Category Archives: Engineering

Multiple linear regression analysis with constraints

Here is how to do it:
Suppose the linear model is of the form y=b1x1+b2x2+b3x3,

subject to b1+b2+b3=1.

We have to do is simply re-express b3 as b3=1−b1−b2,
which is to say you are trying to build a model of the form
y=x3+b1*x1+b2*x2+(1-b1-b2)*x3
y-x3=b1*(x1−x3)+b2*(x2−x3).

So create new variables y`=y-x3, x1`=x1−x3, and x2`=x2−x3, and perform the normal linear regression using these transformed variables as the independent variables.

Note that: In excel there is build in function called ‘solver’ which appears that it can be used by maximizing R^2 value and setting the constraints b1+b2+b3=1, but this wont work. The solver is good for solving ‘linear programming’ and not regression type of questions.

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Radius of earth (classical trignometry)

Question: Suppose that, while lying on a beach near the equator watching the sun set over a calm ocean, you start a stopwatch just as the top of the sun disappears. You then stand, elevating your eyes by a height H=1.7m, and stop the watch when the top of the sun again disappears. If the elapsed time is t=11.1 secs, what is the radius r of the earth?

Solution
One day=24hrs=86400sec

The earht rotate 2*pi() in one day=2*pi=6.2832 radians

angle traversed in 11.1sec=0.000807215 radians

observation height=1.7m

R=(h*cosX)/(1-cosX)=5.22E+06

earthRadius
Download calculation file

A thought on remaining happy

being happy is easy. Trying to know why we are happy leads us to vicious circle. We will find one reason that will explain why we are happy. But the question arises again why that reason makes us happy and so on.

Hydrological stations of Nepal

Here is list of hydrological station of Nepal installed by department of hydrology and meterology. The location of these places can be seen by downloading this google earth file “hydrologicalStationOfNepal.kmz”.

stations.jpg

The data listed below can be downloaded as excel file here.

