In the production enterprises, the distributed hybrid flow-shop scheduling problems widely exist in the actual production controlling and decision, especially in the production of steel and aluminum. ...Considering the uncertain processing time in the actual production environment, the constraint of deteriorated variable processing time is added in some problems. In this paper, the distributed hybrid flow-shop scheduling problem with deterioration effect (DHFSP-DE) is investigated. The framework of evolutionary multitasking memetic algorithm (MTMA) is designed to address the proposed model. In the proposed method, evolutionary transfer learning is utilized to communicate between two independent DHFSP-DE solvers. The implicit knowledge of the scheduling scheme can be transferred into other solvers to guide the evolution of the population. The memetic algorithm combines a strategy of local intensification with a population-based paradigm. These strategies can capture the implicit knowledge of DHFSP-DE. This paper makes the first attempt to work on the framework of evolutionary multitasking learning for DHFSP-DE problems. The experimental results on the different instances show the effectiveness and efficiency of the proposed MTMA algorithm. Note to Practitioners -The distributed hybrid flow-shop scheduling problem with deterioration effect (DHFSP-DE) is modeled based on the production process of aluminum. The DHFSP-DE is also widely used in the production process of various industries. As the processing time of the job is varied with time, the determined scheduling problem is transformed into a scheduling problem with deterioration effect. This transformation makes the problem even more complicated. The problems are more complex than static problems because they require greater computational dimensionality for evolutionary computation, resulting in the use of computational resources. An evolutionary multitasking memetic algorithm is designed to solve DHFSP-DEs cooperatively. The solutions of the solver can be transferred to other solvers through the mapping of DHFSP-DEs. The transferred solution can affect the evolution process. The efficiency and effectiveness of the proposed MTMA are verified by the comparison experiments. In addition, the MTMA framework can be applied to other scheduling problems.
•Biostimulants can promote post-transplantation growth recovery of horticultural crops.•Biostimulants from different sources have distinct effects on the promotion of seedling growth.•The mode of ...action of different biostimulants depend on plant species and developmental stages.•Biostimulants exert functions in a plant organ-specific mode.
Transplanting shock results in plant growth retardation and developmental delay, and sometimes seedling death. Robust root growth is then critical for transplanted seedlings to survive and re-initiate the growth and development within a short period. Biostimulants have beneficial effects on fostering plant growth and development mainly due to complementary mechanisms. In the present study, we chose three different biostimulants including Radifarm, Acadian and ScanPro to investigate their roles in regulating post-transplantation growth of tomato (Solanum lycopersium L.) and strawberry (Fragaria × ananassa Duch.) seedlings. We observed significant promotion effects of Radifarm on tomato and strawberry underground tissue growth including increased root diameter, surface area and root volume at the early stage after transplanting. Acadian and ScanPro had more significant effects on the promotion of aboveground than underground tissue growth after transplanting including enhanced fresh and dry weights, and plant height. Our clustering analyses and principle component analyses further demonstrated that different biostimulants display distinct impacts on seedling growth, which depends on developmental stages, tissue types and plant species. Specifically, tomato had better responses than strawberry to all three biostimulants, which is probably due to its different root architecture. Our findings reveal that biostimulants facilitate plant post-transplantation growth recovery in a plant-organ specific mode, which suggests the combined application of different biostimulants would achieve better effects.
In this dissertation I undertook two projects, which together aim to push the bounds of our understanding of galaxy evolution and cosmology and prepare for upcoming facilities. For the former, I ...studied the population of strongly lensed, dusty star-forming galaxies who contribute to the majority of star formations at the most intensely star-forming period of the universe. I performed lens modeling and source reconstruction on five of these galaxies and studied the intrinsic size, differential magnification and molecular gas properties of them. I found that the reconstructed region of CO emission is less concentrated than the region emitting dust continuum, and that ignoring the differential magnification effect can bias the estimate of physical properties of interstellar medium of the galaxies. I modified previous visibility-based lens model to work on optical especially the James Webb Space Telescope data, and made the model capable of estimating lens parameters with joint optical and radio data. I tested the new model on simulated observations as well as the Hubble Space Telescope data and the Atacama Large Millimeter/submillimeter Array data of the galaxy SDP.9. The estimated parameters for SDP.9 are consistent with previous analyses based on optical or radio data alone. The techniques developed as part of this work are designed to be applicable to our team's James Webb Space Telescope Early Release Science observations.For the latter, I developed end-to-end cosmological redshift drift simulations. We can in principle measure the history of cosmological expansion through a redshift drift experiment using the Lyman-alpha forest spectra of high-redshift bright quasars. I simulated mock redshift drift observations with spectra from the Sloan Digital Sky Survey and the Keck telescope's High Resolution Echelle Spectrometer to quantify the instrumental requirements for the proposed experiment. In considering the sensitivity of a dedicated facility, I found that redshift drift can be detected via Lyman-alpha forest observation at S/N = 3 (5) in 15 (22) years with a 25 m telescope, given a spectrograph with long term stability with R = 50,000 and an efficiency of 25%.
