Water Desalination Methods for Water Resource Engineers

Table of Contents

1. Introduction

2. Desalination Process

3. Technologies Used for Water Desalination

4. Advantages of Desalination

5. Disadvantages of Desalination

Introduction

The ocean covers up to 70% of the earth's surface and makes up 96% percent of the water on the planet. The earth consists of only 3% fresh water, and 75% of that fresh water is frozen. Today, most developing countries across the globe are suffering from a shortage of fresh water. To help solve this, professional water resource engineers and scientists introduced a new technology for converting saline water into fresh water so that there is enough fresh water supply for necessary activities including drinking, growing crops, and bathing. 

Desalination Process

Desalination is the process of removing various minerals and salts from the water that causes salinity. 

Technologies Used for Water Desalination
Thermal desalination includes boiling, evaporation, and condensation.
The types of desalination processes are:
1)Flash distillation method
2)Solar water desalination method
3)Reverse osmosis water treatment

Advantages of Desalination 

1)Provides a large amount of water resources for drinking and agricultural purposes
2)Provides distilled water, and therefore, prevents the formation of scales in boilers

3)Areas with a scarce supply of fresh water are able to produce their own crops

Disadvantages of Desalination 

1)Consumes a large amount of energy and expenses
2)Process requires adding chemicals to the water that may cause harm to marine ecology and the environment
3)Consumes more time for processing and is a continuous process

Public water supply projects in areas with a scarce supply of water have adopted the desalination process as the main water treatment method to generate fresh water for public consumption.

Structural Engineering Standards for Historical Buildings' Preservation and Maintenance

Table of Contents

1. The structural importance of preserving historical buildings

2. Renovations and Maintenance of Historical Buildings

3. Renovation and Maintenance Methods

The structural importance of preserving historical buildings

History plays an important role in providing knowledge about a country's culture, civilizations, beliefs, and religions. Historical buildings represent the past of that particular region and inform people about past structural constructions. The importance of the structural maintenance of historical buildings is to value history over progress. The major controversial issue surrounding historical buildings is whether to maintain them or demolish and replace them. While some people believe that it is important to maintain those buildings due to their historical value, others believe these buildings stand in the way of development. 

It is very important to maintain historical buildings because they have cultural significance and economic value. However, it is not always possible to maintain historical buildings due to supporting construction costs and the availability of space around the existing structure. Historical buildings should be well-maintained, protected, and modernized for future generations. Structural engineering aspects and building codes govern the preservation and maintenance of these buildings. SE exam review courses cover the structural engineering standards and building codes for maintenance.

Renovations and Maintenance of Historical Buildings

There are various structural engineering standards that are used to assist with the long-term protection of historical buildings and features. The construction materials used in historical buildings are mainly from natural resources. The structural engineering procedures address the treatments of preservation, rehabilitation, and renovation based on the architectural value and heritage, construction technology, construction materials, design, and existing condition. If the historical building is to be kept in good condition for public access, periodic maintenance is essential. Historical buildings should be inspected often for maintenance issues; many historical buildings require serious repairs. Damaged structural elements should be renovated whenever possible. If renovation is necessary, the new material should match with the historical material in design, color, and other visual elements. The process of renovation and maintenance of the historical building should be inspected by professional structural engineers with their SE exam certification. For many repairs, knowledge of structural engineering techniques may be required. Most of those techniques are covered in structural engineer exam review courses.

Renovation and Maintenance Methods 

Selection methods and techniques are based on the type of structure and its age. In the engineering practice, preservation and restoration are the desired methods. These methods reduce construction cost and time that is usually spent on construction and transportation of construction materials. Rehabilitation treatment highlights the retention and repair of historical structural elements. The public often views constructing a new building as more beneficial and economical instead of preserving an old building. However, preserving a historical building is a form of conservation.

