576 research outputs found
Sponge-associated fungi and their bioactive compounds - the Suberites case
No full textSpecimens of Suberites domuncula that had been cultured in aquaria for 4 weeks were analyzed for their associated fungi. A total of 81 fungal strains belonging to 20 different genera was isolated and identified by morphological and molecular methods. The most frequently isolated taxa were Cladosporium spp., Penicillium spp., Petriella sp., Phialophora spp. and Engyodontium album. Based on chromatographic and mass spectrometric analysis of fungal extracts, as well as on bioassay results, Aspergillus ustus, Penicillium sp., Petriella sp. and Scopulariopsis sp. were selected for in-depth analysis of their natural products. A total of 19 different fungal metabolites, including three new natural products, was isolated and structurally identified. A. ustus yielded two sesquiterpenes, a drimane derivative and deoxyuvidin, as well as a sesterterpene ophiobolin H. The drimane derivative had an ED50 value against L5178Y cells of 1.9 mu g ml(-1) in vitro. The crude extract of Petriella sp. was also strongly cytotoxic against the L5178Y cell line. The cyclic tetrapeptide WF-3161 was primarily responsible for the activity; the ED50 value was <0.1 mu g ml(-1). It was identical to the known compound WF-3161 and had been previously isolated from Petriella guttulata. In addition to WF-3161, three further natural products were obtained and unequivocally identified as new derivatives of infectopyrone by one-and two-dimensional NMR spectroscopy and by mass spectroscopy. Of the new compounds, only dihydroinfectopyrone was active against L5178Y cells; the ED50 value was 0.2 mu g ml(-1). Penicillium sp. yielded the largest number of metabolites. Viridicatin, viridicatol, cyclopenin and cyclopenol suppressed larval growth of the polyphagous pest insect Spodoptera littoralis when incorporated into an artificial diet at an arbitrarily chosen concentration of 237 ppm. Viridicatol was the most active compound and had an ED50 value of ca. 50 ppm. Scopulariopsis sp. yielded three metabolites, including the known acetylcholinesterase inhibitors quinolactacin A1 and A2
Perbandingan Antara Balok Baja Profil WF ( Wide Flange ) Dan Struktur Rangka Baja Siku Dengan Model Gable Frame Pada Skadron 32 TNI AU Abdurahman Saleh Malang
No full textPerkembangan konstruksi modern sudah sangat pesat, terutama konstruksi
baja, baik dari segi metode perencanan yang diterapkan, maupun pembuatan
pabrikasi material yang bermutu dan berkualitas tinggi. Salah satunya adalah
Struktur atap dimana dilakukan modifikasi dari bentuk asli yang bertujuan
menjadikan bentuk yang lebih memiliki daya kekuatan yang lebih besar namun
ringan serta memiliki nilai ekonomis, dan bertujuan untuk estetika pula.
Dalam judul skripsi ini penulis akan membandingkan dua profil baja untuk
kebutuhan balok pada gable frame yaitu profil baja WF dan struktur rangka baja siku
dan T. Dalam studi perbandingan ini, penulis akan merencanakan dimensi profil
yang pas terlebih dahulu. Pada desain penampang profil baja WF dan baja Siku dan
T menggunakan metode LRFD yaitu merupakan metode desain yang diberikan
faktor beban dan faktor reduksi untuk memproleh desain yang aman dan ekonomis,
selain itu untuk memproleh jumlah baut yang dibutuhkan untuk setiap
sambungannya.
Metodelogi yang digunakan adalah studi pustaka dan perencanaan struktur
baja kemudian dengan analisa pembebanan yang telah dihitung dianalisa dengan
program bantu STAAD Pro Vi8 untuk medapatkan nilai-nilai momen, gaya lintang,
dan gaya normal. Sehingga menghasilkan perhitungan struktur dan gambar
perencanaan.
Dari hasil perhitungan dengan pembebanan yang sama didapatkan dimensi
profil WF 700.600.18.34. Didapatkan dimensi profil Siku 130.130.9 dan T 400.300.
