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Topic Review
Wave-Structure-Seabed Interactions and Scour
Sediment transport has been the subject of extensive research over recent decades, particularly wave–structure interactions and, more importantly, their effects on the seabed. It includes mechanical models, analytical solutions of wave–structure–seabed interactions, and their verification with numerical models and experimental tests. Experimentally, both field and laboratory measurements focus on the structure foundation. Moreover, given the great progress in numerical modelling in the last decade, there is a need to put into context and focus the most widely used numerical approaches for modelling the wave-structure-seabed interaction. The numerical model selected and the resolution method depend mainly on the coastal study area, the importance and dependence of the processes involved, the temporal-spatial scale of the problem and the computational time.
  • 1.3K
  • 16 Jun 2021
Topic Review
Herring–Nabarro Creep
Nabarro–Herring creep is a mode of deformation of crystalline materials (and amorphous materials) that occurs at low stresses and held at elevated temperatures in fine-grained materials. In Nabarro–Herring creep (NH creep), atoms diffuse through the crystals, and the creep rate varies inversely with the square of the grain size so fine-grained materials creep faster than coarser-grained ones. NH creep is solely controlled by diffusional mass transport. This type of creep results from the diffusion of vacancies from regions of high chemical potential at grain boundaries subjected to normal tensile stresses to regions of lower chemical potential where the average tensile stresses across the grain boundaries are zero. Self-diffusion within the grains of a polycrystalline solid can cause the solid to yield to an applied shearing stress, the yielding being caused by a diffusional flow of matter within each crystal grain away from boundaries where there is a normal pressure and toward those where there is a normal tension. Atoms migrating in the opposite direction account for the creep strain ([math]\displaystyle{ \epsilon_{NH} }[/math]). The creep strain rate is derived in the next section. NH creep is more important in ceramics than metals as dislocation motion is more difficult to effect in ceramics.
  • 1.3K
  • 08 Nov 2022
Biography
Burt Rutan
Elbert Leander "Burt" Rutan (born June 17, 1943) is a retired American aerospace engineer and entrepreneur noted for his originality in designing light, strong, unusual-looking, energy-efficient aircraft. He designed the record-breaking Voyager, which in 1986 was the first plane to fly around the world without stopping or refueling, and the sub-orbital spaceplane SpaceShipOne, which won the Ansa
  • 1.3K
  • 22 Nov 2022
Topic Review
Additive Manufacturing Processes
Additive manufacturing (AM, 3D printing) is used in many fields and different industries. In the medical and dental field, every patient is unique and, therefore, AM has significant potential in personalized and customized solutions. This text explores what additive manufacturing processes and materials are utilized in medical and dental applications, especially focusing on processes that are less commonly used. The processes are categorized in ISO/ASTM process classes: powder bed fusion, material extrusion, VAT photopolymerization, material jetting, binder jetting, sheet lamination and directed energy deposition combined with classification of medical applications of AM. Based on the findings, it seems that directed energy deposition is utilized rarely only in implants and sheet lamination rarely for medical models or phantoms. Powder bed fusion, material extrusion and VAT photopolymerization are utilized in all categories. Material jetting is not used for implants and biomanufacturing, and binder jetting is not utilized for tools, instruments and parts for medical devices. The most common materials are thermoplastics, photopolymers and metals such as titanium alloys. If standard terminology of AM would be followed, this would allow a more systematic review of the utilization of different AM processes.
  • 1.3K
  • 09 Apr 2021
Topic Review
Slope Stability
The issue of slope stability is one of the most important and yet most difficult geotechnical problems. Assessing slope stability is particularly difficult because of the many uncertainties involved in the process. To take these uncertainties into account, probabilistic methods are used, and the reliability approach is adopted. There are many methods for reliability assessment of earth slope stability. However, there is no system that would organize all of these methods in an unambiguous way. In fact, these methods can be classified in different ways: by assignment to a deterministic classification of methods, by description of uncertainties of soil parameters, by level of reliability according to the theory of reliability, etc. The huge number of articles summarizing the research in this field, but in various “disordered” directions, certainly do not facilitate the understanding or ultimately the practical application of the reliability approach by the engineer. We propose a universal classification system of reliability methods for evaluating the stability of earth slopes. This proposal is preceded by a brief literature review of both historical background and contemporary study on reliability analysis of earth slope stability.
  • 1.3K
  • 17 Aug 2021
Topic Review
Best Estimate Plus Uncertainty Analysis in LBLOCA
As one of the Deterministic safety analysis (DSA) methodologies, best estimate plus uncertainty (BEPU) generates more realistic results that can be used in the license application of nuclear power plants (NPPs). However, uncertainty evaluation of parameters is needed in BEPU. The safety regulatory focuses on the large break loss of coolant accident (LBLOCA) of an advanced PWR. The BEPU analysis is mainly performed by TRACE V5.0 patch 4 code, and the uncertainty analysis is conducted based on DAKOTA code. 
  • 1.3K
  • 18 Feb 2022
Topic Review
Sakia
A saqia, alternative spelling sakieh, saqia or saqiya (from Arabic: ساقية, sāqiyah), also called Persian wheel, tablia, rehat, and in Latin tympanum is a mechanical water lifting device, similar in function to a scoop wheel, which uses buckets, jars, or scoops fastened either directly to a vertical wheel, or to an endless belt activated by such a wheel. The vertical wheel is itself attached by a drive shaft to a horizontal wheel, which is traditionally set in motion by animal power (oxen, donkeys, etc.) Because it is not using the power of flowing water, the sakia is different from a noria and any other type of water-wheel. It is still used in India , Egypt and other parts of the Middle East, and in the Iberian Peninsula and the Balearic Islands. It may have been invented in Hellenistic Egypt, Persia or India . The sakia was mainly used for irrigation, but not exclusively, as the example of Qusayr Amra shows, where it was used at least in part to provide water for a royal bathhouse.
  • 1.3K
  • 23 Nov 2022
Topic Review
Earth Sheltering
Earth sheltering is the architectural practice of using earth against building walls for external thermal mass, to reduce heat loss, and to easily maintain a steady indoor air temperature. Earth sheltering has become relatively more popular in modern times, especially among environmentalists and advocates of passive solar and sustainable architecture. However, the practice has been around for nearly as long as humans have been constructing their own shelters.
  • 1.3K
  • 27 Oct 2022
Topic Review
Avocado Peel Extracts in Topical Formulations
The avocado fruit, a derivative of the avocado tree of botanical name Persea americana Mill.. Avocado peel is a cheap and promising option for the retrieval of phenolic compounds, and it was reported that this by-product possesses higher total phenolic content, radical scavenging capacity, and antioxidant activity compared to the pulp. These results highlight the possibility of obtaining sustainable cosmetics, reducing significantly the negative impacts on the environment by the incorporation of extracts sourced from the avocado peel, an  interesting source of phenolic compounds, abundant and low-cost by-product.
  • 1.3K
  • 18 Mar 2022
Topic Review
Flexible Electronics
Flexible electronics is a rapidly growing technology for a multitude of applications. Wearables and flexible displays are some application examples.
  • 1.3K
  • 28 Jan 2021
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