EFFECT OF COOLING RATE ON THE FREEZING TEMPERATURES OF SUPERCOOLED INSECTS

1966 ◽  
Vol 44 (4) ◽  
pp. 655-659 ◽  
Author(s):  
R. W. Salt
Keyword(s):  
Cooling Rate ◽  
Water Samples ◽  
Freezing Temperature ◽  
Supercooling Point ◽  
Cephus Cinctus ◽  
Standard Rate ◽  
Rate Of Cooling ◽  
The Mean ◽  
Freezing Temperatures

Cooling rate affects the freezing temperature of water samples and of insects. Doubling the rate of cooling lowers the mean supercooling point of Cephus cinctus larvae 0.24 °C. Adoption of a standard rate of cooling of 1° per minute, or adjustment of other rates to this basis, is proposed.

The supercooling and freezing of small water droplets falling in air and other gases

1968 ◽  
Vol 302 (1471) ◽  
pp. 437-452 ◽  
Keyword(s):  
Droplet Diameter ◽  
Thermal Inertia ◽  
Supercooled Water ◽  
Freezing Temperature ◽  
Small Water ◽  
Standard Rate ◽  
Rate Of Cooling ◽  
The Mean ◽  
Additional Support ◽  
Good Agreement

The freezing of individual droplets of very pure supercooled water, ranging in diameter from 5 to 120 μ m, has been photographed and measured as they fall through a vertical tempera­ture gradient established in cold, purified helium, air and other gases. From measurements made on a few hundreds of droplets of the same size, it is possible to deduce the median (or mean) freezing temperature of the group and the statistical spread about the mean temperature. When the ‘observed’ freezing temperatures are corrected for the thermal inertia of the falling droplets and adjusted to a standard rate of cooling, they are in good agreement with earlier work in which the droplets were cooled in a liquid supporting medium. The observed variation of freezing temperature with droplet diameter may be satisfactorily interpreted in terms of the theory of homogeneous nucleation of supercooled water if the specific surface free energy of the crystal/liquid interface is taken to be 20 erg cm -2 between —35 and —40°C. The experimental results are also consistent with, and offer additional support for, the recent Némethy-Scheraga statistical thermodynamical treatment of the ‘flickering-cluster’ model of liquid water.

scholarly journals An approximation for homogeneous freezing temperature of water droplets

2015 ◽  
Vol 15 (21) ◽  
pp. 31867-31889
Author(s):  
K.-T. O ◽  
R. Wood
Keyword(s):  
Experimental Studies ◽  
Freezing Temperature ◽  
Ice Nucleation ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Water Droplets ◽  
Wide Range ◽  
The Mean ◽  
Freezing Temperatures ◽  
Homogeneous Freezing

Abstract. In this work, based on the well-known formulae of classical nucleation theory (CNT), the temperature TNc = 1 at which the mean number of critical embryos inside a droplet is unity is derived and proposed as a new approximation for homogeneous freezing temperature of water droplets. Without consideration of time dependence and stochastic nature of the ice nucleation process, the approximation TNc = 1 is able to reproduce the dependence of homogeneous freezing temperature on drop size and water activity of aqueous drops observed in a wide range of experimental studies. We use the TNc = 1 approximation to argue that the distribution of homogeneous freezing temperatures observed in the experiments may largely be explained by the spread in the size distribution of droplets used in the particular experiment. It thus appears that this approximation is useful for predicting homogeneous freezing temperatures of water droplets in the atmosphere.

Cold tolerance of the spring-feeding larvae of the eyespotted bud moth,Spilonota ocellana(Lepidoptera: Tortricidae)

2017 ◽  
Vol 149 (3) ◽  
pp. 291-299 ◽  
Author(s):  
J.A. Swain ◽  
G.J.R. Judd ◽  
J.S. Cory
Keyword(s):  
Low Temperature ◽  
Larval Mortality ◽  
Malus Pumila ◽  
Supercooling Point ◽  
Spring Frost ◽  
Temperature Thresholds ◽  
The Mean ◽  
Freezing Temperatures ◽  
Freeze Tolerant ◽  
Lower Lethal Temperature

