Optimization of PERT Network and Compression of Time

In the traditional methods of program evaluation and review technique （PERT） network optimization and compression of time limit for project, the uncertainty of free time difference and total time difference were not considered as well as its time risk. The authors of this paper use the theory of dependent-chance programming to establish a new model about compression of time for project and multi-objective network optimization, which can overcome the shortages of traditional methods and realize the optimization of PERT network directly. By calculating an example with genetic algorithms, the following conclusions are drawn： （ 1 ） compression of time is restricted by cost ratio and completion probability of project; （2） activities with maximal standard difference of duration and minimal cost will be compressed in order of precedence; （3） there is no optimal solutions but noninferior solutions between chance and cost, and the most optimal node time depends on decision-maker＇s preference.

SINGLE MACHINE SCHEDULING WITH CONTROLLABLE PROCESSING TIMES AND COMPRESSION COSTS ： PROOF OF THEOREMS

Abstract This report is virtually the appendix part of the author's previous paper which includes the proofs for the theorems and lemmas.

Improved version of BTOPMC model and its application in event-based hydrologic simulations

In this paper, a grid-based distributed hydrological model BTOPMC （Block-wise use of TOPMODEL） is introduced, which was developed from the original TOPMODEL. In order to broaden the model＇s application to arid regions, improvement methodology is also implemented. The canopy interception and soil infiltration processes were incorporated into the original BTOPMC to model event-based runoff simulation in large arid regions. One designed infiltration model with application of time compression approximation method is emphasized and validated for improving model＇s performance for event hydrological simulations with a case study of Lushi River basin.

Physico-chemical Characteristics of Wet-milled Ultrafine-granulated Phosphorus Slag as a Supplementary Cementitious Material

The phosphorus slag（PS） can be used as a supplementary cementitious material due to its potential hydrating activity. However, its usage has been limited by its adverse effects, including prolonged setting and lowered early-stage strength. In this study, we achieved ultrafine granulation of PS using wetmilling（reducing d50 to as low as 2.02 μm） in order to increase its activity, and examined the physico-chemical properties of the resulting materials, including particle-size distribution, slurry pH, zeta potential, and activity index, as well as how their replacement level and granularity affect the setting time and mechanical performance of PS-cement mixture systems. The results suggested that as the granularity increases, there are significant boosts in the uniformity of particle sizes, slurry pH, and activity index, and the effects on cement paste, including setting times, and early-and late-stage strengths, are significantly mitigated. When d（50）=2.02 μm, the slurry becomes strongly alkaline（pH=12.16） compared to the initial d（50）=20.75 μm（pH=9.49）, and the activity is increased by 73%; when used at 40% replacement, the PS-cement mixture system can reach a 28 d compressive strength of 93.2 MPa, 36% higher than that of the pure cement control group.

Reconstruction and transmission of astronomical image based on compressed sensing

In the process of image transmission, the famous JPEG and JPEG-2000 compression methods need more transmission time as it is difficult for them to compress the image with a low compression rate. Recently the compressed sensing（CS） theory was proposed, which has earned great concern as it can compress an image with a low compression rate, meanwhile the original image can be perfectly reconstructed from only a few compressed data. The CS theory is used to transmit the high resolution astronomical image and build the simulation environment where there is communication between the satellite and the Earth. Number experimental results show that the CS theory can effectively reduce the image transmission and reconstruction time. Even with a very low compression rate, it still can recover a higher quality astronomical image than JPEG and JPEG-2000 compression methods.

Effects of LiAl-Layered Double Hydroxides on Early Hydration of Calcium Sulphoaluminate Cement Paste

As a 3D micro-nano material, layered double hydroxides have been widely used in many fields, especially for reinforced composite materials. In this paper, Li Al-LDHs was obtained by a hydrothermal method. In order to investigate the effects of Li Al-LDHs on the early hydration of calcium sulphoaluminate（CSA） cement paste, compressive strength, setting time and hydration heat were tested while X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FT-IR）, scaning electron microscopy（SEM） and differential scanning calorimetry（DSC） analysis were employed. The results indicated that Li Al-LDHs could significantly improve the early compressive strength and shorten the setting time of calcium sulphoaluminate cement paste with 3 wt% concentration. Besides, the hydration exothermic rate within 5h was accelerated with increasing Li Al-LDHs content. Moreover, the addition of Li Al-LDHs did not result in the formation of a new phase, but increased the quantity of hydration products providing higher compressive strength, shorter setting time and denser microstructure.