SN Station No. Name of the River Location Name Latitude Longitude Elevation m Drainage Area sq. km Start of Record End of Record
1 120 Chamelia River Karkale Gaon 29 40 20 80 33 30 724 1150 01/01/65
2 169 Surnaya Gad Gujar Gaon 29 31 0 80 35 0 1275
3 170 Sumagad River Patan near Baitadi 29 27 30 80 33 10 1110 188 23/05/69
4 220 Tila Nala Nagma 29 19 0 81 55 0 1935 1870 19/03/64
5 225 Sinja Khola Diware 29 19 0 81 55 0 1943 824 17/03/64
6 240 Kamali River Asara Ghat 28 57 10 81 26 30 629 19260 01/01/61
7 250 Karnali River Benighat 28 57 40 81 7 10 320 21240 01/02/63
8 260 Seti River Banga Near Bel Gaon 28 57 40 81 8 40 328 7460 06/02/63
9 262 Thuli Gad Khanayatal Near Bel Gaon 28 56 10 80 58 0 314 896 17/06/65
10 265 Thulo Bheri River Rimna 28 42 30 82 17 30 550 6720 18/06/72
11 270 Bheri River Jamii 28 45 20 81 21 0 246 12290 23/01/63
12 280 Kamali River Chisa Pani 28 38 40 81 17 30 191 42890 01/01/62
13 286 Sarada Khola Daredhunga 28 17 58 82 1 30 579 26299
14 290 Babai River bargadha 28 25 20 81 22 10 192 3000 16/07/66
15 330 Mari Khola Naya Gaon 28 4 20 82 48 0 536 1980 01/01/64
16 339.5 Jhimruk Khola Tigra Gaon 28 3 0 82 49 40 762 683 22/05/71
17 340 Jhrimruk Khola Kalimati Ghat 28 2 10 82 53 0 692 696 01/01/65 21/05/71
18 350 Rapti River Bagasoti Gaon 27 54 0 82 51 0 381 3380 08/05/75
19 360 Rapti River Jalkundi 27 56 50 82 13 30 218 5150 08/04/64
20 375 Rapti River Kusum 28 0 27 82 5 35 235 21/12/2002
21 390 Tinau Khola Butwal 27 42 10 83 27 50 184 554 09/12/63
22 395 Banganga River Bangachia 27 49 50 83 6 40 571 347 01/01/66 omitted
23 404.7 Myagdi Khola Mangia Ghat 28 21 30 83 32 0 914 1112 19/05/75
24 410 Kali Gandaki Seti Beni 28 0 30 83 36 10 546 6630 21/02/64
25 415 Andhi Khola Duinrichaur, Andhimuhan 27 58 20 83 35 20 543 476 06/04/64
26 417 Badigad Khola Rudrabeni, Gulmi 27 58 20 83 28 10 731 1990 24/05/67
27 419 Kali Gandaki Angsing 27 53 24 83 48 0 351.05 13/04/1989
28 420 Kali Gandaki Kota Gaon 27 45 0 84 20 50 198 11400 15/04/64
29 428 Mardi Khola Lahachok 28 18 30 84 20 50 915 160 07/06/70
30 430 Seli River Phoolbari 28 14 0 84 0 0 830 582 01/01/64 omitted
31 438 Madi Khola Shisa Ghat 28 6 0 84 14 0 457 858 08/02/73
32 439 Marsandi River Bimalnagar 27 57 0 84 25 48 354 31/03/87
33 439.3 Khudi Kliola Kliudi Bazar 28 17 15 84 21 45 990 151 04/07/81
34 439.7 Marsyangdi River Bimal Nagar 27 57 0 84 25 48 354 3774 31/03/87
35 439.8 Marsyangdi River Gopling Ghat 27 55 35 84 29 42 320 3850 01/06/73 24/06/88
36 440 Chepe Khola Garani Besi 28 3 41 84 29 23 442 308 20/11/63
37 445 Burhi Gandaki Aru Ghat 28 2 37 84 48 59 485 4270 28/11/63
38 446 Phalanku Khola Betrawati 27 58 25 85 11 15 630 24/2/69
39 446.8 Phalandu Khola Betrawati 27 58 25 85 11 15 630 162 24/04/69
40 447 Trisuli River Betrawati 27 58 8 85 11 0 600 4110 01/04/67
41 448 Tadi Kliola Tadi Pool, Belkot 27 51 35 85 8 18 475 653 14/06/68
42 450 Narayani River Narayan Ghat 27 42 30 84 25 50 180 31100 10/02/62
43 460 Rapli River Rajaiya 27 26 30 84 58 15 332 579 01/01/63
44 465 Manahari River Manahari 27 33 0 84 48 10 305 427 13/06/63