AbstractIn this study, we explore the low-temperature thresholds of a pest of apple (Malus pumilaMiller; Rosaceae), the eyespotted bud moth,Spilonota ocellanaDenis and Schiffermüller (Lepidoptera: Tortricidae), in the context of spring frost.Spilonota ocellanaoverwinters as a larva, resuming activity and feeding early in the growing season when it could be vulnerable to unexpected freezing temperatures. We determined that the mean supercooling point of spring instars did not differ for larvae within or outside leaf shelters and ranged from −9.1±0.2 °C for fourth instars, to −7.9±0.2 °C for sixth instars. Larval weight increased with instar and was positively related to the supercooling point. As some insects are freeze tolerant and able to recover from freezing, we also exposed larvae to brief freeze events between −4.5 °C and −9.5 °C and found that the median lower lethal temperature, was −7.3±0.4 °C across all instars; indicating thatS. ocellanaspring instars are susceptible to freezing temperatures above their supercooling point. These low-temperature thresholds suggest that in the spring, S. ocellanalarvae are chill susceptible, and a hard frost (<−7 °C) would be necessary to cause significant larval mortality.

Non-isothermal crystallization behavior of spinel crystals in FeO-SiO2-TiO2-V2O3-Cr2O3 slag

2018 ◽  
Vol 116 (1) ◽  
pp. 110
Author(s):  
Lixiong Shao ◽  
Jiang Diao ◽  
Wang Zhou ◽  
Tao Zhang ◽  
Bing Xie
Keyword(s):  
Cooling Rate ◽  
Crystallization Behavior ◽  
Crystal Size ◽  
Growth Mechanisms ◽  
Vanadium Slag ◽  
Growth Behaviour ◽  
Temperature Range ◽  
Chromium Spinel ◽  
Mean Diameter ◽  
The Mean

The growth behaviour of spinel crystals in vanadium slag with high Cr2O3 content was investigated and clarified by statistical analyses based on the Crystal Size Distribution (CSD) theory. The results indicate that low cooling rate and Cr2O3 content benefit the growth of spinel crystals. The chromium spinel crystals firstly precipitated and then acted as the heterogeneous nuclei of vanadium and titanium spinel crystals. The growth mechanisms of the spinel crystals at the cooling rate of 5 K/min consist two regimes: firstly, nucleation control in the temperature range of 1873 to 1773 K, in which the shapes of CSD curves are asymptotic; secondly, surface and supply control within the temperature range of 1773 to 1473 K, in which the shapes of CSD curves are lognormal. The mean diameter of spinel crystals increases from 3.97 to 52.21 µm with the decrease of temperature from 1873 to 1473 K.

scholarly journals Assessment of heavy metals contamination and associated risks in shallow groundwater sources from three different residential areas within Ibadan metropolis, southwest Nigeria

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Saheed Adekunle Ganiyu ◽  
Abimbola Temitope Oyadeyi ◽  
Azeem Adedeji Adeyemi
Keyword(s):  
Heavy Metals ◽  
Cancer Risk ◽  
Urban Area ◽  
Ecological Risk ◽  
Water Samples ◽  
Risk Index ◽  
Shallow Groundwater ◽  
World Health ◽  
Southwest Nigeria ◽  
The Mean

