A new DBD microplasma burner for measuring the effect of nanosecond discharge on burning velocity of CH4-Air flame at atmospheric pressure

Using of non-equilibrium plasma for ignition, combustion and high speed flow applications are rapidly developing in the last decades due to its ability to produce a large amount of radicals and excited species which has a great potential in flame stabilization and emission control. Although many studies have demonstrated the effectiveness of plasma to enhance combustion properties, the detailed enhancement mechanism is still highly unknown. Toward a better understanding of the flame behaviour under plasma effect, a novel micro-plasma reactor has been developed to generate a non-thermal plasma discharge in atmospheric pressure. In addition, a laboratory scale burner has been constructed to utilize the plasma reactor to stabilize lean premixed methane/air flame where the mixture reacts efficiently with the plasma species in the micro-plasma reactor. Nano-second high voltage plasma discharge in different frequencies ranging from 0 to 15 kHz and different equivalence ratios have been studied. Emission spectroscopic measurements has been utilized to figure out the effect of the plasma on the combustion chemistry. Temperature measurements by Rayleigh scattering method to show the thermal effect of the plasma discharge on flame temperature. It is clear that the burning velocity increases as a result of using plasma discharge. Form the emission spectroscopic measurements, an increased amount of (OH) and (CH) radical have been observed. <br/

A New Log Lindley Distribution with Applications

This paper introduces a new generalization of the Lindley distribution introduced by [1], using the basic idea of [2] and along the lines of [3]. The new distribution is a compound of the Lindley and logarithmic distributions. We refer to the new model as the logarithmic-Lindley (Log-L) distribution. This model is capable of modeling various shapes of aging and failure criteria. The properties of the Log-L model are discussed, and the maximum likelihood estimation method is used to evaluate the parameters involved. Finally, the usefulness of the new model for modeling reliability data is illustrated using a two real data sets with simulation study

The Use of Cubic Splines in the Numerical Solution of Fractional Differential Equations

Fractional calculus became a vital tool in describing many phenomena appeared in physics, chemistry as well as engineering fields. Analytical solution of many applications, where the fractional differential equations appear, cannot be established. Therefore, cubic polynomial spline-function-based method combined with shooting method is considered to find approximate solution for a class of fractional boundary value problems (FBVPs). Convergence analysis of the method is considered. Some illustrative examples are presented

Burning velocity measurement of lean methane-air flames in a new nanosecond DBD microplasma burner platform

This paper presents the initial characterization of a new burner design to study the effect of non-thermal plasma discharge on combustion characteristics at atmospheric pressure. The burner allows stabilizing an inverted cone flame in a mixture flowing through a perforated plate designed as a microplasma reactor. The design principle of the microplasma reactor is based on the dielectric barrier discharge scheme which helps to generate a stable nonthermal plasma discharge driven by nanosecond high-voltage pulses in the burner holes. The consumed power and pulse energy have been calculated from simultaneously measurements of current and voltage of the electrical pulses. Time-resolved measurements of direct emission spectra for nitrogen second positive system N2(C-B) have been done to determine the rotational and vibrational temperatures of the plasma discharge. By fitting the spectra with SPECAIR simulation data, it was found that the rotational and vibrational temperatures are 480 K and 3700 K, respectively, for the discharge in methane-air mixture with an equivalence ratio of 0.5 at atmospheric pressure. The influence of a high-voltage (5 kV) pulsed nanosecond discharge on the laminar burning velocity of methane-air flame has been investigated over a range of equivalence ratios (0.55–0.75). The laminar burning velocity was calculated by the conical flame area method which has been validated by other published data. CH* chemiluminescence image analysis has been applied to accurately determine the flame area. The results show an increase of the burning velocity of about 100% in very lean (Φ= 0.55) flames as a result of the plasma discharge effect

Worldwide reduction in MERS cases and deaths since 2016

Since 2012, Middle East respiratory syndrome (MERS) coronavirus has infected 2,442 persons worldwide. Case-based data analysis suggests that since 2016, as many as 1,465 cases and 293–520 deaths might have been averted. Efforts to reduce the global MERS threat are working, but countries must maintain vigilance to prevent further infections