Kebutuhan baut untuk sambungan profil WF adalah 112 baut dan profil Siku dan T
adalah 688 baut. Berat struktur balok menggunakan profil WF 700.600.18.34 sebesar
: 37238,4 kg, sedangkan menggunakan profil Siku 130.130.9 dan T 400.300 berat
struktur sebesar : 36545,1 kg. Terdapat selisih berat struktur sebesar 693,3 k
PERBANDINGAN ANTARA BALOK BAJA WF (WIDE FLANGE) DAN BALOK CASTELLA DENGAN MODEL GABLE FRAME PADA HANGGAR PESAWAT SKADRON 32 PANGKALAN MILITER TNI AU ABDURAHMAN SALEH MALANG
No full textPerkembangan konstruksi modern sudah sangat pesat, terutama konstruksi
baja, baik dari segi metode perencanan yang diterpkan, maupun pembuatan pabrikasi
material yang bermutu dan berkualitas tinggi. Salah satunya adalah balok castella
dimana dilakukan modifikasi dari bentuk asli yang bertujuan menjadikan bentuk yang
lebih memiliki daya kekuatan yang lebih besar namun ringan serta memiliki nilai
ekonomis, dan bertujuan untuk estetika pula.
Dalam judul skripsi ini penulis akan membandingkan dua profil baja untuk
kebutuhan balok pada gable frame yaitu profil baja WF dan baja castella. Dalam studi
perbandingan ini, penulis akan merencanakan dimensi profil yang pas terlebih
dahulu. Pada desain penampang profil baja WF dan baja castella menggunakan
metode LRFD yaitu merupakan metode desain yang diberikan faktor beban dan
faktor reduksi untuk memproleh desain yang aman dan ekonomis, selain itu untuk
memproleh jumlah baut yang dibutuhkan untuk setiap sambungannya.
Metodelogi yang digunakan adalah studi pustaka dan perencanaan struktur
baja kemudian dengan analisa pembebanan yang telah dihitung dianalisa dengan
program bantu STAAD Pro Vi8 untuk medapatkan nilai-nilai momen, gaya lintang,
dan gaya normal. Sehingga menghasilkan perhitungan struktur dan gambar
perencanaan.
Dari hasil perhitungan dengan pembebanan yang sama didapatkan dimensi
profil WF 700.600.18.34. Didapatkan dimensi profil Castella 900.600.18.34 yang
berasal dari H beam 600.600.18.34. Kebutuhan baut untuk sambungan dari kedua
profil hampir sama. Berat struktur balok menggunakan WF 700600.18.34 sebesar :
25303,0658 kg .Sedangkan menggunakan Castella 900.600.18.34 berat struktur
sebesar : 24440,8532 kg. Terdapat selisih berat struktur sebesar 862,2126 k
MULTIPHOTON DISSOCIATION AND IONIZATION OF Ni(CO), AND VARIOUS COBALT COMPLEXES IN A JET-COOLED MOLECULAR BEAM: COMPARISON WITH MPI OF WF.
