Biofuel Production from Waste Cooking Oils and its Physicochemical Properties in Comparison to Petrodiesel

Haphazard mining and consumption of fossil fuels have reduced petroleum reserves causing fossil fuel depletion and environmental degradation; thus, reflecting the need for the cheaper, renewable and eco-friendly alternative source of petroleum to meet the fuel demand. A million liters of edible oil used for cooking foods and date expired oils from oil manufacturers are discarded into sewage. This study primarily intends to study the feasibility of biodiesel production using such waste oils. In this work, biodiesel was prepared from waste cooking oils by a process called transesterification with NaOH as a catalyst. Our results showed that methyl ester (biodiesel) (92.67±0.90%), soap materials (1.33±0.224%), and glycerol (6±0.68%) were obtained after the transesterification of waste cooking oil. The physicochemical properties of biodiesel such as density, viscosity, volatility, surface tension, and flashpoint were analyzed, which were found to be 0.862±0.006 g/cm3, 2.23±0.021 cP, 0.327×10-3±4.5×10-6 g/s, 32.03±0.138 dyne/cm, 169.67±0.810°C, respectively. These properties were compared with that of commercial diesel as well as with the values specified by the American Society for Testing and Materials (ASTM) D6751. The density and the surface tension of the biodiesel were found similar to that of petrodiesel but its volatility was 3 times lower. Fourier-transform infrared spectroscopy (FTIR) spectra of the biodiesel showed methyl ester functional group at 1436 cm-1. Based on the cost of the materials used for production, the cost of biodiesel was estimated to be about 81 Nepalese rupees (0.67 USD) per liter. The properties of biodiesel also met the standard values of ASTM D6751. These findings indicate that waste oil is one of the feasible biodiesel sources and it can be used as a suitable alternative to petrodiesel

Traditional, video and extended reality (XR) assisted flipped classroom teaching methods:an approach and comparison

This paper examines the comparative effectiveness of three distinct Flipped Classroom (FC) teaching methods in the context of Power and Electrical (PE) engineering education: Traditional Flipped Classroom (TFC), Video-Assisted Teaching Methods (VAFC), and Virtual Reality Flipped Classroom (VRFC). The study incorporates valuable feedback from students who experienced these methods and provides an evaluation of their perceptions. A cross-over methodology for comparing these FC methods is presented. The VAFC method is perceived to be an effective approach and preferred over TFC and VRFC by students. The paper also provides Teachers' perception in implementing above FC methods, which outlines a process for developing VAFC and VRFC teaching resources. Operational difficulties in implementing such methods are highlighted, especially in the context of fast-paced, privately-catered undergraduate education sector striving for implementing non-conventional teaching methods

Procurement process and shortages of essential medicines in public health facilities: A qualitative study from Nepal

Ensuring access to essential medicines remains a formidable challenge in Nepal. The specific reasons for the shortage of essential medicines within Nepal have not been extensively investigated. This study addresses challenges associated with access to essential medicines, procurement process difficulties, and functionality of inventory management systems at different levels of public health facilities. Fifty-nine semi-structured in-depth interviews were conducted with health managers and service providers at provincial and local levels in six randomly selected districts of Bagmati province, Nepal. Interviews were audiotaped and transcribed verbatim, and the results were analyzed using the inductive approach and were later mapped within the four domains of “Procurement of essential medicines”. The major barriers for the effective management of essential medicines included delays in the procurement process, primarily locally, leading to frequent stock-out of essential drugs, particularly at the health post level. Additionally, challenges arise from storage problems, mainly due to insufficient storage space and the need to manage additional comorbidities related to COVID-19. Other identified challenges encompass the absence of training on logistics management information systems, a lack of information technology resources in primary health facilities, inadequate qualified human resources to operate the IT system, and insufficient power backup. Moreover, unrealistic demand estimation from the service points, inadequate transportation costs, and manual inventory management systems further contributed to the complex landscape of challenges. This study identified procurement delays as the primary cause of essential medicine shortages in Bagmati Province, Nepal. We recommend implementing comprehensive procurement guidelines, collaborative training, and dedicated budgets to address this issue. Improving the procurement and inventory management process in low-resource settings requires a well-trained workforce, suitable storage spaces, and enhanced coordinated administrative tiers within health facilities at different levels to ensure the year-round availability of essential medicines in these settings

