Security engineering

Security engineering is the field of engineering dealing in developing detailed engineering designs for security systems and for security of spaces. It is similar to systems engineering in that its motivation is to make a system meet requirements, but with the added dimension of enforcing a security policy. It has existed as an informal field for centuries, in the fields of locksmithing and security printing.

Security engineering involves a wide variety of aspects; ranging from social science (namly Human behaviour pattern understanding), psychology, economics, Landscape design, physics, chemistry and mathematics.

Some of the techniques used, such as fault tree analysis, are derived from safety engineering. Other techniques such as cryptography were previously restricted to military applications. One of the pioneers of security engineering as a formal field of study is Ross Anderson.

Paper engineering

Paper engineering or Paper Science is an interdisciplinary branch of engineering that deals with the application of physical science (e.g. chemistry and physics) with mathematics to the process of converting renewable bio-resources into useful and valuable products. Similar to chemical engineering in many aspects, the field employs the common principles of process engineering to the manufacture of pulp, paper and other biomaterials.

Paper engineering encompasses the design and analysis of the various unit operations employed in the manufacture of paper; addressing the preparation of its raw materials from trees or other natural resources via a pulping process, chemical and mechanical pretreatment of these recovered biopolymer (e.g. principally, although not solely ,cellulose-based) fibers in a fluid suspension, the high-speed forming and initial dewatering of a non-woven web, the development of bulk sheet properties via control of energy and mass transfer operations, as well as post-treatment of the sheet with coating, calendering, and other chemical and mechanical processes.

Nuclear reaction

The reaction equation
In the symbolic figure shown above, 6Li and deuterium react to form the intermediate nucleus 8Be which then decays immediately into two alpha particles.

A nuclear reaction can be written in terms of a formula just like a chemical reaction. Nuclear decays can be written in a similar way, but with only one nucleus on the left side.

Every particle partaking in the reaction is written with its chemical symbol, with the mass number at the upper left and the atomic number at the lower left. The neutron is written "n"; the proton can be written "1H" or "p".

Shorter notation
Many common particles are often abbreviated, the nucleus 4He, e.g., the alpha particle, is written with the Greek letter "α". Deuterons (heavy hydrogen nuclei 2H) are called "d". Also, the atomic numbers can be omitted after verifying the equation, since they are uniquely given by the chemical symbols. In many practical cases, a light particle (the "projectile") hits a comparatively heavy nucleus (the "target"), a light particle (the "ejectile") is emitted, and another nucleus remains. In these cases, the reaction can be written in a simplified way:

Target nucleus (Projectile, Ejectile) Final nucleus
Energy conservation
Kinetic energy may be released during the course of a reaction (exothermic reaction) or kinetic energy may have to be supplied for the reaction to take place (endothermic reaction). This can be calculated by reference to a table of very accurate particle rest masses (see http://physics.nist.gov/PhysRefData/Compositions/index.html), as follows. According to the reference tables, the 63Li nucleus has a relative atomic mass of 6.015 atomic mass units (abbreviated u), the deuteron has 2.014 u, and the helium-4 nucleus has 4.0026 u Thus:

Total rest mass on left side = 6.015 + 2.014 = 8.029 u
Total rest mass on right side = 2 × 4.0026 = 8.0052 u
Missing rest mass = 8.029 - 8.0052 = 0.0238 atomic mass units.
In a nuclear reaction, the total (relativistic) energy is conserved. The "missing" rest mass must therefore reappear as kinetic energy released in the reaction; its source is the nuclear binding energy. Using Einstein's mass-energy equivalence formula E = mc², the amount of energy released can be determined. We first need the energy equivalent of one atomic mass unit:

1 u c2 = (1.66054 × 10-27 kg) × (2.99792 × 108 m/s)2
= 1.49242 × 10-10 kg (m/s)2 = 1.49242 × 10-10 J (Joule)
× (1 MeV / 1.60218 × 10-13 J)
= 931.49 MeV,
so 1 u c2 = 931.49 MeV.
Hence, the energy released is 0.0238 × 931 MeV = 22.4 MeV.

Expressed differently: the mass is reduced by 0.3 %, corresponding to 0.3 % of 90 PJ/kg is 300 TJ/kg.

