Gradual Decrease In Temperature Research Articles

Bioremediation of chlorophenol contaminated ground water

Abstract Two aerobic laboratory‐scale continuous‐flow fluidized‐bed reactors were used to study biological ground water decontamination from chlorophenols. Biomass in both reactors was enriched using synthetic chlorophenol feed. The chlorophenol degradation was monitored by inorganic chloride release (ICl), organic carbon removal and gas Chromatographic analyses. The chlorophenol concentration in Karkola aquifer, Finland remained stable through a two year period. Fluidized‐bed treatment of ground water contaminated with 44–55 mgl‐1 of chlorophenols resulted in less than 1 mgl‐1 effluent concentrations and corresponding ICl releases. 99% chlorophenol degradation was maintained even at 45 min hydraulic retention time (HRT) and 1500 gCPm‐3 d‐1 loading rate. During gradual temperature decrease from 25–30°C to 10°C within 4 months, ICl release remained stable. At 10°C, over 99 % chlorophenol removal, and effluent concentrations of less than 0.1 mgl‐1, were maintained at 5 h HRT and 240 gCPm‐3d‐1 loading rate. ...

Low temperature treatment of municipal sewage in anaerobic fluidized bed reactors

The anaerobic fluidized bed reactor (AFBR) appears to be most promising for the treatment of low strength wastes, such as municipal sewage, at low temperature, since the process is able to maintain a large mass of active microorganisms and provides effective removal of TSS. The study is divided in three parts. The objective of the first part is to characterize the effect of decreasing temperature on the performance of two mature AFBR reactors. The second part presents the data from 220 days of operation at 10°C; and in the third part two start-ups, with and without inoculum at 15°C, are evaluated. A gradual temperature decrease from 20 to 5°C, allowing the microorganisms to acclimate to the new lower temperature, did not have a great effect on effluent quality. However a great accumulation of TSS was observed in the top of the fluidized bed. At 10°C, and a hydraulic retention time of 1.5 h, 70% of T COD removal was achieved. It is possible to start-up the AFBR at 15°C without inoculation; however, at least 4 months is required to get good quality effluents.

Plasma Observations Near Neptune: Initial Results from Voyager 2

The plasma science experiment on Voyager 2 made observations of the plasma environment in Neptune's magnetosphere and in the surrounding solar wind. Because of the large tilt of the magnetic dipole and fortuitous timing, Voyager entered Neptune's magnetosphere through the cusp region, the first cusp observations at an outer planet. Thus the transition from the magnetosheath to the magnetosphere observed by Voyager 2 was not sharp but rather appeared as a gradual decrease in plasma density and temperature. The maximum plasma density observed in the magnetosphere is inferred to be 1.4 per cubic centimeter (the exact value depends on the composition), the smallest observed by Voyager in any magnetosphere. The plasma has at least two components; light ions (mass, 1 to 5) and heavy ions (mass, 10 to 40), but more precise species identification is not yet available. Most of the plasma is concentrated in a plasma sheet or plasma torus and near closest approach to the planet. A likely source of the heavy ions is Triton's atmosphere or ionosphere, whereas the light ions probably escape from Neptune. The large tilt of Neptune's magnetic dipole produces a dynamic magnetosphere that changes configuration every 16 hours as the planet rotates.

Cold Shock Susceptibility of Blue Tilapia from the Susquehanna River, Pennsylvania

Abstract A population of blue tilapia Oreochromis aureus, a native species of Africa and southern Asia, became established in the Susquehanna River, Pennsylvania, after escaping from the Brunner Island Aquaculture Facility. It appears that blue tilapias are able to survive low water temperatures during winter by congregating in thermal effluents. The objective of this study was to determine the susceptibility of the Susquehanna River population to cold shock, and the conditions necessary to eliminate these fish from the thermal effluent at Pennsylvania Power and Light's Brunner Island Steam Electric Station. Blue tilapias were acclimated to 20° and 15°C and then exposed to sublethal and lethal temperatures under three patterns of temperature reduction–rapid cold shock or one of two rates of gradual temperature decrease (1°C/h or 3°C/h) to lethal temperatures–each test lasting 96 h and involving 20 fish per test group. Among fish acclimated to 20°C and immediately exposed to test temperatures, none died at...

