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

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

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