Automatic Blade Shape Optimization of a Three-Bladed Modified Savonius Turbine

In this study, the performance of a new wind turbine design derived from a conventional Savonius turbine is optimized by numerical simulation. The new design consists of three blades without passage between them (closed center). The coupling between the CFD codes (ANSYS Fluent) and the optimizer (OPAL) is used through an automatic procedure in-house codes, as documented, for example, in Thévenin et al.’s Optimization and Computational Fluid Dynamics (2008). A single-objective function (output power coefficient, Cp) is considered as the target of the optimization technique and the shape of the blade as an optimization parameter and relies on evolutionary algorithms. An optimal solution can emerge from this optimization study. By comparison between regular design (semi-cylindrical shape blades) and the optimal configuration, a considerable improvement (up to 7.13% at λ = 0.7) of the optimal configuration performance can be obtained in this manner.

Using Of Different Electrocoagulation Cell Configuration Parameters for Treating of Abu-Ghraib Dairy Products Wastewater

One of the most significant issues that people throughout the world will confront in the future years is a lack of clean and safe water. Anthropogenic activities, in particular, are polluting water systems. With rising population, urbanization, and climate change, water reuse has become a requirement in some areas of the globe, putting pressure on the development of effective water treatment methods for a range of contaminants. High biological oxygen demand (BOD), chemical oxygen demand (COD), oil-grease, and other pollutant loads define dairy sector effluent. Improved technology is required to address these issues. Electrocoagulation is a new type of therapy. It’s simple to use, ecologically friendly, and removes a wide range of contaminants from a variety of water types. The goal of this study was to see how operational factors such applied voltage, number of electrodes, distance between electrodes, electrode shape, and reaction time affected the electrocoagulation of actual dairy effluent. Aluminum and iron electrodes are used for this purpose. It was discovered that raising the applied voltage, reaction time, and decreasing the distance between electrodes improved COD, BOD, EC, TDS, color, and oil-grease removal efficiency. Moreover, switch between square, triangular electrodes and perforated cylindrical. The data show that electrocoagulation is effective at the maximum COD, BOD removal efficiency of first electrode at 20 holes of cylindrical shape is (88.03) %, (87.97) %, respectively. Second triangle shape is (100) %, (100) % respectively. Third square shape is (99.38) %, (99.42) % respectively. the maximum removal of TDS, EC efficiency of first electrode at 20 holes of cylindrical shape is (67.57) %, (62.34) %, respectively. Second triangle shape is (77.45) %, (67.68) % respectively. Third square shape is (81.96) %, (71.25) % respectively. The maximum color and oil-grease removal efficiency of first electrode at 20 holes of cylindrical shape is (100) %, (100) %, respectively. Second triangle shape is (100) %, (100) % respectively. Third square shape is (100) %, (100) % respectively. Electrocoagulation methods for the treatment of dairy wastewaters were shown to be successful in the research. Finally, the findings indicated that electrocoagulation is a technically feasible method for removing contaminants from dairy wastewaters.

Impact of post- amputation pain syndrome on the results of bone stump formation

Background. To the present day, a high rate of unsatisfactory amputation results still exists. The healing of the bone residual limb, the main support element of the residual limb, is of particular importance. Objective. To study the impact of postamputation pain syndrome on the nature of reparative processes in the bone residual limb. Methods. Three series of experiments were performed on 45 rabbits, 15 in each with mid-third thigh amputation and muscular plasty. In series 1 and 2, a perineural catheter was attached to the sciatic nerve stump during amputation, and mechanical irritation of the nerve was performed daily for 20 minutes in series 1 for 20 days. In series 2, 0.3 ml of 1% lidocaine was injected through the catheter into the circumference of the nerve twice daily for 20 days. Animals of series 3 served as a control. The follow-up periods were 1, 3, 6 months. The study method was histological with infusion of the vessels with ink-gelatin mixture. Results. In series 1, there was a sharp disturbance of the reparative process, which consisted in shape changes, resorption of the cortical diaphyseal plate, stump deformity, absence of bone closure plate formation, and microcirculatory disturbances. In most experiments of the 2nd series, organotypic stumps were formed with normalized microcirculation. In series 3, the results of the residual limb formation were better than in series 1, but worse than in series 2. Conclusion. In the absence of pain syndrome, the bone stump after amputation at the diaphysis level over a period of 1, 3, 6 months retains its cylindrical shape, the structure of the cortical diaphyseal plate, the content of the medullary canal with normal microcirculation, the formation of the bone closure plate, and the completion of the reparative process. The presence of postamputation pain syndrome in the stump distorts the course of the reparative process with the development of pathological remodeling of bone tissue.