This is a large amount of energy for a nuclear reaction; the amount is so high because the binding energy per nucleon of the helium-4 nucleus is unusually high, because the He-4 nucleus is doubly magic. (The He-4 nucleus is unusually stable and tightly-bound for the same reason that the helium atom is inert: each pair of protons and neutrons in He-4 occupies a filled 1s nuclear orbital in the same way that the pair of electrons in the helium atom occupy a filled 1s electron orbital). Consequently, alpha particles appear frequently on the right hand side of nuclear reactions.

The energy released in a nuclear reaction can appear mainly in one of three ways:

kinetic energy of the product particles
emission of very high energy photons, called gamma rays
some energy may remain in the nucleus, as a metastable energy level.
When the product nucleus is metastable, this is indicated by placing an asterisk ("*") next to its atomic number. This energy is eventually released through nuclear decay.

A small amount of energy may also emerge in the form of X-rays. Generally, the product nucleus has a different atomic number, and thus the configuration of its electron shells is wrong. As the electrons rearrange themselves and drop to lower energy levels, internal transition X-rays (X-rays with precisely defined emission lines) may be emitted.

Q-value and energy balance
In writing down the reaction equation, in a way analogous to a chemical equation, one may in addition give the reaction energy on the right side:

Target nucleus + projectile -> Final nucleus + ejectile + Q.
For the particular case discussed above, the reaction energy has already been calculated as Q = 22.4 MeV. Hence:

63Li + 21H → 42He + 42He + 22.4 MeV
The reaction energy (the "Q-value") is positive for exothermal reactions and negative for endothermal reactions. On the one hand, it is the difference between the sums of kinetic energies on the final side and on the initial side. But on the other hand, it is also the difference between the nuclear rest masses on the initial side and on the final side (in this way, we have calculated the Q-value above).

Neutrons versus ions
In the initial collision which begins the reaction, the particles must approach closely enough so that the short range strong force can affect them. As most common nuclear particles are positively charged, this means they must overcome considerable electrostatic repulsion before the reaction can begin. Even if the target nucleus is part of a neutral atom, the other particle must penetrate well beyond the electron cloud and closely approach the nucleus, which is positively charged. Thus, such particles must be first accelerated to high energy, for example by:

particle accelerators
nuclear decay (alpha particles are the main type of interest here, since beta and gamma rays are rarely involved in nuclear reactions)
very high temperatures, on the order of millions of degrees, producing thermonuclear reactions
cosmic rays
Also, since the force of repulsion is proportional to the product of the two charges, reactions between heavy nuclei are rarer, and require higher initiating energy, than those between a heavy and light nucleus; while reactions between two light nuclei are commoner still.

Neutrons, on the other hand, have no electric charge to cause repulsion, and are able to effect a nuclear reaction at very low energies. In fact at extremely low particle energies (corresponding, say, to thermal equilibrium at room temperature), the neutron's de Broglie wavelength is greatly increased, possibly greatly increasing its capture cross section, at energies close to resonances of the nuclei involved. Thus low energy neutrons may be even more reactive than high energy neutrons.

Notable types
While the number of possible nuclear reactions is immense, there are several types which are more common, or otherwise notable. Some examples include:

Fusion reactions - two light nuclei join to form a heavier one, with additional particles (usually protons or neutrons) thrown off to conserve momentum.
Fission reactions - a very heavy nucleus, spontaneously or after absorbing additional light particles (usually neutrons), splits into two or sometimes three pieces. (α decay is not usually called fission.)
Spallation - a nucleus is hit by a particle with sufficient energy and momentum to knock out several small fragments or, smash it into many fragments.
Induced gamma emission belongs to a class in which only photons were involved in creating and destroying states of nuclear excitation.

Ocean engineering

Work of ocean engineers
The Society of Naval Architects and Marine Engineers describes the work of ocean engineers as follows:

Ocean engineers study the ocean environment to determine its effects on ships and other marine vehicles and structures. Ocean engineers may design and operate stationary ocean platforms, or manned or remote-operated sub-surface vehicles used for deep sea exploration.
There are six main areas of specialization in Ocean Engineering. Each has received substantial research support, and has faculty who are committed to doing research in these areas. Brief descriptions are given below.

