Natural Ambient Temperature Research Articles

Facile Preparation of a Low-Cost Liquid Interlayer Material with Intelligent UV-NIR-Shielding Function for Smart Windows.

High-performance interlayer materials have garnered considerable interest owing to their low manufacturing costs and applicability in smart windows. In this study, a novel smart-window interlayer material capable of selective shielding against both near-infrared (NIR) and ultraviolet (UV) radiation is developed based on the light transmittance control mechanism. An excellent thermoresponsive liquid, denoted as CDs@TRL (viz., carbon quantum dots at thermal-responsive liquid), is synthesized by compositing biomass-based fluorescent carbon quantum dots (CDs) and poly(N-isopropylacrylamide) (pNIPAM) at natural ambient temperature and in an aqueous phase. Due to the characteristics of CDs and synergistic effect of hydrogen bonds, CDs@TRL exhibits a high specific heat capacity (4.41 kJ kg-1 K-1), large thermal storage capacity (264.6 kJ kg-1), and better UV-NIR-blocking properties, compared to pure pNIPAM, as well as improves the sensitivity of thermal response. When injected into a window as a liquid interlayer, CDs@TRL can intelligently adjust the light transmittance according to ambient light intensity to achieve an intelligent response. The shielding rate of a 10 mm-thick CDs@TRL composite liquid against UV radiation (200-400 nm) was more than 95% in an overcast environment with insufficient light and close to 100% in a well-lighted environment. In addition, CDs@TRL is a cost-effective material that can be prepared from a wide range of raw material sources using a simple preparation process and exhibits excellent mobility and recyclability. Because of these features, it is considered to be a promising candidate for developing energy-saving and climate-adapted smart windows.

Shape memory polymer with programmable recovery onset.

Stimulus-responsive shape-shifting polymers1-3 have shown unique promise in emerging applications, including soft robotics4-7, medical devices8, aerospace structures9 and flexible electronics10. Their externally triggered shape-shifting behaviour offers on-demand controllability essential for many device applications. Ironically, accessing external triggers (for example, heating or light) under realistic scenarios has become the greatest bottleneck in demanding applications such as implantable medical devices8. Certain shape-shifting polymers rely on naturally present stimuli (for example,human body temperature for implantable devices)8 as triggers. Although they forgo the need for external stimulation, the ability to control recovery onset is also lost. Naturally triggered, yet actively controllable, shape-shifting behaviour is highly desirable but these two attributes are conflicting. Here we achieved this goal with a four-dimensional printable shape memory hydrogel that operates via phase separation, with its shape-shifting kinetics dominated by internal mass diffusion rather than by heat transport used for common shape memory polymers8-11. This hydrogel can undergo shape transformation at natural ambient temperature, critically with a recovery onset delay. This delay is programmable by altering the degree of phase separation during device programming, which offers a unique mechanism for shape-shifting control. Our naturally triggered shape memory polymer with a tunable recovery onset markedly lowers the barrier for device implementation.

Naked neck gene and intermittent thermal manipulations during embryogenesis improve posthatch performance and thermotolerance in slow-growing chickens under tropical climates

Many studies have shown that thermal manipulations during the incubation (TMI) and naked neck gene (Na) positively affect heat-stressed broilers' thermotolerance, hatching process, and posthatch performance. Their combination could increase the beneficial effect on broilers reared under natural tropical climatic conditions. The aim of this study was to investigate the effects of the Na gene and TMI on hatching and posthatch performance of slow-growing broilers under tropical climates. The study included 1,200 hatching eggs from 2 different crosses: 1) females and males, both with a normal or fully feathered neck (na na group), and 2) females (with a normal neck) and males (bare neck) (Na na group), incubated in similar conditions until d 7. Thereafter, they were assigned to 3 subgroups for each cross: the control group (C) was incubated at standard incubation conditions (37.8°C, 60% RH). The TMI-1 group was subjected to TMI-1 (T=38.5°C, RH=65%, E10-18, 6 h/d) and TMI-2 group to TMI-2 (T=39.5°C, RH=65%, E7-16, 12 h/d). Between 450 and 504 h of incubation, eggs were checked for hatching events. During the posthatch phase, chicks from each incubation subgroups (Na na-C, Na na-TMI-1, Na na-TMI-2, na na-C, na na-TMI-1, na na-TMI-2) were raised for 12 wk at a tropical natural ambient temperature. Hatchability, hatching time, chick's temperature, final body weight (FBW), and feed conversion ratio (FCR) were determined. The results revealed that the Na gene reduced (P ˂ 0.05) hatchability. The control group had the highest mortality rate compared to TMI-1 and TMI-2 groups. There was an interaction between genotype and TMI on incubation duration, hatching weight, chick quality, FBW, and FCR (P ˂ 0.05). In conclusion, the Na gene influenced the effects of thermal manipulation. TMI-1 combined with Na gene improved the productive performances of broilers in a tropical climate.

