Map of Nasir Khusraw's Travels (1046-1052)

View Nasir Khusraw's Travels (1046-1052) in a larger map


Adapted from the Naser-e Khosraw's Book of Travels, W. M. Thackston, Jr. New York, 1986

Nasir Khusraw's Safarname (Book of Travels) has been a classical text for Persian travel writing for the last 1000 years. Confessing that his travels are due to mid life crisis, he set out for Mecca at the age 42 after seeing a dream while in a drunk situation. In his dream, he was pointed the qibla direction (Mecca) when he asks about where the wisdom lays. Following this, he resolves to go for Hajj and rather immediately sets our for Mecca. For the next seven years, he travels through Persia, West Azerbaijan, Turkey, Syria, Cairo, Hijaz, Hafsa and Basra region. 

Mt. Defiance Hike

Mt. Defiance Hike

GPS log overlayed on Google Earth:

 

Columbia Gorge from the Starvation Ridge
 

Warren Lake
  

Trail



The Peak 4900 ft (note the landmark)

Munra Point Hike, Oregon

Munra Point hike

Beacon Rock from the Munra Point trail

Panoramic Columbia River 

Larch Mountain Backpacking - Oregon, United States

Larch Mountain Backpacking

We started on Friday around 7 pm and keep walking until the sun set around 8.10. Found a nice camping spot next to the river and setup the tents. Thanks to the tall trees and no moon, the camp site was pitch black making it a different experience. Had our dinner and went to sleep around 10.30 pm. Woke up at 4.30, had breakfast and started walking up. The weather and the trail were nice. There was snow after 3500 ft but it was okay. We reached the Sherard's point at Larch Mountain at 8.30 am. The view was worth the climb. Except Mt. Rainier, all major mountains were visible (Mt. Hood, Mt. Jefferson, Mt. St. Helens and Mt. St Adams)

Mt. Hood from the Larch Mountain Summit

Our camping ground:

Diffraction from Double Slits (Young's Double Slits)

The double slit diffraction is illustrated via the use of finite-difference time-domain (FDTD) simulation. Two sets of double slits with different widths and a single slit - for comparison - are illuminated by normally incident plane waves. When the impinging plane waves reach the slits, they are diffracted into a series of circular waves. In the case of double slits, constructive and destructive interferences create dark (null) and bright spots. Diffraction is basically the phenomenon involving the bending of waves around obstacles and the spreading out of the waves past small openings. Huygen's Principle states that every point on a wavefront acts as a source of tiny wavelets moving forward with the same speed as the wave and the wavefront is the surface tangent to these wavelets. 

Keywords:

Beugung, Difracción, Diffrazione, Kırınım, 回折, Дифракция, Diffractie, Difração, 衍射, Dyfrakcja, Diffraktion, Interferenz, Interferencia, Young's slit,

Mount St. Helens Walk-up

We started around 6.30 am after camping overnight. After walking continuously around 6 hours we reached the summit around 12.30 pm. We reached back the Marble mountain sno-park at 4.00 pm.

Mount St. Helens Walk-up

Mount Rainier and Mt. St. Helen's Crater Rim

Climbers on the crater rim.

Mt. Rainier and Spirit Lake

Smoke coming from the Mt. St. Helen's crater

Link error when changed from the debug mode to release mode (Intel MKL and Intel Visual Fortran Studio XE for Windows)

From the Intel MKL Link Line Advisor, I was given the following libraries to be linked:

mkl_intel_c_dll.lib mkl_sequential_dll.lib  mkl_core_dll.lib

The snapshot of choices are as follows:

Warren Lake Hike

For this particular morning hike, we woke up around 4.30 am and reached the traildhead around 6.00 am. After preparations, we started our ascent. The original target was to reach Warren Lake and then continue onwards to Mt. Defiance summit. Although it was February, the weather around the trailhead was clear and not raining. We were even able to spot the stars and played with the iPhone app showing all the constellations. Finally distinguishing and seeing the Big Dipper was great.