Simple guidelines to minimise exposure to earthquake-triggered landslides

Reducing landslide risk in many mountainous regions is most effectively achieved by reducing exposure to landslides, because landslides cannot be predicted or stopped and engineering solutions are generally impractical or impossible. Because landslide hazard is very site-specific, available hazard maps may not be detailed enough, or contain appropriate and up-to- date information, to inform decision-making. We use our experience of studying the characteristics of landslides in recent large earthquakes to describe three simple guidelines that can be used to minimise exposure to future earthquake-triggered landslide hazard. The most effective measure is to choose a location that minimises the angle to the skyline, and to keep that angle below 25° if at all possible. It is also important to avoid steep channels (those with slopes of >15°), especially if there are many steep hillsides upstream. Finally, the slope of the ground at your location should always be minimised. These guidelines do not specify where landslides will occur, but can be used to distinguish between areas which are more or less likely to be affected by landslides in a large earthquake. They can be used to reduce risk before an earthquake occurs by helping to inform decisions on where to situate key infrastructure, such as schools or health posts. They can be used to inform decisions about the locations of houses, markets, or other areas where people are likely to spend considerable periods of time, or for deciding on appropriate types of land use. The guidelines can also be used in disaster preparedness and response planning, by identifying suitable evacuation routes and open spaces for use as evacuation sites or emergency shelters. We provide some brief guidance on what to do immediately after an earthquake in order to minimise exposure to landslides, and discuss the relevance of these guidelines for protecting against rainfall-triggered landslides which may occur more frequently

Molecular Docking and ADMET Prediction of Compounds from Piper longum L. Detected by GC-MS Analysis in Diabetes Management

Medicinal plants have been utilized traditionally for therapeutics against various diseases. This study focuses on identifying bioactive compounds present in the fruit of hexane, ethyl acetate, and methanol extract of Piper longum L. through GC-MS analysis. The molecular level computational exploration of its phytocompounds against diabetes through molecular docking and ADMET prediction was carried out. The results of the GC-MS analysis unveiled the presence of 33 different phytochemicals and the Molecular docking revealed that 5,6-dihydroergosterol, β-sitosterol, and piperine demonstrated better binding affinities of -9.7 kcal/mol, -9.5 kcal/mol, and -7.9 kcal/mol, respectively with α-amylase (PDB ID: 2QV4) and -9.1 kcal/mol, -9.4 kcal/mol and -8.1 kcal/mol respectively with α-glucosidase (PDB ID: 5ZCC). Most of the docked compounds exhibited significant binding with the receptor protein greater than that of the reference drugs (miglitol, voglibose, and metformin). Moreover, the ADMET predictions suggested that the compounds were comparative with the reference drugs. These phytochemicals may be considered promising candidates for addressing diabetes by interfering with the normal functioning of α-amylase and α-glucosidase. The study recommends additional in vitro and in vivo experiments to validate the preliminary in silico results

Procurement process and shortages of essential medicines in public health facilities: A qualitative study from Nepal

Ensuring access to essential medicines remains a formidable challenge in Nepal. The specific reasons for the shortage of essential medicines within Nepal have not been extensively investigated. This study addresses challenges associated with access to essential medicines, procurement process difficulties, and functionality of inventory management systems at different levels of public health facilities. Fifty-nine semi-structured in-depth interviews were conducted with health managers and service providers at provincial and local levels in six randomly selected districts of Bagmati province, Nepal. Interviews were audiotaped and transcribed verbatim, and the results were analyzed using the inductive approach and were later mapped within the four domains of “Procurement of essential medicines”. The major barriers for the effective management of essential medicines included delays in the procurement process, primarily locally, leading to frequent stock-out of essential drugs, particularly at the health post level. Additionally, challenges arise from storage problems, mainly due to insufficient storage space and the need to manage additional comorbidities related to COVID-19. Other identified challenges encompass the absence of training on logistics management information systems, a lack of information technology resources in primary health facilities, inadequate qualified human resources to operate the IT system, and insufficient power backup. Moreover, unrealistic demand estimation from the service points, inadequate transportation costs, and manual inventory management systems further contributed to the complex landscape of challenges. This study identified procurement delays as the primary cause of essential medicine shortages in Bagmati Province, Nepal. We recommend implementing comprehensive procurement guidelines, collaborative training, and dedicated budgets to address this issue. Improving the procurement and inventory management process in low-resource settings requires a well-trained workforce, suitable storage spaces, and enhanced coordinated administrative tiers within health facilities at different levels to ensure the year-round availability of essential medicines in these settings

