Effects of Engineering Properties on the Poppability of Nigerian Popcorn

2009 ◽  
Vol 5 (1) ◽  
Author(s):  
Taiwo Falilat Ademiluyi ◽  
Horsfall Doopue Mepba

The effects of some engineering properties on the poppability of three Nigerian popcorn hybrids were investigated. Properties such as moisture, porosity, bulk density, kernel size and ingredient used in popping were found to affect the popping volume of Nigerian popcorn. Popped ratio and popping volume increased with increasing moisture contents and reaching a peak at 14.0% moisture, then declined progressively. Sugar treatments increased popping volume while salt treatment increased popped ratio. Kernel bulk densities ranged from 730 – 860 kg/m3 and declined linearly with increased moisture contents. Local hybrids (4.43 – 5.75 mm in diameter) had specific heat capacity, porosity and popping time ranging from 1.84 ± 0.2 – 1.87 ± 0.2 kJ/kg K, 38.8 ± 0.2 – 42.9 ± 0.2% and 110 ± 0.1 – 129.0 ± 0.1 seconds, respectively. Smaller size kernels had the highest popped ratios while medium size kernels had the highest popping volume. The Nigerian popcorn hybrids were rich in carbohydrate (60.7 ± 0.3 – 64.0 ± 0.4%), protein (8.3 ± 0.3 – 8.7 ± 0.2%), fat (6.6 ± 0.2 – 8.8 ± 0.2%) and crude fiber (2.9 ± 0.2 – 3.9 ± 0.1%). The deep yellow Nigerian popcorn hybrid was rated significantly (P ? 0.05) higher than all the local varieties and foreign type for crispiness, taste, mealiness, flavour/aroma, and overall acceptability characteristics. Generally, Nigerian popcorn hybrid compared favourably with the foreign type for colour and overall acceptability characteristics but were rated significantly (P ? 0.05) higher for crispness.

Author(s):  
G. O. Ogunlakin ◽  
E. H. Onibokun ◽  
B. Fashogbon

Sorghum (red and white) were germinated for 24, 48, 72, and 96 h to determine the effect of germination on some functional and engineering properties of sorghum flour. The bulk density results for the red and white germinated sorghum are 0.620-0.673 g/cm3 and 0.477-0.620 g/cm3, respectively. Water absorption capacity values for the two samples are 116.630-125.970% and 81.643-98.293% while the oil absorption capacity ranged from 62.917 to 85.750% and 44.933 to 61.980%, respectively for the two samples. The dispersibility test for the two samples gave 85.67-87.33% and 83.00-84.67%. The swelling power at 55 °C are 2.54-2.67 and 2.70-3.26, at 75 °C, 3.62-4.68 and 3.85-4.56, and at 90 °C, 2.98-4.79 and 6.29-7.23, respectively for the two samples. For the engineering properties, the specific heat capacity ranged from 0.14 to 0.45 kJ/kg K and 0.12 to 0.14 kJ/kg K, thermal conductivity, from 0.55 to 1.67 W/mK and 1.01 to 1.24 W/mK and thermal diffusivity from 0.13 to 0.82 m2/s and 0.11 to 0.12 m2/s, respectively for red and white germinated sorghum flours. It can be concluded from this study that increased the values of bulk density, WAC, OAC, and dispersibility test of the two samples with the increase in germination period with the optimum germination period of 72 h. Engineering properties results indicated that germination had a beneficial effect on the thermal conductivity of the germinated red sorghum and the thermal conductivity and specific heat capacity of the white germinated sorghum with 96 h having the best result for both samples.


2020 ◽  
Vol 7 ◽  

The ability to monitor soil heat capacity is an important mean in managing the soil temperature regime, which in turn, affects its ability to store heat. The effect of water content and bulk density on the specific heat and volumetric heat capacity of two Saudian soils (sand and loam) was investigated through laboratory studies. These laboratory experiments used the calorimetric method to determine specific heat of soils. For the type of soils studied, specific heat increased with increased moisture content. Also, volumetric heat capacity increased with increased moisture content and soil density. Volumetric heat capacity ranged from 1.55 to 3.50 for loam and from 1.06 to 3.00 MJ/m3 / o C for sand at moisture contents from 0 to 0.20 (kg/kg) and densities from 1200 to 1400 kg/m3 . Specific heat ranged from 1140 to 2090 for loam and from 800 to 1530 J/kg/ oC for sand at moisture contents from 0.01 to 0.20 (kg/kg) and soil density of 1200 kg/m3 . The volumetric heat capacity and specific heat of soils observed in this study under varying moisture content and soil density were compared with independent estimates made using derived theoretical relations. The differences between the observed and predicted results were very small. Loam soil generally had higher specific heat and volumetric heat capacity than sandy soil for the same moisture content and soil density.