Analysis of soil characteristics on expansive clay stabilization using shell ash

Expansive clay is one of the problems in construction work. The soil has the characteristics of being easy to expand when exposed to water, causing a decrease in the strength value of the soil. The can be overcome by stabilizing the soil. The soil is formed from weathering and contains the mineral montmorillonite. The soil is very sensitive to moisture content, has a high shrinkage rate, thus interfering in construction work. Therefore, additional materials are needed to overcome the problem, one of which is soil stabilization. The study aimed to stabilize the expansive clay soil. This is done by analyzing the physical and mechanical properties of expansive clay with a shell ash mixture. Expansive clay is taken directly (undisturbed) or disturbed. Undisturbed soil is taken using a tube, so that the soil is not disturbed by outside air, while disturbed soil is taken using a shovel and then put into a sack container. Expansive clay stabilization method lies in adding the percentage of shell ash mixture (5 %, 10 %, 15 %, and 20 %). The soil, the initial moisture content (γd) of which has been determined, is mixed, then molded into a cylindrical shape. The mold was stored in a desiccator, then watered with 5 % water every day until the soil became saturated. Then, using a Proctor test, chemical tests (soil chemical test, soil mineral test), physical tests (soil moisture, Atterberg limit), and mechanical tests (unconfined compression test, compaction test, swelling test) were carried out. The results showed that the addition of an oyster shell ash stabilizing agent to expansive clay affected the physical and mechanical properties of the soil. The addition of shell ash can reduce soil moisture with various plasticity indexes. While the soil stress value decreased, the swelling of the soil increased significantly above the original soil.

STUDY OF THE INFLUENCE OF TECHNOLOGICAL PARAMETERS ON THE GRANULOMETRIC CHARACTERISTICS OF SUBMICRON ALUMINUM OXIDE IN α-FORM

Experimental studies of the influence of technological parameters of grinding alumina raw materials in a ball mill on the kinetics of the grinding process and the granulometric characteristics of activated alumina in the α-form have been carried out. It is found that the use of spherical grinding bodies leads to the formation of a specific four-modal granulometric composition with maxima: 0.5; 4.0; 50.0 and 400.0 microns, respectively. The disadvantage of using spherical grinding bodies is the uneven distribution of the introduced intensifier additive (PEG), which in turn causes adhesion of fine particles and the appearance of aggregates. This is especially pronounced at n = 100 rpm. When using grinding bodies of cylindrical shape, on the contrary, there is a tendency towards a bimodal nature of the distribution of particles with maxima in the regions of 0.4 and 4 μm, respectively, regardless of the rotation speed of the drum (n). The use of cylpebs does not provoke agglomeration of the fine particle fraction, which is observed in the case of spherical grinding bodies. When analyzing the kinetics of grinding alumina raw materials, two main stages of the process are identified. The first stage corresponds to the active fragmentation of large initial aggregates into constituent crystallites by the cleavage mechanism. The second stage corresponds to a change in the grinding mechanism from crushing to abrasion. It is found that carrying out the grinding process for 10 hours using cylindrical grinding bodies at n = 100 rpm and φ = 0.35 provides a high yield of the submicron fraction of the target product (1 μm) - up to 20 wt. %.

Turbulence Enhancement and Mixing Analysis for Multi-Inlet Vortex Photoreactor for CO2 Reduction

In this article, we describe a prototype photoreactor of which the geometrical configuration was obtained by Genetic Algorithms to maximize the residence time of the reactant gases. A gas reaction mixture of CO2:H2O (1:2 molar ratio) was studied from the fluid dynamic point of view. The two main features of this prototype reactor are the conical shape, which enhances the residence time as compared to a cylindrical shape reference reactor, and the inlet heights and position around the main chamber that enables turbulence and mass transfer control. Turbulence intensity, mixing capability, and residence time attributes for the optimized prototype reactor were calculated with Computational Fluid Dynamics (CFD) software and compared with those from a reference reactor. Turbulence intensity near the envisioned catalytic bed was one percentage point higher in the reference than in the optimized prototype reactor. Finally, the homogeneity of the mixture was guaranteed since both types of reactors had a turbulent regime, but for the prototype the CO2 mass fraction was found to be better distributed.

