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Topic Review
Oil Spill Modeling
Several oil spill simulation models exist in the literature, which are used worldwide to simulate the evolution of an oil slick created from marine traffic, petroleum production, or other sources. These models may range from simple parametric calculations to advanced, new-generation, operational, three-dimensional numerical models, coupled to meteorological, hydrodynamic, and wave models, forecasting in high-resolution and with high precision the transport and fate of oil. This study presents a review of the transport and oil weathering processes and their parameterization and critically examines eighteen state-of-the-art oil spill models in terms of their capacity (a) to simulate these processes, (b) to consider oil released from surface or submerged sources, (c) to assimilate real-time field data for model initiation and forcing, and (d) to assess uncertainty in the produced predictions. Based on our review, the most common oil weathering processes involved are spreading, advection, diffusion, evaporation, emulsification, and dispersion. The majority of existing oil spill models do not consider significant physical processes, such as oil dissolution, photo-oxidation, biodegradation, and vertical mixing. Moreover, timely response to oil spills is lacking in the new generation of oil spill models. Further improvements in oil spill modeling should emphasize more comprehensive parametrization of oil dissolution, biodegradation, entrainment, and prediction of oil particles size distribution following wave action and well blow outs.
  • 1.7K
  • 02 Mar 2021
Topic Review
GVL Production with Levulinic Acid
Levulinic acid (LA) is considered as one of the “Top 10” building blocks for future bio-refineries as proposed by the US Department of Energy. It is  one of the most important platform molecules for the production of fine chemicals and fuels based on its compatibility with existing processes, market economics, and industrial ability to serve as a platform for the synthesis of important derivatives. Hydrogenation of LA to produce γ-valerolactone (GVL) is an active area of research due to the potential of GVL to be used as a biofuel in its own right and for its subsequent transformation into hydrocarbon fuels. This paper contains a new design for a simple, cost effective, and safe hydrogenation reactor for the transformation of levulinic acid to γ-valerolactone (GVL) by utilizing high boiling point organic fluid. The hydrogenation reactor is composed of a heating source—organic fluid (called “DOWTHERM A” or “thermex”) and the catalytic reactor. The advantages of high boiling temperature fluids, along with advances in hydrocracking and reforming technologies driven by the oil and gas industries, make the organic concept more suitable and safer (water coming in contact with liquid metal is well understood in the metallurgical industry to be a steam explosion hazard) for heating the hydrogenation reactor. COMSOL multi-physics software version 4.3b was applied in this work and simultaneously solves the continuity, Navier-Stokes (fluid flow), energy (heat transfer), and diffusion with chemical reaction kinetics equations. It was shown that the heat flux supplied by the DOWTHERM A organic fluid could provide the necessary heat flux required for maintaining the hydrogenation process. It was found that the mass fractions of hydrogen and levulinic acid decreased along the reactor axis. The GVL mass fraction increased along the reactor axis.
  • 1.7K
  • 30 Oct 2020
Topic Review
Beam-Squinting Effect in Broadband Mobile Communication
Due to the fact that the quality of the received signal is adversely affected by the beam squint phenomenon, which is especially pertinent to the millimeter wave (mmwave) bands, many studies have been utilised by other researchers to provide light on some of the challenges that come with analysing this type of occurrence. Squint causes several issues, the most important of which are its detrimental effects on gain, line of sight, angle of arrival, progressive phase, usable bandwidth, and fading effect. As a result of these obstacles, the advantages of adopting a high-frequency band such as mmwave in modern wireless communication systems are severely limited.
  • 1.7K
  • 06 Feb 2023
Topic Review
Unconventional Reservoirs
The world’s energy demand is steadily increasing where it has now become not easy for conventional hydrocarbon reservoirs to meet levels of demand. Therefore, oil and gas companies are seeking novel ways to exploit and unlock the potential of unconventional resources. Drilling of high-pressure high-temperature (HPHT) wells and shale reservoirs has become more widespread in the global petroleum and natural gas industry. There is a current need to extend robust techniques beyond costly drilling and completion jobs, with the potential for exponential expansion. This paper explains a better understanding of the selection of drilling fluids and additives for unconventional hydrocarbon reservoirs. 