Ocean instrumentation and seafloor mapping deals with the development and use of new and improved instruments for monitoring ocean processes, and the subsequent analysis of the data. Areas of current research interest include: design, development, and the operation of sensors, software, systems, and vehicles for underwater acoustic and optical measurements with associated navigation; development of advanced systems for mapping and visualizing the ocean floor; implementation of real-time, geographic information systems for survey data acquisition and processing, and the design, construction, and testing of a ship motion simulator for the testing of vessel attitude and motion sensors for correcting shipboard instruments.

Underwater acoustics and data analysis deals with the study of sound and vibration in the ocean and seabed, and the associated analysis of both deterministic and random data. Sequences of courses in both acoustics and data analysis are offered. Past research topics have included: the design and development of special purpose transducers and arrays, deep-water sediment surveying and seismic bottom penetration classification studies using advanced signal processing methods. Recent research has focused on: acoustic transient radiation and scattering from complex fluid loaded structures, shallow water sound propagation, wave propagation in structures, localized space/time wavefields, and active noise and vibration control. Adaptive wavelet and other advanced signal processing methods are being used to investigate a wide range of problems in structural acoustics and wave propagation in general.

Marine hydrodynamics and water-wave mechanics involves studies of ocean and nearshore environments and the interaction of bodies with these flow and wave fields. Problems of particular interest are nonlinear wave dynamics and forces on submerged and emergent breakwaters, wave shoaling and breaking on beaches, fluid-structure interaction, wave forces generated by forced body motion, and the drag of marine vehicles.

Coastal and nearshore modeling deals with the physical and numerical modeling of coastal and nearshore processes. Models are developed, applied, and verified with field and laboratory measurements. Wind-wave generation, wave refraction, diffraction, shoaling and breaking, surf-zone dynamics and littoral transport, pollutant and oil spill transport, harbor oscillations, tidal and wind- driven circulation in coastal and estuarine waters, and tidal inlet and barrier-island-related problems are studied. Finite difference, finite element, and boundary elements numerical methods are used.

Marine geomechanics is directed toward development of a broad background in the theory and practice of geotechnics in the ocean environment. The research includes experimental and modeling studies to understand and predict properties and behavior of the seabed. Recent sponsored research has included studies on: sediment stress-strain and strength properties; anchor systems; seabed disposal of dredge materials; cable and pipeline siting and burial; instrument development for sediment sampling and in-situ testing; seabed processes including sediment erosion, slope stability, creep deformations, and dynamic processes; foundations for offshore and coastal structures; ice-sediment interactions; dynamic soil properties; and microstructure of sediments. Current research projects, sponsored by four different agencies, focus on downslope processes of slope and rise sediments, coastal benthic boundary- layer processes and properties, ocean disposal of contaminated dredged materials, and geoacoustic properties of the seabed related to mine detection. Modern geotechnical laboratory facilities have up-to-date and specially designed equipment for research on marine sediments.

Coastal and offshore structures is the study of nearshore piers, breakwaters, groins, piles, and sewer outfalls as well as common offshore structures such as petroleum drilling and operating platforms. Breakwaters are important for beach and harbor protection against waves and storms and for their ability to minimize oscillation of moored vessels. Groins are used for limiting shoreline erosion, and jetties for the stabilization of inlets and estuary entrances. The offshore structures today are large, generally very complex, and extremely expensive, and most often involve safety considerations for a hundred or more humans. Present research focuses on modeling the response of offshore structures to wave loading and on representing the statistical properties of random wave fields more accurately.

Additional areas of study include: remote sensing and corrosion and composite materials. Corrosion and corrosion control are topics that permeate most of the research activities in the ocean engineering program. In addition, specific thesis topics on corrosion as an important chemical process in the marine environment are receiving increasing attention in the program.

Optical engineering

Optical engineering is the field of study that focuses on applications of optics.

Optical engineers design components of optical instruments such as lenses, microscopes, telescopes, and other equipment that utilize the properties of light. Other devices include optical sensors and measurement systems, lasers, fiber optic communication systems, optical disc systems (e.g. CD, DVD), etc.

Since optical engineers want to design and build devices that make light do something useful, they must understand and apply the science of optics in substantial detail, in order to know what is physically possible to achieve (physics and chemistry). However, they also must know what is practical in terms of available technology, materials, costs, design methods, etc. As with other fields of engineering, computers are important to many (perhaps most) optical engineers. They are used with instruments, for simulation, in design, and for many other applications. Engineers often use general computer tools such as spreadsheets and programming languages, and they make frequent use of specialized optical software designed specifically for their field.

