123 research outputs found
Analisis Unjuk Kerja Pompa Sentrifugal dengan Variasi Head
Pompa Sentrifugal merupakan salah satu jenis pompa yang mempunyai lingkup penggunaan yang sangat luas terkait dengan head dan kapasitas yang dihasilkan. Pada kesempatan ini penulis mencoba memaparkan hasil penelitian tentang unjuk kerja pompa sentrifugal bila dilakukan variasi sudut bukaan katup (valve) pada pompa sentrifugal akan menghasilkan head. Sudut bukaan katup (valve) dimaksudkan untuk mengetahui peningkatan performance pompa yang terjadi akibat pembukaan sudut katup (valve). Menambah bukaan katup (valve) pompa sangat berpengaruh terhadap kapasitas aliran air yang dihasilkan, hal ini juga akan mempengaruhi kerja pompa, kecepatan spesifik, daya dan efesiensi pompa. Sehingga dapat diperoleh titik kerja pompa sentrifugal dengan Kapasitas (Q) 0,000733 m3/s, Head (H) 7,02 m, Daya Hidraulis (Ph) 50,501 watt, Effesiensi (Éłp) 16,396%, hal ini dapat terlaksana bila diikuti penambahan daya dari motor penggeraknya.Centrifugal pump is one type of pump that has a very wide scope of use related to the head and the capacity produced. On this occasion the author tries to explain the results of research on the performance of a centrifugal pump if variations in valve opening angle (valve) on a centrifugal pump will produce a head. The valve opening angle is intended to determine the increase in pump performance due to the opening of the valve angle. Adding to the valve opening (pump) is very influential on the flow capacity of the water produced, this will also affect the work of the pump, specific speed, power and pump efficiency. So that the centrifugal pump working point can be obtained with Capacity (Q) 0,000733 m3 / s, Head (H) 7,02 m, Hydraulics (Ph) 50,501 watts, Efficiency ((p) 16,396%, this can implemented if followed by the addition of power from the driving motor
4D Continuous Descent Operations Supported by an Electronic Flight Bag
This paper describes a set of flight simulation
experiments carried out with the DLRâs Generic Cockpit
Simulator (GECO). A new concept named time and energy
managed operations (TEMO), which aims to enable advanced
four dimensional (4D) continuous descent operations (CDO), was
evaluated after three full days of experiments with qualified
pilots. The experiment focused to investigate the possibility of
using a 4D-controller on a modern aircraft with unmodified or
only slightly modified avionic systems. This was achieved by
executing the controller in an Electronic Flight Bag (EFB) and
using the pilot to âclose the loopâ by entering speed and other
advisories into the autopilot Flight Control Unit (FCU). The
outcome of the experiments include subjective (questionnaires
answered by pilots) and objective (trajectory logs) data. Data
analysis showed a very good acceptance (both in terms of safety
and operability of the procedure) from the participating crews,
only with minor suggestions to be improved in future versions of
the controller and the speed advisories update rates. Good time
accuracy all along the descent trajectory was also observed.Peer ReviewedPostprint (published version
Defense in Desolation
This paper discusses different forms of defense strategies in architecture throughout history as well as how a buildingâs function morphs over time in relation to the political and social climate that surrounds it. Both of these concepts provide a framework for understanding my thesis drawing, âDefense in Desolation,â which uses bunkers in abandonment as a reference to the psychological impact of architecture outside of functionality
Flight Test Preparation of a 4D-controller for time constrained Continous Descent Operations (CDO)