Fluid inclusion study of the bournac polymetallic (Sb-As-Pb-Zn-Fe-Cu...) vein deposit (montagne noire, France)

Mineralogical studies demonstrate that the Hercynian polymetallic antimony-rich deposit of Bournac can be described by four stages of ore deposition and one of partial ore remobilization. Fluid inclusion data permit calculation of the composition and temperature of the fluids associated with each stage of hydrothermal mineralization and concomitant wall-rock alteration. Stages I and II (Fe-As and Zn) are represented by moderate-salinity H2O-CO2-(NaCl) inclusions which correlate closely with early carbonate deposition. Stage III fluids which are responsible for the deposition of Pb-Sb ores are characterized by low-salinity H2O-(NaCl) inclusions. During the final stage of mineralization (IV), corresponding to the main phase of stibnite deposition, abundant aqueous inclusions confirm the continued involvement of low-salinity fluids and the intense development of potassic clays and secondary silica in the wall rocks. Homogenization temperatures suggest that the whole cycle of mineralization took place during a gradual decrease in fluid temperature of 380°–140°C. Stibnite deposition is restricted to the interval of 230°–140°C thus confirming an essentially epithermal environment. Stage V (partial remobilization) is distinguished by the presence of high-salinity CaCl2-rich inclusions which are tentatively related to Triassic barite mineralization in the region and therefore postdate the Bournac antimony ores. Homogenization temperatures for this stage range 140°–60°C.

The palynological base of stratigraphical subdivision of late cainozoic deposits of the Western Transcaucasus

The work presents the result of a palynological study of the Pliocene (Egrissian and Gurian) deposits of Western Transcaucasus. On the basis of pollen and spore assemblages the flora, the vegetation and the climate are reconstructed. The question of subdivision of the Egrissian Stage and the Gurian Horizon are considered. To the end of the first half of the Pliocene the flora of the Western Transcaucasus was developing in more or less stable palaeogeographical conditions. Climatic variations began to show themselves more clearly from the beginning of the late Pliocene. From the end of the Cimmerian to the Pleistocene, the climate of Western Transcaucasus passed through a complex evolution towards a gradual decrease of temperature and increase in precipitation. This process was complicated by a variation in the basic climatic characteristics. Periods of moderate and relatively dry climate were of short duration, suggesting a deviation from the general tendency in the evolution of the climate of the Western Transcaucasus.

Growth and Productivity of ‘Grand Rapids’ Lettuce in Diurnally Fluctuating Temperatures and Day/night Average Temperatures

Abstract The feasibility of utilizing different patterns of air temperature changes over the light and dark periods was investigated to provide a basis for greenhouse energy conservation. ‘Grand Rapids’ lettuce was grown hydroponically in microprocessor controlled growth chambers, under a light level of 325 µmol s-1m-2 PPF. Air temperatures were: a) increased from 15° to 35°C (late-peak), b) decreased from 35° to 15° (early-peak), and c) increased to 35°, then back to 25° (mid-peak) during the 16-hr light period. The late and mid-peak patterns had a gradual decrease in night air temperature, whereas the early peak pattern had a gradual increase in night air temperature. Each of these patterns averaged 25° during the light period, and 20° during the dark period. “Early-peak” plants grew poorly, whereas plants grown under the mid- and late-peak regimes grew well. Early morning diffusive resistance was similar for early- and mid-peak plants. Transpiration rates followed the air temperature changes.

Characteristics of the ITCZ over the Eastern Pacific, 5–8 June 1979

Abstract The thermal and moisture structures of the ITCZ over the Eastern Pacific-Central American region have been studied during a selected four-day period in June 1979 (FGGE). Composite structures were constructed by using soundings gathered from dropwindsondes, tropical wind observing ships, and land stations. The composited temperature structure shows that the ITCZ is cold-cored at middle levels and warm-cored at upper levels. At low levels, there is neither a distinct maximum or a minimum in the ITCZ; instead, there is a gradual decrease in temperature as one crosses the ITCZ from north to south. The moisture shows that the ITCZ, as expected, is characterized by a maximum moisture content. The maximum dew-point depression differences between the ITCZ and the environment are found at middle levels. These composites indicate that the ITCZ structure over the Eastern Pacific-Central American region on 5–8 June 1979 is similar to that of the easterly wave. This similarity in structure suggests a correspo...

The effects of fasting on core temperature, blood glucose and body and organ weights in rats.

