Average Temperature Elevation Research Articles

Utilizations of reaction exothermic heat to compensate the cost of the permanent CO2 sequestration through the geological mineral CO2 carbonation

Many climate change events drive global efforts on CO2 sequestration to reach carbon neutrality. With the help of chemical processes, the novel “geological mineral CO2 carbonation” procedure makes it possible to sequester CO2 quickly and then store it permanently as stable carbonates. The exothermic nature of the mineral carbonation reaction can potentially compensate for the energy consumption during CO2 sequestration. This study mainly addresses a two-dimensional model of the geological mineral CO2 carbonation (herein, the geological formation of peridotite), by which the effects of temperature conditions on the reaction rate and the quantity of the sequestrated CO2 and exothermic heat energy are discussed. Results reveal a typical case of the average temperature elevation of peridotite by over 55 °C (reaching 240 °C) after 2 years. Peridotite's average CO2 sequestration rate in this typical case can achieve 132.62 kg/(year·m³). By changing the injected fluid temperature and the initial peridotite temperature to 110–150 °C, the average CO2 sequestration rate can be increased by 33–43%, obtaining a temperature greater than 150 °C. This heat production from the geological mineral CO2 carbonation can profitably compensate for the energy consumption in the Carbon Capture, Utilization, and Storage projects via the geological mineral CO2 carbonation.

Development of phase change material assisted evacuated tube solar dryer: Investigation of thermal profile, drying characteristics, and functional properties of pumpkin slices

The present work aimed to develop a phase change material-assisted evacuated tube solar dryer (PCM-ETSD) and experiments were performed with and without PCM for drying pumpkin slices. Thermal performance, drying characteristics, and quality attributes were analyzed with and without PCM at different airflow rates: 34.64 kg/h, 51.96 kg/h, and 69.28 kg/h. The average temperature elevation between the ambient and drying chamber was achieved at 29.62 °C to 36.33 °C and 25.64 °C to 28.93 °C without and with PCM-assisted drying respectively. PCM-ETSD extended the drying period by 2 h and maintained the temperature ranges from 50.78 °C to 61.29 °C after sunshine hours. The PCM-ETSD reduced the moisture content of pumpkin slices by 4–5% and 8% more as compared to without PCM and sun drying respectively. Drying rate and effective moisture diffusivity are enhanced with the increase of airflow rate in the drying process and higher without PCM-assisted drying followed by PCM and sun drying. The total phenolic content and total flavonoid content are higher in PCM-assisted drying and continuously decreased with the increases in airflow rate in both drying processes. Antioxidant activity and total carotenoid content are higher in PCM-assisted drying. FTIR analysis confirmed the presence of active functional groups and phenols in dried pumpkin. The inferior color changes were observed in PCM-assisted drying of pumpkin slices. The developed PCM-ETSD could be capable of drying other food commodities on a pilot scale after sunshine with retention of quality attributes.

La Unidad Norte de la Cordillera Blanca y el Cambio Climático

La Cordillera Blanca del Perú es la cadena de montañas glaciares más extensa y alta del planeta en la zona intertropical. Tiene 180 km de largo y una superficie de 470 km² de glaciares. Su constitución geomorfológica la individualiza en varios sectores divididos por profundos valles glaciares o quebradas. El sector más importante de la Cordillera Blanca está ubicado en la parte norte, entre la quebrada de Santa Cruz en su flanco sur y la quebrada Quitaracsa en su flanco norte, que drenan sus aguas al río Santa, teniendo como quebrada intermedia a Los Cedros. Esta gran superficie de territorio de montañas tiene cumbres glaciares entre los 4800 hasta los 6241 msnm, cinco cumbres superiores a los 6000 m, y encierra al famoso nevado Alpamayo, considerado la montaña más bella del planeta. Por efecto de los cambios climáticos, con elevación de temperatura promedio mayor a 0.5 °C entre 1962 y 2016, se ha reducido el área de la superficie glaciar de 105.22 km², calculados con fotografías aéreas de los años 1962-1965, a 71.06 km² al año 2016, estimados en base a imágenes ópticas SPOT, reduciéndose a la vez las reservas hídricas en 34.16 km², con un aporte descendente de agua para los fines de la generación de energía, la agricultura y la industria, afectando el desarrollo futuro de las regiones de Ancash y la Libertad. Las líneas que siguen en el presente artículo se refieren a las principales manifestaciones que se advierten en los glaciares por efecto de los impactos negativos del cambio climático y las correspondientes acciones de adaptación que se vienen dando.

