Total Power Level Research Articles

Antioxidant status and odour profile in fresh beef from pasture or grain-fed cattle

The main goal of the present work was to determine the overall antioxidant status in fresh meat from animals fed different diets and to differentiate them through their odour profiles. Attributes were evaluated in beef from pasture or grain-fed animals with (PE and GE) or without supplementation (P and G) with vitamin E (500 UI/head/day). Fresh meat produced on pasture (P and PE) had higher total ferric reducing antioxidant power (FRAP) levels than meat from grain fed-animals (G and GE) ( P < 0.05). However, no differences were found on their ability to reduce ABTS + (2,2′-azino-bis-(3-ethylbenz-thiazoline-6-sulfonic acid)), indicating that total antioxidant activity was preferentially due to the reduction potential than to the quenching capacity of tissue homogenates. Two-fold glutathione (GSH and GSSG are the reduced and oxidised forms, respectively) levels were found in the P + PE group respect to G + GE meat ( P < 0.001). In addition, meat from pasture-fed animals presented a higher glutathione redox potential compared to grain-fed animals (−156.1 ± 6.1 and −158.1 ± 6.5 vs. −148.1 ± 13 and −149.8 ± 14.6 for P, PE G and GE, respectively), showing that the antioxidant status in fresh meat was affected by diet. Enzymatic activity of catalase and glutathione peroxidase were equivalent for all dietary groups. Only superoxide dismutase activity was slightly higher ( P < 0.05) in the P + PE group than in G + GE samples. Odour profile analysis was performed in relationship to antioxidant parameters. Significant linear correlation coefficients ( P < 0.05) were found for a set of sensors and the FRAP values. E-nose methodology successfully discriminated the odour characteristics of samples corresponding to pasture- or grain-based diet. Hence, it was possible to describe an analytical relationship between the odour profile and the antioxidant power of fresh meat.

Total power and high frequency components of heart rate variability and risk factors for atherosclerosis

Introduction: Low heart rate variability, HRV, is associated with diabetic neuropathy and with ischemic heart disease, IHD. The time context points to diabetes preceding changes in HRV, while changes in HRV precede the development of atherosclerosis and IHD. The purpose of the study was to analyse the association between the physiological risk factors of IHD and HRV in a prospective design. Methods: In 1998 and 2002, data was gathered in a study concerning the risk factors for atherosclerosis. From among the participants it was possible to include 50 women and 24 men in a sub-study concerning HRV. Heart rate variability was measured partly during a clinical examination with exposure to a simple stress test, and partly during the first 4 h of sleep. The clinical examination, which lasted 45 min, resulted in 9, 5-minute HRV measurements, while the sleep period was divided into 2 periods of 2 h each, for which average HRV measurements were calculated. The associations between HRV and risk factors for IHD were analysed using the GLM, repeated measures method. As the dependent variables in the GLM analyses 11 levels (9 while awake and 2 while sleeping) of total power and high frequency variability, respectively, were used. The included risk factors were; body mass index, waist–hip ratio, systolic blood pressure, fibrinogen, cholesterol, HDL-cholesterol, HbA 1c, testosterone, DHEAs, cortisol and catecholamines. Catecholamines were measured in urine and only in 1998. Cortisol was measured in both urine and saliva in 1998, but only in saliva in 2002. The results were adjusted according to the starting time of the measurements. Results: Among the women, waist–hip ratio and HbA 1c were significantly and negatively associated with both TP and HF. Stress hormones were not associated with HRV. Among the men, waist–hip ratio, HbA 1c, and fibrinogen in 2002, and cortisol and noradrenaline in 1998 were significantly and negatively associated with TP and HF. Conclusion: The study showed gender differences in the observed associations. In both gender, waist ratio and HbA 1c were negatively associated with TP and HF. Furthermore, in the men, but not in the women, stress hormones in 1998, i.e. cortisol and noradrenaline, was negatively associated with TP and HF. The presented data give rise to discussion of the pathophysiology behind heart rate variability and ischemic heart disease, which may be different between women and men.