No full textAuthor Institution: Department of Chemistry, University of Illinois at ChicagoMutiphoton ionization spectroscopy of Ni(CO), and various cobalt complexes have been investigated. Their MPI spectra exhibited relatively sharp and narrow peaks, namely atomic lines, in the 410-510nm region. Two-photon resonance ionization spectra of metal atoms have been observed in Ni(CO), and cobalt complexes. The multiphoton process for dissociation and ionization in these complexes will be discussed. However, MPI spectra of WF, have exhibited broad bands over the 450-500nm region. The MPI spectra of WF, are quite different than those of Ni(CO), and cobalt complexes: no atomic bands have been observed. The spectra can be instead assigned to three-photon molecular resonance ionization of WF,. All the MPI spectra observed have been assigned and predicted pathways of the MPD/MPI mechanism have been postulated based on energertic thresholds and a power study. Comparison between molecular MPI and atomic MPI in the supersonic jet expansion will be discussed
Tungsten Fibre Reinforced Tungsten (Wf /W) using Yarn Based Textile Preforms
No full textTungsten Fibre Reinforced Tungsten (Wf/W) using Yarn Based Textile PreformsJ.W.Coenena,e,∗,P.Huberb, L.Raumanna, D.Schwalenberga,d, Y.Maoa, J.Rieschc,Ch.Linsmeiera, R.Neuc,da)Forschungszentrum J ̈ulich GmbH, Institut f ̈ur Energie- und Klimaforschung 52425J ̈ulich, Germany,b)Institut f ̈ur Textiltechnik (ITA) der RWTH Aachen University,Aachen, Germany,c)Max-Planck-Institut f ̈ur Plasmaphysik, 85748 Garching,Germany,d)Technische Universit ̈at M ̈unchen, 85748 Garching, Germany,e)Department of Engineering Physics, University of Wisconsin Madison, WI 53706Madison, USAMaterial issues pose a significant challenge for the design of future fusion reactors.Tungsten (W) is the main candidate material as it is resilient against erosion, has thehighest melting point of any metal and shows rather benign transmutations under neu-tron irradiation. However, W is intrinsically brittle and faces operational embrittlement.To overcome these issues new advanced materials are being developed. W-fibre re-inforced W-composite material (Wf/W) incorporates extrinsic toughening mechanismsallowing the redistribution of stress peaks and thus allowing steps towards applica-tion in a future fusion reactor. Recently progress has been made towards fully densemulti short-fibre powder metallurgical production of Wf/W [2] as well as optimising theprocess understanding for the routes using chemical deposition [3].In this contribution the recent status for the Wf/W production will be given with a focuson the introduction of advanced textile preforms produced from W-yarns [1]. In thepast, typically monofilamantes with a diameter of150μm(OSRAM) have been used toweave textile preforms to facilitate large scale production of e.g. for CVD-Wf/W [3].However, the high stiffness of the tungsten fibers with 150 um diameter oftenpresents some challenges, i.e. positioning of a flat preform during the CVD processes.Here less stiff16μmor25μmfibres can be used where the strength of the16μmfibresis at4500MPa[3] and thus significant higher than the strength of the150μmfibre.After the initial success in yarn production [1] a larger amount of yarns were indus-trially produced at Bossert&Kast and used for Weaving. The superior weavability ofthe yarn allows a much more flexible textile preform to be manufactured. Here threetypes of weaves are being compared, firstly of course the original monofilamant basedweave and then the yarn based options utilising first a classical50μmtungsten fila-ment in the weft direction and a second one utilising the identical yarn type in bothwarp and weft direction. Testing of these weaves in the CVD (Wf/W) production isessential to optimise density and fibre volume fraction.For the individual yarns already a dense infiltration is observed and needs nowto be established for the woven product. Modelling shows that utilising a yarn basedweave and thus making the layer placement more accurate, which is crucial to allowWf/W production with optimal density and mechanical properties.[1] Coenen J.W. et al.Physica Scripta, IOP, T171, 014061, (2020).[2] Mao, Y. et al.Composites Part A:,Elsevier BV, 2018, 107, 342-353.[3] Gietl, H. et al.Journal of Composite Materials, (2018), 002199831877114.∗Corresponding Author: tel +492461615536 e-mail [email protected]
Corn-bran: Alternative cellulosic filler for polypropylene
No full textIn this study, the use-ability of corn bran (CB) as a reinforcing filler in polypropylene (PP) matrix was investigated. The properties of CB/PP composites were compared with wood fiber (WF) filled PP composites. In order to enhance the interfacial adhesion, maleated-PP (PP-g-MAH) (MaPP) was used. The CB/PP and WF/PP composites were compounded in an Xplore laboratory compounder. The CB/PP/MaPP and WF/PP/MaPP composites were characterized by tensile test, differential scanning calorimetry (DSC), thennogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The morphology investigated by scanning electron microscopy (SEM). It was shown that corn bran can be an alternative candidate to be used as a reinforcing natural filler source for thermoplastic composites