Studying bio-thermal effects at and around MSW dumps using Satellite Remote Sensing and GIS

Estimating negative impacts of MSW dumps on its surrounding environment is the key requirement for any remedial measures. This study has been undertaken to map bio-thermal effects of MSW dumping at and around dumping facilities (non-engineered) using satellite imagery for Faisalabad, Pakistan. Thirty images of Landsat 8 have been selected after validation for the accuracy of their observational details from April 2013 to October 2015. Land Surface Temperature (LST), NDVI, SAVI and MSAVI have been derived from these images through Digital Image Processing (DIP) and have been subjected to spatio-temporal analysis in GIS environment. MSW dump has been found with average temperature elevation of 4.3K and 2.78K from nearby agriculture land and urban settlement respectively. Vegetation health has been used as the bio-indicator of MSW effects and is implemented through NDVI, SAVI, MSAVI. Spatial analyses have been used to mark boundary of bio-thermally affected zone around dumped MSW and measure 700m. Seasonal fluctuations of elevated temperatures and boundary of the bio-thermally affected zones have also been discussed. Based on the direct relation found between vegetation vigor and the level of deterioration within the bio-thermally affected region, use of crops with heavy vigor is recommended to study MSW hazard influence using bio-indicators of vegetation health.

Thermal cataract induced by near infrared radiation (IRR)

PurposeTo estimate the threshold radiant exposure for 1090 nm IRR and the time evolution of lens damage; To determine the temperature time evolution in the eye during the previously found threshold exposure, and the associated heat diffusion; To investigate if 1090 nm IRR induces cataract photochemically considering irradiance exposure time reciprocity.MethodsThe 6‐weeks‐old albino rats were anesthetized intraperitoneally, ten min before exposure. The pupils of both eyes were dilated with tropicamide. Five min after pupil dilation, the animals were unilaterally exposed to 1090 nm IRR within the pupil area. Temperature was recorded with thermocouples placed in the selected positions of the eye. At the planned post‐exposure time, the animal was sacrificed and the lenses were extracted for measurements of forward light scattering and macroscopic imaging.ResultsThe in vivo exposure to 197 W/cm2 1090 nm IRR required a minimum 8 s for cataract induction with a delayed onset of approx 16 h. The same radiant exposure was found to cause a temperature increase of 10°C at the limbus and 26°C close to the retina. The in vivo exposure to 96 W/cm2 1090 nm IRR with exposure time up to 1 h resulted in an average temperature elevation of 7°C at the limbus with the cornea humidified and no significant light scattering was induced one week after exposure.ConclusionsAn in vivo exposure to 197 W/cm2 IRR at 1090 nm within the pupil for 8 s induces cataract with a time delay. This threshold exposure causes a temperature rise of 10°C at the anterior segment of the rat eye. IRR at 1090 nm produces thermal cataract, probably by indirect heat conduction from absorption in tissues surrounding the lens. There is no cataract development given that the limbal temperature increase is below 8ºC.

Simulation of synthetic climate at local scale as a mean to assess the impact of climate change on infrastructures

A global modelling approach for estimating the climate influence on corrosion activity in reinforced concrete is developed. It combines: (a) the identification of statistical properties of climates in various temperate regions, and the development of a synthetic simulator able to reproduce its dominant patterns, (b) the identification of an empirical corrosion activity model, based on the analysis of experimental data, highlighting the respective influence of temperature and humidity. Synthetic simulations combining these two models are carried out. They show the complexity of the interactions, since the influence of temperature and humidity may be adverse, and the interest to describe both random fluctuations at daily scale and at seasonal scale. They confirm that monitoring of corrosion must account for this time variability and propose a way to estimate average corrosion even with measurements which would remain limited to a short period. Synthetic simulations are also used for estimating the influence of a global warming scenario on the corrosion activity. A global increase of about 38% of corrosion activity has been estimated in response to an average temperature elevation of 3°C.

