This paper discusses the lessons learned from analysis of the Moderate Resolution Imaging Spectroradiometer (MODIS) Land-Surface Temperature/Emissivity (LST) products in the current (V4) and previous ...versions, and presents eight new refinements for V5 product generation executive code (PGE16) and the test results with real Terra and Aqua MODIS data. The major refinements include considering surface elevation when using the MODIS cloudmask product, removal of temporal averaging in the 1 km daily level-3 LST product, removal of cloud-contaminated LSTs in level-3 LST products, and the refinements for the day/night LST algorithm. These refinements significantly improved the spatial coverage of LSTs, especially in highland regions, and the accuracy and stability of the MODIS LST products. Comparisons between V5 LSTs and in-situ values in 47 clear-sky cases (in the LST range from −
10
°C to 58
°C and atmospheric column water vapor range from 0.4 to 3.5 cm) indicate that the accuracy of the MODIS LST product is better than 1 K in most cases (39 out of 47) and the root of mean squares of differences is less than 0.7 K for all 47 cases or 0.5 K for all but the 8 cases apparently with heavy aerosol loadings. Emissivities retrieved by the day/night algorithm are well compared to the surface emissivity spectra measured by a sun-shadow method in two field campaigns. The time series of V5 MODIS LST product over two sites (Lake Tahoe in California and Namco lake in Tibet) in 2003 are evaluated, showing that the quantity and quality of MODIS LST products depend on clear-sky conditions because of the inherent limitation of the thermal infrared remote sensing.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Adaptive remeshing finite element model is used for the prediction of material behavior and temperature histories in friction stir welding (FSW). Then, Monte Carlo method with nucleation in every MC ...step is used for the simulation of the grain growth in FSW. In addition, the process of dynamic recrystallization which results in the nucleation of new grains has been modeled. The model is validated by comparison of both experiments and numerical results from the literature. The width of the stirring zone has been estimated by monitoring the movements of the traced material particles and by identifying the region containing dynamically recrystallized fine grains. The inner border of the heat-affected zone has been determined by monitoring the material flow, while the outer border has been identified by monitoring the average grain size as a function of the lateral distance from the weld. The effect of two FSW process parameters, tool rotational speed and tool shoulder diameter, is investigated. An increase in either of these two parameters has been found to increase the overall grain size as well as the width of the welding zones.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Temperature significantly influence the dynamic behavior of granite.•Density variation (within 5%) can be ignored during thermal treatment.•Wave velocity and Young’s modulus decreases as temperature ...increases monotonously.•Energy absorption ability varies as temperature increases with its maximum at 400°C.
A systemic understanding of the thermal effects on the dynamic behavior of granite is significant to thermal engineering applications such as waste disposal engineering and underground coal gasification. In the present study, scanning electron microscope (SEM) tests were carried out to evaluate the thermal effects on the geophysical properties of granite. The results show that the density decreases slightly as the temperature increases from 25°C to 400°C but that it decreases sharply as the temperature increases further to our maximum tested temperature of 800°C. The defect rate increases slightly as temperature increases from 25°C to 400°C and then increases sharply as the temperature further increases to 800°C. Next, ultrasonic wave tests were performed to evaluate the thermal effects on the wave velocity and P-wave modulus. The results show that both the wave velocity and P-wave modulus decrease sharply and linearly below the temperature of 400°C, before deceasing nonlinearly as the temperature increases to 800°C. Finally, split Hopkinson pressure bar (SHPB) tests were adopted to investigate the thermal and loading rate coupling effects. The results show that the dynamic strength decreases linearly as temperature increases but increases as the impact pressure increases. However, the dynamic energy absorption capacity increases below 400°C but then decreases as the temperature increases to 800°C. The thermal effects on energy absorption capacity are more obvious for granite under a smaller impact pressure.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper presents the procedure and results of the radiance-based validation approach for the Moderate Resolution Imaging Spectroradiometer (MODIS) Land-Surface Temperature (LST) product. Surface ...emissivity spectra were retrieved by a sun-shadow method from surface-leaving radiance spectra measured with a thermal infrared (TIR) spectroradiometer in the 3.5-14 µm spectral region under sunshine and sun-shadow conditions. By using the measured surface emissivity spectrum and atmospheric profiles obtained by radiosonde balloons, and the LST values at validation sites in the V5 MODIS level-2 LST products, radiative transfer simulations were made with the MODTRAN4 code to calculate the top-of-atmosphere (TOA) radiance values in MODIS band 31 (L31). By adjusting the LST input values in the simulations to match the calculated L31 values to the MODIS measured radiance (MOD L31) values, MOD L31 inverted LSTs can be obtained. The MODIS LST product was validated by comparison to the values of the MOD L31 inverted LSTs. This approach compares well with the conventional temperature-based approach. The results of the radiance-based validation indicate that the accuracy of the MODIS LST product is better than 1 K in most cases, including lake, vegetation and soil sites in clear-sky conditions. The errors in the split-window retrieved LSTs may be larger in bare soil sites and highly heterogeneous sites due to large uncertainties in surface emissivities. The results of the radiance-based validation also reveal the weakness of the split-window algorithm used for the generation of the MODIS LST product in two situations: one in cases where LSTs are larger than the air temperature at the surface level (T
s-air
) by more than 16 K and the columnar water vapour (cwv) is larger than 1.5 cm, and another in cases under the influence of thin cirrus clouds or heavy aerosol loadings. These two situations were not considered in the development of the current MODIS LST algorithm.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
