Author Archives: adrian

Laravel project returns blank page

I had this happen a couple of times so I should document it for future reference.
Copying a laravel project to another account renders some pages (pages that use templates) as blank. The change is to chmod the storage/app, storage/framework and storage/logs folders to 777.
I don’t know if all the folders need that permission, but I didn’t investigate what the minimum permissions required are.

image adjustments for inDesign and printed images

Out of inDesign, the printed material looks too dark. I get the dot gain thing, but I need to know how much to increase brightness of an image so they look proper.

I am adjusting the same image multiple times and sending that image to the printer to see how each one looks. The adjustment I’m making is Shadows/Highlights as I don’t exactly want to adjust brightness. I want the highlights to stay where they are. Curves also didn’t quite work as I intended.

shadow-highlights-adjust-panel

“Amount” is the only parameter I’ll be adjusting: 5,10,15,20,25,30% and print them to see what the effect is in print.

 

Object Oriented PHP

Some links to reading material on OO PHP

http://code.tutsplus.com/tutorials/object-oriented-php-for-beginners–net-12762

http://knowpapa.com/procedural-to-oop/

http://www.davegardner.me.uk/blog/2010/11/21/why-you-should-always-use-php-interfaces/

 

Defining relationships in databases

http://blog.andreasartori.me/defining-relationships-among-database-tables-with-eloquent/

 

Learning a MVC framework : laravel 5

Some useful links:

http://laravel.com/docs/5.0/helpers#urls

call custom files (php or otherwise) into a laravel project. For me app.php file to which I added

'Helpers'   => 'app\TradeLogic\engine'

was in config/app.php

The app.php file didn’t help.

What actually worked was adding :

include_once (__DIR__.'/../resources/views/engine.php');

to the file bootstrap/autoload.php
The path shown is from the location of the autoload file.

 

Migrations

To drop a column, need to run “composer require doctrine/dbal” otherwise a rollback that drops a column will fail.

If the filename of a migration got changed, or it got deleted, the ‘php artisan migrate’ command will complain. Need to run ‘composer dumpautoload’ shich will fix things.

Casting aluminum

Interesting thread on Casting Strength found here.
Excerpts:

Now, if you want to experiment with casting an alloy of ths type, here’s how to get out cheap;-) Find somebody who does punch work and ask them to save the slugs for you. I have a 5 gal bucket of 3003 slugs that are 3/8×3/4″ ovals, punched out at a buddy’s shop. It is the perfect size for the crucible, doesn’t require breaking up, melts really fast, and being a weldable alloy, it flows and pours like you wish everything would.

Once cast, it machines just like 3003; soft, gummy, and gooey. It makes very solid castings using the lost foam process in dry sand. Much better than scrap waterpump housings and old VW pistons. That may be the best alloy for you to use, actually. It’s soft enough to avoid cracking and, as we all know is just rediculously easy to weld. It’s not as strong as 6061, but you’ll have a really tough time making a set of castings up that will mate well under load with 6061 T6 without the casting being as big as the engine block.

and

I worked for a few years with two guys who built custom racing bike frames as a side business. Short of going to graphite composite, their preference was alloy steel tube that was silver sodlered at the joints. They used reinforcement at joints by using two tube sizes that nested and put on a tube seat of the larger tube and then inserted in the frame member to get a double wall at structural joints. They also used swaged tube that was thinner wall at midspan and heavier wall at the tube joints. The swaged tube was strictly special order only.

the reason for using silver solder was to avoid destroying the wrought grain structure at the joint. TIG welding would change the grain structure from wrought to cast structure where the metal melted, making a much weaker joint.

From experience with truck frames in the 70’s, aluminum is no substitute for steel. Aluminum truck frames were made to reduce weight and increase payload in log and flatbed trucks. However, the aluminum frames inevitably cracked and had to have reinforcing plates installed, which made the frame heavier than the steel version and still prone to cracking. It is also much less stiff than steel by a factor of at least 3.

Last thing, 6061-T6 is cast, wrought, solution annealed and then precipitation hardened. The grain structure is not quite cast, but some of the wrought structure goes away during the solution anneal. Casting 6061-T6 with a precipitation hardening process won’t be quite as strong as the T6 processing, but will be better than as-cast and will machine better. There is another type of processing, T8, which is cast, wrough, solution annealed, wrought again and then precipitation hardened which comes out stronger and harder than T6, but no stiffer.

kvm localized virtual desktops

I read something interesting the other day. Running multiple VMs, on the same computer; the catch is that they are all running on the same desktop (not headless) sharing one display. The term is “kvm localized virtual desktops”.

The place I read this was the UnRaid blog, talking about KVM integration into the UnRaid 6 system (SOURCE).

Since OpenSuSE has tools and support for kvm, I shall try this.

It would be interesting to run linux and windows and not have to dual boot, and have access to the same GPU from both OSs.

space usage

Recently came across one of my linux VM machines that ran out of disk space. But where did all the space go? What ate it up?

du -h <dir> | grep ‘[0-9\.]\+G’

This will list a sorted view of the foles/folders from largest to smallest.

(SOURCE)

Laser Diffraction pattern research

Found a few sites/companies that manufacture difracion gratings. I should contact them and get some samples.

http://worldstartech.com/products/description/60/index

http://www.lasercomponents.com/us/product/pattern-generators-for-flexpoint-laser-modules/

http://www.edphoton.com/Other%20Standard%20DOEs%20English.htm