In this study, two different methods were used to introduce functionalized graphene oxide (GO) onto the surface of nanofiltration (NF) membrane to improve its performance for heavy metal removal. The ...first method was based on coating in which the surface of NF membrane was coated with cross-linked GO, while the second method was introducing GO into monomer solution during interfacial polymerization. The efficiency of different methods was then compared by characterizing membrane physiochemical properties, as well as separation performance. With regard to performances, the water flux of TFN-i2 membrane (with GOs incorporated into thin layer) was reported to be 95 L/m
2
h compared to 75 L/m
2
h found in the TFN-c2 membrane (with GOs coated on the surface) at 8 bar. Both modified membranes exhibited higher water flux than the control membrane without GO incorporation (40 L/m
2
h). Although the water flux of TFN-c2 membrane was lower, it achieved higher cobalt removal (97%) than that of TFN-i2 membrane (73%) due to its higher negative surface charge that improved separation via the Donnan exclusion effect.
Graphic abstract
Abstract
We present a new exploration of the cosmic star formation history and dust obscuration in massive galaxies at redshifts 0.5 < z < 6. We utilize the deepest 450- and 850-μm imaging from ...SCUBA-2 CLS, covering 230 arcmin2 in the AEGIS, COSMOS and UDS fields, together with 100–250 μm imaging from Herschel. We demonstrate the capability of the t-phot deconfusion code to reach below the confusion limit, using multiwavelength prior catalogues from CANDELS/3D-HST. By combining IR and UV data, we measure the relationship between total star formation rate (SFR) and stellar mass up to z ∼ 5, indicating that UV-derived dust corrections underestimate the SFR in massive galaxies. We investigate the relationship between obscuration and the UV slope (the IRX–β relation) in our sample, which is similar to that of low-redshift starburst galaxies, although it deviates at high stellar masses. Our data provide new measurements of the total SFR density (SFRD) in $M_{\ast }>10^{10}\,\textrm{M}_{\odot }$ galaxies at 0.5 < z < 6. This is dominated by obscured star formation by a factor of >10. One third of this is accounted for by 450-μm-detected sources, while one-fifth is attributed to UV-luminous sources (brighter than $L_{\rm UV}^\ast$), although even these are largely obscured. By extrapolating our results to include all stellar masses, we estimate a total SFRD that is in good agreement with previous results from IR and UV data at z ≲ 3, and from UV-only data at z ∼ 5. The cosmic star formation history undergoes a transition at z ∼ 3–4, as predominantly unobscured growth in the early Universe is overtaken by obscured star formation, driven by the build-up of the most massive galaxies during the peak of cosmic assembly.
•A multi zone model is applied to investigate the effect of RG on n-heptane combustion.•RG addition retards start of combustion of n-heptane.•Chemical effect of RG is greater than its dilution and ...thermodynamic effects.•H2 has more chemical effects in comparison to CO.•Dilution effect of H2 is close to dilution effect of CO.
Main purpose of this paper is investigating on the effect of reformer gas addition on combustion, performance and emission characteristics of a n-heptane fueled HCCI supercharged engine. A validated multi zone model, which is accurate for modeling of HCCI engine, is used. Heat and mass transfer between zones and convective heat transfer between in-cylinder charge and combustion chamber walls are considered in the multi zone model. A semi detailed chemical kinetics mechanism, containing 57 species and 290 reactions, is used for simulating the combustion process of n-heptane. Four different values of reformer gas are added to the main fuel and its effects on engine performance and chemical reactions are studied. The results show that addition of reformer gas retards the start of combustion and causes to lower in-cylinder peak pressure and temperature. Chemical, dilution and thermodynamic effects of RG are studied and the results show that the chemical effect of reformer gas is more significant than its dilution and thermal effects. Hydrogen in comparison to carbon monoxide has more chemical effects. Chemical analyses show that RG affects the chemical reactions and intermediate species concentration.
