145 research outputs found

    Applications of frames of subspaces in Richardson and Chebyshev methods for solving operator equations

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    This paper is concerned with the construction of two iterative methods by frames of subspaces for solving an operator equation on Hilbert spaces. We present two algorithms based on Richardson and Chebyshev methods, and investigate their convergence and optimality

    Adaptive methods for solving operator equations by using frames of subspaces

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    In this paper, using a frame of subspaces we transform an operator equation to an equivalent `2-problem. Then, we propose an adaptive algorithm to solve the problem and investigate the optimality and complexity properties of the algorithm.Publisher's Versio

    Antidiarrheal action of Zataria multiflora hydroalcoholic and hexane extracts in mice

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    Introduction: Zataria multiflora Boiss. is an indigenous herbal plant found in many parts of Iran. This herb is traditionally used as a remedy for treating gastrointestinal disorders including diarrhea. Despite the existence of few pharmacological evidences which support the antispasmodic action of Z. multiflora in vitro, there is no scientific report about therapeutic efficacy of Z. multiflora in animal models. The objective of this research was to investigate the antispasmodic activity of hydroalcoholic and hexane extracts of Z. multiflora on intestinal peristaltic movement as well as assessment of its antidiarrheal action in mice. Methods: Dried leafy branches of Z. multiflora were coarsely powdered and subjected to extraction by ethanol or hexane in a percolator apparatus. Antispasmodic activity of Z. multiflora in vivo was assessed by investigating effect of the extracts on intestinal charcoal meal transit. The antidiarrheal activity of Z. multiflora extracts was evaluated by castor oil and magnesium sulfate-induced diarrhea. The inhibitory effects of the extracts were compared with the standard drug loperamide. Results: The antispasmodic activity of Z. multiflora (20 & 40 mg/kg) hydroalcoholic and hexane extracts was confirmed by a reduction in the distance traveled by charcoal meal alongside the small intestine. Z. multiflora extracts (20 & 40 mg/kg) also significantly attenuated the castor oil and magnesium sulfate-induced diarrhea. Loperamide was more efficacious in reducing number of total stools in both models of diarrhea. Conclusion: The obtained results have established a pharmacological evidence for the folkloric use of the Z. multiflora as an antidiarrhoeal and spasmodic agent

    Determinants of occupational hazards knowledge and safety practices among textile workers in Karachi, Pakistan: A cross sectional study

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    Objective: To determine the factors associated with good knowledge and safe practices regarding occupational hazards among textile workers.Methods: The cross-sectional study was conducted in Karachi from September 2015 to February 2016, and comprised male workers from seven textile mills. A 45-item structured questionnaire was developed and pretested in Urdu, the local language. One part of the questionnaire comprised 31 items related to good knowledge, and the other part comprised 14 items related to safe practices. Data was analysed using SPSS 19.Results: Of the 300 subjects, 123(41%) were aged 18-27 years, 183(63%) were educated, 184(61.3%) worked more than eight hours daily, 170(57%) were employed in the weaving section and 164(55%) as machine operators. Besides, 231(77%) had good knowledge, and 62(21%) reported safe practices. Educated workers were more likely (p\u3c0.05), and machine operators were less likely (p\u3c0.05) to have good knowledge, while educated workers, those in the spinning section and those working less than 8-hours daily (p\u3c0.05) were more likely to report safe practices.Conclusions: There was a high knowledge level, but a wide gap in adopting safety practices, which indicates need for focused interventions targeting high-risk workers and regulation of working hours

    Intensification of toxic chlorophenolic compounds degradation over efficient microwave-dried silica-doped tetragonal zirconia nanocatalysts