Stress Response of European Common Frog (Rana temporaria) Tadpoles to Bti Exposure in an Outdoor Pond Mesocosm

The biocide Bacillus thuringiensis var. israelensis (Bti) is applied to wetlands to control nuisance by mosquitoes. Amphibians inhabiting these wetlands can be exposed to Bti multiple times, potentially inducing oxidative stress in developing tadpoles. For biochemical stress responses, ambient water temperature plays a key role. Therefore, we exposed tadpoles of the European common frog (Rana temporaria) three times to field-relevant doses of Bti in outdoor floodplain pond mesocosms (FPM) under natural environmental conditions. We sampled tadpoles after each Bti application over the course of a 51-day experiment (April to June 2021) and investigated the activity of the glutathione-S-transferase (GST) and protein carbonyl content as a measure for detoxification activity and oxidative damage. GST activity increased over the course of the experiment likely due to a general increase of water temperature. We did not observe an effect of Bti on either of the investigated biomarkers under natural ambient temperatures. However, Bti-induced effects may be concealed by the generally low water temperatures in our FPMs, particularly at the first application in April, when we expected the highest effect on the most sensitive early stage tadpoles. In light of the global climate change, temperature-related effects of pesticides and biocides on tadpoles should be carefully monitored - in particular since they are known as one of the factors driving the worldwide decline of amphibian populations.

Growth, development and nutritional indices of tobacco caterpillar, Spodoptera litura (F) raised on bell pepper plants grown under elevated CO2 and temperature conditions


 The experiment was conducted at experimental farm situated at 30◦5’N latitude and about 77◦11’E longitudes, an elevation of 1260 m above mean sea level of Department of Environmental Science, Dr YS Parmar University of Horticulture and Forestry Nauni, Solan, Himachal Pradesh during 2014 and 2015, to study the effect of elevated CO2 (eCO2) and elevated temperature (eT) on growth, development and nutritional indices of Spodopteralitura on bell pepper plant. Feeding trials with foliage feeding insect S. litura was conducted using foliage of bell pepper plants grown under four concentrations of CO2 and temperature, viz. three Open Top Chambers, (T1: OTC eCO2 550±10 ppm; T2: OTC with elevated temperature 1°C higher and eCO2 550±10 ppm; T3: OTC with ambient temperature and CO2 and T4: natural ambient air and temperature in open. Biochemical analysis of foliage revealed that plants grown under elevated CO2 had lower nitrogen. The larvae fed on eCO2 as well as eCO2 and temperature foliage exhibited greater consumption compared to the larvae fed on foliage under ambient CO2. Larval duration also increased by two days. The eCO2 and eCO2 and temperature foliage was more digestible with higher values of approximate digestibility. The relative consumption rate increased whereas the efficiency parameters, viz. efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD), and relative growth rate (RGR) decreased in eCO2 and eCO2 and temperature. The consumption and weight gain of the larvae were negatively and significantly influenced by leaf nitrogen.

Оценка склонности к самовозгоранию и газовыделения углесодержащих пород отвалов и шламов угольных предприятий

