146, č. 2 (2016), s. 415-433. ISSN 0308-2105 R&D Projects: GA ČR(CZ) GAP201/11/1304; GA ČR GA13-00522S Institutional support: RVO:67985921 Keywords : self-propelled motion * compressible fluid * deformable structure Subject RIV: BA - General Mathematics Impact factor: 1.009, year: 2014 http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=10065194&fileId=S0308210515000487

  7. Plasma propellant interactions in an electrothermal-chemical gun

    OpenAIRE

    Taylor, M. J.

    2009-01-01

    This Thesis covers work conducted to understand the mechanisms underpinning the operation of the electrothermal-chemical gun. The initial formation of plasma from electrically exploding wires, through to the development of plasma venting from the capillary and interacting with a densely packed energetic propellant bed is included. The prime purpose of the work has been the development and validation of computer codes designed for the predictive modelling of the elect roth...

  8. Longitudinal Stability Criteria for a Propeller-Driven Aircraft

    OpenAIRE

    Gil Iosilevskii

    2010-01-01

    The Routh criterion is used to assess longitudinal dynamic stability of a propeller-driven aircraft. Under a few plausible assumptions on possible ranges of the pertinent stability derivatives, it reduces to a pair of simple conditions imposing a traditional aft limit (the forward of the maneuver and the neutral-speed-stability points) on the center-of-gravity position and an upper limit on the longitudinal moment of inertia. It is demonstrated that most aircraft have sufficiently small inert...

  9. Modeling of Unsteady Sheet Cavitation on Marine Propeller Blades

    OpenAIRE

    Spyros A. Kinnas; HanSeong Lee; Yin L. Young

    2003-01-01

    Unsteady sheet cavitation is very common on marine propulsor blades. The authors summarize a lifting-surface and a surface-panel model to solve for the unsteady cavitating flow around a propeller that is subject to nonaxisymmetric inflow. The time-dependent extent and thickness of the cavity were determined by using an iterative method. The cavity detachment was determined by applying the smooth detachment criterion in an iterative manner. A nonzeroradius developed vortex cavity model was uti...

  10. The effect of a foul release coating on propeller performance

    OpenAIRE

    Atlar, M; Glover, EJ; Candries, Maxim; Mutton, RJ; Anderson, CD

    2002-01-01

    With the imminent ban on the application of coatings of TBT self-polishing co-polymers in January 2003 and their eventual prohibition in 2008 a great deal of research is being conducted into the performance of the possible alternatives. As part of the ongoing work investigating the hydrodynamic performance of foul release systems, being carried out at the University of Newcastle upon Tyne, a study into the possible benefits of their use on propellers has been conducted. The ...

  11. Parametric study of propeller boss cap fins for container ships

    OpenAIRE

    Lim Sang-Seop; Kim Tae-Won; Lee Dong-Myung; Kang Chung-Gil; Kim Soo-Young

    2014-01-01

    The global price of oil, which is both finite and limited in quantity, has been rising steadily because of the increasing requirements for energy in both developing and developed countries. Furthermore, regulations have been strengthened across all industries to address global warming. Many studies of hull resistance, propulsion and operation of ships have been performed to reduce fuel consumption and emissions. This study examined the design parameters of the propeller boss cap fin (PBCF) an...

  12. Numerical Prediction of Hydromechanical Behaviour of Controllable Pitch Propeller

    OpenAIRE

    Saman Tarbiat; Hassan Ghassemi; Manouchehr Fadavie

    2014-01-01

    The research described in this paper was carried out to predict hydrodynamic and frictional forces of controllable pitch propeller (CPP) that bring about fretting problems in a blade bearing. The governing equations are Reynolds-averaged Navier-Stokes (RANS) and are solved by OpenFOAM solver for hydrodynamic forces behind the ship’s wake. Frictional forces are calculated by practical mechanical formulae. Different advance velocities with constant rotational speed for blades are used to achiev...

  13. An Efficient Procedure for Viscous Propeller Flow Field Calculations

    OpenAIRE

    Boyle, Fergal

    2002-01-01

    An efficient procedure has been developed for the computation of the three-dimensional, compressible, viscous flow field around a general propeller geometry with the inflow at zero angles of incidence and yaw. The solution procedure combines a recently developed Reynolds-Averaged-Navier-Stokes equations solver with a commercially available grid generator designed specifically for turbomachinery configurations. Preliminary results from the calculation of laminar and turbulent incompressible fl...

