Analyze Thermal Effects with the Heat Transfer Module

Heat Transfer Modeling Software for Advanced Simulation

Analyze heat transfer by conduction, convection, and radiation with the Heat Transfer Module, an add-on product to the COMSOL Multiphysics® platform. The Heat Transfer Module includes a comprehensive set of features for investigating thermal designs and effects of heat loads. You can model the temperature fields and heat fluxes throughout devices, components, and buildings. To examine the real-world behavior of a system or design virtually, easily couple multiple physical effects in one simulation with the multiphysics modeling capabilities included in the software aruba certified design expert (acdx).

Specialized Features for Heat Transfer Analyses

Conjugate Heat Transfer and Nonisothermal Flow

The Heat Transfer Module contains features for modeling conjugate heat transfer and nonisothermal flow effects. These capabilities can be used to model heat exchangers, electronics cooling, and energy savings, to name a few examples.

Both laminar and turbulent flow are supported and can be modeled with natural and forced convection. It is possible to account for the influence of pressure work and viscous dissipation on temperature distribution. Turbulence can be modeled using Reynolds-averaged Navier-Stokes (RANS) models such as the k-ε, low-Reynolds k-ε, algebraic yPlus, or LVEL turbulence models. The realizable k-ε, k-ω, shear stress transport (SST), v2-f, and Spalart-Allmaras turbulence models are available when combined with the CFD Module.

The temperature transition at the fluid-solid interface is automatically handled using continuity, wall functions, or automatic wall treatment, depending on the flow model. Natural convection can be easily accounted for by activating the Gravity feature.

A nonisothermal flow modeling example of using COMSOL Multiphysics and the Heat Transfer Module.

Thin Layers and Shells

For modeling heat transfer in thin layers, the Heat Transfer Module provides specialized layer models and layered material technology to easily define complex configurations and investigate heat transfer in layers that are geometrically much smaller than the rest of a model. This functionality is available for thin layers, shells, thin films, and fractures.

For individual layers, the thermally thin layer model is used for highly conductive materials in situations where the layer contribution to the heat transfer is primarily in its tangential directions and where the temperature difference between the layer sides is negligible. Conversely, the thermally thick layer model can represent poorly conducting materials that act as a thermal resistance in the shell's perpendicular direction. This model computes the temperature difference between the two layer sides. Finally, the general model provides a highly accurate and universal model, as it embeds the complete heat equations. Layered material features support similar heat loads to the regular domain model. In particular, heat sources and sinks can be defined on layers or at layer interfaces, and heat flux and surface-to-surface radiation can be defined on both sides of the shells.

When employing the layered material technology, there are preprocessing tools for detailed layered material definition, load/save of layered structure configurations from/to a file, and layer preview features. Additionally, tools are included to visualize results in thin, layered structures as if they were originally modeled as 3D solids; specifically, surface plots, slice plots, and through thickness plot are supported. The layered material functionality is included in the AC/DC Module and the Structural Mechanics Module, making it possible to include multiphysics couplings like electromagnetic heating or thermal expansion on layered materials.

Surface-to-Surface Radiation

The Heat Transfer Module uses the radiosity method to model surface-to-surface radiation on diffuse surfaces, mixed diffuse-specular surfaces, and semitransparent layers. These are available in 2D and 3D geometries, and in 2D axisymmetric geometries when modeling diffuse surfaces. The surface and ambient properties may depend on temperature, radiation wavelength, or any other quantity in the model. Transparency properties can also be defined per spectral band (and an arbitrary number of spectral bands is supported).

Predefined settings are available for solar and ambient radiation, where the surface absorptivity for short wavelengths (the solar spectral band) may differ from the surface emissivity for the longer wavelengths (the ambient spectral band). In addition, the sun radiation direction can be defined from the geographical position and time.

The view factors are computed using the hemicube, the ray-shooting, or direct integration area method. For computationally effective simulations, it is possible to define planes or sectors of symmetry. When combined with a moving frame, the surface-to-surface radiation interface automatically updates the view factors as the geometrical configuration deforms.

Will 5G replace cable broadband networks?

Millions of people in developed countries still do not have access to broadband networks despite efforts in recent years and huge sums of money spent on connecting isolated communities.

In general, ways have been sought to expand and modernize cable networks so that everyone has access to the Internet .

With fifth-generation ( 5G ) mobile technology , which now offers considerably higher data transfer speeds than the 4G network, will we be able to give up cables altogether one day?