We report a stable, Yb-fiber-laser-based, green-pumped, picosecond optical parametric oscillator (OPO) for the near-infrared based on periodically poled potassium titanyl phosphate (PPKTP) nonlinear ...crystal, using fan-out grating design and operating near room temperature. The OPO is continuously tunable across 726-955 nm in the signal and 1201-1998 nm in the idler, resulting in a total signal plus idler wavelength coverage of 1026 nm by grating tuning at a fixed temperature. The device generates up to 580 mW of average power in the signal at 765 nm and 300 mW in the idler at 1338 nm, with an overall extraction efficiency of up to 52% and a pump depletion >76%. The extracted signal at 765 nm and idler at 1746 nm exhibit excellent passive power stability better than 0.5% and 0.8% rms, respectively, over 1 h with good beam quality in TEM
mode profile. The output signal pulses have a Gaussian temporal duration of 13.2 ps, with a FWHM spectral bandwidth of 3.4 nm at 79.5 MHz repetition rate. Power scaling limitations of the OPO due to the material properties of PPKTP are studied.
We report an Yb-fiber-pumped picosecond optical parametric oscillator (OPO) delivering high average power in excellent beam quality throughout the mid-infrared (mid-IR). Using MgO:PPLN as the ...nonlinear crystal and configured as a singly-resonant oscillator in the mid-IR idler wave, the OPO provides up to 3.5 W average power in high spatial quality with M2<1.8 across a continuous tuning range of 4028-2198 nm, with M
<1.5 at 4000 nm. It can also deliver as much as 4.3 W of signal power in an output beam with M2<1.4 across 1446-2062 nm. The extracted idler exhibits a passive power stability better than 0.46% rms over 1 hour across the entire mid-IR tuning range. We have also investigated OPO cavity length detuning behavior about the zero-group-velocity-mismatch crossing point and its effects on output power.
Aims. We present the first public release of photometric redshifts, galaxy rest frame properties and associated magnification values in the cluster and parallel pointings of the first two Frontier ...Fields, Abell-2744 and MACS-J0416. The released catalogues aim to provide a reference for future investigations of extragalactic populations in these legacy fields: from lensed high-redshift galaxies to cluster members themselves. Methods. We exploit a multiwavelength catalogue, ranging from Hubble Space Telescope (HST) to ground-based K and Spitzer IRAC, which is specifically designed to enable detection and measurement of accurate fluxes in crowded cluster regions. The multiband information is used to derive photometric redshifts and physical properties of sources detected either in the H-band image alone, or from a stack of four WFC3 bands. To minimize systematics, median photometric redshifts are assembled from six different approaches to photo-z estimates. Their reliability is assessed through a comparison with available spectroscopic samples. State-of-the-art lensing models are used to derive magnification values on an object-by-object basis by taking into account sources positions and redshifts. Results. We show that photometric redshifts reach a remarkable ~3-5% accuracy. After accounting for magnification, the H-band number counts are found to be in agreement at bright magnitudes with number counts from the CANDELS fields, while extending the presently available samples to galaxies that, intrinsically, are as faint as H~ 32-33, thanks to strong gravitational lensing. The Frontier Fields allow the galaxy stellar mass distribution to be probed, depending on magnification, at 0.5-1.5 dex lower masses with respect to extragalactic wide fields, including sources at M sub(star)~ 10 super(7)-10 super(8)M sub(middot in circle) at z> 5. Similarly, they allow the detection of objects with intrinsic star formation rates (SFRs) >1 dex lower than in the CANDELS fields reaching 0.1-1 M sub(middot in circle)/yr at z~ 6-10.
We report the implementation of a compact cascaded multicrystal scheme based on birefringent crystals in critical phase-matching, for the generation of continuous-wave (cw) radiation in the deep ...ultraviolet (UV). The approach comprises a cascade of 4 single-pass second-harmonic-generation (SHG) stages in β-BaB
O
(BBO) pumped by a single-frequency cw green source at 532 nm. A deep-UV cw output power of 37.7 mW at 266 nm has been obtained with a high passive power stability of 0.12% rms over more than 4 hours. Characterization and optimization of the system in each stage has been systematically performed. Angular phase-matching acceptance bandwidth under tight focusing in BBO, and spectral properties of the deep-UV radiation, have been studied. Theoretical calculations for SHG in the cascaded scheme based on birefringent phase-matching have been performed, and enhancement in UV power compared to single-stage single-pass scheme are studied. Theoretical comparison of BBO with other potential crystals for deep-UV generation in cascaded multicrystal scheme is also presented.
