Prospect of Enhanced Geothermal system in baseload power generation

Given the strength of commodity prices in recent years, concerns over energy security and widening adoption of carbon emission pricing, renewables are well positioned to play growing role in global energy mix. Geothermal energy is on the face of it. By harnessing the heat of the earth, geothermal power plants tap into a virtually inexhaustible and continuous source of energy, using a small footprint facility to provide baseload electricity that is virtually CO2 and waste free. Geothermal projects today center on the exploitation of hydrothermal resources- reservoirs of naturally occurring water. This could change with Enhanced Geothermal System (EGS), a new form of geothermal exploitation being tested in areas that are not hydrothermal. This paper discusses the prospect of Enhanced (or Engineered) Geothermal System as a means to the baseload power generation. It also focuses on the technology behind creating engineered reservoirs, drilling costs and also the economics involved. It also reviews the environmental impacts as well as the areas for possible developments

Feature extraction of human sleep EEG signals using Wavelet Transform and Fourier Transform

Electroencephalogram (EEG) is a complex signal resulting from postsynaptic potentials of cortical pyramidal cells and an important brain state indicator with specific state dependent features. Modern brain research is intimately linked to the feasibility to record the EEG and to its quantitative analysis. EEG spectral analysis is an important method to investigate the hidden properties and hence the brain activities. Spectral analysis of sleep EEG signal provides acute insight into the features of different stages of sleep which can be utilized to differentiate between normal and pathological conditions. This paper describes the process of extracting features of human sleep EEG signals through the use of multi resolution Discrete Wavelet Transform and Fast Fourier Transform. Discrete Wavelet Transform offers representations of the signals in the time-frequency plane giving information regarding the time localization of the spectral components at different stages of sleep in human beings and Fast Fourier Transform provides the spectral information. This paper also discusses the clinical correlation associated with sleep EEG signals in brief

Study of antioxidant activity and free radical scavenging power of Rheum Ribes flower extract

In recent years, the use of synthetic antioxidants and the degradation products derived from them is limited, because they are toxic and carcinogenic. So, studying on the use of natural antioxidants to replace the synthetic antioxidants is very important. Natural antioxidants are healthier and have more benefits and fewer harmful side effects. In this study, first, the Rheum Ribes of flower was extracted by maceration method with methanol. The extract’s phenolic compounds and inhibitory activity of free radicals were evaluated in different concentrations (100, 150, 200, 250 and 300 ppm) by Folin-Ciocalteu method and DPPH test, respectively and then, compared with the synthetic antioxidant of BHT at the constant concentration of 200 ppm. The results showed that the highest antioxidant properties of the extract was related to the concentration of 300 ppm and also the concentration of 250 ppm of the extract of Rheum Ribes of flower was equivalent to a concentration of 200 ppm of BHT in terms of free radical scavenging properties.Keywords: Rheum Ribes flower, Free radical scavenging power, Natural antioxidants, Phenolic compound

Comparison of transthoracic echocardiography and right heart catheterization for assessing pulmonary arterial pressure in patients with congenital or valvular heart defects

Background- Although right heart catheterization (RHC) has acceptable accuracy for the measurement of pulmonary arterial pressure (PAP), significant risks and cost issues are worrisome. Thus, a non-invasive technique such as echocardiography for assessing PAP would clearly be of great clinical value. We aimed to compare estimated systolic PAP (SPAP) by echocardiogram with the actual RHC measurements in the two groups of congenital and valvular heart diseases (CHD and VHD, respectively), in whom pulmonary hypertension (PHT) was clinically suspected. Methods- A total of 103 consecutive patients with confirmed CHD or VHD referred to our center between January and December 2009 were studied. Participants underwent transthoracic echocardiography and RHC within 4 hours of each other. Results- The mean SPAP in the CHD group was no different measured by RHC or echo (46.49 ± 29.04 vs. 46.45 ± 23 mmHg, p = 0.541). The mean SPAP in the VHD group measured by RHC was significantly higher than that measured by echo (48.70 ± 14.50 vs. 44.90 ± 11.0 mmHg, p = 0.041). Fifty-one (49.5) patients were found to have PHT at RHC. Echocardiography correctly identified 48 of these patients (sensitivity= 94.1). Nineteen of the 52 patients without PHT on RHC were correctly identified by echocardiography (specificity= 36.5). The positive and negative predictive values for echocardiography in assessing the presence or absence of PHT were 59.3 and 86.4, respectively. Conclusion- Integration of hemodynamic data with the echo examination can appropriately provide comprehensive assessment of PHT with high sensitivity in individual patients with congenital or valvular heart defects

Influence of Annealing Temperature on the Properties of ZnO Thin Films Grown by Sputtering

AbstractZinc oxide (ZnO) thin films were deposited by RF magnetron sputtering onto ITO coated soda-lime glass substrates. The effects of annealing in temperature range of 250 to 450°C on the structural and optical properties of the ZnO films have been studied. The crystalline structure, surface topology, morphology, optical properties of the films were determined using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and UV–Visible Spectrometry, respectively. X-ray diffraction measurement showed that the annealed ZnO films were polycrystalline in nature with (002), (101) and (001) oriented crystallites of hexagonal wurtzite structure. Crystalline property and grain size of the films were found to increase after annealing. The optical band gap of ZnO films initially blue shifted (3.1–3.23eV) when annealed at 400°C and further red shifted in the range of 3.23 to 3.1eV being annealed at 250 to 450°C range. From the UV spectroscopy, the films showed transmittance over 85% in the optical bandgap spectrum. All these results indicate that post deposition annealing improves the film quality with reduced roughness and better crystalline properties that can be utilised as buffer layer in the CIGS or CdTe thin film solar cells

Group profile creation in ubiquitous healthcare environment applying the analytic hierarchy process

Nowadays, the personalization in ubiquitous healthcare is of utmost importance for enabling the provision of services tailored to the patient’s needs and interests. The personalization of the ubiquitous healthcare services is based on the profiles of the entities participating in these services. Such an application is the dynamic creation of the group of the entities that is formed to deliver the healthcare service to the patient. In this paper, we propose an approach for achieving creation of group profiles in a ubiquitous healthcare environment applying the Analytic Hierarchy Process

Investigation Study of Three-Level Cascaded H-bridge Multilevel Inverter

This paper analyzed three-level Cascaded H-bridge Multilevel Inverter (CHMLI) utilizing two modulation techniques namely Sinusoidal Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM). The performance and the output of CHMLI in terms of Total Harmonic Distotion (THD) % and circuits complexity were compared. The simulations models were constructed using MATLAB/SIMULINK. The results showed the CHMLI produced the lowest THD contents and utilized fewer components. Moreover, the SVPWM produced less THD than SPWM