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

Promoting Ginger Oleoresin Production in Nigeria for Economic Growth and Sustainable Supply to User Industries

Nigeria ranks 2nd amongst top 10 ginger producers in the world with a production of 691,239 tonnes and its ginger is among the best, with its aroma, pungency and high oil and oleoresin content as distinct features. The most important form of ginger commercially is the dried form because it can be further processed in the industry to ginger powder, ginger oil and ginger oleoresin.  There is an increasing international demand for ginger oleoresins, especially for the production of alcoholic beverages, ginger ale and gingerbread. The global ginger oil market is expected to grow at a CAGR of 9.41 % from 2020 to 2025 to reach a total market size of US$189.431 million by 2025, increasing from US$110.435 million.  Nigeria, with the volume of ginger production and distinctive features of its ginger, should tap into this market demand. However, ginger is exported from Nigeria in the split-dried form while value-added products such as ginger powder, essential oils and oleoresin are imported at high cost. According to the Nigeria Customs Service data, 700,891 kg of resinoids and mixtures of odoriferous substances were imported to Nigeria from 2016 to 2019 at a value of ₦1.24 billion. To take advantage of the ever expanding global oleoresin market, formation of farmers clusters/cooperatives, development of farmers-processors linkages, quality assurance through Good Agricultural Practices, technology development, Public-Private Partnerships, development of Nigeria Industrial Standards (NIS) for oleoresins and import restrictions on ginger oleoresin are recommended. There is need for synergy amongst government agencies to harmonize and integrate various development plans and strategies for ginger value chain. Establishment of an institutional framework for proper coordination is also recommended to harmonize all the activities in the sector for greater impact. Keywords: Ginger, value addition, oleoresin, resinoids, ginger oil, export, import DOI: 10.7176/JNSR/12-22-03 Publication date: November 30th 202

Fast orthogonal derivatives on the star

AbstractIn many numerical problems there is the need for obtaining derivatives in the X and Y directions of m variables at each point on an n×n plane. We consider the case where these derivatives are obtained using spectral methods (i.e. n fast Fourier transforms of length n are taken for each component, multiplied by the wave numbers and reverse transformed).On the CDC STAR-100 all data points corresponding to a plane must be stored in contiguous locations if advantage is to be taken of the powerful pipeline hardware of the machine. This means that derivatives in one direction are obtained very efficiently while derivatives in the orthogonal direction require either the substantial overhead of transposition or the use of scalar operations with no benefits of pipelining.An algorithm is described that overcomes this problem by taking derivatives of all components simultaneously. This is made possible by perfect shuffling of data to effect a pseudo-transposition that permits the FFT routine to take transforms of all m components on a plane at one time. Practical experience with this algorithm for m=5 and n=32 shows a 10% speedup for X-derivatives and a 32% speedup for Y-derivatives over the conventional algorithms (in which X and Y derivatives are taken one component at a time and Y derivatives require transposition of data).A theoretical analysis based on available STAR-100 vector instruction timing data predicts that this algorithm is superior to the conventional algorithm for M ≥ 2, n ≤ 128 (problem sizes of practical interest). We show how further improvement in running time may be obtained if derivatives of several components on more than one plane are required.This analysis is applicable to the new generation of STAR computers (the CDC Cyber 203s) since vector instruction timings are essentially unchanged in the new machines