Stormwater Management Practices for Healthy Environmental Engineering Activities

Table of Contents

1. Introduction

2. Parameters Influencing Stormwater Management practices

3. Stormwater Management Practices and Common Problems

Introduction

The main objective of this article is to explain the importance of stormwater management. Stormwater runoff is mainly from rains or through melting snow that does not penetrate into the natural ground. Stormwater collects from residential buildings, Parking lots, Asphalt pavements, and thru Natural vegetation. Stormwater runoff collects and carries decayed dead animals, organic waste, roadside trash, sediments due to soil erosion and other pollutants. Earlier days, Ponds are used effectively to manage stormwater. Stormwater management practices can be used efficiently to prevent erosion of loose soil and as well as flooding of wetlands. Considerable amount of groundwater quantity increases the probability of flooding frequency, stream channel slope instability. Uncontrolled stormwater runoff damages highway and utility infrastructure. The goal of best stormwater management is to protect groundwater and surface water systems from pollution for current and future generations. NPDES and EPA storm water management practices are most important topics for PE exam and they are thoroughly discussed in PE exam review course.

Parameters Influencing Stormwater Management practices

The need of stormwater management is to maintain water quality and quantity. Stormwater management systems should employ water treatment methods for collecting and purifying stormwater. Treated stormwater can be discharged into the natural streams or rivers. There are various methods to control stormwater runoff. Some of the methods are developing shrubs and swales, sodded ditches, and filter fabric systems. These methods are best and they are simple to construct and as well as for maintenance. Stormwater management also helps in preventing structural damages and flooding near construction sites. Stormwater runoff also considered as water resource that helps to increase groundwater table level and also natural stream levels.

Stormwater Management Practices and Common Problems

Water Resources and Civil Engineers facing problems in maintaining water quality with controlled turbidity levels during heavy stormwater runoff situations. The main task of stormwater management team is to manage retention ponds, treating the collected stormwater prior to discharge into main stream channel without affecting existing drainage facilities. Many agencies and local stormwater management bodies are insisted to design new systems that keeps groundwater environmentally safe and free from pollutants. Environmental protection of wetlands is one of the critical problem, where most of the water resources engineers are facing. Due to global climate changes and unanticipated high intensity of rainfall managing the flooding events is difficult task. It is on the shoulders of water resources engineer to estimate the runoff from all sources to design drainage facilities.Highway engineers should provide surface runoff calculations to estimate drainage structures intake capacity. Engineers with Professional Engineer Exam Certification will allowed to provide design calculations for the drainage structures.

Role of Bearings in Mechanical Engineering Applications

Table of Contents

1. Introduction

2. Bearings and Mechanical Applications

    2.1 Ball Bearings

    2.2 Roller Bearings

    2.3 Ball Thrust Bearings

    2.4 Roller Thrust Bearings

    2.5 Tapered Roller Bearings

    2.6 Sliding Contact Bearings

    2.7 Rotary Motion Bearings

    2.8 Specialized Bearings

Introduction:

Bearings are machine elements that allow components to move with respect to each other. There are two types of bearings: contact and non-contact. Contact-type bearings have mechanical contact with equipment, which includes sliding, rolling, or flexural bearings. Non-contact bearings include liquid, air, mixed phase, and magnetic bearings. The lack of mechanical contact eliminates static friction. PE Mechanical exam review courses cover industrial applications and material properties of bearings. 

Every bearing type has its own application area. Every mechanical engineer should be aware of the applications and limitations of each bearing type as well as the fundamental operating principles of different bearings so that the correct bearing for the intended application can be selected. Our PE Mechanical review course recaps the fundamentals of bearings and their applications.

Bearings and Mechanical Applications:

Ball Bearings

Ball bearings are a very common type of bearing, as they handle both radial and thrust loads. However, they can handle only a small amount of weight. These can be found in a wide range of applications such as roller blades and hard drives.

Roller Bearings

Unlike ball bearings, roller bearings are equipped to carry large loads. The load distribution is spread over a wide area as the primary roller is in the form of a cylinder to carry large loads. However, these bearings cannot handle thrust loads. If there are space constraints in the equipment, needle roller bearings need to be used. 

Ball Thrust Bearings

This type of bearing is designed for applications specified for low speed and low weight that can carry a thrust load. An example of a ball thrust bearing is a bar stool used to support a seat. 

Roller Thrust Bearings

These bearings are similar to ball thrust bearings as they are designed to exclusively handle thrust loads. However, unlike ball thrust bearings, they can handle larger loads. These bearings can be found in a wide range of applications including helical gears in car transmissions.

Tapered Roller Bearings

Unlike ball bearings, tapered roller bearings can handle both large thrust and radial loads. These bearings are used in automobile transmissions, which contain huge thrust and axial loads.

