කලකට පෙර ශ්රී ලංකාවේ අයිස් නිශ්පාදන කර්මාන්තය ගැන කල අැගයීමක කොටසක්. ශීතකරණයේ බඳුන් වල අැතිවෙන අයිස් තට්ටු, වල් සහ වැව් වල මතුපිට අයිස් සහ ග්ලේසියර් ස්වාභාවයෙන් වායුගෝල පීඩනයේ අැතිවන අයිස් කීපයක්. මෙම අයිස් වල ව්යහය හා තාප හා භෞතික ගුණ මෙම සටහනේ තියනවා.
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This is an extract from a study I did about the Ice Making Industry of Sri Lanka. Common types of Ice include vertically growing ice such as that found on the sides of containers, horizontally growing ice such as that formed on the top of lakes and ice then has randomly oriented grains in every direction similar to Glacier ice. This post is about the micro-structure of common Ice and its physical and thermal properties.
Hexagonal Ice - ෂඩස්ර ස්ඵටික අයිස්
Ordinary Ice and even snow takes the form of hexagonal ice (ice Ih). Ice Ih is formed when water is cooled at 0°C and at standard atmospheric pressure. There are over 13 variations of the crystalline structure of ice. The non-cyrstalline glass-like Amorphous Ice is formed when water is cooled at a high pressure and high cooling rate.5
එදිනෙදා භාවිත වන අයිස් සහ හිම, ෂඩස්ර ස්ඵටික ව්යහයක් ගන්නවා. මෙය අයිස් Ih ලෙස දැක්වේ. සම්මත වායුගෝල පීඩනයේ 0°C උෂ්ණනත්වයේ පවතින ජලය, සිසිල් කරද්දී අයිස් Ih හැදෙනවා. අයිස් වල ස්ඵටක අවස්ථා 13 කට වඩා පවතිනවා. අධි පීඩනයක් සහ අධි සීග්රතසවකින් ජලය සිසිල් කර විට, ස්ඵටික ව්යහයක් නොගන්නා වීදුරු මෙන් විනිවිද පෙනෙන අැමෝර්ෆස් අයිස් හැෙදනවා.
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This is the model developed by Linus Pauling in 1935. The oxygen atoms are shown by open circles and hydrogen atoms shown by dark circles.5
මෙම ස්ඵටික ව්යහය ලීනස් පෝලිං විසින් 1935දී ඉදිරිපත් කරා. හයිඩ්රජන් පරමානු තද පාටින් දැක්වේ.
While there are many other phases of ice there are also some varieties of the ice Ih phase.
SI Ice
S1 ice occurs when ice forms platelets lying on the surface with the c-axis vertical forming columnar grains. This is then considered a vertically growing ice such as that found on the sides of containers.
S2 Ice
If the ice is formed more rapidly, we have randomly oriented grains which grow perpendicular to the c-axis. This then represents a horizontally growing ice such as that formed on the top of lakes known as S2 ice.
T1 Ice
Polycrystalline ice then has randomly oriented grains in every direction and is known as T1 ice. This type of ice is very similar to Glacier ice.
- The Many Phases of Ice5
Other Phases of Ice
There are several other phases of ice. See phase diagram of ice-water system. Wikipedia also has a section on various other phases of Ice.2 Most of theses phases of Ice are quite rare. Most can only be created in laboratories.
"Ice Ic is a very popular structure for theoretical modeling of ice because its high symmetry simplifies calculations."5
Thermal & Physical Properties of Ice Ih / අයිස් Ih වල තාප භෞතික ගුණ
Source: The Engineering ToolBox6
| Temperature උෂ්ණත්වය °C |
Density ඝනත්වය kg/m3 |
Thermal Conductivity තාප සන්නායකතාව W/mK |
Specific Heat විශිෂ්ඬ තාපය kJ/kgK |
|---|---|---|---|
| 0 | 916.2 | 2.22 | 2.050 |
| -5 | 917.5 | 2.25 | 2.027 |
| -10 | 918.9 | 2.30 | 2.000 |
| -15 | 919.4 | 2.34 | 1.972 |
| -20 | 919.4 | 2.39 | 1.943 |
| -25 | 919.6 | 2.45 | 1.913 |
| -30 | 920.0 | 2.50 | 1.882 |
| -35 | 920.4 | 2.57 | 1.851 |
| -40 | 920.8 | 2.63 | 1.818 |
| -50 | 921.6 | 2.76 | 1.751 |
| -60 | 922.4 | 2.90 | 1.681 |
| -70 | 923.3 | 3.05 | 1.609 |
| -80 | 924.1 | 3.19 | 1.536 |
| -90 | 924.9 | 3.34 | 1.463 |
| -100 | 925.7 | 3.48 | 1.389 |