Decrease In Ambient Temperature Research Articles

Highly Sensitive Temperature Sensing Probe Based on Deviation S-Shaped Microfiber

A deviation S-shaped microfiber was proposed and packaged in a capillary by glycerin solution. The high-temperature sensitivity performance was experimentally demonstrated. With the decrease in ambient temperature from 73.05 °C to 23.46 °C, the resonant dip on the transmission spectra red-shifts continually due to the co-operation between the refractive index increase of glycerol and the thermal expansion of packaging materials. The high sensitivity of ∼11 nm/°C promises high-sensitive monitoring of the slight temperature fluctuation in some specific biological and chemical reaction process.

Parametric investigation of a modified gas turbine power plant

In this paper, a parametric study of a gas turbine power plant with the implementation of intercooling, reheating and regeneration is proposed. Thermal efficiency and the specific fuel consumption are evaluated with respect to various parameters including intercooler effectiveness, regenerator effectiveness, ambient temperature, compression ratio, reheating temperature, turbine isentropic efficiency, and compressor isentropic efficiency. The analytical formulas to evaluate the thermal efficiency are derived taking into consideration the operation conditions. MATLAB software is used to build the model. Modeled results show that the thermal efficiency increases with the increase of intercooler and regenerator effectiveness, increase of reheating temperature, decrease of ambient temperature, increase of turbine and compressor efficiencies. Thermal efficiency rises with compression ratio up to 2.2, and then it starts to decrease with increasing of compression ratio. Specific fuel consumption decreases with the decrease of ambient temperature, intercooler and regenerator effectiveness. SFC decrease with compression ratio up to 2.2. Then, it rises with the rise of compression ratio. Comparison between simple gas turbine and current model is presented also, and results indicated that at any ambient temperature, the thermal efficiency of the proposed model is higher than the simple cycle within 16–20%.

Ambient temperature and cardiovascular mortality: a systematic review and meta-analysis.

IntroductionOur study aims at identifying and quantifying the relationship between the cold and heat exposure and the risk of cardiovascular mortality through a systematic review and meta-analysis.Material and MethodsA systematic review and meta-analysis were conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Peer-reviewed studies about the temperature and cardiovascular mortality were retrieved in the MEDLINE, Web of Science, and Scopus databases from January 2000 up to the end of 2015. The pooled effect sizes of short-term effect were calculated for the heat exposure and cold exposure separately. Also, we assessed the dose–response relationship of temperature-cardiovascular mortality by a change in units of latitudes, longitude, lag days and annual mean temperature by meta-regression.ResultAfter screening the titles, abstracts and full texts, a total of 26 articles were included in the meta-analysis. The risk of cardiovascular mortality increased by 5% (RR, 1.055; 95% CI [1.050–1.060]) for the cold exposure and 1.3% (RR, 1.013; 95% CI [1.011–1.015]) for the heat exposure. The short-term effects of cold and heat exposure on the risk of cardiovascular mortality in males were 3.8% (RR, 1.038; 95% CI [1.034–1.043]) and 1.1%( RR, 1.011; 95% CI [1.009–1.013]) respectively. Moreover, the effects of cold and heat exposure on risk of cardiovascular mortality in females were 4.1% (RR, 1.041; 95% CI [1.037–1.045]) and 1.4% (RR, 1.014; 95% CI [1.011–1.017]) respectively. In the elderly, it was at an 8.1% increase and a 6% increase in the heat and cold exposure, respectively. The greatest risk of cardiovascular mortality in cold temperature was in the 14 lag days (RR, 1.09; 95% CI [1.07–1.010]) and in hot temperatures in the seven lag days (RR, 1.14; 95% CI [1.09–1.17]). The significant dose–response relationship of latitude and longitude in cold exposure with cardiovascular mortality was found. The results showed that the risk of cardiovascular mortality increased with each degree increased significantly in latitude and longitude in cold exposure (0.2%, 95% CI [0.006–0.035]) and (0.07%, 95% CI [0.0003–0.014]) respectively. The risk of cardiovascular mortality increased with each degree increase in latitude in heat exposure (0.07%, 95% CI [0.0008–0.124]).ConclusionOur findings indicate that the increase and decrease in ambient temperature had a relationship with the cardiovascular mortality. To prevent the temperature- related mortality, persons with cardiovascular disease and the elderly should be targeted. The review has been registered with PROSPERO (registration number CRD42016037673).

