Compression Techniques of Electrical Energy Data for Load Monitoring: A Review

In recent years, the electric grid has experienced increasing deployment, use, and integration of smart meters and energy monitors. These devices transmit big time-series load data representing consumed electrical energy for load monitoring. However, load monitoring presents reactive issues concerning efficient processing, transmission, and storage. To promote improved efficiency and sustainability of the smart grid, one approach to manage this challenge is applying data-compression techniques. The subject of compressing electrical energy data (EED) has received quite an active interest in the past decade to date. However, a quick grasp of the range of appropriate compression techniques remains somewhat a bottleneck to researchers and developers starting in this domain. In this context, this paper reviews the compression techniques and methods (lossy and lossless) adopted for load monitoring. Selected top-performing compression techniques metrics were discussed, such as compression efficiency, low reconstruction error, and encoding-decoding speed. Additionally reviewed is the relation between electrical energy, data, and sound compression. This review will motivate further interest in developing standard codecs for the compression of electrical energy data that matches that of other domains.

Finite Element Simulation of a Taylor Bubble in Two-Phase Gas-Liquid Slug Flows using Petrov-Galerkin Formulation

Petrov-Galerkin finite element scheme for systematic analysis of the dynamics of a rising Taylor bubble and general free surface flow problems is derived and implemented. The validity of the scheme is confirmed by simulating the buoyancy-driven motion of a Taylor bubble through a stagnant Newtonian liquid in a vertical pipe characterised by dimensionless inverse viscosity number and Eötvös number of magnitude 111 and 189, respectively. Comparison of the numerical results for the steady state features defining the nose, film, and bottom regions around the bubble with the experiment shows a good agreement between the numerical simulation and the experiment. The percentage deviation of the numerical computed rise velocity, equilibrium film thickness, and stabilisation length ahead of the bubble from the experimental determined values are 8.4%, 2.3%, and 9.5%, respectively.

Strength Characteristics of M40 Grade Concrete using Waste PET as Replacement for Sand

The wide variety of industrial and domestic applications of plastic products has fuelled a global trend in their use. The vast amount of plastic items that are discarded after use, on the other hand, pollutes the environment. In light of this, the current study investigated the use of Polyethylene Terephthalate (PET) as substitute for natural sand in concrete production. Locally sourced river sand was replaced with industrially ground waste PET in proportions of 4 to 20% at a step of 4% by the weight of natural sand whereas other concrete constituents (cement, granite, water-cement ratio and superplasticizer) were kept constant. A Grade M40 concrete with a mix proportion of 1:1:2:0.35 (cement: sand: granite: water-to-cement ratio) was used for all concrete mixes. Concrete without PET represents the control. Fresh (Slump) and hardened (compressive, split tensile and flexural) properties of the produced concrete were assessed using standard testing methods. The results showed that the slump of concrete decreased by 1.8% and 12.5% with an increase in PET content from 0 to 20%. The 28-day compressive strength of concrete containing PET was lower than the control. However, concrete with 4% PET compared considerably well with control with the compressive strength value exceeding the target strength of 40 N/mm2 while concretes containing PET beyond 4% had compressive strength below the target strength. The split tensile strength of concrete containing 4% PET was higher than that of the control but exhibited lower flexural strength than the control at the age of 28 days. It was concluded that the reuse of PET as a substitute for natural sand as an alternative waste disposal solution for eco-friendly concrete development and attainment of a pollution-free environment is viable.

Bathymetry Study of the Siltation Level of Lugu Dam Reservoir in Sokoto State, Nigeria

This paper seeks to determine the siltation level of the Lugu dam reservoir, Sokoto State, Nigeria, using the bathymetric survey method. A total of eleven (11) ground control points were established over the study area using Hi-Target Global Navigation Satellite (GNS) Real-time Kinematic (RTK) System. The base station was set- up over the reference Bench Mark while the Rover station was moved around to predetermine locations of the ground control points. The depths to the Lugu dam reservoir bed, as well as its underwater topographic mapping with a section of the River Rima on the right flank of the reservoir area, across the collapsed spillway were conducted using Garmin Global Positioning System Map. This was mounted on a nine feet fibre boat to enhance the echo sounding. The result of the study was used to produce a digital elevation model, topographic contours and the area-elevation-capacity curve for the reservoir. This indicates that between elevations 260.5 m and 262 m, the available minimum and maximum designed storage capacities of Lugu dam reservoir ranges from 21.24 MCM and 34.25 MCM respectively. The Lugu dam reservoir maximum storage capacity at breached level stands at 25 MCM, while its active storage capacity is 20 MCM. This is to conclude that the amount of siltation at the reservoir is 9.25 MCM representing 27.01% indicating the difference between the maximum designed capacity and the current storage capacity. It is recommended that dredging be carried out to regain the initial designed storage capacity as this will no doubt put an end to the incessant flooding and erosion experienced in the area.

