Measurement Period Research Articles

Patient reported outcome measures (PROMs) as primary and secondary outcomes in total hip and knee arthroplasty randomized controlled trials: a systematic review.

Significant heterogeneity exists regarding patient reported outcome measures (PROMs) used in total hip (THA) and knee (TKA) arthroplasty randomized controlled trials (RCTs). This study investigates the PROMs used as primary and secondary outcomes in contemporary arthroplasty RCTs. A literature search identified THA and TKA RCTs that were published in top ten impact factor orthopaedic journals from 2017 to 2021. Screening identified 241 trials: 76 THA, 157 TKA, and eight combined. Data were extracted to identify PROMs utilized as either primary or secondary outcomes and the time period of measurement. Visual Analog Scale (VAS) Pain was the most reported primary PROM in THA (9.2%) and TKA (22.9%) trials. This was followed by Numeric Rating Scale (NRS) Pain (7.9%) and the Harris Hip score (6.6%) in THA trials and NRS Pain (4.5%) and the Knee Society score (4.5%) in TKA trials. Many THA (37.0%) and TKA (52.1%) trials did not clearly specify primary outcome time points. Only pain scales were reported at time points less than one week, while various joint-specific functional outcomes were reported at later time points. As secondary outcomes, the Harris Hip score (28.9%) was most common in THA trials and the Knee Society score (26.1%) was most common in TKA trials. Indeterminate primary or secondary outcomes were reported in 18.2% of studies. Contemporary THA and TKA trials exhibit heterogeneity of PROMs as study outcomes after the first postoperative week. Our findings highlight the need for consensus in PROM reporting and better methodological reporting to improve the interpretability of RCT outcomes. CRD42022337255.

EV Charging Scheduling Under Demand Charge: A Block Model Predictive Control Approach

This paper studies the online scheduling of electric vehicle charging by a service provider subject to a demand charge in a distribution system. Demand charge imposes a penalty on the peak power consumption over each billing period, representing a substantial cost for the service provider with a large number of clients. Because the demand charge is calculated at the end of the billing period, it poses challenges in real-time scheduling when energy demand forecasts are inaccurate, resulting in either overly conservative power consumption or substantial demand charge. We propose a block model predictive control approach that decomposes the demand charge into a sequence of stage costs. Optimality conditions on demand patterns are also presented and analyzed. Numerical simulations demonstrate the efficacy of the proposed approach. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This paper addresses a significant practical problem of minimizing the demand charge on the real-time scheduling of deferrable demands. In particular, we consider a setting where a commercial electric vehicle (EV) charging service provider has to manage the online scheduling of a large number of arriving EVs at a charging facility subject to a maximum charging power constraint and a tariff with the demand charge. A major practical challenge is to balance the tradeoff between maximizing profit in scheduling as much EV charging as possible and the need to minimize penalty on the peak charging power. We propose a model predictive control strategy that decomposes the overall demand charge into a sequence of terminal costs. Also addressed is the practical constraint arising from the mismatched EV charging decision period and the power measurement period used to compute the demand charge. Using real data collected at the Adaptive Charging Network (ACN) testbed in simulations, the proposed approach yields 8-12% improvement in operational profit over existing benchmarks, while it has yet been tested in actual charging systems. In the future research, we will address the charging scheduling under demand charge over multiple charging stations.

Noise and PM2.5 levels in children's park adjacent to airport

Background: Sanuki Kodomo-no-Kuni Children's park adjacent to Takamatsu airport is a facility where visitors can watch airplanes take off and land up close and learn about science and technology. However, because it is not a school facility, the hygienic conditions such as noise and PM2.5 levels are not well known despite the current situation where many infants and elementary school students use this facility. Method: Noise and PM2.5 levels were measured at a point in the park 170 m from the runway center. Rsults: Three takeoffs and three landings were made during the measurement period. Instantaneous noise levels of 92.5 to 96.5 dB(A) were recorded during takeoff and 79.9 to 82.2 dB(A) during landing. The PM2.5 level every 30 minutes was 8 μg/m3 at the beginning of the measurement, but 21 μg/m3 was measured at the end, and a trend of increasing PM2.5 levels over time was observed. Conclusion: Noise levels during takeoffs and landings were instantaneous but high. Since previous studies have reported health effects of chronic exposure to aircraft noise, including misbehaviours in young children, memory loss in school children, increased birth rate of low birthweight infants, and hearing loss due to chronic exposure. It was considered desirable to avoid excessive exposure to aviation noise.

