Changes in solar activity based on radiocarbon data and climate variations in the interval 8000 - 1000 BC

This work examines the change in the activity of the Sun based on the reconstruction of the heliospheric modulation potential in the time interval 8000 - 1000 BC. Reconstructions of this potential were obtained using radiocarbon data, taking into account the influence of changes in the Earth’s climate. A comparison is made of the variations in the activity of the Sun with the global surface temperature. It is shown that variations in global temperature during this period could be the result of changes in solar activity. So high solar activity could lead to recorded temperature maximums around 7000 and 5300 BC. The drop in temperature in the range 3000-1000BC could be the result of low solar activity.

Rational Construction of Superhydrophobic PDMS/PTW@cotton Fabric for Efficient UV/NIR Light Shielding

Passive daytime radiative cooling (PDRC) material has intrigued increasing attentions with its energy saving potential and smart cloth feature. In this work, PDRC cotton fabric with superhydrophobicity, ultraviolet protection and self-cleaning competency was successful constructed through the deposition chemically-stable potassium titanate whiskers (PTW) and polydimethylsiloxane (PDMS) onto cotton fibers. While featured with ultra-high contact angle of 151.9±0.9 °, the synthesized fabric marked an average temperature drop of ~5.1 ℃, bestowed to its high sunlight reflectivity of 83 % and infrared emissivity of nearly 90 %. On the other hand, real human tests further confirmed the practicality of the modified cotton fabric, with the recorded temperature drops ranged from 3.1~4.7 ℃ under direct sunlight. Such performance elucidated a significant improvement upon PTW/PDMS modification, which outperformed that of pristine cotton fabric. Surmising from these, the synthesized superhydrophobic fabric exhibits advantageous techno-economical index with its excellent performance and simple preparation, therefore manifesting limitless application potential, particularly in outdoor clothing and other facilities.

Centuries of Heat Waves over India during 20th and 21st Century

An assessment of temperature extremes is made for the Indian subcontinent to identify the changes since 1951 to 2015, and for the future climate periods till 2100 for all the 21 CMIP5 (Coupled Model intercomparision Project phase 5) models and the representative concentration pathways RCP4.5 and RCP8.5 were examined for the period from 1 March to 31 May to characterize the heat waves in future climates and mean maximum and mean minimum bias were evaluated for the Indian subcontinent. Later two highest recorded temperature regions were chosen Northwest & Central India (NW&CIN) and only central India (CIN) box and the features of heat waves such as intensity and frequency were evaluated up to 2100. Corresponding temperature predictions from historical runs for the period 1951–2005 of 21 global CMIP model outputs and statistics were performed with the India Meteorological Department (IMD) gridded maximum temperature data for validation. Statistical metrics of BIAS, RMSE and MAE have indicated low BIAS, high correlation and high IOA (Index of Agreement) validating CMIP climate simulations. By analyzing the statistics of all the 21 models with respect to the observational gridded data from IMD came to conclusion that among all the 21 models 5 models were performing well for Indian region and having good index of agreement with IMD. The frequencies of the days having thresholds of 40 ºC, 42 ºC and 45 ºC for the maximum temperature over India during the pre-monsoon are evaluated up to 21st century. All models are showing that the intensity and frequency of heat waves were increasing significantly for both RCP4.5 and RCP8.5. Specifically, the characteristics of heat waves in terms of intensity, duration and area extent are calculated and compared to heat waves of the current climate.

Microclimatic Effects on the Preservation of Finds in the Visitor Centre of the Archaelological Site 1a Imperial Palace Sirmium

For the purpose of this paper, the actual air temperature and air humidity values were monitored in the Visitor Centre of the Archaeological site 1a Imperial Palace Sirmium, designated cultural heritage of exceptional importance. The contamination level of archaeological finds in the site was microbiologically analysed. The findings showed that during the phase of microclimatic monitoring (February–April 2021), air humidity was almost constantly above the levels set by standards and recommendations for museum collections (>60%). The highest levels of air humidity, amounting to 93%, were recorded in February, with daily oscillations of up to 30%; the lowest recorded temperature was 0.3°C, with the maximum daily oscillations of 6°C. Microbiological analysis revealed great diversity in the deterioration level of the finds, which can be attributed to the time lapse between the last conservation and the present. The comparative analysis of microclimatic monitoring and microbiological analysis results identified high levels of relative air humidity as the dominant factor in the increased microbiological contamination of the finds. The findings also pointed to the necessity of continuous microclimatic monitoring during the actual usage of the facility in order to provide the sustainable display and preservation of the finds on the premises.

Metrological Support of Medical Drillings at the Lateral Skull Base

For minimally invasive drilling processes, the temperature development in the drilling ground is of crucial importance for patient safety. To monitor the temperature during drilling, a drill prototype was developed by BREDEMANN ET AL. which can record the drill temperature in parallel to the process and in real time. The measurement principle of the thermistor (temperature sensor) integrated in the drill could be validated. [1] The prototype must be refined for use in the operating room, as the drill does not yet meet all the medical requirements that need to be fulfilled. In further development, the recorded temperature data in particular must be processed and communicated to the surgeon in order to provide added value for the surgical procedure.