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    The work aims to evaluate the efficient microwave (MW) drying method of silica-doped tetragonal zirconia nanocatalysts (SZN-M) for intensification of the degradation of toxic chlorophenolic compounds. The catalyst dried under a conventional oven (SZN-O) was also conducted for comparison. The MW drying time was reduced six times and three times less energy was used than the conventional oven drying. The catalysts were characterized by Fourier-transform infrared, X-ray diffraction, electron spin resonance, nitrogen adsorption-desorption analyses, zeta potential, ultraviolet–visible diffuse reflectance spectroscopy and photoluminescence analyses. Compared with SZN-O, the SZN-M possessed a higher number of Si-O-Zr bonds that led to a greater amount of oxygen vacancies, metal defect sites, larger pore size as well as surface area, and hence displayed excellent performance toward the degradation of toxic 2-chlorophenol, 2-CP (92%), while only 67% for the former. The SZN-M achieved to reduce the total organic carbon and biological oxygen demand up to 88% and 89%, respectively, while for SZN-O, the reduction was up to 82% and 84%. The catalysts still remained active after five cycles and are highly capable of degrading various chlorophenolic compounds that could be very beneficial for the wastewater treatment

    Residual refractive errors in pseudophakic eyes and related factors: a population-based study

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    AIM: To determine residual refractive error after cataract surgery in pseudophakic eyes and its relationship with age, sex, and axial length (AL). METHODS: In this population-based cross-sectional study, the sampling was performed on individuals aged 60y and above in Tehran, Iran using a multi-stage stratified random cluster sampling method. Pseudophakic eyes with a best-corrected visual acuity of 20/32 or better were analyzed and their refractive results were reported. RESULTS: The mean spherical equivalent (SE) refraction was -0.34±0.97 diopters (D) and the mean absolute SE was 0.72±0.74 D with a median of 0.5 D. Moreover, 32.68% (n=546, 95%CI: 30.27%-35.08%), 53.67% (n=900, 95%CI: 51.23%-56.1%), 68.99% (n=1157, 95%CI: 66.96%-71.02%), and 79.73% (n=1337, 95%CI: 77.69%-81.76%) of the eyes had a residual SE within ±0.25, ±0.50, ±0.75, and ±1.00 D of emmetropia, respectively. According to the multiple logistic regression model, increasing age was associated with a statistically significant decrease in predictability for all cut points. Moreover, the predictability based on all cut points was significantly lower in individuals with an AL longer than 24.5 mm than in those with an AL between 22 to 24.5 mm. CONCLUSION: Based on the results, the accuracy of intraocular lens (IOL) power calculation is lower for those who underwent cataract surgery during the last 5y in Tehran, Iran. Among the most important influential factors, the choice of IOL or it's power disproportionate to eye conditions and age can be mentioned

    Implementation of Evolutionary Algorithms to Parametric Identification of Gradient Flexible Plate Structure

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    This paper focused on modelling of a gradient flexible plate system utilizing an evolutionary algorithm, namely particle swarm optimization (PSO) and cuckoo search (CS) algorithm. A square aluminium plate experimental rig with a gradient of 30° and all edges clamped were designed and fabricated to acquire input-output vibration data experimentally. This input-output data was then applied in a system identification method, which used an evolutionary algorithm with a linear autoregressive with exogenous (ARX) model structure to generate a dynamic model of the system. The obtained results were then compared with the conventional method that is recursive least square (RLS). The developed models were evaluated based on the lowest mean square error (MSE), within the 95% confidence level of both auto and cross-correlation tests as well as high stability in the pole-zero diagram. Investigation of results indicates that both evolutionary algorithms provide lower MSE than RLS. It is demonstrated that intelligence algorithms, PSO and CS outperformed the conventional algorithm by 85% and 89%, respectively. However, in terms of the overall assessment, model order 4 by the CS algorithm was selected to be the ideal model in representing the dynamic modelling of the system since it had the lowest MSE value, which fell inside the 95% confidence threshold, indicating unbiasedness and stabilit

    Decentralized Intelligent PID based controller tuned by Evolutionary Algorithm for Double Link Flexible Robotic Manipulator with Experimental Validation

