Multivariate statistical process monitoring using classical multidimensional scaling

A new Multivariate Statistical Process Monitoring (MSPM) system, which comprises of three main frameworks, is proposed where the system utilizes Classical Multidimensional Scaling (CMDS) as the main multivariate data compression technique instead of using the linearbased Principal Component Analysis (PCA). The conventional method which usually applies variance-covariance or correlation measure in developing the multivariate scores is found to be inappropriately used especially in modelling nonlinear processes, where a high number of principal components will be typically required. Alternatively, the proposed method utilizes the inter-dissimilarity scales in describing the relationships among the monitored variables instead of variance-covariance measure for the multivariate scores development. However, the scores are plotted in terms of variable structure, thus providing different formulation of statistics for monitoring. Nonetheless, the proposed statistics still correspond to the conceptual objective of Hotelling’s T2 and Squared Prediction Errors (SPE). The first framework corresponds to the original CMDS framework, whereas the second utilizes Procrustes Analysis (PA) functions which is analogous to the concept of loading factors in PCA for score projection. Lastly, the final framework employs dynamic mechanism of PA functions as an alternative for enhancing the procedures of the second approach. A simulated system of Continuous Stirred Tank Reactor with Recycle (CSTRwR) has been chosen for the demonstration and the fault detection results were comparatively analyzed to the outcomes of PCA on the grounds of false alarm rates, total number of detected cases and also total number of fastest detection cases. The last two performance factors are obtained through fault detection time. The overall outcomes show that the three CMDS-based systems give almost comparable performances to the linear PCA based monitoring systemwhen dealing the abrupt fault events, whereas the new systems have demonstrated significant improvement over the conventional method in detecting incipient fault cases. More importantly, this monitoring accomplishment can be efficiently executed based on lower compressed dimensional space compared to the PCA technique, thus providing much simpler solution. All of these evidences verified that the proposed approaches are successfully developed conceptually as well as practically for monitoring while complying fundamentally with the principles and technical steps of the conventional MSPM system.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

REE-Ion adsorption clay type deposit characteristics in kuantan’s weathered granite profiles

Kuantan district, Pahang is part of The Eastern Belt Granite of Peninsular Malaysia consist mainly of I-type granites. Three weathered granite profiles from Kuantan, were sampled and analyzed for their mineralogy and rare earth elements (REEs) characteristics. The I-type parent granites of Kuantan consist of quartz (29- 35 %), K-feldspar (23-30 %), plagioclase (18-28%), biotite (10%), hornblende (5-8 %) and 0.6-1.4 % accessory minerals (zircon, apatite, monazite-(Ce) and chlorite) respectively. The granite weathering profiles have been divided into three main horizons with increasing depth above the parent granite: 1) saprock horizon (slightly weathered); 2) saprolite horizon (highly weathered) and 3) topsoil (completely weathered with rich organic matters). The concentrations of REEs in the weathering profiles considered to be economic for ion adsorption clay type deposits with rule of thumb >500 ppm in 1 g of sample. In order to produce an exploration model for REEs in Peninsula Malaysia, the formation process of the different weathering horizons was investigated, and the REEs concentrations has been identified. All the soil samples show prominent positive Ce anomalies with lower REEs contents (64 – 107 ppm). In contrast, the saprolite horizon is a leached zone characterized by a negative Ce anomaly and elevated REEs contents. The negative Ce anomaly and REEs enrichment in the saprolite layer indicates immobilization of REE3+ by adsorption and distribution into secondary REEs minerals with REEs distribution agent such as clay minerals. The ion-adsorption (leached) fraction was enriched in light rare earth elements (LREE) with accounted for 80–90 % of the total REE content in the investigated saprolite and saprock sample

Electrodialysis membrane with concentration polarization – A review

Electrodialysis (ED) is more robust than reverse osmosis in terms of scaling, purity, and control, but its efficiency is dependent on concentration polarization. Concentration polarization is not only inherent in ED, but also commonly found in microfiltration, ultrafiltration, nanofiltration, reverse osmosis, and fuel cells with ion exchange membranes (IEMs). The current meta-synthesis review aims to identify the best approach for reducing concentration polarization, increasing velocity, or maximizing spacer design. Concentration polarization can significantly impact membrane capability and reduce overall performance. To reduce concentration polarization, innovative geometries and configurations of membrane spacers are needed. Carefully designed spacers that increase channel turbulence can help mitigate concentration polarization effects. However, advanced spacers still have negative consequences, such as the shadow effect, which reduces the ion exchange area and increases permeation resistance. Increasing the flowrate can improve membrane performance, maximize recovery/permeate rate, and reduce the limitations of spacer design. However, increasing the flowrate can have drawbacks in certain membrane applications. For example, a higher Reynolds number may improve spacer performance with a higher Sherwood number but at the cost of a greater power number. This review found that the extent of concentration polarization formation is heavily influenced by both spacer design and solution velocity. Convective motions affect mixing, making the concentration domain within the cell highly dependent on spacer design and flow velocity

