scholarly journals Effect of Mechanical Ventilation on the Thermal Offset of Pyranometers during Cloud-Free Summer Conditions

2017 ◽  
Vol 34 (5) ◽  
pp. 1155-1173 ◽  
Author(s):  
G. Sanchez ◽  
A. Serrano ◽  
M. L. Cancillo
Keyword(s):  
Mechanical Ventilation ◽  
Solar Radiation ◽  
Solar Zenith Angle ◽  
Large Range ◽  
Absolute Value ◽  
Operational Conditions ◽  
Global Irradiance ◽  
Diffuse Irradiance ◽  
The Impact ◽  
Radiation Measurements

AbstractThermal offset is a significant source of uncertainty for solar radiation measurements. This study assesses the influence of mechanical ventilation on the daytime thermal offset of pyranometers. Toward this goal, an intensive unprecedented campaign of measurements was conducted in Badajoz, Spain, during four selected summer days under cloud-free conditions, covering a large range of solar zenith angle, irradiance, and temperature. Three leading manufacturers participated in the campaign, providing secondary standard pyranometers and compatible ventilation units. The thermal offset was experimentally measured following the capping methodology. A total of 372 capping events were conducted, the largest number ever reported in the literature. Each pyranometer was tested under different operational conditions (with/without ventilation and measuring global/diffuse irradiance). Results show that mechanical ventilation generally reduces the thermal offset. The magnitude of this reduction is different for each pyranometer model and depends on whether the instrument is shadowed (for measuring diffuse irradiance) or not (for measuring global irradiance). Mechanical ventilation tends to homogenize the temperature around the pyranometer and therefore reduces the impact of environmental conditions on the thermal offset. CMP11 and SPP pyranometers show notable tendencies in the thermal offset even when mechanical ventilation is applied. The Dutton et al. model, which aimed to correct the daytime thermal offset, is evaluated. Results show this model performs well for the SPP pyranometer but underestimates the absolute value of thermal offset for the CMP11 and SR20 pyranometers.

scholarly journals Correcting Daytime Thermal Offset in Unventilated Pyranometers

2015 ◽  
Vol 32 (11) ◽  
pp. 2088-2099 ◽  
Author(s):  
A. Serrano ◽  
G. Sanchez ◽  
M. L. Cancillo
Keyword(s):  
Solar Radiation ◽  
Coefficient Of Determination ◽  
Mean Bias Error ◽  
Bias Error ◽  
General Validity ◽  
Absolute Value ◽  
Complex Models ◽  
Independent Variable ◽  
Source Of Error ◽  
Radiation Measurements

AbstractA main source of error in solar radiation measurements is the thermal offset inherent to pyranometers. Despite acknowledgment of its importance, its correction has been widely ignored for several decades. This neglect may have caused a generalized underestimation in solar radiation measurements. This study focuses on the correction of this error in solar irradiance measurements. For this aim a plethora of correction models built as a linear combination of several environmental variables related to the ambient temperature and to the incoming radiation were proposed. The models are fitted to experimental measurements obtained during capping events and, finally, their performance is evaluated and compared. The main results indicate that models with only one independent variable moderately correct the thermal offset error. These simple models are useful when no additional instrumentation other than the pyranometer is available. On the other hand, the more complex models show the best performance, with a coefficient of determination R2 over 0.8, an RMSE under 2 W m−2, and an absolute value of mean bias error (MBE) under 0.5 W m−2. Additionally, these models are used to study the differences between nighttime and daytime correction, revealing the unsuitability of using nighttime-fitted models to correct the daytime thermal offset. The general validity of the models is tested by their application to two different pyranometers. Results indicate that, whereas the factors involved in the best-performing models are the same, the values of the loading coefficients differ and therefore must be specifically calculated for each pyranometer.

scholarly journals Characterisation of <i>J</i>(O<sup>1</sup>D) at Cape Grim 2000–2005

2014 ◽  
Vol 14 (12) ◽  
pp. 18389-18419 ◽  
Author(s):  
S. R. Wilson
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
Wave Radiation ◽  
Total Column Ozone ◽  
Photolysis Rates ◽  
The Individual ◽  
The Impact ◽  
Ozone Column ◽  
Radiation Measurements ◽  
Cape Grim

Abstract. Estimates of the rate of production of excited oxygen atoms due to the photolysis of ozone J(O1D) have been derived from radiation measurements carried out at Cape Grim, Tasmania (40.6° S, 144.7° E). These estimates agree well with measurements made during SOAPEX-II and with model estimates of clear sky photolysis rates. Observations spanning 2000–2005 have been used to quantify the impact of season, cloud and ozone column amount. The annual cycle of J(O1D) has been investigated via monthly means. These means show an inter-annual variation (monthly standard deviation) of 9%, but in midsummer and midwinter this reduces to 3–4%. Factors dependent upon solar zenith angle and satellite derived total ozone column explain 87% of the observed signal variation of the individual measurements. The impact of total column ozone, expressed as a Radiation Amplification Factor (RAF), is found to be ~1.45, in agreement with model estimates. This ozone dependence explains 20% of the variation observed at medium solar zenith angles (30–50°). The impact of clouds results in a median reduction of 14% in J(O1D) for the same solar zenith angle range. At all solar zenith angles less than 50° approximately 10% of measurements show enhanced J(O1D) due to cloud scattering and this fraction climbs to 25% at higher solar angles. Including estimates of cloudiness derived from Long Wave Radiation measurements resulted in a statistically significant fit to observations but the quality of the fit did not increase significantly as measured by the reduced R2.

scholarly journals Global and diffuse solar radiant exposures at Pone

MAUSAM ◽  
2021 ◽  
Vol 51 (4) ◽  
pp. 349-358
Author(s):  
R. R. SHENDE ◽  
V. R. CHIVATE
Keyword(s):  
Atmospheric Transmission ◽  
Rainfall Distribution ◽  
Monsoon Period ◽  
Global Irradiance ◽  
Radiation Data ◽  
Diffuse Irradiance ◽  
Radiation Measurements

Radiation measurements are being carried out at Pune since 1957. The radiation data for the period 1986-90 are studied here with reference to general sky condition and rainfall distribution. Global irradiances show a decrease of about 5 per cent over the last four decades, The diffuse irradiation contributes about 23 per cent to the global irradiance during winter months, Its proportion increases to more than 70 per cent during the monsoon period. The specific rainfall distribution affects both global and diffuse irradiances but in opposite directions, The diffuse irradiance shows increases as the atmospheric transmission decreases, However, the changes found have not become statistically highly significant as yet.

scholarly journals Characterisation of <i>J</i>(O<sup>1</sup>D) at Cape Grim 2000–2005

2015 ◽  
Vol 15 (13) ◽  
pp. 7337-7349 ◽  
Author(s):  
S. R. Wilson
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
Wave Radiation ◽  
Total Column Ozone ◽  
Photolysis Rates ◽  
Column Ozone ◽  
The Impact ◽  
Radiation Measurements ◽  
Total Column ◽  
Cape Grim

Abstract. Estimates of the rate of production of excited oxygen atoms due to the photolysis of ozone (J(O1D)) have been derived from radiation measurements carried out at Cape Grim, Tasmania (40.6° S, 144.7° E). The individual measurements have a total uncertainty of 16 % (1σ). These estimates agree well with model estimates of clear-sky photolysis rates. Observations spanning 2000–2005 have been used to quantify the impact of season, clouds and ozone column amount. The annual cycle of J(O1D) has been investigated via monthly means. These means show an interannual variation (monthly standard deviation) of 9 %, but in midsummer and midwinter this reduces to 3–5 %. Variations in solar zenith angle and total column ozone explain 86 % of the observed variability in the measured photolysis rates. The impact of total column ozone, expressed as a radiation amplification factor (RAF), is found to be ~ 1.53, in agreement with model estimates. This ozone dependence explains 20 % of the variation observed at medium solar zenith angles (30–50°). The impact of clouds results in a median reduction of 30 % in J(O1D) for the same solar zenith angle range. Including estimates of cloudiness derived from long-wave radiation measurements resulted in a statistically significant fit to observations, but the quality of the fit did not increase significantly as measured by the adjusted R2.

scholarly journals The impact of IFRS-based accounting standards on earnings management: evidence from Malaysia

2016 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Yosra Makni Fourati ◽  
Rania Chakroun Ghorbel
Keyword(s):  
Earnings Management ◽  
Financial Reporting ◽  
Emerging Market ◽  
Accounting Standards ◽  
Absolute Value ◽  
Financial Reporting Standards ◽  
Ifrs Adoption ◽  
Earning Quality ◽  
The Impact ◽  
Different Levels