Male Wistar rats of about 300 g body weight were fasted from 1 to 7 d. They were weighed and had their temperature taken daily. At the end of the experimental period, they were anaesthetized and blood was taken for measurement of the glucose content. The animals were killed and various organs were taken and weighed. Over the first 24 h there were striking reductions in body weight, core temperature and level of blood glucose. Throughout the succeeding days of fasting, there was a gradual decrease in body weight and core temperature, while the level of the blood glucose was maintained at about 3 mmol X l-1. The decrease in body weight and core temperature was matched by the weight loss of the liver and skeletal muscles. The heart and the kidney and spleen were not affected over the first day, but thereafter their weight declined steadily. The brain, the testes and the lungs retained their mass throughout.

Effect of detergents and fusogenic lipids on phospholipid phase transitions

The interactions of a series of amphiphilic molecules with a phosphatidylcholine/water system have been studied using differential scanning calorimetry. The addition of any of these molecules to a liposome preparation removes the pretransition endotherm. Moreover, the presence of increasing concentrations of Triton X-100 in the lipid bilayer produces a gradual decrease of the phospholipid transition temperature and enthalpy. Similar effects are produced by other detergents such as sodium dodecylsulfate, sodium cholate or octylglucoside. On the other hand, lysolecithin increases the transition temperature and leaves unaffected or increases the transition enthalpy, up to a certain lysolecithin/phosphatidylcholine ratio. These results are discussed in relation to the ability of some surfactants to induce an increase in the size of sonicated liposomes, and also in relation to previous fluorescence studies on the interaction of these detergents with phospholipid bilayers. Only those surfactants that decrease the bilayer transition enthalpy and increase the binding of fluorescent probes to the membrane hydrophobic matrix are able to induce liposome increase in size.

Higher aliphatic aldehyde polymers. VI. Poly(n‐nonaldehyde)

AbstractCrystalline poly(n‐nonaldehyde) (PNA) was prepared by anionic polymerization of n‐nonaldehyde (NA) in methylcyclohexane (MCH) with lithium tertiary butoxide (LTB) as the initiator. Normal low‐temperature conditions did not give polymer reprodusibly; however, when the polymerization was carried out with a gradual temperature decrease to −60°C holding at this temperature followed by completion at −78°C, a moderate yield of PNA was obtained. The polymer was acetate capped and characterized. Infrared and PMR spectroscopy, as well as degradation of the polymer in the presence of 2,4‐dinitrophenylhydrazine to the hydrazone, conclusively proved the chemical structure of the polymer. VPO measurements and measurement of the inherent viscosity showed the polymer to be of moderate molecular weight. PNA is highly crystalline and shows two transition regions, one corresponding to the melting of the main chain at temperatures above 120°C and one region between 50 and 80°C, which is related to the crystallization of the aliphatic side chains. PNA, although inherently brittle, can be extruded through an orifice at a temperature near the side‐chain melting temperature to give an extrudate whose x‐ray patterns show the characteristics of a fiber diagram. It is suggested that the crystal structure of the PNA is similar to that of poly(n‐heptaldehyde) but with a larger a spacing, which is expected from a longer aliphatic side chain.

The seeding of two red tide blooms by the germination of benthic Gonyaulax tamarensis hypnocysts

Complementary laboratory and field data are presented that demonstrate the seeding of a spring and a fall bloom of the toxic dinoflagellate Gonyaulax tamarensis by the temperature-induced germination of benthic hypnocysts. Nutrient, salinity, temperature and rainfall data collected before, during, and after a spring bloom in a Cape Cod salt pond indicate that germination of the overwintering hypnocysts was initiated by a temperature increase. Laboratory experiments with hypnocysts exposed to a gradual temperature increase after storage at 5 °C for four months verified this result. The fall bloom was apparently seeded by hypnocyst germination as well, but with excystment initiated by a temperature decrease from the summer level of 20–22 °C. This result was also confirmed in the laboratory using hypnocysts stored at 22 °C and subjected to a gradual decrease in temperature. The reasons for the eventual decline of both blooms are not known, but it is proposed that the motile populations were transformed into new hypnocysts that settled to the sediments. Immediately after both bloom peaks, there was a sharp decrease in the percentage of hypnocysts that germinated during laboratory incubation after isolation from fresh, unstored sediment samples. The duration of these periods of limited excystment after the declines suggests that cold storage (or overwintering) is not a required conditioning mechanism prior to germination but that a prolonged period of conditioning at higher temperatures will suffice. Finally, data are presented that suggest that the extreme localization of the blooms within the salt pond was due to limited tidal advection of the motile population and the favourable trace metal chemistry of the estuarine environment compared to the adjacent coastal waters.

