Is the dewatering of Palm Oil Mill Effluent (POME) feasible? Effect of temperature on POME's rheological properties and compressive behavior

The current treatment process of Palm Oil Mill Effluent (POME) has been a cause of concern over recent years as POME is known to cause greenhouse gas emission as well as water pollution. An alternative for POME treatment process optimization is to eliminate the conventional cooling ponds and introduce a dewatering device such as a thickener. The thickener will assist in the solid-liquid separation, removal of microbes and other impurities from the wastewater. The latter will contribute to making the anaerobic digesters used to treat POME more efficient by allowing a means of control on the digesters’ load. However, to be able to design and predict the performance of the thickener unit; essential rheological properties of the suspension have to be determined. The rheological characteristics and the compressive behavior of POME have not been studied previously nor has the implementation of such a dewatering device in the POME treatment process. This paper attempts to bridge the gap on the rheological characteristics, the compressive behavior and the effect of temperature on the rheological properties of POME through batch settling and batch filtration experiments. Data such as the compressive yield stress, the hindered settling function, and the diffusivity function for POME have been extracted and evaluated

Instantaneous Segmental Energy Symmetry Index as Gait Compensation Indicator in Asymmetrical Walking

Purpose: Human body constantly adapts to optimise the energy expenditure. A better understanding of the mechanical energetic costs in lower extremities helps identify the compensatory mechanism adopted in asymmetrical gait. This paper proposes the use of instantaneous segmental energy and normalised symmetry index (SInorm) to examine asymmetrical gait. This approach can provide better overview of gait quality allowing identification of change in segmental energy during different gait phases and contribution of each segment in compensating abnormal walking. Method: An experimental study was carried out to validate this method. Twenty healthy subjects were recruited. Asymmetrical gait was simulated by restricting knee motion during walking using a knee brace. Mechanical energy was determined for each segment of the left and right limbs. Normalised Symmetry Index (SInorm) was then calculated to examine bilateral differences in segmental energy during stance phase and swing phase. Statistical analysis using ANOVA and Tukey-Kramer multiple comparison test to identify asymmetry of the segmental energy (p-value < 0.05). Result: Significant asymmetry of segmental energy occurred during swing phase. Greater asymmetry was observed in kinetic energy than in potential energy. The affected limb segments produced lower kinetic energy than the normal limb. At asymmetrical state, potential energy of the affected limb’s foot and thigh were lower than that of the normal segments while the inverse was true for thigh segment. Conclusion: These results suggested that in asymmetrical gait, a form of compensatory mechanism is adopted to walk. This can be observed in the change of instantaneous segmental energy during walking

Real-time wireless ambulatory gait monitoring system incorporating online periodical gait evaluations

Human gait analysis studies the coordination of human lower extremity in providing propulsion to move forward while maintaining the body balance, with one foot in contact with the ground at all time. Hence, gait analysis plays an important role in clinical settings and rehabilitations. It is widely performed to identify various gait disorders, to assess the functional performance of a patient’s lower limb before and after a surgery or medical treatment, and to evaluate patient’s rehabilitation progress. In engineering, its importance is reflected in the design and development of the prosthetic limb, Functional Electrical Stimulation (FES) system as well as the humanoid robot. Optical motion capture system and force platform are commonly used in gait analysis to quantify human motion. However, these systems are expensive, bulky and can only capture human motion in a dedicated environment i.e. laboratory. As an alternative, this thesis developed a real-time gait monitoring system that utilizes wireless miniature gyroscopes. The miniature gyroscope is small, light-weight, and can capture human motion in both indoor and outdoor environments. More importantly, it is equipped with wireless data transmission, which offers additional benefits. Wireless gyroscope provides relatively larger movement area. It also does not obstruct the natural motion of human lower extremity. Apart from the advantages offered by the wireless gyroscopes, this system also uses several novel methods to assist clinicians and researchers in identifying abnormal gait. These methods evaluate three main aspects of human gait. They are referred as the gait normality test, gait asymmetry analysis, and the estimation of gait dynamic stability. Gait normality test examines a person’s gait relative to normal/healthy individual’s gait that was established by other researchers. Gait asymmetry analysis is an evaluation that examines the bilateral differences between the left and right limbs.The estimation of gait dynamic stability determines human walking stability using nonlinear time series analysis. It uses short-term and long-term maximum Lyapunov exponent to quantify the ability of human neuromuscular locomotor system in maintaining body balance during walking. Experimental study was also conducted to examine the overall capability of this system. This study simulated the abnormal gait by placing a load on one side of the limbs and by wearing a sandal on one foot. These methods successfully altered the inertial property of a person’s lower limb, hence inducing significant differences in spatio-temporal gait parameters between the affected limb and the non-affected limb. As expected, the experimental results were satisfactory. Significant differences between normal and abnormal gait were observed with p < 0.01. These results validated the use of these methods to simulate abnormal gait on a healthy individual. They also demonstrated the viability of this system for future clinical applications

