Tech

How are things made? In this video I take a look at the different types of manufacturing processes – forming, casting, molding, machining, joining, and additive manufacturing – which are used to create the everyday objects that surround us.

Using animations, the video explores a number of different specific manufacturing techniques, like rolling, injection molding, investment casting, sand casting, and 3D printing, and gives an overview of the pros and cons of each, to help better understand how to select the correct manufacturing process.

Bill details the key engineering principles underlying plastic injection molding. He describes its history and, then,  reveals the intricate details of the process. He shows viewers where to found, on any injection molding product, the markings created by injection molding. He closes with a description of one of the finest examples of injection molding: the Lego brick. 

CSMA/CA is the networking protocol used by wireless routers (WiFi).

Why does wireless networking use CSMA/CA instead of CSMA/CD?

Hidden node problem

CSMA/CA with and without RTS/CTS

Today we start a three episode arc on the rise of a global telecommunications network that changed the world forever. We’re going to begin with computer netw…

This is an animated video explaining what a network firewall is. A firewall is a system that is designed to prevent unauthorized access from entering a private network by filtering the information that comes in from the internet. A firewall blocks unwanted traffic and permits wanted traffic.

A “Threat Vector” is the path that a hacker or a malware application might take to get past your defenses and compromise your data.

The 6 main threat vectors (points of entry) include:

• Network – The perimeter of your network, usually protected by something like a firewall. 
• User – Attackers often use social engineering and social networking to gather information and trick users into opening a pathway for an attack into a network.
• Email – Phishing attacks and malicious attachments target the email threat vector.
• Web Application – SQL Injection and Cross-Site Scripting are just two of the many attacks that take advantage of an inadequately protected Web Application threat vector.
• Remote Access – A corporate device using an unsecured wireless hotspot can be compromised and passed on to the corporate network.
• Mobile – Smartphones, tablets, and other mobile devices can be used as devices to pass malware and other attacks on to the corporate network.  Additionally, mobile malware may be used to steal useful data from the mobile device.

Your “Attack Surface” is all the publicly and privately-exposed nexus points between your company’s data and the human or software-driven interfaces of your company. In essence, it’s all your threat vectors put together.

A data center is a facility that houses an organization’s IT equipment, including servers, networking infrastructure, etc., for the purposes of hosting and storing applications and data.

The term endpoint is used in two contexts:

1. Networking – In networking, an endpoint is a remote computing device that communicates back and forth with a network to which it is connected. Examples of endpoints include:
   • Desktops
   • Laptops
   • Smartphones
   • Tablets
   • Servers
   • Workstations
   • Internet-of-things (IoT) devices
2. APIs – In APIs, an endpoint is any URL that is preconfigured to handle requests. The URL is an access point of the API. An HTTP request can be sent to the URL endpoint by a user. The server receives the request and passes it to the application (API) for processing.

Liquid Crystal Displays use an amazing array of technologies to display pictures and text. See how they work!

Important background information: Read this post on color space to understand how the RGB color system in LCD displays work.

Velocimetry is the measurement of the velocity of fluids. The fluids can be either liquid or gas. This is a task often taken for granted and involves far more complex processes than one might expect. It is often used to solve fluid dynamics problems, study fluid networks, in industrial and process control applications, as well as in the creation of new kinds of fluid flow sensors. Methods of velocimetry include particle image velocimetry and particle tracking velocimetry, Molecular tagging velocimetry, laser-based interferometry, ultrasonic Doppler methods, Doppler sensors, and new signal processing methodologies.

As an illustration of how velocimetry can be done, let’s take the method of particle image velocimetry (PIV). In PIV, the fluid is seeded with tracer particles which, for sufficiently small particles, are assumed to faithfully follow the flow dynamics. The fluid with entrained particles is illuminated so that particles are visible. The motion of the seeding particles is used to calculate the speed and direction (the velocity field) of the flow being studied.

Here is a brief video explaining Particle Image Velocimetry (PIV): https://www.youtube.com/watch?v=JbuuhpQCWz8