Fatigue crack growth and damage characteristics of high-speed rail at low ambient temperature

Abstract Low temperature can be a significant problem affecting safety and maintenance of railway. In this study, the fatigue crack growth rate and rolling contact fatigue damage behaviors of high-speed rail material under different temperature conditions were investigated by a series of experiments. The results indicate that the stress and strength of rail material increase with the decrease of ambient temperature. The crack growth rate at 0 °C and − 20 °C is similar with that at 20 °C. While, when the temperature decreases to − 60 °C, the growth rate of crack increases sharply. The promotion of rail embrittlement at low temperature accompanied with the action of high stress causes the rapid failure and increase of surface crack length and subsurface crack damage. Meanwhile, three crack growth mechanism models at different temperatures can be inferred. The brittle fracture mode is increasingly apparent with the temperature decreasing.

Effect of temperature and charge stand on electrochemical performance of fiber Nickel–Cadmium cell

The effect of temperature and charge stand periods on the discharge capacity of Nickel–Cadmium (Ni–Cd) cell is investigated quantitatively. 15 A h Ni–Cd cells with NiOOH cathode and Cd anode were used as test system. The cells were charged in two step constant current modes up to 1.7 V, then stored at different temperatures from–20 to 60°C for charge stand periods of 1 day, 7 days and 15 days and discharged at 1 С rate current until the cell voltage reached 1.0 V. Although the discharge capacity of these cells at and around room temperature i.e., 10 to 30°C is good, at temperatures below 0°C and above 40°C, the performance is poor. Also from 40 to 60°C, the discharge capacities decreased with charge stand periods due to self discharge and for sub ambient temperature decrease in capacity is minimal.

Inclusion of absorption heat pumps into heat power plant scheme for stage heating efficiency increase of delivery water

Design analysis of absorption heat pumps use for delivery water stage heating levelling-off at ambient air temperature decrease has been reported in the present paper.

Computational Investigation on Soot Mechanism of Diesel and Diesel/n-Butanol Blend in Constant Volume Chamber with Various Ambient Temperatures

Computational investigation was carried out in an optical constant volume chamber to explore the combined effects of initial ambient temperatures (800, 900, and 1000 K) and n-butanol additive (20% volume fraction of n-butanol) on diesel combustion and soot characteristics. An improved phenomenological soot model integrated with a reduced n-heptane/n-butanol/polycyclic aromatic hydrocarbon (PAH) mechanism was developed and implemented into the KIVA-3V R2 code to study the soot formation and oxidation mechanism. The predicted chamber pressure and heat release rate as well as soot mass trace and distribution showed good agreements with the experimental data. Results indicated that the ignition delay was retarded and total soot mass was reduced with the decrease of initial ambient temperature and with the n-butanol additive. The heat release rate of pure diesel demonstrated a transition from diffusion-dominated combustion at 1000 K to premix-dominated combustion at 800 K. Diesel/n-butanol blend showed no obvi...

