Kinetic Modelling for Tar Evolution and Formation in a Downdraft Gasifier

Biomass gasification modeling is a powerful tool used to optimize the design of a gasifier. A detailed kinetic model was built by the current authors [1] to predict the behavior of air blown downdraft gasifier for a wide range of materials within the range of (38≤C≤52) %, (5.2≤H≤7) %, and (21.7≤O≤45) %. The model was verified and showed a good stability for a wide range of working parameters like equivalence ratio and moisture content. In the current research, 4 main tar species are added to the model to represent tar formation using detailed kinetic reactions. The yield of tar species is discussed for different zones of a gasifier based on temperature of each zone. Mass and energy balance are calculated. 18 different kinetic reactions are implemented in the kinetic code to predict the optimum working conditions that leads to the production of higher value producer gas. Results conclude that using ER of 0.3 with moisture content levels lower than 10% will lead to the production of higher yields of syngas with lower amounts of tar

Single laser light source multi-channel PSK optical communication

Two light waves which have same wavelength and same plane of polarization can interact with each other and produce interference pattern only if the path difference between two waves is less than coherent length. It also means that if path difference is more than coherent length then waves will not create interference pattern or decoding of signal will not be possible. Using this property, it was demonstrated that more than one channel can be transmitted as long as the difference in their path lengths is more than the coherence length of the light source used. © 2006 Asian Network for Scientific Informatio

Nematodes associated with soybean (Glycine max) in upper Egypt

Dix-sept espèces de nématodes phytoparasites ont été récoltées dans les champs de soja des Gouvernorats de Menia, Assiut et Sohag, en Haute Egypte. Les espèces #Helicotylenchus pseudorobustus, Longidorus pisi, Pratylenchoides ritteri, P. variabilis, rotylenchulus parvus et #Tylenchorhynchus annulatus sont signalées pour la première fois en Egypte. #Merlinius brevidens est rencontré avec une fréquence relativement élevée tandis que #Pratylenchus zeae est présent en populations assez denses. #Meloidogyne javanica, M. incognita, Pratylenchus zeae, H. pseudorobustus, R. parvus et #Xiphinema sp. pourraient également avoir une grande importance dans les champs de soja de Haute Egypte. Les populations de #Meloidogyne javanica et #M. incognita sont plus élevées dans les sols sableux que dans les sols sablo-argileux ou argileux. #Pratylenchus zeae et #M. brevidens sont présents en populations élevées dans les trois types de sol, et plus particulièrement dans les sols sableux. Les populations de #H. pseudorobustus sont relativement élevées dans les sols argileux, tandis que pour #R. parvus les sols sablo-argileux sont plus favorables. (Résumé d'auteur

Vibration Control in MEMS Resonator Using Positive Position Feedback (PPF) Controller

In this paper, the vibration of a micro-electromechanical resonator with positive position feedback controller is studied. The analytical results are obtained to the first order approximation by using the multiple scale perturbation technique. The stability of the steady-state solution is presented and studied applying frequency response equations near the simultaneous primary and internal resonance cases. The effects of the controller and some system parameters on the vibrating system are studied numerically. The main result of this paper indicates that it is possible to reduce the vibration for the resonator system

Digestibility and rumen fermentation of a high forage diet pre-treated with a mixture of cellulase and xylanase enzymes

El articulo esta publicado en una revista de Open accessForages play an important role in ruminant animal production worldwide. Unlocking the nutritional potential of poor-quality tropical forages with fibrolytic enzymes would improve forage digestibility and utilization. Using in vitro and in vivo methods this study investigated the effect of pre-treating Smutsfinger hay for 24 hours with a mixture of fibrolytic enzyme (100% cellulase; 75% cellulase: 25% xylanase; 50% cellulase: 50% xylanase; 25% cellulase: 75% xylanase; 100% xylanase and a control with no enzyme) on ruminal fermentation and digestibility of nutrients by sheep. For in vitro fermentation, dry matter, neutral detergent fibre (NDF) degradability and volatile fatty acids (VFA) were determined with standard procedures. The same treatments were used for an in vivo digestibility trial using Merino sheep in a 6 x 6 Latin square design. Feed intake and total tract digestibility were recorded. Rumen fluid samples were collected daily, preserved, and analysed for VFA. The addition of 100% cellulase enzyme to Smutsfinger hay in vitro increased (P <0.05) NDF degradability and gas production compared with the control and inclusion of 100% xylanase enzyme. Both 100% cellulase and xylanase enzymes significantly reduced in vitro end time fermentation pH. A 50:50 mixture of cellulase and xylanase plus enzyme in vivo, increased acetate, total VFA concentration, and higher NDF and ADF digestibility of the test feed compared with the control. Inclusion of a 50-75% mixture of cellulase and 50-25% xylanase enzymes treatment led to higher gas production and butyrate concentration, decreased ruminal pH and improved nutrient digestibility