The effect of changes in ambient temperature on spontaneous activity in skipjack tuna

1. 1. The spontaneous activity of skipjack tuna tended to remain unchanged in the face of a gradual decrease in ambient temperature from 24 to 16°C. 2. 2. One fish cooled further showed a rapid decline in activity at 14°C and died at 13°C.

SOME PHYSIOLOGICAL RESPONSES OF SHEEP TO SHORT-TERM COLD EXPOSURE

An experiment was conducted with shorn, mature wethers to study the short-term effects of a low ambient temperature on jugular vein temperatures, rectal temperatures, packed cell volumes, eosinophil counts, and the plasma concentrations of sodium, potassium, calcium, magnesium, and glucose. The sheep were placed singly in a chamber in which they were subjected during consecutive 3-day periods to air temperatures of 20.6 ± 1.0, 1.3 ± 1.5, and 19.2 ± 2.0 °C. In the cold period, an immediate and marked downward fluctuation in jugular blood temperature was followed, after 12 hours, by a more gradual decrease in rectal temperature. Eosinophil counts were also markedly decreased. Plasma sodium and glucose concentrations increased in the cold. The plasma potassium concentration fluctuated upward in the first 12 hours of the cold period, while the plasma magnesium and calcium concentrations were not significantly affected. The packed cell volume increased during cold exposure, and it appeared that some of the electrolyte changes observed may have been due to hemoconcentration.

Responses of bats from temperate regions to changes in ambient temperature.

1. Responses to upward and downward changes in ambient temperature from 5° C. were studied in dormant bats of the species E. fuscus, P. subflavus, M. sodalis, M. lucifugus and L. borealis. Rectal temperatures and heart rates were recorded.2. Except for L. borealis which did not arouse until ambient temperature reached about 20° C., all species responded by arousal from dormancy when the temperature was increased to 15° C.3. The effects of decreasing ambient temperature varied considerably among species. E. fuscus invariably aroused from dormancy. L. borealis never aroused but showed a thermoregulatory response by increasing its metabolism to compensate for the increase in heat loss. The responses of the other species depended upon the abruptness of the temperature change. Abrupt lowering of ambient temperature tended to induce arousal in M. lucifugus and M. sodalis, whereas these species responded similarly to L. borealis when exposed to gradually decreasing temperature. P. subflavus usually aroused in response to a gradual decrease in ambient temperature, but seemed unable to arouse in response to abrupt lowering of temperature.4. Bats of the species L. borealis, M. lucifugus and M. sodalis supercooled to -5° C. showed cessation of breathing, but slow heart beats continued for several hours. Passive rewarming was necessary for survival.5. Many of the known differences in the ecology of the studied species of bats are reflected as differences in their response to changes in ambient temperature in the laboratory.

Some Oceanographic Features of the Northeast Pacific Ocean during August 1955

Physical oceanographic data from the international NorPac survey of August 1955, in the area north of Lat. 45°N and east of Long. 161°W, were examined. The temperature, salinity, and density distribution and structure from the surface to 2000 m are discussed.The temperature structure showed an isothermal layer to about 30 m depth, a marked thermocline to about 100 m depth, a temperature inversion in most of the area, and below this a gradual temperature decrease into the abyss. At all depths the water was coldest in a "cold core" centered about 100 miles south of Kodiak and the Shumagin Islands. From there the temperature increased at each level in all directions.The salinity structure showed an isohaline layer to about 100 m depth, a marked halocline to about 200 m depth, and below this the salinity increased slightly into the abyss. The salinity structure did not coincide with the temperature structure.The density structure showed an isopycnal layer to about 30 m depth, a pycnocline associated with the thermocline, a second isopycnal layer, a second pycnocline associated with the halocline, and below this the density increased slightly into the abyss.Variations in these structures throughout the region are discussed in some detail.There is no horizontal isosteric level in the 2000 m of depth. It is concluded that there is no level of "no net motion" in this range, but a reference level of 2000 decibars (db) for dynamic calculations is more acceptable than the usual 1000-db level. A new procedure is introduced to extend the reference level into the bottom in near coastal areas.The geostrophic currents were calculated. There was a major latitudinal drift from the west into the central part of the area. It veered northward and continued around the Gulf of Alaska, forming the Alaska Gyral, and left the area to the westward, as an intensified current (Alaskan Stream) close along the Alaskan Peninsula. This intensification is probably due to conservation of absolute vorticity through changing latitude.The circulation pattern extended to at least 2000 m depth, and probably to the bottom. It transported about 17 million m3 of water per second. There were a number of eddies in the system, some of which were observed on earlier surveys.The major flow pattern was not wind-generated within the region. The influence of local winds was limited to the upper 200 m of depth. In some areas it aided the flow, and in others retarded it.There is evidence to show that two chains of seamounts influenced the current pattern according to the Sverdrup concept. Since the major portion of these is below 2000 m depth it is concluded that currents exist in the abyss, in essentially the same direction as at the upper levels.

