Lean premixed swirl stabilised combustion is regarded as one of the most successful technologies for flame control and NOx reduction. The important characteristics of these flows are the good mixing, flame stability through the formation of a Central Recirculation Zone, and the low emissions at lean conditions as a consequence of temperature drop. Now the potential wide range of available fuels presents a problem in terms of variation of heating values, flame speeds and chemical reactivity. Process, refinery gases and gasified coal or biomass are just a few examples. The biggest challenge to fuel-flexibility of most combustors is the large differences between natural gas and the proposed replacement fuels which causes variations in the stability profiles of the combustion process. In this paper, lean premixed swirl combustion of CH 4 /H 2 /CO fuel mixtures was investigated experimentally and numerically to understand the impacts of these fuels on fundamental stability phenomena such as blowoff. The swirl burner used was operated at atmospheric pressure and ambient temperature using a moderate swirl number. Different nozzles were used to determine the impact of the blends on the Central Recirculation Zones. Methane content in the fuel was decreased from 50% to 0% (by volume) with the remaining amount split equally between carbon monoxide and hydrogen. Chemical kinetic analyses were carried out using PRO-CHEMKIN to determine flame speeds and chemical properties needed for CFD calculations. Experiments were done using a Phase Locked PIV system. The Central Recirculation Zone and its turbulence were measured and correlated providing details of the structure close to blowoff. The results show how the strength and size of the recirculation zone are highly influenced by the blend, with a shift of turbulence based on carbon-hydrogen ratio, nozzles effects on the shearing flow and Re numbers. Correlation with the phenomenon was also achieved using the k-cc SST CFD model, providing more information about the impact of the CRZ and the flame turbulent nature close to the blowoff limit.

- - Using an Interactive Whiteboard to Enhance Language Teaching in Higher Education: a Libyan EFL Teacher’s Perspective: Computer assisted language learning/Applied linguistics in action. Journal of languages faculty, Tripoli University, issue 13, 2016

In this paper, we first recall the definition of a family of Koenig’s root-

finding algorithms known as Koenig’s algorithms (𝐾௣,௡) for polynomials. In the whole

paper p has degree 𝑑 ≥ 2 with real coefficients and real (and simple) zeros 𝑥௞ , 1 ≤

𝑘 ≤ 𝑑 .

Now we want to discuss Koenig’s algorithms in details where

𝑛 = 4, (𝐾௉,ସ(𝑧)).

ABSTRACT

In the 21st century, climate change is considered to be one of the greatest environmental

threats to the world, and the changes in climate extremes are estimated to have greater

negative impacts on human society and the natural environment than the changes in mean

climate.

All the IPCC's five reports between 1990 and 2013 concluded that we cannot expect stable

climate in the future and we should prepare scenarios and strategies for the survival of

humankind under the conditions of forthcoming global change.

This study presents the projections of future changes in maximum temperature events under

A2 and B2 SRES scenarios using the statistical downscaling model (SDSM) in the Zlitan

Area–Libya.

In order to explore the SDSM method, at Zlitan station in Libya has been selected as a study

site to test the methodology for maximum temperature. The study included calibration and

validate with large-scale atmospheric variables encompassing NCEP reanalysis data, the

future estimation due to a climate scenario, which are HadCM3 A2 and HadCM3 B2 . Results

of downscaling show that during the calibration and validation stage, the SDSM model can be

well acceptable regard its performance in the downscaling of daily maximum temperature.

The result of climate projection reveals that the SDSM model showed great reliability of

SDSM in ascertaining changes for the periods 2011–2040, 2041–2070 and 2071–2099,

• relative to 1961–1990 and it has very good ability to replicate the historical maximum

temperature for the observed period. Trend analysis in the study area showed an increase in

average annual and monthly maximum temperature, compared to the baseline period for both

HadCM3A2a and HadCM3B2a scenarios in both the dry and wet seasons.

However, this increase is higher in dry months than wet months for all future time horizons

and for both HadCM3A2a and HadCM3B2a scenarios. Thus there is likely to be a significant

warming in local surface temperature, which is enough for a significant change on the energy

balance and is likely to impact water availability.

Keywords: - Statistical downscaling model, SDSM, Intergovernmental Panel on Climate

Change IPCC, General circulation model, GCM, Special Report on the Emission Scenarios,

SERS, HadCM3 Hadley Research Center’s Hadley Climate Model version, Maximum

• temperature, Zlitan area, Libya.