This study aims to examine the consequences of International Financial Reporting Standards (IFRS) convergence in an emerging market. More specifically, we investigate whether the adoption of the new set of accounting standards in Malaysia is associated with lower earnings management. Using a sample of 3,340 firm-year observations across three reporting periods with different levels of IFRS adoption, we provide evidence that IFRS convergence improves earning quality. In particular, we find a significant decrease in the absolute value of discretionary acccruals in the partial IFRS-convergence period (2007-2011), whereas this effect is restrictive after the complete IFRS- implementation.

scholarly journals Photocatalytic-Fenton Process under Simulated Solar Radiation Promoted by a Suitable Catalyst Selection

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 885
Author(s):  
Aida M. Díez ◽  
Helen E. Valencia ◽  
Maria Meledina ◽  
Joachim Mayer ◽  
Yury V. Kolen'ko
Keyword(s):  
Methylene Blue ◽  
Solar Radiation ◽  
Water Scarcity ◽  
Published Data ◽  
Fenton Process ◽  
Optimal Conditions ◽  
Operational Conditions ◽  
The Future ◽  
Simulated Solar Radiation ◽  
Catalyst Selection

Considering water scarcity, photo-based processes have been presented as a depollution technique, which should be optimized in order to be applied in the future. For that, the addition of an active photocatalyst and the usage of solar radiation are mandatory steps. Thus, Fe3O4–SiO2–TiO2 was synthesized, and its performance was evaluated using simulated solar radiation and methylene blue as a model pollutant. Under optimal conditions, 86% degradation was attained in 1 h. These results were compared to recent published data, and the better performance can be attributed to both the operational conditions selection and the higher photocatalyst activity. Indeed, Fe3O4–SiO2–TiO2 was physico-chemically characterized with techniques such as XRD, N2 isotherms, spectrophotometry, FTIR, electrochemical assays and TEM.

scholarly journals Lower peripheral blood Toll-like receptor 3 expression is associated with an unfavorable outcome in severe COVID-19 patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria Clara Saad Menezes ◽  
Alicia Dudy Müller Veiga ◽  
Thais Martins de Lima ◽  
Suely Kunimi Kubo Ariga ◽  
Hermes Vieira Barbeiro ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Peripheral Blood ◽  
World Health ◽  
Control Group ◽  
Pyrin Domain ◽  
Peripheral Blood Gene Expression ◽  
Severe Group ◽  
Health Organization ◽  
The Impact

AbstractThe role of innate immunity in COVID-19 is not completely understood. Therefore, this study explored the impact of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection on the expression of Pattern Recognition Receptors (PRRs) in peripheral blood cells and their correlated cytokines. Seventy-nine patients with severe COVID-19 on admission, according to World Health Organization (WHO) classification, were divided into two groups: patients who needed mechanical ventilation and/or deceased (SEVERE, n = 50) and patients who used supplementary oxygen but not mechanical ventilation and survived (MILD, n = 29); a control group (CONTROL, n = 17) was also enrolled. In the peripheral blood, gene expression (mRNA) of Toll-like receptors (TLRs) 3, 4, 7, 8, and 9, retinoic-acid inducible gene I (RIGI), NOD-like receptor family pyrin domain containing 3 (NLRP3), interferon alpha (IFN-α), interferon beta (IFN-β), interferon gamma (IFN-γ), interferon lambda (IFN-λ), pro-interleukin(IL)-1β (pro-IL-1β), and IL-18 was determined on admission, between 5–9 days, and between 10–15 days. Circulating cytokines in plasma were also measured. When compared to the COVID-19 MILD group, the COVID-19 SEVERE group had lower expression of TLR3 and overexpression of TLR4.

scholarly journals 375. COVID 19 infection in a Massachusetts community hospital

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S257-S258
Author(s):  
Raul Davaro ◽  
alwyn rapose
Keyword(s):  
Intensive Care Unit ◽  
Mechanical Ventilation ◽  
Intensive Care ◽  
Essential Hypertension ◽  
Severe Acute Respiratory Syndrome ◽  
High Mortality ◽  
Case Series ◽  
World Health ◽  
Minimal Risk ◽  
The Impact