Progressive video delivery over wideband wireless channels using space-time differentially coded OFDM systems

Progressive video delivery over wireless networks is very challenging due to the time-varying nature of wireless channels and limited power in the mobile devices. This paper proposes an end-to-end architecture for multilayer progressive video delivery over space-time differentially coded orthogonal frequency division multiplexing (STDC-OFDM) systems. An input video sequence is compressed by 3D-ESCOT into a layered bitstream. We input multiple layers of the bitstream in series to a STDC-OFDM channel. Different video source layers are protected by different error protection schemes in order to achieve unequal error protection. In progressive transmission, the reconstruction quality is important not only at the target transmission rate but also at the intermediate rates. So, the error protection strategy needs to optimize the average performance over the set of intermediate rates. We propose to use progressive joint source-channel coding to generate operational transmission distortion-rate (TD-R) functions and operational transmission distortion-power (TD-P) functions for multiple layers before forming the operational transmission distortion-power-rate (TD-PR) surfaces. Lagrange multipliers are then employed on the fly to obtain the optimal power allocation and optimal rate allocation among multiple layers, subject to constraints on the total transmission rate and the total power level. Progressive joint source-channel coding offers the scalability feature to handle bandwidth variations and changes in channel conditions. By extending the rate-distortion function in source coding to the TD-PR surface in joint source-channel coding, our work can use the "equal slope" argument to effectively solve the transmission rate allocation problem as well as the transmission power allocation problem for multilayer video transmission. Experiments show that our scheme achieves significant improvement over a nonoptimal system with the same total power level and total transmission rate.

Effect of antioxidants and antibiotics on levels of seminal oxidative stress in leukocytospermic infertile men.

Defective sperm function is the most common cause of infertility. A prospective study was carried out to correlate the concentration of nitrite (the stable metabolite of nitric oxide) in seminal plasma with leukocytospermia, and sperm membrane integrity. Total Fifty-seven normozoospermic subjects with and without leukocytospermia visiting the Infertility clinic at KH and MRC, Karad, were included in the present study. Semen samples were checked for sperm concentration, total sperm count, sperm motility, seminal leukocyte concentration and sperm membrane integrity as Hypoosmotic Swelling Test. Similarly the concentration of nitrite in seminal plasma was measured by Griess reaction and total antioxidant power measured as ferric reducing ability of plasma. The concentration of nitrite in seminal plasma was found to be raised with significantly increased leukocyte concentration in semen. Also significantly lowered levels of total antioxidant power along with defective sperm function was observed. Our results suggest that supplementary treatment of antioxidants with antibiotic for leukocytospermic infertile male patients may improve the sperm membrane integrity.

Experimental study of the noise emission of personal computer cooling fans

A controlled experimental study of the noise emission of a typical model of computer cooling fan, under different operating conditions, was done. The sound–power levels and directivities of 80-mm-diameter Panaflo computer fans mounted in a test plenum were determined from measurements of sound–pressure level over a hemi-spherical surface above a reflecting plane. The design and testing of the test plenum is discussed. Results of tests performed on one fan unit to gain an understanding of the fan’s noise-radiation characteristics and how they vary with operating conditions are presented. The results show that the noise emission of the Panaflo fan is directly related to the voltage and inversely related to the air-flow rate. It was found that the noise level measured at one particular position corresponds well to the average of those measured at 10 points on the hemisphere. The variability of the noise radiation from these Panaflo fans was determined by testing three other fans; variations of resulting total A-weighted power levels were within 1 dB.

Serum Elevated Levels of Total Antioxidant Power, a biomarker of physiological response to oxidative stress, Correlate with Renal Vascular Damage in Patients with Systemic Sclerosis

Serum Elevated Levels of Total Antioxidant Power, a biomarker of physiological response to oxidative stress, Correlate with Renal Vascular Damage in Patients with Systemic Sclerosis

Investigation of sound radiation by cantilever beam

The research investigates vibration of a cantilever beam loaded with actuators and load. The equation of motion is based on Bernoulli-Euler-Timoshenko theory of beams with corresponding boundary conditions. This equation is solved by the method of Green functions. A feature of this investigation is taking into account the influence of concentrated force parameters, namely the value, location of actuator and phase difference between load and actuator. In the work represented the contribution of actuator parameters on total sound power level as well as on each mode separately.

All-optical wavelength conversion and tuning by the cascaded sum- and difference frequency generation (cSFG/DFG) in a temperature gradient controlled Ti:PPLN channel waveguide

All-optical single and multiple wavelength conversion and tuning by the cascaded sum- and difference frequency generation (cSFG/DFG) have been demonstrated in a temperature gradient controlled periodically poled Ti:LiNbO3 (Ti:PPLN) channel waveguide. Up to 4 channels of wavelength division multiplexed (WDM) signals which have 100 GHz channel spacing were simultaneously wavelength converted at a 16.8 degrees C temperature difference between both end faces in a Ti:PPLN waveguide. The 3 dB signal conversion bandwidth was measured to be as broad as 48 nm at single channel conversion. The maximum wavelength conversion efficiency and optical signal to noise ratio of wavelength converted channel were approximately -16 dB and -20 dB at a total pump power level of 810 mW.

