LAUTECH Journal of Engineering and Technology

EXPERIMENTAL INVESTIGATION OF THE POTENTIAL OF LIQUIFIED PETROLEUM GAS IN VAPOUR COMPRESSION REFRIGERATION SYSTEM

2023-03-24T15:42:50+00:00

The essence of refrigeration systems cannot be overemphasized especially in this part of the globe. Perishable items are to be preserved for some periods before usage while human comfort should also be also be paramount since we are in the northern hemisphere of the globe. The device hat doe this uses refrigerants as working fluids which are traditional harmful to human beings through depletion of the ozone layer. Majorly Ozone layer protects the earth from warming which could lead to flooding. Common economical refrigerants like CFCs (Chlorofluorocarbons) have been discovered to be harmful to the earth. This article therefore, experimented the quantity replacement of CFCs with Liquefied Petroleum Gas in various mixes. The LPG (Liquefied Petroleum Gas) used consists a mixture of propane and butane in the ratio 6:4 by mass. The blend of the two refrigerants were shaped essentially by blending at least two single-part refrigerants, the GWP (Global Warming Potentials) of a refrigerant mix is the mass-weighted normal of GWPs of individual parts in the mix. That is, to compute the GWP of a mix, one essentially adds the GWP of the singular parts with respect to their (GWP (LPG) x M (LPG)) + (GWP(R-134a) x M(R-134a)) = GWP (blend). From the evaluated GWP of the 6 different % mass composition, the % mass of (100%/0%) was the only refrigerant to adhere to the preferred GWP<150. The mass composition of blend (100%/0%) LPG/R-134a was first performed. In-order to achieve this, 8kg of each of the refrigerant was used. The blend was formed in an empty cylinder which was measured as 2482g with the aid of a digital beam balance, by gradually injecting LPG into the empty cylinder till the mass percentage of the 2000g entered, making the mass read as 4,482g (i.e., 2482g of the empty cylinder + 2000g of LPG). Based on the above observations, it could be inferred that the COP (Coefficient of Performance) of mixed refrigerants blends was higher than that of R-134a indicating that each of the blend exhibit higher performance. The experiment discovered that LPG could be used in the place of R134a without affecting the operation efficiency of a vapor compression refrigeration system. The study concludes that LPG offers the best alternative when the COP and flammability are combined as performance metrics

DESIGN AND PRODUCTION OF ASBESTOS FREE BRAKE PAD USING CASHEW NUTSHELL

2023-03-24T16:07:31+00:00

A brake is a mechanical device used in controlling the speed of a moving vehicle using a frictional material and dissipates the absorbed kinetic energy as heat to the surroundings. A new brake pad composition has been developed with the Cashew Nutshell (CNSL), Silicon Carbide (SC), Steel Dust (SD), Carbon Black (CB), Epoxy Resin and Hardener (ERH). Five different samples of varying constituents were made with two different sieve sizes for each sample was investigated. The result showed that sample D of the 100 μm with composition 55g of (CNSL), 15g of (SC), 10g of (SD), 5g of (CB) and 15g of Epoxy resin and hardener had the best properties. The Brinell hardness value, Coefficient of Friction, Porosity, Ash content, Density and Wear rate were 75.65, 0.3528 1.925, 45.6, 1.521 kg/m³ for 100 μm and 1.17 respectively. These values are acceptable, though the 75μm samples fared better in many of the test results but lacked in the aspect of density when compared with the other sieve grades. This shows that Cashew Nutshell can be used as filler in the production of eco-friendly brake pads.

CHARACTERISATION OF THE NIGERIAN-GROWN EUCALYPTUS CAMALDULENSIS TIMBER SPECIE ACCORDING TO EN 338 (2009) AND NCP 2 (1973)

2023-04-04T21:25:21+00:00

In this work, the Nigerian-grown Eucalyptus camaldulensis timber specie was characterized based on the NCP 2 (1973) and EN 338 (2009) code. The specie was obtained from timber markets in Sabon Gari, Zaria and Fanteka, Kaduna, North-western Nigeria. The elastic modulus, bending strength (using four-point flexural test) and density of the timber as stated in EN 384 (2004) were determined at their various moisture contents with which other respective derived properties were obtained. The experiments were carried out using a 500 kN capacity Universal Testing Machine at the Department of Civil Engineering laboratory, Ahmadu Bello University, Zaria. Results obtained indicate that the mean density of Eucalyptus camaldulensis timber is 975.9 kg/m³at an adjusted moisture content of 18%. The flexural strength of Eucalyptus camaldulensis timber species was determined to be 69.02 N/mm² and the mean Modulus of Elasticity of 5409.4 N/mm². With these results, Eucalyptus camaldulensis was allocated to strength class D60 based on EN 338 (2009) and strength class N1 based on NCP 2 (1973) classification systems which makes it suitable for bridge construction, railway sleepers, pier construction as well as heavy duty flooring.

