Friday, September 19, 2014

Common Light Levels

Common Light Levels Outdoor

Common light levels outdoor at day and night can be found in the table below:
Condition Illumination
(ftcd) (lux)
Sunlight 10,000 107,527
Full Daylight 1,000 10,752
Overcast Day 100 1,075
Very Dark Day 10 107
Twilight 1 10.8
Deep Twilight .1 1.08
Full Moon .01 .108
Quarter Moon .001 .0108
Starlight .0001 .0011
Overcast Night .00001 .0001

Common and Recommended Light Levels Indoor

The outdoor light level is approximately 10,000 lux on a clear day. In the building, in the area closest to windows, the light level may be reduced to approximately 1,000 lux. In the middle area its may be as low as 25 - 50 lux. Additional lighting equipment is often necessary to compensate the low levels.
Earlier it was common with light levels in the range 100 - 300 lux for normal activities. Today the light level is more common in the range 500 - 1000 lux - depending on activity. For precision and detailed works, the light level may even approach 1500 - 2000 lux.
The table below is a guidance for recommended light level in different work spaces:
Activity Illumination
(lux, lumen/m2)
Public areas with dark surroundings 20 - 50
Simple orientation for short visits 50 - 100
Working areas where visual tasks are only occasionally performed 100 - 150
Warehouses, Homes, Theaters, Archives 150
Easy Office Work, Classes 250
Normal Office Work, PC Work, Study Library, Groceries, Show Rooms, Laboratories 500
Supermarkets, Mechanical Workshops, Office Landscapes 750
Normal Drawing Work, Detailed Mechanical Workshops, Operation Theatres 1,000
Detailed Drawing Work, Very Detailed Mechanical Works 1500 - 2000
Performance of visual tasks of low contrast  and very small size for prolonged periods of time 2000 - 5000
Performance of very prolonged and exacting visual tasks  5000 - 10000
Performance of very special visual tasks of extremely low contrast and small size 10000 - 20000

 

Calculating Illumination

Illumination can be calculated as
I = Ll Cu LLF / Al       (1)
where
I = illumination (lux, lumen/m2)
Ll = lumens per lamp (lumen)
Cu = coefficient of utilization
LLF = light loss factor
Al = area per lamp (m2)

Example - Illumination

10 incandencent lamps of 500 W (10600 lumens per lamp) are used in an area of 50 m2. With Cu = 0.6 and LLF = 0.8 illumination can be calculated as
I = 10 (10600 lumens) (0.6) (0.8) / (50 m2)
  = 1018 lux

Thursday, September 18, 2014

PSUs considering GATE scores for entry level Engineer positions

Public Sector undertaking (PSU) is a Government owned corporation or a company in which Central or State Government have more than 51% share. Basically these Government companies run like private companies and share profits to Government. A career with PSU requires, a strong and in-depth technical knowledge and understanding of core engineering Principals. GATE is one such exam, where ones technical and general aptitude is tested. Today, more than 2000 jobs are available for a fresh graduate in engineering in major PSUs in India. The list includes IOCL BHEL, NTPC, BPCL, CEL Power Grid and likes.

All these Public sector companies recruit Engineer Trainee (ET) based on the GATE scores. Initially they would shortlist candidates based on GATE scores and then the process is followed by GD and Interview for assessment of different facets of knowledge.


Logos Date of starting Number of vacancies Streams Eligible CTC Links
POWER
Power grid
NA NA EE NA Click here for more details
250px-Indian_Oil_Logo.svg
IOCL
NA NA CH ,CE, CS, EE, EC, ME, IN NA Click here for more details
200px-Bharat_Petroleum_Logo.svg
BPCL
NA NA ME, EE, IN, CE, CH 10.5lakhs PA Click here for more details
CEL
CEL
NA NA EC, EE, ME NA Click here for more details
coalindia
COAL
NA NA ME, EE, GG ,IN NA Click here for more details
ONGC
ONGC
NA 745 NA NA Click here for more details

HPCL
Start of online application
December 18, 2014Last date for submission of application: February 2, 2015
NA ME, CE, EC, EE, IN, CH NA Click here to for more details
mdl-logo
MDL
Start of online application
December, 2014Last date for submission of application: January, 2015
34 ME, EE NA Click here for more details
npcc-logo
NTPC
Last date for submission of application by candidates to NPCCL: February 28, 2015 NA CE NA Link will be provided soon
!PSPCL
PAPCL
NA NA EE, ME, CE, EC, IN, CS NA Click here to for more details
!THDC
THDC
NA NA NA NA Click here to for more details

NHPC
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