Calibration of Contactless Pulse Oximetry

Contactless, camera-based photoplethysmography (PPG) interrogates shallower skin layers than conventional contact probes, either transmissive or reflective. This raises questions on the calibratability of camera-based pulse oximetry. We made video recordings of the foreheads of 41 healthy adults at 660 and 840 nm, and remote PPG signals were extracted. Subjects were in normoxic, hypoxic, and low temperature conditions. Ratio-of-ratios were compared to reference SpO2 from 4 contact probes. A calibration curve based on artifact-free data was determined for a population of 26 individuals. For an SpO2 range of approximately 83% to 100% and discarding short-term errors, a root mean square error of 1.15% was found with an upper 99% one-sided confidence limit of 1.65%. Under normoxic conditions, a decrease in ambient temperature from 23 to 7°C resulted in a calibration error of 0.1% (±1.3%, 99% confidence interval) based on measurements for 3 subjects. PPG signal strengths varied strongly among individuals from about 0.9 × 10 to 4.6 × 10 for the infrared wavelength. For healthy adults, the results present strong evidence that camera-based contactless pulse oximetry is fundamentally feasible because long-term (eg, 10 minutes) error stemming from variation among individuals expressed as A*rms is significantly lower (<1.65%) than that required by the International Organization for Standardization standard (<4%) with the notion that short-term errors should be added. A first illustration of such errors has been provided with A**rms = 2.54% for 40 individuals, including 6 with dark skin. Low signal strength and subject motion present critical challenges that will have to be addressed to make camera-based pulse oximetry practically feasible.

Passive and active cooling for the outdoor built environment – Analysis and assessment of the cooling potential of mitigation technologies using performance data from 220 large scale projects

Local and global climate change increases the ambient temperature of cities by several degrees with important consequences on energy consumption, health and the economy. Advanced urban mitigation technologies contribute to decrease the ambient temperature and counterbalance the impact of urban heat islands. The present paper analyses and presents in a comparative way the mitigation potential of the known mitigation technologies using performance data from about 220 real scale urban rehabilitation projects. The average and peak temperature drop of reflective technologies, greenery, evaporative systems, earth to air heat exchangers and their combinations is calculated and presented. The mitigation potential of the main systems like cool roofs, cool pavements, green roofs, urban trees, pools and ponds, sprinklers, fountains, and evaporative towers, is analysed. It is found that the potential of the main mitigation technologies is considerable and can counterbalance UHI effects partly or fully. The average peak temperature drop calculated for all projects is close to 2K, while the corresponding decrease of the average ambient temperature is close to 0.74K. Almost 31% of the analysed projects resulted in a peak temperature drop below 1K, 62% below 2K, 82% below 3K and 90% below 4K.

Structural and magnetic investigations of Cr substituted NiFe2O4 nanostructures

Ultrafine nanocrystalline Chromium (Cr) substituted Nickel Ferrites with general formula of NiCrxFe2-xO4 (0 ≤ x ≤ 1) have been made with co-precipitation method. Structure and phase of synthesized nanoparticles were identified by X-ray diffraction (XRD). The results assure for formation of single phase cubic spinel structure with Fd3m symmetry. Increasing trend in X-ray densities due to decrease in lattice parameter has been observed with increasing Cr concentration in NiFe2O4. Morphology of synthesized nanoparticles were analysed with field emission scanning electron microscope (FE-SEM) and it has been observed that nanoparticles were dense and evenly distributed over the whole surface. Room temperature and low temperature magnetic measurements were investigated with physical property measurement system (PPMS). It has been found that magnetic coercivity was boosted with Cr substitution at level x = 1 with decreasing trend in saturation magnetization at room temperature. However, low temperature magnetic analyses for x = 1 showed increase in saturation magnetization and coercivity with decrease in ambient temperature.

Ignition characteristics of kerosene droplets with the addition of aluminum nanoparticles at elevated temperature and pressure

The effects of various ambient pressure and temperature conditions on the ignition characteristics of kerosene-based nanofluid droplets were investigated experimentally. Individual kerosene droplet containing 0.1 or 1% by mass was mounted on the tip of silicon carbide (SiC) fiber and exposed to ambient temperatures in the range of 400–700°C and ambient pressures in the range of 0.1–2.5MPa under normal gravity. An increase in ambient pressure was observed to reduce the ignition location distance below a droplet. The ignition delay times of pure kerosene droplets were also examined for comparison. The results showed that the ignition delay time of Al NPs-laden kerosene droplets decreased exponentially with increasing temperature, as did that of pure kerosene droplets. An ambient pressure increase from 0.1 to 2.5MPa led to a decrease in the lowest ambient temperature for ignition from 800 to 400°C. At pressures greater than 1MPa, the ignition delay times of droplets with 1% Al were shorter than those of pure kerosene and kerosene with 0.1% Al. Furthermore, as the ambient pressure increased from 0.1 to 2.5MPa, the ignition delay was found to decrease and then increase exceeding the limiting pressure.

