Calibration and wide field imaging with PAPER: a catalogue of compact sources

Observations of the redshifted 21 cm HI line promise to be a formidable tool for cosmology, allowing the investigation of the end of the so-called dark ages, when the first galaxies formed, and the subsequent Epoch of Reionization when the intergalactic medium transitioned from neutral to ionized. Such observations are plagued by foreground emission which is a few orders of magnitude brighter than the 21 cm line. In this thesis I analyzed data from the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) in order to improve the characterization of the extragalactic foreground component. I derived a catalogue of unresolved radio sources down to a 5 Jy flux density limit at 150 MHz and derived their spectral index distribution using literature data at 408 MHz. I implemented advanced techniques to calibrate radio interferometric data that led to a few percent accuracy on the flux density scale of the derived catalogue. This work, therefore, represents a further step towards creating an accurate, global sky model that is crucial to improve calibration of Epoch of Reionization observations

CFD SIMULATION AND SHAPE OPTIMIZATION OF SUPERSONIC EJECTORS FOR REFRIGERATION AND DESALINATION APPLICATIONS

The aim of this thesis is to investigate the detailed flow field inside the supersonic ejector using numerical methods and to optimize the ejector’s mixing chamber wall shape to obtain a maximum entrainment ratio (ER) in order to obtain the highest possible efficiency that can be attained by the ejector. A steam ejector applied in the cooling industry is first studied to determine the most accurate turbulence model for its supersonic jet flow field simulation with mixing with the entrained steam in the mixing chamber. A commercial Computational Fluid Dynamics (CFD) package FLUENT 14.5 along with the meshing tool ICEM 14.5 is utilized to conduct the modeling and simulation to examine the ejector performance using two different turbulence models: k-ε realizable and k-ω SST. Velocity contours, pressure plots and entrainment ratio plots obtained from FLUENT are studied to investigate the effects of several ejector operating conditions as well as to verify the turbulence model accuracy by comparing the numerical results with experimental data. Simulations for three different supersonic ejectors (ejectors for refrigeration and desalination application with different working fluids namely the steam or compressed air) are conducted to further validate the numerical solution accuracy. The turbulence model producing more accurate results is applied to all three cases. In second part of the thesis, a single objective genetic algorithm (SOGA) is employed to optimize the mixing chamber wall shape for steam ejector for refrigeration to achieve the maximum entrainment ratio. Bezier Curves are used to generate the new wall shapes. The whole shape generation-meshing-simulation-SOGA process is repeated until the ER converges to a maximum value based on the specified convergence criteria for SOGA

ZAGREB INDICES OF A NEW SUM OF GRAPHS

The first and second Zagreb indices, since its inception have been subjected to an extensive research in the physio- chemical analysis of compounds. In [6] Hanyuan Deng et.al computed the first and second Zagreb indices of four new operations on a graph defined by M. Eliasi, B. Taeri in [4]. Motivated from this we define a new operation on graphs and compute the first and second Zagreb indices of the resultant graph. We illustrate the results with some examples

Structural model updating based on metamodel using modal frequencies

Modal frequencies are often used in structural model updating based on the finite element model, and metamodel technique is often applied to the corresponding optimization process. In this work, the Kriging model is used as the metamodel. Firstly, the influence of different correlation functions of Kriging model is inspected, and then the approximate capability of Kriging model is investigated via inspecting the approximate accuracy of nonlinear functions. Secondly, a model updating procedure is proposed based on the Kriging model, and the samples for constructing Kriging model are generated via the method of Optimal Latin Hypercube. Finally, a typical frame structure is taken as a case study and demonstrates the feasibility and efficiency of the proposed approach. The results show the Kriging model can match the target functions very well, and the finite element model can achieve accurate frequencies and can reliably predict the frequencies after model updating

Mirchi Data Management

IT outsourcing is becoming a very attractive option as a method to reduce overall cost especially in healthcare industry. When it comes to outsourcing, companies send their production, development, maintenance and support operations to another company that they contract with either locally or globally. Due to tremendous pace of outsourcing, increasingly there is concern growing that the data or the information used is vulnerable to confidentiality compromises. It means more and more IT operations are outsourced outside of the parent organization, more and more data and/or information need be accessed by external source. As per HIPAA (Health Insurance Portability and Accountability Act of 1996, Refer Appendix A – Government Acts and Regulations) regulation, all the Healthcare companies must protect patient health information from unnecessary access. However, there are situations where the outside contractors or a call center have to handle or work with sensitive data. How can a company protect patient privacy and still realize the cost savings from outsourcing? The answer is MIRCHI, the data management experts. MIRCHI’s innovative data encrypting solution offers companies a robust and seamless approach, which can be integrated to any environment and, encrypt and decrypt the incoming and outgoing data. MIRCHI expects to generate over 50 million in sales within the first 5 years of business by providing a data management solution. Note: The presentation associated with this report is included here as a supplemental file

ANTITUMOR AND CYTOTOXIC ACTIVITY OF GINGER ESSENTIAL OIL (ZINGIBER OFFICINALE ROSCOE)

