Study of Continuous and Intermittent Drying of Pear Through Mathematical and Diffusion Models

The methods for drying agricultural products are necessary to check the quality of the final product and feasibility of the process. The objective of this study was to perform the drying of pear by continuous and intermittent methods (α = 2/3) at two different temperatures, compare the two methods and describe the processes using mathematical and diffusion models to evaluate the saving of time and effective processing energy. For continuous drying, Page model was the one which best fitted to the experimental data, with highest coefficient of determination and lowest chi-square. Regarding intermittent drying Page model was also the one which best fitted to the experimental data for the two temperatures studied. When comparing the drying methods studied, it was found that intermittent drying produced a similar and considerably better effect on the energy saving aspect, compared with continuous drying: 41.7% at 50 °C and 25.8% at 70 °C. The effect of time intervals with the product out of the dryer, during the intermittent drying process, was reflected in the increase in the diffusion coefficient, so that the transport of moisture occurred more quickly for this type of drying, which contributes to justify the reduction of effective operating time and increased dry product quality.

Pengembangan website berbasis blended learning dengan materi bangun ruang sisi lengkung kelas IX SMP

Dunia pendidikan pada saat ini telah berada pada abad pengetahuan (abad 21). Salah satu unsur pembelajaran abad 21 yaitu menekankan pada pengembangan keterampilan belajar. Pengembangan keterampilan terkait informasi dan komunikasi salah satunya dapat guru ciptakan dengan mengembangkan pembelajaran berbasis blended learning. Website berbasis blended learning dengan materi bangun ruang sisi lengkung kelas IX SMP menggunakan perangkat open source moodle versi 2.2. Materi bangun ruang sisi lengkung ditampilkan dalam bentuk web page. Model pengembangan yang digunakan dalam penelitian ini adalah pengembangan Thiagarajan (4D) yang terdiri dari: define, design, develop, dan dissiminate, tetapi tanpa tahap dissiminate. Berdasarkan hasil angket validasi tersebut dapat disimpulkan bahwa website berbasis blended learning dengan materi bangun ruang sisi lengkung kelas IX SMP termasuk kriteria valid/ layak digunakan sebagai alternatif website dalam pembelajaran matematika.

Dried salted anchovy different processing methods: drying kinetics and modelling

Dried salted anchovy is processed with a combination of the salting and drying processes. Methods of salting and drying will determine the characteristics of the end product. The process of salting can be done by soaking (S) or boiling (B) in brine and drying can be done by mechanical drying (MD) or electric oven (OD). This study is aimed to determine the drying kinetics and mathematical models of dried salted anchovy processed with boiled salting and drying in the mechanical dryer (BMD), soaked salting and drying in the mechanical dryer (SMD) and boiled salting and drying in the oven (BOD). In the soaking treatment, fresh anchovy was soaked in 5% brine for 30 mins, while in boiling treatment, anchovy boiled in 5% brine for 10 mins. After the salting process was done, the anchovy was dried at 40°C for 3 hrs. The result has shown that BMD gives the highest drying constant. The page model is more suitable than other mathematical models because it has the highest R2 and the lowest SEE (Standard Error Estimates) value. The result of the effective diffusivity of BMD, SMD and BOD are 1.28067×10-10, 2.46685×10-10 , 1.80245×10-10. This research will contribute to the improvement of the drying and salting method to achieve a better quality of dried salted anchovies.

Drying Kinetics of Maize Cob Using Mathematical Modelling

Maize cobs (with husk and without husk) with initial moisture content of 78.38 % and 62.39 % (d.b.), respectively, were dried up to 20 % moisture content (d.b.) at three temperatures (45°C, 55°C and 65°C). Moisture ratios (MR) were calculated from moisture loss data and fitted to six (Newton’s, Page, Thompson, Modified Page, Henderson and Pabis, and Wang and Singh) drying mathematical models. Coefficient of determination (R2) and root mean square error (RMSE) were used for comparison of the models. From the analyses, Modified Page model showed the best fit to the experimental data with R2 varying from 0.9924 to 0.9968 for maize cob with husk and 0.9994 to 9989 for cobs without husk at given drying temperatures. The Modified Page model was found to be a superior model representing the drying kinetics of maize cob with and without husk at drying temperatures of 45, 55, and 65°C. The increase in drying temperature caused a reduction in drying time, and the drying took place in the falling rate period. Maize cobs with husk took more time for drying as compared to that without husk at the same temperature. The values of effective diffusivity lied between 1.079×10-8 m2.s-1 and 4.239×10-8 m2.s-1 for maize cob with husk, and between 1.194×10-8 m2.s-1 and 5.230×10-8 m2.s-1 for maize cob without husk. Effective diffusivity increased with an increase in drying temperature and was higher for maize cob without husk than that of with husk