Sliding Contact Bearings

A wheel on a simple axle with sliding contact between the two is one of the most common types of bearings. Bushing is a sliding contact radial bearing element used to support a shaft and have integral flanges to support axial loads. Sliding contact bearings are commonly used for low and modest speed applications.

Rotary Motion Bearings

This anti-friction bearing is often used for rolling elements, such as balls or rollers, which reduce friction. The rolling element is normally constrained between a ring (inner race) and another ring (outer race). A cage typically acts as a separator and keeps the rolling elements apart to prevent rubbing. 

Specialized Bearings

For some specific applications, specialized bearings are produced similarly to giant roller bearings for handling extremely large loads and magnetic bearings for high speeds.

Mechanical engineers preparing for the PE exam should be familiar with engineering applications of bearings.

Wind Energy as an Alternative Source for Electric Power Generation

Table of Contents

1. Introduction to wind energy systems

2. Working principle of wind energy systems

3. Environmental & social impacts of the wind power system

Introduction to wind energy systems

Wind energy is the best source of electric power generation that is mainly from blowing wind across the earth's surface. Turbines develop kinetic energy and change it into electric power, which can provide electricity for household and business applications on small, medium, and large scales. Wind energy is the fastest growing technology of new electricity generation. The growth of wind energy has multi-dimensional benefits like its green power, sustainability and affordability. The earliest wind power technology principle is the sail boat, which influences later developments of sail-type windmills. During 500-900 A.D, Persia developed the first windmills to automate the jobs of grain-grinding and pumping water. The earliest design of wind energy is the vertical axis system. Wind energy is the fastest growing source of energy across the globe. Wind energy is efficient, cost effective, and does not cause pollution. Wind energy is currently one of the lowest cost options for renewable energy technologies. Industrial wind energy has become a valuable energy source. The energy generated from wind is free of pollution. Wind energy helps to ensure that electric demands are met. A small wind energy system is an economical source of electricity for domestic purposes. With large electric power projects, the need for structural engineers to design and execute the construction of electrical grid towers is great. Qualified professional structural engineers with their SE exam certification approve and sign as-built plans of structural engineering power grid tower systems.

Working principle of wind energy systems

The mechanical system of wind rotates the turbine blades to a considerable amount of speed by a shaft that connects to a generator to produce electricity. Renewable solar energy is energy generated from natural resources like sunbeams, wind, rain, and geothermal heat, which are naturally replaced. Wind electric systems are the most cost-effective renewable energy systems. Wind energy systems are connected to the electricity distribution system and are known as grid-connected systems. A grid-connected wind turbine system can reduce the consumption energy of electricity for lights, appliances, and electric heat. If the turbine generates more electrical power than the facility requires, the excess electricity is sold to the utility companies. Commercial production turbines are used to generate electric power, and they are three-bladed and pointed to the wind by computer-controlled motors. This kind of turbine has a high speed of up to six times the wind speed, high efficiency, and the speed of torque ripple is low, which contributes to good reliability. Reliability of the power structure system depends on the structural engineering calculations for various acting forces on members of towers. The calculation of tension and compression in the members is important for structural stability. Structural engineers are well aware of those calculations in their Structural Engineer exam preparation refresher course. 

Environmental & social impacts of the wind power system

Wind energy provides an effective way of producing electric power for individuals or businesses. Wind turbines can be constructed in the form of vertical axis and horizontal axis. The most common type of wind turbine is horizontal. Wind turbines are used across the world. Wind energy is versatile and has both advantages as well as disadvantages that make it a bit difficult to implement on a large scale. Wind turbines have some effect on wildlife and the nearby environment. Wind energy does not pollute the air unlike power plants that depend on the combustion of fossil fuels. Wind turbines do not produce acid rain either. Wind power factories may be destructive sources of local environments. Wind turbines may cause environmental damage, and fragile ecosystems can be destroyed. Wind turbines are harmful to birds and other wild animals. Sound pollution may cause health hazards and nervous disorders in nearby neighborhoods. Out of all types of loads for assessing the stability of the structure, wind load is critical and has the tendency to uplift the structure. The types of loads and their load factors for design calculations are discussed in the SE exam review course.