Acceptance Ratio Analysis in Grid-Connected Photovoltaic System: Is There Any Difference Between DC and AC?

2021 ◽  
Vol 30 (1) ◽  
pp. 221-233
Author(s):  
Fatin Azirah Mohd Shukor ◽  
Hedzlin Zainuddin ◽  
Jasrul Jamani Jamian ◽  
Nurmalessa Muhammad ◽  
Farah Liyana Muhammad Khir ◽  
...  
Keyword(s):  
System Performance ◽  
Performance Status ◽  
Photovoltaic System ◽  
Performance Ratio ◽  
Acceptance Test ◽  
Acceptance Ratio ◽  
Percentage Difference ◽  
Ac Power ◽  
Significant Difference ◽  
One Year

The performance status of a grid-connected photovoltaic (GCPV) system is denoted by performance indices, namely performance ratio, capacity factor, and even through power acceptance ratio (AR), as documented in Malaysia Standard (MS) procedures for acceptance test of GCPV testing and commissioning (TNC). Even though AR analysis can be either on the DC or AC side, the MS TNC procedures implemented analysis on the AC side. Therefore, the question arises whether there is any significant difference when using AC AR analysis compared to DC AR analysis in evaluating the system performance. Thus, this paper evaluates the differences between applying DC AR analysis and AC AR analysis in accessing the performance of the ten kWp GCPV system in Malaysia. The AR analytical analysis employed the 2019 one-year historical data of solar irradiance, module temperature, DC power, and AC power. The results demonstrated that the monthly AC AR were consistently lower than DC AR with a percentage difference of approximately 3%. The percentage discrepancy was due to the variation of actual inverter efficiencies compared to the declared constant value by the manufacturer used in the AR prediction model. These findings have verified a significant difference between DC AR analysis and AC AR analysis. Most importantly, this study has highlighted the significance of AC AR analysis compared to DC AR analysis as a tool to evaluate GCPV system performance because AC AR has taken an additional factor into consideration, which is the inverter efficiency variation.

scholarly journals Analysis Corrected Performance Ratio on Photovoltaic Through Four Temperature Cell Model

2018 ◽  
Vol 67 ◽  
pp. 01026
Author(s):  
Rio Agustian Fajarin ◽  
Eko Adhi Setiawan
Keyword(s):  
System Performance ◽  
Cell Model ◽  
Photovoltaic System ◽  
Performance Ratio ◽  
The Real ◽  
Ratio Calculation

To measure the performance of photovoltaic system, performance ratio is a common indicator to used. However, the performance ratio calculation is based on various methods to determine the value of photovoltaic temperature. The modelling used in this research is sandia, Ross and Smokler, Schott and Faiman modeling. Each model have different coefficient values from each others. Thus, each modelling has different performance ratio values that will be compared between others. From this comparison we will get the best modelling that closest to the real conditions.

Risk of venous thromboembolism following surgical treatment of superficial venous incompetence

VASA ◽  
2017 ◽  
Vol 46 (6) ◽  
pp. 484-489 ◽  
Author(s):  
Tom Barker ◽  
Felicity Evison ◽  
Ruth Benson ◽  
Alok Tiwari
Keyword(s):  
Venous Thromboembolism ◽  
Varicose Vein ◽  
Lower Incidence ◽  
Varicose Veins ◽  
Secondary Data ◽  
Foam Sclerotherapy ◽  
Increased Risk ◽  
Significant Difference ◽  
Chi Squared ◽  
One Year

Abstract. Background: The invasive management of varicose veins has a known risk of post-operative deep venous thrombosis and subsequent pulmonary embolism. The aim of this study was to evaluate absolute and relative risk of venous thromboembolism (VTE) following commonly used varicose vein procedures. Patients and methods: A retrospective analysis of secondary data using Hospital Episode Statistics database was performed for all varicose vein procedures performed between 2003 and 2013 and all readmissions for VTE in the same patients within 30 days, 90 days, and one year. Comparison of the incidence of VTEs between procedures was performed using a Pearson’s Chi-squared test. Results: In total, 261,169 varicose vein procedures were performed during the period studied. There were 686 VTEs recorded at 30 days (0.26 % incidence), 884 at 90 days (0.34 % incidence), and 1,246 at one year (0.48 % incidence). The VTE incidence for different procedures was between 0.15–0.35 % at 30 days, 0.26–0.50 % at 90 days, and 0.46–0.58 % at one year. At 30 days there was a significantly lower incidence of VTEs for foam sclerotherapy compared to other procedures (p = 0.01). There was no difference in VTE incidence between procedures at 90 days (p = 0.13) or one year (p = 0.16). Conclusions: Patients undergoing varicose vein procedures have a small but appreciable increased risk of VTE compared to the general population, with the effect persisting at one year. Foam sclerotherapy had a lower incidence of VTE compared to other procedures at 30 days, but this effect did not persist at 90 days or at one year. There was no other significant difference in the incidence of VTE between open, endovenous, and foam sclerotherapy treatments.

