• Experimental and theoretical comparisons have been performed for natural convection heat transfer over rectangular fins array at different fin parameters. This investigation includes the effect of fin length, fin spacing, fin height, orientation angle, and temperature difference between the heat sink and the surrounding environment. To understand the general flow patterns dominating flows from the heat sink, the three dimensionless elliptic governing equations were solved using finite volume computational fluid dynamics (CFD) code, and the experimental work was carried for the system at different orientations. A new empirical correlation (modified of McAdam's correlation) was derived to correlate the mean Nusselt number as a function of the Rayleigh number. The average heat transfer coefficient has a maximum value at an orientation angle equal to zero degrees, and it decreases with an increasing orientation angle. The heat transfer rate per unit base area increases as fin spacing increase until it reaches a maximum value (6.5 mm), then it decreases with a further increase of fin spacing. The results of these investigations between the experimental and theoretical study were showing good agreements with similar international works.

This paper presents a new high-capacity algorithm for audio watermarking for the purpose of embedding a watermark audio signal into an original audio signal. This algorithm uses DCT (discrete cosine transform) in combination with SVD (singular value decomposition), DWT (discrete wavelet transform), and CZT (chirp ztransform). For the purpose of ensuring high levels of imperceptibility and robustness, a low-frequency sub band of 1-level DWT is selected to embed the watermark, followed by DCT, CZT, and SVD. As a result, the proposed algorithm achieves a high capacity of 352800 bits per second while a good quality audio signal is maintained (having an objective difference grade of more than-0.04). It also provides high imperceptibility (a signal to noise ratio of more than 58 dB) and it is extremely resistant to common audio attacks, including requantizing, resampling, additive white Gaussian noise or AWGN, MP3 compression, and low-pass filtering. The proposed algorithm presents much better compared to the audio watermarking algorithms already existent.

Andrographolide (AG) has been shown to have several medicinal and pharmaceutical effects, such as antimicrobial, anti-inflammatory, antioxidant, anti-diabetic, and anti-malarial activities. Moreover, studies to assess the pharmacological effect of AG on the metabolic changes of uninfected red blood cells (uRBCs) have not yet been investigated. This study aims to evaluate the pharmacological effects of AG compared to chloroquine (CQ) on the metabolic variations of uRBCs in vitro using a proton nuclear magnetic resonance (1H-NMR)-based metabolomics approach coupled with multivariate data analysis (MVDA). Forty-one metabolites were successfully identified by 1H-NMR. The results of the unsupervised data analysis principal component analysis (PCA) showed ideal differentiation between AG and CQ. PC1 and PC2 accounted for 71.4% and 17.7% of the explained variation, respectively, with a total variance of 89.10%. Based on S-plot and VIP values, a total of 28 and 32 metabolites were identified as biomarkers in uRBCs-AG and uRBCs-CQ, respectively. In uRBCs treated with AG, ten metabolic pathways were determined to be disturbed, including riboflavin metabolism, d-glutamate and d-glutamine metabolism, phenylalanine metabolism, glutathione metabolism, proline and arginine metabolism, arginine biosynthesis, citrate cycle, glycolysis/gluconeogenesis, and pyruvate metabolism as well as alanine, aspartate, and glutamate metabolism. In contrast, in CQ-treated uRBCs, nine affected metabolic pathways were determined, which involved the same metabolic pathways for uRBCs-AG, except for glutathione metabolism. These findings suggest an evident relationship between AG and CQ associated with metabolic changes in intact RBCs after being exposed to the treatment. The metabolomics results could allow useful comprehensive insights into the underlying mechanism of the action of AG and CQ on red blood cells. Consequently, the 1H-NMR-based metabolomics approach was successfully utilized to identify the pharmacological effects of AG and CQ on the metabolic variations of uRBCs.