Shock-turbulence interactions in a reacting flow

A specific reactive flow configuration, the interaction of a detonation wave with convected homogeneous isotropic weak turbulence (which can be constructed by a Fourier synthesis of small amplitude shear waves) is addressed. The effect of chemical heat release on the rms fluctuations downstream of the detonation is presented as a function of Mach number. In addition, for the particular case of the von Karman spectrum, the one dimensional power spectra of these flow quantities is given

The analysis and simulation of compressible turbulence

Compressible turbulent flows at low turbulent Mach numbers are considered. Contrary to the general belief that such flows are almost incompressible, (i.e., the divergence of the velocity field remains small for all times), it is shown that even if the divergence of the initial velocity field is negligibly small, it can grow rapidly on a non-dimensional time scale which is the inverse of the fluctuating Mach number. An asymptotic theory which enables one to obtain a description of the flow in terms of its divergence-free and vorticity-free components has been developed to solve the initial-value problem. As a result, the various types of low Mach number turbulent regimes have been classified with respect to the initial conditions. Formulae are derived that accurately predict the level of compressibility after the initial transients have disappeared. These results are verified by extensive direct numerical simulations of isotropic turbulence

The analysis and modeling of dilatational terms in compressible turbulence

It is shown that the dilatational terms that need to be modeled in compressible turbulence include not only the pressure-dilatation term but also another term - the compressible dissipation. The nature of these dilatational terms in homogeneous turbulence is explored by asymptotic analysis of the compressible Navier-Stokes equations. A non-dimensional parameter which characterizes some compressible effects in moderate Mach number, homogeneous turbulence is identified. Direct numerical simulations (DNS) of isotropic, compressible turbulence are performed, and their results are found to be in agreement with the theoretical analysis. A model for the compressible dissipation is proposed; the model is based on the asymptotic analysis and the direct numerical simulations. This model is calibrated with reference to the DNS results regarding the influence of compressibility on the decay rate of isotropic turbulence. An application of the proposed model to the compressible mixing layer has shown that the model is able to predict the dramatically reduced growth rate of the compressible mixing layer

Volatile metabolites profiling to discriminate diseases of tomato fruits inoculated with three toxigenic fungal pathogens

The volatile metabolites of tomato fruits inoculated with three toxigenic fungi isolated from spoilt tomatoes were profiled using gas  chromatography/mass spectrometry. Differences in the number and  amount of volatile metabolites were observed. The study yielded a total of 52 different volatile metabolites. Healthy ripe tomato fruits yielded  twenty-eight metabolites predominated among them were oleic acid amide (10.89%), 9-octadecenoic acid (9.83%), methyl cis-9-octadecenoate (7.73%), and the least was 2, 3-Heptanedione (0.32%). Tomato fruits inoculated with A. niger yielded 11; A. flavus yielded 15 different volatile metabolites while that inoculated with F. oxysporum yielded 8 volatile  metabolites. Among them only 5 volatile metabolite occurred relatively consistent in fruits inoculated with A. niger and A. flavus while adogen 73  and 9-Octadecenoic acid (Z) occurred relatively consistently in fruits  inoculated with the three fungi. Hexadecanoic acid and 6-Methyl-2,4-di - tert - butyl – phenol was common in fruits inoculated with F. oxysporum and A. niger with that of A. niger having the highest value (9.67%) for Hexadecanoic acid while fruits inoculated with F. oxysporum had highest (2.66%) for 6-Methyl-2,4-di - tert - butyl – phenol. Ten metabolites were  unique to A. flavus while A. niger and F. oxysporum had 4 metabolites unique to each of them. This study suggests that these unique metabolites can be used as biomarkers to detect tomato diseases/pathogen or toxigenic fungi at an early stage of disease progression and to manage tomato diseases in storage and outbreak of food borne disease, after further validation under commercial conditions

YIELD AND YIELD CHARACTERS OF SORGHUM (Sorghum bicolor L. Moench )VARIETIES AS INFLUENCED BY IRRIGATION INTERVAL AND PLANT DENSITY AT KADAWA IN THE SUDAN SAVANNAH

A two-years field experiment was conducted during 2008 and 2009 dry seasons at Irrigation ResearchStation Kadawa in the Sudan savannah to study the yield and yield characters of sorghum (Sorghumbicolor L. Moench) varieties as influenced by irrigation intervals and plant densities. The treatmentsconsisted of factorial combination of three sorghum varieties (KSV-4, KL-2 and NR 71168), three irrigationintervals (7, 14 and 21 days) and three plant densities (66,666, 53,333 and 44,444 ha-1). Splitplot design was used in the experiment and replicated three times with irrigation interval and varietyassigned to main plots and plant density allocated to the sub plots. The sub plots size was 4m x 3m(12m2), while the net plot was 6m2. Significantly longer panicles were found in KSV4 and KL-2 at 14days interval in 2008 and at 21 days interval in 2009. Higher grain weight per panicle was recorded inNR 71168 at 21 days irrigation interval in both years. NR 71168 variety out yielded other two varietiesin both years when irrigation interval was extended from 7 to 14 days. No significant response wasrecorded due to varying plant densities although, 66,666 gave higher grains output compared to otherplant densities studied. From this study it is concluded that NR 71168 variety at 14 days irrigation intervaland 66,666 ha-1 plant density under irrigation could be used at Kadawa in the Sudan savannahagro ecological zone of Nigeria

