scholarly journals Modelado matemático de secado solar de orégano (Plectranthus amboinicus) con tecnologías directas e indirectas

Author(s):  
Beatriz Castillo-Téllez ◽  
Margarita Castillo-Téllez ◽  
Erick César López-Vidaña ◽  
Gerardo Alberto Mejía-Pérez

Oregano is a plant with many nutritional and medicinal properties; there are also other applications in the chemical industry. In this work, the drying kinetics of oregano leaves are studied using a cabinet-type dryer with and without a forced convention, open sun drying, and indirect solar drying. The samples had an initial moisture content of 80 % and the final content of 9 %. The results indicate that indirect solar drying provides better control of operating conditions and greater protection against temperature effects, producing better quality in the dry product. The time required to reach the equilibrium moisture content in all experiments ranged from 375 to 600 min. The data were also adjusted to various mathematical models, resulting In Weibull, Logarithmic, and Page, which best represent the drying behavior of oregano leaves. The statistics used for indirect solar dryer are R2 of 0.9969, 0.9968, and 0.9945, X2 of 0.0363, 0.0363 and 0.0599 respectively.

Adjustable Multi glazing solar drying system is designed and fabricated for experimental study. The arrangement is made in the present model such that it can be wok as a single glazing, double glazing and multi-glazing solar dryer by adjusting the plain window glass (Glazing). The performance analysis and comparison of Single glazing (SGSD), double glazing (DGSD) and Triple pass solar drying system (TPSD) have been conducted by using red chilli. The performance curves show the effect of solar intensity on the collector efficiency, drying efficiency and pick-up efficiency of solar drying system. The collector efficiency of TPSD increased by 28.8% and 53% as compared to DGSD & SGSD respectively at average value of solar radiation 674.4 W/m² at 26.90 gm per second of air mass. The initial moisture content in red chili was measured and found 78.8 (wb) reduced to minimum moisture content 9.8% (wb). It could be concluded that, the time required to dry the red chilli in TPSD is minimum as compared to SGSD and DGSD.


1976 ◽  
Vol 39 (4) ◽  
pp. 244-245 ◽  
Author(s):  
G. BEETNER ◽  
T. TSAO ◽  
A. FREY ◽  
K. LORENZ

Triticale kernels were extruded using a Brabender Plasticorder extruder with ¾-inch rifled barrel and 1:1 flight depth ratio screw. Whole grain samples were extruded at initial moisture contents of 15, 20, and 25%. Debranned samples were extruded at an initial moisture content of 22%. Barrel temperatures of 350, 400, and 450 F and nozzle openings of 1/8 inch and 1/16 inch were used. The products were analyzed for thiamine and riboflavin content. Results were corrected for final moisture content and expressed as fraction retained. A multiple regression was done to determine the relationship between independent and derived variables, and the retention. Riboflavin retention was correlated simply as a function of barrel temperature. Thiamine retention of the debranned material was correlated as a function of nozzle size and barrel temperature. Thiamine retention of the whole grain samples was correlated for nozzle size, first and second order temperature effects, and confounding between nozzle size and temperature.


2013 ◽  
Vol 807-809 ◽  
pp. 478-485 ◽  
Author(s):  
Ting Li ◽  
Wen Yi Dong ◽  
Hong Jie Wang ◽  
Jin Nan Lin ◽  
Feng Ouyang ◽  
...  

In this study, the effect of operating parameters and the co-existing ions on the phosphate removal during the ferrous iron oxidation was investigated. Results showed that with the increase of DO and [Fe (II)]0, the final phosphate removal rate both increased. But with increasing of pH, the final phosphate removal rate firstly increased and then decreased when the pH was higher than 8.0. The co-existing ions affected the final removal rate significantly, and the kinetics of phosphate removal followed the pseudo-first-order kinetic model. The corresponding kobs trends for the cation followed the order of Cu2+>Mn2+>Zn2+>NH4+-N. The presence of Cu2+ promoted the phosphate removal significantly. Compared with the control, , the time required to achieve 40 % phosphate removal rate, at the condition of 0.5 mg/L Cu2+, reduced from 60 min to 10 s. However, the selective anions inhibited the phosphate removal, due to the formation of Fe-anions complexes. The effect of selective anions on the phosphate removal rate constant decreased in the order of SO42->Cl-> NO3-.