ABSTRACT
We present APEX-LABOCA 870-μm observations of the fields surrounding the nine brightest high-redshift unlensed objects discovered in the South Pole Telescope’s (SPT) 2500 deg2 survey. ...Initially seen as point sources by SPT’s 1-arcmin beam, the 19-arcsec resolution of our new data enables us to deblend these objects and search for submillimetre (submm) sources in the surrounding fields. We find a total of 98 sources above a threshold of 3.7σ in the observed area of 1300 arcmin2, where the bright central cores resolve into multiple components. After applying a radial cut to our LABOCA sources to achieve uniform sensitivity and angular size across each of the nine fields, we compute the cumulative and differential number counts and compare them to estimates of the background, finding a significant overdensity of $\delta \, {\approx }\,$10 at $S_{870}= 14$ mJy. The large overdensities of bright submm sources surrounding these fields suggest that they could be candidate protoclusters undergoing massive star formation events. Photometric and spectroscopic redshifts of the unlensed central objects range from $z= $3 to 7, implying a volume density of star-forming protoclusters of approximately 0.1 Gpc−3. If the surrounding submm sources in these fields are at the same redshifts as the central objects, then the total star formation rates of these candidate protoclusters reach 10 000 M⊙ yr−1, making them much more active at these redshifts than seen so far in either simulations or observations.
Abstract
With Σ
SFR
∼ 4200
M
⊙
yr
−1
kpc
−2
, SPT 0346–52 (
z
= 5.7) is the most intensely star-forming galaxy discovered by the South Pole Telescope. In this paper, we expand on previous spatially ...resolved studies, using ALMA observations of dust continuum, N
ii
205
μ
m, C
ii
158
μ
m, O
i
146
μ
m, and undetected N
ii
122
μ
m and O
i
63
μ
m emission to study the multiphase interstellar medium (ISM) in SPT 0346–52. We use pixelated, visibility-based lens modeling to reconstruct the source-plane emission. We also model the source-plane emission using the photoionization code
cloudy
and find a supersolar metallicity system. We calculate
T
dust
= 48.3 K and
λ
peak
= 80
μ
m and see line deficits in all five lines. The ionized gas is less dense than comparable galaxies, with
n
e
< 32 cm
−3
, while ∼20% of the C
ii
158
μ
m emission originates from the ionized phase of the ISM. We also calculate the masses of several phases of the ISM. We find that molecular gas dominates the mass of the ISM in SPT 0346–52, with the molecular gas mass ∼4× higher than the neutral atomic gas mass and ∼100× higher than the ionized gas mass.
ABSTRACT
We present Atacama Compact Array and Atacama Pathfinder Experiment observations of the N ii 205 μm fine-structure line in 40 sub-millimetre galaxies lying at redshifts z = 3–6, drawn from ...the 2500 deg2 South Pole Telescope survey. This represents the largest uniformly selected sample of high-redshift N ii 205 μm measurements to date. 29 sources also have C ii 158 μm line observations allowing a characterization of the distribution of the C ii to N ii luminosity ratio for the first time at high redshift. The sample exhibits a median L$_{{\rm{C\,{\small II}}}}$/L$_{{\rm{N\,{\small II}}}}$ ≈ 11.0 and interquartile range of 5.0 –24.7. These ratios are similar to those observed in local (Ultra)luminous infrared galaxies (LIRGs), possibly indicating similarities in their interstellar medium. At the extremes, we find individual sub-millimetre galaxies with L$_{{\rm{C\,{\small II}}}}$/L$_{{\rm{N\,{\small II}}}}$ low enough to suggest a smaller contribution from neutral gas than ionized gas to the C ii flux and high enough to suggest strongly photon or X-ray region dominated flux. These results highlight a large range in this line luminosity ratio for sub-millimetre galaxies, which may be caused by variations in gas density, the relative abundances of carbon and nitrogen, ionization parameter, metallicity, and a variation in the fractional abundance of ionized and neutral interstellar medium.