Seasonal changes in supercooling capacity and major cryoprotectants of overwinteringAsian longhorned beetle (Anoplophora glabripennis) larvae

AbstractTheAsian longhorned beetle is a destructive trunk borer in forests and urban landscape trees.Dynamic changes in the supercooling capacity ofAnoplophora glabripennislarvae in a natural population and the mechanism of cold hardiness during different overwintering periods at physiological and biochemical levels were explored.The results showed that the supercooling point of overwintering larvae decreased initially before increasing subsequently with seasonal changes in ambient temperature. Fresh mass and glycogen tended to decrease initially and then reached their minimum levels inJanuary. Total amounts of low molecular weight substances and free amino acids in the haemolymph increased gradually as the ambient temperature decreased. Glycerol (779.80 ± 29.10 µm/mL) and trehalose (104.35 ± 12.38 µm/mL) concentrations were always higher than those of glucose and mannitol. All low molecular weight substances (besides trehalose) were almost metabolized by early spring. The concentrations of serine, phenylalanine, valine, leucine, proline, glutamic acid and alanine all reached their highest level in the colder winter months.The results of the present study suggest thatA. glabripennislarvae accumulate cryoprotectants to improve their supercooling capacity, and enhance cold hardiness by reducing the supercooling point with respect to a decrease in ambient temperature until freezing temperatures appear.Anoplophora glabripennislarvae are a freeze‐tolerant insect.

Performance maximization of IGCC plant considering operating limitations of a gas turbine and ambient temperature

We predicted the available maximum power output of Integrated gasification combined cycle (IGCC) plants under the operating limitations of a gas turbine. The power block of the IGCC using an F-class gas turbine was modeled, and its interactions of mass and energy with other components such as a gasifier and an air separation unit were considered. Variation in the gas turbine power output with nitrogen dilution was simulated, and the operating conditions under which the power should be limited below an allowable maximum were determined. The maximum net power output of the IGCC plant under the restrictions of syngas turbine power (232 MW) and blade temperature were estimated in a wide range in terms of ambient temperature and integration degree, and the optimal integration degree for each ambient temperature is suggested. At relatively high temperatures over 19°C, zero integration degree (air for the air separation unit is supplied solely from the ambient) provides the highest net power output and efficiency. As ambient temperature decreases, a higher integration degree provides higher net power. The optimal net IGCC power output varies from 260 MW to 347 MW (33%) in the ambient temperature range of 40°C to -10°C, while the optimal net efficiency varies by about one percentage point.

Seasonal Cold Exposure Modulates Metabolic Phenotype and Mitochondrial Function in Obese Golden‐Mantled Ground Squirrels

