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The Griffith equation for brittle cracking has three problems. First, it applies to an infinite sheet whereas a laboratory test sample is typically near 100×100mm. Second, it describes a central crack instead of the more dangerous and easily observable edge crack. Third, the theory assumes a uniform stress field, instead of tensile force application used in the laboratory. The purpose of this paper is to avoid these difficulties by employing Gregory's solution in calculating the crack behaviour of PMMA (Poly Methyl Meth Acrylate) discs, pin loaded in tension. Our calculations showed that axial disc loading gave nominal strengths comparable with Griffith theory, but the force went to zero as the crack fully crossed the disc, fitting experimental results. Off-axis loading was more interesting because the predicted strength was lower than in axial testing, but also gave unexpected behaviour at short crack lengths, where nominal strength did not rise indefinitely but dropped as crack length went below D/10, quite different from Griffith, where strength rose continuously as cracks were shortened. Such off-axis loading leads to a size effect in which larger discs are weaker, reminiscent of the fine fibre strengthening phenomenon reported in Griffith's early paper (Griffith 1921 Phil. Trans. R. Soc. Lond. [ABSTRACT FROM AUTHOR]

Objective: The present study aims to evaluate the effects of neuro-linguistic programming (NLP) and guided imagery on postoperative pain and comfort after open-heart surgery.Methods: In the current, prospective, randomized, single-blind clinical study, the participants received NLP with a new behavior formation technique or the guided imagery relaxation technique using an audio compact disc for a duration of 30 min.Results: The patients in the NLP group had significantly lower posttest pain levels, compared to the patients in the guided imagery and control groups. Moreover, the patients in the guided imagery group had significantly higher posttest comfort levels, compared to the patients in the NLP and control groups.Conclusion: The application of both NLP and guided imagery interventions resulted in reduced postoperative pain and increased postoperative comfort levels after open-heart surgery. [ABSTRACT FROM AUTHOR]

The adsorption behavior of different adsorbents has been studied by various research works. But few studies have compared linear and non-linear isotherm and kinetic models alongside phenomenological coefficients. Here, the effect of activated carbon black (ACB) on the methylene blue adsorption behavior of alginate was examined. A low-cost and green adsorbent was fabricated to can easily be detached from water. For this aim waste compact discs were recycled for the preparation of ACB. Loading of 15 wt% ACB related to pure alginate increased removal yield of alginate significantly. Isotherms and kinetic models in linear and non-linear forms were studied and the results were examined by comparing R2 along with different error function values to find the best fitting. The results were well matched with non-linear pseudo-second-order and linear Langmuir. Intraparticle diffusion model and phenomenological coefficients represented control of adsorption by film diffusion and its limiting by pore diffusion. [Display omitted] • It was tried to fabricate a low-cost and non-toxic composite as an adsorbent. • Waste compact discs were used for the preparation of activated carbon black (ACB). • Loading of 15 wt% ACB increased removal yield from 7% to 72%. • Linear and non-linear isotherm and kinetic models were applied for fitting. • Phenomenological coefficients represented control of adsorption by film diffusion. [ABSTRACT FROM AUTHOR]

We provide prescriptions to evaluate the dynamical mass (M dyn) of galaxies from kinematic measurements of stars or gas using analytic considerations and the VELA suite of cosmological zoom-in simulations at z = 1–5. We find that Jeans or hydrostatic equilibrium is approximately valid for galaxies of stellar masses above M ⋆ ∼ 109.5 M⊙ out to 5 effective radii (R e). When both measurements of the rotation velocity v ϕ and of the radial velocity dispersion σ r are available, the dynamical mass |$M_{\rm dyn} \!\simeq \! G^{-1} V_{\rm c}^2 r$|⁠ , can be evaluated from the Jeans equation |$V_{\rm c}^2= v_\phi ^2 + \alpha \sigma _{\rm r}^2$| assuming cylindrical symmetry and a constant, isotropic σ r. For spheroids, α is inversely proportional to the Sérsic index n and α ≃ 2.5 within R e, stars for the simulated galaxies. The prediction for a self-gravitating exponential disc, α = 3.36(r / R e), is invalid in the simulations, where the dominant spheroid causes a weaker gradient from α ≃ 1 at R e, gas to 4 at 5 R e, gas. The correction in α for the stars due to the gradient in σ r(r) is roughly balanced by the effect of the aspherical potential, while the effect of anisotropy is negligible. When only the effective projected velocity dispersion σ l is available, the dynamical mass can be evaluated as |$M_{\rm dyn} = K G^{-1} R_{\rm e} \sigma _{\rm l}^2$|⁠ , where the virial factor K is derived from α , given the inclination and v ϕ/ σ r. We find that the standard value K = 5 is approximately valid only when averaged over inclinations and for compact and thick discs, as it ranges from 4.5 to above 10 between edge-on and face-on projections. [ABSTRACT FROM AUTHOR]

