ANALYSIS OF PRESSURE DROP AND HEAT TRANSFER OF ANNULAR DEPOSITION TEST UNIT

Deposition of wax on the internal wall of pipelines is often regarded as a problem since the tube diameter is reduced. Consequently, more power is needed to force the same amount of oil through the system. In order to design efficient sub-sea petroleum production facilities to achieve optimum production returns, it is necessary to understand the phenomena of the wax deposition and provide prediction for the nature of deposits. PETRONAS High Temperature/High Pressure Model Pipeline and Wax Deposition Facility, HT/HPMPWDF, is designed and installed, to investigate and model the process of the wax deposition. In this system, pressure drop and heat transfer are proposed as the key parameters to model the process of the wax deposition. Experiments were carried out to investigate and characterize the hydrothermal performance of the test section of the system. Pressure drop and temperature variation data throughout the test section of the deposition apparatus with varying flow condition were measured and processed analytically. Also, pressure drop and heat transfer data were predicted based on the available correlations. Comparison was made between the two models. For each parameter involved in the pressure drop calculations, a parametric analysis was performed to study its effect on the pressure drop estimation. The discrepancies between the measured and calculated pressure drop results were justified and a realistic pressure drop correlation was developed based on the equivalent length technique. The heat transfer was investigated in terms of the steady state energy balance. Also, several heat transfer correlations were used to predict the heat transfer. Comparison between the theoretical and experimental results reveals that Sandal et. a!. correlation for the convective heat transfer is produced the best agreement with the experimental results. The system is proved to provide an experimental data within an accuracy of 7 % AAPE for the pressure drop and 5% AAPE for the turbulent convective heat transfer. A steady state thermal energy balance of 6 % AAPE is achieved. It could be concluded that the proposed correlations have brought the system to the capability of modeling and predicting the wax deposition formation

CorrFL: Correlation-Based Neural Network Architecture for Unavailability Concerns in a Heterogeneous IoT Environment

The Federated Learning (FL) paradigm faces several challenges that limit its application in real-world environments. These challenges include the local models' architecture heterogeneity and the unavailability of distributed Internet of Things (IoT) nodes due to connectivity problems. These factors posit the question of "how can the available models fill the training gap of the unavailable models?". This question is referred to as the "Oblique Federated Learning" problem. This problem is encountered in the studied environment that includes distributed IoT nodes responsible for predicting CO2 concentrations. This paper proposes the Correlation-based FL (CorrFL) approach influenced by the representational learning field to address this problem. CorrFL projects the various model weights to a common latent space to address the model heterogeneity. Its loss function minimizes the reconstruction loss when models are absent and maximizes the correlation between the generated models. The latter factor is critical because of the intersection of the feature spaces of the IoT devices. CorrFL is evaluated on a realistic use case, involving the unavailability of one IoT device and heightened activity levels that reflect occupancy. The generated CorrFL models for the unavailable IoT device from the available ones trained on the new environment are compared against models trained on different use cases, referred to as the benchmark model. The evaluation criteria combine the mean absolute error (MAE) of predictions and the impact of the amount of exchanged data on the prediction performance improvement. Through a comprehensive experimental procedure, the CorrFL model outperformed the benchmark model in every criterion.Comment: 17 pages, 12 figures, IEEE Transactions on Network and Service Managemen

Experimental study of natural convection heat transfer and gaseous dynamics from dual-channel circulation loop

This research focuses on establishing a range of scaled separate and integral effects experiments for studying thermal-hydraulic behavior occurring within a component or region of the prismatic very high-temperature reactor (VHTR) such as plenum-to-plenum heat transfer and gaseous dynamics during natural circulation. Natural circulation of the coolant is the leading capability for VHTR to transport the decay heat from the core to the reactor vessel during accident scenarios. To address this need, a scaled-down facility is designed and developed with only two channels with upper and lower plena. The emphasis is placed on high-resolution and high-fidelity experimental data for local heat transfer and gaseous dispersion measurements utilizing sophisticated techniques under different operating conditions. These techniques are 1) non-invasive flush wall mounted heat transfer coefficient probe to measure reliably the heat flux and surface temperature along the flow channels, and by measuring simultaneously these two variables and the flowing fluid, the heat transfer coefficient can be obtained, 2) radial temperature sensor adjuster to measure radial temperature variations of the coolant along the flow channels, and 3) advanced gaseous tracer technique to accurately measure the residence time distribution (RTD) in an of flow systems by injecting pulse change gas tracer and then monitoring its concentration at the exit. The measured RTD is utilized to quantify the gas dispersion and identify the degree of mixing in the system. The obtained local heat transfer and gaseous dispersion data in this study will provide high spatial and temporal resolutions benchmarking data for validating heat transfer and gaseous dispersion computations and correlations that are integrated with CFD simulations --Abstract, page iv

