EFFECT OF DIFFERENT PERIODS OF IRRIGATION AND ASCORBIC ACID ON GROWTH, YIELD AND QUALITY OF ESSENTIAL OIL OF MENTHA PIPERITA L. PLANTS

The present study was carried out during two growing seasons (2019 and 2020) at the Nursery of Department of Floriculture, Ornamental Horticulture, Faculty of Agriculture, Alexandria University, Egypt to study the effect of irrigation intervals (4 days as control stress, 8 days as moderate stress and 12 days as severe stress) and ascorbic acid (AsA) at 0, 100, 150, 200, 250 mg l-1 on the growth, quantity and quality of the essential oil of Mentha piperita L. plants. The main results of this study indicated that most of the vegetative growth characteristics were increased when AsA was applied at 150 or 200 mg l-1 to the plants grown under control stress (irrigation interval at 4 days). AsA at 200 mg l-1 was more effective on leaves fresh weight than 150 mg l-1 which affects mostly the number of branches of the plants grown under moderate stress (irrigation interval at 8 days). Increasing irrigation interval to 12 days (severe stress) in addition to AsA at 200 mg l-1 decreased the harmful effects in most peppermint plants and leads to obtain high oil percentage and yield. Peppermint oil was analyzed according to GC analysis of fresh leaves grown under water stress and sprayed with ascorbic acid with different concentrations identified 9 components, the major component was menthol with an average of 34.55-52.67% during the three cuts. In general, there was a direct relationship between increasing irrigation intervals and oil components percentage (menthol, menthone and limonene). These results suggest that normal water deficit (4 days irrigation interval) in peppermint will be appropriate to enhance better growth and productivity. In addition, ascorbic acid treatment reduced the damaging action of water stress, especially at concentrations of 150 and 200 mg l-1, so we can conclude that these concentrations are sufficient enough to support peppermint growth, leaves fresh weight and consequently maximum oil yield

An improved optimization technique for estimation of solar photovoltaic parameters

The nonlinear current vs voltage (I-V) characteristics of solar PV make its modelling difficult. Optimization techniques are the best tool for identifying the parameters of nonlinear models. Even though, there are different optimization techniques used for parameter estimation of solar PV, still the best optimized results are not achieved to date. In this paper, Wind Driven Optimization (WDO) technique is proposed as the new method for identifying the parameters of solar PV. The accuracy and convergence time of the proposed method is compared with results of Pattern Search (PS), Genetic Algorithm (GA), and Simulated Annealing (SA) for single diode and double diode models of solar PV. Furthermore, for performance validation, the parameters obtained through WDO are compared with hybrid Bee Pollinator Flower Pollination Algorithm (BPFPA), Flower Pollination Algorithm (FPA), Generalized Oppositional Teaching Learning Based Optimization (GOTLBO), Artificial Bee Swarm Optimization (ABSO), and Harmony Search (HS). The obtained results clearly reveal that WDO algorithm can provide accurate optimized values with less number of iterations at different environmental conditions. Therefore, the WDO can be recommended as the best optimization algorithm for parameter estimation of solar PV

Evaluation of sesamum gum as an excipient in matrix tablets

In developing countries modern medicines are often beyond the affordability of the majority of the population. This is due to the reliance on expensive imported raw materials despite the abundance of natural resources which could provide an equivalent or even an improved function. The aim of this study was to investigate the potential of sesamum gum (SG) extracted from the leaves of Sesamum radiatum (readily cultivated in sub-Saharan Africa) as a matrix former. Directly compressed matrix tablets were prepared from the extract and compared with similar matrices of HPMC (K4M) using theophylline as a model water soluble drug. The compaction, swelling, erosion and drug release from the matrices were studied in deionized water, 0.1 N HCl (pH 1.2) and phosphate buffer (pH 6.8) using USP apparatus II. The data from the swelling, erosion and drug release studies were also fitted into the respective mathematical models. Results showed that the matrices underwent a combination of swelling and erosion, with the swelling action being controlled by the rate of hydration in the medium. SG also controlled the release of theophylline similar to the HPMC and therefore may have use as an alternative excipient in regions where Sesamum radiatum can be easily cultivated