A high durable and conductive Mg(OH)2-filled PP/PE composite membrane for alkaline water electrolysis

Design and synthesis of a low-cost, high-durable, and conductive membrane are paramount in reducing energy losses for alkaline water electrolysis (AWE), which has emerged as a promising technology for green hydrogen production. In this study, we utilize Mg(OH)2 particles to fill the pores of a low-cost polypropylene/polyethylene (PP/PE) membrane, thereby reducing gas crossover and enhancing conductivity. This leads to the preparation of a Mg(OH)2-PP/PE composite membrane. When equipped in a flow-type AWE electrolyzer, this composite membrane exhibits a voltage of 1.93 V at a current density of 0.5 A cm−2 over a 100 h measurement period, which is superior to the commercial polyphenylene sulfide (PPS) membrane's voltage of 2.69 V. Furthermore, the 5000 h stability test, without any conductivity loss in the membrane, further confirms its high stability. The successful design of this composite membrane provides a new approach for high-performance AWE.

Effect of Benthic Flux on the Nutrient Dynamics of Bottom Water during Stratification in an Artificial Brackish Lake

In semi-closed coastal brackish systems, the stratification of the water column due to the interaction between freshwater and seawater can lead to a reduction in the dissolved oxygen (DO) levels in the bottom layers, consequently affecting the benthic nutrient flux and causing the degradation in water quality. We performed in situ investigations using a benthic lander to examine changes in the sediment oxygen demand (SOD) and benthic nutrient flux during the development of stratification in the downstream area of an artificially constructed brackish lake. During each measurement period, the temperature and salinity of the water column showed vertically stable stratification. The potential energy anomaly was 88.1–125.7 J/m3, with the stratification intensity strengthening gradually over the measurement period. The concentration of DO in bottom waters gradually decreased as the stratification of the water intensified and the temperature increased, establishing hypoxic conditions. As the stratification intensified, the SOD decreased with the DO concentration in bottom waters, while the benthic fluxes of NH4-N and PO4-P exhibited an opposite effect. When the effect of offshore water (introduced through a sluice gate) was insignificant, the SOD contributed 33% of the net loss of DO below the pycnocline. During this period, the benthic NH4-N and PO4-P fluxes were estimated to contribute 55% and 87% to the net fluxes in NH4-N and PO4-P, respectively, in the water column below the pycnocline. The benthic NH4-N and PO4-P fluxes resulted in excess phosphorus in the bottom water. When the inflow of seawater through the sluice gate was sufficient, the flow in the upstream direction of the bottom layer moved phosphorus-rich bottom water downstream, which is important for algal growth in the middle-upstream region.

Increased atmospheric PM2.5 events due to open waste burning in Qaanaaq, Greenland, summer of 2022

AbstractHigh levels of particulate matter (PM) are relevant to severe air pollution and can adversely impact human health. Maintaining healthy air quality for the residents of the Arctic region is essential to satisfy the no‐one‐left‐behind policy of the Sustainable Development Goals (SDGs) by the United Nations. In this study, we installed a PM2.5 measurement system in Qaanaaq, Greenland, and obtained the first continuous PM2.5 measurements from July 20, 2022 to August 13, 2022. We observed several increased PM2.5 events; relatively high PM2.5 levels persisted from August 8, 2022. On the same day, visible black smoke emitted from the Qaanaaq dump site originated from open waste burning. By confirming less transboundary air pollution contributions from remote aerosol source regions to Qaanaaq during the measurement period using NOAA's HYSPLIT backward trajectory analysis and NASA's MERRA‐2 aerosol re‐analysis, we confirmed that the increased PM2.5 was primarily due to local open waste burning with less contributions from transboundary air pollution. However, small contributions from biomass burning outside Greenland were plausible during the early measurement period. Additionally, NOAA's HYSPLIT dispersion calculations suggested possible aerosol depositions from local open waste burning to nearby sea areas, such as Baffin Bay. Although the hourly mean PM2.5 mass concentration was not alarmingly high during the measurement period, future studies should incorporate longer‐term continuous PM2.5 measurements along with other atmospheric chemical analyses to identify possible local air pollution sources in detail to ensure clean ambient air for the future in the Arctic. Our study provides quantitative evidence of the impact of open waste burning on air quality at a study site in Greenland, which could be crucial in developing air quality policies for this region in the Arctic.

