Prediction of industrial debutanizer column compositions using data-driven ANFIS- and ANN-based approaches

Neural Computing and Applications - The work in this paper is based on an industrial debutanizer column in a petroleum refinery located in Malaysia, which produces LPG (liquefied petroleum gas) as...     

Fabrication of Bone Scaffolds from Cockle Shell Waste

Bone scaffold is a three‐dimensional structure composed of materials that could enhance bone regeneration. Bone scaffolds were prepared using freeze‐drying by varying the cockle shell powder concentration where sodium alginate acted as matrix. The scaffolds were then characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, texture analyzer, and liquid displacement method. The bioactivity of the scaffolds was evaluated by immersion into a simulated body fluid solution. Cockle shell powder concentrations affected the bone scaffold characteristics. The increment of the powder concentrations improved the physicochemical properties and bioactivity of the scaffolds.     

LC–DAD–ESIMS/MS characterization of antioxidant and anticholinesterase constituents present in the active fraction from Persicaria hydropiper

Persicaria hydropiper or ‘kesum’ is a herb used extensively as flavoring agent in food. The antioxidant activity was evaluated by measuring the hydroperoxide production resulting from linoleic acid oxidation using ferric thiocyanate (FTC) as well as the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability. Moreover, inhibition activity against cholinesterase, an enzyme that responsible in several physio-pathological processes, was also determined. Identification of phytochemical constituents in the bioactive fraction of P. hydropiper was carried out by LC–DAD–ESIMS/MS technique. Fifteen compounds were identified including flavonoids, flavonoid glycosides and phenylpropanoid glycosides. Six of the compounds were isolated and their structures were elucidated in order to confirm their identities. The antioxidant and antiacetylcholinesterase activities of the isolated compounds were also evaluated.     

Greener photocatalysts: Hydroxyapatite derived from waste mussel shells for the photocatalytic degradation of a model azo dye wastewater

This paper demonstrates for the first time the feasibility of utilising waste mussel shells for the synthesis of hydroxyapatite, Ca₁₀(PO₄)₆(OH)₂ (denoted as HAP) to be used as a greener, renewable photocatalyst for recalcitrant wastewater remediation. HAP was synthesised from Perna canaliculus (green-lipped mussel) shells using a novel pyrolysis–wet slurry precipitation process. The physicochemical properties of the HAP were characterised using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The HAP produced was of comparable quality to commercial (Sulzer Metco) HAP. The synthesised HAP had good photocatalytic activity, whereby methylene blue (a model textile wastewater compound) and its azo dye breakdown products were degraded with an initial rate of 2.5 × 10⁻⁸ mol L⁻¹ min⁻¹. The overall azo dye degradation was nearly 54% within 6 h and 62% within 24 h in an oxygen saturated feed in a batch reactor using a HAP concentration of 2.0 g/L, methylene blue concentration of 5 mg L⁻¹, UV irradiation wavelength of 254 nm and a stirring speed of 300 rpm. The kinetics were well described by three first order reactions in series, reflecting the reaction pathway from methylene blue to azo dye intermediates, then to smaller more highly oxidised intermediates and finally degradation of the recalcitrants. The final two steps of the reaction had significantly slower rates than the initial step (rates constants of 6.2 × 10⁻³ min⁻¹, 1.2 × 10⁻³ min⁻¹ and approximately (due to limited data points) 1.6 × 10⁻⁴ min⁻¹ for the first, second and third step respectively), which tie in with this mechanism, however it could also indicate that the reaction is either product inhibited and/or affected by catalyst deactivation. FTIR analysis of the post-reaction HAP revealed surface PO₄³⁻ group loss. Since there is good photocatalytic activity with oxygen in limited and excess supply during the photoreaction, this indicates the possibility of lattice oxygen participation in the photocatalytic reaction, which needs to be characterised more fully. However, overall, these results indicate that the HAP derived from the mussel shells is a promising greener, renewable photocatalyst for the photocatalytic degradation of wastewater components.     

Neural network applications in fault diagnosis and detection: an overview of implementations in engineering-related systems

The use of artificial neural networks (ANN) in fault detection analysis is widespread. This paper aims to provide an overview on its application in the field of fault identification and diagnosis (FID), as well as the guiding elements behind their successful implementations in engineering-related applications. In most of the reviewed studies, the ANN architecture of choice for FID problem-solving is the multilayer perceptron (MLP). This is likely due to its simplicity, flexibility, and established usage. Its use managed to find footing in a variety of fields in engineering very early on, even before the technology was as polished as it is today. Recurrent neural networks, while having overall stronger potential for solving dynamic problems, are only suggested for use after a simpler implementation in MLP was attempted. Across various ANN applications in FID, it is observed that preprocessing of the inputs is extremely important in obtaining the proper features for use in training the network, particularly when signal analysis is involved. Normalization is practically a standard for ANN use, and likely many other decision-based learning methods due to its ease of use and high impact on speed of convergence. A simple demonstration of ANN’s ease of use in solving a unique FID problem was also shown.

