Evaluation of Quasi-Steady Theory Applied to Windborne Flat Plates in Uniform Flow

This paper analyzes models based on the quasi-steady theory for the flight of windborne plate debris. It is shown that the effects of the rotational lift, drag, and pitching moment are important and are included in the model. The model was used with success to predict the behavior of thin, square plates in a uniform stream, based on comparisons with existing experimental data. In fact, some of the scatter in the existing experimental data was explained by the numerical results. It was also shown that the buoyancy parameter was the key parameter in determining initial flight speeds and normalization of spatial coordinates with this parameter collapsed the data well.     

Rheological Properties and Emulsifying Activity of Gum Karaya (Sterculia Urens) in Aqueous System and Oil in Water Emulsion: Heat Treatment and Microwave Modification

Gum karaya is a polysaccharide gum from Sterculia urens tree. It is used as an emulsifier and thickening agent in cosmetics and pharmaceuticals. However, it has very strong swelling properties, high viscosity, and low solubility, providing the restricted applications in the food industry. The main objective of this study was to investigate the effects of different heat treatment and microwave variables (i.e., time: 8, 10, and 12 min; power: 700 and 1000 W) on the functional properties of gum karaya in the aqueous system and oil-in-water emulsion. In this regard, the rheological properties, emulsifying activity, average droplet size, and surface morphology of the native- and microwave-treated gums were analyzed and compared. Dynamic oscillatory test indicated that the microwave-treated gum karaya had more gel-like behavior than viscous-like behavior (G′ > G″) at a relatively high concentration (20% or 20 g/100 g). When gum karaya was treated by microwave for 8–12 min, both elastic (G′) and viscous (G″) moduli were declined. The native- and microwave-treated gum karaya exhibited a shear-thinning (pseudoplastic) behavior in the aqueous system and oil-in-water emulsion. The results showed that the microwave-treated gum karaya had smaller particles than the native gum in the aqueous system. On the other hand, the emulsion containing the microwave-treated gum karaya had finer emulsion droplets than the control containing the native gum karaya. This confirmed that the application of microwave treatment led to significantly (p < 0.05) improve the emulsifying activity of gum karaya.     

Effect of different drying methods on chemical and molecular structure of heteropolysaccharide–protein gum from durian seed

The functional properties and biological aspects of a natural biodegradable biopolymer depend on its chemical and molecular structure. In this study, the effect of different drying processes on the chemical and molecular structure of the natural biodegradable biopolymer from durian seed was investigated. The chemical structure was analyzed by assessing the carbohydrate profile, protein, amino acid composition, moisture, and ash. Molecular weight (M_w), number average molecular weight (M_n), M_w/M_n ratio and mass recovery were assessed by using a size-exclusion chromatography coupled to multi angle laser light-scattering (SEC-MALS). The present study revealed that main monosaccharides in the chemical structure of differently dried durian seed gums were galactose (50.1–64.9%), glucose (29.4–45.7%%), arabinose (0.11–0.89%), and xylose (0.019–0.86%). The protein analysis indicated the presence of a low amount of the protein fraction (3.2–3.9%) in the chemical structure of the biopolymer from durian seed. The most abundant amino acids in the chemical structure of durian seed gum were leucine (31.78–43.02%), lysine (6.23–7.78%), aspartic acid (6.45–8.58%), glycine (6.17–7.27%), glutamic acid (5.43–6.55%), alanine (4.60–6.23%), and valine (4.49–5.52). The current study exhibited that the biodegradable biopolymer from durian seed was a heteropolysaccharideprotein complex with medium M_w ranging from 1.06 × 10⁵ to 1.15 × 10⁵ (g/mol).     

Effects of Fat Replacers and Sweeteners on the Time-Dependent Rheological Characteristics and Emulsion Stability of Low-Calorie Pistachio Butter: A Response Surface Methodology

The effect of three fat replacers (xanthan gum, Reihan seed gum, and Balangu seed gum) and two sweeteners (sucrose and isomalt) on time-dependent rheological properties of low-calorie pistachio butter were analyzed using response surface methodology. The steady shear behavior of all samples was shear thinning (n = 0.156–0.6175), and power law model was fitted the upward and downward curves properly (R ² = 0.847–0.998). Balangu seed gum (0.01–0.04 wt.%), Reihan seed gum (0.01–0.023 wt.%), xanthan gum (0.06–0.1 wt.%), isomalt (0–1 wt.%), and sucrose (0.25–1 wt.%) were the levels investigated. A central composite design was used to develop models for the responses. The obtained experimental data were fitted to a second-order polynomial equation and also analyzed by appropriate statistical methods. In most cases, increasing the sweetener level led to a significant decrease in consistency coefficients. However, the effect on the flow behavior index was not significant. The effect of gum concentration on the rheological parameters was not significant (p ≤ 0.1), except for formulas prepared using Balangu seed gum. All formulas studied were stable on shelf.     

Diffractive element design for resonant scanner angular correction

We propose an optical corrective element with zooming capability to convert nonlinear sinusoidal scanning into linear scanning. Such a device will be useful for linearizing the angular scan of a resonant mirror scanner. The design methodology is to create a graded index of refraction device as the reference design, with its index of refraction parameters based on the propagation of an electromagnetic field in inhomogeneous media. The algorithm for converting this refractive element to the corresponding binary diffractive version is also presented. Design and simulation data are shown.     

A tiny EBG‐based structure multiband MIMO antenna with high isolation for LTE/WLAN and C/X bands applications

This article proposes a compact multiple‐input multiple‐output (MIMO) antenna with the electromagnetic band gap (EBG) structures for mobile terminals. The proposed MIMO antenna is composed of two radiation patches in which diagonal and folded microstrip lines are utilized to control the frequency bands. The radiation patch, one EBG structure and a rectangular‐shaped ground plane are etched on both sides of the antenna. The EBG structures have been employed for reducing the mutual coupling between the antenna elements. As a result of the effect of these structures, the mutual coupling between the two elements is reduced by less than ?30 dB. The proposed antenna is implemented on an FR4 substrate with dimensions 20 × 10 × 1 mm³. According to measured results, frequency ranges of 2.2 to 3.6 GHz and 5.1 to 5.9 GHz with S₁₁ < ?10 dB and also 3.7 to 5 GHz and 8 to 12 GHz with S₂₂ < ?10 dB have been obtained. Moreover, measured S₁₂ and S₂₁ with values of less than ?30 dB for both Ports have been realized. Additionally, the envelope correlation and radiation efficiency of the purposed antenna are less than 0.09 and more than 82%, respectively.