Achieving Energy Self-Sufficiency in a Dormitory Building: An Experimental Analysis of a PV–AWHP-ERV Integrated System

In this study, we investigated the performance of air-to-water heat pump (AWHP) and energy recovery ventilator (ERV) systems combined with photovoltaics (PV) to achieve the energy independence of a dormitory building and conducted an analysis of the energy independence rate and economic feasibility by using energy storage devices. Our data were collected for 5 months from July to November, and the building energy load, energy consumption, and system performance were derived by measuring the PV power generation, purchase, sales volume, AWHP inlet and outlet water temperature, and ERV outdoor, supply, and exhaust temperature. When analyzing representative days, the PV–AWHP integrated system achieved an energy efficiency ratio (EER) of 4.49 and a coefficient of performance (COP) of 2.27. Even when the generated electrical energy exceeds 100% of the electricity consumption, the energy self-sufficiency rate remains at 24% due to the imbalance between energy consumption and production. The monthly average energy self-sufficiency rate changed significantly during the measurement period, from 20.27% in November to 57.95% in September, highlighting the importance of energy storage for self-reliance. When using a 4 kWp solar power system and 4 kWh and 8 kWh batteries, the annual energy self-sufficiency rate would increase to 67.43% and 86.98%, respectively, and our economic analysis showed it would take 16.5 years and more than 20 years, respectively, to become profitable compared to the operation of an AWHP system alone.

Estimating soil N2O emissions induced by organic and inorganic fertilizer inputs using a Tier-2, regression-based meta-analytic approach for U.S. agricultural lands

Consistent methods are essential for generating country and region-specific estimates of greenhouse gas (GHG) emissions used for reporting and policymaking. The estimates of direct N2O emissions from U.S. agricultural soils have primarily relied on the use of emission factors (EFs, Tier-1) and process-based models (Tier-3). However, Tier-1 estimates are relatively crude while Tier-3 calculations can be costly. This work addressed this gap by developing a Tier-2, regression-based approach by leveraging a meta-database containing 1883 field N2O observations together with environmental and management covariates from 139 studies. Our results estimated higher monthly soil N2O emissions (N2Om, kg N/ha) during the growing season (0.38) than the fallow period (0.15), highlighting the importance of considering measurement periods when utilizing meta-databases for analyzing N2O drivers. Significantly different N2Om were found for tillage practices (conventional > no-till: 0.42 > 0.27), fertilizer type (liquid > solid manure: 0.55 > 0.32), and soil texture (fine > coarse: 0.36 > 0.22). The comparisons of the influence of crop type and rotation, water management, and soil order on N2O emissions are complicated by regional data availability and interactions among different factors. Additionally, the finding that N2O emissions reported based on area (N2Om), N input rate (EF), or yield can alter treatment rankings underscores the need to establish transparent criteria for rewarding or discouraging regionally-based management practices using N2O metrics. Finally, we show how General Linear Models (GLMs) can be used to estimate country and regional Tier-2 N2Om using a suite of covariates. Our GLMs identified tillage, water management, N input type and rate, soil properties, and elevation as the most influential covariates for the conterminous U.S. The limited accuracy of regional-scale GLMs, however, suggests the need to further improve the quality and availability of GHG and covariate data through concerted efforts in data collection.

Development of a Follow-Up Measure to Ensure Complete Screening for Colorectal Cancer

The current quality performance measure for colorectal cancer (CRC) screening is limited to initial screening. Despite low rates, there is no measure for appropriate follow-up with colonoscopy after receipt of an abnormal result of a stool-based screening test (SBT) for CRC. A quality performance measure is needed. To develop and test a quality performance measure for follow-up colonoscopy within 6 months of an abnormal result of an SBT for CRC. This retrospective quality improvement study examined data from January 1, 2016, to December 31, 2020, with 2018 plus 6 months of follow-up as the primary measurement period to verify performance rates, specify a potential measure, and test for validity, reliability, and feasibility. The Optum Labs Data Warehouse (OLDW), a deidentified database of health care claims and clinical data, was accessed. The OLDW contains longitudinal health information on enrollees and patients, representing a diverse mixture of ages and geographic regions across the US. For the database study, adults from 38 health care organizations (HCOs) aged 50 to 75 years who completed an initial CRC SBT with an abnormal result were observed to determine follow-up colonoscopy rates within 6 months. Rates were stratified by race, ethnicity, sex, insurance, and test modality. Three HCOs participated in the feasibility field testing. Data were analyzed from June 1, 2022, to May 31, 2023. The primary outcome consisted of follow-up colonoscopy rates following an abnormal SBT result for CRC. Reliability statistics were also calculated across HCOs, race, ethnicity, and measurement year. Among 20 581 adults (48.6% men and 51.4% women; 307 [1.5%] Asian, 492 [7.2%] Black, 644 [3.1%] Hispanic, and 17 705 [86.0%] White; mean [SD] age, 63.6 [7.1] years) in 38 health systems, 47.9% had a follow-up colonoscopy following an abnormal SBT result for CRC within 6 months. There was significant variation between HCOs. Notably, significantly fewer Black patients (37.1% [95% CI, 34.6%-39.5%]) and patients with Medicare (49.2% [95% CI, 47.7%-50.6%]) or Medicaid (39.2% [95% CI, 36.3%-42.1%]) insurance received a follow-up colonoscopy. A quality performance measure that tracks rates of follow-up within 6 months of an abnormal SBT result was observed to be feasible, valid, and reliable, with a median reliability statistic between HCOs of 94.5% (range, 74.3%-99.7%). The findings of this observational study of 20 581 adults suggest that a measure of follow-up colonoscopy within defined periods after an abnormal result of an SBT test for CRC is warranted based on low current performance rates and would be feasible to collect by health systems and produce valid, reliable results.

Changes in the discharge regime of Finnish rivers

Study regionFinland divided into three subregions, each representing different environmental conditions. Study focusThis study investigates long-term changes in unregulated river discharge. Trends in high- and low-flow event volumes, magnitudes, timings, and frequencies are analysed across 36 gauging stations in 19 watershed areas from 1911 to 2021. The average measurement period for discharge in the stations is 60 years, with over 765,000 daily records examined statistically. New hydrological insights for the regionHigh-flow events show advancing timings and decreasing magnitudes, notably in the coastal region and less so in the north. These events, occurring from 6 to 68 days earlier in 21 stations, now in the late winter and early spring, align with increasing spring low-flow volumes. On a monthly scale, a trend of rising volume magnitude is observed in late autumn, winter, and early spring, especially in Northern Finland's rivers. High flows during autumn and winter occur 30 to 60 days later in 8 stations. Changes in the monthly mean volumes were found in 30 stations, suggesting a redistribution of annual volumes across a broader time period, while the overall annual volumes have remained relatively unchanged. This underscores the complexity of hydrological patterns, emphasizing the need to consider total volumes and their temporal distribution in analyses. The findings enhance understanding of current changes and align with findings in the boreal-subarctic area.

