Functionalization Of 2d-Zno for Selective Gas Sensing: First-Principles Analysis

The scope of this MSc thesis is to theoretically search for suitable materials and relevant factors (e.g., dopants and catalysts) to induce gas sensing (GS) selectivity towards harmful gases such as H2, H2S, and CO2, under ambient conditions. We chose as material 2D-ZnO Honeycomb in the form of nanoribbon (ZnO-NR), which is very promising in the gas sensing applications. We employed a state-of-the-art computational method, based on a combination of the density-functional theory (DFT) and the Non-Equilibrium Green’s Functions (NEGF) formalism, which both are incorporated in Atomistic Toolkit (ATK) package. This package is famous for its reliability in estimating the IV characteristics. The thesis consists of three phases: (1) Effect of dopants on gas sensing: Three organic-atoms (e.g., N, C, F) were initially attempted. But selectivity towards the detection of H2 was achieved only in N-doped ZnO-NR. Special trend, discovered about the secrete of such selectivity, was the existence of negative differential resistance (NDR) in the IV characteristics of ZnONR: N. (2) Origins of NDR: the previous results led us to search for the origins of NDR in N-doped ZnO-NRs. We have investigated the effect of placing the doping atom N in three different positions across ZnO-NR, with respect to the edges (i.e.(i) at the Oric hedge, (ii) at the center, and (iii) at the Zn-rich edge.) Results show a clear trend that NDR shifts to higher energies than Fermi level, as well as both NDR and the Topto-Valley-Current Ratio (TVCR), get reduced, when N-atom is moved from O-rich to Zn-rich edges. We concluded that the unpaired electron on N-atom when it gets charged, causes the localization/curdling of the wave function at Fermi-level and consequently causes backscattering and drawback of current (so named NDR). (3) Effect of catalysts on gas sensing: Five transition-metal atoms (Pt, Pd, Au, Ag, and Fe) were used as ad-atom decorating ZnO-NR aiming to induce selectivity towards gases of interest (H2, H2S, and CO2) in existence of other gases (e.g., O2, N2, and H2O) at room temperature (RT). Results show that both Pt and Pd have poor selectivity at RT. Whereas, Fe is found to yield high selectivity toward detecting CO2, while both Au and Ag have selectivity towards H2S, at RT. All our findings are in excellent agreement with experimental data

LEVERAGING SOA IN BANKING SYSTEMS INTEGRATION

There is no doubt that the systems integration is one of the most important and complicated tasks in software filed especially for complex applications like banking systems. Complexity in integrating banking systems often comes from continues changes in both technical and business features provided by them to meet customer needs. Banking systems always come from different software vendors which mean using platforms and different design and architecture patterns, and this for sure adds extra complexity for integrating them. Serviceoriented architecture (SOA) is a promising method in software filed that aims to build or restructure software systems in a manner that makes their maintenance and integration easier. Agility is the most important goal that should be achieved when building and integrating banking systems. Simply, agility is needed to meet market needs quickly and efficiently and SOA is the way that could provide itSOA, SOI, P2P Integration, Web Services, and Legacy Code

The physics and kinematics of the evolved, interacting planetary nebula PN G342.0-01.7

Here we aim to study the physical and kinematical characteristics of the unstudied old planetary nebula (PN) PN G342.0-01.7, which shows evidence of interaction with its surrounding interstellar medium. We used Integral Field Spectra from the Wide Field Spectrograph on the ANU 2.3 m telescope to provide spectroscopy across the whole object covering the spectral range 3400-7000 {\AA}. We formed narrow-band images to investigate the excitation structure. The spectral analysis shows that the object is a distant Peimbert Type I PN of low excitation, formally of excitation class of 0.5. The low electron density, high dynamical age, and low surface brightness of the object confirm that it is observed fairly late in its evolution. It shows clear evidence for dredge-up of CN-processed material characteristic of its class. In addition, the low peculiar velocity of 7 km s$^{-1}$ shows it to be a member of the young disk component of our Galaxy. We built a self-consistent photoionisation model for the PNe matching the observed spectrum, the H$\beta$ luminosity, and the diameter. On the basis of this we derive an effective temperature $\log T_{\rm eff} \sim 5.05$ and luminosity $1.85 < \log L < 2.25$. The temperature is much higher than might have been expected using the excitation class, proving that this can be misleading in classifying evolved PNe. PN G342.0-01.7 is in interaction with its surrounding interstellar medium through which the object is moving in the south-west direction. This interaction drives a slow shock into the outer PN ejecta. A shock model suggests that it only accounts for about 10\% of the total luminosity, but has an important effect on the global spectrum of the PN.Comment: 15 pages, 6 figures, A&A accepted 201