  14. How to Build a Complex, Functional Propeller Protein, From Parts.

    Science.gov (United States)

    Clark, Patricia L

    2016-04-01

    By combining ancestral sequence reconstruction and in vitro evolution, Smock et al. identified single motifs that assemble into a functional five-bladed β-propeller, and a likely route for conversion into the more complex, extant single chain fusion. Interestingly, although sequence diversification destabilized five-motif fusions, it also destabilized aggregation-prone intermediates, increasing the level of functional protein in vivo. PMID:26971075

  15. CFD and FEM Model of an Underwater Vehicle Propeller

    OpenAIRE

    Chruściel Tadeusz; Ciba Ewelina; Dopke Julita

    2014-01-01

    Within the framework of the project for design and optimization of the Remotely Operated Vehicle (ROV), research on its propulsion has been carried out. Te entire project was supported by CFD and FEM calculations taking into account the characteristics of the underwater vehicle. One of the tasks was to optimize the semi-open duct for horizontal propellers, which provided propulsion and controllability in horizontal plane. In order to create a measurable model of this task it was necessary to ...

  16. Trapping of interacting propelled colloidal particles in inhomogeneous media

    OpenAIRE

    Magiera, Martin P.; Brendel, Lothar

    2014-01-01

    A trapping mechanism for propelled colloidal particles based on an inhomogeneous drive is presented and studied by means of computer simulations. In experiments this method can be realized using photophoretic Janus particles driven by a light source, which shines through a shading mask and leads to an accumulation of the particles in the passive part. An equation for an accumulation parameter is derived using the effective inhomogeneous diffusion constant generated by the inhomogeneous drive....

  17. Experimental study on processability of ammonium perchlorate/hydroxyl-terminated polybutadiene composite propellant (I). Influences of operating temperature on viscosity of uncured propellant

    Energy Technology Data Exchange (ETDEWEB)

    Koga, M.; Hagihara, Y. [National Defense Academy, Kanagawa (Japan)

    1998-01-01

    Ammonium perchlorate (AP)/hydroxyl-terminated polybutadiene (HTPB) composite propellant was adopted in this study, because AP/HTPB composite propellant is the most widely used one at present. In order to design the formulation of AP/HTPB composite propellant, it is necessary to spread the range of a specific impulse of AP/HTPB composite propellant widely, especially towards a high specific impulse region. Specific impulse of AP/HTPB composite propellant increases with an increasing AP content and when the AP content is about 90wt% the maximum specific impulse can be realized theoretically. Because an upper limit of AP content in propellant exists technically for the size distribution of AP used, the upper limit of specific impulse must be so. In order to increase the upper limit of specific impulse, it is necessary to increase the upper limit of AP content. In this study, the relationships between the viscosity of HTPB with a curing agent or uncured propellant and the curing time were investigated at temperatures from 313K to 353K, and was made to find out the optimum operating temperature for mixing and casting of uncured propellant experimentally. 4 refs., 5 figs.

  18. 14 CFR Appendix F to Part 36 - Flyover Noise Requirements for Propeller-Driven Small Airplane and Propeller-Driven, Commuter...

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flyover Noise Requirements for Propeller-Driven Small Airplane and Propeller-Driven, Commuter Category Airplane Certification Tests Prior to December 22, 1988 F Appendix F to Part 36 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT NOISE...

  19. Experimental study of high-speed counter-rotation propeller on low speed wind range; Dojiku hantengata kosoku propeller no teisokuiki ni okeru fudo jikken

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Collaborative research was conducted by National Aerospace Laboratory and Japan Aircraft Development Company in the period of fiscal 1988-1992 into methods for testing aircraft with advanced propeller in low-speed wind tunnel. The propulsion efficiency of the currently available high-bypass turbofan engine is approximately 60% in the vicinity of Mach number 0.85. Propeller-driven aircraft, whose propulsion efficiency is as high as 80% in the low Mach number domain, are scarcely in practical use in the domain of Mach number 0.75 or higher. There are studies reported abroad as well as in Japan for the propeller-driven aircraft to enjoy higher propeller propulsion efficiency even in the vicinity of Mach number 0.8 by modifying the propeller diameter, number of blades, and blade sections, etc. This paper describes the experimental research into the high-speed counter-rotation propeller. A counter-rotation propeller 0.3m in diameter and provided with coaxially arranged 8times2 SR-2 blades is evaluated for pitch angles during the takeoff and landing modes, for thrust characteristics at the pitch angle for the cruising mode, and for propeller backwash and noise. 15 refs., 72 figs., 9 tabs.

  20. Transition Metal Carbohydrazide Nitrates: Burn-rate Modifiers for Propellants

    Directory of Open Access Journals (Sweden)

    S. H. Sonawane

    2006-07-01

    Full Text Available This paper discusses the synthesis and characterisation of cobalt (Co, nickel (Ni andcopper (Cu carbohydrazide nitrates. In differential scanning calorimetry (DSC, the complexesexhibited exothermic decomposition indicating their energetic nature. The commencement ofdecomposition was observed at 220 °C for Ni complex, and at 160 °C for Co complex whereasthat of Cu complex occurred at 75 °C. In view of the better thermal stability, Ni and Co complexeswere selected for further study. The activation energy of decomposition of Ni and Co complexeswere found to be 47 kcal/mol and 60 kcal/mol respectively. Impact and friction sensitivity testresults revealed relatively lower vulnerability of carbohydrazide cobalt nitrate. Its incorporationin an ammonium perchlorate (AP-based composite propellant led to 9-19 per cent enhancementwhereas that of carbohydrazide nickel nitrate resulted in 28-74 per cent enhancement in burningrates in the pressure range 1.9 MPa to 8.8 MPa. Exothermic decomposition of the coordinationcomplexes on propellant surface and involvement of metal at molecular level formed ondecomposition of the complexes in combustion environment of composite propellant may beattributed to the catalytic effect of this class of compounds on the lines of reported literature.

  1. Formulation and properties of ADN/GAP propellants

    Energy Technology Data Exchange (ETDEWEB)

    Menke, Klaus; Heintz, Thomas; Schweikert, Wenka; Keicher, Thomas; Krause, Horst [Fraunhofer-Institut fuer Chemische Technologie ICT, Pfinztal (Germany)

    2009-06-15

    In this contribution two ways are described, how it is possible to achieve perfectly cured and processible propellants with prilled ADN, low amounts of HMX 5{mu}m mps and a binder system based on GAP diole and GAP triole oligomers with and without TMETN as a nitrate ester plasticizer. It was shown how it will be possible to suppress the strongly gas forming reaction between ADN and reactive isocyanates by a mixture of stabilizers. In this way it was possible to create minimum smoke ADN/HMX/GAP/TMETN propellants cured with the triisocyanate N100. In the second part an unconventional binder system based on the 1.3 dipolar cycloaddition reaction of azido groups with acetylene compounds forming 1,2,3-triazole heterocyclic rings has been applied for ADN/GAP and AP/GAP propellants. Together with small parts of HMX formulations with ADN/HMX/GAP and the corresponding AP/HMX/GAP exhibit high thermodynamic performance, are easily processible, and cure successfully at 60 C. Their basic properties consisting of burning behavior and mechanical properties, at ambient temperature, chemical stability, and sensitivity have been investigated and are compared to each other. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  2. Propellant Savings during Soyuz Undock from the International Space Station

    Science.gov (United States)

    Turett, Fiona

    2016-01-01

    As a vehicle continuously orbiting Earth for over a decade, the International Space Station (ISS) must be conscious of ways to conserve consumables to maximize the efficiency of cargo flights to ISS. One such consumable is propellant. As part of an ongoing effort to minimize propellant usage onboard ISS and use control moment gyroscopes as much as possible for ISS control, an effort was made in late 2014 to allow Soyuz manned vehicle undockings without requiring the use of thrusters. This method, which has been used for four Soyuz undockings, saves up to 160 kg of propellant each year. Fiona completed a B.S. is Mechanical Engienering at Washington University in St. Louis in 2009, after which she moved to Houston, TX to begin working at NASA Johnson Space Center. She currently works in the Flight Operations Directorate as an ADCO (Attitude Determination and Control Officer) flight controller and MCG (Motion Control Group) instructor. Her responsibilities include operating the motion control systems of the ISS in Mission Control, interfacing with Russian colleagues, mentoring and teaching flight controller trainees, and training astronauts for their missions to ISS.

  3. Large-eddy simulations of a propelled submarine model

    Science.gov (United States)

    Posa, Antonio; Balaras, Elias

    2015-11-01

    The influence of the propeller on the wake as well as the evolution of the turbulent boundary layers over an appended notional submarine geometry (DARPA SUBOFF) is reported. The present approach utilizes a wall-resolved LES, coupled with an immersed boundary formulation, to simulate the flow model scale Reynolds numbers (Re = 1 . 2 e + 06 , based on the free-stream velocity and the length of the body). Cylindrical coordinates are adopted, and the computational grid is composed of 3.5 billion nodes. Our approach has been validated on the appended submarine body in towed conditions (without propeller), by comparisons to wind tunnel experiments in the literature. The comparison with the towed configuration shows profound modifications in the boundary layer over the stern surface, due to flow acceleration, with higher values of turbulent kinetic energy in the inner layer and lower values in the outer layer. This behavior was found tied to a different topology of the coherent structures between propelled and towed cases. The wake is also highly affected, and the momentum deficit displays a non-monotonic evolution downstream. An axial peak of turbulent kinetic energy replaces the bimodal distribution of the stresses in the wake, observed in the towed configuration. Supported by ONR Grant N000141110455, monitored by Dr. Ki-Han Kim.

  4. Swarm behavior of self-propelled rods and swimming flagella

    Science.gov (United States)

    Yang, Yingzi; Marceau, Vincent; Gompper, Gerhard

    2010-09-01

    Systems of self-propelled particles are known for their tendency to aggregate and to display swarm behavior. We investigate two model systems: self-propelled rods interacting via volume exclusion and sinusoidally beating flagella embedded in a fluid with hydrodynamic interactions. In the flagella system, beating frequencies are Gaussian distributed with a nonzero average. These systems are studied by Brownian-dynamics simulations and by mesoscale hydrodynamics simulations, respectively. The clustering behavior is analyzed as the particle density and the environmental or internal noise are varied. By distinguishing three types of cluster-size probability density functions, we obtain a phase diagram of different swarm behaviors. The properties of clusters such as their configuration, lifetime, and average size are analyzed. We find that the swarm behavior of the two systems, characterized by several effective power laws, is very similar. However, a more careful analysis reveals several differences. Clusters of self-propelled rods form due to partially blocked forward motion and are therefore typically wedge shaped. At higher rod density and low noise, a giant mobile cluster appears, in which most rods are mostly oriented toward the center. In contrast, flagella become hydrodynamically synchronized and attract each other; their clusters are therefore more elongated. Furthermore, the lifetime of flagella clusters decays more quickly with cluster size than of rod clusters.

  5. Interpenetrating Polymer Networks as Binders for Solid Composite Propellants

    Directory of Open Access Journals (Sweden)

    S. Parthiban

    1992-07-01

    Full Text Available A new family of polymeric binders for solid composite propellants is proposed, based on two component interpenetrating polymer networks (IPNs. These networks comprise two different polyurethanes based on hydroxy terminated polybutadiene and ISRO polyol interpenetrated with two different vinyl polymers, viz poly methyl methacrylate and polystyrene. the networks synthesized by the simultaneous interpenetrating technique have been characterized for their properties, such as stress-strain, density, viscosity, thermal degradation, and heat of combustion. Phase morphologies have been determined using electron microscopy. Suitable explanations have been adduced to rationalize the properties of IPNs in terms of their structures and chain interactions. A study of the mechanical properties and burning rates of the ammonium perchlorate (AP-based solid propellant using the newly synthesised IPNs as binders, has been carried out. The results show that both mechanical strength and burning rate of solid propellants could be suitably modified by simply changing the nature and/or the ratio of the two interpenetrating polymer components.

  6. Ammonium nitrate as an oxidizer in solid composite propellants

    Science.gov (United States)

    Manelis, G. B.; Lempert, D. B.