Genital-Sparing Cystectomy versus Standard Urethral-Sparing Cystectomy Followed with Orthotopic Neobladder in Women with Bladder Cancer: Incidence and Causes of Hypercontinence with an Ultrastructure Study of Urethral Smooth Muscles

BACKGROUND: Bladder cancer in women is an indication for radical cystectomy (RC) when the tumour is confined muscle-invasive bladder cancer (MIBC) of T2 N0M0, or high risk progressive non-muscle invasive bladder cancer (NMIBC). Radical cystectomy is either genital-sparing cystectomy (GSC) or standard urethra-sparing cystectomy (USC) that is followed with orthotopic ileal neobladder (ONB). Post-operative chronic retention “Hypercontinence†had been reported in different series following URS or GSC and ONB. In long-term follow-up, we evaluated the functional outcome of women who developed hypercontinence after USC or GSC and ONB. AIM: An ultrastructure study of female urethral smooth muscle was done to elucidate the underlying causes of hypercontinence. MATERIAL AND METHODS: Retrospective study was conducted on 71 women who underwent RC and ONB, 45women had undergone USC, and 26 women had GSC, follow-up ranged from 5 to 15 years. Ultrastructure studies were done on 5 urethral biopsy specimens from 5 women who had hypercontinence, and 4 biopsies were from a normal control. RESULTS: Follow-up showed that women who had undergone USC and ONB, 28.88% developed hypercontinence, where in the series of GSC and ONB three women out of 26 developed hypercontinence (7.80%). Three women who had hypercontinence following USC and ONB, they developed stones in the ileal pouch. Ultrastructure study of urethral smooth muscles in women who had hypercontinence showed organized collagen fibrils, absent myelin sheath, and non-detected lymphatic vessels. Normal urethra showed collagen fibrils within the interstitial matrix, preserved myelin sheath of nerve fibres, the presence of lymphatic vessels in the matrix. CONCLUSION: The present study shoes that GSC with ONB leads to the minimal incidence of hypercontinence (7.80%), while standard USC lead to higher incidence (28.88%). Ultrastructure changes of the female urethra who had hypercontinence were fibrotic changes, loss of myelin sheath and minimal vascularity, their findings explains the underlying cause of hypercontinence and support the technique of GSC rather than the standard USC

Investigation of Crystal Structure, Electrical and Magnetic Properties of Spinel Mn-Cd Ferrite Nanoparticles

Cd1 − xMnxFe2O4 (x = 0, 0.25, 0.5, 0.75, 1) spinel ferrite nanoparticle samples were synthesized using a flash auto-combustion technique and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The inspection of dielectric and magnetic properties of the prepared ferrites was carried out by using broadband dielectric spectroscopy (BDS) and vibration sample magnetometer (VSM) measurements, respectively. X-ray diffraction analysis verified the formation of the main cubic phase with space group Fd3m and a decrease in lattice constants with the increase in Mn-content. FTIR study revealed the two characteristic absorption bands of spinel ferrites and their dependence on Mn-content was investigated and explained. Elastic moduli, bulk modulus, rigidity modulus, Young modulus, and calculated Debye temperature have been studied and found to decrease with the increase in Mn-content. SEM analysis revealed nanoparticles agglomeration of uniform grains with increasing in the average grain size as Mn-content increased. The VSM measurements showed an increase in saturation magnetization accompanied by a decrease in coercivity as Mn-content increased. Dielectric investigations showed very high values of permittivity and dielectric loss at lower frequencies (between 105 and 106 @ 0.1 Hz according to the manganese content) reflecting the combination of exchange of electrons between ferrous and ferric ions and ions’ transport. The ac-conductivity showed a plateau that yields the dc-conductivity at lower frequencies followed by a characteristic frequency at which it tends out to follow a power law. The relation between these two parameters confirms the empirical BNN-relation. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature