Modelling of a reverse flow catalytic membrane reactor for the partial oxidation of methane

Gas-To-Liquid (GTL) processes have great potential as alternative to conventional oil and coal processing for the production of liquid fuels. In GTL-processes the partial oxidation of methane (POM) is combined with the Fischer-Tropsch reaction. An important part of the investment costs of a conventional GTL-plant is related to cryogenic air separation. These costs could be substantially reduced by separating air with recently developed oxygen perm-selective perovskite membranes, which operate at similar temperatures as a POM reactor. Integration of these membranes in the POM reactor seems very attractive because oxygen reacts at the membrane surface resulting in a high driving force over the membrane increasing the oxygen permeation

Model of ionic currents through microtubule nanopores and the lumen

It has been suggested that microtubules and other cytoskeletal filaments may act as electrical transmission lines. An electrical circuit model of the microtubule is constructed incorporating features of its cylindrical structure with nanopores in its walls. This model is used to study how ionic conductance along the lumen is affected by flux through the nanopores when an external potential is applied across its two ends. Based on the results of Brownian dynamics simulations, the nanopores were found to have asymmetric inner and outer conductances, manifested as nonlinear IV curves. Our simulations indicate that a combination of this asymmetry and an internal voltage source arising from the motion of the C-terminal tails causes a net current to be pumped across the microtubule wall and propagate down the microtubule through the lumen. This effect is demonstrated to enhance and add directly to the longitudinal current through the lumen resulting from an external voltage source, and could be significant in amplifying low-intensity endogenous currents within the cellular environment or as a nano-bioelectronic device.Comment: 43 pages, 6 figures, revised versio

At the Gates: Analysis of Malicious Activity Facing Residential IP Addresses

The prevalence and permeation of technology in business has allowed for new and very creative ways to steal. With data breaches becoming more common (and more publicized), many people are aware of the threats that large companies face. However, the digital threats that a normal person faces are not as apparent. While many stories exist of people using technology to threaten or harass others, many are not necessarily aware of the threats these large scale data thieves pose to those who just simply own an always-on internet connection. This project was conceived as a way to see what threatens the common user. Using SecurityOnion, ESXI, and an unpatched operating system a simple network intrusion detection system was created to capture the reconnaissance traffic being sent to a residential IP address. The usage of ESXI allows for fast deployment of new exploitable systems as well as easy packet capture with virtual switches. SecurityOnion was used due to its’ ease of use and detailed tutorials. An unpatched, unregistered, and unprotected (no firewall or antivirus) copy of Windows XP was used as the honeypot. All unsolicited packets from unknown IP addresses were then analyzed for country of origin to gain statistics on where attackers are coming from (or rather where they wish to be seen coming from), as well as to see the most common ports that were being scanned for

Feasibility of Thermoplastic Extrusion Welding as a Joining Method For Vacuum-Assisted Additively Manufactured Tooling

In recent years, additive manufacturing (AM) has been successfully utilized for the production of large-scale composite tooling. Within these endeavors, however, limited research has focused on joining methods between printed sections. This work evaluates the feasibility of thermoplastic extrusion welding as a joining method for additively manufactured tooling structures. This joining method was assessed based on industry specifications of conventional thermoset tooling for wind blade manufacturing utilizing the vacuum-assisted resin transfer molding (VARTM) process. The specifications include requirements for the mechanical strength, vacuum integrity, roughness, and hardness of the tool surface. The feasibility of this welded polymer joint was demonstrated through subscale testing of 1” thick, welded, AM high-impact polystyrene (HIPS) plates. It was found that thermoplastic extrusion welds within AM components can maintain vacuum integrity at 20℃ with proper surface preparation and without a surface coating. This met the industry vacuum leakage specification of 10 millibar over 30 minutes with an average loss of 6.61 mbar over 30 minutes through the welded AM plate and bag system. Although beyond the industry specification, the vacuum leakage was further tested to evaluate performance at an infusion temperature of 80℃. At elevated temperature, the joint and plate lost approximately 26 mbar over 30 minutes. The surface finish was compared with hardness and roughness testing of the welded and machined AM surfaces, showing a decrease in hardness and roughness in the surface of the weld at both temperatures. Standardized ASTM mechanical testing of welded specimens showed an average comparative tensile strength of 80% of the base AM HIPS material. With the addition of undersurface reinforcement within the mold and a surface coating, extrusion welding shows promise for joining large-scale AM tool sections in a manufacturing environment

Development of vacuum insulation panel with low cost core material

This thesis was submitted for the degree of Doctor Philosophy and awarded by Brunel University LondonBrunel Universit

A Study of the effects of damage on 7781/E-795 E-glass/Eproxy laminates: Investigations of experimental techniques and development of a predictive model