A 5G network supports data transfer speeds of up to 10 Gbps, has low latency or delay, and ensures the connection of up to one million electronic devices per square kilometer.

5G mobile technology allows you to download a regular high definition (HD) movie in less than 40 seconds, as opposed to more than 7 minutes via 4G mobile technology.

In fact, through 5G we can simultaneously transmit several HD videos, we can make 3D phone calls with hologram, we can access virtual reality applications, and driverless cars (autonomous) will be able to communicate with each other and the traffic infrastructure.

Unfortunately, 4G devices are not compatible with these 5G networks and to access them we need a 5G phone with a higher processing power, with a larger memory capacity (12 GB or more), but also other things like 3D holographic projectors if we want to use these features.

To access 5G networks from home we only need a 5G router.

Of course, the big challenge in replacing cable broadband networks with 5G networks is to create 5G infrastructure.

For example, UK broadband networks, which provide data transfer speeds of 24 Mbps or higher, already cover 96.4% of Internet addresses , while 5G networks are only available in major cities such as London. , Birmingham, Manchester, etc.

In order for cable data transfer speeds to be comparable to those offered by 5G, each home should be connected to the Internet with its own fiber optics.

Instead, the expansion of the 5G network requires the installation of several transmitters, connected to the fiber optic network, which can be easily accessed by a large number of users.

For this reason, it is difficult to compare the costs of each option, as both involve different infrastructure solutions.

5G Internet connection in rural areas

Connecting to the Internet for remote communities may be easier with 5G than with fiber optics. Credit: Theeraphong / Shutterstock

But providing 5G infrastructure is not everything. To compete with cable broadband providers or to replace the cable network, 5G networks must support similar data transfer speeds.

We must keep in mind that the actual speed of data transfer in mobile networks is lower than the theoretical speed.

So, although 5G theoretically supports data transfer speeds of up to 10 Gbps, the actual transfer speed in these networks can be up to 200 Mbps.

Although this speed may be sufficient for those who access the Internet only for online browsing, it may not be sufficient for users who stream multiple videos at the same time or for high-speed online gaming enthusiasts.

Another challenge for 5G mobile networks is to ensure reliable customer service, as the signals from these networks can be affected by several factors, such as the distance to the transmitter or obstacles and interference with other devices.

Improved technology: Dark Fiber

5G mobile technology providers are developing ways to overcome this problem. For example, the “massive MIMO” technology of 5G systems uses up to 96 antennas to create multiple data connections, simultaneously, between electronic devices.

Edge Computing technology (Nt An open, distributed IT architecture, characterized by decentralized data processing) involves the use of 5G towers that will process and store data without using cloud data centers, located many kilometers away .

All these features make 5G the most promising candidate to replace cable broadband networks.

Another, more difficult obstacle to developing a complete 5G network at the national level could be people's concern that this technology can be harmful to health. Even if there is no evidence of the negative health effects of 5G technology, convincing people that this technology is safe can be a challenge.

As a result, complete replacement of cable-based broadband networks with 5G networks may not be possible.

In this case, Internet users in large cities or companies may prefer cable broadband networks that are reliable, offer high transfer speeds, and are secure.

Instead, users in certain remote or rural areas will use 5G technology, as connecting to the Internet is easier than through a fiber optic network.

Always available apps with F5 Networks solutions

The most important challenge for IT departments is to provide guaranteed and secure access to business applications. Softline offers F5 Networks products designed to solve this problem.

Scope of application f5 certification

For over 20 years since its inception, F5 Networks has been developing solutions for smart application load balancing. Gartner reports its software as the leader in the Application Delivery category, which, in addition to balancing solutions, includes a variety of tools and technologies to ensure high availability, security and application performance.

F5 Networks solutions are designed for on-premises, distributed, cloud or hybrid infrastructures where mission-critical services are under heavy load, server counts and privacy requirements are high. These can be corporate business applications in the data center, the back-end of the bank-client system, social networks, online stores, government service portals and other web services.

More than 16,000 organizations worldwide use F5 Networks products, including 49 Fortune 50 companies.

Softline recommends the following F5 Networks solutions

F5 BIG-IP is the company's flagship solution. It is a hardware application delivery controller that is housed in a server rack. Has a set of software modules that work on a common platform. The client can independently choose the composition of the modules, depending on the licensing scheme.