Real-time wireless ambulatory gait monitoring system incorporating online periodical gait evaluations

Human gait analysis studies the coordination of human lower extremity in providing propulsion to move forward while maintaining the body balance, with one foot in contact with the ground at all time. Hence, gait analysis plays an important role in clinical settings and rehabilitations. It is widely performed to identify various gait disorders, to assess the functional performance of a patient’s lower limb before and after a surgery or medical treatment, and to evaluate patient’s rehabilitation progress. In engineering, its importance is reflected in the design and development of the prosthetic limb, Functional Electrical Stimulation (FES) system as well as the humanoid robot. Optical motion capture system and force platform are commonly used in gait analysis to quantify human motion. However, these systems are expensive, bulky and can only capture human motion in a dedicated environment i.e. laboratory. As an alternative, this thesis developed a real-time gait monitoring system that utilizes wireless miniature gyroscopes. The miniature gyroscope is small, light-weight, and can capture human motion in both indoor and outdoor environments. More importantly, it is equipped with wireless data transmission, which offers additional benefits. Wireless gyroscope provides relatively larger movement area. It also does not obstruct the natural motion of human lower extremity. Apart from the advantages offered by the wireless gyroscopes, this system also uses several novel methods to assist clinicians and researchers in identifying abnormal gait. These methods evaluate three main aspects of human gait. They are referred as the gait normality test, gait asymmetry analysis, and the estimation of gait dynamic stability. Gait normality test examines a person’s gait relative to normal/healthy individual’s gait that was established by other researchers. Gait asymmetry analysis is an evaluation that examines the bilateral differences between the left and right limbs.The estimation of gait dynamic stability determines human walking stability using nonlinear time series analysis. It uses short-term and long-term maximum Lyapunov exponent to quantify the ability of human neuromuscular locomotor system in maintaining body balance during walking. Experimental study was also conducted to examine the overall capability of this system. This study simulated the abnormal gait by placing a load on one side of the limbs and by wearing a sandal on one foot. These methods successfully altered the inertial property of a person’s lower limb, hence inducing significant differences in spatio-temporal gait parameters between the affected limb and the non-affected limb. As expected, the experimental results were satisfactory. Significant differences between normal and abnormal gait were observed with p < 0.01. These results validated the use of these methods to simulate abnormal gait on a healthy individual. They also demonstrated the viability of this system for future clinical applications

The impact of thermal pretreatment on various solid-liquid ratios of palm oil mill effluent (POME) for enhanced thermophilic anaerobic digestion performance