Rock dumps of coal mining and coal processing enterprises contain coal, which is capable to absorbing oxygen to generate heat. Under favorable conditions, the heat generated is sufficient to increase the rock temperature and to form spontaneous fire seats. At the same time, coal-bearing rocks emit combustible and toxic gases generated during the coal decay and the oxidation of combustible elements. To assess the possibility of the development of spontaneous ignition processes in the coal-bearing rock agglomerates that were exposed to air for a long time, the samples were taken, the constant oxygen sorption rate and the duration of the spontaneous ignition incubation period were determined. Sampling was carried out on the surface of two dumps of the open pits, as well as at different depths of the slimepit of the processing plant, which were not in operation for decades. The experiment allowed to determine the concentration and intensity of the evolution of various gases from the coal-bearing rocks at natural ambient temperature. The uneven sorption activity of the rocks on the surface of dumps contributes to forming spontaneous fire seats in the areas that are most liable to this. In addition, rock dumps for decades continue to emit methane and carbon monoxide into the atmosphere at the natural temperature of the rocks, which negatively affects the surrounding nature. In the sludge settling tank, not operated for about 60 years, the sorption activity of the sludge in relation to oxygen changes not only on the surface, but also at different depths of the settling tank. The revealed features of long-term storage of coal-bearing rocks in the dumps and slimepits should be taken into account when choosing the technologies for coal mining and processing, as well as storage of the overburden rocks and processing wastes.

Prenatal and post-hatch assessment of two strains of broiler chickens reared under high natural ambient temperatures

Pre-natal (PN) and post-hatch (PH) assessments were carried out on two broiler chicken strains to examine possible origin of strain differences and response to heat stress. One hundred and forty fertile eggs incubated for 18 days as PN and 192 day-old broiler chicks as PH; were evenly divided between two strains (Arbor Acres [AA] and Marshal [MS]). For the PN assessment (day 18, 19 and 21 of incubation), embryos were dissected and organs weighed. Liver glycogen and moisture content of the carcass and residual yolk sac were also determined. Post hatch, average body weight (ABW), average daily feed intake (ADFI) and feed conversion ratio (FCR) were measured under high natural ambient temperatures. At d 18 of incubation, proportional breast weight and yolk moisture was higher in AA than MS (P < 0.05), with the same trend observed at d 21 for yolk weight (%). Breast, gizzard, heart and liver weights were observed to increase linearly, in proportion to weight of embryo (P <0.001), between d 18 and 21 on incubation, while the inverse was observed for yolk weight (%). Post-hatch, ADFI and FCR at the end of the starter phase were lower in MS compared with AA (P < 0.05). However, at the end of the finisher phase, only ADFI was significantly influenced by strain of broiler (AA < MS; P < 0.05). Serum electrolytes and carcass characteristics did not differ between strains (P > 0.05). Phenotype differences in were manifested prior to hatch, with Marshall exhibiting advantage to Arbor Acres under high ambient temperatures.

EXPERIMENTAL STUDY ON THE COMPRESSIVE STRENGTH OF CONCRETE OF DIFFERENT STRENGTH GRADES EXPERIENCING ULTRALOW TEMPERATURE FREEZE-THAW CYCLE ACTION

Through experiments of concrete of different strength grades such as C40, C50 and C60 that experiences 0, 16 and 30 cycles of ultralow temperature freeze-thaw cycle action from 15℃ to -120℃ and -190℃, the effects of the strength grades on the concrete compressive strength are discussed. The test results show that the failure modes of the specimens with different concrete strength grades are similar and generally cone-shaped regardless of the loading at the lower or upper limit temperature, but the failure surface characteristics and so on are different. After experiencing ultralow temperature freeze-thaw cycle action, the relative concrete compressive strengths at the lower and upper limit temperatures decrease with the increase in the concrete water content. With an increase in the concrete strength grade, the relative concrete compressive strengths increase at the upper limit temperature, while the relative concrete compressive strength of every strength grade decreases with the increase in the number of freeze-thaw cycles. Although the relative concrete compressive strength in different ultralow temperature ranges increases at the lower limit temperature, there is obvious difference in the reasons for its increase. The variation trend of the relative concrete compressive strength with the increase in the number of freeze-thaw cycles is similar in a given ultralow temperature range regardless of the concrete strength grade, but there exists a difference between different ultralow temperature ranges. The influence of ultralow temperature freeze-thaw action on the concrete mechanical performance is different from that of natural ambient temperature freeze-thaw action, from which the degradation of the concrete compressive strength is much more serious. In practical engineering, the results from natural ambient temperature freeze-thaw action should not be directly applied to the design of concrete structures that undergo ultralow temperature freeze-thaw action.