F5 BIG-IP makes it possible to distribute the load of working servers, taking over:

load balancing of internal and geographically distant servers;

managing connections with multiple providers and choosing the most suitable connection;

analysis of packets at all levels of the OSI model, from 4th to 7th, and resisting any unauthorized access attempts;

user authentication and authorization;

caching web pages with all kinds of customization functions;

performing SSL encryption and decryption.

BIG-IP software modules run on a single TMOS (Traffic Management Operating System) platform, which ensures their maximum efficiency in collaboration and facilitates centralized management of the entire system.

F5 BIG-IP Virtual Edition is a virtual application delivery controller installed on all leading hypervisors (VMware vSphere, KVM and Community Xen, Citrix XenServer, Microsoft Hyper-V) and cloud services (Amazon AWS, Microsoft Azure, Google Cloud Platform) running on standard servers.

BIG-IP VE provides advanced application delivery services including advanced traffic control, acceleration, DNS, firewall and access control that run on dedicated hardware. VE software images are available for download and are easily ported between virtualized on-premises data centers, public and hybrid cloud environments.

VIPRION is a powerful hardware platform with the ability to increase or decrease its performance without any disruption to applications and services.

With BIG-IP solutions powered by the VIPRION platform, you can quickly deploy and scale your application delivery infrastructure to meet the changing requirements of your company. With VIPRION, there is no need to add new devices, you can simply increase the capacity of an existing platform!

With high bandwidth, connections and SSL efficiency, VIPRION can handle high workloads while maintaining high application availability and performance.

Responsibilities, tasks, skills of the system administrator (sysadmin)

Description and functions of the position of a system administrator

The profession “System Administrator” is the position of an IT specialist , whose duties include ensuring the smooth operation of computer equipment, local network and software (repair, regularly updating, setting up, etc.). And the demand for this specialty is constantly stable because no sphere of human activity can do without the use of computers linux administrator. 

Below, we present to you a list of responsibilities, skills and knowledge that are important to have in order to become a system administrator.

Is it easy to master the profession?

It is not easy to master the profession of a system administrator. mandatory requirements for a sysadmin are most often in-depth knowledge of the Windows family (for example, offices often use Active Directory to control the domain), free orientation in the hardware settings (wi-fi access points, routers, printers, etc.), the ability to organize / configure a computer local network (both physical and virtual) and so on. 

Sometimes companies hire young assistants for sysadmins (they are also called enikeys or specialists in everything), who are engaged in small tasks that often require not deep technical knowledge, but patience and free time (for example, install a program for accounting or reinstall Windows). In order to become an assistant to a system administrator, deep knowledge is not required (often people with burning eyes and a desire to learn and minimal technical skills are hired for it). With the proper approach, Enikeys gradually gain experience and in a year or two can become full-fledged administrators. 

Salary level

The salary level depends on the specialization (specializations can be, for example, a pure Windows admin, a Window / Linux admin, an admin for servicing virtualization systems such as VMware, universal specialists in all intra-office tasks), the depth of knowledge within the specialization, the size of the company and much more. Typically, the salary of a system administrator is higher than that of a technical support engineer or QA engineer (manual), but lower than that of DevOps or Developers.

Pros and cons of the profession of a system administrator

Pros:

good salary

a deep level of understanding of how modern IT works (since things that system administrators work with - from hardware to virtualization systems)

Minuses:

multitasking (many small tasks from a large number of employees)

often routine tasks (for example, reinstalling the system)

 

CCNA Discovery Course Program

CCNA1. Home and Small Business Networks

The purpose of this course is to introduce you to the basic concepts and technologies of networking. The program of the course is devoted to the practical study of tools for developing networks and using the Internet, as well as hardware specific to home and small business networks.

Upon completion of this course, you will learn to: ccna wireless

install a computer system, including an operating system, interface cards, and peripherals;

design and deploy a home or small business network and connect it to the Internet;

test and diagnose network and Internet connection problems;

organize shared access to resources (files and printers) for multiple computers;

recognize and prevent security threats to your home network;

configure and test common Internet applications;

configure basic IP services through a graphical user interface.

Hardware for a personal computer. Binary representation of data. Computer system components.

Operating Systems. Operating system maintenance.

Network connection. Getting to know the connection to the network. Data exchange in a local wired network. Creation of a distribution layer in the network. Planning the structure of the local network and connecting devices.

Internet connection through an Internet service provider. Sending information over the Internet. Laying of cables "twisted pair".

