SOUTHERN JOURNAL OF SCIENCES

Background: Antioxidant compounds are widely used in medicine to protect the organism from the impact of various stresses and strengthen the immune system. The primary source of natural antioxidants is considered plant-based products. That is precisely why scientists are interested in extracting active compounds out of plant materials and use them. However, diverse resources of medicinal plants of Georgia is poorly studied and used as a source of antioxidants. Aim: The research aimed to study the antioxidant composition and total antioxidant activity of some dried medicinal plants sold in the pharmacy network in Tbilisi, Georgia. Methods: Several types of medicinal plants (3 berry plants and 3 herbaceous plants) sold in the pharmacy chain were chosen as the research object. These are Crataegus sp., Sorbus sp., Viburnum sp., Helichrysum sp., Leonurus quinquelobatus Gilib, Origanum vulgare L. Results: As a result, it has been found that the content of ascorbic acid and carotene in the studied plants is not so high to fill the daily intake of a man with an infusion prepared from one tablespoon. As for proline and the number of total antioxidants, all the plants we have chosen are high in content, considerably increasing their medicinal value. Discussion: The low amount of ascorbic acid and carotine found in studied plant, this increases their medicinal value, and in combination with other antioxidants/plants, the healing effect of the raw materials has been used. Conclusions: The studied plants are characterized by high levels of proline and antioxidant activity, so their infusions can be safely used as a source of antioxidants both in folk medicine and for the preparation of biologically active preparations.

Background: A client requested that the study group help determine locations that would be suitable for a drilling regime at his lot, located at an upslope rocky knoll of Lawu Estate, Minna, Nigeria. Aim: The aim of this study is to carry out a purpose-specific survey to pinpoint the best locations in a built-up property at the upmarket Lawu Estate that would be suitable for a drilling regime targeted for household consumption. Methods: The study area was reconnoitered by the survey crew in order to georeference the locations that would be occupied for the vertical electrical sounding survey in the 30 m x 20 m lot. Owing to the extensive build-up at this lot, only a four-point traverse along the 30-metric dimension traverse of the frontage of the building was demarcated in the northeasterly direction, thereby limiting the desire of the survey crew to define an appropriate survey grid. The data-acquisition pattern at the 4 x 1 survey stations of the frontage-traverse of the lot followed the “traditional” sequence of Schlumberger array layout measurements, whence the survey crew progressed with current-electrode spacing either end of a survey point located at this frontage-traverse targeting a maximum survey depth of 100 m. Result: The acquired vertical electrical-sounding data set for this study was recorded on purpose-specific data sheets. Discussion: Based on empirical rules-of-thumb procedures for interpreting vertical electrical sounding data at the Nigerian Basement Complex geological province, “assured” groundwater location and “strongly aquiferous” location, deductive inferences were drawn with regards to only vertical electrical sounding Station 4. Conclusion: Thus, it is recommended that VES Station 4 be exploited in the planned drilling program of the client, especially since this survey point checks off 100 percent of the constraints imposed by the rules-of-thumb interpretation procedures.

Background: MQ-series gas sensors belong to the metal oxide semiconductor (MOS) family of sensors that can sense the presence of many gases. These sensors find their application in gas alarm systems as key components. While necessary sensor circuit output voltage value for alarm point in a stand-alone gas alarm system is desirable, but what exact combination of the sensor circuit parameters is required? Hitherto, the determination of these circuit parameters has not been given much attention in the research community. Aim: the purpose of this work is to explore a structured graphical approach of determination of MQ series gas sensor circuit parameters for a stand-alone gas alarm system that yields desired sensor circuit output voltage value for the alarm point; the main objective of the study was to develop mathematical model equations that relate the: (i) sensor resistance (RS) with the gas concentration (x) and the sensor resistance at standard calibration concentration of the sensor base gas in the clean air (Ro) and (ii) sensor circuit output voltage (VRL), load resistance (RL) and sensor resistance (RS). It is expected from the model equations developed that graphical correlations of the sensor circuits parameters will be generated. Using these graphs for a particular case of an MQ-4 gas sensor under the influence of LPG, the parameters that yield desired sensor circuit output voltage of 2V for 1000 ppm of LPG alarm point will be determined. Methods: Model equations were developed for the sensor dynamics, and based on these model equations, graphs for the determination of required sensor parameters were plotted for a case of MQ-4 gas sensor response to LPG. Results and Discussion: The results yielded optimal values for R_O,R_S and R_L of 20 kΩ, 30 kΩ and 20 kΩ respectively, for alarm settings of 1000 ppm and a desired sensor circuit output voltage of 2 V. Based on determined parameters, the calibration equation for determination of best concentration value for a given value of emulated LPG concentration was developed. Using the method proposed in this study makes the process of determining the MQ-series gas sensor circuit parameters less cumbersome as their value can easily be obtained from the resulting graphs. Conclusions: a structured graphical approach for determination of MQ-series gas sensor circuit parameters for alarm points in a stand-alone gas alarm system showed that using MQ-4 gas sensor and LPG as the target gas, and for a sensor circuit output voltage of 2 V for alarm point at 1000 ppm of LPG, the corresponding value of R_O, R_S and R_L obtained were 20 kΩ, 30 kΩ, and 20 kΩ respectively. Hence, a structured graphical approach is suitable for determining MQ series gas sensor circuit parameters for a stand-alone gas alarm system under the influence of its associated gases.