We present results from end-to-end simulations of observations designed to
constrain the rate of change in the expansion history of the Universe using the
redshift drift of the Lyman-$\alpha$ forest ...absorption lines along the
lines-of-sight toward bright quasars. For our simulations we take
Lyman-$\alpha$ forest lines extracted from Keck/HIRES spectra of bright quasars
at $z>3$, and compare the results from these real quasar spectra with mock
spectra generated via Monte Carlo realizations. We use the results of these
simulations to assess the potential for a dedicated observatory to detect
redshift drift, and quantify the telescope and spectrograph requirements for
these observations. Relative to Liske et al. (2008), two main refinements in
the current work are inclusion of quasars from more recent catalogs and
consideration of a realistic observing strategy for a dedicated redshift drift
experiment that maximizes $\dot{v}/\sigma_{\dot{v}}$. We find that using a
dedicated facility and our designed observing plan, the redshift drift can be
detected at $3\sigma$ significance in 15 years with a 25m telescope, given a
spectrograph with long term stability with $R=50,000$ and 25% total system
efficiency. To achieve this significance, the optimal number of targets is four
quasars, with observing time weighted based upon $\dot{v}/\sigma_{\dot{v}}$ and
object visibility. This optimized strategy leads to a 9% decrease in the
telescope diameter or a 6% decrease in the required time to achieve the same
S/N as for the idealized case of uniformly distributing time to the same
quasars.
SPT0346-52 (z=5.7) is the most intensely star-forming galaxy discovered by the South Pole Telescope, with Sigma_SFR ~ 4200 Msol yr^-1 kpc^-2. In this paper, we expand on previous spatially-resolved ...studies, using ALMA observations of dust continuum, NII205 micron, CII158 micron, OI146 micron, and undetected NII122 micron and OI63 micron emission to study the multi-phase interstellar medium (ISM) in SPT0346-52. We use pixelated, visibility-based lens modeling to reconstruct the source-plane emission. We also model the source-plane emission using the photoionization code CLOUDY and find a supersolar metallicity system. We calculate T_dust = 48.3 K and lambda_peak = 80 micron, and see line deficits in all five lines. The ionized gas is less dense than comparable galaxies, with n_e < 32 cm^-3, while ~20% of the CII158 emission originates from the ionized phase of the ISM. We also calculate the masses of several phases of the ISM. We find that molecular gas dominates the mass of the ISM in SPT0346-52, with the molecular gas mass ~4x higher than the neutral atomic gas mass and ~100x higher than the ionized gas mass.
We present results from end-to-end simulations of observations designed to constrain the rate of change in the expansion history of the Universe using the redshift drift of the Lyman-\(\alpha\) ...forest absorption lines along the lines-of-sight toward bright quasars. For our simulations we take Lyman-\(\alpha\) forest lines extracted from Keck/HIRES spectra of bright quasars at \(z>3\), and compare the results from these real quasar spectra with mock spectra generated via Monte Carlo realizations. We use the results of these simulations to assess the potential for a dedicated observatory to detect redshift drift, and quantify the telescope and spectrograph requirements for these observations. Relative to Liske et al. (2008), two main refinements in the current work are inclusion of quasars from more recent catalogs and consideration of a realistic observing strategy for a dedicated redshift drift experiment that maximizes \(\dot{v}/\sigma_{\dot{v}}\). We find that using a dedicated facility and our designed observing plan, the redshift drift can be detected at \(3\sigma\) significance in 15 years with a 25m telescope, given a spectrograph with long term stability with \(R=50,000\) and 25% total system efficiency. To achieve this significance, the optimal number of targets is four quasars, with observing time weighted based upon \(\dot{v}/\sigma_{\dot{v}}\) and object visibility. This optimized strategy leads to a 9% decrease in the telescope diameter or a 6% decrease in the required time to achieve the same S/N as for the idealized case of uniformly distributing time to the same quasars.
SPT0311-58 is the most massive infrared luminous system discovered so far during the Epoch of Reionization (EoR). In this paper, we present a detailed analysis of the molecular interstellar medium at ...z = 6.9, through high-resolution observations of the CO(6-5), CO(7-6), CO(10-9), CI(2-1), and p-H2O(211-202) lines and dust continuum emission with the Atacama Large Millimeter/submillimeter Array (ALMA). The system consists of a pair of intensely star-forming gravitationally lensed galaxies (labelled West and East). The intrinsic far-infrared luminosity is (16 \(\pm\) 4)\(\times\rm 10^{12} \ \rm L_{\odot}\) in West and (27 \(\pm\) 4)\(\times\rm 10^{11} \ \rm L_{\odot}\) in East. We model the dust, CO, and CI using non-local thermodynamic equilibrium radiative transfer models and estimate the intrinsic gas mass to be (5.4 \(\pm\) 3.4)\(\times\rm 10^{11} \ \rm M_{\odot}\) in West and (3.1 \(\pm\) 2.7)\(\times\rm 10^{10} \ \rm M_{\odot}\) in East. We find that the CO spectral line energy distribution in West and East are typical of high-redshift sub-millimeter galaxies (SMGs). The CO-to-H2 conversion factor (\(\alpha_{CO}\)) and the gas depletion time scales estimated from the model are consistent with the high-redshift SMGs in the literature within the uncertainties. We find no evidence of evolution of depletion time with redshift in SMGs at z > 3. This is the most detailed study of molecular gas content of a galaxy in the EoR to-date, with the most distant detection of H2O in a galaxy without any evidence for active galactic nuclei in the literature.
PDF