Network addressing. IP addresses and subnet masks.

Network services. Application protocols and services.

Wireless technologies. Wireless local area networks. Securing your wireless LAN.

Security basics. Using firewalls.

Eliminate network problems. Troubleshooting questions. Common problems.

CCNA2. Work for small and medium-sized enterprises and Internet providers

The course is aimed at developing the practical skills you need to manage the network infrastructures of computer networks as certified technical support consultants and entry-level networking specialists.

Upon completion of this course, you will learn to:

describe the structure of the Internet and the procedure for exchanging data between nodes in the global network;

install, configure and test Cisco routers designed to provide access to the Internet and servers;

design the basic cabling infrastructure to support network traffic;

configure the server to provide shared access to resources and common web services;

deploy a global network using the services of telecommunications companies;

take appropriate measures to prevent the consequences of accidents and back up information on the server;

monitor network performance and detect malfunctions;

troubleshoot using an organized, multi-tiered procedure;

describe the OSI model and data encapsulation process.

Internet and the possibilities of its use. What is the Internet? Internet service providers. Communication with an Internet provider.

Support service. Support technicians. OSI model. Troubleshooting at the ISP level.

Planning for network upgrades. Common problems. Planning for network upgrades. Purchase and maintenance of equipment.

Planning the addressing structure. LAN IP addressing. NAT and PAT.

Configuring network devices. Initial configuration of the ISR router. Configuring ISR in SDM. Configuring the router using the IOS CLI. Initial configuration of Cisco 2960 switch. CPE connection to ISP.

Routing. Application of routing protocols. External routing protocols.

Services of Internet providers. An introduction to the services of Internet providers. Protocols used to provide services by providers. Domain Name Service. Services and protocols.

Obligations of providers. Security issues relevant to ISPs. Security tools. Control and management by the Internet provider. Backup and disaster recovery.

Eliminate network problems. Troubleshooting questions. Common problems.

CCNA3. Introduction to Routing and Switching in the Enterprise

The goal of this course is to help you develop the skills to use protocols to increase the performance of your LAN and WAN. The course introduces advanced configurations of switching and routing protocols, configurations of access control lists, and the basics of implementing WAN links. In addition, the course provides detailed troubleshooting guides for LAN, WAN, and VLAN environments. The course aims to develop the practical skills required to work as network technicians, helpdesk technicians, and computer technicians.

Upon completion of this course, you will be able to:

implement a LAN in accordance with the approved network design;

configure a switch with VLAN and the connection between switches;

configure routing protocols on Cisco devices;

implement access lists to allow or deny specified traffic;

introduce DHW channels;

troubleshoot LAN, WAN, VLAN problems using a structured methodology and OSI model.

Corporate networks. Description of the corporate network. Identification of corporate applications. Support for remote workers.

Exploring the corporate network. Description of the existing network. Support for the corporation border. Repetition of passed on switching and routing.

Switching in the corporate network. Description of enterprise-grade switching. Prevention of switching loops. VLAN configuration. Trunking and routing between VLANs. VLAN service in the corporate network.

Addressing in the corporate network. Using a hierarchical IP network addressing scheme. Using VLSM. Using classless routing and CIDR. Using NAT and PAT.

Routing using a distance vector protocol. Corporate network management. Routing using the RIP protocol. EIGRP routing. Implementation of the EIGRP protocol.

Link State Routing. Routing using the OSPF protocol. Single area OSPF implementation. Using multiple routing protocols.

Creation of corporate WAN channels. Connecting the corporate WAN. Comparison of common WAN encapsulations. Using Frame Relay.

Filtering traffic using access control lists. Using Access Control Lists. Using a group mask. Setting up access control lists. Allowing and blocking certain types of traffic. Filtering traffic using access control lists.

Troubleshooting the corporate network. Consequences of a network failure. Eliminate switching and communication problems. Eliminate routing problems. Troubleshoot WAN configuration problems. Troubleshoot ACL problems.

What are the types of fiber optic cables?

Optical modes are simply the path that a ray of light travels along a fiber. One mod goes right in the middle. The other can bounce off the fiber at narrow angles. Other modes bounce off the fiber at different angles.

The simplest fiber type is singlemode. A very thin core (5-10 microns) sends signals directly down the center without bouncing off the shell. Internet, cable TV and telephone signals are most often transmitted over single-mode fibers, which are bundled into a huge package. These cables can carry information over 60 miles.