45 470 Lotliar Kliola Lothar 27 35 40 84 43 0 336 169 30/11/63
46 475 Kliageri Kliola Tikauli 27 37 20 84 30 0 195 118 01/08/64 omitted
47 480 Kair Kliola Jurrpani 27 40 40 84 33 40 241 80 01/01/64 omitted
48 485 Buri Rapti Chitrasari 27 37 0 84 29 15 189 184 01/01/64 20/07/88
49 505 Bagamati River Sundarijal 27 6 30 85 27 10 1600 17 07/12/62
50 507 Nagmati River Sundarijal 27 46 20 85 26 10 1660 13 01/11/63 27/08/92
51 510 Sialmati Shyamdado 27 46 10 85 25 10 1660 3 01/11/63 28/08/92
52 530 Bagmati River Gaurighat 27 42 30 85 21 0 1300 68 15/11/64
53 536.2 Bislmumati Kliola Budhanilkantha 27 46 49 85 21 32 1454 4 27/05/68 27/08/92
54 540 Nakliu Khola Tika Bhairab 27 34 30 85 18 50 1400 43 23/11/62 18/04/88
55 550 Bagmati River Chovar 27 39 40 85 17 50 1280 585 08/07/62 omitted
56 560 Thado Khola Darkot- Markhu 27 36 20 85 9 0 1830 14 01/01/64 omitted
57 565 Kulekhani Khola Lamichaur 27 36 13 85 9 39 1514 122 17/07/75 09/12/78
58 570 Kulekhani Khola Kulekhani 27 35 10 85 9 30 1480 126 01/12/62 15/11/77
59 589 Bagamati River Pandhera Dovan 27 6 20 85 28 30 180 2700 28/01/79
60 590 Bagmati River Kamiaiya, Mangalpur 27 6 20 85 28 30 177 2720 21/06/64 17/10/84
61 600 Arun River Uwa Goan 27 36 0 87 20 6 1294 26608
62 600.1 Arun River Uwa Gaon 27 36 0 87 20 6 1294 26750 11/05/72
63 602 Sabhaya Khola Tumlingtar 27 18 20 87 13 15 305 375 02/01/74
64 604 Arun River Turkeghat 27 20 0 87 11 30 414 23/05/75
65 604.5 Arun River Turkeghat 27 20 0 87 11 30 414 28200 23/05/75
66 606 Arun River Simie 26 55 30 87 9 30 152 30380
67 610 Bhote Koshi Barabise 27 47 10 85 53 20 840 2410 17/02/65
68 620 Balaphi Khola Jalbire 27 48 20 85 46 10 793 629 25/12/63
69 625 Sunkoshi River Dolalghat 28 38 30 85 43 0
70 627 Melanchi Khola Helambu 28 2 30 85 32 0 2134
71 627.5 Melamchi Khola Helambu 28 2 30 85 32 0 2134 84
72 629 Indrawati River Dolalghat 27 38 20 85 42 30 26559
73 630 Sun Koshi Pachuar Ghat 27 33 30 85 45 10 589 4920 26/03/64
74 640 Roshi Khola Panauti 27 34 50 85 30 50 1480 87 17/10/63
75 647 Tama Koshi Busti 27 38 5 86 5 12 849 2753 14/01/70
76 650 Khimti Khoal Rasnalu Village 27 34 30 86 11 50 1520 313 06/04/64
77 652 Sun Koshi Khurkot 27 20 0 86 0 0 455 10000 01/07/67
78 660 Likhu Kliola Sangutar 27 20 10 86 13 10 543 823 24/03/64
79 665 Sunkoshi River Tokselghat 27 10 30 86 22 0 20/02/1986
80 668.4 Taktor Kliola Beni 27 31 45 86 33 30 2350 87 /76
81 670 Dudli Koslii Rabuwa Bazar 27 16 0 86 39 50 460 4100 10/03/64
82 680 Sun Koslii Hampuachuwar 26 52 30 86 49 20 200 17600 28/06/65
83 684 Tamur Majliitar 27 9 30 87 42 45 533 4076
84 690 Tamur River Mulghat 26 55 50 87 19 45 276 5640 11/03/65
85 695 Sapta Koshi Chatara-Kothu 26 52 0 87 9 30 140 54100 01/01/77
86 728 Mai Khola Rajdwil 26 52 45 87 55 45 609 377 01/01/83
87 730 Puwa Kliola Sajbote Ham 26 55 0 87 54 40 802 107 18/01/65
88 738 Maikhola Rajdwali 26 52 45 87 55 45 609 30317
89 770 Kankai Mai River Chepti 26 43 50 87 52 30 140 1150 21/02/64 29/08/74
90 795 Kankai Mai Khola Mainachuli 26 41 12 87 52 44 125 1148 01/05/71