Azzawi Dates (Phoenix dactylifera) as a Substitute for Corn as an Energy Source in Sheep Diet: In vitro Gas Production and Fermentation

In vitro gas production technique was used in the current study to evaluate Azzawi date (AD) as a substitute for corn grain (CG). The AD was used to replace corn grain at graded levels in the proportion: 0:100 (CG), 25:75 (AD25), 50:50 (AD50), 75:25 (AD75), and 100:0 (AD100). Gas production (GP) was continuously measured by incubating samples in buffered rumen fluid from cannulated sheep and it was recorded at 3, 6, 9, 12, 24, 48 and 72h of incubation. Cumulative GP, kinetics of GP (a, b and c), ammonia nitrogen (NH3-N) and volatile fatty acids (VFA) concentrations were determined, while metabolizable energy (ME), net energy (NE), organic matter digestibility (OMD), microbial protein (MP) were estimated. The gas volume was increased (P<0.05) at 12h with increasing the substitution levels of AD in the feed, the values ranged between 31.3 and 44.7 ml/200 mg DM. However, it was found to be decreased (P<0.05) at 48 and 72h with increasing substitution levels of AD. There were no differences in the gas production found at 24h. Data of VFA, NE, OMD and MP were similar (P>0.05) among the feeds. The energy (ME; MJ/kg DM) value of AD25 (10.4) and AD50 (10.3) were comparable to that of CG (10.5); however it was reduced (P<0.05) with AD75 and AD100. Data demonstrated that, Azzawi date at the level of 50 g/100g of substrate (i.e., AD50) may have similar energy contents as of corn grain, and it can be used as a source of energy in ruminant diets either alone or in combination with corn grain

Anti-corruption disclosure quality and earnings management in the United Kingdom: the role of audit quality

Purpose Building upon institutional pressures on firms to deal with corruption, this study aims to investigate the association between a firm's engagement with anti-corruption disclosure quality (ACD_Q) and earnings management (EM). Also, this study examines the moderating role of audit quality in the association between ACD_Q and EM. Design/methodology/approach The authors constructed an ACD_Q index based on the 2010 UK Bribery Act and taking into account a wide range of rules on corruption and bribery, including those of the OECD, World Bank, UNCTAD, UNGC, UNCAC and GRI. Generalized method of moments and panel regression were used to examine the association between ACD_Q and EM. Findings Using a sample of 2,695 firm‐year observations of the UK’s FTSE-350 from 2008 to 2018, this study finds ACD_Q is negatively associated with EM. In addition, this negative relationship is contingent on audit committee independence and audit committee expertise. This finding is supported by additional robustness and sensitivity analysis. Practical implications The empirical evidence reiterates the crucial need for more concerted efforts to ensure corporate engagement in anti-corruption practices with a view to reducing earnings manipulations. Originality/value This study contributes to the limited evidence that investigates how ACD Q influences EM in the UK after the introduction of the UK Bribery Act in 2010. Furthermore, by considering the period from 2008 to 2019, this study investigates the potential moderating role of UK corporate governance reforms in EM reduction. In particular, to the best of the authors’ knowledge, this study assesses for the first time the moderating effect of audit committee mechanisms on the ACD Q and EM nexus

Hot red pepper powder as a safe alternative to antibiotics in organic poultry feed: An updated review