Minimizing gain transient dynamics by optimizing the erbium concentration and cavity length of a gain clamped EDFA

Erbium doped fiber amplifier (EDFA) gain transient dynamics are studied in the context of their application in optically reconfigurable networks. We address the question of how to design the EDFA in order to minimize the gain transients present in the output signals of the EDFA when the system is optically reconfigured such that the total average input power levels and wavelengths are changed. Both experimental measurements and theoretical simulations show that the amplitude transients depend on the length of the erbium doped fiber (EDF) and the erbium concentration. We show how it may be possible to reduce the gain transients by appropriate design of the EDFA.

Synchronized Turbulent Boundary Layer-Flexible Structure by Sound and Transient Shock Wave

Acoustic and turbulent boundary-layer flow loadings over a flexible structure are used to study the spatial-temporal dynamics of the response of the structure. The stability of the spatial phase synchronization and desynchronization by an active external force is investigated from time series with an array of coupled transducers on the structure. In the synchronous state, the structural phase is locked, which leads to the formation of spatial patterns while the amplitude peaks exhibit chaotic behaviors. Large-amplitude, spatially symmetric loading is superimposed on broadband, but in the desynchronized state, the spectrum broadens and the phase space is lost. The resulting pattern bears a striking resemblance to phase turbulence. The transition is achieved by using a low-power external actuator to trigger broadband behaviors from the knowledge of the external acoustic load, inducing synchronization. The changes are made favorably and efficiently to alter the frequency distribution of power, not the total power level. Before synchronization effects are seen, the panel response to the turbulent boundary-layer loading is discontinuously spatiotemporally correlated. The stability develops from different competing wavelengths; the spatial scale is significantly shorter than when forced with the superimposed external sound. When the external sound level decreases and the synchronized phases are lost, changes in the character of the spectra can be linked to the occurrence of spatial phase transition. These changes can develop broadband response. Synchronized wall pressure loading on a fuselage structural panel induced by turbulent boundary layer and by traveling transient shock wave has been observed in flight. Results from two flight tests are discussed.

Monolithic crystalline multijunction solar cell development and analysis at the US Air Force research laboratory

As satellite payload electrical power system requirements continue to grow, satellite systems employing flat panel arrays have reached limits set by either on-orbit dynamics that limit the size and shape of the deployed array, mass constraints set by the launch vehicle, or by the limits set by the volume constraints of the launch shroud. This has caused several satellite programs to approach power margin limits early in the design cycle, and to either compromise on satellite capabilities or perform costly redesigns. A very leveraging parameter for raising satellite power levels and reducing costs is the efficiency of the solar cells employed by satellite systems. State of the art efficiencies have reached 26.5% efficiency at load, and 30.1% for prototype cells, and solar arrays using GaAs based multijunction solar cells have achieved deployed solar array power densities of 70 W/kg and stowed volume power densities of 8 kW/m 3. A simplified approach to the unwieldy dark current electrical analysis of multijunction solar cells has been developed, correlated with the performance of dual and triple junction solar cells, and explains ideality factors and reverse saturation currents that appear large. It was found that introducing a fourth junction with modest performance could raise the efficiency of multijunction solar cells to 31.5% efficiency at load, raise total power levels to 22 kW, raise the power densities to 100 W/kg and 9 kW/m 3 with no impact to the configuration or operation of satellite solar arrays.

Large area, ultra-high voltage 4H-SiC p-i-n rectifiers

This paper reports the design, fabrication and high temperature characteristics of 1 mm/sup 2/, 4 mm/sup 2/ and 9 mm/sup 2/ 4H-SiC p-i-n rectifiers with 6 kV, 5 kV, and 10 kV blocking voltage, respectively. These results were obtained from two lots in an effort to increase the total power levels on such rectifiers. An innovative design utilizing a highly doped p-type epitaxial anode layer and junction termination extension (JTE) were used in order to realize good on-state as well as stable blocking characteristics. For the 1 mm/sup 2/ and 4 mm/sup 2/ rectifier, a forward voltage drop of less than 5 V was observed at 500 A/cm/sup 2/ and the peak reverse recovery current shows a modest 50% increase in the 25/spl deg/C to 225/spl deg/C temperature range. On the 10 kV, 9 mm/sup 2/ rectifier, a forward voltage drop of less than 4.8 V was observed at 100 A/cm/sup 2/ in the entire 25/spl deg/C to 200/spl deg/C temperature range. For this device, the reverse recovery characteristics show a modest 110% increase in the peak reverse recovery current from 25/spl deg/C to 200/spl deg/C. A dramatically low Q/sub rr/ of 3.8 /spl mu/C was obtained at a forward current density of 220 A/cm/sup 2/ at 200/spl deg/C for this ultra high voltage rectifier. These devices show that more than three orders of magnitude reduction in reverse recovery charge is obtained in 4H-SiC rectifiers as compared to comparable Si rectifiers.

