425 research outputs found

    Economic Viability of the Use of Local Pseudo-Oils for Drilling Fluid Formulation

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    The initial cost of formulating Synthetic Base Muds (SBM) compared to conventional Oil Base Muds (OBM) may be doubled but after considering the cost of containment, hauling, and disposal of OBM after use, the cost of using SBM becomes relatively cheaper. The formulation and disposal options (onshore and offshore) and the cost benefit of using seven local antioxidated pseudo-oils (vegetable esters) SBM compared to commercial OBM at an average offshore and onshore temperature operations were simulated in this work using API standard performance benchmarks. The average cost percent of savings on the use of the seven local vegetable oils over the use of commercial synthetic base fluid offshore and onshore were 48.32% and 56.30% respectively. Thus the use of local ester oils for drilling fluids formulation are more economical compared to currently imported oil based drilling fluids. The cultivation and production of these local pseudo-oils are on the increase guaranteeing its adoption and application to be very sustainable.Keywords: Antioxidants, Disposals, Economics, Esters, Formulation

    Pengaruh Penggantian Sebagian Agregat Halus Dengan Kertas Koran Bekas Pada Campuran Batako Semen Portland Terhadap Kuat Tekan Dan Serapan Air

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    Ketersedian material alam untuk konstruksi sangatlah terbatas, di lain pihak permintaan akanmaterial tersebut terus meningkat, sehingga perlu dicoba untuk menggunakan materialalternatif seperti memanfaatkan barang bekas yang sering menjadi sampah sebagai materialkonstruksi. Salah satu alternatif yang dicoba adalah kertas koran bekas sebagai materialtambahan dalam campuran batako semen portland untuk menggantikan sebagian pasir,sehingga dapat mengurangi pemakaian pasir dan diharapkan dapat mengurangi sampah sertadiperoleh batako semen portland yang memiliki bobot lebih ringan. Penelitian dilakukandengan membuat batako semen portland berlubang (hollow block) berdimensi 40 x 20 x 10cm yang terdiri dari batako semen portland normal (tanpa penggantian pasir dengan kertaskoran) dan batako semen portland dengan penggantian pasir dengan kertas koran masingmasingsebanyak 15%, 20%, 25% dan 30% volume pasir. Hasil penelitian menunjukanbahwa penambahan kertas koran bekas dalam campuran batako semen portland untukmenggantikan sebagian pasir mengakibatkan penurunan nilai kuat tekan dan peningkatannilai penyerapan air (absorpsi). Kuat tekan batako semen portland normal pada umur 28 hariadalah sebesar 6,71 MPa, nilai ini menurun menjadi berturut-turut sebesar 6,51 MPa, 5,90MPa, 5,08 MPa dan 4,51 MPa pada penambahan kertas koran sebesar 15%, 20%, 25% dan30% volume pasir sedangkan absorpsinya masing masing 8,43%, 8,72%, 9,18% dan 10,36%pada penambahan kertas koran berturut-turut sebesar 15%, 20%, 25% dan 30% volume pasir,lebih tinggi dari batako tanpa penambahan kertas yaitu 6.53

    Stepped vitrification technique for human ovarian tissue cryopreservation

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    The advantage of stepped vitrification (SV) is avoiding ice crystal nucleation, while decreasing the toxic effects of high cryoprotectant concentrations. We aimed to test this method for human ovarian tissue cryopreservation. Ovarian cortex was taken from 7 fertile adult women. Samples were subjected to an SV protocol performed in an automatic freezer, which allowed sample transfer to ever higher concentrations of dimethyl sulfoxide (DMSO) as the temperature was reduced. Histological evaluation of the vitrified-warmed tissue showed large numbers of degenerated follicles after 24 hours of in vitro culture. We therefore evaluated DMSO perfusion rates by X-ray computed tomography, ice crystal formation by freeze-substitution, and cell toxicity by transmission electron microscopy, seeking possible reasons why follicles degenerated. Although cryoprotectant perfusion was considered normal and no ice crystals were formed in the tissue, ultrastructural analysis detected typical signs of DMSO toxicity, such as mitochondria degeneration, alterations in chromatin condensation, cell vacuolization and extracellular matrix swelling in both stromal and follicular cells. The findings indicated that the method failed to preserve follicles due to the high concentrations of DMSO used. However, adaptations can be made to avoid toxicity to follicles caused by elevated levels of cryoprotectants.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) 2016/22947-

