Influence of Temperature and Air Velocity on Drying Time and Quality Parameters of Pistachio (Pistacia vera L.)

Abstract

Drying is one of the important steps in pistachio processing. In this step kernel moisture content is decreased from 50 to less than 5% (d.b.) which will result in suitable condition for storage. Study of effective parameters in pistachio drying is important since these parameters influence drying time and kernel quality. In this research, a mono layer of pistachios was dried at three different temperatures (60, 75, and 90°C), and three levels of drying air velocity (1.5, 2, and 2.5 m/s). Changes of drying time, protein, fat and peroxide value were investigated for two common Iranian pistachio varieties Kalehghouchi and Fandoghi. Sensory tests were also used to check flavor of pistachios dried at the three temperature levels (60, 75, and 90°C). Statistical analysis of the data indicated that increasing the temperature to 90°C reduced drying time down by about 37% and caused a change in pistachio flavour. Taste tests indicated a consumer preference for pistachios dried at 75°C. If the air velocity is increased from 1.5 to 2.5 m/s, drying time reduces about 10 percent. Changes in temperature and air velocity have no significant effects on protein and fat content of pistachios, but if temperature reaches 90°C, peroxide value will increase to 0.55 meq/kg, which is still within the permissible limit for processed pistachios.     

Multivariate Optimization and Adsorption Characterization of As(III) by Using Fraxinus Tree Leaves

This study introduces Fraxinus tree leaves as a new, efficient biosorbent of As(III). A suitable response surface was achieved by running a central composite design. Simultaneous optimization of both responses (R% and q) was carried out and 67% of the goal of desirability function was attained. The results obtained for simultaneous optimization are R = 70% and q = 80.6 mg g^?1 with 67% desirability in m = 600 mg L^?1 where s = 0.10 g and pH = 3.9. Langmuir and Freundlich isotherms model were applied in explaining the sorbent–sorbate equilibrium study, and maximum capacity uptake equals 99.97 mg g^?1 and K_L = 0.05 L mg^?1 has been obtained. Fourier Transfer Infra-Red (FT-IR) and kinetic results were considered to examine the functional groups involved and the adsorption mechanism.     

Intracycle RPM control for vertical axis wind turbines

The wind energy market is currently dominated by horizontal axis wind turbines (HAWTs); however, vertical axis wind turbines (VAWTs) are emerging as a design alternative, especially for deep-water offshore siting due to their low center of gravity, ease of access to drivetrain components, and overall simplicity. Due to the absence of a pitch mechanism in large-scale Darrieus VAWTs, stall control has often been used to manage power and loads. Introducing a pitching mechanism in H-type VAWTs has been studied, but this diminishes the mechanical simplicity advantage, and the use of a pitching mechanism in a large-scale Darrieus-type VAWT is not practical. This work examines an innovative, alternative method to control the rotor dynamics of a large-scale 5 MW VAWT to maximize power while constraining loads without introducing any new or complex mechanical elements. This control strategy is termed intracycle revolution per minute (RPM) control, where the rotational speed of the turbine is allowed to vary in an optimal fashion with the azimuthal location of blades as opposed to typical constant RPM operation. An optimization framework is formulated for an open-loop optimal control problem and solved to maximize power subject to constraints on aerodynamic design loads. Results are presented to demonstrate the benefits and the performance limits of intracycle RPM control for large-scale 5 MW Darrieus VAWTs, namely, (1) power production (quantified in terms of AEP) that can be increased subject to baseline load limits and (2) opportunities to significantly increase AEP or decrease loads via intracycle RPM control that are examined for both two-bladed and three-bladed VAWTs.     

Thioethers and sulphones of 7H-benzimidazo(2,1-a)benz-(d,e)isoquinolin-7-one: Dyes for synthetic-polymer fibres

A series of 4-alkylthio and 4-arylthio-1, 8-naphthalic anhydrides was obtained either by reaction of 4-chloro-1,8-naphthalic anhydride with thiols or of 4-mercapto-1,8-naphthalic anhydride with halides; oxidation of these afforded the corresponding sulphones. Reaction of the thioethers and sulphones with o-phenylenediamines gave bright orange-yellow and greenish-yellow dyes respectively; these compounds have excellent colouration and fastness properties on synthetic-polymer fibres. The dyes were also obtained by condensation of 3- and 4-halogeno-7H-benzimidazo(2,1-a)benz(d,e)isoquinolin-7-ones with the appropriate thiol. The colour of the dyes is discussed in relation to structural changes in the thioether and sulphone substituents and the influence of substitution in each of the phenyl rings of the naphthyl residue is compared from an unambiguous synthesis of selected 3- and 4-thioethers and sulphones of 7H-benzimidazo(2,1-a)benz(d,e)isoquinolin-7-one.     

Automated robotic grinding by low-powered manipulator

A new robotic grinding process has been developed for a low-powered robot system using a spring balancer as a suspension system. To manipulate a robot-arm in the vertical plane, a large actuator torque is required due to the tool weight and enormous gravity effect. But the actuators of the robot system always exhibit a limited torque capacity. This paper presents a cheap and available system for precise grinding tasks by a low-powered robot system using a suspension system. For grinding operations, to achieve position and force-tracking simultaneously, this paper presents an algorithm of the hybrid position/force-tracking scheme with respect to the dynamic behavior of a spring balancer. Material Removal Rate (MRR) is developed for materials SS400 and SUS304. Simulations and experiments have been carried out to demonstrate the feasibility of the proposed system.     

Maximum density effects on natural convection in a porous cavity under thermal non-equilibrium conditions

Summary The problem of natural convection flow in a cavity filled with a water near its maximum density saturated porous medium and subjected to thermal non-equilibrium condition is investigated numerically in the present article. The natural convection flow in the horizontally heated rectangular cavity is assumed to be two-dimensional. A parabolic relationship of the density-temperature is used in Darcy's model. The dimensionless governing equations were solved using the finite volume method, and the results are presented to show the effect of the governing parameters. The numerical results are presented in the form of variations of the average Nusselt number with the Rayleigh number with different values of the heat transfer coefficient parameter H, and the thermal conductivity parameter K _r . It is found that by increasing H and K _r the shape of the isotherms of the solid phase appear to be similar to those of the water due to the enhancement of the thermal communications between the two phases. The results for the average Nusselt number of the thermal equilibrium model, which is the maximum possible value, can be achieved for high values of H×K _r . The numerical results reveal the dependence of the total (solid + fluid) average Nusselt number on the aspect ratio, and the maximum values of the average Nusselt number are found for the cavities of aspect ratio A≈0.5.     

Reliability Forecasting of a Load‐Haul‐Dump Machine: A Comparative Study of ARIMA and Neural Networks

Both the autoregressive integrated moving average (ARIMA or the Box–Jenkins technique) and artificial neural networks (ANNs) are viable alternatives to the traditional reliability analysis methods (e.g., Weibull analysis, Poisson processes, non‐homogeneous Poisson processes, and Markov methods). Time series analysis of the times between failures (TBFs) via ARIMA or ANNs does not have the limitations of the traditional methods such as requirements/assumptions of a priori postulation and/or statistically independent and identically distributed observations for TBFs. The reliability of an LHD unit was investigated by analysis of TBFs. Seasonal autoregressive integrated moving average (SARIMA) was employed for both modeling and forecasting the failures. The results were compared with a genetic algorithm‐based (ANNs) model. An optimal ARIMA model, after a Box–Cox transformation of the cumulative TBFs, outperformed ANNs in forecasting the LHD's TBFs. Copyright © 2015 John Wiley & Sons, Ltd.