2018 ◽  
Vol 7 (1) ◽  
pp. 120
Author(s):  
Gusti Bagus Alit Budi Artawan ◽  
I Wayan Tika ◽  
I N. Sucipta

This research was conducted to know the difference of irrigation water requirement in the preparation of land using chisel plow and rotary plow. The variables observed in this study include: solum volume, soil porosity, initial moisture content of the soil, water requirements for inundation, puddle volume, and duration of soil tillage. Location used as sample of paddy field as much as 15 point sample for each plow which is grouped into three locations that is at upstream, middle, and downstream. At each location five rice samples were taken for each plow treatment. The volume of solum on the treated rice field using the chisel plow of 2122.00 m3 / ha while the volume of solum using rotary plow of 2096.33 m3 / ha. The initial soil moisture content in paddy field used as sample for chisel plow is 52,98% while rotary plow is 45,63%. The water requirement for the saturation of paddy field that is processed by rotary plow is bigger than the chisel plow is 505.97 m3 / ha, whereas in the chisel plow is 377,11 m3 / ha. The volume of inundation in the rotary plow is greater than the chisel plow rotary plow of 401.33 m3 / ha and chisel plow of 141.00 m3 / ha. For the length of time required to cultivate the soil, the chisel plow takes longer time of 29.69 hours / ha, while the rotary plow takes 14.35 hours / ha. The results of this study indicate that the processing of soil using plows of chisel requires less water than the rotary plow. In the processing of the soil using the plot of water chisel required is 5.07 l / dt , while for the rotary plow requires water as much as 17.69 l / dt .   Keywords: irrigation water requirement, soil tillage, chisel plow, rotary plow.


Author(s):  
Sajeev Rattan Sharma ◽  
Sadhna Arora ◽  
Tarsem Chand

The thin layer drying of pretreated wild pomegranate seeds was conducted in a laboratory mechanical dryer at air temperatures of 55, 60 and 65°C. Six different mathematical models were used to predict the drying behavior. Thompson model was adjudged as the best model. The coefficients of this model were found to be correlated best with drying temperatures by using two degree polynomials. The effective diffusivity was determined to be 3.18 x 10-10 to 4.36 x 10-10 m2/s. The activation energy for diffusion was found to be 29.07 kJ /mol. The variation in shrinkage exhibited a linear relationship with moisture content. The rate constants for “a” and “b” parameters of colour were determined and their value was 0.0128 and 0.0136 min-1, respectively.


2016 ◽  
Vol 12 (2) ◽  
Author(s):  
Hosain Darvishi ◽  
Zanyar Farhudi ◽  
Nasser Behroozi-Khazaei

Abstract Moisture diffusivity (Dem), mass transfer coefficient (hm), activation energy and drying kinetics of the dill leaves were studied and modeled as a function of temperature (40–70 °C) and moisture content (0.20–5.67 kg water/kg dry matter). Results showed that the Dem and hm significantly depend on the temperature and moisture content (p < 0.05). The average of Dem and hm varied between 4.02 × 10–9 to 9.65 × 10–9 m2/s, and 2.38 × 10–7 to 6.33 × 10–7 m/s, respectively. Activation energy showed a significant dependence on the moisture content and estimated as 16.84 kJ/mol for diffusion model and 28.70 kJ/mol for mass transfer model. Out of the six models considered, the logarithmic model showed the best fit to drying behavior of the dill leaves.


Author(s):  
N. A. Nata ◽  
F. Mohd Said ◽  
S. Md Shaarani@Md Nawi ◽  
N. Harun

Lovastatin is a potent drug for lowering the blood cholesterol. It is a competitive inhibitor of 3-hyroxy3-methyl glutaryl coenzyme A (HMG-CoA) reductase, which is a key enzyme in the cholesterol production pathway. Lovastatin increases the good cholesterol or high-density lipoproteins to prevent the formation of plaque inside the blood vessels. This study aims to develop a process model of lovastatin production, produced by Monascus purpureus under solid-state fermentation using oil palm frond. SuperPro Design V9.5 software was used to develop and simulate the process model. Three parameters which are initial moisture content, composition of peptone and potassium, were varied to investigate their effects on lovastatin production. The optimum condition simulated using the process model at pH 7 with 60% initial moisture content, 0.0075 kg/hr of potassium, and 0.0075 kg/hr of peptone was able to produce 0.0288 kg/kg of lovastatin. The simulated results show good agreement with experimental work, with low percentage error of 5.77%, and provide a good approximation on the production of lovastatin under various process operating conditions.