Characterization of the noise emitted by a washing-machine due to the pump

The noise sources during the pump operation of a washing machine are: the electric motor, the water–air impulsion, and the structural radiation of the pump-housing, hose, and cabinet. The determination of the sound power level under different working conditions let us identify that the noise emitted by the cabinet vibration was the more noticeable, being irrelevant the noise emitted by the other elements. In order to know which part of the cabinet is the noisiest, the standard ISO-TR 7849 was applied to calculate the contribution of the noise emitted by the structural radiation of each part of the cabinet to the total sound power level. This experimental procedure relates the noise radiated by a structure with its vibration velocity, and it was found that the kick plate was the more relevant element. Once the noise transmission paths have been characterized, the proposals to reduce noise are focused on a new design of the kick plate to make it more flexible and the modification of the join zone of the pump to the kick plate to reduce the force transmitted between both elements. (To be presented in Spanish.)

Sound power radiated from an inverter-driven induction motor: experimental investigation

The effects of various inverter strategies, switching frequency, random modulation levels and motor speeds on the radiated noise of a 2.2 kW induction motor with and without load were examined by measuring the sound power spectrum, rather than the sound pressure spectrum at a single point in space. Results show that the sound power level due to the aerodynamic and mechanical noise increases at a rate of 12 dB per doubling of the motor speed. For an ideal, almost purely sinusoidal supply, electromagnetic noise dominates at low motor speeds. For a PWM inverter drive, the electromagnetic noise due to the switching harmonics could dominate the total sound power level at low motor speeds; however, the effects of switching harmonics appear to be insignificant at high motor speeds where the noise due to the fundamental frequency is dominant. At high speeds, the variation of sound power level with load is small, whereas at low speeds the total sound power level normally increases due to the low-frequency component.

Core and edge confinement studies with different heating methods in JET

A detailed comparison of core and edge confinement with different heating methods - NBI and ICRH - has been carried out in the ELMy H mode regime in JET with the Gas Box divertor. Transport in the core and characteristics of the edge pedestal have been assessed in discharges at 2.0 MA/2.6-2.7 T at a total input power level of 11-12 MW. The thermal core confinement has been found to be higher by about 10% in ICRH dominated discharges. Although this difference is well within the uncertainties of the thermal confinement estimation, it has been consistently found in similar experiments in the past and it may be related to the more peaked power deposition provided by ICRH. Local transport analysis carried out with the TRANSP code indicates that, independently of the NBI versus ICRH mix, ion conduction losses are the dominant energy loss channel. In contrast to previous experiments, the gas flow and density of NBI and ICRH discharges have been closely matched. In these conditions it has been found that both types of heating yield similar values of edge density and temperature and produce similar ELMs. The fact that the edge fast ion concentration can be varied from roughly 0.4% up to 4% without producing significant changes in the edge pedestal parameters is an indication that fast ions do not always play a dominant role in the edge stabilization between ELMs, especially in discharges with strong gas fuelling.

Gender differences in autonomic cardiovascular regulation: spectral, hormonal, and hemodynamic indexes.

The autonomic nervous system drives variability in heart rate, vascular tone, cardiac ejection, and arterial pressure, but gender differences in autonomic regulation of the latter three parameters are not well documented. In addition to mean values, we used spectral analysis to calculate variability in arterial pressure, heart rate (R-R interval, RRI), stroke volume, and total peripheral resistance (TPR) and measured circulating levels of catecholamines and pancreatic polypeptide in two groups of 25 +/- 1.2-yr-old, healthy men and healthy follicular-phase women (40 total subjects, 10 men and 10 women per group). Group 1 subjects were studied supine, before and after beta- and muscarinic autonomic blockades, administered singly and together on separate days of study. Group 2 subjects were studied supine and drug free with the additional measurement of skin perfusion. In the unblocked state, we found that circulating levels of epinephrine and total spectral power of stroke volume, TPR, and skin perfusion ranged from two to six times greater in men than in women. The difference (men > women) in spectral power of TPR was maintained after beta- and muscarinic blockades, suggesting that the greater oscillations of vascular resistance in men may be alpha-adrenergically mediated. Men exhibited muscarinic buffering of mean TPR whereas women exhibited beta-adrenergic buffering of mean TPR as well as TPR and heart rate oscillations. Women had a greater distribution of RRI power in the breathing frequency range and a less negative slope of ln RRI power vs. ln frequency, both indicators that parasympathetic stimuli were the dominant influence on women's heart rate variability. The results of our study suggest a predominance of sympathetic vascular regulation in men compared with a dominant parasympathetic influence on heart rate regulation in women.