OPTIMAL ROUTE DETERMINATION FOR POSTAL DELIVERY USING ANT COLONY OPTIMIZATION ALGORITHM

2023-04-14T17:37:43+00:00

There are a lot of optimization challenges in the world, as we all know. The vehicle routing problem is one of the more complex and high-level problems. Vehicle Routing Problem is a real-life problem in the Postal Delivery System logistics and, if not properly attended to, can lead to wastage of resources that could have been directed towards other things. Several studies have been carried out to tackle this problem using different techniques and algorithms. This study used the Ant Colony Optimization Algorithm along with some powerful APIs to find an optimal route for the delivery of posts to customers in a Postal Delivering System. When Ant Colony Optimization Algorithm is used to solve the vehicle routing problem in transportation systems, each Ant's journey is mere “part” of a feasible solution. To put it in another way, numerous ants' pathways might make up a viable solution. Routes are determined for a delivery vehicle, with the objective of minimizing customer waiting time and operation cost. Experimental results indicate that the solution is optimal and more accurate

A DUAL-TRIGGER SMART HAND WASHING MACHINE

2023-04-14T18:05:47+00:00

Hand washing is simple and effective in preventing the transmission of infection and sickness in various contexts, including the home, workplace, childcare facilities, and hospitals. It is important to note that contaminated surface like tap heads and manually operated hand sanitizer pose threat to the users of such facility and as such has constituted a global concern due to the emergence of diseases that can be easily transmitted. Hence, this project presents a low-cost automatic hand washing machine with a temperature sensor and counter, triggered by an Ultrasonic sensor and Laser-Light Dependent Resistor (LDR) trip wire that puts ON or OFF the pump and counting at the same time. The system design was done in two levels, the 3D model and circuit diagram design: firstly, the 3D model design was done with Autodesk Inventor 2017 while the circuit diagram design was done using Fritzing software and simulations performed for both levels. The system was fabricated and evaluated; the result obtained revealed reliable water dispense since the water flow can be activated by either an ultrasonic or laser-LDR sensor, a strong frame at a threshold weight of 166.6 N, and reliable temperature measurement. The uniqueness of this work is that it combines automated temperature measurement, hand-washing, and counting systems in a single device. Temperature measurement and hand-washing help to prevent disease spread while the counting system assists in recording the number of people using or entering a facility to aid the practice of social distancing as means of curtailing the spread of the diseases.

A HYBRIDIZED ENCRYPTION SCHEME BASED ON ELLIPTIC CURVE CRYPTOGRAPHY FOR SECURING DATA IN SMART HEALTHCARE

2023-04-14T21:02:56+00:00

Recent developments in smart healthcare have brought us a great deal of convenience. Connecting common objects to the Internet is made possible by the Internet of Things (IoT). These connected gadgets have sensors and actuators for data collection and transfer. However, if users' private health information is compromised or exposed, it will seriously harm their privacy and may endanger their lives. In order to encrypt data and establish perfectly alright access control for such sensitive information, attribute-based encryption (ABE) has typically been used. Traditional ABE, however, has a high processing overhead. As a result, an effective security system algorithm based on ABE and Fully Homomorphic Encryption (FHE) is developed to protect health-related data. ABE is a workable option for one-to-many communication and perfectly alright access management of encrypting data in a cloud environment. Without needing to decode the encrypted data, cloud servers can use the FHE algorithm to take valid actions on it. Because of its potential to provide excellent security with a tiny key size, elliptic curve cryptography (ECC) algorithm is also used. As a result, when compared to related existing methods in the literature, the suggested hybridized algorithm (ABE-FHE-ECC) has reduced computation and storage overheads. A comprehensive safety evidence clearly shows that the suggested method is protected by the Decisional Bilinear Diffie-Hellman postulate. The experimental results demonstrate that this system is more effective for devices with limited resources than the conventional ABE when the system’s performance is assessed by utilizing standard model.

