Characterization of flame propagation and burning rates of various mixtures of biogas and nitrous oxide

Biogas is a potential alternative energy source with low environmental impact. However, the practical applications of biogas are relatively limited due to the existence of carbon dioxide (CO2) which acts as a diluent that decreases the calorific value and the burning rate of biogas. Nitrous oxide (N2O) is known to be a powerful oxidizing agent for propulsion applications which can enhance the combustion rate of biogas, however, there is a lack of studies that investigate the fundamental characteristics of biogas-N2O combustion. The aim of this study is to gain insight into the fundamental combustion characteristics of biogas-N2O mixtures in terms of laminar burning velocity and flame stability. In the present work, spherically expanding flames following central ignition at constant volume combustion chamber (CVCC) were employed to investigate laminar burning velocity (LBV), hydrodynamic instability, and diffusive-thermal instability of biogas-N2O mixtures at wide equivalence ratio;?, from 0.6 to 1.4, at 303K and atmospheric pressure. Two mechanisms were used in CHEMKIN-PRO 17 software in order to estimate the predicted combustion characteristics of biogas-N2O mixtures. The results indicate that the decline in LBVs was prominent in the fuel-rich mixtures than in the fuel-lean mixtures with CO2 dilution. It is found that the influence of curvature on the flame front is weakened at the fuel lean-to-stoichiometric mixture due to the decrease in the flame thickness. Therefore, flame instability tends to increase at the lean-to-stoichiometric region. The increase in CO2 in biogas by 10%, increases the Lewis number (Le) value by 3.6% to 4.6%. The diffusive-thermal instability was dominant for all biogas-N2O mixtures, as Le was less than unity throughout the entire equivalence ratio range. The thermal reaction of N2O decomposition is the most significant reaction in biogas-N2O combustion at lean mixtures of ? = 0.6 and ? = 0.8. The LBVs of biogas-N2O mixture revealed a considerable enhancement at the lean equivalence ratio of 0.8 compared to the other biogas-air mixtures with H2 addition. The effect of nitrous oxide as an oxidizer on biogas detonation characteristics is studied numerically using Chemical Equilibrium Applications (CEA) and compared with other oxidizers. Mixtures with N2O oxidant revealed 32% and 16% higher detonation pressure and detonation Mach number, respectively, at ? = 0.6, compared to that of mixtures with pure oxygen oxidant. Overall, employing N2O oxidant has enhanced the fundamental combustion characteristics of biogas significantly, which may lead to the use of biogas as a clean fuel in commercial applications that demand high combustion rates, such as power generation and aerospace

Assessment of house sparrows passer domesticus damage to single and double winter cultivations under field conditions

The ultimate goal of this study is to find out the most suitable combinations of adjacent crops that reduce house sparrows damage. The experiments were established using single and double combinations of four wintery crops. Namely, soft wheat, hard wheat, sunflower, and barley. The double cultivations were designed by growing varying crops nearby a fixed one crop as follows 1- (soft wheat alone), (soft wheat- near sunflower), ( soft wheat near – barley), and (soft wheat near – hard wheat) 2- (barley alone),(barley- near soft wheat), (barley near - hard wheat), and (barely- near sunflower) 3-(hard wheat alone),( hard wheat- near barley), (hard wheat near – sunflower), and ( hard wheat near – soft wheat). The experimental results revealed the following; the damage percentage of house sparrows to soft wheat was 25.9 %, but when grown nearby sunflower, barley, and hard wheat the soft wheat damage reached 5.9 %, 25.9 %, and 33.3 %, respectively. In single cultivation of barley, house sparrows damage was 8.2 %, but when grown nearby soft wheat, hard wheat and sunflower, the barley damage reached 13.5 %, 1.7 % and 1.2 %, respectively. Single cultivation of hard wheat house sparrows damage was 0.0 %, while when grown adjacent to barley, sunflower, and soft wheat, the hard wheat damage reached 0.0 %,0.0 % 3.8 %, respectively. In single cultivation of sunflower, house sparrows damage was 20.2 %, while when grown nearby, barley, soft wheat , and hard wheat, the sunflower damage reached 9.5 %, 10.2 % and 36.3 %, respectively. Results obtaine from this study revealed the following: 1- sunflower could be grown nearby barley and / or soft wheat, but away from hard wheat; 2- barley could be grown nearby sunflower and /or soft wheat, but away from hard wheat; 3- soft wheat could be grown nearby sunflower, but away from hard wheat; 4- hard wheat could be grown nearby barley or sunflower, but away from soft wheat. These concomitant cultivations can be successfully practiced be small growers to protect their main crops from house sparrows attack naturally and effectively without using any pest control compounds and without any extra costs as well