Abstract Background The ongoing pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections has led to 105690 cases and 7647 deaths in Massachusetts as of June 16. Methods The study was conducted at Saint Vincent Hospital, an academic health medical center in Worcester, Massachusetts. The institutional review board approved this case series as minimal-risk research using data collected for routine clinical practice and waived the requirement for informed consent. All consecutive patients who were sufficiently medically ill to require hospital admission with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by positive result on polymerase chain reaction testing of a nasopharyngeal sample were included. Results A total of 109 consecutive patients with COVID 19 were admitted between March 15 and May 31. Sixty one percent were men, the mean age of the cohort was 67. Forty one patients (37%) were transferred from nursing homes. Twenty seven patients died (24%) and the majority of the dead patients were men (62%). Fifty one patients (46%) required admission to the medical intensive care unit and 34 necessitated mechanical ventilation, twenty two patients on mechanical ventilation died (63%). The most common co-morbidities were essential hypertension (65%), obesity (60%), diabetes (33%), chronic kidney disease (22%), morbid obesity (11%), congestive heart failure (16%) and COPD (14%). Five patients required hemodialysis. Fifty five patients received hydroxychloroquine, 24 received tocilizumab, 20 received convalescent plasma and 16 received remdesivir. COVID 19 appeared in China in late 2019 and was declared a pandemic by the World Health Organization on March 11, 2020. Our study showed a high mortality in patients requiring mechanical ventilation (43%) as opposed to those who did not (5.7%). Hypertension, diabetes and obesity were highly prevalent in this aging population. Our cohort was too small to explore the impact of treatment with remdesivir, tocilizumab or convalescent plasma. Conclusion In this cohort obesity, diabetes and essential hypertension are risk factors associated with high mortality. Patients admitted to the intensive care unit who need mechanical ventilation have a mortality approaching 50 %. Disclosures All Authors: No reported disclosures

scholarly journals The Impact of Intervention-Related Risk Factors on the Risk of Ventilator-Associated Pneumonia Is High in a Neurosurgical Intensive Care Unit

2020 ◽  
Vol 41 (S1) ◽  
pp. s407-s409
Author(s):  
Ksenia Ershova ◽  
Oleg Khomenko ◽  
Olga Ershova ◽  
Ivan Savin ◽  
Natalia Kurdumova ◽  
...  
Keyword(s):  
Risk Factors ◽  
Mechanical Ventilation ◽  
Negative Slope ◽  
Infection Prevention And Control ◽  
Ventilator Associated Pneumonia ◽  
Related Factors ◽  
Icu Patients ◽  
The Impact ◽  
Adf Test ◽  
Over Time

Background: Ventilator-associated pneumonia (VAP) represents the highest burden among all healthcare-associated infections (HAIs), with a particularly high rate in patients in neurosurgical ICUs. Numerous VAP risk factors have been identified to provide a basis for preventive measures. However, the impact of individual factors on the risk of VAP is unclear. The goal of this study was to evaluate the dynamics of various VAP risk factors given the continuously declining prevalence of VAP in our neurosurgical ICU. Methods: This prospective cohort unit-based study included neurosurgical patients who stayed in the ICU >48 consecutive hours in 2011 through 2018. The infection prevention and control (IPC) program was implemented in 2010 and underwent changes to adopt best practices over time. We used a 2008 CDC definition for VAP. The dynamics of VAP risk factors was considered a time series and was checked for stationarity using theAugmented Dickey-Fuller test (ADF) test. The data were censored when a risk factor was present during and after VAP episodes. Results: In total, 2,957 ICU patients were included in the study, 476 of whom had VAP. Average annual prevalence of VAP decreased from 15.8 per 100 ICU patients in 2011 to 9.5 per 100 ICU patients in 2018 (Welch t test P value = 7.7e-16). The fitted linear model showed negative slope (Fig. 1). During a study period we observed substantial changes in some risk factors and no changes in others. Namely, we detected a decrease in the use of anxiolytics and antibiotics, decreased days on mechanical ventilation, and a lower rate of intestinal dysfunction, all of which were nonstationary processes with a declining trend (ADF testP > .05) (Fig. 2). However, there were no changes over time in such factors as average age, comorbidity index, level of consciousness, gender, and proportion of patients with brain trauma (Fig. 2). Conclusions: Our evidence-based IPC program was effective in lowering the prevalence of VAP and demonstrated which individual measures contributed to this improvement. By following the dynamics of known VAP risk factors over time, we found that their association with declining VAP prevalence varies significantly. Intervention-related factors (ie, use of antibiotics, anxiolytics and mechanical ventilation, and a rate of intestinal dysfunction) demonstrated significant reduction, and patient-related factors (ie, age, sex, comorbidity, etc) remained unchanged. Thus, according to the discriminative model, the intervention-related factors contributed more to the overall risk of VAP than did patient-related factors, and their reduction was associated with a decrease in VAP prevalence in our neurosurgical ICU.Funding: NoneDisclosures: None

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