    2009-09-01

    Despite the fact that ammonium nitrate (AN) has the highest hydrogen content and fairly high oxygen balance (compared to other oxidizers), its extremely low formation enthalpy and relatively low density makes it one of the worst power oxidizers in solid composite propellants (SCP). Nevertheless, AN has certain advantages - the combustion of the compositions containing AN is virtually safe, its combustion products are ecologically clean, it is very accessible and cheap, and also very thermostable (far more stable than ammonium dinitramide (ADN)). Besides, its low density stops being a disadvantage if the propellant has to be used in deep space and therefore, must be carried there with other rocket carriers. The low cost of AN may also become a serious advantage in the AN application even in lower stages of multistage space launchers as well as in one-stage space launchers with low mass fraction of the propellant. The main specific features relevant to the creation of AN-based SCPs with the optimal energetic characteristics are discussed. The use of metals and their hydrides and proper fuel-binders as well as the recent successes in phase stabilization of AN are described.

  7. Self-propelled droplet behavior during condensation on superhydrophobic surfaces

    Science.gov (United States)

    Chu, Fuqiang; Wu, Xiaomin; Zhu, Bei; Zhang, Xuan

    2016-05-01

    Self-propelled droplet motion has applications in various engineering fields such as self-cleaning surfaces, heat transfer enhancement, and anti-icing methods. A superhydrophobic surface was fabricated using two simultaneous chemical reactions with droplet condensation experiments performed on the horizontal superhydrophobic surface to characterize the droplet behavior. The droplet behavior is classified into three types based on their motion features and leftover marks as immobile droplet coalescence, self-propelled droplet jumping, and self-propelled droplet sweeping. This study focuses on the droplet sweeping that occurs due to the ultra-small rolling angle of the superhydrophobic surface, where the resulting droplet sweeps along the surface, merging with all the droplets it meets and leaving a long, narrow, clear track with a large droplet at the end of the track. An easy method is developed to predict the droplet sweeping direction based on the relative positions of the droplets just before coalescence. The droplet sweeping always absorbs dozens of droplets and is not limited by the surface structures; thus, this sweeping has many useful applications. In addition, the relationships between the droplet behavior and the number of participating droplets are also analyzed statistically.

  8. NUMERICAL PREDICTION OF BLADE FREQUENCY NOISE OF CAVITATING PROPELLER

    Institute of Scientific and Technical Information of China (English)

    YE Jin-ming; XIONG Ying; LI Fang; WANG Zhan-zhi

    2012-01-01

    The blade frequency noise of a cavitating propeller in a uniform flow is analyzed in the time domain.The unsteady loading (of a dipole source) and the sheet cavity volume (of a monopole source) on the propeller surface are calculated by a potential-based surface panel method.Then the time-dependent pressure and the cavity volume data are used as the input for the Fowcs Williams-Hawkings formulation to predict the acoustics pressure.The integration of the noise source is performed over the true blade surface rather than the ideal blade surface without thickness.The noise characteristics of the cavitating propeller are discussed.With the sheet cavitation,the thickness (cavitation) noise is larger than the loading noise and is the dominant noise source.The noise directivity is not as clear as that of the noise under a non-cavitation condition.The cavitation noise is attenuated more slowly than the non-cavitation noise.

  9. Experimental Investigation of the Decay from A Ship's Propeller

    Institute of Scientific and Technical Information of China (English)

    W. Lam; G. A. Hamill; SONG Yong-chen; D. J. Robinson; S. Raghunathan

    2011-01-01

    In the present study, an experimental investigation of the decay of the maximum velocity and its turbulent characteristics behind a ship propeller, in "bollard pull" condition (zero speed of advance), is reported. Velocity measurements were performed in laboratory by use of a Laser Doppler Anemometry (LDA) measurement system. Earlier researchers described that the maximum axial velocity is constant at the initial stage of a ship's propeller jet (Fuehrer and Romisch, 1977; Blaauw and van de Kaa, 1978; Berger et al., 1981; Verhey, 1983) as reported in a pure water jet (Albert.son et al., 1950; Lee et al., 2002; Dai, 2005), but a number of researchers disagreed with the constant velocity assumption. The present study found that the maximum axial velocity decays in the zone of flow establishment and the zone of established flow with different rates. The investigation provides an insight into the decays of both the maximum velocity and the maximum turbulent fluctuation in axial, tangential and radial components and the decay of the maximum turbulent kinetic energy. Empirical equations are proposed to allow coastal engineers to estimate the jet characteristics from a ship's propeller.

