Numerical and Physical Modeling of the Effect of Roughness Height on Cavitation Index in Chute Spillways

© 2019, Iran University of Science and Technology. This study presents the results of physical and numerical modeling of the effect of bed roughness height of chute spillways on the cavitation index. A 1:50-scale physical hydraulic model of the chute spillway of Surk Dam was constructed at the hydraulic laboratory of Shahrekord University, Iran. The experiments were conducted for different flow rates and the parameters of pressure, velocity, and flow depth in 26 positions along the chute. Finally, the ANSYS-FLUENT model was calibrated in the chute spillway using the experimental data by assumptions of two-phase volume of fluid and k–ε (RNG) turbulence models. The cavitation index in different sections of the chute spillway was calculated for different values of bed roughness including the roughness heights of 1, 2, and 2.5 mm. Results showed that the minimum values of the cavitation index were 0.2906, 0.2733, and 0.2471 for the roughness heights of 1, 2, and 2.5 mm, respectively. The statistical significance analysis showed that reducing the roughness height from 2.5 to 1 mm would not change significantly the value of the cavitation index at 95% confidence interval

Fabrication and characterization of a pH-sensitive intelligent film incorporating dragon fruit skin extract

A novel intelligent pH-sensing indicator based on gelatin film and anthocyanin extracted from dragon fruit skin (Hylocereus polyrhizus) (DFSE) as a natural dye was developed to monitor food freshness by the casting method. Anthocyanin content of DFSE was 15.66 ± 1.59 mg/L. Dragon fruit bovine gelatin films were characterized by Fourier transform infrared spectroscopy (FTIR) and observed by a scanning electron microscope (SEM). Moisture content, mechanical properties, water solubility, water vapor permeability (WVP), light transmittance, color, and pH-sensing evaluations were evaluated for potential application. FTIR spectroscopy revealed that the extracted anthocyanin could interact with the other film components through hydrogen bonds. When the extract was added, films showed a smooth and clear surface as observed by SEM. The addition of anthocyanin increased the moisture content, thickness, and water solubility of the films, but decreased the WVP and light transmittance of films. Also, the incorporation of 15% v/v DFSE decreased the tensile strength from 17.04 to 12.91 MPa, increasing the elongation at break from 91.19% to 107.86%. The films showed higher ΔE with increasing DFSE content, which indicated that the film had good color variability. A significant difference in the color of the films was observed with exposure to different pH buffer solutions. The findings demonstrated that gelatin film incorporated with DFSE could be used as a visual indicator of pH variations to monitor the freshness of foods during storage time

A Generalization of Otsu's Method and Minimum Error Thresholding

We present Generalized Histogram Thresholding (GHT), a simple, fast, and effective technique for histogram-based image thresholding. GHT works by performing approximate maximum a posteriori estimation of a mixture of Gaussians with appropriate priors. We demonstrate that GHT subsumes three classic thresholding techniques as special cases: Otsu's method, Minimum Error Thresholding (MET), and weighted percentile thresholding. GHT thereby enables the continuous interpolation between those three algorithms, which allows thresholding accuracy to be improved significantly. GHT also provides a clarifying interpretation of the common practice of coarsening a histogram's bin width during thresholding. We show that GHT outperforms or matches the performance of all algorithms on a recent challenge for handwritten document image binarization (including deep neural networks trained to produce per-pixel binarizations), and can be implemented in a dozen lines of code or as a trivial modification to Otsu's method or MET.Comment: ECCV 202

Application of Starch Foams Containing Plant Essential Oils to Prevent Mold Growth and Improve Shelf Life of Packaged Bread

In the recent years, considerable attention has been allocated in the area of using natural preservatives in foods, especially vegetable oils.  Starch foams prepared from high amylose starch are useful for encapsulation of substances such as chemicals, liquids or solids, including flavor compounds, pharmaceuticals and essential oils. The foams have the ability to trap the active material and subsequently release the activity. Cinnamon oil is absorbed to foam starch microparticles and acts as an antimicrobial agent. This study was designed and implemented to evaluate the use of starch foam containing vegetable oil to prevent mold growth and improve packaged bread shelf life. For this purpose, first cinnamon essential oil was extracted with water by distillation method then, 250 groups of bread were prepared within polypropylene plastic bags. Various amounts of cinnamon essential oil (500, 750, 1000and1500ppm) with 1 g of starch foam powder inside sterilized filter paper were added to these packages.The obtained results of multi-way and intergroup repeated tests indicated that there was a significant difference (P <0/05) between the control groups and various groups containing cinnamon essential oil in terms of microbial load. In the groups containing essential oils, less increase was showed in microbial load and with increasing concentrations of cinnamon essential oil, mold and yeast growth rate decreased. It concluded that by using starch foam containing cinnamon essential oil in bulky bread packing at ambient temperature (25°C), the spoilage process of bulky bread can be postponed 3 to 6 days, and it can be used as an appropriate natural and antifungal preservative in packaging of bread

Subjective and objective quality assessment of degraded document images

The huge amount of degraded documents stored in libraries and archives around the world needs automatic procedures of enhancement, classification, transliteration, etc. While high-quality images of these documents are in general easy to be captured, the amount of damage these documents contain before imaging is unknown. It is highly desirable to measure the severity of degradation that each document image contains. The degradation assessment can be used in tuning parameters of processing algorithms, selecting the proper algorithm, finding damaged or exceptional documents, among other applications. In this paper, the first dataset of degraded document images along with the human opinion scores for each document image is introduced in order to evaluate the image quality assessment metrics on historical document images. In this research, human judgments on the overall quality of the document image are used instead of the previously used OCR performance. Also, we propose an objective no reference quality metric based on the statistics of the mean subtracted contrast normalized (MSCN) coefficients computed from segmented layers of each document image. The segmentation into four layers of foreground and background is done on the basis of an analysis of the log-Gabor filters. This segmentation is based on the assumption that the sensitivity of the human visual system (HVS) is different at the locations of text and non-text. Experimental results show that the proposed metric has comparable or better performance than the state-of-the-art metrics, while it has a moderate complexity. The developed dataset as well as the Matlab source code of the proposed metric is available at http://www.synchromedia.ca/system/files/VDIQA.zip. - 2017 Elsevier Masson SASThis publication was made possible by NPRP grant NPRP 7-442-1-082 from the Qatar National Research Fund (a member of Qatar Foundation). The statements are solely the responsibility of the authors.Scopu

Fabrication of cassava starch/mentha piperita essential oil biodegradable film with enhanced antibacterial properties

In this study, an edible film is prepared using Mentha piperita essential oil (MPEO) plasticized by sorbitol and glycerol in cassava starch matrix by the solution intercalation process. The effects of MPEO addition on the color, and antimicrobial activity (Staphylococcus aureus and Escherichia coli), as well as the barrier properties of active films were investigated. MPEO was incorporated into cassava starch biodegradable films at different level (1-3%, w/w). A low level of MPEO can obviously increased the water vapor permeability (WVP) of cassava starch/MPEO films. When the MPEO contents varied from 0-3% w/w, the lightness (L*value) decreased from 95.63 to 89.17 while the a* value increased from 0.15 to 0.82. The cassava film showed antimicrobial properties against S. aureus and E.coli by using agar diffusion method. These findings showed that Mentha piperita essential oil has a good potential to be added to cassava to make antimicrobial coating or film for food and non-food packaging