Within the Clean Sky European project, a flight test prepared by the German Aerospace Center (DLR) is foreseen and meant to prove the capability of flying a Continous Descent Operation (CDO) while satisfying a time constraint at a waypoint. In light of this event, the main objective of this project is the preparation and possible improvement of a 4D-Controller that enables this time constrained CDO. The main task of the 4D-Controller that must be evaluated is the transmission of advisories by the controller to a human-machine interface on board the aircraft. These advisories are the ones that the pilot will further on introduce into the main flight guidance systems of the aircraft in order to perform the time constrained CDO.\vspace{2mm} The methodology used to evaluate the functionality of the controller has been the use of different simulation environments through witch data regarding the controller's behavior has been collected. The distinctive elements between the different simulation environments are the aircraft performance model used, the accuracy in simulating the meteorological conditions, as well as the graphic interface. Besides the controller's behavior, observations have been made regarding the human- machine interference and the robustness of the system. In all cases, the simulations have been performed in real-time and in manual mode, using a similar method as the one the pilot will use during the flight test. \vspace{2mm} The results and observations achieved from the simulations indicate a correct behavior of the controller. The time accuracy at the control waypoint is small enough to fulfill the operational requirements from a controller point of view. The use of thrust and speedbrakes has been acceptable within the scenarios that included disturbances and null in the ones without any disturbance having observed certain differences depending on the simulation environment used. The advisories were sent by the 4D-at an acceptable rate without adding a high additional amount of workload to the pilot. These and other results are shown throughout this project.Dins del marc del programa europeu Clean Sky,un test de vol preparat per la DLR (Centre
Aeroespacial Alemany) est
`
a previst. Davant la previsi
Ì
o dâaquest test de vol, la preparaci
Ì
o
i possible millora del comportament dâun controlador amb capacitats 4D utilitzat durant
una aproximaci
Ì
o de descens continu ha estat el principal objectiu dâaquest projecte. La
principal tasca a evaluar del controlador 4D
Ì
es lâenviament dâindicacions al pilot a trav
Ì
es
dâuna interf
Ì
ıcie home-m
`
aquina disponible a bord de lâavi
Ì
o. Aquestes indicacions s
Ì
on les
que el pilot posteriorment introduir
`
a en els principals sistemes de guiatge de lâavi
Ì
o per tal
de possibilitar el vol dâuna aproximaci
Ì
o de descens continu amb restriccions de temps al
sobrevolar determinats punts de navegaci
Ì
o de manera acurada.
La metodologia utilitzada per avaluar la funcionalitat del controlador ha estat lâutilitzaci
Ì
o de
diversos entorns de simulaci
Ì
o a trav
Ì
es dels quals la recopilaci
Ì
o de dades i les posteriors
observacions sâhan dut a terme. Els entorns de simulaci
Ì
o es diferencien per la manera
de modelar el comportament de lâavi
Ì
o, per les capacitats de simular condicions meteo-
rol
`
ogiques, aix
Ì
ı com tamb
Ì
e per la seva interf
Ì
ıcie gr
`
afica. A m
Ì
es de la resposta del con-
trolador, sâhan realitzat observacions relacionades amb la interacci
Ì
o home-m
`
aquina i la
robustesa del sistema. En tots els casos, les simulacions han estat en temps real i
ma-
nuals
, utilitzant un m
`
etode similar al que el pilot haur
`
a dâexecutar durant el test de vol.
Els resultats i les observacions extretes a partir de les simulacions realitzades indiquen un
bon funcionament del controlador. La precisi
Ì
o en temps obtinguda en el punt de control
del descens cont
Ì
ınu est
`
a dins els marges de temps rellevants des del punt de vista opera-
cional del controlador. Lâ
Ì
us del motor i els aerofrens ha estat acceptable en els escenaris
amb interfer
`
encies exteriors, i nul en els escenaris sense interfer
`
encies, havent-hi certs
canvis segons lâentorn de simulaci
Ì
o. Les indicacions enviades pel controlador han es-
tat enviades amb una freq
Ì
u
`
encia considerada acceptable pel pilot que no li causaria una
gran c
`
arrega de treball. Aquests i altres resultats obtinguts es mostren al llarg dâaquest
project
A direct role for SNX9 in the biogenesis of filopodia.
