Mars Orbiter sends pictures of dust storm activities on the Red Planet

The latest picture taken by ISRO's Mars Orbiter shows the complete Red Planet in the frame. (Photo: AP)
ARTICLE IN DECCAN CHRONICLE 

Bangalore: India's Mars orbiter has sent a picture of regional dust storm activities over the northern hemisphere of the Red Planet, ISRO said on Monday.

"Regional dust storm activities over northern hemisphere of Mars - captured by Mars Color Camera on-board Mars Orbiter Mission (MOM)", Bangalore-headquartered Indian Space Research Organisation (ISRO) said on its official Facebook page with a picture.

It said the image was taken from an altitude of 74,500 km from the surface of Mars.

MOM spacecraft had sent its first images of the planet on Thursday, a day after creating history by becoming the only such endeavour so far to have met with success on the maiden attempt.

MOM aims to study the Martian surface and mineral composition and scan its atmosphere for methane, an indicator of life.

The spacecraft is equipped with five instruments, including a sensor to track methane or marsh gas, a colour camera and a thermal-imaging spectrometer to map the surface and mineral wealth of the planet.

The Rs. 450-crore MOM is the cheapest inter-planetary mission. India is the first country to reach Mars in the very first attempt. European, American and Russian probes have managed to orbit or land on the planet, but after several attempts.

The orbiter will keep moving in an elliptical path for at least six months with its instruments sending their gleanings back home.

The spacecraft was launched on its nine-month-long odyssey on a homegrown PSLV rocket from Sriharikota in Andhra Pradesh on November 5, last year. It had escaped the Earth's gravitational field on December 1 and was placed in the Martian orbit on September 24.

PRECAST PREFAB BUILDING COMPONENTS

Prefabrication is a technique for faster and environmental friendly in building construction. Prefabrication is efficient in terms of cost, time, quality and environmentally friendly way of building with optimum use of materials, recycling of waste products, less noise and dust etc. The jointing connections between precast panels play a vital role in determining the strength, stability, loading distribution and constructibility of a structure. This paper deals with different connection and joints in precast concrete construction dealt by various researchers and construction agencies, and also the new development that are taking place in our country for the light weight large prefab wall and roof panels. .

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Delhi Metro ranked 2nd among 18 international metro systems

Delhi Metro has been ranked second among 18 international Metro systems in terms of overall customer satisfaction in an online customer survey.

According to a DMRC official, in the survey conducted among the commuters of those Metro systems by Global Metro Benchmarking Groups 'NOVA' and 'CoMET', Delhi Metro along with London DLR and Bangkok were the best three performers in the 'Net Promoters Score' (NPS) category.

Under this category the survey analysed the likelihood of customers recommending the service to others on the basis of their satisfaction. More than 41,000 respondents gave their feedback worldwide in this survey conducted online through the websites and social media links of 18 major Metros of the world from April 28th to May 25th earlier this year.

The Metro systems that participated in this survey apart from Delhi Metro were Hong Kong MTR, London Underground, Metro De Madrid, Paris RATP, Metro De Sandiago, Singapore  MRT, Barcelona TMB, Brussels STIB, Bangkok BMCL, London DLR, Istanbul Ulasim, Kualalumpur Rapid PL, Metropolitano De Lisboa, Montreal STM, Newcastle Nexus, Metro Rio and Toronto TTC.

The NPS is calculated by the percentage of promoters minus the percentage of detractors (P-D = NPS). When asked to list out the three top priority areas, the respondents from Delhi along with 17 other Metros listed as 'availability' as the most important requirement. Only New Castle and Hong Kong selected 'Reliability' as their most important area.

Courtesy  - http://www.deccanchronicle.com/140928/nation-current-affairs/article/delhi-metro-ranked-2nd-among-18-international-metro-systems

Floating Foundation

ROLE OF SOIL’S EFFECTIVE STRESS IN THE FIELD OF CONSTRUCTION

(FLOATING FOUNDATION)

Abstract

Effective stresses at a point in soil mass are equal to the total stress at that point minus the pore water pressure at the location. Certain aspects of the engineering behavior of soil especially compression and shear strength are the functions of effective stress.

The concept is based on the fact that different depths below the ground surface the soil is subjected to different overburden pressures and therefore over a period of time it achieves different state of stresses.

Effective stress is based on *Depth *Shift of water table *Shift in ground surface *Permeability * Void ratio *Seepage *Compressibility.

Compressibility- a function of stress history

 Compressibility is defined as the volumetric strain that a soil undergoes on account of rearrangement of particles that is necessary to withstand the higher imposed stresses. When soil becomes denser the compressibility decreases and effective stress increases. When a soil is subjected to effective stress for the first time in its history exhibit greater compressibility than when it has in its past been subjected to effective stresses but then has been relieved of effective stresses. Soil are not elastic in their behavior once compressed do not spring back to their loose state upon being unloaded and also that upon reloading they do not compress as much as soil that have never been loaded before.

Floating Foundation

A floating foundation is defined as a foundation in which the weight of building is approximately equal to the full weight of soil and water removed from the site of the building. The principle of foundation is an exact balance of weight removed against weight imposed & the result is the zero
settlement of the building. This type of floating foundation is used in two main cases.

Type.1: Shear failure of the soil will not occur under the building load but the settlements and particularly differential settlements will be too large and will constitute failure of structure.

Type.2:  Shear strength of the soil is low that rupture of soil would occur if the building were to be founded at ground level.

The settlement problem can be solved by solving the problems like Excavation, Dewatering, Critical depth & Bottom heave.

Conclusion

Thus settlement problem of buildings is solved by using floating foundation and there is no risk of failure.

RISK MANAGEMENT IN CONSTRUCTION INDUSTRY

A study conducted by Infrastructure & Project Monitoring Division of Ministry of Statistics and Programme Implementation reports that out of 860 central sector projects (which are of the order of more than Rs.204.2 million) costing around Rs.3432 trillion and average project duration of 6 to 7 years, about 35% are behind schedule and the delay ranges from 1 to 195 months. Time and cost overruns are a result of delays in project execution. Some of the reasons advanced for these delays and subsequent overruns in time are inclement weather, shortage in labour and material supply, sub-contractors, changes after contract execution has commenced, poor site management and government policies. The delay in a project is also due to the poorly drafted contract clauses. Identification of the contract clauses that affect the schedule of the construction project was which taken up by CPWD has been carried out in this study.

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