Fuzzy Logic-based Data Controlled Wireless Sensor Network Routing Protocol for Flood Early Warning

Floods account for 15% of all natural disasters related deaths. Therefore, early flood warning systems using wireless network of sensors installed in flood prone areas is necessary to provide early notice of impending flood. This research focuses on the use of an energy efficient routing protocol to prolong the life time of the Network. The importance of this is to minimize energy consumption as necessary for reliable field operations. It adopts the use of mandami Fuzzy logic-based data controlled routing protocol (F-DCRP).Simulation was carried out for the F-DCRP, LEACH and Crisp Data controlled routing protocol (DCRP). The performance of the three protocols were obtained and compared. The result showed that Cluster head (CH) load was better shared uniformly among all the nodes. Percentage of packets dropped showed that the proposed F-DCRP was 10% lower compared to DCRP and 50% lower compared to LEACH resulting in more packets sent per round and greater reliability compared to LEACH and DCRP. The network lifetime was also improved by 40 % when compared to LEACH and DCRP.

Impact of Magnetically Treated Water on Compressive and Flexural Strength of Concrete

This study was conducted to determine the effect of Magnetically Treated Water (MTW) on compressive, flexural and impact strengths of concrete. The compressive strength, flexural and impact test were determined using 100 mm cube, 100x100x500 mm, 100mm diameter and 64 mm high, respectively. MTW was produced by passing water through magnetic flux densities: 400(T1), 600(T2), 800(T3) and 997G(T4) as the treatments while Non-MTW (NMTW, T0 as control). The ratio of cement, fine aggregate and coarse aggregate was 1:2:4 and curing duration for the concretes were 7, 14, 21 and 28 days. Universal Testing Machine was used to determine the compressive and flexural strengths while drop weighing impact tester was used for determining the impact strength of the concrete. The mean forces at peak to break the concrete cured for 28 days for T0, T1, T2, T3 and T4 were 106.79, 121.25, 114.15, 107.06 and 196.68 kN, while the compressive strengths were 10.68, 12.13, 11.42, 10.71 and 19.67 Nmm-2, respectively. The maximum compressive, flexural and impact strengths of the concrete were 84.17, 22.37 and 96.93%, respectively. The effect of MTW was statistically significant on compressive, flexural and impact strengths and is recommended for use.

Renewable Energy Resources Hybridization as an Efficient and Cost-Effective Alternative for Electrification

Majority of electricity generation in Nigeria comes from fossil fuels, with about two-thirds of thermal power derived from natural gas and the rest from oil, resulting in the emission of carbon dioxide (𝐶𝑂2). With the prevailing global climate change, shifting to renewable energy would reduce the greenhouse gas emission which would be the salvaging option to help our degrading environment. The aim of the resource’s hybridization process is to generate enough electricity that would help the supplementing for the inadequate electricity supply in the local province at the least detrimental effect on the environment. This work discusses the renewable energy potential of Nigeria and raises the possibility of having Nigeria electricity grid powered by small, medium and large-scale renewable energy systems. The hybridised power generation system simulations were done using HOMER simulation software. The hybridisation of the resources was able to generate 149,313 kWh/yr to adequately sustain the estimated electrical load of 126,027kWh/yr. Conclusively, cost effectiveness of the individual and hybridised systems was also considered.