Composite materials are used in a vast number of areas. Typical areas of use are in aircraft, space, and marine applications. Due to the nature of these applications, the materials may be exposed to various conditions which can inhibit their performance. Factors such as moisture and temperature are constantly changing, and measures must be taken to fully understand how environmental variations effect the performance of the components. Physical damage is also regularly encountered in these harsh environments as well as throughout the manufacturing and assembly of the products. The focus of this research is to explore and quantify the effects which these damage types have on the tensile strength of 7781/E-795 bi-directional E-glass/epoxy composite laminates after an environmental exposure. Orthogonal arrays and Taguchi Techniques were used to accomplish this task in an efficient, repeatable, and well structured manner. An exposure time/tensile strength predictive model is also developed which can be used to simulate and test material performance in an operational environment

Polymorphic computing abstraction for heterogeneous architectures

Integration of multiple computing paradigms onto system on chip (SoC) has pushed the boundaries of design space exploration for hardware architectures and computing system software stack. The heterogeneity of computing styles in SoC has created a new class of architectures referred to as Heterogeneous Architectures. Novel applications developed to exploit the different computing styles are user centric for embedded SoC. Software and hardware designers are faced with several challenges to harness the full potential of heterogeneous architectures. Applications have to execute on more than one compute style to increase overall SoC resource utilization. The implication of such an abstraction is that application threads need to be polymorphic. Operating system layer is thus faced with the problem of scheduling polymorphic threads. Resource allocation is also an important problem to be dealt by the OS. Morphism evolution of application threads is constrained by the availability of heterogeneous computing resources. Traditional design optimization goals such as computational power and lower energy per computation are inadequate to satisfy user centric application resource needs. Resource allocation decisions at application layer need to permeate to the architectural layer to avoid conflicting demands which may affect energy-delay characteristics of application threads. We propose Polymorphic computing abstraction as a unified computing model for heterogeneous architectures to address the above issues. Simulation environment for polymorphic applications is developed and evaluated under various scheduling strategies to determine the effectiveness of polymorphism abstraction on resource allocation. User satisfaction model is also developed to complement polymorphism and used for optimization of resource utilization at application and network layer of embedded systems

Development of CXCR4 Inhibitors for Topical Treatment of Psoriasis

Psoriasis is a chronic inflammatory skin disease that is often associated with systemic comorbidities and impaired skin barrier function. There are several treatment options including topical treatment with immunosuppressants, phototherapy, and systemic therapies using small molecules and biological agents. However, none of them can be regarded as a perfect solution due to their toxicity during chronic use. Recently, the CXCR4/SDF-1 axis was found to play an important role in the pathogenesis of psoriasis. AMD3100, a small molecule CXCR4 antagonist can selectively bind to CXCR4 and inhibit skin inflammation, reduce angiogenesis and infiltration of inflammatory cells. Unfortunately, AMD3100 can only be administered systemically. In this study, we aimed to develop CXCR4 inhibitor that can be applied topically in psoriasis as a way of reducing overall systemic toxicity of CXCR4 inhibition. We developed PAMD, a polycation based on AMD3100, as a topical drug to treat psoriasis. PAMD offers a great platform for chemical modification, drug combination, and the ability to form nanocarriers. Psoriasis is a skin disease therefore, it is desirable to deliver PAMD via a topical route to target the disease locally and improve safety and patient compliance. Stratum corneum (SC) is the foremost layer of skin, which acts as the main barrier to protect internal organs and limit the delivery of most drug molecules. Various attempts have been reported to increase skin penetration, including both passive and active iv methods. The mechanism of skin absorption is dependent on size, charge, and partition coefficients of the penetrant. Based on previous reports on the role of hydrophobicity and charge on skin penetration of polymers, our approach relied on modifying the PAMD with citraconic anhydride for a negative charge and oleic acid for lipophilicity. The best performing negatively charged PAMD demonstrated low toxicity in HaCaT cells in vitro, and high retention and deep penetration in both healthy and psoriatic skin models. The favorable level of penetration may be due to the acidic skin environment and the intercellular transportation within SC, facilitated by the attraction of the polymer and diffusion respectively. IMQ-induced psoriasis mouse model was attenuated by a topical application of PAMD, PAMD.COO-, and subcutaneous injection of AMD3100. This observation provided evidence supporting that blockade of CXCR4/SDF-1 cascade reduces skin inflammation related to the decreased mRNA levels of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. The topical application of CXCR4 antagonistic polymers exhibited comparable in vivo therapeutic effects as systemic administration of AMD3100. Moreover, the penetration of the polymer had no influence on anti-psoriatic activity in mice