The effect of varying laboratory conditions on the locomotor activity of the nocturnal Namaqua rock mouse (Micaelamys namaquensis) and the diurnal Four-striped grass mouse (Rhabdomys dilectus)

Rodents are the most common laboratory animals all over the world, however, most studies on the effects of laboratory conditions on the behavior and physiology of the study animals have been performed on traditional laboratory animals. We investigated the effects of environmental enrichment, lighting conditions and ambient temperature cycles on the locomotor activity of wild trapped, nocturnal Namaqua rock mice and diurnal Four-striped grass mice. When considering the general activity of the two species, the diurnal species showed more variability in locomotor activity than the nocturnal species. Cage enrichment differentially affected the intensity of the locomotor activity in the two species. Despite a decrease in activity, the diurnal species showed more structured rhythms in an enriched cage. Twilight conditions changed the behavior of both species, the active time of the nocturnal animal was contracted to the completely dark hours of the light cycle, while the active time of the diurnal species was extended in the longer daylight hours. The natural light appears to stabilize the entrainment of the diurnal species. The natural ambient temperature cycle caused changes in intensity of activity, but reinforced entrainment in both species. These results show that changes in laboratory housing conditions can affect the activity of captive wild animals and that these effects are species specific. By increasing our understanding of the effects of different environmental factors on the outcomes of experiments, both the results obtained, and the welfare of the captive animals may be improved.

Supplemental arginine improves intestinal morphology, but not expression of enzymes related with synthesis of polyamines in heat stress pigs

Animals exposed to high ambient temperature suffer heat stress (HS); this condition reduces feed intake and damages their intestinal epithelia, affecting nutrient digestion and absorption. Polyamines are involved in the restoration of intestinal epithelia by stimulating the proliferation of enterocytes. Because arginine is a precursor for the synthesis of polyamines, we examined the effect of supplying extra arginine in the diet on the expression of enzymes involved in polyamine synthesis and the intestinal morphology of HS pigs. This experiment was conducted when natural ambient temperature (AT) fluctuated daily from 28.2 to 38.7 °C. Twenty pigs (25.3±4.4 kg BW) were assigned to one of two treatments: control wheat‐soybean meal diet, and the control diet added with 0.20% free arginine. Pigs were fed at 0700 and 1900‐h, same amount (900 g) each time. At the end of a 21‐d trial, six pigs per treatment were sacrificed to collect intestinal mucosa samples and 5‐cm fragments from duodenum, jejunum, and ileum to analyze the intestinal morphology, and mRNA expression of spermidine/spermine N1‐acetyltransferase (SSAT), ornithine decarboxylase (ODC), and argininosuccinate synthase (ASS). Extra dietary arginine increased the villi height in duodenum, jejunum, and ileum, and the villi height:crypt depth ratio in duodenum and jejunum (P<0.01). However, no effect of extra arginine was observed on the expression of polyamine‐related enzymes (P>0.10). These results indicate that supplementing extra free arginine restores the morphology of the small intestine, but there is no clear explanation for the lack of effect of extra arginine on expression of enzymes involved in the polyamine synthesis.Support or Funding InformationCONACYT, México, CB‐2016‐01‐287052. Evonik Nutrition & Care GmbH.

The Effect of Cooled Perches on Immunological Parameters of Caged White Leghorn Hens during the Hot Summer Months.

The objective of this study was to determine if thermally cooled perches improve hen immunity during hot summer. White Leghorn pullets at 16 week of age were randomly assigned to 18 cages of 3 banks at 9 hens per cage. Each bank was assigned to 1 of the 3 treatments up to 32 week of age: 1) thermally cooled perches, 2) perches with ambient air, and 3) cages without perches. Hens were exposed to natural ambient temperatures from June through September 2013 in Indiana with a 4 h acute heat episode at 27.6 week of age. The packed cell volume, heterophil to lymphocyte (H/L) ratio, plasma concentrations of total IgG, and cytokines of interleukin-1β and interleukin-6, plus lipopolysaccharide-induced tumor necrosis factor-α factor were measured at both 27.6 and 32 week of age. The mRNA expressions of these cytokines, toll-like receptor-4, and inducible nitric oxide synthase were also examined in the spleen of 32 week-old hens. Except for H/L ratio, thermally cooled perches did not significantly improve currently measured immunological indicators. These results indicated that the ambient temperature of 2013 summer in Indiana (24°C, 17.1 to 33.1°C) was not high enough and the 4 h heat episode at 33.3°C (32 to 34.6°C) was insufficient in length to evoke severe heat stress in hens. However, cooled perch hens had a lower H/L ratio than both air perch hens and control hens at 27.6 week of age and it was still lower compared to control hens (P < 0.05, respectively) at 32 week of age. The lowered H/L ratio of cooled perch hens may suggest that they were able to cope with acute heat stress more effectively than control hens. Further studies are needed to evaluate the effectiveness of thermally cooled perches on hen health under higher ambient temperatures.

