Setting up a LAMP&MAIL server

1,Get a free SSL-Cert or cheap one
https://www.digitalocean.com/community/tutorials/how-to-set-up-apache-with-a-free-signed-ssl-certificate-on-a-vps
StartSSL™ Comparison Chart
Is it okay to use the FREE SSL Certificate offered by: Instant SSL by comodo? or Is StartCom better? [closed]
You Can get less than $10/year fro cert from namecheap

#cat ssl.crt sub.class1.client.ca.pem > /etc/ssl/certs/dovecot.pem
#mkdir /etc/ssl/private
# openssl rsa -in ssl.key -text > ssl-private.pem
# cat ssl-private.pem > /etc/ssl/private/dovecot.pem
#chmod 644 /etc/ssl/private/dovecot.pem
#chmod 444 /etc/ssl/certs/dovecot.pem

Setting up an SSL secured Webserver with CentOS

2,setting up the mail server
Running a Mail Server
Email with Postfix, Dovecot, and MySQL on Ubuntu

3,It’s OK to use a Selfsigned SSL for mail server
It is definitely worth enabling SMTP TLS if you can, whether or not you pay for a third-party-signed certificate.
If you are concernced about your mail being marked as spam, consider setting up SPF and DKIM.

桥梁工程作业1

这些来源于公开资料,有版权的人不要起诉我索赔1000亿美元啊,1亿美元的律师费,我穷得没有钱赔.

桥面板计算
作业1:单向板内力计算
条件:①桥主梁跨径为19.5m,桥墩中心距为20m,横隔梁间距4.85m,桥宽为5×1.8+2×0.75=10.5m,主梁为5片。铺装层由沥青面层(0.03m)和混凝土垫层(0.09m)组成。板厚120mm,主梁宽180mm,高1300mm。②桥面荷载:公路Ⅰ级
要求:确定板内弯距
桥面板
作业2:铰接悬臂板内力计算
已知:铰接悬臂板,公路-Ⅰ级;桥面铺装:5cm沥青混凝土面层,γ1=24kN/m3;平均8cm厚C30号混凝土垫层,γ2=25kN/m3;T梁翼板:γ3=25kN/m3。
求算:设计内力
铰接板

横向分布系数计算
作业1:用杠杆原理法求支点处各梁的横向分布系数
条件:如图所示一桥面净空为净-8.5+2×1.0m人行道的钢筋混凝土T梁桥,共5根主梁。
要求:求荷载位于支点处时各梁的荷载横向分布系数

杠杆法

作业2:用偏心压力法求跨中处各梁的荷载横向分布系数
使用上题的图,各主梁横截面相同,计算跨径为19.5m。
要求:求荷载位于跨中处时各梁的荷载横向分布系数

作业3:铰接板荷载横向分布系数计算
所示为计算跨径 =15.60m的铰接空心板桥的横截面布置,桥面宽度为净-7+ 人行道。全桥由9块预应力混凝土空心板组成,试求1号、3号和5号板在汽车荷载和人群荷载作用下跨中荷载横向分布系数 。
板梁桥
上图单位厘米
板梁截面
上图单位毫米

MyLinux&VPS Experience

I started my first VPS at hosthaus two years ago. It was a single vCPU with 128MB of memory and 5GB of Disk space. Internet connection is limited to 50GB/Month. Price was low at that time,$50.00 for two years.

I installed asterisk and use it as my telephone and proxy server. I’m happy with it.

It give me great experience about Linux and Opensource software.

The internet Speed at hosthaus is very low for my new service, I must move on. I have new VPS at Digital Ocean and a dedicated server at OVH’s So You Start.

I got my second VPS at Digital Ocean about 50 day ago. It’s 1vCPU ,512MB ram, 10GB ssd disk space with 1TB internet traffic per month. It’s only $5/Mon. This is much faster than the old one. I’m happy with it.