  10. Chiral Colloidal Molecules And Observation of The Propeller Effect

    Science.gov (United States)

    2013-01-01

    Chiral molecules play an important role in biological and chemical processes, but physical effects due to their symmetry-breaking are generally weak. Several physical chiral separation schemes which could potentially be useful, including the propeller effect, have therefore not yet been demonstrated at the molecular scale. However, it has been proposed that complex nonspherical colloidal particles could act as “colloidal molecules” in mesoscopic model systems to permit the visualization of molecular phenomena that are otherwise difficult to observe. Unfortunately, it is difficult to synthesize such colloids because surface minimization generally favors the growth of symmetric particles. Here we demonstrate the production of large numbers of complex colloids with glancing angle physical vapor deposition. We use chiral colloids to demonstrate the Baranova and Zel’dovich (BaranovaN. B.Zel’dovichB. Y.Chem. Phys. Lett.1978, 57, 435) propeller effect: the separation of a racemic mixture by application of a rotating field that couples to the dipole moment of the enantiomers and screw propels them in opposite directions. The handedness of the colloidal suspensions is monitored with circular differential light scattering. An exact solution for the colloid’s propulsion is derived, and comparisons between the colloidal system and the corresponding effect at the molecular scale are made. PMID:23883328

  11. Perforator propeller flaps for sacral and ischial soft tissue reconstruction

    Directory of Open Access Journals (Sweden)

    Korambayil Pradeoth

    2010-01-01

    Full Text Available The perforator-based flaps in the sacral and ischial region is designed according to the localization of perforators that penetrate the gluteus maximus muscle, reach the intra-fascial and supra-fascial planes with the overlying skin forming a rich vascular plexus. The perforator-based flaps described in this article are highly vascularized, have minimal donor site morbidity, and do not require the sacrifice of the gluteus maximus muscle. In a period between April 2008 and March 2009, six patients with sacral pressure sore were reconstructed with propeller flap method based on superior gluteal and parasacral artery perforators. One flap loss was noted. Three cases of ischial pressure sore were reconstructed with longitudinal propeller flap cover, based on inferior gluteal artery perforator. One flap suffered wound infection and dehiscence. Two cases of pilonidal sinus were reconstructed with propeller flap based on parasacral perforators. Both the flaps survived without any complications. Donor sites were closed primarily. In the light of this, they can be considered among the first surgical choices to re-surface soft tissue defects of the sacral and ischial regions. In the series of 11 patients, two patients (18% suffered complications.

  12. Perforator propeller flaps for sacral and ischial soft tissue reconstruction

    Science.gov (United States)

    Korambayil, Pradeoth M.; Allalasundaram, KV; Balakrishnan, TM

    2010-01-01

    The perforator-based flaps in the sacral and ischial region is designed according to the localization of perforators that penetrate the gluteus maximus muscle, reach the intra-fascial and supra-fascial planes with the overlying skin forming a rich vascular plexus. The perforator-based flaps described in this article are highly vascularized, have minimal donor site morbidity, and do not require the sacrifice of the gluteus maximus muscle. In a period between April 2008 and March 2009, six patients with sacral pressure sore were reconstructed with propeller flap method based on superior gluteal and parasacral artery perforators. One flap loss was noted. Three cases of ischial pressure sore were reconstructed with longitudinal propeller flap cover, based on inferior gluteal artery perforator. One flap suffered wound infection and dehiscence. Two cases of pilonidal sinus were reconstructed with propeller flap based on parasacral perforators. Both the flaps survived without any complications. Donor sites were closed primarily. In the light of this, they can be considered among the first surgical choices to re-surface soft tissue defects of the sacral and ischial regions. In the series of 11 patients, two patients (18%) suffered complications. PMID:21217972

  13. Compatability of dispersion-strengthened platinum with resistojet propellants

    Science.gov (United States)

    Whalen, Margaret V.; Nathal, Michael V.

