384 research outputs found
Evaluation of solar modelling techniques through experiment on a 627 kWp photo-voltaic solar power plant at Edinburgh College—Midlothian Campus, Scotland.
The accuracy and applicability of existing methods of solar resource modelling and solar photovoltaic module performance are investigated in the case of a ground array installation at Edinburgh College, Midlothian Campus, the principal derived quantities consisting of slope irradiation, cell temperature, and cell efficiency. Experimental data were obtained on site through both automated and manual measurements for comparison with the calculated quantities. Results indicate that the horizontal-to-slope conversion models used are extremely accurate, with greater than 99% degree of confidence in the calculated results. Likewise, correlations between measured and calculated cell temperature were very high at up to 94%. Estimations of the cell efficiency and hence module output were less reliable, however, with only one of the models used, for one of the days studied, giving reasonable results. Efficiency values were, however, in the approximately correct range of 15%–20%
Transcatheter versus surgical closure of atrial septum defect: a debate from a developing country
Abstract INTRODUCTION:
This study compares the effectiveness and cost of trans-catheter verses surgical closure of secundum atrial septumdefect (ASD). ASD accounts for 10% of congenital cardiac defects. Trans-catheter closure of secundum ASD is increasingly used as the primary intervention. Surgical repair is advised in a proportion of secundum type defects which are unsuitable for device closure. METHODS:
We reviewed the clinical course of 176 patients who underwent closure of isolated secundum ASD. The patients were assigned to either the device or surgical group depending upon the treatment they received. Successful closure was assessed immediately after the procedure. The following outcomes were studied: mortality, morbidity, hospital stay, and costs. RESULTS:
Ninety five patients were in the surgical group and 81 patients were in the group undergoing device closure. The median age was 14.0 years (range 1.1-61.0) for surgical group and 24.0 years (range 0.5-68.0) for the device group. The mortality in both groups was 0. The procedure success rate was 100% for the surgical group and 96.3% for the device group. The complication rate was 13.7% for surgical group and 7.4% for the device group. The mean length of hospital stay was 5.0 ± 2.7 days for surgical group and 3.0 ± 0.4 days for device group. The procedure cost for surgery was found to be 12.3% lower than that of trans-catheter closure. CONCLUSION:
Successful closure is achieved by both methods. Trans-catheter closure results in lower rate of complication and hospital stay but the cost of the procedure tends to be higher than surgery
Monthly average daily global and diffuse solar radiation based on sunshine duration and clearness index for Brasov, Romania
The main objective of this study is to develop single location appropriate models for the estimation of the monthly average daily global and diffuse horizontal solar radiation for Brasov, Romania. The study focuses particularly on models based on the sunshine duration and clearness index. The data used for the calibration of the models were collected during a period of 4 yr, between November 2008 and October 2012, at the Transilvania University of Brasov. The testing and validation of the models was carried out using data from the online SoDa database for Brasov for the year 2005. Different statistical error tests were applied to evaluate the accuracy of the models. The predicted values are also compared with values from three other known models concerning the global and diffuse solar radiation. A new mixed model was developed for the estimation of monthly average daily global horizontal solar radiation. The data processing was performed by means of a real-time interface developed with LabVIEW graphical programming language. The parameters taken into account were the relative sunshine, the clearness index, the extraterrestrial radiation, the latitude and the longitude. The methodology is simple and effective and may be applied for any region. Its effectiveness was proven through comparison with global models
Research studies on polymeric effect of indomethacine transdermal films
The objective of this study was to design and evaluate transdermal patches of Indomethacine using HPMC, EC and Eudragit RLPO using solvent casting technique. The in vitro drug release studies were performed by using the USP (paddle type) dissolution list apparatus in 1000 ml of 0.1N HCl (Medium Employed) at 37o C room temperature for an rpm maintained at 100 within a stipulated time interval of 15 minutes. The withdrawn Samples were analyzed by using UV visible spectrophotometer at 268 mm using regent blank. The prepared transdermal patches had undergone physic chemical evaluator parameters such as PMA, PML, swelling index, water vapour transmission rate, film thickness, weight cheek, and folding Endurance and drug content clearance. In vitro dissolution study of drug along with different combination of polymers; i.e. HPMC, EC and Eudragit has been performed; out of which batch B6 shows the best moisture of films and the graph representing the best controlled drug release. As the percentage of ethyl cellulose was reduced the rate of the release of the drug was increased. [Batch B6 > HPMC: EC: Eudragit RLPO - 2:1:2]. Films with batch code B6 shows better stability and suitability. Higuchi’s plot revealed that the predominant Mechanism of drug release was diffusio