Effects of Concrete Grades on Strength Characteristics of Metakaolin Modified Recycled Aggregate Concrete

In this study, locally produced Metakaolin (MK) was used as an admixture in recycled aggregate concrete of grades M 25 and M 30. The content of MK varied from 0-15% at 5% intervals. The physical and mechanical properties (bulk density, specific gravity, water absorption, aggregate crushing value and aggregate impact value) of aggregates were determined, the chemical composition as well as reactivity of MK was evaluated using X-Ray Fluorescence (XRF) technique and modified Chappelle test. The workability (slump) and strength (compressive and split tensile) properties of fresh and hardened RAC were examined relative to that of conventional concrete. The results of the experiments revealed that the specific gravity (SG), water absorption and aggregate impact value of recycled aggregates (RA) were 2.23, 5.35% and 32%, respectively. The MK used had an optimum reactivity of 2060.8 mg of Ca(OH)2 fixed at a temperature of 660 oC. The slump values for M 25 and M 30 control specimens were 72 mm and 65 mm, respectively while the slump values of MK modified RAC decreased from 67-45 mm for M 25 and 55-35 mm for M 30 as MK increased from 0-15%. The 56th-day compressive strength of the control samples was 21.73 N/mm2 for M 25 and 26.8 N/mm2 for M 30, respectively, while RAC samples ranged from 14.96 - 17.04 N/mm2 for M 25 and 20.55 - 22.67 N/mm2 for M 30 whereas the split tensile strength for the control samples was 2.71 N/mm2 and 3.06 N/mm2 for the two grades in that sequence, while those of RAC ranged from 2.26-2.49 N/mm2 for M 25 and 2.62 – 2.84 N/mm2 for M 30. Despite the fact that metakaolin modified RAC had lower strength properties than conventional concrete, the use of 10% metakaolin as a RA modifier in concrete production will provide a sustainable alternative to conventional aggregates in concrete mix design.

Deltaic Lateritic Soil in 1:5:11 Mix Design for Producing Controlled Low-Strength Material (CLSM) for Pavement Backfill

Deltaic lateritic soil obtained from Emohua in Rivers State, Nigeria was studied to ascertain its suitability as a substitute to sand in concrete for producing controlled low-strength material (CLSM). Cement, coarse aggregate, as well as lateritic soil which replaced sand was combined in ratio 1:5:11 to produce lateritic concrete using varying water-cement (w/c) ratios at varying curing durations. Variation in the w/c ratios ranging from 0.2 to 0.5 at 0.1 intervals and the curing periods which varied between 7, 14 and 28 days were examined. As with the case with conventional concrete, strength development, as well as cement hydration took place after casting over the curing periods. Recent applications using CLSM recommends that a compressive strength of 8.3 N/mm2 or less is required for materials used as conventional compacted backfill soil or structural fillings. In a situation where future excavation is envisioned, it is recommended that the maximum long-term compressive strength of CLSM should generally have an upper limit of 2.1 N/mm2 for compacted backfill material hence, the lateritic concrete produced in this study using the 1:5:11 mix design at 0.2 w/c ratio, cured for 28 days which gave strength of 5.3 N/mm2 can be used as CLSM which primarily, can be utilized as a substitute for compacted backfill to sub-base and/or subgrade of flexible pavements. Where necessary, super plasticizer can be introduced to increase flowability of the lateritic concrete.

Modelling the Deformation of Steel-bars in Reinforced Concrete Beams Submerged in Lagoon

Corrosion of steel and spalling of concrete in reinforced concrete elements have become a common occurrence in structures that are built around marine environment. This research investigated the effect of chloride on the steel in reinforced concrete beams. Mechanical tests such as; compressive, flexural and bond strengths were done on replicate concrete elements which were cast and buried for a maximum of one year in the Lagos lagoon. Twenty-four number of 150 mm x 150 mm x 600 mm sized reinforced concrete beams were cast for the flexural strength test, while forty-eight concrete cubes were cast for both compressive and bond strength tests, samples were cured in both lagoon and fresh water (The fresh water is for the control). A finite element program, ANSYS was used to model the deformation (deflection) of the steel reinforcement in the beams. Results showed a general reduction in compressive, flexural and bond strengths for the concrete samples buried in the lagoon, while those buried in freshwater showed an increase in strength as the concrete ages. The modelled results of the reinforcement showed a one-year deformation rate (r = 0.0181) in the steel of concrete buried in lagoon water. This value was used to estimate the future and past deformation values of these reinforcements due to chloride attack.