A review of wastewater bacterial bio oxidation: Mechanisms, reactions, and behaviors

The most overlooked biological process is the oxidation process, due to the poor technical understanding of bioremediation and the many unexplained biological mechanisms. As a matter of fact, wastewater companies favor the physical and chemical approaches over the biological means to ensure process performance. Biological oxidation provides environmentally friendly treatment with limited operational requirements. It has a tremendous ability to metabolize ammonia, H2S, phosphate, and ferrous iron under the right conditions. Bacterial communities attack these wastewater components through using oxygen as a strong electron acceptor, resulting in simplified forms of wastewater components (e.g., ammonia to nitrogen gas). This manuscript reviews in details the mechanisms of wastewater bacteria against various pollutants, with the possible reactions and behaviors. It also presents the benefits of utilizing wastewater microorganisms against different pollutants

Electrodialysis membrane desalination with diagonal membrane spacers: a review

Electrodialysis desalination uses ion exchange membranes, membrane spacers, and conductors to remove salt from water. Membrane spacers, made of polymeric strands, reduce concentration polarization. These spacers have properties such as porosity and filament shape that affect their performance. One important property is the spacer-bulk attack angle. This study systematically reviews the characteristics of a 45° attack angle of spacers and its effects on concentration polarization and fluid dynamics. Membrane spacers in a channel create distinct flow fields and concentration profiles. When set at a 45° attack angle, spacers provide greater turbulence and mass-heat transfer than traditional spacers. This is because both the transverse and longitudinal filaments become diagonal in relation to the bulk flow direction. A lower attack angle (<45°) results in a lower pressure drop coupled with a decline in wakes and stream disruption because when the filaments are more parallel to the primary fluid direction, the poorer their affect. This research concludes that membrane spacers with a 45° spacer-bulk attack angle function optimally compared to other angles

Electrodialysis desalination: The impact of solution flowrate (or Reynolds number) on fluid dynamics throughout membrane spacers

The incorporation of a spacer among membranes has a major influence on fluid dynamics and performance metrics. Spacers create feed channels and operate as turbulence promoters to increase mixing and reduce concentration/temperature polarization effects. However, spacer geometry remains unoptimized, and studies continue to investigate a wide range of commercial and custom-made spacer designs. The in-depth discussion of the present systematic review seeks to discover the influence of Reynolds number or solution flowrate on flow hydrodynamics throughout a spacer-filled channel. A fast-flowing solution sweeping one membrane's surface first, then the neighboring membrane's surface produces good mixing action, which does not happen commonly at laminar solution flowrates. A sufficient flowrate can suppress the polarization layer, which may normally require the utilization of a simple feed channel rather than complex spacer configurations. When a recirculation eddy occurs, it disrupts the continuous flow and effectively curves the linear fluid courses. The higher the flowrate, the better the membrane performance, the higher the critical flux (or recovery rate), and the lower the inherent limitations of spacer design, spacer shadow effect, poor channel hydrodynamics, and high concentration polarization. In fact, critical flow achieves an acceptable balance between improving flow dynamics and reducing the related trade-offs, such as pressure losses and the occurrence of concentration polarization throughout the cell. If the necessary technical flowrate is not used, the real concentration potential for transport is relatively limited at low velocities than would be predicted based on bulk concentrations. Electrodialysis stack therefore may suffer from the dissociation of water molecules. Next studies should consider that applying a higher flowrate results in greater process efficiency, increased mass transfer potential at the membrane interface, and reduced stack thermal and electrical resistance, where pressure drop should always be indicated as a consequence of the spacer and circumstances used, rather than a problem

Simulation solvent extraction of rare earth metal source origin from marine sediment

Ocean mining probably one of the world's largest untapped resources of rare earth elements. Specifically, the rare earth resources from polymetallic nodule which receive less attention from industry due to the various challenges. This article studied the simulation HDEHP-HCl system fractional cascade extraction strategy for extraction of rare earth elements from polymetallic nodule. HDEHP-HCl was capable of complete extract very high purity rare earth elements (99.9%). The fractional cascade extraction strategy simulation designed for the separation of rare earth elements could be momentous for practical application. The simulation data shows high purity of products at both outlets, aqueous and organic are obtainable. All these will provide the promising industrial applications of HDEHP-HCl system in extracting rare earth elements from polymetallic nodule with more fundamental data and guidance