Control and operation of DC microgrids

The utilization of DC microgrids in power industry has increased rapidly with the expansion in use of renewable energy sources (RES), energy storages and DC inherent loads. DC microgrid reduces the power conversion stages, does not require frequency, phase and reactive power control in its operation making it advantageous over AC microgrids. However, the cost-effective solution to renewable intermittency, system topology and standards for reliable, stable and efficient power supply still needs examinations through research. Control strategies, for economic solution to mitigate renewable intermittency in the system with inclusion of hybrid energy storage system (HESS), interconnection of microgrids with tie-line for reliable power supply and bipolar-type DC microgrids for high quality and high efficiency power supply, is proposed, implemented and elaborated in this thesis. Energy storages are an option to solve renewable intermittency that can increase the utilization of RES into grid, changing the undispatchable generation to dispatchable. Energy storages can generate profit upon charging them when local electricity price lowers and can be discharged when the price is high. Choice of energy storage ranging from short term to long term is a key factor to address the compensation of load peaks, transients and to provide autonomy to the microgrids. Unfortunately, they cannot be achieved by a single energy storage, thus the need of hybridization of energy storages that have high specific energy and specific power is the solution for proper compensation of power fluctuation in autonomous microgrids. Upon review, it was also found that combination of lead-acid battery and supercapacitor compensate the gap of high energy density and high power density respectively and proved to be the best solution for hybrid energy storage applications and hence used as HESS in this research. The conventional droop based decentralized control achieves static power regulation however, lacks to address frequency based autonomous power management for dynamic power control. Hence, a frequency coordinating virtual impedance concept has been explored in this thesis for the co-ordination control of an HESS in DC microgrids. It investigates power decoupling methods to better attenuate the ripple power by filtration. This research uses lead-acid battery and supercapacitor to form HESS and are connected to a common DC bus through bi-directional DC-DC converters. Battery converter can absorb low frequency power variations while supercapacitor converter can absorb the high frequency power variations. Battery supplies the long-term power demand and supercapacitor responds to the short-term power fluctuations during transient process in this control approach. For the reduction of ripple power in battery, insertion of high order low pass filter for battery and high order high pass filter for supercapacitor converters instead of lower order low/high pass filters have been proposed. The effectiveness of the proposed concept is shown through simulation and experimental results. The interconnection of DC microgrids for providing reliable power supply is particularly important in rural areas where utility grid is not available. Although, various researches are conducted in single entity, the interconnection of DC microgrid cluster is still novice in research. The interconnection of identical DC buses through tie-line and formation of microgrid clusters improves reliability of the system. To achieve power flow control through the tie- line, decentralized control approach has been proposed where the bus voltage of each microgrid in the microgrid cluster is controlled to ensure the regulation of bus voltage deviations. The use of decentralized control approach mitigates the issue of communication stress when the microgrid control areas are geographically distantly located. The decentralized control is accompanied by mode change based operation so that the distributed units like solar photovoltaic (PV) and energy storage system (ESS) in microgrids can adaptively adjust their operation modes depending upon the designated voltage level. By doing so, the bus voltage regulation (BVR) and power flow control is adjusted making each microgrid in the microgrid cluster autonomous. The power is generated/injected from/into microgrid when there is power surplus/deficit caused by supply-demand mismatch in particular microgrid. Tie-line power flow takes place in a microgrid, from another microgrid, due to the bus voltage decrement beyond the designated level caused by the increment in local consumption which could not be satisfied by the local generation and storages. The effectiveness of proposed decentralized control has been verified experimentally in the cluster of two microgrids. Recently, bipolar-type DC microgrids have gained tremendous attention of researchers due to its advantages over conventional DC microgrids in terms of elevated level of quality, reliability and efficient power supply. Due to different loading in upper and lower terminals, voltage fluctuation from nominal value at respective terminals takes place and makes the system unbalanced. So, the control of parallel converters which interface distributed energy resources (DERs) and the topology of the converter along with voltage balancer play vital role in formation of efficient bipolar-type DC microgrid. The bipolar configuration of converters in a DC microgrid can be formed by utilizing a converter to boost the input voltage and adopting a three-wire system by the means of voltage balancing circuit. Although many control schemes have been proposed for bipolar-type DC microgrids, they mainly focus on coupled microgrids with a centralized voltage balancer. The centralized voltage balancing technique is prone to deteriorate the system functionality due to the failure in communication links. Replacement of a centralized proportional-integral controller with multiple decentralized voltage balancers in a microgrid enhances the system reliability by removal of the communication links. This thesis proposes a decentralized control for bipolar-type DC microgrids with a decentralized voltage balancing scheme for two battery energy storages. Droop control is implemented in this thesis for boost converters and voltage balancing circuits to realize decentralized power management for both load sharing and voltage balancing. The simulation results and experimental validations are provided to present the problem and associated solutions. The proposed control strategies for operation of DC microgrid incorporating rooftop PV and HESS, interconnection of two DC microgrids consisting of PV and energy storages and bipolar-type DC microgrid consisting of two energy storages have been verified with Piecewise linear electrical circuit simulation (PLECS) software. Experimental cases have been carried out to validate the simulation studies with laboratory scale DC microgrid(s) prototype(s) developed at Water and Energy Research Laboratory (WERL), School of Electrical and Electronic Engineering, Nanyang Technological University.Doctor of Philosophy (EEE