Golden‐mantled ground squirrels (Callospermophilus lateralis; GMGS) develop seasonal obesity in early autumn, which provides essential fuel stores for successful hibernation through the long Rocky Mountain winter. This is facilitated by circannual variations in hormones regulating food intake and metabolism independent of environmental cues, but is accompanied by a decrease in ambient temperature that might also influence metabolic phenotype. The present study evaluated the effect of seasonal cold exposure on body composition, glucose tolerance and tissue mitochondrial function in obese GMGS prior to hibernation. We hypothesized that cold exposure compliments seasonal adiposity by altering metabolic and mitochondrial parameters that further optimize physiological preparation for hibernation. Adult GMGS were captured in mid‐summer and transferred to an animal facility maintained at 22 deg C, and provided standard rodent chow (Harlan 2918) and water ad libitum. Animals were allowed to acclimate to the new environment for at least 4 weeks before being sacrificed for baseline evaluation as lean summer controls (Lean; N = 7) or randomized to continue on the ab libitum diet for 4–6 more weeks at 22 deg C (Ob‐warm; N = 4) or 15 deg C to simulate the seasonal decrease in temperature normally encountered by animals in the wild (Ob‐cold; N = 6). Lean animals had lower body weight (247 ± 12 g) and body fat (25 ± 4 %) compared to obese groups, with no difference between Ob‐warm (312 ± 16 g; 47 ± 2 % fat) and Ob‐cold (302 ± 23 g; 47 ± 5 % fat). Blood glucose disposal following a 2 g/kg i.p. glucose challenge was much more rapid in Lean compared to Ob groups, and greater in Ob‐cold vs. Ob‐warm animals, indicating an expected decrease in glucose tolerance with obesity that was attenuated by cold exposure. Liver mitochondria from obese animals exhibited greater maximal ADP‐dependent (OXPHOS) respiration vs. Lean with both carbohydrate (pyruvate) and lipid (palmitoylcarnitine) substrates. Cold exposure attenuated the increase in lipid OXPHOS in obese animals, but had no effects on carbohydrate OXPHOS capacity. Conversely, in cardiac mitochondria, maximal and carbohydrate OXPHOS capacity was similar between Lean and Ob‐warm groups, but significantly elevated in Ob‐cold animals. In muscle mitochondria, obesity reduced carbohydrate OXPHOS capacity, with no significant effects on lipid OXPHOS and no modulation by cold exposure. Taken together, these data suggest that seasonal cold exposure modifies metabolic responses to obesity in pre‐hibernating GMGSs, leading to improvements in systemic glucose disposal, tissue‐specific alterations in mitochondrial substrate utilization, and enhancement of cardiac mitochondrial OXPHOS capacity. These adaptations might serve to optimize systemic preparation for prolonged hypometabolism and reliance on lipid stores during hibernation, and provide insight into the metabolic effects of physiologic cold exposure with potential relevance to obesity‐related metabolic disorders.Support or Funding InformationFunding for this work was provided in part by grants from the USDA and American Heart Association to AJC.

Features of crystal and magnetic structures of solid solutions BaFe12-xDxO19 (D=Al3+, In3+; x=0.1) in a wide temperature range

The study of barium ferrites partially substituted by diamagnetic Al and In ions has been performed by the neutron diffraction method with high resolution. Both samples BaFe11.9D0.1O19 (\( D=Al\) and In) preserve a magnetoplumbit structure in a broad temperature range from 4.2K to 730K. The Invar effect was found in the low-temperature region in both samples. This unusual behavior of the unit cell was explained by changes of the regime of mutual rotations and tilts of the oxygen octahedra. The magnetic structure described by the Gorter model is saved up to the ferrimagnetic and paramagnetic phase transition temperature, 705K and 695K, for the Al- and In-substituted ions, respectively. The substitution of iron by aluminum or indium ions decreases the total magnetic moment of the investigated composition from \( 20 \mu_{B}\) (BaFe12O19) to 19 and \( 16.7 \mu_{B}\), respectively. A higher coercitivity was found \( H_{c}\sim 0.1\) T, for the In-substituted compositions, differently from \( H_{c}\sim 0.007\) T of the Al-doped ones because of the frustration of the magnetic structure. The decrease of ambient temperature increases microstresses in crystallites because of the increasing influence of the magnetic subsystem.