Globally, several studies have investigated the utilization and efficacy of promising medicinal herbal plants to enhance livestock and poultry production. The most commonly investigated phytobiotics in broiler ration were oregano, garlic, thyme, rosemary, black pepper, hot red pepper (HRP), and sage. Phytobiotics are classified on the basis of the medicinal properties of plants, their essential oil extracts, and their bioactive compounds. The majority of bioactive compounds in plants are secondary metabolites, such as terpenoids, phenolic, glycosides, and alkaloids. The composition and concentrations of these bioactive constitutes vary according to their biological factors and manufacturing and storage conditions. Furthermore, HRP is one of the most important and widely used spices in the human diet. Capsicum annum, that is, HRP, is a species of the plant genus Capsicum (pepper), which is a species native to southern North America and northern South America and is widely grown and utilized for its fresh or cooked fruits. Moreover, these fruits may be used as dried powders or processed forms of oleoresins. Researches have proven that C. annuum is the only plant that produces the alkaloid capsaicinoids. Approximately 48% of its active substances are capsaicin (8-methyl-N-vanillyl-6-nonemide), the main active compound responsible for the intense effects of HRP varieties and the main component inducing the hot flavor. This review aimed to highlight the effects of HRP as a phytobiotic in broiler nutrition and its mode of action as a possible alternative to antibiotics and clarify its impact on broiler and layer productivity

Does the quality of voluntary disclosure constrain earnings management in emerging economies? Evidence from Middle Eastern and North African banks

Purpose This study aims to examine the influence of the quality of voluntary disclosure (QVD) on earnings management (EM) amongst a sample of commercial banks in the Middle East and North Africa (MENA) region. Design/methodology/approach Using a sample of 1,060 bank-year observations for the period 2006–2015, this paper developed a three-dimensional framework to measure the QVD, which considers the quantity, spread and usefulness of the information. Furthermore, this study examines the QVD-EM nexus using an ordinary least squares regression model. This technique is supplemented with conducting an instrumental variable regression model and a two-stage least squares model to overcome the potential occurrence of endogeneity problems. Findings The findings suggest that QVD is negatively attributed to EM in the context of MENA banks. The findings also confirm that the quality of financial reporting is enhanced by QVD dimensions that were considered in the framework, leading banks to less engagement in EM practices. In contrast, the influence of the quantity dimension (level) of the disclosed information has an insignificant impact on EM, while the spread and usefulness dimensions of VD are negatively and significantly associated with EM in the region. Research limitations/implications Although the results are robust to various measurements and to the possible occurrence of endogeneity problems, there are a few limitations should be acknowledged, which provides opportunities for future research. For example, the sample size is relatively small due to data accessibility issues. Likewise, the findings of the research might not be appropriate for non-financial sectors. These limitations provide a good opportunity for future studies to expand on the research by covering other developing economies and, thereby, enriching the understanding offered by this study. Practical implications This study offers several implications for bank managers, academics and policymakers. Firstly, it may help managers to appreciate the function and the importance of QVD in mitigating EM. Secondly, for academics, the study provides suggestive evidence on the impact of QVD on EM; however, future research may need to consider the role of morality and ethical behaviour across different environments in reducing excessive risk-taking and constraining earnings manipulation. Finally, it provides insights for policymakers and regulators to develop a framework or guidance that can help banks in providing high-QVD in the context of developing economies. Originality/value The study distinctively develops an innovative measurement for QVD using a new multi-dimensional model. This paper also bring new evidence on QVD complexity and its impact on EM practice from an under-researched developing context, namely, the MENA region

Two-Loop Calculation of the Anomalous Exponents in the Kazantsev--Kraichnan Model of Magnetic Hydrodynamics

The problem of anomalous scaling in magnetohydrodynamics turbulence is considered within the framework of the kinematic approximation, in the presence of a large-scale background magnetic field. Field theoretic renormalization group methods are applied to the Kazantsev-Kraichnan model of a passive vector advected by the Gaussian velocity field with zero mean and correlation function $\propto \delta(t-t')/k^{d+\epsilon}$. Inertial-range anomalous scaling for the tensor pair correlators is established as a consequence of the existence in the corresponding operator product expansions of certain "dangerous" composite operators, whose negative critical dimensions determine the anomalous exponents. The main technical result is the calculation of the anomalous exponents in the order $\epsilon^2$ of the $\epsilon$ expansion (two-loop approximation).Comment: Presented in the Conference "Mathematical Modeling and Computational Physics" (Stara Lesna, Slovakia, July 2011