Evaluation of Novel Portable Passive and Cabinet Solar Dryers in Sun Drying of Mint Leaves under Indiana Weather Conditions

HighlightsThe Page model best predicted the drying rates of mint leaves in thin-layer laboratory experiments under cyclical temperature change and in field experiments using open-air sun drying and Dehytray and Dehymeleon solar dryers.The total time for drying mint leaves with all solar drying methods was the same (48 h).For all drying methods, the aerobic bacterial count was significantly less on dried mint leaves than on fresh leaves.Color change was less impacted by sunlight with the Dehymeleon than with the Dehytray and open-air sun drying.Abstract. The drying kinetics and quality attributes of mint leaves (Mentha spitaca) were studied to determine the drying performance of two solar drying technologies (Dehymeleon V.2 and Dehytray) and their effect on dried mint quality. Field drying experiments were carried out under weather conditions at Purdue University, West Lafayette, Indiana. Thin-layer laboratory drying experiments were conducted for whole mint leaves at three temperatures [24°C (75°F), 35°C (95°F), and 54°C (130°F)] and airflow velocity of 1 m s-1 to determine the drying kinetics for the diurnal cycles typical for solar drying. The Page model was the most suitable model to predict the drying behavior of mint leaves for both the lab and field experiments. Even though the drying rate was higher with open-air sun drying on uncovered Dehytrays than with covered Dehytrays and the Dehymeleon, the total drying time for all methods was the same (48 h). Color change in mint leaves was less impacted by sunlight for mint leaves dried using the Dehymeleon, while the Dehytray and open-air sun drying had similar results due to their exposure to direct sunlight. For all drying methods, the aerobic bacterial count was significantly less for dried mint leaves than for fresh mint leaves. The log reductions in aerobic bacterial count achieved with open-air sun drying, Dehymeleon, and Dehytray were 0.47, 2.3, and 0.40, respectively. Keywords: Diffusion, Drying kinetics, Food quality, Mint leaves, Solar drying, Sun drying, Thin-layer drying.

Pengembanagn Model E-Learning Adaptif untuk Materi Pembelajaran Jaringan Komputer pada Amik Almuslim

Abstrak: Perkembangan teknologi e-learning sudah sangat pesat, hal ini ditandai dengan munculnya sejumlah perangkat lunak seperti: moodle, Atutor, LRN, Dukeos dan lain sebagainya, disisi lain adanya keterbatasan e-learning dapat menghambat kemajuan proses pembelajaran, dimana hambatan yang muncul adalah dalam mengoperasionalkan proses pembelajaran dan proses kognitif mahasiswa. Sistem e-learning adaptif dikembangkan atas asumsi bahwa model pembelajaran individual mampu memberikan hasil yang lebih baik dari pada model pembelajaran lainnya. Digunakan Jaringan Bayesian dalam menentukan model pengguna dan dipilih Model Gaya Belajar Dunn & Dunn untuk menentukan ke-adaptif-an sebuah e-learning. Dalam pengembangan aplikasi digunakan model pengembangan perangkat lunak sequencial linear, tahap analisa digunakan Unifed Modelling Language (UML), seperti : Use Case Diagram, Activity Diagram dan Deployment Diagram, sedangkan tahap pemberian kodenya menggunakan PHP. Penentuan model pengguna dengan Jaringan Bayesian ditetapkan 4 parameter, yaitu : Persepsi kemudahan penggunaan (C1), Motivasi (C2), Sikap dalam penggunaan (C3) dan Penerimaan terhadap e-learning (C4). Hasil dari perhitungan terhadap paramater-parameter ini mengarah ke model gaya belajar Dunn & Dunn yang mendasarkan kepada kesamaan fungsionalnya. Hasil dari analisa dihasilkan 9 page dalam mendukung tercapainya e-learning adaptif ini, dimana ada 3 page utama, yaitu : page model perkuliahan berbasis teks, page model perkuliahan berbasis visual & suara dan page model perkuliahan berbasis image & teks yang dapat menjadi pilihan mahasiswa dalam belajar. Pengujian untuk sistem ini dilakukan dengan menggunakan Blackbox Testing bertipe Functional Testing. Penelitian ini telah berhasil memodelkan e-learning adaptif dengan menentukan model pengguna menggunakan Jaringan Bayesian dan model Dunn & Dunn untuk model gaya belajar mahasiswa. Pengembangan e-learning adaptif ini perlu dilakukan penelitian lebih lanjut dengan berbagai model gaya belajar seperti : Felder Silverman atau Kolb. Kata kunci: e-learning adaptive, style learning.