The role of mitochondria in tumorigenesis has regained much attention as it could dysregulate cellular energetics, oxidative stress and apoptosis. However, the role of mitochondria in different grade ...gliomasis still unknown. This study aimed to identify mitochondrial DNA (mtDNA) sequence variations that could possibly affect the mitochondrial functions and also the oxidative stress status. Three different grades of human glioma cell lines and a normal human astrocyte cell line were cultured
and tested for oxidative stress biomarkers. Relative oxidative stress level, mitochondria activity, and mitochondrial mass were determined by live cell imaging with confocal laser scanning microscope using CM-H
DCFDA, MitoTracker Green, and MitoTracker Orange stains. The entire mitochondrial genome was sequenced using the AffymetrixGeneChip Human Mitochondrial Resequencing Array 2.0. The mitochondrial sequence variations were subjected to phylogenetic haplogroup assessment and pathogenicity of the mutations were predicted using pMUT and PolyPhen2. The Grade II astrocytoma cells showed increased oxidative stress wherea high level of 8-OHdG and oxidative stress indicator were observed. Simultaneously, Grade II and III glioma cells showed relatively poor mitochondria functions and increased number of mutations in the coding region of the mtDNA which could be due to high levels of oxidative stress in these cells. These non-synonymous mtDNA sequence variations were predicted to be pathogenic and could possibly lead to protein dysfunction, leading to oxidative phosphorylation (OXPHOS) impairment, mitochondria dysfunction and could create a vicious cycle of oxidative stress. The Grade IV cells had no missense mutation but preserved intact mitochondria and excellent antioxidant defense mechanisms thus ensuring better survival. In conclusion, Grade II and III glioma cells demonstrated coding region mtDNA mutations, leading to mitochondrial dysfunction and higher oxidative stress.
Rehabilitation is the process of treating post-stroke consequences. Impaired limbs are considered the common outcomes of stroke, which require a professional therapist to rehabilitate the impaired ...limbs and restore fully or partially its function. Due to the shortage in the number of therapists and other considerations, researchers have been working on developing robots that have the ability to perform the rehabilitation process. During the last two decades, different robots were invented to help in rehabilitation procedures. This paper explains the types of rehabilitation treatments and robot classifications. In addition, a few examples of well-known rehabilitation robots will be explained in terms of their efficiency and controlling mechanisms.
•Learning anxiety demonstrated a direct association with learning motivation.•Learning anxiety has also been found to be positively associated with mathematical problem-solving.•Mathematical ...reasoning was positively associated with learning anxiety.•Mathematical reasoning was also found to be positively associated with learning motivation and mathematical problem-solving.•The mediation role of mathematical problem solving was positive associated with learning anxiety and learning motivation.
Mathematical problem solving stands as a fundamental aspect of 21st-century skills. Extensive educational studies have substantiated the cultivation of this competency, illustrating that exploring specific predictors and related variables can offer valuable insights for its enhancement. The study investigated how solving mathematical problems acts as a mediator between motivation for learning, anxiety about learning, and mathematical reasoning. A total of 345 primary school students participated in this study, responding to online questionnaires. Structural equation modelling was applied for data analysis, revealing satisfactory construct validity and instrument reliability. The findings highlighted a positive relationship between learning anxiety and mathematical reasoning, indicating their predictive role in improving learning motivation. In addition, the research identified mathematical problem solving as a mediator, playing a crucial role in reducing learning anxiety and fostering increased learning motivation. These outcomes have significant implications, underscoring the need to understand the intricate interaction between learning anxiety, mathematical reasoning, and motivation. This understanding could facilitate the development of targeted interventions and support systems, fostering a conducive learning environment that enhances student participation and academic achievement.
Full text
Available for:
IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Humidification is one of the most important factors for the operation of proton exchange membrane fuel cell (PEMFC). To maintain the membrane at hydrated state, plenty of water is needed for the ...state-of-the-art of PEMFC technology, especially in large power applications or long time operation. A condenser is introduced to separate liquid water from the air outlet for air self-sufficient in water of the stack in this study. The condensed temperature at the outlet of the condenser and water recovered amount for air self-sufficient in water are investigated theoretically and experimentally. It is shown that the condensed temperature for air self-sufficient in water is irrelevant with the working current of the stack. When the condenser outlet temperature was above the theoretical line, recovery water was not sufficient for the air humidification. On the contrary, it is sufficient while the temperature was below the theoretical line. It is also shown that when the moisture is sufficiently cooled, large amount water can be separated from the outlet gas, and it increased almost linearly with the time. With the introduction of the condenser, the recovered amount of water can easily satisfy the air self-sufficient in water by condensing the outlet gas to a proper temperature.
► We introduce a condenser to separate liquid water from the air outlet in the stack. ► The mechanism of air self-sufficient in water by condensing gas is presented. ► The condensed temperature and water recovered amount are investigated. ► An experiment is present to validate simplicity and feasibility of the criterion. ► The criterion for air humidification is used for choosing the condenser.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper presents an evaluation of the Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) thermal infrared bands and the status of land surface temperature (LST) ...version-3 standard products retrieved from Terra MODIS data. The accuracy of daily MODIS LST products has been validated in more than 20 clear-sky cases with in situ measurement data collected in field campaigns in 2000-2002. The MODIS LST accuracy is better than 1°C in the range from −10 to 50°C. Refinements and improvements were made to the new version of MODIS LST product generation executive code. Using both Terra and Aqua MODIS data for LST retrieval improves the quality of the LST product and the diurnal feature in the product due to better temporal, spatial and angular coverage of clear-sky observations.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
PDF