Towards Achieving Sugar Self-Sufficiency in Nigeria: A Review

Sugar is produced in 120 countries with about 110 countries producing from either cane or beet, and eight countries produce sugar from both cane and beet. The global sugar production in 2020/2021 was about 179 million tonnes with Brazil as the highest producer with 42 million tonnes. Sugarcane, on average, accounts for nearly 80% of global sugar production. Nigeria’s sugar industry has always faced challenges with national sugar requirements met through imports of raw sugar for local refining. The National Sugar Development Council (NSDC) was therefore set up in 1993 to catalyze the development of the sugar industry with a view to ensuring that Nigeria attains at least, 70% self-sufficiency in sugar requirement within the shortest possible time. Despite efforts by the Sugar Council, Nigeria still ranks among the top 10 sugar importing countries. The National Sugar Master Plan (NSMP) was launched in 2013 by the NSDC as a 10-year plan designed to transform the Nigerian sugar industry. This paper is aimed at reviewing the implementation of the Plan 8 years down the line. The efforts of the government to attain self-sufficiency in sugar through the National Sugar Master Plan have yielded little result. Production of sugar in Nigeria is yet to meet domestic demand thereby creating a huge supply gap that is met through import. According to NSDC data, sugar import increased from 955,675 tonnes in 2010 to 1,531,471 tonnes in 2020. The country spent an estimated USD 433.4 million on sugar importation in 2020, an increase from USD 382.3 million in 2019. Challenges of raw materials production include environmental constraints, lack of quality seed cane and suitable varieties, poor irrigation, lack of farm mechanization and poor capital. To improve sugarcane productivity, the cane industry should be restructured to improve efficiency and yields. Measures should also be put in place to promote the establishment of cane mills around the sugar estates and across the sugarcane producing areas. Keywords: Sugar, Sugarcane, Self-Sufficiency, Domestic demand, import, Master Plan DOI: 10.7176/JRDM/82-02 Publication date: January 31st 202

Evolution Sustainable Green Inner-wall with Flexible Floor Plan

The trend of renovate residential houses especially the interior of the house has become a common phenomenon for homeowners nowadays in Malaysia. This scenario is quiet concern because sometimes no modifications to comply with the law and the guidelines set by the government housing. Modifications with not done properly can cause injury and harm to families and the people around. To reduce this problem, the concept of sustainable inner walls with flexible floor plan should be incorporated in every house in Malaysia. This is because the wall is the basic structure of a building and usually serves as the border, supporting structures and dividing the space with another space. Wall also causes an increase of the price of a house. This is due to the increase in raw material costs and labor costs, land subsidence have to bear by the developer. The increasing in house prices is causing among Malaysians, especially young executives cannot afford to buy their first home. To reduce the price of the home, reduction in construction interior wall in wet construction should be done and replaced with the sustainable inner wall. This sustainable inner wall also can save the space and the owner simplify can added or reduced the room according their need without spending too much money for renovation in the future

Vanishing conharmonic tensor of normal locally conformal almost cosymplectic manifold

summary:The main purpose of the present paper is to study the geometric properties of the conharmonic curvature tensor of normal locally conformal almost cosymplectic manifolds (normal LCAC-manifold). In particular, three conhoronic invariants are distinguished with regard to the vanishing conharmonic tensor. Subsequentaly, three classes of normal LCAC-manifolds are established. Moreover, it is proved that the manifolds of these classes are $\eta$-Einstein manifolds of type $(\alpha,\beta)$. Furthermore, we have determined $\alpha$ and $\beta$ for each class

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

Urethral Extensibility Applied to Urethral Advancement

BACKGROUND: The male urethra in humans has a large capacity to extend under traction. This property is the main principle of the urethral advancement technique. AIM: We aimed to determine the safe limits of urethral mobilization and extensibility for reconstructive surgery of distal to midshaft hypospadias by applying urethral extensibility on the urethral advancement technique. Also, we wanted to evaluate the variable application of the gap-to-urethra (G:U) ratio from a cadaver to a live human body. METHODS: From November 2004 to February 2006, 20 boys aged from 2 to 16 years old underwent repair of midshaft to glanular hypospadias by urethral advancement technique. The ratio of G:U proposed for a safe limit of urethral extensibility (measured from normal, fresh human cadaveric urethras) applied to know if its application can help in decreasing the rate of late complications. The mean follow-up period was 10 months, which ranged from 4 to 16 months. RESULTS: Late complications were as follows: 25% meatal retraction (MR), 15% meatal stenosis (MS), and 5% fistula. Besides, MR and MS late complications associated with urethral mobilization of G:U ratio of less than 73%. CONCLUSION: The more the approximation in the application of the G:U ratio, the less the rate of MS and MR. Besides, urethral mobilization to the base of the penis helps to decrease the frequency of MS and MR. Furthermore, the type of complication, MR or MS, in urethral advancement correlates with the extent of urethral mobilization