Disaster And Failure Final

An "off hook" condition is primarily used to signal the phone company switch to expect a phone number to be dialed. When a phone is off the hook, it means that the receiver has been lifted or the call button has been pressed, indicating the intention to make a call. This signal is sent to the phone company switch, which prepares to receive the dialed digits and connect the call accordingly.

The correct answer is "lattice works used to relieve the deck of tension and compression forces". This is because a truss is a structural framework made of triangular shapes that are interconnected to form a rigid structure. The triangular shapes in a truss help distribute the forces of tension and compression throughout the structure, making it more stable and able to bear heavy loads.

A cantilever bridge is best suited for carrying heavy loads such as trains. This type of bridge has a rigid structure with a horizontal beam supported at only one end, allowing it to handle heavy weights without collapsing. The weight of the load is distributed evenly across the bridge, making it ideal for carrying heavy and concentrated loads. Cantilever bridges are commonly used in railway infrastructure due to their strength and ability to support heavy train traffic.

The given statement, "The resulting bridge inspection program continues to ensure safe bridge today," is not true. The Silver Bridge Disaster in 1967 was indeed a suspension bridge and it was aggravated by heavy Christmas traffic. However, the disaster did not result in the implementation of a bridge inspection program that continues to ensure safe bridges today.

The first USA EV (space walk) occurred during the Gemini program. The Gemini program was a NASA spaceflight program that ran from 1961 to 1966. It was designed to develop and test the skills and techniques necessary for the Apollo program, which aimed to land astronauts on the Moon. The first American spacewalk took place during the Gemini IV mission in 1965 when astronaut Ed White exited the spacecraft and floated freely in space for approximately 20 minutes.

LEO, in the context of unit 10 notes, refers to low earth orbit. This term is commonly used in the field of space exploration and refers to a circular orbit around the Earth at a relatively low altitude. Satellites and spacecraft are often placed in low earth orbit due to its proximity to Earth and its ability to provide better communication and imaging capabilities.

The Challenger disaster, which occurred in 1986, was attributed to the lack of O-ring flexibility in cold weather. The O-rings, which were used to seal the joints of the solid rocket boosters, failed to function properly due to the low temperatures on the day of the launch. This led to the ignition of the external fuel tanks and the subsequent explosion of the shuttle. The incident highlighted the importance of thorough testing and consideration of environmental conditions in the design and operation of space vehicles.

The given answer states that the altitude of the International Space Station (ISS) is not cited as a problem. This means that the altitude being too high is not considered a drawback or issue with the ISS. However, the question does not provide any context or information about the problems with the ISS, so it is difficult to determine why the altitude is not considered a problem.

The correct answer is "tired and overworked staff". The other three options are factors that are listed in the class notes as contributing to the Three Mile Island disaster. The cross connection of service and control lines, the control valves being left off during maintenance, and the inability to directly measure reactor water level are all mentioned as factors in the disaster. However, there is no mention of tired and overworked staff as a contributing factor in the class notes.

Transformers are electrical devices that are used to change the voltage levels of alternating current (AC) electricity. They consist of two or more coils of wire wrapped around a magnetic core. By varying the number of turns in each coil, transformers can step up or step down the voltage of the AC power. This is important in electrical power transmission and distribution systems as it allows for efficient transfer of electricity over long distances and enables the use of different voltage levels for various applications. Therefore, transformers are used to convert AC voltage levels.

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Magnetic Resonance Imaging (MRI) is a diagnostic technique that uses a strong magnetic field and radio waves to generate detailed images of the inside of the body. It does not use ionizing radiation such as X-rays or radioactive materials. MRI is commonly used to diagnose various medical conditions and is considered a safe and non-invasive imaging modality.

The correct answer is hardware, software, and standards. The internet can be viewed in terms of these three items because hardware refers to the physical components such as servers, routers, and cables that make up the network infrastructure. Software refers to the programs and applications that enable communication and data transfer over the internet. Standards, on the other hand, are the protocols and rules that govern how data is transmitted and received. Together, these three elements form the foundation of the internet and allow for its functioning.