OPTIMIZING THE USAGE OF RENEWABLE ENERGY FOR POWERING OFFSHORE OIL FIELDS

2023-05-24T12:59:05+00:00

Carbon dioxide (CO₂) emission due to power generation from fossil fuel is a major contributor to the current issues of global warming and climate change. This paper proposes offshore generation of electricity from renewables to supply offshore oil fields. An existing oil field in the UK North Sea was assumed and a hybrid power system consisting of power from wind, wave, and fossil fuel generators was dedicated to it. The feasible/economical reduction in CO₂ emission was investigated by using Homer Pro software to model and simulate performance of the micro-grid. Data of the renewable resources are specific to the selected site. From the simulation results, a solution with the lowest net present cost (winning system) was chosen and compared with the base case system to observe how the hybrid system saves cost over the project lifetime. The winning system was refined as much as possible to develop the optimal system which was proposed for implementation. This system demonstrated its economics relative to the base case system as the annual fuel consumption and the corresponding CO₂ emission dropped by 38% each. Likewise, the cost of energy fell by 42%. Imposition of carbon tax was recommended to boost the development of renewables.

FREQUENCY AND VOLTAGE RESPONSES OF GAS-FIRED DISTRIBUTED GENERATION SYSTEM TO LOAD

2023-05-24T15:11:53+00:00

Research has shown that addition of loads to a distributed generation (DG) system operating either in stand-alone mode (SAM) or grid-connected mode (GCM) has impacts on its operations. This paper analyzed the voltage and frequency responses of the DG when operated in stand-alone and grid-connected modes under load variations. Mathematical equations showing the characteristics of the DG under varying loads with the two modes were developed. The equations were modeled using MATLAB in Simulink environment. By applying gradual and sudden loads using 2MW DG and an 11kV distribution grid network, the frequency and voltage responses under the two modes were calculated. The results showed that with gradual load addition from 10 to 100 % loading, the output frequency varied from 49.72 to 49.27 Hz (-0.56 to -1.46 %) for SAM while it varied for GCM from 49.90 to 49.44 Hz (-0.20 to -1.12 %). Output voltage varied from 376 to 232.9 V (-6.0 to -41.78 %) for 10 to 100 % load respectively for SAM while it varied from 387.7 to 268.3 V (-3.08 to -32.93 %) for GCM. For sudden load additions, the output frequency variation was between 49.39 to 49.25 Hz (-1.22 to -1.5 %) for 25 to 100 % load for SAM while that of GCM was between 49.51 to 49.43 Hz (-0.98 to -1.14 %); voltage variation was 271.7 to 190 V (-32.08 to -52.5 %) for 25 to 100 % load respectively for SAM while that of GCM was 294.2 to 219.9V(-26.45% to -45.03%). The results revealed that the frequency with gradual and sudden load additions for SAM and GCM varied outside the operational limit of 49.75-50.25 Hz () except in the case of 10 % load under gradual load addition in GCM. However, the frequency and voltage variation are less in GCM than SAM with gradual and sudden load additions

OPTIMAL PLACEMENT OF UNIFIED POWER FLOW CONTROLLER ON POWER SYSTEM FOR VOLTAGE STABILITY ENHANCEMENT USING ARTIFICIAL NEURAL NETWORK TECHNIQUE

2023-05-27T12:10:28+00:00

The desire for an enhanced power transfer capability and quality of electricity delivered to the customers has led to emergence of Flexible Alternating Current Transmission Systems (FACTS). This work compares power system voltage stability with and without compensation. The compensation is done by optimal placement of Unified Power Flow Controller (UPFC) using Artificial Neural Network (ANN) technique. The algorithm to implement the stabilizing processes employed Newton-Raphson-based load flow equations in MATLAB R2018a environment. The stability of Nigerian 330 kV, 30–bus network was assessed before and after the implementation of UPFC and UPFC-ANN controlled. The results obtained without compensation showed: New Haven, Onitsha, Gombe, Jos, Kano and Calabar with voltage magnitude of 0.9003, 0.9468, 0.6608, 0.8141, 0.8138 and 0.9319 p.u, respectively violated the statutory limit of 0.951.05 p.u and total active power loss was 218.76 MW. With UPFC on bus Calabar, the total active power loss reduced to 200.85 MW, while buses New Haven, Gombe, Jos and Kano produced voltage magnitude of 0.9130, 0.6608, 0.8141 and 0.8138 p.u, respectively, still constrained. ANN based UPFC placement on bus Gombe - the most critical bus with Voltage stability index (VSI) of 0.9252, the voltage magnitude of buses New Haven, Onitsha, Gombe, Jos, Kano and Calabar enhanced to 0.9533, 0.9552, 1.0481, 1.0399, 1.0425 and 1.0081 p.u, respectively and total active power loss reduced by 28.81% compared with 8.19% reduction with UPFC. The study revealed ANN controlled UPFC is suitable and appropriate for improving voltage stability and reducing power loss on power system.