Levels of Prothrombin Fragment F1+2 in Patients with Hyperhomocysteinemia and a History of Venous Thromboembolism

1997 ◽  
Vol 78 (05) ◽  
pp. 1327-1331 ◽  
Author(s):  
Paul A Kyrle ◽  
Andreas Stümpflen ◽  
Mirko Hirschl ◽  
Christine Bialonczyk ◽  
Kurt Herkner ◽  
...  
Keyword(s):  
Venous Thromboembolism ◽  
Thrombin Generation ◽  
Oral Anticoagulant Therapy ◽  
Oral Anticoagulants ◽  
Control Group ◽  
Prothrombin Fragment ◽  
Hemostatic System ◽  
Significant Difference ◽  
System Activation ◽  
One Year

SummaryIncreased thrombin generation occurs in many individuals with inherited defects in the antithrombin or protein C anticoagulant pathways and is also seen in patients with thrombosis without a defined clotting abnormality. Hyperhomocysteinemia (H-HC) is an important risk factor of venous thromboembolism (VTE). We prospectively followed 48 patients with H-HC (median age 62 years, range 26-83; 18 males) and 183 patients (median age 50 years, range 18-85; 83 males) without H-HC for a period of up to one year. Prothrombin fragment Fl+2 (Fl+2) was determined in the patient’s plasma as a measure of thrombin generation during and at several time points after discontinuation of secondary thromboprophylaxis with oral anticoagulants. While on anticoagulants, patients with H-HC had significantly higher Fl+2 levels than patients without H-HC (mean 0.52 ± 0.49 nmol/1, median 0.4, range 0.2-2.8, versus 0.36 ± 0.2 nmol/1, median 0.3, range 0.1-2.1; p = 0.02). Three weeks and 3,6,9 and 12 months after discontinuation of oral anticoagulants, up to 20% of the patients with H-HC and 5 to 6% without H-HC had higher Fl+2 levels than a corresponding age- and sex-matched control group. 16% of the patients with H-HC and 4% of the patients without H-HC had either Fl+2 levels above the upper limit of normal controls at least at 2 occasions or (an) elevated Fl+2 level(s) followed by recurrent VTE. No statistical significant difference in the Fl+2 levels was seen between patients with and without H-HC. We conclude that a permanent hemostatic system activation is detectable in a proportion of patients with H-HC after discontinuation of oral anticoagulant therapy following VTE. Furthermore, secondary thromboprophylaxis with conventional doses of oral anticoagulants may not be sufficient to suppress hemostatic system activation in patients with H-HC.

Comparative Study between Endoscopic Aided Septoplasty with Two Handed Technique using Endoholder and Conventional Septoplasty

2020 ◽  
Vol 16 (3) ◽  
Author(s):  
Apar Pokharel ◽  
Naganawalachullu Jaya Prakash Mayya ◽  
Nabin Gautam
Keyword(s):  
Comparative Study ◽  
Nasal Septum ◽  
Deviated Nasal Septum ◽  
Endoscopic Septoplasty ◽  
Septal Surgery ◽  
Significant Difference ◽  
Common Causes ◽  
Prospective Comparative Study ◽  
Evolutionary Step ◽  
One Year

Introduction: Deviated nasal septum is one of the most common causes for the nasal obstruction. The objective of this study is to compare the surgical outcomes in patients undergoing conventional septoplasty and endoscopic septoplasty in the management of deviated nasal septum. Methods:  Prospective comparative study was conducted on 60 patients who presented to the Department of ENT, College of Medical sciences, during a period of one year. The severity of the symptoms was subjectively assessed using NOSE score and objectively assessed using modified Gertner plate. Results: There was significant improvement in functional outcome like NOSE Score and area over the Gertner plate among patients who underwent endoscopic septoplasty. Significant difference in incidence of post-operative nasal synechae and haemorrhage was seen in conventional group compared to endoscopic group. Conclusions: Endoscopic surgery is an evolutionary step towards solving the problems related to deviated nasal septum. It is safe, effective and conservative, alternative to conventional septal surgery.

