The Effect of Static Magnetic Field on E. coli, S. aureus and B. subtilis Viability

This study investigated the effects of low static magnetic field on the growth of three bacterial strains (Escherichia coli, Staphylococcus aureus and Bacillus subtilis) that plays a versatile role in infecting wounded tissues. The viability of these bacteria was measured with and without different magnetic fields (30, 50, and 80) mT after 24 hours. Results illustrate that magnetic field decreased the growth rate of Escherichia coli and Staphylococcus aureus bacteria, while increased the growth rate of Bacillus subtilis after 24 hours of exposure. Keywords: Magnetic field, Bacillus subtilis, Escherichia coli, Staphylococcus aureus

Antibacterial And Antifungal Effect Of Some Natural Extracts And Their Potential Use As Photosensitizers

One of the threats on the health sector is the appearance of multi antibiotic resistant microorganisms. Thus, this occurs because of using natural and synthetic antimicrobial agents in excessive doses. Now, many scientists all around the world are performing research on natural extracts that have antimicrobial activity using photodynamic therapy (PDT) which involves light activation. The aim of this study, however, is to evaluate the effect of photodynamic antimicrobial chemotherapy using extracts from Pomegranate (Punica granatum), Cinnamon (Cinnamomum verum), Roselle (Hibiscus sabdariffa), Carob (Ceratonia siliqua), and Nigella or black cumin oil (Nigella sativa) against two gram-positive and two gram-negative bacteria (Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) respectively; and three different fungi (Aspergillus niger, Mucor sp., and Rhizopus sp.), using agar well diffusion method. The prepared methanolic extracts presented absorption between 300 and –900 nm wavelengths. The maximum activity of Roselle (Hibiscus sabdariffa) was against Staphylococcus aureus in total darkness with 52.5 ± 2.5 mm inhibition zone diameter. Also, the most sensitive fungi was Mucor sp. Cinnamon (Cinnamomum verum) extract was with 31.0 ± 1.0 mm inhibition zone diameters. The results showed that there was an inhibitory effect of Cinnamon (Cinnamomum verum) and Roselle (Hibiscus sabdariffa) extracts against most of the tested species

Antimicrobial Activity of Varthemia iphinoides and Majorana syriaca Essential Oils from Jordan and Their Potential Use as Natural Food Preservatives

The aim of this study was to evaluate the efficiency of Varthemia iphinoides and Majorana syriaca essential oils as natural food preservative in four different food model media (cheese, meat, milk, and tomato) against two gram-positive and two gram-negative bacteria (Bacillus cereus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) and three different food spoilage fungi using agar well diffusion method. The results showed that the maximum activity of V. iphinoides essential oil was against S.aureus in tomato media with relative inhibition zone diameter (RIZD) 186 ± 9 %, the most sensitive food spoilage fungi was penicillium sp. in tomato media with RIZD 149 ± 10 %. The results showed that there was inhibitory effect of M. syriaca and V. iphinoides essential oils. against most of the tested species in different food model media which will lead to control food pathogen organisms by using essential oils as food preservative and flavoring agents. Key words: Varthemia iphinoides , Majorana syriaca, Essential oils, Antimicrobial, Food preservative

Towards green energy for smart cities: particle swarm optimization based MPPT approach

This paper proposes an improved one-power-point (OPP) maximum power point tracking (MPPT) algorithm for wind energy conversion system (WECS) to overcome the problems of the conventional OPP MPPT algorithm, namely, the difficulty in getting a precise value of the optimum coefficient, requiring pre-knowledge of system parameters, and non-uniqueness of the optimum curve. The solution is based on combining the particle swarm optimization (PSO) and optimum-relation-based (ORB) MPPT algorithms. The PSO MPPT algorithm is used to search for the optimum coefficient. Once the optimum coefficient is obtained, the proposed algorithm switches to the ORB MPPT mode of operation. The proposed algorithm neither requires knowledge of system parameters nor mechanical sensors. In addition, it improves the efficiency of the WECS. The proposed algorithm is studied for two different wind speed profiles, and its tracking performance is compared with conventional optimum torque control (OTC) and conventional ORB MPPT algorithms under identical conditions. The improved performance of the algorithm in terms of tracking efficiency is validated through simulation using MATLAB/Simulink. The simulation results confirm that the proposed algorithm has a better performance in terms of tracking efficiency and energy extracted. The tracking efficiency of the PSO-ORB MPPT algorithm could reach up to 99.4% with 1.9% more harvested electrical energy than the conventional OTC and ORB MPPT algorithms. Experiments have been carried out to demonstrate the validity of the proposed MPPT algorithm. The experimental results compare well with system simulation results, and the proposed algorithm performs well, as expected

