Hibiscus cannabinus L. – Kenaf : A Review Paper

Kenaf (Hibiscus cannabinus L.) is a valuable fiber and medicinal plant from the Malvaceae family. It is an alternative crop that may be a feasible source of cellulose which is economically viable and ecologically friendly. This plant is cultivated for its fiber although its leaves and seeds have also been used in traditional medicine in India and Africa for the treatment of various disease conditions. Kenaf fibers are commonly used for paper pulp and cordage, but it is also a promising lignocellulosic feedstock for bioenergy production. The kenaf seed oil can be used for cooking and in different industrial applications. The present paper is an overview on its ethnobotanical and phytochemical properties reported in the literature that we have investigated and its great potential as a valuable multipurpose crop due to numerous uses.     

Coupling of local visualization and numerical approach for particle microfiltration optimization

The performance of the microfiltration process is controlled by the filter fouling due to the accumulation of solid matter forming a cake layer on the membrane surface. The objective of this work is to study the cake build up and growth at the particle level and to establish correlations with microfiltration performance measured at the process scale. A theoretical model coupling Navier–Stokes equation, convective/diffusion particle transport and deposit formation is developed to simulate a sequence of microfiltration in a confined geometry (Comsol Multyphysics^®). This model is used to make predictive simulations of cake growth during the filtration of diluted particles in the range of size of microorganism (5 μm). In the same time a specific filtration micro-system including an optical chamber and a microsieve (Aquamarijn^®) filtration membrane is designed in order to perform an experimental approach allowing in situ 3D-visualization of a deposit of model particles (polystyrene fluorescent microspheres) using Confocal laser scanning microscopy (CLSM). Based on image analysis, the cake building and properties (particle arrangement, thickness) are analyzed. These experimental data will be further used to improve the filtration model in order to obtain a predictive tool for process optimization.     

Thermal diffusivities and influence of cooking time on textural,microbiological and sensory characteristics of turkey meat prepared products

Cooking represents an important step in food processing for both sensorial and safety aspects. The aim of this study is to determine (i) the thermal diffusivity and (ii) the impact of cooking time on sensorial and microbiological characteristics of sausages (locally called salami) and ham products prepared from turkey meat. The water immersion method is used for cooking and cooling. Time–temperature profiles and thermal diffusivity values show that heat penetration in ham is slower than heat penetration in salami products. Three cooking times were applied to each material, and cooking time variation had a significant (p < 0.05) effect on the textural parameters of both salami and ham samples. Sensorial tests also showed significant differences (p < 0.05) between products cooked for different times, whereas all three gave acceptable hygienic parameters.     

Characterisation and phenolic profiles of two rare olive oils from southern Tunisia: Dhokar and Gemri‐Dhokar cultivars

BACKGROUND: The aim of this work was to study the chemical characteristics of two Tunisian cultivars, namely Dhokar and Gemri‐Dhokar, to analyse the fatty acids, sterols, triacylglycerols, triterpenic alcohols, and to determine the phenolic composition and oxidative stability. RESULTS: Among the rare varieties, Gemri‐Dhokar olive oil had the highest value of oleic acid (69.39%) whereas Dhokar oil was noteworthy for its lower content of phenolic compounds (94.56 mg kg^?1 gallic acid equivalents of oil) and presented the highest level of palmitic acid (19.37%). The main sterols found in all olive oil samples were β‐sitosterol and Δ5‐avenasterol, whereas cholesterol and 24‐methylenecholesterol were also found in all samples but in lower amounts. Two triterpenic dialcohols (erythrodiol and uvaol) were also detected and their content ranged from 1.45 to 2.30%, in Gemri‐Dhokar and Dhokar olive oil, respectively. Ten phenolic compounds were identified. In all samples, the main phenols found were oleuropein aglycon and pinoresinol. These phenolic compounds showed significant correlations with oxidative stability. CONCLUSION: The analytical parameters of two oils that were determined in this study were greatly influenced by genetic factors (cultivar). © 2012 Society of Chemical Industry     

Deterioration of a Tunisian coastal aquifer due to agricultural activities and possible approaches for better water management

The purpose of this study is to provide a better understanding of the impact of agricultural activities on groundwater quality in a semi‐arid coastal environment (Korba, Tunisia). Impacts have been assessed through groundwater samples that were analysed for a range of chemical and biological parameters. Results indicate that groundwater overexploitation for irrigation and fertiliser use have affected the quality of the groundwater not only by direct contamination but also seawater intrusion. The implementation of appropriate regulatory and economic instruments to foster sustainable practices in the agricultural sector have been analysed within the framework of the EC (European Community) FP6 (funding program 6) INECO (Institutional and Economic Instruments for Sustainable Water Management in the Mediterranean Region) Project. Through stakeholder involvement processes, the project analysed issues relating to the regulation and control of groundwater abstractions, the promotion of wastewater reuse, efficiency improvements in irrigation water use, as well as instruments to strengthen the socioeconomic and institutional environment towards better managing and conserving available groundwater resources.     

Effect of the preparation method on Au/Ce-Ti-O catalysts activity for VOCs oxidation

Studies concerning the preparation of gold phases dispersed on binary Ce-Ti oxide (Ce_0.3Ti_0.7O₂) were performed in order to elaborate catalysts for total oxidation of VOCs. Solids containing gold, cerium and titanium were synthesized by impregnation and deposition precipitation (DP) method using NaOH, Na₂CO₃ or urea as precipitant agent. These catalysts have been characterized by means of total surface area (BET), X-ray diffraction (XRD), diffuse reflectance ultra-violet–visible spectroscopy (DR/UV–vis) and temperature programmed reduction (TPR) and their reactivity towards the oxidation of propene was studied. Thus, it was revealed that the gold-based material prepared by DP method using urea as precipitant agent was the most efficient catalyst towards the total oxidation of propene. Based on the characterisation data, it has been shown that the preparation method has an effect on the catalytic activity.     

Self-Calibration of Output Match and Reverse Isolation in LNAs Based Switchable Resistor

With recent advances in CMOS process technology, the concept of system-on-a-chip (SoC) has been realized by integrating more and more digital and analog building blocks in a single chip [2, 9]. Additionally, these advances have brought several new types of processes faults (soft fault) and higher process variations to RF circuit resulting performances degradation. In order to compensate the RF circuit performance, a novel efficient self-calibration method for 865?C870?MHz low noise amplifiers (LNAs), which constitute a RF mixed-signal circuit, is developed. This technique detects any deviation from the output match and from reverse isolation using built-in self test (BIST) methods, and then provides a corrective measure to recalibrate these LNA performances to the possible optimal value. This proposed self-calibration technique uses a switchable resistor which has been designed to investigate its ability to compensate for output match S22 and reverse isolation S12 without affecting other LNA performances. The use of this method saves space on chip and prevents adding switch resistor noise. In addition, the new calibration design shows the ability to calibrate S22 and S12 due to the catastrophic fault.     

Synchronous optical detection unmasked

In this article we presented a new silicon optoelectronic receiver in standard CMOS for synchronous detection of light. Two versions were implemented in a 0.7-μm N-well CMOS technology and tested. In the better version, the light-sensitive junctions were the drains of NMOSFETs. This version operated at up to 180 MHz with external 830-nm light pulses of 176 fJ. Our new receiver shows an excellent trade-off between small size, high speed, and good sensitivity, and is therefore an interesting candidate for applications such as digital optical information transfer between VLSI circuits