Optical engineering metrology uses optical methods to measure micro-vibrations with instruments like the laser speckle interferometer or to measure the properties of the various masses with instruments measuring refraction.

Nuclear engineering

Nuclear engineering is the practical application of the atomic nucleus gleaned from principles of nuclear physics and the interaction and maintenance of nuclear fission systems and components, specifically, nuclear reactors, nuclear power plants and/or nuclear weapons. The field can also include the study of nuclear fusion, medical applications of radiation, nuclear safety, heat transport, nuclear fuels technology, nuclear proliferation, and the effect of radioactive waste or radioactivity in the environment.

Undergraduate coursework
Undergraduate coursework should begin with a foundation in mechanics and dynamics of particle motion, thermodynamics, introductory computer programming, college level physics and chemistry, and a rigorous training in mathematics through differential equations.

Midway through undergraduate training a nuclear engineer must choose a specialization within his or her field that he or she will further study. Further coursework in a nuclear engineering program includes but is not limited to fluid mechanics, reactor physics, quantum mechanics, thermal hydraulics, linear circuits, radiation effects, and neutron transport.

Specialization in fission includes the study of nuclear reactors, fission systems, and nuclear power plants, the primary teachings deal with neutronics and thermal-hydraulics for nuclear generated electricity. A firm foundation in thermodynamics and fluid mechanics in addition to hydrodynamics is a must.

Specialization in nuclear fusion includes electrodynamics and plasmas. This area is very much research oriented and training often terminates with a graduate level degree.

Specialization in nuclear medicine includes courses dealing with doses and absorption of radiation in bodily tissues. Those who get competency in this area usually move into the medical field. Many nuclear engineers in this specialization go on to become board licensed medical physicists or go to medical school and become a radiation oncologist. Research is also a common choice for graduates.

Naval Nuclear Power School
The U.S. Navy runs a program called Naval Nuclear Power School to train both officers and enlisted sailors for nuclear plant operation. While some officers have undergraduate backgrounds in nuclear engineering, those with degrees in physics, mathematics, or other engineering disciples are also accepted, whereas most of the enlisted students hold no college degrees at all. Despite this, they are prepared, through a rigorous training program (lasting between 65 weeks for Machinist's Mates and eighteen months for Electronics Technicians and Electrician's Mates), to operate the nuclear and steam plants aboard the navy's submarines and aircraft carriers. This training carries Department of Energy certification, and many sailors choose to work at civilian power plants after their six-year obligations are completed.

Nuclear Fission
Nuclear fission is the disintegration of a fissionable atom nucleus into two different elements nucleus. An approximate number of ~2.4 neutrons are scattered around per fission. There are two types of nuclear fission. 1-Fast Fission 2-Thermal fission

Generally, thermal fission is used in commercial reactors,if we disregard the Fast Breeder Type of Nuclear Reactors.

The United States gets about 20% of its electricity from nuclear power. This is a massive industry and keeping the supply of nuclear engineers plentiful will ensure its stability. Nuclear engineers in this field generally work, directly or indirectly, in the nuclear power industry or for government labs. Current research in industry is directed at producing economical, proliferation resistant reactor designs with passive safety features. Although government labs research the same areas as industry, they also study a myriad of other issues such as: nuclear fuels and nuclear fuel cycles, advanced reactor designs, and nuclear weapon design and maintenance. A principal pipeline for trained personnel for US reactor facilities is the Navy Nuclear Power Program.

Nuclear Fusion and Plasma Physics
Research areas include high-temperature, radiation-resistant materials, and plasma dynamics. Internationally, research is currently directed at building a prototype tokamak called ITER. The research at ITER will primarily focus on instabilities and diverter design refinement. Researchers in the USA are also building an inertial confinement experiment called the National Ignition Facility or NIF. NIF will be used to refine neutron transport calculations for the US stockpile stewardship initiative.

Nuclear Medicine and Medical Physics
An important field is nuclear medicine. From x-ray machines to MRI to PET,among many others, nuclear medicine provides most of modern medicine's diagnostic capability along with providing many treatment options.

Nuclear Materials and Nuclear Fuels
Nuclear materials research focuses on two main subject areas, nuclear fuels and irradiation-induced modification of materials. Improvement of nuclear fuels is crucial for obtaining increased efficiency from nuclear reactors. Irradiation effects studies have many purposes, from studying structural changes to reactor components to studying nano-modification of metals and semiconductors using ion-beams or particle accelerators.