A Nanoparticle-Based Ratiometric and Self-Calibrated Fluorescent Thermometer for Single Living Cells

The homeostasis of body temperature and energy balance is one of the major principles in biology. Nanoscale thermometry of aqueous solutions is a challenging but crucial technique to understand the molecular basis of this essential process. Here, we developed a ratiometric nanothermometer (RNT) for intracellular temperature measurement in real time. Both the thermosensitive fluorophore, β-diketonate chelate europium(III) thenoyltrifluoroacetonate, and the thermoinsensitive fluorophore, rhodamine 101, which was used as a self-reference, are embedded in a polymeric particle that protects the fluorophores from intracellular conditions. The ratiometric measurement of single RNT spots is independent of the displacement of the RNT along the z-axis. The temperature is therefore determined at the location of each RNT under an optical microscope regardless of the dynamic movement of living cells. As a demonstration of the spot-by-spot intracellular thermometry, we successfully followed the temperature change in individual RNT spots in a single cell together with the Ca(2+) burst induced by the Ca(2+) ionophore ionomycin. The temperature increases differently among different spots, implying heterogeneous heat production in the cell. We then show that, in some spots, the temperature gradually decreases, while in others it remains high. The average temperature elevation within a cell is positively correlated to the increase in Ca(2+), suggesting that the activity and/or number of heat sources are dependent on the Ca(2+) concentration.

Targeting accuracy of transcranial magnetic resonance–guided high-intensity focused ultrasound brain therapy: a fresh cadaver model

This work aimed at evaluating the accuracy of MR-guided high-intensity focused ultrasound (MRgHIFU) brain therapy in human cadaver heads. Eighteen heads of fresh human cadavers were removed with a dedicated protocol preventing intracerebral air penetration. The MR images allowed determination of the ultrasonic target: a part of the thalamic nucleus ventralis intermedius implicated in essential tremor. Osseous aberrations were corrected with simulation-based time reversal by using CT data from the heads. The ultrasonic session was performed with a 512-element phased-array transducer system operating at 1 MHz under stereotactic conditions with thermometric real-time MR monitoring performed using a 1.5-T imager. Dissection, imaging, targeting, and planning have validated the feasibility of this human cadaver model. The average temperature elevation measured by proton resonance frequency shift was 7.9°C ± 3°C. Based on MRI data, the accuracy of MRgHIFU is 0.4 ± 1 mm along the right/left axis, 0.7 ± 1.2 mm along the dorsal/ventral axis, and 0.5 ± 2.4 mm in the rostral/caudal axis. Despite its limits (temperature, vascularization), the human cadaver model is effective for studying the accuracy of MRgHIFU brain therapy. With the 1-MHz system investigated here, there is millimetric accuracy.

Reduction of thermal damage in photodynamic therapy by laser irradiation techniques

General application of continuous-wave (CW) laser irradiation modes in photodynamic therapy can cause thermal damage to normal tissues in addition to tumors. A new photodynamic laser therapy system using a pulse irradiation mode was optimized to reduce nonspecific thermal damage. In in vitro tissue specimens, tissue energy deposition rates were measured in three irradiation modes, CW, pulse, and burst-pulse. In addition, methods were tested for reducing variations in laser output and specific wavelength shifts using a thermoelectric cooler and thermistor. The average temperature elevation per 10 J/cm2 was 0.27°C, 0.09°C, and 0.08°C using the three methods, respectively, in pig muscle tissue. Variations in laser output were controlled within ± 0.2%, and specific wavelength shift was limited to ± 3 nm. Thus, optimization of a photodynamic laser system was achieved using a new pulse irradiation mode and controlled laser output to reduce potential thermal damage during conventional CW-based photodynamic therapy.

A comparative study of temperature elevation on human teeth root surfaces during Nd:YAG laser irradiation in root canals

The purpose of this study was to evaluate the temperatures on the root surfaces during Nd:YAG laser irradiation in root canals using pulse durations of 180 and 320 μs. Thirty extracted human teeth were used in this study. The teeth were enlarged up to ISO 40 (multi-rooted) or up to ISO 60 (single-rooted) by conventional technique using K-files. Then the teeth were placed into a water bath with a constant temperature of 37 °C and then irradiated with an Nd:YAG laser having an output power of 1.5 W, a frequency of 15 Hz, using an optic fiber of 200 μm diameter. The temperature on the root surface was measured by means of attaching thermocouples in three areas (coronal, mesial, and apical regions) of the root canals. The thermographic study showed that the average temperature elevation for both pulse durations on the root surfaces was less than 9 °C. There was no significant difference in the observed temperatures in coronal and mesial areas. Though a higher increase of temperature was observed in the apical region when the pulse length of the Nd:YAG laser was 320 μs. The results of the study showed that the temperature rises during Nd:YAG laser irradiation with parameters used in this study minimal to cause damage on bone and periodontal tissues. Moreover, it was suggested that in order to have lower temperature in the apical region, an Nd:YAG laser with a pulse length of 180 μs is preferred than one with a pulse length of 320 μs.