Mathematical Modelling of Blanch-Assisted Drying of Pomegranate (Punica granatum) Arils in a Hot-Air Drier

The effect of blanching conditions on the hot-air drying kinetics of three pomegranates (cvs. “Acco”, “Herskawitz” and “Wonderful”) were assessed. Water blanching conditions considered were 90 °C for 30 s, 90 °C for 60 s, 100 °C for 30 s and 100 °C for 60 s. The drying experiments were carried out at 60 °C, 19.6% relative humidity and at a constant air velocity of 1.0 m s−1. The experimental curves were fitted to seven different drying models. For the Acco cultivar, the drying behaviour was best predicted by the Logarithmic and Page model for blanched (R2 ranging between 0.9966 and 0.9989) and unblanched (R2 = 0.9918) samples, respectively. Furthermore, for the Herskawitz cultivar, Logarithm, Page and Midili models were most suitable for predicting drying behaviour of both blanched and unblanched samples. Also, for the Wonderful cultivar, Logarithm and Midili models were most accurate for predicting the drying behaviour for both blanched and unblanched samples amongst other models. The blanched samples dried faster with shorter drying times: “Acco” (7 h), “Herskawitz” (8 h), and “Wonderful” (7 h), compared to the unblanched samples, which dried after 15, 20 and 11 h, respectively. Effective diffusion coefficient of moisture in pomegranate arils ranged from 4.81 × 10−9 and 1.11 × 10−8 m2 s−1 for the Acco cultivar, for the Herskawitz cultivar; 3.29 × 10−9 and 1.01 × 10−8 m2 s−1 and for the Wonderful cultivar; 5.83 × 10−9 and 1.09 × 10−8 m2 s−1. Overall, blanching resulted in low energy consumption during drying of pomegranate arils. In addition, the Logarithmic model generally showed an appropriate model for blanched samples regardless of cultivar. For unblanched samples, the Page model was more appropriate for “Acco” and “Herskawitz”, while the Midili model was appropriate for “Wonderful”. Therefore, this study provided science-based and practical drying conditions for the investigated pomegranate cultivars.

Mathematical Modelling, Moisture Transport, Shrinkage and Nutrient Content Properties in Drying Selected African Leafy Vegetables

HighlightsPage model best described their drying pattern at moisture content above 0.5 w.b.Shrinkage linearly correlates to moisture loss.Activation energy correlates to air temperature.Vitamins A, C, and E are preserved by drying and storage. ABSTRACT. The study investigated physical, thermodynamic, and nutritional properties with drying and storage of selected African green leafy vegetables. The vegetables studied were: (Jute Mallow), (Slender Leaf), (Cowpea), (Nightshade), and (Amaranthus). Drying experiment was done at 30°C, 40°C, and 50°C in a convective laboratory dryer and drying was pattern fitted to existing models, moisture diffusivity, and activation energy trends were determined, shrinkage was determined from change in leaf thickness, and vitamins A, C, and E were analyzed using spectroscopy and high-pressure liquid chromatography as freshly harvested and after drying at 40°C and storage for 60 days. Results showed that drying occurred in the falling rate period and Page model could simulate the drying pattern of the vegetables with a ˜97% correlation between the empirical and predicted values with the model prediction being precise above 0.5 moisture content on wet basis (w.b.). Shrinkage was found to be a function of moisture loss at a range of 89% to 98% linear correlation. The rate of moisture loss and activation energy correlated with air temperature. The trend in the drying characteristics and moisture transport of the vegetables was unique with each vegetable. Drying at 40°C and storage for 60 days realized a retention in the scale range of 50% to 75% for vitamins A, C, and E. The study showed that drying is an effective way to preserve the vegetables. Keywords: Mathematical modeling, Mass transfer, Nutrient preservation, Shrinkage, Thermodynamic properties.

Drying kinetics of passion fruit peel for tea products

An important step in the development of passion fruit tea products is the drying procedure. This procedure uses a lot of energy. The optimization of drying needs knowledge of the drying kinetics. This paper focuses the development of drying kinetics for passion fruit peel. The experiments were conducted utilizing a thin layer dryer with drying air temperatures in the range of 45°C to 65°C The drying air velocity was constant at 1 m/s. The passion fruit peel were dried from their initial moisture content of 559±16% db to a final moisture content of 50±1% db. The models for the kinetic drying proposed by the authors are the Newton model, Page model and the Logarithmic model. The parameters for the drying kinetic models were found by curve fitting the experimental data using non-linear regression. The criteria for evaluating the models were the coefficient of determination (R2), a root mean square error (RMSE) and a reduced chi- square (x2). It was found that the drying kinetic model for passion fruit peel which gave the best fit was the Page model. This drying kinetic model can be applied to find optimum drying conditions.