The number and quality of graphics on a website may contribute to its visual appeal, but it is not a reliable indicator of the quality of information. The presence of high-quality graphics does not guarantee that the information provided is accurate or credible. The credibility of information is better assessed through factors such as the use of peer reviews, the domain type, and the interests of the information author.

The correct answer is stone, steel, concrete, wood. This is because the answer correctly arranges the materials from the poorest to the best in terms of relative ease of use. Stone is the poorest material to work with due to its hardness and difficulty in shaping. Steel is easier to work with compared to stone but still requires specialized tools and techniques. Concrete is easier to handle and shape compared to steel. Wood is the best material to work with as it is relatively easy to shape and manipulate.

The correct answer for this question is that the construction material was too light. This means that the materials used to build the Tacoma Narrows Bridge were not strong or sturdy enough, leading to its collapse.

If the burnout velocity of an earth bound object exceeds its escape velocity, it means that the object has achieved enough velocity to overcome the gravitational pull of the Earth. As a result, the object will be able to escape the Earth's gravity and continue moving away from it. This implies that the object will not be affected by the gravitational force of the Earth and will not be pulled back towards it. Therefore, the correct answer is "escape the pull of earth's gravity".

The given answer, "poorly trained scientists and engineers," is not considered a current problem with the US space program. This means that the US space program does not suffer from a lack of skilled and knowledgeable professionals in the field. The other options listed, such as the lack of shuttle flights after 2010, changing policies and priorities, and the lack of ground-based support facilities, are all considered current problems with the US space program.

An FBR (Fast Breeder Reactor) can run on the spent fuels of other reactors. Fast breeder reactors use fast neutrons to convert non-fissile isotopes into fissile isotopes, allowing them to generate more fuel than they consume. This means that they can utilize the spent fuels from other reactors, which contain a significant amount of unused fissile material, and convert it into usable fuel. This makes FBRs an efficient and sustainable option for nuclear energy production.

The aftermath of the Three Mile Island incident did not result in the failings of containment structures being made apparent. The incident itself did expose flaws in the reactor's design and operation, but it did not specifically highlight any deficiencies in the containment structures. The other consequences mentioned, such as reactor 1 being shut down for 6 years, the cancellation of new reactor orders, and the public's decline in faith in nuclear power, are all well-documented outcomes of the Three Mile Island incident.

Lighter than air vehicles, such as hot air balloons or airships, are slower compared to airplanes due to their design and propulsion systems. However, they can achieve longer ranges as they can stay in the air for extended periods of time without needing to refuel. These vehicles can be considered dangerous due to their vulnerability to changing weather conditions and lack of maneuverability, which can pose risks during flight. Therefore, the correct answer is "slow, long range, and dangerous".

Gamma-rays are a type of high-energy electromagnetic radiation. They have the shortest wavelength and highest frequency in the electromagnetic spectrum. Gamma-rays are produced by nuclear reactions and radioactive decay. They are commonly used in medical imaging and cancer treatment, as well as in scientific research and industrial applications.

The lack of inspection during construction as well as after the bridge went into service was one of the major problems leading to the Tay Bridge Disaster of 1879. This suggests that there was a failure to properly assess the construction process and identify any potential issues or weaknesses in the bridge. Additionally, the lack of inspection after the bridge was completed and put into service indicates a lack of ongoing maintenance and monitoring, which could have helped identify and address any structural problems.

Unmanned space programs face the problem of resistance to the idea by the military and others. This suggests that there are individuals or groups who are opposed to the concept of unmanned space programs, possibly due to various reasons such as concerns about the effectiveness or safety of unmanned missions. This resistance can pose challenges and obstacles for the development and implementation of unmanned space programs.

The problem associated with the Chernobyl disaster was the lack of a containment building. A containment building is a structure that is designed to contain any potential releases of radioactive materials in the event of a nuclear accident. In the case of Chernobyl, the reactor exploded and released a significant amount of radioactive material into the environment because there was no containment building to prevent the spread of the radiation. This lack of containment greatly contributed to the severity of the disaster and the widespread contamination that followed.