Filopodia are finger-like actin-rich protrusions that extend from the cell surface and are important for cell-cell communication and pathogen internalization. The small size and transient nature of filopodia combined with shared usage of actin regulators within cells confounds attempts to identify filopodial proteins. Here, we used phage display phenotypic screening to isolate antibodies that alter the actin morphology of filopodia-like structures (FLS) in vitro. We found that all of the antibodies that cause shorter FLS interact with SNX9, an actin regulator that binds phosphoinositides during endocytosis and at invadopodia. In cells, we discover SNX9 at specialized filopodia in Xenopus development and that SNX9 is an endogenous component of filopodia that are hijacked by Chlamydia entry. We show the use of antibody technology to identify proteins used in filopodia-like structures, and a role for SNX9 in filopodia
Thermolabile Methylenetetrahydrofolate Reductase C677T Polymorphism and Homocysteine Are Risk Factors for Coronary Artery Disease in Moroccan Population
Increased plasma total homocysteine (tHcy) levels have been shown to be a risk factor for coronary artery disease (CAD). The common methylenetetrahydrofolate reductase C677T (MTHFR C677T) polymorphism has been reported to be a strong predictor of mild hyperhomocysteinaemia (HHcy). We assessed whether this mutation was associated with increased risk of CAD and plasma levels of tHcy. We also evaluated interactions between this polymorphism, mild elevated tHcy levels and conventional risk factors of CAD. Method. Using PCR-RFLP analysis, we studied the frequency of the C677T genotypes and its effect on CAD and on tHcy concentrations in 400 subjects without and with CAD angiographically confirmed. There were 210 subjects with CAD and 190 subjects without CAD. Results. The frequencies of the C677T genotypes were 53% (59.5% in controls versus 48.1% in cases), 34.8% (32.1 in controls versus 37.1 in cases), and 11.8% (8.4% in controls versus 14.8% in cases), respectively, for 677CC, 677CT, and 677TT. The genotype frequencies were significantly different between case and control groups (P < .05). The 677T allele enhances the risk of CAD associated to HHcy (P < .01). In multivariate analysis models, MTHFR C677T polymorphism effect on CAD was masked by other risk factors. HHcy was only and independently influenced by MTHFR polymorphism and smoking habits, and it is a strong predictor of CAD independently of conventional risk factors. Conclusion. Our data suggest that HHcy is strongly and independently associated to CAD risk increase; and MTHFR C677T polymorphism and smoking habits were the main predictors of tHcy levels. The CAD risk increase is mainly associated with mild HHcy in 677TT, whereas in 677CT and 677CC it is mainly associated with the conventional risk factors
Cyclin A2 Mutagenesis Analysis: A New Insight into CDK Activation and Cellular Localization Requirements
Cyclin A2 is essential at two critical points in the somatic cell cycle: during S phase, when it activates CDK2, and during the G2 to M transition when it activates CDK1. Based on the crystal structure of Cyclin A2 in association with CDKs, we generated a panel of mutants to characterize the specific amino acids required for partner binding, CDK activation and subcellular localization. We find that CDK1, CDK2, p21, p27 and p107 have overlapping but distinct requirements for association with this protein. Our data highlight the crucial importance of the N-terminal α helix, in conjunction with the α3 helix within the cyclin box, in activating CDK. Several Cyclin A2 mutants selectively bind to either CDK1 or CDK2. We demonstrate that association of Cyclin A2 to proteins such as CDK2 that was previously suggested as crucial is not a prerequisite for its nuclear localization, and we propose that the whole protein structure is involved
A Domain Adaptation Approach to Improve Speaker Turn Embedding Using Face Representation