AbstractThis study has been conducted to appraise the concentrations of selected heavy metals and total dissolved solids (TDSs) in the drinking water from shallow wells in parts of Ibadan metropolis, southwest Nigeria. Fifteen (15) water samples were collected from three representative residential locations [traditional core area (TCA), peri-urban area (PUA), and urban area (UA)] for geochemical analysis. Heavy metals and TDS were analyzed with the aid of atomic absorption spectrophotometer and calibrated meter, respectively. The mean concentration (mg/L) of Zn, Pb Mn, Fe, and Cd has been 3.930, 0.658, 0.0304, 1.698, and 0.501, respectively, and as a consequence, the order of abundance of studied metals was Zn > Fe > Pb > Cd > Mn. Concentrations of Zn, Fe, Pb, and Cd were higher than recommended standards in 60%, 86.7%, 100%, and 100% of groundwater samples, respectively. However, at all points tested, the mean concentrations of Mn and TDS in water samples lie within the safe limits set by World Health Organization. The evaluation of geoaccumulation index (Igeo), enrichment factor (EF), and contamination factor suggests that representative water samples were low-to-moderate contamination. The potential ecological risk index advocates low-to-moderate ecological risk in TCA and PUA, while it demonstrated exclusive “moderate” risk in UA. Further, the range of pollution load index (PLI) (0.55–1.32) in both TCA and PUA shows nil-to-moderate pollution status, while PLI values > 1 in UA indicate moderate contaminated state. The degree of contamination in groundwater showed the following trends: UA > TCA > PUA in the study area. Moreover, the results of EF and quantification of contamination of analyzed metals in water samples indicate geogenic and anthropogenic inputs. The contribution of studied metals to the incidence of non-cancer risk via oral intake within the residential sites follows the order: cadmium > lead > zinc > iron > manganese. The hazard index as a result of ingested heavy metals for the three population classes surpasses the acceptable range in the order of infant < child < adult. Cadmium and lead made considerable impact to the estimation of cancer risk in the study area for the three human population categories. Factor analysis extracted only one component that explained 94.64% of the entire variance, while cluster analysis identified three distinct groups based on similar water quality characteristics. Based on the findings of the study, awareness programs toward protecting the shallow groundwater sources should be launched, encouraged, and sustained. Moreover, the study suggests better hygienic practices and pre-treatment of contaminated water before consumption.

Development of Reformative Surgery Method Using Partial Freezing for the Liver

2006 ◽  
Vol 128 (6) ◽  
pp. 862-866
Author(s):  
M. Takahashi ◽  
S. Nomura ◽  
M. Jindai ◽  
S. Shibata ◽  
X. Zhu ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Degrees Of Freedom ◽  
Operation Time ◽  
Basic Research ◽  
Freezing Temperature ◽  
The Finite Element Method ◽  
Porcine Liver ◽  
Liver Sample ◽  
Peltier Module ◽  
Increment Rate

To minimize surgical stresses including blood loss and operation time to the patients during hepatic resection, we studied the feasibility of a combination of a partial liver freezing technique and shape-memory alloy, which also enables a free-designed resection curve. In this surgical procedure, the region surrounding a tumor in the liver is frozen to excise and prevent hemorrhage. The liver was frozen by a Peltier module. The effects of cooling rate and freezing temperature on the excision force that arise between a scalpel and the liver are carried out experimentally as a basic research for partial freezing surgical procedures. A porcine liver was used as a liver sample. The physical properties were estimated by using the finite element method based on the heat transfer characteristics of the liver. Isolation of the liver was conducted using a scalpel attached to the end-effector of a 3 degrees of freedom robot. In the experiments, the minimum excision force was obtained at a temperature between 272K and 275K; therefore, it is preferable that the liver be excised within this temperature range. Lowering of the cooling rate decreases the excision force even if the temperature of the liver remains unchanged. The lower the temperature of the liver is, the larger the increment rate of excision force is with regard to the cooling rate.

Theoretical Aspccts of Cloud Drop Distributions

1949 ◽  
Vol 2 (3) ◽  
pp. 376 ◽  
Author(s):  
EB Kraus ◽  
B Smith
Keyword(s):  
Cooling Rate ◽  
Drop Size ◽  
Initial Temperature ◽  
Theoretical Study ◽  
Air Pressure ◽  
Size Spectrum ◽  
Condensation Nuclei ◽  
Cloud Drop ◽  
Rate Of Cooling

A theoretical study indicates that the number and size of the drops formed in a cloud vary with the rate of cooling, the initial temperature, and the air pressure. The faster the cooling rate, the lower the initial temperature, and the lower the altitude, the greater is the number of drops and the smaller their size. The drop size spectrum also depends, to a large extent, on the number of available condensation nuclei. Furthermore, it tends to be widened by sedimentation and turbulence.