The Linac (linear accelerator) in the Therac-25 generates beta-rays and x-rays. Alpha-rays are not generated because they are heavy particles that do not penetrate the body easily. Gamma-rays are also not generated because the Linac produces high-energy electrons that are used to generate x-rays. Therefore, the correct answer is beta-rays and x-rays.

Alpha-rays are a type of radiation that consists of energetic charged particles. These particles are typically helium nuclei, consisting of two protons and two neutrons. They have a positive charge and are emitted during radioactive decay. Alpha-rays have a relatively low penetrating power and can be stopped by a sheet of paper or a few centimeters of air. Therefore, they are considered to be less harmful compared to other types of radiation such as gamma-rays or beta-rays.

Beta-rays are an example of energetic charged particles. Beta radiation consists of high-energy electrons or positrons emitted from the nucleus of an atom during radioactive decay. These particles have a charge and are highly energetic, making them capable of penetrating matter and causing ionization. Therefore, the correct answer is "energetic charged particles."

Fault tolerant computing involves increasing the reliability using duplicate computers. This means that in a fault tolerant system, multiple identical computers are used to perform the same task simultaneously. If one computer fails, the others can continue the operation without any interruption, ensuring that the system remains reliable and available. By duplicating the computers, fault tolerant computing aims to minimize the impact of hardware or software failures and provide continuous operation.

A land-line home phone connects to an "end office" via a local loop. The local loop is the physical connection between the telephone exchange, or end office, and the customer's premises. It is typically a twisted pair copper wire that carries the telephone signal from the exchange to the customer's home. This connection allows the customer to make and receive calls using their land-line phone.

A ringer and an amplifier are both considered parts of a typical telephone. A ringer is responsible for producing the sound or ringing tone when there is an incoming call, while an amplifier is used to increase the volume of the audio signal transmitted through the telephone. Both components play essential roles in the functioning of a telephone system.

The use of substandard quality materials was NOT a major factor in the Quebec bridge construction disaster. This suggests that the materials used in the construction were not the main cause of the disaster. Other factors such as attempts to cut construction costs, lack of on-site experience personnel, and failure to test design changes likely played a more significant role in the disaster.

Systematic error in a set of measurements is usually the result of some uniform problems in the data collection. This means that there are consistent and repeatable issues in the way the data is being collected, which leads to a consistent bias in the measurements. It could be due to faulty equipment, incorrect calibration, or a flaw in the experimental setup that affects all the measurements in a similar way. This type of error can be identified and corrected by addressing the specific problems in the data collection process.

In a Pressurized Water Reactor (PWR), the water passing through the reactor is kept at a high pressure to prevent it from boiling. This high-pressure water then heats a second loop of water, known as the primary coolant, which is kept separate from the reactor. The primary coolant transfers its heat to a secondary loop of water, which creates steam for running the turbine. This design ensures that the radioactive materials in the reactor core remain contained and isolated from the steam that powers the turbine.

The class notes mention various problems associated with AC power transmission, such as danger to humans, limited space for new power lines, and maintaining load balance and phase on generators. However, conversion to DC power is not listed as a problem.

Phishing refers to one person acting like another to get information. This is a type of cyber attack where the attacker impersonates a trusted entity, such as a bank or a social media platform, in order to trick individuals into revealing sensitive information like passwords, credit card numbers, or personal data. The attacker often uses deceptive emails, messages, or websites that appear legitimate to deceive the victim into providing their information. This form of social engineering relies on exploiting human psychology and trust to gain unauthorized access to personal or financial information.

The author does not mention dead links as a problem with information obtained from the web.

The correct answer is "transferring web pages" because HTTP (Hypertext Transfer Protocol) is a protocol used for transmitting and receiving information on the World Wide Web. It is specifically designed for transferring hypertext, which includes web pages, from a web server to a web browser. HTTP allows users to request and receive web pages, as well as other resources such as images and videos, over the internet. It is the foundation of communication on the web and ensures the seamless transfer of web content between servers and clients.