Optoacoustic frequency stabilization of a carbon dioxide laser

In this thesis a study has been made of the design, construction and, in particular, frequency stabilization of a d.c. excited carbon dioxide laser. The outline of the theory of the carbon dioxide laser is presented as a prelude to a detailed study of optogalvanic and optoacoustic effects. Experimental investigations have been made of both of these phenomena, and the results used for frequency stabilization of a conventional large tube diameter flowing gas type of carbon dioxide laser. A special feature of the work is intra-cavity optoacoustic detection of laser power by carbon dioxide gas absorption within the laser tube itself but outside the plasma region, for a new method of frequency stabilization. It is shown experimentally that this novel method is superior to the well established optogalvanic technique of frequency stabilization, in terms of signal to noise ratio and short response time. Extension of the intra-cavity optoacoustic method to both d.c. and r.f. excited waveguide lasers is discussed

Terpenoid cell factory

Terpenen vormen de grootste, meest gevarieerde groep van natuurproducten met talrijke toepassingen als voedingssupplement of geneesmiddel. In de natuur worden de meeste terpenen in lage concentraties aangemaakt, hetgeen betekent dat hun zuivering gepaard gaat met dure extracties en met de consumptie van grote hoeveelheden natuurlijke hulpbronnen. Het uitsterven van de natuurlijke bron is soms een reële bedreiging als de hoeveelheid te isoleren verbindingen de marktvraag kan niet dekken, zoals voor het antikankermiddel paclitaxel en het antimalariamiddel artemisinine. Chemische synthese van de meeste terpenen is problematisch en duur als gevolg van de complexiteit van hun structuren. Er is dus een dringende behoefte aan alternatieve methoden voor terpeen productie. Een van de veelbelovende nieuwe methoden is de engineering van micro-organismen ten behoeve van de productie van terpenen. De tweeledige doelstelling van het proefschrift van Ingy Abdallah is het onderzoeken van de grampositieve bacterie Bacillus subtilis als platform voor de productie van terpeen én de verbetering van de biosynthetische routes van terpenen inclusief kern enzymen zoals terpeen synthases. Als resultaat van dit onderzoek is nu een nieuwe B. subtilis stam beschikbaar gekomen, waarin de terpeen biosynthese route succesvol hoog tot expressie is gebracht. Deze “Cell Factory” is gebruikt voor de productie van C30 carotenoïden en de diterpeen voorloper van paclitaxel, taxadiene. Deze nieuwe gastheer kan dienen als een universele cel-fabriek voor de productie van waardevolle terpenen. Het onderzoek in dit proefschrift is verder verdiept met een analyse van de enzym-familie van terpeen synthases. Dit heeft geleid tot een veel beter begrip van de structuur-functie relaties van amorphadiene synthase, een sleutelenzym in de productie van artemisinine, en, niet onbelangrijk, tot de verbetering van de katalytische activiteit

Antibacterial activity of Moringa oleifera methanolic leaves extracts against some Gram-positive and Gram-negative bacterial isolates

Background: Moringa oleifera Lam. (Moringaceae) found to be very useful tree in tropical countries. In folklore and Ayurvedic all parts of the tree used in different healing procedures for different diseases. The plant leaves are very good nutrient supplement for malnutrition and also used as an antibiotic. Methods: Phytochemical analysis of the leaf in solvents of varying polarity; viz., Aqueous and Methanol were also carried out. The phytochemical screening indicated the presence of phenolics, flavonoids, tannins, glycosides etc. Results: The antibacterial activity of Moringa oleifera leaf extracts against four microorganisms, viz. Escherichia coli, Shigella Staphylococcus aureus and streptococcus, The Methanolic extract was active against E.coli, Shigella, Staphylococcus aureus whereas the aqueous extract exhibited an inhibitory effect on Pneumonia, E. coli and Shigella only at different zone of inhibition levels of extracts. Well diffusion method was used to assess the antibacterial effect of the extracts on both Gram positive and Gram negative micro-organisms. Moreover, the statistically, results were not significant at both 1% and 5% level of significances. Conclusion: It became obvious that, the higher reducing power of the aqueous extract could be due to the better solubility of the antioxidant components in water whereas the predominant antibacterial activity in organic solvent extracts as compared to aqueous extracts, indicated that the active components responsible for the bactericidal activity are more soluble in organic solvents. This study provided an evidence to support traditional medicinal uses of the plant

