Crevices in Cracked Concrete

Wow, this is a late post! I'm really sorry for such a delay; I had a terrible cold that drained so much energy out of me. Anyway, this blogpost is  something I've been wanting to write for quite a while! It's a bit different from the previous ones - it's about cracked concrete in winter.


It was early December when I first noticed the cracks in the concrete around school campus. I had just finished school and was on my way to the school gate, when I saw deep cracks at the edges. I pointed them out to my friend, but she didn't think they were that different from before. But I continued to observe the concrete around the manholes, the parking spaces and the school field...the entire campus, which suddenly seemed to crumble away like a falling kingdom. 

As winter progressed, it became clearer: in some areas, the concrete was sinking but in others, the concrete was rising, making huge, uneven crevices through which rainwater and snow fell. It became so bumpy that a bicycle ride through these areas was bound to get a little shakier.

So, what makes concrete crack? I've never seen any concrete road that's completely free of cracks...because all concrete has a tendency to crack. It has a low tensile strength while it has a high compressive strength (the former is only 10% ~ 20% of the latter). Another characteristic - a low thermal expansion coefficient - means that it is not flexible enough to expand or contract according to temperature. That is why the freeze-thaw cycle in the winter is a popular explanation for concrete cracking. With the changes in temperature and humidity, the concrete distends and shrinks, making irregular cracks that are difficult to maintain. 

I recently saw the school maintenance staff walking around the campus, measuring the depth and length of the cracks with a paper ruler. Perhaps they are planning on getting new concrete? It won't be happening any time soon, though; snow and rainfall are still sporadic yet frequent, and a new coat of concrete in such conditions is not going to produce favorable results-!






The next two pictures don't show any cracks but contain the little beauties I saw on other parts of concrete :) 

http://www.angieslist.com/articles/why-concrete-cracks-and-how-prevent-it.htm
http://civil-engg-world.blogspot.kr/2009/04/relation-between-compressive-and.html
http://en.wikipedia.org/wiki/Properties_of_concrete#Cracking

Silver Grasses...and Fine Dust - Yangjaecheon

I recently took a little stroll along Yangjaecheon - something I hadn't done in a while. Terribly preoccupied with school exams among so many things, I had waited an entire week for the day, eagerly anticipating a winter wonderland of snow, ice, evergreen trees and winter birds. To my utter dismay, however, the previous night's news and friends' anxious worries alerted me that the smog of fine particles (atmospheric particulate matter) heading from China would settle over Seoul the next day. I was on the verge of giving it up...but I "triumphantly" strode out into the brilliant winter sunshine (however concentrated the air may be of fine dust). I'm not exactly sure what made me do it, but the biggest reason was that I really wanted to see Yangjaecheon on such a day. It might have been a stupid thing to do, but my carefree and naive self couldn't have cared too much about it.

*      I'm sure most of us are familiar with the health implications that fine particulate air pollution brings. But far less are aware of the particles themselves and the impact they have on the Earth's climate! 
        Atmospheric particulate matter is suspended in the air as atmospheric aerosol. Aerosols are - put simply - a bunch of tiny particles and droplets in the atmosphere. Whereas some are dark-colored, others have shiny surfaces and can reflect the energy from the Sun back to space. Thus, aerosols are capable of imposing a cooling effect on the earth. Note that the the climatic effects happen on a regional scale. (Ex. The failure of the Indian Monsoon is thought to be attributed to the lack of evaporation of water in the Indian Ocean due to anthropogenic aerosol) 
       Volcanoes are a natural source of aerosol - after erupting, there is a temporary cooling effect over the area. Engineers are pondering whether artificial injections of aerosol of similar composition could help curb global warming. However, the effect of atmospheric particulates still remains unclear and so such measures are being debated over.

Ever so different from Summer

I went down by my usual route, and paused before I went under the bridge. I remembered a picture I had taken last summer of the same place (on blog post  'The Sunflowers of Yanjaecheon' http://ecoheal-ing.blogspot.kr/2013_08_01_archive.html) This time, there were no mothers heading down with their babies in prams; fine particles are especially harmful for babies' health. Even with the sunshine, it felt cold with the branches dry and bare and few hanging leaves parched and shriveled. 

Something nostalgic in how
the tree held itself

A maple tree was almost a rusty brown. It still seemed beautiful to me. The majority of leaves above were completely dried up, yet there was that new shade of scarlet among other leaves - something between copper, henna and russet. With an intensity that only time can give, there was something nostalgic in how the tree held itself, not letting go of its leaves when its colors were fading away.

Looking a little hazy, maybe?

As I walked along the stream, I noticed that not many people were around. The image of invisible dust diffusing through my arterioles and bronchioles flashed. The sky didn't seem too different  - I could still see the clear sky-blue and birds flying past. The buildings seemed a little hazier than usual, but that was the only difference I could feel.











Suddenly, I held my breath.

A sea of Lilliputian fluffs - from café-au-lait beige to shimmering pale grey - rippled before me. The stalks were almost of a coppery tan, yet the silky flowers were of a pearly glow. Waves went through hundreds of Miscanthus sinensus (Eulalia grass, maiden grass, zebra grass, porcupine grass) each time wind blew. The cold gust of air was stinging against my flushed cheeks, yet the flowers gracefully swayed, sending troughs and crests through . Their satiny fibers evoked warmth and affection, startlingly distant from the harsh weather. 

