Monday, 24 April 2017

Effects of Air Pollution on the Environment

Introduction 

Air pollution occurs when harmful gases, dust, or smoke enters the atmosphere and has a negative impact on plants, animals, and/or humans. Air pollution is the deadliest form of pollution, killing millions of people each year. The World Health Organization reports that more than 92% of the world’s population lives where air pollution exceeds safe limits. Among all other pollutants, air pollution has proven to be a major concern throughout the world. Air pollution and its impact on the environment creates an increasing demand for environmental engineers with their PE license. 

PE Environmental Review Course

Air Pollution Hazards

Air pollution hazards are thoroughly discussed in our PE Environmental review courses. Air pollution can cause many problems including: 

1)Acid rain
2)Eutrophication
3)Haze
4)Negative effects on wildlife
5)Ozone depletion
6)Crop and forest damage
7)Global climate change

Acid Rain

Acid rain is formed when sulfur dioxide and nitrogen oxide in the atmosphere is mixed with rainwater as a weak sulfuric and nitric acid. Acid rain can damage crops, plants, and aquatic life and is even capable of damaging structures. 

Eutrophication

Eutrophication is a condition created by using excessive fertilizers and pesticides that drain into bodies of water. Nutrients, such as nitrogen, stimulate blooms of algae, which in turn endangers aquatic life.

Haze

Haze is formed when sunlight encounters suspended pollutant particles in the air. Haze obstructs our vision, clarity, color, texture, and form of what we visualize in the real world. 

Negative Effects on Wildlife

Like humans, wild animals are also developing health problems as they are exposed to toxic air. Air toxins contribute to birth defects, reproductive failure, and disease in wild animals and aquatic ecosystems.

Ozone Depletion

Ozone is a gas that is present in the earth's upper atmosphere, the stratosphere. Ozone forms a layer that protects life on Earth from the sun's harmful ultraviolet (UV) rays. Ozone is gradually being destroyed due to ozone-depleting substances being released into the atmosphere. The thinning of the protective ozone layer is causing higher amounts of UV radiation to reach the earth, leading to more cases of skin cancer, cataracts, and impaired immune systems. UV rays also damage crops and lead to reduced yields. 

Crop and Forest Damage

Air pollution damages crops and trees in many ways. Air pollution reduces growth and the survivability of plant seedlings and increases plant susceptibility to disease, pests, and other environmental stresses, such as harsh weather. 

Global Climate Change

The earth's atmosphere is a delicate balance of naturally occurring gases that trap excessive heat from the sun. This greenhouse effect protects and maintains a stable temperature on the planet. Throughout time, humans have disturbed this natural balance by producing greenhouse gases, including carbon dioxide and methane. Thus, the earth's atmosphere is trapping more of the sun's heat, leading to the average temperature to rise. This phenomenon is known as “global warming.” Global warming has significant impacts on human health, agriculture, water resources, forests, wildlife, and coastal areas. 

Air pollution and its potential impacts on the environment are fully reviewed in our PE Environmental refresher course.

Sunday, 16 April 2017

Introduction to Basics of Boiler Components for Mechanical Engineers

The most important components of boilers include fuel oil systems, super heaters, and ash removal systems. As a mechanical engineer, it is extremely critical to understand the various components of boilers. Heat transfer is an important topic for undergraduate mechanical engineers preparing to take the FE Mechanical exam to understand. Heat transfer is thoroughly reviewed in our FE Mechanical exam review course. 

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Fuel Oil System

Oil-fired boilers may use a light grade oil, typically diesel, or a heavier grade residual oil that is often referred to as "Bunker Fuel." Light oils have a low viscosity and do not require pre-heating. They are pumped from the storage tank to the burner, which is equipped with an atomizing tip that sprays the oil into the furnace in the form of a fine mist. The mist mixes very rapidly with the combustion air, ensuring efficient and clean furnace operation. Heavy residual fuel oils are viscous and require pre-heating for proper atomization. The most commonly used residual fuels are typically more viscous. The temperature required to achieve optimal atomization may differ between fuels.

Super Heaters

Steam leaving the boiler is routed through the super heater element, which is located in a high-temperature zone of the furnace. The moisture quickly evaporates because the steam is no longer in contact with the water in the drum. The actual difference between the saturation temperature and the actual steam temperature is called the degree of superheat. Although superheating does add additional energy to the steam, the primary objective is to provide a margin of safety by ensuring that the steam does not immediately begin to condense prior to giving up its superheat energy component. Super heaters are commonly used in water tube boilers. The nature of the process determines whether a super heater is required; a super heater is not generally used unless there is a specific need.

Ash Removal 

Environmental legislation in most jurisdictions imposes strict constraints on particulate emissions. Therefore, removing entrained fly ash is usually a mandatory requirement on solid-fuel boilers. For large boilers, electrostatic precipitators, bag houses, and scrubbers are widely used. One of the most common methods employed on small to medium sized boilers is the multi-cyclone grit arrester; it has low capital costs and a degree of efficiency that will satisfy all but the most stringent requirements. Understanding boiler components and heat transfer mechanisms is critical for the FE Mechanical exam. Our FE Mechanical exam review course thoroughly covers the topics of heat exchangers, boiling, and condensation. 

Common Types of Boilers for Engineering Applications 

· Fire tube boilers: 

Fire tube boilers have the advantage of relatively low capital and operating costs. These types of boilers are predominantly used in industries and processes that have modest steam demands at low to medium pressure. Physical size constraints impose limits on operating pressure and because of their large mass, fire tube boilers are not well suited to large, rapid changes in steam loads. 

