The Role of Micro Vortex in the Environmental and Biological Processes

This work presents a short review of the theoretical developments in the application of vortex dynamics to the processing of environmental and biological systems. The mechanisms of complex fluid-particle interaction in vortex dominated and non-vortex dominated flows are briefly discussed from theoretical and practical perspectives. Micro vortex propagation, characteristics and their various applications in environmental process engineering are briefly discussed. Several existing and potential applications of vortex dynamics in turbulent flows are highlighted and as well as the knowledge gaps in the current understanding of turbulence phenomenon with respect to its applications in the processing of solid-liquid suspension and biological systems

Hydrodynamic Characterization of Physicochemical Process in Stirred Tanks and Agglomeration Reactors

A short review of the state of the art in experimental and computational fluid dynamics (CFD) characterization of micro-hydrodynamics and physicochemical processes in stirred tanks and agglomeration reactors is presented. Results of experimental and computational studies focusing on classical mixing tanks as well as other innovative reactors with various industrial applications are briefly reviewed. The hydrodynamic characterization techniques as well as the influence of the fluid dynamics on the efficiency of the physicochemical processes have been highlighted including some of the limitations of the reported modeling approach and solution strategy. Finally, the need for specialized CFD codes tailored to the specific needs of fluid-particle reactor design and optimization is advocated to advance research in this field

Impending Natural Gas Supply Glut and Biogas Developments in Europe: Economic and Environmental Implications

The recent trend in the global energy consumption as a result of growing demand from rapidly industrializing countries such as China, India, Brazil, etc. have called for an urgent need to find an alternative and economical source of energy. Natural gas from various sources (conventional, non-conventional) has long been touted as a potential replacement for heavily-polluting crude oil and coal. The recent development in natural-gas production has seen output from non-conventional sources such as shale bed increasing significantly in countries with substantial investment in pipeline and technology for the exploitation and production of gas from this new source such the US. This has created a gas boom in countries with a head-start in tapping into this economical but environmentally controversial source, as well as a slump in global natural-gas prices. In Europe, there has been a stiff opposition to gas production from non-conventional sources such as shale gas on environmental ground, and the focus here is on securing gas supply from existing conventional sources through long-term contracts with major gas suppliers as well development of environmentally friendly alternatives such as biogas from biomass. This paper examines the effects of the impending natural-gas supply glut in the global energy market with respect to biogas developments in Europe and environmental aspects of both sources of energy. Keywords: Natural gas; Biogas; Shale gas, Substrates

Determinants of Profitability Among Agricultural Equipment Fabricators in Oyo State, Nigeria

The study examined enterprise profitability among agricultural equipment fabricators. It was conducted in Oyo State, Nigeria using a multistage sampling procedure to select the 48 respondents from whom data were collected using a structured questionnaire. Percentage was used to analyse the socioeconomic and enterprise characteristics of the respondents, while gross margin analysis was used to determine the profitability of the enterprise. A linear regression model was used to ascertain the drivers of enterprise profitability among respondents. Findings revealed that over half (54.4%) of the fabricators produced processing equipment, while fewer (28.2%) produced farm tools. Most of the fabricators operated with a mean workshop space of 1.3 m2. The gross margin analysis showed a total revenue of N95,302,900 exceeding the total cost of production (N20,374,205), indicating (N74,928,695) profitability of their enterprise with a N3.68 return on investment per Naira. Fabrication being a secondary occupation (?=0.340), and business registration with the Corporate Affairs Commission (?=0.473) significantly influenced profitability among the respondents. This study recommends regulating the fabrication sector through policies, ensuring that fabricators register their outfits, provision of credit, and training by the government to significantly enhance the standardization of outputs and increase the units of production, hence, improving the enterprise's profitability

Evaluation of the Engineering Properties of Asphaltic Concrete Composite Produced from Recycled Asphalt Pavement and Polyethylene Plastichttps://figshare.com/s/def106ee031aecea8c33

The processed data and the figures support the findings of our research work that was carried out to evaluate the engineering properties of asphaltic concrete Composite produced from recycled asphalt pavement and polyethylene plastic</p

Experimental and CFD Studies of the Hydrodynamics in Wet Agglomeration Process

In this study, an experimentally validated computational model was developed to investigate the hydrodynamics in a rotor-stator vortex agglomeration reactor RVR having a rotating disc at the centre with two shrouded outer plates. A numerical simulation was performed using a simplified form of the reactor geometry to compute the 3-D flow field in batch mode operations. Thereafter, the model was validated using data from a 2-D Particle Image Velocimetry (PIV) flow analysis performed during the design of the reactor. Using different operating speeds, namely 70, 90, 110, and 130 rpm, the flow fields were computed numerically, followed by a comprehensive data analysis. The simulation results showed separated boundary layers on the rotating disc and the stator. The flow field within the reactor was characterized by a rotational plane circular forced vortex flow, in which the streamlines are concentric circles with a rotational vortex. Overall, the results of the numerical simulation demonstrated a fairly good agreement between the Computational Fluid Dynamics (CFD) model and the experimental data, as well as the available theoretical predictions. The swirl ratio &beta; was found to be approximately 0.4044, 0.4038, 0.4044, and 0.4043 for the operating speeds of N = 70, 90, 110, and 130 rpm, respectively. In terms of the spatial distribution, the turbulence intensity and kinetic energy were concentrated on the outer region of the reactor, while the circumferential velocity showed a decreasing intensity towards the shroud. However, a comparison of the CFD and experimental predictions of the tangential velocity and the vorticity amplitude profiles showed that these parameters were under-predicted by the experimental analysis, which could be attributed to some of the experimental limitations rather than the robustness of the CFD model or numerical code

Production of polyhydroxyalkanoate (pha) by pseudomonas aeruginosa (ol405443) using agrowastes as carbon source

The search for cost-effective substrates for the manufacturing of valuable products has led to the use of agrowastes as alternative sources of reducing sugar. Numerous bacteria build up polyhydroxyalkanoates (PHAs) as storage materials. This research aimed to produce PHA from Pseudomonas aeruginosa using agrowastes as carbon sources. The agrowastes (corncob, plantain peduncle and sugarcane bagasse) were treated with 1 % NaOH and analysed. The agrowastes were hydrolysed using cellulase produced by Aspergillus niger isolated from agrowastes dumpsite. The agrowaste hydrolysate was used in place of glucose for PHA production in a submerged fermentation. Nile blue A test and Sudan black test showed positive results for the isolate with a bright orange fluorescence on irradiation with UV light and was identified as Pseudomonas aeruginosa (accession number 0L405443). Sugarcane bagasse gave the highest potential for PHA production with PHA values of 5.86 mg/mL, followed by corn cob (5.29 mg/mL) and the least was obtained in plantain peduncle with a yield of 3.58 mg/mL. The findings using response surface methodology (RSM) for optimization show that all the four factors (carbon source, pH, temperature and incubation time) were statistically significant (P < 0.05) for PHA production. The optimum PHA production was attained under culture conditions of 24 h, 38 °C, pH 6.5, and 3 % carbon source. The PHA produced from 10 L of MSM was quantified to be 10.57 g under these conditions. The study revealed that Pseudomonas aeruginosa 0L405443 is a local bacterial strain utilized for the production of PHA using affordable, sustainable and easily available agrowastes hydrolysate as substrate