Radiation Measurements and Imaging
Nuclear engineers and radiological scientists are interested in the development of more advanced ionizing radiation measurement and detection systems, and using these to improve imaging technologies. This includes detector design, fabrication and analysis, measurements of fundamental atomic and nuclear parameters, and radiation imaging systems, among other things.

Naval architecture

Naval architecture is an engineering discipline dealing with the design, construction and repair of marine vehicles.

Due to the complexity associated with operating in a marine environment naval architecture is by necessity a co-operative effort between groups of technically skilled individuals that are specialists in particular fields, often co-ordinated by a lead naval architect. This inherent complexity also means that the analytical tools available are much less evolved than those for designing aircraft, cars and even space craft. This is due primarily to the paucity of data on the environment the marine vehicle is required to work in and the complexity of the interaction of waves and wind on a marine structure.

The areas of expertise filled by naval architects are typically:
Hydrostatics (ex: trim & stability)
Hydrodynamics (ex: resistance and powering, seakeeping, manoeuvring)
Arrangements (ex: concept design, volume & access)
Structures (ex: global strength, seaway responses)

The art of naval architecture
Venetian gondolaIn the past, naval architecture has been more art than science. The suitability of a vessel's shape was traditionally judged by looking at a half-model of a vessel or a prototype. Ungainly shapes or abrupt transitions were frowned on as being flawed. This included, rigging, deck arrangements, and even fixtures. Subjective descriptors such as ungainly, full, and fine were used as a substitute for the more precise terms used today. A vessel was, and still is described as having a ‘fair’ shape. The term ‘fair’ is meant to denote not only a smooth transition from front to back but also a shape that was ‘right.’ Determining what ‘right’ is in a particular situation in the absence of definitive supporting analysis encompasses the art of naval architecture to this day.

The science of naval architecture
Hull FormLow-cost digital computers, dedicated software combined with extensive research to correlate full-scale, towing tank and analytical data has increased the ability of a naval architect to more accurately predict the performance of a marine vehicle to a much higher level of accuracy than previously. These tools are used for static stability (intact and damaged), dynamic stability, resistance, powering, hull development, structural analysis, etc. Curiously, analytical tools (such as Computational Fluid Dynamics) are still having difficulty in predicting with absolute certainty the response of a floating body in a random sea. The challenge is being addressed by universities, towing tanks, etc. throughout the world. Data is regularly shared in International conferences sponsored by RINA, Society of Naval Architects and Marine Engineers (SNAME) and others.

The naval architect
A naval architect is a professional engineer who is responsible for the design, construction, and/or repair of ships, boats, other marine vessels, and offshore structures, both commecial and military, including:

Merchant Ships - oil/gas tankers, cargo ships, bulk carrier, container ships
Passenger/vehicle ferries, cruise ships
Warships - frigates, destroyers, aircraft carriers, amphibious ships, etc.
Submarines and underwater vehicles
Icebreakers
Offshore drilling platforms, semi-submersibles
High Speed Craft - hovercraft, multi-hull ships, hydrofoil craft, etc.
Workboats - fishing boat, platform supply vessel, tug boat, pilot vessels, rescue craft, etc.
Yachts, power boats, and other recreational craft
Some of these vessels are amongst the largest and most complex and highly valued movable structures produced by mankind. They are the most efficient method of transporting the world's raw materials and products known to man. Without them our society could not exist as it currently does.

Modern engineering on this scale is essentially a team activity conducted by specialists in their respective fields and disciplines. However, it is the naval architects who often integrate their activities and take ultimate responsibility for the overall project. This demanding leadership role requires managerial qualities and ability to bring together the often-conflicting demands of the various design constraints to produce a product, which is "fit for the purpose."

In addition to this vital leadership role, a naval architect also has a specialist function in insuring that a safe, economic, and seaworthy design is produced.

To undertake all these tasks, a naval architect must have an understanding of many branches of engineering and must be in the forefront of high technology areas such as vessel arrangements, hydrodynamics, stability, and structures. He or she must be able to effectively utilize the services provided by scientists, lawyers, accountants, and business people of many kinds.

Naval architects typically work for shipyards, ship owners, design firms, equipment manufacturers, regulatory bodies, navies, and governments.