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Tomorrows Solar Eclipse from Beirut

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I have stumbled upon several posts and discussions on social networks, and some have contacted me about whether the eclipse is visible from Lebanon or not and about the timing.
I am writing this post to address some of your confusions. Here’s a general video from NASA’s Jet Propulsion Lab to start with:

Following is a visualization of the eclipse. The greatest eclipse (totality) occurs above the Faroe Islands, halfway between Norway and Iceland, around 1200 hours Beirut time.
In the visualization below, the strip formed by the two blue curves within which the greatest eclipse occurs is the path of totality. This is the path the shadow due to the moon blocking the Sun’s light from us follows. The further on Earth the observer is from this path the smaller the percentage of the eclipse is observed. Read on for more details.

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Banque du Liban (BDL) Accelerate 2014 – First Startup Conference in Lebanon

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Banque du Liban (BDL), or the Central Bank Of Lebanon, is organizing the first international startup conference in Beirut, Lebanon. The conference is known by “Banque du Liban Accelerate 2014”. Accelerate 2014 will be a melting point for entrepreneurs, startup companies, investors, and a select of highly prolific and successful people including ambassadors, ministers, industry leaders and professionals. And there will be fifty speakers (see below) who are mostly successful entrepreneurs and startup founders.

It is an invitation-only conference whose theme was chosen to be Blueprints for Success. BDL is aiming that the conference be a building block that supports current and new startups in Lebanon and help to accelerate their development and success, hence the “Accelerate” name and the theme “Blueprints for Success”.

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Lebanese face unprecedented water problems

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Water shortages due to low precipitation levels and lack of nation-wide water management

Lebanon has long been a country abundant in water and as such most Lebanese have taken water for granted thinking that they will never have a shortage in or problems with it.

It was apparent that this year has had very little rain [1,2]. Indeed the numbers indicate that the precipitation levels have not even reached half the average annual of 900 ml. This, of course, has led to a huge deficiency in water reserves [3,4]. But the main problem does not lie in the low precipitation levels this year rather it lies in the incompetence of the Lebanese authorities “and most Lebanese” to manage and conserve water.

On one hand, the authorities have not been doing their job of investing in the main source of life by managing the water (and sewage as a matter of fact; see below on this) in order to effectively exploit it and not waste it. They have not been working on conserving this abundance in water by preventing leakage, building dams, replenishing underground reservoirs, introducing artificial ponds, or dealing with the r
andom wells being dug and un-licensed water suppliers.

This is demonstrated in what Claude Tabbal, an expert on the water resources in Lebanon, said to Azza el-Masri and Raed Khalil of the Al-Akhbar newspaper [4] on June 26:

”We get 800 cubic meters of water per year, but up to 65 percent of it is lost each year”

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Quantum Harmonic Oscillator: Power series method in Maple

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In the previous blog post What is Computational Physics (Science)?, I ended the post with the following figure

Graph of the probability distribution of the 100th state of the quantum
harmonic oscillator (generated using the power series method).

and stated that I might write a post on how to solve the Quantum harmonic oscillator numerically using the power series method (the other method being the ladder operator method [1]) and generate that figure. This post is just about that.

Ok. First I need to clear the cache with the restart command, import the PDEtools (to solve the pde SE) and Maplets[Elements] (necessary if you want to generate a maplet with a slider) packages.

restart;
with(PDEtools): #we need to use the dchange command later in the solution
with(Maplets[Elements]):

Useful Unix/Linux commands

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$ indicates terminal command
# indicates a comment
Bold indicates “not installed by default”
$ lsusb     #list USB devices
$ lspci     #list all PCI devi
$ startx    #initialize an X session
$ more      #filter for paging through text one screenful at a time. (less gives more advanced).
$ less      #opposite of more; allows backward movement in the file as well as forward movement.
$ stty      #change and print terminal line settings
  $ stty size # prints terminal size

File commands

$ locate            #find files by name (for newbies I suggest the gui catfish -requires installation)
$ find              #search for files in a directory hierarchy
$ ls                #list directory contents
$ cd                #change directory
$ pwd               #print name of current/working directory
$ cp                #copy files and directories
$ rm                #remove files or directories
$ rmdir             #remove empty directories
$ file foo.format   #extracts info about file and what software it was written with; helpful in the case of having forgot which software was used to produce such a file

System info

$ uname
$ df                         #report file system disk space usage
                             #e.g; df or df /home
$ man                        #interface to the on-line reference manuals
$ free                       #Display amount of free and used memory in the system
                             #e.g; free -mt (m for MB & t for totals line)
$ uptime                     #tell how long the system has been running.
$ finger                     #user information lookup program
$ w                          #show who is logged on and what they are doing.
$ whoami                     #print effective userid
$ cat /proc/meminfo          #memory info
$ cat /proc/cpuinfo          #cpu info
$ lsb_release -a             #print (a: all ) distribution-specific information
$ last -x | grep shutdown    #show listing of last 10 logged in users; you can pipe this to the tail to read the last n instances.
                             #e.g; for 10 instances: last -x | grep shutdown | tail -n 10
$ last -x | grep reboot      #show listing of last logged in users
$ sudo shutdown -P hh:mm     #shutdown & poweroff (-P) @ hh:mm

Processes

$ uname
$ ps               #report a snapshot of the current processes.
$ top              #display Linux tasks
$ htop             #interactive process viewer based on top
$ watch            #execute a program periodically, showing output fullscreen
                   #e.g; watch -n 5 free -m
$ powertop         #program to analyze power consumption on Intel-based laptops
$ kill pid         #send a signal to a process
$ killall proc     #kill processes by name
$ pidof program    #find the process ID of a running program

Some useful terminal shortcuts

Ctrl+C #halt the current command
Ctrl+Z #pause command
$ fg #resume paused command in foreground bg resume paused command in background
Ctrl+D #logout of current session (similar to exit)
Ctrl+W #erase last word before cursor
Ctrl+U #erases the whole line
Ctrl+R #type to bring up a recent command
I hope this list turns out to be useful to you 🙂

Thanks for reading

last update: 2014-11-03