    1987-01-01

    Resistojets for the Space Station require long life and multipropellant capability. The choice of available materials to meet these requirements is limited. Dispersion-strengthened platinum was selected. Past results indicated that it should be suffieiently inert in candidate propellant environments and should be capable of operating at moderate temperatures for extended periods. A series of propellant compatibility tests was done with platinum strengthened with either yttria or zirconia. Data presented included the results of 1000-hr tests in CO2, H2, ammonia (NH3), N2, steam, hydrazine (N2H4), and methane (CH4); and 2000-hr tests in H2 and NH3. The platinum samples were tested at 1400 C in CO2, H2, NH3, N2, steam, and N2H4; at 500 C in CH4; and at 800 C in N2H4. The mass-loss results indicated material life, exptrapolated from experimental mass-loss data, in excess of 100 000 hr in all environments except steam and N2H4, where it was greater than or =45000 hr. Generally, on the basis of mass loss, there were no compatibility concerns in any of the environments considered. Optical and scanning electron microscopy were used to determine the effect of propellants on the material surface and to evaluate material stability.

  14. Compatibility experiments of facilities, materials, and propellants for electrothermal thrusters

    Science.gov (United States)

    Whalen, M. V.; Grisnik, S. P.; Sovey, J. S.

    1985-01-01

    Experiments were performed to determine the compatibility of materials and propellants for electro-thermal thrusters. Candidate propellants for resistojet propulsion include carbon dioxide, methane, hydrogen, ammonia, and hydrazine. The materials being examined are grain stabilized platinum for resistojets for space station and rhenium for high performance resistojets for satellites. Heater mass loss and deterioration of materials were evaluated. A coiled tube of platinum, with yttria dispersed throughout the base material to inhibit grain growth, was tested in carbon dioxide at 1300 C for 2000 hr. Post-test examination indicated the platinum-yttria heater would last over 100,000 hr with less than 10 percent mass loss. Short-term compatibility tests were conducted to test the integrity of the platinum-yttria in hydrogen, methane, carbon dioxide/methane mixtures and ammonia environments. In each of these 100 hr tests, the platinum-yttria mass change indicated a minimum coil life of 100,000 hr. Facility related effects were investigated in materials tests using rhenium heated to high temperatures. Vacuum facility water reduction was monitored using a mass spectrometer. In vacuum environments obtained using only diffusion pumping and those obtained with the assistance of cryogenic equipment there were mass gains in the rhenium heaters. These mass gains were the result of the high amount of oxygen and water contained in the gas. Propellant purity and preferred test facility environments are discussed.

  15. Deconsolidation and combustion performance of thermally consolidated propellants deterred by multi-layers coating

    Institute of Scientific and Technical Information of China (English)

    Zheng-gang XIAO; San-jiu YING; Fu-ming XU

    2014-01-01

    Both heating and solvent-spray methods are used to consolidate the standard grains of double-base oblate sphere propellants plasticized with triethyleneglycol dinitrate (TEGDN) (TEGDN propellants) to high density propellants. The obtained consolidated propellants are deterred and coated with the slow burning multi-layer coating. The maximum compaction density of deterred and coated consolidated propellants can reach up to 1.39 g/cm3. Their mechanic, deconsolidation and combustion performances are tested by the materials test machine, interrupted burning set-up and closed vessel, respectively. The static compression strength of consolidated propellants deterred by multi-layer coating increases significantly to 18 MPa, indicating that they can be applied in most circumstances of charge service. And the samples are easy to deconsolidate in the interrupted burning test. Furthermore, the closed bomb burning curves of the samples indicate a two-stage combustion phenomenon under the condition of certain thickness of coated multi-layers. After the outer deterred multi-layer coating of consolidated samples is finished burning, the inner consolidated propellants continue to burn and breakup into aggregates and grains. The high burning progressivity can be carefully obtained by the smart control of deconsolidation process and duration of consolidated propellants. The preliminary results of consolidated propellants show that a rapid deconsolidation process at higher deconsolidation pressure is presented in the dynamic vivacity curves of closed bomb test. Higher density and higher macro progressivity of consolidated propellants can be obtained by the techniques in this paper.

