Synchronal measurement of flow structure and heat transfer of impingement jet

This paper will present the characteristics of flow behavior and thermal field of both free and
impingement jet issued from a circular orifice nozzle at Re=8900.The flow behavior of a single round
jet and impingement jet was observed by smoke flow visualization recorded by a high speed camera
using 5000 frame per second.Heat transfer coefficient on the impingement surface was measured by
means of infrared camera （TVS-8500,Avio） with a two-dimensional array of Indeum-Antimony （In Sb）
sensors varying in the separation distance between the nozzle and the target plate.The heat transfer
coefficient changes in time and spatial.Therefore,the root mean square distribution of the heat
transfer was obtained from the data.As a result,it was confirmed that the longitudinal vortex was
observed outside of the ring vortex,and then the longitudinal vortex was penetrated in the jet
flow.Moreover,the high value of root mean square of the heat transfer coefficient has spread radially
in stripy manner,which is caused as the results of the longitudinal vortexes flowing in the radial
direction on the impingement plate.     

Characterization of bacterial biofilm communities in tertiary treatment processes for wastewater reclamation and reuse

The concern with wastewater reuse as a sustainable water resource in urban areas has been growing. For the reclamation and distribution of wastewater, biofilm development deserves careful attention from the point of view of its promotion (e.g. biofiltration) and inhibition (e.g. clogging and hygiene problems). As the first step to control biofilm development, bacterial biofilm communities in tertiary treatment processes were characterized by using molecular biological methods. The result of clone library analysis showed that Nitrospirae-related (nitrite-oxydizing bacteria) and Acidobacteria-related (probably oligotrophic bacteria) groups were dominant. The ratio of the Nitrospirae-related group to the Acidobacteria-related group was associated with ammonia load, whereas other operational conditions (process, media, temperature, salt) did not clearly affect the phylum-level community or the dominant sequence of nitrifying bacteria. The result of real-time PCR also indicated that high ammonia load promotes the proliferation of nitrite- and ammonia-oxidizing bacteria. Regarding water supply systems, some researchers also have suggested the dominance of Nitrospirae- and Acidobacteria-related groups in biofilm formed on water distribution pipes. In tertiary wastewater treatment, therefore, it is concluded that oligotrophic and autotrophic bacteria are the dominant groups in biofilm samples because assimilable organic carbon is too poor to proliferate various heterotrophic bacteria.     

Situational awareness of construction equipment using GPS, wireless and web technologies

Situational awareness refers to the ability by equipment operators to sense their environment with the objective of increasing safety and improving productivity on construction sites. This paper reports on research related to situational awareness of construction equipment using differential Global Positioning System (DGPS), wireless and web-based technologies. In this investigation, the researchers developed and implemented technologies for vehicle tracking, and collision detection. The paper concludes with a summary of these applications, along with a discussion of the limitations of current implementations, and the required augmentation by other technologies.     

An experimental investigation of minimum fluidization velocity at elevated temperatures and pressures

Minimum fluidization data at elevated temperatures and pressures are relatively scarce in the literature. This study was undertaken to provide some new data under these conditions. Minimum fluidization velocities at temperatures up to 800°K and pressures up to 5 MPa were measured for uniformly-sized glass beads with diameters between 0.2 mm and 4 mm in beds ranging in diameter from 30 mm to 50 mm. The experimental results are compared with a number of empirical correlations from the literature to determine the validity of the correlations under these elevated temperature and pressure conditions.     

Preparation and Optical Properties of Transparent Glass-Ceramics Containing Cobalt(ll) Ions

Transparent glass-ceramics containing ZnAl₂O₄:Co²⁺ and LiGa₅O₈:Co²⁺ crystallites have been prepared by heat treatment of glasses in the zinc aluminosilicate and lithium gallate silicate systems, respectively. Crystalline LiGa₅O₈ was already precipitated in an as-prepared specimen, while ZnAl₂O₄:Co²⁺ precipitated from the glass upon heat treatment. The crystallite size varies from about 5 to 20 nm with increasing heat treatment temperature for both systems, and glass-ceramics containing crystallites of less than about 10 nm are transparent. The low-temperature optical absorption and emission spectra are compared with those of single crystals, indicating that almost all of the Co²⁺ ions replace Zn²⁺ ions in the ZnAl₂O₄ system, while some of the Co²⁺ ions are incorporated into the LiGa₃O₈ system, although the amount of Co²⁺ which remains in the glass matrix is rather large in the latter system.     

Surface properties of hydroxyapatite ceramic as new percutaneous material in skin tissue

Hydroxyapatite ceramic (HAC) was studied for utilization as a percutaneous device to prevent exit-site and tunnel infection along peritoneal dialysis catheters. As a result, it was found that HAC had good compatibility with skin tissue compared with silicone rubber and glassy carbon. In the present study, the surface properties of HAC after long-term implantation in skin of dogs was evaluated by scanning electron microscopic observation, solubility and bending tests. At 12 weeks after implantation, the surface of HAC was eroded severely by body fluid or cells, and the grain boundaries were clearly relieved. Ingrowth and adhesion of collagen into the etched ditch of HAC were observed. At 12 months, the eroded surface had been tightly covered and adhered to by a collagenous layer in spite of ripping off the surrounding fibrous capsule. In solubility tests, HAC dissolved at the rate of 0.23 mg cm^–2 HAC surface area per year. On the other hand, the bending strength decreased by about 10% at 4 weeks and scarcely decreased after that time. From these results, it was confirmed that the solubility of HAC produced tight contact and strong adhesion with skin tissue to prevent bacterial infection, and HAC was practical for a permanent percutaneous device.     

Discrete‐Valued Model Predictive Control Using Sum‐of‐Absolute‐Values Optimization

In this paper, we propose a new design method of discrete‐valued model predictive control for continuous‐time linear time‐invariant systems based on sum‐of‐absolute‐values (SOAV) optimization. The finite‐horizon discrete‐valued control design is formulated as an SOAV optimal control, which is an expansion of L¹ optimal control. It is known that under the normality assumption, the SOAV optimal control exists and takes values in a fixed finite alphabet set if the initial state lies in a subset of the reachable set. In this paper, we analyze the existence and discreteness property for systems that do not necessarily satisfy the normality assumption. Then, we extend the finite‐horizon SOAV optimal control to infinite‐horizon model predictive control (MPC). We give sufficient conditions for the recursive feasibility and the stability of the MPC‐based feedback system in the presence of bounded noise. Simulation results show the effectiveness of the proposed method.     

A study of real-time and 100 billion agents simulation using the Boids model

In high-performance computing of multi-agent systems, there often exists a load imbalance that slows down the calculation. In this paper, we discuss the parallelization of the Boids model for simulating a swarm intelligence. We apply the multi-level hierarchy of parallelism to the Boids model to mitigate the load-imbalance problem. To eliminate numerical errors due to parallelization, we apply pseudo-quadruple arithmetic. The parallel performance is evaluated on three major architectures, including many-core processors on an x86-based server with GPUs, and the Earth Simulator. The parallelization can decrease the negative effects of a load imbalance to almost zero in a simulation of 50 million agents. In addition, the parallelization guarantees the reproducibility of the results in a sequential execution. The strong scaling shows the potential to complete a simulation in real-time on the Earth Simulator. In addition, the weak scaling shows the ability to calculate 100 billion agents within a reasonable amount of time.