This paper proposes a novel approach to improve speaker modeling using knowledge transferred from face representation. In particular, we are interested in learning a discriminative metric which allows speaker turns to be compared directly, which is beneficial for tasks such as diarization and dialogue analysis. Our method improves the embedding space of speaker turns by applying maximum mean discrepancy loss to minimize the disparity between the distributions of facial and acoustic embedded features. This approach aims to discover the shared underlying structure of the two embedded spaces, thus enabling the transfer of knowledge from the richer face representation to the counterpart in speech. Experiments are conducted on broadcast TV news datasets, REPERE and ETAPE, to demonstrate the validity of our method. Quantitative results in verification and clustering tasks show promising improvement, especially in cases where speaker turns are short or the training data size is limited
Control of actin polymerization via the coincidence of phosphoinositides and high membrane curvature
The conditional use of actin during clathrin-mediated endocytosis in mammalian cells suggests that the cell controls whether and how actin is used. Using a combination of biochemical reconstitution and mammalian cell culture, we elucidate a mechanism by which the coincidence of PI(4,5)P2 and PI(3)P in a curved vesicle triggers actin polymerization. At clathrin-coated pits, PI(3)P is produced by the INPP4A hydrolysis of PI(3,4)P2, and this is necessary for actin-driven endocytosis. Both Cdc42â
guanosine triphosphate and SNX9 activate N-WASPâWIP- and Arp2/3-mediated actin nucleation. Membrane curvature, PI(4,5)P2, and PI(3)P signals are needed for SNX9 assembly via its PXâBAR domain, whereas signaling through Cdc42 is activated by PI(4,5)P2 alone. INPP4A activity is stimulated by high membrane curvature and synergizes with SNX9 BAR domain binding in a process we call curvature cascade amplification. We show that the SNX9-driven actin comets that arise on human diseaseâassociated oculocerebrorenal syndrome of Lowe (OCRL) deficiencies are reduced by inhibiting PI(3)P production, suggesting PI(3)P kinase inhibitors as a therapeutic strategy in Lowe syndrome.J.L. Gallop is supported by a Wellcome Trust Research Career Development Fellowship (grant WT095829AIA). F. Daste, A. Walrant, J.R. Gadsby, and J. Mason are supported by an H2020 European Research Council Starting Grant (281971) awarded to J.L. Gallop. Gurdon Institute funding is provided by the Wellcome Trust (grant 092096) and Cancer Research UK (grant C6946/A14492). The Swedish Medical Research Council and the Swedish Foundation for Strategic Research supported the work of M.R. Holst and R. Lundmark. S.F. Lee is funded by a Royal Society University Research Fellowship (grant UF120277). M. Mettlen is funded by grant MH73125 to Sandra L. Schmid (University of Texas Southwestern Medical Center)
NADPH oxidase 4 inhibition is a complementary therapeutic strategy for spinal muscular atrophy
IntroductionSpinal muscular atrophy (SMA) is a fatal neurodegenerative disorder, characterized by motor neuron (MN) degeneration and severe muscular atrophy and caused by Survival of Motor Neuron (SMN) depletion. Therapies aimed at increasing SMN in patients have proven their efficiency in alleviating SMA symptoms but not for all patients. Thus, combinational therapies are warranted. Here, we investigated the involvement of NADPH oxidase 4 (NOX4) in SMA-induced spinal MN death and if the modulation of Nox4 activity could be beneficial for SMA patients.MethodsWe analysed in the spinal cord of severe type SMA-like mice before and at the disease onset, the level of oxidative stress and Nox4 expression. Then, we tested the effect of Nox4 inhibition by GKT137831/Setanaxib, a drug presently in clinical development, by intrathecal injection on MN survival and motor behaviour. Finally, we tested if GKT137831/Setanaxib could act synergistically with FDA-validated SMN-upregulating treatment (nusinersen).ResultsWe show that NOX4 is overexpressed in SMA and its inhibition by GKT137831/Setanaxib protected spinal MN from SMA-induced degeneration. These improvements were associated with a significant increase in lifespan and motor behaviour of the mice. At the molecular level, GKT137831 activated the pro-survival AKT/CREB signaling pathway, leading to an increase in SMN expression in SMA MNs. Most importantly, we found that the per os administration of GKT137831 acted synergistically with a FDA-validated SMN-upregulating treatment.ConclusionThe pharmacological inhibition of NOX4 by GKT137831/Setanaxib is neuroprotector and could represent a complementary therapeutic strategy to fight against SMA
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