    Establishing the ACORN national practitioner database: Strategies to recruit practitioners to a national practice-based research network

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    Objectives The purpose of this paper is to report on the recruitment and promotion strategies employed by the Australian Chiropractic Research Network (ACORN) project aimed at helping recruit a substantial national sample of participants and to describe the features of our practice-based research network (PBRN) design that may provide key insights to others looking to establish a similar network or draw on the ACORN project to conduct sub-studies. Methods The ACORN project followed a multifaceted recruitment and promotion strategy drawing on distinct branding, a practitioner-focused promotion campaign, and a strategically designed questionnaire and distribution/recruitment approach to attract sufficient participation from the ranks of registered chiropractors across Australia. Results From the 4684 chiropractors registered at the time of recruitment, the project achieved a database response rate of 36% (n = 1680), resulting in a large, nationally representative sample across age, gender, and location. This sample constitutes the largest proportional coverage of participants from any voluntary national PBRN across any single health care profession. Conclusions It does appear that a number of key promotional and recruitment features of the ACORN project may have helped establish the high response rate for the PBRN, which constitutes an important sustainable resource for future national and international efforts to grow the chiropractic evidence base and research capacity. Further rigorous enquiry is needed to help evaluate the direct contribution of specific promotional and recruitment strategies in attaining high response rates from practitioner populations who may be invited to participate in future PBRNs

    The GRAVITY fringe tracker: correlation between optical path residuals and atmospheric parameters

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    After the first year of observations with the GRAVITY fringe tracker, we compute correlations between the optical path residuals and atmospheric and astronomical parameters. The median residuals of the optical path residuals are 180 nm on the ATs and 270 nm on the UTs. The residuals are uncorrelated with the target magnitudes for Kmag below 5.5 on ATs (9 on UTs). The correlation with the coherence time is however extremely clear, with a drop-off in fringe tracking performance below 3 ms.Comment: submitted to SPIE Astronomical Telescopes & Instrumentation 201

    Establishing the ACORN National Practitioner Database: Strategies to Recruit Practitioners to a National Practice-Based Research Network.

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    ObjectivesThe purpose of this paper is to report on the recruitment and promotion strategies employed by the Australian Chiropractic Research Network (ACORN) project aimed at helping recruit a substantial national sample of participants and to describe the features of our practice-based research network (PBRN) design that may provide key insights to others looking to establish a similar network or draw on the ACORN project to conduct sub-studies.MethodsThe ACORN project followed a multifaceted recruitment and promotion strategy drawing on distinct branding, a practitioner-focused promotion campaign, and a strategically designed questionnaire and distribution/recruitment approach to attract sufficient participation from the ranks of registered chiropractors across Australia.ResultsFrom the 4684 chiropractors registered at the time of recruitment, the project achieved a database response rate of 36% (n = 1680), resulting in a large, nationally representative sample across age, gender, and location. This sample constitutes the largest proportional coverage of participants from any voluntary national PBRN across any single health care profession.ConclusionsIt does appear that a number of key promotional and recruitment features of the ACORN project may have helped establish the high response rate for the PBRN, which constitutes an important sustainable resource for future national and international efforts to grow the chiropractic evidence base and research capacity. Further rigorous enquiry is needed to help evaluate the direct contribution of specific promotional and recruitment strategies in attaining high response rates from practitioner populations who may be invited to participate in future PBRNs

    Hamilton-Jacobi theory for Hamiltonian systems with non-canonical symplectic structures

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    A proposal for the Hamilton-Jacobi theory in the context of the covariant formulation of Hamiltonian systems is done. The current approach consists in applying Dirac's method to the corresponding action which implies the inclusion of second-class constraints in the formalism which are handled using the procedure of Rothe and Scholtz recently reported. The current method is applied to the nonrelativistic two-dimensional isotropic harmonic oscillator employing the various symplectic structures for this dynamical system recently reported.Comment: 17 pages, no figure