2020 ◽  
Vol 13 (2) ◽  
pp. 94-102
Author(s):  
Hada Masayu I ◽  
A Fauziah ◽  
K Y Pin ◽  
Safwan K Ihsan ◽  
M Shalini ◽  
...  

The effect of drying temperature on the leaves of Vitex negundo was determined. Three levels of temperatures (40, 50 and 60°C) were used in the presented study. The initial moisture content of the leaves was 69.98%. Continuous drying at the above mentioned temperature levels was conducted to determine the drying time required to achieve equilibrium moisture content. The quality of dried leaves was evaluated based on the quantity of agnuside, a major compound in V. negundo using HPLC analysis. The fastest drying of the leaves was achieved at 60°C, followed by at 50°C, but HPLC results showed that dried V. negundo suffered at 40% reduction in agnuside content when drying at 60°C as compared to at 40°C. Slight reduction of agnuside was found in the sample dried at 50°C as compared to at 40°C. Whereas, antioxidant results showed that V. negundo leaves have significant level of phenolic content and the effect of drying at higher temperature has significantly reduce the amount of phenolics in V. negundo leaves. Total phenolic content of V. negundo leaves was highest at 50 °C drying temperature. Based on the findings of this work, the best convection oven drying condition for V. negundo leaves was at 50°C with the highest agnuside concentration of 502.224 mg/L and phenolic content of 286.7 ± 11.0 mg GAE/100g.


2012 ◽  
Vol 12 (55) ◽  
pp. 6835-6852
Author(s):  
DG Mercer ◽  

Mangoes are under-utilized fruits that grow naturally in many sub-Saharan African countries. At the present time most mangoes are sold fresh in local markets. There is little done to preserve them for use during the off-season. Drying is one way in which the economic potential of mangoes could be exploited. This study was undertaken to investigate and compare the kinetics of mango drying using three basic drying methods: open-air drying on wire mesh racks; solar drying in a prototype dryer equipped with solar-powered exhaust fans; and forced-air drying in an Armfield Model UOP8 laboratory-scale tray dryer. Results could then be used to determine appropriate drying techniques for mango processing in sub-Saharan Africa on both local and commercial scales. Of these methods, forced air drying was found to provide the best overall results, based on water removal rates and general control over the drying process. Solar drying, while viewed as a promising technology for application in developing countries, was considerably slower than forced- air drying and is severely restricted by climatic conditions. A similar situation was observed for open-air drying, which was the slowest drying method of the three. Based upon mathematical models developed for each drying method, 11.6 hours was predicted as being required for mangoes in the forced-air dryer to a final moisture content of 10% (wet basis). Sixteen (16) hours and 24 hours of exposure to appropriate drying conditions were predicted as being required for solar drying and open-air drying, respectively. This could take three or four days to achieve under actual operating conditions. These times were supported by experimentally determined values. The impact of air temperature and linear air velocity on the drying kinetics of sliced mangoes were also investigated using the forced-air dryer. A linear velocity of 0.5 m/s was found to be sufficient for satisfactory drying of the mango slices when combined with an air temperature in the range of 50ΕC to 60ΕC. It is recommended that forced-air drying be utilized whenever possible for the drying of mango slices for both food safety and food quality reasons.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
S. Syahrul ◽  
M. Mirmanto ◽  
S. Romdani ◽  
S. Sukmawaty

Grain processing does not meet the actual grain harvests. This is due to the unsuitable drying process. Milling grain entrepreneurs and farmers in Indonesia are currently conducting a drying process under the sun. Based on the National Standards Body (BSN), grain moisture content must be at 14% to maintain the grain at high qualities. The purpose of this study is to determine the effect of velocity and grain mass variations on drying times. The grain used in this study contains an initial moisture content of 22% ± 0.5%. The grain is dried by inserting it into the drying chamber and varying the air velocities and grain mass. The air velocities used are 4 m/s, 5 m/s, 6 m/s and the variations of the grain mass are 1 kg 2 kg and 3 kg. The results show that increasing the air velocity decreases the drying time. On the other hand, when the grain mass is increased, the drying time elevates. The air velocity and mass of the grain that results in the fastest drying time are 6 m/s and 2 kg. The time required for achieving the water content of 13.6% is 30 menit. At the air velocity of 4 m/s, and the grain masses of 1 kg, 2 kg, and 3 kg, to achieve moisture contents of 13.4%, 13.5% and 13.4% the drying time needs 50 minutes.


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