  16. On the Effects of an Installed Propeller Slipstream on Wing Aerodynamic Characteristics

    Directory of Open Access Journals (Sweden)

    F. M. Catalano

    2004-01-01

    Full Text Available This work presents an experimental study of the effect of an installed propeller slipstream on a wing boundary layer. The main objective was to analyse through wind tunnel experiments the effect of the propeller slipstream on the wing boundary layer characteristics such as: laminar flow extension and transition, laminar separation bubbles and reattachment and turbulent separation. Two propeller/wing configurations were studied: pusher and tractor. Experimental work was performed using two different models: a two-dimensional wing with a central cylindrical nacelle for the tractor configuration, and a simple two-dimensional wing with a downstream propeller for the pusher tests. The relative position between propeller and wing could be changed in the pusher model, and a total of 7 positions were analysed. For the tractor tests the relative propeller/wing was fixed, but three different propellers: two, three and four bladed were tested. Measurements included pressure distribution, hot wire anemometry and boundary layer characteristics by flow visualisation. The results showed that the pusher propeller inflow affects the wing characteristics by changing the lift, drag, and also delays the boundary layer transition and separation. These effects are highly dependent on the relative position of the wing/propeller. On the other hand, the tractor propeller slipstream induces transition and its effect is dependent on the number of blades.

  17. Improved method to label beta-2 agonists in metered-dose inhalers with technetium-99m

    Energy Technology Data Exchange (ETDEWEB)

    Ballinger, J.R.; Calcutt, L.E.; Hodder, R.V.; Proulx, A.; Gulenchyn, K.Y. (Ottawa Civic Hospital, Ottawa (Canada). Div. of Nuclear Medicine and Respiratory Unit)

    1993-01-01

    Labelling beta-2 agonists in a metered-dose inhaler (MDI) with technetium-99m allows imaging of the deposition of the aerosol in the respiratory tract. We have developed an improved labeling method in which anhydrous pertechnetate is dissolved in a small volume of ethanol, diluted with a fluorocarbon, and introduced into a commercial MDI. Imaging the MDI demonstrated that the [sup 99m]Tc was associated with the active ingredient, not just the propellant. The method has been used successfully with salbutamol and fenoterol MDIs and should be directly applicable to other MDIs which contain hydrophilic drugs. (Author).

  18. Xeroradiography in. beta. -thalassaemia

    Energy Technology Data Exchange (ETDEWEB)

    Scutellari, P.N.; Orzincolo, C.; Tamarozzi, R.

    1985-01-01

    Xeroradiographic investigations of the skull, hand, and elbow were performed on 27 patients with homozygous ..beta..-thalassaemia. The results were compared with plain radiographic examinations. Xeroradiography, because of its technical properties (i.e. edge contrast enhancement and wide latitude), was shown to demonstrate cortical thinning of long bones, swelling of the diploic space in the skull, and reticulated patterns in the elbow better than standard radiography. Moreover, the use of 'positive' mode imaging was shown to have advantages in the study of the skull and extremities.

  19. Realized Beta GARCH

    DEFF Research Database (Denmark)

    Hansen, Peter Reinhard; Lunde, Asger; Voev, Valeri Radkov

    2014-01-01

    particularly useful for modeling financial returns during periods of rapid changes in the underlying covariance structure. When applied to market returns in conjunction with returns on an individual asset, the model yields a dynamic model specification of the conditional regression coefficient that is known as...... conditional beta series during the financial crises.......We introduce a multivariate generalized autoregressive conditional heteroskedasticity (GARCH) model that incorporates realized measures of variances and covariances. Realized measures extract information about the current levels of volatilities and correlations from high-frequency data, which is...

  20. Double beta decay: present status

    OpenAIRE

    Barabash, A. S.

    2008-01-01

    The present status of double beta decay experiments (including the search for $2\\beta^{+}$, EC$\\beta^{+}$ and ECEC processes) are reviewed. The results of the most sensitive experiments are discussed. Average and recommended half-life values for two-neutrino double beta decay are presented. Conservative upper limits on effective Majorana neutrino mass and the coupling constant of the Majoron to the neutrino are established as $ < 0.75$ eV and $ < 1.9 \\cdot 10^{-4}$, respectively. Proposals fo...