  • 1.7K
  • 13 Jul 2020
Topic Review
Pavement Surface Types and Distress Assessment Indicators
Pavement or road surfaces can be categorized into four general classes, i.e., asphalt, concrete, gravel, and brick and block. Pavement condition is assessed by measuring several pavement characteristics such as roughness, surface skid resistance, pavement strength, deflection, and visual surface distresses.
  • 1.7K
  • 29 Nov 2022
Topic Review
Impact of Strategy Change on Business Process Management
In the pursuit of economic survival in the current competitive conditions with the aim of long-term prosperity and sustainability in the market, many companies today approach significant strategic changes in the management of their business. The design of a systematic procedure for implementing strategy changes into internal business processes for a project-oriented production type of organization is of importance. 
  • 1.7K
  • 14 Sep 2022
Topic Review
Properties and Characteristics of C6F12O
In order to cope with the problem that no gas fire suppressant can be used in the future, perfluoro-2-methyl-3-pentanone (C6F12O), also known as FK-5112, Novec 1230 or Novec 649, with its environmentally friendly performance, zero ODP, GWP of approximately one and atmospheric lifetime of up to two weeks (as shown in Table 1), has been considered as the next generation of halon alternatives. C6F12O belongs to fluorinated ketones which is different to HFCs. Its nontoxicity, noncombustibility, excellent insulation properties and fire suppression efficiency have attracted worldwide attention. The thermophysical parameters, safety and environmental issues and other properties such as the dispersion characteristics of C6F12O are important indexes to evaluate whether it is appropriate to replace the halon. Meanwhile, these properties and parameters are critical to determine the application scenes of fire suppressant, the selection of fire extinguishment facilities and the engineering calculation of the fire extinguishment system.
  • 1.7K
  • 18 Apr 2022
Topic Review
Springfield Armory XDM
The Springfield Armory XDM (X-Treme Duty, the M is for the match grade barrel and match grade trigger) are a series of semi-automatic pistols that are polymer-framed and striker-fired. They closely resemble their predecessor, the HS2000 pistol (most widely known in the United States as Springfield Armory XD). Manufactured in the city of Karlovac, Croatia by HS Produkt (formerly I.M. Metal), the Springfield Armory XDM is the marketing name for the firearm, which is licensed and sold in the United States by Springfield Armory, Inc..
  • 1.7K
  • 25 Oct 2022
Topic Review
Distributed Element Circuit
Distributed element circuits are electrical circuits composed of lengths of transmission lines or other distributed components. These circuits perform the same functions as conventional circuits composed of passive components such as capacitors, inductors, and transformers. They are used mostly at microwave frequencies where conventional components are difficult or impossible to implement. A major advantage of distributed element circuits is that they can be produced cheaply as a printed circuit board for consumer products such as satellite television. They are also made in coaxial and waveguide formats for applications such as radar, satellite communication, and microwave links. A phenomenon that is much used in distributed element circuits is that a length of transmission line can be made to behave as a resonator. Distributed element components that do this include stubs, coupled lines, and cascaded lines. Circuits built from these components include filters, power dividers, directional couplers, and circulators. Distributed element circuits were investigated in the 1920s and 1930s but did not become important until World War II when they were used in radar. After the war their use was at first limited to military, space, and broadcasting infrastructure use but improvements in materials science in the field soon led to wider applications.
  • 1.7K
  • 17 Oct 2022
Topic Review
Liquid-Organic Hydrogen Carrier
Molecular liquid that can accommodate and release hydrogen molecules via chemical hydrogenation and dehydrogenation.
  • 1.7K
  • 04 Dec 2020
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