A Cost-Effective Method for Power Factor ‎Metering Systems ‎

The power factor (PF) is an important measurement in an AC electrical system that indicates how much power ‎is utilized to accomplish productive work by a load and how much power is consumed. As a result, it\u27s one of ‎the primary causes of excessive energy costs and power outages. This paper aims to present a simple, cost-‎effective, and accurate PF metering and monitoring system implemented using an Arduino microcontroller with ‎a novel methodology different from other papers. The proposed method is to design the software code instead ‎of using external components of Zero-Crossing Detectors (Z-CDs) for both voltage (V) and current (I) signals, and ‎instead of using Exclusive-OR (X-OR) gates also. Determining the phase-angle and PF in an efficient manner ‎can be useful in many approaches to electrical systems: 1-for synchronization of parallel connections of ‎alternators; 2-for directional protection systems; 3-for PF correction and load management; and 4-for designing ‎watt/energy meters. Using the Proteus 8 Professional (ISIS program), the proposed designed circuit was ‎simulated for more verification. The simulation and experimental findings are presented to validate the ‎proposed metering system\u27s effectiveness.

Multi-state analysis of process status using multilevel flow modelling and Bayesian network

Multilevel Flow Modeling (MFM) model maps functionality of components in a system through logical interconnections and is effective in predicting success rates of tasks undertaken. However, the output of this model is binary, which is taken at its extrema, i.e., success and failure, while in reality, the operational status of plant components often spans between these end. In this paper, a multi-state model is proposed by adding probabilistic information to the modelling framework. Using a heat exchanger pilot plant as a case study, the MFM model is transformed into its fault tree [1] equivalent to incorporate failure probability information. To facilitate computations, the FT model is transformed into Bayesian Network model, and applied for fault detection and diagnosis problems. The results obtained illustrate the effectiveness and feasibility of the proposed method

Signal distortion due to stimulated Raman scattering in optical CDMA transmission systems

In this paper, the signal distortion due to stimulated Raman scattering (SRS) in incoherent optical code-division multiple-access (OCDMA) transmission systems is evaluated at different transmission distances. A number of computer simulations have been conducted for this purpose. It is shown that as the total transmit power exceeds Raman threshold level, the SRS will cause severe signal deterioration over long distances even in the absence of the other signal impairment factors

Optical power limitations in spectral-amplitude- coding optical code-division multiple-access systems due to stimulated Raman scattering

In is paper, the maximum power per chip to keep the Stimulated Raman Scattering (SRS)- induced tilt below a specific level in Spectral-Amplitude-Coding Optical Code-Division Multiple-Access (SAC-OCDMA) is evaluated for different number of users. A number of computer simulations have been conducted for this purpose. It is shown that as number of users grows, the power per chip must be decreased to control the SRS-induced tilt and to keep it below acceptable levels. It is also shown that SRS-induced tilt can significantly limit the power per chip levels when the number of users is large. This is the first time such a study is reported for OCDMA systems

The optimum condition for the synthesis of carbon nanofibers on activated carbon to remove lead from aqueous solution

Optimum process condition for the production of Carbon Nanofibers (CNFs) to remove lead ion (Pb) from aqueous solution is reported here. The CNFs were produced on the catalyst (Ni2+) impregnated palm oil-based cheap Powder Activated Carbon (PAC). Locally fabricated Chemical Vapour Deposition (CVD) system was used while acetylene (C2H2) was the carbon source. The porous nano-composite product is named “PAC-CNFs”, which was synthesized through a process using impregnated oil palm shell based PAC as a solid substrate. Design Expert 6.0.8 software was used to design the experimental plan and to determine the optimized process parameters for the growth of CNFs by using sorption capacity for Pb2+ by the PAC-CNFs adsorbent, as a response. The effect of different factors on the growth of CNFs including the temperature of CNFs growth (550 to 750 °C), time of growth (30 to 60 min), and the ratio of input C2H2/H2 gases (0.25 to 1.0) was evaluated. The predicted values for the sorption capacity of Pb2+ by the PAC-CNFs were in close agreement with the experimental data (R2 = 0.99). The optimal process condition: temperature for the growth of CNFs, time, and C2H2/H2 ratio was determined as 637 °C, 30 min, and 1.0, respectively. The CNFs grown under the optimized condition exhibited sorption capacity of 77 mg/g in removing Pb2+ from synthetic wastewater containing lead (Pb2+) ion