Utilizing open source software running in inexpensive high performance computing system for cfd applications

The high cost of conducting research is a significant issue for the successfulness of any research project. For research activities involving flow simulation, the licensing fee for the numerical software and the cost to acquire powerful machine are the main factors contributing to the high cost. This paper reports our experiences in setting up a cost effective way of doing computational fluid dynamics (CFD). The actions involve two areas, i.e., software and hardware. For the software, open source softwares are utilized, particularly the OpenFOAM(r) as the CFD package. For the hardware, a parallel computer made from a cluster of inexpensive desktop computer is constructed. This architecture is found able to meet our requirement in investigating various flow problems that include aeroacoustics, vibration and wind engineering for ventilation

Low-voltage ride-through based on neuro-fuzzy for grid-connected photovoltaic system

The increasing capacity of grid-connected photovoltaic (PV) over electrical power system might lead to voltage sags which affected the consumers and industries. To improve this situation, a simple control strategy of reactive power control using neuro-fuzzy is proposed in this paper to enable voltage regulation in a single-stage gridconnected PV system. An Artificial Neural Network (ANN) model is trained until a satisfactory result is obtained. After that, the trained neural network is combined with fuzzy logic. During the abnormal condition, the reactive current is controlled to inject reactive power for grid support and voltage recovery purpose. The dynamic behaviour of the system will be analyzed under a three-phase fault condition via MATLAB/Simulink. The simulation result shows that the proposed control strategy using neuro-fuzzy controller is effective in compensating desired reactive power during such faults. The voltage profile of the system has shown at least 9% of increment in all case studies. A swift recovery on the voltage can be achieved as well since the voltage returns to steady-state immediately when the fault is cleared

Transition metal oxide (NiO, CuO, ZnO)-doped calcium oxide catalysts derived from eggshells for the transesterification of refined waste cooking oil

This paper reports the synthesis of new transition metal oxide-modified CaO catalysts derived from eggshells for the transesterification of refined waste cooking oil. CaO is a well-known base catalyst for transesterification. However, its moderate basicity and low surface area have restricted its catalytic performance. Therefore, a new attempt was made to modify the CaO catalyst with transition metal oxides, including Ni, Cu and Zn oxides, via simple wetness impregnation method. The catalytic performance of the resulting modified CaO-based catalysts was evaluated through the transesterification reaction using refined waste cooking oil. The results showed that the NiO/CaO(10 : 90)(ES) catalyst calcined at 700 degrees C, demonstrated being highly potential as a catalyst. It gave the highest biodiesel production (97.3%) at the optimum conditions of 1 : 18 oil-to-methanol molar ratio, 6 wt% catalyst loading and 180 minutes reaction time as verified by response surface methodology (RSM). The high catalytic activity of NiO/CaO(10 : 90)(ES)(700 degrees C) was attributed to its high basicity (8.5867 mmol g(-1)) and relatively large surface area (7.1 m(2) g(-1)). The acid value and free fatty acids of the biodiesel produced under optimal process conditions followed the EN 14214 and ASTM D6751 limit with 0.17 mg KOH per g (AV) and 0.09 mg KOH per g (FFA), respectively

The structure of a major surface antigen SAG19 from Eimeria tenella unifies the Eimeria SAG family

In infections by apicomplexan parasites including Plasmodium, Toxoplasma gondii, and Eimeria, host interactions are mediated by proteins including families of membrane-anchored cysteine-rich surface antigens (SAGs) and SAG-related sequences (SRS). Eimeria tenella causes caecal coccidiosis in chickens and has a SAG family with over 80 members making up 1% of the proteome. We have solved the structure of a representative E. tenella SAG, EtSAG19, revealing that, despite a low level of sequence similarity, the entire Eimeria SAG family is unified by its three-layer αβα fold which is related to that of the CAP superfamily. Furthermore, sequence comparisons show that the Eimeria SAG fold is conserved in surface antigens of the human coccidial parasite Cyclospora cayetanensis but this fold is unrelated to that of the SAGs/SRS proteins expressed in other apicomplexans including Plasmodium species and the cyst-forming coccidia Toxoplasma gondii, Neospora caninum and Besnoitia besnoiti. However, despite having very different structures, Consurf analysis showed that Eimeria SAG and Toxoplasma SRS families each exhibit marked hotspots of sequence hypervariability that map to their surfaces distal to the membrane anchor. This suggests that the primary and convergent purpose of the different structures is to provide a platform onto which sequence variability can be imposed

Stakeholders Assessment of Constraints to Project Delivery in the Nigerian Construction Industry

The central goal of construction stakeholders is to successfully deliver projects to stated objective (s). However, for decades, construction projects have been plagued by perennial constraints of cost and time overruns, poor quality, and lack of sustainability. The objective of this paper is to identify and assess the constraints to construction project delivery, and to recommend solutions to enhance project performance. This paper adopted both quantitative and qualitative methods to establish the constraints in the Nigerian construction industry. A pilot survey and literature reviewed revealed a total of fifty (50) construction constraints, which were further classified into eight (8) major groups. Well-structured questionnaires were administered to construction stakeholders (client, consultant and contractor) in Abuja, the federal capital city of Nigeria. Relative Importance Index (RII) was used to analyze the data using Likert scale.  The results suggest that cost/time overrun related factors (inability to reduce project cost), Stakeholders interactive-related factors (inability to establish client value system), Client-related factors (Delay in interim payment and finance problem), and Labor/material-related factors (escalation of material prices and materials quality variability) are the most prevalent constraints in the Nigerian construction environment.  To mitigate the effects of these challenges, it is suggested that a formal innovative approach should be used by stakeholders to address the problems of poor communication, high project cost, and delay. Clients should also take measures to provide adequate funding and should promptly honor interim certificates