Transitional governments and the protection of foreign investments under international law

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University Londo

Evaluation of Certain Synthetic and Natural Pesticides Against Whitefly Bemisia tabaci (Genn.) on Green Bean and Effect on Honeybee Apis mellifera L.

The green bean crop (Phaseolus vulgaris) is infested with many insects such as whiteflies (Bemisia tabaci). An investigation was carried out to study the insecticidal activity of whitefly (Bemisia tabaci), five pesticides were used, namely Thiamothoxam, Sulfoxaflor, Spirotetramat, Pymetrozine, and Flonicamid, and three commercial natural pesticides, namely Superrego, Topnine, and Bernastar. Pesticides and natural pesticides were sprayed during the two seasons of 2020 and 2021. The obtained results in terms of the reduction rate of the insects' number were as follows: The highest rate of reduction appeared in Thiamothoxam and Sulfoxaflor treatments, where it reached above 80%, while the other pesticides were in the range of 40% to 60%, and the lowest reduction rate was 34.33% and 36.00 % for Bernastar during season 2020 and 2021 respectively. When evaluating the toxicity of these pesticides and natural pesticides against honeybees (Apis mellifera), the pesticides did not reveal any toxicity to honeybees, except for Thiamothoxam, Sulfoxaflor, and Superrego The LC50 and LD50 values against honeybees were 0.2 ppm and 0.000005µg/one honeybee for Thiamothoxam, 4.5 ppm and 0.0001125 µg/one bee for Sulfoxaflor, and 0.95 ppm and 0.00002375 µg /one bee for Superego respectively

The Impact of the Implementation of Safety Measures on Frontline Workers’ Safety Accountability: A Saudi Arabian Case Study of a Well Intervention Business Model

Even in the best-case scenarios, working in the energy sector is tough because of the numerous possible risks that can arise during routine tasks. Therefore, the top priority of firms’ management is their responsibilities for their employees’ safety as they undertake various roles. In this study, the researchers investigated the effect of safety measures on the safety accountability (SA) of the Saudi Arabian Aramco Company’s frontline workers. The researchers used a quantitative approach and collected data through a survey questionnaire. We applied a random sampling technique to target the company’s frontline workers. Initially, the researchers distributed 450 questionnaires and received back 242 valid samples. This represented a 53% response rate. Next, the researchers applied Structural Equation Modeling (SEM) to assess the directions of the hypothesized paths. This study’s findings demonstrate that safety policy (SP), safety training (ST), safety communication (SC), safety commitment (SCT) and safety incentives (SIs) have positive and significant effects on frontline workers’ safety accountability (SA). In addition, this study’s findings provide guidelines to policy makers, government authorities and company heads to implement further initiatives that adopt precautionary and safety measures to protect their frontline workers’ lives. Further, this study’s findings show the benefits of opening avenues of research to concentrate on safety measures such SP, ST, SC, SCT and SIs in order to create the frontline workers’ responsibilities for safety accountability (SA). Finally, the empirical evidence, which the researchers obtained from the Aramco Company’s frontline workers, adds to the depth of knowledge on this subject; validates the environmental science and management literature; and provides road maps for other companies to investigate safety challenge

The Impact of the Implementation of Safety Measures on Frontline Workers’ Safety Accountability: A Saudi Arabian Case Study of a Well Intervention Business Model