    First Results from the KMOS Lens-Amplified Spectroscopic Survey (KLASS): Kinematics of Lensed Galaxies at Cosmic Noon

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    We present the first results of the KMOS Lens-Amplified Spectroscopic Survey (KLASS), a new ESO Very Large Telescope (VLT) large program, doing multi-object integral field spectroscopy of galaxies gravitationally lensed behind seven galaxy clusters selected from the HST Grism Lens-Amplified Survey from Space (GLASS). Using the power of the cluster magnification we are able to reveal the kinematic structure of 25 galaxies at 0.7z2.30.7 \lesssim z \lesssim 2.3, in four cluster fields, with stellar masses 8log(M/M)118 \lesssim \log{(M_\star/M_\odot)} \lesssim 11. This sample includes 5 sources at z>1z>1 with lower stellar masses than in any previous kinematic IFU surveys. Our sample displays a diversity in kinematic structure over this mass and redshift range. The majority of our kinematically resolved sample is rotationally supported, but with a lower ratio of rotational velocity to velocity dispersion than in the local universe, indicating the fraction of dynamically hot disks changes with cosmic time. We find no galaxies with stellar mass <3×109M<3 \times 10^9 M_\odot in our sample display regular ordered rotation. Using the enhanced spatial resolution from lensing, we resolve a lower number of dispersion dominated systems compared to field surveys, competitive with findings from surveys using adaptive optics. We find that the KMOS IFUs recover emission line flux from HST grism-selected objects more faithfully than slit spectrographs. With artificial slits we estimate slit spectrographs miss on average 60% of the total flux of emission lines, which decreases rapidly if the emission line is spatially offset from the continuum.Comment: Accepted for publication in Ap

    O vírus da queima do broto da soja no Brasil: etiologia, epidemiologia e controle.

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    Caracteristicas do virus; Modo de transmissao; Sintomas; Epidemiologia e controle; Distribuicao no Brasil e plantas hospedeiras; Danos e controle.bitstream/item/60659/1/Documentos-85.pd

    Inferences on the Timeline of Reionization at z~8 From the KMOS Lens-Amplified Spectroscopic Survey

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    Detections and non-detections of Lyman alpha (Lyα\alpha) emission from z>6z>6 galaxies (<1<1 Gyr after the Big Bang) can be used to measure the timeline of cosmic reionization. Of key interest to measuring reionization's mid-stages, but also increasing observational challenge, are observations at z > 7, where Lyα\alpha redshifts to near infra-red wavelengths. Here we present a search for z > 7.2 Lyα\alpha emission in 53 intrinsically faint Lyman Break Galaxy candidates, gravitationally lensed by massive galaxy clusters, in the KMOS Lens-Amplified Spectroscopic Survey (KLASS). With integration times of ~7-10 hours, we detect no Lyα\alpha emission with S/N>5 in our sample. We determine our observations to be 80% complete for 5σ\sigma spatially and spectrally unresolved emission lines with integrated line flux >5.7×1018>5.7\times10^{-18} erg s1^{-1} cm2^{-2}. We define a photometrically selected sub-sample of 29 targets at z=7.9±0.6z=7.9\pm0.6, with a median 5σ\sigma Lyα\alpha EW limit of 58A. We perform a Bayesian inference of the average intergalactic medium (IGM) neutral hydrogen fraction using their spectra. Our inference accounts for the wavelength sensitivity and incomplete redshift coverage of our observations, and the photometric redshift probability distribution of each target. These observations, combined with samples from the literature, enable us to place a lower limit on the average IGM neutral hydrogen fraction of >0.76  (68%),  >0.46  (95%)> 0.76 \; (68\%), \; > 0.46 \; (95\%) at z ~ 8, providing further evidence of rapid reionization at z~6-8. We show that this is consistent with reionization history models extending the galaxy luminosity function to MUV12M_\textrm{UV} \lesssim -12, with low ionizing photon escape fractions, fesc15%f_\textrm{esc} \lesssim 15\%.Comment: Accepted for publication in MNRA
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