Data Mining Techniques for Wind Speed Analysis

Weather Data Mining is a form of Data mining concerned with finding hidden patterns inside largely available meteorological data, so that the information retrieved can be transformed into usable knowledge. In this paper we used meteorological data mining to analyze wind speed behavior. The data was recorded between 2004 to November 2006 daily historical data by meteorological station of Gaza. After preprocessing the data, we applied data mining techniques: association rules, classification, cluster and outlier analysis. From these four tasks, we found the most appropriate of these techniques to be applied on weather data is classification task, especially the neural networks method because the nature of the data is time series

Discovery of a 6.4 keV Emission Line in a Burst from SGR 1900+14

We present evidence of a 6.4 keV emission line during a burst from the soft gamma-ray repeater SGR 1900+14. The Rossi X-ray Timing Explorer (RXTE) monitored this source extensively during its outburst in the summer of 1998. A strong burst observed on August 29, 1998 revealed a number of unique properties. The burst exhibits a precursor and is followed by a long (~ 1000 s) tail modulated at the 5.16 s stellar rotation period. The precursor has a duration of 0.85 s and shows both significant spectral evolution as well as an emission feature centered near 6.4 keV during the first 0.3 s of the event, when the X-ray spectrum was hardest. The continuum during the burst is well fit with an optically thin thermal bremsstrahlung (OTTB) spectrum with the temperature ranging from about 40 to 10 keV. The line is strong, with an equivalent width of 400 eV, and is consistent with Fe K-alpha fluorescence from relatively cool material. If the rest-frame energy is indeed 6.4 keV, then the lack of an observed redshift indicates that the source is at least 80 km above the neutron star surface. We discuss the implications of the line detection in the context of models for SGRs.Comment: AASTex preprint, 14 pages, 3 embedded figures. Accepted for Publication in Astrophysical Journal Letter

Utility of Certain Nucleophilic Aromatic Substitution Reactions for the Assay of Ethamsylate in its Dosage forms and in Presence of its Degradation Product

The study represents the first report on the development of spectrophotometric methods for determination of ethamsylate (EST) in the presence of hydroquinone as an impurity and/or acidic degradation product. The proposed methods are based on the reaction of EST through it,s secondary amino group either with 1,2-naphthoquinone-4-sulphonate sodium (NQS) at pH 10.7 or 2,4-dinitrofluorobenzene (DNFB) at pH 9.3 to form orange and yellow colored reaction products peaking at 478 and 387 nm for methods (I) and (II), respectively. The different experimental parameters affecting the development and stability of the reaction products in methods (I) and (II) were carefully studied and optimized. The absorbance-concentration plots were rectilinear over the concentration ranges of 2-30 and 2-14 µg mL−1 for methods (I) and (II), respectively. The lower detection limits were 0.13 and 0.19 µg mL−1 and the lower quantitation limits were 0.44 and 0.63 µg mL−1 for methods (I) and (II), respectively. Both methods were successfully applied to commercial ampoules and tablets

