Design and development of a permanent mould for crucible production

This study aimed at development of a permanent mould for crucible production. Solid-Works was used as the computer aided design (CAD) tool for design and structural analysis of the parts, with necessary design considerations put in place. The fabrication of the mould was carried out at Federal Institute for Industrial Research Oshodi (FIIRO), selecting Mild steel as the parent material. The mould basically consisted of the male and female parts made up of medium carbon steel because of the required strength. It was discovered from the structural analysis that the application of 1.0783 MN/m2 to produce the crucible from the mould is safe because it is not up to the vonmises maximum pressure of similar load of 5.584 MN/m2 , this is lesser than the yield strength of the material which is given to be 2.481 MN/mm2 . This shows that the material and its specification is safe and will not fail for the purpose for which it is designed for. Results showing the displacement and strain analysis revealed that the displacement in the mould is in the rate of 0.001 MN/mm and 0.00173 mm. This displacement is insignificant to cause failure in the part. And the strain is seen to be in the range 2.176 X 10-8 and 2.232 X 10 -5 , the results therefore give confidence in the design to meet requirement. Keywords: Casting, Development, Foundry, Crucible, Mould, SolidWork

Review on hardfacing as method of improving the service life of critical components subjected to wear in service

A review on hardfacing is presented. Hardfacing involves applying a consumable with desired wear properties over a soft base metal surface to enhance resistance to different wear mechanisms. Substrate materials used for hardfacing are mainly steel, while the alloys of carbide forming elements dominate the surfacing consumables. Powder metallurgy, atomisation and granulation are methods of producing hardfacing alloy powder. Most welding methods were identified to be successfully used in applying consumable on substrate surfaces. Dilution decreases with increase in the number of hardfacing layers. Buffers, butters and build-up metals are used to compensate for composition differences to prevent spalling, overcome welding difficulties and make up for badly worn surfaces, respectively. Waffle, stringer and dot patterns are the existing hardfacing deposit patterns. Benefits of hardfacing include: reduced downtime, inventory and maintenance cost, increased plant availability and productivity, and a good number of service life extensions through timely reparation.Keywords: Hardfacing, wear, substrate, consumable, service life extension, composition compensatio

Determination of work index of graphite from Samanburkono (Nigeria) using modified bond's method

This report covers the work index determination of Saman-Burkono graphite. The test sample was obtained from Saman-Burkono in Ningi Local Government Area of Bauchi state, while reference material (coal) was sourced from Okaba coal mine, Ankpa Local Government Area of Kogi State. A known weight of graphite sample and coal were crushed, pulverized and ground using the laboratory milling machine. The two samples were grinded with two cells of diameter 3.5cm and 222g weight. The analysis of the feed size fort the two samples was found graphically to be 180μm and 175μm, and ball mill discharge was 130μm and 140μm respectively. The work index of a coal as reference material was 7.65 kWh/ short ton, this was used to calculate the work index of the graphite which was found to be 11.047 kWh/short ton, being the required energy to comminute one ton of graphite.Keywords: Comminution, Graphite, Saman-Burkono, Nigeria, Modified Bonds metho

Modelling of clinker cooler and evaluation of its performance in clinker cooling process for cement plants

Cement manufacturing requires cooling down of hot clinker at temperature of about 1350o C to temperature lower than 100 o C in a cooling system known as clinker cooler. Many plants are unable to cool the clinker below 250o C. This challenge led to scaling down of actual clinker cooler to a test rig size in the ratio 25:1 suitable for simulation. Computational Fluid Dynamics (CFD) tools (Solid-Works and ANSYS) were used to achieve the simulation. The clinker outlet temperatures obtained from simulations were validated with theoretical evaluation. Results showed that with clinker and cooling air flow rates of 0.2 kg/s and 0.54 kg/s respectively and with a clinker bed height of 0.6 m. An optimum cooler performance was achieved with clinker outlet temperature of 68 oC. The scaled down cooler was 15% higher than the existing cooler in terms of recoverable energy and 10% high in terms of energy efficiency. Keywords: Clinker Cooler, Computational Fluid Dynamics (CFD), Mass flow rate clinker and Mass flow air and Clinker Furnace