The initial part of the hike was very steep and hit me hard. Questions like "what am I doing here?, I should be sleeping in my warm bed" started to come to my mind. But immediately the view of the Columbia Gorge albeit dark was great. So, of course we continued. Around 2500 ft the snow started and there we spotted bear tracks and became a little bit nervous. The team decided to stick together and moved forward. We moved up to 3800 ft and the weather conditions got worse. It got very cold and the snow made it very difficult to move.  So, we decided to go back even before reaching the Warren Lake. After a good breakfast, the descent was tough on the knees but the scenery of the Columbia River and the Gorge near the end of the trail was stunning.

The GPS logs and some photos are below:

 

Group velocity / Phase velocity Animation

Here, we demonstrate the group and phase velocity phenomena as observed when two signals with different temporal and spectral frequencies (wavelength) are added to each other. The addition creates time varying constructive and destructive interferences along the space. The resulting wave packet travels with the so-called group velocity which is faster than the phase velocity in this case. The wave packet envelope is shown in magenta color in dashed lines. Note that in this particular case, both group and phase velocities are positive. An important interpretation of group velocity is that it represents the velocity at which the energy or information is conveyed along a wave (see Wikipedia for further details). 

Групповая скорость, Gruppengeschwindigkeit, Voortplantingssnelheid, Velocidad de grupo, Grupa rapido, Vitesse de groupe, Velocità di gruppo, 군속도, מהירות חבורה, ჯგუფური სიჩქარე, 群速度, Gruppefart, Prędkość grupowa, Групова швидкість, 群速度, Vận tốc nhóm, Grupphastighet, Grupinis greitis Phasengeschwindigkeit, Velocidad de fase, 相速度, Vitesse d'une onde, Velocità di fase, Фазовая скорость, 位相速度

How to Automatically Parse YouTube View Statistics using importxml?

An automatic way to import YouTube video view statistics to Google Spreadsheets is to use importxml() function. In this post, a working example will be demonstrated using the following YouTube playlist:  https://www.youtube.com/playlist?list=PL38214462962EB8A0

First, the page source of the YouTube channel needs to be opened to get which parse value to use while importing the view statistics.As shown below, details of each video is listed under "video-overview" class.

<div class="video-overview">
    <h3 class="video-title-container">

      <a href="/watch?v=WRGfYqqjXDo&amp;list=PL38214462962EB8A0&amp;index=2" class="yt-uix-tile-link yt-uix-sessionlink" data-sessionlink="feature=plpp_video&amp;ei=CPbFlenq67QCFZYUIQodkUULKQ%3D%3D">
        <span class="title video-title "  dir="ltr">Corner Reflector / Retroreflector (FDTD Animation)</span>
      </a>
    </h3>

      <p class="video-details">
        <span class="video-owner">
by <span class="yt-user-name " dir="ltr">meyavuz</span>
        </span>

          <span class="video-view-count">
            151 views
          </span>
      </p>

  </div>

 Thus, in the Google Spreadsheets, we can type the following in one of the cells:

=importxml(A1,"//div[@class='video-overview']")

where cell A1 has the web address of the YouTube playlist we are working with. Once this is done, the spreadsheet will automatically populate the cells with the titles, video uploader and video views etc as shown below:

However, the cells containing the video view count also includes the user name and some other text, e.g. for this playlist, we have "by meyavuz48 views". To extract the video counts from this text, we need to use some of the functions of the Google Spreadsheets. For this particular case, typing

=value(replace(left(C1,len(C1)-5),1,10,""))

will provide the view statistics in integer form as shown below: Basically, "5" in the formula corresponds to number of characters of the word "views". Then, using the "replace" function, the first 10 characters "by meyavuz" are replaced by empty string "". Finally, the text is converted to integer using the "value()" function.

Note that using "video-overview" as the class inside importxml() function provides the titles and view count of each video. If only the video count is sought after, one can use  'video-view-count' keywords as input to the importxml function as:

"=importxml(A1,"//span[@class='video-view-count']")

Also, the full list of Google Spreadsheets function can be found in the following link:
http://support.google.com/drive/bin/static.py?hl=en&topic=25273&page=table.cs&tab=1240296