Seatbelts and road traffic collision injuries

Modification of seatbelts and their legislation played an important role in reducing morbidity and mortality of occupants in road traffic collisions. We aimed to review seatbelt development, its mechanism of action and its effects. Seatbelts reduce injury by preventing the occupant from hitting the interior parts of the vehicle or being ejected from the car. We have made a linear regression correlation between the overall seatbelt compliance and road traffic death rates in 46 high income countries to study the relationship between seatbelt use and mortality. There was a very highly significant negative correlation between the seatbelt compliance and road traffic death rates (R = - 0.77, F = 65.5, p < 0.00001). Seatbelt-related injuries include spinal, abdominal or pelvic injuries. The presence of a seatbelt sign must raise the suspicion of an intra-abdominal injury. These injuries can be reduced if seatbelts were applied correctly. Although seatbelts were recognized as an important safety measure, it still remains underused in many countries. Enforcement of seatbelt usage by law is mandatory so as to reduce the toll of death of road traffic collisions

NM-LEACH: A Novel Modified LEACH Protocol to Improve Performance in WSN

Saving energy and improving the lifetime of wireless sensor networks (WSNs) has remained as a key research challenge for some time. Low-energy adaptive clustering hierarchy (LEACH), a classical protocol is designed originally for the purpose of reducing and balancing the network’s energy consumption. However, as the distances between the cluster head (CH) and the member nodes are not taken into consideration, it results in the uneven distribution of the clusters and uneven consumption of the energy in the network. Choosing the CHs with no distinction is an issue as well. Based on the original algorithm, a novel modified LEACH (NM-LEACH) has been proposed, considering critical problems that exist in the network. NM-LEACH protocol is capable of reasonably solving the number of the CHs in each round and takes the energy as a factor of weight under consideration in selecting the CH. The proposed protocol enhances performance by extending the WSN lifecycle, which results in increasing the balance of the energy consumption in the network, and improving the efficiency of the network

Temperature dependence of J–V and C–V characteristics of n-InAs/p-GaAs heterojunctions prepared by flash evaporation technique and liquid phase epitaxy

In this work, n-type of InAs films have been successfully fabricated on p-GaAs monocrystalline substrates by both flash evaporation technique and liquid phase epitaxy. The elemental composition of the prepared films has been confirmed by energy dispersive X-ray (EDX) spectroscopy. The morphology of the films has been characterized by scanning electron microscopy (SEM). The current transport mechanisms of n-InAs/p-GaAs heterojunctions in the temperature range 300-400 K have been investigated. Temperature-dependent dark current density-voltage (J–V) studies under forward and reverse bias have been carried out for this purpose. In the temperature range studied, the dark current contribution in the low bias range is believed to be due to the generation-recombination of minority carriers in the space-charge region. A change in the preparation technique does not seem to have altered the dark current conduction mechanism. Capacitance-voltage (C–V) at various temperatures has been measured to identify the junction type as well as determination of the important junction parameters

Effect of nitric oxide donors on uterine and sub-endometrial blood flow in patients with unexplained infertility: a randomized controlled trial

Background: Impaired sub-endometrial perfusion might reduce endometrial receptivity and possibly contribute to unexplained infertility. A favorable effect on sub-endometrial blood flow has been demonstrated with nitric oxide.Methods: This randomized controlled trial evaluated the effect of nitroglycerine on uterine and sub-endometrial blood flow in women with unexplained infertility. Sixty women were randomized into 2 equal groups. The study group received 5mg nitroglycerine patch daily from day 2 of the cycle till the evaluation day and the control group received no treatment. Independent of the study arms, 30 parous women were included as the fertile group. Six to eight days after detecting luteinizing hormone surge, women were assessed for endometrial thickness, uterine artery blood flow with color Doppler and sub-endometrial blood flow with three-dimensional power Doppler.Results: Compared to fertile women, cases with unexplained infertility (control group) had a significantly thinner endometrium, higher uterine artery Doppler indices and lower sub-endometrial blood flow. Women who received nitroglycerin showed a significant improvement in sub-endometrial blood flow while uterine artery blood flow did not show a significant difference; however, the values were also comparable to fertile women. In addition, no effect on endometrial thickness was found with nitroglycerin treatment. Nitroglycerin treatment side effects were headache, blurring of vision and hypotension. These adverse effects were not significant compared to controls.Conclusions: In women with unexplained infertility, nitroglycerin significantly improved the sub-endometrial blood flow but did not affect the endometrial thickness