Parked Electric Vehicle’s Cabin Temperature Management Using Photovoltaic Powered Ventilation
District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations. Abstract This paper presents how the electric vehicle roof integrated photovoltaic (PV) powered ventilation can be used for controlling the climate of the car. In this work, a fully-functional Renault Zoe electric car has been used to conduct experiments for PV powered ventilation. These experiments have been part of a wider research project of testing electric vehicles of the Edinburgh Napier University's Transport Research Institute. The present work illustrates performance evaluation of electric car ventilation, when roof-mounted PV modules were used to operate DC powered fans for ventilation. It was found that the motor-fan selection for removing the warm air from cabin space is of important (i.e. motor-fan operating points have to be near to the maximum power points of PV modules under varying solar radiation). In this article, experimental results are presented and analysed
Parked electric car's cabin heat management using photovoltaic powered ventilation system
This paper explores the use of electric car roof mounted photovoltaic (PV) powered ventilation for cabin heat management/ventilation. A fully-functional Renault Zoe electric car has been used for performance evaluation of parked electric car ventilation directly powered by PV. This work has been part of a research project of testing electric cars in the urban environment and it has been conducted at the Edinburgh Napier University’s Transport Research Institute. In this work, parked electric car ventilation has been reported, when roof-mounted PV modules were used to operate DC powered fans for ventilation. It has been found that the DC motor-fan selection for removing the hot air from cabin space is of important (i.e. operating characteristics of motor-fan have been very close to the maximum power points locus of the PV modules at different solar insolation). The electric car cabin temperature models with reference to solar radiation have been presented and it will be useful for knowing the parked car cabin temperature variations and designing the car roof mounted PV powered ventilation system. In this paper, performance evaluation of parked electric car’s cabin heat management is presented and analysed. Results from this work will be helpful for designing electric car ventilation system (operating at parking time), when powered by vehicle roof integrated PV modules
COMPARATIVE EFFICACY OF FIVE DIFFERENT BRANDS OF COMMERCIAL NEWCASTLE DISEASE LASOTA VIRUS VACCINES IN BROILERS
Five commercial LaSota strain Newcastle disease (ND) vaccines namely A, B, C, D and E were evaluated for their potency, efficacy, thermostability and influence on productivity in broilers. A 3-log10 difference of EID50 and two-to-eight fold difference of HA activity was found among the various vaccines tested. One hundred and fifty day-old broiler chicks were divided into six equal groups tagged as I, II, III, IV, V and VI. The birds in groups I, II, III, IV and V were actively immunized against ND on days 7 (eye drop method) and 21 (drinking water) using vaccines A, B, C, D and E, respectively. The birds in group VI served as unvaccinated control. The serum HI antibody response to five vaccines was determined 7, 14, 21 and 28 days post-vaccination. Fifteen birds from each group including unvaccinated control were challenged at day 35 with local virulent ND field isolate. The HI serum antibody profile and post-challenge mortality pattern revealed a dose-response relation between the virus content, humoral antibody response and clinical protection. To compare the heat stability, the vaccines were incubated at 4, 25 and 400C for a period of 24 hours. There was no remarkable reduction in HA titer, however slight dips (less than 2 logarithmic units) in EID50 values were found in all the vaccines. All the vaccines caused significant suppression in weight gain, leading to a poor performance in terms of feed conversion ratio (FCR) and European Efficiency Factor (EEF)
Evolution of emission line activity in intermediate mass young stars
We present optical spectra of 45 intermediate mass Herbig Ae/Be stars.
Together with the multi-epoch spectroscopic and photometric data compiled for a
large sample of these stars and ages estimated for individual stars by using
pre-main sequence evolutionary tracks, we have studied the evolution of
emission line activity in them. We find that, on average, the H_alpha emission
line strength decreases with increasing stellar age in HAeBe stars, indicating
that the accretion activity gradually declines during the PMS phase. This would
hint at a relatively long-lived (a few Myr) process being responsible for the
cessation of accretion in Herbig Ae/Be stars. We also find that the accretion
activity in these stars drops substantially by ~ 3 Myr. This is comparable to
the timescale in which most intermediate mass stars are thought to lose their
inner disks, suggesting that inner disks in intermediate mass stars are
dissipated rapidly after the accretion activity has fallen below a certain
level. We, further find a relatively tight correlation between strength of the
emission line and near-infrared excess due to inner disks in HAeBe stars,
indicating that the disks around Herbig Ae/Be stars cannot be entirely passive.
We suggest that this correlation can be understood within the frame work of the
puffed-up inner rim disk models if the radiation from the accretion shock is
also responsible for the disk heating.Comment: 39 pages, accepted for publication in Ap
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