Thursday, December 23, 2010

Passive Heating And Cooling


Passive systems can be defined as those, in which the control of flow of thermal energy is by natural means.
The following 5 types of passive heating and cooling systems are common.
1. Direct gain
2. Thermal storage wall
3. Solar greenhouse
4. Roof pond
5. Convection loop

1. Direct gain
A large exposure of vertical glass window in the south admits the suns rays allowing it to strike the masonry floor and wall, which acts as thermal storage. The thermal energy stored is distributed in the room by convection and conduction. Temperature swings up to 10 degree Celsius can be achieved.
The system can be controlled:
External reflectors increase solar gain,
Movable insulated shutters used at night reduce heat loss,
External blinds and overhangs can reduce overheating,
The vertical glazing allows lower winter sun to strike at right angles whilst reflecting the high glancing summer rays.

Heating Mechanism
Short wave radiation from sun enters the room and strike the thermal mass. Heat is distributed from this mass by long wave radiation (whish cannot pass through glass), by convection of room over the slab, and by conduction (if one sits or stands on the thermal mass). Movable insulation keeps the heat in at night.

2. Thermal storage wall:
In this method solar radiation is collected in or blocked outside a living space by creating a thermally massive wall between it and the sun. Heat is stored in this thermal mass and is redistributed to the living space by re-radiation through the back of the wall and or by convection of cool room air passing the warm face of the mass by natural thermosyphoning. This thermosyphoning effect is created on the sunny face of the wall by placing a glazed screen about 50 mm away from the face wall, punching holes in the top and buttom of the wall and letting the room air naturally thermosyphon and become warm. Such walls are called trombe walls. When horizontally stacked drums of water are used as thermal mass it is called drum wall, if vertical drums used it is called a water wall.

Heating Mechanism
Short radiation from the sun strikes the thermal mass. During a winter day cool room air cycles up between the glass and the warmed mass, re-entering the room space at the top. During a winter night, heat that has diffused through the wall is radiated into the living space while room air is also heated by convection.
Control of this heating mode is done by:
The size of thermal mass is optimized to ensure a sufficient time lag before re-radiation occurs.
External blinds and overhangs reduce summer overheating.
Manually operated dampers can control the direction and volume of the thermosyphoning air.

3. Solar greenhouse
This heating mode is development of trombe wall. The only difference is that the space between the wall and glass id widened to make a green house. The thermal movement as well as control is similar. The greenhouse also serves as usable living space and provides opportunity for growth of vegetation. The solar greenhouse can be made with glazed wall between greenhouse and living space or a massive wall between the two.

4. Roof Pond
This heating mode transfers the thermal storage to the roof, consists of plastic bags of water that are supported on a steel deck roof or RCC construction on the roof to form a pond with proper water treatment avoiding leakage.
Control is done by positioning movable insulating shutters.
The shutters are left open during day and closed during night in summer. In winters the vice-versa.

6. Convection Loop
In this system an angular solar collector heats a transport fluid and by a thermosyphoning loop allows it to rise to a thermal store located above the collector.
Control is affected first by the correct sizing of the thermal store and collector and second by the use of dampers to regulate the direction and volume of air flow.

Friday, December 17, 2010

Features of Rock Outcrops

The distinctly visible features of the rock outcrops are known as planner features of the rock outcrops.Planner
features are important in the study of the structural features of rocks. There are different planner features,
which can be observed in rock outcrops:

Bedding Plane

         The layer which is easily distinguished on the basis of variation in colour, composition and grain
size is known as bed. The plane of this bed or strata is known as bedding plane. It is of fundamental significance
in the study of structural features of sedimentary rocks. The different beds are distinguished from each other by the
difference in mineral composition, variation in grain size or texture, difference in colour and variation in thickness etc.

Foliation Plane

          The segregation of minerals into layers or bands of contrasting mineralogical composition is known as
foliation. The plane of these different bands in metamorphic rocks is known as foliation plane. Foliation plane
is generally formed by dynamo-thermal metamorphism of coarse-grained igneous and sedimentary rocks at progressive
stages of the process. 