Optimal design of water distribution systems based on entropy and topology
No full textA new multi-objective evolutionary optimization approach for joint topology and pipe size design of water distribution systems is presented. The algorithm proposed considers simultaneously the adequacy of flow and pressure at the demand nodes; the initial construction cost; the network topology; and a measure of hydraulic capacity reliability. The optimization procedure is based on a general measure of hydraulic performance that combines statistical entropy, network connectivity and hydraulic feasibility. The topological properties of the solutions are accounted for and arbitrary assumptions regarding the quality of infeasible solutions are not applied. In other words, both feasible and infeasible solutions participate in the evolutionary processes; solutions survive and reproduce or perish strictly according to their Pareto-optimality. Removing artificial barriers in this way frees the algorithm to evolve optimal solutions quickly. Furthermore, any redundant binary codes that result from crossover or mutation are eliminated gradually in a seamless and generic way that avoids the arbitrary loss of potentially useful genetic material and preserves the quality of the information that is transmitted from one generation to the next. The approach proposed is entirely generic: we have not introduced any additional parameters that require calibration on a case-by-case basis. Detailed and extensive results for two test problems are included that suggest the approach is highly effective. In general, the frontier-optimal solutions achieved include topologies that are fully branched, partially- and fully-looped and, for networks with multiple sources, completely separate sub-networks
Long-term warfarin therapy and biomarkers for osteoporosis and atherosclerosis
No full textAbstractBackgroundStroke prevention by warfarin, a vitamin K antagonist, has been an integral part in the management of atrial fibrillation. Vitamin K-dependent matrix Gla protein (MGP) has been known as a potent inhibitor of arterial calcification and osteoporosis. Therefore, we hypothesized that warfarin therapy affects bone mineral metabolism, vascular calcification, and vascular endothelial dysfunction.MethodsWe studied 42 atrial fibrillation patients at high-risk for atherosclerosis having one or more coronary risk factors. Twenty-four patients had been treated with warfarin for at least 12months (WF group), and 18 patients without warfarin (non-WF group). Bone alkaline phosphatase (BAP) and under carboxylated osteocalcin (ucOC) and receptor activator of nuclear factor-kappa B ligand (RANKL) were measured as bone metabolism markers. Reactive hyperemia-peripheral arterial tonometry (RH-PAT) index measured by Endo-PAT2000 was used as an indicator of vascular endothelial function.ResultsThere were no significant differences in patient background characteristics and other clinical indicators between the two groups. In WF group, the ucOC levels were significantly higher than those in the non-WF group (10.3±0.8 vs. 3.4±0.9ng/mL; P<0.01), similarly, the RANKL levels in the WF group were higher than those in the non-WF group (0.60±0.06 vs. 0.37±0.05ng/mL; P=0.007). Moreover, RH-PAT index was significantly lower in the WF group compared to those in the non-WF group (1.48±0.11 vs. 1.88±0.12; P=0.017).ConclusionsLong-term warfarin therapy may be associated with bone mineral loss and vascular calcification in 60–80year old hypertensive patients
Closed-loop model-based wind farm control using FLORIS under time-varying inflow conditions
No full textWind farm (WF) controllers adjust the control settings of individual turbines to enhance the total performance of a wind farm. Most WF controllers proposed in the literature assume a time-invariant inflow, whereas important quantities such as the wind direction and speed continuously change over time in reality. Furthermore, properties of the inflow are often assumed known, which is a fundamentally compromising assumption to make. This paper presents a novel, closed-loop WF controller that continuously estimates the inflow and maximizes the energy yield of the farm through yaw-based wake steering. The controller is tested in a high-fidelity simulation of a 6-turbine wind farm. The WF controller is stress-tested by subjecting it to strongly-time-varying inflow conditions over 5000 s of simulation. A time-averaged improvement in energy yield of 1.4% is achieved compared to a baseline, greedy controller. Moreover, the instantaneous energy gain is up to 11% for wake-loss-heavy situations. Note that this is the first closed-loop and model-based WF controller tested for time-varying inflow conditions (i.e., where the mean wind direction and wind speed change over time) at such fidelity. This solidifies the WF controller as the first realistic closed-loop control solution for yaw-based wake steering.Team Jan-Willem van Wingerde
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