Even in the best-case scenarios, working in the energy sector is tough because of the numerous possible risks that can arise during routine tasks. Therefore, the top priority of firms’ management is their responsibilities for their employees’ safety as they undertake various roles. In this study, the researchers investigated the effect of safety measures on the safety accountability (SA) of the Saudi Arabian Aramco Company’s frontline workers. The researchers used a quantitative approach and collected data through a survey questionnaire. We applied a random sampling technique to target the company’s frontline workers. Initially, the researchers distributed 450 questionnaires and received back 242 valid samples. This represented a 53% response rate. Next, the researchers applied Structural Equation Modeling (SEM) to assess the directions of the hypothesized paths. This study’s findings demonstrate that safety policy (SP), safety training (ST), safety communication (SC), safety commitment (SCT) and safety incentives (SIs) have positive and significant effects on frontline workers’ safety accountability (SA). In addition, this study’s findings provide guidelines to policy makers, government authorities and company heads to implement further initiatives that adopt precautionary and safety measures to protect their frontline workers’ lives. Further, this study’s findings show the benefits of opening avenues of research to concentrate on safety measures such SP, ST, SC, SCT and SIs in order to create the frontline workers’ responsibilities for safety accountability (SA). Finally, the empirical evidence, which the researchers obtained from the Aramco Company’s frontline workers, adds to the depth of knowledge on this subject; validates the environmental science and management literature; and provides road maps for other companies to investigate safety challenge

Synthetic Analogs of Marine Alkaloid Aplysinopsin Suppress Anti-Apoptotic Protein BCL2 in Prostate Cancer

Aplysinopsins are a class of indole alkaloids that possess various pharmacological activities. Although their action has been studied in regard to many diseases, their effect on prostate cancer has not yet been examined. Therefore, we synthesized a new series of aplysinopsin analogs and investigated their cytotoxic activity against prostate cancer. Five analogs showed high antitumor activity via suppressing the expression of the anti-apoptotic gene Bcl2, simulationously increasing the expression of the pro-apoptotic genes p53, Bax and Caspase 3. The inhibition of BCL2 led to the activation of BAX, which in turn activated Caspase 3, leading to apoptosis. This dual mechanism of action via apoptosis and cell cycle arrest induction is responsible for aplysinopsin analogs antitumor activity. Hence, our newly synthesized analogs are highly promising candidates for further preclinical studies against prostate cancer

Effect of adding systematic desensitization to goal-directed paradigm on risk of falling in patients with stroke: a randomized controlled trial

BackgroundImprovement in rehabilitation outcomes for patients suffering from chronic stroke can be attained through systematic desensitization of their fear of falling, which in turn reduces the risk of falling.PurposeThis study aimed to examine the effect of adding systematic desensitization to a goal-directed paradigm on functional performance, balance, risk of falling, and fear of falling among chronic ischemic stroke patients.MethodologyTwo equally sized groups, each comprising 40 stroke patients of both sexes, were randomly divided. For 8 weeks, Group A received three sessions per week of combined treatment consisting of systematic desensitization and a goal-directed paradigm, while Group B received only the goal-directed paradigm. The Timed Up and Go (TUG) test and Dynamic Gait Index (DGI) were used to assess function performance; the Berg Balance Scale (BBS) and the Biodex Fall Risk Index (FRI) were used to evaluate balance; and the 16-item Fall Efficacy Scale-International (FES-I) was used to evaluate fear of falling. At baseline and after the treatment, all measurements were obtained.ResultsBoth groups (A and B) revealed a substantial increase in functional performance through a decrease in TUG scores and an increase in DGI. Additionally, there was a decrease in the risk of falling through an increase in the BBS scores and a decrease in the FRI. Furthermore, there was a decrease in the fear of falling, as measured using the FES-I, after treatment, with superior improvement in Group A with a p-value of <0.001.ConclusionSystematic desensitization combined with a goal-directed paradigm has a superior effect on improving functional performance and reducing the risk of falling and the fear of falling in patients with stroke compared to a goal-directed paradigm alone