          The ruptured surfaces present as cracks in rocks are known as joints. These are the divisional planes
or fractures, which divide rocks into parts or blocks without transverse movement of the blocks. There may or
may not be small movement in the blocks perpendicular to the fracture surface.


          Folds are wavy undulations developed in the surface of the rocks as a result of stresses to which
these rocks have been subjected from time to time. Folds may develop in any type of rock and may be of any shape,
from simple symmetrical up warping or down warping to complex geometrical patterns. The ultimate shape and extent
of folds depend upon a number of factors like the nature, magnitude, direction and duration of forces involved in
the process and the nature of the rocks subjected to such a process.


        An unconformity is defined as a surface of erosion or non depositing occurring within a sequence of rocks.
It indicates a gap or interval of time in the geological history of the area during which the normal process of
deposition was interrupted. It is a structural feature in the sense that rock formations lying above and below it
generally represent different conditions under which they have been formed. Unconformities are recognized in the
field as follows:

·        Visual inspection of the angular relation between the sequences.

·        Presence of Basal Conglomerate.

·        Availability of the residual soil within the sequence of rocks.

·        Exposure of the erosional surface.

·        Contrasting behavior of the rocks from a particular surface.

·        Variation or gap in the geological age of the rocks of the sequence.


          A fault is a planar discontinuity between blocks of rocks that have been displaced past one another in
 a direction parallel to the discontinuity. The faults are distinguished on the basis of following factors:

a) The apparent movement of the disrupted blocks along the fault plane.

b) The relation of the fault attitude (dip and strike) to the attitudes of the

   displaced beds.

c) The direction of the slip.


             Football, also called “soccer” is the most popular sport on the planet. From Brasilia to Tokyo, London to Canberra , Ottawa to Kathmandu there is no place on earth that has not been graced by the game they call “the beautiful game” . It is played by everyone and transcends all boundaries, borders, languages, religion,gender, colour and race.
           Two teams of 11 players(excluding substitutes) each take part in a football match.
They attempt to send a round ball into their opponent’s goal. A successful attempt is called “scoring a goal”. The team with the most number of goal within the 90 minutes of playing time(divided into two halves of 45 minutes with some additional time called “injury or added time”) wins the match. Players use their feet, head or any other part of the body except for the hands and arms to propel or control the ball. One player from each side, the goalkeeper, may handle the ball, but only in a restricted area around the goal called the “D-box”. There is considerable physical contact as opposing players contest possession of the ball.
         Football as it is played today began in England in the mid 1800’s.The governing body for world football, Fedration Internationale de Football(FIFA) was established in 1904. FIFA stages the biggest event in world football i.e. Football World Cup every four years which it started in 1930.Spain are the current World Cup Champions having won the FIFA World Cup 2010 which was held in South Africa.

Thursday, December 16, 2010


        Nepal often called the Himalayan country, is situated on the southern slope of the central Himalayas. It is located  between 260 22’ N to 300 27’N  latitude and  800 4’E to 880 12’E  longitude.It is a land of great contrast.The elevation here ranges from 90 to 8848 meters(Which is the top of Mount Everest),the average length of the country being 995km east to west and average breadth of about 123km north to south.
               The country is located between the two most populous countries in the world, India in the east, south, west and Tibet region of People’s Republic of China in the north. Nepal is a landlocked country with an area of147181sq km. The northern range (Himalayas) is covered with snow throughout most of the year where the highest peak of the world, Mount Everest (8848 meters high) is located. The middle range (hills) consists of   picturesque hills, valleys and lakes. The southern range (Terai) is the plain of alluvial soil and consists of dense forest areas and large agricultural land as well as various industries.

            The temperature and rainfall differ from place to place. Generally, it is cooler in the north and temperature increases as we move to the south of the country.In the vast geographic diversity and varied climatic conditions 23.1 million people of more than 60 caste/ethnic groups reside. Nepal presents an example of  being united irrespective of  its diversities throughout its history.