This is the differences of Internet connection:(testing tool https://freevps.us/downloads/bench.sh)

Hosthaus@Phoenix
CPU model : QEMU Virtual CPU version (cpu64-rhel6)
Number of cores : 1
CPU frequency : 2600.154 MHz
Total amount of ram : 118 MB
Total amount of swap : 263 MB
System uptime : 70 days, 18:40,
Download speed from CacheFly: 2.73MB/s
Download speed from Coloat, Atlanta GA: 461KB/s
Download speed from Softlayer, Dallas, TX: 771KB/s
Download speed from Linode, Tokyo, JP: 548KB/s
Download speed from i3d.net, Rotterdam, NL: 306KB/s
Download speed from Leaseweb, Haarlem, NL: 1.03MB/s
Download speed from Softlayer, Singapore: 247KB/s
Download speed from Softlayer, Seattle, WA: 727KB/s
Download speed from Softlayer, San Jose, CA: 1.15MB/s
Download speed from Softlayer, Washington, DC: 843KB/s
I/O speed : 35.6 MB/s

Cheap all-in-one computer@Shenzhen
CPU model : Intel(R) Celeron(R) CPU J1900 @ 1.99GHz
Number of cores : 4
CPU frequency : 1328.000 MHz
Total amount of ram : 15947 MB
Total amount of swap : 0 MB
System uptime : 53 min,
Download speed from CacheFly: 1.12MB/s
Download speed from Coloat, Atlanta GA: 691KB/s
Download speed from Softlayer, Dallas, TX: 1.37MB/s
Download speed from Linode, Tokyo, JP: 100KB/s
Download speed from i3d.net, Rotterdam, NL: 486KB/s
Download speed from Leaseweb, Haarlem, NL: 934KB/s
Download speed from Softlayer, Singapore: 1.90MB/s
Download speed from Softlayer, Seattle, WA: 1.04MB/s
Download speed from Softlayer, San Jose, CA: 149KB/s
Download speed from Softlayer, Washington, DC: 1.41MB/s
I/O speed : 48.7 MB/s

Digital Ocean@Sn Francisco
CPU model : Intel(R) Xeon(R) CPU E5-2630L 0 @ 2.00GHz
Number of cores : 1
CPU frequency : 1999.999 MHz
Total amount of ram : 498 MB
Total amount of swap : 0 MB
Download speed from CacheFly: 67.7MB/s
Download speed from Coloat, Atlanta GA: 20.0MB/s
Download speed from Softlayer, Dallas, TX: 36.3MB/s
Download speed from Linode, Tokyo, JP: 17.2MB/s
Download speed from i3d.net, Rotterdam, NL: 6.25MB/s
Download speed from Leaseweb, Haarlem, NL: 18.9MB/s
Download speed from Softlayer, Singapore: 9.51MB/s
Download speed from Softlayer, Seattle, WA: 54.7MB/s
Download speed from Softlayer, San Jose, CA: 66.6MB/s
Download speed from Softlayer, Washington, DC: 2.73MB/s
I/O speed : 319 MB/s

SoYouStart@Montreal
CPU model : Intel(R) Xeon(R) CPU E3-1245 V2 @ 3.40GHz
Number of cores : 8
CPU frequency : 1600.125 MHz
Total amount of ram : 32186 MB
Total amount of swap : 59997 MB
System uptime : 7 days, 16:26,
Download speed from CacheFly: 99.0MB/s
Download speed from Coloat, Atlanta GA: 17.6MB/s
Download speed from Softlayer, Dallas, TX: 30.4MB/s
Download speed from Linode, Tokyo, JP: 12.8MB/s
Download speed from i3d.net, Rotterdam, NL: 7.94MB/s
Download speed from Leaseweb, Haarlem, NL: 33.3MB/s
Download speed from Softlayer, Singapore: 5.77MB/s
Download speed from Softlayer, Seattle, WA: 16.1MB/s
Download speed from Softlayer, San Jose, CA: 18.6MB/s
Download speed from Softlayer, Washington, DC: 36.2MB/s
I/O speed : 142 MB/s