Investigation and validation of consumer device accelerometers for the assessment of whole-body vibration

There exist a discrepancy between the usage of the expensive standard accelerometer and the cheap and accessible consumer device accelerometer for the measurement of whole-body vibration (WBV). This study investigated the validity of accelerations (g-forces) obtained from a consumer device accelerometer by simultaneously using the consumer device accelerometer with a standard accelerometer during evaluation of WBV experienced by earthmoving equipment operators. The consumer device accelerometer is a software (WBV) compatible with iOS devices from operating system 5 and above (LIS331DLH, 3-axis, ±2 g acceleration range, MEMS type) while the standard accelerometer used during this study is a GCDC tri-axial accelerometer (GCDC X16-4 3-Axis, G-Force Data logger, ±18 g acceleration range, MEMS type). The two accelerometers were mounted following the basicentric axes of the seated operators and put on before earthmoving operation. Data from both the accelerometers were analysed using MATLAB. Results gotten from both accelerometers revealed extreme values of WBV. Some fell within the Health Guidance Caution Zone (HGCZ i.e. 0.47 m/s2 and 0.93 m/s2) while some were above 0.93 m/s2. There were however differences between values gotten from the two accelerometers indicating inaccuracy from the consumer device accelerometer. This research created ground for improvement of accelerometers available on mobile devices and perhaps waken the need for developing new and economic methods of WBV measurement and evaluation

Database management system for mobile crowdsourcing applications

The evaluation of mobile crowdsourcing activities and reports require a viable and large volume of data. These data are gathered in real-time and from a large number of paid or unpaid volunteers over a period. A high volume of quality data from smartphones or mobile devices is pivotal to the accuracy and validity of the results. Therefore, there is a need for a robust and scalable database structure that can effectively manage and store the large volumes of data collected from various volunteers without compromising the integrity of the data. An in-depth review of various database designs to select the most suitable that will meet the needs of a real-time, robust and large volunteer data handling system is presented. A non-relational database was proposed for the mobile- end database: Google Cloud Firestore specifically due to its support for mobile client implementation, this choice also makes the integration of data from the mobile end-users to the cloud-hosted database relatively easier with all proposed services being part of the Google Cloud Platform; although it is not as popular as some other database services. Separate comparative reviews of the Database Management System (DBMS) performance demonstrated that MongoDB (a non-relational database) performed better when reading large datasets and performing full-text queries, while MySQL (relational) and Cassandra (non-relational) performed much better for data insertion. Google BigQuery was proposed as an appropriate data warehouse solution. It will provide continuity and direct integration with Cloud Firestore and its Application Programming Interface (API) for data migration from Cloud Firestore to BigQuery, and the local server. Also Google BigQuery provides machine learning support for data analytics

Whole-body vibration exposure on earthmoving equipment operators in construction industries

Operators of Earthmoving Equipment (EME) are daily exposed to certain Whole-body vibration (WBV) dosage, exceeding the recommended values. In this study, the WBV experienced by operators of EME used in construction industries were measured using a tri-axial accelerometer (GCDC X16-4 3-Axis, G-Force Data logger, ±18 g acceleration range). These measurements were taken on the seats and floors of EME in x, y and z directions. Weighted root-mean-square accelerations (A RMS), Vibration dose values (VDVs), Crest Factors (CFs), time to reach health guidance caution zone (HGCZ) which are important evaluation parameters specified by the International Organiization for Standardization (ISO) were determined for each equipment used in the study. The values of the CF were mostly found to be greater than 9 indicating presence of multiple shocks during the operation of the equipment studied. The research revealed higher magnitude of acceleration in the vertical, z-axis, some very few are within the HGCZ (A RMS 0.93 m/s2; VDV 17 m/s1.75) specified by ISO, also accelerations on x- and y-axes fell within the HGCZ and very few below the lower limit 0.47 m/s2. The values of the A RMS and VDV were also compared with the European Parliament Directive 2002/44/EC (A(8) 2.5 m/s2; VDV 21 m/s1.75). Appropriate technology should be adopted to minimize the WBV reaching operators, and/or appropriate maintenance routine should be maintained in EMEs to combat the health risks associated with WBV