Objective: To evaluate the cytotoxicty and antitumor activity of ginger essential oil (GEO).Methods: Cytotoxicity towards Dalton's Lymphoma Ascites (DLA) and Ehrlich Ascites Carcinoma (EAC) cell lines were evaluated by trypan blue exclusion method. In vitro cytotoxicity of GEO to L929 cells in culture were checked by MTT assay. The antitumor activity of GEO was determined by using DLA cell line induced solid tumor and EAC cell line induced ascites tumor model in mice and its comparison with standard anticancer drug cyclophosphamide.Results: GEO showed potent in vitro cytotoxic activity against DLA and EAC cell lines. IC50 value for DLA cell line was 11 μg/ml and for EAC cell lines 18 μg/ml. The IC50 of GEO was found to be 41 μg/ml against the L929 cell lines and to Vero cells was found to be ˃100 ug/ml. The treatment with GEO (500 mg/kg and 1000 mg/kg body weight) significantly reduced the volume of solid tumor development by 54.4% and 62.4% respectively. The life span was increased up to 50% in 1000 mg/kg b. wt GEO treated ascites tumor induced animals.Conclusion: This indicates the significant in vitro cytotoxic and antitumor properties of GEO suggesting its potential use as an anticancer agent.Â

The design, construction and deployment of PRIᶻM.

Doctoral Degree. University of KwaZulu-Natal, Durban.Abstract available in PDF.Author's publication list can be found on page ii of the thesis. Publications that form part and/or include research presented in this thesis: Probing Radio Intensity at high-Z from Marion: 2017 Instrument (Philip et al., 2018

Effects of Dielectrophoresis on Growth, Viability and Immuno-reactivity of Listeria monocytogenes

Dielectrophoresis (DEP) has been regarded as a useful tool for manipulating biological cells prior to the detection of cells. Since DEP uses high AC electrical fields, it is important to examine whether these electrical fields in any way damage cells or affect their characteristics in subsequent analytical procedures. In this study, we investigated the effects of DEP manipulation on the characteristics of Listeria monocytogenes cells, including the immuno-reactivity to several Listeria-specific antibodies, the cell growth profile in liquid medium, and the cell viability on selective agar plates. It was found that a 1-h DEP treatment increased the cell immuno-reactivity to the commercial Listeria species-specific polyclonal antibodies (from KPL) by ~31.8% and to the C11E9 monoclonal antibodies by ~82.9%, whereas no significant changes were observed with either anti-InlB or anti-ActA antibodies. A 1-h DEP treatment did not cause any change in the growth profile of Listeria in the low conductive growth medium (LCGM); however, prolonged treatments (4 h or greater) caused significant delays in cell growth. The results of plating methods showed that a 4-h DEP treatment (5 MHz, 20 Vpp) reduced the viable cell numbers by 56.8–89.7 %. These results indicated that DEP manipulation may or may not affect the final detection signal in immuno-based detection depending on the type of antigen-antibody reaction involved. However, prolonged DEP treatment for manipulating bacterial cells could produce negative effects on the cell detection by growth-based methods. Careful selection of DEP operation conditions could avoid or minimize negative effects on subsequent cell detection performance

Combination model of heterogeneous data for security measurement

Measuring security is a core step for guaranteeing security of network and information systems. Due to massiveness and heterogeneity of measurement data, it is difficult toclassify and combinethem on demand. In thispaper, consideringimplication relationship of metrics, we propose a combination model and combination policy for security measurement. Several examples demonstrate the effectiveness of our model

Effect of bis([beta]-chloroethyl)sulfide (BCES) on base mismatch repair of DNA in monkey kidney cells

Sulfur mustard, bis([beta]-chloroethyl)sulfide (BCES), a bifunctional alkylating agent, is a vesicant whose mode of action involves interference with the integrity of cellular DNA. Alkylation of DNA is responsible for some of the biological effects of BCES in tissue. Another possible mechanism by which BCES could exert its toxic effect is interference with high fidelity repair of damaged DNA. This study evaluated the possible effects of BCES on the repair of specific errors, i.e., mismatched bases, in the DNA. Heteroduplex (ht) DNA, formed between two temperature-sensitive mutants of SV40 virus, tsA239 and tsA255, each having a different point mutation in the gene for large T antigen, was used to study the effect of BCES on mismatched base repair in African green monkey kidney (AGMK) cells. AGMK cells were exposed to dilute solutions of BCES in methylene chloride (MC) prior to cationic lipofection with ht DNA. In order for the cells to produce wild type (wt) SV40 DNA at a nonpermissive temperature (41[deg]C), repair of at least one of the two mismatches in the DNA had to occur. It was observed that (a) as the concentration of BCES was increased, a proportionally longer delay in the appearance of wt DNA at 41[deg]C was observed in treated cells transfected with ht DNA as compared with cultures exposed to MC alone and then transfected with ht DNA, (b) there was no such effect in exposed AGMK cells transfected with wt DNA, (c) wt and ht DNA were transfected at similar rates in unexposed cells, and (d) BCES did not affect the rate of transfection of wt cells. These observations are consistent with the hypothesis that BCES affects mismatched base repair.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29053/1/0000086.pd