Geothermal Assessment of Target Formations Using Recorded Temperature Measurements for the Alberta No. 1 Geothermal Project

The Alberta No. 1 project is a planned power and heat (direct use) geothermal project located within the County of Grande Prairie and Municipal District of Greenview. For the project to successfully produce power and heat on a commercial scale, temperatures of 120 °C are desirable. The produced fluids must also be from highly permeable formations from depths of less than 4500 m. Bottomhole temperature measurements and wireline logs from Alberta’s extensive oil and gas database were used to determine the depths to target formations and temperatures within these formations in the project area. The target formations include the dolomitized carbonate units of Devonian age from the Beaverhill Lake Group to the top of the Precambrian Basement. Permeable Devonian-aged sandstone units such as the Granite Wash Formation are also targets. Results suggest that elevation to the top of the Beaverhill Lake Group range from 3104 m to 4094 m and temperatures at the top of the formation range from 87 °C to 123 °C in the study area. Elevation to the top of the Precambrian Basement ranges from 3205 m to 4223 m and temperatures at the formation top range from 74 °C to 124 °C. Within the area where Alberta No. 1 plans to drill, temperatures close to and exceeding 120 °C are expected within the target formations.

Application of random walk to model temperature in 60 African cities for the 20th century

The 20th century is marked with climate change led by global warming. So far, many models have been applied to analyze the temperature change. However, a simple but interesting model, a random walk is hardly used in his regard. In this study, we use the random walk to model the temperature in the format of random walk that is the conversion of recorded temperature and the real recorded temperature in 60 African cities including 53 capitals for the 20th century. The results show that the random walk can satisfyingly model either temperature in the format of random walk or real recorded temperature although the fitted results from other climate models are unavailable for comparison in these 60 cities. As nothing else besides random numbers is involved in this modelling, the results seem somewhat counter-intuitively.

Piezoelectric Implant Site Preparation: Influence of Handpiece Movements on Temperature Elevation

Piezoelectric devices are widely used in oral surgical procedures, including implant site preparation. However, little is known about the influence of working movement on temperature elevation in bone. The aim of this study was to assess the effects of two different working cycles on temperature elevation during piezoelectric implant site preparation. Sixty osteotomies at a depth of 10 mm were performed on bone blocks of bovine ribs using a piezoelectric tip with external irrigation (IM1s, Mectron Medical Technology, Carasco, Italy). A mechanical positioning device was used to guarantee reproducible working and measuring conditions. Two different working cycles, of 4 and 6 s, respectively, were tested, including both longitudinal and rotational movements. Temperature was recorded in real time with a fiber optic thermometer and applied pressure was maintained under 150 g. For each test, the highest recorded temperature (Tmax) and the mean temperature recorded from 30 s before to 30 s after the highest recorded temperature (T±30) were extrapolated. Tests duration was also recorded. Both Tmax and T±30 were significantly higher in the ‘6 s cycles’ group than the ‘4 s cycles’ group (42.44 ± 7.3 °C vs. 37.24 ± 4.6 °C, p = 0.002; 37.24 ± 4.6 °C vs. 33.30 ± 3.3 °C, p = 0.003). Test duration was also significantly higher using 6 s cycles compared to 4 s cycles (143.17 ± 29.4 s vs. 119.80 ± 36.4 s, p = 0.002). The results of this study indicate that working cycles of 4 s effectively reduce heat generation and working time during piezoelectric implant site preparation.

The Influence of an Additional Sensor on the Microprocessor Temperature

This paper deals with the problem of inserting a temperature sensor in the neighbourhood of a chip to monitor the junction temperature. If the sensor is not in the middle of the heat source, the recorded temperature can be quite different from the chip temperature we are mainly interested in. For the steady state temperature, it is rather easy to introduce a correction factor. For the transient behaviour of the temperature, there is a tremendous difference between the chip and the sensor temperature, which cannot be neglected if the temperature is used as a parameter to change, for example, the clock frequency in order to improve the throughput.

SHAPING OF DUCTILE CAST IRON DEDICATED FOR SLAG LADLE

In industrial conditions, ductile iron was prepared and two molds were made, in which a 600mm thick plate was formed. Filling system for one mold was placed vertically and for the second -horizontally. In order to obtain cooling curves, "S" type thermocouples have been placed in the mold. After cooling the casts, the samples from the fixing points of thermocouples were cut by the trepanning method. In the "vertical" cast sample shrinkage porosity was observed, while in the "horizontal" cast sample no porosity was detected. A significant difference in the recorded temperature in the center of the casts was discovered, indicating a defect in "vertical" cast.