The present paper addresses cultivation of Chlorella vulgaris microalgae using airlift photobioreactor that sparged with 5% CO 2 /air. The experimental data were compared with that obtained from bioreactor aerated with air and unsparged bioreactor. The results showed that the concentration of biomass is 0.36 g l -1 in sparged bioreactor with CO2/air, while, the concentration of biomass reached to 0.069 g l -1 in the unsparged bioreactor. They showed also that aerated ioreactor.with CO2/air gives more biomass production even the bioreactor was aerated with air. This study proved that application of sparging system for ultivation of Chlorella vulgaris microalgae using either CO2/air mixture or air has a significant growth rate, since the bioreactors become more thermodynamically favorable and provide impetus for a higher level of production.
biofixing process
Tool wear is a major problem in machining operations because the resulting material loss gradually changes of the machine tool. There many factors may leads to material loss like; friction, corrosion, and also it’s happened by rubbing during machining processes between the work piece and the tool. Dimensional accuracy of the work piece, and also the surface finish will be reducing by tool wear. It can also increase cutting force. In this study, we focused on the effect of the coating process on crater wear problems. Crater wear is caused by the flow between the chip and the rake face of the tool, whereas flank wear is caused by the contact between the tool and the work piece. In reducing crater wear, aluminum titanium nitride (AlTiN) u
... Show MoreDue to the developments taking place in the field of communications, informatics systems and knowledge management in the current century, and the obligations and burdens imposed on the business organization to keep pace with these developments, the traditional methods of administrative decision-making are no longer feasible, as recent trends have emerged in management that focus on the need to rely on quantitative methods such as operations research.. The latter is one of the results of World War II, which appeared for the first time in Britain to manage war operations. The first method used in this field is the linear programming method. The use of operations research has developed greatly in the past years, and the methods of analysis in
... Show MoreIn this paper, the researcher suggested using the Genetic algorithm method to estimate the parameters of the Wiener degradation process, where it is based on the Wiener process in order to estimate the reliability of high-efficiency products, due to the difficulty of estimating the reliability of them using traditional techniques that depend only on the failure times of products. Monte Carlo simulation has been applied for the purpose of proving the efficiency of the proposed method in estimating parameters; it was compared with the method of the maximum likelihood estimation. The results were that the Genetic algorithm method is the best based on the AMSE comparison criterion, then the reliab
... Show MoreComplexity is the inherent characteristic of contemporary organizations. It is characterized by the intertwining and expansion of its relations, by the severe disorder and rapid change in its environment, which makes it suffer from a state of uncertainty in determining the direction of its future or the assessment of the rules governing its paths. All organizations tend to evolve with increasing sophistication, And to take measures that contribute to the simplification of the system as it moves towards complexity, allowing the administration to easily control its movement and directions, and the problem of complexity in the university is based on the entanglement and overlap in the goals and processes betwe
... Show MoreHigh-volume traffic with ultra-heavy axle loads combined with extremely hot weather conditions increases the propagation of rutting in flexible pavement road networks. Several studies suggested using nanomaterials in asphalt modification to delay the deterioration of asphalt pavement. The current work aims to improve the resistance of hot mix asphalt (HMA) to rutting by incorporating Nano Silica (NS) in specific concentrations. NS was blended into asphalt mixtures in concentrations of 2, 4, and 6% by weight of the binder. The behavior of asphalt mixtures subjected to aging was investigated at different stages (short-term and long-term aging). The performance characteristics of the asphalt mixtures were evaluated using the Marshall s
... Show MoreCombining ultrasonic irradiation and the Fenton process as a sono-Fenton process, the chemical oxygen demand (COD) in refinery wastewater was successfully eliminated using response surface methodology (RSM) with central composite design (CCD). The impact of two main influential operational parameters (iron dosage and reaction time) on the COD removal from wastewater generated by an Iraqi petroleum refinery facility was explored. Removal of 85.81% was attained under the optimal conditions of 21 minutes and 0.289 mM of concentration. Additionally, the results revealed that the concentration of has the highest effect on the COD elimination, followed by reaction time. The high R2 value (96.40%) validated the strong fit of the mo
... Show MorePolyetheretherketone (PEEK) has favorable biomechanical properties to be used as an implant material. Unfortunately, it is hydrophobic and does not promote cellular adhesion, which could result in poor integration with bone tissue. Bio-functionalization of PEEK surface with osteogenic peptides derived from bone extracellular matrix proteins is an exciting approach to encourage bone formation around the implant. In the current study, bone-forming peptide-2 was immobilized on PEEK surface using two different methods, using dopamine and a diglycidyl ether as conjugate compounds, respectively. Peptide quantification test revealed that the two strategies resulted in the most amount of peptides were attached with 0.5 mM concentration and no furth
... Show MoreA hydrophilic interaction chromatography has been investigated to separate 2-deoxycytidine chosen for nucleoside. A small molecule with specific features for human serum samples was 2-deoxycytidine tested. 2-deoxycytidine has been applied to self-made stationary hydrophilic phases (ZIC1 and ZIC5). The deoxycytidine (dCD) retention was investigated with varying concentrations of sodium acetate buffer, acetonitrile%, and pH. The results confirmed the hydrophilicity of 2-deoxycytidine. The exchanger retention mechanism was studied taking into account 2-deoxycytidine used for describing the interaction of hydrophilic and cation. For both ZIC1 and ZIC5 exchangers, we described and discussed the influence of chromatographic conditions (co
... Show MoreBackground: Dental implant is one of the most important options for teeth replacement. In two stage implant surgery, a few options could be used for uncovering implants, scalpel and laser are both considered as effective methods for this purpose. The Aim of the study: To compare soft tissue laser and scalpel for exposing implant in 2nd stage surgery in terms of the need for anesthesia, duration of procedure and pain level assessment at day 1 and day 7 post operatively using visual analogue scale . Materials and methods: Ten patients who received bilateral implants participated after healing period completed, gingival depth over each implant was recorded and then implant(s) were exposed by either scalpel or laser with determination for th
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