Some Oceanographic Features of the Northeast Pacific Ocean during August 1955

Physical oceanographic data from the international NorPac survey of August 1955, in the area north of Lat. 45°N and east of Long. 161°W, were examined. The temperature, salinity, and density distribution and structure from the surface to 2000 m are discussed.The temperature structure showed an isothermal layer to about 30 m depth, a marked thermocline to about 100 m depth, a temperature inversion in most of the area, and below this a gradual temperature decrease into the abyss. At all depths the water was coldest in a cold core centered about 100 miles south of Kodiak and the Shumagin Islands. From there the temperature increased at each level in all directions.The salinity structure showed an isohaline layer to about 100 m depth, a marked halocline to about 200 m depth, and below this the salinity increased slightly into the abyss. The salinity structure did not coincide with the temperature structure.The density structure showed an isopycnal layer to about 30 m depth, a pycnocline associated with the ...

Action potential form change of the area striata in hypothermia

The effect of temperature on the evoked response of the visual cortex to single photic stimulation of the retina and single electrical stimulation applied to the optic nerve at temperatures ranging from 37 to 15° was investigated. In the experiments completely isolated and artificially perfused heads of cats are used. The latencies of the evoked responses to photic and electrical stimulation increased continously with decreasing temperatures. The amplitudes of the evoked responses to photic stimulation initially remained the same with a gradual decrease of temperature, later on decreasing and finally disappearing was obtained at 18–17°. However, the amplitude of the evoked responses to electrical stimulation increased with decreasing temperatures reaching a maximum at 26–23°, thereafter decreased again and finally also disappeared when the temperature reached 18–15°. Sometimes, at low temperatures, some additional deflections are to be find between the deflections 4 and 5 of the evoked response to electrical stimulation.

THE FUNCTION OF THE ADRENAL CORTEX

When the adrenal glands are removed from laboratory animals, symptoms of deficiency develop, which may be summarized as follows: The first notable change is usually a loss of appetite, which is soon followed by nausea, vomiting, increased peristalsis and eventually bloody diarrhea. Associated with these changes are profound weakness of the muscles and a listless stupor, or, in some animals, restlessness and marked salivation, with clonic movements and general convulsions similar to those observed in hypoglycemia induced by insulin. There is a gradual decrease in body temperature and a decrease in the basal metabolic rate. Continuance of the state of adrenal deficiency is invariably associated with a decrease in blood pressure to the death level, an increase in the hematocrit reading and a progressive decrease in the volume of the circulating blood. Soon after removal of the adrenal glands there is a marked and continuous increase in the concentrations of

Changes in color temperature of tungsten-filament lamps at constant voltage

Seasoned lamps, operated at constant voltage, gradually decrease in color temperature because of evaporation of the filament. Since the current does not decrease enough to correspond to an appreciable change in filament temperature, this decrease in color temperature is ascribed in large part to the accumulation of the familiar brown film on the inside surface of the bulb. The size and shape of the bulb is, therefore, important; each type must be separately investigated. Results are given for five types. The effect of operating seasoned lamps is a gradual decrease in color temperature, linear with time, which, like the rate of evaporation of tungsten, was found for 400-watt projection lamps, to be nearly proportional to the thirtieth power of the temperature. The effect of seasoning new lamps for one hour at about rated voltage was a rise in color temperature from 3050° to about 3140°K, approximately half of which occurred in the first three minutes.