Clinical Investigation of a True Color Scanning Laser Ophthalmoscope

To show true color scanning laser ophthalmoscope (SLO) images produced by simultaneously imaging the retina with red, green, and blue lasers. Low-power red, green, and blue lasers were combined using fiber optics. By rapidly pulsing the lasers, each point on the fundus is illuminated by the 3 colors in quick succession, with the total power level being similar to that from a single laser. The reflected light is then decoded to extract the red, green, and blue color information and the true color fundus image is displayed live on a computer monitor. Comparison was made between the color SLO images from 5 patients and their digitized fundus photographs. The background fundus and retinal vasculature showed a similar appearance. The SLO gave better quality information in patients with ocular histoplasmosis, macular dystrophy, and optic disc drusen. By operating the color SLO in the indirect mode, macular edema could be clearly seen as lines and ridges surrounding the fovea. The color SLO offers all the advantages of the present commercially available monochromatic device, with the added advantage of true color representation of the fundus without increasing either imaging time or the level of exposure.

The three-dimensional power distribution control in load following of the heating reactor

A new optimizing objective (three-dimensional power distribution control) for the load-following problem in nuclear reactor is presented. To realize such an objective, a combination of Harmonic Synthesis Method and Nodal Method has been practiced on the numeric calculation for optimizing problem on the 200 MW Heating Reactor, in which the control rods serve as the only control variables. In contrast, most of the load-following problems have been solved under a one-dimensional neutron model. And it seems that such a model is not suitable for the reactor core whose power was controlled only by control rods. In this case, the control rod causes a strong absorption of neutron in a local area thus makes the radial power distribution play a much more important role in the load-following process. As the 3-dimensional model is used and the corresponding method is performed, both of the total power level and power distribution are controlled well. For example, the power peak-factor is lower about 4% than that with one-dimensional method.

Statistical methods used for code-to-code comparisons in the OECD/NRC PWR MSLB benchmark

The ongoing pressurized water reactor (PWR) main steam line break (MSLB) benchmark problem, sponsored by the Office for Economic Cooperation and Development (OECD), the United States Nuclear Regulatory Commission (US NRC), and the Pennsylvania State University (PSU) consists of three exercises, whose combined purpose is to verify the capability of system codes to analyze complex transients with coupled core/plant interactions; to test fully the 3D neutronics/thermal-hydraulic coupling; and to evaluate discrepancies between the predictions of coupled codes in best-estimate transient simulations. Exercise two is intended to test core response to imposed system thermal-hydraulic conditions. For this exercise, the participants are provided with transient boundary conditions and two cross-section libraries. Results are submitted for six steady-state cases and two transient scenarios. The boundary conditions, the details for each case, and the output requested are described in the final specifications for the benchmark problem. To fully analyze the data for comparison in the final report, a suite of statistical methods has been developed, to serve as a reference in the absence of experimental data. A corrected arithmetical mean and standard deviation are calculated for all data types: single-value parameters, 1D axial distributions, 2D radial distributions, and time histories. Each participant's deviation from the mean and a corresponding figure-of-merit are reported for the purposes of comparison and discussion. Selected mean values and standard deviations are presented in this paper for several parameters at specific points of interest: for the initial steady-state 2, at hot-full power, radial and axial power distributions are presented, along with effective multiplication factor, power peaking factors, and axial offset. For the snapshot taken at the time of highest return-to-power in transient Scenario 2, parameters presented include axial and radial power distributions, total and fission power levels, power peaking factors, and axial offset. Additionally, some features of the time histories for total power and fission power in Scenario 2 are presented and discussed.

Linear Approximation Method for Minimising SRS Effect in All-Optical WDM Fiber Optic Systems

A novel “Linear Approximation Method (LAM)” has been developed and suggested for the estimation of optical powers to be launched at different wavelength channels to minimise the variation in the system performance at different wavelength channels due to Stimulated Raman Scattering (SRS) in Wavelength Division Multiplexed (WDM) fiber optic systems. A 2000 km long point-to-point all-optical WDM fiber optic link having sixteen channels (each channel has a data rate of 2.5 Gbits/sec) with inter-channel separation of 1nm has been simulated to study the effectiveness of the LAM. The efficiency of LAM has also been examined for different inter-amplifier spacing and different levels of total optical power launched into the simulated system.