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    In this paper, a development of decentralized intelligent proportional–integral–derivative (PID) controller for multi input multi output (MIMO) controller of double link flexible robotics manipulator is presented. Simultaneous optimization method is implemented in optimizing the parameters. The controllers are incorporated with optimization algorithm that is PSO to find out the parameters of the PID controllers. Numerical simulation was carried out in MATLAB/Simulink to evaluate the system in term of tracking capability and vibration suppression for both links. The optimal values of PID controller parameters that were achieved via off-line tuning using PSO were tested experimentally on the DLFRM experimental test rig. Experimental results show that the proposed control algorithm managed to control the system to reach desired angle for both hub at lower overshoot. Meanwhile, the vibration reduction shows improvement for both link 1 and 2. This signifies that, the PSO algorithm is very effective in optimizing the PID parameters for double link flexible robotics manipulator

    Exploration of Shallow Geothermal Energy Aquifers by Using Electrical Resistivity Survey in Laki Range Jamshoro district Sindh, Pakistan

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    Geothermal water is increasingly used around the world for its exploitation. Bulk electrical resistivity differences can bring significant information on variation of subsurface geothermal aquifer characteristics. The electrical resistivity survey was carried out in Laki range in lower Indus basin in the study area to explore the subsurface geothermal aquifers. The Schlumberger electrode configuration with range from 2 m to 220 m depth was applied. Three prominent locations of hot springs were selected including Laki Shah Saddar, Lalbagh and Kai hot spring near Sehwan city. After processing resistivity image data, two hot water geothermal aquifers were delineated at Laki Shah Sadder hot springs. The depth of first aquifer was 56 m and its thickness 38 m in the limestones. The depth of second aquifer of 190 m and with thickness of 96 m hosted in limestone. In Lalbagh hot springs two geothermal aquifers were delineated on the basis of apparent resistivity contrast, the depth of first aquifer zone in sandstone was in sandstone 15 m and thickness 12 m, while the depth of second aquifer was 61m and thickness was 35m. In Kai hot springs two hot water geothermal aquifers were delineated. The depth of first geothermal aquifer was 21m and thickness was 18 m and the depth of second aquifer was 105 m and thickness was 61m present in sandstone lithology. Present work demonstrates the capability of electrical resistivity images to study the potential of geothermal energy in shallow aquifers. These outcomes could potentially lead to a number of practical applications, such as the monitoring or the design of shallow geothermal systems

    INVESTIGATION OF GEOTHERMAL ENERGY POTENTIAL USING ELECTRICAL RESISTIVITY SURVEY AND CHEMICAL GEOTHERMOMETERS: A STUDY OF THE MANGHOPIR HOT SPRING KARACHI, SINDH PAKISTAN

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    Electrical resistivity survey and chemical geothermometers methods were used to find the geothermal gradient energy potential of the Manghopir hot spring which is located in Karachi, Sindh. Schlumberger electrode configurations were used to demarcate the two shallow potential subsurface aquifers. At various depths, three lithological units were encountered: alluvium, sandstone, and shale. The first thermal water aquifer lies below at the average depth of 10m and average thickness of 9 m lies in sandstone lithology of Nari Formation of Oligocene age. The second thermal water aquifer encountered at the average depth of 68 m and the average thickness of aquifer was 40.5m in sandstone lithology of Nari Formation. The surface water temperature was calculated with digital thermometer which shows the range in between 48 °C to 50 °C and subsurface temperature was calculated with the help of chemical geothermometers. The Na–K geothermometers indicate the subsurface equilibrium reservoir temperature in the range of 135.52 °C,125.54 °C, 172.964 °C and 184.08°C and the Na-K-Ca chemical geothermometers indicate the subsurface reservoir temperature 148.493°C. The Na-K-Ca geothermometers show a high temperature, but the reservoir temperature appears to be lower due to the mixing of sea water with the chemical composition of hot spring water within the subsurface aquifers
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