· Water Tube Boilers 

The water circulation through the tubes of a water tube boiler follows a defined path. This process ensures that a relatively small quantity of water will be rapidly distributed by heat, which results in an efficient operation. Water tube boilers can be brought up to working pressure much more quickly than fire tube equivalents.


Monday, 10 April 2017

Measuring Instruments and Their Performance Characteristics

Introduction

Measuring instruments are used to measure a quantity. When choosing an instrument, the static calibration and static performance of an instrument must be considered. Our PE Electrical exam review course thoroughly covers what to consider when selecting instruments for a given job.

The characteristics of measuring instruments can be classified into the following categories:

1)Static performance characteristics
2)Dynamic performance characteristics

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Static Calibration

Static calibration refers to the procedure where an input is constant or a variable is applied to an instrument. Instruments are manufactured based on the property of irreversibility or directionality. This implies that change in an input quantity will cause a corresponding change in the output. A calibration standard must be at least ten times more accurate than the instrument to be calibrated.

Static performance characteristics include the linearity performance of the instrument, static sensitivity of the instrument, repeatability of the same results, hysteresis resolution, and the readability of the results. 

Static performance characteristics influence data acquisition if the instruments are not properly calibrated prior to the measurement. Understanding quality control and quality assurance procedures for handling equipment is essential for the PE exam.

Linearity

If the relationship between the output and input can be expressed by the equation Q0= P + RQ1, where P and R are constants, then the instrument is considered linear. Linearity is never fully achieved in real-world situations, and the deviations from the ideal are referred to as linearity tolerances. For example, 3% independent linearity means that the output will remain within the values set by two parallel lines spaced ± 3% of the full-scale output from the idealized line. If the input-output relationship is not linear for an instrument, it may still be approximated to a linear form when it is used over a very restrictive range. 

Static Sensitivity

Static sensitivity can be defined as the slope of a calibration curve. 

Sensitivity = Q0/Q1

Sensitivity influences the input parameters of an instrument. The sensitivity factor can also be referred to as sensitivity drift or scale factor drift. 

Repeatability Error 

When an instrument is used to measure the same or an identical input many times and at different time intervals, the output is never the same; it deviates from the recorded values. This deviation from the ideal value is referred to as repeatability error.

Hysteresis-Threshold Resolution

When testing an instrument for repeatability, it is often noted that the input-out value does not coincide with the inputs, which are continuously ascending and descending values. This occurs because of hysteresis, which is caused by internal friction, sliding, external friction, and free play mechanisms. Hysteresis can be eliminated by taking readings corresponding to the ascending and descending values of the input and calculating their arithmetic mean.

Professional engineers who work with measurements and instrumentation should understand calibration procedures of various instruments for proper data acquisition.

Monday, 3 April 2017

Importance of Quality Control and Quality Assurance Procedures

Productivity and Quality Control Plan Implementation

In order to enhance client satisfaction during a construction project, the project must meet the expected quality. This expected quality can be ensured through quality assurance and quality control activities. The quality control process confirms that the project outcome meets the client’s standards. The quality assurance process checks the quality plan and quality control process to confirm that quality standards are implemented on the project site. To improve the quality construction of the project, understanding project requirements and standards is essential. This is usually done by a team outside of the project construction team, and the goal of this practice is to maintain quality standards, eliminate practices that are not appropriate and share best practices for quality assurance in the organization and with the project construction team. The project quality plan should be part of the project construction management plan. The quality control plan defines how quality should be handled throughout the duration of the project. Quality and safety are the main concerns for project completion. In large construction projects, management assigns an individual department for quality assurance and safety to ensure the standards of the project; in small projects, the project manager is responsible for quality assurance. Construction productivity and quality control procedures and testing methods are important for PE exam preparation


Project Quality Management Plan for Construction Projects

The success of any project has two key factors: one is the completion of the project on schedule as per the contract document and the quality of the project as per department standards. A failed project cannot lead to achieving business goals, and moreover, it leads to losses. Proper project planning is the first step for the success of the project. The plan describes the number of phases in the project and the list of construction activities to be carried out in each phase. Individual responsibility of each project phase, the duration of the project and the overall project budget are also included in the project plan. Generally, there are four steps in construction project management. The steps are planning, executing, monitoring and quality assurance. Each and every step of project management should contain a document within itself. These four steps help to increase productivity and quality as per the client’s requirements. The team should evaluate the overall project on a regular basis to validate the quality standards of the project. The responsibility of the project engineer is to ensure that quality control is implemented effectively. It is best to have professional engineer exam certified candidates in charge for better productivity and overall quality.

Disadvantages of Inappropriate Quality Control Procedures

Overlooking the quality control procedures of a project incurs additional expenses and project delays. Having to rework increases the maintenance and opportunity costs. Structural elements that are not built according to quality assurance standards have the potential to collapse at any time, which could lead to injuries and death. Professional engineers ensure the quality of the project the first time around. Project quantity takeoffs and scheduling costs should be recapped through a PE exam review course. The project team should maintain good communication with the client. When the project is completed, the essential support and technical arrangements should be given to the client. After completing the project, the project document should be finalized, and the final report of the project should be prepared. If the organization follows a quality management process, completing new projects is not a major ordeal.

Monday, 27 March 2017

Water Desalination Methods for Water Resource Engineers

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. 

Water Desalination Methods

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.

Desalination process

Tuesday, 21 March 2017

Structural Engineering Standards for Historical Buildings’ Preservation and Maintenance

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. 

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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.

Thursday, 16 March 2017

Stormwater Management Practices for Healthy Environmental Engineering Activities

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.

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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.