Performance investigations of an R404A air-source heat pump with an internal heat exchanger for residential heating in northern China

Air-source heat pumps (ASHP) have been widely used for residential heating due to its energy-saving and high efficiency characteristics. However, the performance of an ASHP reduces as the ambient temperature decreases. In order to investigate the effect of ambient temperature on ASHP performance, an ASHP with an internal heat exchanger (IHX) using R404A as refrigerant was developed and studied at low ambient temperatures. The theoretical simulation was first performed to evaluate the performance of the ASHP with IHX and compared with three different cycles. The simulation results were validated by data available from literature and experimental data in this study. The results showed that the R404A ASHP system with IHX had a good potential for residential heating. Further investigation was performed to compare the performance of the R404A ASHP with and without IHX. The comparison results showed that the performance of the ASHP with IHX was far better than that of the ASHP without IHX. As the ambient temperature decreased from 0 °C and −26 °C, the improvement of the heating capacity of the R404A ASHP with IHX increased from 5.91% to 15.92% while the COP improvement increased from 10% to 20%. This indicated that the IHX technology became more and more effective as the ambient temperature dropped lower and lower.

Influence of daily ambient temperature on mortality and years of life lost in Chongqing

To evaluate the influence of extreme ambient temperature on mortality and years of life lost (YLL) in Chongqing. The daily mortality, meteorology and air pollution index data in Chongqing from the 1(st) January 2010 to the 31(st) December 2013 were collected. Distributed lag non-linear model (DLNM) was used to assess the influence of daily ambient temperature on daily number of deaths and daily YLL respectively. The delayed and cumulative effects of extreme temperature on sex, age, and cause-specific mortality were also assessed. The relationships between ambient temperature and non-accidental, cardiovascular disease and respiratory disease mortalities and YLL were U-shaped or W-shaped. The effect of heat was obvious on that day, peaked on day 7, and lasted for two weeks, whereas the effect of cold was obvious a week later and lasted for a month. As 1 ℃ increase of ambient temperature, the cumulative relative risks (CRR) of high temperature across lag 0-7 days on non-accidental, respiratory disease and cardiovascular disease mortalities were 1.05 (95%CI: 1.03-1.07), 1.08 (95%CI: 1.05-1.11) and 1.05 (95%CI: 1.01-1.09) respectively. The effects of heat on YLL for each cause were 23.81 (95%CI: 12.31-35.31), 14.34 (95%CI: 8.98-19.70) and 4.43 (95%CI: 1.64-7.21), respectively. On cold days, 1 ℃ decrease of ambient temperature was correlated with an increase in CRR of 1.06 (95%CI: 1.04-1.08), 1.09 (95%CI:1.06-1.12) and 1.06 (95%CI: 1.02-1.11) from lag 0 to 14 for non-accidental, respiratory disease and cardiovascular disease mortalities, respectively. The estimated YLL were 23.34 (95%CI: 10.04-36.64), 16.39 (95%CI: 10.19-22.59) and 2.61 (95%CI: -0.61-5.82). People aged ≥65 years tend to have higher CRR and YLL than those aged <65 years. On high temperature days, the CRR in women was higher than that in men, while the YLL in women was lower than that in men. On low temperature days, both the CRR and YLL in women were higher than those in men. Both high and low ambient temperature have adverse health effects. People aged ≥65 years are more sensitive to both high and low ambient temperature. Younger men are more sensitive to high ambient temperature and women and elder men are sensitive to low ambient temperature. It is necessary to take targeted measures to protect the population in Chongqing from the adverse influence of extreme ambient temperature.

Does local ambient temperature impact children's blood pressure? A Chinese National Survey.