Author(s):  
V.N. Moraru

The results of our work and a number of foreign studies indicate that the sharp increase in the heat transfer parameters (specific heat flux q and heat transfer coefficient _) at the boiling of nanofluids as compared to the base liquid (water) is due not only and not so much to the increase of the thermal conductivity of the nanofluids, but an intensification of the boiling process caused by a change in the state of the heating surface, its topological and chemical properties (porosity, roughness, wettability). The latter leads to a change in the internal characteristics of the boiling process and the average temperature of the superheated liquid layer. This circumstance makes it possible, on the basis of physical models of the liquids boiling and taking into account the parameters of the surface state (temperature, pressure) and properties of the coolant (the density and heat capacity of the liquid, the specific heat of vaporization and the heat capacity of the vapor), and also the internal characteristics of the boiling of liquids, to calculate the value of specific heat flux q. In this paper, the difference in the mechanisms of heat transfer during the boiling of single-phase (water) and two-phase nanofluids has been studied and a quantitative estimate of the q values for the boiling of the nanofluid is carried out based on the internal characteristics of the boiling process. The satisfactory agreement of the calculated values with the experimental data is a confirmation that the key factor in the growth of the heat transfer intensity at the boiling of nanofluids is indeed a change in the nature and microrelief of the heating surface. Bibl. 20, Fig. 9, Tab. 2.


2019 ◽  
Vol 15 ◽  
Author(s):  
Andaç Batur Çolak ◽  
Oğuzhan Yıldız ◽  
Mustafa Bayrak ◽  
Ali Celen ◽  
Ahmet Selim Dalkılıç ◽  
...  

Background: Researchers working in the field of nanofluid have done many studies on the thermophysical properties of nanofluids. Among these studies, the number of studies on specific heat are rather limited. In the study of the heat transfer performance of nanofluids, it is necessary to increase the number of specific heat studies, whose subject is one of the important thermophysical properties. Objective: The authors aimed to measure the specific heat values of Al2O3/water, Cu/water nanofluids and Al2O3-Cu/water hybrid nanofluids using the DTA method, and compare the results with those frequently used in the literature. In addition, this study focuses on the effect of temperature and volume concentration on specific heat. Method: The two-step method was used in the preparation of nanofluids. The pure water selected as the base fluid was mixed with the Al2O3 and Cu nanoparticles and Arabic Gum as the surfactant, firstly mixed in the magnetic stirrer for half an hour. It was then homogenized for 6 hours in the ultrasonic homogenizer. Results: After the experiments, the specific heat of nanofluids and hybrid nanofluid were compared and the temperature and volume concentration of specific heat were investigated. Then, the experimental results obtained for all three fluids were compared with the two frequently used correlations in the literature. Conclusion: Specific heat capacity increased with increasing temperature, and decreased with increasing volume concentration for three tested nanofluids. Cu/water has the lowest specific heat capacity among all tested fluids. Experimental specific heat capacity measurement results are compared by using the models developed by Pak and Cho and Xuan and Roetzel. According to experimental results, these correlations can predict experimental results within the range of ±1%.


Author(s):  
Chandrakant Sarode ◽  
Sachin Yeole ◽  
Ganesh Chaudhari ◽  
Govinda Waghulde ◽  
Gaurav Gupta

Aims: To develop an efficient protocol, which involves an elegant exploration of the catalytic potential of both the room temperature and surfactant ionic liquids towards the synthesis of biologically important derivatives of 2-aminothiazole. Objective: Specific heat capacity data as a function of temperature for the synthesized 2- aminothiazole derivatives has been advanced by exploring their thermal profiles. Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used systematically. Results: The present strategy could prove to be a useful general strategy for researchers working in the field of surfactants and surfactant based ionic liquids towards their exploration in organic synthesis. In addition to that, effect of electronic parameters on the melting temperature of the corresponding 2-aminothiazole has been demonstrated with the help of thermal analysis. Specific heat capacity data as a function of temperature for the synthesized 2-aminothiazole derivatives has also been reported. Conclusion: Melting behavior of the synthesized 2-aminothiazole derivatives is to be described on the basis of electronic effects with the help of thermal analysis. Additionally, the specific heat capacity data can be helpful to the chemists, those are engaged in chemical modelling as well as docking studies. Furthermore, the data also helps to determine valuable thermodynamic parameters such as entropy and enthalpy.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abayomi A. Akinwande ◽  
Adeolu A. Adediran ◽  
Oluwatosin A. Balogun ◽  
Oluwaseyi S. Olusoju ◽  
Olanrewaju S. Adesina