An advancement to the treatment process of palm oil mill effluent (POME) was proposed whereby a pretreatment technology and a dewatering device are introduced into the existing treatment process. Thermal pretreatment is a robust technique with the ability to enhance the rate and increase the biogas production of anaerobic digestion. The dewatering device will confer a means of control on the digester's load, allowing the removal of microbes and impurities as well as assist in the residual oil removal. The proposed advancement to the treatment process allows the removal of cooling ponds making the treatment process more sustainable in terms of the substantial reduction in the amount of greenhouse gas emission, improved residual oil removal efficiency in the waste stream, and better treated effluent quality. However, to be able to implement this innovative treatment method effectively, it is fundamental to know how thermal pretreatment undertook on the solid content of POME impacts on the anaerobic digestion process performance. To conduct the study mentioned above, POME was pretreated at 120°C and was allowed to settle to separate the settled suspension and the clear liquor phases (hereafter denoted “solid” as S and “liquid” as L). Batch thermophilic anaerobic digestion was conducted on various solid: liquid ratios (i.e., the 20S:80L, 40S:60L, 50S:50L, 75S:25L, and 100S). It was found that the optimal ratios were 20S:80L and 40S:60L, which generated approximately 9-fold and 6-fold higher methane yield, respectively, in contrast to their untreated counterparts. Thermally pretreated 40S:60L solid loading exhibited a higher removal efficiency in terms of chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solids (TSS), and oil & grease (O&G), a higher methane yield of 328 mL CH4/g CODremoved and biogas production of 1886±21 mL from a working volume of 100 mL compared to all the other pretreated and untreated ratios

Applicability of various pretreatment techniques to enhance the anaerobic digestion of Palm Oil Mill Effluent (POME) : a review

Palm Oil Mill Effluent (POME) is a potential source of renewable energy. With the intensified energy demands in various industries, if the biogas production from POME treatment can be sustained, the palm oil industry can be made more environmentally and economically sustainable. The current POME treatment process is ineffective in removing residual oil and creates a large amount of greenhouse gas emissions. Furthermore, the limitation of the treatment process is the instability of the anaerobic digestion stage, which is affected by various operating parameters. Subsequently, the chemical and physical characteristics of POME vary depending on different factors, such as the harvest season and the efficiency of the palm oil extraction process. Therefore, having an effective pretreatment system can radically reduce the load on the anaerobic digesters, sustain biogas production, and enhance the treated effluent quality so that it can conform to the stringent environmental standards. The focus of this paper is to review the pretreatment methods (treatments undertaken prior to anaerobic digestion, which contributes to enhancing the hydrolysis step). A comparison of various types of sludge will be carried out to allow a thorough understanding of the impacts of these pretreatment methods and the suitability of their implementation for POME treatment. It was established that thermal pretreatment has bene proven to enhance solubilization, biogas production and the quality of the treated effluent. The increase in biogas production can easily compensate for the energy added to the system

Parkinson’s disease diagnosis and severity assessment using ground reaction forces and neural networks

Gait analysis plays a key role in the diagnosis of Parkinson’s Disease (PD), as patients generally exhibit abnormal gait patterns compared to healthy controls. Current diagnosis and severity assessment procedures entail manual visual examinations of motor tasks, speech, and handwriting, among numerous other tests, which can vary between clinicians based on their expertise and visual observation of gait tasks. Automating gait differentiation procedure can serve as a useful tool in early diagnosis and severity assessment of PD and limits the data collection to solely walking gait. In this research, a holistic, non-intrusive method is proposed to diagnose and assess PD severity in its early and moderate stages by using only Vertical Ground Reaction Force (VGRF). From the VGRF data, gait features are extracted and selected to use as training features for the Artificial Neural Network (ANN) model to diagnose PD using cross validation. If the diagnosis is positive, another ANN model will predict their Hoehn and Yahr (H&Y) score to assess their PD severity using the same VGRF data. PD Diagnosis is achieved with a high accuracy of 97.4% using simple network architecture. Additionally, the results indicate a better performance compared to other complex machine learning models that have been researched previously. Severity Assessment is also performed on the H&Y scale with 87.1% accuracy. The results of this study show that it is plausible to use only VGRF data in diagnosing and assessing early stage Parkinson’s Disease, helping patients manage the symptoms earlier and giving them a better quality of life