Unusual Morphotypes of the Giant Barrel Sponge off the Coast of Barbados

Giant barrel sponges (GBSs) belong to a cryptic species complex (Xestospongia spp.) and are found on tropical reefs worldwide. Over their range, including most of the Caribbean, GBSs have a cylindrical shape, with variation in height, diameter and surface complexity. However, off the southwest coast of Barbados, GBSs mostly exhibit a clam shape or a tub shape, interspersed with a few that have the normal barrel morphotype, suggesting that this variation is not due to environmental factors. Haplotype identification (mtDNA-COI) of six clam and six normal sponges indicated no clear genetic differentiation based on morphotype; hence, this morphological variation remains unexplained.

Double-Layer Micro Porous Media Burner from Lean to Rich Fuel Mixture: Analysis of Entropy Generation and Exergy Efficiency

Porous media burner (PMB) is widely used in a variety of practical systems, including heat exchangers, gas propulsion, reactors, and radiant burner combustion. However, thorough evaluations of the performance of the PMB based on the usefulness of entropy generation, thermal and exergy efficiency aspects are still lacking. In this work, the concept of a double-layer micro PMB with a 23 mm cylindrical shape burner was experimentally demonstrated. The PMB was constructed based on the utilization of premixed butane-air combustion which consists of an alumina and porcelain foam. The tests were designed to cover lean to rich combustion with equivalence ratios ranging from ϕ = 0.6 to ϕ = 1.2. It was found that the maximum thermal and exergy efficiency was obtained at ϕ = 1.2 while the lowest thermal and exergy efficiency was found at ϕ = 0.8. Furthermore, the findings also indicated that the total entropy generation, energy loss, and exergy destroyed yield the lowest values at ϕ = 1.0 with 0.0048 W/K, 98.084 W, and 1.456 W, respectively. These values can be stated to be the suitable operating conditions of the PMB. The findings provided useful information on the design and operation in a double-layer PMB.

Modelling vibrations of axial piezoelectric generator with active base

Modelling of an axial-type piezoelectric generator (PEG) is considered. PEG is an integral part of the system for converting mechanical vibration energy from the environment into electrical energy. The energy generator has an axial type of the configuration of elements, aimed on using bending and compressive loads simultaneously on piezoelectric elements. The base of the generator is made as an active pinching. A feature of PEG is that the generator has two types of piezoelectric elements: (1) elements located on the substrate in the form of a bimorph and (2) piezoelectric elements of a cylindrical shape, fixing the generator base, located on the same axis. PEG has a symmetrical structure about the center of proof mass. The results of modal and harmonic analysis of vibrations are given for vibration excitation of the PEG base in a certain frequency range. The analysis of the output characteristics is given.

Calcium fluctuations drive morphological patterning at the onset of Hydra morphogenesis

Morphogenesis in animal development involves significant morphological transitions leading to the emerging body plan of a mature animal. Understanding how the collective physical processes drive robust morphological patterning requires a coarse-grained description of the dynamics and the characterization of the underlying fields. Here I show that calcium spatial fluctuations serve as an integrator field of the electrical-mechanical processes of morphogenesis in whole-body Hydra regeneration and drive the morphological dynamics. We utilize external electric fields to control the developmental process and study a critical transition in morphogenesis, from the initial spheroidal shape of the tissue to an elongated cylindrical shape defining the body plan of a mature animal. Morphogenesis paused under external voltage is associated with a significant increase of the calcium activity compared with the activity supporting normal development. The enhanced calcium activity is characterized by intensified spatial fluctuations, extended spatial correlations across the tissue and faster temporal fluctuations. In contrast, the normal morphogenesis process is characterized by relatively moderate calcium fluctuation activity and restrained spatial correlations. Long-range communication however, is essential for development. Blocking gap-junctions halts morphogenesis by suppressing the long-range electrical communication, severely reducing the overall calcium activity and enhancing its localization in the tissue. Normal calcium activity is resumed following the wash of the blocker drug, leading to a morphological transition characterizing a normal regeneration process and the emergence of a mature animal. Our methodology of controlling morphogenesis by a physical electric field allows us to gain a global statistical view of the dynamics. It shows that the normalized calcium spatial fluctuations exhibit a universal shape distribution, across tissue samples and conditions, suggesting the existence of a global constrain over these fluctuations. Studying the correlations in space and time of the calcium fluctuation field at the onset of morphogenesis opens a new vista on this process and paints a picture of development analogous to a dynamical phase transition.