Synthesis of water networks for industrial parks considering inter-plant allocation

Since an industrial park is a cluster of multiple company individuals, there is requirement to develop specific reuse strategies so as to improve the utilization of resources across plants. This article presents a ‘plant-based’ mode respecting to the water allocation problem within industrial parks. In the mode, mixers and splitters are involved to present the mixing, conveying and splitting operations for reusing streams across plants. Such that, the mixing possibilities can also be investigated and many redundant solutions can be avoided by considering the number limit of inter-plant stream connections at the building stage of network superstructures. On base of this mode, both direct and mixed (direct–indirect) integration scenarios are studied in this study. Superstructures are established and mathematically formulated aiming to minimum fresh water consumption as well as the total annualized cost. At last, three integration cases are explored based on an example from literature for illustration.     

Development of Cloud Movement Prediction Method for Solar Photovoltaic System

Variability of power generation due to the prevalence of cloud cover over solar photovoltaics (PV) power plants is a challenge faced by grid operators and independent system operators (ISOs) in the integration of solar energy into the grid. Solar forecasts generated through ground-based sky imaging systems are useful for short-term cloud motion predictions. However, the cost of sky imaging systems currently available in industries is relatively high. Hence, a ground-based camera system utilizing a simple webcam is proposed in this study. The proposed method can produce predictions with high levels of accuracy. Forecasts were generated through video analysis using MATLAB for the computation of cloud motion predictions. The image processing involved in the implementation of the proposed system is based on the detection of cloud regions in the form of a cluster of white pixels within individual frames and tracking their motion through comparison of subsequent frames. This study describes the techniques and processes used in the development of the proposed method, along with the evaluation of performance through analysis of the results. The predictions were carried out over multiple time horizons. The time horizons selected include 5, 10, 15, 20, 25, and 30 s. The overall results computed showed promising accuracy levels above 94.60%, which makes it adequate for generating reliable forecasts.     

Development of needle-shaped grains from Bi2Sr2CaCu2O8+x with high critical current density suitable for making superconducting wires

We present a grain microstructure for Bi(2212) consisting of only giant needle-shaped grains of around 1.5 mm length and 100 μm diameter. We study the structural and chemical changes suffered by a conventional ceramic Bi(2212) sample in the course of the thermal treatment used to obtain those giant needle-shaped grains. For that, different samples of the same batch were treated with incomplete thermal treatments, and the resulting samples were analysed by using scanning electron microscopy (SEM), optical microscopy, energy dispersed spectroscopy (EDS), inductively coupled plasma (ICP) and X-ray diffraction (XRD). To verify the superconducting nature of the needle-shaped grains, we have performed magnetization, resistivity, and critical current measurements on the original ceramic sample, and on that formed as giant needle-like grains. The critical temperature of these last grains is nearly the same as that of the ceramic sample (T_c∼90 K), which is a high value for the Bi(2212) compound. The critical current density (J_c) of the needle-shaped grains is around 2500 A/cm² at 77 K and in absence of applied magnetic field, a value comparable with that presented for the best wires and thick films. Not only are the shape and the size of these grains very suitable for making superconducting wires, but also the superconducting properties, T_c and J_c, are both high enough to be confident about the possibility of improving the actual Bi(2212) superconducting wires for high current applications.     

Dense graphene nanoplatelet/yttria tetragonal zirconia composites: Processing,hardness and electrical conductivity

Yttria tetragonal zirconia ceramic composites with 1, 2.5, 5 and 10 vol% nominal contents of graphene nanoplatelets (GNPs) were fabricated and characterized. First, the GNP dispersion in isopropanol was optimized to de-agglomerate the GNPs without damaging their structure. Then, submicrometric fully dense composites were obtained via spark plasma sintering (SPS) at 1250 °C with a 5 min holding time. The processing routine produced a nearly homogeneous GNP dispersion in the ceramic matrix, and the GNPs preferential orientation was perpendicular to the sintering compression axis. A ceramic grain refinement due to the GNPs was also detected. The Vickers hardness measured on the plane perpendicular to the sintering compression axis (basal plane) was lower than on the cross sections. This anisotropy increased with the increasing GNP content, while the average hardness decreased. The electrical conductivity was also highly anisotropic, up to seven times higher for the basal planes. The electrical percolation threshold for these composites was estimated to be between 2.2 and 4.4 vol% of the GNP measured content.     

Development of a new in situ test method to measure the air permeability of high performance concretes

Although several in situ techniques, including the Autoclam Permeability System, are available to examine normal concretes (NCs) for this purpose, none are sufficiently sensitive to quantify and distinguish relative high performance concrete (HPC) performance. Therefore, to assess the HPC performance characteristics using the Autoclam air permeability test methodology, two key modifications were investigated and a new test protocol developed. The first modification considered a reduced volume of compressed air applied to the test area (named LV test), and the second an increased test area (named A-75). The reliability of the proposed modifications was investigated by comparing against a laboratory-based gas permeability test method (RILEM air permeability test). Surface resistivity and relative humidity were assessed to evaluate the influence of moisture conditions on in situ air permeability test results. A strong correlation between LV test and RILEM air permeability test results was found when the free moisture near concrete surface regions (up to 20 mm) was removed. It was concluded that the LV test exhibits strong potential to become an established method for assessing in situ HPC permeability.     

Characterization of empty fruit bunch for microwave-assisted pyrolysis

Agricultural waste such as oil palm empty fruit bunch (EFB) is of environmental concern to Malaysia as one of the world’s largest oil palm producers. Pyrolysis can be used to treat biomass waste due to its flexibility in producing solid, liquid and gas products. This study attempts to characterize EFB for pyrolysis using microwaves as an alternative heating source. EFB taken from a local oil palm mill was subjected to fuel, chemical and dielectric property analysis. The findings revealed that high moisture and 47% oxygen gave low calorific value of 16 MJ/kg. Notably, high water content is an advantage in microwave heating as water is a good microwave absorber, which results in fast drying. Further, a high volatile content at 70% gave the EFB an advantage of high reactivity. A moderate potassium content of 12.8% could also positively affect microwave absorption. The dielectric properties of EFB were observed to be proportional to the moisture content. Furthermore, the microwave penetration depth was found highest at 20% moisture, i.e. 3.5 cm. However, low values of both dielectric constant and loss of dried EFBs would require the addition of microwave absorbers for pyrolysis reaction. The fuel and chemical characteristics of EFB were found comparable to other biomasses, which indicated a good candidate for microwave pyrolysis treatment.     

A modified paired t-test for the analysis of plant trials with data autocorrelated in time

Sequential plant performance data, such as daily metal recovery, are shown to follow a first order autoregressive time series model. This has been used to modify the standard formula for the paired t-test in evaluating on-off trials of alternative operating conditions, such as a new flotation reagent or circuit configuration. The modified test is more powerful than the standard test, requiring less trials to reach a decision at a given level of confidence. The power increases with the value of the AR(1) autocorrelation coefficient.The paper gives formulae for the modified test, and for calculating the number of data pairs required to detect a given difference at a particular confidence level. An example of the use of the new test is given.