Solids transport models comparison and fine‐tuning for horizontal,low concentration flow in single‐phase carrier fluid

We determined and fine‐tuned the solids transport models appropriate for predicting the single‐phase carrier fluid velocity to transport solid particles in conduits for horizontal, low concentration flow. A database with 538 experimental data points was compiled. A literature review was performed to determine the data ranges, forces, and mechanisms used to develop 44 models, and their velocity predictions were compared against the database using statistics. Using the dimensionless forms of the models and the data, the model parameters were adjusted to improve their accuracy and identify the dominant forces. At low concentrations: for liquid/solid flow from a bed of solids and gas/solid flow from the bottom of pipelines, the particle weight, and inertial and viscous forces dominate; for gas/solid flow from a bed of solids, the particle weight, and inertial, viscous, and adhesive forces play a role; and gaps exist in the data for large‐diameter pipes and high‐density gases. © 2013 American Institute of Chemical Engineers AIChE J, 60: 76–122, 2014     

Utilization of Whey and Grape Must for Citric Acid Production by Two Yarrowia lipolytica Strains

In this study, utilization of whey and grape must were investigated for citric acid production using Yarrowia lipolytica NBRC 1658 and a domestic strain Y. lipolytica 57. In addition to its use as a sole nutrient source, whey was also fortified with glucose or fructose as well as other nutrients. The best results for citric acid production were obtained in the medium containing whey supplemented with fructose. Maximum citric acid concentrations in this medium were 49.23 and 32.65 g/L for the domestic and NBRC 1658 strains, respectively. In grape must, maximum citric acid concentrations obtained using domestic and NBRC 1658 strains were 32.09 and 10.39 g/L, respectively. Both of the natural nutrient sources were found to be promising for utilization in citric acid production process. A domestic Turkish yeast strain was confirmed to be superior for citric acid production for the first time. This can be targeted for enhancing citric acid production efficiencies from locally available substrates such as whey or grape must.     

Influence of the harvesting year and fertilizer on the fatty acid composition and some physicochemical properties of linseed (Linum usitatissimum L.)

Sar? 85 (Linum usitatissimum L.) linseed variety was used in this study. Linseed was cultivated at 2008 (LS-08) and 2009 (LS-09) without fertilizer. In addition, at 2009 diammonium phosphate [(NH₄)₂HPO₄] and ammonium nitrate (NH₄NO₃) were applied (LSF-09). The linseeds were analyzed for protein, ash and oil contents and fatty acid compositions. There were differences among harvesting years for oil, protein and ash contents of the seeds. The greater oil and protein contents were obtained during LS-08 compared with LS-09. There were no significant difference in protein and ash content between LS-09 and LSF-09 while a significant difference was observed in oil content. Seed protein, oil and ash contents were significantly affected by the harvesting year, but only oil content was affected by the fertilizer treatment. There are significant differences in palmitic, stearic, oleic, ??-linolenic and arachidic acid between LS-08 and LS-09. While palmitic, stearic, oleic acid decreased, ??-linolenic and arachidic acid increased during 2009 harvesting year. LSF-09 has the highest amount of ??-linolenic acid. The fertilizing treatment seems to have an increasing effect on the amount of ??-linolenic acid, while it has a decreasing effect on the oleic acid content.     

Fast real-time caustics from height fields

Caustics are crucial in water rendering, yet they are often neglected in real-time applications due to the demanding computational requirements of the general-purpose caustics computation methods. In this paper we present a two-pass algorithm for caustics computation that is extremely fast and produces high-quality results. Our algorithm is targeted for commonly used height field representations of water and a planar caustic-receiving surface. The underlying theory of our approach is presented along with implementation details and pseudo codes.     