Stable isotope geochemistry of Oxygen and Hydrogen: A case study of the Satluj River Basin, India  

2021 ◽  
Author(s):  
Akhtar Jahan ◽  
Mohd Usman Khan ◽  
Nachiketa Rai ◽  
Abhayanand Singh Maurya ◽  
Sudhir Kumar
Keyword(s):  
Stable Isotope ◽  
River Water ◽  
Water Samples ◽  
Hydrological Cycle ◽  
Indian Subcontinent ◽  
Monsoon Season ◽  
Isotope Analysis ◽  
Mean Value ◽  
Isotopic Analyses ◽  
The Mean

&lt;p&gt;Stable isotope analysis of hydrogen and oxygen is one of the important methods used to model the hydrological cycle. Oxygen and hydrogen isotopic investigation of river water, its tributaries, and groundwater of its catchment from the Satluj basin was undertaken to estimate the contributions of the main sources comprising discharge during major periods throughout a hydrologic year.&lt;/p&gt;&lt;p&gt;Estimation of the snow/glaciers melt contribution is also very important for tracing the sources and processes regulating the flow from the provenance and reservoirs in the context of global warming, for estimating flood flow, and for other water resource development activities in large parts of the Indian subcontinent. Water samples were collected during the non-monsoon season at increasing altitudes. In this work, in addition to stable isotopes, we also assessed the water quality using various physicochemical parameters and geochemistry of the water.&lt;/p&gt;&lt;p&gt;From isotopic analyses of river water samples, the mean value of the &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O was found to be ~ -13&amp;#8240;, and the mean value of &amp;#948;D was found to be~ -85&amp;#8240;. For the samples from Satluj tributaries, the mean value of the &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O was ~ -11&amp;#8240;, and the mean value of &amp;#948;D was ~ -69&amp;#8240;. A mean value of -8.4&amp;#8240;, was found based on the &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O measurements of the groundwater samples, while the average &amp;#948;D value was found to be ~ -55&amp;#8240;.&lt;/p&gt;&lt;p&gt;For the mainstream and tributary, LWL, y = 8.2604x +20.208, and range of d-excess (&gt;10&amp;#8240;) and y = 8.2079x + 22.182 and d-excess &gt; 10&amp;#8240; indicates a system recharged by sources of recycled moisture derived from continental sources in addition to monsoonal climates. For the groundwater data, the slope is 6.7, and d-excess ranges from 7&amp;#8240; to 17&amp;#8240;. These observations are suggestive of the monsoonal source of Indian Ocean precipitation that has experienced significant evaporation during the non-monsoon season.&lt;/p&gt;&lt;p&gt;Our new data clearly shows that the surface water whether mainstream, tributary, and groundwater isotopes are homogenized from regional trends in precipitation, modified by evaporation, and are thus greatly influenced by latitude, elevation, and patterns of climate.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Assessment of Polycyclic Aromatic Hydrocarbons in Underground Water around the Viccinity of Balogun-Biiro Dump Site, Oke Bale, Osogbo, Nigeria

2013 ◽  
Vol 2 (1) ◽  
Author(s):  
T A Adedosu
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Water Samples ◽  
Underground Water ◽  
Dump Site ◽  
Diagnostic Indices ◽  
Polycyclic Aromatic ◽  
The Mean ◽  
Mean Concentration ◽  
Significant Concentration

Well-water samples were collected from the vicinity of Balogun–biiro dump site located in Okebaale Osogbo, Osun state, Nigeria. The polycyclic aromatic hydrocarbons were determined qualitatively and quantitatively using GC-FID. The concentration of polycyclic aromatic hydrocarbons in the water samples ranged from 0.01235 µg/kg to 0.05365 µg/kg with mean concentration ranging from 0.00094 µg/kg to 0.00335 µg/kg respectively. The highest concentration of ∑16 𝑃𝐴𝐻𝑠was recorded in S6 and it was observed that there is decline in polycyclic aromatic hydrocarbons concentrations from point of water pollution. There was a significant concentration of both the lower and higher rings polycyclic aromatic hydrocarbons in the samples. These distributions as well as various polycyclic aromatic hydrocarbons diagnostic indices calculated showed that the sources of polycyclic aromatic hydrocarbons in the samples were both petrogenic and pyrogenic. The mean concentrations of polycyclic aromatic hydrocarbons recorded in the water samples showed a little bit enhanced values than the recommended tolerable limits, which indicated some level of pollution in the water samples

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