 I went to Yangjaecheon anticipating something that only winter can give, and I was right.  It wasn't exactly what I hoped it would be, nor could I be completely relaxed breathing in the contaminated air. But the silvery grasses made up for it. Totally.

As I type the last few words for this blog post, I'm only a quarter away from the beginning of 2014 in local time!

Happy New Year, everyone! 
More refreshing posts and updates are to come!

Into The White

      Now that it's mid-December, the tops of buildings, trees, and benches are covered with "caster sugar", as I used to call it. The trees are not completely bare yet; some of the dried-up leaves are still hanging on. Outside the window, I spot a thin tree standing in snow with its leaves scattering over the white. 

When some of the snow melts away, it leaves footstep-shaped patches of snow. It reminds me of tales of snowmen, walking around when we don't see them. 

In Seoul, these days, the temperatures go down to approximately -12°C in early morning. But as the day warms to about  3°C, the fluffy snow melts to slushy lumps of ice. 

I remember an article I read on BBC News a few months ago - ancient artifacts were discovered on Norwegian mountains due to rapidly melting snow patches. Snow is a really curious thing; snowflakes - as small as 2-4 mm in diameter - cast thin sheets layer by layer on whatever they are falling on, sometimes becoming thick enough to preserve Neolithic weapons and Iron Age tunics through the ages. 

http://www.bbc.co.uk/news/science-environment-23849332

Winter Knocking On Our Door

Last week came the first snowfall of the year. Sitting inside during Korean Literature class, I barely knew what was happening outside until someone squealed out loud. All students' heads turned toward the high windows and within seconds, several had already gone to put the blinds up all the way. It was pretty surreal; the tiniest ice flowers danced down, reaching the surface below with such lightness. Flakes melted the moment they touched the glass our foreheads were pressed against. One disappeared before my eyes like a dream, only leaving a drop that slid down in its wake. *

I tried to capture that special moment onto a picture - the burst of childish excitement and buoyant ecstasy. But the flakes were simply too small to show up clearly...and besides, our teacher had already hollered at us to get back to our seats after his own brief instant of sheer wonder. 

Below are  photos taken recently that embody the mood of the coming winter. One was taken by my friend on the day of the snowfall -  who amazingly took a picture at the very minute the sky turned sepia!

* This reminds me of the story of Bentley - the man who discovered and photographed snowflakes for the first time. From a very young age, he was greatly interested in snow. Using the microscope that his school teacher mother had given him, he attempted to take pictures of the snowflakes. One of the hardest things was capturing them onto film before they melted away. Still, in the end he succeeded in his life mission, and presented to all of humanity the microscopic beauty that had been utterly ignored before. What Bentley said about snowflakes goes well for many other things in life, I think: "No two snowflakes are alike."

Taken by Hyo Jung Ryu

It wonderfully paints the change of seasons. 

You can see snowflakes if you look closely! 

A photo taken hastily on the way out. 

Snow sprinkled on the top of the bike shed. 

Snow among the late autumn leaves

The last of the Ginkgo seeds tumbled onto the ground

An upside-down leaf-chandelier?

How Leaves Change in Fall - Sookmyung Girls' High School

Autumn seems to be passing by really quickly. The leaves are changing their colors in a flash and the ground is becoming simply carpeted, if I allow a little exaggeration. 

Every day adds a different shade to the foliage, so I always try to give the trees I pass all the time more than a few glances. I don't want to miss a single "step" in their transformation; it would be such a shame. That brings me to a question that really filled my mind when I was little: Why do leaves change color?

Only just a while ago, the leaves still retained their green tints

Many of us think that leaves change due to the falling temperatures. Although not entirely incorrect - temperature does alter the intensity of the hues - it's only one of the many factors that contribute to their transition.

In middle-school biology, we learn that the green color in leaves is caused by the presence of chlorophyll. This pigment converts light energy that it absorbs into chemical energy so that it can be used in changing carbon dioxide and water into oxygen and carbohydrates like starch. The jade/grass/lime color is present throughout most of the year because the leaf organ acts as the "food factories" for the plant. Other pigments are present, but the chlorophyll blocks them out because it is constantly replenished. 

Now, an entirely different harmony of colors plays

When the seasons change, however, and the length of day alters with the temperature, a layer of special cells forms at the base of each leaf. They are cork cells, a tissue found in many vascular plants. This layer blocks the movement of fluids into and out of the leaf, so naturally, water and mineral intake is reduced. Chlorophyll begins to decrease as well.

As the green shade begins to weaken, other pigments are unmasked. The yellow pigments (xanthophylls), orange pigments (carotenoids) and red and purple pigments (anthocyanins) burst into the blue-green.

Perhaps the mesmerizing beauty of the shades make autumn seem shorter than it actually is. While a brief (as it seems to me) firework of colorful splashes is taking place, the layer of cork cells continues to develop and steadily weaken the connections between other cells. Eventually, the tissues are severed, and we see the fallen foliage at the bases of trees, withering away, adding a new sound - "crunch crunch" - to the season.