     

Artificial neural networks for automotive air-conditioning systems performance prediction

In this study, ANN model for a standard air-conditioning system for a passenger car was developed to predict the cooling capacity, compressor power input and the coefficient of performance (COP) of the automotive air-conditioning (AAC) system. This paper describes the development of an experimental rig for generating the required data. The experimental rig was operated at steady-state conditions while varying the compressor speed, air temperature at evaporator inlet, air temperature at condenser inlet and air velocity at evaporator inlet. Using these data, the network using Lavenberg–Marquardt (LM) variant was optimized for 4–3–3 (neurons in input–hidden–output layers) configuration. The developed ANN model for the AAC system shows good performance with an error index in the range of 0.65–1.65%, mean square error (MSE) between 1.09 × 10^?5 and 9.05 × 10^?5 and the root mean square error (RMSE) in the range of 0.33–0.95%. Moreover, the correlation which relates the predicted outputs of the ANN model to the experimental results has a high coefficient in predicting the AAC system performance.     

A hybrid formulation and design of model predictive control for systems under actuator saturation and backlash

In this paper, we develop a hybrid design framework of model predictive controller (MPC) for multivariable systems that simultaneously and explicitly addresses the actuator saturation and backlash. The discrete characteristics of the actuator backlash allows us to mathematically express it as a set of mixed-integer linear inequalities constraint in the inputs. As a result, the constrained MPC design is formulated as solving a mixed-integer quadratic programming (MIQP) problem. Furthermore, the proposed MIQP-based design is applied only in the proximity of steady state operating points after locating the active backlash and providing the estimate of the backlash size. Simulation studies are presented to demonstrate how the hybrid MPC performs when applied to an industrial case study of fluid catalytic cracking unit. It is shown that in the presence of actuator saturation and backlash the closed-loop performance can be improved substantially when applying the hybrid method as compared to the traditional design approaches.     

Safe use of hospital information systems: an evaluation model based on a sociotechnical perspective

ABSTRACT

There is growing evidence that shows Hospital Information Systems (HIS) can pose risks to patient safety when they are poorly designed, implemented, or adopted. Most of the preventive solutions have focused on improving the software design, whereas, this study proposes a model for the safe use of HISs based on a sociotechnical perspective. A questionnaire survey was conducted to test the proposed model, in which a total of 364 medical doctors from three Malaysian government hospitals implementing the Total Hospital Information System (THIS) participated. Psychometric testing and factor analysis of the questionnaire instrument established its construct validity and reliability. Structural Equation Modelling (SEM) analysis showed knowledge, system quality, teamwork, and task stressor were the antecedents of safe use of a HIS that predicted the HIS use. In addition, HIS use is a predictor of the HIS use outcomes. Furthermore, HIS use is the mediator between antecedents of safe use of a HIS and the HIS use outcomes. The proposed model has portrayed predictive capability, implying that the model could effectively explain the safe use of a HIS and its outcomes. Hence, the model can provide a basis for evaluating the safe use of a HIS from a sociotechnical standpoint.     

Antioxidant and Xanthine Oxidase Inhibitory Activities of Persicaria hydropiper

Five different polarity fractions of methanolic extract from Persicaria hydropiper, which are consumed as vegetables, were evaluated for its total phenolic content, and antioxidant activities by 1,1-diphenyl-2-picrylhydrazyl radical scavenging, ferric thiocyanate, and xanthine oxidase inhibition assays. Particularly, higher phenolic content was exhibited by butanol and ethyl acetate fractions with the values of 224.38 and 68.95 mg GAE/100 g dry extract, respectively. Both butanol and ethyl acetate fractions exhibited higher 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity with IC₅₀ values of 28.61 and 25.55 μg/ml. Meanwhile, both fractions also were shown to inhibit xanthine oxidase activity compared to other fractions with IC₅₀ values of 28.72 and 165.25 μg/ml. As for the ferric thiocyanate method, all the fractions except hexane fraction showed similar activity against lipid peroxidation and were comparable to butylated hydroxyl toluene, with percentage of inhibition from 95 to 98%.     

Effect of Coir Fibers on the Tensile and Flexural Strength of Soft Marine Clay

The effects of the mechanical properties of the coir fiber which reinforces soft marine clay were investigated by a series of laboratory tests regarding unconfined-compression, indirect tensile properties, and three point bending. In this study, fiber content was found as the main factor that affected the strength of the soil specimens. The results indicated that for the unconfined compression test at the maximum dry density and optimum moisture content, compressive strength increased with fiber content up to 1%. A similar trend was also found in the tensile strength, flexural strength, and young’s modulus of the soil. The strength and ductility increased sharply until the threshold of 1.5% fiber content. Furthermore, the improvement in the mechanical behavior of the soil mixtures indicates that the use of fibers mixed with soft marine clay as potential building materials for land-based structures.