BackgroundSeveral studies demonstrated a short-term association between ambient temperature and blood pressure. However, few studies have assessed the long-term effect of ambient temperature on children’s blood pressure. The present study aimed to investigate the association between long-term exposure to local ambient temperature and children’s blood pressure in China.MethodsWe analyzed the systolic (SBP) and diastolic blood pressure (DBP) data of 71,763 children from 2010 Chinese National Survey on Students’ Construction and Health (CHNSCH), and local annual average ambient temperature, relative humidity, air pollutants data from China Meteorological Administration and Ministry of Environment Protection of China. We used generalized additive model (GAM) with non-linear function to examine the effects of ambient temperature on children’s blood pressure.ResultsThe results showed that decrease of ambient temperature was negatively associated with increase of both SBP and DBP in Chinese children while adjusting for individual characteristics, socioeconomic conditions, air pollutants and relative humidity. The largest alteration of SBP related to the temperature difference was observed from 20.4 to 9.6 °C, with 9.0 mmHg (95 % CI: 8.4, 9.5) increase in SBP, while the largest alteration of DBP was observed from 21.7 to 10.2 °C, with 6.1 mmHg (95 % CI: 5.6, 6.6) increase in DBP. However, when temperature below 9.6 and 10.2 °C, SBP and DBP started to decrease, which might be caused by the use of heating system in the extreme cold areas.ConclusionsPublic health policy should be improved for protecting children’s cardiovascular health from adverse effects of low temperature. Development of heating system in moderate cold area might be a good solution.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-016-0119-y) contains supplementary material, which is available to authorized users.

Analysis of seasonal expression levels of wheat fructan exohydrolase (FEH) genes regulating fructan metabolism involved in wintering ability

In northern regions, winter wheat (Triticum aestivum L.) accumulates fructan during cold-acclimation in autumn and freeze-acclimation in early winter. The content of fructan in wheat crown tissues is associated with both freezing tolerance and snow mold resistance, and expression levels of fructan synthesis genes in leaf and crown tissue are correlated with both changes and varietal differences in fructan accumulation levels of wheat during cold- and freeze-acclimation. Fructan hydrolysis activity has also been thought be involved in wintering ability of wheat. Since several kinds of gene homologs encoding fructan exohydrolase (FEH: EC. 3.2.1.153, 154) with different substrate specificities have recently been cloned from wheat, changes in transcript levels of wheat FEH genes in field-grown wheat cultivars from autumn to spring were analyzed to investigate regulation of seasonal changes in fructan content. The seasonal expression patterns of five genes encoding 1-FEH, 6-FEH (and Wfh-sm3), 6&1-FEH and 6-KEH (kestose exohydrolase) varied. Among the five genes, only seasonal changes in the expression of wfh-sm3, which codes an enzyme that is able to hydrolyze almost all components of fructan that has accumulated in hardened wheat tissues, were correlated with those changes in fructan contents. Moreover, the transcript levels of wfh-sm3 were low in snow mold-resistant cultivars that accumulate high levels of fructan. The transcript levels of 6-FEH increased with decrease in ambient temperatures and the levels decreased under snow. The analysis indicated that cooperative expression of 6-FEH and 1-FEH genes might be related to the seasonal changes and varietal difference in mono- and disaccharide contents. This study showed that the coordinated expression of FEH genes in wheat was related to the regulation of water-soluble carbohydrate accumulation from autumn to early winter and fructan consumption under snow cover as well as energy supply and that wheat FEHs also play an important role in the varietal difference in freezing tolerance and snow mold resistance. In particular, the expression of wfh-sm3 may regulate fructan metabolism associated with tolerance for wintering stresses.

Exergoenvironmental analysis for a geothermal district heating system: An application

Energy sources are of great importance in relation to pollution of the world. The use of renewable energy resources and the creation of more efficient energy systems make great contributions to the prevention of greenhouse gases. Recently, many studies indicate that the energy conversion systems have many advantages in terms of technical and economic point of view. In near future, environmental impact is going to play an important role in the selection/design of such energy resources and systems. In this study, the Afyon GDHS (geothermal district heating system) having actual operating conditions is investigated at the component level in terms of environmental impact by using exergoenvironmental analysis. Moreover, the effects of ambient and wellhead temperatures on the environmental impacts of the system are discussed. The results show that a great part of total environmental impact of the system occurs from the exergy destructions of the components. Therefore, the environmental impacts can be reduced by improving their exergetic efficiencies instead of design changes of the system components. The environmental impacts of the system are reduced when the ambient temperature decreases and the wellhead temperature increases. Thus, it might not be necessary to conduct separately the exergoenvironmental analysis for different ambient temperatures.