Solving Modal Equations of Motion with Initial Conditions Using MSC/NASTRAN DMAP

By utilizing MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) in an existing NASA Lewis Research Center coupled loads methodology, solving modal equations of motion with initial conditions is possible using either coupled (Newmark-Beta) or uncoupled (exact mode superposition) integration available within module TRD1. Both the coupled and newly developed exact mode superposition methods have been used to perform transient analyses of various space systems. However, experience has shown that in most cases, significant time savings are realized when the equations of motion are integrated using the uncoupled solver instead of the coupled solver. Through the results of a real-world engineering analysis, advantages of using the exact mode superposition methodology are illustrated

Solving modal equations of motion with initial conditions using MSC/NASTRAN DMAP. Part 1: Implementing exact mode superposition

Within the MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) module TRD1, solving physical (coupled) or modal (uncoupled) transient equations of motion is performed using the Newmark-Beta or mode superposition algorithms, respectively. For equations of motion with initial conditions, only the Newmark-Beta integration routine has been available in MSC/NASTRAN solution sequences for solving physical systems and in custom DMAP sequences or alters for solving modal systems. In some cases, one difficulty with using the Newmark-Beta method is that the process of selecting suitable integration time steps for obtaining acceptable results is lengthy. In addition, when very small step sizes are required, a large amount of time can be spent integrating the equations of motion. For certain aerospace applications, a significant time savings can be realized when the equations of motion are solved using an exact integration routine instead of the Newmark-Beta numerical algorithm. In order to solve modal equations of motion with initial conditions and take advantage of efficiencies gained when using uncoupled solution algorithms (like that within TRD1), an exact mode superposition method using MSC/NASTRAN DMAP has been developed and successfully implemented as an enhancement to an existing coupled loads methodology at the NASA Lewis Research Center

INTRANASAL MICROEMULGEL AS SURROGATE CARRIER TO ENHANCE LOW ORAL BIOAVAILABILITY OF SULPIRIDE

Objective: The purpose of this study is to evaluate microemulsion based gel (MBG) of sulpiride "a poorly water soluble antipsychotic with low oral bioavailability."Methods: Gelling polymers such as sodium carboxymethylcellulose (CMC-Na), hydroxyl propyl methyl cellulose (HPMC K4m), carbopol 940 and Na alginate were evaluated for their potential to gel sulpiride microemulsions (MEs) without affecting the MEs structure. Also, sulpiride solution (SS) and conventional gel (without ME) were prepared and compared with MBG. Gel formulations were checked for their viscosity, pH, spreadability (S), mucoadhesive force (MF), and nasal ciliotoxicity studies. The in vitro release of sulpiride across a cellophane membrane and its permeation through the nasal mucosa in phosphate buffered saline pH 6.8 (PBS) were also performed. In addition, a pharmacodynamic study of optimized formulae compared to SS and microemulsion (ME) was evaluated in rats.Results: CMC-Na and HPMC K4m were not able to gel sulpiride loaded MEs while Na alginate gave an unclear gel with a sticky texture. Results revealed that the viscosity, mucoadhesion force, and spreadability of the MBG increased with increasing carbopol 940 concentrations. The flux was arranged as the following, MBG>conventional gel>sulpiride solution (SS). According to histopathological study, safe and non-irritant MBGs suitable for nasal administration were successfully prepared. Finally, the pharmacodynamic study indicated that intranasal sulpiride MBG had a significant effect (*P<0.001) than SS and ME administered either intravenous or intranasal.Conclusion: MBG provides signiï¬cant enhancement in nasal bioavailability not only by absorption enhancing effect of ME but also, by increasing nasal residence tim

Impact of Fading Wireless Channel on The Performance of Game Theoretic Power Control Algorithms for CDMAWireless Data

Our goal in this paper is to study the performance of the game-theoretic power control algorithms for wireless data introduced by Saraydar et al [1] in two realistic channels: (a1) fast flat fading channel and (a2) Slow flat fading channel. The fading coefficients under both (a1) and (a2) are studied under an appropriate small scale channel model that is used in the CDMA cellular systems, namely Nakagami channel model. To do so, we derive a closed- form expression of the average utility function which represents the number of bits received correctly at the receiver per one Joule expended. Then, using this expression we study the existence, uniqueness of Nash equilibrium (NE), and the social desirability of NE in the Pareto sense