Impact of membrane spacers on concentration polarization, flow profile, and fouling at ion exchange membranes of electrodialysis desalination: Diagonal net spacer vs. ladder-type configuration

The idea of electrodialysis was discovered 120 years ago, and its industrial development was initiated more than 50 years ago due to the introduction of ion exchange membranes (IEMs). Concentration polarization limits performance by generating a narrow diffusion boundary layer along IEMs with values greater than the membrane's resistance. To attain maximum stack hydrodynamics, membrane spacers can be used to minimize polarization near membrane sheets. Most notably, the filament array creates an attack angle (or inclination angle) with regard to the main flow direction at a reference direction of x. The present systematic review provides a brief overview of membrane spacers and bulk-spacer attack angles before introducing two forms of membrane spacers, diamond configuration and ladder-type configuration, with attack angles of 45° and 0°/90°, respectively, to the primary streamlines. The attack angle describes the orientation of the spacer filaments in reference to the major direction of solution flow. The study discovered that attack angles of 90° and 0° with respect to the primary flow direction in the x-coordinate circulate solution across filaments that intersect at a 90° angle without changing the y-flow direction. This is because the filaments of the 90° spacer are transverse with respect to flow direction, and the flow pattern at the membranes is predominantly dictated by the orientation of the spacer filaments; hence, the flow patterns created by the 0°, 45°, and 90° attack angles differ. An ineffective attack angle requires the use of prolonged, tortuous, and adequate routes in channel length to aid in providing a desirable rate of mixing with turbulences. There is an advantage to employing 45° since it always demands a lower Reynolds number value than 90°, resulting in better flow profiles and stronger turbulences. At any given normalized pumping power, the mixing quality of the diagonal net with a 45° attack angle produces more turbulence than a 0° or 90° attack angle, significantly disrupting the boundary layer, reducing the presence of poorly mixed zones, and resulting in a higher heat-mass transfer rate from the channel core to the membrane surfaces. It is because 45° has diagonal filaments, which results in the reversal of multidirectional velocity vectors, changing fluid direction, and a good hydrodynamic dispersion flux involving longitudinal, transverse, and diagonal dispersion coefficients as diagonal components along the velocity field direction. On the other hand, only longitudinal vortices and longitudinal reversal velocity vectors can be promoted by 0°/90° along the channel

A review of ion adsorption clay as a high potential source of rare earth minerals in Malaysia

Rare earth elements (REEs) have emerged as a critical component in manufacturing various products for green technology. This paper aims to comprehensively review the formation of ion adsorption clay, REEs weathering profile, clay minerals’ potential in adsorbing REEs, ion-exchange mechanism and method for REEs extraction, and the potential of ion adsorption clay as a REEs source in Malaysia. In conclusion, ion adsorption clay has significant potential as a REEs mineral source in Malaysia, where a higher concentration of REEs has been identified compared to China, a developing country in the REEs minerals industry of ion adsorption clay

Electrodialysis membrane desalination for water and wastewater processing: irregular attack angles of membranes spacers

Electrodialysis desalination is constructed with a number of anion exchange membranes (AEM), cation exchange membranes (CEM), anode, cathode, adjacent silicon gasket integrated membrane spacers, and inlet/outlet holes per cell. At the boundary among an ionic solution and an ion exchange membrane, concentration polarization develops. Spacers placed in between channel’s walls function as stream baffles to increase turbulence, improve heat and mass transfer, diminish the laminar boundary layer, and lessen fouling problems. The current study offers a systematic review of membrane spacers, spacer-bulk attack angles, and irregular attack angles. Spacer-bulk attack angle is accountable for variations in the pattern and direction of stream which impact heat-mass transfer and concentration polarization. Irregular attack angles (e.g., 0°, 15°, 30°, 37°, 45°, 55°, 60°, 62°, 70°, 74°, 80°, 90°, 110°, 120°) in the present study were found to provide unique stream patterns due to the spacer’s filaments being less or more transverse in respect to the primary solution direction, which may significantly alter heat transfer, mass transport, pressure drop, and overall flow dynamics. Spacer applies shear stress resulting by continuous stream tangent to the membrane exterior, which lessens polarization. In the end, 45° is concluded as the preferred attack angle that offers balanced rates of heat transfer, mass transport, and pressure drop throughout the feed channel while greatly lowering the rate of concentration polarization