Exposure to Suboptimal Temperatures during Metamorphosis Reveals a Critical Developmental Window in the Solitary Bee, Megachile rotundata.

Metamorphosis is an important developmental stage for holometabolous insects, during which adult morphology and physiology are established. Proper development relies on optimal body temperatures, and natural ambient temperature (Ta) fluctuations, especially in spring or in northern latitudes, could result in interruptions to development. It is unclear how low-Ta exposure may affect insects that are actively developing. To understand how suboptimal Ta may affect metamorphosing insects, we used the alfalfa leafcutting bee, Megachile rotundata (Fabricius), a solitary, cavity-nesting bee that spends its juvenile and pupal stages within a brood cell. We characterized suites of physiological traits, rather than just using a singular parameter to determine effects of sublethal Ta stress. Metamorphosing M. rotundata were exposed to either constant or fluctuating low-Ta stress and compared to control bees allowed to develop normally. All bees survived and emerged as adults, but the constant low-Ta-stressed bees were affected most severely. Male constant low-Ta-stressed bees had decreased flight performance (lower metabolic rate, shorter flight bouts, decreased wing length), suggesting that the stress altered muscular or neurological development. Constant low-Ta-stressed bees also had altered activity levels, providing more support for the hypothesis that low-Ta stress causes long-term neurological defects. Exposure to fluctuating low Ta also delayed development time for both sexes; males had decreased adult life span, and both sexes had shortened wings. Together, these results provide evidence for a critical developmental window during metamorphosis and suggest that there may be severe implications for bees in the wild that are exposed to low-Ta stressors.

Mortality, production performance, water intake and organ weight of the heat stressed broiler chicken given savory (Satureja khuzistanica) essential oils through drinking water

An experiment was conducted to examine the effects on mortality, production performance, water intake (WI) and organ weight of Satureja khuzistanica essential oil (SkEO) using 720 one-day-old Arian broiler chicks in a 42-day trial. Experimental treatments were addition of 0 (control−), 200, 300, 400 and 500 mg/L SkEO or 500 mg/L polysorbate-80 (control+) into drinking water. The birds were kept under natural ambient temperatures 4–6°C above standard recommendation from days 22 to 42 of age. Addition of SkEO into drinking water at 200 and 500 mg/L decreased weight gain (P < 0.05) of the birds from days 29 to 35 of age with no differences in feed intake (FI) and feed conversion ratio (FCR) compared to control groups (P > 0.05). Addition of 300 and 500 mg/L SkEO into water increased mortality rate of the birds mainly from days 29 to 42 of age. The calculated European broiler index was greater for the birds receiving drinking water supplemented with 400 mg/L of SkEO compared with the other birds. In conclusion, administration of SkEO at 400 mg/L through drinking water to heat stressed broiler chickens may result in improved production performance efficiency.

Effects of Satureja khuzistanica essential oils in drinking water on mortality, production performance, water intake, and organ weights in broiler chickens reared under heat stress condition.

An experiment was conducted to examine the effects on mortality, production performance, water intake (WI), and organ weight of Satureja khuzistanica essential oil (SkEO) using 720 1-day-old Arian broiler chicks in a 42-day trial. Experimental treatments were addition of 0 (control−), 200, 300, 400, and 500 mg/L SkEO or 500 mg/L polysorbate 80 (control+) into drinking water. The birds were kept under natural ambient temperatures 4 to 6 °C above standard recommendation from days 22 to 42 of age. Addition of SkEO into drinking water at 200 and 500 mg/L decreased weight gain (P < 0.05) of the birds from days 29 to 35 of age with no differences in feed intake (FI) and feed conversion ratio (FCR) compared to control groups (P > 0.05). Supplementation of drinking water with 200, 300, 400, and 500 mg/L SkEO resulted in a 0.47, 4.40, 8.60, and 12.93 % decrease in WI, respectively, from days 1 to 42 of age. The calculated European broiler index was greater for the birds received 400 mg/L of SkEO in their drinking water compared with that of the other birds (P < 0.05). Pancreas percentage was increased for the birds received 200 to 500 mg/L SkEO at days 21 and 42 of age compared with that of the control− birds (P < 0.05). The gall bladder weight was 17.56, 40.50, 12.16, and 38.73 % greater for the birds received 200, 300, 400, and 500 mg/L SkEO compared with that of the control− birds, respectively. The results showed that an addition of 400 mg/L SkEO into drinking water for heat-stressed broiler chickens improves economic efficiency possibly by promoting digestion process, creating miniscule improvement in FCR and lowered mortality rate.