           The official language of Nepal is Nepali although more than 100 languages(including dialects) are spoken within its boundaries.Kathmandu is the capital city of the country. The Kathmandu Valley comprises of the historical cities of Bhaktapur, Patan And Kathmandu.

Some of the most famous places of interest and activities in Nepal are the three  Durbar Squares inside the Kathmandu Valley,Annapurna Trek route,the Mt.Everest trek and mountain flights,Lumbini-the birthplace of Lord Buddha,Jungle safari in Chitwan National Park,adventure sports including bungee diving,para-gliding,rafting,etc. in Pokhara,Bhotekoshi,Trusuli,etc.And there are lots more.

Planet Viewing

Mercury symbolMercury
The solar system's smallest planet flits back and forth from morning sky to evening sky several times a year. It never strays far from the Sun in our sky, so it's tough to find in the glare. From the northern hemisphere, it is visible in the morning sky this year in March and April, July, and early November. The late-year appearance is the best, because the planet will stand highest above the horizon. In the evening, Mercury is best seen in January, May, late August through September, and mid-December. The May appearance is best.
Venus symbolVenus
Venus, the dazzling morning or evening star, outshines all the other stars and planets in the night sky. It begins the year in the morning sky, low in the east shortly before sunrise. It will disappear from view in early May. In mid-July Venus will reappear in the evening sky, where it stay for the rest of the year.
Mars symbolMars
Mars begins the year as a brilliant orange star high in the east at sunset. As the year progresses, it will grow fainter, shining only about five percent as bright in late summer as in January. It will disappear in the Sun's glare by around mid-October.
Jupiter symbolJupiter
The largest planet in our solar system is a commanding presence in the night sky for much of the year. It looks like an intensely bright cream-colored star, shining brighter than anything else in the night sky except the Moon and Venus. It climbs into view in the pre-dawn sky in January. It rises earlier as the months go by, and moves into the evening sky in spring. Jupiter is at opposition in early July, when it appears brightest for the year and remains visible all night. Late in the year it is visible only in the evening sky, dropping lower each night.
Saturn symbolSaturn
Saturn looks like a bright golden star. It spends the year in Leo, the lion, and for much of the year is close to Leo's "heart," the bright star Regulus. Saturn is at its best in late February, when it's closest to Earth. It disappears behind the Sun in July and August, then returns to view in the morning sky.
Uranus symbolUranus
Although it's the third-largest planet in the solar system, it's so far from the Sun that you need binoculars to see it. It spends the year in the constellation Aquarius. It stages its best appearance in September.
Uranus symbolNeptune
The fourth-largest planet in the solar system is so far away that you need a telescope to find it. Neptune is in the constellation Capricornus, and stages its best appearance in August.


The science of sound- Acoustics- can be broadly divided into two major areas:
  1. The handling of wanted sound, i.e. creating the most favorable conditions for listening to a sound we want to hear: room acoustics
  2. The handling of unwanted sound, i.e. the control of noise
Sound incident on the surface of a solid body (e.g. wall) is partly reflected, partly absorbed (converted into heat) and partly transmitted to air on the opposite side.
If source I = 1, r + a + t = 1


The complex pattern of interreflected sound, usually referred as reverberant component which if managed can result in better acoustics.

From the point of view of the building which is to be designed, it is useful to distinguish:
a)      External noises
b)      Internal noises
Against external noises following means of protection are available:
  1. Distance
  2. Avoiding zones of directional sound
  3. Screening
  4. Planning: using non noise-sensitive parts of the building as barriers
  5. Positioning of openings away from noise source
  6. Noise insulating building envelope
Against noises generated within the buildings following measures can be taken:
  1. Reduction at source
  2. Enclosing and isolating the source, or use absorbent materials
  3. Planning: separating noisy spaces from quiet ones, placing indifferent areas in between
  4. Placing noisy equipment in the basement
  5. Reduce impact noises by covering surfaces with resilient materials
  6. Reduce noises in the space where it is generated by absorbent surfaces
  7. Reduce airborne sound transmission by airtight and noise insulating construction
  8. Reduce structure borne sound transmission by discontinuity