Assessing the performance of wind erosion prediction models of RWEQ and SWEEP by direct measurements in an arid region

Wind erosion field studies allow researchers to conduct simulations under natural conditions, thus play a significant role in investigating wind erosion processes. Direct measurements are also used to validate and improve existing erosion models. There is a need to develop sustainable land-use practices and management strategies and to assess potential current and future trends of wind erosion risk in arid and semi-arid regions. This study assessed wind erosion-induced soil losses in 11 different wind cases encountered within the wheat-fallow production system in a semi-arid region of Türkiye between 2017 and 2020 to eliminate the wind erosion threats on soil resources. Direct measurements and two estimation models (RWEQ and SWEEP) were employed to assess soil loss. Grid sampling method and BEST® sediment traps were utilized to measure wind-blown soil in the field directly. Present findings revealed that wind erosion threatened both plots in different seasons. The wheat-cultivated plot was highly susceptible to wind erosion in autumn when winter cereals are sown, while the fallow plot showed susceptibility in spring. Throughout the entire measurement period (3-years), wind erosion-induced soil transportation was measured as 1383 kg ha−1 for fallow plots and 2548 kg ha−1 for wheat-cultivated plots. Model performance was assessed through correlations (r), root mean square error (RMSE) and d-test results. The results demonstrated that the calibrated RWEQ (RWEQcal) model provided reasonably accurate estimates of wind erosion for both fallow and wheat-cultivated lands, with relatively low RMSE values of 0.34 and 0.46, d-test values of 0.26 and 0.27, and correlation coefficients of 0.69 and 0.85, respectively. Model results highlighted the importance of model calibration for local conditions; otherwise, they may produce underestimated and overestimated results.

Air Quality Assessment Based on a Smart Locally CO2 Monitoring System with Validation by a Reference Instrument

This article deals with the development and implementation of a low-cost smart air quality monitoring device. The study aims to develop a simple, efficient, and cheap device for real-time monitoring of Carbon dioxide (CO2) concentration and atmospheric parameters such as temperature (T) and relative humidity (RH). The realized device consists of sensors, a data storage system, a programmable card, and wireless modules for Internet of Things (IoT). It is designed for indoor and outdoor air quality monitoring. Wireless communication between the device and the control PC is ensured by the ZigBee protocol. The MH-Z14A sensor was calibrated according to the manufacturer’s recommendations and then experimentally in the laboratory. A calculation of the CO2 regression line for the devices using the least squares method gave R2 = 0.6889. The slope test using the Student method at a significant coefficient of 1% threshold and 19 degrees of freedom gave t(1%; 19) = 2.539. This illustrates that the result obtained by the realized device has less than a 1% chance of being obtained at random. An investigation was carried out to assess air quality because following the proliferation of pollutants, the normal concentration of atmospheric CO2 (400 ppm) has considerably changed. Thus, the data processed are outdoor concentrations collected in November 2022 in some localities of the Adamawa Region, Cameroon. The average values of CO2 concentration measured in four subdivisions are 497.30 ± 11.32 ppm in Ngaoundéré 1, 481.83 ± 14.90 ppm in Ngaoundéré 2, 568.63 ± 25.03 ppm in Martap and, 624.14 ± 3.96 ppm in Minim. Martap and Minim are among the most important bauxite deposits in the world. These CO2 values higher than the normal atmospheric concentration indicate a moderate Air Quality Index (AQI) in these cities during the measurement period. The designed device is inexpensive, reliable, and appropriate for air quality monitoring.

Determining Appropriate Numbers and Times of Daily Measurements Using GreenFeed System to Estimate Ruminal Methane Emission of Meat Goats.

