A B S T R A C T

Swirl stabilised combustion is one of the most successful technologies for flame stabilisation in gas turbine combustors. Lean premixed combustion systems allow the reduction of NOx coupled with fair flame stability. The swirl mechanism produces an aerodynamic region known as central recirculation zone (CRZ) providing a low velocity

region where the flame speed matches the flow velocity, thus anchoring the flame whilst serving to recycle heat and active chemical species to the root of the former. Another beneficial feature of the CRZ is the enhancement of the mixing in and around this region. However, the mixing and stabilisation processes inside of this zone have shown to be extremely complex. The level of swirl, burner outlet configuration and combustor expansion are very important variables that define the features of the CRZ. The complex fluid dynamics and lean conditions pose a problem for stabilization of the flame. The

problem is even more acute when alternative fuels are used for flexible operation.

Therefore, in this paper swirling flame dynamics are investigated using computational fluid dynamics (CFD) with commercial software (ANSYS). A new generic swirl burner operated under lean-premixed conditions was modelled. A variety of nozzles were analysed using isothermal case to recognize the the behavers of swirl.

The investigation was based on recognising the size and strength of the central recirculation zones. The dimensions and turbulence of the Central Recirculation Zone were measured and correlated to previous experiments. The results show how the strength and size of the recirculation zone are highly influenced by both the shear layer surrounding the Central

Recirculation Zones (CRZ) and outlet configurations.

Abstract: In this work, we consider linear and nonlinear Volterra integral equations of the second kind. Here, by converting integral equation of the first kind to a linear equation of the second kind and the ordinary differential equation to integral equation we are going to solve the equation easily. The Adomian decomposition method or shortly (ADM) is used to find a solution to these equations. The Adomian decomposition method converts the Volterra integral equations into determination of computable components. The existence and uniqueness of solutions of linear (or nonlinear) Volterra integral equations of the second kind are expressed by theorems. If an exact solution exists for the problem, then the obtained series convergence very rabidly to that solution. A nonlinear term F(u) in nonlinear volterra integral equations is Lipschitz continuous and has polynomial representation. Finally, the sufficient condition that guarantees a unique solution of Volterra (linear and nonlinear) integral equations with the choice of the initial data is obtained, and the solution is found in series form. Theoretical considerations are being discussed. To illustrate the ability and simplicity of the method. A few examples including linear and nonlinear are provided to show validity and applicability of this approach. The results are taken from the works mentioned in the reference. 

Neurodegenerative disorders results in inflammatory processes, including inflammatory cytokine secretion and concomitant superoxide production. Acetylcholinesterase inhibitors (AChEIs) influence neuro degeneration through anti-inflammatory effects. Donepezil as an AChEIs also provide neuro protection. This study aimed to evaluate the effect of donepezil (DZ) as a potent acetyl-cholinesterase (AChE) inhibitor, L-NG-Nitroarginine methyl ester (L.NAME) as non-selective nitric oxide synthase inhibitor and 7-nitroindazole (7-NI) as a selective neuronal nitric oxide synthase (NOS) inhibitor against Amyloid beta-peptide (1-42) (Aβ(1-42)) induced neurological disorder. Rats were divided into six groups including control, Aβ(1-42) ,Aβ(1-42) +L-arginine, Aβ(1-42) +L-NAME ,Aβ(1-42) +7-NI, and Aβ(1-42) +DZ. Brain AChE, malondialdehyde, nitric oxide, super oxidedismutase, catalase, reduced glutathione, interleukin 1-beta (IL-1β) and tumor necrosis factor alpha (TNF-α) were measured. Also, brain fatty acids fractions were estimated by high performance liquid chromatography (HPLC). Aβ(1-42) significantly alter levels of brain antioxidant, inflammatory markers and fatty acids content compared to the control group. Treatment with L.NAME, 7-NI and especially DZ improve these parameters. Administration of acetylcholinesterase inhibitors such as DZ attenuates neurodegenerative disorders through decreasing oxidation and inflammation.

Keywords: Neurotoxicity, Aβ (1-42), Donepezil, Nitric oxide, 7-nitroindazole, Fatty acids, HPLC

Corruption is widespread in different regions in the world and exists in all countries, both

developed and undeveloped, in the public and private sectors. Just the rate of corruption is

different from one country to another. Corruption is a very important issue in the world today,

and it is very important to understand causes of corruption across the nations. Thus, corruption

has occupied minds of thinkers on different levels both political and economic. It can be a major

obstacle in the process of economic development. Hence, corruption has negative impacts on the

economic growth in any country that suffers from it. Thinkers seek different ways to diagnose

reasons for corruption, and they try to find a panacea to this problem because corruption impedes

the development of countries.

Genetically encoded calcium indicators (GECIs) have gained widespread use for measurement of neuronal activity but their low expression levels in transgenic mice tend to limit sensitivity. We have developed a transgenic mouse line (SyG37) that expresses a ratiometric calcium sensor, SyGCaMP2-mCherry, that is expressed throughout the brain but targeted to presynaptic terminals. Within the CA1 and CA3 regions of hippocampus of male and female mice, SyGaMP2 fluorescence responds linearly up to 10 electrical stimuli at frequencies up to 100 Hz and it can detect responses to a single stimulus. Responses in single boutons can be measured using multiphoton microscopy. The ensemble amplitude of SyGCaMP2 responses is a function of the number of stimuli applied and the number of contributing boutons. The peak responses and initial rates of calcium influx in single boutons in CA1 and CA3 were similar but the rate of calcium clearance from CA3 boutons after stimulation was significantly faster. In CA1, DNQX reduced SyGCaMP2 responses to Schaffer collateral stimulation to 86% of baseline indicating that 14% of the total response originated from presynaptic terminals of neurones synaptically driven via AMPA receptors. Theta burst stimulation induced long-term potentiation (LTP) of both SyGCaMP2 and fEPSP responses in both young and 18-month-old mice. The proportion of postsynaptically connected terminals increased significantly to 76% of the total after LTP induction. The SyG37 mouse allows stable optical detection of synaptic activation and connectivity at the single bouton level and can be used to characterize the contributions of presynaptic calcium to synaptic transmission and plasticity.

This research paper was motivated by the observation that exams are the main (if not the sole) method of assessment in the postgraduate programs in the English departments in the University of Zawia and the Libyan Academy. The aim was investigating and experimenting the use of assignment as another method of assessing students’ achievement.

To fulfill this aim, the researcher taught the students in the two English departments separately and simultaneously one of the subjects, namely ELT Methodology. Instead of giving them a typical midterm exam, students were asked to do an assignment in which they evaluate the suitability of some textbooks in teaching and learning English as a foreign language and adapt these books to be suitable for the Libyan context. The same students were given a formal and final exam at the end of the course. The comparison of the scores of the two assessment methods has shown that students did better in the assignment than in the exam. This has supported the results of the questionnaire which was given to the same students. These results indicated that half of the students preferred using assignments to using exams while another considerable number preferred the use of a mixture of assignments and exams. Only a few students selected exams as their preferred method of assessment.

Therefore, it is recommended that assignment as a method of assessing students achievement should be integrated into MA programs in Libyan universities and academies due to its role in improving the students’ practical skills and abilities and enhancing their understanding of the learned subjects.