We herein develop a concentration gradient generator (CGG) on a microfluidic chip for diluting different nanoparticles. Specifically designed compact disk (CD)‐shaped microchannels in the CGG module could thoroughly mix the flowing solutions and generate a linear concentration gradient of nanoparticles without aggregation. We combine the CGG with a single‐cell trapper array (SCA) on microfluidics to evaluate the concentration‐dependent bioeffects of the nanoparticles. The precise control of the spatiotemporal generation of nanoparticle concentration on the CGG module and the single‐cell‐level monitoring of the cell behaviors on the SCA module by a high‐content system in real time, render the CGG‐SCA system a highly precise platform, which can exclude the average effect of cell population and reflect the response of individual cells to the gradient concentrations accurately. In addition, the CGG‐SCA system provides an automated platform for high‐throughput screening of nanomedicines with high precision and low sample consumption. [ABSTRACT FROM AUTHOR]

We develop a Bayesian Machine Learning framework called BINGO (Bayesian INference for Galactic archaeOlogy) centred around a Bayesian neural network. After being trained on the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and Kepler asteroseismic age data, BINGO is used to obtain precise relative stellar age estimates with uncertainties for the APOGEE stars. We carefully construct a training set to minimize bias and apply BINGO to a stellar population that is similar to our training set. We then select the 17 305 stars with ages from BINGO and reliable kinematic properties obtained from Gaia DR2. By combining the age and chemo-kinematical information, we dissect the Galactic disc stars into three components, namely the thick disc (old, high-[α/Fe], [α/Fe] ≳ 0.12), the thin disc (young, low-[α/Fe]), and the Bridge, which is a region between the thick and thin discs. Our results indicate that the thick disc formed at an early epoch only in the inner region, and the inner disc smoothly transforms to the thin disc. We found that the outer disc follows a different chemical evolution pathway from the inner disc. The outer metal-poor stars only start forming after the compact thick disc phase has completed and the star-forming gas disc extended outwardly with metal-poor gas accretion. We found that in the Bridge region the range of [Fe/H] becomes wider with decreasing age, which suggests that the Bridge region corresponds to the transition phase from the smaller chemically well-mixed thick to a larger thin disc with a metallicity gradient. [ABSTRACT FROM AUTHOR]

With the rapid development of the Internet, online music has become a new trend. The low cost of access and fast spread speed greatly enriches people's spiritual life, but it also poses great challenges to the protection of intellectual property rights. Nowadays, although the intellectual property rights of music works have been better valued and protected, there are still some problems that limit the development of the music industry and affect the users' experience. For example, the copyrights of different music works may be exclusively represented by different companies, resulting in limited choices for users and vicious competition among music operating companies, which affects the users' experience and is not conducive to the long-term development of the music industry. In order to solve the above problems, we present a decentralized music copyright operation management system based on Blockchain technology. By using the Blockchain's shared ledger mechanism and smart contracts as the basic framework of the Ethereum platform, we realize decentralized music copyright management. The system not only protects copyright better, but also coordinates the interests of creators, copyright owners, operators and users, which is beneficial to the further development of the music industry, and creates more value and better experience for users. [ABSTRACT FROM AUTHOR]

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Phase change materials (PCMs) have long been used as a storage medium in rewritable compact disk and later in random access memory. In recent years, integration of PCMs with nanophotonic structures has introduced a new paradigm for non‐volatile reconfigurable optics. However, the high loss of the archetypal PCM Ge2Sb2Te5 in both visible and telecommunication wavelengths has fundamentally limited its applications. Sb2S3 has recently emerged as a wide‐bandgap PCM with transparency windows ranging from 610 nm to near‐IR. In this paper, the strong optical phase modulation and low optical loss of Sb2S3 are experimentally demonstrated for the first time in integrated photonic platforms at both 750 and 1550 nm. As opposed to silicon, the thermo‐optic coefficient of Sb2S3 is shown to be negative, making the Sb2S3–Si hybrid platform less sensitive to thermal fluctuation. Finally, a Sb2S3 integrated non‐volatile microring switch is demonstrated which can be tuned electrically between a high and low transmission state with a contrast over 30 dB. This work experimentally verifies prominent phase modification and low loss of Sb2S3 in wavelength ranges relevant for both solid‐state quantum emitter and telecommunication, enabling potential applications such as optical field programmable gate array, post‐fabrication trimming, and large‐scale integrated quantum photonic network. [ABSTRACT FROM AUTHOR]