Drinking water test kits

USD1=NPR 80

Followin test kit are available in ENPHO Nepal. The cost and name of test are compiled here so that it can be viwed easily in single page.

Ammonia Test Kit

The ENPHO Ammonia Test Kit is especially designed for testing the concentration of ammonia in water.

Range

0 – 3ppm

Test Method

Colorimetric

Testing Time

Within 5 minutes

Reagents

Ammonia Reagent 1 & Ammonia Reagent 2 (Can be refilled after finished)

Number of Test

100

Price

NRs. 1690.00 (13% VAT Extra)

ENPHO Arsenic Field Test Kit

ENPHO has developed a semi-quantitative low cost field test kit for testing untreated ground water, like tube-well. The salient features of the kit are easy to test, portable and rapid. Once the reagents are finished they can be refilled. If the concentration of arsenic in the water is higher than 150ppb it is better to dilute the sample with distilled water, for better result.

Range

10ppb – 500ppb

Test Method

Colorimetric

Testing Time

within 10 minutes

Regents

Tablet 1,Tablet 2, Mercuric Bromide paper and Reagent 1

Number of Test

50

Price

Rs.5700.00 (13% VAT Extra)

Chloride Test kit

The ENPHO chloride Test Kit is especially designed for on field testing of chloride in water.

Range

Minimum 3.92mg/L

Test Method

Titrimetric

Testing Time

Within 5 minutes

Reagents

Choride Reagent 1 & Chloride Reagent 2 (can be refilled after finished)

Number of Test

100

Price

NRs. 1440.00 (13% VAT extra)

Dissolved Oxygen Test kit:

The ENPHO dissolve Oxygen Test Kit is especially designed for testing dissolved oxygen in water. This test Kit can be used for testing water from all sources except wastewater. The salient features of this Kit are portability, rapid result, simple method and low cost. Each test kit contains reagents to test 100 water samples. This kit can test the minimum of 0.8mg/l.

Range

Minimum 0.8mg/L

Test Method

Titrimetric

Testing Time

within 10 minutes

Regents

Dissolved Oxygen Reagent 1,
Dissolved Oxygen Reagent 2, Dissolved Oxygen Reagent 3, Dissolved Oxygen Reagent 4, Dissolved Oxygen Reagent 5

Number of Test

100

Price

NRs. 2510.00 (13% VAT Extra)


Coliform Presence/Absence Test kit

Coliform presence/absence test kit is used to detect the bacterial contamination of drinking water. It shows Whether the bacteria is present or absent.

Range

Presence or Absence

Test Method

H2S Method

Testing Time

Up to 48 hours

Number of Test

1

Price

Rs.45.00 (13% VAT extra)

Free Residual Chlorine Test Kit

ENPHO has introduced portable Free residual chlorine test kit to test the chlorine content of chlorinated water as well as water from Drinking water supply system.

Range

0.2 – 1ppm

Test Method

Colorimetric

Testing Time

30 sec.

Number of Test

400

Price

NRs. 140.00 (13% VAT Extra)

Iron Test Kit

The ENPHO Iron test Kit is designed for testing Iron concentration in water.

Range

0 – 10ppm

Test Method

Colorimetric

Testing Time

Within 10 minutes

Reagents

Iron Reagent 1, Iron Reagent 2, Iron Reagent (can be refilled after finished)

Number of Test

100

Price

NRs. 1800.00 (13% VAT Extra)


Hardness Test Kit

The ENPHO Hardness Test Kit is designed for testing the hardness of water in the field.

Range

Minimum 8 mg/L

Test Method

Titrimetric

Testing Time

Within 10 minutes

Reagents

Hardness Reagent 1, Hardness Reagent 2, and Hardness Reagent 3 (can be refilled after finished)

Price

NRs. 1520.00 (13% VAT Extra)

Nitrate Test Kit

The ENPHO Nitrate test Kit is designed for testing Nitrate concentration in drinking water. For testing nitrate the water sample has to be digested which is an easy process.

Range

0 – 100ppm

Test Method

Colorimetric

Testing Time

Within 20 minutes

Reagents

Nitrate Reagent 1 and Nitrate Reagent 2 (Can be refilled after finished)

Number of Test

100

Price

NRs.1880.00 (13% VAT Extra)

Phosphate Test Kit

The ENPHO Phosphate test Kit tests the level of Phosphate concentration in drinking water.

Range

0 – 1ppm

Test Method

Colorimetric

Testing Time

Within 5 minutes

Reagents

Phosphate Reagent 1,Phosphate Reagent 2

Number of Test

100

Price

NRs. 1620.00 (13% VAT Extra)

ENPHO Water Field Test Kit

ENPHO Water field test kit is especially designed for testing drinking water and water from fresh water bodies. This kit can test 10 parameters viz. pH, Temperature, Chloride, Hardness, Iron, Ammonia, Nitrate, Phosphate, Free Residual Chlorine and Coliform. This kit can test 100 water samples for each parameter except Coliform. (Only 10 Coliform P/A vials are provided). This kit is designed only for testing drinking water. If drinking water is very turbid it should be filtered before testing with this kit.

Price:

NRs. 14000.00 (13% VAT extra)