Population, diversity and characteristics of cellulolytic microorganisms from the Indo-Burma Biodiversity hotspot.

Forest ecosystem harbour a large number of biotic components where cellulolytic microorganisms participate actively in the biotransformation of dead and decaying organic matter and soil nutrient cycling. This study explores the aerobic culturable cellulolytic microorganisms in the forest soils of North East India. Soil samples rich in dead and decaying organic matter were collected from eight conserved forests during the season when microbes were found to be most active. Cellulolytic microorganisms were isolated using selective media in which cellulose was the sole carbon source. Population of culturable, aerobic, cellulolytic microorganisms were found to be higher at the incubation temperature that corresponds to the natural ambient temperature of the site of sample collection. Bacterial population was higher in all of the sites than fungal population. Bacterial population ranged from 1.91 × 105 to 3.35 × 106 CFU g-1 dry soil while actinomycetes and fungal population ranged from 9.13 × 102 to 3.46 × 104 CFU g-1 dry soil and 9.36 × 102 to 4.31 × 104 CFU g-1 dry soil, respectively. It was observed that though many isolates showed activity on the CMC plate assay, very few isolates showed significant filter paper activity. Three cellulolytic fungal isolates showing high FPase activity were characterised, identified and submitted to GenBank as Talaromyces verruculosus SGMNPf3 (KC937053), Trichoderma gamsii SGSPf7 (KC937055) and Trichoderma atroviride SGBMf4 (KC937054).

Melatonin circadian rhythm in three livestock species maintained in the same housed conditions

The aim of this study was to evaluate the circadian rhythm of melatonin in horses, sheep, and goats, and to compare this rhythmicity under the same conditions. Five female thoroughbred, five female Sarda sheep, and five female Sarda goats were housed in boxes equipped with an opening window. Animals were kept under a natural photoperiod and indoor ambient temperature (16–20 °C). Blood samples were collected every 2 h over 48 h period. Results showed a circadian melatonin rhythm with a nocturnal acrophase in the three species studied. In sheep and goats, acrophase was observed at about 2 h before respect to horses. All species studied showed a high robustness between rhythm 61.20 ± 7.57 and 83.60 ± 7.26, denoting a high percentage of stationarity of melatonin circadian rhythm. However, we can claim that each species has its own characteristics in melatonin secretion that must be considered in the exploration of circadian clock in different species.

Body temperature rhythms inMicrotusvoles during feeding, food deprivation, and winter acclimatization

Abstract Arvicoline voles do not possess sophisticated mechanisms to tolerate prolonged fasting and can starve to death in less than 24 h. Two experiments were performed to determine if the common vole (Microtus arvalis) and the tundra vole (M. oeconomus) have thermoregulatory adaptations to enhance survival during food deprivation or in winter, and to reveal the possible presence of ultradian body temperature (Tb) rhythms. Laboratory-bred voles (n = 5–6 for both species) were equipped with intra-abdominal data loggers that registered Tb every 10 min and were subjected to 12-h fasting periods during photophase and scotophase. In addition, 10 animals of both species were placed in outdoor cages at natural ambient temperature (Ta) and their Tb was registered at 3-h intervals between October and June. Fasted voles did not enter torpor, but the average 24-h Tb decreased by 0.2–0.5°C in winter, yielding modest energy savings. The decrease in the Tb correlated with Ta but not photoperiod and could, thus, be int...