The study was conducted to determine appropriate numbers and times of daily gas measurements to estimate total daily methane (CH4) emission of meat goats using a GreenFeed system (GFS). A replicated 4 (four measurement protocols) × 4 (four periods) Latin square design was employed with 16 Boer wethers in a confinement pen setting. Measurement protocols entailed three (G-3T; 0600-0700, 1400-1500, and 2200-2300 h), four (G-4T; 0700-0800, 1300-1400, 1900-2000, and 0100-0200 h), and six (G-6T; 0800-0900, 1200-1300, 1600-1700, 2000-2100, 0000-0100, and 0400-0500 h) times for daily measurement periods in GFS. The fourth protocol was continuous measurement over 24 h with animals in an open-circuit respiration calorimetry system (CS). Oat hay was given in individual feeders, and a small predetermined quantity of a pelleted concentrate supplement (bait) was dispensed by the GFS or manually offered for the CS. Overall, total dry matter (DM) intake (614, 625, 635, and 577 g/day for CS, G-3T, G-4T, and G-6T, respectively; SEM = 13.9) and digestible DM intake (359, 368, 374, and 320 CS, G-3T, G-4T, and G-6T, respectively; SEM = 15.9) were lower for CS than for G-3T, G-4T, and G-6T (p < 0.05), but these variables were not different among the GFS protocols. There was a significant (p < 0.001) effect of measurement protocol on CH4 emission in g/day (11.1, 25.6, 27.3, and 26.7 for CS, G-3T, G-4T, and G-6T, respectively; SEM = 1.11), g/kg DM intake (19.3, 46.4, 43.9, and 42.4 for CS, G-3T, G-4T, and G-6T, respectively; SEM = 2.03), and g/kg body weight (0.49, 1.11, 1.18, and 1.16 for CS, G-3T, G-4T, and G-6T, respectively; SEM = 0.052), with values being much lower for CS than for G-3T, G-4T and G-6T. Conversely, CH4 emission was similar among the GFS protocols despite differences in the time and number of daily visits (2.03, 2.76, and 3.75 visits for G-3T, G-4T, and G-6T, respectively; SEM = 0.114; p < 0.001). Pearson correlation (r) analysis indicated a moderate to high (p < 0.05) correlation between CS and G-3T (r = 0.62 for CH4 in g/day and r = 0.59 for CH4 in g/kg BW), CS and G-4T (r = 0.67 for CH4 in g/day and r = 0.76 for CH4 in g/kg BW), and CS and G-6T (r = 0.70 for CH4 in g/day and r = 0.75 for CH4 in g/kg BW). However, the correlation coefficient for CH4 in g/kg DM intake was low between CS and G-3T (r = 0.11) and CS and G-6T (r = 0.31) but slightly greater between CS and G-4T (r = 0.47). In conclusion, the results suggest that CH4 emissions using GFS in a confinement setting were greater compared with the CS in goats, but CH4-emission estimation using the GFS correlated with the CH4 emission in the CS system with a stronger relationship for the four times of daily measurements.

Drought effects on soil greenhouse gas fluxes in a boreal and a temperate forest

AbstractChanging water regimes (e.g. drought) have unknown long-term consequences on the stability and resilience of soil microorganisms who determine much of the carbon and nitrogen exchange between the biosphere and atmosphere. Shifts in their activity could feedback into ongoing climate change. In this study, we explored soil drought effects on soil greenhouse gas (GHG; CO2, CH4, N2O) fluxes over time in two sites: a boreal, coniferous forest in Finland (Hyytiälä) and a temperate, broadleaf forest in Austria (Rosalia). Topsoil moisture and topsoil temperature data were used to identify soil drought events, defined as when soil moisture is below the soil moisture at the permanent wilting point. Data over multiple years from automated GHG flux chambers installed on the forest floor were then analyzed using generalized additive models (GAM) to study whether GHG fluxes differed before and after drought events and whether there was an overall, multiyear temporal trend. Results showed CO2 and N2O emissions to be more affected by drought and long-term trends at Hyytiälä with increased CO2 emission and decreased N2O emissions both following drought and over the entire measurement period. CH4 uptake increased at both sites both during non-drought periods and as an overall, multiyear trend and was predominantly affected by soil moisture dynamics. Multiyear trends also suggest an increase in soil temperature in the boreal forest and a decrease in soil moisture in the temperate forest. These findings underline forests as an important sink for CH4, possibly with an increasing rate in a future climate.

Post-fire soil greenhouse gas fluxes in boreal Scots pine forests–Are they affected by surface fires with different severities?