Development of a Regional Geodatabase and 3D Models of Metro Vancouver and Their Use and Impact to Regional Seismic Hazard Mapping

Metro Vancouver faces a significant earthquake hazard due to its proximity to the Cascadia subduction zone. As Metro Vancouver has a high population density, the region\u27s heterogeneous geology which includes uneven, glacially eroded bedrock overlain by thick Quaternary deposits contributes significantly to the heightened seismic risk. Geodata plays an essential role in seismic microzonation mapping. A comprehensive geodatabase specific to western Metro Vancouver is developed from open-source and proprietary sources in combination with field geodata collection to achieve regional seismic microzonation mapping. This geodatabase enabled development of an empirical relationship between standard penetration resistance and shear-wave velocity of Holocene post-glacial sediments, and 3D seismic geology and shear-wave velocity models of Metro Vancouver. The potential impact of a comprehensive regional database of seismic site conditions within Metro Vancouver to seismic hazard assessment is examined in terms of reducing seismic design ground motions of the 2020 National Building Code of Canada based on in situ shear-wave velocity measurements of the top 30 meters. We explore the variability in key seismic site characterization measures most often used for seismic microzonation mapping to evaluate the impact on mapping and communication of seismic microzonation of Metro Vancouver. We find that the seismic microzonation of Metro Vancouver depends on the chosen seismic site parameter and that classification schemes with greater class divisions are beneficial to communicating the great variability in seismic site conditions in Metro Vancouver

An account of Nepal disasters and economic fallout

Nepal has remained a disaster-prone country with major disasters occurring at various intervals. There has not been sufficient research on Nepal disasters regarding the degree of loss, effects on the economy and post-disaster responses and its effects on economic revival. This paper was primarily set to analyze economic effect of natural disasters from 1971 to 2017 but for the lack of complete data on loss value for all the events an attempt was made to make a proper estimate for all the events; and the economic loss ensuing from the disasters has been assessed as a proportion of gross domestic product, and further to its impact on the year to year growth of the economy. The paper adds to the finding of other studies that disaster lends negative effect and that too is more prominent in the event of major disasters and more pronounced when coupled with political disruptions

Decentralized control of two DC microgrids interconnected with tie-line

Abstract This paper examines the interconnection of two DC microgrids (MGs) with tie-line. The voltages at respective MG buses are controlled to manage the power flow across the tie-line. Formation of such a DC MG cluster ensures higher reliability of power supply and flexibility to manage distributed energy resources and loads in the system. Two MGs consist of photovoltaic and battery units interfaced by power electronic converters. The bus voltages of two DC MGs act as an indicator for the power flow monitoring the supply-demand balance. A decentralized control approach is proposed to control each MG and bus voltage fluctuation in an allowable range. Furthermore, a mode adaptive decentralized control approach is proposed for seamless mode transition in order to assign microgrid operation modes and for the power management of DC MGs. The effectiveness of the proposed concept is validated by simulation and experimental results