EVALUTING THE EFFECTS OF EARLY INTERVENTION PROGRAM FOR CHILDREN WITH DEVELOPMENTAL DISABILITIES IN COMMUNITY

2011 ◽  
pp. 70-76
Author(s):  
Keyword(s):  
Social Cognition ◽  
Early Intervention ◽  
Developmental Delay ◽  
Intervention Program ◽  
Language Skills ◽  
Early Intervention Program ◽  
Self Help ◽  
Home Based ◽  
Significant Difference ◽  
One Year

Objectives: To evualate the effects of early intervention program after one year for 33 disabled children in Hue city in 2010. Objects and Methods: Conduct with practical work and assessment on developing levels at different skills of the children with developmental delay under 6 years old who are the objects of the program. Results: With the Portage checklist used as a tool for implementing the intervention at the community and assessing developing skills on Social, Cognition, Motor, Self-help and Language skills for children with developmental delay, there still exists significant difference (p ≤ 0.05) at developing level of all areas in the first assessment (January, 2010) and the second assessment (December, 2010) after 12 months. In comparison among skills of different types of disabilities, there is significant difference of p ≤ 0.05 of social, cognition and language skills in the first assessment and of social, cognition, motor and language skills in the second assessment. Conclusion: Home-based Early Intervention Program for children with developmental delay has achieved lots of progress in improving development skills of the children and enhancing the parents’ abilities in supporting their children at home.

ENHANCEMENT OF PHOTOVOLTAIC SYSTEM PERFORMANCE BASED ON DIFFERENT ARRAY TOPOLOGIES UNDER ‎PARTIAL ‎SHADING CONDITIONS‎

2021 ◽  
Vol 40 (1) ◽  
pp. 49-62
Author(s):  
Abdelrahman M. Mohamed ◽  
Abou-Hashima M. El-Sayed ◽  
Yehia S. Mohamed ◽  
Husam A. Ramadan
Keyword(s):  
System Performance ◽  
Photovoltaic System ◽  
Partial Shading

Renal Phosphate Handling in Antiretroviral-naïve HIV-infected Patients

2020 ◽  
Vol 20 ◽  
Author(s):  
Tewogbade Adeoye Adedeji ◽  
Simeon Adelani. Adebisi ◽  
Nife Olamide Adedeji ◽  
Olusola Akanni Jeje ◽  
Rotimi Samuel Owolabi
Keyword(s):  
Hiv Infection ◽  
Plasma Phosphate ◽  
Cross Sectional ◽  
Phosphate Retention ◽  
Significant Difference ◽  
Immunodeficiency Virus ◽  
Life Threatening ◽  
Moderate Chronic Kidney Disease ◽  
One Year ◽  
Sectional Analysis

Background: Human immunodeficiency virus (HIV) infection impairs renal function, thereby affecting renal phosphate metabolism. Objectives: We prospectively estimated the prevalence of phosphate abnormalities (mild, moderate to life-threatening hypophosphataemia, and hyperphosphataemia) before initiating antiretroviral therapy (ART). Methods: A cross-sectional analysis was performed on 170 consecutive newly diagnosed ART-naïve, HIV-infected patients attending our HIV/AIDS clinics over a period of one year. Fifty (50) screened HIV-negative blood donors were used for comparison (controls). Blood and urine were collected simultaneously for phosphate and creatinine assay to estimate fractional phosphate excretion (FEPi %) and glomerular filtration rate (eGFR). Results: eGFR showed significant difference between patients’ and controls’ medians (47.89ml/min/1.73m2 versus 60ml/min/1.73m2, p <0.001); which denotes a moderate chronic kidney disease in the patients. Of the 170 patients, 78 (45.9%) had normal plasma phosphate (0.6-1.4 mmol/L); 85 (50%) had hyperphosphataemia. Grades 1, 2 and 3 hypophosphataemia was observed in 3 (1.8%), 3 (1.8%), and 1(0.5%) patient(s) respectively. None had grade 4 hypophosphataemia. Overall, the patients had significantly higher median of plasma phosphate than the controls, 1.4 mmol/L (IQR: 1.0 – 2.2) versus 1.1 mmol/L (IQR: 0.3 – 1.6), p <0.001, implying hyperphosphataemia in the patients; significantly lower median urine phosphate than the controls, 1.5 mmol/L (IQR: 0.7 -2.1) versus 8.4 mmol/L (IQR: 3.4 – 16), p <0.001), justifying the hyperphosphataemia is from phosphate retention; but a non-significantly lower median FEPi% than the controls, 0.96 % (IQR: 0.3 -2.2) versus 1.4% (IQR: 1.2 -1.6), p > 0.05. Predictors of FEPi% were age (Odds ratio, OR 0.9, p = 0.009); weight (OR 2.0, p < 0.001); CD4+ cells count predicted urine phosphate among males (p = 0.029). Conclusion: HIV infection likely induces renal insufficiency with reduced renal phosphate clearance. Thus, hyperphosphataemia is highly prevalent, and there is mild to moderate hypophosphataemia but its life-threatening form (grade 4) is rare among ART-naïve HIV patients.