Moving toward Soft Robotics: A Decade Review of the Design of Hand Exoskeletons

Soft robotics is a branch of robotics that deals with mechatronics and electromechanical systems primarily made of soft materials. This paper presents a summary of a chronicle study of various soft robotic hand exoskeletons, with different electroencephalography (EEG)- and electromyography (EMG)-based instrumentations and controls, for rehabilitation and assistance in activities of daily living. A total of 45 soft robotic hand exoskeletons are reviewed. The study follows two methodological frameworks: a systematic review and a chronological review of the exoskeletons. The first approach summarizes the designs of different soft robotic hand exoskeletons based on their mechanical, electrical and functional attributes, including the degree of freedom, number of fingers, force transmission, actuation mode and control strategy. The second approach discusses the technological trend of soft robotic hand exoskeletons in the past decade. The timeline analysis demonstrates the transformation of the exoskeletons from rigid ferrous materials to soft elastomeric materials. It uncovers recent research, development and integration of their mechanical and electrical components. It also approximates the future of the soft robotic hand exoskeletons and some of their crucial design attributes

The influence of different solid-liquid ratios on the thermophilic anaerobic digestion performance of palm oil mill effluent (POME)

An alternative method was proposed to optimize the treatment process of palm oil mill effluent (POME) in an effort to address the poor removal efficiencies in terms of the chemical and biological oxygen demand (COD and BOD), total suspended solids (TSS) as well as oil and grease (O&G) content in treated POME along with many environmental issues associated with the existing POME treatment process. The elimination of the cooling ponds and the insertion of a dewatering device in the treatment process were recommended. The dewatering device should enhance the anaerobic digestion process by conferring a means of control on the digesters’ load. The objective of this study is to identify the optimum solid: liquid ratio (total solids (TS) content) that would generate the maximum amount of biogas with better methane purity consistently throughout the anaerobic digestion of POME, all while improving the treated effluent quality. It was established that a 40S:60L (4.02% TS) was the best performing solid loading in terms of biogas production and methane yield as well as COD, BOD, TSS, and O&G removal efficiencies. Meanwhile, at higher solid loadings, the biogas production is inhibited due to poor transport and mass transfer. It is also speculated that sulfate-reducing bacteria tended to inhibit the biogas production based on the significantly elevated H2S concentration recorded for the 75S:25L and the 100S loadings

Muscles affecting minimum toe clearance

The aim of this study was to investigate how the anterior and posterior muscles in the shank (Tibialis Anterior, Gastrocnemius Lateralis and Medialis), influence the level of minimum toe clearance (MTC). With aging, MTC deteriorates thus, greatly increasing the probability of falling or tripping. This could result in injury or even death. For this study, muscle activity retention taping (MART) was used on young adults, which is an accepted method of simulating a poor MTC—found in elderly gait. The subject's muscle activation was measured using surface electromyography (SEMG), and the kinematic parameters (MTC, knee and ankle joint angles) were measured using an optical motion capture system. Our results indicate that MART produces significant reductions in MTC (P < α), knee flexion (P < α) and ankle dorsiflexion (P < α), as expected. However, the muscle activity increased significantly, contrary to the expected result (elderly individuals should have lower muscle activity). This was due to the subject's muscle conditions (healthy and strong), hence the muscles worked harder to counteract the external restriction. Yet, the significant change in muscle activity (due to MART) proves that the shank muscles do play an important role in determining the level of MTC. The Tibialis Anterior had the highest overall muscle activation, making it the primary muscle active during the swing phase. With aging, the shank muscles (specifically the Tibialis Anterior) would weaken and stiffen, coupled with a reduced joint range of motion. Thus, ankle-drop would increase—leading to a reduction in MTC