Ultra-faint galaxies are hosted by small dark matter halos with shallow gravitational potential wells, hence their star formation activity is more sensitive to feedback effects. The shape of the ...faint end of the high-z galaxy luminosity function (LF) contains important information on star formation and its interaction with the reionization process during the Epoch of Reionization. High-z galaxies with have only recently become accessible thanks to the Frontier Fields (FFs) survey combining deep HST imaging and the gravitational lensing effect. In this paper we investigate the faint end of the LF at redshift >5 using the data of FFs clusters Abell 2744 (A2744), MACSJ0416.1-2403 (M0416), MACSJ0717.5+3745 (M0717), and MACSJ1149.5+2223 (M1149). We analyze both an empirical and a physically motivated LF model to obtain constraints on a possible turnover of LF at faint magnitudes. In the empirical model the LF drops fast when the absolute UV magnitude is much larger than a turnover absolute UV magnitude . We obtain (15.2) at the 1 (2) confidence level (C.L.) for z ∼ 6. In the physically motivated analytical model, star formation in halos with circular velocity below is fully quenched if these halos are located in ionized regions. Using updated lensing models and new additional FFs data, we re-analyze previous constraints on and fesc presented by Castellano et al. using a smaller data set. We obtain new constraints on km s−1 and fesc 56% (both at 2 C.L.) and conclude that there is no turnover detected so far from the analyzed FFs data. Forthcoming JWST observations will be key to tightening these constraints further.
The present study aimed to determine the status of diabetes distress and its clinical determinants in type II diabetes patients.
This descriptive-analytical study was performed on 220 patients with t ...diabetes referred to Diabetes Clinic of Imam Khomeini Hospital in Ardabil, Iran. The samples were selected using convenience sampling method. Data collection tools included demographic and disease form and Diabetes Mellitus Scale (DDS). Data analysis was performed using SPSS software version 22 via descriptive (frequency, mean, standard deviation) and inferential statistics (compare means, Pearson correlation coefficient and stepwise multiple regression).
The average duration of diabetes was 7.64 (SD = 4.68) years. 63.7% of the patients had moderate to severe diabetes-related distress. Emotional burden dimension had the highest score among the subscales of diabetes distress. In addition, there was a correlation between positive family history (p = 0.017), duration of diabetes (p = 0.028) and type of treatment (p = 0.47) and diabetes distress. HemoglobinA1C levels, body mass index and triglyceride were the major predictors of diabetes distress.
Considering the high prevalence of diabetes distress in patients with type II diabetes, it seems that paying attention to clinical predictors of distress and screening of patients with diabetes is a reasonable and accessible method for health care providers and patients to improve their disease management.
ABSTRACT We exploit a sample of ultra-faint high-redshift galaxies (demagnified Hubble Space Telescope, HST, H160 magnitude > 30) in the Frontier Fields clusters A2744 and M0416 to constrain a ...theoretical model for the UV luminosity function in the presence of photoionization feedback. The objects have been selected on the basis of accurate photometric redshifts computed from multi-band photometry including seven HST bands and deep Ks and IRAC observations. Magnification is computed on an object-by-object basis from all available lensing models of the two clusters. We take into account source detection completeness as a function of luminosity and size, magnification effects, and systematics in the lens modeling of the clusters under investigation. We find that our sample of high-z galaxies constrain the cutoff halo circular velocity below which star formation is suppressed by photoionization feedback to v c cut < 50 km s−1. This circular velocity corresponds to a halo mass of 5.6 × 109 M and 2.3 × 109 M at z = 5 and 10, respectively: higher-mass halos can thus sustain continuous star formation activity without being quenched by external ionizing flux. More stringent constraints are prevented by the uncertainty in the modeling of the cluster lens, as embodied by systematic differences among the lens models available.
PDF