Effect of COVID-19 quarantine on the sleep quality and the depressive symptom levels of university students in Jordan during the spring of 2020

Objectives: This study was designed to assess the effect of COVID-19 home quarantine and its lifestyle challenges on the sleep quality and mental health of a large sample of undergraduate University students in Jordan. It is the first study applied to the Jordanian population. The aim was to investigate how quarantine for several weeks changed the students' habits and affected their mental health. Methods: A cross-sectional study was conducted using a random representative sample of 6,157 undergraduate students (mean age 19.79 ± 1.67 years, males 28.7%) from the University of Jordan through voluntarily filling an online questionnaire. The Pittsburgh Sleep Quality Index (PSQI) and the Center for Epidemiologic Studies-Depression Scale (CES-D) were used to assess sleep quality and depressive symptoms, respectively. Results: The PSQI mean score for the study participants was 8.1 ± 3.6. The sleep quality of three-quarters of the participants was negatively affected by the extended quarantine. Nearly half of the participants reported poor sleep quality. The prevalence of poor sleep quality among participants was 76% (males: 71.5% and females: 77.8%). Similarly, the prevalence of the depressive symptoms was 71% (34% for moderate and 37% for high depressive symptoms), with females showing higher prevalence than males. The overall mean CES-D score for the group with low depressive symptoms is 9.3, for the moderate group is 19.8, while it is 34.3 for the high depressive symptoms group. More than half of the students (62.5%) reported that the quarantine had a negative effect on their mental health. Finally, females, smokers, and students with decreased income levels during the extended quarantine were the common exposures that are significantly associated with a higher risk of developing sleep disturbances and depressive symptoms. Conclusions: Mass and extended quarantine succeeded in controlling the spread of the COVID-19 virus; however, it comes with a high cost of potential psychological impacts. Most of the students reported that they suffer from sleeping disorders and had a degree of depressive symptoms. Officials should provide psychological support and clear guidance to help the general public to reduce these potential effects and overcome the quarantine period with minimum negative impacts

IMECE2005-81122 ADHESION ENERGY OF SINGLE WALL CARBON NANOTUBE-POLYETHYLENE COMPOSITE: EFFECT OF MAGNETIC FIELD

ABSTRACT In this paper, we investigate the adhesion energy at the interface between single wall carbon nanotubes and polyethylene matrix with and without an external magnetic field. The carbon nanotubes are of two different chiralities --armchair (10,10), and zigzag (10,0), and the external high magnetic field is of 25 Tesla intensity. The study employs molecular dynamics simulations and concludes that the magnetic field decreases the interfacial adhesion energy although it increases the individual potential energies of the nanotubes, the polyethylene, and the composite

Frequency Tuned Planar Inverted F Antenna with L Shaped Slit Design for Wide Frequency Range.

yesA frequency tuned antenna has been designed to meet the coverage requirements of the DCS, PCS, UMTS and WLAN bands. The antenna consists of a main patch, and a planar inverted L (PIL) slot. The radiator patch is fed, and shorted, using simple feed lines with broadband characteristics. The handset represents the finite ground plane, and a varactor diode is mounted across the middle of the slot for tuning purposes. Initial tuning was obtained by placing lumped capacitors, instead of the varactor, over the radiator. Good agreement is obtained between the predicted and measured input return loss, gain and radiation pattern over the tuned frequency range.MSCR

Adoption Issues in DevOps from the Perspective of Continuous Delivery Pipeline

DevOps and Continuous Delivery (CD) are the terms that are always related to each other in Software Delivery and Operation Process area. DevOps introduces a significant agile perspective to deliver the software product in short cycle time that will reduce technical debt that is caused by delay. Continuous Delivery is one of the DevOps' practices that enables software organization to release new features and new products rapidly. However, the correct practices are still in ambiguity to the current CD process. This paper investigates the advantages and limitation of DevOps adoption to improve the CD process. A qualitative web survey has been conducted to identify the DevOps and Continuous Delivery advantages and adoption problems. 13 respondents' feedbacks have been collected and analyzed. Based on the survey, there are four significant DevOps' practices that need to be considered and developed as a proper guideline to introduce to practitioners

Refined clothespin relocation test and assessment of motion

Background: Advancements in upper limb prosthesis design have focused on providing increased degrees of freedom for the end effector through multiple articulations of a prosthetic hand, wrist and elbow. Measuring improvement in patient function with these devices requires development of appropriate assessment tools. Objectives: This study presents a refined clothespin relocation test for measuring performance and assessing compensatory motion between able-bodied subjects and subjects with upper limb impairments. Study Design: Comparative analysis Methods: Trunk and head motions of 13 able-bodied subjects who performed the refined clothespin relocation test were compared to the motion of a transradial prosthesis user with a single degree of freedom hand. Results: There were observable differences between the prosthesis user and the able-bodied group. The assessment used provided a clear indication of the differences in motion through analysis of compensatory motion. Conclusion: The refined clothespin relocation test provides additional benefits over the standard clothespin assessment and makes identification of compensatory motions easily identifiable to the researcher. While this paper establishes the method for the new assessment, further validation will need to be performed with more users