AbstractIn a bid to develop paper bricks as alternative masonry units, unmodified banana fibers (UMBF) and alkaline (1 Molar aqueous sodium hydroxide) modified banana fibers (AMBF), fine sand, and ordinary Portland cement were blended with waste paper pulp. The fibers were introduced in varying proportions of 0, 0.5, 1.0 1.5, 2.0, and 2.5 wt% (by weight of the pulp) and curing was done for 28 and 56 days. Properties such as water and moisture absorption, compressive, flexural, and splitting tensile strengths, thermal conductivity, and specific heat capacity were appraised. The outcome of the examinations carried out revealed that water absorption rose with fiber loading while AMBF reinforced samples absorbed lesser water volume than UMBF reinforced samples; a feat occasioned by alkaline treatment of banana fiber. Moisture absorption increased with paper bricks doped with UMBF, while in the case of AMBF-paper bricks, property value was noted to depreciate with increment in AMBF proportion. Fiber loading resulted in improvement of compressive, flexural, and splitting tensile strengths and it was noted that AMBF reinforced samples performed better. The result of the thermal test showed that incorporation of UMBF led to depreciation in thermal conductivity while AMBF infusion in the bricks initiated increment in value. Opposite behaviour was observed for specific heat capacity as UMBF enhanced heat capacity while AMBF led to depreciation. Experimental trend analysis carried out indicates that curing length and alkaline modification of fiber were effective in maximizing the properties of paperbricks for masonry construction.


Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 703
Author(s):  
Zhao Li ◽  
Liu Cui ◽  
Baorang Li ◽  
Xiaoze Du

The effects of SiO2 nanoparticles on the heat storage properties of Solar Salt (NaNO3-KNO3) are studied using experimental and molecular dynamics (MD) simulations. The experiment results show the specific heat capacity of the molten salt-based nanofluids is higher than that of the pure base salt. We focus on the inference regarding the possible mechanisms behind the enhancement of the specific heat capacity which are considered more acceptable by the majority of researchers, the energy and force in the system are analyzed by MD simulations. The results demonstrate that the higher specific heat capacity of the nanoparticle is not the reason leading to the heat storage enhancement. Additionally, the analysis of potential energy and system configuration shows that the other possible mechanisms (i.e., interfacial thermal resistance theory and compressed layer theory) are only superficial. The forces between the nanoparticle atoms and base salt ions construct the constraint of the base salt ions, further forms the interfacial thermal resistance, and the compressed layer around the nanoparticle. This constraint has a more stable state and requires more energy to deform it, leading to the improvement of the heat storage property of nanofluids. Our findings uncover the mechanisms of specific heat capacity enhancement and guide the preparation of molten salt-based nanofluids.


Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3222
Author(s):  
Kamil Goc ◽  
Janusz Przewoźnik ◽  
Katarzyna Witulska ◽  
Leszek Chlubny ◽  
Waldemar Tokarz ◽  
...  

A study of Ti3Al1−xSixC2 (x = 0 to x = 1) MAX-phase alloys is reported. The materials were obtained from mixtures of Ti3AlC2 and Ti3SiC2 powders with hot pressing sintering technique. They were characterised with X-ray diffraction, heat capacity, electrical resistivity, and magnetoresistance measurements. The results show a good quality crystal structure and metallic properties with high residual resistivity. The resistivity weakly varies with Si doping and shows a small, positive magnetoresistance effect. The magnetoresistance exhibits a quadratic dependence on the magnetic field, which indicates a dominant contribution from open electronic orbits. The Debye temperatures and Sommerfeld coefficient values derived from specific heat data show slight variations with Si content, with decreasing tendency for the former and an increase for the latter. Experimental results were supported by band structure calculations whose results are consistent with the experiment concerning specific heat, resistivity, and magnetoresistance measurements. In particular, they reveal that of the s-electrons at the Fermi level, those of Al and Si have prevailing density of states and, thus predominantly contribute to the metallic conductivity. This also shows that the high residual resistivity of the materials studied is an intrinsic effect, not due to defects of the crystal structure.


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