DNA digital storage provides an alternative for information storage with high density and long-term stability. Here, we report the de novo design and synthesis of an artificial chromosome that encodes two pictures and a video clip. The encoding paradigm utilizing the superposition of sparsified error correction codewords and pseudo-random sequences tolerates base insertions/deletions and is well suited to error-prone nanopore sequencing for data retrieval. The entire 254 kb sequence was 95.27% occupied by encoded data. The Transformation-Associated Recombination method was used in the construction of this chromosome from DNA fragments and necessary autonomous replication sequences. The stability was demonstrated by transmitting the data-carrying chromosome to the 100th generation. This study demonstrates a data storage method using encoded artificial chromosomes via in vivo assembly for write-once and stable replication for multiple retrievals, similar to a compact disc, with potential in economically massive data distribution. [ABSTRACT FROM AUTHOR]

W33A is a well-known example of a high-mass young stellar object showing evidence of a circumstellar disc. We revisited the K -band NIFS/Gemini North observations of the W33A protostar using principal components analysis tomography and additional post-processing routines. Our results indicate the presence of a compact rotating disc based on the kinematics of the CO absorption features. The position–velocity diagram shows that the disc exhibits a rotation curve with velocities that rapidly decrease for radii larger than 0.1 arcsec (∼250 au) from the central source, suggesting a structure about four times more compact than previously reported. We derived a dynamical mass of 10.0 |$^{+4.1}_{-2.2}$|   |$\rm {M}_\odot$| for the 'disc + protostar' system, about ∼33 per cent smaller than previously reported, but still compatible with high-mass protostar status. A relatively compact H2 wind was identified at the base of the large-scale outflow of W33A, with a mean visual extinction of ∼63 mag. By taking advantage of supplementary near-infrared maps, we identified at least two other point-like objects driving extended structures in the vicinity of W33A, suggesting that multiple active protostars are located within the cloud. The closest object (Source B) was also identified in the NIFS field of view as a faint point-like object at a projected distance of ∼7000 au from W33A, powering extended K -band continuum emission detected in the same field. Another source (Source C) is driving a bipolar |$\rm {H}_2$| jet aligned perpendicular to the rotation axis of W33A. [ABSTRACT FROM AUTHOR]

This is the problem of the 8th International Experimental Physics Olympiad (EPO8). The task of the EPO8 is to determine Planck constant ħ = h/2p using the given set-up with LED. If you have an idea how to do it, do it and send us the result; skip the reading of the detailed step by step instructions with increasing difficulties. We expect the participants to follow the suggested items – they are instructive for physics education in general. Only the reading of historical remarks given in the first section can be omitted during the Olympiad without loss of generality. Participants should try solving as much tasks as they can without paying attention to the age categories: give your best. [ABSTRACT FROM AUTHOR]

Summary: The performance of a single‐slope solar still system has been improved with the addition of copper oxide (CuO) nanopowder in water as nanofluid and thermoelectric glass cover cooling combination. The use of vibration further enhances the performance of distillate water as a result of the accelerated heat transfer. In this study, CuO nanofluids loaded the solar still system at volume concentrations of 0.5%, 1%, and 1.5%. The design, fabrication, and testing of the single still were conducted under the local weather conditions of Alexandria, which is located in the northwest of Egypt. The proposed solar still had a base area of 1 m2 and fitted with four coiled springs, a DC motor, and a photovoltaic (PV) solar panel. The vibration generator was a three‐phased, with a 1‐HP power motor (220 V, 50 Hz, and 1380 rpm maximum speed) fixed to a compact disk with a small punch for adding masses to generate the un‐mass balance forces. The power source for the DC motor was a 250‐W PV. The daily output of fresh water during the experimental period was empirically measured under the same climate conditions, and the results were compared with those of a conventional solar still. The daily rates of freshwater productivity were investigated in two cases: (a) under vibration without cover cooling and (b) under vibration with cover cooling at the three given nanofluid volume concentrations. Based on the results, the highest daily freshwater productivity attained with the vibration and cover cooling (at the 1.5% nanofluid volume concentration) 7.13, 4.97, and 3.36 kg/day, and the daily efficiency increases by 54%, 43% and 36% compared to the conventional case at the water depths of 10, 20, and 30 mm, respectively, with a maximum estimated cost of 0.027653$/L/m2. [ABSTRACT FROM AUTHOR]

The discovery of optical/UV (ultraviolet) tidal disruption events (TDEs) was surprising. The expectation was that, upon returning to the pericentre, the stellar-debris stream will form a compact disc that will emit soft X-rays. Indeed, the first TDEs were discovered in this energy band. A common explanation for the optical/UV events is that surrounding optically thick matter reprocesses the disc's X-ray emission and emits it from a large photosphere. If accretion follows the super-Eddington mass infall rate, it would inevitably result in an energetic outflow, providing naturally the reprocessing matter. We describe here a new method to estimate, using the observed luminosity and temperature, the mass and energy of outflows from optical transients. When applying this method to a sample of supernovae, our estimates are consistent with a more detailed hydrodynamic modelling. For the current sample of a few dozen optical TDEs, the observed luminosity and temperature imply outflows that are significantly more massive than typical stellar masses, posing a problem to this common reprocessing picture. [ABSTRACT FROM AUTHOR]