Studying engine cold start characteristics at low temperatures for CNG and HCNG by investigating low-temperature oxidation

Engine cold start characteristics at low ambient temperatures based on first firing cycles were studied on a 1.7-l four-stroke engine for Compressed Natural Gas (CNG) and hydrogen-CNG blend fuels. In these studies engine speed, lambda ((Actual air–fuel ratio)/(Stoichiometric air–fuel ratio)), intake manifold pressure, injection pulse duration, battery voltage, intake manifold temperature, coolant temperature, and fuel line pressure at natural ambient temperature, 0°C, and −7.5°C were measured. Test results indicated for various fuels when ambient temperature decreases, lambda decreases also, but when hydrogen added to CNG (in this investigations the amount of hydrogen was 10% by volume), at similar ambient temperature, lambda increased. This implied that air–fuel mixture became leaner, which in turn could affect unburned hydrocarbons emission. Moreover, when ambient temperature decreases, after-crank-and-fire maximum engine flair speed decreases, but when hydrogen added to CNG, after-crank-and-fire maximum engine flair speed increased in comparison with pure CNG. However, when hydrogen added to CNG some instantaneous rising and falling occurred in engine speed exactly after cranking duration. This research investigated the low-temperature oxidation of CNG and the effect of adding hydrogen at low temperature to find the cause of rising and falling in engine speed. The results indicated consumption of OH by hydrogen during low-temperature oxidation of CNG. The decreased OH concentration leads to retarded heat release and has effect on engine speed.

Taking the heat: thermoregulation in Asian elephants under different climatic conditions

Some mammals indigenous to desert environments, such as camels, cope with high heat load by tolerating an increase in body temperature (T (b)) during the hot day, and by dissipating excess heat during the cooler night hours, i.e., heterothermy. Because diurnal heat storage mechanisms should be favoured by large body size, we investigated whether this response also exists in Asian elephants when exposed to warm environmental conditions of their natural habitat. We compared daily cycles of intestinal T (b) of 11 adult Asian elephants living under natural ambient temperatures (T (a)) in Thailand (mean T (a)~30°C) and in 6 Asian elephants exposed to cooler conditions (mean T (a)~21°C) in Germany. Elephants in Thailand had mean daily ranges of T (b) oscillations (1.15°C) that were significantly larger than in animals kept in Germany (0.51°C). This was due to both increased maximum T (b) during the day and decreased minimum T (b) at late night. Elephant's minimum T (b) lowered daily as T (a) increased and hence entered the day with a thermal reserve for additional heat storage, very similar to arid-zone ungulates. We conclude that these responses show all characteristics of heterothermy, and that this thermoregulatory strategy is not restricted to desert mammals, but is also employed by Asian elephants.

Refractoriness to short and long days determines the end and onset of the breeding season in subtropical goats

The objective was to determine whether refractoriness to short and long days were involved in the end and onset of the breeding season, respectively, in goats adapted to subtropical latitudes. Ovariectomized does given a subcutaneous implant constantly releasing estradiol-l7 β (OVX+E) were used in two experiments. Plasma LH concentrations were determined twice weekly. In Experiment 1, the control group remained in an open-shed pen (natural day length and ambient temperature). Two experimental groups were placed in light-proof buildings (with natural temperature variations). One group was exposed to natural simulated increasing days (winter to spring), whereas the other was exposed to a winter solstice photoperiod (10 h of light) from December 21 to April 28. In Experiment 2, the control group remained under natural day length and ambient temperature. One experimental group was exposed to natural simulated decreasing days (summer to autumn), whereas the other group was exposed to a summer solstice photoperiod (14 h of light) from June 21 to October 20. In Experiment 1, the breeding season was not prolonged in does maintained in the winter solstice day length. Mean dates of decrease in LH secretion (end of the breeding season) did not differ significantly between does exposed to natural (February 3 ± 5 d) or natural simulated photoperiod (January 26 ± 14 d) and those exposed to constant short days of winter solstice (February 4 ± 10 d). In Experiment 2, the onset of the breeding season was not delayed in does maintained in the summer solstice day length. Mean dates of increase in LH secretion (onset of the breeding season) did not differ significantly between does exposed to natural (September 7 ± 8 d) or natural simulated photoperiod (September 18 ± 10 d) and those exposed to constant long days photoperiod of summer solstice (September 24 ± 4 d). In goats adapted to a subtropical environment, we concluded that: 1) the end of breeding season was due to refractoriness to short days, and not the inhibitory effect of increasing day length; and 2) the onset of the breeding season was due to refractoriness to long days, and not a stimulatory effect of decreasing day length.