Dynamical behaviour of the Pirani sensor

The conventional Pirani gauge has poor performance at atmospheric pressures since here the stationary thermal conductivity of gases saturates. In contrast, the heat capacity of the gas does not saturate. It is accessible by a pulsed operation of the wire. The present paper gives an investigation of the Pirani gauge signal for the non-stationary heating and cooling processes. As follows from the experimental data and theoretical estimates, at atmospheric pressure a substantial amount of energy is stored in the gas, much more than in the wire. However, the energy of the gas has only a rather small effect on heating and cooling rates. The reasons for this behaviour are the strong heat losses due to the thermal conductivity of the gas, the rather weak thermal coupling between the wire and surrounding gas as well as the smallness of the average temperature elevation of the gas over ambient. Nevertheless, the effect of the heat capacity of the gas on the rates is sufficiently strong to provide a usable measuring signal. The pulsed operation of the wire and the recording of the time-dependent signal can be accomplished by a smart controller. Such an instrument would provide a substantially improved performance of the Pirani sensor at pressures above 100 mbar.

Effect of ultrasound on the neonatal rat brain

Six-day-old rat neonates were exposed to 2.25 MHz continuous wave (CW) ultrasound for 5 min at an intensity of 2.5 W/cm 2 (SATA). The temperatures on the head surface and in the mouth were measured. There was a higher average temperature elevation in the mouth (9°C) than on the head surface (7°C). Survival differs between control and exposed groups at 30 days after exposure. Ninety percent of the control group lived to 30 days, versus 59.7% for the exposed group. At differing times following exposure, the brains of the pups were removed and tested for enzymatic activities. Changes in acetylcholine esterase and in 2′,3′-cyclic nucleotide phosphohydrolase activities were not statistically significantly different from controls. There were no significant differences in brain weight and total protein between control and exposed pups.

Thermally Excited Resonating Membrane Mass Flow Sensor

A mass flow sensor based on the frequency shift of a resonating microstructure is being developed, using a measurement principle of the thermoanemometry type. The sensor is to be applied for mass flows up to 10 standard cubic centimeters per minute (sccm; 10sccm = 0.17 mg s -1), with a high sensitivity, a high resolution and a fast response. Here we report on the first prototype consisting of a 2 μm thick membrane: the temperature elevation of the thermally excited vibrating membrane affects its resonance frequency. The three-dimemsional heat transfer within the membrane and the mass flow is modeled, and expressions are derived for the resonance frequencies of initially curved and stressed membranes. Experiments have been carried out for nitrogen flows of up to 500 sccm passing over thermally excited membranes. Predicted and measured values for the shift of the resonance frequency agree well. The sensitivity of the average temperature elevation to the mass flow is quite small: at 10 sccm the cooling effect of the mass flow is only 0.2% of the heat loss by conduction to the substrate. At a resonance frequency of 5.0 kHz, and an average temperature elevation of the mebrane of 8°C, this still leads to a frequency change of 13 Hz in the mass flow range from zero to 10 sccm. Suggestions are presented for increasing the sensitivity of the sensor.

Effect of Endotoxemia on Contrast Media Reactions

Since complement activation is sharply temperature-dependent, we have examined the effects of fever produced by a very small dose of endotoxin on contrast media lethality in rabbits. After the injection of 8.2 ml/kg of 52% methylglucamine iodipamide, a group of rabbits exhibiting an average temperature elevation of 1.5 degrees C had a 100% mortality rate. This was contrasted to a 30% mortality in control rabbits receiving contrast alone, and no mortality in rabbits receiving endotoxin alone. The rabbits with fever and increased mortality exhibited increased activation of serum complement. From this preliminary data it appears that caution should be observed in performing a contrast examination in a patient with endotoxemia and/or a fever.

Intensive care delirium. The effect of outside deprivation in a windowless unit.

The incidence of postoperative delirium in 50 consecutive surgical patients treated for at least 72 hours in an intensive care unit without windows was compared to 50 similar patients in an intensive care unit possessing windows. Over twice as many episodes of organic delirium were seen in the intensive care unit without windows, and among those patients with abnormal hemoglobin or blood urea nitrogen levels, the incidence of delirium was almost three times greater in the windowless unit. Age, type of surgical procedure, average temperature elevation following surgery, surgical staff, nursing care, or socioeconomic class of the patients had no effect on the incidence of delirium. It is concluded that the presence of windows is highly desirable in the intensive care unit for the prevention of sensory deprivation.