Although forest fires are one of the main natural disturbance types in boreal forests, there is limited information regarding surface fires (dominant in Northern Europe), and how surface fires of different severities could affect post-fire soil greenhouse gas emissions. The results of our study show that fire severity, time since fire and post-fire changes in soil temperature were the main factors driving soil carbon dioxide (CO2) flux (forest floor ecosystem respiration) from burned boreal forest soils. Approximately two hours after the fire, soil CO2 emissions from burned areas were significantly higher compared to pre-fire conditions, and areas with high-severity fires had significantly higher soil CO2 emissions compared to those with low-severity fires. Later (days, months) after the fire, the unburned control areas always had higher soil CO2 emission values compared to burned areas. In the case of methane (CH4), time since fire and post-fire changes in soil temperatures were the main factors driving soil CH4 fluxes. Unburned study areas were sinks of CH4 through the entire measurement period, while immediately after the fire, the burned areas turned from CH4 sink to CH4 source. For nitrous oxide (N2O) measurements, time since fire was the only factor that significantly affected soil N2O fluxes. Shortly after the fire, N2O emissions increased significantly from both low- and high-intensity study plots. Two days after the fire, post-fire soil C and N content decreased in the O-horizon and increased within the first 5 cm of the soil mineral layer, and the trend was visible both in low- and high-severity fire plots. Samples collected four months after the fire, showed similar total soil C and N content as there was before the fire.

Influences of Average Temperature Difference and Measurement Period on Estimation of In Situ Thermal Transmittance of Building Exterior Walls Using the Average Method of ISO 9869-1

Many studies have sought to overcome the two main limitations of the average method of ISO 9869-1—its long test duration and low accuracy. These studies reported that the reliability of the results is dependent on the temperature differences. This consensus was based on the results of studies that measured a few cases with specific temperature differences, and the convergence criteria utilized for the representative thermal transmittance (U-value) were rarely examined. This study analyzed the influence of the average temperature difference and test duration on the convergence characteristics and accuracy of U-value estimation using the average method. Data from a north-facing exterior wall with a theoretical U-value of 0.145 W/m2·K were measured between June 2022 and May 2023. The influences of different measurement conditions were analyzed for cases divided based on four measurement periods and 11 average air temperature differences. The findings show that an accurate U-value can be obtained from 7 days’ worth of measurement data with an average temperature difference of 10 °C or higher and that the improvement in accuracy is minimal under stricter conditions. To achieve a convergence probability of over 90% for temperature differences of 10 °C or greater, the second and third criteria required measurement periods of 7 and 15 days respectively.

Spatio-temporal dynamics of superstructures and vortices in turbulent Rayleigh–Bénard convection

Understanding turbulent thermal convection is essential for modeling many natural phenomena. This study investigates the spatiotemporal dynamics of the vortical structures in the mid-plane of turbulent Rayleigh–Bénard convection in SF6 via experiments. For this, a Rayleigh–Bénard cell of aspect ratio 10 is placed inside a pressure vessel and pressurized up to 1, 1.5, and 2.5 bar in order to reach Rayleigh numbers of Ra = 9.4×105,2.0×106, and 5.5×106, respectively. For all three cases, the Prandtl number is Pr =0.79 and ΔT≈7 K. Then, stereoscopic particle image velocimetry is conducted to measure the three velocity components in the horizontal-mid-plane for 5.78×103 free fall times. For the given aspect ratio, the flow is no longer dominated by the side walls of the cell and turbulent superstructures that show a two-dimensional repetitive organization form. These superstructures show diverse shapes with faster dissipation rates as Ra increases. Out-of-plane vortices are the main feature of the flow. As Ra increases, the number of these vortices also increases, and their size shrinks. However, their total number is almost constant for each Ra through the measurement period. Furthermore, their occurrence is random and does not depend on whether the flow is upward-heated, downward-cooled, or horizontally directed. Vortex tracking was applied to measure lifetime, displacement, and traveled distance of these structures. The relation between lifetime and traveled distance is rather linear. Interestingly, in the vortex centers, the out-of-plane momentum transport is larger in comparison to the bulk flow. Therefore, these vortices will play a major role in the heat transport in such flows.