Each fiber in a multimode cable is almost 10 times larger than in a singlemode cable. This allows light rays to travel through the core in different paths - in multiple modes. The disadvantage of multimode fiber optic cables is that they can only transmit information over short distances. They are mainly used to link computer networks fiber installation.

How are fiber optic cables made?

Fiberglass is surprisingly strong considering that glass is a fragile material. Most optical fibers are made by pulling a glass rod, heated to the melting point, a few centimeters in diameter and about 1 m long, into a thin fiber 125 micrometers in diameter and several kilometers long.

Each of these fibers is wound together with similar fibers to produce a thicker thread. However, additional protection is often needed when fibers are used in an environment where access is open. For laboratory use, where researchers send “light from a telecommunications facility to a diagnostic device,” and in large industrial assemblies, it is convenient to use fiber patch cords, where the actual fiber is surrounded by additional protective layers. While bare glass fiber can have a typical diameter of 125 micrometers, and the polymer buffer and jacket increase it to a few hundred micrometers, the total fiber cable diameter can be several millimeters."

This not only strengthens the cable, but also makes it easier for operators to recognize the fiber for ease of maintenance and repair. And a fiber optic cable can contain multiple fibers. This allows the already enormous data transmission capabilities of a single fiber to be multiplied. There are many optical components that can be made directly from fibers. Some examples include

Fiber connectors that conduct light between two fibers

Optical filters for use in introducing chromatic dispersion into the system

Fiber polarizers made with polarizing fibers to direct light in a specific direction of polarization

Fiber amplifiers that amplify light at specific wavelengths

These are just a few examples of how fiber optics are made and what we can make from them for use in many areas.

Partnering with Cisco helps us promote IaaS and change our approach to IT in the Czech Republic

It is not easy to be a pioneer, especially in the field of information technology. Users look at your product and think, "They never get caught." Remember the days when the only Internet users were government agencies, research institutes, and universities? Ordinary consumers were happy with services like CompuServe or AOL, and the web was too complicated for them. Fortunately, companies like Google have joined in and changed the perception of the Internet.

The iPhone initially seemed like an absurd idea. After all, who would exchange their BlackBerry for a device without a keyboard? But look today. Everything is tactile and consumers are used to typing on the screen.

Seize the opportunity where others see the risks ccie data center jobs

When something really big arises, it is usually preceded by the boundless commitment and great intuition of the provider, as well as the equal trust and conviction of the users. Where others see only risks, the greatest opportunities are most often hidden and need to be seized. My partner Tomáš Knoll and I found ourselves in such a situation in 2011. At that time, we both worked at Cisco in Prague and it began promoting cloud services - both in the form of local and private data centers and externally in the form of service infrastructure (IaaS).

Where others see only risks, the greatest opportunities are most often hidden and need to be seized.

Although Cisco and VMware brought these technologies to the Czech market, there were no service providers offering basic or advanced cloud services to medium and large enterprises. So we set up Cloud4com to fill a gap in the market. 

At that time, Czech companies were very reluctant to introduce cloud technologies. Hosting data or applications on third-party infrastructure contradicted the prevailing views on enterprise IT at the time. 

Most of the people who held senior IT management positions in 2011 started work around 1989, and their decision-making was therefore still burdened by the experience of the communist regime. For someone else to have access to their data was the last thing they cared about. It was like going back to the era of ubiquitous spying, regardless of the number of guarantees we offered.

We educate customers and build trust to create a new market

To reverse this way of thinking, we spent the first few years at Cloud4com educating potential customers and explaining the reliability and security of cloud applications and infrastructure. It was a cruise upstream. Sometimes it was difficult to explain our arguments, but we knew it made sense. The emerging IaaS market was too tempting an opportunity to miss. Being first in Prague and the Czech Republic meant being able to set the direction and manage the expectations of the first customers. 

Do not change the market, but its thinking.

Because credibility came first for potential customers, we had to prove to them that they could trust us. We have achieved this in two ways. Ownership of the leased infrastructure and partnership with a reputable technology supplier, which enjoyed a reputation for reliability and safety, proved to be essential.

Cisco was a clear choice. As former employees, we knew its technology perfectly, but more importantly - the Czech market recognized it as the most important supplier of IT infrastructure. Cisco's reputation was a guarantee we needed to promote Cloud4com services as an important enterprise IT innovation.