Connecting computers together over a network is called distributed computing. In distributed computing, multiple computers are connected and work together to solve a problem or perform a task. This allows for the sharing of resources and processing power, leading to increased efficiency and scalability. Tightly coupled computing refers to a system where multiple computers are closely interconnected and rely heavily on each other, while loosely coupled computing refers to a system where computers are more independent and can function individually. Parallel computing involves dividing a task into smaller subtasks that are processed simultaneously by multiple computers, while distributed computing involves dividing a task into smaller subtasks that are processed by different computers connected over a network.

Bell Telephone equipment has been historically noted for its high quality and little innovation. This means that while the equipment produced by Bell Telephone was of excellent quality, there was not much innovation or groundbreaking advancements in their products. This suggests that Bell Telephone focused more on maintaining a high standard of quality rather than introducing new and innovative features or technologies.

The Therac-25 had a problem with using under tested computer based systems. This means that the computer systems used in the Therac-25 were not adequately tested before being implemented. This could have led to software bugs or errors that caused the machine to malfunction or deliver incorrect radiation doses to patients. The lack of proper testing and quality control in the computer systems used in the Therac-25 was a significant issue that contributed to its problems and safety concerns.

During the period from the 1920's to the mid-1960's, the US phone system was characterized by mechanical intensive operation. This means that the system relied heavily on mechanical components and processes for its functioning. This could include manual switchboards, rotary dial telephones, and other mechanical systems that were used to connect calls and transmit signals. This era predates the widespread use of electronic technology in the telecommunications industry.

The correct order of the US space programs is Mercury, Gemini, and Apollo. The Mercury program was the first human spaceflight program in the United States, followed by the Gemini program, which aimed to develop the skills and techniques necessary for the Apollo program. The Apollo program was responsible for landing the first humans on the moon.

In a boiling water reactor (BWR), water passing through the reactor is allowed to boil, creating steam that is used to run the turbine. This is in contrast to a pressurized water reactor (PWR), where the water remains in a liquid state and transfers heat to a separate secondary loop to produce steam. The high-pressure steam produced in a BWR directly drives the turbine, making it a simpler and more efficient design.

The given correct answer for this question is "frequent engine failure." This means that one of the problems with the De Havilland Comet 1 passenger jet was not related to frequent engine failure. However, it is important to note that the other options mentioned in the question, such as the thin fuselage skin, use of square windows, and loss of wing lift when pulled up too fast, were indeed problems with the De Havilland Comet 1. These issues ultimately led to a series of accidents and the grounding of the aircraft until improvements were made.

Cracking into online databases is a technique used to obtain private information. This involves unauthorized access to databases, where sensitive data is stored. By gaining entry, individuals can extract personal information such as financial details, passwords, and other confidential data. This method is often employed by hackers and cybercriminals to exploit security vulnerabilities and breach the privacy of individuals or organizations.

The AT&T failure of January 15, 1990, was caused by an error in the software used to protect the system. This suggests that there was a flaw or mistake in the software that was supposed to ensure the system's security and stability. This error could have led to the failure and disruption of the AT&T network on that day.

The Challenger shuttle disaster was the worst US space program related accident in terms of loss of life. On January 28, 1986, the Space Shuttle Challenger broke apart just 73 seconds after liftoff, resulting in the death of all seven crew members on board. This tragedy shocked the nation and led to a suspension of the Space Shuttle program for almost three years. The loss of the Challenger crew highlighted the risks and complexities involved in space exploration and served as a catalyst for improvements in safety measures within the US space program.

The major problem facing the ISS has been changing policies and requirements. This implies that the ISS has encountered difficulties due to constantly evolving rules and demands. It suggests that the project has faced challenges in adapting to new policies and meeting changing requirements, which could have caused disruptions or delays in its operations.

Out-of-band switching refers to the use of special lines for control signals. This means that instead of using the regular communication channels, separate lines are dedicated solely for transmitting control signals. This allows for more efficient and reliable control of the switching process, as it reduces the risk of interference or congestion that may occur on the main communication lines. By using special lines, the control signals can be transmitted separately and independently from the regular data signals, ensuring smooth and uninterrupted operation of the switching system.