Characterization of closed-loop measurement accuracy in precision CNC milling

This study investigates the closed-loop measurement error in computer numerical controlled (CNC) milling as they relate to the different inspection techniques. The on-line inspection of machining accuracy using a spindle probe has an inherent shortcoming because the same machine-produced parts are used for inspection. In order to use the spindle probe measurement as a means of correcting deviations in machining, the magnitude of measurement errors needs to be quantified. The empirical verification was made by conducting three sets of cutting experiments, followed by a design of experiment with three levels and three factors on a state-of-the-art CNC machining center. Three different material types and parameter settings were selected to simulate a diverse cutting condition. During the cutting, the cutting force and spindle vibration sensor signals were collected and a tool wear was recorded using a computer vision system. The bore tolerance was gauged by a spindle probe as well as a coordinate-measuring machine. The difference between the two measurements was defined as a closed-loop measurement error and the subsequent analysis was performed to determine the significant factors affecting the errors. The analysis results showed the potential of improving production efficiency and improved part quality.     

Analysis of effects of sizes of orifice and pockets on the rigidity of hydrostatic bearing using neural network predictor system

This paper presents a neural network predictor for analysing rigidity variations of hydrostatic bearing system. The designed neural network has feedforward structure with three layers. The layers are input layer, hidden layer and output layer. Two main parameter could be considered for hydrostatic bearing system. These parameters are the size of bearing pocket and the orifice dimension. Due to importancy of these parameters, it is necessary to analyse with a suitable optimisation method such as neural network. As depicted from the results, the proposed neural predictor exactly follows experimental desired results.     

Exploratory spatial data analysis of the distribution of regional per capita GDP in Europe, 1980−1995

The aim of this paper is to study the space-time dynamics of European regional per capita GDP. A sample of 138 European regions over the 1980–1995 period provides clear evidence of global and local spatial autocorrelation as well as spatial heterogeneity in the distribution of regional per capita GDP. The detection of spatial clusters of high and low per capita GDP throughout the period is an indication of the persistence of spatial disparities among European regions. The dynamism of European regions is investigated by exploring the spatial pattern of regional growth. Implications for applied econometric work on the convergence of European regions are then suggested. Received: 11 September 2000 / Accepted: 11 March 2002 RID="*" ID="*"Previous versions of this article were presented at the 6th RSAI World Congress 2000 “Regional Science in a Small World”, Lugano, Switzerland, May 16–20, 2000 and the 40th ERSA Congress “European Monetary Union and Regional Policy”, Barcelona, Spain, August 29 – September 1, 2000. We would like to thank L. Anselin, R.J.G.M. Florax, A. Getis, C. Baumont, an and suggestions. We would also like to thank Eurostat: G. Decand and A. Behrens from the regional statistics section (division E4) as well as J. Recktenwald and I. Dennis for the help they provided on the Eurostat-Regio database. The usual disclaimer applies.     

Oil entrainment in vertical refrigerant pipingEntraînement de l''huile dans les tuyauteries frigorifiques verticales

The aim of this study is to investigate the required refrigerant speed, hence minimum refrigeration load, for carrying the lubricating oil up in vertical sections of refrigerant lines. It is assumed that the downward flow of the thin oil layer over the inner surface of the riser due to gravity is to be balanced with the upward flow of the oil film due to the shear force created by the upward flow of the refrigerant vapor. Velocities are converted to refrigeration capacities by considering a saturated cycle between specified condenser and evaporator pressures. General relationships thus developed are enumerated for R134a by preparing minimum capacity tables for copper suction and discharge risers.     

Using Tag-Match Comparators for Detecting Soft Errors

Soft errors caused by high energy particle strikes are becoming an increasingly important problem in microprocessor design. With increasing transistor density and die sizes, soft errors are expected to be a larger problem in the near future. Recovering from these unexpected faults may be possible by reexecuting some part of the program only if the error can be detected. Therefore it is important to come up with new techniques to detect soft errors and increase the number of errors that are detected. Modern microprocessors employ out-of-order execution and dynamic scheduling logic. Comparator circuits, which are used to keep track of data dependencies, are usually idle. In this paper, we propose various schemes to exploit on-chip comparators to detect transient faults. Our results show that around 50% of the errors on the wakeup logic can be detected with minimal hardware overhead by using the proposed techniques.