ФОРМИРОВАНИЕ ПОЛОЖИТЕЛЬНЫХ АНОМАЛИЙ ТЕМПЕРАТУРЫ ПОВЕРХНОСТИ ЧЕРНОГО МОРЯ

Based on the satellite data at the points of a high-resolution regular grid for the period from 2008 to 2021, positive anomalies of the sea surface temperature (SST) in the northern Black Sea and off the southwestern coast of Crimea have been identified. It has been shown that there are vast areas with an exceeding of SST over the mean for the measurement period up to 4-5 and 5-6°C and a monthly total area (for example, in May 2018) about 200000 and 100000 km2, respectively, in the northern Black Sea. The analysis of available satellite data has led to the conclusion that warm SST anomalies occur mainly in May and October. The maximum (over the entire analyzed period) warm SST anomaly (exceeding 5°C) was reached in May 2012, when its area was 200000 km2. The spatial structure and some statistical characteristics of the identified SST anomalies have been described and analyzed. It has been shown that the typical frequency of vast SST anomalies is at least one case per several years, while they are generated by abnormal heat fluxes on the sea surface with the inflow of anomalously warm river water in shallow areas of the northwestern shelf and spread to the open sea areas due to the horizontal advection of predominantly wind-driven origin. The average annual SST anomalies off the northwestern coast of Crimea and in the northern Black Sea correlate at a level of 0.97.

Transpiration Dynamics of Esparto Grass (Macrochloa tenacissima (L.) Kunth) in a Semi-Arid Mediterranean Climate: Unraveling the Impacts of Pine Competition.

Macrochloa tenacissima (M. tenacissima), or esparto, is a perennial tussock grass that coexists with Pinus halepensis (P. halepensis) in semi-arid Mediterranean woodlands. This research was carried out to explore diurnal transpiration at leaf level in esparto grass under different levels of pine-esparto competition and in contrasting environmental soil water conditions. The measurement period spanned from the summer of 2020 to the spring of 2021. The relationship between transpiration and competition was conducted in open and closed P. halepensis stands, and the type of leaf (green, senescent) and the maturity of the esparto grass were taken into account. We observed a higher control of transpiration in green leaves, and the correlations between the transpiration and pine competition were noted exclusively in this type of leaf. Our results demonstrated a significant impact of pine competitors (closed stands) on the transpiration of esparto grass, particularly during seasons characterized by scenarios of high water demand: the summer drought period and the commencement of the growing and flowering period (spring). Furthermore, our findings revealed a greater response to transpiration in mature bushes compared to young ones under severe water stress, indicating a higher adaptation to drought by esparto as it ages. Although our results confirmed that PAR increased transpiration in all seasons and in both stands, which is attributable to the heliophilia of esparto grass, the site effects on transpiration could also be attributable to competition for water, especially during periods of drought. These results may have important implications for the dynamics and management of these semi-arid mixed woodlands, as well as the planning of reforestation programs aimed at restoring esparto grass formations.

Milk production and nitrogen excretion of grazed dairy cows in response to plantain (Plantago lanceolata) content and lactation season.

The study aimed to quantify milk production and urinary nitrogen (UN) excretion of dairy cows grazing pastures containing varying contents of plantain (Plantago lanceolata) in different seasons, under a typical farm practice. Four pasture treatments: perennial ryegrass (Lolium perenne) - white clover (Trifolium repens) (RGWC), RGWC + low plantain rate, RGWC + medium plantain rate, and RGWC + high plantain rate, were established in four adaptation areas (1 ha each) and 20 experimental plots (800 m2 each), and rotationally grazed by dairy cows over 14 grazing events during two lactation years. In each grazing (8-9 days), 60 or 80 Jersey-Friesian lactation cows were assigned to their pasture treatments, adapted to their pastures over the first six days, then each group of 15 or 20 cows were randomly allocated for grazing in five treatment plots over a two or three-day measurement period. Milk, urine, and faecal samples were collected from individual cows during the measurement period. The pasture treatments did not affect milk production, the yield and composition of milk solids, protein, fat, and lactose. However, cows grazing pastures containing between 17-28% dietary plantain reduced UN concentration by 15-27%, decreased UN excretion by 4-9%, and increased urine volume by 22-40%, compared to grazing the RGWC pasture. The change in UN concentration, and urine volume were associated with plantain proportion in the diet and were greater during late summer and autumn than during early summer. Incorporating 17%-28% dietary plantain with RGWC pastures can reduce the risk of nitrogen losses from pastoral systems, while maintaining the milk production of dairy cows.