scholarly journals A206 EVOLUTION OF PEDIATRIC AUTOIMMUNE CHOLANGITIS AND PRIMARY SCLEROSING CHOLANGITIS INTO ADULTHOOD

2021 ◽  
Vol 4 (Supplement_1) ◽  
pp. 234-236
Author(s):  
P Willems ◽  
J Hercun ◽  
C Vincent ◽  
F Alvarez
Keyword(s):  
Primary Sclerosing Cholangitis ◽  
Sclerosing Cholangitis ◽  
Response To Treatment ◽  
Similar Proportion ◽  
Autoimmune Cholangitis ◽  
Significant Difference ◽  
One Year ◽  
Liver Tests

Abstract Background The natural history of primary sclerosing cholangitis (PSC) in children seems to differ from PSC in adults. However, studies on this matter have been limited by short follow-up periods and inconsistent classification of patients with autoimmune cholangitis (AIC) (or overlap syndrome). Consequently, it remains unclear if long-term outcomes are affected by the clinical phenotype. Aims The aims of this is study are to describe the long-term evolution of PSC and AIC in a pediatric cohort with extension of follow-up into adulthood and to evaluate the influence of phenotype on clinical outcomes. Methods This is a retrospective study of patients with AIC or PSC followed at CHU-Sainte-Justine, a pediatric referral center in Montreal. All charts between January 1998 and December 2019 were reviewed. Patients were classified as either AIC (duct disease on cholangiography with histological features of autoimmune hepatitis) or PSC (large or small duct disease on cholangiography and/or histology). Extension of follow-up after the age of 18 was done for patients followed at the Centre hospitalier de l’Université de Montréal. Clinical features at diagnosis, response to treatment at one year and liver-related outcomes were compared. Results 40 patients (27 PSC and 13 AIC) were followed for a median time of 71 months (range 2 to 347), with 52.5% followed into adulthood. 70% (28/40) had associated inflammatory bowel disease (IBD) (78% PSC vs 54% AIC; p=0.15). A similar proportion of patients had biopsy-proven significant fibrosis at diagnosis (45% PSC vs 67% AIC; p=0.23). Baseline liver tests were similar in both groups. At diagnosis, all patients were treated with ursodeoxycholic acid. Significantly more patients with AIC (77% AIC vs 30 % PSC; p=0.005) were initially treated with immunosuppressive drugs, without a significant difference in the use of Anti-TNF agents (0% AIC vs 15% PSC; p= 0.12). At one year, 55% (15/27) of patients in the PSC group had normal liver tests versus only 15% (2/13) in the AIC group (p=0.02). During follow-up, more liver-related events (cholangitis, liver transplant and cirrhosis) were reported in the AIC group (HR=3.7 (95% CI: 1.4–10), p=0.01). Abnormal liver tests at one year were a strong predictor of liver-related events during follow-up (HR=8.9(95% CI: 1.2–67.4), p=0.03), while having IBD was not (HR=0.48 (95% CI: 0.15–1.5), p=0.22). 5 patients required liver transplantation with no difference between both groups (8% CAI vs 15% CSP; p=0.53). Conclusions Pediatric patients with AIC and PSC show, at onset, similar stage of liver disease with comparable clinical and biochemical characteristics. However, patients with AIC receive more often immunosuppressive therapy and treatment response is less frequent. AIC is associated with more liver-related events and abnormal liver tests at one year are predictor of bad outcomes. Funding Agencies None

Sign in / Sign up

Export Citation Format

Share Document