Effect of Expression Conditions on the Yield of Dika Nut (Irvingia Gabonesis) Oil under Uniaxial Compression

Efficient expression of Dika nut oil from the kernel is required for its subsequent use in producing comparatively cheap lubricant. Various factors responsible for proper oil expression include particle size, moisture content, heating temperature, heating time, pressing pressure and pressing time. Sundried Dika kernel ground to two particle sizes (fine: ≤ 1.4 mm and coarse: between 1.4 and 2.8 mm) were conditioned to moisture content of 3, 6 and 9 wt%. Considered in the study, are heating temperature ranging from 50 to 150oC in steps of 25 degrees Celsius and heating time of 5 to 25 minutes in steps of 5 minutes. Pressing pressure of 5 to 25 MPa in steps of 5 MPa and pressing time of 2 minutes interval were also considered. The maximum oil yield was then correlated with the processing conditions. Test results showed that coarse particle gave higher oil yield. Maximum oil yield of 72.2% of the available oil was obtained at 6% moisture content, heating temperature of 100oC and heating time of 10 minutes. Regression analyses of the oil yield with heating temperature, heating time, and pressing gave r2 values of 0.9678, 0.999 and 0.9128. The processing conditions therefore has significantly influence the quantity of oil obtained from Dika kerne

Dika nut oil as base oil for lubricants—effect of processing conditions on physicochemical properties

The paper presents a report on the effect of processing conditions of Dika nut oil on its physicochemical properties and also on the assessment of the oil for use as biodegradable lubricant. The oil was expressed mechanically from coarsely ground kernel meals at 3 and 9 wt.% moisture content (wet basis), preheated at 75, 100 and 150 °C for 10, 20 and 30 min. The plots showed that the chemical properties of the oil had quadratic and linear relationships with the heating temperature and heating time, respectively. At 95% confidence level, the free fatty acid content, the saponification, the iodine and the acid values of the oil were significantly affected by various processing conditions. The processing conditions therefore showed significant influence on the physicochemical properties of the oil and consequently on its suitability for use as lubricant. Copyright © 2012 John Wiley & Sons, Ltd

Computer Aided Plumbing Design

This study has been used to eliminate the rigorous activities and time consuming mathematical analysis involved in Plumbing design. The various mathematical steps employed in the design of plumbing systems has been converted into easily interpreted hand user computer program that can be used to generate automatically all the various parameters needed for full design work, when the input data such as head available, various number of fittings, actual length of pipe run and assumed pipe diameter are provided. This has been used to provide a pathway to easy plumbing desig

Separation theory for palm kernel and shell mixture on a spinning disc

The separation of palm kernel from the shell is an important process in the recovery of the kernel for use in vegetable oil production. The inherent shortcoming of the fertiliser spinner spreader, resulting in non-uniform distribution, has led to investigations into the possibility of its use in the separation of palm kernel from shell. The differences in the physical properties of the kernel and shell provided the basis for separation. Models describing the motion of the kernel and the shell on a spinning disc with vanes, feeding a segment at a time, were developed, and comparisons between the predictions and experimental results were made. Discharge angles obtained from the predictive models and from the experiment were in close agreement. The experiment, however, indicated a mid-span, between the discharge angles for kernels and shells, containing the mixture. The models reasonably predict approximate ranges of discharge angles for palm kernels and shells on a spinning disc with specified diameter, friction coefficient and rotational speed

Mathematical modelling of palm nut cracking based on Hertz's theory

A mathematical model based on Hertz's theory of contact stress was developed for the prediction of force required to break the palm nut. Using nuts subjected to a uniaxial compression stress, in their lateral axis between rigid parallel plates, and those propelled to impinge a rigid cylindrical seat along its lateral axis, experimental verification of the model was conducted comparing the theoretical predictions with estimates from the representations of conventional methods employed in nut cracking. Properties including size, shape and mass, required in the derived model were determined for two varieties of the palm nut. Material stiffness was obtained from the force–deformation curve. Regression analysis showed an exponential variation of the cracking force with nut deformation. Material stiffness obtained was 654 N/mm and 303 N/mm for the ‘Dura’ and ‘Tenera’ nuts, respectively. The respective ranges of geometric mean diameters were 17·07–27·68 mm and 22·32–26.51 mm. There was no significant variation of nut sphericity with size or variety. Force prediction from the Hertzian model proposed gave good prediction of cracking force that was not significantly different from that obtained from a centrifugal nutcracker driven at 1500 min−1, with a 40 cm diameter cracking chambe

A Table Mounted Device for Cracking Dika Nut (Irvingia gabonensis)

A simply designed machine for cracking dika nut was fabricated. The nut is fed by hand inbetween a toggle mechanism comprising of the slider and a fixed block. Fracture mechanism was based on the deformation characteristics of dried dika nut under uni-axial compression. When actuated, the slider compresses the nutshell to failure along its line of symmetry. The experimental machine gave 100% cracking efficiency but with 24% kernel breakage in cracking sun-dried dika nut at 6.6% moisture content (w.b). The machine provides a viable and effective technique for safe dika kernel extraction

Design, fabrication and testing of a cassava pelletizer

This paper reports on the design of fabrication and testing of a machine for cottage level production of pellets from cassava mash. The pelletizer consists of a barreled screw auger which compresses cassava mash against perforated end plate, through which the pellets are pelletized. The result derived from the calculated design parameters (shaft diameter, tensile stress, torque, screw length, volumetric capacity mass flow rate and power rating) were used for the fabrication. The testing of the pelletizer was determined in terms of throughput of the machine, against the moisture content of the mash (18, 20 and 22% wb), die size (4, 6 and 8 mm) and the auger speed (90, 100 and 120 rpm). Test results showed that the pellets with the best quality attributes were obtained from cassava mash at 18% moisture content (wb) through the 4 mm die at 90 rpm and a maximum throughput of 54 kg/h

A table mounted device for cracking dika nut (Irvingia gabonensis)

A simply designed machine for cracking dika nut was fabricated. The nut is fed by hand inbetween a toggle mechanism comprising of the slider and a fixed block. Fracture mechanism was based on the deformation characteristics of dried dika nut under uni-axial compression. When actuated, the slider compresses the nutshell to failure along its line of symmetry. The experimental machine gave 100% cracking efficiency but with 24% kernel breakage in cracking sun-dried dika nut at 6.6% moisture content (w.b). The machine provides a viable and effective technique for safe dika kernel extraction

Deformation and Dehulling of Sponge Gourd (Luffa aegyptiaca) Seeds

This work presents the compressive strength properties of sponge gourd (Luffa aegyptica) seeds to facilitate the design or adaptation of an appropriate dehuller. The sizes and shape indices of the seed and kernel, and the clearance of the kernel from the seed coat were determined. The seed samples were subjected to uni-axial quasi-static compression tests at 1.0 mm min−1 along the minor and the major axes. The fracture resistance, stiffness modulus, modulus of elasticity, toughness, and maximum elastic deformation of the seed were obtained from the force-deformation curve. The geometric mean diameters varied from 4.0 to 4.5 mm for the seed and 1.6 to 3.9 mm for the embedded kernel; while their corresponding sphericities were 0.64 and 0.62, respectively. The compressive strength of the seed varied with loading orientation. The seed exhibited larger deformation but lower stiffness along the major axis than the minor axis. The force required for rupturing the hull were 95 N along the major axis and 81 N along the minor axis; while the corresponding energy required were 95 and 40 m